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NBME 21 Answers

nbme21/Block 3/Question#7
A 65-year-old man comes to the physician ...
DNA fragmentation🔍

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 +17  upvote downvote
submitted by feronie(17),

Orchiectomy = ↓ testosterone production = ↓ DHT => prostate cells undergo apoptosis. (This mechanism is similar to using 5α-reductase blockers to treat BPH.)

Apoptosis is characterized by DNA fragmentation (pyknosis, karyorrhexis, karyolysis).

hungrybox  DNA fragmentation histopath: https://i.imgur.com/nxYW8vL.png Note that degradation in apoptosis is progressive. From pyknosis -> karyorrhexis -> karyolysis. Aka condensation -> fragmentation -> complete dissolution. +9  

With the drop in testosterone (and therefore DHT), some of the prostate cells will undergo apoptosis. Apoptosis = DNA fragmentation (180 bp segments).

Alternatively, all the other options pointed to things that would actually increase testosterone production and its effects; orchiectomy would obviously not do that.

 -7  upvote downvote
submitted by step1soon(26),

Orchiectomy: One or both testicles is removed through a small cut in your scrotum. tissue removal from body → no nutrients → cell death

  • hall mark of cell death = DNA fragmentation

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