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Biomedical subjects

H Kaneko

Publications and source records attributed to H Kaneko.

At least 109 records · Page 6Linked to original sources
PubMed2000

Metabolism of furametpyr. 1. Identification of metabolites and in vitro biotransformation in rats and humans.

Urinary and fecal metabolites in male rats treated with a (14)C-labeled fungicide, furametpyr [N-(1,3-dihydro-1,1, 3-trimethylisobenzofuran-4-yl)-5-chloro-1, 3-dimethylpyrazole-4-carboxamide, Limber], were purified by a combination of chromatographic techniques, and chemical structures of 14 metabolites were identified by spectroanalyses (NMR and MS). The major biotransformation reactions of furametpyr in rats were found to be (1) N-demethylation, (2) oxidation of the methyl group at C3 of the pyrazole ring, (3) oxidation of the methyl group at C1 of the 1,3-dihydroisobenzofuran ring, (4) hydroxylation at C3 of the 1,3-dihydroisobenzofuran ring, and (5) hydroxylation at C7 of the 1, 3-dihydroisobenzofuran ring. In vitro metabolism by recombinant human cytochrome P450 revealed that a major biotransformation in humans is N-demethylation, catalyzed by CYP1A1, 1A2, 2C19, and 3A4.

Animals↗
PubMed2000

Metabolism of furametpyr. 2. (14)C excretion, (14)C concentrations in tissues, and amounts of metabolites in rats.

14C-Labeled furametpyr [N-(1,3-dihydro-1,1, 3-trimethylisobenzofuran-4-yl)-5-chloro-1, 3-dimethylpyrazole-4-carboxamide, Limber] was dosed to male and female rats at 1 (low dose) and 200 or 300 mg/kg (high dose). Elimination of furametpyr was rapid, and the dosed (14)C was substantially excreted within 7 days (45.5-53.3% in feces, 44.1-53. 8% in urine, and 0.01% in expired air). However, (14)C excretion rate showed sex- and dose-related differences, more rapid in males at low dose. (14)C concentrations in tissues decreased rapidly to generally low levels at 7 days (<0.004 ppm with the low dose and <1. 1 ppm with the high dose). Forty metabolites were detected, and 13 metabolites and 4 glucuronides were identified. A small amount of unchanged furametpyr was detected in feces (0.1-0.5% of the dose). The major metabolites in tissues were N-demethylated metabolites. In a bile study, 52.5-54.2% of the dosed (14)C was rapidly excreted into bile within 2 days. The absorption ratio was estimated to be >93.7% for the low dose (1 mg/kg). Major metabolites in bile were glucuronic acid conjugates of furametpyr hydroxides. On the basis of the results, furametpyr is substantially absorbed from the gastrointestinal tract after oral administration, rapidly distributed to tissues, extensively metabolized, and excreted into urine and bile or feces.

Animals↗
PubMed2000

Comparison between in vivo and in vitro chemokine production in Helicobacter pylori infection.

BACKGROUND: Enhanced gastric mucosal chemokine activity has been demonstrated in patients with Helicobacter pylori infection. However, little is known about the mechanisms involved in this phenomenon. AIM: To examine whether in vivo chemokine activity is similar to in vitro response of gastric epithelial cells infected by H. pylori. PATIENTS AND METHODS: Antral biopsy specimens were obtained from patients with H. pylori infection for organ culture, isolation of H. pylori and histological examination. RESULTS: In organ cultures of mucosal tissues, the levels of interleukin-8 and growth-related gene product a were elevated in patients with peptic ulcer disease compared with those with erosive gastritis or endoscopically normal mucosa. However, there were no significant differences in in vitro cultures of MKN45 or KATO III cells that were infected with H. pylori isolated from these same patients. These in vivo and in vitro alpha-chemokine levels showed no significant association with the presence of cagA gene and CagA protein, ureB genotype, or binding capacity to MKN45 or KATO III cells in individual H. pylori isolates. In contrast, in vivo mucosal alpha-chemokine activity correlated with H. pylori colonization density. CONCLUSION: Mucosal chemokine profiles and inflammatory responses in H. pylori infection may be associated more closely with host factors, including those determining bacterial adhesiveness, than with differences in H. pylori strains.

