Random Forest is an ensemble of decision trees based on the bagging and random subspace concepts. As suggested by Breiman, the strength of unstable learners and the diversity among them are the ensemble models' core strength. In this paper, we propose two approaches known as oblique and rotation double random forests. In the first approach, we propose rotation based double random forest. In rotation based double random forests, transformation or rotation of the feature space is generated at each node. At each node different random feature subspace is chosen for evaluation, hence the transformation at each node is different. Different transformations result in better diversity among the base learners and hence, better generalization performance. With the double random forest as base learner, the data at each node is transformed via two different transformations namely, principal component analysis and linear discriminant analysis. In the second approach, we propose oblique double random forest. Decision trees in random forest and double random forest are univariate, and this results in the generation of axis parallel split which fails to capture the geometric structure of the data. Also, the standard random forest may not grow sufficiently large decision trees resulting in suboptimal performance. To capture the geometric properties and to grow the decision trees of sufficient depth, we propose oblique double random forest. The oblique double random forest models are multivariate decision trees. At each non-leaf node, multisurface proximal support vector machine generates the optimal plane for better generalization performance. Also, different regularization techniques (Tikhonov regularization, axis-parallel split regularization, Null space regularization) are employed for tackling the small sample size problems in the decision trees of oblique double random forest. The proposed ensembles of decision trees produce trees with bigger size compared to the standard ensembles of decision trees as bagging is used at each non-leaf node which results in improved performance. The evaluation of the baseline models and the proposed oblique and rotation double random forest models is performed on benchmark 121 UCI datasets and real-world fisheries datasets. Both statistical analysis and the experimental results demonstrate the efficacy of the proposed oblique and rotation double random forest models compared to the baseline models on the benchmark datasets.

• MeSH
• algoritmy * MeSH
• analýza hlavních komponent MeSH
• rotace MeSH
• support vector machine * MeSH
• Publikační typ
• časopisecké články MeSH

The degree of response to subthalamic nucleus deep brain stimulation (STN-DBS) is individual and hardly predictable. We hypothesized that DBS-related changes in cortical network organization are related to the clinical effect. Network analysis based on graph theory was used to evaluate the high-density electroencephalography (HDEEG) recorded during a visual three-stimuli paradigm in 32 Parkinson's disease (PD) patients treated by STN-DBS in stimulation "off" and "on" states. Preprocessed scalp data were reconstructed into the source space and correlated to the behavioral parameters. In the majority of patients (n = 26), STN-DBS did not lead to changes in global network organization in large-scale brain networks. In a subgroup of suboptimal responders (n = 6), identified according to reaction times (RT) and clinical parameters (lower Unified Parkinson's Disease Rating Scale [UPDRS] score improvement after DBS and worse performance in memory tests), decreased global connectivity in the 1-8 Hz frequency range and regional node strength in frontal areas were detected. The important role of the supplementary motor area for the optimal DBS response was demonstrated by the increased node strength and eigenvector centrality in good responders. This response was missing in the suboptimal responders. Cortical topologic architecture is modified by the response to STN-DBS leading to a dysfunction of the large-scale networks in suboptimal responders.

• MeSH
• elektroencefalografie MeSH
• hluboká mozková stimulace * MeSH
• hodnocení výsledků zdravotní péče MeSH
• lidé středního věku MeSH
• lidé MeSH
• mozková kůra patofyziologie   MeSH
• nervová síť patofyziologie   MeSH
• nucleus subthalamicus patofyziologie   MeSH
• Parkinsonova nemoc patofyziologie   terapie   MeSH
• psychomotorický výkon fyziologie   MeSH
• senioři MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

OBJECTIVES: The aim was to describe the contribution of basal ganglia (BG) thalamo-cortical circuitry to the whole-brain functional connectivity in focal epilepsies. METHODS: Interictal resting-state fMRI recordings were acquired in 46 persons with focal epilepsies. Of these 46, 22 had temporal lobe epilepsy: 9 left temporal (LTLE), 13 right temporal (RTLE); 15 had frontal lobe epilepsy (FLE); and 9 had parietal/occipital lobe epilepsy (POLE). There were 20 healthy controls. The complete weighted network was analyzed based on correlation matrices of 90 and 194 regions. The network topology was quantified on a global and regional level by measures based on graph theory, and connection-level changes were analyzed by the partial least square method. RESULTS: In all patient groups except RTLE, the shift of the functional network topology away from random was observed (normalized clustering coefficient and characteristic path length were higher in patient groups than in controls). Links contributing to this change were found in the cortico-subcortical connections. Weak connections (low correlations) consistently contributed to this modification of the network. The importance of regions changed: decreases in the subcortical areas and both decreases and increases in the cortical areas were observed in node strength, clustering coefficient and eigenvector centrality in patient groups when compared to controls. Node strength decreases of the basal ganglia, i.e. the putamen, caudate, and pallidum, were displayed in LTLE, FLE, and POLE. The connectivity within the basal ganglia-thalamus circuitry was not disturbed; the disturbance concerned the connectivity between the circuitry and the cortex. SIGNIFICANCE: Focal epilepsies affect large-scale brain networks beyond the epileptogenic zones. Cortico-subcortical functional connectivity disturbance was displayed in LTLE, FLE, and POLE. Significant changes in the resting-state functional connectivity between cortical and subcortical structures suggest an important role of the BG and thalamus in focal epilepsies.

