Umbilical artery doppler sonography in Saanen goat fetuses during singleton and multiple pregnancies

The objective of this study was to evaluate the blood flow from the umbilical artery (UA) in healthy pregnant goats. Doppler sonography examinations were performed every two weeks in Saanen goats with a singleton (n = 5) or multiple (n = 4) pregnancy from 40 to 145 days of gestation. Fetal heart rates (FHR), pulsatility index (PI), and resistance index (RI) were recorded from the mid-cord site of the free-floating umbilical cord. FHR decreased gradually as the pregnancy progressed and significantly decreased during the last two examinations of all fetuses (P < 0.05). The mean PI level was dramatically different (P < 0.05) until 85 days of gestation, after which it reached a plateau level until parturition. Similar to PI, RI decreased by 85 days of gestation (P < 0.05), and decreased again by 130s gestation. No reverse or absent end-diastolic flow were observed in fetuses during any examinations. When comparing singleton and multiple pregnancies, there were no significant differences in UA pulsatility or resistance in fetuses seen. The middle of the second trimester was observed to be a threshold stage for indices in the pattern of caprine pregnancy. In conclusion, this work provides additional values that might be useful when evaluating singleton and multiple pregnancies, and may be evaluated in further studies regarding fetal monitoring.

The fetal venous system, part I: normal embryology, anatomy, hemodynamics, ultrasound evaluation and Doppler investigation

Since its introduction in the mid-1980s sonographic evaluation of the human fetal venous system has advanced dramatically. The venous system is well-recognized as a target for investigation in cases of circulatory compromise, and a broad spectrum of malformations affecting this system has been described. Appreciation of the normal embryology, anatomy and physiology of this system is essential to an understanding of structural anomalies and the sequential changes encountered in intrauterine growth restriction or other developmental disorders. We review the normal embryology, anatomy, and hemodynamics of the human fetal venous system, and provide an overview of Doppler investigation, as well as three- and four-dimensional ultrasound modalities and their application to this system.

Fetal topographical anatomy of the pancreatic head and duodenum with special reference to courses of the pancreaticoduodenal arteries

PURPOSE

The purpose of this study is to provide better understanding as to how the "double" vascular arcades, in contrast to other intestinal marginal vessels, develop along the right margin of the pancreatic head.

MATERIALS AND METHODS

In human fetuses between 8-30 weeks, we described the topographical anatomy of the vessels, bile duct, duodenum as well as the ventral and dorsal primordia of the pancreatic head with an aid of pancreatic polypeptide immunohisto-chemistry.

RESULTS

The contents of the hepatoduodenal ligament crossed the superior side of the pylorus. Moreover, the right hepatic artery originating from the superior mesenteric artery ran along the superior aspect of the pancreatic head. An arterial arcade, corresponding to the posterior pancreaticoduodenal arteries, encircled the superior part of the pancreatic head, whereas another arcade, corresponding to the anterior pancreaticoduodenal arteries, surrounded the inferior part. The dorsal promordium of the pancreas surrounded and/or mixed the ventral primordium at 13-16 weeks. Thus, both arterial arcades were likely to attach to the dorsal primordium.

CONCLUSION

The fetal anatomy of the pancreaticoduodenal vascular arcades as well as that of the hepatoduodenal ligament were quite different from adults in topographical relations. Thus, in the stage later than 30 weeks, further rotation of the duodenum along a horizontal axis seemed to be required to move the pylorus posterosuperiorly and to reflect the superior surface of the pancreatic head posteriorly. However, to change the topographical anatomy of the superior and inferior arterial arcades into the final position, re-arrangement of the pancreatic parenchyma might be necessary in the head.

Anatomophysiologic basis of tetralogy of Fallot and its clinical implications

Tetralogy of Fallot is the most frequent cyanotic congenital cardiopathy. Its physiopathology has been progressively described which has made better treatment possible. The four characteristic morphologic abnormalities are: interventricular communication, subpulmonary stenosis, biventricular origin of the aortic valve and right ventricular hypertrophy, which are the direct result of the antero-cephalad deviation of the ventricular septal outlet and hypertrophy of the septoparietal trabeculations. These anatomic abnormalities result in decreased pulmonary blood flow, leading to hypoxia and cyanosis. The main determinants of pulmonary blood flow are the source of the blood flow to the lungs, the severity and functional behaviour of the subpulmonary obstruction, the right ventricular and arterial systemic pressures and the ductus arteriosus. The mechanism of cyanotic spells is not clear. Increases in infundibular contractility, peripheral vasodilatation and right ventricular mechanoreceptor stimulation are some of the proposed mechanisms. There are two surgical strategies in newborns/children: a staged approach (with a palliative procedure followed by the complete repair) or early complete repair. There are arguments for and against each of these strategies, and the debate about the ideal treatment continues. In conclusion, the correct understanding of this cardiopathy's physiopathology is essential to improving the child's treatment. This review is particularly contemporary and relevant issue because one must always bear in mind the physiopathology of the original disease in order to correctly follow-up a new patient population: adults with surgically corrected Tetralogy of Fallot.

Barrier capacity of human placenta for nanosized materials

BACKGROUND

Humans have been exposed to fine and ultrafine particles throughout their history. Since the Industrial Revolution, sources, doses, and types of nanoparticles have changed dramatically. In the last decade, the rapidly developing field of nanotechnology has led to an increase of engineered nanoparticles with novel physical and chemical properties. Regardless of whether this exposure is unintended or not, a careful assessment of possible adverse effects is needed. A large number of projects have been carried out to assess the consequences of combustion-derived or engineered nanoparticle exposure on human health. In recent years there has been a growing concern about the possible health influence of exposure to air pollutants during pregnancy, hence an implicit concern about potential risk for nanoparticle exposure in utero. Previous work has not addressed the question of whether nanoparticles may cross the placenta.

OBJECTIVE

In this study we investigated whether particles can cross the placental barrier and affect the fetus.

METHODS

We used the ex vivo human placental perfusion model to investigate whether nanoparticles can cross this barrier and whether this process is size dependent. Fluorescently labeled polystyrene beads with diameters of 50, 80, 240, and 500 nm were chosen as model particles.

RESULTS

We showed that fluorescent polystyrene particles with diameter up to 240 nm were taken up by the placenta and were able to cross the placental barrier without affecting the viability of the placental explant.

CONCLUSIONS

The findings suggest that nanomaterials have the potential for transplacental transfer and underscore the need for further nanotoxicologic studies on this important organ system.

Effects of sildenafil on maternal hemodynamics and fetal growth in normal rat pregnancy

It has been suggested that the phosphodiesterase-5 (PDE5) inhibitor sildenafil may be useful in the treatment of hypertension during pregnancy. However, we have reported a selective increase in renal inner medullary PDE5 that participates in the sodium retention of pregnancy. Therefore, the purpose of this study was to determine whether oral sildenafil treatment impairs maternal plasma volume expansion and/or fetal growth during rat pregnancy. Rats received sildenafil (10 mg x kg(-1) x day(-1), 50 mg x kg(-1) x day(-1), or 90 mg x kg(-1) x day(-1)) or vehicle on days 4-20 of pregnancy. On days 14-19, rats were housed in metabolic cages for collection of urine and measurement of food and water intake. Terminal hemodynamic and fetal measurements were taken on day 20. None of the sildenafil doses lowered blood pressure, and although all doses increased plasma cGMP concentrations, only the highest dose increased aortic and inner medullary cGMP content. Sildenafil had no effect on maternal weight gain; however, the highest dose decreased both plasma volume and renal sodium retention. The pup number and size were similar among the groups. Therefore, these studies suggest that low doses of systemic sildenafil may be safe during pregnancy in the rat, but higher doses may interfere with the physiological sodium retention and volume expansion of pregnancy. The effects of systemic sildenafil on blood pressure and sodium retention during hypertension in human pregnancy remain to be examined.

