General

Question 1

Inherited genetic defect leading to decreased chondrocyte proliferation in the growth plate of long bone

Answer 1

GOF mutation in FGF-R3 (cell signaling molecule) -> constant activation inhibits chondrocyte proliferation -> short limbs

Question 2

What IL mediates anaphylactic rxn

Answer 2

IL-4 from Th2 cells

Question 3

What does inulin VOD estimate

Answer 3

Extracellular fluid volume (so plasma + interstitial)

Question 4

What does RISA VOD estimate

Answer 4

Plasma volume

Question 5

What does Cr-RBC estimate

Answer 5

Blood volume

Question 6

What do D2O, antipyrine, or tritiated water estimate

Answer 6

Total body water

Question 7

Sudden cardiac death from cocaine, what enzyme is elevated in myocardial cells prior to death?

Answer 7

PFK-1 - rate-limiting enzyme of glycolysis, b/c myocardial cells switch to anaerobic metab and glycolysis becomes the sole source of ATP

Question 8

Formula to calculate steady state concentration

Answer 8

Dosing rate = Css x Clearance / F

F = 1 w/ IV

Question 9

Starting with 285 mOsmol/kg H2O extracellular fluid osmolality and 42 L total body water, consume 3 L water and 10 mEq sodium, what’s now the extracellular fluid osmolality?

Answer 9

Sodium consumed is very little so no effect (normal extracellular sodium conc is 140 mEq/L)
Consume 3 L so this will decrease (dilute out) extracellular osmolality by about 7% (3/42) –> so pick whatever is less than 285 mOsmol/kg but still in reasonable range

Question 10

4-yo girl w/ ravenous apatite and rapid weight gain, floppy as a child, what’s the finding on chromosome?

Answer 10

Abnormal methylation on chr 15

Prader-Willi

Question 11

Difference bet what happens to APC and ras in colon cancer

Answer 11

Deletion or LOF mutation in APC (tumor suppressor)

ras is proto-oncogene so it would be amplified, induced, or have GOF mutation

Question 12

What would you find in IgA deficiency on top of recurrent mucosal infection

Answer 12

Increased atopy (atopic allergy) -> switches to IgE more since can’t make IgA

Question 13

What would a pt w/ C3 deficiency be more susceptible to?

Answer 13

type III hypersensitivity - b/c it’s immune complex mediated, and there’s not enough C3 around to clear these complexes from blood stream

Question 14

Ab against what structure in measles virus is protective?

Answer 14

Hemagglutinin

Question 15

The GC in LN contains cells undergoing what processs?

Answer 15

Isotype switching

Question 16

Where do you harvest saphenous vein?

Answer 16

Medial thigh inferolateral to pubic tubercle (branch off of external iliac vein)

Question 17

Lateral foot sensation?

Answer 17

SurAL nerve

Question 18

Medial foot sensation?

Answer 18

Saphenous nerve

Question 19

What kind of protein is n-MYC?

Answer 19

Transcription factor

Question 20

What kind of protein is k-RAS? And what pathway does it participate in?

Answer 20

GTPase (G-protein signaling)

Ras/MAP kinase pathway

Question 21

How do you calculate attack rate?

Answer 21

Ratio of # of people who were exposed and developed illness over # of people who were exposed
Example: to calculate attack rate of potato salad, both top and bottom numbers will have to include people who had potato salad in combination with other things as well (not just potato salad alone)

Question 22

Thymic aplasia + hypogammaglobulinemia in infancy. What’s the defect?

Answer 22

SCID
Not common variable immunodeficiency because that wouldn’t be so severe as to have thymic aplasia and that would present after neonatal period

Question 23

What’s responsible for variable presentations in 2 siblings w/ the same mitochondrial disease?

Answer 23

Heteroplasmy -> different organellar genomes (mutated and wild type) appearing w/in a single cell

Question 24

What do most homeobox-containing genes code for?

Answer 24

Transcription factors that play a role in morphogenesis

Question 25

Pt w/ ciliary dysfx, what's the disease association?

Answer 25

Kartagener's syndrome (half of pts w/ primary ciliary dyskinesia): persistent bronchial dilatation (bronchiectasis), situs inversus, male infertility, recurrent sinusitis/otitis Defects in dynein arms (containing ATPase that generates energy for microtubules in cilia)

Question 26

What enzyme in liver is important to be able to use TG breakdown product for energy and glucose synthesis?

Answer 26

Glycerol kinase Takes glycerol and converts it to glycerol 3-P, which is further converted to DHAP, which is fed into glycolysis (energy), gluconeogenesis, or used for TG synthesis in adipose tissue

Question 27

Losing neutral aromatic AA in urine. Sx of ataxia, pruritic skin lesions and loose stools. What would sx most likely respond to?

Answer 27

Niacin Neutral aromatic AA is tryptophan, and the disease is Hartnup disease (intestinal and renal absorption of neutral AAs is defective) -> no tryptophan means no niacin synthesis -> niacin deficiency manifests as 3D's (dementia, diarrhea, dermatitis)

Question 28

The naked RNA of what virus stays infectious on its own? Grows on nasal exudate

Answer 28

Rhinovirus For a naked RNA to be infectious it needs to be SS+ (so equivalent to mRNA) -> able to use host's machinery for translation If SS- or DS it needs a specific viral polymerase contained in complete virion

Question 29

Formula for number needed to harm?

Answer 29

1 / attributable risk | Attributable risk = risk of developing disease if treated - risk of developing disease if untreated

Question 30

Carrier frequency from mom's population is 1/30, carrier frequency from dad's population is 1/100. What's the probability of child having the disease if the disease is AR?

Answer 30

If mom is a carrier (Aa), the chance that she's passed on a recessive allele (a) is 1/2 So chance that mom is a carrier AND passed on recessive allele is 1/2 x 1/30 Similarly for dad = 1/2 x 1/100 So probability that both events will occur is a product of these 2 independent events = 1/2 x x 1/30 x 1/2 x 1/100 = 1/12000

Question 31

What 4 things are Marfan pts susceptible of?

Answer 31

Mitral valve prolapse Cystic medial degeneration of aorta (thus high risk for aortic root dilatation&aortic dissection -> most common cause of death after infancy) Lens displacement Skeletal abnormalities (long extremities and fingers, scoliosis and/or kyphosis)

Question 32

What do eosinophils contribute to host defense against schistosomiasis?

Answer 32

Ab-dependent cellular cytotoxicity (ADCC) -> because free IgE binds parasite first, then its heavy chain binds IgE Fc receptor on eosinophil surface -> eosinophils then release major basic proteins and enzymes from granules This is NOT the same thing as type 1 hypersensitivity rxn, which eosinophils help regulate by degrading histamine (thus tones down severity) and facilitating inflammation. This type 1 rxn is mediated mainly by mast cells and basophils whose Fc receptor on the membrane is already bound to IgE (not free IgE) and are just waiting for Ag cross linking

Question 33

What's a root cause analysis?

Answer 33

Identifies what, how, and why a preventable adverse outcome occurred -> collection of data thru interviewing ppl involved in the steps leading to the outcome So if pt died bc he didn't receive the med he needs, the system based approach to fixing the problem is to interview pharmacy, nursing, med staff on the unit where this occurred (not jump right into creating alert system, etc)

Question 34

What Ab differ most between IPV and OPV?

Answer 34

IPV is administered IM and is killed virus OPV is administered orally and is live attenuated virus OPV will generate more mucosal IgA (ie in intestine) because specific mucosal surface is directly stimulated by Ag (general principle that applies to all vaccine)

Question 35

Little boy in fasting state developed seizure and was found to have hypoglycemia with low ketones

Answer 35

Acyl-CoA DH deficiency so can't make ketone bodies in fasting state

Question 36

What are the 5 most important steps in preventing infection at central venous catheter?

Answer 36

Proper hand washing Full barrier precautions during insertion Chlorhexidine for skin disinfection (don't need to pretreat w/ antibiotic ointment or oral antibiotics) Avoids femoral insertion site (subclavian best, internal jugular second best) Removes catheter when no longer needed (but don't need scheduled catheter replacement)

Question 37

Know exposure status (smoking), follow ppl for years and see if they develop cancer. What kind of study is this called?

Answer 37

Prospective cohort

Question 38

Diff between retrospective cohort study and case control study

Answer 38

In retrospective cohort, exposure status is determined retrospectively and then they're tracked from that point (typically using medical records) -> exposure focused In case control, you select pts w/ particular disease (cases), and without disease (control) (instead of selecting from exposure status) and look back to see if they were exposed -> disease focused

Question 39

What should you remove from the diet of a child w/ aldolase B deficiency?

Answer 39

Sucrose (glu + fruc) and fructose

Question 40

Given a graph of time vs. plasma concentration, and there are two lines, one for IV dose of drug (linear line w/ negative slope) and one for oral dose of drug (inverted asymmetric parabola). How do you calculate oral bioavailability?

Answer 40

Takes area under curve of oral graph and divide it by area under curve of IV graph In reality, the calculation is F = (area under oral curve x IV dose) / (area under IV curve x oral dose)

Question 41

Formula for relative risk calculation? What kind of study is it used for?

Answer 41

Risk among exposed divided by risk among unexposed RR = a/(a+b) / c/(c+d) For cohort study (study exposure) (relative rate can also be calculated for cohort study)

Question 42

Formula for odds ratio calculation?

Answer 42

OR = a/c / b/d | For case-control study (study disease)

Question 43

Homeless alcoholic man w/ cavitary lung lesion & air-fluid level. What most likely happened?

Answer 43

He aspirated oropharyngeal content. | NOT gastric content b/c that's more likely to cause chemical pneumonitis than lung abscess.

Question 44

What enzyme fx primarily in the nucleolus?

Answer 44

Nucleolus is the site of ribosomal component synthesis and assembly (proteins made in cytosol transported in to assemble there) RNA polymerase I is thus the enzyme (makes most of ribosomal components)

Question 45

Where does parvovirus B19 replicate? What does it attach to?

Answer 45

``` Bone marrow (loves erythrocyte precursors) -> replication causes cell death Attaches to erythroid cells via blood group P antigen (globoside) ```

Question 46

What vitamin deficiency can manifest years after dietary insufficiency?

Answer 46

B12 (cobalamin) b/c huge liver reserve

Question 47

Single nucleotide deletion results in decreased protein production. What mutation is this?

Answer 47

Frameshift! | The other mutations (silent, missense, nonsense) are all caused by SUBSTITUTION not DELETION (or insertion)

Question 48

Pt expressed DNR wish to spouse orally. Now incapacitated. How do you proceed?

Answer 48

ORAL DNR counts! | The correct answer is attend to pt's comfort and allow his family to be present w/ him as he is dying

Question 49

When is it acceptable to treat or prescribe to family and friends?

Answer 49

not ALWAYS unethical to do so | Acceptable in emergency situations when no other physicians are available

Question 50

What's a control in case-control study?

Answer 50

Ppl w/ no disease of interest REGARDLESS OF EXPOSURE

Question 51

How do you get fast DNA replication in eukaryotes?

Answer 51

Multiple origins of replication (only single in prokaryotes)

Question 52

What determines potency? What determines efficacy?

Answer 52

Potency: depends on affinity (higher affinity/lower ED50 -> more potent) and penetration -> left graph is more potent than right (shifting right w/ the same efficacy might be a result of the same basic pharmacologic agent but w/ a competitive antagonist mixed in) Efficacy: Emax regardless of dose -> top graph is more efficacious than bottom graph

Question 53

Stab wound perpendicular to skin above the clavicular between midclavicular and lateral sternal lines. What do you injure?

Answer 53

Lung pleura

Question 54

What's the one way you can get accessory nerve damage?

Answer 54

Surgery involving pos. triangle of neck (bound by clavicle, pos. border of sternocleidomastoid m., and ant. border of trapezius m.)

Question 55

What's the one way you can get injury to ansa cervicalis? What are the nerve roots and what does it innervate?

Answer 55

Penetrating trauma to the neck above cricoid cartilage Nerve roots C1-C3 Innervates the muscles in front of the neck: sternohyoid, sternothyroid, omohyoid m.

Question 56

What's the one way you can get injury to carotid body?

Answer 56

Trauma to the level just inferior to the hyoid bone

Question 57

Papillledema, dry skin, hepatosplenomeg. What's the vitamin abnormality?

Answer 57

Vitamin A excess

Question 58

Older, mentally slow woman who is lemon colored, has a smooth tongue, and shuffling broad-based gait. What's the vitamin abnormality?

Answer 58

Vitamin B12 deficiency

Question 59

Diarrhea, abd bloating, false negative stool guaiac. What's the vitamin abnormality?

Answer 59

Vitamin C excess

Question 60

Hemorrhagic stroke in adults and necrotizing enterocolitis in children. What's the vitamin abnormality?

Answer 60

Vitamin E excess

Question 61

Cheilosis, corneal vascularization, stomatitis, glossitis, dermatitis. What's the vitamin abnormality?

Answer 61

Vitamin B2 (riboflavin) deficiency

Question 62

Pellagra sx? Vitamin defect?

Answer 62

``` 3 D's: Diarrhea, Dermatitis, Dementia Vit B3 (niacin) deficiency ```

Question 63

Branches of thyrocervical trunk?

Answer 63

Inf thyroid artery Superficial cervical artery Suprascapular artery (it's a trunk off of subclavian artery)

Question 64

What does recurrent laryngeal nerve loop around on the left and the right?

