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Biomedical subjects

T Murata

Publications and source records attributed to T Murata.

At least 109 records · Page 6Linked to original sources
PubMed2001

Suppression of experimental membranous glomerulonephritis in rats by an anti-MHC class II antibody.

BACKGROUND: We previously reported that idiopathic membranous nephropathy (IMN) strongly correlated with HLA-DRB1*1501-DRB5*0101-DQAI*0102-DQB1* 0602, a specific haplotype of human major histocompatibility complex (MHC), in Japanese patients. To investigate the role of MHC in the development of rat Heymann nephritis (HN), an animal model of membranous nephropathy, a monoclonal antibody (mAb) specific to rat MHC class II antigen (RT1B) was administered, and its effectiveness in inhibiting HN was assessed. METHODS: Active HN was induced in HN-sensitive Lewis rats by administering brush border proteins of rat proximal uriniferous tubules (FX1A). Rats were divided into four groups: rats treated with 1,000 micorg anti-rat MHC class II mAb, rats treated with 100 microg anti-rat MHC class II mAb, rats treated with murine myeloma IgG, and rats that did not receive either FX1A or any other mAb. We examined the differences in 24-hour urinary protein excretion and serum alloantibody titers against FX1A between groups at different time intervals, and the histologic features of kidneys at the end of the study. RESULTS: HN was induced in Lewis rats by inoculation with FX1A antigen. Administration of anti-MHC class II mAb successfully lowered urinary proteins, production of anti-FX1A alloantibodies, and the development of glomerular lesions in a dose-dependent manner. CONCLUSION: The present results demonstrated that the MHC class II molecule itself is directly involved in the pathogenesis of HN, and suggest that this therapy would be any better (or less toxic) than nonselective immunosuppressants in the treatment of IMN.

Animals↗
PubMed2001

Greater resistance and lower contribution of free radicals to hypoxic neurotoxicity in immature rat brain compared to adult brain as revealed by dynamic changes in glucose metabolism.

Seven-day-old rat brain slices were incubated at 36C in oxygenated Krebs-Ringer solution containing [(18)F]2-fluoro-2-deoxy-D-glucose ([(18)F]FDG), and serial two-dimensional time-resolved images of [(18)F]FDG uptake by the slices were obtained. The Gjedde-Patlak graphical method was applied to the image data, and the duration limit of hypoxia loading that allowed recovery of the fractional rate constant (k3*) of [(18)F]FDG (proportional to the cerebral glucose metabolic rate) after hypoxia loading to the unloaded control level was 50 min, and MK-801 as an N-methyl-D-aspartate antagonist had neuroprotective effects, but PBN as a free radical scavenger was ineffective. In our previous study in adult (7-week-old) rat brains [Murata et al., Exp Neurol 2000, 164:269-279], the limit of the hypoxia loading time was 20 min, and both MK-801 and PBN were effective. In the immature rat brains, the ratio of aerobic glucose metabolism to the total glucose metabolism was low compared with the adult rat brains, suggesting only a slight involvement of free radicals in hypoxic neurotoxicity. These data suggest that the higher resistance of immature brains to hypoxia compared to that of adult brains is attributable to a lower involvement of free radicals due to a lower aerobic glucose metabolic rate.

Aging↗
PubMed2001

Adenomyomatosis of the papilla of Vater: a case illustrating diagnostic difficulties.

AIMS: To describe the extremely rare case of an adenomyoma of the papilla of Vater. CASE REPORT: A 42-year-old woman was hospitalized for epigastralgia and high fever. The clinical presentation and endoscopic, biochemical, and radiologic findings led to the diagnostic impression of a dysfunction of the papilla of Vater. The patient was treated successfully by laparotomy and duodenotomy, incorporating cholangiomanometry and cholangiography. Intraoperative frozen-section examination of a transduodenal papillectomy specimen led to the diagnosis of adenomyomatosis of the papilla. The patient is doing well 38 months postoperatively. CONCLUSION: Such a combined approach to intraoperative diagnosis was important to avoid excessive surgery for a benign periampullary disease.

Abdominal Pain↗
PubMed2001

Simultaneous detection of RNA and protein by in situ hybridization and immunological staining.

