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At least 217 records · Page 12Linked to original sources

A generalized higher-order correlation analysis framework for multi-omics network inference.

Multiple -omics (genomics, proteomics, etc.) profiles are commonly generated to gain insight into a disease or physiological system. Constructing multi-omics networks with respect to the trait(s) of interest provides an opportunity to understand relationships between molecular features but integration is challenging due to multiple data sets with high dimensionality. One approach is to use canonical correlation to integrate one or two omics types and a single trait of interest. However, these types of methods may be limited due to (1) not accounting for higher-order correlations existing among features, (2) computational inefficiency when extending to more than two omics data when using a penalty term-based sparsity method, and (3) lack of flexibility for focusing on specific correlations (e.g., omics-to-phenotype correlation versus omics-to-omics correlations). In this work, we have developed a novel multi-omics network analysis pipeline called Sparse Generalized Tensor Canonical Correlation Analysis Network Inference (SGTCCA-Net) that can effectively overcome these limitations. We also introduce an implementation to improve the summarization of networks for downstream analyses. Simulation and real-data experiments demonstrate the effectiveness of our novel method for inferring omics networks and features of interest.

Genomics↗

Correlational analysis in comparative gerontology: an examination of some problems.

Correlation coefficients are widely used in comparative gerontology. However, due to many pitfalls, only a poor knowledge can be gained from these studies in many cases. For instance, a few variables gathered from few species may be used, with no attention to possible confounding variables giving spurious correlations. This article describes some of these problems and proposes to use more thoroughly multivariate analysis in comparative gerontology.

Aging↗

[Clinical feature of Rett syndrome and MeCP2 genotype/phenotype correlation analysis].

OBJECTIVE: Rett syndrome (RTT) is a neurodevelopmental disorder which causes severe mental retardation. This study aimed at elucidating clinical features of 66 Chinese RTT cases diagnosed by The Department of Pediatric Neurology, Peking University First Hospital since 1987, and at analysis of the MeCP2 genotype / phenotype correlation. METHODS: Sixty-six RTT cases were followed up every one to two years to get the information of their clinical manifestations and the response to the L-carnitine treatment which was administered to the patients at a dose of 80-100 mg/(kg d). MeCP2 mutation analysis by PCR and sequencing were performed on 39 cases. RESULTS: In this cohort of cases, the onset of the disease occurred between 3 and 38 months of age, 89% of the cases lost their purposeful hand use at 7 months to six years of age, all the cases had stereotype hand movement which presented at 1 to 5 years of age, 85% of the cases lost language ability at 11 months to eight years of age, 21% of the cases lost the ability of walking at ages of 2 years and 9 months to 15 years. The symptoms/signs such as small head circumference, seizures, breathing irregularities, teeth grinding, scoliosis/ kyphosis were presented in many of the cases. The clinical manifestations were improved in 6 cases after L-carnitine treatment. MeCP2 gene mutation was found in 64% of the cases. Two cases with non-sense mutation C502t (amino acid change R168X) died, two cases with missense mutation C397T (amino acid change R133C) and one case with missense mutation A398T (amino acid change R133H) preserved several words. CONCLUSION: Deceleration of the head growth, loss of acquired purposeful hand use, stereotype hand movement and language deterioration were the main characteristics of RTT. L-carnitine could improve the clinical manifestation of some cases. There are some correlations between MeCP2 genotype and phenotype.

Adolescent↗

A neuroforensic analysis of the wounds of President John F. Kennedy: Part 2--A study of the available evidence, eyewitness correlations, analysis, and conclusions.

A substantial body of literature exists surrounding the assassination and subsequent pathological examination of President John F. Kennedy. In the first part of this series, we provided a previously undocumented eyewitness account by a neurosurgeon of what transpired in Trauma Room 1 of Parkland Memorial Hospital on November 22, 1963. The current article reviews the copious literature and extensive controversy regarding President Kennedy's wounds. The autopsy report, ballistics data, official reviews of the autopsy data, and Dr. Grossman's observations are correlated in an effort to provide a neuroforensic analysis of the nature of the wounds that President Kennedy sustained. The final article of the series will relate the wounds to the timing of the shots and the location of the President as his limousine traversed Dealey Plaza and will discuss the sites from which the bullets could have been fired.

Autopsy↗

How long does DNA keep the memory of its conformation? A time-dependent canonical correlation analysis of molecular dynamics simulation.