Answer 64

``` R = subclavian arter (between the subclavian vein and artery) L = arch of aorta ```

Question 65

What 5 cytokines recruit neutrophils?

Answer 65

IL-8 (secreted by macrophages), leukotriene B4 and 5-HETE, C5a, n-formylated peptides

Question 66

What does C3a do?

Answer 66

Recruits eosinophils and basophils | Also stimulates mast cell histamine release

Question 67

What does C5a recruit?

Answer 67

Eosinophils Basophils Neutrophils Monocytes

Question 68

Capillary hemangioblastoma in the retina/cerebellum + pheochromocytoma + clear cell renal carcinoma + cysts of kidney, liver, and/or pancreas. What's the disease?

Answer 68

VHL | Could be tuberous sclerosis if it's cortical/subependymal HAMARTOMAS

Question 69

Cortical/subependymal hamartomas + cysts of kidney, liver, and/or pancreas + cardiac rhabdomyosarcoma + adenoma sebaceum (cutaneous angiofibroma) + renal angiomyolipoma + ash-leaf skin patches. What's the disease?

Answer 69

Tuberous sclerosis | Seizure is the major complication

Question 70

Congenital telangiectasias (creating epistaxis, GI bleed, hematuria). What's the disease?

Answer 70

Osler-Weber-Rendu syndrome (AD hereditary hemorrhagic telangiectasia)

Question 71

Cutaneous facial angiomas (facial port-wine stain) + leptomeningeal angioma (capillary venous malformation) + V1&V2 skin involvement + tram-track calcification of skull. What's the disease?

Answer 71

Sturge-Weber syndrome (encephalotrigeminal angiomatosis)

Question 72

Exquisite ear pain and drainage + granulation tissue w/in ear canal + intact tympanic membrane. What's the causal org? What pt population?

Answer 72

``` Pseudomonas aeruginosa (motile, oxidase positive G- rod) This condition is called malignant otitis externa (MOE) - contrast this to acute otitis media, which affects tympanic membrane and is caused by H influenzae Pt population: elderly diabetics ```

Question 73

Inflamed, bulging, erymathous, nonmotile tympanic membrane + infected fluid in middle ear. What's the causal org? What pt population?

Answer 73

H. influenzae This condition is called acute otitis media, contrast to malignant otitis externa, which doesn't affect tympanic membrane Pt population: kids and adults

Question 74

Athralgia + brown spots on sclerae + diffuse darkening of helix of ears. What's the disorder and enzyme defect?

Answer 74

Alkaptonuria (most characteristic thing is urine turns black when exposed to room air - bc homogentisic acid is oxidized) Homogentisate oxidase

Question 75

In elevator with a bunch of people, hospitalist asked if you got a brain CT result on pt in room 200. What do you do?

Answer 75

"Let's step off the elevator and discuss it" CANT acknowledge that the pt had a brain scan ("I have the results and can call you later" or "The scan was read, ask the resident on duty for the results") and DONT admonish colleague in the elevator

Question 76

What AA is used to make serotonin?

Answer 76

Tryptophan

Question 77

What 5 molecules is tyrosine a precursor of?

Answer 77

``` Dopamine NE Epinephrine Thyroxine Melanin ```

Question 78

What 4 molecules is methionine a precursor/intermediate of?

Answer 78

Cysteine Carnitine Taurine Lecithin

Question 79

3 ways Aspergillus messes stuff up and pt population for each category

Answer 79

1) Invasive aspergillosis: hemoptysis, pleuritic chest pain & fever, necrotizing pneumonia, granuloma -> those w/ immunocompromised, neutropenia, and chronic granulomatous disease are susceptible 2) Allergic bronchopulmonary aspergillosis (ABPA): bronchiectasis, eosinophilia, migratory pulm infiltrates, increased IgE and Ab -> those w/ asthma and CF are susceptible 3) Aspergillomas: seen on CXR as radiopaque structure that shifts when pt changes position, colonizing existing lung cavities (such as after TB), can cause hemoptysis

Question 80

What do you call T cells that are negative for both CD4 and CD8?

Answer 80

Pro-T cells

Question 81

What do you call T cells that are positive for both CD4 and CD8?

Answer 81

Immature T lymphocyte

Question 82

Where does positive selection of T cells occur and what cells does it need?

Answer 82

Positive selection: cells that binds to self MHC are allowed to SURVIVE Thymic cortex Needs thymic epithelial cells

Question 83

Where does negative selection of T cells occur and what cells does it need?

Answer 83

Negative selection: cells that bind w/ high affinity to self Ag DIE Thymic medulla Needs thymic medullary epithelial cells and dendritic cells

Question 84

Differences between macrophages and B cells in terms of Ag presentation

Answer 84

Macrophages: inducably express MHCII and B7; can only stimulate effector or memory T cells, not naive T cells B cells: constitutively express MHCII, can stimulate all types of T cells

Question 85

Heterophile Ab positive. What's the org?

Answer 85

EBV | "monospot test"

Question 86

5 diseases assc. w/ EBV?

Answer 86

``` Hodgkin lymphoma Burkitt lymphoma (endemic, African type) Nasopharyngeal lymphoma (Chinese) CNS lymphoma (AIDs pts) Post-transplant lymphoproliferative disorder ```

Question 87

See increased MMP activity + fibroblasts in wound 3 weeks out. What's the related possible complication?

Answer 87

Contracture

Question 88

What is t-test used for?

Answer 88

Differences bet. MEANS of 2 groups

Question 89

What is ANOVA (analysis of variance) used for?

Answer 89

Differences bet. MEANS of 3 or more groups

Question 90

What is chi-square used for?

Answer 90

Difference bet. 2 or 3 percentages or proportions of CATEGORICAL outcomes (not mean values)

Question 91

What is Pearson correlation coefficient? And what does this tell you exactly?

Answer 91

r value in linear correlation (always between -1 and +1) | Tells you how well the data fit to the linear regression -> NO RELATION to magnitude of slope

Question 92

What is coefficient of determination?

Answer 92

r^2 (Pearson correlation coefficient squared) -> value that's usually reported

Question 93

HIV pt came in w/ CMV retinitis. Treated and is now having generalized seizure, hypocalcemia, hypomagnesemia. What was the drug? And why was that drug used over other CMV drugs?

Answer 93

Foscarnet (Ca2+ chelation -> renal wasting of magnesium -> hypomagnesemia -> decreased PTH -> even lower Ca2+ -> seizure) Prefer foscarnet over the usual ganciclovir in CMV retinitis assc. w/ HIV b/c HIV pts are usually on zidovudine which causes bone marrow suppression. Ganciclovir causes severe neutropenia that can worsen that.

Question 94

Mom and daughter are incapacitated and need blood transfusion. Called father and he said they're Jehova's witnesses. Father hung up before physician can ask about giving blood product, and mom and daughter are not carrying a card that confirms religious belief. What do you do?

Answer 94

Give blood to both mom and daughter Mom: would have had the rights to refuse life-saving treatment had she not been incapacitated, but she is and next of kin surrogate decision maker (husband) can't be reached. So can give blood to her Daughter: always give life-saving therapy in emergency situations regardless of parents' wishes

Question 95

Th1 (stimulation, secretion & fx, inhibition)

Answer 95

Stimulated by: IL-12 (from macrophages) Secretion: IFN-g and IL-2 -> activates macrophages and CD8 T cells Inhibited by: IL-4, IL-10 (from Th2)

Question 96

Th2 (stimulation, secretion & fx, inhibition)

Answer 96

Stimulated by: IL-4, IL-10 Secretion: IL-4, IL-5, IL-6, IL-13 -> recriots eosinophils and promotes IgE production Inhibited by: IFN-g (from Th1)

Question 97

IL-1 (origin and 2 fx)

Answer 97

Secreted by: macrophages Fx: osteoclast-activating factor, fever & acute inflammation (activates endothelium to express adhesion molec, recruits leukocytes by inducing chemokine secretion)

Question 98

IL-6 (2 origins and fx)

Answer 98

Secreted by: macrophages, Th2 | Fx: fever (stimulate production of acute-phase protein)

Question 99

IL-8 (origin and fx)

Answer 99

Secreted by: macrophages | Fx: chemotactic factor for neutrophils

Question 100

IL-12 (2 origins and 2 fx)

Answer 100

Secreted by: macrophages, B cells | Fx: differentiation of T cells into Th1, activates NK

Question 101

TNF-a (origin, 2 fx, disease assc.)

Answer 101

Secreted by: macrophages Fx: septic shock, activates endothelium (leukocyte recruitment and vascular leak), mediates paraneoplastic cachexia (by suppressing appetite in hypothalamus, inhibiting lipoprotein lipase, and increasing insulin resistance in peripheral tissues) Disease assc: RA, psoriatic arthritis, TB

Question 102

IL-2 (origin and fx)

Answer 102

Secreted by: EXCLUSIVELY lymphocytes -> secreted by all T cells (so deficiency in IL-2 RECEPTOR -> SCID) -> first thing T cells produce after coming in contact w/ Ag Fx: growth&differentiaion of T cells, B cells, NK, and macrophages

Question 103

IL-3 (origin and fx)

Answer 103

Secreted by: all T cells Fx: growth & differentiation of bone marrow stem cells (fx like GM-CSF tha's produced by all kinds of cells -> macrophages, T cells, NK, mast cells, endothlial cells, fibroblasts)

Question 104

IFN-g (origin and 3 fx)

Answer 104

Secreted by: Th1 Fx: activates macrophages, antiviral (activates NK), antitumor, increases MHC expression and Ag presentation in all cells

Question 105

IL-4 (origin and 3 fx)

Answer 105

``` Secreted by: Th2 Fx: Th2 differentiation, B cell growth, class switching to IgE and IgG ```

Question 106

IL-5 (origin and 3 fx)

Answer 106

``` Secreted by: Th2 Fx: B cell differentiation, class switching to IgA, growth & differentiation of neutrophils, growth&differentiation of neutrophils ```

Question 107

IL-10 (2 origins and fx)

Answer 107

Secreted by: Th2, regulatory T cells Fx: downregulates inflammatory responses, inhibits activated T cells and Th1 (similar actions to TGF-B b/c anti-inflammatory)

Question 108

What's the most common cause of pseudotumor cerebri in teenagers?

Answer 108

Tetracycline (for acne)

Question 109

What system do you see cGMP-gated Na+ channels?

Answer 109

Vision

Question 110

B1 receptor effector & organ system

Answer 110

Gs -> increases cAMP Heart, kidney (renin release) Lipolysis

Question 111

B2 receptor effector & organ system

Answer 111

Gs -> increases cAMP Lungs, insulin release, decreases uterine tone, relaxes CILIARY MUSCLE (thins lens to focus on distant vision), increases aq humor production Vasodilation, lipolysis, heart (increases HR)

Question 112

a1 receptor effector & organ system

Answer 112

Gq -> increases IP3 | Vasocontriction, contracts PUPILARY MUSCLE (MYDRIASIS), contracts intestinal and bladder sphincter

Question 113

a2 receptor effector & organ system

Answer 113

Gi -> decreases cAMP Increases platelet aggregation Decreases sympa outflow, insulin release, lipolysis

Question 114

M1 receptor effector & organ system

Answer 114

Gq -> increases IP3 | CNS & ENS

Question 115

M2 receptor effector & organ system

Answer 115

Gi -> decreases cAMP | Heart (decreases HR and contraction)

Question 116

M3 receptor effector & organ system

Answer 116

Gq -> increases IP3 All other things besides heart and CNS&ENS -> secretions (incl insulin!), gut motility, bladder, bronchoconstriction, Contracts CILIARY MUSCLE (so effect opposite of B2) (makes lens round to focus on near vision -> accommodation)

Question 117

D1 receptor effector & organ system

Answer 117

Gs -> increases cAMP | Renal vascular smooth muscle (relaxes)

Question 118

D2 receptor effector & organ system

Answer 118

Gi -> decreases cAMP | Modulates transmitter release

Question 119

H1 receptor effector & organ system

Answer 119

Gq -> increases IP3 | Nasal&bronchial mucus, vascular permeability, pruritus, pain, bronchiole contraction

Question 120

H2 receptor effector & organ system

Answer 120

Gs -> increases cAMP | gastric secretion

Question 121

V1 receptor effector & organ system

Answer 121

Gq -> increases IP3 | Increases vascular smooth muscle contraction

Question 122

V2 receptor effector & organ system

Answer 122

Gs -> increases cAMP | Increases H2O permeability in kidney

Question 123

5 things that Down pts are more at risk for

Answer 123

Leukemia (AML - acute megakaryoblastic leukemia subtype before 5 yo, ALL after 5 yo) Congenital heart defects (esp VSD & endocardial cushion defects -> ostium primum ASD, regurgitant AV valves from cleft in ant leaflet of mitral or septal leaflet of tricuspid) Duodenal atresia (NOT other segments) Hirshsprung disease Early onset Alzheimer

Question 124

Differences in immune response when using killed viral vaccine and live attenuated viral vaccine?

Answer 124

Killed viral vaccine: humoral immune response -> Ab generated to neutralize virus and prevent it from ENTERING cells (killed virus can't actually infect host cells) Live-attenuated viral vaccine: virus actually enters cells and stimulates MHC I pathway -> CD8+ cells kill infected cells in future exposures

Question 125

What age should ppl start being vaccinated w/ flu vaccine?

Answer 125

> 6 mo

Question 126

What do interferon a and b do specifically?

