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Biomedical subjects

T Miyazawa

Publications and source records attributed to T Miyazawa.

At least 253 records · Page 14Linked to original sources
PubMed1994

Recognition of UUN codons by two leucine tRNA species from Escherichia coli.

Codon recognition by Escherichia coli tRNA(Leu)4 and tRNA(Leu)5 was investigated by analysis of the competition between two aminoacyl-tRNA species in an in vitro protein synthesis. Both tRNA species strictly obey the wobble rule when they are in competition with other tRNA species. This is probably due to the post-transcriptional modifications at the first position of the anticodon of these tRNA(Leu) species, supporting the proposal that the conformational rigidity of post-transcriptionally modified pyrimidine nucleotides guarantees the correct codon recognition.

Amino Acid Sequence↗
PubMed1994

Nucleotide sequence and characterization of the feline herpesvirus type 1 immediate early gene.

We report the nucleotide sequence of feline herpesvirus type 1 (FHV-1) immediate early (IE) gene encoding a homologue to the ICP4 protein of herpes simplex virus type 1 and its flanking sequences. When we examined the regulatory function of the FHV-1 IE gene product by using the transient transfection assay with an effector plasmid expressing the FHV-1 IE gene in combination with chimeric various promoter-chloramphenicol acetyltransferase reporter constructs, the product was able to transactivate a putative FHV-1 TK promoter, pseudorabies virus and equine herpesvirus type 1 ICP4 promoters, and human immunodeficiency virus (HIV) long terminal repeat (LTR) in Crandell feline kidney cells. Furthermore, the FHV-1 IE gene product could transactivate both feline immunodeficiency virus and HIV LTRs in SW480 cells but not in Felis catus whole fetus 4 cells.

Alphaherpesvirinae↗
PubMed1994

Early ventriculoperitoneal shunt--effects on learning ability and synaptogenesis of the brain in congenitally hydrocephalic HTX rats.

The learning ability of congenitally hydrocephalic HTX rats in which hydrocephalus had been arrested by the insertion of a V-P shunt 7 days after birth (early shunt) was assessed by means of the light-darkness discrimination test when the animals reached maturity. Early shunt placement resulted in marked reduction in size of abnormally enlarged ventricles and the prevention of both decreasing spine density and decay of synaptic vesicle protein (SVP-38) in the affected cerebral cortex. The learning ability of such animals was also found not to be impaired compared with that of animals in a sham-operation group. On the basis of these investigations, it is concluded that early shunt placement may have a beneficial role in preventing not only impairment of synaptogenesis of the brain by progressing hydrocephalus, but also learning disability. Recent biochemical investigation of the developing brains of hydrocephalic HTX rats revealed problems that cannot be resolved by early shunt insertion, and these are also discussed.

Animals↗
PubMed1994

Effects of insertion of multiple AP-1 binding sites into the U3 region of the long terminal repeat of feline immunodeficiency virus.

An oligonucleotide containing multiple AP-1 binding sites was introduced into the regulatory sequence in the long terminal repeat (LTR) of feline immunodeficiency virus (FIV). Chloramphenicol acetyltransferase assay revealed that basal promoter activity of the mutated LTR was higher than that of the wild-type LTR in Crandell feline kidney (CRFK) cells. The mutated LTR was introduced into an infectious molecular clone of FIV and the clone was transfected into CRFK cells. The virus production of the mutant in the cells was as high as that of the wild-type when determined by the reverse transcriptase activity assay. The growth of the mutant virus obtained from the transfected CRFK cells was examined in feline T lymphoblastoid cell lines (MYA-1 and FeL-039 cells) and primary feline peripheral blood mononuclear cells (fPBMCs). The growth was delayed when compared with that of the wild-type virus in all the cells used. Upon examination by polymerase chain reaction, the length of the LTR of the mutant virus was shortened in both MYA-1 cells and fPBMCs. Sequence analysis revealed that the insertion was completely deleted 39 days after infection in the MYA-1 cells.

Animals↗
PubMed1994

Induction of apoptosis in a T lymphoblastoid cell line infected with feline immunodeficiency virus.

