P Arbeille

University of Waterloo, Waterloo, Ontario, Canada

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Publications (135)140.24 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: This study tested the hypothesis that cardiovascular effects of sublingual nitroglycerin (NG) would be exaggerated after 56 days of 6° head-down bed rest (HDBR) in women, and that an aerobic and resistive exercise countermeasure (EX, n = 8) would reduce the effect compared with HDBR without exercise (CON, n = 7). Middle cerebral artery maximal blood flow velocity (CBFV), cardiac stroke volume (SV), and superficial femoral artery blood flow (Doppler ultrasound) were recorded at baseline rest and for 5 min following 0.3 mg sublingual NG. Post-HDBR, NG caused greater increases in heart rate (HR) in CON compared with EX (+24.9 ± 7.7 and +18.8 ± 6.6 beats/min, respectively, P < 0.0001). The increase in HR combined with reductions in SV to maintain cardiac output. Systolic, mean, and pulse pressures were reduced 5-10 mmHg by NG, but total peripheral resistance was only slightly reduced at 3 min after NG. Reductions in CBFV of -12.5 ± 3.8 cm/s were seen after NG, but a reduction in the Doppler resistance index suggested dilation of the middle cerebral artery with no differences after HDBR. The femoral artery dilated with NG and blood flow was reduced ∼50% with the appearance of large negative waves suggesting a marked increase in downstream resistance, but there were no effects of HDBR. In general, responses of women to NG were not altered by HDBR; the greater increase in HR in CON but not EX was probably a consequence of cardiovascular deconditioning. These results contrast with the hypothesis and a previous investigation of men after HDBR by revealing no change in cardiovascular responses to exogenous nitric oxide.
    Journal of Applied Physiology 05/2012; 113(3):434-41. · 3.43 Impact Factor
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    ABSTRACT: Early evidence from long-duration flights indicates general cardiovascular deconditioning, including reduced arterial baroreflex gain. The current study investigated the spontaneous baroreflex and markers of cardiovascular control in six male astronauts living for 2-6 mo on the International Space Station. Measurements were made from the finger arterial pressure waves during spontaneous breathing (SB) in the supine posture pre- and postflight and during SB and paced breathing (PB, 0.1 Hz) in a seated posture pre- and postflight, as well as early and late in the missions. There were no changes in preflight measurements of heart rate (HR), blood pressure (BP), or spontaneous baroreflex compared with in-flight measurements. There were, however, increases in the estimate of left ventricular ejection time index and a late in-flight increase in cardiac output (CO). The high-frequency component of RR interval spectral power, arterial pulse pressure, and stroke volume were reduced in-flight. Postflight there was a small increase compared with preflight in HR (60.0 ± 9.4 vs. 54.9 ± 9.6 beats/min in the seated posture, P < 0.05) and CO (5.6 ± 0.8 vs. 5.0 ± 1.0 l/min, P < 0.01). Arterial baroreflex response slope was not changed during spaceflight, while a 34% reduction from preflight in baroreflex slope during postflight PB was significant (7.1 ± 2.4 vs. 13.4 ± 6.8 ms/mmHg), but a smaller average reduction (25%) during SB (8.0 ± 2.1 vs. 13.6 ± 7.4 ms/mmHg) was not significant. Overall, these data show no change in markers of cardiovascular stability during long-duration spaceflight and only relatively small changes postflight at rest in the seated position. The current program routine of countermeasures on the International Space Station provided sufficient stimulus to maintain cardiovascular stability under resting conditions during long-duration spaceflight.
