Hypoalgesia and parasympathetic effects of millimeter waves on experimentally induced pain in healthy volunteers.

In humans, exposure to electromagnetic millimeter waves (MMW) has a hypoalgesic effect. In animals, this effect has been shown to depend on innervation density of the area exposed. This study aims to assess hypoalgesic and parasympathetic effects of MMW applied on the palmar side of the wrist in healthy participants. In a within-subject design, 10 healthy participants had the palmar side of their wrist exposed to MMW (61.25 GHz, 17 mW/cm2) for 30 minutes, 1 h, & 1 h30, and 30 minutes of sham exposure. Experimental pain was induced after the exposure sessions with the Cold Pressor Test, and pain threshold and pain tolerance values were compared to that of the sham condition. Participants' heart rate and blood pressure were measured before and after exposures. Finally, innocuity of the exposure system was controlled with a pre-post exposure visual examination scale and skin temperature measured by a thermal camera. Exposure to 30 minutes, but not 1 h or 1 h30, of MMW led to significant increases in pain thresholds compared to the sham condition, but no increase of pain tolerance. All conditions led to decreased heart rate, while no change in blood pressure was observed. No change in skin state or temperature was observed for any of the conditions. MMW applied on the inner part of the wrist diminish pain sensations more effectively than placebo, and seem to increase parasympathetic activities, while remaining innocuous. Building a miniaturized MMW emission system to be worn on the wrist would provide access to ambulatory MMW therapy for pain management.

A drug free solution for improving the quality of life of fibromyalgia patients (Fibrepik): study protocol of a multicenter, randomized, controlled effectiveness trial.

BACKGROUND: Fibromyalgia is a form of chronic widespread pain that is defined as a syndrome of chronic symptoms of moderate to severe intensity, including diffuse pain, fatigue, sleep disturbance, cognitive impairment, and numerous somatic complaints. To date, there is no specific drug treatment for fibromyalgia but only symptomatic treatments. A drug free solution based on a wristband that emits millimeter waves associated with a therapeutic coaching program was developed. The application of millimeter waves on an innervated area has been described to have a neuromodulating effect, due to endorphin release stimulation and parasympathetic activation. Coaching is carried out to improve the patient's adherence and to increase compliance and effectiveness of the treatment. Regular use of this solution by fibromyalgia patients is expected to improve sleep quality, reduce anxiety and pain levels, and, at the end, increase the quality of life. METHODS: This trial is performed over 8 French inclusion centers for a total of 170 patients. The effectiveness of the solution is evaluated according to the primary objective, the improvement of the quality of life measured through the dedicated Fibromyalgia Impact Questionnaire after 3 months. Patients are randomized in two groups, Immediate or Delayed. The Immediate group has access to the solution just after randomization in addition to standard care, while Delayed has access to the standard of care and waits for 3 months to have the solution. The purpose of this methodology is to limit deception bias and facilitate inclusion. The solution consists in using the device for three sessions of 30 min per day and four coaching sessions spread over the first 2 months of wristband usage. DISCUSSION: The objective is to confirm the effect of the integrative approach based on endorphin stimulation and a therapeutic coaching program in nociplastic pain and specifically for the patient suffering from fibromyalgia. If the effectiveness of the solution is demonstrated, we will be able to respond to the demand of fibromyalgia patients for access to an effective non-medicinal treatment to improve their quality of life. TRIAL REGISTRATION: ClinicalTrials.gov NCT05058092.

Evaluation of the Effect of Chronic 94 GHz Exposure on Gene Expression in the Skin of Hairless Rats In Vivo.

Millimeter waves (MMW) are broadband frequencies that have recently been used in several applications in wireless communications, medical devices and nonlethal weapons [i.e., the nonlethal weapon, Active Denial Systems, (ADS) operating at 94-95 GHz, CW]. However, little information is available on their potential effects on humans. These radio-frequencies are absorbed and stopped by the first layer of the skin. In this study, we evaluated the effects of 94 GHz on the gene expression of skin cells. Two rat populations consisting of 17 young animals and 14 adults were subjected to chronic long-term 94 GHz MMW exposure. Each group of animals was divided into exposed and sham subgroups. The two independent exposure experiments were conducted for 5 months with rats exposed 3 h per day for 3 days per week to an incident power density of 10 mW/cm2, which corresponded to twice the ICNIRP limit of occupational exposure for humans. At the end of the experiment, skin explants were collected and RNA was extracted. Then, the modifications to the whole gene expression profile were analyzed with a gene expression microarray. Without modification of the animal's temperature, long-term chronic 94 GHz-MMW exposure did not significantly modify the gene expression of the skin on either the young or adult rats.

