Search PubMed⌕ Search

Biomedical subjects

H Murata

Publications and source records attributed to H Murata.

At least 181 records · Page 10Linked to original sources
PubMed1995

Use of the derivatizing agent 4-aminobenzoic acid 2-(diethylamino)ethyl ester for high-sensitivity detection of oligosaccharides by electrospray ionization mass spectrometry.

A method for the high-sensitivity detection of oligosaccharides by electrospray ionization mass spectrometry (ESI-MS) is reported. The method involves the chemical derivatization with 4-aminobenzoic acid 2-(diethylamino)-ethyl ester (ABDEAE). This derivative, which contains a 2-(diethylamino)ethyl group, having a high proton affinity, enhances the ionization efficiency of analytes in the positive ESI mode. Experiments using maltohexaose as a model oligosaccharide revealed that derivatization with ABDEAE gave a remarkably large increase in molecular ion abundance. Using a mixture of acetonitrile, 2-methoxyethanol, 2-propanol, and water (1:1:1:1 v/v/v/v) as solvent for ESI, ABDEAE-derivatized maltohexaose could be detected at a level of 10 fmol. This represents a 5000-fold improvement in sensitivity over underivatized maltohexaose. ESI tandem mass spectrometry of the ABDEAE-derivatized maltohexaose provides structural information at the low-picomole level. In this spectrum, 1,5X' and 0,2A" series of sequence ions, arising from ring cleavage, were observed as the predominant ions.

Anions↗
PubMed1995

Limited TCR repertoire of infiltrating T cells in the kidneys of Sjögren's syndrome patients with interstitial nephritis.

To analyze the mechanism of interstitial nephritis in patients with Sjörgren's syndrome (SS), we examined the TCR repertoire of infiltration T cells in kidney, labial salivary glands, and PBLs using a PCR. The repertoire of the TCR V beta gene on infiltrating T cells from the kidneys of SS patients was more restricted than those on infiltrating T cells in labial salivary glands and PBL. The TCR V beta 2 gene was expressed predominantly in six of seven (86%) SS patients. Junctional sequences of cDNAs encoding the V beta 2 gene on infiltrating T cells in the kidneys of five SS patients showed that some of the cells expanded clonally, indicating Ag-driven stimulation rather than superantigen-induced proliferation. The same V beta 2 clones in the kidney were not detected in labial salivary glands of the same SS patients; the conserved amino acid (arginine at position 96) in the CDR3 region of the V beta 2 gene was found at a frequency of 48.0% in the kidney, whereas it was detected in only 15.4% of the clones in lips. In conclusion, these findings suggest the possibility that T cells that infiltrate the kidneys of SS patients with interstitial nephritis might recognize different autoantigens than those that infiltrate labial salivary glands.

Amino Acid Sequence↗
PubMed1995

Selective reduction of T cells bearing invariant V alpha 24J alpha Q antigen receptor in patients with systemic sclerosis.

A novel subset of T cells characterized by the expression of an invariant T cell antigen receptor (TCR) encoded by V alpha 24J alpha Q gene segments was investigated in patients with systemic sclerosis (SSc). Polymerase chain reaction analysis demonstrated that the V alpha 24 TCR repertoire was selectively used in CD4-CD8- double-negative T cells both in patients and in healthy individuals, while almost all families of TCR V alpha were expressed in single-positive T cell fractions. The V alpha 24+ double-negative T cells were increased by approximately fivefold in patients. However, sequence analysis clearly showed significant differences in the V alpha 24 TCR repertoire dominating in patients and healthy donors. In healthy individuals, the invariant V alpha 24J alpha Q was expanded and comprised 20-50% of the total TCR-alpha, while their selective reduction was observed in SSc patients who also showed expansion of invariant V alpha 24 TCR other than V alpha 24J alpha Q. Analogous to murine invariant V alpha 14J alpha 281 TCR, these results suggest that T cells with invariant V alpha 24J alpha Q TCR would function as regulatory T cells, whereas T cells bearing other invariant V alpha 24 TCR in SSc patients could be autoaggressive T cells in nature.

