Journées Scientifiques URSI-France JS'12 "Champs électromagnétiques : de la dosimétrie à la santé humaine", Apr 3, 2012
Les résultats de l'étude effectuée sur 21 jeunes adultes volontaires ont révélé des effets atherm... more Les résultats de l'étude effectuée sur 21 jeunes adultes volontaires ont révélé des effets athermiques de l'exposition réelle aux ondes RF de téléphone mobile sur le micro débit sanguin cutané en comparaison avec une exposition sham, par approche laser Doppler thermostatique (LD). L'analyse spectrale du signal LD en fin d'exposition a permis de montrer que ces modifications de vasomotricité cutanée étaient associées à une activité nerveuse sympathique locale plus élevée sous exposition réelle que sous exposition sham. Un test de provocation thermique spécifique induisant une hyperémie réactive maximale effectué à la 25 è minute post-exposition a montré que la réserve vasodilatatrice des microvaisseaux cutanés exposés aux ondes RF était plus grande que celle sous exposition sham.
A cc ep te d A rt ic le This article has been accepted for publication and undergone full peer re... more A cc ep te d A rt ic le This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi:
Objectives : we have previously shown that radiofrequency electromagnetic fields (RF-EMF) (type b... more Objectives : we have previously shown that radiofrequency electromagnetic fields (RF-EMF) (type base station antenna) affect sleep of growing rats when this exposure was associated with a thermal stress. We hypothesize that within the thermoneutral zone, the exposed animals were in a process of saving body's energy. Methods : 13 Wistar rats (3 weeks-old) continuously exposed to RF-EMR during six weeks were compared to 11 non-exposed control rats. After surgery, sleep-wakefulness cycle, cortical and peripheral (caudal, Ttail) skin temperatures and food intake were simultaneously measured within 00-06 pm at environmental temperature (24+-1°C) and at the upper limit of thermoneutral zone (31+-1 °C), combined or not with RF exposure. Prazocine was used as adrenergic inhibitor of post-ganglionic fibres of cutaneous microvessels. Patterns of vigilance states were scored by considering their total duration, mean durations and frequencies of episodes. All parameters were tested with ANO...
In this study, variations in skin micro blood flow and temperature were simultaneously recorded i... more In this study, variations in skin micro blood flow and temperature were simultaneously recorded in 20 adults with a thermostatic laser Doppler system during "radiofrequency" and 'sham' mobil phone's exposure for 20 minutes. These findings show the existence of a vasodilatory effect on skin perfusion of MP radiofrequency emission, which was nonthermal.
OBJECTIVE: to establish whether skin micro blood flow can be modified by exposure to the radiofre... more OBJECTIVE: to establish whether skin micro blood flow can be modified by exposure to the radiofrequency waves emitted by a mobile phone when the latter is held against the jaw and ear. METHODS: Variations in skin micro blood flow and skin temperature in adult volunteers were simultaneously recorded with a thermostatic laser Doppler system during a 20-minute "radiofrequency" exposure session and a 20-minute "sham" session. The skin microvessels' vasodilatory reserve was assessed with a heat challenge at the end of the protocol. RESULTS: During the radiofrequency exposure session, skin micro blood flow increased (vs. baseline) more than during the sham exposure session. The sessions did not differ significant in terms of the skin Accepted Article This article is protected by copyright. All rights reserved. temperature time-course response. The skin microvessels' vasodilatory ability was found to be greater during radiofrequency exposure than during sham exposure. CONCLUSIONS: Our results reveal the existence of a specific vasodilatory effect of mobile phone radiofrequency emission on skin perfusion.
The forced oscillation technique is noninvasive, does not require active co-operation and may thu... more The forced oscillation technique is noninvasive, does not require active co-operation and may thus be useful for studying lung function in young children. Respiratory impedance (Zrs) is measured from oscillating pressure and flow applied by an external generator to the respiratory system, usually at the mouth, and is expressed as respiratory resistance (Rrs) and reactance (Xrs). The frequency content of the child's tidal flow makes it difficult to obtain reliable data below 6-10 Hz. The extra thoracic airway wall motion shunts some of the flow. The resulting artefact may be particularly prominent in preschool children, but may be significantly lessened by varying pressure around the head. Measuring infants is more challenging: the large Zrs value requires equipment with particularly well-studied dynamic characteristics; the subject must be sedated and breathe through the nose, so that the large series impedance of upper airways makes it difficult to correct for the extra thoraci...
