BACKGROUND AND OBJECTIVE: The geodesic ray-tracing method has shown its effectiveness for the reconstruction of fibers in white matter structure. Based on reasonable metrics on the spaces of the diffusion tensors, it can provide multiple solutions and get robust to noise and curvatures of fibers. The choice of the metric on the spaces of diffusion tensors has a significant impact on the outcome of this method. Our objective is to suggest metrics and modifications of the algorithms leading to more satisfactory results in the construction of white matter tracts as geodesics. METHODS: Starting with the DTI modality, we propose to rescale the initially chosen metric on the space of diffusion tensors to increase the geodetic cost in the isotropic regions. This change should be conformal in order to preserve the angles between crossing fibers. We also suggest to enhance the methods to be more robust to noise and to employ the fourth order tensor data in order to handle the fiber crossings properly. RESULTS: We propose a way to choose the appropriate conformal class of metrics where the metric gets scaled according to tensor anisotropy. We use the logistic functions, which are commonly used in statistics as cumulative distribution functions. To prevent deviation of geodesics from the actual paths, we propose a hybrid ray-tracing approach. Furthermore, we suggest how to employ diagonal projections of 4th order tensors to perform fiber tracking in crossing regions. CONCLUSIONS: The algorithms based on the newly suggested methods were succesfuly implemented, their performance was tested on both synthetic and real data, and compared to some of the previously known approaches.

• MeSH
• algoritmy MeSH
• anizotropie MeSH
• bílá hmota * diagnostické zobrazování   MeSH
• mozek diagnostické zobrazování   MeSH
• zobrazování difuzních tenzorů MeSH
• Publikační typ
• časopisecké články MeSH

We investigated the mass concentration, mineral composition and morphology of particles resuspended by children during scheduled physical education in urban, suburban and rural elementary school gyms in Prague (Czech Republic). Cascade impactors were deployed to sample the particulate matter. Two fractions of coarse particulate matter (PM(10-2.5) and PM(2.5-1.0)) were characterized by gravimetry, energy dispersive X-ray spectrometry and scanning electron microscopy. Two indicators of human activity, the number of exercising children and the number of physical education hours, were also recorded. Lower mass concentrations of coarse particulate matter were recorded outdoors (average PM(10-2.5) 4.1-7.4 μg m(-3) and PM(2.5-1.0) 2.0-3.3 μg m(-3)) than indoors (average PM(10-2.5) 13.6-26.7 μg m(-3) and PM(2.5-1.0) 3.7-7.4 μg m(-3)). The indoor concentrations of coarse aerosol were elevated during days with scheduled physical education with an average indoor-outdoor (I/O) ratio of 2.5-16.3 for the PM(10-2.5) and 1.4-4.8 for the PM(2.5-1.0) values. Under extreme conditions, the I/O ratios reached 180 (PM(10-2.5)) and 19.1 (PM(2.5-1.0)). The multiple regression analysis based on the number of students and outdoor coarse PM as independent variables showed that the main predictor of the indoor coarse PM concentrations is the number of students in the gym. The effect of outdoor coarse PM was weak and inconsistent. The regression models for the three schools explained 60-70% of the particular dataset variability. X-ray spectrometry revealed 6 main groups of minerals contributing to resuspended indoor dust. The most abundant particles were those of crustal origin composed of Si, Al, O and Ca. Scanning electron microscopy showed that, in addition to numerous inorganic particles, various types of fibers and particularly skin scales make up the main part of the resuspended dust in the gyms. In conclusion, school gyms were found to be indoor microenvironments with high concentrations of coarse particulate matter, which can contribute to increased short-term inhalation exposure of exercising children.

