bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fiber composition and fiber transformations in neck muscles of patients with dysfunction of the cervical spine
Authors: Uhlig Yvonne , Weber Barbara R. , Grob Dieter , Müntener Markus 
Published: February 2005

AbstractBiopsies of ventral neck muscles (sternocleidomastoid, omohyoid, and longus colli) and dorsal neck muscles (rectus capitis posterior major, obliquus capitis inferior, splenius capitis, and trapezius) were taken from 64 patients who underwent spondylodesis for cervical dysfunction of different etiologies. The muscle fibers were classified histochemically as type I, IIA, IIB, or IIC (transitional or intermediate fibers) according to the pH lability of their myofibrillar ATPase. Signs of muscle fiber transformations were observed in all muscles investigated, as evidenced by an increased relative amount of type‐IIC fibers. The transformations occurred independently of (a) the type of muscle (i.e., more “postural” or more “phasic”), (b) the sex and age of the patient, (c) the type of condition, and (d) the presence of additional neurological deficits. Thus, the same pattern of muscular reaction was found in patients with rheumatoid arthritis as in patients with soft‐tissue injuries of the neck (e.g., “whiplash injury”). In the ventral muscles and the obliquus capitis inferior, the occurrence of transformations correlated strongly with the duration of symptoms; in the ventral muscles the vast majority of transformations were encountered in patients with a shorter history of symptoms, whereas in the obliquus capitis inferior the reverse occurred. In the other dorsal muscles, no correlation with the duration of symptoms was found. Muscles in which transformations had ceased displayed, on average, a significantly higher percentage of fast type‐IIB fibers than were found in muscles with ongoing transformations. This strongly indicates that the transformations proceeded in the direction from “slow oxidative” to “fast glycolytic”.
Clinical reproducibility of dual energy X‐ray absorptiometry
Authors: Williams‐Russo Pamela , Healey John H. , Szatrowski Ted P. , Schneider Robert , Paget Stephen , Ales Kathy , Schwartzberg Patricia 
Published: February 2005

AbstractDual energy x‐ray absorptiometry is a technique advocated for the measurement of bone mass throughout the skeleton, and recently it has been used to measure changes in periprosthetic bone mass after joint replacement. The accuracy and precision of the method in clinical patient populations have not been firmly established. This study sought to establish the short‐term reproductibility of measurements made with dual energy x‐ray absorptiometry of multiple sites in a large sample of elderly patients with rheumatic disease. Reproductibility was assessed in the lumbar spine and in three femoral sites in 69 patients participating in a longitudinal clinical trial. In each patient, absorptiometry was performed twice in the same day at as many as five time points over a 2‐year period. The mean (±SD) baseline bone density was 0.783 ± 0.128 g/cm2 for the femoral neck and 1.015 ± 0.218 g/cm2 for the lumbar spine. The correlations between the duplicate baseline measurements of the spine were excellent (r = 0.9936, p < 0.001) and were stable over the 2‐year period; the mean difference between the duplicate baseline measurements was 1.82 ± 1.54% and the mean coefficient of variation was 1.29%. Measurements in the femur were much less precise: these values were 3.61 ± 3.14% and 2.55% in the femoral neck, 3.66 ± 4.35% and 2.59% in the greater trochanter, and 5.28 ± 5.61% and 3.73% in Ward's triangle. This study evaluated the short‐term reproductibility of dual energy x‐ray absorptiometry in a clinical population. The reproductibility of a technique must be taken into account when it is applied longitudinally to follow patients over time. The reproductibility of bone densitometry of the spine in large clinical populations with orthopaedic and rheumatic disease was similar to that reported for in vitro measurements and for very small sample studies of healthy normal subjects. However, the reproductibility of densitometry of femoral sites was much poorer than that for spinal sites. Reproducibility is a significant methodological issue for the use of dual energy x‐ray absorptiometry to assess the effect of osteoporosis therapies on the hip as well as the change in periprosthetic bone mass around a hip prosthesis. The poorer reproductibility of the measurements in the femoral sites suggests that a much wider margin of error is required in the interpretation of within‐patient change in bone mass over time.
Contaminated fractures of the tibia: A comparison of treatment modalities in an animal model
Authors: Curtis Mark J. , Brown Phillip R. , Dick James D. , Jinnah Riyaz H. 
Published: February 2005

