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Sperm assessment methods
Information
Synergistic effect of mixtures? A recent US study has found that several “weak environmental oestrogens” demonstrated a synergistic increase in their oestrogenic activity when tested in pairs-a response that “may have profound environmental implications”. Investigators assessed the activity of dieldrin, endosulfan, toxaphene or chlordane alone and in pairs using a yeast model engineered to contain the human oestrogen receptor. Combinations of two of these chemicals were 160-1600 times more potent at “switching on” the receptor than when tested alone. A fivefold synergistic effect was found for a mixture of two PCBs (Arnold et al., Science 1996, 272, 1489).
Long-term immune efrects from dioxin A battery of immunological tests has demonstrated (reportedly for the first time) reduced immunocompetence in the lymphocytes of individuals occupationally exposed a number of years earlier to high levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCD D or dioxin) and other polychlorinated dibenzo-p-dioxins. The 11 German workers who had been exposed for up to IO yr had, when examined 7-l 7 years after the last exposure, TCDD body burdens (pg/g blood fat) 1@200-fold higher than age-matched office workers. with possible clinical Five of the II workers presented manifestations of dioxin toxicity (Tonn et a/.. Encironmental Health Perspectires 1996, 104, 422).
Chlorinated water and pregnancy An Italian study has found some evidence of adverse effects in the offspring of mothers drinking water treated with chlorine dioxide or sodium hypochlorite. Births during 1988-1989) were examined from one hospital in each of two towns similar in socioeconomic and industrial characteristics, but with differing policies on drinking water treatment. Of 676 mothers in the survey, 277 were exposed to chlorine dioxide, 108 to sodium hypochlorite. 163 to both, and 128 to neither. An increased risk of producing a smaller baby was identified in the women drinking (any) chlorinated water, while neonatal jaundice was more prevalent in the
Section
IO23
offspring of those exposed
to water treated with chlorine dioxide (Kanitz et al., Enrironmental Health Perspectives 1996, 104, 516).
Water disinfection by-products and DNA damage in mice Administration of dibromoacetic acid (DBA) or bromochloroacetic acid (BCA) in the drinking water for 3 wk produced a dose-related increase in liver DNA damage in mice. The tested dose range was about 25 to 500 mg/kg body weight/day. Two other water disinfection by-products. trichloroacetic acid (TCA) and dichloroacetic acid (DCA). similarly administered for up to IO wk. did not produce significant levels of DNA damage (Parrish et al., To.uicologja 1996, 110, 103).
Euxyl K400 and sensitization A group of French dermatologists has drawn attention to increasing sensitization problems to a cosmetics biocide Euxyl K400, a mixture of phenoxyethanol and dibromodicyanobutane. Standard patch tests (48-hr covered contact) were conducted between 1988 and 1994 on 1217 patients with contact dermatitis. Allergic reactions to Euxyl K400 (tested at 2% in petrolatum) were recorded in 25 of the patients, from an incidence of about I% in 1990 up to an incidence in excess of 3% in 1994. In males this trend was even more obvious, from 0% in 1990 up to over 7% in 1994. One of the patients who responded very strongly to Euxyl K400 in a patch test gave no reaction to either of the components (Vigan et al., European Journal of Dermatolog!, 1996, 6, 175).
Sperm assessment methods Standard methods for the assessment of sperm motility. morphology and counts in the rat, rabbit and dog have been outlined by a US expert working group. The group was convened to address current differences in methodology and to develop common optimal procedures for assessing sperm parameters, and thus enhance interlaboratory comparisons (Seed et al., Reproductive Toricologj, 1996, 10, 237).
abstracts are taken from a section of the BIBRA Bulletin, a current-awareness journal compiled by the Information and Advisory Section at BIBRA International. This unique monthly digest of health and safety developments informs its readers of the toxicological issues that may affect product acceptability in chemical and nutritional areas, new and proposed regulatory activities and current thinking of future legislation, worldwide. The BZBRA Bulletin is available on subscription. Further information can be obtained from the Information and Advisory Section of BIBRA (tel. +44 (0)181-652 1000; fax +44 (0)181-661 7029). These
Synergistic effect of mixtures? A recent US study has found that several “weak environmental oestrogens” demonstrated a synergistic increase in their oestrogenic activity when tested in pairs-a response that “may have profound environmental implications”. Investigators assessed the activity of dieldrin, endosulfan, toxaphene or chlordane alone and in pairs using a yeast model engineered to contain the human oestrogen receptor. Combinations of two of these chemicals were 160-1600 times more potent at “switching on” the receptor than when tested alone. A fivefold synergistic effect was found for a mixture of two PCBs (Arnold et al., Science 1996, 272, 1489).
