Un anxiolytique naturel : l’hydrolysat trypsique de caséine alpha-s1 de lait bovin. Son intérêt en médecine humaine et vétérinaire

Tryptic hydrolysate from bovine milk alpha-s1 casein (THC), a natural product, contains a specific active decapeptide called alpha-casozepine which shows interesting pharmacological properties. Preclinical and clinical trials, as well as tests carried out on both humans and animals (rats, dogs, cats) demonstrated certain qualities of this hydrolysate. It shows a marked affinity for GABA-A receptors with a benzodiazepine-like profile and a tranquilizing and antistress activity associated with good tolerance characterized, in particular, by the absence of any habituation, dependence, sedation, memory impairment and toxicity. THC is a nutritional supplement (French regulatory status) which cannot be used as a substitute for psychotropes, such as benzodiazepines, in the treatment of severe anxiety and sleep disorders in respect of the medical recommendations. However, it could be effective in cases of slighter signs of these disorders. It could also be appropriate in the medical prevention and follow-up of subjects who have difficulty adapting to changes and stressful situations of daily life. An original pilot clinical trial respecting good practice and representative of the cases observed by General Practitioners (GPs) showed the interest of a global management program for benzodiazepine withdrawal. This global management program which included the use of THC opened a new application for it in general practice. As a result of a certain neuropsychiatric similarity between man and the domestic dog, we took the opportunity of presenting this natural tranquillizer in its application in both human and veterinary medicine.     

Étude des liens entre sommeil et mémoire épisodique chez le sujet jeune et âgé, et dans la maladie d’Alzheimer

Introduction

A large body of evidence indicates that sleep favors memory consolidation.

State of the art

This process would occur, mainly during slow-wave sleep, by means of a dialogue between the hippocampus and neocortical areas. Low levels of acetylcholine and cortisol are also needed to favor the transfer of memory traces toward the neocortex, where they will be stored for the long-term.

Perspectives

The aim of this article is, first, to give an overview of studies conducted in young healthy subjects and underpinning the hypothesis that sleep is involved in memory consolidation. Then, we will investigate the potential links between changes in sleep architecture and episodic memory impairment in both aging and Alzheimer's disease. Finally, we will see how these results can affect clinical practice.

Conclusion

Sleep-dependent memory consolidation is impaired both in aging and Alzheimer's disease. These findings suggest the importance of taking into account sleep when assessing memory function in patients.     

Sleep quality of medical students and relationships with academic performances

ObjectiveSleep health is a major public health concern because of its correlation with physical and mental health, and it may be particularly altered in medical students. This study aims: i) to examine the sleep characteristics of French medical students and their knowledge about basic sleep hygiene rules and; ii) to examine the correlations between sleep quality and academic performances, as well as between sleep quality and sleep knowledge.MethodsStudents from 4th, 5th and 6th years of medicine, of the Faculty of Paris Diderot, voluntarily responded to an online questionnaire including PSQI and multiple-choice quizzes (MCQ) about basic sleep hygiene rules.ResultsFrom the 177 participants, 49.7% had a poor sleep (PSQI > 5). Regarding sleep latency, 44.6% needed > 30 min to fall asleep at least once a week, 26.5% slept 6 hours or less by night, 42.4% of them qualified their sleep quality as bad or very bad. A serious lack of knowledge about basic sleep hygiene rules was observed, with an average score at the MCQ of 6.61/10, and only 31% of medical students were aware of basic good sleep habits. Significant correlations were observed between sleep efficiency and all academic mean scores (both regarding the morning, afternoon, and pooled mean scores), and between sleep disturbances and the morning mean score.ConclusionsFrench medical students have a poor sleep quality, correlating with academic performances, and present a poor knowledge of basic sleep rules. These findings are a call to improve medical training schedules and to develop prevention and training programs.     

