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Biomedical subjects

T Inamoto

Publications and source records attributed to T Inamoto.

At least 37 records · Page 2Linked to original sources
PubMed1999

Reduction of BRCA1 protein expression in Japanese sporadic breast carcinomas and its frequent loss in BRCA1-associated cases.

BRCA1 is a tumor suppressor gene that is responsible for hereditary breast and ovarian cancer syndrome. To clarify the possible involvement of the BRCA1 protein in mammary carcinogenesis in sporadic and hereditary forms, we have analyzed the BRCA1 protein expression pattern in five breast epithelial cell lines, including a BRCA1-deficient cell line, and 162 breast cancer tissue samples [including 108 sporadic, 35 hereditary (BRCA1 status unknown), and 19 BRCA1-associated cases] from Japanese women. Twelve anti-BRCA1 antibodies were tested by fixation conditions, in which nuclear localization of BRCA1 protein was preserved, and by specificity of the antibodies, which was evaluated in BRCA1-deficient cancer cells. Using monoclonal antibodies applicable to immunohistochemical analysis of paraffin-embedded tissue sections, we found high-level expression of BRCA1 protein in normal mammary epithelium and various degrees of reduced expression in breast cancer cells. Of the 19 BRCA1-associated breast cancer tissues, 15 (79%) showed reduction (8 cases) or complete loss (7 cases) of nuclear expression. Thirty (28%) of 108 sporadic and 6 (17%) of 35 hereditary carcinomas showed reduced BRCA1 protein expression. Reduction of BRCA1 protein expression in sporadic carcinomas was associated with solid-tubular phenotype, with poor tubular differentiation, and with an overexpression of c-erbB-2 protein, which is one of the prognostic factors in breast cancer. Our data suggest that reduced expression of BRCA1 protein may play an important role in mammary carcinogenesis, not only in BRCA1-associated breast carcinomas, but also in sporadic carcinomas, and also suggest that mechanisms other than mutation may be involved in its reduced expression.

Animals↗
PubMed1998

Possible availability of N-acetylcysteine as an adjunct to cytokine therapy for hepatocellular carcinoma.

To examine the possibility of immunotherapy for activating liver-associated mononuclear cells (liver MNC) in hepatocellular carcinoma (HCC), we evaluated the cytotoxicity of liver MNC and peripheral blood mononuclear cells (PBMNC) in HCC patients and examined how they can be activated by cytokines and how this activation is modulated by reduction/oxidation. Cytotoxicity of liver MNC but not PBMNC in HCC patients was significantly decreased compared with that of controls, despite no alteration in the subpopulation of liver MNC between the two groups. We next measured intracellular glutathione (GSH), which is required for the enhancement of the cytotoxicity by interleukin-2 (IL-2). Intracellular GSH levels of liver MNC in HCC were significantly lower than that of controls. In vitro administration of N-acetylcysteine (NAC) not only restored intracellular GSH levels but also enhanced the IL-2-stimulated cytotoxicity of liver MNC in HCC patients. This suggests that intracellular GSH of liver MNC in HCC may participate in the modulation of cytotoxicity of liver MNC in vitro and that NAC may be effective as an adjunct to immunotherapy for HCC.

Acetylcysteine↗
PubMed1998

Exposure of hepatic sinusoidal mononuclear cells to UW solution in situ but not ex vivo induces apoptosis.

