Biomedical subjects

S Kishimoto

Publications and source records attributed to S Kishimoto.

At least 199 records · Page 11Linked to original sources

PubMed1990

Effect of retinoic acid on proliferation of estrogen-responsive transformed murine Leydig cells in serum-free culture.

B-1 F cells, one of the sublines established from mouse Leydig cell tumor, have been found to be maintained as an estrogen-responsive cell line under the serum-free culture conditions. Reported results that retinoids have action mechanisms similar to those of estrogen prompted us to examine the effect of retinoids on the proliferation of B-1 F cells. Stimulation of B-1 F cell growth by retinoic acid in a dose-dependent manner was observed, whereas retinoic acid did not promote but inhibited the proliferation of MCF-7 cells (estrogen- and retinoic acid receptor-positive human breast cancer cells). To elucidate the mechanism of retinoic acid-dependent cell growth, simultaneous treatment with retinoic acid and estradiol was carried out. The result did not show the additive effect on B-1 F cell growth. Hydroxytamoxifen, a potent antiestrogen, inhibited not only estradiol-dependent but also retinoic acid-dependent cell growth. However, retinoic acid failed to be associated with estrogen receptor, suggesting that retinoic acid induced enhancement of B-1 cell growth through its interaction with retinoic acid receptor. Northern blot analyses of polyadenylated RNA with complementary DNA probes for human retinoic acid receptor alpha, beta, and gamma revealed the presence of transcripts encoded by retinoic acid receptor alpha gene in B-1 F cells. These results would suggest that enhancement of the B-1 F cell growth is mediated through interaction of retinoic acid with retinoic acid receptor alpha. This stimulatory activity is inhibited by estrogen receptor complexed with hydroxytamoxifen.

Animals↗

PubMed1990

Effects of estrogen on cell proliferation and leukotriene formation in transformed mouse Leydig cells cultured under serum-free conditions.

B-1 F cells from mouse Leydig cell tumor (T 124958-R) were maintained in serum-free culture. Estrogen enhanced the growth of the cells, and this growth was suppressed by antiestrogens such as 4-hydroxytamoxifen or TAT, a newly developed antiestrogen. Since the growth of B-1 F cells was recently found to be inhibited by the metabolites of arachidonic acid, we examined the relationship between this metabolism and the enhancement of cell growth by estrogen. Among the modulators affecting the metabolism of arachidonic acid, 2-(12-hydroxydodeca-5,10-diynyl)-3,5,6-trimethyl-1,4-benzoqu inone, an inhibitor of 5-lipoxygenase, reproducibly stimulated the growth of the cells, whereas the cyclooxygenase inhibitor indomethacin had only the marginal growth-stimulatory effects. Phorbol ester had no growth-modulating effect. 17 beta-Estradiol and 2-(12-hydroxydodeca-5,10-diynyl)-3,5,6-trimethyl-1,4-benzoqu inone had some additive effects especially in terms of restoration of antiestrogen-induced inhibition. Moreover, the inhibition of DNA synthesis elicited by the addition of arachidonic acid in concentrations of 0.05 to 0.5 micrograms/ml was partly blocked by estrogen. Analyses of extracts of media and cells by high-pressure liquid chromatography and radioimmunoassay showed that 17 beta-estradiol inhibited the synthesis of leukotrienes B4, C4, D4, and E4 and this inhibition could be restored by antiestrogen. These results suggest that the enhancement of B-1 F cell growth by estrogen is at least partly mediated through its ability to inhibit leukotriene synthesis.

Animals↗

PubMed1990

Immature B cells can pass through a VHDJH/germ line state in the Ig H chain gene rearrangements.

SPL2-1-2, an Ig- murine immature B cell line, was established by the infection of immature B cells with tsOS-59, a temperature-sensitive mutant of Abelson murine leukemia virus. Southern blot and DNA cloning and sequencing analysis showed that SPL2-1-2 had a nonproductive VHQ52.DSP2.JH3 and a germ line (G) allele (VHDJH-/G), and that D to JH joinings followed by VH to DJH joinings progressed on the G allele during culture. These results indicated the existence of novel pathway of IgH gene rearrangements: G/G----DJH/G----VHDJH/G----VHDJH/DJH----VHDJH /VHDJH. This also implied that whether DJH/G state progressed to DJH/DJH or VHDJH/G state was stochastically determined, but not strictly controlled in an ordered fashion, although DJH/G state progressed more preferentially to DJH/DJH state than to VHDJH/G state.

Alleles↗

PubMed1990

Estimation of D segment usage in initial D to JH joinings in a murine immature B cell line. Preferential usage of DFL16.1, the most 5' D segment and DQ52, the most JH-proximal D segment.

