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Biomedical subjects

A Buguet

Publications and source records attributed to A Buguet.

At least 73 records · Page 4Linked to original sources
PubMed1992

Study of evoked potentials in human African trypanosomiasis.

Human African trypanosomiasis or sleeping sickness has a stage of neurological involvement characterized by the onset of diffuse meningoencephalitis with sleep disturbances and decreased wakefulness. The pathogenesis of this disease is not well understood. We studied auditory, visual, sensory, and motor evoked potentials in 16 patients with trypanosomiasis in the early stage of meningoencephalitis. In all patients, the brain-stem auditory evoked response (BAER) and the pattern-reversal visual evoked response (PVER) were normal. On the other hand, abnormalities of the somatosensory evoked response (SSER) or the motor evoked response (MER) were found in only five cases; however, their relationship to the illness could not be definitely confirmed. The study results indicate that the evaluated pathways were essentially intact, in particular at the level of the brain-stem in the early stage of the disease. Sleep disturbances and decreased wakefulness noted at this stage were thus linked more closely to functional involvement at the level of the sleep centres than to any detectable specific anatomic lesion.

Adolescent↗
PubMed1990

Thermal exchanges during sleep in anhidrotic ectodermal dysplasia.

Anhidrotic ectodermal dysplasia is a congenital syndrome characterized by the absence of sweat glands. A sweating test was performed on such a patient and proved his inability to sweat. Thermal exchanges during night sleep were then measured in this patient and compared with data obtained from a healthy control subject. Ambient conditions were as follows: dry bulb temperature 32.2 degrees C, relative humidity 30%-40%, wind speed 0.7 m.s-1. Polysomnographic recordings showed normal sleep patterns in both subjects, but a "first night effect" in the patient. Rectal (Tre) and mean skin (Tsk) temperatures and loss of mass were monitored continuously throughout the 8-h sleep recording. Loss of mass averaged 34.1 g.h-1 in the patient vs 78.1 g.h-1 in the control subject. No relationship with sleep stages was observed in the patient, in contrast to the control subject who experienced a decrease in evaporation during rapid eye movement sleep. Body temperatures varied little in the patient, but decreased until the 6th h of sleep in the control subject. On two occasions there was a 0.3 degrees C fall in the Tre of the patient during two slow wave sleep (SWS) phases, while Tsk and loss of mass did not change. As thermolytic processes had not varied on these two occasions, it was concluded that the fall in Tre indicated a concomitant decrease in metabolic heat production, in agreement with the assumption that SWS represented a state of energy conservation.

Adolescent↗
PubMed1990

[Circadian analysis of sleep, rectal temperature and immunological and endocrinological variables in sleeping sickness: preliminary study].

A multidisciplinary study was conducted in 8 patients with neurological Human African Trypanosomiasis. The sleep-wake cycle followed an ultradian pattern which was more pronounced in patients with more severe symptoms. The EEG trace was consistently interrupted by numerous cyclic activation patterns with K complexes, rapid low amplitude elements and slow high voltage elements. Circadian rhythmicity was also disturbed in other physiological (rectal temperature), immunological (interleukins) or hormonal (cortisol, prolactin) variables, the disturbance being greater in severely hit patients.

Adolescent↗
PubMed1990

[Transitory eye pain during sleep].

Transitory eye pain occurred during sleep in a 62 year-old patient, who complained of being often awoken during the second half of the night. Diurnal ophthalmologic examinations did not reveal any abnormality. Three consecutive nocturnal polysomnographic recordings were performed to determine whether these pain crises were related to any sleep stage. The patient woke up three times during the recordings because of the usual pain occurrence. On the three occasions, the crisis occurred during of immediately after a REM sleep phase. The brievity of the pain episode (4 to 5 min) did not allow a quick eye pressure measurement to demonstrate a possible increase in ocular tension. However, the role of the REM sleep myosis and vegetative manifestations are discussed regarding the determination of eye pain.

Electroencephalography↗
PubMed1989

24 hour polysomnographic evaluation in a patient with sleeping sickness.

