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Biomedical subjects

J Lipshitz

Publications and source records attributed to J Lipshitz.

At least 37 records · Page 2Linked to original sources
PubMed1982

Phencyclidine: its transfer across the placenta as well as into breast milk.

Phencyclidine (PCP) is a dangerous and unpredictable drug which is widely abused among young people. Acute placental transfer of this drug was studied in pregnant rabbits and mice where it was shown to cross the placenta readily. Rabbit fetal levels of radioactivity reached their peak 2 hours after parenteral administration of PCP to the doe. In the mouse, where actual PCP levels were determined, there was a tenfold higher concentration of PCP in fetal tissue than in maternal blood. In lactating mice, the drug was found to cross rapidly into breast milk where it reached concentrations which were 10 times that of plasma. As PCP may be teratogenic and has been shown to be harmful to the infant during the postnatal period, those treating pregnant women should be aware to these possible routes of exposure for the developing infant and should counsel their patients accordingly.

Animals↗
PubMed1982

Placental transfer of 14C-hexoprenaline.

The placental transfer of a single intravenous injection of 14C-hexoprenaline was studied in eight pregnant New Zealand white rabbits. Maternal and fetal blood was sampled intermittently for 60 minutes after the injection. An initial rapid decrease in the levels of 14C-hexoprenaline in maternal blood was followed by a second slower phase, whereas fetal levels remained insignificant. The conclusion, therefore, is that the rapid improvement in fetal heart rate after the administration of a single maternal intravenous injection of hexoprenaline in the treatment of fetal distress is due to the action on the uterus and/or on maternal cardiovascular function, and not to direct stimulation of the fetus.

Animals↗
PubMed1982

Meperidine metabolism in the parturient.

A study of meperidine metabolism was undertaken in 21 normal parturients at term. Meperidine, 50 mg intravenously, was the sole analgesic agent used during the intrapartum period. Maternal and cord blood assessment for meperidine and normeperidine was done by gas chromatography-mass spectrophotometry. Most maternal sera showed a typical meperidine elimination curve. A secondary rise in maternal meperidine 30 to 180 minutes after injection was found in 4 patients. One patient showed a significant alteration in normeperidine appearance. These data add further validity to the hypothesis that the pregnant woman can metabolize meperidine by several pathways.

Adolescent↗
PubMed1981

Effects of hexoprenaline on the lecithin/sphingomyelin ratio and pressure-volume relationships in fetal rabbits.

A placebo-controlled, double-blind trial was carried out on 74 New Zealand White rabbit fetuses from 15 does to assess the effect of a fetal injection of hexoprenaline on surfactant release. After the uterus was exposed, half the fetuses received 0.1 ml (0.25 microgram) of hexoprenaline injected intraperitoneally through the intact uterine wall; the other half received an equivalent volume of placebo. After 3 hours, the abdomen was reopened, and the fetuses were surgically delivered and killed before breathing. The lecithin/sphingomyelin (L/S) ratios, obtained from lung washings, revealed a mean of 1.59:1 for the placebo group and 1.92:1 for the hexoprenaline group (p less than 0.001). Pressure/volume curves were generated from the lungs of 24 fetuses from 10 does, and the volume of air in the lungs for each pressure was analyzed in four ways: total volume, volume per gram of fetal body weight, volume per gram of dry lung weight, and as a percentage of total lung capacity at a pressure of 40 cm H2O. A first and second inflation-deflation curve was obtained for each experiment. The lungs from the hexoprenaline-treated group retained significantly more air than those from the placebo group. The most significant comparison was obtained when lung volume was expressed per gram of dry lung weight. The possibility of administering a beta 2-sympathomimetic drug to the mother in advanced preterm labor, specifically to release surfactant in the fetal lung, is suggested.

Amniotic Fluid↗
PubMed1981

Evaluation of Corometrics 315 telemetry system for fetal monitoring.

The Corometrics 315 telemetry system is a commercially available unit which can transmit both fetal heart rate (FHR) and intrauterine or external pressure data to a standard fetal monitor. This system was evaluated in 40 patients, ten of whom were monitored simultaneously by telemetry and direct-wire fetal monitoring. Because of some differences in electronic engineering between the telemetry and direct fetal monitoring systems, the following differences were found: Comparison of the simultaneously obtained FHR recordings revealed that the telemetry system rejected most of the motion artifacts while maintaining true variability. There were no differences as regards readability, FHR, and beat-to-beat variability. The intrauterine pressure values were the same, although the telemetry system gave a smoother waveform with less motion artifact. The main advantages of the telemetry system were found to be: (1) The patient was free to move about and ambulate during labor. (2) It was possible to obtain uninterrupted monitoring while the patient was moved from the labor room to the delivery room and throughout the second stage of labor.

Evaluation Studies as Topic↗
PubMed1981

Effect of maternal dietary restriction on fetal growth and placental transfer of alpha-amino isobutyric acid in rats.

