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Biomedical subjects

J Lemaire

Publications and source records attributed to J Lemaire.

At least 19 recordsLinked to original sources
PubMed2002

Gas phase infrared spectroscopy of selectively prepared ions.

The first example of direct structural characterization of polyaromatic ions by coupling a Fourier transform ion cyclotron resonance mass spectrometer with an infrared free-electron laser is presented. Measurement of the IR spectra of selectively prepared ionic reactive intermediates is allowed by the association of the high peak power and wide tunability of the laser with the flexibility of the spectrometer, where several mass selection and ion reaction steps can be combined, as demonstrated in the case of iron cation complexes of hydrocarbons. The present experimental setup opens the way to understanding chemical reaction paths.

Journal Article↗
PubMed2002

Calibration results obtained with Liulin-4 type dosimeters.

The Mobile Radiation Exposure Control System's (Liulin-4 type) main purpose is to monitor simultaneously the doses and fluxes at 4 independent places. It can also be used for personnel dosimetry. The system consists of 4 battery-operated 256-channel dosimeters-spectrometers. We describe results obtained during the calibrations of the spectrometers at the Cyclotron facilities of the University of Louvain, Belgium and of the National Institute of Radiological Sciences-STA, Chiba, Japan with protons of energies up to 70 MeV. The angular sensitivities of the devices are studied and compared with Monte-Carlo predictions. We also present the results obtained at the HIMAC accelerator with 500 MeV/u Fe ions and at the CERN high energy radiation reference fields. Records made during airplane flights are shown and compared with the predictions of the CARI-6 model.

Aerospace Medicine↗
PubMed2002

Cost-benefit and cost-effectiveness analysis of a disability prevention model for back pain management: a six year follow up study.

AIMS: To test the long term cost-benefit and cost-effectiveness of the Sherbrooke model of management of subacute occupational back pain, combining an occupational and a clinical rehabilitation intervention. METHODS: A randomised trial design with four arms was used: standard care, occupational arm, clinical arm, and Sherbrooke model arm (combined occupational and clinical interventions). From the Quebec WCB perspective, a cost-benefit (amount of consequence of disease costs saved) and cost-effectiveness analysis (amount of dollars spent for each saved day on full benefits) were calculated for each experimental arm of the study, compared to standard care. RESULTS: At the mean follow up of 6.4 years, all experimental study arms showed a trend towards cost benefit and cost effectiveness. These results were owing to a small number of very costly cases. The largest number of days saved from benefits was in the Sherbrooke model arm. CONCLUSIONS: A fully integrated disability prevention model for occupational back pain appeared to be cost beneficial for the workers' compensation board and to save more days on benefits than usual care or partial interventions. A limited number of cases were responsible for most of the long term disability costs, in accordance with occupational back pain epidemiology. However, further studies with larger samples will be necessary to confirm these results.

Absenteeism↗
PubMed2001

Implementation of a participatory ergonomics program in the rehabilitation of workers suffering from subacute back pain.

This paper describes a participatory ergonomics program aimed at early return to regular work of workers suffering from subacute occupational back pain and assesses the perceptions of the participants on the implementation of ergonomic solutions in the workplace. The participatory ergonomics program was used in the rehabilitation of workers suffering from subacute back pain for more than 6 weeks, a program that was associated with an increased rate of return to work. The perceptions of the participatory ergonomics participants were assessed 6 months after completion of the ergonomic intervention through a questionnaire sent to employer representatives, union representatives and injured workers of participating workplaces. About half of the ergonomic solutions were implemented according to the perception of the participants, with a substantial agreement between respondents.

Ergonomics↗
PubMed2000

Disability measurement in persons with back pain: a validity study of spinal range of motion and velocity.

OBJECTIVE: To evaluate the criterion validity and responsiveness to change of spine kinematic variables to assess disability in patients with low back pain. DESIGN: Blinded comparison between spine kinematic variables, Oswestry disability questionnaire scores, and work status. SETTING: Multidisciplinary occupational rehabilitation clinic of a university hospital. PATIENTS: Population-based cohort of 111 patients with subacute work-related back pain who were absent from regular work for more than 4 weeks because of back pain. INTERVENTIONS: This study was part of a population-based randomized clinical trial. Patients were randomized to 4 different methods of management: usual care, rehabilitation, ergonomics, or rehabilitation and ergonomics. MAIN OUTCOME MEASURES: Oswestry disability questionnaire, kinematic analysis of the spine during flexion and extension of the trunk, and work status were collected at weeks 4, 12, 24, and 52 after the back accident. RESULTS: Kinematic variables were poorly to moderately related to work status and Oswestry questionnaire scores. Kinematic variables were also unresponsive to change in work status and Oswestry questionnaire scores over time. CONCLUSION: Spine kinematics during flexion and extension of the trunk do not appear to be a valid measure of disability in patients with subacute and chronic back pain.

Adult↗
PubMed2000

Genetic testing for breast and ovarian cancer: implications for life insurance.

