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Flashcards in UWORLD Deck (201):
1

How do Corynebacterium acquire the ability to cause severe pseudomembranous pharyngitis?

The acquire the Tox gene (exotoxin) via lysogenization by a temperate bacteriophage (phage incorporates into bacterial chromosome)

2

a. What happens if there are no Sertoli cells during gestation?
b. What if there are no Leydig cells?

a. The Sertoli cells secrete MIF and cause mullerian ducts to involute --> without them the paramesonephric ducts develop into internal female genitalia
b. The Leydig cells secrete testosterone that stimulate formation of mesonephric ducts into internal male genitalia
(Testosterone is converted to DHT which causes formation of male external genitalia)

3

What is the NPV

The probability that a patient truly does not have a disease if she tests negative for the disease
True negatives/Total negative tests
Inversely proportional to prevalence of disease

4

Features of Edwards syndrome (Trisomy 18)

Small jaws (micrognathia)
Small eyes (microopthalmia)
Malformed, low-set ears
Rocker-bottom feet (also Trisomy 13)
Clenched hands with overlapping fingers (Distinguishing)

5

What is Heteroplasmy?

Describes the presence of normal and mutated mtDNA --> results in variable expression in mitochondrially inherited disease
-Example is MELAS
-Mitochondria inherited exclusively from maternal

6

What is route that Neisseria meningitidis causes meningitis?

Spread via respiratory and oral secretions --> pharynx --> blood --> choroid plexus --> meninges

7

Medications that can cause hyperkalemia

Nonselective beta-adrenergic blockers (interfere with Beta 2 mediated intracellular K uptake)
ACE inhibitors (inhibit Ang II formation with subsequent decrease in aldosterone secretion)
ARBs (decreasing aldosterone secretion)
K+ sparing diuretics (block ENaC or aldosterone receptor)
Cardiac glycosides (inhibit Na/K/ATPase pump)
NSAIDs (impaired local prostaglandin synthesis reduces renin and aldosterone secretion

8

Examples of stimulus control treatment for insomnia

Leave bedroom when unable to sleep
Use bed only for sleep and sexual activity
Go to bed only when sleepy
Fixed wake-up time, including weekends

9

High systolic pressure gradient between left ventricle and aorta

Left ventricular outflow obstruction
Aortic stenosis

10

a. Which artery supplies anterior and left lateral surfaces of heart?
b. What does right dominant circulation mean?
c. Which artery supplies inferior wall of left ventricle (diaphragmatic surface of heart)?

a. Left Anterior Descending and Left Circumflex Coronary artery
b. Right coronary artery gives rise to PDA (85%)
c. Posterior Descending/Interventricular Artery (PDA)

11

Which nerve is the first arch associated with?
Abnormalities include malformation of which bones?

Trigeminal nerve
Mandible, maxilla, malleus, incus, temporal bone, incus, palate

12

Which amyloid is associated with Alzheimer disease? What is it a product of?

AB amyloid
Product synthesized by cleavage of APP

13

What kind of auto-antibodies are helpful in diagnosis of RA?

Anti-citrullinated peptides

14

How might a patient receiving multiple blood transfusions develop hypocalcemia and paresthesias?

Whole blood collections contain citrate that can chelate serum calcium and cause hypocalcemia

15

How does a Prolactinoma cause impotence in males?

Prolactin suppresses GnRH --> decreased LH and decreased testosterone

16

A. Cushing syndrome with elevated ACTH levels that are suppressed by high dose but not low dose dexamethasone
B. Cushing syndrome with elevated ACTH levels that are NOT suppressed by high or low dose Dexamethasone

a. Pituitary adenoma
b. Ectopic ACTH secreting tumor

17

Argatroban

Direct Thrombin inhibitor that can be used instead of Heparin/LMWH to treat HIT

18

a. Nerve roots of Pudendal nerve
b. Provides sensory innervation to:
c. Motor innervation
d. Anatomic landmarks

a. S2-S4
b. Perineum and genitals
c. Urethrae and external anal sphincter
d. Palpate intravaginally for the ischial spine

19

What kind of receptor does insulin bind and what are the effects?

Insulin binds tyrosine kinase receptor that causes phosphorlyation and leads to a citation of protein phosphatase
-Protein phosphatase dephosphorylates glycoen synthase --> activating it and promoting glycogen synthesis
-Protein phosphatase dephosphorylates fructose 1,6 bisphosphatase --> inactivating it and inhibiting gluconeogenesis

20

What kind of receptor does insulin bind and what are the effects?

