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Biomedical subjects

A Ben Osman

Publications and source records attributed to A Ben Osman.

At least 19 recordsLinked to original sources
PubMed2006

[Three cases of cutaneous blastomycosis].

Blastomycosis is a rare mycotic infection in Africa. Isolated cutaneous disease is extremely rare. We report three cases of cutaneous blastomycosis confirmed by istologic and mycologic examination. No visceral involvement was found. Blastomycosis is rare in Tunisia. The most common site of involvement is the lung. The three cases reported presented with skin involvement only, suggesting a cutaneous inoculation of Blastomyces dermatitidis. The diagnostic criteria of cutaneous blastomycosis are discussed.

Adolescent↗
PubMed2006

Clinical and mutational investigations of tyrosinemia type II in Northern Tunisia: identification and structural characterization of two novel TAT mutations.

Tyrosinemia type II or Richner-Hanhart Syndrome (RHS) is an autosomal recessive disorder characterized by keratitis, palmoplantar keratosis, mental retardation, and elevated blood tyrosine levels. The disease is due to a deficiency of hepatic cytosolic tyrosine aminotransferase (TATc), an enzyme involved in the tyrosine catabolic pathway. Because of the high rate of consanguinity this disorder seems to be relatively common among the Arab and Mediterranean populations. RHS is characterized by inter and intrafamilial phenotypic variability. A large spectrum of mutations within TATc gene has been shown to be responsible for RHS. In the present study, we report the clinical features and the molecular investigation of RHS in three unrelated consanguineous Tunisian families including 7 patients with confirmed biochemical diagnosis of tyrosinemia type II. Mutation analyses were performed and two novel missense mutations were identified (C151Y) and (L273P) within exon 5 and exon 8, respectively. The 3D-structural characterization of these mutations provides evidence of defective folding of the mutant proteins, and likely alteration of the enzymatic activity. Phenotype variability was observed even among individuals sharing the same pathogenic mutation.

Adult↗
PubMed2004

Anti-desmoglein 1 antibodies in Tunisian healthy subjects: arguments for the role of environmental factors in the occurrence of Tunisian pemphigus foliaceus.

Pemphigus foliaceus is an autoimmune blistering skin disease mediated by autoantibodies directed against desmoglein 1 and occurs as a sporadic form throughout the world, or as an endemic form called fogo selvagem in Brazil. Healthy subjects living in Brazilian endemic areas produce antidesmoglein 1 antibodies, suggesting the role of environmental factors in the initiation of the autoimmune response. Tunisia was described recently as an endemic area where the disease is characterized by its high rate among young people, especially women. An enzyme-linked immunosorbent assay using recombinant desmoglein 1 as antigen was used to detect antibodies against desmoglein 1 and calibrated with sera from 67 French healthy blood donors, 20 French pemphigus foliaceus patients and patients with other bullous skin diseases. When sera from 179 healthy Tunisian blood donors were tested, 31 (17%) were found positive. The desmoglein 1 binding activity of these 31 sera was confirmed in 10 cases by indirect immunofluorescence analysis and/or immunoblotting using human epidermal extract. Subclass analysis of antidesmoglein 1 antibodies showed that they were almost exclusively of the IgG2 subclass in positive normal sera and of IgG4 subclass in patients with PF. Thus, antibodies against desmoglein 1 are prevalent in normal subjects living in Tunisia which, along with their IgG2 isotype, suggests the role of the environment in the pathogenesis of this endemic type of pemphigus foliaceus and the need for additional factors to switch from a subclinical to a clinical form of the disease.

Adolescent↗
PubMed2003

A novel missense mutation in the gene encoding SLURP-1 in patients with Mal de Meleda from northern Tunisia.

