| 1. |
- Nilsson, Ola, 1957, et al.
(författare)
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Praomys (Mastomys) natalensis: a model for gastric carcinoid formation.
- 1992
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Ingår i: The Yale journal of biology and medicine. - 0044-0086. ; 65:6
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Tidskriftsartikel (refereegranskat)abstract
- The gastric carcinoid tumors of Praomys (Mastomys) natalensis have been reviewed with respect to histogenesis, development, biochemistry, and morphological properties. Multicentric gastric carcinoids frequently develop in the oxyntic mucosa of aging Mastomys. The development of these tumors can be significantly enhanced by drug-induced hypergastrinemia, e.g., histamine2-receptor blockade. Spontaneous and drug-induced gastric carcinoids are endocrine in nature, as evidenced by their argyrophilic staining properties and chromogranin A content. They are also rich in histidine decarboxylase activity and produce large amounts of histamine, although other hormones, such as peptide YY and enteroglucagon, have also been demonstrated in these tumors. Ultrastructurally, gastric carcinoids are composed of tumor cells with typical secretory granules resembling those of enterochromaffin-like (ECL) cells. A close examination of the gastric carcinoids in Mastomys reveals striking similarities with gastric carcinoids developing in humans suffering from chronic atrophic gastritis type A or from the Zollinger-Ellison syndrome in combination with multiple endocrine neoplasia type 1 (MEN-1). Both these conditions are associated with hypergastrinemia and a higher risk for developing multi-centric gastric carcinoids of ECL-cell origin. The Mastomys tumor model therefore appears to be a significant experimental model in which induction and formation of gastric carcinoid tumors can be studied.
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| 2. |
- Wold, Agnes E, 1955, et al.
(författare)
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Resident colonic Escherichia coli strains frequently display uropathogenic characteristics.
- 1992
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Ingår i: The Journal of infectious diseases. - 0022-1899. ; 165:1, s. 46-52
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Tidskriftsartikel (refereegranskat)abstract
- Bacterial factors associated with long-term persistence in the colon have not been defined. Individual Escherichia coli strains in the colonic flora of 13 schoolgirls with asymptomatic bacteriuria were identified by electromorphic typing of chromosomally encoded enzymes and defined as resident or transient. The strains were characterized as to serotype, receptor specificity, and adherence to the human colonic epithelial cell line HT-29. Colonic resident strains expressed P fimbriae, adhered to colonic epithelial cells via a mannose-resistant mechanism, and expressed the uropathogenic serotypes O1, O2, O6, O7, O18, O25, or O75 more often than did the transient strains, which were often nontypeable. The serotype and hemagglutination pattern were generally retained during intestinal carriage, in contrast to the loss of such properties upon prolonged colonization of the urinary tract. P fimbriae with Gal alpha 1----4Gal beta-specific adherence may, in fact, have evolved to increase persistence in the colon.
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| 3. |
- Ahlman, Håkan, 1947, et al.
(författare)
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Aspects on diagnosis and treatment of the foregut carcinoid syndrome.
- 1992
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Ingår i: Scandinavian journal of gastroenterology. - 0036-5521. ; 27:6, s. 459-71
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Tidskriftsartikel (refereegranskat)abstract
- Eight patients with the foregut carcinoid syndrome (two gastric and six bronchial primary tumors) are reported. The patients presented with complex clinical symptoms including ectopic production of adrenocorticotrophic hormone and growth hormone-releasing factors. The most alarming symptoms were facial flush and edema, accompanied by severe bronchoconstriction, which easily was misinterpreted as asthmatic attacks. Conventional bronchodilatory drugs may be potentially dangerous in these patients, in whom combined blockade of histamine receptors and treatment with cortisone and octreotide are recommended. Owing to the patients' age and general condition individualized long-term therapy was instituted. Surgical therapy under optimal protection by drugs can be of substantial value also in patients with advanced disease. One patient with life-threatening hormonal symptoms underwent hyperthermic perfusion of the liver with cytotoxic drugs, resulting in good palliation.
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| 4. |
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| 5. |
- Andersson, K, et al.
(författare)
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Hyperplasia of histaime-depleted enterochromaffin-like cells in rat stomach using omeprazole and a-fluoromethylhistidine
- 1992
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Ingår i: Gastroenterology. - 1528-0012. ; 103:3, s. 897-904
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Tidskriftsartikel (refereegranskat)abstract
- In the rat, gastric histamine is stored mainly in the enterochromaffinlike cells. Gastrin releases histamine from these cells, and long-term hypergastrinemia results in hyperplasia. The effect of sustained hypergastrinemia on histamine-depleted enterochromaffinlike cells was studied by measuring histidine decarboxylase activity and histamine concentrations and by using quantitative histology. Hypergastrinemia maintained for 6 weeks was induced by inhibition of gastric acid secretion with omeprazole (400 mumol.kg-1.day-1) given orally, and histamine synthesis was inhibited for the same length of time with alpha-fluoromethylhistidine (3 mg.kg-1.h-1) given via osmotic minipumps. In rats given omeprazole alone, the effects of the resulting hypergastrinemia on the enterochromaffinlike cells was reflected in increased histidine decarboxylase activity, increased histamine concentration, and increased number of enterochromaffinlike cells. The general trophic effects on the stomach were seen as increased stomach and oxyntic mucosal weight and increased mucosal thickness. Treatment with alpha-fluoromethylhistidine plus omeprazole markedly reduced the histidine decarboxylase activity and histamine concentration, but the weight of the stomach and oxyntic mucosa, the enterochromaffinlike cell density, and intensity of histidine decarboxylase immunostaining were increased to at least the same extent as after omeprazole alone. These observations indicate that enterochromaffinlike cell histamine is not important for a full expression of gastrin-evoked trophic effects in the stomach.
