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M Bussière

Publications and source records attributed to M Bussière.

16 recordsLinked to original sources
PubMed2006

Evaluating a formal evidence-based clinical practice curriculum in a neurology residency program.

BACKGROUND: Since 1998, the University of Western Ontario Evidence-Based Neurology Programme has been fostering life-long self-teaching, self-evaluation, and promoting improvement of the care of neurological patients by teaching neurology residents to practice Evidence-Based Clinical Practice (EBCP). DESIGN/METHODS: Using a questionnaire/survey we evaluated participation during EBCP sessions and the applicability of EBCP to current and future clinical practice. Also, using a rating scale we investigated how likely our residents' and graduates' clinical practice has been influenced by the EBCP knowledge; and, if they were teaching these concepts to residents or medical students. The questionnaire was sent to all neurology residents and neurologists that graduated after implementation of the programme. RESULTS: All residents (100%) returned the survey/questionnaire, indicating that they attended the sessions consistently. Even though all respondents believed that the EBCP concepts were useful during their training, the concepts were infrequently utilized because of time constraints. On a scale of 1 to 10, they rated the influence to include EBCP concepts in their daily clinical practice as high (average: 6.8, S.D. 1.5). They all had frequent contact with medical students and non-neurology residents, but did not teach EBCP concepts to them on a consistent basis, because of time limitations. 10 (77%) out of 13 graduates returned the survey/questionnaire. They also believed the EBCP concepts were useful, but only used them when time allowed. They also rated the influence to include EBCP concepts in their daily clinical practice as high (mean 8.5, S.D. 1.2). Most graduates had frequent contact with trainees, but did not teach EBCP concepts to them on a consistent basis because of time constraints. Finally, all expressed the need to continue having this formal curriculum during residency. CONCLUSION/RELEVANCE: Although EBCP incorporated into the curriculum of a neurology residency programme increased neurologists and neurology trainees' confidence in knowledge of existing evidence, and reinforced the EBCP principles, these concepts were not used in daily clinical practice and were not taught to more junior trainees due to time constraints.

Academic Medical Centers↗
PubMed2001

Compartmentalization of choline and acetylcholine metabolism in cultured sympathetic neurons.

To determine the relative contribution of cell bodies and distal axons to the production of acetylcholine, we used retinoic acid to induce a cholinergic phenotype in compartmented cultures of rat sympathetic neurons. When [3H]choline was given to cell bodies/proximal axons for 24 h, 98% of the radiolabel was recovered as choline, phosphocholine, CDP-choline and phosphatidylcholine, whereas only 1 to 2% of the radiolabel was incorporated into acetylcholine. Choline taken up by cell bodies and transported to axons is poorly utilized for acetylcholine biosynthesis. In contrast, when distal axons were supplied with [3H]choline, 11% of the radiolabel was recovered in acetylcholine after 24 h, the remainder being incorporated into precursors/metabolites of phosphatidylcholine. The lack of acetylcholine synthesis in cell bodies/proximal axons could not be ascribed to an absence of choline acetyltransferase activity in this region of the neurons, since the specific activity of this enzyme was similar in cell bodies/proximal axons and distal axons. The rate of choline uptake by distal axons (15.3 4.4 nmol/5 min/mg protein) was approximately 10-fold greater than by cell bodies/proximal axons (1.6 0.8 nmol/5 min/mg protein). Moreover, choline uptake into distal axons was inhibited by 74.5% by hemicholinium-3, and by 80.1% by removal of Na(+) from the medium. In contrast, choline uptake by cell bodies/proximal axons was not significantly inhibited by hemicholinium-3 or Na(+) removal. These results suggest that the majority of axonal acetylcholine is synthesized in distal axons/axon terminals from choline taken up by a high-affinity choline transporter in distal axons.

Acetylcholine↗
PubMed1999

Inhibition of phosphatidylcholine and phosphatidylethanolamine biosynthesis in rat-2 fibroblasts by cell-permeable ceramides.