[Evaluation of the relation between Doppler flow in maternal and fetal vessels and the risk of adverse neonatal outcome]

AIM

The study aimed at: 1. Analysis of the relationship between Doppler flow in the selected maternal and fetal vessels and the risk of adverse perinatal outcome (APO); 2. Multivariate logistic regression model for the assessment the risk of APA.

MATERIAL AND METHODS

The study population covered 216 pregnant women from Lodz and Kalisz between 2003-2006.

RESULTS

In univariate logistic regression model PI_UA significantly influenced the risk of APO. That risk was increasing 1.2 times, if the PI_UA value was 1/10th higher than the measured unit. Abnormal cardiotocography (CTG) pattern was related to 12-times higher risk of APO. In cases of abnormal PI_MCA, the risk of APO was 2.5 times higher than when PI_MCA was within the normal range. Abnormal PI_UA was related to 11.5-times higher risk of APO. Similarly when PIV_DV was abnormal, the risk of APO was 2.3-times higher. Low birth weight (LBW) was connected with the 6-times higher risk of APO. In multivariate logistic regression model, CTG and LBW were the risk factors significantly associated with APA. Abnormal CTG pattern was related to more than 6-times higher increase of the risk of APO, however LBW with nearly 4-times higher risk of APO.

CONCLUSION

Abnormal values of PI in UA and in MCA, abnormal flow in DV and abnormal CTG pattern, as well as low birth weight, had significant influence on the risk of APO. In multivariate analysis only abnormal CTG and low birth weight were the significant factors of APO.

[A woman with an obstetric curiosity]

A primipara underwent a caesarean section for preeclampsia. It so happened that vasa praevia were seen during the operation. A healthy boy was born.

[Fetal circulation in normal pregnancy and in placental insufficiency]

The fetal circulation is different from the adult circulation. One of the quite common conditions that are challenging to the developing fetus is placental hypoxia. Regardless of its cause, placental vascular insufficiency is commonly assumed to be an important factor in the development of intrauterine growth retardation. Several mechanisms are involved in the fetal adaptation to the decompensation during hypoxemia. Doppler Ultrasound technologies can help to evaluate of the fetal wellbeing.

[Femoral bone morphogenesis in human fetuses in the area of environmental fluoride pollution]

The aim of this study was to determine the peculiarities of femoral bone osteogenesis in human fetuses in the areas with different levels of environmental pollution with fluoride compounds (the city of Irkutsk and the town of Shelekhov). The histological structure of femoral bones was studied in 70 fetuses aged 15-16, 19-20, 22-25 and 27-29 gestational weeks. Morphometric methods were used to evaluate the number of blood vessels per total area of epiphysis, the length of endochondral trabeculae, the thickness of hypertrophic and columnar cartilage zones, diaphysis wall and its trabeculae thickness, the thickness of endochondral trabeculae merging with the diaphysis wall, and of the bone growing on the epiphysis. It was found that in the city of Irkutzk, relatively remote from the pollution source, the processes of osteogenesis and osteoresorption are balanced and are characterized by the prevalence of osteoblastic activity over osteoclastic activity, ensuring the active bone growth. During weeks 15-22, the bones are actively growing in length, while during weeks 22-29 they grow mainly in width. In the town of Shelekhov, located closely to the pollution source, the growth of bones in both length and width, is delayed. The bone growth was active till week 16, however, during weeks 18-29, osteoresorption prevailed over the osteosynthesis, the bone thickness decreased, while the activity of their growth in length remained reduced.

Fetal and maternal angiogenic/anti-angiogenic factors in normal and preeclamptic pregnancy

Few studies evaluated angiogenic/anti-angiogenic factors and endothelial (dys)function in both maternal and umbilical cord blood (UCB) in preeclampsia (PE). We aimed to clarify the role of placental growth factor (PlGF), vascular endothelial growth factor (VEGF), soluble vascular endothelial growth factor receptor 1 (VEGFR-1) and tissue plasminogen activator (tPA), by evaluating them in maternal and UCB in 42 normal and 46 preeclamptic (PEc) cases. In PE, maternal and UCB PlGF were significantly lower; maternal VEGF, sVEGFR-1 and tPA were significantly higher. In UCB, sVEGFR-1 and tPA were significantly higher in PEc cases, while VEGF and PlGF were significantly lower. A significant correlation between maternal and UCB sVEGFR-1, and between sVEGFR-1 and tPA both in maternal and UCB, was observed in PEc cases. In maternal and UCB circulation in PE, a close interaction seems to exist between endothelial dysfunction and angiogenesis disturbance, and sVEGFR-1 seems to play a central role in those disturbances.

BOLD MRI in sheep fetuses: a non-invasive method for measuring changes in tissue oxygenation

OBJECTIVE

The purpose of this descriptive study was to correlate changes in the blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) signal with direct measurements of fetal tissue oxygenation.

METHODS

Seven anesthetized ewes carrying singleton fetuses at 125 days' gestation (term 145 days) underwent BOLD MRI, covering the entire fetus in a multislice approach. The fetuses were subjected to normoxic, hypoxic and hyperoxic conditions by changing the O(2)/N(2)O ratio in the maternal ventilated gas supply. The partial pressure of oxygen (pO2) in the fetal liver was measured using an oxygen-sensitive optode. Maternal arterial blood samples were simultaneously withdrawn for blood gas analysis. These measurements were compared with BOLD MRI signals in the fetal liver, kidney, spleen and brain.

RESULTS

We demonstrated a consistent increase in the BOLD MRI signal with increasing tissue pO(2). For the fetal liver, spleen and kidney we observed a clear association between changes in maternal arterial blood pO2 and changes in BOLD MRI signal. Interestingly, we found that the BOLD signal of the fetal brain remained unchanged during hypoxic, normoxic and hyperoxic conditions.

CONCLUSIONS

This experimental study demonstrated that BOLD MRI is a reliable non-invasive method for measuring changes in tissue oxygenation in fetal sheep. The unchanged signal in the fetal brain during altered maternal oxygen conditions is probably explained by the brain-sparing mechanism.

[Do abnormal results of Doppler examinations in fetuses with growth restriction increase the frequency of postnatal complications of the central nervous system and gastrointestinal tract?]

OBJECTIVES

The aim of the work was to assess the correlations between the results of antenatal Doppler examinations in fetuses with growth restriction (IUGR) and the frequency of postnatal complications of central nervous system and gastrointestinal tract.

MATERIAL AND METHODS

47 pregnant women and 47 fetuses and newborns from singleton pregnancies with diagnosed intrauterine growth restriction. Two groups of fetuses (newborns) were distinguished based on serial Doppler examinations of fetal umbilical and middle cerebral arteries: 1) newborns with IUGR and abnormal results of antenatal Doppler examinations (group 1); 2) newborns with IUGR and normal results of antenatal Doppler examinations (group 2). The analysis concerned such neonatal complications as intraventricular hemorrhages (IVH) of III and IV degree, leucomalacias and necrotizing eneterocollits (NEC).

