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Modular organization of finger movements by the human central nervous system.

The motor system may generate automated movements, such as walking, by combining modular spinal motor synergies. However, it remains unknown whether a modular neuronal architecture is sufficient to generate the unique flexibility of human finger movements, which rely on cortical structures. Here we show that finger movements evoked by transcranial magnetic stimulation (TMS) of the primary motor cortex reproduced distinctive features of the spatial representation of voluntary movements as identified in previous neuroimaging studies, consistent with naturalistic activation of neuronal elements. Principal component analysis revealed that the dimensionality of TMS-evoked movements was low. Principal components extracted from TMS-induced finger movements resembled those derived from end-postures of voluntary movements performed to grasp imagined objects, and a small subset of them was sufficient to reconstruct these movements with remarkable fidelity. The motor system may coordinate even the most dexterous movements by using a modular architecture involving cortical components.

Adult↗

Genome-wide linkage scan for the metabolic syndrome in the HERITAGE Family Study.

The metabolic syndrome involves multiple and interactive effects of genes and environmental factors. To identify chromosomal regions encoding genes possibly predisposing to the metabolic syndrome, we performed a genome-wide scan with 456 white and 217 black participants from 204 nuclear families of the HERITAGE Family Study, using regression-based, single- and multipoint linkage analyses on 509 markers. A principal component analysis was performed on 7 metabolic syndrome-related phenotypes. Two principal components, PC1 and PC2 (55% of the variance), were used as metabolic syndrome phenotypes. ANOVA was used to quantify the familial aggregation of PC1 and PC2. Family membership contributed significantly (P < 0.0023) to the variance in PC1 (r(2) = 0.38 in whites; r(2) = 0.55 in blacks) and PC2 (r(2) = 0.51; r(2) = 0.48). In whites, promising evidence for linkage (P < 0.0023) was found for PC1 (2 markers on 10p11.2) and PC2 (a marker on 19q13.4). Suggestive evidence of linkage (0.01 > P > 0.0023) appeared for PC1 (1q41 and 9p13.1) and PC2 (2p22.3). In blacks, promising linkage was found for PC2 on 1p34.1, and suggestive linkage was found on 7q31.3 and 9q21.1. The genome-wide scan revealed evidence for quantitative trait loci on chromosomal regions that have been previously linked with individual cardiovascular disease and type 2 diabetes risk factors. Some of these chromosomal regions harbor promising potential candidate genes.

Adolescent↗

[Relationship of occupational injuries with social and economic factors].

OBJECTIVE: To explore the relationship of occupational injuries with social and economic factors in chemical industry during 2000.01 - 2001.12. METHOD: 1:2 paired case-control study, univariable logistic regression analysis, principal component analysis, and multiple logistic regression analysis were used in this study. RESULTS: Univariable analysis showed that occupational injuries had significant relationship with age, sex, education, employment pattern, technology, workplace, work changing, wage, family income, enterprise scale, enterprise proprietorship, projective device, operation rules, and training rules of work safety. The extracted four principal components (PC(1), PC(2), PC(3) and PC(4), ranked by contribution) gave good expressions to the initial 11 variables. The cumulative proportion of the four principal components reached 77.36%. PC(1) was the indicative factor of occupational injuries, which represented 46.69% information of initial variables. PC(2) was the kinetic factor of occupational injuries. PC(3) was the stable factor of occupational injuries. PC(4) was the sex factor of occupational injuries. The results of multiple conditional logistic regression analysis showed that occupational injuries had statistically significant relationship with PC(1) and PC(2). Among the initial variables, sex, employment pattern, income, scale of enterprise, and property of enterprise were more prominent. CONCLUSION: Occupational injuries are related with multiple social and economic factors, which often interact on each other. The prevention and control of occupational injuries should require a comprehensive approach, including training and education of work safety, improving workers' consciousness of self-protection, and enhancing proprietors' consciousness of work safety.

Accidents, Occupational↗

Phenotypic composition of salivary gland tumors: an application of principal [corrected] component analysis to tissue microarray data.

