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Evidence was obtained by the use of alternate semithin-thin serial secretions for light and electron microsocpy that the I cell is the source of CCK PZ. The antibodies used were raised to a synthetic fragment of the mid part (9-20) of the (1-33) CCK-PZ molecule, and were thus free from any contamination with cross-reacting subpopulations of antibodies that might bind to gastrin.

Using specific assays, we studied fibrinolytic activity in plasma and colonic mucosa biopsies of 28 patients with inflammatory bowel disease (IBD) (12 with Crohn's disease, 16 with ulcerative colitis) and 28 control patients without inflammatory bowel disease or colon malignancy. Blood coagulation was studied using standard techniques. In plasma of IBD patients significantly decreased tissue type plasminogen activator activity (t-PA) (p less than 0.02), increased plasminogen activator inhibition (PAI) (p less than 0.01) and fibrinogen (p less than 0.001), and prolonged thrombin time (p less than 0.001) and prothrombintime (p less than 0.001) were found. In colon mucosa the percentage of t-PA to urokinase type plasminogen activator (u-PA) was 80:20% in the control group and 71:29% in the IBD group in non-inflamed mucosa. In inflamed mucosa the plasminogen activator percentage was 55:45%, significantly different (p less than 0.01) from the control group. There was also a significant absolute increase in u-PA activity and decrease of t-PA activity in the inflamed mucosa compared to the control group (p less than 0.001 and p less than 0.01, respectively). Patients with inflammatory bowel disease therefore have significant changes in components of the fibrinolytic and coagulation system both systemically and locally in colon mucosa. These changes might contribute to an increased risk for thromboembolic complications and possibly to the pathogenesis of the colitis and to the local complications such as bleeding.

Vasoactive intestinal polypeptide (VIP)-containing nerves and VIP content of endoscopic rectal biopsies from 47 patients with inflammatory bowel disease and 17 normal controls were examined by immunocytochemistry and radioimmunoassay. Immunocytochemistry revealed a consistent increase in, and abnormal appearance of, VIP nerves in patients with Crohn's disease not only those with rectal involvement but also patients with no histological evidence of rectal disease. Normal control biopsies contained 1.64 +/- 0.39 pmol VIP/mg protein as compared with 3.43 +/- 1.24 pmol VIP/mg protein in tissue from patients with rectal Crohn's disease and 5.37 +/- 1.23 pmol VIP/mg protein in those with Crohn's disease without rectal involvement. Ten of the 17 biopsies examined from ulcerative colitics showed a normal pattern of VIP innervation. Examination of the conventional histology of these biopsies showed that only areas with obvious active proctitis had increased VIP nerves and, unlike the appearance in Crohn's disease, these nerves had a normal morphology. The VIP content of these biopsies was similar to that of the controls; 1.34 +/- 0.37 pmol/mg protein.

Severe watery diarrhoea in a patient with medullary thryoid carcinoma and high calcitonin levels was associated with increased distal ileal flow. Plasma from the patient inhibited small intestinal fluid absorption in dogs without affecting mucosal cyclic AMP levels. When calcitonin was removed from the plasma, the effect in experimental bowel loops was abolished but could be restored on restitution of comparable hormone levels with pure calcitonin. These studies, combined with the failure to find evidence of increased prostaglandin activity in the patient, suggest that circulating calcitonin may be a major cause of the diarrhoea in medullary thyroid carcinoma.

A simple technique for isolating lipids from small pieces of tissue was applied to mucosal biopsies and samples of resected intestine from patients with inflammatory bowel disease. Scanning densitometry of two dimensional chromatograms showed increased concentrations of the membrane associated glycosphingolipid lactosylceramide in Crohn's disease, on comparison with ulcerative colitis (p less than 0.01), or controls (p less than 0.01). This indicates either that normal glycosphingolipid metabolism is altered, or that a novel source of lactosylceramide is present in the inflamed mucosa of patients with Crohn's disease.

