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Kuřecí embrya jako inkubátor pro pomnožení parazitů rodu Cryptosporidium
SCHULZOVÁ, Tereza
This study aimed to determine the extent to which infection at the embryo stage can enhance the propagation of Cryptosporidium oocysts in chickens. Nine-day-old chicken embryos and one-day-old chickens were experimentally infected with different doses of Cryptosporidium baileyi and Cryptosporidium parvum oocysts. Post hatching, all chickens had demonstrable infections, and the infection dose had no effect on the course of infection. Chickens infected as embryos shed oocysts immediately after hatching and, over the course of the infection, they shed significantly more oocysts than infected oneday-old chickens. In chickens infected as embryos, C. baileyi was found in all organs except the brain, with highest infections in the trachea and oesophagus, and C. parvum was found only in the gastrointestinal tract and trachea, with highest infections in the gut and cloaca. In one-day-old infected chickens, C. baileyi was found only in the gastrointestinal tract and trachea, with highest infections in the gut. Chickens infected as embryos with C. baileyi died within 16 days of hatching. All other chickens cleared the infection within 13-25 days. Based on these findings, infection of chicken embryos could serve as a cost effective and simple model for the propagation of Cryptosporidium spp.
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Effect of temperature on arrhythmogenesis during heart development
Vostárek, František ; Sedmera, David (advisor) ; Tomek, Viktor (referee) ; Naňka, Ondřej (referee)
5 Abstract: Aims: The main objective of this work was to analyze in detail the effects of acute temperature changes on the function of isolated chick embryonic heart in vitro in comparison with natural conditions in ovo. Methods: The effects of temperature change (34 řC, 37 řC and 40 řC - hypo-, normo- and hyperthermia, respectively) on calcium dynamics in four days old isolated chick hearts in vitro were investigated by high-speed calcium optical imaging. For comparison and validation of in vitro measurements, experiments were also performed in ovo using videomicroscopy. Artificial electrical stimulation experiments were performed in vitro and in ovo to uncover conduction limits of different heart segments. Results: We observed almost linear dependence of sinus frequency on temperature in our temperature range. Sinus frequency during hypothermia and hyperthermia in vitro and in ovo changed about 20% in comparison with normothermia. We observed no significant changes in amplitude of calcium transients during temperature change to hypothermia but hyperthermia caused a significant decrease in amplitude of calcium transients (atria 35%, ventricles 38%). We observed a wide spectrum of arrhythmias, which occurred spontaneously even during normothermia in vitro. Occurrence of arrhythmias in vitro significantly...
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Effect of temperature on arrhythmogenesis during heart development
Vostárek, František
5 Abstract: Aims: The main objective of this work was to analyze in detail the effects of acute temperature changes on the function of isolated chick embryonic heart in vitro in comparison with natural conditions in ovo. Methods: The effects of temperature change (34 řC, 37 řC and 40 řC - hypo-, normo- and hyperthermia, respectively) on calcium dynamics in four days old isolated chick hearts in vitro were investigated by high-speed calcium optical imaging. For comparison and validation of in vitro measurements, experiments were also performed in ovo using videomicroscopy. Artificial electrical stimulation experiments were performed in vitro and in ovo to uncover conduction limits of different heart segments. Results: We observed almost linear dependence of sinus frequency on temperature in our temperature range. Sinus frequency during hypothermia and hyperthermia in vitro and in ovo changed about 20% in comparison with normothermia. We observed no significant changes in amplitude of calcium transients during temperature change to hypothermia but hyperthermia caused a significant decrease in amplitude of calcium transients (atria 35%, ventricles 38%). We observed a wide spectrum of arrhythmias, which occurred spontaneously even during normothermia in vitro. Occurrence of arrhythmias in vitro significantly...
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Effect of temperature on arrhythmogenesis during heart development
Vostárek, František
5 Abstract: Aims: The main objective of this work was to analyze in detail the effects of acute temperature changes on the function of isolated chick embryonic heart in vitro in comparison with natural conditions in ovo. Methods: The effects of temperature change (34 řC, 37 řC and 40 řC - hypo-, normo- and hyperthermia, respectively) on calcium dynamics in four days old isolated chick hearts in vitro were investigated by high-speed calcium optical imaging. For comparison and validation of in vitro measurements, experiments were also performed in ovo using videomicroscopy. Artificial electrical stimulation experiments were performed in vitro and in ovo to uncover conduction limits of different heart segments. Results: We observed almost linear dependence of sinus frequency on temperature in our temperature range. Sinus frequency during hypothermia and hyperthermia in vitro and in ovo changed about 20% in comparison with normothermia. We observed no significant changes in amplitude of calcium transients during temperature change to hypothermia but hyperthermia caused a significant decrease in amplitude of calcium transients (atria 35%, ventricles 38%). We observed a wide spectrum of arrhythmias, which occurred spontaneously even during normothermia in vitro. Occurrence of arrhythmias in vitro significantly...
