[Disorders of iron metabolism involving erythropoiesis: molecular mechanism of gut-liver-bone marrow axis].
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Adult↗
Biomedical subjects
Y Kohgo
Publications and source records attributed to Y Kohgo.
Activation of peroxisome proliferator-activated receptor gamma by troglitazone inhibits cell growth through the increase of p27KiP1 in human. Pancreatic carcinoma cells.
In the present study, we examine whether human pancreatic carcinoma cells express peroxisome proliferator-activated receptor gamma (PPARgamma) and the effect of PPARgamma activation by its selective ligand on cellular growth in pancreatic cancer cells. Immunohistochemical study of resected human pancreata using a polyclonal PPARgamma antibody revealed that PPARgamma protein expression in the nuclei of carcinoma cells was observed in 9 of 10 pancreatic adenocarcinomas. In contrast, normal pancreatic duct epithelial cells in the samples expressed no PPARgamma. Reverse transcription-PCR and Northern blot analysis demonstrated that all four tested human pancreatic cancer cell lines, PK-1, PK-8, PK-9, and MIA Paca-2, expressed PPARgamma mRNA. Luciferase assay in PK-1 cells showed that troglitazone, a selective ligand for PPARgamma, transactivated the transcription of a peroxisome proliferator response element-driven promoter in a dose-dependent fashion. Troglitazone inhibited the growth of all four pancreatic carcinoma cell lines in a dose-dependent manner. Cell cycle analysis by flow cytometry demonstrated that troglitazone induced G1 arrest in PK-1 cells. To examine the role of cyclin-dependent kinase inhibitors in the G1 arrest by troglitazone, we determined p27KiP1, p21CiP1/Waf1, or p18Ink4c protein expression by Western blot analysis in troglitazone-treated PK-1 cells. Troglitazone increased p27Kip1 but not p21Cip1/Waf1 or p18Inkc protein levels in time- and dose-dependent manners. To clarify the functional importance of p27Kip1 in the cell growth inhibition by troglitazone. All these results suggest that PPARgamma could be considered as a possible target molecule for treatment in human pancreatic carcinomas.
Adenocarcinoma↗
Overexpression of hemochromatosis protein, HFE, alters transferrin recycling process in human hepatoma cells.
HFE is a MHC class 1-like protein that is mutated in hereditary hemochromatosis. In order to elucidate the role of HFE protein on cellular iron metabolism, functional studies were carried out in human hepatoma cells (HLF) overexpressing a fusion gene of HFE and green fluorescent protein (GFP). The expression of HFE-GFP was found to be localized on cell membrane and perinuclear compartment by fluorescent microscopy. By co-immunoprecipitation and Western blotting, HFE-GFP protein formed a complex with endogenous transferrin receptor and beta(2)-microglobulin, suggesting that this fusion protein has the function of HFE reported previously. We then examined the (59)Fe uptake and release, and internalization and recycling of (125)I-labeled transferrin in order to elucidate the functional roles of HFE in the cell system. In the transfectants, HFE protein decreased the rate of transferrin receptor-dependent iron ((59)Fe) uptake by the cells, but did not change the rate of iron release, indicating that HFE protein decreased the rate of iron influx. Scatchard analysis of transferrin binding to HFE-transfected cells showed an elevation of the dissociation constant from 1.9 to 4. 3 nM transferrin, indicating that HFE protein decreased the affinity of transferrin receptor for transferrin, while the number of transferrin receptors decreased from 1.5x10(5)/cell to 1. 2x10(5)/cell. In addition, the rate of transferrin recycling, especially return from endosome to surface, was decreased in the HFE-transfected cells by pulse-chase study with (125)I-labeled transferrin. Our results strongly suggest an additional role of HFE on transferrin receptor recycling in addition to the decrease of receptor affinity, resulting in the reduced cellular iron.
Carcinoma, Hepatocellular↗
Inhibition of food intake by central injection of anti-orexin antibody in fasted rats.
It has been shown that intracerebroventricular injection of synthetic orexins stimulated food intake in rats. This pharmacological evidence suggests that orexins may have a role for the central regulation of feeding. In the present study, we investigated the hypothesis of whether endogenous orexins indeed play a vital role in feeding behavior. An anti-orexin polyclonal antibody was used throughout the study. First, we examined the specificity of the antibody to orexin by Western blot analysis and immunohistochemistry. Next, the effects of central injection of the orexin antibody on food intake in 24-h-fasted rats were evaluated. Western blot analysis revealed that the orexin antibody detected synthetic orexin-A. Immunohistochemical study showed that orexin-positive neurons were identified only in the lateral hypothalamic area, in agreement with previous reports. Neither control antibody nor the orexin antibody preabsorbed with excess amount of orexin-A detected neurons, indicating that the orexin antibody is specific. Intracisternal but not intraperitoneal injection of the orexin antibody dose-dependently suppressed feeding. All these results suggest that immunoneutralization of endogenous orexins in the brain reduced food intake. In other words, we suggest that endogenous brain orexin may have a physiologically relevant action on feeding behavior.
