Endothelial dysfunction in adolescents with arterial hypertension: results of rheovasographic evaluation and heart rate variability analysis

Background As a major regulator of local vascular homeostasis, the endothelium maintains vascular tone through the balance between vasodilatation and vasoconstriction. Upsetting this tight balance leads to endothelial dysfunction . The latter is thought to be a marker of future cardiovascular events in hypertensive patients. The purpose of this research was to assess endothelial vasomotor function with relation to heart rate variability in adolescents with arterial hypertension. Material and methods 56 adolescents (33 males, 23 females, aged 22 ± 2 years) were subdivided into equal groups (regarding gender, age, body mass index and genetic burden) according to hypertension appearance and smoking habits. All of them underwent forearm rheovasography with measurements of reactive hyperemia test heart rate variability being taken (a five-minute recording). As reliable values for evaluating endothelial function, relative changes in the peak blood flow velocity (DdZ/ /dT) and pulse blood volume (DdV) at the 1st min after reperfusion were used. The following parameters of the time (RRNN, SDNN, RMSSD, pNN50, CV) and frequency (TP, VLF, LF, HF; LF/HF) domain analysis were used for assessing heart rate modulation. Results Our analysis elicited a significant difference in both velocity and volume characteristics between hypertensive smokers and healthy individuals. Endothelial function in hypertensive non-smoking patients and normotensive smokers was also impaired. Heart rate variability was decreased and sympathetic tone prevailed in hypertensive adolescents. Both are associated with endothelial dysfunction. Conclusions Endothelial function is likely to be impaired in hypertensive adolescents, particularly among those who smoke. Moreover, heart rate variability is decreased and sympathetic tone prevails with relation to endothelial dysfunction towards the autonomic imbalance

I-131 Dose Response for Incident Thyroid Cancers in Ukraine Related to the Chornobyl Accident

Background: Current knowledge about Chornobyl-related thyroid cancer risks comes from ecological studies based on grouped doses, case–control studies, and studies of prevalent cancers

Investigation of acoustic fields in the arctic zone with uneven ice cover

A mathematical model for elastic wave propagation in an ice cover with uneven relief (hummock) has been developed. The theoretical model is based on the application of “directed” Green’s functions. We obtained numerical results for different distances between radiating and receiving antennas installed inside the ice layer and in water medium. An information-measuring system was created to investigate elastic acoustic waves along ice surface based on electo-hydraulic generator. Experiments of high-frequency acoustic signal propagation from electro-hydraulic generator in water-ice-air system were carried out. We illustrated the model validity for the investigation of hydroacoustic wave propagation in real ice conditions

Factors associated with serum thyroglobulin in a Ukrainian cohort exposed to iodine-131 from the accident at the Chernobyl Nuclear Plant.

BackgroundSerum thyroglobulin (Tg) is associated with the presence of thyroid disease and has been proposed as a biomarker of iodine status. Few studies have examined factors related to serum Tg in populations environmentally exposed to ionizing radiation and living in regions with endemic mild-to-moderate iodine deficiency.MethodsWe screened 10,430 individuals who were living in Ukraine and under 18 years of age at the time of the 1986 Chernobyl Nuclear Power Plant accident for thyroid disease from 2001 to 2003. We estimated the percent change (PC) in serum Tg associated with demographic factors, iodine-131 thyroid dose, and indicators of thyroid structure and function using linear regression. We also examined these relationships for individuals with and without indications of thyroid abnormality.ResultsMean and median serum Tg levels were higher among participants with abnormal thyroid structure/function. Percent change in serum Tg increased among females, smokers and with older age (p-values<0.001), and Tg increased with increasing thyroid volume, and serum thyrotropin (p-values for trend<0.001). We found no evidence of significant associations between iodine-131 thyroid dose and Tg. Serum Tg levels were inversely associated with iodized salt intake (PC=-7.90, 95% confidence interval: -12.08, -3.52), and over the range of urinary iodine concentration, the odds of having elevated serum Tg showed a U-shaped curve with elevated Tg at low and high urinary iodine concentrations.ConclusionSerum Tg may be a useful indicator of population iodine status and a non-specific biomarker of structural and functional thyroid abnormalities in epidemiological studies