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Biomedical subjects

A Ryckewaert

Publications and source records attributed to A Ryckewaert.

At least 37 records · Page 2Linked to original sources
PubMed1986

[HLA system and complications of the treatment of rheumatoid polyarthritis with D-penicillamine].

The data of the literature concerning the relationship between complications of D-penicillamine treatment and the HLA system are discussed. This relationship particularly concerns the renal complications which are associated with HLA antigens B8 and DR3, although this relation is not sufficiently strong to be used in practice in the indications for treatment with D-penicillamine.

Arthritis, Rheumatoid↗
PubMed1985

Amyloid deposits in human knee and hip joints.

A systematic search for articular amyloidosis was carried out on both knees of 53 autopsy cases and on 26 femoral heads resected during surgery for hip prosthesis. Typical amyloid deposits exhibiting green apple birefringence following Congo red staining and thioflavin T fluorescence were found in 58.5% and 29% of the cases, in the knee and hip joint respectively. They occurred more frequently in articular cartilage than in the synovium, and in elderly subjects more than young ones. In the knee joint, the osteoarthritic changes and to a minor extent synovial inflammation appear to be positively correlated for the presence of intraarticular amyloid deposits. Such a correlation was not observed for the presence of calcium pyrophosphate dihydrate crystal deposits.

Aged↗
PubMed1985

Osteoclast abnormalities in idiopathic osteopetrosis. Reference to the ultrastructural histochemistry study.

In order to investigate skeletal abnormalities in a case of idiopathic osteopetrosis, a bone biopsy was taken from the anterior iliac crest and prepared for ultrastructural and histochemical study. There was a drastic reduction in osteoclastic bone resorption. The ruffle border and sealing zone, which are the osteoclast cell surface markers of bone resorption, were absent. The cells were highly vacuolated, and the vacuoles contained large amounts of a residual organic material which reacted strongly with acid phosphatase. Acid phosphatase activity was never found outside the cell, and in particular, not at the bone-cell interface. This suggests that the defect in bone resorption is caused by cell membrane abnormalities and the lack of ruffle border formation, rather than the inability of the lysosomal enzymes to digest the bone matrix.

Acid Phosphatase↗
PubMed1985

HLA antigens and seronegative rheumatoid arthritis.

HLA antigens and clinical features in a series of 46 Caucasian patients (40 females, 6 males) and definite repeatedly seronegative rheumatoid arthritis (RA) of more than two years' duration (mean 11.6 years) were compared with those in 77 seropositive RA patients and 110 controls of the same ethnic and geographic origin. Seronegative RA appeared to be less often erosive than seropositive RA, and seronegative patients had fewer extra-articular features. The frequency of the HLA antigen DR1 was raised in seronegative patients as compared with controls (p = 0.006, relative risk = 3) and with seropositive patients (p less than 0.05). HLA-DR4 was slightly increased in seronegative patients compared with controls (p less than 0.05) but was clearly less so than in seropositive patients (p less than 0.005). Early onset of disease was very significantly associated with HLA-DR1 in seronegative patients (p = 0.007), whereas HLA-DR4 was present more frequently in seropositive patients with onset prior to age 35 (p less than 0.05). No correlation between HLA antigens and intolerance to drugs was found in seronegative patients, whereas in seropositive patients side effects to gold salts were associated with DR3. These results suggest that seropositive and seronegative RA have distinct HLA-DR associations, especially in disease of early onset, in addition to well established clinical differences.

Adolescent↗
PubMed1985

[Antiphospholipid antibodies, thrombosis and lupus disease. Value of the assay of anticardiolipin antibodies by the ELISA technic].

The authors have developed a sensitive immunoenzymatic method for assaying anti-cardiolipin antibodies in the serum of patients with lupus (SLE). These antibodies were present in the serum of 43/108 SLE patients, particularly in those patients with either false syphilis serology (p less than 0.02) or circulating anticoagulant (p less than 0.05). The mean titre of anti-cardiolipin antibodies was higher in the group with positive VDRL (less than 0.03). The anti-cardiolipin antibody titre was independent of the anti-native DNA antibody titre, but there was a correlation with the anti-denatured DNA antibody titre (p less than 0.02). This correlation can be partially explained by the antigenic similarity (phosphodiester bridge) between the two molecules. The preliminary clinical studies have not shown any correlation between the presence of anti-cardiolipin antibodies and the presence of signs such as thrombocytopenia, haemolysis, cerebral vascular accident, venous thrombosis, recurrent abortion. A longitudinal study of certain patients suggests that the anti-cardiolipin antibodies may disappear at the time of thrombotic accidents, which induces fixation of these antibodies to a platelet or vascular target and as a result of corticosteroid therapy.

Antibodies, Antinuclear↗
PubMed1985

[Vertebral compression with intrasomatic vacuum images. Apropos of 2 cases with histological control by trocar biopsy].

The significance of a gas shadow, known as an intra-somatic space, seen in cases of vertebral compression is discussed in relation to two cases with histological confirmation by means of trocar aspiration biopsy of the vertebra. The presence of this image is in favour of a neoplastic or infectious aetiology; however, in view of the limited experience, histological confirmation by aspiration biopsy of the vertebra is indicated in the presence of one or more reasons for suspecting a neoplastic aetiology. The most satisfactory pathophysiological hypothesis to explain the appearance of an intra-somatic space is that this image generally appears in cases of osteoporotic vertebral compression complicated by a certain degree of osseous ischaemia.

Aged↗
PubMed1984

[Determination of anti-native DNA antibodies by immunofluorescence on Crithidia luciliae. Correlation between renal involvement and the presence of high-avidity anti-native DNA antibodies in lupic disease].