Insulin binds tyrosine kinase receptor that causes phosphorlyation and leads to a citation of protein phosphatase
-Protein phosphatase dephosphorylates glycogen synthase --> activating it and promoting glycogen synthesis
-Protein phosphatase dephosphorylates fructose 1,6 bisphosphatase --> inactivating it and inhibiting gluconeogenesis

21

How can Strep pneumo obtain genetic material to make it virulent?

Transformation - direct uptake of naked DNA from environment
Through this mechanism, nonvirulent, non-capsule strains of S. pneumo can acquire genes that code the capsule and gain virulence

22

What is a koilocyte?

Sign of infection with HPV; an immature squamous cell with dense, irregularly staining cytoplasm and perinuclear clearing resulting in a halo

23

What are Clue cells?

Seen in Pap smear specimens from women with bacterial vaginosis (Gardnerella vaginalis); they are squamous cells covered with bacilli

24

a. Gram negative oxidase-positive, non-lactose fermenting motile rods that produce pigment
b. What disease does it cause?

a. Pseudomonas
b. Hot tub folliculitis - diffuse pruritic papulopustular rash

25

a. Anti-apoptotic proteins
b. Pro-apoptotic proteins
c. Released from mitochondria during apoptosis

a. Bcl-2, Bcl-x
b. Bak, Bax, Bim
c. Cytochrome C --> activate caspases

26

a. What kind of drugs lead to increased lithium levels?
b. What are signs of lithium toxicity?

a. Thiazide diuretics, ACE inhibitors, NSAIDs (lithium is excreted almost exclusively by the kidneys - filtration and resorption in the proximal tubule follows sodium reabsorption)
b. Tremors, agitation, ataxia, delirium, neuromuscular excitability

27

What drugs are used in asthma provocation test?

Methacholine - muscarinic cholienrgic agonist that causes bronchoconstriction and increased airway secretions
Histamine
Exercise
Cold air inhalation

28

What is Isoproterenol?

Nonspecific beta-adrenergic agonist that causes bronchodilation

29

What is Scopolamine?

Antagonist of muscarinic cholinergic receptors used for motion sickness

30

Prophylaxis of Mycobacterium Avium Complex

Azithromycin

31

Pharmacologic treatment of Restless Leg Syndrome

Dopamine agonist - Pramiprexole

32

S/E of Colchicine

Diarrhea
N/V
Abdominal pain
(disrupts microtubule formation in GI mucosal cells)

33

What is seen on small intestine biopsy of Celiac disease patient?

Flattening of mucosa with loss of villi and chronic inflammatory infiltration of the lamina propria

34

a. Three main causes of HIV-associated esophagitis
b. Endoscopic findings in each

a. Candida, CMV, Herpes
b. Candida - patches of adherent, gray/white pseudomembranes, Herpes - Small vesicles that evolve into typical punched out ulcers, CMV - linear ulceration

35

How is Isoniazid metabolized?

By acetylation

36

How are Azathioprine and 6-mercaptopurine metabolized?

Methylation

37

Important allosteric activator of gluconeogenesis that acts by increasing the activity of pyruvate carboxylase

Acetyl-CoA

38

a. What kind of collagen is found in mature scars?
b. What else does this collagen form?

a. Type I collagen
b. Bone, tendon, dermis, ligament, dentin, cornea, blood vessels

39

a. Echocardiogram of aorta lying to the right and anterior of the pulmonary artery
b. Caused by?

a. Transposition of the great arteries
b. failure of the fetal aorticopulmonary septum to spiral normally during septation of the truncus arteriosus

40

a. Vitamin B1?
b. Associated with?

a. Thiamine
b. Dry beriberi (symmetrical peripheral neuropathy with sensory/motor impairments of distal extremities), wet beriberi (neuropathy + dilated cardiomyopathy, CHF, peripheral edema), Wernicke-Korsakoff syndrome

41

Majority of Down's syndrome cases occur due to:

Maternal meiotic non-disjunction
-Robertsonian translocations account for 3-4% (t14:21 or t21;22)

42

Why does administration of glucose to alcoholics cause Wernicke encephalopathy (confusion, ataxia, opthalmoplegia)?

