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Biomedical subjects

A Taïeb

Publications and source records attributed to A Taïeb.

At least 19 recordsLinked to original sources

Asymmetric periflexural exanthem of childhood: a clinical, pathologic, and epidemiologic prospective study.

OBJECTIVE: To assess the clinical, pathologic, and epidemiologic features of asymmetric periflexural exanthem of childhood (APEC), a clinically distinctive eruption, especially its link with pityriasis rosea and pattern of transmission. DESIGN: A prospective case series, including an analysis of epidemiologic triggering factors and mode of transmission. Pathologic study, including immunohistochemistry of the inflammatory infiltrate. SETTING: A mixed, community-based referral center. PATIENTS: A total of 37 girls and 30 boys with typical APEC referred from April 1994 to December 1996 were included in the study; 82% came from the greater Bordeaux area in France. INTERVENTION: None. MAIN OUTCOME MEASURE: Possible interhuman transmission of APEC. RESULTS: [corrected] No triggering factor was identified; no interhuman transmission occurred; and no demonstrable link with pityriasis rosea was apparent. Several new clinical variants were recognized or confirmed (high fever, facial and peripheral involvement, prolonged course). Distinctive perisudoral interface CD8+ infiltrate was suggestive of diagnosis. CONCLUSIONS: Interhuman transmission was doubtful, but inoculation disorder was still possible. Histopathologic findings seem more specific than previously thought.

Child, Preschool

Crusted (Norwegian) scabies induced by use of topical corticosteroids and treated successfully with ivermectin.

Crusted scabies is mainly observed in children with immunosuppression or mental illness. Treatment is very difficult, and relapse is frequent after topical scabicidal therapy. We describe a case of crusted scabies, induced by long-term application of a topical corticosteroid, relapsing after topical treatment and dramatically improved by ivermectin. We suggest that ivermectin is a safe and effective alternative therapy for the treatment of severe Sarcoptes scabiei infestation in children unresponsive to conventional treatment.

Administration, Topical

The relative expression of mutated XPB genes results in xeroderma pigmentosum/Cockayne's syndrome or trichothiodystrophy cellular phenotypes.

The human XPB DNA helicase is a subunit of the DNA repair/basal transcription factor TFIIH, involved in early steps of the nucleotide excision repair pathway. Two distinct clinical phenotypes, xeroderma pigmentosum associated with Cockayne's syndrome (XP/CS) and trichothiodystrophy (TTD), can be due to mutations in the XPB gene. In the present work, we studied cellular DNA repair properties of skin fibro-blasts from two patients mutated in the XPB gene: an XP/CS patient cell (XPCS2BA) with a T296C (F99S) transition and a TTD patient cell (TTD6VI) exhibiting an A355C (T119P) transversion. Both cells are clearly associated with different levels of alterations in their response to UV light. To establish the relationship between the relative expression level of these two alleles and DNA repair properties, we transfected SV40-transformed XPCS2BA (XPCS2BASV) cells with a plasmid (pTTD6VI) carrying the XPB-A355C cDNA and examined DNA repair properties after UV irradiation (cell survival, unscheduled DNA synthesis and kinetics of photoproduct removal) in stable transfectants. We isolated three clones, which express the XPB-A355C gene (Cl-5) or the XPB-T296C gene (Cl-14) or both genes (Cl-19). This con-stitutes a model system allowing us to correlate the relative expression levels of the XPB-A355C (TTD) and XPB-T296C (XP/CS) genes with various DNA repair properties. Overexpression of the XPB-A355C (TTD) gene in an XP/CS cell gives rise to a cellular phenotype of increased repair similar to that of TTD6VI cells, while equal expression of the two mutated genes leads to an intermediate cellular phenotype between XP/CS and TTD.

Cell Line, Transformed

Hypothesis: from epidermal barrier dysfunction to atopic disorders.

