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N Wasserstrum

Publications and source records attributed to N Wasserstrum.

At least 19 recordsLinked to original sources
PubMed1995

Perinatal consequences of maternal hypothyroidism in early pregnancy and inadequate replacement.

UNLABELLED: Maternal hypothyroidism may be associated with a variety of pregnancy complications. OBJECTIVE: We have evaluated the perinatal consequences of maternal hypothyroidism in early and late gestation. DESIGN: Retrospective study of pregnant women, with quasi-experimental design comparing different subjects. SUBJECTS: Forty-three pregnancies in 42 women with hypothyroidism--either biochemically hypothyroid or with a history of hypothyroidism on adequate replacement--and no other preexisting medical conditions. MEASUREMENT: Free thyroxine index (FTI), TSH, and haematocrit at initial antepartum presentation and near term gestation. Pregnancy outcome variables including: rate of Caesarean section performed for fetal distress in labour, neonatal weight percentile, and gestational age at birth. RESULTS: Of 42 hypothyroid pregnancies, six were complicated by fetal distress in labour leading to Caesarean section. Five of these six were severely hypothyroid (defined as FTI < or = 0.6 (normal range 1.1-4.4)) on initial antepartum presentation. In contrast, of the 36 pregnancies without fetal distress, only four initially presented severely hypothyroid (P < 0.001). Conversely, 56% (5/9) of pregnancies which initially presented severely hypothyroid were subsequently complicated by Caesarean section for fetal distress in labour. This compared to 3% (1/33) among those who presented either mildly hypothyroid or euthyroid on replacement (P < 0.0001). Fetal distress correlated with low FTI (P < 0.001) and high TSH at initial presentation. However, it was independent of FTI near term. A relation between fetal distress and TSH near term did not reach statistical significance. Fetal distress also correlated with low maternal haematocrit on admission to labour and delivery (P < 0.05), but was independent of haematocrit and gestational age at initial presentation, neonatal weight percentile, and gestational age at birth. CONCLUSIONS: Severe maternal hypothyroidism early in gestation is strongly associated with fetal distress in labour. This suggests that (1) inadequate maternal replacement leads to fetal distress and (2) maternal thyroid status in early gestation may exert irreversible effects on the fetus, the placenta, and/or on subsequent maternal adaptations to pregnancy. Early adequate replacement therapy is especially prudent in pregnant women presenting with severe hypothyroidism.

Cesarean Section↗
PubMed1994

Inaccurate noninvasive mitral valve area calculation during pregnancy.

OBJECTIVE: To compare two different Doppler echocardiographic techniques for the assessment of the transmitral area in pregnant patients with native mitral valve stenosis or prosthetic mitral valves. METHODS: Eight consecutive gravid women with prosthetic mitral valves or obstructive native mitral valve disease were evaluated using both the pressure half-time and the continuity equation Doppler echocardiographic methods. Heart rate, cardiac output, and transmitral valve gradient and area were calculated. These studies were repeated postpartum in five women. Differences between the two methods were assessed by characterizing the absolute differences between the mean and standard deviation and by paired t tests. Linear regression analysis was also applied. RESULTS: For the five women who also had postpartum studies, antepartum data were similar to those of the full set of eight patients. Postpartum heart rate, cardiac output, and transvalvular gradient were lower than antepartum measurements. Calculations using the continuity equation yielded comparable antepartum and postpartum estimates of transmitral areas (1.31 +/- 0.41 versus 1.32 +/- 0.44 cm2, respectively, r = 0.96). These estimates were also consistent with the initial clinical presentation. In contrast, antepartum transmitral valve areas calculated using the pressure half-time technique (2.67 +/- 0.61 cm2) were markedly higher than postpartum (1.94 +/- 0.58 cm2). The correlation between the estimates of antepartum valve area given by the two methods was not statistically significant (r = 0.02). In contrast, there was excellent postpartum correlation of transmitral area between the methods (r = 0.99), despite a significant difference (P < .001) in the transmitral area calculated with each technique. CONCLUSIONS: The results indicate that Doppler echocardiographic estimates of the transvalvular area using the continuity equation technique during pregnancy are valid. In contrast, estimates of area using the pressure half-time technique in pregnant patients are dubious and could result in life-threatening consequences.

Adult↗
PubMed1993

Contractile effect of endothelin in human placental veins: role of endothelium prostaglandins and thromboxane.