The time dependence of the correlation between motions of different parts of DNA is analyzed from a 200 ps molecular dynamics simulation of the double-stranded self-complementary d(CTGATCAG) in the B form. Each nucleotide is decomposed into three subunits corresponding to the furanose ring (SU), the base (BA), and the backbone (SK). The motion of each subunit is considered as the superimposition of rigid body translation, rigid body rotation, and internal deformation. Canonical time-dependent correlation functions calculated with coordinates describing the different components of the subunits motion are defined and computed. This allows us to probe how long a particular type of motion of one subunit influences the other types of motions of other subunits (cross correlation functions) or how long a particular subunit keeps the memory of its own conformation or location (autocorrelation functions). From autocorrelation analysis it is found that deformation decorrelates within a few tenths of picoseconds, rotational correlation times are on the order of 8 ps, while translational motions are long-time correlated. The deformation of a subunit is not correlated to the deformation of another one (at the 200 ps time scale of our simulation), but influences slightly their translation and orientation as time increases.

Base Sequence↗

Dependence of in vitro-in vivo correlation analysis acceptability on model selections.

The objectives of this study were to assess the influence of pharmacokinetic and dissolution model selection on the success of in vitro-in vivo correlation (IVIVC) analysis of fast-, medium-, and slow-dissolving metoprolol tartrate immediate-release tablet formulations. Several different compartmental models were fit to the fast formulation plasma data. Three candidate models with the best fits were ranked 1, 2, and 3 and used to predict AUC and Cmax of the medium and slow formulations. Acceptability of each model to predict the medium and slow formulations was determined using +/- 20% as the limit for acceptable relative prediction error. When the best dissolution models were used, models 1 and 2 each failed to adequately predict Cmax for slow formulation (-26.8% error for model 1 and -20.4% error for model 2). However, the less appropriate model 3 adequately predicted Cmax for slow formulation (-15.1% error). The selection of the dissolution model also determined the outcome of IVIVC analysis, again with a less appropriate model resulting in successful prediction. When the Weibull function was used to characterize dissolution, model 2 failed to adequately predict Cmax for slow formulation (-20.4% error); however, model 2 adequately predicted Cmax for slow formulation when dissolution was characterized using the poorer fitting first-order model (-14.4% error). These results indicate that the success or failure of external validation of these metoprolol tartrate tablets was dependent on the pharmacokinetic and the dissolution models employed. Considering the role of subjectivity in identifying pharmacokinetic and dissolution models, these findings suggest a need to develop objective criteria to identify models a priori to IVIVC analysis.

Biological Availability↗

[Correlation analysis of lipids and apolipoproteins in plasma HDL, LDL and VLDL of normal subjects and endogenous hypertriglyceridemics].

The linear correlation and multiple stepwise regression analysis of lipids and apolipoproteins in plasma, HDL, LDL and VLDL of 20 normal subjects and 20 patients with endogenous hypertriglyceridemia was made. The result of simple factor analysis showed that there was a positive correlation of TG and VLDL TG with apoC II, C III, E, LDL apoB100 and VLDL apoC II, C III, E, B100; and a negative correlation with HDL apoA I. HDL-C was related positively with apoA I, HDL apoA I, C III and negatively with apoC III, E, LDL apoB100 and VLDL apoB100, C II, C III, E. TC was correlated positively with apoB100 and LDL apoB100. The result of multiple factor analysis showed that apoC III, E, B100/A I, VLDL apoC III and HDL apo C II, E, C II/C III, among 20 factors, were main factors which were related with TG. Apo C III, VLDL apoC III and LDL apoB100 were main factors which affected VLDL TG. ApoB100, and C II were main apolipoproteins which were related with TC; while the main apolipoproteins which affected HDL-C were apoA I, HDL apoA I, C II, VLDL apoE, HDL apoA II, the significance of the results is discussed.

Apolipoproteins↗

Regression and correlation analysis of preoperative versus intraoperative assessment of axes during navigated total knee arthroplasty.

OBJECTIVE: Modern computer assisted surgery (CAS) systems allow accurate positioning of the implants in navigated Total Knee Arthroplasty (TKA). However, when an operation is performed with a navigation system, it is important to know if the anatomical situation of the knee is reflected equally in both the preoperative image (e.g., CT) and the intraoperative navigation setup. In this study, we compared the preoperative anatomical situation to the virtual intraoperative situation of the navigation setup. MATERIAL AND METHODS: We analyzed 24 navigated operations. Intraoperatively, the condylar twist angle (CTA) was documented with the navigation system by measuring the angle between the transepicondylar axis (TEA) and posterior condyle axis (PCA). This data was compared with the preoperative data from the CT scan. RESULTS: Statistical analysis revealed that there was no correlation between the pre- and intraoperative data (r = 0.095). CONCLUSIONS: Statistically, there is no possibility of collecting the same angles and axes when using the two different methods (CT and navigation) on the same knee. It is not possible to copy the preoperative anatomical situation exactly with the virtual intraoperative data. Reasons for this include systematic errors, as well as inter- and intraobserver errors in both methods.

