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Biomedical subjects

V M Duncombe

Publications and source records attributed to V M Duncombe.

At least 37 records · Page 2Linked to original sources
PubMed1995

Bacteriologic analysis of mucosal biopsy specimens for detecting small-intestinal bacterial overgrowth.

BACKGROUND: Although culture of luminal secretions is regarded as the most accurate diagnostic test for small-intestinal bacterial overgrowth, obtaining an aspirate is often difficult owing to the sparseness of luminal secretions present at the time of aspiration. Obtaining a mucosal biopsy specimen for bacteriologic analysis would overcome this problem. METHODS: Culture of small-intestinal and gastric aspirates and unwashed small-intestinal mucosal specimens was performed in 51 adult subjects investigated for small-intestinal overgrowth. RESULTS: Highly significant (r = 0.85-0.90; p < 0.0005) correlations were found between viable bacterial counts in small-intestinal luminal secretions and biopsy specimens. Small-intestinal bacterial overgrowth was present in 60.8% of subjects. When specimens weighing 4.0-84.0 mg were suspended in diluent, total aerobic and/or anaerobic bacterial counts > or = 10(2) CFU/ml were found to have 90.3% sensitivity and 100% specificity for small-intestinal bacterial overgrowth. CONCLUSION: Culture of an unwashed small-intestinal mucosal biopsy specimen is a useful alternative to culture of a small-intestinal aspirate for detecting subjects with small-intestinal bacterial overgrowth, especially when luminal secretions are scanty at the time of aspiration.

Adult↗
PubMed1995

Factors influencing the 1-g 14C-D-xylose breath test for bacterial overgrowth.

OBJECTIVES: To document the sensitivity of the 1-g 14C-D-xylose breath test for bacterial overgrowth and to investigate luminal and nonluminal factors that may influence breath 14CO2 levels and impact on the clinical utility of this test. METHODS: Thirty-five adult subjects were investigated for bacterial overgrowth by culture of gastric and small intestinal aspirates and by a 1-g 14C-D-xylose breath test. Body weight, gastroduodenal pH and the in vitro capability of overgrowth flora to ferment D-xylose were assessed. Serial breath 14CO2 levels were also recorded before and after the resolution of malabsorption in a subject with celiac disease to determine the importance of postabsorptive metabolism of this substrate. RESULTS: Gastric and small intestinal bacterial overgrowth were present in 19/35 (54.3%) and 21/35 (60.0%) subjects, respectively. The positivity rate of culture of aspirate exceeded that of the 1-g 14C-D-xylose breath test. Endogenous CO2 production independently influenced breath 14CO2 levels. After excluding this influence, sensitivity of the 1-g 14C-D-xylose breath test for gastric bacterial overgrowth or small intestinal bacterial overgrowth was poor, even when overgrowth with specific "marker organisms" was considered. Poor sensitivity could not be explained by unfavorable luminal pH. Overgrowth flora were proven capable of in vitro D-xylose fermentation in 81.8% of subjects. Systemic and/or colonic metabolism of 1-g 14C-D-xylose appear to be important factors influencing results of the 1-g 14C-D-xylose breath test, especially in partial gastrectomy subjects. CONCLUSIONS: The 1-g 14C-D-xylose breath test is not a suitable alternative to culture of aspirate for the investigation of subjects for bacterial overgrowth.

Aged↗
PubMed1995

An appraisal of a 'string test' for the detection of small bowel bacterial overgrowth.

The efficacy of a string test for the detection of small bowel bacterial overgrowth (SBBO) was determined by comparison with a sterile endoscopic method for sampling small bowel secretions in 15 subjects investigated for SBBO. Clinical value was found to be limited by poor sensitivity, specificity and positive predictive value. The string test is not an adequate substitute for oro-duodenal intubation for the detection of SBBO.

Adult↗
PubMed1992

Comparison of an in vitro faecal hydrogen test with the lactulose breath test: assessment of in vivo hydrogen-producing capability in Burmese village children.

