Possibly some of the questions must have been answered but the explanations were not given or was a bit shaky to grasp the concept. Kindly offer the correct chioces with explanation to the below questions. Thank you in advance.
A 6-month-old boy is brought to the physician by his mother because of a
10-week history of cold-like symptoms. The mother says that he tastes
salty whens he kisses him. and he has large. foul-smelling stools. There
is no family history of a similar condition. He is at the 10th percentile
for length and 3rd percentile forweight. Physical examination shows
reduction in subcutaneous fat. Coarse rhonchi are heard
bilaterally.Molecular analysis shows deletion of the Phe residue at
position 508 in the cysticfibrosis transmembrane conductance regulator
(CFTRJ. Which of the following most likely occurred in this patient as a
result of this gene mutation?
A.Altered CFTR folding You got a mutation, therefore the translation will result in an abnormal protein (vs normal functioning one). You should also note the differences of a normal functioning CFTR in tissue VS sweat glands.
B.Beta-amyloid configuration of CFTR
C.Decreased surfactant protein synthesis
D.Increased CFTR conductance
E.Increased CFTR in the membrane (Wrong) Kindly explain the concept if
possible.
A 2-month-old boy is brought to the phvsician because of failure to thrive
and poorfeeding since birth He was recentlv adopted from Romania and has
been fed cow's milk. He is below the 5th percentile for length and weight.
Physical examination shows jaundice. cataracts. and hepatomegaly. Serum
studies show a decreased glucose concentration. The urine shows a positive
reaction to a copper reduction test and a negative reaction to a test
agent that contains glucose oxidase.Deficiency of which of the following
hepatic enzymes is the most likely cause of the disorder in this patient?
A.Fructokinase
B.Fructose-1.6-bisphosphate aldolase
C.Galactokinase
D.Galactose-1-phosphate uridyltransferase (Was this the correct answer,
unmarked due to lack of time)
E.Glucose-6-phosphatase
What does the copper reduction test and glucose oxidase positivity signify here??? Kindly explain.
Need someone to correct me here. Here's my take on it: The Failure to properly metabolize galactose results in the accumulation of toxic substances, this also causes excess free H+ . In the presence of Copper it will bind the free H+ resulting in a copper reduction.
A randomized cohort study of drug X administered to subjects after a
myocardial infarction found that overall there was no decrease in
mortality compared with administration of a placebo after a myocardial
infarction. However. on review of the data. there were statistically fewer
deaths among drug X subjects in
the subgroup with nontransmural myocardial infarction than in the placebo
group. A retrospective assessment of the database available for drug X
supported the observation. Which of the following is the most appropriate
next step?
A.Cross-sectional population study of administration of drug X vs. placebo
after nontransmural myocardial infarction
B.Prospective. randomized. controlled study of administration of drug Xvs.
placebo after nontransmural myocardial infarction
C.Treatment of all patients with drug X after myocardial infarction F
D.Treatment of only patients with nontransmural myocardial infarction with
drug X (wrong)
E.Treatment of only patients with transmural myocardial infarction with
drug X
Kindly explain the concept with the answer...!
A 32-year-old woman comes to the physician because of intermittent
abdominal cramps and diarrhea. alternating with constipation. The stools
are loose and brown: there is no blood or mucus. She has had these
symptoms for 15 years. but they have become more frequent during the past
3 months. She has not had fever orweight loss. Colonoscopy 3 years ago
showed no abnormalities. She recently was promoted to a management
position at her company. She is 160 cm (5 ft 3 in] tall and weighs 75 kg
(165 lb]: BMI is 29 kg./m2. Her temperature is 37°C (98.6°F]. pulse is
72/'min. respirations are 16/min. and blood pressure is 130/76 mm Hg.
Examination shows no abnormalities. Test of the stool for occult blood is
negative. Which of the following is the most likely diagnosis?
A.Colon cancer
B.lnflamatory bowel disease
C.lrritable bowel syndrorne When you hear diarrhea, constipation, alternating, women, and examination shows nothing wrong suspect IBS.
D.Pancreatic insufficiency (Wrong)
E.Peptic ulcer disease
No blood and mucus rules out choices B&E with A as no wt loss BMI 29/kg. That leaves us two choices Was not sure of irritable bowel syn therefore I left the choice considering blood and mucus may precipitate as the name suggest. kindly explain with the correct answers.
33. A 63-year-old man comes to the physician because of weakness and
fatigue for 8 months. Physical examination shows massive splenomegaly.
Laboratory studies show:
Hemoglobin 8.2 g/dl_
Hematocrit 25%
Leukocyte count 6000./mm? _
Platelet count 60.000/mm?
