Ejaculate volume is seriously underestimated when semen is pipetted or decanted into cylinders from the collection vessel.
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Ejaculation↗
Biomedical subjects
James W Overstreet
Publications and source records attributed to James W Overstreet.
Semen and sperm reference ranges for men 45 years of age and older.
The most widely used reference values for human semen and sperm variables were developed by the World Health Organization (WHO) to help assess the fertility status of men interested in reproduction (typically a younger population). In this retrospective analysis, data from a large population of men aged 45 years or older were analyzed to derive semen and sperm reference ranges for an older population. Baseline semen samples were obtained from 1174 men with no or mild erectile dysfunction (ED) during the screening phase of two clinical trials evaluating the effects of a drug on human spermatogenesis. The median values and 95% reference ranges for 4 measured semen and sperm parameters (semen volume, sperm concentration, sperm motility, and sperm morphology) and 1 derived parameter (total sperm count) were calculated for the population and by age quartile. These references ranges were compared to established WHO reference values. Associations between the semen and sperm parameters and smoking status, alcohol use, and serum hormone concentrations were also analyzed. The mean age was 52.9 years (range: 45-80). Median semen volume, sperm motility, and sperm morphology parameters declined significantly with age. Only 46% of study subjects had baseline values for semen and sperm parameters that met or surpassed all the WHO reference values. This is the first study to statistically derive semen reference ranges from a large population of men aged 45 years or older. The observation that less than half the men in this study met all 4 WHO reference values for measured semen and sperm parameters underscores the need for age-specific reference ranges.
Aging↗
Hyperactivation of monkey spermatozoa is triggered by Ca2+ and completed by cAMP.
Digital image analysis of the flagellar movements of cynomolgus macaque spermatozoa hyperactivated by caffeine and cAMP was carried out to understand the change in flagellar movements during hyperactivation. The degree of flagellar bending increased remarkably after hyperactivation, especially at the base of the midpiece. Mainly two beating patterns were seen in the hyperactivated monkey sperm flagella: remarkably asymmetrical flagellar bends of large amplitude and relatively symmetrical flagellar bends of large amplitude. The asymmetrical bends were often seen in the early stage of hyperactivation, whereas the symmetrical bends executed nonprogressive, figure-of-eight movement. Beat frequency of the hyperactivated spermatozoa significantly decreased while wavelength of flagellar waves roughly doubled. To determine the conditions under which the axonemes of hyperactivated sperm flagella have asymmetrical or symmetrical bends, the plasma membranes of monkey spermatozoa were extracted with Triton X-100 and motility was reactivated with MgATP(2-) under various conditions. The asymmetrical flagellar bends were brought about by Ca(2+), whereas the symmetrical flagellar bends resulted from low levels of Ca(2+) and high levels of cAMP. Under these conditions, beat frequency and wavelength of flagellar waves of demembranated, reactivated spermatozoa were similar to those of the hyperactivated spermatozoa. These results suggest that during hyperactivation of monkey spermatozoa intracellular Ca(2+) concentrations first rise, and then decrease while cAMP concentrations increase simultaneously.
Animals↗
Beta-defensin 126 on the cell surface protects sperm from immunorecognition and binding of anti-sperm antibodies.
Beta-defensin 126 (DEFB126), formerly known as epididymal secretory protein 13.2 (ESP13.2), coats the entire primate sperm surface until completion of capacitation, and it is a candidate for providing immune protection in the female reproductive tract. To further examine the potential role of DEFB126 as a means of protection from immune recognition, cynomolgus macaque sperm were exposed to a number of treatments that are known to alter sperm surface coats, including capacitation. We used a novel in vivo assay to determine immune recognition: aldehyde-fixed whole sperm injections into rabbits. Following booster injections, immunoblot analyses of whole sperm prepared in various manners was conducted. On Days 60 and 80 post-initial immunization, the antisera showed a remarkably strong reaction to a single 34-36 kDa protein, which was shown to be DEFB126. Sera from rabbits that were immunized with sperm washed more rigorously using Percoll gradients showed an increase in the number and intensity of proteins recognized on whole sperm Western blots, although DEFB126 was still the major immune response. When capacitated sperm, from which most DEFB126 had been released, were used as the immunogen, there was a dramatic increase in the immune recognition to a variety of protein bands. Sperm treated with neuraminidase to remove sialic acid on DEFB126 before fixation were shown to still possess DEFB126, but lacked the sialic acid component of the glycoprotein. These sperm were as immunogenic as capacitated sperm even though the desialylated DEFB126 still covered the entire cell surface. These sperm lost their highly negative charge (the isoelectric point of DEFB126 shifted from pI 3.0 to pI 6.4). Experiments using different sperm plasma membrane protein-specific Igs showed that recognition did not occur when DEFB126 was present, but following capacitation these Igs readily recognized the exposed sperm membrane. Our data suggest that DEFB126 protects the entire primate sperm surface from immune recognition and that the sialic acid moieties are responsible for the cloaking characteristic of this unique glycoprotein.
