Unwillingness to cooperate with COVID-19 contact tracing in Japan.

OBJECTIVES: Contact tracing for COVID-19 relies heavily on the cooperation of individuals with authorities to provide information of contact persons. However, few studies have clarified willingness to cooperate and motivation to provide information for contact tracing. This study sought to describe willingness to cooperate and motivation to report contact persons for COVID-19 contact tracing among citizens in Japan, and to assess any associated sociodemographic factors. STUDY DESIGN: Cross-sectional study. METHODS: This was an online-based survey using quota sampling. Participants were asked about their willingness to cooperate in reporting contacts for COVID-19 contact tracing if they tested positive. Participants also responded to questions regarding their reasons for cooperating or not cooperating and provided sociodemographic data. Multiple logistic regression analysis was performed to clarify associations between sociodemographic factors and willingness to cooperate. RESULTS: This study included 2844 participants. The proportion of participants who were not willing to cooperate in reporting contacts was 27.6%, with their main reasons being concerns about causing trouble for the other person and being criticised for revealing their names. Willingness to cooperate was lower among men, young adults and those with an educational level less than a university degree. CONCLUSIONS: To improve the effectiveness of contact tracing, educational campaigns, such as reducing the fear and stigma associated with COVID-19, may be important. Furthermore, it is essential to understand that individuals may have contacts whom they do not wish to disclose to others and to be considerate when handling such situations.

Resistance exercise enhances cognitive function in mouse.

Physical exercise has been shown to increase adult neurogenesis in the hippocampus and to enhance synaptic plasticity. It has been demonstrated that these neuroprotective effects can be observed following aerobic exercise. However, it remains unknown whether plasticity molecules, such as brain-derived neurotrophic factor (BDNF) and cyclic AMP response element-binding protein (CREB), are expressed in the hippocampus following resistance exercise. We applied voluntary progressive-resistance wheel exercise (RE) for 14 days, and measured BDNF and CREB in the hippocampus. The Morris water maze was also performed to estimate learning and memory. Furthermore, we measured RE effects on mammalian target of rapamycin (mTOR) and 70-kDa ribosomal protein S6 kinase (p70S6K) mediating muscle protein synthesis in the soleus. As a result, we found that RE enhanced cognition and elevated BDNF and CREB expressions in the hippocampus. Also, RE activated the mTOR-p70S6K signaling pathway in the soleus. We found that phosphorylated mTOR and p70S6K were significantly positively correlated with BDNF expression. Our results indicated that resistance exercise drove the protein synthesis signaling pathway in the soleus and enhanced hippocampal synaptic plasticity-related molecules. These results suggest the beneficial effects of resistance exercise on cognitive function.

Relation of the stages of change for exercise behaviors, self-efficacy, decisional-balance, and diet-related psycho-behavioral factors in young Japanese women.

BACKGROUND: A large proportion of young Japanese women is inactive. Exercise has important health benefits, however, abnormal weight/eating concerns and excessive dieting practices among physically active young women also have been reported in many cross-sectional studies. The purpose of this study was to examine the relationships between stages of change for exercise behaviors and exercise/dieting related psycho-behavioral factors using the Transtheoretical Model of behavior change as a theoretical framework. METHODS: A cross-sectional study included 450 young Japanese women aged 18 to 21 (18.4+/-0.67 years). Subjects in precontemplation (n=111, 24.7%), contemplation (n=120, 26.7%), preparation (n=177, 39.3%), action (n=17, 3.8%), and maintenance (n=25, 5.6%) were compared on physique, body composition, current exercise practices, exercise self-efficacy, decisional balance (benefits and costs exercise), as well as dieting behaviors and weight/eating concerns. RESULTS: Stages of change for exercise behaviors were significantly related to exercise self-efficacy and perceived benefits as well as to dieting behaviors and weight/eating concerns. Subjects in the higher stages had higher self-efficacy, perceived benefits of exercise, and healthy dieting behaviors; however, some of them also had unhealthier dietary practices, higher phobia of obesity and obsession with eating than those in lower stages. CONCLUSIONS: These findings provide support for applying the transtheoretical model of exercise behavioral change to Japanese young women. Additionally, it is also important to pay attention to stage specific psycho-behavioral factors related to their dieting.

A comparative pharmacodynamic study of the arrhythmogenicity of antidepressants, fluvoxamine and imipramine, in guinea pigs.

