Pathoma Flashcards
Genetic disease associated with Apo-E allele mutation
Late set Alzhemiers
Disease caused by Amyloid precursor protein, presenilin 1 gene on chromosome 14, presenilin 2 gene on chromosome 1
Early onset Alzheimers
There is a killed (Salk) and live (Sabin) vaccine against the polio virus. Which one is better at prolonged synthesis and secretion of local mucosal IgA?
Live virus
What kind of test is used to compare the means of 2 groups of subjects?
Two-sample T-test
What does acetylcholinesterase in the amniotic fluid typically indicate?
Failed fusion (Neural tube defect) Note: Alpha-fetoprotein (AFP) in the amniotic fluid suggests the same thing. Lack of close of the neural tube allows for these things to leak out into the amniotic fluid.
TLR found on macrophages that recognizes the PAMP (lipopolysaccharide) on the outer membrane of gram negative bacteria.
CD-14
TLR activation results in upregulation of ______, a nuclear transcription factor that activates immune response genes leading to production of multiple immune mediators.
NF-kappaB
Enzyme that causes arachidonic acid release from the phospholipid cell membrane.
Phospholipase A2.
Remember, AA precursor of prostaglandins and thromboxanes (via cyclooxygenase COX) or leukotrienes (via 5-lipooxygenase).
What function do the prostaglandins PGI2, PGD2, and PGE2 have?
They all three mediate vasodilation and increased vascular permeability.
Note: PGE2 also causes fEver and pain.
What type of immune cells will you find toll-like receptors?
innate immune cells (macrophages and dendritic cells).
What type of leukotriene will attract and activate neutrophils?
LTB4
Note: C5a (complement), IL-8 and bacterial products also attract and activate neutrophils.
Which type of leukotrienes will contraction of smooth muscle (vasoconstriction and bronchospasm), as well as increased vascular permeability?
LTC4, LTD4, and LTE.
What type of cell is activated by one of these three methods:
- Tissue trauma
- Complement proteins C3a and C5a
- Cross linking the cell surface IgE by antigen
Mast cells-which are widely distributed throughout connective tissue.
Note: when they are activated, they release preformed histamine granules, which mediate vasodilation of the arterioles and increased vascular permeability.
Three ways to activate complement are:
Classical pathway
Alternative pathway
Mannose-binding lectin pathway
What is each ones of these about?
- Classical: C1 binds IgG or IgM that is bound to antigen.
* ***Mneumonic: GM makes classic cars. - Alternative: microbial products directly activate complement.
- MBL: MBL binds to mannose on microorganisms, which activates complement.
All complement pathways result in production of C3 convertase (mediates C3–>C3a and C3b), which in turn produces C5 convertase (mediates C5–>C5a and C5b). C5b complexes with C6-C9 to form the membrane attack complex (MAC).
What do the following cause to happen:
- C3a and C5a
- C5a
- C3b
- Mac
- C3a & C5a: anaphylatoxins: trigger mast cell degranulation, resulting in histamine-mediated vasodilation and increased vascular permeability.
- C5a: Chemotaxis for neutrophils
- C3b: Opsonin for phagocytes
- MAC: Lyses microbes by creating a hole in the cell membrane.
Inactive proinflammatory protein produced in the liver which is activated upon exposure to subendothelial or tissue collagen, which in turn activates:
- Coagulation of fibrinolytic systems
- Complement
- Kinin System—>cleaves kininogen to bradykin, which mediates vasodilation and increased vascular permeability (similar to histamine), as well as pain
Hageman Factor (Factor XII)
What are the five cardinal signs of inflammation?
- Redness (rubor)
- Warmth (calor)
- Swelling (tumor)
- Pain (dolar)
- Fever
In inflammation, rubor and calor (redness and warmth) are due to vasodilation, which results in increased blood flow. What are the key mediators of this?
Histamine, Prostaglandins (PGI2, PGD3, and PGE2), and bradykinin.
Inflammation during swelling occurs due to leakage of fluid from POSTCAPILLARY venues into the interstitial space (exudate). What are are the key mediators?
- Leukotrienes: cause endothelial cell contraction.
2. Tissue damage: results in endothelial cell disruption
You will see pain (dolar) involved with inflammation. What mediates this pain?
Bradykinin and PGE2 sensitize sensory nerve endings.
Macrophages are responsible for fever during inflammation. This occurs when pyrogens (LPS from bacteria) cause macrophages to release ________ and _________, which increase COX activity in per vascular cells of the hypothalamus, resulting in PGE2, which raises the temp set point.
IL-1 and TNF
In acute inflammation, you will neutrophils will:
- Marginate (due to vasodilation)
- Roll
- Adhere
- Transmigrate and chemotax
- Phagocytose
What causes the rolling?
P-selectin (released from Weibel-Palade bodies–>from histamine)
E-sectin (induced by TNF and IL-1)
Remember TNF and IL-1 are released from macrophages and also cause fever.
In acute inflammation, you will neutrophils will:
- Marginate (due to vasodilation)
- Roll
- Adhere
- Transmigrate and chemotax
- Phagocytose
- What are the molecules that cause cellular adhesion?
- What molecules cause the upregulation of these adhesion molecules?