Answer 126

Suppressing viral REPLICATION and ASSEMBLY

Question 127

Cause of wrinkles?

Answer 127

Decreased collagen SYNTHESIS and elastin Thinning of dermis & epidermis + flattening of dermoepidermal jx Decreased # of fibroblasts NOT decreased proline hydroxylation or collagen cross-linking, etc

Question 128

What's capitation?

Answer 128

Physician is paid fixed amount per enrollee. So there's incentives to providing preventive care. Commonly used by HMOs (as opposed to fee-for-service or discounted fee-for-service, which is used in preferred provider organization type)

Question 129

How is botulinum toxin released? How do you dx?

Answer 129

It's contained inside cell and released w/ autolysis (so NOT actively secreted) Detecting toxin in stool (ELISA and PCR)

Question 130

3 D's of botulinum toxin poisoning

Answer 130

Dysphagia Diplopia Dysphonia In 12-46 hrs

Question 131

Lacks multiple enzymes containing lipoic acid subunit. Most likely finding?

Answer 131

Need this as cofactor for pyruvate DH, alpha ketoglutarate DH, and alpha ketoacid DH So most important finding would be lactic acidosis, because you don't have pyruvate DH to bridge glycolysis to TCA, so pyruvate gets shunted to make lactate instead

Question 132

Yeast and pseudohyphae on LM + positive germ tube test?

Answer 132

Candida albican (germ tube test used to differentiate it from other Candidas)

Question 133

What does cutaneous candidiasis look like?

Answer 133

Erythema, vesiculopapular rash, maceration, fissuring

Question 134

Oval yeast cells w/in macrophages. Caseating granulomas in tissues. What fungus?

Answer 134

Histoplasmosis

Question 135

Bird or bat droppings. What fungus?

Answer 135

Histoplasmosis

Question 136

Broad-base budding + thick, doubly refractive walls?

Answer 136

Blastomycosis

Question 137

The incidence of what fungal infection goes up after earthquake?

Answer 137

Coccidioidomycosis

Question 138

Spherule filled w/ endospores found in granulomas?

Answer 138

Coccidioidomycosis

Question 139

Budding yeast w/ captain's wheel formation + Latin America

Answer 139

Paracoccidioidomycosis

Question 140

Irregular, broad, nonseptate hyphae branching at wide angles?

Answer 140

Mucor

Question 141

Disc-shaped yeast on methenamine silver stain?

Answer 141

Pneumocystis jirovecii (PCP)

Question 142

Dimorphic, cigar-shaped budding yeast living on vegetation?

Answer 142

Sporothrix schenckii

Question 143

Rose gardener's disease. What fungus?

Answer 143

Sporothrix schenckii

Question 144

Most common causes of hepatic abscesses in developed countries? Developing countries?

Answer 144

Developed countries -> consider bacterial Hematogenous: S. aureus Ascending cholangitis/portal vein pyemia/direct invasion from adjacent area: E. coli, Klebsiella, enterococci Developing countries -> consider parasites Entamoeba (ascending from the colon thru portal venous system), echinococcal

Question 145

Acute transplant rejection timeline and histology?

Answer 145

Timeline: w/in 6 months Histology: either cell-mediated or Ab-mediated -> so see lymphocyte infiltration

Question 146

Conditions assc w/ low or high AFP during pregnancy

Answer 146

High AFP: omphalocele, multiple gestation, body wall defect (gastrochisis), neural tube defect Low AFP: Down -> do amniotic karyotyping for definitive dx next

Question 147

Percentage values for 1SD? 2SD? 3SD?

Answer 147

1SD: 68% 2SD: 95% 3SD: 99.7%

Question 148

Infection w/ what group of orgs should be assc. w/ "impaired intracellular killing"

Answer 148

Catalase-positive stuff -> so staph | Impaired cellular killing -> chronic granulomatous disease -> recurrent cutaneous abscesses

Question 149

Why is having too much IgA put you at risk for disseminated N. meningitidis infection?

Answer 149

IgA binds to bac and prevents them from attaching to mucosal surface, but doesn't activate complement killing like IgM and IgG do -> complement activation is a more effective form of killing b/c it's actually bacteriocidal

Question 150

Start and stop codons?

Answer 150

Start: AUG -> methionine Stop: UAA, UAG, UGA -> "releasing factor" recognizes these codons Read mRNA from its 5' -> 3'

Question 151

What does elongation factor do?

Answer 151

Facilitates tRNA binding and translocation steps of protein synthesis

Question 152

What does transcription factor II D do?

Answer 152

Binds TATA promoter region upstream from the gene's coding region

Question 153

Patient w/ signs of domestic violence who is in denial ("I'm sure it won't happen again"). What should you say?

Answer 153

"Do you have a safe place to go in an emergency?" The focus should be to ask open-ended, nonjudgmental questions, and to assess immediate and future safety. DONT counsel patients in directive way or ask why she stays in a relationship

Question 154

Describe histologic characteristics of koilocytes (besides resinoid appearance)

Answer 154

Immature squamous cell w/ enlarged pyknotic nucleus, irregularly staining cyto, and perinuclear vacuoles (PERINUCLEAR CLEARING)

Question 155

Pap smears show predominance of parabasal cells. What does this mean and what do parabasal cells look like?

Answer 155

Means it's from post-menopausal and post-partum women | They're round cells w/ BASOPHILIC cyto, finely granular chromatin in nuclei, high N/C ratio

Question 156

Normal glandular endocervical cells on Pap smear. What does this mean and what do normal glandular cells look like?

Answer 156

Indicates ADEQUATE sampling They're columnar cells w/ vacuolated/granular cytoplasm, prominent cell border -> forming HONEYCOMB pattern when clustered together

Question 157

2 other names for alpha toxin from C. perfringens? What does it do?

Answer 157

Lecithinase, phospholipase C Loss of cell membrane integrity -> increases platelet aggregation and adherence molecule expression (on leukocytes and endothelium) -> vasoocclusion & ischemic necrosis of tissues

Question 158

What 4 things does pertussis toxin (AB toxin) do?

Answer 158

Inhibits Gi (by ribosylating it) so increases cAMP -> get Massive lymphocytosis (chemokines disabled) -> so lymphocytes can't come to tissues -> same as lymphocyte destruction?? Neutrophil destruction Insulin release Increased sensitivity to histamine

Question 159

Mechanism behind rheumatic fever? (brief)

Answer 159

Autoimmune activation by antigen mimicry (GAS and myocytes have similar antigenic protein sequences)

Question 160

Example of X-linked dominant disease?

Answer 160

Hypophosphatemic rickets -> phosphate wasting at proximal tubule "vit-D-resistant rickets"

Question 161

3 examples of mitochondrial inheritance pattern?

Answer 161

Myoclonic epilepsy w/ ragged red fibers (MERRF): from failure in oxidative phosphorylation (myopathy + lactic acidosis + CNS disease) Leber hereditary optic neuropathy Mitochondrial encephalopathy w/ stroke-like episodes and lactic acidosis (MELAS)

Question 162

Pt's serum is mixed w/ solution of cardiolipin, lecithin, and cholesterol and flocculation is considered positive test. What test is this called and what would it be positive for?

Answer 162

RPR test (VDRL) for syphilis -> screening test so needs confirming by FTA-ABS

Question 163

Pt's blood is added to tube pretreated w/ anticoagulant (EDTA) and tube is placed in a cup of ice. Agglutination is considered positive. What test is this called and what would it be positive for?

Answer 163

Cold agglutinins for Mycoplasma, EBV, hematologic malignancies

Question 164

What's one way to deplete carnitine and impair beta-oxidation of FA?

Answer 164

Excessive alcohol consumption

Question 165

S. aureus cultured from urine. What should you suspect?

Answer 165

S. aureus doesn't usually cause UTI, so suspect metastatic infection from other sites such as abscesses or infective endocarditis

Question 166

What to say when pt wants antibiotics for viral illness?

Answer 166

Don't prescribe b/c of potential risks of drug (and antibiotic resistance problem)

Question 167

What are the fx of 2 diphtheria toxins? Which one induces immune response?

Answer 167

Exotoxin B: binds specifically to heparin-binding EGFR on cardiac and neural cells (selectivity) and allow penetration of A subunit -> production of circulating IgG is against this subunit A subunit: active subunit that ribosylates ADP of EF-2 and inhibits protein synthesis

Question 168

3 disorders of myopathies w/ elevated creatine kinase? 2 disorders w/ normal creatine kinase?

Answer 168

Myopathies w/ elevated creatine kinase: inflammatory myopathies (polymyositis, dermamyositis), statin-induced myopathy, hypothyroid myopathy (myoedema characteristic) Myopathies w/ normal creatine kinase: glucocorticoid-induced myopathy (weakness/atrophy w/out pain), polymyalgia rheumatica (pain&stiffness worse in morning & w/ activity)

Question 169

4 virulence factors produced by P. aeruginosa

Answer 169

Exotoxin A: protein synthesis inhibition Elastase: for vessel destruction Phospholipase C: degrades cellular membranes Pyocyanin: generates reactive oxygen species -> kill competing microbes

Question 170

What is Klebsiella usually assc. w/ in elderly and immunocompromised?

Answer 170

Necrotizing pneumonia

Question 171

When should advance directives be discussed and what are their 2 main components?

Answer 171

Ideally in outpatient setting w/ primary care, but ESPECIALLY when pt is hospitalized (get over the awkwardness) Components: living will and health care proxy

Question 172

3 basic AAs?

Answer 172

"His Arguments are based on Lies" | Histidine (no charge at body pH), Arginine, Lysine

Question 173

How do you calculate charges on AA?

Answer 173

At pH above pKa, proton dissociates from AA -> so carboxyl group and ammonium groups exist as COO- and NH2 So pH below pKa, they exist as COOH, NH3+

Question 174

What is MacConkey agar and what orgs does it restrict?

Answer 174

Bilt salt-containing agar Restricts growth of most G+ Colony turns pink-red if ferments lactose

Question 175

2 other names for Thayer-Martin VCN medium?

Answer 175

Heated blood agar | Chocolate agar

Question 176

What is Bordet-Gengou medium used to grow?

Answer 176

Bordetella pertussis

Question 177

What fungal infections are assc. w/ recent antibiotic use?

Answer 177

Superficial Candida (oral thrush or vulvovaginitis)

Question 178

What fungal infections are assc. w/ animal contact?

Answer 178

Dermatophytoses caused by Microsporum species (tinea capitis)

Question 179

Describe lesions caused by Sporothrix? Histology?

Answer 179

Reddish nodule that later ulcerates -> fungus spreads along lymphatics forming subQ nodules and ulcers Granuloma consisting of histiocytes + giant cells + neutrophils, surrounded by plasma cells

Question 180

What Ig bind complement and what specific region binds to it?

Answer 180

IgM and IgG -> IgM is better at it b/c it circulates in pentameric form (monomeric for IgG) -> good b/c C1 needs 2 Ig domains for activation C1 binds to Fc region NEAR THE HINGE POINT (the farther carboxyl region is for Fc receptor on phagocytes, and for J chain that join multiple IgA or IgM together so they cancirculate in dimeric or pentameric form) -> so complement activation by IgM before Ag binding is prevented form happening by the fact that this region is hidden while unbound IgM is circulating in its planar form

Question 181

3 cytogenetic abnormalities that can lead to Down

Answer 181

1. Trisomy 21 (meiotic nondisjunction IN OVUM) 2. Unbalanced Robertsonian translocation (extra arm of 21 is attached to another chromosome) -> so have normal # of chromosomes 3. Mosaicism

Question 182

3 genetic syndromes caused by deletions?

Answer 182

Cri du chat (5p) Prader-Willi (15q) Angelman (15q)

Question 183

What is impaired in hyper-IgM syndrome?

Answer 183

Immunoglobin gene rearrangement

Question 184

Loss of follow up occurs disproportionately bet. the exposed and unexposed group. What bias might occur?

Answer 184

``` Attrition bias (type of selection bias) Does NOT occur if loss of follow up happens proportionately to both groups ```

Question 185

Sx of pyridoxine (B6) deficiency? What 2 drugs can induce this?

Answer 185

Peripheral neuropathy, convulsion, dermatitis, sideroblastic anemia (need this to synthesize Hb), iron excess Drugs that induce: INH, OCPs

Question 186

Bacterial ribosomal components and their fx?

Answer 186

30S ribosomal subunit: has 16S rRNA -> holds sequence complementary to Shine Dalgarno sequence (present in all prokaryotic cells and is upstream from AUG sequence) -> necessary for protein translation initiation 50S ribosomal subunit: has 23S rRNA -> peptidyltransferase activity Elongation factor G: translocation of protein, energy supplied by GTP A site: binds incoming aminoacyl-tRNA

Question 187

Where is aminoacyl-tRNA synthetase in the cell?

Answer 187

Cytosol, each specific for particular AA/tRNA pair

Question 188

Formula for calculating HL from VD and Cl? How many HL does it take to virtually eliminate a drug?

Answer 188

t1/2 = 0.7 x VD/CL VD = vol of distribution Cl = clearance Takes about 5 HLs to virtually eliminate a drug/establish SS conc

Question 189

What agar do you use to grow V cholerae?

Answer 189

TCBS agar -> very alkaline selective media

Question 190

What does a vaccine for V cholerae stimulate and what kind of vaccine is it?

Answer 190

``` Secretory IgA Killed bacteria (same as Yersinia pestis vaccine) ```

Question 191

What vibrio orgs are ppl w/ chronic liver disease susceptible to?

