Biomedical subjects

I Nakashima

Publications and source records attributed to I Nakashima.

At least 127 records · Page 7Linked to original sources

PubMed1995

Soluble ICAM-1 as a regulator of nasal allergic reaction under natural allergen provocation.

BACKGROUND: Intercellular adhesion molecule-1 (ICAM-1) plays a key role in the early stage of the signal cascade leading to cellular extravasation and development of an inflammatory response. Recently, it has been reported that the soluble form of this adhesion molecule is present in human sera, possibly mediating biological actions. OBJECTIVE: The purpose of this study was to investigate levels of soluble ICAM-1 (sICAM-1) and its receptors in patients with allergic rhinitis, and to discuss sICAM-1's biological function. METHODS: The levels of sICAM-1 in sera and nasal epithelial lining fluids (ELF), the percentage of CD11a-positive lymphocytes in the peripheral blood, and scores of subjective symptoms from 14 patients with pollinosis (allergic group) were measured from pre- to post-season, results were compared with those from 10 non-allergic subjects (control group). RESULTS: The levels of sICAM-1 in sera and ELF were upregulated, and CD11a-positive lymphocytes were downregulated during the in-season in the allergic group. In addition, levels of sICAM-1 sera from the allergic group remained high during the post-season, when levels of other parameters (symptoms, blood eosinophil counts, sICAM-1 in ELF and CD11a-positive lymphocytes) had roughly returned to the initial pre-season levels. CONCLUSIONS: We demonstrate systemic and local upregulation of sICAM-1 and systemic downregulation of LFA-1 positive lymphocytes in patients with seasonal allergic rhinitis under natural allergen provocation, suggesting that sICAM-1 plays a role in regulating seasonal allergic inflammation.

Adult↗

PubMed1995

Promotion of cytotoxic T-cell generation in mixed leukocyte culture by phosphatidylinositol-specific phospholipase C from Bacillus thuringiensis.

Phosphatidylinositol-specific phospholipase C (PIPLC) from Bacillus thuringiensis, which cleaves phosphatidylinositol or glycosylphosphatidylinositol on the external cell surface to generate a second messenger for intracellular signal transduction (S. Rahman et al., FEBS Lett. 303:193-196, 1992), was found to preferentially promote the generation of alloantigen-specific cytotoxic T lymphocytes in mixed leukocyte culture. PIPLC affected an early stage of cytotoxic T-lymphocyte activation in culture, and there was no evidence of any soluble cellular mediators of this PIPLC action. PIPLC neither enhanced overall cell proliferation nor noticeably promoted interleukin-2 and -4 production in mixed leukocyte culture. The relative population size of Ly-2+ T cells was increased, however, in a late mixed leukocyte culture with PIPLC. In addition, PIPLC enhanced an anti-CD3 monoclonal antibody-induced early increase in [Ca2+]i. These results suggest a new parasite (bacterium)-oriented mechanism for enhancing antigen-driven host cytotoxic T-lymphocyte immunity which does not include promotion of interleukin-2 production.

Animals↗

PubMed1995

Enhancement of nitric oxide production from activated macrophages by a purified form of ginsenoside (Rg1).

We studied the actions of purified ginsenosides Rg1 and Rb1 on nitric oxide production from macrophages and a macrophage cell line RAW264-7. Although neither Rg1 nor Rb1 induced nitric oxide from resting macrophages, Rg1 enhanced the production of nitric oxide from IFN-gamma activated-macrophages or RAW cells. Rg1 also enhanced the production of nitric oxide from macrophages cocultured with nonadherent spleen cells stimulated by conA, LPS or anti-CD3. Rb1, however, did not significantly enhance nitric oxide production from stimulated macrophages or RAW cells. Rg1 enhanced the tumor cell killing by nitric oxide produced from IFN-gamma-activated macrophages.

Animals↗

PubMed1994

Gene transfer of TNF receptor for treatment of cancer by TNF.

