PubMed Health⌕ Search

Biomedical subjects

J Tomlin

Publications and source records attributed to J Tomlin.

13 recordsLinked to original sources
PubMed1991

Is rectosigmoid response to food modulated by proximal colon stimulation?

Rectosigmoid motor activity and postprandial breath hydrogen levels were monitored in eight healthy males under basal conditions and for 3 1/2 hr after a meal (beefburger and breadroll and ice cream incorporating 20 g lactulose). Within minutes of ingestion there was a significant increase in motility index (P less than 0.05) and also an initial temporary rise in breath hydrogen. A late increase in motor activity occurred in seven of eight subjects 123 +/- 19 min after the meal and was temporally related to the beginning of a second, much larger rise in breath hydrogen (r = 0.99; P less than 0.01). The close association between the timing of the rises in breath hydrogen and rectosigmoid motor activity would support the possibility that the latter may be generated by chemical or mechanical stimulation of the proximal colon.

Adult↗
PubMed1991

Investigation of normal flatus production in healthy volunteers.

Flatulence can cause discomfort and distress but there are few published data of normal patterns and volumes. Twenty four hour collections were made using a rectal catheter in 10 normal volunteers taking their normal diet plus 200 g baked beans. Total daily volume ranged from 476 to 1491 ml (median 705 ml). Women and men (both n = 5) expelled equivalent amounts. The median daily flatus hydrogen volume was 361 ml/24 h (range 42-1060) and the carbon dioxide volume 68 ml/24 h (range 25-116), three volunteers produced methane (3, 26, and 120 ml/24 h), and the remaining unidentified gas (presumably nitrogen) or gases contributed a median 213 ml/24 h (range 61-476). Larger volumes of flatus were produced after meals than at other times. Flatus produced at a faster rate tended to contain more fermentation gases. Flatus was produced during the sleeping period, but the rate was significantly lower than the daytime rate (median 16 and 34 ml/h respectively). Ingestion of a 'fibre free' diet (Fortisip) for 48 hours significantly reduced the total volume collected in 24 hours (median 214 ml/24 h), reduced the carbon dioxide volume (median 6 ml/24 h), and practically eradicated hydrogen production. The volume of unidentified gas was not significantly affected (median 207 ml/24 h). Thus fermentation gases make the highest contribution to normal flatus volume. A 'fibre free' diet eliminates these without changing residual gas release of around 200 ml/24 h.

Adult↗
PubMed1990

The effect of resistant starch on colon function in humans.

Starch that is resistant to human amylases forms during the cooking and subsequent cooling of some foods, and may therefore be a substrate for the bacterial flora of the colon. It is thus possible that resistant starch (RS) will affect colon function in a similar manner to non-starch polysaccharides. To test this theory, a group of eight volunteers took two diet supplements for 1 week each in a random order with a 1 week separation. One supplement comprised mainly 350 g Cornflakes/d and the other 380 g Rice Krispies/d, providing 10.33 and 0.86 g RS/d respectively. The amounts of amylase-digestible starch, nonstarch polysaccharides, total carbohydrate, energy, protein and fat were balanced between the two periods by giving small amounts of Casilan, wheat bran, butter and boiled sweets. The volunteers made faecal collections during day 3 to day 7 of each period. Whole-gut transit time was calculated using the continuous method. Stool consistency and ease of defaecation were assessed by the volunteers. All episodes of flatulence noticed were recorded in a diary, along with food intake. Serial breath hydrogen measurements were made at 15 min intervals for 8 h on day 1 of each supplement. Questionnaires regarding colon function were completed at the end of each dietary period. There were no significant differences in the stool mass, frequency or consistency, ease of defaecations, transit time or flatulence experienced during the two supplements (P greater than 0.05). Significantly more H2 (area under curve) was produced while eating Cornflakes than Rice Krispies (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Amylases↗
PubMed1988

The relation between bacterial degradation of viscous polysaccharides and stool output in human beings.

1. The relation between bacterial degradation of three viscous polysaccharides (guar gum, ispaghula and xanthan gum) by colonic bacteria in vitro and their effects on colonic function were investigated by comparing the results of anaerobic in vitro incubations with fresh faeces from seven healthy volunteers (measuring viscosity, pH and gas production) with the effects of feeding all three polysaccharides to the same volunteers for 1 week each (14-15 g/d) on faecal mass and whole-gut transit time. 2. Guar gum was rapidly fermented in vitro by faecal bacteria from all volunteers with concomitant loss of viscosity, reduction in pH and generation of gases. Ispaghula maintained its viscosity during incubation, but the pH fell significantly. The results of xanthan gum incubations showed considerable individual variation. 3. Only ispaghula significantly increased faecal mass, whilst none of the gums significantly affected stool frequency or transit time. Statistical analysis of the pooled results showed that although transit time and faecal output were inversely related, feeding viscous polysaccharides could influence these indices independently. Stool frequency was significantly correlated with the transit time, but not the faecal output. 4. Transit time was reduced by gum feeding to a significantly greater extent in those subjects whose faecal bacteria reduced or removed the viscosity of that gum, than in those subjects where the viscosity was maintained. In contrast, there was a smaller increase in faecal mass when the viscosity of the appropriate cultures was removed than when it was maintained or reduced. Increases in stool frequency were significantly associated with hydrogen production from in vitro cultures.

