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Biomedical subjects

M Yasuda

Publications and source records attributed to M Yasuda.

At least 109 records · Page 6Linked to original sources
PubMed1999

A mutation in the microtubule-associated protein tau in pallido-nigro-luysian degeneration.

We detected a missense mutation in exon 10 of tau that causes a substitution at codon 279 (N279K) in a Japanese patient with a familial background of parkinsonism and dementia originally described as pallido-nigro-luysian degeneration. This mutation is the same as one seen in a Caucasian family with pallido-ponto-nigral degeneration. The similarities between these two families suggest a common genetic mechanism that may account for the peculiar distribution of neuroglial degeneration with tauopathy.

Amino Acid Sequence↗
PubMed1999

Association study of a polymorphism of nonerythroid alpha-spectrin gene with schizophrenia.

The specificity of cytoarchitectural abnormalities in limbic structures of patients with schizophrenia and their contributions towards the etiology of schizophrenia remain unknown. We have recently reported an increased breakdown of nonerythroid alpha-spectrin (fodrin), a major component of neuronal cytoskeletal proteins, in schizophrenic left superior temporal cortices [Kitamura et al., 1998: Biol Psychiatry 43:254-262], suggesting that polymorphisms of the alpha-spectrin gene might contribute to the vulnerability to schizophrenia. We screened for genetic variations associated with schizophrenia through the C-terminus sequences of the human nonerythroid alpha-spectrin gene (SPTAN1) spanning two EF-hands and also tested a possible contribution of the polymorphism to the development of schizophrenia by an association study. We found a polymorphic region of an intron located in the second EF-hand of SPTAN1 gene. There was no significant difference between patients with schizophrenia and controls in allele frequencies or genotype distribution. There is evidence that the Psh BI SPTAN1 gene polymorphism does not play a major role in the genetic component of schizophrenia.

Adult↗
PubMed1999

BNIP3alpha: a human homolog of mitochondrial proapoptotic protein BNIP3.

Apoptosis is regulated by interaction of viral and cellular BCL-2 family antiapoptotic proteins with various pro-apoptotic proteins, several of which are also members of the BCL-2 family. Cellular protein BNIP3 is a BCL-2 family proapoptotic protein that interacts with viral antiapoptosis proteins such as adenoviruses E1B-19K and EBV-BHRF1 and cellular antiapoptosis proteins such as BCL-2 and BCL-xL. Database searches indicate that the human genome encodes an open reading frame for a protein, BNIP3alpha, that shares substantial homology with BNIP3. The BNIP3alpha open reading frame encodes a protein of 219 amino acids that contains a conserved BH3 domain and a COOH-terminal trans-membrane domain, characteristic of several BCL-2 family proapoptotic proteins. BNIP3alpha interacts with viral antiapoptosis protein E1B-19K and cellular antiapoptosis proteins BCL-2 and BCL-xL. Overexpression of BNIP3alpha in transfected cells results in apoptosis and suppresses the antiapoptosis activity of E1B-19K and BCL-xL. Like BNIP3, BNIP3alpha seems to be predominantly localized in mitochondria. These results suggest that BNIP3alpha is a structural and functional homologue of BNIP3. BNIP3 and BNIP3alpha seem to be the first examples of homologues among the various human proapoptotic proteins. Northern blot analysis reveals that BNIP3alpha is expressed ubiquitously in most human tissues. In contrast, BNIP3 is expressed well in several human tissues and less abundantly in certain tissues such as placenta and lung. These results suggest that although BNIP3 and BNIP3alpha may promote apoptosis simultaneously in most human tissues, BNIP3alpha may play a more universal role.

Adenovirus E1B Proteins↗
PubMed1999

A pedigree with a novel presenilin 1 mutation at a residue that is not conserved in presenilin 2.

