bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microscopical investigation of canine anterior cruciate ligament and patellar tendon: Collagen fascicle morphology and architecture
Authors: Yahia L.‐H. , Drouin G. 
Published: February 2005

AbstractThe collagen structure of the canine anterior cruciate ligament (ACL) and patellar tendon (PT) was examined by using light and scanning electron microscopy. The collagen waviness known as a crimping was found to occur in ACL and PT fascicles. This waviness, seen at the periphery of fascicles, is very smooth, and its amplitude seems to decrease from the periphery toward the fascicular center. It appears as a periodic collapse of the fascicle in two dimensions. Two models of the architectural patterns of the ACL and PT wavy fascicles are presented. The constituent collagen fibrils are either parallel or twisted relative to the fascicle axis, giving rise to planar and helical wave patterns, respectively. There is a distinct difference between the ACL and PT collagen structure. The helical wave pattern occurs in both PT and ACL while the planar waveform is found only in the centrally located ACL fascicles. In addition, there is less variability in fascicular size and density over the PT cross‐section than in ACL.
Contact pressures in the patellofemoral joint during impact loading on the human flexed knee
Authors: Haut Roger C. 
Published: February 2005

AbstractCurrently, a bone fracture criterion is used by the automotive industry to assess the potential for a lower extremity injury from impact directed on the flexed knee. However, recent studies with animal models indicate irreversible damage to articular cartilage due to overpressures generated within the patellofemoral (P‐F) joint without bone fracture, and suggest this injury may lead to a progressive, degenerative disease of the joint. The purpose of this investigation was to measure contact pressure in the human P‐F joint during impact loading on the isolated, flexed knee. Loads were delivered on the patella with a free‐flight inertial mass that had a rigid or foam padded interface. The experiments were conducted by serially increasing the impactor velocity in repeated tests until bone fracture was observed. The distribution of maximum pressures generated within the joint was recorded with a pressuresensitive film. Fracture of the patella or the femur occurred at impact loads of approximately 8.5 kN. The average P–F pressure was approximately 25 MPa for 8 kN of impact load on the 90° flexed joint. The P–F contact area varied with the level of contact load and degree of joint flexion. The distribution of P–F pressures was nonuniform. At approximately 70% of the fracture load for the 90° flexed knee, nearly 35% of the contact area was exposed to pressures greater than 25 MPa. In an earlier study by others using subchondral bonecartilage preparations, this level of pressure resulted in fissures and lacerations of the cartilage.
Effect of denervation on limb growth
Authors: Dietze Frederick R. 
Published: February 2005

AbstractThis study used Rana pipiens tadpoles to assess the effect of complete and partial sciatic denervation on tibial bone growth and foot growth. Complete sciatic denervation was performed in R. pipiens at Stages XIV, XVII, and XX and they were killed at Stages XVII, XX, and XXIV. Partial denervation consisted of peroneal or tibial nerve sectioning at Stages XVII and XX with killing at Stages XX and XXIV. Analysis of experimental animals and controls consisted of (a) quantitative axon counts, (b) tibial length, (c) midtibial cross‐sectional area, (d) midtibial cortical thickness, (e) midtibial cartilage anlage cross‐sectional area, (f) foot silhouette area, and (g) osteocyte number and osteocyte density. Both complete and partial denervation resulted in significant effects on bone and foot growth: (a) decreased bone length, (b) decreased cross‐sectional bone area without cortical thinning, (c) increased cartilage anlage cross‐sectional area, and (d) decreased foot size. This experiment demonstrated a trophic effect of nerve on bone growth and development and foot growth. The mechanism of this action is unknown but the data suggests a slowed rate of maturation in denervated bones. The possibility exists that defective peripheral nerve–limb tissue interactions may cause human deformities such as idiopathic clubfoot and idiopathic limb length discrepancy.
Frequency spectrum analysis of wrist motion for activities of daily living
Authors: Mann Kenneth A. , Wernere Frederick W. , Palmer Andrew K. 
Published: February 2005