- ICAM and VCAM: on endothelium upregulated by TNF and IL-1.
- Integrin: on leukocytes upregulated by C5a and LTB
Interaction between the CAMs and Integrins result in firm adhesion of leukocytes to the vessel wall.
Autosomal recessive defect of integrins (CD18 subunit)
**Clinical features include delayed separation of umbilical cord, increased circulating neutrophils, and recurrent bacterial infections that lack pus formation.
LAD: Leukocyte adhesion deficiency
In acute inflammation, you will neutrophils will:
- Marginate (due to vasodilation)
- Roll
- Adhere
- Transmigrate and chemotax
- Phagocytose
What two opsonins are important in phagocytosis of pathogens or necrotic tissue?
IgG
C3b
Autosomal recessive protein trafficking defect (caused by microtubule defect) characterized by impaired PHAGOLYSOSOME FORMATION.
Characterized by:
-Increased risk of pyrogenic infection-
Neutropenia (due to intramedullary death of neutrophils)
-Giant granules in leukocytes (due to fusion of granules arising from the Golgi)
-Defective primary hemostasis (due to abnormal dense granules platelets).
-Albinism (pigment can’t move into keratinocytes).
-Peripheral neuropathy (can’t traffic protein from nerve to nerve ending distally).
Chediak-Higashi syndrome
What is the most effective method of phagocytosis?
O2-dependent killing.
(HOCL- generated by oxidative burst in phagolysosomes destroys phagocytosed microbes.
Name that enzyme:
- O2 —->O2-
- O2—->H2O2
- H2O2—->HOCL- (bleach): found in lysosomes in neutrophiles
- NADPH oxidase (oxidative burst)
- superoxide dismutase (SOD)
- Myeloperoxidase (MPO)
- Disease caused by NADPH oxidase defect (so no O2—>O2—->H2O2—>HOCl-). It is either X-linked or autosomal recessive). Leads to recurrent infection and granuloma formation with catalase-positive organisms.
- Two catalase-+ organisms that are typically recurrent in this diease.
- Chronic granulomatous disease (CGD)
2. S. aureus, PSEUDOMONAS CEPACIA.
Chronic granulomatous disease (CGD) is characterized by poor O2 dependent killing and is typically due to NADPH oxidase defect. What test is used to screen for CGD?
Nitroblue tetrazolium test-
Leukocytes are incubated with NBT dye, which turns blue if NADPH oxidase can convert O2 to O2- but remains colorless if NADPH oxidase is defective.
What is the difference between chronic granulomatous disease and MPO deficiency?
Chronic granulomatous disease: NADPH oxidase deficiency-positive NBT (nitroblue terazoium test…will be clear results). No O2 to O2-.
Myeloperoxidase deficiency: defective conversion of H2O2 to HOCl- INCREASED RISK OF CANDIDA INFXN.–>NBT test will turn blue (b/c NAPDH oxidase is fine).
What happens to neutrophils after resolution of infection?
Apoptosis within 24 hours after resolution of inflammatory stimulus.
In acute inflammation, neutrophils will be on the scene first. But macrophages predominate after neutrophils and peak 2-3 days after inflammation begins. They arrive in the tissue the same way neutrophils do.
After macrophages ingest organisms via phagocytosis, how do they kill them?
O2 INDEPENDENT killing: use enzymes in secondary granules (such as lysozyme).
Macrophages manage the next next of inflammatory process (after neutrophils). They can facilitate:
- Resolution and healing.
- Continued acute inflammation (IL-8 recruits more neutrophils)
- Abscess (macrophages mediate fibrogenic growth factors and cytokines)
- Chronic inflammation: macrophages present antigen to activate CD4+ helper T cells, which secrete cytokines that promote chronic inflammation.
What are the anti-inflammatory cytokines that cause resolution and healing after an acute inflammation?
- IL-10 and TGF-beta
Progenitor T-cells are formed in the bone marrow, but are further developed in the thymus where the T-cell receptor (TCR) undergoes rearrangment and becomes CD4+ helper T-cells or CD8+ cytotoxic T cells.
Which MHC do CD4+ t-cells recognize?
Which MHC do CD8+ t-cells recognize?
- CD4+ (Helper T’s): MHC II
- CD8+ (Cytotoxic T’s): MHC I
Remember MHC II is antigen from outside of the cell (bacteria, for example.
MHC I is antigen from inside of the cell (either self antigen or viral antigen).
Activation of T-cells require two steps:
- Activation of antigen/MHC complex.
2 Additional signal. - In the case of CD4+ T-cells, they will bind MHC II. What is the second step in activation?
- In the case of CD8+ T-cells, they will bind MHC I. What is the second step in activation?
- B7 (antigen presenting cells)—>binds CD28 (on CD4+ helper T’s).
- IL-2 from CD4+ helper T’s is the second step in activation of CD8+ cells.
CD4+ T-Helpers can be divided into two categories:
TH1
TH2
What do each of these types of cells “help”?
TH1: stimulates CD8+ T-cells (via T-cell growth factor) and macrophages (via IFN-gamma.)
TH2: stimulates B-cell class switching to IgG and IgE via IL-4, eosinophil chemotaxis and activation, as well as maturation of B cells to plasma cells and class switching to IgA via IL-5, as well as secrete IL-10 (which inhibits TH1 phenotype).
