Uworld_notes-2.pdf

QId: 540 Immunology

- Allergy & Immunology

Activation of complement by IgM prior to antigen binding is prevented because of the hidden C1 binding site. Once IgM binds to the antigen, conformational change -- > exposure of the C1 binding site.

QId: 8539 Immunology

- Allergy & Immunology

C3a, C4a, C5a - anaphylotoxins C5a - recruits and activates neutrophils, monocytes, eosinophils and basophils. C3a - only eosinophils and basophils

QId: 10570 Biostatistics Epidemiology

- Biostatistics &

Nested case-control studies start as cohort studies which are studied over time to check for any development of disease. Participants who develop an outcome of interest become cases for a case-control study. Qualitative study uses focus groups, interviews adn other anthropologic techniques to obtain information for explaining quantitative results. Systemic reviews and meta-analyses combine teh results fo several published studies to estimate the pooled effect.

QId: 154 Pharmacology

- Cardiovascular System

Ca channel blockers -- > precapillary arteriolar dilation -- > edema. ACE inhibitors and ARBs cause postcapillary venodilation -- > normalize pressure when used with Ca channel blockers -- > decreased edema.

QId: 2023 Anatomy

- Cardiovascular System

3 main groups of venous circulation in embryo: Umbilical - degenerates Vitelline - forms portal circulation Cardinal - systemic venous circulation

QId: 475 Pathology

- Cardiovascular System

Adenocarcinomas produce a thromboplastin-like substance capable of causing chronic intravascular coagulations that can disseminate and tend to migrate.

QId: 711 Pharmacology

- Cardiovascular System

Statins - proven to show mortality benefits in coronary events. Along with inhibition of cholesterol synthesis, it has anti-inflammatory properties, improve endothelial dysfunction and appear to stabilize atherosclerotic plaques.

QId: 161 Pharmacology

- Cardiovascular System

Pravastatin, unlike other statins, is not metabolized by the liver through P-450 3A4

QId: 181 Pathology

- Cardiovascular System

Cardiac changes due to aging - sigmoid interventricular septum (bowing of the lower part), decrease in LV chamber size (apex-to-base shortening), calcified aortic valve.

QId: 2105 Pathophysiology System

- Cardiovascular

AR due to aortic root dilation (Marfans') - best hear at the right upper sternal border. AR due to valvular pathology (eg: bicuspid valve, RHD) - best heard at left third intercostal space.

QId: 713 Pharmacology

- Cardiovascular System

Low-dose aspirin -- > non-specific inhibition of COX-1 and 2. Side effects mainly due to inhibition of COX-1. Used as anti-platelet-aggregation (TXA2) -- > increased risk of bleeding by itself. Inhibition of COX-1 -- > impaired synthesis of prostaglandins E2 and I2 -- > gastiric hyperacidity -- > impaired mucosal defense -- > mucosal injury and bleeding. GI bleeding can be a serious side effect. PPIs can be used along with aspirin to prevent the side effect. Very high doses can cause hyperpnea (direct stimulation of respiratory center in medulla) and vertigo (ototoxicity).

QId: 900 Pharmacology

- Cardiovascular System

Ischemic tissues - higher than normal resting membrane potential -- > delayed voltage-dependent recovery of sodium channels from the inactivated to the resting state -> increased binding of class IB agents.

QId: 14780 Pharmacology System

- Cardiovascular

RCA - SA node, AV node, most of Bundle of His and proximal part of right bundle branch LCA - Bundle of His, left bundle branch, remaining part of right bundle branch

QId: 15196 Pathology

- Cardiovascular System

Ischemic heart disease/obstructive coronary disease -- > dilated cardiomyopathy because of volume overload from decreased contractility

QId: 33 Pathophysiology System

- Cardiovascular

Bicuspid valve - early onset aortic stenosis around 50 years of age in > 50% patients (10 years earlier then normal). It is due to increased hemodynamic stress, accelerating the normal aging process.

QId: 85 Pathophysiology System

- Cardiovascular

Increased afterload decreases murmur in AS and HCM. In AS, pressure gradient across aortic valve decreases -- > decreased murmur.

QId: 43 Pathology

- Cardiovascular System

Myocardial hibernation - chronic ischemia -- > metabolism and cardiac function reduced to match the decreased coronary blood flow -- > new equilibrium preventing necrosis; dereased expression and disorganization of contractile and cytoskeletal proteins, altered adrenergic control and reduced calcium responsiveness -- > decreased contractility and LV systolic dysfunction. Revascularization -- > restoration of blood flow -- > improved cardiac function. Ischemic preconditioning - brief repetitive episodes of myocardial ischemia with intermittent reperfusion -- > protection of myocardium from prolonged episodes of ischemia. Repetitive episodes of angina prior to MI can delay cell death after complete coronary occlusion and therefore provide greater time for myocardial salvage with coronary revascularization.

QId: 13600 Genetics

- Cardiovascular System

Arrhythmogenic right ventricular cardiomyopathy - fibrosis and scarring of RV -- > ventricular arrhythmias and SCD. Cause - impaired desmosome function due to mutations in genes encoding desmosomal proteins (eg: desmoplakin, plakoglobin).

QId: 7640 Pharmacology System

- Cardiovascular

Torsades de pointes can be differentiated from other polymorphic tachycardia because it is always associated with prolonged QT interval.

QId: 2075 Pathology

- Cardiovascular System

Infective endocarditis pathogenesis - disruption of normal endocardial surface -- > focal adherence of fibrin and platelets (usually at the areas of maximal turbulence to blood flow like atrial surface of incompetent AV valves) -- > sterile fibrin-platelet nidus -- > colonization of nidus due to bacteremia -- > microbial growth -- > further activation of coagulation system. Macroscopic vegetations contain fibrin and platelets on the surface with RBC debris, WBCs and clusters of microorganisms embedded deep within the lesion.

QId: 244 Pathophysiology System

- Cardiovascular

Severe AS -- > LVH -- > stiff ventricle -- > ventricular filling depends on atrial contraction. In the setting of atrial fibrillation, atrial kick lost -- > decreased preload -- > exaggeration of the reduced cardiac output. Fluid also backs up into pulmonary veins -- > pulmonary edema. Therefore, in patients with severe AS who present with atrial fibrillation, cardioversion is indicated.

QId: 1516 Physiology

- Cardiovascular System

NO and adenosine are important for maintaining the coronary blood flow in the autoregulatory range of blood pressures.

QId: 293 Pathophysiology System

- Cardiovascular

Reperfusion injury due to: Free radicals generated from parenchymal cells, endothelial cells and leukocytes. Irreversible mitochondrial dammage (mitochondrial permeability transition) Inflammation, which attracts circulating neutrophils Complement pathway activation

QId: 464 Pathology

- Cardiovascular System

Hypertension -- > medial hypertrophy of aortic vasa vasorum -- > reduced blood flow to the aortic media -- > medial degeneration with a loss of smooth muscle cells --> aortic enlargement and increased wall stiffness -- > increased aortic wall stress -- > intimal tearing -- > dissection.

QId: 14964 Pathology

- Cardiovascular System

Aortic stenosis - endothelial damage -- > fibroblast proliferation and release of osteopontin from macrophages -- > differentiation of fibroblasts into osteoblast-like cells -- > aberrant bone matrix deposition -- > progressive valvular calcification and stenosis

QId: 467 Pathology

- Dermatology

A bluish neoplasm underneath the nail bed can be a glomus tumor or a subungual melanoma.

QId: 1214 Pharmacology

- Dermatology

Topical steroids -- > anti-inflammatory actions and also decrease in production of ECM collagen and GAGs -- > atrophy of dermis, drying, cracking and/or tightening of skin

QId: 15431 Microbiology

- Dermatology

Cat and dog hookworms (Ancylostoma braziliense, A. caninum) - cannot penetrate the basement membrane -- > don't mature into adults in humans (incidental hosts).

QId: 1108 Pathology

- Dermatology

Plane xanthomas - PBC Xanthomas - foamy macrophages; enclosed by inflammatory cells and fibrotic stroma Xanthelasma - foam cells without any inflammation/fibrosis.

QId: 1110 Pathology

- Dermatology

Vitiligo - autoimmune activity, neurohumoral toxicity, self-destruction via toxic intermediates during melanin synthesis.

QId: 15379 Pathophysiology

- Dermatology

Bacterial metabolism of apocrine secretions -- > body odor due to sweat. Bromhidrosis - excessive and offensive body odor.

QId: 7585 Pharmacology

- Dermatology

Pathophysiology of acne: Follicularepidermalhyperproliferation Excessive sebum production Inflammation Propionibacterium acnes Dihydrotestosterone -- > follicular epidermal proliferation and excessive sebum production Lithium and EGFR inhibitors also cause acne.

QId: 7649 Pathology

- Dermatology

Seborrheic keratoses in malignancy -- > tumor production of cytokines or growth factors (IGF-1, FGF). Acanthosis nigricans in malignancy - similar mechanism.