OBJECTIVE: To disclose a novel mutation of the presenilin 1 (PS1) gene responsible for early-onset Alzheimer disease and to clarify genotype-phenotype correlation that should help to establish the function of this protein. BACKGROUND: The PS1 and presenilin 2 (PS2) genes carry missense mutations in families with Alzheimer disease. The PS1 and PS2 proteins have similar structures, and all presently known mutations are in nucleotides coding for amino acids that are conserved between the 2 presenilins. METHODS: Sequence and restriction fragment length polymorphism analyses of PS1 gene of DNA from a pedigree with early-onset Alzheimer disease. RESULTS: Sequence analysis disclosed a novel PS1 mutation in a pedigree of Japanese origin with early-onset Alzheimer disease. This mutation, which is predicted to cause a missense substitution of lysine for glutamic acid, occurred at codon 123 of PS1 that was not a conserved residue in PS2. The 2 patients of this pedigree shared an early clinical phenotype consisting of later-onset, progressive aphasia, but preserved visuospatial ability, which was indistinguishable from those of other PS1-associated Alzheimer disease cases. CONCLUSION: These results demonstrate that a missense mutation in a region not conserved between PS1 and PS2 can cause Alzheimer disease.

Age of Onset↗
PubMed1999

Effects of Sho-saiko-to, a Japanese herbal medicine, on hepatic fibrosis in rats.

It has been shown that lipid peroxidation is associated with hepatic fibrosis and stellate cell activation. Sho-saiko-to (TJ-9) is an herbal medicine, which is commonly used to treat chronic hepatitis in Japan, although the mechanism by which TJ-9 protects against hepatic fibrosis is not known. As a result, we assayed the preventive and therapeutic effects of TJ-9 on experimental hepatic fibrosis, induced in rats by dimethylnitrosamine (DMN) or pig serum (PS), and on rat stellate cells and hepatocytes in primary culture, and assessed the antioxidative activities and the active components of TJ-9. Male Wistar rats were given a single intraperitoneal injection of 40 mg/kg DMN or 0.5 mL PS twice weekly for 10 weeks. In each model, rats were fed a basal diet throughout, or the same diet, which also contained 1.5% TJ-9, for 2 weeks before treatment or for the last 2 weeks of treatment. TJ-9 suppressed the induction of hepatic fibrosis, increased hepatic retinoids, and reduced the hepatic levels of collagen and malondialdehyde (MDA), a production of lipid peroxidation. Immunohistochemical examination showed that TJ-9 reduced the deposition of type I collagen and the number of alpha-smooth muscle actin (alpha-SMA) positive-stellate cells in the liver and inhibited, not only lipid peroxidation in cultured rat hepatocytes that were undergoing oxidative stress, but also the production of type I collagen, alpha-SMA expression, cell proliferation, and oxidative burst in cultured rat stellate cells. In addition, TJ-9 inhibited Fe2+/adenosine 5'-diphosphate-induced lipid peroxidation in rat liver mitochondria in a dose-dependent manner and showed radical scavenging activity. Among the active components of TJ-9, baicalin and baicalein were found to be mainly responsible for the antioxidative activity. These findings suggest that Sho-saiko-to (TJ-9) functions as a potent antifibrosuppressant by inhibition of lipid peroxidation in hepatocytes and stellate cells in vivo.

Animals↗
PubMed1999

Suppressive effects of estradiol on dimethylnitrosamine-induced fibrosis of the liver in rats.

As a model for the analysis of the fibrosuppressive role of estradiol, hepatic fibrosis was induced in male and female rats by the administration of a single dose of dimethylnitrosamine (DMN). The fibrotic response of the male liver after DMN treatment was significantly stronger than that of the female liver. In the male DMN model, estradiol reduced hepatic mRNA for type I and III procollagens and the tissue inhibitor of metalloproteinase-1 (TIMP-1), as well as deposition of type I and III collagen protein total hepatic collagen and malondialdehyde (MDA), a product of lipid peroxidation. Concomitant administration of a neutralizing antibody against rat estradiol enhanced fibrogenesis, as judged by the same parameters. Ovariectomy in the female model had a fibrogenic effect, inducing the hepatic expression of both types of procollagen and TIMP-1; in addition, the number of alpha-smooth muscle actin (alpha-SMA)-positive cells in the liver increased; estradiol replacement was fibrosuppressive in the castrated-female model. In rat hepatic stellate cells incubated in primary culture with estradiol, cell number, type I collagen production, and alpha-SMA expression were all reduced. These findings suggest that estradiol suppressed the induction of hepatic fibrosis, and may in part underlie the more rapid progression in males of hepatic fibrosis and its complications.