How do cytotoxic T-cells kill? (2 ways)
- Secretion of perforin and granzyme; perforin creates pores that allow granzyme to enter the target cell, activating apoptosis.
- Expression of FasL, which bind to Fas on target cells, activating apoptosis.
Immature B cells are produced in the bone marrow and undergo immunoglobulin rearrangements to become naive B cells that express surface IgM and IgD. What two ways does B-cell activation occur?
- Antigen binds surface IgM or IgD, resuling in maturation to IgM or IgD-secreting plasma cells.
- B-cell antigen presentation to CD4+ helper T-cells via MHC class II.
B lymphocytes are activated either by antigen binding surface IgM or IgD which results in a IgM or IgD plasma secreting cell OR a B-cell antigen presentation to CD4+ helper T’s via MHC Class II.
If the activation occurs in the latter way, what else has to happen to activate the B-cell after it presents antigen to the Th2 cell?
CD40 R (on Bcell) binds CD40L (on T cells), providing the second activation signal.
*Helper T then secretes IL-4 and IL-5, which mediates B-cell isotype switching, hypermutation, and maturation into plasma cells).
A collection of epithelioid histiocytes (macrophages with abundant pink cytoplasm, usually surrounded by giant cells and a rim of lymphocytes.
Granuloma.
Common etiologies include reaction to foreign material, sarcoiosis, beryllium exposure, Crohn disease, and cat scratch disease
Non-caseating granulomas (lack central necrosis)
Tb and fungal infections cause this
Caseating granulomas (central necrosis)
What do macrophages secrete that induce CD4+ helper T cells to differentiate into TH1 subtype?
IL-12
What do Th1 cells secrete, which will convert macrophages into epithelioid histiocytes and giant cells which characterize granulomas?
IFN-gamma
Present with T-cell deficiency (lack of thymus), hypocalcemia (lack of parathryoid hormone), abnormalities of heart, great vessels and face.
DiGeorge Syndrome (22q11 microdeletion): developmental failure of the 3rd and 4th pharyngeal pouches.
Characterized by defective T-cell and B-cell immunity which results from adenosine deaminase (ADA) deficiency.
SCID: Since ADA is necessary to deaminiate adenosine and deoxyadenosine for exretion as waste products, buildup of adenosine and deoxyadenosine is toxic to lymphocytes.
X-linked disease caused by mutated Bruton tyrosine kinase
Presents with recurrent bacterial, enterovirus and Giardia lamblia infections after 6 months of age.
x-linked agammaglobulinemia: disordered B cell maturation.
Avoid live vaccinations
Remember that there is no antibody to opsinize the bacteria, and no IgA to protect the mucosa (enterovirus and Giardia affect GI tract).
Common variable immunodeficiency (CVID) is characterized by low Ig due to B-cell or T-cell defects. There is an increased risk for bacterial, enterovirus and Giardia infections.
What disorders does having CVID increase the risk of?
Autoimmune and lymphoma
Most common immunoglobulin deficiency.
IgA: increased risk for mucosal infection, esp. viral; however, most patients are asymptomatic.
Hyper IgM syndrome is caused by _______.
Mutated CD40L (on helper T cells) or CD40 (on B cells).
Second signal can not be delivered to helper T cells during B-cell activation. Consequently, cytokines necessary for Ig class switching are not produced.
Low IgA, IgG, and IgE result in recurrent pyogenic infections, due to poor opsonization, esp. at mucosal sites.
Characterized by thrombocytopenia (increased bleeding), eczema, and recurrent infections (defective humoral and cellular immunity)
Wiskott-aldrich syndrome: due to mutation in the WASP gene (X-linked)
What do C5-C9 deficiencies increase the risk for?
Neisseria infection (gonorrhea and meningititis)
What will C1 inhibitor deficiency result in?
Hereditary angioedema (edema of skin and mucosal surfaces).
Nothing to inhibit complement.
Sjogren’s cancer association
B-cell lymphoma
Suspect if patient has unilateral growth of parotid.
SLE: characterized by ANA (sensitive but not specific). What antibody is specific?
Anti-ds DNA
Drug-induced lupus antibody
Antihistone antibody
Drugs that cause are hydralazine, procainamide, and isoniazid. Removal of drugs = remission of symptoms.
SLE can lead to false + syphillis test and falsely elevated PTT labs. Why?
Antiphospholipid antibody syndrome, where you have:
Anticardiolipin and lupus anticoagulant.
1 of death in lupus patients
Diffuse proliferative glomerulonephritis
Sjogren’s syndrome is lymphocyte mediated damage (type IV hypersensitivity) with fibrosis. Dry eyes, dry mouth because autoimmune destruction of lacrimal glands.
Characterized by ANA and anti-SSA and anti-SS-B. What is the target of these two anti-bodies?
Ribonucleotide proteins.
Sjogren’s is associated with other AI disorders. Which one is most common?
RA
Scleroderma is an disorder characterized by autoimmune tissue damge with activation of fibroblasts and deposition of collagen (fibrosis). Along with ANA, you will have Scl-70 antibody. What is this antibody against?
