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T Asano

Publications and source records attributed to T Asano.

1,003 records · Page 56Linked to original sources
PubMedDate not supplied

A proposal of no-touch isolation technique in pancreatoduodenectomy for periampullary carcinomas.

BACKGROUND/AIMS: The procedure of pancreatoduodenectomy for periampullary cancers accompanies a risk to shed cancer cells into a portal vein while handling the pancreas head lesion. This manipulation may subsequently cause a liver metastasis. We devised the no-touch isolation technique for pancreatoduodenectomy without removing a portal vein, for the purpose of preventing the manipulated shedding of cancer cells into a portal vein and liver metastasis. METHODOLOGY: The fundamental procedure of this technique is that isolation of portal vein precedes the handling of tumor mass. Isolation of a portal vein is carried out with the ligature of its surrounding veins after dividing of duodenum and pancreas. We applied the no-touch isolation technique for 10 cases, which consisted of 6 cases of distal bile duct carcinoma and 4 cases of ampullary carcinoma, between May 1993 and July 2000. RESULTS: There was neither operative mortality nor liver metastasis cases in these cases. CONCLUSIONS: The no-touch isolation technique without removing a portal vein might be recommended as a safe and reasonable procedure for periampullary cancer patients who have the potential for subsequent liver metastasis.

Bile Duct Neoplasms↗
PubMedDate not supplied

Electroporation-mediated transfer of cytokine genes into human esophageal tumors produces anti-tumor effects in mice.

Electroporation facilitates transfer of chemicals or plasmid DNA from extracellular milieu into cells by increasing the permeability of the cell membrane. Delivery of electric pulses to established tumors thereby can improve the susceptibility of tumors to an anti-cancer agent administered. We examined whether electroporation-mediated transfer of cytokine genes into solid tumors could produce anti-tumor effects in the tumor-bearing mice. Plasmid DNA containing cytokine genes were injected into human esophageal T.Tn tumors developed in nude mice and electric pulses were then delivered. Administration of murine GM-CSF or human IL-2 gene followed by electroporation significantly suppressed the subsequent growth of T.Tn tumors and prolonged the survival of the inoculated mice. In contrast, electroporation-mediated introduction of a control gene, human GM-CSF gene, whose products do not bind to murine GM-CSF receptors, did not achieve any anti-tumor effects. In vivo transfection of cytokine genes with electroporation could be a possible therapeutic strategy for established solid tumors.

Animals↗
PubMedDate not supplied

Arterio-portal shunt in liver rescued by hepatectomy after arterial embolization.

Arterio-portal shunts are generally treated with transcatheter arterial embolization, as a therapeutic measure for bleeding of esophageal varices. However, transcatheter arterial embolization is frequently associated with reestablishment of arterio-portal shunts. We now report our experience with partial hepatectomy to remove the arterio-portal shunt associated with esophageal varices, which recurred after transcatheter arterial embolization. The patient was a 60-year-old female, who had massive hematemesis caused by rupture of esophageal varices. Doppler sonography and arteriography demonstrated an arterio-portal shunt in the right anterior superior segment of the liver. Temporary hemostasis was achieved with transcatheter arterial embolization, however, hemorrhage recurred one month later. The second transcatheter arterial embolization failed to manage the shunt and varices. The patient developed hepatic coma. After recovery from coma, she was referred to our hospital. We carried out partial hepatectomy, which provided remarkable hemodynamic improvement; the portal vein flow changed from hepatofugal to hepatopetal. Esophageal varices and hepatic coma have totally disappeared. This patient has had no complaint and has remained free of esophageal varices, for 3 years postoperatively. She is having a normal life. The partial hepatectomy to remove the arterio-portal shunt induced complete resolution of the arterio-portal shunt, as well as dramatic improvement in portal flow and hepatic coma. Our experience in the present case suggests that partial hepatectomy should be considered as a radical therapy for arterio-portal shunt, without insistence on transcatheter arterial embolization.

