bluuebunny/crossref_metadata_2025_split huggingface dataset:
Outcome of pregnancy in chromosomally normal fetuses with increased nuchal translucency in the first trimester
Authors: Souka A. P. , Krampl E. , Bakalis S. , Heath V. , Nicolaides K. H. 
Published: March 2003

AbstractObjectivesTo study the outcome of chromosomally normal pregnancies with increased nuchal translucency at the 10–14‐week scan.DesignRetrospective study of 1320 chromosomally normal singleton pregnancies with nuchal translucency of ≥ 3.5 mm. In addition to fetal karyotyping these patients were managed with follow‐up scans at 14–16 and 20–22 weeks, specialist fetal echocardiography and in selected cases by infection screening and further genetic testing.ResultsIn the 1320 pregnancies there were 68 (5.15%) spontaneous abortions or intrauterine deaths, 18 (1.36%) neonatal and infant deaths and 154 (11.67%) terminations of pregnancy. In the 1080 (81.82%) survivors, 60 (5.56%) had abnormalities requiring medical or surgical treatment or leading to mental handicap. The chance of a livebirth with no defects in the group with nuchal translucency of 3.5–4.4 mm was 86%, for those with translucency of 4.5–5.4 mm it was 77%, for those with translucency of 5.5–6.4 mm it was 67%, and for those with translucency of ≥ 6.5 mm it was 31%.ConclusionsIncreased fetal nuchal translucency is associated with chromosomal abnormalities, many fetal defects and genetic syndromes. In the majority of cases a series of antenatal investigations, including fetal karyotyping, detailed scans, fetal echocardiography, as well as genetic testing and infection screening, that can be completed by 20 weeks of gestation would distinguish between the pregnancies destined to result in adverse outcome and those leading to the delivery of infants without major defects. Copyright © 2001 International Society of Ultrasound in Obstetrics and Gynecology
Elective cerclage vs. ultrasound‐indicated cerclage in high‐risk pregnancies
Authors: To M. S. , Palaniappan V. , Skentou C. , Gibb D. , Nicolaides K. H. 
Published: March 2003

AbstractObjectiveTo compare pregnancy outcome after elective vs. ultrasound‐indicated cervical cerclage in women at high risk of spontaneous mid‐trimester loss or early preterm birth.MethodsThis was a retrospective study comparing two management strategies in women with singleton pregnancies who had at least one previous spontaneous delivery at 16–33 weeks of gestation. One group was managed by the placement of an elective cerclage at 12–16 weeks and the other group had transvaginal ultrasound examinations of the cervix at 12–15 + 6, 16–19 + 6, and 20–23 + 6 weeks and cervical cerclage was carried out if the cervical length was 25 mm or less.ResultsA total of 90 patients were examined, including 47 that were managed expectantly and 43 treated by elective cerclage. In the expectantly managed group, 59.6% (28/47) required a cervical cerclage. We excluded from further analysis three patients who were lost to follow‐up and three because of fetal death or iatrogenic preterm delivery. Miscarriage or spontaneous delivery before 34 weeks' gestation occurred in 14.6% (6/41) of the elective cerclage group, compared with 20.9% (9/43) in the expectantly managed group (χ2 = 0.219, P = 0.640).ConclusionIn women at increased risk of spontaneous mid‐trimester or early preterm delivery, a policy of sonographic surveillance followed by cervical cerclage in those with a short cervix reduces the need for surgical intervention without significantly increasing adverse pregnancy outcome. Copyright © 2002 ISUOG
Prenatal diagnosis of 22q11 microdeletion in an early second‐trimester fetus with conotruncal anomaly presenting with increased nuchal translucency and bilateral intracardiac echogenic foci
Authors: Machlitt A. , Tennstedt C. , Körner H. , Bommer C. , Chaoui R. 
Published: March 2003

