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Biomedical subjects

S Leclercq

Publications and source records attributed to S Leclercq.

At least 19 recordsLinked to original sources
PubMed2007

Progress in understanding processes underlying occupational accidents on the level based on case studies.

The purpose of this work was to further the knowledge of contexts surrounding accidents on the level in occupational situations with a view to proposing suitable actions for the prevention of these accidents. The study, undertaken at three establishments belonging to a national rail transport company, was based on quantitative and qualitative analysis of accident-on-the-level data available at the establishments concerned, typology of these accidents, interviews with victims and activity analysis. Understanding accidents on the level through building scenarios makes it possible to consider the relevance of prevention actions, such as workplace or environmental design/remediation and machine access system design. Moreover, it also makes it possible to consider curtailing the injury-causing aspect of the physical environment by reducing its 'aggressiveness'. Finally, the prospects emerging from this work in the research field are discussed.

Accidental Falls↗
PubMed2006

Limits on spin-independent interactions of weakly interacting massive particles with nucleons from the two-tower run of the cryogenic dark matter search.

We report new results from the Cryogenic Dark Matter Search (CDMS II) at the Soudan Underground Laboratory. Two towers, each consisting of six detectors, were operated for 74.5 live days, giving spectrum-weighted exposures of 34 (12) kg d for the Ge (Si) targets after cuts, averaged over recoil energies 10-100 keV for a weakly interacting massive particle (WIMP) mass of 60 GeV/c2. A blind analysis was conducted, incorporating improved techniques for rejecting surface events. No WIMP signal exceeding expected backgrounds was observed. When combined with our previous results from Soudan, the 90% C.L. upper limit on the spin-independent WIMP-nucleon cross section is 1.6 x 10(-43) cm2 from Ge and 3 x 10(-42) cm2 from Si, for a WIMP mass of 60 GeV/c2. The combined limit from Ge (Si) is a factor of 2.5 (10) lower than our previous results and constrains predictions of supersymmetric models.

Journal Article↗
PubMed2004

Systemic analysis of so-called 'accidents on the level' in a multi trade company.

Slips, trips and falls on the level are considered commonplace and are rarely subjected to in-depth analysis. They occur in highly varied circumstances in an occupational situation. In-depth analysis of these accidents was conducted within a company with the aim of understanding them better, to be able to discuss prevention field possibilities and priorities for the company concerned. Firstly, available data on 'accidents on the level' occurring over the last 4 years were analysed and a typology for these accidents was derived, based on individual activity at the time of the accident and accident location. The three most serious accident-causing situations were analysed in-depth from interviews with injured persons, as well as from activity observation and activity-related verbal information obtained from operatives. These most serious situations involved accidents occurring when climbing down from trucks or when walking either in surroundings outside company premises or from (to) a vehicle to (from) a work location. In-depth accident analysis and characterization of accident-causing situations as a whole enhance our understanding of the accident process and allow us to envisage priorities for action in the prevention field, in operational terms. Each accident-causing situation reveals environmental factors that in fact constitute accident factors (obstacle, stone, etc.), when the individual walks or climbs down from a truck. Analysis shows that other events are necessary for accident occurrence. For example, the individual may be subjected to a time constraint or may be preoccupied. Results obtained here, in a company integrating different trades, are discussed and compared with those referred to in the literature. Generalization of some of these results is also considered.

Accidental Falls↗
PubMed2002

Slip prevention: validation of duplicates reproducing industrial floor surface state microgeometry.

The present study falls within the scope of work on the prevention of slips occurring on industrial workplace floor surfaces. Floor microgeometry is a determining factor in anti-slip flooring. Industrial environment-based quantification of floor microgeometrical properties is more restricting than laboratory quantification. The aim of the present study was to develop a duplication technique allowing reproduction of in situ floor microgeometry so as to be able to quantify this microgeometry in the laboratory. Duplicates were produced from a sample of five industrial floors. Surface microgeometry was characterized for both industrial floors and associated duplicates in order to study their microgeometrical changes following the duplicating operation. The purpose of this process was to reach a conclusion on the "reliability" of the duplication technique, on which the use of such duplicates depends. Parameters established from digitalized surfaces reveal differences of less than 5% between duplicates and original floor and this enables us to conclude that these duplicates offer a high degree of reliability with respect to results dispersion.

Accidental Falls↗
PubMed2001

The role of friction in the measurement of slipperiness, Part 1: friction mechanisms and definition of test conditions.