Antigens, Bacterial↗
PubMed2000

Interleukin 6 receptor expression by human cord blood- or peripheral blood-derived primitive haematopoietic progenitors implies acquisition of different functional properties.

The significance of interleukin 6 receptor (IL-6R) expression by cord blood (CB)- and peripheral blood (PB)-derived primitive haematopoietic progenitors was investigated. IL-6R was preferentially expressed by PB-derived myeloid progenitors. Most PB-derived erythroid bursts (BFU-E) and mixed colony-forming cells (CFU-Mix) did not express this receptor. However, CB-derived primitive progenitor cells possessed multipotentiality, irrespective of IL-6R expression. Interestingly, the long-term culture-initiating cell (LTC-IC) population was enriched in PB-derived CD34+ IL-6R+ cells, but the extended LTC-IC (ELTC-IC) population, which represents a less mature class of haematopoietic progenitors, seemed to be equally distributed in the IL-6R+ and IL-6R- cell populations. In contrast, the number of LTC-ICs and ELTC-ICs was similar in CB-derived CD34+ IL-6R+ or IL-6R- cells. It is noteworthy that the number of LTC-ICs and ELTC-ICs in CB-derived CD34+ cells was markedly higher than that in PB-derived CD34+ cells regardless of IL-6R expression. Telomerase activity was consistently lower in PB-derived CD34+ IL-6R- cells than in CD34+ IL-6R+ cells. In contrast, telomerase activity was similar in CB-derived CD34+ IL-6R+ or IL-6R- cells. The pattern of telomerase induction upon cytokine stimulation differed between CB- and PB-derived CD34+ IL-6R+ or IL-6R- cells. However, overall telomerase activity per dish was well correlated with the proliferative potential of both cell populations, suggesting that induction of telomerase plays an important role in the escape from replicative senescence of primitive haematopoietic progenitors. Collectively, these results suggest that CB-derived primitive progenitors are less mature than PB-derived progenitors and that the expression of IL-6R by primitive haematopoietic progenitors may have different implications for PB- and CB-derived CD34+ cells.

Antigens, CD↗
PubMed2000

Reduced IFNgamma production in response to IL-12 stimulation and/or reduced IL-12 production in atopic patients.

BACKGROUND: Several studies have shown that interleukin (IL)-4 and interferon-gamma (IFNgamma) are important for the regulation of IgE production and that IL-12 induces IFNgamma. OBJECTIVE: IFNgamma production in response to IL-12 stimulation and IL-12 production were investigated in peripheral blood mononuclear cells (PBMCs) of atopic patients with various levels of serum IgE. METHODS: Cytokine production from PBMCs was measured following stimulation with a nonspecific stimulator (phytohemagglutinin: PHA), a specific stimulator (Der f 1) and IL-12 in 17 healthy controls and 23 atopic patients with various serum IgE levels. RESULTS: The IFNgamma production by IL-12-stimulated PBMCs in the atopic group was lower than that in the control group. Furthermore, the serum IgE level was negatively correlated with IFNgamma production by PBMCs stimulated with IL-12 (P < 0.001), and with IL-12 production by PBMCs stimulated with Der f 1 (P < 0.001). Although the IFNgamma concentrations by PHA-stimulated PBMCs were correlated with those by IL-12-stimulated PBMCs, there were differences in several patients. CONCLUSIONS: Our results indicated that atopic patients may have some abnormality in the IL-12-IFNgamma loop. It was shown that the elevation in IgE levels in atopic patients may be due to reduced IFNgamma production in response to IL-12 stimulation and/or due to reduced IL-12 production.

Adolescent↗
PubMed2000

Plasma platelet-activating factor acetylhydrolase deficiency is associated with atherosclerotic occlusive disease in japan.