AbstractWe report on a 16‐week fetus, in which detection of increased nuchal translucency thickness and bilateral intracardiac echogenic foci led to the prenatal diagnosis of truncus arteriosus communis, interruption of the aortic arch and aplastic thymus. Cytogenetic examination confirmed a 22q11.2 microdeletion consistent with the suspected CATCH 22 syndrome. Subsequently hydrops fetalis developed and the fetus died in utero at 18 weeks.This case report supports the hypothesis that both cardiac failure and left ventricular outflow tract obstruction may cause increased nuchal translucency thickness. The association between increased nuchal translucency thickness and CATCH 22 syndrome should be considered in diagnostic procedures. The sonographic diagnosis of both increased nuchal translucency thickness and intracardiac echogenic foci requires specialist ultrasonography and echocardiography. In particular, identification of right‐sided or bilateral echogenic foci should prompt further detailed examination. Copyright © 2002 ISUOG
Three‐dimensional sonographic and power Doppler characterization of ovaries in late follicular phase
Authors: Järvelä I. Y. , Sladkevicius P. , Kelly S. , Ojha K. , Nargund G. , Campbell S. 
Published: March 2003

AbstractObjectiveTo determine ovarian blood flow characteristics using three‐dimensional power Doppler ultrasound.MethodsWe examined 30 patients (30 cycles) prior to the start of their in vitro fertilization treatment in the late follicular phase using three‐dimensional power Doppler ultrasound. The volume, vascularization index, flow index, vascularization flow index, mean grayness and the presence of the dominant follicle were determined for each ovary separately.ResultsThe dominant follicle could be detected in 24 out of 30 cycles (80.0%). The volume of the dominant ovary was 9.9 (standard deviation, 4.0) cm3 and the volume of the non‐dominant ovary 6.8 (standard deviation, 2.8) cm3 (P < 0.001). Mean grayness in the dominant ovary was 43.3 (standard deviation, 5.0) and in the non‐dominant 47.2 (standard deviation, 4.0) (P < 0.001), but no other differences could be observed between dominant and non‐dominant ovaries. The shell with a diameter of 2 mm surrounding the dominant follicle had a higher vascularization index (mean, 9.0; standard deviation, 5.9) and vascularization flow index (mean, 4.2; standard deviation, 2.8) than the whole dominant ovary (mean, 5.5; standard deviation, 2.5 and mean, 2.5; standard deviation, 1.3, respectively) (P = 0.003 and 0.002, respectively). In the cycles without a dominant follicle (n = 6), flow index (mean, 50.0; standard deviation, 5.9) and vascularization flow index (mean, 7.3; standard deviation, 6.2) on the left side were higher than on the right side (mean, 40.2; standard deviation, 3.1; mean, 1.5; standard deviation, 1.4; P‐values 0.013 and 0.046, respectively).ConclusionIn the dominant ovary, the volume was higher and mean grayness lower than in the non‐dominant ovary. The vascularization index in the shell surrounding the dominant follicle was higher than the average vascularization index in the whole dominant ovary. In addition, there were differences in the vascularization and flow indices between right and left ovaries, which may be related to the anatomical difference in the venous drainage between right and left ovaries. Copyright © 2002 International Society of Ultrasound in Obstetrics and Gynecology
Measurement precision and normal range of endometrial thickness in a postmenopausal population by transvaginal ultrasound
Authors: Warming L. , Ravn P. , Skouby S. , Christiansen C. 
Published: March 2003

AbstractObjectivesThe aim of this study was to examine the endometrial thickness (ET) in an asymptomatic postmenopausal population, and to assess the long‐term variability.DesignA total of 1182 asymptomatic generally healthy postmenopausal women were enrolled into this cross‐sectional evaluation of the ET. Measurements were performed by transvaginal ultrasound. A subset of the women (n = 178) was examined twice 3 months to 2 years apart to assess the long‐term variability.ResultsCross‐sectionally, ET varied with length of menopause. During the first 5 years after menopause (YSM) the mean ET was 2.3 mm but it decreased by 0.03 mm/year (P < 0.01). From 5 to 13 YSM the ET remained stable at a mean of 1.8 mm with no significant changes (P = 0.13). Thereafter there was a minimal increase of 0.01 mm/year (P < 0.05). In order to minimize the influence of natural changes on ET, only women who had reached the menopause more than 5 years earlier were entered into the subsequent long‐term study. The mean ET was 2.0 mm ± 1.0 mm with no significant differences within or between the observers' measurements. The precision errors were less than 1 mm.ConclusionsThe normal range of the thickness of the postmenopausal endometrium in asymptomatic women varies with YSM. There is a high long‐term agreement within and between observers in measuring the ET. Copyright © 2002 International Society of Ultrasound in Obstetrics and Gynecology
Fetal duodenal obstructions: increased risk of prenatal sudden death
Authors: Brantberg A. , Blaas H‐G. K. , Salvesen K. Å. , Haugen S. E. , Møllerløkken G. , Eik‐Nes S. H. 
Published: March 2003

