The Micronucleus Technique In Epidemiological Studies

Summary: The micronucleus assay measure chromosome damage at the level of single cells. Micronuclei originate from chromosome fragments or whole chromosomes that are not included in the main daughter nuclei during nuclear division. The method is very easily applied to human lymphocytes and in various cell types, and therefore lends itself to human biomonitoring studies. This assay is now in widespread use to assess effect of the impact of environmental, genetic and lifestyle factors  on genomic stability.  The underlying principles of this assay  including criteria for scoring micronuclei are described. Moreover this paper describes some of the results published in the literature where frequency of micronucleus was used as a biomarker of cancer risk and other degenerative diseases. The influence of metabolic genotypes on different biological markers of genotoxic risk in environmental or occupational exposure are reviewed.

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Protein Import Into Mitochondria

Summary: Mitochondria import majority of their proteins from the cytosol. The recognition and translocation across the mitochondrial membranes are supported by dynamic protein complexes termed the translocase of the outer membrane (the TOM complex) and translocase of inner membrane (the TIM complex).The translocases consist of  receptor proteins and proteins involved in protein translocation. The dynamic nature of  both membrane translocases  permits sorting  of preproteins at distinct stages of the import pathway. Essential factors in protein import are also cytosol, intermembrane space and matrix proteins. The link between mitochondrial import defects and some of the   neurological diseases is crucial to  explanation  of their molecular bases.

Key words: Protein import, TOM complex, TIM complex, mitochondria
 

Molecular Aspects of Somatic Cloning in Animals

Summary: Advances in the somatic cloning of animals were possible thanks to research on the nuclear-cytoplasmic interactions between enucleated recipient-oocyte and donor exogenous cell nucleus. One of the factors that has a direct influence on these interactions is the level of MPF activity in the oocyte cytoplasm. High level of MPF activity affects the microtubular cytoskeleton, nuclear envelope as well as the spatial form of chromatin enabling coordinated replication of DNA in the reconstructed oocyte. This leads to the activation of molecular mechanisms responsible for the reprogramming of the genome of thedonor somatic cell in the recipient-oocyte's cytoplasm.

Key words: oocyte,  MPF,  cell cycle,  reprogramming

The Role of Macrophages in Mammals Reproductive Tract: From Paul Ehrlich to Present Immunology of Reproduction

Summary: In mammals birth marks introduction of the newborn to external environment where it is exposed to various disease causing agents (bacteria, viruses and/or fungi). Protection against pathogens is afforded by the immune system in which macrophages participate significantly. Macrophages are classified as professional antigen presenting cells (APC) but are also involved in various equally important functions such as phagocytosis, thereby render protection against infectious agents. These vital cells are also present in the reproductive tract of both male and female mammals where they engage in reproductive processes both at cellular and molecular level e.g., signal transduction. The magnitude of macrophage population and function is strictly regulated by estrogens and progesterone through secretory control of monocyte-macrophage colony stimulating factor (M-CSF, also known as CSF-1) which apparently is a major macrophage chemoattractant. In males macrophages participate in the regulation of steroidogenesis. Ovaries, oviduct, uterus, cervix and the vagina are sites where macrophages target the female reproductive tract. They actively participate in oogenesis and follicle development as well as in formation and function of the corpus luteum. Macrophages are also implicated in stimulating angiogenesis in ovary tumours. The most significant function attributed to oviduct macrophages is their effect on oocyst and embryo transport achieved through cytokine and prostaglandin activity on  the oviduct epithelium and smooth muscle layer. Cytokines secreted by uterine macrophages contribute to the preimplantation development and subsequent implantation of the embryo. Cervical and vaginal mucosa macrophages form a cellular defence line mainly evidenced by phagocytosis and antigen presentation to T cells. Moreover, particular cytokines produced by cervical macrophages allow relaxation of the cervical muscles enabling normal parturition. This review discusses the current knowledge on the role of macrophages and influence of particular cytokines on reproductive processes in mammals.

Key words: reproductive tract, macrophages, cytokines

Fractal Analysis of Cells Shape

Summary: Shape of the nervous tissue cells is often very complicated and to describe it we have to apply advanced methods of mathematical analysis. One of these methods derives from fractal geometry. This paper presents selected basic methods of calculation of the cell fractal dimension and examples of their application. Fractal dimension can be measured by pixel dilation, box counting, calliper and mass-radius methods. The methods can be used to measure the space-filling properties of various cell types, blood vessels, tumours etc. Additional parameters of the cell such as its solidity, convex hull area and form factor describe different shape features and are of important values complementary to fractal dimension. Simultaneous application of the parameters together with fractal dimension present characteristics of the cell morphology more complete.

Key words: fractal analysis, morphology, glia, neurones
 

Influence of Osmotic Pressure on Physiological Condition of Bacterial Cells

Summary: Microorganisms are all the time exposed to highly stressful circumstances including osmotic stress, temperature, and pH changes. To survive under the unfavourable conditions microorganisms posses specific adaptation mechanisms. Under osmotic stress conditions, meant as a sudden decrease or increase of osmotic pressure, particularly important is to maintain turgor pressure at appropriate level. To keep intracellular osmolarity and turgor pressure balanced there is limited group of organic osmolytes - compatible solutes. Many microorganisms accumulate compatible solutes during periods of decreased water activity. The controlled amassing of these organic osmolytes allow the cells to control turgor pressure. Besides, compatible solutes have a positive influence on membrane stabilization and proteins structure. The osmolarity of the environment regulates intracellular concentration of compatible solutes. This involves changes in transport systems activities (uptake from environment) and/or synthesis.

