2,964 research outputs found
Chemotaxonomic Analysis of the Venom Composition within the Ant Genus Strumigenys (Hymenoptera, Formicidae) in Taiwan
In Taiwan, the ant genus Strumigenys is represented by 13 species, nine of which being endemic to this island. Classic morphological taxonomy can be complex and may lead to equivoque identification within this group. To clarify subtle species assignments, we investigated the venom composition of five Strumigenys species, using SPME extraction and GC/MS analyses, and searched for a suitable chemical marker. Our results indicate that three out of the five species tested showed enough specificity in their chemical profiles to allow clear differentiation. However, the two remaining species could not be distinguished from each other on the basis of their venom composition. We further assessed the phylogenetic relationships between the five species, analyzing both morphological and chemical characters. Our clusters revealed congruency between some species associations and suggested that the analysis of venom composition may apply, at least partially, to Strumigenys chemosystematics. However, important discrepancies also appeared, signifying that selective pressures for chemical diversification have operated differentially during the speciation and dispersal processes within this genus inTaiwan
ETF, Stock Exchange Interconnection and the Looming Problems
The growing presence of the exchange-traded fund (ETF) has been a crucial development on the investment scene since its advent in the mid-1990s. The surge of popularity for ETFs, as well as the phenomenal pace of their growth, is a fact that can be observed everywhere in stock market trading. This paper examines the legal rules, the types and workings of ETFs, and their role in promoting stock exchange interconnection.The surge of ETFs does not come without its questions and concerns, however. With the analysis provided in this article, the potential problems, mostly notably the systemic risk showcased in the flash crash of August 24, 2015, and the inherent problem of derivative investing, are discussed. This paper concludes with a careful balancing of the benefits and perils presented by this innovative investment product
The Emergent Landscape of Detecting EGFR Mutations Using Circulating Tumor DNA in Lung Cancer.
The advances in targeted therapies for lung cancer are based on the evaluation of specific gene mutations especially the epidermal growth factor receptor (EGFR). The assays largely depend on the acquisition of tumor tissue via biopsy before the initiation of therapy or after the onset of acquired resistance. However, the limitations of tissue biopsy including tumor heterogeneity and insufficient tissues for molecular testing are impotent clinical obstacles for mutation analysis and lung cancer treatment. Due to the invasive procedure of tissue biopsy and the progressive development of drug-resistant EGFR mutations, the effective initial detection and continuous monitoring of EGFR mutations are still unmet requirements. Circulating tumor DNA (ctDNA) detection is a promising biomarker for noninvasive assessment of cancer burden. Recent advancement of sensitive techniques in detecting EGFR mutations using ctDNA enables a broad range of clinical applications, including early detection of disease, prediction of treatment responses, and disease progression. This review not only introduces the biology and clinical implementations of ctDNA but also includes the updating information of recent advancement of techniques for detecting EGFR mutation using ctDNA in lung cancer
Liquid biopsy genotyping in lung cancer: ready for clinical utility?
Liquid biopsy is a blood test that detects evidence of cancer cells or tumor DNA in the circulation. Despite complicated collection methods and the requirement for technique-dependent platforms, it has generated substantial interest due, in part, to its potential to detect driver oncogenes such as epidermal growth factor receptor (EGFR) mutants in lung cancer. This technology is advancing rapidly and is being incorporated into numerous EGFR tyrosine kinase inhibitor (EGFR-TKI) development programs. It appears ready for integration into clinical care. Recent studies have demonstrated that biological fluids such as saliva and urine can also be used for detecting EGFR mutant DNA through application other user-friendly techniques. This review focuses on the clinical application of liquid biopsies to lung cancer genotyping, including EGFR and other targets of genotype-directed therapy and compares multiple platforms used for liquid biopsy
Using LC-MS with de novo software to fully characterize the multiple methylations of lysine residues in a recombinant fragment of an outer membrane protein from a virulent strain of Rickettsia prowazekii
The outer membrane protein B (OmpB) of the typhus group rickettsiae is an immunodominant antigen and has been shown to provide protection against typhus in animal models. Consequently, OmpB is currently being considered as a potential rickettsiae vaccine candidate to be used in humans. The OmpB from virulent strains are heavily methylated while the attenuated strains are hypomethylated. Western blot analysis of partially digested OmpB revealed that one of the reactive fragments was located at the N-terminus (fragment A, aa 33–272). Recently, we have over expressed, purified, and chemically methylated the recombinant fragment A from Rickettsia prowazekii (Ap). The methylated Ap was thoroughly characterized by LC/MS/MS on the ProteomeX workstation. The protein sequence of Ap with and without methylation was 87.7% and 100% identified, respectively. This high sequence coverage enabled us to determine the sites and extent of methylation on the lysine residues in Ap. All the lysine residues except the C-terminus lysine were either mono-, di- or tri-methylated. In addition, carbamylation on the N-terminus glycine was identified using a combination of denovo sequencing (DeNovoX) and the pattern recognition (SALSA) program with accurate mass measurement. We demonstrated that the use of peptide identification (SEQUEST) in combination with SALSA and denovo sequencing provided a useful means to characterize the sequence and posttranslational modifications of given proteins
Association of Alzhemier\u27s Disease With Hepatitis C Among Patients With Bipolar Disorder
Associations of hepatitis C virus infection with Alzheimer’s disease have not been studied among higher risk, bipolar disorder patients. This population-based case-control study investigated the risks of hepatitis C virus infection among Alzheimer’s disease patients with bipolar disorder in the years preceding their Alzheimer’s disease diagnosis. We used 2000–2013 data from the Longitudinal Health Insurance Database in Taiwan. Among patients with bipolar disorder, 73 were diagnosed with Alzheimer’s disease (cases), who were compared with 365 individuals with bipolar disorder but without Alzheimer’s disease (randomly selected controls matched on sex, age, and index year with cases). Prior claims (before the diagnosis year/index year for controls) were screened for a diagnosis of hepatitis C virus infection. Conditional logistic regression models were used for analysis. We found that 23 (31.51%) and 60 (16.44%) patients with bipolar disease were identified with a hepatitis C diagnosis among those with and without Alzheimer’s disease, respectively. Compared to controls, patients with Alzheimer’s disease showed 2.31-fold (95% confidence interval = 1.28–4.16) increased risk of hepatitis C infections adjusted for demographics and socio-economic status. Findings suggest an association of Alzheimer’s disease with a preceding diagnosis of hepatitis C infection among patients with bipolar disorder. Findings may suggest a need for increased awareness of and appropriate surveillance for Alzheimer’s disease in patients with bipolar disorder diagnosed with hepatitis C infection
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