Recent studies have characterized the ABC half-transporter associated with mitoxantrone resistance in human cancer cell lines. Encoded by the ABCG2 gene, overexpression confers resistance to camptothecins, as well as to mitoxantrone. We developed four polyclonal antibodies against peptides corresponding to four different epitopes on the mitoxantrone resistance-associated protein, ABCG2. Three epitopes localized on the cytoplasmic region of ABCG2 gave rise to high-affinity antibodies, which were demonstrated to be specific for ABCG2. Western blot analysis of cells with high levels of ABCG2 showed a single major band of the expected 72-kDa molecular size of ABCG2 under denaturing conditions. Immunoblot analysis performed under non-reducing conditions and after treatment with cross-linking reagents demonstrated a molecular weight shift from 72 kDa to several bands of 180 kDa and higher molecular weight, suggesting detection of dimerization products of ABCG2. Evidence of N-linked glycosylation was also obtained using tunicamycin and N-glycosidase F. Finally, both by light, fluorescence and electron microscopic immunohistochemical staining, we demonstrate cytoplasmic and predominantly plasma membrane localization of ABCG2 in cell lines with high levels of expression. Plasma membrane staining was observed on the surface of the chorionic villi in placenta. These results support the hypothesis that ABCG2 is an ABC half-transporter that forms dimers in the plasma membrane, functioning as an ATP-dependent outward pump for substrate transport.
In the present study, Delton-sealed teeth had a lower risk than Fuji III-sealed teeth of developing caries, independent of the caries diagnostic method used.
Background: Magnetic resonance elastography (MRE) allows noninvasive assessment of intracranial tumor mechanics and may thus be predictive of intraoperative conditions. Variations in the use of technical terms complicate reading of current literature, and there is need of a review using consolidated nomenclature.
Objectives:We present an overview of current literature on MRE relating to human intracranial neoplasms using standardized nomenclature suggested by the MRE guidelines committee. We then discuss the implications of the findings, and suggest approaches for future research.
Method:We performed a systematic literature search in PubMed, Embase, and Web of Science; the articles were screened for relevance and then subjected to full text review. Technical terms were consolidated.
Results:We identified 12 studies on MRE in patients with intracranial tumors, including meningiomas, glial tumors including glioblastomas, vestibular schwannomas, hemangiopericytoma, central nervous system lymphoma, pituitary macroadenomas, and brain metastases. The studies had varying objectives that included prediction of intraoperative consistency, histological separation, prediction of adhesiveness, and exploration of the mechanobiology of tumor invasiveness and malignancy. The technical terms were translated using standardized nomenclature. The literature was highly heterogeneous in terms of image acquisition techniques, post-processing, and study design and was generally limited by small and variable cohorts.Conclusions: MRE shows potential in predicting tumor consistency, adhesion, and mechanical homogeneity. Furthermore, MRE provides insight into malignant tumor behavior and its relation to tissue mechanics. MRE is still at a preclinical stage, but technical advances, improved understanding of soft tissue rheological impact, and larger samples are likely to enable future clinical introduction.
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