Hydatidosis: Preparation and evaluation of radiolabeled antigens and antibodies.

The present preliminary study intends to evaluate the in vitro use of hydatid antigen and their antibodies once labeled with iodine 125(I125) and characterized from viewpoint of radiochemical purity and immunoreactivity. Radiolabelled molecules gave satisfactory purity of 94% and 96%-98%, for hydatid antigen and IgG respectively. As regards, the specific activity of these latter, varied between 4.79 and 5.97 µCi/µg. The specificity test of radiolabelled IgG against the hydatid membranes showed a significant recognition that increased proportionally according to the contact surface. Likewise this immunoreactivity test performed with a simple binding assay, using human hydatid fluid antigen (HHF-Ag), previously fixed on a solid phase, gave satisfactory fixation rate of the order of 356 ±â€¯48.08cpm, 2539 ±â€¯550.12cpm and 6558 ±â€¯712.76cpm for the concentrations of 0.1 µg/ml, 2 µg/ml and 25 µg/ml respectively. Statistical study of 88 sera, carried out with radiolabelled antigen (125I-HHF-Ag) in competitive radioimmunoassay test (CRIA) showed highly significant difference (p < 0.0001) in the binding capacity of antigens from patients sera with hydatid disease (65.63 ±â€¯9.12) compared to the negative sera (19.25 ±â€¯14.84). No cross reaction was observed using sera from patients with toxoplasmosis (33, 07 ±â€¯13, 07) and the difference was highly significant (p < 0.0001) compared to E granulosus infected patient sera. Furthermore, this test seemed to be sensitive since among the 43 sera tested, only 37 (86%) were found to be positive by passive hemagglutination (HAP), while the totality (100%) responded positively by CRIA. Our findings are encouraging, suggesting that these radiolabeled molecules could be useful for advancing toward new diagnostic and therapeutic modalities.

[Magnetic resonance imaging and the discoid meniscus in children]. / Imagerie par résonance magnétique et ménisque discoïde chez l'enfant.

Discoid meniscus is an uncommon dysplasia generally affecting the lateral meniscus. Its congenital or acquired origin remains a question of debate. We report 5 cases or lateral discoid meniscus in 4 girls and 1 boy, aged from 6 to 11 years. The main clinical signs were snapping knee and pain. The discoid meniscus appeared in MRI as an abnormally large meniscus extending into the joint space. It appeared as a central band giving increased signal in 3 out of 5 cases. The significance of this probably trauma-induced image was uncertain. Surgery confirmed MRI findings in 4 cases in which total resection of the meniscus was performed. No operation was performed in the fifth case.