The role of the pancreas in vitamin B 12 absorption: studies of vitamin B 12 absorption in partially pancreatectomized rats.

The effect of partial pancreatectomy (80-90%) on vitamin B(12) absorption was studied in the rat. The absorption of 5 ng of (57)Co-labeled vitamin B(12) was significantly reduced from 70 +/-2.5% (mean +/-SE) in control and sham-operated rats to 32 +/-2.6% in partially pancreatectomized rats. Hog pancreatic extract (0.17 g/kg) improved vitamin B(12) absorption from 30.0 to 61.0% in partially pancreatectomized rats but did not alter vitamin B(12) absorption in control rats. Chloramphenicol did not enhance vitamin B(12) absorption in partially pancreatectomized rats with pancreatic extract-improved vitamin B(12) malabsorption. The partially pancreatectomized rats with pancreatic extract-improved vitamin B(12) malabsorption were sacrificed and the stomach and small bowel studied in vitro to further define the pathogenesis of the vitamin B(12) malabsorption. Rat gastric intrinsic factor stimulated vitamin B(12) uptake by intestinal sacs prepared from partially pancreatectomized rats 3.1-fold. Gastric intrinsic factor prepared from partially pancreatectomized rats was as effective in promoting vitamin B(12) uptake by rat intestinal sacs as intrinsic factor prepared from control rats. These data indicate that partially pancreatectomized rats develop an abnormality in the absorption of labeled vitamin B(12) which can be corrected by pancreatic extract. The vitamin B(12) malabsorption is due to neither an alteration in gastric intrinsic factor activity nor an impairment of the intrinsic factor-vitamin B(12) receptor in the intestine. It is suggested that in the partially pancreatectomized rats the intrinsic factor-vitamin B(12) complex exists in a form which is not available for absorption.

Differential permeability of the proximal and distal rabbit small bowel.

The permeability of the proximal and distal rabbit intestine for two to six carbon polyhydric alcohols was compared. Intestinal segments were mounted in chambers that permitted the measurement of the unidirectional flux across the brush border membrane. For both proximal and distal intestine, the permeability for a series of polyhydric alcohols decreased with increasing size. The proximal intestine was more permeable for four, five, and six carbon polyhydric alcohols than distal intestine. This regional permeability difference can be attributed to variations in the permeability characteristics of the brush border specifically. The uptake of alcohols was nonsaturable and was not inhibited by phlorizine or n-ethylmaleimide. The results are compatible with the concept that the brush border membrane has properties similar to artificial porous membranes and that the equivalent radius of the pores of the proximal intestine exceeds that of the distal gut.

Trypsin-like nature of the pancreatic factor that corrects vitamin B12 malabsorption associated with pancreatic dysfunction.

Hog pancreas was subfractionated and assessed for its ability to correct vitamin B(12) malabsorption in patients with pancreatic dysfunction and in rats with partial pancreatic extirpation. The constituent obtained from the pancreas that increased vitamin B(12) absorption in both humans and rats was soluble at 50,000 g, heat labile, acid stable, and approximately 20,000-25,0000 in molecular weight. The active subfractions contained tryptic and chymotryptic but no amylase or lipase activity. Thrice-crystallized trypsin corrected the vitamin B(12) malabsorption in both patients with pancreatic insufficiency and in rats with subtotal pancreatectomy. These data indicate that pancreatic proteolytic enzymes-in particular, trypsin-are necessary for optimal vitamin B(12) absorption.

Effect of diet upon intestinal disaccharidases and disaccharide absorption.