Tumor necrosis factor-alpha receptors (TNFR-55 and TNFR-75) were inserted into retrovirus derived vector. They were transfected into a packaging cell line. The high titer of transfectants, which produced virus containing TNFR-55 or TNFR-75, was obtained. TNFR-55 and TNFR-75 negative human colon cancer cells were infected with this virus as a model experiment of gene therapy. Although the original colon cancer cell line did not express TNFR-55 or TNFR-75, the colon cancer cells, which were infected by recombinant virus, expressed a high level of TNFR-55 or TNFR-75. TNFR-55 or TNFR-75 transformed colon cancer cells were killed by recombinant TNF.

Cell Line↗

PubMed1994

Kupffer cells cytotoxicity against hepatoma cells is related to nitric oxide.

We have previously demonstrated that rat resting macrophages have cytotoxicity against tumor cells. In the current study we have performed an in vitro experiment to explore the mechanism of Kupffer cells-mediated cytotoxicity against hepatomas. The coculture of tumor cells with Kupffer cells (derived from rat livers) stimulated syngeneic and allogeneic Kupffer cells to produce nitric oxide. Kupffer cell-mediated cytotoxicity was paralleled to the amount of nitric oxide and was abolished by the addition of NG-monomethyl-L-arginine. The ability to stimulate Kupffer cells to produce nitric oxide resided on the membranous fragment of tumor cells.

Animals↗

PubMed1994

Redox mechanism as alternative to ligand binding for receptor activation delivering disregulated cellular signals.

Cross-linking with specific ligand is a general requirement for ordered activation of cell surface receptors. In this study we demonstrated a novel pathway for disregulated receptor activation through a redox mechanism. Treatment of murine thymocytes or spleen cells with thiol-reactive HgCl2, a known inducer of autoimmune proliferative lymphocyte disorders in rodents, was found to induce tyrosine phosphorylation of several cellular proteins, which was up to 100 times as extensive as that triggered by stimulation with antireceptor antibody or mitogen. Through the cross-linkage by thiol-reactive bivalent mercury, transmembrane CD4, CD3, and CD45 and glycosylphosphatidylinositol-anchored Thy-1 were aggregated together on thymocytes or T lymphocytes. Along with the aggregation of Thy-1 and CD4, nonreceptor protein tyrosine kinase p56lck was aggregated and activated. These events were linked to extensive protein tyrosine phosphorylation, which was visualized as a well localized spot beneath the membrane. Under appropriate conditions, this novel pathway of multiple receptor aggregation delivered a disregulated signal into T lymphocytes, which cross-talked to the antireceptor antibody-induced signal, for prolonged cell proliferation and IL-2 production. These results suggest a novel mechanism of disregulation of the ligand-dependent receptor function.

Animals↗

PubMed1994

Expression of nm23 H-1 RNA levels in human gastric cancer tissues. A negative correlation with nodal metastasis.

BACKGROUND: Gene expression of nm23 has been investigated in number of tumors, including breast cancer, colon cancer, malignant melanoma, and hepatocellular carcinoma. Its down-regulation has been shown to be associated with metastasis or disease progression in some of the tumors. METHODS: nm23 H-1 mRNA levels were investigated in 31 surgically resected specimens of gastric cancer by Northern blot analysis, and association with clinical stages was determined. RESULTS: There was no significant difference in nm23 expression between tumor and matching normal mucosa. There was a significant down-regulation of the nm23 gene in gastric cancer with serosal invasion (T3 and T4 by the TNM classification) and nodal metastasis (pN1 and pN2), although the association of the down-regulation with clinically manifest hepatic or peritoneal metastasis was not significant. The tumors with low nm23 expression were associated with a poor prognosis. CONCLUSIONS: It was suggested that the down-regulation of nm23 gene might have a role in metastasis and invasion in gastric cancer, possibly leading to a poor prognosis.

Cell Line↗

PubMed1994

Evidence for posttranscriptional regulation of transgenic protein kinase C-alpha in T cells.