RESULTS

Among 47 neonates, the abnormal results of Doppler examinations were found in 21 of them, and in the rest of the newborns (26) there were no abnormalities in Doppler antenatal examinations. The frequency of intraventricular hemorrhages of III and IV degree, neonatal leucomalacias and necrotizing eneterocollits did not differ significantly between the groups. The mean time of hospitalization in newborns with abnormal results of antenatal Doppler examinations was significantly longer than in neonates whose antenatal Doppler tests were normal (14 days vs 10 days). The newborns from group 1 required parenteral feeding significantly more often than the newborns from group 2 (28.9% vs 12%).

CONCLUSIONS

The comparable frequency of central nervous system complications in newborns with abnormal and in neonates with normal results of antenatal Doppler examinations may indicate on effective role of brain sparing effect in fetuses with IUGR as a mechanism which reduces the likelihood of hypoxemic complications in the developing fetal brain. The newborns with IUGR and abnormal results of antenatal Doppler test require both a longer hospitalization and the necessity of parenteral feeding when compared with newborns with IUGR and normal antenatal Doppler test results. Newborns who were diagnosed with absent or reversed end-diastolic flow in umbilical artery are particularly at risk of central nervous system complications.

Obstetric management of intrauterine growth restriction

The aim of obstetric management is to identify growth-restricted foetuses at risk of severe intrauterine hypoxia, to monitor their health and to deliver when the adverse outcome is imminent. After 30-32 gestational weeks, a Doppler finding of absent or reverse end-diastolic flow in the umbilical artery of a small-for-gestational age foetus is in itself an indication for delivery. In very preterm foetuses, the intrauterine risks have to be balanced against the risk of prematurity. All available diagnostic information (e.g., Doppler velocimetry of umbilical artery, foetal central arteries and veins and of maternal uterine arteries; foetal heart rate with computerised analysis of short-term variability; amniotic fluid amount; and foetal gestational age-related weight) should be collected to support the timing of delivery. If possible, the delivery should optimally take place before the onset of late signs of foetal hypoxia (pathological foetal heart rate pattern, severely abnormal ductus venosus blood velocity waveform, pulsations in the umbilical vein).

Middle cerebral artery peak systolic velocity and ductus venosus velocity in the investigation of nonimmune hydrops

PURPOSE

This study was performed to investigate the cause of nonimmune hydrops fetalis by measuring the peak systolic velocity (PSV) in the middle cerebral artery (MCA) and velocity waveforms of the ductus venosus (DV) with Doppler.

METHODS

This cross-sectional study was done on 19 pregnancies referred to three university teaching hospitals for further investigation of nonimmune hydrops fetalis in 2007 and 2008. The MCA-PSV and DV velocity waveforms were recorded in all fetuses. Anemia was investigated in cases with MCA-PSV values greater than 1.50 MoM (multiple of the median). Cardiovascular causes and chromosomal abnormalities were investigated in fetuses with abnormal DV velocity.

RESULTS

Four of 19 fetuses had MCA-PSV values greater than 1.50 MoM. The causes of anemia were cytomegalovirus, parvovirus B19 infections, congenital heart disease, and Turner syndrome. Four cases had reversed flow in the DV; three of them had congenital heart disease on echocardiography; and one had a normal echocardiogram, but an abnormal karyotype was detected.

CONCLUSION

Assessment of the MCA-PSV and DV velocity waveforms during sonographic examination of fetuses with nonimmune hydrops fetalis may improve our knowledge about the etiology of this condition.

[Comparison of Doppler flow in selected maternal and fetal vessels in pregnancies with fetal intrauterine growth restriction]

OBJECTIVES

The aim of the study was to compare Doppler flows in materno-fetal circulation in pregnancies with IUGR and small for gestational age (SGA) neonatal weight or normal weight, as well as in uncomplicated pregnancies.

MATERIAL AND METHODS

The study population comprised 216 pregnant women from Lodz and Kalisz between 2003-2006. In the group I we included 68 women with IUGR observed in prenatal ultrasound examination and SGA neonates, in the group II--29 women with IUGR observed in US but normal neonatal weight and in the group III--110 women with normal fetal and neonatal weight.

RESULTS

Mean fetal weight in the group II was (2035 g +/- 400 g) and in the group I (1947 g +/- 414 g) and it was lower than in the group III (2765 g +/- 543 g) (p<0.0005). Notch in UTA was found more often in the group I (39.7%), than in the groups III (8.4%) and II (10.3%), (p< 0.0005). The mean PI in the right UTA in the group I (0.957 +/- 0.440) was higher than in the groups II (0.718 +/- 0.259) and III (0.730 +/- 0.215), (p<0.001). Abnormal Doppler flows in MCA in the groups I (39.7%) and II (34.5%) were observed more often than in the group III (6.4%), (p<0.0005). Similarly abnormal Doppler examination in DV in the groups I (45.5%) and II (46.4%) were observed more often than in the group III (17.8%), (p<0.0005). PI in UA in the groups I (1.061+/- 0.325) and II (0.965 +/- 0.184) was higher than in the group III (0.848 +/- 0.166), (p<0.0005).

Search for hemodynamic compromise at 11–14 weeks in monochorionic twin pregnancy: Is abnormal flow in the ductus venosus predictive of twin–twin transfusion syndrome?

BACKGROUND AND OBJECTIVES

Twin-twin transfusion syndrome is a devastating complication of monochorionic twin pregnancies. The presence of increased nuchal translucency thickness (NT) in one of the monochorionic twins has been associated with an increased risk of developing this syndrome. One of the most plausible mechanisms for increased nuchal translucency is heart failure, indirectly manifested by abnormal blood flow in the ductus venosus. We aimed to clarify the pathophysiology of increased NT found more frequently in monochorionic twins prone to develop twin-twin transfusion syndrome.

DESIGN

We present 50 cases of monochorionic twin pregnancies in which nuchal translucency thickness was measured and ductus venosus blood flow evaluation was performed at 11-14 weeks of gestation.

RESULTS

Whenever the fetuses of a twin pregnancy were found to have discrepant nuchal translucency thickness measurements and abnormal flow in the ductus venosus was found in the fetus with increased nuchal translucency thickness, twin-twin transfusion syndrome eventually developed. Progression to twin-to-twin transfusion syndrome was not observed in the twins displaying no intertwin difference in nuchal translucency thickness measurements and it was not observed in those with discrepant nuchal translucency thickness but normal flow in the ductus venosus of both fetuses. In the two cases which developed twin-to-twin transfusion syndrome, fetoscopic laser coagulation of the vascular anastomoses was successfully carried out at 18 weeks and normalization of the venous return was recorded.

CONCLUSIONS

Both increased nuchal translucency and abnormal flow in the ductus venosus in monochorionic twins may be early manifestations of haemodynamic imbalance between donor and recipient. The combined evaluation of both parameters in monochorionic twin pregnancies may constitute an effective method for identifying those at risk of developing twin-to-twin transfusion syndrome.

