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Biomedical subjects

R Clavel

Publications and source records attributed to R Clavel.

15 recordsLinked to original sources
PubMed1998

Clinical efficacy of sublingual-swallow immunotherapy: a double-blind, placebo-controlled trial of a standardized five-grass-pollen extract in rhinitis.

Sublingual-swallow immunotherapy (SLIT) using high doses of standardized allergen extracts has been found to be effective in reducing allergic symptoms and medication needs. A double-blind, placebo-controlled study was carried out in a large number of patients to determine whether medication needs can be reduced by SLIT. Some 136 patients with grass-pollen rhinitis with or without mild asthma were studied. Patients received either placebo or SLIT with a standardized grass-pollen extract administered daily with increasing doses up to 300 IR (index of reactivity) from January to the end of July 1994. During the grass-pollen season, patients were instructed to use medications as required and to visit their doctors in case of asthma. Symptom-medications scores were assessed during the pollen season, and serum-specific IgG4 was measured before and at the end of SLIT. In the SLIT group, drug consumption dropped significantly throughout the pollen season (P < 0.02). Moreover, at the peak of the pollen season, betamethasone consumption was significantly reduced in the SLIT group (P < 0.02). Only one patient in the SLIT group had an asthma attack compared to eight patients in the placebo group (P < 0.02). IgG4 levels increased significantly in the SLIT group (P < 0.001) but without correlation with symptoms. Side-effects were comparable in both groups. This study indicates that SLIT in grass-pollen rhinitis is well tolerated, improves overall clinical symptoms, and reduces drug consumption and the need for oral corticosteroids.

Administration, Sublingual↗
PubMed1996

Force feedback for virtual reality based minimally invasive surgery simulator.

This paper presents ongoing research towards an endoscopic surgery simulation system. Our specific application of interest is laparoscopic surgery. The goal is to conceive an endoscopic surgical training tool which allows to realistically simulate the interactions between one or several surgical instruments and the gastrointestinal organs in a virtual reality based environment. An artificial patient is being developed into which endoscopic surgical instruments can be inserted to operate upon virtual organs displayed on a video monitor. In order to achieve a faithful and precise simulation, not only a realistic graphical representation of the organic tissue and its behavior is needed, but also the forces and moments on the surgical instruments encountered during an operation are required to be simulated. The laparoscopic surgery simulator must therefore provide force feedback through the endoscopic instruments manipulated by the surgeon. This paper details the mechanical design of the force feedback mechanisms and addresses some of the technical challenges of this project.

Computer Simulation↗
PubMed1995

[Comparison of study results for levels of specific antibodies using the RAST-IgE method and specific bronchial provocation in children with asthma].

The aim of the study was to evaluate the diagnostic power of specific-IgE evaluation in diagnosis of allergy to house dust mite (Dermatophagoides pteronyssinus, D.pt.), in relation to specific bronchial challenge. In a group of 99 children with perennial asthma, specific-IgE evaluation and bronchial challenge were performed with D.pt. allergens. The bronchial challenge was positive in 52 cases (53%). RAST results were concordant with bronchial challenge from 61% (for classes > or = 1) to 75% (for specific-IgE level > 9.5 PRU/ml). The sensitivity for RAST class 1 was 88%, but its specificity did not exceed 30% as opposed to 54% and 91%, respectively for class 4. The best overall concordance would be obtained with RAST class 3-4 or a specific IgE level of at least 9.5 PRU/ml but 25% would still be discordant and distributed among false-negatives and false-positives, for whom outside bronchial challenges, a sure diagnosis cannot be guaranteed.

Adolescent↗
PubMed1982

[Respiratory-tract-directed immunostimulation by a vaccine administered by the oral route].

For testing the respiratory immunizing efficacy of an oral vaccine, 61 volunteer subjects were vaccinated with a double blind ribosomal vaccine. Although no clinical progress was observed in the treated group, there was however a significant rise in specific antibodies against each bacteria. In contrast, no rise in total seric immunoglobulins could be observed. The study of 115 salivary and bronchial IgA showed a significant rise in bronchial 11s IgA in the treated children's group. This data suggested the hypothesis of a stimulation of the whole immunosecretory system (mucous) by the vaccinotherapy alone by the oral route.

Administration, Oral↗