bluuebunny/crossref_metadata_2025_split huggingface dataset:
First‐trimester trisomy screening: nuchal translucency measurement training and quality assurance to correct and unify technique
Authors: Snijders R. J. M. , Thom E. A. , Zachary J. M. , Platt L. D. , Greene N. , Jackson L. G. , Sabbagha R. E. , Filkins K. , Silver R. K. , Hogge W. A. , Ginsberg N. A. , Beverly S. , Morgan P. , Blum K. , Chilis P. , Hill L. M. , Hecker J. , Wapner R. J. 
Published: March 2003

AbstractObjectiveTo describe the process of training for measuring nuchal translucency at five clinical centers in North America and to evaluate methods of quality assurance and feedbackDesignThroughout a period of 18 months, the performance of sonographers in measuring fetal nuchal translucency was monitored using qualitative and quantitative methods of review. After 12 months, different approaches (written and personal feedback) were used to inform sonographers of technical aspects that needed to or could be improved.ResultsOn initial qualitative review, discrepancies in judgment from different reviewers coincided with suboptimal magnification, failure to visualize the amniotic membrane and/or use of cross‐shaped calipers. At subsequent global review, 13 (29%) images of nuchal translucency measurements were considered unacceptable. Quantitative assessment revealed that, during the first part of the study, the means from four sonographers were significantly smaller and the mean from the fifth sonographer was significantly larger than expected on the basis of findings from The Fetal Medicine Foundation (P < 0.0001). Following feedback, sonographers who underestimated nuchal translucency and who received a written report only did not change measurements overall (P = 0.9759). In contrast, those who received additional intervention showed a marked difference (P < 0.0001).ConclusionsGlobal qualitative review of images from one sonographer may be preferable to assessment of individual aspects of images. Results from global qualitative review correspond well with findings from quantitative analysis, indicating that the latter can be applied for ongoing audit. Observation of divergent results should prompt extensive personal feedback, rather than a written report, to prevent sonographers from settling in their own, inappropriate technique. Copyright © 2002 ISUOG
Undescended testicle and a meconium‐filled hemiscrotum: prenatal ultrasound appearance
Authors: Gililland A. , Carlan S. J. , Greenbaum L. D. , Levy M. C. , Rich M. A. 
Published: March 2003

AbstractWe report a case of a meconium‐filled hemiscrotum detected by prenatal ultrasound and misdiagnosed as in‐utero testicular torsion. Over the 2 months that the mass was followed, the ultrasound characteristics and size changed significantly. Imaging immediately after birth and early surgical treatment resulted in a favorable outcome. Copyright © 2000 International Society of Ultrasound in Obstetrics and Gynecology
Assessment of uterine artery blood flow in normal first‐trimester pregnancies and in those complicated by uterine bleeding
Authors: Pellizzari P. , Pozzan C. , Marchiori S. , Zen T. , Gangemi M. 
Published: March 2003

AbstractObjectiveTo compare uterine artery blood flow in normal first‐trimester pregnancies with those complicated by uterine bleeding.MethodsUterine artery blood flow was investigated by transvaginal color Doppler in 46 pregnant women affected by uterine bleeding and in a control group of 35 women with normal intrauterine pregnancy. Gestational age ranged from the 6th to the 12th week. Three blood flow values were calculated, the pulsatility index, the resistance index and the peak systolic velocity. Results were compared between the two groups.ResultsOf the 46 patients affected by uterine bleeding, 18 had an incomplete miscarriage, eight had a blighted ovum, five had a missed miscarriage and 15 continued their pregnancy until term and delivered liveborn infants. No significant differences were found in any of the three vascular indices between the normal and the pathological groups of patients. Uterine artery pulsatility and resistance indices decreased with gestational age in both normal and abnormal pregnancies but this change was not statistically significant. The peak systolic velocity significantly increased with gestational age in the control group but not in the pathological group. In patients with a retroplacental hematoma, uterine vascular resistance appeared higher than in those without a hematoma, while the peak systolic velocity showed no difference between the two groups.ConclusionDoppler analysis of the uterine artery blood flow is unlikely to have a clinical role in the management of early pregnancies complicated by uterine bleeding. Copyright © 2002 ISUOG
Serial translabial sonographic measurement of cervical dimensions between 24 and 34 weeks' gestation in pregnant Thai women
Authors: Liabsuetrakul T. , Suntharasaj T. , Suwanrath C. , Leetanaporn R. , Rattanaprueksachart R. , Tuntiseranee P. 
Published: March 2003