Arteriovenous Fistula↗
PubMedDate not supplied

Quantitation of cerebral blood volume by 99mTc-DTPA-HSA SPECT.

The characteristics of technetium-99m diethylenetriaminepentaacetic acid human serum albumin (99mTc-DTPA-HSA) as an agent for quantitation of cerebral blood volume (CBV) were examined. The radioactivity after decay correction as a percentage of the activity at 10 minutes was 84.3 +/- 1.3% at 120 minutes after the injection of 99mTc-DTPA-HSA. Radioactivity was found exclusively in plasma, with little in blood cells. The blood retention of 99mTc-DTPA-HSA is sufficient, and its use in the quantitation of CBV omits the need for centrifugation of the blood sample. CBV quantified using the tracer and a SPECT system with a single-head rotating gamma camera was 4.09 +/- 0.60 ml/100 g brain, similar to values reported previously. Two serial SPECT scans provided similar images, and the CBV values determined by the two scans were closely correlated (p < 0.001). The high reproducibility suggests that the method may be used to monitor the cerebrovascular response to drugs. It was concluded that 99mTc-DTPA-HSA has useful properties for quantitative CBV measurement and that quantitation of CBV by 99mTc-DTPA-HSA SPECT is feasible using a system with a single-head rotating gamma camera.

Adult↗
PubMedDate not supplied

ABCB1 C3435T polymorphism influences methotrexate sensitivity in rheumatoid arthritis patients.

OBJECTIVE: Methotrexate (MTX) is most widely used for the treatment of rheumatoid arthritis (RA). However, it has certain drawbacks with regard to individual differences in its therapeutic effects as well as the differences in the patients' response to MTX therapy. We investigated whether multi-drug resistance-1 (ABCB1) C3435T, reduced folate carrier-1 (RFC1) G80A, 5-aminoimidazole-4-carboxamide ribonucleotide transformylase (ATIC) C347G and a 6bp-deletion polymorphism in the 3'-untranslated region of the thymidylase synthase (TYMS) gene are predictive of MTX sensitivity and its adverse effects. METHODS: Patients whose last maintenance dosage of MTX was 6 mg/week or those in whom MTX therapy was changed due to poor response to MTX were regarded as non-responders. The data of 124 RA patients who had received MTX treatment were retrospectively analyzed for polymorphisms in the ABCB1, RFC1, ATIC and TYMS genes, MTX sensitivity and MTX toxicity. RESULTS: There were no significant differences in MTX sensitivity among the genotypes of RFC1, ATIC and TYMS genes. ABCB1 3435TT cases included statistically significantly more non-responders than 3435CC cases according to univariate analysis (crude odds ratio (OR) = 8.91, p = 0.001) and multivariate analysis (adjusted OR = 8.78, p = 0.038). There were no significant differences in MTX toxicity among the genotypes of all the genes. CONCLUSION: These results suggested that the genetic diagnosis of ABCB1 C3435T can be applied to determine MTX sensitivity for the treatment of RA patients. However, further pharmacokinetics studies are required in this regard.

ATP Binding Cassette Transporter, Subfamily B↗
PubMedDate not supplied

Study of irradiation effects on cytokine secretion from retrovirally-transduced tumor cells: a model for tumor vaccination.

We have examined the effects of irradiation on the cytokine secretion from genetically modified human esophageal and gastric carcinomas. Both cell lines were transduced retrovirally to secrete interleukin-2, interleukin-6 and granulocyte-macrophage colony-stimulating factor, respectively. The metabolism of all the transduced cells was partially inhibited by 6 Gy, and greatly inhibited by 20 Gy irradiation. Cytokine productions, however, was not affected by 6 Gy in many cases, and continued to be detected even after 60 Gy irradiation. The analysis of the dose and time of irradiation in each cytokine producer is useful for the designing of tumor vaccine using cytokine gene transfer.

Cell Division↗
PubMedDate not supplied

Discordant production of released exogenous protein and infectious virions from retrovirus-packaging cells used for gene transduction.

