Individual response of humans to ionising radiation: governing factors and importance for radiological protection.

Tissue reactions and stochastic effects after exposure to ionising radiation are variable between individuals but the factors and mechanisms governing individual responses are not well understood. Individual responses can be measured at different levels of biological organization and using different endpoints following varying doses of radiation, including: cancers, non-cancer diseases and mortality in the whole organism; normal tissue reactions after exposures; and, cellular endpoints such as chromosomal damage and molecular alterations. There is no doubt that many factors influence the responses of people to radiation to different degrees. In addition to the obvious general factors of radiation quality, dose, dose rate and the tissue (sub)volume irradiated, recognized and potential determining factors include age, sex, life style (e.g., smoking, diet, possibly body mass index), environmental factors, genetics and epigenetics, stochastic distribution of cellular events, and systemic comorbidities such as diabetes or viral infections. Genetic factors are commonly thought to be a substantial contributor to individual response to radiation. Apart from a small number of rare monogenic diseases such as ataxia telangiectasia, the inheritance of an abnormally responsive phenotype among a population of healthy individuals does not follow a classical Mendelian inheritance pattern. Rather it is considered to be a multi-factorial, complex trait.

Population panmixia and demographic expansion of a highly piscivorous marine fish Scomberomorus niphonius.

Population structure and demographic history of the Japanese Spanish mackerel Scomberomorus niphonius a highly piscivorous and migratory marine fish, were assessed using mitochondrial DNA control region sequences (n = 720) and microsatellite genotypes at five loci (n = 1331) for samples collected on Japanese coasts from 2001 to 2010. The population structure was panmictic and the haplotype and allele frequencies were temporally stable even during the recent recovery process. Demographic expansion was strongly supported throughout the Pleistocene, suggesting that the oscillating glacial and interglacial climate conditions in the Pleistocene had no substantial impact on the demographic history of S. niphonius.

Genetic effects of hatchery fish on wild populations in red sea bream Pagrus major (Perciformes, Sparidae) inferred from a partial sequence of mitochondrial DNA.

Variation in the mitochondrial DNA transcriptional control region sequence was investigated in wild and hatchery-released red sea bream Pagrus major from Kagoshima Bay, where an extensive hatchery-release programme has been conducted for >30 years. The programme has successfully augmented commercial catches in the bay (released juveniles have been produced from the captive broodstock, repeatedly used over multiple generations). Samples were also obtained from outside the bay, where limited stocking has occurred. Genetic diversity indices measured as number of haplotypes, haplotype richness, haplotype diversity and nucleotide diversity were lower in hatchery-released fish than in wild fish. Genetic differences in wild fish from the bay, especially in the inner bay, compared with fish from outside the bay were detected in terms of decreased genetic diversity indices and changed haplotype frequencies. Unbiased population pair-wise F(ST) estimates based on an empirical Bayesian method, however, revealed low genetic differentiation between samples from the bay and its vicinity. Mixed stock identification analyses estimated the proportion of hatchery-released fish in wild populations in the inner and central bays at 39·0 and 8·7%, respectively, although the precision of the estimates was very low because of the small genetic differentiation between populations and relatively small sample sizes. Hence, the long-term extensive hatchery release programme has affected the genetic diversity of wild populations in the bay; however, the genetic effects were low and appeared to remain within the bay.

[Solitary capillary hemangioma in the lung: report of a case].

We report a case of pulmonary solitary capillary hemangioma of 59-year-old woman who visited our hospital for an abnormal chest shadow. She had no symptoms, but a computed tomography (CT) revealed a small irregular nodule at the periphery of right S9. Early lung cancer was suspected. Video-assisted thoracic surgery (VATS) was performed for the difinitive diagnosis and treatment in January, 2008. Macroscopically, the nodule showed ill defined margin and irregular in shape. Partial resection of the lung was performed and the histopathological diagnosis was solitary capillary hemangioma. Postoperative course was uneventful and there is no signs of recurrence.

Post-operative oral contraceptive use reduces the risk of ovarian endometrioma recurrence after laparoscopic excision.

