Variation in the amniotic fluid index following moderate physical activity in water during pregnancy

BACKGROUND

To evaluate changes in the amniotic fluid index (AFI) in low-risk pregnant women before and after physical activity in water.

METHODS

This was a prospective trial with a before-after approach. Women carried out moderate physical activity for 50 min, 3 times a week, while partially immersed in a swimming pool at 30 degrees C. Women with 2 or more previous cesarean sections, with a high-risk pregnancy or medical contra-indications for physical activity were excluded. They were evaluated weekly by ultrasonography, from 20 weeks of pregnancy until delivery, to evaluate AFI before and after physical activity in water. A second observer also performed the AFI measurements, in order to establish inter-observer variability. Analysis was performed using Student's t-test or Wilcoxon tests. The linear correlation coefficient was used to assess inter-observer variability.

RESULTS

A total of 25 pregnant women, 19-36 years of age, participated in the study between May 2003 and December 2004. A total of 232 ultrasonographic evaluations of AFI were carried out, a mean of 9.28 examinations per woman. Statistically significant increases in AFI were found following immersion at almost every week of pregnancy. The increase in AFI post-immersion compared to pre-immersion values ranged from 8.8 to 21.5%. There was good inter-observer agreement. The correlation coefficient for the inter-observer variability was 0.78 for pre-immersion measurements, and 0.70 for post-immersion measurements.

CONCLUSIONS

Physical activity in water appears to significantly increase AFI. Since this is a non-invasive therapy, we speculate that its clinical application may have significant value.

Transcervical intrapartum amnioinfusion for preterm premature rupture of the membranes

OBJECTIVES

To investigate the effect of transcervical amnioinfusion on the management of labour and neonatal outcomes in preterm premature rupture of the membranes.

STUDY DESIGN

This clinical trial included 86 patients with premature rupture of the membranes between weeks 27 and 35 of gestation. Patients were randomly assigned to receive amnioinfusion via a two-way catheter or to the control group. Clinical management was otherwise the same in both groups.

RESULTS

Amnioinfusion decreased the frequency of variable decelerations in fetal heart rate (27.9% versus 53.5%, p<0.05) and the rate of obstetric interventions motivated by nonreassuring fetal status (13.6% versus 52.4%, p<0.05). At delivery, pH values were significantly higher in the treatment group than in the conventionally managed control group (median 7.29 versus 7.27).

CONCLUSIONS

Intrapartum transcervical amnioinfusion for preterm premature rupture of the membranes reduced the number of interventions needed because of nonreassuring fetal status, and improved neonatal gasometric values without increasing maternal or fetal morbidity.

Abnormal Doppler velocimetry is related to adverse perinatal outcome for borderline amniotic fluid index during third trimester

AIM

To evaluate the relationship between abnormal Doppler velocimetry and adverse perinatal outcomes in pregnancies with borderline amniotic fluid index (AFI).

METHODS

Medical records of 3740 pregnancies with known AFI and Doppler velocimetry measurements within 2 weeks of delivery, and delivered between January 1996 and December 2003, were retrospectively analyzed. Borderline AFI was defined as 5 cm < AFI < or = 8 cm. For the umbilical artery, Doppler velocimetry was considered abnormal when the S/D ratio was greater than 3.0 or when end-diastolic flow was absent; whereas, for the uterine artery, the S/D ratio was greater than 2.6 or presence of end-systolic notch was defined as abnormal. Adverse perinatal outcomes (small for gestational age, cesarean section for fetal distress, 5 min Apgar score of less than 7, respiratory distress syndrome, NICU admission, and perinatal death) according to Doppler velocimetry in borderline AFI were evaluated.

RESULTS

Compared to the normal AFI group (n = 3523), the borderline AFI group (n = 217) had significantly higher incidence of adverse perinatal outcome (28.8% vs 54.8%). There was 3-fold increase in the incidence of adverse perinatal outcome among women with the borderline AFI in comparison to normal AFI (OR, 3.00; CI, 2.27-4.00). When abnormal Doppler velocimetry was associated with borderline AFI, a 5-fold increase in the incidence of adverse perinatal outcome was noted (OR, 5.26; CI, 3.00-9.21).