OBJECTIVE: The aim was to study the effects of endothelin-1 on human placental veins and the role of cyclooxygenase products as mediators of these effects. STUDY DESIGN: Rings of placental veins with and without endothelium were suspended in organ chambers filled with physiologic salt solution. After a period of stabilization at optimal basal tension, isometric tensions in the control group were recorded at increasing concentrations of endothelin-1 (10(-10) to 10(-7) mol/L). Rings in the experimental groups were treated with either indomethacin (cyclooxygenase inhibitor, 10(-5) mol/L), dazoxiben (thromboxane synthetase inhibitor, 10(-4) mol/L), or SQ29548 (thromboxane receptor antagonist, 10(-6) mol/L) before addition of endothelin-1. To demonstrate the presence of functional thromboxane receptors in the rings, contractile responses to U-46619 (10(-9) to 10(-6) mol/L), a thromboxane A2 analog were measured. The effectiveness of SQ29548 blockade was tested in rings treated with SQ29548 (10(-6) mol/L) before addition of U-46619. The concentration-response curves of the treated and control groups were compared with the Student paired t test. RESULTS: Endothelin-1 in doses of 10(-10) to 10(-7) mol/L caused concentration-dependent contraction of placental veins. Indomethacin significantly reduced the response of veins with endothelium to low endothelin-1 concentrations (10(-9.5) to 10(-9) mol/L), (p < 0.05). However, it had no effect at higher endothelin-1 concentrations or in vessels without endothelium. The presence of functional thromboxane A2 receptors was confirmed by the vasoconstrictor effect of U-46619 and its blockade by treatment with SQ29548. Neither SQ29548 nor the thromboxane A2 synthesis inhibitor dazoxiben significantly influenced the response to endothelin-1. CONCLUSIONS: These results demonstrated that endothelin-1 is a potent vasoconstrictor in the human placental vein. Although functional thromboxane A2 receptors exist in this vessel, endothelin-1's action is independent of thromboxane A2. Prostaglandins may mediate part of the endothelin-1-induced placental vasoconstriction. However, endothelin-1 acts primarily by a direct effect on vascular smooth muscle cells.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1993

Role of extracellular calcium and calcium channels in the response of human placental venous smooth muscle to endothelin-1.

OBJECTIVE: Our purpose was to evaluate the role of calcium and calcium channels in endothelin-1-induced contraction of the smooth muscle of human placental veins. STUDY DESIGN: Placentas were collected after vaginal delivery at term. After their removal from the chorionic plate, placental veins were divided into rings that were suspended in organ chambers and stretched to optimal tension. In the first part of the study, vessels from six women were initially suspended in calcium-poor modified Krebs-Ringer solution. They were then treated with either EGTA [ethylene glycol-bis(beta-aminoethyl ether)N,N,N',N'-tetraacetic acid; calcium chelator, 0.5 mmol/L] or calcium chloride 2.5 mmol/L (control). Endothelin-1 was then added cumulatively (10(-10) to 10(-7) mol/L), and the resulting changes in isometric tensions were recorded. In the second part of the study vessels from six other women were treated with either (1) normal modified Krebs-Ringers solution (control), (2) calcium-poor modified Krebs-Ringers solution, or (3) nicardipine (dihydropyridine calcium channel inhibitor, 10(-7) mol/L) in separate organ chambers. Endothelin-1 was then added cumulatively. RESULTS: Endothelin-1 produced concentration-dependent contractions in placental veins, with maximal tension reached at 10(-7) mol/L. Substitution of calcium-poor for standard Krebs-Ringers solution in the organ chamber abolished contractions to low endothelin-1 concentrations (< or = 10(-9) mol/L, p < 0.001) but did not affect the contractile response to higher concentrations. EGTA abolished contractions to all concentrations tested (p < 0.02). Nicardipine significantly, but incompletely, inhibited the contractile responses to all endothelin-1 concentrations tested (p < 0.05). CONCLUSIONS: Endothelin-1 induces contraction of the smooth muscle of human placental veins, which requires the influx of extracellular calcium. Dihydropyridine-sensitive calcium channels represent a major route of entry, but other pathways participate. The fetal effects of nifedipine and other calcium-channel blockers deserve specific evaluation in intrauterine growth retardation and other pregnancies complicated by elevated fetal levels of endothelin-1.

