PubMed Health⌕ Search

Biomedical subjects

Y Teramura

Publications and source records attributed to Y Teramura.

At least 19 recordsLinked to original sources
PubMed2001

Fibrinogen-conjugated albumin polymers and their interaction with platelets under flow conditions.

Albumin polymers, having an average diameter of 1020 +/- 250 nm, were prepared by the disulfide polymerization of recombinant human serum albumin (rHSA) by controlling of the pH and temperature. Fibrinogen could be conjugated on the surface of an albumin polymer using N-succinimidyl 3-(2-pyridyldithio)propionate (SPDP). Under flow conditions, the fibrinogen-conjugated albumin polymers (fibrinogen-albumin polymers) were irreversibly attached to the platelet-immobilized surface in the reconstituted blood at a low platelet concentration ([platelet] = 5.0 x 10(4)/microL, a 5-fold diluted platelet concentration), and the attachment was suppressed by the addition of anti-GPIIb/IIIa monoclonal antibodies. It was confirmed that fibrinogen-albumin polymers specifically interacted with GPIIb/IIIa expressed on the surface of the activated platelets. Although platelets with a low platelet concentration were hardly attached to the platelet-immobilized surface under the flow conditions, the addition of fibrinogen-albumin polymers enhanced the attachment of the remaining platelets to the surface, indicating that the fibrinogen-albumin polymers would help the hemostatic ability of platelets at the site of vascular injury of patients in thrombocytopenia.

Biocompatible Materials↗
PubMed2000

Conjugation of von Willebrand factor-binding domain of platelet glycoprotein Ib alpha to size-controlled albumin microspheres.

Albumin microspheres (AMS), of which the average diameter is 240 +/- 10 nm, were prepared by pH control and heat treatment. Cytochrome c and rGPIb alpha; a water-soluble fragment of the alpha chain of a recombinant platelet glycoprotein (GP)Ib containing a von Willebrand factor (vWf)-binding site were selected as a receptor protein. Cytochrome c was used as a probe protein for monitoring. Onto the surface of the AMS and those proteins, N-succinimidyl 3-(2-pyridyldithio)propionate (SPDP) was reacted through the amide linkage to obtain PD-AMS, PD-cytochrome c, and PD-rGPIb alpha, respectively. The latter two were further reduced to SH-cytochrome c and SH-rGPIb alpha by dithiothreitol and conjugated with PD-AMS by a thiol-disulfide exchange reaction. The resulting AMS contain cytochrome c or rGPIb alpha of about 25,000 or 2500 molecules, respectively. The addition of ristocetin to the rGPIb alpha-AMS in the presence of vWf caused specific aggregation. Furthermore, the rGPIb alpha-AMS enhanced the ristocetin induced platelet aggregation in a low platelet concentration (4.0 x 10(7)/mL).

Blood Platelets↗
PubMed1999

The disposition of 14C-labeled tacrolimus after intravenous and oral administration in healthy human subjects.

Tacrolimus is a macrolide lactone with potent immunosuppressive properties. It has been shown in clinical studies to prevent allograft rejection. The pharmacokinetics of tacrolimus in healthy subjects and transplant patients has been described in earlier studies using immunoassay methods; however, detailed information on the absorption, distribution, metabolism, and excretion of tacrolimus using a radiolabeled drug is lacking. The objective of the present study was to characterize the disposition of tacrolimus after single i.v. (0.01 mg/kg) and oral (0.05 mg/kg) administration of 14C-labeled drug in six healthy subjects. Tacrolimus was absorbed rapidly after oral dosing with a mean Cmax and Tmax of 42 ng/ml and 1 h, respectively. The oral bioavailability was about 20%. After i.v. and oral dosing, most of the administered dose was recovered in feces, suggesting that bile is the principal route of elimination. Urinary excretion accounted for less than 3% of total administered dose. In systemic circulation, unchanged parent compound accounted for nearly all the radioactivity; however, less than 0.5% of unchanged drug was detectable in feces and urine. The excretion of the metabolites was formation-rate-limited. The mean total body clearance at 37.5 ml/min was equivalent to about 3% of the liver blood flow. Renal clearance was less than 1% of the total body clearance. The mean elimination half-life was 44 h.

Administration, Oral↗
PubMed1997

Neuroprotective actions of FK506 in experimental stroke: in vivo evidence against an antiexcitotoxic mechanism.