In the assessment of carbohydrate malabsorption, it is important to determine if patients with a flat breath hydrogen (H2) response to an absorbable carbohydrate challenge are capable of producing H2. We compared the reliability of a rapid faecal incubation system with the lactulose breath test to assess in vivo H2 production in 64 children. Overall, 70% of subjects were in vivo H2-producers, with breath H2 peaks greater than 10 parts per million within 3 h of ingesting 10 g of the non-absorbable disaccharide lactulose. Faecal specimens from the 64 children had a mean (SE) pH of 5.0 (0.077). Faecal homogenates were incubated with lactulose at both the initially measured faecal pH and at neutral pH. In predicting a normal in vivo H2-producing ability (sensitivity), the faecal H2 test was correct in only 22% (faecal pH) to 44% (pH7) of cases. In predicting an abnormal lactulose breath test result (specificity), faecal homogenate analysis was correct in 53% of cases, at both faecal and neutral pH. These findings indicate that the faecal hydrogen test is unsuitable as a screening test for in vivo H2 production.

Breath Tests↗
PubMed1992

Absorption of carbohydrate from rice in Ascaris lumbricoides infected Burmese village children.

With the objective of determining the relationship between ascariasis and carbohydrate absorption from rice, breath hydrogen tests (BHT's) were performed in two study populations of Burmese village children. Using a rice test meal, breath hydrogen peaks greater than 10 ppm above baseline within 4 hours (indicating rice malabsorption) were seen in 24 out of 55 (44 per cent) Ascaris lumbricoides infected children and 3 out of 18 (17 per cent) non-infected children (age 18-59 months). In another ascaris endemic village 139 children (age 36-108 months) underwent a rice meal BHT. Seventy children had been regularly dewormed for 2 years (single dose levamisole 50 mg every 3 months) whilst 69 children had been dewormed once in 2 years, 6 weeks before breath testing. Regularly dewormed children showed a lower prevalence of rice malabsorption (33 per cent) compared to the control group (54 per cent) (P < 0.05). These findings suggest that malabsorption of carbohydrate from rice can occur during Ascaris lumbricoides infection in children.

Animals↗
PubMed1992

In vitro hydrogen production by enteric bacteria cultured from children with small bowel bacterial overgrowth.

Lactulose breath hydrogen test and Enterotest string test were carried out simultaneously on 19 children 3-5 years old. Bacteria isolated from the jejunal fluid in upper small intestines of these children were incubated with lactulose at neutral pH. Anaerobes were present in all but one child, and in 15 children they were present in numbers greater than 5 log10 organisms per ml. Most of these bacteria did not produce hydrogen in vitro. Hydrogen production (greater than 100 ppm) was observed with the following bacteria: Bacteroides (5%), clostridia (8%), anaerobic corynebacteria (5%), Escherichia coli (67%), Lactobacillus (8%), Staphylococcus (8%), and Streptococcus (9%). The following bacteria did not produce hydrogen in vitro: Actinobacter, Actinomyces, anaerobic cocci, Bifidobacterium, Fusobacterium, micrococci, Neisseria, Sarcina, and Veillonella. This study suggests that in the diagnosis of small bowel bacterial overgrowth using lactulose breath hydrogen test, it is important to consider that patients with a flat breath hydrogen response to a carbohydrate challenge during the first 60 min may be infected with enteric bacteria which are not capable of producing H2.

Bacteria↗
PubMed1992

Epidemiology of small bowel bacterial overgrowth and rice carbohydrate malabsorption in Burmese (Myanmar) village children.