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Effect of incubation temperature on growth of the working and conducting myocardium in the embryonic chick
Skuhrová, Kristýna ; Sedmera, David (advisor) ; Gregorovičová, Martina (referee)
It was shown almost 50 years ago that hypothermic incubation of chicken embryos results in a reduction in the size of embryos and an increase in the heart weight, presumably by hypertrophy (increase in cell volume). The chicken embryos were incubated in normothermia (37.5 ř C) and hypothermia (33.5 ř C) from the eleventh embryonic day. On the 17th day, the embryos were weighed and then their hearts were weighed. In agreement with the previous results, hypothermic embryos were 29% smaller and their hearts 18% heavier. The heart-to-body weight ratio was 67% higher in the hypothermic group. The measured cell size was very similar in the target areas and it was also between the two groups. The left ventricle width was twofold that the right one and the difference was not significantly higher in the hypothermia model. Purkinje fibers, the terminal part of the conduction system, were smaller than the working cardiomyocytes. Purkinje fibers were slightly enlarged after hypothermic incubation. The proliferation rate was measured by immunohistochemical labeling of anti-phospho histone H3. The experimental group showed much higher proliferation rate; it reached statistical significance in the right ventricle. Thus, hypothermic incubation resulted in increased growth of embryonic heart based on hyperplasia...
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Effect of temperature on arrhythmogenesis during heart development
Vostárek, František ; Sedmera, David (advisor) ; Tomek, Viktor (referee) ; Naňka, Ondřej (referee)
5 Abstract: Aims: The main objective of this work was to analyze in detail the effects of acute temperature changes on the function of isolated chick embryonic heart in vitro in comparison with natural conditions in ovo. Methods: The effects of temperature change (34 řC, 37 řC and 40 řC - hypo-, normo- and hyperthermia, respectively) on calcium dynamics in four days old isolated chick hearts in vitro were investigated by high-speed calcium optical imaging. For comparison and validation of in vitro measurements, experiments were also performed in ovo using videomicroscopy. Artificial electrical stimulation experiments were performed in vitro and in ovo to uncover conduction limits of different heart segments. Results: We observed almost linear dependence of sinus frequency on temperature in our temperature range. Sinus frequency during hypothermia and hyperthermia in vitro and in ovo changed about 20% in comparison with normothermia. We observed no significant changes in amplitude of calcium transients during temperature change to hypothermia but hyperthermia caused a significant decrease in amplitude of calcium transients (atria 35%, ventricles 38%). We observed a wide spectrum of arrhythmias, which occurred spontaneously even during normothermia in vitro. Occurrence of arrhythmias in vitro significantly...
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Effects of Mechanical Loading on Early Conduction System Differentiation
Machálek, Jakub ; Sedmera, David (advisor) ; Neckář, Jan (referee)
6 ABSTRAKT Kardiovaskulární onemocnění představují celosvětově nejčastější příčinu úmrtí. Arytmie neboli poruchy srdečního rytmu k této mortalitě přispívají nemalou měrou. Výzkum v oblasti morfologie převodního systému srdečního má více jak stoletou historii, ale oblast ontogeneze není ani v dnešní době dostatečně prozkoumána. Přitom pochopení mechanismů indukce pracovního myokardu ve specializovanou tkáň by mohl být jeden z klíčů k otevření dveří nových možností diagnostiky a terapie onemocnění v této oblasti. Cílem této práce je pochopení vlivu mechanické zátěže na vznik a vývoj převodního systému srdečního. Chci prokázat, že mechanické zatížení srdce krevním oběhem hraje v embryonálním vývoji nezastupitelnou roli v diferenciaci převodního systému srdečního (PSS). Jako model pozorování jsem si vybral kuřecí srdce. Při porovnání dat získaných na srdci ptáků a savců můžeme najít drobné odlišnosti v detailech, nicméně hlavní principy a mechanismy se zdají být stejné. Kuřecí embryo se vyvíjí 21 dní, přičemž toto časové údobí lze podle Hamburgera a Hamiltona rozdělit do 46 stádií. Zpočátku představuje srdce pouze primitivní trubici, která se stáčí v srdeční kličku. Posléze je přeměněna na zralý čtyřoddílový orgán charakteristický pro vyšší obratlovce. Tyto morfologické změny korelují i se změnami šíření...
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