Anxiety and sleep quality in a sample of Lebanese healthcare workers during the COVID-19 outbreak

A cross-sectional, survey based study was conducted in order to assess mental health outcomes among healthcare workers in a private university hospital involved in the COVID-19 response in Lebanon. The main objective was to quantify symptoms of anxiety and sleep quality using self-rating scales (the State-Trait Anxiety Inventory (STAI) and Pittsburgh Sleep Quality Index (PSQI) respectively), while identifying factors that might affect those symptoms. A total of 628 healthcare workers completed the survey; 409 (66.2%) were younger than 40 years, and 441 (71.4%) were women. Of all participants, 503 (81.4%) were nurses, 52 (8.4%) were physicians and 63 (10.2%) were residents. Registered nurses, residents, women, and younger participants presented higher scores on both scales than other categories of participants. Among factors related with COVID-19, those associated with higher scores were having relatives affected by the virus (22.2%), being excessively exposed to media (12.9%), and increasing the consumption of substances/alcohol (31.2%) during this period. Factors associated with higher risk of anxiety symptoms after multivariable logistic regression analysis were: female sex, young age, poor sleep quality, and living with elderly. Our findings contribute to the understanding of the psychological wellbeing of health care workers involved in the acute COVID-19 outbreak in Lebanon.     

Comments on an animal model of depression

Depression is a multifactorial illness and genetic factors play a role in its etiology. The understanding of its pathophysiology relies on the availability of experimental models potentially mimicking the disease. Here is presented a model built up by selective breeding of mice with strikingly different responses in the tail suspension test, a stress paradigm aimed at screening potential antidepressants. Indeed, "helpless" mice are essentially immobile in the tail suspension test, as well as the Porsolt forced-swim test, and they show reduced consumption of a palatable 2% sucrose solution. In addition, helpless mice exhibit sleep-wakefulness alterations resembling those classically observed in depressed patients, notably a lighter and more fragmented sleep, with an increase pressure of rapid eye movement sleep. Compared with "nonhelpless" mice, they display higher basal serum corticosterone levels and lower serotonin metabolism index in the hippocampus. Remarkably, serotonin1A autoreceptor stimulation induced greatest hypothermia and inhibition of serotoninergic neuronal firing in the nucleus raphe dorsalis in helpless than in nonhelpless mice. Thus, helpless mice exhibit a decrease in serotoninergic tone, which evokes that associated with endogenous depression in humans. Finally, both the behavioral impairments and the serotoninergic dysfunction can be improved by chronic treatment with the antidepressant fluoxetine. The helpless line of mice may provide an opportunity to approach genes influencing susceptibility to depression and to investigate neurophysiological and neurochemical substrates underlying antidepressant effects.     

Sommeil in marsupio chez le Rat-Kangourou (Potorous apicalis)

Ontogenesis of states of vigilance in marsupio was studied by polygraphic methods in Kangaroo Rat from 5 weeks. Paradoxical sleep (PS) and wakefulness activations were observed at 7 weeks; at 9–10 weeks, a state of sleep with cortical spindles, precursor of the slow-wave sleep (SWS), appeared and sleep with typical slow-waves was present only at 15 weeks; at the beginning of the 16th week, ECoG patterns of the 3 states of vigilance were adultlike. Quantitative evolution of the sleep-wakefulness cycle in marsupio was studied from the 9th to the 24th weeks. At 9 weeks, PS percentage (53%) represented almost total sleep; after this period, it decreased progressively, in correlation with the setting of SWS — an adult percentage of SWS was observed at 15–16 weeks. Finally, wakefulness percent-time stayed relatively constant, averaging about 30% between 9 and 17 weeks. A 20% increase was observed during the 18th and 19th weeks after birth, when young was definitely rejected from the marsupium. Ontogenesis of sleep in marsupio followed the same general rules of maturation already described in Eutheriens. But it presented two typical characteristics: its slowness of maturation and the particular evolution of wakefulness during the period of voluntary fixation on the mammal. Importance of environmental conditions on the development of sleep-wakefulness cycle was discussed.