Biomedical subjects

Ray Field

Publications and source records attributed to Ray Field.

3 recordsLinked to original sources

PubMed2002

Antibody-induced lysis of isolated rat epididymal adipocytes and complement activation in vivo.

OBJECTIVE: To identify human monoclonal antibodies selectively binding to human adipocytes and to evaluate their ability to induce lysis of isolated rat adipocytes in vitro and to reduce rat complement levels in vivo. RESEARCH METHODS AND PROCEDURES: Using phage display technology, human monoclonal antibodies binding to human adipocyte plasma membranes were identified. Three antibodies (Fat 13, Fat 37, and Fat 41) were selected based on their additional cross-reaction with rat adipocytes and reformatted as a rat chimeric IgG2bs. The ability of these antibodies, both singly and in combination, to induce lysis of rat epididymal adipocytes in vitro and the reduction of serum complement levels in vivo in the rat was evaluated. RESULTS: All antibodies caused similar time- and dose-dependent lysis of isolated rat adipocytes. Calculated mean EC(50) values (maximum percentage of lysis in parentheses) were 0.680 microg/mL (63.2%), 0.546 microg/mL (72.4%), and 0.391 microg/mL (73.7%) for Fat 13, Fat 37, and Fat 41, respectively. Combinations were no more effective than individual antibodies in inducing lysis. Anti-adipocyte antibodies (both singly and in combination) were also similarly effective in vivo. In rats, doses of monoclonal antibody up to 10 mg/kg intraperitoneal generally caused almost complete depletion of serum complement up to 24 hours after dosing recovering to baseline values by day 5. DISCUSSION: Individual and combinations of monoclonal anti-adipocyte antibodies produced a complement-dependent and concentration-dependent activity to lyse adipocytes in vitro and in vivo as measured by a dramatic depletion in serum complement.

Adipocytes↗

PubMedDate not supplied

Improved fermentation processes for NS0 cell lines expressing human antibodies and glutamine synthetase.

To meet the increasing requirement for therapeutic antibodies to conduct clinical trials, an enhanced culture medium and fed-batch process was developed for GS-NS0 cell lines. This process was shown to produce high concentrations of monoclonal antibodies for several cell lines expressing different antibodies. Cells were adapted to growth in a glutamine- and serum-free medium containing bovine serum albumin (BSA), cholesterol, and transferrin. A number of amino acids were found to be depleted during cell culture. The concentrations of these amino acids were increased, and further cell culture analyses were performed. This process of cell growth and analysis was repeated over multiple cycles until no depletion was detected. This resulted in an amino acid supplement that was shown to be generic and enhanced antibody productivity up to 5-fold for the three cell lines tested. Transferrin was replaced using tropolone, a lipophilic iron chelator and ferric ammonium citrate. Cell growth was equivalent to that in transferrin-containing medium over the wide ranges tested. A concentrated feed solution, based on the amino acid supplement and the components of the serum- and protein-free supplements, was formulated. Addition of this feed in response to metabolic requirements resulted in a harvest titer a further 2-fold higher than the enhanced culture medium. Harvest antibody titers of up to 600 mg/L were achieved for three cell lines expressing different antibodies, representing an increase of 10-fold over the starting concentrations.

Amino Acids↗

PubMedDate not supplied

Continuing professional development: does it make a difference?

Continuing professional development (CPD) is costly in terms of both organizational resources and personal time and effort. It forms an important part of the strategy for modernizing the health service and is an expectation of qualified nurses. There is little evidence to demonstrate the impact of CPD in terms of improved patient care and services. A small pilot study was undertaken. A group of intensive therapy unit (ITU) managers developed a goal attainment scale (GAS) to evaluate the impact of an ITU course. Results suggest that the ITU course did make a difference to the development of ITU nurses, but the nurses who did not take the course also developed. This has implications for service providers and educationalists in terms of expectations, timing and content of courses. The GAS was a useful tool as an approach to evaluating the impact of CPD but requires more rigorous testing before it can be described as reliable and valid.

Critical Care↗