Many alcoholics are deficient in thiamine and thiamine is necessary for the TCA cycle because it is a cofactor of alpha keto glutarate dehydrogenase

43

Why does administration of glucose to alcoholics cause Wernicke encephalopathy (confusion, ataxia, opthalmoplegia)?

Many alcoholics are deficient in thiamine and thiamine is necessary for the TCA cycle because it is a cofactor of alpha keto glutarate dehydrogenase

44

What are effects of Sotalol on heart?

It blocks beta adrenergic receptors and K channel receptors to cause bradycardia (prolonged PR interval) and prolonged QT interval

45

What are effects of Sotalol on heart?

It blocks beta adrenergic receptors and K channel receptors to cause bradycardia (prolonged PR interval) and prolonged QT interval

46

Complicates asthma and results in recurrent pulmonary infiltrates, eosinophilia and proximal bronchiectasis

Asperillus fumigatus - causes Allergic bronchopulmonary aspergillosis

47

Complicates asthma and results in recurrent pulmonary infiltrates, eosinophilia and proximal bronchiectasis

Asperillus fumigatus - causes Allergic bronchopulmonary aspergillosis (also associated with CF)

48

Complicates asthma and results in recurrent pulmonary infiltrates, eosinophilia and proximal bronchiectasis

Asperillus fumigatus - causes Allergic bronchopulmonary aspergillosis (also associated with CF)

49

Lymph from the testes drains to...
Lymph from the scrotum drains to...

-para-aortic nodes
-superficial inguinal nodes

50

Lymph from the testes drains to...
Lymph from the scrotum drains to...

-para-aortic nodes
-superficial inguinal nodes

51

In the true pelvis, the left ureter is anterolateral to which structure?

Internal iliac artery

52

In the true pelvis, the left ureter is anterolateral to which structure?

Internal iliac artery

53

What allows for binding of myosin to actin?

Upon release from SR, Calcium binds Troponin C on thin filaments. This causes conformational change and tropomyosin shifts so the myosin binding sites on actin are exposed.

54

What allows for binding of myosin to actin?

Upon release from SR, Calcium binds Troponin C on thin filaments. This causes conformational change and tropomyosin shifts so the myosin binding sites on actin are exposed.

55

Gram negative, oxidase positive rod that grows well on alkaline media

Vibrio cholerae

56

Gram negative, oxidase positive rod that grows well on alkaline media

Vibrio cholerae

57

Why is Ceftriaxone not successful in treating Chlamydia infections?

They have a cell wall but it does not have peptidoglycan.

58

Why is Ceftriaxone not successful in treating Chlamydia infections?

They have a cell wall but it does not have peptidoglycan.

59

Little boy losing motor skills, hepatosplenomegaly, cherry red spot on macula, sphingomyelin accumulated in leukocytes

Niemann Pick Disease

60

Little boy losing motor skills, hepatosplenomegaly, cherry red spot on macula, sphingomyelin accumulated in leukocytes

Niemann Pick Disease

61

GM2 ganglioside accumulation

Tay Sachs
Deficiency of Hexoaminidase A

62

GM2 ganglioside accumulation

Tay Sachs
Deficiency of Hexoaminidase A

63

How does Hartnup disease cause Pellagra?

The intestinal and renal absorption of Tryptophan is defective --> Tryptophan is necessary for Niacin

64

How does Hartnup disease cause Pellagra?

The intestinal and renal absorption of Tryptophan is defective --> Tryptophan is necessary for Niacin

65

What kind of blood cell can increase after administration of glucocorticoids?

Neutrophils; as a result of demargination of leukocytes previously attached to vascular wall

66

What kind of blood cell can increase after administration of glucocorticoids?

Neutrophils; as a result of demargination of leukocytes previously attached to vessel wall

67

What kind of blood cell can increase after administration of glucocorticoids?

Neutrophils; as a result of demargination of leukocytes previously attached to vessel wall

68

What is the mechanism of Acarbose?

Alpha-glucosidase inhibitor that decreases the activity of disaccharidases on the intestinal brush border; disaccharidases are membrane bound enzymes

69

What is the mechanism of Acarbose?

Alpha-glucosidase inhibitor that decreases the activity of disaccharidases on the intestinal brush border; disaccharidases are membrane bound enzymes --> inhibits carbohydrate absorption because carbohydrates are absorbed as monosaccharides

70

What is the mechanism of Acarbose?