QId: 936 Pathology

- Dermatology

Acanthosis nigricans - benign and malignant Benign - insulin resistance (insulin and IGF stimulate epidermal and dermal proliferation). Malignant - due to underlying malignancy (usually gastric adenocarcinoma).

QId: 1114 Pathology

- Dermatology

Urticaria - superficial dermal edema Angioedema - deep dermis and subcutaneous tissue edema

QId: 1244 Biochemistry

- Dermatology

Collagen - tensile strength Elastin - elasticity Glycosaminoglycans - compressibility

QId: 8904 Pathophysiology

- Dermatology

Ephelides (freckles) are due to increased melanin production in melanocytes. Solar lentigines are due to increased melanocytes.

QId: 15695 Pathology

- Dermatology

Erythema multiforme - circulating pathogens phagocytosed by peripheral mononuclear cells and are brought to the epidermis where DNA fragments are transferred to keratinocytes via direct cell-to-cell spread (upregulation of adhesion molecules). Pathogen-specific cytotoxic T-cells then recognize foreign antigens produced by keratinocytes and initiate an inflammatory cascade that results in epithelial damage.

QId: 13911 Microbiology

- Dermatology

HIV patients/immunocompromised patients are unable to contain scabies infection due to impaired cell-mediated immunity -- > crusted scabies.

QId: 1633 Anatomy

- Ear, Nose & Throat (ENT)

Noise-induced hearing loss is due to trauma to the stereociliated hair cells of the organ of Corti.

QId: 582 Pathophysiology Metabolism

- Endocrine, Diabetes &

Cryptorchidism - seminiferous tubules are damages; Leydig cells are preserved -- > increased FSH and normal LH.

QId: 8531 Pathology Metabolism

- Endocrine, Diabetes &

Preproinsulin loses singal peptide -- > proinsulin which is packaged in the golgi -- > cleaved into insulin and C-peptide in secretory granules.

QId: 15770 Pharmacology Metabolism

- Endocrine, Diabetes &

SGLT-2 inhibitors -- > decreased sodium resorption -- > increase phosphate absorption in distal tubule -- > PTH secretion -- > decreased bone density.

QId: 920 Pharmacology Metabolism

- Endocrine, Diabetes &

Adiponectin - secreted by fat tissue that increases the number of insulin-responsive adipocytes and stimulates fatty acid oxidation.

QId: 954 Physiology Metabolism

- Endocrine, Diabetes &

5a reductase = 2 types. Type 1 present in postpubescent skin, type 2 in genitals.

QId: 11917 Biochemistry Metabolism

- Endocrine, Diabetes &

Fasting -- > stress hormones (catecholamines, ACTH and glucagon) act on Gs receptor of adipocytes -- > activation of hormone sensitive lipase -- > TAGs broken down into glycerol and FFA -- > glycerol enters gluconeogenesis pathway and FFAs are broken down into ketone bodies. LPL has similar function, but it is involved in transporting FFAs into adipocytes storage and used by tissues for energy production (not maintenance during starvation).

QId: 1887 Biochemistry Metabolism

- Endocrine, Diabetes &

Liver can synthesize ketone bodies but cannot utilize them because it lacks an enzyme (succinyl CoA acetoacetate CoA transferase/thiophorase) which is required to convert acetoacetate to acetoacetyl CoA.

QId: 1012 Pathology Metabolism

- Endocrine, Diabetes &

Islet amyloid polypeptide is a protein secreted by pancreatic ß cells. It is low in Type 1 DM due to destruction of islet cells.

QId: 1066 Biochemistry Metabolism

- Endocrine, Diabetes &

Amino acids undergo transamination transferring their amine nitrogen to glutamate (predominantly) which is then deaminated to produce ammonia -- > converted to urea via urea cycle

QId: 1073 Biochemistry Metabolism

- Endocrine, Diabetes &

Glucose polymer = starch; starch has an unbranched portion = amylose and branched portion = amylopectin.

QId: 989 Biochemistry Metabolism

- Endocrine, Diabetes &

Intracellular cortisol receptors are bound to the heat shock proteins in the inactivated state.

QId: 1383 Biochemistry Metabolism

- Endocrine, Diabetes &

G protein-coupled receptors - 3 domains. Extracellular domain - ligand binding Transmembrane domain - anchoring the cell membrane Intracellular domain - heterotrimeric G proteins Extracellular domain - polar amino acids Transmembrane domain has non-polar amino acids -- > embedded in the phospholipid bilayer. Hemoglobin = iron + protoporphyrin IX 1 subunit = 2a and 2ß chains in a-helical heme-binding pocket lined by non-polar amino acids.

QId: 166 Pharmacology Metabolism

- Endocrine, Diabetes &

Small quantities of pancreatic lipase leaks into pancreatic capillaries -- > triglyceride conversion to free fatty acids -- > FFA have a toxic and inflammatory effects on the pancreas -- > pancreatitis.

QId: 1328 Pathophysiology Metabolism

- Endocrine, Diabetes &

Metabolic syndrome - insulin resistance --> decreased lipogenesis and increased lipolysis --> increased lipolysis --> increases free fatty acids --> gluconeogenesis and decreased insulin-dependant glucose uptake --> more insulin resistance

QId: 1562 Physiology Metabolism

- Endocrine, Diabetes &

Mutations in neurophysins = AD hereditary hypothalamic diabetes insipidus

QId: 850 Pharmacology Metabolism

- Endocrine, Diabetes &

Insulin degludec - polymer formation at injection site -- > slowed uptake Detemir - fatty acid side chain added to lysine -- > binds to circulating albumin -- > slow release Glargine - pH of 4 -- > microprecipitate formation -- > delayed absorption NPH - crystalline suspension of insulin+protamine+zinc -- > delayed absorption

QId: 1326 Pathophysiology Metabolism

- Endocrine, Diabetes &

TNF-a phosphorylates serine residues of ß part of insulin receptors -- > inhibited downstream regulation -- > insulin-resistance. (Phosphorylation of threonine residues = similar effect).

QId: 1996 Pathology Metabolism

- Endocrine, Diabetes &

People with ß-thalassemia and DM -- > falsely low HbA1c -- > measure glycated serum proteins (fructosamine). Iron, folate and B12 deficiency -- > decreased production of new red cells -- > increased circulation of old cells -- > falsely elevated HbA1c (also seen in diabetic nephropathy). Treatment of vitamin deficiencies -- > more release of new red cells -- > falsely low HbA1c.

QId: 610 Pathophysiology Metabolism

- Endocrine, Diabetes &

Side chain cleavage enzyme involved in steroid synthesis converts cholesterol to pregnenoloone (first enzyme) -- > impaired synthesis of all steroid hormones and accumulation of cholesterol esters -- > progressive damage. DHT required fro fusion of labial folds during male fetal development. 5a reductase deficiency -- > ambiguous genitalia at birth

QId: 579 Pathology Metabolism FGFR-1 = Kallmann syndrome FGFR3 = Achondroplasia

- Endocrine, Diabetes &

QId: 1065 Physiology Metabolism

- Endocrine, Diabetes &

Vitamin D toxicity increases osteoclast activity and bone turnover

QId: 14985 Pathophysiology Metabolism

- Endocrine, Diabetes &

Excess thyroid hormone (either from underlying disorder or exogenous administration) -> increased expression of beta adrenergic receptors -- > cardiovascular complications. Increased SBP, decreased DBP, high-output cardiac failure, angina in susceptible patients from increased contractility, atrial fibrillation.

QId: 1010 Biochemistry Metabolism

- Endocrine, Diabetes &

MODY patients - autosomal dominant, young, non-obese patients; worsens during pregnancy due to insulin resistance, non-progressive even without treatment.

QId: 549 Pharmacology Metabolism

- Endocrine, Diabetes &

Corticosteroids reduce peripheral lymphocyte counts by inhibition of immunoglobin synthesis, stimulation of lymphocyte apoptosis and lymphocyte redistribution from intravascular compartment to lymph nodes, spleen and bone marrow. T cells reduced to a greater degree than B cells.

QId: 1327 Pathophysiology Metabolism

- Endocrine, Diabetes &

Insulin resistance is associated with increased triglycerides and decreased HDL, but NOT increased LDL.

QId: 606 Pharmacology Metabolism

- Endocrine, Diabetes &

Insulin tyrosine kinase receptor has 2 a and 2 ß subunits. a subunit - extracellular, binds insulin. ß subunit - intracellular, has tyrosine domains. Metformin increases insulin sensitivity by activating AMP-activated protein kinase. GLP-1 acts through Gs-coupled receptors (adenylyl cyclase system).

QId: 1809 Embryology Breast

- Female Reproductive System &

All females with Mullerian agenesis should undergo renal ultrasound as up to 50% will have co-existing anomaly.