Answer 191

V. vulnifics from wound infection, but can also get from oyster NO person-to-person

Question 192

Difference between effect modification and confounding bias?

Answer 192

``` Stratified analysis (analyze cohort as a diff subgroup) will show statistical significance in effect modification, but not in confounding bias Effect modification is NOT a bias but a natural phenomenon ```

Question 193

7 AAs w/ 3 titratable protons?

Answer 193

HALGACT | Histidine, arginine, lysine, glutamate, aspartate, cysteine, tyrosine

Question 194

Features of Patau?

Answer 194

Characteristic midline stuff (Patau for "Parting"): cleft lip/palate, holoprosencephaly, coloboma, abdominal wall defects Other stuff: POLYDACTYLY, polycystic kidney disease, rocker bottom feet (see this in Edwards too), umbilical hernia, pyloric stenosis

Question 195

Features of Edwards?

Answer 195

Clenched hand w/ index finger overriding middle finger, and 5th finger overriding 4th finger, Meckel's diverticulum, malrotation, prominent occiput, low-set ears, rocker bottom feet (see this in Patau too)

Question 196

How could you tell SCID apart from other congenital immune stuff?

Answer 196

Will have infection susceptibility characteristics of both T cell and B cell deficiencies -> so you get recurrent infections by bac, fungi, virus, OPPORTUNISTIC PATHOGENS -> failure to thrive and chronic diarrhea w/in 1st year of life Infections characteristics of B cell deficiencies: extracel encapsulated bac (H. influenzae, Strep pneumo, Moraxella) Infections characteristics of T cell deficiencies: Pneumocystis, chronic mucocutaneous candidiasis, toxo, crypto

Question 197

Older pt starts addressing intern w/ first name b/c intern looks like her grandson, so intern starts addressing her b first name. What should an attending do?

Answer 197

Address the pt w/ Mr./Mrs. followed by last name DON'T even ask if it's ok to start addressing her by first name (pt should always be the one to initiate lowering level of formality, not doctor)

Question 198

What accounts for antiseptic properties of alcohols? Does it kill bacterial spores?

Answer 198

Disrupting cell membrane + denatures proteins | Doesn't kill spores

Question 199

What accounts for antiseptic properties of chlorhexidine? Does it kill bacterial spores?

Answer 199

Disrupting cell membrane + coagulation of cytoplasm Doesn't kill spores Neurotoxic so don't use w/ eyes, ears, neurological procedures

Question 200

What accounts for antiseptic properties of H2O2? Does it kill bacterial spores?

Answer 200

Free radicals | Kills spores

Question 201

What accounts for antiseptic properties of iodine? Does it kill bacterial spores?

Answer 201

Halogenation of proteins and nucleic acids | Kills spores

Question 202

What accounts for antiseptic properties of aldehydes?

Answer 202

Alkylating and X-linking DNA and proteins

Question 203

Endocarditis by what 2 groups of bac is assc. w/ dental extraction?

Answer 203

Viridans group strep (on ALREADY ABNORMAL heart valves) | HACEK organisms

Question 204

Dx of skin hyperextensibility + joints hypermobility + poor wound healing + easy bruising?

Answer 204

Ehlers-Danlos

Question 205

What are TATA and CAAT boxes considered? Where are they in the gene?

Answer 205

PROMOTER REGION (initiates transcription by serving as binding sites for transcription factors and RNA pol II) TATA: 25 nucleotides upstream CAAT: 70-80 bases upstream

Question 206

Where does nitrogen source in urea cycle come from?

Answer 206

NH3 and ASPARTATE

Question 207

What's the fx of glutamine?

Answer 207

Transports ammonia from peripheral tissue to kidney -> in the nephron glutaminase cleaves it and generates glutamate + NH4+ (which is then excreted in urine)

Question 208

Molecules involved in neutrophil rolling? Tight adhesion/crawling? Transmigration?

Answer 208

Rolling: Sialyl Lewis X (PSGL-1) to L-selectin (on neutrophils) or E-selectin/P-selectin (on endothelium) Tight adhesion/crawling: CD18 beta 2 integrins (Mac-1 and LFA-1) to ICAM-1 (endothelium) Transmigration: PECAM-1

Question 209

Pt's family shows up during emergency situation (pt had MI and in OR) and ask how the pt is doing. They don't have ID's. Do you tell them?

Answer 209

Yes, HIPAA doesn't require ID. You don't need explicit permission in the case where pt is present and doesn't object, and in the case that the pt can't be present but sharing would be in pt's best interest -> only share general details tho

Question 210

What 2 vitamins do you need to give infants who are exclusively breastfeed?

Answer 210

Vit K: usually given at birth Vit D: b/c infants are usually shielded from the sun and it's not in breast milk Iron is present in breast milk so don't need that

Question 211

What is cholera toxin most related to?

Answer 211

Enterotoxigenic E. coli heat labile toxin

Question 212

What orgs should you suspect if poop has mucus + sloughed epithelial cells? Many erythrocytes and some leukocytes or w/ neutrophilic predominance? Erythrocytes w/out leukocytes? Many leukocytes w/ eosinophil predominance? Many leukocytes w/ monocytic predominance?

Answer 212

Mucus + sloughed epithelial cells: V. cholera, Enterotoxigenic E. coli, Giardia Many erythrocytes and some leukocytes or w/ neutrophilic predominance: Shigella, Salmonella, C jejuni, EIEC (enteroinvasive E. coli), Entamoeba Erythrocytes w/out leukocytes: E. coli O157:H7 Many leukocytes w/ eosinophil predominance (Charcot-Leyden crystals): parasites besides Entamoeba and Giardia Many leukocytes w/ monocytic predominance: Salmonella typhi

Question 213

What 3 extracellular things does integrin react w/?

Answer 213

Fibronectin (also binds to GAG, matrix collagen) Collagen Laminin (binds IV collagen = BM)

Question 214

What does heparan sulfate do?

Answer 214

Mediates endothelial cell attachment to BM

Question 215

What does keratan sulfate do?

Answer 215

Maintains type I collagen fibril organization in cornea

Question 216

Keloid vs. hypertrophic scar? Does primary intention healing reduce the risk of developing keloid?

Answer 216

Hypertrophic scar is limited to the area of the wound and may regress spontaneously, and the collagen fibers are arranged in parallel (as opposed to disorganized like keloid) No, primary intention healing is just as likely as any other wound to lead to keloid

Question 217

What is southern blotting used for? Northen blot? Western blot? Southwestern blot?

Answer 217

Southern: DNA -> Identify DNA mutation (use labeled DNA probe to bind to DNA samples) Northern: mRNA Western: protein Southwestern: TF (DNA-bound protein)

Question 218

What does brown adipocytes do? What are the differences between them and white adipocytes?

Answer 218

Thermal regulation in neonates (the oxidative phosphorylation is uncoupled w/ the protein thermogenin in these cells so instead of generating ATP in mito, they generate heat instead) Compared to white adipocytes, brown adipocytes have more fat droplets and more mitochondria

Question 219

What's the best approach in dealing w/ pt w/ somatic sx disorder (sick despite ruling out all biological possibilities)?

Answer 219

Increase frequency of regularly scheduled visits w/ primary care provider -> focus on functional improvement rather than sx elimination

Question 220

A test w/ 95% specificity. How do you calculate the probability of having at least 1 positive result if you were to perform this test on 8 pts?

Answer 220

Probability of all 8 pts having negative results: 0.95^8 Probability of having AT LEAST ONE positive results: 1 - (0.95^8) Always use this method whenever asked for probability of AT LEAST ONE event happening (calculate the opposite event first and subtract it from 1)

Question 221

What role do pili play in the infection by N. meningococci?

Answer 221

Help them adhere to nasopharynx, oropharynx | Help them cross BBB

Question 222

In what situation do you get non-immune mediated mast cell degranulation?

Answer 222

Opiates, vancomycin -> pseudoallergic rxn b/c doesn't involve drug-specific IgE

Question 223

What measurement value is resistant to outliers?

Answer 223

Mode | mean, median, range, SD, variance are usually all affected by outliers

Question 224

How do you calculate incidence?

Answer 224

``` # of new cases/# of ppl at risk the # of ppl at risk has to be after subtracting # of ppl already w/ the disease Example: disease A has 7,000 new cases this year. population is 4 mil, which contains 20,000 ppl already w/ disease A. Incidence is 7,000/3,980,000 ```

Question 225

How do you calculate disease specific mortality?

Answer 225

of death attributable to a particular disease per year divided by TOTAL POPULATION (incl ppl already living w/ disease)

Question 226

How do you calculate the rate of increase of a disease?

Answer 226

New cases per year - # of deaths or cures per year, divided by TOTAL POPULATION (incl ppl already living w/ disease)

Question 227

80 yo w/ "mild cognitive impairment" brought in by her son and you suspect elderly abuse. What do you do?

Answer 227

Ask son to leave and ask pts additional question (assume cognitively impaired adults can communicate useful info)

Question 228

3 bacteria whose polysaccharide capsules are conjugated to protein carriers as vaccines?

Answer 228

N. meningitidis: conjugated to mutant nontoxic diphtheria toxoid H. influenzae: conjugated to N. meningitidis outer membrane protein complex Strep pneumo: children PCV13 one is conjugated to inactivated diphtheria toxin (adult PPSV23 contains just capsular material) Conjugation is to stimulate T-mediated Ig class switching and memory B cell generation (wouldn't get that w/ pure polysaccharide)

Question 229

What form does tetanus vaccine comes in?

Answer 229

Tetanus toxoid (inactivated toxin, not conjugated)

Question 230

What form does pertussis vaccine comes in?

Answer 230

Purified component of the bacteria + detoxified pertussis toxoid

Question 231

What form does HBV vaccine comes in?

Answer 231

Purified inactivated HBsAg particles -> "recombinant surface protein vaccine" -> drawbacks similar to killed vaccine

Question 232

What form does BCG vaccine comes in?

Answer 232

Live-attenuated vaccine from Mycobacterium bovis

Question 233

UTI w/ acute onset dysuria and hematuria that resolves spontaneously w/in 3 days. Org?

Answer 233

Adenovirus Sx described is called hemorrhagic cystitis -> adenovirus is the most common viral cause of this in children (serotypes 11 and 21 of subgroup B)

Question 234

Differences bet. Norwalk and Rotavirus?

Answer 234

Norwalk (calicivirus): epidemics of viral gastroenteritis worldwide Rotavirus: most common cause of fatal diarrhea in children, esp in winter

Question 235

Characteristics of hyperacute rejection vs. acute rejection vs. chronic rejection?

Answer 235

``` Hyperacute rejection: blood flow stops immediately after anastomosis of vessels (mediated by PREFORMED Ab), might also see vascular fibrinoid necrosis and neutrophil infiltration Acute rejection (1-4 wks post transplant): host T cells are sensitized against graft MHC Ag -> immunosuppressive drugs target this phase; in lungs pulm & bronchial vessels are main targets Chronic rejection (months-years): vascular stuff if kidney (scant inflammatory cells, interstitial fibrosis, fibrous intimal thickening of vessels -> mediated by host T cells + B cells + Ab); inflammation of small bronchioles if lung (bronchiolitis obliterans) ```

Question 236

How does non-pathogenic Corynebacterium acquire virulence?

Answer 236

Lysogenization by a temperate bacteriophage -> Tox gene transferred -> can now cause pseudomembranous pharyngitis

Question 237

What's lanugo? What condition is this seen in?

Answer 237

Fine, pale, dawny hair | Seen in anorexia

Question 238

Non-lactose fermenting G- rods infecting indwelling bladder catheter?

Answer 238

P. aeruginosa (opportunistic)

Question 239

Dx of kind w/ short stature + hypotonia + obesity + intellectual disability?

Answer 239

Prader-Willi syndrome -> maternal imprinting (paternal gene deleted) Chr 15

Question 240

Dx of happy kid w/ seizures + ataxia + severe intellectual disability?

Answer 240

Angelman syndrome -> paternal imprinting (maternal gene deleted) Chr 15

Question 241

How does mucormycosis present and what is the assc. condition?

Answer 241

Affects paranasal sinus so present w/ facial/periorbital, pain, headache, purulent nasal discharge, black eschar (necrotic tissue) on palate or nasal turbinates See org branching at 90 degree angle Strongly assc. w/ diabetic ketoacidosis, immunosuppression

Question 242

Nutritional deficiency that can result in dilated cardiomyopathy?

Answer 242

Thaimine deficiency (wet beri beri)

Question 243

Where is intermediate jx and what does it mediate?

Answer 243

Below tight jx in epithelial cells | Mediates cell-cell adhesion

Question 244

How do most enveloped nucleocapsid viruses obtain their lipid bilayer? And what group of virus is the exception?

Answer 244

``` Most viruses (incl HCV, mumps): acquire from host PLASMA membrane Exception is herpesvirus (incl CMV & EBV): acquire from host NUCLEAR membrane ```

Question 245

What kind of vaccine is Lyme disease vaccine?

Answer 245

Recombinant bacterial outer surface protein (so similar to H. influenzae vaccine)

Question 246

What kind of vaccine is typhoid vaccine?

Answer 246

Live attenuated bacteria

Question 247

What food is assc. w/ food poisoning from preformed heat stable enterotoxin Staph aureus?

