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S Odashima

Publications and source records attributed to S Odashima.

At least 37 records · Page 2Linked to original sources
PubMed1995

Electroporation-mediated transfection of mammalian cells with crude plasmid DNA preparations.

We designed a simple and reproducible electroporation-mediated transfection procedure with which to screen mammalian expression vector-constructed cDNA libraries. Using a specific chamber composed of five parallel electrodes, the recipient cells can be electroporated separately with 40 plasmid DNA preparations in a single experiment. Over 300 crude plasmids prepared from E. coli (DH-5) carrying a pcD2neo-vector-derived cDNA library were tested. The efficiency of stable transfection by electroporation with crude plasmid DNA preparations was 10-times higher than with the CsCl-purified plasmid DNA. When the crude plasmids were digested with RNase, the efficiency of stable transfection markedly decreased, indicating that the contaminating bacterial RNA in the crude plasmid preparations has a strong carrier effect during the electroporation. Even when salmon sperm DNA or genomic DNA from the recipient cells was used as the carrier of the purified plasmid, the efficiency was not higher than that using the crude preparations. This procedure is useful not only for screening a number of cDNAs but also for routinely introducing biologically active foreign genes into cultured mammalian cells.

3T3 Cells↗
PubMed1995

The important role of PKC in controlling polyploidy formation in cultured fibrosarcoma cell line.

Induction of polyploidization by colcemid in cultured fibrosarcoma cells (Meth-A cells) was examined. Activators of protein kinase C (PKC), phorbol 12-myristate 13-acetate (PMA) and ATP, inhibited colcemid-induced polyploidization, but not colcemid-induced cell proliferation cessation. These findings suggest that a down-regulation of PKC activity results in checkpoint "dysfunction" which induces polyploidization and that inhibition of polyploidization induction by PMA and ATP is not a result of the inhibition of colcemid-induced depolymerization of tubulin.

Adenosine Triphosphate↗
PubMed1995

[A case of primary pulmonary hemangiopericytoma recurred locally 10 years after the first surgery].

Hemangiopericytoma is a rare tumor of vascular origin. This tumor has a malignant potential and often recurs or metastasize. A case of primary pulmonary hemangiopericytoma which recurred locally 10 years after the first surgery is presented. The histological appearance of the tumor had some findings of malignant potential in both of the primary and recurrent lesions. We discussed on malignant potential of this tumor in the number of mitotic figures, cellular atipia, and DNA ploidy pattern.

Female↗
PubMed1994

Potentiation of K252a, a protein kinase inhibitor-induced polyploidization by cAMP in cultured fibrosarcoma cell line.

We found that K252a, a potent inhibitor of protein kinases (PK), induced DNA re-replication of Meth-A cells, i.e., DNA synthesis at a higher DNA ploidy without undergoing cytokinesis (polyploidization). The K252a-induced polyploidization was inhibited by phorbol 12-myristate 13-acetate (PMA), a protein kinase C (PKC) activator, suggesting that the polyploidization is caused through inhibition of PKC. By contrast, the polyploidization was potentiated by adenosine 3':5'-cyclic monophosphate (cAMP), a cAMP-dependent protein kinase (PKA) activator. These findings suggest that the cAMP-dependent signaling pathway and diacylglycerol (DAG)-dependent signaling pathway play an important role in regulating the induction of polyploidization in Meth-A cells, through a possible "cross-talk" between the two pathways.

Adenosine Triphosphate↗
PubMed1994

Apoptosis by demecolcine in V79 cells.

Demecolcine (Colcemid), an inhibitor of spindle fiber formation in M phase, induced apoptosis in V79 cells. At a concentration of 0.01 microgram/ml demecolcine, V79 cells proliferated exponentially as well as controls, although temporal M phase accumulation occurred 6 h after the addition of demecolcine. At 0.1 microgram/ml, the cells became hyperploid after remaining in the M phase for some time. Apoptosis occurred in V79 cells exposed to demecolcine at a concentration of 0.03 microgram/ml. Apoptosis was defined as the appearance of a sub-G1 peak in DNA histograms and a ladder pattern of fragmented DNA in gelelectrophoresis.