The administration of a carbohydrate-containing diet for 24 hours to rats previously fasted for 3 days led to a twofold increase in total intestinal sucrase and sucrase specific activity. The specific activity of maltase was similarly increased, but lactase activity was unaffected. The sucrose-containing diet led to a greater increase in sucrase than maltase activity, whereas the converse was true of the maltose-containing diet. A carbohydrate-free isocaloric diet led to a slight increase in the total intestinal sucrase, but sucrase specific activity was unchanged. Assay of sucrase activity of mixed homogenates from casein-fed and sucrose-fed rats or fasted and sucrose-fed animals yielded activities that were additive. The Michaelis constant (Km) of the enzyme hydrolyzing sucrose was similar in the fasted, casein-fed, and sucrose-fed rats. The maximal velocity (Vmax) was twice greater in sucrose-fed as compared to casein-fed or fasted rats, suggesting an increased quantity of enzyme subsequent to sucrose feeding. Adrenalectomized rats maintained on 1.0% salt intake had sucrase and maltase levels comparable to those of controls. Steroid administration did not significantly increase their activities. The response to sucrose feeding was similar in both control and adrenalectomized rats, indicative of the absence of steroidal control on sucrase and maltase activity in the adult animal. Studies using intestinal ring preparations indicated that sucrose hydrolysis by the intact cells proceeded more rapidly when animals were fed sucrose. Additional corroboration of the physiologic significance of the increased enzyme levels in homogenates was afforded by intestinal perfusion studies. Sucrose hydrolysis increased twofold and fructose absorption fourfold in animals fed sucrose when compared to either fasted or casein-fed rats.

Limited weight losses with a gastric balloon.

An evaluation of the Garren-Edwards gastric bubble in the treatment of obesity was done. Several clinical trials have compared the effects of behavior therapy with and without the bubble, but the effects of the bubble alone have not been previously evaluated. Ten obese women averaging 91% overweight received the bubble without adjunctive therapy during a 12-week treatment period. Frequent psychological and laboratory measures as well as weight were obtained during the study to explore the possible mechanisms of the bubble's effect and its side effects. Mean weight change was -2.5 kg, with a range of -8.8 to +1.6 kg. Four patients lost more than 3.5 kg, three lost less than 3.5 kg, and three gained weight. The Garren-Edwards gastric bubble alone does not appear to provide significant benefit to most obese patients.

A multicenter placebo-controlled clinical trial of oral metoclopramide in diabetic gastroparesis.

Metoclopramide tablets were compared with placebo in the treatment of gastrointestinal symptoms in 40 patients with diabetic gastroparesis. Results of a 3-wk double-blind study indicate that metoclopramide at a dosage of one 10-mg tablet four times daily reduced nausea, vomiting, fullness, and early satiety and improved meal tolerance better than placebo. Statistically significant differences were noted for nausea and postprandial fullness. Mean gastric emptying assessed by radionuclide scintigraphy was significantly improved in the metoclopramide-treated group when compared with their baseline result. Metoclopramide is an effective agent for improving the upper gastrointestinal motor function in diabetic patients with gastroparesis.

Distinction between dysplasia-associated lesion or mass (DALM) and adenoma in patients with ulcerative colitis.

Polyps with epithelial dysplasia in ulcerative colitis (UC) represent either dysplasia-associated lesions or masses (DALMs) or sporadic adenomas. DALMs are frequently associated with associated carcinoma and are an indication for colectomy. Removal of the polyp is treatment of choice for sporadic adenomas. Differentiating between these 2 lesions is not always easy. The goal of this study was to distinguish DALMs from adenomas in patients with UC on a genetic basis. We evaluated genetic alterations in DALMs and compared them with a previously published set of dysplastic polyps in patients with UC that were considered adenomas for the following reasons: (1) polyps were located outside of current active disease; (2) polyps had histological features of sporadic adenomas; and (3) patients displayed a uneventful follow-up after polypectomy (UC-adenomas). In addition, adenomas not associated with UC were studied. Genetic alterations on chromosome 3p were assessed for the markers D3S1766, D3S2409, and D3S2387. LOH with or without microsatellite instability was found in 70%, 37%, and 57% of cases of DALM, respectively. In contrast, UC-adenomas lesions exhibited genetic alterations in 8.3%, 11.7%, and 15.3% for the respective markers. Spontaneous adenomas exhibited genetic alterations in 10.5%, 7.1%, and 0% of cases, which were not significantly different from the UC-adenoma results. These results indicate that UC-adenomas are genetically and biologically similar to sporadic adenomas and that UC-adenomas may biologically represent sporadic adenomas, supporting on a genetic basis the criteria chosen to diagnose adenomas in UC. Genetic markers on chromosome 3p may be useful in the differential diagnosis between DALM and UC-adenomas.

