bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of strain rate on the properties of the medial collateral ligament in skeletally immature and mature rabbits: A biomechanical and histological study
Authors: Woo Savio L‐Y. , Peterson Robert H. , Ohland Karen J. , Sites Terry J. , Danto Michael I. 
Published: February 2005

AbstractThe effects of strain rate on the structural properties of the femurmedial collateral ligament‐tibia complex (FMTC) and on the mechanical (material) properties of the medial collateral ligament (MCL) of skeletally immature and skeletally mature rabbits were studied. The FMTCs were tested in tension to failure, at five extension rates (0.008 mm/s‐113 mm/s). For the FMTCs from the skeletally immature animals, values of load, elongation, and energy absorbed at failure increased substantially with extension rates. Such increases also existed for skeletally mature animals, but they were much less in magnitude. All samples from the skeletally immature animals failed by tibial avulsion, whereas samples from the skeletally mature animals failed within the ligament substance. The mechanical properties of the ligament substance were minimally strain‐rate sensitive for both groups. Histological sections of the ligament substance and insertion sites from the failed samples were examined, and these observations were correlated with the biomechanical findings. For the rabbit model used in this study, we conclude that skeletal maturity has more influence on the biomechanical properties of the MCL than does strain rate.
The collagens and glycosaminoglycans of the extracellular matrices secreted by bone marrow stromal cells cultured in vivo in diffusion chambers
Authors: Ashhurst Doreen E. , Ashton Brian A. , Owen Maureen E. 
Published: February 2005

AbstractWhen rabbit bone marrow cells are cultured in a diffusion chamber implanted into the peritoneal cavity of an athymic mouse, the stromal cells proliferate, differentiate, and produce tissues that have the morphological features of loose fibrous tissue, woven or chondroid bone, and cartilage. The collagens synthesized during the development of the tissues from 7 to 28 days after implantation were identified using specific antibodies to rabbit types I, II, III, and V and rat type IX collagens, while the glycosaminoglycans were characterized histochemically using the dye, Alcian blue. Fibrous tissue forms in the first week and it contains types I, III, and V collagens and hyaluronan. Bone and cartilage develop within the fibrous tissue from about 12 days onwards. The bone matrix contains types I and V collagens, and chondroitin and keratan sulphates. The cartilaginous matrix contains types II and IX collagens, and chondroitin and keratan sulphates. Small amounts of type III collagen are found in the bone, and types I, III, and V collagens in the cartilage. These are thought to be the remnants of the fibrous matrix and decrease as the matrices mature. It is concluded that the tissue in diffusion chambers, formed by a small number of early precursor cells present in the soft tissues of the endosteum and marrow of young rabbits, contains extracellular matrix macromolecules similar to those found in bone and cartilage.
The influence of flexibility on the economy of walking and jogging
Authors: Gleim Gilbert W. , Stachenfeld Nina S. , Nicholas James A. 
Published: February 2005

AbstractThe relationship of 11 measures of trunk and lower limb flexibility to the economy of treadmill walking and jogging as measured by steady‐state oxygen consumption (VO2) was studied. Subjects (38 women, 62 men, aged 20–;62 years) were tested at six speeds between 53.6 and 187.7 m/min. By combining scores from all flexibility tests, and beginning at speeds of 107.3 m/min, the “tightest” third used significantly less O2/m/kg (9%, p < 0.05) than the “loosest” third, with “normals” in between. Two tests, trunk rotation and lower limb turnout, gave the best separation for walking/jogging economy, with the “tightest” third differing significantly from the “loosest” (8–12%) at all speeds tested (ANOVA with Scheffe). We conclude that nonpathological musculoskeletal tightness was associated with a decreased steady‐state VO2 for treadmill walking and jogging.
Torsional strength reduction due to cortical defects in bone
Authors: Edgerton Bradley C. , An Kai‐Nan , Morrey Bernard F. 
Published: February 2005