The rôle of a genetically-impaired epidermal barrier as the primary cause of the rapid increase in prevalence of atopic dermatitis and respiratory atopy is proposed, based on available clinical and experimental data. The subsequently increased exposure to irritants and allergen postnatally in predisposed individuals would lead in a subset of these to a specific TH2 cell activation favouring the development of IgE responses to atopens. Other routes of sensitization are probably important, but skin offers a good target to implement prevention strategies, so far completely ignored in the prophylactic recommendations given to high-risk families. Candidate genes for skin-barrier impairment are possibly those associated with ichthyosis vulgaris and X-linked hypohidrotic ectodermal dysplasia.

Dermatitis, Atopic

An ex vivo study of congenital pigmented nevi in epidermal reconstructs.

In order to study morphologic and functional characteristics of pigment cells in congenital pigmented nevi, autologous or heterologous reconstructs have been made using normal keratinocytes and nevus cells from the dermal-epidermal junction or from the dermis. All these cells, keratinocytes and nevus cells, were used as cell suspensions immediately after dissociation from the tissues or after subsequent brief cultivation in a serum-free medium. Reconstructed epidermis were cultured for 15 days at the air-liquid interface with or without ultraviolet (UV) B exposure. The reconstructs were examined macroscopically (formation of hyperpigmented macules), histologically (pigment cell nesting) and ultrastructurally (pigment structure and transfer). Typical nesting of nevus cells was observed in the dermal-epidermal junction or in the superficial dermis associated with macroscopically detectable small pigmented macules. UVB exposure induced an upward migration of nevus cells in the suprabasal layers of the epidermis. This tissue model can be considered as an excellent system for the ex vivo reproduction of pigmented nevi and as an assay of the sensitivity of nevus cells towards UVB irradiation.

Cells, Cultured

Sjögren-Larsson syndrome: early diagnosis, dietary management and biochemical studies in two cases.

BACKGROUND: Sjögren-Larsson syndrome (SLS) is a rare autosomal recessive disorder with worldwide distribution. It consists of ichthyosis, spastic diplegia and mental retardation caused by an enzymatic defect in fatty alcohol oxidation. OBJECTIVE: To study the effects of dietary management on clinical outcome and plasma/red blood cell fatty alcohol and plasmalogen concentrations. METHODS: To reduce fatty alcohol production, we reduced total fat intake to 30% of total intake of calories. To correct d 6 desaturase deficiency, we supplemented the diet with both n-3 and n-6 fatty acids to obtain a linoleic/linolenic acid ratio of 6 with low erucic acid rapeseed oil, plus high unsaturated fatty acids. We used gas liquid chromatography to assay blood cell membranes and plasma fatty alcohols/plasmalogens. RESULTS: Two SLS infants with proven fatty alcohol/NAD+ oxidoreductase deficiency were studied. Good clinical results were obtained in one of the patients when dietary intervention was started in early infancy and correlated well with plasma fatty alcohol decrease. However, no clinical improvement was seen in the other patient who started later with low compliance. Acitretin therapy was necessary to control skin symptoms in this second patient. CONCLUSION: Dietary intervention using the combined approach described here may improve fatty alcohol metabolism in SLS. However, only very early intervention seems clinically beneficial.

Alcohol Oxidoreductases

[Neonatal staphylococcal epidermolysis due to maternal-fetal transmission].

