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Biomedical subjects

M Jeanmougin

Publications and source records attributed to M Jeanmougin.

At least 37 records · Page 2Linked to original sources

Phototoxic properties of perfumes containing bergamot oil on human skin: photoprotective effect of UVA and UVB sunscreens.

As part of an international cooperative study of the photophysical, photomutagenic and photocarcinogenic properties of bergamot oil and the effect of UVA and UVB sunscreens, the phototoxic properties of model perfumes containing 5, 15 and 50 ppm 5-methoxypsoralen (5-MOP) in bergamot oil with and without a sunscreen have been investigated on human skin. It has been confirmed that the photosensitivity of human skin is maximal 2 h after perfume application. Interestingly the addition of a UVA sunscreen is more efficient for decreasing the phototoxic properties of bergamot oil than is a UVB sunscreen. The addition of sunscreens in a model perfume containing 50 ppm 5-MOP in bergamot oil can reduce the phototoxic properties of this perfume to a toxicity equivalent to that produced by the application of a model perfume containing 15 ppm 5-MOP without sunscreens. However, despite their promising protective effect in vitro, UVB and UVA sunscreens at low concentration (0.5%-1%) in perfumes cannot suppress the phototoxicity of bergamot oil on human skin.

Adult↗

[Treatment of solar urticaria: advantage of terfenadine].

Solar urticaria is a rare photodermatosis, but it is extremely incapacitating and therapy is usually ineffective. Three patients who took a daily dose of 240 mg terfenadine were able to be normally exposed to sunlight. This efficacy was confirmed by photobiological tests. The minimal dose necessary to induce urticaria was increased at least three times. These results confirming recently published ones. Terfenadine at 240 mg per day seems to be the treatment of choice for solar urticaria because of its efficacy and excellent tolerance-especially as there is no sedative effect.

Adult↗

Prediction of benzoyl peroxide phototoxicity by photoepidermotests after repeated applications. Preventive value of a UVB filter.

The predictive phototoxicity test known as photoepidermotest consists of twice daily applications of the product tested for 16 days, followed by total spectrum irradiation with a 2,500-W Xenon lamp in infraerythema and supraerythema doses. Phototoxicity is revealed by an erythema with the infraerythema dose and/or by accentuation of the erythema provoked by the supraerythema dose when compared with the "irradiation only" (i.e., no product) control skin area. This technique, used in a controlled, double-blind trial, showed that a 10% benzoyl peroxide (BPO) gel was phototoxic in eight out of 18 subjects tested (44%). It also showed that adding a UVB filter (phenylbenzimidazole sulfonic acid 1%) to the BPO preparation was effective in preventing phototoxic reactions in seven of these eight subjects.

Adult↗

[Occupational eczema with photosensitivity caused by contact with Bryozoa].

Contact eczema to Bryozoa is a very invalidating fishermen's disease. Described in the North Sea ("Dogger Bank itch") and in the eastern Channel, it begins with the hands which have touched Bryozoa, these being microscopic "moss-like animals", unrelated to algae, which form coralliform, encrusting and filamentous colonies attached to the sea-floor. Sensitization results from handling nets (drag-nets and trammels) or, less frequently, fish trays. Bryozoa responsible for the disease are Alcyonidum hirsutum and, mostly, Alcyonidum gelatinosum. The case of occupational eczema presented here discloses two hitherto unrecognized allergens: another Bryozoa species, Electra pilosa, which proliferates in the early summer and forms encrusting colonies on various supports, and a sea-weed, Sargassum muticum, which up to now had not been held responsible for skin lesions. The summer outbreaks, from May to September, and the fact that the face and upper chest are involved are classically ascribed to the natural cycle of Bryozoa (colonies multiply in the warm season and regress in the winter) and to contact with uncovered parts of the body. The results of our photobiological exploration suggest that the distribution of the eczema might well be due to an additional photoallergic reaction.

Bryozoa↗

[Photosensitization after intramuscular injections of hematoporphyrin. 3 cases].

Haematoporphyrin is a synthetic porphyrin the photosensitizing properties of which are used for the detection and treatment of some neoplasias. Three cases of phototoxicity from Hemedonine, an "anti-asthenia" drug composed of pure haematoporphyrin, are reported. Following exposure to the sun, painful urticarial plaques developed at the sites of intramuscular injections, and spread to the lumbar and abdominal regions, leaving a brownish pigmentation which persisted for years. Photobiological exploration was performed in one of these patients, demonstrating photosensitivity to Hemedonine in vivo and showing that long UVA rays were essentially responsible for the lesions. Histological examination elicited the initial vascular changes of a phototoxic reaction and suggested a new mechanism of photosensitization: "photo-induced immune vasculitis". The phototoxic effects of haematoporphyrin are primarily due to the destruction of intracellular organelles consecutive to oxidative denaturation of membrane systems. The initial phase of the phototoxic reaction might consist of complement activation and degranulation of dermal mast cells.

Adult↗

[Dosimetry of solar ultraviolet radiation. Daily and monthly changes in Paris].

The intensity of ultraviolet A and B radiations was measured in Paris (48 degrees North) by means of silicon photoelectric cells (Osram Centra dosimeter) from December, 1984 till February, 1986. The results, which must be regarded as approximate, are expressed as physical units (mW/cm2) and biological units (minimal erythema dose/hour). For sunny days two curves are presented separately for UVB and UVA: daily variations in radiation (hourly measurements) and daily variations at 11 hours (solar time) during one year. Maximum irradiation was observed at noon in early July: UVB 0.15 mW/cm2, UVA 5.4 mW/cm2. Between December and July the amount of UVB radiation was multiplied by 14 and that of UVA radiation by 9. For subjects with clear photo-type and when the sun was at its zenith, an MED per hour was obtained from May 1 onwards. Within a day, 30 p. 100 (summer) and 50 p. 100 (winter) of erythema-producing UV intensity were delivered between 11 and 13 hours (solar time). This kind of study has numerous clinical applications: advice regarding exposure to sun rays, dosing of heliotherapy, epidemiological data concerning photodermatitis (circumstances of exposure, UV threshold dose) and photocarcinogenesis (determination of annual MED doses in relation to areas of uncovered skin and occupational exposure to sun rays). Other studies on the French territory will provide a map of UV irradiation.

Paris↗

[Photosensitivity in human pathology: mechanisms and clinical aspects].

Photosensitivity diseases are reviewed. The pathogenesis of photodermatoses is not completely elucidated, especially because the photosensitizing agents are rarely identified. In exogenous photosensitization, the chemical agent (chromophore) is most often identified, reaching the skin either via topical contact or by systemic administration (drugs). Concepts of phototoxicity (photochemical reaction) and photo-allergy (photo-immunologic reaction) explain the clinical aspects. Dermatoses with photosensitivity are divided into three groups: photo-aggravated dermatoses (solar herpes, lupus erythematosus), photosensitivity caused by protective system defect (xeroderma pigmentosum), and photosensitivity caused by metabolic defects (porphyrias, pellagra). Idiopathic photodermatoses (unknown chromophore) are triggered by solar exposure (systemic photo-allergens would serve as mediators): 'benign estival polymorphous light eruption', polymorphous light eruptions, persistent light reactor, solar urticaria.

Adult↗