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Biomedical subjects

J Hassan

Publications and source records attributed to J Hassan.

46 records · Page 3Linked to original sources
PubMed1989

Rheumatoid factors in cystic fibrosis: associations with disease manifestations and recurrent bacterial infections.

Serum IgM and IgA rheumatoid factor (RF) levels were measured by ELISA in 71 adolescent and adult patients with cystic fibrosis (CF) and 69 control subjects. IgM RF values from 15 (21%) CF patients greater than 2 s.d. of control subjects (P less than 0.001). Elevated IgM RF values were significantly associated with worse spirometric measurements of pulmonary function (P less than 0.01) and with more frequent exacerbations of respiratory tract infection (P less than 0.001). A characteristic episodic arthropathy occurred in 27% of IgM RF positive patients, compared with 4% of IgM RF negative patients (P = 0.015). IgA RF values from 26 (37%) CF patients were elevated (P less than 0.001). Pulmonary function was significantly worse in patients with elevated IgA RF values (P less than 0.001). However, IgA RF was not associated with exacerbations of respiratory tract infection or episodic arthropathy. Both IgM and IgA RF values correlated significantly with their corresponding Ig levels, suggesting that RF synthesis was the result of polyclonal B cell activation. It is concluded that serum IgM RF values in CF are associated with worse lung disease and recurring bacterial antigenic stimulation. IgM RF may contribute to the development of arthropathy in some patients. Induction of IgA RF synthesis and its pathogenic potential may differ from IgM RF.

Adolescent↗
PubMed1988

Antibodies to Proteus in rheumatoid arthritis.

Increased levels of Proteus antibodies were found in patients with rheumatoid arthritis and coeliac disease, when compared to normal controls or patients with SLE and sarcoidosis.

Antibodies, Bacterial↗
PubMed1987

Characterization and quantification of solubilised HLA-DR antigens from circulating human monocytes using an immunoblotting procedure.

An immunoblotting technique was modified to detect and biochemically characterize HLA-DR antigens expressed on circulating human monocytes. Membrane proteins of peripheral blood monocytes were solubilised using the mildly anionic detergent, sodium deoxycholate. These solubilised proteins were resolved by SDS-PAGE and transferred electrophoretically to nitrocellulose. The HLA-DR antigen was detected using a polyclonal antiserum and two monoclonal anti-HLA-DR antibodies. Both immunoperoxidase and 125I autoradiography techniques were used for visualisation of the antigen. The resolution of HLA-DR reactive material was increased when proteins were renatured with 4M urea after blotting. Immunoprobing of a sample of solubilized membrane proteins showed three bands of HLA-DR antigenic reactivity at molecular weights 65kDa, 55kDa and 46kDa. After storage at -70 degrees C for 2 months, only the 46kDa HLA-DR antigen band was detectable. Nonetheless, the 2-chain HLA-DR molecule was found to be an extremely stable complex which could not be dissociated by boiling in sample buffer containing 5% 2-mercaptoethanol and 2% SDS. A stronger reducing agent, 25 mM dithiothreitol, was required to split the HLA-DR molecule into its alpha and beta subunit chains. Finally, in a study of circulating monocytes from normal subjects, the immunoblotting technique was shown to quantitate solubilised HLA-DR antigen in a reproducible manner.

Electrophoresis, Polyacrylamide Gel↗
PubMed1986

Lymphoid irradiation in intractable rheumatoid arthritis. A double-blind, randomized study comparing 750-rad treatment with 2,000-rad treatment.

Twenty patients with intractable rheumatoid arthritis were treated with 750-rad or 2,000-rad lymphoid irradiation in a randomized double-blind comparative study. Over a 12-month followup period, there was a significant improvement in 4 of 7 and 6 of 7 standard parameters of disease activity following treatment with 750 rads and 2,000 rads, respectively. Transient, short-term toxicity was less frequent with the lower dose. In both groups, there was a sustained peripheral blood lymphopenia, a selective depletion of T helper (Leu-3a+) lymphocytes, and reduced in vitro mitogen responses. These changes did not occur, however, in synovial fluid. These results suggest that 750-rad lymphoid irradiation is as effective as, but less toxic than, that with 2,000 rads in the management of patients with intractable rheumatoid arthritis.