BACKGROUND: Mal de Meleda (MDM) is a rare autosomal recessive skin disorder which belongs to the clinically and genetically heterogeneous group of palmoplantar keratodermas (PPK). Clinically, MDM is characterized by erythema and hyperkeratosis of the palms and soles with sharp demarcation that appears soon after birth and progressively extends to the dorsal surface of the hands and feet. OBJECTIVES: Except for the molecular study reported in Algerian families, MDM has not yet been investigated in the Maghrebian population, characterized by its heterogeneous ethnic background and a high rate of consanguinity. In this study we report genetic and molecular investigations of eight unrelated consanguineous Tunisian families including 17 affected individuals. METHODS: Eight large consanguineous MDM families who originated from cities of northern Tunisia, with a total of 17 patients and 22 unaffected family members were investigated. Families were genotyped with the following microsatellite markers: CNG003, D8S1751 and D8S1836. Mutation analyses were performed in affected patients, in both parents and in unaffected individuals. Linkage analysis was also performed. RESULTS: All the clinical features of MDM were constantly present. Nevertheless variable severity was noted among patients. Histological details were recorded. The haplotype analysis of markers CNG003, D8S1751 and D8S1836 revealed that all affected offspring were homozygous by descent for the three polymorphic markers. The maximum lod score value, 3.22, confirmed the evidence for linkage to the ARS gene. Three haplotypes were observed, and the findings suggest that at least three different mutations within the ARS gene segregate with these haplotypes. Three different mutations were identified, the 82delT mutation previously described and two novel missense mutations. CONCLUSIONS: The results suggest that the ARS gene is likely to be responsible for MDM in the eight Tunisian families. The clinical variability in the expression of PPK in MDM Tunisian patients might be accounted for by the intervention of modifier genes influencing the MDM phenotype.

Antigens, Ly↗
PubMed2002

[Surgery for intra-bronchial foreign bodies].

OBJECTIVE: The aim of this study was to evaluate the results of surgical treatment of intra-bronchic foreign bodies after unsuccessful endoscopic extraction. MATERIALS AND METHODS: Fifteen patients underwent surgical treatment of intra-bronchic foreign bodies in our department during a period of 10 years. There was 9 males and 6 females, the mean age was 20.27 years (range between 5 and 39 years), there were 8 right localizations and 7 left. The recurrent pulmonary infections were most frequent complaint of patients. RESULTS: Twelve pulmonary resections (including one pneumonectomy) were necessary because of the importance of pulmonary parenchyma destruction. There was one post-operative complication (one empyema) and the peri-operative mortality was nul. CONCLUSION: Surgical treatment of intra-bronchic foreign bodies must be used only after unsuccessful endoscopic extraction. The preventive measures are the best treatment.

Adolescent↗
PubMed2002

Pemphigus is not associated with allotypic markers of immunoglobulin kappa.

The kappa light chain constant region of immunoglobulins bears polymorphic markers involved in susceptibility to various autoimmune diseases. To determine whether it also contributes to the occurrence of pemphigus, a group of autoimmune blistering skin diseases owing to pathogenic autoantibodies, the genotypic frequencies of Km allotypes were evaluated in patients with pemphigus foliaceus or pemphigus vulgaris and ethnically-matched healthy controls in both Tunisia and France. No difference in the distribution of Km genotype or allele frequencies was observed between patients and controls in either countries. Therefore, Km allotypes do not appear to constitute a genetic factor contributing to pemphigus.

Adult↗
PubMed2000

[Epidemiologic and parasitologic data concerning sporadic cutaneous leishmaniasis in northern Tunisia].

This study refers to 23 patients presenting with the sporadic forms of cutaneous leishmaniasis encountered in northern most humid parts of Tunisia. Culture inoculation for parasitic isolation was processed using two media: the classical NNN and a rabbit serum based medium (SLC). Cultures were positive in 17 cases with SLC medium and 13 cases with NNN medium. Eight isolates were typed using 15 isoenzymes systems. Six isolates were identified as Leishmania infantum MON-24 which confirms the crucial role of this zymodeme in causing this form of cutaneous leishmaniasis. The other two isolates were identified as Leishmania infantum MON-1, which is the principal agent of visceral leishmaniasis in the Mediterranean area.

