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Multiple Samples (multiple + sample)

Distribution by Scientific Domains

Life Sciences	29%
Medical Sciences	20%
Chemistry	20%
Earth and Environmental Science	12%

Selected Abstracts

Bayesian Robust Inference for Differential Gene Expression in Microarrays with Multiple Samples

BIOMETRICS, Issue 1 2006
Raphael Gottardo
Summary We consider the problem of identifying differentially expressed genes under different conditions using gene expression microarrays. Because of the many steps involved in the experimental process, from hybridization to image analysis, cDNA microarray data often contain outliers. For example, an outlying data value could occur because of scratches or dust on the surface, imperfections in the glass, or imperfections in the array production. We develop a robust Bayesian hierarchical model for testing for differential expression. Errors are modeled explicitly using a t -distribution, which accounts for outliers. The model includes an exchangeable prior for the variances, which allows different variances for the genes but still shrinks extreme empirical variances. Our model can be used for testing for differentially expressed genes among multiple samples, and it can distinguish between the different possible patterns of differential expression when there are three or more samples. Parameter estimation is carried out using a novel version of Markov chain Monte Carlo that is appropriate when the model puts mass on subspaces of the full parameter space. The method is illustrated using two publicly available gene expression data sets. We compare our method to six other baseline and commonly used techniques, namely the t -test, the Bonferroni-adjusted t -test, significance analysis of microarrays (SAM), Efron's empirical Bayes, and EBarrays in both its lognormal,normal and gamma,gamma forms. In an experiment with HIV data, our method performed better than these alternatives, on the basis of between-replicate agreement and disagreement. [source]

Near-diploid and near-triploid human sporadic colorectal adenocarcinomas differ for KRAS2 and TP53 mutational status

GENES, CHROMOSOMES AND CANCER, Issue 2 2003
Walter Giaretti
Mutations of the KRAS2 protoncogene and inactivation of the TP53 oncosuppressor gene have been suggested to contribute to chromosomal instability (CIN) and aneuploidy in colorectal cancer (CRC). Previous work has also shown that the degree of DNA ploidy [DNA index (DI)], as obtained by flow cytometry in CRC, is non-randomly distributed and, in particular, that DI near-diploid and near-triploid values are well separated by a low-probability valley region. At present, it is not known whether a relationship exists between DI and the mutational status of KRAS2 and TP53. Multiple samples obtained from 35 human sporadic CRCs have been used to provide nuclei suspensions for flow cytometric analysis and sorting of specific DI subpopulations. Sorted nuclei were then used to analyze the high-microsatellite-instability (MSI-H) phenotype and the mutation spectrum of the KRAS2 and TP53 genes. A single MSI-H case was detected. There were 6 DNA diploid (DI = 1) and 29 aneuploid (DI , 1) CRCs, with the DI aneuploid cases non-randomly subdivided in 9 near-diploid (DI , 1 and DI , 1.4), 8 near-triploid (1.4 < DI < 1.6), and 12 high-aneuploid (DI , 1.6) cases. Proximal CRCs were more often DNA diploid and near-diploid than distal ones, and Dukes' C cases were more commonly high-aneuploid than Dukes' B. Moreover, the incidence of mutations of the KRAS2 and TP53 genes was lowest among the DNA near-triploid subpopulations and highest among the near-diploid ones. We suggest that DNA near-diploid and near-triploid subpopulations in human sporadic CRC reflect different genetic mechanisms of CIN and have a potentially different clinical behavior. © 2003 Wiley-Liss, Inc. [source]

High-throughput screening of chemical exchange saturation transfer MR contrast agents

CONTRAST MEDIA & MOLECULAR IMAGING, Issue 3 2010
Guanshu Liu
Abstract A new high-throughput MRI method for screening chemical exchange saturation transfer (CEST) agents is demonstrated, allowing simultaneous testing of multiple samples with minimal attention to sample configuration and shimming of the main magnetic field (B0). This approach, which is applicable to diamagnetic, paramagnetic and liposome CEST agents, employs a set of inexpensive glass or plastic capillary tubes containing CEST agents put together in a cheap plastic tube holder, without the need for liquid between the tubes to reduce magnetic susceptibility effects. In this setup, a reference image of direct water saturation spectra is acquired in order to map the absolute water frequency for each volume element (voxel) in the sample image, followed by an image of saturation transfer spectra to determine the CEST properties. Even though the field over the total sample is very inhomogeneous due to air,tube interfaces, the shape of the direct saturation spectra is not affected, allowing removal of susceptibility shift effects from the CEST data by using the absolute water frequencies from the reference map. As a result, quantitative information such as the mean CEST intensity for each sample can be extracted for multiple CEST agents at once. As an initial application, we demonstrate rapid screening of a library of 16 polypeptides for their CEST properties, but in principle the number of tubes is limited only by the available signal-noise-ratio, field of view and gradient strength for imaging. Copyright © 2010 John Wiley & Sons, Ltd. [source]

