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Biomedical subjects

G Bendixen

Publications and source records attributed to G Bendixen.

At least 19 recordsLinked to original sources
PubMed1991

[Systemic lupus erythematosus. 1. Disease manifestations, infections, thrombotic episodes, causes of death and survival in a case load of 173 patients followed for 13.9 years].

One hundred and seventy-three patients had systemic lupus erythematosus according to the 1982-ARA-criteria. The mean disease duration at the time of the study was 16.4 years, and the patients were followed by three Copenhagen clinics for a mean of 13.9 years until 1987/88 or death. Half of the patients had nephropathy, 61 patients developed severe infections, and 39 patients had thrombotic episodes. Fifty-six patients died during the observation period, 24 due to active lupus (12 of kidney failure), 12 because of infections, and 11 because of atherosclerotic cardio-vascular disease. The patients had 10-, 15- and 20-year survival rates of 80, 65 and 48 per cent. The deaths were evenly distributed throughout the observation period.

Adult↗
PubMed1991

[Systemic lupus erythematosus. 2. Factors of predictive significance for survival].

Sixty-one of 173 patients with systemic lupus erythematosus followed for a mean of 13.9 years had severe infections which influenced their survival more than could be accounted for by the mortality (20 per cent) caused by the infections. Patients with infections had more SLE manifestations than patients without infections, and they died of lupus manifestations more often than patients without infections. Patients who went into a permanent remission and patients who died of lupus differed most markedly by the rates of infection. The rate of infection was increased more than tenfold in patients treated with high dosages of glucocorticoid compared with patients who received low dosages. Treatment with cytostatics influenced the rate of infections to a moderate degree. Nephropathy also influenced survival but half of the patients with nephropathy maintained a normal plasma creatinine in spite of the long observation period. 16 per cent of the patients with nephropathy died of kidney failure or are receiving chronic hemodialysis.

Adult↗
PubMed1991

Complement receptor type 1 (CR1, CD35) expression on peripheral T lymphocytes: both CD4- and CD8-positive cells express CR1.

T lymphocytes from 42 healthy blood donors were examined for expression of CR1 on the cell surface using a fluorescence-activated cell sorter. The fraction of CR1-positive T lymphocytes varied in the range from 1 to 8% (median 2.4%). The CR1-positive T lymphocytes constituted a homogeneous group of cells regarding both size and granulation; they seemed to be larger and more granulated than the average T lymphocytes. The CR1-expressing T lymphocytes were found both in the CD4- and in the CD8-positive subpopulations of T lymphocytes, and although the CD4-positive cells expressed CR1 with a slightly higher percentage than did the CD8-positive cells, this difference was not significant. The number of CR1-positive T lymphocytes did not correlate with the level of CR1 on erythrocytes. The presence of CR1 on a small T lymphocyte population suggests that CR1 on T lymphocytes might play a role in the immune regulation.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1988

Modulation of natural killer cell activity in peripheral blood by physical exercise.

The present study was designed to examine the effect of physical exercise on human natural killer (NK) cells. Six healthy volunteers underwent two different acute physical exercise tests with an interval of at least 1 week: (1) 60 min bicycle exercise at 80% of maximal oxygen uptake (VO2max) and (2) 60 min back-muscle training at up to 29% of VO2max; blood samples were collected before and during the last few minutes of exercise, as well as 2 h and 24 h afterwards. The NK cell activity (lysis/fixed number of mononuclear cells) increased during bicycle exercise, dropped to a minimum 2 h later and returned to pre-exercise levels within 24 h. Back-muscle exercise did not significantly influence NK cell activity. Plasma levels of adrenaline, noradrenaline, and cortisol were elevated during bicycling, but not during back-muscle exercise, indicating that exercise intensity is a determinant of NK cell activity. During bicycle exercise the NK cell subset (CD16- cells) of mononuclear cells increased significantly. Furthermore an improved interleukin 2 (IL-2) boosting of the NK cell activity was found during work as compared to IFN-alpha and indomethacin-enhanced NK cell activity. These results indicate that NK cells with a high IL-2 response capacity are recruited to the peripheral blood during exercise. The decreased NK cell activity demonstrated 2 h after work was probably not due to fluctuations in size of the NK cell pool, since the proportion of CD16+ cells was normal. The finding that indomethacin fully restored the suppressed NK cell activity in vitro and the demonstration of a twofold increase in monocyte (CD20+ cells) proportions 2 h after work, strongly indicate that prostaglandins released by monocytes during the heavy physical exercise are responsible for the down-regulation of the NK cells.

Adult↗
PubMed1986

Erythrocyte CR1 determination using monoclonal antibody in a microtiter plate ELISA; receptors are not masked by immune complexes.

