The O’Rourke Lab uses an integrated approach to study the biophysics and physiology of cardiac cells in normal and diseased states. Research in our lab has incorporated mitochondrial energetics, Ca2+ dynamics, and electrophysiology to provide tools for studying how defective function of one component of the cell can lead to catastrophic effects on whole cell and whole organ function. By understanding the links between Ca2+, electrical excitability and energy production, we hope to understand the cellular basis of cardiac arrhythmias, ischemia-reperfusion injury, and sudden death. We use state-of-the-art techniques, including single-channel and whole-cell patch clamp, microfluorimetry, conventional and two-photon fluorescence imaging, and molecular biology to study the structure and function of single proteins to the intact muscle. Experimental results are compared with simulations of computational models in order to understand the findings in the context of the system as a whole. Ongoing studies in our lab are focused on identifying the specific molecular targets modified by oxidative or ischemic stress and how they affect mitochondrial and whole heart function. The motivation for all of the work is to understand • how the molecular details of the heart cell work together to maintain function and • how the synchronization of the parts can go wrong Rational strategies can then be devised to correct dysfunction during the progression of disease through a comprehensive understanding of basic mechanisms. Brian O’Rourke, PhD, is a professor in the Division of Cardiology and Vice Chair of Basic and Translational Research, Department of Medicine, at the Johns Hopkins University.

The Hey-Kyoung Lee Lab is interested in exploring the cellular and molecular changes that happen at synapses to allow memory storage. We use various techniques, including electrophysiological recording, biochemical and molecular analysis, and imaging, to understand the cellular and molecular changes that happen during synaptic plasticity. Currently, we are examining the molecular and cellular mechanisms of global homeostatic synaptic plasticity using sensory cortices as model systems. In particular, we found that loss of vision elicits global changes in excitatory synaptic transmission in the primary visual cortex. Vision loss also triggers specific synaptic changes in other primary sensory cortices, which we postulate underlies sensory compensation in the blind. One of our main research goals is to understand the mechanisms underlying such cross-modal synaptic plasticity. We are also interested in elucidating the events that occur in diseased brains. In collaboration with other researchers, we are analyzing various mouse models of Alzheimer's disease, especially focusing on the possible alterations in synaptic plasticity mechanisms.

The Penet lab is within the Division of Cancer Imaging Research in the Department of Radiology and Radiological Science. The lab research focuses on using multimodal imaging techniques to better understand the microenvironment and improve cancer early detection, especially in ovarian cancer. By combining MRI, MRS and optical imaging, we are studying the tumor microenvironment to understand the role of hypoxia, tumor vascularization, macromolecular transport and tumor metabolism in tumor progression, metastasis and ascites formation in orthotopic models of cancer. We also are studying the role of tumor-associated macrophages in tumor progression.

Research in the Mary Beth Brady Lab focuses primarily on topics within the fields of anesthesiology, imaging and cardiology. Our work has explored transesophageal echocardiography simulation, echocardiography, cardiac and vascular-thoracic anesthesiology, and other areas within critical care medicine. A recent study involved obtaining 3-D images of the heart, which were then used to build computer programs to help cardiac surgeons improve their treatment of heart defects.

The Pathak lab is within the Division of Cancer Imaging Research in the Department of Radiology and Radiological Science. We develop novel imaging methods, computational models and visualization tools to ‘make visible’ critical aspects of cancer, stroke and neurobiology. Our research broadly encompasses the following areas: Functional and Molecular Imaging; Clinical Biomarker Development; Image-based Systems Biology and Visualization and Computational Tools. We are dedicated to mentoring the next generation of imagers, biomedical engineers and visualizers. Additional information can be found at www.pathaklab.org or by emailing Dr. Pathak.

