Biomedical subjects

Elliot Levy

Publications and source records attributed to Elliot Levy.

4 recordsLinked to original sources

PubMed2026

A stem-like chromatin program in small-cell lung cancer is associated with poor outcomes after chemoimmunotherapy.

Small-cell lung cancer (SCLC) is an aggressive malignancy with substantial tumor heterogeneity and limited clinically actionable biomarkers beyond established features such as liver metastases. We profile tumor-intrinsic chromatin accessibility in a patient-derived xenograft biobank and identify three recurrent chromatin programs: neuroendocrine, marked by ASCL1/NEUROD1 activity; immunogenic, marked by IRF-associated activity; and stem-like, marked by TEAD/OCT activity. These programs are reproduced at the cohort level across bulk and single-cell transcriptomic datasets comprising more than 800 tumors, including 300 extensive-stage samples. In patients treated with chemoimmunotherapy, the stem-like program is associated with inferior survival, including a median overall survival of 7.41 months versus 15.9 and 12.6 months for immunogenic and neuroendocrine groups, respectively. This association remains significant after adjustment for liver metastases, brain metastases, and elevated lactate dehydrogenase. These findings support a high-risk stem-like SCLC chromatin program for prospective biomarker refinement and therapeutic investigation.

ATAC-seq↗

PubMed2006

Electromagnetic tracking for abdominal interventions in computer aided surgery.

Electromagnetic tracking has great potential for assisting physicians in precision placement of instruments during minimally invasive interventions in the abdomen, since electromagnetic tracking is not limited by the line-of-sight restrictions of optical tracking. A new generation of electromagnetic tracking has recently become available, with sensors small enough to be included in the tips of instruments. To fully exploit the potential of this technology, our research group has been developing a computer aided, image-guided system that uses electromagnetic tracking for visualization of the internal anatomy during abdominal interventions. As registration is a critical component in developing an accurate image-guided system, we present three registration techniques: 1) enhanced paired-point registration (time-stamp match registration and dynamic registration); 2) orientation-based registration; and 3) needle shape-based registration. Respiration compensation is another important issue, particularly in the abdomen, where respiratory motion can make precise targeting difficult. To address this problem, we propose reference tracking and affine transformation methods. Finally, we present our prototype navigation system, which integrates the registration, segmentation, path-planning and navigation functions to provide real-time image guidance in the clinical environment. The methods presented here have been tested with a respiratory phantom specially designed by our group and in swine animal studies under approved protocols. Based on these tests, we conclude that our system can provide quick and accurate localization of tracked instruments in abdominal interventions, and that it offers a user-friendly display for the physician.

Abdomen↗

PubMed2002

Assessment of hepatic motion secondary to respiration for computer assisted interventions.

This article reviews the published efforts to characterize hepatic motion secondary to respiration, with the specific goal of defining the limitations and potential applications of image-guided systems in percutaneous liver interventions (computer assisted interventions). Hepatic motion and deformation due to respiration remain obstacles to applying stereotactic localization techniques to the liver. Respiratory-associated hepatic motion is complex. Nine studies using diagnostic imaging or modeling are reviewed, and their findings are tabulated herein. The significant variations in their findings are discussed, including cranio-caudal translation, anterior-posterior and lateral translation, movement secondary to tissue deformation, and motion with respect to surrounding tissue. Techniques for correcting for hepatic respiratory motion are then described, including gating techniques, modeling approaches, real-time liver tracking, and magnetic tracking technology.

Humans↗

PubMed2002

Delayed nephrologist referral and inadequate vascular access in patients with advanced chronic kidney failure.

We sought to determine whether late referral to a nephrologist in patients with chronic renal failure influences the adequacy of vascular access for hemodialysis. We analyzed data describing all health care encounters for all Medicare and Medicaid patients with end-stage renal failure in New Jersey between January 1991 and June 1996. Patients were required to have been diagnosed with renal disease at least 1 year prior to onset of hemodialysis. In the resulting cohort of 2,398 incident hemodialysis patients, 35% had their first nephrologist consultation < or =90 days prior to initiation of dialysis. After controlling for demographic characteristics, socio-economic status and underlying renal disease, we found that patients who were referred to a nephrologist >90 days prior to onset of hemodialysis were 38% more likely to have undergone predialysis vascular access surgery than those who were referred to a nephrologist < or =90 days before dialysis [OR: 1.38; 95% CI (1.15; 1.64)]. Similarly, patients referred late were 42% more likely to require central venous access for hemodialysis compared to those seen by a nephrologist early [OR: 1.42; 95% CI (1.17; 1.71)]. Inadequate development of vascular access for renal replacement therapy in patients with late nephrologist referral unnecessarily contributes to the burden of disease experienced by this vulnerable patient population.

Adult↗