Among several classes of antidepressants, tricyclic antidepressants are known to prolong QTc intervals (QT interval corrected by heart rate) in electrocardiograms, while selective serotonin uptake inhibitors (SSRI) are considered to be devoid of arrhythmogenicity. In this study, we aimed to compare the arrhythmogenic potencies of imipramine (IMI), a typical tricyclic antidepressant, and fluvoxamine (FLV), an SSRI, at therapeutic and supratherapeutic concentrations using guinea pigs in vivo. Guinea pigs were anesthetized, and IMI (10 and 20 mg/kg/h) or FLV (20 mg/kg/h) was intravenously administered for 90 minutes to obtain the time-courses of drug concentrations in plasma and the changes in the QTc intervals during and after the drug administration. IMI induced distinct QTc prolongation in a dose-dependent manner, while FLV prolonged QTc intervals only slightly. A pharmacokinetic-pharmacodynamic analysis revealed that the potency for QTc prolongation of IMI was 1.7-fold higher than that of FLV. Taking the therapeutic concentration into account, the clinical risk of FLV for QTc prolongation was suggested to be 5-fold lower than that of IMI. Therefore, this SSRI agent was suggested to be safer than the tricyclic antidepressant for patients with cardiac risk factors, including arrhythmia, or for those taking other arrhythmogenic drugs concomitantly.

HUman MicroNucleus project: international database comparison for results with the cytokinesis-block micronucleus assay in human lymphocytes: I. Effect of laboratory protocol, scoring criteria, and host factors on the frequency of micronuclei.

Micronucleus (MN) expression in peripheral blood lymphocytes is well established as a standard method for monitoring chromosome damage in human populations. The first results of an analysis of pooled data from laboratories using the cytokinesis-block micronucleus (CBMN) assay and participating in the HUMN (HUman MicroNucleus project) international collaborative study are presented. The effects of laboratory protocol, scoring criteria, and host factors on baseline micronucleated binucleate cell (MNC) frequency are evaluated, and a reference range of "normal" values against which future studies may be compared is provided. Primary data from historical records were submitted by 25 laboratories distributed in 16 countries. This resulted in a database of nearly 7000 subjects. Potentially significant differences were present in the methods used by participating laboratories, such as in the type of culture medium, the concentration of cytochalasin-B, the percentage of fetal calf serum, and in the culture method. Differences in criteria for scoring micronuclei were also evident. The overall median MNC frequency in nonexposed (i.e., normal) subjects was 6.5 per thousand and the interquartile range was between 3 and 12 per thousand. An increase in MNC frequency with age was evident in all but two laboratories. The effect of gender, although not so evident in all databases, was also present, with females having a 19% higher level of MNC frequency (95% confidence interval: 14-24%). Statistical analyses were performed using random-effects models for correlated data. Our best model, which included exposure to genotoxic factors, host factors, methods, and scoring criteria, explained 75% of the total variance, with the largest contribution attributable to laboratory methods.

Effects of shift work on 24-hour ambulatory blood pressure and its variability among Japanese workers.

OBJECTIVES: This study examined the effects of rotating shift work on blood pressure in a comparison of ambulatory blood pressure and long-term changes in blood pressure between shift and day workers. METHODS: Ambulatory blood pressure was measured for 24-hour periods at an interval of 30 minutes for 27 shift workers and 26 day workers when they worked during the day. Blood pressure was compared between these 2 groups of workers for 4 time categories (awake, sleep, nonwork awake, and work periods). Their long-term blood pressures, recorded in annual surveys, were reviewed for long-term changes. These comparisons were adjusted for the effects of body mass index, alcohol intake, anger expression, and physical activity. RESULTS: On the average, sleep time was shorter and the anger-in (ie, anger suppressed) score was higher for the shift workers than for the day workers, but body mass index and alcohol intake did not differ between the 2 groups. Even after adjustment for these co-variables, the mean systolic blood pressure during the 24-hour, awake, and work periods were higher among the shift workers than among the day workers. The 24-hour standard deviations of the systolic blood pressures were also higher for the shift workers than for the day workers. Among the shift workers, but not among the day workers, a significant long-term increase was observed in systolic blood pressure measured in the annual surveys. CONCLUSIONS: These results suggest that shift work may increase systolic blood pressure levels among Japanese men.

The relationship between physical fitness and coronary risk factor profiles in Japanese women.

