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Based on the correct answer choice, the person is now in metabolic acidosis with respiratory compensation.
The correct answer choice is as listed above (all decreased). Note that whether metabolic acidosis is combined with primary respiratory alkalosis, which is an important teaching point I’ve argued the question writers are probably getting at, or even if just simple respiratory compensation for metabolic acidosis–both can have the same arrows. In this case, it’s not respiratory compensation. In ASA overdose, the respiratory alkalosis actually happens first. Ultimately, the metabolic acidosis dominates and the pH is almost always low. This mixed primary acid/base response to ASA toxicity is highly testable.
How long till the respiratory alkalosis turns into a metabolic/mixed picture?
@ali 12 hours is a good number to memorize but it can definitely happen much earlier.
From what I understand, the metabolic acidosis only presents 12h post ingestion, while she is only 3h. What do you think?
@yoav, It can definitely happen earlier. It’s more of a by 12 hours (not only beginning then).
I'm beginning to think that they don't actually care about how many hours lapse after the ingestion, but if we actually know the unique acid-base disturbance. I chose the wrong one, again because I was foolishly thinking about those 12 hours postintoxication
I think this is good rule of thmb in USMLE "a Right answer may or may not tick all the correct things but will NEVER have a wrong thing in it". So the ans choice we all chose has Bicarb inc. But this will never happen. at 3 hour we should have pure resp alkalosis with normal bicarb (as per uw). Or in this case decreased due to neutralization by organic salicylic acid. In Aspirin poisoning bicarb will nver increase.
Another important point- they probably gave her RR (30) to indicate that she is hyperventilating==> LOW CO2
I still don’t understand this one. Could you provide a better explanation?
The cDNA tag is tagging a constant region common to immunoglobulins, so it normally only finds the one band corresponding to that particular gene (the bands travel different amounts due to their differing size/weight). In the bone marrow sample, that gene has rearranged itself, so the cDNA clone instead tags multiple different genes that are of different sizes on the gel (each one has that same constant region the cDNA is tagging, but with different stuff around it such that the restriction enzyme has cut it up differently). I’d be happy for someone to step in and do a better job on that explanation.
A Southern blot starts by cutting DNA strands at a particular (short) site and running them through gel electrophoresis, so identical DNA sequences get cut at the same site and thus are the same length, so they are at the same place on the gel. If there's lots of different sequences, the restriction endonuclease (the scissors) cut the DNA at different places, leading to strands that were the same length originally but are now lots of different lengths -> different places on the gel. But how do you know this is the same gene, just with different mutations? The Southern blot uses a probe to look for a more specific (long) region of DNA that you know is in the target gene. So even though there are mutations causing the less-specific endonuclease to cut the DNA at different parts, the overall architecture of the gene is similar enough that the probe can bind, thus we know it's the same gene. (And in bone marrow WBCs, the mechanism here is genetic rearrangement.)