bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of growth factors on matrix synthesis by ligament fibroblasts
Authors: Marui Takashi , Niyibizi Christopher , Georgescu Helga I. , Cao Min , Kavalkovich Karl W. , Levine Rebecca E. , Woo Savio L‐Y. 
Published: February 2005

AbstractAlthough it has been reported that several growth factors modulate soft‐tissue healing, the specific effects of growth factors on protein synthesis during ligament healing have not been widely investigated. In this study, we examined the effects of basic and acidic fibroblast growth factors, transforming growth factor β1, and epidermal growth factor on collagen and noncollagenous protein synthesis by cultured fibroblasts from medial collateral ligament and anterior cruciate ligament in vitro. Uptake of tritiated proline was used to measure synthesis of collagen and noncollagenous protein, and sodium dodecyl sulfate‐polyacrylamide gel electrophoresis was used to analyze the type of collagens synthesized. Our data showed that transforming growth factor β1 increased both collagen and noncollagenous protein synthesis by medial collateral and anterior cruciate ligament fibroblasts on a dose‐dependent basis. Collagen synthesis by cultured fibroblasts from the medial collateral and anterior cruciate ligaments was increased by treatment with transforming growth factor β1 by as much as approximately 1.5 times that of untreated controls. Although the response to transforming growth factor β1 by anterior cruciate ligament fibroblasts was equal to that by medial collateral ligament fibroblasts, the amounts of matrix proteins synthesized by anterior cruciate ligament fibroblasts were approximately half of that by medial collateral ligament fibroblasts. The increase was mostly in type‐I collagen. Treatment of anterior cruciate ligament fibroblasts with epidermal growth factor increased collagen synthesis by approximately 25% but had little effect on medial collateral ligament fibroblasts. Neither basic nor acidic fibroblast growth factor increased either collagen or noncollagenous protein synthesis. These findings suggest that topical application of transforming growth factor β1, alone or in combination with epidermal growth factor, may have the potential to strengthen the ligament by increasing matrix synthesis during its remodeling and healing processes.
Osteoarthritis: Differential expression of matrix metalloproteinase‐9 mRNA in nonfibrillated and fibrillated cartilage
Authors: Tsuchiya K. , Maloney W. J. , Vu T. , Hoffman A. R. , Huie P. , Sibley R. , Schurman D. J. , Smith R. L. 
Published: February 2005

AbstractExpression of matrix metalloproteinase‐9 mRNA in osteoarthritic and normal cartilage was analyzed using reverse transcription polymerase chain reaction and in situ hybridization. Fifty‐four osteoarthritic cartilage samples were obtained from 24 patients undergoing total knee arthroplasty. Sixteen normal cartilage samples were obtained from non‐osteoarthritic knees of four autopsy cases. With normal cartilage, reverse transcription‐polymerase chain reaction analysis for matrix metalloproteinase‐9 mRNA showed that chondrocytes exhibited only a trace signal. In analysis of osteoarthritic cartilage, chondrocytes of moderately and severely fibrillated cartilage exhibited a 73‐fold and 110‐fold increase in matrix metalloproteinase‐9 mRNA signal, respectively, relative to normal cartilage. Chondrocytes of nonfibrillated osteoarthritic cartilage exhibited a 6‐fold increase (p < 0.02) in matrix metalloproteinase‐9 mRNA signal relative to normal cartilage. Analysis of matrix metalloproteinase‐9 mRNA expression in fresh‐frozen sections of normal and osteoarthritic cartilage by in situ hybridization confirmed these results. This study showed that reverse transcriptionpolymerase chain reaction provides a sensitive index of mRNA levels in normal and osteoarthritic cartilage samples and suggests that increased expression of matrix metalloproteinase‐9 precedes fibrillation of cartilage in the development of osteoarthritis.
Systematic and random errors in compression testing of trabecular bone
Authors: Keaveny Tony M. , Pinilla Tania P. , Crawford R. Paul , Kopperdahl David L. , Lou Albert 
Published: February 2005

