Biomedical subjects

Koji Tsuboi

Publications and source records attributed to Koji Tsuboi.

28 records · Page 2Linked to original sources

PubMed2004

Intratumoral injection of IL-2-activated NK cells enhances the antitumor effect of intradermally injected paraformaldehyde-fixed tumor vaccine in a rat intracranial brain tumor model.

Combined therapy with a fixed-tumor cell vaccine and intratumoral injection of NK cells induced strong tumor regression of rat glioma. Rat 9L glioma cells were inoculated into syngeneic male rats at the flank (subcutaneous tumor model) or at the basal ganglia of the right hemisphere (intracranial tumor model). Rats were intradermally injected three times with vaccine comprising fixed 9L cells, IL-2- and GMCSF-microparticles, and tuberculin prior to (protective studies) or after (therapeutic studies) challenge with live 9L cells. In the protective studies, the vaccine alone achieved significant tumor growth inhibition and elongation of mean life span in both the subcutaneous and intracranial tumor models. No therapeutic effect was observed in the intracranial tumor model with the vaccine alone. However, intratumoral injection of rat NK cells strongly assisted the therapeutic effect of the vaccine in the brain tumor model and resulted in a statistically significant elongation of life span. We propose that intratumoral injection of NK cells may not only kill brain tumor cells directly, but also trigger a strong immune response in the focal lesion of the brain after vaccination.

Animals↗

PubMed2004

In vivo radioprotection of mice by 3-methyl-1-phenyl-2-pyrazolin-5-one (edaravone; Radicut), a clinical drug.

Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one; Radicut) is a brain-protecting agent used clinically to treat acute ischemic stroke with a reaction mechanism of free radical scavenging. Since the initial stage of radiation damage involves the formation of free radicals, edaravone is expected to be effective in preventing lethal damage from ionizing radiation. In the present study, we used mice to examine in vivo the radioprotective effect of edaravone on whole body X-ray irradiation. A solution of edaravone was administered intraperitoneally to C3H mice (male, 10 weeks old), and they were irradiated with a total dose of 8.0 Gy. Edaravone exhibited dose-dependent and injection time-dependent radioprotection. When injected 30 min before the X-ray irradiation, it had the greatest radioprotective effect, whereas an injection after the irradiation showed no protective effect. The LD(50/30) was about 8.8 Gy for edaravone-injected mice and 6.6 Gy for control mice, yielding a DRF for edaravone (450 mg/kg bw) of 1.3. Edaravone decreased the body temperature transiently about 3-6C, but this did not seem to be responsible for the radioprotection. Since the radioprotection was observed only when the reagent was administered before the irradiation, the primary action of edaravone might be the quenching of free radicals with a short lifetime generated by the irradiation.

Animals↗

PubMed2003

Effects of local injection of ex vivo expanded autologous tumor-specific T lymphocytes in cases with recurrent malignant gliomas.

PURPOSE: The aim of this report was to indicate both the advantages and disadvantages of local cell transfer therapy using ex vivo expanded autologous tumor-specific T lymphocytes (ATTLs) for recurrent cases of malignant gliomas. EXPERIMENTAL DESIGN: Subjects are 10 cases of malignant gliomas consisting of 7 cases of glioblastoma multiforme, 2 cases of anaplastic astrocytoma, and 1 case of anaplastic oligoastrocytoma. All cases were recurrences. ATTLs were induced by coculturing peripheral blood mononuclear cells with autologous tumor cells in medium containing interleukin-1, -2, -4, and -6 and administered into the local tumor site in total numbers of 3-247 x 10(7) cells. As end points, tumor response and survival time were analyzed observing clinical state. RESULTS: Five cases responded to this therapy (namely, one case showed complete remission, and four cases had a partial response). There were three cases of no change, and two cases of progressive disease. The overall tumor response rate was 50%. No complications were noticed, except for two cases of minor local hemorrhage and eight cases of temporary fever. Nine cases died of further tumor progression, and one case died of aspiration pneumonia, and the cause-specific survival analysis indicates that the median survival time was 5 months from the initial ATTL injection. CONCLUSIONS: The results suggest that local administration of ATTLs is effective in recurrent malignant gliomas in that it demonstrated a high benefit:risk ratio with minor side effects. Although its antitumor effect may be temporary in some advanced cases, it is highly possible that the tumor could be stabilized when conditions are optimal.

