Melatonin reduces inflammation and cell death in white matter in the mid-gestation fetal sheep following umbilical cord occlusion

The premature infant is at increased risk of cerebral white matter injury. Melatonin is neuroprotective in adult models of focal cerebral ischemia and attenuates ibotenate-induced white matter cysts in neonatal mice. Clinically, melatonin has been used to treat sleep disorders in children without major side effects. The aim of this study was to investigate the protective and anti-inflammatory effects of melatonin in the immature brain following intrauterine asphyxia. Fetal sheep at 90 d of gestation were subjected to umbilical cord occlusion. Melatonin (20 mg/kg, n = 9) or vehicle (n = 10) was administered IV to the fetus, starting 10 min after the start of reperfusion and continued for 6 h. Melatonin treatment resulted in a slower recovery of fetal blood pressure following umbilical cord occlusion, but without changes in fetal heart rate, acid base status or mortality. The production of 8-isoprostanes following umbilical cord occlusion was attenuated and there was a reduction in the number of activated microglia cells and TUNEL-positive cells in melatonin treated fetuses, suggesting a protective effect of melatonin. In conclusion, this study shows that melatonin attenuates cell death in the fetal brain in association with a reduced inflammatory response in the blood and the brain following intrauterine asphyxia in mid-gestation fetal sheep.     

Developmental effects on neonatal mortality and subsequent cerebral palsy in infants exposed to intrauterine infection

BACKGROUND: Intrauterine bacterial infection is important as a high risk factor associated with subsequent brain damage of the newborn. AIMS: To see if mature fetuses require both hypoxia and intrauterine infection to lead to cerebral palsy, while premature fetuses need infection alone. STUDY DESIGN: A retrospective cohort study. SUBJECTS: 230 singleton live-born infants of 22 to 32 weeks of gestation, exposed to intrauterine infection during labor and delivery, from 1995 to 2002. METHODS: Mortality and incidence of cerebral palsy at 2 years old were compared among the 3 groups; immature (n=89, 22-27 weeks), premature (n=73, 28-33 weeks) and mature (n=68, >34 weeks). The relationship between cerebral palsy and fetal pH values was examined. OUTCOME MEASURES: Mortality and cerebral palsy. RESULTS: Mortality and cerebral palsy were significantly decreased with advancing gestation. Mortality was significantly decreased after 28 weeks of gestation while cerebral palsy was significantly decreased after 34 weeks of gestation. Acidosis was associated with cerebral palsy in mature infants, but not in less mature infants. CONCLUSIONS:: Premature infants were more susceptible to intrauterine infection to cause death or cerebral palsy than mature infants. Mature infants may require exposures to both infection and hypoxia but less mature infants need infection alone to cause cerebral palsy, suggesting different pathogenesis during the developmental stage.     

Spectral power differences in the brain activity of growth-restricted and normal fetuses

Using non-invasive fetal magnetoencephalography (fMEG), we investigated spontaneous brain activity in 28 fetuses diagnosed with intrauterine growth restriction (IUGR) and compared the results to 47 normal-growth fetuses. The fetal gestational age ranged from 28 to 39 weeks with post-natal recordings obtained on 17 of the IUGR fetuses. Power spectrum was computed and was divided into four frequency bands. A significant difference in the relative spectral power in delta, theta and beta bands (P<0.01) was observed only in the 28-32 week gestation age group with alpha band showing a similar trend (P=0.054). This observation suggests that growth restriction may have a more pronounced effect on the fetal brain in early gestation. Larger population studies could reveal the potential value of fMEG as an additional surveillance tool for growth-restricted fetuses.     

