bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression of collagens I, II, X, and XI and aggrecan mRNAs by bovine growth plate chondrocytes in situ
Authors: Sandell Linda J. , Sugai James V. , Trippel Stephen B. 
Published: February 2005

AbstractThe cells responsible for skeletal growth are the chondrocytes of the cartilaginous growth plate. These cells differentiate through a series of maturational stages, establishing different zones in the growth plate. Among the major functions of these cells is the production of appropriate extracellular matrix, primarily composed of collagens and proteoglycans. To determine whether matrix synthesis varies with respect to maturational stage and in which cell populations different collagens are expressed, bovine growth plates were analyzed by in situ hybridization ot mRNA and by Northern blot hybridization. The most abundant collagen mRNA in the growth plate was type‐II collagen. This mRNA was present at relatively low levels in the most immature cells of the growth plate but increased several‐fold as cells entered the proliferative stage and remained high through subsequent phases of maturation. Type‐XI collagen mRNA and mRNA for the cartilage‐characteristic proteoglycan, aggrecan, were codistributed with the type‐II collagen mRNA; however, both were present in much smaller quantities. Type‐X procollagen mRNA was localized to chondrocytes late in their maturation and was expressed at levels similar to the expression of type‐II collagen. In situ hybridization of serial sections revealed that growth plate chondrocytes in their more mature stages contain both type‐II and type‐X collagen mRNA. Type‐I collagen mRNA was not observed in growth plate chondrocytes at any maturational stage; rather, it was localized to a morphologically distinct population of cells attached to calcifying cartilage septa in the region of vascular invasion. These data indicate that the genes for major matrix constituents synthesized by the growth plate in some cases are expressed differentially at different stages of cellular maturation and in other cases are expressed coordinately. The pattern of mRNA expression suggests possible mechanisms of gene regulation.
Metabolic activity of bovine articular cartilage during refrigerated storage
Authors: Schachar N. S. , Cucheran D. J. , McGann L. E. , Novak K. A. , Frank C. B. 
Published: February 2005

AbstractThe ability of the chondrocytes in intact bovine articular cartilage (AC) to synthesize glycosaminoglycans (GAG) during short‐term refrigerated storage was examined. Closed and exposed bovine carpometacarpal joints were stored in a refrigerator for 4 hours, 1 day, 3 days, 5 days, or 7 days after the death of the animal. Full‐thickness 6 mm diameter cartilage disks were obtained from each joint, incubated in Na235SO4, digested, and assayed for GAG production. Similarly incubated cartilage samples were processed for autoradiography as a qualitative determination of 35S uptake by chondrocytes. All refrigerated samples of AC showed signs of some cellular metabolic activity. Only at 7 days did chondrocytes demonstrate a significant decline in activity. For all five storage periods, AC from joints exposed to nutrient media synthesized more GAG than cartilage from matched closed joints. These results suggest that some chondrocytes in AC destined for osteoarticular allografting retain the ability to synthesize GAG for as long as 5 days of refrigerated storage and that this synthesis is stimulated by storage of the joint surfaces in a sterile nutrient solution. While the implications of the chondrocytes' survival and metabolism for osteochondral allograft transplantation are unknown, these data indicate that intact bovine AC retains some metabolic activity for several days under the conditions described and would carry on this activity if transplanted within that period of time.
Localisation of bone‐forming cells during fracture healing by osteocalcin immunocytochemistry: An experimental study of the rabbit tibia
Authors: Stafford H. J. , Roberts M. T. , Oni O. O. A. , Hay J. , Gregg P. 
Published: February 2005