• MeSH
• dítě MeSH
• gymnastika MeSH
• inhalační expozice statistika a číselné údaje   MeSH
• látky znečišťující vzduch analýza   chemie   MeSH
• lidé MeSH
• monitorování životního prostředí MeSH
• pevné částice analýza   chemie   MeSH
• školy statistika a číselné údaje   MeSH
• velikost částic MeSH
• znečištění vzduchu ve vnitřním prostředí statistika a číselné údaje   MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH

Polycyclic aromatic hydrocarbons (PAHs) associated with particulate matter (PM) may induce oxidative damage via reactive oxygen species (ROS) generation. However, the kinetics of ROS production and the link with antioxidant response induction has not been well studied. To elucidate the differences in oxidative potential of individual PAH compounds and extractable organic matter (EOM) from PM containing various PAH mixtures, we studied ROS formation and antioxidant response [total antioxidant capacity (TAC) and expression of HMOX1 and TXNRD1] in human alveolar basal epithelial cells (A549 cells) and human embryonic lung fibroblasts (HEL12469 cells). We treated the cells with three concentrations of model PAHs (benzo[a]pyrene, B[a]P; 3-nitrobenzanthrone, 3-NBA) and EOM from PM <2.5 μm (PM2.5). ROS levels were evaluated at 8 time intervals (30 min-24 h). In both cell lines, B[a]P treatment was associated with a time-dependent decrease of ROS levels. This trend was more pronounced in HEL12469 cells and was accompanied by increased TAC. A similar response was observed upon 3-NBA treatment in HEL12469 cells. In A549 cells, however, this compound significantly increased superoxide levels. This response was accompanied by the decrease of TAC as well as HMOX1 and TXNRD1 expression. In both cell lines, a short-time exposure to EOMs tended to increase ROS levels, while a marked decrease was observed after longer treatment periods. This was accompanied by the induction of HMOX1 and TXNRD1 expression in HEL12469 cells and increased TAC in A549 cells. In summary, our data indicate that in the studied cell lines B[a]P and EOMs caused a time-dependent decrease of intracellular ROS levels, probably due to the activation of the antioxidant response. This response was not detected in A549 cells following 3-NBA treatment, which acted as a strong superoxide inducer. Pro-oxidant properties of EOMs are limited to short-time exposure periods.

• MeSH
• buňky A549 MeSH
• fibroblasty účinky léků   metabolismus   patologie   MeSH
• kinetika MeSH
• kultivované buňky MeSH
• lidé MeSH
• organické látky škodlivé účinky   MeSH
• pevné částice škodlivé účinky   MeSH
• plíce účinky léků   metabolismus   patologie   MeSH
• polycyklické aromatické uhlovodíky škodlivé účinky   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• náklady na zdravotní péči MeSH
• podpora zdraví MeSH
• poskytování zdravotní péče ekonomika   organizace a řízení   MeSH
• výdaje na zdravotnictví ekonomika   organizace a řízení   MeSH
• zdravotnické zdroje ekonomika   organizace a řízení   MeSH

