Outcome of alloimmunized fetuses managed solely by cordocentesis but not requiring antenatal transfusion.

A published algorithm for the frequency of fetal blood sampling in the management of fetal hemolytic disease allows many pregnancies to continue 1-3 months after the last sample until delivery at term. Though the positive predictive value for antenatal anemia is known, the likelihood of either neonatal hyperbilirubinemia or an unexpected anemia (< 30%) is not. The perinatal records of 51 antigen-positive neonates who did not require treatment antenatally were abstracted.

Affinity cross-flow filtration: purification of IgG with a novel protein a affinity matrix prepared from two-dimensional protein crystals.

In this article, we describe the use of 1- to 2-mum sized affinity microparticles for the isolation and purification of IgG from artificial IgG-human serum albumin mixtures and clarified hybridoma cell culture supernatants by affinity cross-flow filtration. Affinity microparticles were prepared from cell wall fragments of Clostridium thermohydrosulfuricum L111-69, in which the peptidoglycan-containing layer was completely covered with a hexagonally ordered S-layer lattice. After crosslinking the S-layer protein with glutaraldehyde, carboxyl groups from acidic amino acids were activated with carbodiimide and used for immobilization of Protein.

Direct relationship of fetal carboxyhemoglobin with hemolysis in alloimmunized pregnancies.

Because carbon monoxide (CO) is a byproduct of heme degradation and because placental diffusing capacity of CO is limited, we hypothesized that the concentration of CO transported in fetal blood as carboxyhemoglobin (HbCO) would correlate with the severity of fetal hemolytic disease. Fetal blood was obtained by cordocentesis and HbCO was measured by gas chromatography. The two primary study groups included control fetuses (n = 26) and fetuses of Coombs-positive mothers before in utero transfusion (n = 15).

Induction of calcium-dependent nitric oxide synthases by sex hormones.

We have examined the effects of pregnancy and sex hormones on calcium-dependent and calcium-independent nitric oxide synthases (NOSs) in the guinea pig. Pregnancy (near term) caused a > 4-fold increase in the activity of calcium-dependent NOS in the uterine artery and at least a doubling in the heart, kidney, skeletal muscle, esophagus, and cerebellum. The increase in NOS activity in the cerebellum during pregnancy was inhibited by the estrogen-receptor antagonist tamoxifen.

MR of fetal central nervous system abnormalities.

Purpose: To investigate whether MR can provide additional information on fetuses with central nervous system abnormalities as demonstrated by ultrasonography.

Methods: Fetal MR examinations were studied prospectively in 22 pregnant women whose fetuses showed evidence of anomalies on ultrasound performed in the High-Risk Obstetric Clinic.

Results: In 19 of 22 cases, postpartum confirmatory diagnoses were obtained by MR or CT examinations, autopsy, or surgery.

Novel protein a affinity matrix prepared from two-dimensional protein crystals.

In this article, we describe a novel type of affinity matrix which was prepared by covalently binding Protein A to crystalline cell surface layers (S-layers) from the gram-positive Clostridium thermohydrosulfuricum L111-69. S-layers were used in the form of cell wall fragments, which were obtained by breaking whole cells by ultrasonification and removing the cell content and the plasma membrane. In these thimble shaped structures, revealing a size of 1 to 2 mum, the peptidoglycan-containing layer was covered on both faces with a hexagonally ordered S-layer lattice composed of identical glycoprotein subunits.

Fetal echogenic bowel on ultrasound: is there clinical significance?

Though echogenic fetal bowel has been associated with meconium ileus and/or peritonitis, it may be a normal finding in the second trimester. The purpose of this study is to determine which characteristics might distinguish fetuses ultimately having abnormal outcomes in a population at low risk for cystic fibrosis. Seven fetuses with echogenic bowel were identified: 5 fetuses < or = 20 weeks gestation (group 1) and 2 fetuses 20-25 weeks gestation (group 2) at diagnosis.

First trimester three-dimensional ultrasound volumetry of the gestational sac.

First trimester amniotic fluid is an ultrafiltrate of maternal plasma and constitutes the major component of gestational sac volume (GSV). We hypothesized that GSV, assessed by 3-dimensional (3-D) ultrasound volumetry, would reflect function of the early uteroplacental unit and therefore provide a basis for predicting pregnancy outcome. We tested this hypothesis in 38 pregnancies which had first trimester GSV measurements by two investigators thus allowing determination of interobserver variation.

Endothelium-derived relaxing factor inhibits norepinephrine contraction of fetal guinea pig arteries.

As in the adult circulation, the endothelium may play an important role in determining fetal vascular tone. The purpose of this study was to determine the influence of the endothelium on norepinephrine- and phenylephrine-induced contraction of pulmonary and carotid arteries from near-term fetal guinea pigs. Isometric contractions of isolated rings to the cumulative addition of norepinephrine (10(-9)-10(-5) M) were measured before and after 1) endothelium removal, 2) NG-monomethyl-L-arginine (L-NMMA; 10(-4) M) to inhibit endothelium-derived relaxing factor (EDRF), 3) methylene blue (10(-5) M) to inhibit guanylate cyclase, 4) oxyhemoglobin (3 x 10(-6) M) to bind EDRF, and 5) indomethacin (10(-5) M) to inhibit cyclooxygenase.