BACKGROUND: The aim of this study was to evaluate the impact of post-operative oral contraceptives (OCs) use on the rate of recurrence after laparoscopic excision of ovarian endometrioma. METHODS: In May 2005, we introduced a 'post-operative OC recommendation' for patients treated with laparoscopic excision of endometrioma. That is, at the time of the operation, we provided each patient with information about OC, known and possible benefits and risks and let her decide whether to take OC. A retrospective cohort study included 87 patients who underwent a laparoscopy after May 2005. The endometrioma recurrence rate at 24 months was compared between those who used OC for the entire follow-up period OC (n = 34) and all of the others (n = 53). We also performed logistic regression analysis to identify variables associated with recurrence. A before-after study included another 224 patients who underwent a laparoscopy before May 2005 and compared the recurrence rate before and after introduction of the 'post-operative OC recommendation'. RESULTS: The recurrence rate in those who used OC for the entire period was significantly lower than in the 'others' group (2.9 versus 35.8%, relative risk 0.082, 95% CI 0.012-0.58, P < 0.001). Post-operative OC was determined as an independent variable associated with lower recurrence (OR 0.054, 95% CI 0.007-0.429, P < 0.001). The overall recurrence rate in patients who underwent laparoscopy after the introduction of the 'post-operative OC recommendation' was significantly lower than that in patients who received laparoscopy before the introduction (18.6 versus 33.1%, relative risk 0.56, 95% CI 0.32-0.97, P < 0.05). CONCLUSIONS: Post-operative OC use reduces the risk of ovarian endometrioma recurrence after laparoscopic excision. This information will help in appropriate planning of pre- and post-operative management.

Clonally expanded T lymphocytes from atomic bomb survivors in vitro show no evidence of cytogenetic instability.

Abstract Genomic instability has been suggested as a mechanism by which exposure to ionizing radiation can lead to cancer in exposed humans. However, the data from human cells needed to support or refute this idea are limited. In our previous study on clonal lymphocyte populations carrying stable-type aberrations derived from A-bomb survivors, we found no increase in the frequency of sporadic additional aberrations among the clonal cell populations compared with the spontaneous frequency in vivo. That work has been extended by using multicolor FISH (mFISH) to quantify the various kinds of chromosome aberrations known to be indicative of genomic instability in cloned T lymphocytes after they were expanded in culture for 25 population doublings. The blood T cells used were obtained from each of two high-dose-exposed survivors (>1 Gy) and two control subjects, and a total of 66 clonal populations (36 from exposed and 30 from control individuals) were established. For each clone, 100 metaphases were examined. In the case of exposed lymphocytes, a total of 39 additional de novo stable, exchange-type aberrations [translocation (t) + derivative chromosome (der)] were found among 3600 cells (1.1%); the corresponding value in the control group was 0.6% (17/3000). Although the ratio (39/3600) obtained from the exposed cases was greater than that of the controls (17/3000), the difference was not statistically significant (P = 0.101). A similar lack of statistical difference was found for the total of all structural chromosome alterations including t, der, dicentrics, duplications, deletions and fragments (P = 0.142). Thus there was no clear evidence suggesting the presence of chromosome instabilities among the clonally expanded lymphocytes in vitro from A-bomb survivors.

CAPABILITIES OF THE ARADOS-WG03 REGIONAL NETWORK FOR LARGE-SCALE RADIOLOGICAL AND NUCLEAR EMERGENCY SITUATIONS IN ASIA.

In 2015, the Asian Radiation Dosimetry Group established a regional network of biological dosimetry laboratories known as the ARADOS-WG03 (Working Group 03; Biological Dosimetry). A survey was conducted in 2017 to evaluate the capabilities and capacities of the participating laboratories for emergency preparedness and responses in large-scale nuclear and/or radiological incidents. The results of this survey were identified and assessed. The data provide important information on the current state of emergency cytogenetic biological dosimetry capabilities in the Asian region.

Cerebellar ataxia in a patient receiving calcineurin inhibitors after living donor liver transplantation: a case report.

