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T Miyazawa

Publications and source records attributed to T Miyazawa.

At least 343 records · Page 19Linked to original sources
PubMed1992

Chemiluminescent simultaneous determination of phosphatidylcholine hydroperoxide and phosphatidylethanolamine hydroperoxide in the liver and brain of the rat.

The quantification of phospholipid hydroperoxides in biological tissues is important in order to know the degree of peroxidative damage of membrane lipids. For this purpose, optimal conditions for the chemiluminescent simultaneous assay of phosphatidylcholine hydroperoxide (PCOOH) and phosphatidylethanolamine hydroperoxide (PEOOH) in rat liver and brain were determined. A chemiluminescence detection-high performance liquid chromatography (CL-HPLC) method that incorporates cytochrome c and luminol as a post-column hydroperoxide-specific luminescent reagent was used (Miyazawa et al. 1987. Anal. Lett. 20: 915-925; Miyazawa. 1989. Free Radical Biol. Med. 7: 209-217). An n-propylamine-bound silica column with hexane-2-propanol-methanol-water 5:7:2:1 (v/v/v/v) (flow rate 1.0 ml/min) as eluant was used to determine both PCOOH and PEOOH, which were separated from each other and from other lipids and lipid-soluble antioxidants. High reproducibility and sensitivity as low as 10 pmol hydroperoxide-O2 were observed with a mixture of 10 micrograms/ml cytochrome c and 2 micrograms/ml luminol in 50 mM borate buffer (pH 10.0, flow rate 1.1 ml/min) as luminescent reagent and a post-column mixing joint temperature of 40 degrees C. Using the established analytical conditions, it was confirmed that both PCOOH (1324 +/- 122 pmol/g liver, 114 +/- 18 pmol/g brain, mean +/- SD) and PEOOH (728 +/- 89 pmol/g liver, 349 +/- 60 pmol/g brain, mean +/- SD) are present in the liver and brain of Sprague-Dawley rats bred on a slightly modified AIN-76A semisynthetic diet for 3 months. The phospholipid hydroperoxide content in the rat liver was shown to be affected by dietary oils, but not significantly affected in the brain.

Animals↗
PubMed1992

[Quantitative fluorescence-immunohistochemistry of presynaptic terminals using a monoclonal antibody against a synaptic vesicle-specific protein (SVP-38) in paraffin sections].

We developed a method for investigating impairment of synaptogenesis quantitatively involving measurement of the fluorescence intensity emitted by immunohistochemically stained paraffin sections of rat brain using a monoclonal antibody (Mab 171B5) against a synaptic vesicle protein (SVP-38). We applied this method to congenitally hydrocephalic and non-hydrocephalic brains of HTX-rats, and compared the postnatal changes in the fluorescence intensity in the molecular layer of the cerebral cortex. In non-hydrocephalic HTX-rats, the fluorescence intensity remained nearly unchanged from the 1st to 7th postnatal day and then increased at an almost linear rate until the 21st postnatal day, when it reached 4.5 times the value on the 7th postnatal day. The increase thereafter was gradual until the 28th postnatal day. In hydrocephalic HTX-rats, the fluorescence intensity showed a marked reduction on the 28th postnatal day (p < 0.01). This finding indicated impairment of synaptogenesis. We believe that this method provides useful information for evaluating the impairment of synaptogenesis in various pathological conditions in mammarian brains. The basic aspects of this method which support its validity are also discussed.

Animals↗
PubMed1992

A cDNA encoding feline CD4 has a unique repeat sequence downstream of the V-like region.

We have cloned, sequenced and expressed a cDNA encoding the feline CD4 glycoprotein. This clone, termed FT121, contains a unique repeat sequence downstream of the V-like region which has not been reported in other mammalian CD4 cDNA. In addition, the cysteine residues at positions 45 and 175 have an unusual pattern. On the other hand, regions other than the unique sequence share significant homology with human CD4 and mouse L3T4 cDNA in the amino acid sequence deduced from the nucleotide sequence, especially in the putative cytoplasmic region. Here, we show that FT121 has a complete open reading frame and efficiently expresses feline CD4 molecules on COS cells. Further we found that the cytoplasmic components, lymphocyte-specific protein-tyrosine kinase p56lck binding sites and phosphorylation site (serine resides), are well conserved, though the extracellular region of the feline CD4 molecule deduced from FT121 is probably different from that of human CD4 and mouse L3T4.

