1
|
Grissonnanche G, Legros A, Badoux S, Lefrançois E, Zatko V, Lizaire M, Laliberté F, Gourgout A, Zhou JS, Pyon S, Takayama T, Takagi H, Ono S, Doiron-Leyraud N, Taillefer L. Giant thermal Hall conductivity in the pseudogap phase of cuprate superconductors. Nature 2019; 571:376-380. [DOI: 10.1038/s41586-019-1375-0] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 04/26/2019] [Indexed: 11/09/2022]
|
2
|
Modolo J, Hassan M, Legros A. Probing brain networks to quantify the consciousness level: which role for ELF brain stimulation? Brain Stimul 2019. [DOI: 10.1016/j.brs.2018.12.364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
|
3
|
Legros A, Baker C, Corbacio M, Goulet D, Plante M, Souques M, Cabanes P, Deschamps F, Ostiguy G, Modolo J, Lambrozo J. Acute neurophysiological response to ELF-MF and magnetophosphene perception. Brain Stimul 2019. [DOI: 10.1016/j.brs.2018.12.670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
|
4
|
Testaert H, Mombrun M, Klein S, Fouquet H, Gérard M, Legros A, Ray A, Auzary C, Jeanjean C, Geffray L. Rémission transitoire sous ibrutinib d’un syndrome de Bing-Neel au cours d’une maladie de Waldenström. Rev Med Interne 2017. [DOI: 10.1016/j.revmed.2017.03.300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
5
|
Legros A, Modolo J, Corbacio M, Davarpanah Jazi S, Villard S, Goulet D, Plante M, Souques M, Deschamps F, Ostiguy G. Human acute neurophysiological responses to magnetically-induced alternating current densities of up to 100 mA.m-2. Brain Stimul 2017. [DOI: 10.1016/j.brs.2017.01.472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
|
6
|
Allen A, Corbacio M, Guerraz M, Goulet D, Plante M, Souques M, Deschamps F, Ostiguy G, Lambrozo J, Thomas A, Legros A. Étude des seuils de stimulations vestibulaires électriques et magnétiques modulant le contrôle postural. Neurophysiol Clin 2015. [DOI: 10.1016/j.neucli.2015.10.067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
|
7
|
Modolo J, Thomas AW, Legros A. Neural mass modeling of power-line magnetic fields effects on brain activity. Front Comput Neurosci 2013; 7:34. [PMID: 23596412 PMCID: PMC3622877 DOI: 10.3389/fncom.2013.00034] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 03/25/2013] [Indexed: 11/13/2022] Open
Abstract
Neural mass models are an appropriate framework to study brain activity, combining a high degree of biological realism while being mathematically tractable. These models have been used, with a certain success, to simulate brain electric (electroencephalography, EEG) and metabolic (functional magnetic resonance imaging, fMRI) activity. However, concrete applications of neural mass models have remained limited to date. Motivated by experimental results obtained in humans, we propose in this paper a neural mass model designed to study the interaction between power-line magnetic fields (MFs) (60 Hz in North America) and brain activity. The model includes pyramidal cells; dendrite-projecting, slow GABAergic neurons; soma-projecting, fast GABAergic neurons; and glutamatergic interneurons. A simple phenomenological model of interaction between the induced electric field and neuron membranes is also considered, along with a model of post-synaptic calcium concentration and associated changes in synaptic weights Simulated EEG signals are produced in a simple protocol, both in the absence and presence of a 60 Hz MF. These results are discussed based on results obtained previously in humans. Notably, results highlight that (1) EEG alpha (8-12 Hz) power can be modulated by weak membrane depolarizations induced by the exposure; (2) the level of input noise has a significant impact on EEG power modulation; and (3) the threshold value in MF flux density resulting in a significant effect on the EEG depends on the type of neuronal populations modulated by the MF exposure. Results obtained from the model shed new light on the effects of power-line MFs on brain activity, and will provide guidance in future human experiments. This may represent a valuable contribution to international regulation agencies setting guidelines on MF values to which the general public and workers can be exposed.