Prolonged morphine exposure in utero causes fetal and placental vasoconstriction: A case report

Vasoconstriction was observed in the fetal middle cerebral and umbilical arteries by Doppler assessment at 27 weeks gestation in a patient requiring continuous morphine infusion for pain control. Fetal heart tracings were also concerning. Fetal status improved after a change to fentanyl infusion, a shorter acting opioid. Caution is recommended when long-term chronic narcotic infusion is used in pregnancy.

Middle cerebral artery blood flow in the fetus and central nervous system complications in the neonate

OBJECTIVE

To evaluate the ability of blood flow (S/D) ratios in the fetal middle cerebral artery (MCA) to predict the occurrence of central nervous system (CNS) complications (bleeding and/or ischemia) in the neonate, and compare MCA flow to other tests of fetal well-being.

STUDY DESIGN

This was a retrospective, observational, cross-sectional clinical outcome study of high-risk patients, evaluated in the Perinatal Center of the author's institution, who underwent antenatal testing with non-stress test (NST) and Doppler studies (including studies of the fetal umbilical artery and MCA) within 1 week of delivery. MCA flow was converted to multiples of the mean, and appropriate parametric and non-parametric statistics were used to compare MCA flow to the presence or absence of CNS complications. Comparisons were also made for the other tests of fetal well-being.

RESULTS

CNS complications occurred only in infants who were delivered at less than 37 weeks of gestation (n = 14/131) and the analysis was limited to these 131 patients. Univariant analysis showed that only the NST correlated with CNS complications (OR = 5.46 (1.48-22.16)) and logistic regression confirmed the association. Neither increased diastolic flow in the MCA nor the presence of shunting correlated with CNS complications.

CONCLUSIONS

This study confirms previous reports that fetal shunting, with decreased resistance and increased flow in the CNS, is a benign adaptive mechanism for the fetus under stress and not an increased risk for CNS complications. A non-reactive NST, however, is a very late sign of fetal compromise and is significantly associated with the risk of developing CNS complications.

The significance of visualising coronary blood flow in early onset severe growth restricted fetuses with reverse flow in the ductus venosus

OBJECTIVE

To evaluate the incidence and significance of coronary blood flow visualisation in early onset severe intrauterine growth restriction (IUGR) fetuses and to assess its relationship with the presence of reverse flow in ductus venosus (DV).

METHODS

The examination of coronary artery was performed at a gestational age <26 weeks in 19 IUGR fetuses from mothers without medical complications and characterised by the presence of reverse flow in DV. Visualisation or non-visualisation of coronary circulation were compared with fetal and neonatal outcome.

RESULTS

Coronary flow was seen in 7/19 (36.8%) of the IUGR fetuses and these fetuses showed a higher incidence of fetal death (71.4%vs. 16.6%, p = 0.044), delivery or fetal death at an earlier gestational age (23.71 vs. 26.57 weeks, p = 0.011) and a lower birthweight (310 vs. 586 g, p = 0.011). Kaplan-Meier survival analysis demonstrated that visualisation or non-visualisation of coronary flow in such fetuses provides an independent contribution in the prediction of the time interval between Doppler study and delivery or fetal death (chi square = 15.36, p < 0.001).

CONCLUSIONS

Visualisation of coronary flow in IUGR fetuses with reverse flow in the DV identifies a subgroup of fetuses with a poorer fetal and neonatal outcome.

Acute effect of cigarette smoking on placental circulation - a study by carbon-monoxide measurement and Doppler assessment

OBJECTIVE

Carbon-monoxide (CO) decreases placental vascular impedance. We assessed the consequences of smoking-induced temporary maternal CO-increase on fetal and placental circulation.

STUDY DESIGN

In a prospective study twenty-nine smoking pregnant women and their fetuses were evaluated. We determined the changes in maternal blood CO levels after smoking, and the concomitant changes in maternal and fetal circulation. Changes in fetal heart rate, uterine artery (UTA), middle cerebral artery (MCA), and descending aorta (DA) flow were measured by Doppler velocimetry. Changes in maternal CO level and umbilical flow value were assessed by paired t-test. The correlation between CO level and placental flow was assessed by partial correlation test.

RESULTS

CO level increased (mean +/-SD 1.7 +/- 0.065% vs. 2.36 +/- 0.89, p<0.0001). Nicotine-related maternal circulatory parameters changed significantly, but uterine flow values remained unchanged. Fetal heart rate increased, while flow in MCA and DA showed no change. CO-dependent umbilical artery impedance remained unchanged (Pulsatility Index: 0.956 +/- 0.18 vs. 0.948 +/- 0.21). Partial correlation between CO level and umbilical arterial impedance showed no significance (r:-0.324).

CONCLUSION

Despite significant CO elevation, the mainly CO-regulated placental flow remained unchanged.

Foetal peak systolic velocity in the middle cerebral artery: an Asian reference range

INTRODUCTION

The aim of this study was to establish reference values of peak systolic blood flow velocity measurement in the foetal middle cerebral artery (MCA-PSV) in the local Asian obstetric population and to compare our reference ranges with those of previously-published studies.

METHODS

329 normal pregnant women attending the outpatient antenatal clinics of the Department of Obstetrics and Gynaecology in the Singapore General Hospital underwent Doppler ultrasonography at least once between 16 and 40 weeks' gestation. The blood flow velocity recordings from the foetal middle cerebral artery were obtained. New reference ranges were constructed by regressing each parameter on gestational age.

RESULTS

New reference ranges for foetal middle cerebral artery with gestation were constructed for an Asian population. Our reference curves were compared with that of a previously-constructed one.

CONCLUSION

MCA-PSV increases with advancing gestational age. There appear to be differences between Asian and non-Asian reference ranges for MCA-PSV.

The study of arterial anastomoses in the region of the alveolar process and the anterior maxilla wall in foetuses

The anterior maxilla wall and alveolar process are covered by the arterial network. Procedures in this region can cause heavy bleeding. Knowledge of the anatomical course of a particular artery is essential for performing surgery in this area. The aim of this study was to search for and then analyse anastomoses between the infraorbital and posterior superior alveolar artery. In the study, 19 maxillas of foetuses were analysed. The arteries were injected with coloured latex. The dissection was carried out using a surgical microscope and microsurgical equipment. The lower eyelid with cheek skin was separated and the facial muscles were cut to expose the maxilla and arteries of the alveolar process. The study revealed that in 10 out of 19 of the specimens there was an arterial connection between the infraorbital and posterior superior alveolar artery. The course of the analysed anastomosis was diverse. In all cases we observed an anterior superior alveolar artery. In all specimens the alveolar process was vascularised by many arteries originating from the analysed anastomosis. The location of the analysed anastomosis can be stated before operation, on the line between the medial eye angle and the sixth tooth of the same side. The anastomosis described in the study means that caudally running arteries are important in choosing incisions in procedures performed at the alveolar process.

Effect of fetal gender on ductus venosus pulsatility index and diameter at gestational age 17-37 weeks

OBJECTIVE

Recent findings have suggested that ductus venosus blood flow in the first trimester may be influenced by fetal gender. The aim of the present study was to investigate further the influence of fetal gender on ductus venosus (DV) pulsatility index (PI) and diameter at gestational age 17-37 weeks.

MATERIAL AND METHOD

This was a cross-sectional study. Three measurements were made for each the DV PI and diameter in each fetus during fetal quiescence. Statistical Package for the Social Sciences 14.0 software was used to create nomograms for the DV PI and diameter against gestational age in each gender group. The DV PI and diameter were compared between fetal genders using independent Student's t-test.