AbstractAn immunocytochemical method was used to localise osteocalcin‐producing cells during fracture healing in a rabbit model. In preliminary studies, tibial growth plates from young rabbits were used as a source of new bone formation, in order to determine the optimal tissue preparatory techniques. In the present study, a tibial shaft fracture was created in adult rabbits to study closed fracture healing. An indirect peroxidase method was used to stain paraffin‐embedded tissue sections for osteocalcin. Osteocalcin‐producing cells were positively identified at the periosteal and endosteal surfaces near the fracture site. Osteocalcin staining was not demonstrated in the surrounding soft tissues. At the interface between newly formed bone trabeculae and the cartilage layer within the callus, chondrocytic cells consistently showed localisation of osteocalcin. Within cartilaginous areas of the callus, some chondrocytes showed positive staining for osteocalcin. These cells were often seen in theproximity of blood vessels. The findings suggest that during fracture healing, under certain conditions, chondrocytes are capable of producing osteocalcin and thus could be considered capable of possible transformation into osteoblasts.
In vitro elution of ciprofloxacin from polymethylmethacrylate cement beads
Authors: Dimaio Frank R. , O'Halloran James J. , Quale John M. 
Published: February 2005

AbstractThe use of antibiotic‐impregnated polymethylmethacrylate (PMMA) cement beads for the local delivery of antibiotics in the treatment of chronic osteomyelitis has become a standard orthopaedic practice. The increasing resistance to antibiotics of organisms associated with orthopaedic infections has led to interest in the incorporation of more effective antibiotics into PMMA cement. Ciprofloxacin, a synthetic fluoroquinolone, is potent against a broad spectrum of bacteria associated with osteomyelitis. In this study, strands of ciprofloxacin‐impregnated PMMA cement beads were prepared with 0.2, 0.5, or 1.0 g of ciprofloxacin per 40 g of PMMA. The elution concentration of ciprofloxacin was at least 1–2 mcg/ml for 7 days (0.2 g), 30 days (0.5 g), and 42 days (1.0 g). This concentration is equivalent to the minimum inhibitory concentration for the common pathogens associated with osteomyelitis. Concurrent systemic and local ciprofloxacin therapy appears to be a method for the treatment of chronic osteomyelitis.
Neuropeptides in the human intervertebral disc
Authors: Ashton I. K. , Roberts S. , Jaffray D. C. , Polak J. M. , Eisenstein S. M. 
Published: February 2005

AbstractThe innervation of the human intervertebral disc was investigated by immunochemical methods. Immunoreactivity to the general nerve marker protein gene product (PGP 9.5) was found in the outer annulus fibrosus of 11 of 12 discs removed during anterior arthrodesis for back pain. PGP 9.5‐immunoreactive fibres ran between and across the collagenous lamellae, both in association with blood vessels and distant from them, and extended at least 3 mm into the disc. No innervation was observed in the nucleus pulposus. Fine fibres (< 1 μm in diameter) immunoreactive to calcitonin gene‐related peptide and substance P (neuropeptides located in sensory and possibly nociceptive nerves) were identified in eight and four of the annuli fibrosi, respectively. Nerve fibres immunoreactive to vasoactive intestinal peptide and to the c‐flanking peptide of neuropeptide Y were found in the majority of specimens of annulus fibrosus that were examined.
Adaptation of skeletal muscle in limb lengthening: A light diffraction study on the sarcomere length In situ
Authors: Matano Tetsuro , Tamai Kazuya , Kurokawa Takahide 
Published: February 2005

AbstractAdaptation of skeletal muscle during limb lengthening was assessed by measurement of the length of sarcomeres in situ. An external fixator was applied to the rabbit radius and ulna to elongate the forelimb by 3.5 mm, while allowing all the joints to be free. At regular intervals after the operation, the extensor digitorum lateralis muscle of the fifth digit was exposed in situ and the length of the sarcomeres was measured by a laser diffraction technique. The sarcomeres, which had stretched to 3.51 μm immediately after elongation of the bone, became shorter with the passage of time. On postoperative day 9, the length was 3.10 μm, which was similar to the length of the unstretched muscle. These results indicated structural adaptation of the muscle to a new length and could explain why the efficiency of muscle function is maintained after limb lengthening. When these findings are combined with our previous results, it appears that stretch‐induced changes in sarcomere length are common in immobilized and nonimmobilized muscles.
Reflex hamstring contraction latency in anterior cruciate ligament deficiency
Authors: Beard David J. , Kyberd Peter J. , O'Connor John J. , Fergusson Colin M. , Dodd Christopher A. F. 
Published: February 2005

