Diltiazem alone and combined with nitroglycerin: effect on normal and diseased human coronary arteries

The vasodilatory effect of diltiazem and nitroglycerin on the large epicardial coronary arteries was evaluated in 26 patients with coronary artery disease. The luminal area of a normal and a stenotic coronary artery was determined at rest, after intracoronary administration of diltiazem, during submaximal exercise as well as 5 min after 1·6 mg sublingual nitroglycerin using biplane quantitative coronary arteriography. Twelve patients with no pretreatment prior to the exercise test served as group 1 (controls) and 14 patients with intracoronary administration of 2 to 3 mg diltiazem prior to the exercise test as group 2. Normal vessel: In the control group luminal area increased significantly during exercise (+23%, P<0·01) and after sublingual administration of nitroglycerin (+40%, P<0·001). In group 2 luminal area increased after intracoronary administration of diltiazem (+19%, P<0·01), during bicycle exercise (+23%, P<0·001) and after sublingual administration of nitroglycerin (+39%, P<0·001). Stenotic vessel: In the control group luminal area decreased significantly (−29%, P<0·001) during bicycle exercise but increased after sublingual administration of nitroglycerin at the end of the exercise test (+12%, NS vs. rest). In group 2 intracoronary administration of diltiazem was associated with a mild increase in stenosis area (+11%, P<0·05). There was a further increase in stenosis area during bicycle exercise (+23%, P<0·001 vs. rest) and after sublingual nitroglycerin (+32%, P<0·001). Coronary vasodilation of the stenotic segment was, however, significantly more pronounced after sublingual nitroglycerin in group 2 than 1 (+32% versus 12%, P<0·05). Thus, it is concluded that diltiazem prevents exercise-induced coronary vasoconstriction of the stenotic vessel segment probably due to its direct vasorelaxing action on the smooth vasculature. Diltiazem combined with nitroglycerin elicits an additive effect on coronary vasodilation of the stenotic vessel segments but not on the normal coronary arteries. The exact mechanism of this additive effect is not clear but might be due to the combined action of the two vasoactive drugs with different mode of actio

Coronary vasomotor tone during static and dynamic exercise

Coronary vasomotion is an important determinant of myocardial perfusion in patients with angina pectoris, and it influences not only normal but also stenotic coronary arteries. The ability of a stenotic coronary artery to change its size is dependent on the presence of a normal musculo-elastic wall segment within the stenosis (i.e., eccentric stenosis). Coronary vasoconstriction of normal and stenotic coronary arteries has been reported by Brown and coworkers (Circulation 1984; 70: 18-24) during isometric exercise. The effect of dynamic exericse on coronary vasomotion was evaluated in one group of 13 patients with ischaemia-like symptoms and normal coronary arteries (group 1) and in a second group of 12 patients with coronary artery disease with exercise-induced angina pectoris (group 2). Luminal area of a normal and a stenotic vessel segment was determined by biplane quantitative coronary arteriography at rest, during supine bicycle exercise and 5 min after administration of 1·6 mg sublingual nitroglycerin. Coronary sinus blood flow was measured in group 1 at rest and after 0·5 mg kg−1 intravenous dipyridamole using coronary sinus thermodilution. Coronary flow reserve was calculated from coronary sinus flow after dipyridamole divided by coronary sinus flow at rest. In group 1, coronary vasodilation of the large (i.e., proximal) and the small (i.e., distal) coronary arteries was observed during exercise in seven patients (subgroup A). However, in the remaining six patients (subgroup B) coronary vasoconstriction of the small arteries (−24%, P<0·001) was found during exercise, whereas the large vessels showed coronary vasodilation (+26%, P<0·001). Coronary flow reserve was significantly (P<0·05) larger in subgroup A (mean 2·5) than in subgroup B (mean 1·2) with exercise-induced vasoconstriction of the small epicardial arteries. In group 2 vasodilation of the normal (+23%, P<0·001) and vasoconstriction of the stenotic coronary arteries (−29, P<0·001) was found during supine bicycle exercise. Administration of sublingual nitroglycerin at the end of the exercise test was accompanied by coronary vasodilation of both normal (+40%, P<0·001 vs rest) and stenotic (+12%, NS vs rest) vessel segments. It is concluded that isometric exercise is associated with reflex coronary vasoconstriction of the normal and stenotic vessel segments due to enhanced sympathetic stimulation. Dynamic exercise in patients with ischaemia-like symptoms and normal coronary arteries is accompanied by an abnormal dilatory response of the small coronary arteries in a subgroup of patients with reduced coronary flow reserve. Dynamic exercise in patients with coronary artery disease is, however, associated with coronary vasodilation of the normal and coronary vasoconstriction of the stenotic vessel segments. The nature of this exercise-induced vasoconstriction of stenotic coronary arteries is not clear, but might be related to endothelial dysfunction with an insufficient production of the endothelium-derived relaxing factor during exercis