The cellular mechanisms underlying the neuroprotective action of the immunosuppressant FK506 in experimental stroke remain uncertain, although in vitro studies have implicated an antiexcitotoxic action involving nitric oxide and calcineurin. The present in vivo study demonstrates that intraperitoneal pretreatment with 1 and 10 mg/kg FK506, doses that reduced the volume of ischemic cortical damage by 56-58%, did not decrease excitotoxic damage induced by quinolinate, NMDA, and AMPA. Similarly, intravenous FK506 did not reduce the volume of striatal quinolinate lesions at a dose (1 mg/kg) that decreased ischemic cortical damage by 63%. The temporal window for FK506 neuroprotection was defined in studies demonstrating efficacy using intravenous administration at 120 min, but not 180 min, after middle cerebral artery occlusion. The noncompetitive NMDA receptor antagonist MK801 reduced both ischemic and excitotoxic damage. Histopathological data concerning striatal quinolinate lesions were replicated in neurochemical experiments. MK801, but not FK506, attenuated the loss of glutamate decarboxylase and choline acetyltransferase activity induced by intrastriatal injection of quinolinate. The contrasting efficacy of FK506 in ischemic and excitotoxic lesion models cannot be explained by drug pharmacokinetics, because brain FK506 content rose rapidly using both treatment protocols and was sustained at a neuroprotective level for 3 d. Although these data indicate that an antiexcitotoxic mechanism is unlikely to mediate the neuroprotective action of FK506 in focal cerebral ischemia, the finding that intravenous cyclosporin A (20 mg/kg) reduced ischemic cortical damage is consistent with the proposed role of calcineurin.

Animals↗
PubMed1997

The effectiveness of active specific immunotherapy using interferon-gamma-gene-transduced tumor cells in a murine tumor model.

Active specific immunotherapy was examined in BALB/c mice using sonicated tumor extract(SE) from plasmacytoma MOPC104E or interferon-gamma-(IFN-gamma)-gene-transduced MOPC104E (Mu gamma), employing interleukin-1 (IL-1) as an adjuvant. Subcutaneous (s.c.) MOPC104E tumor growth was significantly suppressed in mice given a single preimmunization of IL-1 plus Mu gamma-SE, 9 days prior to inoculation, whereas the tumor growth in mice similarly pretreated with IL-1 alone or IL-1 plus MOPC104E-SE(MOPC-SE) was not affected; the mean tumor diameters on day 21 being 6.8 mm, 15.3 mm, and 13.2 mm, respectively. Two-dose preimmunization with Mu gamma-SE alone or IL-1 alone given 10 and 7 days prior to s.c. inoculation also resulted in profound suppression of tumor growth compared to the control. As postsurgical immunization, MOPC104E cells were injected into the foot pads of mice, followed by amputation of the tumor-bearing foot 20 days later, then treatment with IL-1 plus MOPC-SE or IL-1 plus Mu gamma-SE on days 4, 7, and 10 after the amputation. The mean survival of the mice treated with IL-1 plus Mu gamma-SE was significantly prolonged compared to that of the mice treated with IL-1 plus MOPC-SE, at 90.3 days vs 40.9 days, respectively (P < 0.05 by the Cox-Mantel test). These results suggest that SE prepared from IFN-gamma-gene-transduced MOPC104E is more effective for active specific immunotherapy than SE prepared from MOPC104E.

Animals↗
PubMed1996

Establishment and evaluation of a new chemiluminescent enzyme immunoassay for carcinoembryonic antigen adapted to the fully automated ACCESS system.

We have established a new chemiluminescent enzyme immunoassay for carcinoembryonic antigen (CEA), designated ACCESS CEA, which is adapted to the fully automated ACCESS immunoassay analyzer. The assay is based on a one step sandwich-type method using two monoclonal antibodies, one of which is immobilized on micrometer-size paramagnetic particles and the other is conjugated to alkaline phosphatase. Ten microliters of calibrators or sera are incubated for 5 minutes at 37 degrees C with the particles and with the alkaline phosphatase conjugate. The particles are then magnetically separated and washed to remove unbound components. Time needed to obtain the first result is less than 15 minutes. The assay range was 0.04-1000 micrograms/l of CEA, and the possible high-dose hook effect was prevented at CEA concentrations up to 100000 micrograms/l in this working range. The coefficient of variation (CV) for intra-assay precision was 3.0 to 4.7%, and inter-assay CV was 3.4 to 5.6%. The sample carryover was less than 0.001%. The analytical recovery ranged from 98 to 104% and a dilution linearity was demonstrated. No interference was detected in any sample with levels up to 300 mg/l for bilirubin, 12000 mg/l for haemoglobin, 50000 mg/l for human serum albumin, 8500 mg/l for triacylglycerol, and 500000 IU/l for rheumatoid factor. The ACCESS CEA assay also showed very homogeneous reactivity with purified CEA preparations from different tumours and could discriminate CEA from four CEA-related normal antigens tested. Serum samples (n = 362) from patients with malignant or non-malignant disease, as well as from healthy individuals, were analyzed by the ACCESS CEA assay and by the established IMx CEA assay. The CEA values determined by the ACCESS CEA assay were in good agreement with those determined by the IMx CEA assay, and the ACCESS CEA assay significantly increased the sensitivity and specificity of tumour diagnosis as compared with the IMx CEA assay.

