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Biomedical subjects

Y Gotoh

Publications and source records attributed to Y Gotoh.

At least 37 records · Page 2Linked to original sources
PubMed2001

Epinephrine irrigation for the prevention of pancreatic damage after endoscopic balloon sphincteroplasty.

BACKGROUND AND AIM: Endoscopic balloon sphincteroplasty (EBS) is an alternative to sphincterotomy for the treatment of bile duct stones. The purpose of this study was to determine if epinephrine irrigation of the papilla can prevent the pancreatic damage associated with EBS. METHODS: A total of 173 patients with bile duct stones were treated by EBS. After conventional endoscopic retrograde cholangiography, EBS was performed by using a biliary dilatation catheter (balloon diameter: 8 mm). The duct was then cleared by using Dormia baskets or retrieval balloon catheters. Mechanical lithotripsy was performed before extraction when the stones were greater than 8 mm in diameter. In 81 patients, the dilated orifice was irrigated with 40-120 mL (50 +/- 37 mL) of 1:1,000,000 epinephrine (epinephrine group). In the remaining 92 patients, epinephrine irrigation was not performed (control group). Acute pancreatitis was defined by a serum amylase concentration fivefold greater than the upper limits of normal in association with abdominal pain. RESULTS: After EBS, serum amylase concentrations were significantly increased in both groups. However, the degree of hyperamylasemia was less in the epinephrine group than in the control group (617 +/- 611 vs 1037 +/- 1491 IU/L, P < 0.05). The incidence of pancreatitis was lower in the epinephrine group than in the control group (1.2 vs 7.6%, P < 0.05). CONCLUSIONS: Epinephrine irrigation is a simple and useful method to prevent post-EBS pancreatic damage and pancreatitis.

Adult↗
PubMed2001

Programmed cell death in rat intestine: effect of feeding and fasting.

BACKGROUND: The regulation of intestinal cell death by luminal factors is poorly understood. The objectives of this study were to determine whether a diurnal rhythm of intestinal apoptosis exists, and to determine the role that feeding and fasting play in this process. METHODS: Mucosal apoptotic death was measured in fed and 24-h fasted rats and at various times after feeding by DNA fragmentation and in situ immunohistochemical staining (TUNEL). RESULTS: In 24-h fasted rats, 32% of total mucosal DNA was fragmented as compared to 9% in fed animals. In both jejunal and ileal segments, the fragmented DNA exhibited characteristic apoptotic DNA ladders on agarose gels. Immunohistochemical staining revealed significant location of apoptotic cells at the upper third of the intestinal villus. In the duodenum, DNA fragmentation at 6-12 h post feeding was 20% and decreased to 4% at 24 h. In comparison, DNA fragmentation in the jejunum and ileum was low from 0 to 6 h post feeding (2%-9%) and significantly increased at 12 h (18% versus 12%) and 24 h (30% versus 32%), respectively. These results are consistent with a temporal relationship between percent fragmented DNA and time after feeding with greater cell death at longer fasting period. A postprandial rhythm of DNA fragmentation was evident in the jejunum and ileum, in which fragmentation was at a peak between 0900 h and 1200 h. CONCLUSION: Collectively, the data show that initiation of apoptosis in apical enterocytes is coincident with cessation of feeding and commencement of fasting, and is consistent with a rhythm of programmed cell death in these cells that parallels the cyclical pattern of feeding and fasting.

Animals↗
PubMed2001

Dehydroascorbic acid and oxidative stress in haemodialysis patients.