Friction has been widely used as a measure of slipperiness. However, controversies around friction measurements remain. The purposes of this paper are to summarize understanding about friction measurement related to slipperiness assessment of shoe and floor interface and to define test conditions based on biomechanical observations. In addition, friction mechanisms at shoe and floor interface on dry, liquid and solid contaminated, and on icy surfaces are discussed. It is concluded that static friction measurement, by the traditional use of a drag-type device, is only suitable for dry and clean surfaces, and dynamic and transition friction methods are needed to properly estimate the potential risk on contaminated surfaces. Furthermore, at least some of the conditions at the shoe/floor interface during actual slip accidents should be replicated as test conditions for friction measurements, such as sliding speed, contact pressure and normal force build-up rate.

Accidental Falls↗
PubMed2001

The role of friction in the measurement of slipperiness, Part 2: survey of friction measurement devices.

This paper seeks to address questions related to friction measurement such as how friction is related to human-centred assessment and actual slipping, and how repeatable friction measurements are. Commonly used devices for slipperiness measurement are surveyed and their characteristics compared with suggested test conditions from biomechanical observations summarized in Part 1. The issues of device validity, repeatability, reproducibility and usability are examined from the published literature. Friction assessment using the mechanical measurement devices described appears generally valid and reliable. However, the validity of most devices could be improved by bringing them within the range of human slipping conditions observed in biomechanical studies. Future studies should clearly describe the performance limitations of any device and its results and should consider whether the device conditions reflect these actual human slipping conditions. There is also a need for validation studies of more devices by walking experiments.

Accidental Falls↗
PubMed2001

Absolute configuration of anabasine from Messor and Aphaenogaster ants.

A method has been developed to assign the absolute configuration and enantiomeric excess of anabasine based on small amounts of material (in the microgram range), by derivatization with (+)-menthylchloroformate followed by capillary GC analysis of the resulting carbamate(s). This method was applied to three samples of anabasine isolated from Messor and Aphaenogaster ants. In Messor sanctus, only (2'S)-anabasine was present, whereas in Aphaenogaster subterranea and A. miamiana (2'S)-anabasine was determined to have an ee of 78 and 24%, respectively.

Anabasine↗
PubMed2001

Slip resistance of industrial floor surfaces: development of an elastomer suited to in-situ measurement.

Slips contribute to 12% of occupational accidents. A slip resistant floor is a mean to prevent slipping accidents occurring in workshops. Floor slip resistance is often evaluated by measuring a friction index, proportional to the force opposing slipping of a reference elastomer on the floor surface under test. When implementing a portable appliance, slip resistance measurements carried out on lubricated floors were not stabilized. The authors advanced the hypothesis of oil impregnating the elastomer. A new elastomer suited to in-situ measurement has been developed to achieve stable measuring conditions. This study highlights the fact that the nature and characteristics of a reference elastomer must be specified when slip resistance measurements are carried out.

Accidental Falls↗
PubMed2001

Clinical and radiological amelioration of refractory peripheral spondyloarthritis by pulse intravenous pamidronate therapy.

OBJECTIVE: To examine the potential therapeutic properties of an aminobisphosphonate, pamidronate, using clinical and laboratory outcome variables together with dynamic magnetic resonance imaging (MRI) and gadolinium augmentation in patients with spondyloarthropathy (SpA) refractory to nonsteroidal antiinflammatory drugs (NSAID). METHODS: We studied 9 patients (7 male, 2 female) of mean age 27.9 years (range 19-38) and mean disease duration of 5.5 years (range 0.5-20). Five had ankylosing spondylitis (AS), 3 had undifferentiated SpA, and one had reactive arthritis. Seven were HLA-B27 positive. Two had inflammatory bowel disease. Pamidronate (60 mg) was given intravenously on Days 1, 2, 14, 28, and 56, over 4 h in 500 ml of 5% dextrose. Clinical outcome assessments included the BASDAI (disease activity), BASFI (function), BASGI (global well being) composite visual analog instruments, and swollen and tender joint count. Laboratory variables included the erthrocyte sedimentation rate (ESR) and C-reactive protein (CRP). Dynamic MRI with gadolinium augmentation of synovium and bone was performed at baseline and at Day 84 in the first 6 patients enrolled in the study. RESULTS: All patients completed the study and there was a significant improvement in all clinical and laboratory variables assessed. Mean swollen and tender joint count decreased by 93.8% (p = 0.017) and 98.2% (p = 0.012), respectively, and complete clinical resolution of synovitis was noted in 5 patients. BASDAI decreased by 44.2% (p = 0.028), BASFI by 47.3% (p = 0.015), and BASGI by 42.2% (p = 0.011). ESR and CRP declined by 49.4% (p = 0.012) and 66.9% (p = 0.008), respectively. Acute lymphopenia accompanied by elevated CRP levels was noted in 8 patients in the 48 h after first pamidronate infusion. Maximal rate and magnitude of enhanced MRI signal after gadolinium augmentation decreased after pamidronate therapy, especially in the bone marrow. CONCLUSION: Preliminary data from uncontrolled studies support the efficacy of pamidronate therapy for NSAID refractory SpA and warrant further evaluation in controlled trials.

