bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proliferative and synthetic response of bovine growth plate chondrocytes to various capacitively coupled electrical fields
Authors: Brighton Carl T. , Jensen Loren , Pollack Solomon R. , Tolin Brad S. , Clark Charles C. 
Published: February 2005

AbstractIn vitro monolayer cultures of growth plate chondrocytes isolated from newborn calf costochondral junctions were subjected to capacitively coupled electrical fields for 48 h. In part A, the electrical signal was a 60‐kHz sine wave applied at different voltages so as to produce electrical fields at the pericellular level of 7, 20, 50, and 126 mV/cm. Incorporations of [3H]thymidine and [35S]sulfate were assayed to determine the effect of the above fields on cell proliferation and matrix synthesis, respectively. Proliferation was increased by 47% in the 20 mV/cm field whereas the same field decreased [35S]sulfate incorporation by 21%. These changes were significant at p < 0.05 in both instances. In part B, the 20 mV/cm field was applied in a pulsed fashion to produce daily duty cycles of 100. 25, 2, and 0.25%. Incorporation of [3H]thymidine, [35S]sulfate, and [14C]proline per DNA were assayed. Results indicated that the 100, 25, and 0.25% percent duty cycles showed significantly (p < 0.01–0.05) increased proliferation, whereas the 0.25% signal (5 ms on/495 ms off for 6 h/day) significantly decreased [14C]proline incorporation. We conclude that the biologic response of cells in vitro is signal specific, and that the total amount of electrical energy required to stimulate the growth plate chondrocyte to increased proliferation is very small since the total time the 0.25% duty cycle signal was only 3.6 min of a 24‐h period.
Drug‐induced inhibition of proteoglycanase activity in the hulth–telhag model
Authors: Ishizue Kenneth K. , Ehrlich Michael G. , Mankin Henry J. 
Published: February 2005

AbstractEvidence has accumulated that there are increased degradative enzymes in osteoarthritis responsible for joint destruction. These enzymes are metal‐dependent, and inhibited by EDTA. EDTA was administered intraarticularly to rabbits in an experimental model of osteoarthritis. There was a 25% reduction in neutral proteoglycanase activity and 75% of the animals had a reduction in the severity of the arthritis as measured on a histologic‐histochemical grading system. It is suggested that future chemotherapeutic studies on arthritis might focus on enzyme inhibition.
Repeatability of kinematic, kinetic, and electromyographic data in normal adult gait
Authors: Kadaba M. P. , Ramakrishnan H. K. , Wootten M. E. , Gainey J. , Gorton G. , Cochran G. V. B. 
Published: February 2005

AbstractThe repeatability of gait variables is an important consideration in the clinical use of results of quantitative gait analysis. Statistical measures were used to evaluate repeatability of kinematic, kinetic, and electromyographic data waveforms and spatiotemporal parameters of 40 normal subjects. Subjects were evaluated three times on each test day and on three different test days while walking at their preferred or natural speed. Intrasubject repeatability was excellent for kinematic data in the sagittal plane both within a test day as well as between test days. For joint angle motion in the frontal and transverse planes, the repeatability was good within a test day and poor between test days. Poor between‐day repeatability of joint angle motion in the frontal and transverse planes was noted to be partly due to variabilities in the alignment of markers. Vertical reaction and fore–aft shear forces were more repeatable than the mediolateral shear force. Sagittal plane joint moments were more repeatable than frontal or transverse plane moments. For electromyographic data, repeatability within a day was slightly better than between test days. In general, the results demonstrate that with the subjects walking at their natural or preferred spped, the gait variables are quite repeatable. These observations suggest that it may be reasonable to base significant clinical decisions on the results of a single gait evaluation.
Effect of age on the abundance and fragmentation of link protein of the human intervertebral disc
Authors: Pearce R. H. , Mathieson J. M. , Mort J. S. , Roughley P. J. 
Published: February 2005

