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Biomedical subjects

C E Bayliss

Publications and source records attributed to C E Bayliss.

At least 19 recordsLinked to original sources
PubMed1987

Comparison of populations of human faecal bacteria before and after in vitro incubation with plant cell wall substrates.

Human faecal slurries were incubated anaerobically with larchwood xylan, oat spelt xylan, wheat bran, apple cell walls or sugar beet pulp as sole carbon sources. The populations which developed during incubation were different from the inoculum, the most marked changes being an increase in the number of Bacteroides species and a decrease in the number of Fusobacterium species for all carbon sources tested. With a water-soluble preparation of larchwood xylan the population was dominated by species able to ferment this substrate, in contrast to the population which developed with the insoluble substrates. The ability to use one plant cell wall substrate appeared to be related to the ability to use others. Strains capable of using plant cell wall substrates included Bacteroides spp., Clostridium clostridiiforme, Bifidobacterium longum, Fusobacterium spp. and Escherichia coli. When incubation with two contrasting substrates (bran and larchwood xylan) was replicated, the populations which developed were reproducibly different from the inoculum and from each other.

Bacteroides↗
PubMed1986

A change in human faecal flora in response to inclusion of gum arabic in the diet.

1. Gum arabic is a water-soluble polysaccharide resistant to human gut enzymes and thus can be described as dietary fibre. 2. Using a most-probable-number technique, estimates were made of total anaerobes and of gum-arabic fermenters in the faeces of a volunteer during a control period and during addition of 10 g gum arabic/d to the diet. Using an enrichment technique, the principal bacteria able to utilize gum arabic as the only carbohydrate source were isolated and characterized. 3. Faecal samples were analysed for undegraded gum arabic and, following acid-hydrolysis, for total sugars. 4. The proportion of the faecal flora able to degrade the gum arabic polymer rose from an initial level of 6.5% to more than 50% during gum-arabic ingestion, and subsequently returned to the control level after ingestion ceased. The principal gum-arabic fermenters were species of Bacteroides and Bifidobacterium. 5. Undegraded gum arabic was not detected in any faecal sample nor were there significant differences in the level of total sugars in acid-hydrolysed faeces between gum arabic and control periods. 6. The results presented indicate a direct and rapid change in faecal flora in response to a specific change in the diet of a human volunteer.

Adult↗
PubMed1986

Intestinal microflora, morphology and enzyme activity in zinc-deficient and Zn-supplemented rats.

1. Immature, male Wistar rats were given a low-zinc diet (2 mg/kg) for 22-24 d. Control groups received a similar diet supplemented with 58 mg Zn/kg either ad lib., or in amounts matched to the consumption of the Zn-deficient group. Food consumption, rate of growth and food conversion efficiency were markedly lower in the Zn-deficient group of rats compared with controls. Appetite, growth rate and food utilization improved dramatically over a subsequent 4 d period of Zn supplementation. 2. Morphological examination of samples of jejunum and ileum confirmed that Zn deficiency in the rat is accompanied by a reduction in villous dimensions and increase in villous density. After a short period of Zn supplementation, villous density and the basal width and maximum height of individual villi in the jejunum returned to normal. Similar changes occurred in the ileum but to a lesser extent. 3. Mucosal alkaline phosphatase (EC 3.1.3.1) activity was significantly lower in the small intestine of Zn-deficient rats compared with Zn-supplemented rats. Disaccharidase activities were lower in the Zn-deficient group, compared with their feed-restricted counterparts, but were similar to values for ad lib.-fed controls. Tissue alkaline phosphatase and disaccharidase activities were consistently higher after a 4 d period of Zn supplementation, compared with non-supplemented animals, but this increase was only significant for alkaline phosphatase. 4. Although there were striking similarities in the mucosal characteristics of gnotobiotic and Zn-deficient rats, there was no indication that even severe dietary Zn depletion reduced the numbers of viable bacteria present in either the small or large intestine.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline Phosphatase↗
PubMed1984

Influence of fixative osmolality on the morphometric determination of extracellular space in normal and reperfused ischaemic myocardium.

Morphometric determination of extracellular space in control and post-ischaemic reperfused rabbit myocardium was evaluated using two fixatives differing in their composition and total osmolality. Measurement of control extracellular space in an isotonic fixative (294 mOsm/kg water) was 20.8% and in a hypertonic fixative (1816 mOsm/kg water) was 22.2%. These values were not statistically different. Ischaemic durations of 15, 30, 60 and 90 min, followed by an equivalent period of reperfusion, created significant increases in extracellular space. The size of the extracellular space determined by both fixatives was found to be the same. Total fixative osmolality does not appear to influence morphometric evaluation of the extracellular space in control tissue or in tissue damaged by ischaemia and reperfusion.

Animals↗
PubMed1984

Characterization of plant polysaccharide- and mucin-fermenting anaerobic bacteria from human feces.

Organisms able to grow on arabinogalactan, pectin, xylan, wheat bran, guar, apple cell walls, and mucin were isolated by enrichment from human feces. The number of polysaccharide fermenters and the properties of the predominant bacteria varied between subjects. The ability to use one polysaccharide was not related to the ability to use others. Some organisms (e.g., Bacteroides spp.) isolated on other substrates also utilized mucin, but were not isolated in the mucin enrichment. The mucin fermenters isolated by enrichment had a very restricted ability to utilize complex polysaccharides and their constituent monosaccharides, suggesting that the presence of plant polysaccharides in the human colon is unlikely to prevent the use of colonic mucin as an energy source by bacteria. Characterization with a range of biochemical tests showed that many of the isolates, but especially the mucin fermenters, did not resemble organisms described previously.

