Postural control parameters in elderly female fallers and non-fallers diagnosed or not with knee osteoarthritis

Objectives: To compare stabilometric parameters of elderly female fallers and non-fallers associated or not with knee osteoarthritis (OA). Methods: Fifty-six elderly female fallers and non-fallers diagnosed or not with unilateral or bilateral knee OA were divided into the following groups: FOA (n = 10), elderly female falters with knee OA; FNOA (n = 11), elderly female fallers without knee OA; NFOA (n = 14), elderly female non-fallers with knee OA; and NFNOA (n = 21), elderly female non-fallers without knee OA. For analyzing semi-static balance on a force platform with the elderly females standing, the following parameters were assessed in four conditions: center of pressure (COP), anterior-posterior and mediolateral displacements (APD and MLD, respectively); and COP anterior-posterior and mediolateral displacement velocities (APV and MLV, respectively). The following conditions were assessed: 1) standing on a firm wooden surface with eyes open (WSEO); 2) standing on a firm wooden surface with eyes closed (WSEC); 3) standing on a foam surface with eyes open (FSEO); 4) standing on a foam surface with eyes closed (FSEC). Results: The elderly females with knee OA showed greater APD in all four conditions assessed (P < 0.05), while the elderly female fallers showed greater MLD (P < 0.05). No difference between the groups was observed for APV and MLV (P > 0.05). Conclusions: Knee OA per se increases APD of the COP, while the history of falls, regardless of the presence of knee OA, hinders postural control in the ML direction.

“Features of two proteins of Leptospira interrogans with potential role in host-pathogen interactions”

Abstract Background Leptospirosis is considered a re-emerging infectious disease caused by pathogenic spirochaetes of the genus Leptospira. Pathogenic leptospires have the ability to survive and disseminate to multiple organs after penetrating the host. Leptospires were shown to express surface proteins that interact with the extracellular matrix (ECM) and to plasminogen (PLG). This study examined the interaction of two putative leptospiral proteins with laminin, collagen Type I, collagen Type IV, cellular fibronectin, plasma fibronectin, PLG, factor H and C4bp. Results We show that two leptospiral proteins encoded by LIC11834 and LIC12253 genes interact with laminin in a dose - dependent and saturable mode, with dissociation equilibrium constants (KD) of 367.5 and 415.4 nM, respectively. These proteins were named Lsa33 and Lsa25 (Leptospiral surface adhesin) for LIC11834 and LIC12253, respectively. Metaperiodate - treated laminin reduced Lsa25 - laminin interaction, suggesting that sugar moieties of this ligand participate in this interaction. The Lsa33 is also PLG - binding receptor, with a KD of 23.53 nM, capable of generating plasmin in the presence of an activator. Although in a weak manner, both proteins interact with C4bp, a regulator of complement classical route. In silico analysis together with proteinase K and immunoflorescence data suggest that these proteins might be surface exposed. Moreover, the recombinant proteins partially inhibited leptospiral adherence to immobilized laminin and PLG. Conclusions We believe that these multifunctional proteins have the potential to participate in the interaction of leptospires to hosts by mediating adhesion and by helping the bacteria to escape the immune system and to overcome tissue barriers. To our knowledge, Lsa33 is the first leptospiral protein described to date with the capability of binding laminin, PLG and C4bp in vitro.