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Biomedical subjects

M Matsuo

Publications and source records attributed to M Matsuo.

At least 181 records · Page 10Linked to original sources
PubMed1998

The 27-bp repeat polymorphism in intron 4 of the endothelial cell nitric oxide synthase gene and ischemic stroke in a Japanese population.

Endothelium-derived nitric oxide formed by endothelial constitutive nitric oxide synthase (ecNOS) mediates endothelium-dependent vasodilation and antithrombotic action. We analyzed the distribution of a polymorphism of ecNOS (27-bp repeat in intron 4) in 127 ischemic stroke patients (18 with atherothrombotic, 58 with lacunar, and 51 with silent lacunar stroke) and 91 control subjects. When we assigned the four repeats as allele a, and five repeats as allele b, there was no significant difference between the genotype distribution and allele frequencies in the stroke group and in the control group (0.862 versus 0.868 for the b allele frequency). Moreover, there was also no significant difference in the genotype distribution or allele frequencies among the three stroke subgroups (b allele frequency: 0.889 for atherothrombotic stroke; 0.862 for lacunar stroke; 0.853 for silent lacunar stroke). These findings suggest that there is no overt association between this ecNOS gene polymorphism and ischemic stroke. We found no evidence that this polymorphism may be a genetic factor for the onset of cerebrovascular disease in this Japanese population.

Aged↗
PubMed1998

Denitrification by actinomycetes and purification of dissimilatory nitrite reductase and azurin from Streptomyces thioluteus.

Many actinomycete strains are able to convert nitrate or nitrite to nitrous oxide (N2O). As a representative of actinomycete denitrification systems, the system of Streptomyces thioluteus was investigated in detail. S. thioluteus attained distinct cell growth upon anaerobic incubation with nitrate or nitrite with concomitant and stoichiometric conversion of nitrate or nitrite to N2O, suggesting that the denitrification acts as anaerobic respiration. Furthermore, a copper-containing, dissimilatory nitrite reductase (CuNir) and its physiological electron donor, azurin, were isolated. This is the first report to show that denitrification generally occurs among actinomycetes.

Ascomycota↗
PubMed1998

Novel mutations in aquaporin-2 gene in female siblings with nephrogenic diabetes insipidus: evidence of disrupted water channel function.

Novel mutations of the aquaporin-2 (AQP2) gene have been detected in Japanese female siblings with autosomal-recessive nephrogenic diabetes insipidus. The patients were compound heterozygote for point mutations at nucleotide position 374 (C374T) and at position 523 (G523A) in exon 2 of the AQP2 gene, resulting in substitution of methionine for threonine at codon 125 (T125M) and arginine for glycine at codon 175 (G175R). The water permeability (Pf) of oocytes injected with wild-type complementary RNA increased 9.0-fold compared with the Pf of water-injected oocytes, whereas the increases in the Pf of oocytes injected with T125M and G175R complementary RNA were only 1.7-fold and 1.5-fold, respectively. Immunoblot and immunocytochemistry indicated that the plasma membrane expressions of T125M and G175R AQP2 proteins were comparable to that of the wild-type, suggesting that although neither the T125M nor G175R mutation had a significant effect on plasma membrane expression, they both distorted the structure and function of the aqueous pore of AQP2. These results provide evidence that the nephrogenic diabetes insipidus in patients with T125M and G175R mutations is attributable not to the misrouting of AQP2, but to the disrupted water channel function.

Amino Acid Sequence↗
PubMed1998

Studies on anti-inflammatory agents. VI. Synthesis and pharmacological properties of 2,3-diarylthiophenes.

A series of novel 5-substituted-2,3-diarylthiophenes has been synthesized and found to be active in the rat adjuvant arthritis (AA) model and/or in the yeast-induced hyperalgesia (Randall-Selitto) assay. Among the compounds synthesized herein, 2-(4-fluorophenyl)-3-[4-(methylsulfonyl)phenyl]-5-(trifluoromethyl)thiop hene (6a) exhibited the most potent activities on AA, collagen-induced arthritis (CIA) and the delayed-type hypersensitivity response to type II collagen. 5-Bromo-2-[4-(methylamino)phenyl]-3-[4-(methylsulfinyl)phenyl]thiophene (38) is also a potent inhibitor of AA, CIA, hyperalgesia and in vitro tumor necrosis factor-alpha production.