Alumina nanoparticles size and crystalline phase impact on cytotoxic effect on alveolar epithelial cells after simple or HCl combined exposures.

Applications using alumina nanoparticles (Al2O3 NPs) have incredibly increased in different fields of activity. In defense and aerospace fields, solid composite propellants use leads to complex combustion aerosols emissions containing high concentrations of Al2O3 NPs and hydrogen chloride gas (HCl). To better characterize potential hazard resulting from exposure to these aerosols, this study assesses cytotoxic effects of mixtures containing both compounds on human pulmonary alveolar epithelial cells (A549 cell line) after 24 h exposures. After all co-exposures cell viability was >80%. However co-exposures decrease normalized real-time cell index. Significant decreases of intracellular reduced glutathione pool were also observed after co-exposures to γ-10 nm or γ/δ-13 nm Al2O3 NPs and HCl. Co-incubations with γ/δ-13 nm or γ-500 nm Al2O3 particles and HCl induced significant DNA double-strand breaks increases. Moreover all co-exposures and HCl alone disrupted cell cycle (increased G1 phase cells). Transmission Electron Microscopy (TEM) observations revealed γ/δ-13 nm Al2O3NPs adsorption and internalization in cell cytoplasm only, suggesting indirect genotoxic effects. According to our results Al2O3 particles/HCl mixtures can induce cytotoxic effects and Al2O3 size and crystallinity are two main parameters influencing cytotoxic mechanisms.

Long-term follow-up of muscle lipid accumulation, mitochondrial activity and oxidative stress and their relationship with impaired glucose homeostasis in high fat high fructose diet-fed rats.

Metabolic syndrome components, including obesity, dyslipidemia and impaired glucose homeostasis, become a major public health issue. Muscles play a predominant role in insulin-mediated glucose uptake, and high fat diets may negatively affect muscle function and homeostasis. This work aimed to study the time-course of muscle lipid accumulation, oxidative stress and mitochondrial dysfunction and their association to impaired glucose homeostasis in rats fed an obesogenic diet. Male Wistar rats were fed with a standard or a high fat/high fructose (HFHFr) diet and sacrificed on 4, 8, 12, 16, 20 weeks. Rats fed the HFHFr diet developed mild overweight, increased liver and adipose tissue weights and glucose intolerance. The impaired glucose homeostasis increased gradually with the HFHFr diet to become significant on the 12th and 16th weeks of diet. In parallel, the muscle lipid composition showed an increase in the saturated fatty acids and the monounsaturated fatty acids with a marked decrease in the polyunsaturated fatty acids. The HFHFr diet also increased muscle contents of both diacylglycerols and Ceramides. Surprisingly, HFHFr diet did not induce major muscle mitochondrial dysfunction or oxidative stress. These results indicate that muscle lipid alterations, as well as impaired glucose homeostasis occur as early as the 8th week of HFHFr diet, increase to reach a plateau around the 12th-16th weeks of diet, and then attenuate towards the end of study. At these diet treatment durations, muscle mitochondrial activity and oxidative stress remained unchanged and do not seem to have a major role in the observed impaired glucose homeostasis.

Changes in Red Blood Cell membrane lipid composition: A new perspective into the pathogenesis of PKAN.

