Publications by authors named "Greylin Nielsen"
Adverse lung outcomes from exposure to per-and polyfluoroalkyl substances (PFAS) are known; however, the mechanism of action is poorly understood. To explore this, human bronchial epithelial cells were grown and exposed to varied concentrations of short-chain (perfluorobutanoic acid, perflurobutane sulfonic acid and GenX) or long-chain (PFOA and perfluorooctane sulfonic acid (PFOS)) PFAS, alone or in a mixture to identify cytotoxic concentrations. Non-cytotoxic concentrations of PFAS from this experiment were selected to assess NLRP3 inflammasome activation and priming.
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- The global production of industrial chemicals is rising, leading to health risks and disproportionate impacts on low-wealth and communities of color.
- Multiple health organizations are urging improved regulations to protect against harmful exposures.
- A set of five consensus recommendations aims to enhance EPA policies, emphasizing accountability for chemical producers, recognizing potential hazards even without data, better protecting at-risk populations, reevaluating assumptions about "safe" exposure levels, and addressing conflicts of interest in risk assessments.
Human health risk assessment currently uses the reference dose or reference concentration (RfD, RfC) approach to describe the level of exposure to chemical hazards without appreciable risk for non-cancer health effects in people. However, this "bright line" approach assumes that there is minimal risk below the RfD/RfC with some undefined level of increased risk at exposures above the RfD/RfC and has limited utility for decision-making. Rather than this dichotomous approach, non-cancer risk assessment can benefit from incorporating probabilistic methods to estimate the amount of risk across a wide range of exposures and define a risk-specific dose.
View Article and Find Full Text PDFHuman exposure to per- and polyfluoroalkyl substances (PFAS) is ubiquitous, with mixtures of PFAS detected in drinking water, food, household dust, and other exposure sources. Animal toxicity studies and human epidemiology indicate that PFAS may act through shared mechanisms including activation of peroxisome proliferator activated receptor α (PPARα). However, the effect of PFAS mixtures on human relevant molecular initiating events remains an important data gap in the PFAS literature.
View Article and Find Full Text PDFTo determine if a 12-week yoga intervention (YI) was associated with increased gamma aminobutyric acid (GABA) levels and decreased depressive symptoms in participants with major depressive disorder (MDD). : Subjects were randomized to a high-dose group (HDG) of three YIs a week and a low-dose group (LDG) of two YIs a week. Thalamic GABA levels were obtained using magnetic resonance spectroscopy at Scan-1 before randomization.
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- Evidence suggests yoga may effectively treat major depressive disorder (MDD), with the study aiming to determine the impact of different yoga "doses" on MDD symptoms.
- A total of 32 participants were assigned to either a high-dose or low-dose group for 12 weeks, and both groups showed significant improvements in various psychological measures.
- Although the high-dose group had better outcomes, the differences weren't statistically significant, indicating the need for further research, especially as both interventions were effective in reducing depression and anxiety symptoms.