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排序方式: 共有451条查询结果,搜索用时 46 毫秒
441.
442.
Natalia N. Nalivaeva Lilia Fisk Rosa M. Canet. Aviles Svetlana A. Plesneva Igor A. Zhuravin Anthony J. Turner 《International journal of peptide research and therapeutics》2003,10(5-6):455-462
Summary In the present study we have investigated the effect of prenatal hypoxia on expression of amyloid precursor protein (APP)
and some metallopeptidases, which regulate β-amyloid peptide (Aβ) levels (neprilysin (NEP) and endothelin-converting enzyme
(ECE-1)) in the cortex of rats during different periods of postnatal development. We have found that the level of APP in the
sensorimotor cortex (SMC) of rats, analysed by Western blotting, increases from days 1 to 5 of postnatal development and then
steadily decreases with age, with the most dramatic decline in the period from day 180 to 600. In the cortex of rats subjected
to prenatal hypoxia on day 13.5 of embryogenesis, the postnatal levels of APP were higher than in the control. Secretion of
the soluble form of APP (sAPP) by α-secretase was found to be the most active on day 30 of postnatal development and there
was a significant decrease in the production of sAPP after prenatal hypoxia. NEP was found to be expressed in the cortex of
rats only at the early stages of postnatal development and it was barely detectable in adult rats. The decline of NEP levels
during ageing might contribute to accumulation of Aβ in later life in humans. Prenatal hypoxia resulted in a significant decrease
of NEP expression on day 10, but its level was recovered when animals were preconditioned to mild hypoxia. A similar phenomenon
was observed when the expression of ECE-1 was analysed. Overall, prenatal hypoxia leads to significant changes in the levels
of APP and expression of metallopeptidases involved in amyloid metabolism during all postnatal life and preconditioning to
hypoxia appeared to be neuroprotective. 相似文献
443.
Cellular hypoxic preconditioning is being employed to obtain complex, yet physiological, secretomes rich is angiogenic factors. We previously proposed exposing peripheral blood cells (PBCs) to hypoxic stress stimulation, and demonstrated that controlled release of PBC-derived factor mixtures induces directional microvessel growth in vitro. Hypoxia therefore provides a useful tool for enhancing the angiogenic potential of blood plasma, by generating compositions based on PBCs' natural responses to a wound-like microenvironment. Here, we discuss various methods for preparing and delivering Hypoxia Preconditioned Plasma (HPP), i.e., plasma derived after extracorporeal conditioning of anticoagulated blood under physiological temperature and hypoxia. Special emphasis is given to those approaches that will likely facilitate the clinical translation of HPP-based therapies. We finally draw a comparison between HPP and other, currently available blood-based products, and present the case that its arrival paves the way for developing next-generation autologous therapies toward angiogenesis-supported tissue repair and regeneration. 相似文献
444.
Emanuela Fragonas Piero Pollesello Vladimir Mlinárik Renato Toffanin Cristina Grando Cristiana Godeas Franco Vittur 《Biochimica et Biophysica Acta (BBA)/General Subjects》1998,1425(1):103-111
Vascular invasion of calcified cartilage, during endochondral ossification, is initiated and sustained by invasive cells (endothelial cells and macrophages) which degrade the tissue by releasing lytic enzymes. Concurrently, reactive oxygen species (ROS) are also released by these cells and we hypothesize that ROS also contribute to the degradation of the tissue. As a preliminary approach to this problem, the antioxidant activities and the effect of ROS on hypertrophic cartilage and chondrocytes (HCs) were investigated. Compared to resting or articular chondrocytes, HCs exhibited higher catalase but lower SOD specific activities and lower PHGPx concentration, thus revealing a defence activity specific against H2O2. Moreover, dose-dependent depletion of ATP occurred after few minutes of exposure to ROS, and a long-term treatment (16 h incubation with ROS) promoted the release of LDH activity and a significant variation of the poly- to mono-unsaturated fatty acid ratio. Finally, the incubation of HCs with low ROS doses induced the release of sedimentable alkaline phosphatase activity (matrix vesicles). How the obtained results fit the in vivo occurring events is discussed. 相似文献
445.
446.
