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Biomedical subjects

H Nishio

Publications and source records attributed to H Nishio.

At least 163 records · Page 9Linked to original sources
PubMed1994

Stimulation of calcium sequestration by mezerein, a protein kinase C activator, in saponized rabbit platelets.

1. The saponin-permeabilized platelet was used to examine the effect of mezerein, a moderate activator of protein kinase C (C-kinase), on the sequestration of Ca2+ to its intracellular storage sites. 2. We found that the activation of C-kinase by mezerein causes the potentiation of the Ca2+ sequestration. 3. It was suggested that C-kinase in platelets might function as a negative feedback regulator for the agonist-induced Ca2+ mobilization and might be involved in its oscillation.

Animals↗
PubMed1994

Identification of a novel first exon in the human dystrophin gene and of a new promoter located more than 500 kb upstream of the nearest known promoter.

The dystrophin gene, which is mutated in patients with Duchenne and Becker muscular dystrophies, is the largest known human gene. Five alternative promoters have been characterized until now. Here we show that a novel dystrophin isoform with a different first exon can be produced through transcription initiation at a previously unidentified alternative promoter. The case study presented is that of a patient with Duchenne muscular dystrophy who had a deletion extending from the 5' end of the dystrophin gene to exon 2, including all promoters previously mapped in the 5' part of the gene. Transcripts from lymphoblastoid cells were found to contain sequences corresponding to exon 3, indicating the presence of new promoter upstream of this exon. The nucleotide sequence of amplified cDNA corresponding to the 5' end of the new transcript indicated that the 5' end of exon 3 was extended by 9 codons, only the last (most 3') of which codes for methionine. The genomic nucleotide sequence upstream from the new exon, as determined using inverse polymerase chain reaction, revealed the presence of sequences similar to a TATA box, an octamer motif and an MEF-2 element. The identified promoter/exon did not map to intron 2, as might have been expected, but to a position more than 500 kb upstream of the most 5' of the previously identified promoters, thereby adding 500 kb to the dystrophin gene. The sequence of part of the new promoter region is very similar to that of certain medium reiteration frequency repetitive sequences. These findings may help us understand the molecular evolution of the dystrophin gene.

Amino Acid Sequence↗
PubMed1994

Amino-terminal deletion of 53% of dystrophin results in an intermediate Duchenne-Becker muscular dystrophy phenotype.

We report a Japanese boy with muscular dystrophy whose clinical symptoms were intermediate between those usually considered typical of Duchenne and Becker muscular dystrophies. The patient had a large inframe deletion extending from exons 3 to 41 of the dystrophin gene, which would be expected to cause the production of a dystrophin protein composing only 53% of the normal polypeptide chain. Such an inframe deletion would be expected to cause Becker muscular dystrophy. We did not obtain evidence for alternative splicing or for RNA editing. Immunocytochemical analysis of skeletal muscle showed that a dystrophin-related polypeptide was detectable with antibody directed against the carboxyl-terminal part of the polypeptide but not with antibodies directed against the amino-terminal part, although labeling by antibody against the carboxyl-terminal was faint and patchy. The severity of the disease in this case may be due to the lack of the amino-terminal, actin-binding domain of dystrophin.

Adolescent↗
PubMed1994

Amplification of selected exons by polymerase chain reaction enables determination of the translational reading frame of dystrophin mRNA resulting from deletion mutations.

Duchenne and Becker muscular dystrophies (DMD and BMD) are severe and mild phenotypes, respectively, of the mutated dystrophin gene. Based on the frameshift theory, an out-of-frame deletion causes DMD, while an in-frame deletion causes BMD. Amplification of deletion-prone exons by polymerase chain reaction (PCR) has been used for the screening of deletion mutations of the dystrophin gene. However, it is difficult to determine the resulting translational reading frame in deleted cases by amplification of the deletion-prone exons. To determine the resulting translational reading frame, we employed a method which selectively amplifies exons affecting the following translational reading frame. Using this method, thirty-three DMD/BMD patients with a deletion mutation in the central region of the dystrophin gene were examined. Twenty-seven of 29 DMD patients had out-of-frame deletions, while only two had in-frame deletions. All four BMD patients had in-frame deletions. Therefore, 93.9% patients fitted the frameshift theory. This method is very useful for clinical diagnosis because of its precision and convenience.

