bluuebunny/crossref_metadata_2025_split huggingface dataset:
Macrophage colony‐stimulating factor and interleukin‐6 release by periprosthetic cells stimulates osteoclast formation and bone resorption
Authors: Neale Susan D. , Sabokbar Afsaneh , Howie Donald W. , Murray David W. , Athanasou Nicholas A. 
Published: February 2005

AbstractPeriprosthetic bone loss is an important contributory factor for aseptic loosening of total joint replacements. It has recently been shown that osteoclast precursor cells are present in the wear particle‐associated macrophage infiltrate found in the membrane surrounding loose implants and that these cells are capable of differentiating into osteoclastic bone‐resorbing cells. Long‐term co‐culture of arthroplasty‐derived macrophages and the rat osteoblast‐like cell line, UMR‐106, in the presence of 1,25 (OH)2D3 results in the formation of numerous multinucleated cells that are positive for tartrate‐resistant acid phosphatase and vitronectin receptor and capable of extensive lacunar bone resorption. The aim of this study was to determine the effect of cytokines/growth factors, known to be present in the arthroplasty membrane, on this process of osteoclast differentiation. During osteoclast formation, increased levels of macrophage colony‐stimulating factor, interleukin‐6, and to a lesser extent, interleukin‐1β, but not tumour necrosis factor α, were detected in the co‐culture supernatants. Addition of neutralising antibodies to human interleukin‐1β or tumour necrosis factor α to the co‐culture system did not inhibit osteoclast formation. In contrast, co‐cultures to which neutralising antibodies to human macrophage colony‐stimulating factor or interleukin‐6 were added contained fewer cells positive for tartrate‐resistant acid phosphatase and vitronectin receptor and formed significantly fewer resorption pits. Time‐course studies showed that macrophage colony‐stimulating factor and interleukin‐6 increase osteoclast formation mainly in the early stages of osteoclast differentiation. These results indicate that the release of macrophage colony‐stimulating factor and interleukin‐6 by activated cells in the arthroplasty membrane is likely to contribute to pathological bone resorption associated with aseptic loosening by stimulating differentiation of mononuclear phagocyte osteoclast precursors into mature bone‐resorbing cells.
Polyethylene wear vector in vivo: A three‐dimensional analysis using retrieved acetabular components and radiographs
Authors: Yamaguchi Motoi , Hashimoto Yasushi , Akisue Toshihiro , Bauer Thomas W. 
Published: February 2005

AbstractPolyethylene wear of the acetabular component can be described as one or more vectors. To help clarify the mechanisms of wear advancement in vivo, we used a combination of retrieved implants and radiographs to describe the three‐dimensional wear vectors in total hip arthroplasty. The wear vectors in 41 retrieved implants from a single manufacturer were measured with use of the shadowgraph technique, and the spatial orientation of each implant was calculated from serial anteroposterior pelvic radiographs. On the basis of the combination of the wear vector in the implant and implant orientation in the pelvis, the wear vectors in vivo were determined. The mean wear vector was directed 8.1° lateral in the coronal plane and 4.1° posterior in the sagittal plane. The wear vector in vivo showed a relatively wide range of directions, not necessarily coinciding with the commonly presumed resultant force in the hip. The wear vectors were not associated with the spatial orientation of the acetabular components, but cups with impingement demonstrated more anterior wear than did those without impingement. Our results suggest that the process of polyethylene wear is not as simple as previously described and that several factors influence advancement of wear in vivo.
Differential expression of integrin subunits in canine knee ligament fibroblasts
Authors: Bhargava Madhu M. , Beavis Andrew J. , Edberg Jeffery C. , Warren Russell F. , Attia Erik T. , Hannafin Jo A. 
Published: February 2005

