bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pulsed magnetic fields improve osteoblast activity during the repair of an experimental osseous defect
Authors: Canè Valerio , Botti Paolo , Soana Silvana 
Published: February 2005

AbstractThe influence of pulsed low‐frequency electromagnetic fields (PEMFs) on bone formation was investigated in studies of the healing process of transcortical holes, bored at the diaphyseal region of metacarpal bones of six adult horses, exposed for 30 days to PEMFs (28 G peak amplitude, 1.3 ms rise time, and 75 Hz repetition rate). A pair of Helmholtz coils, continuously powered by a pulse generator, was applied for 30 days to the left metacarpal bone, through which two holes, of equal diameter and depth, had been bored at the diaphyseal region. Two equal holes, bored at the same level in the right metacarpal and surrounded by an inactive pair of Helmholtz coils, were used as controls. All horses were given an intravenous injection of 25–30 mg/kg of tetracyline chloride on the 15th and again on the 25th day after the operation and were killed 5 days later. The histomorphometric analysis indicated that both the amount of bone formed during 30 days and the mineral apposition rate during 10 days (deduced from the interval between the two tetracycline labels) were significantly greater (p < 0.01 and p < 0.0001, respectively) in the PEMF‐treated holes than in the controls. As did a previous investigation, these preliminary findings indicate that PEMFs at low frequency not only stimulate bone repair but also seem to improve the osteogenic phase of the healing process, at least in our experimental conditions.
Proteoglycan synthesis in canine intervertebral discs after long‐distance running training
Authors: Puustjärvi K. , Lammi M. , Kiviranta I. , Helminen H. J. , Tammi M. 
Published: February 2005

AbstractThe alterations and distribution of proteoglycan (PG) synthesis in the intervertebral discs of young dogs exercised with long‐distance running (40 km/day) were studied with a method based on image analysis of tissue sections. Ten dogs were run on a treadmill daily for 55 weeks, and 10 dogs from the same litters served as controls. The daily running distance gradually was increased to 40 km and was maintained at that level for the final 15 weeks. Midsagittal disc segments C7‐T1, T8‐9, and L1‐2 were labeled with 35SO4, and histological sections of the segments were apposed against autoradiographic film to determine the synthesis of PGs. Next, the same sections were stained with safranin O to estimate possible alterations in PG concentration. The radiographs and stained sections were digitized with a flatbed scanner and measured by image analysis. The lumbar discs of the runners displayed a significantly lower rate of 35SO4 incorporation, while a tendency toward enhanced incorporation was seen in the cervical and thoracic discs. Safranin O staining showed a pattern just opposite to 35SO4 incorporation: decreased staining in the cervical and thoracic discs and increased staining in the lumbar disc of the runners. The results demonstrate qualitatively different influences of long‐term running training on PG metabolism at the cervical, thoracic, and lumbar levels in young dogs.
Electromyographic studies of the lumbar trunk musculature during the generation of low‐level trunk acceleration
Authors: Marras W. S. , Mirka G. A. 
Published: February 2005

AbstractAn understanding of how the support mechanisms of the spine behave during lifting may yield insight into the loading of the spine under occupational conditions and help shed light on the etiology of low‐back disorders. Previous controlled laboratory studies of spinal loadings have been limited to isometric and isokinetic conditions. To evaluate the behavior of the trunk during acceleration, we recorded intra‐abdominal pressure and trunk muscle activities during low‐level acceleration. Twenty subjects performed controlled accelerations of the trunk under different trunk loading conditions. Muscle activity decreased as acceleration increased; however, the rate of decrease differed among muscles (mean decrease, ⩽1% of maximum per 10°/s2 increase in acceleration), with the activity of the erector spinae muscles decreasing the most (1.88% of the maximum per 10°/s2 increase in acceleration). No changes in intra‐abdominal pressure were found as a function of acceleration. Relative coactivation of the muscles increased; however, this was a function of increases in trunk velocity and torque.
The effects of acidosis and alkalosis on long bone vascular resistance
Authors: Davis Timothy R. C. , Wood Michael B. 
Published: February 2005

