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Biomedical subjects

H Williams

Publications and source records attributed to H Williams.

At least 199 records · Page 11Linked to original sources
PubMed1987

Exercise-induced glycogen utilization by the respiratory muscles.

Some controversy exists in the literature as to whether or not diaphragmatic glycogen is utilized during exercise. In this study male Sprague-Dawley rats were used to determine whether prolonged treadmill exercise would result in a significant reduction of glycogen concentration in the respiratory muscles. Untrained rats were run to exhaustion at a speed of 24 m/min, up a 10% grade. Run time averaged 48:30 min. After exercise a significant reduction in glycogen was observed in the diaphragm (43% of control), intercostals (43%), heart (39%), and plantaris (76%). In the diaphragm a significant reduction was shown in both types I and II fibers using the periodic acid-Schiff (PAS) stain for glycogen. These findings show that muscles with vastly different aerobic capacities utilize endogenous glycogen during moderately intense submaximal endurance exercise and that the costal diaphragm muscle is not an exception as has recently been suggested.

Animals↗
PubMed1986

Further investigations of a hydatid focus in North-West Scotland.

A serological survey carried out on 1379 school-children from Skye and Mallaig in the N.W. of Scotland failed to show evidence of subclinical cases of hydatidosis. There appeared to be a relatively low level of exposure to the parasite, as judged by ELISA and IHA tests. Thirty-one children reacted positively in the ELISA; only one child had a transient positive result in the IHA test. Surveillance of these children will be continued for the present but the duration required is uncertain. The local population appeared to be well aware of the mode of spread of the parasite and the methods for its control.

Animals↗
PubMed1986

Evaluation of biopsy techniques for androgen receptor assay in human prostatic tissue.

Androgen receptors were assayed in nuclei prepared from human benign hypertrophic prostate tissue obtained at retropubic prostatectomy by transurethral resection (TURP) and by cold punch resection. Androgen receptor was not detected in 70% of the transurethrally resected samples, and in those cases where receptors were observed they showed no correlation with enucleated samples. However, androgen receptors were detected in all cold punch resected samples and enucleated tissue with similar concentrations evident in samples from the same gland. These results suggest that prostate specimens collected by TURP are not suitable for androgen receptor analysis, whereas the technique of cold punch resection yields prostate samples that are more reliable for a correct evaluation of androgen receptor content.

Aged↗
PubMed1986

The use of flanking markers in prediction for Duchenne muscular dystrophy.

Seventy three sisters of boys with Duchenne muscular dystrophy and their families were studied using up to seven deoxyribonucleic acid (DNA) probes linked to the gene on the short arm of the X chromosome. Fifty three (73%) were informative for flanking markers, a further 18 (24%) being informative for a single marker only. Predictions based on pedigree structure and creatine kinase information from the individuals and their female relatives gave more than half (55%) of the sisters a risk for being a carrier of below 10% or above 90%. The addition of information derived from the inheritance of flanking DNA markers, where they exist, improves the situation so that many more sisters (77%) can be allocated into either high or low risk categories.

Adolescent↗
PubMed1986

A computer programme for estimation of genetic risk in X linked disorders, combining pedigree and DNA probe data with other conditional information.

A computer programme is presented for calculating the recurrence risk in X linked disorders, combining pedigree and DNA probe data with other conditional information such as carrier detection tests. The methods of computation are shown in the given examples. The programme can be used with either a single DNA probe or two 'flanking' DNA probes for both familial and isolated case pedigrees. For isolated case families the mutation rate at the disease locus can be taken into account in conjunction with the DNA probe data.

DNA↗
PubMed1986

Localisation of the gene for Emery-Dreifuss muscular dystrophy to the distal long arm of the X chromosome.

The linkage relationships of the gene for Emery-Dreifuss muscular dystrophy have been analysed in a large American kindred using DNA probes from different regions of the X chromosome. Close linkage was found with the locus for factor VIII, with no recombinants in 12 opportunities (maximum lod score 4.3), and with locus DXS15 (two recombinants in 17 opportunities, maximum lod score 2.9 at 0 = 10 cM). No linkage was found with probes pERT87 and 754, which are closely linked to Duchenne and Becker muscular dystrophies at Xp21. These results confirm a separate localisation on the distal part of the long arm at q27-28 for Emery-Dreifuss muscular dystrophy and should provide the basis for prenatal diagnosis and improved carrier detection in this disorder if the linkage is confirmed to be close.

