Comparative study of human and mouse pregnane X receptor agonistic activity in 200 pesticides using in vitro reporter gene assays

The nuclear receptor, pregnane X receptor (PXR), is a ligand-dependent transcription factor that regulates genes involved in xenobiotic metabolism. Recent studies have shown that PXR activation may affect energy metabolism as well as the endocrine and immune systems. In this study, we characterized and compared the agonistic activities of a variety of pesticides against human PXR (hPXR) and mouse PXR (mPXR). We tested the hPXR and mPXR agonistic activity of 200 pesticides (29 organochlorines, 11 diphenyl ethers, 56 organophosphorus pesticides, 12 pyrethroids, 22 carbamates, 12 acid amides, 7 triazines, 7 ureas, and 44 others) by reporter gene assays using COS-7 simian kidney cells. Of the 200 pesticides tested, 106 and 93 activated hPXR and mPXR, respectively, and a total of 111 had hPXR and/or mPXR agonistic activity with greater or lesser inter-species differences. Although all of the pyrethroids and most of the organochlorines and acid amides acted as PXR agonists, a wide range of pesticides with diverse structures also showed hPXR and/or mPXR agonistic activity. Among the 200 pesticides, pyributicarb, pretilachlor, piperophos and butamifos for hPXR, and phosalone, prochloraz, pendimethalin, and butamifos for mPXR, acted as particularly potent activators at low concentrations in the order of 10⁻⁸-10⁻⁷ M. In addition, we found that several organophosphorus oxon- and pyributicarb oxon-metabolites decreased PXR activation potency compared to their parent compounds. These results suggest that a large number of structurally diverse pesticides and their metabolites possess PXR-mediated transcriptional activity, and their ability to do so varies in a species-dependent manner in humans and mice.

Near-infrared spectrophotometry is useful to detect the beneficial pharmacological effects of alprostadil on spinal cord deoxygenation

PURPOSE

The purpose of this study is to confirm our previous studies that near-infrared spectrophotometry (NIRS) can detect spinal cord ischemia earlier than evoked spinal cord potential (ESP), and to determine whether it can detect the pharmacological effect of prostaglandin E1 (PGE1) incorporated in lipid microspheres (alprostadil) on the spinal cord.

MATERIALS AND METHODS

NIRS probes were placed on the posterior side of the lower lumbar vertebrae, and oxygenated hemoglobin (oxy-Hb) of the spinal cord was monitored continuously in 14 male New Zealand white rabbits. The amplitude of ESP was recorded every minute. All rabbits underwent a normothermic infrarenal aortic cross-clamping (AXC) for 20 min, and all were pretreated with either an intravenous 3 microg/kg/10 min alprostadil (group A; n=4) or the same volume saline (group C; n=10).

RESULTS

ESP amplitude started to show a linear decrease 6 min after the onset of AXC and was comparable between groups (P=.839). Oxy-Hb decreased rapidly just after the onset of AXC, followed by monoexponential decline. It reached a plateau at 10 min after the onset of AXC. Oxy-Hb of group A was significantly higher than that of group C (P=.014).

CONCLUSIONS

NIRS can detect spinal cord ischemia earlier than ESP. It can detect the beneficial pharmacological effect of alprostadil on the spinal cord.

Congener-specific analysis of non-dioxin-like polychlorinated biphenyls in blood collected from 195 pregnant women in Sapporo City, Japan