BACKGROUND/AIMS: We have previously reported that human hepatic sinusoidal mononuclear cells may have a higher sensitivity to induction of apoptosis than peripheral blood mononuclear cells. In this study, the effects of two different preservation solutions on the functions of those hepatic mononuclear cells were evaluated in living-related liver transplantation. METHODS: Ten and 11 liver grafts were perfused via the portal vein with University of Wisconsin solutions (UW group) and Bretschneider's Histidine-Tryptophan-Ketoglutarate solutions (HTK group), respectively. Hepatic mononuclear cells were isolated from the effluent preservation solution passing through the graft livers. Cytofluorometry, cytotoxic assay, and DNA analysis were performed. RESULTS: There were no significant differences in surface antigens and natural killer activity of hepatic sinusoidal mononuclear cells between the UW and HTK groups. At the time of isolation, the viability of hepatic sinusoidal mononuclear cells in both groups was more than 99%. In the UW group, the viability of hepatic sinusoidal mononuclear cells decreased to 30% through apoptosis in in vitro culture at 48 h after isolation. In the HTK group, however, their viability was maintained at more than 90% at 48 h in the same culture conditions, and additional exposure to UW solution ex vivo for 30 min did not induce apoptosis. CONCLUSION: Hepatic sinusoidal mononuclear cells isolated from the UW solution, not from the HTK solution, passing through the liver died through apoptosis, which was not induced by each component of the UW solution, but by exposure in situ.

Adenosine↗
PubMed1998

N-acetylcysteine improves cytotoxic activity of cirrhotic rat liver-associated mononuclear cells.

Liver cirrhosis, which is associated with decreased plasma and hepatic glutathione (GSH), has been reported to cause the suppression of NK activity in peripheral blood mononuclear cells. Since low GSH levels in lymphocytes are known to alter lymphocyte function, we examined the correlation between intracellular GSH levels and the cytotoxic activity of liver-associated mononuclear cells (liver MNC). We show here that rat liver contains a highly active population of NK cells (CD3- NKR-P1 + cells) that kill Yac-1 in vitro and that the cytotoxic activity of this NK population is directly proportional to liver MNC GSH. This proportionality is independent of the methods used to alter GSH level. Thus, in vitro treatment of liver MNC with buthionine sulfoximine to lower GSH levels lowers the cytotoxic activity. MNC from cirrhotic liver, in which implanted tumor cells grow faster, have both low GSH levels and low cytotoxicity, and supplementation of cirrhotic liver MNC with N-acetylcysteine raises GSH levels and increases cytotoxicity. These findings suggest a physiologic mechanism, i.e. decreased GSH, may be causally associated with the increased incidence of hepatoma in cirrhotic individuals and the increased growth of hepatoma cells in cirrhotic animals. Thus, we suggest that the GSH is important to the optimal functioning of the hepatic immunity that protects against hepatoma development.

Acetylcysteine↗
PubMed1998

Antitumor activity of alpha-galactosylceramide, KRN7000, in mice with EL-4 hepatic metastasis and its cytokine production.

Liver metastasis of primary tumor is a clinically major problem. KRN7000, an alpha-galactosylceramide, significantly augments natural killer (NK) activity of spleen cells and shows strong antitumor activity in mice with lung metastasis of melanoma B16 cells. To test whether KRN7000 has an antitumor activity in mice with hepatic metastasis of tumors, we examined the effect of KRN7000 on NK activity of hepatic mononuclear cells (MNC) and the antitumor activity in mice with liver metastasis of EL-4 cells. The in vivo administration of KRN7000 significantly augmented NK activity of hepatic MNC and inhibited tumor growth of EL-4 cells in the liver more markedly than chemotherapeutic agents, leading to a relatively high rate of cured mice. In addition, it appeared that the KRN7000 treatment is effective in mice with established EL-4 tumors. Moreover, we found that KRN7000 can produce significant amounts of interleukin 2 (IL-2), IL-4, IL-12, and interferon-gamma in a dose-dependent manner. These results suggest that KRN7000 will be useful for the treatment of cancer liver metastasis.

Animals↗
PubMed1997

Presence of anti-FKBP12 autoantibodies in patients with liver allografts: its association with allograft rejection.