Breath hydrogen tests were performed after a rice meal (3 g of cooked rice/kg of body weight, equivalent to 1 g of carbohydrate/kg of body weight) on 256 village children (age range 1-59 months) who were known hydrogen (H2) producers. Anthropometric measurements were made every three months and growth rates were calculated. A breath H2 excretion pattern that suggested small bowel bacterial overgrowth (SBBO), which was recognized as a transient maximum level of 10 ppm or more at 20-, 40-, or 60-min breath samples following the rice meal, was present in 53 (20.7%) children, and was more frequent in children 36-47 and 48-59 months old. This breath H2 excretion pattern was detected in 48 (33.3%) of 144 children who were rice malabsorbers (greater than 10 ppm H2 above baseline values in one of the breath samples taken between 90 and 240 min), and in only five (4.5%) of 112 rice absorbers. Children who had SBBO had a high relative risk (10.7) of being rice malabsorbers. Rice malabsorbers have a high relative risk (59.7) of having faltered growth, accompanied by a large etiologic fraction (94%). This same risk (6.68) and an etiologic fraction of 62% exist in children with untreated SBBO. These findings emphasize the need for interventions aimed at reducing the prevalence of SBBO or similar conditions as detected by the breath H2 excretion pattern to prevent rice malabsorption and growth faltering.

Bacteria↗
PubMed1991

A pattern of breath hydrogen excretion suggesting small bowel bacterial overgrowth in Burmese village children.

Breath hydrogen tests (BHTs) were performed on 340 Burmese village children aged 1-59 months. Normalization (correction of breath H2 values to a constant mean O2 level) eliminated the variations in H2 levels due to sleep, storage temperature, or duration of storage. After a 10 g lactulose test meal, 145 (42.6%) children produced less than 10 ppm H2 above basal values (non-H2 producers). Of 195 H2 producers, a pattern of breath hydrogen excretion suggesting small bowel bacterial overgrowth (SBBO)--recognized as a transient peak at the 20, 40, or 60 min breath samples following the lactulose test meal and distinguishable from the later colonic peak--was observed in 53 (27.2%), being significantly more frequent in male children, and exhibiting an age-prevalence pattern similar to that of acute childhood diarrhea in these villages. Diarrhea did not alter the state of H2 production (non-H2 producers remain non-H2 producers, and H2 producers remain H2 producers) although the magnitude of peak breath H2 changed.

Breath Tests↗
PubMed1990

Effect of short-term intermittent antibiotic treatment on growth of Burmese (Myanmar) village children.

To test the hypothesis that subclinical enteric infection (such as bacterial overgrowth), rice malabsorption, and growth faltering are causally linked, a field trial of low-dose, short-term, intermittent antibiotic treatment was carried out in 142 hydrogen-producing (by lactulose breath hydrogen test) Burmese village children aged 6-59 months. The children were randomly allocated treatment with metronidazole (20 mg/kg or 5 mg/kg daily), amoxycillin (25 mg/kg daily), or placebo given 1 week per month for 6 months. A cooked rice meal breath hydrogen test was done to classify the children as rice absorbers (RA) or rice malabsorbers (RM) before treatment and monthly on the day before each cycle of treatment. There were no differences between the treatment groups, so they were considered together. Factorial analysis showed that antibiotic treatment did not significantly affect the proportion of RM children. The only significant difference between antibiotic-treated and placebo-treated children's growth was in the subgroup of RM children aged 36-47 months; the antibiotic-treated children had significantly greater linear growth. In other age groups antibiotic treatment had no effect on growth.

Age Factors↗
PubMed1990

Absorption of carbohydrate from rice in Burmese village children and adults.

