In vitro simulation of placental transport: part II. Glucose transfer across the placental barrier model.

INTRODUCTION: In utero fetal development and fetal programming for adulthood life are strongly associated with maternal-to-fetal transfer of nutrient and other substances. Gestational diabetes mellitus (GDM) is a major problem and associated with abnormal fetal development, but the mechanisms underlying glucose transport across the placenta barrier (PB) are not completely understood. METHODS: We developed a placenta simulator that can mimic feto-maternal blood circulations along with real transfer across the in vitro biological model of the PB, which is made of a co-culture of endothelial cells (EC) and trophoblast cells (TC) on both sides of a denuded amniotic membrane (AM). Maternal-to-fetal transfer of glucose was monitored over 24 h. RESULTS: The AM is highly permeable to glucose compared to the cellular structures and can serve as a substrate for the co-culture model. The transfer characteristics for glucose are independent of its initial concentration in the maternal compartment, but strongly dependent on the cellular components of the PB. The EC are more resistive to glucose transfer than the TC. The in vitro PB model is the most resistive to glucose transfer. DISCUSSION AND CONCLUSION: The good correlation between the present in vitro results with existing in vivo data demonstrated the potential of this new approach, which can be extended to study various aspects of transplacental transfer, including medications, relevant to GDM or any problem related to in utero programing.

In vitro simulation of placental transport: part I. Biological model of the placental barrier.

INTRODUCTION: The placental barrier (PB) is the thin biological membrane made of endothelial cells (EC), trophoblast cells (TC) and basal membrane that separates between maternal and fetal blood circulations within the placenta and facilitates feto-maternal transport characteristics, which are not completely understood. METHODS: An in vitro biological model of the PB model was co-cultured of human TC (HTR8) and human umbilical vein EC (HUVEC) on both sides of a denuded amniotic membrane (AM) using custom designed wells. RESULTS: Confocal and transmission electron microscopy (TEM) imaging confirmed the morphology expressions of human EC and TC. Further support on the integrity of the new PB model was obtained from the existence of tight junctions and permeability experiments with fluorescence markers of small and large molecules. The monolayer of EC demonstrated the limiting layer for the transport resistance across this complex barrier. DISCUSSION AND CONCLUSION: This new in vitro viable model mimics the architecture of the human PB and can be used in in vitro simulations of transplacental transport studies.

A new method for analysis of non-pregnant uterine peristalsis using transvaginal ultrasound.

OBJECTIVES: To develop an objective method for analysis of uterine peristalsis using transvaginal sonography (TVS). METHODS: We performed computerized analysis of 2-5-min video recordings of TVS imaging of a midsagittal cross-section of the uterus during the proliferative and early secretory phases of 18 healthy volunteers aged 28-41 years. The contours of the fluid-endometrial interface (FEI) and the endometrium-myometrium interface (EMI) were detected in each frame, and the data from all frames were used to explore the dynamic motility characteristics of these interfaces at fixed distances from the fundus. RESULTS: The mean ± SD dominant frequency of peristalsis of the EMI along the midsagittal cross-section was 0.049 ± 0.01 Hz and that of the cavity center was 0.043 ± 0.02 Hz. The maximal amplitudes of the EMI were about 1 ± 0.25 mm, located between 7 and 17 mm from the fundus. The amplitudes of the FEI were in the range 0.05-0.2 mm. The amplitude of the cavity centerline movement was 0.94 ± 0.34 mm, located at the extremes of the unperturbed curve. CONCLUSIONS: This study provides a simple tool for analysis of uterine peristalsis characteristics using ultrasound data. This is possible at the EMI even when the FEI is invisible or incomplete, such as during the luteal phase, when an intrauterine contraceptive device is in place, and during diagnostic or medical intervention.

Anthropometry of fetal vasculature in the chorionic plate.

Normal fetal development is dependent on adequate placental blood perfusion. The functional role of the placenta takes place mainly in the capillary system; however, ultrasound imaging of fetal blood flow is commonly performed on the umbilical artery, or on its first branches over the chorionic plate. The objective of this study was to evaluate the structural organization of the feto-placental vasculature of the chorionic plate. Casting of the placental vasculature was performed on 15 full-term placentas using a dental polymer mixed with colored ink. Observations of the cast models revealed that the branching architecture of the chorionic vessel is a combination of dichotomous and monopodial patterns, where the first two to three generations are always of a dichotomous nature. Analysis of the daughter-to-mother diameter ratios in the chorionic vessels provided a maximum in the range of 0.6-0.8 for the dichotomous branches, whereas in monopodial branches it was in the range of 0.1-0.3. Similar to previous studies, this study reveals that the vasculature architecture is mostly monopodial for the marginal cord insertion and mostly dichotomous for the central insertion. The more marginal the umbilical cord insertion is on the chorionic plate, the more monopodial branching patterns are created to compensate the dichotomous pattern deficiency to perfuse peripheral placental territories.

