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Biomedical subjects

R T Williams

Publications and source records attributed to R T Williams.

At least 55 records · Page 3Linked to original sources
PubMed1982

Increased excretion of urea and N tau -methylhistidine by rats and humans after a bout of exercise.

This study was undertaken to investigate whether an exercise bout increases muscle protein degradation and amino acid catabolism. The excretion of urea and N tau -methylhistidine before and after an exercise bout was determined for both rats and human subjects. The rats ran on a treadmill until they could no longer run. Two groups of human subjects completed strenuous exercise bouts: one group (runners) ran 10-12 miles while the other group (weight lifters) performed a standard power lift routine that lasted approximately 1 h. In rats, urea excretion was elevated for the first 12 h after the exercise bout whereas N tau -methylhistidine excretion was elevated for 48 h following exercise. The increased N tau -methylhistidine excretion after exercise supports previous reports of increased protein degradation in the perfused hindquarter and increased levels of essential amino acids in muscle, liver, and plasma of exercised rats. In human subjects, both running and weight lifting resulted in increased excretion of urea and N tau -methylhistidine. The results of the present study support the hypothesis that muscle protein breakdown and amino acid catabolism are increased by exercise.

Animals↗
PubMed1982

Airway intubator.

Explore the source record for details and available documents.

Intubation, Intratracheal↗
PubMed1981

Influence of exercise on free amino acid concentrations in rat tissues.

Levels of free amino acids in muscle, liver, and plasma were measured in rats that had either swum (1 or 2 h) or run (until exhausted). Exercise lowered alanine levels in all three tissues except for liver of exhausted rats. Exercise decreased the plasma levels of the acidic amino acids and their amides. Glutamate and glutamine levels were depressed in muscle, and the glutamine level was lowered in liver by exercise. Aspartate concentration was lowered by exercise in liver but elevated in muscle. The branched-chain amino acids were generally elevated by exercise as were tyrosine, phenylalanine, methionine, and lysine. Plasma 3-methylhistidine concentration was also elevated by an exercise bout. The changes observed in the amino acid contents of muscle, liver, and plasma are consistent with the increase in protein degradation during exercise that we previously reported. The lowered levels of some amino acids (e.g., alanine, glutamine, glutamate) seem to suggest that amino acid catabolism and/or gluconeogenesis is increased by exercise.

Amino Acids↗
PubMed1979

14C-most-probable-number method for enumeration of active heterotrophic microorganisms in natural waters.

A most-probable-number method using 14C-labeled substrates is described for the enumeration of aquatic populations of heterotrophic microorganisms. Natural populations of microorganisms are inoculated into dilution replicates prepared from the natural water from which the organisms originated. The natural water is supplemented with a 14C-labeled compound added so as to approximate a true environmental concentration. 14CO2 evolved by individual replicates is trapped in NaOH and counted by liquid scintillation techniques for use in scoring replicates as positive or negative. Positives (14CO2 evolution) are easily distinguished from negatives (no 14CO2 evolution). The results from a variety of environments using the 14CO2 procedure agreed well with previously described methods, in most instances. The 14C-most-probable-number method described here reduces handling procedures over previously described most-probable-number procedures using 14C-labeled substrates. It also appears to have advantages over other enumeration methods in its attempt to approximate natural conditions more closely.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1979

Interindividual and interspecies variation in the metabolism of the hallucinogen 4-methoxyamphetamine.

1. The qualitative and quantitative aspects of the urinary elimination of orally administered 4-methoxy[14C]amphetamine have been examined in the rat and guinea-pig and in three volunteer human subjects, to determine interspecies and interindividual variations in disposition of the drug. 2. Both rat and guinea-pig excreted 70--80% of the administered dose(6 mg/kg) in the urine within 24 h, mainly as metabolites. 3. In the guinea-pig, the drug was metabolized by O-demethylation to give 4-hydroxyamphetamine, which was excreted free (4% dose) and conjugated (73%). No other metabolite was detected. 4. The rat metabolizes the drug both by O-dealkylation and by side-chain oxidation, the products being 4-hydroxyamphetamine (5% of dose free and 60% conjugated) and 1-(4'-methoxyphenyl)propan-2-one oxime (5% dose, free and conjugated). 5. In man the drug (dose 5 mg) is metabolized by O-demethylation and by side-chain oxidation. Marked intersubject variations were observed both in the array and quantitative aspects of metabolite excretion. Two subjects excreted mainly 4-hydroxyamphetamine (free and conjugated) together with smaller amounts of 1-(4'-methoxyphenyl)propan-2-one oxime and 4-hydroxynorephedrine. The third subject, however, who was previously known to exhibit a genetically determined defect in drug oxidation, was defective in O-dealkylation of 4-methoxyamphetamine, and the main excretion products were the unchanged drug together with products of side-chain oxidation, namely, 1-(4'-methoxyphenyl)propan-2-one oxime, 1-(4'-methoxyphenyl)propan-2-one and 4-methoxybenzoic acid. 6. Inter-individual differences in oxidative O-demethylation of the drug are discussed in relation to current theories on the aetiology of schizophrenia and reported fatalities arising from abuse of the drug.