We examined the correlation between the amount of exogenous protein secreted and that of its viral transcript from PA317 packaging cells transduced with a cytokine gene. Amphotropic packaging cells for the retrovirus expressing murine interleukin-15 (IL-15) gene were cloned, and we examined 22 clones for both the amount of IL-15 secreted with enzyme-linked immunosorbent assay and the IL-15 transcript released as infectious virions by slot blot-hybridization analysis. The study revealed that there was no statistical correlation between them, and suggests that the integrated transcript is used discordantly. Thus, the examination of secreted protein from packaging cells cannot be substituted for laborious assays to determine the amount of virion transcripts when isolating high titer packaging cells.

Animals↗
PubMedDate not supplied

Inhibition of experimental lung metastasis of murine colon carcinoma cells depends on the amount of interleukin-2 secreted from the transduced cells.

We examined the antitumor effect of low and high interleukin-2 (IL-2) producers of murine colon carcinoma cells (Colon 26) which were generated by transduction with IL-2 gene in an experimental lung metastasis model using syngeneic mice. Intravenous injection of the low IL-2 producer cells formed multiple lung metastatic foci and the survival of the mice was not different from that of the mice injected with wild-type cells. However, the mice administrated with the high producer cells survived significantly longer. Subcutaneous inoculation of the low producers, although it caused the development of local tumors at the inoculation sites in some of the mice tested, inhibited lung metastasis of wild-type cells subsequently inoculated and prolonged the survival of the mice rechallenged with Meth A cells, syngeneic fibrosarcoma cells. In contrast, inoculation of the high producers did not cause the development of subcutaneous tumors and inhibited the experimental metastasis of parental but not Meth A cells inoculated thereafter. Thus, the amount of secreted IL-2 from tumor cells differentially influences antitumor effects by inducing tumor specific and nonspecific immunity.

Animals↗
PubMedDate not supplied

Induction of T cell dependent acquired immunity in syngeneic mice by the combined expression of interleukin-4 and granulocyte macrophage-colony stimulating factor gene in murine colon carcinoma cells.

The inoculation of cytokine-producing tumor cells into syngeneic animals can produce antitumor effects. We previously reported that injection of a mixed population of murine colon carcinoma (Colon 26) cells transduced with interleukin-4 (IL-4) gene with granulocyte macrophage-colony stimulating factor (GM-CSF) gene developed subcutaneous tumors in syngeneic mice, but these tumors thereafter regressed spontaneously (Oncology 1997;54:69-73). In this study, we found the generation of tumor-specific acquired immunity in the mice which had rejected the tumors of a mixed population of IL-4 and GM-CSF producer cells, and that the immunity was mediated by mature T cells. Moreover, local secretion of both IL-4 and GM-CSF in the vicinity of tumors was found to be crucial for this rejection. These data suggest that enhanced host defense brought about by the combined expression of IL-4 and GM-CSF genes in tumor cells is a potential therapeutic strategy.

Animals↗
PubMedDate not supplied

Inhibition of peritoneal dissemination of murine colon carcinoma cells by administrating retrovirus harboring IL-2 gene.

We have examined the antitumor effect of the retrovirally expressed interleukin-2 (IL-2) gene in murine colon carcinoma cells (Colon 26) on a disseminated model within the peritoneal cavity. Intraperitoneal injection of IL-2-producing Colon 26, but not wild-type cells, into syngeneic mice did not cause animal death and conferred T-cell-dependent, tumor-specific protective immunity on the inoculated mice. Direct administration of the retrovirus harboring IL-2 gene into the peritoneal cavity of the mice that had intraperitoneal tumor of wild-type cells significantly prolonged the survival of the mice compared with that of the mice that received control retrovirus. In the surviving mice treated with the retrovirus we also observed the induction of protective immunity with tumor specificity. Integrated retrovirus DNA was not detected in any organs examined. Thus, in vivo IL-2 gene transfer by retrovirus enabled tumor-bearing mice to generate antitumor immunity without unnecessary retroviral insertion into host genome.

Adenocarcinoma↗