Beste Urologen in Istanbul - TOP -79 Ärzte

Assoc. Prof. Dr. Cenk Acar completed his medical education at Ankara University Faculty of Medicine and his urology residency at Gazi University Faculty of Medicine, Department of Urology. He worked as an assistant professor at Pamukkale University Faculty of Medicine, Department of Urology between June 2009 and November 2012. Between May 2012 and November 2012, he worked as a fellow in robotic and laparoscopic surgery in urologic cancers for 6 months in the Urology Department of “The Netherland Cancer Institute-AVL hospital”. He started to work at Acıbadem Ankara Hospital in November 2012. In September 2014, he completed the necessary academic qualifications and received the title of “Associate Professor”. After working in a private hospital in Ankara between 2015-2020, he continued his services in his private practice in Ankara until 2020 when he started Hisar Intercontinental Hospital.

In 2015, he was the chairman of the organizing committee of the first course on ‘Fluorescence Imaging in Urological Surgery’ in the field of urology in Turkey. In the following years, he chaired many urology and multidisciplinary courses on ICG fluorescence imaging under the umbrella of Urology Associations. In 2017, for the first time in Turkey, he started to apply Bipolar Prostate Enucleation in benign prostate enlargement in his clinic. Later, he started to use his increasing experience in surgeries such as HOLEP and THUFLEP.

In his career, Dr. Acar, who is especially interested in Urological Cancers, Urinary System Stones, HOLEP, THUFLEP, Endourology, and Robotic and Laparoscopic Urological Surgeries, has carried out many successful operations. He has performed over 500 urological cancer surgeries, over 250 HOLEP surgeries, countless endoscopic stone surgeries, and numerous robotic and laparoscopic surgeries.

FIELDS OF MEDICAL INTEREST

• Localized Prostate Cancer Treatments
• Quality of Life in Urological Cancers
• Sentinel Lymph Node Dissections in Prostate Cancer
• Intraoperative Fluorescence Imaging Techniques in Robotic and Laparoscopic Urological Surgery
• Prostate Enucleations in BPH (HOLEP, BIPOLEP, THULEP)
• Urinary System Stone Disease

d                                                                                                                                  d                                                                                                                                        d

Accepting patients in the Urology medical unit of Florya Hospital, Prof. Dr. Semih Ayan completed his education at Sivas Cumhuriyet University Faculty of Medicine in 1997 and received the title of Urology Specialist. In 1999, he became a Postdoctoral Fellow in Pediatric Urology at Harvard University; He became Associate Professor of Urology in 2003 and Professor of Urology in 2009. In 2015, he completed his Minimal Invasive Urological Oncology (Clinical Fellow) studies at the University of Chicago and crowned his professional education and experience with international studies.

In the field of Urological Oncology, which is one of the physician's areas of interest, surgical treatment of prostate cancer, bladder cancer and kidney tumors provides a significant increase in the survival rate and the chance of surviving cancer. In the field of Pediatric Urology, which is another area of interest, congenital anomalies such as renal outflow stenosis, urinary reflux to the kidney and hypospadias are corrected by using innovative surgical applications and a lifelong contribution is provided to the patients.

Medical equipment required for medical diagnosis, treatment and surgical treatment to be given in the areas specified in our urology units, laparoscopic surgeries and all kinds of equipment suitable for the use of new surgical techniques are available in our hospital. With the treatment and operations performed in our hospitals by making use of the best facilities offered by medical technology, a significant increase in the quality of life is achieved while the patients are healed.

prof. Dr. Semih Ayan received almost all of his medical education and certificates from the leading institutions of America and Europe, and gained deep knowledge and international experience in many advanced specialties of urology. prof. Dr. Among the trainings and certificates Ayan has received internationally;

American Medical License (USML)

Pediatric Urology Fellow (1999-2000/Boston, USA)

Urological Oncology Fellow (2014-2015/USA).

Assist. Op.Dr.Oğuzhan Parlakkılıç graduated from Atatürk University Faculty of Medicine in 2001.

He started his specialization in the urology clinic of Taksim Training and Research Hospital in 2002. Having completed his specialization training in 2007, Dr. Oğuzhan Parlakkılıç attended many national and international meetings. He has studies in andrology, endourology and urooncology.

Between 2007 and 2009, he completed his duty of public service obligation at Sivelek State Hospital.