AbstractThis study used an ex vivo perfusion model to investigate the direct effects of acidosis and alkalosis on the vascular resistance of the canine tibia. Baseline vascular resistance (BVR) and the vascular smooth muscle response to bolus doses of norepinephrine (NE) (0.025–3.2 nmol) and periarterial sympathetic nerve stimulation (NS) (10–25 Hz: 9 V, 2 ms pulses, 10 s) were studied. In Group I, these parameters were measured at normal pH (duration 7.34–7.44) and then during acidosis (pH 7.2–7.33). In Group II, they were measured at normal pH and then during alkalosis (pH 7.47–7.58). In Group III (control), they were measured serially at a normal pH. Alkalosis increased BVR by 56% (p < 0.0001). Acidosis attenuated (18% reduction) and alkalosis enhanced (66% increase) the vasoconstrictor action of NE (p < 0.0001). Acidosis also attenuated (11% reduction) the effect of sympathetic NS (p = 0.012). It is concluded that perfusion pH influences the sensitivity of long bone resistance vessels to circulating NE and sympathetic NS. Thus, local concentration of hydrogen ions may provide bone with a mechanism to autoregulate blood flow.
Primary culture of microvascular endothelial cells from canine meniscus
Authors: Miller Raymond R. , Rydell Pamela A. 
Published: February 2005

AbstractMicrovascular endothelial cells were isolated and cloned from canine knee menisci. Intitially, the endothelial cell colonies in culture exhibited a cobblestone morphology. With passage and time, these cultures adopted a fibroblastic or fusiform morphology. The endothelial nature of the cells was demonstrated by positive immunostaining with antibodies to von Willebrand factor, laminin, and type‐IV collagen and by capillary‐like tube formation on Matrigel. These endothelial cells could be passaged as many as 10 times with retention of the endothelial characteristics. This population of meniscal microvascular endothelial cells will facilitate studies on the role of blood vessels in meniscal repair.
Calcium‐dependent neutral proteinase (calpain) in fracture healing in rats
Authors: Nakagawa Yasuaki , Shimizu Katsuji , Hamamoto Takashi , Suzuki Kiichi , Ueda Michiko , Yamamuro Takao 
Published: February 2005

AbstractCalpain refers to Ca2+‐dependent neutral cysteine proteinase, which originally was thought to be an intracellular proteinase but recently has been shown to function extracellularly as well. This report describes the immunohistochemical demonstration of calpain and biochemical changes in the amount of calpain during fracture healing in rats. The tibiae of 6‐week‐old Wistar rats were fractured, and calluses were obtained 5–28 days after fracture. A frozen section of the fracture callus was stained by the immunoperoxidase method with use of polyclonal antibodies of calpains I and II. Positive staining was noted with the anti‐calpain II antibody in the perivascular areas, chondrocytes, and cartilage matrix in calluses at 5, 7, and 10 days. Less intense staining was seen in older calluses. The caseinolytic activity of calpain II reached its maximum on the 5th day, was high on the 7th and 10th days, and decreased rapidly thereafter. The quantity of calpain II was dependent on the process of fracture healing. It was concluded that calpain was working as one of the matrix proteinases in fracture callus.
Articular cartilage thickness and glycosaminoglycan distribution in the young canine knee joint after remobilization of the immobilized limb
Authors: Kiviranta Ilkka , Tammi Markku , Jurvelin Jukka , Arokoski Jari , Säämänen Anna‐Marja , Helminen Heikki J. 
Published: February 2005