RESULTS

There was no statistically significant difference in the DV PI and diameter between fetal sexes.

CONCLUSION

Fetal gender does not influence the DV PI and diameter at gestational age 17-37 weeks.

Effects of chronic hypoglycemia and euglycemic correction on lysine metabolism in fetal sheep

In this study, we determined rates of lysine metabolism in fetal sheep during chronic hypoglycemia and following euglycemic recovery and compared results with normal, age-matched euglycemic control fetuses to explain the adaptive response of protein metabolism to low glucose concentrations. Restriction of the maternal glucose supply to the fetus lowered the net rates of fetal (umbilical) glucose (42%) and lactate (36%) uptake, causing compensatory alterations in fetal lysine metabolism. The plasma lysine concentration was 1.9-fold greater in hypoglycemic compared with control fetuses, but the rate of fetal (umbilical) lysine uptake was not different. In the hypoglycemic fetuses, the lysine disposal rate also was higher than in control fetuses due to greater rates of lysine flux back into the placenta and into fetal tissue. The rate of CO2 excretion from lysine decarboxylation was 2.4-fold higher in hypoglycemic than control fetuses, indicating greater rates of lysine oxidative metabolism during chronic hypoglycemia. No differences were detected for rates of fetal protein accretion or synthesis between hypoglycemic and control groups, although there was a significant increase in the rate of protein breakdown (P<0.05) in the hypoglycemic fetuses, indicating small changes in each rate. This was supported by elevated muscle specific ubiquitin ligases and greater concentrations of 4E-BP1. Euglycemic recovery after chronic hypoglycemia normalized all fluxes and actually lowered the rate of lysine decarboxylation compared with control fetuses (P<0.05). These results indicate that chronic hypoglycemia increases net protein breakdown and lysine oxidative metabolism, both of which contribute to slower rates of fetal growth over time. Furthermore, euglycemic correction for 5 days returns lysine fluxes to normal and causes an overcorrection of lysine oxidation.

Pregnancy outcome after ultrasound diagnosis of fetal intra-abdominal umbilical vein varix

OBJECTIVES

Fetal intra-abdominal umbilical vein (FIUV) varix is a focal dilatation of the intra-abdominal portion of the umbilical vein, which has been reported to be associated with intrauterine death and other anomalies. Our aim was to examine our experience with this diagnosis at a single tertiary-care center and to correlate it with clinical outcome.

METHODS

This was a retrospective case series study. Our ultrasound database was searched for all cases with a diagnosis of FIUV varix identified at our facility between 1997 and 2007. We reviewed all ultrasound examinations, maternal antenatal records, delivery records and newborns' medical records.

RESULTS

We identified 52 cases of FIUV among a population of approximately 68,000. Three cases of trisomy 21 were identified, all of which were accompanied by other anomalies. There was intrauterine death of one fetus with trisomy 21 at 35 weeks of gestation. We did not find an association between FIUV varix and other obstetric complications.

CONCLUSIONS

The outcome of pregnancies with FIUV varix is generally favorable. The finding of a FIUV varix should prompt the search for other anomalies, especially markers of aneuploidy.

Cortisol infusion in late-gestation hypothalamo-pituitary disconnected sheep fetus restores pituitary cell responsiveness to arginine vasopressin

Corticotrophs in the fetal sheep become increasingly responsive to arginine vasopressin (AVP) in late gestation. We previously reported that this may be due in part to corresponding increases in signal transduction (inositol 1,4,5-trisphosphate, IP(3)). These ontogenic changes are prevented by hypothalamo-pituitary disconnection (HPD), which also prevents fetal plasma cortisol concentrations from increasing in late gestation. This led us to hypothesize that cortisol is involved in mediating the changes in pituitary responsiveness. HPD was performed on fetal sheep at 120 days gestational age (dGA). Half of the HPD fetuses were infused with cortisol for 3 days beginning at 135-137 dGA (HPD+C). The remaining HPD fetuses and a group of sham-operated control fetuses were infused with saline. Pituitary cells were isolated and cultured. After 48 h, a subset of cells was stimulated with 100 nM AVP for 2 h, and the medium was collected for ACTH analysis. Another subset of cells was stimulated with 100 nM AVP for 30 min, and the formation of IP(3) was determined. Plasma cortisol concentrations increased rapidly within the first 6 h after infusion (5.2 +/- 1.9 to 29.7 +/- 4.9 ng/ml) but did not increase thereafter. Cells from HPD+C and sham-operated fetuses secreted significantly more ACTH than those from HPD fetuses (% increase from control: 33.0 +/- 8.8%, 47.9 +/- 10.6%, and 11.9 +/- 2.4%, respectively). IP(3) formation was significantly increased in cells from HPD+C and sham-operated compared with HPD fetuses (% increase from control: 17.7 +/- 4.4%, 18.9 +/- 4.3%, and 4.6 +/- 1.5%, respectively). These findings support the idea that cortisol plays a role in mediating the increase in pituitary responsiveness to AVP in the late-gestation fetal sheep.

Prediction of perinatal outcomes in patient with pre-eclampsia: maternal hyperoxygenation test on fetal Doppler flow

OBJECTIVE

Investigate if the maternal hyperoxygenation test in pregnancy with pre-eclampsia could be used for prediction of perinatal outcomes.

MATERIAL AND METHOD

Fifty-four singleton pre-eclampsia pregnant women were enrolled in the present study. Positive hyperoxygenation test was defined as an increase of the middle cerebral artery (MCA) or the ductus venosus (DV) pulsatility index (PI), or a decrease of the uterine artery or the umbilical artery (UA) PI by at least 20%. Results of hyperoxygenation test were analyzed for the correlation with perinatal outcomes.

RESULTS

Fetuses with positive hyperoxygenation test of the MCA had a birth weight less than the negative group significantly. Furthermore, there was a significantly higher rate ofsmall for gestational age (SGA) neonates and admission to the neonatal intensive care unit (NICU) in cases with positive test of the MCA.

CONCLUSION

The present study shows the correlation of positive hyperoxygenation test of the MCA and low birth weight, SGA, and NICU admission.

Doppler waveform indices of fetal middle cerebral artery in normal 20 to 40 weeks pregnancies

BACKGROUND

One of the main methods for evaluation of fetal well-being is analysis of Doppler flow velocity waveform of fetal vessels. Evaluation of Doppler wave of the middle cerebral artery can predict most of the at-risk fetuses in high-risk pregnancies. In this study, we tried to determine the normal ranges and their trends during pregnancy of Doppler flow velocity indices (resistive index, pulsatility index, systolic-to-diastolic ratio, and peak systolic velocity) of middle cerebral artery in 20 - 40 weeks normal pregnancies in Iranians.

METHODS

In this cross-sectional study, 1037 women with normal pregnancy and gestational age of 20 to 40 weeks were investigated for fetal middle cerebral artery Doppler examination.

RESULTS

Resistive index, pulsatility index, and systolic-to-diastolic ratio values of middle cerebral artery decreased in a parabolic pattern while the peak systolic velocity value increased linearly with progression of the gestational age. These changes were statistically significant (P<0.001 for all four variables) and were more characteristic during late weeks of pregnancy. The mean fetal heart rate was also significantly (P<0.001) reduced in correlation with the gestational age.