AbstractThis study correlated torsional strength reduction with circular defect size in cortical bone, to define the “stress riser” and “open‐section” effect of the defects. The experimental model was developed and verified. Circular defects from 10 to 60% of bone diameter were then created in paired sheep femora and the bones loaded to failure. Contrary to theory, this experimental study suggests that small defects (10%) of bone diameter cause no significant torsional strength reduction. A 20% defect caused a 34% decrease in strength, representing the “stress riser” dimension. Defects between 20 and 60% of bone diameter decreased strength linearly as a function of defect size, and thus no discrete “open section” dimension was identified. For circular defects we were unable to demonstrate a discrete “open section” effect at which dramatic strength reduction is observed. These data may prove to be helpful when planning surgery that involves placing defects in bone such as for infection, biopsy, and prosthesis removal. The accepted guideline to avoid defects of greater than 50% of the bone diameter may be too great. Our data reveal this 62% reduction in torque strength and 88% energy to failure exist with a 50% circular defect.
Dose‐dependent variations in blood flow evaluation of canine nerve, nerve graft, tendon, and ligament tissue by the radiolabeled‐microsphere technique
Authors: Riggi Kayvon , Wood Michael B. , Ilstrup Duane M. 
Published: February 2005

AbstractThis study evaluates the dose‐dependent accuracy of the radionuclide‐labeled microsphere technique for blood flow evaluation in nerve, nerve graft, tendon, and ligament. In eight dogs, blood flows were determined for nerve, nerve graft, tendon, and ligament tissue by simultaneous injection of high‐ and low‐ dose microsphere with different radiolabels. The results demonstrated no significant differences in blood flow as measured from the small number of microsphere (less than 400) and the high number (more than 400) for nerve and tendon tissue. For nerve tissue, microsphere counts of 50 to 100, 100 to 200, 200 to 300, and more than 300 produced mean percentage errors of 12.74% (n= 5, SEM = 4.52), 5.45% (n = 13, SEM = 1.12), 10.22% (n = 6, SEM = 4.37), and 17.08% (n = 12, SEM = 3.30), respectively. For tendon tissue, the same microsphere subdivisions had mean percentage errors of 7.47% (n = 4, SEM = 2.66), 3.63% (n = 6, SEM = 1.34), 15.54% (n = 4, SEM = 4.43), and 12.91% (n = 1), respectively. For ligament tissue, percentage errors were consistently higher; microsphere counts of 30 to 100, 100 to 200, and 200 to 300 produced mean errors of 20.14% (n = 4, SEM = 6.38), 18.66% (n = 4, SEM = 6.24), and 25.78% (n = 2, SEM = 1.97), respectively. Although there was no direct relationship between percentage error and number of microspheres retrieved, we suggest that microsphere counts in the range of 100 to 200 should be considered acceptable for nerve and tendon in the canine. Ligament tissue seems to be less well suited to the microsphere technique; however, further study is warranted.
Monkey bone matrix induces bone formation in the athymic rat, but not in adult monkeys
Authors: Aspenberg Per , Lohmander L. Stefan , Thorngren Karl‐Göran 
Published: February 2005

AbstractDemineralized bone matrix from young and adult monkeys was implanted intramuscularly for 6 weeks in athymic rats and adult monkeys. Cartilage and bone induction was evaluated by histology and calcium content. In the athymic rat, most implants induced cartilage or bone. In the monkeys, cartilage was formed only on rare occasions and there was no sign of bone formation. We conclude that (a) adult monkey bone matrix contains bone inductive properties; (b) these properties are not sufficient to induce bone formation in adult monkey muscle sites.
A new technique for the in vitro measurement of nucleus pulposus swelling pressure
Authors: Glover M. G. , Hargens A. R. , Mahmood M. M. , Gott S. , Brown M. D. , Garfin S. R. 
Published: February 2005

