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Biomedical subjects

Y Furusawa

Publications and source records attributed to Y Furusawa.

At least 19 recordsLinked to original sources

Complex-type chromosomal exchanges in blood lymphocytes during radiation therapy correlate with acute toxicity.

The new method of chemical-induced premature chromosome condensation combined with fluorescence in situ hybridization was used to analyze chromosomal damage in peripheral blood mononuclear lymphocytes of patients undergoing radiation treatment for esophageal cancer with high-energy X-rays or accelerated carbon ions at the National Institute of Radiological Sciences (Chiba, Japan). Total number of aberrant cells correlated with radiation field size, but no correlation was found with acute toxicity. A high frequency of complex-type exchanges were also recorded. This aberration type presented a high individual variability, and correlated well with the acute morbidity. Cytogenetic analysis by interphase chromosome painting is proposed as a useful tool for monitoring normal tissue effects during radiotherapy.

Aged

WAF1 accumulation by carbon-ion beam and alpha-particle irradiation in human glioblastoma cultured cells.

PURPOSE: There have been no reports about the effects of heavy-ion beams on the expression of the WAF1 gene, although ionizing radiation such as y-rays and X-rays is well known to induce WAF1 (p21/CIP1/sdi1) gene expression in a p53-dependent manner. In the present study, it was examined whether WAF1 accumulation was induced after carbon-ion (C-) beam or alpha-particle irradiation in four glioblastoma cell lines. MATERIALS AND METHODS: A colony assay for radiosensitivity and Western blot analysis of WAF1 were applied to two human glioblastoma cell lines, A-172 bearing wild-type p53 (wtp53) and T98G bearing mutated p53 (mp53). A-172/neo and A-172/mp53 were transfected with a control vector (containing only a neo selection marker) and a mp53 expression vector respectively. RESULTS: The amount of WAF1 increased markedly after X-ray irradiation in A-172 and A-172/neo cells but not in T98G and A-172/mp53 cells. The level of WAF1 reached a plateau at 3-10 h after X-ray irradiation at 5 Gy in A-172 and A-172/neo cells. Likewise, the levels of WAF1 in A-172 and A-172/neo cells reached a plateau at 3-10 h and 6-24 h after C-beam (3.0 Gy) and alpha-particle (4.5 Gy) irradiation respectively. The amount of WAF1 increased markedly in a dose-dependent manner 10 h after X-ray, C-beam or alpha-particle irradiation in A-172 and A-172/neo cells but not in T98G or A-172/mp53 cells. In addition, cell survival assay showed that these cell lines were most sensitive to C-beams, less sensitive to alpha-particles and least sensitive to X-rays at 10% survival. There was no difference in sensitivity among these cell lines against C-beam and alpha-particle irradiation whereas wtp53 cells (A-172 and A-172/neo) were more sensitive to X-rays than mp53 cells (A-172/mp53 and T98G). CONCLUSIONS: These results indicate that C-beams and alpha-particles induce p53-dependent WAF1 accumulation as well as is the case with X-rays, suggesting that WAF1 protein accumulation may not contribute to cell killing.

Alpha Particles

Biophysical characteristics of HIMAC clinical irradiation system for heavy-ion radiation therapy.

PURPOSE: The irradiation system and biophysical characteristics of carbon beams are examined regarding radiation therapy. METHODS AND MATERIALS: An irradiation system was developed for heavy-ion radiotherapy. Wobbler magnets and a scatterer were used for flattening the radiation field. A patient-positioning system using X ray and image intensifiers was also installed in the irradiation system. The depth-dose distributions of the carbon beams were modified to make a spread-out Bragg peak, which was designed based on the biophysical characteristics of monoenergetic beams. A dosimetry system for heavy-ion radiotherapy was established to deliver heavy-ion doses safely to the patients according to the treatment planning. A carbon beam of 80 keV/microm in the spread-out Bragg peak was found to be equivalent in biological responses to the neutron beam that is produced at cyclotron facility in National Institute Radiological Sciences (NIRS) by bombarding 30-MeV deuteron beam on beryllium target. The fractionation schedule of the NIRS neutron therapy was adapted for the first clinical trials using carbon beams. RESULTS: Carbon beams, 290, 350, and 400 MeV/u, were used for a clinical trial from June of 1994. Over 300 patients have already been treated by this irradiation system by the end of 1997.

