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Biomedical subjects

A Sidgwick

Publications and source records attributed to A Sidgwick.

7 recordsLinked to original sources
PubMed1991

The use of paramagnetic beads for the detection of major histocompatibility complex class I and class II antigens.

Specific immunoadsorbents were prepared using paramagnetic particles (Dynabeads), and their ability to immunoprecipitate major histocompatibility complex (MHC) Class I and Class II antigens compared with conventional protein A Sepharose immunoadsorbents. Lysates of lymphoblastoid cells provided the antigen source which were visualized by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Dynabeads were found to be as effective as protein A Sepharose immunoadsorbents at immunoprecipitating MHC Class I and Class II antigens, but had a much lower nonspecific binding capacity resulting in fewer interference bands and lower backgrounds.

Cells, Cultured↗
PubMed1985

A simple, rapid, reliable reverse haemolytic plaque assay and positive quality control test for routine use.

A simple, rapid, reliable protein A reverse haemolytic plaque assay is described. Monolayers of protein A-coupled sheep red blood cells, in liquid medium, are formed in shallow 15 mm diameter chambers of the type commercially available for leucocyte migration inhibition assays. No agarose is necessary and the chambers are quick and easy to use, economical of reagents, and of a constant size and volume. Results compare favourably with those obtained using Cunningham chambers. The assay is ideal for clinical studies in which large numbers of samples are assayed daily. A positive quality control test for the protein A reverse hemolytic plaque assays is described. Spleen cells are stimulated with pokeweed mitogen to give high numbers of secreting cells. The cells are harvested on day 6 of culture and stored in aliquots at -70 degrees C. When thawed and tested in the protein A assay, these secreting cells form a sensitive and reproducible monitor of the day-to-day performance of the assay. Variation between operators and between batches of reagents may also be checked if desired, with little additional time, effort or expense.

Animals↗
PubMed1983

Genetic control of progressive autonomic failure: evidence for an association with an HLA antigen.

In 16 patients with progressive autonomic failure, a rare disease of unknown cause, the frequency of the HLA antigen Aw32 was 13 times more common than in healthy controls, giving a relative risk of progressive autonomic failure with Aw32 of 28.7. Such genetic predisposition to the disease might cause a defect of catecholamine metabolism In the brain or possibly affect the immune response to a virus.

Autonomic Nervous System Diseases↗
PubMed1983

Skin biopsies in relatives of patients with dermatitis herpetiformis.

Out of 109 patients with dermatitis herpetiformis (DH) only one was known to have a first-degree relative with the disease. This is in keeping with previous reports that the familial incidence of DH is low. Study of the family in which two siblings were affected showed both to have HLA-B9 whereas a third, unaffected sibling did not have this antigen. This finding supports the view that both genetic and environmental factors are involved in the pathogenesis of DH, 20 first-degree relatives of 10 other patients with DH had skin biopsies examined by immunofluorescence for the presence of IgA, but none proved positive.

Adolescent↗
PubMed1982

Linear IgA disease in adults.

A multi-centre study is described in which thirty-five adult patients with papillary IgA dermatitis herpetiformis (DH) were compared with forty-two patients with linear IgA deposits, of whom thirty-four had homogeneous-linear (HL) and eight had granular-linear (GL) IgA deposits. The three groups were similar with regard to age of onset, presence of circulating immune complexes and auto-antibodies, incidence of spontaneous remission, histology of lesional skin and response to dapsone. There was a female predominance in the HL group in contrast to the male predominance in the other two. It was not possible to diagnose the HL group clinically. Some patients had a rash typical of DH whilst others resembled pemphigoid. In the majority, however, no specific diagnosis could be made with confidence. The GL group clinically resembled the DH group. The incidence of positive potassium iodide patch tests was greater in the DH group than in the other two. An associated enteropathy was found in 24% of patients in the HL group, 30% of patients in the GL group and 85% of patients in the DH group. Fifty-six percent of HL patients had HLA-B8 compared with 50% in the GL group and 88% in the DH group. Patients with linear IgA deposits may not be a uniform group, but until they can be divided into specific subgroups (e.g. by ultrastructural localization of the deposit or by response to a gluten-free diet) we propose that the term adult linear IgA diseases should be used to distinguish these patients from those with papillary IgA deposits.

Adolescent↗