Phospholipids and sphingolipids are important precursors of lipid-derived second messengers such as diacylglycerol and ceramide, which participate in several signal transduction pathways and in that way mediate the effects of various agonists. The cross-talk between glycerophospholipid and sphingolipid metabolism was investigated by examining the effects of cell-permeable ceramides on phosphatidylcholine (PtdCho) and phosphatidylethanolamine (PtdEtn) synthesis in Rat-2 fibroblasts. Addition of short-chain C6-ceramide to the cells resulted in a dose- and time-dependent inhibition of the CDP-pathways for PtdCho and PtdEtn synthesis. Treatment of cells for 4 h with 50 microM C6-ceramide caused an 83% and a 56% decrease in incorporation of radiolabelled choline and ethanolamine into PtdCho and PtdEtn, respectively. Exposure of the cells for longer time-periods (>/= 16 h) to 50 microM C6-ceramide resulted in apoptosis. The structural analogue dihydro-C6-ceramide did not affect PtdCho and PtdEtn synthesis. In pulse-chase experiments, radioactive choline and ethanolamine accumulated in CDP-choline and CDP-ethanolamine under the influence of C6-ceramide, suggesting that synthesis of both PtdCho and PtdEtn were inhibited at the final step in the CDP-pathways. Indeed, cholinephosphotransferase and ethanolaminephosphotransferase activities in membrane fractions from C6-ceramide-treated cells were reduced by 64% and 43%, respectively, when compared with control cells. No changes in diacylglycerol mass levels or synthesis of diacylglycerol from radiolabelled palmitate were observed. It was concluded that C6-ceramide affected glycerophospholipid synthesis predominantly by inhibition of the step in the CDP-pathways catalysed by cholinephosphotransferase and ethanolaminephosphotransferase.

Animals↗
PubMed1999

Accelerated fractionated proton/photon irradiation to 90 cobalt gray equivalent for glioblastoma multiforme: results of a phase II prospective trial.

OBJECT: After conventional doses of 55 to 65 Gy of fractionated irradiation, glioblastoma multiforme (GBM) usually recurs at its original location. This institutional phase II study was designed to assess whether dose escalation to 90 cobalt gray equivalent (CGE) with conformal protons and photons in accelerated fractionation would improve local tumor control and patient survival. METHODS: Twenty-three patients were enrolled in this study. Eligibility criteria included age between 18 and 70 years, Karnofsky Performance Scale score of greater than or equal to 70, residual tumor volume of less than 60 ml, and a supratentorial, unilateral tumor. Actuarial survival rates at 2 and 3 years were 34% and 18%, respectively. The median survival time was 20 months, with four patients alive 22 to 60 months postdiagnosis. Analysis by Radiation Therapy Oncology Group prognostic criteria or Medical Research Council indices showed a 5- to 11-month increase in median survival time over those of comparable conventionally treated patients. All patients developed new areas of gadolinium enhancement during the follow-up period. Histological examination of tissues obtained at biopsy, resection, or autopsy was conducted in 15 of 23 patients. Radiation necrosis only was demonstrated in seven patients, and their survival was significantly longer than that of patients with recurrent tumor (p = 0.01). Tumor regrowth occurred most commonly in areas that received doses of 60 to 70 CGE or less; recurrent tumor was found in only one case in the 90-CGE volume. CONCLUSIONS: A dose of 90 CGE in accelerated fractionation prevented central recurrence in almost all cases. The median survival time was extended to 20 months, likely as a result of central control. Tumors will usually recur in areas immediately peripheral to this 90-CGE volume, but attempts to extend local control by enlarging the central volume are likely to be limited by difficulties with radiation necrosis.

Actuarial Analysis↗
PubMed1997

Elevation of ceramide within distal neurites inhibits neurite growth in cultured rat sympathetic neurons.

Sphingolipids are abundant constituents of neuronal membranes and have been implicated in intracellular signaling. We show that two analogs of glycosphingolipid biosynthetic intermediates, fumonisin B1 (which inhibits dihydroceramide synthesis) and DL-1-phenyl-2-palmitoylamino-3-morpholino-1-propanol (PPMP) (which inhibits glucosylceramide synthesis) decrease glycosphingolipid synthesis in rat sympathetic neurons. Although both fumonisin and PPMP inhibit glycosphingolipid synthesis, these inhibitors have differential effects on ceramide metabolism in axons. threo-PPMP, but not erythro-PPMP or fumonisin, induces an accumulation of [3H]palmitate-labeled ceramide and impairs axonal growth. Moreover, exogenously added, cell-permeable C6-ceramide, but not C6-dihydroceramide, mimicks the effect of PPMP. Our studies suggest that the lipid second messenger ceramide acts in distal axons, but not cell bodies, as a negative regulator of neurite growth.

Animals↗
PubMed1996

Analysis of prostate and seminal vesicle motion: implications for treatment planning.

