Diseases Flashcards

1
Q

Myasthenia Gravis

A

Antibodies block Ach (breakdown in communication between nerves and muscles)

Symptoms: muscle weakness, double vision, fatigue

Treatment: acetylcholinesterase inhibitors (physostigmine)

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2
Q

Lead poisoning

A

Pb (Lead) inhibits delta-aminolevulinic acid dehydratase (ALAD)

Symptoms: abdominal pain, sideroblastic anemia, headache, irritability

Treatment: Ca-EDTA w/ dimercaprol (Pb has a higher affinity for EDTA than Ca 2+, Pb binds to EDTA and is then excreted in urine). Children can use succimer

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3
Q

Fanconi-Bickel syndrom (jekyll-Hyde)

A

GLUT2 deficiency in liver, pancreatic B cells, proximal renal tubules. Autosomal recessive

Affects: Hepatomegaly (enlargement of liver), stunted growth, failure to thrive

Symptoms: hyperglycemia postprandial (post meal), hypoglycemia between meals, serum insulin normal (B cells fail to sense increase in glucose)

Treatment: Small frequent meals, electrolytes, Vit D/phosphate supplements

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4
Q

Drug-induced lupus erythematosus

A

Mutations in enzymes that carry out acetylation (how body metabolizes drugs)

Affects: slow rate of drug acetylation. Drugs concerted to toxic by-products and this triggers antibodies

Symptoms: Muscle and bone pain, rashes, inflammation of lungs and heart, fever, fatigue

Treatment: NSAIDs, wait for effects to wear off

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5
Q

Niemann-Pick disease

A

Think liPid…Pick…

Harmful quantities of lipids accumulate in the spleen, liver, lungs, bone marrow, and the brain.

Affects: deficiency in sphingomyelinase (sphingomyelin accumulates in lysosomes)

Symptoms may include lack of muscle coordination, neurologic damage (mental retardation, seizures, ataxia (loss of body control) spasticity (muscle tightness), enlarged liver and spleen, cherry red spot in eye

Treatment: none

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6
Q

Spur cell anemia

A

Elevated cholesterol in erythrocyte membrane

Symptoms: rigid RBC’s break!

Treatments: associated w/ beta lipoproteinemia and advanced stages of alcoholic cirrhosis (chronic liver damage leading to scarring and failure)

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7
Q

Cystinuria

A

Defect in transporters for cystine (not Cysteine-2 cysteine=cystine), ornithine, lysine, and arginina (COLA). Autosomal recessive

Affects: forms cystine crystals in kidneys (kidney stones)

Symptoms: Renal colic (waves of abdominal pain), identified by + nitroprusside test

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8
Q

Hartnup disease

A

(“Trypping” infants)

Defect in transporters for nonpolar/neutral AA (tryptophan). Autosomal recessive

Affects: infancy

Symptoms: failure to thrive, nystagmus (involuntary eye movement), intermittent ataxia, tremor, photosensitivity

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9
Q

Cystic Fibrosis

A

Defective Cl- transport, autosomal recessive. Defective CFTR causes buildup of Cl- (and salt) in airway followed by water. Mucus secretions are usually thin become thick

Symptoms: bacterial infections, cough

Treatment: antibiotics

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10
Q

Peroxisome biogenesis disorders (Zellweger spectrum)

A

Defect in 1 of 12 genes responsible for peroxisome assembly. Zellweger Syndrome is the worst disorder on the spectrum

Affects: affects synthesis of peroxisomes, peroxisomes are thus not present. They are present at birth and fatal within the first year

Symptoms: hypotonia (weak muscle tone), hearing loss, vision loss, feeding problems, seizures, problems caused by breakdown of myelin (insulates nerve fibers in brain)

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11
Q

Lysosomal storage disorders

A

Lysosomes lack a necessary enzyme and can’t break down material in cell, it builds up and kills cell.

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12
Q

Familial hypercholesterolemia (type 2a/2b)

A

LDL receptor is completely (2a) or partially (2b) defective

Cholesterol, LDL=increased. Triacylglycerol normal (2a), increased (2b), VLDL increased (2b)

Symptoms: Atherosclerosis. Early MI (as young as 20)

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13
Q

Maple Syrup Urine Disease

A

(hungry lumberjacks)
Branched chain α-ketoacid dehydrogenase (BCKD). Same coenzymes as PDC. Autosomal recessive

Toxic levels accumulate in blood. Damage brain, mental retardation

Symptoms: Smell of burnt maple sugar in urine

Treatment: synthetic diet w/ limited BCAA’s. W/ mild forms: supplement cofactors (esp. thiamine–>TPP)

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14
Q

Homocystinuria/hyperhomocysteinemia

A

1) Homocysteine methyltransferase: deficiency B6, B12, folic acid
2) Cystathionine B-synthase: genetic defect

Affects: 1) Homocysteine–>affects metabolism of Met (using THF)
2) Homocysteine–>cystathionine

