Publications by authors named "G D Varma"

This work aims at exploiting the unique myelin specificity of the inhomogeneous magnetization transfer (ihMT) technique to characterize the recovery dynamics of active multiple sclerosis (MS) lesions. IhMT and three other myelin-sensitive techniques, conventional MT, T-weighted, and diffusion tensor imaging, were applied in a 12-month longitudinal study performed on relapsing-remitting MS patients. An exponential recovery model was used to fit the variations over time of the metrics derived from each MR technique within new active lesions.

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Background: Progression-free survival (PFS) is a crucial endpoint in cancer drug research. Clinician-confirmed cancer progression, namely real-world PFS (rwPFS) in unstructured text (ie, clinical notes), serves as a reasonable surrogate for real-world indicators in ascertaining progression endpoints. Response evaluation criteria in solid tumors (RECIST) is traditionally used in clinical trials using serial imaging evaluations but is impractical when working with real-world data.

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We carried out a single-cell multiomic analysis on a series of MYD88-mutated Waldenström macroglobulinemia (WM) patients and identified 2 distinct subtypes of disease, memory B-cell (MBC)-like and plasma cell (PC)-like, based on their expression of key lineage defining genes. Biologically, the subtypes are characterized by their variable capacity to differentiate fully toward a PC and exhibit unique transcriptomic, chromatin accessibility, and genomic profiles. The MBC-like subtype is unable to differentiate beyond the MBC stage, upregulates key MBC genes, and is characterized by upregulated B-cell receptor and phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling.

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Purpose: To develop methods for three-dimensional relaxometry and quantitative perfusion imaging using hyperpolarized [2-C]tertiary-butyl alcohol (TBA) in the rat brain under normal and ischemic conditions at 9.4 T. TBA is a freely diffusible tracer that readily traverses the blood-brain barrier, resulting in high tissue signal and long residence times.

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Human postmortem brain tissues provide an indispensable resource that is crucial for the understanding of neurological conditions, whether related to pathology subtype, burden, distribution or cell-type specificity. Pathology staging protocols provide guidelines for standardized sampling of brain tissues, but cover only a subset of regions affected by pathologies. Thus, to study how various neuropathologies and cell types in highly specialized circuit nodes correlate with functions specifically served by these nodes, additional protocols are necessary.

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