Inhibition of CN (protein phosphatase-2B) suppresses Ca2+-mediated acid secretion in rats.

BACKGROUND AND AIM: It has been suggested that CN (calcineurin, protein phosphatase-2B) regulates signal transduction, particularly in various secretory cells. In this study, we examined whether CN plays a role in stimulus-secretion coupling of gastric parietal cells. MATERIALS AND METHODS: Localization of CN in gastric epithelial cells was examined immunohistochemically. The role of CN in the acid secretion pathway of gastric parietal cells was assessed by evaluating the effect of FK506, a specific inhibitor of CN, on gastric acid secretion in pylorus-ligated rats. In addition, the effect of FK506 on secretagogue (carbachol, tetragastrin and histamine)-stimulated acid secretion was investigated in lumen-perfused rats. RESULTS: CN was specifically expressed in gastric parietal cells and chief cells of the gastric mucosal epithelium immunohistochemically. FK506 dose-dependently inhibited gastric acid secretion in pylorus-ligated rats. In lumen-perfused rats, FK506 completely inhibited acid secretion prestimulated by carbachol and tetragastrin, agonists known to increase cytosolic Ca2+, but did not affect acid secretion prestimulated by histamine. CONCLUSIONS: Our findings demonstrate that FK506 has a potent antisecretory effect in parietal cells through inhibition of only Ca2+-mediated acid secretion pathways. As FK506 is known to specifically inhibit CN, which plays an important role in signal transduction in various secretory cells, protein dephosphorylation signalling might also be crucial for gastrin and M3 muscarine receptor-mediated stimulation of proton pump.

Specific preinduction of 60-kDa heat shock protein (chaperonin homolog) by TRH does not protect colonic mucosa against acetic acid-induced lesion in rats.

In order to study the cytoprotective function of colonic heat shock proteins (HSPs) in vivo, the effect of specific preinduction of HSP60 by thyrotropin-releasing hormone (TRH) administration on the development of acetic acid-induced colonic mucosal lesion was investigated. Expression of 60-kDa, 72-kDa, and 90-kDa heat shock proteins (HSP60, HSP72, and HSP90, respectively) in rat colonic mucosa was investigated by western blot and immunohistochemical analyses before and after TRH administration. Following pretreatment with or without TRH administration, the rats received intrarectal infusion of 5% acetic acid. The colonic mucosal damage was macroscopically evaluated 24 hr after the intrarectal infusion of acetic acid. Expression of HSP60 was significantly increased by TRH administration in the colonic mucosa, whereas HSP72 and HSP90 did not increase. Immunohistochemical study also showed a significant increase in HSP60 in colonic mucosal cells, especially at the surface of the colonic mucosa after TRH administration. No histopathologic alteration was observed in the colonic mucosa after TRH administration. The colonic mucosal damage caused by intrarectal infusion of 5% acetic acid was not prevented by preinduction of HSP60. We demonstrated that specific preinduction of HSP60 by TRH administration did not show cytoprotective function in the colonic mucosa, although this protein plays a crucial role for cytoprotection in the pancreatic acinar cells. Our results indicate that the role of HSP60 may be different in each organ with respect to cytoprotection.

Massive accumulation of M and H subunits of neurofilament proteins in spinal motor neurons of neurofilament deficient Japanese quail, Quv.

Quiver (Quv) is a non-sense mutation of neurofilament protein L subunit (NF-L) that causes neurofilament deficiency with preserved microtubules in Japanese quail. Anti-NF-M and anti-NF-H mAbs stained cell bodies of motor neurons in Quv embryo spinal cords much more intense than those in control spinal cords. Volume of motor neurons in Quv spinal cords increased to 2.3 times of control motor neurons. Immunoblot of Quv spinal cords revealed a relative increase in non- and hypo-phosphorylated NF-M and NF-H, and a decrease in the total amount of NFs. Quv sciatic nerves showed faintly reacted phosphorylated NF-M and NF-H. These results suggest that deficiency of assembled neurofilament results in decreased axonal transport of NFs and accumulation of NFs in cell bodies of spinal motor neurons.

