Experimental infection of the pulmonate snails Arianta arbustorum L. and Helix pomatia L. with first-stage larvae of protostrongylid nematode Elaphostrongylus cervi Cameron, 1931 was performed in order to determine modes of larval entry into the body of the snail intermediate host. Groups by four individuals of both snail species were examined histologically 30, 60, 90, and 120 minutes after the beginning of exposure and 1, 2, 4, and 7 days post infection. All 64 snails examined were found to be successfully infected. The superficial furrows of the sole were recognized as the most important site of larval entry into the snail organism. Larval penetration was observed to be accompanied by destruction of the superficial epithelium. The number of larvae found in the subepithelial connective tissue of the headfoot was significantly higher than that found in other tissues and organs. Larval counts in individual parts of the body of snails examined from 0 to 7 days p.i. did not fluctuate significantly. The present results indicate that only those protostrongylid larvae which actively penetrated the superficial epithelium of the snail sole play an important role in the life cycle.
Arsenic, antimony and selenium belong to toxic contaminants with high environmental risk. In contrast to metal cationic contaminants (Be, Zn, Cd, Hg Pb, etc.) the metalloids and nonmetals of groups 5 and 6 of periodic system generally form the oxyanions in two oxidizing states (i.e. arsenates and arsenites, antimonates and antimonites, as well as selenates and selenites) in dependence on redox potential and pH value. It is well known that above mentioned oxyanions have a strong adsorption affinity to hydrated oxides and/or oxides hydroxides of Fe, Al and Mn, preferably Fe forming stable surface complexes. In fact, commercially produced Fe oxides-based sorbents are too expensive for strongly contaminated aqueous systems. Aluminosilicates have opened new possibilities in sorption technology due to favourable surface properties, availability, environmental and economical reasons, but they are not selective sorbents of anionic contaminants thanks to a low pHZPC. A simple Fe/Al/Mn pre-treatment of raw aluminosilicates can significantly improve their sorption affinity to oxyanionic contaminants, including arsenites and arsenates, selenites and selenates and antimonites and antimonates, respectively. Different types of natural and/or second-rate clays (metakaolines with the large content of Fe, raw bentonites and natural clinoptilolite-rich tuff, ) from Central European localities were used for FeII, FeIII, AlIII and MnII pre-treatment., Barbora Doušová, Lucie Fuitová, Lenka Herzogová, Tomáš Grygar, David Koloušek and Vladimír Machovič., and Obsahuje bibliografii
Mediální dialog ztrácí některé rysy přirozeného dialogu tváří v tvář, který leží v jeho půdorysu, a získává rysy další, neboť komunikace tu přestupuje přes hranice primární řečové situace. Televizní dialog je dialog veřejný, který se vede před diváckým publikem a pro toto publikum. Divák je nejen svědkem, ale pravým cílem, k němuž je dialog směrován. Stať analyzuje komunikační situaci, při níž jsou ve studiu přítomni redaktor a dva hosté, představitelé různých profesí a názorových proudů (ekonom a ekoložka) i různých stanovisek k určité otázce (globalizace). Redaktor se obrací s otázkami střídavě k oběma. aby je vzájemně konfrontoval a spor vyhrotil. Dotazovaní hosté se snaží nejen odpovídat na otázky redaktora (to je jejich základní role v interview), ale i zpochybňovat či přímo vyvracet odpovědi druhého z hostí (role často neméně důležitá). Hosté komunikují nejen s redaktorem, ale komunikují i mezi sebou navzájem, ať už skrytě, či zjevně, s cílem získat diváka na svou stranu. Stať analyzuje toto interview v souvislosti s otázkou typologie debat a debat založených na konfliktu zájmů a konfliktu hodnot.