AbstractA frequency spectral analysis was performed on wrist motion data for 24 activities of daily living (ADLs). Wrist motion was measured using a triaxial electrogoniometer attached to the wrist using tape (for 12 subjects) and pins (for one subject). Results show that the average predominant frequency component of these ADLs was ∼ 1 Hz with 75% of the spectral energy <5 Hz. The taped‐on electrogoniometer, when compared with the pinned electrogoniometer, was adequate for calculating the predominant frequency componenet and spread of spectral data, but overestimated the magnitudes of the maximum spectral density and total area of the spectral curves. This discrepancy was largest for axial rotation.
Cobalt, chromium, and nickel concentrations in body fluids of patients with porous‐coated knee or hip prostheses
Authors: Sunderman F. William , Hopfer Sidney M. , Swift Thomas , Rezuke William N. , Ziebka Linda , Highman Paul , Edwards Brian , Folcik Marilyn , Gossling Harry R. 
Published: February 2005

AbstractCo, Cr, and Ni concentrations were determined by electrothermal atomic absorption spectrophotometry in serum and urine specimens collected from a group of 28 patients at intervals of from 1 day to 2.5 years after total knee or hip arthroplasty with porous‐coated prostheses fabricated of Co‐Cr alloy (ASTM F‐75‐82). Two control groups were also tested: (a) 42 healthy adults and (b) 16 orthopaedic patients after total knee or hip arthroplasty with porous‐coated prostheses fabricated predominantly of Ti‐Al‐V alloy (ASTM F‐136‐84). All prostheses contained polyethylene components to avoid metal‐to‐metal contact. Mean Co concentrations in serum and urine were slightly increased in patients with Co‐Cr knee implants at 6–120 weeks after surgery, compared with (a) preoperative values, (b) corresponding values in patients with Co‐Cr hip implants, and (c) corresponding values in control patients with Ti‐Al‐V knee and hip prostheses. Substantially increased Co levels were observed in serum and urine of two patients at 7 weeks and 22 months postarthroplasty, associated with loosening of the prostheses; one of the patients also had elevated Cr levels in serum and urine. Although ASTM F‐75‐82 and F‐136‐84 alloys contain very little Ni (<1.0 and <0.2% Ni, respectively, by wt), mean Ni concentrations in serum and urine were greatly increased at 1–2 days after implantation of Ti‐Al‐V and Co‐Cr prostheses, diminishing by 2 weeks. The postoperative hypernickelemia and nickeluresis may reflect contamination of the operative field with Ni‐containing particles from the drills, cutting jigs, and drilling jigs, or it may represent a previously unrecognized pathophysiological response to surgery.
Intramedullary bone repair and ingrowth into porous coated implants in the adult chicken: A histologic study and biochemical analysis of collagens
Authors: Brown Cameron C. , McLaughlin Robert E. , Balian Gary 
Published: February 2005

AbstractA new model was developed to study the histologic and biochemical events during intramedullary bone repair and ingrowth into porous coated implants. Adult chickens were used because of the availability of specific antibody probes. Repair in the metaphysis and diaphysis were compared. Entering through a medial arthrotomy, the distal tibiotarsus was reamed and either impianted with a double‐ended porous coated rod or allowed to heal without implantation of a rod. Specimens analyzed histologically at 7, 14, 21, and 70 days postoperatively revealed direct formation of bone by osteoblasts with no evidence of a cartilaginous phase. At 70 days bony ingrowth was observed deep within the porous surface. Analysis of collagens with sodium dodecyl sulfate polyacrylamide gel electrophoresis demonstrated that the synthesis of type I collagen predominated. Biosynthetic data coupled with quantitative immunologic analyses using antibodies to type II and type X collagen showed that neither of these two collagen types, which are characteristic of cartilage undergoing endochondral ossification, were produced during intramedullary bone repair. These results establish that the adult chicken is capable of bony ingrowth into porous coated implants and that this process is through direct bone deposition by osteoblasts without a cartilaginous intermediate.
Cryopreserved articular chondrocytes grow in culture, maintain cartilage phenotype, and synthesize matrix components
Authors: Schachar N. , Nagao M. , Matsuyama T. , McAllister D. , Ishii S. 
Published: February 2005

