Path to a Profession: How a Physician Assistant Becomes a Physician Assistant.

This pilot study, through the application of phenomenological methodology, considered the physician assistant (PA) profession as a "lived experience" in an attempt to understand how these medical practitioners end up on the PA path and what keeps them there. Additionally, the researchers focused on understanding why specific individuals gravitate towards the PA education option. Major themes that developed during the interviews with eight PAs included personal unfamiliarity with the PA profession during the first two decades of life, the decision to pursue PA training while in undergraduate studies, assuming roles often considered MD/DO specific and the subsequent patient confusion with the difference between a PA and an MD/DO, and significant work satisfaction resulting in the lack of desire to change profession. These themes, especially personal unfamiliarity with the PA profession and patient confusion with the difference between a PA and an MD/DO, promotes an environment that perpetuates a lack of understanding about PAs, particularly in younger (e.g., pre-collegiate) individuals. Considering the consequences of this knowledge gap along with the equivocal validity of a pilot study and the potentially subjective nature of phenomenology, the researchers recommend further investigations, both quantitative and qualitative, to either confirm or repudiate these findings.

Embryo-larval BDE-47 exposure causes decreased pathogen resistance in adult male fathead minnows (Pimephales promelas).

Exposures to polybrominated diphenyl ethers (PBDEs) have been shown to alter immune function in adult organisms across a variety of taxa. However, few if any studies have investigated the long-term consequences of early life stage PBDE exposures on immune function in fish. This study sought to determine the effects of early life stage BDE-47 exposure on pathogen resistance in the fathead minnow (Pimephales promelas) following an extended depuration period (≥180 d). Minnows were exposed to BDE-47 via a combination of maternal transfer and diet through 34 days post fertilization (dpf), raised to adulthood (>215 dpf) on a clean diet, then subjected to pathogen resistance trials. Early life stage exposures to BDE-47 did not affect the ability of females to survive from Yersinia ruckeri infection. However, the survival of BDE-47 exposed males was significantly reduced relative to controls, indicating that developmental exposures to BDE-47 altered male immunity. Because BDE-47 is a known thyroid hormone disruptor and thyroid hormone disruptors have the potential to adversely impact immune development and function, metrics indicative of thyroid disruption were evaluated, as were immune parameters known to be altered in response to thyroid disruption. BDE-47 exposed minnows exhibited signs of thyroid disruption (i.e., reduced growth); however, no alterations were observed in immune parameters known to be influenced by thyroid hormones (i.e., thymus size, expression of genes associated with lymphoid development) suggesting that the observed alterations in immunocompetence may occur through alternative mechanisms. Regardless of the mechanisms responsible, the results of this study demonstrate the potential for early life stage PBDE exposures to adversely impact immunity and illustrate that the immunological consequences of PBDE exposures are sex dependent.

Early Life Stage Exposure to BDE-47 Causes Adverse Effects on Reproductive Success and Sexual Differentiation in Fathead Minnows (Pimephales promelas).

2,2',4,4'-Tetrabromodiphenyl ether (BDE-47), a compound manufactured for use as a flame retardant, is a ubiquitous environmental contaminant and suspected endocrine disruptor. Though several studies have explored the reproductive effects of BDE-47 in adult fish, there is a paucity of data regarding the reproductive effects of early life stage exposure. The goal of this study was to assess the reproductive effects of early life stage BDE-47 exposure in fathead minnows (Pimephales promelas). To achieve this, minnows were exposed to either a low (57.68 µg BDE-47/g Artemia) or high (392.59 µg BDE-47/g Artemia) dose of BDE-47 from fertilization to 34 days postfertilization (dpf) via a combination of maternal transfer and dietary exposure. Larvae were then raised on a clean diet until sexual maturity (∼184 dpf) when reproductive function was evaluated using a 21 day breeding study. Fish exposed to BDE-47 had significantly reduced clutch size and fecundity relative to controls. BDE-47 exposed groups also had female-biased sex ratios and exposed males had fewer tubercles. Overall, this study demonstrates that exposure to BDE-47 during early life stages can alter both sexual differentiation and reproductive function.

The endocrine effects of dietary brominated diphenyl ether-47 exposure, measured across multiple levels of biological organization, in breeding fathead minnows.

The goal of the present study was to evaluate the reproductive function of fathead minnows (Pimephales promelas) exposed to brominated diphenyl ether-47 (BDE-47) at doses lower than those used in previous studies. This was accomplished by evaluating the impacts of BDE-47 exposures across multiple levels of biological organization. Breeding pairs were exposed to BDE-47 via diet for 21 d, during which reproductive success was monitored. At the conclusion of the exposure, fish were euthanized to assess the effects of BDE-47 on sex steroid-related and thyroid-related transcripts, plasma androgen levels, gonadosomatic index (GSI), and secondary sexual characteristics. Several alterations in gene expression were noted including a >2.1-fold decrease in hepatic estrogen receptor α (erα) and a 2.9-fold decrease in ovarian aromatase (arom). In addition, BDE-47-exposed males experienced increases in deiodinase 2 (dio2) expression in brain tissue (∼1.5-fold) and decreases in hepatic transthyretin (ttr) expression (∼1.4-fold). Together, these gene expression alterations suggest the potential for BDE-47 to disrupt endocrine signaling. There were no significant differences in plasma hormone levels, GSI, secondary sexual characteristics, or reproductive success. Overall, the present study demonstrates that exposure to BDE-47 is capable of altering both sex steroid-related and thyroid-related transcripts but that these observed alterations do not necessarily manifest themselves at higher levels of biological organization for the endpoints selected. Environ Toxicol Chem 2016;35:2048-2057. © 2016 SETAC.