Recently, we succeeded in establishing a transgenic mouse line which expressed high levels of protein kinase C (PKC)-alpha in thymocytes at the mRNA level with disproportionately small increases at the protein level. The transgenic PKC-alpha was nevertheless functionally active for inducing accelerated cell growth and IL-2 production by stimulation with anti-receptor (CD3) antibody or phorbol 12-myristate 14-acetate (PMA) in vitro. Study of the dynamics of transgenic PKC-alpha in the cells in vitro showed that the amount of PKC-alpha protein increased in the cells remarkably at > or = 5 h after stimulation, whereas the level of PKC-alpha mRNA did not change significantly or changed slightly. This suggested that cell activation breaks the posttranscriptional regulation of the transgenic PKC-alpha in resting cells. The increase in PKC-alpha protein accompanied a prolonged membrane translocation of PKC-alpha and enhanced cell proliferation. Such a transgenic effect was inhibited completely by a PKC inhibitor, H-7, added during 0-6 h after the stimulation. These results show formally that the transgenic PKC-alpha whose production was accelerated through cell activation plays a key role in the late (for > or = 5 h) signal delivery for disregulated cell growth.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

PubMed1994

Predominant activation of extrathymic T cells during melanoma development of metallothionein/ret transgenic mice.

Transgenic mice that carried a metallothionein/ret fusion gene (Tg.MT/ret mice) exhibited severe pigmentation in their skin after birth and developed melanomas at adult ages. To learn how the immune system was modulated during melanoma development in these mice, lymphocytes in various organs were examined. An immunofluorescence cell analysis was focused on the simultaneous characterization of T cells of extrathymic and thymic origins and performed at three time points: 6 weeks of age (before melanoma development), 20 weeks (after melanoma development), and 30 weeks (end stage). The number and proportion of extrathymic T cells with TCR of intermediate intensity (i.e., intermediate TCR cells) were markedly increased in the liver over entire periods of life. These intermediate TCR cells constitutively expressed IL-2R beta, contained double-negative CD4-8- cells, and predominated V beta 8+ cells. Such intermediate TCR cells were also abundant among tumor infiltrating lymphocytes. In contrast, an increase in the number and proportion of regular T cells with TCR of bright intensity (i.e., bright TCR cells of thymic origin) was seen at only a limited period in various organs. Rather, at the late phase, thymic atrophy was induced and accompanied with the decrease in the proportion of bright TCR cells in the periphery. These results suggested that extrathymic T cells generated in the liver might play important roles in tumor immunity.

Animals↗

PubMed1994

Characterization of the immunoregulatory action of saikosaponin-d.

The immunoregulatory action of saikosaponin-d (SSd), which was isolated from the root of Bupleurum falcatum L. and has a steroid-like structure, was examined on splenic T lymphocytes of C57BL/6 mice. SSd displayed a definite action in vitro to bidirectionally control the growth response of T lymphocytes stimulated by concanavalin A, anti-CD3 monoclonal antibody, and calcium ionophore A23187 plus phorbol 12-myristate 13-acetate. Low concentrations (1-3 micrograms/ml) of SSd upregulated the responses to suboptimum stimuli of agonists, particularly during the relatively late stage of the responses, whereas it downregulated the responses to supraoptimal stimuli. Under appropriate experimental conditions, SSd promoted interleukin-2 (IL-2) production and IL-2 receptor expression. It also accelerated c-fos gene transcription, but it did not modulate the level of tyrosine phosphorylation of cellular proteins. We concluded from these results that SSd uniquely modulates T lymphocyte function and that at least one target of the action of SSd is located at or before the step of c-fos gene transcription and after T-cell receptor/CD3-mediated protein tyrosine kinase activation.

Adjuvants, Immunologic↗

PubMed1994

Expression of glutathione-S-transferases alpha and pi in gastric cancer: a correlation with cisplatin resistance.