Isolated mucosal cells from the human jejunum and stomach, cryostat sections from the jejunum, isolated parenchymal liver cells and lymphocytes were investigated for the presence of apolipoprotien A (apoA). Antisera against purified human apoA-I and apoA-II were raised in rabbits and conjugated with fluorescein-isothiocyanate (FITC). Mucosal cells from jejunum and stomach were isolated with pronase from tissue obtained from operated patients. ApoA-I and apoA-II could be demonstrated in isolated mucosal cells as well as in cryostat sections from the jejunum. The fluorescence pattern in isolated jejunal cells was coarse granular. In the radial gel diffusion test the homogenate from mucosal cells of jejunum showed a single precipitation line with anti-apoA-I and with anti-apoA-II, respectively. The reaction was more intensive with anti-apoA-I than with anti-apoA-II. Isolated gastric cells were negative for apoA. Hepatocytes incubated with FITC anti-apoA-I showed a fine granular fluorescence pattern in the cytoplasm. Anti-apoA-II did not react with hepatocytes. There was no evidence for an in vivo fixation of serum-apoA at the surface of isolated mucosal cells from jejunum or isolated hepatocytes. The results support the hypotheses that in man apoA is synthesised in the epithelial cells of the small intestine and in parenchymal liver cells.

VIP-, substance P- and met-enkephalin-containing innervation of the human gastroduodenal mucosa and Brunner's glands was studied by immunocytochemistry on whole mount tissue preparations. A dense VIP-containing nerve supply was found around fundic and pyloric glands, while the few and scattered substance P-immunoreactive fibres tended to run across the full thickness of the gastric mucosa. In the duodenum, both VIP and substance P were present in a striking nerve network in the villi as well as in the muscularis mucosae and around blood vessels. Both peptides were also immunostained in nerve bundles and neuronal perikarya between the lobules of Brunner's glands, while only very few fibres reached the proximity of acinar cells. Met-enkephalin-immunoreactivity was detected in a small number of nerve fibres, virtually confined to the basal parts of the mucosa and to the duodenal submucous plexus.

The distribution of vitamin B12 R-binder in the human digestive tract was studied using an indirect immunoperoxidase technique. Positive staining for R-binder was found in the mucous cells and ductal epithelial cells of the salivary glands and the oesophageal glands. In normal gastric mucosa, no positive staining for R-binder was found, but in the area with intestinal metaplasia, the columnar epithelial cells and goblet cells showed positive staining. Epithelial cells of the gallbladder, intrahepatic bile ducts and pancreatic ducts were also positive for R-binder. In the small intestine and colon, R-binder was found in the columnar epithelial cells and goblet cells. The measurement of unsaturated vitamin B12 binding capacity and cobalamin content in the extracts from intestinal mucosa also indicated the presence of R-binder in the intestinal mucosa.

The mucosal concentrations of seven regulatory peptides and the density properties and integrity of their storage granules have been studied in mucosal biopsies from the human jejunum in eight gastrointestinal disease states and compared with normal controls. In diseases with associated mucosal inflammation (coeliac disease, Crohn's disease with jejunal involvement, postinfective tropical malabsorption, and common variable immunodeficiency) there was a selective increase in fragility of the gastric inhibitory polypeptide (GIP) and somatostatin storage granules. The gastrin, motilin, enteroglucagon, secretin, and vasoactive intestinal polypeptide granules had normal properties in these conditions. In diseases in which diarrhoea occurred in the absence of changes in jejunal mucosal histology (irritable bowel syndrome, pancreatic insufficiency, jejuno-ileal bypass for morbid obesity, and purgative abuse) there were no abnormalities of the storage granules. Increased mucosal concentrations of all peptides except vasoactive intestinal polypeptide (VIP) were found in coeliac disease and selective increases of VIP found in Crohn's disease, motilin in the irritable bowel syndrome and gastrin and GIP in pancreatic insufficiency. It is suggested that the storage granule abnormalities in the diseases with abnormal mucosal histology are secondary to the inflammatory changes.

