Microscopic overview of crinoid regeneration.

Crinoids are well known for their striking regenerative potential and can rapidly and completely regenerate arms lost following self-induced or traumatic amputation. Thus they provide a valuable experimental model for investigation of the regenerative process from the macroscopic to the molecular level. In these last years we have studied in detail the overall process of arm regeneration in the comatulid Antedon mediterranea. This phenomenon can be described on the whole as a typical blastemal regeneration in which new structures develop from migratory pluripotential, actively proliferating cells in the presence of presumptive regulatory factors. The overall process can be subdivided into three main phases: a repair phase, an early regenerative phase, and an advanced regenerative phase, whose crucial aspects are related to common fundamental mechanisms such as cell migration and proliferation, intervention of stem cells and/or dedifferentiated cells, contribution of putative growth factors, particularly in terms of specific neurally derived factors, and mechanisms of pattern formation. This article focuses on the main aspects of the phenomenon and gives a brief account of the most recent and relevant results. Our approach employs classical methods of light (LM) and electron (TEM and SEM) microscopy, immunocytochemistry, and histofluorescence on experimentally induced arm regenerations of standard or abnormal type obtained in significantly different experimental conditions, including extreme mutilations (explants) or exposure to pseudo-estrogenic environmental contamination.     

Regeneration in echinoderm larvae.

The ability of echinoderms to regenerate missing body parts has been a subject of interest to scientists for many years. Asexual reproduction (by fission or budding) is a phenomenon that involves regeneration of missing structures. Although asexual reproduction and regeneration have been the focus of many studies in adult echinoderms, there have been comparatively fewer studies examining these phenomena in echinoderm larvae, and most of these have been conducted in the last few years. In this article we review regeneration in larval echinoderms. We also discuss larval asexual reproduction.     

Fossil record of echinoderm regeneration with special regard to crinoids.

Regeneration of skeletal parts of fossil echinoderms is reviewed. Among regenerations of various fossil echinoderms, those of crinoids are most common and many examples have been reported. Mesozoic and Cenozoic crinoids, the subclass Articulata, are characterized by the dominance of muscular articulations in the arms and they have only a small number of ligamentary articulations in localized positions that are specialized for autotomy. The dominance of muscular articulations is most conspicuous in the family Isocrinidae and comatulid (stalkless) crinoids. Most of the regenerated arms of articulate crinoids start on this ligamentary articulation. In contrast, most Paleozoic crinoids have many more ligamentary articulations and fewer muscular articulations in their arms than the Mesozoic to Recent crinoids. The ligamentary articulations of Paleozoic crinoids were probably not capable of autotomy. Fossil and recent stalked crinoids provide data on the degree and style of regeneration after loss of body parts. If the aboral nerve center in the basal part of crown is retained, the entire calyx and arms can be regenerated. In contrast, if the aboral nerve center is lost and only the stalk is preserved, some skeletal parts can only be generated imperfectly and irregularly. This type of imperfect regeneration is better termed as overgrowth.     

MSCs-exosomes in regeneration medicine: Current evidence and future perspectives

Exosomes, especially from mesenchymal stem cells, have attracted extensive attention in regeneration medicine. Mesenchymal stem cells derived exosomes (MSCs-exosomes) have shown anti-inflammatory, anti-oxidant, anti-apoptosis and tissue regeneration effects in a variety of tissue injury repair models. MSCs-exosomes hold many excellent properties such as low immunogenicity, biocompatibility, and targeting capability. With the in-depth study on the generation and function of exosomes, MSCs-exosomes are considered to be the bright stars in the field of regenerative medicine. However, there are still many obstacles to overcome in terms of exosomes isolation, clinical trials and safety evaluation. In this article, what we should focus on about MSCs-exosomes in regeneration medicine will be discussed.     