The Shanthini Sockanathan Laboratory uses the developing spinal cord as our major paradigm to define the mechanisms that maintain an undifferentiated progenitor state and the molecular pathways that trigger their differentiation into neurons and glia. The major focus of the lab is the study of a new family of six-transmembrane proteins (6-TM GDEs) that play key roles in regulating neuronal and glial differentiation in the spinal cord. We recently discovered that the 6-TM GDEs release GPI-anchored proteins from the cell surface through cleavage of the GPI-anchor. This discovery identifies 6-TM GDEs as the first vertebrate membrane bound GPI-cleaving enzymes that work at the cell surface to regulate GPI-anchored protein function. Current work in the lab involves defining how the 6-TM GDEs regulate cellular signaling events that control neuronal and glial differentiation and function, with a major focus on how GDE dysfunction relates to the onset and progression of disease. To solve these questions, we use an integrated approach that includes in vivo models, imaging, molecular biology, biochemistry, developmental biology, genetics and behavior.

The Sujatha Kannan Lab works to develop therapeutic strategies for preventing perinatal brain injuries from occurring during development. We use a unique combination of nanotechnology, animal model development and in vivo imaging to better understand the mechanism and progression of cellular and metabolic conditions that lead to perinatal brain injury, with a focus on autism and cerebral palsy.

The main research goals of my laboratory are: (1) to identify and study the biology of novel cancer selective targets whose enzymatic function can be exploited for therapeutic and diagnostic purposes; (2) to develop methods to target novel agents for activiation by these cancer selective targets while avoiding or minimizing systemic toxicity; (3) to develop novel agents for imaging cancer sites at earliest stages. To accomplish these objectives the lab has originally focused on the development of prodrugs or protoxins that are inactive when given systemically via the blood and only become activated by tumor or tissue specific proteases present within sites of tumor. Using this approach, we are developing therapies targeted for activation by the serine proteases prostate-specific antigen (PSA), human glandular kallikrein 2 (hK2) and fibroblast activation protein (FAP) as well as the membrane carboxypeptidase prostate-specific membrane antigen (PSMA). One such approach developed in the lab consists of a potent bacterial protoxin that we have reengineered to be selectively activated by PSA within the Prostate. This PSA-activated toxin is currently being tested clinically as treatment for men with recurrent prostate cancer following radiation therapy. In a related approach, a novel peptide-cytotoxin prodrug candidate that is activated by PSMA has been identified and is this prodrug candidate is now entering early phase clinical development. In addition, we have also identified a series of potent inhibitors of PSA that are now under study as drug targeting and imaging agents to be used in the treatment and detection of prostate cancer.

Dr. Hua's research has centered on the development of novel MRI technologies for in vivo functional and physiological imaging in the brain, and the application of such methods for studies in healthy and diseased brains. These include the development of human and animal MRI methods to measure functional brain activities, cerebral perfusion and oxygen metabolism at high (3 Tesla) and ultra-high (7 Tesla and above) magnetic fields. He is particularly interested in novel MRI approaches to image small blood and lymphatic vessels in the brain. Collaborating with clinical investigators, these techniques have been applied 1) to detect functional, vascular and metabolic abnormalities in the brain in neurodegenerative diseases such as Huntingdon's disease (HD), Parkinson's disease (PD), Alzheimer's disease (AD) and mental disorders such as schizophrenia; and 2) to map brain functions and cerebrovascular reactivity for presurgical planning in patients with vascular malformations, brain tumors and epilepsy.

How do we see, hear, and think? More specifically, how can we study living people to understand how the brain sees, hears, and thinks? Recently, magnetic resonance imaging (MRI), a powerful anatomical imaging technique widely used for clinical diagnosis, was further developed into a tool for probing brain function. By sensitizing magnetic resonance images to the changes in blood oxygenation that occur when regions of the brain are highly active, we can make ""movies"" that reveal the brain at work. Dr. Pekar works on the development and application of this MRI technology. Dr. Pekar is a biophysicist who uses a variety of magnetic resonance techniques to study brain physiology and function. Dr. Pekar serves as Manager of the F.M. Kirby Research Center for Functional Brain Imaging, a research resource where imaging scientists and neuroscientists collaborate to study brain function using unique state-of-the-art techniques in a safe comfortable environment, to further develop such techniques, and to provide training and education. Dr. Pekar works with center staff to serve the center's users and to keep the center on the leading edge of technology.