BACKGROUND: The amount of dehydroascorbic acid contained within total ascorbic acid (oxidized as well as non-oxidized forms) in plasma, hereafter referred to as the dehydroascorbic acid fraction, may be a measure of oxidative stress during haemodialysis. In the present study, we determined this fraction in chronic haemodialysis patients. METHODS: Using high performance liquid chromatography, dehydroascorbic acid and total ascorbic acid levels were measured in 80 maintenance haemodialysis patients for a period of > 2 years as well as in 49 controls, to examine a possible association of these compounds with clinical parameters and/or drugs taken by the patients. RESULTS: Dialysis patients who had an increased plasma urate level (P < 0.05) and had been taking allopurinol (P < 0.05) or NSAID (non-steroid anti-inflammatory drugs) (P < 0.01), and dialysis patients who were younger (< or = 55 years), as compared with older dialysis patients (P < 0.01), were found to have a lower dehydroascorbic acid fraction by multivariate analysis. Mean plasma dehydroascorbic acid levels and dehydroascorbic acid fractions were significantly lower in the younger haemodialysis patients (4.8 +/- 0.7 micromol/l and 28.4 +/- 3.9%) than in healthy younger controls (13.3 +/- 1.1 micromol/l and 41.1 +/- 1.8%) (P < 0.0001 and P < 0.01, respectively). Moreover, a correlation was found between plasma dehydroascorbic acid fraction and plasma lipid peroxide (r = 0.66, P < 0.01) in patients who had not been taking allopurinol and/or NSAID. CONCLUSION: We found that dehydroascorbic acid fraction was related to patients' age, plasma urate level and to taking allopurinol or NSAID. Dehydroascorbic acid fraction may be another indirect index of oxidative stress.

Aging↗
PubMed2001

Bone formation by transplanted human osteoblasts cultured within collagen sponge with dexamethasone in vitro.

To apply osteoblasts to bone reconstruction, we proved that transplanted osteoblasts possessed the differentiated osteoblastic function and formed bonelike tissue in vivo after transplantation. First, we confirmed that dexamethasone (Dex) promoted the expression of osteoblastic phenotype in human osteoblast culture using reverse-transcription-polymerase chain reaction (RT-PCR). These osteoblasts were cultured for 10 days within collagen sponge, which consists of denatured type I collagen, in the presence or absence of 10(-7) M Dex. The osteoblasts along with collagen sponge were transplanted into the trapezius muscles of 8-week-old severe combined immunodeficiency (SCID) mice, and the transplants were harvested at 2, 4, 6, and 8 weeks. At 2 weeks, Dex-treated osteoblasts formed bonelike tissue, the quantity of which increased in a time-dependent manner to 8 weeks. This bonelike tissue was composed of mineralized collagen matrix newly synthesized by the transplanted osteoblasts. This mineralized matrix was separated from the osteoblasts by nonmineralized matrixlike osteoid. Furthermore, many osteocytic cells were observed in this mineralized matrix. A high expression of alkaline phosphatase (ALPase) and osteocalcin was detected in the transplanted cells surrounding the bonelike tissue. In situ hybridization for human-specific alu sequence indicated that newly formed bone was of donor origin. The transplants of nontreated cells failed to form bonelike tissue. The transplants of collagen sponge alone formed no bonelike tissue. These studies indicate that Dex-treated human osteoblasts possess the differentiated osteoblastic function and are able to form bone tissue in vivo. These new findings are of use in facilitating the application of osteoblasts to bone reconstruction.

Alkaline Phosphatase↗
PubMed2001

Impaired IL-15 production associated with susceptibility of murine AIDS to mycobacterial infection.

LP-BM5 murine leukemia virus (MuLV) injection causes murine AIDS (MAIDS), a disease characterized by many functional abnormalities of immunocompetent cells. We show that MAIDS mice are susceptible to Mycobacterium bovis Bacille Calmette-Guérin (BCG) infection as assessed by survival rate and bacterial counts. The peritoneal exudate macrophages from MAIDS mice produced a significant level of interleukin (IL)-12 soon after inoculation with BCG, whereas IL-15 and tumor necrosis factor (TNF) production were severely impaired in BCG-infected MAIDS mice. The appearance of natural killer (NK) and CD4+ T helper type 1 (Th1) cells specific for mycobacterial antigen were depressed in MAIDS mice after BCG infection. Thus, it appeared that impaired production of IL-15, besides other inflammatory cytokines, in MAIDS mice may be involved in the poor responses of the NK and Th1 cells, resulting in an increased susceptibility to BCG.

Animals↗
PubMed2001

[The new portable system for home enteral nutrition, Portermate, made a patient possible go out for a long time: report of a case].

