What the lab can and cannot do: clinical interpretation of drug testing results.

Urine drug testing is one of the objective tools available to assess adherence. To monitor adherence, quantitative urinary results can assist in differentiating "new" drug use from "previous" (historical) drug use. "Spikes" in urinary concentration can assist in identifying patterns of drug use. Coupled chromatographic-mass spectrometric methods are capable of identifying very small amounts of analyte and can make clinical interpretation rather challenging, specifically for drugs that have a longer half-life. Polypharmacy is common in treatment and rehabilitation programs because of co-morbidities. Medications prescribed for comorbidities can cause drug-drug interaction and phenoconversion of genotypic extensive metabolizers into phenotypic poor metabolizers of the treatment drug. This can have significant impact on both pharmacokinetic (PK) and pharmacodynamic properties of the treatment drug. Therapeutic drug monitoring (TDM) coupled with PKs can assist in interpreting the effects of phenoconversion. TDM-PKs reflects the cumulative effects of pathophysiological changes in the patient as well as drug-drug interactions and should be considered for treatment medications/drugs used to manage pain and treat substance abuse. Since only a few enzyme immunoassays for TDM are available, this is a unique opportunity for clinical laboratory scientists to develop TDM-PK protocols that can have a significant impact on patient care and personalized medicine. Interpretation of drug screening results should be done with caution while considering pharmacological properties and the presence or absence of the parent drug and its metabolites. The objective of this manuscript is to review and address the variables that influence interpretation of different drugs analyzed from a rehabilitation and treatment programs perspective.

Association of In Utero Exposure to Polybrominated Diphenyl Ethers With the Risk of Hypospadias.

Importance: Polybrominated diphenyl ethers (PBDEs) are added to many consumer products as flame retardants, and their endocrine-disrupting properties are a growing health concern in pregnancy. Objective: To investigate whether in utero PBDE exposure as measured in maternal hair is associated with increased risk for hypospadias. Design, Setting, and Participants: In this case-control study, the setting was the urology clinic of a tertiary pediatric hospital between January 3, 2011, and April 1, 2013. Participants were children diagnosed as having hypospadias and their mothers and a control group of children without hypospadias and their mothers. Dates of data analysis were September 3, 2017, to December 28, 2017. Exposures: Gestational exposure to 8 PBDEs as measured in the 3-cm segment closest to the skull of maternal hair by gas chromatography-mass spectroscopy as a proxy for in utero exposure. The mothers resided in the same household for the duration of their pregnancy. Main Outcomes and Measures: Difference in total maternal hair PBDE levels between the hypospadias and control groups. Results: Total PBDE levels were significantly higher among mothers of infants with hypospadias (n = 152) (total PBDE level, 51.4 pg/mg; interquartile range, 35.8-78.5 pg/mg) than among controls (n = 64) (total PBDE level, 35.8 pg/mg; interquartile range, 18.1-69.9 pg/mg) (P = .02). Of the 152 women with sufficient hair samples for analysis in the case group, 89 completed a questionnaire and were included in a multivariable analysis, and of the 64 women with sufficient hair samples for analysis in the control group, 54 completed a questionnaire and were included in a multivariable analysis. Adjusting for potential confounders, hypospadias was associated with a relative 48.2% (95% CI, 23.2%-65.4%) higher maternal level of total PBDE levels in the multivariable analysis. Conclusions and Relevance: In this analysis, mothers of children with hypospadias were exposed during pregnancy to significantly higher levels of PBDEs. The results of this study suggest that level of exposure to PBDEs during gestation may have a role in the etiology of hypospadias.

Exposure to polybrominated diphenyl ethers and phthalates in healthy men living in the greater Montreal area: A study of hormonal balance and semen quality.

