Intra-amniotic Administration Research Articles

Factors Influencing Adenovirus-Mediated Airway Transduction in Fetal Mice

Intra-amniotic injection of adenovirus allows transduction of the fetal airways following natural fetal breathing movements. This administration method is promising for use in gene therapy for cystic fibrosis and other diseases for which the main target for exogenous gene expression is the lung. Here we have investigated factors that may affect the efficacy of gene transfer to the murine fetal lung. We examined marker compound distribution and transgene expression (from a first-generation adenoviral vector) at different stages of development. This demonstrated that fetal breathing movements at 15-16 days of gestation are of sufficient intensity to carry marker/vector into the fetal lungs. These movements can be significantly stimulated by the combination of intra-amniotic theophylline administration and postoperative exposure of the dam to elevated CO(2) levels. However, the most important factor for efficient and consistent pulmonary transgene delivery is the dose of adenoviral vector used, as both the degree of transduction and the percentage of lungs transduced increases with escalating viral dose.

Changes in chicken intestinal zinc exporter mRNA expression and small intestinal functionality following intra-amniotic zinc-methionine administration

A 303-bp cDNA of intestinal zinc exporter (ZnT1) was isolated from chicken jejunum by reverse transcriptase-polymerase chain reaction and sequenced, and showed 42% homology to Homo sapiens and Rattus novergicus intestinal ZnT1 genes. This specific probe was used to examine the effect of zinc-methionine (ZnMet) administration on the mRNA expression of ZnT1 and on small intestinal development and functionality. In this study, ZnMet was injected into the naturally consumed amniotic fluid of 17-day-old chicken embryos. The ZnT1 gene showed an approximately 200% increase in its mRNA levels from 48 h post-ZnMet injection, as compared to the control. An analysis of the gene expression of the brush-border enzymes and transporters showed increased mRNA expression of sucrase isomaltase, leucine-aminopeptidase, sodium-glucose cotransporter and Na +K +ATPase transporter (Na +K +ATPase) from 48 h post-ZnMet injection, in comparison to controls. Significant increases ( P<.05) in the biochemical activity of the brush-border enzymes and transporters, and in jejunal villus surface area were detected from day of hatch (96 h post-ZnMet injection) as compared to controls. These results suggest that ZnMet administration into prenatal intestine via injection into the amniotic fluid enhances intestinal development and improves its functionality.

Spontaneous term parturition is associated with decreased amniotic fluid surfactant protein a concentration

Pulmonary surfactant protein (SP)-A has been implicated in the mechanisms responsible for the onset of term parturition (PNAS 2004; 101:4978). The evidence in support of this hypothesis is that: (1) intra-amniotic administration of SP-A to pregnant mice led to the onset of labor; (2) treatment with an anti-SP-A antibody prolonged gestation; and (3) the concentration of SP-A in amniotic fluid increased with advancing gestational age. This study was conducted to determine whether human term parturition is associated with changes in amniotic fluid concentration of SP-A and SP-B.

Intra-amniotic corticosteroids for preterm lung maturation in sheep

Objective The purpose of this study was to compare efficacy on fetal lung maturation of intra-amniotic betamethasone or budesonide with the efficacy of maternal intramuscular betamethasone. Study design Pregnant ewes received intra-amniotic betamethasone (0.5 mg/kg or 2 mg/kg fetal weight), intra-amniotic budesonide (0.5 mg/kg or 2 mg/kg), maternal intramuscular betamethasone (0.5 mg/kg maternal weight), intra-amniotic saline solution, or maternal saline solution. Lambs were delivered 2 or 7 days later, at 124 days of gestation for measurement of respiratory system compliance, ventilatory efficiency index, and surfactant levels. Results Lung function increased 2 days after maternal betamethasone, intra-amniotic betamethasone (2 mg/kg), and intra-amniotic budesonide (2 mg/kg) administration and 7 days after maternal betamethasone or intra-amniotic budesonide (2.0 mg/kg) administration. Lung function was not improved 7 days after intra-amniotic betamethasone (2.0 mg/kg) administration or 2 days after intra-amniotic betamethasone (0.5 mg/kg) or intra-amniotic budesonide (0.5 mg/kg) administration. Intra-amniotic corticosteroid administration increased fetal death and respiratory morbidity. Conclusion Intra-amniotic corticosteroid administration improved preterm lung function, but the associated morbidity and mortality rates suggest that they are not suitable for clinical use.