Calibration

Measurements of the equivalent whole-body dose during radiation therapy by cytogenetic methods.

Estimates of equivalent whole-body dose following partial body exposure can be performed using different biophysical models. Calculations should be compared with biodosimetry data, but measurements are complicated by mitotic selection induced in target cells after localized irradiation. In this paper we measured chromosomal aberrations in peripheral blood lymphocytes during radiotherapy, and estimated the equivalent whole-body dose absorbed, by using the novel technique of interphase chromosome painting. Premature chromosome condensation was induced in stimulated lymphocytes by incubation in calyculin A, and slides were hybridized in situ with whole-chromosome DNA probes specific for human chromosomes 2 and 4. Reciprocal exchanges were used to estimate the equivalent whole-body dose, based on individual pre-treatment in vitro calibration curves. Equivalent whole-body dose increased as a function of the number of fractions, and reached a plateau at high fraction numbers. Chromosomal aberration yields were dependent on field size, tumour position and concurrent chemotherapy. Results suggest that interphase chromosome painting is a simple technique able to give a reliable estimate of the equivalent whole-body dose absorbed during therapeutic partial-body irradiation.

Aged

Association between G2-phase block and repair of radiation-induced chromosome fragments in human lymphocytes.

We have studied the induction of chromosomal aberrations in human lymphocytes exposed in G0 to X rays or carbon ions. Aberrations were analyzed in G0, G1, G2 or M phase. Analysis during the interphase was performed by chemically induced premature chromosome condensation, which allows scoring of aberrations in G1, G2 and M phase; fusion-induced premature chromosome condensation was used to analyze the damage in G0 cells after incubation for repair; M-phase cells were obtained by conventional Colcemid block. Aberrations were scored by Giemsa staining or fluorescence in situ hybridization (chromosomes 2 and 4). Similar yields of fragments were observed in G1 and G2 phase, but lower yields were scored in metaphase. The frequency of chromosomal exchanges was similar in G0 (after repair), G2 and M phase for cells exposed to X rays, while a lower frequency of exchanges was observed in M phase when lymphocytes were irradiated with high-LET carbon ions. The results suggest that radiation-induced G2-phase block is associated with unrejoined chromosome fragments induced by radiation exposure during G0.

Adult

[Sense of coherence, stressful life events and psychological health].

Aaron Antonovsky's Sense of Coherence (SOC), as a stable disposition of personality that serves as a major coping resource for the preservation of health, has been widely used in many studies. However, few empirical studies are conducted on the concept of SOC. We examined the stability of SOC and the buffering effect of SOC on the psychological health in dealing with stressful life events. The subjects were 200 adults randomly selected in Tokyo, and follow-up survey was conducted one year after the first survey. Goldberg's General Health Questionnaire (GHQ) was used for assessing psychological health. Antonovsky's SOC scale was translated into Japanese (and reverse translated) in this study. The test-retest reliability of SOC scale was 0.78. Cronbach's alpha was 0.91. The factors related to the SOC supported previous findings and Antonovsky's theory about the positive correlation with educational and economic status. In the follow-up survey, the subjects were also asked about the experience of 56 stressful life events (SLE) composed of four aspects of life during the previous year: personal, family, work and environment. The SLE was assessed through the total number and the weighted score. Contrary to the theory, the results showed that the SOC score has no intra-individual stability. The mean score of SOC in 1998 was 131.1 +/- 23.9, significantly lower than that in the previous year. When the subjects were divided into two groups based on a median 1997 score, the effect of SLE negatively affected SOC scores after one year among those who had a low SOC, although this effect was not observed among those who had a high SOC. The effect of SLE on changes of SOC was stronger among men compared to women. Also, the results showed the SOC was positively related to psychological health, and the buffering effect of SOC on the psychological health in dealing with stressful life events was only observed among men. Findings in this study suggest that SOC is variable for those with weak SOC if they experienced stressful life events. Also, the stressful life events differentially affect the SOC among men and women. The buffering effect was not sufficiently proven in this study. Methodological issues to confirm Antonovsky's theory are also presented.

