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PubMed1983

Ca-enriched amorphous mineral deposits associated with the plasma membranes of chondrocytes and matrix vesicles of rat epiphyseal cartilage.

Electron microscopic study of tibial epiphyseal plates of young growing rats revealed amorphous-appearing electron dense deposits 5-35 nm in diameter, associated with the plasma membranes of more than 43% of the proliferative zone chondrocytes. Hypertrophic zone chondrocytes, however, revealed no plasma membrane-associated amorphous-appearing deposits. The membrane-associated densities were observable in unstained sections of tissues fixed in glutaraldehyde alone and in tissues double-fixed with glutaraldehyde and osmium tetroxide, and were extracted from ultrathin sections floated on neutral aqueous solutions of 4% ethyleneglycol bis-(beta-aminoethyl ether) N,N'-tetraacetic acid (EGTA) for one-half hour. Energy dispersive X-ray analysis of the densities in scanning transmission electron microscope (STEM) mode revealed the presence of Ca, suggesting that the membrane-associated amorphous-appearing deposits are Ca-enriched. Similar deposits were observed in the membrane of matrix vesicles present in the longitudinal cartilaginous septae in the hypertrophic zone. Four types of matrix vesicles were encountered in the longitudinal cartilaginous septae; one type with amorphous-appearing deposits, another with crystallites, a third type with both amorphous-appearing and crystalline-like deposits, and a fourth that is empty. These observations are interpreted to indicate that chondrocytes of the reserve and proliferative zones play a direct role in mineralization by elaborating amorphous mineral deposits along their plasma membranes. These deposits are incorporated into budding matrix vesicles, which then play a role in the initiation of mineralization by supporting the spontaneous phase transformation of amorphous-appearing mineral to crystalline mineral.

Animals↗
PubMed1980

Calcium incorporation in matrix vesicles isolated from chicken epiphyseal cartilage.

Matrix vesicles isolated from chicken epiphyseal cartilage displayed an uptake of Ca2+ which was linear with time and the amount of vesicle protein. The matrix vesicles stimulated the incorporation of Ca2+ even at very low Ca x P, suggesting that they could bind Ca2+ and/or increase the local Ca x P to the metastable level. This uptake was abolished by EDTA or heating, and partially inhibited by cysteine, to the same extent as the hydrolysis of ATP. There was also a certain uptake of Ca2+ without added phosphate, this being stimulated by ATP up to 3 mmol, but diminishing again with higher concentrations. The presence of ATP failed to stimulate the uptake of Ca2+ more than an equimolar amount of phosphate in the form of inorganic KH2PO4. Mg2+ activated the hydrolysis of p-nitrophenylphosphate at pH 10.5, and both Mg2+ and Ca2+ the hydrolysis of ATP from pH 7 to 9.5. Paradoxically, the omission of Mg2+ stimulated the uptake of Ca2+ several-fold.

Adsorption↗
PubMed1981

Ultrastructure of the rat epiphyseal growth plate following chronic ethanol ingestion.

We have previously demonstrated that ethanol has a direct toxic effect on the rat skeleton characterized by decreased trabecular bone volume. In the present study, we examined the ultrastructure of the distal radial epiphyseal growth plates in these same animals. Eight weeks of ethanol administration to 12 male rats results in serum alcohol levels of 140 mg/dl but did not alter the width or light microscopic appearance of the radial growth plate. Quantitative electron microscopy failed to demonstrate morphologic evidence of toxicity in the skeletal cells. We conclude that although ethanol appears to have a direct effect on rat bone characterized by enhanced resorption, toxicity is not attended by ultrastructural changes in the skeletal cells.

Animals↗
PubMed1982

Immunohistochemical demonstration of extracellular carbonic anhydrase in epiphyseal growth cartilage.

The distribution of carbonic anhydrase isoenzymes C and B in the rate epiphyseal growth cartilage was demonstrated by an immunohistochemical method. The isoenzymes were found in different locations. Isoenzyme C was in the extracellular matrix of the hypertrophic and calcifying cartilage, and no reaction was observed in the chondrocytes. In contrast, the antiserum against isoenzyme B revealed only a weak cellular staining. This supports the hypothesis that carbonic anhydrase isoenzyme C, which is the high-activity form, changes the pH in the extracellular fluid of calcifying cartilage, favoring the deposition of calcium phosphate.