Neurological complications of calcineurin inhibitors are frequent problems after transplantation. Cerebellar ataxia with other neurological findings and an abnormal density area in the subcortical white matter are found by MRI in the brains of most patients with central nervous system complications caused by calcineurin inhibitors. Such neurological complications are not life-threatening, but have a negative impact on the quality of life. We describe a 58-year-old woman who developed cerebellar ataxia at 4 days after living donor liver transplantation. She walked with a swaying gait, and after walking for 5 minutes she was unable to stand. Her symptoms persisted after a change from tacrolimus to cyclosporine, but dose reduction of cyclosporine and addition of mycophenolate mofetil cured the ataxia. We diagnosed a case of cerebellar ataxia without leukoencephalopathy or other neurological symptoms, as a new complication of calcineurin inhibitor treatment. We concluded that careful attention should be paid to neurological complications of calcineurin inhibitors.

Irradiation at Different Fetal Stages Results in Different Translocation Frequencies in Adult Mouse Thyroid Cells.

While it is generally believed that fetuses are at high risk of developing cancers, including leukemia, after low doses of radiation, it has been reported that atomic bomb survivors exposed in utero did not show a dose response for translocations in blood T lymphocytes when they were examined at approximately 40 years of age. Subsequent mouse studies confirmed that animals irradiated during the fetal stage did not show evidence of radiation effects in lymphocytes and bone marrow cells when they were examined after reaching adulthood. However, in a study of rat mammary epithelial cells, radiation effects were clearly observed after fetal irradiation. These results indicate that the fate of chromosome aberrations induced in a fetus could vary among different tissues. Here we report on translocation frequencies in mouse thyroid cells, which were irradiated at different stages of fetal development. Cytogenetic examination was conducted using fluorescence n situ hybridization (FISH) painting of chromosomes 1 and 3. Adult mice, 2 Gy X-ray irradiated at 15.5-day-old fetuses (E15.5), showed a higher translocation frequency (30/1,155 or 25.3 × 10-3) than nonirradiated adult controls (0/1,007 or 0.1 × 10-3), and was near that experienced by irradiated mothers and non-pregnant adult females (43/1,244 or 33.7 × 10-3). These results are consistent with those seen in rat mammary cells. However, when fetuses were irradiated at an earlier stage of development (E6.5) before thyroid organogenesis, the resulting observed translocation frequency was much lower (3/502 or 5.8 × 10-3) than that in E15.5 mice. These results suggest that after fetal irradiation, tissue stem cells record radiation effects primarily when the exposure occurs in cells that have been integrated into tissue. Embryonic stem cells that have been damaged prior to integration into the niche may undergo negative selection due to apoptosis, mitotic death or stem cell-niche cell interactions. The implications of these results in interpreting cancer risks after fetal irradiation are also discussed.

Clonally expanded T-cell populations in atomic bomb survivors do not show excess levels of chromosome instability.

Radiation-induced genomic instability has been studied primarily in cultured cells, while in vivo studies have been limited. One major obstacle for in vivo studies is the lack of reliable biomarkers that are capable of distinguishing genetic alterations induced by delayed radiation effects from those that are induced immediately after a radiation exposure. Here we describe a method to estimate cytogenetic instability in vivo using chromosomally marked clonal T-cell populations in atomic bomb survivors. The basic idea is that clonal translocations are derived from single progenitor cells that acquired an aberration, most likely after a radiation exposure, and then multiplied extensively in vivo, resulting in a large number of progeny cells that eventually comprise several percent of the total lymphocyte population. Therefore, if chromosome instability began to operate soon after a radiation exposure, an elevated frequency of additional but solitary chromosome aberrations in clonal cell populations would be expected. In the present study, six additional translocations were found among 936 clonal cells examined with the G-band method (0.6%); the corresponding value with multicolor FISH analysis was 1.2% (4/333). Since these frequencies were no higher than 1.2% (219/17,878 cells), the mean translocation frequency observed in control subjects using the G-band method, it is concluded that chromosome instabilities that could give rise to an increased frequency of persisting, exchange-type aberrations were not commonly generated by radiation exposure.

Diverse regulations of albumin gene expression by hepatocyte growth factor in HepG2 human hepatoma cells and primary culture of rat hepatocytes.

