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Our Physicians: Porter Ranch

Primary Care

Michelle Lin Emi, MD
Internal Medicine

Dr. Michelle Lin Emi studied bioengineering while earning her Bachelor of Science degree in Life Sciences at the Massachusetts Institute of Technology. She assisted with the development of biopharmaceuticals at Biogen Corporation in Cambridge, MA. She went on to earn her medical degree at the University of Pennsylvania School of Medicine and then completed internship and residency in Internal Medicine at UCLA Center For the Health Sciences. She is board certified in Internal Medicine, and is a member of the American College of Physicians. Dr. Emi began her internal medicine and primary care practice at HealthCare Partners Medical Group in Pasadena, CA, where she developed an interest in women's health care. After taking time away from practice to raise family, she now returns to UCLA School of Medicine, where she is currently a Clinical Instructor of Medicine. She regularly volunteers at Conejo Free Clinic and Westminster Free Clinic. Dr. Emi believes in a personalized, compassionate, comprehensive approach to care, tailored to each individual patient. She promotes being proactive, emphasizing a preventative approach, and looks forward to guiding each patient toward optimal health. More»

Alina Katsman, MD
Family Medicine

Dr. Alina Katsman was raised in Los Angeles. She studied microbiology, immunology, and molecular genetics and earned her Bachelor of Science degree from UCLA. She went on to earn her medical degree from the David Geffen School of Medicine at UCLA followed by an internship and residency in Family Medicine at UCLA. Dr. Katsman's interests include pediatrics, adolescent health, and women's health. More»

Judy Kim-Hwang, MD, Porter Ranch, Internal Medicine Judy Kim-Hwang, MD
Internal Medicine

Dr. Judy Kim-Hwang earned her medical degree at the University of California, San Francisco School of Medicine. She completed her internship and residency in internal medicine at UCLA School of Medicine. More»



Roland Sakiyama, MD, Porter Ranch, Internal Medicine Roland Sakiyama, MD
Internal Medicine

Dr. Roland Sakiyama earned his medical degree at UCLA School of Medicine. He completed his internship, residency and fellowship in medicine/endocrinology at the UCLA School of Medicine.  Dr. Sakiyama's clinical interest is general internal medicine. More»
Shirley Uy, MD, Porter Ranch, Family Medicine Shirley Uy, MD
Family Medicine

Dr. Shirley Uy earned her medical degree at UCLA School of Medicine. She completed her internship and residency in family practice at UCLA School of Medicine. Dr. Uy's clinical interest is women's health. More»

Specialty Care

Jeremy A. Cholfin, MD, Ph.D.

Dr. Jeremy Cholfin completed a bachelor's degree in Neuroscience and minored in Classics at UCLA. He earned his MD and PhD in Neuroscience at the University of California, San Francisco. After completing his medical internship at Santa Clara Valley Medical Center in San Jose, California, he moved back south and completed residency in Neurology at UCLA and fellowship in Clinical Neurophysiology at UCLA.


Dr. Cholfin is board certified in Neurology and has particular clinical interests in neurohospitalist care, stroke, epilepsy, neuro-immunology, and dementia. He has specialized training in EEG interpretation, EMG/nerve conduction studies, evoked potentials, epilepsy and intensive care unit EEG monitoring.


Dr. Cholfin's philosophy is one of collaboration with multiple team members to care for and treat the whole patient. He is highly committed to providing outstanding patient care, conducting research to advance the field of neurology, and teaching the next generation of physicians. More»

Melissa Cohen, MD, Porter Ranch, Hematology/Oncology Melissa J. Cohen, MD

Dr. Melissa J. Cohen is assistant clinical professor of medicine at the David Geffen School of Medicine at UCLA and a board certified medical oncologist practicing at UCLA Hematology/Oncology in Westlake Village and Porter Ranch. She began her medical training at George Washington University in Washington D.C., and then moved to Denver where she completed her internal medicine residency training at the University of Colorado.  In 2008, she relocated to Southern California to complete her fellowship training in both geriatrics and medical oncology at UCLA.  Her goal is to deliver individualized care of the highest quality, using state-of-the-art medical science, while focusing on all aspects of the patient's experience- physical, emotional, psychological as well as spiritual. More»
Ora Fried, MD
Pulmonary Disease