Betamethasone effects on chorioamnionitis induced by intra-amniotic endotoxin in sheep

Objective Intra-amniotic administration of endotoxin in sheep is a model of subclinical chorioamnionitis. Intrauterine inflammation alters lung development to improve postnatal lung function and may predispose the infant to lung and brain injury. We describe the effects of intra-amniotic endotoxin on cytokines and white cell responses in the membranes and amniotic fluid and investigate the hypothesis that betamethasone treatment suppresses these responses. Study design Pregnant ewes were allocated at random to receive either intra-amniotic saline solution (control animals), maternal intramuscular betamethasone, intra-amniotic endotoxin by ultrasound guidance (10 mg Escherichia coli 055:B5), or a combination of the betamethasone and endotoxin treatments. Lambs were delivered abdominally at 110 to125 days of gestation at time points that ranged from 2 hours to 15 days after treatment. Results When compared with saline solution–injected control animals, the intra-amniotic injection of endotoxin increased white cell counts in amniotic fluid. Levels of interleukin-8, but not interleukin-6, were significantly increased in amniotic fluid from 5 hours to 15 days after intra-amniotic endotoxin injection, and interleukin-8 levels were not decreased by concurrent treatment with betamethasone. After endotoxin treatment, interleukin-1β and interleukin-8 messenger RNA were expressed in chorion, and interleukin-6 messenger RNA expression was localized to chorionic blood vessel epithelium. The half-life of endotoxin in the amniotic fluid was 1.7 days, and levels remained measurable 15 days after injection. Conclusion These findings confirm that the fetus can survive within amniotic fluid that contains endotoxin, white cells, and cytokines for periods of weeks or more. Betamethasone treatment can suppress the initial inflammation in the amnion-chorion, but interleukin-8 levels and inflammatory cells in amniotic fluid were not suppressed 5 and 15 days after betamethasone treatment, presumably because of the slow clearance of bioactive endotoxin from the amniotic fluid.

Cell-cycle alterations underlie cyclophosphamide-induced teratogenesis in the chick embryo.

Cyclophosphamide (CP) embryotoxicity was documented in several studies on different experimental models. We investigate quantitatively the relationship between the embryotoxic effect of CP and the disturbance of the cell-cycle using flow cytometry. Chick embryos on Days 2-4 were treated with 0.5, 1, 2, 4, 8, and 16 microg doses of pure substance of CP by intraamniotic or subgerminal administration routes. Cell-cycle analysis was carried out in the brain, limb buds, hearts, and facial outgrowths dissected from the embryos 6 hr after administration. Samples of nuclear suspensions were obtained by enzymatic and mechanical disintegration of solid tissues in collagenase-dispase, followed by detergent and RNA-ase mediated cytolysis. Nuclei were stained by ethidium bromide. A dose-dependent increase of S-phase cells followed by decrement of G2M cell compartment was observed. The significant block of S-phase cells, however, was not always associated with malformations. The degree of cell-cycle disturbance was expressed more readily by the ratio G2M/S that demonstrated consistently the threshold character of both teratogenic and lethal effects. CP-induced cytotoxicity manifested by dose-dependent disturbance of cell-cycle resulted in an overall depression of proliferation activity clearly associated with the occurrence of malformations and embryonic death. Although a non-significant depression of mitotic activity appeared sufficient to produce malformations on Day 2, remarkably deeper disturbance was needed to interfere with the development of the embryos in more advanced stages. Changes in proliferation rate appear to be a primary and most important event in teratogenesis induced by general toxic agents.

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Effect of adeno-associated virus-specific immunoglobulin G in human amniotic fluid on gene transfer.

