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Biomedical subjects

V Andersen

Publications and source records attributed to V Andersen.

At least 91 records · Page 5Linked to original sources
PubMed1988

A haemolytic plaque forming assay for identifying cells producing anti-DNA antibodies.

A murine hybridoma cell line (aDNA35I9) secreting anti-DNA antibodies was used as a model for haemolytic plaque forming cells in an assay where DNA-conjugated sheep red blood cells (DNA-SRBC) were used as target cells. DEAE-dextran, employed to abolish the anti-complementary activity of agar gel, completely inhibited anti-DNA plaques. This problem was solved by using agarose instead of agar. Since the occurrence of small plaques may make reading of the test difficult, it was established that plaque size could be increased by decreasing the antigen density on the target cells. Free DNA in the gel inhibited plaque formation, indicating the specificity of the assay. Spleen cells from mice of the strains MRL/MP and NZB/W which are known to develop a stage of autoimmunity, produced plaques in numbers which were correlated to the age of the mice and to the anti-DNA antibody level in serum.

Animals↗
PubMed1987

Conjugation of DNA to erythrocytes.

DNA was conjugated to sheep red blood cells (SRBC) by chemical methods using CrCl3, poly-L-lysine or methylated bovine serum albumin as conjugation agents and by a physical method where conjugation was accomplished by incubation at 45 degrees C. The degree of conjugation was estimated using 32P-DNA (mean size 1 kbase pairs). Employing the CrCl3 method 5.8 +/- 3.6 micrograms DNA were conjugated per 10(8) SRBC at a concentration of 70 micrograms DNA/10(8) cells. At the same DNA concentration in the incubation medium 3.0 +/- 0.6 microgram DNA/10(8) cells were conjugated by poly-L-lysine, 4.1 +/- 0.8 microgram DNA/10(8) cells by methylated bovine serum albumin and approximately 4 micrograms DNA/10(8) cells when the cells were incubated at 45 degrees C. Cells conjugated with DNA by CrCl3 showed linearly increasing conjugation with increasing concentration of DNA. Cells conjugated by poly-L-lysine (pLL) or methylated bovine serum albumin seemed to be saturated by DNA at 30 micrograms DNA per 10(8) cells. At 45 degrees C the spontaneous adhesion of DNA to SRBC increased in the concentration range investigated. The degree of conjugation of DNA to SRBC was influenced by pH, and Ca2+.pLL-conjugated DNA-SRBC, but none of the other preparations were lysed in a hemolytic assay using anti-DNA antiserum from a patient with systemic lupus erythematosus.

Animals↗
PubMed1987

Transport of the alpha-amino-mono-carboxylic acid L-alanine by the beta-alanine carrier of the rabbit ileum.

The proposal that the beta-alanine carrier of the rabbit ileum is a high affinity carrier of the neutral amino acids was examined by means of measurements of influx across the brush border membrane of the intact epithelium using L-alanine as a representative of the neutral amino acids. Confirming the proposal, evidence was provided for mutual competitive inhibition between beta-alanine and L-alanine; and it was also demonstrated that a process contributes to the influx of L-alanine, which is characterized by a maximum rate of transport equal to that of beta-alanine and a Kt, which is equal to the Ki of L-alanine against the influx of beta-alanine. In the concentration range 0.01 to 0.125 mM the influx of L-alanine was found to be linearly related to the concentration indicating a significant unstirred layer influence on present and previous estimates of the Kt values for influx of amino acids across the brush-border membrane of intact intestinal epithelia.

Alanine↗
PubMed1987

Selective modulation of the CD4 molecular complex by Pseudomonas aeruginosa alkaline protease and elastase.