Long-term immune efrects from dioxin A battery of immunological tests has demonstrated (reportedly for the first time) reduced immunocompetence in the lymphocytes of individuals occupationally exposed a number of years earlier to high levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCD D or dioxin) and other polychlorinated dibenzo-p-dioxins. The 11 German workers who had been exposed for up to IO yr had, when examined 7-l 7 years after the last exposure, TCDD body burdens (pg/g blood fat) 1@200-fold higher than age-matched office workers. with possible clinical Five of the II workers presented manifestations of dioxin toxicity (Tonn et a/.. Encironmental Health Perspectires 1996, 104, 422).
Chlorinated water and pregnancy An Italian study has found some evidence of adverse effects in the offspring of mothers drinking water treated with chlorine dioxide or sodium hypochlorite. Births during 1988-1989) were examined from one hospital in each of two towns similar in socioeconomic and industrial characteristics, but with differing policies on drinking water treatment. Of 676 mothers in the survey, 277 were exposed to chlorine dioxide, 108 to sodium hypochlorite. 163 to both, and 128 to neither. An increased risk of producing a smaller baby was identified in the women drinking (any) chlorinated water, while neonatal jaundice was more prevalent in the
Section
IO23
offspring of those exposed
to water treated with chlorine dioxide (Kanitz et al., Enrironmental Health Perspectives 1996, 104, 516).
Water disinfection by-products and DNA damage in mice Administration of dibromoacetic acid (DBA) or bromochloroacetic acid (BCA) in the drinking water for 3 wk produced a dose-related increase in liver DNA damage in mice. The tested dose range was about 25 to 500 mg/kg body weight/day. Two other water disinfection by-products. trichloroacetic acid (TCA) and dichloroacetic acid (DCA). similarly administered for up to IO wk. did not produce significant levels of DNA damage (Parrish et al., To.uicologja 1996, 110, 103).
Euxyl K400 and sensitization A group of French dermatologists has drawn attention to increasing sensitization problems to a cosmetics biocide Euxyl K400, a mixture of phenoxyethanol and dibromodicyanobutane. Standard patch tests (48-hr covered contact) were conducted between 1988 and 1994 on 1217 patients with contact dermatitis. Allergic reactions to Euxyl K400 (tested at 2% in petrolatum) were recorded in 25 of the patients, from an incidence of about I% in 1990 up to an incidence in excess of 3% in 1994. In males this trend was even more obvious, from 0% in 1990 up to over 7% in 1994. One of the patients who responded very strongly to Euxyl K400 in a patch test gave no reaction to either of the components (Vigan et al., European Journal of Dermatolog!, 1996, 6, 175).
Sperm assessment methods Standard methods for the assessment of sperm motility. morphology and counts in the rat, rabbit and dog have been outlined by a US expert working group. The group was convened to address current differences in methodology and to develop common optimal procedures for assessing sperm parameters, and thus enhance interlaboratory comparisons (Seed et al., Reproductive Toricologj, 1996, 10, 237).
abstracts are taken from a section of the BIBRA Bulletin, a current-awareness journal compiled by the Information and Advisory Section at BIBRA International. This unique monthly digest of health and safety developments informs its readers of the toxicological issues that may affect product acceptability in chemical and nutritional areas, new and proposed regulatory activities and current thinking of future legislation, worldwide. The BZBRA Bulletin is available on subscription. Further information can be obtained from the Information and Advisory Section of BIBRA (tel. +44 (0)181-652 1000; fax +44 (0)181-661 7029). These