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Biomedical subjects

R Shirakura

Publications and source records attributed to R Shirakura.

At least 91 records · Page 5Linked to original sources
PubMed1997

Granulocyte colony-stimulating factor and interleukin-6-producing lung cancer cell line, LCAM.

BACKGROUND AND OBJECTIVES: We describe a case of granulocyte colony-stimulating factor (GCSF) and interleukin-6 (IL-6)-producing lung cancer. METHODS: A 53-year-old man underwent left upper lobectomy under diagnosis of lung cancer. The tumor obtained by a preoperative biopsy was analyzed. RESULTS: Preoperative data showed leukocytosis with left-shift of leukocytic morphology and thrombocytosis and an elevated serum GCSF level. Histological examination revealed poorly differentiated adenocarcinoma. A cell line, named LCAM, was established from the tumor and the cytokines in the culture medium were measured by enzyme immunoassay. GCSF and IL-6 were produced in large amounts by LCAM, but granulocyte-macrophage colony-stimulating factor (GMCSF) and interleukin-3 (IL-3) were not. A proportion of LCAM expressed GCSF receptor on the cell surface, but IL-6 receptor could not be detected. LCAM proliferation was inhibited in the culture with antihuman GCSF antibody in a dose-dependent manner. CONCLUSIONS: We suggest that LCAM proliferation is positively regulated by GCSF.

Granulocyte Colony-Stimulating Factor↗
PubMed1997

The contribution of Na+/H+ exchange to ischemia-reperfusion injury after hypothermic cardioplegic arrest.

BACKGROUND: Na+/H+ exchange has been reported to be one of the key mechanisms in myocardial ischemia-reperfusion injury. However, the effect of temperature on Na+/H+ exchange is not fully understood. METHODS: Sodium-propionate-induced cell swelling, an indicator of the function of the Na+/H+ exchanger, was measured in rat thymic lymphocytes. A Langendorff perfused rat heart model was also employed to investigate the effect of the pharmacologic inhibition of Na+/H+ exchange on the recovery of cardiac function after hypothermic ischemia. This was done using FR168888, an inhibitor of Na+/H+ exchange. RESULTS: In the in vitro study, rat lymphocytes were observed to swell at 17 degrees, 22 degrees, and 27 degrees C, indicating that the Na+/H+ exchanger remains functional even under hypothermic conditions. FR168888 was found to significantly inhibit Na+/H+ exchange-induced cell swelling, even at 17 degrees C. In the in vivo study, pretreatment with FR168888 was found to prevent the deterioration of ventricular function, even after 5 hours of hypothermic cardioplegic arrest. This was associated with a decrease in the reperfusion-induced elevation in resting tension. CONCLUSIONS: These results suggest that Na+/H+ exchange in the heart still occurs, even under hypothermic conditions, and contributes to reperfusion injury, even after hypothermic cardioplegic arrest.

Animals↗
PubMed1997

Experimental bronchiolitis obliterans induced by in vivo HVJ-liposome-mediated endothelin-1 gene transfer.

BACKGROUND: Bronchiolitis obliterans (OB) is a lesion that results when injury to small conducting airways is repaired by a proliferation of fibrous granulation tissue. Bronchiolitis obliterans has emerged as a main cause of morbidity and mortality in the setting of lung and heart-lung transplantation. Endothelin-1 (ET-1), initially discovered as a vasoconstrictive peptide, has a mitogenic activity on vascular smooth cells and airway epithelial cells. Overproduction of endothelin has been reported in patients with OB or chronic rejection after lung transplantation. It is still undetermined whether locally overexpressed ET-1 has a potential impact in the pathogenesis of OB. METHODS: We locally overexpressed ET-1 using ultraviolet irradiation-inactivated hemagglutinating virus of Japan (HVJ)-liposome-mediated in vivo gene transfer. Plasmid DNA of prepro-ET-1 and high mobility group 1 protein were coencapsulated in liposomes, and were introduced into airway epithelial cells by HVJ-mediated membrane fusion. Control animals received instillation of HVJ-liposome with an empty expression cassette. To confirm the efficiency of transfection, HVJ liposome with beta-galactosidase gene was introduced. The expression of ET-1 and beta-galactosidase was assessed by immunohistochemistry. RESULTS: Bronchial epithelium alveolar cells and alveolar macrophage were stained blue (X-Gal) 1 week after in vivo gene transfer of beta-galactosidase gene, indicating beta-gal activity. In animals 1 to 2 weeks after in vivo transfection of prepro-ET-1 gene, hyperplastic connective tissue plaque was seen in the alveolar duct and small conducting airway, indicating histologically distinctive bronchiolitis obliterans. Strong ET-1-like immunoactivities were seen in the airway epithelial, hyperplastic connective tissue, and alveolar cells. No histopathologic changes were seen in the control animals. CONCLUSIONS: These results suggested that ET-1 may play an important role in the pathogenesis of OB. The effective pharmacologic antagonist or inhibitor may possibly control the progression of disease in patients of OB.