AbstractA method for measuring the expression of integrin subunits on the cell surface of knee ligament fibroblasts was developed with use of flow cytometry and immunofluorescence. The ligament cells exhibited uniform size and density, as shown by forward and side‐scatter properties, and showed minimal nonspecific binding of isotype control antibodies compared with unstained cells. All cells expressed the α5 integrin subunit; lateral collateral ligament cells stained with antibody to α5 showed a mean fluorescence intensity 2‐fold higher than that of medial collateral ligament cells, 1.5‐fold higher than that of posterior cruciate ligament cells, and 3‐fold higher than that of anterior cruciate ligament cells, indicating a greater expression of the α5 subunit by lateral collateral ligament cells than by medial collateral, posterior cruciate, and anterior cruciate ligament cells. All cells expressed the β1 integrin subunit; the expression by posterior cruciate ligament cells was 3‐fold higher than that by medial collateral ligament or lateral collateral ligament cells and 5‐fold higher than that by anterior cruciate ligament cells. All cells expressed the β3 integrin subunit; the expression by posterior cruciate ligament cells was 1.5, 3, and 4.5‐fold greater than that by lateral collateral, anterior cruciate, and medial collateral ligament cells, respectively. Our data suggest there is a differential expression of integrin subunits in knee ligament fibroblasts, and this in part may explain differences in their attachment and adherence to extracellular matrix molecules.
Adhesion strength differential of human ligament fibroblasts to collagen types I and III
Authors: Yang Li , Tsai Cliff M‐H. , Hsieh Adam H. , Lin Victor S. , Akeson Wayne H. , Paul Sung K‐L. 
Published: February 2005

AbstractFibroblasts embedded in the amorphous healing tissue matrix of ligaments migrate into damaged sites during the inflammatory process that precedes the formation of new connective tissue after ligament injury. Cell motility involved in this migration is strongly influenced by cellular adhesion to proteins of the extracellular matrix. The adhesion mechanism of interest in this study is the attachment of fibroblasts from the anterior cruciate and medial collateral ligaments to types I and III collagen, two fibrillar collagens secreted by fibroblasts during tissue repair. Types I and III collagen constitute a major portion of these ligaments and are assembled by fibroblasts into long cable‐like fibrils in the extracellular space. In this study, a micropipette aspiration technique was used to measure the force required to separate fibroblasts of the anterior cruciate and medial collateral ligaments from substrates composed of type I or III collagen, each at a concentration of 2 or 5 μg/ml. Approximately 1,200 fibroblasts from the anterior cruciate ligament and 1,600 from the medial collateral ligament were used, and the adhesion force and area of these cells were determined. Fibroblasts from the anterior cruciate ligament exhibited greater adhesion force than did those from the medial collateral ligament for all concentrations of types I and III collagen. In addition, the adhesiveness of fibroblasts from both ligaments was dependent on seeding time for all experimental conditions. To determine the adhesiveness per unit area, defined here as the adhesion strength, the adhesion force was normalized by the adhesion area. At early seeding times (15‐45 minutes), fibroblasts from the anterior cruciate ligament exhibited greater adhesion strength on surfaces coated with type‐I collagen than did those from the medial collateral ligament. However, for both collagen substrates, adhesion strength for fibroblasts from the anterior cruciate ligament decreased with seeding time whereas that for fibroblasts from the medial collateral ligament remained relatively constant for all seeding periods (15‐75 minutes).
Stiffness, viscosity, and upper‐limb inertia about the glenohumeral abduction axis
Authors: Zhang Li‐Qun , Portland Gregory H. , Wang Guangzhi , Diraimondo Carl A. , Nuber Gordon W. , Bowen Mark K. , Hendrix Ronald W. 
Published: February 2005