Collapse
Affiliation(s)
- J Modolo
- Human Threshold Research Group, Lawson Health Research Institute London, ON, Canada ; Department of Medical Biophysics, Western University London, ON, Canada ; Department of Medical Imaging, Western University London, ON, Canada
| | | | | |
Collapse
|
8
|
Legros A, Corbacio M, Beuter A, Modolo J, Goulet D, Prato FS, Thomas AW. Neurophysiological and behavioral effects of a 60 Hz, 1,800 μT magnetic field in humans. Eur J Appl Physiol 2011; 112:1751-62. [PMID: 21894451 DOI: 10.1007/s00421-011-2130-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Accepted: 08/12/2011] [Indexed: 11/29/2022]
Abstract
The effects of time-varying magnetic fields (MF) on humans have been actively investigated for the past three decades. One important unanswered question is the potential for MF exposure to have acute effects on human biology. Different strategies have been used to tackle this question using various physiological, neurophysiological and behavioral indicators. For example, researchers investigating electroencephalography (EEG) have reported that extremely low frequency (ELF, <300 Hz) MF can increase resting occipital alpha rhythm (8-12 Hz). Interestingly, other studies have demonstrated that human motricity can be modulated by ELF MF: a reduction of anteroposterior standing balance or a decrease of physiological tremor intensity have been reported as consequences of exposure. However, the main limitation in this domain lies in the lack of results replication, possibly originating from the large variety of experimental approaches employed. Therefore, the present study aimed to investigate the effects of a 60 Hz, 1,800 μT MF exposure on neurophysiological (EEG) and neuromotor (standing balance, voluntary motor function, and physiological tremor) aspects in humans using a single experimental procedure. Though results from this study suggest a reduction of human standing balance with MF exposure, as well as an increase of physiological tremor amplitude within the frequency range associated with central nervous system contribution, no exposure effect appeared on other investigated parameters (e.g., EEG or voluntary motor control). These results suggest that 1 h of 60 Hz, 1,800 μT MF exposure may modulate human involuntary motor control without being detected in the cortical electrical activity.
Collapse
Affiliation(s)
- A Legros
- Imaging Division, Lawson Health Research Institute, St Joseph's Health Care, 268 Grosvenor St, London, ON N6A 4V2, Canada.
| | | | | | | | | | | | | |
Collapse
|
9
|
Marshall HR, Stodilka RZ, Theberge J, Sabondjian E, Legros A, Deans L, Sykes JM, Thompson RT, Prato FS. A comparison of MR-based attenuation correction in PET versus SPECT. Phys Med Biol 2011; 56:4613-29. [PMID: 21725141 DOI: 10.1088/0031-9155/56/14/024] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Attenuation correction (AC) is a critical step in the reconstruction of quantitatively accurate positron emission tomography (PET) and single photon emission computed tomography (SPECT) images. Several groups have proposed magnetic resonance (MR)-based AC algorithms for application in hybrid PET/MR systems. However, none of these approaches have been tested on SPECT data. Since SPECT/MR systems are under active development, it is important to ascertain whether MR-based AC algorithms validated for PET can be applied to SPECT. To investigate this issue, two imaging experiments were performed: one with an anthropomorphic chest phantom and one with two groups of canines. Both groups of canines were imaged from neck to abdomen, one with PET/CT and MR (n = 4) and the other with SPECT/CT and MR (n = 4), while the phantom was imaged with all modalities. The quality of the nuclear medicine reconstructions using MR-based attenuation maps was compared between PET and SPECT on global and local scales. In addition, the sensitivity of these reconstructions to variations in the attenuation map was ascertained. On both scales, it was found that the SPECT reconstructions were of higher fidelity than the PET reconstructions. Further, they were less sensitive to changes to the MR-based attenuation map. Thus, MR-based AC algorithms that have been designed for PET/MR can be expected to demonstrate improved performance when used for SPECT/MR.
Collapse
Affiliation(s)
- H R Marshall
- The Lawson Health Research Institute, Imaging Program, London, Ontario, Canada.
| | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Pavlov AN, Tupitsyn AN, Legros A, Beuter A, Mosekilde E. Using wavelet analysis to detect the influence of low frequency magnetic fields on human physiological tremor. Physiol Meas 2007; 28:321-33. [PMID: 17322595 DOI: 10.1088/0967-3334/28/3/007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The influence of extremely low frequency magnetic fields (ELF-MFs) on human physiological processes and, in particular, on motor activity is still not established with certainty. Using the wavelet-transform approach, changes in the characteristics of human finger micromovement are studied in the presence of a low intensity MF centred at the level of the head. Different approaches to nonstationary signal analysis involving real as well as complex wavelet functions are considered. We find evidence that ELF-MFs lead to more regular postural tremor and more homogeneous energy distribution.