Pantothenate Kinase-Associated Neurodegeneration (PKAN) is a form of Neurodegeneration with Brain Iron Accumulation (NBIA) associated with mutations in the pantothenate kinase 2 gene (PANK2). The PANK2 catalyzes the first step of coenzyme A (CoA) biosynthesis, a pathway producing an essential cofactor that plays a key role in energy and lipid metabolism. The majority of PANK2 mutations reduces or abolishes the activity of the enzyme. In around 10% of cases with PKAN, the presence of deformed red blood cells with thorny protrusions in the circulation has been detected. Changes in membrane protein expression and assembly during erythropoiesis were previously explored in patients with PKAN. However, data on red blood cell membrane phospholipid organization are still missing in this disease. In this study, we performed lipidomic analysis on red blood cells from Italian patients affected by PKAN with a particular interest in membrane physico-chemical properties. We showed an increased number of small red blood cells together with membrane phospholipid alteration, particularly a significant increase in sphingomyelin (SM)/phosphatidylcholine (PC) and SM/phosphatidylethanolamine (PE) ratios, in subjects with PKAN. The membrane structural abnormalities were associated with membrane fluidity perturbation. These morphological and functional characteristics of red blood cells in patients with PKAN offer new possible tools in order to shed light on the pathogenesis of the disease and to possibly identify further biomarkers for clinical studies.

Biological effects of double-walled carbon nanotubes on the innate immune system: An in vitro study on THP-1 human monocytes.

DWCNTs have numerous industrial and biomedical applications and several studies reported that they could act as immunomodulator systems. The immune system is the first line of defence of the human body when exposed to particulate matter. In order to investigate DWCNTs' role on innate immunity, we used THP-1 monocytic cells for the purpose of this study. We showed that DWCNTs were not cytotoxic until 6h, 24h, 48h and 72h of incubation with THP-1 monocytic cells (concentrations tested from 10 to 50µg/mL). From 6h to 72h of incubation of THP-1 cells with DWCNTs, we measured a significant increase of the baseline cell index using xCELLigence(®) technology showing cell adhesion. After 24h of exposure, DWCNTs agglomerates were localized in THP-1 monocyte cytoplasm and cell adhesion was observed simultaneously with a significant increase in the expression of CD11b and CD14 cell surface proteins. Pro-inflammatory cytokine secretion (IL-1ß, IL-6, IL-8, TNF-α and IL-10) was also measured in supernatants after 6h or 24h of exposure to DWCNTs. This pro-inflammatory response was increased in THP-1 monocytic cells pre-treated with LPS. Altogether, our data indicate that DWCNTs induce an increased pro-inflammatory response of THP-1 monocytes and seem to modulate cell surface protein expression confirming that DWCNTs could act as stimulators of innate immunity.

Liver mitochondrial function in ZDF rats during the early stages of diabetes disease.

The aim of this study was to characterize the early alterations of the liver mitochondrial function in ZDF (fa/fa) rats that develop diabetes compared to that of their lean counterparts ZDF (fa/+). Liver mitochondrial function was examined in 11- and 14-week-old ZDF (fa/fa) and ZDF lean (fa/+) rats. Oxygen consumption, H2O2 release, calcium retention capacity (CRC), membrane potential, membrane fluidity, and fatty acid composition were analyzed. State 3 oxygen consumption with palmitoyl-carnitine increases between 11 and 14 weeks of age in lean but not in diabetic animals. This response was not seen with other substrates, suggesting that the use of fatty acids is impaired in diabetic rats. H2O2 release was lower in 14-week-old ZDF (fa/fa) rats as compared to ZDF lean (fa/+). These changes were not associated with differences in enzymatic activities of the respiratory complexes, suggesting regulatory mechanisms independent of their expression levels. Membrane fluidity and composition analyses show only slight effects linked to diabetes progression. The most salient feature was a reduction in CRC in the presence of CsA, an effect reflecting PTP dysregulation. Our data suggest few changes of mitochondrial function in ZDF fa/fa rats. At the age of 11 weeks, liver mitochondria have mainly a reduced effect of CsA on CRC.

First epidemiological study on occupational radar exposure in the French Navy: a 26-year cohort study.

This retrospective cohort study deals with the causes of death among 57,000 military personnel who served in the French Navy surface vessels and were observed over the period 1975-2000. We successively compared the mortality rate and the specific causes of death between two groups differing in their potential exposure levels to radar. Occupational exposure was defined according to the on-board workplace (radar and control groups). The age-adjusted death ratios of the navy personnel were compared. For all causes of death, the results showed that 885 deaths in the radar group and 299 in the control group occurred (RR = 1.00 (95% CI: 0.88-1.14)). RRs were 0.92 (95% CI: 0.69-1.24) for neoplasms. For the duration of follow-up, the results did not show an increased health risk for military personnel exposed to higher levels of radio frequencies in the radar group, but the number of deaths was very small for some cancer sites.

