AbstractBackground: The direct contribution of bile to gastric inhibitory polypeptide (GIP) release and the role of bile in regulating GIP secretion in response to fat ingestion are still obscure. The present study was aimed to clarify the influence of bile on GIP release. Methods: Seven patients with obstruction of the common bile duct and nine volunteers participated in the study. Fifty milliliters of Lipomul® was ingested, and GIP was measured serially for 180 min. After intraduodenal instillation of pooled autologous bile for 2 days, the same study was carried out. Results: The fat-stimulated GIP response was significantly lower in the patients than in the controls. The basal GIP level did not change on bile instillation, but the GIP response to fat ingestion was significantly increased on bile instillation compared with that in the absence of bile. Conclusions: Intraluminal bile alone does not stimulate the secretion of GIP, but it promotes GIP secretion in response to fat ingestion.Key Words: Bilebile duct obstructiongastric inhibitory polypeptideperiampullary tumor
Proteins on the membrane of secretory granules (SGs) involved in their biogenesis and exocytosis are poorly characterized compared with those of synaptic vesicle in neurons. Thus the secretory granule membrane was prepared from a mouse pancreatic β-cell line MIN6 by subcellular fractionation, and protein constituents were analyzed by microscale two-dimensional liquid chromatography coupled with electrospray ionization tandem mass spectrometry. Using this proteomics approach, one of the p24 family proteins, p23, was unexpectedly found in the granule fraction, although p24 proteins are generally regarded as functioning in the early secretory pathways between the endoplasmic reticulum and the Golgi apparatus. We further showed that p23 is expressed at high levels in endocrine cells. Furthermore, immunocytochemical analyses of pancreatic β-cells at the light and electron microscopic levels demonstrated that a significant amount of p23 is localized on the insulin granule membrane, although it is most intensely concentrated at the cis-Golgi compartment as previously shown in non-endocrine cells. These findings suggest that a fraction of p23 enters post-Golgi compartments and may function in the biogenesis and/or quality control of SGs.
Although it is well established that Ras requires membrane localization for activation of its target molecule, Raf-1, the reason for this requirement is not fully understood. In this study, we found that modified Ras, which is purified from Sf9 cells, could activate Raf-1 in a cell-free system, when incorporated into liposome. Using a bifunctional cross-linker and a protein-fragmentation complementation assay, we detected dimer formation of Ras in the liposome and in the intact cells, respectively. These results suggest that dimerization of Ras in the lipid membrane is essential for activation of Raf-1. To support this, we found that, when fused to glutathione S-transferase (GST), unprocessed Ras expressed in Escherichia coli could bypass the requirement for liposome. A Ras-dependent Raf-1 activator, which we previously reported (Mizutani, S., Koide, H., and Kaziro, Y. (1998)Oncogene 16, 2781–2786), was still required for Raf-1 activation by GST-Ras. Furthermore, an enforced dimerization of unmodified oncogenic Ras mutant in human embryonic kidney (HEK) 293 cells, using a portion of gyrase B or estrogen receptor, also resulted in activation of Raf-1. From these results, we conclude that membrane localization allows Ras to form a dimer, which is essential, although not sufficient, for Raf-1 activation.
Parathyroid hormone–related protein (PTHrP) increases the content and mRNA level of insulin in a mouse β-cell line, MIN6, and primary-cultured mouse islets. We examined the mechanism of PTHrP-induced insulin expression. The PTHrP effect was markedly augmented by SB203580, a mitogen-activated protein (MAP) kinase inhibitor, and SB203580 itself increased insulin expression extensively, even without PTHrP. Because SB203580 inhibits both p38 and c-jun NH2-terminal kinases (JNKs), we investigated the JNK-specific inhibitor SP600125. SP600125 also increased insulin content and its mRNA level. PTHrP induced dephosphorylation of JNK1/2, and PTHrP-induced insulin expression was blocked by a dominant-negative type JNK-APF. We suspected that dual specificity MAP kinase phosphatases (MKPs) may be involved in the PTHrP-induced insulin expression by inactivating JNK1/2. MIN6 cells contained at least five MKPs, among which only MKP-1 was inducible by PTHrP. PTHrP-induced insulin expression was blocked by the MKP-1 expression inhibitor Ro-31-8220, indicating that the PTHrP effect is mediated by MKP-1. Indeed, adenoviral MKP-1 expression increased insulin expression by decreasing a phosphorylation form of JNKs and a resulting phosphorylated form of c-jun in MIN6 cells. The phosphorylated form of c-jun is known to repress cAMP-dependent insulin gene promoter activity. Thus, MKP-1 controls the insulin expression by downregulating a JNK/c-jun pathway.
We experienced a case of intussusception associated with Schonlein-Henoch purpura. A one-year-old boy who had been admitted with complaints of abdominal pain and tarry stool was diagnosed as Schonlein-Henoch purpura. During medical treatment he had a sudden ileus and was diagnosed as intussusception by a barium enema study. Operation revealed an ilio-colic type intussusception. The postoperative couse was uneventful by giving blood coagulation factor XIII. Recently there were some reports of a specific decrease of coagnulation factor XIII in children with Schonlein-Henoch purpura, and this case also showed a remarkable decrease. Thus it was suggested that the blood coagulation factor XIII regimen was effective for surgical complication of Schonlein-Henoch purpura.
We conducted combined therapy of weekly paclitaxel and doxifluridine (5'-DFUR) for 23 cases of advanced and recurrent gastric carcinomas to investigate their efficacy and safety. Subjects included 7 unresectable cases, 5 noncurative resection cases, and 11 recurrent cases. Twenty of the 23 subjects had a history of prior treatment with another anticancer drug. The treatment regime consisted of one course comprising 70 mg/m(2)of paclitaxel weekly for three consecutive weeks followed by one week rest, combined with 800 mg/day of 5'-DFUR orally. Results revealed a response rate of 17.6% (3/17), with 2 cases of CR, 1 case of PR, 10 cases of NC, and 4 cases of PD. One of the CR cases was an unresectable case involving a primary tumor, liver metastasis, and abdominal lymph node metastasis, while the other was a recurrent case involving abdominal lymph node metastasis. The median survival period was 387 days. The one-and two-year survival rates were 52% and 24%, respectively. In terms of adverse effects, there were only single cases of grade 3 leukopenia and grade 3 neutropenia, with no cases of grade 4 hemotoxicity. Both patients could be treated as outpatients. Combination therapy of weekly paclitaxel and 5'-DFUR can be an effective and safe therapy for advanced and recurrent gastric carcinomas.
A 61-year-old woman, who had undergone total right pneumonectomy 22 months before due to lung cancer (adenosquamous cell carcinoma) was admitted for macroscopic hematuria. Abdominal CT showed two renal tumors in the right kidney. Right radical nephrectomy was performed, because no imaging study showed any other metastasis. Pathological examination revealed adenosquamous cell carcinoma, which was the same pathology as the lung cancer had been. She died of the left lung metastasis 24 months after right radical nephrectomy. Her prognosis was thought to have been prolonged by the operation of right radical nephrectomy.
