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Biomedical subjects

Y Miyao

Publications and source records attributed to Y Miyao.

At least 91 records · Page 5Linked to original sources
PubMed1992

Retrovirus-mediated gene transfer targeted to malignant glioma cells in murine brain.

A murine model for meningeal metastasis of malignant glioma was developed to study selective gene transfer into tumor cells and to establish a reliable means of determining the rate of tumor cell infection. A murine ecotropic retroviral vector was created in which the Escherichia coli beta-galactosidase gene served as a marker for gene expression from the integrated retrovirus. This retrovirus exhibited a high rate of infectivity in RSV-M mouse glioma cells in vitro. The recombinant retrovirus was injected directly into the cisterna magna of the mice. Staining of beta-galactosidase showed that the rate of gene integration was high in the disseminated glioma cells. These results suggest the possibility of retrovirus-mediated gene therapy for meningeal dissemination of malignant glioma.

Animals↗
PubMed1991

A position-dependent silencer plays a major role in repressing alpha-fetoprotein expression in human hepatoma.

A large percentage of human hepatomas produce alpha-fetoprotein (AFP), but the levels of AFP expression vary greatly among hepatomas. To understand the molecular basis for this variation, we analyzed transcriptional regulatory activities associated with the 5'-flanking region of the AFP gene in two human hepatoma cell lines, HuH-7 and huH-1/cl-2, which produce a high and a low level of AFP, respectively. We found that the low level of AFP production in huH-1/cl-2 is due to the action of at least two silencer regions located between the enhancer and the promoter of the AFP gene. In contrast, no silencer activity is expressed in HuH-7. We identified 5'-CTTCATAACTAATACTT-3' to be a core sequence responsible for the negative regulatory activity. This sequence is repeated four times in a strong, distal silencer region, Sd, whereas one copy is present in a weak, proximal silencer region, Sp. The silencer reduces transcriptional initiation by blocking enhancer activation of the AFP promoter in a position-dependent manner. The silencer functions in the presence of positive transcription factors and may play a key role in developmental repression as well as variable expression of the AFP gene in hepatomas.

Albumins↗
PubMed1991

Murine model of leptomeningeal dissemination using human medulloblastoma cells.

An experimental model of meningeal dissemination was developed by intracisternal inoculation of human medulloblastoma (ONS-76) cells into nude mice. All mice died within 65 days after inoculation of 1 x 10(7) tumor cells. The median survival time was 56 days. Clinical signs and histological findings were similar to those in medulloblastoma patients with meningeal dissemination. Immunohistochemical studies showed that ONS-76 cells in the subarachnoid space expressed major histocompatibility complex (MHC) class I antigens until 20 days after inoculation. After 30 days, expression of MHC class I antigens decreased and cells began to proliferate rapidly. Expression of MHC class I antigens on tumor cells may result in effective recognition by the host immune system.

Animals↗
PubMed1990

c-Ha-ras down regulates the alpha-fetoprotein gene but not the albumin gene in human hepatoma cells.

We studied the effects of transfection of the normal c-Ha-ras gene, rasGly-12, and its oncogenic mutant, rasVal-12, on expression of the alpha-fetoprotein (AFP) and albumin genes in a human hepatoma cell line, HuH-7. The mutant and, to a lesser extent, the normal ras gene caused reduction of the AFP mRNA but not the albumin mRNA level in transfected HuH-7 cells. Cotransfection experiments with a rasVal-12 expression plasmid and a chloramphenicol acetyltransferase reporter gene fused to AFP regulatory sequences showed that rasVal-12 suppressed the activity of enhancer and promoter regions containing A + T-rich sequences (AT motif). In contrast, rasVal-12 did not affect the promoter activity of the albumin and human hepatitis B virus pre-S1 genes even though these promoters contain homologous A + T-rich elements. ras transfection appeared to induce phosphorylation of nuclear proteins that interact with the AFP AT motif, since gel mobility analysis revealed the formation of slow-moving complexes which was reversed by phosphatase treatment. However, similar changes in complex formation were observed with the albumin and hepatitis B surface antigen pre-S1 promoters. Therefore, this effect alone cannot explain the specific down regulation of the AFP promoter and enhancer activity. ras-mediated suppression of the AFP gene may reflect the process of developmental gene regulation in which AFP gene transcription is controlled by a G-protein-linked signal transduction cascade triggered by external growth stimuli.

