q.2 - uragan

[ArchivalUser]

Thank you uragan. I wish I could have understood your statement...lol....must learn Russian too for the sake of usmle )

Good q

[ArchivalUser]

it is kinda a Good Mnemonic for U guys : CO(carbon monoxide), CO(cytochrome oxidase), CN(cyanide) .."love each other".

but beside CO(carbon monoxide) also dec. O2 saturation by binding the active sites on Hb.

[ArchivalUser]

@Psycho u r welcome ..happy studying

and guys, do you remember the Rx of CN poisoning, steps:?

[ArchivalUser]

Nitrite....oxidize Hb to methhemoglobin...it binds the cyanide,then cytochrome oxidase can function normally

Thiosulfate is also can be used ..binds the cyanide....Thiocyanate...it is excreted by renal

[ArchivalUser]

First: Nitrite
Followed by: Thiosulfate

First:
some Hb----(Nitrite)---->Met-Hb, which grab CN and become-->Cyanomet-Hb

Next:

Cyanomet-Hb-----(Thiosulfate)----->Hb + Sulfite + Thiocyanate

-Thiocyanate excreted in urine

[ArchivalUser]

Hi Sarim..you mean both drugs should be used to detoxify the CN ? okay I didn't know.
Thank you

[ArchivalUser]

thanx uragan nice quetion
so the right answer is C
nice menomic

[ArchivalUser]

yes maryam.......it is given in Goljan's RR first chapter. and in kaplan Biochem video.

Beside that other antidot is "Hydroxocobalamine"

which convert CN------->Cyanocobalamine (which is harmless)

-the difference b/w the above two:
Met-Hb--------------- detoxify CN in vascular compartment only(b4 CN reach inside the cells)
Hdroxocobalamine--- act BOTH on vascular compartment CN as well as with in the cell CN.

[ArchivalUser]

Thank you very much

[ArchivalUser]

he he he, he told me Think better

Somehow I saw CO and focused on it. I agree, than CN inhibit cyto.

@psycho, I am good, trying to go through NBME 11 right now. A lot of points to cover in a small amount of time.