Alpha-glucosidase inhibitor that decreases the activity of disaccharidases on the intestinal brush border; disaccharidases are membrane bound enzymes --> inhibits carbohydrate absorption because carbohydrates are absorbed as monosaccharides

71

What does positive VDRL of the spinal fluid indicate?

Neurosyphilis

72

What does positive VDRL of the spinal fluid indicate?

Neurosyphilis (causes damage to dorsal roots and dorsal columns)

73

Cause of Xanthomas in familial hypercholesterolemia

Decreased LDL receptors

74

Difference in murmurs caused by infective endocarditis vs. rheumatic fever

Rheumatic fever - can cause mitral stenosis - low pitched mid diastolic murmur (or mitral regurgitation)
Infective endocarditis - causes mitral or tricuspid regurgitation (holosystolic murmur)

75

Pigmented mucocutaneous macules and multiple GI hamartomas

Peutz-Jeghers syndrome
Autosomal dominant; increased risk of many cancers

76

Pathogenesis of Pemphigus Vulgaris
Symptoms

IgG antibodies against Desmoglein 1 and 3 that make up desmosomes that adhere epithelial keratinocytes together
Painful flaccid bullae that appear in oropharynx, trunk and extremities

77

What do cervical spinal cord lesions cause?

Pain, distal sensory dysthesias and muscular weakness (respiratory insufficiency, difficulty swallowing)
-Ocular dysfunction is NOT typically present

78

How can a woman with Turner syndrome become pregnant?

In vitro fertilization
Most women have ovarian failure

79

Diagnosis of Diabetes Insipidus

Polyuria
Polydipsia
Urine specific gravity 290mOsm/kg

80

Polyuria and polydipsia in a Psych patient

Could be Nephrogenic DI from Lithium treatment (impairs vasopressin stimulated collecting duct water reabsorption and renal concentrating ability)

81

Cause of painless hematochezia in 2 year old

Ectopic mucosa - Meckel's diverticulum

82

How does the murmur in hypertrophic cardiomyopathy change with preload and afterload?

Increases with decreased preload or afterload
Decreases with increased preload (standing) or afterload

83

Which polymerase is responsible for removing RNA primers and synthesized DNA in it's place?

DNA Polymerase I

84

Tumor marker for ovarian cancer

CA-125

85

Immunosuppressive agent used to prevent transplant rejection that causes nephrotoxicity

Cyclosporine (dose and duration dependent rise in serum BUN and creatinine and BP)

86

Classic adverse effects of Prednisone

Avascular necrosis of femoral head
Osteoporosis
Increased serum glucose
Psych disturbances
Insomnia

87

Parkinson's patient with vomiting and gastric stasis; which medication is C/I?

Metoclopramide; can cause Parkinsonian symptoms and extrapyramidal effects due to antagonism of Dopamine receptors

88

Deficiency in alkaptonuria
Long term consequence/complications?

Cause by homogentisate oxidase deficiency that degrades phenylalanine and tyrosine --> to fumarate
Destructive arthritis later in life due to homogentisic acid accumulating in articular cartilage

89

How does acute ischemia cause changes in extracellular and intracellular ions?

Ischemia decreases ATP so that the Na/K ATPase can't function --> causes Na to leak into the cell and K leaks out
-Calcium leaks INTO cells, decreases extracellularly

90

What is the shake test?

Amniotic fluid is added to ethanol and shaken --> the foam stability index is the highest value well that contains a stable ring of foam. Considered a predictor of lung maturity in fetus.

91

Homocystinuria with Cystathionine synthase deficiency; which products accumulate and which decrease?

Methionine and Homocysteine increase
Cysteine decreases and becomes essential amino acid

92

Cause of pancreatic pseudocyst

Severe acute pancreatitis
-Normally in body or tail

93

Why is Heparin safe in pregnancy and Warfarin is not?

Heparin does not cross the placenta because it is water soluble whereas Warfarin crosses the placenta because it is lipophilic

94

Mechanism of treatment for CMV retinitis

Ganciclovir --> inhibits DNA chain elongation by incorporating into viral DNA and inhibiting viral DNA polymerase

95

Defect in glycogen phosphorylase causes impairment of what?

McArdle disease --> impairment of glycogenolysis in muscle (myophosphorylase)
Glycogenolysis is intact in liver so hypoglycemia is not a feature

96

Pathophysiology of Graves opthalmopathy?