AbstractObjectiveTo assess serial changes of cervical dimensions in pregnant Thai women between 24 and 34 weeks' gestation by translabial sonography.MethodsA longitudinal study of cervical dimensions obtained by translabial sonography at 24, 28, 30, 32, and 34 weeks' gestation in 144 women was conducted. The gestational age at labor was recorded and women were defined as having preterm labor or term labor according to whether there was onset of true labor pain before or after 37 completed weeks, respectively. Cervical changes over time were analyzed by repeated anova. The associations between cervical dimensions and gestational age, parity and prepregnancy body mass index were calculated by multiple linear regression analysis.ResultsCervical length decreased whereas cervical width increased as gestational age advanced. Cervical length and width in women with term labor, but only cervical length in women with preterm labor, changed significantly throughout the period of 24–34 weeks' gestation (P < 0.01). The cervix was significantly longer in parous women and in women with a body mass index of more than 26 kg/m2, but was shorter in women of advanced gestational age. The cervix was significantly wider in parous women and in those of advanced gestational age. Weekly crude rate, adjusted for parity and prepregnancy body mass index, of both cervical length shortening and cervical width widening was 0.4 mm in women with term labor. Women with preterm labor had cervical shortening of 0.5 mm per week.ConclusionsGestational age, parity and prepregnancy body mass index are significantly associated with the dynamic changes of cervical length and width in Thai women. These factors should be considered when assessing normal values of cervical dimensions and for predicting the risk of preterm delivery.
Gestational sac diameter in very early pregnancy as a predictor of fetal outcome
Authors: Oh J. S. , Wright G. , Coulam C. B. 
Published: March 2003

AbstractObjectiveTo determine whether transvaginal sonographic measurement of gestational sac diameter in pregnancies 28–42 days from the last menstrual period can predict whether a pregnancy results in a normal term birth or a spontaneous miscarriage.DesignGestational sac diameter was measured during the 4th and 5th weeks of gestation from the last menstrual period in 67 women who had a total of 102 ultrasound scans. These pregnancies were followed until one of two outcomes occurred: term gestation (n = 32) or spontaneous miscarriage (n = 35). Gestational sac diameter as a function of gestational age was compared in each of the groups.ResultsThe mean diameter of the gestational sac at 28–35 days from the last menstrual period among normal pregnancies did not differ significantly from that in those that subsequently miscarried (2.6 mm vs. 2.7 mm; P = 1.00). In pregnancies 36–42 days from the last menstrual period, the mean sac diameter was significantly different between the two groups (normal group, mean sac diameter, 8.2 mm and miscarriage group, mean sac diameter, 4.5 mm; P < 0.001).ConclusionThere is no difference in gestational sac diameter at 28–35 days from the last menstrual period in normal and abnormal pregnancies. However, smaller than expected sac diameter in pregnancies 36–42 days from the last menstrual period is predictive of spontaneous miscarriage. Copyright © 2002 International Society of Ultrasound in Obstetrics and Gynecology
Evaluation of the fetal coronary circulation
Authors: Baschat A. A. , Gembruch U. 
Published: March 2003