AbstractFor osteochondral allograft transplantation to be successful, chondrocytes must survive preservation and retain their capacity to produce normal matrix components: proteoglycans and Type II collagen. Clinical success with osteochondral allograft transplantation has created an increased demand for supplies of suitable cartilage‐bearing grafts. This demand has stimulated attempts to find successful methods for low temperature storage of cartilage for “banking” and heightened interest in cartilage cryobiology. In order to achieve the maximum viability of cryopreserved articular cartilage, previous comprehensive studies have focused on rates and temperatures of freezing, cryoprotective agents, and methods and influences of thawing. This study presents evidence that cryopreserved articular chondrocytes maintain their ability to grow in tissue culture following thawing and to produce normal matrix components. Chondrocytes isolated from Japanese white rabbits were divided into groups of fresh controls and experimental cryopreserved cells. Cells were incubated in dimethylsulfoxide, frozen at a rate of −1°C/min, stored at −79°C, rapidly thawed, and plated for culture, Growth rates were comparable in all groups. In all groups, typical chondroid characteristics were maintained throughout 14 days of culture. Typical cartilage phenotypic characteristics included maintenance of polygonal and rhomboidal cells, cell aggregation, proteoglycan production, and Type II collagen synthesis. This investigation strongly indicates that articular chondrocyte cryopreservation yields viable, functional cells and although these results cannot be directly extrapolated to intact adult articular cartilage, they do give further support for low temperature banking of cartilage‐bearing allografts for transplantation.
Loads on the lumbar trunk during level walking
Authors: Cromwell Ronita , Schultz Albert B. , Beck Robert , Warwick David 
Published: February 2005

AbstractThe goal of this study was to estimate the loads internal to the lumbar trunk that arise during level walking. To do this, (a) trunk muscle activities were calibrated in terms of muscle contraction force levels in a set of isometric exertions; (b) trunk muscle myoelectric activities were measured during level walking; and then (c) the muscle contraction forces that arose during walking were calculated from these measurements and calibrations. Lumbar trunk muscle myoelectric activities were quantified in 10 healthy young males. Myoelectric activities were monitored using eight bipolar surface electrode pairs placed around the trunk at the level of the third lumbar vertebrae. The subjects first performed four static weight‐resisting tasks to calibrate muscle force/activity relationships. They then traversed a 8.25 m walkway three times each at cadences of 72 and 120 steps/min. A biomechanical model incorporating 22 lumbar trunk muscles was used to predict muscle contraction forces for the calibration tasks. Predicted forces were linearly correlated with the measured myoelectric activities for these tasks. The regression equations were then interpolated to estimate the muscle contraction forces from the myoelectric data during gait. Peak contraction forces for the iliocostalis muscles were calculated to be approximately 55 N per side, corresponding to total erector spinae peak contractions on the order of 140 N per side. For the other six muscles that were monitored, contraction forces were less than 15 N per side. This suggests that peak net reaction moments and peak spine compressions on the lumbar trunk during these walking tasks were on the order of 15 Nm and 1.2 times body weight, respectively.
The effect of grip strength on radial bone in postmenopausal women
Authors: Sandler Rivka Black , Cauley Jane A. , Sashin Donald , Scialabba Mary Ann , Kriska Andrea M. 
Published: February 2005

AbstractThis communication explores the correlation in 255 postmenopausal women of grip strength to bone tissue density (BTD) and cross‐sectional area (CSArea) of the radius. While grip strength correlated cross‐sectionally with the baseline measures of both BTD and CSArea, grip strength affected differentially the changes that transpired in the two bone parameters over the 3 years of the study. Thus, the increases in the CSArea of the radius were significantly enhanced by higher grip strength, while BTD losses were not. Since the power of muscle contraction is a factor in the mechanical loading of a bone, it is argued that the differential effects of grip strength on the two bone parameters of the radius suggest that moderate loading can effect favorable changes in the geometry of the bone, without necessarily affecting changes in BTD.
Gowth factor production by sarcoma cells in primary culture
Authors: Bell R. S. , Bell D. F. , Jacob J. , Trippel S. , Gebhardt M. C. , Mankin H. J. 
Published: February 2005

