A Survey of Semen Indices in InsecticideSprayers: Michihiro Kamijima, et al. Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine-This study aims at clarifying the semen indices of insecticide sprayers who are exposed mainly to organophosphorus and pyrethroid insecticides. Eighteen male sprayers out of 54 working for 9 companies in central Japan and 18 age-matched students or medical doctors as unexposed controls participated in detailed reproductive check-ups conducted in summer and the following winter. The sprayers were exposed to insecticides more in summer, the busiest season, than winter, the off-season (p<0.05). Erythrocyte true cholinesterase activities in the sprayers were lower than in the controls in summer (p<0.05), and decreased in significant association with the increase in exposure frequency. Testicular volumes in the sprayers tended to be smaller than in the controls (p=0.06). The serum testosterone concentration in winter in the sprayers was higher than in the controls (p<0.05), though luteinizing h o r m o n e a n d f o l l i c l e s t i m u l a t i n g h o r m o n e concentrations were not significantly different. The sperm counts and vitality were comparable between the groups, but detailed sperm motility analysis in summer revealed that the percentages of slow progressive and nonprogressive motile sperm were twice as high in the sprayers (p<0.05), and that of rapid progressive sperm tended to be lower (p=0.06). Such differences were not observed in winter. Differential sperm morphology counts showed that interaction of group and abstinence effects were significant in sperm Received Aug 19, 2003; Accepted Nov 28, 2003 Correspondence to: M. Kamijima, Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi 466-8550, Japan (e-mail: kamijima@med.nagoya-u.ac.jp) with normal morphology and with head deformity only in the summer check-up. Despite possible inherent differences between the groups, the above seasondependent differences suggested that the observed lower semen quality in the sprayers was associated with pesticide spraying work.
Ontogenetic changes in the relationship between resting rate of oxygen consumption and wet body mass were examined at 20" C with the sea bream Pagrus major ranging from 0,00020 g (weight just after hatching) to 270 g (weight at 530 days old). There was a triphasic relationship between oxygen consumption of an individual fish M (pl min-I) and body mass W(g). During a very early stage (weight 0-0002~0~00025 g), corresponding to the pre-larval stage and with the transitional period to the post-larval stage, there was no substantial change in body mass. The mass-specific metabolic rate M / W (pl g -' min I) showed no clear relationship to body mass as expressed by the equation M/W=4.86+ 1.47 D, where D is age in days. During the post-larval stage (weight 0~000314~005 g), M / W remained almost constant independent of body mass following the expression M= 12.5 Wwy. During the juvenile and later stages (weight 040-270 g). M/ Wdecreased with increasing body mass following theexpression M = 6.3 Won*' which is significantly different from the expression for the post-larval stage (P< 0.001). Ontogenetic changes in the metabolism-body mass relationship are discussed from the viewpoint of relative growth of organs with different metabolic activities.
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