We conducted a congener-specific analysis of non-dioxin-like polychlorinated biphenyls (non-dioxin-like PCBs) in blood collected between July 2002 and July 2004 from 195 pregnant women living in Sapporo City of Hokkaido Prefecture, Japan. The present study is one of the few studies in which full congener concentrations of non-dioxin-like PCBs have been measured in the blood of pregnant women. Of the 195 pregnant women, 101 were primipara (mean: 28.8 years, median: 28.0 years) and 94 were multipara (mean: 32.3 years, median: 33.0 years). Among the 197 non-dioxin-like PCB congeners, 58 congeners were identified in the blood of pregnant women. The arithmetic mean total concentrations of 58 non-dioxin-like PCB congeners in the blood of primiparous and multiparous mothers in Sapporo City were 42.2-329.3 (mean: 114.5, median: 98.6) and 31.5-258.0 (mean: 100.3, median: 91.4)ngg(-1)lipid, respectively. The results show that the contamination of non-dioxin-like PCBs in the blood of women has decreased compared to past levels in other domestic areas, in which the subject age was similar to that in this study. The results of the present study indicate that current levels of non-dioxin-like PCBs in the blood of Japanese women and can be used as baseline data for future temporal trends. The sums of the ratios of the concentrations of hexaCBs and heptaCBs to the total concentrations of 58 non-dioxin-like PCB congeners in the blood of primiparous and multiparous mothers were 78.5% and 77.7%, respectively. The hexaCBs ratios in the blood of primiparous and multiparous mothers were 45.4% and 44.7%, respectively. HexaCB-153 among hexaCBs congeners, the most abundant congener in the blood of primiparous and multiparous mothers, contributed approximately 22.0% and 21.8% to the total concentrations of 58 non-dioxin-like PCBs congeners that were measured in the blood, respectively. Among the non-dioxin-like PCB congeners measured in the present study, hexaCB-138, heptaCB-170, heptaCB-180, and heptaCB-182/heptaCB-187 also showed high ratios to total concentrations of 58 non-dioxin-like PCB congeners detected in the blood of primiparous and multiparous mothers. With regard to the relationship between the total concentrations of 58 non-dioxin-like PCB congeners in maternal blood and the number of deliveries or the age of primiparous and multifarious mothers, the total levels of these PCB congeners tended to decreases with increases in the number of deliveries and significantly increased with increasing maternal age in both groups. Furthermore, significant correlations were observed between the total concentrations of these PCB congeners in blood and the age of primiparae and multiparae. The concentrations of hexaCB-153 in the blood of primiparous and multiparous mothers showed a close correlation to the total concentrations of these PCBs, suggesting that hexaCB-153 could be an indicator of total concentrations of non-dioxin-like PCB congeners in the blood of pregnant women.

Concentrations of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and dioxin-like polychlorinated biphenyls in blood and breast milk collected from 60 mothers in Sapporo City, Japan

We measured the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), non-ortho polychlorinated biphenyls (non-ortho PCBs), and mono-ortho polychlorinated biphenyls (mono-ortho PCBs) in paired samples of blood and breast milk collected from 60 mothers in Sapporo City, Hokkaido Prefecture, Japan. The present study is one of the few studies in which PCDDs, PCDFs, and dioxin-like PCBs have been measured in blood and breast milk collected from 60 same mothers. Of these 60 mothers, 30 were primipara (mean: 30.1 years, median: 28.0 years) and 30 were multipara (mean: 32.2 years, median: 32.5 years). The arithmetic mean TEQ concentrations of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs in blood and breast milk of the primiparous mothers were 9.0, 3.3, 5.7, and 0.4 pg TEQ g(-1) lipid, respectively, and 5.2, 2.2, 4.5, and 0.4 pg TEQ g(-1) lipid, respectively, with the total TEQ concentrations of these dioxin-like compounds being 9.3-42.9 (mean: 18.4, median: 17.3) and 7.0-41.1 (mean: 12.3, median: 11.4) pg TEQ g(-1) lipid, respectively. In the case of multiparous mothers, the arithmetic mean TEQ concentrations of these dioxin-like compounds in blood and breast milk were 7.1, 2.7, 5.3, and 0.4 pg TEQ g(-1) lipid, respectively, and 3.9, 1.7, 3.8, and 0.4 pg TEQ g(-1) lipid, respectively, with the total TEQ concentrations being 3.4-28.1 (mean: 15.5, median: 13.9) and 2.7-20.0 (mean: 9.8, median: 9.2)pg TEQ g(-1) lipid, respectively. The total TEQ concentrations of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs in blood and breast milk of primiparous mothers in Sapporo City appeared to be generally lower than those recently surveyed throughout the greater area of Japan. Significant correlations were observed between age and the total TEQ concentrations of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs in the blood of primiparae and multiparae, and significant correlations were also observed between age and the total TEQ concentrations of these dioxin-like compounds in the breast milk of primiparae and multiparae. The total TEQ concentrations of PCDDs, PCDFs, and dioxin-like PCBs in the blood of primiparous mothers showed a close correlation to those in their breast milk and also showed good correlations between the total TEQ concentrations of these dioxin-like compounds in the blood of multiparous mothers and those in their breast milk. The result of a comparison of the arithmetic mean concentrations of each congener of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs in blood and breast milk indicated that the transfer of octachlorodibenzo-p-dioxin (OCDD) from the blood to the breast milk was lower than those of other congeners. In contrast, among mono-ortho PCBs congeners, the arithmetic mean concentrations of 2,3',4,4',5-pentachlorobiphenyl (PentaCB) (#118) and 2,3,3',4,4'-PentaCB (#105) in the breast milk were slightly higher than those in the blood, which suggested that breast-fed infants may be at higher risk from mono-ortho PCBs.

