177,151 research outputs found
Induction of placental macrophage migration inhibitory factor (MIF) by low oxygen environment
No full textRole of Macrophage Migration Inhibitory factor (MIF) on trophoblast growth and proliferation
No full textThe environmental chemical Bisphenol-A interferes with the action of 17 β-estradiol in human trophoblast
No full textProblem: normal placental development is a fundamental process for pregnancy success and foetal health. We recently demonstrated that environment polluting chemicals can affect this process. In the present study we investigated the potential of these chemicals to interfere with the hormone-action thus, acting as endocrine disruptors. Specifically we studied the effect of bisphenol-A (BPA), an estrogen-like chemical largely used in polycarbonate plastics and epoxy resins.
Methods: trophoblast-like BeWo cell lines and primary cultures of chorionic villous explants from human placenta were exposed to 17 β-estradiol (E2) and BPA alone or to their combination for 24, 48 and 72 hours. Cells and tissues were analyzed for human beta-Chorionic Gonadotropin, β-hCG production.
Results: the results showed that BPA interferes with the action of the endogenous hormone E2 mainly reducing β-hCG secretion at E2 concentrations ranging from 1 nM - 1 pM corresponding to those occurring in the maternal blood in the early stages of pregnancy.
Conclusions: these findings highlight marked effects of BPA on trophoblast cell endocrine function and raise concern about the negative, potential effects on mammalian females during early pregnancy
Comparison of serum thyroid microsomal and thyroid peroxidase autoantibodies in thyroid diseases
No full textRecent evidence indicates that human thyroid peroxidase (TPO) has most of the characteristics of the thyroid microsomal antigen. The question of whether TPO accounts for part or all of the antigenic activity recognized by circulating anti-microsomal antigen autoantibody (anti-M Ab) remains to be determined. The availability of an anti-TPO monoclonal antibody and of a highly purified TPO preparation allowed the development of specific and sensitive radioassays for anti-TPO autoantibody (anti-TPO Ab). In this study we compared anti-M Ab and anti-TPO Ab levels in serum from 128 subjects, including patients with Hashimoto's thyroiditis (n = 31), idiopathic myxedema (n = 11), hyperthyroid Graves' disease (n = 45), miscellaneous nonautoimmune thyroid disorders (n = 9), and normal subjects (n = 32). Anti-M Ab and anti-TPO Ab were measured by radioimmunological methods employing two different assay designs: 1) competitive radioassay (CR), based on the inhibition of radioiodinated antibody binding to human thyroid microsomes coated on microtiter wells, using a) [125I]immunoglobulin G (IgG) containing a high anti-M Ab titer (for anti-M Ab determinations), or b) [125I]anti-TPO monoclonal antibody (for anti-TPO Ab); and 2) sandwich immunoradiometric assay (IRMA) using microtiter wells coated with thyroid microsomes (for anti-M Ab determinations) or immunoaffinity-purified TPO (for anti-TPO Ab determinations) and [125I]anti-human IgG antibody. Anti-M Ab also was measured by passive hemagglutination. Anti-M Ab titers by PH closely correlated with anti-TPO Ab levels whether assayed by IRMA (r = 0.905; P less than 0.00001) or CR (r = 0.922; P less than 0.00001). Even closer correlations were found when anti-M Ab and anti-TPO Ab both were measured by the same type of radioassay procedure (IRMA, r = 0.945 and P less than 0.00001; CR, r = 0.957 and P less than 0.00001). No differences in the correlation between anti-M Ab and anti-TPO Ab results were found when the data in patients with different autoimmune thyroid disorders were analyzed separately. Further and more direct evidence for the identity of anti-M Ab and anti-TPO Ab was provided by the ability of purified TPO to completely inhibit the binding to thyroid microsomes of radioiodinated IgG preparations containing high anti-M Ab titers. In conclusion, our results provide strong support for the concept that TPO accounts for virtually all of the antigenic determinants reacting with the autoantibodies commonly termed anti-M antibodies
Hormone-like chemicals-cytokine interaction in the human chorionic villous explants
No full textProblem: hormones and cytokines acting locally at the maternal fetal interface are believed to play a major role in establishing the immune privilege of pregnancy. Numerous studies show that environment polluting chemicals can interfere with the action of natural hormones and therefore with the secretion of cytokines. In this study we investigated the effect of para-nonylphenol (p-NP), an environmental chemical with estrogenic activity as well as 17-Estradiol (E2) on human chorionic villous explants. Specifically we investigated the role of p-NP and E2 on the secretion of MIF (Macrophage Migration Inhibitory Factor), a cytokine highly present in placental tissues mainly in the early stages of pregnancy.
Methods: chorionic villous explants from first trimester human placenta were exposed to E2 or p-NP for 48 hours and then, analysed for MIF expression and its secretion in the culture medium. The membrane transporter, ATP binding cassette transporter A1 (ABCA1) was also investigated for its activity in MIF secretion.
Results: the results showed that both, p-NP and E2, significantly reduced MIF release by reducing the expression of ABCA1. Activity of p-NP was however much more potent than that of E2 since producing the same effect at much lower concentration, 1 nM (p-NP ) vs 10 mM (E2). No changes were observed in tissue MIF protein and mRNA content for any treatment
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
The macrophage migration inhibitory factor (MIF) is a regulator of trophoblast growth and differentiation
No full text"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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