Showing papers by "Academy of Sciences of the Czech Republic published in 1999"
TL;DR: Environmental factors, including human activities, that enhance population densities of vector mosquitoes (heavy rains followed by floods, irrigation, higher than usual temperature, or formation of ecologic niches that enable mass breeding of mosquitoes) could increase the incidence of West Nile fever.
Abstract: West Nile virus causes sporadic cases and outbreaks of human and equine disease in Europe (western Mediterranean and southern Russia in 1962-64, Belarus and Ukraine in the 1970s and 1980s, Romania in 1996-97, Czechland in 1997, and Italy in 1998). Environmental factors, including human activities, that enhance population densities of vector mosquitoes (heavy rains followed by floods, irrigation, higher than usual temperature, or formation of ecologic niches that enable mass breeding of mosquitoes) could increase the incidence of West Nile fever.
1,028 citations
970 citations
TL;DR: Using optimized, asymmetric radiofrequency (RF) pulses for slice selection, the authors demonstrate that stimulated echo acquisition mode (STEAM) localization with ultra‐short echo time (1 ms) is possible, resulting in highly resolved in vivo 1H nuclear magnetic resonance spectra.
Abstract: Using optimized, asymmetric radiofrequency (RF) pulses for slice selection, the authors demonstrate that stimulated echo acquisition mode (STEAM) localization with ultra-short echo time (1 ms) is possible. Water suppression was designed to minimize sensitivity to B1 inhomogeneity using a combination of 7 variable power RF pulses with optimized relaxation delays (VAPOR). Residual water signal was well below the level of most observable metabolites. Contamination by the signals arising from outside the volume of interest was minimized by outer volume saturation using a series of hyperbolic secant RF pulses, resulting in a sharp volume definition. In conjunction with FASTMAP shimming (Gruetter Magn Reson Med 1993;29: 804-811), the short echo time of 1 msec resulted in highly resolved in vivo 1H nuclear magnetic resonance spectra. In rat brain the water linewidths of 11-13 Hz and metabolite singlet linewidths of 8-10 Hz were measured in 65 microl volumes. Very broad intense signals (delta v(1/2) > 1 kHz), as expected from membranes, for example, were not observed, suggesting that their proton T2 are well below 1 msec. The entire chemical shift range of 1H spectrum was observable, including resolved resonances from alanine, aspartate, choline group, creatine, GABA, glucose, glutamate, glutamine, myo-inositol, lactate, N-acetylaspartate, N-acetylaspartylglutamate, phosphocreatine, and taurine. At 9.4 T, peaks close to the water were observed, including the H-1 of alpha-D-glucose at 5.23 ppm and a tentative H-1 resonance of glycogen at 5.35 ppm.
897 citations
TL;DR: It is concluded that Cd36 deficiency underlies insulin resistance, defective fatty acid metabolism and hypertriglyceridaemia in SHR and may be important in the pathogenesis of human insulin-resistance syndromes.
Abstract: The human insulin-resistance syndromes, type 2 diabetes, obesity, combined hyperlipidaemia and essential hypertension, are complex disorders whose genetic basis is unknown. The spontaneously hypertensive rat (SHR) is insulin resistant and a model of these human syndromes. Quantitative trait loci (QTLs) for SHR defects in glucose and fatty acid metabolism, hypertriglyceridaemia and hypertension map to a single locus on rat chromosome 4. Here we combine use of cDNA microarrays, congenic mapping and radiation hybrid (RH) mapping to identify a defective SHR gene, Cd36 (also known as Fat, as it encodes fatty acid translocase), at the peak of linkage to these QTLs. SHR Cd36 cDNA contains multiple sequence variants, caused by unequal genomic recombination of a duplicated ancestral gene. The encoded protein product is undetectable in SHR adipocyte plasma membrane. Transgenic mice overexpressing Cd36 have reduced blood lipids. We conclude that Cd36 deficiency underlies insulin resistance, defective fatty acid metabolism and hypertriglyceridaemia in SHR and may be important in the pathogenesis of human insulin-resistance syndromes.
750 citations
Book•
13 Aug 1999TL;DR: In this paper, the authors studied the quality of post-communist democratic governance in four central and East European countries, including Czech Republic, Hungary, Slovenia, and Czechoslovakia.
