214 research outputs found

    Ion-sensing using chemically-modified ISFETs

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    Synthetic macrocyclic polyether ion receptors are the active components for the selective and sensitive detection of potassium ions in chemical sensors based on modified ISFETs.\ud \ud Covalent chemical anchoring of the sensing membrane to the gate oxide of the ISFET is essential in order to increase the lifetime of the sensor system to more than three months

    Catalyst system based on polymer compounds comprising silasesquioxane-metal complexes

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    Catalyst systems based on a polymer compound having a molecular weight Mn of greater than 1000 g/mol, and comprising at least one silasesquioxane-metal complex, especially useful for the oxidation and oximation of organic compounds using peroxides; processes for preparation of such catalytic systems; and processes for use of such catalytic systems

    Oligomeric silasesquioxanes and a process for preparing oligomeric silasesquioxanes

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    Oligomeric silasesquioxanes having the formula R6Si6O9 wherein R is alkyl, cycloalkyl other than cyclohexyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, and/or heteroaryl, and the structure I; processes for preparing oligomeric silasesquioxanes of formula R6Si6O9 wherein R is alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, and/or heteroaryl; processes of using such oligomeric silasesquioxanes; and products obtained thereby

    Analysis of time-profiles with in-beam PET monitoring in charged particle therapy

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    Background: Treatment verification with PET imaging in charged particle therapy is conventionally done by comparing measurements of spatial distributions with Monte Carlo (MC) predictions. However, decay curves can provide additional independent information about the treatment and the irradiated tissue. Most studies performed so far focus on long time intervals. Here we investigate the reliability of MC predictions of space and time (decay rate) profiles shortly after irradiation, and we show how the decay rates can give an indication about the elements of which the phantom is made up. Methods and Materials: Various phantoms were irradiated in clinical and near-clinical conditions at the Cyclotron Centre of the Bronowice proton therapy centre. PET data were acquired with a planar 16x16 cm2^2 PET system. MC simulations of particle interactions and photon propagation in the phantoms were performed using the FLUKA code. The analysis included a comparison between experimental data and MC simulations of space and time profiles, as well as a fitting procedure to obtain the various isotope contributions in the phantoms. Results and conclusions: There was a good agreement between data and MC predictions in 1-dimensional space and decay rate distributions. The fractions of 11^{11}C, 15^{15}O and 10^{10}C that were obtained by fitting the decay rates with multiple simple exponentials generally agreed well with the MC expectations. We found a small excess of 10^{10}C in data compared to what was predicted in MC, which was clear especially in the PE phantom.Comment: 9 pages, 5 figures, 1 table. Proceedings of the 20th International Workshop on Radiation Imaging Detectors (iWorid2018), 24-28 June 2018, Sundsvall, Swede

    Effect of three common SNPs in 5′-flanking region of LEP and ADIPOQ genes on their expression in Polish obese children and adolescents

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    Genes encoding adipokines are considered as candidates for human obesity. In this study we analyzed the expression of leptin (LEP) and adiponectin (ADIPOQ) genes in relation to common 5′-flanking or 5′UTR variants: -2548G>A (LEP), 19A>G (LEP) and -11377C>G (ADIPOQ) in Polish obese children and adolescents. Relative transcription levels in the subcutaneous adipose tissue (real time RT–PCR) and serum protein concentrations (RIA) were measured in 48 obese subjects with known genotypes at three polymorphic sites and in five non-obese controls. None of the studied polymorphisms altered significantly the expression. Significantly elevated relative transcription levels of the LEP gene (P < 0.05) and serum leptin concentrations (P < 0.01) were recorded in obese patients, when compared with the non-obese controls, but such differences were not found for the ADIPOQ gene. Interestingly, the leptin to adiponectin protein concentration ratio (L/A) was approximately sevenfold higher in obese children and adolescents when compared with the non-obese controls (P < 0.001). Taking into consideration the observed relationship between the genotypes and the gene expression level we suggest that these SNPs are not conclusive markers for predisposition to obesity in Polish children and adolescents. On the other hand, we confirmed that the leptin to adiponectin gene expression ratio (L/A) is an informative index characterizing obesity

    Epithelial cell integrin beta1 is required for developmental angiogenesis in the pituitary gland