Studies investigating the associations between exposure of young men to polybrominated diphenyl ethers (PBDEs) or phthalates and hormone levels or semen quality have produced inconsistent results. Our goal was to investigate the association of exposure to PBDEs or phthalate metabolites with changes in markers of thyroid (TSH, free T3 and free T4) and reproductive function (sperm concentrations, motility, and quality; serum LH and testosterone) in 153 healthy young men from the greater Montreal area. Using covariate-adjusted models, we found that each 10-fold increase in BDE-47 was associated with lower TSH levels (-17.3%; 95% CI: -31.5, 0.0; p = 0.05). BDE-47 exposure was also associated with a decrease in sperm concentration (-19.7%; 95% CI: -36.8; 2.0; p = 0.07) and motility (-25.5%; 95% CI: -44.5, 0.1; p = 0.05). Trends towards decreases in these parameters were also observed in association with exposure to BDE-100 and the sum of BDE-47, -99, and -100 (∑3BDEs). These associations were not accompanied by effects on sperm chromatin quality, as assessed with the HT-COMET assay. There were no substantial associations between urinary phthalate metabolite concentrations, either individually or grouped by molecular weight or parent compound, and sperm quality parameters; however, there was a positive association between elevated MECCP and free T4 (0.98; 95% CI: 0.02, 1.94; p = 0.05). Inverse associations between BDE-47 and ∑3BDEs and free T3 and positive associations between MEHP and free T3 were stronger among individuals with BMI ≥ 25, suggesting that weight status may modify the effects of these endocrine disrupting chemicals.

Erratum: "A Case-Control Study of Maternal Polybrominated Diphenyl Ether (PBDE) Exposure and Cryptorchidism in Canadian Populations".

[This corrects the article DOI: 10.1289/EHP522.].

A Case-Control Study of Maternal Polybrominated Diphenyl Ether (PBDE) Exposure and Cryptorchidism in Canadian Populations.

BACKGROUND: Polybrominated diphenyl ethers (PBDEs) are flame retardants found in North American household products during the past four decades. These chemicals leach out in dust as products age, exposing individuals daily through inhalation and ingestion. Animal studies suggest that PBDEs disrupt sex hormones and adversely affect development of the reproductive system. OBJECTIVES: In the present study, we examined whether there is a link between maternal hair PBDE concentrations and the risk of cryptorchidism (undescended testes) in male infants; testis descent is known to be dependent on androgens. METHODS: Full-term male infants were recruited through clinics in Montreal, Toronto, and London, Canada. Boys with cryptorchidism at 3-18 months of age (n=137) were identified by pediatric urologists and surgeons; similar-aged controls (n=158) had no genitourinary abnormalities as assessed by pediatricians. Eight BDE congeners (BDE-28, -47, -99, -100, -153, -154, -183, -209) were measured by GC-MS (gas chromatography-mass spectrometry) in maternal hair samples collected at the time of recruitment. RESULTS: The ∑PBDE geometric mean for maternal hair was 45.35 pg/mg for controls and 50.27 pg/mg for cases; the concentrations of three BDEs (BDE-99, -100, and -154) were significantly higher in cases than controls in unadjusted models. In adjusted models, every 10-fold increase in the concentration of maternal hair BDE-99 [OR=2.53 (95% CI: 1.29, 4.95) or BDE-100 [OR=2.45 (95% CI: 1.31, 4.56)] was associated with more than a doubling in the risk of cryptorchidism. BDE-154 [OR=1.88 (95% CI: 1.08, 3.28) was also significant. CONCLUSIONS: Our results suggest that maternal exposure to BDE-99, -100, and -154 may be associated with abnormal migration of testes in the male fetus. This may be due to the anti-androgenic properties of the PBDEs. https://doi.org/10.1289/EHP522.

Oral morphine dosing predictions based on single dose in healthy children undergoing surgery.

