bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synovial factors and chondrocyte‐ mediated breakdown of cartilage: Inhibition by hydrocortisone
Authors: Steinberg James J. , Sledge Clement B. 
Published: February 2005

AbstractCartilage‐synovium interactions were explored in a model culture system. Bovine nasal‐cartilage discs were cocultured with minced rheumatoid synovium or synovium‐conditioned media (SCM) in the presence or absence of hydrocortisone. Cartilage breakdown was assessed by the release of proteoglycan (PG) and hydroxyproline, and matrix biosynthesis by [35S]sulfate incorporation during pulse labeling. Chondrocyte‐dependent breakdown in response to synovial factors (i.e., “catabolin” activity) was assessed by the difference in PG release between living and dead cartilages. Short‐term contact with minced synovial membrane or exposure to its products released at a distance was sufficient to induce cartilage degradation in coculture; continued exposure was not required for breakdown to persist. Conditioned media from short‐term synovial culture were similarly potent, and the induced breakdown was chondrocyte dependent. Matrix biosynthesis was inhibited in exposed cartilage but could be rapidly restored to normal on synovium removal despite the persistence of cartilage breakdown. Early hydrocortisone treatment suppressed the initiation of cartilage breakdown in cocultures and largely abolished the appearance of inductive factors in SCM. Later applications had little effect either in cocultures or in catabolin assays. We conclude that synovium‐induced breakdown is an early event and that chondrocyte catabolic mechanisms once they have been activated are sufficient to maintain breakdown at a high level. Hydrocortisone, as well as limiting proteolysis, inhibits early tissue interactions at the level of synovial catabolin production or release.
Use of lumbar trunk muscles in isometric performance of mechanically complex standing tasks
Authors: Schultz Albert , Haderspeck Karol , Warwick David , Portillo Deborah 
Published: February 2005

AbstractTen subjects performed 25 tasks isometrically while standing. Those tasks imposed substantial extension, lateral bending, and twisting moments on the lumbar spine. Mechanically complex trunk muscle actions were called for to resist those moments. Biomechanical model analyses were used to predict the trunk muscle contraction forces needed to perform those tasks, and surface myoelectric activities were measured to validate those predictions. Predictions and measurements were linearly well correlated.
Electrical osteogenesis by low direct current
Authors: Baranowski Thomas J. , Black Jonathan , Brighton Carl T. , Friedenberg Zachary B. 
Published: February 2005

AbstractA constant direct current cathode was employed in the medullary canal of the rabbit tibia to investigate electrical osteogenesis at low current levels. Currents of 0.015 or 0.075 μA were delivered to the bone and the biological response was compared with contralateral controls receiving 20 μA. This investigation was performed to determine if electrical osteogenesis occurs at current levels below the previously studied range of 1–100 μA with stainless steel electrodes. New bone formed by 0.015 μA cathodes was statistically comparable with that found around inactive cathodes from an earlier pertinent study. The osteogenic response to 0.075 μA cathodes was significantly elevated above that to inactive ones, thus substantiating electrical osteogenesis for currents below 1 μA. However, it is evident that this does not demonstrate a further stimulatory range but that currents near 0.075 μA probably approach the lower significant limit for electrically induced bone growth with stainless steel electrodes.
Effect of postoperative immobilisation on the regrowth of the knee joint semilunar cartilage: An experimental study
Authors: Ghosh P. , Taylor T. K. F. , Pettit G. D. , Horsburgh B. A. , Bellenger C. R. 
Published: February 2005

AbstractBilateral total medial meniscectomy was undertaken in the knee joints of 12 adult greyhounds. One‐half of the animals had one meniscectomised joint immobilised by an external fixation system for 5 weeks following meniscectomy. All animals were sacrificed 6 months after surgery. The menisci (regrown and normal) were examined for collagen content and analysed histochemically to assess collagen assembly and glycosaminoglycan (GAG) distribution. Although the collagen content of regrown tissues was not statistically different from normal medial or lateral menisci, the fibre development and GAGs were abnormal. It is concluded that movement following meniscectomy is likely beneficial to the matrix formation in the regenerating tissue, but this together with weight bearing may have a detrimental effect on articular cartilage of the medial joint compartment.
Relationship of isokinetic torque to isometric torque
Authors: Otis James C. , Godbold James H. 
Published: February 2005