Lymphocytes infiltrate orbital tissues and secrete cytokines that stimulate fibroblasts to secrete glycosaminoglycans like hyaluronic acid --> attract water and cause periorbital edema

97

Cause of Parinaud syndrome
Symptoms

Tumor in pineal gland (lesion dorsal midbrain in area of superior colliculus)
Cause upward gaze palsy, absent pupillary light reflex, failure of convergence and wide based gait (from damage to oculomotor and trochlear nerves and Edinger Westphal nucleus (parasympathetic))

98

Where do gastrointestinal stem cells reside?

Crypts of Lieberkuhn

99

Cause of gait ataxia, truncal instability, intention tremor and rhythmic Parkinson tremor of hands

Chronic alcoholism --> atrophy of anterior lobes and cerebellar vermis

100

Which sympathomimetic causes increased peripheral vascular resistance, increased systolic BP, decreased pulse pressure and decreased HR

Phenylephrine (a1 > a2 agonist)

101

Effects of Dobutamine

Mainly a B1 > B2 agonist ---> causes increased HR and contractility with little effect on peripheral vascular resistance

102

What is the function of TATA and CAAT boxes in eukaryotic cells?

Promoters of transcription (binding sites for RNA polymerase II)

103

a. Cause of cleft lip
b. Cause of cleft palate

a. Maxillary prominences fail to properly fuse with the intermaxillary segment
b. The palatine shelves of the maxillary prominence fail to fuse with one another or with the primary palate

104

Intracellular consequence of nitrate administration in target tissues

1. increased cGMP
2. decreased calcium
3. myosin dephosphorylation

105

Coenzymes required for Pyruvate Dehydrogenase
What happens if they are missing?

Thiamine
Lipoic acid
Coenzyme A
FAD
NAD+
-If they are missing PDH can't convert Pyruvate to acetyl coA for metabolism in TCA cycle --> this will cause pyruvate to be converted to lactate --> lactic acidosis
-Also required for ketoglutarate DH and branched-chain ketoacid DH (deficiency results in maple syrup urine disease)

106

Where does positive and negative selection of T cells occur?

Positive selection in thymic cortex
Negative selection in thymic medulla

107

Von Hippel Lindau gene mutation

Deletion of VHL gene on chromosome 3p

108

What do you expect on visual field examination with macular lesion?

Impaired central vision and central scotomata (scotoma means visual defect surrounded by relatively unimpaired field of vision)

109

Number needed to harm

1/AR
AR = (A/A+B) - (C/C+D)

110

Number needed to treat

1/ARR
ARR = (C/C+D) - (A/A+B)

111

Paraneoplastic syndrome of neuroblastoma

Opsoclonus-myoclonus = non-rhythmic conjugate eye movements associated with myoclonus

112

What is lansoprazole?

Proton pump inhibitor

113

Symptoms of acute intermittent porphyria attack?
How do you treat?

-Abdominal pain, vomiting, peripheral neuropathy, neuropsych symptoms, reddish brown urine
-Treated with glucose (dextrose) or heme which down regulate ALA synthase. Alcohol, tobacco and CYP450 inducers make it worse.

114

Cause agglutination of RBCs when a sample is placed on ice; uncoagulates when it is warmed

COLD AGGLUTININS
Mycoplasma pneumoniae, EBV and hematologic malignancies

115

How does Parvovirus attach to host cells?

Attaches to human erythroid cells via blood group P antigen (globoside).

116

How does EBV attach to host cells?

EBV envelope glycorotein gp350 binds cellular receptor CR2 or CD21

117

How do lipid lowering agents affect triglyceride levels?

1. Statins decreased TGs
2. Bile acid resins (Cholestyramine) INCREASE TGs
3. Ezetimibe has no effect on TGs
4. Fibrates DECREASE TGs significantly
5. Niacin decreases TG slightly

118

Erosions extend into which structures?

ONLY the mucosa
Mucosa includes epithelium, lamina propria AND muscularis mucosa

119

How is aseptic meningitis transmitted?

Fecal oral
Enterovirus is the most common cause of Aseptic meningitis (90% of cases)
Enteroviruses include Coxsackievirus, Poliovirus and echoviruses (naked ss linear RNA viruses = Picornavirus)

120

HDL and cardiovascular risk

Low HDL concentration is associated with increased cardiovascular risk but raising HDL levels does NOT improve cardiovascular outcomes

121

What would endometrial biopsy show in ectopic pregnancy?