Adult↗
PubMed1993

The oxygen consumption/oxygen delivery curve in severe preeclampsia: evidence for a fixed oxygen extraction state.

OBJECTIVE: Increased total body oxygen consumption requirements are usually met by increased oxygen delivery and increased oxygen extraction. In certain conditions (e.g., adult respiratory distress syndrome) the ability to increase oxygen extraction is lost, and any increase in oxygen consumption depends on increased oxygen delivery. The objective of this study was to investigate the oxygen delivery/oxygen consumption relationship in severe preeclampsia. STUDY DESIGN: Thirty-two patients with severe preeclampsia (blood pressure > 160/110 mm Hg; 3 to 4+ proteinuria) were monitored with a pulmonary artery catheter. Baseline oxygen consumption and delivery in a group without volume expansion or pharmacologic vasodilatation were compared with those in a group who had received a magnesium sulfate infusion. RESULTS: Oxygen consumption, oxygen delivery, arterial-venous-oxygen difference, and the oxygen extraction ratio were low when compared to that for normal 32 to 38 week pregnancy. The oxygen extraction ratio, defined as the ratio of oxygen consumption to oxygen delivery, was abnormally low for pregnancy, especially considering the low oxygen delivery levels in these patients. Oxygen consumption was dependent on oxygen delivery over the entire range of values seen. CONCLUSIONS: Severe preeclampsia is associated with an abnormality of tissue oxygen extraction, as evidenced by a low and unresponsive oxygen extraction ratio. Oxygen consumption increases proportionately with increases in oxygen delivery without reaching an oxygen delivery-independent state. Even at high oxygen delivery levels the oxygen consumption in preeclamptic patients is still abnormally low for pregnancy.

Adolescent↗
PubMed1993

Endothelins 1 and 3 and big endothelin-1 contract isolated human placental veins.

Experiments were designed to investigate the reactivity of vascular smooth muscle to endothelins (ETs) in veins taken from human placentas immediately after delivery. The placental veins were cut into rings and suspended between two stirrups in conventional organ chambers (filled with aerated, modified Krebs-Ringer bicarbonate solution) for isometric recording of tension. ET-1 and ET-3 caused concentration-dependent contractions of the isolated human placental veins. The responses induced by ET-1 were greater than those evoked by ET-3 and were not significantly affected by BQ-123, a selective inhibitor of ETA receptors. Contractions to big ET-1 were obtained in rings both with and without endothelium; they were inhibited by phosphoramidon, an inhibitor of endothelin-converting enzyme. These findings indicate that the conversion of the precursor of ET-1 can occur in human placental veins. The receptors mediating the contraction of human placental veins to endothelins do not belong to the ETA subtype; the response to the peptides is probably mediated in part by an uncharacterized ET-receptor subtype and in part by ETB receptors. The output of big ET-1 in the vascular wall or from surrounding tissues in the placenta could be involved in the regulation of venous tone in this organ.

Endothelin Receptor Antagonists↗
PubMed1992

Hereditary factor VII deficiency in pregnancy: peripartum treatment with factor VII concentrate.

This report describes pregnant sisters with severe factor VII deficiency and peripartum management with factor VII concentrate. In this family, two affected members had previously developed severe postpartum hemorrhage when managed with fresh frozen plasma. Therapy-related complications owing to plasma infusion included viral disease transmission and pulmonary edema. Therefore, to lessen the risks of complications, specific factor therapy was initiated shortly before parturition in both patients. Factor VII concentrate was administered prior to delivery and every 6 hr for the next 72 hr to keep trough levels at approximately 10%. Based on peak and trough levels, the mean factor VII half-lives were determined to be 3.6 and 5.7 hr. Use of the concentrate was associated with uncomplicated delivery and minimal postpartum bleeding.

Factor VII↗
PubMed1992

Successful treatment with the Smith-Hodge pessary of cervical incompetence due to defective connective tissue in Ehlers-Danlos syndrome.

Ehlers-Danlos syndrome (EDS) is a heterogeneous group of inherited connective tissue disorders with at least ten distinct types. We report a case of EDS complicated by cervical incompetence. Treatment was undertaken after confirmation that the patient's EDS was not type IV, hence not associated with potentially serious vascular complications. Because of concern about stretching or tearing of the hyperextensible connective tissue associated with EDS, cerclage was not performed. The cervical incompetence due to defective connective tissue was treated with a Smith-Hodge pessary.

