Acrylamide (AA) is one of the most common toxins in foods. Its
effect on bone microstructure has not been investigated. The aim
of our study was to analyze the impact of acute exposure to AA on
femoral bone microstructure in mice. Adult animals were treated
perorally with 2 doses of AA (E1 group, 1 mg/kg b.w.) in a 24-h
period and with 3 doses of AA (E2 group, 1 mg/kg b.w.) in a 48-h
period. Mice exposed to AA had smaller sizes of primary osteon's
vascular canals. Secondary osteons were significantly smaller in
mice from E2 group; however their increased number (from 38 %
to 77 %) was identified in both E1 and E2 groups. In these groups,
a higher number of resorption lacunae (from 100 % to 122 %) was
also found. The values for bone volume, trabecular number were
increased and that for trabecular separation was decreased in mice
administered AA. Significantly higher value of bone surface was
observed in mice from E1 group whereas trabecular thickness was
increased in E2 group. The effect of AA on microstructure of
compact and trabecular bone tissues is different. In our study, one
dose of AA was used and acute effects of AA were investigated.
Therefore, further studies are needed to study mechanisms by
which AA acts on bone.
Early mouse neural stem cells (NSCs) first appear in embryonic day E5.5 and express pluripotency markers Oct4, Sox2, Nanog and early neural marker Sox1. Early NSCs are a good model for understanding the role of various pathways that control initial neural commitment. However, a protocol for differentiation of mouse embryonic stem cells (ESCs) into early NSCs by adherent monolayer culture has not yet been established. Hence, in this study, we identified the combination of growth factors and small molecules that differentiated mouse ESCs into early NSCs and supported their proliferation. Leukaemia inhibitory factor (LIF) was the first factor to be tested and it was found that ESCs can differentiate into early neurogenic lineage in the presence of LIF. However, we found that the induction is weaker in the presence of LIF as compared to cells differentiated in its absence. GSK-3 inhibitor, along with BMP and TGF-β pathway inhibitor (dual SMAD inhibition), are commonly used to sequentially direct ESCs towards NSCs. However, when we used this combination, mouse ESCs failed to differentiate into early NSCs. We observed that by adding Wnt inhibitor to the combination of GSK-3 inhibitor, BMP inhibitor, TGF-β inhibitor and LIF, it was possible to differentiate ESCs into early NSCs. qRT-PCR analysis of early NSCs illustrated that they expressed key pluripotency genes Oct4 and Nanog, albeit at levels lower than non-differentiated ESCs, along with early neural markers Sox1 and Pax6.
Taurine, a sulphur - containing amino acid, has been termed
a functional nutrient. Its synthetic form is a common ingredient
in supplements and energy drinks. There is no information
concerning taurine impact on bone microstructure after
prolonged supplemental use. Also, differences in bone
parameters of mice following taurine exposure are unknown. In
this study, a detailed microstructure of compact and trabecular
bone tissues of mice subchronically exposed to taurine was
determined. Animals (n=12) were segregated into three groups:
E1 group – mice received 20 mg/kg b.w. of taurine per day
during 8 weeks; E2 group – mice were fed by taurine at a dose
of 40 mg/kg b.w. for 8 weeks and a control (C) group. Decreased
density of secondary osteons, increased sizes of primary osteon's
vascular canals (P<0.05) were observed in taurine – treated
animals. Cortical bone thickness, trabecular thickness were
decreased (P<0.05) in E1 group, and relative volume of
trabecular bone was lower (P<0.05) in E2 group as compared to
C group. According to our results, prolonged taurine exposure at
the doses used in this study can negatively affect both compact
and trabecular bone tissues microstructure.
