1661 Golden Rain Rd
Seal Beach, CA 90740
Phone: (562) 493-9581
Office Hours:
Monday - Friday: 8:00 am - 5:00 pm

Our Providers

The five full-time care providers of the Health Care Center were each hand-picked for their experience and skill treating older adults. Our staff also works closely with a team of other specialists who may hold office hours at the Health Care Center.

Our Physicians:

Puja Shrestha, M.D.
Board Certified Internal Medicine Doctor

Dr. Shrestha comes from a family of physicians, including her father, as well as many of her aunts and uncles. Seeing the passion, dedication, and satisfaction her relatives received from caring for patients greatly influenced Dr. Shrestha to pursue a career in medicine. However, it was a unique relationship with her grandmother and the experience of caring for her which ultimately inspired Dr. Shrestha’s love of caring for seniors. Before coming to The Health Care Center, Dr. Shrestha worked as a primary care physician in Maine caring for senior patients by addressing their chronic and complex conditions through comprehensive, personalized care, focusing on preventative medicine and patient education.

Dr. Shrestha brings her warm personality, kindness, and compassion to The Health Care Center. She is committed to providing her patients with the tools necessary to live full and healthy lives, and encourages open communication during every patient visit. "I like to take my time getting to know each of my patients. I always encourage them to ask me questions because I never want them to leave their appointment confused and unsure. It is my hope that at the end of each visit my patients can leave confident of the care they are receiving, and clearly understand what next steps they need to take to improve or maintain their current health status."

Dr. Puja Shrestha earned her medical degree from Kathmandu University in Nepal. She completed her internship and residency at New York University, Woodhill Medical Center in Brooklyn, New York. In her spare time, Dr. Shrestha enjoys an active lifestyle, cooking, and spending time with her husband, who is also a physician, and their child.

Stela Kostova-Abadjieva, M.D.
Board Certified in Internal Medicine

Dr. Stela Kostova-Abadjieva is a board certified internal medicine doctor, and has been practicing medicine for almost 20 years. She earned her medical degree from the Medical University of Sofia, Bulgaria, and completed her residency in Internal Medicine at Kingsbrook Jewish Medical Center in Brooklyn, New York.

Her many years of experience as a physician in Bulgaria has taught her to see through the eyes of her patients, and has inspired the compassionate care she now brings as a primary care doctor at The Health Care Center. She believes that when there is greater communication between the patient and the doctor, more of the patient’s needs can be met, and patients are more likely to remain on a path toward a healthier future.

Sullyvan Tang, M.D.
Internal Medicine

Dr. Sullyvan Tang has been practicing internal medicine for more than 15 years. He was raised in Sacramento, California, and completed his undergraduate degree in engineering at the University of Southern California. While solving problems in that profession, he discovered a strong interest in healthcare and changed his career.

After successfully earning a medical degree from the State University of New York Health Science Center in Brooklyn and completing his residency at the University of California, Irvine, Medical Center in Orange, he entered the profession of internal medicine where he developed significant experience as a hospitalist, urgent care physician, and medical director with various organizations in California while securing an MBA degree in Health Care from The George Washington University Graduate School of Business.

In the most recent years, he has leveraged his medical and administrative skills to focus on direct patient care as a primary care physician. Dr. Tang values clear communication in the physician-patient relationship resulting in customized treatment plans with more successful outcomes.

Paul S. Yoon, M.D.
Family Practice

Dr. Paul Yoon was born and raised in Seoul, South Korea. He speaks fluent English and Korean and has been practicing medicine for more than 38 years. At the age of fifteen, Dr. Yoon and his family moved to Toronto, Canada where he attended high school and later earned his medical degree from the University of Toronto, School of Medicine. He completed his internship in Internal Medicine at the University of California, Irvine and Long Beach V.A. Hospital, and a family practice residency at the Riverside General Hospital.

As a young doctor, Dr. Yoon established his own solo practice that he ran for 28 years. He now joins the Health Care Center and brings with him his love for people and a commitment to helping senior patients enjoy the best quality of life as possible.

Interacting with his patients brings Dr. Yoon the most joy. He says, “People are enormously interesting. They are unique in every way, and it challenges me to work harder to provide the best care for each patient based on their individual needs.”

Dr. Yoon is passionate about helping his patients live out a full and happy life, especially throughout their older years. It is his belief that as we get older, social health, mental health, and having adequate support systems become increasingly important beyond one’s physical health status. He says that, “People living in their golden age do not always enjoy a golden life. I want to be able to help my older patients achieve a golden life in the best way I know how. It is my wish that all my patients have the opportunity to live fully all through their years.”

Sanat Patel, M.D.
Internal Medicine

Dr. Sanat Patel brings nearly 25 years of experience as a general internist to The Health Care Center. He is dedicated to serving his patients with high-quality, compassionate care. Dr. Patel brings his attentiveness and dedication to all of his patients. He makes the constant effort to connect with his patients, establish trusting relationships, and deliver personalized care. Dr. Patel has held a number of leadership positions with medical groups and hospitals including directorships and committee chairman roles. Dr. Patel attended medical school in India and completed his medical training in the United States at Lutheran Medical Center in Cleveland, Ohio. Before deciding to focus on internal medicine, he trained in surgery for two years.

Mary B. Sherman, M.D.
Board Certified in Internal Medicine and Nephrology
Qualification in Geriatric Medicine

Dr. Sherman completed her undergraduate degree at the University of San Francisco and her medical degree from Loyola Stritch School of Medicine, in Maywood, Illinois. She received her postgraduate training at Long Beach VA Hospital and UC Irvine. Dr. Sherman is a diplomat of the American Board of Internal Medicine and the subspecialty board of Nephrology (kidney disease). In 1994, she received an added qualification in Geriatric Medicine. Dr. Sherman has been practicing at the Health Care Center since November 1995.

Marie Puffpaff, GNP, RN

Marie Puffpaff has been serving members of the Leisure World community since 1990. Ms. Puffpaff received her undergraduate degree in nursing from the California State University at Long Beach. She received her Master of Nursing and Geriatric Nurse Practitioner from University of California, Los Angeles.

As a Nurse Practitioner, Ms. Puffpaff’s additional training allows her to perform physical exams and manage stable and chronic diseases such as diabetes and high blood pressure, including providing and adjusting medications. Patients are scheduled to see Ms. Puffpaff, in collaboration with their primary care physician.


If you and your primary care physician at the Health Care Center decide that you need specialized treatment, we will be happy to refer you to someone who can treat your individual needs. The Health Care Center arranges to have specialist visitors hold weekly office hours, and we will be happy to refer you to another physician offsite if you have specific needs.

Our specialists treat:

• Cardiology
• Chiropractor
• Gastroenterology
• Hematology/Oncology
• Ophthalmology
• Optometry
• Nephrology
• Pain Management
• Podiatry
• Psychiatry
• Surgery