bluuebunny/crossref_metadata_2025_split huggingface dataset:
Treatment with recombinant human macrophage colony‐stimulating factor resorbs blood clot and restores osteoclastogenesis in heterotopic bone induced by partially purified native bone morphogenetic protein in osteopetrotic (op/op) mice
Authors: Miyazawa Ken , Urist Marshall R. 
Published: February 2005

AbstractNative bone morphogenetic protein and associated noncollagenous proteins induced the formation of heterotopic bone in the hindquarter muscles of osteopetrotic (op/op) mice and those of their phenotypically normal littermates (+/?). In op/op mice, the heterotopic bone consisted of a disorganized, densely packed mixture of irregular calcified cartilage, osleoid, Chondro‐osteoid, and fibrous tissue. Injections of recombinant human macrophage colony‐stimulating factor initiated bone resorption that began in the peripheral vascularized regions of the metaphyses and continued in central areas of uncalficified avascular chondro‐osteoid. On vascularized surfaces, osteoclasts were stained with tartrate‐resistant acid phosphatase. In op/op mice treated with macrophage colony‐stimulating factor, the osteoclasts were small, with only two or three nuclei and they did not exhibit tartrate‐resistant acid phosphatase staining. In untreated op/op mice, surgical blood clots persisted in the heterotopic sites as late as 3 weeks after the operation, whereas in treated op/op mice, the blood clots were absorbed almost as rapidly as in normal mice. Histologically, recombinant human macrophage colony‐stimulating factor restored normal macrophage functions: absorption and organization of blood clot, osteoclastogenesis. synthesis of tartrate‐resistant acid phosphatase, bone remodeling, islands of myelopoiesis, and construction of an ossicle complete with a cortex and a medulla filled with functioning hematopoietic bone marrow.
Studies of ischemia‐reperfusion injury in skeletal muscle: Efficacy of 21‐aminosteroids on microcirculation and muscle contraction after an extended period of warm ischemia
Authors: Korompilias Anastasios V. , Chen Long‐En , Seaber Anthony V. , Urbaniak James R. 
Published: February 2005

AbstractThe present study was conducted to elucidate the effects of tirilazad mesylate (U‐74006F), a potent inhibitor of lipid peroxidation, on vessel diameter, capillary perfusion, and contractile function of rat cremaster muscle during a 90‐minute reperfusion period that followed 4 hours of warm ischemia. Two groups of 32 animals were treated with either 3 mg/kg U‐74006F or the vehicle (citrate buffer) alone 30 minutes before. ischemia, 90 minutes after ischemia, and immediately before reperfusion. With use of intravital videomicros‐copy, the internal luminal diameters of preselected vessels were measured prior to ischemia and during reperfusion The area that filled with fluorescein was determined at 15‐minute intervals for as long as 90 minutes of reperfusion, and contractile function was examined in vitro in an organ bath at that point. In the U‐74006F group, after 90 minutes of reperfusion the vessel diameters returned completely to baseline and the diameters of all three categories of vessels at every time point from 10 to 90 minutes of reperfusion had significantly more rapid recovery than the controls. Although some evidence of more rapid fluorescence was noted in the U‐74006F group, the two groups did not differ significantly at any time period of reperfusion. In response to tetanic stimulation, the muscles treated with U‐74006F had a significantly greater contractile force at all stimulation frequencies than the control musclss. Our findings indicate that pretreatment with U‐74006F can effectively decrease the rise of vascular resistance and preserve the contractile function of skeletal muscle during early reperfusion, thereby attenuating ischemia‐reperfusion injury.
Type‐II collagen gene expression is transiently upregulated in experimentally induced degeneration of rabbit intervertebral disc
Authors: Takaishi Hironari , Nemoto Osamu , Shiota Masanobu , Kikuchi Toshiyuki , Yamada Harumoto , Yamagishi Masaaki , Yabe Yutaka 
Published: February 2005

