MLS 422 Heme Derivatives

Exam 3 Part 1

Porphyrins stability, color, and fluorescence

stable, red-violet to red-brown, and fluoresce red

Porphyrinogens stability, color, and fluorescence

unstable, colorless, and do not fluoresce

Rate-limiting enzyme of heme synthesis

ALA synthase

Cutaneous porphyrias cause

excess of porphyrin

Acute porphyrias cause

excess of early precursors

Cutaneous porphyrias symptoms

photosensitivity, excess facial hair, lesions on hands, face, and ears

Acute porphyrias symptoms

abdominal pain, tachycardia, and psychiatric symptoms

Acquired porphyria causes and symptoms

liver disease, hereditary tyrosinemia and similar symptoms to acute

Cutaneous porphyria testing

pos porphyrins, neg PBG

Acute porphyria testing

pos PBG

Watson-Schwartz

PBG screen

Hoesch

PBG screen

Watson-Schwartz vs Hoesch

Both use Ehrlich’s reagent; Hoesch mixes it with strong acid, it is faster and more specific

HPLC w/ fluorescence

porphyrin quantitation

Ehrlich’s reagent

PBG and urobilinogen

Jendrassik-Grof (diazo reaction)

total and direct bilirubin

Caffeine-benzoate

accelerator for total bilirubin

Malloy-Evelyn

first clinically useful serum bilirubin method

Absorbance at 455nm minus 575 nm

direct spectrophotometric bilirubin (neonates)

Reflectance spectrophotometry

thin-film (dry-slide) bilirubin

Form of bilirubin that is toxic to nervous tissue

unconjugated

Adult Tbili reference range

0.3-1.0mg/dL

Prehepatic jaundice lab findings

unconjugated hyperbilirubinemia, no bilirubin in urine

Prehepatic jaundice cause

hemolytic anemia

Hepatic jaundice general cause

poorly functioning liver

Unconjugated hyperbilirubinemias (hepatic jaundice)

Gilbert syndrome (common), Crigler-Najjar syndrome (high mortality)

Conjugated hyperbilirubinemias (hepatic jaundice)

Dublin-Johnson syndrome, Rotor’s syndrome (both benign)

Posthepatic jaundice cause

biliary obstruction

Posthepatic jaundice lab findings

Increased serum conjugated and unconjugated bilirubin, conjugated bilirubin in urine, decreased urine urobilinogen, clay colored stool

Neonatal jaundice cause

increased hemolysis and deficiency of UDP-glucuronyl transferase

Kernicterus

accumulation of unconjugated bilirubin in the brain of infants