The hormone changes are the same as normal pregnancy so there would be decidualization of endometrial stroma WITHOUT embryonic tissue or chorionic villi

122

Telangiectasias in oral and nasal mucosa, face, arms
Recurrent epistaxis

Osler-Weber-Rendu syndrome
(Autosomal Dominant)

123

What is condyloma lata?
What is condylomata acuminata?

Condyloma lata is wart like genital lesion that occurs during secondary syphilis
Condylomata acuminate are anogenital warts caused by HPV

124

Which cancers are associated with Rb tumor suppressor?

Retinoblastoma and Osteosarcoma

125

Who has an increased risk of developing ALL?

Patients with down syndrome, ataxia telangictasia and neurofibromatosis type 1

126

Galactose in urine and bilateral cataracts
Which enzyme is deficient? What is the disorder?

Galactokinase is deficient; Galactokinase deficiency is the disorder
-The excess galactose gets converted to galctitol by aldose reductase that accumulates in the lens

127

Drug of abuse most likely to cause violent behavior

PCP

128

Most common cause of death with PCP intoxication

Trauma

129

Motile oxidase positive gram negative rod that causes malignant otitis externa

Pseudomonas

130

Which substance has the fastest rate of metabolism in the glycolytic pathway?

Fructose; it is phosphorylated in the liver to F1P and bypasses the PFK rate limiting enzyme of glycolysis

131

What can help to identify the cause of metabolic alkalosis?

Assessing the volume status and measuring urine chloride concentration

132

What kind of neuromuscular blocking drug is Succinylcholine?

Depolarizing - in phase 1 there is no antidote but in phase II antidote is Achesterase inhibitors

133

How do you prevent deep vein thrombosis in inpatient settings/before surgery?

Unfractionated and low molecular weight heparins

134

Rare complication of left atrial enlargement?

Impingement of left recurrent laryngeal nerve --> causes hoarseness and left vocal cord paresis

135

Adenoma to Carcinoma sequence

1. Progression from normal mucosa to small polyp (APC tumor suppressor gene)
2. Increase in size of polyps (Mutation in K-Ras oncogene that causes cell proliferation)
3. Malignant transformation from adenoma to carcinoma requires mutation of p53 and DCC

136

a. Holosystolic murmurs
b. Holosystolic murmur that increases on inspiration

a. tricuspid regurgitation, mitral regurgitation, ventricular septal defect
b. Tricuspid regurgitation

137

What is heavily methylated DNA at the periphery of the nucleus?

Barr body - heterochromatin that consists of heavily methylated DNA and deacetylated histones that cause it to have low transcriptional activity

138

Cerebellar ataxia, telangiectasia and increased risk of sinopulmonary infections

Ataxia Telangiectasia (mutation of ATM gene responsible for DNA break repair) --> DNA is hypersensitive to DNA radiation

139

Generalized chromosomal instability; increased susceptibility to neoplasms

Bloom syndrome (deficient DNA repair enzyme)

140

Defect in DNA mismatch repair enzymes

Hereditary Nonpolyposis Colorectal cancer

141

Which enzymes carry out non oxidative reactions of HMP shunt?

Transketolase and transaldolase

142

Major virulence factor for Strep pyogenes

Protein M - it inhibits phagocytosis and complement activation, mediates adherence and is the target of type specific humoral immunity to S. pyogenes

143

Which nerve fibers does oculomotor nerve carry?

Purely motor carrying general visceral efferent parasympathetic fibers (GVE) and general somatic efferent fibers

144

Why do calf muscles look big in patients with Duchenne muscular dystrophy?

There is calf PSEUDOhypertrophy caused by fibrofatty replacement of muscle

145

Antibodies against polyribitol ribose phosphate protect against what?

H influenzae - capsule is made of polyribitol ribose phosphate

146

Capsule of D-glutamate

Bacillus anthracis

147

Before alanine can be converted to glucose its amino group is transferred to what?

Alpha ketoglutarate (forms glutamate)

148

Monozygotic twinning possibilities depending on when division happens

-Dichorionic/diamnionic (days 0-4)
-Monochorionic/diamnionic (days 4-8)
-Monochorionic/monoamnionic (days 8-12)
-Monochorionic/monoamnionic conjoined (past day 13)

149

How many chorions and amnions in dizygotic twins?