DNA topoisomeriase
What is crest syndrome?
Type of localized scleroderma.
Crest:
Calcinosis Reynaud's Phenomenon ESOPHAGEAL DYSMOTILITY Sclerodactyly Telangectasia
Note: Has Anti-Centromere antibody
If you see features of SLE, systemic sclerosis, and maybe a little bit of polymyositis mixed together, what kind of serum antibodies will you look for to help make a dx of mixed connective tissue disease?
anti-U1 ribnonuceloprotein antibodies.
There are 3 types of wound healing based on tissue regenerative capacity.
- Labile tissues: constant regeneration
- Stable tissues: Have quietscent G0 cells that can reenter the cell cycle to regenerate when necessary
- Permanent tissues: lack significant regenerative capacity.
What type of tissues fall in each?
- Labile:
Skin (basal cell stem cells)
Small and large bowel (stem cells in mucosal crypts
Bone marrow (hematopoietic stem cells. - Stable:
Liver regeneration by compensatory hyperplasia after partial resection. - Permanent: myocardium, skeletal muscle and neurons.
During wound healing, when will you get repair rather than replacement?
Repair is replacement of damaged tissue with a fibrous scar.
It occurs when regenerative stem cells are lost (deep skin cut) or when a tissue lacks regenerative capacity (after myocardial infarction).
During wound healing, when regeneration can’t occurs and repair must happen, granulation tissue occurs first. What does granulation tissue include (3 things)?
Fibroblasts (depositis type III collagen)
Capillaries (provides nutrients)
Myofibroblasts (causes wound contraction)
Note: Type III collagen will be eventually replaced with Type I collagen via collagenase (with zinc cofactor).
Type 1 collagen includes:
bONE
skin
tendons
most organs
Type III collagen includes:
Remember, it is pliable, so it includes:
Blood vessels, granulation tissue, embryonic tissue
Type II collagen includes:
CarTWOlidge
cartilage
Type IV collagen is found in the:
basement membrane
Keloids are formed from what type of collagen
Type III (pliable)–>remember type III is the type used in the initial granulation tissue of wound repair.
Enzyme used to catalyze reaction from TYPE III to Type I collagen in wound repair? What is needed as cofactor of this enzyme?
Collagenase (needs zinc as a cofactor)
Tissue regeneration and repair is mediated by paracrine signaling via growth factors. The growth factor interaction with its receptor will result in gene expression and cellular growth. Here are a few examples:
TGF-alpha TGF-beta PDGF: Fibroblast growth factor VEGF
Which of these is:
- an important fibroblast growth factor while also inhibiting inflammation?
- Important in angiogenesis?
- TGF-B (remember that when macrophages secrete this, they call off the acute inflammation and start the healing response).
- Fibroblast Growth Factor and VEGF are both important in angiogenesis.
What is the difference between primary and secondary intention when relating to cutaneous healing??
- Primary intention: wound edges are brought together (suturing of a surgical incision); leads to minimal scar formation.
- Secondary intention: edges are not approximated. Granulation tissue (fibroblasts, capillaries, and myofibroblasts), then a scar forms.
You would have delayed wound healing with infection, vitamin C, copper and zinc deficiencies as well.
Why would vitamin c, copper and zinc deficiencies cause delayed healing?
- Vitamin C:cofactor for hydroxylation of proline and lysine procollagen residues. This hydroxylation is necessary for eventual collagen cross-linking.
- Cooper: cofactor for lysyl oxidase, which cross-links lysine and hydroxylysine to form stabile collagen.
- Zinc is cofactor for collagenase, which replaces Type III collagen with Type I.
Dihiscence
Rupture of a wound, most commonly seeen after abdominal surgery.
What is the difference between a hypertrophic scar and a keloid?
Hypertrophic scar is excess production of scar tissue that is localized to the wound. Keloid is excress scar tissue that is out of proportion to the wound (Excess type III collagen, AA, classically earlobes, face and UE).
Kallman Syndrome
Defective migration of GnRH cells and formation of olfactory bulbs; Decreased Synthesis of GnRH in hypothalamus; anosmia, lack of secondary sexual characteristics. Decreased GnRH, FSH, LH, testosterone and sperm count.
FA page 525
Three phases of gastric activity are cephalic, gastric and intestinal. Which phase(s) has/have increased gastric acid secretion and which have reduced?
Cephalic and gastric: increased (release of gastrin —>H+)
Intestinal phase reduces gastric acid secretion
When doing drug trials, how do you determine the Number Needed to Harm (NNH)?
Find attributable risk:
Event rate of treatment - Event rate of placebo.
NNH = 1/attributable risk
page 52 FA
In the final step of insulin synthesis, the pancreas B-cell cleaves away a portion of the proinsulin polypeptide chain, forming insulin. What happens to the other part of proinsulin that is cleaved from insulin?
C peptide is put in secretory granules with insulin and they are both secreted in eqimolar concentrations.
Pulmonary fibrosis is a restrictive lung disease whereas COPD and asthma are obstructive lung diseases. How do people breathe in each one (rate and depth)?
Restrictive lung disease: Rapid, shallow breaths.