Abstract: Acknowledgments Introduction Democracy and Party Competition Part I. Theory, Party Systems and the Procedural Quality of Post-Communist Democracy: 1. Historical legacies and strategies of democratization: pathways toward post-communist polities 2. The quality of post-communist democracy: patterns of party competition, interest representation and governance Part II. Setting and Research Strategy: 3. From communist rule to democracy: four central and East European countries 4. Empirical research strategy Part III. The Structuring of Party Competition: 5. Programmatic citizen-elite linkage strategies across post-communist polities 6. Linkage strategies within party systems: diversity among parties Part IV. Political Alignments and Dimensions of Competition: 7. Political divides and alignments: the politicians 8. Electoral constituency alignments: emerging political cleavages? Part V. Political Representation and the Quality of Democratic Governance: 9. Political representation 10. The governability of post-communist democracies: collation politics between passions and policy interests Part VI. Conclusion: 11. The diversity of post-communist democratic governance Appendices Bibliography.
671 citations
Journal Article•
TL;DR: The Win95 program for computation of distance matrixes and construction of phylogenetic or phenetic trees on the basis of RAPD, RFLP and allozyme data was presented and the program FreeTree can also assess the robustness of the tree topology by bootstrap, jackknife or OTU-jackknife analysis.
Abstract: The Win95 program for computation of distance matrixes and construction of phylogenetic or phenetic trees on the basis of RAPD, RFLP and allozyme data was presented. In contrast with other presently available software, the program FreeTree can also assess the robustness of the tree topology by bootstrap, jackknife or OTU-jackknife analysis. Moreover, the program can be used also for an analysis of data obtained in several independent experiments performed with nonidentical subsets of taxa. The function of the program was demonstrated by an analysis of RAPD data from 22 strains of Frenkelia. The program is available as an autoextractive archive containing the installation files of FreeTree and TreeView, manual in MS Word format and a sample of the input file at http://www.natur.cuni.cz/flegr/programs/+ ++freetree.
521 citations
TL;DR: It is demonstrated that it is possible to approximate the mutual information arbitrarily closely in probability by calculating the relative frequencies on appropriate partitions and achieving conditional independence on the rectangles of which the partitions are made.
Abstract: We demonstrate that it is possible to approximate the mutual information arbitrarily closely in probability by calculating the relative frequencies on appropriate partitions and achieving conditional independence on the rectangles of which the partitions are made. Empirical results, including a comparison with maximum-likelihood estimators, are presented.
482 citations
TL;DR: It was concluded that the current model is adequate to model photosynthesis in elevated [CO2], and the underlying biochemistry of photosynthesis was affected, as shown by a down-regulation of the parameters Jmax and Vcmax of the order of 10%.
Abstract: The effects of elevated atmospheric CO2 concentration on growth of forest tree species are difficult to predict because practical limitations restrict experiments to much shorter than the average life-span of a tree. Long-term, processbased computer models must be used to extrapolate from shorter-term experiments. A key problem is to ensure a strong flow of information between experiments and models. In this study, meta-analysis techniques were used to summarize a suite of photosynthetic model parameters obtained from 15 field-based elevated [CO2] experiments on European forest tree species. The parameters studied are commonly used in modelling photosynthesis, and include observed light-saturated photosynthetic rates (Amax), the potential electron transport rate (Jmax), the maximum Rubisco activity (Vcmax) and leaf nitrogen concentration on mass (Nm) and area (Na) bases. Across all experiments, light-saturated photosynthesis was strongly stimulated by growth in elevated [CO2]. However, significant down-regulation of photosynthesis was also observed; when measured at the same CO2 concentration, photosynthesis was reduced by 10‐20%. The underlying biochemistry of photosynthesis was affected, as shown by a down-regulation of the parameters Jmax and Vcmax of the order of 10%. This reduction in Jmax and Vcmax was linked to the effects of elevated [CO2] on leaf nitrogen concentration. It was concluded that the current model is adequate to model photosynthesis in elevated [CO2]. Tables of model parameter values for different European forest species are given.
462 citations
TL;DR: This review is focused upon contemporary information on the changes in leaf structure, water relations and photosynthesis during acclimatization of plantlets to ex vitro conditions and some ways of improving plant survival and for the speeding up of acclimation.
