Biomedical subjects

M Yoshida

Publications and source records attributed to M Yoshida.

At least 1,279 records · Page 71Linked to original sources

PubMed1995

A new strategy of gene trapping in ES cells using 3'RACE.

"Gene trapping" in embryonic stem (ES) cells is a novel approach to identify a series of genes in mammals concomitant with the production of the corresponding mutant mice. However, this approach is currently unable to identify genes that are not expressed in ES cells. Here we describe a strategy to identify gene trapping clones which is not based on expression of a reporter gene. It uses the neor gene which lacks a polyadenylation signal and has a splice donor signal. Expression of the neor gene as fusion transcripts with the 3' end containing the polyadenylation signal of tagged genes allows the identification of these clones by 3' rapid amplification of the cDNA end in undifferentiated ES cells, even if the genes are not expressed in ES cells. Amplification was observed in about 25% of G418-resistant clones. Sequence analyses suggested the amplifications represent gene trapping events. The feasibility of this approach was further assessed by analysing one clone, PAT-12, in detail.

Amino Acid Sequence↗

PubMed1995

Active oxygen species in formation of acute gastric mucosal lesions induced by thermal injury in rats.

Active oxygen species generated by circulating leukocytes and released from the gastric mucosa were measured in the process of acute gastric mucosal lesion formation after thermal injury in rats. Alterations of luminol-dependent chemiluminescence activities generated by leukocytes obtained from the gastric vein and the inferior vena cava were approximately same. A decrease in chemiluminescence activity 15 min after thermal injury and a significant increase in chemiluminescence activity 5 hr after thermal injury were observed in leukocytes from both veins. From 15 min to 12 hr after thermal injury, luciferin-dependent chemiluminescence activities were significantly higher than that of the control group. Oral administration of rebamipide resulted in decreased mucosal lesion formation. Rebamipide, an antiulcer agent that protects the mucosa from damage in various animal models decreased chemiluminescence activities only released from the gastric mucosa but not from circulating leukocytes. These results suggest that two different pathways of active oxygen species formation may exist in the pathogenesis of acute gastric mucosal lesions after thermal injury.

Acute Disease↗

PubMed1995

The role of ATP-sensitive potassium channels in striatal dopamine release: an in vivo microdialysis study.

We used in vivo brain microdialysis to investigate the role of adenosine triphosphate (ATP)-sensitive potassium (KATP) channels in dopamine (DA) release regulated by DA autoreceptors in the rat striatum. Local infusions of the KATP channel opener nicorandil (10(-5)-10(-3) M) into the striatum through the dialysis membrane produced dose-dependent decreases in extracellular concentrations of DA. Local application of the D2 receptor antagonist (-)-sulpiride (SLP, 10(-5) M) or the KATP channel blocker quinine (QIN, 10(-3) M) produced significant increases in extracellular concentrations of DA. Nicorandil (10(-3) M) significantly blocked SLP (10(-5) M)- or QIN (10(-3) M)-induced increases in DA levels in the striatum. These results suggest that activation or inhibition of the KATP channel in the striatum causes decreases or increases, respectively, in endogenous DA release in vivo. Furthermore, SLP-induced increases in DA levels caused by blocking the tonic activation of DA autoreceptors are inhibited by the activation of KATP channels. These data suggest that striatal DA autoreceptors may inhibit DA release tonically by activating the KATP channel.

Adenosine Triphosphate↗

PubMed1995

Combination chemotherapy of carboplatin and cytosine arabinoside for high-risk leukemia: a pilot study.

Fourteen patients with high-risk leukemia (six with relapsed AML, three with relapsed ALL, one with AML-M0, four with CML in myeloid blastic crisis) were treated with a combination chemotherapy of carboplatin (200-300 mg/m2/day) and cytosine arabinoside (100 mg/m2/day) by 24 h continuous infusion for 5-7 days. Five patients (35.7%) achieved complete remission including two patients complicated with myelofibrosis (one with AML-M0 and one with CML in myelo-megakaryocytic crisis). Thirteen patients had nausea and vomiting, five patients had severe, prolonged neutropenia for which it was necessary to administer granulocyte colony-stimulating factor and six patients had severe thrombocytopenia. We concluded that this regimen is effective for the treatment of high-risk leukemia.

