31 research outputs found

    Analysis with monoclonal antibodies of human lymphoid cells forming rosettes with rabbit red blood cells.

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    Rabbit red blood cells have previously been shown to rosette with a subpopulation of thymocytes and with mitogen activated peripheral lymphocytes but not with unstimulated lymphocytes. Using monoclonal antibodies and double marker assays we studied the phenotype of these cells. In thymus, over 90% of rosetting cells express antigens of immature thymocytes (HTA1, OKT6). A proportion of the rosetting cells shows in addition antigens of mature thymocytes (OKT3, UCHT1). These cells probably correspond to a stage of intrathymic maturation between common and mature thymocytes. Virtually all rosetting cells are T cells and express an antigen related to T cell activation (TAC) when lymphocytes are activated by mitogens like PHA or Con A. Few rosetting cells are Ia positive. Two other antigens (OKT9, OKT10) known to be associated with proliferating and immature cells, are found in variable proportions on rosetting cells. After stimulation with allogeneic lymphocytes, fewer rosettes are detected than after stimulation by mitogens. Cells activated by a soluble antigen (PPD) and forming rosettes with rabbit red blood cells have a helper phenotype (Leu3a positive). Screening of leukaemia cell samples revealed that only cells from patients with T-ALL form rosettes with rabbit red blood cells. Rosette formation is almost totally inhibited by a polyclonal anti-thymocyte serum and two monoclonal antibodies (OKT11A,Lyt3) which have been shown to block rosettes with sheep erythrocytes

    Maternal Factors that Induce Epigenetic Changes Contribute to Neurological Disorders in Offspring

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    It is well established that the regulation of epigenetic factors, including chromatic reorganization, histone modifications, DNA methylation, and miRNA regulation, is critical for the normal development and functioning of the human brain. There are a number of maternal factors influencing epigenetic pathways such as lifestyle, including diet, alcohol consumption, and smoking, as well as age and infections (viral or bacterial). Genetic and metabolic alterations such as obesity, gestational diabetes mellitus (GDM), and thyroidism alter epigenetic mechanisms, thereby contributing to neurodevelopmental disorders (NDs) such as embryonic neural tube defects (NTDs), autism, Down’s syndrome, Rett syndrome, and later onset of neuropsychological deficits. This review comprehensively describes the recent findings in the epigenetic landscape contributing to altered molecular profiles resulting in NDs. Furthermore, we will discuss potential avenues for future research to identify diagnostic markers and therapeutic epi-drugs to reverse these abnormalities in the brain as epigenetic marks are plastic and reversible in nature

    Process development in a miniplant scale - A multilevel - multiscale PSE approach for developing an improved Oxidative Coupling of Methane process

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    The oxidative coupling of methane (OCM) is a promising alternative route to olefins that converts methane to higher hydrocarbons and open up a new feedstock for the oil based industry. However, due to yield limitations of available catalysts and high separation costs for conventional gas processing, the OCM process has not been applied yet in the industry. Starting with process simulation and sensitivity studies a flexible mini-plant was built in this research so as to demonstrate technical feasibility of an efficient OCM process, model validity and to study long term effects. By this means a concurrent engineering approach was applied for the whole process while investigating each unit parallel. Moreover, catalyst with several reactor concepts like the fluidized bed and membrane reactor were investigated by CFD simulation, process simulation and experiments, in order to study catalyst life time, operation conditions and technical feasibility. Thus, the reaction section was improved from 16% yield to 18%. Furthermore, the separation part of the OCM process was energetically improved by an integrated down streaming unit for the CO2. Thus, an energetic improvement of more than 40% in comparison to a benchmark absorption - desorption based CO2 separation process was achieved. In addition to this, novel absorbents were studied starting with molecular simulation up to process simulation and experimental validation for the CO2 separation. The results of the integrated process development and optimization process for the OCM will be presented and an overview of the multi scale and multilevel Process System Engineering (PSE) approach will be given for the case study

    The effect of genotype and in utero environment on interindividual variation in neonate DNA methylomes

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    Integrating the genotype with epigenetic marks holds the promise of better understanding the biology that underlies the complex interactions of inherited and environmental components that define the developmental origins of a range of disorders. The quality of the in utero environment significantly influences health over the lifecourse. Epigenetics, and in particular DNA methylation marks, have been postulated as a mechanism for the enduring effects of the prenatal environment. Accordingly, neonate methylomes contain molecular memory of the individual in utero experience. However, interindividual variation in methylation can also be a consequence of DNA sequence polymorphisms that result in methylation quantitative trait loci (methQTLs) and, potentially, the interaction between fixed genetic variation and environmental influences. We surveyed the genotypes and DNA methylomes of 237 neonates and found 1423 punctuate regions of the methylome that were highly variable across individuals, termed variably methylated regions (VMRs), against a backdrop of homogeneity. MethQTLs were readily detected in neonatal methylomes, and genotype alone best explained ?25% of the VMRs. We found that the best explanation for 75% of VMRs was the interaction of genotype with different in utero environments, including maternal smoking, maternal depression, maternal BMI, infant birth weight, gestational age, and birth order. Our study sheds new light on the complex relationship between biological inheritance as represented by genotype and individual prenatal experience and suggests the importance of considering both fixed genetic variation and environmental factors in interpreting epigenetic variation

    Transcriptome changes affecting Hedgehog and cytokine signalling in the umbilical cord: implications for disease risk

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    BACKGROUND: Babies born at lower gestational ages or smaller birthweights have a greater risk of poorer health in later life. Both the causes of these sub-optimal birth outcomes and the mechanism by which the effects are transmitted over decades are the subject of extensive study. We investigated whether a transcriptomic signature of either birthweight or gestational age could be detected in umbilical cord RNA.METHODS: The gene expression patterns of 32 umbilical cords from Singaporean babies of Chinese ethnicity across a range of birthweights (1698-4151 g) and gestational ages (35-41 weeks) were determined. We confirmed the differential expression pattern by gestational age for 12 genes in a series of 127 umbilical cords of Chinese, Malay and Indian ethnicity.RESULTS: We found that the transcriptome is substantially influenced by gestational age; but less so by birthweight. We show that some of the expression changes dependent on gestational age are enriched in signal transduction pathways, such as Hedgehog and in genes with roles in cytokine signalling and angiogenesis. We show that some of the gene expression changes we report are reflected in the epigenome.CONCLUSIONS: We studied the umbilical cord which is peripheral to disease susceptible tissues. The results suggest that soma-wide transcriptome changes, preserved at the epigenetic level, may be a mechanism whereby birth outcomes are linked to the risk of adult metabolic and arthritic disease and suggest that greater attention be given to the association between premature birth and later disease risk
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