Interpreting biomonitoring data: Introducing the international human biomonitoring (i-HBM) working group's health-based guidance value (HB2GV) dashboard

Human biomonitoring (HBM) data measured in specific contexts or populations provide information for comparing population exposures. There are numerous health-based biomonitoring guidance values, but to locate these values, interested parties need to seek them out individually from publications, governmental reports, websites and other sources. Until now, there has been no central, international repository for this information. Thus, a tool is needed to help researchers, public health professionals, risk assessors, and regulatory decision makers to quickly locate relevant values on numerous environmental chemicals. A free, on-line repository for international health-based guidance values to facilitate the interpretation of HBM data is now available. The repository is referred to as the "Human Biomonitoring Health-Based Guidance Value (HB2GV) Dashboard". The Dashboard represents the efforts of the International Human Biomonitoring Working Group (i-HBM), affiliated with the International Society of Exposure Science. The i-HBM's mission is to promote the use of population-level HBM data to inform public health decision-making by developing harmonized resources to facilitate the interpretation of HBM data in a health-based context. This paper describes the methods used to compile the human biomonitoring health-based guidance values, how the values can be accessed and used, and caveats with using the Dashboard for interpreting HBM data. To our knowledge, the HB2GV Dashboard is the first open-access, curated database of HBM guidance values developed for use in interpreting HBM data. This new resource can assist global HBM data users such as risk assessors, risk managers and biomonitoring programs with a readily available compilation of guidance values.

The effects of prenatal bisphenol A exposure on brain volume of children and young mice

Bisphenol A (BPA) is a synthetic chemical used for the manufacturing of plastics, epoxy resin, and many personal care products. This ubiquitous endocrine disruptor is detectable in the urine of over 80% of North Americans. Although adverse neurodevelopmental outcomes have been observed in children with high gestational exposure to BPA, the effects of prenatal BPA on brain structure remain unclear. Here, using magnetic resonance imaging (MRI), we studied the associations of maternal BPA exposure with children's brain structure, as well as the impact of comparable BPA levels in a mouse model. Our human data showed that most maternal BPA exposure effects on brain volumes were small, with the largest effects observed in the opercular region of the inferior frontal gyrus (ρ = -0.2754), superior occipital gyrus (ρ = -0.2556), and postcentral gyrus (ρ = 0.2384). In mice, gestational exposure to an equivalent level of BPA (2.25 μg BPA/kg bw/day) induced structural alterations in brain regions including the superior olivary complex (SOC) and bed nucleus of stria terminalis (BNST) with larger effect sizes (1.07≤ Cohens d ≤ 1.53). Human (n = 87) and rodent (n = 8 each group) sample sizes, while small, are considered adequate to perform the primary endpoint analysis. Combined, these human and mouse data suggest that gestational exposure to low levels of BPA may have some impacts on the developing brain at the resolution of MRI.

Quantification of Urinary Sex Steroids in the Big Brown Bat (Eptesicus fuscus)

AbstractBats (order Chiroptera) are the second largest group of mammals, diverging ~52.5 million years ago. Many species exhibit an unusual reproductive cycle and extreme longevity without reproductive senescence, yet steroid profiles exist for few bats. Big brown bats (Eptesicus fuscus) are temperate insectivores found throughout North America. They mate promiscuously in fall, store sperm during winter hibernation, and have delayed ovulation and fertilization in spring. Here, we report the first urinary steroid profile in bats by quantifying 17β-estradiol (E₂) in captive male and female E. fuscus across their reproductive cycle. Male bats had higher urinary E₂ levels than females, and adults had higher levels than yearlings following creatinine adjustment for hydration. In nonpregnant females, several seasonal differences in creatinine-adjusted and unadjusted urinary E₂ levels were observed. Urinary E₂ was higher in males than females in winter for both conditions and in autumn for creatinine-adjusted levels. We quantified progesterone (P₄) in a subset of females. In nonpregnant females, urinary P₄ was constant across seasons except for unadjusted levels, which were highest in the summer. In pregnant females, urinary E₂ and P₄ levels peaked beginning ~20 d before parturition, with both steroids returning to baseline in the following weeks. Knowing how urinary steroid levels fluctuate with age and sex and across the annual season is key to understanding reproductive cycling in bats. Our research furthers the potential for bats as a model for medical reproductive research. Moreover, it complements previous studies on the potential role of steroids in primer pheromonal effects in bats.

