Norman H. Dubin

The inhibition of premature labor with indomethacin

We administered indomethacin orally for the treatment of premature labor in a prospective, randomized, double-blind fashion, and all infants were followed up. Indomethacin was significantly more effective than placebo in inhibition of premature labor during a 24-hour course of therapy, with treatment failure during therapy occurring in only one of 15 indomethacin-treated patients compared to nine of 15 placebo-treated patients (p less than 0.01). Mean plasma concentrations of indomethacin were approximately 0.8 micrograms/ml at both 4 and 12 hours after administration. Mean plasma levels of 15-oxo-13,14-dihydroprostaglandin F2 alpha (PGFM) were similar in the two groups before treatment, decreased markedly in the indomethacin group by 4 hours, and were not detected at 12 hours in all but the one indomethacin-treated patient who was delivered within 24 hours. Patients in the placebo group who were delivered prematurely had higher pretreatment PGFM levels (mean +/- SE, 83 +/- 18 pg/ml, n = 9) than the patients who responded to placebo (25 +/- 6 pg/ml, n = 6) (p less than 0.05). There was no difference between the indomethacin and placebo groups with respect to gestational age at delivery, birth weight, and neonatal morbidity and deaths. In particular, we found no evidence of premature closure of the ductus arteriosus, pulmonary hypertension, or increase in bleeding problems among the infants exposed to indomethacin in utero. Although no difference in neonatal outcome was observed in this small number of patients, it would seem prudent still to consider indomethacin as an experimental therapy.

The rate at which human sperm are immobilized and killed by mild acidity.

OBJECTIVE To determine the rate at which mild acidity immobilizes and kills human sperm and to evaluate an acidic microbicide, BufferGel, for sperm immobilization. DESIGN Controlled in vitro study. SETTING An academic research university and hospital andrology lab. PATIENT(S) Eight volunteer male sperm donors. INTERVENTION(S) Semen samples were treated with hydrochloric acid (HCl) or BufferGel. MAIN OUTCOME MEASURE(S) Sperm motility was measured by using a computerized automated semen analyzer and video microscopy. Sperm membrane permeability and intracellular pH were measured by using fluorescent techniques. RESULT(S) In semen acidified with HCl to pH 4.0, sperm were rapidly immobilized (within 1 min) and were irreversibly immobilized (killed) within 10 minutes. The speed of immobilization and of killing were both linearly proportional to hydrogen ion activity over a pH range of 7.5-4.0. Across the same range, the intracellular pH of human sperm equilibrated to within 0.5 pH units of extracellular pH within 1-2 minutes. BufferGel immobilized sperm significantly faster than HCl from pH 4.0-6.0. CONCLUSION(S) Exposure to mild acidity rapidly acidifies the intracellular pH of human sperm and is rapidly spermicidal. BufferGel accelerates acid immobilization of sperm.

Cul-de-sac fluid in women with endometriosis: fluid volume and prostanoid concentration during the proliferative phase of the cycle—days 8 to 12 *

Cul-de-sac fluid from women with histologically confirmed endometriosis (n = 45) or with no evidence of endometriosis (n = 17) was removed during the proliferative phase of the menstrual cycle (days 8 to 12) and analyzed for prostaglandin E2 (PGE2), prostaglandin F2 alpha (PGF2 alpha), 15-keto-13,14-dihydroprostaglandin F2 alpha (PGFM), and thromboxane B2 (TXB2). The fluid volume was recorded. Peripheral blood was also obtained to determine the concentration of PGFM. Prostanoid concentrations (PGE2, PGF2 alpha, PGFM, TXB2) in women with endometriosis were not significantly different from a comparable group of disease-free women. Furthermore, a meaningful elevation of prostanoid with increasing severity of disease could not be demonstrated. Plasma PGFM was not significantly different from controls. There was, however, an elevation of PGFM with severity of disease, although this increase was not statistically significant (P = 0.11). An increase in fluid volume was not demonstrated in women with endometriosis, as compared with controls.