Answer 247

Custard, mayonnaise, processed/salted meats

Question 248

What process is assc. w/ heterochromatin? Euchromatin?

Answer 248

Heterochromatin: DNA methylation -> low transcriptional activity Euchromatin: histone acetylation -> high transcriptional activity

Question 249

What's the process used to deactivate one X chromosome in female?

Answer 249

Lyonization: one X chromosome is heavily methylated and forms condensed heterochromatin at the nuclear periphery -> "Barr body"

Question 250

Difference bet. carrier-mediated transport vs. channel proteins?

Answer 250

Carrier-mediated transport undergoes conformational changes as the substrate is transported

Question 251

What structure fails to develop in DiGeorge? And what's the chromosome deletion?

Answer 251

Chr 22 deletion 3rd & 4th pharyngeal/branchial POUCHES fail to develop -> no thymsus, hypocalcemic, aortic arch abnormality, mandibular deformity)

Question 252

What does septum transversum become?

Answer 252

Central tendon of diaphragm | Liver grows into this structure as an outpouching of foregut

Question 253

What does Mycobacteria microscopic growth in parallel chains correlate most strongly w/?

Answer 253

Virulence factor That pattern of growth is called "serpentine cords" and is due to cord factor. It's a mycoside (2 mycolic acid molecs bound to disaccharide trehalose) and it works by inactivating neutrophils, damaging mitochondria, and inducing release of TNF.

Question 254

What do sulfatides do for mycobacteria?

Answer 254

Inhibit fusion of lysosomes to phagosomes -> allow them to survive inracellularly

Question 255

AUG sequence positioned near the beginning of mRNA and surrounded by Kozak sequence serves what fx? Mutation 3 bases upstream from AUG in this sequence is assc. w/ what condition?

Answer 255

Initiator for translation (mRNA binding to ribosome) | Thalassemia intermedia

Question 256

Protein targeting post-translation is achieved by AA sequence at what end?

Answer 256

N-terminal -> sequence removed once it reaches final destination

Question 257

What type of hypersensitivity rxn does neutrophil play a role in?

Answer 257

Type III

Question 258

Getting blanching of vein where NE is being infused + induration & pallor of tissue surrounding IV site. What is this and how do you fix it?

Answer 258

NE extravasation caused by a1-mediated vasoconstriction | Fixed by giving phentolamine (anti-a receptors)

Question 259

How do you tell whether trisomy 21 is from nondisjunction of meiosis 1 or 2?

Answer 259

When doing restriction fragment length polymorphism on chr 21, you'll see 3 bands if nondisjunction is from meiosis I, and 2 bands w/ one being thicker if it's from meisis II (b/c inheriting sister chromatids which are the same size)

Question 260

What's the p-value for statistically significant 95% CI? 99% CI?

Answer 260

95% -> p value < 0.05 | 99% -> p value < 0.01

Question 261

5 species that can cause enteric bacteremia?

Answer 261

E. coli, Salmonella typhi, Pseudomona, Klebsiella, Proteus

Question 262

Blood & leukocytes in stool + non-lactose-fermenting, G- rods that doesn't produce gas or H2S? What's the mechanism causing disease? Transmission?

Answer 262

Shigella Mucosal invasion (Shigella is never part of normal gut flora) -> it also produces toxin, but this is NOT the main mechanism causing disease Fecal-oral transmission

Question 263

What 2 bac causing GI sx can proliferate in LN?

Answer 263

``` Yersinia enterocolitica -> pseudoappendicitis Salmonella typhi (in macrophages in Peyer's patches) ```

Question 264

Type of collagen in granulation tissue vs. mature scar?

Answer 264

Granulation tissue: type III | Mature scar: type I

Question 265

Where do you find type I collagen besides bone?

Answer 265

Tendon/ligament, dermis, cornea, blood vessels, dentin

Question 266

Where do you find type II collagen besides cartilage?

Answer 266

Nucleus pulposus, vitreous humor

Question 267

Where do you find type III collagen besides granulation tissue?

Answer 267

Reticular fibers in spleen, LN, bone marrow | Skin, lungs, intestine, blood vessels

Question 268

What 2 potential risk factors of acquiring rickettsia rickettsia?

Answer 268

Tick-born so risk goes up w/ 1. Contact w/ dogs 2. Exposure to wooded/grassy area

Question 269

What's the risk factor of acquiring Mycobacterium scrofulaceum? What's the sx?

Answer 269

Environmental water source -> so get from swimming in a pond (usually children) Lymphadinitis (usually cervical)

Question 270

What drug is used for maternal prophylaxis if mom has AIDs?

Answer 270

Zidovudine (AZT, ZDV) -> nucleoside analog that inhibits reverse transcriptase (NRTI)

Question 271

What's linkage disequilibrium and how do you know it's present?

Answer 271

A pair of alleles from 2 loci are inherited together in the same gamete more or less often than would be expected (not necessarily imply close physical proximity) Know this by calculating probability of 2 alleles appearing together => product of frequency of one allele and another (NOT 2pq like Hardy-Weignberg b/c we're comparing 2 diff loci, so just pq) If the probability shown is more or less than calculated value -> linkage disequilibrium exists

Question 272

What's pleiotropy?

Answer 272

Multiple phenotypic presentation (ie diff organs) from single gene

Question 273

2 organisms causing nongonococcal urethritis (NGU) and their differences from N. gonorrhea

Answer 273

Chlamydia: has cell wall but doesn't contain peptidoglycan, can't produce ATP on its own Ureplasma urealyticum: NO cell wall at all, can produce ATP This is why ceftrixone isn't effective against these (it targets peptidoglycan cell wall synthesis)

Question 274

How are G+ and G- different in their way of acquiring resistance to beta-lactams?

Answer 274

G+ doesn't have outer cell membrane -> beta lactams can just reach cell wall w/out having to go inside cell -> so only resistance mechanism is to alter PBP G- has outer cell membrane -> so one of the resistance mechanisms involves modification in porin proteins to prevent antibiotic entrance

Question 275

How are lysine and leucine a unique AA?

Answer 275

Essential AAs that are strictly ketogenic -> not transaminated as an initial step of metab

Question 276

Sx of zinc deficiency?

Answer 276

Acrodermatitis enteropathica (AR, periorificial and acral dermatitis + alopecia + diarrhea), growth retardation, infertility + might get nigh blindness too

Question 277

How does body get rid of copper?

Answer 277

Hepatic excretion into bile

Question 278

What are 5 diff E. coli virulence factors and diseases they create?

Answer 278

K1 CAPSULAR Ag: prevents recognition of bacterial Ag, complement fixation, and phagocytosis -> neonatal meningitis -> Ab generated against this is protective P fimbriae: allows adhesion to urothelium -> UTI Lipid A (in LPS): macrophage activation -> sepsis Verotoxin: inactivates 60S ribosome (Shigella-like) -> enterohemorrhagic E. coli (bloody diarrhea) Enterotoxin: watery diarrhea

Question 279

2 cells w/ the most important role in containing TB infection

Answer 279

Th1 (CD4+) cells and macrophages -> why some ppl get caseous granuloma w/out sx after being exposed

Question 280

What is power of a study? What variable is it related to?

Answer 280

Power: Ability to detect a difference bet. groups when a difference TRULY exists Power = 1 - Beta Beta is type II error (probability of concluding there's no difference bet. a group when the difference exists) = usually around 20%

Question 281

What's a type I error and what is the equivalence reported?

Answer 281

Type I error = probability of concluding there's a difference when a difference does NOT exist Correlates to p value

Question 282

What does osmium tetroxide stain for?

Answer 282

Stains for fat (turns up black)

Question 283

What does ricin inhibit?

Answer 283

rRNA of eukaryotic 60S subunit -> stops protein synthesis

Question 284

3 variants of Turner syndrome and what went wrong in each

Answer 284

1. 45,XO (complete monosomy) from loss of parental X during mitosis, MEIOTIC nondisjunction 2. 45,XO/46,XX OR 45,XO/46,XY (mosaicism) from MITOTIC nondisjunction 3. 46,XX partial deletion of one or more arms of X (partial monosomy) 4. structural abnormalities of X chr like X fragments or isochromosome

Question 285

What's responsible for protein primary, secondary, and tertiary structure?

Answer 285

Primary: peptide bonds Secondary: hydrogen bonds (a-helix and b-pleated sheets) Tertiary: hydrogen bonds, hydrophobic interactions, disulfide bonds (enhance ability to withstand denaturation), ionic bonds

Question 286

Formula to calculate loading dose

Answer 286

Loading dose = Vd x Css / F F = 1 in IV Loading dose remains unchanged in pts w/ hepatic/renal impairment, it's the maintenance dose that you need to adjust

Question 287

What do LTC4, LTD4, LTE4 do?

Answer 287

Vasocontriction, increases vascular permeability, bronchospasm

Question 288

4 situations where disclosure of pt info doesn't need consent

Answer 288

suspected abuse gunshot/knife wound reportable communicable disease harming self or others

Question 289

What does Vi Ag in salmonella do?

Answer 289

Prevents opsonization and phagocytosis

Question 290

What direction does DNA polymerase form new daughter strand?

Answer 290

synthesizes from 5' -> 3' (so read the parent strand from 3' -> 5')

Question 291

What proteins facilitate initial separation of dsDNA at the origin of replication for helicase?

Answer 291

DnaA protein and strand binding proteins (SSB)

Question 292

What is dentinogenesis imperfecta and what condition do you see this in?

Answer 292

Small malformed teeth | See this in osteogenesis imperfecta

Question 293

Transduction vs. transformation vs. conjugation vs. transposons

Answer 293

Transduction: bacteriophage Transformation: takes up exogenous DNA (also use this term when viral DNA gets incorporated into host chromosome) Conjugation: donor produces sex pilus Transposons: mobile genetic elements that move gene between and w/in bac chromosome, plasmids, phages

Question 294

What's the disease caused by Mycobacterium kansasii? What's the source of contamination?

Answer 294

Disease similar to MTB, acid-fast rods | Gets it from municipal drinking water system (not frequently found in nature)

Question 295

Inheritance of andregenetic alopecia if X-linked recessive is not a choice?

Answer 295

Polygenic inheritance w/ variable penetrance

Question 296

What happens to tRNA that's mischarged w/ incorrect AA?

Answer 296

Wrong AA will be incorporated into polypeptide Some AA-tRNA synthetases have proofreading activity, but if it's past that phase and AA is charged, there's no AA proofreading during protein translation itself

Question 297

What does nitroblue tetrazolium test for?

Answer 297

CGD -> neutrophils will fail to turn blue if NADPH oxidase deficiency

Question 298

What does Staph coagulase do exactly?

Answer 298

Activates prothrombin -> conversion of fibrinogen to fibrin -> fibrin coats org -> resistance to phagocytosis

Question 299

What different mechanism do viruses w/ SS, negative-sense RNA use for transcription?

Answer 299

Cap snatching: some viruses have endonuclease that cleaves 5'RNA fragments that are used to prime viral RNA for transcription by viral RNA polymerase

Question 300

What does Tzanck smear detect? What about Papanicolaou smear?

Answer 300

Tzanck smear: HSV or VZV | Pap smear: HPV

Question 301

What does hemadsorption test detect?

Answer 301

Influenza and parainfluenza viruses

Question 302

3 mycobacterial virulence factors?

Answer 302

Sulfatides Wax D Cord factor All need mycolic acids for synthesis

Question 303

What can you use for poisoning by mercury, arsenic, gold?

Answer 303

Dimercaprol - DOC for arsenic poisoning | Succimer

Question 304

What can you use for poisoning by lead and mercury?

Answer 304

EDTA - DOC for lead and mercury poisoning Dimercaprol Succimer Penicillamine

Question 305

Sx of arsenic poisoning?

Answer 305

Garlic breath odor, stomach pains, vomiting, delirium | From inhibiting lipoic acid which is a cofactor for pyruvate DH and a-ketoglutarate DH

Question 306

How do you calculate case-fatality rate?

Answer 306

Divides # of fatal cases by total # of PPL W/ DISEASE | don't consider the total mortality or other #'s assc. w/ other diseases at all

Question 307

What does NF-KB do?

Answer 307

It's TF for cytokine production

Question 308

What nucleotides are in tRNA? What does their 3' end and 5' have?

Answer 308

Acceptor stems have both 3' and 5' ends: 3' CCA tail (AA is bound to 3' terminal OH group), 5' terminal phosphate (terminal guanosine) D arm: dihydrouracil T arm (binding to ribosomes): thymidine (only RNA species containing this), pseudouridine, cytidine Anticodon arm: complementary sequence to mRNA. It's read in 3'->5'

Question 309

3 things involved in eukaryotic posttranscriptional modification? Where does this happen?

Answer 309

Poly A tail at 3' end (after AAUAAA sequence) Methylguanosine cap at 5' end Removal of introns All happen in nucleus

Question 310

4 things pts are given passive preformed Abs against after exposure?

Answer 310

"To Be Healed Rapidly" Tetanus toxin, Botulinum toxin, HBV, Rabies For HBV and rabies, combined passive and active immunizations can be given

Question 311

What cells are CD14 positive and what is this receptor directly stimulated by?

Answer 311

Macrophages | Endotoxins/LPS can directly stimulate this w/out involving Th cells

Question 312

What cells are CD56 positive?

Answer 312

NK cells | Also CD16 positive -> binds Fc of IgG to kill via Ab-dependent cell-mediated cytotoxicity

Question 313

What's a receptor for EBV on B cells?

Answer 313

CD21

Question 314

What enzymes does arsenic inhibit?

Answer 314

Arsenic inhibits lipoic acid -> so enzyme pyruvate DH (linking glycolysis and TCA) and alpha ketoglutarate DH (TCA) are affected

Question 315

What does one TCA cycle produce? How many ATPs?

Answer 315

One cycle produces 3 NADH + 1 FADH2 + 2CO2 + 1 GTP -> so (3 x 3) + (1 x 2) + 1 = 12 ATPs --> but used 2 ATP so really just generates 10 ATPs Go thru cycle twice per glucose

Question 316

Substrates/products in TCA?

Answer 316

"Citrate Is Krebs' Starting Substrate For Making Oxaloacetate" Citrate (6C), Isocitrate (6C), a-Ketoglutarate (5C), Succinyl-CoA (4C), Succinate (4C), Fumarate (4C), Malate (4C), Oxaloacetate (4C)

Question 317

3 ETC uncoupling agents?

Answer 317

Decreases proton gradient -> no ATP synthesis just heat production 2,4-dinitrophenol (illicit weight loss drug), aspirin (why get fever after overdose), thermogenin (brown fat)

Question 318

What tissues are gluconeogenesis irreversible enzymes present in?

Answer 318

Liver, renal, and intestinal tissue

Question 319

What kind of FA can serve to produce glucose and how?

Answer 319

Odd-chain FAs -> 1 propionyl-CoA can enter TCA as succinyl-CoA to serve as glucose source Even-chain FAs can't produce glucose b/c they only yield acetyl-CoA equivalents

Question 320

2 acidic AAs?

Answer 320

Acidic AAs are all about ASS | ASSpartate and glutamate (gluteus = ass muscles) -> negatively charged at body pH

Question 321

Substrates/products in urea cycle?

Answer 321

"Ordinarily Careless Crappers Are Also Frivolous About Urination" Ornithine + Carbamoyl phosphate, Citrulline + Aspartate, Argininosuccinate, Fumarate + Arginine, Urea

Question 322

What are the sx of carnitine deficiency?

Answer 322

Can't transport LCFAs into mito -> accumulation, less mito beta oxidation -> less acetyl CoA produce -> less ketone bodies produced Weakness, hypotonia, hypoketotic hypoglycemia

Question 323

What can't urine test for ketones detect?

Answer 323

B-hydroxybutyrate

Question 324

Apolipoproteins on chylomicron?

Answer 324

E (for uptake by liver cells), A-I (for LCAT activation), C-II (for lipoprotein lipase), B-48 Secreted from enterocytes w/ only ApoB-48, later get ApoC-II and ApoE from HDL

Question 325

Apolipoproteins on chylomicron remnant?

Answer 325

E (for uptake by liver cells), B-48 (lost A-I and C-II)

Question 326

Apolipoproteins on VLDL?

Answer 326

E (for uptake by liver cells), C-II (for lipoprotein lipase), B-100

Question 327

Apolipoproteins on IDL?

Answer 327

E (for uptake by liver cells), B-100 (lost C-II from VLDL)

Question 328

Apolipoproteins on LDL?

Answer 328

B-100 (lost E from IDL) | B-100 is required for receptor-mediated uptake of LDL by extrahepatic tissues

Question 329

Apolipoproteins on HDL?

Answer 329

E (for uptake by liver cells), A-I (for LCAT activation), C-II (for lipoprotein lipase)

Question 330

Enhancers/repressors location in the gene? What are their fx?

Answer 330

Location: anywhere (upstream, downstream, or w/in gene) Fx: increases/decreases rate of transcription initiation thru protein binding and interactions w/ TF bound to promoter sequence

Question 331

What happens in host cells and viral replication during abortive viral infection?

Answer 331

Little/no change in host cell | No viral replication

Question 332

Difference bet. primary and reactivated HSV-1 infection?

Answer 332

Primary: fever, vesiculoulcerative gingiovostomatitis, cervical lymphadenopathy Reactivation (from trigem ganglia): more limited -> cold sores

Question 333

How does enzyme affect energy of rxn? What does Gibbs free energy tell you?

Answer 333

Enzyme reduces energy of transition state (so reduces activation energy) -> doesn't do anything w/ Gibbs Gibbs: negative means spontaneous -> favors product, Keq will be > 1 Positive is opposite If 0 Gibbs = no net concentration change

Question 334

Why do you get anemia w/ Mycoplasma infection?

Answer 334

It shares Ag w/ RBC -> body mounts response against both orgs and own RBCs (cold agglutinins)

Question 335

Differences bet. 5'->3' exonuclease and 3'->5' exonuclease?

Answer 335

5'->3' exonuclease: only DNA polymerase I has it (assc. higher # 5 w/ lower DNA polymerase 1) 3'->5' exonuclease: proofreading activity, see in DNA polymerase I, DNA polymerase III, viral RNA polymerase (HCV lacks this in its RNA polymerase tho) -> DNA synthesis is 5'->3', so think of this as "looking back" (reverse) to make sure it's doing its job right

Question 336

What tissues can't use ketones?

Answer 336

RBCs and tissues w/out mitochondria (conversion of ketones to acetyl-CoA happens in mitochondria) Liver -> no thiophorase (succinyl-CoA-acetoacetate CoA transferase) so can't get acetyl-CoA

Question 337

What bacteria have "long branched saturated fatty acids"?

Answer 337

Mycobacteria | Described FA is mycolic acid

Question 338

Sx and timeline of scarlet fever? And what does it predispose to?

Answer 338

Incubation period of 1-5 days -> gray-white exudates in pharynx (THIS SX NOT IN KAWASAKI), strawberry tongue Then 1-2 days later -> scarlet spots/blotches (boiled lobster) of rash -> then sandpaper-like rash & circumoral pallor -> then desquamation Predispose to rheumatic fever and glomerulonephritis

Question 339

Cells that are important to limiting localized Candida infection vs. disseminated Candida infection?

Answer 339