Trends in environmental chemical concentrations in the Canadian population: Biomonitoring data from the Canadian Health Measures Survey 2007-2017

Ten years of nationally representative biomonitoring data collected between 2007 and 2017 are available from the Canadian Health Measures Survey (CHMS). These data establish baseline environmental chemical concentrations in the general population. Here we sought to evaluate temporal trends in environmental chemical exposures in the Canadian population by quantifying changes in biomarker concentrations measured in the first five two-year cycles of the CHMS. We identified 39 chemicals that were measured in blood or urine in at least three cycles and had detection rates over 50% in the Canadian population. We calculated geometric mean concentrations for each cycle using the survey weights provided. We then conducted analyses of variance to test for linear trends over all cycles. We also calculated the percent difference in geometric means between the first and most recent cycle measured. Of the 39 chemicals examined, we found statistically significant trends across cycles for 21 chemicals. Trends were decreasing for 19 chemicals from diverse chemical groups, including metals and trace elements, phenols and parabens, organophosphate pesticides, per- and polyfluoroalkyl substances, and plasticizers. Significant reductions in chemical concentrations included di-2-ethylhexyl phthalate (DEHP; 75% decrease), perfluorooctane sulfate (PFOS; 61% decrease), perfluorooctanoic acid (PFOA; 58% decrease), dimethylphosphate (DMP; 40% decrease), lead (33% decrease), and bisphenol A (BPA; 32% decrease). Trends were increasing for two pyrethroid pesticide metabolites, including a 110% increase between 2007 and 2017 for 3-phenoxybenzoic acid (3-PBA). No significant trends were observed for the remaining 18 chemicals that included arsenic, mercury, fluoride, acrylamide, volatile organic compounds, and polycyclic aromatic hydrocarbons. National biomonitoring data indicate that concentrations, and therefore exposures, have decreased for many priority chemicals in the Canadian population. Concentrations for other chemical groups have not changed or have increased, although average concentrations remain below thresholds of concern derived from human exposure guidance values. Continued collection of national biomonitoring data is necessary to monitor trends in exposures over time.

Exposure Load: Using biomonitoring data to quantify multi-chemical exposure burden in a population

People are often concurrently exposed to numerous chemicals. Here we sought to leverage existing large biomonitoring datasets to improve our understanding of multi-chemical exposures in a population. Using nationally-representative data from the 2012-2015 Canadian Health Measures Survey (CHMS), we developed Exposure Load, a metric that counts the number of chemicals measured in people above a defined concentration threshold. We calculated Exposure Loads based on five concentration thresholds: the analytical limit of detection (LOD) and the 50th, 75th, 90th and 95th percentiles. Our analysis considered 44 analyte biomarkers representing 26 chemicals from the 2012-2015 CHMS; complete biomarker data were available for 1858 participants aged 12-79 years following multiple imputation of results that were missing due to sample loss. Chemicals may have one or more biomarkers, and for the purposes of Exposure Load calculation, participants were considered to be exposed to a chemical if at least one biomarker was above the threshold. Distributions of Exposure Loads are reported for the total population, as well as by age group, sex and smoking status. Canadians had an Exposure Load between 9 and 21 (out of 26) when considering LOD as the threshold, with the majority between 13 and 18. At higher thresholds, such as the 95th percentile, the majority of Canadians had an Exposure Load between 0 and 3, although some people had an Exposure Load of up to 15, indicating high exposures to multiple chemicals. Adolescents aged 12-19 years had significantly lower Exposure Loads than adults aged 40-79 years at all thresholds and adults aged 20-39 years at the 50th and 75th percentiles. Smokers had significantly higher Exposure Loads than nonsmokers at all thresholds except the LOD, which was expected given that tobacco smoke is a known source of certain chemicals included in our analysis. No differences in Exposure Loads were observed between males and females at any threshold. These findings broadly suggest that Canadians are concurrently exposed to many chemicals at lower concentrations and to fewer chemicals at high concentrations. They should assist in identifying vulnerable subpopulations disproportionately exposed to numerous chemicals at high concentrations. Future work will use Exposure Loads to identify prevalent chemical combinations and their link with adverse health outcomes in the Canadian population. The Exposure Load concept can be applied to other large datasets, through collaborative efforts in human biomonitoring networks, in order to further improve our understanding of multiple chemical exposures in different populations.

Associations among urinary triclosan and bisphenol A concentrations and serum sex steroid hormone measures in the Canadian and U.S. Populations

Exposure to triclosan, an antimicrobial agent, and bisphenol A (BPA), the monomer of polycarbonate plastics, is widespread. Endocrine-disrupting impacts of these chemicals have been demonstrated in in vitro studies, rodent toxicology studies, and some human observational studies. Here we compared urinary concentrations of triclosan and BPA in the Canadian and U.S. populations using nationally-representative data from the 2012-2015 Canadian Health Measures Survey (CHMS) and the 2013-2016 National Health and Nutrition Examination Survey (NHANES). We then examined the cross-sectional associations of urinary triclosan or BPA with serum sex steroid hormones, including estradiol (E2), progesterone (P4), and testosterone (T), using multivariable regression. We observed differences in creatinine-standardized chemical concentrations between countries; urinary triclosan was higher in Canadian females aged 12-19 years, while BPA was higher in U.S. females aged 20-49 years. We also found significant associations among urinary chemicals and serum E2 and T, but not P4. Increasing triclosan was associated with higher levels of E2 in 6-11-year-old girls, but with lower levels of E2 and T in adolescent boys aged 12-19 years. Increasing BPA was associated with lower levels of E2 in 6-11-year-old boys and in adolescents aged 12-19 years of either sex. We observed a U-shaped association between urinary triclosan and E2 in male adults aged 50-79 years; no associations between BPA and hormones were detected in adults. These results, in accordance with the in vitro and animal literature, suggest that triclosan and BPA exposures may be cross-sectionally associated with altered reproductive hormone levels, especially in children and adolescents. Further research and prospective studies are necessary to elucidate country-specific differences in chemical exposures and the potential public health significance of these findings.

