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M Evans

Publications and source records attributed to M Evans.

At least 379 records · Page 21Linked to original sources
PubMed1981

Reversal by naloxone of the effects of chronic administration of drugs of dependence on rat liver and brain tryptophan metabolism.

1. Chronic administration of ethanol, morphine, nicotine or phenobarbitone has previously been shown to enhance rat brain 5-hydroxytryptamine (5-HT) synthesis by increasing the availability of circulating tryptophan to the brain secondarily to the NADPH-mediated inhibition of liver tryptophan pyrrolase activity. 2. Naloxone reverses the above enhancement of 5-HT synthesis and the accompanying increase in tryptophan availability to the brain and the inhibition of liver tryptophan pyrrolase activity. 3. It is suggested that naloxone exerts these effects by antagonizing the chronic drug-induced increase in liver [NADPH]. 4. Naloxone increases serum corticosterone concentration in rats chronically treated with the above four drugs of dependence. Possible explanations of this effect are discussed.

Animals↗
PubMed1981

The mechanism of the antagonism by naloxone of acute alcohol intoxication.

Naloxone lowers blood-ethanol concentration and causes a simultaneous reversal of the disturbances in the redox states of the hepatic nicotinamide-adenine dinucleotide (phosphate) couples in acutely-ethanol-intoxicated rats. It is suggested that these effects of naloxone form the basis of its antagonism of acute alcohol intoxication.

Acute Disease↗
PubMed1981

Medicine and stamps.

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History, Modern 1601-↗
PubMed1981

A comparison of oral and intravenous indomethacin dispositions in the premature infant with patent ductus arteriosus.

Plasma concentrations of indomethacin were studied in 18 premature infants exhibiting significant patent ductus arteriosus (sPDA) after either intravenous or oral drug administration. Oral absorption of indomethacin was prolonged and bioavailability, based on area under the curve (AUC), was less than 20%. The mean volume of distribution for indomethacin was 0.36 l/kg and showed only a small variation between subjects. The drug elimination half-life ranged from 10-25 hours and demonstrated a significant correlation with gestational age. There was no evidence to support dose-dependent clearance or enterohepatic circulation in this study. Side effects of indomethacin were limited in one infant. No significant changes were observed in hematocrit, platelet count, and serum creatinine. The results from this study support the continued use of intravenous sodium indomethacin trihydrate at doses of 0.2 mg/kg and intervals of 18-24 hours for pharmacological treatment of sPDA.

Administration, Oral↗
PubMed1980

Inhibition of rat brain tryptophan metabolism by ethanol withdrawal and possible involvement of the enhanced liver tryptophan pyrrolase activity.

1. Chronic ethanol administration to rats was previously shown to enhance brain 5-hydroxytryptamine synthesis by increasing the availability of circulating tryptophan to the brain secondarily to the NAD(P)H-mediated inhibition of liver tryptophan pyrrolase activity. 2. At 24h after ethanol withdrawal, all the above effects were observed because liver [NAD(P)H] was still increased. By contrast, all aspects of liver and brain tryptophan metabolism were normal at 12 days after withdrawal. 3. At 7--9 days after withdrawal, brain 5-hydroxytryptamine synthesis was decreased, as was tryptophan availability to the brain. Liver tryptophan pyrrolase activity at these time-intervals was maximally enhanced. 4. Administration of nicotinamide during the withdrawal phase not only abolished the withdrawal-induced enhancement of tryptophan pyrrolase activity on day 8, but also maintained the inhibition previously caused by ethanol. Under these conditions, the withdrawal-induced decreases in brain 5-hydroxytryptamine synthesis and tryptophan availability to the brain were abolished, and both functions were enhanced. Nicotinamide alone exerted similar effects in control rats. 5. It is suggested that ethanol withdrawal inhibits brain 5-hydroxytryptamine synthesis by decreasing tryptophan availability to the brain secondarily to the enhanced liver tryptophan pyrrolase activity. 6. The results are discussed in relation to the possible involvement of 5-hydroxytryptamine in dependence on ethanol and other drugs.

Animals↗
PubMed1980

Biphasic effect of acute ethanol administration on rat liver tyrosine-2-oxoglutarate aminotransferase activity.

1. Acute ethanol administration causes a biphasic change in rat liver tyrosine aminotransferase activity. 2. The initial decrease is significant with a 200 mg/kg dose of ethanol, is prevented by adrenoceptor-blocking agnets and by reserpine, but not by inhibitors of ethanol metabolism, and exhibits many of the characteristics of the inhibition caused by noradrenaline. 3. The subsequent enhancement of the enzyme activity by ethanol is not associated with stabilization of the enzyme, but is sensitive to actinomycin D and cycloheximide. 4. It is suggested that the initial decrease in aminotransferase activity is caused by the release of catecholamines, whereas the subsequent enhancement may be related to the release of glucocorticoids.

Animals↗
PubMed1980

Midline or transverse laparotomy? A random controlled clinical trial. Part I: Influence on healing.

Five hundred and seventy-nine patients undergoing major laparotomy were randomly allocated to have midline or transverse incisions. Transverse incisions took longer to make and caused more bleeding but (in the absence of wound sepsis) no transverse wound burst and there were only 2 incisional hernias. In the midline group, without wound sepsis, there were 2 burst abdomens and 9 incisional hernias. When, however, those patients who suffered wound sepsis were also considered, there were no significant differences between the two groups.

Aged↗
PubMed1980

Midline or transverse laparotomy? A random controlled clinical trial. Part II: Influence on postoperative pulmonary complications.

In a series of 579 patients undergoing major laparotomy, the direction of incision (midline or transverse/oblique muscle-cutting) was decided randomly. The severity of postoperative pulmonary complications was expressed by a scoring system which allowed categorization into mild (score 0-3), moderate (score 4-6) and serious (score 7 or more) complications. The important determinants of high scores were found to be male sex, preoperative pulmonary dysfunction, postoperative ventilatory depression, hypovolaemic and septic shock, inhalation of gastric contents and embolism. In no stratum did the direction of incision have any significant effect.

Aged↗
PubMed1980

Identification of harman in the rat arcuate nucleus.

This communication describes the presence of 1-methyl-beta-carboline (harman) in the hypophysiotropic area of the hypothalamus which incorporates the arcuate nucleus. Diethyl ether extracts of borate-buffered arcuate homogenates were subjected to silica column chromatography and thin-layer chromatography (TLC). Identification of the beta-carboline was accomplished by use of fluorescent spectrometry, gas chromatography (GC), mass spectrometry (MS) and combined gas chromatography-mass spectrometry (GC-MS).

Alkaloids↗
PubMed1980

Enhancement of rat brain metabolism of a tryptophan load by chronic ethanol administration.

We have previously shown that chronic ethanol administration enhances brain 5-hydroxytryptamine synthesis by increasing the availability of circulating tryptophan to the brain secondary to the decreased liver tryptophan pyrrolase activity. We now find that ethanol enhances the brain metabolism of a tryptophan load by the same mechanism. The results are discussed in relation to ethanol preference and the need for further clinical work on the effects of alcoholism on tryptophan metabolism.

Animals↗