bluuebunny/crossref_metadata_2025_split huggingface dataset:
Collagen orientation in periosteum and perichondrium is aligned with preferential directions of tissue growth
Authors: Foolen Jasper , van Donkelaar Corrinus , Nowlan Niamh , Murphy Paula , Huiskes Rik , Ito Keita 
Published: April 2008

AbstractA feedback mechanism between different tissues in a growing bone is thought to determine the bone's morphogenesis. Cartilage growth strains the surrounding tissues, eliciting alterations of its matrix, which in turn, creates anisotropic stresses, guiding directionality of cartilage growth. The purpose of this study was to evaluate this hypothesis by determining whether collagen fiber directions in the perichondrium and periosteum align with the preferential directions of long bone growth. Tibiotarsi from chicken embryos across developmental stages were scanned using optical projection tomography (OPT) to assess preferential directions of growth at characteristic sites in perichondrium and periosteum. Quantified morphometric data were compared with two‐photon laser‐scanning microscopy images of the three‐dimensional collagen network in these fibrous tissues. The diaphyseal periosteum contained longitudinally oriented collagen fibers that aligned with the preferential growth direction. Longitudinal growth at both metaphyses was twice the circumferential growth. This concurred with well‐developed circumferential fibers, which covered and were partly interwoven with a dominant network of longitudinally oriented fibers in the outer layer of the perichondrium/periosteum at the metaphysis. Toward both articulations, the collagen network of the epiphyseal surface was randomly oriented, and growth was approximately biaxial. These findings support the hypothesis that the anisotropic architecture of the collagen network, detected in periosteum and perichondrium, concurs with the assessed growth directions. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1263–1268, 2008
Correlation of dynamic cartilage contact stress aberrations with severity of instability in ankle incongruity
Authors: Tochigi Yuki , Rudert M. James , McKinley Todd O. , Pedersen Douglas R. , Brown Thomas D. 
Published: April 2008

AbstractJoint instability is presumed to cause abnormality in cartilage contact mechanics, which accumulatively damages the articular surface, leading to osteoarthritis. The purpose of this study was to clarify the effect of instability on dynamic cartilage contact mechanics. Using human ankle cadaver specimens, potentially unstable ankles were modeled by introducing a coronally directed step‐off incongruity of the anterior tibial surface and/or by transecting the anterior talofibular ligament. Specimens were subjected to a duty cycle with quasi‐physiologic stance‐phase motion and loading. AP tibial forces were modulated, causing a controlled, quantifiable ankle subluxation during the duty cycle. Instantaneous changes in local articular contact stresses were continuously measured using a thin, flexible pressure transducer. Tests were repeated while varying the tibial surface condition (anatomic, 1‐mm step‐off, and 2‐mm step‐off), both before and after transection of the anterior talofibular ligament, with various AP force magnitudes, so that situations of various degrees of instability were created for each specimen. Instability events occurred when the step‐off incongruity was introduced, with the abnormality in joint kinematics being greater after ligament transection. Contact stress data revealed that these instability events involved distinctly abrupt increases/decreases in local articular contact stresses, and that the degree of abruptness was correlated nearly linearly with the abnormality in kinematics. The severity of contact stress aberration appeared to be correlated with the degree of instability. Given this linear relationship, even small instability events presumably involve appreciable abnormality in dynamic joint contact mechanics. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1186–1193, 2008
Evaluation of the mechanical properties of posterolateral structures and supporting posterolateral instability of the knee
Authors: Chun Yong‐Min , Kim Sung‐Jae , Kim Hyoung‐Sik 
Published: April 2008