AbstractExternal fixation is the current standard treatment for skeletal stabilization of open tibial fractures, but intramedullary fixation techniques have become increasingly popular. The aim of this study was to compare, in an animal model, the susceptibility to infection of contaminated fractures stabilized with external fixation with that of contaminated fractures fixed with intramedullary locking nails with or without reaming. A unilateral osteotomy of the tibia was performed in 15 goats under general anesthesia. Each osteotomy was stabilized with either (a) a unilateral biplanar external fixator, (b) an 8 mm diameter intramedullary rod inserted without reaming of the medullary cavity, or (c) a 10 mm diameter rod inserted after reaming. A standardized inoculum of Staphylococcus aureus, 103 colony forming units per milliliter, was placed at each osteotomy site on a piece of absorbable gelatin sponge, to simulate contamination of an open fracture. Antibiotics were not administered. The animals were allowed full activity after the procedure. Fourteen days postoperatively, the animals were killed, radiographs of the tibiae were taken, and the tibiae were harvested in a sterile manner. Multiple specimens for quantitative microbiological analysis were taken from the fracture site and from sites 3 cm distal and 6 cm proximal to the fracture. Additional specimens of bone were taken for histological study. Clinical, radiographic, and microbiological analysis demonstrated that, in this animal model, there were significantly fewer and less severe infections in fractures fixed with external fixation than in those fixed with an intramedullary nail with or without reaming. There was marked cortical necrosis in tibiae that had been fixed with nailing and reaming.
Closeness of fit of uncemented stems improves the strain distribution in the femur
Authors: Hua J. , Walker P. S. 
Published: February 2005

AbstractDifferences in the cross‐sectional shapes of intramedullary stems are expected to affect the strains in the femur, a close proximal fit being proposed as particularly advantageous. We compared uncemented femoral stems of different designs, as well as a cemented stem, using the intact femur as a control. The collarless stems were custom‐made, standard asymmetric, symmetric (i.e., neutral), and cemented symmetric. These different types of stem were inserted in sequence into eight cadaver femurs. A photoelastic coating technique was used to give a measure of the shear strains over the bone surface. The mean reductions of maximum shear strains in the upper 30 mm of the proximal‐medial regions for the custom, asymmetric, symmetric, and cemented stems were 11, 24, 6, and 75%, respectively. The strains for the symmetric stem were concentrated in the proximal‐medial region just below the neck resection line and then decreased rapidly below that level. For the asymmetric stems, the relative strains in the proximal‐anterior and proximal‐medial regions were dependent on the tightness of fit in the anterior‐posterior and medial‐lateral directions. The custom stems consistently produced a pattern of strain distribution that, overall, was closer to normal than that of the other stems; extremes at the anterior and medial regions were avoided. The strains down the entire medial side of the cemented stem were significantly less than for the intact femur or for the uncemented stems.
Evaluation of vascular compliance and vasoconstrictive reactions in amputated hindlimbs of rats
Authors: Ono Hiroshi , Nakagawa Yoji , Mizumoto Shigeru , Tomita Naohide , Tamai Susumu 
Published: February 2005

AbstractThe vascular compliance and the contractility of vascular smooth muscle of preserved, amputated hindlimbs of rats were evaluated using a fresh blood extracorporeal circulatory system. Vascular compliance was measured under physiologic circulatory conditions (blood pressure of the amputated limb was maintained at 80–150 mm Hg [10–20 kPa]) and found not to differ significantly from that of freshly amputated limbs after storage at 4°C for 12 hours. However, after more than 24 hours of storage at 4°C, the vascular compliance decreased significantly (p < 0.01). To evaluate the contractility of vascular smooth muscle, the arterial blood pressure in the amputated limbs was transiently increased with injections of norepinephrine. The contractility could be preserved for at least 12 hours at 4°C; however, it decreased markedly after more than 24 hours. The vascular compliance and vasoconstrictive reactions of the amputated limbs were maintained for at least 12 hours at 4°C.
Osteoarthritis in cynomolgus macaques II. Detection of modulated proteoglycan epitopes in cartilage and synovial fluid
Authors: Carlson Cathy S. , Loeser Richard F. , Johnstone Brian , Tulli Hermina M. , Dobson Denene B. , Caterson Bruce 
Published: February 2005

