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PubMedDate not supplied

Epiphyseal distraction and centrally located bone bar: an experimental study in the rabbit.

The purpose of this study was to analyze the force required for an epiphysiolysis in vitro in the distal femoral growth plate of rabbits with different sized central physeal bone bars. The bars were operatively induced by drilling through the physis. An epiphyseal distraction was then performed, and the response was evaluated. Forty rabbits (67 femurs) divided into five groups were used for experimentation. Group A had not been operated on and manifested no physeal bone bridge. Groups B, C, D, and E manifested some bone bridges obtained surgically by drills 2, 2.5, 3.5, and 4.5 mm in diameter, respectively. The average force required to obtain an epiphysiolysis is not statistically significant in the different groups. However, we noted that the epiphysiolysis differed depending on the diameter of the surgically performed bridge. Group E was Salter-Harris type II fractures, whereas groups A, B, and C were type I fractures. Group D comprised both types.

Animals↗
PubMedDate not supplied

Epiphyseal growth after pinning of slipped capital femoral epiphysis.

Seventy-seven hips in 61 patients (mean age, 13 years) with slipped capital femoral epiphysis treated with in situ pinning were retrospectively evaluated to determine the frequency and magnitude of epiphyseal growth after pinning. Threaded Steinmann pins, Knowles pins, and cannulated screws were used. Evidence of the epiphysis "growing off" the pins was seen in 29 and 18% of the hips treated with Steinmann and Knowles pins, respectively. No hips with cannulated screws continued to grow after surgery. The use of one cannulated screw in the treatment of mild and moderate slipped capital femoral epiphysis is recommended.

Adolescent↗
PubMed2001

Transphyseal osseous bridges in experimental osteonecrosis of the femoral head of the rat. Histologic study of the bony bridges connecting the epiphyseal with the metaphyseal bony trabeculae through gaps in the physeal cartilage.

In view of the lifelong persistence of the physis, the femoral head of rats may serve to model Perthes disease and slipped capital femoral epiphysis. To produce osteonecrosis, the blood supply of one femoral head of 133, 6-month-old animals was severed by circumferentially incising the periosteum of the neck and cutting the ligamentum teres. The rats were killed 7 days to 90 days postoperatively. Associated with resorption of the necrotic bone and marrow, remodeling of the epiphysis was characterized by an ingrowth of vascularized fibrous tissue, formation of new bone and some cartilage, architectural deformation and flattening of the head. In 22 of 83 rats killed 30 days or more postoperatively, gaps in the continuity of the physeal cartilage were occupied by osseous bridges, connecting newly formed epiphyseal bony trabeculae with either the preexisting or newly formed metaphyseal osseous trabeculae. This healing mode may follow ischemic death of physeal chondrocytes or be owing to another mechanism, e.g., release of mediatory substances of inflammation. These findings raise the possibility that fixation of the healing epiphysis of a child's previously necrotic femoral head to the metaphysis occurs by transphyseal osseous growth in cases in which the physis is involved in the necrotic process.

Age Factors↗
PubMed1985

[Effectiveness of conservative treatment following distal radius epiphyses injuries].

From 1966 to 1978, 122 infants and children suffering from injuries of the distal radial epiphysis were treated by reposition and repeated reposition. 68 of them were followed-up from 2 to 13 years later. In most cases spontaneous correction of remaining deformities by growth could be demonstrated. This remodelling of angulation depends on type and extent of the epiphyseal injury, the age of the patient and the time gone after the accident.

Adolescent↗
PubMed1984

Experimental epiphyseal separation by torsional force.

Separation of the proximal tibial epiphysis from the metaphysis by torsional force was experimentally studied using cadaver bone preparations from 19 adolescent sheep. The energy needed to displace the epiphysis increased in correlation with an increase in the age of the animal. The separated epiphyseal and metaphyseal surfaces were examined using scanning electron microscopy. In the younger animals the separation line passed through the area of hypertrophied chondrocytes. In the animals more near skeletal maturity the separation occurred in a more sinuous fashion and also through spongious bone.

Age Factors↗
PubMed1977

Fractures of the distal femoral epiphyses. Factors influencing prognosis: a review of thirty-four cases.

