Reflection of fetal heart electrical activity is present in registered abdominal ECG signals. However this signal component has noticeably less energy than concurrent signals, especially maternal ECG. Therefore traditionally recommended independent component analysis, fails to separate these two ECG signals. Multistage principal component analysis (PCA) is proposed for step-by-step extraction of abdominal ECG signal components. Truncated representation and subsequent subtraction of cardio cycles of maternal ECG are the first steps. The energy of fetal ECG component then becomes comparable or even exceeds energy of other components in the remaining signal. Second stage PCA concentrates energy of the sought signal in one principal component assuring its maximal amplitude regardless to the orientation of the fetus in multilead recordings. Third stage PCA is performed on signal excerpts representing detected fetal heart beats in aim to perform their truncated representation reconstructing their shape for further analysis. The algorithm was tested with PhysioNet Challenge 2013 signals and signals recorded in the Department of Obstetrics and Gynecology, Lithuanian University of Health Sciences. Results of our method in PhysioNet Challenge 2013 on open data set were: average score: 341.503 bpm(2) and 32.81 ms.
Although it is well documented that soluble beta amyloid (Aβ) oligomers are critical factors in the pathogenesis of Alzheimer's disease (AD) by causing synaptic dysfunction and neuronal death, the primary mechanisms by which Aβ oligomers trigger neurodegeneration are not entirely understood. We sought to investigate whether toxic small Aβ(1-42) oligomers induce changes in plasma membrane potential of cultured neurons and glial cells in rat cerebellar granule cell cultures leading to neuronal death and whether these effects are sensitive to the N-methyl-D-aspartate receptor (NMDA-R) antagonist MK801. We found that small Aβ(1-42) oligomers induced rapid, protracted membrane depolarization of both neurons and microglia, whereas there was no change in membrane potential of astrocytes. MK801 did not modulate Aβ-induced neuronal depolarization. In contrast, Aβ1(-42) oligomer-induced decrease in plasma membrane potential of microglia was prevented by MK801. Small Aβ(1-42) oligomers significantly elevated extracellular glutamate and caused neuronal necrosis, and both were prevented by MK801. Also, small Aβ(1-42) oligomers decreased resistance of isolated brain mitochondria to calcium-induced opening of mitochondrial permeability transition pore. In conclusion, the results suggest that the primary effect of toxic small Aβ oligomers on neurons is rapid, NMDA-R-independent plasma membrane depolarization, which leads to neuronal death. Aβ oligomers-induced depolarization of microglial cells is NMDA-R dependent.
Background The efficacy of histological analysis of colon sections used for evaluation of inflammation severity can be improved by means of digital imaging giving quantitative estimates of main diagnostic features. The aim of this study was to reveal most valuable diagnostic features reflecting inflammation severity in colon and elaborate the evaluation method for computer-aided diagnostics. Methods Tissue specimens from 24 BALB/c mice and 15 patients were included in the study. Chronic and acute colon inflammation in mice was induced by oral administration of dextran sulphate sodium (DSS) solution, while mice in the control group did not get DSS. Human samples of inflamed colon tissue were obtained from patients with ulcerative colitis ( n = 6). Non-inflamed colon tissue of control subjects ( n = 9) was obtained from patients with irritable bowel syndrome or functional obstipation. Analysis of morphological changes in mice and human colon mucosa was performed using 4-μm haematoxylin-eosin (HE) sections. The features reflecting morphological changes in the images of colon mucosa were calculated by convolution of Gabor filter bank and array of pixel values. All features were generalized by calculating mean, histogram skewness and entropy of every image response. Principal component analysis was used to construct optimal representation of morphological changes. Results First principal component (PC1) was representing the major part of features variation (97 % in mice and 71 % in human specimens) and was selected as a measure of inflammation severity. Validation of new measure was performed by means of custom-made software realizing double blind comparison of differences in PC1 with expert’s opinion about inflammation severity presented in two compared pictures. Overall accuracy of 80 % for mice and 67 % for human was reached. Conclusion Principal component analysis of spatial frequency features of histological images may provide continuous scale estimation of inflammation severity of colon tissue.
The aim of this study was the quantitative evaluation of gastrointestinal cancer cell motility and 5-aminolevulinic acid (5-ALA)-induced fluorescence in vitro using mathematical morphology and structural analysis methods. The results of our study showed that MKN28 cells derived from the lymph node have the highest motility compared with AGS or HCT116 cells derived from primary tumors. Regions of single cells were characterized as most moving, and “tightly packed” cell colonies as nearly immobile. We determined the reduction of cell motility in late passage compared to early passage. Application of 5-ALA caused fluorescence in all investigated cells, and the fluorescence was different with regard to the cell type and application time. We observed higher fluorescence in MKN28 cells. Comprehensive image analysis did not reveal any statistically significant difference in fluorescence intensity between “tightly packed” cell regions, where nearly no motility was registered and loosely distributed cells, where the highest cell motility was registered. In conclusions, our study revealed that MKN28 cells derived from the lymph node have higher motility and 5-ALA-induced fluorescence than AGS or HCT116 derived from primary tumors. Moreover, image analysis based on a large amount of processed data is an important tool to study these tumor cell properties.
SCARB1 rs5888 and environmental oxidative stress have a prominent role in ARMD susceptibility, early ARMD progression to advanced stage disease and even in the outcome of the disease-an area of macular lesion.
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