    Journal of Applied Physiology 12/2011; 112(5):719-27. · 3.43 Impact Factor
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    ABSTRACT: The objective of this study is to assess by echography and Doppler the Cerebral (Vmca), Aortic (Vao) and Femoral (Vfem) arterial flow velocity and calf vein (Tibial, Gastrocnemius) section (Tib, Gast) during orthostatic intolerance (OI) test after a 60-day, head down tilt bed rest (HDBR). Twenty-four women (25-40 years) underwent a 60-day HDBR at -6°: eight as control (Con), eight with exercise against lower body negative pressure (Ex-Lb) and eight with nutrition supplement (Nut). Before and after (R0) HDBR, all subjects underwent a 10-min, 80° tilt followed by progressive LBNP until presyncope. After the post-HDBR Tilt + LBNP test, two groups were identified: finishers (F, n = 11) who completed the Tilt and non-finishers (NF, n = 13). A higher percentage decrease in Vao flow, higher percentage distension of Tib vein and a lack of increase in Vmca/Vfem ratio during the post-HDBR Tilt + LBNP compared to pre-HDBR were correlated to OI, but not all of these abnormal responses were present in each of the NF subjects. Abnormal responses were more frequent in Con and Nut than in Ex-Lb subjects. (1) HDBR did not affect the cardiac, arterial and venous responses to the orthostatic test to the same extent in each subject. (2) Exercise within LBNP partially preserved the cardiovascular response to Tilt, while Nutrition supplementation had no efficacy. (3) Cerebral/femoral flow ratio and aortic flow were the parameters most closely related to OI. (4) Reduction in aortic flow was not the major hemodynamic change preceding syncope.
    Arbeitsphysiologie 05/2011; 112(1):277-84. · 2.30 Impact Factor
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    ABSTRACT: We quantified the impact of a 60-day head-down tilt bed rest (HDBR) with countermeasures on the arterial response to supine lower body negative pressure (LBNP). Twenty-four women [8 control (Con), 8 exercise + LBNP (Ex-LBNP), and 8 nutrition (Nut) subjects] were studied during LBNP (0 to -45 mmHg) before (pre) and on HDBR day 55 (HDBR-55). Left ventricle diastolic volume (LVDV) and mass, flow velocities in the middle cerebral artery (MCA flow) and femoral artery (femoral flow), portal vein cross-sectional area (portal flow), and lower limb resistance (femoral resistance index) were measured. Muscle sympathetic nerve activity (MSNA) was measured in the fibular nerve. Subjects were identified as finishers or nonfinishers of the 10-min post-HDBR tilt test. At HDBR-55, LVDV, mass, and portal flow were decreased from pre-HDBR (P < 0.05) in the Con and Nut groups only. During LBNP at HDBR-55, femoral and portal flow decreased less, whereas leg MSNA increased similarly, compared with pre-HDBR in the Con, Nut, and NF groups; 11 of 13 nonfinishers showed smaller LBNP-induced reductions in both femoral and portal flow (less vasoconstriction), whereas 10 of 11 finishers maintained vasoconstriction in either one or both regions. The relative distribution of blood flow in the cerebral versus portal and femoral beds during LBNP [MCA flow/(femoral + portal flow)] increased or reduced < 15% from pre-HDBR in 10 of 11 finishers but decreased > 15% from pre-HDBR in 11 of 13 nonfinishers. Abnormal vasoconstriction in both the portal and femoral vascular areas was associated with orthostatic intolerance. The vascular deconditioning was partially prevented by Ex-LBNP.
    AJP Heart and Circulatory Physiology 09/2008; 295(5):H1846-54. · 4.01 Impact Factor
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    ABSTRACT: The objective of this paper is to design and validate a method for tele-operating (from an expert site) an echographic examination in an isolated site where the patient stays. A dedicated robotic arm (ESTELE) holding a real ultrasound probe is remotely controlled from the expert site with a fictive probe, and reproduces on the real probe all the movements of the expert hand. The isolated places, are areas with reduced medical facilities, secondary hospitals 20 to 100 km from the main hospital in Europe, dispensaries in Africa, Amazonia, the a rescue vehicles. ESTELE was tested on 87 adults and 29 pregnant with ISDN or satellite lines. During fetal tele-operated echography the expert was able to perform appropriate views of the fetal structures in 95% of the cases. During exploration of adult abdomen the expert visualized the main organs in 87% of the cases. Presently the ESTELE system is installed in 4 secondary hospitals, 40 to 100 km from our university hospital and tele-operated daily by our staff. Robotized tele-echography provide similar information as direct examination. No false diagnostic was reported. Moreover the patients were examined by an expert from the university hospital while staying in the Medical center proximal to their home.