Animals↗
Secretion and excretion of human chorionic gonadotropin during early pregnancy.
OBJECTIVE: To characterize the profiles of human chorionic gonadotropin (hCG) secretion in blood and its subsequent excretion in urine during conceptive cycles that ended in successful pregnancy and in spontaneous abortion. DESIGN: A prospective study. SETTING: University fertility clinic and research laboratories. PATIENT(S): Healthy, spontaneously ovulating women with regular menses, no history of infertility, and either no male partner or an azoospermic partner. INTERVENTION(S): Blood and urine samples were collected daily from 63 spontaneously ovulating women during 167 cycles of artificial insemination (AI) with donor semen; hCG concentrations were measured in blood and urine, and luteinizing hormone (LH) and follicle-stimulating hormone (FSH) concentrations were measured in blood by immunoassay. MAIN OUTCOME MEASURE(S): Fecundity, the day of ovulation, the day of hCG detection, and the concentration of hCG on the day of detection in blood and urine. RESULT(S): In 62 conceptions detected, 14 resulted in clinical spontaneous abortion (CAB) and 8 resulted in early pregnancy loss (EPL). When successful pregnancies and pregnancy losses were compared, no significant differences existed between the days of hCG appearance in serum or in urine, the concentrations of hCG on the day of detection, or the incremental change in hCG concentration on the day of detection. CONCLUSION(S): These data validate the use of urinary hCG as a biomarker for assessing peri-implantation pregnancy events.
Abortion, Spontaneous↗
Effect of environmental tobacco smoke on levels of urinary hormone markers.
Our recent study showed a dose-response relationship between environmental tobacco smoke (ETS) and the risk of early pregnancy loss. Smoking is known to affect female reproductive hormones. We explored whether ETS affects reproductive hormone profiles as characterized by urinary pregnanediol-3-glucuronide (PdG) and estrone conjugate (E1C) levels. We prospectively studied 371 healthy newly married nonsmoking women in China who intended to conceive and had stopped contraception. Daily records of vaginal bleeding, active and passive cigarette smoking, and daily first-morning urine specimens were collected for up to 1 year or until a clinical pregnancy was achieved. We determined the day of ovulation for each menstrual cycle. The effects of ETS exposure on daily urinary PdG and E1C levels in a +/-10 day window around the day of ovulation were analyzed for conception and nonconception cycles, respectively. Our analysis included 344 nonconception cycles and 329 conception cycles. In nonconception cycles, cycles with ETS exposure had significantly lower urinary E1C levels (beta = -0.43, SE = 0.08, p < 0.001 in log scale) compared with the cycles without ETS exposure. There was no significant difference in urinary PdG levels in cycles having ETS exposure (beta = -0.07, SE = 0.15, p = 0.637 in log scale) compared with no ETS exposure. Among conception cycles, there were no significant differences in E1C and PdG levels between ETS exposure and nonexposure. In conclusion, ETS exposure was associated with significantly lower urinary E1C levels among nonconception cycles, suggesting that the adverse reproductive effect of ETS may act partly through its antiestrogen effects.
Adult↗
Macaque sperm release ESP13.2 and PSP94 during capacitation: the absence of ESP13.2 is linked to sperm-zona recognition and binding.
