Publications by authors named "Horenstein J"

A very large fetal pericardial teratoma was diagnosed at 28 weeks' gestation, prompting urgent multidisciplinary expert consultations to weigh the risks and benefits of various prenatal invasive procedures and preterm delivery for postnatal surgical management. Ultimately, the infant was born by planned cesarean section and underwent immediate cardiopulmonary bypass and surgical resection.

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DNA barcoding is both an important research and science education tool. The technique allows for quick and accurate species identification using only minimal amounts of tissue samples taken from any organism at any developmental phase. DNA barcoding has many practical applications including furthering the study of taxonomy and monitoring biodiversity.

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Selective reduction (SR) via intravascular potassium chloride (KCl) injection is contraindicated in monochorionic twins due to the presence of placental vascular communications, which may serve as a conduit for inter-twin passage of KCl or allow exsanguination of the living twin into the demised twin. After successful selective laser photocoagulation of communicating vessels (SLPCV) for twin-twin transfusion syndrome (TTTS), the twins' circulatory systems are rendered independent. Theoretically, intravascular KCl injection into one twin after successful SLPCV should not result in passage of the feticidal agent nor cause hemodynamic alterations in the co-twin.

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Socioeconomic disadvantage during childhood and adolescence predicts poor mental and physical health and premature death by major medical diseases in adulthood. However, the neural pathways through which socioeconomic factors may exert a developmental influence on health and longevity remain largely unknown. This fMRI study provides novel evidence of a unique relationship between the perception that one's parents had a relatively low social standing--a putative indicator of early socioeconomic disadvantage--and greater amygdala reactivity to threatening facial expressions.

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Low socioeconomic status (SES) increases the risk for developing psychiatric and chronic medical disorders. A stress-related pathway by which low SES may affect mental and physical health is through the perception of holding a low social standing, termed low subjective social status. This proposal implicates overlapping brain regions mediating stress reactivity and socioemotional behaviors as neuroanatomical substrates that could plausibly link subjective social status to health-related outcomes.

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For many general anesthetics, their molecular basis of action involves interactions with GABA(A) receptors. Anesthetics produce concentration-dependent effects on GABA(A) receptors. Low concentrations potentiate submaximal GABA-induced currents.

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The gamma-aminobutyric acid, type A (GABAA), receptor ion channel is lined by the second membrane-spanning (M2) segments from each of five homologous subunits that assemble to form the receptor. Gating presumably involves movement of the M2 segments. We assayed protein mobility near the M2 segment extracellular ends by measuring the ability of engineered cysteines to form disulfide bonds and high affinity Zn(2+)-binding sites.

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Protein movements underlying ligand-gated ion channel activation are poorly understood. Here we used disulfide bond trapping to examine the proximity and mobility of cysteines substituted for aligned GABAA receptor alpha1 and beta1 M2 segment channel-lining residues in resting and activated receptors. With or without GABA, disulfide bonds formed at alpha1N275C/beta1E270C (20') and alpha1S272C/beta1H267C (17'), near the extracellular end, suggesting that this end is more mobile and/or flexible than the rest of the segment.

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Objective: This study was undertaken to evaluate a decade of data on multifetal pregnancy reductions at centers with extensive experiences.

Study Design: A total of 3513 completed cases from 11 centers in 5 countries were analyzed according to year (before 1990, 1991-1994, and 1995-1998), starting and finishing numbers of embryos or fetuses, and outcomes.

Results: With increasing experience there has been a considerable improvement in outcomes, with decreases in rates of both pregnancy loss and prematurity.

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Survival in aerobic conditions is critical to the pathogenicity of many bacteria. To investigate the means of aerotolerance and resistance to oxidative stress in the catalase-negative organism Streptococcus pyogenes, we used a genomics-based approach to identify and inactivate homologues of two peroxidase genes, encoding alkyl hydroperoxidase (ahpC) and glutathione peroxidase (gpoA). Single and double mutants survived as well as the wild type under aerobic conditions.

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Objective: Our purpose was to evaluate the outcomes of selective termination for fetal anomalies at 8 centers with the largest known experiences worldwide.

Study Design: Outcomes in 402 cases of selective termination in pregnancies with dizygotic twins from 8 centers in 4 countries were analyzed by year, gestational age at procedure, and indication. Reductions of fetuses were as follows: 2 to 1, n = 345; 3 to 2, 39; >/=4 to 2 or 3, n = 18.

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Zn2+ inhibits currents through gamma-aminobutyric acid (GABA)A receptors. Its affinity depends on the subunit composition; alpha1beta1 receptors are inhibited with high affinity (IC50 = 0.54 micro M).

