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Biomedical subjects

Y Ota

Publications and source records attributed to Y Ota.

At least 109 records · Page 6Linked to original sources
PubMed1996

Mitochondrial DNA mutations associated with the 11778 mutation in Leber's disease.

To clarify the characteristics of possible synergestic mitochondrial DNA (mtDNA) mutations associated with Leber's hereditary optic neuropathy (LHON), we analyzed the entire nucleotide sequences of mitochondrial genome of two Japanese patients from independent pedigrees harboring the 11778 mtDNA mutation, and compared their sequences with those of 47 disease and 6 normal controls. We have detected several unique mutations in the mtDNA in addition to the 11778 mutation. Two nucleotide substitutions, an A-to-G transition at position 856 in the 12S rRNA gene and an A-to-G transition at 14692 in the T psi C loop of the tRNA(Glu) gene, occurred at highly conserved sites among various species. These mutations in combination with the 11778 mutation might synergetically contribute to the pathogenesis of LHON.

Adolescent↗
PubMed1995

Ligand binding characteristics of the carboxyl-terminal domain of the cytokine receptor homologous region of the granulocyte colony-stimulating factor receptor.

The carboxyl-terminal domain (BC domain, roughly 100 amino acid residues) of the cytokine receptor homologous region in the receptor for murine granulocyte colony-stimulating factor was secreted as a maltose binding protein fusion into the Escherichia coli periplasm. The murine BC domain was prepared from the fusion protein by restriction protease factor Xa digestion and was purified to homogeneity. The purified BC domain specifically and stoichiometrically bound granulocyte colony-stimulating factor. This result indicates that the BC domain is also critical for ligand binding, as shown for the amino-terminal domain of the cytokine receptor homologous region (Hiraoka, O., Anaguchi, H., Yamasaki, K., Fukunaga, R., Nagata, S., and Ota, Y. (1994) J. Biol. Chem. 269, 22412-22419). The tertiary folding and the beta-sheet structure of the BC domain were confirmed by NMR spectroscopy. The disulfide bond pattern suggested from peptide mapping was Cys224-Cys271 and Cys242-Cys285. Disruption of the disulfide bonds suggested that both bonds are critical for maintaining the folding of the BC domain, although a BC domain lacking the second bond still retained ligand binding activity. Mutational analysis of the WSXWS sequence conserved in the cytokine receptor family suggested that this motif is critical for protein folding rather than for ligand binding.

ATP-Binding Cassette Transporters↗
PubMed1995

Requirement for the immunoglobulin-like domain of granulocyte colony-stimulating factor receptor in formation of a 2:1 receptor-ligand complex.

The extracellular portion of the granulocyte colony-stimulating factor (G-CSF) receptor has a mosaic structure of six domains (each approximately 100 amino acid residues) consisting of an immunoglobulin-like (Ig) domain, a cytokine receptor homologous region subdivided into amino-terminal (BN) and carboxyl-terminal (BC) domains, and three fibronectin type III repeats. In the present study, we expressed the Ig-BN and the BN-BC regions and purified them to homogeneity as monomers using G-CSF affinity column chromatography. Using gel filtration high performance liquid chromatography, we investigated the molecular composition of receptor-ligand complexes formed between G-CSF and purified BN-BC or Ig-BN domains. In contrast to the well characterized example of the human growth hormone (GH) receptor, in which the BN-BC.GH complex shows a 2:1 receptor-ligand complex stoichiometry, the BN-BC domain of the G-CSF receptor formed a 1:1 complex. The isolated Ig-BN domain also formed a 1:1 complex with G-CSF. However, in the presence of both Ig-BN and BN-BC domains, we detected a 1:1:1 Ig-BN.G-CSF.BN-BC complex corresponding to the 2:1 receptor: ligand stoichiometry. These results suggest that 1) the Ig domain and both the BN and the BC domains are required for oligomerization of the G-CSF receptor, 2) G-CSF contains two binding sites for its receptor, and 3) there are two ligand binding sites on the G-CSF receptor, one site on the BN-BC domain and one on the Ig-BN domain.

Base Sequence↗
PubMed1995

Studies on neurovirulence in poliovirus-sensitive transgenic mice and cynomolgus monkeys for the different temperature-sensitive viruses derived from the Sabin type 3 virus.