a1_The wide chemical diversity of estrogenic compounds precludes an accurate prediction of estrogenic activity on the basis of chemical structure or radioimmunological assay and thus requires that the potency of these compounds is defined by bioassay. The mammary duct growth response in intact prepubertal and adult gonadectomized female and male mice of the C3H/Di strain was used to assess the estrogenicity of synthetic compounds or their derivatives. The vehicle for tested compounds should be free of estrogenic and other hormonal effects. Olive oil or sunflower oil exerted estrogenic activities and were thus unsuitable as vehicles for the tested compounds. The absence of estrogenic activity, high solubility of different steroid hormones, and the low incidence of the inflammatory reactions at the injection site were achieved by using a vehicle containing benzyl alcohol, benzyl benzoate, butylhydroxyanisole, butylhydroxytoluene, ethyl oleate and ethanol. The bioassay was primarily designed to examine the effect of tested compounds on mammogenesis. The duration of hormone treatment was chosen to be long enough for induction of duct growth but too short to induce lobuloalveolar differentiation. Females were treated for 10 days, males for 15 days. The proportional volume occupied by mammary epithelial structures was estimated by the modified Chalkley's technique. The mean coefficient of variation of quantitative evaluation of 10 different mammary glands obtained by two operators varied between 3.2 and 17.4 %. The mean coefficient of variation of quintuplicate determinations of each mammary gland by one operator was 10.1 %, and 11.1 % by the other. The correlation coefficient between results of two operators was 0.994. Estrogens are primarily defined by their ability to increase the mitotic activity of female secondary sex organs., a2_However, our results have shown that progesterone alone, if administered in a high dose, stimulates mammary growth in both intact prepubertal and OV-X female mice similarly as the synthetic progestatial steroid norethindrone with inherent estrogenic properties. In contrast, progesterone alone had no effect, in young intact or adult castrated males, but norethindrone did stimulate mammary growth. These results demonstrated that the mammary gland of males is a suitable model for estrogen screening., J. Škarda., and Obsahuje bibliografii
In our previous studies, IB-MECA, an adenosine A3 receptor agonist, was found to stimulate proliferation of hematopoietic progenitor and precursor cells in mice. This property of IB-MECA was considered to be responsible for its ability to support regeneration of suppressed hematopoiesis after irradiation with sublethal doses of γ-rays when the drug was given in a postirradiation treatment regimen. This study was aimed at assessing the ability of IB-MECA to influence a 30-day survival of lethally irradiated mice. In a series of experiments, IB-MECA was administered following various lethal radiation doses in various numbers of drug doses and various administration routes. Though in some of these experiments a moderate increase in 30-day survival was observed in IB-MECA-treated mice, the differences in comparison with the controls were not significantly different. It can be inferred from these results and those of previous studies assessing the effects of IB-MECA after sublethal radiation doses that IB-MECA can probably influence only a substantially preserved hematopoiesis like that remaining after sublethal irradiation. Future studies should be aimed at evaluation of the abilities of IB-MECA to influence post-irradiation survival when administered as a part of combined treatment regimens., M. Hofer, ... [et al.]., and Obsahuje seznam literatury
Slonivinový reliéf (19,5 x 14,5 cm): nahá Danaé polosedí na posteli v ložnici, od stropu z oblaku padá déšť mincí. Napravo stojí okřídlený genius a chytá mince do ruky, vepředu na zemi sedí putto a sbírá mince, v pozadí další putto, který mince chytá do misky. Pod postelí Danaé je myš., Fučíková 1997#, II/5, and K reliéfu existuje přípravná kresba (Stockholm, Nationalmuseum, Pfaff, Danaé). Genius a putti sbírající peníze padající z nebe ukazuje, že se nejednalo o zobrazení mýtu o Danaé, ale o alegorii všemocnosti peněz. V této funkci byl mýtus o Danaé běžně používán (srov. Karr 1978), mimo jiné i na Tizianově obraze, který císař Rudolf II. získal do svých pražských sbírek v roce 1600 a který mohl být podnětem ke vzniku Pfaffova reliéfu. K emblému publikovaném Typotiem v roce 1601 na tab. 17, 10 (Typotius 1601-1603, 1, fol. 19r) je připojeno motto "Omnia subiecta auro" (na emblému je rovněž putto sbírající peníze, což je motiv, který s antickým mýtem nijak nesouvisí). Moralistní tón naznačuje také myš pod postelí Danaé.