Adult

Evidence for mRNA expression of vascular endothelial growth factor by X-ray irradiation in a lung squamous carcinoma cell line.

Vascular endothelial growth factor (VEGF) is a multipotent cytokine which plays an important role in various angiogenic conditions as well as in some tumor behaviors. Here we examined the induction of VEGF mRNA by X-ray irradiation in a lung squamous cell carcinoma cell line (RERF-LC-AI). Irradiating the cells with 15 Gy X-rays significantly increased the mRNA expression up to 2.5-fold of control at a post-irradiation time of 16-24 h. The induction of VEGF mRNA by X-ray irradiation was completely blocked by treating cells with either genistein (Src tyrosine kinase inhibitor) or H7 (protein kinase C inhibitor). This suggests that the mechanism of induction might be concerned with the pathway which triggers Src tyrosine kinase of the cell surface and the protein kinase C pathway.

Antineoplastic Agents

An increase in [3H]QNB binding by proton-beam irradiation in intact rat brain: an apparent positive cooperativity of binding.

After focal irradiation of rat brains with a beam of proton (dose, 30 Gy), [3H]quinuclidinyl benzilate (QNB) binding, both in vitro and in vivo, was measured, using either autoradiographic or tissue-dissection methods. No changes in in vitro [3H]QNB binding were seen in autoradiograms of brain slices from irradiated rat. The irradiated side of the brain showed a significant increase in [3H]QNB binding in vivo in the striatum and cerebral cortex 24 h after irradiation. This increase in binding was transient, and had almost disappeared 2 weeks after irradiation. These results indicate that early changes in receptor function as a results of radiation damage are only detected in in-vivo conditions. In the striatum of the intact rat brain, an apparent positive cooperativity of binding was observed, which was more pronounced on the irradiated side.

Animals

Evaluation of ischemic damage in the skeletal muscle with the use of electrical properties.

We performed experimental and clinical studies with measurement of electrical character in the skeletal muscle to assess ischemic damage and reperfusion injury in lower limbs. In 14 dogs, the bilateral hind limbs were squeezed at the inguinal region to make ischemia and they were reperfused after various intervals. Conductivity (G) of the skeletal muscles in hind limbs was measured with an LCR meter, which is an impedance analyzer. Change of G from 0 to 3 h of reperfusion (Delta3G) was calculated. G was decreased during ischemia and increased after reperfusion. In those whose Delta3G as more than 2.1 mS/cm, serum creatine kinase and aldolase at 10 h after reperfusion were correlated significantly (P < 0.01) to Delta3G. In patients with an abdominal aortic aneurysm (N = 3), arteriosclerosis obliterans (N = 1), or acute arterial occlusion (AAO, N = 1), G of lower extremities was measured from arterial clamp to declamp. Conductivity markedly increased after reperfusion and serum creatine kinase was the highest in the patient with AAO. We suggested that measurement of G may provide monitoring of ischemic and reperfused phase injury in the skeletal muscle and may be applicable to prediction of the skeletal muscular reperfusion injury.

Animals

Determination of erythema-effective solar radiation in Japan and Germany with a spore monolayer film optimized for the detection of UVB and UVA--results of a field campaign.

The available physical and biological broad-band radiometers designed to determine erythema-effective radiation do not show any response or over/underestimate the biologically effective radiation to a high extent in the ultraviolet (UV)A spectral region. The data presented in this paper demonstrate that the biological system used in this study is the first one to make possible measurements of erythema-effective radiation in the sun in the UVA and UVB spectral region. These measurements were performed with a spore-film filter system as well as with spectroradiometers. It was demonstrated that this biotechnological method could be used to determine exact values expressed as minimal erythemal dose (MED). The spore-film system was tested in various field campaigns performed in Germany and in Japan. The seasonal daily variation of UV radiation in Germany determined in the period November 1995 to December 1996 using the spore-film filter system in sunny conditions tallied well with model calculations. The daily dose in Germany measured with the spore-film system close to the summer solstice, in sunny conditions (20.45 MED), was approximately 20 times higher than the lowest value measured close to the winter solstice (0.82 MED), a result which was in accordance with model calculations. The data determined with the spore-film filter system in Sapporo and Naha, Japan, fitted to the erythema-weighted data calculated from spectroradiometric measurements (Brewer), even at low solar radiation angles in a solar spectrum with less UVB but significant UVA. The spore-film dosimeter values were about 103 +/- 8% of the integrated dose of the Brewer instrument. The standard deviation of the spore-film measurements obtained in Japan was 12.8%. The responsivity of the spore-film system towards longer wavelengths within the UVA spectrum was tested with the Okasaki Large Spectrograph with monochromatic radiation. At a wavelength of 365 nm--in a spectral region which is dominant in many tanning lamps and with minor importance for solar radiation in summer conditions--the tested spore-film system gave results that were close (112% compared to the calibration dose) to the calibration dose which was used for irradiation.