QId: 11926 Pathophysiology Breast

- Female Reproductive System &

ß-hCG -- > relaxin -- > dilated arterioles -- > increased GFR with unchanged (or even reduced) bladder capacity -- > stress incontinence. Pregnancy hormones decrease urethral tone and relax the pelvic floor muscles -- > incontinence.

QId: 11929 Pathology Breast

- Female Reproductive System &

E6 binds to p53 -- > ubiquination and proteasomal degradation --> uncontrolled cell division and impaired apoptosis of damaged DNA. E7 binds to Rb -- > displaces bound transcription factors -- > uregulated DNA replication and cyclin-mediated cell cycling.

QId: 207 Physiology Breast

- Female Reproductive System &

Menotropin - human menopausal gonadotrophin mimics FSH and triggers the formation of dominant ovarian follicle. Exogenous hCG - a subunit is similar to LH -- > mimics LH surge -- > ovulation induction

QId: 7214 Pathology Nutrition

- Gastrointestinal &

In extramedullary hematopoesis, precursor cells are displaced from the bone marrow and infiltrate the liver and spleen -- > organomegaly.

QId: 369 Pathophysiology Nutrition

- Gastrointestinal &

Albumin level is relatively normal in acute liver injury due to its long half life (20 days).

QId: 1927 Pathology Nutrition

- Gastrointestinal &

Councilman bodies - eosinophilic apoptotic bodies; hepatocytes undergo cytotoxic T cell mediated apoptosis -- > councilman bodies.

QId: 17005 Anatomy Nutrition

- Gastrointestinal &

Greater splanchnic nerve: T5-10 Lesser splanchnic nerve: T9-12 (Sympathetic nerve roots) Pelvic splanchnic nerve: S2-4; parasympathetic

QId: 1136 Microbiology Nutrition

- Gastrointestinal &

Organisms causing disease with small inoculum (10-500): C. jejuni E.histolytica Shigella species G. lamblia Organism causing disease with larger inoculum (10^4 - 10^8): Salmonella Vibrio C. perfringens E. coli

QId: 79 Pathology

- Gastrointestinal & Nutrition

Gallbladder outflow obstruction -- > hydrolysis of luminal lecithins to lysolecithins -- > disruption of protective mucus layer -- > mucosal exposure to detergent action of bile salts -- > chemical irritation and prostaglandin release -- > inflammation -- > hypomotility -- > distention and increased pressure -- > ischemia -- > bacterial invasion

QId: 305 Pathology Nutrition

- Gastrointestinal &

Secretin causes paradoxical increase in gastrin secretion in tumors because of abnormal adenylate cyclase activation.

QId: 7710 Pathology Nutrition

- Gastrointestinal &

H. pylori can only colonize gastric tissue though it causes duodenal ulcer. Duodenal ulcer - colonization of bacteria in gastric antrum -- > decreased somatostatin secretion -- > increased gastrin -- > increased acid secretion -- > ulcer. Gastric ulcer - colonization of bacteria in gastric corpus; not associated with increased acid (normal or decreased); direct mucosal damage and chronic inflammation.

QId: 14880 Anatomy Nutrition

- Gastrointestinal &

Failure of the posterolateral diaphragmatic foramina to fuse = Bochdalek hernia. Herniation of viscera through omental foramen (foramen of Winslow) = lesser sac hernia

QId: 393 Pathology Nutrition

- Gastrointestinal &

HFE protein interacts with the transferrin receptor on the cell surface to facilitate endocytosis of the iron-transferring complex. Once inside the cell, transferrin is degraded and the iron is added to the labile iron pool. In HFE mutation, improper interaction with the transferrin receptor -- > decrease iron uptake -- > sensing of falsely low iron levels -- > increased DMT expression -- > more absorption of iron and decreased hepcidin release from liver -- > increased ferroportin action -- > all leading to IRON OVERLOAD.

QId: 57 Pathology

- Gastrointestinal & Nutrition

Aflatoxin - B1 most common and most toxic. p53 mutations -- > G:C --> T:A transversion

QId: 1547 Pathology Nutrition

- Gastrointestinal &

Alcohol -- > secretion of protein rich fluid from pancreas -- > precipitates and calcifies -> ductal plugs -- > pancreatitis

QId: 358 Pathology Nutrition

- Gastrointestinal &

Bronchopulmonary sequestration = congenital malformation where extra, nonfunctional lung tissue is present without communication to the tracheobronchial tree; can cause recurrent pneumonia

QId: 7215 Pathology Nutrition

- Gastrointestinal &

Pentagastrin is a synthetic gastrin analog that stimulates secretion of gastric acid. Diagnostic agent in medullary carcinoma of thyroid - increases calcitonin secretion on administration and in carcinoid tumour - increases secretion of serotonin.

QId: 8425 Biochemistry Nutrition

- Gastrointestinal &

Leptin = satiety It decreases production of neuropeptide Y, a potent appetite stimulant in the arcuate nucleus of hypothalamus. It stimulates the production of POMC in the arcuate nucleus -- > a MSH produced by cleavage -- > inhibition of food intake In most individuals however, persistent elevation of leptin levels desensitizes the receptor (like insulin resistance).

QId: 306 Pathophysiology Nutrition

- Gastrointestinal &

Systemic mastocytosis - clonal mast cell proliferation occurs in the bone marrow, skin, and other organs. Associated with KIT (CD 117) receptor tyrosine kinase. ? mast cell tryptase -- > histamine release -- > syncope, flushing, hypotension, pruritis and urticaria. Stimulates gastric cells -- > ? gastrin production -- > ulcers; also acid neutralizes pancreatic and intestinal secretions -- > diarrhea and other GI symptoms.

QId: 12062 Pathology Nutrition

- Gastrointestinal &

Dumping syndrome - gastric bypass surgery, pyloric sphincter damage -- > hyperosmolar chyme in the small intestine -- > fluid shift from plasma to intestine -- > diarrhea

QId: 433 Pathophysiology Nutrition

- Gastrointestinal &

Hereditary pancreatitis - mutations in trypsinogen or SPINK1 gene. Trypsin can act as its own inhibitor cleaving it at a second site (other than the one where it activates it own self). Mutation -- > abnormal trypsin -- > inactivating cleavage -- > autodigestion -- > pancreatitis

QId: 1662 Pathophysiology Nutrition

- Gastrointestinal &

Unlike methanol or ethylene glycol, acute ethanol intoxication does NOT usually cause high anion gap metabolic acidosis. Chronic alcoholism can cause ketoacidosis in malnourished patients.

QId: 396 Pathophysiology Nutrition

- Gastrointestinal &

60% of ingested copper = absorbed in stomach and duodenum -- > loosely bound to albumin -- > transported to liver -- > combines with a2 globulin -- > ceruloplasmin. Senescent ceruloplasmin and extra copper secreted into bile and excreted in stool = primary route of excretion.

QId: 132 Pathology Nutrition

- Gastrointestinal &

PAS - periodic acid oxidizes carbon-carbon bonds -- > aldehydes that produce brilliant magenta color upon reacting with the fuchsin-sulfurous acid. Peroxidase staining - used to differentiate subtypes of acute leukemia; horseradish peroxidase - useful in immunoblotting (Western blot). Sudan black/Nile red - identify neutral lipids

QId: 15049 Microbiology Nutrition

- Gastrointestinal &

In C. difficile infection, NAAT is used to detect the toxin B-encoding gene -- > highly sensitive and specific. Enzyme immunoassay is also used to detect toxins (highly specific) but not highly sensitive.

QId: 391 Pathophysiology Nutrition

- Gastrointestinal &

Hemochromatosis manifestion -- > at least 20g of iron deposition.

QId: 434 Pathology Nutrition

- Gastrointestinal &

Alcohol stimulates pancreas to secrete protein rich fluid with decreased water content -- > precipitation of proteins -- > pancreatitis. Alcohol causes RBC macrocytosis due to folate-deficiency, liver disease and/or direct toxicity of alcohol on the marrow.

QId: 278 Microbiology Nutrition

- Gastrointestinal &

Parasitosis-related inflammation and immune-mediated cross-reaction with ganglia --> achalasia in T. cruzi infection.

QId: 2033 Genetics Telomeres contain TTAGGG repeats.

- General Principles

QId: 1436 Biochemistry

- General Principles

Bloom syndrome - helicase dysfunction -- > growth retardation, facial anomalies, photosensitive rash and immunodeficiency. Before the initiation of replication, origin of replication is identified and bound by a multi-subunit protein, the origin recognition complex, which dissociates dsDNA into ssDNA, locally. ssDNA is stabilized by ssDNA-binding proteins; helicase then binds to ssDNA and continues the separation of the DNA by moving the replication fork.

QId: 7791 Genetics

- General Principles

Epistasis - allele of one gene affects the phenotypic expression of alleles in another gene.