The patient, who is received home enteral nutrition (HEN) for a long time in a day, has problems on moving all days. Now, we tried Portermate, which is new portable devices for HEN, in his clinical care. The patient is chronic pancreatitis, and his clinical problems becomes to be worse after he ate. He was under total enteral nutrition via jejunostomy. His clinical complications were almost controlled after HEN, but he has a few complains receiving enteral nutrition. He would not move easily, for an old HEN system was not compact to move. Portermate made him go everywhere he wanted any time. It extremely improved his QOL under HEN. He continues to use Portermate.

Activities of Daily Living↗
PubMed2000

Intersubunit location of the active site of farnesyl diphosphate synthase: reconstruction of active enzymes by hybrid-type heteromeric dimers of site-directed mutants.

Farnesyl diphosphate synthase is a homodimer of subunits having typically two aspartate-rich motifs with two sets of substrate binding sites for an allylic diphosphate and isopentenyl diphosphate per molecule of a homodimeric enzyme. To determine whether each subunit contains an independent active site or whether the active sites are created by intersubunit interaction, we constructed several expression plasmids that overproduce hybrid-type heterodimers of Bacillus stearothermophilus FPP synthases constituting different types of mutated monomers, which exhibit little catalytic activity as homodimers, by combining two tandem fps genes for the manipulated monomer subunit with a highly efficient promoter trc within an overexpression pTrc99A plasmid. A heterodimer of a combination of subunits of the wild type and of R98E, a mutant subunit which exhibits little enzymatic activity as a dimer form (R98E)(2), exhibited 78% of the activity of the wild-type homodimer enzyme, (WT)(2). Moreover, when a hybrid-type heterodimeric dimer of FPP synthase mutant subunits (R98E/F220A) was prepared, the FPP synthase activity was 18- and 390-fold of that of each of the almost inactive mutants as a dimeric enzymes, (R98E)(2) and (F220A)(2) [Koyama, T., et al. (1995) Biochem. Biophys. Res. Commun. 212, 681-686], respectively. These results suggest that the subunits of the FPP synthase interact with each other to form a shared active site in the homodimer structure rather than an independent active site in each subunit.

Alkyl and Aryl Transferases↗
PubMed2000

Percutaneous recanalization of the bile duct along an endoscopic naso-biliary catheter.

Percutaneous recanalization of the bile duct is essential for placing biliary stents and carrying out other interventions. This prospective study was performed to establish safe approaches for percutaneous recanalization of the bile duct when it had previously resulted in failure. Between July 1995 and July 1999, percutaneous recanalization of the bile duct was attempted in 58 patients with a malignant biliary stenosis. When recanalization failed, an endoscopic naso-biliary drainage (ENBD) catheter was placed across the stenosis. The procedure was again attempted along the ENBD catheter. In the period of the study, four patients underwent successful recanalization after ENBD, although attempts prior to ENBD had been unsuccessful. As a result, the success rate of recanalization in the period was 100% (58/58). When recanalization fails, the use of an ENBD catheter may provide access to the biliary tree, and the biliary stenosis can be recanalized safely.

Abdominal Neoplasms↗
PubMed2000

Fluid viscosity of Aureobasidium pullulans cultures obtained at two different initial pH values.

Aureobasidium pullulans IAM 5060 grown in media with initial pHs of 6 and 7 differed in its production of exopolysaccharides (EPS). Under the latter condition, EPS of a high molecular weight was produced in an especially large amount. The viscosity of the culture broths and the EPS solutions obtained by removing the microbial cells exhibited a marked non-Newtonian and complex behavior depending on the measurement method. The nature of the viscosity of the fluids is explained by means of several structural models of their constitutive particles.

Journal Article↗
PubMed2000

Access for percutaneous transhepatic cholangioscopy in patients with nondilated bile ducts using nasobiliary catheter cholangiography and oblique fluoroscopy.

