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Biomedical subjects

T Takeya

Publications and source records attributed to T Takeya.

At least 37 records · Page 2Linked to original sources
PubMed1992

Differential screening of ovarian cDNA libraries detected the expression of the porcine collagenase inhibitor gene in functional corpora lutea.

cDNA libraries were constructed from porcine granulosa cells of antral follicles as well as functional corpus luteum, and clones encoding stage-specific genes have been isolated by differential screening. A clone specific to the functional stage of corpus luteum was found to encode the porcine collagenase inhibitor gene and the stage-specific expression in luteinizing tissue was confirmed by Northern blot analysis. The complete open reading frame of the porcine collagenase inhibitor was deduced from the nucleotide sequence, and the localization of the product was examined by immunohistochemical staining as well in pig ovary; the inhibitor was detected in the intercellular space of luteal cells and in the connective tissue around blood vessels in the functional corpus luteum.

Amino Acid Sequence↗
PubMed1992

Tissue-specific expression of two isoforms of chicken fibroblast growth factor receptor, bek and Cek3.

Chicken bek and Cek3 are isoforms of the fibroblast growth factor receptor which consist of primary structures that are identical except for a variation within the last of three immunoglobulin-like repeats in the ligand-binding domain. Northern blot analysis using isoform-specific probes revealed that the bek mRNA is expressed exclusively in lung, whereas the Cek3 mRNA is expressed prominently in brain and weakly in lung. We further localized these transcripts in brain and lung by in situ hybridization histochemistry. In lung, the expression of the bek and Cek3 transcripts was distinguished in the smooth muscle of the parabronchus and in the arterial adventitia. On the other hand, in brain, the Cek3 transcript was detected in three areas: the corpus medullare of the metencephalon (cerebellum), the archiastriatum of the telencephalon, and the ependymal cells of the ventriculare of the mesencephalon. Two putative exons corresponding to isoform-specific sequences, respectively, were found to be closely located on the chicken genome. These results indicate that bek/Cek3 isoforms are derived from the same premessenger and that their expression is regulated in a tissue- or even area-specific manner. Moreover, another potential isoform produced by a new splice site within the Cek3-specific exon has been isolated.

Animals↗
PubMed1992

[A case of childhood epilepsy with occipital paroxysms (CEOP) presenting particular EEG findings].

We reported a case of an eight-year-old boy with CEOP. His parents and sibling were in good health. There was no family history of epileptic and neurological disease. He had his first attack of unconsciousness with fixation of eye movement for a few minutes at the age of 7 years. After six months, he experienced attacks of vomiting followed by loss of consciousness and elementary visual hallucinations consisting of red and blue colors. Sometimes he complained of contraction of visual field for 10 to 20 seconds, as if a curtain had fallen following the visual hallucination of a bright light spot. At the age of eight years, he was admitted to our hospital for evaluation and therapy. Investigations included neurological examination, IQ, CT findings were normal. Visual evoked potential revealed more reduced amplitude in the left side than in the right. The EEG findings during the waking state showed continuous bilateral 1-2 c/s spike and wave complex discharges in occipital and posterior temporal areas. These discharges were immediately suppressed by eyes-opening in an illuminated room, but not in a dark room. However, during the light sleep stage, diffuse irregular spike and wave discharges appeared frequently with left side dominance. From the clinico-electrophysiological findings we diagnosed him as CEOP. In order to investigate the changes of the occipital spike and wave discharges by photic stimulation, we administered intermittent photic stimulation (IPS) for 10 seconds at each frequency between 1-30 flashes/sec (f/s) in a dark room.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1991

Ovarian glycosaminoglycans potentiate angiogenic activity of epidermal growth factor in mice.

