bluuebunny/crossref_metadata_2025_split huggingface dataset:
Failure of the rabbit tibial growth plate to respond to the long‐term application of a capacitively‐coupled electrical field
Authors: Armstrong Peter F. , Brighton Carl T. 
Published: February 2005

AbstractA continuous 5‐V peak‐to‐peak, 60 kHz capacitively‐coupled sine wave signal was applied to the proximal tibial growth plate in fifteen 9‐week‐old male New Zealand white rabbits for 6 weeks. A pair of flexible stainless steel “injectrodes” was held in place medially and laterally on the surface of the proximal hindlimb in each rabbit by means of tape wrappings. The electrodes were connected to a 9‐V battery‐operated power unit carried in a dorsal pouch in a body vest worn by each rabbit. Control animals wore the identical apparatus, only the power unit was inactive. Small Tantalum markers were inserted into the anteromedial aspect of the proximal tibial metaphysis 1 cm distal to the proximal tibial growth plate in all of the animals, control and experimental, 2 weeks prior to the onset of electrical stimulation. The distance between the proximal lateral tibial spine and the Tantalum marker, between the Tantalum marker and the apex of the distal tibial intercondylar notch, and between the proximal tibial spine and the distal notch was measured from roentgenograms made at the time of bone marker insertion, at the time of electrode application to the limb, and at the end of the stimulation period. Results indicate that there was no significant difference in tibial lengths between the stimulated and control groups. There was significantly less total body weight gain in both the experimental and control animals than that which occurred in paired normal animals during the same period of time. This failure to thrive may be responsible for the resultant lack of longitudinal growth stimulation of the capacitive coupling. The observed failure to thrive was thought to be due to encumbrance imposed on the rabbits by the legwraps and the body vest.
Role of internal fixation in infection of open fractures: Studies with Staphylococcus aureus and Proteus mirabilis
Authors: Merritt Katharine , Dowd James D. 
Published: February 2005

AbstractStudies of infections in open fractures are described. The hamster was chosen as the experimental model. Osteotomies of the femur were created with an osteotomy saw. Some osteotomies were left to heal and others were fixed with an 0.9mm K‐wire. The infection rates in fixed and unfixed fractures were compared. The first group of hamsters with fixed and unfixed osteotomies was returned to cages with open wounds. There was no difference in the infection rate at 2 weeks. The second group was deliberately contaminated with Staphylococcus aureus and then returned to cages with open wounds. In this group, the infection rate at 2 weeks was lower in the internally‐fixed fractures than in the unfixed fractures. The third group was deliberately contaminated with the gram negative organism Proteus mirabilis. In these animals, the infection rate was increased in the presence of the internal fixation device. The fourth group was deliberately contaminated with both Staphylococcus aureus and Proteus mirabilis. The infection rate in these animals was very high; Proteus was recovered from those animals with internal fixation and Staphylococcus was recovered from those animals without internal fixation. These studies in the hamster document the usefulness of this animal as an inexpensive and reproducible model for studying infection of open fractures. The hamsters tolerated the procedure well, and wound and fracture healing progressed satisfactorily.
Systemic administration of glycosaminoglycan polysulphate (Arteparon) provides partial protection of articular cartilage from damage produced by meniscectomy in the canine
Authors: Hannan Neil , Ghosh Peter , Bellenger Christopher , Taylor Thomas 
Published: February 2005

AbstractBilateral medial meniscectomy was undertaken in 14 mature beagles. Another two underwent arthrotomy (sham‐operated controls). One week after surgery, six of the meniscectomised animals were administered glycosaminoglycan polysulphate (Arteparon) (2 mg/kg) subcutaneously three times a week for 3 weeks, then twice weekly until killed 23 weeks later. Two months before death all animals were given Na235SO4(1.0 mCi/kg) intravenously. At autopsy, articular cartilage (AC) from the medial and lateral compartments, as well as from the femoral trochlear groove and femoral head, was sampled. Proteoglycans (PGs) were isolated by 4.0MGuanidine hydrochloride (GuHCI) extraction of AC and purified by ultracentrifugation. The PG monomers were assayed for hexuronic acid, protein, and hexosamines (galactosamine/glucosamine), and their ability to aggregate. The results indicated that Arteparon provided some protective effect to AC in the menisectomised compartment as demonstrated histologically by reduced surface fibrillation, diminished chondrocyte cloning, and maintence of alcianophilia. The levels of PGs and hexuronate‐protein ratios in medial AC of drug‐treated meniscectomised animals were found to be comparable to sham controls, whereas these parameters in the nondrug‐treated meniscectomized group were depressed.
Force analysis of the patellar mechanism
Authors: Ahmed A. M. , Burke D. L. , Hyder A. 
Published: February 2005