Proteinase K is widely used in methods for detection of transcripts in biological specimens by in situ hybridization (ISH). However, treatment with proteinase K hampers detection of RNA and protein simultaneously. We have developed a method for double staining of transcripts and proteins by ISH and IHC staining in imaginal discs and embryos of Drosophila. Instead of treatment with proteinase K, samples are treated with ethanol plus xylene and with acetone. Acetone renders cell membranes permeable to probes and antibodies without damaging tissue integrity, whereas treatment with proteinase K sometimes damages tissues. Treatment of samples with acetone allows hybridization of probe with transcripts in tissue. It is also effective for immunological staining of samples after ISH with a riboprobe. Thus, our method allows detection not only of transcripts but also of specific proteins in relatively intact single samples. (J Histochem Cytochem 49:1177-1182, 2001)

Acetone↗
PubMed2001

Contribution of chloride channel activation to the elevated muscular tone of the pulmonary artery in monocrotaline-induced pulmonary hypertensive rats.

In monocrotaline-treated rat pulmonary artery from which endothelium was removed, greater spontaneous muscular tone was observed under resting conditions than in vehicle-treated artery. The aim of the present study was to show the possible contribution of Cl- channels in the mechanism of the elevated tone. Verapamil almost completely inhibited the elevated spontaneous muscular tone by decreasing [Ca2+]i. The elevated muscular tone was also inhibited by 4,4'-diisothiocyanato-stilbene-2,2'-disulfonic acid (DIDS), a Cl- channel inhibitor. After the inhibition of muscular tone by DIDS, verapamil did not induce further relaxation. Quantitative RT-PCR analysis indicated that the mRNA levels of ClC3 and Ca2+-activated Cl- channels did not change in the pulmonary hypertensive pulmonary artery from those of vehicle-treated rats. These results suggest that the elevated muscular tone observed in the monocrotaline-induced hypertensive pulmonary artery is due to membrane depolarization of smooth muscle cells and that this phenomenon might be mediated by the activation of DIDS-sensitive Cl- channels.

Animals↗
PubMed2001

Isolation and identification of antheridiogens in the ferns, Lygodium microphyllum and Lygodium reticulatum.

Antheridiogens in culture media of 6-week-old prothallia of two species of Schizaeaceous ferns, Lygodium microphyllum and Lygodium reticulatum, were analyzed by gas chromatography-mass spectrometry. In both species, the gibberellin A73 methyl ester (GA73-Me) was identified as the most abundant antheridiogen, and the methyl esters of GA9 and of several monohydroxy-GA73 derivatives were also detected. Since both species produced antheridiogens at a high level, they were classified into high-antheridiogen-producing ferns. The response to GA73-Me of gametophytes of both species is also discussed.

Ferns↗
PubMed2001

Purification and characterization of two lectins from a toxic moray, Gymnothrax javanicus.

Two lectins, Gymnothrax javanicus lectin-I (GJL-I) and Gymnothrax javanicus lectin-II (GJL-II) were isolated from the stomach and intestine, and the liver, respectively, of a toxic moray eel, Gymnothrax javanicus. GJL-I is a polymer of two heterogeneous subunits of 67 and 51 kDa. In a hemagglutination inhibition assay, it had sugar-binding specificity toward lactose and lactulose among the mono- or oligo-saccharides and bovine submaxillary mucin (BSM) among the glycoproteins tested. The lectin stimulated nerve growth factor (NGF) synthesis by astroglial cells. GJL-II was a polymer of subunit of 41 kDa. This lectin had N-acetyllactosamine binding specificity.

Amino Acids↗
PubMed2001

Enzymatic synthesis of sulfated disaccharides using beta-D-galactosidase-catalyzed transglycosylation.