• MeSH
• bazální ganglia diagnostické zobrazování   patofyziologie   MeSH
• dospělí MeSH
• elektroencefalografie MeSH
• epilepsie parciální diagnostické zobrazování   patofyziologie   MeSH
• kyslík krev   MeSH
• lidé středního věku MeSH
• lidé MeSH
• magnetická rezonanční tomografie MeSH
• mapování mozku * MeSH
• mladý dospělý MeSH
• mozková kůra diagnostické zobrazování   MeSH
• nervová síť diagnostické zobrazování   MeSH
• nervové dráhy diagnostické zobrazování   patofyziologie   MeSH
• počítačové zpracování obrazu MeSH
• senioři MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

AIM: To create a predictive score for the discrimination between benign and malignant parotid tumors using elastographic parameters and to compare its sensitivity and specificity with standard ultrasound. METHODS: A total of 124 patients with parotid gland lesions for whom surgery was planned were examined using conventional ultrasound, Doppler examination, and shear wave elastography. Results of the examinations were compared with those ones of histology. RESULTS: There were 96 benign and 28 malignant lesions in our cohort. Blurred tumor margin alone proved to be an excellent predictor of malignancy with the sensitivity of 79% and specificity of 97%. Enlarged cervical lymph nodes, tumor vascularisation, microcalcifications presence, homogeneous echogenicity, and bilateral occurrence also discriminated between benign and malignant tumors. However, their inclusion in a predictive model did not improve its performance. Elastographic parameters (the stiffness maxima and minima ratio being the best) also exhibited significant differences between benign and malignant tumors, but again, their inclusion did not significantly improve the predictive power of the blurred margin classifier. CONCLUSION: Even though elastography satisfactorily distinguishes benign from malignant lesions on its own, it hardly provides any additional value in evaluation of biological character of parotid gland tumors when used as an adjunct to regular ultrasound examination.

• MeSH
• diferenciální diagnóza * MeSH
• dospělí MeSH
• elastografie metody   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• nádory příušní žlázy diagnóza   diagnostické zobrazování   patologie   MeSH
• parotis diagnostické zobrazování   patologie   MeSH
• pevnost ve smyku MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ultrasonografie metody   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Bud outgrowth is controlled by environmental and endogenous factors. Through the use of the photosynthesis inhibitor norflurazon and of masking experiments, evidence is given here that light acts mainly as a morphogenic signal in the triggering of bud outgrowth and that initial steps in the light signaling pathway involve cytokinins (CKs). Indeed, in rose (Rosa hybrida), inhibition of bud outgrowth by darkness is suppressed solely by the application of CKs. In contrast, application of sugars has a limited effect. Exposure of plants to white light (WL) induces a rapid (after 3-6 h of WL exposure) up-regulation of CK synthesis (RhIPT3 and RhIPT5), of CK activation (RhLOG8), and of CK putative transporter RhPUP5 genes and to the repression of the CK degradation RhCKX1 gene in the node. This leads to the accumulation of CKs in the node within 6 h and in the bud at 24 h and to the triggering of bud outgrowth. Molecular analysis of genes involved in major mechanisms of bud outgrowth (strigolactone signaling [RwMAX2], metabolism and transport of auxin [RhPIN1, RhYUC1, and RhTAR1], regulation of sugar sink strength [RhVI, RhSUSY, RhSUC2, and RhSWEET10], and cell division and expansion [RhEXP and RhPCNA]) reveal that, when supplied in darkness, CKs up-regulate their expression as rapidly and as intensely as WL Additionally, up-regulation of CKs by WL promotes xylem flux toward the bud, as evidenced by Methylene Blue accumulation in the bud after CK treatment in the dark. Altogether, these results suggest that CKs are initial components of the light signaling pathway that controls the initiation of bud outgrowth.

