摘要:

AbstractOur purpose in this study was to assess ligament fibroblast viability after freezing by quantifying the subsequent ability of fibroblasts to synthesize collagen in vitro. Both medial collateral ligament (MCL) complexes from 40 adolescent rabbits were studied. Collagen production was determined by in vitro incubation of ligaments in3H‐proline (a collagen precursor) and subsequent analysis of3H‐hydroxyproline (a marker of newly synthesized collagen). Autoradiographs determined the distributions of ligament cell activity. All right MCL complexes served as fresh controls, providing a baseline of collagen production. Each left MCL was assigned to an experimental group and was either incubated fresh (10 animals); “killed” by drying, multiple freeze thawing, or cycloheximide (six animals); or slowly frozen at −70°C without cryoprotection (24 animals). Collagen production of rapidly thawed ligaments was studied by proline incubation at 1 day, 9 days, or 6 weeks after freezing and was compared with that of contralateral fresh controls. Results demonstrate that some cells in the substance of these rabbit ligaments retained the ability to synthesize collagen in vitro after being frozen for up to 6 weeks. Mean collagen production of frozen ligaments was decreased, but tests of mean and median values as well as ratios were statistically similar to fresh contralateral ligaments in all animals. This postfreezing ligament cell survival and collagen production after −70°C storage may have implications for ligament tr

ISSN:0736-0266    

DOI:10.1002/jor.1100060112

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractIn vitro proteoglycan (PG) synthesis and release were measured on cartilage removed from rabbit knees within 1 week of meniscectomy. Three days following partial lateral meniscectomy, 72% of the femurs and 82% of the tibias had visible ulcers. Cartilage from the weight‐bearing areas incorporated 2.0–2.9 times more35S‐sulfate in vitro than cartilage from the opposite, unoperated knees.3H‐thymidine incorporation was 2.5–3.4 times higher for surgical than control groups.35S‐sulfate incorporation by the surgical group was inhibited by 22% in the presence of 10−4MU24522, an inhibitor of rabbit chondrocyte metalloprotease (CMP).3H‐thymidine incorporation by the surgical group was inhibited by 28% by 10−4MU24522. In vitro PG release from cartilage removed 2 days after surgery was 1.6–3.7 times higher for the surgical than the control group. PG release by the surgical group after 22 h of incubation was reduced to the control level by three CMP inhibitors, U24278, U24279, and U24522. PG release by cartilage from the nonsurgical group was also reduced by these compounds at 22 h. These results suggest that both the anabolic and catabolic processes that are stimulated by surgery can be isolated in vitro and that CMP may be involved in th

ISSN:0736-0266    

DOI:10.1002/jor.1100060113

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe ability of chondrocytes to survive conditions encountered during cryopreservation depends on the responses of the cells to the physiochemical changes that result when water is removed from the environment of the cells in the form of ice. Cellular responses are therefore closely related to the osmotic permeability properties of the plasma membrane. In order to optimize the conditions for cryopreservation of chondrocytes, osmotic properties of the chondrocyte membrane were determined from the kinetics of volume change in hypertonic solutions at different temperatures. The hydraulic conductivity of the plasma membrane was 0.305 ± 0.025 μm3/μm2/min/atmosphere at 24°C, with an Arrhenius activation energy of 8.06 kcal/mol. These values are similar to those reported for other cell types, but the osmotically inactive volume of the chondrocytes (0.41 ± 0.04) was significantly higher than for other cells, implying that chondrocytes have a higher dry weight ratio or that they contain a higher proportion of osmotically inactive or bound water. These results were used to calculate the osmotic responses of chondrocytes at low temperatures and to predict that the least damaging cooling rate for isolated chondrocytes in the absence of cryoprotective compounds is 10°C/min. The ultimate goal of this study is the development of an analytical model applicable to the optimization of techniques for cryopreservation of intact cartilage and other ti

ISSN:0736-0266    

DOI:10.1002/jor.1100060114

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe computed carpal models from digital computed tomography (CT) data obtained in this study compare favorably to natural anatomy. A new application of algebraic analysis of this data provides mathematical markers from which to calculate the position and orientation of each carpal bone. When the origin of the spatial coordinates of a carpal bone is transferred to the centroid of the bone, the data can be treated as three‐dimensional pattern vectors describing its surface. It is then possible to calculate vectors that are the principal axes of the geometry. These axes provided references that were used to calculate position and orientation of the carpal bones in three wrist specimens. Comparisons of volumes, surface areas, and sizes and proportions of five computed images of each carpal bone from two of these wrists demonstrate the reliability of the technique. The analysis of CT scans of ceramics with known boundaries allows an estimation of its accuracy. The technique is well suited to the future study of normal wrist kinematic and pathological condition

ISSN:0736-0266    

DOI:10.1002/jor.1100060115

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe microcapillary infusion (MCI) technique was evaluated in monitoring pressure in the subacromial bursa in 30 shoulders in healthy volunteers. The total pressure in the bursa was studied as the volunteers held their arms at rest and as they lifted their arms and held them lifted with or without a weight of 1 kg in the hands. The pressure in the bursae at rest averaged 8 mm Hg and was found stable during a 40‐min period. When the arms were lifted, the average bursa pressure increased from 8 to 39 mm Hg. As the arms were held up, the weights were put in the hands, and the average bursa pressure then further increased to 56 mm Hg. When the infusion catheters were repeatedly flushed, during a period of 5 min and with a total of 1.2 ml of saline, the average bursa pressure doubled regardless of arm position and load in the hands. The compliance of the bursae decreased from 0.09 to 0.04 ml/mm Hg when the arms were lifted and from 0.04 to 0.02 ml/mm Hg when the arms were lifted and the hands were loaded. The MCI method was found suitable for recording pressure in the subacromial bursa during exercis

