Anesthesiology and Surgery
Research Opportunities
Research Mentors:
Department of Anesthesiology
Efforts in our laboratory are directed towards determining how anesthetic agents interfere with the coupling of excitation or stimulation to subsequent cell processes such as contraction or secretion. Such studies inevitably provide additional insights into the cellular processes which are responsible for these various cell behaviors. Ongoing work has been directed toward determining how the volatile anesthetics alter calcium channel currents in a variety of cells: ventricular myocytes; bovine adrenal chromaffin cells; dorsal root ganglion cells; cultured cerebellar granule cells; as well as Xenopus oocytes expressing a variety of cloned voltage gated calcium channels. We are also exploring anesthetic effects on a variety of potassium channels which influence cell excitability and calcium entry, effects that appear to provide preconditioning and protection in a variety of tissues.
In addition, we are examining effects of anesthetics on calcium mediated release of glutamate from synaptosome and cultured granule cells. We have previously examined how anesthetics alter calcium uptake and release by the sarcoplasmic reticulum isolated from cardiac tissue, examining the activity of the Ca-ATPase activity and calcium release channels (ryanodine receptors). Techniques and preparations used in the laboratory involve: patch clamping of isolated cells (single channel and whole cell); contractile and electrophysiologic study of papillary muscles; intracellular calcium measurements employing fura-2, both in cell suspensions as well as in isolated cells; and measurement of release of neurotransmitters employing enzyme coupled and electrochemical detection methods; calcium uptake and release and ryanodine binding by isolated sarcoplasmic reticulum.
Dr. Julianne J. Sando: Signal Transduction through Protein Kinase C
The major interest of my laboratory is in activation of Protein Kinase C (PKC) and its role in cellular signal transduction. PKC is a family of related protein kinases that are activated by association with cell membranes. Most cells have several members of this enzyme class and alterations in isozyme expression or activation have been found in a number of diseases including some cancers, some endocrine disorders like diabetes, some neurological disorders and some cardiovascular diseases. Pharmaceutical companies are trying to identify drugs that target individual isozymes for use in some of these diseases. We are trying to understand the structure and activation of the enzymes and the role of individual isozymes in specific cellular processes to help further this progress.
Properties of membrane lipids that activate PKC are studied using biochemical and biophysical techniques. With Drs. Zuo, Kamatchi, and Lynch (Anesthesiology), we are testing the hypothesis that lipid-soluble mediators such as anesthetics alter membrane properties that affect PKC activation, leading to phosphorylation of ion channels involved in pain and consciousness pathways. With Drs. Steers and Tuttle (Urology) we have pursued the involvement of PKC in transducing physical stimuli such as stretch or pressure that occur in the urinary tract or the vasculature. Structural analysis of PKC is conducted in collaboration with Drs. Grisham and Cafiso (Chemistry) using NMR and EPR, with Dr. Kretsinger (Biology) via generation of 2D crystals on monolayers, and with Dr. Shao (Physiology) using Atomic Force Microscopy.
Department of Surgery
His research interests include alterations of pulmonary physiology in adults and children, in health and disease. His clinical interests in lung transplantation are accompanied by his basic science investigations. Such investigations are carried out in four experimental models. The first is a murine model of left lung ischemia and reperfusion, allowing one to study the effects of reperfusion in strains of mice where gene-targeting will be used to generate animals that lack the inducible nitric oxide synthase (iNOS) and endogenous nitric oxide synthase (eNOS) genes. The second model is an isolated vascular ring preparation with which endothelial function can be quantified. The third model is an isolated, blood perfused, ventilated rabbit lung model in which the severity of lung injury can be accurately quantified during reperfusion and the functional consequences of interventions can be assessed. Such a model allows functional evaluation of the entire intact pulmonary vascular bed. The fourth is a porcine left lung transplant model thereby allowing us to further interpret our findings in a large animal model. Using these models, investigations into the following areas of his research interests are carried out:
Reperfusion injury of the lung following transplantation remains a concern and much of his work is aimed at improving lung preservation and minimizing ischemia-reperfusion injury. Efforts have focused on pulmonary surfactant replacement therapy, anti-leukocyte therapies (anti-ICAM and neutrophil protease inhibitors), and inhaled nitric oxide therapyCurrent pulmonary preservation strategies fail to provide reliable long-term protection of the graft. Clinical transplantation is limited by acceptable cold ischemic periods of 6-8 hours. Dr. Kron continues investigations into preservation solution composition and is exploring diversified preservation strategies tailored to meet the clinical situation in which the graft is to function. Efforts into using low-potassium extracellular solutions in settings where a degree of pulmonary hypertension is anticipated to persist following implantation have proved efficacious. Similar strategies mimicking common clinical situations are explored using the experimental models, as he feels one standardized preservation technique for all clinical circumstances is archaic. The use of mature lobar transplants may provide donors for immature recipients; however, the long-term results using this type of graft remain unknown.
Dr. Kron is also interested in the effects of denervation, inherent to the transplant procedure, on growth, development, and long-term function of transplanted immature and mature lungs. Correlations between growth and function, both at the cellular and organismal level are carried out. Current pulmonary donor availability is critically short. In an effort to expand the number of usable organs, Dr. Kron continues investigations into the use of lungs harvested from non-heart-beating donors. Inherent to this method of organ procurement is a mandatory period of warm ischemia with resultant injury to the graft. His efforts are defining an acceptable limit for this warm ischemic period. Techniques to improve the post-implantation function of lungs harvested from donors who expire from cardiopulmonary criteria rather than brain death criteria are also being explored. back to top