Alpha 1-antitrypsin levels predict mortality from ethionine-induced pancreatitis in mice.

Experimental pancreatitis can be induced by an ethionine-containing, choline-deficient diet in mice. We investigated the role of circulating alpha 1-antitrypsin in this model using two strains of mice: ICR and C57BL-6. A 50% reduction in circulating alpha 1-antitrypsin occurred in all mice by day three of diet exposure. Total protein was reduced by only 9% and albumin was unchanged. Female mice of both strains had significantly lower alpha 1-antitrypsin levels than male mice prior to and after diet exposure. This was associated with significantly greater mortality in both female strains. Interstrain comparisons showed a significantly higher mortality in the C57BL-6 females (100%) compared to the ICR females (58%); this corresponded to significantly lower alpha 1-antitrypsin levels in C57BL-6 females. Regardless of sex or strain, alpha 1-antitrypsin levels prior to and after diet exposure were significantly higher in mice surviving than in mice dying. We conclude that circulating alpha 1-antitrypsin is a predictor of mortality from diet-induced pancreatitis.

Pouchitis in ulcerative colitis: correlation between predictors from colectomy specimens and clinico-histological features.

Pouchitis after restorative proctocolectomy for ulcerative colitis is usually of ill-defined etiology and is encountered with sclerosing cholangitis, bacterial overgrowth, and ischemia. Recently, appendiceal involvement, ileitis, and fissures in the colectomy specimen have been associated with short- and long-term development of pouchitis. To corroborate these recent findings, the histology of 40 colectomies (70% males; mean age 46.3 years, age range 20-70 years; mean follow-up period 3.7 years, range 1-13 years) with yearly follow-up biopsies was correlated with pouchitis and clinical symptoms. Appendicitis, fissures, and ileitis were present in 47, 45 and 5% of the patients, respectively. Pouchitis in patients with appendicitis or with fissures was noted in 44 and 50% at first biopsy and in 70 and 58% during follow-up (p = NS). Of the patients without appendicitis or without fissures, 33 and 33% demonstrated pouchitis at the first biopsy and 30 and 55% during follow-up (p = NS). Clinico-histological correlation revealed normal/near-normal biopsies with the lowest clinical severity score in 77% and with the highest clinical score in 43% (p < 0.025). The histological findings of appendiceal involvement, fissuring ulcers, and ileitis in colectomies for ulcerative colitis do not correlate with the finding of pouchitis in early or late pouch biopsies. A high clinical suspicion score is frequently not correlated with significant inflammation of the pouch.

Characteristics of intestinal glucose secretion in normal and diabetic rats.

A method was developed to characterize and quantitate the transfer of glucose from the plasma to the intestinal lumen. In normal rats, there was a linear correlation between the blood glucose concentration and the rate of appearance of plasma glucose into the intestinal lumen perfused with Krebs-Ringer buffer (r = 0.88, P less than 0.01). Intestinal perfusion with buffers containing either mannitol, glucose, or phlorizin significantly increased the recovery of secreted glucose compared with plain buffer. Rats perfused with buffer containing mannitol or those undergoing plasma volume expansion with dextran demonstrated a change in water movement from net absorption to secretion coupled with a significant increase in glucose secretion. During luminal perfusion with a buffer containing 21 mM glucose, glucose secretion represented 14% of the net glucose absorption rate. Intestinal perfusion with phlorizin gave the highest measured recovery of glucose, probably by blocking active reabsorption of secreted glucose. A series of simultaneous perfusions performed in the jejunum and ileum revealed similar rates of glucose transfer in both segments of intestine. Measurement of glucose secretion in rats with streptozotocin diabetes gave the highest values for the plasma-to-lumen movement of glucose. Treatment with insulin reduced the blood sugar and glucose transfer rate. These data demonstrate that glucose moves bidirectionally across the rat intestine, and its secretion is a passive process.

Cancer risk in patients with inflammatory bowel disease.

Patients with inflammatory bowel disease (IBD) are at increased risk for developing cancer of the gastrointestinal tract, particularly colorectal cancer. Because of the relative rarity of IBD in the general population, it has been difficult to quantify this risk. Efforts to reduce the risk have included both prophylactic surgery and endoscopic screening programs. Because of the potential impact on quality of life and life expectancy, the optimal strategy for reducing this risk has not been defined. This article reviews the current literature relating to the risk of cancer for patients with IBD and methods to reduce this risk.