Concentrations of urinary parabens and reproductive hormones in girls 6-17 years living in Canada

BACKGROUND

Parabens are chemical substances used as preservatives for their antibacterial and antifungal properties in many personal care products, and sometimes in pharmaceutical and food products. Concerns for adverse human health effects arise from animal studies showing endocrine disrupting effects, such as changes in the timing of puberty and alterations in reproductive hormone activity. Our objective was to examine the association between urinary concentrations of parabens and serum concentrations of estradiol, progesterone, follicle stimulating hormone [FSH], and luteinizing hormone [LH]) in girls from the general population.

METHODS

We conducted a cross-sectional study in girls ages 6-17 years, using data from the Canadian Health Measures Survey (2014-2015). The association between concentrations of creatinine-standardized urinary parabens and serum hormone concentrations was analyzed with multivariable linear regressions, adjusting for potential confounders (i.e., age, body mass index, ethnicity, household income, sampling season; prenatal exposure to cigarette smoke for girls 6-11 years).

RESULTS

The 382 girls and teens included in the study had a mean age of 11.0 years; 76% were white and 73% had a body mass index in the range normal/underweight. Most participants (92%) had least one paraben detected in their urine. Girls with higher urinary paraben concentrations had significantly lower serum concentrations of estradiol, LH, and FSH, but not of progesterone. A doubling in the sum of urinary parabens was associated with 5.8% lower estradiol (95% CI -9.3, -2.1), 4.2% lower FSH (95% CI -7.9, -0.3), and 10.8% lower LH (95% CI -17.4, -3.7). The analysis of individual compounds showed that all four parabens were similarly associated with lower concentrations of estradiol, FSH, and LH. We further analyzed younger girls (6-11 years) and found that urinary parabens were similarly associated with lower estradiol and LH (doubling in the sum of parabens associated with 5.9% lower estradiol [95% CI -10.5, -1.0] and 10.9% lower LH [95% CI -20.2, -0.6]). In this younger subgroup, the association estimate for FSH, however, was attenuated and no longer statistically significant.

DISCUSSION

We observed that exposure to parabens was associated with reduced concentrations of circulating reproductive hormones, suggesting that these chemicals could alter the development and function of the endocrine system in girls. Further prospective research using long-term assessment of parabens exposure and of reproductive development may better determine endocrine disrupting effects of parabens.

Seasonal transfer and quantification of urinary estradiol in the big brown bat (Eptesicus fuscus)

Growing evidence shows that sex steroids not only act within the individual whose glands produce them; they can also act on proximate conspecifics. Previous studies show that exogenous 17β-estradiol (E₂) can be absorbed both nasally and percutaneously, arriving in blood, neural, reproductive, and peripheral tissues. When male bats were injected with radiolabeled E₂ (³H-E₂) and housed with females during the mating season, radioactivity was reliably measured in the females' tissues. The present study was designed to compare E₂ transfer from male to female bats at three time points in the annual reproductive cycle: spring (ovulation and fertilization), summer (maternal season), and autumn (mating season). Pairs of mature female bats were housed with a mature ³H-E₂-treated male (50 μCi). Following 48 h of communal housing, radioactivity was measured in the tissues of female bats. Higher levels of radioactivity were present in the uterus and other tissues during the spring and autumn seasons compared to the summer season. We also measured natural levels of bioactive, unconjugated E₂ in the urine of male bats using enzyme immunoassays, and found that it was present in all three seasons but at lower levels during the summer. Male-excreted E₂ could transfer to females within the close confines of a roost, potentially influencing their reproductive physiology and behavior. These results suggest increased E₂ transfer coincides with female reproduction, with urine as a likely vector. We suggest that sex steroid transfer among interacting individuals may explain several mammalian phenomena historically viewed as "pheromonal".

Prenatal maternal and childhood bisphenol a exposure and brain structure and behavior of young children

BACKGROUND

Bisphenol A (BPA) is commonly used in the manufacture of plastics and epoxy resins. In North America, over 90% of the population has detectable levels of urinary BPA. Human epidemiological studies have reported adverse behavioral outcomes with BPA exposure in children, however, corresponding effects on children's brain structure have not yet been investigated. The current study examined the association between prenatal maternal and childhood BPA exposure and white matter microstructure in children aged 2 to 5 years, and investigated whether brain structure mediated the association between BPA exposure and child behavior.

