bluuebunny/crossref_metadata_2025_split huggingface dataset:
The dermatan sulfate proteoglycans of the adult human meniscus
Authors: Roughley Peter J. , White Robert J. 
Published: February 2005

AbstractThe dermatan sulfate proteoglycans decorin and biglycan were extracted from pooled adult human menisci with 4 M guanidinium chloride and purified by successive cesium chloride density gradient centrifugation, ion exchange chromatography, and gel filtration. A final yield of about 2 mg of dermatan sulfate proteoglycan per gram of wet tissue was obtained. The proteoglycan is predominantly decorin with some biglycan, and the dermatan sulfate chains contain about 70% of their uronic acid residues as iduronate and possess about three times as much 4‐sulfation as 6‐sulfation of their N‐acetylgalactosamine residues. On gel filtration under associative conditions, about half of the proteoglycan exhibits self‐association. This includes most of the biglycan but also a substantial proportion of decorin. The molecules that show self‐association appear to have longer dermatan sulfate chains, though there is no apparent difference in their overall composition. The predominance of decorin in the adult meniscus and its ability to interact both with itself and collagen fibrils is compatible with a role in maintaining tissue integrity and strength.
The functional recovery of peripheral nerves following defined acute crush injuries
Authors: Chen Long‐En , Seaber Anthony V. , Glisson Richard R. , Davies Helen , Murrell George A. C. , Anthony Douglas C. , Urbaniak James R. 
Published: February 2005

AbstractThis study evaluates the effect of crushing load on functional recovery of the sciatic nerve. Male Sprague‐Dawley rats were divided into five groups: sham operation, resected sciatic nerve, and 100 g (13 mm Hg/mm2), 500 g (50 mm Hg/mm2), and 15,000 g (1,000 mm Hg/mm2) of sciatic crush load (groups 1–5). In groups 3–5, a 5‐mm segment of sciatic nerve was crushed for 10 min using a specially designed crushing device. Motor functional recovery was assessed from hind‐limb walking tracks by calculating a sciatic functional index. There was no detectable functional deficit in the group receiving sham operations, while the resected sciatic nerve group exhibited complete dysfunction for the full duration of the experiment. All groups subjected to crush exhibited an initial deficit that gradually recovered to normal by day 14 (100‐g crush), day 39 (500‐g crush), and day 53 (15,000‐g crush). Histological changes were also related to the initial crushing load and the length of the recovery period. Results indicate that the crushing device described is able to administer an adjustable, defined crush injury to the rat sciatic nerve, and that the functional deficit resulting from such an injury can be easily monitored with a sciatic functional index. The rate of recovery of crushed nerves was directly related to the initial load. All crushed nerves recovered in this experiment, even after the application of a 15,000‐g load for 10 min.
A longitudinal study of the matrix changes induced in the intervertebral disc by surgical damage to the annulus fibrosus
Authors: Melrose J. , Ghosh P. , Taylor T. K. F. , Hall A. , Osti O. L. , Vernon‐Roberts B. , Fraser R. D. 
Published: February 2005

AbstractA 5 × 5‐mm anterolateral incision was made in the annulus fibrosus (AF) of lumbar discs of 16 sheep; four animals of similar age not operated on were used as controls. The experimental animals were sacrificed 2, 4, 6, 8, 12, and 18 months postoperatively (PO), and the incised and adjacent lumbar discs were collected. Discs were dissected into four zones: AF (zones 1 and 2) and nucleus pulposus (NP) (zones 3 and 4) corresponding to the half of the AF in which the cut was made and its opposite half, and the complementary halves of the NP. Each zone was analyzed for moisture, proteoglycan (PG), collagen, and noncollagenous protein (NCP) content. The PG extractability, aggregation, and hydrodynamic size were also examined. The NP of injured discs showed a significant loss of PGs and collagen 8 months PO, but NCP levels increased. In the incised discs, PG aggregation initially declined but recovered to within control values 6–8 months PO. The NP of discs adjacent to the incised disc also showed time‐dependent changes in matrix components that included loss of collagen and PG; however, the AF matrix remained essentially uneffected. Double immunodiffusion studies indicated that a sizeable proportion of the NCPs present in the injured discs (but not the adjacent lumbar discs) were derived from serum.
Trunk muscle cocontraction: The effects of moment direction and moment magnitude
Authors: Lavender S. A. , Tsuang Y. H. , Andersson G. B. J. , Hafezi A. , Shin C. C. 
Published: February 2005

