Learn about our physicians and nurse practitioners
Dr. Alex David
Dr. Mary Jo Shaver
Dr. Mary Jo Shaver is a graduate of Arkansas State University in Jonesboro, Arkansas, where she earned a B.S. degree in Chemistry in 1988. She then attended the University of Arkansas for Medical Sciences in Little Rock, Arkansas, where she completed her residency in the Department of Internal Medicine in 1996. She completed her Fellowship in the Division of Nephrology in 1998.
She was an instructor for the Division of Nephrology at UAMS until 1999, after which she became an Assistant Professor of Medicine for the Division of Nephrology at UAMS. She has served as the Director of Hemodialysis at UAMS, as well as the Program Director for the Nephrology Fellowship Program for the University of Arkansas for Medical Sciences and Central Arkansas Veterans Healthcare Department.
Dr. Shaver obtained her Board Certification in Internal Medicine in 1996 and her Board Certification in Nephrology in 2001. She is a member of the American Society of Internal Medicine, Arkansas Medical Society, American College of Physicians Counsel member Alpha Omega Alpha Honor Society, American Diabetes Association, American Society of Nephrology, National Kidney Foundation, and the American College of Physicians.
Dr. Shaver is married and has four children.
Dr. Robert Camferdam
Dr. Robert Camferdam is a graduate from the University of Arkansas at Little Rock where he earned a degree in Biology. He attended medical school at Ross University where he graduated summa cum laude. Dr. Camferdam completed his residency in Internal Medicine at the University of Arkansas for Medical Sciences in 2010 and then completed his fellowship training in Nephrology from UAMS in 2012, where he was co-chief fellow.
During his training he served as a research assistant at UAMS in the department of microbiology. At Ross University he worked as a supplemental instructor preparing college students for medicine careers. He was also the head teaching assistant during his time at Ross University.
Since leaving UAMS he continues to teach, working with the residency program in Internal Medicine at Unity Health.
He joined Nephrology Associates, PA in 2013 and is Board Certified in Internal Medicine and Nephrology. He enjoys spending time with his wife and two children. He enjoys golf, sailing, and traveling.
Dr. Gregory Mock
Dr. Mock graduated from South Dakota State University in Brookings, South Dakota with a B.S. degree in Biology. He attended the University of Minnesota School of Medicine in Minneapolis, Minnesota. He completed his residency in Internal Medicine in 1994 from William Beaumont Army Medical Center in El Paso, Texas and later completed his fellowship training in Nephrology in 1997 from Walter Reed Army Medical Center in Washington, D.C. Prior to joining Nephrology Associates, PA, he served as a nephrologist in Columbus, Mississippi. He has served as Chief Medical Resident/Staff at Internal Medicine Clinic in El Paso, Texas, Clinical Instructor of Department of Medicine for the F. Edward Hebert School of Medicine in Bethesda, Maryland, and Assistant Chief of Nephrology Services at William Beaumont Army Medical Center in El Paso, Texas.
Dr. Mock is certified by the American Board of Internal Medicine as well as American Board of Internal Medicine Nephrology Subspecialty Board. He is a member of the American Society of Nephrology and International Society of Nephrology.
Dr. Mock serves on the Board of Directors for Intra-American Restoration Corporation, and has previously served on the Board of Directors for Maple House Community Non-profit Organization.
Mary Ann Ross, RNP
Bio and photo coming soon!
PHYSICIANS
Dr. David graduated from Arkansas State University in 1985 with B.S. degrees in Biology and Med Tech. He then attended the University of Arkansas for Medical Sciences in Little Rock, Arkansas where he completed his medical residency in 1993. He became Board Certified in Internal Medicine in 1993. He completed his Nephrology Fellowship from 1993 to 1995.
Dr. David is our senior partner and has been with us since 1995. He is a member of the Arkansas Medical Society, Pulaski County Medical Society, and the Renal Physicians Association. He has served as the Ethics Committee Chairman at Baptist Memorial Medical Center, Medicine Chair at Baptist Memorial Medical Center, and has also served as a member on the Pharmacy and Therapeutics Committee. He is Chairman of the Board of the Little Rock Adventist Academy in Little Rock, Arkansas. He has been appointed by the Governor of Arkansas to the Arkansas Kidney Disease Commission, on which he has served since 2019.
Dr. David is married and has three children. His interests include music, tennis, photography, and golf.
ADVANCED PRACTICE PROVIDERS
Marissa Miller, PA-C
Marissa A. Miller is a Certified Physician Assistant (PA-C), specializing in Nephrology. The care she provides at Nephrology Associates, PA, is centered on those who have end stage renal disease (ESRD) requiring dialysis or those with Chronic Kidney Disease (CKD) nearing dialysis.
Marissa completed her Bachelor of Science in Clinical Exercise Science from The University of Texas at Arlington. She moved to Arkansas to attend PA school at the University of Arkansas for Medical Sciences, where she earned her Masters Degree in Physician Assistant Studies (MPAS). She is nationally certified through the National Commission on Certification of Physician Assistants (NCCPA) and is licensed through the Arkansas State Medical Board. Marissa was the first practicing PA in the state of Arkansas to join the Academy of Nephrology PAs.
In her free time she enjoys playing with her dogs, working out, and multiple kinds of fine arts and crafts.
Krystalyn Williams, DNP
Krystalyn Williams, DNP, APRN, FNP-C is a Nurse Practitioner with Nephrology Associates, P.A., dedicated to providing compassionate, evidence-based care for patients with acute and chronic kidney conditions. Originally from Conway, Arkansas, Krystalyn is committed to improving patient outcomes through personalized treatment plans, preventive care, and patient education.
She earned her Doctor of Nursing Practice from Arkansas State University and her Master of Science in Nursing – Family Nurse Practitioner from Walden University. She also holds a Bachelor of Science in Nursing from the University of Arkansas at Little Rock and an Associate of Applied Science in Nursing from Baptist Health College, where she served as Class Vice President. She is nationally certified through the American Academy of Nurse Practitioners (AANP) as a Family Nurse Practitioner and is licensed through the Arkansas State Board of Nursing.