METHODS

Participants were 98 mother-child pairs who were recruited between January 2009 and December 2012. Total BPA concentrations in spot urine samples obtained from mothers in the second trimester of pregnancy and from children at 3-4 years of age were analyzed. Children participated in a diffusion magnetic resonance imaging (MRI) scan at age 2-5 years (3.7 ± 0.8 years). Associations between prenatal maternal and childhood BPA and children's fractional anisotropy and mean diffusivity of 10 isolated white matter tracts were investigated, controlling for urinary creatinine, child sex, and age at the time of MRI. Post-hoc analyses examined if alterations in white matter mediated the relationship of BPA and children's scores on the Child Behavior Checklist (CBCL).

RESULTS

Prenatal maternal urinary BPA was significantly associated with child mean diffusivity in the splenium and right inferior longitudinal fasciculus. Splenium diffusivity mediated the relationship between maternal prenatal BPA levels and children's internalizing behavior (indirect effect: β = 0.213, CI [0.0167, 0.564]). No significant associations were found between childhood BPA and white matter microstructure.

CONCLUSIONS

This study provides preliminary evidence for the neural correlates of BPA exposure in humans. Our findings suggest that prenatal maternal exposure to BPA may lead to alterations in white matter microstructure in preschool aged children, and that such alterations mediate the relationship between early life exposure to BPA and internalizing problems.

Factors affecting interpretation of national biomonitoring data from multiple countries: BPA as a case study

INTRODUCTION

The use of biomonitoring data as an indicator of national levels of human exposure to environmental chemicals has grown in importance and prevalence. Nationally representative urinary bisphenol A (BPA) data are now available for Canada, the United States and Korea. Here we address the following questions: Are urinary BPA data from these countries comparable? What can be discerned regarding geographic and/or temporal similarities or differences? Are there generalizable lessons to be learned regarding comparison of biomonitoring results from different countries?

METHODS

We examined underlying methods and resultant urinary BPA data from national surveys of three countries: Canada (Canadian Health Measures Survey, CHMS, 2009-2015); United States (National Health and Nutrition Examination Survey, NHANES, 2009-2014); and Korea (Korean National Environmental Health Survey, KoNEHS, 2009-2014). We estimated BPA daily intakes on both a volume- and creatinine-adjusted basis.

RESULTS

The three countries use similar methods for analyzing urine samples for BPA and participate in external proficiency testing with acceptable results. Field blanks are only used in the CHMS program. There were program-specific differences in fasting times of participants. Median urinary BPA levels in Canada remained relatively constant over the three cycles (1.1-1.2 ng/ml), while US levels decreased (from 1.9 to 1.3 ng/ml) and Korean levels increased (from 0.7 to 1.1 ng/ml) over similar time periods. The most recent survey year data indicate that levels do not differ substantially across countries. Canadian urinary BPA levels have been stable; the subtle, non-significant decrease in intakes may be due to higher body weight in the more recent Canadian surveys. In contrast, the decrease in intakes in the US appears to be due to decreases in urinary BPA as body weights in the US have been stable. Estimated 95th percentile intakes are over an order of magnitude below current health-based guidance values.

DISCUSSION

Our assessment of urinary BPA data from Canada, the US and Korea indicates that methodological differences, methods for dilution adjustment, and population characteristics should be carefully considered when interpreting biomonitoring data. Despite the plethora of publications describing issues with use of creatinine levels for urinary dilution adjustment, there have been no major methodological advances that would assist in interpreting urinary chemical data. A combination of biomonitoring and traditional exposure assessment approaches may be needed to fully assess human exposures to BPA and other chemicals.

CONCLUSIONS

National biomonitoring surveys provide important information on population levels of chemicals such as BPA and can assist in understanding temporal and geographic similarities, differences, and trends. However, caution must be exercised when using these data to draw anything but broad conclusions, due to both intercountry methodological differences and factors affecting urinary chemical levels that are still poorly understood. While the issues raised in this paper do not appear to be a major concern specifically for the national-scale monitoring of BPA described here, they must be considered when comparing data for other chemicals measured as part of both national and smaller-scale biomonitoring-based research as well as for BPA data from other studies.