We established SPL2-1-2, a murine immature B cell line transformed by tsOS-59, a temperature-sensitive mutant of Abelson murine leukemia virus. SPL2-1-2 has a VHDJH-/G (germ-line) configuration, and can continuously generate D to JH joinings from the germ-line allele during culture. The D to JH joinings are strongly promoted by the shift of the culture temperature from permissive (35 degrees C) to non-permissive temperature (39 degrees C). Using this H chain gene rearrangement system, we succeeded in the estimation of the frequencies of D segment usage in initial D to JH joinings by deletion-mapping analysis. The results demonstrated the preferential utilization of DFL16.1, the most 5' D segment and DQ52, the most JH-proximal D segment in initial D to JH joinings.

Alleles↗

PubMed1990

Affinity chromatography of human plasma gelsolin with polyphosphate compounds on immobilized Cibacron Blue F3GA.

Human plasma gelsolin was specifically eluted from a Cibacron Blue F3GA column with 1 mM adenosine, guanosine, cytidine and uridine di- and triphosphates, except for cytidine 5'-diphosphate. Inorganic polyphosphates also eluted gelsolin, but neither nicotinamide adenine dinucleotide nor nicotinamide adenine dinucleotide phosphate did so. The results suggest that a terminal pyrophosphate structure might be essential for the specific elution. After elution with 1 mM adenosine 5'-triphosphate, additional gelsolin was eluted by washing the column with a high salt concentration. This indicates that human plasma gelsolin may bind to Cibacron Blue F3GA in at least two different ways.

Adenine Nucleotides↗

PubMed1990

Antidromically evoked facial nerve responses in guinea pigs: a basis for clinical applications in patients with facial palsy.

We investigated the differences in wave form in antidromically evoked facial nerve responses in guinea pigs with and without facial nerve dysfunction. The antidromic facial nerve responses were evoked with alternative stimulation of positive and negative square-wave pulses of 0.1 ms duration and recorded at the bony fallopian canal near the geniculate ganglion. One hundred responses were summed by a signal processor. The application of alternative stimulations made it possible to eliminate stimulus artifacts and to analyze precisely the waves with latencies shorter than 0.5 ms in the test animals. Normal antidromic facial nerve responses showed a triphasic wave form with two positive and one negative peaks. A blockade of the nerve between the recording and stimulating sites resulted in transformation of the wave into a monophasic one. A proximal blockade to the recording site changed the wave form to a biphasic shape. These findings suggest that the site of an intratemporal facial nerve lesion can be predicted from the wave forms evoked by antidromic facial nerve responses.

Animals↗

PubMed1990

Growth advantage by overexpression of normal Harvey ras proto-oncogene in cultured rat epidermal keratinocytes.

The ras proto-oncogene is frequently amplified and overexpressed in the hyperproliferative conditions of epidermal keratinocytes. To investigate the effects of its overexpression on the growth of keratinocytes in a model system, we constructed expression vectors for normal human Ha-ras and introduced them into FRSK cells, a fetal rat epidermal keratinocyte cell line. Several clones containing the transfected Ha-ras were isolated, and two of them overexpressed this gene. In these clones DNA synthesis and cell growth were greater than in other clones expressing this gene at low levels. Thus we suggest that overexpression of normal ras gene may provide growth advantage to epidermal keratinocytes.

Animals↗

PubMed1990

Spontaneous activation of heat shock protein gene transcription in peripheral blood mononuclear cells of individuals with active systemic lupus erythematosus.

In the present study, we show the spontaneous elevation of the transcription of heat shock protein (hsp 70) gene in peripheral blood mononuclear cells (PBMC) of individuals with active systemic lupus erythematosus (SLE) by nuclear run-on transcription assay. For quantification analysis of hsp 70 gene transcription, we first found more than ten times of the enhanced transcription of hsp 70 gene in PBMC of individuals with active SLE, as compared to normal healthy subjects or patients with bronchial asthma as controls. Our observation suggests that heat shock proteins may be produced during an active immune response in individuals with active systemic lupus erythematosus and is involved in lupus-related change of possible essential function in PBMC.

Female↗

PubMed1990

Identification of unoccupied but transformed nuclear estrogen receptor in cultured mouse Leydig cell.