AbstractSwelling of the intervertebral disc nucleus pulposus may be a contributing factor in lower back pain syndromes. We have designed and tested a new osmometer for in vitro determination of nucleus pulposus swelling pressure. The functionl principle of the osmometer involves compressing a sample of nucleus pulposus with nitrogen gas until saline pressure gradients across a 0.45‐μm Millipore filter are eliminated. Swelling pressures of both pooled dog and pooled pig lumbar disc nucleus pulposus were measured on the new osmometer and were compared with swelling pressures determined using the equilibrium dialysis technique. The osmometer measured swelling pressures comparable to those obtained by the dialysis technique. This osmometer provides a rapid, direct, and accurate measurement of swelling pressure of the nucleus pulposus.
The influence of scoliosis and ageing on proteoglycan heterogeneity in the human intervertebral disc
Authors: Melrose James , Gurr Kevin R. , Cole Tak‐Chun , Darvodelsky Anne , Ghosh Peter , Taylor Thomas K. F. 
Published: February 2005

AbstractProteoglycans (PGs) purified from 19‐year‐old male (19M), 53‐year‐old female (53F), and 15–16‐year‐old adolescent idiopathic scoliotic (AIS) disc tissues were characterised by their aggregation properties with hyaluronic acid (HA), glycosaminoglycan (GAG), and amino acid composition, electrophoretic mobilities by composite agaroe polycrylamide gel electrophoresis (CAPGE), and hydrodynamic size by Sepharose CL2B gel permeation chromatography. Proteoglycan levels were similar in the AIS and 53F discs, but considerably higher levels were found in the 19M discs. Proteoglycan populations assessed by the aforementioned criteria demonstrated a similar level of heterogeneity in the AIS and 53F discs but this differed with the 19M sample. Two small Mr, low buoyant density PG species were particularly prominent in AIS and 53F discs: these were similar to two nonaggregating PG species formerly reported by di Fabio et al.; however, the corresponding PG species in 19M discs were of somewhat different composition. Collectively, these data suggest similar processing of PGs in the AIS and 53F discs. Furthermore, the pattern of normal age changes in the PGs from AIS discs appears to be disturbed, most likely arising as a consequence of the abnormal biomechanical forces intrinsic to the deformity.
The significance of skeletal magnetic resonance imaging after open bone biopsy
Authors: Schwartz Herbert S. , Shockley T. E. , Lennington W. J. , Mackey E. S. 
Published: February 2005

AbstractThe performance of a bone biopsy results in a dramatically altered magnetic resonance image (MRI) signal in both the biopsied segment and the surrounding bone. An experimental canine model was used to determine the cause and imaging sensitivity of this postbiopsy signal change in the adjacent intraosseous contents. Six dogs were used in the study. Half of the dogs had the cortical window left open, and the other half had a polymethylmethacrylate plug inserted. After hemostatic closure, images were obtained immediately postbiopsy and 6 weeks thereafter. MRI defect length was examined on both T1 and T2 weighted sequences at both time periods. After the final image was taken at 6 weeks, the bone was harvested and examined grossly and histologically for the purpose of making pathoradiographic correlations.The results suggest that magnatic resonance imaging is a sensitive method that accurately reflects the defect caused by bone biopsy and the surrounding hemorrhage. The defect length increased in size over time. The image was slightly smaller than the corresponding histologic response. Insertion of a cortical plug had no predictable effect on defect length, which depended upon the amount of pressurization used during insertion. We conclude that MRI may be useful in the staging of intraosseous primary neoplasms of bone after bone biopsy, especially in the detection of an iatrogenically induced tumor/hemorrhage margin. This may be critical when planning an intraosseous surgical resection in which short, wide margins are anticipated.
The effect of acute denervation on the microcirculation of skeletal muscle: Rat cremaster model
Authors: Chen Long‐En , Seaber Anthony V. , Bossen Edward , Urbaniak James R. 
Published: February 2005