Adult↗
PubMed1999

[Associated fracture of the posteromedial tubercle and the lateral process of the talus: a case report. Contribution of computed tomography].

PURPOSE OF THE STUDY: Fracture of lateral process of the talus is an uncommon injury, fracture of the posteromedial tubercle of the talus is quite rare, and association of the two lesions is not reported previously. We report a case of an associated fracture of posteromedial tubercle an lateral process of the talus. PATIENT AND METHODS: The mechanism of injury was forced ankle dorsiflexion and pronation, this mechanism was responsible of an avulsion of the posteromedial tubercle by the postero talotibial ligament and a fracture of lateral process by compression between the lateral malleolus and the calcaneus. RESULTS: Conventional radiographs permitted the diagnosis of the lateral process fracture but the fracture of the posteromedial tubercle was showed only on CT scans. DISCUSSION: The fracture of the posteromedial tubercle was treated by internal fixation, through a posteromedial approach. At 12 months follow-up the patient was able to walk without pain and radiographic result was excellent (no avascular necrosis of the tubercle and no Arthrosis of subtalar joint).

Adult↗
PubMed1998

An open study of pamidronate in the treatment of refractory ankylosing spondylitis.

OBJECTIVE: Bisphosphonates inhibit the development of delayed type hypersensitivity chronic inflammation and suppress inflammation and cartilage/bone erosion in diverse murine arthritis models. We evaluated antiinflammatory properties of the bisphosphonate pamidronate in patients with ankylosing spondylitis (AS) refractory to nonsteroidal antiinflammatory drugs. METHODS: Patients included 14 men and 2 women. The first group of 8 patients (Group 1) received pamidronate as a 30 mg intravenous infusion once a month for 3 months, followed by a 60 mg dose once a month for an additional 3 months. Eight additional patients (Group 2) received only the 60 mg dose once a month for 3 months. Clinical assessments included the BASDAI (Bath AS Disease Activity Index), BASFI (Functional Index), and BASMI (Metrology Index), and laboratory assessments hemoglobin and erythrocyte sedimentation rate (ESR) at baseline and one month after final 60 mg dose of pamidronate. Mean BASDAI score at study entry was 6.7 for both groups. RESULTS: A significant improvement was observed in disease activity score in Group 1 after 6 monthly infusions of pamidronate (mean BASDAI 4.21; p = 0.03), in the BASMI score (p = 0.01), and the ESR (p = 0.009). A significant improvement in the BASMI was noted in Group 2 patients (p = 0.007) after 3 monthly infusions of pamidronate, but not in the BASDAI score (mean 5.01; p = 0.07) or the ESR (p = 0.12). CONCLUSION: Preliminary data suggest pamidronate may possess antiinflammatory activity in patients with AS, particularly with prolonged administration; this agent deserves further evaluation in a controlled trial.

Adult↗
PubMed1997

Analysis of measurements of slip resistance of soiled surfaces on site.

The present study hinges on the use of the PFT (Portable Friction Tester) to assess the slip resistance of floors on site and aims to analyse measurements of slip resistance (602 measurements) that were carried out in 27 different firms on moistened, greasy or dirty floors. The contribution of different factors to the slipperiness of a given soiled surface can thus be identified or confirmed: quantity and viscosity of the soil, permeability and roughness of the floor, cleaning efficiency and uniformity. In particular, we observed that cleaning a soiled surface does not immediately lead to an increase in its slip resistance. The present study is exploratory in nature since so far no publication has been devoted to the analysis of measurements of slip resistance of floors in more than one firm.

Accidental Falls↗
PubMed1995

Melibiose permease of Escherichia coli: large scale purification and evidence that H+, Na+, and Li+ sugar symport is catalyzed by a single polypeptide.