Analysis of biochemical and virological efficacy of human lymphoblastoid interferon (IFN) in patients with compensated type C liver cirrhosis: comparative study between increase in individual IFN dose and prolonging of treatment period, using a multicenter randomized controlled trial.

A controlled trial was conducted to compare the efficacy of interferon (IFN) between two groups of patients with type C liver. Thirty-five patients were randomly assigned to group A (17 patients) or group B (18 patients). The former received 3 megaunits (MU) of human lymphoblastoid IFN six days per week for two weeks, followed by three days per week for 50 weeks; the latter group received 6 MU six days per week for two weeks followed by three days per week for 24 weeks. The percentages of biological sustained responders (B-SR) and virological sustained responders (V-SR) were 29.4 and 23.5%, respectively, in group B, and 17.6% for both in group A. The therapeutic effects were not different between two groups. HCV genotype 2 accounted for significantly higher percentage of B-SR and V-SR (both 57.1%, respectively). These findings indicate that IFN is effective in type C cirrhosis with genotype 2.

Iatrogenic GB virus C/hepatitis G virus infection in an area endemic for hepatitis C virus.

GB virus C/hepatitis G virus (GBV-C/HGV) is reported to be transmitted by blood products. This study reports infection with GBV-C/HGV from Area-O of town T, an area of high prevalence of antibody to hepatitis C virus (anti-HCV). Four hundred and thirty-five inhabitants of Area-O in town T were examined. Three hundred and forty-three inhabitants of Area-H in town T (where differences of age or sex are not markedly different to Area-O) were studied as controls. We investigated the virus markers and conducted a survey of life history in both areas. The seroprevalence of anti-HCV and GBV-C/HGV markers in Area-O was 17.7% and 11.7%, significantly higher than in Area-H (1.5% and 4.4%). The prevalence of GBV-C/HGV markers was significantly higher in the anti-HCV-positive group than in the sero-negative group. Anti-HCV- or GBV-C/HGV positive subjects tended to have a history of intravenous medications at hospital C in town T, suggesting iatrogenic infection through insufficient sterilization of needles and/or syringes.

Pontine atrophy in spinocerebellar ataxia type 6.

To investigate the clinical range of spinocerebellar ataxia type 6 (SCA6), we screened CAG repeat expansion in the voltage-dependent alpha 1A calcium channel gene (CACNL1A4) in 71 ataxic patients in 60 families; 54 patients in 43 families with hereditary ataxia and 17 sporadic patients. Thirteen patients with SCA6 were detected to have elongated CAG in CACNL1A4. Of these, 7 patients had been diagnosed as having hereditary cerebellar cortical atrophy, and 6 patients had been found to have sporadic occurrence. One patient showed distinct pontine atrophy with prominent horizontal or oblique gaze nystagmus which is an unusual feature in sporadic olivopontocerebellar atrophy. For the efficient screening of SCA6, we would propose testing CAG repeat expansion in CACNL1A4, in patients with one of two markers: (1) horizontal or oblique gaze nystagmus without other eye movement disorders, (2) pure cerebellar atrophy, even if occurrence is sporadic. We should note that the pontine atrophy could also be caused by CAG repeat expansion in CACNL1A4.

Corticosteroid pretreatment prevents small intestinal mucosal lesion induced by acetic acid-perfusion model in rats.