Direct and indirect effects of dextrose and amino acids on gut mass.

Oral intake of an elemental diet maintains small intestinal mucosal mass compared to the atrophy seen after intravenous infusion of the same diet. The greatest difference in intestinal mass occurs in the proximal bowel and is thought to occur because of rapid absorption in the proximal small bowel. This study was designed to determine the effects of the individual components of the elemental diet and their site of administration within the small bowel on small intestinal mass. Rats were maintained on intravenous alimentation and the proximal gut (by intragastric infusion) or the ileum was continuously infused with equal volumes of 30% dextrose, 5% dextrose, 5% amino acids, saline, or 30% mannitol. After 1 week of combined intravenous alimentation and gut infusion, the rats were killed and parameters of small intestinal epithelial mass were determined sequentially for the entire bowel. Although saline- and mannitol-infused controls did not differ from uninfused intravenously fed rats, proximal infusion of 30% dextrose reproduced the effects of a complete elemental diet. Proximal infusion of amino acids but not 5% dextrose had a limited effect on the duodenum and jejunum. Ileal infusion of 30% dextrose led to local hyperplasia of the site of infusion and in addition produced hyperplasia of the proximal gut. Ileal amino acid infusion, but not 5% dextrose infusion, led to local ileal hyperplasia. We conclude that: (1) intraluminal dextrose and amino acids have direct effects in maintaining gut mass (2) the gut is more responsive to amino acids compared to 5% dextrose, and (3) ileal 30% dextrose infusion leads to remote effects in the proximal gut, perhaps mediated by hormonal or neurovascular factors.

Small-bowel resection. Oral intake is the stimulus for hyperplasia.

Small-bowel resection leads to hyperplasia of the residual small intestine, However, the factors initiating small-bowel hyperplasia are not clearly understood, although oral intake either by direct contact with the small bowel or via hormonal or neurovascular factors has been suggested as the major stimulus. In order to determine whether oral intake is an obligatory prerequisite for small-intestinal hyperplasia, we compared rats one week after undergoing a 70-cm proximal intestinal resection with sham-operated animals. Resected, orally fed rats demonstrated small-intestinal hyperplasia, whereas resected and sham-operated intravenously alimented rats did not. There were no differences in gut weight, mucosal weight, mucosal protein, or DNA between resected or sham-operated intravenously alimented rats. These data provide direct experimental proof that oral intake is a necessary stimulus for small-intestinal hyperplasia after resection.

Alkaline phosphatase production by periosteal cells at various oxygen tensions in vitro.

A mammalian periosteal cell culture system was developed to investigate the metabolic response of fresh calf bone periosteal cells to various oxygen tensions in vitro. Two predominant cell phenotypes were seen in the culture system. A rapidly proliferating mat of alkaline phosphatase-negative cells supported the growth of overlying clusters of alkaline phosphatase-positive cells. The appearance and subsequent population growth of the alkaline phosphatase-positive cells correlated directly with increases in enzyme activity on biochemical assay. Alkaline phosphatase production was optimal at lower oxygen tensions (5%, 9%), which approximated capillary pO2. In addition, the preconfluence oxygen environment was more critical to the final expression of the enzyme activity than the postconfluence environment. The mechanism of the environmental regulation of alkaline phosphatase gene expression at various oxygen tensions is not known. Periosteal cells were highly sensitive to oxygen tension and expressed alkaline phosphatase enzyme activity at oxygen levels approximating capillary rather than atmospheric pO2.

Production of chemoattractant by Helicobacter pylori.