AbstractThe link proteins of the human intervertebral disc were studied in tissue extracts by sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS/PAGE), followed by immunoblotting, using a specific monoclonal antibody. Three link proteins were detected, corresponding in electrophoretic mobility to those present in articular cartilage. As with articular cartilage, the largest link protein predominates in the young, whereas in the adult the smallest link protein is equally abundant and internal fragmentation of the link proteins occurs. Only in the newborn is the quantity of extractable link protein comparable to that from articular cartilage. In the adult, the disc contains much less link protein than is present in autologous articular cartilage. Neither the amount nor heterogeneity of the link protein differs among different levels within the lumbar spine, although the proportions of the three proteins can differ between the anulus fibrosus and nucleus pulposus. The anulus always contained more extractable link protein, relative to tissue wet weight than the nucleus, and the nuclear link protein, at least in adolescents, contained a greater proportion of the smallest link protein. Such changes in the quantity and structure of the disc link proteins may affect the properties of the proteoglycan aggregates and, thus, could influence disc function.
Cytochemical evidence for a proteoglycan‐associated filamentous network in ligament extracellular matrix
Authors: Bray D. F. , Frank C. B. , Bray R. C. 
Published: February 2005

AbstractThe purpose of this investigation was to examine the extracellular matrix of rabbit ligament before and after digestion with glycosaminoglycan degrading enzymes. In order to preserve and enhance the visibility of negatively charged tissue components, particularly the glycosaminoglycancontaining proteoglycans, the, cationic stains ruthenium red (RR) and ruthenium hexammine trichloride (RHT) were used. Cross‐sections of the midsubstance of 10‐month‐old (mature) rabbit medial collateral ligaments fixed using conventional procedures revealed a sparse population of stellate‐shaped cells that did not appear to be interconnected. Similar tissue fixed in either RR or RHT showed an extensive network of thin, electron‐dense “seams” that interconnected cells and appeared to irregularly subdivide the extracellular matrix (ECM). These seams mainly consisted of a meshwork of microfilaments throughout which small granules were dispersed. Numerous 14‐nm microfibrils, as well as mature elastic fibers were also present within the seams. The size and shape of the microfilaments, together with their threadlike, beaded appearance suggested that they could be Type VI collagen. The seam granules were easily removed with chondroitinase ABC, chondroitinase AC II, and mild (0.18 M) salt treatment. Only chondroitinase ABC succeeded in removing additional granules, tentatively identified as proteodermatan sulphate molecules, that were periodically located at d band sites along the Type I collagen fibrils. These results suggest that the seam granules are not dermatan sulphate containing proteoglycans, and further, that these proteoglycans may be sequestered into specific zones within the ECM through loose association with the seam microfilaments. While the functional significance of the seams remains unknown and their specific composition clearly requires further study, it is likely that they represent important functional (e.g., viscoelastic) or biological (e.g., nutritional) subdivisions of ligament substance.
Transplantation of the rabbit medial collateral ligament. I. Biomechanical evaluation of fresh autografts
Authors: Sabiston P. , Frank C. , Lam T. , Shrive N. 
Published: February 2005

AbstractThis investigation was designed to study the biomechanical recovery of a free bone‐ligament‐bone graft that was returned to its normal extraarticular position, with as little disturbance to its mechanical and biological environments as possible. Twenty‐five adult New Zealand white rabbits had their right bone‐medial collateral ligament (MCL)‐bone complex removed completely and replaced immediately using internal fixation. Animals were allowed unrestricted cage activity before sacrifice in groups of five at intervals of 3, 6, 12, 24, and 48 weeks posttransplantation. Contralateral legs served as internal controls and a separate series of normal animals served as external controls. All MCLs were tested biomechanically using a detailed testing protocol. Results showed early deterioration of 20–35% in autograft complex structural behavior, with weakening of both ligament substance and insertions. Viscoelastic behavior of these ligaments was also affected, showing increases in the amount of both cyclic load‐relaxation and static load‐relaxation at early healing intervals. These properties were statistically indistinguishable, however, from controls at 48 weeks. Failure behavior of autografts was even better preserved, reaching a low of 65% of control values at 24 weeks and recovering to within 10% of controls at 48 weeks. These results, plus the major changes in failure modes that occurred over that duration, suggest that autograft incorporation is a slow but dynamic process. These results further suggest that at least some connective tissue autografts, when placed under, as yet undefined, “proper biological and mechanical conditions,” can retain and recover a number of biomechanical properties over a period of 1 year. The longer‐term fate of these autografts and the exact nature of their similarities or differences from other graft alternatives (e.g., tendon for ligament), however, is unknown.
Stability of initial fixation of the tibial component in cementless total knee arthroplasty
Authors: Shimagaki Hitoshi , Bechtold Joan E. , Sherman Robert E. , Gustilo Ramon B. 
Published: February 2005

