USLME world 1 Flashcards
Collagen synthesis
RER: -Rough ribo: synthesizes Pre-Po-Alpha-chains -Signal Sequence cleaved: pro-alpha-chains -Hydroxylation: Proline & Lysine VITAMIN C DEPEnDENT -Glycosylation: of Galactose and Glucose -Assembly of pro-alpha chains into procollagen TRIPLE HELIX (transfered to Golgi and secreted) EXTRACELLULAR: -N and C terminals cleaved by peptidases: Tropcollagen -Spontaneous assembly: collagen fibrils -Covalent cross links made by Lysyl oxidase
Inulin PAH
Inulin=GFR, filtered PAH=filtered + secreted, renal plasma flow (better than creatinine for measuring bc creatinine not secreted as much)
Odds ration
ad/bc odds that the group with the disease was exposed to the risk factor (a/c) divided by the odds that the group without the disease was exposed (d/b) disease risk factor + - + a b - c d
Beck’s triad: -Jugular venous distension -hypotension -tachycardia -distant/muffled heart sounds -pulsus paradoxus
Cardiac tamponade -Elevated central venous pressure in superior vena cava–> JVD -low QRS and electrical alternans. -lung sounds nrml
Pleuritic chest pain + pericardial friction rub
Acute fibrinous pericarditis follows URI
Pulsus paradoxus
decreased amplitude of systolic blood pressure by > 10mmHg during inspiration. (Cardiac tamponade, astham, obstructive sleep apnea, pericarditis, croup)
6th aortic arch
pulmonary arteries & ductus arteriosus
1st aortic arch
maxillary artery
2nd aortic arch
stapedial artery and hyoid artery
3rd aortic arch
common carotid artery and proximal part of internal carotid artery
4th aortic arch
Left: aortic arch Right: proximal part of right subclavian artery
metalloproteinases
Zinc containing enzymes that degrade extracellular matrix (collagen, laminin, fibronectin). Metalloproteinases are essential for proper tissue remodeling during wound healing
FOscarnet
viral DNA polymerase inhibitor that binds pyrophosphate-binding site of the enzyme. DOES not require viral kinase activation. use: CMV retinitis if ganciclovir fails or in acyclovir-resistant HSV SE” Nephrotox Resistance: mutated DNA polymerase
Acute goutry arthritis tx, drug’s moa
NSAIDS-first line 2nd line: Colchicine: prevent MT formation by binding tubulin SE: diarrhea, nausea, vomiting, abdominal pain bc also disrupts MT in GI mucosa cells
drugs that act on MT
Mebendazole ( anti-helminthic) Griseofulvin (anti-fungal) Colchicine (anti-gout) Vincristine/Vinblastine (anti-cancer) Paclitaxel (anti-cancer)
Gingival hyperplasia SE drugs
Phenytoin, verapamil, cyclosporine, nifedipine
SLE like syndrome SE drugs
SHIPPE: Sulfa, Hydralazine (Vasodilation arteries>veins, increase cGMP-> smooth muscle relaxation. use: CHF, HTN in pregnancy) , INH, Procainamide (Class IA), Phenytoin, Etanercept (TNF receptor fusion protein)
Alveolar-arterial gradient (A-a)
Palveoli (O2)-Parterial (O2)=10-15mmHg=nrml If nrml-> no V/Q mismatch, no diffusino impairment If nrml and patient hypoxemic: alveolar hypoventilation or inspriing low P(O2)
4 major causes of hypoxemia
alveolar hypoventilation, ventilation perfusion mismatch,diffusion impairment, right-left shunting. The first one has nrml (A-a) gradient
Rifampin
Inhibits DNA dependent RNA polymerase Use: TB (NOT ALONE), with dapsone for leprosy to delay resistance, PROPHYLAXIS for meningococcal and chemoprophylaxis for H.influenza type B. Tox: Minor hepatotox, orange body fluids, Ramps UP CYP 450 (But Rifabutin doesnt!)
Young Caucasian, Recurrent Sinusitis
Cystic fibrosis: -Auto recessive, chrm.7-CFTR gene defect: deletion of Phe508 CFTR: ATP-gated Cl channel secrete Cl in lungs & GI and reabsord Cl in sweat glands (sweat test). Mutation: misfolded, stays in RER. Increased intracellular CL leads to Increased Na reabsorption via epithelial Na channel therefore to H2O reabsorption-> abnml think mucus in lungs and GI. Increased Na reabsorption also means negative transepithelial potentia difference
Lecithin/Spingomyelin <1.5
Neonatal Distress Syndrome if below 2 by 35 gestational weeks Surfactant starts being secreted in 3rd trimester by penumocytes II Lecithin: phosphatidylcholine
Hemoptysis, hematuria, Histo: focal necrosis of alvelolar wall and intra-alveolar hemorrhage, Kidney nep
Goodpasture HLA DR2 associated Type II hypersensitivity reaction, antibodies to GBM and alveolar basement membrane, linear IF, glomerulonephritis with crescent of fibrin and plasma proteins, macrophages…
Subcutaneous nodules on knee, dorsum of hand, achilles tendon xanthomas. Elevated total cholesterol, elevated LDL cholesterol.