The tissue organization of the salivary gland is complex, and a large number of salivary gland tumor entities with a broad morphologic spectrum are listed, creating tumor classification schema for the salivary glands that are difficult to understand. In the present study, we attempted to examine how the anatomical components of the salivary gland are associated with morphological subtypes of tumors. We selected a panel of 12 molecules, which labeled one or some of the components, with all of the markers covering every component of the salivary glands. Using tissue microarray, expression profiles of these molecules were examined in four representative spots from each of 88 salivary gland tumors. The resulting large data matrix was analyzed using principle component analysis (PCA). We considered the first three eigenvectors to be significant; as the eigenvalues were more than 1.0 and the cumulative proportion achieved was 67%. Comparison with expression patterns in normal tissue suggested that the three components represented myoepithelial differentiation, and luminal and basal cell phenotypes. Then, we compared the PCA results with individual morphologic subtypes. Individual subtypes were clustered among the three dimensions of the components. This implies that salivary gland tumors may be well characterized by using only three components.

14-3-3 Proteins↗

[East European gene pool and diseases in the rural population of European Russia].

New data on the association of the state of health and the disease incidence with the gene pool were obtained in the East European population. The second principal component (PC2.G, 11.4% of the total variance) of the geographic variation in the gene pool (100 alleles of 34 loci) showed a distinct latitudinal dependence corresponding to the natural zonality of Eastern Europe. This was also characteristic of the first principal component (PC1.M, 75.6% of the total variance) of the geographic variation in the disease incidence (i.e., the number of all new cases diagnosed in out-patient clinics per year) in the rural population. The disease incidence decreased from the south-southeast to the north-northwest in European Russia. The coefficient of the geographic pairwise correlation between PC2.G and PC1.M was r = 0.945; their specific correlation remained high (r = 0.864), even after a correction for the effects of age composition and heterozygosity. Thus, an insignificant variation in the gene pool was shown to significantly affect the geographic distribution of disease incidence in the East European population of Russia (eta 2 = 0.892). A correlation of mapped geographic distributions of PC1.M and PC2.G in the modern population with those of the principal components of the geographic variation of the late Paleolithic material culture in Eastern Europe was analyzed. The origin of the latitudinal zonality of the modern gene pool was dated back to the late Pleistocene-early Holocene. A conclusion was made that diseases that affected reproduction and lethality in the Paleolithic population still represent a mechanism of the gene pool's adaptation to the natural zonality of the environment. The latitudinal zonality of disease incidence, which was characteristic of the ancient population, is conserved in the today's population, owing to the gene pool.

Adolescent↗

A new approach to the study of protein-protein interaction by FTIR: complex formation between cytochrome P450BM-3 heme domain and FMN reductase domain.

We describe a new approach to the study of protein-protein interaction using Fourier transform infrared spectroscopy (FTIR). This approach is based on the combination of FTIR technique with both protein titration experiments and the principal component analysis (factor analysis) of the IR absorption spectra in the 1500-1800 cm(-1) region for the protein mixtures. We have applied this approach to the interaction of the heme domain with the FMN domain of bacterial monooxygenase cytochrome P450BM-3 (CYP102A1). The analysis reveals that the first principal component reflects the protein-protein complex formation because the loading factors show a clear systematic dependence on the concentration of the heme domain according to a titration curve with a dissociation constant of approximately 5 microM. The spectrum of the first principal component has been assigned to structural changes in the secondary structure (increase of beta-sheet and alpha-helix and decrease of turn structures), amino acid side chains (protonation of aspartate and C-terminal COO group), and deprotonation of a propionic acid COOD group in the heme.

Bacillus megaterium↗

[A case-control study on risk factors for nosocomial infection by extended-spectrum beta-lactamases-producing bacteria].