A mixture of five endocrine-disrupting chemicals modulates concentrations of bisphenol A and estradiol in mice

Most people in developed countries are exposed to multiple endocrine-disrupting synthetic chemicals. We previously showed that a single dose of triclosan, tetrabromobisphenol A (TBBPA), butyl paraben, propyl paraben, or di(2-ethylhexyl) phthalate elevated concentrations of bisphenol A (BPA) in mice. Here we investigated whether concurrent exposure to lower doses of these five chemicals could modulate concentrations of bisphenol A (BPA) or the natural estrogen, 17β-estradiol (E2). CF1 mice were injected subcutaneously with 0.1 or 0.5 mg of one chemical, or a 0.5 mg mixture containing 0.1 mg of each of all five chemicals, then given dietary 50 μg kg^-114C-BPA. The mixture elevated ¹⁴C-BPA concentrations in the lungs, muscle, uterus, ovaries, kidney, and blood serum of female mice. When administered alone, triclosan and TBBPA elevated ¹⁴C-BPA concentrations in the uterus, ovaries, and blood serum. In another experiment, CF1 mice were injected subcutaneously with the 0.5 mg mixture containing 0.1 mg of all five chemicals, then E2 was measured in urine 2-12 h later. The mixture elevated E2 at 8 h after injection in female mice. No treatments significantly altered concentrations of ¹⁴C-BPA or E2 in male mice. These data show that these endocrine-disrupting chemicals interact in vivo, magnifying one another's effects, consistent with inhibition of enzymes that are critical for estrogen metabolism. These findings highlight the importance of considering exposure to multiple chemicals when assessing health outcomes and determining regulatory exposure limits.

Influence of Tetrabromobisphenol A, with or without Concurrent Triclosan, upon Bisphenol A and Estradiol Concentrations in Mice

BACKGROUND

Humans are commonly exposed to multiple environmental chemicals, including tetrabromobisphenol A (TBBPA; a flame retardant), triclosan (an antimicrobial agent), and bisphenol A (BPA; polycarbonate plastics). These chemicals are readily absorbed and may interact with each other.

OBJECTIVES

We sought to determine whether TBBPA, given alone or in combination with triclosan, can modulate the concentrations of BPA and 17β-estradiol (E2).

METHODS

Female and male CF-1 mice were each given a subcutaneous injection of 0-27mg TBBPA, with or without concurrent 0.33mg triclosan, followed by dietary administration of 50μg/kg body weight ¹⁴C-BPA. Radioactivity was measured in blood serum and tissues through liquid scintillation counting. In subsequent experiments, female and male CF-1 mice were each given a subcutaneous injection of 0 or 1mg TBBPA and E2 was measured in urine 2-12 h after injection.

RESULTS

Doses as low as 1mg TBBPA significantly elevated ¹⁴C-BPA concentrations in the uterus and ovaries of females; in the testes, epididymides, vesicular-coagulating glands, and preputial glands of males; and in blood serum, heart, lungs, and kidneys of both sexes; urinary E2 concentrations were also elevated. Lower doses of TBBPA or triclosan that had no effects on their own elevated ¹⁴C-BPA concentrations when the two substances were given concurrently.

CONCLUSION

These data indicate that TBBPA, triclosan, and BPA interact in vivo, consistent with evidence that TBBPA and triclosan inhibit enzymes that are critical for BPA and E2 metabolism. https://doi.org/10.1289/EHP1329.

Progesterone transfer among cohabitating female big brown bats (Eptesicus fuscus)

Experiments using female mice and bats have demonstrated that tritium-labeled 17β-estradiol (³H-E₂) can be absorbed via cutaneous and intranasal routes and distributed to reproductive and neural tissues. Radioactivity has also been measured in tissues of untreated females after 48h cohabitation with ³H-E₂ injected males. The present study was designed to quantify steroid transfer among female bats. Radioactive quantification via liquid scintillation counting revealed absorption of tritium-labeled progesterone (³H-P₄) in adult females 1h after cutaneous and intranasal application (10μCi). Subsequently, pairs of mature females were each housed for 48h with a single mature female that had been administered ³H-P₄ (50μCi) via intraperitoneal injection. Radioactivity was observed in all collected tissues of all non-injected females at levels significantly greater than the control group. Following the same paradigm, radioactivity was not observed in the tissues of untreated female bats that were housed with stimulus females treated with ³H-E₂ (50μCi). Enzyme immunoassays revealed measurable levels of unconjugated progesterone and estradiol in the urine of female bats, suggesting urine as a vector for steroid transfer. Given that bats of this species live in predominantly female roosts in very close contact, progesterone transfer among individuals is likely to occur in natural roosts.

Diethylhexyl phthalate magnifies deposition of 14 C-bisphenol A in reproductive tissues of mice

Endocrine disrupting chemicals are found in diverse common products, including cosmetics, food packaging, thermal receipt paper and plastic containers. This exposes most people in developed countries through ingestion, skin absorption and inhalation. Two ubiquitous endocrine disrupting chemicals, bisphenol A (BPA) and diethylhexyl phthalate (DEHP) can interact in disrupting blastocyst implantation in inseminated females. We hypothesized that DEHP might increase the bioavailability of BPA in tissues by competing for metabolic enzymes. We injected 0, 3, 9 or 18 mg DEHP into female and male mice and allowed 30 min for the chemical to circulate before giving them a food supplement containing 50 μg kg^{-1 14} C-BPA. Animals were dissected 1 h following ¹⁴ C-BPA administration and various tissue samples were acquired. Samples were solubilized and radioactivity was measured via liquid scintillation counting. In cycling females, DEHP increased BPA deposition in the muscle, uterus, ovaries and blood serum relative to controls. In peri-implantation females, DEHP increased deposition of BPA in the uterus, ovaries and serum relative to controls. In males, DEHP doses increased BPA deposition in serum and epididymis relative to controls. These results are consistent with the hypothesis that DEHP competes with BPA for conjugating enzymes such as UDP-glucuronosyltransferase, thereby magnifying the presence of BPA in estrogen-binding reproductive tissues. Copyright © 2017 John Wiley & Sons, Ltd.