Intra-amniotic administration of adeno-associated virus (AAV) vector may be an effective way to deliver gene therapy for treatment of congenital pulmonary and intestinal disorders. In an effort to understand potential barriers to intra-amniotic gene therapy better, we determined whether human amniotic fluid (AF) could act as an inhibitor of AAV2-mediated gene transfer. AF samples were obtained from 21 different human pregnancies during routine amniocentesis at 16-20 weeks of gestation. An immortalized fetal human tracheal epithelial cell line (FHTE) was infected with AAV2 containing a luciferase reporter gene driven by the SV40 promoter in the presence and absence of each AF sample. Inhibition of transgene expression was observed in 8 (38%) of the AF samples (inhibitory AF) and resulted in luciferase levels of only 1.4% +/- 0.6% of those obtained with infection in normal media. Infections in 13 samples (62%) resulted in transgene expression comparable or in excess of infection in media alone (noninhibitory AF). Removal of immunoglobulin G (IgG) from inhibitory AF samples with Protein A returned luciferase expression to control levels (119% +/- 37% of control), suggesting the possible presence of inhibiting antibody. Eleven of the AF samples were evaluated by enzyme-linked immunosorbent assay (ELISA) for specific anti-AAV antibodies. All noninhibitory AF samples were negative (titers of < 1:20; n = 3), and 6 of the 8 inhibitory samples contained specific anti-AAV antibodies at titers ranging from 1:40 to 1:160. These studies demonstrate that AF from some individuals contains AAV-specific IgG that can inhibit gene transfer.

Fetal responses to maternal and intra-amniotic lipopolysaccharide administration in sheep.

A link between intrauterine infection and premature labor is widely accepted, yet the fetal inflammatory responses to such infections are not well understood. Our aim was to use a sheep model in which an inflammatory state was induced by lipopolysaccharide (LPS) administration during pregnancy to the maternal systemic, intra-amniotic or extra-amniotic compartments. Fetal and maternal blood gases and uterine electromyographic activity along with fetal and maternal circulating concentrations of prostaglandins PGE2 and PGFM, cortisol, and interleukin-6 were determined. Maternal systemic LPS treatment resulted in mild maternal hypoxemia, a rise in temperature, greater fetal hypoxemia, and a marked rise in fetal cortisol and PGE2 concentrations that persisted for 48 h. Intra-amniotic administration of LPS at doses higher than those used systemically caused an increase in fetal cortisol and PGE2 concentrations as well as a rise in uterine activity, but these were lesser in magnitude. Extra-amniotic LPS administration caused no overt fetal or maternal inflammatory responses. We conclude that maternal LPS treatment markedly elevated fetal cortisol and PGE2 concentrations. This may be a potential protective mechanism that aids the fetus in the event of premature delivery. The attenuated fetal response to intra-amniotic LPS treatment, despite the much higher dose used, may support a role for the amniotic fluid in protecting the fetus from endotoxin exposure during pregnancy.

A peptide agonist of the neural cell adhesion molecule (NCAM), C3, protects against developmental defects induced by a teratogen pyrimethamine

The neural cell adhesion molecule, NCAM, not only plays an important role in neuronal migration, differentiation and formation of connections in the developing nervous system, but also in the condensation of the mesodermal mesenchyme of the limb bud. Therefore, NCAM may be regarded as a target molecule for preventive strategies aimed at minimizing the effects of teratogens affecting the prenatal development of the nervous system and the skeleton. Treatment of fetuses with the teratogen pyrimethamine results in a reduced body weight, microcephaly and malformations of the hind limbs and forelimbs, e.g. micromelia, brachydactyly and adactyly. We here show that a peptide agonist of NCAM, C3, partly prevented the defects induced by this treatment. Although intra-amniotic administration of C3 at gestational day 14 had no effect on the pyrimethamine-induced reduction in body weight, it rescued the deficit in brain weight (microcephaly), partly reversed a decrease in thickness of the cortical plate, and significantly reduced the number of malformed fetuses. In vitro, C3 promoted survival of PC12-E2 cells treated with pyrimethamine. Since C3 is a peptide mimetic of NCAM, our data strongly suggest that stimulating of NCAM results in neuroprotection in vivo and in vitro.