AbstractThe objectives of this study are to evaluate the contributions of the popliteofibular ligament (PFL), the popliteus tendon (PT), and the lateral (fibular) collateral ligament (LCL) to the posterolateral stability of the knee by changing the sequence of selective transection. Twelve fresh‐frozen cadaveric knees were divided into two groups. Group 1 has a cutting sequence as follows: PFL, PT, LCL. Group 2 has a cutting sequence as follows: PT, PFL, LCL. Each specimen was mounted on the apparatuses using the Ilizarov external fixator for measuring external rotatory and varus laxities at every 30° from 0° to 90° of knee flexion. In both groups, there was no significant difference between the PFL and PT in the increment of respective external rotatory laxity after transection at each knee flexion angle, except 0° in group 2. The transection of the LCL significantly increased the external rotation laxity at 0° and 30°. Varus instability was increased significantly only after cutting the LCL at every knee flexion angle. In conclusion, both the PFL and PT equally contribute to the external rotatory stability. The LCL also contributes to the external rotatory stability at early range of knee flexion. The LCL is a main structure for varus stability in the knee. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1371–1376, 2008
Modulation of Na+‐H+ exchange isoforms NHE1 and NHE3 by insulin‐like growth factor‐1 in isolated bovine articular chondrocytes
Authors: Tattersall Amanda L. , Wilkins Robert J. 
Published: April 2008

AbstractIncubation with serum modulates the transporters that regulate intracellular pH (pHi) in articular chondrocytes, upregulating acid extrusion by Na+‐H+ exchange (NHE). There is stimulation of NHE1, together with induction of NHE3 activity. These isoforms exhibit differential responses to components of mechanical load experienced by chondrocytes during joint loading. The identity of the component(s) of serum responsible is unknown. A possibility, however, is insulin‐like growth factor‐1 (IGF‐1), present in normal cartilage and found at enhanced levels in osteoarthritic tissue. In the present study, the effects of IGF‐1 on pHi regulation have been characterized using fluorescence measurements of bovine articular chondrocytes, and the sensitivity of pHi regulation to hyperosmotic shock and raised hydrostatic pressure determined. For cells isolated in the absence of IGF‐1, pHi recovery following acidification was predominantly mediated by NHE1. Recovery was enhanced when cells were incubated for 18 h with 20 ng mL−1 IGF; this effect represented increased acid extrusion by NHE1, supplemented by NHE3 activity. NHE3 activity was not detected in IGF‐1‐treated cells that had been incubated with the protein synthesis inhibitor cycloheximide, although NHE1 activity was unaffected. In the absence of IGF‐1, suspension in hyperosmotic solutions or raised hydrostatic pressure enhanced pHi recovery of acidified cells. This response was missing in cells incubated with IGF‐1. Unresponsiveness to hyperosmotic shock represented inhibition of NHE3 activity, and was prevented using the protein kinase A inhibitor KT5720. For raised hydrostatic pressure, a decrease in NHE1 activity was responsible, and was prevented by the protein kinase C inhibitor chelerythrine. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1428–1433, 2008
Proprioception assessment in subjects with idiopathic loss of shoulder range of motion: Joint position sense and a novel proprioceptive feedback index
Authors: Yang Jing‐Lan , Chen Shiauyee , Jan Mei‐Hwa , Lin Yeong‐Fwu , Lin Jiu‐jenq 
Published: April 2008

AbstractWe examined the effects of elevation range and plane on shoulder joint proprioception in subjects with idiopathic loss of shoulder range of motion (ROM). Joint position sense (JPS) and a novel proprioceptive feedback index (PFI), including difference magnitude and the similarity index, were used to assess proprioception. Twelve subjects (eight male, four female) with involved stiff shoulders and normal opposite shoulders were recruited from a university hospital. Subjects attempted to repeat six target positions. Target positions consisted of arm elevation in three planes (frontal, scapular, and sagittal planes) and two ranges (end/mid range). Six trials of each target position were used to determine acceptable trials for stabilization of the data, less than 5% of the cumulative mean values for at least three successive trials. The data stabilized at the sixth repetition. Compared to control shoulders, involved shoulders had enhanced proprioception during end range movements (p < 0.05). The magnitude of the repositioning error and difference magnitude decreased (1.6°–3.5° for repositioning error and 22.2°–62.1° for difference magnitude), whereas similarity index improved at end range movements compared to mid range movements (p < 0.05) in involved stiff shoulders. Results of JPS and PFI suggest that both capsuloligamentous and musculotendinous mechanoreceptors play an important role in proprioception feedback during active movements in subjects with idiopathic loss of shoulder ROM. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1218–1224, 2008
Complex, multidimensional thumb movements generated by individual extrinsic muscles
Authors: Li Zong‐Ming , Tang Jie , Chakan Matthew , Kaz Rodrigo 
Published: April 2008