Absorption and distribution of estradiol from male seminal emissions during mating

Estradiol-17β (E₂) plays critical roles in female maturation, sexual receptivity, ovulation and fertility. In many mammals, contact with males can similarly affect these female parameters, whereas male excretions contain significant quantities of E₂ We administered radiolabeled estradiol ([³H]E₂) to male mice in doses representing a small fraction of their endogenous E₂ These males were paired with sexually receptive females, and radioactivity was traced into the females' systems. In Experiment 1, males were given [³H]E₂ at 24 and 1 h before mating. Male-to-female [³H]E₂ transfer intensified with increasing numbers of intromissions and spiked in the uterus after insemination. In Experiment 2, sexually experienced young males received [³H]E₂ at 72 and 24 h before mating, and all mated to ejaculation. The copulatory plug deposited in the female reproductive tract contained substantial levels of radioactivity. The uteri, other tissues and blood serum of females displayed radioactivity indicative of E₂ transfer. In Experiment 3, radioactivity was observed 3 and 18 h after insemination in the females' uteri and other tissues, including parts of the brain. In Experiment 4, we observed substantial levels of radioactivity in semen as well as the copulatory plugs retrieved from the females after mating. Transferred E₂ could directly affect abundant estrogen receptors in the female reproductive tract without potential metabolism by the liver. Sexually transferred E₂ may facilitate uterine preparation for blastocyst implantation. These data converge with several lines of evidence indicating that male-sourced E₂ can transfer to proximate females in bioactive form, contributing to various mammalian pheromonal effects.

Triclosan elevates estradiol levels in serum and tissues of cycling and peri-implantation female mice

Triclosan, an antimicrobial agent added to personal care products, can modulate estrogenic actions. We investigated whether triclosan affects concentrations of exogenous and endogenous estradiol. Female mice were given injections of triclosan followed by 1μCi tritium-labeled estradiol. Mice given daily 2-mg triclosan doses (57.9mg/kg/dose) showed significantly elevated radioactivity in tissues and serum compared to controls. A single dose of 1 or 2mg triclosan increased radioactivity in the uterus in both cycling and peri-implantation females. We also measured natural urinary estradiol at 2-12h following triclosan injection. Unconjugated estradiol was significantly elevated for several hours following 1 or 2mg of triclosan. These data are consistent with evidence that triclosan inhibits sulfonation of estrogens by interacting with sulfotransferases, preventing metabolism of these steroids into biologically inactive forms. Elevation of estrogen concentrations by triclosan is potentially relevant to anti-reproductive and carcinogenic actions of excessive estrogen activity.

Estradiol transfer from male big brown bats (Eptesicus fuscus) to the reproductive and brain tissues of cohabiting females, and its action as a pheromone

The powerful estrogen, 17β-estradiol, has been found to pass from male excretions to the reproductive organs, brain, and other tissues of cohabiting females in laboratory mice. The current studies were designed to examine whether this phenomenon also occurs in big brown bats (Eptesicus fuscus), a mammal appropriate for testing cross-species generality because of its phylogenetic distance from mice. When tritiated estradiol ((3)H-E2) was administered directly on the nasal area of adult female bats, radioactivity was reliably observed in the uterus and ovaries, and also in the brain and other tissues. When (3)H-E2 was applied to the skin, radioactivity was observed in reproductive and other peripheral tissues. We injected male bats with minute quantities of (3)H-E2 and housed each of them directly with groups of adult females for 48h. We then measured radioactivity in male and female bat tissues. In each of several replications of one male housed with three females, radioactivity was reliably observed in the uterus of all females, and in many other tissues in almost every female. Measurement in the organs of males directly exposed to (3)H-E2 showed high levels of radioactivity in the testes and especially the epididymides. These data indicate that estradiol is transferred from males to females, likely via absorptions from males' excretions and potentially also via intravaginal exposure during mating. Given the potency of estradiol in regulating female reproductive physiology and behavior, our data strongly suggest the potential for pheromonal action whereby male mammals induce sexual receptivity and ovulation in females.