We have established a unique enzymatic approach for obtaining sulfated disaccharides using Bacillus circulans beta-D-galactosidase-catalyzed 6-sulfo galactosylation. When 4-methyl umbelliferyl 6-sulfo beta-D-galactopyranoside (S6Gal beta-4MU) was used as a donor, the enzyme induced transfer of 6-sulfo galactosyl residue to GlcNAc acceptor. As a result, the desired compound 6'-sulfo N-acetyllactosamine (S6Gal beta1-4GlcNAc) and its positional isomer 6'-sulfo N-acetylisolactosamine (S6Gal beta1-6GlcNAc) were observed by HPAEC-PAD, in 49% total yield based on the donor added, and in a molar ratio of 1:3.5. With a glucose acceptor, the regioselectivity was substantially changed and S6Gal beta1-2Glc was mainly produced along with beta-(1-1)alpha, beta-(1-3), beta-(1-6) isomers in 74% total yield. When methyl alpha-D-glucopyranoside (Glc alpha-OMe) was an acceptor, the enzyme also formed mainly S6Gal beta1-2Glc alpha-OMe with its beta-(1-6)-linked isomer in 41% total yield based on the donor added. In both cases, it led to the predominant formation of beta-(1-2)-linked disaccharides. In contrast, with the corresponding methyl beta-D-glucopyranoside (Glc beta-OMe) acceptor, S6Gal beta1-3Glc beta-OMe and S6Gal beta1-6Glc beta-OMe were formed in a low total yield of 12%. These results indicate that the regioselectivity and efficiency on the beta-D-galactosidase-mediated transfer reaction significantly depend on the anomeric configuration in the glucosyl acceptors.

Bacillus↗
PubMed2001

Acoustic neuroma with malignant transformation. Case report.

The authors describe the case of a 57-year-old woman who had a right-sided hearing disturbance that had remained untreated for 1 year. The diagnosis was of a right cerebellopontine angle tumor, and the patient underwent its removal via retrosigmoid approach. Pathologically, the tumor was a typical benign neuroma. Growth of residual tumor was detected 4 years after the initial operation, and it was treated with gamma knife surgery (GKS). Six months later, the tumor had grown, and the patient underwent surgery via a combined retrosigmoid-translabyrinthine approach. Abnormal mitotic figures were observed on histological studies, indicating that the tumor had become malignant. Thereafter, the tumor grew rapidly, and the patient died 6.5 years after the initial treatment. It cannot be ruled out that GKS affected the outcome, but the causal sequence was unclear. Because such a patient is rare, documentation of the case was considered clinically important.

Cell Transformation, Neoplastic↗
PubMed2001

[Nitric oxide spares myocardial oxygen consumption through attenuation of contractile response to beta-adrenergic stimulation in patients with idiopathic dilated cardiomyopathy].

BACKGROUND: The results of recent studies suggest that nitric oxide (NO) synthase may increase in the failing myocardium and that NO modulates the myocardial contractile response to beta-adrenergic stimulation. However, there are few data regarding the physiological role of NO in patients with heart failure. The aim of the present study was to address the role of NO in left ventricular contractile response to beta-adrenergic stimulation and corresponding oxygen expenditure in human heart failure. METHODS AND RESULTS: We studied 15 patients with heart failure due to idiopathic dilated cardiomyopathy (mean ejection fraction 0.33). We examined left ventricular contractility (Emax, the slope of end-systolic pressure-volume relation), left ventricular external work (EW), myocardial oxygen consumption (MVO2), and mechanical efficiency (measured as EW/MVO2) with the use of conductance and coronary sinus thermodilution catheters before and during dobutamine (DOB) infusion via a peripheral vein (4.8 +/- 0.3 micrograms.kg-1.min-1 i.v.). Heart rate was kept constant with atrial pacing. We carried out a similar protocol during the intracoronary infusion of the NO synthase inhibitor NG-monomethyl-L-arginine (L-NMMA; 200 mumol). DOB increased Emax, EW, and MVO2 (by 77 +/- 17%, 39 +/- 5%, and 21 +/- 5%, respectively), leading to an increase in mechanical efficiency (25.4 +/- 3.1% to 29.6 +/- 4.1%). L-NMMA alone did not significantly change these variables. Although the concurrent infusion of DOB with L-NMMA increased Emax, EW, and MVO2 (by 140 +/- 21%, 64 +/- 9%, and 35 +/- 5%, respectively) more than DOB alone, mechanical efficiency did not increase further (24.3 +/- 3.3% to 29.5 +/- 4.5%) because EW and MVO2 increased in parallel. CONCLUSIONS: These data suggest that in patients with idiopathic dilated cardiomyopathy, endogenous NO spares MVO2 through attenuation of left ventricular contractile response to beta-adrenergic stimulation while maintaining left ventricular energy-converting efficiency.