A peripheral blood smear shows the presence of myelocytes. metamyelocytes.
nucleated erythrocytes. and tear rop erythrocytes. A bone marrow specimen
shows markedly thickened trabeculae with replacement of the arrow by
cellularfibrous tissue with admixed row elements. Which of the following
is the most likely diagnosis?
A.Acute myelogenous leukemia (Wrong)
B.Aplastic anemia
C.Immune thrombocytopenic p
D.Megaloblastic anemia
E.Myelofibrosis Tear Drop cells is pathognomonic for Myelofibrosis. Think of it this way, the BM is fibrotic, when the lineage cell lines try to come out they get squeezed through these fibrotic material resulting in its tear drop shape.
I chose this answer due to leukocyte count normal not (pancytopenia)
presence of blast cells Metamyelocyte and myelocyte. How to differentiate
or discard acute myeloid leukemia not all question would mention Auer rods
in the question stem.
A 23-year-old woman at 32 weeks‘ gestation comes to the emergencv
department because of a 1 day history of flank pain and fever. Her
temperature is 39°C (102.3°F]. pulse is 104./min. respirations are 14/min.
and blood pressure is 120/72 mm Hg. Physical examination shows prominent
tenderness overthe left costovertebral angle A photomicrograph of a renal
biopsy specimen from a similar patient is shown. Which of the following is
the most likely diagnosis?
A.Acute pyelonephritis HUS you see in kids and elderly (usmleRX says elderly but its more so in kids). But the answer here is Acute Pyelo since this lady has CVA tenderness, the other choices are far-fetched.
B.Acute renal infarction
C.Acute tubulointerstitial nephritis (Was this the answer ???)
D.Crescentic glornerulonephritis (Wrong) if possible could you explain the
figure to derive the conclusion.No clue in the question stem I deem.
E.Hemolytic uremic syndrome
How to differentiate from HUS??? Explain.
During an experiment. an investigator wishes to evaluate the serum
cholesterol concentrations of all patients overthe age of 50 years on the
day of admission to the hospital. Both the mean and the median are the
same. lt is decided to use the mean as the measure of central tendency.
Which of the following is the most appropriate measure of dispersion to
analyze the data for this experiment?
A.Coefficient of variation
B.lnterquartile range
C.Percentile
D.Range (wrong)
E.Standard deviation (Was this the right answer??? if so How to
differentiate this from Coefficient of variation? Kindly explain)
2. The graph shows the response elicited by different concentrations of
drug X in a systern containing spare receptors in the absence (solid
curve] and presence {dashed curves] of two different concentrations of
drug Y. Drug Y alone has no effect. Which of the following best describes
drug Y?
A.Competitive reversible antagonist (wrong)
B.Full agonist
C.Inverse agonist
D.Noncompetitive antagonist
E.Partial agonist
Many gave D.Noncompetitive as the correct response for spare receptor...!
But whether there are spare receptors or not they act on different recptor
than the same as for a competitive antagonist and would bring the efficacy
down. How to differentiate it from a partial agonist? To me E. this seems an
attractive choice. Kindly explain the correct choice with narration of
course...
A 43-year-old woman with systemic lupus erythematosus has nephrotic
syndrome. Examination of renal tissue obtained on biopsy shows a diffuse
proliferative glomerulonephritis with electron-dense deposits along the
glomerular basement membrane. lmmunofluorescent studies show granular
deposits of complement along the basement membrane. Which of the
following is the most likely cause of these findings?
A.Antibodies directed against glomerular basement membrane (Wrong)
B.Antibodies directed against viral antigens expressed on endothelial
cells (What does this signify?)
C.Anti-DNA/DNA immune complex deposition in glomeruli (Was this the
answer????)
D.Autoantibodies to podocyte antigens
E.CD8+ T-lymphocijte cytotoxiclityzolil‘virds-infected mesangial cells
A previously healthy 71-year-old man comes to the physician because of a
1-day history of pain and swelling of his right leg. Physical examination
shows diffuse edema of the right lower extremity and calf tenderness.
Doppler ultrasonography shows a deep venous thrombosis in the right lower
extremity. After starting heparin therapy immediately. it is most
appropriate to initiate a 6-month course of a medication with which of the
following mechanisms of action?
A.Binds to the active site on the thrombin molecule (wrong)
B.lnterferes with the carboxylation of coagulation factors ( was this the
answer???) Heparin is given IV in hospital's and when this gentleman needs to leave, he is placed on long-term therapy of Warfarin.
C.lrreversibly inactivates cyclooxygenase
D.Potentiates the action of antithrornbin III
E.Selectivelv inhibits factor Xa
Kindly explain with the correct choices.
Any help will be greatly appreciated... Thank you
