Biomedical subjects

A B Thomson

Publications and source records attributed to A B Thomson.

At least 289 records · Page 16Linked to original sources

PubMed1984

Vitamin and iron intake in patients with Crohn's disease.

A descriptive study was conducted in 23 male and 24 female adult patients with Crohn's disease to assess nutritional status. The mean daily intake of vitamin B6 and folate by the men and the women and of iron by the women was less than the Recommended Dietary Allowances. However, the range of individual intakes varied widely. According to Nutrition Canada Interpretive Standards, 50% of the female patients had inadequate intakes of iron; 13%, of riboflavin; 21%, of thiamin; and 21%, of vitamin A. The men consumed significantly less vitamin A and folate per 1,000 kcal than the women. Serum folate was the only laboratory parameter that correlated with nutrient intake; it was correlated with dietary folate, vitamin C, vitamin B12, and vitamin B6 intakes in the women only. Serum folate was low in 21% of the men and 26% of the women. Thus, a low serum folate was predictive of a potential risk of nutritional deficiency of folate and of vitamins B6, B12, and C. This study demonstrated that nutrient intake was reduced in some patients and therefore could be a factor contributing to observed nutritional deficiency in Crohn's disease.

Adolescent↗

PubMed1984

Nutrient intake of patients with cystic fibrosis.

Nutrient intake, anthropometric measurements, and pulmonary function were assessed in 26 young adult patients with cystic fibrosis (CF). Mean nutrient intakes, excluding those from vitamins and nutrient supplements, were less than the Recommended Dietary Allowances for folate for men and women and for iron and vitamin B-6 for women. Male cystic fibrosis patients consumed significantly more of 11 of 16 nutrients in comparison with men with Crohn's disease and men with functional gastrointestinal complaints. Female cystic fibrosis patients consumed significantly more of 9 of 16 nutrients than did women with gastrointestinal complaints. The relative body weight was less than 85% of standard in 65% of men and 50% of women with CF. Relative body weight was correlated with variables indicative of airflow obstruction, reduced vital capacity, and hyperinflation of lung volumes.

Adolescent↗

PubMed1984

Acute hemorrhagic pancreatitis and diabetes mellitus following endoscopic retrograde cholangiopancreatography.

Endoscopic retrograde cholangiopancreatography (ERCP) is generally regarded as a safe and useful investigation in the diagnosis and management of diseases of the pancreas and biliary tree. Asymptomatic hyperamylasemia is not uncommon following this procedure, but clinical pancreatitis is rare. The authors report on a 56-year-old man who suffered life-threatening acute hemorrhagic pancreatitis 2 weeks after ERCP was performed for the investigation of abdominal pain. He subsequently had insulin-dependent diabetes mellitus, which was not present at the time of ERCP.

Acute Disease↗

PubMed1983

Intestinal uptake of fatty acids and cholesterol in four animals species and man: role of unstirred water layer and bile salt micelle.

The uptake (Jd) of fatty acids (FA), fatty alcohols (Alc) and cholesterol (C) into the jejunum of rats (R, Rattus norvegicus), rabbits (RAB, Oryctolagus cuniculus), guinea pigs (GB, Cavia porcellus), and hamsters (H, Mesocricetus auratus) was assessed in vitro. Using jejunal discs the Jd of Alc was H greater than R = GP greater than RAB, the Jd of FA was H-RAB greater than R greater than GP, but the Jd of C was R greater than H greater than RAB greater than GP. The Jd of FA was quantitatively and qualitatively different when using jejunal biopsies; in man the Jd of FA into biopsies was greater than in the other animal species, but there was no difference in Jd of FA into normal human jejunal biopsies and those showing severe abnormalities in villus architecture. There are marked species differences in the passive permeability properties of the jejunum and in the effective resistance of the overlying unstirred water layer, but these differences do not explain the species variations in the uptake of cholesterol.

Adolescent↗

PubMed1983

Effect of dietary modification on the enhanced uptake of cholesterol in diabetic rats.

Previous studies have demonstrated an enhanced intestinal uptake (Jd) of nutrients in diabetes mellitus in the rat, and the present studies were undertaken to determine the effect of dietary modifications on the Jd of cholesterol. In control rats, cholesterol Jd was highest in animals fed a low cholesterol diet, and lowest in those fed a high protein diet. Cholesterol Jd was highest in diabetic animals fed a high carbohydrate diet. Cholesterol Jd was higher in diabetic than in control rats only when they were fed the high carbohydrate diet; cholesterol Jd was similar in diabetic and control animals fed a high cholesterol, high protein, or low protein diet, and was lower in diabetic than control rats fed a low cholesterol diet. These changes in cholesterol Jd were not explained by differences in parameters of intestinal structure, weight gain, or food consumption. Thus the differences in cholesterol Jd observed between diabetic and control animals may be modified by varying the composition of the diet, and avoiding a high carbohydrate diet prevents the enhanced Jd of cholesterol in drug-induced diabetes mellitus.

