0133 NLRP3 Inflammasomes Modulate Brain Vasohemodynamic Responses to Sleep Loss

Introduction

Increased cerebral blood flow (CBF) is positively associated with non-rapid eye movement (NREM) sleep electroencephalogram (EEG) delta power, also known as slow-wave activity (SWA). The pro-inflammatory somnogenic cytokine interleukin-1 beta (IL-1β) can induce vasodilation and increase CBF. Nucleotide leucine-rich protein complex-3 (NLRP3) inflammasomes, which activate IL-1β, are increased in the cortex after sleep deprivation and increase SWA. We aimed to determine the relationship of NLRP3 inflammasomes on sleep loss-induced alterations in vasohemodynamics and SWA.

Methods

NLRP3 knock-out (KO) and wild-type (WT) mice underwent ad libitum sleep, 6 hours of sleep deprivation, or were given 10 ng of IL-1β or the vehicle intracerebroventricularly. SWA and CBF, blood velocity, and blood volume were determined concurrently during sleep/wake states using polysomnography and laser doppler flowmetry. Regional brain changes in CBF were determined using transponders, spectrophotometry, and fluorescent microspheres.

Results

SWA and CBF were significantly increased during the first 6 hours after sleep deprivation in WT but not NLRP3 KO mice. SWA and CBF significantly increased in the first 6 hours after IL-1β in both NLRP3 KO and WT mice. Additionally, alterations in cerebral blood velocity and volume demonstrated state specific changes that varied significantly during the transitions between states. SWA and CBF were significantly positively correlated during both ad libitum sleep and sleep after sleep deprivation in WT mice, although this relationship was not observed in NLRP3 KO mice. We also found significant phase-amplitude frequency coupling between SWA and CBF. Cortical changes CBF were significantly enhanced after sleep deprivation and IL-1β administration in WT mice, although were attenuated in the hypothalamus. NLRP3 KO mice showed these same regional effects in CBF after IL-1β but not sleep deprivation.

Conclusion

Our findings indicate that NLRP3 inflammasomes are involved in neurovascular coupling involving SWA.

Support

Department of Veterans Affairs IBX002823A (MRZ)

Alteration and release of aliphatic compounds by the polychaete Nereis virens (Sars) experimentally fed with hydrocarbons

In the laboratory, marine worms were fed with a mixture of algae and several aliphatic hydrocarbons for 15 days. After ingestion by the worms, 34.9% of hydrocarbons are found in the faeces and only 3.1% accumulated in the gut. The comparison between the initial mixture and the faeces shows that the worm's digestive process lead to changes in the distribution of the n-alkane mixture. These changes are different from those only due to physical processes in the experimental conditions. In our experiment, no variation in the distribution of hydrocarbons in faeces with time and no microbial hydrocarbon biodegradation were evidenced. Our results suggest that marine worm feeding can substantially affect the fate of hydrocarbons in the sedimentary marine ecosystem by predominantly stimulating dissolution processes.

[Government health activities between 1922 and 1936]

The 75th birthday of the Service provincial d'hygiène was commemorated in 1997. However we do not have a comprehensive history of this Service which succeeded the Conseil supérieur d'hygiène of the Province of Quebec (1887) and which eventually led to the institution of the Ministry of Health in 1936. Yet there have been significant changes in the field of public health in Quebec between 1921 and 1936, the period during which the Service provincial d'hygiène operated. We will show that through this organization, the Province played an essential role in establishing the first public health system and commencing the process of rnedicalization of the society. By 1919, federal intervention was added to provincial intervention through the establishment of the Federal Ministry of Health. But what was the structure of this provincial public health organization? How did it function? What resources did it have at its disposal to put in place a health and prevention policy? Although some recent studies have addressed the question of the appearance of a health policy at that time, there is still no analysis on the structure of this state sanitary agency, nor on its organization, functions, and means of actions. This study presents an example of the thesis adopted by the authors in previous works -i.e. that the historical vision of an unchanging health system in a static Quebec society before the Quiet Revolution must be rectified- it must also challenge the idea that, absent from this field, the state would not have adopted a health policy due to its own inertia or to the resistance of "liberal" forces and the opposition of the clergy.

Participation in CME activities

OBJECTIVE

To compare the continuing medical education (CME) activities of family physicians in the province of Quebec with more than 25 years in practice with those with less than 25 years in practice.

DESIGN

Mailed questionnaire survey.

SETTING

Family practices in the province of Quebec.

PARTICIPANTS

All physicians (n = 722) with more than 25 years in practice (expressed as older) and a matched sample of 721 physicians with less than 25 years in practice (expressed as younger).

MAIN OUTCOME MEASURES

Types of CME activities and time spent on them, participant characteristics.

RESULTS

Older physicians spent more time in individual CME activities than younger ones (21 hours vs 18 hours monthly). Younger physicians, however, spent more time in group CME activities than older ones did (100 hours vs 80 hours yearly). Excluding physicians who devoted no time to CME activities, only two activities differentiated between the two groups: older physicians spent more time than their younger colleagues reading and listening to audiocassettes.

CONCLUSIONS

Older physicians maintained their clinical competence by participating in different CME activities from younger physicians. They participated in as many CME activities as their younger colleagues.

[Joseph-Albert Baudoin (1875-1962): professor of hygiene]

L'histoire de la carrière professionnelle du docteur Baudoin permet de suivre l'émergence et le développement de la profession de médecin hygiéniste au Québec francophone et de connaître son idéologie, son corps de connaissance, ses pratiques, son organisation professionnelle et ses liens avec le milieu social ambiant, notamment avec le milieu universitaire où s'est déroulée la plus grande partie de sa carrière.