AbstractThe objective of this study was to investigate three‐dimensional thumb joint movements produced by individual extrinsic thumb muscles. Ten cadaveric arms were dissected to expose the musculotendinous junctions of the flexor pollicis longus (FPL), abductor pollicis longus (APL), extensor pollicis brevis (EPB), and extensor pollicis longus (EPL). Each muscle/tendon was loaded to 10% of its maximal force capability whereas three‐dimensional angular movements of the carpometacarpal (CMC), metacarpophalangeal (MCP), and interphalangeal (IP) joints were obtained simultaneously. We found that each extrinsic muscle produced unique joint angular trajectories in multiple directions. The FPL, APL, EBP, and EPL generated two, two, three, and six movements, respectively. The extrinsic muscles all together generated eight movements among the multiple thumb joints. High interjoint coordination was shown between the MCP joint flexion and IP joint flexion by FPL loading, as well as between the MCP joint extension and IP joint extension by EPL loading. High intrajoint coordination was observed between extension and supination at the CMC joint by the APL, EPL, and EPB. We concluded that each muscle produces movements in multiple joints and/or in multiple anatomical directions. The findings provide a novel insight into the biomechanical roles of the extrinsic muscles of the thumb. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1289–1295, 2008
Patient‐specific finite element analysis of chronic contact stress exposure after intraarticular fracture of the tibial plafond
Authors: Li Wendy , Anderson Donald D. , Goldsworthy Jane K. , Marsh J. Lawrence , Brown Thomas D. 
Published: April 2008

AbstractThe role of altered contact mechanics in the pathogenesis of posttraumatic osteoarthritis (PTOA) following intraarticular fracture remains poorly understood. One proposed etiology is that residual incongruities lead to altered joint contact stresses that, over time, predispose to PTOA. Prevailing joint contact stresses following surgical fracture reduction were quantified in this study using patient‐specific contact finite element (FE) analysis. FE models were created for 11 ankle pairs from tibial plafond fracture patients. Both (reduced) fractured ankles and their intact contralaterals were modeled. A sequence of 13 loading instances was used to simulate the stance phase of gait. Contact stresses were summed across loadings in the simulation, weighted by resident time in the gait cycle. This chronic exposure measure, a metric of degeneration propensity, was then compared between intact and fractured ankle pairs. Intact ankles had lower peak contact stress exposures that were more uniform and centrally located. The series‐average peak contact stress elevation for fractured ankles was 38% (p = 0.0015; peak elevation was 82%). Fractured ankles had less area with low contact stress exposure than intact ankles and a greater area with high exposure. Chronic contact stress overexposures (stresses exceeding a damage threshold) ranged from near zero to a high of 18 times the matched intact value. The patient‐specific FE models represent substantial progress toward elucidating the relationship between altered contact stresses and the outcome of patients treated for intraarticular fractures. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1039–1045, 2008
Joint capsule mast cells and neuropeptides are increased within four weeks of injury and remain elevated in chronic stages of posttraumatic contractures
Authors: Hildebrand Kevin A. , Zhang Mei , Hart David A. 
Published: April 2008

