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Biomedical subjects

T Shibata

Publications and source records attributed to T Shibata.

At least 433 records · Page 24Linked to original sources
PubMed1996

[Studies on "Fast Green FCF Standard" for the dye standard on the National Institute of Health Sciences].

The raw material for Fast Green FCF was tested for preparation of the "Fast Green FCF Standard (C.I. 42053)". Analytical data obtained were as follows: paper chromatography, only one spot is observed; arsenic content, 0.38 microgram/g; chloride content, 0.11%; sulfate content, 3.30%; heavy metals, lead, 8.0 micrograms/g, manganese, 28.1 micrograms/g, and chromium, 1.6 micrograms/g; infrared spectra, 1575 cm-1, 1169 cm-1, and 1033 cm-1; loss on drying, 2.39%; assay, 93.0% by the titanium trichloride titration. Based on the above results, the raw material was authorized as the Dye Standard of National Institute of Health Sciences.

Coloring Agents↗
PubMed1996

Membrane currents of murine osteoclasts generated from bone marrow/stromal cell co-culture.

Whole cell clamp recordings were conducted to examine the general behavior of ion channels in osteoclasts which were generated from bone marrow/stromal cell co-culture. In the resting state, inwardly and outwardly rectifying (IR and OR) currents were observed in the osteoclasts cultured for 5-18 days and the whole cell currents were classified into three types according to the conductance ratio between the OR and IR currents, such as, the IR type (OR/IR conductance < or = 0.2), the IR-OR type (0.2 < OR/IR < or = 5), and the OR type (OR/IR > 5). The IR type was found in 73% of cells (n = 78), the IR-OR type in 26% and the OR type in 1%. No relation was found between the current types and the number of nuclei or cultured days. The conductances varied among cells, but the IR conductance was larger than the OR conductance. The IR current was characterized by voltage-dependent kinetics, a negative conductance region and Ba(2+)-sensitivity. The reversal potential depended on the extracellular K+ concentration, indicating that K+ mediates the IR current. On the other hand, the OR current was reversibly reduced by decreasing extracellular Cl- concentration but not affected by K+, suggesting that the OR current depends on Cl-. High intracellular Ca2+ (1-10 microM) transiently activated a different class of outward current. These electrophysiological features resemble those in freshly isolated osteoclasts. We suggest that the ion channels involved in osteoclastic functions are expressed in the in vitro-generated osteoclasts and that the channels develop early in differentiation and are maintained for at least up to 18 days. Thus the co-culture system provide a useful model to examine roles of ion channels in osteoclastic functions.

Animals↗
PubMed1996

[Primary right atrial hemangiosarcoma manifesting as cardiac tamponade: a case report with transesophageal echocardiography].

A 39-year-old woman presented with a right atrial hemangiosarcoma manifesting as cardiac tamponade with complaints of chest discomfort and dyspnea. Transthoracic echocardiography revealed remarkable pericardial effusion and a right atrial mass. Transesophageal echocardiography disclosed the tumor extending into the right atrial cavity. Surgery found the tumor was poorly demarcated, immobile and adhered to the adjacent right atrial wall and septum. The echocardiographic findings correlated well with the surgical and autopsy findings.

Adult↗
PubMed1996

[Myopericarditis].

Explore the source record for details and available documents.

Diagnosis, Differential↗
PubMed1995

Identification of the coding region of Saccharomyces cerevisiae chromosome VI using the computer program GenMark.

We searched the nucleotide sequence of budding yeast Saccharomyces cerevisiae chromosome VI (270 kb) for candidate coding regions, using the computer program GenMark. One hundred and twenty-nine putative genes were identified, which is almost the same as the number of ORFs on this chromosome. Nineteen new putative genes were identified through the GenMark analysis. Most large ORFs were also correctly identified (87% of the predicted putative genes identified by the GenMark (110 of 127) matched the reported ORFs). The new coding regions were mostly small but they were distinguished from the more than 2000 ORFs identified by Genetyx. GenMark did not predict 17 ORFs that were over 300 bp long. As these ORFs include known genes, their sequence context may differ somewhat from that of typical yeast genes. These analyses revealed the high potential of GenMark to identify putative genes from numerous short ORFs and will produce information on the likelihood of their being actual genes.

Base Sequence↗
PubMed1995

Cloning and sequencing of the chaperonin-encoding Cctd gene from Fugu rubripes rubripes.

