Biomedical subjects

R Kanda

Publications and source records attributed to R Kanda.

At least 19 recordsLinked to original sources

PubMed2006

Investigation of new cytogenetic biomarkers specific to high-LET radiation using in vivo and in vitro exposed human lymphocytes.

PURPOSE: To find detectable cytogenetic biomarkers that can offer information about the radiation quality of in vivo exposure retrospectively. MATERIALS AND METHODS: Chromosome-type aberrations of peripheral lymphocytes of uterine cancer patients that received internal gamma- and external X-ray therapy or carbon beam therapy and of victims severely exposed to neutrons and gamma-rays in a criticality accident that occurred in Tokai-mura, Japan were analysed. Data obtained from in vitro irradiation experiments using 60Co gamma-rays and 10 MeV neutrons were compared with the in vivo exposure data. RESULTS: The ratio of acentric rings to dicentric chromosomes (termed RaD ratio) and that of excess fragments to dicentrics (termed EfD ratio) showed significant (p < 0.05) differences between the two groups of cancer patients, and these ratios for accidental victims were in between the values of the two groups of cancer patients. The in vitro studies using doses equivalent to 1 - 3 Gy of gamma-rays have confirmed that the EfD ratios were increased with the high LET (linear energy transfer) and RaD ratios decreased. CONCLUSION: The present data show that the RaD and EfD ratios can be used as cytogenetic biomarkers of exposure to high-LET radiation at least within a few years of exposure.

Aged↗

PubMed2004

Sister chromatid exchanges in ring chromosomes following X-irradiation of human lymphocytes.

PURPOSE: To examine whether X-rays induce sister chromatid exchanges (SCE). MATERIALS AND METHODS: Peripheral lymphocytes irradiated in vitro or in vivo were cultured and treated with okadaic acid to generate premature chromosome condensation (PCC). When identical spreads were analysed using conventional Giemsa staining and pan-centromeric fluorescence in situ hybridization painting, ring chromosomes were observed. RESULTS: In PCC preparations, cells in the late G(2) phase and late M phase were observed. In late M phase cells, 17-20% of ring chromosomes lacked one chromatid (single-chromatid ring), irrespective of dose. Both the distribution patterns of centromeres in rings and intercentromere distances in dicentric rings indicate that a considerable number of single-chromatid rings might be formed by SCE occurring in a chromosome-type ring, thereby joining strands of two rings, followed by a transformation into one ring. These single-chromatid rings were less stable in vivo than chromosome-type rings. CONCLUSION: Single-chromatid rings visualized clearly using PCC techniques indicate SCE in the respective rings. Contrary to the conventional SCE-detecting technique, this approach does not require the use of bromodeoxyuridine, which itself leads to SCE. Some of the observed SCE might be secondary products resulting from the repair of radiation-induced DNA damage, while others may be spontaneous.

Cell Cycle↗

PubMed2002

Dynamic analysis of chromosome aberrations in three victims of the Tokai-mura criticality accident.

PURPOSE: To investigate the dynamics of chromosome aberrations in the blood cells of three workers severely exposed to neutrons and gamma-rays in a criticality accident that occurred in Tokai-mura, Japan, in 1999. MATERIALS AND METHODS: The change with time of the frequency of' chromosome aberrations in the three patients was examined using a new analysis to score drug-induced prematurely condensed ring chromosomes (PCC-R) and a conventional meta-phase analysis. RESULTS: The frequencies and cellular distributions of PCC-R, dicentrics and rings did not change significantly among the samples obtained at 9-48h after the accident while the first depletion of lymphocytes occurred. The distributions of these aberrations in the cells of two patients showed a slight overdispersion compared with a Poisson distribution reflecting neutron and non-uniform exposures. The dose response curve of rings paralleled that of dicentrics, but not PCC-R. The half-lives of PCC-R (8.5 months) and of rings (8.7 months) were shorter than that of dicentrics (13.5 months). CONCLUSIONS: In the three patients of the Tokai-mura accident, lymphocytes in the circulating and extravascular pools had reached equilibrium at 9h, and highly damaged lymphocytes did not selectively move away from the circulatory system during the first rapid depletion of lymphocytes after exposure. Data on the in vivo half-life of PCC-R as well as dicentrics and rings obtained in the present study may be useful for retrospective dosimetry.