Animals↗

PubMed1983

Effect of dietary modification on the uptake of glucose, fatty acids, and alcohols in diabetic rats.

Nutrient uptake (Jd) is enhanced in diabetes mellitus (DM) in the rat; these studies were undertaken to determine the effect of 2 wk dietary modification on the Jd of fatty acids, fatty alcohols, and glucose. In control (C) rats, fatty acid Jd was lowest with the low essential fatty acid diet, but the incremental change in free energy (integral of delta Fw leads to l) was not affected by the other diets; in DM integral of delta Fw leads to l was lower with the low cholesterol or high carbohydrate diets, and higher with the high cholesterol diet. The effective resistance of the intestinal unstirred layer was assessed from the Jd of lauryl alcohol. In C intestinal unstirred layer was lowest in the high carbohydrate group and highest in the low cholesterol group; intestinal unstirred layer was less in DM than in C only in the rats fed the low cholesterol diet. In C, varying the protein content of the diet was associated with a rise in the value of the maximal transport rate and the Michaelis constant, but a decline in the passive permeability coefficient for glucose. Glucose Jd was increased in DM rats fed a high carbohydrate or a high cholesterol diet; the values of the Kms were similar in DM and C, but the maximal transport rates were higher in the DM than in the C and these values were influenced by dietary modifications. Thus short-term dietary modification influences intestinal unstirred layer, integral of delta Fw leads to l, and the kinetic constants for Jd of glucose in control and diabetic rats.

Animals↗

PubMed1983

Cimetidine for recurrent ulcer after gastric surgery.

Seven of nine patients with ulcers recurring after a variety of gastric operations enjoyed loss of dyspeptic symptoms within 2 days of taking cimetidine, 1,200 mg/day for 6 weeks, and endoscopic confirmation of healing of the recurrent ulcer was established within 6 weeks of therapy. Once ulcer healing had been achieved in these seven patients, symptomatic remission persisted for over 19 months without maintenance therapy with cimetidine, and no complications suggestive of recurrent ulcerations occurred during this period in these seven patients. The eighth patient with a recurrent ulcer after vagotomy and pyloroplasty had symptoms suggestive of a gastric outlet obstruction in association with a bezoar and an elevated fasting serum gastrin concentration; cimetidine failed to heal the ulcer and a partial gastrectomy with Billroth I anastomosis was undertaken. The ninth patient lost his dyspeptic symptoms while on cimetidine, but 1 month after stopping therapy he succumbed to a massive hemorrhage; autopsy revealed a large pyloric channel ulcer. We suggest that cimetidine is helpful for the control of symptoms and the healing of recurrent ulcers after gastric surgery, but that endoscopy be repeated after an appropriate interval while such patients remain on cimetidine to assure that the disappearance of symptoms is truly associated with a lack of peptic ulceration. If the ulceration persists, we believe that cimetidine should be continued for a longer period.

Adult↗

PubMed1983

Gastrin, gastric emptying, and gastroesophageal reflux after ranitidine.

In a double-blind study comparing ranitidine to placebo in the treatment of symptomatic gastroesophageal reflux disease (GERD), we assessed gastric emptying time, gastroesophageal reflux, and gastrin response to food. Mean half-time for gastric emptying, measured using 99mTc-sulfur colloid, was 109 minutes in GERD and 102 minutes in nine healthy asymptomatic controls. This difference was not significant, but one-third of GERD had emptying times of 2 S.D.s beyond the mean for the normal controls. The patients with GERD refluxed an average of 2.3% (0.1-10%) of the isotope in 120 minutes compared with only 0.2% (0.0-0.5%) in control subjects. Reflux scans and gastric emptying times did not change with healing of esophagitis or with symptomatic improvement from ranitidine and antacids. There was no relationship between the percentage of the test dose refluxed into the esophagus and the rate of gastric emptying. The mean fasting gastrin concentration in GERD, 133 +/- 12 pg/ml, was higher than in healthy controls, 93 +/- 10 pg/ml (p less than 0.01). After stimulation with a standard meal, the integrated gastrin response (IGR) was similar in controls and GERD patients, but IGR was significantly higher after 6 weeks therapy with ranitidine. These results suggest that: 1) gastric emptying time may be prolonged in some patients with GERD, 2) basal but not food-stimulated gastrin concentrations may be abnormal in GERD, 3) reflux scans have limited use in the investigation of GERD, and 4) ranitidine therapy is associated with an increase in food-stimulated gastrin concentrations.

