Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0220723 (PCA)
 4,687 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Single trial event-related cerebral potentials (ERPs) in response to skin stimuli of various intensities and qualities in man were investigated in respect to their nociceptive information content. Electrical constant current stimuli (20 msec, 2 - 8 mA) and mechanical force controlled stimuli (20 msec, 0.8 - 3.2 N) were applied to the tip of the left middle finger. Four intensities of each stimulus quality were given, each intensity appearing 40 times in standardized randomized order. EEG segments (between 5 sec before and 500 msec after stimulus onset) were subjected to computer analysis. ERP wave form was shown to depend upon the amount of alpha waves in the prestimulus EEG. For analysis, only subjects with low power in the alpha band were selected. Principal component analysis was applied to all single trial ERPs measured using the variance-covariance matrix of association. Six principal components (PCs) were extracted accounting for about 90% of total variance. Five of the extracted PCs had well located loading maxima: PC1 (50 - 80 msec), PC4 (140 - 160 msec), PC3 (200 - 250 msec), PC4 (280 - 360 msec), PC5 (400 - 500 msec); PC6 appeared polyphasic. Analysis of variance of the mean PC scores revealed that one PC (PC1) discriminated between quality, and 4 PCs (PC1 - PC4) between quantity of stimulation. Eliminating effects of stimulus intensity resulted in two PCs (PC2, PC4) which distinguished exclusively between non-pain and pain. PCA applied to disjunctive subsets of ERPs, corresponding to the different experimental conditions, yielded practically identical sets of PCs, such that no specific ERP component emerged when pain was reported.
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PMID:Principal component analysis of pain-related cerebral potentials to mechanical and electrical stimulation in man. 617 4

MKT-077, a delocalized lipophilic cation, selectively targets cancer cells. MKT-077 has been reported to inhibit the growth of several tumor types and has undergone phase I clinical testing. We have examined the effect of MKT-077, alone and in combination with the antidiarrheal drug loperamide. Ten human cancer cell lines, four prostate (PC3, DU145, LNCaP, MDA-PCA-2B), two breast (MCF-7 and MDA-MB-231) and four colon (LoVo, Colo320DM, SW1116 and LS174t) were tested in vitro. Cells were grown to confluency prior to treatment. Loperamide potentiated the antiproliferative effect of MKT-077 in all ten cell lines, in a dose-dependent manner. The sensitivity of MDA-PCA-2B cells, the two breast and four colon cancer cell lines to MKT-077 was relatively low (>2.5 microg/ml MKT-077 required to inhibit growth by 95%). In these cell lines, 0.5-5 microg/ml (1-10 microM) loperamide caused a marked increase in the response to MKT-077. Loperamide is known to activate micro-opioid receptors at nanomolar concentrations and block voltage-gated calcium channels at micromolar doses. We found that calcium channel-blockers diltiazem and nifedipine (10-20 microg/ml), as well as tamoxifen (1.5-2.5 microg/ml) can also potentiate the growth-inhibitory effects of MKT-077. These synergistic interactions could be exploited for therapeutic benefit.
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PMID:Potentiation of the antiproliferative activity of MKT-077 by loperamide, diltiazem and tamoxifen. 1453 37

Principal component analysis was applied to XRD data from a series of Mg(OH)2 samples prepared under different hydrothermal conditions from bischofite (MgCl2.6H2O) and carnallite (KCl.MgCl2.6H2O), owing to differences in full width at half-maximum (fwhm) as well as in the intensity ratio I001/I101 of the respective diffraction peaks. According to the PCA results, the four principal components are able to explain 93% of the total variance and the samples can be classified into four main groups. For instance, the principal component PC1 can be interpreted as the crystallite size along the 101 direction since it is related to the fwhm of this peak. On the other hand, PC3 is related to orientation effects along 001 and 101 directions as it is dominated by the relative intensities of the two peaks. Finally, a comparison of the scanning electron microscopy images of the samples classified in each group revealed that in most of the cases a distinct morphology predominates within each group, which can be explained on the basis of the brucite growth mechanism.
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PMID:Principal component analysis of X-ray diffraction patterns to yield morphological classification of brucite particles. 1732 3

Fingerprinting analysis of fresh ginseng according to root age was performed using 1H-NMR spectroscopy and multivariate analysis techniques. Various peaks were detected in the aliphatic (0-3 ppm), sugar (3-6 ppm), and aromatic (6-9 ppm) regions of the 1H-NMR spectra of the water extracts of fresh ginseng root. The use of principal components (PCs) analysis (PCA) for metabolomic profiling allowed the large 1H-NMR data set obtained for various metabolites to be reduced to PC1, PC2, and PC3. Two dimensional score plots showed clear separations with these three components at different roots ages, and explained 89.6% of the total variance. Canonical discriminant analysis identified the ginseng roots at various ages from the NMR results with over 89.9% discrimination accuracy. These results indicate that the combination of 1H-NMR and PCA provides a very promising tool for the authentication and quality control of fresh ginseng roots at different ages.
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PMID:Fingerprinting analysis of fresh ginseng roots of different ages using 1H-NMR spectroscopy and principal components analysis. 1825 51