Dr. Ora Fried attended medical school at Sackler School of Medicine-New York Program in Tel Aviv, Israel. She then did a Medicine-Pediatrics residency in Phoenix, Arizona followed by a Pulmonary and Critical Care fellowship at California Pacific Medical Center and Alameda County Medical Center in San Francisco/Oakland, California.

Her interests include general pulmonology, asthma, chronic obstructive lung disease, tuberculosis, interstitial lung disease and pulmonary hypertension as well as healthcare disparities in minority populations and quality improvement. She spends her free time volunteering in a tuberculosis hospital in Haiti, hiking, and participating in triathlons and marathons. More»

John Glaspy, MD

John Glaspy, MD, MPH, is professor of medicine at the Jonsson Comprehensive Cancer Center (JCCC) of the University of California, Los Angeles (UCLA) School of Medicine. Dr. Glaspy holds the Estelle, Abe, and Marjorie Sanders Endowed Chair in Cancer Research. He is director of the JCCC Clinical Research Unit and director of the JCCC Women's Cancer Research Program.

Dr. Glaspy is a member of the American Society of Clinical Oncology, Southwest Oncology Group, American Federation for Clinical Research, International Society of Interferon Research, and American Society of Nuclear Medicine, among others. He is also a fellow of the American College of Physicians. During the course of his career, Dr. Glaspy has authored more than 270 articles, abstracts, and book chapters. He has received numerous awards and honors, including being named one of the "Best Doctors in America."

Currently, Dr. Glaspy is involved in basic research in tumor immunology and the effects of fatty acids on carcinogenesis. His clinical interests also include chemotherapy-induced anemia, the role of hematopoietic growth factors in cancer management, and new approaches to the treatment of breast cancer and malignant melanoma. Dr. Glaspy received his MD from the UCLA School of Medicine and his MPH in health services administration from the UCLA School of Public Health. He completed his residency in internal medicine and his fellowship in hematology and oncology at the UCLA School of Medicine. More» 

Puja Goswami, MD

Dr. Puja Goswami earned her medical degree at Northeastern Ohio Universities College of Medicine. She attended University Hospital at Case Western Medical Center for internal medicine residency and subsequently completed her nephrology fellowship training at the University of Michigan.

Dr. Goswami's research projects in the past consisted of developing a risk prediction score for progression of stage 4 chronic kidney disease to end stage renal disease in the VA population, and determining the important predictors for mortality in timing of dialysis in acute kidney injury for the patients admitted at University of Michigan intensive care units over 2011-2012. Her research interests include hypertension and acute kidney injury. During her spare time, Dr. Goswami enjoys hiking, traveling, and cooking. More »

Maggie Ham, MD
Digestive Diseases

Dr. Ham earned her medical degree at the David Geffen School of Medicine at UCLA and then completed her residency in internal medicine at UCLA.  She then moved east for gastroenterology fellowship training at Beth Israel Deaconess Medical Center, a teaching hospital of Harvard Medical School. Her research interests have included peptic ulcer disease, mucosal defense and inflammatory bowel disease.  She has had several peer reviewed publications and is board certified in internal medicine and gastroenterology.

