Comprehensive Basic Science Exam (CBSE) Review Set I

Chagas Disease Answer- Caused by Trypanosoma cruzi parasite passed in the feces of Reduviidae/kissing bug Penetrates broken skin or intact mucous membranes forming a pseudocyst releasing inflammatory infiltrates into myocytes; stains with Giemsa & Wright Romana sign occurs when portal of entry is the conjunctiva or eyelid May resulting in: Enlarged heart- CHF, sudden cardiac arrest Enlarged esophagus- difficulty swallowing Enlarged colon- abdominal pain or constipation Treat with benznidazole or nifurtimox Monocytes Answer- cell with half-moon shaped nucleus that participates in phagocytosis Chronic graft rejection Answer- multifactorial but typically involves arteriosclerosis HLA-B27 Answer- PAIR: Psoriasis Ankylosing spondylitis- chronic synovitis destroying cartilage typically in young men Inflammatory bowel dz- Crohn's & UC Reactive Arthritis- Reactive Arthritis Answer- Arthritis as a reaction to a bacterial infection such as Campylobacter, Chlamydia, Salmonella, Shigella, or Ureaplasma. Associated with conjunctivitis & uveitis Gaucher (Type 1) Answer- AR Lysosomal storage disease Accumulation of sphingolipid glucocerebroside Most common Wrinkled tissue paper I Cell disease Answer- Failure of Golgi apparatus to phosphorylate mannose 6- phosphate the marker to export enzymes to lysosomes resulting in accumulation of lysosomal enzymes in serum Nitroblue tetrazolium test Answer- Aqualitative test to determine defects in NADPH oxidase Negative: CGD Positive: Acute Hepatitis, Mono CGD (chronic granulomatous disease) Answer- inability to produce NADPH oxidase; susceptible to Cat + organisms; elevated neutrophils w/ normal T cell Gp91 phox subunit: heme binding subunit of superoxide generating NADPH Treat with interferon gamma Clarithromycin (macrolide) Answer- ADR of metallic taste & GI Codeine Answer- ADR resp. depression, euphoria, & constipation Cyclobenzaprine Answer- Structurally similar to TCAs w/ anticholinergic side effects used for relief of muscle spasms May exacerbate glaucoma Naproxen Answer- ADR of GI & renal (in elderly) Timolol Answer- Used in HTN & glaucoma; ADR of bradycardia & worsening asthma Bacterial vaginosis Answer- Sloughed mucosal cells = clue cells Trichomoniasis Answer- Cilated, motile trophozoites w/ corkscrew-like motility Autism Answer- Lack of eye contact, verbal communication, & separation anxiety; repetitious behavior Emphysema Answer- Decreased FEV1/FVC ratio, normal FVC; TLC, FRC, & RV increase Parathyroid hormone(PTH) vs phosphate in hypercalcemia Answer- PTH: rapid & direct Phosphate: slow & indirect ANP: Answer- Afib, Ch-1p, NPPA gene mutation causing binding interference,- decrease cGMP Failure of development of 3rd or 4th pharyngeal pouches Answer- DiGeorge syndrome (CATCH 22): truncus arteriosus & agenesis of parathyroid glands May also be associated w/ failure of thymus to develop - T lymphocytes w/ CD3 marker Huntington disease Answer- PCR is the most common method to est. # of CAGs Both the coding & template strands bind the forward & reverse primers on 3' end Pyrmidine Dimers Answer- BRAF gain of function mutation causing covalant thymine (or Cystine) bonds normally repaired thru NER in the G1 phase by endonuclease recognition then excision (DNA polymerase then fills; ligase then reseals) Xeroderma pigmentosum Answer- Mutation of NER endonuclease from UV radiation disrupting DNA replication due to the oligonucleotides remaining damaged DNA Polymerase I Answer- Removal of both leading & lagging RNA primers 5' to 3' (unique) Proofreading of mismatch nucleotides via 3' to 5' exonuclease & elongation of lagging strand 5' to 3' (universal) Topoisomerase Answer- Enzyme that functions in DNA replication, helping to relieve strain