AbstractWe sought to quantify the systematic and random errors associated with‐artifacts in the platens compression test for trabecular bone. Our hypothesis was that while errors may depend on anatomic site, they do not depend on apparent density and therefore have substantial random components. Trabecular bone specimens were first tested nondestructively using newly developed accurate protocols and then were tested again using the platens compression test. Percentage differences in modulus between the techniques (bovine) proximal tibia [n = 18] and humerus [n = 17] and human lumbar spine, [n = 9] were in the range of 4‐86%. These differences did not depend on anatomic site (p = 0.21) and were only weakly dependent on apparent density and specimen aspect ratio (r2 < 0.10). The mean percentage difference in modulus was 32.6% representing the systematic component of the end‐artifact error. Neglecting the minor variations explained by density and specimen size (approximately 10%), an upper bound on the random error from end‐artifacts in this experiment was taken as the SD of the modulus difference (±18.2%). Based on a synthesis of data taken from this study and from the literature, we concluded that the systematic underestimation error in the platens compression test can be only approximated and is in the range of 20‐40%; the substantial random error (±12.5%) confounds correction, particularly when the sample size is small. These errors should be considered when interpreting results from the platens test, and more accurate testing techniques should be used when such errors are not acceptable.
Effects of different estrogen and progestin regimens on the mechanical properties of rat femur
Authors: Kasra M. , Vanin C. M. , MacLusky N. J. , Casper R. F. , Grynpas M. D. 
Published: February 2005

AbstractThe purpose of this study was to examine the effects of estrogen replacement, in concert with three different progestin regimens. On the mechanical properties of rat femoral cortical bone. Ninety‐two 11‐month‐old female Sprague‐Dawley rats were randomly divided into six groups and were treated for a duration of 6 months. Group‐1 rats were intact controls. group‐2 rats were ovariectomized controls, and groups 3‐6 were Ovariectomized and given continuous doses of estrogen with 5% estradiol 17B silicone‐rubber implants. Groups 4, 5, and 6 were also given different doses of progestin (norethindrone): group 4 received a continuous dose of 3 μg per animal per day, group 5 received a cyclic dose of 6 μ per animal per day for 14 days of a 28‐day cycle, and group 6 received an interrupted dose of 3 μ per animal day for 3 days of a 6‐day cycle. Femurs from each group were mechanically tested. Bending stiffness was measured by nondestructive three‐point bending tests and maximum torque capacity, by destructive torsion tests. Geometrical properties and apparent density of cortical bone were also measured. The Significant differences were: the increases in elastic modulus (measured from the three‐point bending stiffness) of group 5 (cyclic norethindrone) compared with those of group 2 (ovariectomized controls) and group 3 (estrogen only); the increases in the size represented by the moment of inertia, the moment of the area, and medial‐lateral width of group 2 compared with those of group 5; and the increases in apparent density and decreases in moment of inertia of group 6 (interrupted norethindrone) compared with those of group2. Cyclic or interrupted treatment of progestin along with continuous treatment of estrogen after ovariectomy likely improves material properties of cortical bone, increases its density, and reduces the size of the bone compared with ovariectomized rats.
Differential regulation of type‐II and type‐X collagen synthesis by parathyroid hormone‐related protein in chick growth‐plate chondrocytes
Authors: O'Keefe Regis J. , Loveys Luke S. , Hicks David G. , Reynolds Paul R. , Crabb Ian D. , Puzas J. Edward , Rosier Randy N. 
Published: February 2005

AbstractParathyroid hormone‐related protein is a critical autocrine regulator of endochondral ossification in the growth plate, as demonstrated by the severe disruption of growth‐plate structure and function in parathyroid hormone‐related protein‐deficient transgenic mice. In the present study, the effects of parathyroid hormonerelated protein on the synthesis of collagen mRNA and protein were studied in short‐term cultures of isolated chick growth‐plate chondrocytes. Parathyroid hormone‐related protein selectively inhibits type‐X collagen protein synthesis with no significant effect on type‐II collagen protein synthesis. These effects were present in all maturationally distinct populations of chondrocytes separated by countercurrent centrifugal elutriation. In cultures of resting chondrocytes, the onset of type‐X collagen expression was inhibited, while the synthesis of type‐X collagen was decreased in cultures of hypertrophic chondrocytes. Synthesis of type‐II and type‐X collagen mRNA was examined by nonradioactive in situ hybridization with synthetic oligonucleotide cDNA probes, and the level of expression was quantified using digital image analysis. Dose‐dependent suppression of type‐X collagen gene expression by parathyroid hormone‐related protein was observed, with no significant effect on type‐II collagen mRNA detected. The results were confirmed by analysis of Northern blots of total chondrocyte mRNA. These experiments demonstrated differential transcriptional regulation of type‐II and type‐X collagen, with selective suppression of type‐X collagen expression, by parathyroid hormone‐related protein in growth‐plate chondrocytes, In addition. Excellent agreement was found between traditional protein and mRNA analyses and microscopic digitial image analysis techniques, supporting the use of this convenient and sensitive assay method. Parathyroid hormone‐related protein inhibits chondrocyte maturation and is known to stimulate proliferation, suggesting that this autocrine factor may function to regulate premature hypertrophy in the growth plate.
Expression of parathyroid hormone‐related peptide in human osteoarthritis
Authors: Okano Kunihiko , Tsukazaki Tomoo , Ohtsuru Akira , Osaki Makoto , Yonekura Akihiko , Iwasaki Katsuro , Yamashita Shunichi 
Published: February 2005