PURPOSE: Plasma platelet-activating factor acetylhydrolase (PAF-AH) is known to catalyze platelet-activating factor, thereby inactivating its inflammatory function. Deficiency of this enzyme is caused by a missense (G(994)-->T) in exon 9 of the plasma PAF-AH gene. In this study, we investigated a possible association of this mutation with the risk of atherosclerotic occlusive disease (AO) in Japanese patients. METHODS: We studied 104 patients with AO. The control group consisted of 114 subjects matched for age and sex. Plasma PAF-AH activity was measured in the patients with AO. RESULTS: The prevalence of the mutant genotype (GT + TT ) was significantly more frequent in patients with AO than in control subjects (36.5% vs 23.7%; P <.05). Among the patients with AO, those with the mutant allele had significantly more risk factors of prior stroke or ischemic heart disease than patients with normal genotypes. Plasma PAF-AH activity was higher in patients with AO than in control subjects in normal genotype subgroups. CONCLUSIONS: The missense (G(994)-->T) in exon 9 of the plasma PAF-AH gene is associated with AO in Japanese people.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed2000

Gastric metaplasia in the duodenal bulb shows increased mucosal interleukin-8 activity in Helicobacter pylori-positive duodenal ulcer patients.

BACKGROUND: Although increased levels of interleukin (IL)-8 are known to be associated with infiltration of neutrophils in the gastric mucosa with Helicobacter pylori infection, no study has investigated the relationship between local IL-8 levels and neutrophil infiltration in the duodenal mucosa of patients with duodenal ulcer (DU). METHODS: Duodenal mucosal biopsy specimens with and without gastric metaplasia (GM) were obtained from patients with DU and controls with an endoscopic methylene blue (MB) staining method. Levels of IL-8 secreted in the organ cultures of biopsy specimens were measured with an enzyme-linked immunosorbent assay. The number of myeloperoxidase-positive neutrophils infiltrating the lamina propria was determined in immunohistochemically stained tissue sections. RESULTS: Histologic assessment showed that there was a strong correlation between the absence of endoscopic MB staining and the extent of GM. The levels of IL-8 in both duodenal and antral mucosal tissues were significantly higher in patients with H. pylori infection than in those without infection. In patients with DU the duodenal mucosal tissues with GM (MB-unstained mucosa) showed significantly higher levels of IL-8 than those without GM (MB-stained mucosa) or the antral mucosa. The number of neutrophils showed similar variations among DU and control patients with a positive correlation with IL-8 activity. The levels of IL-8 and the number of neutrophils decreased after H. pylori eradication in both duodenal and antral mucosal tissues, and these changes were more remarkable in the duodenal mucosal tissues with GM. CONCLUSIONS: Increased IL-8 activity in the duodenal mucosa with GM may be important for ulcerogenesis in H. pylori-positive DU patients.

Adult↗
PubMed2000

Metabolism of Cyanox in rat. II. Sex-related differences in oxidative dearylation and desulphuration.

1. To examine the metabolites of Cyanox (O-4-cyanophenyl O,O-dimethyl phosphorothioate, cyanophos, CYAP) in brain, liver, blood cells and plasma during the early toxic period, the male and female rat was administered a single oral dose of [phenyl-14C]Cyanox at dose levels of 50 mg/kg and killed 5, 10 and 20 min thereafter. 2. Sex-related differences in the concentrations of metabolites were observed. Cyanoxon, produced by oxidative desulphuration, was observed in the brains of both sexes at all time points, but the concentrations were 2-6 times higher in the male. The same metabolite was detected in the liver, blood cells and plasma of the male but not the female. The total concentrations of oxidative dearylation metabolites (4-cyanophenol + 4-cyanophenylsulphate + glucuronide of 4-cyanophenol) in plasma, blood cell, brain and liver were larger in the male at all time points than those in the female, whereas the reverse was the case for demethylated metabolites (desmethylcyanox + desmethylcyanoxon) in all tissues except for the brain. 3. Studies of the in vitro metabolism of Cyanox revealed no sex-related difference for hepatic cytosolic fractions in terms of the major in vitro metabolic reaction, demethylation. On the other hand, the major reactions in microsomal fractions, oxidative desulphuration and oxidative dearylation, were significantly (2-3 times) greater in the male than in the female. 4. Oxidative desulphuration and oxidative dearylation, involving cytochrome P450 enzymes, were inhibited by male-specific rat CYP2C11 antiserum. The degree of inhibition was more pronounced in the male case. Thus, the results strongly suggest that the 2C family of cytochrome P450 (male, CYP2C11 and CYP2C13; female, CYP2C12) contributes to oxidative desulphuration and dearylation of cyanox in the rat and that the activity of male-specific CYP2C11 (and CYP2C13) is greater than that of female-specific CYP2C12. The consequent greater formation of cyanoxon in the male is consistent with the higher toxicity in this sex.