AbstractPrenatal ultrasound today allows the detailed study of small caliber vascular beds including the fetal coronary arteries and the coronary sinus. The coronary circulation is unique because of its critical role in myocardial metabolism and function and its ability to adapt in many fetal conditions. The ultrasound examination techniques for the evaluation of the fetal coronary circulation are presented. Evaluation of the coronary arteries is primarily achieved by color flow imaging and pulsed wave Doppler. Conditions such as fetal growth restriction, anemia, ductus arteriosus constriction and bradycardia are associated with evidence of enhanced coronary blood flow. These findings suggest that short‐term autoregulation and long‐term alterations in myocardial flow reserve are present in the human fetus. At present, examination of coronary sinus blood flow has limited clinical utility, while increases of the coronary sinus diameter or attenuation of coronary sinus dynamics may provide useful markers of abnormalities of central venous drainage. Abnormal vascular connections between the coronary arteries and the ventricular cavities may be observed in outflow tract obstructive cardiac lesions. In these conditions prenatal detection of coronary fistulae may have a potential impact on outcome and therefore counseling and perinatal management. Copyright © 2002 International Society of Ultrasound in Obstetrics and Gynecology
Ultrasound estimation of amniotic fluid volume using the largest vertical pocket containing umbilical cord: measure to or through the cord?
Authors: Magann E. F. , Chauhan S. P. , Washington W. , Whitworth N. S. , Martin J. N. , Morrison J. C. 
Published: March 2003

AbstractObjectivesThe purpose of this investigation was to determine the preferable method, either measuring to the umbilical cord or through the umbilical cord to the base of the pocket, of ultrasonically estimating amniotic fluid volume.Subject and methodsThis was a prospective study carried out in singleton pregnancies undergoing a third‐trimester amniocentesis. The amniotic fluid index (AFI) and single deepest pocket (SDP) were measured prior to amniocentesis. If measured spaces contained umbilical cord, measurements were made to and through the cord. Actual amniotic fluid volume was determined by the dye‐dilution technique.ResultsOne‐hundred pregnancies were evaluated. Low dye‐determined volume was identified in a significantly greater number of pregnancies using the AFI to the cord (7/28, 25%) compared to through the cord (2/28, 7%) (P = 0.025). The SDP technique to the cord was superior in low volumes (2/28, 7%) vs. (0/28, 0%) through the cord (although statistical significance could not be determined because there were no low through‐the‐cord measurements).ConclusionsFor the detection of low amniotic fluid volumes, the AFI to the cord is better than through the cord. Measurement to the cord and through the cord had similar accuracy for both the AFI and SDP techniques in normal and high dye‐determined amniotic fluid volumes. Copyright © 2002 International Society of Ultrasound in Obstetrics and Gynecology
Transvaginal ultrasonography in predicting placenta previa at delivery: a longitudinal study
Authors: Mustafá S. A. , Brizot M. L. , Carvalho M. H. B. , Watanabe L. , Kahhale S. , Zugaib M. 
Published: March 2003

AbstractObjectivesTo determine the extent of overlapping of the internal cervical os by the lower placental edge at 11–14 weeks' gestation which best predicts placenta previa at term.Patients and methodsThis was a prospective study initially involving 381 singleton pregnancies with a live fetus at 11–14 weeks attending for routine antenatal care. The distance between the lower placental edge and the internal cervical os was longitudinally evaluated by transvaginal ultrasound examination at 11–14 weeks', 20–24 weeks', and 30–34 weeks' gestation. The first 203 cases were selected at random (first phase) and after this period only cases with the lower placental edge reaching and/or overlapping the internal cervical os were followed up (n = 170, second phase). Thus a total of 373 cases were analyzed, 351 of whom were examined in all three trimesters. Multiple regression analysis was used to estimate the probability of predicting placenta previa at term using the overlap of the lower placental edge over the internal cervical os in the first trimester of pregnancy.ResultsA change in the relative position of the placenta (placental migration) was observed in all 351 cases examined in the three trimesters of pregnancy. In the general population, represented by the 203 cases (first phase), the incidence of placenta previa at 11–14 weeks' gestation was 42.3% (86/203), at 20–24 weeks' 3.9% (8/203) and at term 1.9% (4/203). A total of 18 cases of placenta previa and 17 cases of marginal placenta were observed at term. It was estimated that when the lower placental edge overlaps the internal cervical os by 23 mm at 11–14 weeks the probability of placenta previa at term is 8% with a sensitivity of 83.3% and specificity of 86.1%.ConclusionThe present study establishes the probability of placenta previa at term depending on the relationship of the lower placental edge to the internal cervical os at 11–14 weeks. Copyright © 2002 International Society of Ultrasound in Obstetrics and Gynecology
Otx genes in evolution: are they involved in instructing the vertebrate brain morphology?
Authors: ACAMPORA DARIO , BOYL PIETRO PILO , MARTINEZ‐BARBERA JUAN PEDRO , ANNINO ALESSANDRO , SIGNORE MASSIMO , SIMEONE ANTONIO 
Published: March 2003