AbstractTo evaluate the involvement of the expression of parathyroid hormone‐related peptide gene in human articular cartilage pathology, we performed immunohistochemical staining and in situ hybridization on specimens of femoral head cartilage obtained from 15 patients with osteoarthritis, 11 with rheumatoid arthritis, and 12 control subjects. Parathyroid hormone‐related peptide‐positive chondrocytes were observed predominantly in degenerated lesions of osteoarthritic tissue and were less evident in rheumatoid arthritic samples, while the normal cartilage expressed little parathyroid hormone‐related peptide. In addition, the level of parathyroid hormone‐related peptide expression was clearly dependent on the degree of cartilage degeneration; cartilage tissues with moderate degenerative changes contained more positive chondrocytes compared with mildly or severely degenerated cartilage. In situ hybridization confirmed the localization of parathyroid hormone‐related peptide protein and demonstrated intense expression of mRNA of the peptide in osteoarthritic samples. This is the first demonstration of parathyroid hormone‐related peptide expression in chondrocytes from pathologic articular cartilage of humans. Our results, suggest that parathyroid hormone‐related peptide may be involved in the pathophysiology of osteoarthritis.
Physical properties of rabbit articular cartilage after transection of the anterior cruciate ligament
Authors: Sah Robert L. , Yang Arlene S. , Chen Albert C. , Hant James J. , Halili Reynaldo B. , Yoshioka Makoto , Amiel David , Coutts Richard D. 
Published: February 2005

AbstractThe effect of unilateral transection of the anterior cruciate ligament on the confined compression and swelling properties of the distal femoral articular cartilage of skeletally mature rabbits at 9 weeks after surgery was determined. Gross morphological grading of the transected and contralateral control distal femora stained with India ink confirmed that cartilage degeneration had been induced by ligament transection. Osteochondral cores, 1.8 mm in diameter, were harvested from the medial femoral condyles. The modulus, permeability, and electrokinetic (streaming potential) coefficient of the articular cartilage of the osteochondral cores were assessed by confined compression creep experiments. The properties (mean ± SD) of control cartilage were: confined compression modulus, 0.75 ± 0.28 MPa; hydraulic permeability, 0.63 ± 0.28 × 10−15 m2/Pa*sec; and electrokinetic coefficient, 0.16 ± 0.31 ± 10−9 V/Pa. In transected knees, the modulus was reduced by 18% (p = 0.04), while the permeability and electrokinetic coefficient were not detectably altered. The change in modulus was accompanied by a trend (p = 0.07) toward a decrease (‐11%) in the glycosaminoglycan density within the tissue, a significant increase (p <0.001) in the water content of the cartilage after equilibration in 1 × phosphate buffered saline from 70.3 ± 4.1% in control knees to 75.2 ± 4.0% in transected knees, and little further swelling after tissue equilibration in hypotonic saline. The compressive modulus of the cartilage from both control and transected knees was positively correlated with the density of tissue glycosaminoglycan. The alterations in the physical properties of the articular cartilage after transection of the anterior cruciate ligament in the rabbit show trends similar to those observed in human and other animal models of osteoarthritis and provide further support for the use of this model in the study of cartilage degeneration.
Calcium‐mobilizing purine receptors on the surface of mammalian articular chondrocytes
Authors: Koolpe Mitchell , Benton Hilary P. 
Published: February 2005