Cardiomyopathy, Dilated↗
PubMed2001

Angiopoietin-1 upregulation by vascular endothelial growth factor in human retinal pigment epithelial cells.

PURPOSE: To determine whether vascular endothelial growth factor (VEGF) regulates angiopoietin (Ang)-1 and -2 expression in retinal pigment epithelial (RPE) cells. METHODS: Expression of VEGF, Ang1, and Ang2 in surgically removed human choroidal neovascular membranes (CNVMs) was analyzed by double-label confocal immunofluorescence microscopy. Total RNA was extracted from cultured human RPE cells treated with VEGF for mRNA analysis. Northern blot analysis was performed to examine the time course and dose response of Ang1 and Ang2 mRNA expression. mRNA stability and nuclear run-on analyses were performed. Secreted Ang1 and Ang2 protein levels in conditioned media from RPE cells were examined by Western blot analysis. RESULTS: Ang1 and Ang2 immunostaining colocalized with VEGF-positive stromal cells in human CNVMS: Ang1 and Ang2 mRNAs were expressed by cultured serum-starved RPE cells. VEGF upregulated Ang1 mRNA in a time- and dose-dependent manner without a significant change in Ang2 mRNA. Ang1 and Ang2 mRNAs in RPE cells were as stable as that of S18. VEGF stimulation further increased the half-life of Ang1 mRNA, but did not alter its transcription rate. VEGF increased the amount of Ang1, but not Ang2, protein secreted into the medium. CONCLUSIONS: The colocalization of Ang1 and Ang2 with VEGF in CNVM stromal cells and the upregulation of Ang1 expression by VEGF in cultured RPE cells suggest that VEGF may selectively modulate Ang expression during CNV.

Angiopoietin-1↗
PubMed2001

Periodontitis and serum interleukin-6 levels in the elderly.

The elderly lose teeth as a result of dental caries and periodontitis caused by pathogenic oral bacteria. Periodontitis produces inflammatory cytokines due to the presence of lipopolysaccharides from oral gram-negative bacteria. Although the number of circulating inflammatory cytokines is related to the severity of the periodontitis, it is unclear whether the concentrations also correlate with periodontitis in the elderly. We investigated the relationship between periodontitis status and the concentrations of serum interleukin-6 (IL-6) in the serum from 276 subjects of 70- and 80-year-olds. Of the 276 subjects, 227 (82%) were dentate, 149 (54%) were found to be positive for serum IL-6, and 29 (13%) of the dentate subjects had severe periodontitis. However, there were no significant differences between the severity of periodontitis or the number of teeth and the mean serum IL-6 concentrations. These results provided no evidence to support an association between circulating IL-6 and periodontitis in the elderly.

Aged↗
PubMed2001

[Management strategies for unruptured cerebral aneurysms].

We discussed management strategies for unruptured aneurysms by an analysis of 62 treated and 48 untreated cases. The treated cases were divided into the following two groups; Group A consisted of 38 patients with 46 aneurysms treated during our initial 13 years (7 males, 31 females, 54 +/- 9 years old), and Group B of 24 patients with 32 aneurysms (8 males, females 16, 57 +/- 9 years old) during the last 3 years. In Group A, 36 patients were treated with neck clipping, except for two patients, who had giant aneurysms treated with internal carotid ligation and bypass surgery. All the patients in Group B were treated with either clipping or endovascular coil embolization. Our indications for coil embolization include patients with aneurysms located in paraclinoid internal carotid or basilar arteries, or with multiple aneurysms requiring more than one operation, or with a systemic risky disease for general anesthesia. In group A, 2.6% of cases resulted in death during operation and 10.3% of cases resulted in morbidity, while in group B, there was neither mortality nor morbidity caused by clipping, except for a patient with mild hemiparesis who had been treated with clipping for SAH caused by a procedure of coil embolization. The 50 aneurysms of 48 untreated patients have been observed without any neurosurgical treatment during periods of 6 months to 10 years with a mean of 2 years 7 months. Eventually, four aneurysms resulted in SAH, which cases were treated with emergency clipping or coil embolization. The high rupture rate (3.1% per year) in the natural history may suggest that some aneurysms are more likely to rupture than generally considered. We also reviewed operative findings of all entry clipping cases; more than 80 percent of aneurysms, including those measuring less than 5 mm in diameter, had red colored, thin wall domes with or without bleb. Our conclusion is that surgical indications are for a complementary use of clipping and coil embolization.

