practice test 2 Flashcards
what are 2 inherited causes of premature coronary artery disease
familial hypercholesterolemia (LDL receptor or ApoB100 deficiency) or familial dysbetalipoproteinemia (defective ApoE)
What does a low-pitched, rumbling, mid-diastolic murmur heard best over the apex when the patient is lying in the left lateral decubitus position indicate
mitral stenosis
Peutz-Jeghers syndrome is an autosomal dominant disease characterized by _____ and _______
mucocutaneous pigmented macules
gastrointestinal hamartomatous polyps (prone to bleeding and increased risk for malignant transformation)
what is a hamartoma
overgrowth of tissue in its native location
What mass will histologically show nuclear indentations and round clear cytoplasmic vacuoles scalloping of the nuclear membrane
liposarcoma
Differentiate pemphigus vulgaris and Bullous pemphigoid
pemphigus vulgaris:
IgG agaisnt demoglein-1 or desmoglein-3 (part of desmosomes between karatinocytes)
oral involvement
extension of lesion with direct pressure
flaccid blisters
IgG and C3 deposits on fluorescence = net-like
bullous pemphigoid: IgG against hemidesmosomes (epidermal basement membrane) tense blisters eosinophils linear pattern on fluorescence
Patients with alcohol related _____ degeneration experience ataxia that may present as broad based gait, truncal instability, tremor, dysarthria, and diplopia
cerebellar
cerebellar vermis; due to loss of Purkinje cells
How does lithium cause diabetes insipidus
nephrogenic: impairs aquaporin 2 water channels and reduces responsiveness to endogenous and exogenous vasopressin
Brisk rectal bleeding in a 2 yr old previously healthy child with no other symptoms including no abdominal tenderness or distention with normoactive bowel sounds is most likely due to what
mekel divertriculum with gastric mucosa
Prokaryotic _____ is responsible for the removal of RNA primers and the synthesis of new DNA in their place
DNA polymerase I
what is 1-specificity
false positive rate
Lynch syndrome has increased risk of what neoplasms and is associated with what gene mutation
colorectal
endometrial
ovarian
mismatch repair genes (MSH2, MLH1, MSH6, PMS2)
CA-125 is a common tumor marker for what
ovarian cancer
Ticrolimus MOA
calcineurin inhibitor (immunosuppressive)
cyclosporine MOA
calcineurin inhibitor (immunosuppressive)
How are calcineurin inhibitors (tacrolimus, cyclosporine) nephrotoxic
arteriolar vasoconstriction (afferent and efferent) --> increased blood urea nitrogen and creatinine long term use --> obliterative vasculopathy, tubular vacuolization , and glomerular scarring
A 2 yr old with black stains on her cloth diapers when a wet diaper is not immediately changed is what diagnosis? due to what deficiency?
alkaptonuria
defect in homogentisic acid dioxygenase –> impaired tyrosine metabolism
elevated homogentisic acid levels in urine
tx: restrick phenylalanine and tyrosine
other symptoms: ochronotic osteoarthropathy
What are the relative extracellular levels of the following electrolytes during ischemia: Na K Ca HCO3
reduced Na/K ATPase –> extracellular K increased and Na decreased
Extracellular Ca and bicarb: decreased
(intracellular Ca accumulation is hallmark of ischemic injury)
homocystinuria lens subluxation vs Marfan syndrome
homocystinuria: down and in
Marfan: up and out
why is heparin permitted during pregnancy but warfarin is not
warfarin has a low molecular weight, allowing it to cross the placenta to produce teratogenic effects
what is the main bacterial factor responsible for N. gonnorrhea to initiate infection
pili
_____ describes the mixing of genomic segments in segmented viruses that infect the same host cell. This process results in major antigenic ____ that are responsible for pandemics and epidemics of influenza A
reassortment
shifts
what is the cause of McArdle disease and how might it present
deficiency of muscle glycogen phosphorylase (no glycogenolysis)
adolescence or early adulthood with muscle pain, weakness, and decreased exercise tolerance (may have second wind effect due to increased blood flow during exercise)
What are the effects of Pineal tumor (pinealoma)
parinaud syndrome due to mass effect on the dorsal midbrain in the superior colliculus region:
upward gaze palsy
absent pupillary light reflex
impaired convergence
In a cirrhotic liver, what cell type primarily makes up the nodules which are separated by bridging fibrous septae
hepatocytes
What accumulates intracellularly and can be seen histologically in Parkinsons and Alzheimers
Lewy bodies: intraneuronal accumulation of alpha-synuclein and ubiquitin
Moxifloxacin MOA
fluroquinolone
Cystic hygromas are most commonly associated with when type of genetic abnormalities
chromosomal aneuploidy (Turner, trisomies) (cystic hygromas = soft, compressible masses that transilluminate; they are cystic lymphatic malformations)
inappropriate sexual activity, oral fixation, hyperphagia, visual agnosia, aphasia, placidity, and amnesia are all manifestations of what syndrome due to damage in what region of the brian
Kluver-Bucy syndrome
bilateral damage to temporal lobes particularly the amygdalae
