It has been recently proposed that NG2 proteoglycan expressing cells may stand for a unique class of glia in adult CNS referred to as oligodendrocyte progenitor cells (OPCs). These NG2 positive cells can give rise to mature oligodendrocytes, however a large number of them persists in immature stage throughout a lifetime and responds to various types of injury. In order to investigate OPCs reactivity in vitro, a model of trimethyltin evoked neurodegeneration was used. The results demonstrate that NG2 expressing cells survive treatment with the neurotoxin in a concentration that injures most of neurons in the culture. Moreover, progenitors change their morphology when treated with trimethyltin, upregulate the NG2 proteoglycan expression and retain the ability to divide.
This review describes a new method of reticulocyte analysis based on flow cytometry, better than manual reticulocyte counting. Reticulocyte percentage, absolut number, indexes of maturity (RMI- Reticulocyte Maturity Index, IRF ? Immature Reticulocyte Fraction) and others qualitative parameters express the erythropoietic activity of kidneys and bone marrow. The new proposed parameters can improve the diagnosis of anemias and others haematological disorders like leukemia, myelodysplastic syndrom. They also provide exactly and early information about the status of bone marrow after ablative chemotherapy and transplantation. Automated reticulocyte counting can create new potentials for haematology diagnosis.
Nuclear factor kB (NF-kB) is common proinflammatory transcription factor involved in expression of c.a. 300 different genes. It is usually present in the cytosol as an inactive complex and upon activation translocates into the nucleus. The mechanisms of activation of NF-kB are complex and they involve several different signaling pathways and plethora of proteins. In this minireview we describe the main deciphered as well as suggested mechanisms regulating of NF-kB activity
Single human skin fibroblasts and the skin keratinocyte cell line HaCaT show contact guidance and elongate along narrow (1-2 Fm) scratches in glass substratum. During cell division these cells orientate their mitotic spindles along the long axis of the cell. Immunofluorescence staining of actin, tubulin, chromatin, and the nuclear NuMA protein complex demonstrated that cell elongation along scratches is accompanied by a corresponding rearrangement in the cytoskeleton. The results and literature suggest the following steps in the interplay between outside-in and inside-out signalling in the regulation of cell division orientation by extracellular factors. The interaction of cell surface with an anisotropy in the local environment causes changes in F-actin organization, cell elongation and alignment of stress fibres along the cell axis. This is accompanied by a corresponding reorientation of microtubules. Microtubules mediate between cell shape changes dependent upon cell interaction with substratum or other cells, the cortical actin and the position of centrosomes. Centrosomes determine the position and orientation of the mitotic spindle. The astral and central microtubules of the mitotic spindle control the localization of contraction-relaxation in the cell cortex and the position of the constriction ring and cell division plane.
During myotomal myogenesis in Hymenochirus boettgeri primary myoblasts differentiate into morphologically and functionally mature, mononucleate myotubes. Further muscle development in the studied species is due to fusion of mesenchymal cells with the latter, resulting in the presence of two classes of nuclei in the myotube: large of myotomal origin and small of mesenchymal origin. Densitometric measurements of DNA content revealed that the myotube nuclei at stages 35 reached values close to 4C DNA (3, 3C DNA), while at a later stage (42) the values were equal to 4C. Conversely, the secondary myoblast nuclei following the fusion with the myotube at stage 42 had 2C DNA ? a content comparable to that found in erythrocyte nuclei. PCNA (Proliferating Cell Nuclear Antigen) ? marker of S-phase of cell cycle, detected in the myotube nuclei (at stages 35, 42) appears during DNA replication.
Main part of eukaryotic genomes is build of unique sequences coding proteins and RNAs, but they contain as well numerous repeats interspersed with single-copy fragments. Existence of repetitive sequences were also demonstrated in in prokaryotic genomes. They are found in different species of Gram-negative and Gram-positive bacteria. Interspersed repetitive sequence elements called REP and ERIC sequences are present in different species of Enterobacteriaceae family, including Escherichia coli and Salmonella typhimurium. Their functions are not completely clear, probably they play important role in regulation of gene expression. Nevertheless, REP and ERIC elements are widely use in identification and genetic analysis of bacteria. For example, using rep-PCR technique it is possible to descriminate between closly related serovars of the same species, which enables to analyse phylogenetic and epidemiological relations among them.
Neuroendocrine activation belongs to the main characteristics of the stress response.This response is not uniform but depends on the stress stimuli involved and on many other factors including the gender of the individual.In rats, corticosterone and ACTH levels as well as functional activity of the hypothalmo-pituitary-adrenocortical axis are higher in females compared to males under both basal and stress conditions.Marked sex differences were observed in stress-induced changes in posterior pituitary hormone release.In male rats, release of vasopressin is not stimulated during stress conditions without an osmotic component while in female rats a rise in plasma vasopressin levels was observed even after short immobilization.Oxytocin release is enhanced in response to the majority of stress stimuli and it was found to be greater in females than in males.Mentioned gender differences are attributed to the effect of sex steriods, particularly those of estrogens.Not enough information is available on gender differences in neuroendocrine response during stress in humans.We observed a greater neutroendocrine activation in women than in men in response to heat exposure in sauna with pronounced differences in ACTH and prolactin release and partly also after a cold-pressor test.Understanding of gender differences in neuroendocrine response during stress might contribute to the explanation of the development of some emotional and other disorders with higher incidence in women.
