Malignant cell transformation by the SV-40 DNA and phagocytic activity related to alteration of cell membranes

In vitro cell transformation of human embryo cells could be induced by the DNA purified from SV 40. The result shows clearly that cell transforms a part of viral DNA into the genome. In addition, for the purpose of clarifying th~ biological differences between the normal and transformants the alteration of cell membraneous structures of transformants (hamster and mouse fibroblasts) were observed from mechanism of phagocytosis. The iron colloid particles are taken up by normal diploid fibroblasts but not by the human and hamster transformants. This fact suggests a differ~nce in the molecular arrangement of the cell membranes between the normal and transformants. In the presence of histones, however, the transformants phagocytize the colloid particles very actively. The results show that cell membranes of transformants are altered in the molecular structure r~sponsible for the surface charge. In addition, there is no remarkable quantative differences of sialic acids on the cell surfaces of non-malignant and malignant transformants so that phagocytic activity might be correlated to the alteration of molecular composition of cell membrane itself rather than of cell surfaces, i. e, sialic acids.</p

Diarrhea and related personal characteristics among Japanese university students studying abroad in intermediate- and low-risk countries

Despite an increasing number of students studying abroad worldwide, evidence about health risks while they are abroad is limited. Diarrhea is considered the most common travelers' illness, which would also apply to students studying abroad. We examined diarrhea and related personal characteristics among Japanese students studying abroad. Japanese university students who participated in short-term study abroad programs between summer 2016 and spring 2018 were targeted (n = 825, 6-38 travel days). Based on a 2-week-risk of diarrhea (passing three or more loose or liquid stools per day) among travelers by country, the destination was separated into intermediate- and low-risk countries. After this stratification, the associations between personal characteristics and diarrhea during the first two weeks of their stay were evaluated using logistic regression models. Among participants in intermediate-risk countries, teenagers, males and those with overseas travel experience were associated with an elevated risk of diarrhea; the odds ratios (95% confidence intervals) were 2.42 (1.08-5.43) for teenagers (vs. twenties), 1.93 (1.08-3.45) for males (vs. females) and 2.37 (1.29-4.33) for those with overseas experience (vs. none). Even restricting an outcome to diarrhea during the first week did not change the results substantially. The same tendency was not observed for those in the low-risk countries. Teenage students, males and those with overseas travel experience should be cautious about diarrhea while studying abroad, specifically in intermediate-risk countries

Lack of Modifying Effects of Intratracheal Instillation of Quartz or Dextran Sulfate Sodium (DSS) in Drinking Water on Lung Tumor Development Initiated with 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in Female A/J Mice

The purpose of the present study was to investigate the effects of inflammation, induced by intratracheal instillation (i.t.) of quartz as an environmental factor in the lung or drinking of dextran sulfate sodium (DSS) as an environmental factor in the colon on lung tumors in female A/J mice initiated with NNK. For comparison, colonic preneoplastic lesions, aberrant crypt foci (ACF), were also assessed. A/J mice at 6 weeks of age were divided into 5 groups, and Groups 1, 2 and 3 were pretreated with NNK (2 mg / 0.1 ml saline / mouse, intraperitoneal injection) at week 0. For a week, 2% DSS in drinking water was administered to the mice in Groups 2 and 4 beginning in week 1. In week 2, the mice of Groups 3 and 5 were exposed to intratracheal instillation of quartz (0.1 mg/rat) suspended in 25 μl saline. The experiment was terminated after 16 weeks. The results for the lung tumors and colonic ACFs showed a lack of modifying effects of the inflammation in either site. Hematologically and histopathologically, the inflammation induced by 0.1 mg quartz in the lung and 2% DSS in the colon was lacking or only mild at the end of 16 weeks. These results suggest that there may be differences in sensitivity to inflammation that determine tumor promoting potential

An Intratracheal Instillation Bioassay System for Detection of Lung Toxicity Due to Fine Particles in F344 Rats

It is an urgent priority to establish in vivo bioassays for detection of hazards related to fine particles, which can be inhaled into deep lung tissue by humans. In order to establish an appropriate bioassay for detection of lung damage after particle inhalation, several experiments were performed in rats using quartz as a typical lung toxic particle. The results of pilot experiments suggest that Days 1 and 28 after intratracheal instillation of 2 mg of fine test particles in vehicle are most appropriate for detection of acute and subacute inflammatory changes, respectively. Furthermore, the BrdU incorporation on Day 1 and the iNOS level on Day 28 proved to be suitable end-point markers for this purpose. An examination of the toxicity of a series of particles was performed with the developed bioassay. Although some materials, including nanoparticles, demonstrated toxicity that was too strong for sensitive assessment, a ranking order could be clarified. The bioassay thus appears suitable for rapid hazard identification with a possible ranking of the toxicity of various particles at single concentrations

Lung Carcinogenic Bioassay of CuO and TiO2 Nanoparticles with Intratracheal Instillation Using F344 Male Rats