The mechanism of cell death induced by feline immunodeficiency virus (FIV) infection was investigated in an interleukin 2(IL-2)-dependent T-lymphoblastoid cell line (MYA-1). DNA extracted from FIV-infected MYA-1 cells showed a ladder of nucleosomal DNA, indicating that the cytopathic effect (CPE) observed in these cells was due to apoptosis. Infection of MYA-1 cells with FIV was associated with suppression of the proliferative response of the cells to exogenous IL-2 prior to DNA fragmentation. These findings suggest that FIV-induced CPE in these T-lymphoblastoid cells is associated with apoptosis possibly due to a defect in the IL-2 signal transduction pathway.

Animals↗
PubMed1994

The genome of feline immunodeficiency virus.

Feline immunodeficiency virus (FIV) is a member of the genus Lentivirus of the family Retroviridae. FIV can infect T lymphocytes and monocytes/macrophages in vitro and in vivo, and causes an acquired immunodeficiency syndrome-like disease in cats. Several isolates of FIV from geographically distant countries have been molecularly cloned. There is considerable heterogeneity especially in Env gene among the FIV isolates and they can be divided into two or more subgroups. Like other lentiviruses, FIV has a complex genome structure. Gag gene encodes matrix, capsid and nucleocapsid proteins, and Pol gene encodes protease, reverse transcriptase, dUTPase and integrase. The dUTPase is not present in the primate lentiviruses but present in the non-primate lentiviruses. Env gene encodes surface and transmembrane envelope glycoproteins. In addition to the structural and enzymatic proteins, at least three more genes (Vif, ORF A, Rev) are present in FIV. Vif is related to the infectivity of the cell-free viruses. Rev functions in the stability and transport of incompletely spliced viral RNAs from the nucleus to cytoplasm and is indispensable for virus replication. Although the Tat protein of the primate lentiviruses is essential for virus replication, ORF A (putative Tat gene) of FIV is not essential for virus replication in established feline T lymphoblastoid cell lines. However, the ORF A gene product is related to the efficient replication of the virus in primary peripheral blood lymphocytes. In the long terminal repeat (LTR) of FIV, there are many putative binding sites for enhancer/promoter proteins. Among these binding sites, the putative AP-1 site is important for basal promoter activity of the LTR and responsible for the T cell activation signal through protein kinase C, however the site is not required for the virus replication in established feline T lymphoblastoid cell lines. Comparative study of the molecular biology of lentiviruses revealed that the genome structure, splicing pattern and functional enhancer protein-binding sites of FIV are more similar to those of the ruminant lentiviruses than those of the primate lentiviruses.

Animals↗
PubMed1994

Analysis of chromosome-sized DNA and genome typing of isolated strains of Taylorella equigenitalis.

Analysis of chromosome-sized DNA and genome typing of Taylorella equigenitalis NCTC11184, Kentucky 188, and five strains of T. equigenitalis isolated in Japan were carried out. The three restriction enzymes used, ApaI, NaeI and NotI, cleaved the genomic DNAs of five Japanese strains of T. equigenitalis into relatively limited numbers of restriction fragments, which were well resolved on crossed-field gel electrophoresis (CFGE). The respective profiles after CFGE of the restriction fragments from all five strains were essentially identical to each other after digestion by ApaI, NaeI or NotI. Hence it appears that these strains have a common genome type with respect to these three restriction enzymes. It was also shown that the respective profiles from these strains were essentially different from those of T. equigenitalis NCTC11184 and those of Kentucky 188 after digestion with ApaI, NaeI or NotI.

Animals↗
PubMed1994

Carrier-state infection of feline T-lymphoblastoid cells with feline calicivirus.

The susceptibility of feline T lymphocytes to feline calicivirus (FCV) in vitro was investigated using feline T-lymphoblastoid cell lines, namely MYA-1 and FL74 cells. The virus titers of supernatants in FCV-infected MYA-1 and FL74 cell cultures increased rapidly, and FCV antigens were also detected in the FCV-infected cells. There were slight differences in the molecular weights of capsid proteins expressed in FCV-infected MYA-1, FL74 and Crandell feline kidney cells. MYA-1 and FL74 cells were productively and persistently infected with FCV, and FCV antigens were observed in the FCV-infected cells for more than one month. At 3 months post infection, FCV-infected FL74 cells that stopped producing infectious FCV could be reinfected with FCV. However, no cytopathic effects were observed.

Animals↗
PubMed1994

Inhibition of feline immunodeficiency virus gene expression and replication by alphaherpesvirus ICP4 homologues.

