pearljam59
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Hello, these are questions from the USMLE CD sent out with Prometrics. I have all the answers to these question but I would like people to contribute discussion on WHY the answers are what they are. Any input on any question would be greatly appreciated.
Block 1:
10. Platelet derived growth factor binds to its receptors, activating cell growth. The receptor-growth factor complex uses which of the following mechanisms to signal the cell to divide?!
A. Activatin of tyrosine kinase
B. Binding of GTP to a G protein
C. Binding to DNA
D. Increase in intracellular calcium concentration
E. Opening of an ion channel
17. A 60yr old woman who has had four children and completed menopause 6yrs ago develops urinary incontinence whenever she coughs, sneezes or laughs. The physician should suggest exercises to strnegthen which of the following muscles?!
A. Detrusor
B. Obturator internus
C. Piriforms
D. Rectus Abdominus
E. Urogenital diaphragm
26. Four drugs produce the same therapeutic effect by the same mechanism, but each has a unique toxicity. When used at a maximally effective therapeutic dose, the drug with which of the following sets of characteristics have the highest incidence of toxicity?!
Median effective dose---Toxic dose/eff dose
A. 0.5x----------------------2.8
B. 1x------------------------2.1
C. 5x------------------------4.0
D. 33x-----------------------3.0
27. A couple requests blood typing of their 2yr old child (father AB, Rh-negative; mother B, Rh-negative). Results of hemagglutination assays of the child's blood are as follows: (+ = hemagglutination; - = no hemagglutination)
Saline plus childs RBC -
Anti A plus childs RBC -
Anti B plus childs RBC +
Anti D plus childs RBC -
Childs serum plus type A RBC +
Childs serum plus type B RBC -
Childs serum plus type D RBC -
Which of following conclusions concerning the child's parentage is valid?!
A. The child could be the natural offspring of this couple
B. The mother could be the natural mother but the father could not be the natural father
C. The father could be the natural father but the mother could not be the natural mother
D. Neither the father nor the mother could be the natural parents
Block 2:
6. An 80yr old man has an ulcerating carcinoma of his scrotal skin on the right. Which group of lymph nodes is most likely to receive metastatic cells first?!
A. External iliac
B. Internal iliac
C. Superficial inguinal
D. Deep inguinal
E. Lumbar (para-aortic)
14. I just need someone to explain what role albumin plays when it binds to a drug?!
26. While smoking crack cocaine, a 16yr old boy develops substernal chest pain. An ECG is consistent with anterior wall myocardial ischemia. The drug most likely had which of the following effects on the heart?!
A. Direct inhibition of betaadrenergic receptors
B. Direct stimulation of adenosine receptors
C. Direct stimulation of beta adrenergic receptors
D. Indirect stimulation of alpha adrenergic receptors
E. Indirect inhibition of alpha adrenergic receptors
Block 3:
26. A 17yr old girl sustains a contaminated deep puncture wound while helping repair a barn. Her immunization record indicates that her last tetanus immunization was 12yrs ago. In addition to wound care, which of the following is th emost appropriate management?!
A. Tetanus antitoxin
B. Tetanus toxoid
C. Tetanus antitoxin plus toxoid
D. Tetanus toxoid plus adjuvant
E. No intervention
Please number the question you are responding to and once again any input on WHY the answers are as they are would be appreciated!
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| druas
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hi pearljam...can u plz tell me where these answers are availabale..thanksbn
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| pearljam59
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The answers are given out after you do each question...but there are no explanations.
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| yasmeen
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q 1- is b,q2-e its stress incontinence,q-3 d as toxic dose is less then effective,q-4is a ,q6 is c,albumin binds the drug and decrease its conc in blood while type 2 drugs like sulfonamides displace them from albumin increasing there conc in blood,q-15 is c as cocaine simply block uptake of norepinephrine which will act on beta 1 receptors on heart,q-16 is c as her last immun was more than 10 years, i hope i,m right any comments
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| pearljam59
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Anyone else?!
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| doc179
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10)A
17)E
26)B the drug which has the lowest therapeutic index has the highest toxicity
27)A as the child has anti B + and his serum and type A RBC + agglutination
26)D cocaine inhibits the reuptake of norepinephrine hence indirectly acting on alpha receptors and causes vasoconstriction..coronary vasospasm
pls let me know where I am wrong and why
Thank you
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| yasmeen
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oh no yes ur right cocaine will indirectly activate alpha recep how can i b so stupid
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| pearljam59
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Anyone else? WITH EXPLANATIONS?!
Edited by pearljam59 on 03/29/06 - 08:22 AM
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| druas
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Q6.......C
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| sosikan
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10 A
17 E
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| docarchana
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27 - we can say that the child has bl gr B. how can we say A is ans?
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| suv
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The phenotype and genotype of the father is AB negative.since the phenotype of the mother is B negative, she could be either BB or BO negative.the RH allele is recessive so 2 phenotypic RH negative individuals can produce only RH negative child.the 2 types of matings(ABXBB or ABXBO)could produce type AB or B or A children.since the child is B negative, there are no inconsistencies that the child could be the offspring of this couple.
hope this helps.
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| docarchana
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wow, thanx suv
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| docarchana
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is 26 C?
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| suv
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no its D as explained by doc 179
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| docarchana
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suv im asking about 26 in block 3 (tetanus q)
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| suv
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oops iam sorry yes its C
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| docarchana
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block 2 Q 14 (albumin) whats the ans?
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