In Vitro Characterization of Human Cytomegalovirus-Targeting Therapeutic Monoclonal Antibodies LJP538 and LJP539.

Human cytomegalovirus (HCMV) infection is usually benign in healthy individuals but can cause life-threatening disease in those with compromised immune systems. Approved drugs available to treat HCMV disease, including ganciclovir, cidofovir, and foscarnet, have significant toxicities that limit their use in certain patient populations. LJP538 and LJP539 are human monoclonal antibodies that are being evaluated as immunoglobulin therapeutics. The antibodies target glycoproteins gB and the gH/gL/UL128/UL130/UL131a pentameric complex, respectively. Here we present an in vitro characterization of these antibodies. We show that LJP538 and LJP539 are more potent than a marketed immunoglobulin at inhibiting HCMV infection of various cell lines relevant to pathogenesis. We find that LJP538 and LJP539 are active against a panel of clinical isolates in vitro and demonstrate minor-to-moderate synergy in combination. Passage of HCMV in the presence of LJP538 or LJP539 alone resulted in resistance-associated mutations that mapped to the target genes. However, no loss of susceptibility to the combination of antibodies was observed for >400 days in culture. Finally, the binding regions of LJP538 and LJP539 are conserved among clinical isolates. Taken together, these data support the use of LJP538 and LJP539 in combination for clinical trials in HCMV patients.

Purification and characterization of mutant miniPlasmin for thrombolytic therapy.

BACKGROUND: Previous animal studies by us and others have indicated that catheter-administered plasmin or its des-kringle derivatives may be more appropriate alternatives to plasminogen activators for treating thrombolytic diseases, since it has a very short serum half-life and therefore does not result in hemorrhaging. We have previously produced recombinant miniPlasmin (mPlasmin) that was proven suitable for treating peripheral arterial occlusion in animal models. However, our previous results showed that non-specific cleavage at position K698 of mPlasmin during activation hindered the further development of this promising therapeutic candidate. In order to minimize or eliminate the non-specific cleavage problem, we performed saturation mutagenesis at the K698 position to develop a mutant form of mPlasmin for thrombolytic therapy. METHODS: We changed K698 to 16 other amino acids, with preferred E. coli codons. Each of these mutants were expressed in E. coli as inclusion bodies and then refolded, purified, and subsequently characterized by detailed kinetic assays/experiments/studies which identified highly active mutants devoid of non-specific cleavage. RESULTS: Activation studies indicated that at those conditions in which the wild type enzyme is cut at the non-specific position K698, the active mutants can be activated without being cleaved at this position. CONCLUSIONS: From the above results, we selected two mutants, K698Q and K698N, as our lead candidates for further thrombolytic drug developments. The selected mutants are potentially better therapeutic candidates for thrombolytic therapy.

Multivariate analysis of the factors affecting duration of acute inpatient rehabilitation after hip and knee arthroplasty.

OBJECTIVE: To determine which factors predict length of stay at a rehabilitation hospital for total hip and knee arthroplasty patients. DESIGN: Length of stay at an acute rehabilitation hospital was analyzed with respect to demographic, surgical, and comorbidity factors using univariate and multivariate statistical techniques. Data were retrospectively collected of 808 hip and knee arthroplasty rehabilitation patients from years 2000 and 2001 at a large, urban, university-affiliated acute rehabilitation hospital. Demographic factors included age, insurance, marital status, sex, race, and body mass index. Surgical factors included knee/hip arthroplasty, unilateral/bilateral arthroplasty, and indication for surgery. Also, the 22 most prevalent comorbid illnesses for the patient group were analyzed for their association with length of stay. RESULTS: Significant factors for predicting length of stay were indication for surgery, number of comorbid illnesses, unmarried marital status, and black race. Also, advanced age and male sex approached significance. CONCLUSION: Length of stay in rehabilitation for total hip arthroplasty and total knee arthroplasty can be statistically modeled using various factors. These findings will help clinicians address prolonged length of stay and resource allocation issues.

Effects of characteristics of image quality in an immersive environment.

Image quality issues such as field of view (FOV) and resolution are important for evaluating "presence" and simulator sickness (SS) in virtual environments (VEs). This research examined effects on postural stability of varying FOV, image resolution, and scene content in an immersive visual display. Two different scenes (a photograph of a fountain and a simple radial pattern) at two different resolutions were tested using six FOVs (30, 60, 90, 120, 150, and 180 deg.). Both postural stability, recorded by force plates, and subjective difficulty ratings varied as a function of FOV, scene content, and image resolution. Subjects exhibited more balance disturbance and reported more difficulty in maintaining posture in the wide-FOV, high-resolution, and natural scene conditions.