Asian People↗
PubMed1995

Simultaneous determination of ascorbic acid and dehydroascorbic acid in fish tissues by high-performance liquid chromatography.

An high-performance liquid chromatographic method with post-column derivatization has been developed for the simultaneous determination of ascorbic acid (AA) and dehydroascorbic acid (DHAA) in fish tissues. Extracted AA and DHAA were separated by a Shim-pack SCR-1O1H column within 20 min, reacted with sodium hydroxide containing sodium borohydride and monitored at 300 nm. The detection limits for both AA and DHAA were 0.1 microgram/ml.

Animals↗
PubMed1995

Characterization of a highly toxic, large molecular size heat-stable enterotoxin produced by a clinical isolate of Yersinia enterocolitica.

A novel heat-stable enterotoxin (ST) designated as Y-STc was purified to homogeneity from the culture supernatant of a pathogenic strain of Yersinia enterocolitica serotype O3 and its amino acid sequence was determined. The mature Y-STc was found to consist of 53 amino acid residues, which includes the putative pro-sequence. The molecular weight of Y-STc was 5638 and constituted the largest molecular size in the family of currently known STs. The minimum effective dose of purified Y-STc in the suckling mouse assay was 0.6 ng (0.0 pmol), indicating that, despite the long sequence, Y-STc is the most toxic in the ST family.

Amino Acid Sequence↗
PubMed1995

Initial lithium augmentation improves the antidepressant effects of standard TCA treatment in non-resistant depressed patients.

The hypothesis was tested that an initial lithium-tricyclic antidepressant (TCA) combination has a better antidepressant effect than standard TCA treatment in non-refractory depression at the beginning of an episode. Twenty bipolar melancholic type depressed inpatients under lithium-TCA treatment were compared with 20 patients with the same diagnosis and TCA-placebo treatment for 5 weeks under double-blind conditions. All patients were male. Initial lithium-TCA treatment reduced depressive symptoms significantly more than antidepressant treatment with TCA and placebo after 5 weeks, but not in weeks 1 or 2. It can be concluded that lithium augmentation of TCA treatment should be started even at the beginning of antidepressant TCA treatment to provide a better treatment response in those patients who will profit from long-term lithium prophylaxis, e.g. bipolar patients with melancholic type depression.

Adult↗
PubMed1995

Serum amino acid disturbance in multiple myeloma with hyperammonemia.

From October 1987 to November 1993 we evaluated the serum levels of ammonia and amino acids in 85 patients with multiple myeloma. Six of the 85 cases of multiple myeloma demonstrated hyperammonemia and none of the known causes of hyperammonemia, such as liver failure, could be identified in these patients. All six patients also showed serum amino acid disturbances and conscious disorders in various degrees. In this study we compared these abnormalities in multiple myeloma with those in chronic liver failure (n = 14), the basic diseases of which were liver cirrhosis in six cases and liver cirrhosis complicated hepatocellular carcinoma in eight cases. There was a marked difference in the levels of individual serum amino acids between these two groups. The level of glycine was significantly higher in the multiple myeloma group (P < 0.001); on the other hand, that of tyrosine was significantly higher in the liver failure group (P < 0.005). The histidine (P < 0.005) and arginine (P < 0.005) levels were lower in the myeloma group. The ratio of glycine to tyrosine (Gly/Tyr) was 16.7 +/- 4.85 in the myeloma group and 1.7 +/- 0.12 in the liver failure group. The ratio of glycine to tyrosine was an important criterion for differential diagnosis.

Adult↗
PubMed1995

Properties of highly cross-linked autopolymerizing reline acrylic resins.