AbstractThis study measured the vertical displacement of three kinds of cementless tibial components [Porous Coated Anatomical (PCA), Tricon, and Whiteside], under eccentric loading up to 2,225 N. Displacement between the tibial tray and the proximal tibia was measured with linear variable differential transformers at the anterior and posterior side when anteriorly or posteriorly loaded, and at the medial and lateral side when medially or laterally loaded. The general pattern of motion was sinking at the loaded side and lift‐off at the opposite side and lift‐off at the opposite side. Lift‐off opposite the loaded side was fairly small for all components at all measurement sites. Among the three components, the Whiteside showed the smallest displacements. The Tricon (when anteriorly or posteriorly loaded), and the PCA (when medially or laterally loaded) showed sinking at the loaded side. Anterior screw fixation of the PCA was not effective in preventing anterior lift‐off. The tilting motion of the tibial components obseved in this study implies instability of the initial fixation, which could possibly compromise bony ingrowth. Furthermore, this tilting could cause uneven distribution of load, and potentially result in fracture of the underlying bone.
In vitro and in vivo effects of metal chelators on cartilage metabolism
Authors: Ehrlich Michael G. , Stefanich Ray , Ishizue Kenneth K. , Armstrong Ann L. , Mankin Henry J. 
Published: February 2005

AbstractThe effect of metallic chelating agents (EDTA, EGTA) on cartilage metabolism was studied both in vitro, on calf cartilage, and in vivo, in rabbits. The question asked was whether it was possible to affect neutral protease activity, and not also inhibit beneficial synthetic systems. In vitro, EDTA suppressed anabolic processes, while EGTA had no effect. However, EDTA in vivo did not suppress glycosaminoglycan or RNA production, but paradoxically stimulated them. At the same time, EDTA inhibited neutral protease activity in normal animals.
Quantitative analysis of cold stress performance after digital replantation
Authors: Nunley James A. , Penny Wade H. , Woodbury Max A. , Koman L. Andrew 
Published: February 2005

AbstractIsolated cold stress testing (ICST) has been used to assess cold stress performance or digital thermoregulation, but statistical analysis of the results has been limited to visual comparisons of data. In this prospective study, 11 patients who underwent complete digital replantation were followed serially with ICST at 6 weeks, 3 months, 6 months, 1 year, and 2 years post‐operatively, and the results were analyzed quantitatively. For that analysis, we devised a mathematical method that provided a cooling and a warming coefficient to fit the data. Differences in these cooling and warming coefficients were then regressed against time after replantation, patient age, number of digits replanted, hand dominance, and clinical evidence of sensory recovery. There was a significant correlation between response to isolated cold stress testing (thermoregulation) and degree of sensory recovery (p ⩽ 0.02). This method for quantitative analysis of isolated cold stress testing data allows objective evaluation of digital blood flow patterns based on temperature, thereby providing a reliable and objective assessment of the recovery of thermoregulation in the replanted human digit.
Changes in the orientation of proteoglycans during the early development of natural murine osteoarthritis
Authors: Dunham Jane , Chambers M. G. , Jasani M. K. , Bitensky Lucille , Chayen J. 
Published: February 2005