Arthroplasty, Replacement, Knee↗

Detection of clonal excess in lymphoproliferative disease by kappa/lambda analysis: correlation with immunoglobulin gene DNA rearrangement.

Previous studies have suggested that analysis of the distribution of surface immunoglobulin light chain isotypes by flow cytometry provides evidence for monoclonality of B cell tumors and may detect populations of circulating tumor cells in patients with lymphoproliferative disease. We have used simultaneous flow cytometry and DNA restriction enzyme analysis on 58 samples of tissue and blood to determine whether lymphocyte populations detected by "kappa/lambda" analysis are indeed monoclonal. In greater than 90% of cases, abnormalities detected by flow cytometry correlated with monoclonal rearrangements of immunoglobulin genes as detected by Southern blot analysis. By analyzing tissue and blood from the same patients, we have also demonstrated that monoclonal circulating cells detected by flow cytometry reflect peripheral circulating tumor cells, since DNA from these cells shows the same immunoglobulin rearrangement as DNA from the original tumors in these patients. Although mixing studies suggested that DNA rearrangement studies were more sensitive than was flow cytometry in detecting minor populations of monoclonal lymphocytes, we found only one case in which this affected the diagnostic accuracy of the kappa/lambda analysis, with one notable exception, that of detection of a monoclonal proliferation of B cells that did not express surface immunoglobulin. The kappa/lambda test thus offers a powerful diagnostic tool in the evaluation of lymphoproliferative disease.

DNA↗

Electrochemistry of conductive polymers. 34. Two-dimensional correlation analysis of real-time spectroelectrochemical data for aniline polymerization.

Electrochemical polymerization of aniline has been studied using real-time spectroelectrochemical experiments conducted concurrently with potentiodynamic scans in a nitric acid electrolyte with its pH adjusted to 0.50. Two-dimensional correlation spectral analysis and subsequent extraction of pure component spectra as well as their relative concentration profiles from complex spectroelectrochemical data employing the alternating least-squares regression iteration-based self-modeling curve resolution method led to positive identification of intermediate species. A conclusion was reached on the polymerization reaction mechanism based on these intermediate species and how their concentrations increased or decreased during the potential scans. The mechanism thus concluded represents a summary of a current understanding of the aniline polymerization reaction.

Journal Article↗

Correlational analysis of speakers' heights, weights, and temporal speech features.

Correlation coefficients on height, weight, and temporal features were computed separately for 15 female and 15 male speakers. With only one exception, speakers' heights and weights were not significantly correlated with their temporal characteristics. Implications of these findings and suggestions for future research are discussed.

Adolescent↗

Processing of histamine-induced itch in the human cerebral cortex: a correlation analysis with dermal reactions.

The subjective sensation of itch is a complex emotional experience depending on a variety of factors. In this study, the central nervous processing of pruritus was investigated in a human model. Activation of involved cerebral areas was correlated to scales of nociception and skin reactions. Six healthy male right-handed subjects participated in a standardized epidermal stimulus model with nine increasing doses of histamine dihydrochloride (0.03%-8%) on their right forearms. Controls consisted of three NaCl stimuli. Cerebral activation patterns were determined by H(2)(15)O positron emission tomography 120 s after stimulation. Dermal reactions to the stimulus (wheal, flare, temperature) were coregistered during the procedure. Itch sensation was determined by visual analog scale rating. Pain was not reported during the study; all volunteers had localized itch from 0.03% histamine on. Subtraction analysis versus control revealed significant activation of the left primary sensory cortex and motor-associated areas (mainly primary motor cortex, supplementary motor area, premotor cortex). Predominantly left-sided activations of frontal, orbitofrontal, and superior temporal cortex and anterior cingulate were also observed. Correlation analysis revealed coactivation of dermal reactions and cerebral response to itch in the following Brodmann areas with a Z score greater than 5: wheal, areas 5 (bilateral) and 19 (right); flare, areas 2-5 (left); temperature, area 10 (left) and left insula. Itch intensity ratings were mainly correlated with activation of the left sensory and motor areas. Functional covariates of the itch sensation in the central nervous system were identified. The intention to pruritofensive movements is probably mirrored by the activation of motor areas in the cortex. Other areas may be involved in emotional processing of sensations. Skin reactions wheal and flare also had significantly activated covariate areas in the central nervous system.J Invest Dermatol 115:1029-1033 2000

Adult↗

An image correlation analysis of the distribution of clathrin associated adaptor protein (AP-2) at the plasma membrane.

