181 research outputs found

    Isoform specific expression of ∆9 desaturases in two brain regions of common carp

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    An appropriate ratio of saturated and unsaturated fatty acids contributes to membrane fluidity. The ∆9 stearoyl-CoA desaturases are key enzymes involved in the regulation of the lipid composition of cellular membranes. The expressions of the ∆9 stearoyl-CoA desaturase genes are regulated by many environmental factors, such as temperature changes and metal exposure, mostly at the levels of transcription and mRNA stability. The present study analyzes the effects of cold shock and Cd2+ treatment on the regulation of two ∆9 desaturase genes in the olfactory lobe and the cerebellum of common carp. The effect of Cd2+ was also followed on the expressions of the ∆9 desaturase genes of cold-shocked animals. Sudden cold shock or Cd2+ exposure induced ∆9 desaturase expressions in a time-, brain region- and isoform-specific man-ner. In contrast, both ∆9 desaturase genes were repressed by Cd2+ in cold-shocked animals

    Major differences in the levels of redox status and antioxidant defence markers in the erythrocytes of pre- and full-term neonates with intrauterine growth restriction

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    Intrauterine growth restriction (IUGR) is a pleiotropic complication of pregnancy. Prematurity and growth abnormalities are common risk factors for perinatal morbidity and mortality. Free radical damage has been recognized as a common pathogenic mechanism of many neonatal diseases. The aim of the present study was to characterize the possible links between the level of maturity, the birthweight and the antioxidant status of neonates born with IUGR. Our data suggest that the stress markers measured on the cord blood of neonates with IUGR and mature, healthy neonates do not necessarily reflect the extent of oxidative stress. However, significant correlations were found between the maturity of the neonates with IUGR and the oxidative damage. The mature IUGRs exhibited ONOO- accumulation and increased lipid peroxidation more frequently as compared with the pre-term group. The results suggest that the oxidative injury in IUGR may depend on the level of maturity and the birthweight.keywords: antioxidant defence, IUGR, oxidative stress, peroxynitrite, umbilical cord blood

    Molecular Study on Twin Cohort with Discordant Birth Weight

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    The increased rate of twinning has pointed out newer challenges in clinical practices related to gestational complications, intrauterine growth restriction, perinatal mortality, and comorbidities. As a twin pregnancy progresses, the increased demand for oxygen supply can easily disrupt the redox homeostasis balance and further impose a greater challenge for the developing fetuses. A substantial birth-weight difference acts as an indicator of a deficit in oxygenation or blood flow to one of the fetuses, which might be related to a low bioavailable nitric oxide level. Therefore, in this study, we focused on networks involved in the adjustment of oxygen supply, like the activation of inducible and endothelial nitric oxide synthase (NOS3) along with free radical and lipid peroxide formation in mature twin pairs with high birth-weight differences. The selected parameters were followed by immunofluorescence staining, fluorescence-activated cell sorting analysis, and biochemical measurements in the umbilical cord vessels and fetal red blood cells. Based on our data set, it is clear that the lower-weight siblings are markedly exposed to persistent intrauterine hypoxic conditions, which are connected to a decreased level in NOS3 activation. Furthermore, the increased level of peroxynitrite aggravates lipid peroxidation and induces morphological and functional damage and loss in redox homeostasis

    A role of the LIM-homeobox gene Lhx2 in the regulation of pituitary development

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    AbstractThe mammalian pituitary gland originates from two separate germinal tissues during embryonic development. The anterior and intermediate lobes of the pituitary are derived from Rathke's pouch, a pocket formed by an invagination of the oral ectoderm. The posterior lobe is derived from the infundibulum, which is formed by evagination of the neuroectoderm in the ventral diencephalon. Previous studies have shown that development of Rathke's pouch and the generation of distinct populations of hormone-producing endocrine cell lineages in the anterior/intermediate pituitary lobes is regulated by a number of transcription factors expressed in the pouch and by inductive signals from the ventral diencephalon/infundibulum. However, little is known about factors that regulate the development of the posterior pituitary lobe. In this study, we show that the LIM-homeobox gene Lhx2 is extensively expressed in the developing ventral diencephalon, including the infundibulum and the posterior lobe of the pituitary. Deletion of Lhx2 gene results in persistent cell proliferation, a complete failure of evagination of the neuroectoderm in the ventral diencephalon, and defects in the formation of the distinct morphological features of the infundibulum and the posterior pituitary lobe. Rathke's pouch is formed and endocrine cell lineages are generated in the anterior/intermediate pituitary lobes of the Lhx2 mutant. However, the shape and organization of the pouch and the anterior/intermediate pituitary lobes are severely altered due to the defects in development of the infundibulum and the posterior lobe. Our study thus reveals an essential role for Lhx2 in the regulation of posterior pituitary development and suggests a mechanism whereby development of the posterior lobe may affect the development of the anterior and intermediate lobes of the pituitary gland