AbstractThe recovery of articular cartilage from atrophy induced by joint immobilization was investigated in immature dogs. In a previous study, we showed that 11 weeks of immobilization of the knee (stifle) joint of young dogs reduced the concentration of articular cartilage glycosaminoglycans (GAGs) by 13–47%. In the present study, right hindlimbs from six female beagles were immobilized for 11 weeks, as in the previous study, and then were remobilized for 15 weeks. Cartilage from the knee joint was compared with cartilage from nonimmobilized knees of eight age‐matched control beagles. Histological samples taken from 11 different locations of the knee joint were stained with safranin O, and microspectrophotometry was used to demonstrate distribution of GAGs in the tissue. After remobilization, GAG concentration was restored in the patellofemoral region and tibial condyles. On the summits of the femoral condyles, and especially at the periphery of the femoral condyles, GAG concentration remained 8–26% less than the control values. On the summits, the thickness of the uncalcified cartilage was as much as 15% less than in the age‐matched controls. Consequently, the changes induced by unloading were reversible to a great extent, but a full restoration of articular cartilage was not obtained at all sites of the knee joint within the 15 weeks of remobilization. Immobilization of the skeletally immature joint therefore may affect the development of articular cartilage in such a way that very slow recovery or permanent alterations are induced.
Site‐specific cartilage changes in murine degenerative knee joint disease induced by iodoacetate and collagenase
Authors: Van Osch G. J. V. M. , Van Der Kraan P. M. , Van Den Berg W. B. 
Published: February 2005

AbstractDegenerative joint disease was induced in the knee joints of mice by intraarticular injection of two different stimuli: iodoacetate and highly purified collagenase. Proteoglycan synthesis was measured in vivo at different time points in four topographical areas of the knee joint (central and peripheral parts of the patella and central parts of the medial and lateral tibial plateaus) and was compared with histological observations of localized damage to the joint. In vitro incubation with iodoacetate had a direct effect on proteoglycan metabolism. Intra‐articular injection of iodoacetate in vivo inhibited the proteoglycan synthesis in cartilage from the central part of the patella. In the peripheral part of the patella, inhibition on day 1 was followed by stimulation of synthesis on days 3–30. Proteoglycan synthesis also was inhibited in the central parts of the medial and lateral tibial plateaus. The areas with inhibited synthesis had loss of safranin O staining on histology. In vitro incubation with collagenase did not have a direct effect on the proteoglycan metabolism of intact cartilage; this led to the assumption that osteoarthritis after injection of collagenase is caused by ligamentous injury, which leads to an unstable joint. Injection of collagenase in vivo stimulated the proteoglycan synthesis in cartilage from the central and peripheral parts of the patella. In an early stage of the process, the cartilage from the tibial plateaus also was slightly stimulated. From 30 days after injection of collagenase, synthesis in the lateral tibial plateau decreased, whereas synthesis in the patella remained stimulated and synthesis in the medial tibial plateau remained normal. On histology, cartilage from the patella and the medial tibial plateau had a normal appearance, and there was loss of cartilage from the lateral tibial plateau. Our data indicate that the variation in response of cartilage from different anatomical areas of the knee joint depends on the stimulus used. This suggests that the location of cartilage damage depends on the etiological factor responsible for induction of the osteoarthritic process.
Radial tie fibers influence the tensile properties of the bovine medial meniscus
Authors: Skaggs D. L. , Warden W. H. , Mow V. C. 
Published: February 2005

AbstractAlthough collagen fibers are arranged predominantly in the circumferential direction in the knee meniscus, there is evidence for radially oriented fibers within human menisci. A bovine medial meniscus model was used to study the hypothesis that radial fibers alter the radial tensile properties of the meniscus. The architecture of the collagen network and tensile properties of the bovine medial meniscus were examined; attention was given to large “radial tie fibers” and their regional variation. Menisci were sectioned serially into slices 400 μm thick. Polarized light microscopy showed that the distribution of radial tie fibers varied greatly among the anterior, central, and posterior regions. These radial tie fibers were larger and more frequent in the posterior region. Radial fibers persisted over many adjacent sections with similar architecture, which led to our hypothesis that they may be arranged in continuous sheets in which the morphology varies by region. Radially oriented specimens for tensile testing were grouped according to the number of radial tie fibers (full, partial, and no fiber) and region (anterior, central, and posterior). Uniaxial tensile testing was performed on a testing machine at a strain rate of 0.00017 sec−1 until failure. The tensile modulus, ultimate tensile stress, and ultimate tensile strain were determined. The presence of radial tie fibers in the specimen had a significant effect on the tensile modulus and ultimate tensile stress. Specimens containing full radial tie fibers were stiffest and failed at the lowest strains; in specimens from the posterior region, the tensile modulus was 392%, the ultimate tensile stress was 314%, and the ultimate tensile strain was 68% that of the specimens with no radial fibers. In no‐fiber specimens, the tensile modulus in the posterior region was 225% of the modulus in the anterior region, and the ultimate tensile strain in the posterior region was 68% that of the strain in the anterior region. The abundance of radial tie fibers in the posterior region seems to contribute to the increased stiffness of this region. The preferential stiffening of the posterior region by these radial fibrous sheets may be well suited to the manner in which the bovine medial meniscus functions in load‐bearing.
Kinematics of the normal trapeziometacarpal joint
Authors: Imaeda Toshihiko , Niebur Glen , Cooney William P. , Linscheid Ronald L. , An Kai‐Nan 
Published: February 2005

