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Biomedical subjects

K Takehara

Publications and source records attributed to K Takehara.

At least 217 records · Page 12Linked to original sources
PubMed1991

Response of scleroderma fibroblasts to various growth factors.

Abnormal growth regulation in lesional skin fibroblasts may be related to scleroderma pathogenesis. We report on the abnormal response of cultured fibroblasts derived from sclerotic lesions to various growth factors. We investigated the responses of skin fibroblasts (10 strains) and normal fibroblasts (9 strains) to the growth factors as PDGF, TGF-beta 1, EGF and basic FGF. Experiments were conducted during the proliferation and confluent stages. PDGF, EGF and basic FGF stimulated fibroblast growth during the proliferation and confluent stages, but the response of scleroderma fibroblasts was significantly lower than that of normal fibroblasts. TGF-beta 1 slightly stimulated confluent fibroblast growth and inhibited proliferating fibroblasts, and the response of scleroderma fibroblasts exceeded that of normal fibroblasts. The decreased response to growth-stimulating factors observed in scleroderma fibroblasts suggests that cultured fibroblasts derived from scleroderma lesions were already senescent because they have been activated by growth-stimulating factors and repeatedly divided in vivo. Thus, abnormal growth regulation of skin fibroblasts may be partially related to the pathogenesis of scleroderma.

Adolescent↗
PubMed1991

Epidemiological study of patients with systemic sclerosis in Tokyo.

We conducted an epidemiological study of systemic sclerosis in the city of Tokyo using the records of patients who had been registered to receive free medical service for intractable diseases. A total of 636 patients were registered as having systemic sclerosis in 1987, and we sent questionnaires to the doctor of each patient. The contents of the questionnaires included the patient's name, sex, age, occupation, major symptoms, therapy and laboratory findings. We received 357 completed replies, and were able to analyse them. Our study estimated that at 1 January 1988 the prevalence rate in Japan was between 2.1 and 5.3 per 100,000. The male/female ratio was 14:1. The ages of the patients when surveyed ranged from 17 to 82 years, with a mean age of 51 years, peaking with the most numerous group being 50-59 years. The characteristic signs of systemic sclerosis were as follows: proximal scleroderma, 75%; sclerodactyly, 91%; pitting scars, 49%; short sublingual frenulum, 49%; pulmonary fibrosis, 45%; diffuse pigmentation, 45%; and phalangeal contracture, 35%. Raynaud's phenomenon was present in 93% of patients, and was the initial symptom in 59% of cases. With respect to specific antinuclear antibodies, anticentromere antibody was present in 19% and antitopoisomerase I antibody was present in 27%.

Adolescent↗
PubMed1991

Sequences and coding strategies of the S RNAs of Toscana and Rift Valley fever viruses compared to those of Punta Toro, Sicilian Sandfly fever, and Uukuniemi viruses.

The sequences and coding strategies of the S RNAs of two viruses, Toscana (TOS) and the M12 derivative of Rift Valley fever ZH-548 (RVF, Phlebovirus genus, Bunyaviridae) have been determined from cDNA clones and compared to the previously published sequences of Punta Toro (PT), Sandfly fever Sicilian (SFS), and Uukuniemi (UUK) viruses. All five viruses exhibit an ambisense coding strategy for their small (S) RNA species, i.e., one gene product (the NSs protein) is encoded in the 5' half of the viral RNA, a second (the N protein) is encoded in the sequence complementary to the 3' half. The terminal nucleotides of the S RNAs of the five viruses are comparable through 13-14 residues. The 3' and 5' ends of these S RNAs have inverted complementary compositions. Three phleboviruses (TOS, SFS, and RVFV) exhibit comparable G-rich, centrally located intergenic sequences, albeit of different lengths. These sequences have a number of similar motifs at, or immediately following, the end of the coding regions, motifs that may be involved in their S mRNA transcription termination processes. The other two viruses (UUK, PT) have AT-rich intergenic sequences that have the potential to form secondary structure. They lack the G-rich sequences or particular sequence motifs recognized in the other three virus RNAs. The deduced sizes of the TOS and RVFV N proteins are 27,704 and 27,430 kDa (respectively). Their NSS proteins are 36,677 and 29,903 kDa (respectively). When aligned, the deduced sequences of the N proteins of the five viruses exhibit homologies ranging from 54 to 30%. The order of homology to RVFV N protein is PT greater than TOS greater than SFS greater than UUK; to TOS N protein it is PT greater than or equal to RVF greater than SFS greater than UUK. The sequences of the NSS proteins are less similar, with values ranging from 30 to less than 17%. The order of homology to RVFV NSS is SFS greater than PT greater than TOS greater than UUK. Due to these more distant relationships, the homologies to TOS NSS protein are less clear.

