Biomedical subjects

M Ogawa

Publications and source records attributed to M Ogawa.

At least 91 records · Page 5Linked to original sources

PubMed2001

Predicting the reactivity of proteins from their sequence alone: Kazal family of protein inhibitors of serine proteinases.

An additivity-based sequence to reactivity algorithm for the interaction of members of the Kazal family of protein inhibitors with six selected serine proteinases is described. Ten consensus variable contact positions in the inhibitor were identified, and the 19 possible variants at each of these positions were expressed. The free energies of interaction of these variants and the wild type were measured. For an additive system, this data set allows for the calculation of all possible sequences, subject to some restrictions. The algorithm was extensively tested. It is exceptionally fast so that all possible sequences can be predicted. The strongest, the most specific possible, and the least specific inhibitors were designed, and an evolutionary problem was solved.

Algorithms↗

PubMed2001

Citrullinemia type II in a 64-year-old man with fluctuating serum citrulline levels.

We describe a 64-year-old man with 'citrullinemia type II' whose serum citrulline levels fluctuated between normal and abnormally high during episodic manifesting periods. Elevations of the serum threonine/serine ratio and pancreatic secretory trypsin inhibitor level are very useful diagnostic markers. Our patient's cerebrospinal fluid citrulline level was also elevated, and T1-weighted magnetic resonance images revealed high-intensity signals at the bilateral internal capsule and the cerebral peduncles. Single-photon emission computed tomography of his brain showed reduced bilateral temporal lobar blood flow. Even if the serum citrulline level is within the normal range, citrullinemia should be considered in adult patients without primary liver dysfunction who show episodic consciousness disturbance, psychotic symptoms or both.

Ammonia↗

PubMed2001

High-speed separation system of randomly suspended single living cells by laser trap and dielectrophoresis.

We developed a new system for random separation of a single microorganism, such as a living cell and a microbe, in the microfluidic device under the microscope by integrating the laser-trapping force and dielectrophoretic (DEP) force. An arbitrarily selected single microbe could be isolated in a microchannel, despite the presence of a large number of microbes in solution. Once the target microbe is trapped at the focal point of the laser, we can easily realize exclusion of excess microbes around the target by controlling the electric field, while keeping the target trapped by the laser at the focal point. To realize an efficient separation system, we proposed a new separation cell and produced it by microfabrication. Flow speed in the microchannel is adjusted and balanced to realize high-speed and high-purity extraction of the target. Some preliminary experiments are conducted to show the effectiveness. The target is trapped by the laser, transported, and is taken out from the extraction port. Total separation time is less than 20 s. Our method is extremely useful in the pure cultivation of the cell and will be a promising method for biologists in screening useful microbes.

Cell Separation↗

PubMed2001

Nerve growth factor signaling of p75 induces differentiation and ceramide-mediated apoptosis in Schwann cells cultured from degenerating nerves.

In peripheral nerve regeneration or remyelination, immature Schwann cells expressing p75(NTR) play cardinal roles in the support and regeneration of axons (Griffin JW, Hoffman PN. Peripheral Neuropathy 361-376, 1993). Only one of four to six Schwann cells participate in remyelination of damaged or regenerating axons. The rest of the cells, or supernumerary Schwann cells, show severe atrophy and gradually decrease in number, reestablishing a 1:1 axon-Schwann cell relationship (Said G, Duckett S. Acta Neuropathol (Berl) 53:173-179, 1981). Recent reports demonstrated that severely atrophied supernumerary Schwann cells are eliminated by apoptosis during axonal regeneration or remyelination (Hirata H, Hibasami H. Apoptosis 3:353-360, 1998; Berciano MT, Calle E. Acta Neuropathol (Berl) 95:269-279, 1998). The mechanism to induce selective death of supernumerary Schwann cells without causing any damage to axon-associated Schwann cells or axons remains to be determined. In this article, we report that p75(NTR), the low-affinity receptor for all members of neurotrophins, signals both cell differentiation and apoptosis through intracellular ceramide elevation. The final response is dependent on the intracellular ceramide level and Schwann cells modulate their response by changing expression level of p75(NTR). This effect was selective for nerve growth factor (NGF). Taken together, the present study suggests that NGF contributes both to phenotypic regulation and to elimination of the dedifferentiated Schwann cells, while supporting survival or regeneration of certain types of axons during peripheral nerve repair or regeneration.