One of the important problems in experimentally induced small intestinal lesions is that there is no reproducible model of diffuse and stable mucosal lesion. In this paper, we studied in detail the effects of continuous perfusion of various concentrations of acetic acid on the rat small intestinal mucosa. In order to evaluate its applicability for screening of the preventive effect of drugs on gut damage, we also evaluated the efficacy of corticosteroid pretreatment in preventing acetic acid-induced mucosal lesion. Male Sprague-Dawley rats were fasted for 12 hr, and the small intestinal lumen was perfused with 1%, 1.5%, 2.5%, 3%, 3.75% (pH 2.4-2.6) acetic acid or saline (control) at 1 ml/min for 15 min. In separate experiments, the effect of preadministration of budesonide (0.5 or 0.75 mg/kg/day) and prednisone (0.75 mg/kg/day) on 1.5% acetic acid-induced mucosal damage was investigated. Macroscopic and microscopic lesions occurred diffusely in a concentration-dependent fashion. Histological findings revealed signs of transmural inflammation characterized by mucosal-submucosal edema, ulceration, and neutrophil infiltration. Mucosal-submucosal height had an inverse relation with the acetic acid concentrations perfused. Myeloperoxidase activity levels increased several-fold in the acetic acid-perfused groups. Corticosteroid pretreatment prevented microscopic damage and was associated with reduction of MPO activity levels in 1.5% acetic acid-perfused rats. We conclude that this simple and reproducible model could be applied for the screening of new drugs in the gastrointestinal tract in which large numbers of animals are taken into account.

[Hereditary ataxias in Akita prefecture].

To provide a genetic survey of hereditary ataxia, we performed PCR screening of SCA1, SCA2, MJD1 (SCA 3), SCA6, DRPLA, with 71 patients in 61 families living in Akita prefecture (1,205,571 population in 1997) in Japan. Of 71 patients in 61 families, 18 MJD1, 14 SCA6, 5 DRPLA, 1 SCA1 and 1 SCA2 patients were detected. Eighty percent of autosomal dominant inherited spinocerebellar degeneration (AD-SCD) including 7 spoladic patients genetically diagnosed as AD-SCD was MJD1 (45.7%) and SCA6 (34.3%). These suggest the prevalence rate of hereditary ataxias in Akita prefecture; 1.5 and 1.2/100,000 of MJD1 and SCA6, respectively. Only one patient of SCA1 was detected, which was frequently reported in Hokkaido and Tohoku area in Japan.

Association of 72-kDa heat shock protein expression with adaptation to aspirin in rat gastric mucosa.

It is well documented that gastric mucosa can increase its resistance to mucosal damage caused by aspirin during repeated long-term administration of aspirin. However, the underlying mechanism of this adaptation is not well established. In the present study, we investigated the effect of long-term (chronic) administration of aspirin on expression of heat shock proteins (HSPs), which are known as endogenous cytoprotectants, in rat gastric mucosa. Rats were administered aspirin (100 mg/kg) daily for up to 20 days. After various periods of aspirin administration, a high dose of aspirin (250 mg/kg) was administered, and the mucosal damage was assessed. Expression of heat shock proteins (HSPs) in gastric mucosa was evaluated by Western blot. Intracellular localization of each HSP was studied immunohistochemically. Prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) levels were also investigated. Long-term aspirin administration resulted in development of resistance to aspirin-induced mucosal damage, and the increase of HSP72 expression correlated with mucosal resistance to aspirin. No significant increase was observed in HSP60 and HSP90 levels. Immunohistochemical study showed an increase of HSP72 in the cytoplasm of mucosal surface cells. The PGE2 level was suppressed and no change in the level of LTB4 was observed. It is possible that HSP72 could play important roles in gastric mucosal adaptation when the PGE2 level is suppressed by NSAIDs.

Tauroursodeoxycholic acid enhances phagocytosis of the cultured rat Kupffer cell.