CCT, a chaperonin containing t-complex polypeptide 1 (TCP-1), is a cytosolic molecular chaperone involved in the folding of proteins. We have isolated the Cctd gene from a Fugu rubripes rubripes (Frr) genomic library using a rat Ccta cDNA as a probe, and cloned its cDNA by reverse transcription-polymerase chain reaction (RT-PCR) using a pair of oligodeoxyribonucleotides corresponding to the 5' and 3' non-coding regions of Frr Cctd. Cctd spans a region of 4.7 kb and consists of at least 13 exons with small introns of about 144 bp on average. The Cctd cDNA sequence revealed a deduced polypeptide of 536 amino acids sharing a high degree of homology with that of the mouse Cctd cDNA (88%). Cctd is present as a single-copy gene, as shown by genomic Southern blot analysis, and can be used for evolutionary and classification analyses of Fugu species.

Amino Acid Sequence↗
PubMed1995

Atlanto-occipital hypermobility in subjects with Down's syndrome.

STUDY DESIGN: The upper cervical spines of 57 subjects with Down's syndrome were retrospectively examined, with special attention to atlanto-occipital mobility. OBJECTIVE: To examine the magnitude of atlanto-occipital mobility and its clinical significance in subjects with Down's syndrome. SUMMARY OF BACKGROUND DATA: Atlanto-occipital translation of more than 1 mm in adults implies instability. However, the normal value in children with Down's syndrome has not been established, and the value in Down's syndrome has not been evaluated based on a comparison between subjects with Down's syndrome and control subjects. METHODS: Measurements were made by Wiesel and Rothman's method in 38 subjects with Down's syndrome and 34 control subjects. RESULTS: Atlanto-occipital translation in the Down's syndrome group ranged from 0-6.4 mm (mean, 2.3 mm), whereas in the control group it ranged from 0-2.1 mm (mean, 0.61 mm). The difference was statistically significant. Of the 38 subjects with Down's syndrome, 37 were asymptomatic. CONCLUSION: The magnitude of atlanto-occipital translation, as expected, apparently was greater in subjects with Down's syndrome than in control subjects. Although the possibility of neurologic complications should be considered whenever unusually high atlanto-occipital mobility is seen, a majority of the subjects with Down's syndrome were asymptomatic.

Adolescent↗
PubMed1995

GAPO syndrome: report on the first case in Japan.

We studied a 3.5-year-old Japanese boy with growth retardation, alopecia, pseudoanodontia, and bilateral papilledema. He was born of nonconsanguineous parents, but his paternal grandparents were related. From his characteristic physical manifestations, we diagnosed him as the first known case of GAPO syndrome in Japan and perhaps in the Mongoloid race. Our case had prominent dilatation of scalp veins and an audible intracranial bruit. Cranial angiography documented a narrowing of the sigmoid sinuses, with no flow to either jugular vein. We discuss here the relationships between optic atrophy and intracranial vascular changes in this syndrome.

Abnormalities, Multiple↗
PubMed1995

Optical isomers of a new 2-nitroimidazole nucleoside analog (PR-350 series): radiosensitization efficiency and toxicity.