CONCLUSION

In the borderline AFI group, the presence of abnormal Doppler velocimetry measurement was related to increased risk of adverse perinatal outcome. Thus, borderline AFI of 5-8 cm, especially when associated with abnormal Doppler velocimetry, mandates closer antenatal surveillance.

Curve of amniotic fluid index measurements in low-risk pregnancy

OBJECTIVES

To establish a curve of amniotic fluid index [AFI] measurements from the 20th to the 42nd week of pregnancy.

METHODS

A prospective and descriptive study was performed, in which an independent sample of 2,868 low-risk pregnant women were studied using routine ultrasound, including fetal biometry and measurement of AFI. Data were analysed using multiple linear regression, and constructing a curve using 2.5th, 10th, 50th, 90th and 97.5th percentiles of the AFI measurements, according to gestational age, and after submitting values to smoothing process using quadratic polynomial adjustment.

RESULTS

There was a significant variation in AFI measurements at the different gestational ages. The 50th percentile remained practically constant at approximately 150 mm between the 20th and 33rd week, after which there was a decline in volume, which became evident after the 38th week. At the 40th week, the 10th percentile was around 62 mm and the 2.5th percentile around 33 mm.

CONCLUSIONS

The curve of percentiles of AFI measurements in low-risk pregnant women showed significant decrease with gestational age, especially after the 33rd week. These data should be validated for a diagnosis of increased or decreased volumes of amniotic fluid at specific gestational ages.

Comparison of fern and evaporation tests for detection of ruptured fetal membranes

Timely diagnosis of ruptured fetal membranes during the pregnancy is important. This study in the Islamic Republic of Iran compared the sensitivity and specificity of the evaporation test that requires no special equipment with the standard fern test requiring a microscope. Two groups of 50 pregnant women were studied: 1 with artificially ruptured membranes (gold standard) and 1 with intact membranes. The positive and negative predictive values of the fern test were 92% and 96% and for the evaporation test were 89% and 98%. The evaporation test is a simple, easy and non-expensive diagnostic test for ruptured membranes.

Clinical features of polyhydramnios associated with fetal anomalies

The purpose of this study was to examine the clinical features of pregnancy complicated by polyhydramnios associated with fetal anomalies. Sixty-nine patients with a singleton pregnancy complicated by polyhydramnios were retrospectively analyzed. Based on prenatal ultrasonographic findings, 13 cases were considered to have idiopathic polyhydramnios and the remaining 56 cases were associated with fetal anomalies. Between these two groups, no significant difference was found in the gestational weeks when polyhydramnios developed. However, significant difference was noted in the maximum amniotic fluid index (AFI) values during the pregnancy period; 25.4 +/- 2.7 cm in the former, and 30.6 +/- 8.9 cm in the latter (P = 0.0004). In all of 13 cases with idiopathic polyhydramnios, AFI values remained less than 30 cm until delivery. Twenty-two patients (39%) with fetal anomalies required a prenatal treatment such as amnioreduction and tocolysis, whereas only one patient (7.7%) with idiopathic polyhydramnios needed tocolysis therapy (P = 0.03). There was a significant risk of premature delivery with fetal anomalies (35.6 +/- 3.9 weeks' gestation vs. 38.8 +/- 1.5 weeks' gestation, P = 0.004) because of refractory polyhydramnios, rupture of membranes, non-reassuring fetal status, and intrauterine fetal death, and although most infants with idiopathic polyhydramnios were appropriate-for-dates, many of the infants with congenital anomalies were small-for-dates. Significant risk of fetal anomalies should be considered in pregnant women with severe polyhydramnios (AFI > or = 30 cm), an increased trend of amniotic fluid during the pregnancy period, polyhydramnios requiring a prenatal treatment, or fetal growth restriction. On the other hand, based on our experience, a fetus without these conditions seems to have a low risk of congenital anomalies even if polyhydramnios is noted.

Effect of esophageal ligation on small intestinal development in normal and growth-retarded fetal rabbits

OBJECTIVE

The uninterrupted passage of amniotic fluid through the gastrointestinal tract is hypothesized to influence both intestinal and overall fetal somatic development. The effect of in utero esophageal ligation (EL) and therefore the exclusion of AF on somatic growth, small intestinal (SI) morphology and proliferation, and the expression of the glucose transporter sodium-glucose cotransporter 1 (SGLT-1) in both normal and intrauterine growth-retarded (IUGR) fetal rabbits were evaluated.