AbstractMotion of the trapeziometacarpal joint was studied in 12 hands from fresh human cadavera. By use of a magnetic tracking system, a full range of motion of the first metacarpal was analyzed with respect to a defined trapezial coordinate system. The traces of the reference points on the head and base of the first metacarpal were monitored, and the instantaneous centers of rotation were calculated. During circumduction, the reference points on the head and base followed elliptical paths but in opposite directions. The average instantaneous center of circumduction was at approximately the center of the trapezial joint surface. In flexion‐extension, the axis of rotation was located within the trapezium, and the path of the head was identical to the path of the base. In abduction‐adduction, the axis of rotation was located distal to the trapezium within the base of the first metacarpal, and the base and head moved in opposite directions. There was no single center of rotation: rather, instantaneous motion occurred reciprocally between these centers of rotation within the trapezium and metacarpal base in the normal thumb. This changing instantaneous center of rotation results in a unique pattern of motion which is related to congruent, tightly constrained joint surfaces of two reciprocal saddle joints and to precisely positioned extraarticular ligaments.
Osteoarthritis in cynomolgus macaques: A primate model of naturally occurring disease
Authors: Carlson Cathy S. , Loeser Richard F. , Jayo Manuel J. , Weaver David S. , Adams Michael R. , Jerome Christopher P. 
Published: February 2005

AbstractThe objective of the present study was to determine if naturally occurring osteoarthritis of the knee joints that is similar to the condition in humans develops in cynomolgus macaques. Knee joints from 58 young adult (mean age, 7.4 years) female cynomolgus macaques were studies with x‐ray densitometry, high‐detail radiography, and histology. The animals studied were subjects in a triad designed to examine the effects of the administration of sex steroids on atherosclerosis; except for a control group, the monkeys had been either ovariectomized or treated with sex steroids for 2 years. Therefore, the data were analyzed to determine if these treatments, both of which can influence bone density, affected the severity of osteoarthritis. There was a high prevalence of osteoarthritic lesions, morphologically similar to those seen in humans. Bone changes were more common and severe than cartilage changes and morphologically appeared to precede the cartilage changes. Treatment with testosterone resulted in increased body weight, body mass index, and bone mineral content in the femur and tibia but did not affect the severity of osteoarthritis. These data indicate that naturally occurring osteoarthritis developed in the knee joints of cynomolgus macaques; these animals may be a useful model for the study of osteoarthritis in humans.
Healing of the rabbit medial collateral ligament following an o'donoghue triad injury: Effects of anterior cruciate ligament reconstruction
Authors: Engle Carolyn P. , Noguchi Masahiko , Ohland Karen J. , Shelley Franz J. , L‐Y. Woo Savio 
Published: February 2005

