Our purpose is to investigate the feasibility of imaging tumor metabolism in breast cancer patients using 13C magnetic resonance spectroscopic imaging (MRSI) of hyperpolarized 13C label exchange between injected [1-13C]pyruvate and the endogenous tumor lactate pool. Treatment-naïve breast cancer patients were recruited: four triple-negative grade 3 cancers; two invasive ductal carcinomas that were estrogen and progesterone receptor-positive (ER/PR+) and HER2/neu-negative (HER2−), one grade 2 and one grade 3; and one grade 2 ER/PR+ HER2− invasive lobular carcinoma (ILC). Dynamic 13C MRSI was performed following injection of hyperpolarized [1-13C]pyruvate. Expression of lactate dehydrogenase A (LDHA), which catalyzes 13C label exchange between pyruvate and lactate, hypoxia-inducible factor-1 (HIF1α), and the monocarboxylate transporters MCT1 and MCT4 were quantified using immunohistochemistry and RNA sequencing. We have demonstrated the feasibility and safety of hyperpolarized 13C MRI in early breast cancer. Both intertumoral and intratumoral heterogeneity of the hyperpolarized pyruvate and lactate signals were observed. The lactate-to-pyruvate signal ratio (LAC/PYR) ranged from 0.021 to 0.473 across the tumor subtypes (mean ± SD: 0.145 ± 0.164), and a lactate signal was observed in all of the grade 3 tumors. The LAC/PYR was significantly correlated with tumor volume (R = 0.903, P = 0.005) and MCT 1 (R = 0.85, P = 0.032) and HIF1α expression (R = 0.83, P = 0.043). Imaging of hyperpolarized [1-13C]pyruvate metabolism in breast cancer is feasible and demonstrated significant intertumoral and intratumoral metabolic heterogeneity, where lactate labeling correlated with MCT1 expression and hypoxia.

We present a theoretical framework that views learning as a process involving content learning (CL) and identity construction (IC). We view identities as lenses through which people make sense of, and position themselves, through stories and actions, and as lenses for understanding how they are positioned by others. As people become more (or less) central members of a disciplinary community (e.g., a science or mathematics classroom) and engage (or not) in various cultural practices, changes in identity and knowledge accompany changes in position and status. IC and CL share an important characteristic: they both involve meaning making. For IC, it is the development of reasoned, coordinated, coherent, and meaningful ways of seeing one’s self in relation to communities, and for CL, it centers on the development of disciplinary concepts, processes, tools, language, discourse, and norms within practices. Focusing on Black students in mathematics and science classrooms, we claim that three intersecting identities are particularly important: disciplinary identity (as doers of the discipline, i.e., mathematics and science), racial identity (emerging understandings of what it means to be Black), and academic identity (as participants in academic tasks and classroom practices). In this paper, we elaborate on the CLIC framework as a useful tool for understanding how Black students negotiate participation in, and come to see themselves as doers of science and mathematics in their school classrooms. We synthesize empirical findings from our research with younger and older students, as well as with parents and community members, to illustrate dimensions of this framework.

ABSTRACT:We focus on the concept of matter and explore how young children in urban schools bridge their spontaneous concepts and everyday experiences with scientific concepts introduced to them by children's literature information books and their teacher. The study shows how material artifacts used in a sorting activity became ideational tools-semiotic devices that promoted children's engagement with science and shaped the classroom discourse, thinking, and transactions. "Ambiguous" objects, such as a baggie with air, shaving cream, a baggie of salt that children were asked to sort, encouraged them to debate ideas about states of matter. Children used four ways of reasoning about states of matter: macroscopic properties, prototypes, everyday functions, and process of elimination. Furthermore, children's meaning making was intertwined with various socio-organizational aspects of inquiry-the ways in which children negotiated their roles within their group and in wholeclass sessions, how they worked with each other, how their ideas were heard by others. We discuss how curricular and instructional approaches that do not lead children to one specific answer or way of thinking become catalysts for the creation of discursive spaces, where children and teacher engage in meaning making in the midst of ambiguity and confusion.C 2007 Wiley Periodicals, Inc. Sci Ed 92: 65 -95, 2008