CONCLUSION

Doppler waveform indices of fetal middle cerebral artery are useful means for determining fetal well-being. Herewith, the normal ranges of Doppler waveform indices for an Iranian population are presented.

Doppler flowmetry in preeclampsia

The purpose of this study was to summarize the new published data on the Doppler flowmetry in preeclampsia.

METHODS

We summarize the new published data on the Doppler flowmetry in uteroplacental, fetoplacental and fetal circulation in preeclampsia. The present review summarized the results of clinical research on the Doppler flowmetry in the screening of risk of preclampsia, in the diagnosis of preclampsia and in the fetal risk in preclampsia (Ref. 19). Full Text (Free, PDF) www.bmj.sk.

Cardiac output following fetoscopic coagulation of major placental vessels in fetal sheep

OBJECTIVES

To measure changes in cardiac output (CO) after partial cord occlusion in fetal sheep in order to investigate pathophysiological fetal adaptation mechanisms in a simulated acute placental insufficiency model under standardized conditions, with the aim of finding relevant methods for monitoring human fetuses during stress situations.

METHODS

We used minimally invasive, percutaneous endoscopic techniques to close umbilical vessels in mid-gestational fetal sheep. Placental blood flow was reduced by preferentially closing first arterial and then the concomitant venous umbilical vessels within a short time interval. The investigations were carried out on 11 pregnant ewes at a median gestational age of 86 (range, 73-95) days. Major placental arteries and veins were occluded permanently by coagulation with bipolar forceps under percutaneous fetoscopic control. The fetal CO and Doppler parameters in the ductus venosus (DV), umbilical artery (UA) and umbilical vein (UV) were measured.

RESULTS

In spite of heart rate reduction, the CO was not significantly affected by vessel occlusion (mean +/- SD, 500 +/- 194 mL/min before and 457 +/- 219 mL/min after coagulation) because stroke volume slightly increased from 2.65 +/- 1.16 mL/beat to 3.1 +/- 1.5 mL/beat. The right to left CO ratio remained at 1.4. The UV flow/combined CO ratio decreased from 34 +/- 14% to 25 +/- 10% after vessel coagulation. The pulsatility index in the DV increased from 0.4 +/- 0.1 to 0.7 +/- 0.4. The DV blood flow volume remained relatively constant after the intervention. The DV shunting rate, given as DV/UV flow ratio, increased significantly from 30.8 +/- 4.7% to 59.3 +/- 25.0%.

CONCLUSIONS

The nearly simultaneous closure of arterial and venous umbilical vessels changed the flow pattern in the UA and significantly reduced placental blood perfusion. It did not distinctly change the blood flow volume rate through the DV, and consequently the DV shunting rate was increased. The combined CO was not significantly affected by the vascular obstruction, whereas the fraction of combined CO directed to the placenta was reduced.

[Ductus venosus Arantii in the fetal venosus circulation: anatomical and clinical aspects]

OBJECTIVE

The purpose of this study was to summarize the published data on the anatomical structure of the ductus venosus, the mechanism of regulation of the ductus venosus shunting and its role in the fetal survival and the possible use of the measurement of the ductus venosus shunting in the clinical practice.

DESIGN

Review.

SETTING

Department of Obstetrics and Gynecology Medical Faculty Charles University Hradec Králové.

METHODS

We summarized published data on the ductus venosus shunting in the fetal venosus circulation with the regulatory mechanisms, doppler ultrasound diagnostic methods and the medical importance.

CONCLUSION

The present review summarizes the results of clinical and experimental research on the ductus venosus in the fetal circulation.

Fetal celiac and splenic artery flow velocity and pulsatility index: longitudinal reference ranges and evidence for vasodilation at a low portocaval pressure gradient

OBJECTIVES

To establish longitudinal reference ranges for the fetal celiac and splenic arteries flow velocity and pulsatility index (PI), and to determine their hemodynamic relationship to venous liver perfusion and distribution and to other essential arteries.

METHODS

This was a prospective longitudinal study of 161 low-risk pregnancies. Doppler recordings of the celiac and splenic arteries were made on three to five occasions at 3-5-week intervals to establish reference ranges for blood velocity and PI measurements. Peak systolic velocity in the ductus venosus, a shunt between the umbilical and inferior caval veins, was used to represent the umbilicocaval (i.e. portocaval) pressure gradient, and the left portal vein blood velocity represented the umbilical distribution to the right liver lobe. The correlations between the celiac, splenic and hepatic arteries were determined, and their association with the middle cerebral and umbilical artery PIs (MCA-PI and UA-PI) was assessed.

RESULTS

Longitudinal reference ranges for the fetal celiac and splenic arteries were established based on 510 and 521 observations, respectively, during gestational weeks 21-39. Terms for calculating conditional reference ranges to be used for repeat observations are provided. Celiac and splenic artery PIs were low when portocaval pressure and umbilical supply to the right lobe were low (P < 0.0001). Their peak systolic velocity and PI were correlated (r = 0.7 (95% CI, 0.6-0.8) and r = 0.5 (95% CI, 0.3-0.6), respectively), while the PI of the hepatic artery correlated weakly with those of the celiac and splenic arteries. They were positively associated with the MCA-PI and UA-PI (P < 0.0001).

CONCLUSION

We provide longitudinal reference ranges for the fetal celiac and splenic arteries Doppler measurements and show that they are involved in maintaining portal liver perfusion independently from the hepatic artery.

Blood pressure estimation in the human fetal descending aorta

OBJECTIVES

The objectives of this study were to estimate fetal blood pressure non-invasively from two-dimensional color Doppler-derived aortic blood flow and diameter waveforms, and to compare the results with invasively derived human fetal blood pressures available from the literature.

METHODS

Aortic pressures were calculated from digitally recorded color Doppler cineloops of the fetal descending aorta by applying the Womersley model in combination with the two-element Windkessel model, assuming constant pulse wave velocity during the second half of pregnancy. The results were compared with invasively derived human fetal blood pressures obtained from the literature.

RESULTS

In 21 normal pregnancies the estimated mean aortic pressure regression line increased linearly from 28 mmHg at 20 weeks of gestation to 45 mmHg at 40 weeks of gestation. The pulse pressure based on the regression line increased linearly from 21 mmHg at 20 weeks of gestation to 29 mmHg at 40 weeks of gestation. The aortic compliance exhibited a log linear relationship with the gestational age and a statistically significant eightfold increase was observed between 20 and 40 weeks. The aortic downstream peripheral resistance exhibited an exponentially decaying relationship across the same gestational age range. Non-invasively derived aortic systolic and diastolic aortic pressures were comparable with previously reported invasively derived systolic and diastolic umbilical arterial pressures; however, the mean pressures differed significantly from those reported in the umbilical artery in a separate study. The aortic systolic pressures calculated in this study were significantly higher than invasively derived left ventricular systolic pressures that have been previously reported in the literature.

CONCLUSIONS

This study demonstrates the feasibility of estimating arterial blood pressure in the human fetus. The method described is of potential use in assessing fetal blood pressure non-invasively, particularly for studying relative changes with time.

Fetal responses to epidural analgesia as evidenced by Doppler indices

BACKGROUND

This study was designed to evaluate the maternal effects ofepidural analgesia by different local anesthetics and their impact on placental and fetal blood flow.