Adult↗

PubMed1983

Kinetics of uptake of glucose in rabbit jejunum: influence of sodium, unstirred layers, and passive permeation.

Failure to account for the effect of the unstirred water layer and the contribution of passive permeation will lead to errors in the estimation of the kinetic constants of glucose uptake into the intestine. It is widely accepted that variations in the concentration of sodium in the bulk phase profoundly influence the rate of uptake of glucose in the intestine, but the kinetic basis for this effect remains in dispute. Accordingly, a previously validated in vitro technique was used to assess the effect of Na+ on the uptake of glucose into rabbit jejunum under conditions selected to reduce the unstirred layer resistance. Varying Na+ had no effect on the uptake of lauryl alcohol and therefore on unstirred layer resistance. The passive permeability coefficient for glucose uptake was estimated from the uptake of L-glucose, of D-glucose at 4 degrees C, or in the presence of 1 mM phlorizin or 40 mM galactose. The permeability for glucose increased as Na+ rose. The values of both the maximal transport rate and the Michaelis constant (Km) were influenced by Na+. A linear relationship was noted between Na+ and the maximal transport rate; the value of Km fell as Na+ was increased to 75 mequiv./L, but Km did not decline further with higher values of Na+. These results support the theoretical predictions of the presence of both an affinity and a velocity effect of the sodium gradient on the intestinal transport system for glucose.

Animals↗

PubMed1983

Experimental diabetes and intestinal barriers to absorption.

The unstirred water layer (UWL) and the brush-border membrane represent the major barriers to intestinal absorption. Enhanced uptake of several nutrients has been described in diabetes mellitus, and this study was undertaken in the rat to define whether these absorptive changes are due to alterations in the characteristics of these barriers. Using in vitro techniques the effective resistance of UWL was measured with lauryl alcohol, the rate of uptake (Jd) of which is limited by diffusion across the UWL. At all rates of stirring of the bulk phase, the effective resistance of UWL was less in diabetic than control rats. The Jd of a homologous series of saturated fatty acids (4:0-18:0) and cholesterol was higher than disks of intestine of diabetic than control intestine; this enhanced uptake of lipid could not be demonstrated using intestinal biopsies. The change in incremental free energy of transfer of fatty acid uptake into disks was higher in diabetic than control animals after correction for UWL effects. After correction for UWL, the Michaelis constant for Jd of D-glucose was similar in diabetic and control jejunum, and the greater Jd of glucose in diabetics was due to a higher maximal transport rate (Jmd) and a higher passive permeability coefficient. It is concluded that the enhanced uptake of glucose, fatty acids, fatty alcohols, and cholesterol into diabetic intestine is due to a reduction in the effective resistance of the UWL, an increase in the passive permeability properties of the membrane, and a rise in the Jmd for D-glucose.

Animals↗

PubMed1983

Uptake of bile acids into rat intestine. Effect of diabetes mellitus.

Diabetes mellitus is associated with the enhanced uptake of several nutrients. The purpose of this study was to use an established in vitro technique to examine the uptake of bile acids into jejunum, ileum, and colon of control (CON) and streptozotocin-diabetic rats (DM). When the bulk phase was stirred to reduce the effective thickness of the unstirred layer, the ileal uptake of 1.5-15 mM cholic (C), glycocholic (GC), taurocholic (TC), chenodeoxycholic (CDC), glycochenodeoxycholic (GCDC), and deoxycholic (DC) acid was similar in CON and DM. The relative values of the maximal transport rates (Jdm) were CDC greater than GC greater than GCDC greater than C greater than TC = DC, and similar relative values were observed for the Michaelis constants (Km). The values of Jdm and Km for each bile acid were similar in CON and in DM. In CON and at pH 7.4 an inverse linear relationship was noted between the number of hydrogen bonds in the bile acids and the natural logarithm of the permeability coefficient (Pd) times the square root of the molecular weight of the bile acid. This slope reflected the incremental change in free energy, delta delta Fw leads to I, associated with the uptake of bile acids; the value of delta delta Fw leads to I was similar for jejunum, ileum, and colon of CON, but was lower in jejunum of DM than CON. Thus, DM is associated with a greater relative permeability of the jejunum but not the ileum or the colon to a series of bile acids.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1983

Effect of ranitidine on healing of peptic ulcer: a 2-month study.