A label-free protein microfluidic array for parallel immunoassays

ELECTROPHORESIS, Issue 20 2006
Zhan-Hui Wang
Abstract A label-free protein microfluidic array for immunoassays based on the combination of imaging ellipsometry and an integrated microfluidic system is presented. Proteins can be patterned homogeneously on substrate in array format by the microfluidic system simultaneously. After preparation, the protein array can be packed in the microfluidic system which is full of buffer so that proteins are not exposed to denaturing conditions. With simple microfluidic channel junction, the protein microfluidic array can be used in serial or parallel format to analyze single or multiple samples simultaneously. Imaging ellipsometry is used for the protein array reading with a label-free format. The biological and medical applications of the label-free protein microfluidic array are demonstrated by screening for antibody,antigen interactions, measuring the concentration of the protein solution and detecting five markers of hepatitis,B. [source]

Microautosamplers for discrete sample injection and dispensation

ELECTROPHORESIS, Issue 9 2005
Chun-Wei Huang
Abstract Microfluidic systems show considerable potential for use in the continuous reaction and analysis of biosamples for various applications, such as drug screening and chemical synthesis. Typically, microfluidic chips are externally connected with large-scale autosamplers to inject specific volumes of discrete samples in the continuous monitoring and analysis of multiple samples. This paper presents a novel microelectromechanical system (MEMS)-based autosampler capable of performing the discrete injection and dispensation of variable-volume samples. This microdevice can be integrated with other microfluidic devices to facilitate the continuous monitoring and analysis of multiple biosamples. By means of electroosmotic focusing and switching controlled by the direct application of electric sources on specific fluid reservoirs, a precise sample volume can be injected into the specified outlet port. Fluorescence dye images verify the performance of the developed device. An injection-and-washing scheme is developed to prevent cross-contamination during the continuous injection of different samples. This approach renders feasible the injection of several discrete samples using a single microchip. Compared to its large-scale counterparts, the developed microautosampler is compact in size, has low fabrication costs, is straightforward to control, and most importantly, is readily integrated with other microfluidic devices (e.g., microcapillary electrophoresis chips) to form a microfluidic system capable of the continuous monitoring and analysis of bioreactions. The proposed microautosampler could be promising towards realizing the micrototal analysis system (,-TAS) concept. [source]

A microfabricated capillary electrophoresis chip with multiple buried optical fibers and microfocusing lens for multiwavelength detection

ELECTROPHORESIS, Issue 6 2005
Suz-Kai Hsiung
Abstract We present a new microfluidic device utilizing multiwavelength detection for high-throughput capillary electrophoresis (CE). In general, different fluorescent dyes are only excited by light sources with appropriate wavelengths. When excited by an appropriate light source, a fluorescent dye emits specific fluorescence signals of a longer wavelength. This study designs and fabricates plastic micro-CE chips capable of performing multiple-wavelength fluorescence detection by means of multimode optic fiber pairs embedded downstream of the separation channel. For detection purposes, the fluorescence signals are enhanced by positioning microfocusing lens structures at the outlets of the excitation fibers and the inlets of the detection fibers, respectively. The proposed device is capable of detecting multiple samples labeled with different kinds of fluorescent dyes in the same channel in a single run. The experimental results demonstrate that various proteins, including bovine serum albumin and ,-casein, can be successfully injected and detected by coupling two light sources of different wavelengths to the two excitation optic fibers. Furthermore, the proposed device also provides the ability to measure the speed of the samples traveling in the microchannel. The developed multiwavelength micro-CE chip could have significant potential for the analysis of DNA and protein samples. [source]