In a review of thirty-four fractures through the distal femoral epiphyseal plate followed for an average of four years, limb-length discrepancy of 2.0 centimeters or more (measured roentgenographically) occurred in 36% and varus or valgus deformity measured as a difference of 5 degrees or more between the involved and uninvolved extremities occurred in 33%. Reconstructive procedures (osteotomy, epiphyseodesis, or both) were required in 20%. Limitation of knee motion (eleven patients), ligament laxity (eight patients), and quadriceps atrophy (five patients) were also observed. Prognoses made on the basis of the Salter-Harris classification alone were not reliable. The development of deformity appears to be related to the degree of initial displacement of the fracture, the exactness of the reduction, and the type of fracture.

Adolescent↗
PubMed1998

A large family with multiple epiphyseal dysplasia linked to COL9A2 gene.

We describe a large family, including 54 affected individuals, with multiple epiphyseal dysplasia (MED) with involvement of the peripheral joints only. In this family, a mutation in the COL9A2 gene was detected. Every affected person has involvement of the knee joints. Other involved joints are the elbow, ankle, wrist, hand, and feet joints. Involvement of the shoulder or hip joints is never seen after adolescence. The height of the affected individuals is short to normal; spinal involvement is never seen. The penetrance of the gene is complete. However, the expression of the gene is highly variable.

Adolescent↗
PubMed1999

Identification of nine novel mutations in cartilage oligomeric matrix protein in patients with pseudoachondroplasia and multiple epiphyseal dysplasia.

Pseudoachondroplasia (PSACH) and multiple epiphyseal dysplasia (EDM1) are allelic disorders caused by mutations in the gene encoding cartilage oligomeric matrix protein (COMP). PSACH is a dominant condition characterized by disproportionate short stature, joint laxity, and early-onset osteoarthritis. EDM1 is a less severe skeletal dysplasia associated with average to mild short stature, joint pain, and early-onset osteoarthritis. COMP is an extracellular matrix protein present in cartilage, ligament, and tendon tissues. Here, we report on nine novel mutations in COMP causing PSACH and EDM1. Four of these mutations are in exons 13C and 14 where no previous mutations had been reported. One of those mutations was identified in two separate EDM1 families. In addition, we have identified the first case of PSACH resulting from an expansion of the five aspartates in exon 17B. We are also reporting a mutation in a third PSACH family with somatic/germline mosaicism. Therefore, this report increases the range of mutations that cause PSACH and EDM1 and provides additional regions to target for mutational analysis.

Achondroplasia↗
PubMed1998

Induction and characterization of metallothionein in chicken epiphyseal growth plate cartilage chondrocytes.

Following exposure to cadmium or zinc, chickens were sacrificed and the liver, kidney, and bone epiphyseal growth plates harvested. When cytosolic extracts of the growth plate cartilage were fractionated by gel filtration chromatography, a protein with high metal-binding capacity and low ultraviolet (UV) absorbance eluted in the same position as liver metallothionein (MT) and a MT standard. Cd or Zn treatment resulted in a 25-fold or 5-fold induction in growth plate MT, respectively. In liver the greatest level of MT induction was seen with short-term Cd exposures. In contrast, MT levels in the growth plate increased as the duration of Cd exposure increased. Induction of MT in growth plate chondrocyte cell cultures was observed for media Cd concentrations of > or = 0.1 microM and Zn concentrations of > or = 100 microM. Basal and inducible levels of MT declined through the culture period and were lowest in the terminally differentiated mineralized late stages of the culture. Alkaline phosphatase activity was also lowest in the late-stage cultures, while total cellular protein increased throughout the culture period. Treatment of chondrocytes with Zn prior to Cd exposure resulted in a protective induction of MT. Pre-treatment of chondrocytes with dexamethasone resulted in suppressed synthesis of MT upon Cd exposure and greater Cd toxicity. Both Cd and Zn resulted in significantly increased levels of MT mRNA in chondrocyte cell cultures. Dexamethasone treatment resulted in an approximate 2- to 3-fold increase in MT mRNA. This is contrary to the finding that MT protein levels were decreased by dexamethasone. The findings suggest that an increased rate of MT degradation in dexamethasone-treated and late-stage chondrocyte cultures may be associated with the terminally differentiated phenotype.

Animals↗
PubMed1989

Epiphyseal dysplasia, microcephaly, nystagmus, and retinitis pigmentosa.

In 1975, we reported two brothers with epiphyseal dysplasia, microcephaly, and nystagmus; one of them also had mild mental retardation. Here we present information on the natural history, particularly with respect to the development of a new visual problem, namely, retinitis pigmentosa.

Adolescent↗
PubMed1990

Mental retardation, short stature, almond-shaped eyes, small downturned mouth and coned epiphyses: a new case of Hunter-Fraser syndrome.