Animals↗
PubMed1993

Hyperploidization of V79 cells by K-252a in comparison with demecolcine.

The cellular responses of the V79 cell cycle to K-252a, a protein kinase inhibitor, were examined by flow cytometry (FCM) and by time-lapse videomicrography. At a concentration of 0.5 microM of K-252a for 72 h, V79 cells became hyperploid, having above 32c DNA content. The cycle times in the hyperploidizing process were 11.2 (4c-8c), 16.3 (8c-16c) and 19.3 (16c-32c) hours, values which were less than twice that of the control (10.5 h). After the washout of K-252a, the DNA content was widely distributed in the V79 cell population and hyperploid V79 cells reduced DNA content through a variety of cell division modes. These cellular responses to hyperploidization of V79 cells by K-252a were in reasonable agreement with those by demecolcine.

Animals↗
PubMed1993

Involvement of peanut agglutinin-binding sugar chains in experimental metastasis of B16 melanoma cells.

Involvement of PNA (peanut agglutinin)-binding sugar chains in experimental metastasis of B16M4 cells and their metastatic variants (B16F1, B16F10, and B16BL6) was investigated by using ginsenoside Rh2 (Rh2), which increased PNA binding to the cell surface without increasing concanavalin A or wheat germ agglutinin binding. The PNA binding to cell surface increased in parallel with the experimental metastatic ability in Rh2-treated B16M4 cells, and this increase in metastatic ability was suppressed when the cells were treated with PNA before i.v. injection of cells. Concanavalin A and wheat germ agglutinin did not have such inhibitory effects. Increased PNA binding was observed on glycoproteins of M(r) 75,000-85,000, and was suggested to be due to reduced sialylation of PNA-binding sugar chains on these glycoproteins. In Rh2-treated B16F10 and B16BL6 cells, the increase in experimental metastatic ability was also associated with increased PNA binding to cell surface and M(r) 75,000-85,000 glycoproteins. Although the mechanisms of these effects of Rh2 are unknown, these results suggested that the reduced sialylation of PNA-binding sugar chains on M(r) 75,000-85,000 is related to the increased experimental metastatic ability of Rh2-treated B16 melanoma cells.

Animals↗
PubMed1992

Isolation and characterization of a low metastatic variant from EL-4 mouse T-lymphoma.

A variant cell line (EL-4ad) which adhered to a tissue culture dish was isolated from highly metastatic EL-4 murine T-lymphoma. The experimental and spontaneous metastatic ability of EL-4ad was lower than that of the EL-4 parent cell line. The cell surface phenotypes of both cell lines were CD2+3+4-8-45+TCR alpha beta+TCR gamma delta-, but the level of CD2 expression of EL-4ad was much lower than that of EL-4. Furthermore, EL-4ad had higher binding ability to fibronectin and expressed more PNA receptors on the cell surface than EL-4. These differences indicated that either the maturation stage of the less metastatic variant was lower than that of the parent cell line or the activation state of the two cell lines differed. EL-4ad showed higher in vitro invasiveness and adhesiveness to liver cells, and these characters were not consistent with the reduced metastatic ability of this variant. Neuraminidase-releasable cell surface sialic acid levels did not differ significantly between the cell lines. Neither cell line was adhesive to laminin, type IV collagen or reconstituted basement membrane. These metastasis-related properties could not explain the decreased metastatic ability of EL-4ad. On the other hand, EL-4ad was more sensitive to NK activity than EL-4 in vivo, and this was thought to be a major cause of its decreased metastatic ability. The molecules or mechanisms involved in the differentiation or activation of T-cells may be responsible for the sensitivity of tumor cells to NK activity.

Animals↗
PubMed1991

Mechanism of action of ginsenoside Rh2: uptake and metabolism of ginsenoside Rh2 by cultured B16 melanoma cells.