AbstractAt least 80% of male STR/ORT mice naturally develop osteoarthritis that predominantly affects the medial tibial cartilage. Overt osteoarthritic changes, as judged by radiological and histological abnormalities, become apparent after 30 weeks of age. Consequently, mice < 30 weeks of age were used to investigate early changes in the cartilage matrix related to the natural development of osteoarthritis, without the need for experimental intervention to induce this condition. Quantitative Alcian blue staining showed little change in the total amount of proteoglycans in mice of this age. Polarized light microscopy of the birefringence induced by such staining demonstrated a progressive decline in the orientation of the proteoglycans in the medial cartilage of these mice. This decline was not found in CBA mice, which only very rarely develop osteoarthritis of this joint. Such progressive disorganization of the proteoglycans would be likely to permit the increased free water‐content characteristic of osteoarthritic cartilage.
Mechanism of action of parathyroid hormone‐induced proteoglycan synthesis in the growth plate chondrocyte
Authors: Iannotti J. P. , Brighton C. T. , Iannotti V. , Ohishi T. 
Published: February 2005

AbstractIn the growth plate chondrocyte, parathyroid hormone (PTH) stimulates phosphoinositol 4, 5 bisphosphate (PIP2) degradation, which results in the rapid production of inositol (1,4,5) triphosphate (IP3). IP3 induced the release of calcium from an intracellular store, which caused a rapid increase in the cytosolic ionized calcium concentration. Parathyroid hormone also induced a 30–50% increase in proteoglycan synthesis. Phorbol esters, which pharmacologically activate protein kinase C, resulted in a 70–80% increase in proteoglycan synthesis. Treatment of the chondrocytes with retinoic acid (0.2 μM) inhibited the parathyroid hormone and phorbol ester‐induced increase in intracellular ionized calcium and the increase in proteoglycan synthesis. From this data we postulate that the stimulation of proteoglycan synthesis in growth plate chondrocytes by PTH is mediated by the breakdown of membrane phosphoinositides, which results in the production of IP3 and an increase in ionized intracellular calcium. It is suggested that the degradation of membrane phosphoinositides also results in production of diacylglycerol and, thereby, an activation of protein kinase C, which has a large stimulatory effect on proteoglycan synthesis. The increase in cytosolic calcium most likely acts synergetically with diacylglycerol to activate protein kinase C. Retinoic acid blocks the effect of PTH and phorbol ester‐induced proteoglycan synthesis and may act through the inhibition of protein kinase C. The overall effect of PTH on the growth plate chondrocyte appears to be a stimulation of proteoglycan synthesis that is mediated by the degradation products of membrane phosphoinositides.
Vertebral end‐plate failure in porcine‐and bovine models of spinal fracture instrumentation
Authors: Allan D. Gordon , Russell G. Gordon , Moreau Marc J. , Raso V. James , Budney David 
Published: February 2005

AbstractThe use of mature porcine and immature bovine spines as models for the assessment of spinal fracture instrumentation is commonplace. By comparing the load‐displacement characteristics of these spine segments and observing the fracture type, this study investigated the tendency of immature bovine spines to fail prematurely at the vertebral physis, disrupting biomechanical evaluation of spinal fracture fixation devices. Load to failure of the spines was determined using the Instron Universal Testing Machine and a specially designed endcap. In axial compression, the 10–16‐week‐old calf spines failed at 12,845 ± 1,466 N, compared with mature pig spines at 17,300 ± 5,170 N (p < 0.05). Axial compression with flexion caused consistent failure through an end‐plate in both species: 995 ± 156 N for the calf spines and 2,025 ± 575 N for the porcine spines (p < 0.005). It was concluded that the tendency for immature bovine spines to fail more readily at the cartilaginous end‐plate makes the calf spine a less desirable model.
Control of transmission of HIV and other bloodborne pathogens in biomechanical cadaveric testing
Authors: Cavanaugh John M. , King Albert I. 
Published: February 2005

AbstractThe Bioengineering Center at Wayne State University uses universal blood and body fluid precautions when handling human cadavers in bio‐mechanical testing. Our infection control protocol largely follows the precautions outlined by the Centers for Disease Control (CDC). In addition, we screen each cadaver for the human immunodeficiency virus (HIV) and the hepatitis B virus (HBV) before accepting a cadaver for biomechanical tests. This paper discusses acquired immunodeficiency syndrome (AIDS) and infection control guidelines by addressing the following: (a) what is AIDS? (b) How infectious is the HIV virus, which causes AIDS? (c) What precautions should be taken in cadaveric testing to safeguard against HIV and other bloodborne pathogens? The infection control procedures presented in this paper can be adapted to whole‐body cadaveric testing or to the testing of tissue specimens.
In situ cross‐linking of cartilage proteoglycans
Authors: Phillips Frank M. , Pottenger Lawrence A. , Hay Rick V. 
Published: February 2005