Periodic spectral components of fetal heart rate variability reflect the changes in cord arterial base deficit values: a preliminary report

Fetal distress changes the function of the autonomic nervous system. These changes are reflected in the fetal heart rate and can be quantified with power spectrum analysis of heart rate variability. The purpose of this study was to find out whether spectral components of fetal heart rate variability (FHRV) during labor are associated with fetal cord arterial base deficit values at birth. The association between FHRV and umbilical cord arterial base deficit was studied in 14 singleton fetuses with normal pregnancy at 35–40 weeks of gestation. Fetal ECG was recorded by scalp-electrode using a STAN^® Fetal ECG monitor (Cinventa Ab, Mölndal, Sweden). FHRV was quantified by computing Fast-Fourier-transformed heart rate (HR) spectra at three frequency bands: low-frequency (LF) 0.03–0.07 Hz, mid-frequency (MF) 0.07–0.13 Hz and high-frequency (HF) 0.13–1.0 Hz. We found that total FHRV and MF FHRV were lower in fetuses with cord arterial base deficit 8 to 12 mmol/L in comparison to the fetuses with normal cord arterial base deficit value (P=0.02 and P=0.01, respectively). A linear correlation was found between the spectral densities and the cord arterial base deficit values (r=0.4 and r=0.6, respectively). We conclude that the results suggest changes in the autonomic nervous cardiac control in fetuses with cord arterial base deficit between 8 to 12 mmol/L. The clinical applicability of our observations on FHRV in predicting fetal distress remains to be further studied.     

褪黑素对肺炎链球菌溶血素致大鼠脑损伤细胞凋亡的影响

目的 探讨褪黑素(MT)对肺炎链球菌溶血素(PLY)致脑损伤细胞凋亡的影响.方法 幼鼠84只随机分成3组:9 g·L-1盐水组(NS组)28只,颈内动脉注射9 g·L-1盐水;PLY组28只,颈内动脉注射0.2 mL(7 μg)PLY; MT组28只,腹腔注射(1 g·L-1)MT 10 ng·kg-1,15 min后颈内动脉注射0.2 mL(7μg)PLY.每组按照注射后不同的时间点(24 h、48 h)分为2个亚组.预定时间点处死动物,制备脑组织标本.干湿质量法测定其脑组织含水量( BWC),甲酰胺法测定伊文思兰(EB)水平,免疫组织化学技术测定凋亡诱导因子(AIF)表达,原位末端标记法检测细胞凋亡.结果　HE染色光镜下可见PLY组血管间隙增宽,大脑皮质炎性细胞浸润,胶质细胞和神经无细胞有不同程度肿胀、空泡变性.NS组无上述病理变化.MT组大鼠脑组织改变较PLY组轻.PLY组各时间点脑组织BWC水平、EB水平、AIF水平明显增加,24h高于48 h,差异有统计学意义.PLY组各时间点凋亡细胞数明显增加,48 h高于24h,差异有统计学意义.各时间点PLY组与对照组比较均有统计学差异.予以MT干扰后各时间点脑组织各指标以及凋亡细胞数均降低,与PLY组比较,差异有统计学意义.结论　MT能够降低AIF表达,减少神经细胞凋亡,保护脑组织.     

Habituation in fetuses of diabetic mothers

Fetuses of diabetic mothers exhibit maturational delays in their behaviour and disturbances in behavioural and intellectual functioning in childhood. This suggests an effect of maternal diabetes on the central nervous system of the fetus. The habituation technique enables the functioning of the higher central nervous system to be examined. A normal habituation pattern reflects an intact central nervous system. Previous studies have found abnormalities in the fetal central nervous system are reflected in habituation performance. This paper examined the habituation ability of fetuses of diabetic mothers and of non-diabetic mothers. The fetuses were tested at 28, 32 and 36 weeks of gestation. After 2 min of fetal inactivity a series of vibroacoustic stimuli were presented to the fetus. This continued until no response was observed on five consecutive stimulus presentations. The number of stimulus presentations to habituate at each gestational age was recorded. The results reveal that there was a highly significant main effect of group (F(1,47)=19.65, P<0.001). Fetuses of diabetic pregnancies took longer to habituate. There was a significant effect of gestational age (F(2,94)=44.67, P<0.0001). In both groups the number of trials to habituate decreased with advancing gestation. There was no relationship between random blood glucose levels and habituation performance. The results demonstrate that maternal diabetes affects higher aspects of central nervous system functioning in the fetus.     

