Browsing by Subject "Mutations"

Now showing 1 - 3 of 3
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    Mutation stability in primary and metastatic melanoma: what we know and what we don’t
    (F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2015) Varada, Sowmya; Mahalingam, Meera
    Despite the efficacy and success of targeted therapies, a significant number of patients with melanoma exhibit either intrinsic or acquired resistance to these drugs. Numerous mechanisms for the development of resistance have been postulated, but the precise reason for this is not known. In this review, we examine the incidence of mutations in select genes (BRAF, NRAS, C-KIT, and GNAQ) known to occur in melanoma, specifically in primary tumors and their paired metastases, to understand the significance of intratumoral heterogeneity by assessing how changes in mutation status alters the process of metastatic spread. Our data revealed a small yet consistent degree of discordance of mutations in the MAPK pathway commonly occurring in melanoma indicating that failed targeted therapy may be a consequence of this.
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    Mycoplasma bovis in Spanish Cattle Herds: Two Groups of Multiresistant Isolates Predominate, with One Remaining Susceptible to Fluoroquinolones
    (MDPI, 2020-07-07) Nouvel, Laurent-Xavier; Baranowski, Eric; Gómez-Martín, Ángel; Sánchez López, Antonio; Citti, Christine; de la Fe Rodríguez, Christian; García-Galán Pérez, Ana; Sanidad Animal
    Mycoplasma bovis is an important bovine pathogen causing pneumonia, mastitis, and arthritis and is responsible for major economic losses worldwide. In the absence of an efficient vaccine, control of M. bovis infections mainly relies on antimicrobial treatments, but resistance is reported in an increasing number of countries. To address the situation in Spain, M. bovis was searched in 436 samples collected from beef and dairy cattle (2016–2019) and 28% were positive. Single-locus typing using polC sequences further revealed that two subtypes ST2 and ST3, circulate in Spain both in beef and dairy cattle, regardless of the regions or the clinical signs. Monitoring of ST2 and ST3 isolates minimum inhibitory concentration (MIC) to a panel of antimicrobials revealed one major difference when using fluoroquinolones (FQL): ST2 is more susceptible than ST3. Accordingly, whole-genome sequencing (WGS) further identified mutations in the gyrA and parC regions, encoding quinolone resistance-determining regions (QRDR) only in ST3 isolates. This situation shows the capacity of ST3 to accumulate mutations in QRDR and might reflect the selective pressure imposed by the extensive use of these antimicrobials. MIC values and detection of mutations by WGS also showed that most Spanish isolates are resistant to macrolides, lincosamides, and tetracyclines. Valnemulin was the only one effective, at least in vitro, against both STs.
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    Role of isocitrate dehydrogenase 1/2 (IDH 1/2) gene mutations in human tumors
    (F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2015) Liu, Xiang; Ling, Zhi-Qiang
    In recent years, frequent isocitrate dehydrogenase 1/2 (IDH1/IDH2) gene mutations were found in a variety of tumors, which specifically alter arginine residues of catalytic active site in IDH1/IDH2 and confer new enzymatic function of directly catalyzing alpha-ketoglutarate (α-KG) to R-2-hydroxyglutarate (2- HG). 2-HG could competitively inhibit α-KG–dependent enzymes and might therefore contribute to tumorigenesis. In addition, mutation status of IDH1/IDH2 is closely related to the progress and prognosis of certain tumors. Thus IDH1/IDH2 is considered to be a promising biomarker for early diagnosis and prognosis and targeted therapy. In this study, the current research on IDH1/IDH2 mutation, especially the mechanisms and clinical characteristics related to tumor, are reviewed.