Organization of Fighting in the Polychaete Nereis Virens (Sars) and the Effects of Residency and Orientation

Abstract

Intraspecific encounters of the polychaete Nereis virens (Sars) were studied within artificial burrows in order to describe behavioural interactions that occur during the defence of the burrow. This work exploited the relationship between variability in contest outcomes and fighting behavioural sequences as a function of different types of encounters. In addition, the effects of resident orientation, duration of resident occupancy (acclimatization) and initial distance of the intruder anterior end from the resident (head or tail) were all included. The eviction frequency was significantly greater in the presence of acclimated individuals. Acclimatization reduced chances of cohabitation between two individuals within the same burrow. However, the importance of the acclimatization was greater in head to head ("H-H") encounters as opposed to head to tail("H-T") encounters. Encounters within a 15 cm distance separating each individuals showed that intruders were expelled in all "H-H" cases (100%) in contrast to 32% in "H-T" encounters. No significant difference was noticed between "H-H" and "H-T" encounters where the initial distance was greater than 15 cm. Fights were settled, on average, in 10 minutes with acclimated individuals in contrast to less than 2 minutes with non-acclimated worms. Behavioural sequences, for agonistic encounters, were more complex in residents than for intruders. Complexity in patterns was also greater for non-acclimated worms.

Évolution spatio-temporelle du réseau de galeries chez le polychète Nereis virens (Sars) en relation avec la densité

In burrowing species, burrowing behaviour sometimes gives rise to the establishment of a territory. The spatio–temporal evolution of tunnels in the Polychaete Nereis virens (Sars) allowed us to study space allocation between individuals under two conditions of population density. During the first 3 days, a behaviour of exploration–construction within the substrate is observed. At that point, the tunnel has many branches and is a complex system of ramifications. On the 7th day, the system is simplified. The fluctuations of the various structural parameters of the burrow indicate alternating phases of activity in the animal. The shape and size of the burrow are density dependent. When the density is low, the burrow is U-shaped, whereas it is I-, L-, or Y-shaped at high density. The structure of the burrows, as observed in resin casts in the laboratory, and the absence of connections between the burrows indicate the onset of a territorial behaviour within the sediment right at the beginning of construction.[Journal translation]

Health profile of applicants for refugee status (admitted into Quebec between August 1985 and April 1986)

Refugees requesting asylum when in Canada are termed "Applicants for Refugee Status". The present epidemiological study of a large series of these refugees by the Community Health Department of St-Luke's Hospital in Montreal provides a picture of their social and health profiles. The refugees came from developing countries with serious internal conflicts. On the whole, their state of health was satisfactory. However, in some cases specific diseases were detected which were often connected with their geographical origin. These diseases, which included treponematosis, intestinal parasitosis and nutritional deficiency should in future give rise to health care programs specially adapted to the sub-populations concerned. As regards the problem of torture, both its underestimation and inadequate psychological follow-up among refugees are of great concern and call for special training in treating the effects of torture on its victims.

[Not Available]

L'enseignement universitaire spécialisé de santé publique (distinct de l'enseignement de santé publique donné dans les formations générales de base aux médecins et infirmières) a commencé au Québec en 1899. Les auteurs étudient les structures d'organisation qui lui ont servi de cadre jusqu'en 1970, date qui a 6té le point de départ de changements radicaux dans ces structures, puisqu'on a aboli l'école spécialisée de santé publique et qu'on a intégré son enseignement dans les facultés de médecine et de sciences infirmières. Les auteurs commencent par présenter l'hypothèse qu'ils ont formulée pour comprendre la naissance de cet enseignement et les transformations intervenues durant la période. Ils avancent l'idée que les institutions de formation dans le domaine de l'enseignement spécialisé de santé publique sont liées beaucoup plus directement aux pratiques effectives de santé publique du moment, vaccination, éducation sanitaire, et à l'utilité que la société leur reconnaît qu'à une dynamique interne du système d'enseignement universitaire médical. Elles sont donc dépendantes dans leurs transformations historiques surtout de déterminants externes dont il faut cerner et mesurer les effets. Dans un deuxième temps, les auteurs présentent une typologie des organismes qui ont eu la responsabilité de cet enseignement ainsi que des programmes offerts et des catégories de professionnels qui ont été formés. Dans un troisième temps, I ils étudient les différentes étapes des transformations intervenues et en analysent les facteurs déterminants à partir de l'hypothèse formulée au départ.

Comparaison de critères utilisables pour l'étude de la structure des populations du polychète Nereis virens (Sars)

The various biometrical criteria used in the study of the population structure of the annelid polychaete Nereis virens (Sars) are reviewed. This type of study, which requires the examination of large numbers of specimens representing all size classes, is sometimes complicated by the occurrence of autotomy, a phenomenon quite frequent in this species, and by mechanical breaks during sampling and sieving. Measurements such as total length, width of an anterior segment, and total weight are not good criteria. We have used a new biometrical criterium developed at the Laboratoire maritime de Dinard (France). This criterium is based on a partial weight of animals that have been put in formaldehyde and wiped; the weight is determined from an histogram in which breaking points are "ranked". This ponderal measurement has been compared with the linear measurement of the jaw length. The new method allows the manipulation of a larger number of individuals and it is easier and faster to use than the method based on jaw measurements.[Journal translation]