AbstractTo clarify phenotypic alterations of intervertebral disc cells during the repair process, we cloned partial type‐II collagen cDNA from rabbits and analyzed the level of expression of type‐II collagen mRNA in disc degeneration. An animal model was created by surgical denucleation of rabbit intervertebral discs through, an extraperitoneal approach. Eight animals each from an experimental and a control group were killed at 2, 4, 8, or 16 weeks postoperatively, and the disc samples were used for this study. Round chondrorcyte‐like cells that filled the herniated space showed intense signal of type‐II collagen mRNA and significant pericellular immunostaining of type‐II collagen but no clear staining of type‐I collagen. Northern. blot analysis revealed that the expression of type‐II collagen mRNA of the repair disc cells was transiently increased at 4 weeks postoperatively. The cells were able to change their morphology in response to mechanical stimulation by surgical denucleation and to induce a significant increase in the gene expression of type‐II collagen at an early phase of disc degeneration. The present results indicate the transient enhancement of repair activity in the degenerative process of injured fibrocartilage.
In vivo tensile behavior of a four‐bundle hamstring graft as a replacement for the anterior cruciate ligament
Authors: Wallace Michael P. , Howell Stephen M. , Hull M. L. 
Published: February 2005

AbstractThe purpose of this study was to measure the in vivo tensile behavior of a doublelooped semitendinosus and gracilis graft used to reconstruct a torn anterior cruciate ligament in the human knee. In 14 subjects, intraoperative tension was measured for each of the four graft bundles during passive motion from 0 to 90° of flexion. Two hypotheses were tested: (a) the peak tension carried by each of the four bundles was equal during passive motion, and (b) the mechanics of the bundles mimicked the functional bands of the wnative anterior cruciate ligament. The total tension was also calculated and used to determine strength requirements for fixation devices. The peak tensions of the four bundles during passive motion were not equal; however, enough tension was present in each bundle that load‐sharing occurred between bundles. The pattern of tension between the anterior and posterior bundles mimicked the reciprocating load‐sharing behavior of the functional bands of the native anterior cruciate ligament. Reciprocal tensile behavior was con sistently achieved with the use of a single femoral tunnel centered on the most isometric line without the need for two separate femoral sockets. The maximum total tension was 296 N; this was nearly equal to the strength of one commonly used fixation device.
Characterization of human bone marrow stromal cells with respect to osteoblastic differentiation
Authors: Majors Alana K. , Boehm Cynthia A , Nitto Hironori , Midura Ronald J. , Muschler George F. 
Published: February 2005

AbstractHuman bone marrow was harvested by means of iliac crest aspiration and cultured under conditions that promote an osteoblastic phenotype. Human bone marrow aspirates from 30 normal subjects, ages 8–80 years, with no systemic illness, yielded a mean of 92 ± 65 × 106 nucleated cells per 2 ml of aspirate. The prevalence of potential osteoblastic progenitors was estimated by counting the number of alkaline phosphatase‐positive colonies. This assay demonstrated a mean of 43 ± 28 alkaline phosphatase‐positive colonies per 106 nucleated cells, which was about one per 23,000 nucleated cells. The prevalence of these colonies was positively correlated with the concentration of nucleated cells in the original aspirate (p = 0.014) and was negatively correlated with donor age (p = 0.020). The population of alkaline phosphatase‐positive colonies in this model sequentially exhibited markers of the osteoblastic phenotype; essentially all colonies (more than 99%) stained positively for alkaline phosphatase on day 9. Matrix mineralization, which was associated with the synthesis of bone sialoprotein, was demonstrated on day 17 with alizarin red S staining. On day 45, cells that were stimulated with 1,25‐dihydroxyvitamin D3 synthesized and secreted osteocalcin at concentrations consistent with known osteoblastic cell lines. This model provides a useful method for the assay of progenitors of connective tissue from human subjects, examination of the effects of aging and selected disease states on this progenitor population, and investigation into the regulation of human osteoblastic differentiation.
Sustained proliferation accompanies distraction osteogenesis in the rat
Authors: Aronson J. , Shen X. C. , Gao G. G. , Miller F. , Quattlebaum T. , Skinner R. A. , Badger T. M. , Lumpkin C. K. 
Published: February 2005

