An ultrastructural study of articular chondrocalcinosis in cases of knee osteoarthritis

A study was made by transmission electron microscopy of tissue specimens (cartilage, meniscus and synovial membrane) taken from 5 knees presenting radiological and anatomical signs of articular chondrocalcinosis and osteoarthritis. It was part of a broader study which included analysis of the same specimens by macroscopy and light microscopy as well as by X-ray diffraction of the mineral deposits. In cartilage and meniscus juxta-cellular calcium pyrophosphate dihydrate (CPPD) crystals of variable sizes were observed in the extracellular organic matrix, independent of the collagen fibrils. They occurred mainly in the superficial and middle zones but could also be seen intermingled with the apatite crystals in the cartilage calcified zone. In synovial membrane most of the CPPD crystals were extracellular but some of them could be seen in cytoplasmic phagocytic vacuoles. These observations are in agreement with those in the literature regarding the ultrastructural picture of chondrocalcinosis and support the thesis that the crystals originate in the cartilage and are phagocytized in the synovial membrane. Although the results of the present study do not provide direct evidence of a relationship between chondrocalcinosis and osteoarthritis, the data of the ultrastructural investigation appear nevertheless of great interest as a complement to the data furnished by light microscopy.

Physical and chemical analyses of the mineral substance during the development of two experimental cutaneous calcifications in rats: topical calciphylaxis and topical calcergy

In subcutaneous calcinoses induced in rats by topical calciphylaxis and topical calcergy, the ultrastructural aspects related to the evolution of calcified deposits were previously described. In the present study by means of X-ray diffraction, infrared spectrometry and electron spin resonance, different biophysical analyses are performed on the mineral substance deposited during development of calciphylaxis and calcergy. A rapid evolution of the calcium phosphate deposits into hydroxyapatite was noticed along the first 20 days of the calcinoses; from then, there is no important modification even at the later stages, and the characteristics of the mineral substance are mostly similar to that of bone tissue. The concentration of trace elements such as Mg2+ and Fe2+, is found higher in cutaneous calcinoses than in bone tissue.

Biochemical findings in blood of aged patients with femoral neck fractures: a contribution to the detection of occult osteomalacia

A study was made in Geneva of 44 patients with femoral neck fractures and no risk factor of osteomalacia to determine concentrations of 25OHD3, calcium, phosphorus, alkaline phosphatase, albumin, and globulins in blood. The results were compared with those obtained for control groups of adult and aged subjects, as well as of 21 subjects operated on for hip osteoarthritis. For the detection of occult osteomalacia, femoral head bone tissue from 14 patients with fractures was examined by histomorphometric methods. In more than a third of the cases, 25OHD3 and serum albumin values were lower than those found for adult and even aged control subjects. Some slight histological signs of osteomalacia were observed in 1 patient with a femoral neck fracture, but there was no correlation between the histologic and the blood data. In practice, when dealing with aged people with no obvious risk of osteomalacia, it is important that a systematic antiosteomalacia treatment consisting of large supplements of vitamin D be avoided and that the conditions of diet and living be carefully controlled.

Olecranon bursitis related to calcium pyrophosphate dihydrate crystal deposition disease

A case of olecranon bursitis in an 81-year-old patient is presented. Analysis of the bursal fluid revealed positive birefringent crystals; radiographs showed calcifications in the distal triceps tendon. A bursectomy was performed. X-ray diffraction analyses demonstrated calcium pyrophosphate dihydrate patterns in a subcutaneous "tophus" and in a specimen of the tendon. On histologic examination, there was a bursitis with positive birefringent crystals on the bursa's inner surface; histologic images of "chondrocalcinosis" were observed in and around the tendon. It is concluded that bursitis may be part of the extraarticular manifestations of calcium pyrophosphate dihydrate crystal deposition disease.

Ultrastructural and cytochemical aspects of the initial phases of an experimental cutaneous calcinosis (calcergy) in the rat

In rats a subcutaneous injection of KMnO4 leads to the calcification of the connective tissue. During mineral deposition, both intra- and extracellular changes are observed in the connective tissue. The intracellular phase is characterized by the formation of intramitochondrial granules and cytoplasmic vesicles, both in fibroblastic and extrinsic cells. In the extracellular phase, numerous heterogeneous matrix vesicles appear in the extracellular matrix. At the same time, globular particles which are resistant to microincineration, are observed between the collagen fibrils. The mineralization of the extracellular matrix takes place in two stages. The first stage comprises the appearance of needle-like structures and round aggregates. The needle-like structures are observed occasionally in the matrix vesicles and often in the extracellular matrix where they appear isolated or diverging from a central point. The round aggregates, composed of dense particles, are seen in the ground substance between the collagen fibrils. The second stage is characterized by a progressive mineralization of the collagen fibrils and the elastic fibers, without formation of extended calcified plaques.