QId: 12066 Biochemistry

- General Principles

Irreversible inhibitors - strong covalent bonds with enzyme Competitive inhibitors have high affinity to the enzyme but do NOT decrease the affinity of the substrate to the enzyme.

QId: 542 Immunology

- General Principles

The invariant chain of the MHC II complex acts to guide the molecule during sorting in the Golgi and occupy the binding binding site until it reaches the acidified endosome.

QId: 1248 Biochemistry

- General Principles

Collagen requires hydroxyproline to introduce the ring configuration to cause a kink in polypeptide chain -- > increased rigidity of a helix. Hydroxylysine is requires for cross-linking -- > increasing tensile strength.

QId: 1756 Immunology

- General Principles

Intrinsic apoptotic signals - phosphatidylserine or thombospondin

QId: 12263 Genetics

- General Principles

CAAT box - promoter of transcription in eukaryotic genome; located 70-80 bases upstream from the transcription start site. Hogness box (TATA) - second promoter region right to CAAT; located 25 bases upstream from start site.

QId: 2042 Genetics

- General Principles

Best way to analyse if a gene is being expressed = check if it's being transcribed = mRNA (Northern blotting).

QId: 1438 Genetics

- General Principles

Telomerase RNA component (TERC) - built-in RNA template at the end of chromosomes. Telomerase reverse transcriptase (TERT) - reads TERC and adds TTAGGG DNA sequence repeats. Stem cells have long telomeres and high telomerase activity -- > indefinite proliferation in a controlled manner.

QId: 11930 Biochemistry

- General Principles

Mitochondrial proteins - synthesized in the cytosol and contain specific mitochondrial targeting sequences. Translocases detect these sequences and shuttle the proteins into and between the different mitochondrial compartments. Nuclear proteins - for nuclear proteins to be imported into the nucleus, they must first present a nuclear localization signal to the nuclear pore complexes on the nuclear envelope. Nuclear export requires a different signal. Peripheral membrane proteins - proteins are covalently attached to a hydrophobic lipid anchor (lipidation) so they can be targeted to the plasma membrane.

QId: 1424 Biochemistry

- General Principles

Transition - mutation causing purine -- > purine change Transversion - purine -- > pyrimidine or vice versa.

QId: 1298 Pathology

- Hematology & Oncology

Sepsis -- > DIC as the LPS is a procoagulant

QId: 1160 Pathology

- Hematology & Oncology

Muscle tissue immunohistochemistry - actin, caldesmon or desmin Endothelium - CD34 or vWF

QId: 15299 Pharmacology Oncology

- Hematology &

Palbociclib - CDK 4/6 inhibitors; inhibit activation of cyclin dependent Rb phosphorylation -- > Rb in hypophosphorylated form (active) -- > non-progression of cell cycle.

QId: 2092 Pathology

- Hematology & Oncology

Keratin = alanine+glycine small structure -- > coil tightly large number of hydrogen bonds increased sulfur containing cysteine -- > disulfide bonds -- > more rigidity and toughness

QId: 14772 Pathology Oncology

- Hematology &

Cachexia caused by TNF-a, IL-6 -- > stimulation of ubiquitin-proteasome pathway -- > skeletal muscle degradation -- > wasting.

QId: 1819 Pharmacology Oncology

- Hematology &

MDR genes in tumour cells -- > P-glycoprotein production - a transmembrane protein that functions as an ATP-dependent efflux pump -- > efflux of chemotherapeutic agents, specially hydrophobic agents like anthracyclines. It is normally expressed in intestinal and renal tubular epithelial cells to eliminate foreign particles. Also present in the capillary endothelium of vessels of blood-brain-barrier, prevents penetration of foreign compounds into the CNS.

QId: 341 Pathology

- Hematology & Oncology

Bony metastasis - PB/KTL - lead kettle - prostate, breast, kidney, thyroid, lung.

QId: 892 Pharmacology Oncology

- Hematology &

HbS polymerizes in deoxygenated and dehydrated form. HbF -- > increased oxygen affinity -- > decreased sickling Gardos channel blockers (calcium-dependent potassium channels) --> reduced potassium and water efflux when blocked -- > decreased dehydration -- > decreased polymerization (sickling)

QId: 715 Pharmacology Oncology

- Hematology &

COX 1 - physiologic role like platelet aggregation and protecting GI mucosa. Renal vascular endothelial and smooth muscle cells have COX 1 and COX 2 -- > selective COX 2 inhibitors can also reduce renal function. Aspirin acetylates serine residues of platelet COX enzyme --> irreversible inhibition of plateletaggregation

QId: 58 Pathology

- Hematology & Oncology

HBV and HCV infect hepatocytes -- > increased hepatocyte turnover and generation of local inflammatory cytokines -- > mutations -- > malignant transformation. Additional HBV features: incorporates into host DNA by host topoisomerase I (though not required for replication) -- > insertional mutations in regions that control cell growth and differentiation. Also, it produces HBx, a transcriptional activation of several genes associated with cellular growth and interferes with p53 function.

QId: 2132 Pharmacology Oncology

- Hematology &

UFH has a chain long enough to bind to antithrombin and thrombin to inactivate the complex. LMWH cannot bind to thrombin efficiently -- > poor inactivator of thrombin (mainly inactivates Xa as it requires binding only to AT III and not the factor Xa itself).

QId: 1798 Pathology

- Hematology & Oncology

AML M6 - erythroid precursor cells; elderly patients AML M7 - platelet precursor cells; 1,22 translocation and Downs'

QId: 1797 Pathology

- Hematology & Oncology

Procarcinogens are metabolized by P450 monooxygenase, which is present in the hepatic microsomes and ER of various other tissues. It metabolizes steroids, alcohol, toxins and other substances -- > soluble and easier to excrete. However, also converts pro-carcinogens -- > carcinogens -- > DNA mutations. Glutathione-S-transferase - detoxification of some chemical carcinogens; converts into inactive metabolites.

QId: 1474 Genetics

- Hematology & Oncology

Radiation therapy causes cell death by: DNA double-strand breakage - single-strand breakage can be easily repaired; hence, double-stranded break necessary for cell death. Free radical formation - formed by ionizing water

QId: 1754 Pathology

- Hematology & Oncology

Reactive hyperplasia of lymph node - benign, polyclonal cells; has cell pleomorphism, increased mitosis and nuclear changes. Malignancy of lymph node - Monoclonal lineage of tumour cells. T-cell malignancy - examine for rearrangement of TCR genes; done through PCR or other molecular methods. B-cell malignancy - rearrangement of the genes for immunoglobulin variable regions.

QId: 1084 Pathology

- Hematology & Oncology

Tumor cells detach from neighboring cells through decreased expression of E-cadherins; adhere to basement membrane through increased expression of laminins; invade basement membrane through increased MMPs, cathepsin D protease, etc.

QId: 1240 Biochemistry Oncology

- Hematology &

NADH methemoglobin reductase reduces ferric iron to ferrous iron, regenerating hemoglobin from methemoglobin; deficiency -- > congenital methemoglobinemia. CO reversibly binds to heme.

QId: 787 Physiology

- Hematology & Oncology

Renal tubular cells secrete lactoferrin -- > binds to free iron in urine (recovers for metabolic use)

QId: 16442 Pathophysiology Oncology

- Hematology &

Heat stroke/sever hyperthermia -- > blood shunting away from essential organs to release heat -- > tissue ischemia/necrosis -- > release of tissue factor (procoagulant factors) -- > DIC

QId: 1375 Microbiology Oncology

- Hematology &

Adenovirus has hexon and penton capsomeres on its surface. Rodlike structures (fibers) that project from the penton base are responsible for mediating adsorption to host cells. The cell receptor is a transmembrane protein member of the immunoglobulin superfamily.

QId: 11912 Genetics

- Hematology & Oncology

Telomerase - RNA-dependent DNA polymerase; 2 molecules: human telomerase reverse transcriptase adn telomerase RNA. In human cells, present only is cells that divide rapidly (germ cells, stem cells, etc) >90% cancer cells contain telomerase activity -- > continued proliferation without apoptosis

QId: 1857 Pharmacology Oncology

- Hematology &

MTX undergoes polyglutamation -- > trapping inside cells. This inhibits folic acid and DHF -- > accumulation of DHF polyglutamate inside cells

QId: 1855 Pathophysiology Oncology

- Hematology &

Dactylitis in sickle cell disease is common in the first few years of life as the bones still contain hematopoietic bone marrow.

QId: 1387 Biochemistry Oncology

- Hematology &

Positively charged histidine and lysine in HbA attracts negatively charged 2,3 BPG -- > decreased oxygen affinity. In HbF, histidine is replaced by serine -- > decreased positive charge -- > decreased affinity to 2,3 BPG -- > increased oxygen affinity (to extract oxygen from mother).