Amino Acid Sequence↗
PubMed1992

[Alloprotein].

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Amino Acid Sequence↗
PubMed1991

Methionyl-tRNA synthetase gene from an extreme thermophile, Thermus thermophilus HB8. Molecular cloning, primary-structure analysis, expression in Escherichia coli, and site-directed mutagenesis.

The gene for the methionyl-tRNA synthetase (MetRS) from an extreme thermophile, Thermus thermophilus HB8, was cloned and sequenced. By expression of the T. thermophilus MetRS gene in Escherichia coli cells, thermostable MetRS was overproduced and purified to homogeneity by heat treatment and one-step column chromatography. The amino acid sequence of T. thermophilus MetRS showed low identities (approximately 25%) with those of MetRSs from E. coli, and cytoplasm and mitochondria of Saccharomyces cerevisiae. However, the amino acid residues in the binding sites for ATP and the anticodon and the 3' terminus of tRNA(Met) are highly conserved among the four MetRSs. T. thermophilus MetRS has a zinc finger-like sequence with all the three cysteine residues and a histidine residue. By site-directed mutagenesis of one of the cysteine residues (Cys127) of T. thermophilus MetRS, the SH group was found to be important for methionyl-tRNA synthesis. Just upstream of the structural gene for T. thermophilus MetRS there is a short open reading frame which codes for a methionine-rich peptide and is partly overlapped with an alternative terminator/antiterminator structure, suggesting that transcription of this gene is regulated by attenuation. Further upstream a region contains a nucleotide sequence homologous to that of the 5' half of T. thermophilus initiator tRNA(Met).

Amino Acid Sequence↗
PubMed1991

Comparison of retinal nerve-fiber layer in high- and normal-tension glaucoma.

In all, 20 eyes of 20 normal-tension glaucoma (NTG) patients and 20 eyes of high-tension glaucoma (HTG) patients matched for similar visual field defects underwent retinal nerve-fiber-layer (RNFL) analysis using a computerized digital-image analysis system. Subjects with NTG showed more localized RNFL loss than diffuse loss as compared with HTG patients. The results support the hypothesis that there may be different mechanisms of damage in glaucoma.

Adult↗
PubMed1991

Learning disability and impairment of synaptogenesis in HTX-rats with arrested shunt-dependent hydrocephalus.

Using HTX-rats with congenital hereditary hydrocephalus, we used neuropathological methods, including quantitative Golgi study and neurobehavioral evaluation, to investigate the following problems. (1) What kind of damage does congenital hydrocephalus cause to developing brain tissue? (2) How much can the damage be repaired by ventriculoperitoneal shunting if performed at 4 weeks of age, enabling 4-week-old hydrocephalic rats to survive beyond sexual maturation? (3) What is the status of learning ability of long-term surviving rats with arrested shunt-dependent hydrocephalus? The findings of our study suggest that congenital hydrocephalus impairs the development and formation of the dendrites and spines of the cerebrocortical neurons. Following ventriculoperitoneal shunting, we confirmed that rats with arrested shunt-dependent hydrocephalus demonstrated learning disability in a light-darkness discrimination test using a Y-maze. The development of the dendrites and spines of the cerebrocortical neurons seemed to take place to some degree after shunting, but normal spine density could not be restored. Also suggested was a possible relationship between learning disability and a decrease in spine density, i.e., impairment of synaptogenesis.

Animals↗
PubMed1991

Possible essentially of docosahexaenoic acid in Japanese monkey neonates: occurrence in colostrum and low biosynthetic capacity in neonate brains.

