Biomedical subjects
Publications and source records attributed to N Claessens.
The physiological responses to ultraviolet light exposure can be immediate, early or delayed. Typical examples include actinic erythema, suntan, the telogen actinic effluvium, ephelids, lentigines, some melanocytic naevi, and actinic wrinkles.
There exists a series of photodermatoses due to phototoxic or photoallergic reactions. Anamnestic and clinical clues supplemented by dermatopathological examination and photobiological tests are key features for reaching the correct diagnosis and the adequate choice of therapy.
Oral administration of lithium is used as treatment in psychiatry. The drug frequently induces cutaneous side effects corresponding to acneiform or maculo-papular eruptions, psoriasis and folliculitis. Men are more frequently affected than women. These manifestations are characterized by the accumulation of neutrophils in the skin. Alopecia and classical drug reactions are also possible. Topical applications of lithium used to treat some dermatoses do not induce similar side effects, probably because dosages are much lower.
A presumed melanoma metastasis is sometimes found without any evidence for the primary neoplasm. Such an orphan metastasis merits a complementary exploration. Searching for the primary melanoma must then be performed using non invasive and clinically oriented methods. Beside a thorough skin examination, otorhinolaryngological, ophtalmic and gynecologic searches are recommended. In addition, paraclinical investigations are conducted according to the metastatic location, the gender and the functional complaints of the patient. The prognosis of these orphan metastases is not more dramatic than when the primary lesion is identified. Therapies are similar to those proposed in the classical presentation of the disease.
Some cutaneous functions of importance are governed by periodical variations according to the nycthemeral timing. Similarly to other organs, the skin is under the influence of a coherent organisation of circadian and nythemeral rhythms modulating various biological cycles which usually display a wide amplitude. The cutaneous biorhythms in humans suggest that during daylight the skin boosts diverse protective functions with regard to environmental threats. In the evening and at night, the skin increases its renewal and diverse metabolic processes. Biorhythms in the skin which are in line with the organism's needs, merit to be recognized. Chronophysiology, chronopathology and clinical chronopharmacology may help reach optimal therapeutic decisions.
BACKGROUND: Human papilloma viruses (HPV) are responsible for a variety of proliferative epithelial lesions including anogenital condylomas. These lesions may regress during treatment with an immune-response modifier such as imiquimod. The release of specific cytokines from the monocyte-macrophage lineage induces a cascade of events abating the HPV replication. METHOD: A total of 14 persistent warty anogenital lesions were excised 4 to 7 weeks after completing a 4-month imiquimod treatment. Another series of 25 untreated condylomas and 8 bowenoid papulosis served as controls. All examined lesions had been excised in otherwise healthy individuals with a normal immune status. Lesions were examined for the presence of Langerhans cells and subpopulations of the monocyte/macrophage/dendrocyte lineage using immunohistochemical detection of L1-protein, CD68, lysozyme and Factor-XIIIa. CD45R0-positive T lymphocytes were also identified. HPV capsid antigens and genotypes were searched for using immunohistochemistry and in situ hybridization, respectively. RESULTS: The persistent although treated anogenital lesions were identified as 10 viral condylomas, 3 bowenoid papulosis and 1 basal cell carcinoma. The inflammatory cell densities and distributions were similar in the untreated and imiquimod-resistant condylomas with the exception of Factor XIIIa-positive dendrocytes. These dermal dendritic cells were slim and rare in all imiquimod-resistant lesions. In contrast, about two-thirds of the untreated condylomas were enriched in these cells. CONCLUSION: As dermal dendritic cells play a role in the immune surveillance, their low densities in some lesions might be a key feature responsible for low cytokine local production and failure of imiquimod treatment. The combined apparent lack of Langerhans cell activation might suggest that both intraepidermal and intradermal compartments of antigen-presenting cells are affected in imiquimod-resistant lesions.
Several compounds listed as illicit doping agents can express some effects on the skin. The cutaneous signs are diverse. The clue of the intake of such compounds can be supported by objective non-invasive biometrological assessments. However, such evaluations do not bring the irrefutable proof. The skin can also present unwanted reactions indicating intolerance to the doping agent. Such physiopathological manifestations are not limited to the sport competition, but can also affect some groups of the population searching for a look reminiscent of the ideal young and performing athlete.
The frequent practice of a music instrument represents a risk for frictional or allergic contact dermatitis. The localisation and type of lesions are often typical for the musician specialty.
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Skin ageing is the global result of the influence of numerous factors. Oxidative stress through the intervention of free radicals is one of the most important biological mechanisms solicited by ageing promotors. Prevention of skin senescence relies on several approaches. The main ones are sun protection, tobacco avoidance and limitation of sustained mechanical stress to the skin. Free radical scavengers in adequate combinations might slow down the ageing process. In cosmetology, retinol fulfills its claims. Vitamins E and C, as well as selenium and some plant extracts also show some interest. In the search for increased efficacy, tretinoin is the single topical drug available. Its biologic activity boosts the epidermal growth and the collagen synthesis while inhibiting some metalloproteinases responsible for dermal degradation. Clinical proofs of its efficacy are beyond doubt.
Metastases to the eyelids are rare. They may appear as diffuse swellings, nodules or ulcerations. Most often they correspond to the dissemination of a breast adenocarcinoma. An 83 year old woman is reported with mammary adenocarcinoma metastasizing to the eyelids.
Bites by terrestrial vertebrates, reptiles or mammals, represent a special risk in tropical regions. Envenomation is possible by a few lizards and many snakes. For mammals, tissular destructions due to the bite can be severe. Whatever is the offending animal, bites can further become infected by transmitted viruses or bacteria.
Among the diverse endoparasitic disorders some are primary cutaneous disorders and others exhibit signs on the skin in association with predominant internal manifestations. A variety of protozoans and helminths are responsible for these disorders.
Burning mouth is a symptom typical for the oral mucosa. In contrast, pruritus is absent at this site. The situation which is the reverse on the skin can be explained by microanatomical differences in the sensorial innervation and by a different balance between neuromediators. Burning mouth sensation calls for the search of a series of diseases. However, it is most often a monosymptomatic expression of a minimal lichenoid stomatitis.
The treatment of moderate to severe acne often relies on antibiotherapy in order to eradicate as much as possible microorganisms such as Propionibacterium spp colonizing the sebaceous follicles. In recent years, bacterial resistances against specific antibiotics have emerged. Both the antibiotic and its administration modalities must be considered in order to control the risk. With regard to this conundrum, minocycline is a medication of choice among the diverse anti-acneic therapies.
We report a 29-year-old pregnant woman who developed toxic epidermal necrolysis at 29 weeks of gestation after administration of ritodrine, indomethacin and betamethasone. Toxic epidermal necrolysis is an unreported side effect of this widely used combination of medications. Since toxic epidermal necrolysis is a potentially fatal disease, awareness of a possible association is warranted.