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1
Q

Common causes of bacterial meningitis

A

Streptococcus pneumoniae (Gram + cocci - lancet shaped diplococci)

Listeria monocytogenes (Gram + rods)

Neisseria meningitidis (Gram - cocci - bean shaped diplococci)

Escheria coli (Gram - rods)

Haemophilus influenzae (Gram - coccobacilli)

2
Q

Histone H1

A

located outside of the nucleosome core and helps to package nucleosomes into more compact structures by binding and linking DNA between adjacent nucleosomes.

3
Q

Androgenetic alopecia

A

Most common cause of hair loss in both males and females.

Polygenic inheritance (influenced by multiple genes) with variable penetrance.

4
Q

Otitis media causing organisms

A

most common:

Streptococcus pneumoniae

Haemophilus influenzae

Moraxella

Recurrent infections with these organisms indicate humoral immunodeficiency.

5
Q

Severe Combined Immune Deficiency (SCID)

A

Recurrent infections caused by bacteria, viruses, fungi, and opportunistic pathogens as well as failure to thrive and chronic diarrhea within the first year of life.

Profound hypoplasia of both B-lymphocyte and T-lymphocyte tissue.

Lymphopenia and hypogammaglobulinemia.

6
Q

Pneumocystis and chronic mucocutaneous candidiasis

A

associated with underlying T-cell deficiency

7
Q

Charcot-Bouchard aneurysms

A

Associated witih hypertension

Located: Basal ganglia, cerebellum, thalamus, pons

Size < 1mm

Result of rupture: intracerebral hemorrhage

Symptoms: progressive neurologic deficits, headache

8
Q

Saccular (berry) aneurysms

A

Associated with ADPKD, Ehlers-Danlos syndrome, hypertension.

Located: Circle of Willis

Size: variable, 2-23mm

Result: subarachnoid hemorrage

Symptoms: sudden severe headache, focal neurologic deficits uncommon

9
Q

Vitamin A Toxicity

A

Subdivided into:

Acute - NV, vertigo, blurred vision.

Chronic - alopecia, dry skin, hyperlipidemia, hepatotoxicity, hepatosplenomegaly, and visual difficulties

Teratogenic - microcephaly, cardiac anomalies, fetal death

Intracranial hypertension, skin changes, hepatosplenomegaly

10
Q

Niacin Deficiency

A

3 D’s of pellagra: dementia, dermatitis, diarrhea

11
Q

Where is body’s satiety center located?

A

Ventromedial nucleus of the hypothalamus.

Neurons here detect glucose elevations and signal satiety.

Lesions cause hyperphagia and obesity.

Rage/savage behavior sometimes noted.

Most commonly caused by tumor invasion.

12
Q

Lateral Nuclei of the hypothalamus

A

signals hunger.

lesions would cause one to lose desire to eat

13
Q

Suprachiasmatic nuclei

A

above the optic chiasm

receive visual input from the retina via the optic tract.

regulate circadian rhythms by relaying light information to other hypothalamic nuclei and to the pineal gland

14
Q

Anterior hypothalamic nuclei

A

when body temperature rises, it signals cooling by stimulating the parasympathetic nervous system to produce vasodilation and sweating.

Lesions cause uncontrolled hyperthermia and death.

15
Q

Posterior hypothalamic nuclei

A

regulate heat conversation and heat production when the body is cold.

16
Q

Standard error

A

SD/sqrt(n)

Account for variability due to sampling and helps estimate the true mean of the underlying population

17
Q

Red blood cell fragments, burr cells, and helmet cells

A

Associated with either microangiopathic hemolytic anemia or mechanical red cell destruction.

In patients with prosthetic valves, RBCs are exposed to excessive shear and turbulence in the circulation, causing damage from mechanical trauma.

18
Q

Obstructive Sleep Apnea Syndrome

A

recurrent nocturnal upper airway obstruction and apnea (daytime sleepiness, poor energy).