Animals↗
PubMed1997

Increased nitric oxide levels in exhaled air of rat lung allografts.

In organ transplantation nitric oxide has been reported to be involved in allograft rejection. We examined in a rat lung transplantation model whether nitric oxide is overproduced in acute rejection and can be detected in exhaled air. Thirteen rat right lung transplants were separated into three groups: group 1 (n = 5), untreated allografts (Brown-Norway [RT1n] to Lewis [RT1l]); group 2 (n = 4), cyclosporine-treated allografts; and group 3 (n = 4), isografts (Lewis to Lewis). We examined exhaled nitric oxide levels with a chemiluminescence analyzer and chest roentgenograms on days 2 through 5. Histologic samples were obtained on days 3 and 5. On day 5, the recipients were killed and we measured exhaled nitric oxide from the right and left lungs separately. Blood samples were also obtained for measurement of serum nitrite/nitrate. The exhaled nitric oxide level in untreated allografts increased significantly from day 5 (63.9 +/- 39.2 ppb, p = 0.0095) and was significantly higher than that in treated allografts (9.1 +/- 1.6 ppb) (p = 0.0085) and isografts (6.9 +/- 0.5 ppb) (p = 0.0068). The nitric oxide level in untreated allografts (826.5 +/- 416.1 ppb) was 75 times as high as that from the contralateral normal left lungs (11.2 +/- 2.6 ppb) (p = 0.0118). The level of exhaled nitric oxide correlated significantly with the histologic rejection grade (p = 0.0001). There was no significant difference in the serum nitrite/nitrate levels between allografts and isografts. These data suggest that increased exhaled nitric oxide levels might reflect acute rejection in lung transplants.

Animals↗
PubMed1997

Efficient gene transfer method into the whole heart through the coronary artery with hemagglutinating virus of Japan liposome.

OBJECTIVE: To confirm gene transfer techniques especially into the whole heart, we tried out a gene transfer method involving liposome with the viral envelope hemagglutinating virus of Japan liposome as an alternative to existing techniques such as cationic lipofection or other viral vectors. METHOD: For this study, hemagglutinating virus of Japan liposome (H group) or cationic liposome (L group) was used to compare the efficacy of gene transfection of oligonucleotide labeled with fluorescein isothiocyanate and cDNA of beta-galactosidase and human manganese-superoxide dismutase. Fluorescein-labeled oligonucleotide, cDNA of beta-galactosidase, or manganese-superoxide dismutase was complexed with liposomes, DNA-binding nuclear protein, and the viral protein coat of hemagglutinating virus of Japan. After donor rat hearts arrested by cardioplegia had been harvested, the coronary artery during cardioplegic arrest was infused via an aortic cannula with the liposome-gene complex. Next, the hearts were transplanted into the abdomen of recipient rats of the same strain, and all recipients were put to death after 3 days of transfection. RESULTS: Fluorescein isothiocyanate was detected in the nuclei of more than 70% of the myocytes (75% +/- 14%, n = 5) in the H group compared with fewer than 10% in the L group (7% +/- 5%, n = 5). The intensity of fluorescein isothiocyanate was significantly higher in the H group (979 +/- 112 FI) than in the L group (116 +/- 68 FI). beta-Galactosidase was expressed in the cytosol of more than 50% of the myocytes in the H group (61% +/- 7%, n = 5) compared with none in the L group (0%, n = 5). After 3 days of gene transfection, and when exposed to ischemia (30 minutes, 37 degrees C) and reperfusion (30 minutes, 37 degrees C) with Langendorff apparatus, the hearts transfected with manganese-superoxide dismutase (S group, n = 5) showed a significantly higher percentage of recovery of left ventricular end-diastolic pressure (S vs C, 86% +/- 3% vs 54% +/- 12%) and coronary flow (98% +/- 2% vs 66% +/- 12%) than did the control hearts (C group, n = 5). Western blotting analysis showed an apparent increased expression of manganese-superoxide dismutase in the hearts transfected with manganese-superoxide dismutase compared with the control hearts. These results clearly demonstrated that the donor hearts were transfected with fluorescein-labeled oligonucleotide and the beta-galactosidase gene as a result of coronary infusion of the hemagglutinating virus of Japan liposome during cardioplegic arrest at the time of harvest. Furthermore, the hearts transfected with manganese-superoxide dismutase showed significant improvement in tolerance against ischemia reperfusion injury. CONCLUSION: We believe that this method represents a novel in vivo gene transfer technique for the heart and thus may provide a new tool for research and therapy of heart transplantation.

