Longitudinal Patterns of Food Procurement Over the Course of the COVID-19 Pandemic: Findings From a Canadian Online Household Survey.

Introduction: Consumer food procurement during the COVID-19 pandemic has been understudied. This investigation aimed to longitudinally evaluate food procurement patterns, concern of virus exposure in grocery retailers, and food access challenges over the pandemic among a sample of households in Quebec, Canada. Methods: Online surveys were collected at three time points of the pandemic: first wave in spring 2020 (lockdown period), summer 2020 (deconfinement period), and second wave in winter 2021 (curfew period). Respondents were the household's primary grocery shopper (n = 491). Non-parametric tests and multivariable logistic regression were conducted to compare responses over time and to evaluate characteristics of respondents who regularly used no-contact grocery methods (store pick-up or home delivery). Results: Frequency of in-store grocery shopping was lowest during the lockdown (once per week or less), and significantly increased over time to resemble pre-pandemic frequency. Concern of virus exposure in grocery retailers and disinfection/discarding of food packaging was highest during the lockdown, but significantly decreased over time. At all time points, use of public transit, walking or cycling for grocery shopping was associated with regular use of no-contact grocery methods (curfew odds ratio (OR): 3.13 (95% confidence interval 1.60, 6.14). Age (60 years+) was associated with regular use during the lockdown [OR: 2.27 (1.13, 4.59)]. Conclusion: Among our sample, frequency of in-store grocery shopping was lowest and concern of virus exposure in stores was highest during the lockdown period. No-contact grocery use was associated with transportation mode and potentially with personal risk perception (age).

Proposition of a Minimal Effective Dose of Vigabatrin for the Treatment of Infantile Spasms Using Pediatric and Adult Pharmacokinetic Data.

Vigabatrin is an antiepileptic drug indicated as monotherapy in infantile spasms. However, the pharmacokinetic profile of this compound in infants and young children is still poorly understood, as is the minimal effective dose, critical information given the risk of exposure-related retinal toxicity with vigabatrin. A reasonable approach to determining this minimal dose would be to identify the lowest dose providing a low risk of exposure overlap with the 36-mg/kg dose, which is the highest dose associated with an increased risk for treatment failure, based on randomized dose-ranging data. A population pharmacokinetic model was consequently developed from 28 children (aged 0.4-5.7 years) for the active S(+)-enantiomer, using Monolix software. In parallel, a population model was developed from published adult data and scaled to children using theoretical allometry and maturation of the renal function. A one-compartment model with zero-order absorption and first-order elimination described the pediatric data. Mean population estimates (percentage interindividual variability) for the apparent clearance, apparent distribution volume, and absorption duration were 2.36 L/h (24.5%), 17 L (38%), and 0.682 hours, respectively. Apparent clearance and apparent distribution volume were related to body weight by empirical allometric equations. Monte Carlo simulations evidenced that a daily dose of 80 mg/kg should minimize exposure overlap with the 36-mg/kg dose. Similar results were obtained for the adult model scaled to children. Consequently, a minimal effective dose of 80 mg/kg/day could be considered for patients with infantile spasms.

Determination of the R(-) and S(+)-enantiomers of vigabatrin in human plasma by ultra-high-performance liquid chromatography and tandem mass-spectrometry.

An analytical method was developed for the quantification in plasma of the R and S enantiomers of vigabatrin (VGB), a drug used for the treatment of some refractory pediatric epileptic syndromes. After adding 50µL of the internal standard, which consisted of a 15mg/L solution of deuterated racemic VGB, and 100µL of water to 100µL of plasma samples, a protein precipitation was performed by adding 600µL of methanol. The supernatant was evaporated to dryness under a stream of nitrogen and the dry residue was reconstituted with 500µL of water. Then, 100µL of 0.01M o-phthaldialdehyde and 0.01M N-acetyl-l-cysteine in borate buffer (0.1M, pH=9.5) were added for pre-column derivatization of the enantiomers as diastereomeric isoindoles. One microliter of the resulting mixture was injected in the chromatographic system. The chromatographic separation was performed in gradient elution mode at a flow rate of 400µL/min using a phenomenex EVO C-18 column with a mobile phase composed of 5mM ammonium acetate and a methanol:acetonitrile (63:37v/v) mixture. Detection was performed by mass spectrometry in selected reaction monitoring mode using heated electrospray ionization in positive mode as the ion source. Intra- and inter-day precision and accuracy were lower than 15% over the calibration range (0.2-50mg/L for each enantiomer) and the method was successfully used to assess plasma concentrations of VGB in epileptic children.

ALK5 and ALK1 play antagonistic roles in transforming growth factor ß-induced podosome formation in aortic endothelial cells.

Transforming growth factor ß (TGF-ß) and related cytokines play a central role in the vascular system. In vitro, TGF-ß induces aortic endothelial cells to assemble subcellular actin-rich structures specialized for matrix degradation called podosomes. To explore further this TGF-ß-specific response and determine in which context podosomes form, ALK5 and ALK1 TGF-ß receptor signaling pathways were investigated in bovine aortic endothelial cells. We report that TGF-ß drives podosome formation through ALK5 and the downstream effectors Smad2 and Smad3. Concurrent TGF-ß-induced ALK1 signaling mitigates ALK5 responses through Smad1. ALK1 signaling induced by BMP9 also antagonizes TGF-ß-induced podosome formation, but this occurs through both Smad1 and Smad5. Whereas ALK1 neutralization brings ALK5 signals to full potency for TGF-ß-induced podosome formation, ALK1 depletion leads to cell disturbances not compatible with podosome assembly. Thus, ALK1 possesses passive and active modalities. Altogether, our results reveal specific features of ALK1 and ALK5 signaling with potential clinical implications.

ERP evidence of visualization at early stages of visual processing.

Recent neuroimaging research suggests that early visual processing circuits are activated similarly during visualization and perception but have not demonstrated that the cortical activity is similar in character. We found functional equivalency in cortical activity by recording evoked potentials while color and luminance patterns were viewed and while they were visualized with the eyes closed. Cortical responses were found to be different when imagining a color pattern vs. imagining a checkerboard luminance pattern, but the same when imagining a color pattern (or checkerboard pattern) vs. seeing the same pattern. This suggests that early visual processing stages may play a dynamic role in internal image generation, and further implies that visual imagery may modulate perception.

Adaptation to natural facial categories.

Face perception is fundamentally important for judging the characteristics of individuals, such as identification of their gender, age, ethnicity or expression. We asked how the perception of these characteristics is influenced by the set of faces that observers are exposed to. Previous studies have shown that the appearance of a face can be biased strongly after viewing an altered image of the face, and have suggested that these after-effects reflect response changes in the neural mechanisms underlying object or face perception. Here we show that these adaptation effects are pronounced for natural variations in faces and for natural categorical judgements about faces. This suggests that adaptation may routinely influence face perception in normal viewing, and could have an important role in calibrating properties of face perception according to the subset of faces populating an individual's environment.