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91.
Hierarchical folding and reorganization of chromosomes are linked to transcriptional changes in cellular differentiation 下载免费PDF全文
Mariano Barbieri Benjamin L Moore Dorothee CA Kraemer Stuart Aitken Sheila Q Xie Kelly J Morris Masayoshi Itoh Hideya Kawaji Ines Jaeger Yoshihide Hayashizaki Piero Carninci Alistair RR Forrest The FANTOM Consortium Colin A Semple Josée Dostie Ana Pombo Mario Nicodemi 《Molecular systems biology》2015,11(12)
92.
Saman Rasoul Jan Paul Ottervanger Jan-Henk E Dambrink Menko-Jan de Boer Jan CA Hoorntje AT Marcel Gosselink Felix Zijlstra Harry Suryapranata Arnoud WJ van't Hof 《BMC cardiovascular disorders》2007,7(1):1-7
Background
We have previously documented significant differences in orthogonal P wave morphology between patients with and without paroxysmal atrial fibrillation (PAF). However, there exists little data concerning normal P wave morphology. This study was aimed at exploring orthogonal P wave morphology and its variations in healthy subjects.Methods
120 healthy volunteers were included, evenly distributed in decades from 20–80 years of age; 60 men (age 50+/-17) and 60 women (50+/-16). Six-minute long 12-lead ECG registrations were acquired and transformed into orthogonal leads. Using a previously described P wave triggered P wave signal averaging method we were able to compare similarities and differences in P wave morphologies.Results
Orthogonal P wave morphology in healthy individuals was predominately positive in Leads X and Y. In Lead Z, one third had negative morphology and two-thirds a biphasic one with a transition from negative to positive. The latter P wave morphology type was significantly more common after the age of 50 (P < 0.01). P wave duration (PWD) increased with age being slightly longer in subjects older than 50 (121+/-13 ms vs. 128+/-12 ms, P < 0.005). Minimal intraindividual variation of P wave morphology was observed.Conclusion
Changes of signal averaged orthogonal P wave morphology (biphasic signal in Lead Z), earlier reported in PAF patients, are common in healthy subjects and appear predominantly after the age of 50. Subtle age-related prolongation of PWD is unlikely to be sufficient as a sole explanation of this finding that is thought to represent interatrial conduction disturbances. To serve as future reference, P wave morphology parameters of the healthy subjects are provided. 相似文献93.
Hedley CA Emsley Craig J Smith Carole M Gavin Rachel F Georgiou Andy Vail Elisa M Barberan Karen Illingworth Sylvia Scarth Vijitha Wickramasinghe Margaret E Hoadley Nancy J Rothwell Pippa J Tyrrell Stephen J Hopkins 《BMC neurology》2007,7(1):1-12
Background
As critical mediators of local and systemic inflammatory responses, cytokines are produced in the brain following ischaemic stroke. Some have been detected in the circulation of stroke patients, but their role and source is unclear. Focusing primarily on interleukin(IL)-1-related mechanisms, we serially measured plasma inflammatory markers, and the production of cytokines by whole blood, from 36 patients recruited within 12 h and followed up to 1 year after acute ischaemic stroke (AIS).Results
Admission plasma IL-1 receptor antagonist (IL-1ra) concentration was elevated, relative to age-, sex-, and atherosclerosis-matched controls. IL-1β, soluble IL-1 receptor type II, tumour necrosis factor (TNF)-α, TNF-RII, IL-10 and leptin concentrations did not significantly differ from controls, but peak soluble TNF receptor type I (sTNF-RI) in the first week correlated strongly with computed tomography infarct volume at 5–7 days, mRS and BI at 3 and 12 months. Neopterin was raised in patients at 5–7 d, relative to controls, and in subjects with significant atherosclerosis. Spontaneous IL-1β, TNF-α and IL-6 gene and protein expression by blood cells was minimal, and induction of these cytokines by lipopolysaccharide (LPS) was significantly lower in patients than in controls during the first week. Minimum LPS-induced cytokine production correlated strongly with mRS and BI, and also with plasma cortisol.Conclusion
Absence of spontaneous whole blood gene activation or cytokine production suggests that peripheral blood cells are not the source of cytokines measured in plasma after AIS. Increased plasma IL-1ra within 12 h of AIS onset, the relationship between sTNF-RI and stroke severity, and suppressed cytokine induction suggests early activation of endogenous immunosuppressive mechanisms after AIS. 相似文献94.
