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Biomedical subjects

C Williams

Publications and source records attributed to C Williams.

At least 307 records · Page 17Linked to original sources
PubMed1996

Carbohydrate ingestion and single muscle fiber glycogen metabolism during prolonged running in men.

The aim of this study was to examine the effect of carbohydrate (CHO) ingestion on glycogen degradation in type I and type II muscle fibers during prolonged running by using a quantitative biochemical method. To this end, eight male subjects ran at 70% maximal oxygen uptake to exhaustion on a motorized treadmill on two occasions, 1 wk apart. On each occasion, the subjects ingested 8 ml/kg body wt of either placebo (Pl) or a 5.5% CHO-electrolyte solution (CHO-E) immediately before the start of the run and 2 ml/kg body wt every 20 min thereafter. Needle biopsy samples were obtained from the vastus lateralis muscle before and after each trial and also at the time coinciding with Pl exhaustion in the CHO-E trial. Running time to exhaustion was longer (P < 0.01) in the CHO-E trial compared with the Pl trial (132.4 +/- 12.3 and 104.3 +/- 8.6 min, respectively). A 25% reduction in glycogen utilization in type I fibers only was observed in the CHO-E trial compared with the Pl trial (215.2 +/- 27.5 vs. 285.4 +/- 30.1 mmol/kg dry wt; P < 0.01). Furthermore, in the CHO-E trial, in contrast to the Pl trial, both muscle ATP and phosphocreatine concentrations were well maintained throughout exercise. Therefore, because in both the Pl and CHO-E trials the type I fibers were glycogen depleted at the point of exhaustion (31.6 +/- 10.3 and 28.1 +/- 7.1 mmol/kg dry wt, respectively), it is proposed that CHO ingestion improved endurance capacity by contributing to oxidative ATP production specifically in type I fibers and by doing so delayed the development of glycogen depletion in this fiber type.

Adult↗
PubMed1996

Epidermal growth factor delays gastric emptying and small intestinal transit in suckling rats.

Suckling (12-d-old) rats that were fasted for 15 h received epidermal growth factor (EGF) s.c. (0.5 and 1.0 microgram per rat, i.e. approximately 2 and 4 micrograms/100 g of body weight), together with motility markers 51Cr-EDTA or Poly R-478, and were killed 45 min later. Counts were measured separately in the stomach and the small intestine, which was divided into 12 segments. Administration of EGF delayed gastric emptying. In controls, the stomach contained 26.1 +/- 1.6% (mean +/- SEM); in EGF-treated rats the stomach contained 75.9 +/- 10.2% and 75.7 +/- 2.5% of the total 51Cr-EDTA counts given. EGF had the maximum effect (1.0 microgram) when given simultaneously with 51Cr-EDTA. Significant, but lower, effects of EGF were seen with the administration of EGF preceded by 10 min or followed by 10 and 20 min with the administration of 51Cr-EDTA (65.8 +/- 5.8%, 60.0 +/- 6.4%, and 54.1 +/- 4.2%, respectively). Small intestinal transit was also delayed. Administration of anti-EGF antiserum did not affect gastric emptying, but accelerated small intestinal transit as determined 30 min after administration of 51Cr-EDTA. These studies are the first to demonstrate the effect of EGF on gastrointestinal motility in vivo in suckling mammals.

Animals↗
PubMed1996

Methodology for a randomised controlled trial of preschool vision screening. A new approach with the 'ALSPAC' project.

We present the methodology of a population-based Randomised Controlled Trial, comparing an intensive programme of primary preschool vision screening by orthoptists with the usual non-specialist screening. The aims of the trial are to compare the effectiveness and costs of intensive orthoptic screening with non-specialist measures. The orthoptic screening programme will be evaluated both as a composite package and in terms of the screening value of the individual tests at specific ages. This trial is nested within a large population-based longitudinal study. Additional demographic and developmental data on the children in the trial are therefore available. The results of the trial will be used to help clarify which methods of preschool ophthalmic population screening are best in terms of disease detection and cost efficiency.

Amblyopia↗
PubMed1996

Nocturnal enuresis and the use of desmopressin: is it helpful?

We assessed the outcome of the use of an enuretic alarm and desmopressin according to conventional guidelines and investigated the reasons for resistance to desmopressin. Children were given a 4 month course using an enuretic alarm if they had not previously used one; 12 out of 21 were dry (57%) after 4 months and one relapsed 1 month later. Those who had previously failed with an alarm or were considered poorly motivated to use it, were given a 4 month course of intranasal desmopressin. Of these 26 children, 10 (38%) were dry at the end of 4 months but only two (7%) remained dry after this was withdrawn. After the initial treatment with alarm or desmopressin, 27 children were still enuretic and attending the clinic. They were shown how to use the alarm and eight also used the dry bed training technique: 15 had become dry after a further 6 months. Of the 12 children who made no response to intranasal desmopressin, nine were given this medication under supervision in hospital; seven of these children still wet the bed despite producing small amounts of concentrated urine overnight. They also had small measured diurnal bladder capacities. We conclude that if a 4 month course with an enuretic alarm is unsuccessful, rather than using desmopressin, the alarm should be continued with relearning and consideration given to additional use of the dry bed training technique. The major factor causing nocturnal enuresis in children is likely to be a small nocturnal bladder capacity.