Adult↗
PubMed1991

Baroreflex function in normal pregnancy.

The sinoaortic baroreflex is one of the primary mechanisms that regulates blood pressure. Decreased baroreflex sensitivity has been reported in preeclampsia. We sought to determine whether pregnancy altered baroreflex sensitivity. From a radial artery catheter, heart rate and mean arterial pressure were recorded continuously onto a polygraph. The ratio of change in heart rate produced per unit of change in mean arterial pressure was calculated as an index of baroreflex sensitivity. Mean arterial pressure responses to incremental infusions of phenylephrine (0.4 to 2.0 micrograms/kg/min) were measured in the same patients at term (n = 9, 38.0 +/- 0.3 weeks) and again 6 to 8 weeks postpartum (n = 7). The results indicated (1) higher baroreflex sensitivity in pregnancy than in the postpartum period (0.9 vs 0.5 beats/min/mm Hg) (p less than 0.007); (2) attenuated vascular responsiveness to alpha-adrenergic stimulation in pregnancy (p less than 0.05); (3) a relationship between vascular responsiveness and baroreflex sensitivity. We conclude that pregnancy is associated with an increase in baroreflex sensitivity and that the attenuated response to phenylephrine is, at least in part, a result of increased baroreflex sensitivity.

Adolescent↗
PubMed1991

Flow velocity waveforms of the fetal circulation preceding fetal death in a case of lupus anticoagulant.

Flow velocity waveforms of the vascular system were evaluated at 25 weeks 2 days and 27 weeks 5 days of gestation in the case of a severely growth-retarded fetus. At the first scan, the cerebral vessels displayed low pulsatility indexes, reflecting the brain-sparing pattern that characterizes fetal stress. This compensatory reduction was lost at the time of the second, "preterminal" scan.

Adult↗
PubMed1991

Should continuous hydralazine infusions be utilized in severe pregnancy-induced hypertension?

Intravenous hydralazine therapy in severe preeclampsia-eclampsia may be administered by either continuous intravenous infusion or intermittent bolus therapy. We studied the hemodynamic effects of continuous intravenous hydralazine infusion in seven patients with severe pregnancy-induced hypertension. The starting infusion dose was 5 mg/hr and was increased every 15 to 20 minutes by 1 to 2 mg/hr to obtain a 20% reduction in mean arterial blood pressure. The initial mean systolic and diastolic blood pressures were 208.3 +/- 24.8 and 124.3 +/- 11.6 mmHg, respectively. The comparable mean levels following hydralazine therapy was 144 +/- 13.6 and 87 +/- 11.6 mmHg. This decline was obtained at a mean hydralazine dose of 16.04 +/- 3.65 mg/hr. Despite an increase in cardiac output, the rapid uncontrolled decline in blood pressure resulted in five of the seven patients developing fetal distress requiring cesarean delivery. If hydralazine therapy is to be used in severe preeclampsia-eclampsia, we advocate avoidance of continuous intravenous therapy.

Apgar Score↗
PubMed1991

Nitroprusside in preeclampsia. Circulatory distress and paradoxical bradycardia.

In severe preeclampsia, short-term peripartum management of hypertension with hydralazine is complicated by relatively prolonged hypotensive episodes, resulting in fetal distress. We hypothesized that nitroprusside's rapid onset and brief antihypertensive action would permit more controlled blood pressure reduction. Nitroprusside was infused into 10 invasively monitored subjects until mean arterial pressure either 1) was gradually reduced 10-20% or 2) fell abruptly. Subjects fell into two groups, defined by whether the hypotensive effect of nitroprusside was accompanied by a fall in heart rate (group A, n = 8) or a rise (group B, n = 2). Group B showed the expected sinoaortic baroreceptor reflex elevations in heart rate (+17 +/- 6 beats/min) in response to moderate falls in mean arterial pressure (-32 +/- 9 mm Hg) elicited by moderate doses (1.03 +/- 0.23 micrograms/kg/min). However in group A, steep reductions in mean arterial pressure (-75 +/- 22 mm Hg, p less than 0.0001), significantly greater than in group B (p less than 0.05), occurred at much lower doses (0.35 +/- 0.23 micrograms/kg/min; p less than 0.05) and were accompanied by falls in heart rate (-21 +/- 7 beats/min). The apparently paradoxical falls in heart rate and extreme hypotensive responses in group A indicate severe circulatory compromise, corresponding to the cardiac and vasomotor depression that characterizes severe hemorrhage and other forms of acute/severe hypovolemic hypotension. This hemodynamic pattern represents a cardiopulmonary baroreceptor reflex presumably related to the Bezold-Jarisch reflex. The appearance of this pattern in the present study probably reflects the imposition of nitroprusside's prominent venous dilator action on the relatively reduced blood volume that generally characterizes severe preeclampsia.

