1,720,969 research outputs found
Antihypertensive effects of verapamil, captopril and their combination at rest and during dynamic exercise.
No full textIn order to investigate the antihypertensive effects of verapamil (CAS 52-53-9) and captopril (CAS 62571-86-2), administered alone or in combination therapy, the blood pressure and heart rate effects of these two drugs at rest and during dynamic exercise were evaluated in a double blind study in 30 moderate or severe essential hypertensive patients. After a 30-day placebo wash-out period, 15 patients (age 60.6 +/- 8.0 years, mean +/- SD) were allocated to verapamil sustained-release treatment (120 mg b.i.d. for the first month of therapy and 240 mg b.i.d. for the second one) and 15 patients (age 58.4 +/- 10.0 years) to captopril treatment (25 mg b.i.d. and 50 mg b.i.d. for the first and second month of therapy, respectively). At low dosage both verapamil and captopril significantly (p less than 0.001) and markedly reduced blood pressure values. Goal diastolic blood pressure of 90 mmHg was achieved in 40\% and 20\% of patients in the verapamil group and in the captopril group, respectively, at high dosage. In contrast to captopril, verapamil induced a significant and dose-dependent heart rate reduction and markedly attenuated the pressor and tachycardiac responses to dynamic exercise. The combination of verapamil 240 mg b.i.d. plus captopril 50 mg b.i.d. was then administered to patients, whose blood pressure was not satisfactorily controlled by monotherapy. This regimen allowed a better blood pressure control both at rest and during exercise than on monotherapy and induced a complete blood pressure normalization in 62\% of patients.(ABSTRACT TRUNCATED AT 250 WORDS
Hemodynamic interactions between diuretics and calcium antagonists in the treatment of hypertensive patients.
No full textTo investigate the hypotensive and hemodynamic effects of plain and extended-release (ER) formulations of felodipine added to a diuretic in the treatment of moderate essential hypertension, we studied 18 patients in a randomized, double-blind, cross-over study. Blood pressure (BP), heart rate (HR), hemodynamics (bioimpedance), foot volume (Archimedes' principle), and symptoms were evaluated after a 1-month placebo washout, after 1-month's treatment with a fixed combination of hydrochlorothiazide 50 mg plus amiloride 5 mg (HA), and then after felodipine 5 mg twice daily (F) or felodipine ER 10 mg daily (FER) (double-blind phase), each given for 2 weeks in a randomized sequence together with the diuretic. All measurements were performed at the end of the dosing interval. At baseline, supine SBP/DBP was 175.6 +/- 12.9/113.4 +/- 8.1 mmHg; HR was 77.3 +/- 7.0 beats/min; CO was 5.3 +/- 1.4 l/min; SVR was 2166 +/- 707 dynes sec. cm5, and foot volume was 433 +/- 195 ml (FV). HA induced a reduction (p less than 0.05) in BP; one patient had a DBP = 90 mmHg and was excluded from the combination study; eight patients had a DBP reduction of greater than or equal to 10 mmHg (responders), and their blood pressure was mainly reduced by a fall in SVR. HR, CO, and FV were unchanged. The addition of felodipine to a diuretic induced a further significant (p less than 0.001) reduction in BP with respect to HA alone, with no differences between F and FER. All patients had a DBP fall greater than 10 mmHg, which had no relationship to their response to the diuretic.(ABSTRACT TRUNCATED AT 250 WORDS
Treatment of hypertensive patients with ventricular arrhythmias: comparison and combination of beta-blocker and anti-arrhythmic therapy.
No full textThe effect of therapy with atenolol and tocainide, separately or in combination, was studied in 20 patients with hypertension and concomitant ventricular arrhythmias. Patients were given 400 mg tocainide, three times daily, 100 mg atenolol, once daily (plus 25 mg hydrochlorothiazide and 2.5 mg amiloride diuretics if required) and a combination of these treatments. Tocainide alone significantly reduced the incidence of ventricular arrhythmias without affecting atrial arrhythmias. It also controlled exercise-induced arrhythmias in 7/13 (54\%) patients. Atenolol significantly reduced atrial arrhythmias and had a good effect on exercise-induced arrhythmias (reduced in 75\% of patients), but it did not have a significant effect on ventricular arrhythmias. In 13 patients, despite normalization of blood pressure by atenolol, it was necessary to combine antihypertensive therapy (atenolol) with anti-arrhythmic therapy (tocainide) in order to reduce ventricular arrhythmias. All drugs were well tolerated. It is concluded that, in certain patients, specific anti-arrhythmic treatment may be necessary to control ventricular arrhythmias in hypertensive patients despite normalization of blood pressure by beta-blockers
Favourable interaction of calcium antagonist plus ACE inhibitor on cardiac haemodynamics in treating hypertension: Rest and effort evaluation
No full textThe aim of the study was to evaluate the effects of verapamil sustained release (SR) 240 mg, enalapril and their combination on blood pressure (BP) and cardiac haemodynamics at rest and during exercise in 20 patients with moderate essential hypertension (seven men and 13 women, mean age ± s.d. 53.7 ± 15.8 years). After a 4 week placebo run-in period, patients were randomly allocated to received verapamil SR 240 mg once daily or enalapril 20 mg once daily for 4 weeks in a double-blind fashion. Patients whose diastolic blood pressure (DBP) was still ≥ 95 mm Hg at the end of this period received verapamil SR plus enalapril for an additional 4 weeks. At the end of the placebo, single and combined treatment periods, resting and exercise (bicycle ergometry) haemodynamics were evaluated by radionuclide ventricular angiography (technetium-99m) and the following parameters were assessed: BP, heart rate, double product, systemic vascular resistances (SVR), cardiac output (CO), stroke volume (SV), ejection fraction (EF) mean ejection rate (mER) and peak filling rate (PFR). Both verapamil SR and enalapril monotherapies significantly reduced resting and exercise BP (P < 0.01), with a BP normalisation (DBP ≤ 95 mm Hg) of five of 10 and 4 of 10 patients respectively. A greater BP fall and a normalisation of 11 of 11 patients was obtained in non-responders to monotherapy, when treated with verapamil SR and enalapril (P < 0.01). Verapamil SR also reduced heart rate at rest and during exercise (-11.8% and -18.4%, respectively, P < 0.05). Double product was significantly reduced at rest and during exercise in the verapamil group (P < 0.01); enalapril alone and verapamil plus enalapril reduced double product only at rest (P < 0.01). Resting and exercise SVR significantly decreased in the verapamil, enalapril and combined treatment groups (rest -16%, -13% and -15%; exercise -19%, -18% and -15%, respectively, P < 0.01). Left ventricular function showed a trend towards improvement after monotherapies; CO, EF and mER significantly improved with the combined regimen. In conclusion, verapamil SR and enalapril in a once a day administration were effective in the treatment of moderate hypertension, their anti-hypertensive effect was associated with a significant reduction of SVR. A further BP reduction was obtained with the combination of the two drugs that induced a reduction of SVR with a good tolerability profile. The better BP reduction obtained with the combination of the two drugs was associated with an improvement of left ventricular function particularly during effort where, for any reduction in DBP, there was more improvement in SV and CO
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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