A 21-year-old male with mental retardation, short stature, almond-shaped eyes, small downturned mouth, and coned epiphyses is presented. The clinical presentation, as well as the metacarpal phalangeal pattern profile, was similar to the affected members of a family reported by Hunter et al.: (Hunter et al.: J Med Genet 14:430-437, 1977). In addition, many features of our patient resembled Ruvalcaba syndrome. However, skeletal abnormalities were different. A reciprocal translocation was also observed in 3 members of our patient's family.

Abnormalities, Multiple↗
PubMed1982

Cone-shaped epiphyses in Japanese children.

Cone-shaped epiphyses (CSE) are reported in left-hand radiographs of a sample of 1,399 otherwise normal Japanese children aged 5-11 years. CSE occurred in only three centers: distal thumb, mid-index finger, and mid-fifth finger. The overall frequency of 23% shows a female bias (32% to 16%), which disappears when mid-5 cones are excluded. Chi-squared analyses show significant gender bias for mid-5 cones alone or in combination with the other phalanges, and show significant center associations: CSE in distal-1 and/or mid-2 are more common in association with mid-5 cones than they are without mid-5 cones. The CSE female bias in mid-5 is essentially unchanged across age-cohorts when bone-age is controlled for precocity, and no significant trends in CSE frequency with age are noted for either gender.

Age Factors↗
PubMed1979

Ultrastructural localization of histones in epiphyseal chondrocytes.

Epiphyseal growth plate chondrocyte nuclei of growing rats were studied for histone content using the ammoniacal silver technique. This stain, which is specific for the demonstration of the arginine-rich fractions of histones, revealed that growth plate nuclei vary in their histone content. Nuclei of cells of the proliferating zone revealed a significantly greater amount of postformalin ammoniacal silver deposit consistent with the presence of arginine-rich histones.

Animals↗
PubMed1981

A freeze-fracture study of avian epiphyseal cartilage differentiation.

The morphological features of avian epiphyseal cartilage have been investigated by freeze-fracture techniques. Progressive changes occurred in both the cells and the matrix during differentiation. Chondrocytes changed in shape from small flattened cells with few, short cellular processes, to enlarged ovoid cells with numerous long processes often associated with extracellular vesicles. In the matrix these vesicles appeared first in the cellular lacunae, then in the extralacunar matrix, becoming larger and more numerous. Large membrane-associated particles (MAPS) were seen on the p faces of the plasmalemma. These became progressively concentrated on and around the cellular processes, with few large MAPS being seen on the e face. Similar distribution of MAPS was seen in the matrix vesicles. Domains of hydrated proteoglycan aggregates were manifest as regular fracture patterns in the extralacunar matrix of the upper regions of the plate. Collagen fibrils progressively increased in size and state of aggregation, often being associated with matrix vesicles and in the end, with long plate-like mineral crystals. These findings, while in basic agreement with patterns observed with TEM, reveal important new features concerning cellular and matrix structure during cartilage differentiation.

Animals↗
PubMed1987

Improved ultrastructural preservation of epiphyseal chondrocytes by the freeze-substitution method.

The ultrastructure of epiphyseal chondrocytes was studied following quick-freezing and freeze-substitution, and was compared to that of cells fixed with aqueous aldehydes. The former approach provided an improved ultrastructural preservation whereby every type of chondrocyte exhibited a smoother cell contour. The plasma membrane as well as intracytoplasmic membranes revealed a trilaminar substructure. The intracytoplasmic ground substance was composed of flocculent materials which were in direct contact with the inner leaflet of the plasma membrane. Within the extracellular matrix the proteoglycan network adhered to the outer leaflet of the plasma membrane. Whenever cellular shrinkage took place, the flocculent matrix within the cytoplasm and the proteoglycan network in the pericellular matrix disappeared. The contents of the RER, the Golgi apparatus, and the intracellular vesicles and vacuoles were well retained. In the proliferative zone, the Golgi saccules of young cells contained a thread-like structure showing a clear periodicity. The cytoplasmic vesicles and vacuoles showed marked variation in their electron density. Intramitochondrial granules were sensitive to aqueous treatments, as evidenced by the observation that they disappeared after either floating on water or staining with aqueous solution. In the calcifying zone, mitochondrial granules were noted within hypertrophic chondrocytes, a feature that was not observed following conventional processing. Cytoskeletal elements were well preserved in all types of cells. A dense microfilamentous network occupied the pericellular cytoplasm. Bundles of microfilaments were seen in the cellular peripheral processes. Microtubules were distributed throughout the cytoplasm, and the Golgi complex was intimately associated with the microtubule network; it appears that the secretory processes are involved with the microtubules.