ESP13.2 coats the entire surface of macaque sperm and remains until sperm become capacitated (Yudin et al., 2003: Biol Reprod 69: 1118-1128). Capacitation of macaque sperm is synchronized by treatment with dibutyrl cAMP (dbcAMP) and caffeine. ESP13.2 and PSP94 constituted approximately 95% of the proteins released from the sperm surface following treatment with caffeine + dbcAMP. Caffeine and dbcAMP alone induce different patterns of ESP13.2 release. As determined by ELISAs of supernatants and immuno-fluorescent labeling of sperm heads, caffeine alone and caffeine + dbcAMP induced comparable release of ESP13.2, while dbcAMP-treated sperm did not differ from controls. Sperm treated with caffeine + dbcAMP showed a reduction of ESP13.2 from the entire surface, while caffeine treatment alone induced removal of ESP13.2 from the sperm head and midpiece. As confirmed with immunofluorescence, ESP13.2 could be added back to the surfaces of sperm that had been previously exposed to caffeine. Treatment with caffeine significantly increased the number of sperm that bound tightly to the zona pellucida as compared with controls (42 +/- 9 and 13 +/- 3 sperm/zona, respectively; P < or = 0.01). This increase in binding was inhibited by "adding back" ESP13.2 to the sperm surface (12.8 +/- 3; P < or = 0.01). Alexa-conjugated anti-ESP13.2 Ig labeling of live sperm showed that only sperm lacking ESP13.2 over the head were capable of tight binding to the zona. Our results suggest that ESP13.2 masks zona pellucida ligands on the sperm surface and its release, as part of capacitation, is required for sperm-zona interaction.
Amino Acid Sequence↗
Bromodichloromethane inhibits human placental trophoblast differentiation.
Epidemiological data suggest an association between exposures to bromodichloromethane (BDCM), a trihalomethane found in drinking water as a result of drinking water disinfection, and an increased risk of spontaneous abortion. We previously hypothesized that BDCM targets the placenta and showed that the secretion of chorionic gonadotrophin (CG) was reduced in primary cultures of human term syncytiotrophoblasts exposed to BDCM. In the present study we extend this observation by evaluating the effects of BDCM on the morphological differentiation of mononucleated cytotrophoblast cells to multinucleated syncytiotrophoblast-like colonies. Addition of BDCM to cytotrophoblast cultures inhibited the subsequent formation of multinucleated colonies in a dose-dependent manner, as determined by immunocytochemical staining for desmosomes and nuclei. The effect was seen at BDCM concentrations between 0.02 and 2 mM and was confirmed by quantitative image analysis. Secretion of bioactive and immunoreactive chorionic gonadotropin was also significantly inhibited in a dose-dependent manner under these culture conditions, and cellular levels of CG were also reduced. Trophoblast viability was not compromised by exposure to BDCM. We conclude that BDCM disrupts syncytiotrophoblast formation and inhibits CG secretion in vitro. Although other tissue targets are not ruled out, these data substantiate the idea that BDCM targets the placenta and could have implications for understanding the adverse pregnancy outcomes associated with BDCM exposure in humans.
Adult↗
Effect of bromodichloromethane on chorionic gonadotrophin secretion by human placental trophoblast cultures.
Bromodichloromethane (BDCM) is a trihalomethane found in drinking water as a by-product of disinfection processes. BDCM is hepatotoxic and nephrotoxic in rodents and has been reported to cause strain-specific full-litter resorption in F344 rats during the luteinizing hormone-dependent phase of pregnancy. In humans, epidemiological studies suggest an association between exposure to BDCM in drinking water and increased risk of spontaneous abortion. To begin to address the mechanism(s) of BDCM-induced spontaneous abortion, we hypothesized that BDCM targets the placenta. Primary cultures of human term trophoblast cells were used as an in vitro model to test this hypothesis. Trophoblasts were allowed to differentiate into multinucleated syncytiotrophoblast-like colonies, after which they were incubated for 24 h with different concentrations of BDCM (20 nM to 2 mM). Culture media were collected and assayed for immunoreactive and bioactive chorionic gonadotropin (CG). Cultures exposed to BDCM showed a dose-dependent decrease in the secretion of immunoreactive CG as well as bioactive CG. The lowest effective BDCM concentration was 20 nM, approximately 35-times higher than the maximum concentration reported in human blood (0.57 nM). Trophoblast morphology and viability were similar in controls and cultures exposed to BDCM. We conclude that BDCM perturbs CG secretion by differentiated trophoblasts in vitro. This suggests that the placenta is a likely target of BDCM toxicity in the human and that this could be related to the adverse pregnancy outcomes associated with BDCM.
Cell Survival↗
Tolerance of the mouse sperm nuclei to freeze-drying depends on their disulfide status.