AbstractObjectivesThe aim of this study was to describe the outcome of fetuses with duodenal obstruction diagnosed prenatally and to compare the outcome with the results of studies of newborns.MethodsAll fetuses with a prenatal diagnosis of duodenal obstruction were registered and evaluated prospectively from January 1985 to December 2000.ResultsDuodenal obstruction was found in 29 fetuses at a mean gestational age of 29+2 weeks. Polyhydramnios was found in 24 cases (83%). Six fetuses (21%) had trisomy 21. Associated anomalies, including trisomy 21, were found in 18 cases (62%). Four fetuses with normal karyotype died in utero at 31–35 gestational weeks. Two of them had associated anomalies, but the anomalies could not explain the prenatal deaths and the deaths occurred suddenly and unexpectedly. Three infants died postnatally; all three had associated anomalies. Four infants with normal karyotype had neurological impairment suggesting that they might have had intrauterine asphyxia.ConclusionsThe present study indicates that duodenal obstruction is a more serious condition than previously believed, with an increased risk of prenatal asphyxia and death, even when the karyotype is normal and no associated anomalies are present. We consider the possibility that it could be caused by bradycardia/asystole following vagal overactivity due to distension of the upper gastrointestinal tract. Copyright © 2002 International Society of Ultrasound in Obstetrics and Gynecology
Conserved developmental processes constrain evolution of lungfish dentitions
Authors: SMITH MOYA MEREDITH , KRUPINA NATASHA I. 
Published: March 2003

abstractAlthough the 3 genera of living lungfish have different‐shaped adult tooth plates, their larval stages have similar patterns of development. The sequence in the pattern of initiation of teeth and their modification through ontogeny in Neoceratodus hatchlings provides a developmental model for fossil hatchling tooth plates (smallest 1–2 mm) recovered as 3‐dimensional dentitions from Andreyevichthys. This Late Devonian lungfish demonstrates that these also have a similar dentition pattern and suggests strongly conserved developmental processes. We postulate that a specific pattern of development, derived within lungfish, has been conserved in extant forms through evolution from the earliest known lungfish. The most basal early dipnoan, Diabolepis speratus, is also known from juveniles with tooth plates formed in this pattern.The lungfish pattern is in marked contrast to the typical linear rows of teeth with lingual replacement for each tooth position, characteristic of most osteichthyan and chondrichthyan dentitions. Uniquely for lungfish, teeth are only added to the lateral ends of the radial rows in the palatal and lingual dentition and are consolidated into dental plates without loss through shedding. It is proposed that this tooth pattern is set up from primordial teeth at the patterning stage of the dentition, one in each dentate region of the larval jaws. Although in post‐Devonian lungfish marginal dentate bones are absent in the adult, in both the fossil and extant hatchling, teeth are present and function on some of the marginal bones. This pattern of development and loss is described and we conclude that in both forms it is also based on a radial pattern of successive tooth initiation. We propose that this ontogenetic pattern constrained the phylogenetic pattern of adult form, through evolution of dipnoan dentitions from 360 MYBP until the present. The universality amongst dipnoans and the implications for such a conserved constraint in the developmental module for the dentition is discussed.
The vertebrate segmentation clock
Authors: POURQUIE OLIVIER 
Published: March 2003

