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Biomedical subjects

B Roussel

Publications and source records attributed to B Roussel.

At least 91 records · Page 5Linked to original sources
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↗
PubMed1976

[Circadian rhythms of rat internal temperatures and thermal ambiance (author's transl)].

Chronic recording of cerebellar and subcutaneous temperatures were carried out in rats maintained at different ambient temperatures in a 12 h light-dark cycle (light from 7 to 19 h). Cerebellar and subcutaneous temperatures followed a rhythm with a period of 24 h with acrophase at 1 h and an amplitude of 0.75 degrees C. The amplitude and acrophase were not altered by modification of the ambient temperature (20-25-30-34 or 35 degrees C), but each elevation of ambient temperature produced a rise in the mean internal temperature of the rat. This rise, hardly perceptible at ambient temperatures of 25 and 30 degrees C, reaches 0.5 degrees C between 20 and 25 degrees C and 1 degrees C between 30 and 34 degrees C. This elevation of temperature was maintained for the duration of the 10 days of observation. These results pose at least three questions: the degree of liaison between the rhythms of activity (waking) and temperature; the lability of the mean internal temperature, which alter with ambient temperature while the amplitude of the circadian rhythm is unaltered and the absence of reduction of mean interanl temperature several days exposure to a raised ambient temperature, even when activity and metabolism are reduced by the second day of exposure.

Animals↗
PubMed1976

[Effects of lesions in the pontine tegmentum on the sleep stages in the rat].

1. Limited coagulations of the locus coeruleus and subcoeruleus nuclei have been performed in rats and the sleep-waking cycle was continuously monitored during 9 days. The cortical and diencephalic noradrenaline content was mesured at the termination of the experiment, on the 10th post lesion day. 2. The bilateral destruction of the locus coeruleus is followed by the appearance of a uro-genital syndrome consisting of hema turia, bladder distension and penile erection. The states of sleep are disturbed during the first two days (increase of slow-wave sleep and decrease of paradoxical sleep times) and thereafter return to normal. Additionally, an hyperthermia appears during the third experimental day. The cortical and diencephalic noradrenaline content decrease to 70%. 3. The simultaneous lesion of both locus coeruleus and subcoeruleus nuclei is followed by the appearance of an aphagia adipsia syndrome in addition to the uro-genital syndrome. After these lesions, it is no long possible to find paradoxical sleep episodes in polygraphic recordings while the amount of slow wave sleep is normal. Cortical and diencephalic noradrenaline content decrease more than 50%. 4. In normal rats direct injection of 6 hydroxydopamine directly in both locus coeruleus and nuclei subcoeruleus had no discernable effects either on the behaviour or on the states of sleep. The cortical noradrenaline content decreased 30% below control values. 5. These results are consistent with but do not prove the hypothesis that part of the pontine tegmentum might play an important role in triggering paradoxical sleep episodes. The role of these regions in the regulation of internal temperature, food consumption and bladder motricity is also discussed.

Animals↗
PubMedDate not supplied

[Intracranial hemorrhages associated with oral anticoagulant therapy. Analysis of 38 cases].

The major risk of oral anticoagulant therapy is haemorrhage potentially affecting all organs. Bleeding in the central nervous system is a rare but severe complication of anticoagulant therapy. This study aimed to analyse a series of intracranial haemorrhages. This series from the Regional Pharmacovigilance Center of Amiens included spontaneously reported and retrospectively collected cases from January 1999 to December 2000. During this period, 38 cases of intracranial bleeding possibly related to oral anticoagulant administration were reported; 19 women and 19 men, median age 69.5 (29 to 87) years. In 34% of the cases, patients died and in 18% neurologic sequelae were still present at the time of the evaluation. In 21 cases (62%), the INR (International Normalized Ratio) was higher than the therapeutic range recommended for the indication. Among the most frequent risk factors, hypertension and recent minor trauma are highlighted in this series. In 17 cases, oral anticoagulants were associated with potentially potentiating drugs. Mental status changes or headache were prominent early symptoms which had often been present for days. Our data confirm that anticoagulant-associated intracranial haemorrhages are not rare, can be severe, potentially fatal and are probably underestimated by physicians. The fact that more than 50% of patients in this series were overanticoagulated at the time of bleeding suggests that many cases of intracranial haemorrhage could be prevented by improved anticoagulation control. Epidemiological studies are needed in order to prospectively evaluate the incidence of this type of complication and its avoidance. The value of anticoagulation clinics can be discussed.

Adult↗