Low avidity native DNA - anti-native DNA complexes dissociate at alkaline pH and in high molarity solutions. This property was used to modify the indirect immunofluorescence reaction on Crithidia luciliae in order to assay high avidity anti-native DNA antibodies resistant to alkaline and strongly saline solutions. Assays were performed in the sera of 36 patients (31 women and 5 men) with systemic lupus erythematosus (SLE). Seventeen of these patients had histologically significant lupus nephritis (WHO types III, IV and V) and 19 had no renal, urinary or biochemical abnormalities. The mean titer of total anti-native DNA antibodies was similar in both groups, but the titer of high avidity anti-native DNA antibodies was significantly higher in patients with lupus nephritis. The percentage of patients with high avidity antibodies was 87% in the group with renal involvement and 28% in the group with no kidneys involvement. Thus, lupus nephritis should be feared when anti-native DNA antibodies with high dissociation constant are found in the sera of SLE patients.

Animals↗
PubMed1984

Lipid peroxides in human articular cartilage.

The hypothesis that increased generation of lipid peroxides (LP) causes articular cartilage damage in older patients and in those with osteoarthritis was tested by directly measuring LP tissue levels in various layers of human articular cartilage. The LP content was significantly greater in the superficial than in the deeper portion of the cartilage, but lower in cartilage than in liver, kidney, adrenal glands and synovium. When LP were related to the total lipid content of these tissues, a high peroxide per lipid ratio was obtained for articular cartilage. The relevance of these findings to the mechanism of cartilage fibrillation is discussed.

Adrenal Glands↗
PubMed1984

Extended treatment of primary osteoporosis by sodium fluoride combined with 25 hydroxycholecalciferol.

Nineteen patients suffering from primary osteoporosis, all having at least one vertebral collapse, initially received 50 mg of sodium fluoride alone per day for 6-18 months. Subsequently fluoride was associated with 25-50 micrograms of 25 OH cholecalciferol (calcifediol) per day for 6-18 months in 12 of these patients and 9 were treated for 31-58 months. As control group, 9 patients were given placebo for 6-18 months. The effect of the treatment was assessed by three methods: 1) the metacarpal index (MI) determined by radiogrammetry, 2) the calcium content of the hand bone (Ca) measured by local neutron activation, 3) the iliac bone histomorphometry. MI and (Ca) did not change significantly at any time in any group. In each group there was a significant increase in trabecular bone volume, osteoid volume, osteoid surfaces and a significant decrease in mineralization fronts. On the other hand, the changes in osteoblastic surfaces, osteoclastic surfaces, number of osteoclasts/mm2 were not significant in any group. No change was observed in the placebo group. These data suggest that the increase in the trabecular volume of fluorided bone is mainly due to the increase in osteoid which itself is due to a bone mineralization defect despite the association of calcifediol. This is probably one of the reasons why (Ca) does not change significantly.

Aged↗
PubMed1984

[Determination of anti dsDNA antibodies by immunofluorescence using Crithidia luciliae. I--Diagnostic and prognostic value in systemic lupus erythematosus. Comparison with the Farr radioimmunoassay].

Antibodies to double stranded (ds) DNA were sought by the indirect immunofluorescence method using Crithidia luciliae in 196 sera from patients suffering from hepatic, thyroid or inflammatory rheumatic disorders. Anti ds DNA antibodies were demonstrated in 29 out of 45 systemic lupus erythematosus (SLE) sera. Lower titers were found in 3 out of 7 sera from drug-induced SLE, 2 out of 6 from mixed connective tissue diseases, 1 out of 60 from scleroderma, 2 from unclassified arthritis, 8 out of 40 from rheumatoid arthritis with antinuclear factors, and in 4 out of 15 sera from chronic hepatitis. For SLE diagnosis the sensitivity of the method was 73 percent, its specificity was 87 percent. 84 percent of these results were in agreement with those obtained with the Farr method, but titers did not correlate well. The sensitivity of the Farr method was 64.5 percent, its specificity was 85 percent. In this study, high titers of anti ds DNA antibodies demonstrated on Crithidia Luciliae did not correlate with disease severity. Low titers of anti14C labelled DNA antibodies demonstrated by the Farr assay correlated with inactive SLE without nephritis. The immunofluorescence assay using Crithidia luciliae is a valid method to detect anti ds DNA antibodies but does not allow prognostic conclusions in SLE.

Animals↗
PubMed1984

[Levels of anti-nDNA using immunofluorescence on Crithidia luciliae. II. Prognostic value of complement-fixing anti-nDNA. Longitudinal study of 16 lupus disorders].

Measurements of the hemolytic complement level and titrations of anti dS DNA antibodies by immunofluorescence using Crithidia luciliae and by the Farr binding assay were performed in 13 females and 3 males suffering from systemic lupus erythematosus (SLE). In each patient, 2 to 5 serum samples were analyzed during a mean follow up time of 16.6 months. The complement fixing ability of the anti dS DNA antibodies was also investigated. In this longitudinal study the titers of the dS DNA antibodies detected by immunofluorescence correlated with the Farr binding assay results. Mean anti dS DNA antibody titers were significantly higher and CH 50 levels were lower when SLE was active. Among sera with anti dS DNA antibodies, only sera with high titers (greater than or equal to 1/80), fixed complement. Study of individual cases disclosed that an increase in complement fixing anti dS DNA antibodies could occur in the absence of disease activity. Sera from patients with severe organ involvement, in particular with nephritis had low titers of anti dS DNA antibodies with no complement fixation activity. There was no relationship between falls in serum complement level and the complement fixation ability of anti dS DNA antibodies. Thus, complement fixation capacity of anti dS DNA antibodies correlates better with antibody titer than with SLE severity or activity.

Adult↗