217 Effects of Prostaglandins and Thromboxanes on Endothelin-1 (ET-1) Induced Vasoconstriction of Human Placenta

217 Effects of Prostaglandins and Thromboxanes on Endothelin-1 (ET-1) Induced Vasoconstriction of Human Placenta

358 214 SPO Abstracts INHIBITION OF DECIDUAL PROLACTIN SECRETION BY CHOUNESTERASE IN VITRO. ~, T.R.B. Johnson, H.A. Zacu"', Dept. of GYN/OB, Johns ...

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SPO Abstracts

INHIBITION OF DECIDUAL PROLACTIN SECRETION BY CHOUNESTERASE IN VITRO. ~, T.R.B. Johnson, H.A. Zacu"', Dept. of GYN/OB, Johns Hopkins University School of Medicine, Baltimore, MD 21287 OBJECTIVE: Cocaine use in pregnancy has been implicated in incraasing the risk of premature labor. We hypothesized that this effect might be mediated by a change in decidual prolactin secretion. From previous 8tudies, we reported a rise in the prolactin concentration of media bathing human decidual tissue following addition of cocaine (SPO abstract #367, 1992). Since cocaine is hydrolyzed by cholinesterase (ChE) in vivo, we sought to determine if ChE wes required to produce this effect. STUDY DESIGN: Fresh fetal membranes with attached decidual tissues were obtained at term during elective cesarean section (n = 2) and placed in 6 cc. of Gey'. buffer, pH 7.4 with varied concentrations of ChE elone (0,1,10,100,200 units/mil or cocaine (0, 10-°, 10-0 , 104M) with ChE (200 units/mil in a 5% CO2 , 95% air humidified incubator at 37'C for 24 hours. At intervals (1.4,24 hrs), a 0.6 ml aliquot of culture medium was taken and the prolactin concentration determined by enzyme immunoassay. RESULTS: Media prolactin concentrations did not increase rapidly during the first four hours of incubation when cocaine and ChE were addad together or when ChE was given alone. Media prolactin concentrations during the first four hours of incubation we'e inversely correlated with ChE concentrations. From 4 to 24 hours of incubation, media prolactin concentrations gradually rose. Media prolactin concentrations were higher when decidua was incubated with cocaine end ChE in comparison to ChE alone, confirming our previous observation of e stimulating effect of cocaine. CONCLUSIONS: Cholinesterase markedly suppressed decidual prolactin secretion in a dose dependent manner. This suggests 8 previously unrecognized role of cholinesterase in the regulation of decidual prolactin secretion.

215 COLLECTION

AND GROWTH OF CORD BLOOD PROGENITOR CELLS IN SERUM-FREE MEDIA. R. Comenzo', C. Cetrulo, M. Malachowski', E.M. Berkman'. New England Medical Center and University Hospital, Boston, MA. OBJECTIVE: To assess progenitor cells in cord blood mononuclear cell (MNC) collections using a serum-free assay. STUDY DESIGN: Cord blood samples were collected in RPMI+2S00 U heparin and lightdensity (LD) MNC were separated over FicollPague. Cultures were performed in IMDMbased methylcellulose medium with 1\ human albumin and recombinant human cytokines: EPO (3U/ml), IL-3 (SOOU/ml), GM-CSF (SOOU/ml) and stem cell factor (100 ng/ml), and were scored by standard criteria as erythroid, myeloid or mixed colonies after 14 days of incubation at 37 deg C in S\ C~ and high humidity. RESULTS: Mean LDMNC (N=3) were 1.1+/-0.3 x 10· per collection in 52 +/-31 m1. Mean total erythroid, myeloid and mixed colonies were 1.1, 1.7 and 0.2 x 10' respectively. Mean progenitor (colony-forming) fraction was 0.2S\ of LDMNC. CONCLUSIONS: Hematopoietic progenitor cells in cord blood MNC are present in large numbers and can be assayed with serum-free media. Cord blood MNC represent a potential source of stem cells for bone marrow transplantation.