She practices general gastroenterology with interests in women's health, inflammatory bowel disease, peptic ulcer disease, celiac disease, irritable bowel syndrome, gastroesophageal reflux disease, colorectal cancer screening, fecal incontinence, liver disease. More»


James S. Lee, MD, Porter Ranch, Cardiology James S. Lee, MD
Interventional Cardiology

Dr. James Lee is originally from New York where he attended Cornell University and earned a bachelor's of science in applied economics, business management, and marketing. He then earned a medical degree from Loma Linda University followed by an internship and residency in Internal Medicine at the Cleveland Clinic Foundation. Dr. Lee then pursued a fellowship in Cardiovascular Medicine at the UCLA San Fernando Valley Program where he served as the chief Cardiology fellow for the VA Greater LA Healthcare System and Olive View Medical Center. Dr. Lee also completed an Interventional Cardiology Fellowship at the Mount Sinai Hospital in New York.

Dr. Lee specializes in the management of coronary artery disease with complex coronary interventions utilizing intravascular ultrasound, fractional flow reserve, and rotational atherectomy. Dr. Lee also has a special interest in vascular closure devices and transradial interventions and has helped develop hospital policies and programs to facilitate ambulatory percutaneous coronary interventions in the community. Dr. Lee is committed to excellence in comprehensive health care and in understanding patient's health care needs in conjunction with implementation of state-of-the-art techniques and compassionate care. More»
Kellie Lim, MD

Dr. Kellie Lim is a true Bruin, having completed all of her medical training at the David Geffen School of Medicine at UCLA. After earning her medical degree, Dr. Lim completed internship and residency in pediatrics before pursuing fellowship training in allergy & immunology and pharmacology. Dr. Lim is board certified in both pediatrics and allergy & immunology. More»
Lisa Little, MD

Dr. Lisa Little is a native of Southern California, practicing in the San Fernando Valley since 2007. Dr. Little earned her medical degree at Ross University School of Medicine in New York and completed her internship at Geisinger Health System in Pennsylvania. She completed her residency in Ob/Gyn at Southern Illinois School of Medicine in Springfield where she served as Chief Resident and received numerous honors for her ovarian cancer research. More»

Rebecca Liu, MD, Porter Ranch, Pulmonology Rebecca Liu, MD
Pulmonary Disease

Dr. Rebecca Liu was born in Denver and raised in New Jersey. The oldest of three children to Chinese immigrants, she attended the University of Texas at Austin earning a B.A. in biology. Before becoming a physician, Dr. Liu earned a Master of Science degree in Nursing from the University of Texas at Austin and practiced as a RN for several years.  She then attended medical school at Texas Tech University Health Sciences Center, completing her internal medicine residency at the University of Texas at Southwestern Medical Center and Parkland Hospital in Dallas, TX.  Moving west, Dr. Liu completed a pulmonary/critical care fellowship at Harbor-UCLA. In her free time, Dr. Liu enjoys reading, cycling, swimming and traveling with her family. More »
Carlos Macias, MD

Dr. Carlos Macias brings the specialized medicine of the UCLA Cardiac Arrhythmia Center to Porter Ranch. He earned his medical degree in Mexico and completed internship and residency training in internal medicine at the University of New Mexico Medical Center. Dr. Macias completed a fellowship in cardiovascular disease at the University of New Mexico Medical Center and then moved to the Davide Geffen School of Medicine at UCLA for an additional fellowship in clinical cardiac electrophysiology. His clinic interests include ablation, arrhythmia, atrial fibrillation, electrophysiology, implantable defibrallators and pacemakers. More»

Jelena Maletkovic, MD

Dr. Jelena Maletkovic earned her medical degree at the University of Belgrade Faculty of Medicine. She completed her internship and residency in internal medicine at Interfaith Medical Center in Brooklyn, New York. Dr. Maletkovic completed fellowship training in endocrinology, diabetes and metabolism at the David Geffen School of Medicine at UCLA. Dr. Maletkovic's clinic interests include adrenal disorders, diabetes, general endocrinology, hypogonadism, metabolic syndrom, obesity, pituitary and thyroid disorders. More»
Maryum Merchant, MD, Porter Ranch, Pulmonary Disease
Maryum Merchant, MD
Pulmonary Disease

"As a pulmonologist, my mission is to help patients in our community breathe better and be able to enjoy a good quality of life. I joined UCLA Health because I can provide my patients the highest level of care by blending the academic research knowledge of UCLA with evidence-based medicine."