Mouse spermatozoa from the caudae epididymides could be freeze-dried without losing their ability to support normal development. Immature spermatozoa from the testes, in contrast, were damaged by freeze-drying. However, immature spermatozoa became resistant to freeze-drying after their treatment with diamide, which oxidizes free -SH groups. Conversely, epididymal spermatozoa were damaged by freeze-drying if first treated with dithiothreitol (DTT), which reduces -SS- bonds. The potential for freeze-drying damage seems likely to relate to the -SS- status of sperm proteins, in particular its protamines.
Animals↗
ESP13.2, a member of the beta-defensin family, is a macaque sperm surface-coating protein involved in the capacitation process.
Female macaques produced isoantibodies to a limited number of sperm surface proteins following immunization with sperm components released by phosphatidylinositol-specific phospholipase C (PI-PLC). Washed, acrosome-intact, fixed sperm injected into rabbits elicited a major immune response to one of the same PI-PLC-released proteins, which was shown to be a sperm surface-coating protein. After purification and digestion of the glycoprotein, four peptides were analyzed for amino acid sequence, and all had 100% homology with an epididymal secretory protein, ESP13.2, reported previously to be a small, cationic-rich peptide and a member of the beta-defensin family. Antibodies to purified ESP13.2 recognized a number of protein bands on Western blots of nonreduced PI-PLC-released sperm components and nonreduced whole-sperm extracts. After chemical disulfide reduction, only a single, broad band from 31 to 35 kDa was recognized by anti-ESP13.2 antibodies. Indirect immunofluorescence showed ESP13.2 over the entire surface of ejaculated macaque sperm. Fluorescence was only slightly reduced after sperm were washed through 80% Percoll. A 24-h incubation in capacitating medium significantly reduced the amount of ESP13.2 over the head and midpiece, whereas exposure of the incubated sperm to dbcAMP and caffeine (capacitation activators) resulted in almost complete loss of ESP13.2 from the sperm surface. After activation, ESP13.2 was the primary component released into the medium as judged electrophoretically. Lignosulfonic acid, a potent inhibitor of macaque fertilization in vitro, completely blocked release of ESP13.2 from the sperm surface, even following treatment with activators. These findings suggest that the beta-defensin, ESP13.2, has a function in the capacitation of macaque spermatozoa and may modulate sperm surface-receptor presentation at the time of fertilization.
Amino Acid Sequence↗
The effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on chorionic gonadotrophin activity in pregnant macaques.
As many as 62% of all human conceptions are lost prior to 12 weeks of pregnancy and it is unknown how many of these losses result from environmental hazards. Previous studies have shown that single doses of 1, 2, and 4 microg/kg 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) administrated orally to cynomolgus macaques during the peri-implantation period leads to early fetal loss (EFL) within 10-20 days. TCDD induced EFL is associated with a reduction in the biological activity of monkey chorionic gonadotrophin (mCG) but no change in the immunoreactive mCG profile. These studies are consistent with either a direct effect of TCDD on differentiation of the trophoblast and an indirect effect on mCG synthesis, or a direct effect on mCG synthesis and secretion independent of trophoblast development. The present study was designed to test the hypothesis that the action of TCDD is directly on mCG synthesis rather than on the differentiation of the trophoblast. Female macaques (Macaca fascicularis) were treated with a single dose of TCDD (4 microg/kg b.wt.) on Gestational Day 20, a stage of pregnancy following initial trophoblast differentiation and invasion. Circulating mCG concentrations were monitored for the next 6 days. Compared to the controls, the peak level of serum bioactive mCG was lower in the treated group (P<0.05), with a decrease observed on the day following exposure. The bioactive/immunoreactive mCG ratio was also lower in the treated group compared to the controls (P<0.05). There was no difference in serum immunoreactive mCG levels between the groups. Histological evaluation of the embryo-placental unit showed increased apoptosis and vascular congestion after treatment but was otherwise grossly normal. Because exposure of the conceptus to TCDD following differentiation of the trophoblast decreased the bioactivity of circulating mCG, we conclude that the action of TCDD in the placenta is directly on mCG synthesis.
Animals↗
Real-time observations of individual macaque sperm undergoing tight binding and the acrosome reaction on the zona pellucida.