Breath-hydrogen tests (BHTs) were performed on 310 Burmese village children aged 1-59 mo. After a 10-g lactulose test meal, 94 (30.3%) children produced less than 10 ppm H2 above basal values (nonhydrogen producers). Of 216 hydrogen producers, 210 were tested after a cooked rice meal (3 g cooked rice/kg body wt, equivalent to 1 g carbohydrate/kg body wt) with the BHT. Hydrogen peaks greater than or equal to 10 ppm above baseline concentrations were produced by 133 (66.5%) children who were defined as rice malabsorbers. Forty-three percent to 62% of children were less than or equal to -3 SD of the National Center of Health Statistics (NCHS) median weight-for-age and length-for-age and less than -2 SD of the NCHS median weight-for-length. There were no differences between rice absorbers (peak hydrogen less than 10 ppm above baseline) and rice malabsorbers in the allometric indices (the Ehrenberg index and the Dugdale index) of weight-for-length. Rice-carbohydrate malabsorption was also detected by BHTs in 26.7% of 86 school children (aged 5-15 y), 38.5% of 39 young adults (aged 15-39 y), and 50% of 34 older adults (aged 40-70 y).

Adolescent↗
PubMed1990

Malabsorption of carbohydrate from rice and child growth: a longitudinal study with the breath-hydrogen test in Burmese village children.

Breath-hydrogen tests were performed after a rice meal (3 g cooked rice/kg body wt, equivalent to 1 g carbohydrate/kg body wt) at monthly intervals for 6 mo on 75 village children aged 1-59 mo who were known hydrogen producers. The overall rate for rice-carbohydrate malabsorption was 46.7% (range 37.3-56.0%). Anthropometric measurements were made every 3 mo and growth rates were calculated. Forty-six percent to 59% of children were less than or equal to -3 SD of the National Center for Health Statistics (NCHS) median weight-for-age and length-for-age and less than -2 SD of the NCHS median weight-for-length. Rice malabsorbers (ie, those with hydrogen peaks greater than or equal to 10 ppm above baseline concentrations) in the age groups 36-47 mo and 48-59 mo had statistically significant diminished growth expressed as percent gain in length per annum per child (p less than 0.02). Thus, rice malabsorbers had a deficit in linear growth of 2.7 cm/y (range 2.5-2.9 cm/y) for children aged 36-47 mo old and 1.9 cm/y (range 1.7-2.1 cm/y) for children aged 48-59 mo.

Analysis of Variance↗
PubMed1987

Role of maintenance sucralfate in prevention of duodenal ulcer recurrence.

Fifty-nine patients who had duodenal ulcers that were healed following sucralfate administration in a dose of 1 g four times a day were randomly entered into a double-blind, placebo-controlled, 12-month maintenance study to determine whether sucralfate 1 g twice daily prevents recurrence of duodenal ulceration. Patients were assessed endoscopically at four, eight, and 12 months after healing or earlier if clinical relapse occurred. Of the original 59 patients, 53 showed healing with six weeks of therapy, and the remaining six patients required 10 weeks of treatment. Nine patients were subsequently lost to follow-up because of non-compliance, leaving 50 patients for the analysis, 24 who received sucralfate and 26 who received placebo. There were 10 ulcer recurrences in the sucralfate group and the ulcers in 14 (58 percent) patients remaining healed at the end of 12 months. In contrast, there were 21 recurrences in the placebo group with the ulcers in five patients (19 percent) remaining healed at 12 months. Patients who received placebo experienced recurrence more quickly than those who received sucralfate and there was no difference between the two groups in terms of symptomatic and asymptomatic recurrence. There was no alteration in serum aluminium and phosphate levels throughout the study. Smoking seemed to have no adverse effect on recurrence once initial healing had been achieved. Sucralfate is, therefore, an effective and safe maintenance treatment for duodenal ulcer disease.

Aluminum↗
PubMed1987

The effect of protein deficiency on systemic release of rat mucosal mast cell protease II during Nippostrongylus brasiliensis infection and following systemic anaphylaxis.