AbstractThe aim of this study is an experimental evaluation of a force analysis of the patellar mechanism based on the assumption that patellofemoral contact is frictionless. At first, the geometric characteristics of contact surfaces, a prior knowledge of which is necessary for quantitative analysis, were measured from radiographs of 42 fresh‐frozen knee specimens in the flexion range 0–120°. The results were then used in the analysis to predict the relations between the forces acting on the patella. For the evaluation of the analysis, the ratio of the tension in the ligamentum patellae and the rectus femoris was measured in ten specimens during simulation of two knee functions: (1)“leg raising” against a resistance; and (2)“static lifiting”. The effect of flexion angle on the ratio is found to be rather complex. With increasing flexion, the ratio increases initially up to 30°, then decreases up to 90°, and finally increases again beyond 90°. The ratio is above unity up to around 45° and below that in the remaining flexion range. The analysis has been found to predict not only the characteristic variation of the ratio but also its magnitude with reasonable accuracy. It has been concluded that for an accurate prediction of the patellofemoral joint reaction, the force analysis needs to be based on the geometry of the contact surfaces. This implies that the mechanical consequences of surgical procedures involving tibial tubercle relocation cannot be inferred simply on the basis of their effect on the patellar mechanism angle, but that they also require consideration of their effect on the contact geometry.
Femoral anteversion: Assessment based on function axes
Authors: Yoshioka Yuki , Cooke T. Derek V. 
Published: February 2005

AbstractThis study describes a clinically oriented anatomical assessment of anteversion on 32 cadavers ranging from 61 to 89 years. The method used a three‐dimensional reference system based on functional axes of the femur. Each soft tissue‐free femur was mounted on an osteometric table and aligned to its functional axes. The long axes were defined as passing from the centre of the femoral head to the femoral attachment of the posterior cruciate ligament (PCL). A line that ran through the PCL attachment (equal distal origin of this system) and was parallel to a transepicondylar line served as a transverse axis. Anteversion of the femur was defined as an angle formed to the transverse axis by a line running through the centre of the femoral head through the midpoint of the narrowest segment of the femoral neck. The measurement mean for anteversion among these specimens was 7.4° with a range from −10.8° (retroversion) to 22.1°. There was no statistical difference in mean values (p<0.05) between sexes or between right and left sides of the group; however there were large variations for anteversions when each side in the same individual was compared (although there was no dominant side). Retroversions were observed in four of 32 femurs (12.5%). No correlation was found between the anteversion in these femurs and rotational geometry at the knee. We compared our data with those obtained by conventional techniques, by which anteversion for each femur was measured after the bone had been placed on a flat surface. The anteversion so defined was 13.1°, i.e., an average of 5.7° more external rotation induced by condylar disproportion. Such data indicate the influence of condylar disproportion on the measurement of anteversion and reveal the potential errors in measurements of anteversion that may be imposed by variations in condylar dimensions. The measurement method may be applied to computer tomographic radiographs of femora in vivo.
The use of laser doppler flowmetry to evaluate anterior cruciate blood flow
Authors: Schlehr Frank J. , Limbird Thomas A. , Swiontkowki Marc F. , Keller Tony S. 
Published: February 2005