INTRODUCTION: The staphylococcal scalded skin syndrome (SSSS) is due to exfoliative toxins A or B excreted by some strains of Staphylococcus aureus. This syndrome is exceptional in the first hours of life. We report a case of SSSS due to materno-fetal infection. CASE REPORT: At 31 weeks of pregnancy a 40-year-old mother was febrile (39 degrees C) and a premature rupture of the amniotic sac occurred the following day. SSSS was diagnosed at 6 hours of life in the newborn, a 1760 g female. Staphylococcus aureus grew on the blood and vaginal bacterial cultures of the mother, as well as, from cultures of skin, nose, throat, and umbilical catheter in the newborn. The strains of Staphylococcus aureus isolated in the mother and the child had identical characteristic antibiotype and genotype by Random-PCR. The genes for both exfoliations A and B were present. Epidermization was rapidly obtained and no septicemia or septic complication was noted. DISCUSSION: Staphylococcus aureus is usually responsible for nosocomial infections which occur in the early newborn period. In most cases, the infection is transmitted by a carrier who manipulates the child (family, visitors, nurse or medical staff). In our case, onset of SSSS early after birth suggested a perinatal transmission, due to lower genital tract infection in the mother. The presence of SSSS in the child and not in the mother may be explained by a massive perinatal infection and low elimination of the toxin in the newborn resulting in higher concentrations of exfoliative toxins in the blood.

Adult

Acute urticaria in infancy and early childhood: a prospective study.

OBJECTIVES: To establish the clinical, etiological, and prognostic features of acute urticaria in infancy and early childhood and to define its optimal management. DESIGN: Prospective study. The inception cohort was collected from April 1, 1992, through March 31, 1994. After initial evaluation, the course of the disease was assessed at 2 months and after 1 to 2 years. SETTING: Emergency department of a regional teaching pediatric hospital (referral center), which is also the only pediatric hospital for the general community in the city (population, 600,000 inhabitants). PATIENTS: Fifty-seven consecutive infants, aged 1 to 36 months, hospitalized with a final diagnosis of acute urticaria. Follow-up at 1 to 2 years was available in 40 of 57 patients. INTERVENTION: Oral antihistamines (dexchlorpheniramine maleate, terfenadine, or hydroxyzine hydrochloride) for 2 weeks. MAIN OUTCOME MEASURES: Recurrence and chronicity. RESULTS: Annular or geographic papules and plaques with hemorrhagic lesions were seen in 28 patients (49% of cases) and angioedema in 34 patients (60% of cases). An underlying cause was suspected or identified in 52 patients (91% of cases). Infection, either associated or not with drug intake, was the cause in 46 patients (81%) and foods were the cause in 6 (11%). Parasitic infestations were noncontributory. Hemorrhagic lesions and association with articular symptoms were statistically more frequent in urticaria caused by infections. Atopy in the patient or family was associated in 33 patients (58% of cases), and particularly atopic dermatitis was associated with urticaria caused by food. At 1- to 2-year follow-up, 12 (30%) of 40 patients surveyed had chronic or recurrent urticaria. CONCLUSIONS: Causative factors in urticaria are dominated by benign viral illnesses, often associated with antibiotic drug therapy. In most patients, laboratory investigations are not required. Twenty percent to 30% of cases evolve into chronic or recurrent disease.

Acute Disease

Congenital cutaneous defects as complications in surviving co-twins. Aplasia cutis congenita and neonatal volkmann ischemic contracture of the forearm.

BACKGROUND: During twin pregnancies, several complications may result in the death of a co-twin depending on the date of death. We describe herein 2 infant survivors of monozygotic twin pairs with 2 distinct possible complications: a aplasia cutis congenita and Volkmann ischemic contracture. OBSERVATIONS: One infant had extensive aplasia cutis congenita with an associated monozygotic co-twin who died at 3 months of gestation, and the other child had a localized arm defect due to Volkmann ischemic contracture and brain damage, with a co-twin who died at approximately 6 weeks of gestation. CONCLUSIONS: Congenital cutaneous defects may result in the death of a co-twin. The most common of these defects is aplasia cutis congenita associated with a fetus papyraceus or a dead fetus related to ischemic/thrombotic events in the placenta and fetus. Volkmann ischemic contracture is rare in the newborn but can cause neonatal cutaneous defects. The cause of Volkmann ischemic contracture in newborns is unknown; however, our second observation suggests the possible role of a dead fetus.

Compartment Syndromes

[Linear and whorled nevoid hypermelanosis: report of two cases].