Concomitant with the rapid global urbanization process, land use change detection has been the focus and "hot spot" of global change research all the time. In the present study, the rigorous orthorectification was first applied to the SPOT-5 data to guarantee precise geometric correction and image registration. Afterwards, a methodology integrating PCA-enhancement and multi-source classifier was adopted to detect the land use changes in urban area. The results show that the first three PCs derived from multi-temporal-PCA contain most of the spectral information among which unchanged land use is highlighted in PC1 and PC2, and changed land use is mainly enhanced in PC3. The following multi-source classifier integrating unsupervised classifier (ISODATA) and supervised classifier (Maximum Likelihood) accurately extracts all the information. The findings from accuracy assessment demonstrate that the overall accuracy for the proposed method reaches 92.58, KAPPA coefficient is 0.92, and proving figures are also produced for the user's and producer's accuracies. It was further found that the proposed method yielded better accuracy than that of traditional post-classification comparison approach.
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PMID:[Detecting land use change using PCA-enhancement and multi-source classifier from SPOT images]. 1981 May 46

Successive projections algorithm (SPA) was employed to select the optimal combination of principal components (PCs) which were obtained by principal component analysis. Short-wave near infrared spectra of milk powder was firstly analyzed by PCA, and the optimal combination of obtained first eight PCs was determined by SPA. The optimal PC combination of fat content prediction was PC1 , PC2, PC 4, PC5, PC6 and PC7, and the combination for protein content prediction was PC1, PC2, PC3, PC4, PC5 and PC8. Least-squares support vector machine models inputted by different PC combination were established to predict fat and protein content, respectively. Both the fat and protein content prediction results of the PC combination selected by SPA were better than those of first four PCs to first eight PCs. Rp2, and root mean square errors for prediction and residual predictive deviation of prediction results of the PC combination selected by SPA were 0.989, 0.1703 and 9.5343, respectively for fat, and 0.9876, 0.1348 and 8.9274 for protein. The overall results demonstrate that SPA can fast and effectively select the optimal PC combination. The selecting process is simple and does not need abundant parameter debugging.
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PMID:[Study on combinatorial optimization of spectral principal components using successive projections algorithm]. 2003 49

Body size is an important determinant of the diving and foraging ability in air-breathing marine vertebrate predators. Satellite-linked dive recorders were used during 2003-2004 to investigate the foraging behavior of 22 male California sea lions (Zalophus californianus, a large, sexually dimorphic otariid) and to evaluate the extent to which body size explained variation among individuals and foraging strategies. Multivariate analyses were used to reduce the number of behavioral variables used to characterize foraging strategies (principal component analysis, PCA), to identify individually based foraging strategies in multidimensional space (hierarchical cluster analysis), and to classify each individual into a cluster or foraging strategy (discriminant analysis). Approximately 81.1% of the variation in diving behavior among individuals was explained by three factors: diving patterns (PC1), foraging effort (PC2), and behavior at the surface (PC3). Individuals were classified into three distinct groups based on their diving behavior (shallow, mixed depth, and deeper divers), and jackknife resampling of the data resulted in correct group assignment 86% of the time. Body size as an independent variable was positively related to dive duration and time spent ashore and negatively related to time at sea, and it was a key parameter in PC2 used to classify the three distinct clusters. Differences among individual-based foraging strategies probably were driven by differences in body size, which enabled larger animals to dive deeper and forage more efficiently by targeting different and perhaps larger prey items. The occurrence of foraging specializations within a species and age class has implications for quantitative modeling of population-level predator-prey interactions and ecosystem structure.
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PMID:The role of body size in individual-based foraging strategies of a top marine predator. 2046 15

