bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variation of collagen fiber alignment in a joint surface: A scanning electron microscope study of the tibial plateau in dog, rabbit, and man
Authors: Clark John M. 
Published: February 2005

AbstractTo determine if articular cartilage collagen fiber organization differs with location on the tibial plateau, specimens from dogs, humans, and rabbits were studied by scanning electron microscopy. Joint surfaces were fixed, dehydrated, and fractured radially so that the periphery could be compared with the center on single specimens. Generally, fibers were more tightly packed in the lateral side than in the medial and in the periphery as compared with the center, where the cartilage was consistently thicker and the radial zone was dominant and composed of straight vertical fibers. In the periphery, the tangential and transitional zones were better developed and contributed up to 50% of the cartilage depth in comparison to only 5% centrally. The soft, dull, malacic appearance of the center results from lack of a true surface layer of tangential collagen fibers.
Physeal reconstruction using tissue donated from early postnatal limbs in a murine model
Authors: Cundy Peter J. , Jofe Michael , Zaleske David J. , Ehrlich Michael G. , Mankin Henry J. 
Published: February 2005

AbstractPhyseal reconstruction was performed in a murine model by transplanting corresponding postanatal tissue from 4‐day‐old C57B mice to resection defects. The site of the reconstruction, the murine distal femoral epiphysis, is completely cartilaginous and avascular at this stage of development. The tissue transplanted into the defect was demonstrated to have high kinetic activity by its incorporation of titriated thymidine. The physeal reconstruction as performed restored only 25% of normal growth. While transplanting cell populations is feasible, the method will require a great deal of work before clinical application.
The influence of ibuprofen on fracture repair: Biomechanical, biochemical, histologic, and histomorphometric parameters in rats
Authors: Huo Michael H. , Troiano Nancy W. , Pelker Richard R. , Gundberg Caren M. , Friedlaender Gary E. 
Published: February 2005

AbstractIbuprofen is a widely used cyclo‐oxygenase inhibitor in clinical practice. It has been demonstrated by others to have an inhibitory effect on fracture repair in animals. In the present study, we were unable to demonstrate any significant alterations in fracture biomechanics as measured by torsion testing and fracture stage in mature Sprague‐Dawley rats treated with 30 mg/kg/day oral dose of ibuprofen, starting 3 days following fracture, over a 12‐week time interval. Fracture histology and serum osteocalcin levels were no different in treated animals than control animals. Furthermore, histomorphometric parameters of bone remodeling, including bone volume and bone formation rate in the intact tail vertebrae of these animals with unilateral femur fractures, were no different between treated and control animals.
Synthesis and characterization of magnetically responsive albumin microspheres containing cis‐hydroxyproline for scar inhibition
Authors: Iannotti J. P. , Baradet T. C. , Tobin M. , Alavi A. , Staum M. 
Published: February 2005

AbstractMagnetically responsive albumin microspheres containing the proline analog, cis‐hydroxyproline, were synthesized and their in‐vitro physical properties were characterized. These microspheres have an average size of 1.1 ± 0.3 pm with 94% of the microspheres <2.0 pm. They are uniformly spherical and contain 67% albumin, 22% magnetite, and 8% cis‐hydroxyproline. The cis‐hydroxyproline is releasable during a 72‐h period and demonstrates a slow, releasable pool that constitutes approximately 50% of the incorporated drug. cis‐Hydroxyproline is neither chemically nor biologically altered during its incorporation into the microsphere. cis‐Hydroxyproline release from microspheres results in the in vitro inhibition of collagen secretion, which is indistinguishable from unincorporated cis‐hydroxyproline. In a rat‐tail animal model these microspheres were selectively targeted using an external magnetic field applied to a 1.5–2.0‐cm target site. Fifty to 80% of the infused microspheres were localized to this site, whereas without a magnetic field only 15–20% of the microspheres are localized to this site. cis‐Hydroxyproline microspheres resulted in a 16% decrease in collagen content in a scar model when compared with untreated animals (p < 0.05). With further refinement of this method of drug delivery, clinically useful inhibition of scar formation may result.
Culture‐expanded human periosteal‐derived cells exhibit osteochondral potential in vivo
Authors: Nakahara Haruhiko , Goldberg Victor M. , Caplan Arnold I. 
Published: February 2005