abstractPrevious mouse models have indicated that Otx1 and Otx2 play an important role in brain and sense organ development and, together with the Drosophila orthodenticle (otd) gene, they share a high degree of reciprocal functional equivalence. Interestingly, mouse models replacing the same region of the Otx2 locus with Otx1, otd or lacZ genes have revealed the existence of a differential post‐transcriptional control between the visceral endoderm (VE) and epiblast cells. Indeed Otx1, otd or lacZ mRNA were transcribed in both tissues but translated only in the VE. Embryos lacking OTX1 or OTD proteins in the epiblast and derived tissues, such as the neuroectoderm and axial mesendoderm (AME), fail to maintain the anterior identity and result in a headless phenotype. This finding leads us to hypothesise that, during evolution, the specification of the vertebrate‐type brain may have required epiblast cells to translate Otx2 mRNA in order to establish maintenance properties. The establishment of this regulatory control might have been reflected into a remarkable reorganisation of the rostral CNS architecture and might have represented an important event in the evolution of the vertebrate head. Current data suggest that the Otx2 replaced region and in particular the 3′ untranslated region (UTR), may contain regulatory element(s) necessary to translate and/or stabilise Otx2 mRNA in epiblast and its derivatives.
The incidence of the lateral bridge of the atlas vertebra
Authors: MITCHELL JEANETTE 
Published: March 2003

The vertebral artery, in its course from the subclavian artery to the basilar artery, is vulnerable to damage or distortion from external factors such as bony, ligamentous or muscular structures (Mehalic & Farhat, 1974; Parkin et al. 1978; Schellhas et al. 1980; Braun et al. 1983; Dunne et al. 1987; Fast et al. 1987). In the atlas vertebra, the retroarticular canal and the lateral bridge are examples of bony outgrowth or exostosis which may cause external pressure on the vertebral artery as it passes from the foramen transversarium of the vertebra to the foramen magnum of the skull. If this pressure is severe enough, as may occur during the extreme rotatory movements carried out during therapeutic manipulation of the cervical spine, the vertebral artery may be compressed (Lamberty & Zivanovich, 1973), reducing its cross‐sectional area, and compromising its blood flow (Taitz & Nathan, 1986). Vertebrobasilar ischaemia from compression of the vertebral arteries by osteophytes is an uncommon occurrence under normal circumstances (Warlow, 1996).There are few studies of the lateral bridge of the atlas reported in the literature (MacAlister, 1869, 1893; Lamberty & Zivanovic, 1973; Saunders & Popovich, 1978; Taitz & Nathan, 1986). The lateral bridge was first described by MacAlister (1869, 1893) as a variety of the ‘posterior glenoid process’ (the retroarticular canal), which he termed the ‘gleno‐transverse bony arch’. As its name implies, it is a lateral outgrowth of bone from the superior articular facet or lateral mass to the posterior root of the transverse process of the atlas (MacAlister, 1869, 1893; Lamberty & Zivanovic, 1973; Saunders & Popovich, 1978; Taitz & Nathan, 1986). The retroarticular canal is formed by an exostosis passing from the posterior surface of the lateral mass to the posterior margin of the vertebral artery groove of the atlas. Thus the lateral bridge forms another arch, secondary to the retroarticular canal, through which the vertebral artery must pass (MacAlister, 1869).
Insect oenocytes: a model system for studying cell‐fate specification by Hox genes
Authors: GOULD ALEX P. , ELSTOB PHILIP R. , BRODU VÉRONIQUE 
Published: March 2003