Amino Acid Sequence↗
PubMed1991

Early detection of scleroderma spectrum disorders in patients with Raynaud's phenomenon.

Fifty patients with the chief complaint of Raynaud's phenomenon (RP) presented at our scleroderma clinic from March to December 1990. Physical examination, routine laboratory tests (blood, urine and chest X-ray), determination of the pattern of RP, antinuclear antibody (ANA) tests and examination for nailfold bleeding were performed. Three patients were diagnosed as having systemic sclerosis sine scleroderma, 15 patients as having RP with positive anticentromere antibody and 6 patients as having an incomplete form of mixed connective tissue disease. Thus, a total of at least 24 patients out of 50 (48%) were shown to have a scleroderma spectrum disorder. A definite RP pattern (triphasic or biphasic and bilateral), positive ANA and positive nailfold bleeding were strongly correlated statistically, suggesting that these are simple useful findings for the early detection of scleroderma spectrum disorders in patients with RP. We expect that there are many undiagnosed patients with an early-stage scleroderma spectrum disorder in the general population.

Antibodies, Antinuclear↗
PubMed1991

Identification and characterization of a plaque forming avian rotavirus isolated from a wild bird in Japan.

From fresh faeces of a wild bird (Melanitta fusca), a virus that showed granular cytopathic effects (CPE) on chicken kidney cell (CKC) cultures was isolated. By indirect immunofluorescence analyses (IFA), this isolate reacted with an antiserum against a bovine rotavirus. The isolate produced clear plaques on CKC by conventional techniques, without trypsin. Three virus plaques were selected by plaque size (small, medium, and large) and cloned by three successive plaque cloning. In the SDS-PAGE analyses, dsRNA bands showed a typical profile of avian rotavirus and quite different from that of avian reovirus. With dsRNA patterns, IFA results, CPE, and a morphological property, the clones were identified as avian rotaviruses of group A rotavirus. The clones killed chicken embryos, when they were inoculated to yolk sac.

Animals↗
PubMed1991

[The titers and complement-activating abilities of anticentromere antibody in systemic sclerosis, other connective tissue diseases, and other related conditions].

The anticentromere antibody is considered to be a useful serologic marker for the CREST syndrome. But this antibody also appears in other related conditions less frequently. We classified 29 patients with anticentromere antibodies into 3 groups: (1) 16 patients with systemic sclerosis or Raynaud's phenomenon alone; (2) 7 patients with other connective tissue diseases; (3) 6 patients with other conditions. Ig class reactivities and complement-fixing abilities of anticentromere antibody were measured by the indirect immunofluorescence test. The whole Ig titers were high (1025 or more) in all patients belonging to group 1. However, the properdin-fixing anticentromere antibody titers of these patients were relatively low (256 or less). In contrast, the patients in group 2 and 3 were shown to have higher C3- and properdin-activating abilities which were determined by the ratios of the titers of C3- and properdin-fixing anticentromere antibody to the IgG titers although the whole Ig titers of these patients were widely distributed. These data suggest that the patients who have low whole Ig titers and/or high properdin-fixing titers do not belong to the scleroderma spectrum and that the patients without clinical features of scleroderma have high C3- and properdin-activating abilities.

Adult↗
PubMed1990

The effects of scleroderma sera on endothelial cell survival in vitro.

The effects of sera and of platelet-poor plasma from patients with scleroderma on endothelial cell survival in vitro were studied. The survival ratio of rat heart endothelial cells was studied both in 10% test serum and in 10% platelet-poor plasma. Sera from patients with scleroderma decreased the survival ratio significantly when compared with sera from normal controls. In contrast, there was no significant difference between platelet-poor plasma from patients with scleroderma and that from normal controls. Our data indicate that platelets in the patients with scleroderma may cause vascular damage by affecting endothelial cell survival.

