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Biomedical subjects

Philippe Michel

Publications and source records attributed to Philippe Michel.

At least 19 recordsLinked to original sources

Seletracetam (UCB 44212).

Better pharmacotherapies for epilepsy are needed for patients who are refractory to or have tolerability difficulties with current treatments. Seletracetam, a new drug in epilepsy development, is a pyrrolidone derivative structurally related to levetiracetam (trade name Keppra). It was discovered because of its high binding affinity to the synaptic vesicle 2A (SV2A) protein, which is now known to be the binding site for this family of compounds. Seletracetam shows very potent seizure suppression in models of acquired or genetic epilepsy, as well as high CNS tolerability in various animal models. Pharmacokinetic studies in animals suggest that seletracetam is rapidly and highly absorbed, with linear and time-independent pharmacokinetics. Seletracetam appears neither to inhibit nor to induce the major human drug metabolizing enzymes, and it demonstrates low plasma protein binding (<10%), which suggests a low potential for drug-drug interactions. Initial studies in humans demonstrated first-order monocompartmental kinetics with a half-life of 8 h and an oral bioavailability of >90%. Studies in healthy volunteers showed that the treatment emergent adverse events were of mild to moderate severity, were mostly of CNS origin and were resolved within 24 h. Altogether, these results suggest that seletracetam represents a promising new antiepileptic drug candidate, one that demonstrates a potent, broad spectrum of seizure protection and a high CNS tolerability in animal models, with initial clinical findings suggestive of straightforward pharmacokinetics and good tolerability.

Animals↗

Identification of brain cell death associated proteins in human post-mortem cerebrospinal fluid.

Following any form of brain insult, proteins are released from damaged tissues into the cerebrospinal fluid (CSF). This body fluid is therefore an ideal sample to use in the search for biomarkers of neurodegenerative disorders and brain damage. In this study, we used human post-mortem CSF as a model of massive brain injury and cell death for the identification of such protein markers. Pooled post-mortem CSF samples were analyzed using a protocol that combined immunoaffinity depletion of abundant CSF proteins, off-gel electrophoresis, SDS-PAGE and protein identification by LC-MS/MS. A total of 299 proteins were identified, of which 172 proteins were not previously described to be present in CSF. Of these 172 proteins, more than 75% have been described as intracellular proteins suggesting that they were released from damaged cells. Immunoblots of a number of proteins were performed on individual post-mortem CSF samples and confirmed elevated concentrations in post-mortem CSF compared to ante-mortem CSF. Interestingly, among the proteins specifically identified in the post-mortem CSF, several have been previously described as biochemical markers of brain damage.

Biomarkers↗

Cost-minimization analysis of a wide-area teleradiology network in a French region.

OBJECTIVE: The objective of our study was to perform a cost-minimization analysis of a wide-area teleradiology network. DESIGN: A prospective analysis of all transmissions over 1 year (data transmitted at the time of the remote consultation, and health outcomes of patients from medical record). INTERVENTION: The inter-hospital teleradiology network of the Aquitaine area (RIHRA) is a telemedicine system enabling the management of remote emergencies and elective radiology consultations. MAIN OUTCOME MEASURE: A cost-minimization study enabled a comparison of care procedures following the use of the network with those which would have been implemented without the network. The outcome measures of effectiveness were the transfers, hospitalizations, and consultations avoided or added. Fixed and variable costs were estimated. RESULTS: Among the 664 transmissions included in the study, 562 (85%) were performed in emergency and 102 (15%) for elective (non-emergency) cases. In emergency, 48% of transfers were avoided. For elective teleconsultations, a transfer was avoided for 37% of the patients and hospitalization for 12%. An extra consultation occurred after remote consultation for 2% of the patients. Annual saving can be estimated at 102,779 EUR for the Aquitaine area. CONCLUSIONS: This study underlines the efficiency of an inter-hospital teleradiology network. A qualitative evaluation of the impact of the use of the system should be carried out to improve technical and organizational operations.

Cost Control↗

Evaluation of the benefits for the patient arising from an inter-hospital teleradiology network in a French administrative area.