AbstractThe purpose of the present study was to determine the usefulness of the monoclonal antibodies 7‐D‐4 and 3‐B‐3 as biomarkers of severity of naturally occurring osteoarthritis in the knee joints of adult cynomolgus macaques. The antibodies were used to immunolocate chondroitin sulfate proteoglycan epitopes in articular cartilage or synovial fluid from knee joints with a range in severity of osteoarthritis. The joints were examined radiographically, grossly, microradiographically, and histologically to characterize the severity of disease, and the results of three different methods of proteoglycan analysis (immunohistochemistry, enzyme‐linked immunosorbent assay, and Western blot analysis) were compared. Subjectively, the degree of positive immunostaining for 7‐D‐4 was minimal in normal sites and increased as damage to articular cartilage increased. The scores for 7‐D‐4 immunostaining in the medial tibial plateau (the site most severely involved in this model) were correlated significantly with severity of damage to articular cartilage (p < 0.05, r2 = 0.50), thus supporting the subjective observations. The ratio of 7‐D‐4 to sulfated glycosaminoglycans in synovial fluid also was correlated with the score for 7‐D‐4 immunostaining in the medial tibial plateau (p < 0.05, r2 = 0.54) and with the score for 3‐B‐3 immunostaining in the medial femoral condyle (p < 0.05, r2 = 0.65). There were no significant correlations among scores for 3‐B‐3 immunostaining, severity scores, and the ratios of 3‐B‐3 to sulfated glycosaminoglycans in the synovial fluid. By Western blot analysis, both epitopes were sensitive markers of early cartilage damage in young adult monkeys but were less sensitive in older monkeys. This work provides evidence that measurement of the epitope recognized by 7‐D‐4 in synovial fluid or, by immunohistochemical or Western blot methods, in articular cartilage has potential use as a marker of severity of naturally occurring osteoarthritis.
Influence of short‐term hydrostatic pressure on organization of stress fibers in cultured chondrocytes
Authors: Parkkinen Jyrki J. , Lammi Mikko J. , Inkinen Ritva , Jortikka Matti , Tammi Markku , Virtanen Ismo , Helminen Heikki J. 
Published: February 2005

AbstractThe present study describes changes in the organization of stress fibers that occur in articular cartilage chondrocytes subjected to hydrostatic pressure. Primary cultures of chondrocytes from bovine articular cartilage, grown on coverslips, were subjected to 5, 15, or 30 MPa hydrostatic pressure at 37°C. The pressure was applied continuously or cyclically at two frequencies: 0.125 Hz (4 seconds of pressure and 4 seconds of no pressure) or 0.05 Hz (1 second of pressure and 19 seconds of no pressure) for a period of 2 hours. Control chondrocytes showed a polygonal form with prominent stress fibers extending across the cells. The exposure of cells to 30 MPa pressure caused a nearly total disappearance of stress fibers and retraction of the cells from each other. With pressure at 15 MPa or cyclic pressure, the number of cells with stress fibers was decreased. In cells subjected to 5 MPa pressure, the stress fibers resembled those in control chondrocytes. The pressure effects were reversible after 2 hours. Pressure had no effect on the staining pattern of vinculin, which suggests that microfilaments are more vulnerable to pressure than vinculin. The results indicate that cytoskeletal changes may be an integral part of the response of chondrocytes to hydrostatic pressure.
Proposal for the regulatory mechanism of Wolff's law
Authors: Mullender M. G. , Huiskes R. 
Published: February 2005

