Our Doctors

Christopher S Saunders, MD

Christopher S. Saunders, M.D.

Born and raised in Hartford, Connecticut, Dr. Saunders received his bachelor’s degree from Harvard University and medical degree from Case Western Reserve University in Cleveland, Ohio. He completed his internship, residency and his nephrology fellowship at The University Hospitals of Cleveland.

Dr. Saunders joined Ohio Kidney Consultants in 1987 where he currently serves as the Medical Director for the DaVita Dialysis Downtown Columbus unit as well as the medical director of inpatient dialysis at Grant Medical Center. Dr. Saunders also serves as the Chair of Nephrology at Riverside Methodist Hospital.

Dr. Saunders is married with 2 children and enjoys traveling, biking and golf in his spare time.

Kevin L. Schroeder, M.D.

Born in Columbus and raised in Findlay, Ohio, Kevin L. Schroeder MD received his bachelor’s degree from the University of Notre Dame and medical school degree from the Ohio State University College of Medicine. He completed his Internal Medicine Residency at Riverside Methodist Hospital and his Nephrology Fellowship at the University of Florida Shands Hospital in Gainesville, FL.

Dr. Schroeder served as the Program Director for the Transitional Year Residency Program at Riverside Methodist Hospital from 2005-2015. He served on the GMEC, MEC and MOT committees at Riverside during this time as well. Currently, he serves as the Medical Director for Inpatient Dialysis at Riverside, and is the Chair of the OhioHealth Nephrology Clinical Guidance Council. In addition, he serves as the Medical Director of Davita East and Davita Canal Winchester.

Dr. Schroeder has been an annual contributor to Conn’s Current Therapy, chapter on Acute Kidney Injury. Other areas of clinical interest include advanced hypertension management, chronic kidney disease and end stage renal failure. He has been a co-investigator in the Simplicity III and Reduce Hypertension trials at the OhioHealth Advanced Hypertension Clinic.

Dr. Schroeder and his wife, Anita, are blessed with four wonderful children: Oliver, Ana, Audrey and Sophia. He treasures spending time with his family and attending activities at Bishop Watterson High School and St. Agatha School.

Kevin Schroeder MD
Dr Naveen Singri MD

Naveen Singri, M.D.

Dr. Singri graduated with a bachelors in Economics from The Ohio State University in 1993 and received his medical degree from the University of Cincinnati. Dr. Singri joined Ohio Kidney Consultants in 2003.

Dr Singri provides care in all areas of kidney disease with special interest in chronic kidney disease and prevention of end stage renal disease. He rounds at Riverside Methodist Hospital and Grant Medical Center for inpatient consultations and sees outpatients at the Jasonway office and Grant satellite office. He is the past president of Ohio Kidney Consultants (2009-2015.) He is the medical director of Davita Hilliard Station dialysis center and Davita New Albany. He enjoys clinical teaching of medical students and residents with focus on clinical presentation, cost-effectiveness of diagnostic tests and bedside manner.

Dr Singri and his wife Vasanthi live in Dublin with their 4 children. Outside of the hospital, he enjoys playing basketball, coaching his childrens’ soccer teams and family vacations.

Elizabeth M. Rave, M.D.

Dr. Rave was born in Akron, Ohio. She completed her undergraduate degree in chemical engineering at the University of Toledo. After working for Goodyear for three years, she realized that medicine was her true calling. Dr. Rave attended medical school at the University of Toledo Medical School (formerly Medical College of Ohio, MCO) and went on to complete both her residency and nephrology fellowship training at The Ohio State University.

Dr. Rave has been with Ohio Kidney Consultants since 2005. She specializes in patients with chronic kidney disease, electrolytes, hypertension, and dialysis. She splits her clinical time seeing patients in the outpatient setting (either in the office or in dialysis centers throughout Columbus and the surrounding areas), and seeing acutely ill patients at the hospital. In addition to clinical responsibilities, she is heavily involved with patient care improvement though several hospital committees, including the OhioHealth Clinical Guidance Council. She has been a
co-investigator in the Simplicity III and Reduce Hypertension trials at the OhioHealth Advanced Hypertension Clinic.