Animals↗

PubMed2001

In vivo binding properties of [carbonyl-11C]WAY-100635: effect of endogenous serotonin.

[Carbonyl-(11)C]WAY-100635 has been reported to be a useful ligand for the investigation of 5-HT(1A) receptor imaging in vivo. However, the cellular distribution and the influence of endogenous serotonin (5-HT) on in vivo binding have not been fully examined. In this study, we investigated the effect of 5,7-dihydroxytryptamine-produced destruction of 5-HT neurons, reserpine-induced 5-HT depletion, and fenfluramine-induced 5-HT increase on [carbonyl-(11)C]WAY-100635 binding in vivo. There was no significant change in the uptake of [carbonyl-(11)C]WAY-100635 in the slice of 5-HT denervated rat brain except in the raphe nucleus, where 5-HT cell bodies exist. There was no obvious effect of enhanced 5-HT release by fenfluramine or decreased release by reserpine on [carbonyl-(11)C]WAY-100635 binding in the dissected brain region. No significant effect was observed in the time course of [carbonyl-(11)C]WAY-100635 in the hippocampus and frontal cortex measured by PET. These results indicated that the in vivo binding of [carbonyl-(11)C]WAY-100635 in the hippocampus and cerebral cortex mainly reflects postsynaptic 5-HT(1A) receptor binding, and that this binding is not sensitive to endogenous 5-HT.

5,7-Dihydroxytryptamine↗

PubMed2001

A serine protease inhibitor, N-alpha-tosyl-l-lysine chloromethyl ketone, prolongs rat hepatic allograft survival.

BACKGROUND: Serine protease inhibitors have profound suppressive effects on cellular and humoral immune responses. We investigated the effect of a serine protease inhibitor, N-alpha-tosyl-l-lysine chloromethyl ketone (TLCK), on hepatic allograft survival in rats. Methods. Orthotopic hepatic transplantation was performed in an ACI (RT1(a))-to-LEW (RT1(1)) rat combination. TLCK was administered continuously at a dose of 4.4 mg/kg/day using an osmotic subcutaneous infusion minipump. RESULTS: TLCK prolonged hepatic allograft survival. Histologic staging of acute rejection based on Banff criteria in TLCK-treated hepatic allografts was significantly lower than in untreated allografts. TLCK significantly reduced serum concentrations of interferon (IFN)-gamma and tumor necrosis factor (TNF) alpha in allograft recipients. TNF-alpha mRNA levels in TLCK-treated allografts were significantly lower than in untreated allografts. TLCK also decreased perforin mRNA levels in hepatic allografts. Hepatic infiltrates eluted from TLCK-treated allografts showed significantly lower cell-mediated lympholytic activity against donor Con A blast cervical lymph node cells than those from untreated allografts. In vitro, TLCK suppressed interleukin-2 production and [(3)H]thymidine incorporation into an allogeneic mixed lymphocyte reaction. CONCLUSION: TLCK suppressed acute allograft rejection, suggesting a novel immunosuppressive strategy for therapy of acute organ rejection.

Animals↗

PubMed2001

Differential splenic migration of dendritic cells after immunologic unresponsiveness in rat hepatic allografts induced by pretransplant donor-specific transfusion.