Animals↗
PubMed1979

Matrix vesicles in chicken epiphyseal cartilage. Separation from lysosomes and the distribution of inorganic pyrophosphatase activity.

The extracellular matrix vesicles from epiphyseal cartilage of chickens were isolated by differential centrifugation. The matrix vesicles obtained showed considerable activity of lysosomal enzymes. This appears to have been due to lysosomal contamination because when we used a new density gradient medium (Percoll), the lysosomal enzyme activities and the activity of alkaline phosphatase could be totally separated. Electron microscopy of the alkaline phosphatase-rich fraction showed matrix vesicle-like structures. Phosphatase activities of the cells and matrix vesicles were further studied by Sephadex G-200 gel filtration. Specific magnesium-activated inorganic pyrophosphatase, distinct from nonspecific alkaline phosphatase, could be demonstrated in the cellular fraction. No such separate activity could be demonstrated in the matrix vesicle fraction, and it is supposed that the pyrophosphatase activity in the matrix vesicles originates from the alkaline phosphate.

Alkaline Phosphatase↗
PubMed1976

The metabolic heterogeneity of glycosaminoglycans of the different zones of the epiphyseal growth plate and the effect of ethane-1-hydroxy-1, 1-diphosphonate (EHDP) upon glycosaminoglycan synthesis in vivo.

The synthesis of total and unextractable glycosaminoglycans of rabbit epiphyseal growth plate was studied by determination of the incorporation in vivo of 35S-sulphate into various glycosaminoglycans separated by microfractionation procedures using CPC and ECTEOLA columns. In the narrow hypertrophic zone, hyaluronic acid and chondroitin sulphate of low molecular weight were found to be unextractable with 3M guanidinium chloride for 24 h, thus being firmly bound within the tissue. While the unextractable chondroitin sulphate showed a sharply reduced synthesis rate in the hypertrophic zone compared with that in the columnar and resting zones, a rapid increase in the synthesis of extractable chondroitin sulphate toward the calcification front is indicated. At microfractionation, solubility profiles indicated that the unextractable chondroitin sulphate was of predominantly lower molecular weight and/or charge density compared to that of the whole tissue, most evident in the hypertrophic zone. The distribution pattern of incorporated 35S showed a close correspondence to the distribution of the various chondroitin sulphate fractions both for extracted and unextracted tissue. In the hypertrophic zone, higher radioactivity was found for chondroitin sulphate of predominantly low molecular weight and/or charge density in extracted compared to unextracted tissue. Low doses of EHDP caused no change of distribution of the various glycosaminoglycans but generally inhibited their synthesis.

Animals↗
PubMed1975

Calcium localized in juxtanuclear granules of epiphyseal chondrocytes with a dilute glyoxal bis(2-hydroxyanil) solution.

The glyoxal bis(2-hydroxyanil) (GBHA) method for staining labile calcium deposits in chondrocytes was modified. Fresh blocks of epiphyseal cartilage stained in this dilute GBHA solution revealed calcium in the juxtanuclear Golgi vesicles, each approximately 1 mu in diameter. Prolonged staining revealed previously described 0.5 mu granules throughout the cytoplasm which tended to mask the juxtanuclear reaction. The red GBHA reaction product was believed to be a chelate of calcium since it was removable with EGTA, and stable in Na2CO3 and KCN solution. When the tissue blocks stained with the dilute GBHA solution were restained with the original concentrated GBHA solution, refractile bodies containing red GBHA-positive granules were revealed at the periphery of the hypertrophied chondrocytes. The presence of calcium in the juxtanuclear Golgi vesicles and in the pericellular refractile bodies may indicate that the Golgi is involved in the transport of minerals to the matrix.

Aminophenols↗
PubMed1984

[Biodynamics of the epiphyseal plate].

The architecture of the collagenous fibers in epiphyseal plates of infantile long bones is ordered in a manner that tensile load is able to be transformed in compressive stress and reverse. This system can be classify in the theory of the formation of the sustentacular tissue by mechanical forces of Roux, Benninghoff and Pauwels.

