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91.
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The histone demethylase, lysine (K)-specific demethylase 2A (Kdm2a), is highly conserved and expressed ubiquitously. Kdm2a can regulate cell proliferation and osteo/dentinogenic, adipogenic and chondrogenic differentiation of mesenchymal stem cells (MSCs) derived from dental tissue. We used quantitative real-time RT-PCR analysis and immunohistochemistry to detect Kdm2a expression during development of the murine molar at embryonic days E12, E14, E16 and E17 and postnatal days P3 and P14. Immunohistochemistry results showed no positive staining of Kdm2a at E12. At E14, Kdm2a was expressed weakly in the inner enamel epithelium, stellate reticulum cells and dental sac. At E16, Kdm2a was expressed mainly in the inner and outer enamel epithelium, stratum intermedium and dental sac, but weaker staining was found in cervical loop and dental papilla cells adjacent to the basement membrane. At E17, the strongest Kdm2a staining was detected in the ameloblasts and stronger Kdm2a staining also was detected in the stratum intermedium, outer enamel epithelium and dental papilla cells compared to the expression at E16. Postnatally, we found that Kdm2a was localized in secretory and mature ameloblasts and odontoblasts, and dentin was unstained. Real-time RT-PCR showed that Kdm2a mRNA levels in murine germ cells increased from E12 to E14 and from E14 to E16; no significant change occurred at E16, E17 or P3, then the levels decreased at P14 compared to P3. Kdm2a expression may be closely related to cell proliferation, to ameloblast and odontoblast differentiation and to the secretion of extracellular enamel and dentin during murine tooth development. 相似文献
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Joseph A. Zeni Katherine Rudolph Jill S. Higginson 《Journal of electromyography and kinesiology》2010,20(1):148-154
Altered muscle coordination strategies in persons with knee osteoarthritis (OA) result in an increase in co-contraction of the quadriceps and hamstrings during walking. While this may increase intersegmental joint contact force and expedite disease progression, it is not currently known whether the magnitude of co-contraction increases with a progressive loss of joint space or whether the level of co-contraction is dependent on walking speed. The purposes of this study were to (1) determine if co-contraction increased with OA severity and (2) discern whether differences in co-contraction were a result of altered freely chosen walking speeds or rather an inherent change associated with disease progression. Forty-two subjects with and without knee osteoarthritis were included in the study. Subjects were divided into groups based on disease severity. When walking at a controlled speed of 1.0 m/s, subjects with moderate and severe knee OA showed significantly higher co-contraction when compared to a healthy control group. At freely chosen walking speeds only the moderate OA group had significantly higher co-contraction values. Increased walking speed also resulted in a significant increase in co-contraction, regardless of group. The results of this study demonstrate that persons with knee OA develop higher antagonistic muscle activity. This occurs despite differences in freely chosen walking speed. Although subjects with OA had higher co-contraction than the control group, co-contraction may not increase with disease severity. 相似文献
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The purpose of this study was to quantify how the predicted muscle function would change in a muscle-driven forward simulation of normal walking when changing the number of degrees of freedom in the model. Muscle function was described by individual muscle contributions to the vertical acceleration of the center of mass (COM). We built a two-dimensional (2D) sagittal plane model and a three-dimensional (3D) model in OpenSim and used both models to reproduce the same normal walking data. Perturbation analysis was applied to deduce muscle function in each model. Muscle excitations and contributions to COM support were compared between the 2D and 3D models. We found that the 2D model was able to reproduce similar joint kinematics and kinetics patterns as the 3D model. Individual muscle excitations were different for most of the hip muscles but ankle and knee muscles were able to attain similar excitations. Total induced vertical COM acceleration by muscles and gravity was the same for both models. However, individual muscle contributions to COM support varied, especially for hip muscles. Although there is currently no standard way to validate muscle function predictions, a 3D model seems to be more appropriate for estimating individual hip muscle function. 相似文献
97.
Victoria Simms Nancy Gikaara Grace Munene Mackuline Atieno Jeniffer Kataike Clare Nsubuga Geoffrey Banga Eve Namisango Suzanne Penfold Peter Fayers Richard A. Powell Irene J. Higginson Richard Harding 《PloS one》2013,8(2)
Objectives
We aimed to determine for the first time the prevalence and severity of multidimensional problems in a population newly diagnosed with HIV at outpatient clinics in Africa.Methods
Recently diagnosed patients (within previous 14 days) were consecutively recruited at 11 HIV clinics in Kenya and Uganda. Participants completed a validated questionnaire, the African Palliative Outcome Scale (POS), with three underpinning factors. Ordinal logistic regression was used to evaluate risk factors for prevalence and severity of physical, psychological, interpersonal and existential problems.Results
There were 438 participants (62% female, 30% with restricted physical function). The most prevalent problems were lack of help and advice (47% reported none in the previous 3 days) and difficulty sharing feelings. Patients with limited physical function reported more physical/psychological (OR = 3.22) and existential problems (OR = 1.54) but fewer interpersonal problems (OR = 0.50). All outcomes were independent of CD4 count or ART eligibility.Conclusions
Patients at all disease stages report widespread and burdensome multidimensional problems at HIV diagnosis. Newly diagnosed patients should receive assessment and care for these problems. Effective management of problems at diagnosis may help to remove barriers to retention in care. 相似文献98.
99.
Chand T. John Frank C. Anderson Jill S. Higginson 《Computer methods in biomechanics and biomedical engineering》2013,16(4):451-462
A fundamental question in movement science is how humans perform stable movements in the presence of disturbances such as contact with objects. It remains unclear how the nervous system, with delayed responses to disturbances, maintains the stability of complex movements. We hypothesised that intrinsic muscle properties (i.e. the force–length–velocity properties of muscle fibres and tendon elasticity) may help stabilise human walking by responding instantaneously to a disturbance and providing forces that help maintain the movement trajectory. To investigate this issue, we generated a 3D muscle-driven simulation of walking and analysed the changes in the simulation's motion when a disturbance was applied to models with and without intrinsic muscle properties. Removing the intrinsic properties reduced the stability; this was true when the disturbing force was applied at a variety of times and in different directions. Thus, intrinsic muscle properties play a unique role in stabilising walking, complementing the delayed response of the central nervous system. 相似文献
100.
Wei Gao Martin Gulliford Michael I. Bennett Fliss E. M. Murtagh Irene J. Higginson 《PloS one》2014,9(1)