Some lessons on radiological protection learnt from the accident at the Fukushima Dai-ichi nuclear power plant

The accident at the Fukushima Dai-ichi nuclear power plant released a large quantity of radioactive iodine and caesium into the environment. In terms of radiological protection, the evacuation and food restrictions that were adopted in a timely manner by the authorities effectively reduced the dose received by people living in the affected area. Since late March, the transition from an emergency to an existing exposure situation has been in progress. In selecting the reference exposure levels in some areas under an existing exposure situation, the authorities tried to follow the situation-based approach recommended by the ICRP. However, a mixture of emergency and post-emergency approaches confused the people living in the contaminated areas because the reactor conditions continued to be not completely stable. In deriving the criteria in an existing exposure situation, the regulatory authority selected 20 mSv y(-1). The mothers in the affected area believed that a dose of 20 mSv y(-1) was unacceptably high for children since 1 mSv y(-1) is the dose limit for the public under normal conditions. Internet information accelerated concern about the internal exposure to children and the related health effects. From some experiences after the accident the following lessons could be learned. The selection of reference doses in existing exposure situations after an accident must be openly communicated with the public using a risk-informed approach. The detriment-adjusted nominal risk coefficient was misused for calculating the hypothetical number of cancer deaths by some non-radiation experts. It would not be possible to resolve this problem unless the ICRP addressed an alternative risk assessment to convey the meaning and associated uncertainty of the risk to an exposed population. A situation-based approach in addition to a risk-informed approach needs to be disseminated properly in order to select the level of protection that would be the best possible under the prevailing circumstances. A dialogue between radiation and other risk experts such as those dealing with chemical exposures is now needed.

Development of a web-based CT dose calculator: WAZA-ARI

A web-based computed tomography (CT) dose calculation system (WAZA-ARI) is being developed based on the modern techniques for the radiation transport simulation and for software implementation. Dose coefficients were calculated in a voxel-type Japanese adult male phantom (JM phantom), using the Particle and Heavy Ion Transport code System. In the Monte Carlo simulation, the phantom was irradiated with a 5-mm-thick, fan-shaped photon beam rotating in a plane normal to the body axis. The dose coefficients were integrated into the system, which runs as Java servlets within Apache Tomcat. Output of WAZA-ARI for GE LightSpeed 16 was compared with the dose values calculated similarly using MIRD and ICRP Adult Male phantoms. There are some differences due to the phantom configuration, demonstrating the significance of the dose calculation with appropriate phantoms. While the dose coefficients are currently available only for limited CT scanner models and scanning options, WAZA-ARI will be a useful tool in clinical practice when development is finalised.

Estimation of the number of CT procedures based on a nationwide survey in Japan

In 2007, a nationwide survey was conducted to determine the frequency of CT procedures in Japan in order to compare the current use of CT among developed countries. The frequency of adult and pediatric CT scans was estimated using a model based on the results of the survey. Survey questionnaires were sent to 2,266 CT facilities: 1,068 government hospitals and 1,198 other hospitals and non-hospital medical centers. The questionnaire requested information including the number of beds, outpatients per day, type of CT scanner, various body regions scanned, and the number of scans performed. The results of the study indicate that the number of CT procedures was closely correlated with the number of hospital beds. The authors estimate that approximately 20.5 million procedures were performed in 2005 and 21.2 million in 2006. The number of pediatric CT procedures was calculated by multiplying the total number of CT procedures by the estimated fraction of pediatric (0-15 y) CT procedures. Annual pediatric CT procedures were estimated to have been approximately 580,000 in 2005 and 600,000 in 2006. The present study indicates that the number of procedures per thousand of population, 166 for total CT and 32-34 for pediatric CT, is lower in Japan than in the U.S.