QId: 1580 Pathology

- Hematology & Oncology

Folate and B12 deficiency = defective purine and pyrimidine synthesis; RNA and protein synthesis is normal -- > cytoplasmic growth with impaired cell division -- > macrocytosis. Pancreatic insufficiency -- > B12 deficiency as the pancreatic enzymes cleave R factor from B12 -- > B12 binding to intrinsic factor.

QId: 1890 Pharmacology Oncology

- Hematology &

6-MP is activated by HGPRT and inactivated by xanthine oxidase and thiopurine methyltransferase

QId: 1090 Pharmacology Oncology

- Hematology &

Cholestyramine binds warfarin in the intestine, decreasing the therapeutic effect.

QId: 1796 Pathology

- Hematology & Oncology

Treatment of iron-deficiency anemia -- > increased erythropoeisis -- > accelerated release of both mature RBCs and reticulocytes into the bloodstream. These reticulocytes are slightly larger than mature RBCs and though they do not have nuclear remnants, they stain blue for Wright-Giemsa stain due to residual rRNA.

QId: 14983 Pathophysiology Oncology

- Hematology &

Pappenheimer bodies - aggregated iron deposits in RBCs in sideroblastic anemia Howell-Jolly bodies - clusters of DNA remnants in RBCs in hyposplenism/asplenism Heinz bodies - aggregates of denatured hemoglobin in RBCs in G6PD deficiency. Basophilic stippling - precipitated ribosomes in RBCs in thalassemia, alcohol abuse and lead/heavy metal poisoning. Splenic conditioning - removal of excess membrane on RBCs by the macrophages in the red pulp. Post-splenectomy - target cells seen in peripheral smear up to few weeks. Later, macrophages in nonsplenic tissue take up the task of "pruning." Target cells are less prone to osmotic stress than normal RBCs due to excess membrane.

QId: 14956 Pharmacology Oncology

- Hematology &

P-glycoprotein is a multidrug transporter that can be used by cancer cells to pump cytotoxic chemotherapy out of the cell.

QId: 11456 Pathology Oncology

- Hematology &

Leukamoid reaction = neutrophils with Dohle bodies - basophilic peripheral granules (ribosomes attached to ER). Neutrophils may also have toxic granulation and cytoplasmic vacuoles.

QId: 1339 Pathophysiology Oncology

- Hematology &

IV dextrose inhibits PPAR-gamma, a transcription factor that induces synthesis of ALA synthase -- > improvement in symptoms.

QId: 957 Microbiology Oncology

- Hematology &

M. pneumoniae binds to respiratory epithelium by binding through an oligosaccharide (I-antigen) also found on RBCs -- > cross-reactive, cold, IgM antibodies -- > attachment to RBCs, complement system activation -- > intravascular hemolysis.

QId: 15228 Pathology Oncology

- Hematology &

Oropharyngeal tumors due to HPV are more likely to occur in younger individuals, present at an earlier stage, lack mutations to p53 and over-express the tumor suppressor gene p16 (aids diagnosis).

QId: 15706 Pharmacology Oncology

- Hematology &

Acute phase chemotherapy-induced vomiting - due to release of serotonin from intestinal cells -- > give 5HT3 antagonists Delayed phase - due to substance P stimulation -- > neurokinin-1 receptor activation -- > give NK1 receptor antagonists Malignancy-related anorexia - treat with progesterone analogs, corticosteroids or cannabinoids. Malignancy-related hypercalcemia - treat with bisphosphonates Opioid-induced constipation - treat with methylnaltrexone (decreased ability to cross BBB -- > no withdrawal)

QId: 8632 Biochemistry Oncology

- Hematology &

Akt - serine/threonine-specific protein kinase (protein kinase B); seen in receptor tyrosine kinase signal transduction. PTEN - phosphatase and tensin homolog; removes phosphate group from PIP3.

QId: 1101 Microbiology

- Infectious Diseases

Protective antigen of B. anthracis binds to the receptor on macrophages -- > formation of channel -- > delivery of lethal and edema factor into the cell. Lethal factor - zinc metalloproteinase, inhibits MAP kinase signal transduction -- > cell death. Edema factor - calmodulin-dependent adenylate cyclase, increases cAMP concentration -> fluid accumulation within and between cells, suppression of neutrophil and macrophage function.

QId: 46 Microbiology

- Infectious Diseases

Perinatal transmission is most commonly during delivery; transplacental transmission can also occur. Children generally immunotolerant - no symptoms nor elevated liver enzymes. HbeAg levels in mother determines the chances of transmission (viral load), almost all infants affected. Can progress to chronic disease (90% without treatment). Immediate HBV vaccination and immunoglobulin after birth might prevent progression to chronic disease.

QId: 112 Immunology

- Infectious Diseases

Candida - defense by T-lymphocytes and neutrophils; defective lymphocytes = localized infection; defective neutrophils = disseminated infection

QId: 15436 Microbiology

- Infectious Diseases

Chagas cardiomyopathy is caused by chronic, low-grade, parasite-mediated myocarditis -> destruction of cardiac fibres -- > fibrosis -- > dilated cardiomyopathy with apical atrophy. Complications - arrhythmias, ventricular aneurysm with intracardiac thrombus, biventricular heart failure

QId: 14921 Pathology

- Infectious Diseases

Positive APRs - fibrinogen, CRP, ferritin, hepcidin, ceruloplasmin, haptoglobin, von Willebrand factor and complement. ESR indirect measure of positive APRs Negative APRs - albumin, transferrin and transthyretin (prealbumin)

QId: 15453 Microbiology

- Infectious Diseases

Mefloquine destroyes extrahepatic schizonts but is not useful for hepatic schizonts as it gets inactivated in the liver. People taking chemoprophylaxis should continue taking mefloquine for 4 weeks upon returning from the endemic region to ensure that the parasites released from the liver are destroyed when they infect the RBCs.

QId: 1092 Microbiology

- Infectious Diseases

Diphtheria vaccination -- > neutralizing IgG against the binding component (B subunit) of the diphtheria exotoxin.

QId: 1135 Microbiology

- Infectious Diseases

Shigella invades M cells, lyses its containment vacuole and enters the cytosolic compartment -- > induces apoptosis and spreads to adjacent cells via protrusions created through host-cell actin polymerization -- > robust immune response (mainly neutrophils).

QId: 739 Immunology

- Infectious Diseases

Too much IgA can cause disseminated infection of Neisseria species as it does not fix complement and does not allow complement-fixing antibodies (IgM and IgG) to attach and cause lysis.

QId: 15230 Microbiology

- Infectious Diseases

E. histolytica - contact dependent cytotoxicity: amebic lectin binds the host cell, introduces an amebic porin into the host cell membrane and causes cell lysis.

QId: 1409 Microbiology

- Infectious Diseases

Vesicular lesion on hard palate and gums = HSV 1 On buccal mucosa (along with palms and soles) = Coxsackie

QId: 15518 Microbiology

- Infectious Diseases

Disseminated gonococcal infection - triad of polyarthralgia, tenosynovitis and dermatitis/purulent arthritis.

QId: 15566 Microbiology

- Infectious Diseases

Chemotherapy-induced neutropenia -- > invasion of commensal organisms -- > infection (neutropenic fever; no other signs).

QId: 483 Histology

- Infectious Diseases

HPV can infect the true vocal cords as it is covered by stratified squamous epithelium (required for constant repair of surface cells by basal cells coz they undergo constant friction and abrasion).

QId: 560 Microbiology

- Infectious Diseases

Disseminated gonorrheal infection - triad of arthritis, dermatitis and tenosynovitis.

QId: 1025 Microbiology

- Infectious Diseases

Gonococcal LOS is similar in structure to the human cell membrane glycosphingolipids.

QId: 1138 Microbiology

- Infectious Diseases

S. typhi is able to evade destruction via macrophage mediated oxidative burst due to a specialized capsular antigen Vi -- > replicates in macrophages, lymphatic and reticuloendothelial system -- > symptoms. Ulceration of Peyer patches -- > GI bleeding -- > perforation.

QId: 1045 Microbiology

- Infectious Diseases

Neurologic manifestations of measles: Encephalitis - within days Acute disseminated encephalomyelitis - within weeks Subacute sclerosing panencephalitis - within years.

QId: 15255 Microbiology

- Infectious Diseases

V. vulnificus can cause food-poisoning when ingested through contaminated sea food. It can also cause wound infections, particularly in patients with liver disease or iron overload as iron acts as a catalyst -- > exponential growth. Wound infection - rapidly progressive necrotizing fasciitis with hemorrhagic, bullous lesions and septic shock. Treatment - urgent antibiotics, surgery and BP support.

QId: 15113 Microbiology

- Infectious Diseases

Tenofovir mainly secreted by PCT -- > toxicity leads to PCT dysfunction through mitochondrial dysfunction -- > cell damage. Histo - loss of brush border in PCT, GBM denudation, eosinophilic intracytoplasmic inclusions (giant mitochondria). HIV-induced nephropathy - FSGS and interstitial inflammation Hypertensive glomerulosclerosis - vascular thickening, glomerulosclerosis and renal interstitial fibrosis.

