Meet Our Providers 

Gina Valente Moore BSN,MSN, ND, RN, PNPc, FNP

Dr. Gina has been specializing in gastroenterology, in particular liver disease, for the last 10 years. She obtained her Bachelors of Science in Commerce Marketing in 1991 from Santa Clara University. From there, Dr. Gina studied at Case Western Reserve University in Cleveland Ohio where she obtained her Bachelors of Science in Nursing, Masters of Science in Nursing and her Doctor of Nursing Practice. She then went on to acquire her Post Masters Family Nurse Practioners in 2000 from Sonoma State University in Rohnert Park California.
Dr. Gina is providing comprehensive care to all types of patients here at Mathiesen Memorial Health Clinic.

David DeMattei  PA-c

David DeMattei is a Certified Physician Assistant who completed his medical training at Stanford University in Palo Alto, California. Born and raised in Tuolumne County, he worked extensively as an Emergency Medical Technician before pursuing his education at the Stanford School of Medicine. He enrolled at Stanford in hopes of one day bringing his knowledge back to his home town; he is pleased to have accomplished this by joining the team at Mathiesen Memorial Health Clinic. He and his wife live in Sonora; they enjoy hiking, camping, and snowboarding. David looks forward to serving the families of Tuolumne County and seeing patients of all ages.

Melissa Ronneburg  FNP

Melissa Ronneburg is a family nurse practitioner. She completed her degree at Loma Linda University in Southern California. After finishing school she worked in a very busy asthma and allergy practice. Melissa and her husband moved to Sonora 2003. It did not take long to consider Sonora home. In January 2015 Melissa joined the Mathiesen Memorial Health Clinic family. She is enjoying being back practicing medicine after taking a brief leave of absence while raising her children. In her “spare time”, Melissa is active in her children’s school, soccer and 4-H. The Ronneburg family enjoys camping and fishing in the Sierras.

Mathiesen Memorial Health Clinic & Chicken Ranch Rancheria  Mission Statement : A healthy body is the foundation towards life’s balance with mind and spirit. The Mathiesen Memorial Health Clinic will be partner for life with the greater Jamestown Indian and general community along this path.

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