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Biomedical subjects

D F Smith

Publications and source records attributed to D F Smith.

At least 325 records · Page 18Linked to original sources
PubMed1981

Serum tryptophan levels in alcoholics.

An oral load of L-tryptophan was administered to alcoholics and non-alcoholic control subjects in order to determine whether prolonged ethanol consumption influences serum tryptophan levels. Both samples were taken under fasting conditions and after the load. No differences in fasting serum tryptophan levels were noted. In alcohol addicts and in alcoholics treated with disulfiram (Antabuse) serum tryptophan levels were below normal after the load. No differences were observed in serum tryptophan levels between treated alcoholics not receiving disulfiram and control subjects. The findings suggest that chronic consumption of ethanol-containing beverages can enhance removal of tryptophan from the blood. Explanations to account for this finding are considered.

Adult↗
PubMed1981

Influence of unilateral ECT on tryptophan metabolism in endogenous depression.

Thirteen patients with endogenous depression received an oral load of L-tryptophan (100 mg/kg) before and after a series of unilateral ECT. Age-matched and sex-matched controls also received the tryptophan load twice, at intervals corresponding to those used in the patients. After the loads the level of tryptophan in serum was lower in patients than in control subjects. ECT failed to influence either baseline or postload tryptophan levels. The results are consistent with the notion of disturbances in tryptophan metabolism in patients with endogenous depression, but they fail to clarify the mechanism responsible for the antidepressant effect of ECT.

Adult↗
PubMed1981

Influence of dietary molybdenum on copper metabolism in ponies.

The effects of molybdenum ingestion on copper metabolism were investigated in bile duct-cannulated ponies fed diets containing 1.01, 27.4 and 107.3 ppm molybdenum. Copper metabolism was assessed by examination of 64Cu and stable copper excretion in feces, bile and urine. The addition of molybdenum to the diet decreased copper absorption and retention as a consequence of increased excretion of dietary copper in feces and increased excretion of absorbed copper in bile. Only 5% or less of the absorbed copper was excreted in urine regardless of dietary treatment. Biliary molybdenum excretion was only 0.86 mg per 100 kg of body weight per day even when ponies were fed the highest level of molybdenum. However, increased molybdenum ingestion produced elevations in protein bound copper in bile. Molybdenum was absorbed by ponies but urinary excretion was effective in eliminating most of the element from the body.

Animals↗
PubMed1981

Intrinsic defects in the fetal alcohol syndrome: studies on 76 cases from British Columbia and the Yukon Territory.

Children diagnosed as FAS using standard criteria of maternal alcoholism, poor growth, delayed development and characteristic facial appearance underwent an investigative protocol involving skeletal x-ray surveys, cardiac assessments and intravenous pyelograms (IVP). Significant skeletal findings included cervical spine fusion in 20 of 46 children (43%), x-ray confirmation of microcephaly in 26/49 (53%) and abnormal thoracic cage development in 13/48 (27%). Thirty-nine of 54 children (72%) demonstrated a characteristic tapering of the shaft and occasional associated prominence of the tuft of the distal phalanges Bone age was delayed 2 standard deviations or greater in 14 of 51 children (27%). Cardiac lesions were found in 31 of 76 (41%) and a further 12 (16%) had functional murmurs. Lesions were ventricular septal defect 20 (26%), Tetralogy of Fallot 4 (5.1%), plus a variety of less frequent abnormalities. IVP's were limited to 19 random cases with 5 (26%) showing alterations from the normal. Cervical spine abnormalities of FAS as compared to the Klippel-Feil Syndrome are dissimilar and probably represent a different entity. Hand and lateral cervical spine x-ray studies are felt to be a useful adjunct to the diagnosis and management of the fetal alcohol syndrome.

Abnormalities, Drug-Induced↗
PubMed1981

A method for obtaining abomasal fluid via a rumen fistula.

Abomasal fluid was collected from adult cows using a specially designed tube device. The device was placed in the abomasum through a rumen fistula. A filter on the end of the tube filtered out the larger particles so the liquid could be aspirated up a smaller tube placed inside a larger one. The smaller tube reduced the amount of dead space created by the distance from the abomasum to the rumen fistula.

Abomasum↗
PubMed1980

The distribution of collagen:glucosyltransferase in human blood cells and plasma.

Collagen:glucosyltransferase (UDP-glucose:5-hydroxylysine-collagen glucosyltransferase, EC 2.4.1.66) present in platelets, plasma, granulocytes and lymphocytes has been compared in order to determine whether the platelet enzyme has unique properties or distribution which would support a possible role in platelet-collagen interaction. The enzyme was purified 5400-fold from human plasma and 4400 from human platelets. The two enzymes were similar in terms of Km values for reacting with galactosylhydroxylysine (2.75 mM) and UDPglucose (7.4 microM), optimal Mn2+ concentration (10--15 mM) and pH optimum (7.0). The enzyme was not detectable in red cells. As in platelets, the enzyme was detected in membrane-bound and soluble forms in lymphocytes and granulocytes. Identical mobilities were obtained after elution following polyacrylamide gel electrophoresis of the enzymes from plasma, platelets, granulocytes and lymphocytes. These studies do not support a unique role for the collagen:glucosyltransferase of platelets in platelet-collagen interaction.