Clathrin associated adaptor protein is involved in endocytosis at the plasma membrane (AP-2) and protein sorting at the Golgi membrane (AP-1). There is a great deal of information available on the structure, function and binding characteristics of AP-2, however, there is little quantitative data on the AP-2 distribution at the membrane. Image correlation spectroscopy is a technique which yields number counts from an autocorrelation analysis of intensity fluctuations within confocal microscopy images. Image correlation spectroscopy analysis of the indirect immunofluorescence from AP-2 at the plasma membrane of CV-1 cells shows that AP-2 is in a bimodal distribution consisting of large coated pit associated aggregates of approximately 60 AP-2 molecules, and smaller aggregates containing approximately 20 AP-2 molecules, which we propose are coated pit nucleation sites. Following hypertonic treatment 25% of the AP-2 molecules dissociate from the large AP-2 aggregates and form AP-2 dimers, leaving the remaining AP-2 as large aggregates with approximately 45 molecules. The smaller AP-2 aggregates completely dissociate forming AP-2 dimers. Dispersion of AP-2 with hypertonic treatment is not seen qualitatively because the number of large AP-2 aggregates is unchanged, the aggregates are just 25% smaller. Change in temperature from 37 degrees C to 4 degrees C has no affect on the number of AP-2 aggregates or the AP-2 distribution between the two populations. These data and estimates of the coated pit size suggest that coated pits cover approximately 0.9% of the cell membrane. Combination of image correlation spectroscopy analysis and measurements of the CV-1 cell surface area show that there are approximately 6x10(5) AP-2 molecules per CV-1 cell with approximately 2x10(5) AP-2 molecules within coated pit structures.

Adaptor Proteins, Vesicular Transport↗

[A spectral-correlational analysis of the EEG of the neocortex in the rabbit in a state of thirst].

Summate electrical activity of the rabbit neocortex during formation of drinking excitation was studied by means of mathematical analysis. It is shown that the change of the electrical activity depends on the level of drinking excitability created by various duration of water deprivation (24-48 h) and is expressed in a generalized lowering of potentials amplitude without frequency change. Spectro-correlative EEG analysis showed that lowering of spectrum power took place within the whole analyzed frequencies range. Besides, an increase took place of interconnections of the cortical electrical processes, estimated by coherence function. It may by suggested that the manifested reconstruction of spectro-correlative characteristics of the neocortical biopotentials reflects a formation of motivational excitation establishing optimal level of cortex functioning.

Animals↗

Comparative study of retinal nerve fiber layer measurement by StratusOCT and GDx VCC, I: correlation analysis in glaucoma.

PURPOSE: To evaluate the average and regional correlations of retinal nerve fiber layer (RNFL) thickness measured by StratusOCT (optical coherence tomography; Carl Zeiss Meditec, Inc., Dublin, CA) and GDx VCC (Laser Diagnostic Technologies, Inc., San Diego, CA). METHODS: Eighty-nine subjects-27 normal, 21 with suspected glaucoma, and 41 with glaucoma-were included in this cross-sectional study. The total average and the mean 12-clock-hour RNFL thickness were measured with the StratusOCT and GDx VCC. The discriminating powers of the two techniques for detection of suspected glaucoma and glaucoma were compared by the area under the receiver operating characteristic curves (AUC). Correspondence between StratusOCT and GDx VCC RNFL measurements in each clock hour was examined with linear regression analysis. RESULTS: The average RNFL thickness in the normal group was measured at 101.38 +/- 7.73 and 55.26 +/- 4.32 mum by StratusOCT and GDx VCC, respectively. Both nerve fiber analyzers demonstrated a double-hump pattern in the RNFL profiles with maximum RNFL thickness located at the inferotemporal and superotemporal clock hours by the StratusOCT and the superior and inferior clock hours by the GDx VCC. Significant differences were found in the total average and the individual clock-hour RNFL thickness between StratusOCT and GDx VCC RNFL measurements in both the normal and the suspected glaucoma/glaucoma groups. The GDx VCC superior RNFL measurement demonstrated the largest AUC (0.909) for detection of suspected glaucoma and glaucoma, whereas the largest AUC (0.901) in StratusOCT was found over the inferotemporal clock hour. The total average RNFL thickness measured with StratusOCT and GDx VCC correlated highly with each other (r = 0.852). When the respective clock-hour RNFL measurements were compared, the correlation coefficient varied with the position around the optic nerve head, with the highest correlation found over the superior and inferior clock hours (11, 12, 1, 6, and 7 o'clock; all with r > 0.700) and the lowest located at the temporal clock hour (9 o'clock; r = 0.277). CONCLUSIONS: Despite the substantial differences in the values of RNFL thickness, significant correlations were observed between StratusOCT and GDx VCC RNFL measurements. The variations of the correlation coefficient around the optic nerve head suggested that GDx VCC RNFL measurement does not have a fixed relationship with that of StratusOCT and the use of site-specific RNFL birefringences may improve the estimation of RNFL thickness by the GDx VCC. Nevertheless, the GDx VCC was found to be as effective as the StratusOCT in detecting the loss of RNFL in glaucoma.