PURPOSE: To quantify prostate and seminal vesicle positional changes (target motion) between treatment planning and delivery, and to identify the factors contributing to target motion. METHODS AND MATERIALS: Thirty patients with adenocarcinoma of the prostate were prospectively evaluated by analyzing two sequential planning computerized tomography (CT) scans (S1, obtained prior to treatment, and S2, obtained during the fourth week of treatment) for each patient. All anatomical volumes of interest (soft tissue and bony) were reconstructed from transverse CT images and projected onto anterior and lateral beam's-eye view projections. Positional changes between S1 and S2 were eliminated by applying a rigid body translation and rotation. Target motion was then measured by recording the positional change between S1 and S2 at the edges (right, left, superior, inferior). Potential correlation of target motion with bladder volume, rectal volume, and rectal diameter changes were evaluated by linear regression analysis. RESULTS: Neither the prostate nor seminal vesicles remained fixed with respect to bony anatomy between S1 and S2. The distribution of positional changes were generally small (< 0.5 cm), but maximum displacements of 1.5-2.2 cm did occur, particularly in the lateral view. In this study, bladder volume changes between the scans were small and did not correlate with target motion (P = 0.67). Both rectal volume and rectal diameter changes correlated with target motion for both the prostate (p = 0.004 and 0.005, respectively) and seminal vesicles (p < 0.001 and < 0.001, respectively). However, neither the initial rectal volume nor the initial rectal diameter could be used to predict subsequent target motion when evaluated either singly or as part of a multiple regression model. CONCLUSIONS: Target motion occurs during the course of treatment planning and delivery and should be considered when designing conformal radiation fields. Although the target position at the time of planning CT may differ substantially from the mean treatment position, target motion cannot be predicted by evaluating simply measured parameters from a single scan, or double scan sequence.

Adenocarcinoma↗
PubMed1996

CTP: phosphocholine cytidylyltransferase is both a nuclear and cytoplasmic protein in primary hepatocytes.

CTP:phosphocholine cytidylyltransferase (CT) has recently been reported to be a predominantly intranuclear enzyme in several cell lines (Wang et al., J. Biol. Chem. 268, 5899-5904 (1993)). This contrasts with previous reports that CT was a cytosolic protein that translocated to the endoplasmic reticulum upon activation. The aim of the present study was to compare the localization of CT in CHO cells and in primary rat hepatocytes. Indirect immunofluorescence of CHO cells revealed a largely nuclear localization of the CT. On the other hand, immunogold electron microscopy and biochemical studies showed a similar density of distribution of CT between the nucleus and cytoplasm. In primary rat hepatocytes immunofluorescence studies indicated that CT was largely cytoplasmic. Studies by immunogold electron microscopy of rat hepatocytes demonstrated that the enzyme was homogeneously distributed throughout all cytoplasmic regions and the nucleoplasm. This result was confirmed by biochemical studies using digitonin and streptolysin O, which permeabilizes the plasma membrane of cells. Enucleation studies indicated that in CHO cells 76% of the CT activity was in the nuclear fraction, whereas in hepatocytes only 32% was recovered in this fraction. The data indicate that CT is found both in nuclear and cytoplasmic fractions of primary hepatocytes and is not predominantly a nuclear enzyme.

Animals↗
PubMed1995

Reciprocal regulation of choline acetyltransferase and choline kinase in sympathetic neurons during cholinergic differentiation.

The regulation of the synthesis of acetylcholine and phosphatidylcholine in rat sympathetic neurons was examined in the context of cholinergic differentiation. We demonstrate that the activities of choline acetyltransferase (ChAT) and choline kinase (CK) are inversely affected by treatment of sympathetic neurons with retinoic acid, utilized as an agent that induces cholinergic differentiation. Whereas ChAT specific activity increased 2- to 4-fold after 12 days of treatment with 5 microM retinoic acid, CK specific activity decreased by 25-30%. These changes in enzyme activities were essentially reflected in the incorporation of [methyl-3H]choline into ACh and the metabolites of the CDP-choline pathway for phosphatidylcholine synthesis. When sympathetic neurons were treated under high potassium conditions (50 mM) for 12 days, the specific activity of CK increased 1.3-fold whereas the activity of ChAT decreased by up to 90%. Furthermore, experiments in which the incorporation of [methyl-3H]choline into ACh and the metabolites of the CDP-choline pathway was measured in the absence of Na+ or in the presence of hemicholinium-3 (HC-3), demonstrate that CK has access to the same pool of choline utilized by ChAT. These results provide evidence that the activities of ChAT and CK may be inversely regulated during the process of cholinergic differentiation.

