Updating the Standards of Professional Competence in the Field of Toxicology: The Second Generation of Best Practice.

The American Board of Toxicology (ABT), in consultation with ACT Credentialing & Career Services (ACT), performed a practice analysis study of general toxicology in 2020-21. This work follows up on an initial practice analysis commissioned by the ABT and conducted in 2014-2015, results of which were published in 2016. The purpose of the current, second-generation study was to update and validate the existing process-based delineation of practice of general toxicologists, including major domains of responsibility and tasks performed in practice.

Biological fate of low-calorie sweeteners.

With continued efforts to find solutions to rising rates of obesity and diabetes, there is increased interest in the potential health benefits of the use of low- and no-calorie sweeteners (LNCSs). Concerns about safety often deter the use of LNCSs as a tool in helping control caloric intake, even though the safety of LNCS use has been affirmed by regulatory agencies worldwide. In many cases, an understanding of the biological fate of the different LNSCs can help health professionals to address safety concerns.

Muscarinic receptor-activated signal transduction pathways involved in the neuritogenic effect of astrocytes in hippocampal neurons.

Astrocytes have been shown to release factors that affect various aspects of neuronal development. We have previously shown that the acetylcholine analog carbachol, by activating muscarinic M(3) receptors in rat astrocytes, increases their ability to promote neuritogenesis in hippocampal neurons. This effect was mediated by an increased expression and release by astrocytes of several permissive factors, a most relevant of which was fibronectin.

Ethanol inhibits neuritogenesis induced by astrocyte muscarinic receptors.

In utero alcohol exposure can lead to fetal alcohol spectrum disorders, characterized by cognitive and behavioral deficits. In vivo and in vitro studies have shown that ethanol alters neuronal development. We have recently shown that stimulation of M(3) muscarinic receptors in astrocytes increases the synthesis and release of fibronectin, laminin, and plasminogen activator inhibitor-1, causing neurite outgrowth in hippocampal neurons.

Shotgun proteomics implicates extracellular matrix proteins and protease systems in neuronal development induced by astrocyte cholinergic stimulation.

Astrocytes play an important role in neuronal development through the release of soluble factors that affect neuronal maturation. Shotgun proteomics followed by gene ontology analysis was used in this study to identify proteins present in the conditioned medium of primary rat astrocytes. One hundred and thirty three secreted proteins were identified, the majority of which were never before reported to be produced by astrocytes.

Modulation of neuritogenesis by astrocyte muscarinic receptors.

Astrocytes have been shown to release factors that have promoting or inhibiting effects on neuronal development. However, mechanisms controlling the release of such factors from astrocytes are not well established. Astrocytes express muscarinic receptors whose activation stimulates a robust intracellular signaling, although the role of these receptors in glial cells is not well understood.