共查询到20条相似文献,搜索用时 15 毫秒
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Veit B 《Plant molecular biology》2006,60(6):793-810
The essential nature of meristematic tissues is addressed with reference to conceptual frameworks that have been developed
to explain the behaviour of animal stem cells. Comparisons are made between different types of plant meristems with the objective
of highlighting common themes that might illuminate underlying mechanisms. A more in depth comparison of the root and shoot
apical meristems is made which suggests a common mechanism for maintaining stem cells. The relevance of organogenesis to stem
cell maintenance is discussed, along with the nature of underlying mechanisms which help ensure that stem cell production
is balanced with the depletion of cells through differentiation. Mechanisms that integrate stem cell behaviour in the whole
plant are considered, with a focus on the roles of auxin and cytokinin. The review concludes with a brief discussion of epigenetic
mechanisms that act to stabilise and maintain stem cell populations. 相似文献
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《Gender Medicine》2012,9(2):129-136
BackgroundMesenchymal stem cell (MSC) therapy has the potential to enhance muscular regeneration. In previous publications, our group was able to show a dose-response relationship in female animals between the amount of transplanted cells and muscle force. The impact of sex on the regeneration of musculoskeletal injuries following MSC transplantation remains unclear.ObjectiveWe investigated histologic and biomechanical regeneration parameters in rats after autologous transplantation of MSCs. Our hypothesis was that female rats have greater muscle regeneration potential than male rats after autologous MSC transplantation.MethodsThirty-six Sprague-Dawley rats received an open crush trauma of the left soleus muscle. One week after trauma, 2.5 × 106 autologous MSCs, harvested from tibial biopsies, were transplanted locally (female, n = 9; male, n = 9). Control animals received saline solution (female, n = 9; male, n = 9). Histologic analysis and biomechanical evaluation by in vivo muscle force measurement were performed 3 weeks after transplantation.ResultsMSC therapy improved the force of the injured soleus in male rats significantly (twitch: treated, 0.76 [0.51–1.15]; twitch: untreated, 0.45 [0.32–0.73] [P = 0.01]; tetany: treated, 0.63 [0.4–1.21], tetany: untreated, 0.34 [0.16–0.48] [P = 0.04]). Force measurements in females also revealed significant improvements (twitch: treated, 0.71 [0.38–0.96]; twitch: untreated, 0.36 [0.18–0.63] [P = 0.005]; tetany: treated, 0.53 [0.21–0.68]; tetany: untreated, 0.27 [0.11–0.47] [P = 0.01]). The intersexual comparison of fast twitch and tetanic contraction forces revealed no significance (twitch, P = 0.55; tetany, P = 0.19). The histologic analysis showed no differences in the amount of fibrotic tissue (male, P = 0.9; female, P = 0.14) and the size of muscle area (male, P = 0.2; female, P = 0.56) following treatment. Male animals showed higher values for muscle area (P = 0.011) and less fibrosis (P = 0.028), independent of treatment.ConclusionThe outcome of skeletal muscle regeneration after injury can be improved in animals of both sexes with MSC transplantation. 相似文献
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《Cell cycle (Georgetown, Tex.)》2013,12(5):417-418
Recently, we describe a biological role for endogenous CD45+ stem cells in maintaining muscle integrity by participating in regeneration. Our experiments further establish that Wnt-signaling is the mechanism by which resident CD45+ adult stem cells are induced to undergo myogenic specification during muscle regeneration. Importantly, our study suggests that targeting the Wnt-pathway represents a promising therapeutic approach for the treatment of neuromuscular degenerative diseases. 相似文献
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Association of Interleukin-6, Interleukin-12, and Interleukin-10 Gene Polymorphisms with Essential Hypertension in Tatars from Russia 总被引:1,自引:0,他引:1
Essential hypertension is a common disease with fatal clinical complications. Epidemiological and family studies have confirmed
the role of genetic predisposition in its development. Hypertensive patients have been shown to have an altered profile of
pro- and anti-inflammatory cytokines. The aim of our investigation was to reveal the association of interleukin-6, interleukin-12,
and interleukin-10 gene polymorphisms with essential hypertension and its clinical complications in a Tatar ethnic group from
Bashkortostan, Russia. The study involved 362 hypertensive patients and 244 healthy subjects from this Tatar ethnic group
(Bashkortostan, Russia). DNA was isolated from whole venous blood using phenol–chloroform extraction by the standard method.