Transverse bend strength tests and water sorption and solubility tests were done to compare the properties of highly cross-linked autopolymerizing reline resin with those of conventional non-cross-linked autopolymerizing reline resins. The relationship between composition and properties of autopolymerizing reline resins was also investigated. Highly cross-linked reline resins and the one that contained mainly poly(methyl methacrylate) and methyl methacrylate had a higher transverse bend strength and modulus of elasticity than the other reline resins (p < 0.01). The highly cross-linked reline resins also had significantly lower water sorption than the other reline resins (p < 0.01). Reline resins, except for one, had significantly higher solubility than heat-polymerizing denture base acrylic resins (p < 0.01).

Acrylic Resins↗
PubMed1995

Human dermal fibroblast clones derived from single cells are heterogeneous in the production of mRNAs for alpha 1(I) procollagen and transforming growth factor-beta 1.

Fibroblast clonal heterogeneity has been reported for growth and protein synthesis, but quantitative studies of synthetic phenotype at the pretranslational level have been limited because of difficulty in reliably growing large numbers of clonal cells. We have recently shown a unique stimulatory activity of low oxygen tension in the early phases of clonal growth, which can be used to establish clonal fibroblast cultures suitable for Northern analysis. Using this methodology, we have measured mRNA levels of alpha 1(I) procollagen and transforming growth factor-beta 1 (TGF-beta) both at baseline and after TGF-beta stimulation in a total of 43 clones derived from single cells and from seven different cell strains. We report a remarkable baseline heterogeneity, commonly four- to six-fold, in procollagen mRNA levels among clones and between clones and their parent cultures. Conversely, differences in baseline TGF-beta mRNA levels among clones were either not present or less than onefold. The clonal phenotypic expression of alpha 1(I) procollagen mRNA remained stable after eight additional cell passages. TGF-beta stimulation of itself (autoinduction) was highly variable among clones (range of increases 30% to 150%), and up-regulation of procollagen mRNA levels after TGF-beta stimulation was detected in only 15 (54%) of 28 clonal cultures (range of increases 30% to 353%). A notable lack of correlation was found between baseline mRNA levels of TGF-beta and alpha 1(I) procollagen in clonal cultures. In conclusion, fibroblast clonal populations are remarkably heterogeneous in their baseline procollagen mRNA levels and in their response to TGF-beta.

Adult↗
PubMed1995

Factors influencing gelation time of tissue conditioners.

To investigate the effects of the composition and structure on the gelation of tissue conditioners, we measured gelation time with an oscillating rheometer. Also, the plasticizer factor was determined using linear multiple regression equations with the dependent variable of gelation time and the independent variables of molecular weight, molar volume, solubility parameter and viscosity of plasticizers. The results obtained were (i) gelation time decreased as the average particle size of poly-ethyl-methacrylate was decreased and its weight average molecular weight increased; (ii) gelation time decreased as ethanol content in the liquid increased. It varied depending on the type of plasticizer; (iii) it was suggested that gelation time was explained by linear multiple regression equations with independent variable of molar volume, solubility parameter and viscosity of plasticizer. In particular, the most influential factor was suggested to be molar volume.

Ethanol↗
PubMed1995

Corneal epithelium following penetrating keratoplasty.

AIMS: This study was designed to observe any changes to the corneal epithelium after penetrating keratoplasty. METHODS: The corneal epithelia of 26 patients were observed by specular microscopy 1 week, 1 month, 3 months, and 6 months following penetrating keratoplasty. RESULTS: After re-epithelialisation was confirmed by biomicroscopy 1 week after surgery, specular microscopy revealed many abnormal cells, including spindle shaped cells, nucleated cells, large cells, as well as irregular cell configurations. Although these abnormal findings tended to decrease with time, they were still present in some cases as much as 6 months postoperatively. Computerised morphometric analysis yielded mean cell areas of 1121 (SD 168) microns 2, 1139 (675) microns 2, 1712 (496) microns 2, and 1400 (377) microns 2 at 1 week, 1 month, 3 months, and 6 months respectively, all significantly greater than that of age matched controls (710 (151) microns 2). The shape factor decreased with time, but was still greater than the control level at 6 months. CONCLUSIONS: This study demonstrates that epithelial abnormalities persist longer than expected after penetrating keratoplasty, and that these subtle changes can be detected by specular microscopic observation, potentially allowing for modification and enhancement of the wound healing process.