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| 6. |
- Duan, Rui-Dong, et al.
(författare)
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Gastric inhibitory polypeptide stimulates synthesis of pancreatic lipase and colipase in rat.
- 1992
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Ingår i: American Journal of Physiology: Gastrointestinal and Liver Physiology. - 1522-1547. ; 262:5 Pt 1, s. 779-784
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Tidskriftsartikel (refereegranskat)abstract
- Effects of short-term infusion and long-term injection of gastric inhibitory polypeptide (GIP) on changes in pancreatic lipase and colipase contents in rats were studied, and mRNAs encoding for lipase and colipase were determined by Northern blot hybridization with specific cDNA probes. GIP infused at a dose of 3 micrograms/h for 24 h significantly increased the pancreatic lipase content by 34% (P less than 0.05) but had no significant effect on colipase and amylase contents. No change in mRNAs encoding for these proteins was found after infusion of GIP for 24 h. Injection of GIP (5-60 micrograms/kg) three times a day for 5 days dose dependently increased the contents of lipase and colipase, with the increase in colipase being more prominent. Injection of GIP for 5 days at a dose of 30 micrograms.kg-1.day-1 increased colipase and lipase contents by 52 and 25%, and their corresponding mRNAs by 60 and 160%, respectively. The amylase mRNA was not changed by injection of GIP. It is concluded that GIP has a specific stimulatory effect on the synthesis of pancreatic lipase and colipase at both pretranslational and translational levels.
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| 7. |
- Mathiesen, U L, et al.
(författare)
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Anti-hepatitis C virus screening will reduce the incidence of post-transfusion hepatitis C also in low-risk areas
- 1992
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 1502-7708 .- 0036-5521. ; 27:6, s. 443-448
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Tidskriftsartikel (refereegranskat)abstract
- The incidence of post-transfusion hepatitis non-A, non-B (PTH-NANB) was prospectively assessed in two areas in the southeast region of Sweden. Patients undergoing hip arthroplasty were studied with blood sampling for alanine aminotransferase analysis before and at 2, 3, and 4 months after transfusion. Of the patients 97% and 82% were transfused and received a mean of 5.5 and 3.4 units in Linkoping and Oskarshamn, respectively. None of 38 patients in Oskarshamn but 4 of 144 patients (2.8%) in Linkoping contracted PTH-NANB. Two of these four patients developed antibodies against hepatitis C virus (HCV) by the first-generation anti-HCV enzyme-linked immunosorbent assay (ELISA) (C100). The other two patients remained negative by this test. HCV infection was, however, indicated in all four patients by positive second-generation anti-HCV ELISA confirmed by positive second-generation recombinant immunoblot assay (4-RIBA). Three of the patients were positive by polymerase chain reaction (PCR). Serum from one blood donor to the four hepatitis patients (altogether three donors) was found positive by first- and second-generation anti-HCV ELISA and 4-RIBA and was also PCR-positive. Three other blood donors, who did not transmit hepatitis, were anti-HCV ELISA (C100)-positive. This study shows that if anti-HCV ELISA had been available at the start of the trial, all cases of PTH would have been avoided at the expense of only 0.7% transfusion units discarded. Routine anti-HCV ELISA testing of all transfusion units will reduce the incidence of PTH-C even in low-risk areas.
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| 8. |
- Raab, Y, et al.
(författare)
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A technique for segmental rectal and colonic perfusion in humans.
- 1992
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Ingår i: American Journal of Gastroenterology. - 0002-9270 .- 1572-0241. ; 87:10, s. 1453-9
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Tidskriftsartikel (refereegranskat)abstract
- To enable a better characterization of pathophysiologic processes in colon and rectum, we have developed a perfusion technique for collection of soluble substances and cells from standardized intestinal segments. A tube with balloons attached to its outer wall was endoscopically introduced into the rectum and sigmoid colon, and its position ascertained fluoroscopically. The balloons delimited two segments, one in the sigmoid colon and one in the rectum. The segments were simultaneously perfused by a buffer at 37 degrees C. After a 30-min rinsing period, perfusate and cells were collected at 20-min intervals. Of 51 attempted perfusions, 45 were successfully completed. Recovered volumes equaled those infused. Leakage from the proximal intestine to the segments was negligible. In 18 healthy volunteers, the mean perfusate concentration from the rectal segment was 57.5 (27.5-120.2) mg/L for albumin, 1.3 (1.0-1.7) micrograms/L for eosinophil cationic protein, 5.1 (2.8-9.5) ng/L for prostaglandin E2, and 61.7 (41.7-89.1) micrograms/L for hyaluronan, and all values were lower in the sigmoid segment. Steady state conditions were achieved from the second perfusion period. The perfusate contained 4-80 x 10(4) cells, more than 95% of which were epithelial cells. The technique is safe, has a good subject compliance, and seems to be a valuable tool in investigations on quantitative release of soluble substances and cells in, e.g., colorectal inflammation.
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