Each nocturnal episode of reduced ventilation causes transiet hypercapnea and hypoxemia resulting in reflexive systemic and pulmonary vasoconstriction as well as sympathetic cardiac stimuolation.

Can result in pulmonary hypertension and right heart failure.

19
Q

Left ventricular systolic failure

A

Usually due to to myocardial ischemia and causes heart failure, which decreases ejection fraction and increases end-systolic ventricular volume.

S3 sound (ventricular gallop) is audible from blood rushing into a partially filled ventricle or stiff ventricle.

S3 best heard with bell (low frequency sounds) in left lateral decubitus position with the patient exhaling to bring the heart closer to the chest wall.

20
Q

Straining phase of Valsalva manuever (bearing down against closed glottis)

A

Differentiates between causes of systolic murmur in the left heart.

Decrease venous return to the heart, reducing left ventricular volume and blood pressure.

Murmurs associated with MVP and hypertrophic cardiomyopathy become more audible.

Murmurs associated with aortic stenosis are less audible.

21
Q

Supine hypotension syndrome (Aortocaval compression syndrome)

A

Hypotension, pallor, sweating, nausea, and dizziness that occurs when a pregnant woman lies supine. Symptoms resolve when standing or left lateral decubitus position.

Due to gravid uterus compressing and obstructing IVC (reduces venous return, which lowers CO and leads to hypotension).

22
Q

Alcoholics and pulmonary infections

A

Alcoholics are at increased risk for aspiration pneumonia because alcohol intoxication impairs the gag and cough reflexes. Poor oral hygiene, impaired phagocytic and/or bactericidal action of alveolar macrophages.

Pulmonary infections usually polymicrobial: anaerboic (Bacteriodes, Prevotella, Fusobacterium, Peptostreptococcus) admixed with aerobic (Streptococcus, Klebsiella).

Clindamycin covers most of these organisms - antibiotic of choice for treating lung abscesses.

23
Q

Anemia associated with neurologic abnormalities

A

Vitamin B12 deficiency .

Hematological manifestions are megaloblastic anemia and pancytopenia.

Cofactor for methylmalonyl CoA mutase (methylmalonyl CoA into succinyl CoA). Leads to elevated methylmalonic acid which result in myelin synthesis abnormalities (subacute, combined degeneration of posterior and lateral spinal columns).

Loss of position and vibration sensation, ataxia, and spastic paresis.

24
Q

Decrease progression of diabetic nephropathy

A

ACE-I class of drug with Angiotensin receptor blockers

25
Q

tRNA regions

A

Acceptor stem - helps to mediate correct tRNA recognition by the proper aminoacyl tRNA synthetase (load correct amino acid)

3’ CCA tail - recognition sequence by proteins. recognize tRNA molecules, necessary for protein translation. hydroxyl group at the ened is binding site for the amino acid

D arm - contains dihydrouracil residues

Anticodon arm - complementary to mRNA codon (read in 3’ to 5’)

T arm - TWC sequence necessary for binding of tRNA to ribosomes. Presence of thymidine, pseudouridine, and cytidine

5’ terminal phosphate

26
Q

HbS

A

Valine (nonpolar) is in place of glutamic acid in 6th aa position of beta subunit.

Promotes hydrophobic interaction among hemoglobin molecules when no oxygen is bound and results in polymerization of HbS molecules and RBC distortion.

27
Q

HbM

A

mutation in heme binding pocket of either alpha or beta chain.

results in an iron phenolate complex that resists the reduction of iron to the ferrous state

28
Q

β-hCG

A

produced by human conceptus (blastocyst) 6 days after ovulation.

Successful implantation is required in order for there to be hCG in the maternal serum (begins day 6 and may require up to 11 days to appear)

29
Q

Primary osteoporosis

A

Osteoporosis not caused by a medical disorder

in postmenopausal osteoporosis, cancellous bone is involved (predominant in vertebral column, distal radius, hip and neck of femur)

Serum calcium phosporus, and PTH levels are typically normal.