AbstractPeriosteal cells were enzymatically liberated from human rib periostea obtained from autopsies of 37 donors with an age distribution ranging from 25 weeks of gestation to 88 years old. These cells were introduced into cell culture and subcultured when they reached confluence. After subculture, the adherent periosteal‐derived cells showed a nondescript, fibroblast‐like morphology in cell culture. The cells from various passages of each donor were tested for in vivo osteochondrogenic potential with three different assay methods in athymic mice: (a) inoculation assay—the cells were directly inoculated into a subcutaneous site, (b) porous ceramics assay—the cells were combined with porous calcium phosphate ceramics, and this composite graft was implanted into a subcutaneous site, and (c) diffusion chamber assay—the cells were loaded into diffusion chambers and cultured in the peritoneal cavity. Frozen‐preserved and recultured periosteal‐derived cells were also assayed in the same way. In cases of donors younger than 19 years old, cultured, periosteal‐derived cells from up to several passages consistently formed bone and/or cartilage in each of the three assays. Frozen‐preserved and recultured cells from these donors also formed bone and/or cartilage after introduction into the three in vivo assays. In cases of donors older than 22 years of age, cultured, periosteal‐derived cells formed neither bone nor cartilage in vivo. Cultured muscle fibroblasts from some of the same donors did not form bone or cartilage when assayed in vivo under identical conditions. These results suggest that periosteal cells with osteochondrogenic potentials can be liberated from the periosteum of a rib of human donors up to a certain age. Importantly, this potential is retained after enzymatic liberation, cell culture, subculturing, and freeze preservation. The present results suggest that culture‐expanded human periosteal‐derived cells from young donors may be useful in the repair of skeletal defects to foster cell‐mediated regeneration of skeletal tissues, and that this methodology can be used to elucidate cellular, molecular, and genetic disorders in various metabolic bone diseases and skeletal dysplasias.
Localization of type X collagen in canine growth plate and adult canine articular cartilage
Authors: Gannon James M. , Walker Gordon , Fischer Mark , Carpenter Randy , Thompson Roby C. , Oegema Theodore R. 
Published: February 2005

AbstractType X collagen was extracted from ends of canine growth plates by pepsin digestion after 4 M guanidine hydrochloride extraction, purified by stepwise salt precipitation (2.0 M NaCl in 0.5 M acetic acid), and chromatographed on a Bio‐Gel A1.5 M column in 1.0 MCaCl2. Without reduction on sodium dodecyl sulfate (SDS) polyacrylamide gels, the preparation yielded a single, high‐molecular‐weight (mol wt) band; after reduction, a single band of relative mol wt 5.0 × 104 was found. Polyclonal sera were raised against the purified collagen and used in the immunolocalization of canine type X collagen. As expected, indirect immunoperoxidase (IP) or indirect immunofluorescent staining with the polyclonal sera demonstrated that most of the immunoreactivity was localized in the zone of provisional calcification of the growth plate and in cartilage remnants in the metaphyseal region of the physis. A progressive decrease in staining toward the diaphysis of the fetal canine long bone was apparent as the trabecular structures were remodeled to bone. Unexpectedly, type X collagen was also detected in the zone of calcified, mature articular cartilage. It was concentrated in the pericellular matrix of the chondrocytes, appeared at or just above the tidemark, and was expressed immediately before mineralization. Identification of type X collagen in both the canine growth plate and the zone of calcified articular cartilage suggests that cells in the deep layer of cartilage and in the zone of calcified cartilage in the adult animal retain some characteristics of a growth plate and may be involved in regulation of mineralization at this critical interface. The expression of growth plate‐like properties would allow the deep chondrocytes of mature articular cartilage to play a role in remodeling of the joint with age and in the pathogenesis of osteoarthritis.
Recombinant human insulin‐like growth factor‐I stimulates in vitro matrix synthesis and cell proliferation in rabbit flexor tendon
Authors: Abrahamsson Sven‐Olof , Lundborg Göran , Lohmander L. Stefan 
Published: February 2005

