Current Trainees

  • Grace Samenuk, Ph.D.
  • Carmen Villalobos, Ph.D.
  • Christian Hunley, Ph.D.
  • Victoria Fischer, M.D.
  • Sivaram Neppala, M.D.
  • Janette Vazquez, Ph.D.

Grace Samenuk, Ph.D.                       (Mentor: K. Hargreaves)                    06/01/2021-present

Dr. Samenuk earned her PhD in Bioanalytical Chemistry from the University of Texas at San Antonio in 2021. Her thesis work involved developing novel analytical methods for furthering the biochemical understanding of invasive cattle fever ticks, and monitoring the bioavailability of various macrocyclic lactone-based drugs for antiparasitic interventions. Her work with the United States Department of Agriculture resulted in recommendations to the state veterinarians regarding the ongoing eradication of cattle fever ticks in Texas and the United States. Upon completion of her thesis work, she joined Dr. Ken Hargreaves lab as a postdoctoral researcher. Her current research focuses on both targeted and untargeted lipidomics, and how fatty acids influence pain and nociception. Her first aim is to further elucidate the role of polyunsaturated fatty acids, and their oxidized metabolites in pain and inflammation pathways. The targeted polyunsaturated fatty acids include essential omega-6 fatty acids and omega-3 fatty acids. Her second aim is to discover a lipid-based biomarker to predict pain threshold levels following an event such as surgery using a combination of preclinical animal models and clinical samples. Her research approach will utilize multidisciplinary techniques, including different forms of analytical mass spectrometry to identify and quantify the biologically relevant lipids.

Carmen Villalobos, Ph.D.                       (Mentor: Y. Gupta)                    02/01/2022-present

Dr. Villalobos is a proud New Mexican, having received her PhD in Biomedical Engineering at the University of New Mexico. Her thesis work focused on host-pathogen interactions at the cell surface where she specialized using stochastic optical resolution microscopy to investigate glucan structures on the surface of Candida albicans and lipid rafts on Giardia lamblia. Her training and experience have been diverse and range from the fabrication of microfluidic devices to determining gene rearrangements in pediatric cancers. Upon the completion of her graduate studies, Dr. Villalobos worked for the Defense Threat Reduction Agency as a biological scientist who deployed instrumentation to characterize aerosols during various types of field testing.

After moving to Texas with her family, Dr. Villalobos joined Dr. Yogesh Gupta’s laboratory as a postdoctoral research fellow. Her current research focuses on the BAF complex which plays a role in the organization of chromatin and associated factors so that regulatory DNA regions are accessible to transcription factors. In cancer cells, the assembly and recruitment of this complex is disrupted by deletions, mutations, and overexpression of subunits, resulting in aberrant BAF complexes. Studying the structure, mechanism, and specificity of critical activity factors will elucidate better approaches to stopping tumor-promoting functions of the aberrant BAF complex.

Christian Hunley, Ph.D.                       (Mentor: J Pugh)                       05/01/2022-present

Dr. Hunley earned his PhD in Physics from the University of Texas at San Antonio. He has peer revied work in applied physics where he studied electro-hydrodynamic (EHD) natural convection enhancement using power series expansions to analyze the average electric Nusselt number linked to low Prandtl number fluids. His work in nanophysics used classical solvation density functional theory, along with a surface complexation model, to investigate the effects of pH and nanoparticle size on the structural and electrostatic properties of an electrolyte solution surrounding a spherical silica oxide nanoparticle. For his dissertation he developed an innovative multi-scale approach capable of accounting for the atomistic details of a protein molecular structure, its biological environment, and their impact on electrical impulses in the form of ionic soliton waves. The final piece of this work focused on connecting a voltage gated ion channel to a traveling ionic wave packet along stiff, rod like actin filaments. This led to an interest in patch-clamp electrophysiology where he joined Dr. Jason Pugh’s lab to investigate cannabinoid signaling in the cerebellum by employing electrophysiology and two-photon imaging techniques. His primary research emphasis is to understand regulation of synaptic transmission and synaptic plasticity in the cerebellar circuit by using CB1 receptor activity.