Fetal responses to intra-amniotic endotoxin in sheep

Our aim was to determine the acute physiologic effects of intra-amniotic endotoxin administration in fetal sheep, and in particular, to determine whether intra-amniotic endotoxin causes an increase in fetal cortisol that could underlie the functional maturation of the fetal lungs previously reported in this model. As in our previous experiments, ewes were randomly assigned to receive a single intra-amniotic injection of either endotoxin (20 mg, Escherichia coli [055:B5], n = 5) or saline (n = 5). Between 0.5 hours before endotoxin and 168 hours after its administration, we measured maternal and fetal arterial pressures and heart rates; fetal and maternal blood samples were collected for measurement of blood gases, electrolytes, glucose and lactate concentrations, white cell counts (total and differential), and plasma cortisol. Fetal arterial carbon dioxide tension and lactate concentration were significantly elevated 6 and 12 hours after endotoxin but returned to pre-endotoxin levels by 24 hours. Fetal plasma cortisol concentrations were significantly elevated at 4 hours and peaked 24 hours after endotoxin, returning to control levels by 2 days. Fetal white cell counts initially decreased (4 hours) and then increased (after 24 hours), becoming significantly elevated 6 days after treatment. Other fetal variables, and all measured maternal variables, were unaffected. Our data suggest that fetal sheep respond to intra-amniotic endotoxin with transient, mild physiologic alterations that follow a time course similar to inflammatory responses reported previously. The elevation in fetal cortisol is insufficient to be the cause of preterm lung maturation shown previously with this treatment.

Indicators of functional differentiation of the chick embryonic kidney

Relevant indicators of the functional capability of the embryonic kidney were tested in the chick mesonephros chosen as an ideal model accessible to direct observation in vivo. Evidence of glomerular filtration (GF) was checked up by the arterial injection of 2% lissamine green (LG) followed by measurement of the LG passage time on days 5, 6 and 7. Presence of the electrogenic transport was investigated by determining the transepithelial potential difference (TPD) which distinguished proximal and distal tubules of the 6-day nephrons. GF and tubular reabsorption could be demonstrated from day 5 by the storage of trypan blue (TB) in proximal tubules after intra-amniotic administration of the dye. The distribution of tubule staining corresponded to the proximal–distal gradient of the nephron differentiation. Activities of embrane enzymes, alkaline phosphatase and 5′-nucleotidase, were detected from day 4. They preceded the ultrastructural maturation in the differentiating proximal tubule epithelia. A semiquantitative evaluation of enzyme activities by the method of measuring of the minimum incubation time (MIT) together with the TB storage, appeared reliable and relevant indicators of the functional properties of mesonephric nephrons, suitable for distinguishing between more and less advanced stages of the nephron development.

Prenatal tracheal ligation or intra-amniotic administration of surfactant or dexamethasone prevents some structural changes in the pulmonary arteries of surgically created diaphragmatic hernia in rabbits.