Adolescent↗
PubMed1995

Enhanced collagen synthesis and transcription by peak E, a contaminant of L-tryptophan preparations associated with the eosinophilia myalgia syndrome epidemic.

The pathogenesis of the eosinophilia myalgia syndrome (EMS) remains unclear. Several abnormal constituents have been found in the L-tryptophan lots responsible for the illness, particularly, 1,1-ethylidenebis[L-tryptophan], also called peak E or EBT, and 3-phenylamino-alanine or peak 5. However, the role of these contaminants in the pathogenesis of EMS and in the development of fibrosis is unknown. We now report that peak E, a dimer of L-tryptophan, is a potent stimulus for human dermal fibroblast DNA and collagen synthesis. Peak E (0.1-1.0 microM) increased DNA synthesis up to four-fold (P = 0.0001) in a dose-dependent manner (r = 0.987). When added to monolayer cultures for 2 to 24 h, peak E (0.5 to 100 microM) caused a progressive, more than threefold increase in alpha 1(I) procollagen mRNA levels and collagenous protein. No increase in procollagen mRNA levels was found after the addition of another major L-tryptophan contaminant, peak 5, or with L-tryptophan itself. Transient transfection with a 2.5-kb alpha 1(I) procollagen promoter-luciferase construct showed that peak E causes a twofold upregulation of promoter activity (P = 0.022). Contraction of collagen gels, consisting of human dermal fibroblasts incorporated into a type I collagen lattice, was enhanced two-fold by exposure to peak E (P = 0.001). We conclude that a major constituent of contaminated batches of L-tryptophan, peak E, is a potent stimulus for fibroblast activation and collagen synthesis. This stimulatory action of peak E may provide a direct mechanism for the development of fibrosis in EMS.

Cells, Cultured↗
PubMed1995

A staining method for bone canaliculi.

The modified Bodian method with protargol (silver protein) is ordinarily used to detect nerve fibers. With this technique, applied to decalcified rat bone sections, the bone canaliculi were clearly stained black with good contrast to the bone matrix in both lamellar and woven bone. In addition, the connections between the bone canaliculi and other canaliculi, osteoblasts, osteoclasts, and chondrocytes were easily detectable. We found that the bone canaliculi of woven bone were fewer in number and ran more irregularly than those of lamellar bone. We believe that this staining method for bone canaliculi in decalcified bone is superior to previously reported methods and may be useful in studies on bone pathology.

Animals↗
PubMed1995

Structural elucidation of aculeximycin. III. Planar structure of aculeximycin, belonging to a new class of macrolide antibiotics.

The planar structure of aculeximycin (1) produced by Streptosporangium albidum has been determined by spectral methods and chemical degradations such as 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU)-methanol reaction, ozonolysis, and periodative oxidation. The antibiotic consists of a 30-membered polyhydroxy lactone ring, an alpha, beta-unsaturated ester group, an intramolecular hemiketal, an oligosaccharide (aculexitriose), a neutral sugar and an amino sugar. The structure of aculeximycin is closely related to those of sporaviridins produced by Streptosporangium viridogriseum. We consider that aculeximycin and sporaviridins belong to a new class of macrolide antibiotics, which is different from the polyol macrolides produced by Streptomyces.

Acetylation↗
PubMed1995

Structural elucidation of aculeximycin. IV. Absolute structure of aculeximycin, belonging to a new class of macrolide antibiotics.