We have studied methods for testing the neurovirulence of live poliovaccine viruses by intraspinal inoculation into mice carrying the human poliovirus receptor gene (Tg mice). A comparison of the neurovirulence of Sabin type 3 vaccine virus and related viruses using the 50% paralysis dose determined after intraspinal inoculation into the Tg mice as an index revealed a close correlation between the results of the paralysis dose in Tg mice, the neurovirulence expressed by the histopathological lesions core in monkeys, and the temperature sensitivity of the viruses. The results of experiments in the Tg mice also showed a good correlation with the number of mutations at position 472 from U to C in the 5' noncoding region in the genomes of the viruses tested. These results strongly suggest that the neurovirulence test for oral poliomyelitis vaccine using the Tg mice is an excellent method and may be used in place of the test using monkeys.

Animals↗
PubMed1995

Neurovirulence test for oral live poliovaccines using poliovirus-sensitive transgenic mice.

The transgenic mice, ICR-PVRTg21, carrying the human poliovirus receptor gene, were intraspinally inoculated with oral poliovirus vaccine viruses and the viruses that had been derived from a vaccine preparation by passagings at 38 degrees. Dose-dependent incidence of paralysis was observed in the transgenic mice inoculated with any of the viruses used. All transgenic mice showing histopathological lesions in the central nervous system appeared to display clinical signs that resembled those observed in human poliomyelitis. These suggest that relative neurovirulence levels of individual virus preparations can be estimated by values of 50% paralysis dose. Indeed, the parameter correlated well with monkey lesion scores of viruses used. Histopathological changes such as degeneration of neurons resemble those displayed by monkeys and were observed in the spinal cord, medulla oblongata, and pons. Thus, the transgenic mice, ICR-PVRTg21, may become a new animal model in place of monkeys for safety testing of oral poliovirus vaccine preparations.

Animals↗
PubMed1995

Electrophoretic analysis of bile proteins from patients with and without gallstones.

Bile proteins from 82 cases with various types of gallstones (pure cholesterol stones, cholesterol stones with a small amount of other substances, mixed stones and pigment stones) and 9 controls without gallstones were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). A unique bile protein with a molecular mass of 32 kDa was identified. The 32 kDa protein could be stained on immunoblotting membranes using immunoperoxidase with concanavalin A. The 32 kDa protein was found in all controls but only in a portion (22.2-36.4%) of the patients with gallstones of various types. Following electrophoretic elution from the SDS-PAGE gels, the 32 kDa protein was analyzed by reversed phase--high-performance liquid chromatography, yielding three peaks for controls and only two peaks for patients with gallstones.

Adult↗
PubMed1995

Can concordant criss-cross heart be ameliorated by hemodynamic changes?

A 2-year-old female child with "ameliorated" concordant criss-cross heart, complicated superior-inferior ventricles, complete transposition of great arteries, hypoplastic right ventricle, ventricular septal defect, and aortic coarctation is described. The patient underwent subclavian flap, pulmonary artery banding, and balloon atrioseptostomy at age 1 month. The ameliorated concordant criss-cross anatomy was obtained after 2 years of follow-up. This dynamic morphologic change allowed us to perform a subsequent anatomic correction.

Aortic Coarctation↗
PubMed1995

Allogeneic peripheral blood stem cell transplantation for treatment of induction failure in a patient with Philadelphia chromosome-positive acute lymphoblastic leukemia.

We report a successful case of allogeneic peripheral blood stem cell transplantation (PBSCT) for the treatment of primary induction failure in acute lymphoblastic leukemia (ALL). The patient was a 46-year-old male with Ph-positive ALL and failed to achieve complete remission (CR). His HLA genotypically identical brother refused to donate bone marrow. Instead, PBSCs were collected by apheresis from the brother after administration of G-CSF at a dose of 10 micrograms/kg. For allogeneic PBSCT, the patient was conditioned with marrow ablative chemotherapy and received the PBSC harvest containing 7.8 x 10(4)/kg of CFU-GM, 1.8 x 10(6)/kg of CD34-positive cells and 2.7 x 10(8)/kg of T lymphocytes. After transplant, the neutrophil count exceeded 0.5 x 10(9)/l on day 16 and the platelet count exceeded 20 x 10(9)/l on day 22. CR was confirmed with tri-lineage engraftment in bone marrow samples on days 28 and 49; disappearance of the Ph-chromosome was documented. Sustained engraftment was also confirmed cytogenetically using a variable number of tandem repeat (VNTR) markers. Acute graft-vs.-host disease did not develop with conventional prophylaxis of methotrexate and cyclosporine. However, on day 85 the patient developed leukemia relapse and died on day 97. This clinical trial suggests that allogeneic PBSCT may be an alternative to allogeneic bone marrow transplantation in some limited situations.