The binding of monoclonal antibodies against CD4 was specifically inhibited by treatment of human CD4+ cells with either alkaline protease (AP) or elastase (Ela), purified from Pseudomonas aeruginosa. Binding of antibodies against CD3 (pan T), CD5 (pan T), CD8 (T suppressor/cytotoxic), HLA-ABC, HLA-DR, HLA-DQ, HLA-DP/DR, and beta 2 microglobulin was not inhibited by AP or Ela. Heat-inactivation of the proteases at 65 degrees C for 20 min or treatment with the metal chelator EDTA abolished the inhibitory activity of both proteases. These findings may serve to develop novel immunological methods for the isolation and study of the lymphocyte CD4 structure, which plays an important part in the immune response.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1987

Influence of projection angles upon position of cementoenamel junction on radiographs.

The CEJ on radiographs is often used as a reference point in the assessment of alveolar bone loss. The aim of the present study was to test the stability of the radiographic CEJ ("RCEJ") in relation to the alveolar crest under varying angulations of the central X-ray beam. In an experimental model four types of extracted teeth were radiographed at 0 degree and 20 degrees vertical angulation and at 15 horizontal angulations varying from a 17.5 degrees mesial view to a 17.5 degrees distal view. The buccal alveolar bone margin was simulated by a steel needle. RCEJ-"crest" distances were read at a X 10 magnification. Changing the vertical angulation from 0 degree to 20 degrees reduced the RCEJ-"crest" distances for all tooth types (range of average reduction 2.2-4.1 mm). Horizontal angulations without concomitant vertical angulation had a significant effect but were without clinical significance. Horizontal angulations in combination with a 20 degrees vertical angulation had a considerable influence; in a mesial view, mesial RCEJ-"crest" distances decreased and distal ones increased, and vice versa in a distal view. The deviations from the true CEJ-crest distance demonstrated may be of clinical significance, and a critical attitude to alveolar bone loss measures on radiographs using the RCEJ as reference point is recommended.

Alveolar Process↗
PubMed1987

Erythrocyte CR1 (C3b/C4b receptor) levels and disease activity in patients with SLE.

Fifty-four patients with systemic lupus erythematosus (SLE) were examined for (1) CR1 (C3b/C4b receptor) levels on erythrocytes by an enzyme-linked immunosorbent assay, (2) levels of circulating immune complexes (IC) by a polyethylene glycol precipitation complement consumption method, and (3) concentrations of C3d split products in plasma by intermediate gel rocket immunoelectrophoresis. A preponderance of low CR1 levels was found among patients with SLE (mean 40%, range 13-106) as compared with normal controls (mean 70%, range 24-130) (p less than 0.001). The concentrations of circulating IC were elevated in 38% of 58 samples. The concentrations of C3d were elevated in 72%, and were positively correlated with the levels of IC (tau = 0.28; p less than 0.005) and with disease activity as assessed by a modification of the UCH/Middlesex criteria. Negative correlations were seen between the CR1 numbers and disease activity (p = 0.01), concentrations of circulating IC (tau = -0.14; p less than 0.005), and C3d (tau = -0.21; p less than 0.005). The changes found in CR1 levels on repeated study were, however, relatively small (less than or equal to 27%; median 5), even during periods of changing disease activity.

Adult↗
PubMed1987

Depressed natural killer cell activity in acute myocardial infarction.

Natural killer (NK) cell activity against K562 target cells was measured in patients within 24 h of acute myocardial infarction (AMI) and regularly thereafter for 6 weeks. NK cell activity was suppressed on days 1, 3, and 7 (P less than 0.01), day 14 (P less than 0.05) and at 6 weeks (P = 0.05) when compared to controls. Interferon, interleukin 2 and indomethacin enhanced NK cell activity on all days measured, but did not completely restore the defective NK cell activity. Serum from the patients did not suppress the NK cell activity of healthy mononuclear cells. The number of NK cells, identified as large granular lymphocytes (LGL), measured on days 1, 3, and 14 and at 6 weeks was not reduced in comparison to that of controls. Thus, the defective NK cell activity can be characterized as functional.

Adult↗
PubMed1986

Bradycardia after high-dose intravenous methylprednisolone therapy.

