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Biomedical subjects

D Voak

Publications and source records attributed to D Voak.

At least 73 records · Page 4Linked to original sources

Quantitation of antibody binding to erythrocytes in LISS.

The amount of antibody bound to cells in a low ionic strength solution (LISS) has been quantitated for several antibodies including anti-D, anti-c, anti-Kell, anti-Fya, and anti-Jka. With the exception of the Kell antibodies there was an enhancement of the rate of antibody uptake in LISS. For Rh antibodies the amount bound after a 5-min LISS incubation is comparable to that bound after 45 min in saline. For Kell antibodies a smaller amount was bound in LISS than in saline. The effect of the ratio of serum to cells was also studied, and with several antibodies there was an increase in the amount of antibody bound with a higher serum to cell ratio irrespective of suspending medium. For Kell antibodies this ratio appears to be of greater importance than the ionic strength for antibody detection. A modification to the LISS method to increase the serum to cell ratio is, therefore, presented.

Antigen-Antibody Complex↗

Use of monoclonal anti-C3 antibodies to characterise the fragments of C3 that are found on erythrocytes.

Using monoclonal antibodies to C3 it has been shown that the red blood cells of patients with cold haemagglutinin disease carry on their cells C3d,g (alpha-2D-globulin) rather than C3d. C3d,g seems to be the final product of in vivo C3 activation in fluid phase and on red cells. The cleavage of C3dg to C3d and C3g does not appear to occur in vivo either in the fluid phase or on red cell bound C3bi. In vitro C3-coated red cells prepared by antibody or low ionic strength techniques produce cells with C3d and C3bi as the predominant C3 fragment, whereas the Fruitstone technique in which coating occurs by the alternative pathway has principally C3b. The activity of C3 cleaving enzymes in whole serum is strongly influenced by the ionic conditions of the serum.

Anemia, Hemolytic, Autoimmune↗

A simple method for detecting complement-fixation by autologous platelets in autoimmune thrombocytopenic purpura.

A new modification of the microtitre complement fixation test, (CFT), is described for the detection of platelet-bound antibodies (PBA). The test was positive in 12 out of 16 patients, (75%), with active autoimmune thrombocytopenic purpura (AITP). It was negative in four patients who were in remission of AITP when tested, in 10 patients with non-immune thrombocytopenia and in 51 normal blood donors. This is a semi-quantitative method in which suspensions of the patients' own platelets consume complement and therefore prevent the lysis of sensitised sheep red cells (SRBC). Sera from some of these cases were also tested for serum anti-platelet antibody (SPA) and immune complexes. The possible mechanisms and the relevance of positive results are discussed.

Adenosine Diphosphate↗

Monoclonal anti-A from a hybrid-myeloma: evaluating as a blood grouping reagent.

A monoclonal anti-A antibody has been evaluated and found suitable for use as a potent routine ABO grouping reagent, without the use of additives. The IgM anti-A (MH2/6D4) is secreted into the tissue culture supernatant by a permanent line of cloned cells derived by fusion of anti-A producing spleen cells and a mouse myeloma cell line. This is a cost-effective reagent which should reduce production costs by over 50%. This reagent has the advantages inherent in monoclonal antibodies among them the availability of unlimited quantities of unvarying antibody of known properties.

ABO Blood-Group System↗

Association of polymyalgia rheumatica and giant-cell arteritis with HLA-B8.

Histocompatibility antigens were determined in 30 patients with temporal arteritis, 27 patients with polymyalgia rheumatica, and 216 normal blood donors. HLA-B8 was significantly more common in patients with polymyalgia rheumatica (59%) and temporal arteritis (50%) than in the controls (27%). The findings of HLA-A10 in 26% of the patients with polymyalgia rheumatica compared with only 10% of the controls may be associated with the suggested immunological pathogenesis of the condition.

Female↗

HLA-B27 and frozen shoulder.

Histocompatibility antigens were determined in 38 patients with frozen shoulder and 216 normal blood-donors. HLA-B27 was significantly more common in patients with frozen shoulder (42%) than in the controls (10%). The distribution of the other 19 histocompatibility antigens was similar in the patient and control groups. This result may be associated with the suggested immunological pathogenesis of the condition.

Adult↗

Improved antibody detection by the use of range expansion and longer filter wavelength in a low ionic strength-protamine sulphate Auto-Analyzer system.

Range expansion, achieved by insertion of a variable resistance between the colorimeter and the recorder together with the use of 550 nm colorimeter filters, has resulted in markedly improved sensitivity for antibody detection, and improved sample identification, in a low ionic strength-protamine sulphate (LISPS) system. Range expansion also permits a lower concentration of red cells to be used, thus economizing on fully typed cells. Glycerol stored frozen cells were found to be only slightly less sensitive than fresh cells in this system.

Antibodies↗

HLA antigens in pernicious anaemia.

The increased frequency of HLA-B7 alone and HLA-A3/B7 together, in the same patient, has been confirmed in pernicious anaemia. There is no increase prevalence of HLA-A3 alone. No association has been found between the presence of serum intrinsic factor type 1 antibody and HLA-A3 or HLA-B7.

Anemia, Pernicious↗