Carpal tunnel syndrome in chondrocalcinosis of the wrist. Clinical and histologic study

Carpal tunnel syndrome (CTS) defined electromyographically was found in 8 of 22 unselected patients with chondrocalcinosis of the wrists (bilateral in 6, unilateral in 2). Thenar atrophy was the most frequently encountered clinical sign. In the hands with CTS, calcifications of the wrist were more extensive than in the hands, without CTS. Degenerative joint changes of the hands were significantly more frequent in the group suffering from CTS. Surgery was performed in 5 patients with CTS. Microscopic examination of the volar carpal ligament and the flexor synovial tendon sheath failed to reveal histologic signs of chondrocalcinosis. However, the presence of scarce crystals, as seen in polarized light as well as electron microscopy, suggests a minor form of chondrocalcinosis.

Achilles tendinitis associated with chondrocalcinosis

Achilles tendinitis was observed in 3 patients with idiopathic articular chondrocalcinosis. It was associated with linear radiological calcifications which in this condition are not unusual but generally asymptomatic. Crystals presumed to be calcium pyrophosphate dihydrate (CPPD) were found in the 2 cases that were biopsied. In 2 patients the acute inflammation of the tendon subsided after several days, but in the 3rd it lasted 4 1/2 months, and resulted in a cicatricial thickening of the tendon with a progressive disappearence of the calcifications. Therefore, the development of Achilles tendinitis in an elderly patient may be an inflammatory reaction to CPPD crystal deposits.

The mineralization processes in teleost fish scales

In Teleost fish scales, growth and mineralization are continuous. Different mineralization processes can be distinguished. The external layer of the scale is the first to be mineralized and may be classified as the initial calcifying structure of the scale. The initial calcification loci are matrix vesicles of cellular origin always observed during the formation of this layer. This mineralization process takes place progressively, closely following the elaboration of the organic matrix in the scale periphery. The outer limiting and internal layers of the scale are developed after the external layer has been formed. A mineral substance is deposited without the mediation of matrix vesicles, but in contact with the previously mineralized external layer. This type of mineralization is called subsequential. However, the mineralization of the outer limiting layer closely follows the secretion of a collagen-free organic matrix and is thus different from the mineralization of the internal layer in which the calcification front remains remote from the collagen matrix surface and corresponds to a delayed mineralization process. The isolated calcifications (Mandl's corpuscles) which develop in the unmineralized laminae of the internal layer are mineralized in the absence of matrix vesicles and without making contact with a pre-existing calcified tissue, probably by a heterogeneous nucleation of the collagen fibrils.

Mineral substance of bone tissue and of experimental cutaneous calcinosis in rats: chemical analysis and ESR study

The evolution of the mineral constituents of subcutaneous calcinosis induced in rats by topical calciphylaxis was studied by the method of quantitative chemical analysis, and after treatment with excited gases by electron spin resonance (ESR) analysis. Chemical data show that the genesis of the subcutaneous calcinosis does not significantly alter the concentration of Ca, P, F, CO3, Mg, and Fe in the mineral phase of the femoral bone of calciphylactic rats. In the calcinosis an important increase of the fluoride concentration is noticed in function of the time after challenging. There is also a high concentration of Mg2+ ions in the early stages of the experimental calcification. Iron injected for the challenging is continuously present in the calciphylactic tissue after this treatment. This suggests that subcutaneous calcinosis might be a means of fixing certain heavy metal ions. After treatment with excited gases, the proportions of the trapped CO33- and O3- radicals are of the same order of magnitude in calciphylactic tissue after 12 days and observations in bone mineral. These suggest that after 12 days the mineral of the calciphylactic tissue has a crystalline state close to that of bone.

Effects of hormones on osteocyte function and perilacunar wall structure

Microradiographical and ultrastructural aspects of periosteocytic lacunae are determined by osteocytic activity, lacunar modeling and perilacunar miniremodeling in particular. The miniremodeling activity is constituted by two alternating processes: osteolysis and osteoplasis. Modifications of lacunar shape and size and of perilacunar wall ultrastructure, caused by a direct or indirect effect of certain hormones on osteocytic activity, were observed. The lacunar modeling alterations, particularly in cases of VDH or PTH deficiency, result in an irreversible impaired calcification of the lacunar walls and consequently, mottled lacunae. The alterations of periosteocytic osteolysis are characterized by an increase in number of enlarged lacunae and/or by increased magnitude of this lacunar enlargement. Usually observed as an effect of PTH and VDH, these alterations can also be induced by GC, T4, PG. On the other hand, CT causes a decrease in periosteocytic osteolysis. Periosteocytic osteoplasis is characterized by perilacunar bone formation of various aspects and is known to be stimulated by CT. The osteocytic response to hormones is a function of concentration and not of time; it is transient and not integrative. It can be concluded that none of the perilacunar wall modifications observed is characteristic of any particular hormonal effect or metabolic bone disease.

