Block 5 Flashcards
What type of bone does osteoporosis primarily involve? What findings will you see?
Primarily involves trabechular (spongy/cancellous) bone
You will see trabechular thinning with fewer interconnections
What disease presents with thymus abnormalities, such as thymoma, thymic hyperplasia and extraocular muscle weakness?
Myasthenia gravis
What is confounding?
When a perceived association between an exposure and an outcome is actually explained by a confounding variable associated with both the exposure and the outcome
(example: kids and shoe size, IQ, confounding = age)
What method is generally used in the design stage of case-control studies to control confounding?
Matching
What do you see after 12-48 hours of inadequate blood flow to the brain?
“red neurons”
eosinophilic cytoplasm, puknotic nuclei, loss of Nissl substance
What do you see after 24-72 hours of inadequate blood flow to the brain?
necrosis and neutrophilic infiltration
What do you see after 3-5 days of inadequate blood flow to the brain?
macrophage infiltration and phagocytosis
What do you see after 1-2 weeks of inadequate blood flow to the brain?
reactive gliosis, vascular proliferation –> liquefactive necrosis
What do you see after >2 weeks of inadequate blood flow to the brain?
glial scar –> cystic area surrounded by gliosis (>1 month)
Do NK cells express CD4, CD8, or CD3 molecules on their surface?
No
Do NK cells express either CD16 or CD56?
Yes
Do NK cells require the thymus for maturation?
No, they are present in athymic patients
Do NK cells have antigen-specific activities or require exposure to antigen for activation? Do they possess antigen meory ability?
NO to all of those things
Are NK cells activated by interferon-gamma and IL-12?
Yes
What nutritional changes related to the pancreas may occur in severe CF?
Severe CF may cause total obstructino of pancreas followed by complete fibrotic atrophy of exocrine glands –> deficiency in fat soluble vitamins
What vitamin is a nueroprotective agent that may slow functional losses in Alzheimer’s?
Vitamin E (a-tocopherol)
What may avitaminosis A contribute to?
Squamous metaplasia of the epithelial lining of pancreatic exocrine ducts, which are already injured and predisposed to squamous metaplasia by inspissated mucus (thickened)
normal levels of what vitamin are required to maintain orderly differentiation of specialized epithelia, including mucus-secreting columnar epithelium?
vitamin A
when a deficiency state exists, the epithelium undergoes squamous metaplasia to a keratinizing epithelium
which bacteria can destroy RBCs through cold-aggultinins, leading to mild anemia and also cause Stevens-Johnson syndrome & joint pains?
mycoplasma pneumonia
What happens to patients with galactosemia and galactitol accumulation?
galactitol accumulates in the lens of patients and causes osmotic damage leading to cataract formation
How is galacticol formed?
from excess circulating galactose in galactosemia by aldose reductase
Where does the PCL attach?
Inferior to the posterior part of the intercondular area of the tibia and the anterior part of the lateral surface of the media epicondyle of the femur
What a Kerley B lines and when are they seen?
They are seen on the xrays of pts with left heart failure
Short horizontal lines situated perpendicularly to the pleural surface that represent edema of the interlobular septa
In A fib, what regulates the number of atrial impulses that reach the ventricle and determines the ventricular contraction rate?
AV node
How does glucose influence the lac operon?
increased glucose results in decreased expression of the lac operon
How is the lac operon positively regulated?
It’s positively regulated by the binding of catabolite activator protein (CAP) to a site slightly upstream from promoter regions
This only occurs when cAMP concentrations are high
Glucose decreases activity of adenylyl cyclase –> decreased cAMP, regpressing lac operon
What causes increased lung elastic recoil leading to airway thickening due to increased outward pulling (radial traction) by the surrounding fibrotic tissue?
interstitial lung diseases, which cause progressive pulmonary fibrosis with thickening and stiffening of the pulmonary interstitium
What bacteria is a blood-loving organism that requires both X factor (hematin) and V factor (NAD+) to grow?
H. influenzae
What adrenal enzyme deficiency impairs the synthesis of androgens, estrogens, and cortisol but does NOT inhibit mineralocorticoid production?
17a-hydroxylase deficiency
What do boys with 17a-hydroxylase deficiency present with?
Boys appear phenotypically female at birth but lack internal female genetalia due to the absence of virilizing androgens in utero
What do females with 17a-hydroxylase deficiency present with?
Females develop normal internal and external genetalia
What electrolyte abnormalities may be seen around puberty with 17a-hydroxylase deficiency?