ICRP Publication 111 - Application of the Commission's recommendations to the protection of people living in long-term contaminated areas after a nuclear accident or a radiation emergency

In this report, the Commission provides guidance for the protection of people living in long-term contaminated areas resulting from either a nuclear accident or a radiation emergency. The report considers the effects of such events on the affected population. This includes the pathways of human exposure, the types of exposed populations, and the characteristics of exposures. Although the focus is on radiation protection considerations, the report also recognises the complexity of post-accident situations, which cannot be managed without addressing all the affected domains of daily life, i.e. environmental, health, economic, social, psychological, cultural, ethical, political, etc. The report explains how the 2007 Recommendations apply to this type of existing exposure situation, including consideration of the justification and optimisation of protection strategies, and the introduction and application of a reference level to drive the optimisation process. The report also considers practical aspects of the implementation of protection strategies, both by authorities and the affected population. It emphasises the effectiveness of directly involving the affected population and local professionals in the management of the situation, and the responsibility of authorities at both national and local levels to create the conditions and provide the means favouring the involvement and empowerment of the population. The role of radiation monitoring, health surveillance, and the management of contaminated foodstuffs and other commodities is described in this perspective. The Annex summarises past experience of longterm contaminated areas resulting from radiation emergencies and nuclear accidents, including radiological criteria followed in carrying out remediation measures.

Mechanisms of L-DOPA-induced cytotoxicity in rat adrenal pheochromocytoma cells: implication of oxidative stress-related kinases and cyclic AMP

L-DOPA therapy for Parkinson's disease has a double-edge effect on nigrostriatal dopaminergic neurons: L-DOPA increases the intracellular level of dopamine, but it induces neuron cytotoxicity in a concentration-dependent manner. To investigate the molecular signaling mechanisms that underlie the concentration-dependent effects of L-DOPA on cell viability, the activities of mitogen-activated protein kinases (MAPKs) and apoptotic enzymes were measured in rat adrenal pheochromocytoma (PC12) cells in the presence of a low concentration (20 muM) and high concentrations (100-200 muM) of L-DOPA. At the low concentration, L-DOPA was not cytotoxic and its presence increased the activities of extracellular signal-regulated kinase (ERK)1/2, p38 MAPK, BadSer112, Bcl-2, and caspase-12. At the high concentrations, L-DOPA was cytotoxic and stimulated the activities of ERK1/2, p38 MAPK, c-Jun N-terminal kinase (JNK)1/2, BadSer155, caspase-12 and caspase-3. The increased levels of ERK1/2 and BadSer155 in the presence of high concentrations of L-DOPA did not protect against L-DOPA-mediated cytotoxicity. In addition, the levels of L-type Ca(2+) channel-sensitive intracellular cyclic AMP (cAMP) and Ca(2+) were elevated in the presence of L-DOPA, and the increase in the levels of intracellular cAMP may also play a role in cellular viability, since cAMP levels and cytotoxicity increased in parallel with L-DOPA concentrations and the addition of forskolin in the medium increased cytotoxicity in a concentration-dependent manner. These results suggest that, at a low and non-toxic concentration, L-DOPA may promote cell survival by increasing the activities of ERK1/2, BadSer112 and Bcl-2, while, at high concentrations, L-DOPA activates the caspase-3 cell death enzyme through the JNK1/2 and p38 MAPK signaling pathways as well as endoplasmic reticulum stress that activates caspase-12. Intracellular cAMP levels may also play a role here. The results may lead to an effective therapy for Parkinson's disease.

Hedgehog Signaling Pathway Is a New Target of Cancer Stem Cell Therapy for Breast Cancer Patients