Bacteria, Anaerobic↗
PubMed1983

Bacterial populations associated with different regions of the human colon wall.

The microorganisms associated with the undiseased human colon wall were examined in material obtained from four sudden-death victims. In traffic accident subjects (aged 45 and 16 years) the anaerobe-aerobe ratio was about 10(4):1 in all areas of the colon examined, whereas in acute heart failure subjects (aged 74 and 46 years) the ratio was as low as 1.2:1. The flora of each individual was distinct and complex. Although the predominant anaerobes isolated were Bacteroides and Fusobacterium spp., which composed over 50% of the flora in some samples, the species isolated (indicated by morphology and glucose fermentation products) varied between individuals. Other major types observed were gram-positive nonsporing rods, including Bifidobacterium spp., and anaerobic cocci (between 8 and 20% of isolates). Clostridia were only isolated in significant numbers from one individual. Scanning electron microscopy showed that most of the organisms were present below the top surface of the mucin layer overlying the mucosa. The use of several different preparative procedures for microscopy showed a complex microbial structure within the mucus, but major variations in the bacterial populations in different areas of the colon were not found. Spiral-shaped organisms up to 60 mum long in the form of double helices were found in two subjects by scanning electron microscopy but were not isolated during the parallel bacteriological investigation. The differences between this and previous studies are discussed in relation to experimental procedures and also in contrast to results with animals that showed a particularly specialized flora associated with the colon wall.

Adolescent↗
PubMed1983

Treatment of the arthropathy of familial hypercholesterolaemia.

A 29-year-old woman suffering from the arthropathy of familial hypercholesterolaemia was treated with a fat-modified low-cholesterol diet and colestipol. Symptomatic improvement occurred in association with a moderate reduction in the plasma cholesterol concentration. The pathogenesis of the musculoskeletal features of this disease is reviewed, and the implications of this patient's therapeutic response are explored.

Adult↗
PubMed1981

Evaluation of the effect of pentobarbitone anaesthesia on the plasma potassium concentration in the rabbit and the dog.

The purpose of these studies was to determine the reasons for the hypokalaemia observed in rabbits studied in our laboratory. The rabbits consumed standard rabbit chow which is rich in potassium and remained in potassium balance. Hypokalaemia was only observed following anaesthesia. A number of additional investigations were undertaken to clarify the mechanisms involved. The hypokalaemia could not be attributed to technical factors, alkalaemia, hyperinsulinaemia or hyperaldosteronism, but seemed to be a function of anaesthesia. This effect of pentobarbitone anaesthesia was not unique to the rabbit, as similar changes also occurred in the anaesthetized dog. The findings reported in this paper have significant implications with respect to the interpretation of plasma potassium concentrations in anaesthetized subjects or animals.

Acid-Base Equilibrium↗
PubMed1981

The prevalence of Raynaud's syndrome in rheumatoid arthritis.

To test the validity of the putative association between Raynaud's syndrome and rheumatoid arthritis (RA) 277 patients with rheumatic disorders were questioned about cold-induced colour reactions in the extremities. The time to recover digital temperature after brief immersion in ice water was used to confirm the presence of Raynaud's syndrome. The prevalence of Raynaud's syndrome in the 148 patients with RA and the 59 patients with osteoarthritis was 2.7% and 5.1% respectively. It is concluded that Raynaud's syndrome is not a frequent accompaniment of RA, and it is suggested that in view of the close association between Raynaud's syndrome and certain other disorders, such as mixed connective tissue disease and scleroderma, when patients present with polysynovitis and Raynaud's syndrome special consideration should be given to these conditions.

Arthritis, Rheumatoid↗
PubMed1981

Myocardial contracture: the predominant causes of impeded reperfusion in simulated surgical ischemia.

"Worst-case" surgical conditions were simulated using the isolated model of a parabiotically perfused rabbit heart septum. Such conditions occur clinically in regional myocardium distal to stenosed coronary arteries and are characterized by inadequate or absent ionic influence on the myocardium by chemical cardioplegia and equilibration to room temperature. This study tested the hypothesis that ischemic contracture, rather than intracellular or extracellular edema, critical closing or delayed critical opening, was the predominant cause of impeded reperfusion that damages myocardium. In 20 reperfused ischemic septa, conductance (flow per unit pressure) decreased significantly (P less than 0.05) as ischemia at 24 degrees C was prolonged from 15 to 90 minutes and as contracture became more severe. Conductance was not decreased significantly by even large amounts of extracellular edema. Intracellular edema did not occur. In 17 normal septa, the critical closing pressure was 9.3 mm Hg. Critical opening pressures following 5 to 90 minutes ischemia at 24 degrees C did not differ significantly. Although early reflow was impeded progressively with longer ischemic intervals, it was not significant as was due to contracture rather than critical closing or delayed critical opening. This study confirmed the hypothesis that contracture is the predominant cause of impeded reperfusion in simulated surgical ischemia.

Animals↗