Abstract: The special conditions during in vitro culture result in the formation of plantlets of abnormal morphology, anatomy and physiology. After ex vitro transfer, these plantlets might easily be impaired by sudden changes in environmental conditions, and so need a period of acclimatization to correct the abnormalities. This review is focused upon contemporary information on the changes in leaf structure, water relations and photosynthesis during acclimatization of plantlets to ex vitro conditions. It also describes some ways of improving plant survival and for the speeding up of acclimatization.
414 citations
TL;DR: A new suboptimal search strategy for feature selection that represents a more sophisticated version of “classical” floating search algorithms and facilitates finding a solution even closer to the optimal one.
336 citations
TL;DR: The advantages of oriented immobilization of biologically active proteins are good steric accessibilities of active binding sites and increased stability, which not only may help to increase the production of preparative procedures but is likely to promote current knowledge about how the living cells or tissues operate.
TL;DR: Ion flux studies show that purified UCP2 and UCP3 behave identically to UCP1, and they catalyze electrophoretic flux of protons and alkylsulfonates, and proton flux exhibits an obligatory requirement for fatty acids.
TL;DR: A number of recently proposed preconditioning techniques based on sparse approximate inverses are considered, and an experimental comparison performed on one processor of a Cray C98 vector computer using sparse matrices from a variety of applications is presented.
TL;DR: It is shown for the first time that the inner mitochondrial membrane in human glioma cells contains a calcium-dependent K channel of the BK-type.
TL;DR: Recent results suggest that these membrane specializations mediate not only signal transduction via GPI-proteins and glycolipids but also play important roles in initiation of signalling via immunoreceptors.
TL;DR: To achieve small, stable complexes, the use of cationic polymers with short side chains bearing primary amino groups is suggested.
TL;DR: It is shown that the direct product of t-norms without zero divisors is again a t- norm without zero Divisors and that in the case of the real unit square, transformations by means of an automorphism preserve thedirect product structure.
TL;DR: The anti-hydrogen bond originates from the dispersive interaction between molecules (contrary to the hydrogen bond which is of electrostatic origin) in benzene-containing molecular clusters and is expected to be of consequence for the structure of biomolecules as discussed by the authors.
TL;DR: In this paper, the thickness and electrical properties of polyaniline hydrochloride films were determined by optical interferometry and linked to their optical absorption at the wavelength 400 nm, A 400 =(5.4±0.2)×10 −3 d f (in nm).
TL;DR: The morpho-ecological characteristics of staphylinid beetle adults and developmental stages are summarized, and features pertaining to their potential use as bioindicators are highlighted.
TL;DR: The results, which confirm and extend earlier observations, suggest that (TTAGG)n was a phylogenetically ancestral telomere motif in the insect lineage but was lost independently in different groups, being replaced probably by other telomeres motifs.
Abstract: We studied the occurrence of the TTAGG telomere repeats by fluorescence in-situ hybridization (FISH) and Southern hybridization in ten insect species and two other arthropods. (TTAGG)n-containing telomeres were found in three Lepidoptera species, the silkworm Bombyx mori (in which the telomeric sequence was recently discovered), the flour moth Ephestia kuehniella, and the wax moth Galleria mellonella, in one species of Hymenoptera, the honey bee Apis mellifera, in one species of Coleoptera, the bark beetle Ips typographus, in one species of Orthoptera, the locust Locusta migratoria, and in a crustacean, the amphipod Gammarus pulex. They were absent in another species of Coleoptera, the mealworm Tenebrio molitor, two representatives of Diptera, Drosophila melanogaster and Megaselia scalaris, a species of Heteroptera, the bug Pyrrhocoris apterus and a spider, Tegenaria ferruginea. Our results, which confirm and extend earlier observations, suggest that (TTAGG)n was a phylogenetically ancestral telomere motif in the insect lineage but was lost independently in different groups, being replaced probably by other telomere motifs. In the Coleoptera this must have happened rather recently as even members of the same family, Curculionidae, differ with respect to the telomeric DNA.
TL;DR: The age-dependent interactions of principal systems controlling the structure and function of the cardiovascular system in immature rats developing hypertension are outlined and critical periods (developmental windows) should be respected in the future pharmacological or gene therapy of human hypertension.
Abstract: In this review, we attempt to outline the age-dependent interactions of principal systems controlling the structure and function of the cardiovascular system in immature rats developing hypertensio...