As much as 20-30 mg of functional recombinant melibiose permease (Mel-6His permease) of Escherichia coli, carrying a carboxy-terminal affinity tag for metallic ions (six successive histidines), can be routinely purified from 10 g of cells (dry weight) by combining nickel chelate affinity chromatography and ion exchange chromatography. Mel-6His permease was constructed by modifying the permease gene (melB) in vitro and then overproduced in cells transformed with multicopy plasmids. The tagged permease was efficiently solubilized in the presence of 3-(laurylamido)-N,N'-dimethylaminopropylamine oxide (LAPAO) and high sodium salt concentration and then selectively adsorbed on a nickel nitrilotriacetic acid (Ni-NTA) affinity resin. After the replacement of LAPAO by n-dodecyl beta-D-maltoside to maintain the activity of the soluble permease in low ionic strength media, the permease-enriched fraction (> 90%) was eluted with 0.1 M imidazole and finally purified to homogeneity (> 99%) using ion exchange chromatography. Determination of the permease N-terminal sequence shows that an initiating methionine is missing and that a Ser-Ile-Ser stretch precedes the postulated primary amino acid sequence. Purified permeases, reconstituted in liposomes, display H(+)-, Na(+)-, or Li(+)-dependent sugar binding and active transport activities similar to those of the native permease in its natural environment, proving that all three modes of symport activity are mediated by one and the same polypeptide.

Amino Acid Sequence↗
PubMed1995

[Bousquet's device in the treatment of recurrent dislocation of a total hip prosthesis. Apropos of 13 cases].

PURPOSE OF THE STUDY: Dislocation following total hip arthroplasty (THA) continues to be a problem. An innovative treatment is described with the intermediate Bousquet's prosthesis. This study reported 13 cases and demonstrates its high reliability despite the origins of the dislocation. Recurrent dislocation following initial dislocation, occurs in between 25 to 60 per cent of the cases reported in the literature. The main cause is a malpositioned prosthetic component and especially a retroverted acetabulum. The other reasons for dislocation were: trochanteric non-union, bone or cement impingement, previous surgery, age and neurologic disorder. In every case the instability of the hip may be caused or increased by muscular insufficiency. Various methods are described to control recurrent dislocation: repositioning the component, posterior acetabular wall component, trochanteric advancement, retentive acetabular component, bracing. When the cause is clear and isolated, the rate of success may be 70-80 per cent. This study examines the results of a revision procedure with the intermediate Bousquet's prosthesis. MATERIAL AND METHODS: 13 recurrent dislocations were treated with the intermediate Bousquet's prosthesis. There were 10 women and 3 men with an average age at operation of 73 years. The main cause in 7 cases was an abductor insufficiency including 4 trochanteric non unions. The other causes were 6 component malpositions, 7 previous surgery, 1 impingement. The average delay between the first dislocation and revision was one year. The Bousquet's acetabular component is an steel cup covered with alumina, impacted without cement. The polyethylene component is free in the cup and retentive on the femoral head. The femoral positioning was not modified. RESULTS: The revision did not correct all of the causes of luxation, however we noted only one case of dislocation and no recurrent dislocations. DISCUSSION: At last follow-up, all recurrent dislocations were controlled. Nevertheless, there remained 7 abductor insufficiencies and 4 femoral malpositionings. In the literature the rate of success depends on the cause. The main difficulty is the treatment of joint laxity. Some authors propose trochanteric advancement, a larger head, a posterior wall acetabular component, retentive acetabular component. Success is not uniform. The Bousquet's acetabular component supports joint laxity and femoral malpositioning. This allows to keep the same original femoral component when the risk is too high for a cemented prosthesis or impossible for a non cemented prosthesis. CONCLUSION: This treatment of the recurrent dislocation is reliable with a short and simple operation.

Aged↗
PubMed1987

Development of a carbon-carbon hip prosthesis.

This article deals with the use of carbon-fiber-reinforced-carbon materials for the manufacture of hip prosthesis stems. It considers the manufacturing process of carbon-carbon (C-C) composites made of carbon fibers infiltrated either with dense pyrolytic carbon or silicon carbide (SiC) through chemical vapor infiltration. The chemicophysical properties of these composites are examined according to their structures. The long-term response (2 years) of cortical bone to various types of carbon-carbon was evaluated mainly for bone contact and ingrowth. Carbon-carbon coated with calcium phosphate was found to speed up the bone formation as compared to pyrolytic carbon or SiC coatings. The low modulus of elasticity of the C-C materials could be responsible for quicker bone contact as compared to a much stiffer material like sintered aluminum oxide. The biomechanical performance of C-C hip stems was assessed through (a) implantations into cadaver femurs, (b) fatigue testing, and (c) finite element analysis. These tests showed: (a) a better stress transfer as compared to a metal prosthesis having the same design, (b) no fatigue damage, (c) a computerized stem stress distribution in accordance with the fractures obtained during static mechanical testing.

Biocompatible Materials↗