Changes in binding affinity, acrosomal status, and motility of living sperm on the zona pellucida were for the first time in any mammalian species directly observed and analyzed with video microscopy. A single zona was air-dried and rehydrated on a microscope slide, and a coverslip supported by glass beads was added. Capacitated sperm were added together with Alexa-SBTI, a probe for acrosin that can detect the acrosome reaction. The heads of loosely attached sperm oscillated on the zona and the flagella beat symmetrically with a sigmoid-shaped waveform. Tight binding was observed after 16 sec as the sperm head became fixed in place on the zona. The shape of the flagellar beat simultaneously shifted to a more rigid, C-shaped waveform. The first signs of the acrosome reaction were detected within 11 sec of tight binding. Rapid flushing removed approximately 65% of sperm that were loosely attached but only 2% of those that were tightly bound. In the 2 min following the onset of tight binding, the lateral displacement of the flagellum increased by approximately 30% and the beat frequency decreased by 25%. Lignosulfonic acid (LSA) inhibited loose sperm attachment and the development of tight binding. LSA had no effect on the time of the acrosome reaction following tight binding or on changes in motility that followed tight binding. These data suggest that LSA affects the initial attachment or docking of sperm to the zona, a step that may align or recruit one or more specific zona receptors to be responsible for mediating the acrosome reaction.
Acrosome Reaction↗
Trihalomethane levels in home tap water and semen quality.
BACKGROUND: Trihalomethanes (THMs) are byproducts of drinking water chlorination whose effects on semen quality have not been previously studied in humans. METHODS: We examined the relationship of THMs to semen quality in 157 healthy men from couples without known risk factors for infertility. Total THM (TTHM) levels were assigned based on water utility measurements taken during the 90 days preceding semen collection. We analyzed continuous semen parameters in relation to total and individual THMs, adjusting for potential confounders by using repeated measures analyses. RESULTS: TTHM level was not associated with decrements in semen quality. Percent normal morphology decreased and percent head defects increased at higher levels of an ingestion metric (TTHM multiplied by cold home tap water consumption). At the highest level of the ingestion metric (>160 mug/L x glasses/day, which is equivalent to >2 glasses/day of water containing 80 mug/L) we observed a difference of -7.1 (95% confidence interval = -12.7 to -1.6) for percent morphologically normal sperm compared with the lowest level (</= 40 mug/L x glasses/day). Of the individual THMs, bromodichloromethane exposure was inversely related to linearity (a motility parameter); we observed a small decrease (beta = -0.09, SE 0.04) for every unit increase in bromodichloromethane. CONCLUSION: Although our study had a limited exposure assessment and a selective sample, our results suggest the need for further study of the effects of THMs on semen quality.
Adolescent↗
Tadalafil has no detrimental effect on human spermatogenesis or reproductive hormones.
PURPOSE: We assessed the effects on spermatogenesis of placebo vs 10 or 20 mg tadalafil administered daily for 6 months to healthy men and men with mild erectile dysfunction. MATERIALS AND METHODS: In 2 studies 421 healthy men or men with mild erectile dysfunction who were 45 years or older and met semen criteria derived from WHO reference values were randomized to 6 months of treatment with placebo (101) or 10 mg tadalafil (103), or to placebo (106) or 20 mg tadalafil (111). Semen samples and serum for reproductive hormones (testosterone, luteinizing hormone and follicle-stimulating hormone) were collected at baseline, after 3 months and at the end of treatment. RESULTS: Tadalafil had no adverse effects on spermatogenesis, as assessed by sperm concentration, sperm count per ejaculate, percent sperm motility, normal morphology or serum reproductive hormones. Tadalafil was well tolerated. Common adverse events were headache, dyspepsia and back pain. CONCLUSIONS: Chronic daily administration of tadalafil at doses of 10 and 20 mg for 6 months had no adverse effects on spermatogenesis or on reproductive hormones in men older than 45 years.
3',5'-Cyclic-GMP Phosphodiesterases↗
Bone resorption is affected by follicular phase length in female rotating shift workers.