Obstructive: slow, deep breaths
Obstructive of what vein will cause the following symptoms:
Right slided face and arm swelling
Engorgement of subcutaneous veins on the right side of the neck?
Right Brachiocephalic vein
Note: If symptoms were bilateral, this would be SVC Syndome.
Autosomal recessive disorder caused by a deficiency in the enzyme homogentisic acid oxydase, which causes arthritis and deposits in sclera and ear cartilage. Urine turns black when hits air.
Alkaptonuria: This enzyme normally breaks down the tyrosine byproduct homogentysic acid (also called alkapton). This acculated homogentesic acid causes pigment deposits in connective tissues throughout the body.
Name that pharyngeal pouch:
Epithelium of middle ear and auditory tube
1st pharyngeal arch
Name that pharyngeal pouch: thymus and inferior parathyroid glands
3rd arch
Name that pharyngeal arch:
Superior parathyroid glands, ultimobranchial body
4th pharyngeal arch
Myasthenia gravis is associated with abnormalities of the _____________.
thymus
What is the difference between suppression and repression as relates to coping skills?
Suppression: CONSCIOUS, mature defense mechanism involving troublesome thoughts or impulses.
Repression: UNCONSCIOUS removal of disturbing psychological material from conscious awareness.
What heart abnormality is associated with Downs Syndrome?
Endocardial cushion defects (Ostium primum ASD, regurgant atrioventricular valves)
Heart defect associated with DiGeorge Syndrome.
Tetrology of Fallot and interrupted aortic arch.
What heart defect is associated with Marfan Syndrome?
cystic medial necrosis of aorta.
Heart defect associated with Turner Syndrome:
Coarctation of the aorta.
What heart defect is associated with Tuberous sclerosis?
Valvular obstruction due to cardiac rhabdomyomas. (TS = benign tumors in a lot of different tissues including brain and kidneys).
Heart problems associated with Friedreich’s ataxia.
Hypertrophic cardiomyopathy.
What is defective in kertagener syndrome?
Dynein in the microtubules, which means so movement of cilia. Infertility, recurrent sinusitis and bronchiectasis result. Is associated with situs inversis.
Most common three cancers in women?
Breast, lung, colon
Note: When looking at mortality, it is in the following order: Lung, Breast, Colon
What is the best way to prevent neonatal tetanus?
Give maternal vaccine during pregnancy. This will allow the transfer of protective IgG antitoxin antibodies across the placenta.
What is the difference between brief psychotic disorder, schizophreniform disorder and schizophrenia?
The amount of times that symptoms last.
Brief psychotic disorder: < 1 month
Schizophrenifom: 1 month - 6 months
Schizophrenia: > 6 months
What happens if there is incomplete obliteration of the processus vaginalis?
You get indirect inguinal hernia (hernia through the deep inguinal ring, but not in the inguinal triangle as with direct hernia).
BUT, if you don’t have a herniation but still have incomplete obliteration, fluid can leak into the testicles causes hydrocele of the testicle.
Fetus with flat face, abnormal ears, slanted palpebral fissures, redundant skina t nape of neck, hypotonia, pelvic dysplasia and single transverse palmar crease.
Down Syndrome (Trisomy 21)
Microcephaly, low-set ears, prominent occiput and small mandible. Clenched fist and fingers overlap. What is it?
Trisomy 18 (Edwards Syndrome)
Cleft lip and palate, polydactyly and omphlocele
Trisomy 13 (patau syndrome)
How do you attempt to prevent acute organ rejection after a transplant?
Calcineurin inhibitors: cyclosporine and tacrolimus. If in active rejection, give steroids.
In the female reproductive tract, androgens and progesterone are synthesized from cholestrol in the theca interna. Where are these androgens converted to estradiol?
The granulosa cells have aromatase, which can convert androgens to estradiol. This occurs under the stimulation of FSH.
Polyhydramnios refers to excessive accumulation of amniotic fluid and is typically related to either decreased fetal swallowing of increased fetal urination. What fetal anomalies are associated with polyhydramnios?
Gastrointestinal obstruction due to duedenal, esophageal, or intestinal atresia and ANACEPHALY.
What causes Potter’s Syndrome?
Severe oligohydramnios. You will get renal a genesis and fetal compression by the uterus, which results in fetal deformities.
Connection observed at the apices of glandular cells and consist of two closely adherent cytoplasmic membranes without an intervening space. The first component of the junctional complex.
Tight junctions
Delicate network of cytplasmic filaments that radiate from teh cell membrane to hold adjacent cells together. They are the second component of the junctional complex.
Intermediate junctions
Small, circular, adherent patches circumferentially palced around cellst hat comprise the third component of the junctional complex. They are common in stratified squamous epithelium and contribute significantly to the structural cohesiveness of tissues subject to mechanical stressors.
Desmosomes
Extend from basal surfaces of keratinocytes in the stratified squamous epithelium to attach to the basal lamina.
Hemidesmosomes.
Osteocytes have long intracanalicular processes that extend through the ossified bone matrix. These processes send signals to and exchange nutrients and waste products wtihin the neighboring lamallae via _______________ junctions. Osteocytes can sense mechanical stresses and send signals to modulate the activity of surface osteoblasts, therby helping to regulate the bony remodeling.