AbstractThe purpose of this study was to quantitate the blood flow of the anterior cruciate ligament in vivo. Functional flow was evaluated using laser Doppler flowmetry (LDF), for which the output signal, blood cell flux (BCF), is expressed in terms of volts. Ten patients undergoing routine arthroscopic surgery with clinically intact anterior cruciate ligaments were selected at random for participation in the study. Under arthroscopic visualization, a 2.2‐mm probe was placed through a trocar sleeve into the anterior cruciate ligament after the arthroscopic procedure. Pulsatile flow within the ligament was observed in all patients. The mean maximum BCF value ranged from 101 to 274 mV; SD range was + 3–9 mV. The mean minimum BCF ranged from 75 to 197 mV; SD range was + 0 to 9 mV. Laser Doppler flowmetry offers significant promise as a method for measurement of in vivo anterior cruciate and cruciate substitution blood flow.
Degeneration and the chemical composition of the human lumbar intervertebral disc
Authors: Pearce Richard H. , Grimmer Beverley J. , Adams Mark E. 
Published: February 2005

AbstractFifteen lumbar spines were collected postmortem. The intervertebral discs were assigned morphological grades and were analyzed for water, collagen, and proteoglycan. In order of increasing degeneration, five grade 0, four grade 1, 45 grade 2, 12 grade 3A, and nine grade 3B discs were identified. The proteoglycan concentration fell progressively with increasing grade, although the concentrations of each component overlapped extensively among the grades. Grade 2 discs showed no consistent differences from adjacent grade 3A or 3B discs and all discs in three spines with no grade 3A or 3B discs had proteoglycan concentrations below 52 mg/g fresh weight. Four of five spines with at least one disc of proteoglycan concentration above this value contained no grade 3A or 3B discs. These observations support the hypothesis that low proteoglycan concentrations in all the discs of a spine precede degeneration.
Effect of electric currents on DNA synthesis in rat osteosarcoma cells: Dependence on conditions that influence cell growth
Authors: Noda Masaki , Johnson David E. , Chiabrera Allesandro , Rodan Gideon A. 
Published: February 2005

AbstractEffects of sinusoidal 60‐Hz electric currents on DNA synthesis in rat osteosarcoma cell (ROS 17/2.8) in culture were investigated using agar electrodes. This exposure system eliminates electrochemical effects at electrode surfaces, minimizes the contribution of magnetic fields and produces no detectable temperature changes (< t 0. l°C) at current densities of up to 1,500 pA r.m.s. (root mean square)/cm2. Thirty‐four hours exposure to electric current at intensities of 300–400 pA r.m.s./cm2 enhanced DNA synthesis by 20% relative to controls. The effect depended on serum concentration, cell seeding density, and the age of the cell population at the time of seeding: effects were seen at 0.2% fetal bovine serum, in cells seeded 4 days after previous passage, at 20,000 cells/cm2. These findings indicate that sinusoidal electric currents can mildly enhance DNA synthesis in these cells under growth‐limiting conditions.
Platelet pathology in minimal curve idiopathic scoliosis: An attempt to predict curve progression
Authors: Meyer S. , More R. , Yarom R. 
Published: February 2005

AbstractPlatelets from adolescents with minimal curve scoliosis (mcs) (7–18?) and healthy control subjects were examined for morphometry under the electron microscope and tested for calcium content and surface negative charge. These parameters have previously been found to be abnormal in severe idiopathic scoliosis (is) patients. Significantly more patients than control subjects showed deviations from normal in all tests. Two tests in particular, the average number of dense bodies per cell and an increased surface negative charge, were the most frequent abnormalities. In an attempt to assess the possibility of using platelet tests for prediction of curve progression, statistical comparisons were made and discriminant scores were generated for each patient. The results were compared with the clinical findings after a 2‐to 3.5‐year follow‐up. The predictions proved to be incorrect although each of the five patients who had curve progression had some platelet abnormality. It is concluded that although platelet pathology does occur in early idiopathic scoliosis, it cannot be used as a prognostic indicator of curve progression.
The effect of proximally and fully porous‐coated canine hip stem design on bone modeling
Authors: Bobyn J. D. , Pilliar R. M. , Binnington A. G. , Szivek J. A. 
Published: February 2005

