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Biomedical subjects

L Dubertret

Publications and source records attributed to L Dubertret.

At least 19 recordsLinked to original sources

[Methotrexate-induced skin detachment].

The undesirable effects of high-dose methotrexate on integument and mucosa are well-known, but lesions of the skin proper, characterized by distal erythema with desquamation, are rare. We report the case of a male patient presenting with extensive skin erosions after intravenous infusion of a 5 gram total dose of methotrexate to treat high-grade lymphoma. The skin disease was accompanied by renal, hepatic and mucosal lesions, as well as bone marrow aplasia. The mechanism of cutaneous necrosis is uncertain, but it might be due to direct toxicity of methotrexate to the epidermis. The patient was also treated with G-CSF. He recovered from aplasia within 6 days, without infectious complications. Haematopoietic growth factors might have reduced the risk of infection arising from the skin, by shortening the duration of cytopenia.

Acute Kidney Injury

Leukotriene B4 and platelet-activating factor in human skin.

Acute inflammatory reactions are characterized by leukocyte infiltration associated with increases in vascular permeability and in local blood flow. Leukocyte infiltration can be induced by chemotactic factors such as leukotriene B4 (LTB4) and paf-acether (formerly known as platelet-activating factor) that can be generated within inflammatory lesions. Vascular permeability and increase in blood flow are also affected by LTB4 and paf-acether, as well as by several other substances, including histamine and prostaglandins. Derived from arachidonic acid via the 5 lipo-oxygenase pathway, LTB4 is one of the most potent leukocyte chemotactic substances known. Intradermal injections of LTB4 induce dermal neutrophil infiltration in animal models and in humans. Topical application of LTB4 to human skin induces intraepidermal micro-abscesses containing numerous intact neutrophils. LTB4 has been found to be increased in psoriatic lesions, but its synthesis by epidermal cells remains undecided. Like other leukotrienes, LTB4 can stimulate DNA synthesis in cultured human epidermal keratinocytes. However, receptors for LTC4 but not for LTB4 have been found on human keratinocytes in culture. Paf-acether is an ether-linked phospholipid identified as 1-O-alkyl-2-O-acetyl-sn-glycero-3-phosphocholine and is considered to be one of the most potent mediators of acute allergic and inflammatory reactions. For instance, intradermal injection of paf-acether induces inflammatory events such as neutrophil infiltration and increase in vascular permeability. Recent data suggest that cutaneous cells, such as fibroblasts and keratinocytes, are capable of producing paf and that paf is released during the development of allergic cutaneous reactions.(ABSTRACT TRUNCATED AT 250 WORDS)

Dermatitis

MR imaging of breast hemangioma in female infants.

Breast hemangioma in female infants is a rare benign lesion, prone to spontaneous regression. But when the lesion regresses there is a risk of breast atrophy if the breast bud is included in or very close to the hemangioma. A trial of corticosteroid therapy could be proposed to prevent this risk, but one must be sure that the breast bud is included in or very close to the hemangioma before treatment. We studied 4 children with breast hemangioma to evaluate the ability of MR Imaging in the diagnosis of breast bud inclusion. 0.5 Tesla axial Spin Echo T2-weighted images (TR = 2000 ms; TE = 120 ms) clearly depicted interface between high signal appearance of hemangioma and hypo-intensity of the breast bud: in our four patients we were able to determine whether or not the hemangioma involved the breast bud. Our preliminary study seems to demonstrate that MR imaging is a valuable imaging technique to determine which patients could be eligible for a trial of corticosteroid therapy.

Breast Neoplasms

Efficacy and safety of calcipotriol (MC 903) ointment in psoriasis vulgaris. A randomized, double-blind, right/left comparative, vehicle-controlled study.