Biomechanical Phenomena↗
PubMed1988

Rat epiphyseal cells in culture: responsiveness to bone-seeking hormones.

Cell cultures derived from young rat epiphyseal cartilage were grown for approximately 2 wk in BGJb medium supplemented with 10% fetal bovine serum to reach confluence. These cells were identified as chondrocytes as checked by morphology, the presence of alkaline phosphatase, and a positive type II collagen antibody reaction. The cells also responded to different hormonal treatment. Parathyroid hormone (PTH) increased cyclic AMP production by 50% within 15 min of treatment, whereas prostaglandin E2 (PGE2) caused an increase of 160%. Calcitonin (CT) did not affect cAMP production in these cells. DNA synthesis 24 h after hormonal treatment was increased by PTH (2.5-fold) and PGE2 (2-fold), but not by CT. Among the vitamin D metabolites, 24,25(OH)2D3 increased significantly the [3H]thymidine incorporation into DNA, whereas 1,25(OH)2D3 effect was minimal. These results provide evidence for the use of these cell cultures as a model for cartilage in vitro when studying biological and hormonal responsiveness.

24,25-Dihydroxyvitamin D 3↗
PubMed1996

Epiphyseal lengthening operation--an improved technique.

An improved method of epiphyseal lengthening operation and subsequent outer fixation are presented on the basis of experience in 30 cases. The operative technique is described in detail, including the different options of separative traction and osteotomy at subtrochanteric, distal part of the upper femur and lower tibial levels. The physiological and histological research concerning this method is discussed. The authors believe that this procedure is better than the other methods.

Adolescent↗
PubMed2006

Arthroscopic assisted reduction and internal fixation of lateral femoral epiphyseal injury in adolescent soccer player: a report of one case.

Ligament injuries are more common than fractures in adolescents. We operated on an adolescent soccer player, who had a lateral femoral epiphyseal injury using arthroscopic-assisted reduction and percutaneous internal fixation. During second-look arthroscopy 2 years after the first operation, there was articular cartilage congruity, without any visible step-off. The axial alignment did not reveal any residual valgus deformity.

Adolescent↗
PubMed2003

Skeletal scintigraphic appearance of an auto-transplanted osteoarticular plug: epiphyseal transplant.

Nuclear medicine bone scan is an essential diagnostic imaging tool both for the diagnosis and staging of bone tumors and in the follow-up of these patients. It is very important that we be able to discriminate between normal variants, changes related to altered physical stress, and recurrent disease in order to interpret the bone scan meaningfully. We wish to report the appearance of the isotope bone scan, technetium 99m-labeled methylene diphosphonate ((99m)Tc-MDP), associated with an auto-transplanted osteoarticular plug (epiphyseal transplant) performed following limb amputation. This reconstructive surgery can give a potentially misleading appearance on the nuclear medicine bone scan if one is unfamiliar with this surgical technique.

Adolescent↗
PubMed1998

Phalangeal cone-shaped epiphyses of the hand: their natural history, diagnostic sensitivity, and specificity in cartilage hair hypoplasia and the trichorhinophalangeal syndromes I and II.

Phalangeal cone-shaped epiphyses are an ideal object for the radiologist to study with temporal reasoning, to examine their shape, diagnostic usefulness, natural history and effect on pathophysiology. Radiographs of the hands of 60 patients with cartilage hair hypoplasia (CHH), 69 with trichorhinophalangeal syndrome I (TRP I) and 11 with TRP II were examined, including 26 longitudinal observations. The early phases of cone development were recorded. In CHH a characteristic mesophalangeal type of cone in 42/47 patients of the "Age Suitable for Classification" (ASC) was detected. All 46 TRP I and 9 TRP II patients in the ASC had the previously described mesophalangeal cone type 12. However, 1/4 of these TRP I and all TRP II cases presented a milder variant of type 12: type 12 A. A complex sequence of secondary changes in the proximal interphalangeal joints in TRP I leading eventually to subluxation was recorded. It can be concluded that in the ASC the cones described are highly sensitive but not specific diagnostic indicators. In infancy and early childhood, other phalangeal changes were found, which may be of diagnostic help.