Gap
In a normal bell-shaped distribution, what % falls within:
1 std
2 std
3 std
1: 68%
2. 95%
3. 99.7%
Chronic granulomatous disease is an X-linked disorder resulting in the deficiency of what enzyme?
What test is used to diagnose this disease?
- NADPH oxidase (O2 —> O2- can not be done, meaning that HOCL- can not be created to kill the bacteria in the neutrophil.)
- Nitroblue tetrazoium test: If it DOES NOT CHANGE COLOR, then there IS a deficiency of NADPH oxidase.
S. aureus has an enzyme on its surface that reacts with prothrombin , which results in converting fibrinogen to fibrin. This process is believed to result in fibrin-coating of the organsims and resistance to phagocytosis. What is the molecule on the surface of S. aureus?
Caoagulase
What is the enzyme produced by clostridium bacteria that is capable of destroying erythrocytes, platelets, leukocytes and endothelial cells? It is responsible for the necrosis observed in gas gangreen (closteridium myonecrosis).
Lecinthinase, also called Phospholipase C or alpha toxin
A promoter region that binds transcription factors and RNA polymerase II during initiation of transcription. It is located appx. 25 bases upstream from teh beginning of the coding region.
TATA box
Note: The other promoting codon is the CAAT box, which is loacted 60-80 bases upstream on the 5’ end of the coding region.
What is the purpose of DNA methylation?
To silence the gene it is affecting. It is part of the epigenetic code.
- ___________________ is produced by Sertoli cells and is the physiologic inhibitor of FSH secretion.
- LH concentration is primarily controlled by levels of what hormone?
- Inhibin B: FSH stimulates the release of inhibin B from the sertoli cells of the testes.
- Testosterone (also DHEA and dihydotestosterone)==>all part of the LH feedback inhibition loop. LH stimulates the release of testosterone from the Leydig cells of the testes.
CO binds to hemoglobin with a much higher affinity than O2, thus preventing O2 binding to hemoglobin. It also reduces teh unloading from hemoglobin into the tissues.
Does CO poisoning affect the PaO2, and does it precipitate methemoglobinemia?
- No: The PaO2 (partial pressure of oxygen dissolved in the plasma) does not change. It affects only the amount of oxygen that can bind to hemoglobin. Thus PaO2 in CO poisoning is normal.
No. Methemoglobin is formed with the Fe2+ (ferrous iron) in heme is oxidized to Fe3+ (ferric iron). This results from drug exposures (dapsone, nitrites), as well as enzyme deficencies and hemoglobinopathies.
- How does CSF get from the lateral ventricles to the third ventricle?
- From the third to the fourth ventricle?
- From the fourth ventricle to the subarachnoid space?
- Interventricular foramen of monroe (lateral to third)
- Cerebral aquaduct (third to fourth)
- Lateral foramina or Luschka or Medial foramen of Magendie (fourth to subarachnoid space).
* Note: CSF is returned to the venous circulation via the arachnoid villi (granulations)
No blockage to CSF flow within the brain or brainstem, but a blockage in the subarachnoid space where flow may be restricted by fibrosis following inflammation
Communicating hydrocephalus
Hydrocephalus where CSF is not absorbed by the arachnoid villi
Normal pressure hydrocephalus
Increased CSF volume occurring in conditions of brain atrophy
Hydrocephalus ex vacuo
A condition that classically occurs in overweight young females and is related to decreased CSF outflow of the arachnoid villi
Pseudotumor cerebri
The RAS-MAP kinase pathway is a signal tranduction pathway that leads to gene transcription. RAS is a G-protein that exists in active and inactive forms.
What makes RAS inactive?
What makes RAS active?
Inactive RAS: attached to GDP
Active RAS: bound to GTP (occurs after the tyrosine kinase receptor on the membrane autophosphorylates).
Note: Activated RAS starts a phosphorylation cascade tht starts with activation of RAS kinase. This results in activation of MAP (mitogen-activated protein) kinase, which enters the nucleus to influence gene transcription.
Annular pancreas is when the pancreas encircles the descending part of the duodenumand may lead to symptoms of duodenal obstruction in neonates. Embyologically, what causes annular pancreas?
The abnormal migration of the ventral pancreatic buds.
Ventral pancreatic bud gives rise to a portion of the head, the ucinate process adn the main pancreatic duct.
What is t(15:17) associated with?
*What type of cancer and what receptor is messed up?)
The M3 variant of Acute Myelogenous Leukemia, called Acute PROMYELOTCYTIC leukemia.
The gene for RETINOIC ACID RECEPTOR alpha from chromosome 17 is transferred to chromosome 15 in a location adjacent to the PML gene. The fusioni causes an abnormal retinoic acid receptor, inhibiting myeloblast differentiation.
Abnormal epidermal growth factor receptors are associated with what type of cancers?
ERB1: Non-small cell lung carcinoma
ERB2 (aka HER2/neu): breast cancer
Defective platelet derived grwoth factor receptor plays a role in what type of cancer?
CML: Chronic myelomonocytic leukemia
Abnormal Rb gene prediposes individuals to what two types of cancer?
Retinoblastoma and osteosarcoma
In the kidney, what does the ureteric bud ultimately give rise to?