AbstractThese studies were conducted to compare the local cellular proliferation patterns in the rat tibia during distraction osteogenesis with those during nondistracted fracture healing. Bone specimens from distraction osteogenesis and nondistracted fracture groups were analyzed 2, 10, and 20 days after surgery. Proliferation was determined by metabolic labeling with [3H]thymidine and by immunocytochemistry with an antibody to proliferating cell nuclear antigen. Videomicroscopy was used to count the cells staining positively within specified regions. The number of cells incorporating [3H]thymidine was positively correlated (r2 = 0.78) with the number of proliferating cell nuclear antigen positive cells on alternating serial slides. At day 2, the latter cells were largely confined to the bone marrow and periosteum in both groups, and the cell numbers per mm2 were also equivalent. At days 10 and 20, the proliferating cell nuclear antigen positive cells predominated in both the proximal and distal primary matrix front zones in the distraction osteogenesis group. In contrast, the proliferating cell nuclear antigen positive cells in the nondistracted fracture group were scattered throughout the healing area. Significantly more of these cells were in the primary matrix front zones than in any location within the nondistracted fracture‐healing area. The number of these cells in the bone marrow adjacent to the surgical area declined from day 2 to day 10 in both groups. The results suggest that (a) proliferating cell nuclear antigen immunostaining is a reliable indicator of cycling cells; (b) by day 10, distraction osteogenesis is characterized by a zone‐specific pattern of proliferating cells; and (c) distraction osteogenesis prolongs the stimulation of proliferation within the gap after fracture.
Proprioception after an acute knee ligament injury: A longitudinal study on 16 consecutive patients
Authors: Fridén Thomas , Roberts David , Zätterström Rose , Lindstrand Anders , Moritz Ulrich 
Published: February 2005

AbstractA defect in proprioception has been found in selected patient groups that have an anterior cruciate ligament deficient knee at different times after the original injury. The time of development and the extent of such defects were studied ongitudinally on 16 consecutive patients. During the first year after a primary knee injury, which included a complete rupture of the anterior cruciate ligament, we repeatedly performed three tests of proprioception: (a) one to determine the threshold for detecting a passive motion from starting positions of 20 and 40°, (b) an active reproduction of a passive angular change, and (c) a visual estimation of a passive angular change. The injured limb was compared with the uninjured limb and with the limbs of an age‐matched reference group of healthy subjects. The population did not have a normal distribution, and some patients had consistently extreme recordings in the threshold tests at the various times of testing. Significant differences were found between the groups at the starting position of 20°, when the injured knee was compared with the uninjured knee, after 1 month (p = 0.05), and after 2 months (p = 0.03). There was a trend toward a higher threshold for detecting a passive motion when the injured side was compared with the knees of the reference group at 1 month (p = 0.06) but not later on. A similar pattern was found for the injured knee at the starting position of 40°, but it was not significant. An impaired ability to detect a passive motion was registered for the nearly extended knee 1 and 2 months after a primary injury. In the active reproduction and visual estimation tests, no significant defects were found at any time during the first year in these consecutively studied patients.
Role of oxygen tension during cartilage formation by periosteum
Authors: O'Driscoll Shawn W. , Fitzsimmons James S. , Commisso Cinzia N. 
Published: February 2005

AbstractTissue engineering makes regeneration of cartilage possible but requires optimization of culture conditions. The effects of oxygen tension on cartilage metabolism are controversial in the literature, and we could find no information detailing the optimal oxygen concentration for growing new cartilage (neochondrogenesis). Periosteal cells and tissues can be used to grow cartilage in vivo and in vitro. In this study, using a standard periosteal organ culture model, we found that cartilage formation by periosteal explants is affected by the ambient oxygen concentrations. A total of 480 periosteal explants from 30 2‐month‐old New Zealand White rabbits were cultured in agarose suspension at different oxygen concentrations (1‐90%) for 6 weeks. Chondrogenesis, which was analyzed by histomorphometry and quantitative collagen typing, was maximal at 12–15% oxygen. There were no significant differences in chondrogenesis in the range of 12–45%. There was inhibition of cartilage and type II collagen formation at very high (90%) and very low (1–5%) oxygen concentrations. However, contrary to what some have thought, chondrogenesis is maximal under aerobic conditions. If this is true for systems other than periosteal implants, it would have important implications for growing cartilage in vitro.
Characterisation of human deltoid muscle in patients with impingement syndrome
Authors: Kronberg Margareta , Larsson Peter , Broström Lars‐Åke 
Published: February 2005