The purpose of this study was to investigate the relationship between physical fitness and coronary risk factor profiles in Japanese women. The subjects were 1,483 women (ages 30 to 69) who participated in a practical health promotion program. After medical examination, physical fitness was evaluated by conducting a symptom limited maximal exercise test by ergometer to measure maximum oxygen uptake (peakVO(2)) with an expired gas analyzer. The subjects were classified into 3 groups (high fitness, moderate fitness, and low fitness) according to age and physical fitness level. The results showed that the subjects in higher fitness groups had lower levels in: body mass index (BMI), percentage of body fat, waist-hip ratio, resting blood pressure, and atherogenic index, and higher HDL-cholesterol compared to those in lower fitness group. Even after adjustment for the effects of age and BMI, die subjects in the higher fitness groups had better coronary risk factor profiles. These results suggest that among Japanese women a high level of physical fitness is related to favorable coronary risk factor profiles.

Influence of serum micronutrients on the incidence of kinetochore-positive or -negative micronuclei in human peripheral blood lymphocytes.

The possible contribution of some selected serum micronutrients (beta-carotene, vitamins B12 and C, folic acid and alpha-tocopherol) to spontaneous chromosomal damage was investigated in human peripheral blood lymphocytes from 33 non-smoking healthy donors by the cytokinesis-block micronucleus assay. Labelling of micronuclei with antikinetochore serum was used to discriminate between kinetochore-positive and -negative micronuclei and thus between micronuclei which arise from whole chromosome loss and those which arise from chromosome breaks. Simple correlation analysis showed that age was significantly associated with the increased frequency of micronucleated cells, and this age-related increase in these cells was due to the increase in cells with both kinetochore-positive and -negative micronuclei. Serum micronutrient levels had no apparent significant effects on incidence of micronucleated cells except for the weak positive correlation between vitamin B12 levels and frequency of kinetochore-positive micronucleated cells. Multiple regression analysis with age and serum micronutrient levels as independent variables showed that (a) age was the most influential variable for the frequency of micronucleated cells, (b) the serum vitamin C level was associated with increased frequency of spontaneous micronucleated cells, and this increase was mainly due to the increase in cells with kinetochore-positive micronuclei, and (c) the serum folic acid level was significantly and negatively related to the frequencies of cells with both kinetochore-positive and -negative micronuclei. To avoid the predominant age-effect, we also performed separate multiple regression analysis with age-adjusted frequency of micronucleated cells as dependent variable. The results from this analysis again showed a significant and positive effect of serum vitamin C level on age-adjusted frequency of kinetochore-positive micronucleated cells, while marginal negative effect of folic acid on age-adjusted frequency of total micronucleated cells (P < 0.06) and kinetochore-positive micronucleated cells (P < 0.051) was detected. These results suggest that age and serum vitamin C are definitely variables for frequencies of spontaneous chromosome loss, and that serum folic acid is perhaps another important micronutrient which influence the frequency of spontaneous chromosomal damage.

Differences in HDL cholesterol concentrations in Japanese, American, and Australian children.

BACKGROUND: Mortality from coronary heart disease is relatively low in Japan compared with other developed countries and has remained low despite an increasing standard of living and an apparent increase in mean plasma cholesterol concentration in adults over the past three decades. Important differences in childhood plasma lipoprotein profile might contribute to some of the difference in coronary heart disease mortality seen between Japan and both Australia and North America. METHODS AND RESULTS: Plasma HDL cholesterol and total cholesterol were surveyed in representative populations of schoolchildren in Australia, Japan, and Bogalusa, La. The mean concentration of plasma HDL cholesterol (but not total cholesterol) was higher for Japanese schoolchildren than for Australian or US schoolchildren (P<.001). In addition, the difference in plasma HDL cholesterol between the ages of 8 to 10 years and 12 to 15 years was much greater for Australian (boys, 15.2%; girls, 2.6%) and US (boys, 9.1%; girls, 2.7%) children than for their Japanese counterparts (boys, 4.2%; girls, 1.9%). An examination of potential explanatory factors revealed little difference in body mass index between samples, higher physical activity levels for the Japanese compared with the Australians, and substantial differences in dietary intake between Japanese and Australian schoolchildren. CONCLUSIONS: The relatively high ratio of plasma HDL cholesterol to total cholesterol in Japanese schoolchildren and the relatively small negative difference of plasma HDL cholesterol with age may help to explain why the coronary heart disease mortality rate in Japan is low compared with that in other developed countries.