OBJECTIVE: To explore the risk factors for nosocomial infection caused by extended-spectrum beta-lactamases (ESBLs)-producing bacteria in hospitals of Zhejiang province. METHODS: One hundred and eighty-five cases with nosocomial infection (108 men and 77 women, with an average age of 55 +/- 17 years) caused by positive-ESBLs bacteria, including 59 cases of respiratory infection, 71 with urinary infection, ten with blood infection, 30 with wound infection and 59 with other infection, and 77 controls with nosocomial infection (54 men and 23 women, with an average age of 54 +/- 20 years) caused by negative-ESBLs bacteria, including 38 cases of respiratory infection, 20 with urinary infection, six with blood infection, eight with wound infection and five with other infection, from six hospitals in Zhejiang Province were studied during May 1999 to May 2000. Data were analyzed with unconditional logistic regression and principal component analysis (PCA). RESULTS: Multivariate unconditional logistic regression analysis showed that the independent risk factors for nosocomial infection were use of the third generation cephalosporins for more than three days (odds ratio, OR 4.52, 95% confidence interval of OR 2.30 - 8.89), combined use of antibiotics (OR 2.86, 95% CI 1.51 - 5.43), use of quinolones for more than three days (OR 2.44, 95% CI 1.18 - 5.04), use of adrenal cortical hormone (OR 2.16, 95% CI 1.08 - 4.31) and oxygen inhalation (OR 2.56, 95% CI 1.14 - 5.72). Five principal components were extracted from the 14 risk factors for nosocomial infection with ESBLs-producing bacteria by principal component analysis, with a contribution of cumulative variance of 60.2%, and arranged in an order as follows, use of ventilator, tracheal intubation or tracheotomy, oxygen inhalation, retaining needle in vein, indwelling urethral catheter, use of the third generation cephalosporins over three days, hospitalization over ten days, use of quinolones over three days, combined use of antibiotics, use of aminoglycosides antibiotic over a week, use of adrenal cortical hormone, catheterized examination and prophylactic use of antibiotics. CONCLUSIONS: Nosocomial infection with ESBLs-producing bacteria could attribute to multiple factors, mainly to invasive manipulation and use of antibiotics.

Case-Control Studies↗

Infrared spectral models demonstrate that exposure to environmental chemicals leads to new forms of DNA.

Environmental chemicals are known to induce a high degree of hydroxyl radical-mediated damage in DNA. Accordingly, we tested the hypothesis that this exposure leads to new forms of DNA using principal components analysis of Fourier transform infrared spectra. The hepatic DNA of English sole (controls) from an essentially clean environment was compared with that of sole inhabiting a chemically contaminated environment. All livers studied were cancer-free; however, a high incidence of liver cancer has been found in the exposed population. The exposed sole were sampled twice, 2 years apart, while the sediments in which they live were under remediation. After obtaining infrared spectra, the first three principal components (PC1, PC2, and PC3) were calculated and found to represent 97% of the total spectral variance. When the principal component scores were plotted in 3-dimensional space, clusters of points were obtained that represented the DNA from the control and exposed groups. Each of the points was derived from approximately 10(6) wavenumber-absorbance correlations. The spatial location of a point was a highly discriminating measure of DNA structure. The clusters of points were completely separated, demonstrating that the three groups could be 100% correctly classified. The points from the control group were tightly clustered whereas those from the exposed groups were highly diverse. The findings demonstrate that exposure to environmental chemicals results in new, structurally diverse forms of DNA that likely play an important role in carcinogenesis.

Animals↗

Cell responsiveness in macaque superior temporal polysensory area measured by temporal discriminants.

The firing-rate data from 341 cells from two macaques' superion temporal polysensory area (STPa) were subjected to three different analyses to determine the temporal firing-rate patterns in response to visual optic flow patterns. The data were collected while the monkey viewed four types of optic flow and responded to the change in the display. The mean firing rate (MFR) analysis considered the mean change in firing rate for 500 ms after stimulus onset; the discriminant (DIS) analysis and the principal components (PCA+DIS) analysis considered the change in time-binned firing rate over 1000 ms after stimulus presentation, using bin sizes of 30 to 500 ms. The DIS analysis used a step-down discriminant analysis to find temporal windows in which the cell's firing rate could discriminate among the stimuli; the PCA+DIS analysis extracted the principal components of the cell's firing rates without regard for the stimulus type and then applied a step-down discriminant analysis to the PCA scores to determine whether any of the principal components could discriminate among the stimuli. The two temporal analyses found cells sensitive to the optic flows that the MFR analysis missed. A small proportion of cells showed multiple selectivities under the temporal analyses. Thus, the temporal analyses give a more complete representation of the information encoded by the firing properties of STPa neurons. Finally, this approach incorporates temporal approaches with classical statistical techniques in order to select tuned neurons from a population in an unbiased manner.