Characterization of the structural changes occurring in the pulmonary arteries resulting from surgically produced congenital diaphragmatic hernia in rabbits, with particular emphasis on the preventive effects of prenatal tracheal ligation or administration of intra-amniotic dexamethasone or surfactant. Twenty rabbit fetuses underwent surgical creation of a left-sided congenital diaphragmatic hernia on the 24th or 25th gestational day. They were divided according to the following procedures: congenital diaphragmatic hernia (n = 5), congenital diaphragmatic hernia plus tracheal ligation (n = 5), congenital diaphragmatic hernia plus intra-amniotic administration of dexamethasone 0.4 mg (n = 5) or surfactant (Curosurf 40 mg, n = 5). On gestational day 30, all the fetuses were delivered by caesarean section and killed. A control group consisted of five nonoperated fetuses. Histomorphometric analysis of medial thickness, cell nuclei density, and elastic fiber density of pulmonary arterial walls was performed. Arteries with an external diameter > 100 microm have a decreased medial thickness, lower cell nuclei density, and greater elastic fiber density when compared with arteries with external diameter < or = 100 microm. Congenital diaphragmatic hernia promoted a significant decrease in medial thickness and an increase in cell nuclei density in artery walls with external diameter > 100 microm. Prenatal treatments with tracheal ligation or intra-amniotic administration of dexamethasone or surfactant prevented these changes. In arteries with external diameter < or = 100 microm, congenital diaphragmatic hernia promoted a significant increase in medial thickness and in cell nuclei density and a decrease in elastic fiber density. The prenatal treatments with tracheal ligation or intra-amniotic administration of dexamethasone or surfactant prevented these changes, although no effect was observed in elastic fiber density in the congenital diaphragmatic hernia plus dexamethasone group. Congenital diaphragmatic hernia promoted different structural changes for large or small arteries. The prenatal intra-amniotic administration of dexamethasone or surfactant had positive effects on the lung structural changes promoted by congenital diaphragmatic hernia, and these effects were comparable to the changes induced by tracheal ligation.

In utero gene delivery by intraamniotic injection of a retroviral vector producer cell line in a nonhuman primate model.

In utero gene therapy (IUGT) offers the promise of treating a wide variety of genetic diseases before the development of disease manifestations. The most convenient and potentially easiest method of targeting the fetus is through injection into the amniotic cavity. For long-term correction of genetic defects, retroviral vectors have great potential as a tool for gene therapy strategies. However, retroviral vectors are limited by growth to low titers. In an attempt to increase the amount of vector particles delivered and assess the potential of intraamniotic administration, we injected a retroviral vector producer cell line encoding the lacZ gene into the amniotic fluid of a nonhuman primate model. After birth the infants were analyzed for vector-mediated transduction. Two of four fetuses were successfully transduced, with transgene expression detected in the esophagus, trachea, and stomach. In some sections of tissue, nearly 100% of the cells lining the lumen of these tissues were positive for transduction. Although successful, the limited number of tissues in which transduction was observed led to an in vitro analysis of the effects of amniotic fluid (AF). The presence of amniotic fluid inhibited transduction by 99%. AF affected both the transducing activity of the vector and the health of the packaging cells. The negative effects of AF were gestational age dependent; greater inhibition was observed from AF collected at later stages of pregnancy. The fact that transduction was successful despite these negative effects indicates that this approach is a promising strategy for gene therapy.

Fetal monkey surfactants after intra-amniotic or maternal administration of betamethasone and thyroid hormone

OBJECTIVE: To compare direct intra-amniotic injection of betamethasone and thyroxine (T4) with maternal treatment and controls for accelerating pulmonary surfactant production. METHODS: Twelve pregnant monkeys ( Macaca mulatta) on gestational day 125 (term 165 ± 10 days) had surfactant protein A and B concentrations measured in amniotic fluid. In four controls, normal saline was injected into the amniotic fluid; four others (intra-amniotic) received intra-amniotic betamethasone (1 mg) and T4 (60 μg); and in four others (maternal), the dam was given betamethasone (12 mg) intramuscularly, repeated in 24 hours, plus TRH (400 μg) intravenously, repeated every 6 hours for 24 hours. Seventy-two hours after the initial amniocentesis, a hysterotomy was performed and fetal tissue and amniotic fluid harvested for determination of surfactant protein A and B concentrations and immunohistochemical staining for surfactant protein A. RESULTS: Amniotic fluid surfactant protein A was higher with intra-amniotic injection than with maternal treatment ( P < .04) or controls ( P = .07). Amniotic fluid surfactant protein B was higher in the intra-amniotic group than in controls ( P = .06). Immunohistochemical staining for surfactant protein A in the lung tissue was increased in the intra-amniotic group compared with controls (0.145 ± 0.01 versus 0.097 ± 0.001, percent positive staining for surfactant protein A cells per lung tissue cells; P < .03). Birth weight was greater in the intra-amniotic group compared with the maternal group ( P < .03) although not different from the controls. Finally, gut motility and the presence of formed meconium were increased in the intra-amniotic group compared with the other groups ( P < .05). CONCLUSION: Intra-amniotic injection of betamethasone and T4 enhanced lung (and possibly intestinal) maturation of the preterm rhesus fetal monkey compared with maternal injections.

