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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↗
PubMed1995

[Candida vasculitis].

Apart from direct skin attacks, yeasts of the Candida group hold a place that is much discussed in the occurrence of immuno-allergic reactions of the skin, because of their usual saprophytic characteristics. We report here on observation of a patient of 62 years who presented with a secondary purpuric maculo-papular eruption making a tri-symptom of Gougerot, for which we have incriminated the role of the immunogenicity of Candida. Skin histology confirmed the presence of an angiitis and necrotising capillarity. An intradermal test with candidine reproduced the skin symptoms and histology, whilst other microbial and fungal tests remained within normal limits. Other examinations showed the transitory presence of circulating immune complexes, although the remainder of the immunity factors were negative. A digestive focus of Candida was present. Recovery occurred after systemic mycological treatment was started, though there was a return of symptoms after a temporary initial check.

Amphotericin B↗
PubMed1994

Clinical evaluation of topical isotretinoin in the treatment of actinic keratoses.

BACKGROUND: Retinoids have been shown to improve the manifestations of skin photodamage, including actinic keratoses. OBJECTIVE: The efficacy and tolerability of isotretinoin 0.1% cream in the treatment of actinic keratoses were evaluated in a randomized, double-blind, placebo-controlled, parallel-group study. METHODS: One hundred patients were randomly assigned to treatment with 0.1% cream or vehicle twice daily for 24 weeks to the face, the scalp, and the upper extremities. Patients were assessed every 4 weeks by the investigators, who counted and recorded the number of lesions in each treatment area. The 93 patients who had at least one postbaseline assessment were included for efficacy analysis. Local tolerability was evaluated at each study visit. RESULTS: On the face, the reduction in number of actinic keratoses (mean +/- SEM) at the end of treatment was greater for patients treated with isotretinoin (3.9 +/- 0.6, i.e., 66% of patients with a reduction > 30%) than with placebo (1.7 +/- 0.5, i.e., 45% of patients with a reduction > 30%); this difference was statistically significant (p = 0.001). No significant drug effect was seen for lesions on the scalp or upper extremities. Mild to moderate local reactions with isotretinoin abated with reduced treatment frequency. CONCLUSION: Our results suggest that isotretinoin 0.1% cream cannot compete with more rapid treatments of actinic keratoses. However, its effect on facial lesions may be beneficial during long-term treatment of associated sun-damaged skin.

Administration, Topical↗
PubMed1994

A novel therapeutic approach to psoriasis with combination calcipotriol ointment and very low-dose cyclosporine: results of a multicenter placebo-controlled study.

BACKGROUND: Recent advances in the treatment of psoriasis include both the topical vitamin D analogue calcipotriol and cyclosporine. Combined treatments have been sought to decrease the incidence of side effects while maintaining efficacy in the treatment of severe chronic plaque psoriasis. OBJECTIVE: The objective of this study was to evaluate the efficacy and safety of the combination of 2 mg/kg/day of cyclosporine with calcipotriol ointment (50 micrograms/gm) in the treatment of severe plaque psoriasis. METHODS: Sixty-nine patients were randomly selected for this double-blind, multicenter study to receive cyclosporine (2 mg/kg/day) combined with calcipotriol ointment (50 micrograms/gm) or cyclosporine (2 mg/kg/day) combined with placebo ointment (vehicle of calcipotriol) for a 6-week period. RESULTS: Complete clearing or 90% improvement in Psoriasis Area and Severity Index score occurred in 50.0% of patients in the calcipotriol/cyclosporine group in comparison with 11.8% of patients treated with placebo/cyclosporine (p = 0.0019). The confidence interval for the difference ranged from 17.8% to 58.7%. No difference was found between the two groups with respect to side effects. CONCLUSION: The calcipotriol/cyclosporine combination was more effective than placebo/cyclosporine. Further studies are needed to establish the long-term efficacy and safety profile of this combination therapy.

Adult↗
PubMed1994

Determination of 8-methoxypsoralen kinetics: a relevant factor in the treatment of psoriasis by psoralen plus ultraviolet A therapy.

We compared the efficacy of psoralen plus ultraviolet A (UVA) therapy in 2 groups of psoriatic patients: a group of patients treated by a protocol adapted to the results of 8-methoxypsoralen (8-MOP) plasma kinetics (kinetics group) versus a control group of patients treated according to Pathak's standard protocol (UVA exposure 2 h after oral administration of a dose of 8-MOP equal to 0.6 mg/kg) (control group). The 8-MOP plasma kinetics were determined before the beginning of treatment. The parameter for comparison is the rapidity of clearing, taking into account the number of UVA exposures and UVA joules received. The analysis of the results observed show a 26.6% decrease in the number of UVA exposures and a 38.4% decrease in the dose of UVA received. These results are confirmed by the individual analysis of the rapidity with which the clearance of psoriatic lesions was obtained in patients who were treated with the standard PUVA protocol during the first attack and with the adapted protocol during the second attack.

Adolescent↗
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↗
PubMed1993

Protective effect of selenium and zinc on UV-A damage in human skin fibroblasts.

Ultraviolet A radiation participates in cytotoxicity and carcinogenesis of the skin by a mechanism involving the generation of reactive oxygen species. Endogenous antiradical defense systems utilize metalloenzymes including Se-dependent glutathione peroxidase and Cu and Zn superoxide dismutase. The aim of the present work was to determine the protective effect of two trace elements, Se and Zn, on cultured human diploid fibroblasts exposed to UV-A radiation (broad-spectrum source with a maximum intensity at 375 nm). Selenium in the culture medium (0.1 mg/L) in the form of sodium selenite increased the synthesis and activity of glutathione peroxidase by 60.5% in the absence of exposure to UV-A radiation and by 35% after irradiation with 5 J/cm2 (P = 0.043). The presence of this element significantly increased the survival of UV-A-irradiated fibroblasts (P < 0.0001). This confirms the essential role of Se in the detoxifying activity of the enzyme. In addition, thiobarbituric acid-reacting substances (TBAR), which are lipid peroxidation markers, decreased in the presence of exogenous Se: -19% and -22% without irradiation and after irradiation with 5 J/cm2 (P = 0.056). When Zn was added at the dose of 6.5 mg/L as ZnCl2, fibroblasts subjected to oxidizing stress induced by UV-A were protected from cytotoxicity (P < 0.0001). The TBAR production decreased significantly: -33% without irradiation and -34% after irradiation with 5 J/cm2 (P = 0.008). Superoxide dismutase activity, however, decreased after supplementing with Zn: -26% without irradiation and -20% after UV-A irradiation (P = 0.017). The antioxidant properties of Zn are thus apparently independent of superoxide dismutase activity.

Cell Division↗
PubMed1993

[Plasma levels of psoralens after celery ingestion].

Psoralens are photosensitizing substances present in many vegetables, some of which are routinely consumed. These vegetables are responsible for contact phytophotodermatitis, but it was agreed that they did not produce photodermatitis when taken orally. Ljunggren has recently questioned this concept by reporting a case of phototoxic accident which occurred after ingestion of 450 grams of celery roots (Apium graveolens). In a study in healthy volunteers we looked for psoralens in blood and analyzed the cutaneous photosensitivity by the minimal phototoxic doses (MPD) method, after ingestion of celery in large amounts (500 grams and more). Plasma concentrations of psoralens were inexistant in all subjects and at all sampling times, and no phototoxic reaction was detected by MPD. Celery roots, therefore, do not seem to be photosensitizing, even after ingestion in large amounts, but they might increase the risk of phototoxicity in PUVA-therapy. The same applies to fennel and parsnip.

Adult↗
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↗