ALWAYS dichorionic/diamnionic

150

Why does Hepatitis D virus require confection or prior infection of Hepatitis B?

It must be coated by external coat antigen HBsAg of Hepatitis B virus in order to replicate

151

Damage to hypothalamus causes increase in which hormone?

Prolactin (normally inhibited by Dopamine)

152

Fungal infection cause hypo pigmented or hyper pigmented skin lesions. Where is it localized? How is it diagnosed?

Malasezzia furfur (pityriasis versicolor)
Localized in stratum corneum
Diagnosed by KOH treatment of skin scrapings

153

Glucocorticoid effect on protein synthesis

Inhibits protein synthesis in skeletal muscle and most tissues
Stimulates hepatic RNA and protein synthesis (specifically enzymes for gluconeogenesis and glycogenesis)

154

Important antipsychotic S/E

-Extrapyramidal (Akathisia is subjective restlessness and inability to sit still; Acute dystonic reaction is sudden onset sustained muscle contraction; Drug induced parkinsonism)
-Tardive dyskinesia: involuntary movements after chronic use
-Neuroleptic malignant syndrome: fever, rigidity, mental status changes, autonomic instability

155

Cystic tumor in cerebellum of child with Rosenthal fibers

Pilocytic astrocytoma

156

Treatment for patient with PCOS

If they want to become fertile -> need treatment for inducing ovulation --> Clomiphene is selective estrogen receptor modulator that prevents negative feedback inhibition of hypothalamuc by circulating estrogen which results in increase in FSH and LH and ovulation

157

Well defined coin lesion with popcorn calcifications

Lung hamartoma (excessive growth of tissue type native to organ of involvement) (often have hyaline cartilage)

158

What is superior mesenteric artery syndrome?

The transverse portion of the duodenum becomes entrapped by the SMA and aorta causing intestinal obstruction

159

What is a cystic hygroma?
Which disorders are they associated with?

Soft, compressible masses that transilluminate - found in head and neck (typically on left side)
Associated with Turners, Trisomy 13, 18 and 21

160

How does decreasing intracellular Na change the action potential?
Decreased extracellular Na?
Decreased intracellular K?
Decreased extracellular K?

-Increases the peak transmembrane voltage of action potential
-Decreased extracellular NA decreases the peak voltage of AP
-Decreased intracellular K = increased likelihood of AP
-Decreased extracellular K = hyper polarize neuron

161

With external radiation to the head and neck as a child, the patient has the highest risk of developing which malignancy?

Thyroid cancer

162

What part of the urea cycle is the urea exit point?

Hydrolysis of arginine allows for release of urea
Arginine + H2O --> Ornithine (release urea)

163

Cause of tardive dyskinesia

From long term anti-psychotic use; result of up regulating central dopamine receptors and decrease in cholinergic activity in striatum (antipsychotics antagonize dopamine receptors)

164

Deficiency of dopamine hydroxylase results in what?

Orthostatic hypotension (defect in sympathetic nervous system actions)
No effect on dopamine because it synthesizes NE from dopamine.

165

Improper use of crutches and mid shaft fractures of humerus damage which nerve?

Radial nerve
Impaired elbow extension - weakness for arm and forearm extensors

166

Painful pharyngeal muscle spasms, hydrophobia, ascending paralysis

Rabies infection (Negri bodies = eosinophilic inclusions)
Inactivated vaccine

167

Non polar hydrophobic amino acids

Glycine, alanine, valine, leucine, isoleucine, phenylalanine, methionine, tryptophan, proline

168

One of the first signs of cavernous sinus thrombosis

Lateral gaze palsy

169

Lumbar lordosis caused by excessive contraction of which muscles?

Hip flexors

170

Fetal anuria, oligohydramnios, limb contractures, growth retardation, calvarium defects

ACE inhibitor fetopathy (abnormal renal development)

171

Where is Apo B 100 synthesized?
Where is Apo B 48 synthesized?

Apo B 100 - in the liver
Apo B 48 - in the intestinal enterocytes; incorporated into chylomicrons

172

Inheritance of G6PD deficiency
Inheritance of hereditary spherocytosis

X linked recessive
Autosomal Dominant

173

Treatment for Tic Douloureoux (Trigeminal Neuralgia)

Carbamazepine

174

Defect in alpha ketoacid dehydrogenase

Maple Syrup Urine disease = inability to degrade branched chain amino acids = dystonia, poor feeding, sweet smelling urine
Leucine, Isoleucine, Valine

175

Oral thrush, pneumonia and severe lymphopenia in baby

Vertical transmission of HIV from mother
Give Zidovudine prenatally

176

Most common cause of multiple ring enhancing lesions in HIV patient
Treatment?