Familiarl hypercholesterolemia: auto dominant Defective or absent LDL receptors. Excessive LDL deposits in arteries as atheromas and in tendons and skin as xanthomas xanthomas=hyper TG and cholesterol
Mitral Stenosis
Late Diastolic murmur follows opening snap. If interval between S2 and OS decreases=worst!!!! Always Rheumatic Fever Leads to LA dilation Expiration: increases LA return: enhances MS
Rheumatic Fever
Group A Strep. Pyogenes, Beta-hemolytic, Coagulase positive, Catalase negative, Bacitracin sensitive (Causes : Pharyngitis,Cellulitis, Erysipelas, Rheumatic Fever, Post-strep GMN) Death cause: myocarditis Early lesion: mitral valve regurgitation (systolic holosystolic, high pitched, apex->axilla) BUT late lesion is mitral stenosis ASCHOFF BODIES: granuloma with giant cells & ANITSCHKOW cells: enlarged Mo. w/ ovoid, wavy, rod-like nucleus TYPE II hypersensitivity: Antibodies to M protein cross react with self antigens! FEVERS: Fever, Erythema marginatum, Valve damage, ESR increase, Red hot joints, Suubcutaneous nodules, Sydenham chorea!
Peutz Jeghers Syndrome
Auto DOMINANT, multiple nonmalignant hamartomas in GI tract + hyperpigmentation of mouth, lip, hands, genitalia. (can get intussusception, obstruction of GI)
Increase risk of CRC and other maligancies.
Mutation in Serine/Threonine kinase 11
mutliple cafe au lait macules, cutaneous neurfibromas, axillary or inguinal freckling, optic glioma, iris hamartomas, osseus lesions
NF1
Lipoma vs Liposarcoma
Lipoma: Soft, rubbery, mobile, subcutaneous nodules made of mature fat cells without pleomorphism.
Liposarcoma: Soft-tissue malignancies, many lipoblasts (cells that make non mb bound cytoplasmic lipid), nuclear indentations, scallopingof nuclear mb. Middle-aged, slow growing, painless of trunk or lower extremities (picture)
Fibrosarcoma
Fibroblast based malignancy, anaplastic spindle cells, marked disarray, pleomorphism, mitotic activity, hemorrhage, necrosis. Secondary to Piaget Bone disease.
Pemphigus Vulgaris vs Bullous vs dermatitis herpetiformis
Pemphigus: IgG autoAb to desmogleins 1 and 3 (spinous stratum), IF: netlike pattern (reticular)
Bullous: autoAb to hemidesmosomes (attached to basmt mb), bellow epidermis. IF linear
Dermatitis herpetiformis: IgA depostio in upper papillary dermis
Epidermolysis bullosa acquisita: autoAb to type VII collagen
Horner syndrome
PAM is horny
Ptosis
Anhidrosis
Miosis
AM-hemifacial!
Hypothalamus -> spinal cord (down)-> (& back up) superior cervical ganglion-> eye, sweat glands of face
45XO
Turner Syndrome:
Short stature, shield chest, Primary amenorrhea, no barr body,complete monosomy XO or mosaicism
DECREASED estrogen w/ INCREASED LH&FSH
Ovarian streak (ovarian dysgenesis): infertile but have uterus and with IVF and estrogen and progesterone supplementation can get pregnant. Nrml uterus + vagina.
Bicuspid aortic valve, preductal coarctation of aorta. Horseshoe kidney, lymphatic defects (webbed neck or cystic hygroma, lymphedema of feet and hands)
Bromocriptine
Dopamine receptor agonist can inhibit prolactin and restore fertility in women with hyperprolactenemia
Or used for pituitary adenoma (prolactinoma)
or PARKINSON tx
Clomiphene citrate
blocks negative feedback of circulating estrogen at hypothalamus, increases FSH and LH
Use: PCOS, SERM, to treat infertility due to anovulation
drugs that cause Diabetes insipidus
lithium (used for mood stabilization in bipolar disoder, can also be used in SIADH) and
dimeclocycline (ADH antagonist_tetracycline family used in SIADH)
2yo, painless red bleeding per rectum with discharge that has gastric mucosal cells
Meckel diverticulum
Prokaryotic DNA polymerase I vs III
I: Removes RNA primers in lagging strand and replaces it with DNA
III: makes DNA in 5’ to 3’ direction
CA 125
alpha fetoprotein
CA 19-9
Ovarian cancer
Hepatocellular cancer, nonseminomaotus germ cell tumor (endodermal sinus yolk sac tumors)
adenocarcinoma of pancreas
Alkaptonuria
Inherites deficiency of homogentisate 1,2-dioxygenase in degradation of tyrosine to fumarate
auto recessive
Dark urine on standing/exposure to air
Destructuve arthritis later in lige bc homogentisic acid deposits in articular cartilage
Ochronosis, blue-grey discoloration of skin and ears too, brown in sclera.
Renin stimulation
Decreased NaCL
Decreased pressure in afferent arteriole
Sympathetic stimulation
EKG signs of hyperkalemia
HypoCalcemia
HyperCalcemia
Hypokalemia
Peaked T waves, loss of P wave, prolonged PR intercal, widening of QRS compkex, slowed HR–>venti fibrillation
Hypocalcemia: QT prolongation
HyperCa: QRS shortening
Hypokalemia: QT interval prolongation, U waves and ST depression
Parinaud syndrome
Paralysis of conjugate vertical gaze due to lesion in superior collliculi (pinealoma-> mass effect)
Upward gaze palsy, absent pupillary light reflex, failure of convergence and wide based gait.
Damage to oculomotor, trichlear and edinger westphal nucleus (parasympathetic innervation of eye)
Phenylepherine
alpha 1 adrenergic receptor agonist
Arterial vasoconstriction: increased in vascular resistance and BP–> increase in BP elicits baroreceptor-mediated vagal tone which leads to decreased stroke volume and slowed HR
(phenylephrine increase TPR so body decreases CO to maintain BP by decreasing HR and SV
BP=TPR*CO and CO=HR*SV)
Pulse-pressure is decreased bc of the reflex (decreased SV and increased afterload)
CAAT and TATA box
80-70bp upstream and 25bp upstreamof transcription start site ATP
Promote initiation=bdg site for RNA polymerase II=transcription initiator