Adjuvants, Immunologic↗
PubMed1998

Direct evidence that LTC4 and LTB4 but not TXA2 are involved in asthma attacks in children.

There are substantial numbers of reports showing that leukotrienes (LTs) play important roles in adult asthma. No definite evidence has been demonstrated that LTs are involved in asthma attacks in children, although it is highly expected. In this report, we demonstrated that the levels of LTB4 and LTC4 but not thromboxane B2 (TXB2), a stable metabolite of TXA2, were significantly elevated in the bronchoalveolar lavage fluid, which was obtained from intubated and mechanically ventilated children with severe asthma attacks. This is direct evidence that LTB4 and LTC4 predominantly participate in asthma attacks in pediatric patients.

Adolescent↗
PubMed1998

A novel single basepair insertion in exon 6 of the Bruton's tyrosine kinase (Btk) gene from a Japanese X-linked agammaglobulinemia patient with growth hormone insufficiency.

A novel insertion mutation in exon 6 of the Btk gene was detected in a 17 year-old XLA patient with GH insufficiency. We synthesized cDNA from leukocyte total RNA and amplified every region of the Btk-coding sequence. Sequencing of cDNA fragments revealed a single basepair insertion mutation at codon 157 in exon 6 (CAG-->CAAG) which leads to premature termination at codon 193 in exon 7. To confirm the results, we also performed a PCR-DdeI digestion analysis using leukocyte genomic DNA. The PCR product from the patient's genomic DNA was uncleaved with DdeI, as expected. PCR-DdeI digestion analysis of the family members showed that the mother and elder sister were carriers with the mutation and that the younger sister did not carry the mutation.

Adolescent↗
PubMed1998

[Role of biochemical and fibrinolytic parameters on cardiac events associated with Hanshin-Awaji earthquake-induced stress].

Catastrophic stress induced by Hanshin-Awaji earthquake seems to promote rheological deterioration associated with high blood pressure, increased blood viscosity due to hemoconcentration and increased fibrinogen level. These changes lead to prolonged endothelial cell dysfunction demonstrating high levels of von Willebrand factor, tissue type plasminogen activator and plasmin.alpha 2 plasmin inhibitor complex, and accelerate fibrin turnover as the result of a high D-dimer level from the post earthquake period until 4-6 months later. There were remarkable changes in biochemical parameters except for uric acid, BUN, triglyceride level. An increase in these acute changes caused by mental and physical stress might trigger obstructive thrombus in coronary arteries in the elderly after an earthquake. In conclusion, earthquake induced stress could be considered a transient cardiovascular risk factor.

Blood Pressure↗
PubMed1998

Endothelial cell damage and angiotensin-converting enzyme insertion/deletion genotype in elderly hypertensive patients.

OBJECTIVES: The purpose of this study was to investigate the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) genotype and endothelial cell dysfunction or hypercoagulable state in elderly hypertensive patients. BACKGROUND: Angiotensin-converting enzyme (ACE) insertion/ deletion (I/D) polymorphism was recently reported to be associated with various cardiovascular diseases. However, the precise mechanism of this association remains unknown, and some confounding factors might also affect the association. Endothelial cell dysfunction and coagulation activation play important roles in both the atherosclerotic process and the onset of cardiovascular events. METHODS: We identified the ACE I/D genotype and measured the plasma levels of markers of endothelial cell damage (von Willebrand factor [vWF] and thrombomodulin) and of coagulation activation (prothrombin fragment F1 + 2 [F1 + 2]) in 318 asymptomatic elderly patients with hypertension, aged 59-93 years. RESULTS: The vWF level was significantly higher in those with the DD genotype (n = 54) than in those with the II genotype (n = 131, p < 0.0001) or with the ID genotype (n = 133, p < 0.0001). The TM levels were also higher in patients with the ID genotype (p < 0.005) and the DD genotype (p < 0.01) than in those with the II genotype. There were no differences in F1 + 2 level among the groups. Positive correlations of systolic blood pressure with levels of both vWF and thrombomodulin were found predominantly in patients with the II genotype (both p < 0.001), but no correlation was noted in those with the DD genotype. CONCLUSIONS: Considering the increased plasma levels of both endothelial cell-derived markers in the hypertensive patients with ACE DD genotype, we speculate that the ACE D allele is a risk factor for the development of hypertensive cardiovascular disease associated with endothelial cell damage.

