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someone who is taking only IV glucose will have problems synthesizing what?
- things derived from arachidonic acid
- cycloxygenase -> prostagladins (anti-inflammation, cAMP stimulation), thromboxane synthase -> thromboxane A2 (vasoconstriction, platelet aggregation)
- lipoxygenase -> leukotrienes (chemotaxis, constriction of sm. muscle/bronchioles)
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What can raise HDL?
- niacin
- exercise (12 mi/wk)
- mutations in CETP, cholesterol esterase transfer protein
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What is the composition of surfactant in the lungs that preterm infants lack?
- phosphatidylcholines: DPPC (dipalmitoylphosphatidylcholine)
- secreted by type II pneumocytes
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ketogenic v. glucogenic aa's
- aa's whose metabolism leads to pyruvate or TCA cycle intermediates = glucogenic
- acetylCoA/acetoacetylCoA = ketogenic
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Maple syrup urine disease
- deficiency in branched-chain alpha-keto acid dehydrogenase
- decarboxylates leucine, isoleucine, and valine
- fatal in first weeks of life
- buildup of ile, val, leu causes neurological problems
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cofactor needed to transaminate aa's
B6 or pyridoxine
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What inhibits and what activates pyrimidine synthesis?
- Inhibit: UTP
- Activate: ATP, PRPP
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Causes of gout
- undergoing chemotherapy of a bulky tumor
- Deficiency in hypoxanthine-guanine phosphoribosyltransferase (Lesch-Nyhan)
- elevated levels of 5-phosphoribosyl-1-pyrophosphate (PRPP)
- underexcreting uric acid
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How would cancer cells become resistant to methotrexate?
Overproduction of dihydrofolate reductase
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What decreases triglyceride levels?
- Decreases:
- Insulin
- Gemfibrozil (fibrates) - specifically decreases VLDL
- Fasting
- HMG-CoA-reductase inhibitors (statins)
- Increases:
- Estrogen
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If you pierced the skin lateral to the rectus abdominis, you'd pass through:
skin, superficial fascia, external abdominal oblique, internal abdominal oblique, transversus abdominis, transversalis fascia, extraperitoneal fat, parietal peritoneum
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Anemia + iron deficiency due to chronic infections. What are hepcidin and ferroportin levels?
- increased plasma level of hepcidin
- decreased ferroportin activity in macrophages
- decreased ferroportin activity in duodenal enterocytes
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protein energy malnutrition
- Kwashiorkor - inadequate intake of protein -> edema (due to hypoalbuminemia)
- Marasmus - inadequate calories -> no edema
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Phenylketonuria (PKU)
- defective phenylalanine hydroxylase (PAH)
- uses tetrahydrobiopterin (BH4) cofactor
- mental retardation (but not at birth) - must begin diet 7-10d after birth
- hyperphenylalanemia may inhibit transport of other aa's into brain, decreased synth of neurotransmitters
- treatment: diet low in F - still an essential aa
- if expectant PKU mom has d/c diet, she must resume it for the health of the unborn child
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alkaptonuria
- homogentisate oxidase defect, autosomal recessive
- arthritis, darkening of urine upon standing in infants
- relatively harmless, eventual darkening of sclera and cartilage
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maple syrup urine disease
- branched-chain ketoacid DH
- autosomal recessive
- non-specific symptoms within the first weeks of life
- CNS toxicity later in life
- treatment: diets low in leucine, isoleucine, valine. Dialysis if acidosis is too severe
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causes of hypercalcemia
hyperparathyroidism, hemochromatosis, hypothyroidism
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trabecular v. cortical bone
- trabecular: axial, more active metabolically, first site of osteoporosis
- cortical: peripheral bone
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osteoporosis
- resorption exceeds bone formation
- ratio of mineral to matrix remains normal
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