The molecular forms of estrogen receptor (ER) in estrogen-responsive mouse Leydig cell line (B-1) have been examined in relation to their biological activity. ER was predominantly recovered in the nuclear fraction upon homogenization even after cells were precultured in the absence of E2 and Phenol Red. This unoccupied nuclear ER (ERn) whose hormone binding ability was extremely thermostable could be extracted with 0.4 M KCl. This stability enabled us to determine hydrodynamic parameters in the ligand-free condition. The Stokes radius and sedimentation constant of this ERn in high salt condition were 5.5 nm and 6.0S, respectively, resulting in its molecular weight of 140,000. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of ER labeled with [3H]tamoxifen aziridine gave a single band of 65,000 Da, indicating that this ERn had a oligomer structure similar to that of transformed nuclear ER complexed with estrogen in the putative target cells. Therefore, we further examined the possibility that this ERn in B-1 cells can activate estrogen-responsive genes without any aid from estrogen. Estrogen responsive element-thymidine kinase promoter-chloramphenicol acetyltransferase fusion gene (ERE-tk-CAT) was transfected into B-1 cells. CAT activity was enhanced only in cells stimulated with estrogen. It may be concluded from these results that transformed ERn can be formed in the absence of estrogen but that binding to estrogen may be required in order to exert its biological activity.

Animals↗

PubMed1990

Taurine modulates ion influx through cardiac Ca2+ channels.

The effects of taurine on the inward Ca2+ current (ICa) were investigated by means of the whole-cell voltage-clamp technique in isolated single guinea pig ventricular myocytes. ICa were elicited by 200-ms test pulses from a conditioning holding potential of -45 mV to various test potentials at a rate of 0.5 Hz. Taurine (10-20 mM) had different effects on ICa, depending on the extracellular Ca2+ concentration [( Ca]o). A small stimulatory effect of taurine was found in low [Ca]o (0.8 mM), and a small inhibitory effect was found in high [Ca]o (3.6 mM). Taurine had no significant effect on ICa in normal [Ca]o (1.8 mM). Such dual effects on ICa may explain the various effects reported for taurine especially its dual inotropic actions on cardiac muscle depending upon [Ca]o. Thus, taurine acts in a manner to keep ICa relatively constant. Taurine increased the resting potential irrespective of [Ca]o, suggesting that, in addition, taurine increased K+ conductance and/or ion exchange systems such as the Na/Ca and Na/K exchange.

Action Potentials↗

PubMed1990

Differential detection of human papillomavirus DNA type 6 and 11 amplified by polymerase chain reaction.

We have developed a method for differential detection of human papillomavirus type 6 and 11 with selective amplification of a segment of the viral DNAs by the polymerase chain reaction. The target sequence for amplification was a 134-bp (bp 206-339) in the E6 open reading frame of HPV 6 and 11 DNAs. DNA extracted from a paraffin-section or a minute fresh biopsy specimen of condyloma acuminatum was amplified and hybridized with an oligonucleotide probe specific for HPV 6 or 11 DNA. The method was applied to analyse 5 cases of genital condyloma acuminatum, and as a result, HPV 6 and 11 DNAs were detected in two and one case, respectively. This method is useful for differential diagnosis of HPV 6 and 11 infection.

Base Sequence↗

PubMed1990

Basophil histamine release by platelet-activating factor in aspirin-sensitive subjects with asthma.

Histamine release induced by platelet-activating factor (PAF) from leukocytes of aspirin-sensitive subjects with asthma was higher than that from normal control subjects, despite the similarity of anti-IgE-induced histamine release. Moreover, basophils of some aspirin-sensitive subjects with asthma released histamine by PAF stimulation in the absence of cytochalasin B that affects histamine release and is required in PAF-induced histamine release from leukocytes of atopic subjects with asthma and normal control subjects. In addition to temperature dependency and inhibition by ethylenediaminetetraacetic acid reported previously, PAF-induced histamine release was enhanced by cytochalasin B and indomethacin and inhibited by dexamethasone. These features are common with IgE-mediated histamine release and suggest the existence of the common pathway to PAF-induced histamine release and IgE-mediated histamine release. The results in the present study indicate the pathophysiologic significance of PAF-induced histamine release and that activation of basophils by PAF may be relevant to the pathogenesis in some aspirin-sensitive subjects with asthma.

Adult↗

PubMed1990

Elevated expression of heat-shock protein gene in the fibroblasts of patients with scleroderma.

1. Scleroderma is a systemic autoimmune disorder characterized by fibrosis affecting the skin, lung, kidney and other organs. The 70 kDa heat-shock protein has been implicated as essential for cell function during cell growth and differentiation. To study the molecular basis of intracellular events in sclerotic fibroblasts, we compared the expression of the hsp 70 gene in sclerotic and normal control fibroblasts by a run on nuclear transcription assay and a Northern blot assay. 2. In the run on nuclear transcription assay, sclerotic fibroblasts expressed an approximately eightfold higher level of hsp 70 transcription than normal fibroblasts in the quiescent condition after serum starvation. After stimulation with serum, the transcription level of the hsp 70 gene was almost similar in sclerotic and normal control fibroblasts. 3. In the Northern blot assay, the hsp 70 gene transcript, which was present in increased amounts in sclerotic fibroblasts, exhibited normal size.

