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Biomedical subjects

A Ryckewaert

Publications and source records attributed to A Ryckewaert.

At least 55 records · Page 3Linked to original sources
PubMed1984

[IgG-type antihistone antibodies. Diagnostic value in rheumatoid polyarthritis, scleroderma, spontaneous and drug-induced lupus].

IgG anti-histone antibodies were detected by indirect immunofluorescence in 6 out of 70 sera from rheumatoid arthritis with antinuclear factors, in 1 out of 13 from scleroderma, in 14 out of 25 from spontaneous systemic lupus erythematosus (SLE) and in 11 out of 14 from drug induced lupus. Rheumatoid arthritis patients with IgG anti-histone antibodies were characterized by the severity of joint involvement and by the high frequency of extraarticular features of the disease. SLE patients with anti-histone antibodies only differed from patients without such antibodies by a higher frequency of Raynaud phenomenon (p less than 0.05). Longitudinal studies of spontaneous SLE showed that IgG anti-histone antibodies correlated with disease activity (p less than 0.001). A significant correlation was demonstrated between anti-histone IgGs and anti-ds-DNA antibodies assessed by the Farr binding assay (p less than 0.0001). IgG anti-histone antibodies were rarely found in sera from patients with drug induced antinuclear antibodies without symptoms of SLE (1 out of 6 sera). In drug induced lupus, IgG anti-histone antibodies were found in the absence of high titers of anti-ds-DNA antibodies, and this discrepancy appeared to suggest the diagnosis of drug induced lupus. Finally, anti-histone antibodies were present in 5 out of 7 sera from acebutolol induced lupus.

Aged↗
PubMed1984

HLA-DR genotype risks in seropositive rheumatoid arthritis.

We studied the distribution of HLA-A, B, C, and -DR antigens in 77 Caucasian patients with sero-positive rheumatoid arthritis. Forty-four patients were genotyped and compared with the control panel of 110 unrelated Caucasian genotyped donors. The data obtained confirm the association of DR4 with RA, and reveal an increased risk of disease for patients carrying DR1, DR2, and DR3, compared to the risk for those carrying other antigens, such as DR5, DRw6, and DR7. There is a higher risk for DR4/4 homozygotes than for DR4/1, DR4/2, or DR4/3 heterozygotes. DR4/5, DR4/6, and DR4/7 have a lower risk than the previously mentioned genotypes. The genotype risks are compatible with the inheritance of a single, linked genetic determinant of disease susceptibility, but we are unable to distinguish between recessive and dominant inheritance of susceptibility using the "antigen-frequencies-amongst-diseases" method. DR4 seems to be more frequent in patients in whom onset occurs before the age of 35 (79% vs. 54% DR4 positive). A significant excess of DR3 + is observed in patients with toxic complications following treatment with gold salts (X2(1) = 8.96).

Adult↗
PubMed1984

Tumoral calcinosis: light and electron microscopic study with electron diffraction and x-ray microanalysis of the mineral deposit.

Samples of deposits taken from sites close to articulations in a young black African suffering from tumoral calcinosis with hyperphosphoraemia were studied by light and electron microscopy techniques. Light microscopy demonstrated lesions of a foreign body granuloma type in contact with calcium salt deposits suggesting that the process was of an active nature. Electron microscopy, and the demonstration of acid phosphatase activity, led to the identification of two cell types: mono or multinuclear macrophage type cells which phagocytose the deposit, and fibroblastic type cells. No signs of damage to the microvessels or the interstitial collagen were noted which could serve as a basis or a physiopathological explanation of the deposition. The deposits were analysed by energy dispersive X-ray microanalysis and by electron diffraction and were considered to be hydroxyapatite.

Acid Phosphatase↗
PubMed1984

[Cellular aspects of the aging of the articular cartilage. II. Condylar cartilage with fissured surface taken from normal and arthritic knees].