Feto-feto-fetal transfusion syndrome in monozygotic monochorionic triamniotic triplets: vascular evaluation by a cast model.

A unique cast model of the placenta in a rare case of feto-feto-fetal triplet transfusion syndrome (FFFTTS) allowed the demonstration of why the transfusion syndrome developed in one fetus and not in the other two in that single placenta. The vasculature anatomy of a monochorionic triamniotic triplet placenta with FFFTTS of three healthy infants (one donor, two recipients) born in the 35th week of gestation was cast by means of dental casting materials. After the cast hardened, the tissue was corroded, revealing the cast blood vessels. The diameters and lengths of the chorionic blood and intraplacental vessels of the cast placenta were measured with a digital caliper. The cast revealed two artery-artery (A-A) anastomoses on the chorionic plate between the two recipients and the donor. Seven artery-vein (A-V) deep anastomoses connected only the arteries of the donor and the veins of the two recipients. The blood vessel connections among the fetuses allowed the evaluation of a pathologic case with its own control in a single placenta. From the vascular appearance, we speculate that the A-A anastomoses between the two fetuses protected them from developing blood transfusions, but that the A-V anastomoses contributed to their development.

Prediction of fetal weight by ultrasound: the contribution of additional examiners.

OBJECTIVES: To assess the contribution of additional examiners to: the average discrepancy between estimated and actual fetal weights; the correlation between estimated and actual fetal weights; the reduction in major (> 10%) discrepancies between estimated and actual fetal weights. DESIGN: Three experienced sonographers independently measured fetal biparietal diameter, head circumference, abdominal circumference and femur length in 39 fetuses at term. The estimated fetal weights were calculated for each examiner. Fetal biometric measurements were analyzed to obtain the source of differences in estimations among the examiners. Discrepancy, correlation and number of major (> 10%) discrepancies between the estimated and actual fetal weights were calculated for each examiner, and the contribution of additional examiners was analyzed. RESULTS: The differences in measurements of the biparietal diameter and femur length were lower than those of the head and abdominal circumferences. For each of the three examiners, the average discrepancy between the estimated and actual fetal weights was 6.1%, 5.9% and 6.3%. When the estimation was based on two examiners, the discrepancy decreased to 4.8-5.6%. The contribution of a third examiner was nil. Major (> 10%) discrepancies between estimated fetal weight and actual birth weight were found in seven, eight and nine estimations of the examiners. Estimation by two examiners decreased the number of major discrepancies, and estimation by all three examiners further decreased by approximately 50% the number of major discrepancies between the estimated and actual fetal weights. CONCLUSION: Measurements by multiple examiners changes only slightly the average number of discrepancies between estimated and actual fetal weights. However, the reduction in major (> 10%) discrepancies is statistically and clinically significant.

Persistent right umbilical vein: incidence and significance.

OBJECTIVES: To conduct a prospective evaluation of the incidence and neonatal outcome of fetuses with persistent right umbilical vein. This condition had traditionally been considered to be extremely rare and to be associated with a very poor neonatal prognosis, but later evidence has raised some doubts about the veracity of these contentions. METHODS: Between August 1995 and November 1998, 8950 low-risk patients were prospectively evaluated at two medical centers. The sonographic diagnosis of a persistent right umbilical vein was made in a transverse section of the fetal abdomen when the portal vein was curved toward the stomach, and the fetal gall bladder was located medially to the umbilical vein. RESULTS: Persistent right umbilical vein was detected in 17 fetuses during the study. Four of them had additional malformations, of which three had been detected antenatally. CONCLUSIONS: We established that the incidence of persistent right umbilical vein in a low-risk population is 1 : 526. We believe that the sonographic finding of this anomaly is an indication for conducting targeted fetal sonography and echocardiography. When the persistent right umbilical vein is connected to the portal system and other anomalies are ruled out, the prognosis can generally be expected to be favorable.

Effect of the supine position on uterine and umbilical blood flow during the third trimester of uncomplicated pregnancies in multiparous patients.

