Environmental contaminants such as persistent organic pollutants （POPs） are man-made bioaccumulative compounds with long half-lives that are found throughout the world as a result of heavy use in a variety of consum...Environmental contaminants such as persistent organic pollutants （POPs） are man-made bioaccumulative compounds with long half-lives that are found throughout the world as a result of heavy use in a variety of consumer products during the twentieth century. Wildlife and animal studies have long suggested adverse effects of exposure to these compounds on human reproductive health, which, according to the endocrine disrupter hypothesis, are ascribed to the compounds＇ potential to interfere with endocrine signaling, especially when exposure occurs during certain phases of fetal and childhood development. An extensive number of epidemiological studies have addressed the possible effects of exposure to POPs on male reproductive health, but the results are conflicting. Thus far, most studies have focused on investigating exposure and the different reproductive health outcomes during adulthood. Some studies have addressed the potential harmful effects of fetal exposure with respect to malformations at birth and/ or reproductive development, whereas only a few studies have been able to evaluate whether intrauterine exposure to POPs has long-term consequences for male reproductive health with measurable effects on semen quality markers and reproductive hormone levels in adulthood. Humans are not exposed to a single compound at a time, but rather, to a variety of different substances with potential divergent hormonal effects. Hence, how to best analyze epidemiological data on combined exposures remains a significant challenge. This review on POPs will focus on current knowledge regarding the potential effects of exposure to POPs during fetal and childhood life and during adulthood on male reproductive health, including a critical revision of the endocrine disruption hypothesis, a comment on pubertal development as part of reproductive development and a comment on how to account for combined exposures in epidemiological research.展开更多
The aim of the present study was to compare assessments of sperm concentration and sperm motility analysed by conventional semen analysis with those obtained by computer-assisted semen analysis （CASA） （Copenhagen R...The aim of the present study was to compare assessments of sperm concentration and sperm motility analysed by conventional semen analysis with those obtained by computer-assisted semen analysis （CASA） （Copenhagen Rigshospitalet Image House Sperm Motility Analysis System （CRISMAS） 4.6 software） using semen samples from 166 young Danish men. The CRISMAS software identifies sperm concentration and classifies spermatozoa into three motility categories. To enable comparison of the two methods, the four motility stages obtained by conventional semen analysis were, based on their velocity classifications, divided into three stages, comparable to the three CRISMAS motility categories： rapidly progressive （A）, slowly progressive （B） and non-progressive （C＋ D）. Differences between the two methods were large for all investigated parameters （P〈0.001）. CRISMAS overestimated sperm concentration and the proportion of rapidly progressive spermatozoa and, consequently, underestimated the percentages of slowly progressive and non-progressive spermatozoa, compared to the conventional method. To investigate whether results drifted according to time of semen analysis, results were pooled into quarters according to date of semen analysis. CRISMAS motility results appeared more stable over time compared to the conventional analysis; however, neither method showed any trends. Apparently, CRISMAS CASA results and results from the conventional method were not comparable with respect to sperm concentration and motility analysis. This needs to be accounted for in clinics using this software and in studies of determinants of these semen characteristics.展开更多
文摘Environmental contaminants such as persistent organic pollutants （POPs） are man-made bioaccumulative compounds with long half-lives that are found throughout the world as a result of heavy use in a variety of consumer products during the twentieth century. Wildlife and animal studies have long suggested adverse effects of exposure to these compounds on human reproductive health, which, according to the endocrine disrupter hypothesis, are ascribed to the compounds＇ potential to interfere with endocrine signaling, especially when exposure occurs during certain phases of fetal and childhood development. An extensive number of epidemiological studies have addressed the possible effects of exposure to POPs on male reproductive health, but the results are conflicting. Thus far, most studies have focused on investigating exposure and the different reproductive health outcomes during adulthood. Some studies have addressed the potential harmful effects of fetal exposure with respect to malformations at birth and/ or reproductive development, whereas only a few studies have been able to evaluate whether intrauterine exposure to POPs has long-term consequences for male reproductive health with measurable effects on semen quality markers and reproductive hormone levels in adulthood. Humans are not exposed to a single compound at a time, but rather, to a variety of different substances with potential divergent hormonal effects. Hence, how to best analyze epidemiological data on combined exposures remains a significant challenge. This review on POPs will focus on current knowledge regarding the potential effects of exposure to POPs during fetal and childhood life and during adulthood on male reproductive health, including a critical revision of the endocrine disruption hypothesis, a comment on pubertal development as part of reproductive development and a comment on how to account for combined exposures in epidemiological research.
文摘The aim of the present study was to compare assessments of sperm concentration and sperm motility analysed by conventional semen analysis with those obtained by computer-assisted semen analysis （CASA） （Copenhagen Rigshospitalet Image House Sperm Motility Analysis System （CRISMAS） 4.6 software） using semen samples from 166 young Danish men. The CRISMAS software identifies sperm concentration and classifies spermatozoa into three motility categories. To enable comparison of the two methods, the four motility stages obtained by conventional semen analysis were, based on their velocity classifications, divided into three stages, comparable to the three CRISMAS motility categories： rapidly progressive （A）, slowly progressive （B） and non-progressive （C＋ D）. Differences between the two methods were large for all investigated parameters （P〈0.001）. CRISMAS overestimated sperm concentration and the proportion of rapidly progressive spermatozoa and, consequently, underestimated the percentages of slowly progressive and non-progressive spermatozoa, compared to the conventional method. To investigate whether results drifted according to time of semen analysis, results were pooled into quarters according to date of semen analysis. CRISMAS motility results appeared more stable over time compared to the conventional analysis; however, neither method showed any trends. Apparently, CRISMAS CASA results and results from the conventional method were not comparable with respect to sperm concentration and motility analysis. This needs to be accounted for in clinics using this software and in studies of determinants of these semen characteristics.