How do calcineurin inhibitors, such as tacrolimus and cyclosporine, mediate their immunosuppressive effects
activated calcineurin normally dephosphorylates NFAT which allows it to enter the nucleus and bind IL-2 gene promoter
calcineurin inhibition –> inhibits IL-2 gene transcription
How do antipsychotics cause tardive dyskinesia
long term blockade of dopamine receptors –> upregulation and supersensitivity of dopamine receptors
what are possible presentations of dopamine beta hydroxylase deficiency
impaired sympathetic actiity due to impaired synthesis of NE and epi: hypotension pstosis hypothermia postural (orthostatic) hypotension exercise intolerance nasal congestion ejaculatory difficulties
How does an acute, massive pulmonary embolism (saddle embolism) effect the following:
central venous pressure
cardiac output
systemic vascular resistance
central venous pressure: increased (impaired forward blood flow)
cardiac output: decrease (reduced LV preload)
systemic vascular resistance: increase (body attempting to maintain adequate tissue perfusion and pressure)
What are 2 ways women can be more susceptible to X linked disorders
monosomy X (Turner syndrome) skewed X inactivation
what type of virus is adenovirus
naked, double stranded DNA
describe how dsDNA viruses (except pox virus) replicate
enters nucleus
protein capsid is degraded
dsDNA is released
host DNA dependent DNA polymerase facilitates replication of viral genome within host nucleus
eosinophilic cytoplasmic inclusions seen on brain biopsy are pathognomonic for what infection
rabies
what is the equation for filtration fraction of the kidneys
GFR/RPF
What cells are responsible for the pathogenesis of psoriasis
dendritic cells and T helper cells
Aminoglycosides are often used in combination with cell wall inhibitors to treat gram _____ infections
positive
cannot penetrate thick cell walls
orlistat MOA
inhibits intestinal lipase –> decreased intestinal fat absorption
venous drainage of the rectum above the dentate line occurs through the ____ veins, which drains into the portal venous system via the ______ vein. Structures below the dentate line drain into the _____ veins which drain into the systemic circulation via the ____ vein
superior rectal
inferior mesenteric
middle and inferior rectal veins
internal iliac
how do insulin and glucagon affect activation of PFK2/F-2,6-BPase
insulin activates PFK2 –> increased F-2,6-BP –> PFK1 stimulation –> glycolysis
glucagon activates F-2,6-BPase
Cell surface receptors with 7 alpha helical transmembrane domains are typically what?
G protein coupled receptors
The transmembrane domains of any protein are made up of what type of amino acids
hydrophobic
What structures pass through or within the walls of the cavernous sinus
CN III, IV, V(1 and 2), VI
internal carotid artery
How does mumps cause loss of labido
orchitis –> seminiferous tubule atrophy and Leydig cell atrophy –> infertility and decreased testosterone production
Why is probenecid used as combo therapy with other medications
blocks organic anion transporters on renal tubular cells to inhibit tubular secretion of certain antibiotics –> enhances efficacy
____ deficiency presents in an adolescent as elevated blood pressure, hypokalemia, low cortisol
17 alpha hydroxylase
will also have primary amenorrhea and lack of secondary sexual characteristics in females and ambiguous genitalia in boys
What physiologic changes cause situation syncope/reflex syncope
increased parasympathetic signaling and decreased sympathetic signaling:
arterial and venous dilation –> decreased systemic BP and venous return to heart
decreased heart rate and contractility –> decreased cardiac output
What condition is characterized by impaired nucleotide excision repair resulting in photosensitivity, increased pigmentation, dry skin, and increased risk of cutaneous malignancies
xeroderma pigmentosum
what are the translocations associated with each of the following: Burkitt lymphoma follicular lymphoma mantle cell lymphoma marginal zone lymphoma
Burkitt: t(8;14)
Follicular: t(14;18)
Mantle: t(11;14)
marginal: t(11;18)
what gene is overexpressed in each of the following: Burkitt lymphoma Diffuse large Bcell lymphoma follicular mantle
Burkitt: c-myc
Diffuse B cell: BCL-2
follicular: BCL2
mantle: cyclin D1
A homeless person presents with several small skin lesions on his trunk, face, and upper arms. They are red in color and contain multiple dilated blood vessels radiating from a single central vessel under close inspection. What are these and why are they present in this patient
spider angiomata
seen in hyperestrogenemia: pregnancy, cirrhosis
or in severely malnourished individuals
what % of the values will lie with with 1, 2, and 3 standard deviations of the mean
68
95
99
A 22 yr old female with severe pelvic pain during menses that is minimally relieved by NSAID. Laproscopy shows thin, filmy, adhesions throughout the pelvis, nodular implants in the posterior cul-de-sac and throughout the uterosacral ligaments. Several blue papules are found on the bladder and a 4 cm mass is seen in right ovary. What is the diagnosis
endometriosis
(lesions are typically blood-tinged and look like dark red, blue, or black papules: “powder burn lesions”.)