Personality traits and health-risk behaviours in university students

EUROPEAN JOURNAL OF PERSONALITY, Issue 8 2009
Ryan Y. Hong
Abstract Relations between personality and health-risk behaviours in university undergraduates were examined using multiple measures of personality across multiple samples (N,=,1151). Big Five personality variables, at both factor and facet levels, were used to predict three specific health-risk behaviours: (a) tobacco consumption, (b) alcohol consumption and (c) speeding in an automobile. Our findings showed that low Conscientiousness and low Agreeableness were uniformly associated with this cluster of potentially health damaging behaviours. Extraversion was additionally associated with alcohol use. Interaction effects were found between Conscientiousness and Agreeableness on smoking and (for men only) on drinking. Other personality variables not centrally related to the Big Five, such as Risk-Taking (high) and Integrity (low), were also implicated in the present health-risk behaviours. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Real-time quadrupole mass spectrometer analysis of gas in borehole fluid samples acquired using the U-tube sampling methodology

GEOFLUIDS (ELECTRONIC), Issue 3 2006
B. M. FREIFELD
Abstract Sampling of fluids in deep boreholes is challenging because of the necessity of minimizing external contamination and maintaining sample integrity during recovery. The U-tube sampling methodology was developed to collect large volume, multiphase samples at in situ pressures. As a permanent or semi-permanent installation, the U-tube can be used for rapidly acquiring multiple samples or it may be installed for long-term monitoring applications. The U-tube was first deployed in Liberty County, TX to monitor crosswell CO2 injection as part of the Frio CO2 sequestration experiment. Analysis of gases (dissolved or separate phase) was performed in the field using a quadrupole mass spectrometer, which served as the basis for determining the arrival of the CO2 plume. The presence of oxygen and argon in elevated concentrations, along with reduced methane concentration, indicates sample alteration caused by the introduction of surface fluids during borehole completion. Despite producing the well to eliminate non-native fluids, measurements demonstrate that contamination persists until the immiscible CO2 injection swept formation fluid into the observation wellbore. [source]

Comparing methods for analysing mortality profiles in zooarchaeological and palaeontological samples

INTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 6 2005
T. E. Steele
Abstract In this study, I examine three methods that are currently used for comparing mortality profiles from zooarchaeological and palaeontological samples: (1) histograms with 10% of life-span age classes; (2) boxplots showing tooth crown height medians; and (3) triangular plots of the proportions of young, prime and old animals. I assess the advantages and disadvantages of each method using data collected on two samples of Northern Yellowstone elk (Cervus elaphus nelsoni) with known, or cementum annuli-determined, ages at death. One sample was hunted by wolves (n,=,96), and the other was hunted by recent humans using rifles (n,=,226). I tested each method with the known or cementum annuli age distributions and with age estimation techniques appropriate for archaeological assemblages. Histograms are best used when the relationship between dental eruption/attrition and age is well established so that individuals can be confidently assigned into 10% of life-span groups, and when more than 30 or 40 individuals are present in the assemblage. Boxplots employ raw crown heights, thus removing the error introduced by assigning specimens to age classes, and therefore they allow the analysis of species where the relationship between dental eruption/attrition and age is unknown. Confidence intervals around the medians allow samples to be statistically compared. Triangular plots are easy to use and allow multiple samples and species to be considered simultaneously, but samples cannot be statistically compared. Modified triangular plots bootstrap samples to provide 95% confidence ellipses, allowing for statistical comparisons between samples. When possible, samples should be examined using multiple methods to increase confidence in the results. Copyright © 2005 John Wiley & Sons, Ltd. [source]

The relationship between flesh quality and numbers of Kudoa thyrsites plasmodia and spores in farmed Atlantic salmon, Salmo salar L.

JOURNAL OF FISH DISEASES, Issue 8 2003
J A Dawson-Coates
Abstract Atlantic salmon, Salmo salar L., were exposed to Kudoa thyrsites (Myxozoa, Myxosporea)-containing sea water for 15 months, and then harvested and assessed for parasite burden and fillet quality. At harvest, parasites were enumerated in muscle samples from a variety of somatic and opercular sites, and mean counts were determined for each fish. After 6 days storage at 4 °C, fillet quality was determined by visual assessment and by analysis of muscle firmness using a texture analyzer. Fillet quality could best be predicted by determining mean parasite numbers and spore counts in all eight tissue samples (somatic and opercular) or in four fillet samples, as the counts from opercular samples alone showed greater variability and thus decreased reliability. The variability in both plasmodia and spore numbers between tissue samples taken from an individual fish indicated that the parasites were not uniformly distributed in the somatic musculature. Therefore, to best predict the probable level of fillet degradation caused by K. thyrsites infections, multiple samples must be taken from each fish. If this is performed, a mean plasmodia count of 0.3 mm,2 or a mean spore count of 4.0 × 105 g,1 of tissue are the levels where the probability of severe myoliquefaction becomes a significant risk. [source]

