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Biomedical subjects

P Amblard

Publications and source records attributed to P Amblard.

At least 19 recordsLinked to original sources
PubMed1995

Does manganese protect cultured human skin fibroblasts against oxidative injury by UVA, dithranol and hydrogen peroxide?

Reactive oxygen species (ROS) are involved in the mechanism of photoaging and carcinogenesis. Skin is endowed with antioxidant enzymes including superoxide dismutases (SOD): cytosolic copper zinc SOD and mitochondrial manganese SOD. The aim of our study was to estimate the protective effect of manganese against oxidative injury on cultured human skin fibroblasts. Dithranol, hydrogen peroxide and UV-A radiation (375 nm) were employed as oxidative stressors. The supply of manganese chloride produced an increase in cellular content of this element up to 24 fold without concomitant elevation of MnSOD activity. Nevertheless, manganese protects cells against two of the three ROS generating systems assessed, namely hydrogen peroxyde and UV-A. This protective effect depends on the concentration of manganese in the medium, 0.1 mM and 0.2 mM protect against UVA cytotoxicity, only 0.2 mM protects against H2O2 cytotoxicity.

Anthralin↗
PubMed1993

[Systemic mastocytosis: incidence and risks of vasomotor seizures].

We report on 9 cases of systemic mastocytosis which underline the frequency and the potential severity of this disease. All patients had intercritical signs (usually urticaria). Seven patients had also typical crises with flush and vascular collapses are observed together, doctors should measure histamine blood level and perform correct biopsy.

Histamine Release↗
PubMed1992

[Skin diseases with photosensitivity].

Skin diseases associated with photosensitivity are numerous and may be divided into three main groups: photo-aggravated dermatoses, genophotodermatoses and metabolic photodermatoses. Photo-aggravated dermatoses are autonomous skin diseases in which exposure to sunlight may make the disease worse or precipitate its onset and/or its progressiveness; this group includes lupus erythematosus, autoimmune bullous diseases, acantolytic dyskeratoses, acne vulgaris, rosacea and cutaneous lymphoid infiltrates. To these must be added photosensitive forms of autonomous dermatoses such as atopic dermatitis, psoriasis, herpes labialis, erythema multiforme, granuloma and disseminated superficial actinic porokeratosis. Genophotodermatoses are genodermatoses which are made photosensitive by a recognized or as yet unidentified deficiency of the natural photoprotection system. In this group are albinism, vitiligo, xeroderma pigmentosum and poikiloderma. Metabolic photodermatoses are diseases in which photosensitization reactions, often revealing, are due to the accumulation in the skin of an endogenous chromophore as a result of a congenital (porphyria) or acquired (pellagra) enzymatic disorder.

Humans↗
PubMed1991

UV-induced squamous cell carcinomas in the hairless mouse. Morphological characteristics and transplantation in the syngenic and nude mouse.

Squamous cell carcinomas were induced by UVB in the hairless mouse HRO hr/hr. Twelve mice were irradiated three times a week at a dose of 0.19 J/cm2. The average latency period for the appearance of the first tumour is 16 weeks and by the 21st week, tumour incidence is 100%. Further observation of these tumours shows that their growth is independent of irradiation dose and that the tumours continue to appear even after cessation of irradiation. Histological and cytological examination of these tumours show them to have characteristics of malignancy. Transplantation in athymic mice suggests that UVB provokes immune deficiencies in hairless mice similar to those seen in conditioned nude mice.

Animals↗
PubMed1991

Psoralen plus ultraviolet A in the prophylactic treatment of benign summer light eruption.

We report the results of a French multicentre study to evaluate the efficiency of psoralen plus ultraviolet A (PUVA) therapy in the prophylactic treatment of benign summer light eruption (BSLE) and to establish the optimal protocol of radiation. Nine photobiology centres took part in this study; 83 patients (76 of them women) were evaluated. The radiation protocols were as follows: oral psoralen (8-methoxypsoralen; 0.6 mg/kg) was taken at each session; the starting dose of UVA radiation was determined according to skin type, with increments of 0.5 J/cm2 every 2 sessions. The subjects were randomized to receive 10-20 sessions 3 times per week. PUVA therapy was very effective: 68 patients (82%) reported total protection from BSLE. Four patients (5%) showed progress. Only 13% showed no improvement. The satisfactory results were not correlated with either the number of sessions or the J/cm2 of UVA. The intensity of tanning after the PUVA sessions did not appear to predict cure. Thirty-six percent of the patients had adverse reactions to treatment, including erythema, pruritus and triggering of BSLE. However, these effects only required the treatment to be stopped in 2% of the cases (for severe pruritus). The results in the various centres were similar.