The microtiter plate ELISA using monoclonal antibody is a specific, sensitive and quantitative technique for measuring CR1 on human erythrocytes. The present investigations established that receptor occupancy by immune complexes did not affect the measurements. The monoclonal anti-CR1 antibody To5 bound unimpeded to receptors that had reacted with an excess of complement-opsonized tetanus toxoid anti-tetanus toxoid complexes prepared at antigen:antibody ratios between 32:1 and 1:8. The CR1 levels on erythrocytes from 11 patients with systemic lupus erythematosus (SLE) were not increased (P greater than 0.30) after release of CR1-bound immune complexes by incubation with factor I. Neither did the serum from these patients contain blocking anti-CR1 activity (P greater than 0.10). Additionally, the number of antigenic CR1 sites in 10 normals and in the 11 patients with SLE was well correlated with the number of functional receptor sites as assessed by binding of soluble complexes (P less than 0.001). These data establish that the true CR1 levels are determined using the microtiter plate ELISA for quantitation of CR1 in patients with diseases involving immune complexes and/or autoantibodies.

Antibodies, Monoclonal↗
PubMed1986

Release of immune complexes bound to CR1 on erythrocytes; suramin inhibits factor I in the presence of EDTA.

An experimental model was established in order to study the release of immune complexes (IC) bound by complement C3b receptors (CR1) on human erythrocytes (RBC). Soluble tetanus toxoid anti-tetanus toxoid complexes were incubated with RBC in the presence of autologous serum at optimal conditions for binding. The RBC carrying complement-opsonized complexes were incubated with appropriate serum reagents, and it was shown that factor I was required for release of the complexes, which occurred without loss of CR1. Suramin was, irrespective of factor I, found to induce release of CR1-bound IC in the absence of EDTA, whereas factor I-mediated release was inhibited by suramin in the presence of EDTA. EDTA probably interfered through a charge-dependent interaction. These observations are decisive for the interpretation of in vitro experiments involving these reagents. The combination of EDTA and suramin was found inappropriate for use in quantitative determination of in vivo CR1-bound IC.

Antigen-Antibody Complex↗
PubMed1985

A microtiter plate enzyme-linked immunosorbent assay for measuring C3b receptors on human erythrocytes.

An enzyme-linked immunosorbent assay was developed for quantitation of complement C3b receptors (C3bR) on human erythrocytes fixed in monolayer to microtiter plates. The disadvantages of macro test tube systems (large consumption of sample material and reagents, tedious washing procedures, cell loss and hemolysis) were avoided, and the fixed cells could be stored. In return a modest reduction in antigenicity induced by glutaraldehyde was inevitable. The calibration curve expressed a detection limit of about 10% and discrimination between levels of C3bR in the interval of about 10-120% of a standard erythrocyte with a high uptake of anti-C3b-receptor antibodies. The determinations of C3bR in normals as well as in patients varied within these limits, and showed a preponderance of low levels in the patients. The between-day coefficient of variation was 10.3%; the within-assay interplate and intraplate determinations respectively gave coefficients of variation of 9.7% and 6.2%. The method is suitable for further development and use for investigation of erythrocyte-bound immune complexes.

Antibodies, Monoclonal↗
PubMed1985

Detection of antibody against extractable nuclear antigen by an enzyme-linked immuno-sorbent assay. Results from patients with rheumatic and internal medical diseases.

Anti-ENA antibody determination by ELISA technique may offer a valuable diagnostic help in the discrimination of patients with mixed connective tissue disease (MCTD) from those with other chronic inflammatory connective tissue diseases. Determination of this antibody was performed in a prospective designed investigation among 101 blood donors, 154 patients with various non-rheumatic internal medical diseases, and 229 patients with chronic inflammatory connective tissue diseases, including five patients with MCTD. A positive titre of anti-ENA antibody was found in approximately 10% of blood donors and patients with various internal medical disorders. A highly positive anti-ribonucleoprotein (RNP) titre was found in the patients with MCTD, but was also observed in patients with other chronic inflammatory connective tissue diseases, giving a predictive value of 56% for MCTD. We conclude that highly positive anti-RNP antibody values do not automatically indicate the diagnosis MCTD. Other diagnostic possibilities should still be considered.

Adult↗
PubMed1979

Systemic lupus erythematosus--a zoonosis?

The medical history was obtained and a physical examination carried out--in addition to an immunological investigation of the blood and skin--on 11 dogs in the ownership of patients with systemic lupus erythematosus (SLE). The results were compared with those obtained from a control group and it was found that they do not support the hypothesis that SLE is a zoonosis.

Animals↗