Hematopoietic Stem Cell Transplantation↗
PubMed1995

Cytokeratin fragment 21-1 in gynecologic malignancy: comparison with cancer antigen 125 and squamous cell carcinoma-related antigen.

We measured serum cytokeratin fragment 21-1 (CYFRA 21-1) levels by a solid-phase immunoradiometric assay in 102 healthy Japanese women, and set the reference value at 1.9 ng/ml (mean +2 SD of the serum levels based on a linear distribution). Pretreatment serum CYFRA 21-1 levels were also analyzed in 235 women with benign (n = 94) or malignant (n = 141) gynecologic disease, and were compared with the serum levels of CA 125 and SCC. The respective positivity rates for CYFRA 21-1 and CA 125 were 64.0 and 77.2% in ovarian malignancy, while they were 4.2 and 30.8% in benign ovarian masses. CYFRA 21-1 had an accuracy of 61.3% in diagnosing ovarian malignancy, which was higher than that of CA 125 (53.4%). The positive predictive value of CYFRA 21-1 for ovarian malignancy reached 94.1%, which was significantly (p < 0.005) higher than that of CA 125 (68.8%). These findings indicate the potential usefulness of CYFRA 21-1 as a tumor marker for ovarian malignancy. In addition, the positivity rates fo CYFRA 21-1 in cervical cancer (51.2%) and endometrial cancer (52.2%) were also similar to the respective rates for SCC and CA 125, which suggests that CYFRA 21-1 seems to be a general tumor marker for gynecologic malignancy.

Adolescent↗
PubMed1995

Convenient desktop-scale production of the extracellular domain of the human growth hormone receptor by an insect-baculovirus secretion system using a protein-free culture.

Expression of a gene encoding the extracellular domain of the human growth hormone receptor (hGHR-ED) inserted into the genome of Autographa californica nuclear polyhedrosis virus was done using a desktop-scale spinner culture. Spodoptera frugiperda 9 (Sf9) cells infected with the recombinant virus secreted a protein with hGH-binding activity into the medium. Oxygen supplementation was required for high level secretion of the product. The highest cell production capability was estimated at more than 15 mg hGHR-ED/liter of culture. A protein-free medium supported the production similar to that obtained in traditional serum-containing media. This spinner culture system is simple to operate, and does not require expert knowledge of culture techniques.

Animals↗
PubMed1995

Formation of 1:1 complex of the cytokine receptor homologous region of granulocyte colony-stimulating factor receptor with ligand.

The cytokine receptor homologous (CRH) region of the murine granulocyte colony-stimulating factor (G-CSF) receptor was secreted using a Escherichia coli maltose binding protein (MBP) fusion system. The CRH region was prepared from the periplasmic fraction by G-CSF affinity column chromatography and restriction protease factor Xa digestion, and was purified to homogeneity. The purified CRH region specifically bound G-CSF, with an apparent dissociation constant (kd) of about 1.5 x 10(-9) M. A 1:1 CRH.G-CSF complex was established by gel-filtration high pressure liquid chromatography (HPLC). However, a 2:1 stoichiometric complex was not established, as in the case of the growth hormone (GH) receptor [Recent Prog. Hormone Res., 48, 233-275 (1993)].

ATP-Binding Cassette Transporters↗
PubMed1995

[Anomalous origin of the right pulmonary artery from the ascending aorta: a case report].

We report a successful case of anomalous origin of the right pulmonary artery from the ascending aorta. A 34 days old infant, who had suffered from cardiogenic shock, underwent a direct anastomosis of the right pulmonary artery to the main pulmonary artery behind the ascending aorta under cardiopulmonary bypass. Postoperative catheterization showed no significant stenosis over the anastomosis and normalized pulmonary artery pressure. We conclude that early surgical correction is necessary in the treatment of this life threatening disease.

Anastomosis, Surgical↗