Adolescent↗

PubMed1995

Antigenic analysis of Japanese encephalitis viruses in Asia by using monoclonal antibodies.

Based on our previous study using monoclonal antibodies against three Japanese encephalitis (JE) virus strains, Nakayama-RFVL, Beijing 1 and Kamiyama, 25 JE virus strains isolated mainly in Japan and some from Southeast Asia between 1935 and 1979 fell into five antigenic groups, Nakayama, Beijing 1, Kamiyama, Muar and 691004. In the present study, monoclonal antibodies against Muar and 691004 strains were produced to analyze immunological characteristics of JE virus in detail. We obtained the Muar group-specific antibody and three anti-691004 monoclonal antibodies which showed different reactivities. Furthermore, antigenic comparison of the 22 JE virus strains isolated in Asia between 1963 and 1984 was performed by using the 15 monoclonal antibodies characterized by the different reactivities against the above five antigenic groups. Of these 22 strains, the 17 strains reacted with the Kamiyama group-specific monoclonal antibody, but anti-Nakayama, anti-Beijing 1 and anti-Muar group-specific monoclonal antibodies showed no reactivities with any of the strains. This suggested that the currently prevalent JE virus strains in Asia belonged to the Kamiyama group. The other five strains, ThCMP 1982, KE083, KE093, 733913 and Ling, did not react with the above four group-specific monoclonal antibodies, but all except the KE093 strain showed a similar pattern to the Kamiyama strain on the basis of the reactivities against the other 11 antibodies. The KE093 strain isolated from Thailand in 1983 showed immunologically outstanding difference from other strains.

Animals↗

PubMed1995

Effects of acoustic overstimulation on 2f1-f2 distortion product in the cochlear microphonics.

The cochlear microphonics (CM) in response to two-tone stimuli as well as the threshold of compound action potential (CAP) were measured before and after exposure to 4 kHz pure tone at 100 dB SPL for 10 min. Although the loss of CM output at the primary frequencies was limited to around 2 dB, the 2f1-f2 distortion products in the CM (CM-DPs) were markedly reduced immediately after the exposure, especially at low primary levels (i.e. less than 65 dB). The low level CM-DPs recovered gradually near the initial level within 7 days from the exposure. The elevation of CAP threshold closely paralleled with the reduction of CM-DPs in not only the acute phase but also in the recovery phase from the exposure. These results show that the active transduction process in the cochlea was affected by acoustic overstimulation. This impairment of the active transduction was postulated to play an important role in developing the noise induced temporary threshold shift.

Acoustic Stimulation↗

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

Detection of varicella-zoster virus DNA in maternal breast milk from a mother with herpes zoster.

BACKGROUND: We previously reported that varicella-zoster virus (VZV) DNA was detected by polymerase chain reaction (PCR) from maternal breast milk of a post-partum mother with chickenpox. OBJECTIVES: We tried to decide the route of VZV contamination to maternal milk. CASE REPORT: A 22-year-old woman developed herpes zoster on her right Th3-4 dermatome. RESULTS AND CONCLUSIONS: VZV DNA was detected by PCR from peripheral blood and the maternal milk of the right breast, but not from the maternal milk of the left breast. These results suggest that VZV in maternal milk may not derive from VZV-infected mononuclear cells in peripheral blood, but from the VZV-infected epitheliums of the lacteal gland.

Journal Article↗

PubMed1995

Solution structure of endothelin B receptor selective antagonist RES-701-1 determined by 1H NMR spectroscopy.