Effect of intravenous beta-sympathomimetic tocolysis on human fetal serum erythropoietin levels.

Objective: The major stimulus for erythropoietin production is tissue hypoxia. We sought to investigate the relationship of beta-sympathomimetic administration for tocolysis and fetal serum erythropoietin.

Study Design: Umbilical cord blood was obtained from infants whose mothers received intravenous beta-sympathomimetic tocolysis and who were delivered at < or = 34 weeks' gestation.

Umbilical pressure measurement in the evaluation of nonimmune hydrops fetalis.

Objective: Nonimmune hydrops fetalis continues to have a perinatal mortality rate > 50%. Although many abnormalities are associated with nonimmune hydrops fetalis, the direct mechanism by which the hydrops occurs is often obscure, even after delivery. There are at least three possible mechanisms for hydrops: heart failure (whether primary or a secondary effect of obstructed venous return), lymphatic malformation, and liver or peritoneal disease.

"Normal" umbilical arterial and venous acid-base and blood gas values.

Study groups often considered representative of entire populations inevitably do not consider normal fetuses because nonpathologic events can alter the study parameters. Therefore, the term "normal" and its range, when used for comparisons, must be scrutinized by the obstetrician, pediatrician, and those with medicolegal concerns.

Diagnosis of fetal infection in the patient with an ultrasonographically detected abnormality but a negative clinical history.

Unsuspected fetal infection (viral or parasitic) is often overlooked as a possible cause of abnormalities revealed on ultrasonographic examination during pregnancy. Infectious agents can produce a wide spectrum of ultrasonographic findings. Our objective was to highlight those findings and review the rationale and method of antenatal investigation.

Pregnancy reduces serotonin-induced contraction of guinea pig uterine and carotid arteries.

Because platelet activation and serotonin have been implicated in preeclamptic hypertension, we investigated the effect of pregnancy on the contractile response to this agent. Prior studies have shown that the vascular contractions to norepinephrine, angiotensin II, and thromboxane are reduced during normal pregnancy by the altered release of endothelium-derived vasoactive substances. We hypothesized that the contraction to serotonin would also be reduced during pregnancy by an endothelium-dependent mechanism.

Antenatal treatment of fetal alloimmune thrombocytopenia.

Objective: To review our experience with, and to evaluate the efficacy of, antenatal pharmacologic treatment of pregnancies complicated by alloimmune thrombocytopenia.

Methods: We reviewed the records of six pregnancies complicated by alloimmune thrombocytopenia recently cared for at the University of Iowa Fetal Diagnosis and Treatment Unit. All patients had a history consistent with alloimmune thrombocytopenia in a previous gestation.

Human fetal bilirubin levels and fetal hemolytic disease.

The development of secondary fetal anemia in association with maternal red blood cell alloimmunization requires hemolysis. In specimens obtained at the time of a clinically indicated cordocentesis, total and direct umbilical venous bilirubin was measured and the indirect umbilical venous bilirubin calculated in 43 antigen-positive and 30 control fetuses. Twenty-two (51%) of the antigen-positive fetuses had or subsequently developed severe anemia (hematocrit less than 30%).

The effect of fetal age upon normal fetal laboratory values and venous pressure.

Eighty fetuses referred because of maternal alloimmunization or maternal infection underwent umbilical venipuncture and were found to be unaffected. Norms for hematologic, biochemical, and pressure measurements were constructed from 18 weeks until term. Total red blood cell (RBC) count (p less than .

Fetal medicine.

Fetal therapy continues to be an exciting yet controversial field. In utero treatment of a variety of fetal conditions is discussed: parvovirus B19 infection, fetal thyroid dysfunction, fetal ovarian cysts, twin-twin transfusion syndrome, and fetal hemolytic disease. Fetal surgery continues to be controversial.

Endothelium-derived relaxing factor and indomethacin-sensitive contracting factor alter arterial contractile responses to thromboxane during pregnancy.

Objectives: Pregnancy reduces uterine artery contractile responses to norepinephrine and angiotensin II in many species, including the human and the guinea pig, by release of endothelium-derived relaxing substances. We hypothesized that vascular reactivity to thromboxane during pregnancy would also be reduced by a similar mechanism.

Study Design: Isolated ring segments of uterine and carotid arteries from nonpregnant and near-term pregnant guinea pigs were suspended in a myograph for the measurement of isometric tension.

Fetal survival after human parvovirus B19 infection: spectrum of intrauterine response in a twin gestation.

We report the first known symptomatic survivors of congenital parvovirus infection. One fetus was hydropic and the other was growth retarded. There was no evidence of anemia.