1 / 15

ETHANOL METABOLISM

ETHANOL METABOLISM. CH 3 CH 3 CH 3 HCH CH C O O O _ O H H + Alcohol Dehy Aldehyde Dehy Ethanol Acetaldehyde Acetate FOMEPIZOLE INHIBITS ANTABUSE INHIBITS ALSO METRONIDAZOLE. OTHER ALCOHOLS. R R = H METHANOL R=CH 3 ETHANOL

tiffany
Télécharger la présentation

ETHANOL METABOLISM

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ETHANOL METABOLISM CH3 CH3 CH3 HCH CH C O O O _ O H H+ Alcohol Dehy Aldehyde Dehy Ethanol Acetaldehyde Acetate FOMEPIZOLE INHIBITS ANTABUSE INHIBITS ALSO METRONIDAZOLE

  2. OTHER ALCOHOLS R R = H METHANOL R=CH3 ETHANOL HCH R=CH2CH3 PROPANOL O R=CH2OH ETHYLENE GLYCOL H R=CHOHCH3 PROPYLENE GLYCOL ETC All react with alcohol dehydrogenase + NAD to give aldehydes, and then with aldehyde dehydrogenase + NAD to give the acids

  3. COMPETITION • SHORT CHAIN ALCOHOLS REACT QUICKLY WITH BOTH ENZYMES; LONGER CHAIN ARE SLOWER • BUT AFFINITY FOR ALCOHOL DEHY IS GREATER FOR ETHANOL THAN FOR METHANOL OR ETHYLENE GLYCOL • SO ETHANOL INHIBITS REACTION WITH THESE OTHER ALCOHOLS

  4. ETHYLENE GLYCOLANTIFREEZE FAST REACTIONS • CH2OH CH2OH CH2OH • CH2OH CHO COO- • ETHYLENE GLYCOL GLYCOLALDEHYDE GLYCOLATE SLOWER REACTIONS COO- COO- COO- CH2OH CHO COO- GLYCOLATE GLYOXYLATE OXALATE GLYCOLATE CAUSES THE ACIDOSIS OXALATE IS THE MOST LETHAL (BINDS Ca++)

  5. HOW TO DIAGNOSE IT • HISTORY OF INGESTION • HIGH ANION GAP ACIDOSIS NOT KETO OR LACTIC OR RENAL FAILURE (THE COMMON ONES) • CALCIUM OXALATE CRYSTALS IN URINE – A BIT LATE! • HYPOCALCAEMIA ? WITH TETANY • OSMOLAR GAP

  6. ANION GAP • Cations (+) Anions (-) • Na 140Cl 105 • K 4BIC 26 Ca + Mg 3 Albumin 10 • Others 1 Other proteins 2 • TOTAL 148 Lactate 1 • Na + K + 4 Ketones 1 • Others 3 • TOTAL 148 • Cl + BIC + 17 • So Na + K + 4 = Cl + BIC + 17 • (Na + K) - (Cl + BIC) = 17 – 4 = 13

  7. OSMOLAR GAP • MEASURED POSM – CALCULATED POSM • CALCULATION OF POSM • 2 X Na + GLUCOSE + UREA • THIS GAP IS NORMALLY 0 WITH SD 5 • NONIONIC SUBSTANCES SUCH AS ETHANOL, METHANOL, ETHYLENE GLYCOL, PROPYLENE GLYCOL, ISOPROPANOL, ACETONE, MANNITOL

  8. ANOTHER CLUE • LABORATORY ASKED “WHY IS OUR LACTATE NORMAL (1) AND BLOOD GAS MACHINE SAYS HIGH (17)?” • REPEAT, GET NEW SAMPLE, SAME RESULTS – THEREFORE: • CONSULT INTERNET – REPORT THAT SOME BLOOD GAS LACTATE PROBES (OUR TYPE!) REACT TO GLYCOLATE

  9. EXPLANATION OF DISCREPANCY • LABORATORY TEST IS DONE WITH AN ENZYME (L-LACTATE DEHYDROGENASE, USES NAD) THAT IS ABSOLUTELY SPECIFIC FOR L-LACTATE AND DOES NOT REACT WITH D-LACTATE OR GLYCOLATE • OUR BLOOD GAS MACHINE HAS A LACTATE ELECTRODE THAT USES A MICROBIAL LACTATE OXIDASE THAT REACTS WITH OXYGEN TO GENERATE H2O2 WHICH GIVES THE SIGNAL • THIS LACTATE OXIDASE IN OUR MACHINE IS PROMISCUOUS AND REACTS WITH D-LACTATE AND GLYCOLATE AND GIVES A SIGNAL THAT IS REPORTED AS LACTATE • OTHER BRANDS OF BLOOD GAS MACHINE HAVE LACTATE OXIDASES FROM DIFFERENT MICROBIAL SOURCES THAT DO NOT REACT THE WAY OUR MACHINE DOES

  10. PROPYLENE GLYCOL • THIS IS A “NON-TOXIC” SWEETISH SOLVENT USED TO DISSOLVE OR SUSPEND VARIOUS DRUGS TO MAKE THEIR ORAL ADMINISTRATION EASY • IT IS ALSO USED IN REFRIGERATOR COLD BRICKS AS A NONTOXIC WAY TO MAKE A SLUSH OF ICE CRYSTALS (ETHYLENE GLYCOL IS TOXIC, AS WE HAVE SEEN)

  11. PROPYLENE GLYCOL METABOLISM CH3 CH3 CH3 HCOH HCOH HCOH HCH HCO OCO- OH D-L PROPYLENE GLYCOL D-L LACTALDEHYDE D-L LACTATE THE L-LACTATE IS METABOLISED BY THE NORMAL PATHWAYS IN THE LIVER TO GLUCOSE ETC THE D-LACTATE IS NOT METABOLISED BUT IS EXCRETED IN URINE NORMALLY THE DOSE IS NOT ENOUGH TO CAUSE SIGNIFICANT D-LACTATE ACIDOSIS

More Related