Statistics on diffeomorphisms via tangent space representations.

In this paper, we present a linear setting for statistical analysis of shape and an optimization approach based on a recent derivation of a conservation of momentum law for the geodesics of diffeomorphic flow. Once a template is fixed, the space of initial momentum becomes an appropriate space for studying shape via geodesic flow since the flow at any point along the geodesic is completely determined by the momentum at the origin through geodesic shooting equations. The space of initial momentum provides a linear representation of the nonlinear diffeomorphic shape space in which linear statistical analysis can be applied. Specializing to the landmark matching problem of Computational Anatomy, we derive an algorithm for solving the variational problem with respect to the initial momentum and demonstrate principal component analysis (PCA) in this setting with three-dimensional face and hippocampus databases.

Liver toxicity profile in gold-treated Egyptian rheumatoid arthritis patients.

The objective was to evaluate the rationale for liver needle biopsy versus blood liver functional tests in monitoring the incidence of hepatotoxicity in Egyptian rheumatoid arthritic patients treated with gold compounds. Forty patients (12 males, 28 females) were randomly selected out of 258 Egyptian rheumatoid arthritic patients treated with sodium auro-thiomalate during the past 4 years. The minimum duration of treatment was 40 weeks. The methods used were firstly, liver function tests (serum glutamic-oxaloacetic transaminase, serum glutamic-pyruvic transaminase, total serum bilirubin and total serum albumin) before, weekly during and after administration of sodium auro-thiomalate. Secondly, a needle liver biopsy was conducted by using the tru-cut needle. Then liver histology was graded according to Roenigk for grading liver toxicity. Viral hepatitis markers (hepatitis B surface antigen, anti-hepatitis C virus were done for monitoring viral hepatitis. Finally, the liver tissue contents of heavy metals were counted in the cases that showed grade IIIB histological changes. The results showed that none of the studied cases developed any clinically significant liver disease during the course of chrysotherapy. Blood liver function tests were of normal value throughout the course of drug administration. According to Roenigk grading, 20 patients (50%) showed grade I liver changes, and the other 20 patients showed liver changes of grades II and III (four grade II, eight grade IIIA, and another eight grade IIIB). None of the patients showed grade IV liver changes. It was concluded that blood liver tests are not the most sensitive methods to detect hepatotoxicity in gold-receiving Egyptian rheumatoid arthritic patients. Needle liver biopsy is not superior in detecting liver toxicity, compared with routine laboratory liver function tests, because of its complications. Rheumatoid arthritic patients with a potential risk of clinically significant liver disease should not be exposed to the risk of gold salt therapy. Pretreatment HLA-DR genetic typing may be a good detector for rheumatoid arthritic patients with potential risk of hepatotoxicity.