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T Høverstad

Publications and source records attributed to T Høverstad.

25 records · Page 2Linked to original sources
PubMed1985

Short-chain fatty acids in intestinal content of germfree mice monocontaminated with Escherichia coli or Clostridium difficile.

The short-chain fatty acids (SCFAs) have been analysed in coecal and small-intestinal content of conventional (CONV) and germfree (GF) mice, in germfree mice monocontaminated with Escherichia coli (MEC) or Clostridium difficile (MCD), and in germfree mice conventionalized by the visitor technique (EXG). The total concentrations of SCFAs in coecal content, measured by gas chromatography, were (mean (SD), mmol/kg): CONV, 125.2 (32.9); GF, 1.02 (0.39); MEC, 6.88 (0.76); MCD, 4.50 (0.12); and EXG, 115.6 (17.4). The concentrations of SCFAs were 3- to 25-fold higher in the coecum than in the small intestine in CONV, MEC, and EXG mice (p less than 0.05). The fermentation patterns (that is, the relative composition of the acids) of E. coli and Cl. difficile were distinctively different under defined in vitro conditions and similar to those found in intestinal content of monocontaminated animals. Combined gas chromatography and mass spectrometry showed that Cl. difficile produced an unusual metabolite, 2-methylbutyric acid, in vitro and in vivo. The findings indicate that the fermentation patterns are closely related to the bacteria. Variations in the bacterial flora may be more important in determining the concentrations and patterns of SCFAs in intestinal content than variations in the intake of substrate for SCFAs formation as dietary fibre.

Animals↗
PubMed1985

Bacterial overgrowth.

Different aspects of bacterial overgrowth in the small intestine are reviewed. The pathophysiological mechanisms involving both bacterial metabolism of dietary components and secretions and effects on the mucosal cells are discussed in more detail. The current therapy, surgical, medical and supportive, is outlined.

Anti-Bacterial Agents↗
PubMed1984

Short-chain fatty acids and bowel functions in man.

The fecal excretion of short-chain fatty acids (SCFAs) (measured by gas chromatography), transit time (assayed by radiopaque plastic markers), fecal weight, intake of dietary fiber, and their relationship have been studied in 10 healthy subjects during 1 week. The subjects had a fiber intake (mean +/- SD) of 26.3 +/- 7.9 g/day, a fecal weight of 160 +/- 49 g/day, and an average transit time of 41 +/- 9 h and excreted 11.1 +/- 5.5 mmol of SCFAs/day, with a concentration of 66.7 +/- 28.0 mmol/kg feces. The mean amount of SCFAs, but not their concentration, correlated to mean fecal weight (p less than 0.01) and mean transit time (p less than 0.01). The mean fecal weight correlated to mean transit time (p less than 0.05). The mean intake of dietary fiber did not correlate to any of the other variables. The results of this study indicate that other substrates are more important than fiber for the bacterial formation of SCFAs in the colon. The SCFAs formed most likely do not exert any direct laxative effect.

Adult↗
PubMed1984

Short-chain fatty acids in the proximal gastrointestinal tract of healthy subjects.

The total concentration of short-chain fatty acids (SCFAs) in healthy subjects, measured by gas chromatography, was in saliva and jejunal aspirates (n = 6) (median (range] 4480 (2780-9940) mumol/l and 265 (185-1470) mumol/l and in gastric and duodenal aspirates (n = 7) 719 (425-1770) mumol/l and 480 (137-778) mumol/l, respectively. Acetic and propionic acid accounted for 85% and 11%, respectively, and i-butyric, n-butyric, and i-valeric for less than 2% each in jejunal aspirates. A very similar relative distribution was present also in saliva and gastric and duodenal aspirates, essentially different from that of feces. Through anaerobic culturing from jejunum, 10(3) to 10(8) bacteria/ml was obtained; there was no correlation between the log number of bacteria and the SCFAs concentration before and after ingestion of sucrose. Swallowed exogenous radiolabeled propionate was partly recovered in the jejunum. The findings indicate that the SCFAs recovered from the jejunum in healthy subjects are mainly produced in the mouth and swallowed with the saliva.

Adult↗
PubMed1984

Short-chain fatty acids in the normal human feces.

The short-chain fatty acids ( SCFAs ) have been studied in the feces of 20 healthy subjects--10 methane excretors and 10 non-methane excretors. The analytical procedure included homogenization of fecal samples followed by vacuum distillation and subsequent gas chromatography. This method for analysis of fecal SCFAs showed recoveries of the individual acids from 90% to 109% and coefficients of variation for the inter-assay reproducibility from 6.0% to 19.7%, highest for those acids present in the smallest concentrations. There was no difference in the concentrations or relative compositions of SCFAs between methane-excreting subjects and non-methane-excreting subjects. The concentrations of SCFAs , given as mmol/kg feces (wet weight), were (median and range): total, 76.8 (27.9-187.7); acetic acid, 37.4 (12.8-103.4); propionic acid, 12.5 (4.5-27.8); i-butyric acid, 2.2 (0.7-3.8); n-butyric acid, 12.4 (4.0-53.0); i-valeric acid, 3.2 (0.8-5.9); n-valeric acid, 2.4 (0.6-3.8) and n-caproic acid, 0.5 (0.0-3.6). The study shows that the SCFAs are quantitatively the most important anions in the feces of healthy subjects. The pronounced individual variations in the concentrations of SCFAs are real biological variations and cannot be explained by methodological variations.

Adult↗
PubMed1982

Absorption of short-chain fatty acids from the human colon measured by the 14CO2 breath test.

The absorption and metabolism of short-chain fatty acids (SCFAs) have been studied in 31 patients. Physiological amounts (7.5 mmol) of (1-14C)-labeled acetic, propionic, and butyric acid and (2-14C)-labeled propionic acid were instilled into the cecum and ascending part of the colon during colonoscopy, and the metabolism of acids to CO2 was measured for 24 h by the 14CO2 breath test. During the first 6 h the cumulative output of 14CO2 from the (1-14C)-labeled acetic, propionic, and butyric acids were (median and range) 50% (46%-56%), 50% (43%-56%), and 63% (58%-73%) and during 24 h 55% (50%-63%), 58% (46%-60%), and 70% (63%-83%), respectively, of the instilled dose. The elimination patterns of the (1-14C)-labeled acids were rather similar, although butyric acid was eliminated to a somewhat greater extent than acetic and propionic acid (p less than or equal to 0.01). (2-14C)-labeled propionic acid was eliminated more slowly than (1-14C)-labeled propionic acid, with a cumulative output of 37% (30%-39%) after 6 h (p less than 0.01), but reached the same value after 24 h, 54% (47%-60%). In agreement with findings in other species, humans have a great capacity for uptake and metabolism of SCFAs formed in the colon.

Acetates↗