Intravenous injection of dopamine (DA) has consistently been shown to depress minute ventilation ... more Intravenous injection of dopamine (DA) has consistently been shown to depress minute ventilation (VE). Whereas at low dosage (</=10 microgram/kg) this effect may be accounted for by inhibition of the carotid sinus nerve chemosensory discharge (CSNCD), other mechanisms appear to be involved with large dosage (>/=50 microgram/kg). The purpose of this study was to elucidate the mechanisms of DA-induced VE depression. The effects of intravenous injection of DA doses ranging from 1 to 200 microgram/kg were studied in 18 anesthetized cats. DA was injected during air and O2 breathing, after alpha-adrenergic blockade by phenoxybenzamine and after baro- and chemodenervation. VE and CSNCD were also simultaneously recorded on four occasions. In contrast to that with use of low-dose DA, VE depression induced by high-dose DA was dissociated from CSNCD, persisted during 100% O2 breathing, and was significantly correlated with the rise in arterial blood pressure. Although blunted, VE depress...
L'objectif est d'étudier les modifications produites chez l'homme par l'émission ... more L'objectif est d'étudier les modifications produites chez l'homme par l'émission d'ondes radiofréquences (RF) d'un téléphone mobile sur le tonus vasculaire sous ambiance thermique constante. Matériels et méthodes. 21 jeunes adultes volontaires ont été étudiés. Les mesures de débit sanguin cutané sont couplées à celles de température cutanée dans la même zone d'exploration par approche laser doppler (LD) thermostatique (Periflux système Perimed, France) de façon non invasive, en continu et en temps réel. Les mesures sont exprimées en unités arbitraires (Unité de Perfusion). Protocole. Deux sondes LD sont appliquées en amont du lobe de l'oreille en contra latéral (= côté contrôle) et ipsi latéral (= côté exposé aux ondes RF). Deux téléphones portables sont utilisés pour l'exposition RF (GSM, bande de 900 MHz, DAS maximal moyenné sur 10g de 0,49 W/kg), l'un pour les expositions RF réelles, l'autre pour les expositions fictives (sham) n'ém...
The liver, like brown adipose tissue, is an important source of nonshivering thermogenesis. We te... more The liver, like brown adipose tissue, is an important source of nonshivering thermogenesis. We tested the hypothesis that the thermal state of the liver is preserved during slow wave sleep but deteriorates during paradoxical sleep. Twelve adult male Wistar rats were equipped with electrodes and thermistor probes--which measured cortical (Tco), interscapular brown adipose tissue (Tibat), and liver (Tl) temperatures--for thermal and sleep studies. Six rats were exposed to thermoneutral (24 degrees C) and 6 to low (9 degrees C) ambient temperature. Isolated paradoxical sleep episodes preceded and followed by more than 3 minutes of wakefulness or slow wave sleep were analyzed. The Tco, Tibat, and Tl levels were also assessed during the slow wave sleep that preceded each isolated paradoxical sleep episode. During slow wave sleep, the Tibat and Tl were clearly higher in rats exposed to the cold than in those exposed to the thermoneutral condition (< 1 degrees C). During paradoxical sle...
Some practical aspects of respiratory function testing (RFT) are reviewed with special interest o... more Some practical aspects of respiratory function testing (RFT) are reviewed with special interest on applications in preschool children. RFT may be used for diagnostic, management and follow up purposes. Children may benefit from RFT in a variety of pathological situations. Asthma and other obstructive airways diseases certainly represent the most frequent conditions. Vital Capacity and Forced Expiratory Volume in one second (FEV1) may usually be obtained from age 7 on. In smaller children, the forced expiratory manoeuvre is much less successful. Non invasive measurements such as respiratory resistance (Rrs) or specific airway resistance (sRaw) may be used. Rrs is usually measured by the interrupter technique or the forced oscillation technique and sRaw by body plethysmography, not requiring the estimation of thoracic gas volume. Because much variability is introduced by the upper airways, these parameters are less suited than FEV1 to establish the degree of baseline airway obstructio...
ABSTRACT Avian sleep quality depends on its depth (deeper sleep being of better quality). In king... more ABSTRACT Avian sleep quality depends on its depth (deeper sleep being of better quality). In king penguins (Aptenodytes patagonica), sleep may be disturbed by congeners passing in the sleeper&#39;s vicinity. As king penguin activity is increased in the morning, sleep disturbances are more likely to occur during this time period. One might therefore assume that afternoon sleepers (AS) sleep more profoundly than morning sleepers (MS). To test this hypothesis, we examined the diurnal variations in sleep depth of king penguins sleeping in resting sites adjacent to the colony of &#39;&#39;La Baie du Marin&#39;&#39; (Crozet Archipelago). We measured the bodily tactile arousal threshold at the upper back level. The arousal threshold in AS was twice as high as in MS. This study demonstrates for the first time that sleep depth changes according to time of day in a diurnal wild bird. We postulate that diurnal sleep depth is increased due to decreased congener movements close to the sleeping penguin.