Birefringence↗

Protein structure similarity from Principle Component Correlation analysis.

BACKGROUND: Owing to rapid expansion of protein structure databases in recent years, methods of structure comparison are becoming increasingly effective and important in revealing novel information on functional properties of proteins and their roles in the grand scheme of evolutionary biology. Currently, the structural similarity between two proteins is measured by the root-mean-square-deviation (RMSD) in their best-superimposed atomic coordinates. RMSD is the golden rule of measuring structural similarity when the structures are nearly identical; it, however, fails to detect the higher order topological similarities in proteins evolved into different shapes. We propose new algorithms for extracting geometrical invariants of proteins that can be effectively used to identify homologous protein structures or topologies in order to quantify both close and remote structural similarities. RESULTS: We measure structural similarity between proteins by correlating the principle components of their secondary structure interaction matrix. In our approach, the Principle Component Correlation (PCC) analysis, a symmetric interaction matrix for a protein structure is constructed with relationship parameters between secondary elements that can take the form of distance, orientation, or other relevant structural invariants. When using a distance-based construction in the presence or absence of encoded N to C terminal sense, there are strong correlations between the principle components of interaction matrices of structurally or topologically similar proteins. CONCLUSION: The PCC method is extensively tested for protein structures that belong to the same topological class but are significantly different by RMSD measure. The PCC analysis can also differentiate proteins having similar shapes but different topological arrangements. Additionally, we demonstrate that when using two independently defined interaction matrices, comparison of their maximum eigenvalues can be highly effective in clustering structurally or topologically similar proteins. We believe that the PCC analysis of interaction matrix is highly flexible in adopting various structural parameters for protein structure comparison.

Algorithms↗

Comment on a "fluctuation and cross correlation analysis of protein motions observed in nanosecond molecular dynamics simulations".

Long range positive correlations in the internal atomic motions have been observed in molecular dynamics simulations of the bovine pancreatic trypsin inhibitor. Since the results depend on the removal of overall translation and rotation (which is not unique), some care is required. It is pointed out that original use of all of the C atoms as a frame of reference is more appropriate than the selection of a particular subset. The former comes closest to reflecting the zero rotation condition in a normal mode analysis, which also shows the existence of long range correlations.

Animals↗

Brief interval heart period variability by different methods of analysis correlates highly with 24 h analyses in normals.

Heart period variability (HPV) measured from 24 h ECG recordings predicts mortality following myocardial infarction and may be a measure of cardiovascular health in the general population. Since epidemiologic evaluation of healthy people will require alternatives less intensive than 24 h recording, we investigated the relationship between HPV derived from 24 h and 5 min recordings, using two approaches for obtaining RR intervals. Template-matching (TM) algorithms were applied to 24 h ECG recordings from 41 normal subjects (mean age 35.7 +/- 13 years). Five min of ECG data during this 24 h period also were collected by an on-line microcomputer-based system for peak detection (PD) analysis. Intraclass correlations comparing the TM and PD approaches on the 5 min period were .80 or greater for all measures of HPV. Pearson correlation coefficients between the 5 min (TM) estimates and 24 h data and 5 min (PD) estimates and 24 h data exceeded .60 and .55, respectively, for all but one variable, with all p values < .05. Thus, in healthy adults, TM and PD approaches to HPV estimation from short segments of ECG data are highly consistent and the correlations between HPV obtained from brief intervals and 24 h measures were substantial, suggesting that assessment of HPV as a screening measure of cardiac autonomic control in healthy adults may be feasible.

Adult↗