Antibodies, Monoclonal↗
PubMed1989

Involvement of an AFP1-binding site in cell-specific transcription of the pre-S1 region of the human hepatitis B virus surface antigen gene.

Human hepatitis B virus infection is characterized by a high degree of hepatotropism which may be due to the dependency of viral genes on specific host factors for their expression. To learn more about such a requirement and the molecular basis of the viral tissue tropism we analyzed the promoter function in the pre-S1 region of the surface antigen gene. DNase I footprinting and competition gel retardation assays showed that a sequence with an AT-rich core (AT motif) in the pre-S1 promoter region interacts with AFP1, a hepatoma nuclear factor that binds to the alpha-fetoprotein enhancer and promoter. Functional analysis of the pre-S1 AT motif by transient transfection assays showed that this element is important in cell-specific transcriptional initiation. These results suggest that AFP1 may be one of the factors determining the liver specificity of human hepatitis B virus.

Base Sequence↗
PubMed1989

[Cardiovascular effects of beraprost sodium (TRK-100), a prostacyclin analogue in the dog].

Effect of prostacyclin analogue, beraprost sodium (Sodium (+/-)-(1R*, 2R*, 3aS*, 8bS*)-2, 3,3a,8b-tetrahydro-2-hydroxy-1-[(E)-(3S*)-3-hydroxy-4-methyl-1-octen+ ++-6- ynyl]-1H-cyclopenta-[b]benzofuran-5-butyrate, TRK-100), on the cardiovascular system of the anesthetized dog was investigated. TRK-100 was injected intra-arterially and intravenously to study the vasodilating effect of the drug by a magnetic flow meter. Intra-arterial injection of TRK-100 augmented blood flow of vertebral, coronary, renal, supramesenteric, hepatic and femoral artery at a dose range of 0.0003 to 3,000 micrograms/bed. The threshold doses of TRK-100 and PGI2 in the mesenteric artery were 0.003 micrograms and 0.0003 micrograms, respectively, and the same values were obtained in the splenic artery. Those were slightly lower than those of other arteries. Intravenous injection of TRK-100 augmented mesenteric and renal arterial flow to 193 +/- 30% and 118 +/- 4%, respectively. In this system augmentation of mesenteric and renal arterial flow was 179 +/- 19% and 135 +/- 1%, respectively, while vertebral, carotid, and femoral arterial flow decreased, respectively, to 71.4 +/- 2.1%, 80.0 +/- 9.4% and 61.4 +/- 5.6% by TRK-100 and 70.6 +/- 5.6%, 79.5 +/- 6.9% and 67.1 +/- 4.7% by PGI2. Inhibitory effects on heart functions such as cardiac output, left ventricular pressure, LV dP/dt, oxygen consumption, and cardiac work were seen. The effect was similar to PGI2. Coronary vascular resistance, total peripheral resistance and systemic blood pressure were also decreased by TRK-100 and PGI2.

Anesthesia↗
PubMed1989

[Adoptive immunotherapy in patients with medulloblastoma by LAK cells].