Systematic review of the role of prostaglandins and their synthetase inhibitors with respect to febrile seizures

Prostaglandins are synthesized from arachidonic acid by cyclo-oxygenase enzymes in human and other mammalian brain tissue. Their concentrations in the central nervous system (CSF) are relatively low in normal conditions (Samuelsson, 1964; Wolfe and Mamer, 1975). Elevated prostaglandin levels have been found in animal brains after chemically or electrically induced convulsions (Forstermann et al., 1982). After febrile seizures in children, the concentrations of prostaglandin F2 in CSF are increased and the highest concentrations are measured during the first 3 h after the seizure (Tamai et al., 1983). In children, contrary to adults, unprovoked epileptic seizures do not seem to increase the CSF level of prostaglandin F2 (Tamai et al., 1983). Elevated CSF concentrations of prostaglandin E2 have been found in febrile children without seizures, but possible seizures increase E2 concentrations even more (Loscher and Siemes, 1988). Intra-amniotic administration of prostaglandin F2 may provoke seizures in adults prone to epilepsy (Lyneham et al., 1973). Fever is an essential component of febrile seizures. Thus, it has been logically assumed that antipyretics will prevent febrile seizures, although clinical trials have failed to show their efficacy (Uhari et al., 1995; van Stuijvenberg et al., 1998). Different prostaglandins may have seizure-provoking or inhibiting functions, and drugs inhibiting their synthesis may thus have even deleterious effects on seizure-prone patients. We performed an analysis of the available literature to assess how the different prostaglandins and drugs inhibiting their synthesis affect seizures.

In Utero AAV-Mediated Gene Transfer to Rabbit Pulmonary Epithelium

In utero intra-amniotic administration of adeno-associated virus (AAV) for treatment of cystic fibrosis (CF) has the potential to be an efficient way to target the rapidly dividing undifferentiated cells of the fetal pulmonary epithelium, while simultaneously treating other tissues involved in CF (such as the intestines), but has never before been studied. Intra-amniotic administration of 1x10(12) particles of AAV-luciferase vector to 110 fetal rabbits at 24-25 days gestation resulted in transgene expression in amniotic membranes, trachea, and pulmonary epithelium. The highest level of transgene expression was found in amniotic membranes. Transgene expression peaked in the lungs 10 days after vector delivery, decreased at day 17, and was no longer detectable after 24 days. The number of pulmonary cells transduced was approximately 1 in 500 and immunohistochemical analysis showed expression in varying cell types, including alveolar cells. Transgene expression was not detected in fetal rabbit intestines, skin or liver, nor in maternal ovaries or liver. Intra-amniotic administration of AAV does not result in the tissue inflammation and fetal loss previously documented with in utero adenoviral administration, and results in high levels of transgene expression in amniotic membranes with lower levels in fetal pulmonary epithelium.

Enhanced free radical scavenging and decreased lipid peroxidation in the rat fetal brain after treatment with ethyl docosahexaenoate

In order to explore possible mechanisms to explain previously observed decreases in fetal brain lipid peroxidation (LPO) following intraamniotic administration of ethyl docosahexaenoate (Et-DHA) to near term fetuses, the hydroxyl radical trapping capacity of Et-DHA treated fetal brain preparations was compared to control ethyl oleate injected fetuses by electron spin resonance using 5,5′-dimethyl-1-pyrroline N-oxide (DMPO) probe. Lipid extracts from control brains showed little hydroxyl radical scavenging activity, whereas those from the Et-DHA injected animals exhibited an almost 70% decrease in the amount of DMPO–OH adducts. A marked decrease (58%) in LPO formation was noticed in the Et-DHA treated animals compared to controls. The Et-DHA treatment related trapping capacity resided in the phospholipid fraction of the lipid extract, which was enriched in both docosahexaenoic acid and aminophospholipid contents. The decreased LPO production, as well as increased production of prostaglandin E 2 and nitric oxide by the fetal brain following Et-DHA administration, could be mimicked by a synthetic quinone possessing both hydroxyl radical producing and LPO propagation inhibiting properties. The data are consistent with the possibility that the neuroprotective effect of Et-DHA might be due to possible free radical scavenging ability of the brain tissue and interference with LPO propagation.

