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1.  Use of organic solvents in large research institutions in Japan 
Laboratories in research institutions use organic solvents in research and development. Nevertheless, the types of solvents in use have been seldom reported. This study was initiated to elucidate types of organic solvents used in large research institutions in Japan, with a focus on possible different use among research fields.
In 2010–2011, 4517 laboratories in seven large research institutions were visited. In accordance with legal stipulations, air in each laboratory was collected in polyvinyl fluoride bags and analyzed by direct injection into a gas-chromatograph for 47 types of organic solvents. In evaluation, the laboratories were grouped by 5 research fields, i.e., agriculture, biology, medicine, natural science, and technology and engineering.
Types of organic solvents commonly used in research activities were not diverse. Those commonly used were chloroform and 1,2-dichloroethane out of 7 Group 1 organic solvents (with high toxicities); 6 organic solvents, i.e., acetone and methyl alcohol in general, ethyl acetate, hexane and toluene in technology and engineering laboratories; and xylenes in medical fields out of 40 Group 2 organic solvents (with relatively low toxicities). Judging from solvent vapor concentrations, work environments in more than 99 % of laboratories were considered adequate. Nevertheless, use of chloroform in high-performance liquid chromatography (HPLC) resulted in inadequate environments in 30 laboratories (0.7 %).
Organic solvents commonly used were not very diverse. Work environments in research laboratories were generally good, but the environment with use of chloroform in HPLC analysis remained yet to be improved.
PMCID: PMC3773089  PMID: 23404090
Chloroform; Organic solvents; Research laboratory; Unmixed solvents; Xylenes
2.  Reference value and annual trend of white blood cell counts among adult Japanese population 
This study was initiated to establish the reference values (the 95 % lower limit in particular) for white blood cell (WBC) counts in peripheral blood of general Japanese population. Additional attempts were made to examine whether the reference range had changed in the past 100 years, and which factors had induced such change in WBC counts.
Data employed were WBC counts of >100 thousand apparently healthy Japanese men, collected in 2002 and in 2010, respectively. Information on smoking habits was collected simultaneously.
The distribution of WBC counts was essentially normal. Arithmetic mean (AM) WBC was 6,248 cells/mm3 in 2002 and 6,162 cells/mm3 in 2010. Based on the 2010 observation, 3 × 103 WBCs/mm3 (after rounding of the figure) was identified as the 95 % lower limit of the reference value for the population. No clear age dependency was detected. Smoking induced elevation in WBC, whereas WBC returned to the level of never smokers after quitting for 3 or more years.
Historical review disclosed a secular trend of decrease in WBC in the past 100 years, so that about 8 % of never-smoking men would be considered leukocytopenic according to the conventional cutoff of 4 × 103 cells/mm3 as a screening level. Decreased smoking rates and improved general hygiene are discussed as possible factors for WBC count reduction. Thus, WBC count of 3 × 103 cells/mm3 is recommended as the 95 % lower limit of the reference value for screening cases with reduced WBC counts.
PMCID: PMC3590320  PMID: 23054993
Annual trend; Japanese; Leukocyte counts; Men; Reference value; White blood cell counts
3.  Activities of occupational physicians for occupational health services in small-scale enterprises in Japan and in the Netherlands 
Occupational health service (OHS) for small-scale enterprises (SSEs) is still limited in many countries. Both Japan and the Netherlands have universal OHS systems for all employees. The objective of this survey was to examine the activities of occupational physicians (OPs) in the two countries for SSEs and to investigate their proposals for the improvement of service.
Questionnaires on types and sizes of the industries they serve, allocation of service hours (current and desired), sources of information for occupational health activities etc. were mailed in 2006 to 461 and 335 Japanese and Dutch OPs, respectively, who have served in small- and medium-scale enterprises. In practice, 107 Japanese (23%) and 106 Dutch physicians (32%) replied, respectively.
Results and Conclusions
Total service time per month was longer for OPs in the Netherlands than OPs in Japan. Japanese OPs spent more hours for health and safety meetings, worksite rounds, and prevention of overwork-induced ill health (14–16% each). Dutch OPs used much more hours for the guidance of absent workers (48%). Thus, service conditions were not the same for OPs in the two countries. Nevertheless, both groups of OPs unanimously considered that employers are the key persons for the improvement of OHS especially in SSEs and their education is important for better OHS. The conclusions should be taken as preliminary, however, due to study limitations including low response rates in both groups of physicians.
PMCID: PMC2836247  PMID: 20130904
Education; Employer; Occupational physician; Occupational health services; Small-scale enterprises

Results 1-3 (3)