13, 14-Dihydro-15-keto-prostaglandin F2α concentrations in human plasma and amniotic fluid

An antiserum to 13,14-dihydro-15-keto-prostaglandin F2alpha (PGF2alphaM) was prepared and a radioimmunoassay evaluated in various reproductive states. PGF2alphaM plasma concentration was 63.6 +/- 10.3 pg/ml (mean +/- SEM) in cycling women. The concentration fluctuated throughout the menstrual cycle and pregnancy, but no discernible patterns were noted. PGF2alphaM concentrations were elevated at the time of urea + oxytocin induced abortion (238 +/- 54 pg/ml) and during late stages of normal labor (352 +/- 107 pg/ml) but were not elevated during labor prior to 7 cm dilatation. Following intra-amniotic instillation of 5 mg of PGF2alpha tromethamine into the amniotic sac, PGF2alphaM concentration increased in the amniotic fluid. In the plasma of these patients there was an eighteenfold rise in plasma PGF2alphaM concentration compared to a 3.5-fold rise in PGF2alpha at 1 hour, suggesting changes in PGF2alphaM may be more easily detected than the parent compound. While PGF2alphaM may be a useful index of PGF2alpha production, it appears that PGF2alphaM is of little value in predicting the occurrence of uterine contraction.

Inhibition of fetal membrane prostaglandin production by prolactin: Relative importance in the initiation of labor

Production of a biologically active prolactin by human decidual tissue and its influence on the permeability of amniochorion to water suggests a functional relationship between the polypeptide and fetal membrane metabolism. Under in vitro circumstances, we used ovine prolactin and the Ussing chamber technique to determine the role of prolactin in prostaglandin E2 production by human fetal membrane. Fresh reflected membranes obtained from elective cesarean sections were exposed to ovine prolactin (10 micrograms/ml). Aliquots of incubation media were sampled at 0, 30, 60, 120, and 240 minutes, quick-frozen, and later assayed for prostaglandin E2. Multifactorial analysis of variance revealed that ovine prolactin significantly reduced prostaglandin E2 production (f = 13.42, p less than 0.005). Prostaglandin E2 output was greatest by amnion (3581 +/- 596 pg/ml/gm declining to 1819 +/- 452 pg/ml/gm during 4 hours). Other combinations of fetal membranes including amnion-chorion-decidua produced only 12% to 15% prostaglandin E2 per gram compared with that produced by amnion alone. Those membranes similarly responded to prolactin with a reduction in prostaglandin E2 output of 34% to 59%. Correlation analysis identified a significant relationship between prostaglandin E2 production and time (r = 0.298; p less than 0.001), which was abolished by ovine prolactin (r = 0.115, p greater than 0.10). This model illustrates that ovine prolactin modifies the production of prostaglandin by fetal membranes in vitro. By analogy, endogenous prolactin by human decidual tissue might also inhibit the elaboration of prostaglandin E2 from its precursors residing within the fetal membranes.

Pharmacokinetic studies on quinacrine following intrauterine administration to cynomolgus monkeys

Recent efforts have been made to develop a chemical oviductal occluding agent. Intrauterine quinacrine has been used in certain areas of the world with moderate success in effected tubal closure. This report presents the pharmacokinetics of a quinacrine solution (30 mg) as administered to cynomolgus monkeys via the intrauterine route, compared with intravascular injection. The data show rapid transfer of the drug from the uterine to the vascular compartment and uptake by almost all tissues examined. Although plasma concentrations disappear within 24 hours, levels can be detected in most tissues for at least 1 week following intrauterine injection. After 28 days, however, tissue levels of the drug are absent or near the limit of detection.

Hormonal considerations in early normal pregnancy and blighted ovum syndrome.

