Literature Suvey

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Multiline age Potential of Adult Human Mesenchymal Stem Cells: Human mesenchymal stem cells(1) are thought to be multipotent cells, which are present in adult marrow, that can replicate as undifferentiated cells and that have the potential to differentiate to lineages of mesenchymal tissues, including bone, cartilage, fat, tendon, muscle, and marrow stroma. These cells displayed a stable phenotype and remained as a monolayer in vitro. These adult stem cells could be induced to differentiate exclusively into the adipocytic, chondrocytic, or osteocytic lineages. Individual stem cells were identified that, when expanded to colonies, retained their multiline age potential. Isolation of amniotic stem cell lines with potential for therapy: Stem cells capable of differentiating to multiple lineages may be valuable for therapy. Undifferentiated (AFS) (2) cells expand extensively without feeders, double in 36 h and are not tumorigenic. AFS cells are broadly multipotent. Clonal human lines verified by retroviral marking were induced to differentiate into cell types representing each embryonic

Transcript of Literature Suvey

Multiline age Potential of Adult Human Mesenchymal Stem Cells:Human mesenchymal stem cells(1) are thought to be multipotent cells, which are present in adult marrow, that can replicate as undifferentiated cells and that have the potential to differentiate to lineages of mesenchymal tissues, including bone, cartilage, fat, tendon, muscle, and marrow stroma. These cells displayed a stable phenotype and remained as a monolayer in vitro. These adult stem cells could be induced to differentiate exclusively into the adipocytic, chondrocytic, or osteocytic lineages. Individual stem cells were identified that, when expanded to colonies, retained their multiline age potential.Isolation of amniotic stem cell lines with potential for therapy:Stem cells capable of differentiating to multiple lineages may be valuable for therapy. Undifferentiated (AFS)(2) cells expand extensively without feeders, double in 36 h and are not tumorigenic. AFS cells are broadly multipotent. Clonal human lines verified by retroviral marking were induced to differentiate into cell types representing each embryonic germ layer, including cells of adipogenic, osteogenic, myogenic, endothelial, neuronal and hepatic lineages. Stem Cell Therapy:Amniocentesis(3) done when a woman is between 16 and 20 weeks pregnant. Mainly to detect the increased risk for genetic and chromosomal problems, in part because the test is invasive and carries a small risk of miscarriage. Usually done to assess the maturity of baby's lungs, to diagnose or rule out an intrauterine infection, to check blood sensitization, such as Rh sensitization.Isolation of human multipotent mesenchymal stem cells from secondtrimester amniotic fluid using a novel twostage culture protocol:The aim of this study was to isolate(4) mesenchymal stem cells (MSCs) from amniotic fluid obtained by secondtrimester amniocentesis. A novel twostage culture protocol for culturing MSCs was developed. Flow cytometry, RTPCR and immunocytochemistry were used to analyse the phenotypic characteristics of the cultured MSCs.Amniotic fluid as a novel source of mesenchymal stem cells for therapeutic transplantation:Human mesenchymal stem cells (MSCs) are multipotent stem cells, able to differentiate into multiple mesenchymal lineages. Previously human fetal lungderived MSCs enhance the engraftment of human umbilical cord blood (UCB)derived CD34+ hematopoietic cells in nonobese diabeticsevere combined immunodeficiency mice. Second-trimester amniotic fluid(5) is an abundant source of fetal MSCs that exhibit a phenotype and multilineage differentiation potential similar to that of postnatal bone marrow (BM)derived MSCs. Thus, amniotic fluid is an attractive source of MSCs for transplantation in conjunction with UCB-derived hematopoietic stem cells.Amniotic fluid cells and human stem cell research: a new connection:Human progenitor cells and stem cells can be widely used to replace dysfunctional cells within a tissue. It is speculated that such cells may prove to have the potential to treat or cure a myriad of diseases, including Parkinson's and Alzheimer's diseases, heart disease, diabetes, stroke, spinal cord injuries, and burns. The area of research is to identify potential new sources for the isolation of progenitor cells(6) or stem cells, without raising the ethical issues involved in embryonic stem cell research.Use of Mesenchymal Stem Cells for Therapy of Cardiac Disease:Among the cell types under investigation, adult mesenchymal stem cells are widely studied, and in early stage, clinical studies show promise for repair and regeneration of cardiac(7) tissues. The ability of mesenchymal stem cells to differentiate into mesoderm- and non-mesoderm-derived tissues, their immune-modulatory effects, their availability, and their key role in maintaining and replenishing endogenous stem cell niches have rendered them one of the most heavily investigated and clinically tested type of stem cell, when delivered as either autologous or allogeneic forms in a range of cardiovascular(8) diseases, but also importantly define parameters of clinical efficacy that justify further investigation in larger clinical trials.Identification, purification, and