Aged↗
PubMed1998

Splicing error due to a splice acceptor site mutation in the ALD gene identified in a Japanese childhood cerebral adrenoleukodystrophy case.

X-linked adrenoleukodystrophy (ALD) is characterised by progressive multifocal demyelination of central nervous system and adrenocortical insufficiency. This disorder has been also associated with mutations in the ALD gene, encoding an ATP-binding transporter which is located in the peroxisomal membrane. Defect of the gene may lead to impaired peroxisomal beta-oxidation and increase of serum and tissue very long chain fatty acids (VLCFAs). Here we report the results of analysis of the ALD gene in a Japanese patient with childhood cerebral ALD. In our patient, by sequencing of the ALD cDNA, an 8 bp insertion (ACCCCCAG) was detected at the start of exon 9, which corresponded to nucleotides from position -1 to -8 of the 3' splice acceptor site of intron 8. Sequencing of genomic DNA showed a single nucleotide substitution at position-10 of the 3' splice acceptor site of intron 8 replacing a G with an A which activated a cryptic splice acceptor site. It is concluded that a splicing error was induced by a point mutation that created a novel splice acceptor site. This insertion created a nonsense codon downstream, producing a truncated ALD protein. His mother and younger sister with increased VLCFA ratios were heterozygotes of normal and mutant ALD genes.

ATP-Binding Cassette Transporters↗
PubMed1997

Disruption of the splicing enhancer sequence within exon 27 of the dystrophin gene by a nonsense mutation induces partial skipping of the exon and is responsible for Becker muscular dystrophy.

The mechanism of exon skipping induced by nonsense mutations has not been well elucidated. We now report results of in vitro splicing studies which disclosed that a particular example of exon skipping is due to disruption of a splicing enhancer sequence located within the exon. A nonsense mutation (E1211X) due to a G to T transversion at the 28th nucleotide of exon 27 (G3839T) was identified in the dystrophin gene of a Japanese Becker muscular dystrophy case. Partial skipping of the exon resulted in the production of truncated dystrophin mRNA, although the consensus sequences for splicing at both ends of exon 27 were unaltered. To determine how E1211X induced exon 27 skipping, the splicing enhancer activity of purine-rich region within exon 27 was examined in an in vitro splicing system using chimeric doublesex gene pre-mRNA. The mutant sequence containing G3839T abolished splicing enhancer activity of the wild-type purine-rich sequence for the upstream intron in this chimeric pre-mRNA. An artificial polypurine oligonucleotide mimicking the purine-rich sequence of exon 27 also showed enhancer activity that was suppressed by the introduction of a T nucleotide. Furthermore, the splicing enhancer activity was more markedly inhibited when a nonsense codon was created by the inserted T residue. This is the first evidence that partial skipping of an exon harboring a nonsense mutation is due to disruption of a splicing enhancer sequence.

Adult↗
PubMed1997

Six novel transcripts that remove a huge intron ranging from 250 to 800 kb are produced by alternative splicing of the 5' region of the dystrophin gene in human skeletal muscle.

The dystrophin gene, which is mutated in patients with Duchenne and Becker muscular dystrophies, comprises 79 exons and is thus the largest known human gene. A full spectrum of splicing of dystrophin transcript has not been elucidated yet. In this study, 6 novel alternative splicing reactions were discovered in the 5' region by amplifying the cDNA corresponding to exons M1 through 18. Two of these novel transcripts maintain the translational reading frame and are presumed to produce truncated dystrophin, while the other four have disrupted reading frames. The physical distance between splice donor and acceptor sites ranged from 250 kb to 800 kb. Furthermore, the same six alternative splicing products were obtained from mouse skeletal muscle cDNA. This indicated that these novel alternative splicing events are conserved in humans and mice.

Alternative Splicing↗
PubMed1997

Propofol produces anticonflict action by inhibiting 5-HT release in rat dorsal hippocampus.

We examined the effect of propofol, an injectable anesthetic agent on conflict behavior in a Vogel type conflict test and on release of serotonin (5-hydroxytryptamine, 5-HT) in the dorsal hippocampus using an in vivo microdialysis method in rats. Propofol (20 and 40 mg/kg, i.p.) dose-dependently suppressed elevated 5-HT release normally seen in a conflict situation and concomitantly attenuated conflict behavior. These findings suggest that propofol exerts an antianxiety action by inhibiting 5-HT neuronal activity in the dorsal hippocampus.

Anesthetics, Intravenous↗