Dozimetrie interního ozáření je oblast radiační ochrany, která se snaží stanovit dávku způsobenou přítomností radionuklidů v lidském těle. Popíšeme zde obecný přístup k hodnocení dávky a ukážeme přehled nových trendů v této oblasti. Pozornost je věnována především biokinetickým modelům a aplikacím matematických fantomů pro potřeby kalibrace měření in vivo., The assessment of the dose from internally incorporated radionuclides in a human body is the domain of internal dosimetry. This paper describes the general approach to dose assessment and discusses developments and new trends in the area. Special focus is given to biokinetic modeling and the application of mathematical models for calibration purposes of in-vivo measurements., Tomáš Vrba., and Obsahuje bibliografii
Alcohol abuse during pregnancy is a well-known factor in fetal morbidity, including smaller fetal size. We have shown that chronic hypoxia, considered the main pathogenetic factor in intrauterine growth restriction, elevates fetoplacental vascular resistance (and vasoconstrictor reactivity) and thus, presumably, reduces placental blood flow. We thus hypothesized that alcohol may affect the fetus - in addition to other mechanisms - by altering fetoplacental vascular resistance and/or reactivity. Using isolated, double-perfused rat placenta model, we found that maternal alcohol intake in the last third of gestation doubled the vasoconstrictor responses to angiotensin II but did not affect resting vascular resistance. Reactivity to acute hypoxic challenges was unchanged. Chronic maternal alcohol intake in a rat model alters fetoplacental vasculature reactivity; nevertheless, these changes do not appear as serious as other detrimental effects of alcohol on the fetus., V. Jakoubek, V. Hampl., and Obsahuje bibliografii