Administration, Oral↗
PubMed2000

Differential scanning calorimetry study on the inner membrane lipids prepared from barotolerant Pseudomonas sp. BT1.

We investigated the properties of membrane lipids of barotolerant Pseudomonas sp. BT1 by differential scanning calorimetry and spectrophotometry using a system equipped with a hydrostatic pressure controller. In the case of cells grown under high pressure, an endothermic peak appeared under high-pressure measurement conditions. However, in the case of cells grown at 0.1 MPa, such a peak was not observed. It was also observed on spectrophotometry that the membrane lipids from cells grown at 30 MPa had stable properties in comparison with those grown at 0.1 MPa various hydrostatic pressures and temperatures.

Calorimetry, Differential Scanning↗
PubMed2000

Lack of significant estrogenic or antiestrogenic activity of pyrethroid insecticides in three in vitro assays based on classic estrogen receptor alpha-mediated mechanisms.

Estrogenic and antiestrogenic activity of pyrethroid insecticides (d-trans-allethrin, cypermethrin, empenthrin, fenvalerate, imiprothrin, permethrin, d-phenothrin and prallethrin) was evaluated using a suite of three in vitro assays based on classic human estrogen receptor alpha (hER alpha)-mediated mechanisms. A mammalian cell-based luciferase reporter gene assay was developed for examining effects on hER alpha-mediated gene activation. hER alpha-independent effects on the gene activation were examined using control cells with constitutive luciferase activation by a herpes simplex virus thymidine kinase (HSV-TK) promoter for determining appropriate dose levels of test chemicals. Moreover, the test chemical-dependent interaction between hER alpha and a coactivator (transcriptional intermediary factor 2: TIF2) was analyzed by a yeast two-hybrid method, competitive binding to hER alpha being assayed by a fluorescence polarization method. Significant (p < 0.05) positive effects of estrogenic substances (E2/estradiol, diethylstilbestrol, and p-nonylphenol) were detected in all assays. An antiestrogen, 4-hydroxytamoxifen, significantly inhibited E2-mediated transactivation and interaction between hER alpha and TIF2 through hER alpha binding (p < 0.05). However, none of the pyrethroids tested showed significant (p < 0.05) estrogenic or antiestrogenic effects (100 nM-10 microM), indicating that they do not impact on the classic hER alpha-mediated activation pathway in vitro.

Binding, Competitive↗
PubMed2000

Maturation/M-phase promoting factor: a regulator of aging in porcine oocytes.