    Automation, Quality and Testing, Robotics, 2008. AQTR 2008. IEEE International Conference on; 06/2008
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    ABSTRACT: The objective of this study was to quantify by echography the changes in the intramuscular [gastrocnemius (Gast)] and nonintramuscular [posterior tibial (Tib)] calf veins cross-sectional area (CSA) and the superficial tissue thickness (STth) in response to lower body negative pressure (LBNP) after 60-day head-down bed rest (HDBR). Twenty-four healthy women (25-40 yr) were divided into three groups: control (Con), treadmill-LBNP and flywheel (Ex-Lb), nutrition (Nut; protein supplement). All underwent a LBNP (0 and -45 mmHg) before and on day 55 of HDBR. Subjects were identified as finisher (F) or nonfinisher (NF) of a 10-min tilt test after 60 days of HDBR. There were no differences in resting CSA of the Tib and Gast veins on HDBR day 55 compared with pre-HDBR for the Ex-Lb, Con and Nut, or the F groups; however, for NF both the Tib and Gast vein CSA at rest were significantly smaller after HDBR. At -45 mmHg LBNP, Tib and Gast CSAs were not significantly different from before HDBR in all groups (Ex-Lb, Con, Nut, F, NF). However, percent change in CSA of both veins from rest to -45 mmHg LBNP was significantly greater in the Con and Nut groups compared with Ex-Lb, and also NF compared with F. Similarly, the percent increase in STth on going from rest to -45 mmHg was higher after HDBR in the Con and Nut groups compared with Ex-Lb, as well as NF compared with F. These results showed that the Ex-Lb countermeasure minimized the bed rest effect on leg vein capacitance (CSA percent change) and STth increase during LBNP, whereas Nut had no effect and that higher leg vein and superficial tissue capacitance were associated with reduced orthostatic tolerance.
    Journal of Applied Physiology 05/2008; 104(4):938-43. · 3.43 Impact Factor
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    ABSTRACT: This study tested the hypothesis that cardiovascular and hormonal responses to lower body negative pressure (LBNP) would be altered by 4-h head down bed rest (HDBR) in 11 healthy young men. In post-HDBR testing, three subjects failed to finish the protocol due to presyncopal symptoms, heart rate was increased during LBNP compared with pre-HDBR, mean arterial blood pressure was elevated at 0, -10, and -20 mmHg and reduced at -40 mmHg, central venous pressure (CVP) and cardiac stroke volume were reduced at all levels of LBNP. Plasma concentrations of renin, angiotensin II, and aldosterone were significantly lower after HDBR. Renin and angiotensin II increased in response to LBNP only post-HDBR. There was no effect of HDBR or LBNP on norepinephrine while epinephrine tended to increase at -40 mmHg post-HDBR (P = 0.07). Total blood volume was not significantly reduced. Splanchnic blood flow taken from ultrasound measurement of the portal vein was higher at each level of LBNP post-compared with pre-HDBR. The gain of the cardiopulmonary baroreflex relating changes in total peripheral resistance to CVP was increased after HDBR, but splanchnic vascular resistance was actually reduced. These results are consistent with our hypothesis and suggest that cardiovascular instability following only 4-h HDBR might be related to altered hormonal and/or neural control of regional vascular resistance. Impaired ability to distribute blood away from the splanchnic region was associated with reduced stroke volume, elevated heart rate, and the inability to protect mean arterial pressure.