The mitochondrial-targeted antioxidant MitoQ ameliorates metabolic syndrome features in obesogenic diet-fed rats better than Apocynin or Allopurinol.

The prevalence of metabolic syndrome (MetS) components including obesity, dyslipidemia, insulin resistance (IR), and hepatic steatosis is rapidly increasing in wealthy societies. It is accepted that inflammation/oxidative stress are involved in the initiation/evolution of the MetS features. The present work was designed to evaluate the effects of three major cellular ROS production systems on obesity, glucose tolerance, and hepatic steatosis development and on oxidative stress onset. To do so, 40 young male Sprague-Dawley rats were divided into 5 groups: 1-control group, 2-high fat (HF) group (60% energy from fat), 3-HF+ MitoQ (mitochondrial ROS scavenger), 4-HF+ Apocynin (NADPH oxidase inhibitor), 5-HF+ Allopurinol (xanthine oxidase inhibitor). After 8 weeks of these treatments, surrogate MetS, mitochondrial function, and oxidative stress markers were measured in blood and liver. As expected, rats that were fed the HF diet exhibited increased body weight, glucose intolerance, overt hepatic steatosis, and increased hepatic oxidative stress. The impacts of the studied ROS inhibitors on these aspects of the MetS were markedly different. MitoQ showed the most clinically relevant effects, attenuating body weight gain and glucose intolerance provoked by the HF diet. Both Apocynin and Allopurinol showed limited effects suggesting secondary roles of xanthine oxidase (XO) or NADPH oxidase-dependent ROS production in the onset of oxidative stress-dependent obesity, glucose intolerance, and hepatic steatosis process. Thus, MitoQ revealed the central role of mitochondrial oxidative stress in the development of MetS and suggested that mitochondria-targeted antioxidants may be worth considering as potentially helpful therapies for MetS features.

Interaction Study of an Amorphous Solid Dispersion of Cyclosporin A in Poly-Alpha-Cyclodextrin with Model Membranes by (1)H-, (2)H-, (31)P-NMR and Electron Spin Resonance.

The properties of an amorphous solid dispersion of cyclosporine A (ASD) prepared with the copolymer alpha cyclodextrin (POLYA) and cyclosporine A (CYSP) were investigated by (1)H-NMR in solution and its membrane interactions were studied by (1)H-NMR in small unilamellar vesicles and by (31)P (2)H NMR in phospholipidic dispersions of DMPC (dimyristoylphosphatidylcholine) in comparison with those of POLYA and CYSP alone. (1)H-NMR chemical shift variations showed that CYSP really interacts with POLYA, with possible adduct formation, dispersion in the solid matrix of the POLYA, and also complex formation. A coarse approach to the latter mechanism was tested using the continuous variations method, indicating an apparent 1 : 1 stoichiometry. Calculations gave an apparent association constant of log Ka = 4.5. A study of the interactions with phospholipidic dispersions of DMPC showed that only limited interactions occurred at the polar head group level ((31)P). Conversely, by comparison with the expected chain rigidification induced by CYSP, POLYA induced an increase in the fluidity of the layer while ASD formation led to these effects almost being overcome at 298 K. At higher temperature, while the effect of CYSP seems to vanish, a resulting global increase in chain fluidity was found in the presence of ASD.

Chronic Electromagnetic Exposure at Occupational Safety Level Does Not Affect the Metabolic Profile nor Cornea Healing after LASIK Surgery.

