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Quantitative analysis of changes occurring in muscle vastus lateralis in patients with heart failure after low-intensity training.
No full textOBJECTIVE: To quantitate the changes occurring in muscle vastus lateralis after exercise training of low intensity adopted for the rehabilitation of patients with chronic heart failure.
STUDY DESIGN: Nine consecutive males with a clinical diagnosis of idiopathic dilated and ischemic cardiomyopathy underwent an eight-week period of training. The intensity of the work was calculated as 40% of peak VO2. The program consisted of 30 minutes of cycling three times per week. A cardiopulmonary exercise test, hemodynamic measurements and echocardiographic studies were carried out. Needle biopsies were taken from muscle vastus lateralis before starting and after completing training. Quantitative analysis was carried out on sections stained with ATPase at pH 9.5 for measurement of the lesser diameter of type 1 and 2 fibers (by using an image analyzer) and on UEA 1-stained sections for capillary density and capillary/fiber ratio (by using a frame in the eyepiece of the microscope). The Wilcoxon test was applied to identify significant differences before and after training. Spearman's rank correlation coefficient was also calculated to highlight any correlation between the morphologic data and results of clinical tests.
RESULTS: After completing the training program, all the patients experienced an improvement in exercise tolerance and a significant increase (P < .004) in the VO2 and VCO2 peak. Skeletal muscle showed a significant (P < .02) increase in the capillary/fiber ratio. The changes were not significantly correlated with any of the clinical findings.
CONCLUSION: Low-intensity training can improve the functional capacity of patients with heart failure while producing only mild morphologic changes in their muscles
Oxidative stress, endothelial function and coenzyme Q10.
No full textReactive oxygen species seem to play an important role in vascular homeostasis. In conditions of high oxidative stress, such as chronic heart failure and multiple coronary risk factors, the rate of inactivation of nitric oxide to peroxynitrite by superoxide anions may be reduced by CoQ10, which can also protect against nitrosative damage. CoQ10 may also influence vascular function indirectly via inhibition of oxidative damage to LDL. Patients with lower levels of extracellular superoxide dismutase (ecSOD) demonstrate greater improvements than patients with normal ec-SOD levels, suggesting that the higher the oxidative stress the greater the improvement in the endothelium-dependent relaxation after the administration of a compound with antioxidant properties like CoQ10. Future studies are needed to inquire whether these effects may translate into benefits in clinical practice
Coenzyme Q(10) , endothelial function, and cardiovascular disease.
No full textSince the time a precise role of coenzyme Q(10) (CoQ(10) ) in myocardial bioenergetics was established, the involvement of CoQ in the pathophysiology of heart failure was hypothesized. This provided the rationale for numerous clinical trials of CoQ(10) as adjunctive treatment for heart failure. A mild hypotensive effect of CoQ was reported in the early years of clinical use of this compound. We review early human and animal studies on the vascular effects of CoQ. We then focus on endothelial dysfunction in type 2 diabetes and the possible impact on this condition of antioxidants and nutritional supplements, and in particular the therapeutic effects of CoQ. The effect of CoQ(10) on endothelial dysfunction in ischemic heart disease is also reviewed together with recent data highlighting that treatment with CoQ(10) increases extracellular SOD activity
Coenzyme Q10 improves contractility of dysfunctional myocardium in chronic heart failure.
