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S Ozeki

Publications and source records attributed to S Ozeki.

158 records · Page 9Linked to original sources

Squamous cell carcinoma of the oral cavity derived from a skin graft: a case report.

A case of oral cancer that had derived from a 19-year skin graft on the left buccal mucosa is reported. The patient had had three previous operations due to squamous cell carcinoma, erosion, and squamous cell carcinoma of the left buccal mucosa, respectively. In the last two operations, skin was transplanted, and the present cancer is believed to have derived from the latter one. The tumor was resected, and a new skin was grafted. In situ hybridization of human papilloma virus (HPV) was carried out; the HPV 16 DNA could not be detected in the specimen. Eight months later, a cervical lymph node metastasis was detected; thus, a radical neck dissection was performed.

Aged↗

Comparison of in vitro antimicrobial activity of AM-1155 with those of tosufloxacin and fleroxacin against clinical isolates of Neisseria gonorrhoeae harboring quinolone resistance alterations in GyrA and ParC.

The in vitro antimicrobial activities of AM-1155, a new fluoroquinolone, tosufloxacin and fleroxacin were tested against 55 clinical isolates of Neisseria gonorrhoeae using the agar dilution method. In our previous study, all the strains had been examined for mutations in the region corresponding to the quinolone-resistance determining region of the Escherichia coli gyrA gene and the analogous region of the parC gene, and tested for susceptibility to ciprofloxacin. In this study, the 55 isolates of N. gonorrhoeae were assigned to one of three categories based on the presence or absence of alterations in GyrA and ParC. In each category, the antimicrobial activity of AM-1155 against the isolates was compared with those of tosufloxacin and fleroxacin. The MICs of AM-1155 for 11 highly fluoroquinolone-resistant isolates with alterations in both GyrA and ParC ranged from 0.06 to 1.0 microgram/ml. The MICs inhibiting 50% (MIC50) and 90% (MIC90) of these isolates were 0.125 and 1.0 microgram/ml, respectively. The MICs of AM-1155 for 20 moderately fluoroquinolone-resistant isolates with alterations only in GyrA ranged from 0.03 to 0.25 microgram/ml (MIC50, 0.06 microgram/ml; MIC90m, 0.125 microgram/ml). The MICs of AM-1155 for 24 of the quinolone-susceptible isolates without alterations in either GyrA or ParC ranged from 0.004 to 0.03 microgram/ml (MIC50, 0.008 microgram/ml. MIC90, 0.015 microgram/ml). There were significant differences between the MIC distribution of AM-1155 and each corresponding MIC distribution of tosufloxacin and fleroxacin in these three categories to which the 55 isolates were assigned (p < 0.05). Based on the MIC90S of the tested fluoroquinolones, AM-1155 was two- and eightfold more active against the highly fluoroquinolone-resistant isolates than tosufloxacin and fleroxacin, respectively. Against the moderately fluoroquinolone-resistant isolates, AM-1155 was four- and sixteenfold more active than tosufloxacin and fleroxacin, respectively. Against the quinolone-susceptible strains, AM-1155 was also two- to fourfold more active than the other fluoroquinolones. Overall, AM-1155 exhibited more potent in vitro activity against both quinolone-resistant and quinolone-susceptible isolates of N. gonorrhoeae than tosufloxacin and fleroxacin. In ciprofloxacin treatment failures of gonorrhea at single doses of 500 mg. MICs for the causative organisms have ranged from 1.0 to 16.0 micrograms/ml. The MICs of AM-1155 for the isolates harboring quinolone resistance-associated genetic alterations, including strains exhibiting ciprofloxacin MICs of 2.0 and 8.0 micrograms/ml, still ranged from 0.03 to 1.0 microgram/mL A single-dose study in humans has demonstrated higher peak serum concentrations and longer half-lives of AM-1155, resulting in the AUC0-00 values of AM-1155, which are threefold greater than those of ciprofloxacin at the single doses of 400 and 600 mg. Because of its potent in vitro antimicrobial activity and advantageous pharmacokinetic behavior, AM-1155 may be a clinically useful agent for treating gonorrhea including that caused by quinolone-resistant strains.

