352 SPO Abstracts

268 FETAL INTRACARDIAC KCL WITH SECOND TRIIIIESTER PREGNANCY TERMINATION: A METHOD TO AVOID THE HOPELESS RESUSCITATION OF THE NONVIABLE, ABNORMAL ABORTUS. ~, JC Fletcher, MP Johnson, WB Blessed, MI Evans. Division of Reproductive Genetics, Dept Ob/Gyn, Hutzel Hosp/WSU, Detroit, Mi and The Center for Biomedical Ethics, Dept Medicine, U Virginia, Charlottesville, Va.

269

Genetic and obstetric ultrasound services often reveal anomalous fetuses which, after counseling, parents choose to terminate. However, an increasing number of centers will not perform pregnancy terminations after 20 wks, in part because of the chance of obtaining a "live born" neonate. In a few cases, 2nd trimester abortion has resulted in the birth of a neonate with signs of life, even with utilization of intraamniotic urea. Pediatricians are put in an impossible position and may feel obligated to attempt full resuscitative efforts. Because this has happened in our institution, we have introduced fetal intracardiac potaSSium chloride (KCI) as a routine adjunctive procedure based on our experience with this method in moltifetal pregnancy reductions. Under ultrasound guidance, a 22-gauge needle is directed into the fetal cardiac chambers. Proper placement is verified by blood return. Three to five cc of KCI (2 meqlml) is instilled. Cessation of cardiac motion is verified with M-mode scanning. This approach was successful in causing rapid fetal cardiac arrest in 14 out of 15 cases. A decision to use intracardiac KCI avoids some of the ethical and legal quagmires that arise when the abnormal abortus­newborn has signs of life, and can be readily introduced into programs where invasive perinatal procedures are performed.

NEIIlOTOXIC EFFECTS OF LEAD ON HYPOTHALAMIC OOPAMINERGIC NEURONS. S. Ramin. W. Kedzierski~ J. Porter,X Dept. Ob/Gyn, Univ. Texas Southwestern Med. Ctr .. Oa llas, TX

We invest igated the neurotoxic effects of lead in primary cultures of hypothalamic cells from 18 to 22 day gestation Long­Evans rat fetuses. Two week old cell cultures were treated with various levels of lead nitrate for 24 h. Then, the medium was collected. acidified. and assayed for dopamine (DA) and dihydroxyphenylalanine (DOPA) by HPLC with electro-chemical detection. DOPA secretion is sumnarized below:

Lead DOPA (pmol/well/24 h)

Cone. 18 Days 20 Days 22 Days

Contra 1 17.2±1.5 32.4±1.9 36.2±2.7 Ixl0- 1OM 8.5±0.4 19.7±1.0 30.7±0.9 Ixl0- 9M 9. 3±0. 3 23. 3±1. 5 31. 8±0. 6 IxIO- 8M 10.6±0.6 22. 6±0. 8 30. 2±1. a IxIO- 7M 10.0±0.3 22.7±0.6 36.8±3.0 IxIO- 6M 10.7±0.4 24.8±1.2 36.5±2.2 IxIO- SM 10.1±1.0 28.8±0.7 38.9±0.6 IxIO- 4M 19.3±0.7 39.1±1.7 50.1±1.1 Ixl0- 3M 22. 8±0. 4 42.9±1.0 54.4±2.4 n=3-5 DA secretion follows the same pattern. At low levels of lead, DOPA and DA secretion are inhibited, whereas at high levels DOPA and DA secretion are stimulated. However. the inhibition with lead is more pronounced on cells from younger fetuses than it is from older fetuses. Conversely, the stimulation with lead is more pronounced on cells from older fetuses than it is from younger fetuses. The same pattern is seen with long term (two weeks) exposure of cu ltured ce 11s to lead n; trate. These data suggest that the neurotoxic effects of lead may depend in part on the age of the fetus at the time of exposure.

January 1992 Am J Obstet Gynecol

270 METHAMPHETAMINE USE DURING PREGNANCY IN A LARGE URBAN POPULATION. S.M. Ramin, M.D., B.B. Little, Ph.D.: K.J. Trimmer, M.D., D.1. Standard, B.S.: C.A. Blakely, Ph.D.: & L.M. Snell, M.P.H. + Depts. of Ob/Gyn & Fam. Prac. & Comm. Med., The Univ. of Texas Southwestern Med. Ctr., Dallas, Tx., PPRL, Texas A & M, College Station, Tx.

271

A paucity of information exists on effects of meth­amphetamine (MA) use during pregnancy and fetal outcome. Umbilical cord blood was collected from 863 consecutive births at two large urban public hospitals serving a primarily indigent population. Radioimmunoassay was used to test for the presence of MA. Medical record information was linked to serological analyses. Patients positive for other drugs (opiates, cocaine, alcohol, toluene) were excluded. Results are summarized below. MA Control

Birth weight (gm) Birth length (em) Head ci rCLITlfprence (em) Apgar: 1 minute

5 minute EGA (weeks)

Major anomalies Minor anomalies

(n=48) (n=519) Mean SE Mean SE P 3173 69 3327 18 0.03 49.4 0.4 49.3 0.1 NS 33.7 0.3 33.8 0.1 NS 8.4 0.1 8.6 0.1 NS 8.8 0.1 8.9 0.1 NS

38.6 0.3 38.8 0.1 NS N % N %

T "'4 II "'4 NS 1 2 42 6 NS

These results are similar to those previously published for MA use during pregnancy by self-reported history. Although a reduction in birth weight was found in the MA group, the frequency of congenital anomalies was not increased compared to the control group.

APPLICATION OF MOLECULAR CYTOGENETICS TO UNCULTURED FIRST TRIMESTER CHORIONIC VILLI. K. Blakemore, G. Prabhakar,' G. Stattan,' R_ Giraldez,' F. Marcus,' W. Chen.' The Johns Hopkins University School of Medicine, Baltimore, MD.

The clinical utility of fkJorescent ctvomo8ome-specific centromere probea he. been shown on interpheea amniocytea and blood cells. We describe a method for use of these DNA probes on interphese nuclei from a solid tissue, chorionic villi. "Direct" preparations of uncultured v~lua calla ware made by the method of Simoni et al. (1983), with and without 24 hr incubetion, Coleemid exposura, and heat drying of slides. Fluorescence in situ hybridization was performad bV the mat hod of Pinkal at al. (1986) with minor modification. 20 ng of biotinvlated probe DYZ3, DXZl or D9Z1 (ONCOR, Inc.) was added to a hybridization mixture (60% formamida/2X SSC), 10 pi of which was applied to each slide followed by heat denaturation (80DC for 6 min). Slides ware incubated overnight at 42DC, and washed (60% formamida/2X SSC at room temp). The probe was detected with FITC conjugated avidin. Preparations were counterstained with propidium iodide (0.4I1g/ml) and examined using a Zeiss epifluoresce microscope. A clearer signsl was obtained when slides ware air dried. Omitting the 24 hr incubation and Coleemid exposure of the villi did not alter signal quality. Three cases illustrate the utility of this method: Case 1, st risk for the fragile X syndrome, to rapidly determine fetal sex; Case 2, a blightad ovum in a patient with two previous conceptuses, to demonstrate yet another recurrence; and Case 3, in which mosaicism for trisomy 9 was found on routine cytogenetic anelysis of cultured villi, to examine the proponion of abnormal cells in direct villus metaphases and interphese nuclei. Fluorescence in situ hybridization is a valuable new tool for rapid identification of fetal sex chromosomes end specific trisomies in prenatal diagnosis. First trimester re.utt. are possible using call preparations made from chorionic villus tissue.