AbstractIsokinetic muscle testing has become an increasingly popular method for measuring muscle performance. However, the relationship of isokinetic strength measurements to static strength measurements remains unclear. The relationship between maximal isokinetic and maximal isometric torque was investigated at angular velocities of 24, 48, 96, and 192°/s for both flexion and extension of the elbow joint. Twenty‐four subjects were tested bilaterally, and discrete torque values at the positions of 60 and 90° of flexion were obtained from the continuous isokinetic records for comparison with isometric torques recorded at the same two positions. Data were analyzed using an analysis of covariance with isokinetic torque, the dependent variable, expressed as a function of isometric torque and as a function of the design variables side and position. The results demonstrated significant effects of side and position and also demonstrated the dependence of isokinetic strength on velocity. Confidence intervals were determined for the prediction of isokinetic torque from observed isometric torque for normal individuals, providing a potentially useful tool to aid in the diagnosis of muscular disorders.
Natural history of healing in the repaired medial collateral ligament
Authors: Frank C. , Schachar N. , Dittrich D. 
Published: February 2005

AbstractThe purpose of this study was to assess morphologically the healing of repaired medial collateral ligaments (MCLs) in a rabbit model. Healing ligaments were examined grossly and histologically at various intervals, from 3 days to 2 ½ years after injury, and compared with the appearances of normal age‐, sex‐, and activity‐matched controls. Results show that all ligaments healed by bridging scar formation rather than true ligament regeneration. Increases in cellularity and temporary matrix disorganization along the entire length of the ligaments during healing suggest a combination of diffuse mechanical damage from their failure in tension and regional inflammatory injury (in excess of surgical exposure alone) from the processes of degradation and replacement. Substance that was not injured physically in this model demonstrated complete recovery, while that replaced by scar did not. Healing processes were similar to those of other highly specialized soft tissues (e.g., tendons), with short phases of hemorrhage and inflammation, an intermediate phase of proliferation, and a prolonged phase of remodeling. Failure of repairs to maintain anatomical apposition of torn ends may have contributed to the delay of these healing processes by increasing scar mass. Incomplete scar remodeling at 2 ½ years, however, suggests much slower MCL healing than previously reported and probably, therefore, a longer period for potential treatment influence.
Tendons and ligaments: A morphological and biochemical comparison
Authors: Amiel D. , Frank C. , Harwood F. , Fronek J. , Akeson W. 
Published: February 2005

AbstractThe purpose of this study was to compare selected rabbit tendons and ligaments morphologically and biochemically. Five representative structures from each of six age‐ and sex‐matched rabbits were compared. Biochemical analyses included total collagen, reducible collagen cross‐links, quantitative collagen typing, DNA, and glycosaminoglycans. Histological and chemical differences were demonstrated between the tendons and the ligaments. Smaller differences were also found between the individual ligaments (collateral and cruciate) and between the two tendons (patellar and Achilles) that were examined. These findings suggest that ligaments are more metabolically active than tendons, having more plump cellular nuclei, higher DNA content, larger amounts of reducible cross‐links, and the presence of more type III collagen, as compared with tendons. They also contain slightly less total collagen than tendons and more glycosaminoglycans. We conclude that the tendons and ligaments studied have unique histological and biochemical characteristics, despite their gross similarities. Relatively increased metabolic activity in ligaments, implied by our findings, may be species specific, age related (transient), or may truly represent a structural expression of functional need for more rapid adaptation. Further investigation of other similarities or differences between particular ligaments (or tendons) is indicated, and attention is directed toward the importance of such variables in development of models for tendon and ligament studies.
Fluorometric determination of DNA in cartilage of various species
Authors: Oegema Theodore R. , Carpenter Barbara J. , Thompson Roby C. 
Published: February 2005

