Systemic lupus erythematosus in South African blacks: prospective study.

BACKGROUND: The aim of the study was to evaluate clinical and laboratory findings in black South African patients with systemic lupus erythematosus (SLE) and to compare these with findings in a group of white patients. MATERIALS AND METHODS: Forty black patients were studied. The group of exclusively white patients reported by Beutner et al. was used for comparison. RESULTS: A decreased frequency of malar rash, photosensitivity, and hematologic involvement was found in black patients. They had anti-Sm and anti-nRNP antibodies and low complement more often than white patients with SLE in Beutner et al. group. CONCLUSIONS: More differences have been noted in laboratory than in clinical parameters and findings reported in African-Americans with SLE have been confirmed in black Africans. Ethnic factors may play a role in the symptomatology of SLE.

Health effects of passive smoking in adolescent children.

OBJECTIVE AND DESIGN: To study the effects of passive smoking on health in adolescent schoolchildren by questionnaire, spirometry and laboratory investigations. SETTING: Two schools in the Vanderbijlpark area. PARTICIPANTS: Seven hundred and twenty-six high-school children of average age 16 years. OUTCOME MEASURES: Lung function, serological abnormality or historical (i.e. questionnaire) evidence of ill health. RESULTS: The prevalence of respiratory illness before and after 2 years, respiratory symptoms, earache over the past year, low birth weight and learning difficulties were found to be significantly increased in the children exposed to parenteral smoke in the home, especially those exposed to maternal smoking. Spirometric and laboratory parameters, however, were not affected by passive smoking.

Measurement of anti-acetylcholine receptor auto-antibodies in myasthenia gravis.

Two different acetylcholine receptor (AChR) preparations derived from amputated human muscle (AChRAMP) and from the human rhabdomyosarcoma cell line TE671 (AChRTE671) were compared in radio-immunoprecipitation assays for the detection of AChR auto-antibodies in serum specimens from 20 patients with proven myasthenia gravis. Tests performed with the AChRTE671 and AChRAMP antigen preparations were positive in all the patients and in 19/20 respectively. A high degree of correlation (r = 0.94) was evident between the two auto-antigen preparations. Assays based on the use of TE671-derived antigen represent a useful alternative to the conventional assay using AChRAMP for the detection of AChR auto-antibodies.

Vitamin E, pulmonary functions, and phagocyte-mediated oxidative stress in smokers and nonsmokers.

Relationships among the plasma levels of vitamin E (VE), the numbers and prooxidative activities of circulating phagocytes, serum alpha-1-protease inhibitor (API), and pulmonary functions were investigated in 83 asymptomatic male cigarette smokers and 65 nonsmoking controls. Plasma levels of VE, of cholesterol, and of API were measured using high performance liquid chromatography, spectrophotometry, and nephelometry, respectively, whereas reactive oxidant (ROS) generation by activated blood phagocytes was measured using a whole blood luciginen-enhanced chemiluminescence method. Smoking was associated with significantly increased circulating neutrophil counts (p 0.0001), serum API (p 0.0001) and phagocyte-derived ROS-generation (p 0.0001), and decreased spirometric values (FEV1: p 0.0138 and FEF25-75: p 0.0654). Plasma VE and cholesterol levels were not significantly different between smokers and nonsmokers. However, in smokers both plasma VE and cholesterol correlated significantly and positively with serum API (r 0.24, p 0.03 and r 0.30, p 0.005, respectively), neutrophil counts (r 0.24, p 0.03 and r 0.25, p 0.03, respectively), and phagocyte-derived ROS-generation (r 0.32, p 0.003 and r 0.32, p 0.003, respectively), and significantly and inversely with FEV1 (r -0.23, p 0.03 and r -0.22, p 0.04, respectively) and FEF25-75 (r -0.32, p 0.003 and r -0.26, p 0.02, respectively). In nonsmokers plasma VE, but not cholesterol, was positively correlated with FEV1 (r 0.34, p 0.007) and FEF25-75 (r 0.40, p 0.001). The results suggest that VE protects the lungs of both smokers and nonsmokers and may act as a mobilizable antioxidant in response to smoking-induced oxidative stress.

NADPH-oxidase activity of stimulated neutrophils is markedly increased by serum.

In this study we have investigated the effects of serum (10, 20, and 40% final concentrations) on the activity of NADPH-oxidase and energy metabolism of activated human neutrophils in vitro. Neutrophils were stimulated with FMLP, PMA, or opsonized zymosan in the presence and absence of serum, and generation of reactive oxidants by intact cells was measured using lucigenin-enhanced chemiluminescence (LECL). This method was also used to measure NADPH-oxidase activity in purified membrane preparations from neutrophils activated with PMA in the presence or absence of serum. Cellular ATP levels and activities of the various glycolytic enzymes were assayed using CL and spectrophotometric procedures, respectively. Inclusion of serum with neutrophils during exposure to the various stimuli of membrane-associated oxidative metabolism caused significant enhancement of the LECL responses of intact cells as well as of the activity of NADPH-oxidase in purified membranes prepared from PMA-activated neutrophils. In the absence of serum, the ATP levels and activity of glyceraldehyde-3-phosphate dehydrogenase (G3PDH), but not the other glycolytic enzymes, were decreased in activated neutrophils, while inclusion of serum preserved neutrophil ATP levels and activity of G3PDH. Serum supplementation of the cell-suspending medium appears to promote optimum activity of NADPH-oxidase in stimulated neutrophils by preventing premature, oxidative inactivation of cellular energy metabolism.