Characterization of histone-related chemical modifications in formalin-fixed paraffin-embedded and fresh-frozen human pancreatic cancer xenografts using LC-MS/MS

2016 ◽  
Vol 97 (3) ◽  
pp. 279-288 ◽  
Author(s):  
Monika Bauden ◽  
Theresa Kristl ◽  
Roland Andersson ◽  
György Marko-Varga ◽  
Daniel Ansari
2020 ◽  
pp. mcp.TIR120.002216
Author(s):  
Daniel J. Geiszler ◽  
Andy T. Kong ◽  
Dmitry M Avtonomov ◽  
Fengchao Yu ◽  
Felipe da Veiga Leprevost ◽  
...  

Open searching has proven to be an effective strategy for identifying both known and unknown modifications in shotgun proteomics experiments. Rather than being limited to a small set of user-specified modifications, open searches identify peptides with any mass shift that may correspond to a single modification or a combination of several modifications. Here we present PTM-Shepherd, a bioinformatics tool that automates characterization of PTM profiles detected in open searches based on attributes such as amino acid localization, fragmentation spectra similarity, retention time shifts, and relative modification rates. PTM-Shepherd can also perform multi-experiment comparisons for studying changes in modification profiles, e.g. in data generated in different laboratories or under different conditions. We demonstrate how PTM-Shepherd improves the analysis of data from formalin-fixed paraffin-embedded samples, detects extreme underalkylation of cysteine in some datasets, discovers an artefactual modification introduced during peptide synthesis, and uncovers site-specific biases in sample preparation artifacts in a multi-center proteomics profiling study.


Author(s):  
Daniel J. Geiszler ◽  
Andy T. Kong ◽  
Dmitry M. Avtonomov ◽  
Fengchao Yu ◽  
Felipe V. Leprevost ◽  
...  

ABSTRACTOpen searching has proven to be an effective strategy for identifying both known and unknown modifications in shotgun proteomics experiments. Rather than being limited to a small set of user-specified modifications, open searches identify peptides with any mass shift that may correspond to a single modification or a combination of several modifications. Here we present PTM-Shepherd, a bioinformatics tool that automates characterization of PTM profiles detected in open searches based on attributes such as amino acid localization, fragmentation spectra similarity, retention time shifts, and relative modification rates. PTM-Shepherd can also perform multi-experiment comparisons for studying changes in modification profiles, e.g. in data generated in different laboratories or under different conditions. We demonstrate how PTM-Shepherd improves the analysis of data from formalin-fixed paraffin-embedded samples, detects extreme underalkylation of cysteine in some datasets, discovers an artefactual modification introduced during peptide synthesis, and uncovers site-specific biases in sample preparation artifacts in a multi-center proteomics profiling study.


2021 ◽  
pp. 104063872098688
Author(s):  
Andrea M. Camargo-Castañeda ◽  
Lauren W. Stranahan ◽  
John F. Edwards ◽  
Daniel G. Garcia-Gonzalez ◽  
Leonardo Roa ◽  
...  

In male dogs, Brucella canis frequently causes epididymitis, ultimately resulting in testicular atrophy and infertility. Although B. canis predominantly affects the epididymis, the misleading term “orchitis” is still commonly used by clinicians. Of additional concern, diagnosis in dogs remains challenging because of variable sensitivity and specificity of serologic assays and fluctuations in bacteremia levels in infected dogs, reducing the sensitivity of blood culture. We describe here the histologic lesions in the scrotal contents of 8 dogs suspected of being infected with B. canis and clinically diagnosed with orchitis. We explored the possibility of using immunohistochemistry (IHC) and real-time PCR (rtPCR) in formalin-fixed, paraffin-embedded (FFPE) tissues to detect the presence of B. canis. Epididymitis of variable chronicity was identified in all 8 dogs, with only 3 also exhibiting orchitis. Using rtPCR, the presence of B. canis was identified in 4 of 8 dogs, with 3 of these 4 dogs also positive by IHC. These results suggest that rtPCR and IHC are promising techniques that can be used in FFPE tissues to detect B. canis when other detection techniques are unavailable. Additionally, accurate recognition of epididymitis rather than orchitis in suspect cases could aid in accurate diagnosis.


1992 ◽  
Vol 4 (4) ◽  
pp. 393-399 ◽  
Author(s):  
Deborah M. Haines ◽  
Jane C. Kendall ◽  
Brad W. Remenda ◽  
Michelle M. Breker-Klassen ◽  
Edward G. Clark

Accurate identification of bovine Parainfluenza type 3 virus in bovine respiratory disease requires dependable, sensitive, and specific techniques for detection in affected animals. Immunohistochemical testing can be a rapid and reliable means of demonstration of virus in tissues from suspect cases; however, this procedure is dependent upon the quality of the antisera directed against the viral antigens. The production of rabbit polyclonal and murine monoclonal antibodies directed against bovine Parainfluenza type 3 virus and techniques for their use in fresh-frozen and formalin-fixed paraffin-embedded tissues in immunofluorescence and immunoperoxidase-based immunohistochemical tests are described.


2018 ◽  
Vol 143 (2) ◽  
pp. 183-189 ◽  
Author(s):  
Jing Li ◽  
Stephanie Gan ◽  
Alan Blair ◽  
Kyungji Min ◽  
Taraneh Rehage ◽  
...  

Context.— KRAS Mutation Test v2 is used for the qualitative detection and identification of 28 mutations in exons 2, 3, and 4 of the human KRAS gene. Objective.— To verify the performance of KRAS Mutation Test v2 and to evaluate its accuracy by correlation with a next-generation sequencing method on Illumina MiSeq. Design.— In this study, we used formalin-fixed, paraffin-embedded tissue and plasma specimens from non–small cell lung cancer, colorectal cancer, and pancreatic cancer patients. Results of specificity, precision, analytical sensitivity, and accuracy as compared with a MiSeq method are reported. Results.— The KRAS Mutation Test v2 demonstrated exquisite sensitivity and specificity and broad coverage of KRAS mutations. Precision was 100% (108 of 108) across all samples, operators, and instruments for formalin-fixed, paraffin-embedded tissue and 99.8% (615 of 616) for plasma. Analytical sensitivity was high with detection of 1% mutant sequence in formalin-fixed, paraffin-embedded tissue samples and as low as 25 mutant sequence copies/mL for plasma samples. The test also showed high overall concordance for formalin-fixed, paraffin-embedded tumor tissue as well as for plasma specimens when compared with MiSeq sequencing results. Conclusions.— The KRAS Mutation Test v2 is a highly robust, reproducible, and sensitive test for the qualitative detection of 28 mutations in exons 2, 3, and 4 of the KRAS gene in both solid (tissue) and liquid (plasma) biopsies from colorectal cancer, non–small cell lung cancer, and pancreatic cancer, and is a convenient option for KRAS mutation testing.


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