Search

Nunavimmiut (Inuit of Nunavik, Northern Quebec, Canada) exhibit a high selenium (Se) status because of their frequent consumption of marine mammal foods. Indirect evidence from our previous studies had suggested that selenoneine – a novel selenocompound – may be accumulating in the blood of Nunavimmiut. We used a liquid-chromatography/inductively coupled tandem mass spectrometry (LC-ICP-MS/MS) method to measure concentrations of selenoneine and its methylated metabolite Se-methylselenoneine in archived red blood cells (RBC) obtained from 210 Nunavimmiut living in communities along the Hudson Strait, where marine mammal hunting and consumption are most frequent in Nunavik. This method was adapted to quantify selenoneine and its methylated metabolite in beluga mattaaq, an Inuit delicacy consisting of the skin with the underlying layer of fat and the major dietary source of Se for Nunavimmiut. Total selenium concentration was also measured in RBC and beluga mattaaq samples by isotope dilution ICP-MS/MS. The median selenoneine concentration in RBC was 413 μg Se/L (range = 3.20–3230 μg Se/L), representing 54% (median) of total Se content (range = 1.6–91%). Quantification of selenoneine in five beluga mattaaq samples (skin layer) from Nunavik revealed a median concentration of 1.8 μg Se/g wet wt (range = 1.2–7.4 μg Se/g), constituting 54% (median) of the total Se content (range = 44–74%). Se-methylselenoneine was also detected in Inuit RBC but not in beluga mattaaq, suggesting that selenoneine undergoes methylation in humans. Selenoneine may protect Nunavimmiut from methylmecury toxicity by increasing its demethylation in RBC and in turn decreasing its distribution to target organs. Image 1 • LC-ICP-MS/MS was used to quantify selenoneine and Se-methylselenoneine in RBCs. • Selenoneine represented 54% of total Se content in Inuit RBCs. • Selenoneine was also the major Se species in beluga mattaaq – an Inuit delicacy. • Selenoneine may protect Inuit against methylmercury toxicity. [ABSTRACT FROM AUTHOR]

Perfluoroalkyl substances (PFASs) are known to be toxic, bioaccumulative, and persistent. However, exposure routes and toxic effects to humans are still widely unknown. Our objectives were to evaluate potential correlations between concentrations of PFASs in maternal plasma and infant cord blood with home characteristics and developmental effects, including wheezing. The concentrations of 17 PFASs were measured in plasma from prenatal women (n = 414), postnatal women (n = 247), and cord blood (n = 50) from a subset of participants in a population-based birth cohort in Winnipeg, Manitoba, Canada, using online solid phase extraction (SPE) with liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Multiple linear regression and principal component analysis (PCA) were used to evaluate possible associations with PFAS concentrations. Surveys were used to collect information regarding maternal characteristics (e.g. age, parity, duration of breastfeeding), infant characteristics (e.g. birth weight, birth length, head circumference, gestational age, and incidence of recurrent wheezing), and home characteristics (e.g. home age,carpet coverage in the most used room, presence of new furniture, or recent home renovations). PFASs in plasma were associated with maternal characteristics but not home characteristics or early childhood wheezing. PFASs were not associated with developmental effects, with the exception that perfluoroundecanoic acid (PFUA) was negatively associated with birth weight. Further studies investigating the potential influences of PFUA on birth weight are warranted. Image 1 • PFASs in pre- and postnatal blood were associated with maternal characteristics. • PFASs in pre- and postnatal blood were not associated with home characteristics. • Perfluoroundecanoic acid (PFUA) was negatively associated with birth weight. • No correlations between PFASs in blood and incidence of recurrent wheeze in infants. • Perfluoropentanoic acid (PFPA) was among the higher measuring analytes in blood. Principal component analysis showed that PFASs in maternal blood were related to maternal characteristics and, for the most part, not home characteristics or developmental effects. [ABSTRACT FROM AUTHOR]