METHODS

Thirteen pregnant New Zealand white rabbits underwent surgery on day 24 of their normal 31-day gestation. Ipsilateral normal and IUGR fetuses underwent EL; the contralateral normal and IUGR fetuses underwent cervical exploration only forming 4 study groups (control-normal, control-IUGR, EL-normal and EL-IUGR). Rabbits were killed on day 31. Small intestinal villus height was measured, and epithelial cell proliferation was deter mined by proliferating cell nuclear antigen staining. Sodium-glucose cotransporter 1 messenger RNA (mRNA) and protein expressions were analyzed. Statistical analysis was performed using 2-way analysis of variance.

RESULTS

Esophageal ligation reduced fetal weight in IUGR by 15% and in normal by 10%. Villus height was significantly reduced in IUGR versus normal in both control and EL (control, P = 0.01; EL, P = 0.05). Intrauterine growth-retarded fetuses had reduced SI proliferation versus normal in both control and EL. Sodium-glucose cotransporter 1 mRNA production in EL fetuses was equal to control fetuses. Esophageal ligation-normal and EL-IUGR fetuses exhibited reduced protein levels and decreased staining for SGLT-1 in villus enterocytes.

CONCLUSIONS

Amniotic fluid exclusion by in utero EL reduced fetal weight. Small intestinal proliferation was not affected by EL. Although SGLT-1 mRNA and protein were produced in all 4 groups, exposure of the fetal gastrointestinal tract to amniotic fluid appears necessary for proper brush border expression of nutrient transporter proteins.

[Role of amniodrainage and color Doppler in the management of the twin-to-twin fetal blood transfusion syndrome]

The purpose of this study was to evaluate our experience with twin-to-twin transfusion syndrome (TTTS) and to determine the effectiveness in treating TTTS with amniodrainage and use of color Doppler. 31 out of 45 pregnant women were diagnosed with TTTS. The average gestational age at time of diagnosis was 20 weeks (range 16w to 33 w). During the course of treatment we have performed 29 standard and 20 aggressive amnioreduction procedures and 3 procedures of septostomy. Color Doppler studies of fetal-maternal vessels (a. and v. umbilical, middle cerebral artery, ductus venosus, a. renalis, a. uterine) were done in all cases before and after procedures. The average number of amniocentesis performed per patient was 3 (range 1 to 7). The average total volume of amniotic fluid removed per patient over the course of the pregnancy was 3.2 L (range 500 to 8000 ml). In 22 (70.9%) cases pregnancy was prolonged to 4-15 weeks. After amnioreduction the indexes of umbilical and uterine blood flow were improved and were depended on the level of polygydramnion revealing decrease of resistance. The risk of perinatal death was associated with an absent or reversed end-diastolic blood flow in the donor umbilical artery and with a pulsatile umbilical vein or absent or reversed end-diastolic flow in the ductus venosus of the recipient. The renal artery PI in recipient was lower than in donor (p<0.01). In cases with septostomy we found an elevation of the donor's urine bladder, probably as a consequence of a diminished level of hypovolemia and this resulted in an improvement of the renal function. 67.7% of the treated fetuses survived. Neonatal morbidity was 23.8% among the survivors. Average gestational age of delivery was 32 weeks (range 20-37 w). These findings may play a significant role in consulting parents in presence of TTTS and in selecting the appropriate treatment strategy in regards to the perinatal outcome.

Lymphodynamics in the fetus and newborn

Body fluid is distributed among three major fluid spaces: plasma, interstitial fluid, and intracellular fluid. The distribution of fluid in each of these compartments is dramatically different in the fetus and newborn compared to the adult. In addition, the amniotic fluid that surrounds the fetus may also be considered an extension of the extracellular space of the fetus. The purpose of this review is to discuss the complex mechanism that regulates volume in the fetus and newborn as well as the regulation of fluid distribution between the plasma and interstitial fluid, while placing special emphasis on the role the lymphatic system plays in mediating and maintaining this distribution.

