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Biomedical subjects

D F Smith

Publications and source records attributed to D F Smith.

At least 379 records · Page 21Linked to original sources
PubMed1976

Comparative chemical analyses of the alloantigenic fragments of HL-A antigens.

Papain-solubilized HL-A antigens have been shown to contain two polypeptide fragments: beta2-micro-globulin with a molecular weight of approximately 12,000 and a larger fragment with a molecular weight of about 34,000. The large fragments isolated from two HL-A preparations carrying different specificities appeared homogeneous both by immunoelectrophoresis and sodium dodecyl sulfate-acrylamide electrophoresis. Both HL-A antigen preparations contained the same NH2-terminal (glycine) and the same COOH-terminal residue (serine). The carbohydrate content of the large fragment was 12.9%, making the carbohydrate-free molecular weight approximately 30,000. Small but significant differences have been found in the amino acid compositions and tryptic peptide maps of the two large fragments containing different specificities.

Amino Acids↗
PubMed1976

The role of alpha- and beta-adrenergic effects in the action of adrenaline on renal lithium elimination in adrenalectomized rats.

Repeated s.c. injections of L-adrenaline (4 X 0.5 mg/kg body weight) increased the urinary clearance of lithium in intact rats and in adrenalectomized animals. Adrenaline also increased the fractional excretion of lithium in adrenalectomized rats; an effect that was prevented by repeated s.c. injections of the alpha-adrenergic blocking agent phentolamine (4 X 1 mg/kg body weight). When administered alone, propranolol and phentolamine decreased the urinary clearance of lithium in adrenalectomized rats. The drug-induced changes in the urinary clearance of lithium were not directly related to the effects of the drugs on the urinary elimination of sodium, potassium, creatine and water. The results suggest that the action of adrenaline on renal lithium elimination in adrenalectomized rats might be mediated by alpha-adrenergic receptors.

Adrenal Glands↗
PubMed1976

Locomotor activity and plasma, red blood cell and cerebral cortex lithium concentration in inbred mice given lithium carbonate.

Inbred male C57 BALB, C3H and DBA mice received lithium carbonate in their food for 3 weeks. Their locomotor activity was measured by photocells and the concentration of lithium in their plasma, red blood cells and cerebral cortex was determined. The susceptibility of the inbred strains of mice to the activity-suppressant effect of lithium was C3H greater than DBA greater than BALB = C57. The concentration of lithium in plasma varied between 0.85-1.02 mEq 1. No relationship was found between lithium's pharmacokinetics and its effects on activity. The findings are consistent with the notion that genetic factors can influence the effects of lithium on behavior, but they do not support the hypothesis that genetic determination of lithium's uptake into cells is responsible for these effects.

Animals↗
PubMed1976

Effects of alpha methyltyrosine and parachlorophenylalanine on open field behavior in rats given tranylcypromine stereoisomers and lithium carbonate.

Parachlorophenylalanine (PCPA) and alpha methyltyrosine (AMT) were used to study the roles of serotonin and catecholamines in hyperactivity produced by the stereoisomers of Tranylcypromine (d-Tc and 1-Tc) in male Wistar rats fed a normal diet (control groups) or a diet containing lithium carbonate (lithium groups). Components of locomotor activity were measured in an open field. Lithium decreased ambulation. d-Tc increased ambulation and caused jerky side-to-side movements. PCPA and AMT prevented the effects of d-Tc on ambulation while only PCPA prevented the effects of d-Tc on movement. 1-Tc increased ambulation. The effects of 1-Tc on ambulation were potentiated by PCPA and prevented by AMT. Rearing was increased by 1-Tc and d-Tc in rats given lithium. PCPA and AMT prevented the effects of 1-Tc and d-Tc on rearing in lithium groups. The findings suggest that the roles of serotoninergic and catecholaminergic mechanisms differ for components of open field behavior in control rats and rats given lithium.

Animals↗
PubMed1976

Effect of posture on renal lithium clearance.