• MeSH
• biologické modely MeSH
• časové faktory MeSH
• cytokininy metabolismus   farmakologie   MeSH
• meristém genetika   růst a vývoj   metabolismus   MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• regulace genové exprese u rostlin účinky léků   účinky záření   MeSH
• regulátory růstu rostlin metabolismus   farmakologie   MeSH
• Rosa genetika   růst a vývoj   metabolismus   MeSH
• rostlinné proteiny genetika   metabolismus   MeSH
• signální transdukce účinky léků   genetika   účinky záření   MeSH
• světlo * MeSH
• tma MeSH
• výhonky rostlin genetika   růst a vývoj   metabolismus   MeSH
• vývojová regulace genové exprese účinky léků   účinky záření   MeSH
• xylém genetika   růst a vývoj   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH

Sleep manifests itself by the spontaneous emergence of characteristic oscillatory rhythms, which often time-lock and are implicated in memory formation. Here, we analyze a neural mass model of the thalamocortical loop in which the cortical node can generate slow oscillations (approximately 1 Hz) while its thalamic component can generate fast sleep spindles of σ-band activity (12-15 Hz). We study the dynamics for different coupling strengths between the thalamic and cortical nodes, for different conductance values of the thalamic node's potassium leak and hyperpolarization-activated cation-nonselective currents, and for different parameter regimes of the cortical node. The latter are listed as follows: (1) a low activity (DOWN) state with noise-induced, transient excursions into a high activity (UP) state, (2) an adaptation induced slow oscillation limit cycle with alternating UP and DOWN states, and (3) a high activity (UP) state with noise-induced, transient excursions into the low activity (DOWN) state. During UP states, thalamic spindling is abolished or reduced. During DOWN states, the thalamic node generates sleep spindles, which in turn can cause DOWN to UP transitions in the cortical node. Consequently, this leads to spindle-induced UP state transitions in parameter regime (1), thalamic spindles induced in some but not all DOWN states in regime (2), and thalamic spindles following UP to DOWN transitions in regime (3). The spindle-induced σ-band activity in the cortical node, however, is typically the strongest during the UP state, which follows a DOWN state "window of opportunity" for spindling. When the cortical node is parametrized in regime (3), the model well explains the interactions between slow oscillations and sleep spindles observed experimentally during Non-Rapid Eye Movement sleep. The model is computationally efficient and can be integrated into large-scale modeling frameworks to study spatial aspects like sleep wave propagation.

• Publikační typ
• časopisecké články MeSH

BACKGROUND: Cognitive impairment in Parkinson's disease (PD) is associated with altered connectivity of the resting state networks (RSNs). Longitudinal studies in well cognitively characterized PD subgroups are missing. OBJECTIVES: To assess changes of the whole-brain connectivity and between-network connectivity (BNC) of large-scale functional networks related to cognition in well characterized PD patients using a longitudinal study design and various analytical methods. METHODS: We explored the whole-brain connectivity and BNC of the frontoparietal control network (FPCN) and the default mode, dorsal attention, and visual networks in PD with normal cognition (PD-NC, n = 17) and mild cognitive impairment (PD-MCI, n = 22) as compared to 51 healthy controls (HC). We applied regions of interest-based, partial least squares, and graph theory based network analyses. The differences among groups were analyzed at baseline and at the one-year follow-up visit (37 HC, 23 PD all). RESULTS: The BNC of the FPCN and other RSNs was reduced, and the whole-brain analysis revealed increased characteristic path length and decreased average node strength, clustering coefficient, and global efficiency in PD-NC compared to HC. Values of all measures in PD-MCI were between that of HC and PD-NC. After one year, the BNC was further increased in the PD-all group; no changes were detected in HC. No cognitive domain z-scores deteriorated in either group. CONCLUSION: As compared to HC, PD-NC patients display a less efficient transfer of information globally and reduced BNC of the visual and frontoparietal control network. The BNC increases with time and MCI status, reflecting compensatory efforts.

• MeSH
• dospělí MeSH
• kognitivní dysfunkce etiologie   patologie   psychologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• longitudinální studie MeSH
• magnetická rezonanční tomografie MeSH
• mozek diagnostické zobrazování   patologie   MeSH
• nervová síť diagnostické zobrazování   patologie   MeSH
• neurozobrazování MeSH
• Parkinsonova nemoc komplikace   patologie   psychologie   MeSH
• prefrontální mozková kůra patologie   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• studie případů a kontrol MeSH
• temenní lalok patologie   MeSH
• testy pro posouzení mentálních funkcí a demence MeSH
• zrakové korové centrum patologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