BACKGROUND: It was reported that autoantibodies against cyclophilin are present in sera from systemic lupus erythematosus. We hypothesized that autoantibodies against FKBP12, another immunophilin, may be present in the plasma of liver allograft recipients, which may affect the clinical outcome of liver allografts. METHODS: We investigated the relationship between the presence of anti-FKBP12 autoantibodies and rejection episodes in 47 patients treated with FK506 after living-related partial liver transplantation (LRLT). The patients consisted of two groups: 22 with rejection [R(+) group] and 25 without rejection [R(-) group]. The autoantibodies were measured by an indirect ELISA, and the specificity was confirmed by absorption with antigen and immunoblotting. RESULTS: The autoantibodies were detected in 13 of 22 in the R(+) group (IgG: 5; IgM: 6; both: 2) and in 6 of 25 in the R(-) group (IgG: 2; IgM: 3; both: 1) before LRLT (P=0.0193). After LRLT, they were also detected more frequently in the R(+) group (12 of 22; IgG: 1; IgM: 8; both: 3) than in the R(-) group (2 of 25; IgG: 1; IgM: 1) (P=0.001). In the R(+) group, the mortality of the patients who were positive and negative for the autoantibodies was 6 of 12 and 2 of 10, respectively. The autoantibodies were detected in all four patients with chronic or refractory acute rejection. The autoantibodies were not detected in any of the 34 healthy subjects. CONCLUSIONS: These results suggest that the presence of the autoantibodies in patients before transplantation is related to rejection, and the presence after transplantation may be associated with patient outcome.

Absorption↗
PubMed1997

Role of intracellular redox status in apoptosis induction of human T-cell leukemia virus type I-infected lymphocytes by 13-cis-retinoic acid.

We have shown that cell cycle progression of human T-cell leukemia virus type I (HTLV-I)-transformed T-cell lines was inhibited by 13-cis-retinoic acid (13cRA). In the present study, we report that 13cRA inhibited proliferation and induced cell death of peripheral blood mononuclear cells obtained from four patients with acute adult T-cell leukemia but not of mitogen- or interleukin 2-activated peripheral blood mononuclear cells from HTLV-I-negative healthy donors. Because HTLV-I-infected lymphocytes are susceptible to oxidative stress, we examined the role of the intracellular redox state in 13cRA-induced cell death using a HTLV-I-positive T-cell line, ATL2, as a model. 13cRA induced apoptosis in ATL2 cells within 48 h in a dose-dependent manner. The ability of 13cRA to induce apoptosis was more potent than that of all-trans-retinoic acid. Apoptosis induction by 13cRA was significantly enhanced by buthionine sulfoximine (BSO), which decreased the levels of intracellular reduced glutathione, although 13cRA by itself did not alter them, suggesting that intracellular reduced glutathione may modulate 13cRA-induced apoptosis. In addition, flow cytometric analysis revealed that 13cRA increased intracellular peroxides in 24 h and that the addition of BSO further enhanced them. Although N-acetylcysteine had only a marginal effect, pretreatment with catalase markedly inhibited 13cRA-induced apoptosis. These results suggest that peroxide generation, ie., oxidative stress, may play a crucial role in the induction of apoptosis by 13cRA and further demonstrate that combined treatment with 13cRA and BSO induces apoptosis of HTLV-I-positive lymphocytes even more potently.

Adult↗
PubMed1997

Successful long-term xenoperfusion of the pig liver: continuous administration of prostaglandin E1 and insulin.

For clinical utilization of extracorporeal liver perfusion as an artificial liver assist device, we examined the possibility of long-term xenoperfusion of the pig liver by the continuous administration of prostaglandin E1 (PGE1) and insulin. After a 3-hr perfusion period, pig livers that were xenoperfused with human blood exhibited a drastic decrease in the perfusate volume, a progressive elevation of the hepatic artery pressure, a gradual deterioration of bile production, and a marked increase in the release of creatine kinase-BB component. The continuous administration of PGE1 (25 microg/hr) and insulin (1 U/hr) significantly improved these derangements (P<0.05) and allowed stable perfusion for up to 9 hr. This manipulation also inhibited leukocyte aggregation in the graft, the characteristic perfusate hemolysis, and acceleration of ketogenesis. Histological examination revealed that the interlobular edema and hemorrhage, characteristics of tissue injuries in xenogeneic hyperacute rejection, were markedly alleviated in the PGE1 and insulin-treated group. This study clarifies the finding that the combined administration of PGE1 and insulin is effective for long-term xenogeneic extracorporeal liver perfusion, with the graft viability well maintained.

