Rregenerative and Immunomodulatory Properties of Adipose-Derived Mesenchymal Stem Cells
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Summary:
The brain of adult animals, including humans, sustained the ability to
create new glial cells and neurons. This process is called postnatal
neurogenesis. It is possible owing to the presence of neuronal stem
cells in the neurogenic zones. The subependymal layer, a part of
periventricular zone, demonstrates the highest intensity of
neurogenesis. Ependymal cells, forming the external lining of the
lateral ventricles, can also effectively differentiate into cells of
the nervous system. Ependymal cells (ependymocytes) originate from
radial glia and are created during embrional and early postnatal
development. Ependymocytes of adult mammalian brain form migrating
cells differentiating into astrocytes and neurones. Ependymal cells
express neuroprogenitor markers like Sox2 or nestin and adult stem
cells marker – CD133. Subependyma is layered below the uniform
ependyma lining. It is formed of a few diverse types of cells. There
are numerous data indicating that subependymal, GFAP-positive
astrocytes proliferate intensively and they have the characteristics of
neural stem cells. The subependymal zone is a niche for neural stem
cells, neuronal and glial precursor (progenitor) cells, neuroblasts and
glioblasts that are immature neurons and glia, respectively. Ependymal
and subependymal zone emerges to be a rich source of neural stem cells.
Neural stem cells (NSCs) are primary cells with the ability of
self-renewal or differentiation into one of three types of nervous
system cells: neurons, oligodendrocytes or astrocytes. NSCs isolated
from neurogenic zones of adult mammalian brain can be cultured in vitro in two systems: as monolayer system or as culture of neurospheres. Neurospheres cultured in vitro
are spherical or elipsoidal structures formed of hundreds of cells
surrounded by an envelope rich in extracellular matrix components. The
cells forming neurosphere differ in their size, presence of cytosolic
granules, number of mitochondria, the phase of cell cycle. Neurospheres
appear as complex biological structures in which events such as
phagocytosis, mitosis, apoptosis and even necrosis occur at the same
time. The amount of NSCs in neurospheres is estimated as about 0.16%.
In physiological conditions proliferation and differentiation of neural
stem cells are precisely regulated through different interactions and
signalization systems within the niche. The attempt to recognize these
complex interactions and to fully characterize all the factors and
signaling systems is still a challenge for the researchers. In this
article we describe only these molecules and pathways of signalization
that are quite well characterized. Our understanding of the mechanisms
regulating proliferation and differentiation of NSCs will allow to
precisely control these processes in in vitro cultures. These findings
will help to applicate NSCs in the therapy of neurodegenerative
diseases like Alzheimer or Parkinson disease, brain injury and stroke.
Key
words:
ependyma, subependyma, neural stem cells, neurospheres, differentiation control
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Role of Regulatory T Cells in Pregnancy
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Chemerin – a New Regulator of Metabolic and Immune Processes
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Th17 Lymphocytes a New Ally in the Fight Against Ovarian Cancer?
Key words: Th17 lymphocytes, interleukin 17, ovarian cancer, anti-tumor response
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Interleukin 15 – What Do We Know? THE Structure, Receptors And Inhibitors
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Summary: Molecular
analysis are mostly carried out in heterogeneous biological material,
and results obtained in this way illustrate the status quo that existed
in different cell types, also in cells that are not the object of our
interest. This article aims to familiarize the reader with a technique
for precisely obtaining material for molecular studies, which is laser
microdissection. This method allows the separation of even a single
cell from a heterogeneous material almost unchanged, both
morphologically and biochemically. This publication is a summary of
knowledge about the types of laser microdissection, the general
principles of their operation and examples of their applications.
Keywords: laser microdissection, molecular biology
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Dental Pulp Stem Cells. Possibilities of Application in Contemporary Dentistry And Future Directions – Review
Summary: Introduction: multipotential stem cells are already applied for guided tissue regeneration, therefore the challenge of contemporary dentistry is to apply dental pulp stem cells for guided dentin regeneration. The in vitro and in vivo studies as well as a molecular analysis showed such a possibility. So far, bone marrow stem cells (BMSC) have been successfully utilized for treatment of the autoimmuno-logical syndromes and cancers. BMSC have been well recognized, however the way of their isolation may be hazardous for a patient. Thus researchers are taking efforts to recruit stem cells from the better accessible sources. Molecular studies discovered the presence of multipotential stem cells in dental pulp (DPSC). When culture under the scrutinized conditions the dental pulp stem cells differentiate into odontoblasts and subsequently in vivo produce a dentin and dentin - pulp complex. It is expected that tissue engineering with DPSC will allow for replacement of traditional dental materials to in vitro generated dentin. Aim of the study: a review of the newest data concerning specificity of DPSC, as well as their possibilities of application in dentistry has been made. Moreover comparison of DPSC and BMSC has been studied. |
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Innovative Methods of Archiving, Presentation and Providing Access to Histological Sections at the Example of the Center of Morphologic Images Archivization and Digital Database of Microscopic Pictures Operating in Poznan University of Medical Sciences
