13C and 15N natural isotope abundance reflects breast cancer cell metabolism

13C and 15N natural isotope abundance reflects breast cancer cell metabolism

Breast cancer is the most common cancer in women worldwide. Despite the information provided by anatomopathological assessment and molecular markers (such as receptor expression ER, PR, HER2), breast cancer therapies and prognostics depend on the metabolic properties of tumor cells. However, metabolomics have not provided a robust and congruent biomarker yet, likely because individual metabolit...

Nicotine, acetanilide and urea multi-level 2H-, 13C- and 15N-abundance reference materials for continuous-flow isotope ratio mass spectrometry.

Accurate determinations of stable isotope ratios require a calibration using at least two reference materials with different isotopic compositions to anchor the isotopic scale and compensate for differences in machine slope. Ideally, the delta values of these reference materials should bracket the isotopic range of samples with unknown delta values. While the practice of analyzing two isotopica...

Comparative structural analysis of 1-methyladenosine, 7-methylguanosine, ethenoadenosine and their protonated salts IV: 1H, 13C, and 15N NMR studies at natural isotope abundance.

The 1H, 13C, and 15N NMR spectra of neutral and protonated forms of the nucleosides 1-methyladenosine (m1A), 7-methylguanosine (m7G) and ethenoadenosine (EA), as a model compound, have been analyzed in order to assign the site of protonation in m1A and m7G. Protonation of these nucleosides occurs in the pyrimidine ring of m1A and EA and in the imidazole ring of m7G, with the charge being distri...

13C NMR Metabolomics: Applications at Natural Abundance

High-precision optical measurements of 13C/12C isotope ratios in organic compounds at natural abundance.

A continuous-flow cavity ring-down spectroscopy (CRDS) system integrating a chromatographic separation technique, a catalytic combustor, and an isotopic (13)C/(12)C optical analyzer is described for the isotopic analysis of a mixture of organic compounds. A demonstration of its potential is made for the geochemically important class of short-chain hydrocarbons. The system proved to be linear ov...