BACKGROUND: Donor dendritic cells migrate into the recipient spleen after hepatic transplantation. We previously reported that immunologic unresponsiveness to rat hepatic allografts can be induced by prior donor-specific blood transfusion (DST). We investigated the phenotype and splenic distribution of donor dendritic cells after allografting and DST. METHODS: Donor dendritic cells were identified with anti-rat dendritic cell (OX-62) and anti-donor class II MHC (RT1B(a)) (OX-76) antibodies. The phenotype of dendritic cells was determined with antibodies to CD45RC, CD62L, and the maturation markers CD80 (B7-1) and CD86 (B7-2). The cytokine profile of sorted CD45RC(+) OX-62(+) and CD45RC(-) OX-62(+) dendritic cells was analyzed by reverse transcription polymerase chain reaction (RT-PCR). RESULTS: Pretransplant DST significantly prolonged rat hepatic allograft survival. Immunostaining revealed OX76(+)/OX-62(+) cells in the splenic red pulp of animals receiving pretransplant DST and in the white pulp of untreated animals after transplantation. The ratio of splenic CD45RC(-) OX-62(+) cells to CD45RC(+) OX-62(+) cells was significantly higher in DST recipients than in untreated animals. CD62L, CD80, and CD86 were lower on CD45RC(-) OX-62(+) than CD45RC(+) OX-62(+) cells. RT-PCR revealed that sorted CD45RC(-) OX-62(+) cells expressed interleukin (IL)-4 and IL-10. In contrast, sorted CD45RC(+) OX-62(+) cells expressed only IL-2 and interferon gamma (IFN-gamma). CONCLUSION: Differential splenic migration of CD45RC(-) dendritic cells is associated with immunologic unresponsiveness to rat hepatic allografts.

Animals↗

PubMed2001

Nestin-EGFP transgenic mice: visualization of the self-renewal and multipotency of CNS stem cells.

We generated transgenic mice carrying enhanced green fluorescent protein (EGFP) under the control of the nestin second-intronic enhancer (E/nestin:EGFP). Flow cytometry followed by in vitro assays revealed that in situ EGFP expression in the embryonic brain correlated with the mitotic index, the cogeneration of both neurons and glia, and the frequency of neurosphere formation in vitro. High-level EGFP expressors derived from embryos included a distinct subpopulation of cells that were self-renewable and multipotent, criteria that define neural stem cells (NSCs). Such cells were largely absent among lower-level or non-EGFP expressors, thereby permitting us to enrich for NSCs using EGFP expression level. In adults, although E/nestin:EGFP-positive cells included the NSC population, the frequency of neurosphere formation did not correlate directly with the level of EGFP expression. However, moderately EGFP-expressing cells in adults gained EGFP intensity when they formed neurospheres, suggesting embryonic and adult NSCs exist in different microenvironments in vivo.

Animals↗

PubMed2001

A pharmacokinetic study of idarubicin in Japanese patients with malignant lymphoma: relationship with leukocytopenia and neutropenia.

To clarify the pharmacokinetic properties of idarubicin (IDA) in Japanese patients and to clarify the relationship between the pharmacokinetic parameters of IDA or idarubicinol (IDAol), an active metabolite of IDA, and leukocytopenia or neutropenia, we examined the pharmacokinetics of IDA in patients with malignant lymphoma. Nine of 21 patients registered in an early phase II study of IDA were enrolled in the pharmacokinetic study. IDA (12 or 15 mg/m2) was administered by intravenous infusion for 5 minutes. The elimination half lives (t 1/2) of IDA were 11.0 hours and 12.5 hours after administration of 12 and 15 mg/m2 IDA, respectively. IDAol appeared rapidly both in plasma and in blood cells, and its concentrations exceeded those of IDA within 4 hours. IDAol had a very long t 1/2 (69.2 hours and 70.0 hours for 12 and 15 mg/m2, respectively). The areas under the concentration curves of IDAol in plasma were 3.4 and 5.8 times higher than those of IDA after administration of 12 and 15 mg/m2 IDA, respectively. The t 1/2 of IDAol in plasma correlated significantly with the nadir of neutrophils, and the steady-state volume of distribution of IDA in plasma and in blood cells correlated significantly with the nadirs of white blood cells and neutrophils. These results suggest that both IDA and IDAol play an important role in leukocytopenia or neutropenia. No substantial differences between Japanese and Caucasian people in the pharmacokinetics of IDA were apparent.

Aged↗

PubMed2001

Involvement of three or more lymph nodes predicts poor prognosis in submucosal gastric carcinoma.