We conducted a prospective study of the teleradiology network which connects 15 hospitals in the Aquitaine area. All transmissions sent over a one-year period were examined (data transmitted at the time of the remote consultation and health outcomes of patients from their medical records). For emergency cases, the main outcome measure of effectiveness was the proportion of avoided transfers. For non-emergency cases, the main outcome measure of effectiveness was the proportion of transfers, hospitalizations and consultations avoided. There were 737 transmissions, of which 664 (90%) met the inclusion criteria. Of these, 562 (85%) were for emergency care and 102 (15%) for non-emergency care. In emergency care, the pathologies most often associated with a remote consultation were cerebral pathologies (88%) and traumatic spinal pathologies (8%); the proportion of avoided transfers was 48%. In non-emergency care, the specialties most often concerned with remote consultations were neurology/neurosurgery (36%), cardiology and pulmonary diseases (17%) and gastroenterology (14%). Transfer was avoided for 37% of the patients and hospitalization for 12%. An additional consultation occurred after remote consultation for 2% of the patients. The results confirm the effectiveness of an inter-hospital teleradiology network.

Adolescent↗

[Chyloperitoneum complicated by intestinal occlusion].

INTRODUCTION: Acute chylous ascites is an affection rarely encountered among acute painful abdominal syndromes. OBSERVATION: An acute chylous ascites was observed in a 76 Year-old man without prior history. Its etiology was an acute pancreatitis. Intestinal occlusion on the 15th day post-surgery required adhesiolysis. DISCUSSION: Intestinal occlusion is exceptional after chylous acsites despite the potential adherence of the chyle. Regarding the pathogenesis, analysis of the literature and our case report suggest either a bridle, adherences, or a peri-intestinal sheath due to the organisation of the chyle at the origin of the occlusion following chyloperitonitis. CONCLUSION: Although an etiology of chylous ascites can be an intestinal occlusion, it can, although rarely, also be a more or less late complication.

Acute Disease↗

Discovery of 4-substituted pyrrolidone butanamides as new agents with significant antiepileptic activity.

(S)-alpha-ethyl-2-oxopyrrolidine acetamide 2 (levetiracetam, Keppra, UCB S.A.), a structural analogue of piracetam, has recently been approved as an add-on treatment of refractory partial onset seizures in adults. This drug appears to combine significant efficacy and high tolerability due to a unique mechanism of action. The latter relates to a brain-specific binding site for 2 (LBS for levetiracetam binding site) that probably plays a major role in its antiepileptic properties. Using this novel molecular target, we initiated a drug-discovery program searching for ligands with significant affinity to LBS with the aim to characterize their therapeutic potential in epilepsy and other central nervous system diseases. We systematically investigated the various positions of the pyrrolidone acetamide scaffold. We found that (i) the carboxamide moiety on 2 is essential for affinity; (ii) among 100 different side chains, the preferred substitution alpha to the carboxamide is an ethyl group with the (S)-configuration; (iii) the 2-oxopyrrolidine ring is preferred over piperidine analogues or acyclic compounds; (iv) substitution of positions 3 or 5 of the lactam ring decreases the LBS affinity; and (v) 4-substitution of the lactam ring by small hydrophobic groups improves the in vitro and in vivo potency. Six interesting candidates substituted in the 4-position have been shown to be more potent antiseizure agents in vivo than 2. Further pharmacological studies from our group led to the selection of (2S)-2-[(4R)-2-oxo-4-propylpyrrolidin-1-yl]butanamide 83alpha (ucb 34714) as the most interesting candidate. It is approximately 10 times more potent than 2 as an antiseizure agent in audiogenic seizure-prone mice. A clinical phase I program has been successfully concluded and 83alpha will commence several phase II trials during 2003.

Acoustic Stimulation↗

Comparison of three methods for estimating rates of adverse events and rates of preventable adverse events in acute care hospitals.