A multicenter trial of oral ranitidine 150 mg bid was conducted in 41 patients with duodenal and 30 with gastric ulcers. Patients were randomly allocated in double-blind fashion to 4 wk treatment with either ranitidine or placebo, after which all unhealed patients were given 4 wk on the active drug without breaking the original allocation code. After 4 wk of treatment the healing rate associated with ranitidine was significantly superior to that of placebo in both duodenal and gastric ulcer patients. Further improvement in cumulative healing rates was observed after the 2nd month of the study. After the allocation code was broken and all patients had had the opportunity of up to 8 wk on the active drug, there remained only a single unhealed pyloric ulcer. No serious adverse effects or biochemical abnormalities were observed. Ranitidine is a potent and well-tolerated H2 antagonist. Therapy for 4 or 8 wk is highly effective in the treatment of uncomplicated gastroduodenal ulcer.

Adult↗

PubMed1983

Diet of women with Crohn's and other gastrointestinal diseases.

Our results do not support the assertion that subjects with Crohn's disease consume significantly more sugar than controls or those with ulcerative colitis. A subgroup of patients may consume a high proportion of total kilocalories as sugar. In spite of recommendations to increase their dietary fiber intake, subjects with irritable bowel syndrome did not receive significantly more fiber from food sources. Clearly more research is needed to characterize the sugar and dietary fiber intakes of patients with gastrointestinal diseases.

Adult↗

PubMed1983

Effect of abdominal irradiation on the kinetic parameters of intestinal uptake of glucose, galactose, leucine, and gly-leucine in the rat.

A previously validated in vitro technique was used to determine the effect of abdominal irradiation on the intestinal uptake (Jd) of glucose, galactose, leucine, and gly-leucine in the rat. Three days after 600 rads from a cesium-137 source, there was a rise in the jejunal maximal transport rate (Jdm) and the apparent Michaelis constant (Km*) but a decline in the apparent passive permeability coefficient (Pd*) for glucose. Thereafter, there was a progressive decline in Km* and Jdm but a rise in Pd* for glucose uptake. In the ileum, irradiation was associated with an increased Km* and Jdm and a decreased Pd*. Fourteen days after 600 rads, Jd of leucine into the jejunum was unchanged but Jd of leucine into the ileum was increased because of a higher Pd*. The Jd of leucine from gly-leucine was greater than from leucine alone. The Jd of 0.5 to 10 mM gly-leucine into the jejunum was increased after 600 rads, whereas the greater Jd of gly-leucine into the ileum after irradiation was most marked at 40 mM. Fourteen days after 300 rads, the Jd of glucose and galactose was increased into the ileum, whereas the Jd of leucine was decreased and the Jd of these probes into the jejunum and colon was unchanged; 14 days after 900 rads, the Jd of glucose and galactose was unchanged in each site and the Jd of leucine was reduced in the ileum but not the jejunum or colon.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗

PubMed1982

Use of percollTM in the isolation and purification of rabbit small intestinal brush border membranes.

(1) Intestinal absorption is altered under a variety of circumstances in health and disease and to determine a possible relationship between intestinal absorptive function and intestinal brush border membrane composition, we undertook the isolation and purification of rabbit jejunal and ileal brush borders, to allow further studies of their lipid composition under varied experimental conditions. (2) A modification of an established method (Schmitz, J., Preiser, H., Maestracci, D., Ghosh, B.K., Cerda, J.J. and Crane, R.K. (1973) Biochim. Biophys. Acta 323, 98-112) utilized CaCl2 aggregation and sequential centrifugation followed by purification of the brush border pellet (P2) at 27,000 X g on a PercollTM (Pharmacia) self-forming gradient. The PercollTM was removed by ultracentrifugation for 30 min at 100 000 X g, utilizing a batch rotor in the Beckman airfugeTM. (3) Pure brush border membrane vesicles were obtained and characterized by specific marker analysis and electron microscopy. Comparative marker analyses performed on P2 and final PercollTM preparations from animals showed that the purification achieved was 8-11-fold greater when compared to the original homogenates. Verification of purity was also demonstrated by the absence of DNA and very low levels of Beta-gluconridase and (Na+ + K+)-ATPase in the PercollTM preparations. (4) Comparative lipid analyses of P2 and final PercollTM preparations showed that levels of total phospholipid and free fatty acids were several-fold higher in the PercollTM preparations on a per mg protein basis. (5) A comparison of the activity of enzyme markers and the levels of total free fatty acids in P2 pellets obtained after Cacl2 and MgCl2 aggregation showed that CaCl2 aggregation gave the more consistently reproducible results. (6) Although standard procedures of membrane preparations not involving density gradient separation provide membranes of reasonable purity for the estimation of lipid components, we consider the final purification step of density gradient separation using PercollTM is essential for determining small quantitative changes which might occur in the membrane lipid composition under experimental conditions were intestinal absorptive function is altered.

