A number of clinical neurological pathologies are associated with increased permeability of the blood brain barrier (BBB). Induced changes of the homeostatic mechanisms in the brain microenvironment lead among others to cellular changes in the CNS. The question was whether some of these changes can be induced by osmotic opening of BBB in an in vivo experiment and whether they can be detected in cerebrospinal fluid (CSF). CSF was taken via the suboccipital puncture from 10 healthy rats and six rats after the osmotic opening of the BBB. In all 16 animals, concentration of myelin basic protein (MBP ng/ml), Neuron-specific enolase (NSE ng/ml) and Tau-protein (Tau pg/ml) were determined in CSF by ELISA. Values in both groups were statistically evaluated. Significant difference between the control and experimental group was revealed only for the concentration of myelin basic protein (p<0.01). The presented results indicate that osmotic opening of the BBB in vivo experiment without the presence of other pathological conditions of the brain leads to a damage of myelin, without impairment of neurons or their axons., P. Kozler, O. Sobek, J. Pokorný., and Obsahuje bibliografii
In some patients, heart failure (HF) is associated with increased pulmonary vascular resistance (PVR). The magnitude and the reversibility of PVR elevation affect the HF management. Sildenafil has been recently recognized as potent PVR-lowering drug in HF. The aim of the study was to compare hemodynamic effects and pulmonary selectivity of sildenafil to prostaglandin E1(PGE1). Right-heart catheterization was performed in 13 euvolemic advanced HF patien ts with elevated PVR (6.3±2 Wood's units). Hemodynamic parameters were measured at the baseline, during i.v. infusion of PGE1 (alprostadil 200 ng·kg-1·min-1 ) and after 40 mg oral do se of sildenafil. Both drugs similarly reduced systemic vascular resistance (SVR), but sildenafil had higher effect on PVR (-28 % vs. -49 %, p=0.05) and transpulmonary pressu re gradient than PGE1. The PVR/SVR ratio - an index of pulmonary se lectivity, did not change after PGE1(p=0.7) but it decreased by -32 % (p=0.004) after sildenafil. Both drugs similarly reduced pulmonary artery mean and wedge pressures and increa sed cardiac index (+27 % and +28 %). Sildenafil led more often to transplant-acceptable PVR while causing smaller drop of mean systemic pressure than PGE1. In conclusion, vasodilatatory effects of sildenafil in patients with heart failure are more pronounced in pulmonary than in systemic circulation., H. Al-Hiti ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Galleria mellonella larvae spin protective tubes, which they use until they finish feeding, when they spin cocoons. A feeding choice experiment showed that some of the silk produced by feeding larvae was consumed in addition to the standard diet (STD). To determine the effect of feeding on silk, last instar larvae were fed for 24 h on foods based on STD but modified by replacing the dry milk component (10% of the diet) with equal amounts of different kinds of silk. While each control larva consumed 21 ± 0.5 mg of the STD and produced 4.5 ± 0.1 mg of silk, larvae that ate the food that contained larval silk consumed 10 ± 0.4 mg of food and produced 6.1 ± 0.1 mg silk; the percentage ratio of silk produced to diet consumed was 21% and 61%, respectively. A more pronounced reduction in food consumption occurred when larvae were supplied with Galleria "cocoon" silk or the sericin fraction of such silk, and only 3.8 mg/larva was ingested of the diet containing Bombyx mori cocoon silk or its sericin fraction. Silk production expressed in terms of percentage of diet consumed was always higher than that recorded for larvae fed STD. We conclude that G. mellonella larvae recycle part of the silk that they produce during feeding. Presence of silk in the diet reduces food intake but increases the ratio of silk production to diet consumption. Sericin fraction of the cocoon silk seems to deter feeding., Haq Abdul Shaik, Archana Mishra, František Sehnal., and Obsahuje bibliografii