Glutathione-S-transferase (GST) in one of several factors that are proposed to affect tumor sensitivity to anticancer drugs, including cisplatin (CDDP). Attempts are made herein to evaluate the significance of the enzymes in resistance to CDDP in clinical samples of gastric cancer. A total of 22 gastric cancer specimens, 16 of which were obtained with matching normal mucosae, underwent immunoblotting with polyclonal antibodies against GST-alpha and GST-pi. At the same time, the chemosensitivity of 15 gastric cancer specimens to CDDP was evaluated by the succinic dehydrogenase inhibition (SDI) test. The expression of GST-pi was detected in all the specimens, and its content in the neoplasms exhibited a significant positive correlation with that in the matched normal mucosae. The expression of GST-alpha was detected in 18 of 22 cancer specimens (82%), but its content in the neoplasms did not correlate with that in the matched mucosae. A comparison of the drug-sensitivity findings with the results of immunoblotting revealed a weak but interesting correlation between the protein levels of GST-alpha and CDDP resistance. The cellular content of GST-alpha correlated weakly with CDDP resistance in gastric cancer, and its quantification could contribute to prediction of the clinical effects of CDDP in patients with gastric cancer.

Cisplatin↗

PubMed1994

Amniotic fluid enhances allogeneic cytotoxic T cell responses, whereas it suppresses mitogen-stimulated lymphocyte proliferation.

Mouse amniotic fluid has been shown to suppress T lymphocyte proliferation and suggested to be important in regulating immunity during pregnancy. In allogeneic pregnancy, cytotoxic T cells in pregnant lymphocytes against paternal transplantation antigen are impaired. We examined the effect of amniotic fluid to the alloreactive CTL responses. Although the amniotic fluid suppressed Con A or LPS stimulated lymphocyte proliferation as previously reported, the amniotic fluid taken from syngeneic C57BL/6 pregnant mice or allogeneic C57BL/6 x BALB/c pregnant mice enhanced the anti-H-2d or anti-H-2k CTL responses dose-dependently. We speculate that amniotic fluid contains not only immunosuppressive factors but also immunoenhancing factors which upregulate the allogeneic CTL responses.

Amniotic Fluid↗

PubMed1993

The effects of nitric oxide on chondrocytes and lymphocytes.

ConcanavalinA (ConA)-activated lymphocytes markedly induced the production of nitric oxide from chondrocytes. The nitric oxide significantly inhibited the proliferation of both the chondrocytes themselves and the lymphocytes. When culture supernatant from ConA-activated lymphocytes was added to culture of chondrocytes, a large amount of nitric oxide was produced. NG-monomethyl-L-arginine (MMA) significantly eliminated both the production of nitric oxide and the inhibition of chondrocyte and lymphocyte proliferation. Furthermore, when MMA was added to the mixed culture of chondrocytes and lymphocytes with ConA, their proliferation was markedly enhanced compared with individual summation. These results indicate that chondrocytes produce not only nitric oxide but also a lymphocyte stimulating factor, the effects of which are, however, usually masked by the nitric oxide.

Animals↗

PubMed1993

Pathway of signal delivery to murine thymocytes triggered by co-crosslinking CD3 and Thy-1 for cellular DNA fragmentation and growth inhibition.

The signal delivery pathway triggered by crosslinking CD3 and Thy-1 together (CD3/Thy-1 crosslinkage) on murine thymocytes for cellular DNA fragmentation/growth inhibition was analyzed. The treatment of thymocytes with herbimycin A as a specific tyrosine kinase inhibitor under suboptimum conditions before the CD3/Thy-1 crosslinkage partially but preferentially inhibited the otherwise promoted tyrosine phosphorylation of p40 and p56. Evidence was then provided that acceleration of the kinase activity of p56lck was involved in the CD3/Thy-1 crosslinkage-triggered signal. Partial characterization of p40 distinguished it from the p43 and p41 MAP kinases, the tyrosine phosphorylation of which was only marginally accelerated. Promotion of DNA fragmentation by the CD3/Thy-1 crosslinkage-triggered signal was actually ablated by the treatment with herbimycin, suggesting the obligatory involvement of the herbimycin highly sensitive kinase activity in the signal pathway. The signal induced by co-crosslinkage of CD3 and Thy-1 was also shown to be negatively biased against mature T lymphocytes, suppressing their CD3-mediated growth response. The negative signal was then found to partially attack the process of c-fos transcription as an earlier nuclear event. Interestingly, this c-fos suppression was prevented by the treatment of thymocytes with herbimycin before stimulation, for accelerated expression of c-fos. It is suggested from these results that the CD3/Thy-1 crosslinkage delivers protein tyrosine kinase-dependent negative signaling for inhibition of early and late nuclear events of both immature thymocytes and mature T lymphocytes.