AbstractTo evaluate the dynamic properties of the shoulder and understand how they are controlled by the central nervous system, glenohumeral‐joint stiffness and viscosity and upper‐limb inertia were quantified under various levels of muscle contraction in seven healthy human subjects. Through a cast attachment, the upper limb was perturbed in a precise pattern by a computer‐controlled servomotor to manifest the dynamic properties of the joint. The recorded joint position and torque were used to estimate joint stiffness and viscosity and upper‐limb inertia. With moderate muscle contraction, the stiffness and viscosity increased several fold. A stiffer shoulder joint associated with stronger muscle contraction made the shoulder more stable and protected it from potential injuries during strenuous tasks. Joint viscosity, especially the stronger viscous damping associated with more strenuous contraction, smoothed shoulder movement and stabilized the joint. From the control viewpoint, the glenohumeral joint responded to the central nervous system more quickly with increasing muscle contraction, which was useful during strenuous tasks. On the other hand, the central nervous system controlled stiffness and viscosity synchronously so that it dealt with only a nearly constant damping ratio of the joint over various levels of contraction, which simplified its task substantially. This approach quantified the dynamic and static properties of the shoulder under various levels of contraction more accurately and completely than a manual test, and it can potentially be used to evaluate changes in these properties caused by musculoskeletal injuries and their surgical treatments.
An in vivo model for load‐modulated remodeling in the rabbit flexor tendon
Authors: Malaviya P. , Bultler D. L. , Boivin G. P. , Smith F. N. L. , Barry F. P. , Murphy J. M. , Vogel K. G. 
Published: February 2005

AbstractThis study tested the hypothesis that eliminating in vivo compression to the wrap‐around, fibrocartilage‐rich zone of the flexor digitorum profundus tendon results in rapid depletion of fibrocartilage and changes in its mechanical properties, microstructure, extracellular matrix composition, and cellularity. The right flexor digitorum profundus tendons of 2.5‐3‐year‐old rabbits were translocated anteriorly to eliminate in vivo compression and shear to the fibrocartilage zone and, at 4 weeks after surgery, were compared with tendons that had sham surgery and with untreated tendons. The translocated tissue showed a significant increase in equilibrium strain under a compressive creep load (p < 0.05). The thickness and area of the fibrocartilage zone also decreased significantly (p < 0.05). The nuclear density decreased by 40% in the fibrocartilage zone (p < 0.005); however, nuclear shape and orientation were not significantly altered. Glycosaminoglycan content in the fibrocartilage zone was also depleted by 40% (p < 0.02). The tightly woven basket weave‐like mesh of collagen fibers in the zone appeared more loosely organized, suggesting matrix reorganization due to translocation. Moreover, immunoreactive type‐II collagen and link protein in the fibrocartilage zone also decreased. With use of this unique in vivo model, this research clearly elucidates how changing tissue function (by removing compressive forces) rapidly alters tissue form.
Biomechanical evaluation of early fracture healing in normal and diabetic rats
Authors: Funk James R. , Hale Joseph E. , Carmines David , Gooch H. Lee , Hurwitz Shepard R. 
Published: February 2005

AbstractDiabetes mellitus has been shown to alter the properties of bone and impair fracture healing in both humans and animals. The objective of this study was to document changes in the structural and material properties of intact bone and bone with healed fractures in diabetic rats compared with nondiabetic controls after 3 and 4 weeks of healing. Rods were inserted in the right femurs of control rats and rats with streptozotocin‐induced diabetes, and the femurs were fractured in a standardized procedure and then allowed to heal for 3 and 4 weeks. After death, all femurs were mechanically tested to failure in torsion. The degree of healing was quantified for each animal by normalizing mechanical parameters for the femur with a healed fracture with those for the intact contralateral femur. At both time points of healing, diabetic rats exhibited inferior healing compared with that of control animals in terms of failure torque, failure stress, structural stiffness, and material stiffness of the femur with the healed fracture relative to the intact contralateral femur (p < 0.05). Our results demonstrate that the recovery of structural and material strength in femurs with healed fractures in diabetic rats is delayed by at least 1 week compared with that in controls.
Role of alpha‐1 adrenoceptor subtypes mediating constriction of the rabbit ear thermoregulatory microvasculature
Authors: Li Zhongyu , Silver William P. , Koman L. Andrew , Strandhoy Jack W. , Rosencrance Eileen , Gordon Stan , Smith Thomas L. 
Published: February 2005

