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[Xeroradiography in rheumatology].

Xeroradiography is a new and simple radiodiagnostic technique that makes it possible to analyse on one positive film not only the bone tissue but also the neighbouring structures (ligaments, muscles, fatty tissue, the vessels, and the skin). On the basis of about 100 examinations, the authors indicate the value and the limitations of the technique in rheumatological practice. Because of the technical aspects of the technique, the dorsolumbar spine and the facial massif are poorly visualized. The swamping of the contrast also limits its use for cases of demineralization (osteoporosis). On the other hand, the information provided by the technique in cases of Paget's disease, articular or para-articular calcification, pathological conditions of the tendons (rupture, calcification), and bone tumours appears to be of great value. The early diagnosis of cases of inflammatory rheumatism and the surveillance of Silastic prostheses used in surgery on rheumatic hands are also facilitated.

Arthritis, Rheumatoid↗

Bone fragmentation in the rheumatoid wrist: radiographic and pathologic considerations.

A peculiar pattern of bone fragmentation of the wrist was noted in 16% of 50 rheumatoid patients. This involved erosion of the navicular, distal radius and ulna, carpal fusion, demineralization, and the presence of an elongated bony spicule overlying the radiocarpal joint. Additional examples were found in rheumatoid cadavers. Pathogenesis of the alteration was not entirely clear although contributing factors included extensive pannus proliferation, osseous compression and fracture. The fate of the detached spicules, their relationship to "fistulous rheumatism", and the differential diagnosis are discussed.

Aged↗

[Symptomatic rickets in adolescents].

Although systematic vitamin D supplementation in adolescents remains debated, rickets is nevertheless a well recognized pathology in this age group. Adolescence is an at-risk period because of rapid growth, insufficient calcium intake and/or vitamin D status. Surveys have shown that calcium intake is insufficient (< 1000 mg a day) in 45% of boys and 71% of girls and that vitamin D status is deficient (25-OH-D < 10 ng/ml). The aims of the study carried out by the Calcium Group of the Société Française de Pédiatrie, were to evaluate the frequency of rickets, and to define the criteria for the adolescent population at risk. Forty-one adolescents with rickets were hospitalized between 1985 and 2000. Most of the cases were from the Northern France: 20 from Paris and suburbs, eight from the North-West, four from the North, four from the North-East; five were from the Center of France. The mean age was 13 years and two months for the 28 girls, and 14 years and four months for the 13 boys. Eighty per cent of the adolescents were from immigrant families (33/41): 15 were from sub-Saharan Africa, ten from North Africa, six from Pakistan and two from Turkey. Two thirds of the adolescents were hospitalized in the 2nd quarter of the year. Some adolescents suffered from lower limb pain, 16 had deformations of lower limbs, particularly genu valgum, associated with pain; seven others had either muscle spasms (4), tetany (3). Serum calcium level was low (average 1.84 mmol/l: [1.1-2.5]), and serum 25-OH D level was extremely low. Radiographic characteristics observed were metaphyseal strips on the knees, with condensed edges at times, with the presence of bone demineralization. The treatment combined calcium and vitamin D, and was often administered intravenously when a hypocalcemia was detected. Rickets is not frequent in adolescents, but nonetheless this pathology is not exceptional, and the number of cases is probably under-estimated. Rickets affects immigrant adolescents in particular but nevertheless could also present a certain risk period for the general population.

Adolescent↗

[Capsular retraction of shoulder: prospective study of imaging benefits in 20 patients].

PURPOSE: To evaluate the contribution of principal imaging techniques in diagnosis and treatment in adhesive capsulitis of the shoulder. MATERIALS AND METHODS: In 20 patients presenting adhesive capsulitis of shoulder since mean of 6,7 months, the following examinations were performed: radiographies, angioscintigraphy, MRI as well as an opaque arthrography and a bursography associated with corticosteroid injection. Patients were followed during one year. RESULTS: The opaque arthrography was to affirm the adhesive capsulitis for the inclusion of the patients. Radiographies (patchy demineralization) and scintigraphy (hyperfixation) were often pathological. In MRI, T1 fat-saturated sequences after contrast injection almost always showed enhancement of the articular capsula, the synovia, the miscellaneous bone or the sub-acromial bursa. The latter was often modified and retracted at bursography. In 19 of 20 cases, a functional improvement was observed after the opacifications. CONCLUSION: Therapeutic effect of both arthrography and bursography is almost proved. Post contrast MRI confirms presence of vascular troubles in all the shoulder structures even at this advanced stage.