abstractVertebrate somitogenesis has been shown to be associated with a molecular oscillator, the segmentation clock, whose periodicity matches that of the process of somitogenesis. The existence of such a clock in presomitic mesoderm (PSM) cells was originally proposed in theoretical models such as the ‘clock and wavefront’. Molecular evidence for the existence of this clock in vertebrates has been obtained on the basis of the periodic expression of several genes, most of which are related to the Notch signalling pathway. These genes are expressed in a dynamic sequence which appears as a wave sweeping caudo‐rostrally along the whole PSM once during each somite formation. Notch‐pathway mouse and fish mutants lose the dynamic expression of the cycling genes, indicating that Notch signalling is required for their periodic expression, or is required to coordinate the oscillations between PSM cells. Therefore Notch signalling is either part of the mechanism of the oscillator itself or acts as a cofactor required for cycling gene expression. A further potentially important role for the segmentation clock is to periodically activate Notch signalling in the rostral presomitic mesoderm, thereby generating the periodic formation of somite boundaries.
The role of Bapx1 (Nkx3.2) in the development and evolution of the axial skeleton
Authors: LETTICE LAURA , HECKSHER‐SØRENSEN JACOB , HILL ROBERT 
Published: March 2003

abstractThe bagpipe‐related homeobox‐containing genes are members of the NK family. bagpipe (bap) was first identified in Drosophila and there are three different bagpipe‐related genes in vertebrates. Only two of these are found in mammals, the Nkx3.1 and the Bapx1 (Nkx3.2) gene. The targeted mutation in the mouse Bapx1 gene shows a vertebral phenotype in which the ventromedial elements are lacking; these are the centra and the intervertebral discs. In addition, a region of gastric mesenchyme is abnormal. This mesenchyme surrounds the posterior region of the presumptive stomach and duodenum, and in the mutant fails to support normal development of the spleen. In Drosophila, bagpipe has a role in gut mesoderm and the mutant embryos have no midgut musculature. Thus bap related genes in mouse and Drosophila have roles in patterning gut mesoderm; however, neither of the mammalian genes has a discernible role in the gut musculature. In contrast, both mammalian genes have roles in developmental processes that have appeared recently in evolution. The Bapx1 gene found in fish, amphibians, birds and mammals appears to have derived vertebrate specific functions sometime after the split between the jawless fish and gnathostomes.
Comparison of a new pmp22 transgenic mouse line with other mouse models and human patients with CMT1A*
Authors: Robertson A. M. , Perea J. , McGuigan A. , King R. H. M. , Muddle J. R. , Gabreëls‐Festen A. A. , Thomas P. K. , Huxley C. 
Published: March 2003

AbstractCharcot‐Marie‐Tooth disease type 1A is a dominantly inherited demyelinating disorder of the peripheral nervous system. It is most frequently caused by overexpression of peripheral myelin protein 22 (PMP22), but is also caused by point mutations in the PMP22 gene. We describe a new transgenic mouse model (My41) carrying the mouse, rather than the human, pmp22 gene. The My41 strain has a severe phenotype consisting of unstable gait and weakness of the hind limbs that becomes obvious during the first 3 weeks of life. My41 mice have a shortened life span and breed poorly. Pathologically, My41 mice have a demyelinating peripheral neuropathy in which 75% of axons do not have a measurable amount of myelin. We compare the peripheral nerve pathology seen in My41 mice, which carry the mouse pmp22 gene, with previously described transgenic mice over‐expressing the human PMP22 protein and Trembler‐J (TrJ) mice which have a P16L substitution. We also look at the differences between CMT1A duplication patients, patients with the P16L mutation and their appropriate mouse models.
The effect of hyperglycaemia on expression and re‐distribution of VE‐cadherin in human endothelial cells
Authors: Maillard M. , Leach L. 
Published: March 2003