AbstractThis study investigated the cocontraction of eight trunk muscles during the application of asymmetric loads to the torso. External moments of 10, 20, 30, 40, and 50 Nm were applied to the torso via a harness system. The direction of the applied moment was varied by 30° increments to the subjects' right side between the sagittally symmetric orientations front and rear. Electromyographic (EMG) data from the left and right latissimus dorsi, erector spinae, external oblique, and rectus abdominus were collected from 10 subjects. The normalized EMG data were tested using multivariate and univariate analyses of variance procedures. These analyses showed significant interactions between the moment magnitude and the moment direction for seven of the eight muscles. Most of the interactions could be characterized as due to changes in muscle recruitment with changes in the direction of the external moment. Analysis of the relative activation levels, which were computed for each combination of moment magnitude and direction, indicated large changes in muscle recruitment due to asymmetry, but only small adjustments in the relative activation levels due to increased moment magnitude.
Cross talk in surface electromyograms of human hamstring muscles
Authors: Koh Timothy J. , Grabiner Mark D. 
Published: February 2005

AbstractSignals generated from muscles other than the muscle(s) of interest (cross talk) can confound the interpretation of surface electromyograms (EMGs). In this study, the amount of cross talk in surface EMGs of human hamstring muscles was estimated using a protocol in which the quadriceps femoris was electrically stimulated via the femoral nerve. EMGs were recorded from the vastus lateralis and the medial and lateral hamstring muscle groups. The amplitude of the EMG response of the vastus lateralis to electrical stimulation was adjusted to match that of its maximum voluntary effort (MVE) under isometric conditions. Subsequent power density spectrum analysis showed that the median frequencies of the signals generated by electrical stimulation and MVE were not significantly different. In conventional bipolar recordings, cross talk in lateral hamstring EMGs averaged 17.1% MVE and in medial hamstring EMGs 11.3% MVE (average‐rectified values). The double differential technique significantly reduced cross talk to 7.6% MVE for the lateral hamstrings, and to 4.2% MVE for the medial hamstrings. The double differential technique appears to be more selective than the bipolar technique when recording EMGs from muscles with highly active neighbors and thus should be used in such situations. Software simulations of the double differential technique also appear to be more selective than the bipolar technique and may be used when the number of amplifiers available is limited.
A comparison of cortical strain after cemented and press‐fit proximal and distal femoral replacement
Authors: Hua J. , Walker P. S. 
Published: February 2005

AbstractProximal and distal femoral replacements with intramedullary stems are usually cemented in place but frequently show severe bone remodeling changes in the long term, which can contribute to a loosening process. The remodeling is likely to be associated with stress and strain distribution. This study compared the strain patterns, particularly the maximum principal strains, between cemented and press‐fit components in five cadaveric femurs by using a photoelastic coating technique. The specimens were loaded with 2,000 N in the sequences of intact femur and press‐fit and cemented stems. On the medial side of the bone for proximal femoral replacements, the strain values for the press‐fit stems on the proximal, middle, and distal regions were 73 ± 11%, 78 ± 15%, and 80 ± 15% of normal, respectively, but for the cemented stems they were 53 ± 15%, 57 ± 19%, and 60 ± 20%. The differences were statistically significant (p < 0.05). On the lateral side, the overall strain values for the press‐fit stem were higher than those for the cemented stem, but the differences were not statistically significant (p > 0.05). On the medial side of the distal femoral replacement, the strain values for the press‐fit stems in the proximal and middle regions were significantly closer to normal than for the cemented stems. Because the press‐fit femoral stems (both the proximal and distal replacement) transferred closer to normal strains than the cemented stems, less adverse bone remodeling may be expected, which could be reflected in increased longevity.
Subchondral damage after acute transarticular loading: An in vitro model of joint injury
Authors: Vener Michael J. , Thompson Roby C. , Lewis Jr. Jack L. , Oegema Theodore R. 
Published: February 2005