Animals↗
PubMed1997

Essential initial immunostimulation in graft coronary arteriosclerosis induction detected by retransplantation technique in rats: the participation of T cell subsets.

Graft coronary arteriosclerosis occurs as chronic rejection after heart transplantation. In the previous studies, we have examined the minimum period of allogeneic stimulation to induce this change, using heterotopic rat heart transplantation and a retransplantation model. Retransplantation of allografts back into the donor strain did not prevent graft arteriosclerosis if the grafts had resided in the primary recipient for up to five days. In this study, the participation of the T cell subset causing graft coronary arteriosclerotic change was assessed using the same model. The transplanted rats in fully allogeneic or non-MHC antigen mismatch combinations were treated with a short-course administration of FK506. The graft was removed and retransplanted into the donor strain rats to escape from further immunological stimulation. CD4+ T cells and/or CD8+ T cells of first recipient rats in both combinations were eliminated by monoclonal antibodies. The grade of arteriosclerosis in the retransplanted hearts was evaluated on a basis of a scale from 0-4 according to the histological appearance of the vessel injury on day 40 after initial engraftment. While neither anti-CD4 nor anti-CD8 monoclonal antibody alone had little effect, the administration of both mAbs reduced this arteriosclerotic change and development. In conclusion, the T cell subsets, CD4+ T cell and CD8+ T cell play a certain role in the induction of the graft coronary arteriosclerotic change.

Animals↗
PubMed1997

Mature CD4 single positive thymocytes in human Thymoma: T cells may differentiate in the thymic epithelial cell tumor.

Human thymoma, which is occasionally associated with autoimmune disease, is a thymic epithelial cell tumor and often contains a large number of lymphocytes. In a previous study, we have shown that a proportion of CD4 single positive T cells in human thymomas lack CD3, suggesting immaturity. In this study, we focused on the rest of the CD4 single positive T cells in thymomas that expressed CD3/TcR alpha beta and investigated the maturity of single positive T cells by analyzing lymphocyte surface antigens and the cells' proliferative response to a mitogen. CD4 single positive cells that expressed CD3 or TcR alpha beta also expressed CD69 and had probably undergone positive selection in the tumor. Further, isolated CD4 or CD8 single positive cells from the thymomas responsed to a mitogen although at lower levels than the corresponding single positive cells in the peripheral blood. These results indicate that thymomas contain single positive T cells which have mature phenotype and proliferative ability, and suggest that T cells may differentiate in thymoma.

Adult↗
PubMed1996

Late true aneurysm after bypass grafting for long aortic coarctation.

Two adolescent patients who underwent a repair of long aortic coarctation using bypass grafting with subsequent late true aneurysm formation are reported. To our knowledge, only 1 case of late true aneurysm formation after bypass grafting has been reported in the English-language literature.

Adolescent↗
PubMed1996

C5b-8 step lysis of swine endothelial cells by human complement and functional feature of transfected CD59.

The authors established several swine endothelial cell (SEC) lines expressing human CD59 by transfection of cDNA, and assessed the function of the transfectant molecules in comparison with those of membrane cofactor protein (MCP) and decay-accelerating factor (DAF) in an in vitro hyperacute rejection model of swine to human discordant xenograft. At the usual expression rate, DAF and MCP protected SEC from human complement mediated cell lysis, but CD59 did not block human complement attack on SEC. However, CD59 protects SEC from cell lysis when sufficiently expressed as in human umbilical vein (HUVEC). The authors examined why CD59 needed so many molecules to protect human complement-mediated SEC lysis and found that SEC underwent lysis by human C5b-8. The degree of C5b-8 step lysis of SEC was approximately 70% of the total activation (C5b-9). Additionally, CD59 protected human complement activities less efficiently at the C5b-8 step than at the C9-step. Therefore, to overcome human complement mediated SEC lysis, C8 activity must be inhibited by dense expression of CD59.