The identification of prognostic markers in early multiple sclerosis (MS) is challenging and requires reliable measures that robustly predict future disease trajectories. Ideally, such measures should make inferences at the individual level to inform clinical decisions. This study investigated the prognostic value of longitudinal structural networks to predict 5-year Expanded Disability Status Scale (EDSS) progression in patients with relapsing-remitting MS (RRMS). We hypothesized that network measures, derived from MRI, outperform conventional MRI measurements at identifying patients at risk of developing disability progression. This longitudinal, multicentre study within the Magnetic Resonance Imaging in MS (MAGNIMS) network included 406 patients with RRMS (mean age = 35.7 ± 9.1 years) followed up for 5 years (mean follow-up = 5.0 ± 0.6 years). EDSS was determined to track disability accumulation. A group of 153 healthy subjects (mean age = 35.0 ± 10.1 years) with longitudinal MRI served as controls. All subjects underwent MRI at baseline and again 1 year after baseline. Grey matter atrophy over 1 year and white matter lesion load were determined. A single-subject brain network was reconstructed from T1-weighted scans based on grey matter atrophy measures derived from a statistical parameter mapping-based segmentation pipeline. Key topological measures, including network degree, global efficiency and transitivity, were calculated at single-subject level to quantify network properties related to EDSS progression. Areas under receiver operator characteristic (ROC) curves were constructed for grey matter atrophy and white matter lesion load, and the network measures and comparisons between ROC curves were conducted. The applied network analyses differentiated patients with RRMS who experience EDSS progression over 5 years through lower values for network degree [H(2) = 30.0, P < 0.001] and global efficiency [H(2) = 31.3, P < 0.001] from healthy controls but also from patients without progression. For transitivity, the comparisons showed no difference between the groups [H(2) = 1.5, P = 0.474]. Most notably, changes in network degree and global efficiency were detected independent of disease activity in the first year. The described network reorganization in patients experiencing EDSS progression was evident in the absence of grey matter atrophy. Network degree and global efficiency measurements demonstrated superiority of network measures in the ROC analyses over grey matter atrophy and white matter lesion load in predicting EDSS worsening (all P-values < 0.05). Our findings provide evidence that grey matter network reorganization over 1 year discloses relevant information about subsequent clinical worsening in RRMS. Early grey matter restructuring towards lower network efficiency predicts disability accumulation and outperforms conventional MRI predictors.

• MeSH
• atrofie patologie   MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• magnetická rezonanční tomografie metody   MeSH
• mladý dospělý MeSH
• mozek diagnostické zobrazování   patologie   MeSH
• prognóza MeSH
• progrese nemoci MeSH
• relabující-remitující roztroušená skleróza * diagnostické zobrazování   patologie   MeSH
• roztroušená skleróza * diagnostické zobrazování   patologie   MeSH
• šedá hmota diagnostické zobrazování   patologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH
• práce podpořená grantem MeSH

The main aim of this study was to compare the genotoxic potential of organic extracts from urban air particles collected in three different sampling periods in the center of Prague (Czech Republic). For this purpose, we analyzed the DNA adduct forming activity of extractable organic matter (EOM) from urban air particles <10 microm (PM10) in the human hepatoma cell line HepG2. DNA adducts were analyzed by (32)P-postlabelling with nuclease P1 enrichment. PM10 concentrations were 36.9 microg/m(3), 62.6mug/m(3) and 39.0 microg/m(3), in summer 2000, winter 2001 and winter 2005, respectively. The corresponding EOM contents were 5.0 microg/m(3) (13.9% of PM10), 14.9 microg/m(3) (23.8%) and 6.7 microg/m(3) (17.2%). The total DNA adduct levels induced by 10 microg EOM/ml were 4.7, 19.5 and 37.2 adducts/10(8) nucleotides in summer 2000, winter 2001 and winter 2005, respectively. However, when the EOM quantities per cubic meter of air were taken into consideration, the summer sample exhibited a 10-fold lower genotoxicity than did those of winter, while the difference between the winter samples was not significant: 23.4 in summer 2000, 291 in winter 2001 and 249 in winter 2005 (in relative units). Although the PM10 concentration in air and the EOM content in particles in winter 2005 were significantly lower than in winter 2001, the genotoxic potential of the ambient air in these samples was almost equal. There were significant positive correlations between the B[a]P and c-PAH content in EOM from various sampling periods and the total DNA adduct levels detected in the EOM-treated samples. These findings support the hypothesis that the B[a]P and c-PAH content in EOM is the most important factor that determines its genotoxic potential. Thus, estimating the genotoxic potential of the ambient air and predicting health risk should be based mainly on the c-PAH concentration and the biological activity of the extracts, while the mass of particles and the EOM content do not seem to be crucial determinants of ambient air genotoxicity.