Animals↗
Morphogenesis of nonpolypoid colorectal adenomas and early carcinomas assessed by cell proliferation and apoptosis.
Nonpolypoid neoplasms, as well as ordinary polypoid tumours, are occasionally found in the colorectum. To clarify whether cell kinetic status affects the macroscopic morphology of colorectal neoplasms, we investigated proliferative indices (PI), apoptotic indices (AI), and the expression of apoptosis-related gene products. We examined 110 colorectal neoplasms comprised of 36 polypoid, 38 flat elevated and 36 depressed tumours. According to WHO's criteria these tumours consisted of 61 adenomas with low grade dysplasia (LGD), 30 adenomas with high grade dysplasia (HGD) and 19 carcinomas with submucosal invasion. Apoptotic cells were detected by TUNEL staining. Proliferating cells and apoptosis-related gene products were assessed by immunohistochemistry for Ki-67, p53, Bcl-2, and Bax antigens. AI were closely associated with macroscopic morphology in adenomas but not in carcinomas. PI were relatively constant among the three macroscopic types in adenomas and carcinomas. Median AI values of polypoid, flat elevated and depressed tumours were 1.8%, 2.1% and 4.6% for adenomas with LGD, 0.8%, 2.4% and 6.2% for adenomas with HGD and 2.9%, 4.0% and 3.6% for carcinomas, respectively. Overall PI were significantly higher in carcinomas than in adenomas with LGD, whereas AI were not different. Although the incidence of expression was significantly higher in carcinomas for p53 and in adenomas for Bcl-2 than the others, the expression of apoptosis-related gene products (p53, Bcl-2 and Bax) was similar among polypoid, flat elevated and depressed tumours. Macroscopic morphology of colorectal adenomas is determined by the apoptosis not by proliferation, and high apoptosis found in depressed adenomas implies their low net growth.
Adenoma↗
Immunochemical characterization of monoclonal protein in the serum of a patient with Waldenstr]om's macroglobulinemia showing both pyroglobulin and cryoglobulin properties.
A patient with Waldenstr]om's macroglobulinemia whose serum demonstrated properties of both pyroglobulin and cryoglobulin was studied. A monoclonal (M) protein in the serum of the patient was identified by immunoelectrophoresis (IEP) and immunofixation electrophoresis (IFE) as IgM-lambda. The M-protein was separated by gel permeation high-performance liquid chromatography (HPLC). Cryoglobulin in the serum was isolated by the method of cold precipitation. The cryoglobulin was identified as IgM-lambda type by IEP and was the same M-protein as that which occurred in this patient's serum. The purified cryoglobulin also had the properties of a pyroglobulin. Neither property disappeared following pretreatment with 2-mercaptoethanol (2-ME), urea, and Triton X-100 detergent, and deglycosylation with N-glycanase (E.C. 3.5.1.52). We suggest that these abnormal properties were caused by the molecular abnormality of the IgM-lambda M-protein.
Aged↗
Expression of glucocorticoid receptor beta in lymphocytes of patients with glucocorticoid-resistant ulcerative colitis.
BACKGROUND & AIMS: Recently, the glucocorticoid receptor beta (hGRbeta) was suggested to play a role as a dominant negative regulator for determining glucocorticoid response. The aim of this study was to clarify whether reverse-transcription polymerase chain reaction (RT-PCR) analysis of hGRbeta messenger RNA (mRNA) can predict the response to glucocorticoids in patients with ulcerative colitis. METHODS: Total RNA obtained from peripheral blood mononuclear cells (PBMCs) of 23 patients with ulcerative colitis and 20 healthy volunteers was reverse transcribed; the resulting complementary DNA was amplified using specific primers for hGRalpha and hGRbeta. Protein expression of hGR in PBMCs was confirmed by immunoprecipitation-Western blot analysis. RESULTS: The expression of hGRalpha mRNA (477 base pairs) was detected in all patients and all healthy volunteers. In contrast, a hGRbeta mRNA (366 base pairs) was detected in 1 (9.1%) of 11 glucocorticoid-sensitive patients, 10 (83.3%) of 12 glucocorticoid-resistant patients, and 2 (10%) of 20 healthy volunteers. The positive rate of hGRbeta mRNA in the resistant group was significantly higher than that in the sensitive group (P = 0.0019). The hGRbeta band could be detected by immunoprecipitation-Western blotting in hGRbeta mRNA-positive patients. CONCLUSIONS: The results show that the expression of hGRbeta mRNA in PBMCs examined by RT-PCR may serve as a novel predictor of glucocorticoid response in ulcerative colitis.