Medulloblastoma is one of the most popular malignant brain tumors in children. It accounts for about 15% of all pediatric brain tumors. Radiochemotherapy has prolonged the 5-year survival rate up to 60-85% for patients with medulloblastoma. But the conventional therapy is not so effective to recurrent cases, especially with meningeal dissemination, and generally fatal. There remains a big problem of the neurotoxicity to infants in a growth process under the whole-neuraxis irradiation and chemotherapy. Aiming to relieve the radiation and antitumor drugs, adoptive immunotherapy is greatly expectant. We have had clinical trials of adoptive immunotherapy for 8 patients with medulloblastoma by lymphokine-activated killer (LAK) cells. They were from 2-9 years in age and had cerebrospinal fluid (CSF) dissemination of the tumors. All patients underwent the whole-neuraxis irradiation and chemotherapy. After they had CSF dissemination, they were submitted to an adoptive transfer of allogeneic LAK cells. LAK cells were induced from peripheral blood lymphocytes (PBL) of their relatives with human recombinant interleukin-2. 3-15 x 10(9) LAK cells were transferred intrathecally in 2-3 months. In 3 of 8 patients, neurological signs were improved and malignant cells had never been detected on CSF cytology after the adoptive immunotherapy. One among these 3 patients showed complete response in 20 months. Thus, this is an attractive treatment for patients with medulloblastoma, especially with CSF dissemination, which cannot be cured by current therapeutic intervention.

Brain Neoplasms↗
PubMed1988

Transplant-induced recovery from 6-OHDA lesions of the nigrostriatal dopamineneurones in mice.

Attempts to reconstruct the damaged nigrostriatal pathway in experimental models of Parkinson's disease have thus far been carried out in animals with neurotoxically induced dopamine deficiency. Our study established that unilateral 6-hydroxydopamine (6-OHDA) lesions of the nigrostriatal dopamine (DA) neurons produced a well-characterized functional asymmetry in the behaviour of the C57BL/6 (H-2b) mice. The intraperitoneal administration of methamphetamine induced ipsilateral rotation at 7-20 turns/min 1 x 10(6) syngenic DA-rich cells of embryonic ventral mesencephalon were stereotaxically transplanted in the caudate-putamen. A complete recovery of methamphetamine-induced rotational response was produced around the 60th day after the syngenic cell suspension graft. And a complete compensation of the rotational response was also brought about with the DA-rich cells from embryonic ventral mesencephalon (crown-rump length; 10-13 mm) of allogenic C3H/HeN (H-2k) mice. The FACS IV analysis revealed no H-2 (Kk and Iak) antigens before transplantation of these embryonic cells. Immunohistochemistry showed that the dopaminergic fibers had grown predominantly into the ipsilateral caudate-putamen. These results provide evidence of integration of syngenic and allogenic grafts and host tissue. And the immunological response in the transplanted brain are under investigation.

Animals↗
PubMed1988

Effects of phenytoin on cell-mediated immunity.

The effects of phenytoin on cellular immunity were examined in murine models. Fresh splenocytes were obtained from mice which had received 1 mg/day of phenytoin i.p. for 28 days. The serum concentration of phenytoin in these animals was 10-20 micrograms/ml. The proliferative response of splenocytes to mitogens was assessed by 3H-thymidine incorporation. The cytotoxic activities of cells such as natural killer (NK) cells, cytotoxic T lymphocytes (CTL), and lymphokine-activated killer (LAK) cells were estimated by a 4-h 51Cr release assay. The 3H-thymidine incorporation of splenocytes was reduced significantly (P less than 0.01) in phenytoin-treated mice. The NK and CTL activities of splenocytes from phenytoin-treated mice were significantly suppressed. However, the LAK activity of phenytoin-treated mice was equal to that of control mice.

Animals↗
PubMed1988

An adoptive immunotherapy of patients with medulloblastoma by lymphokine-activated killer cells (LAK).

An adoptive immunotherapy of 6 patients with medulloblastoma by lymphokine-activated killer (LAK) cells is described. They were from 2 to 9 years in age and had cerebrospinal fluid (CSF) dissemination of the tumours. All patients underwent the whole-neuraxis irradiation and chemotherapy. After the usual treatments, they were submitted to an adoptive transfer of one-haplotype identical LAK cells. The LAK cells were induced from peripheral blood lymphocytes (PBL) of their relatives with human recombinant interleukin-2 (rIL-2). 3 - 15 x 10(9) LAK cells were transferred intrathecally in 2-3 months. In 3 of 6 patients, neurological signs were improved and malignant cells had never been detected on CSF cytology after the adoptive immunotherapy. One among these 3 patients showed complete response in 20 months. Thus, this is an attractive approach for the treatment of medulloblastoma with CSF dissemination of the tumour which current therapeutic intervention can not cure.