Between 2009 and 2010, he worked as a urology specialist in the General Command of Mapping Dispensary. 

Marital Status : He is married, his wife is an ophthalmologist, and he is the father of two sons, aged 27 (Medical doctor) and 20 (Student).

Educational Status

1988 Uludağ University Faculty of Medicine / Bursa

1982 Kabataş Boys' High School / Istanbul

1979 Göztepe Secondary School / Istanbul

1976 Harun Reşit Primary School / Istanbul

Institutions he works for

2020 Biruni University Hospital, Head of Urology Department / ISTANBUL
2017 Yeni Yüzyıl University Gaziosmanpaşa Hospital, Head of Urology Department / ISTANBUL

2016 Taksim Training and Research Hospital Urology Clinic Education and Administrative Supervisor / Istanbul

2009 Bağcılar Training and Research Hospital Urology Clinic Chief / Istanbul

2007 International Hospital, Yeşilköy / Istanbul

2007 Ankara Training and Research Hospital 2nd Urology Clinic / Ankara

2001 Military Service, Marshal Fevzi Çakmak Military Hospital / Erzurum

1999 Bergama State Hospital / Izmir

1997 Ankara Training and Research Hospital Specialization Program / Ankara

1992 Izmit State Hospital / Izmit

 

diplomas

2011 Professorship

2006 Associate Professorship

1997 Urology Specialist

1988 Doctor of Medicine

Associations and organizations of which he is a member

European Association of Urology

Turkish Urology Association

Northern Marmara Urology Association

Endourology Association

Nuhoğlu Foundation

Scientific Publications

Author of over 100 publications, presentations and book chapters, 58 of which are international.

Urology

Fields of Study and Interests

• Urooncology

• Prostate cancer

• Bladder Cancer

• laparoscopy

• Endourology

• Robotic Surgery

• Stone Diseases

• Andrology

• İnfertility

Education

• Health Sciences University GOP Taksim Training and Research Hospital Urology Specialization

Training 2017, Istanbul / Turkey

• Istanbul University Faculty of Medicine Medical Doctor Education 2011, Istanbul / Turkey

Career

• Yeni Yüzyıl University Private Gaziosmanpaşa Hospital 2020-2021, Istanbul / Turkey

• Sisli Florence Nightingale Hospital 2020, Istanbul / Turkey

• GOP Taksim Training and Research Hospital 2017-2020, Istanbul / Turkey

• GOP Taksim Training and Research Hospital (Medical Specialization Training) 2012-2017,

Istanbul / Turkey

• Marmara Ereglisi District State Hospital 2011, Istanbul / Turkey

Publications: Cilesiz NC, Erdoğan N, Özkan A, Kalkanlı A, Hazar Aİ, Balcı MBC, Aydın M, Özdemir

E. Pleomorphic undifferentiated sarcoma: A case of a giant renal mass. Urol Case Rep. 2018 Jan

8;17:44-47. doi: 10.1016/j.eucr.2018.01.002. eCollection 2018 Mar. PubMed PMID:

EXPERIENCE*

2019 - Present, Istanbul/Istanbul/Turkey

MEMORIAL ATAŞEHİR HOSPITAL

General Surgeon

2012 - 2019, Diyarbakır/Diyarbakır/Turkey

DİCLE UNIVERSITY FACULTY OF MEDICINE

General Surgeon

2011 - 2012, Van/Van/Turkey

VAN REGIONAL TRAINING AND RESEARCH HOSPITAL

General Surgeon

2009 - 2011, Van/Van/Turkey

HAKKARİ STATE HOSPITAL

General Surgeon

2004 - 2009, Van/Van/Turkey

YÜZÜNCÜYIL UNIVERSITY FACULTY OF MEDICINE

General Surgeon

2002 - 2004, Van/Van/Turkey

HACIBEKİR HEALTH CENTER

General Practitioner

*EDUCATION*

2018 - 2019, Diyarbakır/Turkey

Associate Professor

2015, Ohio/USA

OHIO STATE UNIVERSITY WEXNER MEDICAL CENTER

Neck Dissection Training

2012 - 2018, Diyarbakır/Turkey

Assistant Professor

1996 - 2002, Adana/Turkey

ÇUKUROVA UNIVERSITY

FACULTY OF MEDICINE - Medical Doctor Education

Experience

2017 - 2022 Haseki Training and Research Hospital, Associate Professor

2017 - 2022 Haseki Training and Research Hospital

2013 - 2017 Haseki Training and Research Hospital

2013 - 2017 Haseki Training and Research Hospital, Chief Resident

2010 - 2013 Silivri State Hospital (Compulsory Service Obligation)