BACKGROUND: Ursodeoxycholic acid is used in the treatment of acute and chronic intrahepatic cholestasis because it ameliorates cholestasis and protects hepatocytes. However, few studies have examined the effect of bile acids on the function of Kupffer cells. METHODS: The effect of various bile acids on cultured rat Kupffer cells was studied in terms of phagocytic activity in response to latex particles and morphological alterations. Video-enhanced differential interference contrast microscopy was used. RESULTS: Taurochenodeoxycholic acid and taurodeoxycholic acid reduced the number of latex particles incorporated into Kupffer cells, but taurocholic and tauroursodeoxycholic acids enhanced phagocytosis of latex particles. Inhibition of phagocytosis by taurochenodeoxycholic acid or taurodeoxycholic acid was essentially dose dependent. Tauroursodeoxycholic acid also enhanced phagocytosis by Kupffer cells in which phagocytosis had been reduced by pretreatment with taurochenodeoxycholic acid or taurodeoxycholic acid. Incorporated latex particles had a distinct translocation speed of 0.084+/-0.024 microm/s (mean maximum speed+/-SD); the speed was in the same range with tauroursodeoxycholic acid treatment. Tauroursodeoxycholic acid induced a 56% expansion of cytoplasm, associated with increased ruffling and movement of intracellular organelles. CONCLUSIONS: These observations suggest that tauroursodeoxycholic acid enhances membrane trafficking without changing translocation speed.

Color Doppler findings of tumor seeding after US-guided liver tumor biopsy.

We present two cases with tumor seeding along the needle tract occurring after a large-core needle liver tumor biopsy performed at other hospitals. Color Doppler sonography showed the hypervascular nature of the lesion and increased diagnostic confidence.

Splenic lymphangioma: US and CT diagnosis and clinical manifestations.

BACKGROUND AND METHODS: We tried to determine the role and problems of gray-scale sonography (US), computed tomography (CT), and color Doppler sonography in the diagnosis of splenic lymphangioma on the basis of our experience with seven adult cases with this relatively rare tumor. RESULTS: (1) The whole spleen was replaced by a collection of cysts of different sizes with or without calcifications in six patients. In these patients, color Doppler sonography showed the intrasplenic arteries and veins running along the cyst walls. (2) The enlarged spleen occupied the whole upper abdomen and contained numerous small cysts in one patient. The patient was initially diagnosed as having a pancreatic tumor because of the location, but color Doppler sonography clearly demonstrated two vessels (artery and vein) running parallel from the center of the mass. This characteristic vascular structure led to the determination that the mass was the markedly enlarged spleen. (3) The splenic lesion was isolated in six patients but was associated with mesenteric and pleural lymphangioma in one symptomatic patient. CONCLUSIONS: (1) When US shows multiple cysts of different sizes in the spleen, the diagnosis of splenic lymphangioma is not difficult to make with US and CT alone. (2) Color Doppler sonography is a very useful tool to increase diagnostic confidence because it demonstrates the vasculature of the mass. (3) When examining patients with splenic lymphangioma, one should consider the possibility of multiorgan involvement.

Color Doppler sonography of the gastroepiploic vein.

The gastroepiploic vein (GEV) may serve as a collateral circulation associated with splenic vein thrombosis. Despite the extensive literature on its computed tomographic and angiographic findings, there is no description of color Doppler findings of the GEV. We report scanning techniques for observing its entire course. When examining patients with pancreatic disease, familiarity with these color Doppler findings could help in the detection of not only splenic vein thrombus but also the GEV and may contribute to patient management.

Assessment of resectability of pancreatic carcinoma by color Doppler sonography.

This study was undertaken to evaluate the role of color Doppler sonography in the preoperative assessment of vascular involvement in patients with pancreatic carcinoma. Twenty-six pancreatic carcinomas were investigated with color Doppler sonography and angiography, and the results of these examinations were compared with those of surgical findings. Color Doppler sonography was more sensitive than angiography in depicting vascular involvement of carcinoma. Thus, it seems rational to perform a preoperative assessment in suspected pancreatic carcinoma patients initially with color Doppler sonography to improve patient management.

Helicobacter pylori-dependent ceramide production may mediate increased interleukin 8 expression in human gastric cancer cell lines.