Yuansha Chen Peter Bystricky Jacob Adeyeye Pinaki Panigrahi Afsar Ali Judith A Johnson CA Bush JG MorrisJr OC Stine 《BMC microbiology》2007,7(1):20
Background
In V. cholerae, the biogenesis of capsule polysaccharide is poorly understood. The elucidation of capsule structure and biogenesis is critical to understanding the evolution of surface polysaccharide and the internal relationship between the capsule and LPS in this species. V. cholerae serogroup O31 NRT36S, a human pathogen that produces a heat-stable enterotoxin (NAG-ST), is encapsulated. Here, we report the covalent structure and studies of the biogenesis of the capsule in V. cholerae NRT36S. 相似文献95.
96.
Daniel D. Carson Mary M. Desouza E. Gloria C. Regisford 《BioEssays : news and reviews in molecular, cellular and developmental biology》1998,20(7):577-583
Embryo implantation is a complex series of events that involves changes in pattern of expression of embryonic as well as uterine cell surface components. In the case of the embryo, these changes are driven by the developmental program. In the case of the uterus, these changes are triggered by both maternal hormonal influences as well as embryo-derived factors. Aspects of the implantation process vary among species; however, interaction between the external surface of the embryonic trophectoderm and the apical surface of the lumenal uterine epithelium is a common event. Progress is being made in defining the molecular players in these cell surface interactions. Large-molecular-weight mucin glycoproteins such as MUC1 are present at the apical surface of the uterine epithelium under most conditions. Under most circumstances, these mucins appear to protect the mucosal surface from infection and the action of degradative enzymes. These mucins are antiadhesive and also appear to represent a barrier to embryo attachment. Consistent with this model, reduction of mucin expression is observed in uterine lumenal epithelia in many species. Nonetheless, mucin expression persists in the human uterus during the proposed receptive phase. It is possible that mucin loss is localized to implantation sites in humans. Alternatively, mucins may function differently within the context of human implantation than in other species. Studies primarily performed in mice indicate that heparan sulfate proteoglycans, in particular, perlecan, appears on the exterior trophectodermal surface coincident with the acquisition of attachment competence. Various in vitro studies indicate that heparan sulfate proteoglycans support embryo attachment activity that may represent an early event in embryo–uterine interaction. Uterine epithelia cells express several complementary heparan sulfate-binding proteins that may participate in these attachment processes. Use of molecular genetic approaches in mouse models, as well as careful studies of the expression and function of these molecules in the context of implantation in various species are beginning to shed light on the key molecular events of implantation. BioEssays 20 :577–583, 1998. © 1998 John Wiley & Sons Inc. 相似文献
97.
98.
Principal component models for sparse functional data 总被引:5,自引:0,他引:5
99.
入侵种喜旱莲子草和莲子草的营养生长和光合作用对温度的响应 总被引:2,自引:0,他引:2
比较温度对入侵种喜旱莲子草(Alternantheraphiloxeroides(Mart.)Griseb.)和其本土近缘种莲子草(A.sessilis(L.)DC.)的营养生长、叶片光合作用及叶绿素荧光的影响。实验将生长均衡的这两种植物放在不同温度(10℃、15℃、20℃、25℃、30℃)的光照培养箱中处理28d。结果表明,喜旱莲子草营养生长的速率和对温度的响应明显不同于莲子草:前者主茎生长的有效积温明显低于后者,分别是11.6d℃和27.0d℃;而新叶萌发的有效积温高于后者,分别是12.1d℃和6.7d℃。入侵种主茎和叶的发育起点温度都比本土种低,分别是10.4℃、11.0℃和12.8℃、14.9℃,表明喜旱莲子草的发育对低温反应不及莲子草敏感。对两种植物叶片的光合作用和叶绿素荧光的测定结果还表明:入侵种比本土种有较高的最大净光合速率和光饱和点,尤其在25℃时;10-30℃的温度范围内喜旱莲子草的最大光化学效率Fv/Fm没有显著变化,而莲子草在10℃低温条件下Fv/Fm值显著降低。较快的主茎生长速率、较宽的温度适应范围以及较高的光合能力可能使喜旱莲子草比本地种具有更强的竞争力,从而在其入侵过程中起了重要作用。 相似文献
100.
玉米叶片生长部位渗透调节和生长的生物物理参数变化 总被引:6,自引:0,他引:6
玉米叶片生长部位随着水分胁迫加剧ψ_w降低、LER减慢。LER从最大到零,快速干旱处理的ψw从-0.55降至-0.85 MPa;缓慢干旱处理ψ_w从-0.88降至-1.13 MPa。在任何一种LER下,缓慢干旱处理的ψ_s比快速干旱处理更低,生长停止时,前者为-1.57 MPa,而后者为-1.30MPa。缓慢干旱叶片尽管在更低ψ_w下,仍能维持一定膨压,保持一定的生长速率。经历长时间水分胁迫会改变细胞延伸生长的生物物理参数,增大临界膨压(0.08~0.09 MPa)。这是水分胁迫植株,在一定ψ_p下生长速率减慢的原因。 相似文献