Collapse
Affiliation(s)
- A N Pavlov
- Department of Physics, Saratov State University, Astrakhanskaya Str 83, Saratov, Russia.
| | | | | | | | | |
Collapse
|
11
|
Faure D, Maleville X, Hipeaux JC, Legros A. Oxydation des huiles de bases minérales d'origine pétrolière. Relation entre leur composition chimique, l'épaississement et la composition de leur produits de dégradation. ACTA ACUST UNITED AC 2006. [DOI: 10.2516/ogst:1995027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
12
|
Abstract
INTRODUCTION Quantification of motor functions of patients with dystonic syndromes treated by chronic high frequency stimulation of the internal globulus pallidus is a challenge. OBJECTIVE Through a series of clinical examples this paper shows that kinematic analysis of movements in dystonic syndromes treated by deep brain stimulation (DBS) is a complement to clinical evaluation. In addition, it provides valuable information for early detection of improvement or impairment of movements associated with modifications of stimulation parameters. METHOD Thirteen dystonic patients and eleven reference subjects completed three tests (i.e., rest: lying supine; posture: standing with arms held in front (at shoulder height); and alternative movements: bimanual finger-to-nose test). These tests were recorded with an electromagnetic system quantifying movement kinematics (position) in three-dimensional space. RESULTS From the recorded data, several indices were developed and provided a quantitative evaluation of movements during each test. In addition, a clinical evaluation (BMFDRS) was also completed. No correlation between clinical and kinematic evaluations was found. CONCLUSION It is shown that kinematic analysis is a useful complement of clinical evaluation and can assist clinicians in monitoring the evolution of movements in dystonic patients treated by DBS in a simple, reliable and valid fashion.
Collapse
Affiliation(s)
- A Legros
- Equipe d'Accueil 2991: Efficience et Déficience Motrices, Montpellier
| | | | | | | | | |
Collapse
|
13
|
Legros A, Diakonova N, Cif L, Hemm S, Vayssière N, Coubes P, Beuter A. Accelerometric measurement of involuntary movements during pallidal deep brain stimulation of patients with generalized dystonia. Brain Res Bull 2004; 64:363-9. [PMID: 15561472 DOI: 10.1016/j.brainresbull.2004.09.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2003] [Accepted: 09/13/2004] [Indexed: 10/26/2022]
Abstract
Accelerometric activity during rest and posture was quantified in the upper dominant limb of 14 patients with primary or secondary dystonia and five healthy control subjects. Data were recorded before and after bilateral implantation of the stimulating electrodes in the Globus Pallidus internus. Clinical evaluation was based on the Burke-Marsden-Fahn's Dystonia Rating Scale (BMFDRS). For the patient group, I(t), the integral (i.e. area) of the acceleration power spectrum over the total frequency range (0.6-16 Hz) decreased as the clinical state of the patients improved following deep brain stimulation (p < 0.01) during rest and posture. Ten days after surgery, there were no I(t) differences between control subjects and patients (p > 0.05). A significant correlation was found between the global BMFDRS scores and I(t) for rest (p < 0.01) but not for posture. No significant correlation was found between I(t) and a partial BMFDRS score for the right arm for rest or posture. The integral I(t) provides a valid indicator of the motor activity generated by the arm of the patient but further analyses are needed to monitor patients' progress not only during their hospitalization but also after they are released from the hospital, and to understand why this measure does not correlate with partial BMFDRS scores.
Collapse
Affiliation(s)
- A Legros
- Efficience et Déficience Motrice (EA 2991) and Department of Pediatric Neurosurgery (Research Unit on Movement Disorders in Children), University Hospital Gui de Chauliac, Montpellier, France
| | | | | | | | | | | | | |
Collapse
|
14
|
Faure D, Hipeaux JC, Guevellou Y, Legros A. Oxidation stability of gasoline engine lubricants: Effect of base-oil chemistry in laboratory and engine tests. ACTA ACUST UNITED AC 1999. [DOI: 10.1002/tt.3020050402] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
15
|
Legros A, Carreau P, Favis B, Michel A. Morphology modification by interfacial chemical reaction in a polyester/ethylene vinyl acetate/polyethylene blend. POLYMER 1997. [DOI: 10.1016/s0032-3861(97)00033-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
16
|
Donandieu AM, Idee JM, Doucet D, Legros A, Penati S, Nain-Dit-Ducret M, Marmion F, Bonnemain B. Toxicologic profile of iobitridol, a new nonionic low-osmolality contrast medium. Acta Radiol Suppl 1996; 400:17-24. [PMID: 8619348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
PURPOSE The toxicologic profile of iobitridol, a new nonionic low-osomolality contrast medium, was evaluated in compliance with the current regulatory requirements in Europe, the USA and Canada. MATERIAL AND METHODS The toxicity of iobitridol was tested following acute or repeated i.v. administration in several different species (mouse, rat, dog); single oral administration in the mouse and intracisternal injection in the rat. Furthermore, teratogenicity and mutagenicity were evaluated in the rat and rabbit. Local perivenous toxicity was assessed in the rabbit. RESULTS The acute toxicity of iobitridol in the mouse is equivalent to that of iohexol, a reference product tested under the same conditions. Chronic administration (daily injections i.v. injection over 4 weeks) in the rat and dog did not demonstrate any particular toxicity for iobitridol. It should be noted that, unlike iohexol, iobitridol did not provoke any vacuolization of the renal tubular cells in the rat following repeated injections. Furthermore, this contrast agent did not show any teratogenic or mutagenic potential. The typical local inflammatory signs observed following perivenous injection in the rabbit were low in intensity and reversible. CONCLUSION The toxicologic profile of iobitridol appears to be favorable and does not show any particular risk for clinical use under the usual indications of water soluble iodinated contrast agents.