AbstractThe purpose of this article was to determine mast cell and neuropeptide nerve fiber numbers in joint capsules in posttraumatic contractures, as elevated numbers have been implicated in other fibrotic and contracture conditions. Twelve skeletally mature rabbits had intraarticular cortical windows removed from the medial and lateral femoral condyles and the knee joint immobilized. The contralateral unoperated limb served as a control. Equal numbers of rabbits were sacrificed 4 weeks after surgery or 40 weeks after the first surgery that included 32 weeks of remobilization. Six patients with chronic posttraumatic elbow joint contractures and six age‐matched organ donor controls free of elbow contractures were also studied. Joint capsule myofibroblast, mast cell, and neuropeptide containing nerve fiber numbers were assessed with immunohistochemistry. The numbers of myofibroblasts, mast cells, and neuropeptide containing nerve fibers expressed as a percentage of total cells were significantly greater in the contracture capsules when compared to the control capsules at all time points (p < 0.0001). The range of percentages for the three components in the contracture capsules versus the controls were 41–48% versus 9–10%, 44–50% versus 11–13%, and 45–50% versus 10–12% for the acute and chronic stages of the rabbit model and the chronic stages in the human elbows, respectively. These data support the hypothesis that a myofibroblast–mast cell–neuropeptide fibrosis axis may underlie some of the pathologic changes in the joint capsule in posttraumatic contractures. Approaches designed to manipulate this axis, such as preventing degranulation of mast cells, warrant further investigation. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1313–1319, 2008
Disaster mental health workers responding to ground zero: One year later
Authors: Daly Erin Scott , Gulliver Suzy Bird , Zimering Rose T. , Knight Jeffrey , Kamholz Barbara W. , Morissette Sandra B. 
Published: April 2008

AbstractThe current study examined anniversary reactions in mental health disaster relief workers following traumatic exposure at the site of the World Trade Center terrorist attacks. Despite relatively low levels of symptom reporting, workers endorsed an increase in both negative mood symptoms and functional impairment at the one‐year anniversary of their traumatic exposure (compared to 6 months postexposure). For those individuals who met at least partial criteria for PTSD immediately following exposure, overall self‐reported PTSD symptoms tended to increase from 6 to 12 months. This tendency resulted specifically from an increase in hyperarousal symptoms. Although few endorsed symptoms at clinical levels, our results demonstrate that disaster relief workers may experience an increase in symptomatology at the anniversary of their traumatic exposure.
Accumulated childhood trauma and symptom complexity
Authors: Briere John , Kaltman Stacey , Green Bonnie L. 
Published: April 2008

AbstractThe relationship between accumulated exposure to different types of traumatic events (cumulative trauma) in childhood and the total number of different types of symptomatology reported (symptom complexity) in adulthood was examined in a sample of 2,453 female university students. There was a linear relationship between the number of trauma types experienced by participants before 18 and symptom complexity. This effect remained even when controlling for specific traumatic events, suggesting a generalized effect of cumulative trauma.
Meta‐analysis of alexithymia in posttraumatic stress disorder
Authors: Frewen Paul A. , Dozois David J. A. , Neufeld Richard W. J. , Lanius Ruth A. 
Published: April 2008

AbstractThe authors present a meta‐analysis investigating the prevalence of alexithymia in 12 studies encompassing 1,095 individuals with posttraumatic stress disorder (PTSD). A large effect size was found associating PTSD with alexithymia. Effect sizes were higher in studies of male combat PTSD samples in comparison with studies of other PTSD samples. Clinical and research directions are discussed.
Entering exile: Trauma, mental health, and coping among Tibetan refugees arriving in Dharamsala, India
Authors: Sachs Emily , Rosenfeld Barry , Lhewa Dechen , Rasmussen Andrew , Keller Allen 
Published: April 2008

AbstractEach year thousands of Tibetans escape Chinese‐controlled Tibet. The authors present findings on the experiences, coping strategies, and psychological distress (depression, anxiety, somatization, and posttraumatic stress disorder) of 769 Tibetan refugees arriving in Dharamsala, India (2003–2004). Distress increased significantly with greater trauma exposure. However, despite a high prevalence of potentially traumatizing events, levels of psychological distress were extremely low. Coping activity (primarily religious) and subjective appraisals of trauma severity appeared to mediate the psychological effects of trauma exposure. The potential impact of other variables, including culturally determined attitudes about trauma and timing of assessment, are discussed.
Elevated rates of current PTSD among Hispanic veterans in the NVVRS: True prevalence or methodological artifact?
Authors: Lewis‐Fernández Roberto , Turner J. Blake , Marshall Randall , Turse Nicholas , Neria Yuval , Dohrenwend Bruce P. 
Published: April 2008