Base Sequence↗
PubMed1994

[Transjugular intrahepatic portosystemic shunt--early experience in eleven liver cirrhosis patients].

Eleven liver cirrhosis patients with variceal bleeding and/or ascites were treated by transjugular intrahepatic portosystemic shunt. Four of the patients were combined with hepatoma, and 2 had portal thrombosis. Ten of the patients were successfully achieved TIPS, but one patient who had portal thrombosis was failed because of portal vein occlusion; success rate of 90%. An average decrease of 14mmHg in portal vein pressure was measured in the 10 patients. All of the successful patients including 4 with hepatoma were observed the disappeared or diminished varices and ascites without technical complication. Mild encephalopathy was encountered in 2 patients but who responded well to medical therapy. Three dimension MRA before TIPS was helpful for understanding the anatomical relationship between portal vein and hepatic vein. It is concluded that TIPS is an effective and safe treatment, indicating for the patients who have uncontrollable variceal bleeding and/or ascites even with hepatoma.

Adult↗
PubMed1994

A novel point mutation (G-1 to T) in a 5' splice donor site of intron 13 of the dystrophin gene results in exon skipping and is responsible for Becker muscular dystrophy.

The mutations in one-third of Duchenne and Becker muscular dystrophy patients remain unknown, as they do not involve gross rearrangements of the dystrophin gene. We now report a defect in the splicing of precursor mRNA (pre-mRNA), resulting from a maternally inherited mutation of the dystrophin gene in a patient with Becker muscular dystrophy. This defect results from a G-to-T transversion at the terminal nucleotide of exon 13, within the 5' splice site of intron 13, and causes complete skipping of exon 13 during processing of dystrophin pre-mRNA. The predicted polypeptide encoded by the aberrant mRNA is a truncated dystrophin lacking 40 amino acids from the amino-proximal end of the rod domain. This is the first report of an intraexon point mutation that completely inactivates a 5' splice donor site in dystrophin pre-mRNA. Analysis of the genomic context of the G-1-to-T mutation at the 5' splice site supports the exon-definition model of pre-mRNA splicing and contributes to the understanding of splice-site selection.

Adult↗
PubMed1993

Synthesis of omega-agatoxin IVA and its related peptides.

A potent and selective P type calcium channel blocker isolated from the venom of the funnel web spider Agelenopsis aperta, omega-agatoxin IVA, and its related peptides were synthesized by the solution procedure. Synthetic omega-agatoxin IVA was found to block high-threshold P-type calcium current in rat Purkinje neuron with the same potency as that reported for the natural product. Its disulfide structure was determined by amino acid analysis, gas-phase sequencing and mass spectrometry of the proteolytic fragments. The N-terminus biotinylated and truncated peptides showed the same disulfide-bond-forming profile and the same activities as those of omega-agatoxin IVA, indicating that the N-terminal basic tripeptide, Lys-Lys-Lys, is not important for both the folding and the expression of the biological activity. However, the Trp residue in the molecule might be essential for the toxin to bind tightly with the channel pores.

Amino Acid Sequence↗
PubMed1993

[Percutaneous arterial prostheses of femoro-femoral bypass: using a new method of Modified Seldinger technique].

An experimental study of percutaneous arterial prostheses of femoro-femoral bypass was performed in 3 dogs using Modified Seldinger technique. Modified Seldinger technique with an arc needle was a newly designed method to penetrate the arterial wall due to introduce a bypass graft into the artery percutaneously. In all dogs, the bypass graft was successfully placed and proved to be effective in excellent blood flow. No significant complication was encountered. It is concluded that this method is feasible in the dog model.

Animals↗
PubMed1993

Modulation of acetylcholine release from the myenteric plexus of guinea-pig ileum by 5-lipoxygenase metabolites of arachidonic acid.

Eicosatetraenoic acid, an inhibitor of 5- and 12-lipoxygenase, and AA861, a selective inhibitor of 5-lipoxygenase, dose dependently inhibited acetylcholine release from the myenteric plexus of guinea-pig ileum induced by electrical field stimulation. Metabolites of arachidonic acid produced by the 5-lipoxygenase pathway, such as 5-hydroxyeicosatetraenoic acid (5-HETE), leukotriene C4, D4 and E4, reversed the inhibitory effect of AA861. Among them, leukotriene D4 was the most potent, having an EC50 value of about 3 nM. The present study shows for the first time that 5-lipoxygenase metabolites may have a modulatory effect on acetylcholine release in the myenteric plexus of guinea-pig ileum.