in the double helix ahead of the replication fork. Teniposide Answer- Topoisomerase II inhibitor acting in the S phase & G2 phase: S phase: prevents proper unwinding of supercoils & reannealing of DNA G phase: Permanent breaks in both strands of DNA preventing transcription & repair inducing cell cycle arrest Cytarabine Answer- Antimetabolite inhibiting DNA polymerase, arresting cells solely in S phase Fluoroquinolones ( -floxacin) Answer- Bactercidal: direct inhibition of topoisomerase 2 & 4 halting DNA replication as 1st line treatment of uncomplicated pyelonephritis; older for gram negative & aerobic, newer more broad spectrum Contraindicated in LQTS with ADR of torn achilles Long QT syndrome Answer- Rare inborn heart condition in which delayed repolarization of the heart following a heartbeat increases the risk of episodes of torsade de pointes and other life threatening arrhythmias. Prolongation of the QT interval is a diagnostic of the condition. KCNQ1 and KCNE1 Romano-Ward syndrome Answer- AD inherited congenital long QT syndrome No deafness Increased risk for SCD due to Torsades (polymorphic ventiruclar tachycardia) Jervell and Lange-Nielsen syndrome Answer- AR inherited congenital long QT syndrome with congenital sensoneural deafness Increased risk for SCD due to Torsades Telemorase Answer- Carries its own RNA template at 3' for prevention during DNA replication Salicylate (Aspirin) toxicity Answer- Mixed acid base disorder with: Early phase respiratory alkalosis, low PaCO2 Late phase metabolic acidosis, low HCO3 Normal pH Increased conversion of acteyl-CoA to ketoacids & pyruvate to lactate Lung adenocarcinoma Answer- Peripheral glandular tumor with mucin & papillary components; biopsy for efficacy of therapy Presents in young, female, nonsmokers, with signet ring, EML4-ALK or EGFR & KRAS Signet Ring Answer- Cell with a large vacuole, seen predominantly in carcinomas. Most frequently associated with stomach cancer, but can arise from prostate, bladder, gallbladder, breast, colon, ovarian stroma and testis Scalded Skin Syndrome Answer- S. Aureus release of exofoliative toxin A causing desmosomal keratinocyte cleavage in S. Granulosum Causing B. Impetigo: Nikolsky positive blistering brown rash with flaccid bullae that easily slough off Pemphigus Vulgaris Answer- Cancer Anorexia- Cachexia syndrome Answer- 3 part MOA resulting in decreased calorie intake & hypermetabolic state resulting in significant weight loss 1. Cytokines IL-1, IL-6, INF-y, & TNF-a stimulate NfKb that activates ubiquitin proteasome pathway 2. TNF-a also mediates appetite suppression 3. Lipase activation causes reduction of body fat Ubiquitin-proteasome pathway Answer- Myosin chains undergo degradation increasing catabolism Isosorbide Mononitrate Answer- Unlike other nitrates does NOT undergo 1st pass metabolism by the liver w/ nearly 100% bioavailability, providing means of oral treatment for preventation of angina by CAD thru dephosphorylation of myosin light chains Itraconazole (Sporanox) Answer- Antifungal that inhibits synthesis of ergosterol; metabolized by CYP450 Has a low pKa & requires a low gastric pH for dissolution & absorption; PPIs can result in low bioavailability due to gastric pH changes not CYP450 Pantoprazole Answer- PPI with little effect on CYP450 metabolism Medications with high pKa Answer- - Amphetamines - Phenytoin - Allopurinol - Propylthiouracil histone deacetylation Answer- Charged ionic attraction between positive lysine residues & negative DNA occurs thru the removal of acetyl groups by histone deacetylase; resulting in DNA histones binding more tightly, restricting transcription C. Diphtheria Answer- Produces AB toxin that inactivates ribosomal translocation, ribosomes moving by triplets on mRNA in 3' direction, during