1,720,978 research outputs found
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
Organ-specific and non-organ-specific autoantibodies in children and young adults with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED)
No full textOBJECTIVE: The aim of the study was to assess the complex of autoantibodies which can be detected in patients with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED), a rare autosomal recessive disease in which the extent of autoimmunity is still unknown.
DESIGN: Antibodies (A) to parathyroid glands, adrenal cortex (AC-A), ovary and testis (steroid cell antibodies, SC-A), pancreatic islet cells (IC-A), gastric parietal cells, and non-organ-specific antigens were investigated in 11 APECED patients living in the Salento region of southern Italy. Further measurements included antibodies to cytochrome P450 (CYP) enzymes: cholesterol side-chain cleavage enzyme (CYP11A), 21-hydroxylase (CYP21) and 17alpha-hydroxylase (CYP17); and to glutamic acid decarboxylase 65-kDa isoform (GAD65), tyrosine phosphatase-like protein IA2, thyroglobulin (TG), thyroperoxidase (TPO), thyrotropin receptor, liver CYP enzymes and intrinsic factor.
METHODS: Antibodies to organs and subcellular fractions were detected by immunofluorescence. Radiobinding, immunoradiometric, and immunoblotting assays were used for the other measurements.
RESULTS: AC-A and SC-A were positive in all sera; among antibodies to adrenal CYP enzymes, only CYP21-A were present in all the patients with Addison's disease of short-medium duration (15 years), two tested positive for antibodies to all three CYP enzymes, and the other for only CYP11A-A. In all sera CYP11A-A and/or CYP17-A were found. Two patients tested positive for both IC-A and GAD65-A, one for both IC-A and IA2-A, and one for GAD65-A; the fasting C-peptide assay showed no statistical difference between these four subjects and the others. All four hypothyroid patients were positive for TPO-A, while two of them were positive and two were negative for TG-A; two euthyroid subjects had positivity for TG-A. Liver-kidney microsomal antibodies reacting against the CYP2A6 were detected in two patients with autoimmune hepatitis. All but one sera contained anti-nuclear antibodies at a titre ranging between 1:20 and 1:80; however, only two patients had a connective tissue disease (Sjögren's syndrome).
CONCLUSIONS: Several autoantibodies may be detected in any APECED patient. Our data confirm that CYP21-A and TPO-A are major autoantibodies involved in APECED-associated Addison's disease and hypothyroidism respectively, while CYP11A-A and CYP17-A correlate with positivity for SC-A. Markers of islet cell autoimmunity are frequent, but prevalence and modalities of progression to overt beta-cell failure have to be clarified. Low-titre non-organ-specific autoantibodies are a feature of autoimmunity in APECED, but their role has yet to be fully explained
A ROLE FOR LH IN ALDOSTERONE SECRETION: PRELIMINARY RESULTS OF AN IN VITRO STUDY ON CONN ADENOMAS AND NORMAL ADRENALS
No full textObjective: Recent studies identified overexpression of G-protein coupled receptors in adrenal adenomas, among which luteinizing hormone receptor (LHR). Clinically, its is known that plasma aldosterone levels may increase under LH stimulation, at least in females (Fommei, 2009). Aim of the study was to confirm LHR presence in aldosterone producing adenomas and assess the direct LH effect on aldosterone production in vitro, in a comparison with normal adrenals.
Design and Method: After informed consent, adrenal fragments were collected from 16 hypertensive patients (7F/9M, mean age 66 years) during laparoscopic unilateral adrenalectomy for clinically confirmed primary aldosteronism due to unilateral adenoma and from normal adrenal glands of 6 cadaveric kidney normotensive donors (3F/3M, mean age 59 years). LHR was assayed by Western blotting analysis. Adrenal cell cultures from 12 hypertensive patients were also obtained and cortisol levels in supernatant measured as a marker of cell viability.Cells were then splitted and investigated both in the absence or presence of LH (300 ng/ml) in serum free-DMEM/F12 medium for 6 h. The supernatant was then assayed for aldosterone levels (Aldoctk-2RIA, Diasorin, Italy).
Results: Western blotting analysis demonstrated LHR proteins as single bands at 85 kDa in all the explored adrenal tissues; however, LHR were more expressed in hypertensive patients than in normotensive kidney donors (1.71 ± 0.57 vs. 0.72 ± 0.21 mean ± SD of LHR/beta-actin; p < 0.001). LH stimulation of adrenal cells significantly increased aldosterone levels compared to unstimulated cultures in 5/12 patients, by a mean of 1.5 folds (p < 0.05).
Conclusion: The results confirm LHR presence in human adrenal cortex and demonstrate an increased expression in Conn adenomas compared to normal adrenals. They also suggest the presence of LH dependent mechanism(s) on aldosterone secretion at least in subsets of human hyperaldosteronism
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
Erythrocyte sodium pump stimulation by ouabain and an endogenous ouabain-like factor
No full textCardiac glycosides inhibit the sodium pump. However, some studies suggest that nanomolar ouabain concentrations can
stimulate the activity of the sodium pump.
In this study, using the Na
þ
/K
þ
-ATPase of human erythrocytes, we compared the effect of digoxin, ouabain and an ouabain
like-factor (OLF), on 86Rb uptake.