Anti-Infective Agents↗

Mitochondrial genotypes and radiation-induced micronucleus formation in human osteosarcoma cells in vitro.

We investigated whether or not the mitochondrial genotypes affect radiation-induced micronucleus (MN) formation. For that purpose, the rho+, KT1 and rho0 human osteosarcoma cell lines were used, which carry the wild-type mitochondrial DNA (mtDNA), the tRNALys mutant mtDNA and no mtDNA, respectively. Despite no significant difference in the clonogenic radiosensitivity, the rho+, KT1 and rho0 cells exhibited high, intermediate and low radiosensitivities, respectively, to the MN induction in cytokinesis-blocked binucleated cells. Such differential MN inductions were correlated with high, intermediate and low levels of cellular ATP in the rho+, KT1 and rho0 cells, respectively, but not exactly with ROS production. Antimycin A that inhibits the respiratory complex III reduced the rate of radiation-induced MN induction in the rho+ and KT1, but not rho0 cells. Thus, the functional status of the mtDNA to produce ATP appears to play a significant role for radiation-induced MN.

Adenosine Triphosphate↗

Differences in the biological effects of in vitro irradiation by 65 MeV protons and 137cesium gamma-rays.

Using the irradiation system constructed for research in radiation biology, we have investigated the differences in the biological effects of in vitro irradiation by 65 MeV protons and by 137Cs gamma-rays. Survival curves were generated using V79 cells. The effects on biological parameters (SF2, RBE) of protons were greater than gamma-rays. Furthermore, 3H-thymidine incorporation in KOSC-3 cells, which display the p53 gene mutation, was inhibited by protons much more than by gamma-rays. On the other hand, in bleomycin-sensitive SCCKN cells, 3H-thymidine incorporation decreased more than in bleomycin-resistant SCCTF cells, however, both were inhibited by protons much more than by gamma-rays. In this study, the biological parameters and 3H-thymidine incorporation caused by 65 MeV protons were more severe than those caused by 137Cs gamma-rays.

Animals↗

Mitochondrial DNA influences radiation sensitivity and induction of apoptosis in human fibroblasts.

BACKGROUND: We aimed to assess the role of mitochondrial DNA (mtDNA) in ionizing irradiation. MATERIAL AND METHODS: We examined three human fibroblast cell lines either lacking mtDNA (rho 0 cell), carrying mutant mtDNA (syn cell) or normal mtDNA (rho + cell). Cell survival curves were generated with colony formation and dye exclusion tests. Cell cycle analysis and apoptosis assay were performed by flow cytometry. RESULTS: The rho 0 cell line showed a stronger resistance to irradiation than the other two cell lines when assessed by the colony formation assay. In the dye exclusion test, the rho 0 cells revealed a superior cell viability among the cell lines after 5 and 8 Gy irradiation. The rho 0 cells underwent apoptosis at lower rates than the other two cell lines after 2, 5 and 8 Gy irradiation, and showed no alterations in the cell cycle distribution among them. CONCLUSION: mtDNA plays an important role in radiation sensitivity and induction of apoptosis.

Apoptosis↗

Role of mitochondrial DNA in radiation exposure.

PURPOSE: To evaluate the role of mitochondrial DNA (mtDNA) following exposure to ionizing irradiation. MATERIALS AND METHODS: We examined two human osteosarcoma cell lines either lacking mtDNA (143B.rho(0)206; rho0 cells) or having normal mtDNA (143B.TK-; rho+ cells). Cell survival curves were generated by using colony formation and micronucleus assay. The delay in population doubling time after irradiation was evaluated with dye exclusion tests. RESULTS: No significant difference was seen between rho+ and rho0 cell lines in colony formation assay. In micronucleus assay, rho0 cells showed a significantly lower rate of micronucleus formation. The ratios of binucleated cells with micronuclei were 0.49 for rho+ cells and 0.25 for rho0 cells (p=0.005). In the dye exclusion test, rho0 cells revealed a delay of about 1.6 times in population doubling time compared with the control after 5 Gy of irradiation, similar to the 1.7 times of rho+ cells. CONCLUSION: In the human osteosarcoma cell line 143B.TK-, mtDNA does not influence clonogenic survival and delay of population doubling time after irradiation. However, the difference in micronucleus formation shows that mtDNA influences DNA damage after radiation exposure.