Artificial reefs: from ecological processes to fishing enhancement tools

info:eu-repo/semantics/publishedVersio

Search for the decay J/ψ→γ+invisibleJ/\psi\to\gamma + \rm {invisible}

We search for $J/\psi$ radiative decays into a weakly interacting neutral particle, namely an invisible particle, using the $J/\psi$ produced through the process $\psi(3686)\to\pi^+\pi^-J/\psi$ in a data sample of $(448.1\pm2.9)\times 10^6$ $\psi(3686)$ decays collected by the BESIII detector at BEPCII. No significant signal is observed. Using a modified frequentist method, upper limits on the branching fractions are set under different assumptions of invisible particle masses up to 1.2 $\mathrm{\ Ge\kern -0.1em V}/c^2$. The upper limit corresponding to an invisible particle with zero mass is 7.0$\times 10^{-7}$ at the 90\% confidence level

Colaboração família-escola em um procedimento de leitura para alunos de séries iniciais

O presente estudo teve por objetivo utilizar o procedimento de “leitura conjunta”, envolvendo a colaboração dos pais. Estes deveriam ouvir a leitura de textos, duas vezes por semana, feita pelo filho, aluno de segunda série do ensino fundamental, que escolhia um tema do seu interesse. Cada sessão durava cinco minutos, havendo um teste de compreensão da leitura, aplicado antes e depois das seis semanas de uso do procedimento. Os pais responderam a um questionário sobre a sua percepção acerca da leitura do filho. Houve melhora no desempenho em leitura e, embora o grupo de controle também tenha melhorado, os dados mostraram a possibilidade da participação dos pais no processo de construção da leitura do filho.</jats:p

Endovascular treatment of thoracic aortic disease: Four years of experience

Background-The aim of this retrospective study is to investigate efficacy and middle-term results of the stent graft treatment for diseases of descending thoracic aorta. Methods and Results-From March 1999 to October 2003, 132 patients (113 male and 19 female, mean age 62±14 years) were enrolled. They were divided into 4 groups: aneurysms (43, group A), post-traumatic lesions (24, group B), and complicated type B dissections (43, group C). Twenty-two further patients, with chronic type B dissection and not suitable for endovascular or surgical or hybrid techniques because of multiple entry tears without difference between the true and false lumen and poor clinical conditions, were obliged to receive medical management only (group D). All patients underwent computed tomography (CT) scan and angiography as preoperative assessment. An optimal deployment with exclusion of the aneurysm and/or closure of the entry tear in dissection was achieved in 96.4% (106/110) of the patients that were discharged in good conditions within 6 days. No spinal cord injuries were observed. The follow-up (average 20.82±10.01 months, range 1 to 55 months), performed with serial chest CT scans, was 100% complete. No stent graft-related complications were detected, although only in 1 case, an asymptomatic rupture of the Excluder connecting bar was found with a perforation of the fabric and an intra-aortic exposition of the bar itself. In 2 patients with chronic dissection an asymptomatic type II endoleak was detected. A total of 4 hospital deaths resulted in an overall operative mortality of 3.9%. Seven patients (6.3%) died during the follow-up 5 of them for other diseases (4.5%). However, a 40.9% mortality was observed within the obliged medical treatment group. Conclusions-Endovascular treatment of thoracic aortic diseases, even in the acute phase, may represent a valid option with a low mortality rate. Moreover, the efficacy is proved in the middle-term whereas the long-term follow-up is still pending