Ouabain concentrations below 10
9M significantly stimulate Rb
þ
uptake, and the maximal increase above base-line
values is 185% at 10
10M ouabain. No stimulation is observed in the same conditions by digoxin. OLF behaved like
ouabain, producing an activation of Rb
þ
flux at concentrations lower than 10
9Mouabain equivalents (143% at 10
10 M).
Western blot analysis revealed the presence of both a1 and a3 pump isoforms in human erythrocytes. Our data confirm the
analogies between OLF and ouabain and suggest that Na
þ
/K
þ
-ATPase activation may be related to the a3 isoform.
In addition, we investigated whether ouabain at different concentrations was effective in altering the intracellular calcium
concentration of erythrocytes. We found that ouabain at concentration lower than 10
9M did not affect this homeostasis
Triiodothyronine prevents cardiac ischemia/reperfusion mitochondrial impairment and cell loss by regulating miR30a/p53 axis.
No full text3,5,3'-Triiodothyronine deprivation affects phenotype and intracellular [Ca2+]i of human cardiomyocytes in culture
No full textOBJECTIVE:
A decrease in plasma T3 concentration is a frequent finding in patients with heart failure. However, the role of this 'low T3 syndrome' on disease evolution has never been clarified. As phenotypic and functional cardiomyocyte impairments are alterations that correlate with the failing myocardium, we studied the long-term effects of T3 deprivation on human cardiomyocyte structure and calcium handling.
METHODS:
Atrial cardiomyocytes and myocardial tissue were cultured with or without 3 nM T3. Microscopical examination of structural features was followed by analysis of alpha-sarcomeric actinin and sarcoplasmic reticulum calcium ATP-ase (SERCA-2) content. Calcium handling was studied by [Ca2+](i) imaging.
RESULTS:
When stimulated with cyclopiazonic acid, a SERCA-2 inhibitor, T3-deprived cardiomyocytes showed significantly faster (P=0.03) and more transient (P=0.04) increases in [Ca(2+)](i) than T3-supplemented cells. Moreover, in the T3-free cultures a significantly lower number of cells (P=0.003) responded to caffeine, a typical activator of sarcoplasmic reticulum Ca(2+)-release channel. T3-deprived cardiomyocytes also presented altered morphology with larger dimensions than T3-supplemented cells (P < 0.0001). Additionally, in T3-deprived samples alpha-sarcomeric actinin and SERCA-2 protein levels were reduced to 65.6 +/- 3% (P < 0.0001) and 74.1 +/- 4% (P=0.005), respectively, when compared with the T3-supplemented group.
CONCLUSIONS:
Our data show that human cardiomyocyte calcium handling and phenotype are strongly influenced by T3 suggesting important implications of the 'low T3 syndrome' on the progression of heart failure
Organ-specific and non-organ-specific autoantibodies in children and young adults with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED)
No full textObjective: The aim of the study was to assess the complex of autoantibodies which can be detected in patients with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED), a rare autosomal recessive disease in which the extent of autoimmunity is still unknown. Design: Antibodies (A) to parathyroid glands, adrenal cortex (AC-A), ovary and testis (steroid cell antibodies, SC-A), pancreatic islet cells (IC-A), gastric parietal cells, and non-organ-specific antigens were investigated in 11 APECED patients living in the Salento region of southern Italy. Further measurements included antibodies to cytochrome P450 (CYP) enzymes: cholesterol side-chain cleavage enzyme (CYP11A), 21-hydroxylase (CYP21) and 17α-hydroxylase (CYP17); and to glutamic acid decarboxylase 65-kDa isoform (GAD65), tyrosine phosphatase-like protein IA2, thyroglobulin (TG), thyroperoxidase (TPO), thyrotropin receptor, liver CYP enzymes and intrinsic factor. Methods: Antibodies to organs and subcellular fractions were detected by immunofluorescence. Radiobinding, immunoradiometric, and immunoblotting assays were used for the other measurements. Results: AC-A and SC-A were positive in all sera; among antibodies to adrenal CYP enzymes, only CYP21-A were present in all the patients with Addison's disease of short-medium duration (15 years), two tested positive for antibodies to all three CYP enzymes, and the other for only CYP11A-A. In all sera CYP11 A-A and/or CYP17-A were found. Two patients tested positive for both IC-A and GAD65-A, one for both IC-A and IA2-A, and one for GAD65-A; the fasting C-peptide assay showed no statistical difference between these four subjects and the others. All four hypothyroid patients were positive for TPO-A, while two of them were positive and two were negative for TG-A; two euthyroid subjects had positivity for TG-A. Liver-kidney microsomal antibodies reacting against the CYP2A6 were detected in two patients with autoimmune hepatitis. All but one sera contained anti-nuclear antibodies at a titre ranging between 1:20 and 1:80; however, only two patients had a connective tissue disease (Sjogren's syndrome). Conclusions: Several autoantibodies may be detected in any APECED patient. Our data confirm that CYP21-A and TPO-A are major autoantibodies involved in APECED-associated Addison's disease and hypothyroidism respectively, while CYP11A-A and CYP17-A correlate with positivity for SC-A. Markers of islet cell autoimmunity are frequent, but prevalence and modalities of progression to overt β-cell failure have to be clarified. Low-titre non-organ-specific autoantibodies are a feature of autoimmunity in APECED, but their role has yet to be fully explained
- …