A 24 h polysomnographic recording was performed in a patient with sleeping sickness presenting an atypical neurological syndrome. Trypanosoma gambiense was found in a lymph gland puncture and the CSF, and a serologic immunofluorescence test was positive. The scoring technique of the polygraphic traces had to be adapted because of the presence of a permanent EEG delta wave activity during the NREM sleep stages, and the method used by Schwartz and Escande (1970) was applied. REM sleep and wakefulness presented normal polygraphic characteristics. The patient had 8 sleep episodes throughout the recording period, occurring during the daytime and at night, forming the classical diurnal sleepiness and nocturnal restlessness of sleeping sickness. All but one episode represented 1-3 complete REM-NREM sleep cycles. On all occasions, REM latency was short and 2 SOREM episodes were observed. The nychthemeral organization of the stages of vigilance differed from one state to another. Wakefulness and REM sleep had a circadian rhythmicity, while NREM sleep, total sleep time and deep sleep (corresponding to stages 3 and 4) had an ultradian periodicity. The concordance between the higher pressure for wakefulness and lower pressure for sleep around 20.00 h defined the time of occurrence of a 'forbidden zone' for sleep.

Animals↗
PubMed1988

Seasonal changes in circadian rhythms of body temperatures in humans living in a dry tropical climate.

Seven volunteers (3 females and 4 males; 3 Caucasians and 4 Africans) participated in two 24 h sessions during the cool dry (CD) and the hot dry (HD) seasons of the sahelian tropical climate. Body temperatures were taken on portable cassette recorders for 24 h. Rectal (Tre) and mean skin (Tsk) temperatures decreased in the HD compared to the CD conditions, meeting one of the criteria for adaptation to heat. No ethnic differences in thermal responses were found. Males and females differed in their body temperature rhythms and in their reactions to heat. Body temperatures were higher in females than in males. Males reacted to heat with a decrease in Tre, without change in the Tre-Tsk gradient. Females showed a decrease in both Tre and Tsk, more marked for Tsk, with an increase in the Tre-Tsk gradient. It was concluded that males showed seasonal acclimatization to heat via a decrease in metabolism confirmed by a decrease in plasma levels of thyroid stimulating hormone (TSH) in the HD condition. Females showed a mixed metabolic and thermolytic type of acclimatization, with an absence of variation in plasma TSH levels. In conclusion, the steady rise in temperature between the CD and HD conditions was sufficient to trigger an acclimatization to heat similar in Caucasian and African subjects, although exposure to the external climate differed widely.

Acclimatization↗
PubMed1987

Human sleep patterns in Antarctica.

Eight volunteers wintering in a French coastal station in Antarctica underwent 156 polysomnographic night recordings. The subjects, selected for their usual good sleeping habits, were recorded on 17-21 nights throughout the wintering in sessions of 2 to 3 consecutive nights. A two-way analysis of variance showed that most of the subjects' sleep characteristics were not similar, leading the authors to study the individual time course of sleep variables. As the subjects slept in their own comfortable quarters, there was no "polar insomnia," no first night effect, nor any relationship between sleep pattern variations and climatic changes. In all subjects, delta sleep tended to increase throughout the wintering, whereas stages 1 and 2 decreased. No significant variation was seen in paradoxical sleep (PS), neither between subjects nor with time. PS latency was also within normal range, but it was bimodally distributed in subjects S1, S2, and S8. Some other sleep variables also varied in certain subjects. Such was the case for sleeping time, which decreased throughout the wintering period in subject S8, the least adapted individual. However, due to the limited number of subjects, no statistical attempt could be made to link individual differences in sleep patterns and adaptation to life in Antarctica.

Adaptation, Psychological↗
PubMed1982

Changes in human heart rate during sleep following daily physical exercise.

Four fit, healthy young men (aged 20) volunteered for the experiment. After a 5 day control period, they marched for 6 consecutive days (from 09:00 h to 17:00 h) for 34 km/day at a speed of 6 km/h, with an energy expenditure of 35% of individual VO2 max. A recovery period of 5 consecutive days began immediately after the exercise period. Sleep records and electrocardiograms were taken every night during the three periods from 22:00 h to 06:00 h. During the exercise period the night time heart rates increased by about 10%, compared to the previous control condition, and returned to normal during the recovery period. The relation between heart rate changes and sleep stages remained identical throughout the three experimental periods. Three subjects showed an increase in heart rate during paradoxical sleep, compared to the preceding slow wave sleep, while one subject experienced the reverse. The tonic increases in heart rate are discussed in relation to changes in body temperature, sleep patterns, blood composition and hormonal status induced by the physical exercise performed.