Aculeximycin (1) produced by Streptosporangium albidum possesses a 30-membered polyhydroxy macrocyclic lactone and five sugars including aculexitriose. We have described the determination of the planar structure of N-diacetylated aculeximycin (2) using degradation products, which were obtained by DBU-methanol treatment, ozonolysis and periodative oxidation. In order to determine the relative and absolute configurations of aculeximycin, first, the relative and absolute configurations of the degradation products 10, 11, 12 and 13 were determined. Rychnovsky's method was very useful to determine the relative configurations of these degradation products, and CD exciton chirality and the modified Mosher's methods were applied to determine their absolute configurations. From these results, fourteen out of the twenty asymmetric centers in aculeximycin were determined to be 5S, 17R, 20S, 21R, 23R, 24R, 29S, 30R, 31S, 34R, 35S, 36S and 37R. The absolute configurations at C-14 and C-15 on the hemiketal ring were confirmed using 12 obtained by the partial glycol bond cleavage of 9. Absolute configurations of the remaining asymmetric centers were determined by spectral analysis of 15 and NOE experiment on 1. From these results, the absolute configuration of 1 was determined to be 5S, 7R, 10S, 11R, 14R, 15S, 17R, 19R, 20S, 21R, 23R, 24R, 25S, 29S, 30R, 31S, 34R, 35S, 36S and 37R.

Anti-Bacterial Agents↗
PubMed1995

Relation between parathyroid hormone and cardiac function in long-term hemodialysis patients.

Radionuclide ventriculographic and echocardiographic assessments of left ventricular cardiac function were studied in 46 long-term maintenance hemodialysis patients, and comparison of cardiac function pre- and post-parathyroidectomy in 10 hemodialysis patients with secondary hyperparathyroidism was investigated. In long-term hemodialysis patients, impairment of cardiac function was observed in 80.4%. In an overall study of 46 patients, no correlation between intact parathyroid hormone (iPTH) level and left ventricular ejection fraction (LVEF) was observed, but a significant (p < 0.05) negative correlation was observed in patients with an iPTh blood level over 200 pg/ml. A negative correlation between fractional fiber shortening and an iPTh level over 200 pg/ml was observed (p < 0.05). There was neither a correlation between the iPTH level and left ventricular (LV) mass, nor was there a correlation between the iPTH level and wall thickness. After parathyroidectomy, systolic and diastolic blood pressure, cardiothoracic ratio, LVEF, and LV mass decreased significantly (p < 0.05), but no significant difference was detected in cardiac thickness. In summary, the present data suggest that high levels over 200 pg/ml of the iPTH in long-term hemodialysis patients adversely affect the myocardial function, induce cardiac hypertrophy and cause high arterial blood pressure. After parathyroidectomy, the cardiac function improved with a reduction of cardiac mass and an improvement of cardiac contraction.

Adult↗
PubMed1995

Inhibition of corneal ulceration by tetrapeptidyl hydroxamic acid.

The inhibitory activity of a new peptidyl collagenase inhibitor, FN-439 or tetrapeptidyl hydroxamic acid (H2N-C6H4-CO-Gly-L-Pro-D-Leu-D-Ala-NHOH), was determined against vertebrate collagenases derived from human fibroblast, human polymorphonuclear leukocyte (PMN) and tadpole skin. In addition, the effect of FN-439 in inhibiting corneal ulceration was also investigated with alkali-burned rabbit corneas. FN-439 can block the active site of collagenase, and hydroxamic acid can chelate Zn2+ which is essential for collagenase activity. Furthermore, this compound contains D-amino acids to resist nonspecific host-derived degradative enzymes. In our experiments, corneal ulceration occurred in 5 of the 9 control eyes, but in none of the 9 eyes treated with FN-439 (P < 0.01). The only cellular elements observed at the ulcerated area were PMNs and monocytes. FN-439 appeared to act against PMN collagenase. In addition, we compared the change in the concentration of FN-439 (D-peptide) and the L-form of FN-439 (L-peptide) in aqueous humor aspirated from the rabbit eyes burned with alkali. After incubation for 3 hours, the concentration of the D-peptide was decreased by 3%, while that of the L-peptide was decreased by 60%. FN-439 may be useful for treating noninfectious corneal ulcers because of its potent activity (IC50 = 1 microM) and chemical and biological stabilities.

Animals↗