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Biomedical subjects

K Takehara

Publications and source records attributed to K Takehara.

At least 235 records · Page 13Linked to original sources
PubMed1989

EGF and TGF-alpha are potent chemoattractants for endothelial cells and EGF-like peptides are present at sites of tissue regeneration.

We report here that epidermal growth factor (EGF) isolated from male mouse salivary glands is active as a potent chemoattractant for a rat heart vascular endothelial cell line (RHEC). Human EGF and transforming growth factor-alpha (TGF-alpha) produced in Escherichia coli are also active as chemoattractants for these cells. The chemotactic response of the cells is induced by concentrations of murine EGF that ranged from 0.01 to 1.0 nM with similar specific activities for both the human EGF and TGF-alpha. Other growth factors such as fibroblast growth factor (FGF), TGF-beta, platelet-derived growth factor (PDGF), insulin, or IGF were not active as chemoattractants for these cells. The chemotactic response exhibited similar kinetics to those reported for connective tissue cells responding to PDGF (2-6 h) and required both RNA and protein synthesis. However, in contrast to NIH/3T3 cells responding to PDGF, the proliferating cultures of RHEC respond as well as growth-arrested cultures in the chemotaxis assay. In in vivo studies of connective tissue regeneration it appears that EGF-like factors are present in wound fluid collected from rats. Acid extracts of wound fluid contained a RHEC chemotactic activity that was neutralized with anti-EGF antisera. These studies indicate that EGF-like factors may function in vivo to control in part the angiogenic events that occur during tissue repair.

Animals↗
PubMed1989

Mitogenic activities for skin fibroblasts in the sera from untreated scleroderma patients at the early stage.

Mitogenic activities for adult skin fibroblasts in 17 sera from untreated patients with scleroderma at the early stage were studied. Mitogenic activities in 10% test sera were measured by the [3H]-thymidine incorporation assay using confluent fibroblasts; there was no significant difference between scleroderma-affected and normal controls. Growth-stimulatory activities for subconfluent fibroblasts in 10% test sera were measured by increased cell numbers; again, there was no significant difference between scleroderma-affected and normal controls. There have been contradictory reports on growth-stimulatory activities in scleroderma sera; our data do not suggest the presence of a specific mitogen in scleroderma sera.

Adult↗
PubMed1989

Identification of mutations in the M RNA of a candidate vaccine strain of Rift Valley fever virus.

The M RNA species of a candidate vaccine strain of Rift Valley fever virus (RVFV ZH-548M12), derived by consecutive high level mutagenesis using 5-fluorouracil (H. Caplen, C. J. Peters, and D. H. L. Bishop, J. Gen. Virol., 66, 2271-2277, 1985), has been cloned and the cDNA sequenced. The data have been compared to those obtained for the parent virus strain RVFV ZH-548 as well as the previously published data for RVFV ZH-501 (M. S. Collett, A. F. Purchio, K. Keegan, S. Frazier, W. Hays, D. K. Anderson, M. D. Parker, C. Schmaljohn, J. Schmidt, and J. M. Dalrymple, Virology, 144, 228-245, 1985). Some eight nucleotide and three amino acid differences were identified between the M RNAs of ZH-501 and ZH-548. Between the M RNAs of ZH-548 and that of the M12 mutant there were 12 nucleotide and 7 amino acid changes. Unique to the mutant virus is a new AUG codon upstream of that which initiates the open reading frame of the RVFV M gene product (the viral glycoprotein precursor). The significance of this and other differences in the mutant RNA with regard to the derivation and potential attenuation of the candidate vaccine is discussed.

Amino Acid Sequence↗
PubMed1989

Immunogenic and protective properties of rabies virus glycoprotein expressed by baculovirus vectors.

The gene encoding the glycoprotein of rabies virus (G protein, CVS strain) has been cloned and inserted into the baculovirus transfer vector pAcYM1 derived from the nuclear polyhedrosis virus of Autographa californica (AcNPV). The gene was placed under the control of the AcNPV polyhedrin promoter and expressed to high levels by the derived recombinant virus using a Spodoptera frugiperda cell line. It has been established that the antigenic characteristics of the protein were conserved by comparison with those of the native glycoprotein of rabies virions. The immunogenicity of the expressed product was also demonstrated. Intraperitoneal or intramuscular injection of G antigen conferred protection to mice and was associated with the induction of high titers of neutralizing antibodies. The availability of large quantities of antigenically and immunogenically reactive rabies G protein may make feasible crystallographic studies and the safe preparation of a low cost subunit vaccine for the disease.