Epidermal growth factor (EGF) has been shown to induce capillary proliferation. In the course of our investigation on the interaction of ovarian components with EGF, we observed that partially purified glycosaminoglycans (GAGs) isolated from mouse ovaries enhanced the angiogenic activity of EGF when applied simultaneously to the lateral wall of the sheath of musculus rectus abdominis. Mouse EGF from submandibular glands embedded in Elvax 40 implanting on the musculus rectus abdominis induced neovascularization in a dose-dependent manner. When 0.5 micrograms ovarian GAGs was embedded in the implant with a low amount of EGF that induced only slight neovascularization (0.5 or 1 microgram/implant), the angiogenic activity of the growth factor was markedly enhanced. The active GAG component was isolated by chromatography on Dowex 1-x2. The fraction eluted with 0.5 M NaCl possessed the greatest activity to potentiate the angiogenic activity of EGF. When the reaction mixture of GAGs and EGF was treated with 1% cetylpyridinium chloride, the angiogenic activity was identified with the supernatant. On the other hand, after incubating EGF with 0.5 M NaCl fraction, the angiogenic activity of EGF was identified with the precipitate (GAG fraction) of the cetylpyridinium chloride-treated reaction mixtures. These findings show that ovarian GAGs potentiate the angiogenic activity of EGF by interacting or complexing with EGF.

Abdominal Muscles↗
PubMed1991

Isolation of chicken-bek and a related gene; identification of structural variation in the ligand-binding domains of the FGF-receptor family.

cDNA clones carrying the chicken-bek gene and a related gene were isolated. Deducing the amino acid sequence of chicken-bek allowed us to predict that it encodes for a receptor tyrosine kinase related to the fibroblast growth factor (FGF) receptor, and that the chicken-bek gene and Cek3 are closely related. However, a significant structural difference was identified between chicken-bek and Cek3 within the putative extracellular region, in such a manner that the structure of the immunoglobulin-like domain was conserved. A probe specific to the altered structure detected mRNA in the tissues as did a probe common to bek and Cek3, indicating heterogeneity in the FGF-receptor family in a novel manner. Furthermore, another bek-like gene was isolated and the expressions of its mRNA and protein product were analysed in tissues and cultured cells.

Amino Acid Sequence↗
PubMed1991

[Clinicoencephalographic study of periodic lateralized epileptiform discharges in infants].

The mechanism of periodic lateralized epileptiform discharges (PLEDs) still remains unclear, although it has been the subject of a number of theories. We investigated the relationship between the level consciousness and PLEDs in order to clarify both the clinical significance and the mechanism of PLEDs. We studied two neonates and two infants with acute organic lesions of the brain (cerebral infarction, meningoencephalitis, cerebral hemorrhage, acute infantile hemiplegia), of whom all showing PLEDs in EEG. In each case, we analyzed sequential EEG records and the level of consciousness, and measured the periodicity, voltage and duration of PLEDs by a computer controlled digitizer. In each case, the periodicity and voltage of the discharges were related to the level of consciousness. The appearance rate of PLEDs was relatively high at the level of consciousness from III-100 to III-200. The inverse correlation between the frequency (1/periodicity) and the voltage of PLEDs was significant in 53% of the total records of PLEDs; it was also frequently observed at the level of consciousness between III-100 and III-200. From above findings we concluded that an appropriate degree of damage to produce PLEDs is required in both the cerebral cortex and subcortical white matter corresponding to the level of consciousness from III-100 to III-200.

Acute Disease↗
PubMed1990

[Facioscapulohumeral muscular dystrophy (FSH) and hearing loss].

