NBME 16 body fluids question

[zeevee]

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Can someone explain this .

 

[Brunner gland]

I marked D and it was wrong..looks E

 

[zhopv10]

I would put E, endothelin-1 for A Is a vasoconstrictor if we constricted the pulm artery then there would be less flow to the capillaries/lymph. Phenylephrine would do the same. Decreasing oxygen conc would also constrict (remember that the lung is different from other organs in that the vessels constrict with hypoxia to shunt the blood elsewhere). Increasing co2 would do the same thing (less oxygen dalton's partial pressure law). Saline that is normal (9%) would be just adding fluid without changing the osmotic pressures so you would have more volume thus more pressure to "push" fluid out into the lymph. F would increase oncotic pressure and that would pull fluid back into capillaries not out into the interstitium/lymph.


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[walakin25]

just remember simple order of transit: capillaries --> interstitium --> lymph

 

[zeevee]

Thankyou

 

[zeevee]

Thankyou for helping me out can you please look into this as well ?

 

[thehundredthone]

Thankyou for helping me out can you please look into this as well ?

That is the phenomenon of natural transformation, where bacteria are able to incorporate exogenous DNA into their genome. The free DNA from lysed S. mitis is taken up by S pneumoniae. When DNAse is added, the free DNA is destroyed, hence there is nothing for the bacteria to incorporate into their genome.

Transduction requires the presence of a bacteriophage virus. Plasmid transfer requires two different live bacteria, point mutations will not occur across colonies so uniformly and neither will strand mispairing.

Also, I would advise not sharing screenshots of NBME material as it is copyrighted. It would be safer to ask about the concept being tested with some paraphrasing.

 

[zeevee]

Thanks .I get lost in the details of that question .

 

[Brunner gland]

35 yr old women is given 500mg of drug X I/V. Several mins later drug serum conc is 12.5 mg/dl. 2 hours later drug conc is 10mg/dl. Assuming drug has first order kinetics, what will be the serum conc in another 2 hours?

6
6.5
7
7.5
8
8.5

 

[Brunner gland]

case control study to see association between exposure of herbicide and non hodgkin lymphoma, controls are matched to cases by age, gender and race,exposure status determined by interviewing the subjects. on matched pair analysis OR is 3.2(95% CI 1.4 - 5.4). which of the following is most likely to affect the validity of this study?

Biased measurement of condition
Biased measurement of exposure
confounding by age
type 1 error
typer 2 error

 

[Brunner gland]

67 year women comes for health maintenance examination, her brother and mother have a history of colon ca, physician recommends colonoscopy but patient says she would prefer stool for occult blood. physician explains this test is not appropriate in this case because?

low sensitivity
low specificity
uncertain NPV
uncertain PPV
potential for false positive

 

[worldbeater]

You can comb through the longer discussion here:
http://forums.studentdoctor.net/threads/nbme-16-help.1059939/

35 yr old women is given 500mg of drug X I/V. Several mins later drug serum conc is 12.5 mg/dl. 2 hours later drug conc is 10mg/dl. Assuming drug has first order kinetics, what will be the serum conc in another 2 hours?

6
6.5
7
7.5
8
8.5

This was explained by Phloston and another poster, it's just a proportion. So 10/12.5 means 20% was lost and 80% remains. So in another 2 hours, 80% of 10 is 8. They even made the math easy for the student.

case control study to see association between exposure of herbicide and non hodgkin lymphoma, controls are matched to cases by age, gender and race,exposure status determined by interviewing the subjects. on matched pair analysis OR is 3.2(95% CI 1.4 - 5.4). which of the following is most likely to affect the validity of this study?

Biased measurement of condition
Biased measurement of exposure
confounding by age
type 1 error
typer 2 error

Exposure because the status is subjective, taken from an interview of the subjects

67 year women comes for health maintenance examination, her brother and mother have a history of colon ca, physician recommends colonoscopy but patient says she would prefer stool for occult blood. physician explains this test is not appropriate in this case because?

low sensitivity
low specificity
uncertain NPV
uncertain PPV
potential for false positive

Low sensitivity(ability to "rule in" a disease) because occult blood in your stool can be due to multiple conditions (hemorrhoids, polyps, etc), not just colon cancer

 

[Brunner gland]

Thank you!!