Adult↗

PubMed2003

Reduction of nitroxides and radioprotective ability in glioblastoma cells.

Electron spin resonance (ESR) analyses were performed to clarify whether glioblastoma cells scavenge hydroxyl radicals (*OH) generated by x-ray irradiation. The rate of bioreduction of nitroxides by three human glioblastoma cells was also evaluated by the same technique and compared with their x-ray sensitivity. Aerated culture media containing 200mM of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) with or without U87MG cells were irradiated with x-rays at a dose of 20Gy. ESR was measured immediately after each irradiation. Continuous changes of the ESR spectra of 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (Tempol) were analyzed in cell suspensions of TK1, U87MG, and A172 at a concentration of 1.0 x 10(7) cells/ml containing 5 microM Tempol. As a result, the signal of DMPO-OH in the U87MG cell suspension decayed faster than that in the control culture media without cells, and the rate of bioreduction of Tempol in each glioblastoma cell suspension was correlated with the x-ray sensitivity defined from the colony-forming assay in those cell lines. It was indicated that the resistance of glioblastoma cells to ionizing radiation could be closely related to their ability to scavenge radical species generated by ionizing radiation.

Cell Line, Tumor↗

PubMed2003

Anti-vascular endothelial growth factor antibody and nimustine as combined therapy: effects on tumour growth and angiogenesis in human glioblastoma xenografts.

We evaluated the effectiveness of vascular endothelial growth factor (VEGF) blockade alone and in combination with 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU, nimustine), a cytotoxic agent commonly used in the treatment of malignant gliomas, to eradicate tumors of human glioblastoma cell lines implanted in SCID (severe combined immunodeficiency) mice. ACNU, but not cisplatin and etoposide, elevated VEGF expression in a glioma cell line in vitro. VEGF antibody alone inhibited glioma growth in vivo as a result of angiogenesis inhibition. The combination with ACNU resulted in an additive effect for inhibition of glioma growth. ACNU also induced VEGF up-regulation in glioma tissues, which was decreased with VEGF antibody treatment. One of the mechanisms of the additive effect of the VEGF antibody and ACNU combination is the blockade of VEGF up-regulation induced by ACNU. As such, the combination of antiangiogenic therapy with conventional therapy is promising for glioma treatment in the future.

Animals↗

PubMed2003

ESR spin trapping of hydroxyl radicals in aqueous solution irradiated with high-LET carbon-ion beams.

The aim of this study was to quantify the hydroxyl radicals (*OH) produced when aqueous solutions are decomposed by high-linear energy transfer (LET) 290 MeV/nucleon carbon-ion beams using an electron spin resonance (ESR) spectrometer. Aerated cell culture medium containing 200 mM 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) was irradiated with doses of 0 to 20 Gy with an LET of 20 to 90 keV/ micro m. We were able to obtain ESR spectra 10 min after irradiation, and the formation of *OH and hydrogen atoms was confirmed by radiolysis of deuterium oxide and ethanol containing DMPO. Our results showed that the yield of *OH by carbon-ion radiolysis increased in proportion to the absorbed dose over the range of 0 to 20 Gy. Furthermore, we discovered that the yield of *OH decreased linearity as LET increased logarithmically from 20 to 90 keV/ micro m. The generation of *OH by carbon-ion radiolysis at LETs of 20, 40, 60, 80 and 90 keV/ micro m was 64, 58, 52, 49 and 50%, respectively, of that for low-LET X radiolysis. These unique findings provide a further understanding of the indirect effect of high-LET radiation.

Carbon↗

PubMed2003

Serial neuroimaging of encapsulated chronic intracerebral hematoma with repeated hemorrhage--case report.

A 69-year-old woman presented with headache and short memory disturbance. Computed tomography (CT) demonstrated a small cystic mass lesion in the left temporal lobe. CT and magnetic resonance imaging showed that this lesion enlarged with repeated hemorrhages, associated with progressive amnesia and headache during 3 years follow up. Surgery demonstrated a well-demarcated hard mass lesion in the medial temporal lobe through a transcortical approach after opening left sylvian fissure. The lesion was located entirely in the brain parenchyma and was removed en-bloc after cutting some capillary-like vessels on the capsule. The histological diagnosis was encapsulated old hematoma. The histological findings suggested that expansion of the lesion was due to multiple bleedings from the sinusoidal vessels in the capsule fed by small feeding arteries. The mass effect due to the expansion of the encapsulated hematoma caused progressive short-term amnesia and headache, which were completely resolved by the surgical removal.