The collecting system, including the collecting ducts, minor calyces, major calyces, the renal pelvis and ureters.
In the kidney, what does the metanephric mesoderm give rise to?
Glomerulus, Bowman’s space, the proximal tubule, loop of Henle, distal tubule and the collecting tubule.
What is associated renal angiomylipoma? (Benign tumor of blood vessels, smooth muscle and fat)
Tuberous sclerosis (autosomal dominant), so will present with brain harmartomas and ash-leaf skin patches. Patient can have seizures from the harmartomas.
What is the primary site of regulation of potassium concentrations in the tubular fluid and urine?
Collecting duct.
Note: 2/3 of filtered potassium is absorbed in the proximal convoluted tubule.
20% of that filtered potassium load will then occur in the loop of henle by the Na/K/2Cl transporter.
The rest occurs in the collecting duct and depends on state of kalemia in the body.
The left kidney lies immediately deep to the tip of the ______ rib.
12th
What cells would be expected to undergo hyperplasia and hypertrophy in the event of decreased kidney perfusion?
Modified smooth muscle cells of the afferent arteriole, which secrete renin from the juxtaglomerular apparatus. These cells are located in the afferent and efferent arterioles. In the event of low perfusion, the afferent JG cells will synthesize and secrete renin.
What essential protein is necessary to promote the growth and differention of T-cells?
Calcineurin, a protein phosphatase will work on NFAT (nuclear factor of activated T-cells), dephosphorylating it. Then, the NFAT will cuase IL-2 promotion.
IL-2 stimulates growth and differential of T-cells.
What do the immunosuppressant drugs, cyclosporine and tacrolimus, inhibit?
Calcineurin, which causes upregulation of IL-2 and therefore causes T-cell differentiation.
These drugs are commonly used as immunosuppressants in kidney transplantation.
Chronic NSAID use can cause what in the kidneys?
Chronic interstitial nephritis. Usually gets better when medication is stopped.
Amphotericin B works by binding ergosterol in fungal cell membranes to form holes. It is the drug of choice for mucormycosis. Considering the side effects of this med, what should be routinely monitored?
This drug is NOTORIOUS for renal toxicity.
Severe HYPOKALEMIA and HYPOMAGNESIA
*Note: May often relay daily supplementation.
A 64-year old male hospitalized with severe abdominal pain and hypotension begins to hyperventilate. Lab testing reveals metabolic acidosis, an increased anion gap and high plasma lactate levels. This patient’s findings are best explained by a low activity of what enzyme?
Pyruvate dehydrogenase.
Hypoxia induced lactic acidosis is typically caused by low activity of this enzyme because oxidative phosphorylation can’t take place and there is a high activity of lactase dehydrogenase.
When will you see someone with renal osteodystrophy?
End-stage renal disease: Causes hypocalemia via renal retention of phosphate and decreased renal synthesis of calcitriol (1,25-dihydroxycholecalceriferol vitamin D. Both hypocalcemia and the resultant secondary hyperPTH contribute to renal osteodystrophy.
A drug used to treat intraocular pressure is also a diuretic.
What is the drug and what part of the tubule does it work?
Acetazolamide: Carbonic anhydrase inhibitor.
It works in the proximal tubule.
Note; will cause alkaline urine because CA blocks NaHCO2 and water reabsorption in the proximal tubule. If CA is block, you pee out the NaHCO2. (alkaline urine)
Aldosterone antagonist commonly used in treating class III and IV heart failure patients. It is structually similar to steroids, so can cause gynecomastia, decreased libido and impotence.
Spironolactone.
NOTE: Eplerenone is a newer and more selective aldosterone antagonist that may produce less endocrine effects.
DNA-dependent RNA polymerase that incorporates short RNA primers into replicating DNA.
Primase
Topisomerases are enzymes that relieve the resultant strains from when helicase separates and unwinds, causing supercoiling.
Another name for topoisomerase.
Gyrase
During kidney transplantation, after connecting graft and host vessels, the kidney becomes cyanotic and mottled immediately. What type of hypersensitivity is this?
Type II - There are preformed recipient antibodies against antigens on the host organ.
Type I hypersensitivity (immediate) in cases of anaphylaxis, urticaria and some forms of seasonal allergies and asthma. What is happening on a cellular level in Type I?
Antigen leads to IgE class switching on B-lymphocytes.
Type of sensitivity reaction where antibody-antigen complexes along with complement bind and attract neurophils to cause increased inflammation and tissue damage at site?
Type III: Immune complex mediated.
Graft versus host disease is a type of what kind of hypersensitivity?
Type IV: Cell mediated, caused by competent donor T-cells form a donor attack host.
Anti-GBM ab can react with the type IV collagen in the glomerular basement membrane and alveoli (hematuria and hemoptysis) This is found in Goodpasture’s Disease. On light microscope, what will you see?
What about on IF?
Light microscope: Crescents (Rapidly progressive Glomerulonephritis, Type 1)
IF: linear deposits of IgG and C3 along the glmoerular basement membrane.
What is the first way to tell if diabetes is injury the kidneys?
Microalbuminuria
HIV patient has visual problems.
What is probably causing it?
What drug do you give/
CMV-causes retinitis in AIDS patients.