AbstractAlthough the in vitro interactions between purified cartilage matrix components have been studied extensively, little is known about these interactions in situ. In this study, cartilage was treated with a cross‐linking reagent with a span of 1.2 nm between its reactive terminal groups in order to preserve the native relationships between closely associated matrix components throughout extraction, purification, and preparation for electron microscopy. After in situ cross‐linking, electron microscopy and gel chromatography revealed that about one‐half of the guanidine hydrochloride extractable proteoglycans were polymeric, usually with two to five proteoglycan subunits in each polymer. Cross‐linking consistently involved the thin segments of the proteoglycan subunits. Some of the proteoglycan polymers were capable of binding hyaluronic acid and were parts of aggregates under associative conditions. SDS–polyacrylamide gel electrophoresis revealed that link proteins were present within the polymers, and studies in which purified proteoglycans were cross‐linked in vitro confirmed that the link proteins increased the proportion of polymeric proteoglycans. These findings suggest that individual proteoglycans within cartilage have intimate associations with other proteoglycans that are mediated by link proteins.
Internal remodeling of periosteal new bone during fracture healing
Authors: Aro Hannu T. , Wippermann Burkhard W. , Hodgson Stephen F. , Chao Edmund Y. S. 
Published: February 2005

AbstractA closed fracture model of the rat tibia was employed to study internal remodeling of periosteal new bone during fracture repair. Static histomorphometric parameters of osteoid surface (or perimeter) and eroded surface (resorption surface) were used as indicators of appositional bone formation and resorption of bone trabeculae, respectively. Intracortical remodeling at the fracture site was evaluated using quantitative tetracycline histology and microradiography. The extents of osteoid and eroded bone surfaces did not differ significantly in the periosteal woven new bone in the early phases of fracture healing. Later on, the periosteal new bone had significantly more osteoid surface than eroded surface (p < 0.001). The number of osteoclasts also decreased significantly over time during fracture healing (p = 0.028). Cortical bone showed a continuous increase of porosity (p < 0.01) between 1 and 6 weeks after fracture. These results suggest that there is a time‐related change in the balance of periosteal bone formation and resorption during the progress of fracture repair. We hypothesize that this change was related to the restoration of bony continuity. Further studies are, however, needed to indicate the histomorphometric features of periosteal new bone in fracture nonunions.
Magnetic resonance imaging of meniscal degeneration in asymptomatic knees
Authors: Negendank William G. , Fernandez‐Madrid Felix R. , Heilbrun Lance K. , Teitge Robert A. 
Published: February 2005

AbstractHistopathological studies have suggested that spontaneous degeneration of knee menisci predisposes to symptomatic tears. We used magnetic resonance (MR) imaging to study noninvasively 20 patients with documented meniscal tears in one knee but asymptomatic contralateral knees, 18 normal controls, and 15 patients with symptomatic nonmeniscal knee disorders. A scoring system for MR signal changes was developed, and differences between the three groups were tested for significance by a multivariate analysis of covariance. MR signal changes in the menisci begin at around 30 years of age, progress with age, occur in both men and women, and occur in subjects who are inactive as well as those who undergo habitual knee stress exercises. Most subjects with documented meniscal tears in one knee have MR signals in the asymptomatic contralateral knee that reflect a more advanced degree of meniscal degeneration than in age‐comparable normal controls or patients with nonmeniscal knee disorders. After adjustment for potential confounding variables, weight, and sex, the mean scores in the asymptomatic knee of patients with meniscal disease are significantly higher than those of normal controls (p = 0.021) and nonmeniscal disease patients (p = 0.019). These results document the occurrence of age‐dependent degeneration within knee menisci, and support the hypothesis that a segment of the population has pre‐existing meniscal degeneration predisposing them to traumatic or spontaneous meniscal tears.