Symptoms: Atherosclerotic heart disease and stroke

Eye lens dislocation, osteoporosis, mental retardation

Treatment: Vitamin supplementation might help

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15
Q

Tyr–>dopa–>dopamine–>norepinephrine–>epinephrine

A

Tyrosinase deficiency prevents–> melanin (albinism)

MAO and COMT degrade catecholamines into HVA and VMA (can be diagnostic of pheochromocytoma-tumor of adrenal medulla)

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16
Q

Thyroglobulin (made by follicular cells of thyroid gland), contains about 120 Tyr residues

Tyr–>thyroglobulin

A

Thyroglobulin helps make T3, T4

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17
Q

Acetaminophen detox/Glutathione

A

GSH (glutathione) helps protect RBC’s

Acetaminophen overdose decreases GSH. Leads to increased GGT, marker for atherosclerotic cardiovascular disease (CVD)

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18
Q

Carbamoyl phosphate synthetase II (cytosolic)

A

First step de novo pyrimidines.
Stimulated by PRPP
Inhibited by UTP

Cytosolic carbamoyl phosphate–>orotic acid–>UMP

Defect in UMP synthase can lead to orotic aciduria

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19
Q

Sulfa drugs

A

Inhibits bacterial enzyme from converting PABA–>Folate, which disrupts DNA replication

Doesn’t affect humans b/c we don’t get folate in diet

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20
Q

Methotrexate

A

Dihydrofolate reductase (converts dietary folate to active tetrahydrofolate in liver)

Methotrexate inhibits DHF reductase

Inhibits DNA (target: cancer)

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21
Q

Severe combined immunodeficiency (SCID)

A

“bubble boy”

Adenosine deaminase (ADA) deficiency. Excess ADA–>hemolytic anemia-destroying RBC’s (so it’s a “goldilocks” amount)

High levels adenosine–>AMP/ADP–>dATP–>inhibits ribonucleotide reductase

Symptoms: B and T cells crippled

22
Q

Gout

A

Build-up of uric acid in blood.

Primary hyperuricemia-overproduction of uric acid

Secondary hyperuricemia-underexcretion of uric acid

Painful joints and kidney damage due to sodium urate deposits

Treatment: allopurinol: blocks xanthine oxidase
Colchicine: blocks inflammatory response from “attacking” sodium urate crystals in joints

Avoid high purine diet (meat, seafood, alcohol)

23
Q

Lesch-Nyhan syndrom

A

No HGPRT

Effects: Hypoxanthine–> IMP
Guanosine–>GMP
Not possible

Symptoms: x-linked PRPP increase. Severe gout: self-mutilation, mental retardation

24
Q

Acyclovir

A

Anti-viral drug

Thymidine kinase phosphorylates Acyclovir

Effects: Undergoes phosphorylation by viral thymidine kinase to acyclo GMP–>acyclo GTP. It lacks 3’ OH, leads to termination of DNA replication

Promotes the healing of sores produced by chickenpox, shingles, genital herpes

25
Q

Diabetes mellitus (diabetes)

A

Type 1: decreased insulin output by pancreas
Type 2: decreased insulin sensitivity by target tissues (strongly associated w/ obesity)

Effects: Fasting glucose level >120 mg/gL is indicative of diabetes

Symptoms: polyuria, polydipsia, heart disease, stroke, blindness, kidney dysfunction, etc

Treatment: Insulin injections

26
Q

PPP G6P deficiency

A

G6PD reduces NADP+ to NADPH which then is used to reduce glutathione. Glutathione helps to maintain RBC membrane integrity by getting rid of ROS. W/o glutathione, RBC membranes break

Symptoms: hemolytic anemia

27
Q

Von Gierke disease and GSD 1B

A
  • Von Gierke disease (GSD 1A)-autosomal recessive
  • Glucose 6 phosphatase deficiency (inside SER lumen)
  • GSD 1B: defective transport protein that moves G6P into SER lumen

Effects: Both-free glucose not released into blood

Symptoms: Both-hypoglycemia while fasting, lactic acidosis, hepatomegaly, hyperlipidemia

Treatment: liver transplant or surgical transposition of hepatic portal vein

Eating uncooked cornstarch before bed

28
Q

Pyruvate dehydrogenase deficiency

A

X linked, generally related to E1 subunit of PDC

Effects: Male infants

Symptoms: increased serum pyruvate and lactate levels, neonatal lactic acidosis

Treatment: B1, lipoid acid, biotin supplements (biotin serves as cofactor for pyruvate carboxylase)

  • Dichloroacetate-PDK inhibitor
  • Ketogenic diet to minimize pyruvate formation (ketogenic AA’s Lys and Leu can be used to form acetyl-CoA thus bypassing PDC)
29
Q

Beriberi (dry)

A

Thiamine (B1) deficiency

Affects cardiovascular function (blood test for thiamine levels). OFten seen in alcoholics b/c alcohol inhibits thiamine absorption–>Wernicke-Korsakoff