BACKGROUND: Oral morphine has been proposed as an effective and safe alternative to codeine for after-discharge pain in children following surgery but there are few data guiding an optimum safe oral dose. AIMS: The aim of this study was to characterize the absorption pharmacokinetics of enteral morphine in order to simulate time-concentration profiles in children given common oral morphine dose regimens. METHODS: Children (2-6 years, n = 34) undergoing elective surgery and requiring opioid analgesia were randomized to receive preoperative oral morphine (100 mcg·kg-1 , 200 mcg·kg-1 , 300 mcg·kg-1 ). Blood sampling for morphine assay was performed at 30, 60, 90, 120, 180, and 240 min. Morphine serum concentrations were determined by liquid chromatography-mass spectroscopy and pharmacokinetic parameters were calculated using nonlinear mixed effects models. Current data were pooled with published time-concentration profiles from children (n = 1059, age 23 weeks postmenstrual age - 3 years) administered intravenous morphine, to determine oral bioavailability (F), absorption lag time (TLAG ), and absorption half-time (TABS ). These parameter estimates were used to predict concentrations in children given oral morphine (100, 200, 300, 400, 500 mcg·kg-1 ) at different dosing intervals (3, 4, 5, 6, 8, 12 h). RESULTS: The oral morphine formulation had F 0.298 (CV 36.5%), TLAG 0.45 (CV 63.6%) h and TABS 0.71 (CV 55%) h. A single-dose morphine 100 mcg·kg-1 achieved a mean CMAX 10 mcg·l-1 . Repeat 4-hourly dosing achieved mean steady-state concentration 13-18 mcg·l-1 ; concentrations associated with good analgesia after intravenous administration. Serum concentration variability was large ranging from 5 to 55 mcg·l-1 at steady state. CONCLUSIONS: Oral morphine 200 mcg·kg-1 then 100 mcg·kg-1 4 h or 150 mcg·kg-1 6 h achieves mean concentrations associated with analgesia. There was high serum concentration variability suggesting that respiration may be compromised in some children given these doses.

Evaluating external contamination of polybrominated diphenyl ethers in human hair: clinical and research implications.

BACKGROUND: Human hair is a well-validated matrix for detecting a variety of xenobiotics, including drugs of abuse (cocaine, tetrahydrocannabinol, and morphine) and fatty acid ethyl ethers. Recent studies have shown that hair can also be useful in determining an individual's exposure to polybrominated diphenyl ethers (PBDEs), flame retardants that contaminate the dust in our daily environment. Hair processing before assay varies with each analyte; in particular, the wash protocol must be optimized to remove external contaminants while not affecting levels of the chemical of interest. The aim of this study was to determine whether hair needs to be washed before analysis for PBDEs, and if so, which protocol is most effective to ensure that the level of PBDEs is neither overestimated nor underestimated. METHOD: Individual hair samples from 10 adults (5 men and 5 women) were subjected to 4 different wash protocols: (1) no wash, (2) water, (3) 10% sodium dodecyl sulfate (SDS), and (4) hexane. Both the washes and hair were analyzed for 8 PBDEs by gas chromatography/mass spectrometry. RESULTS: The sum of PBDEs (ΣPBDEs) in the washes was (1) no wash: 0 pg/mg, (2) water: 0.39 ± 0.19 (mean ± SEM), (3) 10% SDS: 1.34 ± 0.68, and (4) hexane: 1.92 ± 0.87. The ΣPBDEs in the hair were: (1) no wash: 20.32 ± 3.05, (2) water: 20.30 ± 2.41, (3) 10% SDS: 19.27 ± 1.87, and (4) hexane: 16.91 ± 2.89. Washing with water, 10% SDS, and hexane decreased the PBDE levels by 1.9%, 7%, and 11.4%, respectively (P < 0.05). CONCLUSIONS: Thus, of the washes evaluated, water is the wash that had the least effect on total PBDE concentrations, providing the best evaluation of an individual's exposure to PBDEs.

Glyburide transport across the human placenta.

OBJECTIVE: To estimate the magnitude of transplacental transfer of glyburide in women with gestational diabetes mellitus (GDM). METHODS: A prospective, observational study was conducted on women with GDM on glyburide therapy. On delivery admission, the glyburide dose and time of last dose were recorded. Immediately postdelivery, maternal and umbilical venous blood samples were obtained and the concentrations of glyburide were determined by high-performance liquid chromatography-mass spectrometry with a limit of detection of 0.25 ng/mL. RESULTS: Nineteen patient dyads were analyzed. The mean total daily maternal glyburide dose was 6.6±6.3 mg per day and the mean time between last dose and sampling was 13.3±6.5 hours. The mean maternal serum glyburide level at birth was 15.4±20.8 ng/mL, whereas the mean umbilical glyburide level was 7.5±8.2 ng/mL, which showed a statistical correlation (r=0.72, P<.01). There were statistically significant relationships between total maternal glyburide dose (1.25-20 mg per day) and maternal glyburide levels (0.93-70.71 ng/mL; r=0.46, P≤.01) and between total maternal glyburide dose and umbilical glyburide levels (0.95-32.41 ng/mL; r=0.43, P≤.01) However, we observed wide variability in maternal and umbilical glyburide levels at both extremes of the total glyburide dose. Seventy-nine percent of cord samples (15/19) had glyburide levels less than 10 ng/mL (the limit of detection reported in earlier studies) and 37% (7/19) were higher than the corresponding maternal samples. CONCLUSION: Transplacental transfer of glyburide is highly variable among patients, corroborating ex vivo placental perfusion studies showing a transport-mediated glyburide efflux from the fetal to the maternal circulation. In most neonates (79%), glyburide levels were below 10 ng/mL. LEVEL OF EVIDENCE: III.