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    As a key component of the vertebrate neuroendocrine system, the pituitary gland relies on the progressive and coordinated development of distinct hormone-producing cell types and an invading vascular network. The molecular mechanisms that drive formation of the pituitary vasculature, which is necessary for regulated synthesis and secretion of hormones that maintain homeostasis, metabolism, and endocrine function, remain poorly understood. Here, we report that expression of integrin beta1 in embryonic pituitary epithelial cells is required for angiogenesis in the developing mouse pituitary gland. Deletion of pituitary epithelial integrin beta1 before the onset of angiogenesis resulted in failure of invading endothelial cells to recruit pericytes efficiently, whereas deletion later in embryogenesis led to decreased vascular density and lumen formation. In both cases, lack of epithelial integrin beta1 was associated with a complete absence of vasculature in the pituitary gland at birth. Within pituitary epithelial cells, integrin beta1 directs a large transcriptional program that includes components of the extracellular matrix and associated signaling factors that are linked to the observed non-cell-autonomous effects on angiogenesis. We conclude that epithelial integrin beta1 functions as a critical and canonical regulator of developmental angiogenesis in the pituitary gland, thus providing insight into the long-standing systems biology conundrum of how vascular invasion is coordinated with tissue development

    Difference in expression between AQP1 and AQP5 in porcine endometrium and myometrium in response to steroid hormones, oxytocin, arachidonic acid, forskolin and cAMP during the mid-luteal phase of the estrous cycle and luteolysis

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    BACKGROUND: Recently, we demonstrated in vitro that AQP1 and AQP5 in the porcine uterus are regulated by steroid hormones (P4, E2), arachidonic acid (AA), forskolin (FSK) and cAMP during the estrous cycle. However, the potential of the porcine separated uterine tissues, the endometrium and myometrium, to express these AQPs remains unknown. Thus, in this study, the responses of AQP1 and AQP5 to P4, E2 oxytocin (OT), AA, FSK and cAMP in the porcine endometrium and myometrium were examined during the mid-luteal phase of the estrous cycle and luteolysis.METHODS: Real-time PCR and western blot analysis.RESULTS: Progesterone up-regulated the expression of AQP1/AQP5 mRNAs and proteins in the endometrium and myometrium, especially during luteolysis. Similarly, E2 also stimulated the expression of both AQPs, but only in the endometrium. AA led to the upregulation of AQP1/AQP5 in the endometrium during luteolysis. In turn, OT increased the expression of AQP1/AQP5 mRNAs and proteins in the myometrium during mid-luteal phase. Moreover, a stimulatory effect of forskolin and cAMP on the expression of AQP1/AQP5 mRNAs and proteins in the endometrium and myometrium dominated during luteolysis, but during the mid-luteal phase their influence on the expression of these AQPs was differentiated depending on the type of tissue and the incubation duration.CONCLUSIONS: These results seem to indicate that uterine tissues; endometrium and myometrium, exhibit their own AQP expression profiles in response to examined factors. Moreover, the responses of AQP1/AQP5 at mRNA and protein levels to the studied factors in the endometrium and myometrium are more pronounced during luteolysis. This suggests that the above effects of the studied factors are connected with morphological and physiological changes taking place in the pig uterus during the estrous cycle.</p

    T-cell number and subtype influence the disease course of primary chronic lymphocytic leukaemia xenografts in alymphoid mice.

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    Chronic lymphocytic leukaemia (CLL) cells require microenvironmental support for their proliferation. This can be recapitulated in highly immunocompromised hosts in the presence of T cells and other supporting cells. Current primary CLL xenograft models suffer from limited duration of tumour cell engraftment coupled with gradual T-cell outgrowth. Thus, a greater understanding of the interaction between CLL and T cells could improve their utility. In this study, using two distinct mouse xenograft models, we investigated whether xenografts recapitulate CLL biology, including natural environmental interactions with B-cell receptors and T cells, and whether manipulation of autologous T cells can expand the duration of CLL engraftment. We observed that primary CLL xenografts recapitulated both the tumour phenotype and T-cell repertoire observed in patients and that engraftment was significantly shorter for progressive tumours. A reduction in the number of patient T cells that were injected into the mice to 2-5% of the initial number or specific depletion of CD8+ cells extended the limited xenograft duration of progressive cases to that characteristic of indolent disease. We conclude that manipulation of T cells can enhance current CLL xenograft models and thus expand their utility for investigation of tumour biology and pre-clinical drug assessment