Adolescent↗
PubMed1990

In utero resolution of hydrops fetalis following the death of one twin in twin-twin transfusion.

A case of massive hydramnios involving a twin-twin transfusion syndrome is presented with death of the larger twin and the development of hydrops fetalis in the surviving smaller twin. The amniotic fluid volume of the surviving twin became normal and the hydrops fetalis resolved spontaneously in utero. Concomitant with the resolution of the hydrops fetalis, the umbilical cord systolic to diastolic ratio improved. At the time of delivery, the hydrops had resolved. The liveborn infant died 11 days later secondary to pulmonary hypertension and cardiorespiratory failure. Although the fetal status improved in utero, the pulmonary hypertension postdelivery resulted in neonatal death.

Adult↗
PubMed1990

Heparin therapy for pregnant women with lupus anticoagulant or anticardiolipin antibodies.

Maternal lupus anticoagulants and anticardiolipin antibodies are associated with a syndrome of recurrent pregnancy loss or preterm birth in live-borns, fetal growth retardation, and placental infarction. Fourteen women with one or more abnormal pregnancy outcomes (total 28 losses, one severely growth-retarded premature live-born) and no normal outcomes were treated with full-dose, subcutaneous, twice-daily heparin therapy in subsequent pregnancies. Treatment was started at an estimated gestational age of 10.3 +/- 4.0 (mean +/- SD) weeks (range 6-18), in a mean total daily dosage of 24,700 +/- 7400 units (range 10,000-36,000). Fourteen of 15 pregnancies resulted in live births at 36.1 +/- 1.7 weeks (range 33-39). The mean birth weight percentile was 57 +/- 21 (range 10-90), and Apgar scores were good to excellent. The number of placental infarcts was fewer in treated cases than in previous deliveries. Five fetuses had third-trimester or perinatal problems with no sequelae, four discovered by close maternal-fetal monitoring. There was an increased rate of preterm and cesarean deliveries. Maternal complications of treatment were few and minor, with no hypertension, preeclampsia, or serious drug-related complications. Heparin appears suitable for further investigation in the treatment of this obstetric syndrome.

Abortion, Spontaneous↗
PubMed1990

Effect of indomethacin on the fetal ductus arteriosus during treatment of symptomatic polyhydramnios.

Ten pregnancies with 13 fetuses complicated by symptomatic polyhydramnios were treated with indomethacin. A baseline fetal echocardiogram was obtained before therapy, repeated 24 hours after the initiation of indomethacin and then performed weekly provided that the ductus arteriosus remained patent. The mean duration of indomethacin therapy was 28.3 +/- 18.9 days. The starting dose in all patients was 25 mg orally every six hours. The ductus arteriosus was noted to constrict in four patients, with the development of tricuspid regurgitation in one. One of the constrictions occurred after 23 days of therapy. In one patient with constriction a reduction of the indomethacin dosage was not associated with constriction, while in the other three, constriction was still evident at a reduced dosage. All constrictions and the tricuspid regurgitation resolved in utero within 24 hours after discontinuation of the indomethacin. We recommend careful monitoring of the fetal ductus arteriosus when treating symptomatic polyhydramnios with indomethacin.

Ductus Arteriosus↗
PubMed1990

Uterine blood flow velocity waveforms in pregnant women during indomethacin therapy.

Continuous-wave Doppler ultrasound was used to assess blood flow velocities and determine the pulsatility index of the uterine arteries in ten pregnant women at 23-33 weeks' gestation during indomethacin therapy for preterm labor or polyhydramnios. There was no statistically significant difference in the pulsatility index of the uterine arteries during maternal indomethacin treatment (mean +/- SD 0.85 +/- 0.29) compared with pre-treatment values (0.85 +/- 0.23). Although studies in animals have reported that indomethacin increases uterine impedance to flow, it appears that it does not affect the uterine impedance in humans.

Blood Flow Velocity↗