It has been reported that cochlea is the lesion of hearing loss in FSH. However, the details of this lesion are not yet sufficiently known. We performed detailed audiologic studies to examine hearing loss in FSH. We experienced 2 cases of FSH associated with hearing loss. Case 1 was a girl aged 5 years, and case 2 a boy aged 15 years. Clinical findings, EMG and muscle biopsy gave a diagnosis of FSH in both cases. Hearing loss was evaluated by pure tone audiography, speech audiography, tympanometry, stapedial reflex, auditory brain stem response and electrocochleography. In case 1, pure tone audiograms revealed high tone hearing loss without an A-B gap. On speech audiography, the maximum articulation score was 100% and proved normal. The tympanogram was type A. Stapedial reflex was normal bilaterally. The threshold of the 5th wave increased markedly on auditory brain stem response. On electrocochleography, the H-curve of the input-output function curves of action potential was recorded, but the L-curve was absent. There were no complaints of hearing loss in case 2, but pure tone audiograms revealed high-tone hearing loss without an A-B gap. The tympanogram was type A. Stapedial reflex was normal bilaterally. On auditory brain stem response, threshold was increased and latency was prolonged when intensity was lowered. The electrocochleograms were almost normal. It has been reported that, in electrocochleography, the L-curve represents the function of the outer hair cells and the H-curve that of the inner hair cells. The electrocochleograms in case 1 showed damage to the outer hair cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Reconstitution of nucleosomes in vitro with a plasmid carrying the long terminal repeat of Moloney murine leukemia virus.

The potential of nucleosome assembly along the sequence of a plasmid carrying the long terminal repeat (LTR) and its flanking region of Moloney murine leukemia virus was analyzed by in vitro reconstitution experiments with histones from chicken erythrocytes. The results of electrophoretic mobility-shift and micrococcal nuclease-digestion assays indicated that the plasmid DNA contained four preferred sites for nucleosome formation. However, all of these sites were mapped on the vector moiety but not on the LTR moiety. Computer analysis of the sequences in the four preferred sites, each spanning about 150 bp, indicated that short runs of (dA,dT) containing two kinds of triplets, AAA/TTT and AAT/ATT, occurred frequently. Furthermore, many of these triplets tended to occur in the same side of the DNA helix, suggesting that DNA curvature was involved in the preferred sites for nucleosome assembly. Consistent was the observation that DNA fragments carrying these preferred sites showed anomalous electrophoretic mobilities at a low temperature.

Base Sequence↗
PubMed1989

Phosphorylation of casein components by tyrosine-specific protein kinases.

The phosphorylation of different caseins by a number of tyrosine-specific kinases has been studied. The different kinases showed a range of specificities, suggesting differences in recognition mechanisms. The site of phosphorylation of alpha s2-casein by one phosphorylase has been identified, and compared with analogous sites in other proteins.

Caseins↗
PubMed1989

Childhood transient erythroblastopenia complicated by thrombocytopenia and neutropenia.

We report on 4 children with transient erythroblastopenia complicated by thrombocytopenia and/or neutropenia. Bone marrow examination revealed severe erythroid hypoplasia with normal granulopoiesis and thrombopoiesis. Human parvovirus B19 infection was confirmed serologically in 2 children. An in vitro study using autologous bone marrow cells after recovery demonstrated IgG-mediated inhibition of erythropoiesis in 4 children. Additionally, antibodies directed against platelets and neutrophils were detected. These findings suggest that the IgG-mediated mechanism may be pathogenetic for the transient pancytopenia of these children.

Agranulocytosis↗
PubMed1989

Characterization of partially activated p60c-src in chicken embryo fibroblasts.

Previous studies identified the amino acid changes involved in the activation of p60c-src and revealed that the activation accompanies an alteration of its tyrosine-phosphorylation site. We show here that p60c-src that had been converted to transforming protein by amino acid substitution of the c-src gene either at position 63, 95 and 96, or 338 (J. Kato, T. Takeya, C. Grandori, H. Iba, J. B. Levy, and H. Hanafusa, Mol. Cell. Biol. 6:4155-4160, 1986) and encoded in a Rous sarcoma virus variant was phosphorylated on both Tyr-416 and Tyr-527 in chicken embryo fibroblasts. The results obtained from protease V8 analysis, tryptic peptide mapping, and fractionation with nonionic detergent indicated that the p60 of each variant was present in two forms in the population of the virus-infected cells; one was phosphorylated on Tyr-416, and the other was phosphorylated on Tyr-527. On the other hand, colonies isolated in soft agar contained exclusively p60 of which only Tyr-416 was phosphorylated. These results implied that the limited population of p60 was activated in these Rous sarcoma virus variant-infected chicken embryo fibroblasts and that the activated p60 was concentrated in transformed cells. Furthermore, these two forms of p60 differed in their affinity for the detergent-insoluble cellular matrix in spite of their identical primary amino acid sequences, suggesting that the effect of alteration of the tyrosine phosphorylation site was coupled with the degree of stability of this association.