Carcinoembryonic Antigen↗
PubMed1996

Binding of tacrolimus (FK506) with human plasma proteins re-evaluation and effect of mycophenolic acid.

Protein binding of tacrolimus (FK506) in human plasma was re-evaluated by equilibration dialysis and compared with that of FK506 previously reported by two different methods (about 99 and 77% by an ultrafiltration and ultracentrifugation method, respectively). The binding determined in this study was about 99% irrespective of FK506 concentrations added (0.5-10 ng/ml) and this value was very close to that estimated by the ultrafiltration method. The effect of mycophenolic acid (MPA, an active form of the immunosuppressant mycophenolate mofetil) and its glucuronide (MPAG, a major metabolite of mycophenolate mofetil in human plasma) on the binding was studied at concentration levels of 1 and 10 ng/ml of FK506. The binding was not affected significantly by the addition of MPA (25-100 micrograms/ml) and/or MPAG (100-1500 micrograms/ml). FK506 has already been reported not to cause significant changes of plasma protein binding of MPA. The results indicate that the unbound fraction of FK506 is about 1% in human plasma and that concomitant administration of FK506 and mycophenolic mofetil does not cause the drastic change of the binding of FK506 and MPA with human plasma proteins.

Antibiotics, Antineoplastic↗
PubMed1994

Effects of non-MHC background genes on the induction of CD4+ T cells that prevent rejection of a highly immunogenic tumor, FBL-3.

This study showed that non-MHC genes common to (DBA/2 H-2d) and (DBA/1 H-2q) gave rise to suppressor T (Ts) cells in the hybrid F1 mice between C57BL/6 (B6) strain in the anti-FBL-3 tumor responses. FBL-3, a Friend virus-induced tumor cell line of B6 mouse origin, is highly immunogenic as shown by findings that syngeneic and hybrid F1 mice with several other inbred strains rejected up to 3 x 10(7) tumors cell inoculated s.c. and generated potent CTL responses after mixed lymphocyte tumor cell culture. In contrast to these mice, (B6 x DBA/2) and (B6 x DBA/1)F1 mice did not reject the tumor as the tumor doses increased. Progressive tumor growth in these F1 mice was blocked by an i.p. injection of cyclophosphamide (250 mg/kg) on day 10, but not on day 5, after tumor cell inoculation. Anti-CD4 (GK1.5) mAb exerted similar therapeutic effects against tumor when given twice, between day 0 and 10, whereas the additional injection of anti-CD8 mAb enhanced the tumor growth in mice that otherwise rejected the tumor. Thus, in the response of (B6 x DBA/2)F1 mice to FBL-3 tumor cells, CD4+ Ts seemed to down-regulate the immunologically mediated regression of the tumor produced by CD8+ CTL. This was evidenced by limiting dilution culture analyses, which showed that the frequency of an FBL-3-specific CTL precursor in the (B6 x DBA/2)F1 mice that rejected the tumor with anti-CD4 mAb was approximately 7- to 9-fold higher than that in mice in which the tumor regressed spontaneously.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Fine structure of a virus-encoded helper T-cell epitope expressed on FBL-3 tumor cells.

Antigen peptide fn20 representing Friend murine leukemia virus env122-141 (DEPLTSLTPRCNTAWNRLKL) is recognized by two independent Friend virus-induced, FBL-3 tumor-specific helper T-cell (Th) clones. We isolated more Th clones from mice immunized with fn20 peptide. We examined the fine structure of the peptide required to activate a large group of fn20-specific Th clones. A systematic analysis of peptides of decreasing lengths eliciting Th proliferation defined the minimum core length as 13 amino acids (LTSLTPRCNTAWN). Functional proliferation and competition assays with variant peptides with alanine substitutions permitted the assignment of five peptide residues in two major histocompatibility complex-interacting and three T-cell-receptor-interacting sites. Th clones were different in their reactivities toward peptides of various lengths and the variant peptides.