2008 - 2008 University of Michigan Medical School

2005 - 2010 Istanbul Medical Faculty, Department of Urology

Education

2010 Istanbul University, Istanbul Medical Faculty, Department of Urology

2004 Istanbul University, Istanbul Medical Faculty

Publications

International Peer-Reviewed Journals:

Culpan M, Atis G, Sanli O, Bozkurt Y, Atmaca AF, Semerci B, Kutsal C, Canda AE, Akbulut F, Tugcu V, Boylu U, Erturhan S, Koca O, Ateş F, Halis F, Soyupek S, Turna B, Cakmak S, Sahin S, Erdem S, Yildirim A. "Comparison of Tumor Enucleation and Standard Partial Nephrectomy According to Trifecta Outcomes: A Multicenter Study by the Turkish Academy of Urology, Uro-Oncology Working Group." J Invest Surg. 2022 May;35(5):1112-1118.

Sahan M, Sarilar O, Akbulut MF, Demir E, Savun M, Sen O, Ozgor F. "Flexible ureterorenoscopy and laser lithotripsy with regional anesthesia vs general anesthesia: A prospective randomized study." Int Braz J Urol. 2020 Nov-Dec;46(6):1010-1018.

Cubuk A, Yanaral F, Savun M, Ayranci A, Erbin A, Yazici O, Akbulut MF, Sarilar O. "Modified autologous transobturator tape surgery - evaluation of short-term results." Ginekol Pol. 2020;91(2):51-56.

Kandemir E, Savun M, Sezer A, Erbin A, Akbulut MF, Sarilar Ö. "Comparison of Miniaturized Percutaneous Nephrolithotomy and Standard Percutaneous Nephrolithotomy in Secondary Patients: A Randomized Prospective Study." J Endourol. 2020 Jan;34(1):26-32.

Ucpinar B, Erbin A, Ayranci A, Caglar U, Alis D, Basal S, Sarilar O, Akbulut MF. "Prediction of recurrence in non-muscle invasive bladder cancer patients. Do patient characteristics matter?" J BUON. 2019 Jul-Aug;24(4):1659-1665.

Ozdemir H, Erbin A, Sahan M, Savun M, Cubuk A, Yazici O, Akbulut MF, Sarilar O. "Comparison of supine and prone miniaturized percutaneous nephrolithotomy in the treatment of lower pole, middle pole and renal pelvic stones: A matched pair analysis." Int Braz J Urol. 2019 Sep-Oct;45(5):956-964.

Erbin A, Ucpinar B, Cubuk A, Yazici O, Uysal H, Savun M, Basal S, Akbulut MF. "The Impact of Sheath Size in Miniaturized Percutaneous Nephrolithotomy in Adult Patients; A Matched-pair Analysis." Urol J. 2019 Dec 24;16(6):536-540.

Güler A, Erbin A, Ucpinar B, Savun M, Sarilar O, Akbulut MF. "Comparison of miniaturized percutaneous nephrolithotomy and standard percutaneous nephrolithotomy for the treatment of large kidney stones: a randomized prospective study." Urolithiasis. 2019 Jun;47(3):289-295.

Yanaral F, Ozgor F, Savun M, Agbas A, Akbulut F, Sarilar O. "Shock-wave Lithotripsy for Pediatric Patients: Which Nomogram Can Better Predict Postoperative Outcomes?" Urology. 2018 Jul;117:126-130.

Arslan B, Akbulut MF, Onuk O, Küçüktopçu O, Çilesiz NC, Ozkan A, Yazıcı G. "A comparison of Amplatz dilators and metal dilators for tract dilatation in mini-percutaneous nephrolithotomy." Int Urol Nephrol. 2017 Apr;49(4):581-585.

Akbulut F, Kucuktopcu O, Kandemir E, Ucpinar B, Ozgor F, Simsek A, Arslan B, Erbin A, Yanaral F, Binbay M, Gurbuz G. "Efficacy and safety of mini percutaneous nephrolithotomy in obese patients." Springerplus. 2016 Jul 22;5(1):1148.