    Journal of Applied Physiology 01/2008; 103(6):2018-25. · 3.43 Impact Factor
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    ABSTRACT: Accurate measurement of beat-to-beat arterial blood pressure is essential for understanding the cardiovascular adaptation to weightlessness; however, the intra-arterial standard of beat-to-beat blood pressure measurement has never been used during space flight because of its invasive nature. The aim of the present study was to compare noninvasive radial artery tonometry blood pressure measurement with intra-radial pressure measurement during microgravity and hypergravity generated by parabolic flights. Two study participants, equipped with an intra-radial pressure line on the left arm and a Colin CBM-7000 (Colin Corp., Komaki City, Japan) beat-to-beat pressure measurement apparatus on the right arm, were studied in a supine position, during parabolic flights on board of the Airbus A300 OG of the Centre National d'Etudes Spatiales. The mean and standard deviations of the beat-to-beat difference between tonometric and intra-radial blood pressure were calculated for systolic and diastolic arterial pressure in the three gravity conditions (1g, 0 g and 1.8 g) experienced during parabolic flight. The Colin CBM-7000 met the specifications required by the Association for the Advancement of Medical Instrumentation in the 0 g environment. Gravity, however, significantly affected the difference between tonometric and intra-arterial blood pressure, possibly owing to the effect of gravity on the apparent weight of the device and the corresponding calibration factor. We conclude that the Colin CBM-7000 can be used with confidence during space flight.
    Blood Pressure Monitoring 01/2008; 12(6):357-62. · 1.18 Impact Factor
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    ABSTRACT: Twenty-four (24) healthy women from 25-40 years of age underwent orthostatic tolerance tests consisting of passive tilt and lower body negative pressure before and after completing 60-days of continuous -6 degree head down tilt bed rest (HDBR). Prior to HDBR, participants were assigned to one of three groups: control, exercise or nutrition. We aimed to identify any acute head up tilt changes in mean arterial pressure, pulse pressure, total peripheral resistance, cardiac output, stroke volume, or heart rate, which might predict tolerance or changes in tolerance with HDBR. Generally, these attempts were largely unsuccessful. The results indicate that the mechanisms of orthostatic failure are not strongly related to the way in which the body responds to the initial challenge. Additionally, the observation that some variables were predictive of tolerance before and not after tilt may indicate a change in the strategies used to maintain blood pressure, or differential adaptations to HDBR.
    Journal of gravitational physiology: a journal of the International Society for Gravitational Physiology 08/2007; 14(1):P63-4.
  • D K Greaves, P Arbeille, R L Hughson
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    ABSTRACT: We tested the hypothesis that 60 days of head-down bed rest (HDBR) would affect cerebrovascular autoregulation and that this change would be correlated with changes in tolerance to the upright posture. Twenty-four healthy women (32 +/- 4 yrs) participated in a 60-d bed rest study at the MEDES Clinic in Toulouse, France. End tidal CO2 (ETCO2), continuous blood pressure (BP), middle cerebral artery (MCA) velocity and time to presyncope (endpoint) were measured during an orthostatic tolerance test conducted before/after bed rest. Given the large range of change in tolerance even within assigned countermeasure groups, we separated subjects for this analysis on the basis of the change in endpoint (Delta endpoint) pre- to post-bed rest. Autoregulation and CO2 responsiveness were evaluated on a different day from a two-breath test with intermittent hypercapnic exposure. Autoregressive moving average (ARMA) modeled the two confounding inputs, BP and CO2, on cerebrovascular blood flow. The cerebrovascular resistance index (CVRi) was expected to decrease following a decrease in BP at the MCA to assist in maintenance of cerebral blood flow. Subjects with the smallest Delta endpoint after bed rest had a 78% increase in the gain of the BP --> CVRi response. Meanwhile, the groups with greater decline in orthostatic tolerance post-HDBR had no change in the gain of this response. ETCO2 was lower overall following HDBR, decreasing from 41.8 +/- 3.4 to 40.2 +/- 3.0 in supine rest, 37.9 +/- 3.4 to 33.3 +/- 4.0 in early tilt, and 29.5 +/- 4.4 to 27.1 +/- 5.1 at pre-syncope. There was however, higher MCA velocity at any ETCO2 for post- compared to pre-HDBR. In summary, changes in autoregulation were found only in those subjects who had the smallest change from pre- to post-HDBR orthostatic tolerance. The changes may assist in buffering changes in cerebral blood flow during orthostatic hypotension post-HDBR. The reduction in ETCO2 after bed rest might be due to a change in chemoreceptor response to blood CO2, but the cerebrovascular system seems to have completely compensated.
    Journal of gravitational physiology: a journal of the International Society for Gravitational Physiology 08/2007; 14(1):P61-2.