BACKGROUND: Multivariate analyses has shown that the status of lymph node metastasis and the depth of tumor penetration through the gastric wall are the most important prognostic factors in patients with advanced gastric carcinoma after curative operation. A clinicopathological study was carried out to clarify a simple and optimal prognostic indicator for early gastric cancer. METHODS: Retrospective analyses of 982 patients with early gastric cancer (562 with mucosal [M] and 420 with submucosal [SM] tumor) treated by gastrectomy with D2 lymph node dissection were performed. RESULTS: The incidence of lymph node metastasis from M and SM tumors was 2.5% (14/562) and 20.2% (85/420), respectively. There were no apparent prognostic indicators in patients with M tumors. In patients with SM tumors, the cancer-specific 5-year survival of those with lymph node metastasis was significantly lower than that of those without such metastasis (77.6% vs 98.2%; P < 0.001). An sharp decrease in survival was seen between patients with two positive nodes and those with three positive nodes, and the cancer-specific 5-year survival rate of patients with three or more metastatic lymph nodes was significantly lower than that of those with one or two nodes (P < 0.001; univariate analysis). Multivariate analysis revealed that the involvement of three or more lymph nodes was the sole independent prognostic determinant (P = 0.016); the level of nodal metastasis was not an independent prognostic factor (P = 0.384). All patients with N2 lymph node echelons (according to the Japanese Research Society for Gastric Cancer classification of the draining lymph nodes of the stomach) in the group with one or two positive nodes survived for more than 5 years. CONCLUSION: The sole independent prognostic factor in SM gastric cancer is the involvement of three or more metastatic lymph nodes. We suggest that this simple prognostic indicator for the follow-up of early gastric cancer, and this could lead to potentially effective adjuvant chemotherapy.

Adult↗

PubMed2001

Two novel genes encoding SNF-1 related protein kinases from Arabidopsis thaliana: differential accumulation of AtSR1 and AtSR2 transcripts in response to cytokinins and sugars, and phosphorylation of sucrose synthase by AtSR2.

We searched for genes encoding members of the group-3 SNF1-related protein kinase (SnRK3) family in the Arabidopsis thaliana database, and seven independent sequences were identified. Transcripts of two of them were found to accumulate differentially upon treatment with light, cytokinins and sugars. Full-length cDNAs were isolated and designated as AtSR1 and AtSR2; they encode polypeptides of 442 and 429 amino acids with relative molecular masses of 50.3 kDa and 48.2 kDa, respectively. In etiolated seedlings, no transcripts of either gene were observed. However, upon exposure to light or cytokinins, transcripts of AtSR1 but not AtSR2 began to accumulate. The induction with light was greatly reduced in the presence of a cytokinin antagonist, suggesting that cytokinins are involved in light-signaling pathways. In contrast, transcription of AtSR2, but not of AtSR1, was greatly increased by sucrose, as well as glucose and fructose. AtSR2 expressed in E. coli efficiently phosphorylated sucrose synthase in the presence of manganese ions. These results suggest that, although SnRK3 proteins may generally be involved in sugar metabolism, expression of AtSR1 and AtSR2 is differentially and distinctly regulated by various external signals, and AtSR2 may function in the regulation of sucrose synthase by specific phosphorylation.

Amino Acid Sequence↗

PubMed2001

Continuous regional arterial infusion (CRAI) therapy reduces the mortality rate of acute necrotizing pancreatitis: results of a cooperative survey in Japan.

We evaluated the usefulness of continuous regional arterial infusion (CRAI) of protease inhibitors and antibiotics in 156 patients with acute necrotizing pancreatitis (ANP) collected in a cooperative survey carried out in 1997 in Japan. The overall mortality rate was 18.6%, and the frequency of infected pancreatic necrosis was 12.8%. There was no significant difference in mortality rates between patients who received the protease inhibitor via CRAI and the antibiotics intravenously (group A) and patients who received both the protease inhibitor and the antibiotics via CRAI (group B), but the frequency of infected pancreatic necrosis was significantly lower in group B (7.6%) than in group A (23.5%). The mortality rate in patients in whom CRAI therapy was initiated within 48 h after the onset of ANP (11.9%) was significantly lower than that in patients in whom CRAI therapy was initiated more than 48 h after the onset (23.6%). These results suggested that CRAI of both protease inhibitors and antibiotics was effective in reducing mortality and preventing the development of pancreatic infection in ANP when initiated within 48 h after the onset of ANP.

Adult↗

PubMed2001

Genetic mutations in exons 3 and 4 of the pancreatic secretory trypsin inhibitor in patients with pancreatitis.

