No abstract

Activation of complement results in formation of membrane attack complexes (MACs) that can insert themselves either into cells that initiate complement activation or into nearby ("innocent bystander") cells. The MACs form large-conductance, nonspecific ion channels that can cause lytic or sublytic cell damage. The authors used a highly sensitive patch clamp technique to assess the contribution of the bystander effect to the pathophysiology of cerebral vasospasm. They compared the effect of complement activation by autologous aged versus fresh erythrocytes on the membrane conductance of freshly isolated rat cerebral artery smooth-muscle cells. In the presence of autologous serum aged, but not fresh, erythrocytes caused a large increase in membrane conductance, an effect that was prevented by heat-inactivating the serum. Ethyleneglycol tetraacetic acid in the presence of Mg++ attenuated the effect, indicating that complement activation was taking place via the classic pathway. The effect was reproduced by zymosan-activated autologous serum, suggesting that such changes in conductance could result from insertion of MACs secondary to a bystander effect. Both C8- and C9-depleted heterologous sera produced minimal effects that were converted to full effect by addition of the missing complement component. Superoxide dismutase plus catalase did not attenuate the conductance changes produced by autologous serum plus aged erythrocytes. Autologous serum plus aged erythrocyte membrane ghosts that were free of lysate caused a typical increase in conductance. This study demonstrates that complement activation by aged erythrocytes can result in MAC insertion into innocent bystander smooth-muscle cell membranes and that this mechanism, heretofore undescribed, may contribute to development of vasospasm after subarachnoid hemorrhage.

Introduction The Bone and Joint Monitor Project was developed to quantify the global burden of musculoskeletal conditions and develop strategies for their prevention. Experts within the Monitor Project have worked previously with officers at the World Health Organization (WHO) to estimate morbidity and mortality associated with rheumatic conditions. The present collaboration seeks means of providing additional and more current burden data. Objective To develop recommendations for performing epidemiological studies in sample populations with musculoskeletal conditions and problems, accounting for determinants and consequences to the individual and society. Methods Recommendations have been developed identifying the most relevant domains for measuring and monitoring the various musculoskeletal conditions by review of epidemiological data on occurrence, determinants and outcomes, and by expert opinion. Instruments that measure these domains were reviewed. Results The domains recommended follow the principles of the WHO International Classification of Functioning, Disability and Health [1,2], and consider: health condition; body function and structure; activity limitation; participation restriction; personal and environmental contextual factors; and, in addition, the resource utilisation and social consequences. The musculoskeletal conditions and problems considered were osteoarthitis, inflammatory arthritis, osteoporosis, spinal problems, musculoskeletal trauma and injuries, and musculoskeletal pain with restricted activity. The selection of indicators for each domain considered the feasibility of their use in a health interview survey (HIS), a health examination survey (HES), a register or a clinical study. Consensus on case definition was reached depending on the study methodology. For example, osteoporosis defined by bone densitometry cannot be ascertained in an HIS, whereas the outcome of osteoporosis (i.e. fragility fracture) can be. Osteoarthitis can be identified as joint pain in an HIS but the preferred definition is pain with X-ray changes and can only be ascertained in an HES. Previously validated generic and disease-specific instruments have been identified that include indicators for all or most of the recommended domains for the consequences of the different conditions and problems. The indicators of the domains for resource utilisation and social consequences and feasibility for collection will vary in different socioeconomic and geographic areas. Guidance on sampling methods is also being developed. Conclusions The comparability of data collected across the globe will improve by the application of agreed upon indicators that consider key domains for the different musculoskeletal conditions and problems in epidemiological studies conducted in different populations.

Heterogeneity and multifactoriality complicate diagnostics and our understanding of pathogenesis of rheumatoid arthritis (RA). The only accepted serologic parameter (rheumatoid factor [RF]) is not disease specific, nor are any of several novel RA autoantibodies. We aimed at identifying profiles instead of individual autoreactivities allowing for unambiguous prediction of RA. Selected RA autoantigens were tested by ELISA (RF and anti-cyclic citrullinated peptide [anti-CCP]) or Western blot (heavy-chain-binding protein [BiP], heterogeneous ribonucleoprotein particle A2 [RA33/ hnRNP A2], calpastatin and calreticulin). Antibody reactivities were assayed from serum samples of 149 RA patients and 132 patients with other rheumatic diseases and from synovial fluids (SF) (58 RA, 65 non-RA). No single autoreactivity was sufficient for unambiguous prediction of RA. Frequencies of multiparameter profiles consisting of 3, 4, 5 and 6 autoreactivites were determined. Fifteen six-parameter serum profiles were exclusively expressed in RA patients, representing a cumulative sensitivity of 59%. Twelve SF profiles were exclusively expressed in 64% of RA patients. The self-learning classification algorithm CLASSIF1 was capable of accurately predicting RA when these profiles were present. Data profile analysis of RF/CCP/BiP/calpastatin/calreticulin/RA33 provided specific discrimination of 64% of RA. Most importantly, RA specific profiles were observed in 64% of patients with early disease (<12 months). For the first time, the accurate prediction of the class RA has been achieved by the use of multiparametric autoreactivity profiles. Because of early expression in disease, these profiles make it possible to start a disease-modifying therapy long before irreversible bone and joint destruction may develop. Additional RA-specific profiles are required to cover the entire group of RA patients. 2 Investigation of the reactivity patterns of antifilaggrin antibodies in sera and synovial fluids from patients with rheumatoid arthritis using citrullinated synthetic peptides

#4126 Background: β1 integrin signaling has been implicated in breast cancer progression and has been shown to facilitate resistance to radiation that could be abrogated using β1 integrin inhibitory antibody, AIIB2. In the present study, we investigated whether a specific alpha heterodimer of β1 integrin was preferentially mediating a pro-survival signal in human breast cancer cells, and if it could specifically be targeted for therapy.&#x2028; Materials and Methods: We used three-dimensional (3D) laminin-rich extracellular matrix (lrECM) culture to compare the relative levels of alpha heterodimer expression in malignant HMT3522-T4-2 and nonmalignant cell line HMT3522-S-1. Total cell lysates were probed by western blot to detect several possible alpha integrins. In addition, to investigate whether α5β1 mediated an important pro-survival signal, we treated 3D lrECM cultures with a small peptide inhibitor of α5β1 integrin and fibronectin interaction, Ac-PHSCN-NH2 (ATN-161) and measured apoptotic response using TUNEL (terminal deoxynucleotidyl transferase (TdT)-mediated nick end labeling) assay.&#x2028; Results: We found that expression of α5β1 was upregulated in HMT3522-T4-2 malignant breast cell line compared to nonmalignant cell line HMT3522-S-1. Inhibition using ATN-161 resulted in a significant dose-dependent increase in TUNEL positive cells.&#x2028; Discussion: We have previously shown that inhibitory antibody to β1 integrin, AIIB2, leads to selective apoptosis and decreased proliferation in human breast cancer cells in 3DlrECM culture and in vivo. In addition, combining β1 integrin inhibition with IR allowed for reduction of IR dose necessary to achieve growth inhibition in vivo. Here, we show that in HMT3522-T4-2 breast cancer cell line, inhibition of α5 integrin and fibronectin interaction using ATN-161 significantly enhanced apoptosis in 3D lrECM. These data indicate that fibronectin and its receptor, α5β1 are important for survival signaling in breast cancer and may be an important target to enhance radiotherapy efficacy. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4126.