摘要 目的:寻找可作为肥厚性硬脑膜炎(hypertrophic pachymeningitis, HP)炎性标志物的外周血炎性指标及炎性复合指标。方法:纳入2015年4月至2019年12月期间在北京同仁医院神经内科住院治疗的17例HP患者,对其临床资料、影像学及实验室检查等进行回顾性归纳分析。统计HP最常见症状及首发症状,并对出院不同预后患者的临床资料进行比较。随后纳入32例与HP无明确相关性的其他神经系统非炎性疾病患者(non-inflammatory neurological diseases,OND)作为对照,分析两组外周血炎性指标及炎性复合指标之间差异,找寻在两组间具有鉴别诊断意义的炎性指标及炎性复合指标。结果:纳入HP患者平均年龄为50±16岁,男女比10:7。其中特发性HP 10例,继发性HP 7例。最常见症状为复视(12例),其次是头痛(10例)。最常见首发症状亦为复视(7例)。HP患者脑脊液白细胞数及蛋白水平正常。随访中发现原发性HP与继发性HP预后无差异。HP组和OND组除外周血类风湿因子(rheumatoid factors,RF)、红细胞沉降率(erythrocyte sedimentation rate,ESR)具有统计学差异外(P<0.05),中性粒细胞与淋巴细胞比值(neutrophil to lymphocyte ratio, NLR)这一炎性复合指标亦存在统计学差异(P<0.05)。同时发现上述三指标中ESR联合NLR对HP的排除诊断具有较高特异性。结论:HP按病因分为特发性和继发性。其临床表现多样,本组患者以复视为主要及首发症状,其次为头痛。本研究新发现炎性复合指标NLR在HP中升高且提示外周血急性炎症状态。同时,ESR会同NLR对该病的排除诊断具有重要意义。但炎性指标和炎性复合指标对于预后判断尚有待扩大样本量进一步研究。 相似文献
447.
Fibronectin (FN) in hypertrophic scars and keloids 总被引:2,自引:0,他引:2
Summary Fibronectin (FN) distribution was compared among samples of normal human dermis, hypertrophic scar, keloid, and granulation tissues from deep injuries. Localization was established by use of fibronectin antibodies and the indirect immunofluorescence method. Fresh-frozen tissue was sectioned on a cryostat and examined by epifluorescence. Hypertrophic scar and keloid demonstrated heavy deposition of FN, which conformed to the nodular characteristics of the lesions. Intense localization occurred in granulation tissue over fibroblasts which were stellate and vesiculated, and over small blood vessels. FN-staining was weak in areas over fibroblasts which were more rounded and nonvesiculated. Staining for FN was also minimal over the collagen in normal dermis and the deeper, larger collagen fascicles in the lesions. Fibroblasts cultured from normal dermis, hypertrophic scar, and keloid for 5–6 weeks were intensely stained for FN. Extracellular matrix was heavily positive in cultures from the lesions compared with those from normal dermis.Supported in part by NIH Research Grant 1 R01GM 25159 相似文献
448.
Marta H. G. Costa Margarida S. Costa Beatriz Painho Carolina D. Sousa Inês Carrondo Enrique Oltra Beatriz Pelacho Felipe Prosper Inês A. Isidro Paula Alves Margarida Serra 《Biotechnology and bioengineering》2023,120(9):2725-2741
Extracellular vesicles (EVs) derived from mesenchymal stromal cells (MSCs) act as signaling mediators of cellular responses. However, despite representing a promising alternative to cell-based therapies, clinical translation of EVs is currently limited by their lack of scalability and standardized bioprocessing. Herein, we integrated scalable downstream processing protocols with standardized expansion of large numbers of viable cells in stirred-tank bioreactors to improve EV production. Higher EV yields were linked to EV isolation by tangential flow filtration followed by size exclusion chromatography, rendering 5 times higher number of EVs comparatively to density gradient ultracentrifugation protocols. Additionally, when compared to static culture, EV manufacture in bioreactors resulted in 2.2 higher yields. Highlighting the role of operating under optimal cell culture conditions to maximize the number of EVs secreted per cell, MSCs cultured at lower glucose concentration favored EV secretion. While offline measurements of metabolites concentration can be performed, in this work, Raman spectroscopy was also applied to continuously track glucose levels in stirred-tank bioreactors, contributing to streamline the selection of optimal EV collection timepoints. Importantly, MSC-derived EVs retained their quality attributes and were able to stimulate angiogenesis in vitro, therefore highlighting their promising therapeutic potential. 相似文献
449.
450.
《Indian pacing and electrophysiology journal》2021,21(6):367-393
In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consensus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology (ACC), and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate CIED follow-up in pediatric patients. 相似文献