Action Potentials↗

Quantitative analysis of finger motion coordination in hand manipulative and gestic acts.

This article reports an experimental study that aimed to quantitatively analyze motion coordination patterns across digits 2-5 (index to little finger), and examine the kinematic synergies during manipulative and gestic acts. Twenty-eight subjects (14 males and 14 females) performed two types of tasks, both right-handed: (1) cylinder-grasping that involved concurrent voluntary flexion of digits 2-5, and (2) voluntary flexion of individual fingers from digit 2 to 5 (i.e., one at a time). A five-camera opto-electronic motion capture system measured trajectories of 21 miniature reflective markers strategically placed on the dorsal surface landmarks of the hand. Joint angular profiles for 12 involved flexion-extension degrees of freedom (DOF's) were derived from the measured coordinates of surface markers. Principal components analysis (PCA) was used to examine the temporal covariation between joint angles. A mathematical modeling procedure, based on hyperbolic tangent functions, characterized the sigmoidal shaped angular profiles with four kinematically meaningful parameters. The PCA results showed that for all the movement trials (n = 280), two principal components accounted for at least 98% of the variance. The angular profiles (n = 2464) were accurately characterized, with the mean (+/-SD) coefficient of determination (R2) and root-mean-square-error (RMSE) being 0.95 (+/-0.12) and 1.03 degrees (+/-0.82 degrees ), respectively. The resulting parameters which quantified both the spatial and temporal aspects of angular profiles revealed stereotypical patterns including a predominant (87% of all trials) proximal-to-distal flexion sequence and characteristic interdependence--involuntary joint flexion induced by the voluntarily flexed joint. The principal components' weights and the kinematic parameters also exhibited qualitatively similar variation patterns. Motor control interpretations and new insights regarding the underlying synergistic mechanisms, particularly in relation to previous findings on force synergies, are discussed.

Biomechanical Phenomena↗

Do different dimensions of the metabolic syndrome change together over time? Evidence supporting obesity as the central feature.

OBJECTIVE: The metabolic syndrome is a loosely defined cluster of cardiovascular risk factors including low HDL cholesterol, hypertriglyceridemia, glucose intolerance, and hypertension. Evidence for inclusion of these features in the syndrome has mostly come from cross-sectional studies, and a few studies have examined how the various factors change together over time. RESEARCH DESIGN AND METHODS: We conducted a prospective population-based cohort study of 937 individuals aged 40-65 years who underwent oral glucose tolerance testing on two occasions at 4.5-year intervals. Changes in the components of the metabolic syndrome were analyzed by principal component analysis in the entire population and in a subgroup of 471 individuals who did not receive pharmaceutical therapy for hypertension and dyslipidemia. RESULTS: Principal component analysis identified three independent factors in men: a blood pressure factor (systolic and diastolic blood pressure and BMI), a glucose factor (fasting and 120-min postload glucose, BMI, waist-to-hip ratio [WHR], and fasting insulin level), and a lipid factor (triglycerides and HDL cholesterol, BMI, WHR, and fasting insulin level). In women, an additional factor was identified, which included BMI, WHR, fasting insulin, and triglycerides. Analysis of the contribution of these variables to the different subdimensions indicated that BMI was the central feature of the syndrome in both sexes. CONCLUSIONS: This analysis of change in the features of the metabolic syndrome over time provides evidence of the fundamental importance of obesity in the origin of this disorder.

Adult↗

Neural network classification of infrared spectra of control and Alzheimer's diseased tissue.

Artificial neural network classification methods were applied to infrared spectra of histopathologically confirmed Alzheimer's diseased and control brain tissue. Principal component analysis was used as a preprocessing technique for some of these artificial neural networks while others were trained using the original spectra. The leave-one-out method was used for cross-validation and linear discriminant analysis was used as a performance benchmark. In the cases where principal components were used, the artificial neural networks consistently outperformed their linear discriminant counterparts; 100% versus 98% correct classifications, respectively, for the two class problem, and 90% versus 81% for a more complex five class problem. Using the original spectra, only one of the three selected artificial neural network architectures (a variation of the back-propagation algorithm using fuzzy encoding) produced results comparable to the best corresponding principal component cases: 98% and 85% correct classifications for the two and five class problems, respectively.