AbstractMuscle biopsies from the anterior and medial parts of the deltoid of 11 male patients and six male controls were analysed with morphological and immunohistochemical methods. The distribution, area, and capillarization of the muscle fibres were determined, and the amount of connective tissue was measured with staining for type‐III collagen. Compared with the controls, the patients with impingement syndrome had more type‐I than type‐II fibres, but the areas of the different types were almost the same. There was no difference in capillarization per fibre type between patients and controls, but the patients had more connective tissue. The results indicate that patients with impingement syndrome have morphological changes in the deltoid muscle, probably due to immobilisation and pain. They support the hypothesis that the deltoid muscle, the medial part in particular, is affected in patients with impingement syndrome.
Spatial and temporal expression of fibril‐forming minor collagen genes (types V and XI) during fracture healing
Authors: Yamazaki Masashi , Majeska Robert J. , Yoshioka Hidekatsu , Moriya Hideshige , Einhorn Thomas A. 
Published: February 2005

AbstractSkeletal development involves the coordinated participation of several types of collagen, including both major and minor fibrillar collagens. Although much is known about the major fibrillar collagens, such as types I and II, less is known about the minor fibrillar collagens, and their role in the repair and regeneration of bone has not been extensively studied. To clarify the role of minor fibrillar collagens in Fracture repair, we examined the spatial and temporal expression of mRNAs for pro‐α2(V) collagen and pro‐α1(XI) collagen in healing fractures in the rat by in situ hybridization and compared their patterns of expression with those Of mRNAs for pro‐α1(I) collagen, pro‐α1(II) collagen, and osteocalcin. A strong signal for pro‐α2(V) was detected in the periosteal osteoprogenitor cells, whereas osteocalcin mRNA was strongly expressed only in the deep layers of the hard callus. The distribution of the pro‐α2(V) signal was correlated with that of pro‐α1(I) but was mutually exclusive of that of pro‐α1(II).The expression of pro‐α1(Xl) mRNA was synchronously regulated with that of pro‐α1(II) during chondrogenesis in the soft callus. In the hard callus, pro‐α1(XI) signal Was found in osteoblastic cells at the site of intramembranous and endochondral ossification. These cells simultaneously expressed pro‐α2(V), although they were negative for pro‐α1(II). These findings suggest that the, α2(V) collagen chain participates in the formation of the noncartilaginous fibrillar network in the hard callus and preferentially contributes to the initial stage of the intramembranous bone formation. Recent reports have, revealed that type‐XI collagen, which had been classified as a cartilage‐type collagen, is not necessarily specific for cartilage. The present results advanced this recognition and demonstrated a coexpression of α1(XI) mRNA and α2(V) mRNA in the noncartilaginous tissues in the fracture callus; this suggests the presence of tissue‐specific and stage‐specific heterotrimers consisting of α1(XI) and α2(V) collagen chains and the association of such hybrid trimers with the major fibrillar collagens in the process of fracture healing.
Physiological and mechanical adaptations of rabbit medial collateral ligament after anterior cruciate ligament transection
Authors: Bray R. C. , Doschak M. R. , Gross T. S. , Zernicke R. F. 
Published: February 2005

