Immunohistological study of tight junction protein expression in mal de Meleda.

Mal de Meleda (MdM, MIM: 248300) is a rare autosomal recessive skin disorder characterized by diffuse palmoplantar keratoderma and transgressive keratosis with onset in early infancy. The gene responsible for MdM, ARS, encodes for Secreted Lys6/Plaur domain-containing protein 1 which is essential for epidermal homeostasis. Tight junctions have been proposed to have two mutually exclusive functions: a fence function which prevents the mixing of membrane proteins between the apical and basolateral membranes; and a gate function which controls the paracellular passage of ions and solutes between cells. In this study we report immunohistochemical investigations of tight junction proteins claudin-1 and occludin in MdM Tunisian families. Nine skin biopsies from patients with MdM were analyzed. The control group was formed by skin biopsies belonging to healthy individuals. Immunohistochemical study was performed on fixed sections from biopsies of four microns with the following polyclonal antibodies: anti-claudin-1 and anti-occludin. In control skin, claudin-1 exhibited membrane expression throughout the epidermis with increasing and upward intensity, whereas occludin was detected in the cell membrane of keratinocytes of the stratum granulosum. In MdM skin, claudin-1 was expressed throughout the thickness of the spinous layers with membrane staining, and occludin had cytoplasmic staining in the granular layer. The immunohistochemical expression of TJ proteins in MdM patients harbors premature expression of occludin and decreased expression of claudin-1, highlighting further evidence for disorders in epidermal homeostasis.

Prognostic impact of angiogenesis in nonmuscle invasive bladder cancer as defined by microvessel density after immunohistochemical staining for CD34.

Bladder cancer is the second most common malignancy of the urogenital region. The majority of bladder cancer deaths occur as a consequence of metastatic disease. Microvessel density (MVD), a surrogate marker for angiogenesis, has been shown to be predictive of progression and poor prognosis. The aim of this study was to evaluate the predictive value and prognostic significance of angiogenesis in human non muscle invasive bladder cancer (NMIBC) treated by BCG immunotherapy. The frozen sections of 28 non muscle invasive bladder cancer specimens were stained with CD34 antibody to label the vascular endothelium using the standard streptavidin-biotin immunoperoxidase method. Angiogenic activity was measured using microvessel count determined by the expression of vascular markers CD34.The prognostic significance of tumor stage, grade, loci number, tumor size, age and CD34 expression in determining the risk for recurrence was studied with both univariate and multivariate methods of analysis. According to univariate analysis of the prognostic significance for tumor stage, grade, tumor size, loci number, age and CD34 expression, in patients with NMIBC, the pT1 stage and high grade seem to be associated in a statistically significant manner with higher risk for recurrence (P=0.004, P=0.004, respectively). In the other hand, multivariate Cox regression's analysis showed that microvessel density and multiplicity were independent predictor of recurrence after BCG immunotherapy (p=0.016, p=0.032, respectively). This study provides strong evidence that CD34 MVD is associated with recurrence after BCG immunotherapy. Independent studies, however, will be required on larger cohort to validate these findings.

Novel and recurrent mutations in the TAT gene in Tunisian families affected with Richner-Hanhart syndrome.

Tyrosinemia type II, also designated as oculocutaneous tyrosinemia or Richner-Hanhart syndrome (RHS), is a very rare autosomal recessive disorder. In the present study, we report clinical features and molecular genetic investigation of the tyrosine aminotransferase (TAT) gene in two young patients, both born to consanguineous unions between first-degree cousins. These two unrelated families originated from Northern and Southern Tunisia. The clinical diagnosis was based on the observation of several complications related to Richner-Hanhart syndrome: recurrent eye redness, tearing and burning pain, photophobia, bilateral pseudodendritic keratitis, an erythematous and painful focal palmo-plantar hyperkeratosis and a mild delay of mental development. The diagnosis was confirmed by biochemical analysis. Sequencing of the TAT gene revealed the presence of a previously reported missense mutation (c.452G>A, p.Cys151Tyr) in a Tunisian family, and a novel G duplication (c.869dupG, p.Trp291Leufs 6). Early diagnosis of RHS and protein-restricted diet are crucial to reduce the risk and the severity of long-term complications of hypertyrosinemia such as intellectual disability.