POEMS syndrom je onemocnění s multiorgánovým postižením, které zahrnuje v případě úplné manifestace přítomnost polyneuropatie, organomegalie, endokrinopatie, monoklonální gamapatie a kožních změn, sdružené většinou s přítomností osteosklerotického typu plazmocytomu. V předlo- ženém sdělení je podán rozbor průběhu tohoto onemocnění u 70letého muže s přítomností neoby- čejně závažné senzomotorické neuropatie dolních končetin, u něhož došlo postupně k rozvoji úpl- ného obrazu POEMS syndromu včetně hyperpigmentace s hypertrichózou, mnohočetných angiomů kůže i oboustranné axilární lymfadenomegalie. V laboratorním obraze byla zaznamenána v souladu s obvyklým obrazem polyglobulie, trombocytóza i přítomnost M-proteinu typu IgG-lambda v séru. Při EMG vyšetření byl zjištěn obraz závažné neuropatie s postižením axonu i myelinu, v lymfatické uzlině projevy angiofolikulární hyperplazie Castelmannova typu. V kostní dřeni byla lehká plazmo- cytóza klonálního charakteru (IgG-L) s projevy částečné dřeňové fibrózy a zvýšené osteoblastické proliferace. Radiografie skeletu odhalila ložiska osteosklerózy v proximálních úsecích diafýzy humerů, ale normální obraz při vyšetření skeletu pomocí scintigrafie a DEXA. Byly zaznamenány zvýšené hodnoty FSH, prolaktinu, C-peptidu, ukazatelů kostního obratu (telopeptidu, osteokalcinu a pyridinolinu), sérových hladin cytoadhezivní molekuly VCAM-1, IL-2 a nízké hodnoty testostero- nu. Po léčbě melfalanem s kortikosteroidy, následné aktinoterapii osteosklerotických lézí i axilár- ních lymfatických uzlin s intenzivní rehabilitací, došlo k výraznému zlepšení stavu s úplnou úpra- vou svalové síly a mobility a k úpravě ukazatelů hemogramu, hodnot S-B2M, prolaktinu, PICP, došlo k určitému poklesu hodnot M-proteinu a k úpravě počtu plazmocytů v kostní dřeni. Z předloženého sdělení vyplývá, že u všech nejasných polyneuropatií středního věku s průkazem M-proteinu je nutno pátrat po přítomnosti osteosklerotických lézí, resp. po přítomnosti syndromu POEMS, jako východiska intenzivní, široce pojaté léčby.

The POEMS syndrome is a disease with a multiorgan affection, which involves in case of full manifestation the presence of polyneuropathy, organomegaly, endocrinopathy, monoclonal gamma- pathy and dermal changes, associated in the majority with the presence of the osteosclerotic type of plasmacytoma. In the submitted paper the authors present an analysis of the course of the disease in a 70-year-old man who suffered from unusually severe sensomotor neuropathy of the lower extremities and who eventually developed the complete picture of POEMS syndrome, incl. hyper- pigmentation with hypertrichosis, multiple skin angiomas and bilateral axillary lymphadenomega- ly. Laboratory tests revealed, consistent with the usual picture, polyglobulia, thrombocytosis and the presence of M-protein type IgG-lambda in serum. EMG examination revealed serious neuropathy with affection of the axon and myelin, the lymph node manifestations of angiofollicular hyperplasia of Castelmann’s type. In the bone marrow slight plasmacytosis of clonal character (IgG-L) with manifestations of partial medullary fibrosis and increased osteoblastic proliferation was found. Radiography of the skeleton revealed foci of osteosclerosis in the proximal sections of the diaphysis of the humerus but a normal appearance on examination of the skeleton by scintigraphy and DEXA. Raised values of FSH, prolactin, C-peptide, indicators of bone turnover (telopeptide, osteocalcin and pyridinoline), serum levels of the cytoadhesive VCAM-1 molecule, IL-2 and low testosterone levels were found. After treatment with melfalan with corticoids, subsequent actinotherapy of osteoscle- rotic lesions and axillary lymph nodes with intensive rehabilitation marked improvement of the condition occurred with complete restoration of muscler strength and mobility and normalization of indicators of the haemogram, S-B2M values, prolactin, PICP, a certain decline of values of M-protein occurred and normalization of the number of plasmocytes in bone marrow. From the submitted paper ensues that in all obscure polyneuropathies in middle age with the presence of M-protein it is important to search for osteosclerotic lesions, the presence of POEMS syndrome as the baseline of intensive broadly conceived treatment.

• MeSH
• dospělí MeSH
• lidé MeSH
• melfalan terapeutické užití   MeSH
• osteoskleróza diagnóza   etiologie   MeSH
• plazmocytom diagnóza   komplikace   terapie   MeSH
• POEMS syndrom diagnóza   komplikace   terapie   MeSH
• prednison terapeutické užití   MeSH
• radioterapie MeSH
• senioři MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• Publikační typ
• kazuistiky MeSH

• MeSH
• nádory mortalita   MeSH
• Publikační typ
• sborníky MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• hematologie a transfuzní lékařství
• onkologie

• MeSH
• alergologie a imunologie MeSH
• autoimunitní nemoci MeSH
• imunita MeSH
• nemoci imunitního systému MeSH
• transplantační imunologie MeSH
• Publikační typ
• monografie MeSH
• příručky MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• alergologie a imunologie