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Biomedical subjects

Lorenzo Bonetti

Publications and source records attributed to Lorenzo Bonetti.

8 recordsLinked to original sources
PubMed2006

Dyspnea during exercise in hyperbaric conditions.

INTRODUCTION: Length-tension and force-velocity characteristics of respiratory muscles and hyperinflation are the likely determinants of dyspnea in subjects exercising under hyperbaric conditions. We hypothesize that hyperinflation plays a minor role and that the reduced velocity of shortening of the respiratory muscles modulates dyspnea for any given pleural pressure. METHODS: We studied five normal subjects who performed an incremental exercise test on a cycloergometer in both normobaric (SL) and hyperbaric (4 ATA) conditions. We measured breathing pattern, inspiratory pleural pressure swing (Pessw), Delta Pes (i.e., the difference between the most and the less negative pleural pressures during tidal breathing), and dyspnea intensity (Borg score). End-expiratory lung volume (EELV) changes were evaluated by measuring changes in inspiratory capacity. Mean inspiratory flow (VT/TI) was used as an index of velocity of shortening of respiratory muscles. RESULTS: Compared with SL, at 4 ATA, peak exercise ventilation (VE) (84.5 vs 62.2 L x min(-1)) and VT/TI (2.99 vs 2.16 L x s)(-1) were lower, Pessw (30.9 vs 38.6 cm H2O) and Delta Pes (43.8 vs 62.2 cm H2O) were higher, and Borg score was not different (7.60 vs 8.20 au). EELV decreased progressively during exercise but remained higher than at SL. Borg score was greater for a same VE and lower for a same Delta Pes. VT/TI was lower for a same Pessw. The differences in EELV between SL and 4 ATA did not relate with the concurrent changes in Borg score. CONCLUSION: The results confirm our hypothesis that during exercise in hyperbaric conditions, decreased velocity of shortening of respiratory muscles modulates pressure-induced increases in dyspnea, with hyperinflation playing a minor role.

Adult↗
PubMed2005

Acute myocardial infarction in young patients: nutritional status and biochemical factors.

PURPOSE: The aim of this study was to establish whether nutritional status and biochemical factors, C-reactive protein (CRP), serum amyloid A (SAA) protein, serum iron (Fe) and fibrinogen at admission were different in patients with acute myocardial infarction (AMI) at a young age (<40 years) vs. those with AMI at an older age (>60 years). We also investigated whether during the stay in the hospital, the increase in acute-phase reactants was different in young vs. older subjects, and if dyslipidemic aspects were different between the two groups. METHODS: The study population consisted of 40 patients, all males with a mean age of 36.7+/-1.16 years, admitted to our facility with AMI. The control group included 40 patients, all males, mean age of 66.3+/-4.24 years, with AMI. CRP, SAA, Fe and fibrinogen were determined at admission to the hospital and daily for 7 days in the two groups of patients. RESULTS: In young patients the median value of the highest levels were 6.2 mg/l (range 0.7-27.30) for CRP, 13.22 mg/l (range 0.7-130) for SAA, 420 mg/dl (range 76-840) for fibrinogen and 49.1 gamma/ml (range 14-102) for Fe levels. In the older patients, the median value of the highest levels were 5.9 mg/l (range 0.6-28.30) for CRP, 12.12 mg/l (range 0.9-280) for SAA, 480 mg/dl (range 60-780) for fibrinogen and 47.1 gamma/ml (range 12-94) for Fe levels. CONCLUSIONS: In the present study, acute-phase reactants were quantitatively similar in young and old patients. On the contrary, nutritional status, homocysteine, LDL and triglycerides are significantly higher in young patients than in old patients.

Acute-Phase Proteins↗
PubMed2003

Left atrial size after cardioversion for atrial fibrillation: effect of external direct current shock.