Acetylcholine↗
PubMed1994

Evidence that the major membrane lipids, except cholesterol, are made in axons of cultured rat sympathetic neurons.

Membrane lipids and proteins required for axonal growth and regeneration are generally believed to be synthesized in the cell bodies of neurons and transported into the axons. However, we have demonstrated recently that, in cultured rat sympathetic neurons, axons themselves have the capacity to synthesize phosphatidylcholine, sphingomyelin, and phosphatidylethanolamine. In these experiments, we employed a compartment model of neuron culture in which pure axons grow in a fluid environment separate from that containing the cell bodies. In the present study, we again used compartmented cultures to confirm and extend the previous results. We have shown that three enzymes of phosphatidylcholine biosynthesis via the CDP-choline pathway are present in axons. We have also shown that the rate-limiting step in the biosynthesis of phosphatidylcholine by this route in neurons, and locally in axons, is catalyzed by the enzyme CTP:phosphocholine cytidylytransferase. The biosynthesis of other membrane lipids, such as phosphatidylserine, phosphatidylethanolamine derived by decarboxylation of phosphatidylserine, phosphatidylinositol, and fatty acids, also occurs in axons. However, the methylation pathway for the conversion of phosphatidylethanolamine into phosphatidylcholine appears to be a quantitatively insignificant route for phosphatidylcholine synthesis in neurons. Moreover, our data provided no evidence for the biosynthesis of another important membrane lipid, cholesterol, in axons.

Acetates↗
PubMed1993

[Double-blind study versus excipient of 0.75% metronidazole gel in the treatment of rosacea].

INTRODUCTION: The proven value of tetracyclines and metronidazole administered orally in the treatment of the chronic and recurrent disease that is rosacea is tempered by the important undesirable effects observed in long-term therapy. The purpose of this study was to test the effectiveness of an 0.75 p. 100 metronidazole gel in the treatment of rosacea. PATIENTS AND METHODS: The study involved two groups of patients: one received the metronidazole gel and the other the vehicle of the gel used as placebo. The multicentre randomized trial was conducted in the double-blind fashion by 18 private dermatologists working in the Paris region. Fifty one patients who, since more than 3 months, had been presenting with rosacea, defined as at least 4 papulopustules associated with erythema and/or telangiectasia, entered the trial. Topical treatments and systemic treatments which had shown some activity against rosacea had been interrupted for 15 days or 2 months respectively. The product (or the placebo) was applied a.m. and p.m. on the whole dry face. The patients were seen on days 0, 21 and 42. The evaluation was purely clinical, and the principal criterion of judgement was a change in the number of papulopustules between days 0 and 42. RESULTS: The metronidazole gel reduced the number of papulopustules between day 0 and day 42, and this reduction was significantly greater than that observed with the excipient alone. The active product began to be effective during the third week and remained so during the next three weeks. Both the metronidazole gel and its excipient seemed to be poorly tolerated, with frequent complaints of dry skin, but in 5 women of the metronidazole group this dryness was alleviated by application of moisturizers. CONCLUSION: This study has demonstrated that the 0.75 p. 100 metronidazole gel is effective in the treatment of the papulopustular component of rosacea.

Administration, Topical↗
PubMed1990

[A double-blind placebo-controlled study of a 2 percent foaming lotion of ketoconazole in a single application in the treatment of pityriasis versicolor].

A double-blind, placebo-controlled therapeutic trial of ketoconazole presented as a foam and applied only once was carried out on 61 patients by a group of 15 private dermatologists practising in the Paris region. All patients had tinea versicolor clinically diagnosed, then confirmed by a positive patch test, as assessed by a single mycologist. The main criterion of therapeutic effectiveness was negativation of the patch test 30 days after a single topical application of the ketoconazole foam. On day 30, the test was negative in 22 of the 28 patients in the ketoconazole group and in 5 of the 29 patients in the placebo (i.e. excipient) group (p less than 10(-5). Clinical and mycological cure was observed in only 11 of the 28 patients treated with the active substance, but among the 11 patients who still showed skin lesions despite a negative mycological examination 10 had achromic lesions which could be regarded as residual. This clearly indicates that the only criterion that can be used in a therapeutic trial on tinea versicolor is the mycological result. The active substance and the excipient were well tolerated; two patients in the ketoconazole group reported tingling of the skin at the site of application. We conclude that a single application of ketoconazole foam in effective and well tolerated in tinea versicolor. The single application technique unquestionably has advantages over repeated applications and should result in better patient's compliance and greater effectiveness in the long term.

Administration, Cutaneous↗