Our Providers
John Larsen, MD
John Larsen has been a doctor at Uptown Pediatrics since 1985. A New Yorker since birth, Dr. Larsen received his BA at Queens College and his MD at Downstate Medical Center. He stayed in New York to complete his pediatric residency, chief residency, and pediatric infectious disease fellowship at Mount Sinai Hospital. Dr Larsen is a member of the American Academy of Pediatrics and a former president of the New York Pediatric Society. As an associate clinical professor and associate attending at Mount Sinai Hospital, he is actively involved in teaching medical students and residents. He has published several scholarly articles on topics in infectious disease, and remains the office expert on pediatric infectious disease and dermatology. Dr Larsen’s interests include, biking, reading, and music. He occasionally leaves the island of Manhattan to go hiking and enjoy the outdoors.
Beth Cohen, MD
Beth Cohen has been at Uptown Pediatrics since 1989. Dr. Cohen completed her undergraduate studies at University of Florida and Tulane, and her medical degree at University of Miami. She then moved to New York City where she completed three years of pediatric training at Mount Sinai Hospital. After completing residency, she went into private practice right away because she “absolutely loves children.” Dr. Cohen is an active member of the American Academy of Pediatrics and the New York Pediatric Society. She is married to a pediatrician, and is the proud mother of three children. Dr. Cohen loves biking, hiking, and traveling, and she is trying to learn to cook. She especially likes watching her patients grow up.
Ivanya Landon Alpert, MD
Ivanya Landon Alpert joined Uptown Pediatrics in 2006. Dr. Alpert is a native New Yorker (Ethical Culture ’83, NBS ’89) who received her BA from Harvard College in 1994 and her medical degree from The University of Pittsburgh in 2000. She then returned to New York to complete her pediatric residency and adolescent medicine fellowship at Mount Sinai Hospital. Dr. Alpert has particular expertise working with teenagers. She has presented nationally on various adolescent health topics, and is recognized as one of NY’s top doctors by both New York Magazine and Castle Connolly. She is currently a Clinical Assistant Professor at the Mount Sinai School of Medicine. When not in the office, Dr. Alpert enjoys spending time with her husband, a pediatric emergency physician, and their three children.
Jennifer Cerasoli, MD
Dr. Cerasoli joined the practice in 2009. After completing her undergraduate degree in Biology and Society at Cornell University, she went on to obtain her medical degree at New York Medical College and completed her pediatric residency at Mount Sinai Hospital where she served as Pediatric Chief Resident. Dr. Cerasoli is actively involved in teaching medical students and residents, and coordinates Uptown Pediatrics’ satellite clinic for pediatric trainees. Dr. Cerasoli is particularly interested in child advocacy and outreach to children with developmental disabilities. She is a Spanish-speaker and the mom of 3 wonderful children.
Michelle L. Klein, MD
Specialty: Pediatrics, Pediatric Endocrinology
Michelle Klein began working at Uptown Pediatrics in 2008. A California native, Dr. Klein received her BA in Neuroscience from UCLA, her master’s degree in Physiology and Biophysics from Georgetown University, and her medical degree from New York Medical College. Dr. Klein completed her pediatric residency, chief residency, and pediatric endocrinology fellowship at Mount Sinai Hospital. Dr. Klein loves sharing her knowledge with future pediatricians, and she was honored with the Arnold Gold Humanism in Medicine Teaching Award. Dr. Klein is particularly interested in growth and short stature, thyroid disease, children born small for gestational age, abnormal pubertal development, and she has authored many publications on these topics. In her spare time, Dr. Klein, who also has three children, enjoys traveling, playing volleyball, dancing, and spending quality time with family and friends.
Zoya Treyster, MD
Specialty: Pediatrics, Allergy and Immunology
Zoya Treyster, who is board-certified in both Pediatrics and Allergy/Immunology, joined Uptown Pediatrics in 2023. Dr. Treyster completed her undergraduate and medical school training at George Washington University, her pediatric residency at New York-Presbyterian Columbia, and her fellowship in Allergy/Immunology at Hofstra Northwell. Prior to joining Uptown Pediatrics, Dr. Treyster was a faculty member at Children’s Hospital at Montefiore where she served as Associate Medical Director of the Pediatric Asthma Center for three years. Dr. Treyster has expertise in treating asthma, environmental allergies, food and drug allergies, eczema, immunodeficiency, and autoinflammatory disorders. She has conducted original research and is a member of numerous professional organizations, including the AAAAI, the ACAAI, and the AAP. She currently serves on the executive committee of New York Allergy & Asthma Society. When not in the office, Dr. Treyster enjoys reading, hiking, and spending time with her husband, two young children, and two dogs.
Emese Szirtes, RN, IBCLC
Emese Szirtes also known as Nurse Mesi (mè-shee) has a vital role in helping to keep our patients healthy since 2006. In addition to her being the Practice’s Nursing Supervisor, Nurse Mesi holds certification in lactation counseling and is our in-house breast-feeding expert. When she’s not educating our parents on the safety and importance of vaccination and helping our new moms with breastfeeding, she’s spending quality time with her energetic son!