Cerebellar Neoplasms↗
PubMed1988

[Transplant-induced recovery from 6-OHDA lesions of the nigro-striatal dopamine neurons in mice].

Attempts to reconstruct the damaged nigrostriatal pathway in experimental models of Parkinson disease have thus far been carried out in animals with neurotoxically induced dopamine deficiency. Our study established that unilateral 6-hydroxydopamine (6-OHDA) lesions of the nigrostriatal-dopamine (DA) neurons produced a well-characterized functional asymmetry in the behavior of C57BL/6 (H-2b) mice. The intraperitoneal administration of methamphetamine induced ipsilateral rotation at 7-20 turns/min. 11 x 10(6) syngenic DA-rich cells of embryonic ventral mesencephalon were stereotaxically transplanted in the caudate-putamen. A complete recovery of methamphetamine-induced rotational response was produced around the 60-th day after the syngenic cell suspension graft. And a complete compensation of the rotational response was also brought about with the DA-rich cells from embryonic ventral mesencephalon (crown-rump length; 10-13 mm) of allogenic C 3 H/HeN (H-2k) mice. The FACS IV analysis revealed no H-2 (Kk and Iak) antigens before transplantation of these embryonic cells. Immunohistochemistry showed that the dopaminergic fibers had grown predominantly into the ipsilateral caudate-putamen. These results provide evidence of integration of syngenic and allogenic grafts and host tissue. And the immunological response in the transplanted brain are under investigation.

Animals↗
PubMed1988

Pharmacological effects of urapidil on bronchospasm, myocardial hypoxia and postural hypotension in experimental animals.

We studied the effects of urapidil on bronchospasm, myocardial hypoxia and postural hypotension in experimental animals. Urapidil dose-dependently inhibited bronchospasm induced by histamine in anaesthetized guinea pigs and the contraction of isolated trachea induced by noradrenaline or phenylephrine. Urapidil markedly delayed the appearance of severe dyspnoea induced by histamine aerosol in guinea pigs. Further, urapidil inhibited isoproterenol-induced ST depression in rats and inhibited histamine-induced ST depression in rabbits. The postural hypotension induced by prazosin was greater than that induced by urapidil in equihypotensive doses in conscious rabbits. Urapidil induced a lesser alpha-blockade in the vein than in the artery compared with prazosin. These combined properties of urapidil suggest that the drug is worth investigation in hypertensive patients with bronchial asthma or ischaemic heart disease.

Animals↗
PubMed1987

Adoptive immunotherapy of human meningeal gliomatosis and carcinomatosis with LAK cells and recombinant interleukin-2.

Previous in vitro studies have demonstrated that peripheral blood lymphocytes activated with recombinant interleukin-2 (rIL-2) generated cells that were lytic for fresh autologous tumor cells but not for normal lymphocytes or lymphoblasts. Adoptive transfer of autologous lymphokine-activated killer (LAK) cells induced in vitro with rIL-2 was used in two patients: one with meningeal gliomatosis and the other with meningeal carcinomatosis. The adoptive transfer of LAK cells was very effective in reducing the clinical symptoms and signs, and in eliminating the malignant cells from the cerebrospinal fluid. Thus, this therapy is an attractive approach for the treatment of malignant tumors that have poor immunogenicity and are insensitive to several anti-cancer agents, and for patients with severe immunosuppressive conditions induced by repeated radiation therapy or chemotherapy.

Adult↗
PubMed1987

[Experimental studies on the treatment of recurrent gliomas].