Adult↗
PubMed1990

Dipyridamole specifically decreases platelet-derived growth factor release from platelets.

The authors have previously reported that dipyridamole decreased platelet-derived growth factor levels in human serum by lowering the release of this factor during blood clotting. In the present study, we have shown that this effect is specific to dipyridamole, and does not occur with other antiplatelet drugs such as aspirin, trapidil or ticlopidine. In addition, dipyridamole has been shown to decrease the PDGF level selectively, but not the levels of other factors from alpha granules in platelets (beta-thromboglobulin and platelet factor 4). These data indicate that dipyridamole may be an effective drug for the prevention of PDGF-related disorders.

Blood Platelets↗
PubMed1990

Characterization of baculovirus-expressed Rift Valley fever virus glycoproteins synthesized in insect cells.

A cDNA corresponding to the complete coding region of the M RNA of the M12 mutant of Rift Valley fever virus (RVFV) strain ZH548 (K. Takehara, M-K. Min, J.K. Battles, K. Sugiyama, V.C. Emery, J.M. Dalrymple, and D.H.L. Bishop, Virology, 169, 452-457, 1989) has been inserted into the baculovirus transfer vector pAcYM1. By comparison with the parent RVFV, the M RNA of the M12 mutant has a new small open reading frame (ORF1) upstream of the one that initiates the precursor of the viral glycoproteins (ORF2, gene order: NS(M)-G2-G1). A derivative of the M12 cDNA was prepared from which most of the upstream sequences (including a polyT tract and ORF1) were removed. Other cDNA constructs were made from this derivative, constructs in which most of the G1 sequences were also removed, or most of the NS(M) coding sequences, or all of the NS(M) and most of G2 coding sequences. Each RVFV M cDNA construct was inserted into a pAcYM1 transfer vector and recombinant baculoviruses were produced (RVM1-5). The derived viruses were employed to study the expression and properties of the RVFV glycoproteins in Spodoptera frugiperda insect cells. For each recombinant virus evidence was obtained which indicated that the RVFV glycoproteins were produced and processed in the insect cells. Although four of the recombinants gave low expression levels of the RVFV glycoproteins, for the vector that made only the G1 product, the expression level was significantly higher. Immunofluorescence analyses established that the RVFV glycoproteins were present both at intracellular locations and on the surface of the recombinant baculovirus infected insect cells.

Animals↗
PubMed1990

Immunocytochemical studies on cholestatic factor in human liver with or without cholestasis.

The localization of the cholestatic factor (CF) was immunocytochemically investigated in liver biopsy specimens obtained from patients with various liver diseases. CF was detected in seven of nine patients with drug-induced liver injury, three of four with acute viral hepatitis, three of five with alcoholic liver injury and in the two patients with autoimmune hepatitis. Fourteen of these 15 CF-positive patients had jaundice in their clinical courses. CF was stained diffusely in the cytoplasm of hepatocytes throughout the lobules in a granular pattern. Electron-microscopically, it was localized on the ribosomes and polysomes as well as on the filamentous structures around the bile canaliculi. However, CF was not detected in liver specimens from normal controls and patients with primary biliary cirrhosis and extrahepatic biliary obstruction. These findings suggest that CF plays an important role in intrahepatic cholestasis in various liver diseases.

Adult↗
PubMed1990

Dipyridamole specifically decreases platelet-derived growth factor release from platelets.

We previously reported that dipyridamole decreased platelet-derived growth factor (PDGF) levels in human serum by lowering the release of PDGF during blood clotting. In this study, we have shown that this effect is specific for dipyridamole, and is not shown in other anti-platelet drugs such as aspirin, trapidil or ticlopidine. In addition, dipyridamole has been shown to decrease the PDGF level selectively, but not the levels of other factors from alpha-granules in platelets (beta-thromboglobulin and platelet factor IV). These data indicate that dipyridamole may be an effective drug for preventing PDGF-related disorders.

Adult↗
PubMed1990

Longitudinal study of patients with anticentromere antibody.