OBJECTIVES: To compare the effectiveness, reliability, and acceptability of estimating rates of adverse events and rates of preventable adverse events using three methods: cross sectional (data gathered in one day), prospective (data gathered during hospital stay), and retrospective (review of medical records). DESIGN: Independent assessment of three methods applied to one sample. SETTING: 37 wards in seven hospitals (three public, four private) in southwestern France. PARTICIPANTS: 778 patients: medical (n = 278), surgical (n = 263), and obstetric (n = 237). MAIN OUTCOME MEASURES: The main outcome measures were the proportion of cases (patients with at least one adverse event) identified by each method compared with a reference list of cases confirmed by ward staff and the proportion of preventable cases (patients with at least one preventable adverse event). Secondary outcome measures were inter-rater reliability of screening and identification, perceived workload, and face validity of results. RESULTS: The prospective and retrospective methods identified similar numbers of medical and surgical cases (70% and 66% of the total, respectively) but the prospective method identified more preventable cases (64% and 40%, respectively), had good reliability for identification (kappa = 0.83), represented an acceptable workload, and had higher face validity. The cross sectional method showed a large number of false positives and identified none of the most serious adverse events. None of the methods was appropriate for obstetrics. CONCLUSION: The prospective method of data collection may be more appropriate for epidemiological studies that aim to convince clinical teams that their errors contribute significantly to adverse events, to study organisational and human factors, and to assess the impact of risk reduction programmes.

Chi-Square Distribution↗

Binding characteristics of [3H]ucb 30889 to levetiracetam binding sites in rat brain.

Levetiracetam (2S-(2-oxo-1-pyrrolidinyl)butanamide, KEPPRA, a novel antiepileptic drug, has been shown to bind to a specific binding site located in brain (levetiracetam binding site [Eur. J. Pharmacol. 286 (1995) 137]). However, [3H]levetiracetam displayed only micromolar affinity for these sites making it an unsuitable probe for further characterization. The present study describes the binding properties of an analogue of levetiracetam: [3H]ucb 30889, (2S)-2-[4-(3-azidophenyl)-2-oxopyrrolidin-1-yl]butanamide. [3H]ucb 30889 binds reversibly to specific binding sites in rat brain. Kinetics at 4 degrees C were biphasic with half-times of association and dissociation of, respectively, 3 and 4 min for the fast component and 47 and 61 min for the slow component. [3H]ucb 30889 saturation binding curves were compatible with the labelling of a homogenous population of binding sites having a B(max) of 4496+/-790 fmol/mg protein (mean+/-S.D., n=5) and a K(d) of 62+/-20 nM (mean+/-S.D., n=5), a 20-fold increase in affinity compared to [3H]levetiracetam. Competition binding curves with ligands known to interact with levetiracetam binding sites and tissue distribution restricted to the brain indicated that [3H]ucb 30889 and [3H]levetiracetam bind to the same site. Although levetiracetam binding sites and GABA(A) (gamma-aminobutyric acid) receptors share some ligands such as pentobarbital and pentylenetetrazol, experiments performed with [35S]TBPS (tert-butyl-bicyclo[2.2.2]phosporothionate), a probe for the GABA(A) Cl(-) channel do not support the hypothesis that levetiracetam binding sites are part of the GABA(A) receptor complex. Preliminary autoradiography studies in rat brain revealed that [3H]ucb 30889 labels specific sites in all brain regions and that this binding is concentration-dependently displaced by levetiracetam.

Animals↗

Localization and photoaffinity labelling of the levetiracetam binding site in rat brain and certain cell lines.

Levetiracetam (2S-(2-oxo-1-pyrrolidinyl)butanamide, KEPPRA, a novel antiepileptic drug, has been shown to bind to a specific binding site located in the brain (Eur. J. Pharmacol. 286 (1995) 137). To identify the protein constituent of the levetiracetam binding site in situ, we synthesized the photoaffinity label [3H]ucb 30889 ((2S)-2-[4-(3-azidophenyl)-2-oxopyrrolidin-1-yl]butanamide), a levetiracetam analog with higher affinity for the levetiracetam binding site. This radioligand was used to map the levetiracetam binding site within the brain and to study its cellular and subcellular distribution. Autoradiography experiments using [3H]ucb 30889 in rat brain revealed a unique distribution profile that did not match that of classical receptors known to be involved in the generation of epileptic seizures. There was a high level of binding in the dentate gyrus, the superior colliculus, several thalamic nuclei, the molecular layer of the cerebellum and to a lesser extent in the cerebral cortex, the striatum and the hypothalamus. The levetiracetam binding site was restricted to neuronal cell types, undifferentiated PC12 cells and was highly enriched in synaptic vesicles. [3H]ucb 30889 was also used in photoaffinity labelling studies and shown to bind covalently to a membrane protein with a molecular weight of approximately 90 kDa.