Silové působení světla na objekty je registrováno patrně od 17. století, kdy Johanes Kepler zmínil tento mechanismuus na základě pozorování odklonu chvostů komet od Slunce. Od této ukázky radiačního tlaku našly silové účinky světla řadu podob a aplikací ve všech přírodních vědách - od zachycení mikroorganismů ve fokusovaném laserovém svazku přes optická síta ke třídění částic, chlazení pohybu nanočástic až po stabilizaci orientace satelitu Kepler (jak zajímavá historická shoda). V předkládaném článku se zaměříme na chování nanočástic a mikročástic nekulového tvaru ozářených laserovými svazky různých vlastností., A force interaction between light and objects has been suggested since the 17th century when Johannes Kepler proposed this mechanism after observing comet tails which deviate from the Sun. Since this initial example of radiation pressure, the force interaction between light and objects has found many forms and applications in sciences - from trapping of microorganisms in a focused laser beam to optical sieves for particle sorting to cooling of nanoparticles motion or orientation stabilisation of the Kepler satellite (an interesting historical coincidence). In this contribution we will focus on the behaviour of nanoparticles and microparticles with a non-spherical shape illuminated by laser beams of various properties., Pavel Zemánek, Petr Jákl, Oto Brzobohatý., and Obsahuje seznam literatury
Vermiculite (V) from Brazil with aqueous solutions AgNO3 and/or Cu(NO3)2 was used for preparation of nanocomposites V/Ag, V/Cu, V/AgCu and V/CuAg using two procedures and their effect on bacteria was compared. Structural changes were evaluated using X-ray diffraction (XRD) analysis, Infrared spectroscopy (IRS) and Scanning electron microscopy (SEM). Elemental chemical composition was determined using X-ray fluorescence (XRF) analysis and the solutions were analyzed by Atomic emission spectroscopy with inductively coupled plasma (AES-ICP). Antibacterial properties of Ag- and Cu-vermiculites and combined Ag/Cu-vermiculites were tested on two bacteria groups: (1) Gram-positive, G+, (Staphylococcus aureus and Enterococcus faecalis) and (2) Gram-negative, G-, (Pseudomonas aeruginosa and Klebsiella pneumoniae). The samples under antibacterial testing showed different effective times and minimum inhibitory concentration (MIC) values. The Gram-negative bacteria showed higher sensitivity to the prepared samples than Gram-positive bacteria. The combined Cu/Ag vermiculites stopped the bacterial growth at lower MIC value., Marianna Hundáková, Marta Valášková, Vladimír Tomášek, Erich Pazdziora and Kateřina Matějová., and Obsahuje bibliografii
Ischemic postconditioning and remote conditioning are potentially useful tools for protecting ischemic myocardium. This study tested the hypothesis that 2,3-dehydrosilybin (DHS), a flavonolignan component of Silybum marianum , could attenuate cardiomyocyte damage following hypoxia/ reoxygenation by decreasing the generation of reactive oxygen species (ROS). After 5-6 days of cell culture in normoxic conditions the rat neonatal cardiomyocytes were divided into four groups. Control group (9 h at normoxic conditions), hypoxia/ reoxygenation group (3 h at 1 % O2 , 94 % N2 and 5 % CO2 followed by 10 min of 10 μmol·l -1 DHS and 6 h of reoxygenation in normoxia) and postconditioning group (3 h of hypoxia, three cycles of 5 min reoxygenation and 5 min hypoxia followed by 6 h of normoxia). Cell viability assess ed by propidium iodide staining was decreased after DHS treatment consistent with increased levels of lactatedehydrogenase (LDH) after reoxygenation. LDH leakage was significantly reduced when cardiomyocytes in the H/Re group were exposed to DHS. DHS treatment reduced H2O2 production and also decreased the generation of ROS in the H/Re group as evidenced by a fluorescence indicator. DHS treatment reduces reoxygenation-induced injury in cardiomyocytes by attenuation of ROS generation, H2O2 and protein carbonyls levels. In addition, we found that both the postconditioning protocol and the DHS treatment are associated with restored ratio of phosphorylated/total protein kinase C epsilon, relative to the H/Re group. In conclusion, our data support the protective role of DH S in hypoxia/reperfusion injury and indicate that DHS may act as a postconditioning mimic., E. Gabrielová, V. Křen, M. Jabůrek, M. Modrianský., and Obsahuje bibliografii