The uptake and metabolism of ginsenoside Rh2 (Rh2) by B16 melanoma cells were studied. In a medium containing 2% fetal calf serum, the uptake of Rh2 reached a maximum of 3 nmol/10(6) cells at 3-6 h after Rh2 (12.5 microM) was added, but gradually decreased to 0.8 nmol/10(6) cells. In these cells, protopanaxadiol (PPD), which is an aglycon of Rh2, increased inversely with the decrease in Rh2 as a result of deglycosylation by the cells. When PPD (8 microM) was added to the medium, the uptake reached a plateau of 2.4 nmol/10(6) cells, within 0.5 h. The association constant of Rh2 (1.74 +/- 1.08 x 10(6) M-1) for bovine serum albumin (BSA) was significantly higher than that of PPD (9.90 +/- 1.10 x 10(4) M-1). In a serum-free medium, both Rh2 and PPD were incorporated within 1.5 h. The uptake rate constant of Rh2 (1.20 +/- 0.20 h-1) was not significantly different from that of PPD (1.02 +/- 0.15 h-1), but the release rate constant of PPD (2.12 +/- 0.38 h-1) was significantly lower than that of Rh2 (3.03 +/- 0.57 h-1). These differences in affinity for BSA and the release rate constants were thought to be the cause of the difference in uptake kinetics between these drugs. The effects of Rh2 and PPD on the cells were identical, and there was no difference in the lag periods before the appearance of their effects, despite their differing rates of uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Quantitative cytochemical studies of cytochrome oxidase activity in rat dorsal root ganglion cells.

The cytochrome oxidase activity of rat dorsal root ganglion cells was cytochemically and quantitatively measured. The 100 microns thick tissue slices fixed for 10 min were incubated in a DAB medium for 0, 30, 60, and 90 min at 37 degrees C, and electron-dense deposit areas within the mitochondrial intermembrane-intracristal spaces were measured with a computer-controlled image analyzer. The activity was expressed as deposit accumulation rate filling the mitochondrial space, (1 unit corresponds to the deposit filling 100% of the mitochondrial space per hour). Three different activities of the enzyme in either large pale cells or small dark cells of sensory neurons could be distinguished, based on the quantitative analysis, as large cells with intense (0.83 units), intermediate (0.38), and weak activity (0.22), and small cells with the same degrees of activity (1.04, 0.35, and 0.11, respectively). The results indicate that accumulation rate measurements of reaction product may be useful to quantitatively present the cytochrome oxidase reactivity of mitochondria, and that the degree of enzyme activity may contribute to the identification of functional differences in sensory neurons.

Animals↗
PubMed1989

Synergistic effects of hydroxyurea and thymidine on the growth inhibition of V79 cells.

The effects of hydroxyurea (HU) and thymidine (TdR) on cell cycle progression in V79 Chinese hamster lung cells were examined by flow cytometry. Suppression of the cell cycle progress rate by HU was further enhanced by the combination of a low concentration of TdR and HU as compared to that induced by TdR alone; i.e., these drugs were shown to have a synergistic effect. It was concluded that the presence of TdR was effective in assisting HU-induced suppression of DNA synthesis.

Animals↗
PubMed1989

Effects of hydroxyurea on the phagocytosis of microspheres in V79 cells.

Phagocytosis of fluorescent microspheres in V79 cells arrested in the S phase by hydroxyurea (HU) was investigated by flow cytometry. The phagocytic activity increased with the exposure time of HU. No dependency on the HU concentration was observed in the concentration used. Cell size (projection area) and membrane fluidity, two factors effected by HU treatment, were examined in relation to phagocytic activity, and were found to be significantly increased. The elevation in phagocytic activity could be interpreted in terms of the alteration in the two physiological factors.

Animals↗
PubMed1989

[Induction of phenotypic reverse transformation by plant glycosides in cultured cancer cells].

Crude ginsenosides extracted from the root of Panax ginseng C.A. Meyer inhibited the growth and colony forming ability of Morris hepatoma cells in soft agar suspension culture, and stimulate the serum protein synthesis of these cells, thus converting the cell characteristics both functionally and morphologically to those resembling original normal liver cells. We have called such a phenomenon "reverse transformation" or "redifferentiation" which can be regarded as decarcinogenesis. In this report, the results of our recent investigations are presented with particular reference to reverse transformation of B16 melanoma cells induced by ginsenoside Rh2 isolated from the methanol extract of crude ginseng saponin fraction and action mechanisms of ginsenoside Rh2 are also discussed.

