UWORLD Flashcards
(201 cards)
1
Q
How do Corynebacterium acquire the ability to cause severe pseudomembranous pharyngitis?
A
The acquire the Tox gene (exotoxin) via lysogenization by a temperate bacteriophage (phage incorporates into bacterial chromosome)
2
Q
a. What happens if there are no Sertoli cells during gestation?
b. What if there are no Leydig cells?
A
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
Q
What is the NPV
A
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
Q
Features of Edwards syndrome (Trisomy 18)
A
Small jaws (micrognathia) Small eyes (microopthalmia) Malformed, low-set ears Rocker-bottom feet (also Trisomy 13) Clenched hands with overlapping fingers (Distinguishing)
5
Q
What is Heteroplasmy?
A
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
Q
What is route that Neisseria meningitidis causes meningitis?
A
Spread via respiratory and oral secretions –> pharynx –> blood –> choroid plexus –> meninges
7
Q
Medications that can cause hyperkalemia
A
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
Q
Examples of stimulus control treatment for insomnia
A
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
Q
High systolic pressure gradient between left ventricle and aorta
A
Left ventricular outflow obstruction
Aortic stenosis
10
Q
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
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
Q
Which nerve is the first arch associated with?
Abnormalities include malformation of which bones?
A
Trigeminal nerve
Mandible, maxilla, malleus, incus, temporal bone, incus, palate
12
Q
Which amyloid is associated with Alzheimer disease? What is it a product of?
A
AB amyloid
Product synthesized by cleavage of APP
13
Q
What kind of auto-antibodies are helpful in diagnosis of RA?
A
Anti-citrullinated peptides
14
Q
How might a patient receiving multiple blood transfusions develop hypocalcemia and paresthesias?
A
Whole blood collections contain citrate that can chelate serum calcium and cause hypocalcemia
15
Q
How does a Prolactinoma cause impotence in males?
A
Prolactin suppresses GnRH –> decreased LH and decreased testosterone
16
Q
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
a. Pituitary adenoma
b. Ectopic ACTH secreting tumor
17
Q
Argatroban
A
Direct Thrombin inhibitor that can be used instead of Heparin/LMWH to treat HIT
18
Q
a. Nerve roots of Pudendal nerve
b. Provides sensory innervation to:
c. Motor innervation
d. Anatomic landmarks
A
a. S2-S4
b. Perineum and genitals
c. Urethrae and external anal sphincter
d. Palpate intravaginally for the ischial spine
19
Q
What kind of receptor does insulin bind and what are the effects?
A
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
Q
What kind of receptor does insulin bind and what are the effects?
A
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
Q
How can Strep pneumo obtain genetic material to make it virulent?
A
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
Q
What is a koilocyte?
A
Sign of infection with HPV; an immature squamous cell with dense, irregularly staining cytoplasm and perinuclear clearing resulting in a halo
23
Q
What are Clue cells?
A
Seen in Pap smear specimens from women with bacterial vaginosis (Gardnerella vaginalis); they are squamous cells covered with bacilli
24
Q
a. Gram negative oxidase-positive, non-lactose fermenting motile rods that produce pigment
b. What disease does it cause?
A
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
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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
