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4,888 result(s) for "Mohan, K A"
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Spatial transcriptomics reveals discrete tumour microenvironments and autocrine loops within ovarian cancer subclones
High-grade serous ovarian carcinoma (HGSOC) is genetically unstable and characterised by the presence of subclones with distinct genotypes. Intratumoural heterogeneity is linked to recurrence, chemotherapy resistance, and poor prognosis. Here, we use spatial transcriptomics to identify HGSOC subclones and study their association with infiltrating cell populations. Visium spatial transcriptomics reveals multiple tumour subclones with different copy number alterations present within individual tumour sections. These subclones differentially express various ligands and receptors and are predicted to differentially associate with different stromal and immune cell populations. In one sample, CosMx single molecule imaging reveals subclones differentially associating with immune cell populations, fibroblasts, and endothelial cells. Cell-to-cell communication analysis identifies subclone-specific signalling to stromal and immune cells and multiple subclone-specific autocrine loops. Our study highlights the high degree of subclonal heterogeneity in HGSOC and suggests that subclone-specific ligand and receptor expression patterns likely modulate how HGSOC cells interact with their local microenvironment. Intratumoural heterogeneity in high-grade serous ovarian carcinoma (HGSOC) remains to be explored. Here, the authors perform spatial transcriptomics and reveal a high degree of subclonal heterogeneity in HGSOC.
The Three-Dimensional Morphology of Growing Dendrites
The processes controlling the morphology of dendrites have been of great interest to a wide range of communities, since they are examples of an out-of-equilibrium pattern forming system, there is a clear connection with battery failure processes and their morphology sets the properties of many metallic alloys. We determine the three-dimensional morphology of free growing metallic dendrites using a novel X-ray tomographic technique that improves the temporal resolution by more than an order of magnitude compared to conventional techniques. These measurements show that the growth morphology of metallic dendrites is surprisingly different from that seen in model systems, the morphology is not self-similar with distance back from the tip and that this morphology can have an unexpectedly strong influence on solute segregation in castings. These experiments also provide benchmark data that can be used to validate simulations of free dendritic growth.
Genetic analysis of heterogeneous subsets of circulating tumour cells from high grade serous ovarian carcinoma patients
Circulating tumour cells (CTCs) are heterogenous and contain genetic information from the tumour of origin. They bear specific intra- and extra-cellular protein markers aiding in their detection. However, since these markers may be shared with other rare cells in the blood, only genetic testing can confirm their malignancy. Herein, we analyse different CTC subsets using single cell whole genome DNA sequencing to validate their malignant origin. We randomly selected putative CTCs identified by immunostaining that were isolated from 4 patients with high grade serous ovarian cancer (HGSOC) and one with benign cystadenoma. We specifically targeted CTCs positive for epithelial (CK/EpCAM pos ), mesenchymal (vimentin pos ), and pseudoendothelial (CK/EpCAM pos plus CD31 pos ) markers. We isolated these cells and performed whole genome amplification (WGA) and low-pass whole-genome sequencing (LP-WGS) for analysis of copy number alterations (CNA). Of the CK/EpCAM pos cells analysed from the HGSOC patients, 2 of 3 cells showed diverse chromosomal CNAs. However, the 4 pseudoendothelial cells (CK/EpCAM pos plus CD31 pos ) observed in the HGSOC cases did not carry any CNA. Lastly, two of the clusters of vimentin positive cells sequenced from those found in the benign cystadenoma case had CNA. Despite the low number of cells analysed, our results underscore the importance of genetic analysis of putative CTCs to confirm their neoplastic origin. In particular, it highlights the presence of a population of CK/EpCAM pos cells that are not tumour cells in patients with HGSOC, which otherwise would be counted as CTCs.
Tuberculosis following the Use of Etanercept, a Tumor Necrosis Factor Inhibitor
Infliximab, a tumor necrosis factor (TNF) antagonist, is associated with tuberculosis (TB), but it is unknown whether this phenomenon is true of all TNF antagonists. We reviewed 25 cases of TB due to another TNF antagonist, etanercept, that were reported to the US Food and Drug Administration (FDA) between November 1998 and March 2002. Such cases are sometimes incomplete and are subject to underreporting. Fifteen patients received other immunosuppressive medications. The median interval between the receipt of the first dose of etanercept and the diagnosis of TB was 11.5 months. Thirteen patients had extrapulmonary TB at the time of diagnosis. Diagnosis was made on the basis of culture results for 12 patients, biopsy findings for 9, and sputum staining for 4. There were 2 deaths, 1 of which was directly attributed to TB. The estimated number of TB cases reported to the FDA for each person-year of treatment with etanercept (i.e., the \"reporting rate\") among patients with rheumatoid arthritis (RA) was ∼10 cases/100,000 patient-years of exposure. Clinicians considering etanercept for patients with RA should be alert to the possibility of the occurrence of TB, sometimes with an unusual extrapulmonary presentation. It is unclear whether etanercept therapy increases the risk of TB beyond the elevated TB rates already documented for patients with RA.