Alkaline Phosphatase↗

PubMed1982

Comparison of kinetic constants of hexose uptake in four animal species and man.

1. The rate of in vitro uptake of glucose (gl), galactose (gal), 3-O-methyl glucose (MG), and fructose (fr) was determined using jejunal discs of hamster (ham), rat, rabbit (rab) and guinea pig (gp). 2. The maximal transport rates (Jdm) of each hexose were ham greater than rab greater than gp = rat; 3. The Michaelis constants were different for the four sugars; for gl the values were gp greater than rat greater than ham greater than rab. 4. The passive permeability coefficients (Pd) were similar for each sugar, and were greatest in ham and rat, and lowest in rat and gp. 5. The effective resistance of the intestinal unstirred water layer was lowest in ham and highest in gp and rat. 6. There were differences in the kinetic constants for gl estimated using discs and biopsies of jejunum, and the greater uptake into human biopsies than in the other species was due to the higher Jdm and Pd.

Animals↗

PubMed1982

Influence of dietary modifications on uptake of cholesterol, glucose, fatty acids, and alcohols into rabbit intestine.

The role of dietary modifications upon the rate of intestinal uptake of lipids and D-glucose was examined using a previously validated in vitro technique. Rabbits were fed for 6 wk on a control diet, or one containing 2% fat (F), 0.2% cholesterol (C), or 0.2% cholesterol plus 2% fat (CF). The rate of uptake Jd, of glucose into the jejunum and ileum was decreased from higher concentrations of glucose in CF, but was markedly increased in F and C. The Jd of a homologous series of saturated fatty acids into the jejunum was highest in C, intermediate in F and CF, and lowest in the control animals; the differences in Jd were most marked when the bulk phase was stirred to reduce the effective resistance of the intestinal unstirred layer, but the differences in lauric acid uptake persisted even when the bulk phase was unstirred and the effective resistance of the unstirred layer was high. The Jd of fatty alcohols was C greater than CF greater than F at each rate of stirring, and the relative rates of cholesterol Jd were control greater than CF greater than C greater than F. It is proposed that dietary lipid modifications are associated 1) with reciprocal changes in the effective resistance of the intestinal unstirred water layer and the passive permeability characteristics of the intestine; and 2) with alterations in the kinetic constants of the intestinal uptake of glucose; 3) there is a functional heterogenerity of the villus in response to variations in the lipid content of the diet, with quantitatively and qualitatively different changes in the passive uptake of fatty acids, fatty alcohols, and cholesterol. It is concluded that modification of the lipid content of the diet has a complex effect on intestinal membrane function and may affect both active and passive transport processes.

Animals↗

PubMed1982

Influence of sodium on major diffusion barriers to passive intestinal uptake.

Intestinal active transport processes have been shown to be sodium dependent, but the effect of varying the concentration of sodium in the luminal bulk phase on the passive uptake of lipids has not been established. An in vitro technique was used to measure the uptake of fatty acids and alcohols into the rabbit jejunum under conditions of stirring of the bulk phase selected to reduce the effective resistance of the unstirred water layer (UWL). Sodium withdrawal had no effect on the uptake of a homologous series of fatty alcohols, and thus the UWL was not influenced by varying bulk-phase sodium; in contrast, the uptake of a homologous series of short-, medium, and long-chain-length saturated fatty acids (FA) was progressively inhibited by reducing bulk-phase sodium from 145 to 0 meq/l. There was no difference in FA uptake between the use of magnesium chloride and mannitol for maintenance of isotonicity with sodium withdrawal. At each sodium concentration, the uptake of FA rose with increasing FA chain length. The relation between sodium concentration and incremental change in free energy (delta delta Fw leads to 1) was described by a sigmoid-shaped curve. The uptake of cholesterol was also inhibited by reducing sodium in the bulk phase. In summary, varying bulk-phase sodium has no effect on UWL, and the influence of sodium on the uptake of FA is mediated by altering delta delta Fw leads to 1 and therefore the physicochemical properties of the brush-border membrane.

Animals↗