Introduction: Hedgehog (Hh) signaling pathway is crucial for growth and patterning during embryonic development. We have shown that Hh pathway is constitutively reactivated in human breast cancer (Kubo M et al. Cancer Res 2004). Recently, it has been proposed that only a small subset, termed cancer stem cells (CSCs), posseses tumorigenicity. And, several investigations suggest contributions of morphogenesis pathways including Hh pathway in the maintenance of CSCs. Purpose of this study is to reveal an essential role of Hh pathway in the maintenance of CSCs, and also to reveal a possibility of Hh pathway as a target of CSCs therapy for breast cancer patients.Materials and Methods: A human breast cancer cell line MCF-7 was used. In the present study, we estimated CD44+CD24-/low cells or side population (SP) cells as CSCs. Flow cytometric analysis and sorting were performed to detect and collect CSCs, respectively. To confirm the high tumorigenicity of CSCs, we used a MCF-7 cell xenograft mouse model in NOD/SCID mice. To assess the expression of Hh pathway-related molecules, real-time RT-PCR and fluorescent immunostaining were performed. For blockade of Hh pathway, a Hh inhibitor, cyclopamine, and small interference RNA (si-RNA) against Gli1, a trans-activator of the Hh pathway, were used. We also synthesized peptides with specific affinity for a transmembrane receptor Patched1 (Ptch1).Results: CD44+CD24-/low cells and SP cells in total MCF-7 cells were 10-25% and 1-4%, respectively and these two populations were overlapped with each other. These CSCs were highly tumorigenic, and resistant to anticancer drugs including taxanes.Hh pathway-related molecules such as Shh, a ligand of Hh pathway, and Gli1 were predominantly expressed in CSCs. Cyclopamine and Ptch1 affinitive peptides could suppress the tumorigenicity of CSCs in NOD/SCID mice xenograft transplantation model.Conclusions: Hh pathway at least partly contributes to the maintenance of CSCs in MCF-7 cells. Thus, Hh pathway may be a valuable therapeutic target for CSCs therapy for breast cancer patients.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1161.

Myocardial DNA strand breaks are detected in biopsy tissues from patients with dilated cardiomyopathy

BACKGROUND

Progressive damage of cardiomyocytes with interstitial and replacement fibrosis accompanied by less inflammatory cell infiltration is observed in patients with dilated cardiomyopathy (DCM), suggesting some other mechanisms rather than necrotic cell death.

HYPOTHESIS

The aim of this study was to assess the possible involvement of apoptotic process in the pathogenesis of DCM and myocarditis.

METHODS

Endomyocardial biopsy was performed in patients with DCM (n = 9), myocarditis (n = 4), or atypical chest pain syndrome (as controls; n = 5). The TUNEL method was used for in situ detection of oligonucleosomal DNA strand breaks.

RESULTS

The TUNEL-positive cells were observed in three of nine patients with DCM and in all four with myocarditis, but in none of the controls. The TUNEL-positive nuclei were observed exclusively in cardiomyocytes in DCM, whereas in myocarditis they were detected mainly in interstitial cells and in a few myocytes. In DCM, interstitial fibrosis was greater in the TUNEL-positive than in TUNEL-negative patients (p < 0.05). In either DCM or myocarditis, electron microscopic examination could not reveal morphologic features of apoptosis of cardiomyocytes.

CONCLUSION

The DNA strand breaks were detected in cardiomyocytes in patients with DCM and mainly in interstitial cells in myocarditis. It is possible that the DNA strand breaks can be involved in mechanisms of progressive loss of functional cardiac units in these myocardial diseases.

Effects of bezafibrate in patients with chronic hepatitis C virus infection: combination with interferon and ribavirin

An association of hepatitis C virus (HCV) with low-density lipoproteins (LDL) in serum of patients with chronic hepatitis C (CHC) has been suggested. We conducted a prospective study in CHC patients complicated with hyperlipidaemia, to examine whether bezafibrate, which is commonly used for treatment of hyperlipidaemia, reduces serum HCV-RNA titre and improves liver dysfunction. Fifteen patients received daily oral bezafibrate treatment (400 mg/day) for 8 weeks, and its effects on serum lipids, transaminases, HCV-RNA titres, and HCV-RNA titres bound to LDL were evaluated. Fifteen untreated patients with CHC and hyperlipidaemia were used as controls. The mean serum alanine aminotransferase levels and HCV-RNA titres significantly decreased at the end of bezafibrate therapy in the treated group (105 +/- 34 to 80 +/- 32 IU/L, P = 0.02 and 2.23 +/- 2.71 to 1.78 +/- 2.38 x 10(7) copies/mL, P < 0.01 respectively), but no changes were observed in the control group. Serum HCV-RNA titres bound to LDL, as quantified by immunoprecipitation using anti-LDL antibody, also decreased in all 15 treated patients [5.55 +/- 6.59 to 1.07 +/- 1.58 x 10(6) copies/ml, P < 0.01 (mean reduction rate was -78.5 +/- 17.0%)]. Sucrose density-gradient ultracentrifugation study revealed that HCV-RNA-decreased density fractions after the bezafibrate were identical to LDL-density fractions (1.015-1.062 g/mL). Eight CHC patients were treated with bezafibrate, interferon, and ribavirin triple therapy for 32 weeks, and four patients achieved sustained virological response to therapy. This pilot study provides further evidence of an association between HCV and LDL in serum and suggests the potential usefulness of bezafibrate as an anti-HCV reagent for the treatment of CHC patients.