AbstractIf we are to fully understand mechanisms of cartilage homeostasis, it is essential that we know the full catalogue of receptors present on the surface of a chondrocyte and the pathways regulated by ligands that bind to these receptors. In this study, we describe chondrocyte responses to adenosine 5′‐triphosphate and related molecules. Adenosine 5′‐triphosphate stimulated a statistically significant, dose‐dependent, transient rise in the concentration of calcium ions in Fura 2‐loaded, differentiated, primary chondrocytes. The increase occurred in the absence of extracellular calcium, indicating a mobilization from intracellular stores. The increase in concentration of cytoplasmic calcium ions induced by adenosine 5′‐triphosphate was mimicked by uridine 5′‐triphosphate but not by 2‐methylthioadenosine 5′‐triphosphate. Cytidine 5′‐triphosphate, or adenosine. Heteralogous desensitization experiments demonstrated that chondrocytes showed no subsequent response to uridirie 5′‐triphosphate after initial stimulation with adenosine 5′‐triphosphate nor did they respond to adenosine 5′triphosphate in inverse conditions, thereby indicating competition for the same receptor site. Together, these results are consistent with the presence of a P2U: receptor on the cell surface of chondrocytes. Purine‐induced calcium mobilization in passaged chondrocytes showed the same pharmacological profile with respect to aganist sensitivity, but responses were of greater magnitude than responses in primary differentiated chondrocytes, suggesting upregulation of the receptor with time in culture. Adenosine 5′‐triphosphate and uridine 5′‐triphosphate (1‐100 μM) did not alter cartilage matrix synthesis as measured by rate of incorporation of [35S]sulfate into glycosaminoglycan by cartilage explants or primary chondrocytes. Matrix degradation, measured by release of glycosaminoglycan from cartilage explants, was also unaltered by adenosine 5′‐triphosphate or uridine 5′‐triphosphate (1‐100 μM). Production of prostaglandin E2was upregulated by incubation with either adenosine 5′‐triphosphate or uridine 5′‐triphosphate. These data demonstrate the presence of a functional P2U,‐like purine receptor on the surface of primary articular chondrocytes and support the hypothesis that altered concentrations of extracellular purines may influence chondrocyte metabolism.
Glycosaminoglycans and proteoglycans from different zones of the porcine knee meniscus
Authors: Nakano Takuo , Dodd Carole M. , Scott Paul G. 
Published: February 2005

AbstractMedial and lateral knee menisci were obtained from 20‐week‐old pigs, dissected into three zones of equal width, and analyzed for collagen and glycosaminoglycan content and for types of glycosaminoglycan and proteoglycan. The thin inner zones contained about 76% collagen and 8% glycosaminoglycan (by dry weight) and the ouer zones. 93% collagen and 2% glycosaminoglycan. The most abundant glycosaminoglycan in all zones was chondroitin sulphate, accounting for about 80% of total glycosaminoglycan in the inner zones and 50–56% in the outer zones, Dermatan sulphate was the second most abundant glycosaminoglycan, present relative to chondroitin sulphate in a ratio of about 1:5–6 in the inner zones and 1:1.5 in the outer zones. Hyaluronic acid accounted for 4–5% of total glycosaminoglycan content in the inner zones and 10% in the outer zones. All compositional parameters for the middle zones were between those for the inner and outer zones. There were no statistically significant differences in composition between medial and lateral menisci. Proteoglycans were extracted and separated into two groups (large and small proteoglycans) by gel chromatography and were further characterized by gel electrophoresis. The large proteoglycans stained with use of monoclonal antibodies to chondroitin sulphate and keratan sulphate. Biglycan and decorin, two related dermatan sulphate proteoglycans, were identified in the small proteoglycan pool by their behaviour on gel electrophoresis and by immunostaining with specific antibodies. In the middle and inner zones, biglycan predominated. The observed lower dectrophoretic mobilities of dermatan sulphate proteoglycans from the inner zone compared with those from the outer zone were explained by the discovery of longer dermatan sulphate chains on the former. Collectively, these results show that the extracellular matrix of knee meniscus varies continuously across its width in a manner consistent with increased compressive loading on the thinner, inside aspect of the structure.
Limb lengthening promotes muscle growth
Authors: Day Charles S. , Moreland Morey S. , Floyd S. Steven , Huard Johnny 
Published: February 2005