As the science of genetic testing progresses, the debate surrounding the uses of genetic information intensifies. In February, President Clinton signed an executive order prohibiting federal agencies from using such information to make hiring, promotion, or placement decisions. Concerns about privacy and discrimination have led many states to propose or enact statutes that prohibit health insurers from using genetic test results in their underwriting decisions. However, few statutes address access to these results by the life insurance industry. This Issue Brief summarizes the current debate on whether life insurers should have access to genetic testing information for breast and ovarian cancer, and provides actuarial insight into the potential effect of such testing on the voluntary term insurance market.

Breast Neoplasms↗
PubMed1999

Space travel directly induces skeletal muscle atrophy.

Space travel causes rapid and pronounced skeletal muscle wasting in humans that reduces their long-term flight capabilities. To develop effective countermeasures, the basis of this atrophy needs to be better understood. Space travel may cause muscle atrophy indirectly by altering circulating levels of factors such as growth hormone, glucocorticoids, and anabolic steroids and/or by a direct effect on the muscle fibers themselves. To determine whether skeletal muscle cells are directly affected by space travel, tissue-cultured avian skeletal muscle cells were tissue engineered into bioartificial muscles and flown in perfusion bioreactors for 9 to 10 days aboard the Space Transportation System (STS, i.e., Space Shuttle). Significant muscle fiber atrophy occurred due to a decrease in protein synthesis rates without alterations in protein degradation. Return of the muscle cells to Earth stimulated protein synthesis rates of both muscle-specific and extracellular matrix proteins relative to ground controls. These results show for the first time that skeletal muscle fibers are directly responsive to space travel and should be a target for countermeasure development.

Animals↗
PubMed1999

Prevalence of GBV C/HGV RNA and GBV C/HGV antibodies in French volunteer blood donors: results of a collaborative study.

BACKGROUND AND OBJECTIVES: Posttransfusion hepatitis still occurs at an incidence of about 1 in 118,000 for HBV and 1 in 220,000 for HCV. This collaborative study aimed to determine the prevalence of a novel flavivirus, GBV-C/HGV, even though its role in transfusion-associated hepatitis is uncertain. MATERIALS AND METHODS: GBV-C/HGV RNA was detected by PCR using either the Boehringer detection kit or by primers previously described. HGV antibodies were detected by a serological assay from Boehringer. RESULTS: The observed GBV-C/HGV RNA frequency was 3.4%. HGV antibodies occurred in 9.5% of donors. CONCLUSION: In our study, 12. 9% of the donors had been in contact with the GBV-C/HGV virus.

Adolescent↗
PubMed1998

Is work status of low back pain patients best described by an automated device or by a questionnaire?

STUDY DESIGN: A prospective cohort study of patients with subacute occupational back pain. OBJECTIVES: To study the relation between a marketed opto-electric device measuring trunk kinematics, a widely used specific functional capacity questionnaire, and work status in back pain patients, and to assess the responsiveness to change in work status of the opto-electric device and the questionnaire. SUMMARY OF BACKGROUND DATA: Several instruments have been developed to evaluate the functional capacities of patients with back pain, but the relation between these instruments and work status has rarely been studied. METHODS: The relation between the opto-electric device, the questionnaire, and work status in patients with back pain was evaluated. The study population was a prospective cohort of patients with subacute back pain who were absent from regular work for more than 4 weeks. All data were compiled blindly on the same day, at study entry (4 weeks after work accident), and at 12, 24, and 52 weeks after the work accident. The validity of the questionnaire and opto-electric device scores was assessed with partial correlation analyses, standardized response mean, logistic regression analyses, and receiver operating characteristics curves. RESULTS: The correlation between the questionnaire and opto-electric device scores was low. The questionnaire scores were significantly related to work status, but the opto-electric device scores were not. The questionnaire was responsive to change in work status, whereas the opto-electric device was not. CONCLUSIONS: The opto-electric device scores were not related to either functional capacity scores (questionnaire) or work status in patients with low back pain, and the opto-electric device was not responsive to change in work status. Conversely, the questionnaire was related to work status and was responsive to change in work status.

Activities of Daily Living↗
PubMed1997

A population-based, randomized clinical trial on back pain management.

STUDY DESIGN: Population-based randomized clinical trial. OBJECTIVES: To develop and test a model of management of subacute back pain, to prevent prolonged disability. SUMMARY OF BACKGROUND DATA: The present management of back pain seems inadequate, and development of innovative models has been urged. METHODS: A model for the treatment of subacute work-related back pain has been developed and evaluated in a population-based randomized clinical trial. Workers (n = 130) from eligible workplaces in the Sherbrooke area (N = 31), who had been absent from work for more than 4 weeks for back pain, were randomized, based on their workplace, in one of four treatment groups: usual care, clinical intervention, occupational intervention, and full intervention (a combination of the last two). The duration of absence from regular work and from any work was evaluated using survival analysis. Functional status and pain were compared at study entry and after 1 year of follow-up. RESULTS: The full intervention group returned to regular work 2.41 times faster than the usual care intervention group (95% confidence interval 1.19-4.89; P < 0.01). The specific effect of the occupational intervention accounted for the most important part of this result, with a rate ratio of return to regular work of 1.91 (95% confidence interval = 1.18-3.10; P < 0.01). Pain and disability scales demonstrated either a statistically significant reduction or a trend toward reduction in the three intervention groups, compared with the trend in the usual care intervention group. CONCLUSIONS: Close association of occupational intervention with clinical care is of primary importance in impeding progression toward chronicity of low back pain.