Adult↗

PubMed2001

Cytogenetical dose estimation for 3 severely exposed patients in the JCO criticality accident in Tokai-mura.

A dose estimation by chromosome analysis was performed on the 3 severely exposed patients in the Tokai-mura criticality accident. Drastically reduced lymphocyte counts suggested that the whole-body dose of radiation which they had been exposed to was unprecedentedly high. Because the number of lymphocytes in the white blood cells in two patients was very low, we could not culture and harvest cells by the conventional method. To collect the number of lymphocytes necessary for chromosome preparation, we processed blood samples by a modified method, called the high-yield chromosome preparation method. With this technique, we could culture and harvest cells, and then make air-dried chromosome slides. We applied a new dose-estimation method involving an artificially induced prematurely condensed ring chromosome, the PCC-ring method, to estimate an unusually high dose with a short time. The estimated doses by the PCC-ring method were in fairly good accordance with those by the conventional dicentric and ring chromosome (Dic+R) method. The biologically estimated dose was comparable with that estimated by a physical method. As far as we know, the estimated dose of the most severely exposed patient in the present study is the highest recorded among that chromosome analyses have been able to estimate in humans.

Chromosome Aberrations↗

PubMed2000

Improvement of accuracy of chromosome aberration analysis for biological radiation dosimetry.

The frequency of chromosome aberrations in circulating lymphocytes is accepted as being the most reliable indicator of the absorbed dose of radiation. Researches done to improve the accuracy of cytogenetic analysis are described in this review. These include investigations of in vitro factors that affect the yield of radiation-induced aberrations and of in vivo factors that affect the chromosomal radiosensitivity of individuals. Improved chromosome-painting methods for accurate judgment of dicentrics and translocations are introduced. The practicality of these advanced cytogenetic techniques is shown by examinations of individuals exposed in the radiation accident at Tokaimura in 1999.

Accidents, Occupational↗

PubMed1999

Allocyclic X chromosome visualized by drug-induced premature chromosome condensation.

Calyculin A, an inhibitor of serine/threonine protein phosphatases, can induce premature chromosome condensation (PCC) in human peripheral lymphocytes. In female lymphocytes treated with calyculin, one highly condensed chromosome per nucleus was frequently observed at early to middle S phase. When these PCC spreads were hybridized with a whole chromosome-painting probe for the X chromosome, one large spot and a cluster of small spots were observed in a cell. Judging from the Giemsa stained image, the former seemed to have finished DNA replication, while the latter was in the process of replication. Because this large spot was seldom observed in male PCC spreads, it was considered an inactive X chromosome. The inconsistency of this observation with earlier reports that the inactive X chromosome replicates later than autosomes and the active homolog is discussed.

Chromosome Painting↗

PubMed1999

Chemically induced premature chromosome condensation in human fibroblast cell lines: fundamental study for applications to the biodosimetry of local exposure.

The premature chromosome condensation (PCC) of human peripheral lymphocytes treated with inhibitors of protein phosphatase has been demonstrated to be an excellent tool for the estimation of high-dose whole-body exposure. To develop a new biodosimetry for local exposure, the cytogenetical reaction of human fibroblast lines to PCC inducers was examined and compared with that of lymphocytes. The efficiency of the induction by calyculin A was greater than that by okadaic acid in both cell types. Calyculin A induced PCC in 5-Gy-irradiated and unirradiated samples at almost the same frequency in the lymphocytes, whereas the efficacy was considerably lower in irradiated fibroblasts than in unirradiated ones. Calcium ionophore enhanced the induction of PCC in irradiated fibroblasts, although PCC frequencies were still much lower than those in the lymphocytes. The frequency of ring chromosomes observed in 2- and 5-Gy-irradiated fibroblasts was too low to be used as a marker for cytogenetic dosimetry, and that of excess fragments, scored as the observed chromosome number minus 46, might be substituted. The frequency of excess fragments for 2-, 5-, and 10-Gy-irradiated fibroblasts was less than 0.75, about 1 and a few per cell, respectively, although these values changed with the culture period. The prospects and limitations of the application of PCC techniques to fibroblasts are discussed.