AbstractAlthough tissue is denervated during replantation of a severed part, tissue transfer, or muscle transplantation, there are few studies concerning the effects of acute denervation on muscle microcirculation. We have described a surgical procedure that totally denervates the rat cremaster muscle. Histological examination of the denervated tissue has given convincing evidence of nerve degeneration and skeletal muscle atrophy, accompanied by electrophysiological evidence of total denervation. The diameters of each component of the microcirculation were measured before and after denervation. Arterioles and arteries ranging in size from 10 to 70 μm in diameter were found to increase significantly in size immediately after acute denervation. Larger arteries and veins did not undergo significant diametrical increases. These findings suggest that total acute denervation significantly increases the diameter of small arteries and arterioles, thereby decreasing the resistance in the arterial bed and increasing blood flow. Since this phenomenon is of limited duration (20 min), it would appear to be ineffective in enhancing reperfusion and oxygenation at the time of reattachment of amputated parts or during vascularized tissue transfers, until methods of prolonging it for several hours or more are found.
Cell association of fretting corrosion products generated in a cell culture
Authors: Merritt Katharine , Wenz Lisa , Brown Stanley A. 
Published: February 2005

AbstractThe nature and distribution of corrosion products released into the body from orthopaedic implants remains an important issue. Various approaches to study this problem have been taken, such as the injection of metal salts, the injection of corrosion products, analysis of retrieved implants and adjacent tissue, and stimulated corrosion in vivo, with collection of body fluids and tissues for analysis. Tissue culture techniques have also been used to study the cellular response to metal salts or to corrosion or wear products that were generated in a separate environment. In this study, fretting corrosion of stainless steel plates and screws and of cobalt‐chromium alloy plates with stainless steel screws was undertaken within a cell culture. The results showed that the cell cultures remained viable despite considerable metal ion release. Nickel was released in all cultures with fretting corrosion and was found minly in the tissue culture medium (supernatant of the harvested cultures). Cobalt was detected only in those cultures with fretting corrosion of the cobalt‐chromium alloy and it was present mainly in the tissue culture medium. Chromium was released in all cultures with fretting corrosion, and it was found to be associated mainly with the cells with little in the culture medium. This compartmentalization of cell‐associated chromium and fluid‐associated cobalt and nickel supports in vivo studies showing chromium accumulation in red blood cells or tissue sites and comparatively low levels of nickel and cobalt.
Interspecies comparisons of in situ intrinsic mechanical properties of distal femoral cartilage
Authors: Athanasiou K. A. , Rosenwasser M. P. , Buckwalter J. A. , Malinin T. I. , Mow V. C. 
Published: February 2005

AbstractWe measured the in situ biomechanical properties of knee joint cartilage from five species (bovine, canine, human, monkey, and rabbit) to examine the biomechanical relevance of animal models of human knee joint injuries and osteoarthritis. In situ biphasic creep indentation experiments were performed to simultaneously determine all three intrinsic material coefficients (aggregate modulus, Poisson's ratio, and permeability) of the cartilage as represented by the linear KLM biphasic model. In addition, we also assessed the effects of load bearing on these intrinsic properties at “high” and “low” weight‐bearing regions on the distal femur. Our results indicate that significant differences exist in some of these material properties among species and sites. The aggregate modulus of the anterior patellar groove within each species is the lowest among all sites tested, and the permeability of the patellar groove cartilage is the highest and does not vary among species. Similarly, the Poisson's ratio in the patellar groove is the lowest in all species, except in the rabbit. These results lead to the conclusion that patellar groove cartilage can undergo greater and faster compression. Thus, under high compressive loads, the cartilage of the patellar groove surface can more rapidly compress to create a congruent patellofemoral joint articulation. For any given location, no differences were found in the aggregate modulus among all the species, and no correlation was found between aggregate modulus and thickness at the test site. Thus, in the process of selecting a suitable experimental animal model of human articular cartilage, it is essential to consider the significant interspecies differences of the mechanical properties.
Linear relationship between the volume of hypertrophic chondrocytes and the rate of longitudinal bone growth in growth plates
Authors: Breur G. J. , Vanenkevort B. A. , Farnum C. E. , Wilsman N. J. 
Published: February 2005