Alzheimer Disease↗

Testing for candidate gene linkage disequilibrium using a dense array of single nucleotide polymorphisms in case-parents studies.

The future of genetic studies of complex human diseases will rely more and more on the epidemiologic association paradigm, in particular the use of the transmission/disequilibrium test to detect linkage disequilibrium in a case-parents study. With the rapid progress in genomic studies, many single nucleotide polymorphisms will be identified and genotyped within a very short physical distance. Analyzing multiple single nucleotide polymorphisms within a candidate gene/region with Bonferroni correction for multiple transmission/disequilibrium tests will lead to a conservative test, and hence a power loss. I propose a new method, the "Adaptive PRIncipal COmponent Test" (APRICOT). The method has the following properties: (1) it does not need haplotype information; (2) it is nonparametric-it does not make specific assumptions about the population history or population structure; and (3) the calculation of the test statistic and the determination of its significance level are simple and straightforward. Monte-Carlo simulation reveals that adaptive principal component test maintains the nominal significance level under the null hypothesis of no linkage disequilibrium, even under complex situations of multiple ancestral haplotypes and structured populations. It provides a substantial power advantage over the conventional Bonferroni approach. The adaptive principal component test is a promising method for candidate gene testing using single nucleotide polymorphisms.

Genetic Markers↗

Fatty acid profiling of soybean cotyledons by near-infrared spectroscopy.

Genetically improved soybean grain often contains altered fatty acid profiles. Such alterations can have deleterious effects on seed germination and seedling development, making it necessary to monitor fatty acid profiles in follow-up physiological studies. The objective of this research was to quantify the five fatty acids in soybean (Glycine max) cotyledons using near-infrared (NIR) spectroscopy. Soybean cotyledon samples were dried, ground, and scanned with visible and NIR radiation from 400 to 2500 nm, and reflectance was recorded. Samples were also analyzed by gas chromatography (GC) for palmitic, stearic, oleic, linoleic, and linolenic acids and total oil; GC data, expressed as actual concentration and proportion of total oil, were regressed against spectral data to develop calibration equations. Equation statistics indicated that four of the five fatty acids could be predicted accurately by NIR spectroscopy; the fifth fatty acid could be determined by subtraction. Principal component analysis revealed that most of the spectral variation in this population was due to chlorophyll absorbance in the visible region. Therefore, the spectra were trimmed to include the NIR region only (1100-2500 nm), and a second set of equations was developed. Equations based exclusively on NIR spectra had equal or greater precision than equations based on visible and NIR spectra. Principal component analysis and partial least squares analysis revealed that even after trimming, at least 90% of the spectral variation was unrelated to fatty acid, though variation from fatty acid was identified in the second and third principal components. This research provides an NIR method for complete fatty acid profiling of soybean cotyledons. Equations were achieved with NIR spectra only, so spectrophotometers that analyze both the visible and NIR regions are not needed for this analysis. In addition, equations were possible with a 250 mg sample, which is one-tenth the normal sample size for this analysis.

Cotyledon↗

Genetic structure of the human population in the Po delta.

The genetic structure of the population of Ferrara Province in the Po delta in Italy was investigated using chi 2 analysis, kinship analysis, analysis of correspondences, and geographical mapping of principal components of gene frequencies. chi 2 Analysis tests for Hardy-Weinberg equilibrium and for heterogeneity of gene and phenotype frequencies; kinship analysis tests for association between indicators of genetic and geographic proximity; analysis of correspondences relates localities and genetic systems in an eigenvectorial space; and geographic mapping displays the principal components of gene frequencies in the real space. In 1,364 adults in 26 residential units, seven presumably neutral isoenzyme systems were typed; ACP1 ESD, GLO I, GPT, PGD, PGM1 and PGP. It was found that average kinship for these neutral systems is correlated with geographic distance in this small area, but not as strongly as kinship for beta-thalassemia. A north-south gradient was observed for ESD. Analysis of correspondences indicated GPT, PGM1, and GLO I as the systems contributing most to differentiation within the province. The maps obtained from principal components of gene frequencies were consistent with the migrational history of the area.