Mesenchymal stem cells-derived extracellular vesicles as ‘natural’ drug delivery system for tissue regeneration

Mesenchymal stem cells (MSCs) have abilities to mediate tissue protection through mechanisms of anti-apoptosis, anti-oxidative stress and anti-fibrosis as well as tissue regeneration through mechanisms of cell proliferation, differentiation and angiogenesis. These effects by MSCs are mediated by a variety of factors, including growth factors, cytokines and extracellular vesicles (EVs). Among these factors, EVs, containing proteins, mRNA and microRNAs (miRNA), may carry their contents into distant tissues with high stability. Therefore, the treatment with MSC-derived EVs may be promising as ‘natural’ drug delivery systems (DDS). Especially, the treatment of MSC-derived EVs with the manipulation of specific miRNAs expression has been reported to be beneficial under a variety of diseases and tissue injuries. The overexpression of specific miRNAs in the EVs might be through pre-loading method using the gene editing system by plasmid vector or post-loading method to load miRNA mimics into EVs by electroporation or calcium chloride-mediated transfection. Despite current several challenges for clinical use, it should open the next era of regenerative medicine for a variety of diseases. In this article, we highlight the therapeutic potential of MSC-derived EVs as ‘natural’ DDS and current challenges.     

Mesenchymal stem cells derived secretome as an innovative cell-free therapeutic approach

The paracrine and immunomodulatory cytokines secreted by mesenchymal stem cells (MSCs), generally referred to as the MSCs derived secretome, has substantial potential for the treatment of many chronic and degenerative diseases. MSCs secretome contains both common and disease specific cytokines and modulators that can be beneficial against a wide range of chronic diseases. Herein, we discuss the MSCs secretome composition profile and its translational applicability and the challenges surrounding its use in clinical settings.     

Optimization of culture conditions for an efficient xeno‐feeder free limbal cell culture system towards ocular surface regeneration

Ex vivo expansion of limbal stem cells from a small biopsy and its subsequent transplantation is the golden choice of treatment for limbal stem cell deficiency. Use of murine 3T3 feeder layer is a prerequisite for this ex vivo expansion. There is an ever‐increasing demand for feeder free cultures to avoid xenotoxicity and transmission of xeno‐diseases to human system. This study was aimed to establish an efficient xeno‐feeder free limbal culture system towards ocular surface regeneration. To study the effect of initial dispase treatment and culture system used, migratory distance of cells from explants was analyzed from phase contrast images using “interactive measurements” of Qwin software (Leica). Expression of p63 in different culture systems was studied by immunofluorescent staining, followed by quantitative confocal microscopy (Carl Zeiss). Results showed dispase treatment was not necessary for establishing limbal explant culture. A combination of Iscove's modified Dulbecco's medium and Panserin 801 resulted in formation of autofeeder layer with maintenance of progenitor characteristics, thus mimicking natural tissue architecture. Further analysis of this culture system showed that cells could be cultured till confluency. Immunofluorescent staining of ABCG2 revealed presence of stem cell marker in the confluent cell layer. Scanning Electron Micrographs demonstrated homogenous population of tightly packed cells in this culture system. Replacement of bovine serum with autologous serum did not affect morphology or growth of cells in this culture system. This study will be a major step in the development of xeno‐feeder free epithelial equivalents towards ocular surface reconstruction. Microsc. Res. Tech. 73:1045–1052, 2010. © 2010 Wiley‐Liss, Inc.     

A multiparametric assay for quantitative nerve regeneration evaluation

We introduce an assay for the semi-automated quantification of nerve regeneration by image analysis. Digital images of histological sections of regenerated nerves are recorded using an automated inverted microscope and merged into high-resolution mosaic images representing the entire nerve. These are analysed by a dedicated image-processing package that computes nerve-specific features (e.g. nerve area, fibre count, myelinated area) and fibre-specific features (area, perimeter, myelin sheet thickness). The assay's performance and correlation of the automatically computed data with visually obtained data are determined on a set of 140 semithin sections from the distal part of a rat tibial nerve from four different experimental treatment groups (control, sham, sutured, cut) taken at seven different time points after surgery. Results show a high correlation between the manually and automatically derived data, and a high discriminative power towards treatment. Extra value is added by the large feature set. In conclusion, the assay is fast and offers data that currently can be obtained only by a combination of laborious and time-consuming tests.     