LASIK eye surgery has become a very common practice for myopic people, especially those in the military. Sometimes undertaken by people who need to keep a specific medical aptitude, this surgery could be performed in secret from the hierarchy and from the institute medical staff. However, even though the eyes have been previously described as one of the most sensitive organs to electromagnetic fields in the human body, no data exist on the potential deleterious effects of electromagnetic fields on the healing eye. The consequences of chronic long-lasting radar exposures at power density, in accordance with the occupational safety standards (9.71 GHz, 50 W/m(2)), were investigated on cornea healing. The metabolic and clinical statuses after experimental LASIK keratotomy were assessed on the different eye segments in a New Zealand rabbit model. The analysis methods were performed after 5 months of exposure (1 hour/day, 3 times/week). Neither clinical or histological examinations, nor experimental data, such as light scattering, (1)H-NMR HRMAS metabolomics, (13)C-NMR spectra of lipidic extracts, and antioxidant status, evidenced significant modifications. It was concluded that withdrawing the medical aptitude of people working in electromagnetic field environments (i.e., radar operators in the navy) after eye surgery was not justified.

Rat liver mitochondrial membrane characteristics and mitochondrial functions are more profoundly altered by dietary lipid quantity than by dietary lipid quality: effect of different nutritional lipid patterns.

Dietary lipids are known to affect the composition of the biological membrane and functions that are involved in cell death and survival. The mitochondrial respiratory chain enzymes are membrane protein complexes whose function depends on the composition and fluidity of the mitochondrial membrane lipid. The present study aimed at investigating the impact of different nutritional patterns of dietary lipids on liver mitochondrial functions. A total of forty-eight Wistar male rats were divided into six groups and fed for 12 weeks with a basal diet, lard diet or fish oil diet, containing either 50 or 300 g lipid/kg. The 30 % lipid intake increased liver NEFA, TAG and cholesterol levels, increased mitochondrial NEFA and TAG, and decreased phospholipid (PL) levels. SFA, PUFA and unsaturation index (UI) increased, whereas MUFA and trans-fatty acids (FA) decreased in the mitochondrial membrane PL in 30 % fat diet-fed rats compared with 5 % lipid diet-fed rats. PL UI increased with fish oil diet v. basal and lard-rich diets, and PL trans-FA increased with lard diet v. basal and fish oil diets. The 30 % lipid diet intake increased mitochondrial membrane potential, membrane fluidity, mitochondrial respiration and complex V activity, and decreased complex III and IV activities. With regard to lipid quality effects, ß-oxidation decreased with the intake of basal or fish oil diets compared with that of the lard diet. The intake of a fish oil diet decreased complex III and IV activities compared with both the basal and lard diets. In conclusion, the characteristics and mitochondrial functions of the rat liver mitochondrial membrane are more profoundly altered by the quantity of dietary lipid than by its quality, which may have profound impacts on the pathogenesis and development of non-alcoholic fatty liver disease.

Lung surfactant DPPG phospholipid inhibits vaccinia virus infection.

Vaccinia virus (VACV) was used as a surrogate of Variola virus (genus Orthopoxvirus), the causative agent of smallpox, to study orthopoxvirus infection via the respiratory airway. Lung surfactant, a physiological barrier to infection encountered by the virus, is predominantly composed of phospholipids whose role during orthopoxvirus infection has not been investigated. An attenuated Lister strain, derived from the traditional smallpox vaccine and the Western Reserve (WR) strain, lethal for mice infected by the respiratory route, were examined for their ability to bind various surfactant phospholipids. Dipalmitoyl phosphatidylglycerol (DPPG) was found to interact with both VACV strains. DPPG incorporated in small unilamellar vesicle (SUV-DPPG) inhibited VACV cell infection, unlike other phospholipids tested. Both pre-incubation of virus with SUV-DPPG and pretreatment of the cell with SUV-DPPG inhibited cell infection. This specific DPPG effect was shown to be concentration and time dependent and to prevent the first step of the viral cycle, i.e. virus cell attachment. Cryo-electron microscopy highlighted the interaction between the virus and SUV-DPPG. In the presence of the phospholipid, virus particles displayed a hedgehog-like appearance due to the attachment of lipid vesicles. Mice infected intranasally with VACV-WR pre-incubated with SUV-DPPG survived a lethal infection. These data suggest that DPPG in lung surfactant could reduce the amount of orthopoxvirus particles able to infect pneumocytes at the beginning of a respiratory poxvirus infection. The knowledge acquired during this study of virus-DPPG interactions may be used to develop novel chemotherapeutic strategies for smallpox.

