Biomedical subjects

J D Lenton

Publications and source records attributed to J D Lenton.

4 recordsLinked to original sources

PubMed1993

Assessment of splanchnic blood flow in alcohol and drug abuse using radionuclide angiography.

Computerized radionuclide angiography (RA) is a noninvasive, quantitative, reproducible, and cost-effective method for measuring the portal venous fraction of total hepatic blood flow (represented by the Hepatic Perfusion Index, HPI), and also can be utilized to detect hemodynamic abnormalities in the spleen. A group of 105 men (aged 20-56) were evaluated at the time of admission to the Substance Abuse Program at the Department of Veterans Affairs Medical Center. These patients were classified into three groups: (a) alcohol dependence or abuse (Group A, n = 54); (b) polysubstance abuse without alcohol (Group B, n = 9); and (c) polysubstance abuse with alcohol (Group C, n = 42). Of the respective groups, 69%, 100%, and 79% had abnormal splanchnic flow (liver and/or spleen), whereas only 43%, 78%, and 48% had abnormal liver function tests. This method may be a sensitive, noninvasive detector of early pathophysiological changes in the splanchnic organs of alcohol and drug abusers.

Adult↗

PubMed1989

Elevation of plasma salsolinol sulfate in chronic alcoholics as compared to nonalcoholics.

This report describes a radioenzymatic assay for the measurement of salsolinol and dopamine sulfate levels in plasma. It is based on a sulfatase-catalyzed hydrolysis of the sulfoconjugates followed by catechol-O-methyltransferase and [methyl-3H]-S-adenosylmethionine-catalyzed O-methylation of the resulting free salsolinol and dopamine. Rapid thin-layer chromatographic separation of the formed labeled metabolites attributed to the specificity of the differential enzymatic assay of salsolinol and dopamine. This assay was used to study plasma salsolinol and dopamine levels in a group of adult males (n = 36) serving as controls and a group of hospitalized chronic alcoholics (n = 18). The results (mean and range) of this preliminary study show that alcoholics had significantly (p less than 0.0001) elevated plasma concentration of salsolinol sulfate (497; 50-1331 pg/ml) as compared to controls (93; 0-232 pg/ml). This was accompanied by significant (p less than 0.0003) elevation in plasma levels of dopamine sulfate. Elevation of plasma salsolinol sulfate reported here may be interpreted as a reflection of abnormalities in oxidative metabolism of dopamine, metabolically derived acetaldehyde, and/or biological carbonyls in chronic alcoholics.

Adult↗

PubMed1987

Prevalence of low monoamine oxidase function in alcoholism.

Several studies have found a trend for low platelet monoamine oxidase activity (MAO) in alcoholism but with a great deal of overlap in MAO activity of alcoholics versus controls. The main objective of this study was to carry out a detailed assessment of MAO function that included the measurement of key kinetic parameters (i.e., Km, Vmax) in three groups of male subjects: (a) 51 hospitalized chronic alcoholics, (b) 16 recovering alcoholics with 2-10 years of abstinence, and (c) 21 controls. MAO activity was assayed radiochemically with [14C]tyramine as substrate (43-729 microM). The present study demonstrated that alcoholics had low platelet MAO activity (p less than 0.05). Kinetic analysis revealed a substantial reduction (p less than 0.01) in enzyme Vmax values of chronic and recovering alcoholics. Greater than 95% of the alcoholics had Vmax values lower than the smallest value of control subjects. Moreover, 100% of the alcoholics in both groups exhibited exceedingly low Vmax values that were below the 25th percentile of controls. In summary, results of MAO Vmax determinations provided us with a better separation of the alcoholics from controls. Measurements of platelet MAO function that include enzyme Vmax may provide us a reliable biochemical marker for alcoholism.

Adult↗

PubMed1984

Propoxyphene dependence: problems in management.

Propoxyphene dependence presents a difficult treatment problem: the patients' subjective discomfort and concomitant craving during gradual withdrawal of the drug is more intense and more poorly tolerated than that observed with other narcotic analgesic agents. Of the six patients we describe, only one has achieved successful detoxification.

Adolescent↗