NGS-QCbox and Raspberry for Parallel, Automated and Rapid Quality Control Analysis of Large-Scale Next Generation Sequencing (Illumina) Data
Rapid popularity and adaptation of next generation sequencing (NGS) approaches have generated huge volumes of data. High throughput platforms like Illumina HiSeq produce terabytes of raw data that requires quick processing. Quality control of the data is an important component prior to the downstream analyses. To address these issues, we have developed a quality control pipeline, NGS-QCbox that scales up to process hundreds or thousands of samples. Raspberry is an in-house tool, developed in C language utilizing HTSlib (v1.2.1) (http://htslib.org), for computing read/base level statistics. It can be used as stand-alone application and can process both compressed and uncompressed FASTQ format files. NGS-QCbox integrates Raspberry with other open-source tools for alignment (Bowtie2), SNP calling (SAMtools) and other utilities (bedtools) towards analyzing raw NGS data at higher efficiency and in high-throughput manner. The pipeline implements batch processing of jobs using Bpipe (https://github.com/ssadedin/bpipe) in parallel and internally, a fine grained task parallelization utilizing OpenMP. It reports read and base statistics along with genome coverage and variants in a user friendly format. The pipeline developed presents a simple menu driven interface and can be used in either quick or complete mode. In addition, the pipeline in quick mode outperforms in speed against other similar existing QC pipeline/tools. The NGS-QCbox pipeline, Raspberry tool and associated scripts are made available at the URL https://github.com/CEG-ICRISAT/NGS-QCbox and https://github.com/ CEG-ICRISAT/Raspberry for rapid quality control analysis of large-scale next generation sequencing (Illumina) data.
Incidence of haematopoietic malignancies in US radiologic technologists
Background: There are limited data on risks of haematopoietic malignancies associated with protracted low-to-moderate dose radiation. Aims: To contribute the first incidence risk estimates for haematopoietic malignancies in relation to work history, procedures, practices, and protective measures in a large population of mostly female medical radiation workers. Methods: The investigators followed up 71 894 (77.9% female) US radiologic technologists, first certified during 1926–80, from completion of a baseline questionnaire (1983–89) to return of a second questionnaire (1994–98), diagnosis of a first cancer, death, or 31 August 1998 (731 306 person-years), whichever occurred first. Cox proportional hazards regression was used to compute risks. Results: Relative risks (RR) for leukaemias other than chronic lymphocytic leukaemia (non-CLL, 41 cases) were increased among technologists working five or more years before 1950 (RR = 6.6, 95% CI 1.0 to 41.9, based on seven cases) or holding patients 50 or more times for x ray examination (RR = 2.6, 95% CI 1.3 to 5.4). Risks of non-CLL leukaemias were not significantly related to the number of years subjects worked in more recent periods, the year or age first worked, the total years worked, specific procedures or equipment used, or personal radiotherapy. Working as a radiologic technologist was not significantly linked with risk of multiple myeloma (28 cases), non-Hodgkin’s lymphoma (118 cases), Hodgkin’s lymphoma (31 cases), or chronic lymphocytic leukaemia (23 cases). Conclusion: Similar to results for single acute dose and fractionated high dose radiation exposures, there was increased risk for non-CLL leukaemias decades after initial protracted radiation exposure that likely cumulated to low-to-moderate doses.
Multi-Marker Immunofluorescent Staining and PD-L1 Detection on Circulating Tumour Cells from Ovarian Cancer Patients
Detection of ovarian cancer (OC) circulating tumour cells (CTCs) is primarily based on targeting epithelial markers, thus failing to detect mesenchymal tumour cells. More importantly, the immune checkpoint inhibitor marker PD-L1 has not been demonstrated on CTCs from OC patients. An antibody staining protocol was developed and tested using SKOV-3 and OVCA432 OC cell lines. We targeted epithelial (cytokeratin (CK) and EpCAM), mesenchymal (vimentin), and OC-specific (PAX8) markers for detection of CTCs, and CD45/16 and CD31 were used for the exclusion of white blood and vascular endothelial cells, respectively. PD-L1 was used for CTC characterisation. CTCs were enriched using the Parsortix™ system from 16 OC patients. Results revealed the presence of CTCs in 10 (63%) cases. CTCs were heterogeneous, with 113/157 (72%) cells positive for CK/EpCAM (epithelial marker), 58/157 (37%) positive for vimentin (mesenchymal marker), and 17/157 (11%) for both (hybrid). PAX8 was only found in 11/157 (7%) CTCs. In addition, 62/157 (39%) CTCs were positive for PD-L1. Positivity for PD-L1 was significantly associated with the hybrid phenotype when compared with the epithelial (p = 0.007) and mesenchymal (p = 0.0009) expressing CTCs. Characterisation of CTC phenotypes in relation to clinical outcomes is needed to provide insight into the role that epithelial to mesenchymal plasticity plays in OC and its relationship with PD-L1.