We established the effects of the supine position on umbilical blood flow when measured during the third trimester in 30 multiparous, normotensive patients. Blood flow in the umbilical and uterine arteries and blood pressure in the brachial and popliteal arteries were blindly taken by two different observers: first in the lateral and 5 min later in the supine position. There was a significant difference in mean blood pressure between the two postures. However, there was no statistical difference in the pulse pressure or in systolic/diastolic ratio in the umbilical and uterine arteries between the two positions. Postural changes in normotensive multiparous patients do not affect uterine and umbilical blood flow during the third trimester of uncomplicated pregnancies.

The mechanism of hydrosalpinx in embryo implantation.

BACKGROUND: Hydrosalpinx adversely affects embryo implantation and contributes to poor implantation rates post embryo transfer. Embryo transport depends on concomitant intrauterine fluid motion induced by uterine wall motility, the result of spontaneous myometrial contractions towards the fundus. METHODS AND RESULTS: The uterine dynamics of five patients with hydrosalpinx were recorded and analysed by image-processing techniques: the frequency was higher while the amplitudes and passive widths were lower compared with healthy volunteers. The existing peristaltic activity should have induced intrauterine fluid flow; however, the recordings failed to show the expected transport of fluid bolus. This observation was supported by mathematical simulations based on the hypothesis that fluid accumulation in the Fallopian tube of a patient with hydrosalpinx increases tubal pressure and thereby induces a pressure gradient between the fundus and the cervix. This pressure gradient acts adversely to the cervix-to-fundus intrauterine peristalsis and generates reflux currents that may thrust embryos away from the implantation site. CONCLUSIONS: The reflux phenomenon could explain the reduced implantation rate associated with hydrosalpinx. Resolution of the issue of whether the removal of a Fallopian tube with hydrosalpinx should be undertaken for improving IVF pregnancy rates should be accompanied by prospective randomized clinical trials.

Vascularity index distribution within the testis: a technique for guiding testicular sperm extraction.

Azoospermia is defined as the absence of spermatozoa in the ejaculate, although some foci of spermatogenesis may exist in the testes of these men. Currently, there are no clinical, seminal or hormonal parameters for identifying spermatogenesis within the testis sufficient for achieving genetic offspring. As a result, multiple biopsies are performed at several arbitrary sites of both testes in search of spermatozoa. We developed a power Doppler (PD) ultrasound (US) image-based technique that predicts sites with the greatest potential for spermatogenesis. PDUS images of the testes of azoospermic men were acquired at seven cross-sections to reconstruct a 3-D matrix for constructing a spatial map of preferential regions where spermatozoa are most likely to exist. This technique may obviate the need for arbitrary multiple biopsies that inflict some degree of damage upon testicular tissue, and may increase the success rate of identifying viable spermatozoa in testicular biopsies.

Peristaltic flow in a tapered channel: application to embryo transport within the uterine cavity.

Cyclic uterine peristalsis plays a central role in assisting the transport of sperm to the fallopian tube and later in the conception process in transporting the embryo to a fundal site for implantation. Fulfillment of these essential events within the time limits of fertilization and implantation depends on concomitant intrauterine fluid motion induced by uterine wall motility. A model of wall-induced fluid flow within a finite tapered two-dimensional channel was developed to simulate intrauterine fluid flow pattern and transport phenomena due to symmetric and asymmetric wall displacements. The analysis showed that the transport phenomena are strongly dependent on the phase shift of wall displacement and the angle between the walls. The velocities, flow rates, pressure and the axial transport of massless particles are reduced to zero when contractions are completely out of phase. Cases of reflux and trapping in a tapered channel are discussed for the first time. The reflux phenomenon is most likely to occur when wall motility is asymmetric, especially when the angle between the walls increases, while trapping is enhanced as the asymmetric motility and the angle between the channel walls decrease. The relevance of the results to intrauterine fluid transport phenomena, embryo transfer and hydrosalpinx was explored.

First trimester PAPP-A in the detection of non-Down syndrome aneuploidy.

