Transcutaneous cranial electrical stimulation with Limoge's currents has been shown to facilitate anesthesia/analgesia in surgical patients. However, the neurobiologic substrate of this effect ...remains unknown. The present study was designed to analyze the influence of transcranial electrical stimulation (TCES) on halothane requirements in rats and the contribution of the central endogenous opioid, alpha 2-adrenergic and 5-hydroxytryptamine (5-HT1 and 5-HT2) serotonergic systems to this effect. The influence of TCES on the MAC of halothane (MACH) and its reversibility by a subcutaneous 2 mg/kg naloxone injection were first determined in 20 rats using a randomized blinded protocol. MACH was decreased markedly in stimulated animals (TCES, n = 10) in comparison with sham-operated nonstimulated rats (controls, n = 10): MACH = 0.60 +/- 0.15, mean +/- SD, versus 1.07 +/- 0.05 vol%, P less than 0.001. In TCES animals, naloxone administration restored MACH values to the levels of controls but failed to affect MACH in controls. The influence of the duration of TCES applied prior to MACH determination was further investigated in 30 animals. The magnitude of MACH reduction was significantly increased with the cumulative duration of stimulation. For each duration of stimulation tested, administration of a 5-micrograms intracerebroventricular (icv) dose of the enkephalinase inhibitor thiorphan significantly enhanced TCES effects (P less than 0.05). Finally, the icv administration of a 15-micrograms naloxone dose appeared to reverse completely the MACH reduction elicited by TCES (n = 8, P less than 0.01).
Synthetic phosphatidylcholines have been separated by reversed phase chromatography. Columns of the acetate form of a Sephadex derivative containing long alkyl chains and dibutylamino groups were ...used in mixtures of chloroform, methanol and water. The mobility of a phosphatidylcholine was determined by the number of carbon atoms and the degree of unsaturation of the fatty acid chains.
Organic farming in Norway Sogn, O. (Centre Norvegien de l'Agriculture Biologique, Norsok (Norvege)); Alme, E
Alter Agri (France),
(Jan-Fev 2000)
39
Publication
A method is described for quantitative analysis of bile acids in urine. Urine is acidified and bile acids are extracted on an Amberlite XAD-2 column. Bile salts are converted to acids on an Amberlyst ...A-15 column and are separated into groups of unconjugated, glycine, taurine, monosulfated, and polysulfated conjugates using the lipophilic anion exchanger diethylaminohydroxypropyl Sephadex LH-20 (DEAP-LH-20). After solvolysis and hydrolysis, the deconjugated bile acids are purified on DEAP-LH-20, and are converted to methyl ester trimethylsilyl ether derivatives. Identification and quantitation of the individual bile acids is accomplished by computerized gas-liquid chromatography-mass spectrometry.
The daily excretion of bile acids in urine from healthy subjects was 6.4-11 µ moles. The mixture of bile acids was quite complex and differed from that in bile. About 30 bile acids were identified or partially characterized. Three of these were monosubstituted: lithocholic, allolithocholic, and 3β-hydroxy-5-cholenoic acids. Fourteen disubstituted bile acids included epimers of deoxycholic, allodeoxycholic, chenodeoxycholic, allochenodeoxycholic, and hyodeoxycholic acids. 3α-Hydroxy-12-keto-5β-cholanoic acid was the major ketonic bile acid and 3β,12α-dihydroxy-5-cholenoic acid was the major unsaturated bile acid in this group. Nine trihydroxy bile acids included cholic and allocholic acids, epimers of these compounds, hyocholic acid, and a 1-hydroxylated bile acid tentatively characterized as 1,3,12-trihydroxycholanoic acid. Cholestatic subjects excreted tetrahydroxycholanoates carrying hydroxyl groups in positions 1, 3, 6, 7, 12, or 23.
All monohydroxy and the predominant part of dihydroxy bile acids were present in the monosulfate fraction. Exceptions were 3α,12β-dihydroxy- and 3α-hydroxy-12-keto-5β-cholanoic acids, which were found mainly in the glycine conjugate fraction. Most of the trihydroxy bile acids were nonsulfated, and cholic and norcholic acids were the major unconjugated bile acids. The tetrahydroxy bile acids and hyocholic acid were present mainly in the taurine conjugate fraction, while 1,3,12-trihydroxycholanoic acid was predominantly found in the glycine conjugate fraction. Sulfation of trihydroxy bile acids was increased in patients with marked cholestasis. All bile acids in the monosulfate fraction were conjugated and carried the sulfate ester group at C-3. Significant amounts of di- and trisulfates were not found.
The results indicate selective mechanisms for sulfation, hydroxylation, and renal elimination of bile acid conjugates. Analysis of metabolic profiles of bile acids in urine may be a useful method in studies of the function of organs involved in bile acid metabolism.
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