AbstractDecreased dynamic stability of the knee joint associated with functional disability is a feature of anterior cruciate ligament deficiency (ACLD). The purposes of this study were to examine the between‐limbs difference in reflex contraction latency of the hamstring muscles in patients with unilateral ACLD and to investigate its relationship with instability and function. Fifty patients with arthroscopically diagnosed unilateral ACLD were measured bilaterally for reflex hamstring contraction latency (RHCL), and 20 normal volunteers were similarly tested. The subjects were measured in a position of single‐limb full weight‐bearing with the knee flexed 30°. An anteriorly directed shear force was applied to the tibia, and surface electromyographs (EMGs) recorded the activity of the hamstrings in response to the applied force. The latency of contraction was defined as the time from initial tibial movement, identified by accelerometry, to the onset of increased hamstring EMG activity. Both legs were tested and a between‐limbs difference was computed. A significant difference in RHCL wasfound between the limb with ACLD and the control limb. The mean RHCL of the limb with ACLD was nearly double that of the unaffected limb, for a significant mean between‐limbs difference (p < 0.05). The mean between‐limbs difference for the control subjects was not statistically significant. The conclusion is that patients with ACLD have an increased RHCL of the injured leg. As the RHCL is dependent on proprioceptive activity around the joint, it can be used as a measure of proprioceptive ability. The loss of the neurophysiological protective reflex involving the anterior cruciate ligament and hamstrings in patients with ACLD is likely to be a contributory factor in the decreased joint stability experienced by these patients.
Comparison of primate and canine models for bone ingrowth experimentation, with reference to the effect of ovarian function on bone ingrowth potential
Authors: Shaw James A. , Wilson Scott C. , Bruno Anthony , Paul Emmanuel M. 
Published: February 2005

AbstractBone growth into porous composite (mesh‐bead) titanium plugs was compared in elderly (postmenopausal) female monkeys and female dogs as a means of validating the cross‐species interpretations so often made between data from research on dogs and human applications. The effect of oophorectomy on bone ingrowth in the canine model was defined by the comparison of data on fractional ingrowth in animals that had had oophorectomy and in control animals that had had a sham operation. No significant difference in bone growth into the experimental plugs was identified between the two animal models, which lends credence to cross‐species interpretation of existing data from dogs. The presence or absence of active ovaries did not affect the ingrowth fraction in the canine model; this suggests that existing data are not confounded by the lack of control of ovarian function. Estrogen depletion does not appear to influence bone ingrowth adversely.
Comparison of absorption of aqueous lidocaine and liposome lidocaine following topical application on rabbit vessels
Authors: Hou Sheng‐Mou , Yu Hsiu‐Ying 
Published: February 2005

AbstractLiposomes are small particles that encapsulate lidocaine to form topical drug carriers. Forty rabbits were used to compare the absorption of aqueous lidocaine with that of liposome lidocaine after application of each on femoral and iliac vessels. Both agents entered the circulation rapidly. The serum levels of lidocaine were significantly lower and the peaks in concentration appeared later after the use of liposome lidocaine than after the use of aqueous lidocaine. This phenomenon was due to local accumulation of liposome lidocaine and slow release of lidocaine from the liposome. As a topical spasmolytic agent, liposome lidocaine may be superior to the aqueous form due to a lower serum concentration and less total absorption.
Effect of cyclic and static tensile loading on water content and solute diffusion in canine flexor tendons: An in Vitro study
Authors: Hannafin Jo A. , Arnoczky Steven P. 
Published: February 2005