Comparison of a digital flat-panel versus screen–film, photofluorography and storage-phosphor systems by detection of simulated lung adenocarcinoma lesions using hard copy images

The purpose of this study was to compare hard copy images from a flat-panel detector digital radiography system with conventional radiography, photofluorographic radiography and storage phosphor radiography for the detection of simulated lung adenocarcinoma lesions and also for radiation dose. To test the diagnostic performance of these four systems, the authors used 15 types of lung adenocarcinoma phantom according to Noguchi's classification and an anthropomorphic chest phantom. The visual evaluation of tumour detectability by four radiologists and two general thoracic surgeons was examined with a five-level confidence scale. Lung doses were measured with glass dosemeters for the chest radiology systems under the conditions used by each hospital and centre. Our results indicated that flat-panel detector digital radiography and storage phosphor radiography are not necessarily superior to conventional radiography and photofluorographic radiography for detecting lung adenocarcinomas when only hard copy images are used, and this suggests a need to carefully optimize chest radiography.

A single administration of interleukin-4 antagonistic mutant DNA inhibits allergic airway inflammation in a mouse model of asthma

Interleukin 4 (IL-4) is essential for the switching of B cells to IgE antibody production and for the maturation of T helper (Th) cells toward the Th2 phenotype. These mechanisms are thought to play a crucial role in the pathogenesis of the allergic airway inflammation observed in asthma. In the present study, we examined the anti-inflammatory effects of DNA administration of murine IL-4 mutant Q116D/Y119D (IL-4 double mutant, IL-4DM), which binds to the IL-4 receptor alpha and is an antagonist for IL-4. Immunization of BALB/c mice with alum-adsorbed ovalbumin (OVA) followed by aspiration with aerosolized OVA resulted in the development of allergic airway inflammation. A single administration of IL-4DM DNA before the aerosolized OVA challenge protected the mice from the subsequent induction of allergic airway inflammation. Serum IgE level and extent of eosinophil infiltration in bronchoalveolar lavage (BAL) from IL-4DM DNA-administered mice were significantly lower than those in BAL from control plasmid-immunized mice. In our study, IL-4 or IL-4 mutants were not detected in sera from mice that had received a single administration of IL-4DM DNA. The results of this study provide evidence for the potential utility of IL-4 mutant antagonist DNA inoculation as an approach to gene therapy for asthma.

Sex differences due to dehydroepiandrosterone (DHEA) feeding affecting dehydroepiandrosterone sulfate secretion in golden Syrian hamsters

The metabolism of orally administered dehydroepiandrosterone (DHEA) by male and female golden Syrian hamsters was examined by quantification of DHEA and dehydroepiandrosterone sulfate (DHEAS) in gallbladder bile, urine and feces using high-performance liquid chromatography (HPLC). Plasma levels of DHEA and DHEAS were also determined by radioimmunoassay (RIA). After 5 days of oral DHEA administration (100 mg/kg body weight twice a day), RIA showed that plasma levels of DHEA and DHEAS were increased approximately 3-6 and 4-5 times, respectively, compared to controls. More than 95 % of circulating DHEA (S) in the peripheral blood was DHEAS. There was no significant sex difference in DHEAS plasma levels between male and female animals in the DHEA-supplemented group. However, 0.2 - 0.3 % of ingested DHEA was conjugated to DHEAS and excreted in urine by females, whereas less than 0.002 % was excreted in urine by males (p < 0.005). DHEAS was excreted in bile by males after DHEA supplementation, and the sex differences in DHEAS levels observed in bile were statistically significant (male, 18.7 +/- 7.5 vs. female, 5.6 +/- 3.1 micromol/l) (p < 0.005). Small amounts of ingested DHEA were excreted in an unchanged state in feces, and no sex difference was observed. These results suggest that there is a considerable sex difference in the conjugation and excretion of orally administered DHEA in the hamster.