Rapid detection of trisomy 21 by gene dosage analysis using quantitative real-time polymerase chain reaction

AIM

Rapid detection of fetal aneuploidy helps inform a mother's choice about the course of her pregnancy. Obtaining results by fluorescent in situ hybridization (FISH) requires more than 24 h, and thus a more rapid method is needed.

METHODS

Conventional G-banding and FISH for chromosome 21 were performed for cultured amniocytes. Genomic DNA was extracted from uncultured amniocytes obtained from 23 patients. TaqMan polymerase chain reaction (PCR) primers were designed to amplify the potassium voltage gated channel gene on chromosome 21q22.12 and the ribosomal phosphoprotein gene on 18q21.1. Quantitative real-time PCR was performed for these two gene fragments and the differences of the threshold cycle (Ct) of the two genes (Ct 18-Ct 21) were calculated for each sample.

RESULTS

G-banding revealed that 19 patients had a normal karyotype and four had trisomy 21. FISH resulted in one case of a false positive. The Delta Ct values (Ct 18-Ct 21) of trisomy 21 patients were significantly higher than the values of individuals with normal karyotypes (P < 0.001) and there was no overlapping.

CONCLUSIONS

Fetal trisomy 21 is rapidly detectable by gene dosage analysis from amniocytes using quantitative real-time PCR.

Reduction of aquaporin-8 on fetal membranes under oligohydramnios in mice lacking prostaglandin F2α receptor

AIM

To investigate the association between aquaporin-8 (AQP-8: a water channel protein) expression in fetal membranes and oligohydramnios during near-term and postdate pregnancy, we set up an oligohydramnios model using prostaglandin F2 alpha receptor (FP)-deficient mice.

METHODS

Pregnant FP-deficient mice from 14 to 21 gestational days (GD) were killed to measure the amniotic fluid volume (AFV), and fetal membranes were collected for the analysis of aquaporin-8 expression.

RESULTS

The AFV was highest at 14 GD, and was significantly decreased to 28% and 0% at 20 GD and 21 GD, respectively, compared with the volume at 14 GD. Immunohistochemistry and immunoblot analysis showed that aquaporin-8 was expressed in the basal component of fetal membranes, and that the protein level was significantly decreased to 60% at 20 GD compared with that at 14 GD.

CONCLUSIONS

We demonstrated that AQP-8 expression in the fetal membrane was decreased at post term in FP-deficient mice. Our findings suggest that aquaporin-8 in fetal membranes may be involved in the regulation of AFV, especially when oligohydramnios occurs.

Use of topical human amniotic fluid in the treatment of acute ocular alkali injuries in mice

PURPOSE

To evaluate the efficacy of topical human amniotic fluid (HAF) in the treatment of ocular acute alkali burns in mice.

DESIGN

Experimental study.

METHODS

A chemical burn with 2 microl of sodium hydroxide 0.15 mol/l was created in one eye of 30 mice. The animals were divided into gender- and age-matched groups according to the topical treatment that was administered: group 1 was treated with preterm HAF (n = 10 mice); group 2 was treated with term HAF (n = 10 mice), and group 3 was treated with saline solution (n = 10 mice). Treatment consisted of one drop that was applied to the burned eye five times per day (week one), and three times per day (week two). The epithelial defect was photographed and measured on days two and four. Ocular burn damage was assessed at days two, seven, and 14 after a pre-established classification. On day 14, both eyes of each mouse were enucleated and assessed histopathologically.

RESULTS

Median epithelial defect (interquartile range [IQR], 25th, 75th percentile) at day four was 9.93% (IQR, 8.57, 11.27) for group 1, 7.30% (IQR, 5.96, 8.97) for group 2, and 18.92% (IQR, 11.71, 27.64) for group 3 (P < .0076). The overall change (difference in slope) in ocular burn score between days 2 and 14 was -0.127 (P = .009) in group 1 vs 3, -0.134 (P = .012) in group 2 vs 3, and 0.007 (P = .88) in group 1 vs 2. On histologic examination saline solution-treated corneas had more inflammatory cells and blood vessels than HAF-treated corneas.

CONCLUSION

Topical preterm/term HAF was an effective topical therapy for limiting the damage after acute alkali burns of the eye in this animal model.