A Compartmental Analysis for Morphine and Its Metabolites in Young Children After a Single Oral Dose.

BACKGROUND AND OBJECTIVES: Currently, the majority of the surgical procedures performed in paediatric hospitals are done on a day care basis, with post-operative pain being managed by caregivers at home. Pain after discharge of these post-operative children has historically been managed with oral codeine in combination with paracetamol (acetaminophen). Codeine is an opioid, which elicits its analgesic effects via metabolism to morphine and codeine-6-glucuronide. Oral morphine is a feasible alternative for outpatient analgesia; however, the pharmacokinetics of morphine after oral administration have been previously described only sparsely, and there is little information in healthy children. METHODS: The clinical trial included 40 children from 2 to 6 years of age, with an American Society of Anaesthesiologists physical status classification of 1 or 2, who were undergoing surgical procedures requiring opioid analgesia. Morphine was orally administered prior to surgery in one of three doses: 0.1 mg/kg, 0.2 mg/kg and 0.3 mg/kg. Blood samples were collected for plasma morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) concentrations at 30, 60, 90, 120, 180 and 240 min after administration. All analyses were performed with the non-linear mixed-effect modelling software NONMEM version 7.2, using the first-order conditional estimation (FOCE) method. RESULTS: A pharmacokinetic model was developed to simultaneously describe the plasma profiles of morphine and its metabolites M3G and M6G after a single dose of oral morphine in young children (2-6 years of age). The disposition of morphine, M3G and M6G in plasma was best described by a one-compartment model. M3G and M6G metabolite formation was best described by a delay transit compartment, indicating a delay in the appearance of these two major metabolites. CONCLUSION: This model provides a foundation on which to further evaluate the use of oral morphine and its safety in young children. Longer follow-up time for morphine oral doses and incorporation of other important covariates, such as phenotype, will add value and will help overcome the limitations of the presented population pharmacokinetic analysis.

Hair as a biomarker of systemic exposure to polybrominated diphenyl ethers.

The efficacy of using hair as a biomarker for exposure to polybrominated diphenyl ether (PBDE) flame retardants was assessed in humans and an animal model. Paired human hair and serum samples were obtained from adult men and women (n = 50). In parallel, hair, serum, liver, and fat were collected from adult male Sprague-Dawley rats exposed to increasing doses of the PBDE mixture found in house dust for 70 days via the diet. All samples were analyzed by GC-MS for eight common PBDEs: BDE-28, -47, -99, -100, -153, -154, -183, and -209. Paired human hair and serum samples had five congeners (BDE-28, -47, -99, -100, and -154) with significant individual correlations (0.345-0.566). In rat samples, BDE-28 and BDE-183 were frequently below the level of detection. Significant correlations were observed for BDE-47, -99, -100, -153, -154, and -209 in rat hair, serum, liver, and fat across doses, with r values ranging from 0.803 to 0.988; weaker correlations were observed between hair and other tissues when data from the lowest dose group or for BDE-209 were analyzed. Thus, human and rat hair PBDE measurements correlate strongly with those in alternative matrices, validating the use of hair as a noninvasive biomarker of long-term PBDE exposure.

Ethanol impairs intestinal barrier function in humans through mitogen activated protein kinase signaling: a combined in vivo and in vitro approach.