QId: 11658 Anatomy System

- Male Reproductive

Right gonadal artery - in front of IVC adn behind ileum Left gonadal artery - behind the left colic and sigmoid arteries and iliac colon. Cross anteriorly over the ureter and run parallel to external iliac vessels and eventually traverse the inguinal canal to supply the testes via the spermatic cord. Internal iliac supplies pelvic wall/viscera, buttock, female reproductive organs, bladder and medial thigh. Internal pudendal supplies anal canal, scrotum and penis. Obturator artery supplies pelvis, bladder and parts of femoral head and medial thigh muscles

QId: 11532 Behavioral science (Multisystem)

- Miscellaneous

Physician burnout - emotional exhaustion, cynicism, depersonalization, decreased sense of personal accomplishment -- > suboptimal patient care and medical error. Physician usually shows lack of concern or callousness toward patients (rather than forgetfulness).

QId: 908 Pathology

- Nervous System

HSV 1 travels through olfactory tracts -- > olfactory lobe i.e. medial temporal lobe; hence, the predilection for temporal lobe encephalitis. Hemorrhagic inflammation -- > elevated erythrocytes in CSF (unlike other meningitis findings).

QId: 1399 Microbiology

- Nervous System

Nerve conduction velocity is NORMAL in botulinum toxin poisoning.

QId: 11576 Pathology

- Nervous System

PNS axon injury - Schwann cells degrade the injured myeline and secrete chemokines to recruit macrophages to clear debris. Also secretes trophic factors -- > effective clearance of debris and regeneration of axon. CNS injury - slow recruitment of microglia due to blood-brain barrier and oligodendrocytes undergo apoptosis -- > defective clearance -- > persitent debris for months together. Astrocytes form glial scar -- > barrier for regeneration.

QId: 1005 Microbiology

- Nervous System

N. meningitidis enetration into CNS is through cerebral capillary endothelial surface and choroid plexus.

QId: 1361 Physiology

- Nervous System

M3 receptors is present on the endothelial surface of peripheral blood vessels; stimulation -- > release and synthesis of NO -- > smooth muscle relaxation -- > vasodilation Elsewhere, it activates Gq receptors -- > Ca2+ release -- > smooth muscle contraction (eg: intestine, detrusor muscle in the bladder, pupillary constriction, exocrine gland secretion, etc).

QId: 592 Pathology

- Nervous System

Parkinson disease - Lewy bodies (a synuclein) Lewy body dementia - intracellular Lewy bodies Huntington disease - aggregates of huntingtin protein Alzheimer disease - ß amyloid core (senile plaques) and hyperphosphorylated tau protein (neurofibrillary tangles) Frontotemporl demetia - hyperphosphorylated tau (Pick bodies) or ubiquitinated TDP-43

QId: 1687 Anatomy

- Nervous System

Spasticity - initial flexion -- > extensor muscle activation due to disinhibition of the stretch reflex; overcome with continued flexion.

QId: 12226 Anatomy

- Nervous System

NE (locus ceruleus) - posterior rostral pons near the floor of the fourth ventricle Dopamine (ventral tegmentum and ScN) - midbrain Dynorphine (opioid) - periaqueductal gray, rostral ventral medulla and dorsal horn of spinal cord.

QId: 146 Pharmacology

- Nervous System

Ca channel blockers in SAH provides protective effects through cerebral vasodilation and possibly decreased calcium-dependent excitotoxicity.

QId: 660 Pharmacology

- Nervous System

The action of an anesthetic depends on the peripheral tissue uptake. If an anesthetic has a very large arteriovenous concentration gradient (wrt peripheral tissues and NOT the brain), more anesthetic agent is needed to saturate the blood to reach the brain -- > slow onset of action.

QId: 1304 Pathology

- Nervous System

Optic gliomas = immature astrocytes with microcystic degeneration and Rosenthal fibers

QId: 8476 Pharmacology

- Nervous System

Migraine - due to activation of trigeminal afferents -- > release of vasoactive neuropeptides (substance P and calcitonin gene-related peptide/CGRP) -- > vasodilation and plasma protein extravasation -- > neurogenic inflammation. Neuronal sensitization also occurs causing the central nociceptive pathways to become more sensitive to painful and non-painful stimuli. Triptans -- > 5-HT1B (on blood vessels) and 5-HT1D (on nerve terminal) -- > inhibit release of vasoactive peptides, promote vasoconstriction and block pain pathways.

QId: 15580 Microbiology

- Nervous System

C. neoformans in the brain clogs the arachnoid villi with yeast antigens and capsular proteins through replication -- > obstructed CSF outflow -- > elevated ICP -- > headache, nausea, vomiting, neck rigidity, papilledema, etc.

QId: 11793 Pathophysiology

- Nervous System

Long-standing rheumatoid arthritis -- > involvement of cervical spine -- > joint destruction with vertebral malalignment (subluxation). Atlantoaxial joint - most often involved as the atlas (C1) has a high degree of mobility relative to the axis (C2).

QId: 15612 Pathophysiology

- Nervous System

Demyelinating neuropathies - DELAYED nerve conduction velocity Axonal neuropathies - REDUCED signal amplitude Myasthenia gravis - muscle stimulation studies -- > decreased motor signal strength with repetitive stimuli Botulinum toxin - muscle stimulation studies -- > decreased motor signal strength that increases with repetitive stimuli.

QId: 15667 Pathology

- Nervous System

Diabetic neuropathy - length-dependent axonopathy (long fibers affected first; eg: feet) Small-fiber injury - positive symptoms (eg: paresthesias, pain, etc). Large-fiber involvement - negative symptoms (eg: loss of proprioception, diminished reflexes, etc).

QId: 1060 Pathology

- Nervous System

Lacunar midbrain strokes -- > CN III involvement because of densely packed fibers. Contralateral superior rectus affected as the subnucleus fibers decussate at this point. Bilateral ptosis - levator palpebrae involvement (both innervated by a single subnucleus).

QId: 1920 Pathophysiology

- Nervous System

UMN lesions - weakness more pronounced in upper extremity extensors and lower extremity flexors; also, upper extremity supination is weaker than pronation -- > pronator drift.

QId: 910 Pathology

- Nervous System

Mutated or absent matrix protein (required for viral assembly) prevents mature virion particles from forming. The virus continues to replicate intracellularly, evading immune response -- > accumulation of viral nucleocapsids within neurons and oligodendrocytes -> intranuclear inclusions -- > inflammation, demyelination and gliosis in many cerebral areas.

QId: 1815 Anatomy

- Nervous System

Parotid gland - CN IX Submandibular and sublingual nerve - CN VII

QId: 2076 Anatomy

- Nervous System

Anterior 2/3 of posterior limb of internal capsule = motor fibers (corticospinal tract). Posterior 1/3 = sensory fibers Involvement usually causes pure motor stroke or sensory motor stroke.

QId: 1268 Pathology

- Nervous System

PAS-positive intracytoplasmic vacuoles are found in conditions involving ion-channel myopathies

QId: 614 Pathology

- Nervous System

Xanthoastrocytoma - astrocytoma in children and young adults; can progress to GBM; has reticulin deposits and chronic inflammatory infiltrates. Colloid cyst - benign tumor located in the third ventricle; cyst formation and rare mitoses; can lead to lethal obstructive hydrocephalus.

QId: 1197 Pharmacology

- Nervous System

Phenytoin -- > increased expression of PDGF -- > stimulation of gingival macrophages -> proliferation of alveolar bone and gingival cells. Effects on cerebellum and vestibular system -- > ataxia and nystagmus.

QId: 1318 Physiology

- Nervous System

Spatial summation - multiple neurons stimulate a post-synaptic neuron -- > action potential Temporal summation - a single neuron sends multiple sequential stimuli -- > action potential Myelination of neuron -- > decreases membrane capacitance (amount of charge stored by the membrane) and increases membrane resistance (reduces charge leakage through the membrane) -- > increased length constant and decreased time constant. Demyelination reverses these processes.

QId: 919 Pathology

- Nervous System

Multiple sclerosis histo - plaques characterized by perivenular inflammatory infiltrates made up primarily of autoreactive T lymphocytes and macrophages against myelin components -- > disruption of BBB -- > infiltrating macrophages containing myelin debris and recruitment of B cells to perivascular spaces -- > myelin-specific antibodies.

QId: 1741 Anatomy

- Nervous System

Chemotherapy agents -- > intestine epithelial destruction -- > stimulation of 5-HT3 receptors -- > vagal afferent stimulation reaching area postrema in medulla -- > vomiting. Directly stimulate area postrema by causing local release of substance P, activates NK1 receptors -- > vomiting.