Genetic polymorphisms of ESR1 and ESR2 that may influence estrogen activity and the risk of hypospadias

BACKGROUND

The etiology of hypospadias is regarded as a complex disorder with both genetic and environmental contributions. Although alterations in androgen activity have been associated with hypospadias, few associations with estrogen activity have been documented. Here, we assessed genetic polymorphisms in estrogen receptor genes and their association with hypospadias.

METHODS

Using a case-control study of 59 cases with hypospadias and 286 controls, we examined the association of hypospadias with the following polymorphisms: PvuII and XbaI in ESR1, and 2681-4A>G in ESR2.

RESULTS

For the cases, we found a negative association with the G allele containing variants of ESR1 XbaI (OR = 0.52, P < 0.05), and a negative association with the G allele containing variants of ESR2 2681-4A>G (OR = 0.59, P < 0.05). For the cases, we also identified a negative association with the CG haplotype, and a positive association with the CA haplotype, defined by ESR1 PvuII and XbaI (P < 0.05).

CONCLUSIONS

These findings suggest that the G allele containing variants of ESR1 XbaI and the G allele containing variants of ESR2 2681-4A>G may decrease the risk of hypospadias, whereas the ESR1 C-A haplotype may increase its risk.

Adverse birth outcomes associated with maternal smoking and polymorphisms in the N-Nitrosamine-metabolizing enzyme genes NQO1 and CYP2E1

Maternal smoking during pregnancy can result in both pregnancy complications and reduced size of the fetus and neonate. Among women who smoke, genetic susceptibility to tobacco smoke also is a likely causative factor in adverse pregnancy outcomes. A prospective cohort study was conducted among 460 pregnant women who delivered live singletons in Sapporo, Japan, from 2002 to 2005. Multiple linear regression models were used to estimate associations of maternal smoking and polymorphisms in two genes encoding N-nitrosamine-metabolizing enzymes-NAD(P)H: quinone oxidoreductase 1 (NQO1) and cytochrome P-450 2E1 (CYP2E1)-with birth size. Among infants born to smokers with the NQO1 homozygous wild-type allele, birth weight, birth length, and birth head circumference were significantly reduced (p < 0.01 for each factor). For the homozygous wild-type CYP2E1 allele, birth weight was lower by an estimated 195 g (standard error, 55; p < 0.001) among smokers. These genotypes did not confer adverse effects among women who had never smoked or who quit smoking during the first trimester. The adverse effects of maternal smoking on infant birth size may be modified by maternal genetic polymorphisms in N-nitrosamine-metabolizing enzymes among Japanese subjects. These results may help in directing smoking cessation interventions during pregnancy, especially among susceptible women.