Animals↗
PubMed1995

Evidence that graft coronary arteriosclerosis begins in the early phase after transplantation and progresses without chronic immunoreaction. Histopathological analysis using a retransplantation model.

The histopathological features of chronic rejection and its initiation were assessed using rat heterotopic heart transplantation and retransplantation models. Fully allogeneic or minor, non-MHC antigen-mismatch heart grafts transplanted into recipient rats treated with a short course of FK506 showed long-term survival but developed graft atherosclerosis after 40 days posttransplantation. Retransplantation of allografts back into the original donor strain did not prevent graft atherosclerosis if the grafts had resided in the primary recipient for up to 5 days; residence in the primary allogeneic recipient for less than 4 days did not result in graft atherosclerosis in the secondary recipient. Short-course administration of FK506 did not affect the production of these changes. Graft coronary arteriosclerosis begins between 3 and 5 days posttransplantation and progresses without continuous allogeneic immunological drive. The present findings will provide a new means by which to approach the analysis of development of chronic allograft rejection.

Animals↗
PubMed1995

Efficiency of in vivo gene transfection into transplanted rat heart by coronary infusion of HVJ liposome.

BACKGROUND: Current methods of in vivo gene transfer into myocardium are limited by low efficiency. To improve in vivo gene transfer, a gene transfer method using hemagglutinating virus of Japan (HVJ) as a viral vector can be an alternative. METHODS AND RESULTS: In vivo gene transfection of FITC-labeled oligonucleotide (F-ODN) and cDNA of beta-galactosidase (beta-gal) was examined with use of the HVJ liposome (H group) or without it (C group). In the H group, F-ODN or cDNA of beta-gal were complexed with liposomes, DNA binding nuclear protein (HMG1), and the viral protein coat of HVJ. After the harvest of donor rat hearts arrested by cardioplegia, the coronary artery was infused with the liposome gene complex. The hearts were transplanted into the abdomens of recipient rats and harvested 3 days after transplantation. Regarding F-ODN, the H group clearly showed FITC staining in the nuclei of the myocytes and endothelial cells in almost all layers of the myocardium as compared with the C group. Regarding the expression of beta-gal, the H group showed a clear expression of beta-gal on myocytes, whereas very low expression of beta-gal was seen in the C group. CONCLUSIONS: The donor hearts were transfected with F-ODN and beta-gal gene in almost all layers of the myocardium as a result of coronary infusion of the HVJ liposome during cardioplegic arrest. Our method is seen as a novel in vivo gene transfer technique for the heart and may provide a new tool for both research and therapy of heart transplantation.

Animals↗
PubMed1995

Inhibition of Na+/H+ exchanger attenuates neutrophil-mediated reperfusion injury.

BACKGROUND: The effect of Na+/H+ exchange inhibition in neutrophil-induced reperfusion injury was investigated using a new amiloride analogue, 5-methyl-N-isobutyl amiloride (MIA). METHODS: Rat neutrophils were separated using Percoll gradient. Luminol chemiluminescence intensity of isolated neutrophils was depressed by MIA in a dose-dependent manner. RESULTS: The effect of MIA on neutrophil-induced reperfusion injury was evaluated in Langendorff-perfused rat hearts subjected to 30 minutes of normothermic ischemia. Postischemic left ventricular developed pressure recovery was depressed by the reperfusion with neutrophils (60% +/- 7% to 33% +/- 26%) and was reverted by MIA pretreatment (86% +/- 17%, p < 0.05). MIA also improved percent recovery of coronary flow (51% +/- 2% to 70% +/- 13%), reduced creatine kinase (0.28 +/- 0.1 to 0.085 +/- 0.03 IU.L-1.g-1 dry wt), and lactate dehydrogenase leakage (10.6 +/- 3.8 to 5.16 +/- 1.3 IU.L-1.g-1 dry wt) significantly. The incidence of reperfusion-induced ventricular fibrillation also was reduced by MIA. CONCLUSIONS: The inhibition of Na+/H+ exchange shows a protective effect against neutrophil-induced reperfusion injury possibly by inhibiting the activation of neutrophils.

Amiloride↗