January 1993 Am J Obstet Gynecol

216 HECHANISHS OF RELAXATION OF PLACENTAL VESSELS TO

LACTATE & ~02' R.Fiqueroa, H.OmarI, N.Tejani, M. WOlinI • Depts. Physiol. &ObGyn, NYMC, Valhalla, NY. OBJECTIVES: To determine whether lactate (L) + H.,02 cause relaxation via cGMP mediation in placental vessels. STUDY DESIGN: Isolated placental vessels (1-2 mm diameter, from normal term pregnancies) incubated under 5%02' and precontracted with 1-3):JM PGF2a, were exposed to L (1-10mM) or H202 (1):JM1mM+101lM indomethacin) in the presence & absence of hypoxia (P02 8-10torr), 10):JM methylene blue (MB, inhibits guanylate cyclase (GC) stimulation), 1mM cyanide (CN,inhibits GC stimulation by ~O) and nitroglycerin (NTG) & forskolin (F), which are agents that produce relaxation via stimulation of GC by nitric oxide and adenylate cyclase. ANOVA statistics were used. RESULTS: Relaxation to L was markedly (p<0.05, n=5) suppressed by hypoxia(90%), by MB(64-90%) and by CN(67-97%). Relaxation to HP2 (p<0.05, n=5) was suppressed by MB(60%) & CN(70%) but not by hypoxia. Relaxation to NTG (p<0.05, n=5) was suppressed by MB(77%) but not by hypoxia or CN. None of these agents inhibited relaxation to F. CONCLUSIONS: Placental vessels: l)show a cGMPmediated relaxation to L and H202 consistent with an H202 involved mediation; 2)possess both cGMP & cAMP mediated relaxing mechanisms.

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ElI'FECTS 011' PROSTAGLANDINS AND THROMBOXANKS ON ENDOTHELlN-l (KT-l) INDUCED VASOCONSTRICTION 011' HUMAN PLACENTA. S. O. Le". N. W-*Dm, J.V. MElbouli". P.M. VanhouUe". Dept ObiGyn IBld Medicine. & Ctr Exp 'lber. Baylor eon Med. HoUlllon, TX. OBJJ:CTIVII:: We have recenIly found th& e:ndothelin-l (ET-1) is a potent cOlllllrictor of placental veaels. The present ItUdy II01Jgbt to detennine the extent to which protiglsncIinB IBld thromboXllllea conIribuIe to ET-1 induced placenlal VIIBOCOIIIlIriction. STUDY DESIGN: InunedilteJ.y after wgi.nal delivery of uncomplicllled human pregnanciel, veins of the chorionic plate were m-:ted ftee (n=8). divided into ri:ngI and mounted in perl'oIed tiaue chambers. Following a period of Illllhili7J!ljon at optimal basal tension, i&omeIric tensiOllll in the control group were IeCOrded at increasing dOIeII ofET-l ( 10-" to 10-' M). RingII in the experimental group. were pretreated with either indomethacin (pro&tagIandin IYJIlhetaIe inhibitor.lO" M). dazoxibe:n (thromboxane Ii}'lItheIaIe inhibitor. 10"' M). or SQ29S48 (thrombollllM receptor IDIr8oniIt. 10" M). prior to addition of ET-1. The conceDl.alion-IeIpOfI88 curvea of the treated and control ~ _ compared 1IIin& Student'. paired t-ts.. RESULTS: ET-l CIIIIMd COIIlradiOIIII of the pIacenIal veins. Indomethacin ~ reduced the COIIlradiOIIII to low concentrIiDonII (10" M or lea) ofET-1 (p<.OS). The eft'edII of dazoxiben and SQ29S48 on ET-1 induced cOllltridion were variable and were not IIIaIiItiaIIly IIignificant. CONCLUSIONS: In human placenlal veaU. ET-1'1 VIIIIOCOIIIItri action ill J1lOCluhUd by proIII8g1andins. However. it doeI not appear to depend on thromboxane.