Adolescent↗
PubMed1991

[Influence of retinoids on the bioavailability of methoxy-8-psoralen].

The retinoid-PUVA combination has been recognized as a satisfactory treatment of psoriasis. The absorption of 8-methoxypsoralen (8-MOP) is subject to wide interindividual variations under the influence of factors that are not yet known with certainty but are independent of age, sex and food taken at the same time as the psoralen. Whether concomitant retinoid administration influences the bioavailability of 8-MOP was considered an interesting question. The pharmacokinetics of 8-MOP were studied and compared in two populations of psoriatic patients: 119 patients treated with PUVA alone (psoralen-ultraviolet A) and 40 patients treated with the etretinate-PUVA combination (RePUVA). 8-MOP was assayed by the modified Ljunggren method 1 h, 1 h 30, 2 h, 2 h 30, 3 h and 4 h after ingestion of 8-MOP. The pharmacokinetic values recorded were: time and peak value of maximum plasma 8-MOP concentration (Tmax, Cmax) and area under the curve of time-related 8-MOP concentrations (AUC). The results obtained were as follows: Tmax PUVA 2 h 02 +/- 53 min RePUVA 1 h 56 +/- 50 min Cmax PUVA 159.12 +/- 88.85 ng/ml RePUVA 163.63 +/- 92.85 ng/ml AUC PUVA 343.33 +/- 211.06 ng*h/ml RePUVA 388.12 +/- 251.03 ng*h/ml Statistical analysis showed no significant difference in pharmacokinetic values between patients on PUVA alone and patients on RePUVA. Taking etretinate therefore does not alter the pharmacokinetics of 8-MOP and should not require any change in PUVA treatment.

Adolescent↗
PubMed1990

Seborrheic dermatitis and HIV infection. Qualitative analysis of skin surface lipids in men seropositive and seronegative for HIV.

We measured skin surface lipids (cholesterol, free fatty acids, triglycerides, wax esters, and squalene) in patients seropositive for human immunodeficiency virus (HIV) and those seronegative for HIV with and without seborrheic dermatitis. Cholesterol and wax ester fractions were similar in all four groups but triglycerides and squalene were significantly increased and free fatty acids significantly decreased in HIV-positive patients, regardless of the presence of seborrheic dermatitis. In addition, a strong negative correlation was found between free fatty acid and triglyceride levels. We conclude that abnormalities of skin surface lipids are not associated with the development of seborrheic dermatitis in HIV-positive persons but are associated with HIV infection itself.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Intra-uterine device failure: relation with drug use.

A case-control study was undertaken in order to test the relationship between commonly used anti-inflammatory agents and the efficacy of intra-uterine devices (IUDs). Women who had become pregnant while wearing an IUD were compared with non-pregnant IUD users. 717 cases and 717 controls were recruited from the same medical practices. The case-women (IUD failure) used anti-inflammatory drugs, particularly aspirin, more frequently than the controls (p less than 0.001). In contrast, oral progestins, taken in the second part of the cycle (16th to 25th day) were more frequently used by the control-women group (p less than 0.001). Although cases and controls differed in age and gravidity (younger and higher, respectively) standardization for these items did not change the findings for drug use.

Age Factors↗
PubMed1989

Low doses of zinc gluconate for inflammatory acne.

The effect of zinc on acne is unclear. In this study, only patients with an inflammatory acne were included in a double-blind trial using low doses of zinc gluconate (200 mg/day, corresponding to 30 mg zinc metal). We obtained a significantly different result between zinc and placebo groups in the inflammatory score (p less than 0.02). This efficiency could be explained by the action of zinc on inflammatory cells, especially granulocytes.

Acne Vulgaris↗