The importance of mother's milk as a source of docosahexaenoic acid (DHA) in Japanese monkey neonates was investigated. The DHA content in monkey colostrum total lipids was 2.2%, similar to or slightly higher than in humans. A comparison of the biosynthetic capacity of brain microsomes from monkeys of different age (up to 10 years) showed that chain elongation/desaturation of linolenic acid and eicosapentaenoic acid in neonates was significantly less pronounced than in adults. In particular, the formation of DHA, which is the product of delta 4 desaturase, was negligible. These results suggest that milk is an important source of DHA in Japanese monkey neonates.

Aging↗
PubMed1991

Low-level chemiluminescence from Drosophila melanogaster fed with chemical mutagens polycyclic aromatic hydrocarbon quinones and a carcinogenic bracken fern.

The spontaneous photon emission (chemiluminescence) from Drosophila melanogaster fed chemical mutagens, polycyclic aromatic hydrocarbon quinones, and a carcinogenic bracken fern was studied. The fly chemiluminescence was evidently enhanced by mutagen or carcinogen administration and was increased proportionally to the administered amount of tested compound. Strong chemiluminescence was observed especially at the larval stage. Living larvae emitted stronger chemiluminescence than their homogenate. The chemiluminescence from Drosophila melanogaster fed polycyclic aromatic hydrocarbon quinones showed a linear relation with the mutation frequency in the Drosophila wing spot test. The chemiluminescence from flies fed a bracken fern decreased by the addition of free radical scavengers and active oxygen quenchers. The phosphatidylcholine hydroperoxide concentration in the flies was increased proportionally with the chemiluminescence intensity. It seems that the free radical formation is stimulated as shown by the enhanced chemiluminescence in mutagen- or carcinogen-dosed flies, and as a result, lipid peroxide accumulation accompanies mutation in Drosophila melanogaster.

Animals↗
PubMed1991

Activation of feline immunodeficiency virus long terminal repeat by feline herpesvirus type 1.

By transfection of a recombinant plasmid containing the feline immunodeficiency virus (FIV) long terminal repeat (LTR) linked to the chloramphenicol acetyltransferase (CAT) gene followed by infection of feline herpesvirus type 1 (FHV-1) into Crandell feline kidney cells and Felis catus whole fetus 4 cells, enhancement of CAT activity was demonstrated. Furthermore, individual feline T-lymphocytes were productively co-infected with both FIV and FHV-1 in vitro as determined by two-color immunofluorescence and electron microscopy analyses. These results revealed the transactivation of the FIV LTR by FHV-1 and the dual infection of T-lymphocytes with both viruses. The possibility that FHV-1 might be a cofactor which plays a role in the pathogenesis of FIV infection is discussed.

Animals↗
PubMed1991

Linear cutaneous neurilemmomas on the forehead.

A 35-year-old woman had had pruritic linearly arranged papules on the right side of her forehead for 17 years. A biopsy specimen from one of the papules showed the histopathological appearance of an intradermal plexiform neurilemmoma. No other features of systemic neurofibromatosis or neurilemmomatosis were detected. Neurilemmoma usually occurs as a solitary lesion in the subcutis and there are only few reports of such localized multiple intradermal neurilemmomas associated with neither neurofibromatosis nor neurilemmomatosis.

Adult↗
PubMed1991

Molecular cloning of a novel isolate of feline immunodeficiency virus biologically and genetically different from the original U.S. isolate.

The Japanese isolate (TM1 strain) of feline immunodeficiency virus (FIV) which replicates in a feline CD4 (fCD4)-positive lymphoblastoid cell line (MYA-1 cells) was molecularly cloned from extrachromosomal closed circular DNA. The restriction map of the clone, termed pFTM 191 complete genome (CG), showed a considerable difference from that of the U.S. isolate (Petaluma strain) of FIV. The sequence homology in the long terminal repeat between the TM1 and Petaluma strain was 82%. The pFTM 191 CG was biologically active after transfection into Crandell feline kidney cells which were permissive for replication of FIV Petaluma. However, the progeny virions could not reinfect fCD4-negative Crandell feline kidney cells but could infect fCD4-positive MYA-1 cells. When a specific-pathogen-free cat was inoculated with the virus derived from the pFTM 191 CG, the cat seroconverted within 8 weeks postinoculation and FIV was reisolated at 4, 8, and 20 weeks postinoculation. These results indicate the infectivity of the pFTM 191 CG in vivo.

