Polychlorinated Biphenyls (PCBs) and Sex Hormone Concentrations in Ringed and Grey Seals: A Possible Link to Endocrine Disruption?

Polychlorinated biphenyls (PCBs) are recognised reproductive and immune system toxicants in marine mammals mediated by endocrine-disrupting mechanisms. As with other predators, seals are exposed to elevated bioaccumulated concentrations of PCBs and other persistent organic pollutants (POPs). Cryopreserved plasma samples from adult ringed (Phoca hispida; n = 39) and grey (Halichoerus grypus; n = 38) seals, sampled between 1998 and 2002 from Baltic Sea, Svalbard, and Sable Island (Canada) were used to investigate relationships between PCB exposure and sex hormone concentrations (progesterone; P4, 17α-hydroxy progesterone; 17α-OH-P4, testosterone; T4, 17ß-estradiol; E2, estrone; E3). Immunoassay methods were used for quantification of analytes due to the limited sample volumes available. PCB concentrations were found to be significantly higher in Baltic seals than other sampling locations and were classed as "Exposed" seals while Svalbard and Sable Is seal were classed "Reference" seals (sexes and species separate). Mean hormone concentrations in Exposed seal were lower than Reference seals, and this was statistically significantly for 17α-OH-P4 (both sexes and both species), E2 (ringed and grey seal females), and E3 (grey seal females). Regression analyses (PCB v hormone concentrations) for each sex and species revealed significant correlations for P4 (Sable Is. female grey seals and female ringed seals), 17α-OH-P4 (Sable Is. male grey seals and Svalbard male ringed seals), T4 (Svalbard male ringed seals), E2 (female ringed seals), and E3 (female ringed seals and Baltic female grey seals). Although significant correlations are not evidence of cause and effect, the potential impact of hormone changes on endocrine homeostasis and reproductive health for seal populations warrants further investigation given that PCB concentrations found here are in the same range as those currently reported in seals from these populations.

Maternal and fetal genetic contribution to gestational weight gain.

BACKGROUND: Clinical recommendations to limit gestational weight gain (GWG) imply high GWG is causally related to adverse outcomes in mother or offspring, but GWG is the sum of several inter-related complex phenotypes (maternal fat deposition and vascular expansion, placenta, amniotic fluid and fetal growth). Understanding the genetic contribution to GWG could help clarify the potential effect of its different components on maternal and offspring health. Here we explore the genetic contribution to total, early and late GWG. PARTICIPANTS AND METHODS: A genome-wide association study was used to identify maternal and fetal variants contributing to GWG in up to 10 543 mothers and 16 317 offspring of European origin, with replication in 10 660 mothers and 7561 offspring. Additional analyses determined the proportion of variability in GWG from maternal and fetal common genetic variants and the overlap of established genome-wide significant variants for phenotypes relevant to GWG (for example, maternal body mass index (BMI) and glucose, birth weight). RESULTS: Approximately 20% of the variability in GWG was tagged by common maternal genetic variants, and the fetal genome made a surprisingly minor contribution to explain variation in GWG. Variants near the pregnancy-specific beta-1 glycoprotein 5 (PSG5) gene reached genome-wide significance (P=1.71 × 10-8) for total GWG in the offspring genome, but did not replicate. Some established variants associated with increased BMI, fasting glucose and type 2 diabetes were associated with lower early, and higher later GWG. Maternal variants related to higher systolic blood pressure were related to lower late GWG. Established maternal and fetal birth weight variants were largely unrelated to GWG. CONCLUSIONS: We found a modest contribution of maternal common variants to GWG and some overlap of maternal BMI, glucose and type 2 diabetes variants with GWG. These findings suggest that associations between GWG and later offspring/maternal outcomes may be due to the relationship of maternal BMI and diabetes with GWG.

DNA methylation of Th2 lineage determination genes at birth is associated with allergic outcomes in childhood.