TL;DR: Future studies of functional membrane alterations in hypertension or dyslipidemia will require the detailed determination of membrane lipid composition and the measurement of microviscosity in particular membrane domains.
TL;DR: Pregnancy outcome and semen studies imply that relatively low air pollution can significantly increase the adverse reproductive outcomes affecting both genders, and results indicate that air pollution may increase DNA damage in human population, which may be even higher for susceptible groups.
Abstract: The effect of environmental pollution on reproductive outcomes has been studied in the research project 'Teplice Program' analyzing the impact of air pollution on human health. Genotoxicity of urban air particles <10 microm (PM10) in in vitro system was determined by the analysis of DNA adducts. The highest DNA binding activity was observed in aromatic fraction, identifying DNA adducts of carcinogenic polycyclic aromatic hydrocarbons (PAHs) presumably diolepoxide-derived from: 9-hydroxybenzo[a]pyrene (9-OH-B[a]P), benzo[a]pyrene-r-7,-dihydrodiol-t-9,10-epoxide[+] (anti-BPDE), benzo[b]fluoranthene (B[b]F), chrysene (CHRY), benz[a]antracene (B[a]A), indeno[1,2,3-cd]pyrene (I[cd]P). Reproductive studies were conducted in both females and males. A study of the effects of PM10 exposure on pregnancy outcomes found the relationship between the intrauterine growth retardation (IUGR) and PM10 levels over 40 microg/m(3) in the first gestational month (Odds Ratio for 40-50 microg/m(3)50 microg/m(3)=1.9). Selected biomarkers were analyzed in venous blood, cord blood (chromosomal aberrations, comet assay) and placenta (DNA adducts, genetic polymorphisms of GSTM1 and NAT2 genotypes) of women enrolled in a nested case-control study. DNA adduct levels were higher in polluted vs. control districts, in smoking vs. nonsmoking mothers, and in GSTM1 null genotype, which was more pronounced in polluted district. No effect of air pollution was observed by cytogenetic analysis of chromosomal aberrations or by comet assay. The reproductive development of young men was followed by measures of semen quality, adjusted for ambient SO(2) exposure. The analysis identified significant associations with air pollution for <13% morphologically normal sperm, <29% sperm with normal head shape, <24% motile sperm. Analysis of aneuploidy in human sperm by FISH showed, aneuploidy YY8 was associated with season of heaviest air pollution. These findings are suggestive for an influence of air pollution on YY8 disomy. All these results indicate that air pollution may increase DNA damage in human population, which may be even higher for susceptible groups. Biomarkers of exposure (DNA adducts) and susceptibility (GSTM1 and NAT2) may indicate the risk of presumable low environmental exposure. Pregnancy outcome and semen studies imply that relatively low air pollution (higher than 40 microg PM10/m(3)) can significantly increase the adverse reproductive outcomes affecting both genders.
TL;DR: In this paper, a method of monitoring the spatial distribution of pollution due to airborne solid particles based on measurements of magnetic susceptibility of the soil surface near a brown-coal-burning power plant is presented.
TL;DR: In this article, the electron density of C−H···π complexes has been determined for a series of H−Hπ complexes, which exhibit either anti-H bond or normal H bond character.
Abstract: The theory of atoms in molecules is used to examine the nature of anti-hydrogen bond (anti-H bond) interaction. Contrary to what is found in normal hydrogen bond (H bond) complexes, which are characterized by lengthening of the X−H bond and a red shift of its stretching frequency, the anti-H bond leads to a shortening of the X−H bond length and a blue shift of its vibrational frequency. The topological properties of the electron density have been determined for a series of C−H···π complexes, which exhibit either anti-H bond or normal H bond character, as well as for the complexes C6H5F···HCCl3 and C6H6···HF, which are representative cases of anti- and normal H bonds. Inspection of the set of topological criteria utilized to characterize conventional H bonds shows no relevant difference in the two classes of H···π complexes. Analysis of the results suggests that the specific features of the anti-H bond originates from the redistribution of electron density in the C−H bond induced upon complexation, which i...
TL;DR: An electrodynamic theory of GMI, based on a simultaneous solution of linearized Maxwell's equations and Landau-Lifshitz equation of motion, is presented in this paper.
TL;DR: Control of many important parasitic diseases is still far from being satisfactory and further research is needed, but studies on immunity in parasitic infections, use of molecular technology in diagnostics and development of new vaccines against the most pathogenic parasites are very promising.