CASE REPORTS: Two cases of linear and whorled nevoid hypermelanosis are reported. Cutaneous lesions (hyperpigmented macules along Blaschko's lines) appeared gradually after birth. Neurologic anomalies were detected in both cases (symptomatic in one, only cerebral MRI anomalies in the other). CONCLUSION: This sporadic condition, probably caused by somatic mosaicism, must be differentiated from incontinentia pigmenti, Mac Cune-Albright disease and chimerism. Its situation among the Blaschko linear pigmentary anomalies (hypomelanosis of Ito) is discussed.

Brain

Chimeric human epidermal reconstructs to study the role of melanocytes and keratinocytes in pigmentation and photoprotection.

Chimeric epidermal reconstructs made with Negroid melanocytes and Caucasoid keratinocytes (or vice versa) were studied before and after UVB irradiation to understand the respective roles of these cells in tanning and photoprotection, especially lipoperoxidation and enzymatic defences against free radicals. Using this approach, we have confirmed overall the theory of the epidermal melanin unit. We have also shown that melanocytes of poorly tanning Caucasoids, which have a comparatively higher content of unsaturated fatty acids in their cell membrane, are more prone to the peroxidative effects of UV light, and that keratinocytes participate in photoprotection via phototype-dependent antioxidant enzyme activities, especially for catalase.

Adult

Quantification of eumelanin and pheomelanin: stereologic image analysis method.

OBJECTIVE: To develop an ultrastructural stereologic image analysis method allowing quantification of intracellular melanization. STUDY DESIGN: First, in the field of image analysis, a newly elaborated segmentation method, SEM2, was compared with a previously described method based on gray level histograms. Only SEM2 allows the segmentation of melanin in micrographs of poorly melanized melanocytes. Second, in the field of stereology, estimation of cell volume remains problematic in the case of mixed cell populations. This problem is approached by the comparison of stereologic alternatives and cytochemistry (L-3, 4-dihydroxyphenylalanine reaction) in epidermal melanocytes and melanoma cells from several in vitro experiments. The cytochemical approach was found to be the best choice. RESULTS: Concerning the quantification of eumelanin and pheomelanin, the alkali elution method, permitting the specific dissolution of pheomelanin on ultrathin sections, was validated in normal human follicular melanocytes. CONCLUSION: These results allow us to envisage the stereologic quantification of eumelanin and pheomelanin at the ultrastructural level. At present our method is undergoing evaluation by comparison with the present method of reference based on high-performance liquid chromatography.

Adolescent

[Severe hemangiomas treated with interferon alpha-2b: seven cases].

INTRODUCTION: High-dose corticosteroids are the primary means of controlling alarming hemangiomas. However, only 2/3 of these life-threatening hemangiomas regress or are stabilized with corticosteroids: and for others there is no regularly safe and effective treatment. Contradictory publications have been reported about the efficacy of interferon (INF) alpha in hemangiomas, we report our experience concerning the management of 7 cases. PATIENTS AND METHODS: Seven infants have been treated with INF alpha-2b in our Pediatric Dermatology Unit. All hemangiomas were corticosteroid resistant. Hemangiomas were located on head and neck in 6 cases and on lower limb in one case in association with platelet trapping syndrome. Mean age at beginning of treatment was 7.5 months and mean duration of treatment was 5 months. INF alpha-2b was given daily in subcutaneous injections of 3 millions units per square meter of body surface area. RESULTS: After one month of treatment, 2 cases of facial hemangiomas showed a dramatic improvement, and INF alpha-2b was maintained for one year. One case was stabilized, but INF was ineffective in 3 cases after 2 months of treatment (the child with platelet trapping syndrome died at 4 months of age). The treatment had to be stopped in one case because of hepatitis. No long term side effects were noted with a mean follow-up of 27 months. CONCLUSION: INF alpha can be an interesting alternative therapy for infantile hemangiomas. However, only a minority of patients can be considered as excellent responders at current dosages and long term secondary effects cannot be excluded.

Anti-Inflammatory Agents