1,720,985 research outputs found
Effect of growth hormone (GH) on the immune system
No full textA growing body of evidence indicates a bi-directional relationship between the neuroendocrine system and immune functions. It is well known that lymphoid organs such the thymus, the spleen and peripheral blood produce growth hormone (GH) and GH receptor is expressed on different subpopulations of lymphocytes. Many in vitro and in animal studies demonstrate an important role of GH in immunoregulation. GH stimulates T and B cells proliferation and immunoglobulin synthesis, enhances the maturation of myeloid progenitor cells and is also able to modulate cytokine response. However, in humans GH deficiency (GHD) is not usually associated with immunodeficiency and only minor abnormalities of immune function have been reported, as compared to those observed in GHD animals. It is possible that in humans the GH produced locally in the immune system compensates for the lack of endocrine GH. In this review the main actions of GH on the immune system in vitro, in animal models and in humans are summarized
Effect of growth hormone therapy on the proinflammatory cytokine profile in growth hormone-deficient children.
No full textThe aim of the present study was to establish whether growth hormone (GH) treatment in vivo affects pro-inflammatory cytokine production by resting or in vitro, activated, cultured, peripheral blood mononuclear cells (PBMC) from children with complete growth hormone deficiency (GHD). We evaluated 11, pre-pubertal children (6 males and 5 females) with GHD, aged between 6 and 14 years, and 9, age- and sex-matched healthy subjects were studied as controls (CTRLs). Freshly isolated PBMC were cultured for 4 or 24 h in X-VIVO medium in the presence or absence of 0.01 mu g/mL lipopolysaccharide for the determination of TNF-alpha and IL-6 production; alternatively, cells were incubated 24 h in X-VIVO medium with or without 25 mu g/mL Concanavalin A for IFN-gamma production. Cytokines were measured in the cell supernatants by enzyme-linked immunosorbent assay kits. The results of the present study provide evidence that spontaneous and/or mitogen-induced, in vitro PBMC production of pro-inflammatory cytokines is lower in GHD children than in healthy, age-matched individuals (p<0.05 by the Mann-Whitney U-test). After 3 months of GH therapy, cytokine production was significantly (p<0.05 by the Wilcoxon test) increased, but was still lower than in healthy controls. It is reasonable to speculate that severe GH deficiency can cause alterations in the pro-inflammatory cytokine-induced immune response in humans, and that GH treatment can ameliorate this important immunological function
Secular trends in growth of African Pygmies and Bantu
No full textOBJECTIVE: The aim of this study was to investigate whether a secular trend in growth occurred during the last century in Pygmies from Cameroon (West Pygmies) and in Bantu rural farmers, the latter being studied to serve as controls.-DESIGN: The evolution in height of West Pygmies and Bantu farmers from 1911 to 2006 was evaluated using data from the literature as well as data gathered by our research team during an expedition to Cameroon in 2006. RESULTS: During the last century, no secular trend in west Pygmies is apparent, as height changed from 151 cm to 155 cm in males and from 143 cm to 146 cm in females. A small though significant (p=0.026), increment (about 2 cm) was observed only in female subjects during the last ten years. By contrast, Bantu heights show a significant change from 1943 to 2006 for both males (from 159 cm to 172 cm; p=0.025) and females (from 148 cm to 160 cm; p=0.029). CONCLUSIONS: Over the last century, the Bantu population exhibited a significant secular trend for height, whereas West Pygmies did not increase their linear growth. The lack of secular trend in Pygmies possibly suggests that their stature reflects adaptation to the forest lifestyle. We may hypothesize that not only environmental but epigenetic factors have also contributed to their growth potential
Relationship between thymulin and growth hormone secretion in healthy human neonates.
No full textThe relationship among circulating values of growth hormone (GH), thymulin, and zinc in 19 healthy human neonates at birth and at the 4th month of age, and in their respective mothers, was investigated. Cytofluorimetric analysis on some CD antigen markers was conducted on cord blood and peripheral blood mononuclear cells. Active thymulin and zinc plasma levels increased in newborns in comparison with their mothers. In neonates serum GH levels increased with a significant decline later. The expression of CD molecules from newborns at birth and from infants at the 4th month of age was inversely correlated with active thymulin, zinc, and GH levels, whereas CD4 antigen marker was positively correlated with the same parameters at the 4th month of life. A novel interrelationship among active thymulin, zinc, and GH exists from the early up to the late phase of newborn life, in which maternal zinc, via lactation, may be involved
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe 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
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