Development of an Antibody Hapten-Chip System for Detecting the Residues of Multiple Antibiotic Drugs,

JOURNAL OF FORENSIC SCIENCES, Issue 4 2009
Ailiang Chen M.Sc.
Abstract:, The abuse of antibiotic drugs during animal production remains a worldwide problem and the subsequent detection of the residues of various drugs present at low concentrations in complex biological matrices poses significant analytical challenges. The present study outlines a practical biochip assay system to identify antibiotic residues in different animal tissue extracts. The system uses a simple but efficient multiresidue sample extraction procedure to isolate the antibiotic residues which were then identified directly using high-affinity monoclonal antibodies presented in a competitive immunoassay with conjugated antibiotic hapten-chips. The hapten-chip can analyze six samples each for eight antibiotics on a single chip within 3 h. The analytical results with both artificial positive standard samples and the incurred samples show that the antibody hapten-chip system has a comparable accuracy and a similar sensitivity to a standard ultra performance liquid chromatography,mass spectrometry (MS)/MS assay. In conclusion, an effective analytical screening system based on antibody hapten-chip was developed for detecting multiple antibiotic residues from multiple samples. [source]

Forensic Age-at-Death Estimation from the Human Sacrum,

JOURNAL OF FORENSIC SCIENCES, Issue 2 2009
Nicholas V. Passalacqua M.S.
Abstract:, A new method is described here that incorporates seven developmental and degenerative changes for estimating chronological age from morphological features of the human sacrum. The construction of this method involved multiple stages of trait identification, character-state definition and age correlation, rank-order phase development, and percent-correct sample testing with phase and sample aggregation, all of which resulted in a six-phase component system for application on modern individuals. This phase system was first developed on European American male and female samples from the Hamann-Todd collection; then tested on African American male and female Hamann-Todd samples as well as European American male and females from the WM Bass collection to examine possible sex and/or ancestry differences. Variation in age estimates due to sex and ancestry was negligible; thus, the multiple samples were all pooled creating a robust method with a large sample size. Overall age ranges increase in width at two standard deviations as is expected from degenerative age-related processes but retain utility in forensic situations. [source]

HIV antigen,antibody combination enzyme immunoassay,the experience of a London Teaching Hospital

JOURNAL OF MEDICAL VIROLOGY, Issue S1 2007
Simon Goldenberg
Abstract The introduction of the fourth generation HIV antigen,antibody combination enzyme immunoassay (HIV Ag,Ab EIA) has led to a reduction in the diagnostic "window period" when HIV antibody is negative during primary infection. This facilitates earlier laboratory diagnosis during sero-conversion. An HIV Ag,Ab EIA (AxSYM, Abbott Laboratories, Kent, UK) was introduced to a London Teaching Hospital since 2004 as the primary screening test. Confirmation was performed using another HIV Ag,Ab EIA (Vironostika, BioMérieux, Hampshire, UK) and an HIV Ab only assay (Bispot, Orgenics, Yavne, Israel). Retrospective analysis identified a total of 20 sero-converting patients who would have been missed if the standard antibody-only HIV tests had been used as the primary screening test. This accounted for approximately 3% of the new diagnoses made by the laboratory. The median time from onset of illness to sero-conversion was 18 days. Two patients had multiple samples analyzed between initial presentation and eventual sero-conversion. One had a prolonged sero-conversion illness lasting for over 137 days; the other sero-converted within 17 days. A plotting of the signal to cut-off ratio with time of the two HIV Ag,Ab EIAs showed a V-shaped curve and both tests were below cut-off at some time-points during sero-conversion. These two cases highlighted the difficulties in diagnosing HIV infection during sero-conversion. On the basis of these results, it is recommended that a fourth generation HIV Ag,Ab EIA could be considered for use as the standard of care, particularly in any population with a high rate of HIV infection. J. Med. Virol. 79:S23,S26, 2007. © 2007 Wiley-Liss, Inc. [source]

Is Depressive Symptomatology Associated with Worse Oral Functioning and Well-being Among Older Adults?