Neonatal doses from X ray examinations by birth weight in a neonatal intensive care unit

The aim of this study was to investigate the frequency and type of X ray examinations performed on neonates classified according to their birth weight in a neonatal intensive care unit (NICU). In this study, the radiology records of 2408 neonates who were admitted to the NICU of Oita Prefectural Hospital between January 1994 and September 1999 were investigated. This study revealed that the neonates with earlier gestational ages and lower birth weights required longer NICU stays and more frequent X ray examinations made using a mobile X ray unit. The average number of X ray examinations performed on neonates of less than 750 g birth weight was 26 films per neonate. In regard to computed tomography and fluoroscopy, no significant relationship was found between the birth weight and number of X rays. This study revealed that the entrance-surface dose per neonate was dependent upon the birth weight, while the maximum dose was not dependent upon the birth weight. The average neonatal dose in the NICU was predominantly from computed tomography and fluoroscopy. The individual dose varied widely among neonates.

Radiation doses to neonates during X ray computed tomography examinations

As the survival rate of newborns has increased, the number of X ray computed tomography (CT) examinations performed on neonates has been increasing. The exposure doses from CT examinations are known to be higher than those from conventional radiography. Although radiation sensitivity of neonates is higher than that of adults, there are few reports on dose estimates of neonates in CT examinations. Four cylindrical phantoms and one neonatal phantom have been developed to estimate doses to neonates during CT examinations. Using these phantoms and glass dosemeters, absorbed doses were measured. Estimated exposure doses to neonates were higher than those to adults, and our results suggest a need to optimise carefully CT examinations in newborns.

Biomechanical implications of uphill training on the aetiology of tendinitis

It has been reported that a small decrease in the strain in the superficial digital flexor tendon (SDFT) occurs if the toe is raised during walking. Although walking on a slope appears similar to raising the toe, it is unclear whether uphill exercise decreases the strain in the SDFT. Because the force or strain on tendons is one of the important factors leading to tendon stress injury, we hypothesised that reducing the force in the SDFT during exercise may prevent tendinitis. The purpose of this study was to determine the effects of treadmill inclination on the force in the SDFT in the walking horse. 'Arthroscopically implantable force probes' (AIFP) were implanted into the SDFT of the forelimb of 4 horses. The AIFP output was recorded during walking on a treadmill inclined at 0%, 3%, 8% and then 0% again. When the inclination increased from 0 to 8%, the first peak of force in the SDFT decreased significantly, the second increased significantly, but the maximal force and the area under the force-time curve did not change. In conclusion, uphill walking on an inclined treadmill did not decrease the maximal force in the SDFT or the area under the force-time curve, however, the patterns of force were altered. Future research should focus on the force distributions of tendons and ligaments at faster gaits, because the effects of a change in hoof angle and slope may be greater at faster gaits.

Early glycemic control reduces large-for-gestational-age infants in 250 Japanese gestational diabetes pregnancies

Our objective was to test if tight glycemic control versus loose glycemic control in gestational diabetic patients and a gestational age of < 32 weeks influence fetal growth, fetal distress, and neonatal complication. We performed a retrospective study with 250 gestational diabetes mellitus in Japanese women. Two groups were categorized according to the timing at which good maternal glycemic control was attained at < 32 weeks and kept so until delivery (group 1) and > 32 weeks or never until delivery (group 2). In these two groups, neonatal growth (large-for-gestational age: LGA; appropriate- : AGA; and small- : SGA), neonatal complications (hypoglycemia, jaundice, polycythemia, and cumulative incidence), and incidence of fetal distress were compared. The chi2 test, unpaired t test, one-way analysis of variance (ANOVA) and multiple logistic regression analyses were used for statistical analyses. Maternal age, height, prepregnancy body mass index (BMI), gestational age at delivery were not different between the groups. In group 2 (> 32 weeks), LGA, macrosomia (> 4 kg), neonatal hypoglycemia was significantly increased compared with those in group 1. Incidence of SGA, fetal distress, and neonatal jaundice were not different between the groups. Multiple logistic regression analysis for LGA showed significant relation to timing of maternal glycemic control. We concluded that good glycemic control should be attained at < 32 weeks and maintained until delivery to reduce LGA infants and neonatal hypoglycemia in gestational diabetes mellitus. This management did not appear to decrease SGA infants or fetal distress.