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    ABSTRACT: The objective was to quantify the Cerebral, and Femoral arterial hemodynamics as well as the calf vein section changes induced by a Tilt up test continuing with a Tilt plus LBNP after a 60 day HDT (WISE). 24 healthy volunteers (25-40 y) underwent a 60 day HDT (-6 degree) bedrest: 8 as Control (Co), 8 with Exercise (Ex: treadmill under LBNP and flywheel), 8 with Nutrition (Nut: daily protein supplement). At R+0 all of them underwent a 10 min 80 degree Tilt up test, to which several LBNP period of 3 min were added (from -10 to -50 mmHg by steps of 10 mmHg) until presyncopal stage. Cerebral and Femoral flow changes were assessed by Doppler. Posterior Tibial, and Gastrocnemian vein were investigated by echography. At Post HDT 10 min Tilt: cerebral flow decreased similarly in the 3 groups, but more in the non finishers than in the finishers, while the femoral decreased similarly in all groups. Leg vascular resistance and cerebral/femoral flow ratio increased less in the Co and Nut gr than in the Ex gr, and also in the non finishers than in the finishers. Percent increase in Gastrocnemian and Tibial section was higher in Co and Nut gr than in Ex gr, and in non finishers than in finishers. Non exercise and non finisher subjects showed a lack of leg vasoconstriction, and a higher calf vein distensibility at post HDT Tilt test.
    Journal of gravitational physiology: a journal of the International Society for Gravitational Physiology 08/2007; 14(1):P47-8.
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    ABSTRACT: The objective was to quantify calf vein cross section area (CSA) maximal enlargement and the percent change in response to LBNP (lower body negative pressure) after a 60 day bedrest. The 24 healthy volunteers (25-40 y) of the WISE 60 day HDT(-6 degree) bedrest, were divided into 3 groups: Control (Co), Exercise countermeasure (Ex: treadmill under LBNP and flywheel), Nutrition (Nut: daily protein supplement). All were studied at -45mmHg LBNP pre and at HDT day 55. Posterior Tibial (Tib), and Gastrocnemian (Gast) vein were investigated by echography using an echographic probe fixed at the upper and posterior part of the calf. From the post HDT CSE test the subjects were identified as finisher or non finisher to the 10-min tilt tolerance test. At LBNP-45mmHg, the maximal enlargement of the Tib and Gast veins remained constant pre, and at HDT day 55 in all group (Co, Ex, Nut, finisher, non finisher). For both veins there was a higher vein distension (percent change from supine rest to -45mmHg) in Co and Nut group compared to Ex group despite the maximal distension was similar in all groups. Also the vein distension was higher in non finisher than in finisher. The maximal distension of the vein were not affected nor by HDT nor by CM. The Ex counter-measure minimized the bed rest effect on leg vein distensibility (percent CSA change) while the Nut countermeasure had no effect. Higher leg vein distensibility was associated with reduced orthostatic tolerance.
    Journal of gravitational physiology: a journal of the International Society for Gravitational Physiology 08/2007; 14(1):P57-8.
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    ABSTRACT: The objective of the present study was to quantify the effects of elastic compression stockings (ECS) on the leg hemodynamics, the venous return (flow and distensibility) and on the leg superficial tissue thickness. 10 healthy women were submitted to LBNP (Lower Body Negative Pressure) tests without then with ECS (French pressure class 1, 2 and 3). The subject was instrumented with Doppler and echographic probes for assessing the femoral artery, the external saphenous and the gastrocnemian vein. 1) At -40 mmHg the heart rate and blood pressure didn't change significantly with or without ECS. 2) The lower limb vascular resistance increased by 20 to 25% (p<0.01) from the initial values (i.e. without depressure) without or with class 1 or 2 ECS, while it increased less (13%, p<0.01) with class 3 ECS. 3) With ECS, the gastrocnemian vein area was reduced by 10 to 15% (p<0.01) from the initial values, in proportion to the ECS class. 4) The maximal distension (cross section) of this vein at -40 mmHg remained similar with or without ECS, but the percent change in vein distension was significantly higher with ECS than without. 5) Only without ECS, the distance between the external saphenous vein and the skin increased by 13% at -40 mmHg (p<0.01) from the initial values (increase of the calf peripheral area by 11% p<0.01). With ECS, there was no increase in distance nor area during LBNP. ECS had no effect on the main arterial hemodynamics and venous cross section area, while it prevented liquid stowage into the superficial tissue.