Etiological, epidemiological and immunological conditions of human virus infections have been summarized. The main etiopathological aspects and basic etiological diagnostics of systemic infections were discassed with special reference to neurological, enteric, cardiac, pulmonary, ocular and sexually transmited infections. The importance of safety laboratory conditions was underlined.
Karyotypes (the number, shape, C-bands, NORs, chiasma frequency) of four species of Landrevinae were studied. Three species are characterized by a karyotype of 2n male=19 - Duolandrevus (Eulandrevus) sonorus, D. (E.) dendrophilus and D. (E.) enatus while Vasilia vietnamensis showed 2n=17. Differences of karyotypes are connected with simple Robertsonian translocation in autosomes. Successive stages of spermatogenesis were analysed.
As a part of ongoing cytogenetic studies on the jewel-beetles (Buprestidae, Coleoptera) of Armenia, the male karyotypes and meiosis of nine species (5 genera, 4 tribes, 2 subfamilies) are described, figured and discussed. In Ovalisia nadezhdae Sem., Sphenoptera artemisiae Reitt., Coraebus rubi L., C. sinuatus Creutz., Meliboeus caucasicus Reitt., Agrilus angustulus Ill. Men., A. obscuricollis Kiesw., and A. araxenus Khnz. diploid chromosome numbers vary in a narrow range from 20 to 24. In Sph. glabrata Men. a high chromosome number of 2n=40 was discovered. All the species have a XY sex chromosome system, which is however of different types. The data available on the buprestid karyotypes and karyotype variation at different taxonomic levels within the family are discussed.
Effects of early postnatal ethanol exposure on brain-derived neurotrophic factor (BDNF) mRNA expression in the rat hippocampus were investigated. Wistar rats were assigned to either ethanol treatment (ET), separation control (SC) or mother-reared control (MRC) groups. Ethanol exposure was achieved by a vapor inhalation method for 3 hours a day between postnatal days (PND) 10-15. On PND 16, 20, 30, and 60, the expression of BDNF mRNA in the hippocampus was determined using real-time RT-PCR analysis. There was a significant age-related increase in the BDNF mRNA expression between PND 3060 in MRC animals. The BDNF mRNA expression in ET rats was increased at both PND 16 and 20 and thereafter decreased at PND 60 compared to SC animals. Such age-related fluctuation in the expression of BDNF mRNA differed from that of MRC animals. The exact functional implications, if any, of these ethanol-induced changes in BDNF mRNA expression remain unknown although it can be speculated that they may have an effect on the behaviors known to be influenced by the hippocampal formation.
L-ascorbic acid is one of the basic vitamins, necessary to the normal growth and behaviour of organisms. The primary of this review is to present the chemical characteristics of this substance and to discuss its relation to various biological functions of vitamin C, mainly as an antioxidant barrier (we analysed product of reaction between phenothiazine derivative and L-ascorbic acid).
are proteinaceous infection particles. They are probably devoid of nucleic acid. (PrP) is encoded by the normal cellular gene. of prion protein has different conformation than the normal PrP protein. The exact nature of the posttranslational modification of prion protein is unknown. This modification may be caused by infection with prions infectious disease or occures spontaneously sporadic disease. Some mutations in PrP gene results in the production of pathological protein familial disease.
Interleukin-10 (IL-10) is produced predominantly by T-helper lymphocytes and macrophages.IL-10 inhibits lymphocyte-induced cytokine production (CSIF-cytokine synthesis inhibitory factor), cooperates in B-lymphocytes activation as well as macrophages- monocytes daectivation (MDF- macrophage deactivating factor). Due to its immunosupressive properties IL-10 may be used in the therapy of some T-cell induced disease.
Drugs able to inhibit calmodulin activation can prevent some consequences of the rise in intracellular calcium. It has recently been shown that intrathecal injection of calmodulin inhibitors induce analgesia in rats. We study here the effect induced by the calmodulin inhibitor, calmidazolium, on the activity of dorsal horn neurons driven by noxious and non-noxious stimuli. Extracellular recordings of convergent (n = 12), low-threshold mechanoreceptive (n = 5) and proprioceptive (n = 5) units were made in the presence of calmidazolium. Calmidazolium (600 mg) reduced the noxious (50oC) heat-evoked responses obtained in convergent neurons. On the contrary, the non-noxious tactile responses obtained in low-threshold mechanoreceptive neurons as well as the joint movement-evoked responses obtained in proprioceptive units remained unmodified. We conclude that calmidazolium can block nociceptive processing in the spinal cord and that this fact can help to explain the analgesic effects that intrathecal W-7 and calmidazolium induce in behavioral tests.
