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BackgroundThe aims were to evaluate the effect of pregnancy on carotid artery elasticity and determine the associations between maternal lipids, endothelial function and arterial elasticity during pregnancy.MethodsWe examined 99 pregnant and 99 matched non-pregnant control women as part of a population-based prospective cohort study. Carotid artery elasticity indexes; carotid artery distensibility (CAD), Young’s elastic modulus (YEM) and stiffness index (SI) as well as brachial artery flow-mediated dilation (FMD) were assessed using ultrasound; serum lipid levels were also determined.ResultsSI was 57% and YEM 75% higher and CAD 36% lower in the third trimester group than the corresponding values in the first trimester group. Serum cholesterol and triglyceride levels were significantly higher in women at the end of the pregnancy than at the beginning of pregnancy (P < 0.001) and in controls (P < 0.001). In multivariate analysis, gestational age was the only independent correlate of arterial elasticity in pregnant women. In controls, age (P ≤ 0.001) and common carotid diameter (P = 0.001-0.029) were associated with SI, YEM and CAD.ConclusionsThe present study revealed that carotid artery elasticity declined towards the end of the pregnancy; this neither is straight correlating with maternal hyperlipidemia or the diameter of the carotid artery nor is it associated with changes in endothelial function.

In response to the growing clinico-economic need for comprehensive home-based sleep testing, we recently developed a self-applicable facial electrode set with screen-printed Ag/AgCl electrodes. Our previous studies revealed that nocturnal sweating is a common problem, causing low-frequency artifacts in the measured electroencephalography (EEG) signals. As the electrode set is designed to be used without skin abrasion, not surprisingly this leads to relatively high electrode-skin impedances, significant impedance changes due to sweating and an increased risk of sweat artifacts. However, our recent electrochemical in vitro investigations revealed that the sweat artifact tolerance of an EEG electrode can be improved by utilizing an appropriate Ag/AgCl ink. Here we have investigated in vivo electrode-skin impedances and the quality of EEG signals and interference due to sweating in the population of 11 healthy volunteers. Commercial Ag and Ag/AgCl inks (Engineered Conductive Materials ECM LLC and PPG Industries Inc.) were used to test electrode sets with differently constructed ink layers. Electrode-skin impedances and EEG signals were recorded before and after exercise-induced sweating. There was extensive variation in the electrodeskin impedances between the volunteers and the electrode positions: 14.6-200 k (PPG electrodes) and 7.7-200 k (ECM electrodes). Sweating significantly decreased (p < 0.05) the impedances in most cases. The EEG signal quality was assessed by comparing average band powers from 0.5 to 2 Hz before and after sweating. Only slight differences existed between the ECM and PPG electrodes; however, the lowest band power ratio (i.e. the smallest increase in the band power due to sweating) was achieved with ECM electrodes.

Our objective was to study the interrelationships between longitudinal movement of the wall of the common carotid artery and the conventional measures of arteriosclerosis in a large and well-characterized study population. Successful longitudinal movement analyses were performed on 292 subjects. The peak-to-peak and retrograde amplitudes of the longitudinal movement were directly correlated with carotid artery distensibility (r = 0Á21, P<0Á001 and r = 0Á23, P<0Á001, respectively) and inversely correlated with pulse wave velocity (r = À0Á14, P<0Á05 and r = À0Á17, P<0Á01, respectively). All longitudinal motion parameters were independent of brachial flow-mediated dilatation and intima-media thickness. Our findings indicate that arterial stiffening modulates longitudinal movement and, therefore, measurement of longitudinal movement can be of value in the assessment of vascular health.