AbstractIn this study, we tested the hypothesis that hypertrophic cell volume varies directly with the rate of longitudinal bone growth. The volume of hypertrophic chondrocytes (using stereological techniques) and longitudinal bone growth per 24 h (using oxytetracycline labeling techniques) were measured in the proximal and distal radial growth plates and the proximal and distal tibial growth plates of 21‐ and 35‐day‐old hooded rats and 21‐ and 35‐day‐old Yucatan pigs. We demonstrated a high coefficient of correlation (rats 0.98, pigs 0.83) between the final volume of hypertrophic chondrocytes and the rate of longitudinal bone growth over a wide range of growth rates and volumes of hypertrophic chondrocytes. In addition, we demonstrated a positive linear relationship between the rate of longitudinal bone growth and the final volume of hypertrophic chondrocytes. The slope of the regression line was different for rats than for pigs. The relationship was independent of the location of the growth plate in the animal and the age of the animal. The data suggest that mechanisms regulating volume changes in hypertrophic chondrocytes may exist and that chondrocytic volume increase is a major determinant of the rate of longitudinal bone growth. However, the relative contribution of cellular hypertrophy to longitudinal bone growth may be different in rats than in pigs.
Type I procollagen gene expression in normal and early healing of the medial collateral and anterior cruciate ligaments in rabbits: An in situ hybridization study
Authors: Wiig M. E. , Amiel D. , Ivarsson M. , Nagineni C. N. , Wallace C. D. , Arfors K‐E. 
Published: February 2005

AbstractThe purpose of this study was to compare the levels of procollagen type I messenger RNA (mRNA) in normal and healing medial collateral ligament (MCL) and anterior cruciate ligament (ACL) in a rabbit model. Our method of injury involved a surgical model with identical partial lacerations in the midsubstance of the MCL and ACL. Paraffin sections of normal ligaments, and ligaments 3, 7, 14, and 28 days postlaceration were studied by in situ hybridization to compare and follow the level of type I procollagen mRNA in the two ligaments. A complementary DNA (cDNA) probe corresponding to α1(I) procollagen mRNA was labeled with [32P]d‐CTP. After hybridization, autoradiography, and staining of the sections, the level of procollagen mRNA was assessed by microscopic examination. A higher level of procollagen mRNA was consistently detected in normal MCL than in normal ACL, suggesting higher collagen synthetic activity in the MCL. At the injury sites of the MCL and ACL, the levels of type I procollagen mRNA increased at all postlaceration periods, reaching its highest level at 14 days postsurgery. The MCL healing site had a considerably higher level of procollagen mRNA than the ACL healing site (i.e., injury site) at all postoperative intervals. The results demonstrate that procollagen mRNA levels in MCL tissue are higher than those in ACL tissue under normal conditions, as well as in response to injury. The differences in the procollagen mRNA levels of MCL and ACL may reflect the synthesis of collagen in these tissues, and may contribute to the differences in their healing capacities.
Bypassing femoral cortical defects with cemented intramedullary stems
Authors: Larson J. E. , Chao E. Y. S. , Fitzgerald R. H. 
Published: February 2005

AbstractThe objective of this investigation was to examine the effect of cemented intramedullary stem bypass on bone torsional property in the presence of femoral cortical defect. We intended to test two hypotheses; first, intramedullary fixation without bypass will accentuate the stress concentration effect and second, there will be an optimal length of stem bypass beyond the defect. Cemented intramedullary stems were used to bypass 50% diaphyseal diameter unicortical defects in paired, fresh‐frozen canine femora. One member of each pair served as an unaltered control and all specimens were tested to failure in torsion. Both single‐tailed paired t‐test and analysis of variance were used for data analysis. Bones subjected to the cortical defect and no bypass were substantially weakened, exhibiting only 44 ± 8% of control side maximum torque (p < 0.001). Positioning of the intramedullary stem with its tip at the center of the defect provided a small degree of strength improvement, achieving 60 ± 7% of control side maximum torque. One and two diaphyseal diameter bypass, however, significantly (p < 0.01) improved bone torsional strength, resulting in 80 ± 6% and 84 ± 13% of control side maximum torque, respectively. Three diameter bypass achieved only 68 ± 8% of control side maximum torque. This significant (p < 0.05) decline in strength when compared to two diameter bypass appears to indicate that the length of stem bypass beyond the cortical defect does have an optimum, probably due to the geometric characteristics of the canine femora.