If you want to know about the unknown - Methaqualone is a sedative that increases the activity of the GABA receptors in the brain and nervous system, similarly to benzodiazepines and barbiturates. When GABA activity is increased, blood pressure drops and breathing and pulse rates slow, leading to a state of deep relaxation. These properties explain why methaqualone was originally mainly prescribed for insomnia An overdose can lead to nervous system shutdown, coma and death.[4] Additional effects are delirium, convulsions, hypertonia, hyperreflexia, vomiting, kidney failure, coma, and death through cardiac or respiratory arrest. It resembles barbiturate poisoning, but with increased motor difficulties and a lower incidence of cardiac or respiratory depression. The standard single tablet adult dose of Quaalude brand of methaqualone was 300 mg when made by Lemmon. A dose of 8000 mg is lethal and a dose as little as 2000 mg could induce a coma if taken with an alcoholic beverage.

Why is it not ovarian follicle cells? I thought the female analog of Sertoli and Leydig is theca/granulosa cells.

The presentation here seems to fit that of mesenteric vascular occlusion- postprandial pain that lasts 1 hour, food aversion, weight loss. The patient also has risk factors associated with mesenteric vascular occlusion- older than 60 years old, Hyperlipidemia, Hypertension, PMHx.

"The mesenteric circulation consists of three primary vessels that supply blood to the small and large bowel: the celiac artery, superior mesenteric artery (SMA), and inferior mesenteric artery (IMA). Blood flow through these arteries increases within an hour after eating due to an increase in metabolic demand of the intestinal mucosa.Chronic occlusion of a single vessel allows collateral blood flow to compensate, thus symptoms do not typically present until at least two primary vessels are occluded." https://www.ncbi.nlm.nih.gov/books/NBK430748/

Collaterals between SMA and IMA near the splenic flexure (Meandering Mesenteric artery). There is also collateral between Celiac Artery and SMA (Pancreaticoduodenal arcade).

Lastly, I know that there is a 3-cm ectatic aorta found on CT, but an aortic aneurysm would not produce these symptoms. Even if you thought that the symptoms were due to the AAA, you could still get to the correct answer if you use fahmed14's reasoning.

The disease here is fructose bisphosphatase deficiency. In it, IV glycerol or fructose doesn’t help because both enter the gluconeogenesis pathway below fructose bisphophatase. Galactose on the other hand enters above it. I don’t think you really need to know this to choose the correct answer since the clinical picture of fasting hypoglycemia that is corrected w/ some sort of sugar that can enter the gluconeogenesis pathway should clue you into the right answer.

I think they might be describing angina...not sure. TXA2 is responsible for platelet aggregation,so it may be contributing to thrombosis, thus ischemia to the cardiac tissue.

The pt had asthma (SOB, wakes up at night out of breath, has allergies). It asked for the precursor of leukotrienes, which is arachidonic acid. The prob gave him Montelukast or inhaled glucocorticoids.

What about the additional flow through the circumflex?

So this question was something I really struggled with. I didn't recognize that the presentation was of MERRF as someone stated below, and I know you don't need to know that to answer the question, but it would have been helpful. My biggest frustration was the wording of the biopsy results "abnormal accumulations of mitochondria." This annoyed me because the definition of ragged red fibers (which I'm assuming was their intention) is "accumulations of abnormal mitochondria." Those are two very different statements in my mind, lol. The first, to me, just means there's too much mitochondria, but the second means there's too much AND they aren't functioning properly. It's also just the fact of remembering all of the terms for ETC at the time of reading the question (i.e. I didn't think about the fact that ETC is also called cellular respiraton or just respiration).

I also didn't really understand fully what VO2max is = "VO2 max, also known as maximal oxygen uptake, is the measurement of the maximum amount of oxygen a person can utilize during intense exercise... and is based on the premise that the more oxygen consumed during exercise, the more the body will generate adenosine triphosphate (ATP) energy in cells... VO2 max is reached when your oxygen consumption remains at a steady state despite an increase in the workload. It is at this plateau that the [muscle] moves from aerobic metabolism to anaerobic metabolism" https://www.verywellfit.com/what-is-vo2-max-3120097.

Based purely on this definition, where VO2max = essentially the time at which aerobic switches to anaerobic respiration, my interpretation of too much mitochondria vs too much and bad mitochrondria didn't matter, because even when the mitochondria are functioning properly, they reach a point and switch to anaerobic, thus if there was too much normal mitochondria, this would occur faster because there would be more overall cellular respiration occuring, meaning the body would switch to anaerobic and utilize glycolisis to lactate for energy, stop utilizing the mitochondria, and thus VO2max would decrease.

HOWEVER.... because this is a MERRF question, the order of events is a little different, despite the outcome being the same (at least that's how I understand it). So, I think the key to any mitochondrial disorder is remembering that the mutations are almost certainly going to affect an encoded protein and thus a deficiency of that protein. One article that I found said that the tRNA mutations (as in MERRF) cause: "disrupt mitochondrial protein synthesis, decreasing the activity of Complex I and to a lesser extent Complex IV... which decreases respiration and lowers proton pumping, dramatically decreasing the membrane potential and proton electrochemical potential gradient across the mitochondrial inner membrane. The proton electrochemical potential gradient is the driving force for ATP synthesis and decreasing it substantially lowers the maximal rate of ATP synthesis." https://febs.onlinelibrary.wiley.com/doi/full/10.1046/j.1432-1327.1999.00066.x

Based on my understanding of oxidative phosphorylation, O2 consumption (i.e. taking the electron from complex IV and putting it on 1/2 O2 to create H2O and H+ drives the proton gradient which drives ATP production. Thus: deficient respiratory oxidation (i.e. mtDNA mutations of the ETC enzymes) leads to lowered O2 consumption (so lowered VO2 max) which then leads to lowered ATP production, and thus defective mitochondria. Then, lowered mitochondrial function leads to decreased aerobic respiration shunting ATP production to anaerobic respiration, driven by glycolysis, and thus increasing lactate levels.

Hope this helps! This took me WAY TOO LONG to figure out, lol, but hopefully I never freaking forget it, lol.

Also, if you want any more reading, I finally found an article that actually fully explains the biochemical and pathophysiology of mitochondrial myopathies: https://academic.oup.com/brain/article/126/2/413/332457

Sorry it's so long!

literally know every single name they can possibly call this

out of curiosity, how may people knew this? (dont be shy to say you did or didnt?)

My poverty education didn't ingrain this in me.

Can portal HTN contribute to hepatic encephalopathy?