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Biomedical subjects

I Nordgaard

Publications and source records attributed to I Nordgaard.

13 recordsLinked to original sources
PubMed2002

Colonic production of nitric oxide gas in ulcerative colitis, collagenous colitis and uninflamed bowel.

BACKGROUND: Nitric oxide (NO) produced in excess by the inflamed human colon is generally considered a pathway of mucosal damage. In an attempt to quantify colonic mucosal production of NO in various forms of colitis we performed 'steady-state' gas perfusion of whole colon in 11 patients with ulcerative colitis, 10 patients with collagenous colitis and 20 controls with uninflamed mucosa. METHODS: The tip of a Teflon tube was placed in the caecum during colonoscopy. Subsequently, argon was infused at a constant rate for 70-180 min. Argon and NO in gas sampled from the rectum were measured by neutron activation analysis and the chemiluminescence technique, respectively. RESULTS: The use of argon as a marker of colonic NO output was justified by complete recovery (96%+/-2; mean +/- s(x); n = 5) of argon in gas collected from the rectum and a constant output of NO at varying perfusion rates (25, 50 and 75 ml/min coefficient of variation 21%; n = 6). In patients with ulcerative colitis, colonic output of NO was 10-fold higher (P < 0.001) than in controls and positively correlated (P < 0.01) to indices of disease activity. In patients with collagenous colitis, colonic output of NO was 50-fold higher (P < 0.01) than in controls during periods with watery diarrhoea (n = 6), but within the range observed in ulcerative colitis in the absence of diarrhoea (n = 4). CONCLUSIONS: Argon gas perfusion of whole colon using chemiluminescence technique for measurement of NO is a reliable method for quantification of colonic mucosal NO production. Increased colonic production of NO in collagenous colitis, which exceeds the output observed even in extensive ulcerative colitis, militates against the theory that NO per se is a cause of mucosal injury.

Adult↗
PubMed1996

Importance of colonic support for energy absorption as small-bowel failure proceeds.

Digestive processes in the human colon are affected by the bacterial fermentation of malabsorbed carbohydrates and protein to short-chain fatty acids, which are absorbed and supply energy. Energy absorption was measured by assessing fecal bomb calorimetry in 148 patients with extremely different small-bowel lengths. Colectomy increased fecal loss of energy by 0.8 MJ/d and carbohydrate excretion fivefold in patients with a small-bowel length between normal and 150-200 cm. Patients with 100-150 cm small bowel, with and without a colon, excreted 1.3 +/- 0.3 and 4.7 +/- 0.5 MJ/d, respectively (P = 0.002), a difference of 3.4 MJ/d. Patients with < 100 cm small bowel excreted 3.1 +/- 0.4 and 8.0 +/- 1.3 MJ/d, respectively (P = 0.03), a difference of 4.9 MJ/d. Similar and highly significant differences were calculated by linear-regression analysis. Considerably less energy was excreted as carbohydrate than as fat in patients with preserved colonic function, probably because fermentation removed carbohydrate as absorbed short-chain fatty acids, whereas a comparable amount of energy was lost as carbohydrate and fat in patients without colonic function. The correlation between malabsorbed energy and small-bowel length was poor (r = -0.41) but increased when data for patients with and without a colon were separated (r = -0.56 and r = -0.58, respectively). Small-bowel length, however, was still an inaccurate measure of intestinal failure to absorb nutrient energy. In conclusion, colonic digestion may support energy supply with up to approximately 4.2 MJ/d as small-bowel failure proceeds, but it is of minor importance in patients with a small-bowel length > 200 cm or malabsorption < 2.1 MJ/d.

Adolescent↗
PubMed1996

Colonic production of butyrate in patients with previous colonic cancer during long-term treatment with dietary fibre (Plantago ovata seeds).