IL6 −572 G/C, IL12B 1159 C/A, and IL10 –627 C/A genotypes were typed using polymerase chain reaction followed by restriction enzyme digestion. We found that the IL10 −627 *C/*C genotype was associated with decreased risk of hypertension (OR = 0.64, P = 0.035). IL6 genotypes and allele distribution did not differ significantly between subjects with and without hypertension, but the IL6 −572 *G/*G genotype frequency was found to be significantly higher among those patients who had stroke, compared with normotensive control
subjects (P = 0.036). Carriers of the IL12B 1159 *A/*A genotype had a lower risk of stroke (OR = 0.38, P = 0.028). Our study has shown the association between IL10 −627 C/A polymorphism and essential hypertension in the Tatar ethnic group from Bashkortostan, Russia. The IL10 −627*C/*C genotype was found to be protective against hypertension. We also demonstrated that hypertensive patients with the IL12B *A/*A and IL6 *G/*G genotypes had increased risk of stroke. Our results suggest a role for cytokines in cardiovascular disease development in
the Tatar ethnic group, but further investigation is needed. 相似文献
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《Cell reports》2020,30(10):3583-3595.e5
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D.A. Smith 《Biophysical journal》2009,96(9):3682-3691
Most striated muscles generate steady contractile tension when activated, but some preparations, notably cardiac myocytes and slow-twitch fibers, may show spontaneous oscillatory contractions (SPOC) at low levels of activation. We have provided what we believe is new evidence that SPOC is a property of the contractile system at low actin-myosin affinity, whether caused by a thin-filament regulatory system or by other means. We present a quantitative single-sarcomere model for isotonic SPOC in skeletal muscle with three basic ingredients: i), actin and myosin filaments initially in partial overlap, ii), stretch activation by length-dependent changes in the lattice spacing, and iii), viscoelastic passive tension. Modeling examples are given for slow-twitch and fast-twitch fibers, with periods of 10 s and 4 s respectively. Isotonic SPOC occurs in a narrow domain of parameter values, with small minimum and maximum values for actin-myosin affinity, a minimum amount of passive tension, and a maximum transient response rate that explains why SPOC is favored in slow-twitch fibers. The model also predicts the contractile, relaxed and SPOC phases as a function of phosphate and ADP levels. The single-sarcomere model can also be applied to a whole fiber under auxotonic and fixed-end conditions if the remaining sarcomeres are treated as a viscoelastic load. Here the model predicts an upper limit for the load stiffness that leads to SPOC; this limit lies above the equivalent loads expected from the rest of the fiber. 相似文献
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Ludovic Vallier Thomas Touboul Zhenzhi Chng Minodora Brimpari Nicholas Hannan Enrique Millan Lucy E. Smithers Matthew Trotter Peter Rugg-Gunn Anne Weber Roger A. Pedersen 《PloS one》2009,4(6)
Human embryonic stem cells have unique value for regenerative medicine, as they are capable of differentiating into a broad variety of cell types. Therefore, defining the signalling pathways that control early cell fate decisions of pluripotent stem cells represents a major task. Moreover, modelling the early steps of embryonic development in vitro may provide the best approach to produce cell types with native properties. Here, we analysed the function of key developmental growth factors such as Activin, FGF and BMP in the control of early cell fate decisions of human pluripotent stem cells. This analysis resulted in the development and validation of chemically defined culture conditions for achieving specification of human embryonic stem cells into neuroectoderm, mesendoderm and into extra-embryonic tissues. Importantly, these defined culture conditions are devoid of factors that could obscure analysis of developmental mechanisms or render the resulting tissues incompatible with future clinical applications. Importantly, the growth factor roles defined using these culture conditions similarly drove differentiation of mouse epiblast stem cells derived from post implantation embryos, thereby reinforcing the hypothesis that epiblast stem cells share a common embryonic identity with human pluripotent stem cells. Therefore the defined growth factor conditions described here represent an essential step toward the production of mature cell types from pluripotent stem cells in conditions fully compatible with clinical use ant also provide a general approach for modelling the early steps of mammalian embryonic development. 相似文献
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Barbora de Courten Timea Kurdiova Maximilian P. J. de Courten Vitazoslav Belan Inge Everaert Marek Vician Helena Teede Daniela Gasperikova Giancarlo Aldini Wim Derave Jozef Ukropec Barbara Ukropcova 《PloS one》2015,10(10)
BackgroundCarnosine is a naturally present dipeptide abundant in skeletal muscle and an over-the counter food additive. Animal data suggest a role of carnosine supplementation in the prevention and treatment of obesity, insulin resistance, type 2 diabetes and cardiovascular disease but only limited human data exists.ConclusionOur data shows that higher carnosine content in human skeletal muscle is positively associated with insulin resistance and fasting metabolic preference for glucose. Moreover, it is negatively associated with HDL-cholesterol and basal energy expenditure. Intervention studies targeting insulin resistance, metabolic and cardiovascular disease risk factors are necessary to evaluate its putative role in the prevention and management of type 2 diabetes and cardiovascular disease. 相似文献
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《Cell communication & adhesion》2013,20(1-2):9-17
AbstractThe traditional classification of signalling in biological systems is insufficient and outdated and novel efforts must take into account advances in systems theory, information theory and linguistics. We present some of the classification systems currently used both within and outside of the biological field and discuss some specific aspects of the nature of signalling in tissue development. The analytical methods used in understanding non-biological networks provide a valuable vocabulary, which requires integration and a system of classification to further facilitate development. 相似文献
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Background
The fully differentiated progeny of ES cells (ESC) may eventually be used for cell replacement therapy (CRT). However, elements of the innate immune system may contribute to damage or destruction of these tissues when transplanted.Methodology/Principal Findings
Herein, we assessed the hitherto ill-defined contribution of the early innate immune response in CRT after transplantation of either ESC derived insulin producing cell clusters (IPCCs) or adult pancreatic islets. Ingress of neutrophil or macrophage cells was noted immediately at the site of IPCC transplantation, but this infiltration was attenuated by day three. Gene profiling identified specific inflammatory cytokines and chemokines that were either absent or sharply reduced by three days after IPCC transplantation. Thus, IPCC transplantation provoked less of an early immune response than pancreatic islet transplantation.Conclusions/Significance
Our study offers insights into the characteristics of the immune response of an ESC derived tissue in the incipient stages following transplantation and suggests potential strategies to inhibit cell damage to ensure their long-term perpetuation and functionality in CRT. 相似文献20.
Ninette Amariglio Abraham Hirshberg Bernd W Scheithauer Yoram Cohen Ron Loewenthal Luba Trakhtenbrot Nurit Paz Maya Koren-Michowitz Dalia Waldman Leonor Leider-Trejo Amos Toren Shlomi Constantini Gideon Rechavi 《PLoS medicine》2009,6(2)