Helicobacter pylori is present in the antral region of the stomach in a majority of patients with gastritis type B. The specific mechanism whereby the organism participates in the development of disease remains uncertain. Since the organism is not invasive, we postulate that H. pylori produces a chemoattractant that recruits inflammatory cells to the antral region of the stomach. H. pylori was grown under microaerophilic conditions at 37 degrees C for 72 hr in Brucella broth containing 1% fetal bovine serum. Culture supernates were harvested after removal of organisms by centrifugation and filtration. The putative chemoattractant in culture supernates as well as that which might be present endogenously in the growth medium (negative control) was assayed against human neutrophils (PMN) in modified Boyden blind-well chambers using 3.0-microns membranes. We found that H. pylori supernates are chemotactic and showed up to 130% activity when compared to the positive chemoattractant control (zymosan-activated serum, a source of C5a). Minimal activity was observed with virgin growth medium. The chemoattractant activity is proportional to the number of colony forming units (CFU) of H. pylori. Preliminary characterization of the activity shows that the chemoattractant is stable in a boiling water bath for 15 min, activity is lost within 1 hr in acid or alkali, and the chemotactic factor has an approximate molecular weight of 8500 daltons. The factor has no amino-sugar and is negative for the lipid A portion of lipopolysaccharide.(ABSTRACT TRUNCATED AT 250 WORDS)

Mucinous cystadenoma: pitfalls of differential diagnosis.

Cystic neoplasms of the pancreas often are difficult to differentiate from pseudocysts. It has been proposed that a history of clinical pancreatitis, elevated serum pancreatic enzymes, elevated cyst fluid amylase, and a communication with the pancreatic duct suggest the diagnosis of a pseudocyst. We report the case of a young woman who presented with a cystic mass in the pancreas and was thought to have a pseudocyst because of the above; at surgery, a mucinous cystadenoma was documented. The pitfalls of differentiating neoplastic cysts of the pancreas from pseudocysts are discussed.

Shoulder after surgery: MR imaging with surgical validation.

To assess the accuracy of magnetic resonance (MR) imaging in the evaluation of the shoulder after surgery, MR examinations were performed in 31 patients before repeated surgery, and MR findings were correlated with the subsequent operative findings. In addition, the MR findings associated with prior surgery were reviewed, including altered structure of the acromion, soft-tissue metal artifacts, a surgical trough in the humeral head, nonvisualization of the subacromial-subdeltoid fat stripe, and intermediate signal intensity within the substance of the rotator cuff on images obtained with all pulse sequences. The MR criteria for full-thickness tears in the shoulder after surgery are the presence of fluidlike signal intensity on T2-weighted images that extends through an area of the rotator cuff or the nonvisualization of a portion of the rotator cuff. With use of these criteria, six of seven full-thickness rotator cuff tears were identified at MR imaging, with an accuracy of 90%. Partial cuff tears were indistinguishable from repaired tendons. Findings at MR imaging were 74% accurate concerning the presence of impingement.

Inflammatory bowel disease is not associated with an increased risk of lymphoma.

BACKGROUND & AIMS: Previous studies of the risk of lymphoma in inflammatory bowel disease patients have provided conflicting results. This study examines the risk of Hodgkin's and non-Hodgkin's lymphoma among patients with inflammatory bowel disease. METHODS: The authors performed a retrospective cohort study using the General Practice Research Database. Inflammatory bowel disease patients were matched to randomly selected controls on age, sex, and primary care practice. Lymphoma rates were also compared with published age- and sex-specific rates. RESULTS: The study included 6605 patients with Crohn's disease, 10,391 with ulcerative colitis, and 60,506 controls followed for an average of 3.7, 3.9, and 4.4 years, respectively. The incidence of lymphoma was not increased in patients with inflammatory bowel disease (relative risk = 1.20; 95% CI, 0.67-2.06). In subgroup analyses, an increased risk was not observed among patients with Crohn's disease (relative risk = 1.39; 95% CI, 0.50-3.40) or ulcerative colitis (relative risk = 1.11; 95% CI, 0.51-2.19). Compared with inflammatory bowel disease patients not treated with azathioprine or 6-MP, the relative risk of lymphoma among the 1465 inflammatory bowel disease patients treated with these medications (average, 106 mg/day for 2.0 years) was 1.27 (95% CI 0.03-8.20). CONCLUSIONS: Patients with inflammatory bowel disease do not have an increased risk of lymphoma as compared with the general population. Although we cannot completely rule out a modest increased risk of lymphoma with azathioprine or 6-MP therapy, an increased risk was not observed in this cohort.