Symptoms: Weight loss, shortness of breath, difficulty walking, mental confusion, lack of coordination

Thiamine supplementation, other water-soluble vitamins

30
Q

Wernicke-Korsakoff Syndrome (wet)

A

Thiamine pyrophosphate (cofactor for alpha-ketoglutarate dehydrogenase)

Thiamine deficiency caused by ethanol inhibiting its absorption

Increased blood levels of pyruvate and alpha-ketoglutarate b/c of impaired PDC and alpha-ketoglutarate dehydrogenase which requires thiamine pyrophosphate as cofactor

Treatment: Thiamine supplementation, other water-soluble vitamins

31
Q

Pyruvate decarboxylase deficiency

A

More pyruvate–>lactic acid (rather than oxaloacetate)
Autosomal recessive

Effects: Lactic acid high in blood

Symptoms: In infancy, seizures, hypotonia, ataxia

32
Q

Acid-Base balance and the kidneys

A

Kidneys regulate blood pH. They can remove H+ in form of NH4+ (ammonium) and reabsorb bicarbonate (HCO3-).

33
Q

Biological oxidation

A

Biological oxidation provides most the energy for aerobic metabolism.

34
Q

Diabetic ketoacidosis

A

Marked by hyperglycemia and low blood pH, leads to uncontrolled diabetes. Lack of insulin prevents glucose being taken up by cells to make energy. The body starts degrading FA’s for energy and this generates ketone bodies (which lower blood pH). Symptoms: dehydration, vomiting, confusion, coma.

Treatment: insulin and fluids

35
Q

Catalytic triad in serine proteases, includes which AA’s?

A

His, Asp, Ser (HAS)

36
Q

Enteropeptidase activates trypsin from trypsinogen.

A

.

37
Q

Inhibition of metalloenzymes

A

Metalloenzymes (enzymes that require metal cofactors, i.e. Mg 2+ and Zn 2+) are inhibited by chelating agents that bind and remove these metals. An example=ethylenediaminetetraacetic acid (EDTA) inhibits metalloenzymes

38
Q

Troponin in myocardial infarction

A

Calcium binds to troponin and changes its conformation. This is transmitted to tropomyosin and then allows myosin to bind to actin filaments and then allows muscle contraction.

39
Q

Enzymes useful for medical diagnoses

A

Bone disease: alkaline phosphatase

Obstructive liver disease: sorbitol dehydrogenase or lactate dehydrogenase (LDH-5)

Prostatic cancer: acid phosphatase

Acute pancreatitis: amylase

Muscular dystrophy: AST

Liver disorder: ALT

40
Q

Irreversible steps in glycolysis:

A

Glucose–>G6P (hexokinase)
F6P–>F1,6bP (phosphofructokinase)
Phosphoenolpyruvate–>pyruvate (pyruvate kinase)

41
Q

Gluconeogenesis- bypass step enzymes

A

PEP carboxykinase pyruvate carboxylase
Fructose 1,6-bisphosphatase
Glucose 6-phosphatase

42
Q

Pentose phosphate pathway

A

Causes hemolytic anemia b/c of deficient levels of NADPH in red cells

43
Q

Depriving cells of GMP and dGTP

A

The oxidation step when converting IMP to XMP allows for therapeutic intervention. Enzyme is IMP dehydrogenase is targeted by drugs such as the immunosuppressant Mycophenolic acid and this disrupts DNA replication in B and T cells by by depriving cells of needed dGTP. Helps prevent graft rejection

44
Q

Nitrogen balance

A

+ balance when growing
- balance=malnutrition

BUN test (blood, urea, nitrogen)

45
Q

Aminotransferases in clinical setting

A

AST=liver disease. Elevated in later stages of disease

AST=muscle

46
Q

Tetrahydrobiopterin (THB)/dihydrobiopterin

A

THB is cofactor in hydroxylations of aromatic amino acids and in making NO.

THB is made from GTP and regenerated by NADPH. Not having enough THB leads to PKU (also less dopamine, norepinephrine and serotonin).

47
Q

Patients w/ hyperthyroidism disorders (Graves disease) are treated w/:

A

carbimazole and propylthiouracil

48
Q

Creatine

A

Presence of cardioselective isoform of creatine kinase (CK-MB) in serum is diagnostic of myocardial infarction (MI) (peaks 10-24 hrs after MI)

49
Q

Carbamoyl phosphate synthetase

A

Used in de novo synthesis of pyrimidines. Orotic acid is intermediate in pathway for making UMP. A defect in UMP synthase leads to orotic acid–>orotic aciduria. (not accompanied by hyperammonemia or a reduction in BUN levels)

50
Q

Cardiotonic drugs

A

Ouabain and digoxin are contraction inducing/cardiotonic drugs

Inhibit Na+/K+ ATPase on cardiac myocytes. Lead to increase in intracellular Na+ and increase in Ca 2+ b/c of slowing of NCX (Na-Ca exchanger)

More Ca results in stronger contraction