Adolescent↗
PubMed1999

Leishmanin skin test lymphoproliferative responses and cytokine production after symptomatic or asymptomatic Leishmania major infection in Tunisia.

Resistance to Leishmania parasite infection requires the development of a cellular immune response that activates macrophage leishmanicidal activity. In this study we have investigated the lymphoproliferative responses and in vitro cytokine production of peripheral blood mononuclear cells (PBMC) from individuals living in an endemic area for L. major infection in Tunisia. The results were compared with the DTH reaction of the leishmanin skin test (LST). Sixty-seven individuals were included in the study: 22 persons (age range 9-60 years) who developed, 2 years before the present study, a parasitologically confirmed localized cutaneous leishmaniasis (LCL) that healed spontaneously, and 45 individuals (age range 18-20 years) born and living in the same area, with no previous history of LCL. LST was positive (skin induration > or = 5 mm) in 20/22 cured cases of LCL and in 75% of healthy individuals without history of LCL. LST+ individuals expressed vigorous Leishmania-specific lymphoproliferative responses associated with in vitro production of interferon-gamma (IFN-gamma) but not IL-4. Interestingly, IL-10 was detected in parallel with the highest levels of IFN-gamma in PBMC supernatants from 3/20 cured LCL and 8/25 individuals without history of LCL. Our results showed a 98% concordance between the DTH reaction assessed by LST and the in vitro proliferative assay induced by soluble leishmanial antigens. Moreover, proliferative assays as well as cytokine analysis did not show any significant difference of the immune memory to parasite antigens developed by patients who had overt cutaneous leishmaniasis and those who had apparently asymptomatic infection.

Adolescent↗
PubMed1997

[Vulvar Crohn disease: 3 cases].

BACKGROUND: Vulvar involvement in Crohn's disease is uncommon. The elementary lesion is usually an ulceration: 44 cases have been reported in the literature. In 20 p. 100 of the cases, vulvar involvement is the only manifestation of the disease. We report 3 new cases of vulvar lesions in Crohn's disease. CASE REPORTS: The first case had vulvar lesions which complicated ileocolic Crohn's disease, in the other two cases there were no digestive manifestations. One patient developed voluminous edema of the right labium. The diagnosis of Crohn's disease of the vulva was suggested by the characteristic lesions, presence of epithelioid and giant cell granuloma at histology examination of the vulva specimen and finally on rapidly favorable course after treatment with sulfasalazine. The ulcers regressed with medical treatment but remission was temporary with recurrence at treatment withdrawal. DISCUSSION: These cases underline the difficulties encountered in establishing the diagnosis of Crohn's disease in patients who develop vulvar ulcerations alone with no signs of digestive disease and emphasize the difficult problem of long-term control.

Adolescent↗
PubMed1996

[Tunisian pemphigus. Apropos of 70 cases. (Experience of the dermatology department of La Rabta Hospital 1974-1992)].

INTRODUCTION: Pemphigus frequently seen in Tunisia has specific characteristics distinguishing it from the European or American forms. Between 1974 and 1992, we observed 70 cases in the dermatology unit of the La Rabta University Hospital in Tunis. Most patients were young (mean age 39 yr), predominantly women (80%). Deep pemphigus (pemphigus vulgaris and vegetans) occurred in 56% and superficial pemphigus (seborrheic and foliaceus) in 44%. High-dose corticosteroids were given as initial treatment (1.4 mg/kg/day). Infectious complications were frequent. Mortality was 14%. Pemphigus in Europe and North America usually occurs in adults in the 50-60 year age range. Superficial forms are rare (2-10%). In Tunisia, pemphigus is similar to Brazilian pemphigus with high frequency and predominant superficial forms (pemphigus foliaceus).

Adult↗