AbstractIntact canine metacarpophalangeal and metatarsophalangeal joints were subjected to a variety of loads in vitro. Intraarticular fracture occurred in 19 joints loaded to an average force of 2.4 ± 0.4 kN with a corresponding loading rate of 88 ± 23 kN/s. The remaining 29 joints were without gross evidence of fracture with an average load and loading rate of 1.7 ± 0.9 kN and 64 ± 32 kN/s, respectively. In the fractured specimens, damage to the zone of calcified cartilage and subchondral bone was much more extensive than was initially evident by gross inspection when assessed by scanning electron microscopy. Cracks with associated step‐off displacement at the zone of calcified cartilage were found distant to the gross fractures. These findings were confirmed histologically. In addition, cracks localized to the zone of calcified cartilage were commonly identified histologically in specimens loaded in the range of 1.9–2.8 kN, but were not grossly fractured. The contact area determined with pressure‐sensitive film increased with increasing load up to the point of fracture. The average pressure generated at the articular cartilage surface at the time of fracture in this model is ≥40 MPa, and the fracture occurred at the contact site. Our findings suggest that failure in acute transarticular loading begins in the zone of calcified cartilage and subsequently involves the subchondral bone and overlying cartilage. This type of injury may contribute to the development of osteoarthritis after intraarticular fracture, or at high loads that do not result in gross fracture.
Identification of integrin cell‐substratum adhesion receptors on cultured rat bone cells
Authors: Brighton Carl T. , Albelda Steven M. 
Published: February 2005

AbstractThe interactions of bone cells with their extracellular matrix is of major importance in bone development, repair, and disease. We examined the ability of rat calvarial bone cells to adhere to various matrix proteins and to define the role of integrin cell‐substrate adhesion receptors in these interactions. Isolated newborn rat calvarial bone cells prelabeled with3H‐thymidine and plated on plastic wells that had been precoated with serial dilutions of various substrates showed typical dose‐response adherence curves to fibronectin, fibrinogen, laminin, vitronectin, and collagen I and IV. Cell adherence to poly‐D‐lysine, a nonspecific cell adherent, was high at all substrate concentrations >0.0001 μg/ml. A polyclonal anti‐rat integrin antibody blocked cell adhesion to all substrates tested except poly‐D‐lysine. Isolated rat calvarial bone cells were surface labeled with125I, extracted, and immunoprecipitated with polyclonal antibodies made against the rat integrin complex and peptides derived from the cytoplasmic domains of the α2, α3, and α5subunits. Analysis by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (nonreduced) identified four bands representing a mixture of integrins including the α1β1laminin/collagen receptor, the α5β1fibronectin receptor, and the αvβ3(or possibly αvβ5) vitronectin receptor. These experiments show that bone cells adhere to a wide variety of extracellular matrix proteins via specific integrins. Increased knowledge about the regulation of these receptors and the mechanisms by which they transmit information to the cell will be important for a more complete understanding of bone physiology and pathophysiology.
Cast immobilization and tibial diaphyseal blood flow: An initial study
Authors: Triffitt Paul D. , Cieslak Catharine A. , Gregg Paul J. 
Published: February 2005

AbstractThe effect of cast immobilization on blood flow to the tibial diaphysis was studied by the microsphere method, both before and after casting of one hindlimb of adult New Zealand White rabbits. Preliminary studies were undertaken to investigate the possibility of the reduction of tibial flow by the microspheres used for the control measurements of blood flow. There were no significant differences in the flows to the tibial diaphysis or skeletal muscle between the immobilized and control limbs after either 1 or 2 weeks. This similarity between control and experimental limbs indicates that immobilization had no major effect on tibial blood flow over and above the systemic effects of the procedure.
Acute effect of traction, compression, and hip joint tamponade on blood flow of the femoral head: An experimental model
Authors: Naito Masatoshi , Owen Jeffrey H. , Schoenecker Perry L. , Sugioka Yoichi 
Published: February 2005