1. Renal lithium clearance in healthy men was elevated while the subject was reclining, decreased upon standing and increased upon lying down during 45-60 min tests. 2. Parallel changes in renal clearance of creatinine, sodium and potassium, and urine flow rate occurred in response to the changes in posture. 3. The findings demonstrate for the first time that posture is a factor that can influence lithium excretion. Control of posture during lithium excretion tests is recommended.

Adult↗
PubMed1976

Lithium orotate, carbonate and chloride: pharmacokinetics, polyuria in rats.

1 The pharmacokinetics of the lithium ion administered as lithium orotate were studied in rats. Parallel studies were carried out with lithium carbonate and lithium chloride. 2 No differences in the uptake, distribution and excretion of the lithium ion were observed between lithium orotate, lithium carbonate and lithium chloride after single intraperitoneal, subcutaneous or intragastric injections (0.5-1.0 mEq lithium/kg) or after administration of the lithium salts for 20 days in the food. 3 The findings oppose the notion that the pharmacokinetics of the lithium ion given as lithium orotate differ from lithium chloride or lithium carbonate. 4 Polyuria and polydipsia developed more slowly in rats given lithium orotate than in those given lithium carbonate or lithium chloride, perhaps due to an effect of the orotate anion.

Animals↗
PubMed1976

Constant release of photosynthate from marine phytoplankton.

The release rate of dissolved organic carbon (DOC) by unialgal cultures and natural phytoplankton assemblages was constant over a wide range of dissolved inorganic carbon concentrations. DOC release was not proportional to the particulate organic carbon production rate. We postulate that intracellular DOC, fated for release, exists either as a separate pool from that leading to particulate organic carbon production or that there is active metabolic control on one portion of a common pool.

Animals↗
PubMed1976

Responses of young calves to low doses of lead.

Twenty calves, week-old male Holsteins, 42.8 kg body weight, were assigned to four treatments by oral dose 0, 1.5, 3.0, and 6.0 mg lead carbonate/kg body weight given three times weekly until calf fetal hemoglobin had been converted to 100% adult hemoglobin for 2 consecutive wk. Analyses were for the first 7 wk when data were complete. Variables included lead in blood, body weight changes, erythrocyte delta-aminolevulinic acid dehydrase activity, packed cell volume, hemoglobin, conversion of fetal to adult hemoglobin, and erythrocyte 2,3-diphosphoglyceric acid. Early changes due to lead treatment were inhibition of delta-aminolevulinic acid dehydrase at all doses and increased loss of hemoglobin at 3.0 and 6.0 mg doses. Growth rate was not impaired seriously by lead treatment. The 2,3-diphosphoglyceric acid in erythrocytes reached peak value at 3 to 4 wk of age and then decreased with age, but 2,3-diphosphoglyceric acid of the treated calves was not changed by the low lead dosing. Low lead dosing will induce early metabolic changes in the young calf prior to inhibition of growth.

Age Factors↗
PubMed1975

Endometriosis.

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Adult↗
PubMed1975

Biogenic amines and the effect of short term lithium administration on open field activity in rats.

Experiments were performed to examine whether the effects of short-term lithium administration on cerebral biogenic amine metabolism might be related to its action on open field activity. Rats received intragastric injections of lithium chloride (1.5 mEq/kg) twice daily for 5 days. This lead to a decrease in exploratory behavior in the open field. Administration of imipramine, which blocks the efffects of short-term lithium administration on norepinephrine turnover and uptake in the brain, failed to influence the effect of lithium on exploratory activity. Parachlorophenylalanine, which inhibits cerebral serotonin synthesis and depletes brain catecholamines, prevented the behavioral effect of lithium. Injection of pargyline, which inhibits cerebral monoamine oxidase activity, counteracted the effect of lithium on exploratory behavior and also influenced the emotionality of the animals in the open field. The findings are consistent with the hypothesis that cerebral monoamine levels and monoamine oxidase activity play a role in the effect of short-term lithium administration on open field activity in rats.

Animals↗