AbstractAn acute in vivo preparation of the microvasculature of the rabbit ear was used to evaluate the functional role of alpha1 (α1)‐adrenoceptor subtypes in thermoregulatory microcirculation. The effect of α1‐adrenoceptor subtype blockade on phenylephrine‐induced vasoconstriction was assessed with the α1A, α1B, and α1D‐adrenoceptor‐selective antagonists 5‐methyl‐urapidil (10−8 M), chloroethylclonidine (10−5 M), and 8‐[2‐[4(2‐methoxyphenyl)‐1‐piperazinyl]ethyl]‐8‐azaspirol[4.5]decane‐7,9‐dionedihydrochloride (BMY7378) (10−6 M), respectively. The results demonstrated that pretreatment of the ear microvasculature with 5‐methylurapidil or BMY7378 shifted the phenylephrine concentration‐response curve rightward and significantly changed the log of the phenylephrine concentration, causing half‐maximum stimulation (EC50) in arterioles (p < 0.05). BMY7378 shifted the phenylephrine concentration‐response curve of the arteriovenous anastomoses about 100‐fold rightward (p < 0.05). All three α1‐adrenoceptor antagonists eliminated the vasoconstrictive effects of phenylephrine on venules. The results indicate that the ear microvasculature has a heterogenous distribution of α1‐adrenoceptor subtypes. The α1A and α1D‐adrenoceptor subtypes appear to have a greater influence on constrictive function in arterioles, whereas the α1D‐adrenoceptor is the dominant constrictor of arteriovenous anastomoses. In general, the α1‐adrenoceptor does not play a major vasoconstrictor role in venules. Chloroethylclonidine, an irreversible α1B‐adrenoceptor antagonist, induced contractile responses in the ear microvasculature, probably due to its α2‐adrenoceptor agonist effects. This study extended our understanding of the adrenergic receptor control mechanisms of a cutaneous thermoregulatory end organ characterized by two parallel perfusion circuits providing nutritional and thrmoregulatory functions.
In vivo technique to quantify the internal‐external rotation kinematics of the human glenohumeral joint
Authors: Novotny John E. , Woolley C. Todd , Nichols Claude E. , Beynnon Bruce D. 
Published: February 2005

AbstractInternal and external rotation of the humerus are often related to instability, injury mechanisms, and surgical and rehabilitation outcomes at the glenohumeral joint. The goal of this study was to develop a technique to quantify the internal‐external rotation kinematics of the glenohumeral joint in human subjects, including the rotational range of motion, neutral‐zone laxity, and flexibility. For both arms of 10 normal subjects, the rotational range of motion of the humerus was assessed at 45° of abduction with 4 Nm of appplied moment to produce internal and external rotations about the long axis. The neutral zone was defined as the portion of the rotational range of motion that occurred between +1 and −1 Nm of applied internal‐external rotation torque. The flexibility was determined from the slope of the moment‐rotation curve from 1 to 4 Nm of applied moment. The repeatability of the device during two trials on the same day and two trials 1 week apart was determined. There were no significant differences between the two same‐day and two across‐day trials for each outcome measure. The internal‐external rotational range of motion was 139.4° (SD 40.5°). The neutral‐zone laxity was 77.8° (SD 46.0°). With a linear approximation, the external rotation flexibility (20.1° Nm [SD 13.7°/Nm]) was four times greater than the internal rotation flexibility (5.8°/Nm [SD 5.1°/Nm]). The changes in the magnitude of the laxity, the ratio between the laxity and the range of motion, or the values for flexibility determined with this technique could be used to describe joint laxity, surgical outcome, and rehabilitation progress.
Adhesion formation can be reduced by the suppression of transforming growth factor‐β1 activity
Authors: Fukui Naoshi , Tashiro Toshiyuki , Hiraoka Hisatada , Oda Hiromi , Nakamura Kozo 
Published: February 2005