Adult↗
PubMed1981

Heart blocks during sleep: a case report in a healthy subject.

Cardiac arrhythmia was fortuitously discovered during an experimental sleep recording in a healthy 50-year-old man. a 24 hr electrocardiographic (ECG) monitoring revealed the prevalence of these abnormalities during sleep and their absence during the awake period. Sleep and ECG were recorded during 4 consecutive nights. Numerous (500-1, 100 events/night) heart blocks and sinus pauses occurred 60-80 min after going to bed. They were never observed during awakenings and were exacerbated during paradoxical sleep. The atrioventricular blocks were of the Wenckebach-Luciani type. No other abnormality was found. These conduction abnormalities are discussed as possibly due to phasic increases in vagal firing, which during paradoxical sleep would be superimposed on the tonic increase in heart rate.

Electrocardiography↗
PubMed1980

Human sleep and adrenal individual reactions to exercise.

Six fit men, aged 20, participated in the 16 day experiment. After a 5 day control period, the subjects marched on 6 consecutive days (from 09:00 h to 17:00 h) for 34 km/day at a speed of 6 km/h, with a backpack adjusted to complete a 35% of individual VO2 max energy expenditure. Control conditions were resumed for a 5 day recovery period. Sleep records were taken every night from 22:00 h to 06:00 h. Urinary 17-hydroxycorticosteroids (17-OHCS) were analysed from a 09:00 h to 17:00 h sample and from overnight urines. Two groups of subjects were defined by their responses to exercise. Four subjects exhibited an increase in stage 3 during the last third of the exercise nights (mean: 163.8 +/- 7.3% of control values) without any change in their adrenal response. Two subjects had no change or a slight decrease in stage 3 but showed increased 09:00--17:00 h 17-OHCS urine excretion (mean: 147 +/- 13% of control values). Sleep latencies were decreased in both groups. However, the 2 subjects of the second group exhibited increased restlessness as measured by the levels of wakefulness, stage 1 and EMG activity. In all subjects, paradoxical sleep was not altered, along with an unchanged all-night excretion of 17-OHCS. It is suggested that differences in adrenal responses to exercise may be responsible for differences in sleep quality. This could explain the discrepancies encountered in the literature about sleep variations after physical exercise.

17-Hydroxycorticosteroids↗
PubMed1978

Measurement of skin temperatures of active subjects by wireless telemetry.

A new sensor has been developed for measurement of skin temperatures of active human subjects that consists of a radio transmitter circuit incorporating a skin thermistor in a small epoxy slab or "tab." These tabs are reuseable, being large enough to permit battery replacement if required. They are glued to a subject's skin (thermistor side facing the skin) with a quick-setting adhesive and are easily removed after a 10-h period with an appropriate solvent. Thermal information is easily obtained from the sensor by a hand-held calibrated radio receiver accurate to +/- 0.1 degree C. This technique permits easy and rapid documentation of the thermal stress of active human subjects without interfering with their activity or clothing.

Body Temperature↗
PubMed1977

Variations in evaporation and body temperatures during sleep in man.

The thermal balance in man was investigated during nocturnal sleep in neutral and warm environments (from 32 to 39.5 degrees C, 45%rh). Changes of body temperatures and skin evaporation were continuously monitored throughout the whole night. In neutral conditions (32 and 34 degrees C) body temperature and skin evaporation decreased during the night, following the circadian rhythm deltaT sk = -0.34 degrees C; deltaT re = -0.52 degrees C;deltaE = -12 W-m-2. In warm conditions, body temperatures and evaporation remained steady. Marked fluctuations of body temperatures and evaporation occurred synchronously with the rapid eye movement (REM) periods. Each REM period induced phasic increase of Tsk reaching +2 degrees C in some cases, with a cessation of evaporation. Tre showed upward and downward rhythmical waves synchronously with REM sleep occurrence. The nocturnal variations of thermal balance were characterized by two rhythms: a basal circadian rhythm and superimposed on it a rhythm conditioned by occurrence of REM sleep every 80-90 min. The phasic changes of body temperatures and evaporation only appeared with REM's. The results suggest that the nervous integrative function conditioning the patterns of sleep, conditions also the phasic cyclic changes of thermoregulatory function.

Adult↗