Cell Cycle↗

PubMed1999

Phosphatase inhibitors and premature chromosome condensation in human peripheral lymphocytes at different cell-cycle phases.

The cytogenetical reaction of human peripheral lymphocytes to okadaic acid and calyculin A was examined. Calyculin A could induce PCC about 20 times more effectively than okadaic acid. Their mechanisms of PCC induction were judged similar by their dose-dependent manner and chromosome morphology. Contrary to earlier studies suggesting that chemicals could not induce PCC in G1 cells where little cyclin B is present, the present study showed that calyculin A could induce PCC in lymphocytes not only at S and G2/M but also at the second G1 phase after PHA stimulation in vitro. PCC was induced slightly in lymphocytes both at G0 and the first in vitro G1 phase even when the calyculin A concentration increased one hundred fold. It was found that calcium ionophore A23187 increased frequencies of G0-PCC induced by calyculin A, although a further refinement is necessary to obtain a suitable morphology of G0-PCC for cytogenetic studies.

Calcimycin↗

PubMed1999

Easy biodosimetry for high-dose radiation exposures using drug-induced, prematurely condensed chromosomes.

PURPOSE: To propose a practical method of biodosimetry for high-dose estimation. MATERIALS AND METHODS: Okadaic acid in the range 100 nM to 500 nM was given for 1-6 h to cultured lymphocytes that had been exposed in the range of 0 Gy to 40 Gy. The frequency of the cells with prematurely condensed chromosomes (PCC) was compared with that of metaphases accumulated by 0.05 microg/ml colcemid. The dose-response relationship of the yield of prematurely condensed ring chromosomes (PCC rings) in the irradiated lymphocytes was examined. RESULTS: The 0.05 microg/ml colcemid collected few metaphases when lymphocytes were irradiated to over 10 Gy. However, 500 nM okadaic acid produced a substantial number of analysable PCC in lymphocytes that had been exposed in the range of 0 Gy to 40 Gy. After 1 h of treatment, the 500 nM okadaic acid gave the most suitable chromosome morphology for the analysis. PCC rings were narrow, which facilitated their detection in Giemsa-stained preparations. The yield of PCC rings increased dose-dependently up to 20 Gy. CONCLUSION: PCC rings are a more suitable indicator than dicentrics at high doses over 10 Gy. This technique requires no particular equipment or exceptional skill. After a serious radiation accident, it can be easily performed in a short time in most medical facilities to obtain dose information to assist physicians.

Azure Stains↗

PubMed1999

Effect of estradiol on radiation-induced chromosome aberrations in human lymphocytes.

As a part of studies on physiological factors that affect radiosensitivity, we examined the in vitro effect of estradiol (E2) on the yield of radiation-induced chromosome aberrations in human peripheral lymphocytes. Lymphocytes were cultured for 3 days in the medium containing E2 at 0-100,000 ng/ml. On the second day, they were irradiated by X-rays at 3 Gy, and then 2% phytohemagglutinin and 0.05 microgram/ml colcemid were added to the medium. After further 48 h, mitotic indices and the yields of chromosome aberrations were examined at various E2 concentrations. E2 treatment at concentrations above 1000 ng/ml resulted in dose-related inhibition of mitosis. Repeated experiments showed that the yield of dicentrics plus centric rings in the culture containing E2 at 100 ng/ml was significantly higher than the yields at 0 ng/ml. Similarly, the yield of total chromosome breaks in the culture containing E2 at 100 ng/ml was significantly higher than that at 1 ng/ml. This study provides the direct evidence in human that radiosensitivity may vary in relation to hormonal conditions.

Chromosome Aberrations↗

PubMed1998

Visualization of clear echocardiographic images with near field noise reduction technique: experimental study and clinical experience.