By using a 2-DE based workflow, the proteome of wild and potassium transport mutant trk1,2 under optimal growth potassium concentration (50mM) has been analyzed. At the exponential and stationary phases, both strains showed similar growth, morphology potassium content, and Vmax of rubidium transport, the only difference found being the Km values for this potassium analogue transport, higher for the mutant (20mM) than for the wild (3-6mM) cells. Proteins were buffer-extracted, precipitated, solubilized, quantified, and subjected to 2-DE analysis in the 5-8 pH range. More differences in protein content (37-64mgg(-1) cell dry weight) and number of resolved spots (178-307) were found between growth phases than between strains. In all, 164 spots showed no differences between samples and a total of 105 were considered to be differential after ANOVA test. 171 proteins, corresponding to 71 unique gene products have been identified, this set being dominated by cytosolic species and glycolitic enzymes. The ranking of the more abundant spots revealed no differences between samples and indicated fermentative metabolism, and active cell wall biosynthesis, redox homeostasis, biosynthesis of amino acids, coenzymes, nucleotides, and RNA, and protein turnover, apart from cell division and growth. PCA analysis allowed the separation of growth phases (PC1 and 2) and strains at the stationary phase (PC3 and 4), but not at the exponential one. These results are also supported by clustering analysis. As a general tendency, a number of spots newly appeared at the stationary phase in wild type, and to a lesser extent, in the mutant. These up-accumulated spots corresponded to glycolitic enzymes, indicating a more active glucose catabolism, accompanied by an accumulation of methylglyoxal detoxification, and redox-homeostasis enzymes. Also, more extensive proteolysis was observed at the stationary phase with this resulting in an accumulation of low Mr protein species.
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PMID:2-DE based proteomic analysis of Saccharomyces cerevisiae wild and K+ transport-affected mutant (trk1,2) strains at the growth exponential and stationary phases. 2063 88

Wild female Crassostrea corteziensis oyster (n=245) were analyzed over one year to understand the main ecophysiological events associated to gonad development. Different indicators (mainly biochemical) were analyzed to infer: i) utilization and accumulation of energy reserves (e.g. neutral lipids, carbohydrates, proteins; vitellogenin), ii) membrane components provided by the diet as essential nutrients and indicative of cell proliferation (e.g. highly unsaturated fatty acids linked to phospholipids, sterols), iii) indicators of food availability (chlorophyll a in water, pigments in tissues, specific fatty acids and sterols), iv) gonad development (e.g. gonad coverage area, vitellin). A PCA analysis was applied to 269 measured variables. The first PC (PC1) was composed of total carbohydrate and lipid concentration, percentage of esterified sterols, fatty acids specific of diatoms; 16:1n-7/16:0, 20:5n-3 in neutral lipids with positive loadings and non methylene-interrupted fatty acids (NMI) in neutral lipids with negative loadings. The second PC (PC2) was composed of 18:4n-3 in lipid reserves and the concentration of zeaxanthin, a pigment typical of cyanobacteria with positive loadings and the proportion of 20:4n-6 in polar lipids with negative loading. The third PC (PC3) was composed of gonad coverage area (GCA) and the concentration of vitellin. Variation in GCA confirms that gonad development began in April with an extended period of spawning and rematuration from April to November. The PCA further shows that a second period of minimal maturation from November to March corresponds to the accumulation of reserves (PC1) together with an initial high availability of food (PC2) at the beginning of this period. These two periods are in accordance with the classical periods of allocation of energy to reserves followed by gonad development reported for several mollusks.
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PMID:Seasonal variations of biochemical, pigment, fatty acid, and sterol compositions in female Crassostrea corteziensis oysters in relation to the reproductive cycle. 2261 18

Prostate cancer is a clinically heterogeneous disease, ranging from indolent asymptomatic disease to very aggressive metastatic and life threatening forms of the disease. Distant metastasis represents the major lethal cause of prostate cancer. The most critical clinical challenge in the management of the patients is identifying those individuals at risk of developing metastatic disease. To understand the molecular mechanisms of prostate cancer metastasis and identify markers with metastatic potential, we have analyzed protein expression in two syngeneic prostate cancer cells lines PC3-N2 and PC3-ML2 using isobaric tags for relative and absolute quantitation labeling and multi-dimensional protein identification technology liquid chromatography matrix assisted laser desorption ionization tandem mass spectrometry. PC3-N2 is lowly metastatic while PC3-ML2 highly metastatic. A total of 1,756 proteins were identified in the analyses with 130 proteins showing different expression levels (p<0.01) in the two cell lines. Out of these, 68 proteins were found to be significantly up-regulated while 62 are significantly down-regulated in PC3-ML2 cells compared with PC3-N2 cells. The upregulation of plectin and vimentin which were the most significantly differentially expressed were validated by Western blot and their functional relevance with respect to invasion and migration was determined by siRNA gene silencing. To our knowledge, this study is the first to demonstrate that up-regulation of vimentin and plectin expression positively correlates with the invasion and metastasis of androgen-independent PCA.
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PMID:Variable metastatic potentials correlate with differential plectin and vimentin expression in syngeneic androgen independent prostate cancer cells. 2371 85


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