AbstractBlood flow rates of the canine femoral head were experimentally determined during traction, compression, and hip joint tamponade using the hydrogen washout technique. In puppies, blood flow rate of the femoral head was significantly decreased with either traction or compression applied at one half body weight. Either maneuver, when combined with hip joint tamponade, reduced blood flow rate of the femoral head an average of more than 70% as compared with the initial control rate. In adult dogs, combinations of either traction or compression, at one‐half body weight, with hip joint tamponade did not significantly decrease blood flow rate of the femoral head as compared with control values. Perfusion defect of blue silicone could be observed only in puppies around the hip during combinations of traction or compression with hip joint tamponade and involved the posterior superior capital branches of the medial circumflex artery and the arteries in the ligamentum teres. These experimental data may have important implications for the pathogenesis of iatrogenic avascular necrosis in the treatment of congenitally dislocated hip, Legg‐Perthes disease, and avascular necrosis following nondisplaced femoral neck fracture.
A theory of fatigue damage accumulation and repair in cortical bone
Authors: Martin Bruce 
Published: February 2005

AbstractAn analysis is presented of the balance between the accumulation and repair of fatigue damage in osteonal bone. Fatigue damage is defined in terms of cracks seen histologically when precautions are taken to avoid preparation artifact. The rate of occurrence of such damage is assumed to be proportional to the product of applied peak‐to‐peak stress, raised to a power, and the loading frequency. The rate of damage repair is assumed to be proportional to the activation rate for osteonal remodeling, and to the mean cross‐sectional area of the resulting osteons. An additional factor is introduced to account for the possibility that damage provokes nearby remodeling. The theory is used to compare data from previous experiments of two types: fatigue‐to‐failure, and studies in which histologically observable cracks are made more numerous by repetitive loading. The analysis shows that there is a measure of agreement between the results of the two kinds of experiments, but the current data are too limited, and the results are too dependent on the mode of loading, to adequately test the theory. However, the analysis provides a framework for designing experiments to more efficiently clarify the relationships between fatigue failure, cracks seen in histologic sections, and the rate at which such cracks are repaired by osteonal remodeling.
Migration of porous coated acetabular prostheses fixed with screws: Roentgen stereophotogrammetric analysis
Authors: Kärrholm Johan , Snorrason Finnur 
Published: February 2005

AbstractThe fixation of screw‐fixed, porous‐coated acetabular prostheses was studied during 2 years in 21 patients (22 hips) using repeated roentgen stereophotogrammetric measurements. Migration of the center of the prostheses and/or tilting were recorded in five cups after 6 months. Two years after operation, migration was recorded in three, migration and rotation in six, and only rotation in three cups. Bone quality, prosthetic position, and immediate postoperative radiographic appearance of the prosthesis‐bone interface did not correlate with the occurrence of migration. Narrow radiolucent zones had developed in half of the patients after 2 years and was associated with proximal migration. Micromovements of screw‐fixed, press‐fit cups seem to start later compared with previously presented results from cemented acetabular prosthesis.
In vitro hyperextension injuries in the human cadaveric cervical spine
Authors: Shea M. , Wittenberg R. H. , Edwards W. T. , White A. A. , Hayes W. C. 
Published: February 2005