The increasing variability of the illicit drug market has imposed serious health risks for people who use drugs (PWUD), particularly due to the increasing co-occurrence of opioids and etizolam (or other benzodiazepines) in some jurisdictions. A miniature mass spectrometer (MS) equipped with paper capillary spray ionization was evaluated for its ability to quantify fentanyl, fluorofentanyl, carfentanil, and etizolam in illicit drug samples. Prior to testing actual drug samples, inter- and intra-day reproducibility, calibration linearity, and analytical sensitivity were assessed. The development of a continuous spray solvent delivery system improved MS/MS quantitation by prolonging ionization stability. A simple, rapid and quantitative tandem mass spectrometry method was developed and employed for the analysis of real-world illicit drug samples provided by PWUD at a harm reduction site in Victoria, British Columbia, Canada. Limits of detection ranged from 0.001 to 0.24% w/w of illicit analyte in the original solid drug samples. Target analytes were detected and quantified via the miniature MS system for samples where conventional on-site drug checking technologies were not always effective. These promising results demonstrate the potential role for miniature mass spectrometer systems for on-site drug checking services that can be both sensitive to trace, toxic levels as well as adaptable/selective for new drug threats as they appear in the illicit drug supply. [Display omitted] • The increased variability of the illicit drug market has imposed serious health risks for people who use drugs (PWUD). • A rapid & quantitative miniature MS method was developed and employed for the analysis of real-world illicit drug samples. • Target analytes were quantified via miniature MS, where other on-site drug checking technologies were not always effective. • Miniature MS systems for on-site drug checking services are sensitive, adaptable and selective for new drug threats. [ABSTRACT FROM AUTHOR]

Abstract: Phthalate metabolites are often measured in biomonitoring studies to evaluate a population's exposure to ubiquitous phthalates. During the course of national biomonitoring studies in Canada, we identified an issue with the accuracy of several commercial phthalate metabolite standards that are commonly used in such studies. The validity of the results from these studies was then questioned. Altogether, three (3) large studies were affected, involving a total of 9302 samples and 105000 individual phthalate metabolite measurements. Data from our previous investigation suggested that the inaccuracies in the commercially-available phthalate metabolite standards were compound- and lot-specific. Therefore, an approach was developed to derive correction factors for each lot of phthalate metabolite standard and was applied to the previously-acquired measurements with the goal of obtaining accurate and comparable data. A statistical analysis was performed to support the approach. It is expected that the corrected phthalate metabolite data from all three Canadian biomonitoring studies are comparable to one another. However, caution is still advised when comparing data obtained from biomonitoring studies for which the calibration standards have not been investigated for their accuracy. Suggestions are made based on quality assurance aspects to improve the validity of phthalate metabolite measurements. [Copyright &y& Elsevier]

Abstract: In recent times, there has been an increased concern over the appearance of human estrogens in marine ecosystem and their effects on the marine habitat. Discharge of raw sewage has been identified as one of the most important sources of human estrogens in the marine environment. Therefore, we have developed a gas chromatography–(ion-trap) mass spectrometry/mass spectrometry method for the analysis of natural estrogens estrone (E1), and 17β-estradiol (E2) and synthetic estrogens 17α-ethynylestradiol (EE2) and diethylstilbestrol (DES) in sewage effluents, seawater and mussels. Recovery of target analytes from mussels (n =3) was above 60% with RSD ranging from 8% to 13%. For aqueous samples (n =3) recoveries were above 80% with RSD ranging from 3% to 7%. Method detection limits for the target analytes ranged from 0.1ngg−1 to 1.0ng/g for mussel sample analysis and from 0.5ngL−1 to 1.2ngL−1 for water sample analysis. The usefulness of the method was demonstrated by analyzing environmental samples from St. John’s and Halifax, Canada, where raw sewage is directly discharged into the harbors. Estrone and 17 β-estradiol were found at 1.5ngL−1 and 1.8ngL−1 in seawater samples collected from St. John’s harbor, while trace amounts of estrone was measured in some mussels collected from Halifax harbor. [Copyright &y& Elsevier]

Soxhlet (SE), microwave-assisted (MAE) and ultrasound-assisted (UAE) extraction were compared using ten extraction solvents for their efficiency to extract phenolic and flavonoid antioxidants from Eastern Canada propolis. Extracts were compared for total phenolic (TPC) and total flavonoid (TFC) content, and radical scavenging activities. Anti-inflammatory activity through inhibition of 5-lipoxygenase (5-LO) products biosynthesis in HEK293 cells was also evaluated. The results showed that SE extracts using polar solvents had the highest TPC and TFC. Extracts obtained with ethanol, methanol and acetone were effective free radical scavengers, and showed 5-LO inhibition similar to zileuton. UAE was an effective extraction method since the extracts obtained were comparable to those using SE and the MAE while being done at room temperature. With UAE, extracts of less polar solvents showed similar free radical scavenging and 5-LO inhibition to extracts of much more polar solvents such as methanol or ethanol. Reversed-phase liquid chromatography tandem mass spectrometry confirmed the presence of 21 natural compounds in the propolis extracts based on the comparison of intact mass, chromatographic retention time and fragmentation patterns derived from commercial analytical standards. The current study is the first of its kind to concurrently investigate solvent polarity as well as extraction techniques of propolis. [ABSTRACT FROM AUTHOR]