elongation phase by adding ADP-ribose to EF-2 Presents as grayish white pseudomembranes, severe lymphadenopathy, sore throat, fever, & malaise in unvaccinated Pulmonary Artery HTN Answer- Increased RV afterload that can lead to cor pulmonale Harder to eject blood during systole causing delayed closure of pulmonary valve- wide/fixed S2 split Increased velocity when pulmonary valve does close from increased diastolic pressure- loud P2 Cortisol Answer- BIG fib Increased: - BLOOD PRESSURE - INSULIN RESISTANCE - GLUCONEOGENESIS decreased: - fibroblast - immune/inflammation - bone formation Cocaine Answer- Potential anesthetic mediated by Sodium channel blockade that binds to presynaptic monoanime transporters decreasing reuptake of norepinephrine Also works as an indirect sympathomimetic on both alpha & beta adrenergic receptors Cisplatin, carboplatin Answer- Alkylating agent--cross-links DNA--decreased DNA and RNA synthesis used mostly in GI tumors ADR = nephrotoxicity, otoxicity, "plates in your ears and kidneys" Mitigate nephrotoxicity by using Amifostine (scavenger of free radicals) Clomiphene Answer- Nonsteroidal estrogen receptor blocker for the treatment of PCOS & anovulation thru continued release of FSH & LH Cyclophosphamide Answer- alkylating agent used to treat cancers ADR: Reduce toxicity with Mesna Cyclosporine Answer- Binds cyclophilin inhibiting calcineurin that promotes interleukin−2 synthesis, suppressing T cells reducing risk of transplant rejection (not myelosuppressant) ADR: hirsutism, gingival hyperplasia, hyperlipidemia, HTN, nephrotoxicity (dose−limiting), & seizures (overdose) Anterior Pituitary hormones Answer- FLAT PEG FSH, LH, ACTH, TSH Prolactin, Endorphins, GH Chediask- Higashi Syndrome Answer- Decreased phagocytosis from recessive mutation of lysosomal regulators resulting in recurrent pyogenic infections w/ albinism Carnitine Shuttle Defect Answer- Impaired transport of LCFAs into the mitochondrial matrix, the substrate needed for B-oxidation Resulting in toxic accumulation & hypoketonemia Zellweger syndrome Answer- Defect in peroxisome formation preventing catabolism of very long chain FA (VLCFAs) or branched-chain FAs Resulting in fat accumulation & inability to form myelin causing hypotonia, hepatomegaly, & facial grimacing MEN1 syndrome Answer- Inherited failure of tumor supressor menin resulting in parathyroid, pancreas, & pituitary tumors Zollinger-Ellison syndrome Answer- hypersecretion of gastric acid that produces peptic ulcers as a result of a non-beta-cell tumor of the pancreatic islets MEN2 Answer- Inherited variation of proto-oncogene RET (specific for neural crest & TK rec) resulting in parathyroid tumors, pheochromocytoma, & medullary thyroid cancer MEN3 Answer- Inherited variation of proto-oncogene RET resulting in marfanoid, megacolon, mucosal neuroma, & medullated cornea generalized edema (anasarca) Answer- Mediated by cytokines TNF-a and IL-6 Base Excision Repair (BER) Answer- A DNA repair pathway that involves excision of a damaged base by DNA glycosylase Followed by cleavage of the DNA backbone adjacent to the site by an AP endonuclease Nick translation, DNA polymerization, and ligation complete the repair Daptomycin Answer- Bactericidal antibiotic that causes potassium efflux & rapid membrane depolarization inhibiting intracellular synthesis of DNA, RNA, & proteins ADR: creatine phosphokinase & rhadomyosis, especially with concurrent use of statins Vancomycin alternative for MRSA but NOT to used with concomitant S. Aureus pneumonia because inactivated by surfactant & low lung pentration Tryptophan Answer- tRNA: 3' ACC 5' mRNA: 5' UGG 3' encoded by only 1 codon tRNA acceptor stem Answer- 5' CCA 3': ATP dependent binding of amino acid catalysed by aminoacyl-tRNA synthase