Diet induced weight loss accelerates onset of negative alliesthesia in obese women

BACKGROUND: The physiological and behavioral responses to hypocaloric diet are to increase energy intake to defend a steady body weight. We utilized the method of "negative alliesthesia" for measuring the hedonic reponse to sweet stimulus before (Initial session) and 3 months after entering a weight loss program. The negative alliesthesia test is known by physiologists but few clinical data exist. It is based on the observation that repeated pleasant gustatory stimuli turn into unpleasantness in the process of alliesthesia. At first visit participants repeatedly ingested sweet stimuli until they found them unpleasant and rated quantitatively on a linear analogue scale their hedonic experience. This procedure was repeated every 3 min until participants felt displeasure to end the session. The same protocol was followed after three months of following a weight loss diet. Dieting energy intake was from 1400 – 2000 kcal/d for 8 wk. Energy composition was 50% carb:25% prot: 25% lipid. After 8 wk caloric intake increased by 50 kcal/wk, to reach daily intake of 1800 – 2400 kcal/d. Energy composition was 50% carb:22% prot: 27% lipid. We report results on the effect of slow weight loss on negative alliesthesia in ten obese female participants enrolled in a commercial diet program based on Canada's Food Guide (Mincavi(®)). RESULTS: Results showed that diet lowered the mean BMI (Initial session 36.8 +/- 1.8 vs. 3 mo 34.9 +/- 1.8 kg/m(2)). At 3 mo the onset of negative alliesthesia, time to abandon experimental session, was shortened (Initial session 33 vs. 3 mo 24 min). The same trend was observed in the time to reach indifference (Initial session 21.9 +/- 3.8 vs. 3 mo 16.2 +/-2.4 min). There was no observed difference in maximum (Initial session +79.5 +/- 11.7; 3 mo +94.5 +/- 9.9 mm) and minimum (Initial session -90.0 +/- 14.4; 3 mo -106 +/- 11.1 mm) hedonic rating. CONCLUSION: Earlier onset of negative alliesthesia, as seen in our participants, is not consistent with previous hedonic studies that showed delayed or absent negative alliesthesia in participants when below their initial body weight. Therefore, it is hypothesized that the accelerated onset of negative alliesthesia observed in our obese participants after weight loss is suggestive of a lowered body weight set-point. Factors inherent to the weight loss diet studied here, such as mild energetic restriction, lowered palatability, and diet composition, may have played a role in this experimental outcome

Mixed bag “polypharmacy”: methodological pitfalls and challenges of this exposure definition

Purpose of Review The use of multiple medications is common in older adults but is associated with negative health outcomes. However, polypharmacy is not uniformly defined, and there is scant data on how the variety of definitions and their limitations hinder the development of sound scientific knowledge. The article intends to illustrate the challenges of this exposure definition. Recent Findings The array of thresholds for defining polypharmacy renders comparisons between results difficult. Few studies take into account the fact that polypharmacy is a changing exposure over time. In addition, although studies tend to recognize the confounding effect of multimorbidity, residual bias remains a concern. Summary Current studies in polypharmacy often ignore basic epidemiological principles for defining exposure. Future research should integrate time-varying exposure and methods to better control confounding bias. This will help determine the positive/negative impacts of polypharmacy and help establish if polypharmacy conveys information beyond being a marker of health status

Regional cerebral blood flow during wakeful rest in older subjects with mild to severe obstructive sleep apnea