ESR and NMR studies provide evidence that phosphatidyl glycerol specifically interacts with poxvirus membranes.

BACKGROUND: The lung would be the first organ targeted in case of the use of Variola virus (the causative agent of smallpox) as a bioweapon. Pulmonary surfactant composed of lipids (90%) and proteins (10%) is considered the major physiological barrier against airborne pathogens. The principle phospholipid components of lung surfactant were examined in an in vitro model to characterize their interactions with VACV, a surrogate for variola virus. One of them, Dipalmitoyl phosphatidylglycerol (DPPG), was recently shown to inhibit VACV cell infection. RESULTS: The interactions of poxvirus particles from the Western Reserve strain (VACV-WR) and the Lister strain (VACV-List) with model membranes for pulmonary surfactant phospholipids, in particular DPPG, were studied by Electron Spin Resonance (ESR) and proton Nuclear Magnetic Resonance (1H-NMR). ESR experiments showed that DPPG exhibits specific interactions with both viruses, while NMR experiments allowed us to deduce its stoichiometry and to propose a model for the mechanism of interaction at the molecular level. CONCLUSIONS: These results confirm the ability of DPPG to strongly bind to VACV and suggest that similar interactions occur with variola virus. Similar studies of the interactions between lipids and other airborne pathogens are warranted.

[What's new in biomedical applications for Terahertz (THz) technology]. / A la frontière onde-lumière : que peuvent apporter les techniques térahertz (THz) dans le domaine de la santé ?

Terahertz technologies have recently been applied to develop high resolution imaging. Since practical portable systems can be designed, the possibilty has emerged to easily screen for biohazards and concealed objects, a procedure which usually requires remote analysis. Applications of THz are also envisaged in the medical field, because this technology offers a degree of accuracy never reached before in molecule analysis. Skin abnormalities and dental health care are two promising targets of THz applications. Nevertheless, potential hazards and health effects of THz exposure should be monitored carefully, particularly since some data suggest induction of genomic instability.

Effects of high and low inspired fractions of oxygen on horse erythrocyte membrane properties, blood viscosity and muscle oxygenation during anaesthesia.

OBJECTIVES: To evaluate whether a period of hyperoxia or after a period of hypoxia produced changes attributable to reactive oxygen species in anaesthetized horses. STUDY DESIGN: Prospective randomized experimental study. ANIMALS: Six healthy (ASA I) geldings, aged 4.5-9.5 years and weighing 510-640 kg(-1). METHODS: After 30 minutes breathing air as carrier gas for isoflurane, horses were assigned randomly to breathe air as carrier gas (CG0.21) or oxygen as carrier gas (CG1.00) for a further 90 minutes. After an interval of 1 month each horse was re-anaesthetized with the other carrier gas for the 90 minute test period. Ventilation was controlled throughout anaesthesia. Arterial blood was sampled to measure gas tensions, lactate, cholesterol, vitamin E, 4-hydroxy-alkenals, 8-epi-PGF(2 alpha), half haemolysis time, half erythrolysis time, and erythrocyte membrane fluidity. Muscle blood flow and oxygenation were evaluated by near infrared spectroscopy and coloured Doppler. RESULTS: After the first 30 minutes horses were hypoxemic. Subsequently the CG1.00 group became hyperoxaemic (PaO(2) approximately 240 mmHg) whereas the CG0.21 group remained hypoxaemic (PaO(2) approximately 60 mmHg) and had increased lactate concentration. No significant changes in vitamin E, 4-hydroxy-alkenals, or 8-epi-PGF(2 alpha) concentrations were detected. During the 90 minute test period the CG0.21 group had increased resistance to free-radical-mediated lysis in erythrocytes, whereas the CG1.00 group had slightly decreased resistance of whole blood to haemolysis. CG0.21 induced a progressive muscle deoxygenation whereas CG1.00 induced an increase in muscle oxygen saturation followed by progressive deoxygenation towards baseline. CONCLUSIONS: and clinical relevance During isoflurane anaesthesia in horses, the hyperoxia induced by changing from air to oxygen induced minimal damage from reactive oxygen species. Using air as the carrier gas decreased skeletal muscle oxygenation compared with using oxygen.