Amino Acid Sequence↗
PubMed1993

Interferon-gamma-producing tumor induces host tumor-specific T cell responses.

We investigated the mechanism of host immune responses against two interferon-gamma (IFN-gamma) gene-transduced tumors, plasmacytoma MOPC104E(Mu gamma) and mammary cancer SC115(K gamma), which originally had weak immunogenicity. Both IFN-gamma-producing tumor cells had reduced tumorigenicity and were rejected by syngeneic mice. The rejection was completely blocked by in vivo treatment with anti-CD8 or anti-IFN-gamma monoclonal antibodies. While anti-CD4 monoclonal antibody also blocked the rejection of SC115(K gamma), it enhanced the initial tumor growth of MOPC104E(Mu gamma). Specific protection against subsequent challenge with the respective parental tumor cells was demonstrated in mice which rejected the IFN-gamma-producing tumor cells. Cultured lymphocytes derived from immunized mouse spleens had cytotoxic T cell activity against parental tumor cells, as well as against cells that produced IFN-gamma. These findings indicate that the antitumor effects are mediated by cytotoxic T cells and, partly, by helper T cells, and that locally secreted IFN-gamma plays an important role in generating these effector cells.

Animals↗
PubMed1993

Hepatocellular carcinoma associated with chronic Schistosoma mansoni infection in a chimpanzee.

Hepatocellular carcinoma associated with chronic Schistosoma mansoni infection in a chimpanzee, estimated to be a 12-year-old and born in West Africa, is reported. The hepatic tumor appeared as a solitary firm nodule, and histological examination revealed well-differentiated hepatocellular carcinoma with a trabecular pattern. Hepatitis B virus and hepatitis C virus infections were excluded by serological testing in that animal. This is the first report of hepatocellular carcinoma in the chimpanzee with schistosomiasis.

Animals↗
PubMed1993

[Cancer immunotherapy by murine bladder cancer cells transfected with mouse interferon-gamma gene].

We established constitutively an interferon-gamma (IFN-gamma) producing cell line (MBT2/gamma) from a mouse bladder cancer cell line (MBT2) by retroviral transfer of a mouse IFN-gamma cDNA. Although the in vitro cell growth of these cells was unaffected by the IFN-gamma production, their subcutaneous tumor growth in syngeneic C3H/He mice was different; MBT2/gamma tumor growth was more strongly suppressed (3/20) than that of MBT2 (10/10). MBT2/gamma tumor growth was observed in nude mice (6/6). The mice immunized with MBT2/gamma were resistant to tumor growth of the parental cells (7/9; 77%), but permitted the growth of another kind of C3H/He tumor line. These findings indicate that the reduced tumorigenicity of the IFN-gamma producing line was due to the augmented specific antitumor immunity, probably as a result of the immunomodulatory effects of the IFN-gamma derived from the tumor.

Animals↗
PubMed1992

Factors influencing the response and survival of patients with liver metastases from breast cancer receiving OK-432-combined adoptive immunotherapy.

The response and survival of 26 patients with liver metastases from breast cancer, who received OK-432-combined adoptive immunotherapy from 1984 to 1990, were evaluated. OK-432-combined adoptive immunotherapy was comprised sequential treatment via the hepatic artery with a streptococcal preparation, OK-432 (1-5 KE), and adoptive transfer of lymphocytes expanded in T-cell growth factor and sonicated tumor extract antigen. Seventeen (65%) patients responded to the therapy. The median survival time of all patients after treatment was 13 months (range, 2-63 months). Of the 20 prognostic factors analyzed, performance status (PS) alone was related to response (P less than 0.01). The response rate of the patients with a PS of 0-2 was 83% but only 25% in those with a PS of 3 or 4. In univariate analysis, 11 factors significantly influenced the survival: tumor response; size of primary tumor; menopausal status; PS; serum bilirubin, albumin, lactate dehydrogenase and glutamate-oxalate transaminase (aspartate aminotransferase); the extent of liver involvement; and the number and the proliferation rate of transferred lymphocytes. The MST was 22.8 months for the responders versus 2.8 months for the nonresponders (P less than 0.01). In multivariate analysis, the most important factor associated with survival was the tumor response, as well as PS, liver involvement, lactate dehydrogenase and albumin. These results suggest that OK-432-combined adoptive immunotherapy can be considered a candidate for a randomised control study and these factors should be used for stratification.

Breast Neoplasms↗
PubMed1992

Therapeutic and life-prolonging effect of intrapleural injection with a streptococcal preparation, OK-432, and IL2-cultured effusion lymphocytes to breast cancer patients with malignant pleural effusion.