Foscarnet-an analog of pyrophophate that can chelate calcium and promote nephrotoxic renal magnesium wasting. These toxicities can result in symptomatic hypocalcemia and hypomagnesemia.
What happens to the GFR and FF (filtration fraction) when you have severe vasoconstriction of the EFFERENT arteriole?
GFR: Increases (to a certain extent)
FF: Always increases.
Spike and dome appearance on electron microscopy?
Membranous glomerulopathy: most common cause of nephrotic syndrome in adults.
It can be secondary to underlying malignant tumors, infections and certain mediations. Diffuse thickening of the glomerular basement membrane (on light microscopy) without increased cellularly.
Remember, has “membranous” in the name, so is Ig mediated.
Caucasian male undergoing treatment with Amphotericin B for disseminated histoplasmosis complains of weakness and palpitations. ECG reveals frequent premature ventricular beats. What does drug toxicity of this drug cause?
Renal tubular dysfunction. So, hypokalemia and hypomagnesia cause the problem in the heart.
What does ureteral constriction or obstruciton do to the GRF and FF?
Decreases both.
Why do uric acid crystals tend to precipitate out in the collecting ducts or DCT?
This is more acidic. They will be soluble in a normal pH. They need a more acidic environment to precipitate out.
Wegener’s Granulomatosis
c-ANCA
Upper respiratory (sinus infection) Pulmonary systems (hemoptysis) Renal: hematuria (Rapidly progressing glomerulonephritis-crescentric)
Renal Blood Flow (RBF) refers tot the volume of blood that flows through the kidney per unit time and can be calculated by dividing the
RPF/(1-hematocrit)
How do you determine renal plasma flow (RPF)
RPF = PAH clearance
PAH clearance is determined by:
(urine [PAH] X urine flow rate)/plasma [PAH]
Coca-cola colored urine and facial edema after a step infection is poststreptococcal glomerulonephritis. What characteristic is most likely to affect prognosis of these patients.
Age: children recover 95% of the time.
Adults: only 60% will resolve completely.
Where will you find the most concentrated urine in the absence of ADH?
The junction between the descending and ascending limbs of the loop of Henle.
A patient presents with periorbital edema, hematuria, and a has a history of impetigo (or cellulitis or pharyngitis). What is mediating the damage to the patient’s kidneys?
Immune complexes (type III hypersensitivity). Causing poststreptococcal glomerulonephritis.
More than 60% of fluid filtered into the glomerulus is reabsorbed in the ______________, regardless of the patient’s hydration status.
Proximal tubule.
What effect does aldosterone have on the following:
Na+
N+
K+
H2O
Na+: reabsorbed
H+: secretion (follows K+)
K+: secretion
H2O: reabsorption
Alcoholic (homeless) man is brought in to the ER with vomiting and prolonged oliguria. Renal biopsy shows multiple oxylate crystals observed in the tubule lumen. What happened?
Ethylene glycol is rapidly absorbed in the GI tract and metabolized to glycolic acid, which is toxic to renal tubules, and to oxalic acid, which precipitates as calcium oxylate crystals in the renal tubules.
High anion gap and metabolic acidosis and osmolar gap are typical.
What is the normal kidney filtration fraction in a normal healthy individual?
20%
A 45-year old female with polyuria receives a vasopressin injection. Her urinary output decreases signficantly shortly afterward. Renal clearance of which of the following substances would be most significantly reduced from baseline after the injection?
Glucose Creatinine Urea Para-amino hippuric acid Calcium
Urea
Vasopressin (ADH) produces a V2 receptor-mediated increase in permeability to water and urea at the luminal membrane of the inner medullary collecting duct. The increase in urea reabsorption corresponds to a decrease in the fractional excretion of urea and a decrease in renal clearance of urea from plasma.
Which type of diuretic (loop or thiazide) are more likely to cause hypercalcemia?
Thiazide (which work in the distal convulated tubule)
They work by blocking Na-Cl symporters. Since only a small amount of Na+ reaches the distal tubules, thiazides are not as efficacious as loop diuretics.
Kimmelstiel-Wilson nodules in the kidneys indicate nodular glomerulosclerosis. What are K-@ nodules pathognomonic for?
Diabetes nephropathy
Note: ACE inhibitors and ARBs can prevent progression to diabetic nephropathy!!!
What happens to most people who experience acute tubular necrosis?
They experience tubular re-epithelization and regain renal function.
42-year-old white guy with hypertension and hematuria undergoes renal biopsy. Light microscopy reveals cellular proliferation, focal necrosis, and crescent formation of most glomeruli. On IF, THERE ARE NO IG COMPLEMENT DEPOSITS. What additional findings would you expect?
Serum anti-neurophil cytoplasmic bodies
(c-ANCA Wegeners)
p-ANCA-Churg Strauss
Note: There are not Igs to bind complement, so nothing on IF.
What kind of drug is furosemide?
Loop diuretic: inhibits Na-K-2Cl symporter in the ascending loop of henle.
What would be the common findings of the following in chronic renal failure?
- PTH
- Calcium
- Phosphate
- Calcitriol (vitamin D)
- PTH: high
- Calcium: low
- Phosphate: high
- Calcitriol: low