BACKGROUND & AIMS: Helicobacter pylori adheres to gastric epithelial cells, activates nuclear factor kappaB (NF-kappaB), and stimulates interleukin (IL)-8 production, but the responsible molecular mechanisms remain largely unknown. Because several studies have shown that sphingolipids are involved in a number of signaling pathways, including NF-kappaB activation, we investigated the possible role of sphingolipids in the regulation of IL-8 expression in Kato III and AGS cells. METHODS: IL-8 production in the conditioned media was quantified by enzyme immunoassay. Induction of messenger RNA (mRNA) was assessed by Northern blot analysis. Activation and binding activity of transcription factors were examined by luciferase assay and electrophoretic mobility shift assay, respectively. Intracellular levels of ceramide were quantified by diacylglycerol kinase assay. RESULTS: A cell-permeable ceramide analogue (C2-ceramide) increased IL-8 expression with comparable mRNA induction. This effect was mimicked by sphingomyelinase, but not by phospholipase A2 or phospholipase C. C2-ceramide induced IL-8 gene transcription mainly through activation of NF-kappaB because mutation of the NF-kappaB-binding site completely abrogated the induction of luciferase activity. Direct contact of live H. pylori with epithelial cells increased the intracellular concentration of ceramide. CONCLUSIONS: The results suggest a novel role of the sphingomyelin-ceramide pathway, at least in part through NF-kappaB, in IL-8 production induced by H. pylori infection in gastric epithelial cells.

Primary biliary cirrhosis associated with membranous glomerulonephritis.

A 33-year-old woman was admitted to our department for evaluation of liver dysfunction and proteinuria. A liver biopsy specimen showed ductular proliferation and moderate portal fibrosis indicating stage II primary biliary cirrhosis. A renal biopsy specimen showed mild to moderate mesangial cell proliferation without crescent formation or interstitial nephritis. Immunofluorescent staining revealed deposition of immunoglobulin G (IgG), third component of complement (C3), and Clq on glomerular basement membranes. The findings indicated stage I membranous glomerulonephritis. Administration of ursodesoxycholic acid together with prednisolone, azathioprine, and dipyridamole decreased proteinuria and improved cholestatic liver dysfunction.

Hepatic hemangioma with arterioportal shunts.

Color Doppler sonograms and angiographic findings in 23 hepatic hemangioma patients were compared to clarify how arterioportal shunts influence color Doppler findings of hepatic hemangiomas. The results of our study showed that the presence of arterioportal shunts (six cases) gave rise to large feeding arteries (five cases), multiple intratumoral flows (six cases), and reversal of portal flow within (five cases) or around (four cases) the tumor. These color Doppler findings mimicked hypervascular malignant tumors. Knowledge of such unusual color Doppler findings in hepatic hemangiomas may help in avoiding misinterpretations of color Doppler sonograms.

Microbiology of the intestinal lymph follicle: a clue to elucidate causative microbial agent(s) in Crohn's disease.

It has been suggested that microbial agent(s) are involved in the onset of Crohn's disease. None of the candidates, however, has been unequivocally demonstrated to be a causative agent. The macroscopically earliest lesion takes place in the lymph follicle, irrespective of the initial attack or relapse in Crohn's disease. Human leucocyte antigen-DR (HLA-DR) antigens are expressed on the epithelium around the lymph follicle even in areas endoscopically uninvolved in Crohn's disease. These observations make the lymph follicle critical in the onset of Crohn's disease. The lymph follicle is a port of entry of a variety of microbial agent(s), leading to the speculation that microbial agent(s) exist in the lymph follicle. Polymerase chain reaction (PCR) using universal primers designed from conserved regions of bacterial ribosomal RNA or techniques such as representational difference analysis, may well identify microbial agent(s) in the lymph follicle that are specific to Crohn's disease. The existence of bacteria in the lymph follicle is here indicated by preliminary studies.