变胞机构与机构再生运动链综合研究

变胞机构是机构在运动的过程中通过改变构件或运动副的数量或类型从而完成不同的功能,而机构再生运动链方法是根据初始机构通过综合理论得到所有可能的运动链的一种机构创新方法,由于这两种方法都要利用拓扑结构来表达,因此笔者创造性的将两种方法利用其内在的拓扑关系结合起来,从而提出了基于拓扑的变胞机构再生运动链创新方法,该方法为利用再生运动链对变胞机构的创新提供一定参考依据。     

基于机构创新设计的机构再生设计的探讨

介绍了机构再生设计法,该方法由传统的选型设计转向构型创新设计,在机构设计过程中缩短了设计周期,提高了工作效率.机构再生设计法着重研究现有机构简图一般化运动链,根据设计要求给原始机构一般化运动链各个杆件赋予不同的功能目的,从而再生出与原始机构不同构型的运动链.     

磷酸脂抗燃液压油及其再生净化设备的设计

分析了抗燃液压的主要特点和与机械油的区别,揭示了在工业上被广泛应用的趋势,介绍了抗燃液压油再生净化设备的工作原理和设计要点,难点,提出了主要技术参数。     

Comparative characterization of human fetal neural stem cells and induced neural stem cells from peripheral blood mononuclear cells

Human-induced neural stem cells (iNSCs) transplantation is a potential treatment of neurodegenerationdiseases. However, whether the reprogrammed cells have the same characterizations as human fetal neural stem cellsneeds further exploration. Here we isolated human fetal neural stem cells from aborted 12-week fetal brains andcompared with iNSCs reprogrammed from human peripheral blood mononuclear cells in gene expression, proliferationability, differentiation capacity, and the responses to tumor necrosis factor-α. We found that iNSCs and NSCs bothexpressed neural stem cell markers Nestin, SOX1, and SOX2. However, only iNSCs can be patterned into dopaminergicneurons and motor neurons. Furthermore, both iNSCs and NSCs can differentiate into oligodendrocyte progenitorcells. In addition, a low dose of tumor necrosis factor-α did not inhibit the proliferation and differentiation of iNSCsand NSCs. In conclusion, iNSCs have properties similar to, and even better than, fetal neural stem cells and may besuitable for disease modeling and transplantation.     

运行参数对内热型板式除湿溶液再生装置的性能影响试验研究

为了研究不同工况下内热型板式再生器的再生性能,搭建了再生试验系统,分别研究了空气、溶液以及热水入口参数对再生系统热质传递特性的影响,并运用SPSS软件对各参数进行敏感性分析.结果显示,空气侧入口流速对再生器的性能起到至关重要的作用,随着空气流速增加,再生量从0.82 g/s升至2.04 g/s,但再生效率从90.15％...     

DCS及PLC系统在阿钢中轧加热炉中的应用

主要介绍了DCS及PLC系统在阿城钢铁公司中型轧钢厂蓄热式加热炉中的应用情况,简述了自动控制系统的硬件构成和特点,对蓄热式加热炉的换向过程、炉膛压力和炉膛温度等自动控制过程进行了说明。经过一年多的实际运行,证明控制系统稳定可靠,为蓄热式加热炉稳定运行提供了保障。     

Autotomy as a prelude to regeneration in echinoderms.

