Medical Student Research Fellowship for Summer 2008

Mentor: Charles Quinn, M.D.
Department: Pediatrics, Pediatric Hematology-Oncology
Room number: G3.232
Mail Code: 9063
Phone number: 214-648-3896
E-mail: charles.quinn@utsouthwestern.edu

Co-Mentor: Michael Dowling, M.D., Ph.D.
Department: Pediatrics, Pediatric Neurology
E-mail: michael.dowling@utsouthwestern.edu

Project title: Correlation of daytime oxyhemoglobin saturation with cerebral flow velocities in children with sickle cell anemia.
Human subjects IRB approved project number (where applicable): 0302-173
Animal subjects IRB approved project number (where applicable): N/A
Project Type: Patient-based research
Brief Description of Project:
Sickle cell anemia (Hgb SS) is the most common cause of stroke in children. Approximately 11% of children with Hgb SS will suffer a clinically overt stroke before their 18th birthday. There are a handful of known risk factors for stroke in Hgb SS, but our ability to predict stroke remains imperfect. The speed of blood flow through the large arteries at the base of the brain, measured by transcranial Doppler ultrasonography (TCD), is one of these risk factors for stroke. We studied the Dallas Newborn Cohort (1, 2), a large cohort of children with sickle cell disease, and recently found that daytime hemoglobin desaturation is also a risk factor for stroke (3). We would now like to extend this research to determine whether daytime hemoglobin desaturation is also associated with TCD velocities. We hypothesize the lower oxygen saturations will be associated with higher cerebral blood flow velocities, because a higher flow rate of desaturated blood will be needed to maintain oxygen delivery to the brain. If we can correlate oxygen saturation with an established risk factor for stroke, TCD velocity, this will strengthen our argument that saturation is, indeed, a risk factor for stroke. The physiologic link between the two measures also strengthens this argument. We have experience analyzing and publishing TCD data from children (4). This project will require the extraction of raw data from ~200 clinical TCD reports, the maintenance and organization of the data in a database, as well as analyzing the data and reporting the results.

1. Quinn CT, Rogers ZR, and Buchanan GR. Survival of children with sickle cell disease. Blood, 103:4023-4027, 2004.
2. Quinn CT and Ahmad N. Clinical correlates of steady-state oxyhaemoglobin desaturation in children who have sickle cell disease. Br J Haematol, 131:129-134, 2005.
3. Quinn CT and Sargent JW. Daytime steady-state haemoglobin desaturation is a risk factor for overt stroke in children with sickle cell anaemia. Br J Haematol, 140:336-339, 2008.
4. Jordan LC, Wityk RJ, Dowling MM, Comi AC. Transcranial doppler ultrasound in children with Sturge-Weber Syndrome. J Child Neurology, in press (epublished 12,3,3007 as doi:10.1177/0993073807307079)

Previous Research Activities or Publications with Medical Students:

2002: Angela Smith, medical student
Project: Burden of episodic transfusion in children with sickle cell anemia
Publication: Smith A, Quinn CT, Rogers ZR, Buchanan GR. Burden of episodic transfusion in children with sickle cell anemia. Blood 100:25b, 2002. (abstract)

2003: Chinelo Onuwekwusi, medical student
Project: Prognostic significance of early vaso-occlusive complications of sickle cell disease
Publication: Quinn CT, Onuekwusi C, Rogers ZR, and Buchanan GR. Hospitalization for Pain or Acute Chest Syndrome (ACS) in the First Three Years of Life Does Not Predict Subsequent Adverse Outcomes in Children with Sickle Cell Anemia. Pediatr Blood Cancer 42:496, 2004. (abstract)

2004: Yung-Ping Chin, medical student
Project: Prognostic significance of birth weight and red blood cell phenotype in sickle cell disease
Publication: Quinn CT, Chin Y-P, Ahmad N, Rogers ZR, Buchanan GR. Prognostic significance of birth weight and red blood cell phenotype in sickle cell disease. Blood 104:25b, 2004. (abstract)

2005: Nancy Lee, undergraduate student
Project: Update of the Dallas Newborn Cohort
Publication: Quinn CT, Lee NJ, Rogers ZR, Buchanan GR. Survival of children with sickle cell disease: an update from the Dallas Newborn Cohort. Blood 106:32b, 2005. (abstract)

2006: Nancy Lee, undergraduate student
Project: Validation of the CSSCD early prediction model
Publication: Quinn CT, Lee NJ, Shull EP, Ahmad N, Rogers ZR, Buchanan GR. Prediction of adverse outcomes in children with sickle cell disease: a report of the Dallas Newborn Cohort. Blood, 111:544-548, 2008.

2006: Jeff Waugh, medical student.
Project: Review of Pediatric patients with movement disorders
Publication: Waugh JL, Miller VS, Chudnow RS, Dowling MM. A case report of Juvenile Huntington Disease exacerbated by methylphenidate. J Child Neurology, in press.

2007: James Sargent, medical student
Project: Correlation of daytime oxyhemoglobin saturation with overt stroke in children with sickle cell anemia.
Publication: Quinn CT and Sargent JW. Daytime steady-state haemoglobin desaturation is a risk factor for overt stroke in children with sickle cell anaemia. Br J Haematol, 140:336-339, 2008.