1,720,966 research outputs found
The cardiovascular system in growth hormone excess and growth hormone deficiency.
No full textThe clinical conditions associated with GH excess and GH deficiency (GHD) are known to be associated with an increased risk for the cardiovascular morbidity and mortality, suggesting that either an excess or a deficiency in GH and/or IGF-I is deleterious for cardiovascular system. In patients with acromegaly, chronic GH and IGF-I excess commonly causes a specific cardiomyopathy characterized by a concentric cardiac hypertrophy associated with diastolic dysfunction and, in later stages, with systolic dysfunction ending in heart failure if GH/IGF-I excess is not controlled. Abnormalities of cardiac rhythm and anomalies of cardiac valves can also occur. Moreover, the increased prevalence of cardiovascular risk factors, such as hypertension, diabetes mellitus, and insulin resistance, as well as dyslipidemia, confer an increased risk for vascular atherosclerosis. Successful control of the disease is accompanied by a decrease of the cardiac mass and improvement of cardiac function and an improvement in cardiovascular risk factors. In patients with hypopituitarism, GHD has been considered the underlying factor of the increased mortality when appropriate standard replacement of the pituitary hormones deficiencies is given. Either childhood-onset or adulthood-onset GHD are characterized by a cluster of abnormalities associated with an increased cardiovascular risk, including altered body composition, unfavorable lipid profile, insulin resistance, endothelial dysfunction and vascular atherosclerosis, a decrease in cardiac mass together with an impairment of systolic function mainly after exercise. Treatment with recombinant GH in patients with GHD is followed by an improvement of the cardiovascular risk factors and an increase in cardiac mass together with an improvement in cardiac performance. In conclusion, acromegaly and GHD are associated with an increased risk for cardiovascular morbidity and mortality, but the control of GH/IGF-I secretion reverses cardiovascular abnormalities and restores the normal life expectancy
A Reappraisal of Diagnosing GH Deficiency in Adults: Role of Gender, Age, Waist Circumference, and Body Mass Index
No full textBeginning to end:cardiocascular implications of growth hormone (GH) deficiency and GH therapy.
No full textBoth growth hormone (GH) and insulin-like growth factor I (IGF-I) are involved in heart development and in maintenance of cardiac structure and performance. Cardiovascular disease has been reported to reduce life expectancy in both GH deficiency (GHD) and GH excess. Patients with GHD suffer from a cluster of abnormalities associated with increased cardiovascular risk, including abnormal body composition, unfavorable lipid profile, increased fibrinogen and C-reactive protein levels, insulin resistance, early atherosclerosis and endothelial dysfunction, and impaired left ventricular (LV) performance (i.e., reduced diastolic filling and impaired response to peak exercise). Long-term GH replacement therapy reverses most of these abnormalities. More consistently, GH replacement reduces body fat and visceral adipose tissue, reduces low-density lipoprotein cholesterol and triglyceride levels, and improves endothelial function. GH replacement also reduces intima media thickness at major arteries and improves LV performance, but these results have been observed only in small series of patients treated on a short-term basis. This review discusses the roles of GHD and GH replacement therapy in the development of cardiovascular disease
Does a gender-related effect of growth hormone (GH) replacement exist on cardiovascular risk factors, cardiac morphology, and performance and atherosclerosis? Results of a two-year open, prospective study in young adult men and women with severe GH deficiency
No full textCONTEXT: GH secretion and response to GH replacement are gender-related. OBJECTIVE: The objective of this study was to investigate the effects of GH deficiency (GHD) and replacement on the cardiovascular system according to gender. DESIGN: The design was open and prospective. SETTING: The study was conducted at a university hospital. SUBJECTS: Subjects included 36 severe adult-onset GHD patients (18 men, 20 women, aged < 45 yr); 36 gender-, age-, and body mass index-matched healthy subjects served as controls. INTERVENTIONS: Subjects received GH replacement at a median dose of 6.5 microg/kg.d in men and 7.7 microg/kg.d in women for 2 yr. MAIN OUTCOME MEASURES: Homeostasis model assessment index, total to HDL cholesterol ratio, fibrinogen and C-reactive protein levels, left ventricular mass index, blood pressure, heart rate, diastolic filling, and systolic function at rest and at peak exercise and intima-media thickness (IMT) at common carotid arteries were measured. RESULTS: Basal prevalence and/or degree of insulin resistance, lipid alterations, compromised cardiac function, and IMT were similar in women and men. Diastolic dysfunction was more prevalent in men (61 vs. 25%, P = 0.036). After GH replacement, IGF-I levels normalized in all patients. Lipid profile, fibrinogen, and C-reactive protein levels normalized in all cases. The total to HDL ratio (P = 0.04) was higher in women than men. The homeostasis model assessment index persisted higher in GHD patients than controls and decreased only in GHD men (P = 0.017). Left ventricular mass index normalized during treatment in both women and men, abnormal diastolic function persisted in three women (P = 0.031), and abnormal systolic performance persisted in six women and one man (P = 0.13). IMT decreased similarly in women and men, persisting higher than in controls. Exercise performance normalized in all. CONCLUSIONS: Two-year GH replacement has similar beneficial effects on cardiac and exercise performance and atherosclerosis in women and men with severe GHD
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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