The three-dimensional structure of the endothelin B receptor (ETB) selective antagonist RES-701-1 has been determined by 1H NMR in deuterated dimethyl sulphoxide. RES-701-1 consists of 16 amino acid residues with a novel internal linkage between the beta-carboxyl group of Asp9 and the alpha-amino group of Gly1. The structural calculations were carried out with the combined use of distance geometry and simulated annealing. The result indicates that RES-701-1 adopts an extraordinary folding; the 'tail' (Trp10-Trp16) passes through the 'ring' region (Gly1-Asp9). Several critical NOEs directly support this extraordinary folding. The folding of RES-701-1 turned out to be the same as that Frèchet et al. calculated for RP 71955 which possesses the same internal linkage as RES-701-1. The obtained structure suggested that the region consisting of Thr6, Ala7, Tyr14 and Tyr15 and/or, the region consisting of Asn2, Tyr14 and Tyr15 are involved in a binding with ETB.

Amino Acid Sequence↗

PubMed1995

Endoscopic assessment of invasion of colorectal tumors with a new high-frequency ultrasound probe.

The present study was carried out to clarify the usefulness of and problems associated with a new ultrasound probe in the assessment of invasion of colorectal tumors. Normal colorectal wall of 23 resected specimens from colorectal cancer cases was examined in vitro with the probe. Fifty-one patients with colorectal carcinoma and 16 patients with rectal carcinoid tumor were presurgically examined using the probe via the biopsy channel of a conventional colonoscope. After endoscopic and ultrasonographic examination, 27 patients underwent endoscopic resection and 40 underwent surgical resection. The ultrasonographic findings were compared with histologic findings in all cases. Carcinomas and carcinoid tumors were visualized as an echo-poor region with the probe. The overall accuracy rate for depth of invasion was 76% (39/51) for colorectal cancer. The accuracy rates for tumors limited to the mucosa and tumors invading the submucosa were 83% and 90%, respectively; these rates were higher than those for tumors invading the muscularis propria (50%) and beyond the muscularis propria (73%). In all 16 cases of carcinoid tumor, the depth of invasion was accurately shown to be limited to the submucosa. This probe is useful to assess invasion of colorectal tumors, especially small and flat lesions limited to the mucosa or submucosa.

Adult↗

PubMed1995

An improved source of bryostatin 10, Bugula neritina from the Gulf of Aomori, Japan.

Bryostatins have been isolated from diverse Japanese coastal specimens of Bugula neritina guided by inhibitory activity against fertilized sea urchin egg cell division. B. neritina from the Gulf of Aomori, Japan, has been found to contain bryostatin 10 [1b] in high yield (10(-3)%) for this class of compounds. The 1H- and 13C-nmr signals of bryostatin 10 [1b] were reassigned by 2D nmr techniques. The conformation of bryostatin 10 [1b] in solution was revealed by nmr studies. This compound also exhibited activity in a steroidogenesis assay by increasing the production of adrenocortical hormones nearly twofold.

Animals↗

PubMed1995

Beta-sarcoglycan (A3b) mutations cause autosomal recessive muscular dystrophy with loss of the sarcoglycan complex.

The dystrophin associated proteins (DAPs) are good candidates for harboring primary mutations in the genetically heterogeneous autosomal recessive muscular dystrophies (ARMD). The transmembrane components of the DAPs can be separated into the dystroglycan and the sarcoglycan complexes. Here we report the isolation of cDNAs encoding the 43 kD sarcoglycan protein beta-sarcoglycan (A3b) and the localization of the human gene to chromosome 4q12. We describe a young girl with ARMD with truncating mutations on both alleles. Immunostaining of her muscle biopsy shows specific loss of the components of the sarcoglycan complex (beta-sarcoglycan, alpha-sarcoglycan (adhalin), and 35 kD sarcoglycan). Thus secondary destabilization of the sarcoglycan complex may be an important pathophysiological event in ARMD.