JOURNAL OF PUBLIC HEALTH DENTISTRY, Issue 1 2002
Nancy R. Kressin PhD;
Abstract Objectives: Although depression negatively affects individuals' physical functioning and well-being, its association with oral functioning and well-being has not been examined previously. The objective of this study was to examine the association between depressive symptomatology and oral quality of life. Methods: We utilized data from two samples of older adults: community-dwelling participants who used community primary care physicians in Los Angeles (n=7,653) and individuals who sought ambulatory care through four Department of Veterans Affairs facilities in the Boston metropolitan area (n=212). Depressive symptomatology was measured with the CES-D scale; Oral Quality of Life was measured with the Geriatric Oral Health Assessment Instrument and the Oral Health-related Quality of Life measure. We conducted hierarchical regression analyses to examine the effects of depression on oral quality of life, controlling for self-reported oral health, age, education, income, and marital status. Results: Individuals with more depressive symptoms reported worse oral quality of life, controlling for socio demographic factors and self-reported oral health. This finding persisted across multiple samples and both sexes, and using two measures of oral quality of life. Conclusion: These findings further emphasize the importance of treating depression among older adults, and suggest that both dentists and physicians have a role in recognizing and referring patients for such treatment. [source]

Quantitative evaluation of the interaction between netropsin and double stranded oligodeoxynucleotides by microfabricated capillary array electrophoresis

JOURNAL OF SEPARATION SCIENCE, JSS, Issue 10 2007
Zheng Shen
Abstract Microfabricated capillary array electrophoresis (,-CAE) was applied to study the interaction between minor groove binder netropsin and a non-selfcomplementary 12 mer double stranded oligodeoxynucleotide: d(CCCCTATACCGC)·d(GCGGTATAGGGG). ESI-MS was used to provide an independent verification of the microchip electrophoresis derived data. Simultaneous parallel quantitative assay of multiple samples was performed in a single run (<50 s) on the self-developed ,-CAE device. The binding constant and stoichiometry calculated from Scatchard plot were (2.88 ± 0.23)×105 M,1 and 1:1, respectively. The values showed a good quantitative agreement with the results determined by ESI-MS and those using other methods reported in the literature. [source]

Parallel separations of oligonucleotides with optically gated sample introduction on multi-channel microchips

JOURNAL OF SEPARATION SCIENCE, JSS, Issue 1-2 2004
Hongwei Xu
Abstract With the release of the human genome sequence, there has been increasing attention given to other genetic analyses, including the detection of genetic variations and fast sequencing of multiple samples for pharmacogenomics studies. Rapid injections of samples in multiplexed separation channels by optically gated sample introduction are shown here for DNA separation. Serial separations of four amino acids are shown in less than four seconds on a microchip with four multiplexed channels. Five short oligonucleotides have also been rapidly separated in 2% LPA with four channels using this technique. In addition, multiple unique samples have been simultaneously separated and five-base resolution has been demonstrated. [source]

Rapid preparation of cyanobacterial DNA for real-time PCR analysis

LETTERS IN APPLIED MICROBIOLOGY, Issue 1 2008
J.P. Rasmussen
Abstract Aims:, To develop a rapid preparation method for real-time PCR analysis of cyanobacteria from cultures or field samples. Methods and Results:, Field samples and cultures containing Anabaena circinalis, Cylindrospermopsis raciborskii or Microcystis aeruginosa were subjected to three cell disruption treatments: (i) heating during thermocycling, (ii) microwave irradiation in the presence of detergent and (iii) probe sonication. Treated samples were directly added to the PCR reaction and analysed on two different real-time devices. A statistically significant difference was evident in the cycle thresholds for each of the treatments in all but one culture and one environmental sample, sonication and microwave treatments performing better than direct addition. The microwave treatment was also compared to the Qiagen DNA Mini kit and performance was equivalent when treated samples were analysed as above. Conclusions:, Whilst microwave treatment was slightly less effective than probe sonication across all samples, it was more amenable to processing multiple samples and significantly better than heat treating the sample during thermocycling. Significance and Impact of the Study:, The microwave method described here is a simple, rapid and effective preparation method for cyanobacterial DNA that can be easily deployed in the field, making the most of the speed and flexibility offered by fixed and portable real-time PCR devices. [source]

CGH in the detection of confined placental mosaicism (CPM) in placentas of abnormal pregnancies