Alprostadil↗
PubMed1997

The protective effects of prostaglandin E1 on sinusoidal endothelial cells in xenogeneic pig liver perfusion.

The effects of prostaglandin E1 (PGE1) on hepatic sinusoidal endothelial cells (SEC) in the xenogeneic immunoreaction were investigated. Porcine livers were perfused with fresh human blood via the portal vein (PV) and the hepatic artery (HA) either with the administration of PGE1 (Group PG) or without PGE1 (Group C). The creatine kinase-BB component (CK-BB) in the perfusate was measured to assess SEC damage. SEC activation and complement activation were evaluated immunohistochemically by the expression of von Willebrand factor (vWF) and by the deposition of membrane attack complex (MAC), respectively. Xenoperfusion in Group C was discontinued between 4 and 6 hr due to the rapid elevation of HA pressures and the massive loss of perfusate. In Group PG, both PV and HA pressures were kept stable for up to 9 hr. In Group C, severe interlobular bleeding and diffuse extrasinusoidal hemorrhage were observed at 4 hr histologically, while in Group PG, the hepatic architecture was maintained without hemorrhage at 6 hr. MAC was markedly deposited on SEC and parenchymal cells at 3 hr in both groups. The amount of vWF, however, was expressed on SEC in large amounts at 1 hr in Group C, while small amounts were expressed at 1 hr in Group PG. In Group PG, CK-BB release was significantly lower than in Group C (P < 0.01). These results suggest that PGE1 suppressed SEC activation and protected the impairment of hepatic SEC during xenoperfusion without suppressing complement activation, resulting in the prolongation of xenogeneic liver perfusion.

Alprostadil↗
PubMed1997

Reducing environment protects sinusoidal lymphocytes isolated from normal human liver from apoptosis.

BACKGROUND/AIMS: We previously reported that the populations of lymphocytes and the expression of activated antigens in human sinusoidal mononuclear cells were different from those in peripheral blood mononuclear cells. Attempts to culture these cells for further study failed because they died rapidly under standard culture conditions in vitro after isolation from the liver. In this study, we evaluated the characteristics of cell death and the effects of various culture conditions on the viability of these cells. METHODS: Sinusoidal mononuclear cells were isolated from University of Wisconsin solution that had been perfused through the portal veins of normal healthy human livers harvested for transplantation into living related recipients. RESULTS: 70% of sinusoidal mononuclear cells cultured in vitro were nonviable within 48 h after isolation, while only 10% of peripheral blood mononuclear cells died under the same conditions. Sinusoidal mononuclear cells showed DNA ladder formation of DNA on electrophoresis and characteristic morphological pattern on electron microscopic examination that suggested they had died in an apoptotic manner. The addition of human liver extracts or 2-mercaptoethanol and reduced glutathione to the cultures rescued the sinusoidal mononuclear cells from apoptosis. Furthermore, diamide, a sulfhydryl group specific oxidant, negated the effect of the liver extract. CONCLUSION: In comparison with peripheral blood mononuclear cells, human sinusoidal mononuclear cells were more subject to death by apoptosis ex vivo, which was reversed by exogenous agents producing reducing conditions. These results suggested that hepatic sinusoidal mononuclear cells might express a different sensitivity to redox environment than peripheral blood mononuclear cells.

Apoptosis↗
PubMed1997

Oxygen dependency of epidermal growth factor receptor binding and DNA synthesis of rat hepatocytes.