'Autotomy' refers to the adaptive detachment of animal body parts where this serves a defensive function, is achieved by an intrinsic mechanism, and is nervously mediated. With regard to each echinoderm class, this article itemises those structures that are autotomous, evaluates the extent to which autotomy precedes regeneration in natural populations, reviews current knowledge of the morphology of autotomy planes and mechanisms that effect fracture at autotomy, and comments on autotomy-related issues arising from studies of the cellular events of regeneration. Each autotomy plane can be regarded as an assemblage of breakage zones traversing the individual anatomical components of the autotomous structure. In any one autotomy plane some breakage zones are permanent sites of weakness that are fractured by external forces and some are potential sites of weakness that undergo a loss of tensile strength only at the time of autotomy. The latter occur predominantly in mutable collagenous structures, although there are a few examples of muscles that undergo an endogenous rupturing process. Available evidence indicates that autotomy is by far the commonest proximate cause of structural loss in echinoderms. Most echinoderm regeneration is therefore necessitated by autotomy and proceeds from the retained side of a fractured autotomy plane. Due to a lack of relevant research there is as yet little evidence for or against the presence of specific regeneration-promoting adaptations at autotomy planes, although it is argued that an autotomy plane designed primarily to effect rapid detachment would by itself increase regenerative efficiency.     

Tracking oligodendrocytes during development and regeneration

Over the past decade, advances in strategies to tag cells have opened new avenues for examining the development of myelin-forming glial cells and for monitoring transplanted cells in animal models of myelin insufficiency. The strategies for labelling glial cells have encompassed a range of genetic modifications as well as methods for directly attaching labels to cells. Genetically modified oligodendrocytes have been engineered to express enzymatic (e.g., beta-galactosidase, alkaline phosphatase), naturally fluorescent (e.g., green fluorescent protein), and antibiotic resistance (e.g., neomycin, zeomycin) reporters. Genes have been introduced in vivo and in vitro with viral or plasmid vectors to somatically label glial cells. To generate germ-line transmission of tagged oligodendrocytes, transgenic mice have been created both by direct injection into mouse fertilized eggs and by "knock-in" of reporters targetted to myelin gene loci in embryonic stem cells. Each experimental approach has advantages and limitations that need to be considered for individual applications. The availability of tagged glial cells has expanded our basic understanding of how oligodendrocytes are specified from stem cells and should continue to fill in the gaps in our understanding of how oligodendrocytes differentiate, myelinate, and maintain their myelin sheaths. Moreover, the ability to select oligodendrocytes by virtue of their acquired antibiotic resistance has provided an important new tool for isolating and purifying oligodendrocytes. Tagged glial cells have also been invaluable in evaluating cell transplant therapies in the nervous system. The tracking technologies that have driven these advances in glial cell biology are continuing to evolve and present new opportunities for examining oligodendrocytes in living systems. Microsc. Res. Tech. 52:766-777, 2001. Published 2001 Wiley-Liss, Inc.     

Anterior regeneration after fission in the holothurian Cladolabes schmeltzii (Dendrochirotida: Holothuroidea)

The regeneration of the anterior portion of the body after fission was studied in the holothurian Cladolabes schmeltzii using electron microscopy methods. Following fission, the posterior portion of the digestive tube, cloaca, and respiratory trees remain in the posterior fragment of the body. The regeneration comprises five stages. In the first stage, connective‐tissue thickening (an anlage of the aquapharyngeal bulb) occurs on the anterior end between the torn‐off ends of the ambulacra. Most of the lost anterior organs developed in the second and third stages. The structures of water‐vascular system and nerve ring form through dedifferentiation, proliferation, and migration of cells of the radial water‐vascular canals and the radial nerve cords, correspondently. The lost digestive system portion is restored through the formation and merging of two anlagen. The digestive epithelium of the esophagus and pharynx develops from lining cells of microcavities near the central portion of the connective‐tissue thickening, which probably migrate from the epidermis. The second gut anlage develops through transformation of the anterior gut remnant portion. The enterocytes partly dedifferentiate, but the epithelium retains integrity. The gut anlage grows down the mesentery and joins the regenerating aquapharyngeal bulb. In the fourth and fifth stages, all lost organs are formed and have nearly normal structure. The regeneration was concluded to occur through morphallactic rearrangements of the remaining parts of organs. Epithelial morphogenesis is the key development mechanism of the digestive, water‐vascular, and nervous systems.     

Evaluation of power regeneration in primary suspension for a railway vehicle

Frontiers of Mechanical Engineering - To improve the fuel economy of rail vehicles, this study presents the feasibility of using power regenerating dampers (PRDs) in the primary suspension systems...