Stable expression of a neuronal dopaminergic progenitor phenotype in cell lines derived from human amniotic fluid cells

Cells from human amniotic fluid derived from the fetus are considered a source of multipotent cells. Their properties have not been fully exploited, partially because unlike other embryonic sources such as embryonic stem (ES) cells, cell lines from amniocentesis samples have not been generated. We have established and characterized the properties of eight individual cell lines. Flow cytometry using several cell surface markers showed that all cell lines generated consisted of homogeneous populations that lack HLAII antigenicity. Using a combination of immunocytochemistry, Western blotting, and RT-PCR, we found weak expression of Oct4 and nestin and strong expression of tubulin-betaIII, MAP2, and tau. Specific markers for cholinergic, (nor)adrenergic, and GABAergic neurons or glia were weakly expressed or absent, whereas expression of factors implicated in early induction of dopaminergic neurons, TGF-beta3 and beta-catenin were present. Further analysis showed strong expression of EN-1, c-RET, PTX3, and NURR1 essential for induction and survival of midbrain dopaminergic neurons, TH, AADC, and VMAT2 components of dopamine synthesis and secretion, and syntaxin1A and SNAP-25 necessary for neurotransmitter exocytosis. This phenotype was retained throughout passages and up to the current passage 36. Expression of neuronal and dopaminergic markers in individual AF cell lines was comparable to expression in neurons induced from ES cells and in IMR-32 and SH-SY5Y neuroblastomas. Our data show that cell lines can be derived from subcultures of amniocentesis, and are primarily composed of a population of progenitors with a phenotype similar to that of committed mesencephalic dopaminergic neurons.

Function of aquaporins in female and male reproductive systems

The flow of water and some other small molecules across cell membranes is important in many of the processes underlying reproduction. The fluid movement is strongly associated with the presence of aquaporins (AQPs) in the female and male reproductive systems. It has been suggested that AQPs mediate water movement into the antral follicle and play important roles in follicle development. AQPs are known to be involved in the early stage of spermatogenesis, in the secretion of tubule liquid and in the concentration and storage of spermatozoa. Fluid reabsorption in some regions of the male reproductive tract is under steroid hormone control and could be mediated by various AQPs. Also AQPs take part in the processes of fertilization, blastocyst formation (as the pathway for transtrophoectodermal water movement during cavitation) and implantation. Alterations in the expression and function or regulation of AQPs have already been demonstrated in disorders of the male reproductive system, such as abnormal sperm motility, the abnormal epididymis and infertility seen in cystic fibrosis, and varicocele. This article extensively reviews the distribution of AQPs in mammalian reproductive tissues and discusses their possible physiological and pathophysiological roles.

Amniotic fluid volume at 41 weeks and infant outcome

OBJECTIVE

To assess the usefulness of amniotic fluid index (AFI) in the assessment of postdate pregnancies.

STUDY DESIGN

A prospective, observational study was carried out on the AFI of 118 well-dated postdate pregnancies at 41 weeks within 2 days of delivery. The AFI quartile distribution was determined and correlated with the risk of thick meconium-stained liquor (MSL), intervention for fetal distress and admission to the special care baby unit (SCBU).

RESULTS

The median AFI was 8 cm, with a range from 1-33 cm. There was a significant inverse correlation between the occurrence of thick MSL, intervention for fetal distress and SCBU admission. Logistic regression analysis, upon adjusting for possible confounding factors, showed that only AFI in the 2 lower quartiles combined (< or = 8 cm) had a significant association with the risk of thick MSL (adjusted OR 11.0, 95th CI 2.43-49.8) but not admission to the SCBU. AFI in the lowest quartile (< or = 5 cm) had a significant association with the risk of intervention for fetal distress only (adjusted OR 7.95, 95th CI 1.67-37.7).

CONCLUSION

Although AFI may be used to predict the occurrence of thick MSL and the need for intervention for fetal distress in postdate pregnancies, its role on its own is limited.

Amniotic fluid volume and composition in mouse pregnancy

OBJECTIVE

The current study was undertaken to determine simultaneous changes in amniotic fluid (AF) volume and composition across gestation in the pregnant mouse.

METHODS

Young adult mice (6 to 7 weeks old) of the CB6F1 strain were mated overnight. AF was collected on consecutive days from embryonic days 9.5 through 18.5 for measurements of volume and composition. Statistical analysis included one-factor analysis of variance (ANOVA).