Journées Scientifiques URSI-France JS'12 "Champs électromagnétiques : de la dosimétrie à la santé humaine", Apr 3, 2012
Les résultats de l'étude effectuée sur 21 jeunes adultes volontaires ont révélé des effets atherm... more Les résultats de l'étude effectuée sur 21 jeunes adultes volontaires ont révélé des effets athermiques de l'exposition réelle aux ondes RF de téléphone mobile sur le micro débit sanguin cutané en comparaison avec une exposition sham, par approche laser Doppler thermostatique (LD). L'analyse spectrale du signal LD en fin d'exposition a permis de montrer que ces modifications de vasomotricité cutanée étaient associées à une activité nerveuse sympathique locale plus élevée sous exposition réelle que sous exposition sham. Un test de provocation thermique spécifique induisant une hyperémie réactive maximale effectué à la 25 è minute post-exposition a montré que la réserve vasodilatatrice des microvaisseaux cutanés exposés aux ondes RF était plus grande que celle sous exposition sham.
A cc ep te d A rt ic le This article has been accepted for publication and undergone full peer re... more A cc ep te d A rt ic le This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi:
Objectives : we have previously shown that radiofrequency electromagnetic fields (RF-EMF) (type b... more Objectives : we have previously shown that radiofrequency electromagnetic fields (RF-EMF) (type base station antenna) affect sleep of growing rats when this exposure was associated with a thermal stress. We hypothesize that within the thermoneutral zone, the exposed animals were in a process of saving body's energy. Methods : 13 Wistar rats (3 weeks-old) continuously exposed to RF-EMR during six weeks were compared to 11 non-exposed control rats. After surgery, sleep-wakefulness cycle, cortical and peripheral (caudal, Ttail) skin temperatures and food intake were simultaneously measured within 00-06 pm at environmental temperature (24+-1°C) and at the upper limit of thermoneutral zone (31+-1 °C), combined or not with RF exposure. Prazocine was used as adrenergic inhibitor of post-ganglionic fibres of cutaneous microvessels. Patterns of vigilance states were scored by considering their total duration, mean durations and frequencies of episodes. All parameters were tested with ANO...
In this study, variations in skin micro blood flow and temperature were simultaneously recorded i... more In this study, variations in skin micro blood flow and temperature were simultaneously recorded in 20 adults with a thermostatic laser Doppler system during "radiofrequency" and 'sham' mobil phone's exposure for 20 minutes. These findings show the existence of a vasodilatory effect on skin perfusion of MP radiofrequency emission, which was nonthermal.
OBJECTIVE: to establish whether skin micro blood flow can be modified by exposure to the radiofre... more OBJECTIVE: to establish whether skin micro blood flow can be modified by exposure to the radiofrequency waves emitted by a mobile phone when the latter is held against the jaw and ear. METHODS: Variations in skin micro blood flow and skin temperature in adult volunteers were simultaneously recorded with a thermostatic laser Doppler system during a 20-minute "radiofrequency" exposure session and a 20-minute "sham" session. The skin microvessels' vasodilatory reserve was assessed with a heat challenge at the end of the protocol. RESULTS: During the radiofrequency exposure session, skin micro blood flow increased (vs. baseline) more than during the sham exposure session. The sessions did not differ significant in terms of the skin Accepted Article This article is protected by copyright. All rights reserved. temperature time-course response. The skin microvessels' vasodilatory ability was found to be greater during radiofrequency exposure than during sham exposure. CONCLUSIONS: Our results reveal the existence of a specific vasodilatory effect of mobile phone radiofrequency emission on skin perfusion.
The forced oscillation technique is noninvasive, does not require active co-operation and may thu... more The forced oscillation technique is noninvasive, does not require active co-operation and may thus be useful for studying lung function in young children. Respiratory impedance (Zrs) is measured from oscillating pressure and flow applied by an external generator to the respiratory system, usually at the mouth, and is expressed as respiratory resistance (Rrs) and reactance (Xrs). The frequency content of the child's tidal flow makes it difficult to obtain reliable data below 6-10 Hz. The extra thoracic airway wall motion shunts some of the flow. The resulting artefact may be particularly prominent in preschool children, but may be significantly lessened by varying pressure around the head. Measuring infants is more challenging: the large Zrs value requires equipment with particularly well-studied dynamic characteristics; the subject must be sedated and breathe through the nose, so that the large series impedance of upper airways makes it difficult to correct for the extra thoraci...