Sancak EB, Oguz S, Akbulut T, Uludag A, Akbas A, Kurt O, Akbulut MF. "Female sexual dysfunction in androgenetic alopecia: Case-control study." Can Urol Assoc J. 2016, July;10(7-8):E251-256.

Akbulut F, Kucuktopcu O, Kandemir E, Sonmezay E, Simsek A, Ozgor F, Binbay M, Muslumanoglu AY, Gurbuz G. "Comparison of flexible ureterorenoscopy and mini-percutaneous nephrolithotomy in treatment of lower calyceal stones smaller than 2 cm." Ren Fail. 2016;38(1):163-7.

Tok A, Akbulut F, Buldu I, Karatag T, Kucuktopcu O, Gurbuz G, Istanbulluoglu O, Armagan A, Tepeler A, Tasci AI. "Comparison of microperc and mini-percutaneous nephrolithotomy for medium-sized lower calyx stones." Urolithiasis. 2016 Apr;44(2):155-9.

Akbulut F, Tok A, Penbegul N, Daggulli M, Eryildirim B, Adanur S, Gurbuz G, Celik H, Utangac MM, Dede O, Bodakcı MN, Tepeler A, Sarica K. "Colon perforation related to percutaneous nephrolithotomy: from diagnosis to treatment." Urolithiasis. 2015 Nov;43(6):521-6.

Ozluk Y, Sari S, Guzel NT, Firat P, Akbulut F, Kilicaslan I. "Mixed epithelial and stromal tumor of the kidney with sarcomatous transformation metastatic to the lung: A case report." Anal Quant Cytopathol Histpathol. 2015 Jun;37(3):199-205.

Ozgor F, Kucuktopcu O, Sarilar O, Toptas M, Simsek A, Gurbuz ZG, Akbulut MF, Binbay M. "Does previous open renal surgery or percutaneous nephrolithotomy affect the outcomes and complications of percutaneous nephrolithotomy." Urolithiasis. 2015 Nov;43(6):541-7.

Ugurlu İM, Akman T, Binbay M, Tekinarslan E, Yazıcı Ö, Akbulut MF, Özgör F, Müslümanoğlu AY. "Outcomes of retrograde flexible ureteroscopy and laser lithotripsy for stone disease in patients with anomalous kidneys." Urolithiasis. 2015 Feb;43(1):77-82.

Simsek A, Ozgor F, Kirecci SL, Akbulut MF, Sonmezay E, Yuksel B, Kucuktopcu O, Gurbuz ZG. "Results of tension-free vaginal tape for recurrent stress urinary incontinence after unsuccessful transobturator tape surgery." J Obstet Gynaecol Res. 2014 Jun;40(6):1764-9.

Simsek A, Kirecci SL, Kucuktopcu O, Ozgor F, Akbulut MF, Sarilar O, Ozkuvanci U, Gurbuz ZG. "Comparison of paroxetine and dapoxetine, a novel selective serotonin reuptake inhibitor in the treatment of premature ejaculation." Asian J Androl. 2014 Sep-Oct;16(5):725-7.

Akbulut F, Kucuktopcu O, Sonmezay E, Simsek A, Ozgor F, Gurbuz ZG. "Partial penectomy after debridement of a Fournier's gangrene progressing with an isolated penile necrosis." Ulus Travma Acil Cerrahi Derg. 2014 Sep;20(5):385-8.

Simsek A, Ozgor F, Yuksel B, Kucuktopcu O, Kirecci SL, Toptas M, Sarilar O, Berberoglu AY, Gurbuz ZG, Mimaroglu S, Akbulut F, Baykal M, Arslan B, Savun M, Ucpinar B. "Female sexual function after transobturator tape in women with urodynamic stress urinary incontinence." Springerplus. 2014 Sep 30;3:570.

Akbulut F, Akman T, Salabas E, Dincer M, Ortac M, Kadioglu A. "Neurovascular bundle dissection for Nesbit procedure in congenital penile curvature patients: medial or lateral?" Asian J Androl. 2014 May-Jun;16(3):442-5.