PURPOSE: A new 2-nitroimidazole nucleoside radiosensitizer, PR-350 (1-[1',3',4'-trihydroxy-2'-butoxy]-methyl-2-nitroimidazole), has been reported to be as efficient as and less toxic than etanidazole. This compound is racemic, and it was recently optically resolved into two isomers, PR-68 (2'R,3'S type) and PR-69 (2'S,3'R type). The other two isomers, PR-28 (2'S,3'S type) and PR-44 (2'R,3'R type), were asymmetrically synthesized. In the present study, we investigated the properties, sensitizing activity, and toxicity of PR-350 and the four optical isomers in comparison with those of other 2-nitroimidazole hypoxic cell radiosensitizers, etanidazole, KU-2285, KIN-804, and RP-170. Because PR-350 and PR-28 can be industrially synthesized, we evaluated whether either of these two drugs are suitable for further investigation. METHODS AND MATERIALS: In an in vitro study, EMT-6 cells were irradiated at a dose of 1-3 Gy under hypoxic conditions in the presence of the drugs at a concentration of 1 mM. A combined cytokinesis-block micronucleus and chromosomal aberration assay was performed. To assess the in vivo effects, colony assay and growth delay assay were performing using SCCVII tumor-bearing C3H mice. The mice received 16-24 GY 10-40 min after administration of 50-200 mg/kg of the drugs. Toxicity and pharmacokinetics in mice were also investigated. RESULTS: The sensitizer enhancement ratio (SER) in the in vitro cytokinesis-block micronucleus assay increased in the following order: PR-69 (1.27) approximately equal to PR-28 (1.31) approximately equal to PR-44 (1.38) approximately equal to PR-350 (1.41) approximately equal to PR-68 (1.47) < etanidazole (1.79) < KIN-804 (2.03) approximately equal to KU-2285 (2.30). The SER at a dose of 200 mg/kg and at an interval of 20 min (optimal interval) in the in vivo-in vitro colony assay increased as follows: PR-44 (1.26) approximately equal to PR-28 (1.29) < PR-69 (1.34) approximately equal to etanidazole (1.35) approximately equal to PR-350 (1.36) < RP-170 (1.41) approximately equal to PR-68 (1.41) < KU-2285 (1.49). The growth delay assay also showed that PR-350 was less efficient than KU-2285 and more efficient than PR-28. PR-350 and the four isomers had similar reduction potentials, but PR-28 and PR-44 were more hydrophilic than PR-68 and PR-69. The LD50 in mice were 5.8 g/kg for PR-350, approximately 7 g/kg for PR-28, 4 g/kg for PR-68, and 6 g/kg for PR-44 and PR-69. The concentration of PR-28 in the murine sciatic nerve was lower than that of PR-350. CONCLUSION: In vivo radiosensitizing activity differed among the four optical isomers, which appeared to be due, at least in part, to differences in lipophilicity. Although PR-28 was the least toxic, its low sensitization efficiency does not warrant clinical trials. Among the PR compounds, PR-68 appears to be most efficient, but optical resolution of PR-68 from PR-350 is expensive, and asymmetrical synthesis of PR-68 is not established. Therefore, PR-350 seems to be most suitable for further investigation among the PR-350 series compounds, considering its higher efficiency compared with PR-28 and PR-44, and established synthesis.

Animals↗
PubMed1995

A nuclear mutation defective in mitochondrial recombination in yeast.

Homologous recombination (crossing over and gene conversion) is generally essential for heritage and DNA repair, and occasionally causes DNA aberrations, in nuclei of eukaryotes. However, little is known about the roles of homologous recombination in the inheritance and stability of mitochondrial DNA which is continuously damaged by reactive oxygen species, by-products of respiration. Here, we report the first example of a nuclear recessive mutation which suggests an essential role for homologous recombination in the stable inheritance of mitochondrial DNA. For the detection of this class of mutants, we devised a novel procedure, 'mitochondrial crossing in haploid', which has enabled us to examine many mutant clones. Using this procedure, we examined mutants of Saccharomyces cerevisiae that showed an elevated UV induction of respiration-deficient mutations. We obtained a mutant that was defective in both the omega-intron homing and Endo.SceI-induced homologous gene conversion. We found that the mutant cells are temperature sensitive in the maintenance of mitochondrial DNA. A tetrad analysis indicated that elevated UV induction of respiration-deficient mutations, recombination deficiency and temperature sensitivity are all caused by a single nuclear mutation (mhr1) on chromosome XII. The pleiotropic characteristics of the mutant suggest an essential role for the MHR1 gene in DNA repair, recombination and the maintenance of DNA in mitochondria.

Base Sequence↗
PubMed1995

Assignment of the 49-kDa (PRIM1) and 58-kDa (PRIM2A and PRIM2B) subunit genes of the human DNA primase to chromosome bands 1q44 and 6p11.1-p12.

DNA primase is an essential replication protein that catalyzes the synthesis of oligoribonucleotide primers. DNA primase, consisting of two subunits (p49 and p58), plays a key role in both the initiation of DNA replication and the synthesis of Okazaki fragments for lagging strand synthesis. We mapped the locations of human chromosomes of the genes coding for both subunits [p49 (PRIM1) and p58 (PRIM2)] by PCR amplification using DNAs of a panel of somatic hybrids, to chromosomes 1 and 6, respectively. The PRIM1 gene was mapped to 1q44, and two PRIM2 loci (PRIM2A and PRIM2B) were detected at 6p11.1-p12 by fluorescence in situ hybridization using several genomic DNA probes.

