Step I NBME 15 - some doubts

[zeevee]

Vision screening performed on 4000 people who are older than 65 years .Cataracts are found in 200 .Which of the following describes annual incidence of cataract in this population ?
a) 0.2 %
b) 0.5 %
c) 2.0%
d) 5.0%
e) unable to calculate due to insufficient data

 

[Postictal Raiden]

Vision screening performed on 4000 people who are older than 65 years .Cataracts are found in 200 .Which of the following describes annula incidence of cataract in this population ?
a) 0.2 %
b) 0.5 %
c) 2.0%
d) 5.0%
e) unable to calculate due to insufficient data

It's E right? Incidence is New cases/susceptible population. Prevalence on the other hand, is all cases/entire population (5% in this case).

 

[zeevee]

Q2 : what is the connection of IKB with NFKB ?

Phosphorylation of IkB leads to inactivation of Ikb or activation ?

 

[zeevee]

It's E right? Incidence is New cases/susceptible population. Prevalence on the other hand, is all cases/entire population (5% in this case).

Yes but how .
Isnt 200 cases new cases and susceptible population is 4000-200 ?

 

[Postictal Raiden]

Yes but how .
Isnt 200 cases new cases and susceptible population is 4000-200 ?

No, the 200 is the total number of cases, period. We don't know if these are new cases or they have always existed. Yes, susceptible population would be 3800.

 

[zeevee]

Q3 -What is the difference between immunohistochemistry and flow cytometry ? Both identify CD markers ?

 

[Chubster]

Q3 -What is the difference between immunohistochemistry and flow cytometry ? Both identify CD markers ?

Both are used to identify different cell populations and do often use CD markers.

Immunohistochemistry is more useful for staining sections of tissue while in flow cytometry, cells are stained in solution.

 

[recycledpaper]

Q2 : what is the connection of IKB with NFKB ?

Phosphorylation of IkB leads to inactivation of Ikb or activation ?

IkB holds onto NFkB to keep it from going to the nucleus and doing it's thang.

Once IkB is phosphorylated by IkB kinase (IKK), then it release the NFkB, so it can go do its... thang.

 

[Burnt Almonds]

Yes but how .
Isnt 200 cases new cases and susceptible population is 4000-200 ?

I think what you're missing is understanding the difference between incidence and prevalence. They are distinct terms.

This question stem does not give you any information about time or "when" these 200 cases developed...so you have no idea what the incidence is.

 

[Transposony]

Q3 -What is the difference between immunohistochemistry and flow cytometry ? Both identify CD markers ?

Immunohistochemistry stains cells in tissue samples but with flow cytometry you can separate and count various cells depending on their characteristics and therefore more sensitive.