BACKGROUND: Ethanol-induced gut barrier disruption is associated with several gastrointestinal and liver disorders. AIM: Since human data on effects of moderate ethanol consumption on intestinal barrier integrity and involved mechanisms are limited, the objectives of this study were to investigate effects of a single moderate ethanol dose on small and large intestinal permeability and to explore the role of mitogen activated protein kinase (MAPK) pathway as a primary signaling mechanism. METHODS: Intestinal permeability was assessed in 12 healthy volunteers after intraduodenal administration of either placebo or 20 g ethanol in a randomised cross-over trial. Localization of the tight junction (TJ) and gene expression, phosphorylation of the MAPK isoforms p38, ERK and JNK as indicative of activation were analyzed in duodenal biopsies. The role of MAPK was further examined in vitro using Caco-2 monolayers. RESULTS: Ethanol increased small and large intestinal permeability, paralleled by redistribution of ZO-1 and occludin, down-regulation of ZO-1 and up-regulation of myosin light chain kinase (MLCK) mRNA expression, and increased MAPK isoforms phosphorylation. In Caco-2 monolayers, ethanol increased permeability, induced redistribution of the junctional proteins and F-actin, and MAPK and MLCK activation, as indicated by phosphorylation of MAPK isoforms and myosin light chain (MLC), respectively, which could be reversed by pretreatment with either MAPK inhibitors or the anti-oxidant L-cysteine. CONCLUSIONS: Administration of moderate ethanol dosage can increase both small and colon permeability. Furthermore, the data indicate a pivotal role for MAPK and its crosstalk with MLCK in ethanol-induced intestinal barrier disruption. TRIAL REGISTRATION: ClinicalTrials.gov NCT00928733.

Transfer of dabigatran and dabigatran etexilate mesylate across the dually perfused human placenta.

OBJECTIVE: To assess the transplacental pharmacokinetics at term of the oral thrombin inhibitor, dabigatran, and its prodrug, dabigatran etexilate mesylate, to estimate fetal drug exposure. METHODS: Placentae were obtained with informed consent after cesarean delivery of healthy term pregnancies in Toronto, Ontario, Canada. The transplacental transfer of dabigatran and dabigatran etexilate mesylate was separately assessed using the ex vivo dual perfusion of an isolated human placental cotyledon. Dabigatran, at a concentration of 35 ng/mL, was added to the maternal circulation at the start of the experimental phase. Maternal and fetal samples were taken throughout the preexperimental (1 hour) and experimental (3 hours) phases for measurement of dabigatran and markers of placental viability. Separate placenta perfusions with dabigatran etexilate mesylate were conducted at an initial maternal concentration of 3.5 ng/mL. Dabigatran and dabigatran etexilate mesylate were measured using liquid chromatography-tandem mass spectrometry. RESULTS: There was slower transfer of dabigatran compared with antipyrine from the maternal-to-fetal circulation, because the median fetal-to-maternal concentration ratio was 0.33 (interquartile range 0.29-0.38) after 3 hours (n=3). The prodrug, dabigatran etexilate mesylate, had limited placental transfer as characterized by a fetal-to-maternal ratio of 0.17 (interquartile range 0.15-0.17) after 3 hours (n=3). Placental viability markers for all perfusions were within normal ranges. CONCLUSION: This report provides direct evidence of the transfer of dabigatran and its prodrug across the term human placenta from the mother to the fetus. From a clinical perspective, these data suggest that, pending further study, dabigatran should not be used for anticoagulation of pregnant women, because the drug may have an adverse effect on fetal blood coagulation.

Investigating the use of hair to assess polybrominated diphenyl ether exposure retrospectively.

BACKGROUND: Polybrominated diphenyl ethers (PBDEs) are chemicals that are added to a variety of consumer products as flame-retardants and have been classified as emerging endocrine disruptors. They are persistent and have been detected in humans. Previous studies have suggested that hair is a suitable matrix for examining human exposure to organic pollutants such as PBDEs. It is believed that the majority of exposure is from our indoor environment. The aim of this study was to investigate the changes in PBDE patterns and levels along the hair shaft, by using segmental analysis to retrospectively assess long-term exposure over a 1-year period. METHODS: Questionnaires and hair samples from 65 women were collected at the Hospital for Sick Children, in Toronto, as part of a larger study. To assess long-term stability, hair samples were separated into 4- and 3-cm segments representing a 1-year period. Hair segments were analyzed for levels of 8 PBDE congeners, BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183, and BDE-209 on gas chromatography-mass spectrometry (MS). A Friedman test was used to detect the differences in exposure among segments, and factors such as dietary habits, hair care routine, and site of residence were investigated to determine if they might affect hair levels. RESULTS: A significant increase (P < 0.0001) in total PBDEs was seen among segments moving from proximal (root end) to distal along the hair shaft (median in pg/mg): first (33.3), second (43.0), third (61.6), and fourth (75.5) segments. Significantly lower levels of PBDEs were observed in artificially colored hair samples (P = 0.032), and a significant increase in PBDE levels was observed in women who consumed meat on a daily basis as opposed to weekly consumption (P = 0.040). CONCLUSIONS: The increase in PBDEs along the hair shaft suggests that hair PBDEs may be influenced by diet and artificial coloring. More work is needed to validate the use of PBDEs in hair as a biomarker of long-term exposure.

