Placental scanning with computer-linked gamma camera to detect impaired placental blood flow and intrauterine growth retardation

Climate variability and the outbreaks of cholera in Zanzibar, East Africa: a time series analysis

Global cholera incidence is increasing, particularly in sub-Saharan Africa. We examined the impact of climate and ocean environmental variability on cholera outbreaks, and developed a forecasting model for outbreaks in Zanzibar. Routine cholera surveillance reports between 1997 and 2006 were correlated with remotely and locally sensed environmental data. A seasonal autoregressive integrated moving average (SARIMA) model determined the impact of climate and environmental variability on cholera. The SARIMA model shows temporal clustering of cholera. A 1°C increase in temperature at 4 months lag resulted in a 2-fold increase of cholera cases, and an increase of 200 mm of rainfall at 2 months lag resulted in a 1.6-fold increase of cholera cases. Temperature and rainfall interaction yielded a significantly positive association (P < 0.04) with cholera at a 1-month lag. These results may be applied to forecast cholera outbreaks, and guide public health resources in controlling cholera in Zanzibar.

Ischaemic cerebral injury, intrauterine growth retardation, and placental infarction

Two hundred and twenty-five consecutive autopsies performed on fetuses >20 weeks' gestation were reviewed, and 37 growth-retarded stillborn fetuses without multiple congenital abnormalities or evidence of intrauterine infection were identified. Histological evidence of ischaemic cerebral injury was found in 31 of the 37 cases and placental infarction was seen in 26 of 36 placentas. Of the 31 cases with cerebral ischaemia, 24 had placental infarcts. Twenty-six of 27 stillborn fetuses >26 weeks' gestation showed histological evidence of cerebral ischaemia. It was concluded that in the group of growth-retarded fetuses studied, there was a high incidence of both cerebral and placental ischaemic abnormality.

Placental expression of vascular endothelial growth factor in placentae from pregnancies complicated by pre-eclampsia and intrauterine growth restriction does not support placental hypoxia at delivery

In view of the pathological placental features of pre-eclampsia and intrauterine growth restriction (IUGR), and the angiogenic effects of vascular endothelial growth factor (VEGF), the aim of this study was to determine the expression of VEGF in placentae from normal pregnancies and to compare the results with placentae from pregnancies complicated by pre-eclampsia and intrauterine growth restriction (IUGR). ELISA was used to measure circulating VEGF immunoreactivity in umbilical vein serum samples and immunohistochemistry was used to determine tissue expression of the protein. Since VEGF is known to be upregulated by hypoxia, the expression pattern of VEGF would provide further clues to the oxygen status in the placentae at the time of sampling, presently a subject under great debate. The geometric mean concentration of VEGF immunoreactivity in umbilical vein serum of normal pregnant women was 112.46 pg/ml, in women with pre-eclampsia 50.23 pg/ml and in IUGR alone 175.35 pg/ml. These values were not statistically different from each other. Immunolocalization of VEGF in normal term villous placenta was observed in the syncytiotrophoblast with less intense staining in stromal cells. No qualitative differences in localization of staining between the groups (normal pregnancies, pre-eclampsia, pre-eclampsia plus IUGR, and IUGR) was found. Intensity of staining in stromal cells was also similar in the groups studied. However, intensity of VEGF immunostaining in syncytiotrophoblast was significantly reduced in the three pathological groups (P < 0.02) compared with the control group. These results suggest that reduced VEGF may be responsible, at least in part, for the impaired vascular development which occurs in these conditions. Our results are therefore not consistent with villous placental hypoxia at the time of sample collection.

Nitric oxide concentrations are increased in the feto-placental circulation in intrauterine growth restriction

The aim of this study was to measure plasma concentrations of total nitrites, as an index of nitric oxide (NO) synthesis, in the fetal circulation of normal pregnancies and in pregnancies complicated by intrauterine growth restriction. Plasma was prepared from umbilical venous blood collected from 13 placentae from normal pregnancies complicated by intrauterine growth restriction. Plasma NO concentrations were determined using the Greiss reaction by measuring combined oxidation products of NO, plasma nitrite (NO2-) and nitrate (NO3-) after reduction with nitrate reductase. Significantly higher NO2-concentrations were found in umbilical venous plasma in the group complicated by intrauterine growth restriction compared to the control group (65.6 mumol/1, P < 0.001. These results support the hypothesis that increased NO production may be a compensatory response to improve blood flow in the placenta and/or may play a role in limiting platelet adhesion and aggregation.

The human placenta in idiopathic intrauterine growth retardation: a light and electron microscopic study

Six placentae from small for gestational age infants were examined by both light and electron microscopy. These were from pregnancies in which all maternal or fetal factors known to be associated with intrauterine growth retardation, including maternal cigarette smoking, were excluded. At the light microscopic level the only significant finding was an excess of villous cytotrophoblastic cells whilst electron microscopy showed these placentae to be characterized by villous cytotrophoblastic hyperplasia, focal syncytial necrosis, microvillous abnormalities, reduced syncytial secretory activity, irregular thickening of the trophoblastic basement membrane and the presence of small fetal villous vessels with multilayered basement membranes. It is thought that most of the observed abnormalities are due to uteroplacental ischaemia and it is possible that the fetal vascular abnormalities are a reflection of the fetal growth retardation. There is little evidence that the functional efficiency of the placenta is impaired in these cases and it is suggested that the principal factor in the pathogenesis of fetal growth retardation is a restriction of nutrient supply to the fetus because of an inadequate degree of physiological change within the maternal spiral vessels.

Uteroplacental blood flow in pre-eclampsia measurements with indium-113m and a computer-linked gamma camera

Uteroplacental blood flow was measured with a computer-linked gamma camera after intravenous injection of 1 mCi indium-113m. Results of the measurements from 32 pre-eclamptic pregnancies and 37 normal controls are compared. The uteroplacental blood flow was measured as an index calculated from the rise time and maximum activity of the isotope accumulation curve. The uteroplacental blood flow was reduced with 50% in pre-eclampsia. In severe pre-eclampsia it was more compromised than in mild pre-eclampsia. A diminished uteroplacental blood flow was found in pre-eclampsia even in the absence of intrauterine growth retardation. The maternal placental circulation in the supine position was reduced with one third compared to that in the left lateral recumbent position.

Intra-uterine growth retardation and limb deformities produced by neuromuscular blocking agents in the rat fetus

Intra-uterine growth retardation and limb deformities, resembling clubfoot, were produced by tubocuararine chloride, and by toxiferine, when administered to the rat fetus between the 16th and 19th day of gestation. These effects were associated in some fetuses, but were not sex-linked. Fetuses in the middle part of the uterine horn were observed to be more vulnerable. Placentae of the affected fetuses were smaller in size and weight at birth. Direct toxic effects of the drug on the fetus and/or on the placenta, along with immobilization of the fetus in utero due to the neuromuscular blocking action of the drugs, seem responsible for these effects. These finding warrant proper caution and care in administering such drugs to women, even as late as the third trimester of pregnancy.

Assessment of fetoplacental function by biochemical determinations

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