Project description:Comparative genomic hybridization microarrays (array CGH or molecular karyotyping) for the detection of congenital chromosomal aberrations is the application of microarray technology that is coming fastest into routine clinical application. When using a two-channel microarray of genomic DNA probes for array CGH, the basic setup consists in hybridizing a patient sample against a normal reference sample and detecting copy number variations through the deviation of fluorescent signal intensity between patient and normal reference. Two major disadvantages of this setup are (1) the use of half of the resources to measure a (little informative) reference sample and (2) the possibility that deviating signals are caused by benign copy number variation in the “normal” reference instead of a patient aberration. We therefore propose a new experimental loop design that compares three patients in three hybridizations (Patient 1 vs. Patient 3, Patient 3 vs. Patient 2, and Patient 2 vs. Patient 1). We develop and compare two statistical methods (linear models of log ratios and mixed models of absolute measurements). In an analysis of data from 27 patients seen at our genetics center, this new setup together with the linear model analysis significantly overcomes the limitations of the classical setup. Furthermore, we observed that the linear models of the log-ratios had a higher signal-to-noise ratio than the mixed models of the absolute intensities. These improvements are important to guarantee a maximal efficiency of array CGH in a clinical setting and will therefore contribute to its quick adoption as a routine diagnostic tool. The method is implemented as a web application and is available at www.esat.kuleuven.be/loop. Keywords: comparative genomic hybridization
Project description:The goal of the study was to identify molecular subgroups that might predict clinical outcomes in serous epithelial ovarian cancer (EOC) patients. A second objective was to identify potential therapeutic targets for serous EOC based on improved understanding of the molecular diversity of the disease. Ovarian tissues and matched peripheral blood samples were prospectively obtained from sequential patients undergoing planned gynecologic surgery at Cedars-Sinai Medical Center between 1989 and 2005. All patients underwent surgery and received adjuvant chemotherapy with a contemporaneous standard-of-care regimen. Ovarian tissue samples (n=172) were compared to a reference pool of 106 ovarian samples. Mixed reference includes normal, benign, borderline, and malignant samples.
Project description:The pooled sample method is used in epigenomic research and expression analysis and is a cost-effective screening approach for small amounts of DNA. Evaluation of the pooled sample method in epigenomic studies is performed using the Illumina Infinium Methylation 450K BeadChip array; however, subsequent reports on the updated 850K array are lacking. A previous study demonstrated that the methylation levels obtained from individual samples were accurately replicated using pooled samples but did not address epigenome-wide association study (EWAS) statistics. The DNA quantification method, which is important for the homogeneous mixing of DNA in the pooled sample method, has since become fluorescence-based, and additional factors need to be considered including the resolution of batch effects of microarray chips and the heterogeneity of the cellular proportions from which the DNA samples are derived. In this study, four pooled samples were created from 44 individual samples, and EWAS statistics for differentially methylated positions (DMPs) and regions (DMRs) were conducted for individual samples and compared with the statistics obtained from the pooled samples.
Project description:The transcriptional profiles of ovarian tissue from four laboratory mouse-inbred strains were obtained with NIA15K-cDNA microarrays and then correlated with the divergent spontaneous ovarian tumor rates and reproductive parameters reported for each strain. Four test samples and one reference sample - common reference design- dye swap - 5 to 6 replicates per sample - test samples pooled from 4-6 animals , 23 arrays
Project description:Comparative profiling of miRNA content within CD31+EVs comparing Ctrl and T2DM patients (5 vs 5 samples with each sample prepared from the pooled plasma of 4 subjects).