Taking into consideration the biological importance of interaction between antioxidant defense (AD) enzymes and sexual steroid hormones it was deemed important to compare our recent achievements in the field with the state of current knowledge. The main goal of the present review was to investigate the changes of AD enzyme activities: superoxide dismutases, catalase, glutathione peroxidase, glutathione-S-transferase and glutathione reductase in the brain of female and male rats depending on progesterone and estradiol. These ovarian steroids produce their effects by acting on numerous target tissues and organs, such as the reproductive organs, bone tissue and cartilage, peripheral blood vessels and the central nervous system (CNS). We have chosen it as a new parameter that might represent an important indicator of the changes within the CNS, bearing in mind the biological importance of the enzymes of the AD system. Our experimental results indicate that the AD enzyme activities in the brain tissue of female and male rats show a certain dependence on the concentration of progesterone and estradiol. The present review suggests that the modulation of the oxidative and antioxidative capacity by sexual steroid hormones is mediated through antioxidant metabolizing enzymes., S. B. Pajović, Z. S. Saičić., and Obsahuje bibliografii a bibliografické odkazy
Previous data suggest that type 1 diabetes mellitus leads to the deterioration of myocardial intercellular communication mediated by connexin-43 (Cx43) channels. We therefore aimed to explore Cx43, PKC signaling and ultrastructure in non -treated and omega-3 fatty acid (omega-3) treated spontaneously diabetic Goto-Kakizaki (GK) rats considered as type 2 diabetes model. Four-week-old GK and non-diabetic Wistar-Clea rats were fed omega -3 (200 mg/kg/day) for 2 months and compared with untreated rats. Realtime PCR and immunoblotting were performed to determine Cx43, PKC- epsilon and PKC-delta expression. In situ Cx43 was examined by immunohistochemistry and subcellular alterations by electr on microscopy. Omega-3 intake reduced blood glucose, triglycerides, and cholesterol in diabetic rats and this was associated with improved integrity of cardiomyocytes and capillaries in the heart. Myocardial Cx43 mRNA and protein levels were higher in diab etic versus non- diabetic rats and were further enhanced by omega-3. The ratio of phosphorylated (functional) to non-phosphorylated Cx43 was lower in diabetic compared to non- diabetic rats but was increased by omega-3, in part due to up -regulation of PKC-epsilon. In addition, proapoptotic PKC-delta expression was decreased. In conclusion, spontaneously diabetic rats at an early stage of disease benefit from omega-3 intake due to its hypoglycemic effect, upregulation of myocardial Cx43, and preservation of cardiovascular ultrastructure. These findings indicates that supplementation of omega-3 may be beneficial also in the management of diabetes in humans., J. Radosinska, L. H. Kurahara, K. Hiraishi, C. Viczenczova, T. Egan Benova, B. Szeiffova Bacova, V: Dosenko, J. Navarova, B. Obsitnik, I. Imanaga, T. Soukup, N. Tribulova., and Obsahuje bibliografii
Acute promyelocytic leukemia is characterized by a block of myeloid differentiation. The incubation of cells with 1 μmol/l all-trans retinoic acid (ATRA) for 72 h induced differentiation of HL-60 cells and increased the number of CD11b positive cells. Morphological and functional changes were accompanied by a loss of proliferative capacity. Differentiation caused by preincubation of leukemic cells HL-60 with ATRA is accompanied by loss of clonogenicity (control cells: 870 colonies/103 cells, cells preincubated with ATRA: 150 colonies/103 cells). D0 for undifferentiated cells was 2.35 Gy, for ATRA differentiated cells 2.46 Gy. Statistical comparison of clonogenity curves indicated that in the whole range 0.5-10 Gy the curves are not significantly different, however, in the range 0.5-3 Gy ATRA differentiated cells were significantly more radioresistant than non-differentiated cells. When HL-60 cells preincubated with 1 μmol/l ATRA were irradiated by a sublethal dose of 6 Gy, more marked increase of apoptotic cells number was observed 24 h after irradiation and the surviving cells were mainly in the G1 phase of the cell cycle, while only irradiated cells were accumulated in G2 phase. Our results imply that preincubation of cells with ATRA accelerates apoptosis occurrence (24 h) after irradiation by high sublethal dose of 6 Gy. Forty-eight hours after 6 Gy irradiation, late apoptotic cells were found in the group of ATRA pretreated cells, as determined by APO2.7 positivity. This test showed an increased effect (considering cell death induction) in comparison to ATRA or irradiation itself., M. Mareková, J. Vávrová, D. Vokurková, J. Psutka., and Obsahuje bibliografii