RESULTS

AF volume increased from 18 +/- 4 (SE) microL on day 9.5 to a maximum of 147 +/- 4 microL on days 15.5 to 16.5 and decreased sharply to 17 +/- 3 microL on day 18.5. AF osmolality was unchanged except for a rise prior to delivery on day 19.5 to 20.5. AF sodium, calcium, and glucose concentrations increased and subsequently decreased as gestation progressed. AF potassium, chloride, and lactate concentrations initially decreased and then increased across gestation. Prior to day 9.5 and after day 18.5, AF volume was too small for volume or compositional determinations.

CONCLUSIONS

In the mouse, the rise in AF volume from mid gestation to a maximum late in gestation is similar to that in humans while the sharp fall prior to delivery is not. As observed in the fetal sheep, the changes in fluid volume are associated with AF osmolality and solute concentration changes that are correlated with advancing gestational age. These observations together with the feasibility of quantifying AF volume and composition in the mouse fetus demonstrate the possibility of using genetically altered mice as a model for future studies on the molecular mechanisms underlying the regulation of AF volume and composition.

Comparison of the acoustic streaming in amniotic fluid and water in medical ultrasonic beams

AIM

Acoustic streaming in amniotic fluid has been investigated under a variety of conditions relevant to the diagnostic use of ultrasound.

METHOD

An ultrasonic Doppler method has been used for measurement. Streaming velocities have been compared with those generated in water for the same exposure conditions. Beams were generated by laboratory equipment simulating beams from clinical systems. The fluids were insonated IN VITRO using 3.5 MHz, 5 MHz and 7.5 MHz transducers in continuous wave (CW) and pulsed mode.

RESULTS

Acoustic streaming was measured in both amniotic fluid and water at the power levels 50 mW and 140 mW. Enhancement of velocities due to non-linear effects in high amplitude pulses was demonstrated for amniotic fluid as well as for water. The potential and limitations of present numeric methods for the prediction of acoustic streaming were explored.

CONCLUSION

Pulsed ultrasound caused similar streaming velocities in amniotic fluid and water while continuous wave beams induced significantly faster streaming in amniotic fluid than in water.

Fetal testosterone and empathy

BACKGROUND

In animals, fetal testosterone (fT) plays a central role in organizing the brain and in later social behavior. In humans, exposure to atypical levels of prenatal androgens may result in masculine behavior and ability patterns. Normal inter-individual variation in fT levels has also been correlated with later sex-typed behavior.

METHODS

In the current study, 38 children (24 male, 14 female), whose fT was analyzed in amniotic fluid, were followed up at age 4. They were asked to describe cartoons with 2 moving triangles whose interactions with each other suggested social relationships and psychological motivations.

RESULTS

Females used more mental and affective state terms to describe the cartoons than males. fT was not associated with the frequency of mental or affective state terms. Females also used more intentional propositions than males. fT was negatively correlated with the frequency of intentional propositions, taking sex differences into account. fT was also negatively correlated with the frequency of intentional propositions when males were examined separately. Males used more neutral propositions than females. fT was directly correlated with the frequency of neutral propositions, taking sex differences into account. This relationship was not seen when males and females were examined separately.

CONCLUSIONS

These findings implicate fT in human social development. The relevance of our findings to the 'extreme male brain' theory of autism is also discussed.

Induction of labor and perinatal outcome: the impact of the amniotic fluid index

OBJECTIVE

The purpose was to determine the impact of the amniotic fluid index on the perinatal outcome of patients admitted for induction of labor at term.

STUDY DESIGN

Patients (n=180) included in the study were those admitted for induction of labor at 37-42 weeks' gestation, with unfavorable cervix and intact membranes. The amniotic fluid index (AFI) was determined in all patients using the four-quadrant technique within 24 h of the induction of labor. Patients were divided into two groups based on their AFI: the oligohydramnios group with AFI < or = 5 cm (n = 66) and a normal group with AFI > 5 cm (n = 114). The perinatal outcomes of the two groups were compared.