BACKGROUND: There is now increasing evidence that asthma and atopy originate in part in utero, with disease risk being associated with the altered epigenetic regulation of genes. OBJECTIVE AND METHODS: To determine the relationship between variations in DNA methylation at birth and the development of allergic disease, we examined the methylation status of CpG loci within the promoter regions of Th1/2 lineage commitment genes (GATA3, IL-4, IL-4R, STAT4 and TBET) in umbilical cord DNA at birth in a cohort of infants from the Southampton Women's Survey (n = 696) who were later assessed for asthma, atopic eczema and atopy. RESULTS: We found that higher methylation of GATA3 CpGs -2211/-2209 at birth was associated with a reduced risk of asthma at ages 3 (median ratio [median methylation in asthma group/median methylation in non-asthma group] = 0.74, P = .006) and 6-7 (median ratio 0.90, P = .048) years. Furthermore, we demonstrated that the GATA3 CpG loci associated with later risk of asthma lie within a NF-κB binding site and that methylation here blocks transcription factor binding to the GATA3 promoter in the human Jurkat T-cell line. Associations between umbilical cord methylation of CpG loci within IL-4R with atopic eczema at 12 months (median ratio 1.02, P = .028), and TBET with atopy (median ratio 0.98, P = .017) at 6-7 years of age were also observed. CONCLUSIONS AND CLINICAL RELEVANCE: Our findings provide further evidence of a developmental contribution to the risk of later allergic disorders and suggest that involvement of epigenetic mechanisms in childhood asthma is already demonstrable at birth.

Placental amino acid transport may be regulated by maternal vitamin D and vitamin D-binding protein: results from the Southampton Women's Survey.

Both maternal 25-hydroxyvitamin D (25(OH)D) concentrations during pregnancy and placental amino acid transporter gene expression have been associated with development of the offspring in terms of body composition and bone structure. Several amino acid transporter genes have vitamin D response elements in their promoters suggesting the possible linkage of these two mechanisms. We aimed to establish whether maternal 25(OH)D and vitamin D-binding protein (VDBP) levels relate to expression of placental amino acid transporters. RNA was extracted from 102 placental samples collected in the Southampton Women's Survey, and gene expression was analysed using quantitative real-time PCR. Gene expression data were normalised to the geometric mean of three housekeeping genes, and related to maternal factors and childhood body composition. Maternal serum 25(OH)D and VDBP levels were measured by radioimmunoassay. Maternal 25(OH)D and VDBP levels were positively associated with placental expression of specific genes involved in amino acid transport. Maternal 25(OH)D and VDBP concentrations were correlated with the expression of specific placental amino acid transporters, and thus may be involved in the regulation of amino acid transfer to the fetus. The positive correlation of VDBP levels and placental transporter expression suggests that delivery of vitamin D to the placenta may be important. This exploratory study identifies placental amino acid transporters which may be altered in response to modifiable maternal factors and provides a basis for further studies.

Alpha-tryptase gene variation is associated with levels of circulating IgE and lung function in asthma.

BACKGROUND: Tryptase, a major secretory product of human mast cells has been implicated as a key mediator of allergic inflammation. Genetic variation in the tryptases is extensive, and α-tryptase, an allelic variant of the more extensively studied ß-tryptase, is absent in substantial numbers of the general population. The degree to which α-tryptase expression may be associated with asthma has not been studied. We have investigated the α-tryptase gene copy number variation and its potential associations with phenotypes of asthma. OBJECTIVES: Caucasian families (n = 341) with at least two asthmatic siblings (n = 1350) were genotyped for the α-tryptase alleles, using high-resolution melting assays. Standards for the possible α-/ß-tryptase ratios were constructed by cloning α-and ß-tryptase PCR products to generate artificial templates. Association analysis of asthma affection status and related phenotypes [total and allergen-specific serum IgE, bronchial hyperresponsiveness to methacholine, forced expiratory volume in 1s (FEV1 ) and atopy and asthma severity scores] was undertaken using family-based association tests (FBAT). RESULTS: Four consistent melting patterns for the α-tryptase genotype were identified with alleles carrying null, one or two copies of the α-tryptase allele. Possessing one copy of α-tryptase was significantly associated with lower serum levels of total and dust mite-specific IgE levels and higher FEV1 measurements, while two copies were related to higher serum concentrations of total and dust mite-specific IgE and greater atopy severity scores. CONCLUSIONS AND CLINICAL RELEVANCE: Associations of α-tryptase copy number with serum IgE levels, atopy scores and bronchial function may reflect roles for tryptases in regulating IgE production and other processes in asthma.