No full textThere is evidence that plasma CoQ(10) levels decrease in patients with advanced chronic heart failure (CHF).To investigate whether oral CoQ(10) supplementation could improve cardiocirculatory efficiency in patients with CHF.We studied 21 patients in NYHA class II and III (18M, 3W, mean age 59 +/- 9 years) with stable CHF secondary to ischemic heart disease (ejection fraction 37 +/- 7\%), using a double-blind, placebo-controlled cross-over design. Patients were assigned to oral CoQ(10) (100 mg tid) and to placebo for 4 weeks, respectively.CoQ(10) supplementation resulted in a threefold increase in plasma CoQ(10) level (P < 0.0001 vs placebo). Systolic wall thickening score index (SWTI) was improved both at rest and peak dobutamine stress echo after CoQ(10) supplementation (+12.1 and 15.6\%, respectively, P < 0.05 vs placebo). Left ventricular ejection fraction improved significantly also at peak dobutamine (15\% from study entry P < 0.0001) in relation to a decrease in LV end-systolic volume index (from 57 +/- 7 mL/m(2) to 45 mL/m(2), P < 0.001). Improvement in the contractile response was more evident among initially akinetic (+33\%) and hypokinetic (+25\%) segments than dyskinetic ones (+6\%). Improvement in SWTI was correlated with changes in plasma CoQ(10) levels (r = -0.52, P < 0.005). Peak VO(2) was also improved after CoQ(10) as compared with placebo (+13\%, <0.005). No side effects were reported with CoQ(10).Oral CoQ(10) improves LV contractility in CHF without any side effects. This improvement is associated with an enhanced functional capacity
Effect of coenzyme Q<sub>10</sub> administration on endothelial function and extracellular superoxide dismutase in patients with ischaemic heart disease: a double-blind, randomized controlled study
No full textAims: This randomized controlled study was designed to determine whether oral coenzyme Q10 (CoQ10) supplementation (100 mg tid) was able to improve extracellular superoxide dismutase (ecSOD) activity and endothelium-dependent (ED) vasodilation in patients with coronary artery disease (CAD). ecSOD, a major antioxidant enzyme system of the vessel wall, is reduced in patients with CAD. Moreover, there is a strong correlation between endothelium-bound ecSOD and the ED dilation of conduit arteries. CoQ10 has been recently shown to improve the ED relaxation in diabetic patients.
Methods and results: Thirty-eight CAD patients (33 M/5 F, mean age 55 ± 4 years, ejection fraction 57.5 ± 8%) were randomized into two groups. One group (n = 19) received CoQ10 orally at doses of 300 mg/day for 1 month, whereas the other group received a placebo. On entry and after 1 month, all patients underwent brachial artery ED assessment, cardiopulmonary exercise test, and the measurement of endothelium-bound ecSOD activity. A total of 33 patients completed the study. ecSOD, ED relaxation, as well as peak VO2 and O2 pulse increases in the CoQ10 -treated group were statistically greater vs. the variations in the placebo group. In particular, improvements elicited by CoQ10 supplementation were remarkable in subjects presenting low initial endothelium-bound ecSOD and thus more prone to oxidative stress.
Conclusion: Improvements in the ED relaxation and endothelium-bound ecSOD activity might be related to CoQ10 capability of enhancing endothelial functionality by counteracting nitric oxide oxidation. The enhancement of peak VO2 and of O2 pulse is likely due to the bioenergetic effect of CoQ10; on the other end, the improved VO2 could also depend on the observed enhanced peripheral endothelial function
Coenzyme Q10 and exercise training in chronic heart failure.
No full textThere is evidence that plasma coenzyme Q(10) (CoQ(10)) levels decrease in patients with advanced chronic heart failure (CHF). However, it is not known whether oral CoQ(10) supplementation may improve cardiocirculatory efficiency and endothelial function in patients with CHF.We studied 23 patients in NYHA class II and III (20 men, three women, mean age 59+/-9 years) with stable CHF secondary to ischaemic heart disease [ejection fraction 37+/-7\%], using a double-blind, placebo-controlled cross-over design. Patients were assigned to each of the following treatments: oral CoQ(10) (100 mg tid), CoQ(10) plus supervised exercise training (ET) (60\% of peak VO(2), five times a week), placebo, and placebo plus ET. Each phase lasted 4 weeks. Both peak VO(2) and endothelium-dependent dilation of the brachial artery (EDDBA) improved significantly after CoQ(10) and after ET as compared with placebo. CoQ(10) main effect was: peak VO(2)+9\%, EDDBA +38\%, systolic wall thickening score index (SWTI) -12\%; ET produced comparable effects. CoQ(10) supplementation resulted in a four-fold increase in plasma CoQ(10) level, whereas the combination with ET further increased it. No side effects were reported with CoQ(10).Oral CoQ(10) improves functional capacity, endothelial function, and LV contractility in CHF without any side effects. The combination of CoQ(10) and ET resulted in higher plasma CoQ(10) levels and more pronounced effects on all the abovementioned parameters. However, significant synergistic effect of CoQ(10) with ET was observed only for peak SWTI suggesting that ET amplifies the already described effect of CoQ(10) on contractility of dysfunctional myocardium
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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