A mathematical model of the response of semicircular canal and otolith to head rotation under gravity.

The mathematical model of the system composed of two sensors: semicircular canal and sacculus, is presented. The system is described by three series of blocks: biomechanical block, mechanoelectrical transduction mechanism and hair cell ionic currents and membrane potential dynamics. The response of the aforecited system to various stimuli (head rotation under gravity and falling) was investigated. The identification of the model parameters was fulfilled for the experimental data, obtained for the axolotle (Ambystoma tigrinum) in Institute of Physiology, Autonomous University of Puebla, Mexico. The comparative analysis of canal and sacculus membrane potential was realized.

Serodiagnosis of tuberculosis: detection of mycobacterial antibodies and antigens.

SETTING: The diagnosis of tuberculosis is based primarily on identification of mycobacteria and on clinical evidence. Recently, serological studies have been widely used experimentally as a diagnostic approach. OBJECTIVE: The aim of our study was to optimize serodiagnosis of tuberculosis by detecting mycobacterial antigens and antibodies in sera from patients with lung tuberculosis, non-related diseases and healthy controls. DESIGN: Mycobacterium tuberculosis H37Rv was disintegrated by pressure. Cell walls were extracted with 3 M KCL and were subjected to gel filtration in Toyopearl gel. Immune sera were prepared by immunization of rabbits with cell wall material. Anti H37Rv antibodies were purified by affinity chromatography. The reagents obtained were used to detect serum antibodies and antigens (following immune complex dissociation) using ELISA. RESULTS: Using fraction 6 of cell wall extract, antibodies were detected in 72.2% of TB patients; there were no positive reactions in control subjects. By use of affinity-purified antibodies, antigens were detected in 77.1% of TB patients, 10% of patients with unrelated diseases and 6.7% of healthy controls. CONCLUSION: Effective serodiagnosis of tuberculosis can be achieved only by combining detection of both circulating antibodies and antigens using highly specific purified reagents and immune complex-dissociated sera.