Toxicity assessment of nanoparticles, now widespread in our environment, is an important issue. We have focused attention on the carcinogenic potential of copper oxide (CuO) and titanium dioxide (TiO2). In experiment 1, a sequential pilot study, the effectiveness of a carcinogenic bioassay featuring intraperitoneal injection (i.p.) of 20 mg 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) or 0.1% N-bis(2-hydroxypropyl)nitrosamine (DHPN) in drinking water for 2 weeks was examined. Based on the results, DHPN, as the lung carcinogen, and evaluation at week 30 were selected as the most appropriate for our purposes in Experiment 1. In experiment 2, the carcinogenic bioassay was used to assess the carcinogenic potentials of instilled nanoparticles of CuO and TiO2. There were no significant intergroup differences in the lung neoplastic lesions induced by DHPN, although the neoplastic lesions induced by the nanoparticles in the CuO or TiO2 intratracheal instillation (i.t.) groups, demonstrated a tendency to increase compared with the microparticles administration. At the very least, the carcinogenic bioassay with DHPN proved useful for assessment of the modifying effects of instilled particles, and further assessment of the carcinogenic potential of nanoparticles appears warranted

Association of breast feeding with early childhood dental caries: Japanese population-based study

Objectives: We investigated the association between breastfeeding duration during the first half year of life and the risk of early childhood caries from the age of 30 to 66 months in Japan. Design: Observational study of a longitudinal survey. Setting: A secondary data analysis of the Japanese Longitudinal Survey of Babies in the 21st Century. Participants: 43 383 infants at the age of 6 months. Outcome measures Early childhood caries—defined as a child's visit to a dentist for treatment of dental caries during the past 12 months—was ascertained from the caregiver from the age of 30 months in the survey. We estimated the risk of dental caries each year according to duration of breast feeding using logistic regression analyses. We controlled for a set of biological factors (birth weight, sex, parity and maternal age at delivery) and socioeconomic factors (maternal educational attainment and smoking status, marital status at delivery, family income and region of birth and residence). Results: We found that infants who had been breast fed for at least 6 or 7 months, both exclusively and partially, were at elevated risk of dental caries at the age of 30 months compared with those who had been exclusively formula fed. Adjusted ORs were 1.78 (95% CI, (1.45 to 2.17)) for the exclusively breastfed group and 1.39 (1.14 to 1.70) for the partially breastfed group. However, the associations became attenuated through the follow-up period and were no longer statistically significant beyond the age of 42 months for the partially breastfed group and beyond the age of 54 months for the exclusively breastfed group. Conclusions: We found an association between breast feeding for at least 6 or 7 months and elevated risk of dental caries at age 30 months. However, the association became attenuated as children grew older

Predictors of vasovagal reactions during preoperative autologous blood donation: a single-institution analysis

Studies examining risk factors associated with vasovagal reactions (VVRs) during autologous blood donations, especially in younger subjects, have been limited. The aim of the present study was to define risk factors for VVRs during preoperative autologous blood donation in patients, including those younger than 18 years old. We retrospectively analyzed 4192 autologous, preoperative blood donations between 2007 and 2015 at Okayama University Hospital. Eighty-seven (2.08%) of the patients experienced VVRs. VVRs occurred approximately three times as often in patients 0-17 years old (16/320, 5.0%) than in patients 18 years and older (71/3872, 1.8%). In particular, VVRs occurred more frequently in those 10-13 years old, and decreased with older age (P = 0.006). In a univariate analysis, younger age, lower body mass index, lower systolic blood pressure, lower body weight, lower total blood volume, female gender, first-time collection, and higher heart rate were associated with a higher incidence of VVRs. In a multivariate analysis, lower systolic blood pressure (P < 0.001), higher heart rate (P = 0.007), and first-time collection (P = 0.015), remained independent predictors of VVRs. These results emphasize the need for careful attention during blood collection

Association of dietary fiber intake with subsequent fasting glucose levels and indicators of adiposity in school-age Japanese children

Abstract Objective: To evaluate the relationships of fiber intake with subsequent body mass index SD-score, waist-to-height ratio, and serum fasting glucose levels among school-age Japanese children. Design: A prospective study of school-age Japanese children. Participants were followed from 6–7 to 9–10 years of age (follow-up rate: 92.0%). Fiber intake was assessed using a validated food frequency questionnaire. Serum fasting glucose was measured by a hexokinase enzymatic method. Using a general linear model, the associations between dietary fiber intake at baseline and body mass index SD-score, waist-to-height ratio, and serum levels of fasting glucose at follow-up were evaluated after considering potential confounding factors. Setting: Public elementary schools in a city in Japan Participants: A total of 2,784 students. Results: The estimated means for fasting glucose at 9–10 years of age were 86.45, 85.68, 85.88, and 85.58 mg/dl in the lowest, second, third, and highest quartile of fiber intake at 6–7 years of age, respectively (p= 0.033, trend p= 0.018). Higher fiber intake at 6–7 years of age was associated with lower waist-to-height ratio at 9–10 years of age (trend p= 0.023). The change in fiber intake was inversely associated with concurrent change of body mass index SD-score (trend p= 0.044). Conclusion: These results suggest that dietary fiber intake may be potentially effective to limit excess weight gain and lower glucose levels during childhood

The Japanese space gravitational wave antenna; DECIGO

DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future Japanese space gravitational wave antenna. DECIGO is expected to open a new window of observation for gravitational wave astronomy especially between 0.1 Hz and 10 Hz, revealing various mysteries of the universe such as dark energy, formation mechanism of supermassive black holes, and inflation of the universe. The pre-conceptual design of DECIGO consists of three drag-free spacecraft, whose relative displacements are measured by a differential Fabry– Perot Michelson interferometer. We plan to launch two missions, DECIGO pathfinder and pre- DECIGO first and finally DECIGO in 2024