Whole Genome Sequencing and Comparative Genomic Analysis Reveal Allelic Variations Unique to a Purple Colored Rice Landrace (Oryza sativa ssp. indica cv. Purpleputtu)
Purpleputtu ( ssp. cv. Purpleputtu) is a unique rice landrace from southern India that exhibits predominantly purple color. This study reports the underlying genetic complexity of the trait, associated domestication and de-domestication processes during its coevolution with present day cultivars. Along-with genome level allelic variations in the entire gene repertoire associated with the purple, red coloration of grain and other plant parts. Comparative genomic analysis using 'a panel of 108 rice lines' revealed a total of 3,200,951 variants including 67,774 unique variations in Purpleputtu (PP) genome. Multiple sequence alignment uncovered a 14 bp deletion in ( , a transcription factor of class) locus of PP, a key regulatory gene of anthocyanin biosynthetic pathway. Interestingly, this deletion in gene is a characteristic feature of the present-day white pericarped rice cultivars. Phylogenetic analysis of locus revealed a distinct clade showing proximity to the progenitor species and In addition, PP genome exhibits a well conserved 4.5 Mbp region on chromosome 5 that harbors several loci associated with domestication of rice. Further, PP showed 1,387 unique when SNPs compared to 3,023 lines of rice (SNP-Seek database). The results indicate that PP genome is rich in allelic diversity and can serve as an excellent resource for rice breeding for a variety of agronomically important traits such as disease resistance, enhanced nutritional values, stress tolerance, and protection from harmful UV-B rays.
An Integrated SNP Mining and Utilization (ISMU) Pipeline for Next Generation Sequencing Data
Open source single nucleotide polymorphism (SNP) discovery pipelines for next generation sequencing data commonly requires working knowledge of command line interface, massive computational resources and expertise which is a daunting task for biologists. Further, the SNP information generated may not be readily used for downstream processes such as genotyping. Hence, a comprehensive pipeline has been developed by integrating several open source next generation sequencing (NGS) tools along with a graphical user interface called Integrated SNP Mining and Utilization (ISMU) for SNP discovery and their utilization by developing genotyping assays. The pipeline features functionalities such as pre-processing of raw data, integration of open source alignment tools (Bowtie2, BWA, Maq, NovoAlign and SOAP2), SNP prediction (SAMtools/SOAPsnp/CNS2snp and CbCC) methods and interfaces for developing genotyping assays. The pipeline outputs a list of high quality SNPs between all pairwise combinations of genotypes analyzed, in addition to the reference genome/sequence. Visualization tools (Tablet and Flapjack) integrated into the pipeline enable inspection of the alignment and errors, if any. The pipeline also provides a confidence score or polymorphism information content value with flanking sequences for identified SNPs in standard format required for developing marker genotyping (KASP and Golden Gate) assays. The pipeline enables users to process a range of NGS datasets such as whole genome re-sequencing, restriction site associated DNA sequencing and transcriptome sequencing data at a fast speed. The pipeline is very useful for plant genetics and breeding community with no computational expertise in order to discover SNPs and utilize in genomics, genetics and breeding studies. The pipeline has been parallelized to process huge datasets of next generation sequencing. It has been developed in Java language and is available at http://hpc.icrisat.cgiar.org/ISMU as a standalone free software.
Routine Tumor Testing for Homologous Recombination Deficiency in Patients With High Grade Epithelial Ovarian Cancer at a Statewide Gynecological Cancer Service in Western Australia: An Observational Study
Background Poly‐ADP ribose polymerase inhibitors have been shown to improve progression‐free survival in patients with advanced high‐grade epithelial non‐mucinous ovarian cancers characterized by a deficiency in homologous recombination (HRD). Guidelines recommend all patients with advanced high‐grade epithelial ovarian cancer undergo genomic tumor testing for HRD. Our aim was to evaluate the first year of HRD testing at the statewide Western Australia Gynecologic Cancer Service to assess factors associated with obtaining a diagnostic HRD testing result. Methods Retrospective chart review. Results HRD testing was indicated in 84 patients, and ordered in 79, of which three had non‐diagnostic/inconclusive results, all due to insufficient tumor quantity. One patient had the sample collected using a 20‐gauge core biopsy needle under image guidance, one patient following interval debulking surgery, and one following primary debulking surgery. Of 76 patients with an HRD result, HRD was positive in 29 (38.2%). A somatic BRCA mutation was detected in six of these 29 patients (20.6%) and HRD positive, BRCAwt was detected in 23 of 29 patients (79.4%). All core biopsies with 16‐ and 18‐gauge needles had a diagnostic HRD result. Ten of 11 patients who were treated by neoadjuvant chemotherapy and whose biopsies were obtained at interval cytoreductive surgery had sufficient tumor tissue for testing and had a diagnostic HRD result. All ascitic/pleural fluid samples sent for HRD testing yielded diagnostic results. Conclusions Compliance with HRD testing was high, and only three of 79 (3.8%) patients had non‐diagnostic results.