Blotting, Northern↗

PubMed1990

Human plasma gelsolin binds adenosine triphosphate.

Binding studies of human plasma gelsolin with ATP were done by equilibrium dialysis. Analysis of the binding data showed that plasma gelsolin had one class of ATP binding site with Kd = 2.8 x 10(-7) M, which saturated at an ATP/gelsolin ratio of 0.6. The bioluminescent assay for ATP with luciferin and firefly luciferase confirmed that the protein contained a nucleotide as ATP.

Adenosine Triphosphate↗

PubMed1990

Further study of mucosal repair by sofalcone in experimental gastritis.

The effect of sofalcone on the glandular structure and cell proliferation in the gastric mucosa of rats with gastritis induced by the administration of sodium taurocholate (TCA) for 6 months was examined by histoquantitative analysis and [3H]thymidine autoradiography. Morphometric observation revealed that, with TCA treatment, mucosal thickness, parietal cell mass, and the ratios of the length of the glandular portion/total length of the gastric gland were decreased in both the fundic and pyloric glands. Inflammatory cell infiltration and collagenous fiber proliferation were present in the gastric mucosa following TCA and indicated the presence of atrophic gastritis. These atrophic changes and inflammatory cell infiltration were reversed by a 3 week administration of sofalcone. Cellular proliferative activity assessed by the labeling indices of the gastric mucosa increased in TCA-induced gastritis in rats. The administration of sofalcone to rats with TCA-induced gastritis significantly increased labeling indices, particularly in the pyloric glands. From these results, it appears that sofalcone stimulates the compensatory increase in proliferative activity of generative cells, which then may become available to heal the gastritis.

Animals↗

PubMed1990

The in vivo anti-tumor effect of human recombinant interleukin-6.

Administration of recombinant interleukin-6 (IL-6) was found to induce in vivo generation of cytotoxic T lymphocytes (CTL) against syngeneic transplantable erythroleukemia (FBL-3) in lymph node cells and peritoneal exudate cells (PEC) in C57BL/6 mice. Furthermore, 15 out of 16 C57BL/6 mice injected with 5 x 10(6) viable FBL-3 cells survived on day 100 when they were treated with 5 x 10(4) U of recombinant IL-6 three times a day on days 1, 2, 3, 5, 7 and 9 after the inoculation of tumor cells (the cure rate was 94%). Cured mice could reject the tumor cells rapidly after the re-inoculation of a large number of live FBL-3 cells. In contrast, all normal mice died of tumor development by day 10. In these cured mice, FBL-3-specific CD4-8+ CTL cells were found to be generated in PEC, spleen and lymph node cells by either in vivo or in vitro re-stimulation with FBL-3 cells, but lymphokine-activated killer cells never developed. The results suggested that the anti-tumor effect of IL-6 was mediated by in vivo induction of tumor-specific CTL.

Animals↗

PubMed1990

Enhanced expression of the tumour necrosis factor/cachectin gene in peripheral blood mononuclear cells from patients with systemic vasculitis.

The expression of tumour necrosis factor-alpha (TNF-alpha) gene in peripheral blood mononuclear cells from patients with systemic vasculitis, periarteritis nodosa and Wegener's granulomatosis, has been studied by RNA dot blot and Northern blot assays. We further examined the transcriptional level of TNF-alpha gene in peripheral blood mononuclear cells from these patients by performing nuclear run on transcription assay. We demonstrate enhanced TNF-alpha gene expression in mononuclear cells from these patients compared with healthy subjects and patients with bronchial asthma. These findings suggest that the enhanced transcription of TNF-alpha gene in peripheral blood mononuclear cells from patients with systemic vasculitis may be involved in the pathophysiology/pathogenesis of these diseases by cytokine dysregulation.

Adult↗

PubMed1990

Elevated transcription of heat shock protein gene in scleroderma fibroblasts.

Scleroderma is a systemic disorder characterized by fibrosis, which affects skin, lung, kidney and other organs. Heat shock protein (hsp) (70 kD) has been implicated as an essential element of cell function in cell growth and differentiation. To study the molecular basis of intracellular events in scleroderma fibroblasts, we compared the expression of hsp 70 gene in scleroderma and normal control fibroblasts by nuclear run on transcription assay and Northern blot assay. We show that scleroderma fibroblasts express more than eight times higher level of hsp 70 transcription in normal control fibroblasts at quiescent conditions in the absence of serum. After stimulation with serum, the transcription level of the hsp 70 gene is similar in scleroderma and normal control fibroblasts. Therefore, our results indicate an alteration/activation of intracellular events in scleroderma fibroblasts.

Adult↗