Metal-dielectric photosystems

Thin film photosystems based on copper doped lead iodide are presented. A photodecomposable Fabry-Perot type interference filter is described and also a cerment system in which copper and lead iodide are evaporated simultaneously. These systems do not require any development, and additional information can be added subsequent to the first exposure. The proposed systems are generalizable to several metals and dielectrics.

Fabrication of metal-dielectric interference filters: a simple method

A simple and direct method for the fabrication of metal-dielectric Fabry-Perot interference filters is proposed. This phase-correction method does not require any complex calculations, and the monitoring is done directly on the system in formation. Experimental filters have been realized and are compared with the theory.

Use of a Fresnel zone plate for optical image formation with short wavelength radiations

The feasibility of optical systems for short wavelength radiations ranging from the near uv to soft x rays is supported by theoretical and experimental arguments. The major problem of absorption of these radiations by materials has been overcome in the near and middle uv by using the lens properties of a Fresnel zone plate generated on a thin self-supporting film. In typical experiments with narrow field objects, it is shown that the zone plate behaves like a diffraction-limited lens, the gain in resolution is noticeable as the wavelength decreases, the use of the third-order focus improves the resolution of the system, and under certain conditions the depth of field can be increased without loss of resolution. The chromatic aberrations of the zone plate are not restrictive for a large number of applications.

[Cutaneous calcinosis induced by topical calciphylaxis in rats. I. Ultrastructural aspcts]

Skin calcification induced by topical calciphylaxis was provoked by a subcutaneous injection of iron chloride in rats previously sensitized by D.H.T. and studied by electron microscope. The evolution of the calciphylatic response can be resumed as follows: -- early appearance of numberous granules in the mitochondria of the cells of the connective tissue; their inorganic nature was revealed by microincineration and it is highly probable that they are a reserve of mineral ions; -- between the 6 hr, and the 18 hr, stages the interfibrillar matrix contained rounded vesicular structures, enclosed by a triple mambrane, which must surely be of cellular origin; they progressively incorporated more and more mineral particles which confirm their primordial role in the initial phases of mineralization; -- from the 14 hr. stage onward, mineral rodlets composed of chains of little dots appeared in the intercellular matrix and then on the collagen fibrils, probably in contact with the mucopolysaccharides; -- starting at the 24 hr, stage, the mineralization progressed without a vesicular intermediary forming increasingly dense and widespread plaques; the presence of needles of homogenous aspect indicated the appearance of a crystalline mineral deposit; an intrafibrillar mineral deposit becomes visible later. These results are compared with those obtained previously in other studies of experimental or pathological calcinosis and of mineralization of skeletal tissues.

Etude cinétique du système Cu(II)–adénine

The kinetics of formation and dissociation of Cu(II)–adenine complexes have been studied by stopped flow and relaxation methods.Between pH 3.5 and 5 the formation of Cu(II)•aH is too fast to be measured; formation of Cu(II)•(aH)2 has been studied and rate parameters have been determined. At pH < 3 protonated species make an important contribution to measured reaction rates. In basic media two different complexes have been investigated. The exchange reaction with EDTA proceeds by two parallel reaction paths.The mechanism of these reactions is discussed and compared with that proposed for the Cu(II)–adenosine system.La cinétique de la formation et de la dissociation de divers complexes Cu(II)–adénine a été étudiée par les méthodes de la relaxation thermique et du "flux stoppé".

Etude cinétique des systèmes Cu(II)•Adénosine et Cu(II)•D-Ribose

The kinetics of the formation and dissociation of Cu(II) complexes of adenosine have been determined in acidic and basic medium. In acidic medium, the complex is formed between the Cu(II) and the adenine base and the kinetic parameters have been obtained in this case using a temperature jump method. In basic medium, only the dissociation of the complexes could be studied by a stopped-flow method, by addition of EDTA or strong acid solutions. In these complexes, Cu(II) is bridged with ribose hydroxyls. Finally, D-ribose has also been studied for comparison in the same conditions. The mechanism of these reactions is discussed.

Cinétique de relaxation des complexes Ce(IV).alcool

Relaxation kinetics of Ce(IV). alcohol complexes has been studied. The rate constants of formation and dissociation have been determined and are found to depend on the nature of the alcohol: primary > secondary > tertiary. In addition, there is an increase in the rate with acidity; a mechanism is proposed to explain this.