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Biomedical subjects

G Bendixen

Publications and source records attributed to G Bendixen.

At least 19 recordsLinked to original sources
PubMed1997

Quantitative assessment of clinical disease status in primary Sjögren's syndrome. A cross-sectional study using a new classification model.

Quantitative and qualitative assessment of the clinical disease manifestations in 41 primary Sjögren's syndrome (pSS) patients was performed according to a new classification model. Frequencies of subgrouped disease manifestations were as follows: 1) surface exocrine disease: 100%, 2) internal organ exocrine disease: 63%, 3) monoclonal B lymphocyte disease: 5%, 4) inflammatory vascular disease: 71%, 5) non-inflammatory vascular disease: 59%, 6) mediator induced disease: 98%. Summary scores for severity of surface exocrine disease correlated to the summary scores of all other disease manifestations (p = 0.02), to the summary scores of internal organ exocrine disease (p = 0.003), and to the summary scores of mediator induced disease (p = 0.03). Blood leucocyte counts showed significant negative correlations to levels of plasma IgG, serum IgA-RF, IgM-RF, anti-SSA/SSB antibodies, IL-6, and IL-1Ra. We conclude that the model made detailed analysis of the clinical presentation of pSS possible, and thus may assist in elucidating important pathobiological aspect of the disease.

Adult↗
PubMed1996

A new model for classification of disease manifestations in primary Sjögren's syndrome: evaluation in a retrospective long-term study.

OBJECTIVES: The clinical features of 80 patients with primary Sjögren's syndrome (PSS) were revised in order to evaluate the descriptive and analytical facilities of a newly proposed model for classification of the exocrine and nonexocrine disease manifestations in PSS. DESIGN: Retrospective, long-term (median 7.5 years follow-up) observational, clinical study. SETTING: Patients were recruited from our Department, which is a tertiary referral centre for PSS patients. SUBJECTS: Eighty patients fulfilling the Copenhagen criteria for keratoconjunctivitis sicca and/or xerostomia and followed between 1972 and 1991 were studied. RESULTS: All patients had 'surface exocrine disease' and in 31% this was the only disease manifestation. 'Internal organ exocrine disease' was found in 25% of the patients, whilst 2.5% developed 'monoclonal B lymphocyte disease' (non-Hodgkin's lymphoma). 28% displayed 'inflammatory vascular disease', 25% 'noninflammatory vascular disease', 41% "mediator-induced disease' and 2.5% 'autoimmune endocrine disease' (thyroiditis). In patients with 'internal organ exocrine disease' the frequencies of "mediator-induced disease' (70%; P < 0.01) and 'inflammatory vascular disease, (50%; P < 0.03) were significantly higher than expected by chance. The level of immunoinflammatory activity (assessed by plasma IgG, serum ANA and focus scoring of minor labial salivary gland biopsies) correlated with the extent of clinical disease as assessed by the model. CONCLUSIONS: We conclude that this theoretically based model for classification of disease manifestations in PSS contains descriptive and analytic powers which may assist the clinical handling of these patients.

Aged↗
PubMed1995

Increased expression of complement receptor type 1 (CR1, CD35) on human peripheral blood T lymphocytes after polyclonal activation in vitro.

The receptor for C3b and C4b--complement receptor type 1 (CR1, CD35)--is present on a variety of cell types including erythrocytes, phagocytic cells, B lymphocytes and a small subpopulation of T lymphocytes. The function of the receptor varies according to the different cell types, but on T lymphocytes the function is as yet not known. The present study concerns the influence of polyclonal stimulation on CR1-expressing T lymphocytes. Incubation with PHA resulted in a dose-dependent increase in the number of CR1-positive T lymphocytes. The CR1-expression T lymphocytes were found in both the CD4- and the CD8-positive subpopulation, but a significant stimulatory increase was only found in the CD4-positive population. A significant increase in the number of CR1-expressing T lymphocytes was found when monocytes were present during stimulation, indicating an importance of monocytes and/or monocyte products. However, the increase was not regulated by arachidonic acid metabolites of the cyclo-oxygenase pathway as indomethacin failed to inhibit the increase. Neither did rIL-1 alpha, rIL-1 beta, rTNF alpha nor rIL-6 alter the number of CR1-expressing T lymphocytes. The results of this study indicate a role for CR1 on T lymphocytes in the regulation of the immune system.

Concanavalin A↗
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

Cytokines cause functional and structural damage to isolated islets of Langerhans.

Cytokines are soluble, antigen non-specific, non-immunoglobulin mediators produced and secreted by blood mononuclear cells interacting in the cellular immune-response. To test the possibility that cytokines participate in the autoimmune destruction of the pancreatic beta-cells leading to insulin-dependent diabetes mellitus, isolated human or rat islets of Langerhans were incubated for 7 days with cytokine-rich, cell-free supernatants of blood mononuclear cells from healthy human donors stimulated with or without purified protein derivative of tuberculin or phytohaemagglutinin. Glucose stimulated insulin-release, and contents of insulin and glucagon in islets incubated with cytokine-rich supernatants were markedly reduced. This impairment of islet function was due to a cytotoxic effect of cytokine-rich supernatants as judged by disintegration of normal light-microscopic morphology.

Animals↗
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↗