TL;DR: In this paper, several statistical downscaling methods and large-scale predictors are evaluated to determine daily mean temperatures at 39 stations in central Europe, including 500 hPa heights, sea level pressure, 850 hPa temperature and 1000-500 hPa thickness.
Abstract: Several statistical downscaling methods and large-scale predictors are evaluated to ascer- tain their potential to determine daily mean temperatures at 39 stations in central Europe. The methods include canonical correlation analysis, singular value decomposition, and 3 multiple regression models. The potential large-scale predictors are 500 hPa heights, sea level pressure, 850 hPa temperature and 1000-500 hPa thickness. The performance of the methods is evaluated using cross-validation and root- mean-squared error as a measure of accuracy. The stepwise screening of gridpoint data is found to be the statistical model that performed the best. Among the predictors, temperature variables yield more accurate results than circulation variables. The best predictor is the combination of 500 hPa heights and 850 hPa temperature. Geographical variations of the specification skill, mainly the differences between the elevated and lowland stations, are also discussed.
TL;DR: The results point to a unique profile of DNA binding for BBR3464, strengthening the original hypothesis that modification ofDNA binding in manners distinct from that of cisplatin will also lead to a distinct and unique profileof antitumor activity.
Abstract: The DNA-binding profile of a novel, trinuclear platinum Phase I clinical agent (BBR3464) is summarized. The structure of BBR3464 is best described as two trans-[PtCl(NH3)2] units linked by a tetra-amine [trans-Pt(NH3)2{H2N(CH2)6NH2}2]2+ unit. The +4 charge of BBR3464, the presence of at least two Pt coordination units capable of binding to DNA, and the consequences of such DNA binding are remarkable departures from the cisplatin structural paradigm. The chemical and biological features argue that the drug should be considered the first clinical representative of an entirely new structural class of DNA-modifying anticancer agents. The high charge on BBR3464 facilitates rapid binding to DNA with a t1/2 of approximately 40 min, significantly faster than the neutral cisplatin. The melting temperature of DNA adducted by BBR3464 increased at low ionic strength but decreased in high salt for the same rb. This unusual behavior is in contrast to that of cisplatin. BBR3464 produces an unwinding angle of 14 degrees in negatively supercoiled pSP73 plasmid DNA, indicative of bifunctional DNA binding. Quantitation of interstrand DNA-DNA cross-linking in plasmid pSP73 DNA linearized by EcoRI indicated approximately 20% of the DNA to be interstrand cross-linked. While this is significantly higher than the value for cisplatin, it is, interestingly, lower than that for dinuclear platinum compounds such as [{trans-PtCl(NH3)2}2H2N(CH2)6NH2]2+ (BBR3005) where interstrand cross-linking efficiency may be as high as 70-90%. Either the presence of charge in the linker backbone or the increased distance between platinating moieties may contribute to this relatively decreased ability of BBR3464 to induce DNA interstrand cross-linking. Fluorescence experiments with ethidium bromide were consistent with the formation of long-range delocalized lesions on DNA produced by BBR3464. The sequence preference for BBR3464 on plasmid DNA was determined to the exact base pair by assaying extension of the polynucleotide by VentR(exo+) DNA polymerase. Strong sequence preference for single dG or d(GG) sites was suggested. The presence of relatively few blocks on DNA in comparison to either cisplatin or BBR3005 was indicative of high sequence selectivity. The following appropriate sequence where stop sites occur was chosen: [sequence: see text] molecular modeling on 1,4 interstrand (G'30 to G33) and 1,5 intrastrand (G33 to G29) cross-links further confirmed the similarity in energy between the two forms of cross-link. Finally, immunochemical analysis confirmed the unique nature of the DNA adducts formed by BBR3464. This analysis showed that antibodies raised to cisplatin-adducted DNA did not recognize DNA modified by BBR3464. In contrast, DNA modified by BBR3464 inhibited the binding of antibodies raised to transplatin-adducted DNA. Thus, the bifunctional binding of BBR3464 contains few similarities to that of cisplatin but may have a subset of adducts recognized as being similar to the transplatinum species. In summary, the results point to a unique profile of DNA binding for BBR3464, strengthening the original hypothesis that modification of DNA binding in manners distinct from that of cisplatin will also lead to a distinct and unique profile of antitumor activity.