We developed a local AIT using PEL cultured with TCGF combined with preadministration of OK-432. Twenty-six patients of breast cancer with pleural effusion have been treated with this therapy since 1983. PEL expanded and tumor cells collapsed by day 9 in culture with TCGF. Cultured PEL possessed significantly higher cytotoxic activity against autologous tumor cells than PBL cultured in the same condition (p less than 0.05), but there was no difference between their cytotoxic activities against K562. The proliferation rate of PEL obtained after intrapleural administration of OK-432 was higher than that obtained before OK-432 (p less than 0.01). Moreover, the cytotoxic activities against both autologous tumor and K562 of cultured PEL obtained after OK-432 administration was significantly (p less than 0.05) higher than those cultured PEL obtained before. Cultured PEL (1 x 10(8)-6 x 10(9)) were transferred into the pleural cavity after the intrapleural administration of OK-432 (1-5 KE). The volume of pleural effusion increased temporarily after the administration of OK-432 but significantly (p less than 0.01) decreased after AIT. Tumor cells disappeared cytologically in 22 patients at the last puncture of pleural effusion. Pleural effusion disappeared completely in 19 of 26 patients and decreased by more than 50% in volume in 6 patients. Performance status improved in 22 patients. The response rate for OK-432-combined AIT in the present study was 96%. The survival period of the patients treated by OK-432-combined AIT in this trial was significantly (p less than 0.002) prolonged compared to that of the patients receiving chemotherapy alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

A murine plasmacytoma MOPC 104E resistant to cyclophosphamide is resistant to immunotherapy.

A murine plasmacytoma MOPC 104E (MOPC) is highly sensitive to chemotherapeutic agents such as cyclophosphamide and mitomycin C as well as to immunotherapy (OK-432-combined adoptive immunotherapy using interleukin-2-cultured killer cells). In the present study, we prepared cyclophosphamide-resistant MOPC cells (MOPC-CPA/R) by serial in vivo passage of tumor cells following cyclophosphamide treatment. The in vivo sensitivity of MOPC-CPA/R to mitomycin C or to immunotherapy (OK-432-combined adoptive immunotherapy) was significantly decreased compared to the parent MOPC. In vitro experiments showed that MOPC-CPA/R were more resistant (five-fold) to lysis by cultured immune spleen cells than MOPC. Inhibition of the lytic activity of cultured immune spleen cells against MOPC was significantly increased (P less than 0.05) by the addition of unlabeled MOPC compared to unlabeled MOPC-CPA/R. These results suggest that MOPC-CPA/R express weaker antigenicity than MOPC. However, the transfer of immune spleen cells cultured with tumor extract derived from MOPC-CPA/R significantly prolonged the survival of MOPC-CPA/R-inoculated mice. Thus, by repeated cyclophosphamide treatment, tumor cells with low-antigenicity were selected. These tumor cells had lower sensitivity to another chemotherapeutic agent and immunotherapy. Such an immunological response may play an important role in cancer therapy.

Animals↗
PubMed1990

Effect of heat treatment on tumor cells and antitumor effector cells.

We examined the effects of heat treatment on tumor cells and antitumor effector cells in order to investigate the combined effects of hyperthermia and immunotherapy including adoptive immunotherapy. Plasmacytoma MOPC104E syngeneic to BALB/c mice was used as the tumor cell line, while fresh spleen cells immunized to MOPC104E (IM-FSC) and interleukin-2-cultured lymphocytes induced in vitro from IM-FSC (CL) were used as the effector cells. Tumor cells or effector cells were heat-treated in a water bath at 42 degrees C for 30 or 60 min. Tumor cells heat-treated at 42 degrees C for 30 min grew temporarily and then regressed in the tumor transfer test, whereas untreated tumor cells showed no regression under any conditions. Furthermore, fresh spleen cells of mice inoculated with heat-treated tumor cells from regressed tumors showed marked tumor-neutralizing activity. The antitumor effects of CL were markedly inhibited by heat treatment according to the results of the tumor-neutralizing test and the 51Cr release assay, whereas heat treatment had little influence on the antitumor activity of IM-FSC. However, the neutralizing activity of effectors and the killing activity of CL against heat-treated tumor cells were both markedly augmented, since the susceptibility of the tumor cells to the antitumor effector cells was augmented by heat treatment. These results suggest that heat treatment of tumor cells augments the antitumor effects of IM-FSC and CL, hence we speculate that hyperthermia augments the effects of immunotherapy including adoptive immunotherapy.

Animals↗