Animals↗
PubMed1999

An experimental allergic conjunctivitis induced by topical and repetitive applications of Japanese cedar pollens in guinea pigs.

OBJECTIVE AND DESIGN: To develop a model of experimental allergic conjunctivitis, guinea pigs were given repetitive and topical applications of Japanese cedar pollen as an antigen, and the resulting allergic reaction was characterised. SUBJECTS: Male Hartley guinea pigs. TREATMENT: Guinea pigs were sensitised by insertion of small gelatin sponge pieces (3 pieces/eye, both eyes) containing the pollen extracts + Al(OH)3 into the palpebra superior/inferior sulci of both eyes for 8 h/day for 6 days. Then the animals were challenged by dropping pollen suspension in each eye once every week. METHODS: Time-course changes of conjunctivitis intensity score (CIS), which represents oedema and redness, and scratching frequency, and gamma1 and IgE levels in sera were assessed following the respective 1st-17th challenges. Ophthalmic lavage was performed to assay for albumin leakage and migrated leukocytes at each of the odd-numbered challenges. RESULTS: At relatively early stages of the repeated challenge, only a gradual increase of CIS was observed. However, thereafter, considerably higher CIS with the maximum at 30 min after the challenge was provoked at the 12th-17th challenges. Quite interestingly, there were differences in the CIS between the right and left eyes, depending on the individuals. Scratching, and albumin leakage and neutrophil influx into the lavage fluid were also developed during the challenges. Although the anaphylactic antibodies against the antigen were detected in the sera from half of the animals, the levels were not correlated to severity of the symptoms. CONCLUSIONS: The present sensitisation/challenge procedures are unique in terms of topical application of antigen. The lack of any correlation between the levels of the anaphylactic antibodies and severity of anaphylactic symptoms, and the difference of CIS between the left and right eyes of an individual strongly suggest that the anaphylactic antibodies are formed in locally limited tissue surrounding an eye. The present method should be useful for analysing the mechanisms of allergic conjunctivitis.

Administration, Topical↗
PubMed1999

Purification and characterization of a soybean-milk-coagulating enzyme from Bacillus pumilus TYO-67.

Bacillus pumilus TYO-67 was isolated from tofu (soybean curd) as the best producer of a soybean-milk-coagulating enzyme, induced by the addition of soybean protein to the growth medium. The enzyme was purified approximately 30-fold with an 11% yield. The homogeneous preparation of the enzyme showed that it is a monomer with a molecular mass of about 30 kDa and has an isoelectric point at pH 9.75. The results of amino acid composition analyses showed that the enzyme is rich in alanine, aspartic acid, glycine, serine and valine. Although the amino-terminal amino acid (alanine) was identical with that of subtilisins, the amino-terminal sequence was different from those of subtilisins. The alpha-helix content of the enzyme was calculated to be 28.2%. The optimum pH and temperature were observed at 6.0-6.1 and 65 degrees C respectively. The enzyme was significantly activated by the addition of 1 mM Mn2+, Ca2+, Mg2+, and Sr2+ ions in the reaction mixture, and its thermal stability was significantly increased by Ca2+ ion.

Amino Acid Sequence↗
PubMed1999

Stimulation of in vitro angiogenesis by hydrogen peroxide and the relation with ETS-1 in endothelial cells.