AbstractProgressive physiological and mechanical changes in the medial collateral ligament of the adult rabbit were investigated for as long as 48 weeks after disruption of the anterior cruciate ligament. Eighty‐one New Zealand White rabbits were separated into experimental, sham‐operated control, and normal control groups. The experimental group underwent unilateral transection of the right anterior cruciate ligament, sham‐operated animals served as controls for comparison, and normal animals were evaluated as age‐matched, undisturbed (no surgery) controls. Blood flow to the medial collateral ligament (as a physiological measure) and mechanical function (structural and material properties) were assessed at 6, 14, and 48 weeks. The results indicated that loss of the anterior cruciate ligament leads to early mechanical deterioration of the medial collateral ligament with a corresponding loss of physiological homeostasis. Six to 14 weeks after the transection, values for cross‐sectional area of the medial collateral ligaments rapidly increased to 1.5 times control values. The ligament became twice as large as the control ligament by 48 weeks. Concomitantly, medial collateral ligament stress at failure of the medial collateral ligament complex decreased rapidly 6‐14 weeks after the transection and eventually fell to one‐half that of controls by 48 weeks. In terms of low‐load behaviour, laxity and load relaxation were significantly greater than that of controls 6 weeks after transection and were further increased by 14 weeks. By 48 weeks, laxity values had recovered somewhat and load‐relaxation measures had recovered to near control values. At both 6 and 14 weeks, a statistically significant elevation in blood flow was demonstrated compared with controls. By 48 weeks, however, blood flow was no different from that of the sham‐operated control. Thus, early after transection of the anterior cruciate ligament, both low‐load and high‐load mechanical properties of the medial collateral ligament deteriorated and the rate of blood flow was temporarily elevated. By 48 weeks, blood flow declined to near control values, with a corresponding recovery in viscoelastic behaviour. These findings suggest that, after transection of the anterior cruciate ligament, viscoelastic behaviour of the medial collateral ligament may be related to changes in blood flow and that restoration of normal flow patterns and vascular responses may be linked to tne recovery of some low‐load mechanical properties in the anterior cruciate ligament‐deficient medial collateral ligament.
Exercise of young thoroughbred horses increases impact strength of the third metacarpal bone
Authors: Reilly G. C. , Currey J. D. , Goodship A. E. 
Published: February 2005

AbstractExercise can have a profound effect on bone mass but little is known of its effect on bone's material properties. In this experiment, our hypothesis was that a large difference in the training regimen of young thoroughbreds would produce a measurable difference in the mechanical properties of their bone material. When they were about 19 months old, eight thoroughbred racehorses were given one of two exercise regimens that lasted for 19 weeks: four horses (controls) were walked for 40 minutes a day but had no other exercise, and the remaining four (exercised) were additionally trotted for 20 minutes a day and given progressively intensive exercise on a treadmill. Mechanical testing to failure was performed on longitudinal beam specimens of the mid‐diaphysis of the metacarpal. There was no difference in Young's modulus or bending strength between the two groups, although these properties varied somewhat depending on the position within the cortex from which the specimens had come. The specimensfrm the exercised horses had a slightly higher toughness, as measured by work (area under the load‐deformation curve). They had a considerably higher impact strength. The impact strength of specimens from, the outer coitex was also higher than that of those from the inner cortex in both groups. Impact strength correlated positively with the amount of micro‐cracking produced during testing. Microcracking is related to structural and microstructural features in the bone. Increased loading caused the bone to respond in a way lhat enhanced its ability to microcrack and hence its toughness.
Myoblast‐mediated gene transfer to the joint
Authors: Day Charles S. , Kasemkijwattana Channarong , Menetrey Jacques , Floyd S. Steven , Booth David , Moreland Morey S. , Fu Freddie H. , Huard Johnny 
Published: February 2005

AbstractSeveral genetic and acquired pathologic conditions of the musculoskeletal system, such as arthritis and damage to ligament, cartilage, and meniscus, may be amenable to gene therapy. Even though ex vivo gene transfer with synovial cells has been shown to deliver genes encoding for anti‐arthritic proteins into the rabbit knee joint, its success has been limited by a transient transgene expression, In this study, data were investigated regarding the use of muscle cells as an alternative gene‐delivery vehicle to the joint in newborn rabbit and adult severe combined immunodeficiency mice. We demonstrated that myoblasts were transduced more efficiently than synovial cells with use of the same adenoviral preparation in vitro. After intra‐articular injection, the engineered muscle cells adhered to several structures in the joint, including the ligament, capsule, and synovium. In addition, myoblasts fused to form many post‐mitotic myotubes and myofibers at different locations of the joint of the newborn rabbit 5 days after the injection. In the knee of the adult mouse, myoblasts fused and expressed the reporter gene for at least 35 days after the injection. The presence of post‐mitotic myofibers in the knee joint raises the possibility of long‐term expression of the secreted protein. Currently, numerous tissues in the joint (ligament, meniscus, and cartilage) have poor intrinsic healing capacity and frequently need surgical corrections. A stable gene‐delivery vehicle to the joint producing proteins that ameliorate these different musculoskeletal conditions may change the clinical implications of these pathologies.