BACKGROUND: Butyrate has antineoplastic properties against colorectal cancer cells and is the preferred oxidative substrate for colonocytes. Like acetate and propionate (short-chain fatty acids; SCFAs), butyrate is produced by colonic fermentation of dietary fibre. METHODS: Twenty patients resected for colorectal cancer were treated with 20 g/day of the fibre Plantago ovata seeds for 3 months, which increased the intake of fibre by 17.9 +/- 0.8 g/day, from basal levels of 19.2 +/- 1.7 g/day; 17 patients completed the study. Faecal samples were obtained on eight occasions, twice before treatment, and monthly three times during and three time after treatment. RESULTS: One month of fibre therapy increased faecal concentrations of butyrate by 42 +/- 12% (from 13.2 +/- 1.2 to 19.3 +/- 3.0 mmol/l; P < 10(-4)), acetate by 25 +/- 6% (P < 10(-4)), propionate by 28 +/- 9% (P = 0.01), and total SCFAs by 25 +/- 6% (P < 10 (-4)). Concentrations were increased during the 3-month fibre treatment but reversed to pretreatment levels within 1 to 2 months after cessation of fibre supplementation. The relative concentration (ratio) of butyrate was not altered owing to a simultaneous increase in acetate and propionate. Faecal pH decreased initially but was normalized after 2 months of fibre supplements. Fibre therapy increased the 24-h productions of butyrate by 47 +/- 10% (P < 10(-4)) and acetate by 50 +/- 7% (P < 10(-4)) in 16.6% faecal homogenates with added P. ovata seeds (20mg/ml), but SCFA productions returned to pretreatment levels after discontinuation of additional fibre intakes. CONCLUSIONS: Oral intake of P. ovata seeds adapted the colonic flora to increase the production of butyrate (and acetate) from this fibre and increased faecal concentrations of butyrate by 42% in patients resected for colonic cancer. The effects depended on continuity of treatment.

Aged↗
PubMed1995

Estimation of the fermentability of dietary fibre in vitro: a European interlaboratory study.

Five European laboratories tested a simple in vitro batch system for dietary fibre fermentation studies. The inoculum was composed of fresh human faeces mixed with a carbonate-phosphate buffer complex supplemented with trace elements and urea. Five dietary fibre sources (cellulose, sugarbeet fibre, soyabean fibre, maize bran and pectin) were used by each laboratory on three occasions to determine pH, residual non-starch polysaccharides (NSP) and short-chain fatty acid production during fermentation. Cellulose and maize bran degradabilities were very low (7.2(SE 10.8) and 6.2 (SE 9.1)% respectively after 24 h), whereas pectin and soyabean fibre were highly degraded (97.4 (SE 4.4) and 91.1 (SE 3.4)% respectively after 24 h). Sugarbeet fibre exhibited an intermediate level of degradability (59.5 (SE 14.9)%). Short-chain fatty acid production was closely related to NSP degradation (r 0.99). Although each variable was ranked similarly by all laboratories, some differences occurred with respect to absolute values. However, the adaptation of donors to the experimental substrates was not an influential factor. Interlaboratory differences could be reduced either by adding less substrate during incubations or using less-diluted inocula. In vitro fermentations with inocula made from human faeces and from rat caecal contents gave similar results. There was a close correspondence between the data obtained in the present experiment and those previously published in in vivo studies in the rat using the same fibres. The in vitro batch system tested during the present study provides a rapid means of obtaining quantitative estimates of the fermentation and the estimation of the energy content of new sources of dietary fibre.

Animals↗
PubMed1995

Colonic fermentation of complex dietary carbohydrates in short-bowel patients. No association with hydrogen excretion and fecal and plasma short-chain fatty acids.

BACKGROUND: The colonic degradation of carbohydrates (fermentation) to short-chain fatty acids (SCFAs) appears to have major impacts on colonocyte function, sodium and water absorption, and large-bowel energy salvation, but how to quantify the in vivo fermentation in man is still debatable. METHODS: Indicators of colonic fermentation, fecal and plasma SCFAs and breath hydrogen (H2), were measured in 10 short-bowel patients (mean +/- SE; 106 +/- 21 cm) with totally preserved large bowels who were on a 60% high-carbohydrate, 20% low-fat diet, compared with the reversed isocaloric 20% low-carbohydrate, 60% high-fat diet. This human model showed large differences in large-bowel fermentation, as excretions of calories were reduced (40%; 485 +/- 151 kcal/day) and excretions of carbohydrates were unchanged and low with the high-carbohydrate diet as compared with the low-carbohydrate diet, in contrast to unchanged calorie excretion in short-bowel patients with no colonic function. RESULTS: Fecal concentrations of SCFAs did not change when the diet was changed from the high content to the low content of carbohydrates (82 +/- 11 mmol/l and 79 +/- 9 mmol/l, respectively). The ratio of acetate in feces increased (from 48 +/- 4% to 54 +/- 3%; p = 0.01) on the high-carbohydrate diet, whereas the percentage of the other SCFAs decreased proportionally. Plasma SCFAs 2 h and 6 h after breakfast were also identical when comparing the two dietary regimens. Nor were the peak H2 breath excretion and the area under the H2 excretion-versus-time curve increased by the threefold increase in the intake of dietary carbohydrates. CONCLUSIONS: Fecal and plasma SCFAs and breath H2 excretion are of limited value in the evaluation of even large differences in colonic fermentation of complex dietary carbohydrates.