Kadioglu A, Sanli O, Akman T, Canguven O, Aydin M, Akbulut F, Kucukdurmaz F. "Factors Affecting the Degree of Penile Deformity in Peyronie's Disease: An Analysis of 1001 Patients." J Androl. 2011 Sep-Oct;32(5):502-8.

Akman T, Sanli O, Uluocak N, Akbulut F, Nane I, Demir S, Kadioglu A. "The most commonly altered type of Peyronie's disease deformity under oral colchicine treatment is lateral curvature that mostly shifts to the dorsal side." Andrologia. 2011 Feb;43(1):28-33.

Akbulut MF, Sanli O, Kadioglu A. "Editorial Comment on: Are Infertile Men Less Healthy than Fertile Men? Results of a Prospective Case-Control Survey." Eur Urol. 2009 Dec;56(6):1032.

Acar O, Akinci M, Uluocak N, Akbulut F, Kilicaslan I, Gokce O. "Paratesticular metastasis of malignant melanoma: a case report." Kaohsiung J Med Sci. 2008 Jun;24(6):315-8.

Çubuk A, Erbin A, Savun M, Ayranci A, Üçpınar B, Yanaral F, Sarılar Ö, Basal Ş, Akbulut MF. "Autologous transobturator midurethral sling." Turk J Urol. 2018 Dec 21;45(3):230-232.

Sarılar Ö, Özgör F, Küçüktopçu O, Uçpınar B, Akbulut MF, Savun M, Gürbüz ZG, Binbay M. "Is standard percutaneous nephrolithotomy still the standard treatment modality for renal stones less than three centimeters?" Turk J Urol. 2017 Jun;43(2):165-170.

Akbulut F, Savun M, Ucpinar B, Sahan M, Arslan B, Ozgor F, Simsek A, Berberoglu AY, Baykal M, Binbay M. "Duplicated Renal System with H Shaped Ureter: An Extraordinary Anomaly." Case Rep Urol. 2016;2016:4062515.

Akbulut F, Kucuktopcu O, Kandemir E, Sonmezay E, Simsek A, Ucpinar B, Ozgor F, Gurbuz G. "Comparison of efficacy of laser lithotripter with ultrasonic lithotripter in mini percutaneous nephrolithotomy." Arch Ital Urol Androl. 2016 Jan 14;87(4):276-9.

Ozgor F, Simsek A, Aydogdu O, Kucuktopcu O, Sarilar O, Berberoglu AY, Akbulut MF, Binbay M. "Bleeding during laparoscopic partial nephrectomy: Can a hemostatic matrix help to improve hemostasis?"

Areas of Expertise and Interest

• Urological Cancers (Robotic and Laparoscopic Surgery)
• Stone diseases
• Benign prostate hyperplasia
• Minimally invasive prostate treatments (HoLEP, TuLEP, Rezum, TUR-P,..)
• Kidney Diseases
• Prostate Diseases
• Bladder Diseases
• Testis Diseases
• Sexual Dysfunctions - Infertility
• Infections

Education

• Bachelor's / Master's Degree: Faculty of Medicine, Istanbul University, 2006
• PhD: Urology, Bezmialem Vakıf University, 2012

Professional and Observational Experience in Medicine

• Research Assistant, Istanbul University, Istanbul Faculty of Medicine, Department of Anatomy, 10/2006 - 03/2007
• Research Assistant, Bezmialem Valide Sultan Foundation Gureba Training and Research Hospital, Urology Clinic, 08/2007 - 10/2010
• Research Assistant, Bezmialem University, Department of Urology, 10/2010 - 08/2012
• Observer, University of Michigan, Department of Urology, Ann Arbor, MI, USA, 05/2011 - 06/2011
• Specialist, Idil State Hospital, Idil, Şırnak, 11/2012 - 08/2014
• Specialist, Giresun Dr. A. İlhan Özdemir State Hospital, Giresun, 09/2014 - 2015
• Associate Professor, Bezmialem Vakıf University, Department of Urology, 2015 - 2024
• Associate Professor, Medipol Acıbadem Regional Hospital, 2024 - Present