Animals↗

[Assessment of pain in elderly hospitalised patients. A transversal descriptive survey].

INTRODUCTION: The assessment and treatment of pain in elderly hospitalised patients are essential elements for the management of these patients. Within the context of a policy aimed at fighting against pain, a transversal survey was conducted at the university hospital centre in Bordeaux to enhance knowledge on pain, its impact and the difficulties in its assessment in these elderly patients. OBJECTIVE: Analyse the data of this survey concerning patients aged 65 and over, hospitalised in various departments of medicine and in the Geriatric centre. METHODS: In this "on a given day" transversal survey, 221 patients underwent self-assessment of their pain using a questionnaire and the numerical scale. 365 patients with cognitive or phasic disorders were assessed using a behavioural scale (Doloplus). The prevalence of pain was calculated in the various departments. The type of pain, its impact, its acknowledgment by the nurses and the physicians and the treatments were described. RESULTS: The prevalence of pain was of 47.5% in the patients who underwent self-assessment. In the patients who underwent a hetero-assessment, it was of 63.6% in Medicine and 20% in the Geriatric centre. Acute pain predominated in medicine (49%) and chronic pain in the Geriatric centre (52%). The impact of pain on morale was moderate or severe in 60% of patients, and on sleep in 51%. The simultaneous agreement of the nurses and physicians on the pain felt by the patients was of 32% in Medicine and 44.5% in the Geriatric centre. CONCLUSION: There is a problem in the acknowledgment of pain in elderly patients. This is related to the systematic non-use of assessment tools and the overlooking of rules for the use of analgesics, particularly in the treatment of chronic pain.

Aged↗

Logistic or additive EuroSCORE for high-risk patients?

OBJECTIVES: To assess whether the use of the full logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE) is superior to the standard additive EuroSCORE in predicting mortality in high-risk cardiac surgical patients. METHODS: Both the simple additive EuroSCORE and the full logistic EuroSCORE were applied to 14,799 cardiac surgical patients from across Europe, of whom there were 4293 high-risk patients (additive EuroSCORE of 6 or more). The systems were compared for absolute prediction and discrimination (area under the receiver operating characteristic (ROC) curve). RESULTS: Actual mortality was 4.72%. The logistic model was closer to this than the additive model (4.84% (4.72-4.94) versus 4.21 (4.21-4.26)). Most of this difference was due to high-risk patients where actual mortality was 11.18% and predicted was 7.83% (additive) and 11.23% (logistic). Discrimination was similar in both systems as measured by the area under the ROC curve (additive 0.783, logistic 0.785). CONCLUSIONS: The additive EuroSCORE model remains a simple "gold standard" for risk assessment in European cardiac surgery, usable at the bedside without complex calculations or information technology. The logistic model is a better risk predictor especially in high-risk patients and may be of interest to institutions engaged in the study and development of risk stratification.

Aged↗

Results of the first 100 accreditation procedures in France.

PURPOSE: To identify the areas of needed improvement that were most frequently identified in the first 100 accredited hospitals by the French Accreditation College (FAC) according to the standards manual. To compare the outcomes of accreditation procedures according to the status and size of the accredited hospitals. DATA SOURCES: We analyzed the first 100 summaries of accreditation reports available on the website of the Agence Nationale d'Accréditation et d'Evaluation en Santé (ANAES). DATA EXTRACTION: Data were collected on hospitals, accreditation processes, and outcomes (decisions of the FAC). For each decision, we assessed the relationship with accreditation manual criteria, and analyzed their distribution by chapter. RESULTS: of data synthesis. Among the 100 accredited hospitals (40 public, 43 private, 17 mixed), nine were accredited without recommendations for improvement, 47 with recommendations, 40 with reservations, and four with major reservations. All of them received requests for improvement. No significant difference was found concerning the FAC decisions according to status and size of hospitals, although there was a trend that the larger the hospital, the more numerous and more serious the decisions of the FAC. The main topics addressed by decisions were those given high priority by the FAC (information given to patients and its traceability on patient records, and signing of prescriptions for medication). CONCLUSION: Despite wide heterogeneity in the summaries on accreditation and in FAC decision-making, this study provides an initial insight into common quality defects and ANAES priorities for hospitals in France.