Cell Differentiation↗
PubMed1988

An investigation of the immune suppression induced by some saikosaponin derivatives.

The relationship between lymphocyte activation by purified plant glycoside and the suppression of antibodies against sheep erythrocytes was investigated by an adoptive cell transfer system. Glycosides are one of the main components of Shôsaikotô--famous hematopoietic remedies of oriental medicine. In earlier reports, BALB/c mice treated with these drugs, suppressed the plaque-forming cell (PFC) response to T-dependent antigens. In contrast, the PFC response was enhanced for T-independent antigens. In this communication, an experiment was designed to determine the nature of the suppressive factor(s) produced in treated mice. Mice were orally or intraperitoneally administered 1 mg/kg of five types of purified SS derivatives every other day on five consecutive occasions. Spleen cells and serum were prepared from SS-treated mice and were then passively transferred to recipient mice. On the spleen cells (and not any of the sera) from drug-treated hosts effectively suppressed the PFC in recipients. The spleen cells of treated mice were further divided into adherent and non-adherent cells; each cell type was transferred into recipient animals. The observed suppressive activity was clearly detected in the non-adherent cell population. A subsequent analysis of the lymphocyte subpopulation revealed that Lyt.1.1 negative and Lyt.2.2 positive cells were responsible for this suppression. It was concluded that some SS derivatives elevate the activities of the major immunocyte population, with suppressor cell activity predominating.

Animals↗
PubMed1988

Alterations in the glomerulus in aminonucleoside nephrosis in analbuminemic rats.

Whether obliteration of glomerular epithelial foot processes and increases in urinary N-acetyl-beta-D-glucosaminidase (NAG) activity are the consequence or the cause of proteinuria after administrations of the aminonucleoside of puromycin was examined using Nagase analbuminemic rats. The administration of puromycin aminonucleoside to Nagase analbuminemic rats did not induce proteinuria. However, the increase in urinary NAG activity and the degree of abnormality of foot processes in the glomerular cells were similar to those in control Sprague-Dawley rats. These findings suggest that NAG excretion and the morphological alterations of epithelial cells in nephrosis are not the consequence of massive proteinuria.

Acetylglucosaminidase↗
PubMed1987

Plant-glycoside modulation of cell surface related to control of differentiation in cultured B16 melanoma cells.

We have shown that the ginsenosides Rh1 and Rh2, which are plant glycosides with a dammarane skeleton resembling a steroid skeleton as an aglycone, control the phenotypic expression of mouse B16 melanoma cells in different ways. The effects of Rh1 and Rh2 on the cell surface were studied to clarify the relationship between the control of phenotypic expression and modification of the cell surface in B16 melanoma cells. Rh2, which has the capacity to inhibit the growth of and to stimulate melanogenesis in B16 melanoma cells, causes flattening of the cells cultured in a collagen gel, leading to organized, nonoverlapping monolayers. Cell-to-cell adhesiveness and cell-to-substrate adhesiveness were markedly increased in the B16 melanoma cells treated with Rh2. In Rh2-treated cells, the binding of peanut agglutinin on the cell surface was also increased, whereas no marked changes were observed in the binding of concanavalin A or wheat germ agglutinin. In contrast, Rh1, which showed no effect on cell growth, but did stimulate melanogenesis, did not cause morphological changes of the cells and exerted no effect on cell adhesiveness or cell surface lectin binding. 1,6-Diphenyl-1,3,5-hexatriene polarization values markedly decreased in cells treated with either Rh1 or Rh2. Rh2 was found to be incorporated in the lipid fraction of the B16 melanoma cell membrane. In contrast, Rh1 was not detected in the lipid fraction of B16 melanoma cells. However, novel lipid components were found.

Agglutination↗
PubMed1987

Coefficient of variation in flow cytometry of phagocytosis.

Fluorescence histograms of V79 Chinese hamster lung cells containing phagocytized fluorescent microspheres were measured by flow cytometry. In the fluorescence histograms, the coefficient of variation (CV) of the peak for cells ingesting microspheres was not constant. Rather, it decreased with the number of microspheres ingested by the cells.

Animals↗