Exploiting gene-environment interaction to detect adverse health effects of environmental chemicals on the next generation

There is increasing evidence from epidemiological studies that genetic susceptibilities may modify the teratogenic effects of toxic chemicals. However, in contrast to tobacco smoke, few epidemiological studies have addressed environmental chemicals, such as polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and polychlorinated biphenyls in regard to genetic susceptibility. Recent studies, including the Hokkaido Study of Environments and Children's Health, have investigated the impacts of both environmental and genetic factors on children's development. Several xenobiotic-metabolizing genes have been reported to confer genetic susceptibility to low birth weight. These genes seem to be influenced functionally by maternal smoking during pregnancy, itself a significant risk factor. In our study, we found that birth weight was significantly lower among infants born to smoking women having the specific AHR, CYP1A1, GSTM1, CYP2E1 and NQO1 genotypes. When combinations of these genotypes were considered, birth weight was even lower. On the other hand, congenital anomalies such as hypospadias seemed to be caused by environmental factors in conjunction with genetic predisposition as suggested by linkage in several case-control studies reported to low birth weight. We have found an association between maternal CYP1A1 genotype or low birth weight and the risk of hypospadias irrespective of smoking. At the same time, birth weight was negatively correlated with maternal blood concentrations of polychlorinated dibenzofurans. Further studies should elucidate the impact of genetic factors on adverse effects of exposures to dioxin-related chemicals.

H pylori seropositivity and cytokine gene polymorphisms

AIM: To investigate whether the pro- and anti-inflammatory cytokine gene polymorphisms, IL1B-511C/T, IL1B-31C/T, IL6-634C/G, TNF-1031T/C, TNF-857C/T, and IL10-1082A/G, interact with smoking and drinking habits to influence infection with H pylori.

METHODS: The subjects were 410 Japanese transit company employees. C-reactive protein and conventional cardiovascular risk factors were evaluated. Serum anti-H pylori antibodies were measured. The genotypes of IL1B-511C/T, IL1B-31C/T, IL6-634C/G, TNF-1031T/C, TNF-857C/T, and IL10-1082A/G polymorphisms were determined by allelic discrimination using fluorogenic probes and a 5´nuclease assay.

RESULTS: In gender- and age-adjusted logistic analyses, the subjects with TNF-857T/T had a significantly lower odds ratio (OR) for H pylori seropositivity (reference -857C/C; OR = 0.15, 95%CI: 0.03-0.59, P = 0.007). After stratification according to smoking and drinking status, among never-smokers, the subjects with IL1B-511C/T had a significantly lower OR (reference -511C/C; OR = 0.30, 95%CI: 0.10-0.90, P = 0.032). Among drinkers in the 1-5 times/wk category, the subjects with IL1B-511T/T had a significantly lower OR (reference C/C; OR = 0.38, 95%CI: 0.16-0.95, P = 0.039), and the subjects with IL1B-31C/T and T/T had a significantly higher OR (reference C/C; C/T: OR = 2.59, 95%CI, P = 0.042: 1.04-6.47; C/C: OR = 3.17, 95%CI: 1.23-8.14, P = 0.017). Among current smokers, the subjects with IL6-634C/G had a significantly higher OR (reference C/C; OR = 2.28, 95%CI: 1.13-4.58, P = 0.021). However, the interactions terms between the aforementioned genotypes and lifestyles were not statistically significant.

CONCLUSION: Contrary to previous findings, the results herein suggest that the TNF-857T/T genotype may be protective against chronic infection with H pylori. Drinking and smoking habits may influence the effect of cytokine gene polymorphisms. Further studies are required to clarify the effects of the pro- and anti-inflammatory cytokine polymorphisms and gene-environmental interactions on H pylori infection.