Accreditation↗

A multicenter cluster randomized controlled trial of strategies to improve thyroid function testing.

OBJECTIVES: This project aimed to compare the independent and combined effectiveness of two implementation interventions of guidelines for ordering thyroid function tests: a Memorandum Pocket Card (MPC) and a Test Request Form (TRF). RESEARCH DESIGN: Intervention groups were wards. The study used an experimental 2*2 factorial design with matching hospitals according to size and activity and wards according to preintervention appropriateness for test ordering. Four ward groups were established: the dual intervention group, the order form group, the pocket card group and the control group. Physicians in all groups received guidelines and were invited to a local information meeting. MEASURES: The main outcome measure of effectiveness was the Guideline Conformity Rate (GCR). RESULTS: Six hospitals participated in the study (two middle-sized hospitals, two small-sized hospitals and two psychiatric hospitals). A total of 1412 orders for thyroid function tests were collected. GCR was 78% in the dual intervention group, 83% in the order form group, 73% in the pocket card group and 62% in the control group. The interaction between TRF and MPC was not significant (beta = -0.70; P = 0.21). Compared with simple information, TRF was effective in increasing GCR (OR, 2.65; 95% CI, 1.52-4.62), unlike MPC (OR, 1.28; CI, 0.75-2.19). CONCLUSIONS: Using a robust design, our study shows the greater effectiveness of TRF than MPC and their association in implementing thyroid function test guidelines.

Adult↗

Regional differences in surgical heart valve disease in Europe: comparison between northern and southern subsets of the EuroSCORE database.

BACKGROUND AND AIMS OF THE STUDY: Although rates for coronary and valve surgery vary between northern and southern Europe, differences in the features of valve disease leading to surgery in Europe are poorly documented. The study aim was to compare demographics, risk factors, procedures and outcome in valve surgery between European regions, using the EuroSCORE database. METHODS: Between September and December 1995, information on 98 variables (risk factors, procedures and outcome) were collected on valve surgery patients in 128 European centers. Patients were allocated to two geographic subgroups (north, n = 1,990; south, n = 3,682). The distribution of variables was assessed. Subsequently, the impact of preoperative and operative risk factors on mortality was analyzed in both groups using a bivariate analysis. Risk-adjusted outcomes were then compared according to the EuroSCORE. RESULTS: Significant differences were identified for clinical features, risk factors and procedures. In northern Europe, surgery was performed on older patients with more severe coronary or associated disease, whilst in the south the cardiac status seemed more severely compromised. Degenerative aortic disease prevailed in the north (aortic valve replacement in 72.7% of cases), whilst in the south mitral surgery accounted for 46.1% of procedures. Despite differences in crude mortality (6.9% north versus 5.7% south), outcomes (when adjusted to risks) seemed comparable (observed-to-expected mortality ratio 0.90 for north versus 0.84 for south). The impact of individual risk factors on mortality was similar, except for atrial fibrillation. CONCLUSION: Despite large epidemiological differences between northern and southern Europe in terms of valve surgery, performances and outcomes were similar when individual risk factors and overall risk profiles were taken into account.

Aged↗

Plasma etched polymer microelectrochemical systems.

This paper presents a novel technique based on plasma etching for the mass production of polymer microchip devices. The method consists of the patterning of a photo-resist by a high resolution printer on a foil composed of three layers (5 microm copper/50 microm polyimide/5 microm copper). After this step, both copper layers are chemically etched in order to serve as a contact mask on the polyimide surface so as to produce the desired microstructure pattern. The foil is placed into a reactive plasma chamber in order to etch the exposed polyimide by means of an oxidizing plasma. The method enables holes, lines or larger areas to be etched, thereby generating either microholes, microchannels or electrodes in the plastic material. The copper can then be chemically removed or further patterned to produce conductive pads which are further electroplated with gold. The microchannel is then covered with a polyethylene terephthalate/polyethylene (PET/PE) lamination. The strength of this technology is that access holes for the fluid inlet and outlet, as well as gold coated electrodes can be fabricated without post-processing in a batch process. Demonstration of the application of such microelectrochemical systems is shown here by voltammetric detection inside a 60 nL microchannel, which presents the special feature of linear depletion of the analytes in the direction parallel to the microchannel.

Journal Article↗