AbstractThis study was designed to determine the effects of various loading conditions (no load and static and cyclic tensile load) on the water content and pattern of nutrient diffusion of canine flexor tendons in vitro. Region D (designated by Okuda et al.) of the flexor digitorum profundus was subjected to a cyclic or static tensile load of 100 g for times ranging from 5 minutes to 24 hours. The results demonstrated a statistically significant loss of water in tendons subjected to both types of load as compared with the controls (no load). This loss appeared to progress with time. However, neither static nor cyclic loading appeared to alter the diffusion of 3H‐glucose into the tendon over a 24‐hour period compared with the controls. These results suggest that any benefit in tendon repair derived from intermittent passive motion is probably not a result of an increase in the diffusion of small nutrients in response to intermittent tensile load.
Identification of integrin receptors on cultured human bone cells
Authors: Saito Taichi , Albelda Steven M. , Brighton Carl T. 
Published: February 2005

AbstractThe interactions of bone cells with their surrounding extracellular microenvironment may be mediated by integrins, a family of heterodimeric glycoproteins consisting of α and β subunits that noncovalently interact to form cell‐substratum adhesion receptors. We previously described the integrins on calvarial bone cells in rats with use of polyclonal antibodies against some integrin subunits. In the present study, we expanded this initial characterization by employing a more complete panel of monoclonal antibodies to identify integrins on human bone cells. Minced fragments of trabecular bone obtained during total knee arthroplasty were grown in culture until bone cells became confluent. The cells then were dissociated, plated again, grown to confluence, and assayed for alkaline phosphatase activity, response of cyclic adenosine monophosphate to stimulation with parathyroid hormone, and osteocalcin content. The percentage of the cells that adhered to various substrates was measured; 60–70% adhered to type‐I collagen, fibronectin, vitronectin, and poly‐D‐lysine; 40–50% adhered to type‐IV collagen, laminin, and gelatin; and only 10% adhered to fibrinogen. Flow cytometric analysis with anti‐integrin monoclonal antibodies and sodium dodecyl sulfate‐polyacryamide gel electrophoresis analysis of immunoprecipitates of the human bone cells revealed high levels of α1β1, α3β1, α5β1, and αVβ5 integrins and much lower levels of α2β1, α4β1, αVβ1, and αVβ3 integrins. This description of the integrin repertoire of cultured human bone cells represents the first step toward an understanding of the role played by integrins in the growth, maintenance, and repair of bone.
Foot inversion‐eversion and knee kinematics during walking
Authors: Lafortune M. A. , Cavanagh P. R. , Sommer H. J. , Kalenak A. 
Published: February 2005

AbstractThe purpose of this study was to monitor selected aspects of the three‐dimensional kinematics of the knee during walking with regular shoes and with modified shoes that induced either pronation or supination of the foot. Steinmann traction pins were inserted into the right tibia and femur of five adult men who had apparently normal lower extremities. Target clusters mounted onto the pins were filmed by four cine cameras operating at 100 frames/sec. Two trials per subject were analyzed for each of the three experimental conditions: regular running shoes, running shoes with a 10° valgus wedge, and running shoes with a 10° varus wedge. The different types of footwear induced only minor kinematic changes at the knee during the stance phase of walking. The angular patterns of the tibiofemoral joint were modified by less than 1°, whereas the translatory patterns were altered by 2 mm. Immediately following foot‐strike, the valgus‐wedge shoes caused the tibia to rotate internally 4° more than the varus‐wedge shoes, but at the tibiofemoral joint no consistent differences in the pattern of internal‐external rotation between normal and modified footwear were measurable. These findings suggest that, in the healthy lower extremity, increased internal and external tibial rotation is resolved at the hip joint, with changes at the tibiofemoral joint that barely are detectable with the techniques used in this study.
Technique for in vivo measurement of the three‐dimensional kinematics and laxity characteristics of the ankle joint complex
Authors: Siegler Sorin , Wang Dinghua , Plasha Elizabeth , Berman Arnold T. 
Published: February 2005