BACKGROUND/AIMS: Changes in oxygen availability modulate replicative responses in several cell types, but the effects on hepatocyte replication remain unclear. We have studied the effects of transient nonlethal hypoxia on epidermal growth factor receptor binding and epidermal growth factor-induced DNA synthesis of rat hepatocytes. METHODS: Lactate dehydrogenase activity in culture supernatant, intracellular adenosine triphosphate content, 125I-epidermal growth factor specific binding, epidermal growth factor receptor protein expression, and 3H-thymidine incorporation were compared between hepatocytes cultured in hypoxia and normoxia. RESULTS: Hypoxia up to 3 h caused no significant increase in lactate dehydrogenase activity in the culture supernatant, while intracellular adenosine triphosphate content decreased time-dependently and was restored to normoxic levels by reoxygenation (nonlethal hypoxia). Concomitantly, 125I-epidermal growth factor specific binding to hepatocytes decreased time-dependently (to 54.1% of normoxia) and was restored to control levels by reoxygenation, although 125I-insulin specific binding was not affected. The decrease in 125I-epidermal growth factor specific binding was explained by the decrease in the number of available epidermal growth factor receptors (21.37+/-3.08 to 12.16+/-1.42 fmol/10(5) cells), while the dissociation constant of the receptor was not affected. The change in the number of available receptors was not considered to be due to receptor degradation-resynthesis, since immunodetection of the epidermal growth factor receptor revealed that the receptor protein expression did not change during hypoxia and reoxygenation, and since neither actinomycin D nor cycloheximide affected the recovery of 125I-epidermal growth factor binding by reoxygenation. Inhibition of epidermal growth factor-induced DNA synthesis after hypoxia (to 75.4% of normoxia by 3 h hypoxia) paralleled the decrease in 125I-epidermal growth factor binding. CONCLUSIONS: Transient hypoxia, which caused no increase in lactate dehydrogenase leakage but affected intracellular adenosine triphosphate levels, did, however, modulate the number of available epidermal growth factor receptors without affecting the receptor protein expression, and inhibit the epidermal growth factor-induced DNA synthesis of hepatocytes. This suggests that even transient nonlethal hypoxia affects the epidermal growth factor-induced DNA synthesis of rat hepatocytes through reversible changes in the epidermal growth factor receptor molecule, which depends on oxygen availability.

Adenosine Triphosphate↗
PubMed1997

Control of centrifugal blood pump based on the motor current.

In this study, centrifugal pump performance was examined in a mock circulatory loop to derive an automatic pump rotational speed (rpm) control method. The pivot bearing supported sealless centrifugal pump was placed in the left ventricular apex to aorta bypass mode. The pneumatic pulsatile ventricle was used to simulate the natural ventricle. To simulate the suction effect in the ventricle, a collapsible rubber tube was placed in the inflow port of the centrifugal pump in series with the apex of the simulated ventricle. Experimentally, the centrifugal pump speed (rpm) was gradually increased to simulate the suction effect. The pump flow through the centrifugal pump measured by an electromagnetic flowmeter, the aortic pressure, and the motor current were continuously digitized at 100 Hz and stored in a personal computer. The analysis of the cross-spectral density between the pump flow and motor current waveforms revealed that 2 waveforms were highly correlated at the frequency range between 0 and 4 Hz, with the coherence and phase angles being close to 1.0 and 0 degree, respectively. The fast Fourier transform analysis of the motor current indicated that the second harmonic component of the motor current power density increased with the occurrence of the suction effect in the circuit. The ratio of the fundamental to the second harmonic component decreased less than 1.3 as the suction effect developed in the circuit. It is possible to detect and prevent the suction effect of the centrifugal blood pump in the natural ventricle through analysis of the motor current waveform.

Algorithms↗
PubMed1996

Long-duration xenogeneic extracorporeal pig liver perfusion with human blood.

Hepatic xenografts can tolerate hyperacute rejection owing to their lower susceptibility to humorally mediated injury. We investigated the possibility of long-duration xenoperfusion without immunologically controlling natural antibodies or complements. Pig livers were perfused for 9 h with human blood (Group 1) or pig blood (Group 2). Physiological conditioning and administration of prostaglandin E1 and insulin was characteristic of our system. The portal vein and hepatic artery pressure and bile production did not significantly differ between the two groups. Despite a gradual decrease throughout the perfusion, overall oxygen consumption was significantly higher in Group 1. Liver enzymes were released at higher levels in Group 1. Histological examination revealed intact hepatic architecture in Group 2, while in Group 1 interlobular morphology was severely damaged by endothelial disruption, although hepatic sinusoidal architecture was preserved. It is concluded that, despite biochemically and histologically confirmed tissue injury, graft viability was well-maintained in xenoperfusion even without immunological manipulations.