• MeSH
• adukty DNA metabolismus   účinky léků   MeSH
• chromatografie na tenké vrstvě MeSH
• financování organizované MeSH
• izotopy fosforu MeSH
• látky znečišťující vzduch analýza   chemie   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• pevné částice analýza   farmakologie   MeSH
• polycyklické aromatické uhlovodíky analýza   farmakologie   MeSH
• roční období MeSH
• velkoměsta MeSH
• Check Tag
• lidé MeSH
• Geografické názvy
• velkoměsta MeSH

Ambient air pollution, namely exposure to air particulate matter (PM), has been shown to be connected with a number of adverse health effects. At least part of the effects can be caused by organic pollutant mixtures associated with PM, which can elicit a wide range of specific toxic potentials. These potentials could be affected by seasonal variation of pollutant mixtures and PM size fraction. To examine this, six size subfractions of PM10 were collected at rural and urban site in the Czech Republic in a year-long sampling campaign. The samples were assessed for aryl hydrocarbon (AhR)-mediated activity, estrogenicity and anti-androgenicity using mammalian cell models. The concentrations of detected toxic potentials differed among seasons. The greatest levels were observed in samples collected during winter when AhR-mediated effects and estrogenicity were at least 10-times greater than in summer. While the observed potentials were mostly less pronounced in samples from rural area, during winter, their AhR-mediated activity was twice as great as at the urban site. This was probably caused by the low-quality of fuel used for heating at the rural site. Assessed toxic potentials were associated mainly with PM size fractions with lesser aerodynamic diameters (<1 μm). Toxic potentials were compared with data from chemical analyses covering 102 chemicals from different pollutant groups to model their contribution to the observed effects. For AhR-mediated activity, chemical analyses explained on average 44% of the effect and the main identified effect-drivers were polycyclic aromatic hydrocarbons. For estrogenicity and anti-androgenicity, detected chemicals were able to explain on average less than 1.6% and 11% of the potentials, with their highest explicability reaching 13% and 57%, respectively. This was affected by the lack of data on specific toxic potency of some detected air pollutants, but also indicates a possible role of further not analyzed chemicals in these effects.

• MeSH
• látky znečišťující vzduch analýza   MeSH
• monitorování životního prostředí MeSH
• pevné částice analýza   MeSH
• roční období MeSH
• znečištění ovzduší * MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH

In this study, samples of soil and particulate matter obtained from the highly industrialized region of Ostrava, Czech Republic, are used for the toxicity evaluation of the selected metal(loid)s (Cd, Cr, Cu, Ni, Pb, Zn, As). We investigated the samples from sites supposedly affected the most by the local pollution sources using mineralogical techniques (XRD, SEM/EDS) to understand the solid speciation of the contaminants as the crucial factor affecting their release. Although the bulk composition was defined by common silicates and oxides that are rather resistant to leaching, the presence of tiny Ni, Pb, and/or Zn sulfate-like droplets indicated a potential increase of the solubility of these metals. In vitro tests simulating gastric and lung fluids were used to assess the exposure risk for humans, as well as metal(loid) bioaccessibility. Based on the results, the potential risk for the observed age group (3-year-old children) could be recognized, particularly in the cases of As, Pb and Cd for both oral and inhalation exposure. Arsenic exhibits high bioaccessibility (7.13-79.7%, with the median values of 10.6 and 15.6 for SGL and SLF, respectively), high daily intake (1.4- to 8.5-fold higher than the tolerable daily intake) and high concentrations in atmospheric PM10 (2.5 times the tolerable concentration in air). In contrast, Ni exceeded tolerable concentrations in the atmosphere up to 20-fold, but its bioaccessibility remained relatively low (0.1-22%), and Ni did not pose a major threat to human health. Cadmium, Pb and As originating from industrial activities and domestic heating have been suggested to be the most important pollutants (tolerable daily intake was exceeded by up to 74-, 34- and 8-fold for Cd, Pb and As, respectively).