AbstractWe introduce here a technique to measure the three‐dimensional kinematics and laxity characteristics of the ankle joint complex in vivo. The system consists of an optoelectric, kinematic data acquisition system that is used to measure the motion of the ankle joint complex in response to controlled moments applied through a system of pneumatic actuators. As a first step toward development of the method into a quantitative diagnostic tool for injuries of ankle ligaments, we addressed the following questions: (a) What is the reliability for measurement of range of motion and laxity of the ankle joint complex? (b) Are there significant differences in laxity between the left and right joints of a healthy individual? and (c) Are there significant differences in laxity of the ankle joint complex between men and women? To answer these questions, we performed repeated measures of range of motion and laxity of paired ankles in a population of 18 healthy young individuals. The high intraclass correlation coefficients obtained from the statistical analysis indicate that the new experimental system is highly reliable in measurement of total range of motion and total laxity of the ankle joint complex. We further concluded that, within the statistical power available in our experimental design, there are no significant differences in either range of motion or laxity between left and right ankles of healthy individuals or between men and women.
Scanning electron microscopic observations of the vascular structure of vertebral end‐plates in rabbits
Authors: Oki Sadaaki , Matsuda Yoshiro , Itoh Toshio , Shibata Taihoh , Okumura Hideo , Desaki Junzo 
Published: February 2005

AbstractWe used scanning electron microscopy to examine the microcirculation in the vertebral end‐plates of rabbits. The arteriola arborizes and swells at the end‐plate and then coils to make a microvessel loop. This loop is the structure we refer to as a vascular bud. We suggest that these loop structures of the capillaries play a major role in the nutrition of the intervertebral discs.
Centrifugal and biochemical comparison of proteoglycan aggregates from articular cartilage in experimental joint disuse and joint instability
Authors: Müller Francisco J. , Setton Lori A. , Manicourt Daniel H. , Mow Van C. , Howell David S. , Pita Julio C. 
Published: February 2005

AbstractTwo models involving altered joint loading were compared with regard to their effects on the biochemical composition and proteoglycan aggregate structure of articular cartilage. Disuse atrophy was created in greyhound dogs by nonrigid immobilization of the right knee in 90° of flexion, and joint instability was created by transection of the anterior cruciate ligament. Similarities and differences between the two experimental groups at two different time periods were examined to investigate why joint instability induces progressive and irreversible changes to the articular cartilage, whereas joint disuse induces changes that may be reversible when the joint is remobilized. The following studies were performed on the cartilage from all experimental and control groups: (a) compositional analyses to determine water, uronate, and hydroxyproline contents; (b) high performance liquid chromatography for detection of hyaluronan and chondroitin sulfates; and (c) centrifugation analyses of nondissociatively extracted and purified proteoglycans to isolate and quantify the populations of monomers and slow and fast‐sedimenting families of aggregates. In general, all cartilage was found to have a decreased ratio of proteoglycan to collagen after 4 weeks of disuse, and this ratio returned to control values at 8 weeks. In contrast, cartilage had an elevated ratio of proteoglycan to collagen as well as increased hydration at 12 weeks after transection of the anterior cruciate ligament. The most striking contrast between the two models was the finding of an approximately 80% decrease in the content of hyaluronan at both time periods after transection of the anterior cruciate ligament, with no evidence of a change after disuse. The results of centrifugation analyses indicated a significant decrease in the quantity of proteoglycan aggregates in both models. However, this decrease was associated primarily with a loss of slow‐sedimenting aggregates after disuse and a loss of both slow and fast‐sedimenting aggregates after transection of the anterior cruciate ligament. Furthermore, the population of fast‐sedimenting aggregates. The preservation of fast‐sedimenting aggregates as well as hyaluronan after periods of joint disuse but not joint instability suggests a possible mechanism for the reversibility of cartilage changes. Although the proteoglycan aggregates were depleted after disuse atrophy, it is possible that an aggregate‐depleted matrix could recover when normal proteoglycan synthesis is resumed. In contrast, although synthesis may be maintained or elevated after transection of the anterior cruciate ligament, the matrix may not be repopulated with aggregates because there is an insufficient amount of hyaluronan.