(lesions in the ovary can cause a blood-filled ovarian mass: endometrioma)
(recurrent endometrial shedding introduces blood into intraperitoneal cavity which leads to abdominopelvic inflammation and fibrosis —> infertility)
What is the purpose of coating a stent in everolimus
cytostatic drug –> inhibits mTOR therefore blocking cell cycle –> reduces smooth muscle cell proliferation
tight fitting, high knee boots can cause decreased sensation along the lateral right leg and dorsal right foot as well as prevent ability to walk on heels by damaging what nerve
common peroneal (superficial peroneal nerve may result in sensory loss over lateral leg and dorsolateral foot, however, foot drop is not expected as the anterior compartment muscles of the lower leg are not affected)
What cause of lethargy, hypotonia, emesis, and seizure will show increased urinary orotic acid
ornithine transcarbamylase (OTC) deficiency
Describe how a pre-pro-alpha chain becomes collagen
pre-pro-alpha chain has hydrophobic AA sequence that facilitates ribosomal binding to the RER
inside RER the signal is cleaved –> pro-alpha chain
proline and lysine residues hydroxylated by prolyl hydroxylase and lysyl hydroxylase which requires vit C
hydrogen bonds form resulting in triple helical procollagen
secreted from the cell
N and C terminal cleave by procollagen peptidase –> tropocollagen–> spontaneously form into fibrils which then crosslink –> collagen fibers
what is the result of a cingulate/subfalcine hernia
herniation under the falx cerebri
compression of anterior cerebral artery -> lower extremity weakness and sensation loss
what is the result of a central/downward transtentorial herniation
caudal displacement of brainstem –> rupture of paramedian basilar artery branches –> Duret hemorrhages (usually fatal)
what is the result of an uncal transtentorial herniation
(uncus = medial temporal lobe)
ipsilateral blown pupil (CNIII compression)
contralateral hemiparesis
coma
what is the result of cerebellar tonsillar herniation into the foramen magnum
compression of PCA –> contralateral homonymous hemianopsia
coma and death result when these herniations compress the brain stem
sacubitril MOA
neprilysin inhibitor –> increase in circulating ANP and BNP
compare the joint involvement of osteoarthritis and rheumatoid arthritis in the hand
osteo: DIP, PIP, and 1st CMC
RA: PIP and MCP
what are 3 manifestations that characterize VHL disease
hemangioblastomas
pheochromocytoma
renal cell carcinoma
What are Kayser-Fleischer rings, which are present in Wilsons disease
asymptomatic, brown or gray-green rings of fine granular copper deposits within the Descemet membrane of the cornea
The first step in oxidative burst pathway is catalyzed by ______ which forms ______. This molecule can directly damage the bacterial membrane through lipid peroxidation or it may spontaneously react with water to form hydrogen peroxide.
NAPH oxidase
superoxide
Fusions of azurophilic granules with the peroxisome introduces _____ which produces ____ which is many times more potent and destructive agent than hydrogen peroxide
myeloperoxidase hypochlorous acid (bleach)
What is the likely diagnosis of a single mobile, nontender mass in a 24 yr old pregnant woman which decreases in size after delivery
fibroadenoma
fibrocystic changes usually present as multiple bilateral nodules
What effect does Flumazenil have on barbiturates vs bensodiazepines
Flumazenil competitively inhibits benzodiazepines but not barbiturates at the GABA receptor complex
What make up each portion of the brain: prosencephalon telencephalon diencephalon mesencephalon thrombencephalon metencephalon myelencephalon
prosencephalon = telencephalon + diencephalon rhombencephalon = metencephalon + myelencephalon
telencephalon: cerebral hemispheres and lateral ventricles
diencephalon: thalamus and 3rd ventricle
mesencephalon: midbrain and aqueduct
metencephalon: pons, cerebellum and upper 4th ventricle
myelencephalon: medulla and lower 4th ventricle
What protein contains a 30-aminoacid helical segment that consists of repeated leucine residues at every seventh position
leucine zipper
Carbamoyl phosphate synthetase II is an enzyme that catalyzes the initial step in _____. Where is it located?