The hormonal profiles of six pregnancies which terminated in miscarriage with the blighted ovum syndrome have been studied and compared with those of a group of patients similarly studied who had clinically normal pregnancies terminating in live birth at term. The serum chorionic gonadotropin (HCG) values were below normal or at the lowest limit of normal in five of six patients. Three patients had progesterone values within 1 SD of the normal, with normal serum estradiol values. It was concluded that the hormonal profile of early pregnancy is characterized by rising serum HCG and estradiol levels and a declining serum progesterone level from the 5th to the 8th week. The theoretical explanation for the dichotomy seems to be that the fetal adrenal anlagen, even at this early embryonic stage, can produce steroid precursors which are aromatized to estradiol. The production of progesterone, however, does not seem to be possible. Abnormal serum estradiol levels strongly suggest the absence of fetal development and a blighted ovum. However, no single hormonal level will distinguish between blighted ovum and potentially salvagable threatened abortion.

Effect of intrauterine and intravascular quinacrine administration on histopathology, blood chemistry, and hematology in cynomolgus monkeys.

Histopathologic features, blood chemistry, and hematologic features were studied in cynomolgus monkeys following intravascular or intrauterine administration of a 30-mg solution of quinacrine hydrochloride. Intrauterine quinacrine administration resulted in extensive necrosis of the endometrial surface, and lesions were observed at 24 hours after treatment which obliterated the cornual areas of the uterus. Necrosis was also observed on occasion in the ampulla or isthmic portion of the tube. Evidence of repair of the reproductive tract was seen 7 and 28 days following treatment. No lesions were observed in any nonreproductive organ examined, whether quinacrine was administered by the intrauterine or intravascular route. Blood chemistry data revealed moderate and transient increases in serum glutamic oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), and lactic dehydrogenase (LDH). No other blood chemistry or hematologic changes were noted that could be attributed to quinacrine administration. For the conditions described in these studies, intrauterine administration of quinacrine appears to be a safe procedure. However, the potential toxicity of the drug is discussed.

Prostaglandin E2 release on the fetal and maternal sides of the amnion and chorion-decidua before and after term labor

Release of prostaglandin E2 on each of the fetal and maternal sides of the fetal membranes (8 cm2) from term cesarean (no labor) and spontaneous vaginal (labor) deliveries was studied with the use of dual-compartment perfusion chambers. Postlabor amnion released significantly (p less than 0.05) more total prostaglandin E2 (5.66 +/- 1.02 ng, mean +/- SEM) than prelabor tissue (3.34 +/- 1.76 ng) with equivalent prostaglandin E2 levels being released on both sides. A net decrease (p less than 0.001) in prostaglandin E2 release by chorion-decidua was identified after labor (fetal = 0.12 +/- 0.05 ng; maternal = 0.17 +/- 0.09 ng) when compared with that before labor (fetal = 1.28 +/- 0.69 ng; maternal = 2.31 +/- 0.56 ng). Amnion-chorion-decidua released more prostaglandin E2 on the fetal side after labor (2.37 +/- 1.43 ng) than prior to labor (1.49 +/- 0.60 ng); however, prostaglandin E2 on the maternal side was significantly less (p less than 0.05) after labor (0.24 +/- 0.12 ng) when compared with that of the prelabor membrane (2.03 +/- 1.08 ng). Elution of prostaglandin E2 from preincubated membranes and endogenous membrane prostaglandin E2 content showed similar results. Thus concentrations of prostaglandin E2 on the maternal side of the fetal membranes appear diminished after spontaneous labor despite an increased release from the fetal surface.

Effect of hydrogen peroxide on prostaglandin production and contractions of the pregnant rat uterus

Although evidence for a role for prostaglandins in parturition is abundant, less is known about how prostaglandin levels are regulated at term. Conditions occurring peripartum in the uteroplacental unit can result in reactive oxygen production. We investigated the effect of one reactive oxygen product, hydrogen peroxide, on in vitro activity of uterine segments from the 18-day-pregnant rat. H2O2 (0.3 mmol/L) was found to elicit rhythmic contractions and increase prostaglandins F2 alpha and E2 release by uterine tissue. Indomethacin blocked both of these effects. We conclude that H2O2 stimulates uterine contractions through a prostaglandin release mechanism. A speculative hypothesis of peripartum regulation of prostaglandin production by reactive oxygen is discussed.