Aged↗
PubMed2001

[Beginnings of the study of Western sciences, "Rangaku," in Kyoto and Osaka in close relations with the Edo school].

Beginnings of the study of Western sciences, "Rangaku," in Kyoto and Osaka in the late 18th century are reviewed. Profiles and achievements of several active learners are briefly described; they include Koishi Genzui (Osaka-Kyoto), Tsuji Ranshitsu (Kyoto), Kimura Kenkadō (Osaka), and Hashimoto Sōkichi (Osaka). Genzui, after having successfully made good relations with Sugita Genpaku and Ohtsuki Gentaku, leading masters of the Edo school, played a role of an advocator for promoting "Rangaku" in Osaka and Kyoto. As a result, Kenkadō attained the publication of his book "Ikkaku Sankō," a monograph of the Western crude drug unicorn, with the help of Gentaku, who had translated a Dutch reference into Japanese for him. Ranshitsu and Sōkichi were taught the Dutch language by Gentaku; Sōkichi is known as the founder of "Rangaku" in Osaka.

History, 18th Century↗
PubMed2000

Effect of food deprivation and leptin repletion on the plasma levels of estrogen (E2) and NADPH-d reactivity in the ventromedial and arcuate nuclei of the hypothalamus in the female rats.

The exact role of leptin in fasting has not been completely elucidated. To determine whether leptin can act in fasting to influence plasma estrogen levels and nitric oxide synthase reactivity in food regulating centers of the brain, we fasted female rats for 4 days and treated them i.p. with vehicle or 100 microg of recombinant mouse leptin as 1 ml on the 3rd and 4th day twice daily (10.00 and 17.00 h). Proestrus blood was collected at 10.00, 14.00, 18.00 and at 22.00 h, plasma obtained and assayed for estrogen (E2) and leptin levels. Verification of ovulation occurrence was by examining the oviduct for extruded ovum. The rat brains were removed and processed for nitric oxide synthase reactivity in the ventromedial hypothalamus (VMH) and arcuate nucleus (ARC) using NADPH-diaphorase histochemistry, a marker for neurons expressing NOS enzyme. Leptin effect on dependable variables such as food intake, water intake and body weight gain was also investigated. Four days fasting significantly decreased body weight, estrogen and postfast leptin levels, nitric oxide reactivity in the VMH and ARC nucleus and stopped ovulation in many (4 out of 5) rats fasted and given vehicle. Leptin treatment significantly increased plasma estrogen and postfast leptin levels, restored ovulation in many (4 out of 5) rats and increased nitric oxide reactivity in the VMH and ARC. Leptin significantly inhibited food intake, water intake and gain in body weight during recommenced feeding. These observations suggest that leptin could act in the pituitary-ovarian axis during fasting to improve reproductive function by partly stimulating estrogen secretion.

Animals↗
PubMed2000

Activation of prostacyclin synthesis by mechanical stimulation in the ciliated protozoan Tetrahymena thermophila.

We detected a HPLC peak corresponding to 6-keto-PGF(1alpha), a stable metabolite of prostacyclin (PGI(2)), in [1-(14)C]arachidonate metabolites from the ciliated protozoan Tetrahymena thermophila. Quantitative analysis of 6-keto-PGF(1alpha) by enzyme immunoassay revealed that the synthesis and release were rapidly activated by the mechanical stimulation of a short centrifugation. The activation was suppressed significantly by a cyclooxygenase inhibitor, ibuprofen, and was independent of the extracellular Ca(2+). External addition of PGI(2) and its stable analogue, beraprost, caused a transient increase in the tumbling frequency of swimming. Other prostanoids, PGE(2) and PGF(2alpha), have no effect on the swimming. These results indicate that a free-living ciliate, T. thermophila, synthesizes and has a specific sensitivity to PGI(2).

6-Ketoprostaglandin F1 alpha↗