Animals↗
PubMed1988

Human parvovirus B19-induced transient pancytopenia in a child with hereditary spherocytosis.

We report a child with hereditary spherocytosis who developed human parvovirus B19 (HPV B19)-induced transient pancytopenia. Symptoms of acute-phase illness subsided promptly after infusion of gammaglobulin containing HPV B19 antibody. The HPV B19-containing serum on admission inhibited not only erythroid colony growth but also myeloid and megakaryocyte colony growths. The inhibitory effect was abrogated by convalescent-phase serum or gammaglobulin solution containing HPV B19 antibody. These findings suggest that HPV B19-induced inhibition of haematopoiesis may be pathogenetic for transient bone marrow failure of the patient. The passive immunization may be effective in shortening the duration of acute-phase illness of HPV B19 infection.

Antibodies, Viral↗
PubMed1988

Substitution of Ser-17 of pp60c-src: biological and biochemical characterization in chicken embryo fibroblasts.

pp60c-src is phosphorylated mainly on Ser-17 and Tyr-527 in vivo. In this study, we examined the effect of the phosphorylation of Ser-17 on the properties of pp60c-src by introducing Rous sarcoma virus variants carrying pp60c-src in which Ser-17 had been substituted, into chicken embryo fibroblasts. The Ala-17 substitution in wild-type pp60c-src and pp60c-src carrying Phe-527 caused a two- to threefold elevation in the kinase activity in vitro of these proteins; the former variant resulted in no morphological changes of infected cells, whereas the latter variant transformed chicken embryo fibroblasts. Since the substitution of Tyr-527 per se has been reported to activate pp60c-src, these results suggest that the abolishment of the phosphorylation of Ser-17 does not affect noticeably the properties of pp60c-src in chicken embryo fibroblasts.

Animals↗
PubMed1987

Nuclease S1-sensitive sites on superhelical DNA molecules carrying the LTR region of Moloney murine leukemia virus.

The long terminal repeat (LTR) from proviral DNA of Moloney murine leukemia virus (Mo-MLV) was cloned on a derivative of pBR322, and after introducing superhelical torsions into the resulting recombinant, the sites of conformational transition were investigated by the nuclease S1-digestion method. With an increase in the negative linking differences, fourteen dominant cutting sites were identified, of which two were mapped inside the LTR and one at the 3' end of the LTR. By searching the sequence data, all these sites were localized in the regions having either palindromic sequences or AT-rich sequences. Free energy calculation for the local secondary structure on one strand indicated that nuclease S1 attacked the palindromic sequence regions which could form relatively stable hairpin structures. Under the conditions used, no correlation was found between the S1-sensitive sites and the potential Z-DNA-forming regions, including those within the enhancer sequence.

Base Sequence↗
PubMed1987

Comparison of the structural organizations in the 3'-terminal regions of five avian retrovirus strains: RAV 7, RAV 50, B77, PR-B, and SR-B.

In order to obtain information on the phylogenies of viral strains which belong to RSV (Rous sarcoma virus) and ALV (avian leukosis virus), the nucleotide sequences of noncoding regions adjacent to the U3 region in two ALV strains, Rous-associated virus 7 (RAV 7) and RAV 50, and three RSV strains, Bratislava 77 (B77), Prague:subgroup B (PR-B), and Schmidt-Ruppin:subgroup B (SR-B) were determined by extension from a common primer. The sequences thus deduced were compared with known sequences of other RSV and ALV strains and the structural features of the newly determined viral genomes were discussed.

Avian Leukosis Virus↗