Objectives: To evaluate changes in regional cerebral blood flow (rCBF) during wakeful rest in older subjects with mild to severe obstructive sleep apnea (OSA) and healthy controls, and to identify markers of OSA severity that predict altered rCBF. Design: High-resolution 99mTc-HMPAO SPECT images during wakeful rest. Setting: Research sleep laboratory affiliated with a University hospital. Participants: Fifty untreated OSA patients aged between 55 and 85 years divided into mild, moderate and severe OSA and 20 age-matched healthy controls. Interventions: N/A Measurements: Using statistical parametrical mapping, rCBF was compared between groups and correlated with clinical, respiratory and sleep variables. Results: Whereas no rCBF change was observed in mild and moderate groups, participants with severe OSA had reduced rCBF compared to controls in the left parietal lobules, precentral gyrus, bilateral postcentral gyri, and right precuneus. Reduced rCBF in these regions and in areas of the bilateral frontal and left temporal cortex was associated with more hypopneas, snoring, hypoxemia, and sleepiness. Higher apnea, micro-arousal, and body mass indexes were correlated to increased rCBF in the basal ganglia, insula, and limbic system. Conclusions: While older individuals with severe OSA had hypoperfusions in the sensorimotor and parietal areas, respiratory variables and subjective sleepiness were correlated with extended regions of hypoperfusion in the lateral cortex. Interestingly, OSA severity, sleep fragmentation and obesity correlated with increased perfusion in subcortical and medial cortical regions. Anomalies with such a distribution could result in cognitive deficits and reflect impaired vascular regulation, altered neuronal integrity, and/or undergoing neurodegenerative processes

Parallel recovery of consciousness and sleep in acute traumatic brain injury.

OBJECTIVE: To investigate whether the progressive recuperation of consciousness was associated with the reconsolidation of sleep and wake states in hospitalized patients with acute traumatic brain injury (TBI). METHODS: This study comprised 30 hospitalized patients (age 29.1 ± 13.5 years) in the acute phase of moderate or severe TBI. Testing started 21.0 ± 13.7 days postinjury. Consciousness level and cognitive functioning were assessed daily with the Rancho Los Amigos scale of cognitive functioning (RLA). Sleep and wake cycle characteristics were estimated with continuous wrist actigraphy. Mixed model analyses were performed on 233 days with the RLA (fixed effect) and sleep-wake variables (random effects). Linear contrast analyses were performed in order to verify if consolidation of the sleep and wake states improved linearly with increasing RLA score. RESULTS: Associations were found between scores on the consciousness/cognitive functioning scale and measures of sleep-wake cycle consolidation (p < 0.001), nighttime sleep duration (p = 0.018), and nighttime fragmentation index (p < 0.001). These associations showed strong linear relationships (p < 0.01 for all), revealing that consciousness and cognition improved in parallel with sleep-wake quality. Consolidated 24-hour sleep-wake cycle occurred when patients were able to give context-appropriate, goal-directed responses. CONCLUSIONS: Our results showed that when the brain has not sufficiently recovered a certain level of consciousness, it is also unable to generate a 24-hour sleep-wake cycle and consolidated nighttime sleep. This study contributes to elucidating the pathophysiology of severe sleep-wake cycle alterations in the acute phase of moderate to severe TBI

L’enseignement universitaire des réalités autochtones dans les cours en sciences de la santé : un examen de la portée