    Targeting the Ataxia Telangiectasia Mutated-null Phenotype in Chronic Lymphocytic Leukemia with Pro-oxidants

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    Inactivation of the Ataxia Telangiectasia Mutated gene in chronic lymphocytic leukemia results in resistance to p53-dependent apoptosis and inferior responses to treatment with DNA damaging agents. Hence, p53-independent strategies are required to target Ataxia Telangiectasia Mutated-deficient chronic lymphocytic leukemia. As Ataxia Telangiectasia Mutated has been implicated in redox homeostasis, we investigated the effect of the Ataxia Telangiectasia Mutated-null chronic lymphocytic leukemia genotype on cellular responses to oxidative stress with a view to therapeutic targeting. We found that in comparison to Ataxia Telangiectasia Mutated-wild type chronic lymphocytic leukemia, pro-oxidant treatment of Ataxia Telangiectasia Mutated-null cells led to reduced binding of NF-E2 p45-related factor-2 to antioxidant response elements and thus decreased expression of target genes. Furthermore, Ataxia Telangiectasia Mutated-null chronic lymphocytic leukemia cells contained lower levels of antioxidants and elevated mitochondrial reactive oxygen species. Consequently, Ataxia Telangiectasia Mutated-null chronic lymphocytic leukemia, but not tumours with 11q deletion or TP53 mutations, exhibited differentially increased sensitivity to pro-oxidants both in vitro and in vivo. We found that cell death was mediated by a p53- and caspase-independent mechanism associated with apoptosis inducing factor activity. Together, these data suggest that defective redox-homeostasis represents an attractive therapeutic target for Ataxia Telangiectasia Mutated-null chronic lymphocytic leukemia

    Brain Iron and Metabolic Abnormalities in C19orf12 Mutation Carriers: A 7.0 Tesla MRI Study in Mitochondrial Membrane Protein–Associated Neurodegeneration

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    Background Mitochondrial membrane protein‐associated neurodegeneration is an autosomal‐recessive disorder caused by C19orf12 mutations and characterized by iron deposits in the basal ganglia. Objectives The aim of this study was to quantify iron concentrations in deep gray matter structures using quantitative susceptibility mapping MRI and to characterize metabolic abnormalities in the pyramidal pathway using 1H MR spectroscopy in clinically manifesting membrane protein‐associated neurodegeneration patients and asymptomatic C19orf12 gene mutation heterozygous carriers. Methods We present data of 4 clinically affected membrane protein‐associated neurodegeneration patients (mean age: 21.0 ± 2.9 years) and 9 heterozygous gene mutation carriers (mean age: 50.4 ± 9.8 years), compared to age‐matched healthy controls. MRI assessments were performed on a 7.0 Tesla whole‐body system, consisting of whole‐brain gradient‐echo scans and short echo time, single‐volume MR spectroscopy in the white matter of the precentral/postcentral gyrus. Quantitative susceptibility mapping, a surrogate marker for iron concentration, was performed using a state‐of‐the‐art multiscale dipole inversion approach with focus on the globus pallidus, thalamus, putamen, caudate nucleus, and SN. Results and Conclusion In membrane protein‐associated neurodegeneration patients, magnetic susceptibilities were 2 to 3 times higher in the globus pallidus (P = 0.02) and SN (P = 0.02) compared to controls. In addition, significantly higher magnetic susceptibility was observed in the caudate nucleus (P = 0.02). Non‐manifesting heterozygous mutation carriers exhibited significantly increased magnetic susceptibility (relative to controls) in the putamen (P = 0.003) and caudate nucleus (P = 0.001), which may be an endophenotypic marker of genetic heterozygosity. MR spectroscopy revealed significantly increased levels of glutamate, taurine, and the combined concentration of glutamate and glutamine in membrane protein‐associated neurodegeneration, which may be a correlate of corticospinal pathway dysfunction frequently observed in membrane protein‐associated neurodegeneration patients
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