汉防己甲素对先天性膈疝大鼠模型胎仔肺发育不良的影响及意义

目的 探讨产前应用汉防己甲素(TET)对先天性膈疝(CDH)大鼠模型胎仔肺内表面活性蛋白B(SP-B)和增殖细胞核抗原(PCNA)的影响及意义.方法 10只成年雌性SD大鼠配种后,于孕9.5 d随机分为3组:对照组(2只)、膈疝组(4只)和治疗组(4只),膈疝组和治疗组一次性灌胃给予除草醚125 mg/只(溶于2.5ml橄榄油中),对照组灌胃给予等量橄榄油.配种后18.5 d时,治疗组给予30 mg/kg汉防己甲素灌胃(1次/d,连续3 d),膈疝组和对照组给予等量生理盐水.孕21 d对孕鼠行剖宫产,观察胎鼠膈疝形成情况,取出肺组织行HE染色并行图像分析,采用免疫组化染色法检测胎肺内SP-B和PCNA的表达情况.结果膈疝组和治疗组共有48只胎鼠形成膈疝,其致畸率为64.9%,二组之间致畸率差别无统计学意义(P>0.05).膈疝组胎鼠存在肺发育不良,产前给予TET干预,肺组织在形态上有明显改善,外形接近于对照组.正常肺组织中,SP-B在肺泡上皮细胞及远端支气管上皮细胞的胞浆内表达,在膈疝组中未见SP-B表达.治疗组中可见SP-B表达,但低于对照组(P<0.01).PCNA阳性细胞率在对照组与膈疝组的差异无统计学意义(P>0.05),但在治疗组中其表达显著较前二组为低,差异有统计学意义(P<0.01).结论 产前应用TET可诱导CDH胎鼠肺的成熟,促进肺内SP-B表达升高;同时,产前给予TET干预的CDH胎鼠,其肺内PCNA阳性细胞率明显降低,提示TET诱导CDH胎肺的成熟并不是依靠促进细胞增殖来完成的.     

Fetal aortic blood flow assessment from the relationship between fetal aortic diameter pulse and flow velocity waveforms during fetal development

BACKGROUND: Blood flow is calculated from mean velocity across the vessel and its cross-sectional area and is related to the fetal growth. AIM: To investigate the relationship between diameter pulse waveform (DPW) and flow velocity waveform (FVW) in the fetal descending aorta during fetal development. STUDY DESIGN: Doppler ultrasound and a phase-locked loop echo tracking system were used to measure the FVW and DPW in the fetal descending aorta, respectively. SUBJECTS: We studied 137 normal-growth fetuses (normal group, 20-40 weeks) and 51 fetuses with high umbilical artery pulsatility index (umbilical placental insufficiency, UPI group, 26-40 weeks). OUTCOME MEASURES: We measured the systolic (Sd), diastolic (Dd) diameters, time diameter integral (TDI) and time velocity integral (TVI) and then calculated the TVI x TDI and TVI to TDI ratio. RESULTS: Normal fetal growth was associated with an increase in Sd, Dd, pulse amplitude, TVI, TDI and TVI x TDI. The FVW began to resemble the DPW with decreasing downstream resistance produced by growth of the placenta. The TVI was increased relative to the TDI. The differences in Sd, Dd, TDI and TVI x TDI between the normal and UPI groups were not significant. The TVI was decreased relative to the TDI. There was a decrease in the TVI as a ratio of the TDI. The Dd per unit fetal weight was high in the compromised fetuses. Fetal outcome was examined in relation to the TVI to TDI ratio. Those with a low ratio (below 10th centile) exhibited significantly more adverse indices of fetal outcome. CONCLUSIONS: In fetal compromise there is an increase in diastolic pressure in association with high placental resistance, which causes a major increase in afterload. The efficient circulation associated with fetal growth might be represented by an increase in the ratio of the TVI to the TDI (an index of efficient circulation) when these waveform shapes resemble each other.     