Polycystic ovary syndrome is associated with genetic polymorphism in the insulin signaling gene IRS-1 but not ENPP1 in a Japanese population

Recent studies indicate that insulin resistance resulting from altered post-receptor signaling is associated with polycystic ovary syndrome (PCOS). We hypothesized that insulin receptor substrate-1 (IRS-1) Gly972Arg polymorphism and/or ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) Lys121Gln polymorphism predisposes women to PCOS and that these polymorphisms also affect anthropometric variables, glucose metabolism and androgen synthesis. To test those ideas, we studied the genotypes, indexes of insulin resistance, and hormone profiles in 123 Japanese women with PCOS and 380 healthy Japanese controls. We found that there were significantly more IRS-1 972Arg carriers among the PCOS patients than among the healthy controls (10.6% vs. 4.8%, p=0.029), which is consistent with our finding that women carrying the IRS-1 972Arg allele had a significantly increased risk of developing PCOS (odds ratio: 3.31, 95% confidence interval: 1.49-7.35). By contrast, the ENPP1 Lys121Arg polymorphism was distributed equally among PCOS patients and controls. In addition, neither of these polymorphisms studied affected the anthropometric variables, metabolic parameters or androgen levels of women with PCOS. We conclude that the IRS-1 Gly972Arg polymorphism is associated with PCOS in the Japanese population.

Cognitive brain function after hypothermic circulatory arrest assessed by cognitive P300 evoked potentials

BACKGROUND

The role of hypothermic circulatory arrest (HCA) in cardiovascular surgery is controversial and assumed to result in neurocognitive dysfunction that is not always detected by standard clinical observation. We assessed cognitive P300 visual evoked potentials (P300) in patients undergoing either HCA or coronary artery bypass grafting (CABG) to elucidate whether HCA was associated with postoperative cognitive decline.

METHODS

Thirteen patients undergoing either aortic arch replacement (n=4) or pulmonary thromboendarterectomy (n=9) using HCA (mean: 28+/-11 min, 22+/-2 degrees C) were studied. They were compared to 13 patients undergoing on-pump CABG. P300s were measured 1 day before and 1 week after the operation. We assessed an area under the curve (AUC) between 280 and 600 ms and center of this area [Ct (time), Cv (voltage)]. The ratio of these parameters acquired by target (TG) and non-target (NTG) stimulus (TG/NTG) was calculated to assess concentration on TG stimulus and defined as concentration index (CI: CI(AUC), CI(Ct), and CI(Cv)).

RESULTS

There was no significant difference in preoperative characteristics between groups. There were neither strokes nor hospital deaths. Preoperatively, the HCA group could not concentrate on target stimulus as well as the control group in frontal leads (CI(AUC) and CI(Cv) were lower in HCA group than in control group). However, the HCA group could concentrate on target stimulus better than the control group postoperatively because postoperative CI(AUC) (pre-operation: 1.1+/-0.5 to post-operation: 1.7+/-0.4, P=.02) and CI(Cv) (1.1+/-0.4 to 1.6+/-0.4, P=.01) were significantly improved in the HCA group, whereas these were significantly impaired in the control group (CI(AUC): 1.6+/-0.6 to 1.3+/-0.4, P=.03, CI(Cv): 1.5+/-0.5 to 1.2+/-0.3, P<.01). Postoperative CI(Ct) in the HCA group were significantly impaired in all leads. The duration of HCA did not correlate with any values of postoperative P300. No specific trends were observed in either preoperative or postoperative P300 values between patients with or without postoperative temporary neurological dysfunction (one in each group). Postoperative improvement of CI(AUC) and CI(Cv) in Fz lead were found in 85 and 69% in the HCA group and 23 and 23% in the control group, respectively (CI(AUC): P<.01, CI(Cv): P<.05).

CONCLUSIONS

P300 detected no significant neurocognitive impairment due to the relatively brief period of HCA (approximately 28 min).