Collapse
Affiliation(s)
- A M Donandieu
- Research Center, Laboratoire Guerbet, Aulnay-sous-Bois, France
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Legros A, Carreau P, Favis B, Michel A. Reactive compatibilization of polyester/vinyl acetate copolymer blends: rheological, morphological and mechanical properties. POLYMER 1994. [DOI: 10.1016/0032-3861(94)90873-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
18
|
Reux I, Legros A, Le Hoang P. [Preparation of the patient for ophthalmologic surgery]. Rev Infirm 1992; 42:30-3. [PMID: 1561518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
|
19
|
Levy E, Parc R, Bloch P, Legros A, Hannoun L, Nordlinger B, Huguet C, Loygue J. [Transorificial intubation with direct neutralization of the digestive juices in cases of gastric or duodenal lesions. Principle and application of a new treatment for severe postoperative peritonitis of a gastric or duodenal origin (twenty-one cases) ]. Ann Chir 1982; 36:419-423. [PMID: 7125555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
|
20
|
Legros A, Baux D, Leclère J, Malafosse M. [Echotomographic diagnosis of multiple abscesses of the kidney]. Nouv Presse Med 1981; 10:912. [PMID: 7208301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
|
21
|
Benomar S, Bouziane M, Legros A, Ohayon V. [A new case of Dubin-Johnson disease]. Maghrib Tibbi 1980; 2:451-5. [PMID: 7345237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
|
22
|
Legros A, Leconte D, Huguet C. [Intestinal pseudo-obstruction due to ganglioneuromatosis (author's transl)]. Gastroenterol Clin Biol 1980; 4:333-7. [PMID: 7399200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
|
23
|
Loygue J, Michot F, Legros A. [Repair of perineal eventration following excision of the rectum, using the lumbo-ovarian ligaments]. Nouv Presse Med 1979; 8:3897. [PMID: 548919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
24
|
Parc R, Legros A, Huguet C, Malafosse M, Bloch P, Gallot D, Loygue J. [Hepatic embolizations and dearterializations. Apropos of 32 cases]. Ann Chir 1978; 32:713-9. [PMID: 749657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|
25
|
Malafosse M, Legros A. [Treatment and prognosis of gastric adenocarcinoma]. Rev Prat 1978; 28:3485-92. [PMID: 82992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
26
|
Blondeau P, Legros A, René L. [Is unilateral total lobectomy adequate treatment for a single malignant thyroid nodule? 67 patients operated upon between 5 and 18 years age (author's transl)]. Nouv Presse Med 1977; 6:2583-7. [PMID: 333385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In the treatment of thyroid carcinoma, there is still some discussion about the best operation for a solitary and well encapsulated nodule. 18 years ago, it was decided to treat every case of "cold" thyroid nodule by total lobectomy and isthmectomy. 56 patients were reevaluated 5 to 18 years after such limited operation for malignant nodules. 8 of them died between the 19 th month and the 14 th year after surgery, the death being possibly related to the thyroid cancer in only 4 patients, but without any clinical evidence of local recurrence. Among 50 surviving patients, only one controlateral recurrence was observed, two years after lobectomy; it was treated by surgical totalisation of thyroidectomy, without any new recurrence after 10 more years. These results (although the small number of cases, and too short follow-up exclude definitive conclusions) are comparable to those obtained by a more aggresive surgical approach, but have the great advantage of total absence of any functional sequellae. So are we encouraged to go further in the experience of a rather conservative surgery in the treatment of uninodular thyroid carcinoma.
Collapse
|
27
|
Blondeau P, Legros A, Rene L. [The hemorrhagic risk in surgery of the thyroid gland]. Ann Chir 1975; 29:519-27. [PMID: 1163967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|