Key words: Osmoregulation, stress protectants, glycine betaine, proline, Bacillus subtilis, Escherichia coli
 

E-NTPDases - Enzymes Involved in Signalling Processes in the Central Nervous System

Summary: The E-NTPDase (ecto-nucleoside triphosphate diphosphohydrolase family, E-phoshohydrolases ATP) belongs to the family of enzymes previously called ecto-ATPases and ecto-apyrases, which hydrolyze a variety of ecto-tri- and ecto-diphosphonucleosides in presence of divalent cations. There is strong evidence that E-phosphohydrolases ATP are involved  in signaling processes via ATP and purinoceptors. The function of those enzymes is not restricted to releasing agonist from purinoceptors. They also regulate the velocity and intensity of cell response to purinergic signal by maintaining the balance between concentration of ATP and concentration of adenosine. Lack of [ATP]:[adenosine] balance may lead to different diseases. The reason for existence of E-NTPDase 2 in synapse remains unclear. In our opinion E-NTPDase 2 participates in lowering  the high ATP concentrations in synaptic cleft and degradation of ATP to another signaling molecule - ADP.

Keywords: E-NTPDases, ecto-enzymes, ecto-ATPases, ecto-apyrases, ATP, central nervous system.
 

Experimental and Clinical Application of Interleukin 12 (IL-12) - Gene-Based Therapy in Tumour Treatment

Summary: The strategy concerning the modification of cells with genes encoding cytokines is an intensively developing branch of tumour gene therapy.  Many experiments show that inserting IL-12 gene into cells is one of the most effective therapeutic approaches. IL-12, when produced in the tumour microenvironment efficiently stimulates antitumour immunity, preventing severe toxicities caused by IL-12 given systemically. The majority of research papers concern the therapy with ex vivo IL-12 gene modificated tumour cells, used as antitumour vaccines. High therapeutic efficiency of fibroblasts modificated to secrete IL-12 has also been shown. Further, insertion of IL-12 gene into dendritic cells made these cells highly efficient and improved their function as antitumour vaccine. The development of genetic engineering methods has allowed in vivo transduction of cells with IL-12 gene, by adenoviral gene transfer as well as Vaccinia Virus or Herpes Simplex Virus vectors. Nonviral IL-12 gene transfer methods used direct injection of naked DNA into skeletal muscles, skin or tumour tissue. The effectiveness of gene transfer has been improved by electroporation or the gene gun method. Also the trial with IL-12 gene given per os has already been undertaken. The efficacy of tumour gene therapy with IL-12 gene has been enhanced by simultaneous administration of cytokines: IL-2, -15, -18, GM-CSF, TNF-?, chemokines: IP-10 and MIG, insertion of genes for costimulatory molecules B7.1 and 4-1BB and also by addition of adoptive therapy approaches. The experiments in animal models have documented the therapeutic effectiveness of modification of cells with IL-12 gene. As a result of that, the first clinical trials have been undertaken.

Key words: IL-12, tumour gene therapy

The Role of Rel/NFkB/IkB Proteins in the Pathogenesis of Cancer

Summary: The family of transcription factors Rel/NFkB/IkB plays a pivotal role in the regulation of a wide spectrum of immune and inflammatory responses as well as normal and malignant cellular growth control. In this review, we present current knowledge of the structure, mechanisms of action, biological function and the role of Rel/NFkB/IkB proteins in the pathogenesis of retroviral-induced cancers and other human cancers, mainly leukemias and lymphomas. Subsequently, different methods of counteracting the disturbances in their function associated with malignant transformation are discussed.

Key words: Rel/NFkB, transcription factors, IkB proteins, malignant transformation.
 

Embryonic Development of Coronary Vessels and Some Mechanisms of its Regulation

Summary: This paper presents current views on fundamental stages of coronary vessel development in experimental animals. The tissue for developing vessels comes from the proepicardial organ which is a transiently occurring structure and forms on the surface of the septum transversum (in mammals) or on sinus venosus (in birds). Proepicardium is a forerunner of the epicardium. The first vessel primordia are formed de novo subepicardially as isolated blood islands and subsequently vessel buds in the areas of sinus venosus, the coronary and the interventricular sulcuses, and the aorticopulmonary groove. Then the vessel primordia lumenize and finally coalesce in an unknown way into a continous vessel system. Proximal parts of the coronary arteries originate from the peritruncal plexus of capillaries which penetrate into the aortic sinuses and form patent connections with the aortic lumen. Concomitantly patent connections are formed between the venules and the right atrium and the coronary sinus. After the blood flow through the patent coronary system have been established mesenchymal cells of the primitive tunica media started to differentiate in smooth muscle cells by acquisition of contractile phenotype antigens. This process of differentiation lasts till the end of the prenatal life. The expression of growth factors like VEGF and angiopoietins (-1, -2) is seen in embryonic hearts in areas of vessel formation. Endothelial cells of the coronary vessels derive from angioblasts of the fetal liver area from where they migrate to the proepicardium and then to subepicardium and finally myocardium. Precursors of smooth muscle cells of the coronary vessels and the adventitial fibroblasts derive from the epicardiac  mesothelium through the epithelial-mesenchymal transformation. Then they migrate to the respective myocardial areas and differentiate into smooth muscle cells and firoblasts, respectively.

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