OBJECTIVE: The aim of this study was to evaluate the effect of external direct current (DC) shock on left atrial (LA) dimension and volumes after cardioversion for atrial fibrillation, and the relation between LA size and atrial function. METHODS: We evaluated 180 patients who were randomly cardioverted with DC shock (90 patients) or drugs (90 patients). Echocardiographic evaluations included LA size and volumes. LA passive and active emptying volumes were calculated, and LA function was measured as atrial ejection force. Changes in LA diameters and volumes were correlate with atrial systolic function. RESULTS: The LA was dilated in all patients during arrhythmia and decreased after the restoration of sinus rhythm. The entity of reduction was different in the 2 groups of patients. LA maximal and minimal volumes were increased after DC shock as compared with patients treated with drugs (LA maximal volume 34 +/- 4 vs 31 +/- 5; P <.01; LA minimal volume 18 +/- 2.6 vs 15 +/- 3.6; P <.01). The atrial function was also depressed after DC shock and the delay in the recovery of atrial contractility was related to LA dilation. Patients treated with drugs had a higher atrial ejection force that was associated with a more marked reduction in LA maximal volume after the restoration of in sinus rhythm. A relationship between LA volumes and atrial ejection force was observed in the group of patients with depressed atrial mechanic function (r = -0.78; P <.001). The active emptying fraction was lower, although not significantly, in this group, whereas the conduit volume was increased. CONCLUSION: External DC shock induced a depressed atrial mechanic function in many patients and this was associated with a persistence of LA dilation.

Adult↗
PubMed2003

Association between atrial septal aneurysm and patent foramen ovale in young patients with recent stroke and normal carotid arteries.

BACKGROUND: Atrial septal aneurysm (ASA) has been considered a potential source of cardiogenic embolism for many years. The ASA Multicenter Italian (ASA-MI) Study evaluated the prevalence and characteristics of ASA in patients with stroke and normal carotid arteries compared with control patients without stroke. The purpose of the present study was to evaluate the frequency of ASA and the association with patent foramen ovale (PFO) in the subgroup of younger patients (aged less than 55 years) included in the ASA-MI Study. METHODS: The ASA-MI Study included 606 patients, enrolled between November 1990 and December 1996: 245 patients with a previous cerebral embolic attack and normal carotid study and a control group of 316 patients. They all underwent transthoracic and transesophageal echocardiography. The subgroup of younger patients aged less than 55 years included 90 patients (61 men and 29 women of mean age 49 +/- 5 years) (group AY). This group was evaluated and compared with an age- and sex-matched control population (61 men; of mean age 48 +/- 6 years) (group BY). RESULTS: The prevalence of ASA was 48.8% (95% confidence interval 40-61) in group AY and 22.2% in the group BY (95% confidence interval 18-33) (chi(2) = 5.968; p = 0.01). Morphological features were similar in the 2 groups of patients. ASA involved the entire septum in 52% of patients of group AY, and in 47.2% of group BY. The prevalence of PFO was 58.8% (95% confidence interval 43-62) in group AY and 28.8% in group BY (95% confidence interval 17-35) (chi(2) = 5.811; p = 0.01). A strong association was found between ASA and PFO. Of the 90 younger patients with stroke, 39 of 44 (88.6%) with ASA also had PFO, compared with 14 of 46 (30.4%) without ASA (chi(2) = 7.370; p = 0.007). CONCLUSION: We found that ASA and PFO were independent predictive factors for stroke in younger patients with stroke and normal carotid arteries and that the association between ASA and PFO bore an increased odds risk.

Adult↗
PubMed2003

The association between atrial septal aneurysm and mitral valve prolapse in patients with recent stroke and normal carotid arteries.

BACKGROUND: The association between mitral valve prolapse (MVP) and cryptogenic stroke is controversial. The Atrial Septal Aneurysm Multicenter Italian (ASA-MI) Study is a prospective multicenter study evaluating the prevalence of atrial septal aneurysm (ASA) in patients with a recent stroke and normal carotid arteries. The aim of the present research was to evaluate the frequency of ASA and its association with MVP in the stroke population and in the subgroup of young patients (< 55 years) included in the ASA-MI Study. METHODS: The study group included 245 of the 606 patients referred for transesophageal echocardiography (168 men and 77 women, mean age 65.7 +/- 21 years). All patients were selected on the basis of a recent episode of unexplained cerebral ischemia and were included in the study if they had normal carotid arteries. The control population included 245 patients (mean age 64.7 +/- 23 years) who underwent transesophageal echocardiographic evaluation during the same period for indications other than cerebral ischemia. The subgroup of young patients (< 55 years) included 90 patients (61 men and 29 women, mean age 49 +/- 5 years). RESULTS: The prevalence of MVP was 18% (95% confidence interval 8 to 21%) in the stroke population and 15% (95% confidence interval 7 to 20%) in the control population (chi 2 = 2.1, p = NS). The prevalence of MVP did not differ between young stroke patients (28.8%) and young controls (20%) (chi 2 = 0.835, p = 0.3). MVP was not significantly associated with stroke. We found an association between ASA and MVP: there was a higher incidence of MVP in stroke patients with an ASA than in patients without stroke or an ASA (40.9 vs 25%, p < 0.05). There was also a higher frequency of MVP associated with ASA in the group of young patients than in all patients of the ASA-MI Study (28.8 vs 18%, chi 2 = 20.313, p < 0.001). CONCLUSIONS: We found an association between ASA and MVP in patients with recent stroke and this association bore a higher risk of cerebral events than in patients without these abnormalities.