Awards Received

• Effects of Sildenafil Citrate and Serotonin Reuptake Inhibitors on the Expression of Inducible Nitric Oxide Synthase, Endothelial Nitric Oxide Synthase, Neuronal Nitric Oxide Synthase, and Hypoxia-Inducible Factor-1 Alpha in Pulmonary Hypertension-Induced Rat Cavernous Tissues. Ilbey Y.Ö, Şimşek A, Özcan L, Cilli M, Polat E.C, Ersöz C, Somay A, Özbek E. 8th National Andrology Congress (International Participation), İzmir, Turkey, May 20-23. Congress Abstract Book; 22: SS-01 (2009). (Male Sexual Health Alpay Kelami Award)
• Extraperitoneal (EXPERT-ONOL) Sacrocolpopexy in the Treatment of Advanced Uterovaginal and Vaginal Prolapse: Intermediate-Term Results. Önol Ş.Y, Armağan A, Tepeler A, Başıbüyük İ, Ersöz C, Erdem M.R. 22nd National Urology Congress (International Participation), Girne, Turkish Republic of Northern Cyprus, May 02-06. Congress Abstract Book, 369: V-021 (2012).

Certificates

• Prof. Cevper Ersöz has over 130 national and international publications.

Memberships in Scientific Organizations

• Turkish Urology Association
• Turkish Pediatric Urology Association
• Turkish Endourology Association
• European Association of Urology (EAU)
• European Society of Endourology

Education and Experience

Dr. Ramazan Gökhan Atış, born in Istanbul in 1978, graduated from Cağaloğlu Anatolian High School in 1996. He completed his medical education at Çapa Faculty of Medicine in 2002. Between 2002 and 2008, he received his specialization training at the Istanbul Şişli Etfal Training and Research Hospital Department of Urology, and obtained the title of Urology Specialist in February 2008. After working at Edremit Military Hospital between 2008 and 2009, he started working as a Urology specialist at Istanbul Göztepe Training and Research Hospital in 2009. In 2011, he underwent a 3-month Laparoscopy-Robotic Urology training at Heidelberg University Heillbronn Clinic. Between 2009 and 2014, he conducted numerous scientific research studies, especially in the field of endourology, and obtained the title of Associate Professor in September 2014. In 2017, he was elected as a board member of the Endourology Society and has been serving in this position since then. Since 2018, he has been actively involved in the Endourology working group of the European Association of Urology, Young Academic Urologists (EAU-YAU) Committee for a period of 2 years. In January 2021, he was appointed as a Professor at the Istanbul Medeniyet University Department of Urology.After that started working at Şişli Memorial Hospital in 2022. Prof. Dr. Ramazan Gökhan Atış, has more than 100 articles published in national and international journals.

• 1996 - 2002, Istanbul University Istanbul Faculty of Medicine, Undergraduate
• 2002 - 2008, Şişli Etfal Training and Research Hospital/Istanbul, Specialization in Medicine
• 2014, Istanbul Medeniyet University Goztepe Training and Research Hospital, Associate Professorship
• 2021, Istanbul Medeniyet University Department of Urology, Professorship

Administrative Duties

• Editor of Endourology Bulletin
• Board Member of Endourology Society (Secretary General)

Memberships in Scientific Organizations

• Turkish Urology Association
• Turkish Endourology Association
• Turkish Andrology Association
• Eurasian Urooncology Association
• Turkish Medical Association

Education :

University: School of Medicine (English), Marmara University, 1989-1997

Residency: Urology / Urology Clinic, Dr Lütfü Kırdar Kartal Training and Research Hospital 1998-2003

Medical Specialty Thesis and Supervisors: The Role of Nerve Growth Factor in Bladder Outflow Obstruction, Assoc. Prof. Uğur Kuyumcuoğlu, M.D.

Assoc. Prof.: Urology Clinic, Dr Lütfü Kırdar Kartal Training and Research Hospital 2013

Biography :

Resident / Dr. Lütfi Kırdar Kartal Training and Research Hospital (1998 – 2003)

• Army Physician / Sarıkamış 200-Bed Military Hospital (2003-2004)

• Chief Resident / Dr. Lütfi Kırdar Kartal Training and Research Hospital (2004 – 2017)

• Physician / Aydın Atatürk State Hospital (2017)

• Physician / Kocaeli Acıbadem Hospital (2017-2018)

• Physician / Adatıp Hospital (2018-…)

Area of Specialty :

İçerik Yazınız

Memberships :

Turkish Association of Urologic Surgery

Turkish Association of Urology

Turkish Association of Andrology

Society of Endourology

Urooncology Association

Turkish Medical Association