    Drosophila type IV collagen mutation associates with immune system activation and intestinal dysfunction

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    This thesis introduces and explores a new type of representation for low and medium level vision operations called channel representation. The channel representation is a more general way to represent information than e.g. as numerical values, since it allows incorporation of uncertainty, and simultaneous representation of several hypotheses. More importantly it also allows the representation of “no information” when no statement can be given. A channel representation of a scalar value is a vector of channel values, which are generated by passing the original scalar value through a set of kernel functions. The resultant representation is sparse and monopolar. The word sparse signifies that information is not necessarily present in all channels. On the contrary, most channel values will be zero. The word monopolar signifies that all channel values have the same sign, e.g. they are either positive or zero. A zero channel value denotes “no information”, and for non-zero values, the magnitude signifies the relevance. In the thesis, a framework for channel encoding and local decoding of scalar values is presented. Averaging in the channel representation is identified as a regularised sampling of a probability density function. A subsequent decoding is thus a mode estimation technique.' The mode estimation property of channel averaging is exploited in the channel smoothing technique for image noise removal. We introduce an improvement to channel smoothing, called alpha synthesis, which deals with the problem of jagged edges present in the original method. Channel smoothing with alpha synthesis is compared to mean-shift filtering, bilateral filtering, median filtering, and normalized averaging with favourable results. A fast and robust blob-feature extraction method for vector fields is developed. The method is also extended to cluster constant slopes instead of constant regions. The method is intended for view-based object recognition and wide baseline matching. It is demonstrated on a wide baseline matching problem. A sparse scale-space representation of lines and edges is implemented and described. The representation keeps line and edge statements separate, and ensures that they are localised by inhibition from coarser scales. The result is however still locally continuous, in contrast to non-max-suppression approaches, which introduce a binary threshold. The channel representation is well suited to learning, which is demonstrated by applying it in an associative network. An analysis of representational properties of associative networks using the channel representation is made. Finally, a reactive system design using the channel representation is proposed. The system is similar in idea to recursive Bayesian techniques using particle filters, but the present formulation allows learning using the associative networks

    Molecular Background of Toxic-Substances-Induced Morphological Alterations in the Umbilical Cord Vessels and Fetal Red Blood Cells

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    The relationship between smoking and human health has been investigated mostly in adults, despite the fact that the chemicals originating from sustained maternal smoking disrupt the carefully orchestrated regulatory cascades in the developing fetus. In this study, we followed molecular alterations in the umbilical cord (UC) vessels and fetal red blood cells (RBCs), which faithfully reflect the in vivo status of the fetus. We showed evidence for the decreased level of DNA-PKcs-positive nuclei in samples with smoking origin, which is associated with the impaired DNA repair system. Furthermore, we pointed out the altered ratio of MMP-9 metalloproteinase and its endogenous inhibitor TIMP-1, which might be a possible explanation for the morphological abnormalities in the UC vessels. The presented in vivo dataset emphasizes the higher vulnerability of the veins, as the primary target for the toxic materials unfiltered by the placenta. All these events become amplified by the functionally impaired fetal RBC population via a crosstalk mechanism between the vessel endothelium and the circulating RBCs. In our ex vivo approach, we looked for the molecular explanation of metal-exposure-induced alterations, where expressions of the selected genes were upregulated in the control group, while samples with smoking origin showed a lack of response, indicative of prior long-term in utero exposure
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