Action of antiepileptic drugs in immature brain may differ from that in adult brain. The aim of our study was to study an anticonvulsant action of lamotrigine and phenytoin, i.e. two drugs active against partial seizures in adult experimental animals as well as human patients, in a model of simple partial seizures in immature rats. Epileptic foci were induced by local application of bicuculline methiodide on sensorimotor cortical area of 12-dayold rat pups. The animals were pretreated with lamotrigine (LTG, 10 or 20 mg/kg i.p.) or phenytoin (PHT, 15, 30 or 60 mg/kg i.p.). Control rats for LTG received saline, controls for PHT solvent composed of propyleneglycol, ethanol and water. Influence of either drug on interictal activity was negligible. High doses of both LTG and PHT suppressed the transition into ictal phases and shortened the duration of persisting seizures. The tricomponent solvent exhibited moderate activity against ictal activity if compared with saline controls. The two drugs exhibited similar action in our model, i.e. the suppression of secondary generalization from epileptic focus. This action is comparable to that described for human patients and adult experimental animals. In favor of lamotrigine speaks the absence of serious side effects., K. Bernášková, P. Mareš., and Obsahuje bibliografii a bibliografické odkazy
Aerobic exercise showed beneficial influence on cardiovascular systems in aging, and mechanisms underlying vascular adaption remain unclear. Large-conductance Ca2+ -activated K+(BKCa) channels play critical role s in regulating cellular excitability and vascular tone. This study determin ed the effects of aerobic exercise on aging -associated functional changes in BK Ca channels in cerebrovascular myocytes, Male Wistar rats aged 20- 22 mo nths were randomly assigned to sedentary (O -SED), low training frequency (O-EXL), and high training frequency group (O -EXH). Young rats were used as control. Compared to young rats, w hole -cell BK Ca current was decreased, and amplitude of spontaneous transient outward currents were reduced. The open probability and Ca2+/voltage sensitivity of single BK Ca channel were declined in O -SED, accompanied with a reduction of tamoxifen-induced BK Ca activation; the mean open time of BK Ca channels was shortened whereas close time was prolonged. Aerobic exercise training markedly alleviated the aging-associated decline independent of training frequency. Exercise three times rather than five times weekly may be a time and cost-saving training volume required to offer bene ficial effects to offset the functional declines of BK Ca during aging., Na Li, Bailin Liu, Sharon Xiang, Lijun Shi., and Obsahuje bibliografii
The objective of this study was to determine if primers, probes, and pHCl, a plasmid containing a 2.3 kilobasc insert of genomic DNA from Cryptosporidium parvum, would be useful for the detection of Cryptosporidium wrairi DNA using the polymerase chain reaction. C. wrairi DNA was prepared from oocysts recovered from guinea pigs and C. parvum DNA was prepared from the Iowa strain of C. parvum. Two 26-(bp) primers were used to amplify a 452-base pair bp target sequence within the cloned DNA. Similarly-sized PCR products were obtained with the pHCl plasmid DNA, C. parvum DNA, and C. wrairi DNA. However, a 20-base pair probe did not detect C. wrairi DNA. Sequencing of C. wrairi DNA homologous with the 452-bp segment of C. parvum DNA showed 18 bp changes including bp changes in the segment homologous with the probe. A new probe based on homologous sequences was useful for detection of both species of Cryptosporidia. The sequences of the homologous 452-bp segment from the Iowa strain of C. parvum and that segment of C. parvum DNA from the pHC I plasmid were very similar. Nine base pairs identical in the homologous bp segment of the Iowa strain of C. parvum, C. wrairi and the pHCl plasmid differed from those previously reported. Previously reported primers and a newly designed probe proved to be useful for detecting C. wrairi DNA.
Oxidation kinetics of celulose, lignin, brown coal, and their mixtures were investigated. Using non-linear regression method kinetic parameters from thermogravimetric curves were calculated for oxidation of volatile matter and fixed carbon (char). The presence of the cellulose in the mixture affects the rate constant of lignin and brown coal oxidation which was determined by means of Arrhenius plots., Petr Šušák, Silvie Vallová and Juraj Leško., and Obsahuje bibliografii