QId: 355 Pharmacology

- Nervous System

Focal onset seizures - CBZ, lamotrigine, levetiracetam, phenytoin (Phenytoin and CBZ can also be used in seizures with secondary generalization). Generalized onset seizures - levetiracetam, valproate; absence - ethosuxamide and valproate.

QId: 11462 Pathology

- Nervous System

High-frequency stimulation of the ventral intermediate nucleus of the thalamus may reduce thalamic excitation and lessen excessive movements in patients with medically intractable essential tremor.

QId: 11574 Pathology

- Nervous System

Rubrospinal tract = upper limb flexor predominance Vestibulospinal tract = extensor predominance Cortical inhibition to red nucleus but not as much to vestibular nucleus.

QId: 11949 Pathology Exposure

- Poisoning & Environmental

Lead was eliminated from gasoline in 1985 and from paint in 1977. Houses built before 1978 predisposes to lead poisoning

QId: 791 Pathophysiology Puerperium

- Pregnancy, Childbirth &

Sarcoma botryoides is a rhabdomyosarcoma in young girls; jellylike cystic appearance and arises from the bladder or vaginal mucosa.

QId: 11838 Behavioral science Abuse

- Psychiatric/Behavioral & Substance

Benzodiazepines are avoided in patients with a history of substance abuse.

QId: 11577 Pharmacology Abuse

- Psychiatric/Behavioral & Substance

Naltrexone is the first line of treatment for alcohol use disorder; inhibits rewarding and reinforcing effects of alcohol; long acting depot injection for nonadherent individuals. Acamprosate - NMDA receptor modulation Disulfiram - second-line as the effectiveness depends on supervised administration.

QId: 11603 Behavioral science Abuse

- Psychiatric/Behavioral & Substance

Psychodynamic psychotherapy - developing insight into unresolved conflicts and the influence of past relationships on current life situations. ("Dynamic" Jake in Brooklyn 99). Supportive psychotherapy is bolstering adaptive psychological defenses to help individuals cope with acute crises or chronic psychiatric illness.

QId: 2001 Pharmacology Abuse

- Psychiatric/Behavioral & Substance

Metyrosine blocks the rate-limiting step of catecholamine synthesis (tyrosine hydroxylase) -- > sympatholytic effects Reserpine blocks monoamine entry into presynaptic vesicles -- > sympatholytic effects.

QId: 15644 Behavioral science Abuse

- Psychiatric/Behavioral & Substance

REM sleep behavior disorder - loss of normal REM sleep atonia -- > enactment of dreams

QId: 11870 Behavioral science Abuse

- Psychiatric/Behavioral & Substance

Erectile dysfunction - psychological, diabetes or disorders affecting nerve function. Premature ejaculation - prostatitis, thyroid disorders

QId: 7752 Behavioral science Abuse

- Psychiatric/Behavioral & Substance

Orbitofrontal cortex - associated with limbic system -- > behavioral and emotional changes (bilateralinvolvement) Prefrontal cortex - dysexecutive syndrome characterized by inability to carry out motivation, organization, planning and purposeful action.

QId: 774 Pharmacology Abuse

- Psychiatric/Behavioral & Substance

Long term activation of mu-opioid receptors on nociception-transmitting neurons -- > increased pain sensitivity due to: Increased turnover of inhibitory receptors (downregulation) and decoupling of receptors from their second messenger system (receptor decoupling) Upregulation of excitatory N-methyl-D-aspartate receptors Opioid-induced hyperalgesia

QId: 11899 Behavioral science Abuse

- Psychiatric/Behavioral & Substance

Delirium due to an underlying medical cause which causes the patient to be a harm to self or others can be treated with haloperidol (NOT benzodiazepines) till the underlying disorder gets corrected.

QId: 962 Microbiology Care

- Pulmonary & Critical

Capsulated H. influenza binds to H factor, a circulating regulator protein in humans which normally prevents complement deposition on human cells -- > defective opsonization -- > evades phagocytosis

QId: 7661 Physiology Care

- Pulmonary & Critical

Patients weaning off of ventilator = weak respiratory muscles -- > hypoventilation -- > triggered respiratory center -- > tachypnea. Tachypnea with constant minute ventilation -- > low tidal volumes. Low tidal volumes -- > increased fraction of dead space ventilation.

QId: 1876 Pathology Care

- Pulmonary & Critical

In fat embolism, some fat globules escape the lungs via precapillary arteriovenous shunts that open due to increased pulmonary artery pressure (obstruction from embolus) -- > emboli through pulmonary veins -- > systemic circulation -- > CNS symptoms and also in dermal capillaries -- > petechial rash due to RBC extravasation.

QId: 8260 Pathophysiology Care

- Pulmonary & Critical

Elastic resistance - increases at high lung volumes and decreases with respiratory rate -- > rapid, shallow breathing in restrictive diseases Airflow resistance - increases at high respiratory rate (turbulence) and decreases at high lung volumes (diameter) -- > increased at low lung volumes (decreased airway diameter) -- > slow, deep breathing in obstructive diseases

QId: 11900 Pathophysiology Care

- Pulmonary & Critical

Reduction in expiratory reserve volume is the most common indicator of obesity-related disease.

QId: 1881 Pathology Care

- Pulmonary & Critical

Hemosiderin-laden macrophages -- > CHRONIC lung congestion. Acute pulmonary edema - engorged capillaries and alveoli with acellular pink material.

QId: 964 Microbiology Care

- Pulmonary & Critical

Fimbriae in H. influenza help in attachment to endothelial cells during colonization of respiratory tract but are NOT a major virulence factor. a-hemolysin - S. aureus destroys cell membrane of RBC and WBC. Hyaluronidase - S. aureus, S. pyogenes, C. perfringens digest ECM and enhance their ability to spread.

QId: 12082 Pathophysiology Care

- Pulmonary & Critical

CD4+ - asthma CD8+ - COPD

QId: 1249 Biochemistry Care

- Pulmonary & Critical

Elastic property of elastin due to: Cross-linking by desmosine cross-links (lysyl oxidase oxidatively deaminates lysine residues) High content of non-polar amino acids (glycine, alanine, valine)

QId: 484 Pathology Care

- Pulmonary & Critical

Anti-proteinases - a-1 antitrypsin, a-2 macroglobulin, tissue inhibitors of MMPs (TIMPs) Neutrophil elastase inhibited by a1 antitrypsin; macrophage elastase inhibited by TIMPs. Each elastase can degrade each other's inhibitor -- > deletarious effects when present together

QId: 1216 Microbiology Care

- Pulmonary & Critical

M. tuberculosis are arranged in long, slender, serpentine cords due to the presence of a hydrophobic surface glycolipid called cord factor. Cord factor = 2 mycolic acid molecules + disaccharide trehalose -- > bound form -- > trehalose dimycolate. Cord factor -- > cylindrical micelles around the organism -- > prevent macrophage-mediated destruction within phagolysosome -- > VIRULENCE. Also forms a highly toxic crystalline monolayer on hydrophobic surface -- > caseating granulomas.

QId: 1666 Microbiology Care

- Pulmonary & Critical

Influenza virus attacks the tracheobronchial epithelium and results in decreased cell size and loss of cilia -- > secondary bacterial colonization and infection.

QId: 15126 Pharmacology Care Pirfenidone - inhibits TGF-ß Nintedanib - tyrosine kinase inhibitor of PDGF, FGF, VEGF Reslizumab - IL-5 inhibitor Roflumilast - PDE-4 inhibitors (COPD)

- Pulmonary & Critical

QId: 666 Pathology Care

- Pulmonary & Critical

IPF - loss of type 1 pneumocytes and hyperplasia of type 2 pneumocytes. ARDS - loss of type 1 and 2 pneumocytes with fibroblast proliferation in later stages

QId: 1194 Pharmacology Care

- Pulmonary & Critical

Enoxaparin (4-5 hrs) preferred during pregnancy due to longer half-life and lesser need for monitoring Unfractionated heparin (half-life 1-2 hrs) used during labor due to immediate discontinuation of anticoagulation and prevention of bleeding risks. Dabigtran and Apixaban - fetal abnormalities in animal studies

QId: 552 Pathology Care

- Pulmonary & Critical

Pulmonary hamartoma (most common location for a hamartoma) - also called pulmonary chondroma. Made up of hyaline cartilage, fat, smooth muscle and clefts lined by respiratory epithelium

QId: 13402 Microbiology Care

- Pulmonary & Critical

Viral infections are more common triggers than bacterial infection for COPD exacerbation. Green sputum during the exacerbation is caused by release of myeloperoxidase from neutrophils and can be present in either viral or bacterial infection.

QId: 8257 Microbiology Care

- Pulmonary & Critical

Hyponatremia in Legionella - possibly due to SIADH, impaired reabsorption from proximal tubule due to direct effect, cytokines or natriuretic peptide.

QId: 1919 Pathophysiology Care

- Pulmonary & Critical

Restrictive lung diseases divided into intrinsic and extrinsic causes. Intrinsic has reduced DLCO.; eg: interstitial lung disease Extrinsic has normal DLCO; eg: obesity, neuromuscular disease, etc.

