Current Renal Fellows

First-Year Fellows 

Peter Dock, DOdock

Hometown: Duluth, Minnesota

Medical School: A.T. Still University KCOM

Residency: Hennepin County Medical Center

Research/Clinical Interests: Glomerulonephritis, transplant medicine, home dialysis

Hobbies: I enjoy reading, finding new restaurants, hiking, mountain biking, and snowboarding

Why did you choose the University of Colorado? I chose the University of Colorado because the focus on education is at the core of the program. Also, the opportunity to explore a wide variety of clinical avenues and for the research experiences available for fellows. Also it never hurts to have mountains to explore in your backyard!


Matt Johnson, MD

Hometown: Augusta, GA

Medical School: Quinnipiac University

Residency: Rush University

Research/Clinical Interests: Transplant, medical education, health disparities

Hobbies: Piano, cats, knitting, trying new food, whiskey, making references to Derry Girls in every conversation, Beat Saber! 

Why did you choose the University of Colorado? I was impressed with the emphasis on the curriculum being centered and flexible around the fellows’ interests, career goals, and wellness. I was also drawn to the wide range of clinical experience with the combination of three different hospital types and a large transplant program, as well as a lot of opportunity to get involved in medical education. 


Marko KarakadzeKarakadze

Hometown: Miami, FL


Medical School: Ponce Health Sciences University


Residency: University of Texas Houston (UTH Houston)


Research/Clinical Interests: Vascular access, Home dialysis modalities, AKI


Hobbies: Playing with my dog (Henley, named after Loop of Henle), watching sports, video games, Skiing/snowboarding, playing pickle ball, spearfishing, Netflix


Why did you choose the University of Colorado? Its history of contribution to the world of nephrology as well as the sense of joy I felt from communicating with current fellows. Given that plus its location, it was a no-brainer to rank them #1. 


Mona Panda, MDPanda

Hometown: Chadds Ford, Pennsylvania


Medical School: American University of the Caribbean, Sint Maarten


Residency: Mercy Catholic Medical Center, Darby, Pennsylvania


Research/Clinical Interests: I have a wide variety of clinical interests within Nephrology including Glomerular diseases/ANCA vasculitis, Renal Nutrition, Hemo- and Peritoneal Dialysis, CRRT, TPE, Mineral and Bone disorders and anemia management in CKD/ESRD, Diabetic nephropathy, PKD, Kidney Stones, and Nephrology Medical Education.


Hobbies: I enjoy drawing and painting in all mediums, reading, playing piano, traveling, and exploring with my yorkie, Sophie. I also enjoy scuba diving including diving with sharks, exploring coral reefs and shipwrecks, and cavern diving.


Why did you choose the University of Colorado? I chose University of Colorado because the faculty's dedication to fellow education and wellness, personalized career development/mentoring, flexibility in training tracks, strong history of career placement in academics, along with clinical and patient diversity across three hospitals. Also, Denver is super dog friendly and provides so many outdoor activities I can explore with Sophie.

Marco Ramos Castaneda, MD
Marco Ramos Castaneda

Hometown: Aguascalientes, Mexico

Medical School: TEscuela de Medicina Ignacio Santos, Tec de Monterrey 

Residency: Harlem Hospital Center, New York, NY

Research/Clinical Interests: Transplant nephrology, AKI, health disparities, glomerulonephritis 

Hobbies:  Music (guitar, piano, drums), playing tennis and golf, training and playing chess, hiking and recent skier, cinephile  

Why did you choose the University of Colorado? First, due to its trajectory and contributions to the field of nephrology by its faculty.  Second, it offers education and academic training that no other program matches, including research, clinical educator, and transplant tracks which I was drawn into. Third, it offers ample clinical training in several hospitals, which definitely provides exposure to different patient populations. Besides, Denver is one of the greatest cities to live in that offers a great quality of life compared to other cities in the US. 

Second-Year Fellows 

Shannon Lyons, DOLyons

Hometown: Rockford, Washington 

Medical School: Pacific Northwest University of Health Sciences 

Residency: Parkview Health System

Research/Clinical Interests: I love teaching especially when it comes to electrolytes, acid/base, and renal physiology. I also have a special interest in ESRD and renal replacement therapies and how we can improve the quality of life of ESRD patients.

Hobbies: Reading, hanging out with my dog Honey, trying (and usually failing) to grow my little house plants, and exploring the many breweries that Colorado has to offer!

Why did you choose the University of Colorado? The quality of the teaching and wide variety of clinical experience was what initially attracted me but what really won me over was the people. The faculty is incredible and really loves to teach and I could sense how collegial the atmosphere was amongst the fellows.


Marissa O'Keeffe, MD
martin, marissa

Hometown: St. Paul, MN

Medical School: University of Iowa

Residency: University of Colorado

Research/Clinical Interests: Use of Crit-Line/relative blood volume monitoring in hospitalized patients receiving dialysis, treatment of pregnant women with CKD (pre-pregnancy counseling in addition to management during pregnancy), and medical education.