The effects of HGF on albumin gene expression in HepG2 human hepatoma cells and rat hepatocytes were investigated. HGF reduced the levels of albumin mRNA in HepG2 cells but the level was augmented in rat hepatocytes. By the transfection assay, HGF stimulated albumin promoter activity but repressed alpha-fetoprotein (AFP) enhancer activity regulating both AFP and albumin promoters in HepG2 cells. In contrast, HGF stimulated albumin promoter and AFP enhancer activities in rat hepatocytes. These results suggest that HGF elicits diverse responses of albumin gene expression in HepG2 cells and rat hepatocytes through the different biological actions on AFP enhancer in these cells.

Detection of hepatitis B virus X-region DNA in liver tissue from patients with hepatitis C virus-associated cirrhosis who subsequently developed hepatocellular carcinoma.

The risk of hepatocellular carcinoma (HCC) in patients chronically infected by hepatitis C virus (HCV) is relatively higher in Japan than in Western countries. The presence of hepatitis B virus X (HBX)-DNA in the liver tissue samples obtained on enrollment from 69 patients with HCV-associated cirrhosis who were subsequently followed in our hospital was analyzed by polymerase chain reaction (PCR). During the follow-up period of 5.7+/-3.2 years (mean +/- SD), 52 (75%) of 69 patients developed HCC. The PCR analysis indicated that the HBX-DNA sequence was detected in 25 (48%) of 52 patients who developed HCC during follow-up, but in only 3 (18%) of 17 patients who did not (P<0.05). These results suggest that HBX, a hepatitis B viral product relevant to hepatocarcinogenesis, is involved in development of HCC in some patients chronically infected by HCV in Japan.

Expression of alpha-calcitonin gene-related peptide in the enteric nervous system of rat small intestine.

We first detected alpha-calcitonin gene-related peptide (alpha-CGRP) precursor mRNA in the enteric nervous system (ENS) of rat small intestine by reverse transcriptase polymerase chain reaction (RT-PCR). The nucleotide sequence of the RT-PCR product was completely identical to that found in other organs. By in situ hybridization using digoxygenin-labeled alpha-CGRP precursor cRNA probe, we found that antisense probes detected a signal on nerve cell bodies of both submucosal and myenteric plexuses. Our findings indicate that the rat ENS participates in synthesis of alpha-CGRP precursor.

Phaeophytins from a cell suspension culture of the liverwort Plagiochila ovalifolia.

A suspension culture of the liverwort Plagiochila ovalifolia was established from callus tissue induced by culturing spores. From the cultured cells, four phaeophytins were isolated as major components and their structures determined by spectroscopic methods. The phaeophytin derivatives showed antibacterial activity. A major sesquiterpenoid, ovalifoliene, found in the mother plant, was detected in the cultures by GC-mass spectrometry.

Autopsy case of colocalized tumors of hepatocellular carcinoma and malignant lymphoma.

We present a rare case of colocalized tumors of hepatocellular carcinoma (HCC) and malignant lymphoma in the liver and bone marrow. A 64-year-old man with hepatitis B virus (HBV)-induced cirrhosis was admitted after detection of elevated serum alpha-fetoprotein level. He was diagnosed as having HCC and treated with chemotherapy and radiotherapy, but the size of the tumors did not diminish. After 11 months' hospitalization, he died due to rupture of esophageal varices. Autopsy revealed two heterogenic malignant tumors, HCC and malignant lymphoma (B cell type), in the liver. These tumors showed colocalization in the liver and bone marrow. The carcinogenetic process of colocalized tumors of HCC and lymphoma was not clarified, but the possibility that persistent HBV infection play a role in promoting hepatocarcinogenic and hematopoietic tumor growths in the reticuloendothelial organs could not be excluded.

Spontaneous loss of hepatitis B surface antigen in chronic carriers, based on a long-term follow-up study in Goto Islands, Japan.