The detection and quantification of ethyl glucuronide in placental tissue and placental perfusate by headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry.

BACKGROUND: Ethyl glucuronide (EtG) is arising as a promising biomarker of heavy prenatal alcohol exposure, however its transfer across the human placenta is still unclear and is currently being investigated using the ex vivo placental perfusion model. This model allows for sampling from placental tissue and placental perfusate, which is a surrogate to plasma. OBJECTIVE: To develop a method for detecting and quantifying EtG in placental perfusate and tissue using headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). METHODS: A method was optimized by manipulation of the following components to attain the highest peak counts for the quantifying ions of EtG and its deuterated internal standard on the mass spectrum: cartridges used for solid phase extraction, injection method, derivatizing agent, pre-injection parameters, SPME fiber, GC ramp speed, and GC column flow. RESULTS: The final method utilized involved solid phase extraction of standards via UCT CleanScreen Cartridges, derivatization with heptafluorobutyric acid, and introduction into the GC via HS-SPME with adsorption to a polydimethylsiloxane fiber. The method has improved sensitivity over other methods that quantify EtG in blood using GC-MS, with detection limits of 1.6 ng/mL and 13.7 ng/g for placental perfusate and tissue, respectively. The method was applied to samples collected from the fetal reservoir during the ex vivo placental perfusion model and EtG was detected in the fetal circulation after 20 minutes of perfusion, indicating transfer of EtG. CONCLUSIONS: The present method is sensitive and can be used to quantify EtG transfer during ex vivo placental perfusion experiments.

Hair as a biomarker of polybrominated diethyl ethers' exposure in infants, children and adults.

Over the last 20 years hair has moved from being a highly questionable biological matrix to mainstream and acceptable biomarker in forensic sciences where it is primarily used to determine past and present exposure to illicit drugs. In contrast, the use of hair to assess exposure to pesticides and persistent environmental pollutants is still not common. The applicability of this matrix to assess an individual's body burden of chemicals such as polybrominated diethyl ethers (PBDEs) can provide critical insight into current, but also to past exposure levels, which is not possible with more conventional matrices such as blood and urine. Furthermore, as PBDEs cross the placenta and since the hair the fetus is born with begins to grow during the third trimester, this matrix can be used to assess in utero exposure. These features of hair may therefore be used to determine the potential roles of chemicals such as PBDEs in mediating physiological or anatomical abnormalities in infants, children or adults.

N-acetylcysteine as a novel prophylactic treatment for ifosfamide-induced nephrotoxicity in children: translational pharmacokinetics.

Ifosfamide (IFO), which is used in the treatment of pediatric solid tumors, causes high rates of nephrotoxicity. N-acetylcysteine (NAC), an antidote for acetaminophen overdose, has been shown to prevent IFO-induced renal cell death and nephrotoxicity in both LLCPK-1 cells and a rat model. To facilitate the use of NAC in preventing IFO-induced nephrotoxicity in children, the authors compared the systemic exposure to NAC in children treated for acetaminophen overdose to the systemic exposure of the therapeutically effective rat model. The mean systemic exposure in the rat model was 18.72 mM·h (range, 9.92-30.02 mM·h), compared to the mean systemic exposure found in treated children (14.48 mM·h; range, 6.22-32.96 mM·h). They also report 2 pediatric cases in which NAC-attenuated acute renal failure associated with IFO when given concurrently with their chemotherapy treatment. Systemic exposure to NAC measured in 1 of these cases was comparable to that in the children treated for acetaminophen overdose. These results corroborate NAC's potential to protect against IFO-induced nephrotoxicity in children when used in its clinically approved dose schedule and supports a clinical trial in children.