AbstractSurgery or trauma often results in restrictive adhesions around joints or tendons that cause severe functional impairment. The formation of adhesion is essentially a fibrogenetic process; therefore, peptide growth factors, such as transforming growth factor‐β, are assumed to play central roles in its development. The purpose of this study was to test the hypothesis that suppression of transforming growth factor‐β1 activity reduces adhesion formation. Sixty rabbits were prepared and randomly divided into six groups of 10. Intraarticular adhesions were created in the right knee joints by cortical bone shaving and subsequent cast immobilization for 4 weeks. In animals in three of the six groups, transforming growth factor‐β1 activity was suppressed by continuous administration of the neutralizing antibody in three graded doses; animals in the other three groups were used as controls. Four weeks after the surgery, the casts were removed and the adhesions were assessed macroscopically, histologically, biomechanically, and biochemically. Gross observation showed that the neutralizing antibody had suppressed adhesion formation in a dose‐dependent manner. This is consistent with biomechanical measurement results demonstrating that the antibody reduced the flexion contractures. Histologically, the adhesion in our model was fibrous tissue and the adhesions in the animals in the antibody groups were thin and loose in comparison with the controls. Biochemical analyses further supported these results, demonstrating that administration of the antibody reduced collagen content in the adhesions with a predominance of type‐I collagen. Thus, this study showed that suppression of the actions of transforming growth factor‐β1 reduced adhesion formation. Considering the various possible measures to control the activity of the growth factor, suppression of transforming growth factor‐β may be a novel, potent approach to preventing adhesions.
Increased concentrations of nitrate and nitrite in the cyst fluid suggesting increased nitric oxide synthesis in solitary bone cysts
Authors: Komiya Setsuro , Kawabata Rikimaru , Zenmyo Michihisa , Hashimoto Sanshiro , Inoue Akio 
Published: February 2005

AbstractThe etiology and treatment of a solitary bone cyst have remained undefined. Surgical treatments have not been encouraging, because a less invasive corticosteroid‐injection treatment has afforded good results. However, there has been little scientific rationale supporting corticosteroid treatment. In recent reports, bone‐resorbing factors, including matrix metalloproteinases, prostaglandins, interleukin‐1, and oxygen free radicals, have been demonstrated in the cyst fluid. To better elucidate the pathophysiology of the solitary bone cyst, we examined the activities of nitric oxide and cytokines in the cyst fluid as well as in the cyst membrane. The levels of nitrate and nitrite were significantly higher in the cyst fluid than in serum. Immunostaining of cells in the stroma and lining cells of the cyst wall was strongly positive for inducible nitric synthase. The levels of interleukin‐6 and interleukin‐1β in the cyst fluid were elevated, and cells in the cyst membrane were positive for tumor necrosis factor‐α, interleukin‐6, and interleukin‐1β. Cultured cells from the cyst membrane were induced in the production of nitrate and nitrite in response to cytokine treatment. These findings suggest that the solitary bone cyst was in a state favorable for the production of nitric oxide.
Mechanical performance of standard and cannulated 4.0‐mm cancellous bone screws
Authors: Brown Greg A. , McCarthy Tracey , Bourgeault Craig A. , Callahan Dennis J. 
Published: February 2005

AbstractThe mechanical performance of bone screws is determined by their pull‐out strength (holding power), compressive force, stripping torque, yield bending moment, ultimate bending moment, and fatigue strength. These parameters are related to the parameters of the screw design, including major thread diameter, minor thread diameter, thread length, pitch, shaft diameter, cannulation diameter, and material properties. The goal of the study was to theoretically predict the static performance of five 4.0‐mm, 45–46‐mm‐long, cancellous, partially threaded standard and cannulated bone screws and compare the predictions with experimental measurements. A secondary goal was to determine if cannulation of the bone screw diminished its mechanical performance. The predicted values for pull‐out force, compressive force, and stripping torque were determined by the thread length, major thread diameter, and thread shape factor. The screws with the largest major thread diameter and longest thread length had the greatest pull‐out force, compressive strength, and stripping torque. However, when correcting for the thread length, a higher thread shape factor compensated for a smaller major diameter. The coefficient of determination (r2) for the correlation between the predicted and measured pull‐out force improved from 0.75 to 0.90 when the theoretical model included the thread shape factor. The yield and ultimate bending moments are a function of the section modulus and material properties of the screw. The Ace solid screw had the greatest section modulus and yield and ultimate bending moments. The experimental data support the theoretical models for predicting the mechanical performance of bone screws. The disign of the bone screws can be optimized on the basis of theoretical modeling. The strong correlation between the predicted and measured parameters allows comparison between bone screws without repeated experimental tests. Theoretical and experimental results show that cannulation of the bone screw did not inherently diminish its mechanical performance.