Project description:Homeobox genes generally encode transcription factors involved in regulating developmental processes. In the pineal gland, a brain structure devoted to nocturnal melatonin synthesis, a number of homeobox genes are also expressed postnatally; among these are the LIM homeobox 4 gene (Lhx4) and the brain‐specific homeobox gene (Bsx). As part of a larger study, we used of siRNA technology to knock down Lhx4 or Bsx expression in cultured adult rat pinealocytes. For RNAseq, nine barcoded libraries were pooled and sequenced on one Flow Cell of a HiSeq2500 (Illumina) in Rapid Run Mode yielding a total of 410 million 2∙x 100‐bp read‐pairs (average reads per sample: 45.6∙106 ± 3.3∙106 SEM). Analysis of control and siRNA‐treated pinealocytes revealed downstream target genes and insights into the role these homeobox genes play in the adult pineal gland. The two processed data file present siLhx4 vs siNT, or siBsx vs siNT.
Project description:Comparative genomic hybridization microarrays (array CGH or molecular karyotyping) for the detection of congenital chromosomal aberrations is the application of microarray technology that is coming fastest into routine clinical application. When using a two-channel microarray of genomic DNA probes for array CGH, the basic setup consists in hybridizing a patient sample against a normal reference sample and detecting copy number variations through the deviation of fluorescent signal intensity between patient and normal reference. Two major disadvantages of this setup are (1) the use of half of the resources to measure a (little informative) reference sample and (2) the possibility that deviating signals are caused by benign copy number variation in the ânormalâ reference instead of a patient aberration. We therefore propose a new experimental loop design that compares three patients in three hybridizations (Patient 1 vs. Patient 3, Patient 3 vs. Patient 2, and Patient 2 vs. Patient 1). We develop and compare two statistical methods (linear models of log ratios and mixed models of absolute measurements). In an analysis of data from 27 patients seen at our genetics center, this new setup together with the linear model analysis significantly overcomes the limitations of the classical setup. Furthermore, we observed that the linear models of the log-ratios had a higher signal-to-noise ratio than the mixed models of the absolute intensities. These improvements are important to guarantee a maximal efficiency of array CGH in a clinical setting and will therefore contribute to its quick adoption as a routine diagnostic tool. The method is implemented as a web application and is available at www.esat.kuleuven.be/loop. Keywords: comparative genomic hybridization The data set consists out of nine loop designs or 27 patients with mental retardation (MR) and multiple congenital anomalies (MCA). The patients were seen at our genetics center (Center for Human Genetics, U.Z.Leuven).
Project description:One µg of total RNA from either an individual rat or from a pooled sample was amplified and labeled with a fluorescent dye (either Cy3 or Cy5) using the Low RNA Input Linear Amplification Labeling kit (Agilent Technologies, Palo Alto, CA) following the manufacturer’s protocol. The amount and quality of the resulting fluorescently labeled cRNA was assessed using a Nanodrop ND-100 spectrophometer and an Agilent Bioanalyzer. Equal amounts of Cy3- or Cy5-labeled cRNA were hybridized to the Agilent Rat Oligo Microarray (Agilent Technologies, Inc., Palo Alto, CA) for 17 hrs, prior to washing and scanning. Data was extracted from the resulting images using Agilent’s Feature Extraction Software (Agilent Technologies, Inc., Palo Alto, CA). For day/night comparisons, two types of complementing hybridizations were performed: hepatic RNA from individual day rats was hybridized against a pool made up of RNA from 12 hour offset night rats, and RNA from individual night rats was hybridized against a pool made up of RNA from 12-hour offset day rats. Specifically, hepatic RNA samples from three individual day rats collected ten hours after light on (CT10) were hybridized against a pooled RNA sample composed of equal aliquots of RNA from the livers of six night rats collected ten hrs after lights off (CT22); and RNA samples from three individual night rats collected at CT22 were hybridized against a pooled RNA sample composed of equal aliquots of RNA from the livers of six day rats collected at CT10. This was replicated in a second study for a total of 24 hybridizations of 12 hour offset samples. For time of day comparisons, equal aliquots of RNA from the livers of six rats collected at each of four different times of the circadian day (CT4, CT10, C16 and CT22) were pooled. The two replicate studies thus resulted in 8 pools (two replicate pools/time point times four time points); each pool was hybridized against a Universal Rat Reference RNA Standard (Stratagene, La Jolla, CA). Keywords: time-course