PURPOSE: We hypothesized that mutations in the pancreatic secretory trypsin inhibitor (PSTI) gene could promote autodigestion, leading to acute or chronic pancreatitis. Our investigation involved mutation analysis of the PSTI gene in patients with acute or chronic pancreatitis. METHODS: Mutation analysis for the PSTI gene was performed in patients with acute or chronic pancreatitis. Unrelated healthy volunteers and family members of a chronic pancreatitis patient with point mutations in the PSTI gene were also analyzed. RESULTS: Two types of single-point mutation in the PSTI gene were observed in one patient with chronic pancreatitis: 34Asn (AAT)-to-Ser (AGT) (101 A > G N34S: N34S) in exon 3, and 67Arg (CGC)-to-Cys (TGC) (199 C > T R67C: R67C) in exon 4. No mutations with amino-acid substitution were found in other patients or in the volunteer group. In the patient with the PSTI gene mutations, no additional mutations were observed in the cationic trypsinogen gene. The family study revealed that the mother and a maternal uncle were homozygotes for the N34S mutation, while the father and brother were compound heterozygotes for the N34S and R67C mutations. The uncle (N34S/N34S) showed clinical manifestations of pancreatitis, but the other family members did not. CONCLUSIONS: The N34S mutation may cause a predisposition to pancreatitis, with incomplete penetrance. However, with the limited information available, it is not known whether the R67C mutation promotes pancreatitis.

Adolescent↗

PubMed2001

Living-related partial liver transplantation for decompensated hepatitis B without reactivation of hepatitis B in the following 30 months.

We report a case of living-related partial liver transplantation for decompensated hepatitis B without reactivation of hepatitis B in the following 30 months, and we analyze the factors that indicate a favorable prognosis for transplantation. The 42-year-old female patient received continuously administered lamivudine before transplantation, and hepatitis B virus immunoglobulin (HBIG) from the anhepatic phase to the present. Currently, she shows a normal aminotransferase level and is negative for hepatitis B surface antigen and hepatitis B virus (HBV) DNA by polymerase chain reaction amplification. Sequence analysis was performed. The entire precore/core region and part of the polymerase region of HBV were sequenced by a direct sequencing method after polymerase chain reaction. No specific mutation was found in these regions. These observations show that the key factors in the long-term successful treatment of this patient appear to be the combination therapy of lamivudine and HBIG that the patient received from around the time of the transplantation. Furthermore, the lack of specific mutations, including lamivudine resistant-mutations, is likely to represent an additional factor in the effectiveness of this treatment.

Adult↗

PubMed2001

Gastric and intestinal phenotypes of gastric carcinoma with reference to expression of brain (fetal)-type glycogen phosphorylase.

PURPOSE: Although reports have suggested that differentiated gastric carcinomas have different phenotypes, i.e., gastric and intestinal type, this classification is complicated and can be confusing. Our previous studies have demonstrated a close relationship between carcinogenesis in differentiated-type gastric cancer and the expression of brain (fetal)-type glycogen phosphorylase (BGP). The purpose of this study was to investigate the relationship between the mucin phenotype of gastric carcinoma and BGP expression. METHODS: Ninety-six specimens of gastric carcinoma were studied using specific anti-BGP antibody. Correlation of BGP expression with intestinal and gastric phenotypes was determined with the anti-mucin antibodies, HGM, CD10, and MUC2. RESULTS: BGP was expressed in 82.6% (38/46) of differentiated type and in 24.0% (12/50) of undifferentiated type carcinomas. The incidence of BGP positivity was significantly greater in the differentiated-type carcinoma than in the undifferentiated type (P < 0.001). The proportions of gastric, mixed and intestinal types in differentiated and undifferentiated gastric carcinomas were 13.0%, 47.8%, and 39.2%, and 56.0%, 32.0%, and 12.0%, respectively. In both differentiated and undifferentiated types, the phenotype of gastric and intestinal mucin expression corresponded very well with BGP expression, that is, more than 90% of carcinomas with gastric type did not express BGP, whereas approximately 90% of carcinomas with intestinal type did express BGP. CONCLUSIONS: The classification of gastric and intestinal phenotypes of gastric carcinoma in terms of BGP expression was simpler and clearer than such classification in terms of mucin immunohistochemistry. It is suggested that BGP is a useful biomarker for the classification of intestinal and gastric type carcinoma of the human stomach, including classification from the carcinogenetic point of view.