In vitro studies using animal vascular endothelial cells have shown that hyperglycaemia increases monolayer permeability. The mechanism underlying this increase is thought to involve disruption of adherens junctions by phosphorylation of the transmembrane molecule vascular‐endothelium cadherin (VE‐cadherin) and loss of its perijunctional actin anchorage. Recently an alternate mechanism of disruption, i.e. inflammation induced loss of actin independent VE‐cadherin, has been proposed (Lim et al. Microvas. Res. 2001 on IDEAL). The purpose of this study was to expose human endothelial cells to high glucose and follow the fate of VE‐cadherin. Human vein umbilical endothelial cells (HUVEC) were grown to confluence before being exposed to media containing different concentrations of glucose: 5 mm d‐glucose as euglycaemic control, 25 mm d‐glucose as hyperglycaemic medium, and 25 mm l‐glucose as osmotic control. VE‐cadherin localisation was studied using immunocytochemistry and systemic randomised count of junctional profiles which allowed classification of the VE‐cadherin immunoreactivity at cell‐cell borders as continuous or discontinuous. Immunoblot studies and selective protein extraction into Triton‐soluble and Triton‐insoluble fractions were performed in order to measure total protein levels of expression and actin association of VE‐cadherin under the different experimental conditions. Immunoprecipitation studies were used to investigate tyrosine phosphorylation status of VE‐cadherin. Hyperglycaemic exposure of HUVEC for 2 h resulted in a statistically significant (one‐way Anova, P < 0.01) increase in the percentage of discontinuous VE‐cadherin at cell‐cell contacts of HUVEC monolayers, this significance was lost after longer durations (4 d). After 2 h of glucose insult, the total VE‐cadherin expression was not altered, whilst the selective extraction studies showed VE‐cadherin had a greater association with the actin‐cytoskeleton. The tyrosine phosphorylation level of VE‐cadherin was not altered. Our studies reveal that hyperglycaemia does cause redistribution of VE‐cadherin. However the pattern of VE‐cadherin redistribution favours the hypothesis of a loss of VE‐cadherin from actin‐independent membrane microdomains. Furthermore we find this loss is not mediated by the tyrosine kinase signalling pathway.Funded by the European Social Fund.
Endothelial barriers: from hypothetical pores to membrane proteins
Authors: Firth J. A. 
Published: March 2003

The presence of small (4–6 nm diameter) pores in nonbrain capillary walls, permeable to water and small hydrophilic solutes but not most proteins, was established 50 y ago (Pappenheimer et al. Amer. J. Physiol. 167, 1951). This model provides a basis for long recognised features of hydraulic and oncotic pressure driven flows across capillary walls (Starling, J. Physiol. 19, 1896).However the anatomical counterpart of the small pore system proved difficult to establish. Polarised preferences for the caveolar systems or for the paracellular pathway have now matured into a broad agreement that the main small pore pathway in continuous (nonfenestrated) capillaries is likely to be paracellular. The caveolar system is strongly associated with far rarer large pores and with opening‐up by inflammatory agents.Analogy with epithelial paracellular pathways would suggest that tight junctions are likely to be the most restrictive elements. The repeated demonstration by electron microscopy of a gap 4–5 nm wide in the tight junction strands of nonbrain endothelia failed an important test. Such a slit pore occupying the total length of the paracellular cleft would make the total pore area of capillaries in tissues such as muscle about an order of magnitude larger than physiological estimates suggested. Recognition that the tight junctions are interrupted by discontinuities much larger than small pores suggested that the tight junction might function as a shutter limiting the available cleft area rather than as the filter.Subsequent attention has focussed on other regions of the cleft and on the presence of 3 dimensional molecular meshes. Proposed sieve elements range from the glycocalyx to the adhesion molecule complexes of the adherens junctions. The molecular architecture of tight junctions and adherens junctions is moderately well defined in terms of molecular species, and there are differences at both sites between the endothelial and epithelial spectrum of protein expression. However, definition of the size‐restricting pore remains elusive and may require structural biology approaches to the spatial arrangements and interactions of the membrane molecular complexes surrounding the endothelial paracellular clefts.
A quantitative analysis of perineurial cell basement membrane collagen IV, laminin and fibronectin in diabetic and non‐diabetic human sural nerve
Authors: Hill R. E. , Williams P. E. 
Published: March 2003

AbstractThe thickness of the perineurial cell basement membrane was examined in diabetic and non‐diabetic human sural nerve. A significant increase in thickness was found in the diabetic group. The nature of this thickening was investigated using immunohistochemistry and image analysis in order to semi‐quantify three of the major intrinsic components of the perineurial cell basement membrane: collagen IV, laminin and fibronectin. Amounts of all three components were shown to be increased in the diabetic group, but not significantly so. However, significant linear correlations between fascicle size and perineurial collagen IV, laminin and fibronectin were identified in both diabetic and non‐diabetic nerve.