``` Localized infections (oral thrush, esophagitis, cutaneous candidiasis, vulvovaginitis) -> T cells important! Disseminated infections -> neutrophils important! (role in limiting hematogenous spread) ```

Question 340

AA composition of collagen molecule?

Answer 340

Most abundant AA: glycine -> needs at every third AA of alpha chain in order to fold into triple helix Other minor components are proline (creates bend in polypeptide chains important to forming alpha helix) and lysine (important to cross-linking to other collagen molecs)

Question 341

What is psammoma body composed of? What are 4 things you see psammoma bodies in?

Answer 341

Composed of core dense calcification w/ surrounding collagen-fiber bundles See in PSaMM: papillary thyroid carcinoma, serous papillary ovarian adenocarcinoma, meningioma, malignant mesothelioma

Question 342

How do you calculate positive and negative likelihood ratio and what do they tell you?

Answer 342

LR+ = sensitivity / (1-specificity) -> tells you likelihood of having the disease given positive result LR- = (1-sensitivity) / specificity -> tells you likelihood of having the disease given negative result Unlike PPV & NPV, not assc. w/ prevalence!

Question 343

Infection by what orgs is assc. w/ undercooked shellfish?

Answer 343

Vibrio cholerase Norwalk virus Hep A

Question 344

What kind of substance reduces Vmax but doesn't change Km?

Answer 344

Decreases just efficacy -> so either a noncompetitive antagonist or an IRREVERSIBLE competitive antagonist

Question 345

What is usually the primary focus of cryptococcus? What is the most common manifestation?

Answer 345

Primary focus is usually lung. However it's usually asymptomatic there. The most common manifestation is meningitis b/c CSF lacks components of alternative pathway -> so impaired phagocytosis of cryptococcus

Question 346

What are transamination rxns and what vitamin do most transamination rxns require?

Answer 346

a-ketoacid + AA forms AA + a-ketoacid ie oxaloacetate (a-ketoacid) + glutamate (AA) -> aspartate (AA) + a-ketoglutarate (a-ketoacid) Requires B6

Question 347

What does carnitine do? What does it need for synthesis?

Answer 347

AA that transport FAs into mito for beta-oxidation | Synthesized from lysine + methionine + vit C

Question 348

What's the mechanism of toxins produced by C. difficile?

Answer 348

Both A and B inactivate Rho-regulatory proteins -> impaired signal transduction and actin cytoskeletal structure maintenance -> disruption of intercellular tight jx

Question 349

2 examples of drugs assc. w/ mitochondrial toxicity?

Answer 349

Cyanide and NRTIs

Question 350

What kind of vaccine is the active rabies vaccine?

Answer 350

Killed vaccine (the entire virus particles killed by beta-propiolactone)

Question 351

How do you calculate SE from SD? What does 95% mean for SE?

Answer 351

SE = SD / square root of n | So 95% CI would still be +/- 2 SE just like it does w/ SD

Question 352

Policies on using interpreters in medical settings?

Answer 352

Non-emergent settings (depressed pts in ER count too): wait for TRAINED interpreters Emergent settings: can use friends/family, writing, hospital staff, anything that can help quickly

Question 353

What molecule do you use as a marker for mast cell activation/anaphylaxis?

Answer 353

Tryptase

Question 354

4 stages of sx of iron poisoning?

Answer 354

Stage 1: nausea, diarrhea, abd pain, hemorrhage (hematemesis and melena!), hypovolemia, shock Stage 2: appears better Stage 3: metabolic acidosis, hepatic dysfx, hypoglycemia Stage 4: scarring of recovering GI tract

Question 355

What yeast appears red on mucicarmine stain?

Answer 355

Cryptococcus

Question 356

What enzyme allows you to synthesize ribose from fructose-6-P when you don't have NADPH from oxidative side of HMP shunt?

Answer 356

Transketolase and transaldolase from the nonoxidative portion of HMP shunt

Question 357

What's one purpose of oxidative half of HMP shunt? Nonoxidative half?

Answer 357

Oxidative half = to generate NADPH for use in glutathione reduction rxn and enzymes involved in FA, cholesterol and steroid synthesis Nonoxidative half = to make ribose 5-P from intermediates of glycolysis

Question 358

What's a rare disease assumption?

Answer 358

Odds ratio approximates relative risk when disease prevalence is low

Question 359

A graph of drug glucuronide conc (y) vs. drug dose (x) shows a rise then plateau. What does each segment represent?

Answer 359

The first linear segment w/ positive slope = first order kinetics = increase in PROPORTION (percentage) of drug is metab w/ increase in drug dose The reflection point = where first order is changed to zero order The plateau segment (enzyme saturation) = zero order kinetics = constant AMOUNT of drug is metab regardless of drug dose

Question 360

Steps and locations of collagen synthesis?

Answer 360

RER: special sequence at N-terminus facilitates ribosomal binding to RER and guides growing pre-pro-alpha chains into RER -> then N-terminus signal peptide is cleaved -> proline and lysine hydroxylation, vit C required -> glycosylation w/ galactose and glucose -> central region flanked by globular N- and C-terminal extensions (propeptides) -> disulfide bond formation (triple helix procollagen molecule formed) Golgi: send procollagen triple helix out of cell Extracellular: Propeptides at N and C-termini are cleaved by procollagen peptidase to form insoluble tropocollagen molecs -> self-assembly into collagen fibrils that are then X-linked by lysyl oxidase

Question 361

Where do you find Moraxella catarrhalis? What does it cause?

Answer 361

Normal flora of URT Causes otitis media and sinusitis in healthy ppl Might cause exacerbation of COPD

Question 362

How do you prevent neonatal GBS sepsis?

Answer 362

Give INTRAPARTUM penicillin prophylaxis to mother

Question 363

What type of hypersensitivity is acute serum sickness and what's the example of how you get this?

Answer 363

Type III HSR: so immune complex, neutrophils infiltration, fibrinoid necrosis, hypocomplementemia Example: 7-14 days after starting infilximab for Crohn, present w/ fever, pruritic RASH & ATHRALGIAS

Question 364

What does coefficient of variation quantify? How do you calculate it?

Answer 364

Quantifies reliability of a test | Calculated by SD divided by mean

Question 365

Do you get more or less expression w/ histone DEacetylation?

Answer 365

Deacetylation -> less expression b/c chromatin is closed

Question 366

Rules for dating FORMER pts?

Answer 366

Can do it if you're not a psychiatrist

Question 367

When do you give H. influenzae b vaccine? What kind of immunity does it stimulate?

Answer 367

Beginning at 2 mo Immunity during the first couple of months prior is acquired by transient maternal transplacental IgG Vaccine stimulates HUMORAL immunity

Question 368

What end does telomerase add to?

Answer 368

3' | Should make sense since DNA synthesis occurs from 5' -> 3'

Question 369

What do you use to stain diphtheria's metachromatic granules?

Answer 369

Aniline dyes (like methylene blue)

Question 370

What neurotransmitters are inhibited by tetanus toxin?

Answer 370

GABA and glycine (both inhibitory)

Question 371

A single mutation can cause orotic aciduria affects what 2 enzymes?

Answer 371

Orotate phosphoribosyl transerase and OMP decarboxylase -> they're separate active domain on a single polypeptide so a single mutation will cause dysfx of both This type of orotic aciduria comes w/ megaloblastic anemia (unlike ornithine transcarbamylase deficiency) and need uridine supplementation.

Question 372

2 orgs commonly isolated from intraabdominal infections?

Answer 372

B fragilis and E coli

Question 373

Org isolated from infection from perforation of proximal bowel like peptic ulcer?