Adolescent↗
Pancreatic duct obstruction caused by malignant islet cell tumors of the pancreas.
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Adenoma, Islet Cell↗
Increased serum leptin by cholecystitis in a diabetic patient.
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Acute Disease↗
Characterization of prostanoid receptors mediating contraction of the gastric fundus and ileum: studies using mice deficient in prostanoid receptors.
Receptors mediating prostanoid-induced contractions of longitudinal sections of gastric fundus and ileum were characterized by using tissues obtained from mice deficient in each type and subtype of prostanoid receptors. The fundus and ileum from mice deficient in either EP(3) (EP(3)(-/-) mice), EP(1) (EP(1)(-/-) mice) and FP (FP(-/-) mice) all showed decreased contraction to PGE(2) compared to the tissues from wild-type mice, whereas contraction of the fundus slightly increased in EP(4)(-/-) mice. 17-phenyl-PGE(2) also showed decreased contraction of the fundus from EP(3)(-/-), EP(1)(-/-) and FP(-/-) mice. Sulprostone showed decreased contraction of the fundus from EP(3)(-/-) and FP(-/-) mice, and decreased contraction of the ileum to this compound was seen in tissues from EP(3)(-/-), EP(1)(-/-) and FP(-/-) mice. In DP(-/-) mice, sulprostone showed increased contraction. DI-004 and AE-248 caused the small but concentration-dependent contraction of both tissues, and these contractions were abolished in tissues obtained from EP(1)(-/-) and EP(3)(-/-) mice, respectively, but not affected in other mice. Contractions of both fundus and ileum to PGF(2)alpha was absent at lower concentrations (10(-9) to 10(-7) M), and suppressed at higher concentrations (10(-6) to 10(-5) M) of the agonist in the FP(-/-) mice. Suppression of the contractions at the higher PGF(2)alpha concentrations was also seen in the fundus from EP(3)(-/-), EP(1)(-/-) and TP(-/-) mice and in the ileum from EP(3)(-/-) and TP(-/-) mice. Contraction of the fundus to PGD(2) was significantly enhanced in DP(-/-) mice, and contractions of the fundus and ileum to this PG decreased in FP(-/-) and EP(3)(-/-) mice. Contractions of both tissues to I-BOP was absent at 10(-9) to 10(-7) M and much suppressed at higher concentrations in TP(-/-) mice. Slight suppression to this agonist was also observed in the tissues from EP(3)(-/-) mice. PGI(2) induced small relaxation of both tissues from wild-type mice. These relaxation reactions were much potentiated in EP(3)(-/-) mice. On the other hand, significant contraction to PGI(2) was observed in both tissues obtained from IP(-/-) mice. These results show that contractions of the fundus and ileum induced by each prostanoid agonist are mediated by actions of this agonist on multiple types of prostanoid receptors and in some cases modified by its action on relaxant receptors.
Acetylcholine↗
Fas-mediated apoptosis of peripheral blood mononuclear cells in patients with hepatitis C.
In the present study, we demonstrated that a close relationship exists between hepatitis C virus (HCV) infection of peripheral blood mononuclear cells (PBMCs) and cell-surface Fas expression in patients with hepatitis C, and showed the possibility of PBMCs apoptosis via a Fas-mediated system. The expression of Fas on PBMCs was found by flowcytometric analysis to be significantly increased in these patients. In addition, the treatment of patients' PBMCs with anti-Fas antibody induced cell death, with nuclear condensation and fragmentation and cellular DNA fragmentation. These data indicate that the patients' PBMCs expressed a large amount of functional Fas on the cell surface and were susceptible to stimulation against Fas, causing apoptotic cell death. We then quantified the serum-soluble Fas ligand (sFasL), which was known to bind to Fas and induce the apoptotic signals into the sensitized cells. The patients' serum sFasL levels were significantly higher than those of normal subjects and showed a good negative correlation with their PBMC number. To demonstrate the correlation between Fas expression and HCV infection, nested reverse transcriptase polymerase chain reaction (RT-PCR) was performed to detect HCV RNA. Interestingly, HCV RNA was preferentially detected from Fas-positive cells but not from Fas-negative cells, which had been isolated from PBMCs by magnetic beads. These results suggest that HCV infection of PBMCs might induce Fas expression and additional stimulation such as sFasL might induce apoptosis in these Fas-expressing cells. These mechanisms, in addition to hypersplenism, may explain the decrease in the number of PBMCs observed in patients with chronic hepatitis C.