Bacillus subtilis

A simple method for simultaneous interphase-metaphase chromosome analysis in biodosimetry.

PURPOSE: To find a simple protocol for measuring chromosome damage both in G1 and in G2/M chromosomes, to overcome problems related to low mitotic index and cell-cycle alterations in biodosimetric tests. MATERIALS AND METHODS: The protocol is based on the use of calyculin A to induce premature chromosome condensation in human peripheral blood lymphocytes in different phases of the cell cycle. Chromosome exchanges were measured by fluorescence in situ hybridization (chromosomes 2 and 4) in lymphocytes from four different donors. Cells were exposed to 4Gy X-rays and the results were compared to aberrations in M phase (colcemid block) and G0 (premature chromosome condensation induced by fusion to mitotic hamster cells). RESULTS: Treatment with calyculin A produced a high fraction of chromosome condensation in different phases of the cell cycle. Cells in G1 and G2/M could be scored simultaneously for biodosimetry by chromosome painting. The condensation index was 5-20 times higher than the mitotic index (colcemid alone). The calyculin A treatment did not produce a significant increase in the background of chromosomal aberrations or modify the yield of chromosomal aberrations scored after exposure to X-rays. CONCLUSIONS: Induction of chromosome condensation by calyculin A is a powerful biodosimetric tool, which provides a high number of spreads for analysis and overcomes problems related to poor in vitro growth or cell-cycle alterations.

Cell Cycle

The relative biological effectiveness of accelerated carbon ions with different LET for inducing mitotic crossing over and intragenic reversion of the white-ivory allele in Drosophila larvae.

PURPOSE: To evaluate the relative biological effectiveness (RBE) of accelerated carbon ions generated with a synchrotron for inducing mutations as a function of linear energy transfer (LET), using the loss of heterozygosity for wing-hair mutations and the reversion of the mutant white-ivory eye-colour in Drosophila melanogaster. MATERIALS AND METHODS: The measurements were made using a combined mutation assay system so that induced mutant wing-hair clones as well as revertant eye-colour clones can be detected simultaneously in the same fly. Larvae were irradiated at the age of 72+/-6 h post-oviposition with X-rays or carbon ions with LET values of 13, 60 and 95 keV/microm. RESULTS: The RBE of carbon ions for producing wing-hair mosaic spots increased with increasing LET values. The RBE for the induction of eye-colour mutants did not change with LET. The estimated RBE values were found to be in the range 2 to 6.5 for the wing-hair and nearly unity for the eye-colour mosaic spot mutations. CONCLUSIONS: RBE-LET relationships were obtained for the induction of wing-hair and eye-colour mosaic spots. These relationships suggest that more complex types of DNA damage, such as nonrejoinable strand breaks that increase with LET, may be responsible for inducing the wing-hair mutation, while more simple forms of molecular damage induce reversion in the white-ivory allele.

Animals

The effect of track structure on the induction of chromosomal aberrations in murine cells.