30
Q

Pentazocine

A

Opioid narcotic with partial agonist activity and weak antagonist activity at mu receptors.

Can cause withdrawal symptoms to patients dependent on morphine due to its antagonist effects.

31
Q

Treatment of overdose on β-blcokers

A

Glucagon - increases hr and contractility independent of adrenergic receptors.

Glucagon activates GPCRs on cardiac myocytes, causing activation of adenylate cyclase and raising intracellular cAMP. This results in calcium release from intracellular stores and increased SA node firing.

32
Q

Where are β1 receptors found?

A

Cardiac tissue and renal juxtaglomerular cells.

β-blockers will decrease intracellular cAMP levels.

33
Q

Gs, Gq, Gi

A

Gs - activates adenylyl cyclase which converts ATP to cAMP. Increases in cAMP activate protein kinase A.

Gi - inhibits adenylyl cyclase and decreases cAMP.

Gq - activates phospholipase C which degrades membrane lipids into DAG and IP3. Protein kinase C is activated by DAG and Calcium is released from SR under the influence of IP3

34
Q

Proto-oncogenes (Tumor promotors)

A

Ras: bladder, lung, colon, pancreas, kidney cancers

N-myc: neuroblastoma, small cell carcinoma of the lung

ERB-B1: squamous cell carcinoma of the lung

ERB-B2: breast and ovarian cancer

TFG-a: astrocytoma, hepatocellular carcinoma

sis: astrocytoma, osteosarcoma

abl: CML, ALL

35
Q

Anti-oncogenes (Tumor suppressors)

A

BRCA-1,2 (DNA repair genes): breast and ovarian cancer

NF-1: neuroblastoma, neurofibromatous type 1, sarcomas

APC/β-catenin: gastric, colonic, and pancreatic cancer; familial adenomatous polyposis coli

DCC: colon cancer

p53: majority of cancers, Li-Fraumeni syndrome

RB: retinoblastoma, osteosarcoma, others

WT-1: Wilms tumor

36
Q

How does diptheria toxin work?

A

AB exotoxin. A subunit transfers a ribose residue from NAD to elongation factor-2 and inactivates it. This inhibits protein synthesis and causes cell death.

37
Q

How does C. perfringins exotoxin work?

A

Lecithinase is the exotoxin.

Degrades membrane phospholipids (including lecithin), leading to cell membrane destruction and cell death.

Causes gas gangrene.

38
Q

How does Bordetella pertussin toxin work?

A

AB exotoxin that stimulates G-proteins to icrease cAMP production, leading to increased insulin production, lymphocyte and neutrophil dysfunction, and increased sensitivity to histamine.

39
Q

Which bacterial toxins inactivate 60s ribosomal subunit?

A

Shigella’s shiga toxin

EHEC’s shiga-like toxin

40
Q

Transamination

A

occurs between amino acid and a-keto acid (turning the a-keto acid into an amino acid)

Pyrodixal phosphate (Vitamin B6) is a cofactor for transamination and decarboxylation.

41
Q

Cofactors for biochemical reacions

A

Thiamine (B1): transketolase, a-ketoglutarate dehydrogenase, pyruvate dehydrogenase

Riboflavin (B2): dehydrogenase rxns involving FMN and FAD

Niacin: forms NAD and NADP required for dehydrogenases

Biotin: pyruvate carboxylase, acetyl CoA carboxylase, propionyl CoA carboxylase, 3-methylcrotonyl-CoA carboxylase

Folic acid: nucleic acid synthesis

42
Q

Difference between membranous and membranoproliferative glomerulonephritis

A

Membranoproliferative glomerulonephritis: LM shows large hypercellular glomerui

Membranous: Diffudse thickening of capillary wall without an increase in cellularity, “spike and dome” and IgG and C3 deposits ane

43
Q

How does Rb protein work?

A

Regulates G1-S phase transition.

It is active when hypophosphorylated.

Inactive when hyperphosphorylated (due to proliferation signals like CDK4 - cyclin-dependent kinase-4)