Intravenous injection of dopamine (DA) has consistently been shown to depress minute ventilation ... more Intravenous injection of dopamine (DA) has consistently been shown to depress minute ventilation (VE). Whereas at low dosage (</=10 microgram/kg) this effect may be accounted for by inhibition of the carotid sinus nerve chemosensory discharge (CSNCD), other mechanisms appear to be involved with large dosage (>/=50 microgram/kg). The purpose of this study was to elucidate the mechanisms of DA-induced VE depression. The effects of intravenous injection of DA doses ranging from 1 to 200 microgram/kg were studied in 18 anesthetized cats. DA was injected during air and O2 breathing, after alpha-adrenergic blockade by phenoxybenzamine and after baro- and chemodenervation. VE and CSNCD were also simultaneously recorded on four occasions. In contrast to that with use of low-dose DA, VE depression induced by high-dose DA was dissociated from CSNCD, persisted during 100% O2 breathing, and was significantly correlated with the rise in arterial blood pressure. Although blunted, VE depress...
L'objectif est d'étudier les modifications produites chez l'homme par l'émission ... more L'objectif est d'étudier les modifications produites chez l'homme par l'émission d'ondes radiofréquences (RF) d'un téléphone mobile sur le tonus vasculaire sous ambiance thermique constante. Matériels et méthodes. 21 jeunes adultes volontaires ont été étudiés. Les mesures de débit sanguin cutané sont couplées à celles de température cutanée dans la même zone d'exploration par approche laser doppler (LD) thermostatique (Periflux système Perimed, France) de façon non invasive, en continu et en temps réel. Les mesures sont exprimées en unités arbitraires (Unité de Perfusion). Protocole. Deux sondes LD sont appliquées en amont du lobe de l'oreille en contra latéral (= côté contrôle) et ipsi latéral (= côté exposé aux ondes RF). Deux téléphones portables sont utilisés pour l'exposition RF (GSM, bande de 900 MHz, DAS maximal moyenné sur 10g de 0,49 W/kg), l'un pour les expositions RF réelles, l'autre pour les expositions fictives (sham) n'ém...
The liver, like brown adipose tissue, is an important source of nonshivering thermogenesis. We te... more The liver, like brown adipose tissue, is an important source of nonshivering thermogenesis. We tested the hypothesis that the thermal state of the liver is preserved during slow wave sleep but deteriorates during paradoxical sleep. Twelve adult male Wistar rats were equipped with electrodes and thermistor probes--which measured cortical (Tco), interscapular brown adipose tissue (Tibat), and liver (Tl) temperatures--for thermal and sleep studies. Six rats were exposed to thermoneutral (24 degrees C) and 6 to low (9 degrees C) ambient temperature. Isolated paradoxical sleep episodes preceded and followed by more than 3 minutes of wakefulness or slow wave sleep were analyzed. The Tco, Tibat, and Tl levels were also assessed during the slow wave sleep that preceded each isolated paradoxical sleep episode. During slow wave sleep, the Tibat and Tl were clearly higher in rats exposed to the cold than in those exposed to the thermoneutral condition (< 1 degrees C). During paradoxical sle...
Some practical aspects of respiratory function testing (RFT) are reviewed with special interest o... more Some practical aspects of respiratory function testing (RFT) are reviewed with special interest on applications in preschool children. RFT may be used for diagnostic, management and follow up purposes. Children may benefit from RFT in a variety of pathological situations. Asthma and other obstructive airways diseases certainly represent the most frequent conditions. Vital Capacity and Forced Expiratory Volume in one second (FEV1) may usually be obtained from age 7 on. In smaller children, the forced expiratory manoeuvre is much less successful. Non invasive measurements such as respiratory resistance (Rrs) or specific airway resistance (sRaw) may be used. Rrs is usually measured by the interrupter technique or the forced oscillation technique and sRaw by body plethysmography, not requiring the estimation of thoracic gas volume. Because much variability is introduced by the upper airways, these parameters are less suited than FEV1 to establish the degree of baseline airway obstructio...
ABSTRACT Avian sleep quality depends on its depth (deeper sleep being of better quality). In king... more ABSTRACT Avian sleep quality depends on its depth (deeper sleep being of better quality). In king penguins (Aptenodytes patagonica), sleep may be disturbed by congeners passing in the sleeper&#39;s vicinity. As king penguin activity is increased in the morning, sleep disturbances are more likely to occur during this time period. One might therefore assume that afternoon sleepers (AS) sleep more profoundly than morning sleepers (MS). To test this hypothesis, we examined the diurnal variations in sleep depth of king penguins sleeping in resting sites adjacent to the colony of &#39;&#39;La Baie du Marin&#39;&#39; (Crozet Archipelago). We measured the bodily tactile arousal threshold at the upper back level. The arousal threshold in AS was twice as high as in MS. This study demonstrates for the first time that sleep depth changes according to time of day in a diurnal wild bird. We postulate that diurnal sleep depth is increased due to decreased congener movements close to the sleeping penguin.
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