The authors studied the cellular density (number of cells per mm2) of cartilage taken from the femoral condyles of 46 cadavers (73 knees). In each case, the cartilage was taken from the summit of the condyle and, in 46 joints (27 subjects), a sample was also taken from the posterior surface (non weight-bearing zones). The fragments of non-calcified cartilage were sectioned with a cryostat and the sections (10 micrometers) were stained with hematein-eosin and solid red-Alcian blue. This study demonstrates: 1) a decrease in the cellular density of fissured cartilage compared to normal cartilage; this decrease appears to be proportional to the degree of fibrillation; 2) a decrease in the cellular density of apparently normal cartilage from arthrotic joints compared with normal cartilage from healthy joints; 3) with the age of the subjects, an increase in the density of the clones (number of clones per mm2) and the density of clonal cells (number of clonal cells per mm2) together with a decrease in the mean number of chondrocytes per clone. In fissured cartilage, the density of the clones, the density of the clonal cells and the number of chondrocytes per clone are slightly higher on the posterior surface of the condyles than on the summit of the condyles. These results emphasise the importance of the role that might be played by cellular phenomena in the mechanisms of deterioration of cartilage with aging and with arthrosis.

Adult↗
PubMed1984

[Phosphorus metabolism in a case of tumoral calcinosis].

Hyperphosphataemia with levels of 65 mg/l was found in a black African aged 20 with a 10-year history of tumour calcinosis. Levels of blood calcium, plasma ionised calcium, serum alkaline phosphatase, 24-hour urinary calcium and phosphate were all normal, as was renal function. Tubular phosphate reabsorption (TmP) was greater than 90 mg per litre of glomerular filtrate (N = 22-42). Levels of circulating parathyroid hormone, nephrogenic cAMP and serum vitamin D metabolites [25 OH D3, 24,25 (OH)2 D3 and 1,25 (OH)2 D3] were normal. The TmP fell by 36% on exogenous PTH stimulation (N = 30.25 +/- 6.7), and by 7.9% 120 min. after injection of acetazolamide. Our results confirm the conclusions of recent studies: patients with tumour calcinosis have disordered renal phosphate excretion with normal PTH secretion, normal PTH action on the renal tubule and normal vitamin D metabolism. In fact in these hyperphosphataemic patients, circulating 1,25 (OH)2 D3 levels would be expected to be low, whereas they were normal in our patient. An attempt at treatment with acetazolamide and phosphate chelating agents gave no significant results.

Acetazolamide↗
PubMed1984

A study of microvasculature in normal and inflammatory synovial membranes in the rabbit using light and electron microscopy and freeze fracture.

The Authors made a study of microvasculature in normal and inflammatory synovial membranes in the rabbit, by light and electron microscopy and with the use of freeze fracture. The synovial membrane of the knee was studied in 15 normal rabbits and in 22 rabbits in whom immunization with mycobacterium tuberculosis crude cytoplasmic water soluble extract had provoked inflammatory synovitis. A comparison between normal and inflammatory synovia by light microscopy showed, in inflammatory synovitis, a significant increase in the number of congested and obliterated microvessels (p less than 0.001) and in the number of endothelial nuclei per microvessel (p less than 0.0001). By electron microscopy no specific alteration of synovial microvessels was observed. A significant increase was found in the number of venules in inflammatory synovitis (p less than 0.01). The number of simple interendothelial tight junctions, defined by 1 or 2 interendothelial contacts, and of complex interendothelial tight junctions, defined by 3 or more interendothelial contacts, was similar in venules and in capillaries of inflammatory synovitis and of normal controls. The mean number and mean spacing of junctional strands in interendothelial tight junctions was similar in the microvessels of inflammatory synovitis and of normal controls. The Authors conclude that inflammation does not provoke specific alterations in synovial microvasculature but could induce an adaptative state resulting in increased synovial permeability.

Animals↗
PubMed1984

[Changes in vascular endothelial cells induced by serum from scleroderma and other connective tissue diseases].

The growth inhibition of in vitro vascular endothelial cell cultures by sera from patients with connective tissue disease was studied. Seven out of 30 sera from patients with progressive systemic sclerosis (PSS) exhibited a cytotoxic effect. The cytotoxic serum factor(s) was not specific to patients with symptoms (11 out of 27 sera from patients with a mixed connective tissue disease, MCTD; 5 out of 34 sera from patients with a systemic lupus erythematosus, SLE). The cytotoxic effect was not specific for vascular endothelial cells, it was also found on fibroblast cells cultures. Inhibitor(s) of cell growth in vitro was independent of antinuclear and anticytoplasmic antibodies and appeared as a common feature of all connective tissue disease with vascular symptoms.

Cells, Cultured↗
PubMed1983

Cell density of adult human femoral condylar articular cartilage. Joints with normal and fibrillated surfaces.