AbstractFlexor tendons have an intrinsic ability for repair, with a capacity to metabolize matrix components and to proliferate. To identify factors with the potential of affecting those abilities, the effects of recombinant human insulinlike growth factor (rhIGF‐I), insulin and fetal calf serum (FCS) on the synthesis of proteoglycan, collagen, and non‐collagen protein and cell proliferation were investigated in short‐term explant cultures of the deep flexor tendon of the rabbit. Matrix synthesis and cell proliferation were stimulated dose dependently by rhIGF‐I at doses between 10 and 250 and at 10‐100 ng/ml, respectively, by insulin at 250–5,000 ng/ml, and by FCS at 2–15%. Estimated maximal stimulation (Emax) of up to three times the control value was observed with rhIGF‐I at 250 ng/ml. Maximal stimulation was observed at 5,000 ng/ml with insulin, and FCS at 15%. rhIGF‐I was more potent than insulin in stimulating protein synthesis and cell proliferation. The Emax of stimulation of proteoglycan and collagen synthesis by rhIGF‐I were two times that of FCS, and the Emax of cell proliferation by FCS was twice that of rhIGF‐I. Growth factors thus have the ability to stimulate matrix synthesis and cell proliferation in rabbit flexor tendon. This provides a rationale for further studies on the role of growth factors in flexor tendon healing in humans.
Effects of osteochondral defect size on cartilage contact stress
Authors: Brown Thomas D. , Pope David F. , Hale Joseph E. , Buckwalter Joseph A. , Brand Richard A. 
Published: February 2005

AbstractContact stress distributions were studied in vitro for 13 dog knees, with full‐thickness osteochondral defects drilled in the weight‐bearing area of both femoral condyles. Diameters of the circular defects were concentrically enlarged from 1 to 7 mm. Digitally‐imaged Fuji film was used to record cartilage contact stress distribution on femoral condyles for each increment of defect diameter. All specimens showed at least some tendency for contact stress concentration at the rim of the defects. However, detailed distributions had large interspecimen variability and, within a given specimen, contact stress distributions became progressively more nonuniform around the defect rim as the diameter was enlarged. Averaged over the full series of 26 condyles, circumferential mean cartilage contact stress around the defect rim was only moderately higher (by 10–30%) than intact surface's peak local contact stress [series average = 6.2 mega pascals (MPa)]. Maximal rim stress concentration occurred for 2 mm defects, there being a consistent trend toward mild rim stress decrease with further defect enlargement. Such modest contact stress elevations, per se, are probably insufficient to inhibit defect repair or to cause degeneration of surrounding cartilage. However, near the defect rim (for all diameters), the radial component of the gradient of contact stress (i.e., radialdirection variation of contact stress) was consistently elevated by an order of magnitude above that for intact, condyle articular cartilage.
Pattern of bone loss of the proximal femur: A radiologic, densitometric, and histomorphometric study
Authors: Kawashima Tadashi , Uhthoff Hans K. 
Published: February 2005

AbstractThe pattern of bone loss in the proximal femur was studied in 141 cadaveric femora from 36 women and 39 men ranging from 27 to 89 years of age. Bone mineral density (BMD) of the femoral neck, greater trochanter, Ward's triangle, and tensile and compressive stress regions were measured by dual photon absorptiometry. Radiographs were graded by Singh's method. Histomorphometry of tensile and compressive trabecular areas was performed on ground midsection of the methylmethacrylate‐embedded whole proximal femur. Although Singh index had some correlation with BMD of the femoral neck, the various BMD measurements showed that all regions lost bone to the same extent; in particular, no selective bone loss was found at low stress regions (tensile trabeculae or Ward's triangle). Histomorphometry revealed that most of the trabecular bone loss of the proximal femur is attributable to a decrease in thickness of individual trabeculae.
Mesenchymal stem cells
Authors: Caplan Arnold I. 
Published: February 2005