QId: 844 Anatomy

- Pulmonary & Critical Care

Intercostal vessels and nerve lie along the subcostal groove. Thoracentesis should be performed just above the upper border of the rib to prevent injury.

QId: 795 Pathology Care

- Pulmonary & Critical

Pulmonary alveolar proteinosis - associated with cigarette smoking, lipoproteinacious material within the alveoli.

QId: 15155 Pathophysiology Care

- Pulmonary & Critical

Occupational asthma - immunolgic and non-immunologic causes Immunologic - IgE mediated; eg: formaldehyde, amines, dyes. Non-immunologic- large exposure of irritant -- > denudation of airway mucosa -- > persistent inflammation, loss of epithelial relaxation factors and mast cell degranulation; eg: chlorine and ammonia

QId: 481 Physiology Care

- Pulmonary & Critical

Resistance inversely proportional to cross-sectional area. Trachea - small cross-sectional area -- > high resistance Medium-sized bronchi - smaller cross-sectional area -- > higher resistance Terminal bronchioles - large cross-sectional area -- > low resistance Alveoli - massive cross-sectional area -- > essentially zero!

QId: 978 Pathophysiology Electrolytes

- Renal, Urinary Systems &

PTHrP closely resembles PTH at the bioactive amino-terminal region -- > increased bone resorption, decreased renal excretion and increase renal excretion of phosphorus. PTHrP does NOT significantly increase 1,25-dihydroxyvitamin D production due to structural differences after the first 13 amino acids. Malignancy-associated hypercalcemia due to humoral hypercalcemia of malignancy is more common (80%) than due to osteolytic lesions.

QId: 15239 Pathophysiology Electrolytes

- Renal, Urinary Systems &

Hyperfiltration - Hyperglycemia -- > increased glucose reabsorption along with increased sodium reabsorption -- > decreased sodium delivery to macula densa -- > tubuloglomerular feedback mechanism activated -- > increased GFR -- > glomerular hypertrophy. Incipient DN - Over time, there is mesangial expansion, glomerular basement membrane thickening, arteriolar hyalinosis, podocyte expansion -- > microalbuminuria. Overt DN - mesangial nodules, tubulointerstitial fibrosis, overt proteinuria and decreased GFR.

QId: 15250 Pathology Electrolytes

- Renal, Urinary Systems &

Atheroembolic disease is due to cholesterol dislodging from large vessels, usually post an invasive vascular procedure (eg: coronary angiography, aortic surgery). Commonly involved organs - kidney, skin (blue toe, livedo reticularis), GI tract (bleeding, infarction) and CNS (stroke, amaurosis fugax). Pulmonary circulation RARELY involved.

QId: 817 Pathology Electrolytes

- Renal, Urinary Systems &

Higher calcium intake -- > paradoxical decrease in urinary calcium. Calcium in the gut binds with oxalate -- > excreted in feces -- > less available to get absorbed and excreted in urine. Potassium is reabsorbed with citrate in the renal tubules. Higher potassium intake -- > lesser reabsorption -- > more citrate in urine -- > lesser stones.

QId: 2010 Physiology Electrolytes

- Renal, Urinary Systems &

Serum concentration at which glucose appears in urine = 200 mg/dL Serum concentration at which the transporters in the renal tubules are saturated = 375mg/ dL

QId: 1554 Physiology Electrolytes

- Renal, Urinary Systems &

100% K+ filtered through Bowman's space. 2/3rd of that reabsorbed in PCT 25-30% of left over absorbed in TAL of Henle Absorption in PCT and loop of Henle takes place irrespective of serum K+ level. Main regulation takes place at collecting duct.

QId: 15273 Physiology Electrolytes

- Renal, Urinary Systems &

Renal stenosis -- > activation of RAAS -- > improved GFR and filtration fraction but still NOT enough to normalize. Unaffected kidney (in unilateral stenosis) is exposed to elevated systemic pressures -- > pressure natriuresis.

QId: 1559 Physiology Electrolytes

- Renal, Urinary Systems &

Urea is filtered through the glomerulus, passively reabsorbed in PCT and inner medullary collecting ducts and passively secreted by the thin regions of the loop of Henle. Remainder of the nephron is impermeable to urea. 10-70% of filtered urea load is excreted depending on the urinary flow rate and concentration. Urea clearance < GFR

QId: 11786 Immunology Electrolytes

- Renal, Urinary Systems &

Most other cells have an alternative pathway for purine synthesis that lymphocytes lack (mainly dependent on IMP) -- > mycophenolate is relatively specific for suppression of B and T cells.

QId: 11945 Pharmacology Electrolytes

- Renal, Urinary Systems &

EPO -- > increases risk of thrombosis, stroke and BP (possibly due to direct activation of endothelial and smooth muscle cells through EPO receptors).

QId: 1680 Anatomy Electrolytes

- Renal, Urinary Systems &

Proximal ureter - supplied by renal artery Distal ureter - superior vesical artery Middle ureter - variable; branches from gonadal, common and internal iliac, aorta and uterine arteries.

QId: 1663 Pathology Electrolytes

- Renal, Urinary Systems &

Uremia -- > poor peripheral conversion of T4 to T3 -- > functional hypothyroidism

QId: 1211 Pharmacology Electrolytes

- Renal, Urinary Systems &

Anaestheisa and analgesia -- > over-distension of the bladder, a decreased micturition reflex, decreased contractility of the bladder detrusor muscle and incomplete emptying -> retention.

QId: 721 Pathology Sports

- Rheumatology/Orthopedics &

Osteomyelitis common in children; seen in the metaphysis of long bones as it has slow-flowing, sinusoidal vasculature that is conducive to microbial passage. Adults are not as susceptible due to anatomical changes owing to fusion of the epiphysis. Osteomyelitis of the vertebrae through hematogenous spread is seen in adults.

QId: 8671 Anatomy Sports

- Rheumatology/Orthopedics &

Femoral nerve injured due to retroperitoneal hematoma or abscess as it passes laterally between psoas and iliacus muscle; also, during surgery/childbirth, trauma (pelvic fracture). Obturator nerve - pelvic surgery Peroneal nerve - compression of the nerve at proximal fibula (eg: leg casting). Tibial nerve - knee trauma and tarsal tunnel syndrome. Superior gluteal nerve - injection at wrong site

QId: 15629 Pathology Sports

- Rheumatology/Orthopedics &

Inflammation -- > antibodies against citrullination -- > synovial hyperplasia through activated T-cell recruitment of mononuclear cells -- > relative hypoxia -- > production of hypoxia-inducible factor 1 and VEGF by local macrophages and fibroblasts -- > synovial angiogenesis. Over time, granulation tissue, synovial cells and inflammatory cells all form a pannus, which erodes the cartilage and the subchondral bone. Ossification of the pannus can also occur -- > ankylosis.

QId: 15597 Pathology Sports

- Rheumatology/Orthopedics &

Atlantoaxial subluxation is common in inflammatory disorders like rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, etc.

QId: 639 Physiology Sports

- Rheumatology/Orthopedics &

IGF - decreases collagen degradation by inhibiting MMP-13 TGF-ß - increases collagen synthesis and decreases bone resorption.

QId: 1382 Physiology Sports

- Rheumatology/Orthopedics &

Resting membrane potential = mainly efflux of K+ ions (-80 mV) and little influx of Na+ ions (+60 mV) -- > RMP of -70 mV

QId: 11749 Pharmacology Sports

- Rheumatology/Orthopedics &

Azathioprine and 6-MP are degraded into inactive metabolites by xanthine oxidase and thiopurine methyltransferase.

QId: 295 Pathophysiology Sports

- Rheumatology/Orthopedics &

Atrophy at cellular level - decreased mitochondria and ER.

QId: 11564 Pharmacology Sports

- Rheumatology/Orthopedics &

Sclerostin is a glycoprotein produced by osteoclasts. It inhibits osteoblast bone formation. Romosozumab binds sclerostin -- > increased osteoblast activity.

QId: 11770 Pathophysiology Sports

- Rheumatology/Orthopedics &

B-cell activating factor (BAFF) - TNF ligand family; inadequate levels -- > immunodeficiency; high levels -- > autoimmune diseases like SLE.

QId: 8523 Pharmacology Sports

- Rheumatology/Orthopedics &

Monoclonal antibody - mab Receptor molecule - cept Kinase inhibitor - nib

QId: 10464 Behavioral science (Ethics/Legal/Professional)

- Social Sciences

Patient-physician relationship, if already terminated --> personal relationship. Do NOT terminate a physician-patient relationship for the sole purpose of dating. Dating is unethical in psychiatric patients even after termination due to the nature of evaluation.

QId: 1128 Behavioral science (Ethics/Legal/Professional) Vegetative state - state of wakefulness without awareness

- Social Sciences