METHODS

Depending on the type of local anesthetics used, sixty full-term parturients were randomly allocated into 3 equal groups in a randomized blind study; Group (1) received Bupivacaine (0.125%), Group (2) received Ropivacaine (0.2%) and, Group (3) received Levobupivacaine (0.125%). Epidural fentanyl (100 microg) was added to all groups. Safety was assessed by recording the mothers' characters and vital signs as well as the fetal Doppler indices while efficacy was assessed by measuring severity of pain, onset and duration of analgesia, and the motor blockade. Doppler velocimetry studies for fetus included monitoring of Umbilical Artery Pulsitility Indices (UAPI) and Middle Cerebral Artery Pulsitility Indices (MCAPI).

RESULTS

Parturient in all groups were comparable. Pulse rate and arterial blood pressure were significantly decreased in all groups after analgesia, but remained within normal ranges. The pain score, had significant reduction in all groups with best results observed in Group 3. The onset of analgesia was relatively rapid in Group 2 followed by Group 3 then Group 1. The duration of analgesia was prolonged in Group 1 followed by Group 3 and then Group 2. There was no incidence of motor block except in 5 parturient (20%) in Group 1. UAPI was significantly decreased in the three studied groups after epidural analgesia. But, during uterine contraction, there was slight elevation in the UAPI in all groups. The best improvement in placental perfusion was observed in Group 3, then Group 1, and the least was Group 2. On the other hand, MCAPI was significantly increased in al groups after epidural analgesia. But, during uterine contraction, there was slight decrease in the MCAPI in the three groups. The best improvement in MCAPI was observed in Group 3, then Group 1, and the least was Group 2.

CONCLUSION

All local anesthetics produced excellent analgesia during labor. The Doppler indices were improved in the three groups with the best results in levobupivacaine group.

Human and software error in ductus venosus Doppler waveform analysis

Ductus venosus waveform analysis has become increasingly affected by technical errors; however, these errors could be avoided if more attention was paid during sampling and analysis. The most common misevaluations include incorrect tracing, under- or overestimation of the peak systolic velocity, overestimation of the end-diastolic velocity, and, as a consequence, incorrect calculation of the pulsatility index facilitated either by human or software error. This article proposes practical suggestions to avoid technical errors in ductus venosus waveform analysis.

Arterial supply and venous drainage of the choroid plexus of the human lateral ventricle in the prenatal period as revealed by vascular corrosion casts and SEM

The topography of the arterial supply and venous drainage was visualised by corrosion casting and scanning electron microscopy in the human foetal (20 weeks) choroid plexus of the lateral ventricle. Although secondary villi were not yet present at that developmental stage, the topography of the large arteries and veins almost fully corresponded to that described in adult individuals. The only major difference observed was a lack of the typical tortuosity of the lateral branch of the anterior choroidal artery and of the superior choroidal vein, which probably develops during further expansion of the vascular system associated with the formation of secondary villi.

Digital-image analysis of the left common carotid artery in human foetuses

The rate of growth of the left common carotid artery during gestation has not been sufficiently evaluated. The present study was performed on 128 spontaneously aborted human foetuses aged 15-34 weeks to compile normative data for the dimensions of the left common carotid artery at varying gestational ages. Using anatomical dissection, digital image analysis (system of Leica Q Win Pro 16) and statistical analysis (ANOVA, regression analysis), a range of measurements (length, original external diameter and volume) for the left common carotid artery during gestation was examined. No significant gender differences were found (p > 0.05). The growth curves of the best fit for the plot of each morphometric parameter against gestational age were generated. The lengths ranged from 14.82 +/- 2.22 to 42.84 +/- 4.32 mm, according to the linear model y = -9.6918 + 1.5963 x +/- 3.1706 (r = 0.95; p < 0.001). The original external diameter increased from 0.72 +/- 0.18 to 3.28 +/- 0.40 mm, according to the linear function y = -1.5228 + 0.1428 x +/- 0.2749 (r = 0.95; p < 0.001). The left common carotid artery-to-aortic root diameter ratio increased from 0.356 +/- 0.062 to 0.480 +/- 0.101. The left common carotid artery-to-aortic arch diameter ratio increased from 0.447 +/- 0.079 to 0.535 +/- +/- 0.113. The volume ranged from 6.73 +/- 4.06 to 369.30 +/- 107.42 mm3 in accordance with the quadratic function y = 344.8 - 41.001 x + 1.254 x2 +/- +/- 46.955 (R2 = 0.87). The parameters examined have clinical application in the early recognition of arterial abnormalities, especially aortic coarctation.

Fetal ductus venosus pulsatility index and diameter during 20-30 weeks gestation

OBJECTIVE

To present normal range of the pulsatility index and the smallest diameter in the ductus venosus in normal fetuses throughout gestation.

MATERIAL AND METHOD

This was a prospectively cross-sectional study. Three measurements were made for the ductus venosus diameter and the pulsatility index in each fetus during fetal quiescence. Statistical Package for the Social Sciences 14.0 software was used to create nomograms for the ductus venosus pulsatility index and diameter against gestational age. Four hundred and sixty normal fetuses aged seventeenth to thirty-seventh weeks were evaluated.

RESULTS

The median diameter of the ductus venosus was linear across gestation.

CONCLUSION

The nomograms for the ductus venosus pulsatility index and diameter are presented. The size of the narrowest portion of the DV grows in a linear relationship through gestation.

The periphery of the human fetal adrenal gland is a site of angiogenesis: zonal differential expression and regulation of angiogenic factors

CONTEXT

Although the inner fetal zone (FZ) of the mid-gestation human fetal adrenal (HFA) produces dehydroepiandrosterone sulfate, the function of the outer definitive zone (DZ) remains less clear. We have proposed that the DZ phenotype is that of a pool of progenitor cells, many of which are mitotically active. Recently, we studied HFA expression of a family of vascular endothelial cell-specific angiogenic factors, the angiopoietins (Angs), and demonstrated that Ang2 was localized predominantly in the periphery of the gland. Ang1 stabilizes, whereas Ang2 destabilizes, vessels, increasing responsiveness to angiogenic stimuli such as vascular endothelial growth factor (VEGF)-A and fibroblast growth factor (FGF)-2.

OBJECTIVE

Our objective was to test the hypothesis that the periphery of the HFA is a site of angiogenesis.

DESIGN

Studies were conducted involving RNA, frozen sections, and primary cell cultures from midgestation HFAs.

MAIN OUTCOME MEASURES

Immunofluorescence, laser capture microdissection, and real-time quantitative RT-PCR were used.

RESULTS

Double immunostaining demonstrated that proliferating endothelial cells were limited to the DZ and DZ/FZ border. Ang2 mRNA was primarily expressed in the DZ, whereas Ang1 mRNA was primarily in the FZ. VEGF-A and FGF-2 mRNA levels were higher in the DZ. FGF-2 (10 ng/ml) induced Ang2 mRNA by 4-fold in both zones of cells (P < 0.01, at 24 h), but not Ang1 or VEGF-A mRNA.

CONCLUSION

Data suggest that angiogenesis occurs at the periphery of the HFA. The DZ-predominant expression of Ang2 may be explained, in part, by the parallel pattern of FGF-2 expression.