Combined first trimester screening using pregnancy associated plasma protein-A (PAPP-A), free beta-human chorionic gonadotrophin, and nuchal translucency (NT), is currently accepted as probably the best combination for the detection of Down syndrome (DS). Current first trimester algorithms provide computed risks only for DS. However, low PAPP-A is also associated with other chromosome anomalies such as trisomy 13, 18, and sex chromosome aneuploidy. Thus, using currently available algorithms, some chromosome anomalies may not be detected. The purpose of the present study was to establish a low-end cut-off value for PAPP-A that would increase the detection rates for non-DS chromosome anomalies. The study included 1408 patients who underwent combined first trimester screening. To determine a low-end cut-off value for PAPP-A, a Receiver-Operator Characteristic (ROC) curve analysis was performed. In the entire study group there were 18 cases of chromosome anomalies (trisomy 21, 13, 18, sex chromosome anomalies), 14 of which were among screen-positive patients, a detection rate of 77.7% for all chromosome anomalies (95% CI: 55.7-99.7%). ROC curve analysis detected a statistically significant cut-off for PAPP-A at 0.25 MoM. If the definition of screen-positive were to also include patients with PAPP-A<0.25 MoM, the detection rate would increase to 88.8% for all chromosome anomalies (95% CI: 71.6-106%). This low cut-off value may be used until specific algorithms are implemented for non-Down syndrome aneuploidy.

Characteristics of uterine peristalsis in spontaneous and induced cycles.

OBJECTIVE: To characterize the dynamics of the intrauterine fluid-wall interface (IUFWI) from in vivo transvaginal ultrasound images by new techniques of image processing of sagittal cross-sections of the uterus, in healthy women with normal cycles and patients treated with clomiphen citrate (CC). DESIGN: Clinical study. SETTING: An ultrasound unit in a large university-affiliated municipal hospital. PATIENT(S): Twenty-five patients with normal spontaneous cycles (group A) and nine patients treated by CC (group B). INTERVENTION(S): Transvaginal ultrasound examinations. MAIN OUTCOME MEASURE(S): Transvaginal ultrasound images were processed to carry out a computational analysis of the resultant IUFWI. RESULT(S): The amplitude and the width of the IUFWI were higher in group B, but the ratio of these measurements was similar in both groups. The frequency of wall motility of group A was lower and its pattern was more symmetrical than that of group B. CONCLUSION(S): The differences in the dynamic characteristics of spontaneous and CC-induced cycles may constitute an additional parameter that should be considered in embryo transport.

The postnatal management of congenital cystic adenomatoid malformation.

BACKGROUND: Routine prenatal ultrasound has increased the frequency of prenatal diagnosis of congenital cystic lung malformation, such as cystic adenomatoid malformation, pulmonary sequestration, congenital lobar emphysema, and bronchogenic cyst. OBJECTIVES: To evaluate the methods of postnatal diagnosis, the optimal age for operation since surgery is always required, and the optimal extent of lung resection. METHODS: The clinical courses of 11 patients with congenital lung cysts who underwent surgical lung resection (8 lobectomies and 3 segmentectomies) were reviewed. RESULTS: The diagnosis was confirmed by computed tomography scan in all. In nine patients the diagnosis was made prenatally. Chest X-ray was normal postnatally in all patients except for two who had recurrent pneumonia. Postoperative follow-up showed excellent recovery in all operated children. One patient who underwent surgery for CCAM following episodes of severe pneumonia died from another cause 5 months later. Postoperative chest CT scan showed no residual disease in eight patients. In two who had undergone limited resection, tomography showed a small segment of residual disease in one and a suspected residual lesion in the other. CONCLUSION: With prenatal ultrasound the true frequency of congenital cystic lung anomaly appears to be higher than previously reported. Postnatal CT is mandatory to confirm or to rule out the diagnosis. The mere presence of cystic lung malformation is an indication for surgery. Complete removal of the affected lung lobe is recommended. Segmental resection may be inadequate. Early operation is tolerated well by infants and small children and we recommend that surgery be performed in children between 6 and 12 months of age.

The effect of intrauterine growth restriction on the development and health of children.

The neurodevelopmental and cognitive outcome of long-term Intrauterine Growth Restriction (IUGR) has been followed up from pregnancy to school age at the Tel Aviv Child Development Centre.

The use of prophylactic Stamey bladder neck suspension to prevent post-operative stress urinary incontinence in clinically continent women undergoing genitourinary prolapse repair.