AbstractIt is currently believed that the trabecular structure in bone is the result of a dynamic remodeling process controlled by mechanical loads. We propose a regulatory mechanism based on the hypothesis that osteocytes located within the bone sense mechanical signals and that these cells mediate osteoclasts and osteoblasts in their vicinity to adapt bone mass. A computer‐simulation model based on these assumptions was used to investigate if the adaptation of bone, in the sense of Wolff's law, and remodeling phenomena, as observed in reality, can be explained by such a local control process. The model produced structures resembling actual trabecular architectures. The architecture transformed after the external loads were changed, aligning the trabeculae with the actual principal stress orientation, in accordance with Wolff's trajectorial hypothesis. As in reality, the relative apparent density of the structure depended on the magnitude of the applied stresses. Osteocyte density influenced the remodeling rate, which also is consistent with experimental findings. Furthermore, the results indicated that the domain of influence of the osteocytes affects the refinement of the structure as represented by separation and thickness of the struts. We concluded that the trabecular adaptation to mechanical load, as described by Wolff, can be explained by a relatively simple regulatory model. The model is useful for investigating the effects of physiological parameters on the development, maintenance, and adaptation of bone.
Integrative repair of articular cartilage in vitro: Adhesive strength of the interface region
Authors: Reindel Eric S. , Ayroso Annamarie M. , Chen Albert C. , Chun Denise M. , Schinagl Robert M. , Sah Robert L. 
Published: February 2005

AbstractThe objective of this study was to quantify the strength of the repair tissue that forms at the interface between pairs of cartilage explants maintained in apposition in an in vitro culture system. Articular cartilage explants were harvested from calves and from adult bovine animals, dissected into uniform blocks, and incubated in pairs within a chamber that maintained a 4 × 5 mm area of tissue overlap. Following 1–3 weeks of incubation, integrative repair was assessed by testing samples in a tensile single‐lap configuration to estimate adhesive strength. After incubation in medium containing 20% fetal bovine serum, the adhesive strength between pairs of calf cartilage blocks and pairs of adult bovine cartilage blocks increased at a rate of 7.0 and 10.5 kPa/week, respectively. This repair process appeared to be dependent on viable cells, since lyophilization of adult bovine cartilage before incubation completely inhibited the development of an interface with a measurable adhesive strength. The repair process was dependent on serum components in the medium. Incubation of sample pairs for 3 weeks in medium supplemented with 20% fetal bovine serum resulted in a relatively high proteoglycan content as well as a relatively high adhesive strength (34 kPa), whereas incubation in basal medium with or without 0.1% bovine serum albumin resulted in a 54–70% lower proteoglycan content and a 65–88% lower adhesive strength. Samples incubated for 3 weeks with serum also had a 20% higher DNA content than samples maintained in basal medium. Histological analysis indicated some cell division at the free surfaces of the explant and also occasional cells within the interface region between explants.
Effects of basic fibroblast growth factor, transforming growth factor‐β1, insulin‐like growth factor‐1, and insulin on human osteoarthritic articular cartilage explants
Authors: Posever James , Phillips Frank M. , Pottenger Lawrence A. 
Published: February 2005

AbstractThis study evaluated the effects of basic fibroblast growth factor, transforming growth factor‐β1, insulin‐like growth factor‐1, and insulin on the incorporation of thymidine and sulfate in human osteoarthritic articular cartilage. Tissue explants were obtained from 11 patients undergoing total knee arthroplasty and were categorized as nonfibrillated or fibrillated cartilage. The explants were cultured for 22 days, with changes of medium and growth factor every 72 hours, and labeled with [3H]thymidine and [35S]sulfate. Growth factors were used in the following concentrations: basic fibroblast growth factor at 1, 10, and 100 ng/ml; transforming growth factor‐β1 at 0.5, 5, and 50 ng/ml; insulin‐like growth factor‐1 at 0.15, 1.5, and 15 ng/ml; and insulin at 0.05, 0.5, and 5 μg/ml. Basic fibroblast growth factor decreased thymidine incorporation to 70% and sulfate incorporation to less than 20% that of the growth factor‐free controls. Transforming growth factor‐β1 had no significant effect on thymidine incorporation, whereas the concentrations studied inhibited sulfate incorporation to approximately 40% that of the controls. At the concentrations tested, insulin‐like growth factor‐1 had no significant effect on incorporation of either thymidine or sulfate. In contrast, insulin significantly stimulated the incorporation of both. Compared with growth factor‐free controls, insulin maximally increased thymidine incorporation by a factor (± EM) of 2.36 ± 0.47 and 1.69 ± 0.19 in nonfibrillated and fibrillated explants, respectively; sulfate incorporation was maximally increased 1.60 ± 0.24 and 1.92 ± 0.29‐fold for nonfibrillated and fibrillated explants, respectively. Of the factors tested, insulin demonstrated the greatest promise for promoting a synthetic response that may contribute to the regeneration of osteoarthritic cartilage.
Torsional loads in the early postoperative period following total hip replacement
Authors: Kotzar G. M. , Davy D. T. , Berilla J. , Goldberg V. M. 
Published: February 2005