Blood Platelets↗
PubMed1980

Antibodies against sialyloligosaccharides coupled to protein.

The beta-(p-aminophenyl)ethylamine derivatives of sialyloligosaccharides can be coupled to proteins via their phenylisothiocyanate intermediates under conditions that preserve labile sugar linkages. Bovine serum albumin containing 10 to 40 mol of oligosaccharides/mol of protein and keyhole limpet hemocyanin containing 1,100 mol of oligosaccharide/mol of protein have been prepared with the following oligosaccharides: Neu-NAc alpha 2-3Gal beta 1-4Glc, NeuNAc alpha 2-6Gal beta 1-4Glc, Neu-NAc alpha 2-6Gal beta 1-4GlcNAc beta 1-4Glc, Gal beta 1-3[Neu-NAc alpha 2-6]GlcNAc beta 1-4Glc, and NeuNAc alpha 2-3Gal- beta 1-3[NeuNAc alpha 2-6]GlcNAc beta 1-4Glc. Rabbits immunized with these synthetic glycoproteins produce antibodies directed against the oligosaccharides. The specificities of these antibodies are determined by comparing inhibitory activities of structurally related oligosaccharides in radioimmunoassay and by double diffusion analysis in agarose gels using oligosaccharide-protein conjugates as precipitating antigens. The antibodies distinguish positional isomers of sialic acid.

Animals↗
PubMed1980

Central and peripheral effects of lithium on conditioned taste aversions in rats.

Central and peripheral injections of LiCl were given to rats to see whether conditioned taste aversions are caused by central or peripheral effects of Li. Rats received an IP injection of either 150 mmol/l LiCl or 150 mmol/l NaCl and a bilateral intracerebroventricular (ICV) injection of either 150 mmol/l LiCl, 150 mmol/l NaCl, or artificial cerebrospinal fluid (CSF) after drinking saccharin solution. Subsequent saccharin intake decreased in rats which received the IP LiCl injection, but failed to depend on which ICV injection had been given. The concentration of Li in bain and CSF was higher 0.5, 1.5, and 4 h after the ICV LiCl injection than after the IP LiCl injection, while the reverse was true for the plasma Li level. It is concluded that conditioned taste aversions are mediated by peripheral effects of Li.

Animals↗
PubMed1980

Tranylcypromine stereoisomers, monoaminergic neurotransmission and behavior. A minireview.

Studies on the effects of the d- and l-stereoisomers of tranylcypromine on locomotor activity, aggressive behavior, hindlimb reflexes, head twitches and behaviors produced by reserpine in rats are reviewed. The d-isomer is found to produce stereotypic behavior and head twitches, to enhance extensor hindlimb reflexes, and to alter effects of reserpine on locomotor activity. The l-isomer is shown to enhance vertical and horizontal locomotor activity and to cause aggressive behavior, but failed to influence hindlimb reflexes, effects of reserpine, or to produce head twitches. Biochemical and pharmacological studies suggest that the d-isomer influences mainly tryptaminergic neurotransmission while the l-isomer affects primarily catecholaminergic neurotransmission. It is concluded that tranylcypromine stereoisomers have stereoselective effects on behavior and monoaminergic neurotransmission. The implications of the findings for the notion that the antidepressant effects of tranylcypromine are due to inhibition of MAO are briefly discussed.

Aggression↗
PubMed1980

Lithium and motor activity of animals: effects and possible mechanism of action.

The effects of lithium on spontaneous activity, exploratory activity, hyperactivity and stereotypy induced by drugs, drug-induced hypoactivity and activity rhythms of animals are reviewed. Attention is given to the rationale for the studies and the relation of research on motor activity of animals to he therapeutic and prophylactic actions of lithium against manic-depressive illness. The most consistent effects of lithium on motor activity of animals are found on exploratory activity, hyperactivity and stereotypy induced by drugs that alter monoaminergic neurotransmission, and rhythmic activity driven by endogenous biological clocks. Suppressant effects of lithium on motor activity appear related to alterations in monoaminergic and cholinergic neurotransmission, to actions of thyroid hormones and to alterations in postsynaptic depolarization. Potentiating effects of lithium on activity seem to be due to alterations in the sensitivity of monoamine receptors. Some suggestions are made concerning further studies of interest to investigate the mechanisms of action of lithium on motor activity.

Amphetamine↗
PubMed1980

Use of Clinitest urine test for indirect estimation of blood glucose levels in the critically ill.

The use of the Clinitest urine glucose test as an indirect way to monitor and control blood glucose levels in critically ill patients was studied. Part 1 of the study was a review of 16 patients records to determine the correlation between 348 paired Clinitest readings and blood glucose levels. Part 2 was a study of six patients from whom a total of 83 arterial blood samples were obtained, each followed 15 minutes later by a urine sample that was tested quantitatively by autoanalyzer and qualitatively by Clinitest. In Part 1, only 43% of the paired readings were within clinically acceptable levels. In Part 2, there was an 11% error rate between quantitative urine glucose values and the corresponding Clinitest results, and the relationship between arterial and urine glucose concentrations was unpredictably variable. The study indicates that both Clinitest error and a variable relationship between arterial and urine glucose concentrations make the use of Clinitest as the sole monitor and basis for controlling blood glucose levels in critically ill patients as unsatisfactory and potentially dangerous procedure.

Adult↗