Animals↗
PubMed1995

Effects of complement activation on the expression of CD59 by human mesangial cells.

Human mesangial cells (HMC) were analyzed for their expression of 20-kDa homologous restriction factor (CD59), a glycophospholipid-anchored regulatory protein of the complement cascade. Flow cytometric analysis showed that CD59 was expressed on the HMC membrane and, following the activation of the terminal pathway complement components, CD59 expression on the HMC membrane increased. Northern blot analysis showed that CD59 mRNA levels increased by complement activation. Of interest, CD59 mRNA levels increased by soluble complement activation product, zymosan-activated C8-depleted serum, but not zymosan-activated C5-depleted serum. This effect of soluble complement activation product was due to the presence of the action of C5a. Thus, recombinant C5a increased CD59 mRNA levels. The capacity of CD59 to reinsert into rat E and inhibit C-mediated lysis was inhibited by mAb against CD59 (1F5). Metabolic labeling using [35S]cysteine showed that the molecular mass of CD59 in HMC was 20 kDa. In conclusion, CD59 is present on HMC and the expression of CD59 is controlled by at least two steps of complement activation pathway, C5 and C8.

Antigen-Antibody Complex↗
PubMed1995

Depletion of small cytoplasmic RNA confers fusidic-acid resistance on Bacillus subtilis.

Bacillus subtilis small cytoplasmic RNA (scRNA) is a member of a signal recognition particle (SRP)-like RNA family. To analyze the function of scRNA in protein synthesis, a B. subtilis strain SC201NA was constructed in which the expression of intact scRNA is regulated by an IPTG-inducible promoter. In this strain, depletion of scRNA leads to deficient translation and sporulation as well as morphological changes. In addition, the growth of SC201NA in the absence of IPTG became fusidic-acid resistant. The acquisition of fusidic-acid resistant phenotype by depletion of scRNA suggested that scRNA is associated with elongation factor G (EF-G) in the translation process.

Bacillus subtilis↗
PubMed1995

c-erbB-2 gene product directly associates with beta-catenin and plakoglobin.

Association of the c-erbB-2 oncogene product with the cadherin-catenin complex has been demonstrated in human cancer cell lines. Although beta-catenin and plakoglobin have been proven to be crucial for the association, no previous study has shown whether the interactions are direct or indirect. In the present study, the c-erbB-2 gene product was shown by far-Western blotting analysis to associate directly with both beta-catenin and plakoglobin through its cytoplasmic domain core region, which showed extensive homology with epidermal growth factor receptor. These data suggest that c-erbB-2-induced signaling is also directly liked to the cadherin-mediated cell adhesion and "invasion-suppressor" system through beta-catenin and plakoglobin in cancers.

Adenocarcinoma↗
PubMed1995

High-performance liquid-chromatographic analysis of dopachrome and dihydroxyphenylalanine.

A high-performance liquid-chromatographic system for the determination of dopachrome and dihydroxy-phenylalanine (dopa) is described. The retention of dopa and dopachrome on C18 reversed-phase columns was investigated as a function of pH in the mobile phase, and as expected the capacity factors were found to be pH dependent. The chromatographic behavior is explained by the change in net charge and polarity of dopachrome and dopa when pH varies. Satisfactory separation of dopachrome and dopa was obtained. An advantage of the method is that the measurements of dopachrome stability and disappearance are uninfluenced by concomitant formation of melanochromes which, however, is the case when the disappearance is followed by measurement of the decrease in absorbance at 475 nm. The utility of the method is illustrated by following the disappearance of dopachrome as a measure of dopachrome tautomerase activity.

Animals↗
PubMed1995

Sequencing of an 18.8 kb fragment from Saccharomyces cerevisiae chromosome VI.

The nucleotide sequence of lambda phage clone 4121, which contains the 18.8 kb fragment of Saccharomyces cerevisiae chromosome VI left arm, was determined. This sequence had seven open reading frames (ORFs), four of which were identical to known genes (ACT1, YPT1, TUB2 and RPO41). Another three ORFs (4121orfR003, 4121orfR004 and 4121orfRN001) were highly homologous to FET3 multi-copper oxidase, glucose transport protein, and hypothetical protein of YIL106w on chromosome IX, respectively. 4121orfRN01 is suggested to contain an intron.

Amino Acid Sequence↗