Functional maternal catechol-O-methyltransferase polymorphism and fetal growth restriction

OBJECTIVES

The pathophysiologic processes that occur at the cellular and molecular levels in intrauterine fetal growth restriction are largely unknown. Catechol-O-methyltransferase (COMT) is a phase II enzyme that inactivates catechol estrogens by transfer of a methyl group. A functional Val158Met polymorphism in the COMT gene has been known as a susceptible marker for breast cancer. The aim of this study was to examine the association between this polymorphism and fetal growth.

METHODS

A consecutive series of 412 women who experienced singleton deliveries was assessed in the birth cohort study. Genotyping of COMT and CYP17A1 polymorphisms was determined by allelic discrimination using fluorogenic probes and the 5'nuclease assay.

RESULTS

The adjusted odds ratio for the risk of low birth weight (<2.500 g) in women with homozygous low-activity (COMT-L) alleles was 2.98 (95% confidence interval, 1.10-8.11). The mean birth weight of infants whose mothers were homozygous for COMT-L was less than that of infants whose mothers had at least one high-activity (COMT-H) allele (2.610 versus 2.800 g, P=0.07). The odds ratio for the risk of intrauterine fetal growth restriction, defined as birth weight <10th percentile or <mean-1.5 SD, in women homozygous for COMT-L alleles was 2.63/2.57 (95% confidence interval, 1.14-6.05/0.96-6.88). In the recessive genotype model, the odds ratios for the risk of low birth weight and intrauterine fetal growth restriction in women homozygous for COMT-L were 3.36 (95% confidence interval, 1.30-8.65) and 2.89/2.65 (95% confidence interval, 1.31-6.34/1.06-6.65), respectively. A positive association exists between birth weight and the homozygous CYP17A1 A2 genotype (P<0.01). When both COMT and CYP17A1 genotypes were considered, the highest risk of low birth weight/intrauterine fetal growth restriction was found among women with the homozygous COMT-L and CYP17A1 A1 genotype. The odds ratio for the risk of intrauterine fetal growth restriction (<10th percentile) in those women was 5.35 (95% confidence interval, 1.15-25.0).

CONCLUSION

Our findings suggest that the allele encoding low-activity COMT may be a susceptible marker for intrauterine fetal growth restriction.

Effects of the Interaction between Interleukin-6-634C/G Polymorphism and Smoking on Serum C-Reactive Protein Concentrations

Smoking and interleukin-6 (IL-6) are major factors in inflammation. The aim of this study was to investigate whether or not the IL6 -634C/G polymorphism (rs1800796) and its interaction with smoking influence serum C-reactive protein (CRP) concentrations. The subjects were 347 Japanese male employees of a transit company. CRP and conventional cardiovascular risk factors were evaluated. IL6 -634C/G polymorphisms were genotyped by allelic discrimination using fluorogenic probes and the 5' nuclease assay. The mean values of CRP were significantly higher in current smokers than in nonsmokers after adjustment for age, body mass index (BMI), systolic blood pressure, total cholesterol, log triglycerides, high-density lipoprotein cholesterol (HDL-C), fasting glucose, and drinking habit (p=0.011). Comparison of three genotypes revealed significant interaction between smoking and the IL6 -634C/G genotype manifested by CRP concentrations (p=0.007) after the adjustments cited above. After stratification by smoking status, CRP differed significantly among IL6 -634C/G genotypes groups in nonsmokers (p=0.010, p for trend=0.007), whereas no significant difference was found in current smokers. Comparison between -634C/C and C/G+G/G groups revealed also a significant interaction between smoking and the IL6 -634C/G genotype (p=0.007). These findings suggest that the impact of the -634G allele on CRP elevation is greater in nonsmokers than in current smokers. Since gene-environment interactions have been insufficiently examined, further studies are required to clarify their effect on inflammation, including CRP elevation.