DNA methylation signatures in cord blood associated with birthweight are enriched for dmCpGs previously associated with maternal hypertension or pre-eclampsia, smoking and folic acid intake.

Many epidemiological studies have linked low birthweight to an increased risk of non-communicable diseases (NCDs) in later life, with epigenetic proceseses suggested as an underlying mechanism. Here, we sought to identify neonatal methylation changes associated with birthweight, at the individual CpG and genomic regional level, and whether the birthweight-associated methylation signatures were associated with specific maternal factors. Using the Illumina Human Methylation EPIC array, we assessed DNA methylation in the cord blood of 557 and 483 infants from the UK Pregnancies Better Eating and Activity Trial and Southampton Women's Survey, respectively. Adjusting for gestational age and other covariates, an epigenome-wide association study identified 2911 (FDR≤0.05) and 236 (Bonferroni corrected p ≤ 6.45×10-8) differentially methylated CpGs (dmCpGs), and 1230 differentially methylated regions (DMRs) (Stouffer ≤0.05) associated with birthweight. The top birthweight-associated dmCpG was located within the Homeobox Telomere-Binding Protein 1 (HMBOX1) gene with a 195 g (95%CI: -241, -149 g) decrease in birthweight per 10% increase in methylation, while the top DMR was located within the promoter of corticotropin-releasing hormone-binding protein (CRHBP). Furthermore, the birthweight-related dmCpGs were enriched for dmCpGs previously associated with gestational hypertension/pre-eclampsia (14.51%, p = 1.37×10-255), maternal smoking (7.71%, p = 1.50 x 10-57) and maternal plasma folate levels during pregnancy (0.33%, p = 0.029). The identification of birthweight-associated methylation markers, particularly those connected to specific pregnancy complications and exposures, may provide insights into the developmental pathways that affect birthweight and suggest surrogate markers to identify adverse prenatal exposures for stratifying for individuals at risk of later NCDs.

Up-regulation of GLT1 expression increases glutamate uptake and attenuates the Huntington's disease phenotype in the R6/2 mouse.

The striatum, which processes cortical information for behavioral output, is a key target of Huntington's disease (HD), an autosomal dominant condition characterized by cognitive decline and progressive loss of motor control. Increasing evidence implicates deficient glutamate uptake caused by a down-regulation of GLT1, the primary astroglial glutamate transporter. To test this hypothesis, we administered ceftriaxone, a beta-lactam antibiotic known to elevate GLT1 expression (200 mg/kg, i.p., for 5 days), to symptomatic R6/2 mice, a widely studied transgenic model of HD. Relative to vehicle, ceftriaxone attenuated several HD behavioral signs: paw clasping and twitching were reduced, while motor flexibility, as measured in a plus maze, and open-field climbing were increased. Assessment of GLT1 expression in striatum confirmed a ceftriaxone-induced increase relative to vehicle. To determine if the change in behavior and GLT1 expression represented a change in striatal glutamate handling, separate groups of behaving mice were evaluated with no-net-flux microdialysis. Vehicle treatment revealed a glutamate uptake deficit in R6/2 mice relative to wild-type controls that was reversed by ceftriaxone. Vehicle-treated animals, however, did not differ in GLT1 expression, suggesting that the glutamate uptake deficit in R6/2 mice reflects dysfunctional rather than missing GLT1. Our results indicate that impaired glutamate uptake is a major factor underlying HD pathophysiology and symptomology. The glutamate uptake deficit, moreover, is present in symptomatic HD mice and reversal of this deficit by up-regulating the functional expression of GLT1 with ceftriaxone attenuates the HD phenotype.

The role of LTA4H and ALOX5AP polymorphism in asthma and allergy susceptibility.