Serum rat mucosal mast cell protease II (RMCPII) was measured in protein-deficient rats to assess mucosal mast cell (MMC) activation during primary infection with the nematode, Nippostrongylus brasiliensis, and during systemic anaphylaxis produced by Nippostrongylus antigen in immune animals. In the first study, serum RMCPII increased 4-fold by day 15 after infection. By day 20, serum RMCPII continued to rise in protein-deficient animals, but decreased in nutritionally normal animals. This was associated with impaired worm rejection in protein-deficient rats. During systemic anaphylaxis, serum RMCPII was elevated in three groups of protein-deficient rats on 6%, 8% and 10% low protein diets and in nutritionally normal rats. All protein-deficient rats exhibited 3 to 7-fold less mucosal permeability of the small intestine to Evan's blue dye injected intravenously compared to nutritionally normal animals following anaphylactic stimulation. These results demonstrated that MMC are activated during infection in protein deficiency, and suggest that reduced MMC function does not explain delay in worm expulsion. Impaired mucosal anaphylaxis in protein deficiency could not be attributed to a failure of MMC response.

Anaphylaxis↗
PubMed1986

Blood loss during Nippostrongylus brasiliensis infection in the rat.

Faecal blood loss was measured during Nippostrongylus brasiliensis infection in the DA rat using 51Cr-labelled red blood cells (r.b.c.s). In an initial study, faecal blood loss was measured on day 7 of primary infection with 3000 larvae administered subcutaneously (s.c.), and found to be 0.03 ml/24 h in uninfected animals and 0.14 ml/24 h in infected animals. In a further experiment, blood loss was measured on the day before infection and for 13 days after primary s.c. infection with 5000 larvae. Faecal blood loss was 0.05 ml/24 h or less until day 3, began to rise from day 5, reached a peak of 0.51 ml/24 h on day 8, and fell until day 13. This was closely associated with the rise and fall of the pooled faecal egg count. Direct worm count confirmed a high worm burden on day 7 and expulsion by day 14. The effect of the worm burden on the haemoglobin concentration (Hb) was measured in a further experiment and showed a fall in Hb with a mean worm burden of 726 compared to that of 47 or 284 worms. The study concluded that there is minimal background blood loss in uninfected rats but that infection with N. brasiliensis is a cause of intestinal blood loss and this is associated with a fall in Hb concentration that is dependent on the worm burden.

Analysis of Variance↗
PubMed1986

The effect of methionine and protein deficiency in delaying expulsion of Nippostrongylus brasiliensis in the rat.

Three protein-deficient diets containing 5%, 6%, or 7% casein, with and without 0.3% methionine supplementation, were fed to Wistar rats from weaning for 6 wk. Animals were infected subcutaneously with 1500 larvae of Nippostrongylus brasiliensis and killed after 14 days when nutritionally normal animals have expelled more than 97% of the worm burden. There was a delay in worm expulsion that was related to both the protein content (p = 0.0006) and to methionine content (p less than 0.0001). Methionine supplementation significantly reduced the worm burden in animals fed the 7% protein diet from a geometric mean of 32.4 to 5.2 (p = 0.0408) and in rats fed the 6% protein diet from a mean of 162 to 8.1 (p = 0.0002) but had no effect in rats on the 5% casein diet. Thus, addition of methionine overcame the adverse effect of protein deficiency in these less severely affected groups.

Animals↗
PubMed1984

Serum pancreatic isoamylase estimation by the inhibitor method as a diagnostic test for chronic pancreatitis.

The diagnosis of chronic pancreatitis is often difficult to establish and may involve invasive diagnostic procedures. Serum pancreatic isoamylase has been estimated by the inhibitor method in controls and in 38 patients with known chronic pancreatitis in order to evaluate its use as a diagnostic test. The mean pancreatic isoamylase in those with chronic pancreatitis (68 +/- 77 IU/l) was significantly lower (p less than 0.005) than in controls (113 +/- 60 IU/l). The diagnostic sensitivity of pancreatic isoamylase was 50% (compared to total amylase 9%) and had a specificity of 95%. Stimulation tests with cholecystokinin and secretin failed to increase the sensitivity of the test. A low value of pancreatic isoamylase strongly supports a diagnosis of chronic pancreatitis and may obviate the need for further investigation.

Adult↗