AbstractPorous coated canine femoral hip replacement implants were evaluated for biological fixation by bone ingrowth and the effect of the extent of porous coating on bone modeling. The Co‐Cr alloy implants were either fully porous coated or coated only on the proximal 40% of the stem. Two implants of each type were studied 9, 16, and 36 months after surgery. Implant fixation and bone modeling were assessed radiographically throughout the implant periods and histologically after the test animals were killed. All 12 implants appeared stably fixed within the femur and were bone‐ingrown in the porous region. Radiographic features such as proximal medial and anterior cortical thinning, proximal cancellous bone hypertrophy, and new endosteal bone formation near the stem tip were noted within the first postoperative year, with no appreciable change thereafter. The extent of proximal cortical thinning varied from virtually none to as much as 40%, being more prominent with the proximally coated implants at 16 months and with the fully coated implants at 36 months. Of consistent note was cancellous hypertrophy at the junction of porous and smooth implant surfaces with proximally coated implants and new endosteal bone formation and ingrowth at the stem tip of fully coated implants. These results indicate that the proximally porous‐coated implant design causes increased proximal stress transfer, but this does not necessarily preclude proximal cortical resorption.
Increased transsynovial transport with continuous passive motion
Authors: Danzig Larry A. , Hargens Alan R. , Gershuni David H. , Skyhar Michael J. , Sfakianos Peter N. , Akeson Wayne H. 
Published: February 2005

AbstractThirteen freshly killed immature rabbits were used to study the effect of continuous passive motion (CPM) on regional nutritional pathways of the medial and lateral menisci and the transport of a solute from synovial fluid to the patellar tendon. A bolus of 35SO4 was injected into each knee joint cavity. The right knee underwent CPM for 1 h, whereas the left knee was immobilized (rest extremity). Both knees were then rapidly resected and immediately frozen. The medial and lateral menisci were removed and sectioned into anterior, middle, and posterior thirds for Group 1 animals; in Group 2 animals a portion of patellar tendon was harvested. Radioactivity as counts per minute per milligram of tissue was counted in a scintillation counter. The posterior portion of the lateral meniscus in the rest extremity had significantly higher uptake than the extremity that underwent CPM (p < 0.001). In the extremity at rest, the posterior third of the lateral meniscus had a significantly higher uptake than that of the middle third (p = 0.04). In Group 2 rabbits, the patellar tendon of the knee undergoing CPM had significantly higher uptake as compared with the patellar tendon of the knee at rest (p = 0.02). These results indicate that diffusion from synovial fluid to meniscal cells is an important mechanism of transport for low‐molecular‐weight nutrients such as sulfate; CPM does not facilitate this mechanism. However, even with a decreased amount of 35SO4 left in the CPM‐treated joint, the amount taken up by these menisci was still roughly the same as that in the rested knee that had a higher concentration of 35SO4 available in the synovial cavity. Regional differences are small for the 1‐h period examined in this study. Transarticular transport of sulfate from the joint space to an extraarticular tissue (patellar tendo) is facilitated by convective flow induced by CPM.
Torsion and bending analysis of internal fixation techniques for femoral neck fractures: The role of implant design and bone density
Authors: Swiontkowski Marc F. , Harrington Richard M. , Keller Tony S. , Van Patten Peter K. 
Published: February 2005

AbstractTo evaluate pin/screw/plate fixation for management of femoral neck fractures, 39 proximal femora were tested in both torsion and flexion under physiological loading conditions. Three, four, or five implants of six commonly used multiple‐fixation devices, and a sliding hip screw with and without an additional 6.5‐mm cancellous screw were examined in paired femora. The intact and postfixation femora were initially subjected to a single applied moment, and the torsion and bending stiffness were determined from the load‐deformation data. Postfixation femora were also subjected to cyclic loading in flexion at three load ranges, and fixation was judged successful if no failure occurred on or before 1,500 cycles of 667 to 2,000 N of a combined compressive force and moment. Anterior‐posterior and lateral radiographs of each specimen were taken after fixation in order to evaluate Singh's index of bone density, fracture reduction, implant placement, and cross‐sectional diameter of the femoral neck. Bone density was also evaluated by computed tomography (CT) and physical measurement of core samples obtained from the femoral head. The results indicate that there appears to be no justification for the use of more than three pin/screw implants for management of femoral neck fractures. Bone density was found to correlate with fracture stability and may be a useful predictor of fixation success.
Osteonal remodeling in response to screw implantation in in canine femora
Authors: Martin R. B. 
Published: February 2005