Transfer of [³H]estradiol-17β and [³H]progesterone from conspecifics to cohabiting female mice

Estradiol-17β (E₂) and progesterone (P₄) play critical roles in female reproductive physiology and behavior. Given the sensitivity of females to exogenous sources of these steroids, we examined the presence of E₂ and P₄ in conspecifics' excretions and the transfer of excreted steroids between conspecifics. We paired individual adult female mice with a stimulus male or female conspecific given daily injections of [³H]E₂ or [³H]P₄. Following 48  h of direct interaction with the stimulus animal, we measured radioactivity in the uterus, ovaries, muscle, olfactory bulbs, mesencephalon and diencephalon (MC+DC), and cerebral cortex of the untreated female cohabitant. Radioactivity was significantly present in all tissues of female subjects after individual exposure to a stimulus male or female given [³H]E₂. In females exposed to males given [³H]P₄, radioactivity was significantly present in the uterus, ovaries, and muscle, but not in other tissues. In females exposed to stimulus females given [³H]P₄, radioactivity was significantly present in all tissues except the MC+DC. In mice directly administered [³H]steroids, greater radioactivity was found in the urine of females than of males. Among females directly administered [³H]steroids, greater radioactivity was found in urine of those given [³H]P4 than of those given [³H]E₂. When females were administered unlabeled E₂ before exposure to [³H]E₂-treated females, less radioactivity was detected in most tissues than was detected in the tissues of untreated females exposed to [³H]E₂-treated females. We suggest that steroid transfer among individuals has implications for the understanding of various forms of pheromonal activity.

Nonsteroidal anti-inflammatory drugs (NSAIDs) versus opioids for acute renal colic

BACKGROUND

Renal colic is a common cause of acute severe pain. Both opioids and nonsteroidal anti-inflammatory drugs (NSAIDs) are recommended for treatment, but the relative efficacy of these drugs is uncertain.

OBJECTIVES

To examine the benefits and disadvantages of NSAIDs and opioids for the management of pain in acute renal colic.

SEARCH STRATEGY

We searched the Cochrane Renal Group's specialised register (May 2003), the Cochrane Central Register of Randomised Controlled Trials (CENTRAL - The Cochrane Library issue 2, 2003), MEDLINE (1966 - 31 January 2003), EMBASE (1980 - 31 January 2003) and handsearched reference lists of retrieved articles. Most recent search date: January 2005

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing any opioid with any NSAID, regardless of dose or route of administration were included.

DATA COLLECTION AND ANALYSIS

Data was extracted and quality assessed independently by two reviewers, with differences resolved by discussion. Dichotomous outcomes are reported as relative risk (RR) and measurements on continuous scales are reported as weighted mean differences (WMD) with 95% confidence intervals. Subgroup analysis by study quality, drug type and drug route have been performed where possible to explore reasons for heterogeneity.

MAIN RESULTS

Twenty trials from nine countries with a total of 1613 participants were identified. Both NSAIDs and opioids lead to clinically significant falls in patient-reported pain scores. Due to unexplained heterogeneity these results could not be pooled although 10/13 studies reported lower pain scores in patients receiving NSAIDs. Patients treated with NSAIDs were significantly less likely to require rescue medication (RR 0.75, 95% CI 0.61 to 0.93, P = 0.007), though most of these trials used pethidine. The majority of trials showed a higher incidence of adverse events in patients treated with opioids, but there was significant heterogeneity between studies so the results could not be pooled. There was significantly less vomiting in patients treated with NSAIDs (RR 0.35, 95% CI 0.23 to 0.53, P < 0.00001). In particular, patients receiving pethidine had a much higher rate of vomiting compared with patients receiving NSAIDs. Gastrointestinal bleeding and renal impairment were not reported.

AUTHORS' CONCLUSIONS

Both NSAIDs and opioids can provide effective analgesia in acute renal colic. Opioids are associated with a higher incidence of adverse events, particularly vomiting. Given the high rate of vomiting associated with the use of opioids, particularly pethidine, and the greater likelihood of requiring further analgesia, we recommend that if an opioid is to be used it should not be pethidine.

Nonsteroidal anti-inflammatory drugs (NSAIDs) versus opioids for acute renal colic

BACKGROUND

Renal colic is a common cause of acute severe pain. Both opioids and nonsteroidal anti-inflammatory drugs (NSAIDs) are recommended for treatment, but the relative efficacy of these drugs is uncertain.

OBJECTIVES

To examine the benefits and disadvantages of NSAIDs and opioids for the management of pain in acute renal colic.

SEARCH STRATEGY

We searched the Cochrane Renal Group's specialised register (May 2003), the Cochrane Central Register of Randomised Controlled Trials (CENTRAL - The Cochrane Library issue 2, 2003), MEDLINE (1966 - 31 January 2003), EMBASE (1980 - 31 January 2003) and handsearched reference lists of retrieved articles.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing any opioid with any NSAID, regardless of dose or route of administration were included.

