1,721,258 research outputs found
Usefulness and limitations of the positive protosystolic peak of coronary arterial blood flow as an index of epicardial arterial compliance
No full textThe aim of the study was to investigate the physiological meaning of the positive peak which appears at the onset of ventricular ejection on traces of blood flow in the left coronary artery. It was proposed that the protosystolic peak could represent systolic charging of epicardial coronary arterial compliance, i.e. the compliance which is not squeezed by myocardial contraction and which resides in superficial coronary arteries. To verify this hypothesis, blood flow was recorded from the left circumflex coronary artery in five anesthetized open-chest dogs and the protosystolic peak was identified by visual analysis or on the basis of zero-crossing of the first derivative. An index of epicardial compliance (delta V/delta P) was derived by dividing the peak area (delta V) by the aortic pulse pressure (delta P). Under basal conditions, the estimate of epicardial compliance, amounting to 0.271 +/- 0.149 x 10(-3) ml/mmHg (2.04 +/- 1.12 x 10(-12) m4s2kg-1; mean +/- SD), fell in the lower part of the range of values found by different authors and increased during hemorrhagic hypotension, due to nonlinearities of compliance in general. Similar values of epicardial compliance were obtained when a lumped resistance-capacitance parallel model was fitted to systolic coronary blood flow. Unexpectedly, however, the protosystolic peak was greatly decreased during coronary reactive hyperemia. We conclude that the protosystolic peak can be used as an index of epicardial compliance, but only at basal coronary vasomotor tone
Condividere la vita. Donazione e trapianto di organi e tessuti. Conoscenze, opinioni, vissuti psicologici
No full textMortalità nel diabete. In: Il diabete mellito in Italia, 2004. Parte Prima: Epidemiologia
No full textReduced Lung Function in Midlife and Cognitive Impairment in the Elderly
No full textno available; Comment on: Impaired Lung Function, Lung Disease, and Risk of Incident Dementia. [Am J Respir Crit Care Med. 2019
The capture-recapture method in the epidemiology of Type 2 diabetes mellitus – A contribution from the Verona Diabetes Study.
No full textEndogenous adenosine enhances vagal negative chronotropic effect during hypoxia in the anaesthetised rabbit
No full textSTUDY OBJECTIVE--Hypoxia potentiates the negative chronotropic effect of efferent vagal stimulation. A similar potentiation is evoked by exogenous adenosine. The aim of this study was to verify whether vagal potentiation during hypoxia is caused by endogenous adenosine. DESIGN--In anaesthetised rabbits the peripheral end of the right vagus was stimulated once every 20 s for 1 s, during normoxia and during systemic hypoxia, before and after adenosine receptor blockade. Hypoxia was induced by lowering oxygen content of the inspired air for 6 min. EXPERIMENTAL MATERIAL--12 rabbits were anaesthetised with chloralose (50 mg.kg-1, intravenously) and halothane (0.3 vol%) and artificially ventilated. Reflex influences on heart rate were minimised by bilateral cervical vagotomy and administration of atenolol (1 mg.kg-1, followed by 0.25 mg.kg-1.h-1). Hypoxia was repeated before and after 8-phenyltheophylline administration (19.5 mumol.kg-1, intravenously) in seven rabbits, or before and after vehicle injection in five rabbits (time control). MEASUREMENTS AND RESULTS--The PaO2 attained at the end of the hypoxic period was 19(SEM 1) mm Hg [2.5(0.1) kPa]. Before adenosine receptor blockade, arterial pressure increased during hypoxia [14(6)mm Hg after 1 min], then decreased [7.3(8.8) mm Hg below control after 4 min]. Heart rate fell by 38.3(12.1) beats.min-1 in the last 3 min of hypoxia. Vagal negative chronotropic effect increased from -30.3(1.8) beats.min-1 during control to -58.7(4.6) beats.min-1 during the last 5 min of hypoxia, ie, a potentiation of 93.2(9)%. Administration of 8-phenyltheophylline reduced the effects of hypoxia on spontaneous heart rate and vagal bradycardia: heart rate decreased by 14.2(7.8) beats.min-1 and vagal negative chronotropic effect increased from -32.2(2.1) to -39.3(3.7) beats.min-1, ie, a potentiation of 21.5(10)%. Blood pressure showed a stronger increase [19.1(4.4) mm Hg after 2 min], but no decrease. These differences were not seen in the five control rabbits, in which hypoxia was repeated without adenosine receptor blockade. CONCLUSIONS--These results show that adenosine does play a role in hypoxia induced bradycardia and vagal potentiation
Mortalità nel diabete tipo 2
No full textIl capitolo fa il punto sulla mortalità nel diabete tipo 2 e sull'impatto di fattori di rischio cardiovascolari
Epidemiology of esophageal and hypopharyngeal squamous cell carcinoma
No full textThe incidence of esophageal squamous cell carcinoma (SCC) exceeds that of esophageal adenocarcinoma (AC) in all developing countries and in most developed countries, including Italy. By contrast, the incidence of AC has recently approached that of SCC in Scotland, the USA, and Israel.
Cancer of the hypopharynx is rather rare: in France it represents 0.40% of all cancers in men and 0.06% of those in women.
The most important risk factors for SCC of the esophagus and hypopharynx are excessive alcohol consumption, tobacco smoking, low socioeconomic status, and nutritional deficiencies
Gastrectomy with extended lymphadenectomy for primary treatment of gastric cancer (letter)
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