Adult↗
Temporary use of an accuflex stent for unextractable common bile duct stones.
Endoscopic management has become the main therapeutic approach for the extraction of common bile duct (CBD) stones, and successful removal can be achieved in 80-90% patients using conventional balloon and basket techniques. However, if it is difficult to completely fragment a stone, or to clear the CBD, which may occur for a variety of reasons, the therapeutic problem will remain. When bile duct stones can not be removed, a viable management option is to place a biliary stent to ensure drainage. However, recent studies of long-term biliary stenting, with a plastic stent, showed a relatively high rate of morbidity and mortality. We report an alternative, unique treatment for unextractable common bile duct stones, using the temporal placement of an expandable metallic stent (EMS) to facilitate passage of fragments through the papilla.
Aged↗
Colonoscopic diagnosis of asymptomatic acute appendicitis.
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Acute Disease↗
Autoantibodies against the specific epitope of human tropomyosin(s) detected by a peptide based enzyme immunoassay in sera of patients with ulcerative colitis show antibody dependent cell mediated cytotoxicity against HLA-DPw9 transfected L cells.
BACKGROUND AND AIMS: Recent studies suggest that tropomyosin (TM) may act as a putative autoantigen in ulcerative colitis (UC). Recently, we identified, by computer homology analysis, a specific peptide (HIAEDADRK) in human TM that can bind to HLA-DPw9. The aim of this study was to investigate the presence of autoantibodies against this peptide in UC. METHODS: Antibodies were measured by ELISA with a synthetic peptide in 20 healthy volunteers, 48 patients with UC, 26 with Crohn's disease (CD), eight with primary sclerosing cholangitis (PSC), and six with primary biliary cirrhosis (PBC). The functional significance of antibodies was investigated by antibody dependent cell mediated cytotoxicity (ADCC) against DPw9 transfected L cells using a standard (51)Cr release assay. RESULTS: Optical density values (mean (SD)) of sera from patients with UC (1.40 (0. 52)) and PSC (1.65 (0.12)) were significantly higher than those from healthy volunteers (0.32 (0.28)) (p<0.05), CD (0.50 (0.34)) (p<0.05) and PBC (0.14 (0.09)) (p<0.05). Values in UC decreased with clinical improvement. The ADCC activity of UC sera correlated well with antibody titre against this synthetic peptide. CONCLUSIONS: Anti-TM antibody was detected in UC sera by a specific peptide based ELISA with high reproducibility. This peptide may be an antigenic epitope of TM involved in the immunopathogenesis of UC and, perhaps, PSC.
Adolescent↗
Balloon-occluded endoscopic retrograde ileography.
For diagnostic ileography, the authors developed balloon-occluded endoscopic retrograde ileography and performed 77 studies in 36 consecutive patients with Crohn disease. Balloon-occluded endoscopic retrograde ileography proved to be useful in visualization of minute mucosal lesions such as aphthous ulcers and lymphoid hyperplasia in the distal ileum, and satisfactory ileographic images of Crohn disease were obtained in 54 (70%) studies.
Adolescent↗
Cocaine-amphetamine-regulated transcript (CART) acts in the central nervous system to inhibit gastric acid secretion via brain corticotropin-releasing factor system.
Recent study has indicated that cocaine-amphetamine-regulated transcript (CART) is an anorectic chemical in the brain. In the present study, we examined the hypothesis that CART may act in the central nervous system to alter gastric function. Food consumption, gastric acid secretion, and gastric emptying were measured after injection of CART into the cerebrospinal fluid in 24-h fasted Sprague Dawley rats. Central injection of CART inhibited food intake, gastric acid secretion, and gastric emptying. In contrast, ip injection of CART failed to inhibit gastric acid secretion and gastric emptying, suggesting that CART acts in the brain to suppress gastric acid secretion and gastric emptying. In the vagotomized animals, centrally administered CART did inhibit pentagastrin-stimulated gastric acid secretion. The CART-induced acid inhibition was also observed in rats treated with indomethacin, a cyclooxygenase inhibitor. In contrast, pretreatment with central administration of a CRF receptor antagonist, alpha-helical CRF9-41, completely blocked the central CART-induced inhibition of gastric acid secretion. All these results suggest that CART acts in the brain to inhibit gastric function via brain CRF system. The vagal pathway and the prostaglandin system are not involved in the acid inhibition.
Animals↗
Recent advances in therapy for patients with inflammatory bowel disease.
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Glucocorticoids↗