Amino Acid Sequence↗

PubMed1995

Neuropathy target esterase of hen brain: active site reactions with 2-[octyl-3H]octyl-4H-1,3,2-benzodioxaphosphorin 2-oxide and 2-octyl-4H-1,3,2-[aryl-3H]benzodioxaphosphorin 2-oxide.

2-Octyl-4H-1,3,2-benzodioxaphosphorin 2-oxide (octyl-BDPO) is one of the most potent inhibitors known for neuropathy target esterase (NTE) of hen brain with 50% inhibition at 0.2 nM. Two NTE-like proteins, i.e., resistant to paraoxon and sensitive to mipafox, of approximately 155 and approximately 119 kDa (designated NTE-155 and NTE-119, respectively) are labeled by [octyl-3H]octyl-BDPO and separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Labeling with [aryl-3H]octyl-BDPO is only approximately 15% of that with [octyl-3H]octyl-BDPO, indicating that the majority of the phosphorylated NTE undergoes aging with only a small proportion of nonaged target or intramolecular group transfer ("alkylation"). NTE-155 and NTE-119 have the same kinetic constants and maximal number of phosphorylation sites, equivalent for each of them to 26 fmol/mg of protein and totaling at least 0.44-1.2 micrograms of NTE protein/g of brain. Structure-activity investigations involving 17 combinations of organophosphorus (OP) compounds of varied chemical type, stereochemistry, and concentration establish an excellent correlation (r = 0.95) between inhibition of NTE activity and protein labeling and thereby the toxicological relevance of these assays, which equally implicate NTE-155 and NTE-119 (probably an autolysis product of NTE-155) as target in OP-induced delayed neuropathy. [octyl-3H]-Octyl-BDPO is an improved probe for NTE in terms of its potency, reactivity, selectivity, and the formation of 3H-labeled NTE with a stable phosphorus-carbon bond.

Animals↗

PubMed1995

A useful testing strategy in phase III trials: combined test of superiority and test of equivalence.

A useful testing strategy is proposed for a confirmatory phase III clinical trial. It consists of a combined test of superiority and test of equivalence, and it is easy to apply. By introducing the strategy, we can perform a post hoc analysis in a confirmatory experiment. Thus a more flexible decision will be possible than the usual single testing method provides. It is shown that the procedure needs no adjustment for multiplicity from the point of view of the closed testing procedure. The relationship between this strategy and a confidence interval is also discussed.

Clinical Trials, Phase III as Topic↗

PubMed1995

Mammalian alpha 1- and beta 1-syntrophin bind to the alternative splice-prone region of the dystrophin COOH terminus.

The carboxy-terminal region of dystrophin has been suggested to be crucially important for its function to prevent muscle degeneration. We have previously shown that this region is the locus that interacts with the sarcolemmal glycoprotein complex, which mediates membrane anchoring of dystrophin, as well as with the cytoplasmic peripheral membrane protein, A0 and beta 1-syntrophin (Suzuki, A., M. Yoshida, K. Hayashi, Y. Mizuno, Y. Hagiwara, and E. Ozawa. 1994. Eur. J. Biochem. 220:283-292). In this work, by using the overlay assay technique developed previously, we further analyzed the dystrophin-syntrophin/A0 interaction. Two forms of mammalian syntrophin, alpha 1- and beta 1-syntrophin, were found to bind to very close but discrete regions on the dystrophin molecule. Their binding sites are located at the vicinity of the glycoprotein-binding site, and correspond to the amino acid residues encoded by exons 73-74 which are alternatively spliced out in some isoforms. This suggests that the function of syntrophin is tightly linked to the functional diversity among dystrophin isoforms. Pathologically, it is important that the binding site for alpha 1-syntrophin, which is predominantly expressed in skeletal muscle, coincides with the region whose deletion was suggested to result in a severe phenotype. In addition, A0, a minor component of dystrophin-associated proteins with a molecular mass of 94 kD which is immunochemically related to syntrophin, binds to the same site as beta 1-syntrophin. Finally, based on our accumulated evidence, we propose a revised model of the domain organization of dystrophin from the view point of protein-protein interactions.