Chromosome Mapping↗
PubMed1986

Twice daily versus four times daily treatment with beclomethasone dipropionate in the control of mild childhood asthma.

The effects of controlling childhood asthma of the same daily dose (400 micrograms) of beclomethasone dipropionate, given in two or four equal divided doses from a metered aerosol, were compared in a double blind crossover study. Thirty one children aged 6-14 years completed the study. They had previously been shown to need beclomethasone by showing either symptoms or reduced peak flow when the treatment was withdrawn. They recorded their daytime and night time symptoms on a visual analogue scale and their morning and evening peak expiratory flow (PEF), and recorded their symptomatic use of bronchodilator aerosols. Spirometry was performed at the end of each treatment period. Control of asthma was good on both regimens. There were small differences in both objective and subjective measurements in favour of the four times daily regimen, but none reached statistical significance, apart from patients' assessment of daytime wheeze (p less than 0.05). In particular, the differences in the results of lung function tests were very small. Compliance was better for morning and evening doses. These results suggest that beclomethasone given as 200 micrograms twice daily is effective in controlling mild childhood asthma. It may be preferable to 100 micrograms four times daily because of better compliance and because it is unnecessary to take medication to school.

Adolescent↗
PubMed1986

Hemodynamic predictors of outcome in patients undergoing valve replacement.

The afterload-corrected end-systolic volume index (ratio of end-systolic stress to end-systolic volume index [ESS/ESVI]) was previously useful in predicting outcome in patients with mitral regurgitation undergoing valve replacement. Therefore we tested ESS/ESVI together with standard hemodynamic variables as possible predictors of outcome in 39 patients with various valvular lesions who underwent valve replacement. Thirteen patients had preoperative mitral regurgitation, 16 had aortic stenosis, nine had aortic regurgitation, and one had mitral stenosis. Twenty-seven patients (group S) had a satisfactory outcome as defined by a return to NYHA class I or II together with a normal postoperative ejection fraction. Twelve patients who died, remained in class III or IV, or had a subnormal postoperative ejection fraction were deemed to have an unsatisfactory result (group U). Mean right atrial pressure, pulmonary arterial pressure, pulmonary capillary wedge pressure, end-diastolic volume index, end-systolic volume index (ESVI), and end-systolic wall stress were all greater in group U, whereas ESS/ESVI and ejection fraction were lower in group U. When these and other factors were submitted to stepwise discriminant multivariate analysis, ESS/ESVI and ESVI were the only independent predictors of outcome. However, when patients with mitral regurgitation (who might have biased the study) were excluded, discriminant analysis showed ESVI as the only independent predictive variable. We conclude that end-systolic indicators of ventricular function are superior to other standard hemodynamic variables in predicting outcome of valve replacement.

Aortic Valve↗
PubMed1986

The effects of various substituted hydrocarbons on two heme synthesis regulatory enzymes.

Benzene and some of its derivatives have been shown to cause alterations in heme and globin synthesis. Structure/activity relationships of the effects of substituted aromatic hydrocarbons on delta-aminolevulinic acid synthetase (ALAS) and ferrochelatase (FC) activities were studied. These enzyme systems were studied because they were regulatory and represented the initial and final enzymes in the biosynthesis of heme. Normal values for rat liver ALAS were 250-350 microM ALA/g protein/30 min, mean 293 microM/g +/- 44 (SD). Normal values for FC were 12-40 microM heme/g protein/45 min, mean 18 microM/g +/- 0.7 (SD). Nitrosonaphtholics inhibited ALAS activity an average of 49%; nitrosobenzenes, 48%; chloronitrobenzoic acids, 39%; phenol, 37%; nitrophenols, 22%; aminophenols, 16% and chlorophenols, 5%. Certain compounds inhibited FC activity: nitrosonaphtholics, 99%; chlorophenols, 56% and nitrosobenzenes, 3%. Some compounds that significantly inhibited ALAS activity enhanced FC activity, e.g. phenolic compounds and chloronitrobenzoic acids. The inhibitory effect may reflect a blockage of the active site of the enzymes and/or binding of a required substrate. The enhancing effect may be due to making the binding site of the heme pocket of the porphyrin more accessible to iron. These techniques may prove useful for assessing toxicity of pollutants in animal species.

5-Aminolevulinate Synthetase↗