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Biomedical subjects

L Meunier

Publications and source records attributed to L Meunier.

At least 19 recordsLinked to original sources
PubMed1992

Treatment of psoriasis with a 311-nm UVB lamp.

In a left-right comparative study, the Philips TL-01 sunlamp, a new UVB fluorescent lamp, was evaluated in 15 patients with symmetrical psoriasis. One half of the body was treated in a cabin containing TL-01 lamps, and the other half in a cabin containing TL-12 lamps. The patients were treated three times/week, and the study was conducted in a randomized, double-blind fashion. The percentage response of psoriatic lesions was determined on the tenth and twentieth exposures. The therapeutic effect of the TL-01 lamps was superior to that of the TL-12 lamps, and treatment was better tolerated, particularly with regard to episodes of burning. This new lamp appears to provide more effective and safer phototherapy for psoriasis.

Adult↗
PubMed1992

[Narrow-band UVB phototherapy (Philips TL01 lamps) in psoriasis].

The authors report the results of an open study conducted on 53 patients with psoriasis treated by narrow-band UVB phototherapy, using Philips' TL01 lamp. With a simple procedure which did not require MED determination this treatment gave satisfactory results in 92 p. 100 of the cases, with mild burns in only 9 p. 100. The morphological type of psoriasis (patchy, guttate or nummular) had no influence on the therapeutic result, but the degree of infiltration of the lesions and their location on the lower limbs proved to be a factor of relative resistance. In most patients the results were obtained in 20 sessions with a mean cumulative dose of 20.19 +/- 2.7 J/cm2. Some patients had an additional treatment of 6 sessions. The results obtained with Philips' TL01 lamp were as satisfactory as those obtained with the conventional UVB lamps, but the TL01 lamp seemed to be easier to handle and better tolerated, which gives them some advantages over the latter.

Adolescent↗
PubMed1991

[Light-induced aging of the skin].

Ageing of the skin results from the synergistic effects of intrinsic, genetically determined factors and extrinsic factors the most important of which is chronic exposure to sunlight. The cumulative effects of ultraviolet radiations are responsible for specific dermo-epidermal alterations (actinodermatitis) with its two main manifestations: actinic elastosis characterized by accumulation of dystrophic fibres in the dermis, and lesions of senile keratosis which may become carcinomas. The so-called "premature ageing of the skin" can be alleviated by cosmetic treatments, photoprotective measures and vitamin A derivatives; regular applications of retinoic acid (vitamin A acid, tretinoin) can result in partial regression of actinodermatitis.

Epidermis↗
PubMed1991

Technique for quantification of LTB4-induced changes in peripheral granulocyte counts in vivo in the rabbit.

A method to quantify leukotriene B4-(LTB4)-induced changes in peripheral granulocyte counts in the rabbit is described. Rabbits were surgically prepared with vascular access ports cannulating the right external jugular vein. This preparation made possible rapid, accurate, and repeated sampling of venous blood. Intravenous infusion of LTB4 (0.5-2 micrograms/mL) into the left marginal ear vein was found reproducibly to cause an initial, rapid (1-5 min) leukopenia (64%-100% reduction) followed by an extended (20-30 min) leukocytosis (121%-178% increase). Saline infusion for 30 min resulted in no changes in peripheral granulocyte number. The method described was sensitive and reproducible enough to allow evaluation of the LTB4 receptor antagonist, LY223982 (10 mg/kg, i.v.), which was shown to block both the leukopenia and the leukocytosis induced by LTB4 infusion.

Animals↗
PubMed1990

[Then physiopathology of atopic dermatitis].

Atopic dermatitis is transmitted as an autosomal dominant trait. Its expressivity is variable, and flare-ups are triggered by environmental factors such as air-borne allergens, cutaneous flora or foodstuffs. Elevation of serum IgE levels is inconstant and not specific; it is associated with a deficiency of suppressor T cell population. The epidermis contains IgE bound to the surface of Langerhans cells; this abnormality seems to be specific as it is not found in atopic or non atopic healthy subjects. The lack of beta-adrenergic response is partially explained by the hyperactivity of the cyclic AMP-degrading phosphodiesterase. Disturbances in essential fatty acid metabolism (inactivation of delta 6 desaturase) are thought to be responsible for abnormalities in the permeability of epithelial structures. The relationships between pharmacological, biochemical and immunological dysregulations are unknown.

Dermatitis, Atopic↗
PubMed1990

Specific effects of retinoic acid on the skeletal morphogenesis of the 11-day mouse embryo forelimb bud in vitro.

Using our improved method for culturing 11-day mouse forelimb buds in vitro, we have investigated the effects of a local application of all-trans-retinoic acid (RA) on growth, cartilaginous differentiation and skeletal patterning in the mammalian limb bud. Carrier implants of catgut impregnated with DMSO or various doses of RA in DMSO were inserted at the apex of the buds in the proximo-distal axis just beneath the apical ectodermal ridge. After 6 days of culture, cartilaginous skeletons were stained and explants were processed for morphological analysis and quantitative study using computerized optical image analysis. Buds treated with low doses of RA exhibited stimulated growth and chondrogenesis. Moreover, hypertrophied and fused metacarpals were seen within explants treated with the lowest dose. High doses strongly inhibited growth and skeletal morphogenesis. An intermediate dose sustained cartilaginous differentiation at the same level as low doses, but concomitantly disturbed the skeletal pattern. These results are discussed considering reported RA effects on other experimental systems including avian limb bud as an in vivo model or cell cultures as an in vitro simplified model.