For the purpose to study reasonable treatment for recurrent gliomas, in vitro immunochemosensitivity tests were performed by using human malignant glioma cell line (ONS-12) and its ACNU-resistant cell line (ONS-12/ACNU), which were established in our laboratory. ONS-12/ACNU cells showed a cross-resistance to Ara-C, but not for cisplatin and methotrexate. The lymphokine-activated killer (LAK) cells induced in vitro from the peripheral blood lymphocytes (PBL) of healthy subjects, showed stronger cytotoxicity to ONS-12/ACNU than ONS-12 cells. From these data, selection of appropriate anti-tumor agents on the in vitro sensitivity tests was a most useful method for the treatment of recurrent gliomas, and the adoptive immunotherapy with LAK cells may be useful for ACNU-resistant gliomas.

Antineoplastic Agents↗
PubMed1987

[Effects of phenytoin on cell-mediated immunity].

Phenytoin is a highly effective anticonvulsant agent that is widely administrated to prevent some kinds of patients with brain tumor. But it has been said that phenytoin may have some immunosuppresive potential for hosts. In this study, we evaluated the effects of phenytoin upon cellular immunity such as NK, CTL and LAK activity in murine models. Fresh splenocytes were taken out from mice (CBA/J, C 3 H/HeN, C 57 BL/6) into which phenytoin had been injected intraperitoneally at a daily dose of 1,000 micrograms for 28 days. The serum concentration of phenytoin in the experimental models was 10-20 micrograms/ml. The cytotoxic activities were estimated by a 4-hr 51Cr release assay. The mitogen-stimulated lymphocyte function was evaluated by 3H-thymidine incorporation into DNA. The NK activity was estimated by cytotoxicity of splenocytes of CBA/J mice against NK-sensitive YAC-1 cells. The cytotoxic T-lymphocyte (CTL) activity was estimated by cytotoxicity of splenocytes of C 57 BL/6 mice which were stimulated in vitro for 5 days by splenocytes of C 3H/HeN treated with mitomycin C, against RSV-M glioma cells. Lymphokine-activated killer (LAK) activity was estimated by cytotoxicity of LAK cells, which were induced from splenocytes of C 3 H/HeN mice by human recombinant interleukin-2 (rIL-2), against syngeneic RSV glioma and allogeneic 203 glioma cells. 3H-thymidine incorporation of splenocytes of C 57 BL/6 mice was reduced significantly (p less than 0.01) in phenytoin-treated mice. The cytotoxicity of splenocytes of non-treated CBA/J mice against YAC-1 cells was 75%, but that of phenytoin-treated CBL/J mice was a few %.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

[Antitumor efficacy of recombinant interferon-beta on human glioma].

The antitumor efficacy of recombinant interferon-beta (rIFN-beta) on human glioblastomas was investigated in vitro and in meningeal gliomatosis(MG) models. A total of 1.5 X 10(5) human glioma (ONS-12 and ONS-20) cells were suspended in 2 ml of RPMI-1640 with 10% fetal calf serum and placed in plastic dishes (Falcon #3001). rIFN-beta 10(2)-10(5) units were then added to each culture dish on days 3, 5 and 7. Both ONS-12 and ONS-20 human glioma cells were suppressed with a low dose of rIFN-beta. As MG models, 5 X 10(7) ONS-12 glioma cells were suspended in saline and transcutaneously inoculated into the cisterna magna of BALB/c nu/nu mice using a 27-gauge needle. The median survival times (MST) of MG models which were treated by intrathecal administration of 10(3) U of rIFN-beta and intraperitoneal injection of 10(4) U of rIFN-beta were 11.0 and 8.0 days, compared with an MST of 7 days for control mice. The rIFN-beta was not effective by intraperitoneal administration but was effective by intrathecal administration in the MG models. The MSTs of MG models which were treated by administration of 10(5) U, 10(3) U of rIFN-beta and 0.1 ml saline were 15.0, 19.0 and 9.0 days, respectively. The therapeutic efficacy in MG models depended on the administration route of rIFN-beta, and as far as could be determined from the MG models, high-dose administration of rIFN-beta was not always useful.

Animals↗