Adult↗
PubMed1988

A comparative study of the effects on colon function caused by feeding ispaghula husk and polydextrose.

Polydextrose is a new soluble food ingredient which cannot be digested by intestinal enzymes and so may affect colonic function. Studies in healthy volunteers compared the effects of diet supplementation with 30 g/day polydextrose, a standard dose of 7 g/day ispaghula and two mixtures containing 2 g/day ispaghula with either 30 g/day polydextrose or 10 g/day polydextrose with a control period. During the 10-day periods, the mass, frequency and consistency of faeces were assessed as well as the whole-gut transit time, ease of defaecation, flatulence and palatability of the preparations. All preparations significantly increased the weekly faecal mass above control values (P less than 0.05) but there were no significant differences between the preparations. Transit time and stool frequency were not affected significantly by any of the preparations (P greater than 0.05). Both preparations supplying 30 g/day polydextrose softened stool consistency equally but the other preparations had no effect. All preparations caused flatulence and other gas-related problems but polydextrose caused more than ispaghula, even at the lowest dose of 10 g/day. More volunteers preferred taking the polydextrose drinks than the sachets of ispaghula which formed a viscous drink with water. Despite superior palatability and equally effective stool bulking, polydextrose is unlikely to be an alternative laxative to ispaghula because of the unacceptable levels of flatulence.

Adult↗
PubMed1988

Comparison of the effects on colonic function caused by feeding rice bran and wheat bran.

A study was designed to investigate the effects of a new fibre source, rice bran, on colonic function, and to compare it with wheat bran. The diet of eight normal male volunteers was supplemented with similar amounts of indigestible residue from rice (17.1 g/d) and wheat bran (15.0 g/d) for periods of 10 d each. During the last 7 d of each of these periods, and also of a 10-d control period when no supplement was taken, the volunteers collected their stools into plastic bags. This allowed calculation of stool mass and frequency, and gastrointestinal transit time by a continuous radio-opaque marker technique. Rice bran increased the mass of faeces produced and the stool frequency by more than the wheat bran, but both had a similar accelerating effect on the transit time. The mechanism of the efficient stool bulking caused by the rice bran may be due to a high content of retrograded starch.

Adult↗
PubMed1987

Viscosity of food gums determined in vitro related to their hypoglycemic actions.

Experiments were carried out in vitro and in normal human subjects to evaluate alternative food-grade viscous polysaccharides as agents for reducing postprandial hyperglycemia and to assess the relationship between the in vitro and in vivo performance of the polysaccharides. A 1:1 mixture of xanthan and locust bean gum (X/LBG) had the greatest viscosity at equivalent concentrations and shear rates and was more effective than guar gum, xanthan, or locust-bean gum at inhibiting glucose movement in vitro. It was not, however, more efficient in lowering postprandial blood glucose and plasma insulin in human subjects when incorporated in a drink containing 50 g glucose. When the different gums were acidified and reneutralized to mimic conditions in the gut, there was a better correlation between viscosity and blood glucose and plasma insulin levels. This effect may explain why X/LBG was no more effective than the other gums in reducing postprandial hyperglycemia in man.

Adolescent↗
PubMed1986

The degradation of guar gum by a faecal incubation system.

1. Homogenized and diluted faeces (50 g/l) from one human source were incubated with the complex plant polysaccharide, guar gum, to investigate the degradation of viscous polysaccharides by intestinal bacteria. 2. Incubation of the faecal homogenate with guar gum produced a rapid decrease in viscosity and in pH, accompanied by the release of hydrogen. 3. No changes in viscosity or pH were observed and there was no production of H2 gas when guar gum was incubated with autoclaved faecal homogenate (20 min, 1.03 x 10(5) Pa). 4. A bacteria-free filtrate of faeces was prepared by centrifuging the faecal homogenate (2400 g for 100 min) followed by filtration through a Seitz filter and then a millipore filter (size 0.45 micron). Incubating this with guar gum produced a slow decrease in viscosity, but no significant change in pH and no generation of H2. 5. Our results show that guar gum can be fermented by human colonic bacteria and suggest the possibility of predigestion by extracellular free enzymes.

Bacteria↗