biological characterization of hematopoietic stem cell factor from buffalo rat liver-conditioned medium:We Identified a novel growth factor, stem cell factor (SCF), for primitive hematopoietic(9) progenitors based on its activity on bone marrow cells derived from mice treated with 5-fluorouracil. The protein was isolated from the medium conditioned by Buffalo rat liver cells. It is heavily glycosylated, with both N-linked and O-linked carbohydrate. Amino acid sequence following removal of N-terminal pyroglutamate is presented. Separation of pluripotent haematopoietic stem cells from spleen colony-forming cells:Several cell-separation techniques based on cell-surface characteristics have been used in attempts to identify the pluripotent haematopoietic stem cells (PHSC), and have allowed the long-term engraftment of lethally irradiated mice with an enriched fraction of fewer than 200 marrow cells(10). But these techniques enrich not only for PHSC but also for haematopoietic progenitors, especially day-12 spleen colony-forming units (CFU-S)Separation of plasma from whole human blood in a continuous cross-flow in a moulded microfluidic device:The device is made of a single mould of a silicone elastomer poly(dimethylsiloxane) (PDMS) sealed with a cover glass and is essentially disposable(11). When loaded with blood diluted to 20% haematocrit and driven with pulsatile pressure to prevent clogging of the channels with blood cells, the device can operate for at least 1 h, extracting 8% of blood volume as plasma at an average rate of 0.65 L/min. The flow in the device causes very little haemolysis; the extracted plasma meets the standards for common assays and is delivered to the device outlet 30 s after injection of blood to the inlet. Integration of the cross-flow micro channel array with on-chip assay elements would create a microanalysis system for point-of-care diagnostics, reducing costs, turn-around times, and volumes of blood sample and reagents required for the assays.Continuous flow separations in microfluidic devices:In recent years, however, many research groups have demonstrated continuous flow separation methods in microfluidic devices. Such separation methods are characterised by continuous injection, real-time monitoring, as well as continuous collection(12), which makes them ideal for combination with upstream and downstream applications. Importantly, in continuous flow separation the sample components are deflected from the main direction of flow, either by means of a force field (electric, magnetic, acoustic, optical etc.), or by intelligent positioning of obstacles in combination with laminar flow profiles. Microfluidic chip for blood cell separation and collection based on cross flow filtration:Cell separation(13) and sorting are essential steps in cell biology research and in many diagnostic and therapeutic methods. Recently, there has been interest in methods which avoid the use of biochemical labels; numerous intrinsic biomarkers have been explored to identify cells including size, electrical polarizability, and hydrodynamic properties. This review highlights microfluidic techniques used for label-free discrimination and fractionation of cell populations. Microfluidic systems(14) have been adopted to precisely handle single cells and interface with other tools for biochemical analysis. Computational micro fluid dynamics using COMSOL Multiphysics for sample delivery in sensing domain(15):Engineering of fluid flow with within various structure for different application is a scientific quest and Microfluidic devices present a powerful platform for working with living cells and other medical application. The length and volume scales of these devices in miniaturize system make it possible to perform detailed analyses with several advantages. However, the COMSOM Multiphysics approach was not addressed a sufficiently. COMSOL Multi physics based model for fluid flow within a Polydimethylsiloxane (PDMS) polymer. The trend predicted by the new model agrees with experimental extrusion results observed. The proposed method allows further extension to study of the structural property of fluid in the COMSOL environment for possible interaction with sensor transducer.A combined micro magnetic-microfluidic device for rapid capture and culture of rare circulating tumour cells(16)a combined micro fluidic-micro magnetic cell separation device that has been developed to isolate, detect and culture circulating tumour cells (CTCs) from whole blood, and demonstrate its utility using blood from mammary cancer-bearing mice. The device was fabricated from Polydimethylsiloxane and contains a microfluidic architecture with a main channel and redundant double collection channel lined by two rows of dead-end side chambers for tumour cell collection. Immunophenotype of Human AdiposeDerived Cells: Temporal Changes in StromalAssociated and Stem CellAssociated Markers(17)Tissues were washed three to four times with phosphate-buffered saline (PBS) and suspended in an equal volume of PBS supplemented with 1% bovine serum and 0.1% collagenase type pre-warmed to 37C. The tissue was placed in a shaking water bath at 37C with continuous agitation for 60 minutes and centrifuged for 5 minutes at 300 to 500g at room temperature. The supernatant, containing mature adipocytes, was aspirated.

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