Cell Division↗

Modified Inoue applicator for endometrial brachytherapy.

The Inoue applicator (3 channels) for endometrial cancer with a microSelectron-HDR was modified to enable both intrauterine and vaginal treatments to be done at the same time. The applicator is described together with a case report.

Adenocarcinoma↗

Modified ovoid applicator for intracavitary radiation therapy with a Selectron-MDR or microSelectron-HDR.

A modified ovoid applicator for intracavitary radiotherapy was developed for Japanese and other Asian women. It has more variations of smaller sized ovoids than the original rigid standard applicator of the Selectron-MDR and microSelectron-HDR. In addition, application of the ovoid pair and tandem flange is easy due to the flat surface of the inner aspect of the ovoid pairs, which prevents slippage of the ovoids and flange. The applicator is described together with source loading and dose distribution.

Asia↗

Effect of hepatocyte growth factor on radiation response of HeLa, V79, CHO and primary cultured parenchymal hepatocyte in vitro.

Hepatocyte growth factor (HGF) is a multipotent cytokine enhancing regeneration of injured organs as liver, kidney and lung after injury. HGF enhances proliferation of various type of cells, inhibits proliferation of carcinoma cells, enhances motility of epithelial cells. We examined three cell lines (CHO, HeLa, V79) and primary cultured normal rat parenchymal hepatocytes to determine the effect of HGF on radiation response. HGF diminished survival of CHO and V79 cells determined by colony formation assay, whereas no significant change of survival was found in HeLa cells. No synergistic changes of survival were found when these three cell lines were irradiated with the addition of HGF. Thus, HGF did not enhance the radiation effect. We also analyzed the impact of irradiation with HGF on primary cultured normal rat parenchymal hepatocytes. At first, the release of glutamic-oxaloacetic amino-transaminase (GOT) in the supernatant was estimated. Irradiation (40 Gy) with or without HGF did not change GOT release in acute phase by 4 days after irradiation compared with the unirradiated control. Second, the DNA synthesis of rat parenchymal hepatocytes was analyzed using radioactive iodine-labeled deoxyuridine incorporation. HGF counteracted the suppression of DNA synthesis induced by irradiation. Thus, HGF may act as a mitogen even for irradiation-damaged normal cells.

Animals↗

Lack of effect of hepatocyte growth factor on bone marrow suppression induced by total body irradiation in the rat.

We examined the role of hepatocyte growth factor (HGF) on the bone marrow suppression by irradiation, by analyzing peripheral blood counts 2 weeks after 7 Gy of total body irradiation in rats. The rats underwent two weeks of continuous intraperitoneal human recombinant HGF injection (50 mg/day) from one day before irradiation using an Alzet osmotic pump. Red blood cell, white blood cell, and platelet counts did not increase with response to administration of HGF. Thus HGF does not show protection against myelosuppression caused by total body irradiation.

Animals↗

Heparin induces rapid and remarkable elevation of hepatocyte growth factor/scatter factor during trans arterial embolization of renal cell carcinoma.

BACKGROUND: Our aim was to determined the change of serum hepatocyte growth factorl scatter factor (HGF) before and after transarterial embolization (TAE) for renal cell carcinoma (RCC). MATERIALS AND METHODS: We examined serum HGF levels in two patients. RESULTS: Serum HGF levels rapidly increased to six-fold higher levels immediately after heparin-injection even before embolization. Serum HGF then decreased to below 1.0 ng/ml at 6 hours after the procedure. The second peak (a two-fold increase) appeared 1-3 days after TACE. The first increase may have been due to the injection of heparin which releases HGF from the cell-surface and extracellular matrix. HGF is a pleiotropic cytokine which has a potential to enhance cell motility and angiogenesis related to tumor progression and the first larger elevation of serum HGF is enough to make a physiological effects. CONCLUSION: Therefore, we should remind the physiological influence of heparin injection not only to prevent of clotting.

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