abstractDuring insect development, morphological differences between segments are controlled by the Hox gene family of transcription factors. Recent evidence also suggests that variation in the regulatory elements of these genes and their downstream targets underlies the evolution of several segment‐specific morphological traits. This review introduces a new model system, the larval oenocyte, for studying the evolution of fate specification by Hox genes at single‐cell resolution. Oenocytes are found in a wide range of insects, including species using both the short and the long germ modes of development. Recent progress in our understanding of the genetics and cell biology of oenocyte development in the fruitfly Drosophila melanogaster is discussed. In the D. melanogaster embryo, the formation of this cell type is restricted to the first 7 abdominal segments and is under Hox gene control. Oenocytes delaminate from the dorsal ectoderm of A1‐A7 in response to an induction that involves the epidermal growth factor receptor (EGFR) signalling pathway. Although the receptor itself is required in the presumptive oenocytes, its ligand Spitz (Spi) is secreted by a neighbouring chordotonal organ precursor (COP). Thus, in dorsal regions, local signalling from this component of the developing peripheral nervous sytem induces the formation of oenocytes. In contrast, in lateral regions of the ectoderm, Spi signal from a different COP induces the formation of secondary COPs in a homeogenetic manner. This dorsoventral difference in the fate induced by Spi ligand is controlled by a prepattern in the responding ectoderm that requires the Spalt (Sal) transcription factor. Sal protein is expressed in the dorsal but not lateral ectoderm and acts as a competence modifier to bias the response to Spi ligand in favour of the oenocyte fate. We discuss a recently proposed model that integrates the roles of Sal and the EGFR pathway in oenocyte/chordotonal organ induction. This model should provide a useful starting point for future comparative studies of these ectodermal derivatives in other insects.
Myoarchitecture and vasculature of the heart ventricle in some freshwater teleosts
Authors: Simões K. , Vicentini C. A. , Orsi A. M. , Cruz C. 
Published: March 2003

AbstractThe morphological characteristics of the ventricular myocardium and of coronary vascularization were studied in three freshwater teleost species, Piaractus mesopotamicus, Colossoma macropomum and Clarias gariepinus (African catfish), by correlating their ventricular shapes and swimming habits. In Piaractus mesopotamicus and Colossoma macropomum, species with highly active swimming habits, the cardiac ventricle showed a pyramidal shape and a richly vascularized myocardium consisting of an outer compact layer and inner spongy layer. In Clarias gariepinus, a less active species, we observed a saccular ventricle with a mixed myocardium and coronary arteries, in contrast to the ventricular structure of other species described in the literature.
Human ES cells – haematopoiesis and transplantation strategies*
Authors: Kaufman D. S. , Thomson J. A. 
Published: March 2003

AbstractHuman embryonic stem (ES) cells provide a novel opportunity to study early developmental events in a human system. We have used human ES cell lines, including clonally derived lines, to evaluate haematopoiesis. Co‐culture of the human ES cells with irradiated bone marrow stromal cell lines in the presence of fetal bovine serum (FBS), but without other exogenous cytokines, leads to differentiation of the human ES cells within a matter of days. A portion of these differentiated cells express CD34, the best‐defined marker for early haematopoietic cells. Haematopoietic colony‐forming cells (CFCs) are demonstrated by methylcellulose assay. Myeloid, erythroid, megakaryocyte and multipotential CFCs can all be derived under these conditions. Enrichment of CD34+ cells derived from the human ES cells markedly increases the yield of CFCs, as would be expected for cells derived from adult bone marrow or umbilical cord blood. Transcription factors are also expressed in a manner consistent with haematopoietic differentiation. This system now presents the potential to evaluate specific conditions needed to induce or support events in early human blood development. Human ES cells are also a novel source of cells for transplantation therapies. The immunogenicity of ES cell‐derived cells is unknown. The unique properties of ES cells afford the opportunity to explore novel mechanisms to prevent immune‐mediated rejection. Potential strategies to overcome rejection will be presented, including creation of haematopoietic chimerism as a means to successfully transplant cells and tissues derived from human ES cells.