nbme 11 please all help me with these answers !!!! - k2011

[ArchivalUser]

1) a 20 yr old man comes o the physcian because of a 1yr history of progressive numbness in his arms.he recently burned his rt thumbwhile cooking but felt no pain.sensation to pain and temp are reduced in bth upper extremeties and across shoulders to neck.sensation is intact elsewhere.most likely cause of the conditionis is a lesion in which one of the following spinal cord structures
A ANTERIOR WHITE COMMISSURE
B DORSAL COLUMN
C INTERMEDIOLATERALCELL COLUMN
D LATERAL CORTICOSPINAL TRACT
E SPINOTHALAMIC TRACT wrong
E is wrong, please explain with answer why


2) during a study a healthy 35 yr old woman and a 35 yr old woman with crohns are given an oral solution with radioactively labelled lactulose. th appearance of radioactivity in the urine is monitored over 24 hrs. urinary excretion of radioactivity with the patient with crohns is much greater than healthy subject, the finding is ost likley due to the inflammation assoc changes in the integrity of which of the following epithelial structures ?

A ADHERENS JUNCTION
B BASEMENT MEMBRANE
C DESMOSOMES
D GAP JUNCTIONS wrong
E TIGHT JUNCTIONS

D IS WRONG. PL explain

3) during a study to see response of renal tubular cells to ischaemic injury blood supply to the kidneys in animals is interrupted for variable lengths of time. renal tubular cells examined under light microscopy.the presence of which of the follwoing features would indicate IRREVERSIBLE injury
A BLUNTING OF MICROVILLI
B CELLULAR SWELLING wrong
C DISAGGREGATION OF RIBOSOMES
D DISRUPTION OF PLASMA MEMBRANE
E LOOSENING OF INTRACELLULAR ATTACHMENTS
b is wrong.

4) in an epidemiol study of workers in the aniline dye industry, 500 workers with bladder cancer and200 workers without baldder cancer are selected .the investig obtain a history of exposure to aniline dyes in the groups. among workers with bladder cancer, 250 have an exposure to aniline dyes and among the 200 without bladder cancer, 50 have a history of exposure . which of the following is the odds ratio for the v exposure variable?
A 0.33
B 0.5
C 1.0
D 1.5
E 2.0A wrong
F 3.0

E IS wrong and cant figure out why. please explain with answer.

5) During an expt the US11 gene product of CMV IS EXPRESSED constitutively after stable transfection in an experimental tumour cell line. it is found that this gene product causes translocation of nascent MHC class 1 molecules from the endoplamic reticulum into the cytosol.which of following is most likely to occur regarding the MHC class 1 ?
A association with invariant chain
B BINDING OF PEPTIDES from endocytic pathway - WRONG
C degradtion by proteasome
D FORMATION OF Mhc class 1/mhc class 2 hybrid mols
E INTERACTION WITH t lymphocyte receptor

pl explain. was conviced it should be BBB


thanks
appreciate your help asap. need answers asap as exam v soon

[ArchivalUser]

qx number 4 , answer is F) 3

explanation,: OR = odds of having disease in exposed group divided by odds of having disease in unexposed group. 250 x 150
__________ = 3
50 x 250

[ArchivalUser]

i still come out with E for that question -stats no 5 please explain further
can anyone answer others please wih explanation
thanks

[ArchivalUser]

E is wrong , explain how you came out with E

[ArchivalUser]

ok here is why i came out with E

odds disease in exposed gp = 250/500
odds disease in unexposed gp =50/250
so 250/500 divided ny 50/250 = 222
therfore E
SO HOW DO YOU or anyone get FFF

PLEASE EXPLAIN, DONT UNDERSTAND WHY YOU ARE MULTIPLYING 250 WITH 150 AND 50 BY 250.

PLEASE EXPLAIN.. marc 923 or anyone..

[ArchivalUser]

qno1-i did the same mistake. I think if spinothalmic tract leison u see unilateral signs. here bilateral. so it is due to anterio commisure leison where u see bilateral loss of pain.

[ArchivalUser]

1 A patient have syringomyelia,anterior white commisure is effected
2 E Tight junction
3 D desruption of plazma membrane
4 F just make 2 by 2 table and calculate odds ratio

[ArchivalUser]

4> OR= ( DISEASE+/DISEASE-) IN EXPOSURE + /( DISEASE+/DISEASE-) IN NONEXPOSURE
OR= 250/50 / 250/150 = 250*150/250*50=3

[ArchivalUser]

17 CC
CMV has a unique method of escaping immune response it dec. the expression of MHC 1 and also expresses a decoy molecule. The normal for the MHC 1 molecule is that its made in the RER and then transported to the Cell membrane. If it get translocated to the cytosol, its likely to be degraded.
Ref Kaplan Immuno Chap 8[pg 99] viral strategies for evasion of the CMI response

[ArchivalUser]

Hello here is my explanation..
In an epidemiologic study of workers in the aniline dye industry, 500 workers with bladder cancer........

Which of the following is the odds ratio for the exposure variable?
ODD RATIO (OR)
Getting disease with exposure to a risk factor versus getting disease with non-exposure to that factor
OR= AD
BC

500 Workers with bladder cancer 200 without Bladder cancer
Exposure 250(A) 50(B)
No Exposure 250© 150(D)
AxD and CxD 250x150= 37,500 and 250x50= 12,500 and now divide
37,500/12,500 = 3. Answers is 3