Simultaneous detection of seventeen drugs of abuse and metabolites in hair using solid phase micro extraction (SPME) with GC/MS.

INTRODUCTION: The analysis of pediatric and adult hair is a useful non-invasive biomarker to effectively detect long term exposure to various xenobiotics, specifically drugs of abuse such as cocaine, opiates and amphetamines. Very often individuals are using, or are exposed to multiple drugs simultaneously and therefore it is important to be able to detect them in the same analysis. We have developed a sensitive and specific solid phase micro extraction (SPME) coupled with gas chromatography mass spectrometry (GC/MS) to detect 17 different analytes in hair using a single extraction method. METHOD: Five milligrams of hair is extracted overnight, subjected to solid phase extraction (SPE) and then to SPME-GC/MS. The aimed analytes include amphetamine, methamphetamine, MDA, MDMA, cocaine, benzoylecognine, norcocaine, cocaethylene, methadone, codeine, morphine, 6-AM, oxycodone, oxymorphone, hydrocodone, hydromorphone and meperidone. RESULTS: The following are the LOD of the various drugs: 0.2ng/mg hair for amphetamine, methamphetamine, MDA, MDMA, morphine, codeine, 6-AM, oxycodone, oxymorphone, hydromorphone, hydrocodone, meperidine and 0.13ng/mg hair for cocaine, benzoylecognine, cocaethylene, norcocaine and methadone. CONCLUSION: This GC/MS method is sensitive and specific to detect the presence of these 17 analytes in as little as 5mg of hair and is especially useful for newborn and child hair analysis where the amount of hair is often very limited.

Detection of polybrominated biphenyl ethers (PBDEs) in pediatric hair as a tool for determining in utero exposure.

INTRODUCTION: Cryptorchidism, or undescended/maldescended testis, is the most common birth defect of male genitalia. Its prevalence has been increasing over the past few decades. This may be due to an increase in the prevalence of anti-androgenic chemicals such as polychlorinated biphenyls, organochloride pesticides, plasticizers and fungicides. A newer group of chemicals, brominated flame retardants (BFRs), are being implicated as endocrine-disrupting chemicals. These chemicals are used worldwide in polymers that are incorporated into a variety of consumer products (e.g., textile, computers and televisions, insulating foam, electrical equipment and kitchen appliances). In order to quantify BFRs we introduce the use of hair levels of polybrominated diphenyl esters (PBDEs) as biomarkers of systemic exposure. This approach will allow for the estimation of in utero BFR exposure, in the process of evaluating the potential link between the incidence of cryptorchidism in newborn males and level of exposure of the pregnant mother to environmentally relevant BFRs. For that end we have developed a GC/MS assay in which children's hair is analyzed for the presence of polybrominated biphenyl ethers (PBDEs). METHODS: In this pilot, 10-40mg of hair from 24 children (12 newborn and 12 from children 1 to 15 years) was extracted overnight at 40°C with 4N HCl and hexane (4:1). The samples were eluted from 2g NaSO(4):2g Florisil SPE columns with 8mL hexane. Dried samples are reconstituted with anhydrous isooctane and injected onto a GC/MS and analyzed for BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183 and BDE-209. RESULTS: PBDEs were detected in all of the newborn and child hair. The ΣPBDE ranged from 0.038 to 1.01pg/mg newborn hair and from 0.208 to 2.695ng/mg child hair. The most abundant PBDE in newborn hair was BDE-153 while in child hair the variable PBDEs were BDE-47 and BDE-99. The highest molecular weight congener BDE-209 was detected in 10/24 pediatric hair samples. The LOQ is 0.0625pg/mg (BDE-209 0.625pg/mg) and the efficiency of extraction was between 70 and 90%. CONCLUSION: This GC/MS method is sufficiently sensitive to detect the presence of all 8 PBDE congeners tested in as little as 10mg of pediatric hair. The results show that PBDEs are present in newborn hair, making this matrix useful in examining in utero exposure to PBDEs and linking it to cryptorchidism.