地塞米松预处理对新生大鼠缺氧缺血后脑内NF-κB活性及神经细胞凋亡的影响(英文)

目的：探讨地塞米松预处理对新生大鼠缺氧缺血后脑内NF κB活性及神经细胞凋亡的影响。方法：4 2只新生大鼠随机分为 5组 ,即正常对照组 (n =8) ,假手术组 (n =8) ,缺氧缺血组 (HIBD ,n =8) ,地塞米松治疗组 (DEX ,n =9)及地塞米松预处理组 (P DEX ,n =9)。于缺氧缺血 (HI)后 72h取脑 ,以Western印迹法检测脑组织中NF κB抑制蛋白IκBα表达 ,TUNEL法检测细胞凋亡 ,免疫组织化学法检测NF κB亚基p6 5核移位情况 ,免疫荧光双标法检测P6 5核移位与细胞凋亡共表达。结果：与正常对照组和假手术组比较 ,HIBD组及DEX组 p6 5阳性细胞及TUNEL阳性细胞数明显增加 (P <0 .0 1) ,IκBα蛋白表达明显减少 (P <0 .0 1)。P DEX组也可见p6 5阳性细胞及TUNEL阳性细胞表达 ,但较HIBD组及DEX组明显减少 (P <0 .0 1) ,而IκBα蛋白表达明显增多 (P<0 .0 1)。直线回归分析显示 ,在HIBD组中NF κB的活化与缺氧缺血后神经细胞凋亡密切相关 (r =0 .775 ,P <0 .0 1)。结论：NF κB的活化与缺氧缺血后神经细胞凋亡密切相关。DEX预处理对缺氧缺血性脑损伤的保护作用可能与抑制NF κB的活化 ,减少细胞凋亡有关。     

Structural congenital brain disease in congenital heart disease: Results from a fetal MRI program

ObjectiveTo identify the type and incidence of fetal brain pathology in fetuses with a prenatal diagnosis of congenital heart disease (CHD).Patients and methods67 pregnant women underwent a fetal MR-examinations between 20 and 38 gestational weeks. MR was done on a 1.5 T superconducting system. The type of cardiac malformation was defined by fetal echocardiography. Fetuses with a chromosomal abnormality or an extracardiac anomaly were excluded.ResultsFetal MRI scans in the final study cohort (53 fetuses) yielded normal results in 32 fetuses and a brain abnormality in 21 fetuses. Congenital brain disease (CBD) was found in 39% of the final study cohort of fetuses with CHD. MRI findings were classified into malformations, acquired lesions and widening of the ventricles and/or outer CSF spaces (malformations: 7 fetuses, acquired lesions: 5 fetuses, changes in CSF spaces: 9 fetuses). Asymmetry of the ventricles was the most common finding in the CSF group.ConclusionsOur data suggest that fetal MRI can be used to characterize structural CBD in CHD. Advanced MRI techniques such as diffusion tensor imaging and proton spectroscopy are tools that, in the future, will certainly shed light on the spectrum of structural and functional CBDs that are associated with CHD.     

Fetal CNS damage after exposure to maternal trauma during pregnancy

Nine case reports are presented to indicate the possible effects of maternal trauma on surviving fetuses. Previous reports have only addressed fatal consequences. Traumata occurred between gestational weeks 23 and 37. Seven mothers had motor-vehicle accidents (MVA), two had blunt abdominal traumata. Four mothers suffered severe injuries, such as cerebral contusion, fractures or placental abruption leading to emergency Cesarean section. Premature uterine contractions were observed in five mothers and hemorrhage in two. The nine children were born after 30 to 40 weeks of gestation. Seven had normal postpartal vital signs, one required resuscitation and one premature needed assisted ventilation. Clinical symptoms were variable: movement disorders ( n = 3), hydrocephalus ( n = 2), convulsions ( n = 1), cerebral palsy ( n = 1), normal ( n = 3). Follow-up ranged from 7 months to 5 years. Neuroimaging revealed periventricular leukomalacia ( n = 2), localized vascular infarctions ( n = 2), hemorrhage ( n = 1), hydrocephalus ( n = 2) and global brain damage ( n = 1). The causative role of maternal accidents was extremely likely in one patient, and probable but unproved in the remaining cases.     