Adult↗
PubMed1994

Colon as a digestive organ in patients with short bowel.

Patients with a short bowel malabsorb dietary nutrients with loss of calories and weight. Malabsorbed carbohydrates are fermented by colonic bacteria to short-chain fatty acids, which are absorbed and supply energy. The maximum energy-consumption capacities in patients with short bowel were individually measured on 40:40% carbohydrate:fat diets. 8 patients with colon in continuity and 6 patients with jejunostomies were placed on isocaloric 60:20% or 20:60% carbohydrate:fat diets and faecal excretions of calories, carbohydrates, fat, nitrogen, and fluids were compared. The high-carbohydrate low-fat diet reduced faecal loss of energy by 2.0 MJ/day compared to the low-carbohydrate high-fat diet in patients with colon in continuity, and absorption of energy increased from 49 to 69% (p < 0.001). Faecal excretions of carbohydrates were low and not influenced by the change in carbohydrate intakes (26 g/day and 28 g/day, respectively) whereas faecal fat (46 g/day and 106 g/day) was highly dependent on dietary intakes and accounted for differences in faecal loss of energy. In contrast, patients with jejunostomies excreted equal amounts of calories on the high-carbohydrate diet (4.8 MJ/day) and the high-fat diet (5.9 MJ/day; p = 0.08); and the percentage of calories absorbed was not different (55% and 48%, respectively; p = 0.21). Furthermore, in patients without colon the excretions of carbohydrates (80 g/day and 42 g/day on high-carbohydrate and low-carbohydrate diets, respectively) and fat (69 g/day and 35 g/day on high-fat and low-fat diets, respectively) were proportional to the amounts ingested. The large intestine is important in the digestion of carbohydrates and hence in the salvage of calories in patients with short bowel and severe malabsorption.

Adult↗
PubMed1994

Working capacity and expression of myosin heavy chain isoforms in skeletal muscle of chronic alcoholic men without liver disease after 1 day and 4 weeks of alcohol abstinence.

1. The aim of this study was to examine the effect of chronic alcohol ingestion on working capacity and on the expression of myosin heavy chain isoforms in fibre types of human skeletal muscle. 2. Six alcoholic men having drunk more than 240 g of alcohol/day for more than 10 years underwent a test for working capacity and a muscle biopsy on the first day of alcohol abstinence (test 1) and again after 4 weeks of abstinence (test 2). The biopsies were analysed using histochemical, immunochemical and gel-electrophoretic techniques, and the results were compared with those from eight age-matched non-alcoholic control subjects. 3. The area of type IIB muscle fibres was decreased by 33% in the alcoholic patients compared with normal control subjects at both test 1 and test 2. The area of type IIA fibres was lower (13%) in alcoholic patients at test 1 than in the control group, and increased to the normal level at test 2. 4. The relative proportion of fibres expressing only myosin heavy chain type IIB isoforms was one-third of normal in the alcoholic patients at both tests 1 and 2. The relative proportion of fibres expressing only myosin heavy chain type IIA isoforms was the same in alcoholic patients at test 1 and in normal control subjects, but increased by 25% between test 1 and 2 in the alcoholic group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Assimilation of wheat starch in patients with chronic pancreatitis. Positive effect of enzyme replacement.

Pancreatic insufficiency due to chronic pancreatitis may lead to symptomatic malabsorption of both starch and fat. The absorption capacity of wheat starch has not been studied previously in patients with chronic pancreatitis, although this carbohydrate is a quantitatively important component of the Western diet. We studied the absorption of wheat starch and the effect of pancreatic enzyme substitution in seven patients with chronic pancreatitis and steathorrea. The malabsorption was determined from hydrogen breath tests with lactulose standards as reference. Without enzyme substitution, wheat starch (50 g) was absorbed to a lesser extent than in healthy controls (p less than 0.05). The mouth-to-cecum transit time was prolonged and correlated positively to the fat excretion before substitution with pancreatic enzymes (sigma = 1). The enzyme substitution increased the absorption of wheat starch to values seen in healthy controls (p less than 0.05) and reduced the mouth-to-cecum transit time by 19.8%.