BACKGROUND: Percutaneous transhepatic biliary drainage is required for percutaneous transhepatic cholangioscopy. However, puncture of nondilated bile ducts under ultrasonographic guidance is difficult. METHODS: In 10 patients with no ultrasonographic evidence of intrahepatic bile duct dilatation, percutaneous transhepatic biliary drainage was performed under fluoroscopic guidance using cholangiography obtained via a nasobiliary drainage catheter. Direct puncture was performed by means of a left ventral approach using oblique C-arm fluoroscopy. RESULTS: Bile duct puncture was successful in all patients. There were no procedure-related complications. Subsequent cholangioscopy was successful in all patients. CONCLUSIONS: Direct puncture using nasobiliary drainage cholangiography and oblique fluoroscopy is a useful method when cholangioscopy is necessary in patients with nondilated bile ducts.

Adult↗
PubMed2000

Detection of interleukin-12 (IL-12)-secreting cells in normal mice with enzyme-linked immunospot (ELISPOT) assay.

To assess mice interleukin-12 (IL-12)-secreting cells at a single cell level, we have developed a murine IL-12 specific enzyme-linked immunospot (ELISPOT) assay. The application of the newly developed method clearly showed the frequency of IL-12-secreting cells in the resident peritoneal exuded cells was higher than other organs of normal DBA/1J mouse. Moreover, we determined the frequency of IL-12-secreting cells in the spleens of five strains of inbred mice, and found the incidence of IL-12 secretors in the strain C57BL/6 to be greatest, and significantly greater than four of the others. These results are compatible with the predicted evidence, supporting this ELISPOT assay for IL-12-secreting cells is accurate. The procedure provides a useful tool for investigating complicated immune responses at a single cell level.

Animals↗
PubMed2000

Characterization of the cytokine network at a single cell level in mice with collagen-induced arthritis using a dual color ELISPOT assay.

Collagen-induced arthritis (CIA) in mice has been classified as a Thl-mediated disease. However, most evidence for this has been obtained by indirect experiments; for example, the administration of neutralizing anti-interferon-gamma (IFN-gamma) antibody reduced the severity of arthritis. To obtain direct evidence about the cytokine balance in CIA mice, we analyzed the cytokine-secreting cell in CIA mice at the single cell level using a dual color enzyme-linked immunospot (ELISPOT) assay, which enabled us to analyze interleukin-2 (IL-2)-secreting cells or IL-4-secreting cells or both simultaneously. Furthermore, to characterize the cytokine network in the pathogenesis of CIA, the frequency of the cells secreting IL-12, which induced the development of naive Th cells into Th1 cells, was analyzed. The results show that in the prearthritic phase, the number of IL-12-secreting cells in spleen and peritoneal exuded cells is increased, and Th1 cells in lymph node and spleen are dominant. In contrast, after the onset of clinical arthritis, the number of IL-12-secreting cells in spleen, lymph node, and peritoneal exuded cells is decreased, and there is a shift from a Thl-dominant to a Th2-dominant state in lymph node and spleen. The results indicated that the pathogenesis of CIA is associated with a disruption in the normal ratio of Th1/Th2 at cell level.

Animals↗
PubMed2000

Lipid hydroperoxide-induced apoptosis in human colonic CaCo-2 cells is associated with an early loss of cellular redox balance.

Apoptosis plays a critical role in maintaining homeostasis of the intestinal epithelium. Dietary oxidants like peroxidized lipids could perturb cellular redox status and disrupt mucosal turnover. The objective of this study was to delineate the role of lipid hydroperoxide (LOOH) -induced redox shifts in intestinal apoptosis using the human colonic CaCo-2 cell. We found that subtoxic concentrations of LOOH increased CaCo-2 cell apoptosis. This LOOH-induced apoptosis was associated with a significant decrease in the ratio of reduced glutathione-to-oxidized glutathione (GSH/GSSG), which preceded DNA fragmentation by 12 to 14 h, suggesting a temporal relationship between the two events. Oxidation of GSH with the thiol oxidant diamide caused significant decreases in cellular GSH and GSH/GSSG at 15 min that correlated with the activation of caspase 3 (60 min) and cleavage of PARP (120 min), confirming a temporal link between induction of cellular redox imbalance and initiation of apoptotic cell death. These kinetic studies further reveal that oxidant-mediated early redox change (within 1 h) was a primary inciting event of the apoptotic cascade. Once initiated, the recovery of redox balance did not prevent the progression of CaCo-2 cell apoptosis to its biological end point at 24 h. Collectively, the study shows that subtoxic levels of LOOH disrupt intestinal redox homeostasis, which contributes to apoptosis. These results provide insights into the mechanism of hydroperoxide-induced mucosal turnover that have important implications for understanding oxidant-mediated genesis of gut pathology.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2000

Experimental use of fibrin glue to induce site-directed osteogenesis from cultured periosteal cells.