Human fetal and maternal corticotrophin releasing hormone responses to acute stress

OBJECTIVES: To study the effect of acute stress, caused by intrauterine needling at the intrahepatic vein (IHV), on fetal plasma concentrations of corticotrophin releasing hormone (CRH), and to compare paired fetal and maternal samples for CRH concentration to determine the extent of their joint control. DESIGN: Venous blood samples were obtained from fetuses (gestational age 17-38 weeks) undergoing fetal blood sampling (n = 29) or intrauterine transfusion (n = 17) through either the IHV or the placental cord insertion (PCI). SETTING: The Centre for Fetal Care, Queen Charlotte's and Chelsea Hospital, London, UK. PATIENTS: Pregnant women undergoing clinically indicated fetal blood sampling or intrauterine blood/platelet transfusion. RESULTS: Fetal plasma cortisol increased with intrahepatic vein transfusion (mean (SD) cortisol response Delta64.7 (54.5) nmol/l; p < 0.0001, n = 11), and fetal corticotrophin concentrations were higher after IHV (n = 7) than PCI needling (n = 6). Neither fetal nor maternal plasma CRH increased after IHV transfusion. Fetal CRH levels did not rise with gestation, whereas maternal CRH levels did (r = 0.58; n = 36; p < 0.0001). There was a modest correlation between paired maternal and fetal values (r = 0.36; n = 36; p = 0.03). CONCLUSIONS: Acute fetal stress, caused by IHV needling of the fetal abdomen, resulted in hypothalamic-pituitary-adrenal axis activation, as shown by a rise in fetal cortisol and corticotrophin. However, it did not result in measurable CRH release into fetal plasma. This suggests that fetal plasma CRH is not derived from the hypophyseal-portal circulation, but from another source, presumably the placenta.     

Effects of maternal bilateral adrenalectomy and betamethasone administration on fetal rat encephalic development

The present study examined the effects of maternal bilateral adrenalectomy and betamethasone treatment on fetal encephalic development, in terms of fetal body weight, brain weight, DNA, protein and lipid content and morphological development. Both influenced the developmental time patterns of fetal brain and cerebellum. Fetuses of adrenalectomized rats had decreased body weights, whereas brain weight was not affected. Maternal adrenalectomy produces in fetal brain a decreased number of cells and increased cell size, while betamethasone treatment of adrenalectomized rats increased cell number, which was not different from control values; cell size remained lower than in control fetuses. Lipid content was increased in the fetuses of betamethasone-treated rats. In terms of morphological development, laminated structures (hippocampus and brain and cerebellar cortex) were the ones most affected.     