Carcinoma↗

PubMed2001

A new procedure of percutaneous microwave coagulation therapy under artificial hydrothorax for patients with liver tumors in the hepatic dome.

Percutaneous microwave coagulation therapy (PMCT) has been widely used as an effective minimal invasive therapy for small liver tumors. The occurrence of a sonographic masked space due to the presence of the lung, however, has become a major obstacle to visualizing the whole tumor in the hepatic dome. To facilitate the use of PMCT for liver tumors in the hepatic dome, we developed PMCT in combination with the artificial hydrothorax method (percutaneous transdiaphragmatic MCT: PTD-MCT). Our new approach for PMCT to the hepatic tumors located in Couinaud's segments VIII or VII just under the diaphragm resulted in a successful treatment. The separation of the lung from the diaphragm by the infusion of saline into the pleural cavity enabled us not only to visualize the whole tumor in the hepatic dome to accurately target the tumor, but also helped us to avoid injuring the lung. PTD-MCT is therefore strongly recommended for the treatment of liver tumors in the hepatic dome.

Aged↗

PubMed2001

Effect of sesamin on mitochondrial and peroxisomal beta-oxidation of arachidonic and eicosapentaenoic acids in rat liver.

The effects of dietary sesamin on the hepatic metabolism of arachidonic (AA) and eicosapentaenoic (EPA) acids, were investigated with respect to their beta-oxidation and secretion as triacylglycerol (TG). For 2 wk, rats were fed three types of dietary oils: (i) corn oil (control) group; (ii) EPA group: EPA ethyl esters/rapeseed oil = 2:3; (iii) AA group: AA ethyl esters/palm oil/perilla oil = 2:2:1, with or without 0.5% (w/w) of sesamin. Dietary sesamin significantly increased the activities of hepatic mitochondrial and peroxisomal fatty acid oxidation enzymes (mitochondrial carnitine acyltransferase I, acyl-CoA dehydrogenase, and peroxisomal acyl-CoA oxidase). Dietary EPA increased mitochondrial carnitine acyltransferase I and peroxisomal acyl-CoA oxidase. Dietary AA, however, had an effect on peroxisomal acyl-CoA oxidase only. In whole liver and the TG fraction, EPA and AA concentrations were significantly increased by dietary EPA and AA, respectively, and were decreased by dietary sesamin. In hepatic mitochondria and peroxisomes, EPA concentration was increased by dietary EPA, but AA was not changed by dietary AA. The addition of dietary sesamin to the EPA-supplemented diet significantly decreased the EPA concentration compared to concentrations found with consumption of dietary EPA alone. These results suggest that sesamin increased beta-oxidation enzyme activities and reduced hepatic EPA and AA concentrations by degradation. The stimulating effect of sesamin on beta-oxidation, however, was more significant in the EPA group than in the AA group. Hepatic AA concentration was altered by the joint effect of sesamin through esterification into TG and the stimulation of beta-oxidation.

Animals↗

PubMed2001

Effect of reactive oxygen species on fetal lung maturation.

OBJECTIVES: Fetal lung maturation in preterm infants with chorioamnionitis is known to be accelerated. However, the molecular basis of this pathological acceleration has not been elucidated. We investigated whether reactive oxygen species play a role in the acceleration of fetal lung maturation. STUDY DESIGN: On the 16th day of gestation, xanthine (1mM) and xanthine oxidase solution (0.1-100mU/ml) were injected into the intrauterine cavity of pregnant rats. On the 19th day of gestation, we examined the expression of the mRNA of surfactant associated proteins A, B and C (sp-A, sp-B and sp-C) by reverse transcription-polymerase chain reaction. RESULTS: sp-A, sp-B and sp-C mRNAs were observed in lung tissue from fetal rats stimulated by xanthine-xanthine oxidase in contrast to the control. CONCLUSION: Reactive oxygen species in amniotic fluid might be an important factor in accelerated fetal lung maturation associated with chorioamnionitis in the rat experimental model.

Animals↗