Animals↗
PubMed1989

Clinical distribution of anticentromere antibody in Japanese patients.

Serum samples from 401 subjects were screened for the presence of anticentromere antibody using HEp-2 cells as the substrate for an indirect immunofluorescence method. Anticentromere antibody was found in 16 cases; 8 out of 62 patients with systemic sclerosis, 3 out of 7 patients with primary Raynaud's disease, 2 out of 41 patients with systemic lupus erythematosus, 1 out of 54 asymptomatic relatives of systemic sclerosis and 2 out of 50 patients with miscellaneous diseases. In systemic sclerosis, the patients with anticentromere antibody were limited in CREST (calcinosis, Raynaud's phenomenon, esophageal involvement, sclerodactylia and telangiectasia) variant. As reported previously by many investigators, anticentromere antibody is considered as a useful immunologic marker for CREST variant of systemic sclerosis, although this antibody is widely distributed in other conditions with less frequency.

Autoantibodies↗
PubMed1989

Atypical scleroderma associated with multiple myeloma.

A case of atypical scleroderma associated with multiple myeloma is reported. The patient was a 50-year-old male; morphea-like plaques with brownish pigmentation were scattered on the whole body and sclerodactylia-like changes, contracture of fingers and polymyositis were observed. Histological findings in the sclerotic lesions were consistent with scleroderma. One year later, M-protein (IgG, kappa-chain) appeared in the serum and 3 years from the onset, the patient was diagnosed as multiple myeloma by bone marrow examination. It is speculated that abnormal immunological reactions related to multiple myeloma caused scleroderma-like lesions.

Collagen↗
PubMed1989

Identification and characterization of an avian reovirus isolated from black-tailed gull (Larus crassirostris).

An isolated virus from the feces of nestlings of Black-tailed gulls living on the Kabu-Island, Hachinohe-city, Aomori-prefecture, was identified as an avian reovirus from its morphological, physicochemical and biological features. Serologically, the isolate has a 62% of relatedness to TS-17 strain, a prototype of avian reovirus in Japan. The isolate showed no significant virulences to one-day-old SPF chickens, and showed low mortalities to chicken embryos, although it formed remarkable lesion onto chorioallantoic membrane.

Animals↗
PubMed1988

Familial clustering of scleroderma spectrum disease.

This is the second case report of familial scleroderma (systemic sclerosis) in South Carolina. The family includes two cases of scleroderma meeting American Rheumatism Association criteria, one of systemic sclerosis sine scleroderma, and two other cases of undifferentiated connective tissue disease with features of scleroderma spectrum disorders; there are also two cases of Raynaud's phenomenon (one associated with rheumatoid arthritis), for a total of seven affected relatives. Evidence of scleroderma spectrum disorders was sought in six siblings of the two co-index cases and in 23 of the 35 offspring. Laboratory studies included antinuclear antibody determinations and typing for the following genetic markers: HLA (A, B, C, DR), complotypes, Gm and Km allotypes, and alpha-1 antitrypsin phenotypes. No common genetic markers restricted to affected members of this family were found, and no environmental exposures were detected that could explain this familial clustering of cases. This report should, however, add to the slowly accumulating information on the genetic characteristics of families at unusually high risk for scleroderma spectrum disorders. Positive antinuclear antibody tests at a titer of 1/40 or higher were present in 57 percent of the first-degree relatives of the affected cases.

Adult↗
PubMed1988

Co-expression of the hepatitis B surface and core antigens using baculovirus multiple expression vectors.