Deterioration in the quality of mammalian oocytes during the metaphase-II arrest period is well known as "oocyte aging." Oocytes in which aging has occurred are called aged oocytes, and these oocytes show enhanced activation and higher fragmentation rates after parthenogenetic activation. Previously we showed that porcine aged oocytes had low maturation/M-phase promoting factor (MPF) activity, and we suggested that this low MPF activity contributed at least in part to the aging phenomena. In the present study, we examined the relationship between MPF activity and these aging phenomena by artificially regulating MPF activity in porcine metaphase-II-arrested oocytes. Since we have shown recently that aged porcine oocytes contain abundant phosphorylated inactive MPF, so-called pre-MPF, we used vanadate and caffeine, which affect the phosphorylation status of MPF, to regulate MPF activity. Incubation of 48-h-matured oocytes with vanadate for 1 h increased the phosphorylation of MPF and decreased MPF activity. The parthenogenetic activation and fragmentation rates were significantly increased compared with those of control oocytes. Conversely, treatment of 72-h-cultured aged oocytes with caffeine (last 10 h of culture) decreased the level of pre-MPF and elevated MPF activity. These oocytes revealed significantly lower parthenogenetic activation rates and a lower percentage of fragmentation than did untreated aged oocytes. These results indicate that not only the increased ability for parthenogenetic activation but also the increased fragmentation rate observed in porcine aged oocytes may be attributable in part to the gradual decrease in MPF activity during prolonged culture. Control of MPF phosphorylation with these agents may allow for some degree of manipulation of oocyte aging.

Animals↗
PubMed2000

Introduction of raw starch-binding domains into Bacillus subtilis alpha-amylase by fusion with the starch-binding domain of Bacillus cyclomaltodextrin glucanotransferase.

We constructed two types of chimeric enzymes, Ch1 Amy and Ch2 Amy. Ch1 Amy consisted of a catalytic domain of Bacillus subtilis X-23 alpha-amylase (Ba-S) and the raw starch-binding domain (domain E) of Bacillus A2-5a cyclomaltodextrin glucanotransferase (A2-5a CGT). Ch2 Amy consisted of Ba-S and D (function unknown) plus E domains of A2-5a CGT. Ch1 Amy acquired raw starch-binding and -digesting abilities which were not present in the catalytic part (Ba-S). Furthermore, the specific activity of Ch1 Amy was almost identical when enzyme activity was evaluated on a molar basis. Although Ch2 Amy exhibited even higher raw starch-binding and -digesting abilities than Ch1 Amy, the specific activity was lower than that of Ba-S. We did not detect any differences in other enzymatic characteristics (amylolytic pattern, transglycosylation ability, effects of pH, and temperature on stability and activity) among Ba-S, Ch1 Amy, and Ch2 Amy.

Amino Acid Sequence↗
PubMed2000

Helicobacter pylori-associated gastric ulcer exhibits enhanced mucosal chemokine activity at the ulcer site.

BACKGROUND AND AIM: Although mucosal alpha- and beta-chemokines are considered to be involved in the pathogenesis of Helicobacter pylori-associated gastritis, little is known how these chemokines are related to the ulcerogenesis in peptic ulcer patients. We examined the levels of interleukin (IL)-8 and macrophage inflammatory protein-1alpha (MIP-1alpha) in organ cultures and the numbers of inflammatory cells infiltrating the lamina propria by using the mucosal tissues obtained from gastric ulcer (GU) patients with and without H. pylori infection. METHODS: Levels of IL-8 and MIP-1alpha secreted in organ cultures were measured by an enzyme-linked immunosorbent assay. Numbers of myeloperoxidase-positive neutrophils, CD68-positive macrophages, and mononuclear cells were determined in tissue sections. RESULTS: The mucosal tissues of both the gastric antrum and the ulcer site obtained from patients with H. pylori-positive GU showed significantly higher levels of IL-8 and MIP-1alpha and increased numbers of inflammatory cells compared with the corresponding mucosal tissues from those with H. pylori-negative GU or the antral mucosal tissues from H. pylori-negative controls. When the values were compared between the mucosal tissues from the gastric antrum and those from the ulcer site, the latter group of tissues showed significantly higher levels of IL-8 and MIP-1alpha and increased numbers of neutrophils and macrophages than the former group regardless of its healing process in patients with H. pylori-positive GU. CONCLUSION: Mucosal alpha- and beta-chemokines may be important to the ulcerogenesis in H. pylori-associated GU disease.

Adult↗
PubMed2000

Protective effect of human urinary thrombomodulin on ischemia- reperfusion injury in the canine liver.