Answer 373

Candida

Question 374

What's the org that cause diarrhea that can be passed on from domestic animals?

Answer 374

Campylobacter | Can also be passed on from contaminated food (like undercooked poultry and unpasteurized milk)

Question 375

What pts are prone to developing hypercalcemia and hypercalciuria?

Answer 375

pts w/ granulomatous disorders: sarcoidosis, TB, Hodgkin's, non-Hodgkin's

Question 376

What AA makes NO?

Answer 376

Arginine

Question 377

What AAs make urea?

Answer 377

Arginine + aspartate

Question 378

What AA makes heme?

Answer 378

Glycine and succinyl CoA

Question 379

What AAs make creatine?

Answer 379

Glycine + arginine + SAM

Question 380

What AAs make pyrimidine?

Answer 380

Glutamate + aspartate

Question 381

What AAs make purines?

Answer 381

Glutamate + aspartate + glycine

Question 382

What AA makes melatonin? Melanin?

Answer 382

Tryptophan -> serotonin -> melatonin (tryptophan also makes niacin) Tyrosine -> thyroxine -> melanin (tyrosine also makes dopamine)

Question 383

What does PAF do besides the obvious stuff?

Answer 383

Platelet-activating dactor | Causes vasoconstriction, bronchoconstriction, enhannces leukocytes adhesion, chemotaxis, phagocytosis, degranulation

Question 384

What molecs increase ESR?

Answer 384

IL-1, IL-6, TNF-a stimulate hepatic secretion of acute-phase proteins like fibrinogen -> fibrinogen makes RBCs form stacks and increases ESR

Question 385

What 4 drugs can cause increased toxicity in slow acetylators?

Answer 385

Isoniazid, dapsone, hydralazine, procainamide

Question 386

What does Klebsiella look like on gram stain?

Answer 386

Obv gram negative | Thick capsule seen as clear zone + mucoid growth

Question 387

What does Klebsiella pneumonia classically affect?

Answer 387

Alcoholics: colonizes oropharynx followed by microaspiration, upper lobes commonly affected

Question 388

What's a Samter's triad?

Answer 388

Asthma + aspirin hypersensitivity + nasal polyposis

Question 389

What's salicylism?

Answer 389

From high-dose aspirin Vertigo + tinnitus + hearing loss Aspirin stimulates resp drive -> resp alkalosis -> salicylate accumulation -> metabolic acidosis

Question 390

Enzymes in peroxisomes? What metabolic fx do peroxisomes do?

Answer 390

Oxidative enzymes like catalase, D-amino acid oxidase, and uric acid oxidase Metabolic fx are beta oxidation of VLCFA and alpha oxidation of branched chain FAs like phytanic acid -> get Zellweger syndrome (can't properly form myelin in CNS) or Refsum disease (alpha defect -> phytanic acid accumulates -> avoid chlorophyll in diet) Energy from beta oxidation is used to generate H2O2

Question 391

Antibiotics that work on 50S ribosomes? 30S ribosomes?

Answer 391

50S: chloramphenicol, clindamycin, linezolid, macrolides 30S: tetracycline, doxycycline, aminoglycosides

Question 392

What do tat gene and nef gene do for HIV?

Answer 392

tat gene: viral replication | nef gene: decreases MHC I expression on surface of infected cells

Question 393

What gives collagen diversity in different tissues?

Answer 393

Variation in AA sequences in alpha chains

Question 394

What do you need to supplement in media to grow mycoplasma?

Answer 394

Cholesterol

Question 395

What AAs are both glucogenic and ketogenic?

Answer 395

Phenylalanine, isoleucine, tryptophan

Question 396

When do you typically seen nafcillin being used?

Answer 396

Skin and soft tissue infections (folliculitis, abscesses) typically caused by S. aureus (don't assc. folliculitis only w/ pseudomonas b/c S. aureus can cause this too!) NOT food poisoning caused by the same org -> supportive tx only for that b/c it's a toxin-mediated illness and antibiotics won't do anything

Question 397

Tenosynovitis + pharyngitis. What org should you be thinking about?

Answer 397

N. gonorrhoeae

Question 398

How can vit C deficiency present in children?

Answer 398

More severe -> might see subperiosteal and joint hematomas

Question 399

What 2 rxns is thiamine important for?

Answer 399

Pyruvate -> acetyl CoA | Alpha-ketoglutarate -> succinyl CoA

Question 400

2 components of telomerase?

Answer 400

TERT: reverse transcriptase TERC: RNA template

Question 401

How does Babesia divergens present? What region is high risk?

Answer 401

Malaria-like illness w/ predilection for asplenic pts | Endemic on NE coast of US

Question 402

How does Isospora belli present?

Answer 402

Chronic, watery, profuse diarrhea in immunocompromised (AIDs especially)

Question 403

What does fluid look like on CT?

Answer 403

Isodense w/ muscle -> so look for asymmetry bet. 2 sides b/c hematomas might blend in

Question 404

3 biases named after ppl?

Answer 404

Hawthorne effect: subject changes behavior b/c they're aware they're being studied Berkson's bias: selection bias (choosing inpatient as control group) Pygmalion effect: researcher's belief in efficacy can potentially affect outcome (self-fulfilling prophecy)

Question 405

What are HIV's pol gene mutations responsible for? Env gene mutations?

Answer 405

Pol gene mutations: acquired resistance to NNRTIs & NRTIs & protease inhibitors Env gene mutationTs: escape from host neutralizing Ab

Question 406

Example of drug that's excreted unchanged?

Answer 406

Diuretic chorothiazide

Question 407

Drugs that undergo liver sulfate conjugation? What does that do?

Answer 407

Liver sulfate conjugation: phase II metab that transforms drug into more polar drug for excretion Drugs: phenol and chloramphenicol

Question 408

Drugs that undergo liver hydroxylation? What does that do?

Answer 408

Hydroxyl group is added to produce less lipid-soluble compounds Drugs: pentobarbital and phenobarbital

Question 409

Drugs that undergo liver hydrolysis? Plasma hydrolysis?

Answer 409

``` Liver hydrolysis (phase I metab): procaine, lidocaine, aspirin Plasma hydrolysis: succinylcholine, tetracaine, remifentanil ```

Question 410

Drugs that under go liver acetylation? What condition are they linked to?

Answer 410

Hydralazine and procainamide | Linked to drug-induced lupus

Question 411

What vitamin deficiency is assc. w/ differentiation of specialized epithelia? And what are the results?

Answer 411

Vit A Deficiency = SQUAMOUS METAPLASIA from mucus-secreting columnar to keratinizing epithelium (see in ocular conjuctiva, respiratory, urinary, pancreatic, other exocrine ducts)

Question 412

3 enzymes that start w/ the word "pyruvate" and the differences bet. them?

Answer 412

Pyruvate kinase: makes pyruvate from PEP Pyruvate DH: oxidative phosphorylation (going forward from glycolysis to TCA cycle) Pyruvate carboxylase: gluconeogenesis (converted to oxaloacetate for the purpose of going back up)

Question 413

Defects involving 2 enzymes that cause homocystinuria and the similarities/differences bet. them?

Answer 413

Both will cause homocystinuria & thrombosis/atherosclerosis risk + Marfanoid habitus + lens subluxation (but downward & inward instead of upward and temporally like Marfan) Differences: - More common: anything involving defects in cystathionine synthase (like enzyme deficiency or reduced affinity to its cofactor B6) -> supplement B6, B12, folate, cysteine, and restrict methionine - Less common: homocysteine methyltransferase (methionine synthase) deficiency -> supplement methionine!

Question 414

4 virulence factors of strep pneumo?

Answer 414

1. polysac capsule (quellung rxn -> halo around blue-stained bacterial cell when anti-capsular Ab and methylene blue dye are added to it) -> prevents phago 2. IgA protease 3. Adhesins 4. Pneumolysin -> causes pores in cell membrane -> cell lysis

Question 415

What does M protein in strep pyogenes do?

Answer 415

Anti-phago, also binds fibrinogen (inflammatory mediator release and vascular leakage) This is what serogroups are based on! -> M protein stimulates type-specific immunity

Question 416

What 2 drugs cause acquired nyctalopia (night blindness)

Answer 416

Phenothiazines or chloroquine

Question 417

What vitamin deficiency are you at risk of if you're on strict vegetarian diet?

Answer 417

Cobalamin

Question 418

What infection is assc. w/ transfusion?

Answer 418

CMV (lives in leukocyte-laden blood products)

Question 419

What are secreted toxin and toxin bound to outer peptidoglycan of S. aureus?

Answer 419

Secreted toxin: hemolysin (destroy RBCs, neutrophils, macrophages, platelets) Toxin bound to peptidoglycan: protein A (binds IgG and prevents complement activation)

Question 420

What does Giardia look like? What's the major immune mechanism against it? And what do you see under the microscope?

Answer 420

Trophozoite is pear-shaped w/ multiple flagella and 2 nuclei; cysts are oval w/ up to 4 nuclei Immune mechanism: CD4+ and secretory IgA (so anyone w/ IgA deficiency, agammaglobulinemia, and CVID are susceptible to chronic infection) Histo: villus atrophy and crypt hyperplasia

Question 421

How do you distinguish MAC from extrapulm TB? How do you treat it?

Answer 421

MAC: grows at higher temp (41 C) and widespread reticuloendothelial involvement -> so see marked anemia, hepatosplenomeg, elevated alk phos, elevated lactate DH Tx: clarithromycin/azithromycin + rifabutin/ethambutol Give prophylactic azithromycin if CD4+ < 50

Question 422

2 characters that tell you for sure that tumors are anaplastic

Answer 422

Mitotic figures Giant, multinucleated tumor cells (bronchial epithelial cells producing keratin pearls isn't considered anaplastic, because it only requires metaplasia to be able to do that)

Question 423

What is referral bias?

Answer 423

Populations differ due to admission or referral practices -> a study involving cancer risk factors at hospital specializing in cancer research might enroll cases referred from all over the country, while hospitalized control subjects w/out cancer may only come from local area

Question 424

What is detection bias?

Answer 424

Risk factor itself may lead to extensive dx investigation & increases the probability that a disease is identified (ie smokers undergo increased imaging surveillance b/c of their smoking status)

Question 425

What is allocation bias?

Answer 425

Bias from the way tx and control groups are assembled -> assigned in a non-random fashion Example: study comparing oral NSAIDs and intraarticular corticosteroid injections might have obese pts preferentially assigned to corticosteroid group

Question 426

Why do you get multiple organ involvement w/ MEN2 syndromes?

Answer 426

B/c they're all from neural crest cells! So this should help you remember that parathyroid cells, parafollicular cells of thyroid (medullary), and adrenal medulla are from neural crest cells

Question 427

Why don't you get more sx w/ fructokinase deficiency?

Answer 427

B/c hexokinase can still convert fructose to fructose 6-P -> this can go on to produce glycogen, glucose, or participate in pentose phosphate pathway

Question 428

What 3 groups of bac produce hyaluronidase and what is it used for?

Answer 428

Produced by staph, group A strep, C. difficile | Used to digest extracel ground substance -> enhance ability to spread

Question 429

Immunohistochemical stains for muscles?

Answer 429

Actin Caldesmon Desmin

Question 430

How do you dx infection w/ C. tetani?

Answer 430

H&P, incl vaccine hx (booster recommended every 10 years) Won't be able to do blood culture b/c only found locally at the wound No serum toxin assay available

Question 431

What Ig is found circulating as dimers? And where do you find it?

Answer 431

``` SECRETORY IgA (in serum will be a monomer) - the secretory piece of the molec is actually synthesized by epithelial cells while other parts are from plasma cells -> this part is to prevent degradation in secretions Found in mucus, tears, saliva, colostrum ```

Question 432

What's the strain of E. coli that doesn't ferment sorbitol or produce glucuronidase like other strains?

Answer 432

O157:H7 E. coli

Question 433

6 bac toxins that activates adenylate cyclase?