Pregnancy-associated plasma protein-A polymorphism and the risk of recurrent pregnancy loss

Pregnancy-associated plasma protein-A (PAPP-A)/insulin-like growth factor-binding protein-4 (IGFBP4) protease is a member of the metzincin family of metalloproteases, known as a sensitive biomarker of adverse pregnancy outcomes. Recently, a missense A/C (Tyr/Ser) polymorphism (dbSNP: rs7020782) in the PAPPA gene has been reported. To examine the association between recurrent pregnancy loss (RPL) and this polymorphism, a case-control study of 215 cases with two or more pregnancy losses (PLs) and 420 fertile controls was performed. Genotyping of the PAPPA polymorphism was determined by allelic discrimination using fluorogenic probes and the 5' nuclease assay. Sixty-nine cases (32.1%) were heterozygous and 11 cases (5.1%) were homozygous for the C allele of PAPPA; the respective figures were 127 (30.2%) and 11 (2.6%) in the controls. Women carrying the C allele had a tendency to increased risk of RPL (AA genotype [reference]; AC genotype: odds ratio [OR], 1.17; 95% confidence interval [CI], 0.82-1.68; CC genotype: OR, 2.06; 95% CI, 0.87-4.90), but it was not significant. Women with three or more PLs had a similar tendency (AA genotype [reference]; AC genotype: OR, 1.04; 95% CI, 0.66-1.64; CC genotype: OR, 2.20; 95% CI, 0.82-5.91). The risk of RPL with at least one PL after 9 weeks' gestation significantly increased in women carrying the C allele (AA genotype [reference]; AC genotype: OR, 1.54; 95% CI, 0.95-2.49; CC genotype: OR, 2.83; 95% CI, 1.00-8.05; AC+CC genotypes: OR, 1.65; CI, 1.04-2.62). This is the first report on the PAPPA gene polymorphism in women with RPL, demonstrating some association between the investigated polymorphism and the risk of RPL.

[Exposure to endocrine disrupting chemicals and children's health: problems in epidemiological studies]

Most endocrine disrupting chemicals are characterized by their properties to induce marked phenotypic changes in offspring such as congenital anomalies and neurodevelopmental dysfunctions. Although an increase in the prevalence of hypospadias or cryptorchidism has been reported in various countries, improvement in diagnostic techniques and more attention to the features of the diseases have also been emphasized. Although there have been a few reports that hypospadias or cryptorchidism had been associated with diethylstilbestrol (DES), pesticides and so on, the associations between these diseases and endocrine disrupting chemicals remain unclear. Recently, the association between maternal metabolic polymorphism or paternal smoking during pregnancy and these diseases has been reported. There are also variable clinical features in children's neurobehavioral development, and thyroid and immune functions in relation to exposure to endocrine disrupting chemicals such as polychlorinated biphenyls (PCBs) and dioxins. Only a few Dutch studies have suggested that perinatal exposure to background level of PCB/dioxin confers immunity to allergy development. Genetic susceptibility to environmental endocrine disrupting chemicals may be related to adverse pregnancy outcomes. It is suggested that well-designed epidemiological studies such as prospective cohort studies should be performed to elucidate this association.

Effects of prenatal exposure to polychlorinated biphenyls and dioxins on mental and motor development in Japanese children at 6 months of age