BACKGROUND: The biologically active form of vitamin D3, calcitriol, may offer a new therapeutic approach to psoriasis. Calcipotriol, a new vitamin D3 analogue, is at least 100 times less calcemic than calcitriol. OBJECTIVE: Our purpose was to study the efficacy and safety of calcipotriol in the treatment of psoriasis vulgaris. METHODS: In a right/left comparative, double-blind study, treatment with calcipotriol ointment (50 micrograms/gm) twice daily and placebo was given for 4 weeks. The preferred treatment was continued, without opening the code, for another 4 weeks. Efficacy, as measured by the Psoriasis Area and Severity Index and by the investigator's and patient's global assessment, and safety were assessed every 2 weeks. RESULTS: The mean Psoriasis Area and Severity Index fell in 4 weeks from 14.2 to 6.3 with calcipotriol and from 14.1 to 9.2 with placebo (p < 0.001; 95% confidence interval for difference: 1.78-->3.94). Local side effects were equally common with calcipotriol and placebo. The mean serum calcium remained unchanged. CONCLUSION: Topical application of up to 50 gm of calcipotriol ointment per week was found to be an effective and safe treatment of psoriasis vulgaris.

Adult

Photosensitization by Photofrin II delivered to WI26VA4 SV40-transformed human fibroblasts by low density lipoproteins: inhibition of lipid synthesis and fatty acid uptake.

Irradiation with 365 nm light of Wi26VA4 SV40-transformed human fibroblasts cultured for 24 h in the presence of low density lipoproteins loaded with the anticancer porphyrin mixture Photofrin II resulted in a near complete inhibition of [14C]oleic acid incorporation into triacylglycerols, cholesteryl esters and phospholipids. More than 80% reduction of the fatty acid incorporation in all lipid classes was observed following an irradiation dose of 1 J/cm2. The activities of the respective acyltransferases, measured in vitro on cell homogenates, were also markedly diminished, but to a lesser extent than lipid synthesis from oleic acid. Moreover, oleic acid uptake by cells was strongly and rapidly reduced. It is suggested that the rapid inhibition of membrane phospholipid synthesis upon cell photosensitization, due to both a direct inactivation of acyltransferases and to a reduction of fatty acid utilization, could play an important role in the photocytotoxic effect of Photofrin II.

Cell Line, Transformed

Acral persistent papular mucinosis and IgA monoclonal gammopathy: report of a case.

The case of a 60-year-old man with acral persistent papular mucinosis (APPM), thought to represent a new distinctive form of dermal mucinosis not associated with systemic diseases, is reported. The patient had a 4-year history of multiple small papular lesions on the distal forearms, wrists and back of the hands. Histologically, mucin deposits in the upper and mid dermis sparing a superficial subepidermal grenz zone were observed. In contrast to previously described cases, a monoclonal IgA of kappa light chain isotype was detected. Our findings challenge the view that absence of paraproteinemia is a peculiar characteristic of APPM and raise once more the question of its relationship to the discrete papular form of lichen myxedematosus.

Diagnosis, Differential

Keratosis follicularis spinulosa decalvans: report of a case with ultrastructural study and unsuccessful trial of retinoids.

Keratosis follicularis spinulosa decalvans (KFSD) is a genetic disorder characterized by disseminated follicular hyperkeratosis, especially localizated to scalp and face. We report the case of a new patient displaying typical features of KFSD. Ultrastructural study was performed and displayed round keratohyalin granules in follicular keratinocytes. Trial with etretinate, which has not been reported before in this disease, proved to be ineffective.

Biopsy

Genetic linkage of recessive dystrophic epidermolysis bullosa to the type VII collagen gene.

Generalized mutilating recessive dystrophic epidermolysis bullosa (RDEB) is characterized by extreme skin fragility owing to loss of dermal-epidermal adherence. Immunohistochemical studies have implicated type VII collagen, the major component of anchoring fibrils, in the etiology of RDEB. In this study, we demonstrate genetic linkage of the type VII collagen gene and the generalized mutilating RDEB phenotype. We first identified a Pvull polymorphic site by digestion of an amplified product of the type VII collagen gene, which was shown to reside within the coding region. Genetic linkage analysis between this marker and the RDEB phenotype in 19 affected families which were informative for this polymorphism showed no recombination events, and gave a maximum lod score of 3.97 at a recombination fraction (theta) of 0, demonstrating that this DNA region is involved in this form of RDEB. These data provide strong evidence that the type VII collagen gene, which has also been linked with the dominant form of the disease, harbors the mutation(s) causing the generalized mutilating form of RDEB in these families, thus underscoring the major functional importance of type VII collagen in basement membrane zone stability.

Base Sequence