RESULTS

The two groups were similar with regard to maternal age, gestational age, and birth weight. Meconium staining of the amniotic fluid was significantly higher in the group with AFI < or = 5 cm (p = 0.040). The number of cesarean deliveries due to fetal distress was significantly higher even after adjusting for other confounding factors in the group with AFI < or = 5 cm (adjusted OR 6.52 [95% CI 1.82, 23.2]; p < or = 0.0001). There was no significant difference between the two groups with regard to Apgar scores or neonatal admission.

CONCLUSION

Induction of labor at term in patients with oligohydramnios is associated with an increased risk of cesarean delivery due to fetal distress.

The association of cardiovascular responses with brain c-fos expression after central carbachol in the near-term ovine fetus

Central cholinergic mechanisms play important roles in the control of cardiovascular responses. However, in utero development of brain cholinergic mechanism in regulation of arterial pressure before birth is largely unknown. This study investigated cardiovascular responses to central application of carbachol in fetuses and determined functional development of the central cholinergic systems controlling fetal pressor responses in utero. Chronically prepared near-term ovine fetuses (90% gestation) received an injection of carbachol intracerebroventricularly (i.c.v.). Fetal cardiovascular responses were measured, and the brains were used for c-fos mapping studies. In response to carbachol injection i.c.v., fetal systolic, diastolic, and mean arterial pressure (MAP) immediately increased, accompanied by a bradycardia. The maximum increase of MAP was at 30 min after the i.c.v. injection of carbachol and lasted 90 min. Associated with the pressor response, the neuronal activity marked with c-fos was enhanced significantly in the fetal anterior third ventricle (AV3V) region (including the median preoptic nucleus and organum vasculosum of the lamina terminalis) in the forebrain, and in the area postrema, lateral parabrachial nucleus, nucleus tractus solitary, and rostral ventrolateral medulla in the hindbrain. These results indicate that the central cholinergic mechanism is functional in the control of fetal blood pressure at the last third of gestation, and the central AV3V region and hindbrain have been intact relatively during in utero development in sheep at 90% gestational stage.

Aminiotic Fluid and Intrauterine Growth Restriction in a Gastroschisis Fetal Rat Model

Fetuses with digestive anomalies such as gastroschisis may present intrauterine growth restriction (IUGR) and shortened intestines.

OBJECTIVE

The aim of this study was to assess the influence caused by amniotic fluid (AF) in intestinal length and somatic growth in an experimental gastroschisis fetal model at two distinct gestational ages.

MATERIAL AND METHOD

Fetal rats were operated according to Correia-Pinto on 2 different days of gestation: day 18.5 (group I) and day 19.5 (group II). Each group was divided into three sub-groups: fetuses with gastroschisis (G), control (C) and sham(S). Body measurements and histological analysis were done.

RESULT

Body measurement analysis showed: average body weight (g) in group I was G = 5.32, C = 5.68, S = 5.86; group II was G = 5.32, C = 5.80, S = 5.66. Average intestine weight (g) in group I was G = 0.283, C = 0.238, S = 0.231; group II was G = 0.272, C = 0.231, S = 0.233. Average intestine length (mm) in group I was G = 125, C = 216, S = 209; group II was G = 148, C = 226, S = 226. Histological analysis showed a decrease in the number and size of the intestinal microvillae and a light edema of serosa.

CONCLUSION

Gastroschisis had a direct correlation with IUGR and the time of exposure of the fetuses to AF had no influence on body weight in gastroschisis fetuses but did interfere with intestinal length.

