BackgroundPerfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) are man-made, ubiquitous, and persistent contaminants in the environment, wildlife, and humans. Although recent studies have shown that these chemicals interfere with fetal growth in humans, the results are inconsistent.ObjectivesOur goal was to investigate the correlation between relatively low levels of PFOS and PFOA in maternal serum and birth weight and birth size.MethodsWe conducted a hospital-based prospective cohort study between July 2002 and October 2005 in Sapporo, Japan. A total of 428 women and their infants were involved in the study. We obtained characteristics of the mothers and infants from self-administered questionnaire surveys and from medical records. We analyzed maternal serum samples for PFOS and PFOA by liquid chromatography–tandem mass spectrometry (LC/MS/MS).ResultsAfter adjusting for confounding factors, PFOS levels negatively correlated with birth weight [per log10 unit: β = −148.8 g; 95% confidence interval (CI), −297.0 to −0.5 g]. In addition, analyses stratified by sex revealed that PFOS levels negatively correlated with birth weight only in female infants (per log10 unit: β = −269.4 g; 95% CI, −465.7 to −73.0 g). However, we observed no correlation between PFOA levels and birth weight.ConclusionOur results indicate that in utero exposure to relatively low levels of PFOS was negatively correlated with birth weight.

We evaluated the effects of inhaled di(2-ethylhexyl)phthalate (DEHP) on the onset of puberty and on postpubertal reproductive functions in prepubertal female rats. DEHP was administered by inhalation at doses of 0, 5, and 25 mg/m3 to groups of female rats for 6 h/day, 5 contiguous days/week from postnatal days (PNDs) 22 to 41 and to PND 84. The onset of puberty was determined by daily examination for vaginal opening (VO) and first estrous cycle. Reproductive function was evaluated by observing estrous cyclicity from PNDs 49 to 84. Upon completion of exposure, the rats were sacrificed at PND 42 and PNDs 85-88 during the diestrous stage. DEHP exposure advanced the age of VO and first estrous cycle, and serum cholesterol, luteinizing hormone, and estradiol levels were significantly elevated in the 25-mg/m3 DEHP group. Irregular estrous cycles were observed more frequently in DEHP-exposed rats, and serum cholesterol decreased in DEHP-exposed rats in adulthood; RT-PCR showed that the expression of aromatase mRNA, encoding a rate-limiting enzyme that catalyzes the conversion of testosterone to estradiol, was elevated in the 25-mg/m3 DEHP group. These data suggest that inhaled DEHP may advance the onset of puberty and alter postpubertal reproductive functions.

Several human studies have shown that low-level exposure to environmental contaminants, such as polychlorinated biphenyls (PCBs) and organochlorine pesticides, negatively influences birth outcomes.However, the effects of low-level exposure to polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like PCBs (DL-PCBs) on birth outcomes have not been clarified in human studies.A prospective cohort study was established to investigate the possible adverse effects of PCDDs/PCDFs and DL-PCBs on fetal growth and neurodevelopment. We recruited 514 pregnant women between July 2002 and October 2005 in Sapporo, Japan. We measured 29 congener levels of PCDDs/PCDFs and DL-PCBs in maternal blood.Using multiple liner regression analysis of the association between birth weight and the levels of PCDDs/PCDFs and DL-PCBs with full adjustments for potential confounders, a significant adverse effect was observed regarding total PCDDs toxic equivalents (TEQ) levels (adjusted β = -231.5 g, 95% CI: -417.4 to -45.6) and total PCDFs TEQ levels (adjusted β = -258.8 g, 95% CI: -445.7 to -71.8). Among male infants, significant adverse associations with birth weight were found for total PCDDs TEQ level, total PCDDs/PCDFs TEQ level, and total TEQ level. However, among female infants, these significant adverse associations were not found. With regard to individual congeners of PCDDs/PCDFs and DL-PCBs, we found significantly negative association with the levels of 2,3,4,7,8-PeCDF (adjusted β = -24.5 g, 95% CI: -387.4 to -61.5).Our findings suggest that prenatal low-level exposure to PCDDs and PCDFs, especially 2,3,4,7,8-PeCDF, may accumulate in the placenta and retard important placental functions, which result in lower birth weight.

Ascidians are hermaphrodites releasing sperm and eggs simultaneously, but many species are self-sterile because of a self͞nonself-recognition system in sperm-egg interaction. Here, we show that a 70-kDa vitelline coat protein, HrVC70, consisting of 12 epidermal growth factor-like repeats, plays a key role in self͞nonself recognition during ascidian fertilization. We discovered that the amount of HrVC70 of the self-sterile mature oocytes is markedly higher than that of the self-fertile immature oocytes and that the selfsterile mature oocytes become self-fertile by acid treatment, which is able to release the HrVC70 from isolated vitelline coats. In addition, fertilization is strongly inhibited by the pretreatment of sperm with HrVC70 from a different individual, but not from the same individual, and the number of nonself sperm bound to HrVC70-agarose was significantly higher than that of self-sperm. A sequence analysis of HrVC70 disclosed that several amino acid residues in a restricted region are substituted at an individual level, with no identical sequences among the 10 individuals tested. Furthermore, genomic DNA analysis revealed that the epidermal growth factor-like domains correspond to the exons, and each intron is highly conserved among even-and odd-numbered introns, suggesting that multiple gene duplications or amplification of this region might have taken place during evolution. It was also found that diversity in cDNA sequences is derived from genomic DNA polymorphism probably elicited by crossing over and specific nucleotide substitutions. These results indicate that HrVC70 is a candidate allogeneic recognition molecule in the gamete interaction of the ascidian Halocynthia roretzi.