A standard set of outcome measures for the comprehensive assessment of osteogenesis imperfecta.

BACKGROUND: Osteogenesis Imperfecta (OI) is a genetic disorder also known as 'brittle bone disease'. The clinical manifestation of OI shows a wide variation. Therefore, care for patients with OI requires an interdisciplinary approach. The effectiveness of particular interventions and treatment protocols of interdisciplinary teams is not clear due to a non-standardized and wide variation of patient outcomes thus making the comparison of outcome measures available in the literature difficult. It is only by agreeing on a common, standard set of outcome measures for the comprehensive appraisal of OI that comparisons across interdisciplinary treatment centers for OI will be possible in the future. METHODS: The Key4OI international interdisciplinary working group of 27 members used a consensus-driven modified Delphi approach to develop a set of global outcome measures for patients with OI. The International Classification of Functioning, Disability and Health (ICF), was used to define domains and organize the outcomes from the literature search. After reviewing the outcomes extracted from the literature, trials and registries, the working group agreed on a final selection of domains and their definition (ICF definition as well as a lay description). These domains were then presented to the focus groups who prioritized the outcome domains by taking into account the items important to the OI community. All content was collected and analyzed and final domains were determined. A consensus of appropriate measuring instruments for each domain was reached with Delphi rounds. The entire approach was in line with the International Consortium for Health Outcomes Measurement ICHOM methodology. RESULTS: More than 400 different outcome measures were identified in our literature search. After three Delphi rounds, 24 domains were selected. After the focus group sessions, the number of domains were reduced to 15. A consensus was reached on the measuring instruments to cover these domains for both children and adults. CONCLUSION: The Key4OI project resulted in standard set of outcome measures focused on the needs and wishes of individuals with OI and their families. This outcome set will enable healthcare teams and systems to compare and to improve their care pathways and quality of care worldwide. Further studies are needed to evaluate the implementation of this standardized outcome set.

Sustained and specific in vitro inhibition of HIV-1 replication by a protease inhibitor encapsulated in gp120-targeted liposomes.

Selective delivery of antiretrovirals to human immunodeficiency virus (HIV) infected cells may reduce toxicities associated with long-term highly active antiretroviral therapy (HAART), may improve therapeutic compliance and delay the emergence of resistance. We developed sterically stabilized pegylated liposomes coated with targeting ligands derived from the Fab' fragment of HIV-gp120-directed monoclonal antibody F105, and evaluated these liposomes as vehicles for targeted delivery of a novel HIV-1 protease inhibitor. We demonstrated that the immunoliposomes were selectively taken up by HIV-1-infected cells and localized intracellularly, enabling the establishment of a cytoplasmic reservoir of protease inhibitor. In antiviral experiments, the drug delivered by the immunoliposomes showed greater and longer antiviral activity than comparable concentrations of free drug or drug encapsulated in non-targeted liposomes. In conclusion, by combining a targeting moiety with drug-loaded liposomes, efficient and specific uptake by non-phagocytic HIV-infected cells was facilitated, resulting in drug delivery to infected cells. This approach to targeted delivery of antiretroviral compounds may enable the design of drug regimens for patients that allow increased therapeutic adherence and less toxic treatment of HIV infection.

Production of human immunodeficiency virus type 1 (HIV-1) pseudoviruses using linear HIV-1 envelope expression cassettes.

HIV-1 pseudoviruses constitute an important tool in HIV-1 vaccine and entry inhibitor research. Single-cycle pseudoviruses carrying functional envelopes are generated by co-transfecting HEK293T cells with pNL4-3.LucR(-)E(-) and Env expression plasmids. However, cloning of Env genes is time consuming and single Env clones are not representative of the diversity of HIV-1 in a patient's blood sample. A new method to construct Env expression cassettes is proposed which can be used for the rapid generation of heterogeneous HIV-1 pseudoviruses without a cloning step. The linear Env expression cassettes are constructed by ligating PCR amplified Env genes between a 5' CMV promoter and 3' SV40 polyadenylation element. The resulting cassettes generate pseudoviruses carrying heterogeneous Env variants of a primary HIV-1 isolate derived from viral RNA or proviral DNA. The influence of cis-acting sequences upstream of the Env gene on infectivity was compared between pseudoviruses generated from plasmids and linear expression cassettes. The results suggest that the presence of these upstream sequences tends to result in higher infectivity of pseudoviruses when present in heterogeneous Env expression cassettes, but they do not enhance infectivity of pseudoviruses generated with homogeneous Env expression constructs. Using linear expression cassettes allows for the rapid production of heterogeneous patient-derived functional Env genes.

Binding kinetics, uptake and intracellular accumulation of F105, an anti-gp120 human IgG1kappa monoclonal antibody, in HIV-1 infected cells.

The use of targeting moieties is a new and exciting field of scientific research for facilitating the specific delivery of therapeutic agents in HIV-infected patients. The interaction of a potential targeting moiety with its ligand is a crucial factor in the evaluation of a targeted approach for chemotherapeutic intervention. Therefore, we have further characterized the interaction between a potential targeting agent, the monoclonal human antibody F105, and its ligand gp120, a glycoprotein expressed on the surface of HIV-1 infected cells. We demonstrate the specificity of binding and entry of F105 to infected cells. F105 was rapidly taken up into the cell and accumulated in the Golgi apparatus. Kinetic analysis of the F105-gp120 interaction revealed an equilibrium dissociation constant (K(D)) of 0.62 nM, compared with the gp120-CD4 interaction where the K(D) was determined at 35 nM. Consequently, F105 displayed a higher gp120 affinity. This was due to a slower dissociation as compared with the natural ligand. These data further underline the potential of monoclonal antibodies as targeting agents, and offer new insights into the possibility of F105 as a targeting moiety for the delivery of antiretroviral drugs to HIV-1 infected cells.

Comparative analysis of 10 small molecules binding to carbonic anhydrase II by different investigators using Biacore technology.

In this benchmark study, 26 investigators were asked to characterize the kinetics and affinities of 10 sulfonamide inhibitors binding to the enzyme carbonic anhydrase II using Biacore optical biosensors. A majority of the participants collected data that could be fit to a 1:1 interaction model, but a subset of the data sets obtained from some instruments were of poor quality. The experimental errors in the k(a), k(d), and K(D) parameters determined for each of the compounds averaged 34, 24, and 37%, respectively. As expected, the greatest variation in the reported constants was observed for compounds with exceptionally weak affinity and/or fast association rates. The binding constants determined using the biosensor correlated well with solution-based titration calorimetry measurements. The results of this study provide insight into the challenges, as well as the level of experimental variation, that one would expect to observe when using Biacore technology for small molecule analyses.