Adult↗
PubMed1992

Absorption of wheat starch in patients resected for left-sided colonic cancer.

Bacterial fermentation of carbohydrate in the colon, producing short-chain fatty acids (SCFA)--and especially butyrate--has been shown possibly to impede cell proliferation and regulate cell differentiation of colonocytes. In patients with diverticular disease or benign polyps in the colon a hyperabsorption of potato starch in the small intestine has been found. We have investigated the absorption of wheat starch in 15 patients radically resected for cancer in the descending or sigmoid colon, and the results were compared with those of 15 healthy controls. The starch malabsorption was quantified by the hydrogen breath test. The patients malabsorbed 2-14 g (median, 8 g) of 100 g wheat starch ingested, and the control group malabsorbed 3-11 g (median, 6 g) (P greater than 0.1). Mouth-to-cecum transit time for wheat starch and lactulose and the hydrogen production capacity after the lactulose standards were also similar in patients and controls. The results do not support the theory that hyperabsorption of starch is characteristic of patients with malignant disease in the large intestine.

Adult↗
PubMedDate not supplied

Small intestinal malabsorption and colonic fermentation of resistant starch and resistant peptides to short-chain fatty acids.

Some starch and protein, as well as fiber, remains unabsorbed in the small intestine and is degraded by anaerobic bacteria to short-chain fatty acids, hydrogen, methane, and carbon dioxide in the large intestine. The production of butyrate from starch has received the most attention, because butyrate seems to possess several important functions in the large bowel, including antineoplastic properties. In 16.6% fecal homogenates, starch polysaccharides, whether digestible or resistant to in vitro hydrolysis by amylase, pectin, and glucose, were all completely degraded to equal amounts of short-chain fatty acids (mean 60 wt/wt%; range 49-67 wt/wt%). However, starch that was resistant to hydrolysis by amylase was much more slowly fermented with the production of proportionally less butyrate and propionate than digestible starch (butyrate, 15 and 33%, respectively; propionate, 3 and 20%, respectively). The daily intake of 35 g resistant starch (100 g amylomaize starch) by 7 ileostomy subjects increased ileal dry-matter effluent by 38 +/- 2 g/day, due exclusively to increased excretion of carbohydrates of nonfiber origin (starch-polysaccharides and oligo- and monosaccharides) from 14 +/- 1 to 51 +/- 2 g/day, with no change in excreted nonstarch polysaccharides, nitrogen, and ileal volume. The ileal excreted resistant starch increased the formation of total short-chain fatty acids by 50% in fecal homogenates incubated with ileal dry matter from the amylomaize starch period, with comparatively little effect on the ratio of produced butyrate.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Digestive processes in the human colon.

The presence or absence of a normal small bowel is evidently important for the digestion and absorption of nutrients in humans. The importance, however, of the large intestine as an organ with digestive potential and an ability to salvage energy is much less appreciated. Whereas the bacterial fermentation of plant polysaccharides, with the production and absorption of short-chain fatty acids (SCFAs), contributes 60-90% of all the energy requirements in plant-eating animals, the colonic fermentation in humans is of minor importance for nutrition, with only 5-10% of the energy requirements available from colonic digestion of starch, nonstarch polysaccharides, and protein not absorbed in the small bowel, if the intestine has a normal length and function. In contrast, the digestive resource of the large bowel might be important for people with reduced upper-gut function and with the malabsorption of large amounts of dietary nutrients to the cecum, e.g., in patients with short bowel. The substrates available for bacterial fermentation and for the maintenance of the colonic flora are largely starch and nonstarch polysaccharides (dietary fiber). Whereas nonstarch polysaccharides are undegradable by amylase in the small intestine, starch is hydrolyzed by amylase, but with very different rates and to very different degrees dependent on the origin and structure of the starches. The unequal susceptibility to amylase explains the different amount of starch that is not absorbed in the small intestine. The rate of colonic fermentation of starch has also been shown to relate to the rate of starch hydrolysis by amylase.(ABSTRACT TRUNCATED AT 250 WORDS)

Colon↗