AbstractA sensitive, modified 3,5‐diaminobenzoic acid (DABA), fluorometric DNA assay was developed and compared to mithramycin and ethidium bromide assays in determining the DNA content of dense connective tissues including: Swarm rat chondrosarcoma, rabbit, dog, monkey, and most importantly, adult human articular cartilage. In the more cellular cartilages, the three methods gave equivalent results. However, in the relatively acellular human cartilage, the DABA method was shown to be superior. Both the mithramycin and ethidium bromide gave falsely high values compared to the DABA method, which by subtraction after DNase digestion approached the DABA value. The latter was completely DNase sensitive. With the DABA method, the DNA content of human cartilage can be obtained on less than 5 mg wet weight of fresh, alcohol‐fixed, or lyophilized material. While the DNA can also be released by digestion with papain or protease from Streptomyces griseus, proteinase K was preferable. The comparison of literature values for other fluorometric and spectrophotometric assays of human cartilage suggest these methods overestimate human articular cartilage DNA concentrations, whereas the DABA values were in line with those predicted from previous morphometric analysis. Thus, the modified method represents an improvement in DNA analysis of dense connective tissues.
Development of a variable stiffness external fixation system for stabilization of segmental defects of the tibia
Authors: Tencer A. F. , Claudi B. , Pearce S. , Bucholz R. W. , Johnson K. D. 
Published: February 2005

AbstractThe mechanical properties of a variable stiffness external fixation system were explored. Initial testing of a unilateral fixator configuration demonstrated that system rigidity could be increased by maximizing pin separation distance in the fracture component and the number of pins used while minimizing pin separation distance across the fracture site and the sidebar offset distance from bone. A triangulated system composed of half pin frames mounted anteriorly and medially on the tibial aspects and linked by crossbars was devised. Progressive disassembly of the frame was shown to result in progressive decreases in fixator rigidity in all planes.
Force ratios in the quadriceps tendon and ligamentum patellae
Authors: Huberti H. H. , Hayes W. C. , Stone J. L. , Shybut G. T. 
Published: February 2005

AbstractWe measured forces in the quadriceps tendon and ligamentum patellae in six human cadaver knee joints loaded through a range of flexion angles from 30 to 120°. Using standardized loads based on one‐sixth of maximum isometric quadriceps moments reported in human volunteers, we measured maximum average forces at 60° flexion of 532 N in the quadriceps tendon (FQ) and 470 N in the ligamentum patellae (FL). Linear extrapolation to full maximum extensor moments results in estimates of 3,200 N for FQ and 2,800 N for FL. The force ration (FL/FQ) reached a maximum value of 1.27 at 30° and minimums of 0.7 at 90 and 120° knee flexion. Contrary to prevailing opinion, our results indicate that the patella is not a simple pulley that serves only to change the direction of equal forces in the quadriceps tendon and ligamentum patellae. Instead, the ratio of forces in these structures varies significantly with flexion angle. The ratio appears to be determined by the changing location of the patellofemoral contact area relative to the insertions of the tendon and ligament. These findings emphasize the biomechanical importance of patellar length and of the vertical dimensions and locations of the patellofemoral contact area. Attempts at surgical intervention for the treatment of disorders of the extensor apparatus should recognize these variations. Procedures that tend to move the contact area more proximally (at a particular flexion angle) will also tend to decrease the FL/FQ ratio.
Metal/cement interface strength in cemented stem fixation
Authors: Ahmed A. M. , Raab S. , Miller J. E. 
Published: February 2005

