Biomedical subjects

G Barden

Publications and source records attributed to G Barden.

5 recordsLinked to original sources

PubMed1992

Human monoclonal antibodies specific for blood group antigens demonstrate multispecific properties characteristic of natural autoantibodies.

A panel of 72 human monoclonal antibodies with specificities for blood group antigens, A, Rh D, Rh C, Rh c, Rh E, Rh e, Rh G, Jka and Jkb, has been established from the peripheral blood of deliberately immunized donors. Previous work has established that the antibodies are highly specific for their respective blood group antigens, and a number of them are in routine clinical use as blood grouping reagents. This panel was screened for reactivity against six unrelated foreign and autoantigens by ELISA, for rheumatoid factor activity by ELISA and agglutination techniques, and for reactivity with a number of different tissues by immunofluorescence. Binding of the monoclonal antibodies to unrelated exo- and autoantigens was commonly seen amongst the antibodies of the IgM class, and to a lesser degree amongst the IgG class, with reaction patterns similar to those given by natural autoantibodies. Only five of the IgM antibodies failed to demonstrate any unexpected cross-reactivities and these included 1/13 anti-D, 2/7 anti-E, 1/13 anti-c and 1/2 anti-A. We propose that rather than natural autoantibodies representing a distinct population of immunoglobulins, multispecificity (polyspecificity, or polyreactivity) may be a feature of antibodies produced in response to exogenous antigens. The implications of this for the study of autoantibodies are discussed.

Antibodies, Monoclonal↗

PubMed1991

Human monoclonal antibodies against blood group antigens preferentially express a VH4-21 variable region gene-associated epitope.

An anti-idiotypic antibody has been raised which recognizes human immunoglobulins with cold agglutinin activity of anti-I/i specificity. The pattern of reactivity of the antibody indicates that the structural basis for the epitope is located in the VH4-21 gene segment of the VHIV family, which is preferentially utilized by these cold reactive antibodies. Using this antibody, epitope expression was investigated in a panel of 72 human monoclonal allo-antibodies specific for human blood group antigens, as compared with a control panel of 39 randomly selected human monoclonal IgM antibodies of unknown specificities. The anti-blood group panel included 44 IgM and 28 IgG monoclonal antibodies against a variety of blood group antigens including the A antigen, Rh C, c, D, E, e, G antigens, and the Kidd antigens Jka and Jkb. The epitope was expressed by 64% (28/44) of the IgM anti-blood group antibodies and by 21% (6/28) of the IgG antibodies, but by only 7.7% (3/39) of the control IgM antibodies. These data indicate that the human alloimmune response to blood group antigens is biased in the use of VH gene families, with a preference for the VH4-21 gene segment of the VHIV family, or closely related gene segments. The fact that this mirrors the findings for the autoimmune cold agglutinins suggests a link in immunoglobulin gene usage between antibodies against structurally diverse antigens on the red cell surface.

Antibodies, Monoclonal↗

PubMed1976

Polymicrobic bacteriuria: significant association with bacteremia.

Current clinical practice states that a urine culture yielding three or more isolates must be considered a contaminated specimen and discarded. The validity of this practice was tested by reviewing all patients at the West Haven Veterans Administration Hospital with positive blood cultures for 1 year to determine how many were associated with polymicrobic bacteriuria (two or more urine isolates each present at greater than 10(5) colonies/ml). During 1973 there were 18 patients who had bacteremia associated with a urinary tract infection in which the same organism with the identical antibiogram was found in both the blood and the urine of these 18 patients with monomicrobic bacteremia 11(61%) had polymicrobic bacteriuria, with a mean of an additional 1.75 urinary pathogens present in significant quantities. In these patients with polymicrobic bacteriuria, an indwelling bladder catheter was present for a mean period of 4.4 months before the episode of bacteremia. Only 5 of the 11 patients with polymicrobic bacteriuria had temporally associated urinary tract manipulation. Monomicrobic bacteriuria occurred in seven patients (39%). The mean indwelling bladder catheter time was 0.9 days, and urinary tract manipulation near the time of bacteremia occurred in all seven patients. Prospectively, nine other patients with polymicrobic bacteriuria were recultured by one of us to be certain that appropriate collection and transportation methods were used; the presence of polymicrobic bacteriuria was repeatedly demonstrated in 7(78%). This study illustrates the clinical importance of polymicrobic bacteriuria.

Aged↗

PubMed1976

Endemicity of multiple staphylococcal phage types: relation of two common source outbreaks.

An outbreak of Staphylococcus aureus bacteremia occurred among patients treated in the hemodialysis unit in 1971. A second outbreak of S. aureus peritonitis occurred in 1973 in patients with chronic indwelling peritoneal catheters cared for together in the medial intensive care unit. Although the attending personnel, patients, and geographical locations were different in each outbreak, the following similarities were notes: (1) more than one phage type was epidemic: (2) an exogenous mode of spread with cross-contamination between personnel and patient as well as between patient and patient, and (3) breaks in sterile technique when handling the arteriovenous shunt site or the peritoneal catheter were made without the staff conducting the procedure being aware of their occurrence. Culture surveys of the same phage types found during the two epidemics. Thus, an endemic reservoir of several different staphylococcal phage types was present. Careful, consistent application of aseptic technique when handling either arteriovenous shunts or peritoneal catheters and hand washing in between patients was required to prevent the endemic strains from becoming epidemic.

Asepsis↗

PubMed1975

The role of the nurse epidemiologist in infection control and continuing education.

A university affiliated Veterans Administration Hospital had an increase in the number of serratia isolates. An epidemiologic investigation, including personnel and environmental prevalence study, helped correct errors in technique, management and judgment. A nurse epidemiologist prevented a cluster of infections from becoming an epidemic.

Connecticut↗