Alternative Splicing↗

PubMed1995

Inhibition of vitamin D3-induced cell differentiation by interferon-gamma in HL-60 cells determined by a nitroblue tetrazolium reduction test.

The combined effects of 1 alpha,25-dihydroxyvitamin D3 [1,25(OH)2D3] and interferon-gamma (IFN-gamma) or tumor necrosis factor alpha (TNF-alpha) on cell differentiation in HL-60 human promyelocytic leukemia cells were examined by a nitroblue tetrazolium (NBT) reduction test. 1,25(OH)2D3 at the concentrations of 7-70 nM induced NBT-positive cells, which was used as a criterion of cell differentiation. IFN-gamma itself showed little effect on induction of NBT-positive cells or on cell growth at a concentration up to 1000 U/ml. However, in a combination of 1,25(OH)2D3 with IFN-gamma (100 and 300 U/ml), cell differentiation was strongly inhibited and was accompanied by growth inhibition. Treatment with a combination of 1,25(OH)2D3 and TNF-alpha or IFN-gamma and TNF-alpha showed an additive effect on cell differentiation. IFN-gamma seems to act as a specific inhibitor for 1,25(OH)2D3-induced cell differentiation. To elucidate the cause of the inhibition of cell differentiation by IFN-gamma, the ability of the cells to produce superoxide (O2-) was examined after culture for 5 days in the presence of 1,25(OH)2D3 and IFN-gamma. The results indicated that the inhibition of IFN-gamma was caused by a reduction in the ability of the cells to produce O2- in response to stimulation by 12-O-tetradecanoylphorbol-13-acetate (TPA).

Calcitriol↗

PubMed1995

Dystrophin-associated proteins in muscular dystrophy.

Dystrophin-associated proteins (DAPs) are classified into a few groups, namely, those comprising of dystroglycan complex, sarcoglycan complex, syntrophin complex and others. Subsarcolemmal actin filaments are connected to laminin in the basement membrane through dystrophin and the dystroglycan complex. This system may function to protect muscle fibers from mechanical damage. Furthermore, the sarcoglycan complex is associated with the system. Defects in the components of the protection system or the sarcoglycan complex or both are characteristically found in various muscular dystrophies. The roles of the syntrophin complex are meagerly understood. In this review, the possible roles of laminin, DAPs and dystrophin in each dystrophy are explained.

Dystrophin↗

PubMed1995

Identification of transcriptional activation domain of TREB5, a CREB/ATF family protein that binds to HTLV-1 enhancer.

TREB5 (hXBP-1) protein is a transcription factor that recognizes the CRE-like element in enhancers of human T-cell leukemia virus and MHC class II gene and activates their transcription. TREB5 is a member of the CREB/ATF family, containing a basic amino acid region and leucine zipper structure (b-Zip structure). To characterize the key domain of TREB5 for transcriptional activation, mutational analysis was carried out. The C-terminal region of 148-221 amino acids was identified as an activation domain and was also active when fused to Gal4 DNA binding domain. This domain contains three unique regions rich in glutamic acid, glutamine, or serine/threonine and is active in both osteosarcoma (HOS) and T (Jurkat) cell lines. All of these three regions are essential; however, a part of the serine/threonine region was dispensable in Jurkat, but not in HOS cells. In addition to the activation domain, the N-terminal region showed activity in conjunction with the b-Zip structure, but not with the Gal4 DNA binding domain. Furthermore, this region showed activity in Jurkat cells, but not in HOS cells. These results suggest that TREB5 has two activational functions in transcription and may provide diversity in cell-type-specific transcriptional activation, possibly through dimerization with other b-Zip proteins and phosphorylation.

Amino Acid Sequence↗