Animals↗
PubMed1991

Identification of feline immunodeficiency virus rev gene activity.

We constructed 16 deletion mutants from an infectious molecular clone of feline immunodeficiency virus (FIV) and a reporter plasmid carrying the bacterial chloramphenicol acetyltransferase (CAT) gene to identify the rev transactivator activity of the virus. Cotransfections of various mutants and the rev reporter clone bearing a portion of FIV env in addition to the CAT gene revealed that the sequence important for the augmentation of CAT production was located in three separate parts of the virus genome. This enhancement was FIV specific in that the human retrovirus rev and rex gene products did not activate the reporter. The phenotypic properties of an FIV proviral mutant containing a small deletion in the genome were similar to those of rev mutants derived from primate immunodeficiency viruses. These results indicate that FIV, like the other lentiviruses, contains the rev gene in its genome.

Animals↗
PubMed1991

[Effect of lisuride on experimental cerebral infarction in rats].

Lisuride is an ergot derivative with central dopaminergic (D2 agonistic) and serotonergic (5-HT1A agonistic) activity. The effect of lisuride on experimental cerebral infarction in rats was investigated. Cerebral infarction was induced by intracarotid infusion of a 50-microliters mixture in which deformed and rigid red blood cells treated with hypertonic solution were contained. Lisuride or 0.9% NaCl was administered subcutaneously 30 min before induction of cerebral infarction. Lisuride (0.01 mg/kg) not only prolonged the survival time of the animals but also suppressed cerebral edema, increase in the electrolytes content and histological damage in the brain. These results suggest that lisuride has a protective effect against cerebral infarction.

Animals↗
PubMed1991

Relation between functions and conformational characteristics of modified nucleosides found in tRNAs.

Conformational characteristics of N4-acetyl-2'-O-methylcytidine (ac4Cm), 5-methyl-2'-O-methylcytidine (m5Cm) and N2-dimethyl-2'-O-methylguanosine (m2(2)Gm) found in tRNAs from extremely thermophilic archaebacteria were analyzed by proton NMR spectroscopy. The 2'-O-methylation of ac4C, m5C and m2(2)G was found to stabilize the C3'-endo form and therefore cause "conformational rigidity". In particular, the ac4Cm was found to be extremely rigid due to additive effects of the N4-acetylation and 2'-O-methylation. Therefore, tRNAs from the extremely thermophilic archaebacteria use the base modifications in combination with the 2'-O-methylation, resulting in stabilization of the A-type conformation at specific positions in the tRNAs even at very high temperatures. In contrast, mesophile tRNAs use for a given site only one of these ribose and base modifications each of which is effective enough by itself at ordinary temperatures. These findings are consistent with our previous findings that roles of a variety of post-transcriptional modifications are to regulate the conformational rigidity/flexibility which is essential for the tRNA functions.

Archaea↗
PubMed1991

[Balloon occlusion pulmonary angiography and anticoagulant-antithrombotic therapy in ARDS-associated pulmonary vascular thrombosis].

Balloon occlusion pulmonary angiography was used to assess the frequency of pulmonary vascular thrombosis in five patients suffering from ARDS of diverse causes. Pulmonary hypertension, elevated pulmonary vascular resistance and disseminated intravascular coagulation were observed in all patients. Pulmonary artery filling defects (PAFD) were found in four of five patients. The results suggest that PAFD can be detected in a large proportion of patients in ARDS. It was therefore speculated that the detection of PAFD is a sign of severe lung injury. Urokinase, heparin and protease inhibitor were infused to test the potential reversibility of pulmonary vascular thrombosis in four patients. After infusion, we found angiographic evidence of clearing of obstruction in arteries in three of four patients. We conclude that anticoagulant-antithrombotic therapy can improve hemodynamics in ARDS-associated pulmonary vascular thrombosis.

Adult↗