Ultradian oscillations in plasma renin activity: their relationships to meals and sleep stages.

The 24-h pattern of PRA was studied in 6 supine normal subjects, and the relationship between sleep stages and PRA oscillations was analyzed using 18 nighttime profiles and the concomitant polygraphic recordings of sleep. Blood was collected at 10-min intervals. The slow trends obtained by adjusting a third degree polynomial to the 24-h data were not reproducible among individuals, and no circadian pattern was detected. Sustained oscillations in PRA occurred throughout the day. Spectral analysis revealed that PRA oscillated at a regular periodicity of about 100 min during the night. This periodicity was modified during the daytime by meal intake, which induced PRA peaks with large interindividual variations in size. A close relationship was found between the nocturnal PRA oscillations and the alternance of rapid eye movement (REM) sleep and non-REM sleep. Non-REM sleep invariably coincided with increasing or peaking PRA levels. REM sleep occurred as PRA was declining or at nadirs. More precisely, increases in PRA marked the transition from REM sleep to stage II, whereas stages III and IV usually occurred when PRA was highest. This relationship between the periodic nocturnal oscillations in PRA and the alternance of the REM-non-REM cycles may translate a similar oscillatory process in the central nervous system or may be linked to hemodynamic changes during sleep that might be partly controlled by the renin-angiotensin system.

K-complexes and sleep spindles before transient activation during sleep.

Six subjects spent three consecutive nights in the sleep laboratory. Activation phases (PATs), spontaneous K-complexes, and sleep spindles were visually detected in sleep stages 2 and 3 for nights 2 and 3. The K-complex rate was significantly greater in the 10 sec prior to the PATs than at any other time spent in stage 2 or 3. K-complexes associated with sheep spindles occurred significantly less frequently during the epochs just preceding the PATs. In all subjects, there was a sharp increase of sleep spindles associated with K-complexes when PATs did not follow within 10 sec. These results suggest that spontaneous K-complexes and sleep spindles act antagonistically with respect to the occurrence of PATs. These two phasic events are significantly related to regulating the probability of occurrence of PATs in sleep stages 2 and 3; K-complexes may reflect an organismic state leading towards PAT, whereas sleep spindles may inhibit the occurrence of PAT.

[Socioprofessional consequences of Crohn disease]. / Répercussions socio-professionnelles de la maladie de Crohn.

To evaluate evolutivity and social repercussions of Crohn's disease, the same gastroenterologist interviewed 151 out of 197 patients with Crohn's disease (77.5 percent) who had been hospitalized from 1964 to 1986 in our unit. The other 46 could not be traced or refused to participate. There was no difference regarding age, sex, duration of illness, pattern of lesions and operations between the two groups. At the time of observation, mean follow-up was 7.8 years and two thirds of the patients had inactive disease. During the previous year, the course of the disease was quiescent in 50 percent of all patients; this rate increased with duration of follow-up and time from surgery. A constant rate of stable course was observed (20 percent) irrespective of duration of disease and time of surgery. The interviews were compared with those obtained from an age and sex-matched group of 70 previously healthy subjects admitted to the hospital for less than one month. The education and socioeconomic levels were higher in patients with Crohn's disease than in controls, in spite of the fact that 25 percent of patients whose disease begun during scholarship complained of difficulties at school, and nearly 20 percent of all patients were partially or totally unable to work. Sports and cultural activities were the same in Crohn's disease and in the control group. Tobacco intake was slightly higher at time of diagnosis but it was equal in both groups at the time of the interview. Non allopathic advice or treatment were sought by 48 percent of Crohn's disease patients (7 percent in controls).(ABSTRACT TRUNCATED AT 250 WORDS)

Characteristics of rapid eye movement production during REM sleep in man: organization and rhythmicity.

The purpose of this study was to verify statistically the existence of certain characteristics of rapid eye movement (REM) production during REM sleep: organization and rhythmicity. REM data were collected intermittently, over a period of 20 consecutive nights, from 6 normal adult subjects of both sexes. Results concerning the organization of REM production revealed the presence of 3 evolving slow trends: quadratic, linear and quasi-sinusoidal. The occurrence of a given trend type was not related to subject, night, time of night or length of REM sleep phase being analysed. Results of the analysis showed that it is possible for a series of REMs to contain one, two or more statistically significant rhythmic periods, or no significant rhythmic period. The rhythmic periods that were detected ranged from 1 to 21 min, and no predominant periods were present. As in the case of the slow trends, the occurrence of a given rhythmic period was not dependent on subject, night, time of night or length of the REM sleep phase.