Toxoplasmosis
Pyrimethamine and Sulfadiazine

177

Second most common cause of ring enhancing lesions in HIV patient

Primary CNS Lymphoma (normally B cell)

178

Weight gain, dry skin, hair loss, constipation

LITHIUM side effects cause HYPOTHYROIDISM

179

How does carbon tetrachloride cause fatty change and liver necrosis?

Free radical injury

180

Cause of Chediak Higashi syndrome

Autosomal recessive disorder of neutrophil phagosome lysosome fusion that results in neurologic abnormalities, partial albinism and immunodeficiency

181

Portal HTN, splenomegaly, varicosities at portocaval anastomoses - NO histologic changes to liver

Portal vein thrombosis

182

Which tissue are prolactinomas derived from?

Come from lactotroph cells in anterior pituitary that is derived from surface ectoderm

183

How do nitrites cause poisoning?

They oxidize the heme iron to the ferric state; partial pressure of O2 in blood is unchanged

184

What are the most prominent bugs isolated from intra-abdominal infections?

Bacteroides fragilis and E. coli

185

Can naked influenza virus be infectious if it is introduced into a host cell?

No - for a purified RNA molecule to be able to induce viral protein synthesis in a host cell, it must be able to act directly as mRNA using the host machinery for translation. Therefore purified single strand POSITIVE sense RNA can be infectious while negative sense and ds RNA cannot. (They need RNA dependent RNA polymerase)

186

What is the most notable S/E of Ethambutol?

Optic neuritis causing color blindness, central scotoma and decreased visual acuity

187

What kind of antibiotic is Streptomycin? How do bacteria develop resistance?

Aminoglycoside; altered structure of bacterial ribosomal proteins

188

What is the mechanism of mycobacterial resistance to Isoniazid?

Decreased activity of bacterial catalase peroxidase (it is required to conversion of isoniazid to active metabolite)

189

Catalase negative, coagulase negative, PYR positive

Strep pyogenes

190

What markers are of greatest prognostic significance in cirrhosis?

Serum albumin levels, prothrombin time and bilirubin levels

191

What happens to heart with normal aging?

Decreased left ventricle size that causes ventricular septum to develop sigmoid shape
Atrophy of myocardium causes increased interstitial CT
Cardiomyocytes accumulate lipofuscin pigment

192

In elderly patient with calcific aortic stenosis, what precedes the damage?

Necrosis (or injury)
Dystrophic calcification is calcium deposition in abnormal tissues that tends to be localized- normocalcemic

193

What tumor is associated with exposure to arsenic, vinyl chloride and thorotrast? What cell marker is present?

Liver angiosarcoma - tumor of endothelial origin
CD31 marker = PECAM

194

What regulates release of insulin in pancreatic beta cells?

Glucose enters Beta cells (GLUT2) and causes glycolysis that generates ATP --> Increase in ATP/ADP ratio results in ATP binding ATP sensitive K channel --> K channel closes --> cell membrane depolarizes and Calcium channels open --> Ca influx --> stimulation of insulin exocytosis

195

Difference between Fidaxomicin and Vancomycin against C diff.

Both are oral and have minimal systemic absorption but Fidaxomicin is bacteriocidal and Vancomycin is bacteriostatic

196

What are functions of Vitamin A?

Antioxidant
Constituent of visual pigments
Essential for normal differentiation of epithelial cells into specialized tissues (pancreatic cells and mucus secreting cells)
Prevents SQUAMOUS METAPLASIA
Used to treat measles and AML subtype M3

197

What cancer is BRAF mutation associated with?

Melanoma

198

Vitamin E changes in neurologic system

Degeneration of spinocerebellar tracts, dorsal column and peripheral nerves - may mimic Friedreich ataxia

199

Which anti-inflammatory agent does not impair platelet aggregation?

Celecoxib

200

What do Auer rods stain with?

Peroxidase

201

When is isolated systolic hypertension common? What causes this?

Elderly - over 50
Caused by age related decreases compliance (stiffening) of aorta