AbstractBone and cartilage formation in the embryo and repair and turnover in the adult involve the progeny of a small number of cells called mesenchymal stem cells. These cells divide, and their progeny become committed to a specific and distinctive phenotypic pathway, a lineage with discrete steps and, finally, end‐stage cells involved with fabrication of a unique tissue type, e.g., cartilage or bone. Local cuing (extrinsic factors) and the genomic potential (intrinsic factors) interact at each lineage step to control the rate and characteristic phenotype of the cells in the emerging tissue. The study of these mesenchymal stem cells, whether isolated from embryos or adults, provides the basis for the emergence of a new therapeutic technology of self‐cell repair. The isolation, mitotic expansion, and site‐directed delivery of autologous stem cells can govern the rapid and specific repair of skeletal tissues.
The effects of frequency and duration of controlled passive mobilization on tendon healing
Authors: Takai Shinro , Woo Savio L‐Y. , Horibe Shuji , Tung David K‐L. , Gelberman Richard H. 
Published: February 2005

AbstractThis study was designed to determine the effects of frequency and duration of controlled passive motion on the healing flexor tendon following primary repair. Adult mongrel dogs were divided into two groups based on frequency of controlled passive motion. In one group, motion was applied manually at a frequency of 12 cycles/min for 5 min/day; in the other group, a continuous passive motion machine was used to apply motion at a lower frequency of 1 cycle/min for 60 min/day, making the number of cycles each day for both groups identical. Gliding function and tensile properties of repaired tendons were evaluated biomechanically at 3 and 6 weeks postoperatively. Results showed that gliding function in both groups was similar, but tensile properties, as represented by linear slope, ultimate load, and energy absorption, were significantly improved in the higher frequency group. It was concluded that frequency of controlled passive motion rehabilitation is a significant factor in accelerating the healing response following tendon repair, and higher frequency‐controlled passive motion has a beneficial effect.
Effects of propranolol on bone metabolism in the rat
Authors: Minkowitz Barbara , Boskey Adele L. , Lane Joseph M. , Pearlman Hubert S. , Vigorita Vincent J. 
Published: February 2005

AbstractPropranolol, a nonspecific β‐blocker, has many physiologic effects. Its effects on bone in vivo are unknown, although β receptor sites have been found on osteoblasts. In this study, the hypothesis tested was that low doses of propranolol could alter bone properties and enhance orthotopic endochondral bone formation. In a group of nonsurgical rats, propranolol treatment increased formation. In a group of nonsurgical rats, propranolol treatment increased femoral torsional strength on biomechanical testing. In the rat surgical model used, right femora were fixed to a polyethylene plate and then defects were created mid‐diaphysis and subsequently filled with demineralized bone matrix. These rats (defect rats) were randomly divided into groups that were given propranolol or a saline carrier for 19 consecutive days. In the defect rats, increased trabecular femoral metaphyseal mineral apposition rates were observed in propranolol‐treated groups. Densitometry and roentgenographic scoring of callus formation after 12 weeks in propranolol‐treated rats revealed increased callus and bone union. The results of this study indicate that propranolol treatment can significantly affect bone properties.
Telopeptide‐depleted bovine skin collagen as a carrier for bone morphogenetic protein
Authors: Takaoka Kunio , Koezuka Masahiro , Nakahara Haruhiko 
Published: February 2005

AbstractThe telopeptide of type I collagen is thought to be responsible for causing immunogenic response when introduced into xenogenic hosts. To eliminate this problem, solubilized bovine skin collagen was filtered through a millipore membrane, digested repeatedly with pepsin to remove telopeptides, and used as a carrier for a water‐soluble, partially‐purified fraction of bone morphogenetic protein (BMP) in mice. Composite implants of this telopeptide‐depleted collagen and the partially‐purified BMP fraction consistently elicited ectopic bone formation in mice 3 weeks postimplantation. When implanted alone, collagen or BMP failed to show this response. Collagens, prepared by use of conventional methods (acid‐solubilized collagen, or collagen‐digested once with pepsin) were also assessed as carriers for BMP, but were found to be inferior in terms of consistency of bone formation and amount of induced bone mass. The results suggest that telopeptide‐depleted collagen permitted a gradual release of purified BMP for induction of bone, with minimal immunogenic interference. Consequently, this collagen carrier represents an important development for future clinical application of BMP.
Fibronectin and keratan sulfate synthesis by canine articular chondrocytes in culture is modulated by dibutyryl cyclic adenosine monophosphate
Authors: Leipold Harry R. , Wurster Nancy Burton , Steinmeyer Juergen , Vernier‐Singer Margaret S. , Lust George 
Published: February 2005