Adult↗

Standardless PIXE analysis of thick biomineral structures.

The particle-induced X-ray emission (PIXE) of thick biomineral targets provides pertinent surface analysis, but if good reference materials are missing then complementary approaches are required to handle the matrix effects. This is illustrated by our results from qualitative and semiquantitative analysis of biomaterials and calcified tissues in which PIXE usually detected up to 20 elements with Z > 14 per sample, many at trace levels. Relative concentrations allow the classification of dental composites according to the mean Z and by multivariate statistics. In femur bones from streptozotocin-induced diabetic rats, trace element changes showed high individual variability but correlated to each other, and multivariate statistics improved discrimination of abnormal pathology. Changes on the in vitro demineralization of dental enamel suggested that a dissolution of Ca compounds in the outermost layer results in the uncovering of deeper layers containing higher trace element levels. Thus, in spite of significant limitations, standardless PIXE analysis of thick biomineral samples together with proper additional procedures can provide relevant information in biomedical research.

Animals↗

Acid attack and cathepsin K in bone resorption around total hip replacement prosthesis.

Normal bone remodeling and pathological bone destruction have been considered to be osteoclast-driven. Osteoclasts are able to attach to bare bone surface and produce an acidic subcellular space. This leads to acid dissolution of hydroxyapatite, allowing cathepsin K to degrade the organic type I collagen-rich osteoid matrix under the acidic condition prevailing in Howship lacunae. Using a sting pH electrode, the interface membrane around a loosened total hip replacement prosthesis was found to be acidic. Confocal laser scanning disclosed irregular demineralization of the bone surface in contact with the acidic interface. Cathepsin K, an acidic collagenolytic enzyme, was found in interface tissue macrophages/giant cells and pseudosynovial fluid. Tissue extracts contained high levels of cathepsin K messenger RNA (mRNA) and protein. These observations suggest the presence of an acid- and cathepsin K-driven pathological mechanism of bone resorption, mediated not by osteoclasts in subosteoclastic space, but rather by the uncontrolled activity of macrophages in extracellular space.

Acids↗

Severe hyperparathyroidism associated with prolonged hungry bone syndrome in a renal transplant recipient.

Although widely believed to resolve within 6 to 12 months of successful renal transplantation, hyperparathyroidism may persist or develop after renal transplantation and eventually require parathyroidectomy. Avid calcium retention by demineralized bones (hungry bone syndrome) is well-recognized after parathyroidectomy and usually resolves after a few weeks. This report documents the case of a renal transplant recipient with persistent hyperparathyroidism who developed a pathological fracture of the pelvis and required parathyroidectomy 1 year after transplant and then manifested severe and prolonged hungry bone syndrome lasting for more than 20 months postoperatively. The clinical features and treatment of hyperparathyroidism in renal transplant recipients are discussed, as are diagnosis, pathogenesis, and management of hungry bone syndrome. Recognition of renal transplant recipients at greater risk for severe hungry bone syndrome should permit earlier and more aggressive management of this sometimes protracted complication of parathyroid surgery.

Adult↗

[Physiopathology of osteoporosis (author's transl)].

Osteoporosis is the result of the progressive loss of bone substance which occurs during a lifetime. Its histomorphological characteristics have been well-defined and it appears to be a single entity more particularly related to the general problem of cellular senescence. The rate at which bone is lost can be influenced by many events or general factors, known or unknown, which are capable of accelerating or slowing down its progression. The period when the fracture threshold is passed appears to depend on a bone mass which is weak at the end of the growth period, followed by genetic, mechanical--related more specifically to insufficient muscular activity--, hormonal-hypo-oestrogenemia-factors, and pathological episodes of more rapid demineralization (immobilization, corticotherapy) which become more irreversible with advancing age.