The purpose of this study was to examine the effect of hydrogen peroxide (H2O2) on angiogenesis in cultured endothelial cells. Endothelial cells obtained from bovine thoracic aorta (BAECs) were cultured between two layers of collagen type I to measure the tube formation which is a marker for angiogenesis. Addition of H2O2 (0.1-10 microM) to endothelial cells for various periods increased the rate of tube formation. The maximum stimulation of the tube formation was obtained when cells were exposed to 1 microM H2O2 for 30 min, and the enhancement of tube formation was blocked by catalase (10 U/ml). Both proliferation and migration of BAEC which are known to affect angiogenesis, were also stimulated by the addition of H2O2 (0.1 and 1 microM). Thus relatively low concentrations of H2O2 stimulated angiogenesis, proliferation and migration. Ets-1 is a member of the ets gene family of transcription factors, which binds to the ets binding motif in the cis-acting elements and regulates the expression of certain genes such as proteases including urokinase plasminogen activator (u-PA) and matrix metalloproteinase-1 (MMP-1). Interestingly, H2O2 increased the ets-1 mRNA level in BAECs compared with the basal level. The H2O2-stimulated angiogenesis was completely blocked by an ets-1 antisense oligonucleotide, but not by a mismatched oligonucleotide. These findings indicate that low concentrations of H2O2 stimulate angiogenesis in BAECs, and the stimulation mechanisms may partially involve the enhancement of proliferation and migration. Moreover, the H2O2-induced angiogenesis is likely to be mediated by the transcription factor ets-1.

Animals↗
PubMed1999

Theoretical investigation of fructose 1,6-diphosphate production and simultaneous ATP regeneration by conjugated enzymes in an ultrafiltration hollow-fiber reactor.

The performance of an ultrafiltration hollow-fiber reactor, in which enzymatic synthesis of fructose 1,6-diphosphate (FDP) from glucose and enzymatic ATP regeneration are performed simultaneously, was analyzed theoretically. The reaction system consists of three-step synthetic reactions catalyzed by glucokinase (GK), phosphoglucose isomerase and phosphofructokinase, and the ATP regeneration reaction catalyzed by acetate kinase. Based on a simple analytical model developed previously in which the liquid flowing in a tube was assumed to be plug flow and the radial concentration gradients in the tubes and shell side space were both neglected, a computer program was developed to calculate the concentration profiles of all the components along the flow direction in the tubes and shell side space of the reactor. From the FDP concentrations at the reactor outlet calculated under various operational conditions, reactor performances such as the FDP yield and the ATP recycle number were determined. The calculation showed the interesting phenomenon that under some conditions the FDP yield was higher when GK concentration was lower.

Journal Article↗
PubMed1999

Experimental investigation of fructose 1,6-diphosphate production and simultaneous ATP regeneration by conjugated enzymes in an ultrafiltration hollow-fiber reactor.

The enzymatic synthesis of fructose 1,6-diphosphate (FDP) from glucose and the enzymatic ATP regeneration were performed simultaneously in an ultrafiltration hollow-fiber reactor using both the purified enzymes and the crude cell extract of Bacillus stearothermophilus. The process consisted of the three-step synthetic reactions catalyzed by glucokinase, phosphoglucose isomerase and phosphofructokinase, and the ATP regeneration reaction catalyzed by acetate kinase. The experimental results of the yield and the recycle number agreed well with the theoretical predictions calculated using a computer program developed in our preceding study. This proved the validity of this computer program for predicting or analyzing the reactor performance.

Journal Article↗
PubMed1999

Peptide synthesis catalyzed by organic solvent-stable protease from Pseudomonas aeruginosa PST-01 in monophasic aqueous-organic solvent systems.

The equilibrium yields of the peptide Cbz-Arg-Leu-NH2 synthesized from Cbz-Arg and Leu-NH2 using the PST-01 protease in the presence of organic solvents were investigated under various conditions. The equilibrium yields depended little on the concentration of the carboxyl component, but significantly on the concentration of the nucleophile. The optimum temperature and pH for a high equilibrium yield were 30 degrees C and greater than 5.0, respectively. Under optimum conditions the equilibrium yields were 71.6% and 87.7% in the presence of 50% (v/v) DMF and 60% (v/v) DMSO, respectively. Furthermore, the PST-01 protease also catalyzed the syntheses of the dipeptides Cbz-Lys-Leu-NH2, Cbz-Ala-Leu-NH2, Cbz-Ala-Phe-NH2, Cbz-Arg-Leu-NH2, and Cbz-Lys-Phe-NH2 with equilibrium yields of more than 60% in the presence of 50% (v/v) DMF and 50 mM sodium phosphate buffer (pH 7.0).