de novo pyrimidine synthesis
cytosol
Carbamoyl phosphate synthase I is an enzyme in what pathway? Where is it located in the cell?
urea cycle
mitochondria
When asking a patient to flex the hip against resistance applied by the examiner at the anterior knee, a positive test (elicited pain) indicates what 2 possibilities?
inflammation of the psoas muscle or its overlying peritoneum (appendicitis)
Alcohol-induced cardiomyopathy is a ___ cardiomyopathy
dilated
A complete mole is distinguished from a partial mole by ____ staining negative
p57
(p57 protein is the product of a paternally imprinted but maternally expressed gene, therefore, complete moles are p57 negative)
A complete mole occurs due to abnormal proliferation of what cells
placental precursor cells: cytotrophoblasts and syncytiotrophoblasts
What is seen on ultrasound of a complete mole
snow storm: central heterogenous mass in the uterus with numerous discrete anechoic spaces
How are retinoids (vitamin A analogues) able to prevent comedone (acne) formation
normalization of keratinization
decreased epithelial cohesiveness
stimulated stem cell mitosis (increased epithelial turnover)
The esophagus passes through the esophageal hiatus with what other structure
vagus nerve
The aorta passes through the aortic hiatus of the diaphragm with what other structures
thoracic duct
azygos vein
What is Maturity-onset diabetes of the Young (MODY)?
AD disorder
mutations in glucokinase gene or associated transcription factors –> impaired insulin secretion with minimal or no defects in insulin action
(glucokinase –> glycolysis –> increased insulin release)
A 5 mo old patient experiencing seizures and hepatomegaly (enlarged abdomen) has a low blood glucose. Administration of fructose syrup results in lactic acidosis without increasing blood glucose level. What is the diagnosis
von Gierke disease
glucose-6-phosphatase deficiency
An elderly man with sepsis that develops venipuncture site and urinary tract bleeding indicates what diagnosis?
disseminated intravascular coagulation
Are the following increased or decreased in DIC: fibrinogen PTT PT platelets D-dimer
fibrinogen: decreased
PT and PTT: increased
platelets: decreased
D- dimer: increased
How do salmonella and E. coli differ when on Hektoen enteric agar?
salmonella: becomes black bc produces hydrogen sulfide while E. coli does not (green)
A hemorrhage occurring where typically causes pinpoint pupils, loss of horizontal gaze, quadriparesis, decerebrate posturing, and rapidly evolving coma
pons (pontine hemorrhage)
How can neoplastic lesions cause increased intracranial pressure (beside themselves adding mass)
disrupt the blood brain barrier –> increased vascular permeability –> vasogenic edema
and
obstruction of normal cerebrospinal fluid flow
What cells types are present at the cervical transformation zone
simple columnar epithelium (vagina and ectocervix)
simple columnar epithelium (endocervix)
What medication inhibits mycolic acid synthesis in TB treatment
isoniazid
What antibiotics perform their antibiotic actions by binding transpeptidases
penicillins and cephalosporins (transpeptidases are penicillin binding proteins)
what are the manifestations of secondary syphilis
diffuse rash (palms and soles) lymphadenopathy condyloma latum oral lesions hepatitis
Describe the mechanism of isopropanol as a disinfectant
disrupts the cell membranes and denatures proteins
describe the mechanism of chlorhexidine’s as disinfectant
disruption of cell membranes
coagulation of cytoplasm
describe the mechanism of hydrogen peroxide as a disinfectant
produces destructive free radicals that oxidize cellular components
describe the mechanism of iodine as a disinfectant
halogenation of proteins and nucleic acids
What should be added when testing sputum culture for a CF patient with pneumonia in addition to regular agar (strep), chocolate (H. flu), MacConkey (pseudomonas), and mannitol salt agar (S aureus)
Agar selective for Burkholderia cepacia complex (a fastidious gram negative bacterium that is often difficult to eradicate and associated with increased morbidity and mortality)
In HIV, the ___ gene encodes polyprotein ___, which is extensively glycosylated in the ER and Golgi body and cleaved into what proteins with what functions
env
gp160
gp120: mediates viral attachment
gp41: mediates fusion (transmembrane protein)
What contact precautions are required for any contact with a patient with C. Dif
handwashing with soap and water
gown
gloves
(private room preferred)
What are 2 ways campylobacter can be aquired
contaminated food (undercooked poultry) domesticated animals (household dogs)
What are 4 causes of diarrhea that only require a small inoculum to produce symptoms (500 cells or less)
shigella
campylobacter
entamoeba histolytica