Physicochemical properties and membrane interactions of anti-apoptotic derivatives 2-(4-fluorophenyl)-3-(pyridin-4-yl)imidazo[1,2-a]pyridine depending on the hydroxyalkylamino side chain length and conformation: an NMR and ESR study.

Three imidazo[1,2-a]pyridine derivatives 3a-c have been synthesized from p38 kinase inhibitor structures and evaluated as anti-apoptosis agents. These drugs were designed to interact with nucleic acids and membrane interactions by varying the chain length in position 6, from hydroxyethylamino (3a), to hydroxybutylamino (3b) and hydroxyhexylamino (3c). First experiments showed that 3a and 3b were insoluble in water while 3c could be solubilized in water despite its partition coefficient (logP=3.2). This latter feature was explained by the formation of a fifth intramolecular cycle thus allowing supramolecular structure formation (NMR and MD calculations). The interactions with membranes have been studied using (1)H, (2)H, (31)P Nuclear Magnetic Resonance (NMR), Electron Spin Resonance (ESR) and High Resolution-Magic Angle Spinning (HR-MAS). Despite the insolubility of 3a and 3b in water, these derivatives could be partially solubilized by synthetic phospholipidic model membranes (small unilamellar vesicles, SUV). (1)H NMR paramagnetic broadening experiments performed on the same models showed that 3a was located in the external layer, probably close to the surface while 3b only formed external superficial adducts. Supplementary (31)P, (2)H NMR and ESR experiments on phospholipid dispersions confirmed the location of 3a close to the polar headgroup of the external layer of the membrane, this resulting in a 2K lowering of the transition temperature. Moreover, no significant interaction was detected on the deep part of the layer ((2)H NMR and 16NS ESR experiments). This binding was also found in the presence of cell cultures, as revealed by HR-MAS NMR experiments. Conversely, no significant interaction with membranes was found with 3b or 3c. From both the unexpected solubility of 3c and 3a interactions with membranes, further chemical modifications were finally proposed.

In vitro effects of oxygen on physico-chemical properties of horse erythrocyte membrane.

Whether direct exposure to different concentrations (0%, 13%, 100%) of oxygen may affect horse erythrocyte membrane fluidity (EMF) and fatty acid (FA) composition was studied during 1 (T60) and 2h (T120) exposure. EMF was investigated at the head group level and hydrophobic core thanks to phosphorus nucleus 31 ((31)P) nuclear magnetic resonance ((31)P NMR) and electronic paramagnetic resonance (EPR) using two spin probes: 5-nitroxydestearic acid and 16-doxylstearic acid. Lipid structure of the membranes was studied by gas liquid chromatography. 4-Hydroxy-2E-nonenal was also analyzed as a marker of lipid peroxidation. It increased at T120 13% and 100% oxygen whereas there were no significant changes in membrane dynamic or structure. Correlation was demonstrated between EMF and partial pressure of oxygen in the blood ( [Formula: see text] ). In vitro high rate of oxygenation was efficient to induce lipid peroxidation but did not change membrane dynamics. This may be due to a low free radical production in vitro or to the high red blood cells antioxidant properties.

Acetylcholine release, EEG spectral analysis, sleep staging and body temperature studies: a multiparametric approach on freely moving rats.

We present a neurochemical, electrophysiological and physiological study on freely moving rats. During 3 days, we have simultaneously monitored acetylcholine (ACh) release in the hippocampus using the microdialysis technique, electroencephalogram (EEG), electromyogram (EMG) and subcutaneous temperature. A spectral analysis of EEG was performed and sleep stages were determined. Energy ratio in the delta (0-4 Hz), slow theta (4-6.5 Hz) and fast theta (6.5-9 Hz) band was calculated. Sleep stages were quantified using an automatic staging method. The circadian cycle of these parameters was observed. Waking, body temperature and ACh release presented synchronized cycles with close acrophases. The relationship between the central cholinergic system and the other parameters is discussed. The influence of handling on the measured parameters, as well as possible artifacts linked to the use of neostigmine in the microdialysis method are considered. Attention was focused on the cholinergic control of EEG theta rhythms.