Adult↗
PubMed1986

Effects of gold therapy on the synthesis and quantity of serum and synovial fluid IgM, IgG, and IgA rheumatoid factors in rheumatoid arthritis patients.

Eleven patients with active rheumatoid arthritis were monitored prospectively while receiving up to 1 gm of gold sodium thiomalate. There was a significant decrease in serum and synovial fluid IgG, IgA, and IgM rheumatoid factor (RF) levels over the period of study. Comparison of changes in serum RF and total immunoglobulin levels indicated a selective effect on RF production. These observations were supported by changes in the spontaneous in vitro production of IgM-RF and total IgM by peripheral blood mononuclear cells. Studies of synovial membrane synthesis showed a downward trend in immunoglobulin and RF production, but this did not reach statistical significance. A differential effect on the various RF classes was also noted. The most profound effect was on IgM-RF production; whereas, changes in IgG-RF production were least affected. These results suggest a selective and differential effect of gold salts on RF production.

Adult↗
PubMed1986

The immunological consequences of gold therapy: a prospective study in patients with rheumatoid arthritis.

Gold sodium thiomalate (GST) is known to modify the disease process in patients with active rheumatoid arthritis (RA). To help understand the mechanism of action of GST, several immunological parameters were prospectively evaluated in 10 patients with active RA following the introduction of gold therapy. Before therapy, absolute numbers of peripheral blood T suppressor/cytotoxic lymphocytes were significantly depressed (P less than 0.01) and a raised T helper/T suppressor cell ratio was found. After 1 g of GST, an absolute reduction in total lymphocyte numbers including HLA/DR positive mononuclear cells, was evident (P less than 0.01). This lymphopenic effect was not selective for a single population since the proportions of T cells, T cell subsets and B cells remained unchanged. Lymphocyte function was also examined. Raised in vitro production of IgG (P less than 0.01) and IgA (P less than 0.05) was found before therapy. After GST, in vitro immunoglobulin synthesis was reduced and this was significant with respect to the IgM (P less than 0.001) and IgA (P less than 0.01) isotypes. Similarly, a parallel reduction in serum immunoglobulin levels developed. GST therapy was also associated with a reduced proliferative response to phytohaemagglutinin, concanavalin A and pokeweed mitogen in the initial phase of gold administration. The significant finding in this study suggest that the in vivo immunosuppressive effect of GST is explained not only by impaired mononuclear cell function but also by a significant reduction in T and B lymphocyte numbers.

Arthritis, Rheumatoid↗
PubMed1985

Lymphoid irradiation in intractable rheumatoid arthritis: effects on the production of immunoglobulins and rheumatoid factors.

Changes in the production of immunoglobulins and rheumatoid factors (RF's) were studied in 20 patients with intractable rheumatoid arthritis (RA) following total doses of 750 rad or 2,000 rad lymphoid irradiation. Over a 12 month follow up period there was no consistent change in absolute serum or synovial fluid levels, or in synovial membrane production of either total IgG, IgA or IgM, or the corresponding RF fractions. The invitro production of immunoglobulins and IgM RF by peripheral blood mononuclear cells was also unaltered, except for one patient who had a dramatic rise in IgM RF production. Over the same period there was a significant overall reduction in disease activity following both doses of radiotherapy. It is concluded that the clinical response which occurs following lymphoid irradiation is not due to a reduction in RF production. Furthermore, the production of RF's appears to be unaffected by the changes in T cell immunity which occur following lymphoid irradiation.

Arthritis, Rheumatoid↗