Cell and clonal density, lacunar and clonal diameters, and mean number of cells per single clone were studied in human femoral condylar cartilage of normal and osteoarthrotic joints. The values were related to the age of the subjects, the sampling site within the joints, and the depth from the articular surface. Cell density in every zone of both normal and diseased tissue decreased with increasing distance from the surface and increasing age. Cell density was significantly lower in age-matched osteoarthritic articular cartilage with an intact surface than in that of normal joints. The age-related decrease in the cell density accompanied an increase in the density of empty lacunae. The density of Alcian blue-stained cells, which actively synthesize proteoglycans as demonstrated by histoautoradiography, diminished with advancing age in all zones of articular cartilage. The percentage of these cells consistently decreased in the superficial and increased in the deep layers of the tissue in both normal and osteoarthritic joints. The clonal density was higher in the nonweight-bearing than in weight-bearing areas, and it increased with age, whereas the mean clone diameter and clonal cell number decreased.

Adult↗
PubMed1983

[Significance of anti-centromere antibodies. Clinical value].

The authors report 38 cases of patients with antinuclear antibodies directed against the centromere of the chromosomes. These were 32 cases of scleroderma, 2 cases of Raynaud's syndrome, 2 cases of rheumatoid arthritis, 1 case of polymyositis and 1 case of disseminated lupus erythematosus. In the cases of scleroderma, anti-centromere antibodies were detected in 54 p. cent of cases of Crest syndrome, for which they are a good laboratory marker; they were found more rarely in case of sclerodactyly (26 p. cent of cases) and acrosclerosis (14 p. cent of cases) and not at all in cases of localized scleroderma, diffuse scleroderma or eosinophilic fasciitis. Anti-centromere antibodies may be the only antinuclear antibodies in these patients. They can be detected using rapidly dividing cell cultures.

Adult↗
PubMed1983

[Significance of reduced complement level in the articular fluid. 81 cases].

Based on their own experience, the authors report that a fall in the complement level of joint fluid, which is particularly common in rhumatoid arthritis, is also seen in cases of systemic lupus eryrthematosis and a variety of arthritis: infectious arthritis, gout, articular chondrocalcinosis and psoriatic rheumatism. This should be taken into account when evaluating the diagnostic value of this test in rheumatoid arthritis.

Arthritis, Infectious↗
PubMed1983

[Anti-collagen antibodies. Their detection in rheumatoid polyarthritis, chronic atrophic polychondritis and various chronic inflammatory rheumatism].

The authors administered by passive haemagglutination, natural or denatured type I and II anticollagen antibodies in the serum of 83 rheumatoid polyarthritis, 20 ankylosing spondylarthritis, 30 relapsing polychondritis, 13 diffuse sclerodermics, 12 Gougerot-Sjögren syndrome patients. Type II natural anti-collagen antibodies are common in relapsing polychondritis (37 percent). They are rarer in rheumatoid polyarthritis (15 percent) and the frequency is identical to that found in patients suffering from gonarthrosis and coxarthrosis. Natural type II anti-collagen antibodies may be occur in etiopathogenesis of relapsing polychondritis. Denatured II ant-collagen antibodies are common during ankylosing spondylarthritis (35 percent) and diffuse sclerodermia, and are found in rheumatoid polyarthritis (23 percent) and in Gougerot Sjögren syndrome (25 percent). They possibly play a pathological role in these diseases although this has not been proved. They are detected almost as often in the synovial fluid of inflammatory rheumatisms (53 percent) and in gonarthrosis (41 percent).

Adult↗
PubMed1983

Evidence for defective osteoblastic function. A role for alcohol and tobacco consumption in osteoporosis in middle-aged men.

In a group of 11 men ranging in age from 35 to 50 years with idiopathic osteoporosis, most were mild alcoholics and heavy smokers. Two had absorptive hypercalciuria. Histomorphometry showed that the patients had low trabecular bone volume and mean trabecular thickness when compared with age-matched control subjects. Mean wall thickness was also markedly reduced in patients as compared with control subjects. The quantity of resorbed bone was extrapolated from the calculated mean interstitial bone thickness. Resorption was not significantly different in patients and control subjects. Consequently, in this group of patients with severe osteoporosis, the pathogenesis was characterized by markedly decreased bone formation.

Adult↗
PubMed1983

[Bone and phosphoro-calcium metabolism in reflex sympathetic dystrophy].

A combined study organised by the French Society of Rheumatology was devoted to the investigation of bone and phosphoro-calcium metabolism in cases of reflex sympathetic dystrophy. The following observations were made: the usual phosphoro-calcium parameters are not altered, apart from a slight elevation of the urinary calcium in multifocal forms of the disease, during the 3rd and 4th months; the level of PTH, studied in 11 patients, was normal in each case; the examination of 8 bone biopsies, one performed in the 7th week and six others performed during the 3rd and 4th months of the disease, showed, initially, invasion of the spongy tissue by oedema, signs of marrow stress and bone stress, with a reduction in the number of osteoblasts, without any marked alteration of bone remodelling. At a later stage, the biopsy shows intense bone remodelling with hyperosteoclastosis and hyperosteoblastosis and the formation of irregular bone tissue which later becomes lamellar. Electron microscopic study of two biopsies revealed signs of acellular demineralisation with normal appearance of the osteoblasts and osteoclasts.

Bone and Bones↗
PubMed1983

[Hemopigmented villonodular synovitis: ultrastructural study and a comparison with hemophiliac synovitis].

In a study of the ultrastructure of two cases of villonodular synovitis and two cases of haemophiliac synovitis, the authors observed very similar lesions. In both diseases, the lesions of the superficial layer of the synovium consisted of intermediate type (type C) synoviocytes loaded with iron pigments or lipid vacuoles. In the deep layer, the authors observed numerous macrophages loaded with siderosomes, lipid inclusions or phagocytosed red blood cells, giant cells and capillaries with a thickened basement membrane with a layered appearance. The cytoplasmic membranes of the synoviocytes were joined by desmosomes or filopodal digitations. The similarity of the lesions in the two diseases suggests a common histogenetic mechanism for the synovial lesions: chronic haemarthrosis.

Cytoplasm↗
PubMed1982

[Response of the joint tissues to the presence of a foreign body implanted into the rabbit knee. A new model of experimental arthrosis].

The joint tissues (synovium, articular cartilage and bone), respond rapidly and consistently to the presence of a piece of polypropylene surgically implanted into the Rabbit knee joint. In the contact of a foreign body, a synovium proliferates in an attempt to isolate and exclude the intruder from the joint cavity. The articular cartilage degenerates at the sites of maximal pressure. Its superficial layer undergoes cell necrosis and fibrillation and is progressively destroyed in the process of mechanical grinding. At the sites of lower pressure, the chondrocytes proliferate and form the metabolically hyperactive clones which have increased capacity to incorporate tritiated thymidine and radioactive sulfate. The glycosaminoglycan content of articular cartilage, compared to the shamoperated control side, rapidly decreases after operation as suggested by a loss of metachromatic staining and lower per unit weight concentration of uronic acid and hexosamine. In addition to the above changes, the osteophytes quickly develop at the articular margins from the proliferating synovial tissue while underlying bone become thicker and eburnated. These foreign body induced changes in articular morphology and metabolism resemble closely those observed in osteoarthrosis. The present model therefore may prove useful in studying the latter condition.

Animals↗
PubMed1982

[Streptococcal rheumatic fever in adults].

Thirty-seven cases of streptococcal rheumatic fever in adults (20 women and 17 men; mean age 33 years) are reported. Only 3 patients had a history of previous rheumatic fever. In 73% of the cases untreated sore throat had occurred 8 to 30 days before the condition developed. Throat swabs taken during the rheumatic attack were positive for Streptococcus haemolyticus in only 5 out of 22 patients. The joints most commonly affected were those of the lower limbs and the symptoms were severe; in 2 out of 3 patients other joints were subsequently involved. Five patients had stable mitral regurgitation of undetermined duration, with systolic murmur. ECG abnormalities were noted in 7 patients, including 5 with prolongation of the PR interval and 2 with moderate elevation of the ST segment; these abnormalities regressed in all cases. No specific skin lesions were observed. The streptococcal infection was associated with a rise in antistreptolysins in 73% of the cases, a rise in antistreptokinases in 80% and a rise in both types of antibodies in 97%. Response to antibiotics and anti-inflammatory drugs was satisfactory in all cases. Cure was achieved within less than one month in 57% of the patients, but the condition lasted three years in 3 patients.

Adolescent↗