AbstractTo characterize the strength of the interface between stem‐type metal implants and bone cements, a fracture mechanics parameter was used. This parameter, the critical strain energy release rate (Gc), was determined from “push‐out” tests of cylindrical specimens. The specimens, formed using molds of bone, were maintained and tested at body temperature. The strength of interfaces formed with cancellous bone surrounding the cement mantle was significantly less than the strength of those formed in apposition to cortical bone. A marked degradation of strength was found with saline immersion for SS316LVM/cement interfaces formed with Zimmer regular, Simplex‐P, and Zimmer LVC cements. After 60 days of immersion the interface Gc was only 10–20% of the value for bulk cement. Interfaces formed with thin‐film polymethylmetharcrylate‐precoated metals (SS316LVM, Co‐Cr‐Mo, and Ti‐6A1‐4V) yielded “dry” Gc values one order of magnitude greater than those measured with interfaces formed with uncoated metals. Moreover, the strength of precoated SS316LVM/cement interfaces formed with all three brands of cement did not change after saline immersion for 60 days.
Ultrastructure of sensory nerve endings in monkey (Macaca fascicularis) knee joint capsule
Authors: Halata Zdenek , Badalamente Marie A. , Dee Roger , Propper Michael 
Published: February 2005

AbstractUltrastructural studies of sensory endings in monkey posterior medial knee joint capsule were undertaken. Three distinct sensory nerve endings have been identified: free nerve endings, Ruffini corpuscles, and Pacinian corpuscles. The free nerve endings are present in all layers of the joint capsule excluding the synovium. Two types of Ruffini corpuscles have been found in the fibrous layer. The first type is characterized by a thin perineurial capsule, the second type by a thicker perineurial capsule, and extensive intracapsular space. Both types of Ruffini corpuscles are innervated by approximately one to four myelinated axons which lose their sheaths as they course through the corpuscle. They terminate on collagen fiber bundles as distinct swellings with spiny membrane projections that are covered by a thin basal lamina. These terminals contain abundant mitochondria, agranular vesicles, and irregularly arranged neurofilaments and neurotubules. Two types of Pacinian corpuscles were occasionally observed. The first was a small, typically laminated structure with an inner core at the layer between the synovium and the fibrous layer and between the fibrous layer and muscle/ligament; larger Vater‐Pacinian corpuscles were noted only at the boundary between the fibrous layer and the muscle/ligament layer.
Characterization of growth plate mitochondria
Authors: Stambough J. L. , Brighton C. T. , Iannotti J. P. , Storey B. T. 
Published: February 2005

AbstractThe growth plate chondrocyte plays a central role in growth plate function. The purpose of this study was to characterize the respiratory and calcium transport properties of isolated mammalian growth plate chondrocytes and mitochondria obtained from these cells and to quantitate the mitochondrial weight and volume fraction in each zone of the growth plate. A new method was developed for isolation of mitochondria from chondrocyte suspensions. Isolated chondrocyte mitochondria demonstrated an eightfold increase in oxygen consumption in response to calcium and a two‐ to threefold increase in oxygen consumption in response to adenosine diphosphate. Similar responses were observed in chondrocytes treated with digitonin. The mitochondrial protein content of the growth plate and hyaline cartilage chondrocytes is significantly less than hepatocytes. Conversely, the chondrocyte mitochondrial cytochrome aa3 content is similar to mitochondria from a wide variety of sources. A zonal analysis of the growth plate demonstrates an increase in the mitochondrial weight (protein) fraction from the reserve to the hypertrophic zone whereas the mitochondrial volume fraction decreases from the reserve to the hypertrophic zone. The findings of this study emphasize the dependence of chondrocytes on glycolysis as a prime energy source and support the concept that chondrocyte mitochondria have become specialized in the process of matrix calcification.
Quantification of regional blood flow to canine flexor tendons
Authors: Weidman Kevin A. , Simonet William T. , Wood Michael B. , Cooney William P. , Ilstrup Duane M. 
Published: February 2005