AbstractThe elevated rate of current posttraumatic stress disorder (PTSD) among Hispanic Vietnam veterans has been attributed to culturally based expressiveness that inflates symptom self‐reports. To investigate this possibility, the authors conducted three hypothesis‐driven analyses with National Vietnam Veterans Readjustment Study (NVVRS) data from the Structured Clinical Interview for DSM‐III‐R (SCID‐) diagnosed subsample of male Vietnam Theater veterans (N = 260). First, persistence of the Hispanic elevation after adjusting for war‐zone stress exposure initially suggested the effect of greater expressiveness. Second, symptom‐based analyses isolated this effect to the self‐report Mississippi Scale for Combat‐Related PTSD and not to the clinician‐rated SCID interview. Third, objective measures of functioning did not reveal a unique Hispanic pattern of lower impairment associated with current PTSD. These tests suggest that greater Hispanic expressiveness does not account for the Hispanic elevation in current PTSD in the NVVRS SCID‐diagnosed subsample.
Kinetics of omeprazole degradation in the presence of 2‐mercaptoethanol
Authors: Al‐Matar Ali Kh. , El‐Eswed Bassam , Tutunji Maha F. 
Published: April 2008

AbstractThe reactions of omeprazole, a potent proton pump inhibitor, were investigated in the presence of 2‐mercapotoethanol. Reactions were monitored in solutions buffered to pH values ranging from 2.0 to 5.0 using differential pulse polarography at the static mercury drop electrode. First‐order reaction network was proposed for all conversions. It is demonstrated that acid degradation predominates at pH values ∼2–3, whereas the reaction of sulfenic acid with the more nucleophilic thiol becomes prominent at pH values around 4–5. The acidic medium is necessary for the formation of sulfenic acid, the key intermediate believed to be the active inhibitor, but acid also converts this sulfenic acid into other degradation products that are unreactive toward thiol. The present work suggests that acid inhibition may occur at pH values higher than those previously thought. Thus, “highly acidic medium is required to achieve both accumulation and activation of omeprazole in the parietal cell, but less acidic medium is necessary for the reaction of sulfenic acid intermediate with the sulfhydryl groups of cysteine residues of H+/K+‐ATPase proton pump in vivo.” © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 352–358, 2008
Ammonia–dimethylchloramine system: Kinetic approach in an aqueous medium and comparison with the mechanism involving liquid ammonia
Authors: Stephan J. , Pasquet V. , Elkhatib M. , Goutelle V. , Delalu H. 
Published: April 2008

AbstractAfter an exhaustive study of the system ammonia–dimethylchloramine in liquid ammonia, it was interesting to compare the reactivity of this system in liquid ammonia with the same system in an aqueous medium. Dimethylchloramine prepared in a pure state undergoes dehydrohalogenation in an alkaline medium: the principal products formed are N‐methylmethanimine, 1,3,5‐trimethylhexahydrotriazine, formaldehyde, and methylamine. The kinetics of this reaction was studied by UV, GC, and HPLC as a function of temperature, initial concentrations of sodium hydroxide, and chlorinated derivative. The reaction is of the second order and obeys an E2 mechanism (k1 = 4.2 × 10−5 M−1 s−1, ΔH○# = 82 kJ mol−1, ΔS○# = −59 J mol−1 K−1). The oxidation of unsymmetrical dimethylhydrazine by dimethylchloramine involves two consecutive processes. The first step follows a first‐order law with respect to haloamine and hydrazine, leading to the formation of an aminonitrene intermediate (k2 = 150 × 10−5 M−1 s−1). The second step corresponds to the conversion of aminonitrene into formaldehyde dimethylhydrazone at pH 13). This reaction follows a first‐order law (k3 = 23.5 × 10−5 s−1). The dimethylchloramine–ammonia interaction corresponds to a SN2 bimolecular mechanism (k4 = 0.9 × 10−5 M−1 s−1, pH 13, and T = 25°C). The kinetic model formulated on the basis of the above reactions shows that the formation of the hydrazine in an aqueous medium comes under strong competition from the dehydrohalogenation of dimethylchloramine and the oxidation of the hydrazine formed by the original chlorinated derivative. A global model that explains the mechanisms both in an anhydrous and in an aqueous medium was elaborated. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 340–351, 2008