Stressors as subtle as night work or shift work can lead to irregular menstrual cycles, and changes in reproductive hormone profiles can adversely affect bone health. This study was conducted to determine if stresses associated with the disruption of regular work schedule can induce alterations in ovarian function which, in turn, are associated with transient bone resorption. Urine samples from 12 rotating shift workers from a textile mill in Anqing, China, were collected in 1996-1998 during pairs of sequential menstrual cycles, of which one was longer than the other (28.4 vs. 37.4 days). Longer cycles were characterized by a prolonged follicular phase. Work schedules during the luteal-follicular phase transition (LFPT) preceding each of the two cycles were evaluated. All but one of the shorter cycles were associated with regular, forward phase work shift progression during the preceding LFPT. In contrast, five longer cycles were preceded by a work shift interrupted either by an irregular shift or a number of "off days." Urinary follicle-stimulating hormone levels were reduced in the LFPT preceding longer cycles compared with those in the LFPT preceding shorter cycles. There was greater bone resorption in the follicular phase of longer cycles than in that of shorter cycles, as measured by urinary deoxypyridinoline. These data confirm reports that changes in work shift can lead to irregularity in menstrual cycle length. In addition, these data indicate that there may be an association between accelerated bone resorption in menstrual cycles and changes of regularity in work schedule during the preceding LFPT.
Adult↗
Geographic differences in semen quality of fertile U.S. males.
Although geographic variation in semen quality has been reported, this is the first study in the United States to compare semen quality among study centers using standardized methods and strict quality control. We evaluated semen specimens from partners of 512 pregnant women recruited through prenatal clinics in four U.S. cities during 1999-2001; 91% of men provided two specimens. Sperm concentration, semen volume, and motility were determined at the centers, and morphology was assessed at a central laboratory. Study protocols were identical across centers, and quality control was rigorously maintained. Sperm concentration was significantly lower in Columbia, Missouri, than in New York, New York; Minneapolis, Minnesota; and Los Angeles, California. Mean counts were 58.7, 102.9, 98.6, and 80.8 X 10(6)/mL (medians 53.5, 88.5, 81.8, and 64.8 X 10(6)/mL) in Missouri, New York, Minnesota, and California, respectively. The total number of motile sperm was also lower in Missouri than in other centers: 113, 196, 201, and 162 X 10(6) in Missouri, New York, Minnesota, and California, respectively. Semen volume and the percent morphologically normal sperm did not differ appreciably among centers. These between-center differences remained significant in multivariate models that controlled for abstinence time, semen analysis time, age, race, smoking, history of sexually transmitted disease, and recent fever (all p-values < 0.01). Confounding factors and differences in study methods are unlikely to account for the lower semen quality seen in this mid-Missouri population. These data suggest that sperm concentration and motility may be reduced in semirural and agricultural areas relative to more urban and less agriculturally exposed areas.
Adult↗
Semen quality in relation to biomarkers of pesticide exposure.
We previously reported reduced sperm concentration and motility in fertile men in a U.S. agrarian area (Columbia, MO) relative to men from U.S. urban centers (Minneapolis, MN; Los Angeles, CA; New York, NY). In the present study we address the hypothesis that pesticides currently used in agriculture in the Midwest contributed to these differences in semen quality. We selected men in whom all semen parameters (concentration, percentage sperm with normal morphology, and percentage motile sperm) were low (cases) and men in whom all semen parameters were within normal limits (controls) within Missouri and Minnesota (sample sizes of 50 and 36, respectively) and measured metabolites of eight current-use pesticides in urine samples provided at the time of semen collection. All pesticide analyses were conducted blind with respect to center and case-control status. Pesticide metabolite levels were elevated in Missouri cases, compared with controls, for the herbicides alachlor and atrazine and for the insecticide diazinon [2-isopropoxy-4-methyl-pyrimidinol (IMPY)]; for Wilcoxon rank test, p = 0.0007, 0.012, and 0.0004 for alachlor, atrazine, and IMPY, respectively. Men from Missouri with high levels of alachlor or IMPY were significantly more likely to be cases than were men with low levels [odds ratios (ORs) = 30.0 and 16.7 for alachlor and IMPY, respectively], as were men with atrazine levels higher than the limit of detection (OR = 11.3). The herbicides 2,4-D (2,4-dichlorophenoxyacetic acid) and metolachlor were also associated with poor semen quality in some analyses, whereas acetochlor levels were lower in cases than in controls (p = 0.04). No significant associations were seen for any pesticides within Minnesota, where levels of agricultural pesticides were low, or for the insect repellent DEET (N,N-diethyl-m-toluamide) or the malathion metabolite malathion dicarboxylic acid. These associations between current-use pesticides and reduced semen quality suggest that agricultural chemicals may have contributed to the reduction in semen quality in fertile men from mid-Missouri we reported previously.
Adult↗