giardia lamblia
What is the cause of pol gene mutations arising in HIV
inconsistent use of antiretroviral therapy
(many of them target pol gene proteins: protease inhibitors, reverse transcriptase inhibitors, and integrase strand transfer inhibitors)
What allows typhoid salmonella to produce a systemic effect while nontyphoidal salmonella stays localized to the GI tract
capsular antigen vi –> extensive intracellular replication in macrophages –> spread through lymphatics and RES
Why should fluoroquinolones not be taken with antacids
fluoroquinolones can form insolube chelate complexes with polyvalent cations in GI leading to impaired absorption
over the counter antacids contain calcium, magnesium or alumium salts
(also seen in patients taking calcium salts for osteoporosis)
What is the the biggest contributor to increased occurrence of nosocomial blood stream infections with s. aureus
intravascular catheters
What is a cause of ulcers in the colon that display inflammatory infiltrate, mucosal necrosis, and enlarged endothelial cells with large, ovoid nuclei containing prominent basophilic deposits and is only seen in immunocompromised patients
CMV
HIV Protease inhibitors inhibit ___ (host or viral) protease from cleaving the ____ polyprotein products
viral
gag-pol
(results in formation of immature noninfectious virons due to impaired production of functional viral proteins)
Which strain of HIV can be treated with maraviroc and why, R5 strains or X4?
R5: they attach to host CD4 receptor and CCR5 chemokine coreceptor so CCR5 inhibitors (maraviroc) can be used
(X4 bind CD4 and CXCR4 chemokine receptor so maraviroc cannot be used)
What type of virus is Hep E? (single/double strand; RNA/DNA, enveloped/naked)
unenveloped, single stranded RNA virus
The most concerning feature of hepatitis E infection is the high mortality rate in what population
pregnant women
Patients with long term IUDs are at increased risk for developing an active ___ infection which can cause pelvic inflammatory disease and appears as acute-angle branching, gram positive bacilli
actinomyces
What is the target for trimethoprim, methotrexate, and pyrimethamine?
they all inhibit dihydrofolate reductase
trimethoprim in bacteria, methotrexate in human cells, and pyrimethamine in some protozoa
What is the leading pathogen in adults with CF, which forms a thick biofilm to prevent its full elimination from the body
pseudomonas aeruginosa
Describe the Strep Pneumo vaccine given to children
conjugate vaccine (T cell dependent response --> long lasting immunity) that is 13 valent polysaccharides from 13 serotypes conjugated to recombinant diptheria toxin
What is the treatment for Diptheria
diptheria antitoxin + antibiotic therapy (penicillin or erythromycin)
Penicillins are structurly similar to what?
D-alanine-D-alanine
inhibit transpeptidase by binding covalently to its active site
What is responsible for the conversion of nonpathogenic Cornybacterium into toxigenic Cornybacterium which is responsible for elaborating th e diphtheria exotoxin which causes pseudomembranous pharyngitis and potentially life threatening side effects
lysogenic bacteriophages (Corynephage beta inserts tox gene into the C diphtheriae genome which results in bacterial expression of diphtheria AB toxin)
what 2 antifungal medications bind ergosterol molecules in the fungal cell membranes, creating pores and causing cell lysis
amphotericin B
nystatin
What infection is common in patients with advanced AIDs causes nonspecific symptoms, lymphadenopathy, and hepatosplenomegaly and the diagnosis often being made on blood culture or bone marrow aspirate showing intracellular acid fast bacteria that are not TB
mycobacterium avium
What is a spore-forming, exotoxin-producing, gram-positive organism that is the most common cause of spontaneous (non trauma induced) gas gangrene? what is the greatest risk factor for it?
clostridium septicum
colonic malignancy
What is the organism almost always implicated in hot tub folliculitis?
pseudomonas aeruginosa
What changes to the colon are made by rotavirus resulting in water diarrhea without fecal leukocytes
infect villous enterocytes in the duodenum and proximal jejunum and results in villous blunting, proliferation of secretory crypt cells, and loss of brush border enzymes
What is the infecting organism that causes fever, nausea, vomiting, watery diarrhea and myalgias that is gram positive rods
listeria
what are listerias virulence factors
listeriolysin O: generates pores in phagosome membranes
actin based transcellular spread: hijacks the actin-based cellular motility mechanism of host cells
What is the function of diphtheria AB exotoxin
ribosylates and inactivates elongation factor-2 which inhibits protein synthesis and ultimately leads to cell death