BACKGROUND: With transthoracic echocardiography, it is sometimes difficult to obtain a clear image of the apical portion of the heart because of noise near the transducer. To reduce this artifact, we have developed a new technique (near field noise reduction, NFNR) based on the digital filtering by using radiofrequency signals. This technique may be useful for the accurate measurement of the wall thickness of the myocardium in the near field. The objectives of these studies were (1) to determine the accuracy of this new technique for the measurement of wall thickness in the experimental study and (2) to determine whether the improvement in the image quality in the apical portion can be obtained in the clinical setting by using the NFNR technique. EXPERIMENTAL STUDY: By using the NFNR technique, we measured wall thickness of three kinds of phantoms (wall thickness 9.0, 14.0, and 21.0 mm) moving at various velocities (5 to 80 mm/sec) in the water bath with artifact produced by a single probe. It was difficult to obtain clear echocardiographic images of the phantom and measure its wall thickness because of the artifact. By using the NFNR technique, on the other hand, the same phantom was clearly imaged. It was possible to measure the wall thickness of each phantom at each moving velocity with the NFNR technique. Mean differences between the echocardiographic measurement and actual value of wall thickness in each phantom model (9.0, 14.0, and 21.0 mm) were 0.04 +/- 0.58 mm, 0.09 +/- 0.58 mm, and -0.02 +/- 0.24 mm, respectively. CLINICAL STUDY: We studied 25 initial patients in whom the near field was not clearly imaged in apical views by conventional echocardiography because of near field noise. Apical four-chamber or two-chamber views were obtained with and without the NFNR technique. Two observers independently graded endocardial visualization for the 50 segments by using a three-point scale (0 = endocardium not seen, 1 = seen in part but not all of the segment, 2 = endocardium seen along entire segment). The mean segment score in the imaging with the NFNR technique was significantly higher than that without the NFNR technique (observer 1: 1.8 +/- 0.7 vs 1.2 +/- 0.8, p < 0.01; observer 2: 1.6 +/- 0.7 vs 1.2 +/- 0.8, p < 0.01). CONCLUSIONS: The newly developed NFNR technique provides clear echocardiographic images and accurate wall thickness measurement in the experimental model even when it is difficult to obtain clear images because of the artifact. This new technique will be useful in the reduction of near field noise in the clinical setting.

Echocardiography↗

PubMed1998

Non-fluorescent chromosome painting using the peroxidase/diaminobenzidine (DAB) reaction.

PURPOSE: To develop and validate non-fluorescent chromosome painting for bright-field microscopy using the peroxidase/diaminobenzidine (DAB) reaction. MATERIALS AND METHODS: Peripheral blood lymphocytes were taken from patients with uterine cancer who had received heavy-ion radiation therapy. Chromosome slides were treated with RNase and pepsin, denatured mildly, hybridized with a biotinylated DNA probe specific for whole-chromosome 4 and stained using the peroxidase/DAB reaction with an avidin-biotin amplification. The slides were analysed under a bright-field microscope and an atomic force microscope. The detection rate of chromosome aberrations by DAB painting was compared with that obtained by dual analysis of Giemsa staining and FISH painting. RESULTS: When chromosomes 4 were painted, 11.5% of unstable aberrations were detected by DAB painting, while 10.8% of them were found by dual analysis of Giemsa staining and FISH painting. CONCLUSION: A DAB painting method that can effectively detect rearranged aberrations was established. It has advantages over FISH painting: the preparations can be analysed by bright-field microscope, can be preserved permanently and are suitable for analysis by an automated system.

3,3'-Diaminobenzidine↗

PubMed1997

Pilomatricoma with a bullous appearance.

A 15-year-old Japanese girl had an asymptomatic nodule on the right thigh of seven months' duration. The clinical appearance was similar to that of a bulla. There was a history of blunt trauma from dog scratch to the skin over the tumor shortly before tumor growth. Histopathological findings were consistent with pilomatricoma. In the overlying dermis, the collagen bundles were compressed to the tissue surrounding the tumor and the large space was seen. Around the tumor, some dilated endothelium-lined vascular channels were found, which were identified as lymphatic vessels.

