uWorld 21 Flashcards
what is renal osteodystrophy
abnormal bone path seen in chronic kidney disease
PTH increase mobilizes calcium from bones by bone formation, causing OSTEOPENIA and pathologic bone changes similar to those seen in primary hyperthyroidism (OSTEOFIBROSA CYSTICA)
pts can also develop PTH resistance, resulting in low-turnover aplastic bone disease and OSTEOMALACIA
small intestinal bacterial overgrowth is characterized by what
overproduction of VITAMIN K and FOLATE, associated with nausea, bloating, abdominal discomfort, and malabsorption
B12, iron, zinc and fat soluble vitamins (except K) all decreased
what happens in the closed-ended gastroducodenal limb that occurs in a gastric bypass surgery
bacteria can proliferate (small intestinal bacterial overgrowth) and ferment any food that may be diverted into this segment
what enzyme plays a crucial role in imprinting
S-adenosyl-methionine (SAM)- a methyl donor
CYTOSINE methylation
what is an epigenetic process by which eukaryotic organisms modify genes expression without altering genetic code
DNA methylation (DNA methyltransferase)
methylation of cytosine-guanine dinucelotide repeats (CpGs) in the promoter region of genes effectively silences transcription of those genes
how does DNA methylation play a role in fragile X
methylation happens at CG repeats and fragile X is CGG trinucleotide repeats lead to hypermethylation of cytosine residues and FMR1 inactivation
what is epistasis
a phenomenon in which the allele of one gene affects the phenotypic expression of alleles in another gene
what is first-line treatment of major depressive disorder that DOES NOT cause sexual dysfunction
BUPROPION
norepi and dopamine reuptake inhibitor
also good for treating depression associated with hypersomnia and low energy
what is escitalopram
SSRI
what is a highly sedating antidepressant that can be helpful for patients with insomnia
TRAZODONE
the dorsal pancreatic bud forms what
pancreatic tail, body, most of the head, and the small ACCESSORY DUCT
the ventral pancreatic bud forms what
uncinate process, portion of the pancreatic head, and the proximal portion of the MAIN PANCREATIC DUCT
how is the main pancreatic duct (of Wirsung) created
fusion of the remainder of the accessory duct with the ventral duct
what is PANCREATIC DIVISUM
when ventral and dorsal pancreatic buds fail to fuse (usually occurs in week 8); the pancreatic secretions are instead drained via two separate duct systems
dominant dorsal duct (of SANTORINI) opens into the duodenum via the minor papilla, and is responsible for draining the majority of the pancreas
smaller ventral duct (of Wirsung) opens into he major papilla, and functions to drain the inferior/posterior portion of the head and unite process
how is pancreatic divisum diagnosed
can cause recurrent pancreatitis
normally incidental finding on imagining studies or at autopsy
what removes RNA primer as well as damaged DNA segments
5’ → 3’ exonuclease activity
what performs proofreading function that removes and replaces mismatched nucleotides on the newly formed daughter strands
3’ → 5’ exonuclease
defective in LYnch Syndrome (HNPCC)
what does an AP endonuclease do
cleaves 5’ end
used in base-excision repair
important repair of spontaneous/toxic deamination
how do nitrites cause poisoning
inducing conversion of heme iron into OXIDIZED ferric iron → methemoglobin formation
what does methemoglobinemia do to the skin and O2 in the blood
DUSKY discoloration (similar to cyanosis)
unable to carry oxygen, state of functional anemia is induced
pyruvate kinase deficiency causes what
chronic hemolytic anemia
splenomegaly
iron overload
result of impaired erythrocyte survival
what is acid maltase and what does a deficiency cause
ALPHA-1,4-GLUCOSIDASE deficiency Pompe Disease (type II glycogen storage disease)
cardiomegaly, macroglossia, hepatomegaly, and profound muscular hypotonia
blood glucose levels normal
abnormal GLYCOGEN ACCUMULATION in LYSOSOMES vesicles is seen on muscle biopsy
what is von Gierke disease (Type I glycogen storage disease)
GLUCOSE-6-PHOSPHATASE deficiency hepatomegaly and steatosis fasting hypoglycemia lactic acidosis hyperuricemia and hyperlipidemia
what is Cori Disease (type III glycogen storage disease)
DEBRANCHING ENZYME (alpha-1,4-transferase and alpha-1,6-glucosidase) deficiency
hepatomegaly
ketotic hypoglycemia
hypotonia and weakness
abnormal glycogen with very short outer chains