Calpain抑制剂-3对新生大鼠脑缺氧缺血后海马CA1区Caspase-3表达和神经元凋亡的影响

目的：钙依赖中性蛋白酶Calpain的活化可引起神经元凋亡,其抑制剂3(MDL28170)对成年动物脑缺血有治疗作用,但尚不清楚MDL28170对新生动物缺氧缺血性脑损伤(HIBD)是否也有治疗作用。本研究观察了MDL28170对新生大鼠HIBD后海马CA1区Caspase3表达及细胞凋亡的影响,探讨其神经保护作用机制。方法：将7日龄新生SD大鼠随机分为HIBD模型组(n=40)、干预组(n=40)及对照组(n=8),干预组在HI后0h、2h、4h予腹腔注射MDL2817050mg/kg,模型组和对照组同时予腹腔注射生理盐水。干预组和模型组大鼠在HI后6h、12h、24h、48h、72h各处死8只,用免疫组化染色和脱氧核糖核酸末端转移酶介导的原位缺口末端标记法(TUNEL)分别检测海马CA1区Caspase3的表达和神经凋亡。结果：HIBD组大鼠损伤侧海马CA1区Caspase3阳性细胞在HI后6h时较对照组增多(13.4±3.5/HPvs2.6±0.6/HP,P=0.028),于48h(27.1±4.1/HP)达到高峰,72h仍高于对照组(22.6±4.8/HP,P<0.001);TUNEL阳性细胞于HI后6h开始增多,12h时与对照组比较差别有显著性(25.0±1.7/HPvs2.3±1.5/HP,P<0.001),48h(67.8±2.6/HP)到达高峰,72h仍处于较高水平(44.3±6.8/HP)。MDL28170干预可明显减少Caspase3及TUNEL阳性细胞数量,与模型组比较48h内差异有显著性,72h以后作用不明显。结论：MDL28170可通过抑制海马CA1区Caspase3的表达,减少脑细胞凋亡,起到脑保护作用。     

To what extent does a given heart rate correlate with following heart rates in the developing human fetus?

To quantitatively determine the extent to which a given heart rate correlates with the following heart rate(s) at any gestational age, we studied 181 uncomplicated human fetuses between 23 and 41 weeks gestation. A continuous 90–120 min observation was made for each case using external Doppler-ultrasound cardiotocography. For every individual fetal heart rate dataset, ‘probability distribution matrices’ were calculated with fetal heart rates (termed FHRs) at 1-beat/min (bpm) intervals, and the beat-to-beat(s) difference (termed DFHR_n: 1 ≤ n ≤ 1000), also at 1-bpm intervals arranged in rows and columns, respectively, with probability in each element. Using ‘piecewise linear regression’, (1) the difference between the DFHR₁ (n = 1) probability distribution matrix as the ‘control’ and a given DFHR_n (n ≥ 2) probability matrix as the ‘variable’, was analyzed to obtain the statistically critical point(s) (termed ‘beat-delay’ in beats) for each fetus, and (2) a scattergram of ‘beat-delay’ vs. gestational age-group, made from all fetuses studied, was analyzed to reveal any critical age(s) in gestation. One statistically significant point was evident at 28–29 weeks gestation. During the period prior to the critical point, a linear decrement in ‘beat-delay’ with 21 beats (mean) at 23–25 weeks to 11 beats at 28–29 weeks gestation was noted, suggesting that the conduction system-oriented heart beat gradually comes under functional control of the autonomic nervous system as well as under possible regulation by the maturating medulla oblongata. From the critical point, through to term, there was no significant change in ‘beat-delay’ ranging from 7–11 beats, thereby implying that the fetal heart rate becomes stabilized as a result of the control rendered by the more developed autonomic nervous system function. Whether or not brain function cephalad to the medulla oblongata actually participates in this phenomenon remains to be elucidated.     

Maturation of the human fetal startle response: Evidence for sex-specific maturation of the human fetus

Despite the evidence for early fetal experience exerting programming influences on later neurological development and health risk, very few prospective studies of human fetal behavior have been reported. In a prospective longitudinal study, fetal nervous system maturation was serially assessed by monitoring fetal heart rate (FHR) responses to vibroacoustic stimulation (VAS) in 191 maternal/fetal dyads. Responses were not detected at 26 weeks gestational age (GA). Sex-specific, age-characteristic changes in the FHR response to VAS were observed by 31 weeks' GA. Males showed larger responses and continued to exhibit maturational changes until 37 weeks' GA, females however, presented with a mature FHR startle response by 31 weeks' GA. The results indicate that there are different rates of maturation in the male and female fetuses that may have implications for sex-specific programming influences.     