Adolescent↗

PubMed1996

Comparison of the yields of translocations and dicentrics measured using conventional Giemsa staining and chromosome painting.

Inconsistent results have been reported regarding the yields of translocations and dicentrics measured using chromosome painting. This inconsistency may be due to mis-scoring of dicentrics as translocations because painting is unsuited to identify centromere positions. In the present study, chromosome aberrations exclusively in the first mitosis after irradiation were analyzed using human peripheral lymphocytes. When identical metaphases were analyzed by both painting and conventional Giemsa staining, which is the most reliable method to locate centromeres, equal frequencies of translocations and dicentrics were observed.

Centromere↗

PubMed1994

Involvement of human papillomavirus type 20 in epidermodysplasia verruciformis skin carcinogenesis.

The involvement of human papillomavirus (HPV) in skin carcinogenesis in a patient with epidermodysplasia verruciformis was studied. This patient had disseminated pityriasis versicolor-like lesions, flat warts, and a malignant skin carcinoma. HPV types 3, 17, 20 (HPV-20), and 38 were isolated and molecularly cloned from the benign skin lesions of this patient. Of these HPVs, only HPV-20 was detected in the malignant skin carcinoma. Transcripts of HPV-20 were also expressed in the carcinoma. These findings suggest that HPV-20 was involved in the skin carcinogenesis in this patient.

Adult↗

PubMed1994

Effects of colcemid concentration on chromosome aberration analysis in human lymphocytes.

As a part of technical improvements of chromosome aberration analysis on human peripheral lymphocytes for biological radiation dosimetry, we examined the optimal conditions for the use of colcemid in chromosome preparation in order to obtain enough number of cells at metaphase in the first cell division. When treated with colcemid at concentrations below 0.01 microgram/ml from the beginning of culture, cultures harvested at 48 hours had low mitotic indices. Colcemid treatment at 0.025 to 0.05 microgram/ml during 48 hours resulted in high mitotic indices (8 to 15%) and almost of the mitotic cells remaining in the 1st cell division, suggesting that this range of colcemid concentration was appropriate for continuous treatment with colcemid. We further examined the effect of colcemid concentration on the quantitative consistency of the yields of radiation-induced chromosome aberration. Repeated experiments showed that the yield of dicentrics and centric rings in the culture having colcemid at 0.025 microgram/ml concentration were larger than that at 0.05 microgram/ml. These data indicate the importance of assuring the accuracy of colcemid concentration in the lymphocyte culture for cytogenetic radiation dosimetry.

Cells, Cultured↗

PubMed1990

Severe intractable common warts associated with human papillomavirus 2, 3 and 20.

A 26-year-old male had had numerous common warts on the feet and hands since childhood. They had repeatedly undergone etretinate cryosurgery, always responding well to it. However, the warts reappeared. Human papillomavirus (HPV) 2, 3 and 20 were detected in the warts using Southern's blot hybridization technique with HPV DNA. Histologically, the warts showed swollen, clear keratinocytes with vacuolated degeneration not found in common warts. The findings are presented in this paper.

Adult↗

PubMed1989

Types of human papillomavirus isolated from Japanese patients with epidermodysplasia verruciformis.

Virological studies were performed on 12 patients with epidermodysplasia verruciformis (EV). Three types of lesions were observed: red plaques, pityriasis versicolor (PV)-like macules and plane warts. Human papillomavirus (HPV) 14, 20 and 21 were isolated from the plaques, HPV 3, 14 and 38 from flat warts and HPV 5, 12, 17, 20 and 38 from PV-like lesions. No clear relationship could be established between the different lesions and the types of HPV. Types 17 and 20 have been isolated most frequently from Japanese EV patients and HPV 5, frequently detected in other countries, is less common, whereas HPV 8 has not been isolated. Skin cancers occurred in six of the cases (50%) and all had benign lesions that were PV-like. At least one type of HPV 5, 17 or 20 could be isolated from these benign lesions and HPV 17 or 20 detected in the cancers. These three types of HPV in EV patients appear to be involved in the malignant transformation.

Adult↗