Maternal net weight gain, plasma clearance, and placental and fetal accumulation of I.V. administered 14C-alpha amino isobutyric acid (AIB) on day 20 of gestation were measured in pregnant rats: 1) fed ad libitum throughout gestation (Control), 2) fed 50% of the normal daily food intake during the last week of gestation (catabolic phase), and 3) fed 50% of the normal daily food intake throughout gestation. Dietary restriction during the catabolic phase only resulted in a loss of 54% of the net maternal weight gained during the first two weeks of gestation, while dietary restriction throughout gestation resulted in a net loss of 5.4% of the dams prepregnant weight. Both dietary regimens caused significant growth retardation of the fetus. Maternal plasma clearance of AIB was rapid and occurred at the same rate in all three groups. Placental accumulation and transfer of AIB to the fetus was reduced relative to the controls only in dams fed the restricted diet throughout gestation. Fetal to placental AIB concentration ratios were similar for each group indicting no difference in ability of placentas to release amino acid into the fetal circulation. The results indicate that mechanisms other than reduced nutrient transfer may be responsible for fetal growth retardation induced by maternal malnutrition during the catabolic phase of pregnancy only.

Aminoisobutyric Acids↗
PubMed1981

Diurnal and short-term variation of blood pressure: comparison of preeclamptic, chronic hypertensive, and normotensive patients.

It has been suggested that the decrease in blood pressure during sleep is greater in patients with chronic hypertension than in preeclamptic patients. The DINAMAP (device for indirect noninvasive automatic mean arterial pressure) monitor was used to determine the mean arterial, systolic, and diastolic blood pressure, at 15-minute intervals, and 24 hours. Three groups of 15 patients each were studied: mildly preeclamptic, chronically hypertensive, and normotensive patients in the third trimester. In addition, 2 patients with severe preeclampsia were studied. The automatic readings were compared with auscultated blood pressures. There was short-term variation in the systolic and diastolic blood pressure of 20 to 40 and 15 to 30 mmHg, respectively, with consecutive 15-minute recordings. A decrease in blood pressure during sleep was seen in all groups, except in the 2 patients with severe preeclampsia. This fall varied between 5 and 20 mmHg systolic and 5 and 18 mmHg diastolic. The auscultated blood pressure differed from the automatic blood pressure by 5 to 40 mmHg systolic and 5 to 35 mmHg diastolic. In the clinical management of patients, these findings are significant, as they demonstrate short-term variation in blood pressure and differences in the auscultated versus automatic blood pressure readings. Also, changes in blood pressure occur during sleep; this may be important with regard to the timing and dose of medication given to pregnant patients with chronic hypertension or preeclampsia.

Blood Pressure↗
PubMed1981

Eclampsia. I. Observations from 67 recent cases.

Sixty-seven cases of eclampsia were managed from 1977 to 1980, for an incidence of 1 in 310 deliveries. Eighty-four percent of patients were nulliparous and 82% had received some prenatal care. Prior to convulsion, 14 patients (21%) had a diastolic blood pressure below 90 mmHg, 39% had no edema, and 21% had no proteinuria. Thirty-seven patients (55%) had their first convulsion in the hospital. Eight patients had convulsions while receiving magnesium sulfate therapy. Convulsions occurred post partum in 25 patients (37%). In 11 patients the onset of eclampsia occurrred 3 to 11 days after delivery. The total perinatal mortality was 8.6% for all cases of eclampsia. Excluding postpartum cases, perinatal mortality was 13.3%, but was only 5% for those fetuses alive on admission to the perinatal center. Abruptio placentae was present in 9 cases and accounted for 4 of the 6 perinatal deaths. The high incidence of eclampsia at the authors' center has not decreased over the past 20 years, but maternal mortality has been reduced from 2.1 to 0%. It was disturbing to find that management error played some role in the development of eclampsia in 50% of the cases. Significant errors--including ineffective magnesium sulfate therapy, failure to treat adequately prior to transport, and lack of communication with a perinatal center--are discussed.

Abruptio Placentae↗
PubMed1981

Hexoprenaline pharmacokinetics in pregnant and nonpregnant sheep.

Hexoprenaline, a beta 2-sympathomimetic agent, is used to suppress uterine contractions in the treatment of premature labor. However, little is known regarding the potential of this drug to undergo placental transfer or whether the pregnant state alters any of the pharmacokinetic parameters. Using sheep as a model, intravenous doses of 14C-hexoprenaline were administered to pregnant and non-pregnant animals. Measurable levels of radioactivity did not appear in fetal blood samples. After intravenous bolus administration, blood concentrations in the ewe could be fitted by a triexponential curve characteristic of a three-compartment pharmacokinetic model. Following intravenous infusion, a biexponential curve described the decline in blood concentrations. Mean terminal half lives for total radioactivity ranged from 2.5 to 4.2 hours. The pregnant animals tended to exhibit smaller apparent volumes of distribution and lower values for total body clearance, normalized to body weight, compared to non-pregnant sheep.

