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Biomedical subjects

M C Poelman

Publications and source records attributed to M C Poelman.

12 recordsLinked to original sources
PubMed1992

Toxic effects and detection of oxygen free radicals on cultured articular chondrocytes generated by menadione.

The aim of this work was to study the proliferation pathological perturbations of cultured chondrocytes in response to menadione, an oxygen free radicals producing drug. Rabbit articular chondrocytes in monolayer culture were treated with 10(-5) M, 1.5.10(-5) M and 2.10(-5) M of menadione during three days. A dose dependent decrease of the proliferative capacity was observed. Flow cytometry analysis revealed a perturbation of the cell cycle progression consisting in an accumulation of cells in the S and G2 + M phases. This growth perturbation was due to oxygen radicals production since a treatment with catalase suppressed these toxic effects. Furthermore, to identify oxygen derived radicals in the cellular suspension of cultures treated with menadione, we used a technique of spin-trapping coupled with electron spin resonance (ESR). The ESR signal corresponding to the DMPO hydroxyl radical adduct (DMPO-OH) has been detected. The spectra observation indicated the actual production of hydroxyl radical. However, superoxide anions have not been identified; this fact can be explained by the low reactivity of these anions with DMPO and by the decomposition of signal DMPO-OOH to DMPO-OH.

Animals↗
PubMed1989

Assessment of topical non-steroidal anti-inflammatory drugs.

A new non-invasive technique for assessing the efficacy of topical non-steroidal anti-inflammatory drugs (NSAID) in man is proposed. The NSAID are initially applied to the skin under occlusion before inflammation is induced by a methyl nicotinate solution. The inflammatory response is quantified in terms of cutaneous blood flow by a laser Doppler velocimeter (LDV). The efficacy of NSAID preparations is calculated by comparing the responses of the LDV to the methyl nicotinate challenge on the pretreated and the non-treated skin sites. This protocol has been used to investigate the effect of three different NSAID preparations (indomethacin, niflumic acid, palmitoyl collagenic acid) and the influence of the vehicle on the efficacy of indomethacin. The three preparations tested gave positive results but with different amplitudes in response. The efficacy of indomethacin varied with the vehicle used.

Administration, Topical↗
PubMed1988

Are corneocytes elastic?

By using a microhandling system, we have recorded the force necessary to elongate isolated corneocytes. According to certain hypothesis, it appears that the elastic modulus of corneocyte is far higher than that of stratum corneum itself. Aggregates of corneocytes are disassembled by forces with a wide range of intensity. In the light of these experiments, stratum corneum appears as a very supple material where the deformations occur more by a plastification of the intercellular medium and an unfolding of the microrelief lines than an elongation of the corneocytes themselves. Moreover, desmosomes remnants could play a certain role in the corneocytes cohesiveness.

Cell Adhesion↗
PubMed1985

New experimental approach to measure the skin-reflected light. Application to cutaneous erythema and blanching.

By modifying the blood supply in the upper part of the dermis, the colour of the skin is changed by any material in contact with it. This is a great difficulty when we want to measure the colour intensity in erythema or blanching. To avoid this problem, we designed and built a device which measures the skin reflectance value without any contact with the skin. The use of this device on man to study the skin blanching after application of dermocorticoids allows us to determine the more potent drug among a series (clobetasol propionate) and, for a given drug (betamethasone), the more efficient preparation (oil-in-water emulsion). The study of the effect of increasing irradiation doses of ultraviolet light show that the sensitivity of the device is equivalent to that of the clinical assessment and that the relationship between the irradiation dose and the skin reflectance is sigmoidal.

Betamethasone Valerate↗