Several studies have shown that prenatal and/or postnatal background-level exposure to environmental chemicals, such as polychlorinated biphenyls (PCBs) and dioxins, induces adverse effects on the neurodevelopment of children. However, other studies have not detected any harmful influences on neurodevelopment. Furthermore, except in western countries, no developmental tests have been carried out in relation to detailed assessment of exposure to PCBs and dioxins. In this study (the Hokkaido Study on Environment and Children's Health), the effect of prenatal exposure to background levels of PCBs and dioxins on infant neurodevelopment in Japan/Sapporo was elucidated. The associations between the total or individual isomer level of PCBs and dioxins in 134 Japanese pregnant women's peripheral blood and the mental or motor development of their 6-month-old infants were evaluated using the second edition of the Bayley Scales of Infant Development. The mean level of total toxicity equivalency quantity (TEQ) was 18.8 (4.0-51.2) pg/g lipid in blood of 134 mothers. After adjustment for potential confounding variables, the total TEQ value was shown not to be significantly associated with mental developmental index (MDI) or psychomotor developmental index (PDI). However, the levels of one polychlorinated dibenzo-p-dioxin (PCDD) isomer, total PCDDs, and total PCDDs/polychlorinated dibenzofurans (PCDFs) were significantly negatively associated with MDI, and the levels of two PCDD isomers and three PCDF isomers were significantly negatively associated with the PDI. In conclusion, the background-level exposure of several isomers of dioxins during the prenatal period probably affects the motor development of 6-month-old infants more than it does their mental development.

Maternal smoking during pregnancy and genetic polymorphisms in the Ah receptor, CYP1A1 and GSTM1 affect infant birth size in Japanese subjects

Genetic susceptibility to tobacco smoke might have relation to adverse pregnancy outcomes. To estimate the effects of maternal smoking and genetic polymorphisms on infant birth weight and length, we conducted a prospective cohort study of 293 women who delivered singleton live births in Sapporo, Japan. Birth weight and length were significantly lower among infants born to continuously smoking women having the aryl hydrocarbon receptor (AhR) wild type genotype (Arg/Arg; 211 g +/- 76 g; 1.2 cm +/- 0.4 cm, p < 0.01 and p < 0.01, respectively), the CYP1A1 variant genotype (m1/m2 + m2/m2; 170 g +/- 64 g, 0.8 cm +/- 0.3 cm, p < 0.01 and p < 0.05, respectively), or the GSTM1 null genotype (171 g +/- 58 g, 0.6 cm +/- 0.3 cm, p < 0.01 and p < 0.05, respectively). When combinations of these genotypes were considered, birth weight and length were significantly lower for infants of continuously smoking women in the AhR wild type + CYP1A1 variant group (315 g +/- 116 g; 1.7 cm +/- 0.6 cm, p < 0.01 and p < 0.01, respectively) and in the CYP1A1 variant + GSTM1 null group (237 g +/- 92 g; 1.3 cm +/- 0.5 cm, p < 0.05 and p < 0.01, respectively). These genotypes did not confer adverse effects among women who had never smoked; therefore, maternal smoking in combination with maternal AhR, CYP1A1 and GSTM1 genetic polymorphisms may adversely affect infant birth size.

Long-term results of treatments for varicose veins due to greater saphenous vein insufficiency

AIM

The purpose of this study was to determine the long-term recurrence rates of greater saphenous vein (GSV) insufficiency after treatments for primary varicose veins, and to elucidate risk factors for recurrence.

METHODS

This was a multicenter retrospective analysis of 376 limbs of 296 patients treated for primary varicose veins due to GSV insufficiency from January 1996 to December 1997. The recurrence-free rates after stripping surgery, saphenofemoral ligation, and sclerotherapy were estimated. The risk factors for the recurrence of primary varicose veins were estimated by multiple regression analysis.

RESULTS

The follow-up period was 3.1+/-1.3 (mean+/-SD) years. The recurrence-free rates at 4 years after stripping, saphenofemoral ligation and sclerotherapy were 80.7%, 64.5%, and 51.3%, respectively. The saphenofemoral ligation group and sclerotherapy group had significantly higher recurrence rates than the stripping group (P=0.002, P<0.001, respectively). There was no difference in recurrence rates between the saphenofemoral ligation group and sclerotherapy group (P=0.074). Logistic regression analysis revealed that being female (P<0.029) and treatment without stripping (P<0.001) increased the recurrence rate.

CONCLUSIONS

Stripping surgery may be the treatment of first choice for patients with varicose veins due to GSV insufficiency. Patients who have not received stripping surgery and female patients require closer follow-up.