1,720,969 research outputs found
Tadalafil in Primary Pulmonary Arterial Hypertension
No full textBackground: Sildenafil, a short-acting phosphodiesterase-5 inhibitor (1), is safe and may benefit patients with primary pulmonary arterial hypertension (2– 8). However, it requires many daily administrations. We describe a patient with end-stage primary pulmonary arterial hypertension who improved while taking tadalafil, a long-acting phosphodiesterase-5 inhibitor (9).
Case Report: A 72-year-old woman was hospitalized for progressive cardiopulmonary failure. Five years earlier, primary pulmonary arterial hypertension was diagnosed and the patient was hospitalized for hydropic decompensation and hypoxemia. Since then, she had
been receiving permanent oxygen therapy and had also taken digoxin, amlodipine, furosemide, potassium canrenoate, and acenocoumarol.
At the most recent hospitalization, the patient had dyspnea
(New York Heart Association class IV) and 4 pitting edema of the
legs up to the thighs, which had progressed over the previous 3
months. The patient’s blood pressure was 110/70 mm Hg, her pulse
was 102 beats/min, her respiratory frequency was 32 breaths/min,
and her temperature was 36.8 °C. During oxygen therapy (fraction
of inspired oxygen, 35%), arterial PO2 was 55 mm Hg. Electrocardiography
showed sinus rhythm and right ventricular hypertrophy.
Chest radiography showed cardiomegaly without signs of pulmonary
edema. Doppler echocardiography showed dilation of right chambers
with severe tricuspidal regurgitation and estimated peak systolic pulmonary
pressure of 105 mm Hg. Chest spiral computed tomography
excluded pulmonary arterial embolism.
Despite administration of intravenous diuretics and optimization
of oxygen therapy, the patient’s condition did not substantially
improve. Epoprostenol therapy was attempted but was stopped because
the patient had symptomatic arterial hypotension despite a low
infusion rate. Therefore, with the patient’s informed consent, we
administered tadalafil (20 mg orally every other day) in addition to
background therapy.
After 2 weeks of tadalafil therapy, the patient improved remarkably
(New York Heart Association class III); the only untoward effect
was slight arterial hypotension that promptly regressed with amlodipine
withdrawal. Blood pressure was 116/66 mm Hg, pulse rate
was 84 beats/min, and respiratory frequency was 20 breaths/min. Leg
edema was remarkably reduced. The patient’s arterial PO2 was 70
mm Hg during oxygen therapy (fraction of inspired oxygen, 0.28%).
Doppler echocardiography showed a notable reduction of the estimated
peak systolic pulmonary pressure (80 mm Hg). Accordingly,
doses of intravenous diuretics were progressively decreased and were
administered orally. The patient was discharged and referred to outpatient
care.
After 6 months of tadalafil treatment, the patient’s functional
status improved (New York Heart Association class II to III). Physical
examination showed stable normotension, further reduction of
heart rate and respiratory frequency, and disappearance of leg edema.
Arterial PO2 during oxygen therapy (fraction of inspired oxygen,
0.24%) remained stably above 70 mm Hg. Doppler echocardiography
showed progressive reduction of estimated peak pulmonary systolic
pressure (up to 65 mm Hg). Accordingly, we reduced oral doses
of diuretics and prescribed oxygen therapy only during physical activity.
Table. Overall Effects of Low-Dose Steroids Based on Corticotropin Stimulation Testing Results
Outcome Nonresponders
(Events/Total Patients)
Responders
(Events/Total Patients)
Control Group,
% (n/n)
Steroid Group,
% (n/n)
P Value Control Group,
% (n/n)
Steroid Group,
% (n/n)
P Value
Death 63 (83/132) 51 (63/123) 0.05 57 (32/56) 49 (34/69) 0.2
Shock reversal 39 (48/123) 53 (63/118) 0.03 44 (20/45) 56 (30/54) 0.2
Letters
www.annals.org 2 November 2004 Annals of Internal Medicine Volume 141 • Number 9 743
Discussion: By stabilizing guanosine 3,5-cyclic monophosphate
in vascular smooth-muscle cells of the pulmonary artery, sildenafil
prolongs the effect of endogenous vasodilators. Through this mechanism,
it reduces mean pulmonary artery pressure and the pulmonary-
to-systemic vascular resistance ratio and improves the overall
ventilation–perfusion mismatch, arterial oxygenation, and functional
capacity (3– 8). However, because it has a half-life of about 4 hours
(1), sildenafil requires many daily administrations, which in the long
term may compromise treatment adherence and may be costly.
In our patient with end-stage primary pulmonary arterial hypertension,
we observed that long-term treatment with tadalafil, which
has a half-life of about 18 hours, was safe and greatly improved
pulmonary hemodynamics and arterial oxygenation (Figure). These
improvements were paralleled by a striking improvement in clinical
and functional status. Besides confirming the efficacy of phosphodiesterase-
5 inhibitors in treatment of primary pulmonary arterial hypertension,
this finding may alert physicians to the possibility that
tadalafil may be more affordable than sildenafil. In fact, because its
half-life is nearly 5-fold greater than sildenafil’s (9), tadalafil may be
administered once daily or even every second day, a feature that may
improve adherence and reduce treatment costs
Long term combination treatment for severe idiopathic pulmonary arterial hypertension.
No full textWe report the long-term follow-up of 3 cases of severe idiopathic pulmonary arterial hypertension, in whom tadalafil plus sitaxentan combination therapy improved the clinical condition and exercise performance without any relevant adverse event
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
Valutazione della risposta bronchiale alla metacolina in pazienti asmatici ASA-sensibili
No full text
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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