Surfactant proteins SP-A and SP-D: structure, function and receptors

Surfactant proteins, SP-A and SP-D, are collagen-containing C-type (calcium dependent) lectins called collectins, which contribute significantly to surfactant homeostasis and pulmonary immunity. These highly versatile innate immune molecules are involved in a range of immune functions including viral neutralization, clearance of bacteria, fungi and apoptotic and necrotic cells, down regulation of allergic reaction and resolution of inflammation. Their basic structures include a triple-helical collagen region and a C-terminal homotrimeric lectin or carbohydrate recognition domain (CRD). The trimeric CRDs can recognize carbohydrate or charge patterns on microbes, allergens and dying cells, while the collagen region can interact with receptor molecules present on a variety of immune cells in order to initiate clearance mechanisms. Studies involving gene knock-out mice, murine models of lung hypersensitivity and infection, and functional characterization of cell surface receptors have revealed the diverse roles of SP-A and SP-D in the control of lung inflammation. A recently proposed model based on studies with the calreticulin-CD91 complex as a receptor for SP-A and SP-D has suggested an anti-inflammatory role for SP-A and SP-D in naïve lungs which would help minimise the potential damage that continual low level exposure to pathogens, allergens and apoptosis can cause. However, when the lungs are overwhelmed with exogenous insults, SP-A and SP-D can assume pro-inflammatory roles in order to complement pulmonary innate and adaptive immunity. This review is an update on the structural and functional aspects of SP-A and SP-D, with emphasis on their roles in controlling pulmonary infection, allergy and inflammation. We also try to put in perspective the controversial subject of the candidate receptor molecules for SP-A and SP-D.

Proinflammatory cytokines found in amniotic fluid induce collagen remodeling, apoptosis, and biophysical weakening of cultured human fetal membranes

The mechanisms by which fetal membranes (FM) rupture during the birth process are unknown. We have recently reported that FM weaken, at least in part, because of a developmental process of extracellular matrix remodeling and apoptosis. We now hypothesize that cytokines that normally increase in amniotic fluid at term induce FM collagen remodeling and apoptosis with concomitant weakening. Full-thickness FM fragments were cultured with (0-100 ng/ml) or without tumor necrosis factor (TNF) or interleukin 1, beta (IL1B). Physical properties were then examined with specially adapted industrial rupture strength testing equipment. Cultured FM were also evaluated for evidence of collagen remodeling and apoptosis. Cytokine-treated FM exhibited a dose-dependent decrease in strength and work to rupture. Compared with controls, the highest TNF dose caused maximal decrease in FM rupture strength (13.2 +/- 1.2 N versus 3.8 +/- 1.5 N; P = 0.0003) and work to rupture (0.035 +/- 0.005 J versus 0.005 +/- 0.002 J; P < 0.0001). The highest IL1B dose also decreased rupture strength (12.9 +/- 3.2 versus 4.6 +/- 1.1 N; P = 0.0027) and work to rupture (0.018 +/- 0.005 J versus 0.005 +/- 0.002 J; P < 0.01). Matrix metalloproteinase 9 (MMP9) protein increased, tissue inhibitor of matrix metalloproteinase 3 (TIMP3) protein decreased, and poly (ADP-ribose) polymerase (PARP1) cleavage increased with increasing TNF or IL1B doses (all P < 0.05), suggesting collagen remodeling and apoptosis. TNF and IL1B cause significant weakening of cultured FM. Both cytokines induce biochemical markers in the FM in a manner characteristic of the weak zone of FM overlying the cervix. TNF and or IL1B may be involved in the development of the weak zone of the FM.

Amniotic fluid index measurements in normal pregnancy after 28 gestational weeks

OBJECTIVE

The purpose of this study is to establish a normative scale of amniotic fluid index (AFI) or four-quadrant amniotic fluid index throughout gestation in uncomplicated singleton pregnancies, and to identify the lower and upper limits for each gestational week.

METHOD

A prospective longitudinal study was used. One hundred seventeen uncomplicated singleton pregnancies were examined every 4 weeks between 28 and 42 week's gestation. The uterine cavity was divided into four quadrants. With the use of linear-array, real-time B-scanning, the vertical diameter of the largest pocket in each quadrant was measured. The amniotic fluid index is the sum of these four quadrants.

RESULTS

The amniotic fluid index observations from regression equation curve were stratified in week-specific normative curves. The variation between mean AFI of the total population and the means of the preterm was significantly greater than term pregnancies (P<. 05). The AFI 2.5%, 5%, 10%, 90% 95% and 97.5% limits about the 50th (124 mm) were 68, 81, 90, 135, 144 and 145 mm, respectively, in term gestation. The 5th and 95th percentile serves as lower and upper limits of normal, respectively for 28-42 weeks gestation.

CONCLUSIONS

Gestational age-specific values of AFI were established, determining the significant trends of changes in the amniotic fluid volume with gestation. The normogram may have a clinical benefit to accurate, reliable and semiquantitative diagnosis of oligohydramnios and polyhydramnios.