Animals↗
PubMed1988

[Does plasma exchange have a place in the treatment of necrotizing angiodermatitis?].

Necrotizing angiodermatitis is of characteristic clinical expression and is often difficult to treat. It is associated with microcirculatory disorders of hypertensive or diabetic origin. A particularly long course (m = 8 months) in 8 patients with necrotic angiodermatitis (of hypertensive origin in 6 cases and diabetes in 2) resulted in treatment by plasma exchange, two other patients with immunological angiodermatitis being treated similarly because of very similar symptomatology. The 10 patients (3 men, 7 women age range 55 to 80 years) received between 4 and 18 small volume plasma exchanges over 2 to 12 weeks. Results were evaluated from pain and duration of healing, absence of pain being reported by 7 patients and a beneficial effect on healing by 6 patients. No correlation existed between ESR and hematocrit values during treatment and the clinical course. The question arises as to whether the mode of action of plasma exchange in angiodermatitis is related to the purifying of serum factors or a rheological role.

Aged↗
PubMed1987

New in vitro procedures for experimental studies on the development of 11-day mouse embryo forelimb buds.

A new method has been developed for culturing 11-day mouse forelimb buds in vitro. In cultures performed with conventional procedures, skeletal pieces frequently appeared distorted and reduced in size. Moreover, forelimb buds explanted from embryos younger than a stage corresponding to 50 pairs of somites developed narrow hand plates devoid of radiated autopods. By contrast, in the new procedure using media supplemented with fetal calf serum and growth factors and enhancing distal feeding with carrier implants of catgut, enlarged pads were obtained that exhibited at least 4 digital rays in buds explanted from embryos with 40-44 pairs of somites. Compared with conventional procedures, the mean value of DNA content per limb bud was twice as great with use of our improved method. The ability of limb bud cells to proliferate and differentiate when cultured either in classical or in modified conditions, and the importance of the technical procedures, are discussed in the new prospect of in vitro developmental studies.

Animals↗
PubMed1986

[Systemic scleroderma. Contribution of esophageal manometry].

Oesophageal motor function was studied by oesophageal manometry in 48 patients with progressive systemic sclerosis: 25 with proximal scleroderma and 23 with diffuse scleroderma. Oesophageal lesions were noted in 70% (74% in diffuse scleroderma; 64% in proximal scleroderma). Classical manometric signs of scleroderma were found in only 31% of patients. Peristaltic modifications might begin at the junction of the two muscular coats, since a four centimeter long aperistaltic suspended area was noted in that region in 20% of patients, especially in the proximal scleroderma group. Oesophageal motility and low lower oesophageal sphincter pressure account for the gastro-oesophageal reflux and may compromise respiratory function, as suggested by the high frequency of concurrent oesophageal and respiratory dysfunction in diffuse scleroderma. Systematic prevention of gastro-oesophageal reflux should perhaps be advocated as soon as abnormalities in oesophageal motility are diagnosed.

Adolescent↗
PubMed1986

Chondrogenesis in mouse limb buds in vitro: effects of dibutyryl cyclic AMP treatment.

We studied the effects of dibutyryl cyclic AMP (dbcAMP) on mouse limb-bud chondrogenesis at three stages of embryonic development. After 24 h of culture, limb buds with or without a covering of ectoderm were treated with 1 mM dbcAMP for 48 h and were then compared with untreated cultured limb buds. Treatment with dbcAMP enhanced cartilaginous differentiation in organ cultures of stage-17 and -19 (according to Theiler's) limb buds, although the presence of ectoderm reduced the level of dbcAMP stimulation. By stage 20, treatment with dbcAMP irreversibly inhibited cartilaginous differentiation. These results suggest that the responsiveness of mesenchymal limb-bud cells to dbcAMP is stage related. The results of histological studies as well as of analyses of DNA content and sulphated glycosaminoglycan accumulation supported the hypothesis that dbcAMP treatment induces recruitment of initially non-chondrogenic cells whose commitment explains the enhancement of cartilaginous differentiation. Limb-bud competence for chondrogenesis throughout the three developmental stages studied is also discussed.

Animals↗
PubMed1986

[Chronic herpes of the pyodermatitis vegetans type in chronic cutaneous lymphoid leukemia].

The authors report a case of chronic herpes virus infection of the face which developed in a 70-year old man already affected with chronic lymphocytic leukaemia of the B-cell type (CLL-B) with specific cutaneous localisations. Immunodepression was indicated only by marked hypogammaglobulinaemia. Cell-mediated immunity was preserved. The cutaneous lesions of the face were chronic and presented as pyodermatitis vegetans. A one-week course of acyclovir administered by intravenous infusion in doses of 5 mg/kg three times a day resulted in rapid and dramatic cure, but this result proved transient, since the virus infection relapsed 2 1/2 months later. The new episode also was successfully treated with a second course of acyclovir. The herpes virus infection had developed only on those skin areas that were specifically affected by the leukaemia; after treatment and eradication of the virus, massive lymphocytic infiltration of the dermis persisted in these areas. Involvement of the skin is rare in CLL-B and has been reported mainly in CLL-T. The lesions most frequently encountered are tuberous and papular lesions and infiltrated plaques on the forehead and ears. The pyodermatitis vegetans presentation is unusual. The reasons why viral skin lesions develop on those caused by leukaemia are unknown.

Acyclovir↗