Adrenal Cortex Hormones↗

Neonatal primary hyperparathyroidism in familial hypocalciuric hypercalcemia.

A Japanese female neonate exhibiting severe respiratory distress was found to have primary hyperparathyroidism. Features included demineralization of the bones, hypercalcemia, hypophosphatemia, and elevated levels of parathyroid hormone, together with marked, generalized aminoaciduria. Four enlarged parathyroid glands were surgically removed, and remineralization of the bones was noticed after the operation. The characteristic pathologic change of the glands was chief cell hyperplasia. A survey of the family identified three other hypercalcemic but asymptomatic relatives. The mode of inheritance was autosomal dominant. This patient seems to be the second neonate with familial hypocalciuric hypercalcemia to be described in the literature.

Adult↗

Endogenous lipids in matrix-induced bone morphogenesis.

Demineralized matrix was delipidized with chloroform methanol before and after demineralization and implanted in muscle of allogeneic rats. Because lipids are difficult to separate completely from bone collagen, another preparation was gelatinized and delipidized with either chloroform methanol or acetone or both. Bone matrix demineralized without delipidization induced formation of a spherical-shaped deposit of new bone, which was remodeled to form a shell of cortical bone and central pool of normal hematopoietic bone marrow. When the bone was delipidized, only 20% to 25% was resorbed and replaced by new bone; unresorbed matrix failed to recalcify. Gelatinized bone matrix delipidized before implantation was even less well resorbed or replaced by new bone, but 12% to 44% of the matrix residue recalcified. The new deposits of bone were colonized by blood-borne bone marrow-derived stem cells and developed central pools of normal hematopoietic bone marrow. Recalcified residual matrix did not develop bone marrow. Additional investigations are required to determine whether the host bed adipocytes provide the phospholipids for recalcification of bone matrix. There was no preliminary recalcification in matrix-induced bone development, even though the 2 processes may occur simultaneously under specified experimental and pathologic conditions. Additional investigations are in progress to determine whether certain acetone soluble lipids may form the endogenous delivery system for bone morphogenetic protein and induced bone development.

Adipocytes↗

Management strategy for unicameral bone cyst.

The management of a unicameral bone cyst varies from percutaneous needle biopsy, aspiration, and local injection of steroid, autogenous bone marrow, or demineralized bone matrix to the more invasive surgical procedures of conventional curettage and grafting (with autogenous or allogenous bone) or subtotal resection with bone grafting. The best treatment for a unicameral bone cyst is yet to be identified. Better understanding of the pathology will change the concept of management. The aim of treatment is to prevent pathologic fracture, to promote cyst healing, and to avoid cyst recurrence and re-fracture. We retrospectively reviewed 17 cases of unicameral bone cysts (12 in the humerus, 3 in the femur, 2 in the fibula) managed by conservative observation, curettage and bone grafting with open reduction and internal fixation, or continuous decompression and drainage with a cannulated screw. We suggest percutaneous cannulated screw insertion to promote cyst healing and prevent pathologic fracture. We devised a protocol for the management of unicameral bone cysts.

Adolescent↗

Structure of the osteocyte capsule in rats with hypervitaminosis-D and rickets.

A histochemical and topo-optical study was made of the changes of the osteocyte capsule (OC) of the cortical and spongious bone layers of the tibia and vertebra of rats with hypervitaminosis-D and rickets. In hypervitaminosis-D the number of stained OCs was found to decrease. After treatment with high doses of vitamin D, a broadening of the OCs was noted in the area of demineralizing bone. Under the polarization microscope a decrease occurred in the proportion of birefringent OCs, more marked in birefringence than in staining. Since bone demineralization due to vitamin D was not followed by a rise in the number of osteoclasts, it is concluded that osteocytic activity has an important role in demineralization as shown by the broadened OC. In rachitic rats considerably fewer OC took the stain and showed birefringence than in the controls. Thus, alteration of the OC structure disturbs the nutrition of bone tissue and thereby aggravates the pathological process.

Animals↗