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Open Access Publications from the University of California

Scholarly Works (2 results)

  • Thesis
  • Peer Reviewed
UC San Francisco Electronic Theses and Dissertations (2015)

The low efficacy of existing methods of treatment for late-stage melanoma has been attributed to the development of drug resistant cells. Following conventional treatments, enrichment of slowly cycling melanoma cells has been reported. Recently, a unique biological marker histone 3 K4 demethylase JARID1B was used to characterize slow-cycling cells within a rapidly proliferating population of melanoma cells. High JARID1B expression is almost exclusive to slow-cycling melanoma cells. This phenotype of cells has been shown to be temporarily distinct, dynamic, and necessary for continuous tumor growth. This study aims to seek metabolic changes between JARID1Bhigh subpopulations and bulk melanoma tumor cells. Targeting this subpopulation of drug resistant cells may improve the efficacy of existing treatments.

This project aims to identify and quantify metabolic differences by analyzing H NMR spectral data of cell extracts and culture media of slow-cycling JARID1Bhigh melanoma cells in comparison to highly proliferating bulk melanoma cells. We have demonstrated great improvement in acquiring consistent data for H NMR analysis over previous attempts. Our results show enhanced glucose and glutamine consumption, increased lactate/alanine ratios, and elevated concentrations of myo-inositol and choline derivatives in slow-cycling J/EGFPhigh subpopulations compared to highly proliferative tumor cells. These preliminary findings suggest heightened metabolic versatility in slow-cycling melanoma cells in accordance with recent revisions of cancer metabolism and may help understand the dynamic stem-ness of these seemingly quiescent cells.

    Cover page: Metabolic characterization of slowly cycling melanoma cells
    • Article
    • Peer Reviewed
    UC Davis Previously Published Works (2016)

    Objectives

    The aim of this study was to assess the feasibility of quantifying shoulder cartilage morphology and relaxometry in a clinically feasible scan time comparing different pulse sequences and assessing their reproducibility at 3 Tesla.

    Methods

    Three pulse sequences were compared for morphological assessments of shoulder cartilage thickness and volume (SPGR, MERGE, FIESTA), while a combined T1ρ-T2 sequence was optimized for relaxometry measurements. The shoulders of six healthy subjects were scanned twice with repositioning, and the cartilage was segmented and quantified. The degree of agreement between the three morphological sequences was assessed using Bland-Altman plots, while the morphological and relaxometry reproducibility were assessed with root-mean-square coefficients of variation (RMS-CVs) RESULTS: Bland-Altman plots indicated good levels of agreement between the morphological assessments of the three sequences. The reproducibility of morphological assessments yielded RMS-CVs between 4.0 and 17.7 %. All sequences correlated highly (R > 0.9) for morphologic assessments with no statistically significant differences. For relaxometry assessments of humeral cartilage, RMS-CVs of 6.4 and 10.6 % were found for T1ρ and T2, respectively.

    Conclusions

    The assessment of both cartilage morphology and relaxometry is feasible in the shoulder with SPGR, humeral head, and T1ρ being the more reproducible morphological sequence, anatomic region, and quantitative sequence, respectively.

    Key points

    • The thin cartilage morphology can be assessed in the shoulder in vivo. • Non-invasive biochemical assessment of shoulder cartilage is feasible in vivo using MRI.
      Cover page: Quantitative assessment of morphology, T1ρ, and T2 of shoulder cartilage using MRI
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