AbstractAlthough the blood supply and the microcirculation of flexor tendons have been studied and defined extensively using qualitative methods, the quantitative assessment of blood flow has been lacking because of the limitations of the available experimental techniques. We studied the regional blood supply to the flexor tendons of dogs by the technique of radionuclide‐labeled microspheres. Seven adult mongrel dogs were used. Microsphere injection and tissue‐counting techniques previously used for other tissues were applied. Samples of proximal, isthmus, and distal portions of the profundus and superficialis flexor tendons were harvested from each digital unit of available limbs from each dog. Mean (± SE) flows (ml/100 g dry tissue/min) were proximal profundus 1.78 ± 0.60 and superficialis 7.10 ± 1.50. The differences were significant (p < 0.01). The study suggests that regional variation in blood flow to canine digital flexor tendons exists, so that a single value for blood flow to these tendons is not relevant. Furthermore, the study supports the concept of dual (vascular and synovial) nutrition to the digital flexor tendons in dogs. These observations may have implications regarding tendon repair techniques.
Clinical utility of the erythrocyte sedimentation rate in preoperative evaluation of solitary skeletal lesions
Authors: Simon Michael A. , Schaaf H. William , Metz Charles E. 
Published: February 2005

AbstractWe investigated the utility of the erythrocyte sedimentation rate in planning the diagnostic and surgical strategy for patients who were found by conventional radiography to have a solitary skeletal lesion. A series of 101 patients was separated into two groups according to their ultimate diagnoses. Group I included patients with skeletal metastases of unknown origin, unusual bone infections, and marrow cell tumors. Group II included benign and malignant primary bone tumors. Using the Westergren method to determine the erythrocyte sedimentation rate prior to biopsy, we found that only one of 65 Group II patients had a rate above 30 mm/h whereas 22 of 36 Group I patients had rates greater than 60 mm/h. By using Receiver Operating Characteristic analysis, we estimated the trade‐offs between sensitivity and specificity that can be achieved with various threshold sedimentation rates. In particular, we found that a critical erythrocyte sedimentation rate of 30 mm/h allows separation of Group II patients from Group I patients with 96.9% sensitivity and 82.6% specificity. Our results indicate that the erythrocyte sedimentation rate can be used effectively in conjunction with conventional radiography in the planning of an appropriate further diagnostic strategy.
Bone density in women: A modified procedure for measurement of distal radial density
Authors: Awbrey B. J. , Jacobson P. C. , Grubb S. A. , McCartney W. H. , Vincent L. M. , Talmage R. V. 
Published: February 2005

AbstractThis is a cross‐sectional study of bone densitometry in >700 normal healthy white women ranging in age from 18 to 98 years. A modified procedure for single–photon bone density analysis of the distal radius is described and compared with dual‐photon densitometric measurements of the second through fourth lumbar vertebrae. The distal radial site measured was separated from the ulna by 5 mm. This “5 mm” site was characterized according to trabecular and cortical bone content, measurement reproducibility, positioning precision, and the effects of wrist pronation or supination. The radial site demonstrated a bone density loss of <0.1%/year for normal women 25–50 years of age, increasing to 0.7%/year after 50 years of age. In contrast to the variability and inconsistency obtained by us and others utilizing the standard “9/10” site, bone loss with age at the new “5 mm” site correlated closely with generalized bone mineral loss of the axial skeleton. We suggest that there is a unique role for single‐beam densitometric measurements of the radius, permitting the rapid and relatively inexpensive evaluation of large populations of women without requiring a visit to a medical center. Such a process can select those requiring further evaluation or medical attention.
Effect of antigen‐induced synovitis on the extensor tendons within the retinacular compartment of the dog
Authors: Manske Paul R. , Lesker Peggy A. 
Published: February 2005

AbstractAntigen‐induced proliferative synovitis was produced within the extensor retinacular compartment of one forepaw of young littermate dogs. The extensor tendons within the synovitis compartment were compared with the tendons in control compartments of the opposite forepaw. At 7 days following challenge, the tendons from the proliferative synovitis compartment showed increased uptake of [3H]proline at 5 min after pulse labeling. At 7, 14, and 28 days following challenge, the tendons within the proliferative synovitis compartment showed a significant increase in metabolic activity compared with control tendons after radioactive labeling for 6 h, with no associated difference in total collagen content of the control and synovitis tendons. These results indicate an increase in protein synthesis and degradation by the synovitis‐surrounded tendons.