PRENATAL DIAGNOSIS, Issue 9 2002
A. Amiel
Abstract Comparative genomic hybridization (CGH) was applied to samples taken from various sites of placentas originating from complicated pregnancies: 24 with intrauterine growth restriction (IUGR), one with multiple fetal malformation, one with toxemia, one with hydrocephalus and two with undetectable maternal serum alpha-fetoprotein (MSAFP). One of the most common aberrations in the IUGR cases was the addition of a whole or part of the X chromosome. Other aberrations such as additional Y chromosome or of 13(q22) or loss of chromosome 17 also appeared in different cases. In one IUGR case trisomy 8 (in one site) and 47,XXY (in all sites) were detected. In the two cases with undetectable MSAFP monosomy 16 was found. Some of the results were also confirmed by the FISH technique. In all the control cases (six normal and five with aneuploidy) CGH concurred with the known karyotype. Our results demonstrate the usefulness of the CGH technique in the genetic evaluation of fresh and paraffin embedded placentas in problematic pregnancies even when morphology is normal. However, it is very important to take multiple samples from different sites of the placenta. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Plasma protein profiling: Unique and stable features of individuals

PROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 15 2005
Gary L. Nelsestuen Dr.
Abstract Carefully controlled ZipTip extraction of diluted human plasma or serum was combined with MALDI-TOF-MS to produce highly reproducible protein profiles. Components detected included apolipoproteins CI, CII and CIII as well as transthyretin and several isoforms of each protein that are created by glycosylation or other modification and by proteolytic processing. Profiles of healthy individuals all contained the same 15,components. Others were found in plasma from individuals with disease. Profiles were analyzed by peak ratios within the same spectrum. Reproducibility for multiple assays was generally 4 to 10%. Within the healthy population, a given peak ratio occurred with a range of about fourfold. However, peak ratios of multiple samples from the same individual showed a much lower range, typically ±10%. In fact, each individual displayed a personal protein profile that changed very little over time. Because of the stability of protein profiles over time within individuals, these results suggest further studies may discover that certain profile characteristics or changes in an individual's profile may be a sign of current or future disease, even when the altered profile remains within the range for healthy individuals. [source]

Type 2 Diabetes Susceptibility Genes on Chromosome 1q21,24

ANNALS OF HUMAN GENETICS, Issue 2 2008
S. J. Hasstedt
Summary Type 2 diabetes (T2D) has been linked to chromosome 1q21,24 in multiple samples, including a Utah family sample. Variants in 13 of the numerous candidate genes in the 1q region were tested for association with T2D in a Utah case-control sample. The most promising, 19 variants in 6 candidates, were genotyped on the Utah family sample. Herein, we tested the 19 variants individually and in pairs for an effect on T2D risk in family members using a logistic regression model that accounted for gender, age, and BMI and attributed residual genetic effects to a polygenic component. Seven variants increased risk significantly through 5 pairs of interactions. The significant variant pairs were apolipoprotein A-II (APOA2) rs6413453 interacting with calsequestrin 1 (CASQ1) rs617698, dual specificity phosphatase 12 (DUSP12) rs1503814, and retinoid X receptor , (RXRG) rs10918169, a poly-T insertion-deletion polymorphism in liver pyruvate kinase (PKLR) interacting with APOA2 rs12143180, and DUSP12 rs1027702 interacting with RXRG rs10918169. Genotypes of these 5 variant pairs accounted for 25.8% of the genetic variance in T2D in these pedigrees. [source]

Antibodies to apolipoprotein A-I, high-density lipoprotein, and C-reactive protein are associated with disease activity in patients with systemic lupus erythematosus