AbstractStudies of limb lengthening have demonstrated successful bone formation in the distraction gap. Failure of the muscle units to lengthen leads to many complications that significantly limit the success of this approach; it is, therefore, of paramount importance to characterize the behavior of the muscle during limb lengthening. In this study, tibiae of adult rabbits were lengthened for 10 days at a rate of 1 mm/day. The proliferative ability of the lengthened muscle was characterized using bromodeoxyuridine, a thymidine analogue that is incorporated during cell division, and desmin, a muscle‐specific marker. We observed a large number of proliferating cells, specifically in the lengthened muscle, that were co‐localized with many desmin‐positive cells. The presence of bromodeoxyuridine nuclei inside desminpositive muscle fibers suggests that limb lengthening promotes muscle growth by triggering myoblast proliferation and fusion into the lengthened muscle, Our findings are consistent with those of other studies in the reviewed literature, that also suggest that limb lengthening promotes muscle growth.
Topical application of nerve growth factor improves fracture healing in rats
Authors: Grills Brian L. , Schuijers Johannes A. , Ward Alex R. 
Published: February 2005

AbstractThe aim of the present study was to examine the effects of nerve growth factor on the healing of unsplinted fractured ribs. After fracture of a rib in male rats, nerve growth factor was delivered by a miniosmotic pump to the fracture site for 7 days at the rate of 1.4 μg/day. Callus catecholamine concentrations, hone callus size, histomorphometry, and biomechanical properties of the repairing rib were measured at 7,21, and 42 days after fracture. After 21 days, concentrations of norepinephrine and epinephrine were significantly increased in the group treated with nerve growth factor compared with those in the control group (211% norepinephrine and 322% epinephrine). Also, the midline longitudinal area of non osseous (fibrous tissue and cartilage) callus of the fracture was significantly smaller (54%) and had a higher proportion of cartilage in the treated group than in the controls. By 42 days, there was only bony callus between the fracture ends in both the control group and the treated group. The treated group, however, again showed significantly elevated concentrations of norepinephrine and epinephrine (286 and 382%, respectively) and significantly elevated breaking stress (50%) and Young's modulus (51%), together wilh a reduction in the transverse cross‐sectional area of the repair site (57%). The resultant increases in effectiveness and rate of repair of bone with administration of nerve growth factor suggest that it may play an important role in the healing processes of fractured bone.
Similar effects of recombinant human insulin‐like growth factor‐I and II on cellular activities in flexor tendons of young rabbits: Experimental studies in vitro
Authors: Abrahamsson Sven‐Olof 
Published: February 2005

AbstractTo improve the understanding of factors with the potential of affecting the healing of flexor tendons, this study compared the cellular effects of recombinant human insulin‐like growth factor‐II with those of recombinant human insulin‐like growth factor‐I in matched pairs of deep flexor tendons of young rabbits. Dose‐response effects on the synthesis of DNA and matrix proteins of either factor alone or in combination were investigated in short‐term culture, and effects on synthesis and turnover of matrix components were compared in long‐term culture. Both factors stimulated proteoglycan, collagen, noncollagen protein, and DNA synthesis in a dose‐dependent manner in the range of 10–500 ng/ml. Insulin‐like growth factor‐I increased proteoglycan synthesis to as much as six times that of controls but was less potent than insulin‐like growth factor‐II. Both factors stimulated increased cell proliferation by as much as five times compared with control values, but insulin‐like growth factor‐I was more potent than insulin‐like growth factor‐II. The two factors in combination did not enhance the synthesis of matrix proteins and DNA as compared with either factor alone. Insulin‐like growth factor‐I counteracted the decrease in collagen synthesis and stimulated protein synthesis to a higher degree than insulin‐like growth factor‐II in long‐term culture. Both factors had similar effects on matrix turnover, with estimated half times (t1/2) for elimination of newly labeled proteoglycans and proteins of 11 and 8 days, respectively. Insulin‐like growth factor‐II is capable of stimulating cell proliferation and matrix metabolism in tendon explants of young rabbits at levels similar to those of insulin‐like growth factor‐I; in combination, the two growth factors are unable to augment the stimulatory effects of either of the factors alone.