Until recently, the measurement in man of left ventricular geometry and hemodynamics and the assessment of alteration in myocardial metabolism early after an abrupt occlusion of a major coronary artery were not feasible. Percutaneous transluminal coronary angioplasty (PTCA), however, now provides a unique opportunity to study the time course of these variables during the transient interruption of coronary flow in the balloon occlusion sequence in patients with single-vessel disease and without angiographically demonstrable collateral circulation [1, 2].
Concrete-Filled Double Skin Tubular (CFDST) beams with stainless steel as the outer tube, carbon steel as the inner tube and sandwiched concrete infill between the tubes are presented. Previous studies on CFDST beams have revealed significant enhancements in flexural capacity due to the interaction between concrete and metal tubes. In this study, an innovative form of CFDST beam has been proposed, whereby the inner tube is positioned in the tensile zone of the sections. Hence, the beam sections can resist higher bending moment compared to those sections with the inner tube located at the centroid. A series of tests was performed on CFDST beams with an eccentric inner tube. Nine three-point major-axis bending tests were conducted. The full moment–deflection histories, moment capacities and failure modes of the CFDST beams are presented herein. The experimental results were used to evaluate the bending resistances predicted by the American and European Specifications.
We studied the role of histamine H3-receptors on neurogenic microvascular leakage in guinea pig airways by measuring extravasation of Evans blue dye. In guinea pig airways the major component of the neurogenic leakage is nonadrenergic noncholinergic (NANC) mediated, due to release of tachykinins. Anesthetized guinea pigs were pretreated with propranolol and atropine to block the beta-adrenergic and cholinergic responses and with mepyramine and cimetidine to block histamine H1- and H2-receptors, respectively. Vagal stimulation significantly increased leakage of dye in trachea (Tr), main bronchi (MB), and central (cIPA) and peripheral intrapulmonary airways (pIPA). The selective H3-receptor agonist (R)-alpha-methylhistamine (alpha-MeHA, 0.3-3 mg/kg iv) did not alter basal leakage but inhibited NANC-mediated leakage in a dose-dependent manner with a maximal inhibition of 56.9 (Tr, P less than 0.01), 66.7 (MB, P less than 0.01), 67.5 (cIPA, P less than 0.01), and 58.2% (pIPA, P less than 0.05) at 1 mg/kg. Pretreatment with phentolamine (2.5 mg/kg iv) had no effect on the inhibitory response produced by alpha-MeHA, but the H3-receptor antagonist thioperamide (5 mg/kg ip) blocked its effect. Exogenous substance P (1 microgram/kg iv) caused comparable plasma leakage to NANC-mediated response but was not inhibited by alpha-MeHA. We conclude that H3-agonists inhibit neurogenic leakage by prejunctional inhibition of neuropeptide release from airway sensory nerves.
Chronic obstructive pulmonary disease (COPD) is associated with high morbidity, mortality, and health-care costs. An incomplete response to the anti-inflammatory effects of inhaled corticosteroids is present in COPD. Preclinical work indicates that 'low dose' theophylline improves steroid responsiveness. The Theophylline With Inhaled Corticosteroids (TWICS) trial investigates whether the addition of 'low dose' theophylline to inhaled corticosteroids has clinical and cost-effective benefits in COPD. TWICS is a randomised double-blind placebo-controlled trial conducted in primary and secondary care sites in the UK. The inclusion criteria are the following: an established predominant respiratory diagnosis of COPD (post-bronchodilator forced expiratory volume in first second/forced vital capacity [FEV1/FVC] of less than 0.7), age of at least 40 years, smoking history of at least 10 pack-years, current inhaled corticosteroid use, and history of at least two exacerbations requiring treatment with antibiotics or oral corticosteroids in the previous year. A computerised randomisation system will stratify 1424 participants by region and recruitment setting (primary and secondary) and then randomly assign with equal probability to intervention or control arms. Participants will receive either 'low dose' theophylline (Uniphyllin MR 200 mg tablets) or placebo for 52 weeks. Dosing is based on pharmacokinetic modelling to achieve a steady-state serum theophylline of 1–5 mg/l. A dose of theophylline MR 200 mg once daily (or placebo once daily) will be taken by participants who do not smoke or participants who smoke but have an ideal body weight (IBW) of not more than 60 kg. A dose of theophylline MR 200 mg twice daily (or placebo twice daily) will be taken by participants who smoke and have an IBW of more than 60 kg. Participants will be reviewed at recruitment and after 6 and 12 months. The primary outcome is the total number of participant-reported COPD exacerbations requiring oral corticosteroids or antibiotics during the 52-week treatment period. The demonstration that 'low dose' theophylline increases the efficacy of inhaled corticosteroids in COPD by reducing the incidence of exacerbations is relevant not only to patients and clinicians but also to health-care providers, both in the UK and globally. Current Controlled Trials ISRCTN27066620 was registered on Sept. 19, 2013, and the first subject was randomly assigned on Feb. 6, 2014.
Recurrent angina after percutaneous or surgical coronary procedures may occur as a consequence of several potential causes, such as bypass graft failure, restenosis, or atherosclerotic disease progression. Repeat invasive procedures are frequently performed for patients with recurrent symptoms. Nevertheless, non-invasive pharmacological treatment to decrease disease progression or reduce anginal symptoms are an integral part of the management of the patients. New metabolic modulators such as trimetazidine may constitute important therapeutic agents in the symptomatic control of patients with recurrent angina after invasive revascularization.