Dr. Rave is married and has one son. In her free time she enjoys traveling, tennis, fitness and has completed several half marathons.

Elizabeth M Rave MD
Daniel J Roncone DO

Daniel J. Roncone, D.O.

Born and raised in Youngstown, Ohio, Dr. Roncone received his bachelor’s degree in biological sciences at The University of Cincinnati and his medical degree at The Ohio University Heritage College for Osteopathic Medicine. He completed his internship at Doctor’s Hosptial in Columbus, Ohio and his residency in Internal Medicine at Riverside Methodist Hospital. Dr. Roncone completed his fellowship in nephrology at The Ohio State University.

He joined Ohio Kidney Consultants in 2007. Dr. Roncone specializes in all areas of kidney disease with special interest in chronic kidney disease, electrolyte disturbances, hypertension and dialysis. He rounds at Riverside Methodist, Dublin Methodist and Doctors hospitals for inpatient consultations. His outpatient offices include our main Jasonway location as well as other sites on Georgesville road and in Grove City. He is the medical director of Davita Grove City and Davita West dialysis centers. He enjoys teaching medical students and residents as well as staffing the Hypertension Clinic at the OhioHealth Advanced Heart and Vascular Center.

Dr. Roncone is married with 4 children and in his spare time enjoys biking and playing golf.

Jerry W. Chellini, D.O.

Dr. Chellini was born and raised in Cincinnati, Ohio. He received his bachelor’s degree from the University of Cincinnati, and his medical degree from the Ohio University College of Osteopathic Medicine in Athens, Ohio. He completed his internship and residency at Doctor’s Hospital and his nephrology fellowship at The Ohio State University, both in Columbus, Ohio.

Dr Chellini joined Ohio Kidney Consultants in 2008 and currently serves as the Medical Director for the DaVita Dialysis Dublin unit. Dr. Chellini received additional specialized training in interventional nephrology. He performs these procedures at the Vascular Access Center of Central Ohio, where he also serves as the medical director.

In his spare time, Dr. Chellini enjoys spending time with his family and maintaining his physical fitness.

Jerry W Chellini DO
Tameem S Kaka MD

Tameem Kaka, M.D.

Dr. Tameem Kaka is a nephrologist in the Greater Columbus area and Delaware County, Ohio and has been in practice for several years. Dr. Kaka treats conditions affecting the kidneys such as renal failure, hypertension and chronic kidney disease. He serves as the Medical Director at US Renal Care – Delaware, DaVita Marion, and DaVita Marysville dialysis units. He is board certified by American Board of specialties including Internal Medicine and Nephrology. Dr. Kaka and his wife, Sejal have 2 kids and in his free time he enjoys camping, hiking, golf and tennis.

Ramesh Annadurai, M.D.

Dr. Annadurai was born in Chillicothe, Ohio but has lived in Columbus, Ohio most of his life. He completed his undergraduate degree in psychology at The Ohio State University and graduated Summa Cum Laude. Dr. Annadurai attended medical school at The Ohio State University as well. He continued on to complete his Internal Medicine residency at Riverside Methodist Hospital, followed by his nephrology fellowship at The Ohio State University.

Dr. Annadurai joined Ohio Kidney Consultants in July 2014 where specializes in treating patients with chronic kidney disease and end stage renal failure, requiring dialysis. In his spare time, he enjoys fitness, listening to music and spending time with his family.

Ramesh Annadurai MD
Ruba Nijmeh MD

Ruba Nijmeh, M.D.