In 5 consecutive patients with rheumatoid arthritis who received intravenous high-dose methylprednisolone (MP) therapy (1 g daily for 2 or 3 consecutive days), a decline in pulse rate was observed, most pronounced on day 4. In one of the 5 patients the bradycardia was associated with complaints of substernal pressure. Reversal to normal heart rate was found on day 7. Electrocardiographic registrations showed sinus bradycardia in all cases. No significant changes in plasma concentrations of electrolytes were found. Careful observation of patients receiving high-dose MP is recommended. High-dose MP may be contraindicated in patients with known heart disease.

Adult↗
PubMed1986

Impaired indomethacin-boosting of the defective natural killer cell activity in patients with primary Sjögren's syndrome.

As it has been shown that the natural killer (NK) cell activity is depressed and the prostaglandin (PG) metabolism is disturbed in patients with primary Sjögren's syndrome (primary SS), we examined the in vitro effect of indomethacin on the NK cell activity. The NK cell activity against K 562 target cells was measured in 20 female patients with primary SS and in 18 female normal controls matched for age. Blood mononuclear cells were incubated with indomethacin (1 microgram/ml). Median baseline NK cell activity in primary SS was 15.4% (range 5.8-50.4) versus 24.7% (range 6.2-47.4) in the controls (p less than 0.05). After in vitro exposure to indomethacin median NK cell activity in the patients was 21.2% versus 34.9% in the controls (p less than 0.02). Indomethacin-enhanced NK cell activity was significantly higher than baseline NK cell activity in both patients (p less than 0.05) and controls (p less than 0.01), but the NK cell activity of the patients was significantly less enhanced than that of the controls (p less than 0.02). We conclude that the impaired indomethacin-boosting of NK cell activity in patients with primary SS probably reflects a decreased capacity of blood mononuclear cells to produce PG in vitro.

Humans↗
PubMed1986

Editorial comments to the four sets of criteria for Sjögren's syndrome.

The four most frequently used criteria for definition of Sjögren's syndrome--the Copenhagen, the Japanese, the Greek and the Californian criteria--are critically evaluated. The article focuses on the similarities and the dissimilarities as well as the advantages and the disadvantages between the various sets of criteria.

Humans↗
PubMed1986

Interleukin 2 augmentation of the defective natural killer cell activity in patients with primary Sjögren's syndrome.

Natural Killer (NK) cell activity against K562 target cells was measured in 21 female patients with primary Sjögren's syndrome (primary SS) and in 20 female normal controls matched for age. The in vitro effect of alpha-interferon (IF) and interleukin 2 (IL-2) on NK cell activity was examined and the percentage of large granular lymphocytes (LGL) in blood was measured. Median baseline NK cell activity in primary SS was 15.4% versus 24.4% in the controls (P less than 0.05). Median IF-enhanced NK cell activity in the SS group was 35.5% versus 49.6% in the controls (P less than 0.02). IL-2-enhanced NK cell activity was 35.5% versus 37.6% in the controls (n.s.) The proportion of LGL did not differ in the two groups. Median LGL/lymphocytes was 4.0% in the primary SS patients versus 4.5% in the controls (n.s.). We conclude that the defective NK cell activity in patients with primary SS is functional, as the number of LGL is normal. Further the NK cell activity off SS was restored by IL-2.

Adult↗
PubMed1985

Sézary syndrome: phenotypic and functional characterization of the neoplastic cells.

Phenotypic properties of the neoplastic cells in skin, blood and lymph node specimens from 5 patients with the Sézary syndrome were examined by immuno-enzymatic and -fluorescence labelling of cells and tissue sections with a monoclonal antibody panel. In 3 cases, the in vitro functional properties of the neoplastic cells (isolated from blood specimens) were also analysed using a reverse plaque-forming cell assay. 3 different immunological categories were identified as follows: T-helper/inducer neoplasms (3 patients); T-suppressor/cytotoxic neoplasms (1 patient); and neoplastic T-cells demonstrating characteristics consistent with a concept of their derivation from inducible suppressor T-cells (1 patient). These data provide conclusive evidence that Sézary syndrome is heterogeneous with respect to the immunological characteristics of the neoplastic cells.

Aged↗