Animals↗

PubMed1993

Higher expression of topoisomerase II in lung cancers than normal lung tissues: different expression pattern from topoisomerase I.

To examine the expression of topoisomerase I and topoisomerase II in primary lung cancer specimens at mRNA level, we carried out Northern blot analysis. As for topoisomerase I expression, there was no remarkable difference between lung cancer specimens and non-cancerous lung tissues. On the other hand, we could detect topoisomerase II mRNA in almost all lung cancer specimens, but not in non-cancerous tissues. By Southern blot analysis, we could not detect large deletion nor rearrangement in DNA level. These results suggest that the expression of topoisomerase II is highly increased in lung cancer at mRNA level and drugs against topoisomerase II might be more tumor-specific than those against topoisomerase I.

Adenocarcinoma↗

PubMed1993

Abundant production of nitric oxide from murine macrophages by direct stimulation of tumor cells.

By the coculture of tumor cells and resident murine peritoneal macrophages, we found that P1HTR tumor cells, which were the subline of P815 mastocytoma, stimulated syngeneic or allogeneic peritoneal macrophages to produce nitric oxide. This nitric oxide in turn kills P1HTR target cells. The cytotoxicity and nitric oxide production were completely abolished by the addition of L-arginine homologue NG-monomethyl-L-arginine. The original P815 tumor cells had only weak activity to stimulate macrophages to produce nitric oxide and were weekly killed by coculture of P815 and resident macrophages. Macrophage cell line, RAW264-7, was also stimulated to produce nitric oxide by P1HTR cells. The ability to stimulate macrophages to produce nitric oxide resided on the membranous fragment of P1HTR cells.

Animals↗

PubMed1993

Redox-linked ligand-independent cell surface triggering for extensive protein tyrosine phosphorylation.

Exposure of lymphocytes to 0.2-2 mM HgCl2, a thiol-reactive heavy metal, induced extensive tyrosine phosphorylation of multiple cellular proteins. The phosphorylation started as quickly as 5 s after exposure to HgCl2, and was irreversible. Another 3 thiol-reactive chemicals also displayed similar, though less marked, actions, whereas dithiothreitol, a reducing agent, antagonized the HgCl2 action. The demonstrated new action of HgCl2 indispensably required membrane-intact cells as a target. Whereas exposure of lymphocytes to > 0.2 mM HgCl2 caused rapid cell death, 0.01-0.1 mM HgCl2 affected the cells so as to accelerate their c-fos transcription. These results suggest a novel redox-linked mechanism of cell surface triggering of intracellular protein kinase activity, which is independent of receptor-ligand interactions.

4-Chloromercuribenzenesulfonate↗

PubMed1993

Nitric oxide production from a macrophage cell line: interaction with autologous and allogeneic lymphocytes.

The indirect stimulation of macrophages to produce nitrite was examined by using the macrophage cell line J774.J774 spontaneously produced nitrite, when cultured at high concentration. J774 cultured in low concentration (< 10(4) cells in 100 microliters) barely produced nitrite. J774 cultured in low concentration produced a large amount of nitrite by the co-culture of nonadherent spleen cells or nonadherent peritoneal exudate cells, which were stimulated with con A, anti-CD3, or staphylococcal enterotoxin A. J774 (BALB/c derived: H-2d) cultured with either syngeneic (BALB/c) or allogeneic (B6; H-2b B10BR; H-2k) nonadherent lymphocytes, which were stimulated with conA or anti-CD3, produced nitric oxide. However, J774 produced nitric oxide by stimulation with SEA only when co-cultured with SEA-reactive T lymphocytes. Peritoneal exudate cells from mice, which did not proliferate by the stimulation of conA or anti-CD3, proliferated well by the addition of L-arginine homologue, NG-monomethyl-L-arginine. The proliferation of nonadherent peritoneal exudate cells stimulated with conA or anti-CD3 was suppressed by the addition of peritoneal macrophages. This suppression was abolished by the addition of NG-monomethyl-L-arginine.

Animals↗