We investigated the effects of pseudorabies virus (PRV), herpes simplex virus type 1 (HSV-1), and equine herpesvirus type 1 (EHV-1) ICP4 homologues on feline immunodeficiency virus (FIV) long terminal repeat (LTR)-directed gene expression. This was done by using the transient expression chloramphenicol acetyltransferase (CAT) assay in Crandell feline kidney (CRFK) and Felis catus whole fetus 4 cells transfected with a chimeric FIV LTR-CAT reporter construct in combination with effector plasmids expressing the PRV, HSV-1 or EHV-1 ICP4 homologue. The experiments demonstrated that the ICP4 homologues could significantly inhibit FIV LTR-directed gene expression. Moreover, the ICP4 homologues also exhibited a marked inhibitory effect on FIV replication in CRFK cells cotransfected with an infectious molecular clone of FIV.

Animals↗
PubMed1994

Comparison of biological properties of feline immunodeficiency virus isolates using recombinant chimeric viruses.

The biological properties of homogeneous populations of feline immunodeficiency viruses derived from infectious, molecular clones of the TM1, TM2 and Petaluma strains were compared. Differences in infectivity for Crandell feline kidney (CRFK) cells, and in syncytium formation and replication kinetics in a feline T lymphoblastoid cell line (MYA-1 cells) were observed. To investigate the basis of these differences between the TM2 and Petaluma strains, we first compared the basal promoter activity of the long terminal repeat which is a highly divergent region, but no significant difference in activities was found in CRFK cells. We then constructed two recombinant chimeric clones which carry gag, pol, vif, and ORF A from the heterologous virus. From analyses using the chimeric clones, it was revealed that efficient virus growth in CRFK cells and MYA-1 cells was regulated by the gag, pol, vif and ORF A regions, whereas viral determinants of infectivity for CRFK cells, and syncytium formation and cytopathogenicity in MYA-1 cells, were located in the env region.

Animals↗
PubMed1994

[A case report of psittacosis and chlamydial isolation from a patient].

A 48-year-old female was seen at our hospital after having a severe fever of nearly 40 degrees C, for a period of 9 days. She complained of pain in the left side of her chest. An X-ray examination revealed a slight infiltration of the upper and middle lung fields. At this time, it was learned that the women's pet bird had recently died. This case was diagnosed as acute pneumonia due to psittacosis. Therefore the administration of Roxithromycin was started. After a few day her condition improved. During the course of treatment, serum was taken and a throat swab was done. A micro-immunofluorescence (MIF) test was performed to check the serum antibody levels against Chlamydia psittaci. The serum titer rose from 1:8 to 1:256 in 15 days after admission. The final diagnosis was made after positive isolation of C. psittaci by means of the cell culture method.

Adult↗
PubMed1994

Changes of synapse-related proteins (SVP-38 and drebrins) during development of brain in congenitally hydrocephalic HTX rats with and without early placement of ventriculoperitoneal shunt.

Hydrocephalic and nonhydrocephalic HTX rats served, respectively, as experimental and sham operation animals. They were treated by insertion of ventriculoperitoneal (V-P) shunts at 7 days after birth (early shunt). Monoclonal antibodies against synaptic vesicle proteins (SVP-38) and developmentally regulated brain proteins (drebrins) were used to assess these two synapse-related proteins by means of either a quantitative immunohistochemical method or a qualitative immunoblot analysis. The amount of SVP-38 progressively increased during a 3-week period after birth in both hydrocephalic and nonhydrocephalic HTX rats, but decayed suddenly at 4 weeks after birth in hydrocephalic HTX rats. When the hydrocephalic HTX rats were treated with V-P shunts, such perturbations in postnatal changes of SVP-38 were prevented completely. In nonhydrocephalic HTX rats, only the embryonic form of drebrins was detected at 1 day after birth, and this disappeared at the end of the 3rd week. The adult form of drebrin could be detected at 1 week after birth, and this completely replaced the embryonic form by 3 weeks of age. However, the postnatal decay of the embryonic form was considerably delayed in hydrocephalic HTX rats. These observations indicate that since synaptogenesis in the brain of hydrocephalic HTX rats has already been disturbed at the prenatal periods, which is the initial process of hydrocephalus, early shunt treatment of hydrocephalus would be beneficial not only for repairing but also for preventing impaired synaptogenesis.

Animals↗