Administration, Intranasal↗
PubMed1996

Food preferences among individuals with and without Prader-Willi syndrome.

Eleven individuals with Prader-Willi syndrome and 10 control subjects who had mental retardation due to other causes (with and without overeating histories) participated in two experiments on food preferences. They gave preference rankings for various foods, then chose between a small amount of their most preferred food and an alternative choice of a larger amount of mixed-preference foods (Experiment 1) or an alternative choice of a larger amount of their least preferred food (Experiment 2). Unlike overweight-prone control subjects who selected sweet food over a larger quantity of unpreferred food, subjects with Prader-Willi syndrome selected preferred items only over least-preferred items (Experiment 2) but not over mixed-preference items (Experiment 1). Implications for treatment were discussed.

Feeding Behavior↗
PubMed1996

The response of goat brain cells to infection by caprine arthritis-encephalitis virus.

Caprine arthritis-encephalitis virus is a lentivirus of goats causing encephalomyelopathy acutely in young goats and occasionally in late stages of chronically infected adult goats. To determine the specific brain cells infected by the virus and the response of other cell types, goat cerebrum explant cultures prepared from newborn goat kids were infected by virus application. Infection of brain cultures was also possible by coculture with virus-infected macrophages. Predominantly, microglia cells were specifically infected by the virus, resulting in death of more than 50% of the cells within 2 weeks of infection. Infected cells enlarged and formed multinucleated giant cells. Infection of oligodendrocytes was observed, but infrequently. Astrocytes were not infected. Proviral deoxyribonucleic acid (DNA) was detected in infected cultures by amplification of a 490 base-pair fragment of the viral gag gene by the polymerase chain reaction (PCR) technique. Virus budding from plasma membrane of infected microglia cells was demonstrated by transmission electron microscopy. The supernatant of infected brain cells induced cytopathic effect when applied to indicator cells. These observations suggest productive infection of brain cultures. Virus infection of neurons was not observed. Culture of neurons in virus-free supernatant of CAEV-infected microglia or mixed glia culture resulted in death of 50% of the neurons in 11 days, suggesting the production of neurotoxic substances by the virus-infected glial cells.

Animals↗
PubMed1995

Using a mixture model to predict the occurrence of diabetic retinopathy.

Diabetes mellitus is a common condition which has several serious complications associated with it. In this paper a mixture model, based on one previously used to predict the onset of AIDS, is used to predict the onset of one of these complications, diabetic retinopathy, the major cause of adult blindness in the U.K. This model differs from the previous AIDS model by introducing covariates into the model and using a wider choice of mixture distributions. The fit and distributional assumptions of the model are then discussed for this example. The model is fitted to the data by maximum likelihood. It is important that the training set contains balanced numbers of individuals with and without retinopathy.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Association of anophthalmia and esophageal atresia.

We report on a boy and a girl with bilateral anophthalmia and proximal esophageal atresia. In addition to vestigial optic nerves and chiasma, MRI studies showed other central nervous system abnormalities; one had ectopic tissue in the hypothalamic region, and the other hand generalized ventriculomegaly associated with atrophy. Two other cases, both males, have been reported with anophthalmia and esophageal atresia as their only malformations. These 4 cases are reviewed in light of recent advances in the understanding of ocular embryogenesis and of the midbrain as a development field. Concurrence of these defects appears to be non-random.

Anophthalmos↗
PubMed1995

Carbohydrate ingestion and glycogen utilization in different muscle fibre types in man.

1. The effect of carbohydrate (CHO) ingestion on muscle glycogen utilization during exercise was examined on seven male subjects completing two 60 min treadmill runs at 70% maximum oxygen uptake (VO2,max), 1 week apart. On each occasion the subjects consumed either water or a 5.5% CHO-electrolyte solution immediately before and during exercise. Muscle samples were obtained from the vastus lateralis by needle biopsy before and immediately after exercise. Venous blood samples were also collected from an ante-cubital vein at rest and at 10, 20, 40 and 60 min into the run. 2. Higher blood glucose concentrations (P < 0.01) were observed throughout the run during the CHO trial compared with the water trial. Serum insulin concentration was only higher after 20 min of exercise (P < 0.01). 3. A 28% reduction in mixed glycogen utilization was observed as a result of CHO ingestion when compared with water ingestion (108.7 +/- 16.3 vs. 150.9 +/- 19.9 mmol (kg dry matter)-1, respectively; P < 0.01). 4. The ingestion of the CHO solution resulted in sparing of glycogen in type I (slow twitch) fibres only (38 +/- 7% degradation of glycogen as opposed to 66 +/- 3% during the water trial; P = 0.01).

Adult↗
PubMed1995

Healthy eating: clarifying advice about fruit and vegetables.

Consumers need health information which is clear and unambiguous. Advice to "eat more fruit and vegetables" gives consumers no guidance on the quantities involved. Popular advice is to eat "five portions a day." This paper provides a rationale for determining which foods are included within this advice--for example, processed foods such as baked beans are but potatoes and nuts should not be. It also describes how much of the most commonly consumed fruit and vegetables constitutes a "portion." A bowlful of salad, for example, is needed to make up a portion but an apple or banana on its own will count.

Diet↗