Constrained Statistical Modelling of Knee Flexion from Multi-Pose Magnetic Resonance Imaging

© 1982-2012 IEEE.Reconstruction of the anterior cruciate ligament (ACL) through arthroscopy is one of the most common procedures in orthopaedics. It requires accurate alignment and drilling of the tibial and femoral tunnels through which the ligament graft is attached. Although commercial computer-Assisted navigation systems exist to guide the placement of these tunnels, most of them are limited to a fixed pose without due consideration of dynamic factors involved in different knee flexion angles. This paper presents a new model for intraoperative guidance of arthroscopic ACL reconstruction with reduced error particularly in the ligament attachment area. The method uses 3D preoperative data at different flexion angles to build a subject-specific statistical model of knee pose. To circumvent the problem of limited training samples and ensure physically meaningful pose instantiation, homogeneous transformations between different poses and local-deformation finite element modelling are used to enlarge the training set. Subsequently, an anatomical geodesic flexion analysis is performed to extract the subject-specific flexion characteristics. The advantages of the method were also tested by detailed comparison to standard Principal Component Analysis (PCA), nonlinear PCA without training set enlargement, and other state-of-The-Art articulated joint modelling methods. The method yielded sub-millimetre accuracy, demonstrating its potential clinical value

Polyphenolic content and pharmacological potential of french BFA propolis extracts

Propolis, or bee glue, is a natural resinous hive product collected by honeybees from buds and exudates of various trees and plants. Mixed with beewax and salivary enzymes, it is employed to fill cracks and embalm dead invaders in the hive. Propolis has been used in folk medecine since ancien times due to its pharmacological potential associated with antioxidant, antifungal, antibacterial as well as antitumoral properties. A batch of various French propolis extracts, supplied by “Ballot-Flurin Apiculteurs” (BFA), a company located in the South-West of France and specialized in apitherapy products, was fractionated and analysed by HPLC/MS. Its qualitative chemical composition highlights the presence of polyphenols such as hydroxycinnamic acid derivatives and flavonoids. Total polyphenol content and antioxidant activities were evaluated on six BFA propolis extracts, using respectively Folin-Ciocalteu, DPPH and ORAC assays. Preliminary antifungal (Candida albicans) and antibacterial (Staphylococcus aureus) evaluations will also be given

Purification hemisynthesis of xanthatin derivates and in vitro evaluation of their activity towards farnesyltransferase (PFTase)

Originating from America and introduced a few centuries ago in Europe, Xanthium macrocarpum DC. (Asteraceae) also called „Lampourde à gros fruits“ is a species commonly growing on the edges of the Loire. Xanthanolides (sesquiterpene lactones) found in this plant exhibit interesting biological activities [1]. These activities are usually explained by their alkylating properties due to the presence of the α-methylene-γ-lactone function which is also related to the toxicity of several plants. As recent reports pointed out the potential of dimeric or monomeric sesquiterpene lactones as farnesyltransferase (PFTase) inhibitors, we decided to explore this activity knowing that PFTase is an interesting target to find new effective therapeutic agents for the treatment of cancer. So, the objective was to obtained atoxic hemisynthetic derivates from the natural xanthanolides: xanthatin and xanthinin. These compounds were first isolated in one step from the crude chloroformic extract of the leaves of X. macrocarpum using differents methods of chromatography: silica gel and a 5L pilot scale FCPC® (Fast Centrifungal Partition Chromatograph, Kromaton, Angers, France). We have shown that FCPC® is more efficient for purification: solvent consumption is lowered (divided by 2), with highest purity (5 fold increase on average), high loading capacity (2g of extract/L of organic solvent), and manipulation time reduction (few hours versus few days) [2]. Sixteen derivates were investigated as potent inhibitors of protein farnesyl transferase. These results showed that the α-methylene-γ-lactone function is not required to insure a PFTase inhibitory activity whereas the α-methyl-γ-lactone function is responsible for a non competitive-inhibition

Antileishmanial polyphenols from Garcinia vieillardii

Seven xanthones, the new vieillardiixanthones B and C (1) and (7), pancixanthones A (2), B (3), 1,6-dihydroxyxanthone (6), pyranojacareubin and 5,6-O-dimethyl-2-deprenylrheediaxanthone together with two benzophenones, clusiachromene (4) and 3-geranyl-2,4,6-trihydroxybenzophenone (5) were isolated from the stem bark of the neocaledonian Garcinia vieillardii. 2, 5 and 6 showed a significant antileishmanial activity against the promastigote forms of Leishmania mexicana and L. infantum and against the amastigote forms of L. infantum

Anti-AGEs and antiparasitic activity of an original prenylated isoflavonoid and flavanones isolated from Derris ferruginea

A new isoflavonoid, 5-hydroxy-3-(4-hydroxyphenyl)-8-isopropenyl-8,9-dihydro-4H-furo-[2,3-h]-chromen-4-one named derrisisoflavone G (1), four known prenylated flavanones (2–5), four known isoflavonoids (6–9) and two phenolic derivatives (10, 11) have been isolated from crude extracts of Derris ferruginea stems and leaves. Compounds 1–11 were identified using spectroscopic methods whereas an unambiguous structural assignment of 1 was accomplished through hemi-synthesis. Compounds 2–5 exhibited strong in vitro antiparasitic activity against Plasmodium falciparum and Leishmania major but with poor selectivity, whereas 1–5 significantly inhibited the formation of advanced glycation endproducts (AGEs)