AbstractThe ability of cyclic adenosine monophosphate (cAMP) to maintain differentiated properties of canine articular chondrocytes in culture is reported. Treatment with 0.5 mM dibutyryl cAMP (DBcAMP) caused the cells to adopt a more rounded morphology. This change in morphology seems to have no effect on the overall biosynthetic rates of the cells. After a pulse with 35S‐methionine, there was no difference in the concentration of labeled proteins between cultures treated with DBcAMP and control cultures. After 6 days, the amount of fibronectin (FN) in the media of DBcAMP‐treated cultures detected by an enzyme‐linked immunosorbent assay was specifically reduced by 30%. The amount of 35S‐FN purified by gelatin‐affinity chromatography decreased 33%. Moreover, the percentage of FN containing the extra domain A sequence was reduced from 19.4 ± 8.7% in control cultures to 9.6 ± 4.2%. Concomitant with the decrease in FN, there was an increase in the concentration of keratan sulfate in the media of DBcAMP‐treated cultures. After 6 days, treated cultures had 47% more keratan sulfate than controls did. These changes appear not to be the result of a change in the deposition of FN or keratan sulfate, because the amount of these molecules that could be extracted from the cell layer was typically below the limit of detection of the assays. Instead, it seems there is a phenotypic change in the chondrocytes pertaining to the production of FN and keratan sulfate.
Human growth plate development in the fetal and neonatal period
Authors: Rodriguez Jose I. , Razquin Socorro , Palacios Jose , Rubio Vicente 
Published: February 2005

AbstractThe development of the normal human upper tibial growth plate was studied at autopsy in 46 stillborns and 79 newborns of 20–41 weeks gestational age. During this time period, the histology of this plate evolves from a highly cellular structure with relatively poor columnar organization and matrix development to the well known structure seen later in postnatal life. The thickness of the growth plate, assessed in the area surrounding the longitudinal tibial axis, decreases continuously from 1.15 mm on the 20th week to 0.6 mm on the 38th week. This decrease results from losses of both matrix and cellular components, mostly of the latter. However, the relative fraction of area occupied by the matrix significantly increased (12%) and matrix area per cell increased 1.5 times over the last half of gestation, indicating a maturation process of the plate towards a more matrix‐oriented structure with age. In this maturation process the number of cells per unit area does not change and the average size of the cells appears to decrease. Plate thickness does not decrease further in the final 3 weeks of pregnancy and increases in early neonatal life; this has no apparent influence on the tibial growth rate. In the period under study the relative anatomical participation of the upper tibial growth plate decreases from ∼4% of the radiographic length of the tibia on the 20th week to < 1% at term. Present data will provide fetal and neonatal growth plate standards needed to obtain a better understanding of this structure during both normal and abnormal conditions.
Antagonist drugs and bone vascular smooth muscle
Authors: Dean Michael T. , Wood Michael B. , Vanhoutte Paul M. 
Published: February 2005

AbstractAn ex vivo canine tibia model was used to quantitate the specific adrenergic subtype contribution in bone vasculature. Tibiae were obtained from mongrel dogs, the nutrient artery was catheterized, and the bone was placed in an ex vivo perfusion apparatus at constant flow. Perfusion was accomplished using oxygenated Krebs‐Ringer solution. A norepinephrine dose‐response curve was obtained by using incremental single bolus doses. Each bone was perfused with a vasoactive drug at a standard physiologic dosage. After 30 min of perfusion, a second norepinephrine dose‐response curve was generated. The degree of attenuation of the norepinephrine dose‐response curve, as determined by the total area under the curve, was interpreted as the relaxation effect of the drug on the smooth muscle of the vascular bed. Prazosin (α1‐receptor antagonist), rauwolszin (α2‐receptor antagonist), propranolol (β‐receptor antagonist), and diltiazem (calcium‐entry inhibitor) were evaluated. Our data suggest that α1 and α2 adrenergic receptor antagonism results in a quantitatively similar attenuation of norepinephrine‐induced vascular smooth muscle contraction. Calcium‐entry antagonism produced less, but significant, attenuation of smooth muscle contractility. Beta‐adrenergic receptor blockade yielded only a slight, although consistent, reduction in reactivity. Simple perfusion with Krebs‐Ringer solution had no effect.