Annual mass examination was performed between 1972 and 1997 in Tomie-town, Goto Islands, Japan, where hepatitis B virus (HBV) infection is very prevalent. In the present study, the incidence of spontaneous loss of hepatitis B surface antigen (HBsAg) in HBsAg carriers was determined in this area. Three thousand and nineteen inhabitants were tested for HBsAg two or more times in our annual surveys. Among them, 131 (4.3%) were defined as chronic HBsAg carriers based on the persistence of HBsAg for 1 or more years. These 131 subjects were followed for 12.2 +/- 7.6 years. During the follow-up period, spontaneous loss of HBsAg occurred in 38 (29%) of the 131 carriers, with a yearly incidence of 2.5%. This loss was seen more frequently in carriers aged 40 years or more on enrollment than in those aged less than 40 years during the same observation periods (P = 0.0141), irrespective of sex or the results of liver function tests. The values for liver function test results were similar before and after loss of HBsAg in these carriers. Stored serum samples were available for later analysis of HBV-DNA by polymerase chain reaction in 32 carriers with loss of HBsAg. The HBV-DNA sequence was detected in 26 (81%) and 2 of the 32 carriers (6%) before and after loss of HBsAg, respectively. These results indicate that spontaneous loss of HBsAg, largely attributable to clearance of viremia, occurs age-dependently in chronic carriers.

Refractory hepatic hydrothorax treated with transjugular intrahepatic portosystemic shunt.

A 66-year-old cirrhotic woman was referred to our hospital for evaluation of refractory pleural effusion and dyspnea. Massive right sided-pleural effusion but no ascites was detected. She had been treated with diuretics and albumin, repeated thoracenteses, and pleural drainage with an intercostal catheter, all of which had failed to relieve her symptoms. The diagnosis of hepatic hydrothorax without ascites was made by injection of technetium-99m-sulfur colloid into the peritoneal cavity. A transjugular intrahepatic portosystemic shunt was placed and successfully reduced the pleural effusion, resulting in complete relief of her symptoms. The patient has been free of symptoms for 18 months after the procedure.

The sympathetic nervous system promotes carbon tetrachloride-induced liver cirrhosis in rats by suppressing apoptosis and enhancing the growth kinetics of regenerating hepatocytes.

Norepinephrine is considered to possess potent anti-apoptotic action in regenerating hepatocytes. To clarify the role of the sympathetic nervous system in apoptosis that occurs in chronic liver damage and following the promotion of liver cirrhosis, we studied a carbon tetrachloride (CCl4)-induced liver injury model, using spontaneously hypertensive rats (SHR), Wistar-Kyoto rats (WKY), and chemically sympathectomized WKY. At 24 h after CCl4 administration. acute damage, characterized by vacuolated hepatocytes in the centrilobular zone, was greater in SHR than in WKY. This vacuolated change in WKY hepatocytes was significantly reduced by chemical sympathectomy with 6-hydroxydopamine (6-OHDA). After 48 h, the acute damage was dramatically improved in each animal, without significant differences between the three groups. In chronic damage after weekly repetition of CCl4 treatment for 4 weeks, fibrosis was evident in SHR, while in the other groups there was only scant fibrosis in the centrilobular zone. After 8 weeks' repetition of CCl4, liver cirrhosis was seen only in SHR. The incidence of apoptotic cells in areas of both acute and chronic damage in WKY, detected by terminal deoxynucleotidyl transferase-dUTP nick end labeling, was significantly increased in comparison with that in SHR, and was further increased by 6-OHDA pretreatment. In contrast, there was significantly greater enhancement of the growth of hepatocytes in SHR than in WKY in both acute and chronic damage. Moreover. hepatocyte growth kinetics in WKY was significantly inhibited after sympathectomy in acute injury, as evidenced by immunohistochemistry for proliferating cell nuclear antigen (PCNA). In vitro, the amount of hepatocellular apoptosis induced by transforming growth factor-beta1 was significantly decreased by incubation with norepinephrine. These findings suggest that the anti-apoptotic effect of the sympathetic nervous system increases cell growth kinetics and promotes liver cirrhosis in this animal model.

A biological method for the quantitative measurement of tetrodotoxin (TTX): tissue culture bioassay in combination with a water-soluble tetrazolium salt.

A tissue culture bioassay, using the mouse neuroblastoma cell line (Neuro2A), was improved to provide a simple and sensitive bioassay for TTX or sodium channel-blocking toxins (SCB). The water-soluble tetrazolium salt, 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetraz olium, monosodium salt (WST-1), was applied to replace the time-consuming and subjective cell-counting procedure of the cells with automatic measurement, using a microplate reader. It was also confirmed that this method is directly applicable to bacterial culture supernatants, with the precaution of possible interference.