Urocortin 2 (UCN2) is a peptide related to corticotropin-releasing factor, capable of activating CRF-R2. Among its multisystemic effects, it has actions in all 3 muscle subtypes. This study’s aim was to determine its potential role in two of the intrinsic eye muscle kinetics. Strips of iris sphincter (rabbit) and ciliary (bovine) muscles were dissected and mounted in isometric forcetransducer systems filled with aerated-solutions. Contraction was elicited using carbachol (10-6 M for iris sphincter, 10-5 M for ciliary muscle), prior adding to all testing substances. UCN2 induced relaxation in iris sphincter muscle, being the effect maximal at 10-7 M concentrations (-12.2 % variation vs. control). This effect was abolished with incubation of indomethacin, antisauvagine-30, chelerytrine and SQ22536, but preserved with L-nitro-L-arginine. In carbachol pre-stimulated ciliary muscle, UCN2 (10-5 M) enhanced contraction (maximal effect of 18.2 % increase vs. control). UCN2 is a new modulator of iris sphincter relaxation, dependent of CRF-R2 activation, synthesis of prostaglandins (COX pathway) and both adenylate cyclase and PKC signaling pathways, but independent of nitric oxide production. Regarding ciliary muscle, UCN2 enhances carbachol-induced contraction, in higher doses., M. Tavares-Silva, D. Ferreira, S. Cardoso, A. R. Raimundo, J. Barbosa-Breda, A. Leite-Moreira, A. Rocha-Sousa., and Obsahuje bibliografii
The acute effects of β-adrenergic stimulation on myocardial stiffness were evaluated. New-Ze aland white rabbits were treated with saline (control group) or do xorubicin to induce heart failure (HF) (DOXO-HF group). Effects of isoprenaline (10-10-10-5 M), a non-selective β-adrenergic agonist, were tested in papillary muscles from both groups. In the control group, the effects of isoprenaline were also evaluate d in the presence of a damaged endocardial endothelium, atenolol (β1-adrenoceptor antagonist), ICI-118551 (β2-adrenoceptor antagonist), KT-5720 (PKA inhibitor), L-NNA (NO-synthase inhibitor), or indomethacin (cyclooxygenase inhibitor). Passive length-tension relations were constructed before and after adding isoprenaline (10-5 M). In the control group, isoprenaline increased resting muscle length up to 1.017±0.006 L/Lmax. Correction of resting muscle length to its initial value resulted in a 28.5±3.1 % decrease of resting tension, indicating decreased muscle stiffness, as confirmed by the isoprenaline-induced right-downwa rd shift of the passive length- tension relation. These effects were modulated by β1- and β2-adrenoceptors and PKA. In DOXO-HF group, the effect on myocardial stiffness was significantly decreased. We conclude that β -adrenergic stimulation is a relevant mechanism of acute neurohumoral modulation of the diastolic function. Furthermore, this study clarifies the mechanisms by which myocardial stiffness is decreased., I. Falcão-Pires ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Dipeptidyl peptidase-IV (DPP-IV, CD26) is a serine protease almost ubiquitously expressed on cell surface and present in body fluids. DPP-IV has been suggested to proteolytically modify a number of biologically active peptides including substance P (SP) and the chemokine stro mal cell derived factor-1α (SDF-1α, CXCL12). SP and SDF-1α have been implicated in the regulation of multiple biological processes and also induce responses that may be relevant for glioma progression. Both SP and SDF-1α are signaling through cell surface receptors and use intracellular calcium as a second messenger. The effect of DPP-IV on intracellular calcium mobilization mediated by SP and SDF- α was monitored in suspension of wild type U373 and DPP-IV transfected U373DPPIV glioma cells using indicator FURA-2. Nanomolar concentrations of SP triggered a transient dose dependent increase in intracellular calcium rendering the cells refractory to repeated stimulation, while SDF-1α had no measurable effect. SP signaling in DPP-IV overexpressing U373DPPIV cells was not substantially different from that in wild type cells. However, preincubation of SP with the DPP-IV overexpressing cells lead to the loss of its signaling potential, which could be prevented with DPP-IV inhibitors. Taken together, DPP-IV may proteolytically inactivate local mediators involved in gliomagenesis., P. Bušek, J, Stremeňová, E. Křepela, A. Šedo., and Obsahuje bibliografii a bibliografické odkazy
We aimed to explore the effects of melatonin and n-3 polyunsaturated fatty acids (PUFA) supplementation on plasma and aortic nitric oxide (NO) levels in isoproterenol (Iso) affected spontaneously hypertensive (SHR) and Wistar rats. Untreated control rats were compared with Iso injected (118 mg/kg, s.c.) rats, and Iso injected plus supplemented with melatonin (10 mg/kg, p.o.) or PUFA (1.68 g/kg, p.o.) for two months. Plasma and aortic basal, L-NAME inhibited, adrenaline and acetylcholine stimulated NO were determined using Griess method. Plasma NO levels were lower in SHR versus Wistar rats. Iso decreased NO in Wistar while not in SHR. PUFA but not melatonin intake of Iso treated SHR increased plasma NO along with a decrease in systolic blood pressure. Basal aortic NO level was higher in SHR than Wistar rats and not altered by Iso. Intake of melatonin increased but PUFA decreased basal NO levels in Wistar+Iso and did not affect in SHR+Iso rats. Acetylcholine and adrenaline induced aortic NO release was significantly increased in Wistar+Iso but not SHR+Iso group. Melatonin intake increased Ach induced aortic NO in Wistar+Iso and SHR+Iso groups, whereas there was no effect of PUFA intake. Findings suggest that PUFA modulates plasma and melatonin aortic NO levels of isoproterenol affected rats in a strain-dependent manner., K. K. Chaudagar, C. Viczenczova, B. Szeiffova Bacova, T. Egan Benova, M. Barancik, N. Tribulova., and Obsahuje bibliografii