AbstractTo investigate the relationship between the type of hyperextension injuries and the conditions producing them, nine cervical specimens (occiput to T1) were loaded to failure in tension at a fixed extension angle of 30°. Under these loading conditions, specimens failed at average tensile loads and extension moments of 499 ± 148 (SD) N and 4.0 ± 3.1 Nm, respectively. Failure occurred at an average tensile displacement of 18.8 ± 7.7 mm. The anterior longitudinal ligament reptured and the intervertebral disc failed in at least one level in all specimens. In four specimens, the disc failed at an additional level, leaving the anterior longitudinal ligament intact at that site. With one exception, all injuries occurred in the lower cervical spine (C5‐C6 and C6‐C7), the region most often injured in vivo. The location of the injuries was associated with the degree of degeneration of the facet joints and the discs. The discs of the lower cervical spine were significantly more degenerated than those at the C2‐C3 level. In addition, the degree of disc degeneration in the noninjured discs was significantly less than in the injured discs. These data help quantify the threshold of injury and the patterns of tissue damage resulting from hyperextension loading of the cervical spine.
Physiological cross‐sectional area of human leg muscles based on magnetic resonance imaging
Authors: Fukunaga T. , Roy R. R. , Shellock F. G. , Hodgson J. A. , Day M. K. , Lee P. L. , Kwong‐Fu H. , Edgerton V. R. 
Published: February 2005

AbstractMagnetic resonance imaging techniques were used to determine the physiological cross‐sectional areas (PCSAs) of the major muscles or muscle groups of the lower leg. For 12 healthy subjects, the boundaries of each muscle or muscle group were digitized from images taken at 1‐cm intervals along the length of the leg. Muscle volumes were calculated from the summation of each anatomical CSA (ACSA) and the distance between each section. Muscle length was determined as the distance between the most proximal and distal images in which the muscle was visible. The PCSA of each muscle was calculated as muscle volume times the cosine of the angle of fiber pinnation divided by fiber length, where published fiber length:muscle length ratios were used to estimate fiber lengths. The mean volumes of the major plantarflexors were 489, 245, and 140 cm3 for the soleus and medial (MG) and lateral (LG) heads of the gastrocnemius. The mean PCSA of the soleus was 230 cm2, about three and eight times larger than the MG (68 cm2) and LG (28 cm2), respectively. These PCSA values were eight (soleus), four (MG), and three (LG) times larger than their respective maximum ACSA. The major dorsiflexor, the tibialis anterior (TA), had a muscle volume of 143 cm2, a PCSA of 19 cm2, and an ACSA of 9 cm2. With the exception of the soleus, the mean fiber length of all subjects was closely related to muscle volume across muscles. The soleus fibers were unusually short relative to the muscle volume, thus potentiating its force potential. Using the relationship between PCSA and fiber length to represent the maximum force‐velocity potential of a muscle and assuming a similar moment arm, the soleus, MG, and LG would be expected to produce ±71, 22, and 7% of the force and 54, 30, and 16% of the power of the major plantarflexors. These data illustrate some of the major limitations in the use of ACSA measurements to predict the functional properties of a muscle.
Evaluation of a local microsphere injection method for measurement of blood flow in the rabbit lower extremity
Authors: Maki Yutaka , Breidenbach Warren C. , Firrell John C. 
Published: February 2005

AbstractThe precision of a modified microsphere technique to measure blood flow in the hind limb of the rabbit was determined. Regional (local) injections made via a catheter in the aorta and blood withdrawn through a catheter in the hind limb enabled deposition of a high concentration of microspheres in the tissues while minimizing the number of microspheres needed for accurate measurement. 95Niobium and 141cerium‐labeled 16 μm diameter microspheres were used. Blood flow was measured in 15 locations of muscle and skin for simultaneous injections into the aorta and left ventricle (group A), simultaneous injections of a mixture into the left ventricle (group B), and ventricular injections given 1 h apart (group C). No significant differences in mean blood flow measurements were found. Correlation coefficients between local and ventricular injections ranged from 0.89–0.99 and between 0.994 and 0.999 for two simultaneous ventricular injections. The variability over time was greater, with correlations between the first and second injections ranging from 0.13–0.939. Precision of the local technique compared with the ventricular technique can be kept within 30% with five or six animals. The advantage of this technique over ventricular injections is in the measurement of blood flow in small tissue samples when the number of microspheres deposited from ventricular injections is insufficient.