As has previously been reported by many investigators, the anticentromere antibody is considered to be a useful serologic marker for the CREST (calcinosis, Raynaud's phenomenon, esophageal involvement, sclerodactyly and telangiectasia) variant of systemic sclerosis. However, this antibody also appears in other conditions. By screening antinuclear antibody tests using HEp-2 cells as substrate, 39 patients were shown to have the anticentromere antibody. These patients were divided into 4 groups: group 1 = 17 patients with systemic sclerosis; group 2 = 9 patients with Raynaud's phenomenon alone; group 3 = 7 patients with other connective-tissue diseases, and group 4 = 6 patients with conditions other than those present in groups 1-3. Follow-up over years revealed that some patients suffering solely from Raynaud's phenomenon (group 2) developed the symptoms of systemic sclerosis. In contrast, of the patients who did not have Raynaud's phenomenon (group 4), none developed any symptom suggesting systemic sclerosis. We suggest that the simultaneous presence of Raynaud's phenomenon and the anticentromere antibody predicts the occurrence of systemic sclerosis. In contrast, the presence of the anticentromere antibody alone cannot necessarily be used to predict the development of systemic sclerosis.

Adult↗
PubMed1990

Clinical significance of antinuclear antibodies in Japanese patients with systemic sclerosis.

Clinical significance of specific antinuclear antibodies (ANA) in Japanese patients with systemic sclerosis was studied. The patients with systemic sclerosis were classified into four groups according to ANA: (1) anticentromere antibody-positive; (2) anti-Scl-70 antibody-positive; (3) anti-nRNP antibody-positive, and (4) others. The mean score (the number of positive signs in six selected specific signs) of the patients with anti-Scl-70 antibody was significantly higher than those of the other three groups. More frequent contracture of phalanges in the patients with anti-Scl-70 antibody, less diffuse pigmentation in the patients with anti-nRNP antibody, and less pulmonary fibrosis in the patients with anticentromere antibody were revealed. As shown above, the detection of specific ANA in systemic sclerosis is clinically important.

Adult↗
PubMed1990

Systemic lupus erythematosus associated with antiribosomal P protein antibody.

Three patients with systemic lupus erythematosus had positive antiribosomal P protein antibodies. The patients are women who had mild diseases that did not involve prominent internal organs. By using an immunofluorescence method for the detection fo antinuclear antibodies that employs HEp-2 cells, these serum samples produced intense stainings on cytoplasm and nucleoli that were digested with RNase. With the use of an immunoblotting technique, these serum samples recognized three ribosomal P proteins, called PO (38 kd), P1 (19 kd), and P2 (17 kd). We suggest that antiribosomal P protein antibodies can be detected in patients with systemic lupus erythematosus and associated mild clinical features.

Adolescent↗
PubMed1990

[The correlations of respiratory function tests, chest roentgenographic manifestations and respiratory symptoms in the patients with systemic sclerosis, using a scoring-method for symptoms].

Analytical studies were performed on the respiratory symptoms in 31 systemic sclerosis cases. Respiratory symptoms were expressed by scores from 1) coughs, 2) difficulties in walking, 3) difficulties in ascending, 4) dyspnea . In early stage cases with slight clinical symptoms, %VC was always normal, but %DLco was generally reduced. Because of good correlation between respiratory functions and clinical symptom scores, it is available to use the scores as well as %DLLco and %VC to diagnose slight lung involvement in systemic sclerosis. Also the clinical symptom scores are related to the roentgenographic manifestations of lung fibrosis which are characteristic in systemic sclerosis. Therefore we felt that this system of clinical symptom scores was useful to follow-up the patients.

Adolescent↗
PubMed1989

The effects of various growth factors on endothelial cell survival in vitro.

The effects of various growth factors on endothelial cell survival in vitro were studied. Using rat heart endothelial cells, the cell survival curves were obtained; the cells were cultured until confluent, the medium was changed to serum-free medium with or without growth factors, and the cells were counted after 3, 6, 9, and 12 days. Transforming growth factor-beta, which is known as a potent growth inhibitor for vascular endothelial cells, shortened the rat heart endothelial cell's survival period, while epidermal growth factor or transforming growth factor-alpha prolonged survival. Insulin did not affect the rat heart endothelial cell's survival. Our data indicate that growth factors play a role not only in cell proliferation but also in cell survival in vitro. In addition, elevated levels of growth inhibitors such as transforming growth factor-beta may cause tissue damage in vivo by affecting cell survival.

Animals↗