Aged↗

PubMed2002

Selective expansion of human natural killer cells from peripheral blood mononuclear cells by the cell line, HFWT.

An anchorage-dependent Wilms tumor cell line HFWT was found to stimulate selective and remarkable expansion of human natural killer (NK) cells from human peripheral blood mononuclear cells (PBMC). After PBMC of healthy donors were cultured on irradiated HFWT cells for 10 - 21 days, the lymphocytes expanded 58- to 401-fold. This NK cell expansion required direct contact of PBMC with live, but not fixed, HFWT cells. The PBMC from an end-stage brain tumor patient also expanded 156-fold, whereas those cultured with irradiated NK-sensitive K562 grew only 30.5-fold. CD16+ CD56+ NK cells accounted for more than 70% of the population expanded on HFWT cells. No essential difference in expression of NK receptors was observed in the expanded NK cells on HFWT and K562 and without feeder cells. The expanded NK cells killed not only fresh HFWT cells but, unexpectedly, also MHC class I-expressing autologous brain tumor cells at an effector/target ratio of 4 for 24 h. These results will contribute to the development of a large-scale preparation method for human NK cells, which will aid studies of NK cell biology and possible treatment of brain tumors.

Animals↗

PubMed2002

Chondroblastoma of the temporal base with high mitotic activity.

A 24-year-old man presented with a rare chondroblastoma of the temporal base manifesting as local pain accompanied by difficulty in opening the mouth. Gross total removal was achieved at initial surgery, but the tumor demonstrated rapid and destructive regrowth from a very small residual volume without definite histological malignant transformation. Growth activity estimated by MIB-1 staining increased spontaneously from 2.5% at the initial operation to 18.7% at recurrence. Further extensive radical tumor removal by surgeons from multiple disciplines was performed. The patient has been free of recurrence for 3 years without radiotherapy. Chondroblastoma of the temporal bone is widely accepted as a benign tumor and regrowth after gross total removal is very rare. However, some cases of chondroblastoma have potentially high mitotic activity.

Adult↗

PubMedDate not supplied

Autologous natural killer cell therapy for human recurrent malignant glioma.

BACKGROUND: Natural killer (NK) cells are highly efficient in the cellular immune response against malignant tumors without restriction of major histocompatibility complex. However clinical studies using autologous NK cells have been reported in only a very limited number of cases, due to the fact that selective NK expansion is difficult to achieve in this patient population. Here, we report the results of adoptive immunotherapy in patients with recurrent malignant gliomas using autologous NK cells that were expanded ex vivo by a novel method. PATIENTS AND METHODS: Peripheral blood mononuclear cells (PBMCs) were prepared from patients with malignant gliomas, and were co-cultured with an irradiated human feeder cell line (HFWT) in RHAM-alpha medium supplemented with 5% autologous plasma and interleukin-2. The resulting NK cell-rich effector cells were injected into 9 patients (16 courses) with recurrent malignant glioma (6 cases of WHO grade-3 glioma and 3 cases of grade-4 glioma). RESULTS: The mean frequency of NK cells among lymphocytes was 82.2 +/- 10.5%. A combination of focal and intravenous injections was peformed in 10 courses. Intravenous injection alone was performed in 6 courses. Further, intravenous injection of low-dose interferon beta (6x10(6) IU/week) was performed as an adjuvant therapy in all courses to achieve maximum benefit for enrolled patients. Clinical evaluation demonstrated 3 PR, 2 MR, 4 NC and 7 PD in a total of 16 courses of treatment. Severe neurological toxicity was not observed in any of the patients. CONCLUSION: It was demonstrated that NK cell-rich effector cells were expanded ex vivo from PBMCs in all nine cases of recurrent malignant glioma and that NK cell therapy was safe and partially effective in patients with recurrent malignant gliomas.

Adult↗