Arginine vasopressin V1a receptor gene expression in human fetal membranes

MEMBRANES FATANEH AMIDI, SHENGBIAO WANG, NIMRA CHAUDHRI, MARIE BEALL, MICHAEL ROSS, Harbor-UCLA Med. Ctr., Dept. of OB/GYN (LA BioMed), Torrance, California OBJECTIVE: The intramembranous (IM) pathway plays an important role in amniotic fluid (AF) volume regulation. Though the molecular and cellular mechanisms of IM water absorption are not yet understood, aquaporin (AQP) water channels are present on human fetal membranes. In the kidney, AQP channel expression increases in response to arginine vasopressin (AVP), facilitating renal water resorption. AVP is present in human fetal urine and AF, and increases significantly in response to fetal hypoxia. We hypothesize that fetal stress-induced increases in AF AVP upregulates chorioamnion AQP, thereby increasing IM water resorption and reducing AF volume. To assess potential sites of AVP action, we determined if AVP V1a and V1b receptors are expressed in human fetal membranes. STUDY DESIGN: Immediately following elective cesarean section delivery, human amnion, chorion and placenta of normal term pregnancies were dissected and frozen in liquid nitrogen. Total RNA was isolated and reverse transcriptasepolymerase chain reaction (RT-PCR) was used to determine V1a and V1b mRNA expression. Immunohistochemical staining with anti-V1a receptor antibody was employed to localize V1a receptor protein in these human fetal membranes. RESULTS: RT-PCR detected V1a mRNA in amnion, chorion and placenta. No V1b mRNA was detected in these tissues by RT-PCR, the most sensitive method for gene expression detection. Immunohistochemical study demonstrated the V1a protein expression in epithelia of amnion, chorion and placental trophoblasts. CONCLUSION: These results demonstrate both mRNA and protein expression of V1a receptor in human chorioamniotic membranes and placenta. AVPmediated upregulation of AQPs, may alter water absorption across the chorioamniotic membranes and AF volume homeostasis. 538 A CRITICAL CARE MEDICINE CURRICULUM FOR MFM FELLOWS LAUREN PLANTE, University of New Mexico, Obstetrics & Gynecology, Albuquerque, New Mexico OBJECTIVE: To describe and evaluate a year-long program designed to teach fundamentals of critical care medicine in the context of a maternal-fetal medicine fellowship. This program, with lectures, Web-based learning, and hands-on training focused on a high-fidelity patient simulator, is a step in creating a cadre of providers who are comfortable and competent in caring for critically ill obstetric patients. STUDY DESIGN: A pretest was administered to MFM fellows to assess fundamental critical care knowledge; questions were drawn from standardized materials of the Society for Critical Care Medicine (SCCM). Subsequently, they were enrolled in a critical care medicine curriculum which included: ACLS certification, participation in the Pulmonary Artery Catheter Education Program, (www.pacep.org), lectures covering core topics from the SCCM Guidelines for Resident Education, and clinical scenarios in the human simulator lab. At the completion of the year, a post-test was administered. Participants rated the program. RESULTS: Median test scores improved from 30% to 69%. Fellows rated the curriculum highly and professed themselves more comfortable with the care of critically ill obstetric patients. CONCLUSION: Neither obstetricians nor intensivists have been ideally suited to care for obstetrical patients in an ICU. Although critical care fellowships are open to obstetricians, few avail themselves of the option as it requires an additional 1-3 years. Nonetheless, some expertise must be acquired if perinatologists are to contribute to the care of these patients: we cannot simply turn them over to our intensivist colleagues. This program, incorporating critical care medicine training within an MFM fellowship, appears promising. Reliance on simulator technology to train in critical scenarios allows fellows to acquire highstakes skills in a low-stakes situation, and to rehearse behaviors, decisionmaking, procedures, and team management. The simulator also allows acquisition of skills which otherwise may prove difficult to obtain, given the rarity of OB ICU admissions.