AbstractCell lines derived from human sarcomas have been previously shown to produce a protein growth factor which, similar to platelet‐derived growth factor (PDGF), can induce competence for mitosis in fibroblasts. Whether this factor production is an important feature of sarcomas in vivo or simply an artefact caused by long‐term culture conditions is unclear, however. We demonstrated growth factor activity in conditioned medium from six of 11 primary sarcoma cultures, utilizing flow cytometric analysis of DNA to monitor the presence of sarcoma cells in cultures. Cells isolated from control tissues failed to show a similar mitotic effect.
Injury of the anterior cruciate ligament: The role of collagenase in ligament degeneration
Authors: Amiel D. , Ishizue K. K. , Harwood F. L. , Kitabayashi L. , Akeson W. H. 
Published: February 2005

AbstractRapid degeneration of the anterior cruciate ligament (ACL) has been observed following acute ACL rupture. An understanding of this process might explain some of the poor clinical results of primary ACL repair. We created a surgical rabbit model of acute ACL injury and developed an in vitro assay for collagenase activity in the ACL and menisci. Microscopic evaluation revealed a rapidly degenerative process in injured ACLs, with loss of cellularity and matrix organization. This was associated with a significant increase in collagenase activity and a decrease in total collagen of the injured ACLs as compared with sham‐operated controls. These findings confirm the observation that cut ACL ligament ends rapidly degenerate. This degenerative process might be partly due to a response of cells intrinsic to the ACL to injury. Left unchecked, this process may be detrimental to surgical attempts for primary ACL repair.
The effect of cryopreservation on the biomechanical behavior of bovine articular cartilage
Authors: Kiefer G. N. , Sundby K. , McAllister D. , Shrive N. G. , Frank C. B. , Lam T. , Schachar N. S. 
Published: February 2005

AbstractThe short‐term effect of cryopreservation on specific mechanical behaviors of bovine articular cartilage has been investigated. A flat‐ended nonporous indentor was used in a nondestructive, repetitive, axisymmetric unconstrained testing system. Cyclical indentation from a fixed position to a fixed load was applied until a steady‐state load‐deformation relationship (limit cycle) was achieved. Indentation behaviors measured from the limit cycles of each articular cartilage specimen before and after treatment were compared. Testing was done in vitro using fresh, mature bovine radiocarpal joints. Twenty pairs of cartilage‐subchondral bone cores from anatomically similar sites on contralateral joints were separated into three groups; thickness controls, dimethylsulfoxide (DMSO) controls, and cryopreserved experimental samples. Thickness controls and DMSO controls were used to examine the isolated effects of the thickness measurement and DMSO incubation techniques on articular cartilage indentation characteristics. Experimental samples were cryopreserved using DMSO, their thicknesses similarly measured and indentation behaviors examined. Following testing, histological and histochemical assessment of the specimens confirmed the nondestructive nature of the tests. Intra‐ and intergroup comparisons of controls and experimentals revealed no statistical differences in the mechanical behaviors measured from the limit cycle or in cartilage thickness. These results indicate that the cryopreservation protocol used did not have an effect that we could measure on these specific mechanical behaviors of articular cartilage.
Effects of electrical stimulation on joint contracture in a rat model
Authors: Tart Roger P. , Dahners Laurence E. 
Published: February 2005

AbstractThis study was intended to delineate whether electrical stimulation could significantly reduce the amount of joint contracture in a rat model. Rat knees were surgically immobilized in 150° of flexion. Two groups of rats had sham electrodes, and two groups were electrically stimulated. All rats were killed 14 days after surgery. The degree of joint contracture was assessed by measuring the femorotibial angles with a 0.015‐Nm extension moment applied. When the electrical current was applied in a transverse manner, there was a statistically significant reduction in the amount of posterior capsule (p < 0.005) and anterior cruciate ligament (ACL) (p < 0.005) contracture. When the electrical current was applied longitudinally, no significant difference in the amount of joint contracture was found. These findings support the hypothesis that electrical stimulation can inhibit joint contracture. These findings also suggest that the effect occurs when the electrical current is applied transversoly as opposed to longitudinally.
Different effects of mechanical vibration on bone ingrowth into porous hydroxyapatite and fracture healing in a rabbit model
Authors: Usui Yasuo , Zerwekh Joseph E. , Vanharanta Heikki , Ashman Richard B. , Mooney Vert 
Published: February 2005

