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.

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.

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.

[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.

[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.

[Cellular aspects of the aging of articular cartilage. I. Condylar cartilage with a normal surface sampled from normal knees]

The authors studied the cellular density of articular cartilage taken from the femoral condyles of 77 autopsy subjects at Hôpital Lariboisière in Paris. This study showed a decrease in the cellular density (number of chondrocytes per mm2) going from the superficial zone towards the calcified zone of the cartilage in all layers, as a function of the age of the subjects. The decrease in cellular density is in the order of about 50% of the total chondrocyte number when subjects younger than 40 are compared with those older than 80. The demonstration of a regular increase in the number of empty lacunae per mm2 with the age of the subjects, i.e. lacunae without chondrocytes, suggest that the cause of this decrease in cellular density of the cartilage with age could be a physiological necrosis due to "exhaustion" of the chondrocytes. The metabolic activity of the chondrocytes may also decrease with age, as suggested by the increasing proportion of alcianophobic cells, cells which are weakly or not at all labeled by radioactive sulfates which indicate the sites of biosynthesis of proteoglycans. These cellular modifications could play a role of senile fibrillation of articular cartilage and in arthrosis.

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.

[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.

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.

[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.

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).

[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.

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.

[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.

[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.

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.

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.

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.

[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).

[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.