• MeSH
• hodnocení rizik MeSH
• kovy MeSH
• látky znečišťující půdu * MeSH
• lidé MeSH
• monitorování životního prostředí metody   MeSH
• pevné částice MeSH
• předškolní dítě MeSH
• půda MeSH
• těžké kovy * MeSH
• vystavení vlivu životního prostředí statistika a číselné údaje   MeSH
• Check Tag
• lidé MeSH
• předškolní dítě MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH

Objectives: To investigate spatial patterns of gray matter (GM) atrophy and their association with disability progression in patients with early relapsing-remitting multiple sclerosis (MS) in a longitudinal setting. Methods: Brain MRI and clinical neurological assessments were obtained in 152 MS patients at baseline and after 10 years of follow-up. Patients were classified into those with confirmed disability progression (CDP) (n = 85) and those without CDP (n = 67) at the end of the study. An optimized, longitudinal source-based morphometry (SBM) pipeline, which utilizes independent component analysis, was used to identify eight spatial patterns of common GM volume co-variation in a data-driven manner. GM volume at baseline and rates of change were compared between patients with CDP and those without CDP. Results: The identified patterns generally included structurally or functionally related GM regions. No significant differences were detected at baseline GM volume between the sub-groups. Over the follow-up, patients with CDP experienced a significantly greater rate of GM atrophy within two of the eight patterns, after correction for multiple comparisons (corrected p-values of 0.001 and 0.007). The patterns of GM atrophy associated with the development of CDP included areas involved in motor functioning and cognitive domains such as learning and memory. Conclusion: SBM analysis offers a novel way to study the temporal evolution of regional GM atrophy. Over 10 years of follow-up, disability progression in MS is related to GM atrophy in areas associated with motor and cognitive functioning.

• MeSH
• atrofie MeSH
• lidé středního věku MeSH
• lidé MeSH
• longitudinální studie MeSH
• magnetická rezonanční tomografie MeSH
• mapování mozku MeSH
• mozek diagnostické zobrazování   patologie   MeSH
• progrese nemoci * MeSH
• relabující-remitující roztroušená skleróza diagnostické zobrazování   patologie   MeSH
• šedá hmota diagnostické zobrazování   patologie   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Patologie z okruhu poruch migrace neuronů, včetně heterotopic šedé hmoty mozkové, , jsou obecně považovány za vysoce epileptogenní. Vztahy mezi takovou stmikturální lézí a vlastní epileptogenní zónou však zůstávají nejednoznačné. V rámci přípravy chimirgické terapie epilepsie byla provedena video-stereo-EEG studie u pacienta s nodulární heterotopií, khnicky se manifestující gelastickými záchvaty. Výsledek vyšetření potvrdil primární roh strukturáhií leze v organizaci iktální aktivity a podpořil tak současnou představu o vysoké epileptické aktivitě ektopických neuronů. Při hodnocení iktální EEG aktivity v různých anatomických strukturách byla prokázána role gyrus cinguli anterior pro motorickou komponentu smíchu.

Pathological phenomena associated with neuronal migration disorders, incl. heterotopic grey matter are considered highly epileptogenic. Relations between such a structural lesion and the epileptogenic zone proper, however, remain equivocal. Within the framework of preparations for the surgical management of epilepsy a video-stereo-EEG study was made in a patient with heterotopic grey matter, suffering from gelastic seizures. The results of the examination confirmed the primary role of the structural lesion in the organization of ictal activity and supported also the contemporary idea on strong epileptic activity of ectopic neurones. When evaluating the ictal electric activity fi-om several anatomic structures the role of the gyrus cinguli anterior for the epileptic symptom of laughter was proved.

• MeSH
• audiovizuální záznam MeSH
• cingulární gyrus MeSH
• dítě MeSH
• elektroencefalografie metody   MeSH
• epilepsie diagnóza   etiologie   chirurgie   MeSH
• lidé MeSH
• mladiství MeSH
• neurony fyziologie   MeSH
• smích MeSH
• záchvaty etiologie   MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• Publikační typ
• kazuistiky MeSH