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The Saccharomyces cerevisiae adenylyl cyclase complex contains at least two subunits, a 200-kDa catalytic subunit and a 70-kDa cyclase-associated protein, CAP (also called Srv2p). Genetic studies suggested two roles for CAP, one as a positive regulator of cAMP levels in yeast and a second role as a cytoskeletal regulator. We present evidence showing that CAP sequesters monomeric actin (Kd in the range of 0.

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Objective: Our goal was to develop the most comprehensive database possible to counsel patients about selective termination for fetal abnormalities, because no one center has sufficient data to assess much more than crude loss rates.

Study Design: A total of 183 completed cases of selective termination from 9 centers in 4 countries were combined (169 twins, 11 triplets, 3 quadruplets). Variables included indications, methods, (potassium chloride, exsanguination, air embolus), gestational age at procedure, pregnancies lost (< or = 24 weeks), gestational age at delivery, and neonatal outcome.

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The aim of the study was to determine whether color Doppler identifies abnormal fluid within the pericardial space of the fetal were referred for heart. Second- and third-trimester fetuses diagnostic ultrasound. The four-chamber view of the fetal heart was imaged with real-time ultrasonography and examined for the presence or absence of separation of the pericardium from the epicardium, which extended from the atrioventricular junction toward the apex of the ventricle.

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The monocyte monolayer assay (MMA), an in vitro model of in vivo antibody-mediated red blood cell destruction, was previously reported to predict the severity of hemolytic disease of the fetus and newborn accurately when only Rh antibodies and antigen-positive babies were studied. We studied 33 women whose serum contained antibodies with the potential to cause erythroblastosis fetalis; 7 of the 33 women had antibodies other than Rh. None of the babies of the ten women who had consistently negative test results required intrauterine or neonatal transfusions.

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We describe a new technique to evaluate cardiac rhythm using color and pulsed Doppler ultrasonography to identify and record pulmonary arterial and venous waveforms. Fifty fetuses were examined during the second and third trimesters of pregnancy. Simultaneous pulsed Doppler recording of the pulmonary artery and vein was obtained in 100% of fetuses between 15 and 40 weeks' gestation.

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Objective: The four-chamber view of the heart is an important component of the ultrasonographic examination of the fetus. However, during the second trimester of pregnancy the fetal heart cannot always be imaged in every patient. The purpose of this study was to ascertain the rate of successful imaging of the fetal heart during the second trimester and to determine factors that may influence imaging.

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This study was designed to examine ventricular preload by measuring the ductus venosus index during the second trimester of pregnancy. A total of 137 women were entered into the study. Each fetus was examined with real-time, color and pulsed Doppler ultrasound.

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Objective: The purpose of this study was to determine the value of discordant morphometric measurements as identifiers of Down syndrome by evaluating the relationship of biparietal diameter, femur length, biparietal diameter/femur length ratio, and cephalic index between a group of fetuses with trisomy 21 and a control population.

Study Design: Biometric measurements from 48 fetuses with trisomy were reviewed and compared with 107 normal fetuses of similar gestational age. Data were analyzed in 2-week gestational age intervals to determine the effect of gestational age on ultrasonographic detection of Down syndrome.

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Six hundred twenty-nine postterm patients with reliable dates were evaluated for expectant management. Patients with medical or obstetric complications, a Bishop score greater than 6 or abnormal antepartum testing were ineligible for such management. The incidences of macrosomia, fetal distress necessitating cesarean section and low five-minute Apgar scores were similar in patients with labor induction as compared to those managed expectantly.

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One of the shortcomings of antepartum testing in the post-term pregnancy is that it does not identify the majority of fetuses who develop abnormal intrapartum fetal heart rate changes. The purpose of this study was to determine whether antenatal cardiovascular evaluation could aid in the identification of post-term fetuses at risk for intrapartum heart rate abnormalities. Seventy-five patients with a gestational age greater than 41 weeks underwent a non-stress test, amniotic fluid index and real-time assessment of the heart for the presence or absence of a pericardial effusion.

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Daily transvaginal ultrasound (US) scanning of the ovaries to assess follicular development and daily blood sampling were performed on 19 Norplant (Leiras, Turku, Finland) subdermal contraceptive implant users who had regular menstrual cycles and on 10 normally cycling women. Three groups were identified in the implant users based on US finding. Six (31.

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The importance of obtaining cytogenetic studies on antenatally diagnosed structural malformations is well recognized. In two cases, three fetal compartments were sampled, each resulting in successful cytogenetic studies. Fluid was obtained under ultrasound guidance from amniotic fluid, fetal ascites and cystic hygroma fluid.

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