Acetylcholine↗
PubMed1993

Brain- and muscle-type promoters of the dystrophin gene are selected in peripheral lymphocytes and Epstein Barr virus-transformed lymphoblastoid [correction of lymphoplastoid] cells.

Promoter-specific transcripts of the dystrophin gene in peripheral lymphocytes and Epstein Barr virus-transformed lymphoblastoid cells were analysed using reverse transcription-nested polymerase chain reaction. Two DNA fragments, corresponding to the alternative first exons transcribed from either brain- or muscle-type promoters, were both amplified from cDNA prepared from normal lymphocytes and lymphoblastoid cells. The nucleotide sequences of the amplified products were 100% homologous to the 5' termini of the cDNA of brain- and muscle-type dystrophins, respectively. Neither fragment was amplified from the lymphoblastoid cells of a patient with Duchenne muscular dystrophy, who has a partial deletion involving the brain- and muscle-type promoters in the dystrophin gene. These findings showed that the brain-type as well as the muscle-type promoter of the dystrophin gene was active in lymphocytes and lymphoblastoid cells.

B-Lymphocytes↗
PubMed1993

Relationships between serotonin induced elevation of intracellular Ca2+ concentration and stimulation of Ca2+ influx in blood platelets.

Serotonin (5-HT) caused immediate elevation of intracellular Ca2+ concentration ([Ca2+]i) in blood platelets, and it was completely inhibited by 1 mM EGTA. In Ca2+ replenished platelets, however, 2 mM EGTA did not affect the 5-HT induced elevation of [Ca2+]i when EGTA was applied just before or during the stimulation by 5-HT. At the same concentration 5-HT was also found to enhance Ca2+ influx through the activation of 5-HT2 receptor, but with rather longer latent time. From these results it is suggested that 5-HT induced elevation of [Ca2+]i is caused by mobilization of Ca2+ from intracellular Ca2+ storage sites, but not by direct stimulation of Ca2+ influx. Depletion of such Ca2+ stores might impair the effect of 5-HT on [Ca2+]i. Thus, 5-HT induced augmentation of Ca2+ influx might be secondary to replenishment of the depleted Ca2+ stores which was caused by 5-HT induced internal release of Ca2+. It is concluded that the effects of 5-HT on [Ca2+]i and Ca2+ influx in platelets are manifested sequentially or independently.

Animals↗
PubMed1993

Effects of detergents on binding of 5-hydroxytryptamine3 receptor antagonist [3H]GR65630 to rat cortical membranes.

In the absence of detergent, specific binding of [3H]GR65630, a 5-hydroxytryptamine3 (5-HT3) antagonist, determined in the presence of 5-HT3 receptor antagonist ICS205-930, was at most 30% of the total binding. To decrease the level of nonspecific binding, the effects of detergents on [3H]GR65630 binding to rat cortical membranes were investigated. The use of a detergent (0.1% Lubrol PX or Triton X-100) decreased nonspecific binding, increasing the proportion of specific binding to 70% of total binding. In the presence of 0.1% Triton X-100, binding of [3H]GR65630 was rapid, reversible and saturable at 25 degrees C. The rank order of 5-HT3 receptor active drugs in inhibiting [3H]GR65630 binding was quipazine > ICS205-930 > 2-methyl-5-HT = 5-HT > metoclopramide, which confirmed that [3H]GR65630 efficiently labeled 5-HT3 receptors in the presence of Triton X-100. Triton X-100 improved 5-HT3 receptor binding with rat brain membranes.

Animals↗
PubMed1993

Insertion of a 5' truncated L1 element into the 3' end of exon 44 of the dystrophin gene resulted in skipping of the exon during splicing in a case of Duchenne muscular dystrophy.