Enhanced placental cholesterol efflux by fetal HDL in Smith-Lemli-Opitz syndrome

Previous studies from this laboratory have shown that maternal-derived cholesterol can be effluxed from trophoblasts to fetal HDL and plasma. We had the opportunity to study for the first time the ability of HDL and plasma from a fetus with the Smith-Lemli-Opitz syndrome (SLOS) to efflux cholesterol from trophoblasts. It was unclear whether cholesterol could be effluxed to fetuses with SLOS since lipoprotein levels are often very low. To answer this question, cord blood was collected from the placentas of an SLOS fetus and unaffected fetuses just after delivery. Plasma cholesterol concentrations were very low in the affected fetus; cholesterol, 7-dehydrocholesterol, and 8-dehydocholesterol concentrations were 14.1, 4.5, and 5.2 mg/dl, respectively. The HDL from the fetal SLOS effluxed approximately 50% more cholesterol from a trophoblast cell line, were smaller in size, and had a lower cholesterol to phospholipid ratio as compared to HDL from unaffected fetuses or adults. Plasma from the SLOS fetus effluxed cholesterol to a similar percentage as unaffected fetal plasma or adult plasma, possibly due to fewer HDL particles as demonstrated in previous SLOS patients. These novel data demonstrate that the cholesterol-deficient SLOS fetus is able to obtain cholesterol from trophoblasts at a time when cholesterol is playing a critical role in development, and has implications for design of treatments for cholesterol deficiency syndromes as well as understanding of prenatal cholesterol transport in humans.

Echo-Doppler ultrasonographic assessment of resistance and velocity of blood flow in the ductus venosus throughout gestation in fetal lambs

It has been postulated that during fetal hypoxia, the blood flow shunted through the ductus venosus increases and may account for upto 70% of the total umbilical flow. The objectives of the present study were to use ultrasonography to determine the velocities and waveform indices of blood flow in the ductus venosus in the fetal lamb. The ductus venosus of 15 lamb fetuses was evaluated weekly from Days 45 to 143 of gestation (Day 0=day of AI). The Doppler indices measured were: S/D, the systole/diastole ratio; RI, the resistance index; and PI, the pulsatility index. The velocity waveforms studied were: SV, the peak velocity during ventricular systole; D, the peak velocity during ventricular diastole; aV, the lowest forward velocity during atrial contraction; and TAMV, the time-averaged maximum velocity. Doppler indices from Days 52 to 143 were highly correlated: S/D versus PI (r=0.96, P<0.0001), and versus RI (r=0.93, P<0.0001); and PI versus RI (r=0.97, P<0.0001). Velocity indices were also positively correlated: velocity SV versus D (r=0.87, P<0.0001), versus aV (r=0.79, P<0.05), and versus TAMV (r=0.98, P<0.0001); D versus aV (r=0.88, P<0.05), and versus TAMV (r=0.87, P<0.05); and aV versus TAMV (r=0.82, P<0.05). Doppler indices were negatively correlated with SV (r=-0.22, P<0.03); D (r=-0.37, P<0.0001); TAMV (r=-0.32, P<0.05) and with aV (r=-0.67, P<0.05). The mean value of each Doppler index decreased 40% from Days 52 to 73 (e.g., PI from 0.82+/-0.08 to 0.51+/-0.10; P<0.05), with no significant changes thereafter. Mean (+/-S.E.M.) values of velocity indices SV, D, aV, and TAMV rose twofold from Days 60 to 115 of gestation (e.g., SV from 54.4+/-8.8cm/s to 104.9+/-19.7 and aV from 24.8+/-6.9 to 54.9+/-5.9; P<0.05). In conclusion, Doppler ultrasonography facilitated assessment of the blood flow pattern in the ductus venosus in lamb fetuses between Days 52 and 143.

Color M-mode propagation velocity, but not its ratio to early diastolic inflow velocity, changes throughout gestation in normal human fetuses

OBJECTIVES

Color M-mode propagation velocity (Vp) is a measure of diastolic function in adults and, when combined with early diastolic inflow velocity (E), the ratio E/Vp reflects ventricular filling pressure. Early detection of diastolic compromise may benefit fetal patients at risk for developing heart failure. The objectives of this study were to measure values for Vp and inflow peak E in a group of normal fetuses, to analyze age-dependent alterations in these measurements, and to evaluate the interobserver and intraobserver variability of the measurements.

METHODS

Thirty-two normal fetuses at between 20 and 35 weeks' gestation underwent echocardiography. Color M-mode Vp was measured from the four-chamber view for the right (RV) and left (LV) ventricles, and mitral and tricuspid inflow velocities were determined by pulsed-wave Doppler ultrasound. The values obtained were compared with previously reported findings in adults.

RESULTS

Adequate tracings were obtainable in 23 patients for the RV and 29 for the LV. Mean Vp values for the RV (15.3 +/- 3.2 cm/s) and LV (20.8 +/- 5.6 cm/s) were lower than normal adult values, and Vp values were significantly lower for the RV than the LV (P < 0.001). Applying Bazett's heart rate correction, values for RV (23.4 +/- 4.8 cm/s) and LV (31.9 +/- 8.7 cm/s) remained lower than normal adult values. There was a linear correlation of Vp with gestational age for the RV (R = 0.69, P < 0.001), and the ratio of E/Vp corrected for heart rate for the RV (1.51 +/- 0.26) remained constant throughout gestation. Interobserver bias was high but intraobserver bias low, at 19 and 1.1%, respectively.

CONCLUSIONS

Vp is lower in fetal than in adult life. Vp for the RV changes in a manner indicative of improving diastolic function throughout normal gestation, providing insight into the alterations in diastolic function with gestation that contribute to increases in cardiac output. The use of Vp to assess diastolic function disturbance in fetuses is feasible, but high interobserver variability is problematic.

Neurosteroids in the fetus and neonate: Potential protective role in compromised pregnancies

Complications during pregnancy and birth asphyxia lead to brain injury, with devastating consequences for the neonate. In this paper we present evidence that the steroid environment during pregnancy and at birth aids in protecting the fetus and neonate from asphyxia-induced injury. Earlier studies show that the placental progesterone production has a role in the synthesis and release of neuroactive steroids or their precursors into the fetal circulation. Placental precursor support leads to remarkably high concentrations of allopregnanolone in the fetal brain and to a dramatic decline with the loss of the placenta at birth. These elevated concentrations influence the distinct behavioral states displayed by the late gestation fetus and exert a suppressive effect that maintains sleep-like behavioral states that are present for much of fetal life. This suppression reduces CNS excitability and suppresses excitotoxicity. With the availability of adequate precursors, mechanisms within the fetal brain ultimately control neurosteroid levels. These mechanisms respond to episodes of acute hypoxia by increasing expression of 5alpha-reductase and P450scc enzymes and allopregnanolone synthesis in the brain. This allopregnanolone response, and potentially that of other neurosteroids including 5alpha-tetrahydrodeoxycorticosterone (TH-DOC), reduces hippocampal cell death following acute asphyxia and suggests that stimulation of neurosteroid production may protect the fetal brain. Importantly, inhibition of neurosteroid synthesis in the fetal brain increases the basal cell death suggesting a role in controlling developmental processes late in gestation. Synthesis of neurosteroid precursors in the fetal adrenal such as deoxycorticosterone (DOC), and their conversion to active neurosteroids in the fetal brain may also have a role in neuroprotection. This suggests that the adrenal glands provide precursor DOC for neurosteroid synthesis after birth and this may lead to a switch from allopregnanolone alone to neuroprotection mediated by allopregnanolone and TH-DOC.