ISSN:0736-0266    

DOI:10.1002/jor.1100060116

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractStereo radiography and stereotopography were used to record simultaneously the three‐dimensional spinal and back surface shape of 141 patients with a clinical diagnosis of adolescent onset idiopathic scoliosis. Radiography confirmed 80 patients with single lateral curves (Cobb angle 5–87°); 59 with double curves (Cobb angle 5–61°). and two patients with triple curves. Orientation of each vertebra was measured by the lateral deviation from the spinal axis and the axial rotation. For each curve detected, the Cobb angle, the maximum deviation, the maximum axial rotation, and the sagittal plane curvature was measured. Topographic data were used to generate a profile of a cross‐section through the back of each vertebral level. This section was characterized by its axial rotation, deviation of its midpoint from the spinal axis, and area symmetry about the midpoint. Maximum values of these measurements in the region of each radiographic scoliosis curve were noted. Regression and correlation analysis showed (for each curve) a high correlation of apical vertebral lateral deviation with back surface axial rotation (r = 0.79) and with vertebral axial rotation (r = 0.79). The back surface rotation was less than vertebral rotation in magnitude, however, by a mean factor of 0.55. The measurement of the back surface asymmetry that gave the highest correlation with the skeletal deformity was the axial rotation. Relationships between skeletal and surface measures were similar for curves in thoracic and lumber regions and for patients with single and double curves. There is potential for clinical application of surface measurement techniques to prescription of orthoses and monitoring of changes due to progression or

ISSN:0736-0266    

DOI:10.1002/jor.1100060117

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractWe report here the biochemistry of fusion mass consolidation in sheep spines during a 1‐year period following autogenous cortical‐cancellous bone grafting and stabilization with Harrington distraction rods. Biochemical analysis of vertebral fusion mass included determination of wet weight and dry weight and quantification of glycosaminoglycan, collagen, calcium, and phosphate following extraction with neutral EDTA and proteolytic hydrolysis with papain. Our results showed that at 1 week after surgery, the fusion mass consisted of original cortical and cancellous bone graft material. The cortical bone graft was partially resistant to EDTA‐papain treatment, resulting in a residue containing hydroxyproline and mineral. At 12 weeks after surgery, the fusion mass had become a homogeneous material, which, like cancellous bone graft, was completely susceptible to treatment by EDTA‐papain. Collagen content of consolidating fusion mass was highest at 16 weeks after surgery when normalized to dry weight; glycosaminoglycan content was highest within 6 weeks after surgery. Mineral content was lowest at the 6‐week stage but by 12 weeks after surgery, it was comparable with original bone grafting material. At 24 and 52 weeks after surgery, fusion mass consolidation was characterized by an increase in the proportion of organic and mineral components resistant to EDTA‐papain. The appearance of the EDTA‐papain‐resistant material in the fusion mass coincided with formation of lamellar bone and successfu

ISSN:0736-0266    

DOI:10.1002/jor.1100060118

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractUnder development is an internal fixation plate that incorporates a piezoelectric element to generate current when excited mechanically by either weight bearing or external application of ultrasound. The intent is to deliver this current to electrodes at a fracture or osteotomy site to aid in prevention or treatment of nonunion. The present study examines quantitatively the ability of external ultrasound to generate current from small piezoelectric ceramic elements implanted in tissue. An ultrasonic transducer (2.25 MHz, 10–20 V input,<10 mW/cm2output) was employed to excite small test coupons of a piezoelectric ceramic in vitro and in vivo with various materials, including water, PVC gel, cortical bone, and living soft tissues, interposed. In all instances, it was possible to generate currents of up to 20 μA after rectification; currents up to 1 mA were achieved in some cases. The work indicates that external ultrasonic energy could effectively power small internal devices designed to stimulate bone healing, without the need for implanted batteries or percutaneous lea

ISSN:0736-0266    

DOI:10.1002/jor.1100060119

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractIn 1911, Gebhardt used a photoelastic model to relate mechanical stresses to the ossification pattern of the chondroepiphysis. Pauwels later conducted a photoelastic study using the same model geometry to develop a theory that the secondary ossific nucleus originates at a position of high‐magnitude hydrostatic pressure where the shear stresses are zero. We conducted two‐dimensional finite element analyses of the model used by Gebhardt and Pauwels. We demonstrate that Pauwels's photoelastic results are correct but are based on the imposition of incorrect boundary conditions. When more realistic boundary conditions were used, the finite element results changed dramatically. These results suggest that (a) the ossific nucleus appears in an area of high shear (deviatoric) stresses; (b) the edge of the advancing ossification front (zone of Ranvier or ossification grove) also experiences high shear stresses; and (c) the joint surface, where articular cartilage forms, is exposed to high‐magnitude hydrostatic compression. These findings support the theory proposed by Carter and associates that intermittently applied shear stresses (or strain energy) promote endochondral ossification and that intermittently applied hydrostatic compression inhibits or prevents cartilage degeneration and ossific

ISSN:0736-0266    

DOI:10.1002/jor.1100060120

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

ISSN:0736-0266    

DOI:10.1002/jor.1100060101

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY