Flow velocity waveforms were recorded from the umbilical artery and uteroplacental arterial circulations of 15 women undergoing elective Caesarean section under extradural anaesthesia. The systolic: diastolic ratios of the flow velocity waveform were determined before and after extradural block. Extradural block did not alter fetal or maternal heart rates; however, umbilical artery systolic:diastolic ratio decreased from a mean (SD) of 2.4 (0.42) to 2.26 (0.38) (P = 0.049). There were no significant changes in the uteroplacental systolic:diastolic ratios. These results were compared with those from a control group in which no statistically significant changes in maternal and fetal systolic:diastolic ratios or heart rates were observed. The application of a pulse correction factor to standardize the data to fixed maternal and fetal heart rates had little effect on the significance of the findings. Extradural block in normal pregnant women during late gestation was associated with a small reduction in umbilical artery systolic:diastolic ratios, suggesting a decrease in downstream fetoplacental vascular resistance.

The chicken retina has been used to examine the toxicity of a highly reactive chemical analog of choline, ethylcholine mustard aziridinium ion (ECMA). Following a single intravitreal injection, retinas were analyzed biochemically for CAT and AChE activities, and GABA, glycine, and dopamine levels. Retinas were also examined using histofluorescence for dopamine histochemistry, for AChE, and immunohistochemistry with antibodies to CAT, tyrosine hydroxylase, GABA, 5-HT, Leu-enkephalin, and somatostatin. A dose of 50 nmol ECMA caused a prolonged 70% depletion of CAT activity and a 40% depletion of AChE activity. The other biochemical parameters were unchanged. This result corresponds to the morphological finding that 2 populations of cholinergic cells were destroyed and that the AChE activity associated with their terminal arbors was lost. A third population of cholinergic cells, located towards the middle of the inner nuclear layer, was resistant to the toxic effects of ECMA. The other cell types, except for somatostatin-immunoreactive cells and photoreceptors, which showed transient effects, were unaffected. ECMA therefore appears to be a highly specific toxin for cholinergic cells in the retina.

Conclusions: This is the first demonstration of lymphocyte adhesion supported by a CXC chemokine and suggests that CXCL16 has the ability both to attract and then to retain lymphocytes at epithelial surfaces thereby promoting bile duct damage in inflammatory liver disease.

a strong predictor. The 'U' shaped relationship between IL-6 levels and PTD may indicate that women who do not mount a sufficient inflammatory response and women with a highly active inflammatory response are both at increased risk of PTD.Asthma can place a major burden on affected children and their families. Previous studies have focused on the association between outdoor air pollution and asthma prevalence and morbidity. The purpose of this study is to examine the association between chronic exposure to outdoor air pollutants and asthma prevalence and exacerbation in children residing in metropolitan counties in the United States. The authors linked asthma status information for children in the 1997 and 1998 National Health Interview Surveys with a county-level outdoor air pollution index, an aggregate index of measured levels of five pollutants. Of the 16 153 children included in the study, 938 (5.9%) had active asthma; further, 367 (36.9%) of the 938 children with asthma reported having at least one emergency room visit in the previous 12 months. The authors found that children living in counties in the upper three quartiles of the outdoor air pollution index were more likely to have active asthma than children living in counties in the lowest quartile (Adjusted OR 1.19, 95% CI = 0.93, 1.54). Similarly, among children with asthma, those living in counties in the upper three quartiles of the air pollution index had an increased odds of experiencing an asthma-related emergency room visit compared with children living in counties in the lowest quartile (Adjusted OR 1.69, 95% CI = 1.11, 2.59). This study suggests that residing in a metropolitan county with higher outdoor air pollution levels is associated with active asthma in children and with increased asthma-related emergency room visits.

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