Answer 433

``` B. pertussis (pertussis toxin) B. anthracis (edema factor) ETEC (heat labile toxin) C. jejuni (enterotoxin) B. cereus (heat labile enterotoxin) V. cholerae (choleragen toxin) ```

Question 434

2 bac toxins that activate guanylate cyclase?

Answer 434

ETEC (heat stable toxin) | Y. enterocolitica (enterotoxin)

Question 435

3 ways to transport mitochondrial oxaloacetate (OAA) to cytosol

Answer 435

1. use mitochondrial PEPCK to convert it to PEP 2. transaminate it to aspartate 3. reduce it to malate

Question 436

What do you do if pts ask you to perform a prodecure that's against your personal belief (like abortion)?

Answer 436

You don't have to do it, but have to provide referral who will perform the requested procedure

Question 437

3 drugs that inhibit dihydrofolate reductase (prevents reduction of folic acid to THF)?

Answer 437

Trimethoprim: in bacteria Methotrexate: in human Pyrimethamine: in parasites

Question 438

Most common source of E coli bacteremia?

Answer 438

UTIs | Gut is the site of origin, but not typically the site of infection

Question 439

2 disorders where you see urine turns dark upon exposure to air and how to distinguish them?

Answer 439

acute intermittent porphyria and alkaptonuria AIP will have acute sx of abd pain and neuropsychiatric things, whereas alkaptonuria is pretty mild and will just have pigment depositions to diff parts in the body (ochronosis)

Question 440

Does beta blockers have effect on circulating levels of catecholamines?

Answer 440

NO | clonidine does because it stimulates a2 -> decreases catecholamines

Question 441

Pancoast tumor causing face and right arm swelling & engorgement of subQ veins but only on one side. What vein does it compress?

Answer 441

Brachiocephalic Sx identical to SVC syndrome but on just one side of the body Remember that external jugular joins subclavian -> then subclavian and internal jugular join to become brachiocephalic (which on the right side also drains right lymphatic duct)

Question 442

What 5 orgs are ppl w/ CGD susceptible for?

Answer 442

Think CATALASE-positive (not oxidase, stop confusing them) -> so the usual ones in sketchy micro like staph aureus, nocardia, aspergillus But also Burkholderia cepacia, Serratia marcescens

Question 443

Ceft lip vs. cleft palate?

Answer 443

Cleft lip: maxillary prominences fail to fuse w/ intermaxillary segment (medial nasal prominence) Cleft palate: palatine shelves of maxillary prominence fail to fuse w/ one another or w/ primary palate (which is formed from intermaxillary segment)

Question 444

What 4 rxn should you be thinking about that need biotin (B7)? How do you get deficiency?

Answer 444

Biotin acts as CO2 carrier so used in enzyme that adds C to substrate -> the "carboxylases" Acetyl-CoA carboxylase Pyruvate carboxylase Propionyl carboxylase Beta-methylcrotonyl CoA carboxylase Deficiency from excessive raw egg white consumption (avidin binds B7)

Question 445

What factor most increases the risk of dying by suicide?

Answer 445

Access to firearms

Question 446

Conditions assc. w/ impaired DNA repair?

Answer 446

``` Xeroderma pigmentosum (nucleotide base excision repair) Fanconi anemia (AR hypersensitivity to X-linking agents) Bloom syndrome (AR hypersensitivity to UV damage and chemo) ```

Question 447

What do you use in Wilson's disease?

Answer 447

Penicillamine!

Question 448

What process is responsible for double positive T cells?

Answer 448

TCR beta gene rearrangement (pro-T cells arrive at thymus as double-negative and undergo this process in thymic subcapsular zone)

Question 449

Diff in Ag processing and structures of MHC I and MHC II?

Answer 449

MHC I: proteasome then Ag sent to RER by TAP (transporter associated w/ Ag processing) -> MHC I sent out to surface w/ Ag already bound; structure is heavy chain and B2 microglobulin MHC II: sent out of RER w/ invariant chain -> invariant chain cleaved off after fusing w/ acidified phagolysosomes containing foreign Ag; structure is alpha and beta polypeptide chains

Question 450

What's the co-stimulatory signal for T cell activation?

Answer 450

CD28 (on T cells) | B7 (on APC)

Question 451

Example of how you get DNA base alterations? Enzyme sequence of BASE excision repair (NOT nucleotide excision repair)?

Answer 451

Nitrates consumption leads to deamination of cytosine (forming uracil), adenine (forming xanthine), and guanine (forming hypoxanthine) Enzyme sequence: glycosylases (cleave altered base) -> endonuclease (cleaves 5' end of apurinic-apyrimidinic site) -> lyase (removes sugar phosphate group) -> DNA polymerase -> ligase

Question 452

Where do you find teichoic acid?

Answer 452

Linked to peptidoglycan cell wall of G+ (none in G-)

Question 453

What receptors mediate epinephrine actions on systolic BP and diastolic BP?

Answer 453

Systolic: increased by b1 & a1 Diastolic: decreased by b2 predominance at low dose, increased by a1 predominance at high dose

Question 454

Pathologists who knew diabetes status of pts were 3 times more likely to interpret sample microscopy as diabetic nephropathy. What kind of bias is this?

Answer 454

Observer bias

Question 455

What's a phenotypic mixing and how is it different from reassortment?

Answer 455

Both involve co-infection by 2 viruses in one host cells Phenotypic mixing doesn't actually involve a change in genome -> you get mixing of viral surface proteins which might allow one virus to be infectious to the type of cell it couldn't infect before, but the next generation will actually be the original virus and can't infect those cells Reassortment involves change in genome so the next generation will be infectious to a new type of cells as well

Question 456

What's interference?

Answer 456

One virus inhibits the replication/release of a second virus that's infecting the same cell

Question 457

How do you calculate attributable risk percent in the exposed? What is another name for it?

Answer 457

ARP = 100 x (RR-1) / RR ARP = 100 x (risk in the exposed - risk in unexposed) / risk in exposed Another name is relative risk reduction (RRR) if not doing percent and if talking about tx instead (the bottom # would be the control)

Question 458

What does PAS stain for exactly?

Answer 458

Oxidizes C-C bonds forming aldehyades -> produce magenta color upon reacting w/ fuscin-sulfurous acid So this is good at highlighting polysaccharides (fungal cell wall), mucosubstances, BM Use distastase in conjunction if wanna wash glycogen away -> things like Wipple will be magenta w/ PAS and is disastase-resistance

Question 459

What are 2 stains used for neutral lipids?

Answer 459

``` Nile red Sudan bblack (useful for frozen section) ```

Question 460

How do you distinguish bet. NADPH oxidase deficiency and myeloperoxidase deficiency in CGD?

Answer 460

Use nitroblue tetrazolium and dihydrorhodamine flow cytometry testing -> in NADPH deficiency neutrophils won't turn blue (NBT) or fluorescent green (DHR), in myeloperoxidase both will be normal

Question 461

Mechanism and cell death curve of exposure to radiation?

Answer 461

Kills cells by 2 mechanisms -> DNA double strand break and free radicals Death curve: initially flat line followed by steep increase in cell death

Question 462

The level of what molecule distinguishes bet. folic acid and B12 deficiency?

Answer 462

Methylmalonyl CoA -> only elevated in B12 (why get neuro sx) | Both will have elevated homocysteine

Question 463

2-yo got treated for presumptive rotavirus-induced gastroenteritis. Now came back a few days after discharge w/ abdominal distention and diarrhea after each feeding. What enzyme defect should you be thinking about?

Answer 463

Secondary lactase deficiency (gastroenteritis damaged intestinal epithelium)

Question 464

Tx of acute diphtheriae infection in order of importance?

Answer 464

1. antitoxin (passive immunity) -> most important on prognosis but ineffective against toxin that has already gained access to cardiac or neural cells 2. penicillin or erythromycin 3. DPT vaccine (active immunity)

Question 465

What are intracellular orgs protected against?

Answer 465

Ab and complement! -> so think cell-mediated immunity anytime you have intracellular bac -> this cell mediated immunity might lead to macrophage activation and killing

Question 466

What 2 intracel orgs block fusion of phagosomes w/ lysosomes?

Answer 466

TB and salmonella

Question 467

What intracel org inhibits phagolysosome acidification?

Answer 467

TB

Question 468

What 2 intracel orgs escape from phagosome into cytosol?

Answer 468

Listeria and Shigella

Question 469

What does listeriolysin O do?

Answer 469

Pore-forming toxin (secreted by Listeria) that is selectively activated w/in acidified phagosomes

Question 470

Why do you use glucagon for beta blocker overdose?

Answer 470

It activates G protein on cardiac myocytes -> increased cAMP -> Ca2+ release from intracellular stores -> increased SA firing

Question 471

In organophosphate poisoning, what can't you fix w/ atropine that you can w/ pralidoxime (if administered fast enough)?

Answer 471

Muscle paralysis -> b/c this is nicotinic effect and atropine only fixes muscarinic effects Pralidoxime works on restoring AChE so works on both nicotinic and muscarinic effects

Question 472

What's the cutoff for "fever" and what's the mechanism behind it?

Answer 472

> 38.3 C Cytokines (IL-1, 6, TNF) enters brain and stimulates phospholipase A2 release of arachidonic acid -> PGE2 released and leads to increase in thermoregulatory set point in ant. hypothalamus (why NSAIDs and acetaminophen are antipyretics)

Question 473

What's the cutoff for "hyperpyrexia" and how do you manage this?

Answer 473

> 40 C Cooling measures first (cooling blanket) to prevent brain damage (purkinje cells of cerebellum esp sensitive to heat damage!) Then antipyretics (NSAIDs; or oral and rectal acetaminophen equally effective)

Question 474

Where does staph aureus colonizes in carriers?

Answer 474

Ant. nares

Question 475

Langhans cells vs. Langerhans cells?

Answer 475

Langhans cells: mutinucleated giant cell w/ horseshoe-shaped arrangement (nuclei derived from monocytic cell line that plays a role in granulomatous inflammation) Langerhans cells: APC of skin

Question 476

What 2 kinds of study do you calculate median survival for?

Answer 476

Cohort studies or clinical trials

Question 477

What kind of study do you calculate prevalence odd ratio for?

Answer 477

Cross-sectional studies

Question 478

What does secretory IgA do exactly?

Answer 478

Binds and inhibits action of pili & surface Ag that mediate mucosal adherence and penetration Does NOT fix complement or opsonize

Question 479

4 examples of orgs that don't need high infection dose to cause disease?

Answer 479

Shigella (b/c of its unique binding site on M cells -> usually unoccupied by normal gut flora so easier attachment and invasion) C. jejuni Entamoeba Giardia

Question 480

The activity of what enzyme INCREASES in Lesch-Nyhan?

Answer 480

It's from decreased HGPRT activity (failure of purine salvage) -> so get PRPP accumulation (substrate) -> phosphoribosyl pyrophosphate amidotransferase uses this to form phosphoribosylamine in the first commited step of de novo purine synthesis (so activity of this enzyme is increased)

Question 481

What's special about the final step in de novo purie synthesis?

Answer 481

IMP is converted to either AMP or GMP GMP formation requires ATP and AMP formation requires GTP -> cross-regulation that decreases synthesis of one nucleotide when the other is deficient

Question 482

2 ways to get toxo?

Answer 482

Oocysts: eat/drink water contaminated w/ cat feces Pseudocysts: eat undercooked meat

Question 483

What kind of antibiotics should you think about when usage makes bac more prone to disintegrate when placed in hypotonic solution?

Answer 483

Think about anything that works on peptidoglycan -> this is what makes bac resistant to osmotic stress

Question 484

What orgs should you think about in acute orchitis in young adults? Older pts?

Answer 484

Young adults: C. trachomatis, N. gonorrhoeae | Older pts: E. coli

Question 485

When do you give MMR?

Answer 485

12-15 mo

Question 486

What does ether/organic solvent test distinguish between?

Answer 486

Enveloped and nonenveloped viruses -> enveloped viruses will be inactivated by ether and organic solvents

Question 487

What kinds of cells do medullary cords in LN contain?

Answer 487

B cells, plasma cells, macrophages

Question 488

What kinds of cells do medullary sinuses in LN contain?

Answer 488

Reticular cells, macrophages

Question 489

Where are subcapsular sinuses in LN?

Answer 489

Bet. capsule and cortex -> connects w/ afferent lymphatic vessels and cortical sinuses (which connect to single efferent lymphatic channel at hilum)

Question 490

Granuloma formation 2 wks post laceration. Normal or what's wrong?

Answer 490

Not normal -> by now should get the start of maturation phase (fibrosis) Granuloma formation prob due to foreign bodies (like retained suture) -> shows up clinically as tender erythematous brown/purple papule/nodule/plaque

Question 491

What is orotic acid a precursor of?

Answer 491

Pyrimidine

Question 492

What is a frequent site of nosebleed called? And what arteries form it?

Answer 492

Kiesselbach's plexus - ant. part of nasal septum | Formed from sphenopalatine artery (branch of third part of maxillary) + ophthalmic artery + facial artery

Question 493

5 AAs that are nonpolar. Where would you see these?

Answer 493

Valine, alanine, isoleucine, methionine, phenylalanine | Prob see these on transmembrane region of receptors (bc they're hydrophobic)

Question 494

What should you give animals deprived of folic acid to reduce erythroid precursor apoptosis?

Answer 494

Thymidine This is b/c the rxn generating dTMP de novo needs folic acid; so giving thymidine will help shunt dTMP production from de novo pathway to salvage pathway (thymidine kinase)

Question 495

What AA does biosynthesis of dUMP (pyrimidine precursor) need?

Answer 495

Glutamine

Question 496

2 types of rxn that B6 is important for?

Answer 496

Transamination | Decarboxylation

Question 497

What do you need in PCR rxn? What are the steps?

Answer 497

DNA template, 2 primers (need to know the FLANKING sequence not the actual target sequence), heat-stable DNA polymerase, deoxynucleotide triphosphates Steps: heating (DNA strand denaturation), cooling (primer annealing), rewarming (primer extension and DNA syntehsis)

Question 498

What do you need in RT PCR rxn?

Answer 498

cDNA (produced by reverse transcriptase enzyme using mRNA as template) Don't need to know sequence of cDNA tho

Question 499

After normal control period, blood flow to the extremity of anesthetized animal is completely occluded for 1 minute. When the occlusion is released, blood flow increases abruptly and exceeds the control value for several minutes (reactive hyperemia). After an appropriate recovery period, the procedure is repeated and the extremity is actively exercised during the occlusion period. What would describe the reactive hyperemia after the second occlusion compared with that after the first occlusion?

Answer 499

Increased Exercise will increase production of waste products (lactate, CO2, etc) -> more dilatation of local circulation -> more reactive hyperemia after clamp is removed

Question 500

How do you sterilize bedpan from C. diff?

Answer 500

Expose to saturated steam (120 C) for 15 min