Adult↗
PubMed1978

Education as a force for change in mental health settings.

The authors focus on the educational process as a force for bringing about changes in the community or within an agency setting. Four change agent roles--specialist, problem solver, consciousness raiser, and advocate--are identified and described. Attention is then focused on criteria for choosing a change agent role. What kind of change is needed? What is the probability of success using a given role? What are the consequences of functioning in a given role? These are three questions an educational change agent should ask before choosing a role as specialist, problem solver, consciousness raiser or advocate.

Attitude↗
PubMed1978

Transient unilateral blindness following general anaesthesia: case report.

A case is reported of transient unilateral blindness following general anaesthesia with a face mask. The most likely explanation for this is central retinal artery occlusion, either partial or complete, due to excessive pressure from the mask exerted on the globe. This pressure may be increased with the use of neoprene head straps as opposed to the more flexible and elastic rubber straps. Pressure from the strap over the carotid artery may be a factor in reducing the central retinal arterial pressure, thus making it more susceptible to occlusion by mask pressure.

Adult↗
PubMed1978

Taurine conjugates as metabolites of arylacetic acids in the ferret.

1. The pattern of conjugation in the ferret of 8 arylacetic acids and, for comparison, benzoic acid and 4-nitrobenzoic acid was examined. 2. The arylacetic acids, phenylacetic, 4-chloro- and 4-nitro phenylacetic, alpha-methylphenylacetic (hydratropic), 1- and 2-naphthylacetic and indol-3-ylacetic acids, were excreted in the urine as taurine and glycine conjugates. Diphenylacetic acid did not form an amino acid conjugate and was excreted as a glucuronide. 3. The taurine conjugate was the major metabolite of 4-nitrophenylacetic, alpha-methylphenylacetic, 1- and 2-naphthylacetic and indol-3-ylacetic acids, whereas the glycine conjugate was the major metabolite of phenylacetic and 4-chlorophenylacetic acids. Taurine conjugation did not occur with benzoic and 4-nitrobenzoic acids which were excreted as glycine and glucuronic acid conjugates. 4. Phenacetylglutamine and 4-hydroxyphenylacetic acid were minor urinary metabolites of phenylacetic in the ferret. 5. A number of taurine conjugates of aliphatic and aromatic acids were synthesized and their characterization and properties were studied. The role of taurine as an alternative to glycine in the metabolic conjugation of arylacetic acids is discussed.

Acetates↗
PubMed1978

The fate of saccharin impurities: the excretion and metabolism of toluene-2-sulphonamide in man and rat.

Oral doses (20 mg/kg) of [Me-14C]toluene-2-sulphonamide were rapidly eliminated by rats (92% of dose in 24 h). Most of the 14C (88%) was recovered in the urine within 7 days with litte (5%) in the faeces. Larger oral doses (125 and 200 mg/kg) were eliminated more slowly (70 and 43% respectively in 24 h) but the overall distribution of 14C between urine and faeces was unchanged. 2. Low oral doses (0.2--0.4 mg/kg) of [Me-14C]toluene-2-sulphonamide were excreted more slowly in man than in the rat, with about 50% recovered in the urine in 24 h and 80% in 48 h. Negligible 14C (less than 1%) appeared in the faeces. 3. The main metabolites of toluene-2-sulphonamide were 2-sulphamoylbenzyl alcohol and its sulphate and glucuronic acid conjugates (80% of the 14C in the urine of rats and 35% in man) and saccharin (35% in man and 3% in the rat). Other metabolities found in the urine were 2-sulphamoylbenzoic acid (2% in the rat and 4% in man) and N-acetyltoluene-2-sulphonamide (6% in rat and 2% in man) together with unchanged compound (5% in rat and 3% in man).

Animals↗