The presence of food within the small intestinal lumen promotes mucosal cell proliferation. To define the trophic role of triglycerides, three groups of eight female Wistar rats were isocalorically fed for four weeks with either Vivonex, or Vivonex with 50% calorie substitution with an essential fatty acid mixture, or Vivonex with 50% calorie substitution with a saturated fatty acid mixture. Although Vivonex caused greater body weight gain, both essential fatty acids and saturated fatty acids increased small intestinal weight, mucosal weight, protein and DNA overall, and in each of three intestinal segments (proximal, middle and distal), compared with Vivonex. Mucosal indices were similar for essential fatty acids and saturated fatty acids. These results show that triglycerides, regardless of essential fatty acid content, are trophic to the rat small intestinal mucosa.

This study was undertaken to determine the influence of somatostatin on the growth of gastric, duodenal, and pancreatic tissue in rats placed on liquid diet. In the first part of the study animals were fed an elemental liquid diet for 10 days and then killed, and the growth of the oxyntic gland area of the stomach, 2 cm segments of duodenum and pancreatic tissue was determined. Feeding an elemental diet caused a decrease in organ weight, nucleic acid contents and serum gastrin level. Subsequent addition of pentagastrin prevented this reduction in organ weight and RNA and DNA contents while somatostatin failed to affect the decrease in growth parameters or serum gastrin level in tests with or without addition of pentagastrin. In a second part of the study, sham operated and antrectomised rats were used. Antrectomy caused a significant decrease in serum gastrin concentration and resulted in a significant reduction in the weight and RNA and DNA contents of the tissue tested. As in liquid diet, subsequent administration of pentagastrin prevented the reduction in the growth parameters both in tests with and without somatostatin. These results suggest that somatostatin inhibits the growth of the gastroduodenal mucosa by a mechanism involving, at least in part, the suppression of gastrin release.

During a prospective study lasting 3.5 years flow cytometric DNA analysis was evaluated as a possible predictor of dysplastic and malignant lesions in longstanding ulcerative colitis. Fifty three patients with total ulcerative colitis (mean disease duration of 22 years) were regularly colonoscoped. Biopsies of colonic mucosa were analysed by flow cytometric technique and were also assessed histologically. Findings of abnormal DNA pattern (aneuploidy) were compared with findings of dysplasia. Five patients (9%) had aneuploidy, four of those at repeated colonoscopies. Four of those patients also had various degrees of dysplasia. In one patient aneuploidy preceded the finding of dysplasia and in another aneuploidy preceded a well differentiated adenocarcinoma, grade Dukes' A subsequently found at surgery. Four additional patients had dysplasia, all in connection with macroscopic lesions, but were diploid. It is suggested that flow cytometric DNA analysis in long standing ulcerative colitis may be helpful in addition to histopathology in the detection of potential malignancy in ulcerative colitis.

Tissue concentrations of 5-HT have been measured in the duodenal mucosa of adults and children with coeliac disease and were found to be significantly higher than those from a control group. This finding may be associated with hyperactivity or hyperplasia of enterochromaffin (EC) cells in the duodenum of patients with coeliac disease and could also be directly related to described abnormalities of 5-HT metabolism in this disease.