Journal Article↗
PubMed1999

Purification and characterization of lipase from Rhizopus chinensis cells.

Lipase from Rhizopus chinensis cells was purified and characterized. The molecular mass of purified lipase was 28.4 kDa and the optimal temperature and pH for its activity were 37 degrees C and 5.5, respectively. Purified lipase exhibited high hydrolytic activity against fatty acid methyl esters such as methyl caprylate, methyl laurate, and methyl palmitate. Freeze-dried lipase catalyzed the transesterification between olive oil and methyl laurate in n-hexane.

Journal Article↗
PubMed1999

Purification and characterization of organic solvent-stable protease from organic solvent-tolerant Pseudomonas aeruginosa PST-01.

An organic solvent-stable protease (PST-01 protease) in a culture broth of organic solvent-tolerant Pseudomonas aeruginosa PST-01 was purified by successive hydrophobic interaction chromatography using Butyl-Toyopearl gels. The purified enzyme was homogeneous as determined by SDS-polyacrylamide gel electrophoresis. PST-01 protease had a molecular mass of 38 kDa. The optimum temperature and pH for casein hydrolysis were 55 degrees C and 8.5, respectively. PST-01 protease was stable at pH 8-12 and below 50 degrees C and was determined to be a metalloprotease which was inhibited by EDTA, 1,10-phenanthroline, and phosphoramidon. PST-01 protease inhibited by EDTA was reactivated completely by the addition of zinc or cobalt ions. The stability of PST-01 protease in solutions containing water-soluble organic solvents or alcohols was higher than that in the absence of organic solvent. Furthermore, in general, PST-01 protease was more stable than commercially available proteases, namely, subtilisin Carlsberg, thermolysin, and alpha-chymotrypsin, in the presence of water-soluble organic solvents or alcohols.

Journal Article↗
PubMed1999

Enzymatic synthesis of fructose 1,6-diphosphate with ATP regeneration in a batch reactor and a semibatch reactor using purified enzymes of Bacillus stearothermophilus.

The enzymatic synthesis of fructose 1,6-diphosphate (FDP), an important glycolytic intermediate whose applications in the field of medicine have generated a great deal of interest, was performed in a batch reactor and a semibatch reactor. Using the batch reactor, FDP was first synthesized from glucose by three enzymatic reactions and the ATP consumed was regenerated simultaneously using conjugated enzymes, all of which were purified from crude cell extract of thermophilic Bacillus stearothermophilus. The results of the experiments performed using several enzyme concentrations suggest the existence of an optimum concentration for each enzyme at which the maximum FDP yield can be attained. Since the thermal decomposition of acetyl phosphate reduced the yield of FDP in the batch reactor, the use of a semibatch reactor in which acetyl phosphate was fed continuously was examined. The yield of FDP was improved but the time required to complete the reaction was longer, resulting in a lower productivity of FDP. The yields observed in the two reactors using various enzyme and substrate concentrations were in good agreement with the theoretical predictions calculated based on differential equations derived for the system using the rate equations and the kinetic parameters determined previously. This means that these equations can be used for the analysis of the experimental results as well as for determining the optimum experimental conditions.

Journal Article↗
PubMed1999

Enzymatic production of fructose 1,6-diphosphate using crude cell extract of Bacillus stearothermophilus.

The enzymatic production of fructose 1,6-diphosphate (FDP) from glucose was performed in a batch reactor and a semibatch reactor using the crude cell extract of Bacillus stearothermophilus which contains all four enzymes required for the synthesis. The experimental results of the yield and the time courses of FDP production obtained using various enzyme concentrations were in good agreement with the theoretical predictions calculated based on the differential equations including the rate equations of the four enzymes, which were determined using the purified enzymes of B. stearothermophilus.

Journal Article↗