Animals↗
PubMed1981

Reassessment of intravenous MgSO4 therapy in preeclampsia-eclampsia.

The occurrence of seizures in preeclamptic and eclamptic women is considered very unlikely during treatment with the standard dose of continuous intravenous magnesium sulfate. During a 21-month period, the authors encountered 13 patients who developed seizure activity while receiving intravenous MgSO4. Serum magnesium (Mg) levels at the time of seizure were below the therapeutic range in 11 of the 13 patients, thus prompting a study of serum Mg levels in preeclamptic patients treated with MgSO4. Random serum Mg samples were obtained from 120 patients treated with intravenous MgSO4 for preeclampsia-eclampsia. The samples were collected 2 to 48 hours after the loading dose and while the patients were taking a maintenance dose of either 1, 2, or 3 g/hr. When a maintenance dose of 1 or 2 g/hr was used, 98 and 50% of the respective serum magnesium values were below levels considered therapeutic by several authors. Therapeutic levels were achieved in ll patients receiving a maintenance dose of 3 g/hr. The recommended maintenance dose of MgSO4 of 1 g/hr was found insufficient to prevent the occurrence of eclamptic seizures in some preeclamptic patients.

Eclampsia↗
PubMed1980

Placental transfer of intravenous fluoride in the pregnant ewe.

Fluoride ion is produced with the biotransformation of two commonly used anesthetics, methoxyflurane and enflurane. Fluoride ion is added to prenatal vitamin preparations and water to prevent carious teeth. Very high levels of fluoride assailure. Previous studies of placental transfer of fluoride ion were conflicting. Our study in pregnant ewes revealed rapid transfer of the fluoride ion across the placenta with high fetal to maternal ratios as early as 1 minute.

Animals↗
PubMed1980

Effect of maternal dietary restriction during pregnancy on maternal weight gain and fetal birth weight in the rat.

The effects of the following dietary regimes on maternal body weight and weights of the products of conception were investigated in the laboratory rat: 50% dietary restriction during the catabolic phase (days 15--21) of gestation; 50% dietary restriction during the anabolic phase (days 1--14) but adequate nutrition during the catabolic phase, and 50% dietary restriction throughout gestation. Total body weight and net maternal weight at term were significantly reduced in all three test groups. Restricting dietary intake during the anabolic phase resulted in decreased maternal weight gain. Feeding an adequate diet during the catabolic phase, following restriction during the anabolic phase, caused only a slight decrease in net maternal weight, while term fetal weight approximated that of controls. Dietary restriction during the catabolic phase, or throughout gestation, caused increased net maternal weight loss. Term fetal weight in both groups was significantly lower than that of the controls, but not different from each other. The results indicate that the dam is able to mobilize nutrients stored during the anabolic phase of pregnancy. Mobilization of these nutrients did not significantly increase fetal growth, however, supporting the hypothesis that the dam is able to compartmentalize available nutrients during malnutrition and prevent serious depletion of these stores by the fetus.

Animals↗
PubMed1980

The late postpartum eclampsia controversy.

The diagnosis of late postpartum eclampsia remains controversial. Six cases thought to represent eclampsia occurring 3 or more days post partum are reported, as is a review of the pertinent literature.

Adolescent↗
PubMed1980

Sinusoidal fetal heart rate pattern.

The etiology of sinusoidal fetal heart rate (FHR) patterns is diverse and consequently they ave been associated with poor as well as normal fetal outcome. Four patients who demonstrated sinusoidal FHR patterns are reported, and the factors associated with these patterns and their effect on fetal outcome are discussed. Three of the babies were delivered by emergency cesarean section and were markedly depressed at birth. Two of the infants died and the third required prolong hospitalization. The fourth baby was delivered vaginally and had a normal outcome. The possible pathophysiology is discussed and recommendations are made for the management of this FHR pattern.

Acidosis↗
PubMed1980

Placental transfer and other physiologic studies with intravenous butorphanol in the anesthetized pregnant ewe.

In clinical evaluation, butorphanol has been used in labor pain with analgesia and newborn outcome comparable to meperidine. Only limited placental transfer studies have been done in the human. The placental transfer and effect of intravenous butorphanol (2 mg) on avrious cardiovascular parameters were determined in anesthetized sheep. Serum butorphanol was determined by a specific radioimmunoassay. Butorphanol 2 mg intravenously did not affect the measured cardiovascular parameters in either ewe or fetus. Butorphanol could be demonstrated in the fetal circulation within one minute of administration and appeared to reach equilibrium in the maternal circulation rapidly and to remain in equilibrium thereafter. A biexponential decline of butorphanol was observed in the maternal serum with a terminal elimination half-life of 50 minutes. The data suggest butorphanol distribution in the pregment ewe can be conceptualized by the two compartment model, with the fetus as part of the peripheral compartment. These studies support the clinical finding from other studies that butorphanol appears to be a safe analgesic for use in labor pain.

Anesthesia↗