We report here the second evidence of retrotransposition of L1, which was found inserted into the dystrophin gene of a patient, causing Duchenne muscular dystrophy (DMD). When the PCR was used to amplify a region of the dystrophin gene encompassing exon 44 from genomic DNA of two Japanese brothers with DMD, it was found to be approximately 600 bp larger than expected. Both the normal and the abnormally large products were amplified from the DNA of their mother. However, the maternal grandparents did not have the abnormal allele, and the mutation must therefore have occurred in the mother. Analysis of nucleotide sequence of the amplified product from a patient disclosed that the insertion was present zero to two bases upstream from the 3' end of exon 44 and that two to four bases of the exon sequence were deleted from the insertion site. The insertion sequence was found to be composed of 606-608 bp and to be almost identical to the inverse complement of 3' portion of the L1 retrotransposon consensus sequence. The dystrophin gene transcript from peripheral lymphocytes of one of the patients was analyzed by using reverse transcription/semi-nested PCR. The size of the amplified product encompassing exon 42 to 46 was smaller than expected. Sequencing of the amplified product disclosed that the sequence of exon 43 was directly joined to that of exon 45. Exon 44 of the transcript was thus shown to be skipped during splicing. This novel mutation of the dystrophin gene has important implications regarding retrotransposition of an active L1 element and provides a new insight into the origins of mutations in the dystrophin gene.

Adult↗
PubMed1993

[Manifesting carriers of Duchenne muscular dystrophy over two generations].

We report a family with manifesting DMD carriers over two generations. Sixty years old female (case 1) suffered from slowly progressive weakness since her thirties. Her youngest daughter aged 30 (case 2) had cramping calf muscle pain since her 5 years old. Progressive muscle weakness developed and lost her ambulation by the age of 20. Grandson of case 1 (son of case 1's eldest daughter who has no clinical symptoms) was diagnosed as DMD with deletion of exon 19-21 in dystrophin gene. Case 1 and case 2 were revealed to be DMD carriers. We speculate that, in this family, X-inactivation process was not random and paternal X was preferentially inactivated by maternal mutant X.

Adult↗
PubMed1993

Intravenous digital subtraction angiography of the internal jugular veins.

92 patients with various head-related symptoms were underwent study with IV-DSA. The width and density of the internal jugular veins were compared with the width and density of the common carotid arteries. The right internal jugular vein was more than twice as broad as the common carotid artery in 58 patients (63%), and was denser than the common carotid artery in 14 patients (15%). On the other hand, the left internal jugular vein was broader than the common carotid artery in 76 patients (83%) and more than twice as broad as the common carotid artery in 19 patients (21%). However, the left jugular vein was narrower than the common carotid artery in 12 patients (13%), and in 5 patients (5%) could not be demonstrated. If it is recalled that the internal jugular veins are sometimes congenitally aplastic or hypoplastic as developmental variations of the confluence of sinuses, the occurrence of complications associated with retrograde catheterization can be minimized.

Adolescent↗
PubMed1992

The evidence for post-meiotic expression of a testis-specific isoform of a regulatory subunit of calcineurin using a monoclonal antibody.

The expression of a regulatory subunit of calcineurin (CaN beta) during rat spermatogenesis was examined in rat testes using a monoclonal antibody Va1. Results showed that a testis-specific isoform of CaN beta was expressed only 3 weeks after birth, when meiosis begins, and increased in amount depending on the maturation of spermatogenesis. The matured sperm, which consists of only post-meiotic cells, is most likely to have only the testis-specific isoform of CaN beta. The brain type isoform of CaN beta was not detected in rat sperm. Immunoblot analysis of testes from different rodent species by a monoclonal antibody Va1 showed that all rodent species examined had their own homologues corresponding to a testis-specific isoform of CaN beta in rats, although they showed distinctively different molecular weights on SDS-PAGE compared to the testis-specific isoform in rats. Each homologue was shown to be specifically expressed in post-meiotic phase of spermatogenesis, as was seen in rats.

Aging↗
PubMed1992

Identification of a src family protein specifically expressed in rat astrocytes by immunohistochemistry and double immunofluorescent study.

Identification of a src-related tyrosine kinase and its regional and cellular distributions were studied in rat brain. The study was performed using a specific antibody raised against a synthetic peptide corresponding to the conserved autophosphorylation site of src-family tyrosine kinases. The antibody (alpha-src antibody) recognized a 43 kDa polypeptide in plasma membrane enriched fraction. The immunohistochemical data revealed that the polypeptide is localized in astrocytes of corpus callosum and fimbria hippocampus. The presence of this src-related protein in astrocytes suggests that it may have some control in their proliferation and differentiation.

Animals↗