Mycoplasma pneumoniae in children with pneumonia at Mbagathi District Hospital, Nairobi

OBJECTIVE

To determine the prevalence of mycoplasma pneumoniae in nasopharyngeal aspirates of children under five years of age suffering from pneumonia.

DESIGN

Cross-sectional survey.

METHODS

Two primer sets targeting the genes coding for adhesion protein and 16S rRNA were used in PCR and M. pneumoniae specific antibodies were detected using commercial article agglutination kit. Microbiological investigations to isolate common acute respiratory infectious pathogens were also carried out.

RESULTS

M. pneumoniae was detected in nasopharyngeal aspirates of 33.7% of the cases by PCR while serology was positive in only 4.1%. M. pneumoniae alone (single detection) was detected in 25% of the cases while 75% occurred with other acute respiratory infectious (ARI) pathogens. However, the results did not correlate with clinical outcome or the severity of pneumonia. No significant aetiology was found in 28% of the cases investigated, however microbiological investigations by culture revealed the presence of other aetiological agents as follows: Streptococcus pneumoniae (26%), Klebsiella pneumoniae (1%), Staphylococcus aureus (3%), E. coli (2%), parainfluenza viruses (5%), Salmonella(1%), adenovirus (4%), RSV (22%) and Candida spp(13%), Mycoplasma pneumoniae was more prevalent in children aged between six months and three years. Cases of M. pneumoniae PCR positive and S. pneumoniae exhibited similar seasonal distribution with peaks in May and September. However, there was no relationship between M. pneumoniae PCR positive and the severity of pneumonia.

CONCLUSION

More investigation is required to establish the significance of atypical pathogens in respiratory infections in Kenya.

A chemiluminescence reaction between hydrogen peroxide and acetonitrile and its applications

Here we report a new chemiluminescence reaction between basic aqueous H2O2 and acetonitrile. Its ultraweak chemiluminescence could be greatly enhanced by luminol, isoluminol-labeled streptavidin, and an Edman-type fluorescent reagent. Light emission was intense and long-lived, and this facilitated the initiation of the reaction and the measurement of the light emission. The present results permit us to propose a series of convenient, highly sensitive, and enzyme-free techniques for the detection and quantification of luminol, related conjugates, acetonitrile, and amino acids. Overall, this new chemiluminescence reaction will be quite promising for numerous applications in immunoassay, DNA hybridization, environmental monitoring. and postcolumn chromatographic detection.

[Effects of smoking on pulmonary function: a cross-sectional and longitudinal study]

Cross-sectional and longitudinal studies were done to investigate the influence that a change in smoking habit can have on the pulmonary function. Seventeen hundred and thirty nine people (698 men, 1,041 women), 39 years of age or older, from the population of a farming village located in the central part of Miyazaki Prefecture were examined. A population-based cohort study with a 4-time observation was done over an interval of 12 years. Forced vital capacity (FVC) and forced expiratory volume in one second (FEV1.0) were used as the index of respiratory function, and adjusted annual change of FVC and adjusted annual change of FEV1.0 were used as a pulmonary function inspection index. There was a statistical significance in both %FVC and %FEV1.0 to the predicted values between smokers and non-smokers at the beginning of observation. The adjusted annual change of FVC both of male- and female-smokers and the adjusted annual change of FEV1.0 of male-smokers was higher than those of non-smokers in the longitudinal study. Percent FVC, %FEV1.0 and the adjusted FEV1.0 change of former male-smokers were lower than those of continuing smokers. In addition to %FVC and %FEV1.0, annual change of FVC and annual change of FEV1.0 were important predictors of pulmonary function related to cigarette smoking.

Multidrug resistant Mycobacterium leprae from patients with leprosy

Sequences of the folP1, rpoB, and gyrA genes were analyzed for 88 isolates of Mycobacterium leprae from leprosy patients in Japan, Haiti, Indonesia, Pakistan, and the Philippines. Thirteen isolates (14.8%) showed representative mutations in more than two genes, suggesting the emergence of multidrug-resistant M. leprae.