    Journal of gravitational physiology: a journal of the International Society for Gravitational Physiology 08/2007; 14(1):P59-60.
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    ABSTRACT: The mechanism of the pressor response to small muscle mass (e.g., forearm) exercise and during metaboreflex activation may include elevations in cardiac output (Q) or total peripheral resistance (TPR). Increases in Q must be supported by reductions in visceral venous volume to sustain venous return as heart rate (HR) increases. Therefore, this study tested the hypothesis that increases in Q, supported by reductions in splanchnic volume (portal vein constriction), explain the pressor response during handgrip exercise and metaboreflex activation. Seventeen healthy women performed 2 min of static ischemic handgrip exercise and 2 min of postexercise circulatory occlusion (PECO) while HR, stroke volume and superficial femoral artery flow (Doppler), blood pressure (Finometer), portal vein diameter (ultrasound imaging), and muscle sympathetic nerve activity (MSNA; microneurography) were measured followed by the calculation of Q, TPR, and leg vascular resistance (LVR). Compared with baseline, mean arterial blood pressure (MAP) (P < 0.001) and Q (P < 0.001) both increased in each minute of exercise accompanied by a approximately 5% reduction in portal vein diameter (P < 0.05). MAP remained elevated during PECO, whereas Q decreased below exercise levels. MSNA was elevated above baseline during the second minute of exercise and through the PECO period (P < 0.05). Neither TPR nor LVR was changed from baseline during exercise and PECO. The data indicate that the majority of the blood pressure response to isometric handgrip exercise in women was due to mobilization of central blood volume and elevated stroke volume and Q rather than elevations in TVR or LVR resistance.
    Journal of Applied Physiology 07/2007; 103(1):228-33. · 3.43 Impact Factor
  • The Third IASTED International Conference on Telehealth; 05/2007
  • Journal de Radiologie 10/2006; 87(10):1380-1380. · 0.57 Impact Factor
  • Journal de Radiologie 10/2006; 87(10):1380-1380. · 0.57 Impact Factor
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    Ultrasound in Obstetrics and Gynecology 08/2006; 28(4):462 - 462. · 3.56 Impact Factor
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    Ultrasound in Obstetrics and Gynecology 08/2006; 28(4):461 - 461. · 3.56 Impact Factor
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    Ultrasound in Obstetrics and Gynecology 08/2006; 28(4):458 - 459. · 3.56 Impact Factor

Publication Stats

659 Citations
140.24 Total Impact Points


  • 2007–2012
    • University of Waterloo
      • Faculty of Applied Health Sciences
      Waterloo, Ontario, Canada
    • The University of Western Ontario
      • Department of Physiology and Pharmacology
      London, Ontario, Canada
  • 1992–2011
    • University of Tours
      Tours, Centre, France
    • German Aerospace Center (DLR)
      • Institute of Aerospace Medicine
      Köln, North Rhine-Westphalia, Germany
  • 1988–2004
    • Unité Inserm U1077
      Caen, Lower Normandy, France
  • 2003
    • Université d'Orléans
      Orléans, Centre, France
  • 2001–2002
    • Centre Hospitalier Universitaire de Tours
      Tours, Centre, France
    • Centre Hospitalier Universitaire de Nice
      • Département de Gynécologie
      Nice, Provence-Alpes-Côte d'Azur, France
  • 1998
    • Oregon State University
      • Department of Food Science and Technology
      Corvallis, OR, United States
    • University Hospital Estaing of Clermont-Ferrand
      Clermont, Auvergne, France
  • 1997–1998
    • French Institute of Health and Medical Research
      Lutetia Parisorum, Île-de-France, France
  • 1995
    • Claude Bernard University Lyon 1
      • Département de biologie
      Villeurbanne, Rhône-Alpes, France