The purpose of this study was to determine whether a combination of fibrin glue and cultured periosteal cells will result in new bone formation at heterotopic sites in nude mice. Growing cells and developing matrices surrounding periosteal explants from the diaphyses of radii of newborn calves were minced and mixed with fibrin glue in a syringe. The cell/matrix-fibrin glue admixture was then injected into the subcutaneous space on the dorsum of athymic nude mice. After 12 weeks of implantation, gross morphology and histologic investigations showed newly formed bone structures in all cell/matrix-fibrin glue admixtures, but none in fibrin glue injected alone and used as control samples. Osteopontin, a protein important in bone development, was identified by a Western blot assay of the cell/matrix-fibrin glue composite. This study supports the feasibility of initiating site-directed formation of bone structures at heterotopic tissue sites by means of injection of cultured periosteal cells and matrix in a fibrin glue carrier.

Animals↗
PubMed2000

Involvement of an organic anion transporter (canalicular multispecific organic anion transporter/multidrug resistance-associated protein 2) in gastrointestinal secretion of glutathione conjugates in rats.

We investigated the role of cMOAT/MRP2 (canalicular multispecific organic anion transporter/multidrug resistance-associated protein 2) in the intestinal secretion of organic anions by comparing the behavior in Sprague-Dawley (SD) rats and Eisai hyperbilirubinemic rat (EHBR) whose cMOAT/MRP2 is hereditarily defective. After i.v. administration of 1-chloro-2,4-dinitrobenzene (30 micromol/kg), the biliary and intestinal excretion of its glutathione conjugate 2, 4-dinitrophenyl-S-glutathione (DNP-SG), a substrate for cMOAT/MRP2, was significantly reduced in EHBR compared with SD rats. This result also was confirmed by Ussing chamber studies; DNP-SG showed 1.5-fold greater serosal-to-mucosal flux compared with the mucosal-to-serosal flux in SD rats, whereas a similar flux was observed in both directions in EHBR. In addition, metabolic inhibitors reduced the preferential serosal-to-mucosal flux of DNP-SG in SD rats. In everted sac studies, intestinal secretion clearance, defined as the efflux rate of DNP-SG into the mucosal side divided by the area under the curve on the serosal side, was significantly lower in the jejunum of EHBR than that in SD rats. Northern blot analyses demonstrated the highest mRNA level of cMOAT/MRP2 in the jejunum, which is in good agreement with the results of the everted sac studies. These results suggest that cMOAT/MRP2 is involved in the secretion of organic anions in the small intestine.

ATP-Binding Cassette Transporters↗
PubMed1999

Requirement for mitogen-activated protein kinase in cerebellar long term depression.

The mitogen-activated protein kinase (MAPK) cascade has been shown to play an essential role in regulation of cell proliferation and cell differentiation. Although mammalian MAPKs are most abundantly expressed in postmitotic and terminally differentiated neuronal cells, their function in the central nervous system is still largely undefined. We present evidence here for a role of the MAPK cascade in cerebellar long term depression (LTD), which is a widely studied form of synaptic plasticity in mammalian brain. In cultured Purkinje cells, LTD is known to be induced by iontophoretic application of glutamate and depolarization of Purkinje cells. We found that MAPK was activated in Purkinje cells by treatment of primary cultures of rat embryonic cerebella with glutamate and a depolarization-inducing agent, KCl. Application of PD98059, a specific inhibitor of MAPK kinase (MAPKK/MEK), inhibited both the activation of MAPK and the induction of LTD in Purkinje cells. Furthermore, the induction of LTD was completely blocked by introduction into Purkinje cells of anti-active MAPK antibody, which was found to specifically and potently inhibit the activity of MAPK. These results suggest that postsynaptic activation of the MAPK cascade is essential for the induction of cerebellar LTD.

Animals↗