AbstractTorques generated in one subject during the early postoperative period were measured with a telemeterized total hip component. The patient was examined during gait, stair ascent, rising from a chair, and single‐limb stance. The torques were plotted against both the resultant joint contact force and the force component directed along the stem axis. During gait, the maximum torque was 35 Nm, recorded at a walking velocity of 1.7 m/sec. The peak torques during stair ascent and during rising from a seated position were found to be 23 and 15 Nm, respectively. The maximum value for torque measured in this study was 37 Nm during one attempt at single‐limb stance. Comparison of plots for torque versus stem‐axis component for the four activities shows that the torque increased more rapidly for chair exits than for gait up to resultant contact force values of as much as 1,000 N. For stair ascent, the same was true to values of 1,400 N. Within any given activity, the relationship between stem torque and resultant or stem‐axis force showed considerable variability. These results indicate that experiments evaluating the stability of femoral components in total hip arthroplasty should incorporate a component directed along the stem axis, as well as a component normal to the plane of the prosthesis. The results also suggest that theoretical stress analysis models should consider the broad variability in the orientation of the joint force at the hip.
Restoration of function of the thumb flexor apparatus requires repair of the oblique and one adjacent flexor tendon pulley
Authors: Esplin V. S. , Tencer A. F. , Hanel D. P. , Cosio M. Q. 
Published: February 2005

AbstractDamage to the pulleys of the thumb flexor apparatus may cause bow‐stringing of the tendon and affect muscle function. An experiment using the hands and distal forearms of cadavers was designed to determine which damaged pulleys increase excursion length of the flexor tendon with constant tendon and resisting loads. Each specimen was mounted to a loading frame with a dead weight pinned to the tip of the thumb. The thumb flexor tendon was clamped to an actuator that applied a fixed load and measured excursion of the tendon. Ranges of motion of the thumb joint were also measured. The thumb flexor apparatus of each specimen was tested intact first, with the hand in flexed, neutral, and extended positions; then it was tested with progressive sectioning of pulleys from proximal to distal in one group and from distal to proximal in a second group. The length of excursion increased significantly with all pulleys cut but there was no effect on on overall range of motion of the thumb. With proximal to distal sectioning, no change in tendon excursion occurred when the flexor retinaculum and the first annular pulleys were cut, until the oblique pulley was sectioned, leadving only the second annular pulley intact (range, 1.17–1.31 times that of intact excursion, dependent on position of the hand). With distal to proximal sectioning, tendon excursion was not affected when the second annular and oblique pulleys were cut but did increase when the first annular pulley was sectioned, leaving only the flexor retinaculum intact (range, 1.28–1.36 times that of intact excursion). Dependent on the location of damage, therefore, an intact oblique or first annular pulley can maintain normal excursion of the tendon.
Development of a musculoskeletal extremity health status instrument: The musculoskeletal function assessment instrument
Authors: Martin Diane P. , Engelberg Ruth , Agel Julie , Snapp Deborah , Swiontkowski Marc F. 
Published: February 2005

AbstractDespite an increasing reliance on the use of health status measures to assess and evaluate medical care, no single instrument is currently available for use with the broad range of patients with musculoskeletal disorders of the extremities that is commonly seen in clinical practice. In this paper, we report on the development of the Musculoskeletal Function Assessment instrument, a 100‐item self reported health status instrument that is designed to meet this need. The instrument was developed in two phases During the first phase, items were selected on the basis of interviews with 135 patients and 12 clinicians and from reviews of existing health status instruments. The items then were grouped into categories. During the second phase, the instrument was tested for reliability and content validity using a sample of 327 patients with one of five musculoskeletal disorders of the upper and lower extremities (fractures, soft‐tissue injuries, repetitive motion disorders, osteoarthritis, and rheumatoid arthritis). The patients were selected from both community and academic sites. The Musculoskeletal Function Assessment instrument met standards for test‐retest reliability and internal consistency. Content validity also was demonstrated, based on a review of item selection procedures, expert opinion, and the distribution of scores on the instrument.