BACKGROUND: Leukotrienes (LTs) have been identified as central mediators in asthma and allergy. Pharmacological inhibition of cysteinyl-LT activity improves asthma symptoms and control. Accumulating evidence suggests a role for the dihydroxy leukotriene LTB(4) in airway disease. LTA(4) hydrolase and 5-lipoxygenase activating protein have key roles in LTB(4) production. Single nucleotide polymorphism (SNPs) and haplotypes spanning the LTA4H and ALOX5AP genes have been associated with LTB(4) production and myocardial infarction (MI). OBJECTIVE: To assess the contribution of LTA4H and ALOX5AP polymorphism to asthma and allergy susceptibility. METHODS: Three hundred and forty-one Caucasian families (two asthmatic siblings) were genotyped for eight SNPs spanning ALOX5AP and five SNPs spanning LTA4H. Association analyses of asthma and related phenotypes (total IgE, atopy, bronchial hyper-responsiveness, FEV(1)) were undertaken using the Family Based Association Test. RESULTS: Single point analyses identified association (P < 0.05) between SNPs SG13S114, SG13S89, SG13S41 (ALOX5AP), rs1978331 (LTA4H) and asthma and/or related phenotypes. Haplotype analyses using all LTA4H SNPs identified a single key risk haplotype for the development of asthma (P = 0.006) and related phenotypes (P = 0.042-0.005). Haplotype analyses using all ALOX5AP SNPs identified several asthma and atopy risk and protective haplotypes. There was limited correlation with previously identified MI risk haplotypes in both genes. Carriers of both ALOX5AP SG13S41 and LTA4H rs1978331 alleles had an increased risk of developing asthma (OR 2.17, CI 1.41-3.32). CONCLUSIONS: These data provide evidence for the role of SNPs spanning the ALOX5AP and LTA4H genes in asthma and atopy susceptibility in the Caucasian population and support a role for LTB(4) in disease pathogenesis.

Hyperactive striatal neurons in symptomatic Huntington R6/2 mice: variations with behavioral state and repeated ascorbate treatment.

Membrane and morphological abnormalities occur in the striatum of R6/2 transgenics, a widely used mouse model of Huntington's disease. To assess changes in behavior-related neuronal activity, we implanted micro-wire bundles in the striatum of symptomatic R6/2 mice and wild-type controls. Unit activity was recorded in an open-field arena once weekly for the next several weeks. For each recording session, firing rate was monitored before, during, and after a period of light anesthesia to assess the influence of behavioral arousal. Because low ascorbate in striatal extracellular fluid may contribute to Huntington's disease symptoms, all animals received an injection of either 300 mg/kg sodium ascorbate or vehicle for three consecutive days prior to each recording session. In R6/2 mice, regardless of treatment, striatal unit activity was significantly faster than in wild-type controls. The difference in mean (+/-S.E.M.) firing was most apparent during wakefulness (6.4+/-0.8 vs. 3.5+/-0.3 spikes/s) but also persisted during anesthesia (2.0+/-0.3 vs. 0.7+/-0.1 spikes/s). Assessment of treatment duration indicated that R6/2 mean waking discharge rate was significantly slower after three weeks than after one week of ascorbate treatment (3.1+/-0.6 vs. 10.2+/-2.7 spikes/s). Vehicle-treated R6/2s showed no such decline in striatal activity ruling out an age- or injection-related effect. Slow-scan voltammetry in separate animals confirmed that ascorbate-injections returned the level of striatal extracellular ascorbate in R6/2 mice to that of wild-type controls. Our results indicate that although striatal neurons modulate firing in relation to behavioral state, impulse activity is consistently elevated in transgenic relative to wild-type mice. Restoring extracellular ascorbate to the wild-type level reverses this effect suggesting a role for ascorbate in normalizing neuronal function in Huntington's disease striatum.

Relation of FTO gene variants to fetal growth trajectories: Findings from the Southampton Women's survey.