Excessive production of mineralcorticoids by adrenals results in hypertension, hypokalemia, and low renin levels
What is the immediate treatment for someone poisoned with rodenticides?
Rodenticides contain brodifacoum, a long acting 4-hydroxycoumarin derivative
Immediately treat with fresh frozen plasma and vitamin K to prevent coagulopathy and abnormal bleeding
What factors does FFP replenish? What factors does cryoprecipitate replenish?
FFP = factors 2, 7, 9, 10
cyroprecipitate = factors 8, 13, vWF, and fibrinogen
What are the sizes of petechiae, purpurae, and ecchymoses?
Petechiae = less than 5 mm
Purpurae = 5 mm - 1 cm
ecchymoses = >1 cm
What does IGF-1 mediate and where/how is it produced?
IGF-1 mediates growth-promoting effects from GH
released from the liver following a stimulation of hepatic GH receptors and subsequent activation of the JAK-STAT signaling pathway
IGF-1 binds to a specific receptor tyrosine kinase found on cells throughout body to stimulate growth
What is the most abundant amino acid in collagen?
glycine
triple helix = (-Gly-X-Y)333
What drugs, administered with statins, will cause increased incidence of myopathy and rhabdomyolsysis leading to acute renal failure?
statins are metabolized by cytochrome P-450 3A4 (with exception of pravastatin)
administratino of 3A4 inhibitors (macrolides) will increase SE’s
What should HIV patients with CD4+ counts <50 cells/uL be administered to prevent MAC (mycobacterium avium complex) infection?
prophylactic azithromycin
What is mycobacterium avium complex?
MAC is a common opportunistic pathogen that causes disseminated disease in HIV+ patients
presents with pallor, hepatosplenomegaly, clear chest X-ray, elevated alk phos and lactate dehydrogenase
culture grows optimally at 41 degrees C (to differentiate from M. tuberculosis)
What cardiac defects are associated with DiGeorge syndrome?
Tetralogy of Fallot
interrupted aortic arch
This 22q11.2 deletion causes thymic aplasia, failure of parathyroid formation due to defective development of 3rd and 4th pouch
DiGeorge Syndrome
What lab abnormality and infection history do pts with DiGeorge syndrome present with?
hypocalcemia tetany (no PTH)
recurrant viral and fungal infections (no T-cells)
What lab abnormality is caused by administration of ACE inhibitors with K+ sparing diuretics?
profound hyperkalemia
Amiloride, triamterene, and spironolactone are all…
K+ sparing diuretics
vaginal agenesis aka Mullerian aplasia
no upper vagina (short vagina) and variable uterine development
XX females with normal ovaries and therefore secondary sexual characteristics
androgen insensitivity syndrome
pts are 46,XY males who appear phenotypically female due to an androgen receptor defect
pts have minimal axillary or pubic hair due to androgen resistance
pts have cryptorchid testes (absent from scrotum) and no uterus or ovaries
Kallman syndrome
occurs due to decreased synthesis of GnRH in the hypothalamus
although females are rarely affected, those with the condition present with primary amenorrhea, no secondary sex characteristics, and an olfactory sensory defect
Klinefelter syndrome
47,XXY
affects males and is characterized by tall stature, poorly developed secondary sex characteristics, atrophic testes, and infertility
Turner syndrome
45,X
a common cause of primary amenorrhea
affect individuals have short stature, webbed neck, shielded chest, and “streaked” or fibrotic ovaries
usually don’t develop secondary sex characteristics
HIV patient with abdominal distention and anorexia, ascites and a large mass surrounding the small intestine
biospy reaveals uniform, round, medium-sized tumor cells with basophillic cytoplasm and a proliferation fraction (Ki-67 fraction) of >99%
Burkitt lymphoma
balanced t(8;14) translocation, which causes over expression of c-MYC, a transcriptional regulator that controls cell proliferation
Burkitt lymphoma
What effect do chronic EBV and increased B-cell proliferation have on c-MYC translocations?
increased risk of c-MYC translocations
what symptoms cannot be corrected in severe thiamine deficiency?
memory and learning abnormalities usually persist as Korsakoff syndrome: damage to the anterior and dorsomedial thalamic nuclei
the power of a study is…
the probability of seeing a difference when there is one
Power = 1-beta, where beta is the Type II error rate
Characterized by the abnormal proliferation of mast cells and increased histamine secretion
Histamine increases production of gastric acid by parietal cells
syncope, flushing, hypotension, tachycardia, bronchospasm, pruritis, urticaria, dermatographism (skin writing)
systemic mastocytosis