PURPOSE: To measure chromosome aberrations in C3H 10T1/2 mouse fibroblasts using FISH painting at the first mitosis following exposure to 30 keV/microm hydrogen or neon ions. MATERIALS AND METHODS: Cells in plateau-phase were irradiated with 0.86 MeV protons at the TTT-3 Tandem accelerator in Naples (Italy), or with 400 MeV/n Ne ions at the HIMAC accelerator in Chiba (Japan). Colcemid-blocked cells were harvested at the first mitosis following exposure, and chromosome spreads were hybridized in situ with a fluorescein-labelled composite mouse DNA probe specific for chromosomes 2 and 8. RESULTS: Protons were more efficient than neon ions at the same LET in the induction of chromosome interchanges and breaks. Yields of complex exchanges were similar for both particles at the same dose, but protons produced mostly insertions, while with Ne exposure non-reciprocal exchanges were the most frequent complex-type exchange. CONCLUSIONS: Charged particles with the same LET produce different yields of chromosome aberrations, and some observed differences can be explained based on the available track-structure models.

Animals

Immunocytochemical localization of salivary peptide P-C in human submandibular gland.

Human saliva contains a proline-rich polypeptide, salivary peptide P-C, which potentiates insulin release and reduces glucagon release from perfused rat pancreas to decrease blood glucose level. To elucidate the process of secretion into humoral fluid of this peptide morphologically, we investigated ultrastructural localization of P-C in human submandibular gland by immunogold technique with anti-peptide P-C whose specificity to P-C was confirmed by immunoblotting. The labeling with gold particles which represents the distribution of P-C-like-immunoreactivity (P-C-LI) was detected in the secretory granules and rough endoplasmic reticula of the acinar serous cells and in few mucosa cells. P-C-LI was also observed in the lumen of striated duct but not intracellularly in the ductal cells themselves, indicating that P-C is not probably reabsorbed there. These results suggest that salivary peptide P-C is present in acinar serous cells, is secreted into the oral cavity, and may be reabsorbed through the digestive tract to modulate the blood glucose level after feeding.

Aged

Relative biological effectiveness of accelerated heavy ions for induction of morphological transformation in Syrian hamster embryo cells.

Syrian hamster embryo cells were used to study the morphological transformation induced by accelerated heavy ions with different linear energy transfer (LET) ranging from 13 to 400 keV/micron. Exponentially growing cells were irradiated with 12C or 28Si ion beams generated by the Heavy Ion Medical Accelerator in Chiba (HIMAC), then inoculated to culture dishes. Morphologically altered colonies were scored as transformants. Over the LET range examined, the frequency of transformation induced by the heavy ions increased sharply at very low doses no greater than 5 cGy. The relative biological effectiveness (RBE) of the heavy ions relative to X-rays first increased with LET, reached a maximum value of about 7 at 100 keV/micron, then decreased with the further increase of LET. Our findings confirmed that high LET heavy ions are much more effective than X-rays for the induction of in vitro cell transformation.

Animals

Inhibition in a microgravity environment of the recovery of Escherichia coli cells damaged by heavy ion beams during the NASDA ISS phase I program of NASA Shuttle/Mir mission no. 6.

We participated in a space experiment, part of the National Space Development Agency of Japan (NASDA) Phase I Space Radiation Environment Measurement Program, conducted during the National Aeronautics and Space Administration (NASA) Shuttle/Mir Mission No. 6 (S/MM-6) project. The aim of our study was to investigate the effects of microgravity on the DNA repair processes of living organisms in the in orbit. Heavy ion beam radiation- or ç-irradiation-damaged biological samples of Escherichia coli and the radioresistant bacterium Deinococcus radiodurans were prepared and placed in a biospecimen box, which was loaded into the RRMD III sensor unit of the Space Shuttle. Two identical sets of samples were left in the Spacehab's Payload Processing Facility (SPPF) in Florida, USA, as a control. (flight No. STS-84) was launched from NASA John F. Kennedy Space Center (KSC) in Florida, USA, on May 15, 1997. The mission duration was 9.22 days. An astronaut activated the biological samples in the biospecimen box in the Spacehab during orbit in order to start repair of the DNA damaged by heavy ion beams or ç-irradiation and the samples were incubated for 19 h 35 min at about 22ûC, the cabin temperature. The control specimens in the SPPF were subjected to the same treatment under terrestrial gravity. After returned to earth, we investigated cell recovery by comparing the repair of the radiation-damaged DNA of E. coli and D. radiodurans in the microgravity environment in space with that on Earth. The results indicated that the DNA repair process of E. coli, but not of D. radiodurans, cells was inhibited in a microgravity environment.

Cell Survival