AbstractThe effects of healing time and anterior cruciate ligament reconstruction on healing of the medial collateral ligament and stability of the knee joint were evaluated in a rabbit model of an O'Donoghue triad injury (rupture of the medial collateral ligament with removal of the anterior cruciate ligament and part of the medial meniscus). At time 0 and at 6 and 12 weeks postoperatively, the anterior‐posterior translation and varus‐valgus rotation of the knee, the structural properties of the femur‐medial collateral ligament‐tibia complex, and the mechanical properties of the substance of the medial collateral ligament were evaluated. Although anterior‐posterior translation increased significantly with time, we could not demonstrate a significant temporal effect on varus‐valgus rotation. The ultimate load, elongation at failure, and energy absorbed to failure improved with time. In addition, with time, failure of the complex occurred more often in the ligament substance than at the osseous insertion. Because healing time did not affect the cross‐sectional area or modulus of the medial collateral ligament, the improved structural properties of the complex resulted not from improvements in the mechanical properties of the tissue but rather from healing of the tibial insertion site. By 12 weeks, the reconstructed knees had only minor signs of osteoarthrosis on the tibiofemoral surfaces; this is in contrast to the findings in anterior cruciate ligament‐deficient knees in our earlier study. Initially, reconstruction also improved stability of the knee. Additionally, at 12 weeks, the stiffness of the complexes from the reconstructed group was 1.3 times that of the anterior cruciate ligament‐deficient group (p < 0.05), and the ultimate load had increased by a factor of 1.6 (p < 0.05). Our findings demonstrate that reconstruction of the anterior cruciate ligament in the rabbit helps to stabilize the joint, improves healing of the medial collateral ligament, and may decrease the incidence of early‐onset osteoarthrosis after an O'Donoghue triad injury.
Mechanical Properties of Canine Articular Cartilage Are Significantly Altered Following Transection of the Anterior Cruciate Ligament
Authors: Setton L. A. , Mow V. C. , Müller F. J. , Pita J. C. , Howell D. S. 
Published: February 2005

AbstractThe compressive, tensile, and swelling properties of articular cartilage were studied at two time periods following transection of the anterior cruciate ligament in the knee of greyhound dogs. An experimental protocol was designed to quantify the essential equilibrium and biphasic material properties of cartilage in tension, compression, and shear, as well as the parameters of isometric swelling behavior. All properties were measured at several sites to elicit differences between sites of frequent and less frequent contact. Hydration was determined at each site and was compared with the material properties of cartilage from corresponding sites. There were extensive changes in all compressive, tensile, and swelling properties of cartilage after transection of the anterior cruciate ligament. Twelve weeks after surgery, the intrinsic moduli were reduced significantly in compression (approximately 24% of control values), tension (approximately 64%), and shear (approximately 24%), and the hydraulic permeability was elevated significantly (approximately 48%). Significant increases in hydration (approximately 9%) also were observed, as well as a strong correlation of hydration with hydraulic permeability. The pattern of these changes was not found to differ with site in the joint, but significant differences were observed in the magnitude of change for cartilage from the femoral groove and the femoral condyle. The pattern and extent of changes in the material properties following transection of the anterior cruciate ligament indicate that altered loading of the joint severely compromises the overall mechanical behavior of articular cartilage. The observed loss of matrix stiffness in compression, tension, and shear is associated with increases in the deformation of the solid matrix, a diminished ability to resist swelling, and the increase in hydration observed in this study. The increased swelling and elevated water content were related directly to the increase inhydraulic permeability; this suggests an associated loss of fluid pressurization as the load support mechanism in the degenerated cartilage. Without a successful mechanism for repair, damage to the solid matrix may progress and lead to further degenerative changes in the biochemistry, morphology, and mechanical behavior of articular cartilage.
Diurnal fluid changes of lumbar discs measured indirectly by magnetic resonance imaging
Authors: Paajanen Hannu , Lehto Ilkka , Alanen Anu , Erkintalo Minna , Komu Markku 
Published: February 2005

AbstractThe feasibility of magnetic resonance imaging and the magnetization transfer technique for measurement of diurnal fluid changes in lumbar discs was studied with the use of 13 healthy subjects. The diurnal height loss of the subjects ranged from 13 to 21 mm. The disc signal in T2‐weighted magnetic resonance imaging increased as much as 25% after overnight bed rest, presumably due to the enhanced influx of water. The change in magnetization transfer parameters also suggested increased hydration of the disc after bed rest. Magnetic resonance imaging techniques can be used for indirect measurement of the changes in fluid content and the interaction of water with macromolecules in the disc.