INTRODUCTION: Placental function is an important determinant of fetal growth, and fetal growth influences obesity risk in childhood and adult life. Here we investigated how FTO and MC4R gene variants linked with obesity relate to patterns of fetal growth and to placental FTO expression. METHODS: Southampton Women's Survey children (n = 1990) with measurements of fetal growth from 11 to 34 weeks gestation were genotyped for common gene variants in FTO (rs9939609, rs1421085) and MC4R (rs17782313). Linear mixed-effect models were used to analyse relations of gene variants with fetal growth. RESULTS: Fetuses with the rs9939609 A:A FTO genotype had faster biparietal diameter and head circumference growth velocities between 11 and 34 weeks gestation (by 0.012 (95% CI 0.005 to 0.019) and 0.008 (0.002-0.015) standard deviations per week, respectively) compared to fetuses with the T:T FTO genotype; abdominal circumference growth velocity did not differ between genotypes. FTO genotype was not associated with placental FTO expression, but higher placental FTO expression was independently associated with larger fetal size and higher placental ASCT2, EAAT2 and y + LAT2 amino acid transporter expression. Findings were similar for FTO rs1421085, and the MC4R gene variant was associated with the fetal growth velocity of head circumference. DISCUSSION: FTO gene variants are known to associate with obesity but this is the first time that the risk alleles and placental FTO expression have been linked with fetal growth trajectories. The lack of an association between FTO genotype and placental FTO expression adds to emerging evidence of complex biology underlying the association between FTO genotype and obesity.

An unusual presentation of metastatic testicular tumour.

We report a unique case of metastatic malignant teratoma from an undescended testis which presented with acute pulmonary embolism. After chemotherapy, the undescended right testicle was resected along with a cord of non- obstructing inferior venal caval tumour which extended into the right atrium with tumour floating free within the atrium at the end of the cord of tumour. The presentation, diagnosis and treatment of testicular tumours is described and the literature pertaining to testicular tumours in military personnel reviewed.

Genome-wide methylation analysis identifies differentially methylated CpG loci associated with severe obesity in childhood.

Childhood obesity is a major public health issue. Here we investigated whether differential DNA methylation was associated with childhood obesity. We studied DNA methylation profiles in whole blood from 78 obese children (mean BMI Z-score: 2.6) and 71 age- and sex-matched controls (mean BMI Z-score: 0.1). DNA samples from obese and control groups were pooled and analyzed using the Infinium HumanMethylation450 BeadChip array. Comparison of the methylation profiles between obese and control subjects revealed 129 differentially methylated CpG (DMCpG) loci associated with 80 unique genes that had a greater than 10% difference in methylation (P-value < 0.05). The top pathways enriched among the DMCpGs included developmental processes, immune system regulation, regulation of cell signaling, and small GTPase-mediated signal transduction. The associations between the methylation of selected DMCpGs with childhood obesity were validated using sodium bisulfite pyrosequencing across loci within the FYN, PIWIL4, and TAOK3 genes in individual subjects. Three CpG loci within FYN were hypermethylated in obese individuals (all P < 0.01), while obesity was associated with lower methylation of CpG loci within PIWIL4 (P = 0.003) and TAOK3 (P = 0.001). After building logistic regression models, we determined that a 1% increase in methylation in TAOK3, multiplicatively decreased the odds of being obese by 0.91 (95% CI: 0.86 - 0.97), and an increase of 1% methylation in FYN CpG3, multiplicatively increased the odds of being obese by 1.03 (95% CI: 0.99 - 1.07). In conclusion, these findings provide evidence that childhood obesity is associated with specific DNA methylation changes in whole blood, which may have utility as biomarkers of obesity risk.

Nuclear magnetic resonance spectroscopy of cancer.

Nuclear magnetic resonance spectroscopy (MRS) offers a non-invasive approach for studying tumour biochemistry and physiology. This review highlights NMR nuclei (31P, 1H, 19F, 13C, 2H) that have been observed in both pre-clinical and clinical spectroscopic studies of cancer.

Prenatal cocaine exposure: implications for practice, policy development, and needs for future research.