AbstractWe examined the patterns of osteonal remodeling associated with the implantation of a screw in the femoral diaphysis of four mongrel dogs. The dogs were killed at intervals ranging from 11 to 93 days after implantation, and resorption spaces and tetracycline‐labeled osteons were counted as functions of postimplant time and distance from the screw. The contralateral femur was used as a control. We found that implantation of the screw initiated a sequence of remodeling activity at the screw site; numerous resorption spaces were observed after 3 weeks, followed by numerous refilling osteons at 7 weeks. When sequential sections along the shaft adjacent to the screw were examined, it appeared that the increased resorption and refilling activity subsequently migrated away from the screw site, both proximally and distally. Also, both the implanted and control femurs exhibited occasional zones along the shaft within which the numbers of labeled osteons were sharply reduced. These “extinction zones” were found to be asscoiated with local maxima in resorption space density. We further noted that the ratio of singly to doubly labeled osteons in the experimental control femurs was high as compared with that in humans, but similar to that previously observed in the canine iliac crest.
Obesity and decreased femoral anteversion in adolescence
Authors: Galbraith Robert T. , Gelberman Richar H. , Hajek Paul C. , Baker Lori A. , Sartoris David J. , Rab George T. , Cohen Mark S. , Griffin Paul P. 
Published: February 2005

AbstractThe degree of femoral anteversion in a group of obese adolescent children and a group of adolescent children of normal weight was determined by either magnetic resonance imaging or computerized axial tomography. Compared with the children of normal weight, the obese children showed a significantly reduced angle of femoral anteversion. Increased biomechanical forces generated across the hip joint of obese children leads to increased remodeling of the femoral neck. This may account for the association of slipped capital femoral epiphysis, reduced femoral anteversion, and obesity in the adolescent population.
Extent of artificial limb use following rehabilitation
Authors: Holden Jean M. , Fernie Geoffrey R. 
Published: February 2005

AbstractThe extent of prosthesis use is reported for 104 lower limb amputees from the onset of gait training up to 2 years later. Subjects were divided into groups according to age (265 years or < 65 years) and amputation level. An analysis of variance including the factors of age and level of amputation was done. Unilateral trans‐tibial (UTT) amputees progressed more quickly during the inpatient gait training program that did unilateral trans‐femoral (UTF) subjects (p < 0.05). UTT subjects also walked more than UTF subjects just prior to discharge (p < 0.05), during the first year after discharge (p < 0.01), and during the second year after discharge (p < 0.01). Similarly, younger patients progressed more quickly in gait training (p < 0.05) and walked more than older subjects throughout the study period (p < 0.05). There were no significant interactions between age and amputation. The extent of walking of these amputees is compared with the minimal levels required for them to function in different living environments. At the time of discharge from the inpatient gait training program, older unilateral amputees and trans‐femoral amputees were not able to walk the 600 steps a day necessary to manage with a moderate level of support in a one‐level apartment or home. The declining number of steps taken in the follow‐up period indicated that the UTF subjects might benefit from some special attention paid to their community support needs. These findings are also viewed in the context of limited data available on the extent of walking of non‐amputees.
Changes in bone marrow blood flow with aging
Authors: Kita Kiyoshi , Kawai Kazuo , Hirohata Kazushi 
Published: February 2005

AbstractWe investigated changes in bone marrow blood flow and histology with aging in rabbits. Bone marrow blood flow was measured by the hydrogen washout method, which was performed in the proximal tibia of Japanese white rabbits, 3–42 months of age. Bone marrow blood flow was found to decrease with age. Histological observations of the proximal tibia identified a decrease in the number of osteoblasts and hematopoietic cells, an increase of the number of empty lacunae, a reduction in bone formation rate, and a degeneration of marrow fat with aging. These results suggest that the decrease of bone marrow blood flow is related to histological changes found with aging.