Sivaram Neppala, M.D.                       (Mentor: R. DeFronzo)                    09/01/2022-present

Dr. Neppala graduated medical school from Katuri Medical College & Hospital in 2015 and completed her Internal Medicine residency at Texas Institute of Graduate Medical education & Research in June 2022.  His prior work mainly focused on Insulin resistance and Metabolic syndrome using the insulin clamp techniques with Radioisotopes which, to this day, remain the gold standard for measuring insulin resistance and insulin secretion. He also worked on Inhibition of Liver specific 11Beta-Hydroxysteroid Dehydrogenase Type 1 enzyme lower liver fat in NAFLD/NASH patients by using the same techniques. Dr. Neppala, participated in many projects and wrote several abstracts & manuscripts for medical journals, also participated in national and international conferences including American College of Physicians, Digestive Disease Week and European Society of Intensive Care Medicine and American College of Gastroenterology which enhancing my interest in this field further.

After moving to San Antonio, Dr. Neppala joined Dr. DeFronzo and Dr. Anderson group as a postdoctoral fellow. His current research focuses on the ketones, skeletal/cardiac muscle metabolism, and SGLT2 inhibitors. His clinical research protocol involves assessment of myocardial glucose and ketone metabolism and how they relate to cardiac function using the MRI and PET facilities at UT Heath Research Imaging Institute (RII).


Victoria Fischer, M.D .                      (Mentor: G. Toney)                    07/01/2022-present

I am an Active-Duty Army resident physician currently in my 5th-year of Neurological Surgery residency with a particular interest in cerebrovascular neurosurgery and with a career objective of research-based academic neurosurgery after my military obligation is complete.
My previous research experience is vast and began in undergrad in the clinical sciences investigating the neuroendocrine and neuropsychological effects of emotional stress on oxytocin. This was followed by my graduate level work in the pre-clinical sciences evaluating the interplay of semiconductor nanomaterials with cellular biological systems. Finally, over the last decade, my research has primarily returned to the clinical side studying various facets of neurosurgical pathologies, to include traumatic brain injury, pediatric cervical spine management, indications for cerebral ischemic stroke interventions, and sequelae of aneurysmal subarachnoid hemorrhage (aSAH) such as low-pressure hydrocephalus and delayed cerebral ischemia (DCI). Specifically, this last area of interest (aSAH) is of particular importance due to the poorly understood pathophysiology, grossly inadequate treatment options despite modern medical practices, and most significantly, the devastating impact on afflicted patients and families that I have personally witnessed first-hand.
Thus far, my residency training has enabled me to garner both surgical and non-surgical expertise invaluable to any preclinical or clinical research setting. Specifically, I have been able to hone procedural skills in both macrosurgical and more uniquely, microsurgical techniques. Moreover, success within the medical field necessitates vital, albeit non-technically-related, additional abilities such as those required for general medical management, leadership and teamwork promotion, effective communication, rapport building, technical writing resulting in peer-reviewed journal publications, and effective time-management strategies, to name a few. Additionally, my prior research endeavors have equipped me with a two-fold perspective of both the clinical and preclinical challenges which has fostered a unique understanding of the barriers, limitations, and possible areas for improvement within both research realms especially as they relate to closing the translational research gap. Furthermore, I have been able to utilize these skillsets yet again within the preclinical science domain during my most recent post-doctoral research fellowship appointment this academic year where I am studying the underlying sympathetic nervous system-related mechanisms for aSAH-induced vasospasm and DCI.
In summary, the skillsets I have cultivated throughout my research and residency experiences make me uniquely qualified to partake in this latest preclinical SAH project with an utmost chance for finding success: my leadership, critical thinking, time management, open mindedness, self-inspired motivation, microsurgical technical skills, and unique perspective all will serve to help facilitate my success in bridging the translational research gap from the preclinical to clinical realms both now and in my future career endeavors.


Janette Vazquez, Ph.D.                       (Mentor: C. Satizabal)                    11/01/2022-present


Dr. Vazquez earned her PhD in Biomedical Informatics from the University of Utah. During her time there, her work focused on the use of machine learning methods towards the analysis of medical science datasets. This included implementing various machine learning algorithms towards a diverse set of datasets ranging from self-reported social determinants for the analysis of clinical trial participation, the analysis of better predictions of engagement based on objective biometric measures, and the analysis of the effects of air pollution on COPD exacerbations utilizing mortality data and environmental air pollution data. She also worked on utilizing conformal prediction to assess the uncertainty of predictions in the machine learning analysis of the likelihood of an individual to participate in a clinical trial. Upon finishing her thesis work, she joined Dr. Satizabal’s lab as a postdoctoral research fellow where she will be working on analyzing data from the San Antonio Heart and Mind Study to identify midlife and late-life cardiovascular risk factors that contribute to disparities in cognitive aging, and how these modify genetic susceptibility to cognitive decline and Alzheimer’s disease.