Cosmological Plebanski theory

We consider the cosmological symmetry reduction of the Plebanski action as a toy-model to explore, in this simple framework, some issues related to loop quantum gravity and spin-foam models. We make the classical analysis of the model and perform both path integral and canonical quantizations. As for the full theory, the reduced model admits two types of classical solutions: topological and gravitational ones. The quantization mixes these two solutions, which prevents the model to be equivalent to standard quantum cosmology. Furthermore, the topological solution dominates at the classical limit. We also study the effect of an Immirzi parameter in the model.Comment: 20 page

La recherche en éducation médicale dans les facultés de médecine en France. Etat des lieux à partir d’une revue systématique des travaux publiés

Introduction : La recherche en éducation des professionnels de santé est une jeune discipline scientifique se développant dans de nombreux pays. L’objectif de ce travail était d’établir un état des lieux quantifié et objectif de cette activité de recherche en France, au regard des travaux publiés par les facultés de médecine. Méthode : Une revue systématique sur 15 ans a été réalisée à partir de deux bases de données : Pubmed et les archives de la revue Pédagogie Médicale. Résultats : L’activité de recherche en éducation médicale dans les facultés de médecine françaises, telle qu’elle peut être mesurée par sa production scientifique, est en nette progression en France (multipliée par 12 en 15 ans), bien qu’en retard par rapport à d’autres pays comme le Canada ou, plus proche, l’Allemagne. Toutes thématiques confondues, la contribution française à la recherche en éducation médicale est de 0,22 % dans Pubmed et 21 % dans la revue Pédagogie Médicale. La gynécologie, l’obstétrique, l’anesthésie réanimation et des disciplines transversales comme la santé publique, la médecine interne, la médecine générale et la médecine d’urgence sont celles qui investissent le plus ce champ de recherche. La majorité des travaux sont axés sur l’évaluation des résultats de dispositifs d’enseignement. Malgré des facteurs d’impacts le plus souvent inférieurs à 4, le niveau de publication selon la classification SIGAPS reste élevé avec la moitié des travaux publiés dans des revues A, B ou C. Discussion : Malgré une nette augmentation ces dernières années, cette faible implication des équipes françaises est possiblement le reflet de la méconnaissance de ce champ disciplinaire, d’un manque de formation des chercheurs aux spécificités de la recherche dans ce domaine et du manque d’équipes françaises cherchant à y développer une recherche fondamentale et appliquée de bon niveau scientifique. Conclusion : La recherche française en éducation médicale reste à développer en France. La formation de leaders dans le domaine et la création de centres de recherche en pédagogie médicale semblent indispensables

Study of the Long-Term Results of Decompressive Craniectomy after Severe Traumatic Brain Injury Based on a Series of 60 Consecutive Cases

Background. Decompressive craniectomy can be proposed in the management of severe traumatic brain injury. Current studies report mixed results, preventing any clear conclusions on the place of decompressive craniectomy in traumatology. Methods. The objective of this retrospective study was to evaluate the results of all decompressive craniectomies performed between 2005 and 2011 for refractory intracranial hypertension after severe traumatic brain injury. Sixty patients were included. Clinical parameters (Glasgow scale, pupillary examination) and radiological findings (Marshall CT scale) were analysed. Complications, clinical outcome, and early and long-term Glasgow Outcome Scale (GOS) were evaluated after surgery. Finally, the predictive value of preoperative parameters to guide the clinician’s decision to perform craniectomy was studied. Results. Craniectomy was unilateral in 58 cases and the mean bone flap area was 100 cm2. Surgical complications were observed in 6.7% of cases. Mean followup was 30 months and a favourable outcome was obtained in 50% of cases. The initial Glasgow Scale was the only statistically significant predictive factor for long-term outcome. Conclusion. Despite the discordant results in the literature, this study demonstrates that decompressive craniectomy is useful for the management of refractory intracranial hypertension after severe traumatic brain injury

Meningiomas and cyproterone acetate: a retrospective, monocentric cohort of 388 patients treated by surgery or radiotherapy for intracranial meningioma

International audiencePurpose Meningiomas are the most common intracranial tumors, accounting for 20-30% of central nervous system tumors. Recently, the European Medicines Agency issued an alert on cyproterone acetate (CPA) based on the results of a study that found an increased risk of meningioma 7 to 20 times higher when a patient is on CPA. The primary objective of this study was to determine the prevalence of CPA exposure in patients who had one or more intracranial meningiomas treated surgically or with radiation therapy. The secondary objectives were to establish a description of the patients who had intracranial meningioma in Nantes and to establish whether there was a difference in the intrinsic and tumoral characteristics of patients exposed to CPA compared with patients who had no hormonal exposure and patients who had been exposed to other hormones. Methods Monocentric, retrospective study including all patients treated by surgery or radiotherapy for intracranial meningioma from 2014 to 2017 excluding those with a history of exposure to ionizing radiation or neurofibromatosis type 2. Results 388 patients were included, 277 were treated by surgery and 111 by radiotherapy. 3.9% of the patients had a history or current use of CPA, 16.2% were taking other hormonal treatment. Compared with the group without hormonal exposure, the CPA-exposed group had significantly an earlier onset of meningiomas at 48.9 vs. 61.9 years (p = 0.0005) and had more multiple meningiomas, 26.7% vs. 6.1% (p = 0.0115). Conclusions In our study, patients with a history or current use of CPA had significantly more meningiomas and were significantly younger at the onset

Interest of Repetitive Transcranial Magnetic Stimulation of the Motor Cortex in the Management of Refractory Cancer Pain in Palliative Care: Two Case Reports

International audienceBACKGROUND: Non-drug treatments should be systematically associated to the medical analgesic treatment during the terminal phase of cancer. CASES PRESENTATION: Patient 1, a 23-year-old woman, presented an adenocarcinoma of the rectum, with liver and lung metastases. Pain was initially treated by oral morphine and a combination of pregabalin and amitriptyline. Ketamine and intrathecal administration of morphine were both ineffective. Patient 2, a 69-year-old woman, presented a cutaneous T-cell lymphoma. She was admitted to the palliative care unit with mixed pain related to cutaneous lymphomatous infiltration. World Health Organization (WHO) step 3 analgesics had not been tolerated. CASES MANAGEMENT: Both patients received five consecutive 20-min sessions of repetitive transcranial magnetic stimulation to the right motor cortex. CASES OUTCOME: Patient 1 experienced a marked improvement of her pain over the days following the first repetitive transcranial magnetic stimulation session. Medical treatment was able to be rapidly decreased by about 50%, which restored an almost normal level of consciousness and lucidity. Patient 2's pain was also markedly decreased over the days following these five consecutive sessions, and repetitive transcranial magnetic stimulation also appeared to have had a beneficial effect on the patient's anxiety and mood. CONCLUSION: In the context of palliative care of cancer patients experiencing refractory pain that is difficult to control by the usual treatments, motor cortex repetitive transcranial magnetic stimulation, due to its noninvasive nature, can be used as an adjuvant therapy to improve various components of pain, including the emotional components. By reducing the doses of analgesics, repetitive transcranial magnetic stimulation decreases the severity of their adverse effects and improves the patient's quality of life