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K L Chang

Publications and source records attributed to K L Chang.

82 records · Page 5Linked to original sources
PubMed1989

Defective helper T cell function in IgM rheumatoid factor synthesis in patients with ankylosing spondylitis.

Despite chronic inflammation and the presence of hypergammaglobulinemia, rheumatoid factor (RF) is rarely found in the blood of patients with ankylosing spondylitis (AS). We used ELISA to compare spontaneous and pokeweed mitogen (PWM)-induced IgG, IgM and IgM rheumatoid factor (IgM-RF) production in normals and in patients with rheumatoid arthritis (RA) and AS. The IgG and IgM synthesis in these three groups did not differ. However, the IgM-RF level in PWM-induced mononuclear cell cultured supernatants of AS was significantly decreased, compared with normal and RA patients. Furthermore, mixing experiments by co-culture of normal T or B cells with patient's B or T cells in the presence of PWM revealed a deficiency of the helper T cell function in patients with AS. These results illustrate the cellular mechanism of the seronegativity of the rheumatoid factor in patients with ankylosing spondylitis.

Arthritis, Rheumatoid↗
PubMed1989

Defective phagocytosis, decreased tumour necrosis factor-alpha production, and lymphocyte hyporesponsiveness predispose patients with systemic lupus erythematosus to infections.

Twenty-three patients with systemic lupus erythematosus (SLE) were studied in order to understand the mechanism of increased susceptibility to infection in SLE patients. We found that phagocytosis by polymorphonuclear leucocytes (PMN) was significantly defective in untreated (24.2 +/- 3.1%) and immunosuppressant-treated SLE patients (30.0 +/- 3.6%) compared with normals (47.9 +/- 0.6%), while the generation of superoxide anion radicals was normal. The defective phagocytosis in SLE could be increased by human recombinant tumour necrosis factor alpha (TNF-alpha). However, the percentages of phagocytosis in SLE before and after TNF-alpha stimulation were 56.6% and 60.7% of the normal values. This indicates that certain populations of PMN in SLE are not only defective as regards phagocytosis but also unresponsive to TNF-alpha stimulation. In an ELISA, TNF-alpha production by phorbol myristate acetate (PMA)-stimulated mononuclear cells from SLE patients was significantly decreased (181.4 +/- 22.7 pg/ml vs. 533.0 +/- 81.9 pg/ml, p = 0.002). In addition, the percentage of phytohaemagglutinin (PHA)-stimulated mononuclear cells in S phase in the cell cycle was deficient in patients with SLE (17.2 +/- 1.8% vs. 29.7 +/- 2.9%, p less than 0.001). These results lead us to propose that defective PMN in spontaneous and TNF-alpha-induced phagocytosis, decreased production of TNF-alpha, and lymphocyte hyporesponsiveness predispose patients with SLE to infections.

Adolescent↗
PubMed1988

Purification of murine liver-derived inhibitory protein.

Murine liver-derived inhibitory protein (LIP) capable of inhibiting human lymphocyte proliferation was separated from liver extract. The steps of purification included ammonium sulfate precipitation, DEAE-cellulose and hydroxylapatite ion exchange chromatographies, and gel filtration. The purified LIP appeared to be highly homogeneous, as verified by polyacrylamide gel electrophoresis (PAGE) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). There was arginase activity in the LIP Preparation.

Ammonium Sulfate↗
PubMed1987

The effects of arginase on neoplasm. I. The role of arginase in the immunosuppressive effects of extract from gastric cancer.

Arginase, a potent immune inhibitor, is studied in gastric cancer for its possible role in immunosuppression. Aqueous extracts (n = 12) from gastric cancer tissue inhibited PHA-induced lymphocyte proliferation more than those from normal gastric mucosal tissues (p less than 0.05). The inhibition was not due to cytotoxic effect of the extracts. Gastric arginase was isolated from gastric extracts by an affinity column conjugated with an anti-arginase antibody. The arginase from both normal and cancer gastric tissues strongly inhibited lymphocyte proliferation. By using enzyme-immunoassay, the arginase contents in cancer tissues were determined and showed 3 times as much as that in normal gastric mucosal tissues (n = 14) (p less than 0.005). The increased arginase content in cancer tissue was further confirmed by immunohistochemistry study. Arginase exists abundantly amounts in the cytoplasm of cancer cells, much more than that of normal cells (n = 30). It is conceivable that the depressed cellular immunity in gastric cancer patients might be partly due to the abundant amount of arginase in cancer cells.

Arginase↗
PubMedDate not supplied

Serious suppurative group A beta-hemolytic streptococcal infection in previously well children: report of six cases.

Recently, among adults and children, an increase in the incidence of invasive disease caused by group A beta hemolytic streptococcus (GABHS) has been noted. From December 6, 1981 to January 19, 1991, we experienced six cases of serious infection caused by GABHS in previously well children. Among them, five cases were found in recent two years. The clinical manifestations were varied. One child had sepsis, one had streptococcal toxic shock-like syndrome, two had pyogenic arthritis, and the other two newborn infants had empyema and cellulitis associated with sepsis. Early diagnosis and treatment with appropriate antibiotic are necessary for a good outcome. In addition, empyema and pyoarthritis of the hip often need surgical drainage.

Arthritis, Infectious↗