Ronald W. Dudek, Ph.D.

Ronald Dudek

Professor and Director of Graduate Studies

office: Brody 7E-112
phone: 252-744-2863
email: dudekr@ecu.edu

B.S., St. John's University
Ph.D., University of Minnesota
Postdoctoral Fellow, Northwestern University


Research

My research efforts in the past have focused on the regeneration of pancreatic islets and glucose transport in skeletal muscle as indicated below. Although my research efforts have been fruitful and I believe have made some contribution to science, my present research efforts are limited to collaborative support on various projects for light and electron microscopy.

Regeneration of Pancreatic Islets:
Despite recent work on the insulin receptor and glucose transporter proteins suggesting a role of peripheral tissues (liver, skeletal muscle, adipose) in the etiology of diabetes, the disease may still be defined as a pathological state resulting from an absolute or relative lack of insulin. This concept directs attention to the fact that the number of properly functioning beta cells is of decisive importance for the development, course, and outcome of diabetes. It emphasizes the need for a far better understanding of how the beta cell mass originates. A possible approach to ameliorate diabetes is to regenerate the beta cell mass. It is important to make the distinction between islet growth/proliferation from pre-existing beta cells through a process of mitosis versus islet regeneration. Our definition of islet regeneration is the neoformation of islet tissue by a process that duplicates embryo genesis whereby tubules of endoderm differentiate into islet precursor cells. Presently, this area of research has received considerable attention with the possibility of directing embryonic stem cells to differentiate into pancreatic beta cells.

Glucose Transport in Skeletal Muscle:
We have investigated intact muscle tissue using ultrastructural immunocytochemistry and were the first to demonstrate GLUT4 (glucose transporter protein 4) ultrastructural immunolabeling in human skeletal muscle. We found that GLUT4 immunolabeling was localized specifically at the T-tubule (triad junction) and in an intracellular compartment, but no GLUT4 labeling was on the surface sarcolemmma. The fact that we found GLUT4 labeling on the triad but not on the sarcolemma seemed inconsistent with our previous report (using membrane fractionation) that translocation of glucose transporters to the "plasma membrane" occurred in response to insulin. However, we have measured nitrendipine binding (a marker for Ca++ channel of T-tubules) in "plasma membrane" isolated by the methods of both Grimditch et al. and Klip et al. and found substantial contamination by T-tubules. We then isolated sarcolemmal membranes and triad membranes by the method of Burdett et al. and demonstrated the presence of GLUT4 in the triad membranes but not in the sarcolemma. Based on these observations, we have proposed a novel hypothesis that insulin-stimulated glucose transport into the muscle cell might occur at the T-tubule. These experiments are no longer ongoing in my laboratory.

Other Activities:
A majority of my recent professorial efforts have been directed towards writing review books for the USMLE Step 1 exam. I have authored a number of books in various subjects and have begun work on an exciting systems-based series of books. Some of these books have been translated in foreign languages.


Selected Publications

Friedman, J.E., R.W. Dudek, D.S. Whitehead, D.L. Downes, W.R. Frisell, J.F. Caro, and G.L. Dohm. 1991. Immunolocalization of glucose transporter GLUT4 within human skeletal muscle. Diabetes 40: 150-154.

Dudek, R.W., I.E. Lawrence, R.S. Hill, and R.C. Johnson. 1991. Fetal mesenchyme induces islet cytodifferentiation in adult pancreatic ductal epithelium. Diabetes. 40: 1041-45.

Dohm, G.L., P.L. Dolan, W.R. Frisell, and R.W. Dudek. 1993. Role of transverse tubules in insulin stimulated muscle glucose transport. J. Cellular Biochemistry 52: 1-7.

Dudek, R.W., G.L. Dohm, G.D. Holman, S.W. Cushman, and C.M. Wilson. 1994. Glucose transport localization in rat skeletal muscle: Autoradiographic study using ATB-[2-3H]BMPA photolabel. FEBS Lett. 339: 205-208.

Chalovich, J.M., Y. Chen, R.W. Dudek, and H. Luo. 1995. Kinetics of binding of caldesmon to actin. J. Biol. Chem. 270: 9911-9916.

Sandstrom, P.A., D. Pardi, P.W. Tebby, R.W. Dudek, D.M. Terrian, T.M. Folks, and T.M. Buttke. 1995. Lipid hydroperoxide-induced apoptosis: Lack of inhibition by Bcl-2 overexpression. FEBS Lett. 365: 66-70.

Dohm, G.L. and R.W. Dudek. 1998. Role of transverse tubules (T-tubules) in muscle glucose transport. Adv. Exp. Med. Biol. 441: 27-34.

Dudek, R.W. and J. Fix. 1998. Board Review Series: Embryology, 2nd edition. Harwal Publishing Co., Malvern, PA.

Dudek, R.W. 1999. High-Yield Cell and Molecular Biology, 1st edition. Lippencott Williams & Wilkins, Philadelphia.

Dudek, R.W. 1999. High-Yield Cell and Molecular Biology, 1st edition: Chinese translation. Lippencott Williams & Wilkins, Philadelphia.

Patel D.M., R.W. Dudek, and M.D. Mannie. 2001. Intercellular exchange of class II MHC complexes: ultrastructural localization and functional presentation of adsorbed I-A/peptide complexes. Cell Immunol. 214: 21-34.

Dudek, R.W. 2001. High-Yield Embryology, 2nd edition. Lippencott Williams & Wilkins, Philadelphia.

Dudek, R.W. 2001. High-Yield Embryology, 2nd edition: Chinese translation. Lippencott Williams & Wilkins, Philadelphia.

Kim, K., A. Sirota, Y.-H. Chen, S. B. Jones, R. Dudek, G.W. Lanford, C. Thakore, and Q. Lu. 2002. Dendrite-like process formation and cytoskeletal remodeling regulated by δ-catenin expression. Exp. Cell Res. 275: 171-184.

Dudek, R.W. 2002. High-Yield Gross Anatomy, 2nd edition. Lippencott Williams & Wilkins, Philadelphia.

Dudek, R.W. 2002. Intisari Histologi, 1st edition: Indonesian translation. Lippincott Williams & Wilkins, Philadelphia.

Dudek, R.W. 2002. Biologie Cellulaire et Moleculaire, 1st edition: French translation. Lippincott Williams & Wilkins, Philadelphia.

Gantt K.R., R.G. Jain, R.W. Dudek, and P.H. Pekala. 2004. HuB localizes to polysomes and alters C/EBP-beta expression in 3T3-L1 adipocytes. Biochem. Biophys. Res. Commun. 313: 619-622.

Dudek, R.W. 2004. High-Yield Histology, 3rd edition. Lippincott Williams & Wilkins, Philadelphia.

Dudek, R.W. 2004. High-Yield Histology, 3rd edition: Chinese translation. Lippincott Williams & Wilkins, Philadelphia.

Dudek, R.W. 2006. High-Yield Lung, 1st edition. Lippincott Williams & Wilkins, Philadelphia.

Dudek, R.W. 2006. High-Yield Heart, 1st edition. Lippincott Williams & Wilkins, Philadelphia.

Dudek, R.W. 2006. High-Yield Kidney, 1st edition. Lippincott Williams & Wilkins, Philadelphia.


Former Students and Post-Doctoral Fellows

Name Title Location
William G. Masius, M.D., M.S. Physician Cabarrus Emergency Medicine Associates, Concord, NC

List of Faculty