Social communication in the house mouse relies heavily on pheromone-carrying major urinary proteins (MUPs), which delay release of pheromones thus extending longevity of the scent signal. Moreover, MUPs appear to play an important role in individual recognition. In the last few years, new research has led to some important advances. It has been shown that MUPs without their volatile ligands are able to activate neurons in vomeronasal organ and elicit behavioural and physiological responses in the signal receiver. Furthermore, increasing evidence has been found showing that, contrary to the traditional view, MUP expression is condition and state dependent, and that this variation may provide additional information about an individual. Progress has also been made in the description of MUP-like proteins in other rodents; as yet, however, the protein variability typical of the house mouse has not been observed in any other species. Despite these new results, the concept of MUPs has remained more or less unchanged from the date they were first recognized as an identity signal. The aim of this review is to summarise recent knowledge about MUPs and to discuss previous findings in the light of novel facts. Special attention is paid to the consequences the new results may have on our understanding of the individual recognition role of MUPs.
The study examined the morphological and long-term behavioral impacts of neonatal hypoxic-ischemic brain injury in a mouse model. We investigated the modification of different behavioral domains, such as spontaneous climbing, which represents fine motor skills. We also focused on sex-dependent differences during hypoxic-ischemic encephalopathy. The Rice-Vannucci model of hypoxia-ischemia was used, adjusted and adapted to 7-day-old C57BL/6NTac mice. The effects of induced hypoxia and ischemia were also studied separately. At postnatal day 60, mice underwent behavioral testing using the LABORAS apparatus. The perfusion for histological evaluation was performed one day after the behavioral analyses. In groups with separately induced hypoxia or ischemia, the observed alterations in behavior were not accompanied by morphological changes in the cortex or hippocampal formation. Female mice naturally climbed significantly more and hypoxic females reared less than hypoxic males (p<0.05). Male mice postnatally exposed to hypoxiaischemia exhibited significantly lower vertical activity and higher horizontal activity (p<0.05). Mild hypoxic damage may not be morphologically detectable but may induce substantial behavioral changes in adult mice. There were significant differences between horizontal and vertical activity in reaction to hypoxiaischemia. Our study indicates that the importance of behavioral testing is irreplaceable and may be reflected in neonatal medicine.
The Morris water maze (MWM) is one of the most common tasks used to assess spatial learning and memory ability in rodents. Genetic strain and gender are two prominent variants that influence spatial performance. Although it was reported that ICR (Institute of Cancer Research) mice exhibited an unchanged baseline performance in the training phase of the MWM task, this outbred strain has been widely used in learning and memory studies, and little is known regarding the effects of sex on behavioral performance. In this study, we demonstrated that both male and female ICR mice could complete the MWM task. Furthermore, a significant sex difference was observed, with females having shorter escape latencies and longer durations in the target quadrant in both the acquisition and test phases. Our findings emphasize the necessity of careful examination of not only the strain effect on behavioral performance but also the sex effect., J.-F. Ge, ... [et al.]., and Obsahuje seznam literatury
To further investigate the role of insulin during preimplantation embryo development, we compared the effects of insulin on the development of mouse and bovine preimplantation embryos and on cell proliferation during culture in vitro in simplex media. The influence of insulin on the development of mouse zygotes was determined during cultivation in mSOF medium, alone or supplemented with glucose. Similarly, the effects of insulin on the bovine preimplantation embryo development were studied in mSOF medium. The addition of insulin into mSOF medium enhanced significantly the number of cells per mouse blastocyst. Moreover, when mSOF medium was supplemented with insulin and 0.2 mmol.l-1 glucose, the percentage of hatched blastocysts and the mean cell number of mouse blastocysts were significantly higher. Insulin had no significant effect on the development of bovine embryos, produced by in vitro fertilization of in vitro matured oocytes. Neither the rates of developing embryos nor the mean number of cells in blastocysts were different in comparison with control embryos. Our results suggest that the in vitro development of mouse embryos could be enhanced by the addition of insulin to the culture medium and is further improved by the addition of glucose. In contrast to this our results indicate that insulin has no detectable beneficial effect on the preimplantation development of bovine embryos in mSOF medium., J. Mihalik, P. Rehák, J. Koppel., and Obsahuje bibliografii