ARTHRITIS & RHEUMATISM, Issue 3 2010
Sean G. O'Neill
Objective Inflammatory disease activity in patients with systemic lupus erythematosus (SLE) may affect the development of atherosclerosis, contributing to their increased risk of cardiovascular disease (CVD). This process may be mediated by anti,apolipoprotein A-I (anti,Apo A-I), anti,high-density lipoprotein (anti-HDL), and anti,C-reactive protein (anti-CRP) autoantibodies. We undertook this study to examine whether levels of these antibodies rise in association with increased SLE disease activity. Methods IgG anti,Apo A-I, anti-HDL, and anti-CRP levels were measured in serum from the following groups: 39 patients with persistently high disease activity (British Isles Lupus Assessment Group [BILAG] A or B score) over the previous 2 years, 42 patients with persistently low disease activity (no BILAG A or B scores) over the previous 2 years, 34 healthy controls, 25 individual patients from whom paired samples (at time of disease flare and quiescence) were obtained and compared, 16 patients with newly diagnosed lupus nephritis from whom multiple samples were obtained and who were followed up prospectively for up to 2 years, and 24 patients with SLE who had experienced CVD events. Results Serum levels of IgG anti,Apo A-I, anti-HDL, and anti-CRP were higher in patients with SLE than in controls. Anti,Apo A-I and anti-HDL levels, but not anti-CRP levels, were higher in patients with persistently high disease activity than in those with low disease activity. Mean levels of the 3 autoantibodies in patients who had experienced CVD events lay between the mean levels in the high and low disease activity groups. Only levels of anti,Apo A-I were significantly higher in samples obtained from individual patients during disease flares than in samples obtained during disease quiescence. In the lupus nephritis patients, anti,Apo A-I and anti-HDL levels correlated with serum levels of high avidity IgG anti,double-stranded DNA. Conclusion Persistent disease activity is associated with a significant increase in IgG anti,Apo A-I and anti-HDL in patients with SLE. [source]

Comparison of girth materials, girth tensions and their effects on performance in racehorses

AUSTRALIAN VETERINARY JOURNAL, Issue 1-2 2005
J BOWERS
Objective To compare the effect of girth materials and commonly used girth tensions on athletic performance of racehorses and to test the length tension properties of commercially available girths. Procedure Seven horses were exercised at speeds to produce 95% of maximal heart rates on 15 occasions using a randomised block design, and girthed with 5 different girths at 3 nominal tensions of 6, 12 or 18 kg. The girths used were a standard elastic race girth, an ,American' elastic race girth, an elastic race girth twice the normal width, a standard canvas race girth and a canvas race girth at twice the normal width. Tension in the girth was recorded continuously using an in-line load cell connected to a physiograph. Horses ran to fatigue on a treadmill inclined at 10% slope. Tensions were measured at peak inhalation (T/inh) and exhalation (T/exh), recorded at rest (rest) and during exercise (ex). An analysis of variance was used to compare the mean run to fatigue times (RTFT) between girth types and tensions, multiple pair-wise comparisons were then carried out using Tukey's test where significant differences were found. The length-tension relationships of five commercially available girths for training and racing of Thoroughbred racehorses were studied by the application of standardized weights in series to multiple samples of each type of girth. Measurements were taken in a controlled environment and analysis of variance was used to compare the means for length-tension of each girth type. Results The elastic and the ,American' elastic girths produced significantly longer RTFT when compared to the standard canvas girth (P=0.01 and P = 0.001 respectively). Also girths tensioned at Texhrest 6 kg and Texhrest 12 kg produced significantly longer RTFT than when girthed at Texhrest 18 kg (P=0.03 and P = 0.08 respectively). There were significant differences between the commercially available girth types at each tension (P < 0.05), but differences were not significant between girths of the same type. Girths with an elastic component reached their peak for maximum extension at 14.5 kg and thereafter their extension declined. Conclusion The type of girth and the tension at which it is applied affects athletic performance. Lower girth tensions and the use of elastic materials in the girth would appear to optimise performance. However according to this study and our previous study, none of the commercially available girths studied would adequately protect against the potentially detrimental effects of overtightening on athletic performance. [source]

Segmentation and Estimation for SNP Microarrays: A Bayesian Multiple Change-Point Approach

BIOMETRICS, Issue 3 2010
Yu Chuan Tai
Summary High-density single-nucleotide polymorphism (SNP) microarrays provide a useful tool for the detection of copy number variants (CNVs). The analysis of such large amounts of data is complicated, especially with regard to determining where copy numbers change and their corresponding values. In this article, we propose a Bayesian multiple change-point model (BMCP) for segmentation and estimation of SNP microarray data. Segmentation concerns separating a chromosome into regions of equal copy number differences between the sample of interest and some reference, and involves the detection of locations of copy number difference changes. Estimation concerns determining true copy number for each segment. Our approach not only gives posterior estimates for the parameters of interest, namely locations for copy number difference changes and true copy number estimates, but also useful confidence measures. In addition, our algorithm can segment multiple samples simultaneously, and infer both common and rare CNVs across individuals. Finally, for studies of CNVs in tumors, we incorporate an adjustment factor for signal attenuation due to tumor heterogeneity or normal contamination that can improve copy number estimates. [source]