The long chain fatty acid composition of phospholipids in colonic mucosa was determined by high performance liquid chromatography in nine patients with active ulcerative colitis and eight healthy controls. The arachidonic acid composition was 12.5 +/- 1.4 mol % (mean +/- 2 SEM) in the inflamed colonic mucosa from the patients with active ulcerative colitis and 6.8 +/- 1.2 mol % in the intact mucosa from healthy controls (p less than 0.001). In the inflamed colonic mucosa, oleic acid and palmitoleic acid were concomitantly decreased (p less than 0.001 and p less than 0.02, respectively), while docosahexaenoic acid was increased (p less than 0.05). Histopathological examination showed that there was a three fold increase in the cell density of inflammatory infiltrate in the lamina propria of the inflamed colonic mucosa (p less than 0.001). The cell density of inflammatory infiltrate correlated with the arachidonic acid composition of phospholipids in colonic mucosa (r = 0.89, p less than 0.005). These findings indicate that inflammation alters the long chain fatty acid composition of phospholipids in colonic mucosa. The observed increase in the arachidonic acid composition of phospholipids in inflamed colonic mucosa may contribute to the enhanced arachidonic acid metabolism in patients with active ulcerative colitis.

The subclass distribution of IgA producing cells was determined by paired immunofluorescence staining in colonic specimens from 10 patients with ulcerative colitis and eight with Crohn's disease. Compared with normal colonic mucosa, the percentage of IgA1 immunocytes showed a striking increase in both disorders. The proportion of mucosal IgA1 cells was significantly higher (p less than 0.05) in ulcerative colitis (median, 71.2%) than in Crohn colitis (median, 56.9%). Within each category of specimens no significant differences were noted between luminal and basal mucosal zones. The submucosal proportion of IgA1 cells was, however, significantly higher than the mucosal one in both ulcerative colitis (median, 89.1%; p less than 0.002) and Crohn colitis (median, 91.8%; p less than 0.005). The mucosal shift towards IgA1 production paralleled the magnitude of the submucosal IgA1 cell proportion in individual tissue samples. Taken together with the previously reported dramatic increase of local IgG production (particularly observed in the submucosa and basal parts of the mucosa), our findings indicated that there is an influx and/or proliferation of B cells representing systemic secondary immunity in the lesions of both diseases.

Studies of the expression of selected genes within the intestinal mucosa will provide important new information about physiologic pathological processes that effect mucosal growth, differentiation, and function. To study gene expression in the gut, we developed a method to obtain sufficient undegraded RNA from human endoscopic intestinal biopsy specimens for Northern and slot blot analysis. To verify the method, we examined the differential expression of HLA class II genes in small intestinal mucosa. Levels of RNA transcripts for HLA-DR, -DP, and -DQ alpha and beta chains were assessed in freshly isolated endoscopic intestinal mucosal biopsy specimens and compared with levels in Epstein-Barr virus transformed B cells from the same individuals. Sufficient undegraded cellular RNA with distinct 28S and 18S ribosomal bands could be obtained from as few as two 2-3 mm endoscopic biopsies. Using chain and locus specific cDNA probes, HLA-DR, -DP, and -DQ subregion genes were shown to be expressed in intestinal mucosa, with the relative magnitude of RNA transcripts being DR greater than DP greater than DQ. The same hierarchy of expression was seen for EBV-transformed B cell lines. This method, in conjunction with the polymerase chain reaction for amplifying specific RNA transcripts and in situ hybridisation methods for the cellular localisation of RNA transcripts, will enable studies on the regulation of gene expression in the intestinal mucosa.

Colonic tissue was taken at operation from 10 patients with active ulcerative colitis and three patients with uncomplicated diverticular disease but with severe symptoms. Levels of kininogen, kallikrein, and kallikrein precursor were measured in blood-free tissue samples. In normal colon tissue a kininogen occurred in the muscle and none was detected in the mucosa. Kallikrein and its precursor were found in mucosa but not in muscle. In acutely inflamed tissue from ulcerative colitis patients relatively high levels of active kallikrein were detected in the underlying colonic muscle. There was little change in the level of kallikrein in inflamed mucosa or of kininogen in the muscle of these patients. No kallikrein was found in colonic muscle from patients with diverticular disease and the mucosal kallikrein level in these patients was unchanged. The findings suggest a mechanism for the formation of kinins in the wall of the colon which is present in ulcerative colitis but not in diverticular disease.