1,720,963 research outputs found
Potential Contribution of Hypertension to Evolution of Chronic Migraine and Related Mechanisms
No full textAims: To investigate the potential contributions of diastolic and systolic blood pressure (BP) and the circadian rhythm of BP to chronic migraine evolution. Methods: This cross-sectional study included four groups of patients selected based on migraine frequency (high frequency ≥ 10 days per month and low frequency < 10) and on the presence of hypertension. Among-group and pairwise comparisons were carried out to investigate potential neurophysiologic differences in the cerebral vessel reactivity to a nitroglycerin test, in autonomic balance (tilting test), and BP circadian rhythm. Results: A more marked decrease in cerebral blood flow velocity was observed in hypertensive high-frequency migraineurs compared to all other groups (P = .037). Moreover, a smaller decrease in vagal tone was recorded in the orthostatic position in hypertensive subjects, whether they were high- (P = .032) or low-frequency migraineurs (P = .014), with a consistently higher vagal to sympathetic tone ratio (P = .033). Finally, in nonhypertensive subjects, a higher but not significant prevalence of systolic nondippers was detected in high-frequency migraineurs (67%) compared to low-frequency subjects (25%; P = .099). Conclusion: These findings suggest that hypertension may contribute to the chronic evolution of headache with mechanisms shared with migraine; ie, vascular tone alteration and autonomic dysregulation
Twenty-four-hour blood pressure profile, orthostatic hypotension, and cardiac dysautonomia in elderly type 2 diabetic hypertensive patients
No full textIn elderly hypertensive type 2 diabetics, a blunted nocturnal BP fall is associated with OH and autonomic dysfunction. These data suggest that ABPM should be performed in the assessment of hypertensive diabetic patients in whom the cardiovascular dysautonomia is suspected or the signs of it are present (such as OH)
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Ambulatory 24-h ECG monitoring and cardiovascular autonomic assessment for the screening of silent myocardial ischemia in elderly type 2 diabetic hypertensive patients
No full textThe aim of the study was to evaluate the usefulness of Holter monitoring for the detection of silent myocardial ischemia (SMI) in elderly type 2 diabetic patients with hypertension and the possible relationship between SMI and cardiovascular autonomic neuropathy (CAN). Two hundred and forty-three asymptomatic outpatients, aged 65-75 years, with type 2 diabetes and essential hypertension underwent 24-h ECG monitoring and 5 tests for the evaluation of both parasympathetic (heart rate variability, response to breath deeping, and Valsalva manoeuvre) and sympathetic (cold pressor test and orthostatic hypotension test) autonomic function. A total of 518 asymptomatic episodes of ST depression during Holter monitoring indicative of SMI were detected in 51 of the 243 studied patients (20.9 %). None of the patients with ST depression episodes exhibited a normal response to at least one of the evaluated autonomic function tests, whereas 22 of the 192 patients without ST changes (11.4 %) exhibited a normal response to all tests. Abnormality in both parasympathetic and sympathetic function test responses was found in 94.1 % of patients with ST depression episodes vs 26.1 % of those without ST changes (P < 0.001). Statistical evaluation of the relationship between the abnormal response to single autonomic function test and episodes of ST depression was highly significant for all the 5 tests (P < 0.001). These results indicate that: (a) Holter monitoring enables to detect ST segment changes indicative of SMI in 20.9 % of elderly diabetic patients with hypertension; (b) the presence of autonomic cardiac dysfunction in these patients suggests a role of diabetic neuropathy in the pathogenesis of SMI; an
Effect of Evening Bromazepam Administration on Blood Pressure and Heart Rate in Mild Hypertensive Patients
No full textAim: To assess the effects of chronic evening oral administration
of bromazepam alone or in combination with propranolol
on ambulatory blood pressure (BP) and heart rate (HR) in
mild hypertensive subjects. Methods: Thirty-seven mild hypertensive
patients after a 2-week placebo period were randomized
to bromazepam 3 mg, propranolol 40 mg, bromazepam
3 mg plus propranolol 40 mg or placebo for
2 weeks according to a double-blind, double dummy, crossover
design. After each treatment period, 24-h BP and HR
ambulatory monitoring was performed by using a non-invasive
device. Results: Ambulatory monitoring showed that
during night-time SBP and DBP values were unaffected by
bromazepam as compared to placebo, whereas SBP was significantly
reduced by propranolol both when taken alone
and in combination with bromazepam. HR nocturnal values
were significantly reduced by propranolol, whereas they
were significantly increased by bromazepan both when taken
alone (+11.5%, p < 0.05 vs. placebo) and in combination
with propranolol (+12.8%, p < 0.05 vs. propranolol). No significant
difference in day-time values of SBP, DBP and HR was
observed among the 4 treatment groups. Conclusions: In
mild hypertensive patients, evening consumption of bromazepam
for a 2-week period did not affect BP, while it increased
nocturnal HR. Such an increase was observed both
when bromazepam was taken alone and in combination
with propranolol, which suggests that it depends on a bromazepam
mediated decrease in vagal tone. Whatever the
mechanism, the HR nocturnal increase might be of clinical
relevance, due to the role of high HR as cardiovascular risk
factor, particularly in already at risk hypertensive subjects
Variations on the Author
Get PDF“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
Get PDFWe 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
Get PDFWe 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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