Dr. Nijmeh was born in Amman, Jordan. She completed medical school at The University of Jordan in 1997. She completed her internship and residency at The University of Jordan in 2002, where she continued on as an instructor at the medical school. Dr. Nijmeh completed her Internal Medicine residency at NEOUCOM (Northeast Ohio Medical University College of Medicine) in 2010. Dr. Nijmeh is board certified for the American and Jordanian board of nephrology. She has worked in the private practice setting for over 5 years where she treats patients with chronic kidney disease as well as end stage renal disease. Dr. Nijmeh joined Ohio Kidney Consultants in July 2015 and she oversees dialysis patients at our Davita East, Davita Parkside, Davita Canal Winchester and Davita Mt. Vernon locations.

Christopher Valentine, M.D.

Born and raised in Toledo, Ohio, Dr. Valentine received his bachelor’s degree from Hillsdale College in Hillsdale, Michigan and medical degree from Case Western Reserve University. He completed his Internal Medicine residency at William Beaumont Hospital in Royal Oak, Michigan and his Nephrology Fellowship at The Ohio State University Medical Center in Columbus, Ohio.

Dr. Valentine worked in a private nephrology practice for two years prior to joining The Ohio State University where he worked for 11 years as a clinical Nephrologist and educator. He was the Training Program Director of the Nephrology Fellowship at OSU for 5 years.

Dr. Valentine has several awards including Best Doctors In America each year from 2012 – 2017 as well as being awarded fellowship in the American College of Physicians in 2011. He is board certified by the American Board of Internal Medicine in nephrology and internal medicine. He is also an American Society of Hypertension certified specialist in clinical hypertension.

Dr. Valentine and his wife reside in Dublin, Ohio with their three children. In his spare time he enjoys fishing and biking.

Christopher Valentine MD
Tani Olmos CNP

Marie Antoinette “Tani” S. Olmos, C.N.P.

Tani Olmos, CNP joined Ohio Kidney Consultants in 2010. She completed her undergraduate degree at Kenyon College, graduating with a Bachelor’s in Biology. Tani attended The Ohio State University where she earned her Registered Nurse and Masters Degree as a Family Nurse Practitioner. As an RN she practiced in Cardiac and Medical Intensive Care Units. Since becoming a CNP, she has dedicated her practice to the field of nephrology, especially to the CKD and ESRD populations.

Constance Nicastro-Bowman, C.N.P.

Constance Nicastro-Bowman joined Ohio Kidney Consultants in 2013. She graduated from The Ohio State University with a Bachelors in Nursing in 1998 and from Otterbein University with a Masters in Nursing in 2008. She practiced as a Nurse Practitioner in Cardiology at Riverside Methodist Hospital prior to her transition to Nephrology.

Connie is a member of the Ohio Association of Advanced Practice Nurses and the American Nephrology Nurses Association.

She provides care to both ESRD patients on hemodialysis at various Davita Dialysis centers in Central Ohio. In addition, she follows outpatients with chronic kidney disease at the Jasonway office location.

Connie and her husband reside in Dublin, Ohio with their 3 children, Bella, Emma and Nicolas. In her free time she enjoys running, social time with friends and spending time with her family.

Constance Nicastro Bowman CNP
Rebekah Amborski NP

Rebekah Amborski, C.N.P.

Bekah received her bachelor’s degree in nursing from The University of Toledo (formerly The Medical College of Ohio, MCO) in 2006. After graduation, she worked in the Intensive care unit and the surgical intensive care unit at Duke University Health Systems for several years. She moved back to Ohio, and worked at Doctor’s Hospital in the ICU setting and at Riverside Methodist Hospital in their cardiovascular and heart failure clinic. Eventually, she enrolled at Ohio University for her Master’s of nursing degree. She became a licensed Nurse Practitioner in 2015. Bekah joined Ohio Kidney Consultants in 2016, and is able to put her interest in high blood pressure and heart failure to good use working collaboratively with the RNA physicians in the care of acutely ill and hospitalized patients at one of our busiest hospitals. Bekah is married and stays very active with her three children.