Introduction&nbsp;: Pour répondre à l’appel à l’action #24 de la Commission de vérité et de réconciliation du Canada (2015), les étudiants des écoles de médecine et de sciences infirmières devraient suivre un cours sur les questions liées à la santé des Autochtones. Plusieurs enseignants expriment un inconfort à le faire, alors que la préparation des étudiants pour intervenir auprès d’une clientèle autochtone est essentielle. Méthodes&nbsp;: L’objectif de cet examen de la portée est de brosser un portrait des stratégies pédagogiques utilisées pour l’enseignement universitaire des réalités autochtones en sciences de la santé. La démarche de Arksey et O’Malley (2005) a été utilisée et cinq études ont été retenues à partir des bases de données Education Source, ERIC, CINAHL, Medline et PsychInfo. Les critères d’inclusion pour les études étaient d’être une recherche primaire, en anglais ou en français et publiée entre 2001 et 2021. Résultats&nbsp;: Parmi les cinq études retenues, quatre proviennent du Canada et une d’Australie. Elles ont toutes été rédigées en anglais. Les résultats des études indiquent un grand niveau d’apprentissage et une satisfaction élevée des participants pour ces stratégies pédagogiques développées en collaboration avec des Autochtones, tels que des ateliers, un stage ou encore un exercice immersif. Discussion et conclusion&nbsp;: Un changement de perspectives envers les Autochtones et une meilleure compétence culturelle pour intervenir avec eux ont été observés, ainsi qu’un désir d’action sociale sur la réconciliation. Les stratégies pédagogiques utilisées pour l’enseignement universitaire des réalités autochtones en sciences de la santé sont encore peu documentées, malgré les impacts positifs qu’elles apportent aux étudiants et son importance dans le processus de réconciliation.Introduction&nbsp;: Pour répondre à l’appel à l’action #24 de la Commission de vérité et de réconciliation du Canada (2015), les étudiants des écoles de médecine et de sciences infirmières devraient suivre un cours sur les questions liées à la santé des Autochtones. Plusieurs enseignants expriment un inconfort à le faire, alors que la préparation des étudiants pour intervenir auprès d’une clientèle autochtone est essentielle. Méthodes&nbsp;: L’objectif de cet examen de la portée est de brosser un portrait des stratégies pédagogiques utilisées pour l’enseignement universitaire des réalités autochtones en sciences de la santé. La démarche de Arksey et O’Malley (2005) a été utilisée et cinq études ont été retenues à partir des bases de données Education Source, ERIC, CINAHL, Medline et PsychInfo. Les critères d’inclusion pour les études étaient d’être une recherche primaire, en anglais ou en français et publiée entre 2001 et 2021. Résultats&nbsp;: Parmi les cinq études retenues, quatre proviennent du Canada et une d’Australie. Elles ont toutes été rédigées en anglais. Les résultats des études indiquent un grand niveau d’apprentissage et une satisfaction élevée des participants pour ces stratégies pédagogiques développées en collaboration avec des Autochtones, tels que des ateliers, un stage ou encore un exercice immersif. Discussion et conclusion&nbsp;: Un changement de perspectives envers les Autochtones et une meilleure compétence culturelle pour intervenir avec eux ont été observés, ainsi qu’un désir d’action sociale sur la réconciliation. Les stratégies pédagogiques utilisées pour l’enseignement universitaire des réalités autochtones en sciences de la santé sont encore peu documentées, malgré les impacts positifs qu’elles apportent aux étudiants et son importance dans le processus de réconciliation

Sleep and wake disturbances following traumatic brain injury

Traumatic brain injury (TBI) is a major health concern in industrialised countries. Sleep and wake disturbances are among the most persistent and disabling sequelae after TBI. Yet, despite the widespread complaints of post-TBI sleep and wake disturbances, studies on their etiology, pathophysiology, and treatments remain inconclusive. This narrative review aims to summarise the current state of knowledge regarding the nature of sleep and wake disturbances following TBI, both subjective and objective, spanning all levels of severity and phases postinjury. A second goal is to outline the various causes of post-TBI sleep-wake disturbances. Globally, although sleep-wake complaints are reported in all studies and across all levels of severity, consensus regarding the objective nature of these disturbances is not unanimous and varies widely across studies. In order to optimize recovery in TBI survivors, further studies are required to shed light on the complexity and heterogeneity of post-TBI sleep and wake disturbances, and to fully grasp the best timing and approach for intervention

Wheat Bran Pretreatment by Room Temperature Ionic Liquid-Water Mixture: Optimization of Process Conditions by PLS-Surface Response Design