Ethyl docosahexaenoate-associated decrease in fetal brain lipid peroxide production is mediated by activation of prostanoid and nitric oxide pathways

Previously we have shown that intraamniotic administration of ethyl docosahexaenoate (Et-DHA) to pregnant rats resulted in decreased lipid peroxidation in the fetal brain, under a variety of conditions (S. Glozman, P. Green, E. Yavin, J. Neurochem. 70 (1998) 2482–2491). In the present study we examine the potential mechanisms to explain this effect. This was done by a pharmacological approach, utilizing brain slice preparations from Et-DHA treated or control rats in the presence of various agents and examining the formation of products in the tissue slices or incubation medium. Et-DHA treated brains produced 2–3-fold more prostanoids (PN) than control brains, indicating cyclooxygenase (COX) activation. Indomethacin at 50 μM inhibited PN formation and also abolished Et-DHA induced decrease in lipid peroxides, as evident by the levels of thiobarbituric acid reactive substances (TBARS) released in the medium. The phospholipase A 2 inhibitors quinacrine and p-bromophenacyl bromide added at 0.1 mM concentration each to either slices from controls or Et-DHA treated fetal brains, decreased TBARS production. Et-DHA treated brains released 2.2-fold more nitric oxide (NO) than control brains and NO synthase (NOS) inhibitors abolished this effect. Increasing the concentration of NO by the addition of an NO donor greatly decreased the concentration of the TBARS in the medium. These results suggest that at least some of the effect of Et-DHA on decreased lipid peroxidation may be explained by a shift of oxygen species utilization via enzymatically regulated, therefore metabolically controlled, COX and NOS activities.

Safety of intra-amniotic digoxin administration before late second-trimester abortion by dilation and evacuation

Objective: The purpose of this study was to determine the safety of intra-amniotic digoxin injection before late second-trimester pregnancy termination by dilation and evacuation through an assessment of maternal systemic digoxin absorption, cardiac rhythm, and coagulation parameters. Study Design: Pregnant women at between 19 and 23 weeks’ gestation received 1.0 mg digoxin through intra-amniotic injection and then had serum digoxin levels determined for 48 hours and Holter cardiac monitoring performed for 24 hours. Clotting parameters were assessed before digoxin injection and 24 hours later, at the time of the dilation and evacuation procedure. Results: Eight patients completed the study. The mean (±SD) serum digoxin peak concentration was 0.81 ± 0.22 μg/L (range, 0.5-1.1 μg/L). The mean (±SD) time to peak digoxin concentration was 11.0 ± 5.55 hours (range, 4-20 hours). Ambulatory cardiac monitoring showed no rhythm or conduction abnormalities associated with digoxin. Prothrombin time, partial thromboplastin time, and fibrinogen levels did not change significantly between determinations before and after the dilation and evacuation procedure (11.5 to 11.4 seconds, 24.1 to 24.4 seconds, and 441 to 475 mg/dL, respectively). Conclusion: The maximum digoxin concentration peak achieved after intra-amniotic injection was in the low therapeutic range. No rhythm or conduction abnormalities associated with digoxin were noted by Holter monitoring. Coagulation parameters did not change significantly. On the basis of the limited systemic absorption and the absence of clinically significant cardiac or clotting effects, intra-amniotically administered digoxin may be considered safe for use before late second-trimester pregnancy terminations. (Am J Obstet Gynecol 2000;182:1063-6.)