The present study was undertaken to evaluate the efficacy of Stamey bladder neck suspension in preventing post-perative stress urinary incontinence in clinically continent women undergoing surgery for genitourinary prolapse. Thirty clinically continent women with severe genitourinary prolapse were found to have a positive stress test with re-positioning of the prolapse. They all had significant urethrovesical junction hypermobility. In addition to the genitourinary prolapse repair, these patients underwent a prophylactic Stamey procedure to prevent the possible development of post-operative stress urinary incontinence. The mean duration of follow-up was 8+/-4.5 months (range, 3-19 months). Seven (23.30%) patients developed overt post-operative stress urinary incontinence that was confirmed urodynamically. Eleven (36.7%) other patients denied stress incontinence; however, post-operative urodynamics demonstrated sphincteric incontinence. Post-operative complications were uncommon and minor. In conclusion, continent patients with a positive stress test demonstrated on re-positioning of the prolapse during pre-operative urodynamic evaluation are considered to be at high risk of developing post-operative stress urinary incontinence. In these patients, an additional, effective anti-incontinence procedure should be considered during surgical correction of genitourinary prolapse. The Stamey procedure, although simple and safe, does not appear to be the optimal solution to this clinical problem.

Is amniotic fluid volume influenced by a 24-hour fast?

OBJECTIVE: To assess the influence of fasting for 24 hours on the amniotic fluid index (AFI). STUDY DESIGN: The AFI of 22 parturients in the second trimester of uncomplicated pregnancy was evaluated on the morning after a 24-hour fast. Patients were prospectively matched to another group of 25 patients who did not fast. Both groups were reevaluated after one week. Two different observers, blind to each other's results, performed the examinations. RESULTS: A statistically significant difference was found in the AFI between the two groups on the day after fasting (11.73 +/- 2.12 versus 15.4 +/- 1.2, respectively; P < .01). After one week there was no difference in AFI between the two groups (15.35 +/- 1.2 and 15.42 +/- 1.2, respectively; P > .01). CONCLUSION: Fasting may reduce the amniotic fluid volume as shown by the AFI, and fluid intake may restore the normal amount of amniotic fluid volume.

Transvaginal sonohysterography for the evaluation and treatment of retained products of conception.

Diagnosing retained products of conception in a woman presenting with postpartum or postabortion bleeding presents a clinical challenge. Although ultrasonographic examination may be potentially useful in detecting retained products of conception, its accuracy has not yet been established. Saline infusion sonohysterography is a simple ultrasonographic technique for enhanced transvaginal sonographic imaging of the endometrial cavity by the instillation of saline into the uterine cavity during ultrasonographic evaluation. This technique enhanced our ability to diagnose retained products of conception, and we describe our experience in evacuating them under sonographic guidance while performing saline infusion sonohysterography.

Six-year follow-up of children with intrauterine growth retardation: long-term, prospective study.

This prospective study was designed to characterize the neurodevelopmental and cognitive difficulties specific to children with intrauterine growth retardation and to detect early clinical predictors of these difficulties. Eighty-one children with intrauterine growth retardation were monitored up to 6 to 7 years of age using biometric parameters, perinatal risk questionnaires, and detailed neurodevelopmental and cognitive assessments. Forty-one children served as age-matched, appropriate for gestational age controls. A significant difference in growth parameters (P < .001), neurodevelopmental score (P < .05), and IQ (P < .05) was found between the children with intrauterine growth retardation and controls. A specific profile of difficulties in coordination, lateralization, spatial and graphomotor skills, and abundance of associated movements is typical of the children with intrauterine growth retardation and hints at possible later learning disabilities. The clinical parameters best predicting neurodevelopmental outcome were the neonatal risk score (P < .05) and the weight and height at 6 years of age (P < .05). The children with intrauterine growth retardation with neonatal complications had lower neurodevelopmental scores than the controls but no difference in IQ. Intrauterine growth retardation children diagnosed prenatally had the same neurodevelopmental and IQ scores as those diagnosed at birth, probably due to the careful perinatal and obstetric care provided. Children with intrauterine growth retardation demonstrate a specific profile of neurodevelopmental disabilities at preschool age. Early diagnosis and intervention could probably reduce these difficulties to a minimum.

Timing of sonohysterography in menstruating women.

A prospective, blind study was carried out on 44 patients to evaluate the most suitable time to perform transvaginal sonohysterography. On the day of arrival at our unit, regardless of their cycle day, the women underwent sonohysterographic evaluation, which was repeated during the first 10 days of the next cycle. Patients with sonohysterographic findings underwent hysteroscopy. According to the timing of the first examination, they were divided into two groups, i.e. group 1 for the first 10 days of the cycle, and group 2 for days 16 through 28. At the end of the study the groups were compared. The results showed a false-positive rate of 27% in group 2, while no false-positive was found in group 1. We concluded that the best time for sonohysterography in patients who still have their menstrual period is during the first 10 days of the cycle.