The use of venous blood gas in assessing arterial acid-base and oxygenation status - an analysis of aggregated data from multiple studies evaluating the venous to arterial conversion (v-TAC) method.

BACKGROUND: Several methods exist toreduce the number of arterial blood gases (ABGs). One method, Roche v-TAC, hasbeen evaluated in different patient groups. This paper aggregates data from thesestudies, in different patient categories using common analysis criteria. RESEARCH DESIGN AND METHODS: We included studiesevaluating v-TAC based on paired arterial and peripheral venous blood samples.Bland-Altman analysis compared measured and calculated arterial values of pH, PCO2and PO2. Subgroup analyses were performed for normal, chronichypercapnia and chronic base excess, acute hyper- and hypocapnia, and acute andchronic base deficit. RESULTS: 811 samples from 12 studieswere included. Bias and limits of agreement for measured and calculated values:pH 0.001 (-0.029 to 0.031), PCO2 -0.08 (-0.65 to 0.49) kPa, and PO20.04 (-1.71 to 1.78) kPa, with similar values for all sub-group analyses. CONCLUSION: These data suggest thatv-TAC analysis may have a role in replacing ABGs, avoiding arterial puncture.Substantial data exists in patients with chronic hypercapnia and chronic baseexcess, acute hyper and hypocapnia, and in patients with relatively normal acidbase status, with similar bias and precision across groups and across studydata. Limited data exists for patients with acute and chronic base deficit.

Development of a novel recombinant biotherapeutic with applications in targeted therapy of human arthritis.

OBJECTIVE: To isolate recombinant antibodies with specificity for human arthritic synovium and to develop targeting reagents with joint-specific delivery capacity for therapeutic and/or diagnostic applications. METHODS: In vivo single-chain Fv (scFv) antibody phage display screening using a human synovial xenograft model was used to isolate antibodies specific to the microvasculature of human arthritic synovium. Single-chain Fv antibody tissue-specific reactivity was assessed by immunostaining of synovial tissues from normal controls and from patients with rheumatoid arthritis and osteoarthritis, normal human tissue arrays, and tissues from other patients with inflammatory diseases displaying neovasculogenesis. In vivo scFv antibody tissue-specific targeting capacity was examined in the human synovial xenograft model using both (125)I-labeled and biotinylated antibody. RESULTS: We isolated a novel recombinant human antibody, scFv A7, with specificity for the microvasculature of human arthritic synovium. We showed that in vivo, this antibody could efficiently target human synovial microvasculature in SCID mice transplanted with human arthritic synovial xenografts. Our results demonstrated that scFv A7 antibody had no reactivity with the microvasculature or with other cellular components found in a comprehensive range of normal human tissues including normal human synovium. Further, we showed that the reactivity of the scFv A7 antibody was not a common feature of neovasculogenesis associated with chronic inflammatory conditions. CONCLUSION: Here we report for the first time the identification of an scFv antibody, A7, that specifically recognizes an epitope expressed in the microvasculature of human arthritic synovium and that has the potential to be developed as a joint-specific pharmaceutical.