Animals↗
PubMed1983

Correlation between distribution of cytoskeletal proteins and release of alkaline phosphatase-rich vesicles by epiphyseal chondrocytes in primary culture.

Matrix vesicles, extracellular microstructures known to be involved in endochondral calcification, are rich in alkaline phosphatase and have been shown to contain actin. The mechanism of matrix vesicle formation in chondrocytes is not well understood. Chondrocytes from the epiphyseal growth plate, when grown in primary culture, elaborate alkaline phosphatase-rich vesicles. We examined the distribution of the cytoskeletal proteins actin, myosin, tubulin, and vinculin at various time-points during culture using indirect immunofluorescent labeling. Concomitantly, the production of alkaline phosphatase-containing matrix vesicles was also followed. Cell morphology changed noticeably at two distinct stages during the 22-day culture period: Immediately after release from the growth plate the cells were rounded, but after 4 days of culture they began to spread out and acquire irregular shapes with distinct filopodia. By 13 days, as the cells attained confluency, they reacquired a rounded, polygonal appearance. At all time-points, tubulin was seen as a dense network of microtubules radiating from the perinuclear region throughout the cytoplasm toward the cell periphery. Initially actin was seen in filamentous form, but displayed a punctate distribution focused at contact points during the cell-spreading stage of culture. After confluency, actin was concentrated at cell-cell junctions. Initially, vinculin was diffusely distributed, but became focused in multiple adhesion plaques and at the termini of filopodia during the cell-spreading stage of culture. Following confluency vinculin became concentrated at cell-cell junctions. Myosin was observed at all time-points in small, intensely localized focal points in the cytoplasmic region of the cells and was consistently absent from the nuclear and peripheral regions. The amount of myosin in the cells increased steadily with time in culture. Elaboration of alkaline phosphatase-rich vesicles, which corresponded closely with the rounded morphology of early and late stages of culture, may be correlated with contact inhibition.

Actins↗
PubMed1987

Microvascular organization at the epiphyseal-metaphyseal junction of growing rats.

The microarchitecture of the rat metaphyseal nutrient artery, the major blood supply to the calcifying epiphyseal growth plate, was studied by light microscopic serial sections, model reconstruction of serial sections, and scanning electron microscopy of plastic corrosion castings. These techniques illustrate how the metaphyseal artery undergoes extensive arborization and anastomosis upon route through the metaphysis. From this vascular network, closed capillary sprouts abut hypertrophic chondrocytes bordered by scaffolds of mineralized matrix.

Animals↗
PubMed2001

Effects of zinc on cell proliferation and proteoglycan characteristics of epiphyseal chondrocytes.

Zinc has been postulated as an important nutritional factor involved in growth promotion; however, the cellular mechanisms involved in the effects of zinc on linear growth remain to be elucidated. This study was conducted to evaluate the effects of zinc on the proliferation rate of epiphyseal growth plate chondrocytes and on the structural characteristics of the proteoglycans synthesized by these cells. For these purposes, hypertrophic and proliferating chondrocytes were isolated from the tibiae of 1- and 5-week-old chickens, respectively. Chondrocytes were cultured under serum-free conditions and primary cultures were used. The results showed that zinc stimulated proliferation by 40-50% above the baseline in the case of proliferating chondrocytes, but it had no effect on hypertrophic chondrocytes. Zinc had neither any effects on mean charge density of proteoglycans synthesized by hypertrophic chondrocytes nor in their hydrodynamic size. In contrast, zinc induced an increase in mean charge density and a decrease of hydrodynamic size of proteoglycans synthesized by proliferating chondrocytes. In both cell types zinc had no effect on the composition and hydrodynamic size of the glycosaminoglycan chains. The increased ability of proliferating chondrocytes cultured in the presence of zinc to synthesize 3'-phosphoadenosine 5'-phosphosulfate (PAPS) could be explained by the induction of enzymes participating in the sulfation pathway of proteoglycans. Therefore, the increase in mean charge density of proteoglycans observed in this study may be explained by an increase of the degree of sulfation of proteoglycan molecules. We speculate that the effect of zinc on linear growth may be explained at a cellular level by: a) an increase in proliferation rates of proliferating chondrocytes, and b) increased synthesis of highly charged proteoglycan molecules which decreases mineralization.

Animals↗