Quality control of prenatal sonography in detecting trisomy 18. The value of perinatal autopsy

AIMS: This study was designed to compare the prenatal ultrasound findings and postmortem pathologic findings of fetuses with trisomy 18. STUDY DESIGN: Of 22,150 fetal chromosome analyses, 70 fetuses with trisomy 18 were diagnosed between 1990 and 2004. Sonographic and perinatal autopsy findings were compared by organ system and their correlation was assigned to 1 of 3 categories. RESULTS: There were 164 separate major structural abnormalities found on autopsy. Of them, sonography detected 72 (43.9%). Among major defects the agreement was more than 75% of all abnormalities of these systems: central nervous system (80%), abdominal abnormalities (87.5%) and cystic hygroma (100%). Whereas, the sensitivity of sonography was lower in these organ systems: cardiac system (66.6%), facial abnormalities (26.3%), urinary system (27.3%) and extremities (8.7%). The rate of additional findings at autopsy was 56.1% and involved mainly 2 organ systems: face (including ear) and extremities (including hands and feet). Some ultrasound findings (n=15) were not confirmed at autopsy in our series. CONCLUSIONS: This study confirms that perinatal autopsy provides additional information in many fetuses with trisomy 18. Besides obstetricians, pediatricians and geneticists, specialized perinatal pathologists have an important role in the multidisciplinary management of prenatally diagnosed fetal malformations. In addition, examining the correlation between sonography and pathologic findings may indicate potential markers for sonographic screening of trisomy 18.     

Chaotic and periodic heart rate dynamics in uncomplicated intrauterine growth restricted fetuses

We studied how chaotic and periodic heart rate dynamics differ between normal fetuses (n = 192) and uncomplicated intrauterine growth restricted fetuses (n = 86), aged 31-42 weeks of gestation. We analyzed each fetal heart rate time series for 25 min. We quantified the chaotic dynamics of each fetal heart rate time series by correlation dimension. The periodic dynamics were analyzed by power spectral analysis. The correlation dimension and, therefore, the complexity, of the heart rate dynamics of the uncomplicated intrauterine growth restricted fetuses was significantly lower than that of the normal fetuses, which was marked at 38-42 weeks of gestation. The low-frequency (0.04-0.15 Hz) component and, therefore, the periodicity of the low-frequency range was significantly higher than that of the normal fetuses during all the gestational weeks. These results mean that, although the intrauterine growth restricted fetuses are not severely compromised, the overall integrity of their cardiovascular control is impaired, especially at term; and sympathetic modulation is increased, both of which may contribute to increased perinatal mortality.     

Lung maturation in the hyperinsulinemic rat fetus

Hyperinsulinemic rat fetuses were obtained either by repeated in utero injections of long-acting insulin (resulting in fetal hypoglycemia) or by chronically infusing intravenous glucose to the mother (resulting in fetal hyperglycemia). Fetuses were examined at term. In insulin-injected fetuses (n = 15), surfactant (S) fraction phosphatidylcholine (PC) and disaturated phosphatidylcholine (DSPC) were significantly decreased (3.6 +/- 0.1 nmol Pi/mg tissue; p less than 0.001 and 2.8 +/- 0.1 nmol/mg; p less than 0.025, respectively) as compared with their saline-injected controls (4.8 +/- 0.2 and 3.3 +/- 0.1 nmol/mg, respectively, n = 19). However, residual (R) fraction was unchanged, and there was no difference in whole-lung phospholipids (combined S and R fractions). These results are consistent with morphological data showing a lower lamellar body area per type II cell profile in insulin-injected fetuses as compared with their controls [1.41 +/- 0.13 micron 2 (n = 72) versus 1.99 +/- 0.14 micron 2 (n = 129) p less than 0.01]. Glycogen content was slightly higher in insulin-injected fetuses (18.5 +/- 1.0 micrograms/mg, n = 17) than in their controls (15.1 +/- 0.8 micrograms/mg, n = 18; p less than 0.05). In the second model, changes in S fraction PC and DSPC were similar to those observed after insulin-injections: 4.3 +/- 0.25 and 3.4 +/- 0.2 nmol Pi/mg in fetuses of glucose-infused rats (n = 10) versus 5.7 +/- 0.45 and 4.3 +/- 0.3 nmol Pi/mg, respectively, in controls (n = 10, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)