Dr Merchant worked as a private practice hospitalist in Southern California for three years after completing her residency in Internal Medicine at UCSF-Fresno in 2007. She then pursued a fellowship in Pulmonary/Critical Care Medicine at Cedars-Sinai Medical Center. Over the course of her fellowship, she has gained significant experience in managing patients with advanced lung disease, including transplant, chronic obstructive lung disease, pulmonary hypertension, and interstitial lung disease. She is currently a Clinical Instructor of Medicine at David Geffen-UCLA School of Medicine. She is also a member of American College of Chest Physician (ACCP) and American Thoracic Society (ATS). More»

Geraldine Navarro, MD, Porter Ranch, Rheumatology Geraldine Navarro, MD

Dr. Geraldine Navarro earned her medical degree from UCLA School of Medicine. She completed her internship and residency in internal medicine at Olive View-UCLA Medical Center. She completed her fellowship in rheumatology at UCLA School of Medicine. More»
Vikas Pabby, MD
Digestive Diseases

Vikas Pabby, MD, MPH, grew up in Southern California after which he went to Bangalore, India to attend medical school at MS Ramaiah Medical College. He subsequently completed his residency in internal medicine and pediatrics at University of Southern California, LA County. He then worked as an associate physician in internal medicine at Brigham and Women's Hospital in Boston, MA and was appointed instructor of medicine at Harvard Medical School, practicing full time internal medicine and part time pediatrics. Dr. Pabby then went on to pursue fellowship training in gastroenterology and hepatology at the Brigham and Women's Hospital / Harvard Medical School Program. During the third year of fellowship, he was recognized for teaching and was awarded a fellowship-teaching award by the department of medicine. During his fellowship, Dr. Pabby obtained a master's degree in public health from the Harvard School of Public Health, Boston, MA.

Dr. Pabby is board-certified in gastroenterology, internal medicine and pediatrics. He is a member of the American College of Gastroenterology, American Gastroenterology Association, the Crohn's and Colitis Foundation of America and the American Society of Gastrointestinal Endoscopy. Dr. Pabby practices genera lgastroenterology with an interest in inflammatory bowel disease. More»

Martin Palmer, MD

Martin C. Palmer, MD, FRCPC, FRACP is Clinical Professor of Medicine at the David Geffen School of Medicine at UCLA.  Dr. Palmer practices at UCLA Hematology/Oncology based in Westlake Village and Simi Valley, specializing in medical oncology.

Dr. Palmer received his medical degree with distinction (summa cum laude) at the University of Otago in New Zealand. He completed his internal medicine residency in New Zealand and his fellowship training in medical oncology at the Cross Cancer Institute and University of Alberta.  He is board certified in internal medicine and medical oncology with the Royal Australasian College of Physicians and the Royal College of Physicians of Canada. At the University of Alberta, he went on to serve as Professor of Medicine, the Assistant Dean of Clinical Education and Director of the Medical Oncology Fellowship training program in medical oncology. He is the recipient of numerous teaching and academic awards. He has also worked in biotechnology clinical trials research and a community oncology practice in California before joining UCLA Health in 2012. More»
Veena Vanchinathan, MD, Porter Ranch, Dermatology Veena Vanchinathan, MD

Dr. Vanchinathan earned her medical degree at UCLA David Geffen School of Medicine. Heading north, she completed her internship at Santa Clara Valley Medical Center in the Bay Area and then moved east to complete her residency in dermatology at Henry Ford Hospital in Detroit. Dr. Vanchinathan has now returned home to Southern California to practice at UCLA Health in Porter Ranch. More »


Porter Ranch Hematology Oncology physicians are located in the same building in Suite 310 »