Adolescent↗
PubMed1996

Tissue-engineered skeletal muscle organoids for reversible gene therapy.

Genetically modified murine skeletal myoblasts were tissue engineered in vitro into organ-like structures (organoids) containing only postmitotic myofibers secreting pharmacological levels of recombinant human growth hormone (rhGH). Subcutaneous organoid implantation under tension led to the rapid and stable appearance of physiological sera levels of rhGH for up to 12 weeks, whereas surgical removal led to its rapid disappearance. Reversible delivery of bioactive compounds from postmitotic cells in tissue engineered organs has several advantages over other forms of muscle gene therapy.

Animals↗
PubMed1996

Calculating low-altitude trapped particle fluxes with the NASA models AP-8 and AE-8.

Accessing the NASA trapped radiation models AP-8 and AE-8 with (B,L) values obtained with modern geomagnetic field models causes an unrealistic secular increase of the predicted flux over low altitude orbits. We show the secular variation of the orbit-averaged particle flux along the LDEF orbit and the mission dose, obtained using the AP-8 trapped radiation models with an epoch-dependent magnetic field. The artificially increased epoch-dependent fluxes and doses are compared to the flux and dose obtained with a consistent and more correct procedure for predicting fluxes with the NASA models. This procedure has been implemented in the radiation analysis software package UNIRAD developed and distributed by BIRA-IASB.

Atlantic Ocean↗
PubMed1992

Optimal therapeutic level of heparin therapy in patients with venous thrombosis.

BACKGROUND: Audits of heparin sodium therapy suggest that heparin administration is fraught with difficulty. The literature indicates that the current clinical practice of intuitive ordering of heparin results in inadequate therapy because of fear of bleeding. The importance of exceeding the lower limit of the therapeutic range has been strongly supported by findings of prospective clinical trials. Firm evidence indicates that failure to exceed the lower limit is associated with unacceptably high rates of recurrent venous thromboembolism. By comparison, evidence supporting the risk of exceeding the upper limit of the therapeutic range is weak. OBJECTIVES: The purposes of this study were (1) to validate prospectively an approach designed to minimize the proportion of patients receiving subtherapeutic doses of heparin and (2) to determine the effectiveness and safety of decreasing the heparin dosage infused on the basis of activated partial thromboplastin time (APTT) prolongation reflecting both heparin and warfarin sodium effects. METHODS: We performed a randomized double-blind study evaluating a prescriptive approach to heparin administration in patients receiving heparin or heparin with warfarin. Thromboembolic and bleeding complications were objectively documented. RESULTS: Only 1% and 2% of patients had subtherapeutic heparin levels for 24 hours or more in the heparin and combined groups, respectively. Recurrent venous thromboembolism occurred infrequently in both groups (7%). Sixty-nine (69%) of 99 patients receiving combined therapy had supratherapeutic values, compared with 24 (24%) of 100 receiving heparin; bleeding complications occurred in 9% and 12%, respectively. CONCLUSIONS: Our findings demonstrate that no association exists between supratherapeutic APTT responses and bleeding, which is in direct contrast to the observed association between subtherapeutic APTT responses and recurrent venous thromboembolism.

Double-Blind Method↗
PubMed1991

[Development and evaluation of a laser catheter with tip fiberoptic for coronary angioplasty].

A fiber-optic tip catheter has been developed for treating coronary and peripheral atherosclerosis percutaneously. The catheter is coupled to an ionised Argon laser emitting at an optical power of 1 to 7 Watts. It is designed to follow a guide wire and to perform tissue ablation by a new concept combining the effects of central vaporisation and peripheral thermal remodelling of the obstructed artery. This mode of function should considerably reduce the risks of false route previously encountered with laser angioplasty. The optical and thermic properties of the catheter prototypes were determined by physical methods. These experiments showed that the temperature of the metallic component of the catheter tip did not exceed 30 degrees C at a continuous power of 6 laser Watts when the flush was functioning. It attained 400 degrees C in the absence of the flush. The performances of the catheter were then tested in a number of in vitro experiments. First of all, the catheter tip was placed perpendicularly to atheromatous cadaver aortae to study the effect of vaporisation with respect to the laser power. The threshold of vaporisation was 1 Watt (irradiance: 1100 Watts/cm2). The catheter was then introduced into plastic tubes obstructed by atheromatous plaques. This experiment demonstrated the mechanical solidity of the catheter and its flexibility in difficult operating conditions: diameter 2mm, 45 degrees angles, irregular calcified plaques. It also showed that the optimal safety-efficacy laser power was 3 laser Watts and that the exposure times varied with respect to the nature of the plaques tested.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