Interindividual variation in cytogenetic response to X-ray and colchicine measured with the cytokinesis-block micronucleus assay.

Interindividual variation in cytogenetic response to two different types of micronucleus (MN) inducer, X-rays (a clastogen) and colchicine (a spindle poison), was investigated in the peripheral blood lymphocytes of normal healthy donors by the cytokinesis-block MN method. The data for 124 donors between the ages of 19 and 80 years showed that the histogram of individual frequency of X-ray (2 Gy)-induced micronucleated cells followed the normal distribution (Shapiro Wilks W-test) with a significant interindividual variance (ANOVA, p < 0.001). This was, however, not the case for colchicine (0.03 microgram/ml)-induced micronucleated cells. Instead, a skewed distribution illustrating interindividual variation was evident (ANOVA, p < 0.001). Statistical analysis of the effect of age and sex on MN incidence by using the Kruskal-Wallis test indicated that age affected the baseline and colchicine-induced MN incidences strongly but not the X-ray-induced MN incidence. There was no effect of sex on the incidence of micronuclei induced by either agent. In order to avoid any possible effect of age on the MN index, data for young subjects aged less than 30 years old were analyzed separately. The results of this analysis again showed significant interindividual variations in baseline, X-ray-induced, and colchicine-induced micronucleated cell rates. Results of the correlation-coefficient analysis showed that neither X-ray-induced MN incidence nor colchicine-induced MN incidence was related to baseline MN incidence. No correlation between X-ray-induced and colchicine-induced MN incidences was also found by this analysis. These results suggest that interindividual variance in chromosomal response to mutagens in normal populations may be a real phenomenon, as is interindividual variance in baseline MN frequency, and that individual susceptibilities to the two different types of micronucleus inducers (X-ray and colchicine) are unrelated, and the baseline MN level is not of predictive value for the susceptibilities.

Relationships between exhaustive mood state and changes in stress hormones following an ultraendurance race.

To investigate how the pituitary-adrenal and sympathetic nervous hormones change in psychologically exhaustive states following an ultraendurance race, the Profile of Mood States (POMS), plasma ACTH, beta-endorphin, adrenaline, noradrenaline, and serum cortisol were measured in 29 male athletes two days before, immediately after, and one day after a triathlon. Psychological exhaustion was defined as possessing low POMS vigour and high fatigue immediately post-race. Eleven subjects met the criteria for the exhaustive group, and another ten were placed in the vigour group, which possessed high vigour regardless of fatigue score and the remaining eight subjects were excluded from analysis because they did not satisfy experimental protocol. Student's t-tests revealed no significant group differences in age, race time, pre-race POMS and hormone values. Immediately post-race, serum cortisol and plasma adrenaline did not differ between groups. However, significantly lower levels of plasma beta-endorphin (p = 0.03) and noradrenaline (p = 0.05), and relatively lower levels of plasma ACTH (P = 0.08) immediately post-race were observed in the exhaustive group when compared with the vigour group. We conclude that pituitary and sympathetic nervous hormone reactivity is attenuated following ultraendurance race in athletes showing psychological exhaustion and this is independent of race performance.

Inductions of oxidative DNA damage and mesothelioma by crocidolite, with special reference to the presence of iron inside and outside of asbestos fiber.

Inductions of oxidative DNA damage (oh8dG) in vitro and peritoneal mesothelioma in rats (F344, female) were compared between crocidolite (CR) and de-ironized crocidolite [DCR, washed by HCl and ethylenediamine tetraacetic acid (EDTA)] to verify the hypothesis that reactive oxygen species contribute to carcinogenesis, focusing on the role of iron present inside or outside of the CR. The yield of oh8dG was 14.6 oh8dG/10(5)dG in CR and 30.2 in DCR under simple incubation with DNA. In the incubation systems added several chemicals and H2O2, DCR induced higher levels of oh8dG than CR. Especially, the addition of Fe2O3 and H2O2 to DCR increased oh8dG in DNA depending on the Fe2O3 concentration, however, this tendency was not observed in the same system of CR. Surprisingly, 7 out of 10 rats died within 2 days after the injection of 10 mg of Fe2O3 following the DCR injection (5 mg/rat), showing necroses of hepatocytes from the surface of each lobe where CR and Fe2O3 particles had been deposited together. There was no death in other groups of rats. One year after the i.p. injection of CR (5 mg/rat, single injection), mesotheliomas were found in all rats administered DCR and Fe2O3 (2 mg/rat, once a week, for 35 weeks), in 4 rats of DCR alone (n = 10), in 5 rats of CR alone (n = 10) and in none of the rats administered Fe2O3 alone (n = 10). Therefore, present results indicate that the induction of oxidative DNA damage changed even when the same type of asbestos was washed by chemical treatment, and Fe2O3 promoted the development of mesothelioma which was induced by DCR.