Adolescent↗
PubMed1998

Trichorhinophalangeal syndrome type I in monozygotic twins discordant for hip pathology. Report on the morphological evolution of cone-shaped epiphyses and the unusual pattern of skeletal maturation.

A pair of monozygotic twin girls with trichorhinophalangeal syndrome type I (TRPS I), followed from 8.3 to 16.1 years of age, is described. Both showed typical dysmorphic features and severe short stature, but only one had Perthes-like changes in the right capital femoral epiphysis. The radiographic findings and evolutionary changes of phalangeal cone-shaped epiphyses (PCSE) of the hands are illustrated in this report. The unusual bone maturation and growth of the twins are also described. Both presented poor growth and delayed bone age until about 13 years, followed by marked acceleration of bone age and stunted pubertal height spurt.

Adolescent↗
PubMed2006

Posterior sternoclavicular epiphyseal fracture-dislocation with delayed diagnosis.

Posterior sternoclavicular joint dislocations and epiphyseal fractures are relatively rare injuries. We present a case report of a 16-year-old male who presented with a 10-day delay in diagnosis. The medial clavicular fragment was widely displaced and rested against the cervical vertebral body. Despite the degree of displacement, the patient had very few symptoms, and the diagnosis was not appreciated in the emergency department and became apparent at 10-day clinic follow-up. Treatment consisted of attempts at closed reduction, which were not successful. Open reduction was performed and the repair done with strong sutures. At 1-year follow-up the patient is doing well without any symptoms. A literature review consisting of anatomy, ossification patterns, classification systems, diagnosis and associated symptoms, imaging recommendations, treatment recommendations, outcomes, and complications is included.

Adolescent↗
PubMed2005

Carpals and epiphyses of radius and ulna as age indicators.

Estimation of skeletal age using radiographic images is widely used for assessing biological growth in clinical and auxological studies. The most frequent areas used for age estimation in children and adolescents are tooth and wrist/hand, both giving good results with only a low level of radiation. In particular, ossification of the carpals shows good agreement with chronological age. This study of a sample of 150 Italian children and adolescents aged between 5 and 17 years focused on analyzing the possible applications of the proportion of carpal area (Ca) mineralization as a criterion of age estimation. The ratio between the total area of carpal bones and epiphyses of the ulna and radius (Bo) and Ca was calculated. This ratio (Bo/Ca) was used for linear regression analysis. The regression model, describing age as a linear function of the ratio Bo/Ca, yielded the following equation: Age=-3.253+0.719 g+20.610 Bo/Ca, and explained 83% of the total variance (R (2)=0.83). The median of the absolute values of residuals (observed age minus predicted age) was 0.08 years, with a quartile deviation of 1.59 years, and a standard error of estimate of 1.19 years.

Adolescent↗
PubMed1997

Generalized metaphyseal modification with cone-shaped epiphyses following long-term administration of 13-cis-retinoic acid.

UNLABELLED: We report on a 6-year-old girl with short stature which developed following the administration of 13-cis-retinoic acid (a synthetic derivative of vitamin A or retinoid) for 40 months as adjunct chemotherapy for neuroblastoma. Radiographic examination suggested osteophyte formation in the cervical spine, which is the most common skeletal manifestation of retinoid toxicity [10, 11]. In addition, severe metaphyseal cupping with a cone-shaped epiphysis primarily affecting rapidly growing long bones was found, which represented impaired enchondral ossification. This epi-metaphyseal alteration, though unusually severe, was reminiscent of the premature epiphyseal closure which has been described as an adverse effect of 13-cis-retinoic acid [10-12]. Other minor skeletal changes included posterior scalloping of the vertebral bodies and increased interpediculate distances, which were related to a widened spinal canal found on CT. A literature search disclosed several primary skeletal dysplasias with superficial radiological similarities to those of the present patient. However, these entities showed significant clinical and radiological differences from our patient. CONCLUSION: The precise cause of the generalized skeletal alteration in the present patient remained unknown, but it conceivably resulted from the administration of 13-cis-retinoic acid.

Child↗