This study was performed to determine whether human urinary soluble thrombomodulin plays a role in liver ischemia-reperfusion injury. Liver ischemia was induced in two groups of dogs. Group 1 was exposed to 60 min ischemia, and group 2 was exposed to 60 min ischemia after preischemic administration of human urinary soluble thrombomodulin. In group 1, the thrombin-antithrombin complex and hyaluronic acid were significantly elevated after ischemia, compared with the preischemic values. While liver issue blood flow and the plasmin-alpha(2)-plasmin inhibitor complex significantly decreased, AST, ALT and m-AST dramatically increased after reperfusion. In group 2, the increase in the thrombin-antithrombin complex and hyaluronic acid was significantly suppressed, and AST, ALT and liver tissue blood flow significantly improved, compared with group 1. Histologically, in group 2, the hepatic tissue structure, including endothelial cells, was relatively intact. These findings suggest that administration of thrombomodulin inhibits endothelial cell injury and coagulopathy and offers protection from liver ischemia-reperfusion injury.

Animals↗
PubMed2000

Long-term study of a female hyper-IgM immunodeficiency.

Hyper-IgM immunodeficiency (HIM) is an immunological disorder characterized by normal or elevated serum IgM levels, and reduced serum IgG and IgA levels, due to the disruption of immunoglobulin class switching in B cells. X-linked hyper-IgM is caused by the defective expression of the CD40 ligand on activated T cells, which induces immunoglobulin class switching along with some cytokines, such as interleukin 4, by the signal transduction of CD40 in B cells. We report on a Japanese girl who initially showed low serum IgM, IgG and IgA levels like patients with common variable immunodeficiency; however, in the course of time, serum IgG levels became reduced and serum IgM levels increased, resulting in the typical immunoglobulin profile of HIM. Neutropenia, one of the features of X-linked HIM, was not observed. In spite of extremely low serum IgG levels, she did not show any predisposition to severe infection, even without gammaglobulin replacement therapy. No mutation of the CD40 ligand or CD40 was detected. Sequencing of the complementarity-determining region of immunoglobulin heavy-chain genes in peripheral B lymphocytes revealed that they were all in frame, and insertion of the N region was detected. These results indicate that the heavy-chain gene rearrangement in the patient's B cells is intact. Non-X-linked HIM has heterogeneous pathogenetic mechanisms, and some groups may show the resistance to infection at the healthy donor level. The underlying defects in non-X-linked HIM might be specifically involved in class switching.

Adolescent↗
PubMed2000

Effect of intravenous cyclophosphamide in systemic lupus erythematosus: relation to lymphocyte subsets and activation markers.

Since the mechanism mediating the beneficial effect of intravenous cyclophosphamide (IVCY) in systemic lupus erythematosus (SLE) is unknown, we investigated lymphocyte subsets and markers of activated lymphocytes in patients received IVCY, and compared the results with the effect of steroid pulse. In 55 patients with SLE, 34 patients receiving IVCY [21 cases (61.8%) were responsive] and 25 patients received steroid pulse [21 cases (84.0%) were responsive] (four patients who were resistant to steroid pulse therapy were transferred to IVCY). When the lymphocyte subsets and markers of activated lymphocytes were compared in the responsive and unresponsive group of IVCY, soluble CD4 levels and the ratio of HLA-DP-positive T cells were significantly higher in the unresponsive group. Further, the changes of these markers and costimulatory molecules [LFA-1 (CD11a), ICAM-1 (CD54), CD40 and CD40-ligand (CD154)] were also examined in the responsive patients. The ratio of HLA-DP-positive T cells did not change in the IVCY-responsive group, while it decreased in the steroid pulse therapy-responsive group. The ratio of CD11a on T cells increased and CD54 on B cells decreased in the IVCY-responsive group. The ratio of CD154 on T cells increased in the steroid pulse-responsive group, while it decreased in the IVCY-responsive group. These results suggest that the effect of IVCY is different to that of steroid pulse therapy and mainly related to B cell activation, and that these markers may contribute to predict the responsiveness of IVCY.

Adult↗