Adult↗

Delusions in individuals with schizophrenia: factor structure, clinical correlates, and putative neurobiology.

BACKGROUND: Delusions are a central feature of schizophrenia, yet our understanding of their neurobiology is limited. Attempt to link dimensions of psychopathology to putative neurobiological mechanisms depends on careful delineation of symptoms. Previous factor analytic studies of delusions in schizophrenia were limited by several methodological problems, including the use of patients medicated with antipsychotics, inclusion of nondelusion symptoms in the analyses, and/or inclusion of patients with psychotic disorders other than schizophrenia. These problems may have possibly biased the resulting factor structure and contributed to the inconclusive findings regarding the neurobiology of positive symptoms. Our goal is to examine the factor structure of delusions in antipsychotic-free individuals with diagnoses of schizophrenia/schizoaffective disorder. SAMPLING AND METHODS: We assessed 83 antipsychotic-free individuals with DSM-IV diagnoses of schizophrenia/schizoaffective disorder. A principal component analysis was conducted on the delusions symptoms of the SAPS. RESULTS: The principal component analysis resulted in three distinct and interpretable factors explaining 58.3% of the variance. The Delusions of Influence factor was comprised by delusions of being controlled, thought withdrawal, thought broadcasting, thought insertion, and mind reading. The Self-Significance Delusions factor was comprised by delusions of grandeur, reference, religious, and delusions of guilt/sin. The Delusions of Persecution factor was comprised solely by persecutory delusions. The three factors displayed distinct associations with hallucinations, bizarre behavior, attention, positive formal thought disorder, and avolition/apathy. CONCLUSIONS: The results indicate that delusions are best described by three distinct subtypes. The authors propose a novel model linking the three delusion subtypes, attributions to self/other, and putative neurobiological mechanisms. Implications for future research are discussed, as well as links to cognitive-behavioral conceptualizations of delusions.

Adolescent↗

Assessing heavy metal sources in agricultural soils of an European Mediterranean area by multivariate analysis.

According to the European Thematic Strategy for Soil Protection, the characterization of the content and source of heavy metals in soils are necessary to establish quality standards on a regional level that allow the detection of sampling sites affected by pollution. In relation to this, the surface horizons of 54 agricultural soils under vegetable crops in the Alicante province (Spain), a representative area of the European Mediterranean region, were sampled to determine the content of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn. Analytical determinations were performed by atomic absorption spectroscopy after microwave sample digestion in acid solution. Results indicated that heavy metal levels were similar to those reported by authors working on agricultural soils from other parts of the Mediterranean region, with the exception of Cu and Pb in some samples. Multivariate analysis (principal component analysis and cluster analysis) was performed to identify a common source for heavy metals. Moreover, soil properties were determined in order to characterize agricultural soils and to analyze relationships between heavy metal contents and soil properties. The content of Co, Cr, Fe, Mn, Ni and Zn were associated with parent rocks and corresponded to the first principal component called the lithogenic component. A significant correlation was found between lithogenic metals and some soil properties such as soil organic matter, clay content, and carbonates, indicating an important interaction among them. On the other hand, elements such as Cd, Cu and Pb were related to anthropic activities and comprised the second (Cu and Pb) and third principal components (Cd), designated the anthropogenic components. Generally, Cd, Cu and Pb showed a lower correlation with soil properties due to the fact that they remain in available forms in these agricultural soils. Taking into account these results and other achieved in other parts of the European Mediterranean region, it can be concluded that soil quality standards are highly needed to declare soils affected by human induced pollution. This is particularly relevant for anthropogenic metals (Cd, Cu and Pb, and in some areas also Zn). Further research in other agricultural areas of the region would improve the basis for proposing such soil quality standards.

Agriculture↗

The factorial reliability of the Middlesex Hospital Questionnaire in normal subjects.

The internal reliability of the Middlesex Hospital Questionnaire and its component subscales has been checked by means of principal components analyses of data on 256 normal subjects. The subscales (with the possible exception of Hysteria) were found to contribute to the general underlying factor of psychoneurosis. In general, the principal components analysis points to the reliability of the subscales, despite some item overlap.

Adolescent↗