NO mediates many systemic reactions in humans and animals. It is produced by constitutive synthases (cNOS) and one inducible by cytokines and endotoxines (iNOS). We summarize, on the base of experimental and clinical data, the pathophysiological role of NO in septic shock as well as the effects of pharmacological application of NOS inhibitors. The analysed data show, that the contribution of NO to the pathomechanism of septic shock is rather heterogenous, therefore the clinical therapeutical application of selective iNOS inhibitors is impossible without adequate new monitoring tools.
We investigated cerebellar electrocortical activity before and after unilateral brain injury in anesthetized rats. Spectral analysis of cerebellar activity was obtained by Fast Fourier Transformation. There was a dominance of delta frequency range, while the wide gamma range presented no more than 5% of the total mean power spectra of cerebellar activity before brain injury. A few minutes after brain injury and within the first 90 minutes, there was a decrease of total mean power spectra and a relative decrease of delta range power to about 30%, some increase of beta range, and an increase of gamma range to 20?25%. Relative increase of gamma range in the cerebellar mean power spectra was still present 120 min after the brain injury, while other changes started to diminish. We suggest that spectral changes within slow and fast (gamma) frequency ranges of cerebellar activity may be indicators of the brain state after acute injury.
Streptozotocin (STZ) is a bacterial toxin which selectively damages both insulin-producing cells and insulin receptors. Injections of STZ into the cerebral ventricles of experimental animals are followed by sustained biochemical, metabolic and behavioral effects resembling those which are found in human brains afflicted by Alzheimer's disease. The aim of the present study was to assess the effects of double intracerebroventricular application of STZ on the ultrastructure of rat frontoparietal cortical neurons. The most prominent change, seen 3 weeks after STZ injection, was a significant enlargement of the Golgi apparatus caused by expansion of the trans-Golgi segment of the cellular protein secretory pathway. Morphometric analysis revealed that the area of the trans part of the Golgi complex in neuronal cells was increased more than two-fold (median values: 312 ? 103 nm3 in 14 neurons from control animals, and 846 ? 103 nm3 in 19 neurons from STZ-treated animals, P=0.0012), whereas that of the cis part did not significantly change. The effects of STZ did not resemble Golgi atrophy and fragmentation described in neurons from disease-prone brain structures of patients with Alzheimer's disease, but were similar to that observed after intravenous application of a non-metabolizable glucose analog 2-deoxyglucose. Considering that proamyloidogenic processing of beta-amyloid precursor protein may occur preferentially in the trans-Golgi segment, the observed early response of neuronal ultrastructure to desensitization of insulin receptors may predispose cells to form beta-amyloid deposits.
Several lines of evidence indicate that retinoids, derivates of vitamin A, affect reproductive function in birds, however, the mechanism of their action in the ovary is still unknown. Therefore, the present study was designed (i) to show whether in the domestic hen 9-cis retinoic acid (9-cis RA), one of the retinoids, influences steroid secretion in vitro by white and yellow chicken ovarian follicles, and (ii) to detect expression of retinoic acid RXR receptor mRNA in these follicles. The white follicles (small: 1-4 mm, medium: 4-6 mm and large 6-8 mm in diameter) and the three largest yellow preovulatory follicles (F3-F1; 25-37 mm) were isolated from the ovary 3 h before ovulation. The granulosa layer was separated from the theca layer in the preovulatory follicles, which were subsequently divided into 4 equal pieces. The isolated whole white follicles or parts of the granulosa or theca layers were incubated for 24 h at 38oC in Eagle's medium in the following 4 groups: control, ovine LH (oLH; 10 ng/ml), 9-cis RA (100 ng/ml) and 9-cis RA + oLH. After incubation, the medium was collected for estradiol (E2) and progesterone (P4) determination while tissues were saved for protein assay. It was found that 9-cis RA affects steroid secretion from chicken ovarian follicles. It decreased E2 secretion from white follicles and from the theca layer of the two largest (F2 and F1) preovulatory follicles. 9-cis RA had no effect on oLH-stimulated E2 secretion by the white follicles and yellow F2 and F1 follicles, but it diminished E2 secretion by F3 follicles. As regards P4, the effect of 9-cis RA was opposite; it increased P4 secretion from the granulosa layer of all preovulatory follicles. 9-cis RA did not change oLH-stimulated P4 secretion by granulosa layers of F3 and F2 follicles, however, it inhibited oLH-enhanced P4 secretion from the F1 granulosa layer. In a separate experiment, the presence of mRNA encoding RXR was found in the stroma and all follicles of the chicken ovary by means of the RT-PCR technique. The results indicate that retinoids, acting by specific nuclear receptors, are modulators of follicular steroidogenesis in the chicken ovary.