Predominant induction of kinetochore-containing micronuclei by extracts of diesel exhaust particulates in cultured human lymphocytes.

The aneuploidy-inducing activity of extracts of diesel exhaust particulates from light duty (LD) and heavy duty (HD) engines was investigated in cultured peripheral blood lymphocytes of 8 healthy donors using the cytokinesis-block micronucleus test with the kinetochore labelling modification. A majority of the subjects tested showed a significant kinetochore-positive micronucleus induction after treatment with the highest dose (150 micrograms/ml) of LD extract, although some subjects also showed induction of kinetochore-negative micronuclei. Only one subject had significantly increased numbers of kinetochore-positive micronuclei at a dose of 400 micrograms/ml of HD extract. These results suggest that diesel extract, at least LD extract, possesses the ability to induce whole chromosome loss (aneuploidy) preferentially, although there are also chromosome breaks.

Micronucleus induction in cytokinesis-blocked mouse bone marrow cells in vitro following in vivo exposure to X-irradiation and cyclophosphamide.

A cytokinesis-block micronucleus (MN) method for the simultaneous but separate measurement of chromosome damage in erythroid and myeloid bone marrow cells is described. MN induction in cytokinesis-blocked mouse bone marrow cells in vitro following in vivo exposure to x-ray or cyclophosphamide (CP) was investigated. Immediately after whole body irradiation with acute doses of either 0, 1, 2 or 4 Gy x-rays, or 2 hr after treatment with either 0, 12.5, 25, or 50 mg CP/kg body weight, bone marrow cells were collected and then cultured in medium supplemented with 3.0 micrograms/ml cytochalasin B for 24 hr. The binucleated cells were scored in erythroid, myeloid, lymphoid and other cells. The myeloid/erythroid (M/E) ratio was decreased by x-irradiation or CP treatment in a dose-dependent manner. The dividing index (DI; binucleated cells/binucleated + mononucleated cells; %) was decreased in both erythroid and myeloid cells in the same manner. Dose-dependent increases in MN frequency were observed following x-irradiation in both erythroid and myeloid cells. A similar dose-dependent MN induction was observed with CP. The MN frequency in myeloid cells was much greater than in erythroid cells (about 4-fold following 4 Gy exposure, and more than 10-fold after 50 mg/kg CP). Lymphoid and other cells were not suitable for scoring DI and MN frequency because of insufficient numbers of binucleated cells. These results suggest that micronuclei can be identified in both myeloid and erythroid cells and that myeloid cells are more susceptible to x-ray or CP-induced chromosomal damage than erythroid cells as expressed by MN induction.

Optical multimode frequency-domain reflectometer.

A multimode laser can instantaneously generate a carrier frequency of significantly wide band. The proposed systems, composed of a free-running multimode laser diode, an optical spectrometer, and a computing system for fast Fourier transformation, can easily provide the potential for ultrahigh resolution of the order of 10 microm without scanning frequencies as in frequency-domain reflectometers of either the continuously or the stepwise-swept variety.

In vivo mutations at the H-2 locus in mouse lymphocytes.

An experimental system has been developed to study in vivo autosomal mutations in murine splenic lymphocytes. Mutant lymphocytes were isolated by immunocytotoxicity using monoclonal antibodies directed against the k and d alleles of the K and D H-2 histocompatibility loci and were enumerated using limiting-dilution cloning. Genomic allele loss in mutant clones was detected using allele-specific primers in a polymerase chain reaction. Mutant clones were classified on the basis of phenotypic and genotypic criteria into "no change", deletion or recombination mutants. The geometric mean mutation frequency in 102 mice was 2.42 x 10(-4). Detailed phenotypic and genotypic study of 87 mutant clones from 4 mice revealed "no change" mutants in 83%, mutants due to deletion in 7% and mutants due to recombination in 7%. Anomalous results were obtained in 3% of mutant clones. The development of an animal model for study of in vivo mutations at an autosomal locus will further advance study of mutations, particularly those involving chromosomal changes such as mitotic recombination.