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Induced Damages of DNA by Mutagens and Mechanisms of Their Formation
Summary: The genomes of all living organisms are extremely stable. DNA in the cell is replicated during cell division and passes all the genetic information to the next generation. It is essential for all living organisms to ensure proper functioning and propagation of their genetic information. Due to constant exposure of the genome to various endogenous and exogenous agents, however, the DNA becomes damaged leading to a large variety of DNA lesions. The endogenously generated damage of DNA is known as spontaneous DNA damage, which is produced by reactive metabolites and defects in normal processes of DNA replication or recombination. The exogenous DNA-damaging agents include chemical mutagens, for example base analogs, alkylating agents and aromatic compounds, and physical mutagens: UV light, ionizing radiation and high temperature. The DNA lesions produced by these damaging agents could result in a base modification, such as alkylation and oxidation, base deletion, cyclobutane dimers, 6–4 photo-products, strand breaks, intra- and interstrand cross-links. Those damages of DNA have genotoxic or cytotoxic impact to the cell. Although most mutations are either neutral or harmful, some mutations have a positive effect on an organism. In this case, the mutation may enable the mutant organism to withstand particular environmental stresses better than wild-type organisms, or to reproduce more quickly. Mutagenesis is used to induce mutations at high frequency that include ionizing radiation and chemical mutagens for basic plant research and plant breeding. |
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Structure and Function Oviduct-Specific Glycoprotein 1
Summary: Oviduct specific glycoprotein 1 (OVGP1) also known as pOSP, MUC-9, sOP92, EAP, EGP and OGP, is produced by non-ciliated oviductal epithelium in many mammalian species. After its secretion to the oviductal fluid OVGP1 participates in the final gamete maturation, sperm capacitation, fertilization and supports early embryonic development. Secretion and expression of OVGP1 is regulated by steroid hormones and depends on the oestrus cycle. Molecular analysis of OVGP1 indicated that it is highly conserved at both amino acid and nucleotide levels. The main divergence has been observed in the carboxy terminal region containing deletions, insertions and tandem-repeat sequences containing O- and N- glycosylation sites. The carbohydrates protect OVGP1 protein and modulate its specificity and biological activity. Additionally, other post-translational modifications (phosphorylation, sialic acid residues, sulphation) contribute to the diversity of actions of OVGP1 among different species. |
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Structure and Regulation of Plant Vacuolar H+-ATPase
Summary: lant vacuolar H+-transporting ATPases (V-ATPases) are ATP-driven proton pumps, located mainly in the vacuolar membrane, that generate proton motive force used to energize secondary active transports operating at the tonoplast. V-ATPases are the oldest and most complicated proton pumps found in plant cells. Enzyme subunits are divided into two major domains, the catalytic peripheral V1 domain responsible for ATP hydrolysis and the membrane-integral V0 domain responsible for H+ translocation. V1 sector consists of eight subunits named A-H whereas V0 complex is composed of a, c, c”, d, and e subunits. In Arabidopsis thaliana, the 13 V-ATPase subunits are encoded by a total of 28 VHA genes suggesting the presence of individual subunit isoforms and different V-ATPase complexes specific to plant organs, tissues or physiological and developmental stages. The activity of plant V-ATPases is subjected to regulation at both the transcriptional and posttranslational levels. Potential mechanisms of biochemical regulation include reversible phosphorylation, redox regulation and modification induced by changes in the lipid composition of membrane. It has been postulated that under environmental stress the V-ATPase functions as a stress response enzyme, undergoing moderate changes in expression of subunits and modulation of enzyme activity. Since it was involved in ecophysiological adaptations at the molecular level, the V-ATPase was denominated an „eco-enzyme”. Numerous studies have confirmed an essential role of the V-ATPase in plant tolerance to environmental stresses including salinity, heavy metals and low temperature. |
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Alanine Aminotransferase in Higher Plants
Summary: Alanine:2-oxoglutarate aminotransferase (EC 2.6.1.2), also called alanine aminotransferase (AlaAT), catalyses transamination reaction between L-alanine and 2-oxoglutarate and the reverse reaction between L-glutamate and pyruvate. It is one of the most important enzymes involved in the synthesis and degradation of L-alanine. There are multiple isoenzymes of this enzyme (2 to 6) present in plants. Subcellular location of these isoenzymes appears to be directly associated with their metabolic role: (i) in C4 plants (Paniculum miliaceum) alanine aminotransferase participates in the transfer of C3 units (pyruvate) from mesophyl to bundle sheath cells, (ii) peroxysomal alanine aminotransferase exhibiting L-glutamate : glyoxylate aminotransferase activity is involved in regulation of photorespiration, (iii) alanine aminotransferase lacking L-glutamate : glyoxylate aminotransferase activity participates in hypersensitivity response to virus attack and (iv) regulates the alternative oxidase activity in miotchondria. Activation of alanine aminotransferase and simultaneous L-alanine acumulation was observed in plants subjected to hypoxia. On this base it was proposed, that this enzyme is involved in the response mechanisms that allow plants to survive under various adverse conditions such as periodic flooding of fields or lingering of snow cover. Research on transgenic plants also indicated its crutial role in nitrogen metabolism. Moreover peroxysomal alanin aminotransferase capable of using glyoxylate as amino group acceptor appeared to be involved in regulation of serine, citruline and glycine contents in leaves. |
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