Adult↗
PubMed2002

Prognostic role of reversible endothelial dysfunction in hypertensive postmenopausal women.

OBJECTIVES: ; The aim of the present study was to assess whether optimized antihypertensive treatment is effective in modifying endothelial function and whether an improvement in flow-mediated vasodilation (FMD) in response to treatment, as an expression of reversible endothelial dysfunction, could predict a more favorable prognosis in a population of postmenopausal women. BACKGROUND: Hypertensive postmenopausal women have been shown to have abnormal endothelium-dependent vascular function. However, FMD may change over time, according to antihypertensive treatment; the prognostic value of these changes has not been investigated. METHODS: A total of 400 consecutive postmenopausal women with mild-to-moderate hypertension and impaired FMD underwent ultrasonography of the brachial artery at baseline and after six months, while optimal control of blood pressure was achieved using antihypertensive therapy. They were then followed up for a mean period of 67 months (range 57 to 78). Endothelial function was measured as FMD of the brachial artery, using high-resolution ultrasound. RESULTS: After six months of treatment, FMD had not changed (< or = 10% relative to baseline) in 150 (37.5%) of 400 women (group 1), whereas it had significantly improved (>10% relative to baseline) in the remaining 250 women (62.5%) (group 2). During follow-up, we noticed 32 events (3.50 per 100 person-years) in group 1 and 15 events (0.51 per 100 person-years) in group 2 (p < 0.0001). CONCLUSIONS: This study demonstrates that a significant improvement in endothelial function may be obtained after six months of antihypertensive therapy and clearly identifies patients who possibly have a more favorable prognosis.

Antihypertensive Agents↗
PubMed2002

Prognostic value of iron, nutritional status indexes and acute phase protein in acute coronary syndromes.

BACKGROUND: The relation between the inflammatory status during unstable angina and nutritional parameters has not been well described. We sought to investigate the relation between the acute inflammatory status, as evaluated on the basis of high C-reactive protein (CRP) and serum amyloid A levels and laboratory indexes of iron and nutritional status in patients with unstable angina, and whether the variations in iron levels have a prognostic significance. METHODS: The study population consisted of 98 patients admitted to our facility with unstable (group 1: 64 consecutive patients, 52 males, 12 females, mean age 66 +/- 10 years) or stable angina (group 2: 34 patients, 30 males, 4 females, mean age 65 +/- 9 years). The hemoglobin levels, the erythrocyte mean cell volume, serum iron levels, the increase in transferrin levels, the decrease in the percent transferrin saturation, ferritin levels, the nutritional status, and the CRP and serum amyloid A levels were measured. RESULTS: On the basis of a CRP value > 1 mg/dl, 47 patients with unstable angina and 4 patients with stable angina were identified as having active inflammatory disease. The presence of inflammation was associated with significantly lower mean values of hemoglobin, erythrocyte mean cell volume, serum iron and transferrin levels, and percent transferrin saturation in comparison with patients without inflammation. A significant inverse correlation coefficient between a CRP level > 1 mg/dl and hemoglobin, transferrin levels and percent transferrin saturation was observed: the strongest correlation was with serum iron levels. The relative risk of total cardiac events was significantly greater in patients with low serum iron levels than in those with high serum iron levels. CONCLUSIONS: Patients with acute inflammation present altered iron status indexes. Increased CRP levels and reduced serum iron levels are associated with a worse outcome in patients with unstable angina.

Aged↗