Hobbies: Running, patio hopping, playing in the park with my puppy, spending as much time in the mountains as possible, hiking, camping, skiing, and paddle boarding with my fiancé

Why did you choose the University of Colorado? After interacting with the nephrology department during my time in residency here, I couldn't imagine going anywhere else. It is a fantastic group full of welcoming, driven, accomplished, brilliant people and I can't wait to learn from them for two more years. I'm excited for the diversity of patients and conditions between our three sites and the vast clinical, medical education, research, and mentorship opportunities available. 


Abdul-Rehman Syed, DOAbdul-Rehman Syed

Hometown: Dallas, TX


Medical School: Lake Erie College of Osteopathic Medicine


Residency: The University of Texas Medical Branch at Galveston


Research/Clinical Interests: Peritoneal/home dialysis, Glomerulonephritis, AKI's, medical education


Hobbies: I enjoy reading, trying new cuisines, exploring museums, and binge-watching TV


Why did you choose the University of Colorado? I chose the University of Colorado because it is a top-ranked nephrology program where I knew I would get excellent training. The faculty I met during the interview were friendly and very passionate about medical education. I knew this program would help me carve out the kind of career I wanted.  The program really emphasizes fellow wellness. And overall, Denver is just a great city to live in! 


Manny Urra, MDManny Urra

Hometown: Miami, FL


Medical School: Creighton University, Omaha NE


Residency: University of Colorado, Denver CO


Research/Clinical Interests: Medical Education, Critical Care Nephrology, Electrolyte Derangements


Hobbies: Weightlifting, cycling, and spending time exploring with my wife, Claire, and one year old baby, Esme


Why did you choose the University of Colorado?

I was very impressed with how happy and clinically excellent the first-year fellows were after rotating with them as a resident. The faculty is extremely approachable and motivated to help you succeed based on your career goals. The three-hospital system allows for exposure of diverse patient populations.


Chris Yang, MD
Yang, Chris

Hometown: Wichita, KS

Medical School: University of Cincinnati

Residency: Indiana University

Research/Clinical Interests: 

Home dialysis, healthcare disparities, hypertension, cardiorenal syndrome and diuretic resistance

Hobbies: Dining; (tiki) cocktails; computer, board, and card gaming; crossword puzzles; watching the NBA and MLB; reading science fiction; listening to bluegrass, (classic) country, hip hop, and EDM

Why did you choose the University of Colorado? My impression on the interview day was that this was the program that most genuinely cared about the education and wellness of its fellows. The world-renowned faculty, the beauty and excitement of Colorado and Denver, and the overall happiness of the fellows were all major draws as well.



Dual Adult-Peds Fellows


Angela Dixon, MDAngelina Dixon

Hometown: Pittsburgh, PA

Medical School: Pennsylvania State University College of Medicine

Residency: Tulane University Internal Medicine-Pediatrics

Research/Clinical Interests: Transitions of Care, Nephrology Medical Education, Quality of Life for ESRD Patients

Hobbies: Singing, writing/arranging music, working on my latest Pinterest fail, hiking, biking, skiing, and doing whatever it takes to tire out my Australian Shepherd, Oaklie

Why I chose Colorado: The program is very fellow-centric! I felt that I would get a great education and incredible mentorship and would be supported in my individual career goals, whatever those may be.

Shrey Purohit, MDPurohit, Shrey

Hometown:  Los Angeles, CA

Medical School: University of Michigan Medical School

Residency:  Duke University

Research/Clinical Interests:  Long term outcomes for CKD in younger populations, inherited kidney diseases, immunology

Hobbies:  reading, cooking, building computers

Why did you choose the University of Colorado? The University of Colorado provided me with the opportunity to create my own clinical pathway and explore my research interests. The faculty is extremely collegial and strongly invested in their fellows. Denver is also a great city to explore and has something for everyone!

Chief Nephrology Fellow


Amy Li, MD

Amy Li

Hometown: Honolulu, Hawaii


Medical School: University of Hawaii John A. Burns School of Medicine


Residency: University of Colorado


Research/Clinical Interests: I love electrolytes (especially hyponatremia), acid/base, AKI, CKD, and dialysis so... All of it! I'm also particularly interested in basic science research.


Hobbies: wildlife/bird photography, cooking, traveling, and kitty cats - I have three cats with more room to love (in my heart but not at home). Also, I am an avid not-skier, not-snowboarder, and I don't follow sports! 


Why did you choose the University of Colorado?

The faculty, no doubt! The faculty is full of supportive, kind-hearted people. I met the renal faculty as early as when I interviewed for residency, and they have supported me throughout the years without fail. They are so approachable and engaging and truly have the best interests of the learners at heart (medical students, residents, and fellows alike). Also, we're so lucky to rotate through three different hospitals - an academic hospital (UCH), our county and safety-net hospital (Denver Health), and the VA. What's not to love about CU?




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