Terms such as coke babies and crack babies are appearing with increased frequency in the popular literature. Although the number of babies exposed to cocaine in utero has increased, synthesis of the literature to help determine the manifestations of cocaine exposure or to direct research on the problems experienced by cocaine-exposed infants and their care givers has yet to occur. In this analysis a synthesis of the literature related to the effects of perinatal cocaine exposure is provided. The manifestations, effects, and sequelae of cocaine exposure are explicated and a model is proposed to explain the mechanisms underlying physiologic and psychosocial expressions of exposure. Both time of exposure during gestation and dose relationships were identified as major predictor variables. Recommendations include the need for (1) an individualized intervention protocol and (2) prevention programs directed at pregnant women and women of childbearing age.

Infant feeding practices of low-income rural mothers.

PURPOSE: To examine infant feeding practices at 1 to 2 months of age and at 4 to 6 months in a rural population of infants at risk for failure to thrive. DESIGN: A descriptive/exploratory study with 52 mothers who were interviewed twice during the infant's first 6 months of life. Mothers were recruited from health care facilities in rural southeastern Kentucky. Mothers participated in two structured interviews about feeding practices conducted in health care clinics or in the home. RESULTS: At birth 52% of mothers chose to use formula, 41.2% chose breastfeeding, and 8% were both breastfeeding and formula feeding. By 1 month, 71% of mothers were formula feeding and only 29% were breastfeeding. At 4 to 6 months postpartum 80% of mothers were formula feeding and 20% were breastfeeding. Mothers with more children, higher family income, and more education were more likely to breastfeed. Almost all mothers began solid foods before the infant was 4 months old. Infants were fed table foods including mashed potatoes and gravy, and beverages such as apple juice, fruit juices, and soda. Mothers relied on health professionals for support for feeding decisions at the first interview; however, they relied more on the grandmother for support at the time of the second interview. CONCLUSIONS AND CLINICAL IMPLICATIONS: Breastfeeding mothers need additional support to continue breastfeeding beyond the first month. Mothers and grandmothers need education to discourage the practice of early introduction of inappropriate solid foods, including the practice of thickening bottles of formula with cereal. Nutrition teaching should be provided to mothers and grandmothers including how to select high nutrient, lower fat-weaning foods, and limiting infant intake of high-calorie drinks.

Promoting family-centered care with foster families.

There has been a tremendous increase in the need for foster families since the 1980s largely because of the effects of drug abuse on the child and the biological family. As many as 500,000 children are currently living with foster families. Many children living with foster families were exposed to drugs before birth. Even those not exposed before birth demonstrate the effects of having lived with drug-abusing family members. Family life for these children is very often chaotic and unpredictable. There are increased health care needs for foster children due to drug-exposure and neglect. Yet, research suggests that the health care needs of foster children are often neglected. Foster families report that their concerns and needs are, frequently, neither recognized nor addressed by health professionals. Pediatric nurses can improve health care by increasing their awareness of the special needs of foster families and foster children.

A comparison of reagent strips and the refractometer for measurement of urine specific gravity in hospitalized children.

Pediatric nurses in acute care settings routinely test urine for specific gravity, pH, glucose, protein, and other substances. In one tertiary care facility, nurses used the refractometer to test urine specific gravity and the reagent strip to test for other substances. This study was designed to provide data to determine if the reagent strip and the refractometer were interchangeable for measuring urine specific gravity in pediatric clients. Nurses obtained urine for specific gravity testing in 157 pediatric patients ranging in age from 1 day to 16 years. Each urine specimen was tested twice, once using the refractometer and once with the reagent strip. A Bland-Altman plot was used to determine the extent of agreement between the two measurement methods. The plot showed strong agreement between the two methods across a wide range of values for urine specific gravity. As a result of this study, staff nurses decided to use the reagent strip for urine specific gravity when other urine tests are needed and to use the refractometer when only a specific gravity is needed. This decision has resulted in a time savings for nurses who now do not have to repeat a reagent strip measurement. The decision also resulted in a savings of approximately $1200 in purchase of new refractometers for a newly constructed unit.