DATA COLLECTION AND ANALYSIS

Data was extracted and quality assessed independently by two reviewers, with differences resolved by discussion. Dichotomous outcomes are reported as relative risk (RR) and measurements on continuous scales are reported as weighted mean differences (WMD) with 95% confidence intervals. Subgroup analysis by study quality, drug type and drug route have been performed where possible to explore reasons for heterogeneity.

MAIN RESULTS

Twenty trials from nine countries with a total of 1613 participants were identified. Both NSAIDs and opioids lead to clinically significant falls in patient-reported pain scores. Due to unexplained heterogeneity these results could not be pooled although 10/13 studies reported lower pain scores in patients receiving NSAIDs. Patients treated with NSAIDs were significantly less likely to require rescue medication (RR 0.75, 95% CI 0.61 to 0.93, P = 0.007), though most of these trials used pethidine. The majority of trials showed a higher incidence of adverse events in patients treated with opioids, but there was significant heterogeneity between studies so the results could not be pooled. There was significantly less vomiting in patients treated with NSAIDs (RR 0.35, 95% CI 0.23 to 0.53, P < 0.00001). In particular, patients receiving pethidine had a much higher rate of vomiting compared with patients receiving NSAIDs. Gastrointestinal bleeding and renal impairment were not reported.

REVIEWER'S CONCLUSIONS

Both NSAIDs and opioids can provide effective analgesia in acute renal colic. Opioids are associated with a higher incidence of adverse events, particularly vomiting. Given the high rate of vomiting associated with the use of opioids, particularly pethidine, and the greater likelihood of requiring further analgesia, we recommend that if an opioid is to be used it should not be pethidine.

Progressive tension sutures: a technique to reduce local complications in abdominoplasty

Abdominoplasty has evolved as a very effective and satisfactory procedure, especially when combined with liposuction and the repair of diastasis recti. However, local complications, including hematoma and seroma formation, flap necrosis, and hypertrophic scars, continue to plague this procedure. The authors present a relatively simple and reproducible technique that allows extensive liposuction in conjunction with abdominoplasty; they think this technique reduces the incidence of local complications. This technique, the use of progressive tension sutures, has been used in their practice for more than 15 years. A retrospective review of 65 consecutive abdominoplasty patients demonstrates a very low local complication rate when compared with historical controls. In this series of both full and modified abdominoplasty patients who were followed for an average of 18 months, the authors had no hematomas, seromas, or skin flap necrosis.

Phase II study of merbarone (NSC 336628) in patients with advanced gastric carcinoma

Merbarone, 5-(N-phenylcarboxamido)-2-thiobarbituric acid (NSC 336628), is a derivative of barbituric acid and represents a unique class of antineoplastic agents. We treated 16 patients with advanced gastric carcinoma in a phase II study of merbarone. All patients were previously untreated with chemotherapy or biological therapy. The starting dose of merbarone was 1000mg/m2 infused over 24 hr for 5 consecutive days every 21 days. A median of two courses (range, 1-7) was given. None of the patients achieved a complete or partial response; however, 3 patients achieved a transient minor response. Toxicity was mild to moderate in most patients, but 1 patient died of treatment-related neutropenia and sepsis. Our data suggest that merbarone at this dose and schedule is inactive against gastric carcinoma. The evidence of minor response suggests that analog research may be worthwhile to pursue.

Phase II trial of trimetrexate in untreated advanced gastric carcinoma. A Southwest Oncology Group study

Twenty-three evaluable patients with advanced gastric adenocarcinoma were treated with trimetrexate at doses of 8-12 mg/m2 intravenously daily for five days, with cycles repeated every 21 days. One complete response was seen for an overall response rate of 4% (95% confidence interval 0-22%). Hematologic toxicities of grade > or = 3 were seen in 10/23 patients, and overall any grade 3 or greater toxicity was seen in 14/23 patients. Trimetrexate has minimal activity against gastric adenocarcinoma in this study, and no further investigation of this agent at this dose and schedule is recommended in this disease.

A phase II study of menogaril (NSC-269148) in colorectal carcinoma. A Southwest Oncology Group study

In this phase II trial, menogaril was administered to patients with metastatic colon cancer at a dose of 200 mg/m2 IV over one hour with cycles repeated every 28 days provided the absolute granulocyte count was greater than or equal to 2000 cells/microliters. Dose adjustments up or down were made depending upon nadir counts. Twenty-four patients were entered on this study with 21 eligible and evaluable for response. There was 1 CR lasting four and one-half months and 1 PR lasting three months for an overall CR + PR rate of 10% with a 95% confidence interval of 1% to 30%. Six patients (29%) had stable disease and 13 (62%) progressed. Median survival is 13.1 months. Toxicity was primarily hematologic with two cases of life-threatening leukopenia (less than 1000 cells/microliters) and one case of life-threatening granulocytopenia (less than 250 cells/microliters) among the 21 eligible patients, and one case of life-threatening leukopenia and granulocytopenia in one ineligible patient. There were no deaths due to treatment.