Alprostadil↗
PubMed1996

Guidelines for donor selection and an overview of the donor operation in living related liver transplantation.

Guidelines for donor selection and an overview of the donor operation are reported on the basis of our experience with 120 cases of living related liver transplantation (LRLT) in pediatric patients. Once the parents had clearly expressed their desire to serve as donors, tests were performed to functionally and anatomically screen the donor livers to determine whether or not the parents' general physical condition allowed them to serve as donors. We then evaluated which of the two parental candidates was more suitable as a donor. The wishes of the family as to which parent should serve as donor was considered secondary and taken into account only in a few cases in which certain functional and/or anatomical abnormalities were uncovered that made the prime candidate less suitable. For the 120 LRLTs, 135 candidates were evaluated as potential donors, 15 (11.1%) of whom were rejected for various reasons. The mean volume of blood loss during the donor operation decreased significantly from 489 g in the first 60 LRLTs to 390 g in the latter 60 LRLTs; this was accompanied by a significant decrease in the mean volume of autologous blood transfused from 449 g to 390 g. Mean cold ischemia time of the graft increased significantly from 71.4 to 128.0 min, while mean operation time conversely decreased from 6.7 to 6.2 h. Bile leakage from the cut surface of the remnant liver, which was the only post-operative surgical complication encountered, was noted in five cases. We conclude that donor candidates should be strictly selected according to basic guidelines, taking into account both the results of preoperative screening and the wishes of the family. With this accumuled experience, we have been able to simplify our LRLT operative procedure, resulting in decreases in blood loss volume, blood transfused, and operation time.

ABO Blood-Group System↗
PubMed1996

Evaluating the significance of HLA class II genotype matching in living-related liver transplantation.

To evaluate the clinical significance of HLA class II matching in living-related liver transplantation, the genotypes of HLA class II including DPB1 were determined by the PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) method and their matching was compared to the postoperative course. Conventional serotypes included 15.6% and 13.6% errors in DR and DQ, respectively. Among 42 consecutive cases that were followed up over 1 year after transplant, rejection occurred in seven cases. There was no correlation between the matching for each locus and the frequency of rejection episodes. In this study, rejection-free cases were investigated in terms of the potency of immunosuppressive therapy and graft function during 1 year after operation. The doses of tacrolimus in unmatched cases tended to be larger than those in matched cases for every locus except for DQA1. Its trough levels in matched cases were lower than those in unmatched cases, especially at 9-12 months after operation for DRB1 (p < 0.05). The termination of steroid administration tended to be postponed in unmatched cases for every locus. Serum levels of asparatan transaminase, alanine transaminase gamma-glutamyltranspeptidase (gamma-GTP) and total bilirubin were generally lower in matched cases than in unmatched ones for DRB1, DQB1 and DPB1, while in DQA1 the tendency was the opposite, especially total bilirubin and gamma-GTP, which were p < 0.02 and p < 0.05, respectively, at 6 months after operation. Investigation of subclinical immune responses other than rejection episodes showed that DRB1, DQB1 and DPB1 matching had a beneficial effect on graft function, while DQA1 matching seemed to have a varied effect.

Child↗
PubMed1996

Medication of feedlot calves infected with Eimeria spp. by a combination of sulfamonomethoxine and ormetoprim.

Feedlot calves naturally infected with Eimeria spp. were medicated by a combination of sulfamonomethoxine and ormetoprim (Ektecin). Calves, less than one year old and positive for coccidiosis, were administered with Ektecin (5, 10 and 20 ml/100 kg of body weight/day) and Daimeton (100% sulfamonomethoxine: 5 g/100 kg of body weight/day) for five days. No diarrhea were found on and after 3 days of medication in all the groups, and no oocysts were detected on and after day 5, 2, 1 or 3 from calves of the respective medicated groups. In samples from a group of calves administered with lowest dose of Ektecin, eimerian oocysts of 4 species were detected on day 0, and additionally 3 species (totally 7 species) were found on day 3 of medication.

Animals↗