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Biomedical subjects

J Williams

Publications and source records attributed to J Williams.

At least 1,099 records · Page 61Linked to original sources
PubMed1978

The learning of radiological anatomy by medical students.

Teaching radiographic anatomy to pre-clinical medical students is important as it relates anatomical studies to clinical medicine and the same time prepares them for the radiology they will encounter in their clinical years. A programme is described in which radiographic anatomy is comprehensively covered without proving too great a commitment to clinical radiologists. The programmes consist of exhibits of X-rays in the dissecting room, slide-lecture demonstrations and a permanent museum of radiological anatomy. This programme has worked well and there has been a very favourable student response.

Anatomy↗
PubMed1978

The effect of baclofen on alpha-flupenthixol-induced catalepsy in the rat.

1 alpha-Flupenthixol (alpha-FPT; 0.2 mg/kg i.p.) when administered to rats produced catalepsy. 2 Baclofen (10 mg/kg i.p.) given 30 min after alpha-FPT had a biphasic effect on the catalepsy. Initially there was a potentiation of the effect, followed by a significant attenuation of the degree of catalepsy. 3 Possible mechanisms of action are discussed.

Aminobutyrates↗
PubMed1978

Assembly intermediates among adenovirus type 5 temperature-sensitive mutants.

Temperature-sensitive mutants from three different complementation groups, ts5, ts19, and 6s58, have been shown to accumulate assembly intermediates at the restrictive temperature. The polypeptide composition of these intermediates is similar to that of the wild type, including the precursor polypeptides pVI, pVII, and pVIII. ts5 and ts19 also contained cleaved precursors, indicating assembly into defective virions. The increase of infectious virus after temperature shift-down of ts19 and ts58 was rapid when compared with that of ts24, which does not accumulate intermediates, suggesting that intermediates formed at nonpermissive temperature may be processed to mature virus. However, shift-down experiments reveal that only a fraction of the intermediates are utilized for virus assembly and that degradation of intermediates occurs at the restrictive temperature.

Adenoviruses, Human↗
PubMed1978

Analytical performance and comparability of the determination of triglycerides by 12 Lipid Research Clinic laboratories.

Twelve Lipid Research Clinic laboratories performed automated fluorometric triglyceride analyses on four control serum pools of known concentration by a modified Hantzsch reaction. The analyses were done during a two-year period, with use of common standards, methodology, and quality-control procedures. Estimates of analytical bias, variability, and short- and long-term trends for each instrument and for the entire group of LRC instruments are presented. High accuracy, precision, and interlaboratory comparability were achieved through rigorous standardization and control of the entire analytical procedure. Individual instrument biases varied from an average of 4.9% below to 1.0% above reference values. Between-run variability was often less than within-run variability and interlaboratory variation was substantially less than intralaboratory variation. The total standard deviation for all instruments ranged from 37 to 63 mg/liter. Only 5 to 14% of this variation was due to differences among instruments. The among-instruments standard deviation ranged from 12 to 17 mg/liter; the between-run, within-instrument standard deviation ranged from 29 to 46 mg/liter, and within-run standard deviation from 27 to 40 mg/liter. The significance of the results for long-term collaborative studies is discussed.

Analysis of Variance↗
PubMed1978

Nitrogen elimination during steady-state hyperbaric exposures.

Nitrogen elimination was measured in six divers during steady-state exposures in an oxygen-nitrogen atmosphere at 1, 2, and 3 ATA using both oxy-helium and pure O2 as washout gases. This was accomplished by using mass spectrometry to measure the expired N2 concentration breath-by-breath over periods of 120 min in all experimental conditions except for O2 breathing at 3 ATA, which was limited to 30-min periods. In all cases the area under the elimination curve increased with pressure. Total area under the curve was also greater when breathing O2 than when breathing oxy-helium, but this difference decreased with depth and washout time. Nitrogen elimination on a semilogarithmic plot falls rapidly during the first four minutes and then shows a slow linear fall for the remainder of the measurement period. Effective elimination of nitrogen decreased with depth and oxygen was more effective than oxy-helium in washing out nitrogen at all depths studied. Possible causes of the different variations noted in the washout curves during the experiment are discussed.

Atmospheric Pressure↗
PubMed1977

Purification and properties of an alpha-D-galactoside galactohydrolase from the seeds of Trifolium repens (white clover).

Five alpha-D-galactosidases (alpha-D-galactoside galactohydrolase; EC 3.2.1.22) have been identified by chromatography and polyacrylamide-disc-gel electrophoresis in the germinated seeds of Trifolium repens (white clover). alpha-Galactosidase I has been purified to homogeneity with an approx. 2000-fold increase in specific activity. The enzyme was purified by a procedure which included precipitation by dialysis against citrate/phosphate buffer, pH3.5; (NH4)2SO4 precipitation; hydroxyapatite, DEAE-cellulose and ECTEOLA-cellulose column chromatography. Each stage of purification was controlled by polyacrylamide-disc-gel electrophoresis; the purified enzyme showed a single protein band that corresponded to the alpha-D-galactosidic activity. The pH optimum was found to be between pH 3.8 and 4.2; the enzyme is highly thermolabile. Hydrolysis of oligosaccharides and galactomannans has been examined, and it has been found that alpha-galactosidase I exhibits two enzymic activities, namely alpha-D-galactoside galactohydrolase and galactosyltransferase. By the polyacrylamide-gel-electrophoresis method of Hendrick & Smith (1968), and by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, the mol.wt. has been estimated to be 43 000 and 41 000 respectively. These results indicate that alpha-galactosidase I is a monomeric protein and that both enzymic activities associated with the enzyme reside on the same polypeptide chain.

Chromatography↗