AbstractThe effects of mechanical vibration on bone ingrowth into porous hydroxyapatite implants and fracture healing were examined radiographically, histomorphometrically, and biomechanically in a rabbit model. Fifty‐three female NZW rabbits were used in this study. These rabbits were divided into four separate studies to assess the effects of 20 and 60 min of vibration/day in both implant and osteotomy models as compared with the respective nonvibrated controls. For the implant model, coral hydroxyapatite goniopora rods were implanted bilaterally into tibiae and for the osteotomy model, bilateral fibulae were osteotomized. A resonant frequency of 25 Hz mechanical vibration was used. After periods of 2, 3, 4, and 6 weeks of vibration, the rabbits were killed and examined. For the implant model, there was no significant difference between control, 20, or 60 min of vibration/day with respect to the rate or amount of new bone ingrowth. For the fracture model, 60 min of vibration/day produced a significantly larger callus as compared with the nonvibrated controls (p < 0.05), whereas 20 min of vibration/day did not. Although biomechanical testing demonstrated a general trend for increased strength in the vibrated animals, it failed to reach significance. These results suggest that the mechanical vibration used in the present study had a beneficial effect on callus volume, possibly due to the stimulation of secondary bone healing processes, but does not appear to promote bone ingrowth into a porous hydroxyapatite implant.
Allograft incorporation: A biomechanical evaluation in a rat model
Authors: Pelker Richard R. , McKay James , Troiano Nancy , Panjabi Manohar M. , Friedlaender Gary E. 
Published: February 2005

AbstractAllogeneic bone from Sprague‐Dawley rat femurs was subjected to levels of freezing and/or irradiation that are known to have produced changes in the associated immune responses to these grafts. This bone was transplanted into an experimentally created gap in the femur of Lewis rats. The subsequent healing of the transplants in the Lewis rats was studied at 2,4,8, and 16 weeks after transplantation using torsion testing to failure. There was no clear advantageous biologic response in the union of the grafted material accompanying the alterations in immunologic response as measured by biomechanical testing of the proximal osteosynthesis site in torsion. The torsional strength of all of these groups remained lower than that of intact bone. Furthermore, none of the frozen and/or irradiated allografts exceeded the strength of the fresh allograft at a statistically significant level.
Rib cage asymmetry in idiopathic scoliosis
Authors: Stokes Ian A. F. , Dansereau Jean , Moreland Morey S. 
Published: February 2005

AbstractSeventy‐one patients attending a scoliosis clinic and 10 control subjects were studied by a stereoradiographic three‐dimensional reconstruction of the spine and rib cage. The symmetry of each rib pair (at each anatomic level) was described by measurements of rib arc length, chord length, enclosed area, maximum curvature, and frontal and lateral angulations. Patients were divided into four groups: 19 with a single right thoracic curve, 15 with a single left lumbar or thoracolumbar curve, 22 with double curves, and 15 with a curve with 10° Cobb angle. In the control group and the group with minimal scoliosis, there was no statistically significant rib asymmetry. Among the patients with scoliosis, 11 of 19 patients with right single thoracic curves had rib arc lengths greater on the right side at the curve apex, and nine of 15 patients with left lumbar scoliosis had longer ribs on the left side in the corresponding region of the thoracic spine. Eleven of 22 patients with double curves had symmetrical rib lengths (within ∼3%), the other 11 had ribs longer on the left. These proportions should not have occurred by chance (p < 0.001). The mean rib length difference in patients with single thoracic curves was 1.39% (right longer than left), in single lumbar curves it was 3.57% (left longer than right), and in double curves 3.18% (left longer than right). These differences between the groups of patients and control subjects were statistically significant (p < 0.01). Based on correlations between rib arc length and other measurements of rib size, there was evidence of general rib hypertrophy on the long rib side of patients having length asymmetries.