The hepatitis B (HB) virus DNA sequences coding for the pre-core (preC) or C antigens (HBpcAg, HBcAg) have been inserted into the baculovirus plasmid transfer vector, pAcYM1, such that the HB viral sequences are under the control of the polyhedrin promoter of Autographa californica nuclear polyhedrosis virus (AcNPV). Spodoptera frugiperda cells infected with either of the derived recombinant plasmids in the presence of infectious AcNPV DNA yielded recombinant, polyhedrin-negative viruses that expressed high levels of the respective HBpcAg or HBcAg (representing approx. 5 to 10% and approx. 40% of the stained cellular proteins, respectively). The particulate 27 nm HBcAgs have been purified to homogeneity from infected cell extracts by density gradient centrifugation. Dual expression transfer vectors containing the HBcAg gene sequences and the coding sequences of the HB viral S antigen (HBsAg), each gene under the control of its own copy of the polyhedrin promoter, have also been constructed and used to derive recombinant viruses. The recombinant with the HB C and S genes expressed high levels of the HBcAg (approx. 40% of the cellular proteins) and low levels of the HBsAg (approx. 2% of the stained cellular proteins). Dual expression, occluded, recombinant baculoviruses that make HBsAg, as well as the AcNPV polyhedrin protein, have been prepared that are highly infectious for Trichoplusia ni caterpillars, allowing reproducible preparation of the antigen in larvae. Using radioimmunoassays (RIAs) and ELISAs, the recombinant HBcAg (RIA) and HBsAg (ELISA) have been used to identify human antibodies to HB virus with results that compare favourably with the data obtained with non-recombinant antigens.

Amino Acid Sequence↗
PubMed1987

TGF-beta inhibition of endothelial cell proliferation: alteration of EGF binding and EGF-induced growth-regulatory (competence) gene expression.

Transforming growth factor-beta (TGF-beta) inhibits the growth of endothelial cells derived from various sources, including human umbilical vein, bovine aorta, and rat heart. Long-term exposure of rat heart endothelial cells to TGF-beta also induces dramatic changes in morphology that are characteristic of senescent cells. These changes are accompanied by a decrease in the number of high-affinity receptors for epidermal growth factor (EGF), with almost no change in total receptor number. Additionally, the EGF-induced expression of specific competence genes (c-myc, JE, KC) is decreased, whereas the induction of c-fos gene expression by EGF is unaltered by TGF-beta treatment. These data suggest that growth inhibitors such as TGF-beta may act by altering the cell's response to growth-stimulatory factors.

Animals↗
PubMed1987

Ascorbate effects on type I procollagen synthesis by human adult skin fibroblasts: different migration positions of type I procollagen chains on SDS polyacrylamide gel after incubation with ascorbate.

The effects of ascorbate and steroids on type I procollagen synthesis by human skin fibroblasts were studied. Ascorbate treatment (50 micrograms/ml) for 24 hours stimulated a 2-3 fold increase in type I procollagen synthesis and an unexpected shift in the mobility of type I procollagen on SDS polyacrylamide gels. The kinetics of the increase in procollagen synthesis (4 hours) and the shift in electrophoretic mobility (1 hour) were dissimilar, suggesting different controlling mechanisms. This was confirmed by the addition of alpha-alpha'-dipyridyl to ascorbate-treated cultures which eliminated the ascorbate-induced shift in electrophoretic mobility without altering the amount of procollagen synthesis. In contrast, hydrocortisone (1.5 microM) reduced the ascorbate-induced stimulation of type I procollagen synthesis by 80% but did not affect the ascorbate-induced shift in electrophoretic mobility. These studies indicate that the ascorbate-induced increase in type I procollagen synthesis is due to increased levels of type I procollagen mRNA and is independent of the level of hydroxylation of the procollagen.

2,2'-Dipyridyl↗
PubMed1986

Tubulointerstitial immune complex nephritis in a patient with cutaneous vasculitis.

We report a patient who suffered from cutaneous vasculitis with renal involvement comprising tubulointerstitial (TI) nephritis and relatively mild glomerulitis. Renal biopsy revealed immune deposits both in mesangium and along tubular basement membrane (TBM), suggesting that immune complexes played a significant role in the development of renal damage. Although it is well known that vasculitic syndromes commonly affect glomeruli, this report is the first to demonstrate tubulointerstitial immune complex nephritis in a patient with cutaneous vasculitis.

Adult↗