International audienceRoom Temperature Ionic Liquids (RTILs) pretreatment are well-recognized to improve the enzymatic production of platform molecules such as sugar monomers from lignocellulosic biomass (LCB). The conditions for implementing this key step requires henceforth optimization to reach a satisfactory compromise between energy saving, required RTIL amount and hydrolysis yields. Wheat bran (WB) and destarched wheat bran (DWB), which constitute relevant sugar-rich feedstocks were selected for this present study. Pretreatments of these two distinct biomasses with various 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc])-water mixtures prior to hydrolysis catalyzed by hemicellulolytic cocktail (Cellic CTec2) were finely investigated. The main operating conditions such as pretreatment temperature (25–150°C), time (40–180 min), WB and DWB loading (2–5% w/v) and concentration of [C2mim][OAc] in water [10–100% (v/v)] were screened through glucose and xylose yields and then optimized through a Partial Least Square (PLS)—Second Order Design. In an innovative way, the PLS results showed that the four factors and their interactions could be well-fitted by a second-order model (p < 0.05). The quadratic PLS models were used to predict optimal pretreatment conditions. Thus, maximum glucose (83%) and xylose (95%) yields were obtained from enzymatic hydrolysis of WB pretreated at 150°C for 40 min with 10% of [C2mim][OAc] in water and 5% of WB loading. For DWB, maximum glucose (100%) and xylose (57%) yields were achieved for pretreatment temperatures of 150°C and 25°C, respectively. The required duration was still 40 min, with 20% of [C2mim][OAc] in water and a 5% DWB loading. Then, Multiple Response Optimization (MRO) performed by Nelder-Mead Simplex Method displayed sugar yields similar to those obtained by individual PLS optimization. This complete statistical study confirmed that the established models were appropriate to predict the sugar yields achieved after different pretreatment conditions from WB and DWB biomasses. Finally, Scanning Electron microscopy (SEM) studies allowed us to establish clearer link between structural changes induced by pretreatment and the best enzymatic performances obtained

The eyes are not the window to basic emotions

a b s t r a c t Facial expressions are one of the most important ways to communicate our emotional state. In popular culture and in the scientific literature on face processing, the eye area is often conceived as a very important -if not the most important -cue for the recognition of facial expressions. In support of this, an underutilization of the eye area is often observed in clinical populations with a deficit in the recognition of facial expressions of emotions. Here, we used the Bubbles technique to verify which facial cue is the most important when it comes to discriminating between eight static and dynamic facial expressions (i.e., six basic emotions, pain and a neutral expression). We found that the mouth area is the most important cue for both static and dynamic facial expressions. We conducted an ideal observer analysis on the static expressions and determined that the mouth area is the most informative. However, we found an underutilization of the eye area by human participants in comparison to the ideal observer. We then demonstrated that the mouth area contains the most discriminative motions across expressions. We propose that the greater utilization of the mouth area by the human participants might come from remnants of the strategy the brain has developed with dynamic stimuli, and/or from a strategy whereby the most informative area is prioritized due to the limited capacity of the visuo-cognitive system

Brain white matter damage and its association with neuronal synchrony during sleep

The restorative function of sleep partly relies on its ability to deeply synchronize cerebral networks to create large slow oscillations observable with EEG. However, whether a brain can properly synchronize and produce a restorative sleep when it undergoes massive and widespread white matter damage is unknown. Here, we answer this question by testing 23 patients with various levels of white matter damage secondary to moderate to severe traumatic brain injuries (ages 18–56; 17 males, six females, 11–39 months post-injury) and compared them to 27 healthy subjects of similar age and sex. We used MRI and diffusion tensor imaging metrics (e.g. fractional anisotropy as well as mean, axial and radial diffusivities) to characterize voxel-wise white matter damage. We measured the following slow wave characteristics for all slow waves detected in N2 and N3 sleep stages: peak-to-peak amplitude, negative-to-positive slope, negative and positive phase durations, oscillation frequency, and slow wave density. Correlation analyses were performed in traumatic brain injury and control participants separately, with age as a covariate. Contrary to our hypotheses, we found that greater white matter damage mainly over the frontal and temporal brain regions was strongly correlated with a pattern of higher neuronal synchrony characterized by slow waves of larger amplitudes and steeper negative-to-positive slopes during non-rapid eye movement sleep. The same pattern of associations with white matter damage was also observed with markers of high homeostatic sleep pressure. More specifically, higher white matter damage was associated with higher slow-wave activity power, as well as with more severe complaints of cognitive fatigue. These associations between white matter damage and sleep were found only in our traumatic brain injured participants, with no such correlation in controls. Our results suggest that, contrary to previous observations in healthy controls, white matter damage does not prevent the expected high cerebral synchrony during sleep. Moreover, our observations challenge the current line of hypotheses that white matter microstructure deterioration reduces cerebral synchrony during sleep. Our results showed that the relationship between white matter and the brain’s ability to synchronize during sleep is neither linear nor simple