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Biomedical subjects

O Visioli

Publications and source records attributed to O Visioli.

At least 163 records · Page 9Linked to original sources
PubMed1984

Reversible and irreversible ischaemic damage: importance of energy metabolism.

In this study the effects of different degrees and duration of coronary flow reduction on pressure development of the isolated and perfused rabbit hearts has been studied. Three different degrees of ischaemia lasting for 30, 60 and 90 minutes have been investigated, after which the effects of post-ischaemic reperfusion have been followed. The effects of substituting FFA for glucose as myocardial substrate has also been investigated. Reperfusion resulted in a recovery of mechanical function or in a further worsening of mechanical function, depending upon the degree, duration of flow reduction and substrate employed. To establish the causes of reperfusion damage, in a separate series of experiments the effects of reperfusion after 90 minutes of severe ischaemia on lactate, CPK and Mg++ release, tissue and mitochondrial calcium content tissue ATP and CP concentration and mitochondrial function have been determined. The ultrastructural damage of the myocardial cell have also been established. The results obtained suggest that mitochondria play an important role in reperfusion damage.

Adenosine Triphosphate↗
PubMed1983

Iopamidol: a new contrast medium in coronary angiography. Comparison, on electrophysiological changes in man, with a commonly used contrast medium.

In 30 patients undergoing coronary angiography the effects of Iopamidol on sinus node activity, atrioventricular and intraventricular conduction were evaluated using His Bundle recordings, and compared to the effects produced by Diatrizoate. Diatrizoate resulted in an increase in sinus cycle length and prolonged AV nodal conduction, resulting in second degree AV block in two patients. Iopamidol had significantly less effect on sinus cycle (P less than 0.01) and AV nodal conduction (P less than 0.01). Neither contrast media affected intraventricular conduction. No difference was noted in the imaging power of the two contrast media. It is suggested that non-ionic, low osmotic contrast media such as Iopamidol will result in increased patient safety during coronary angiography without loss of imaging power.

Adult↗
PubMed1983

Vitamin E and the heart: possible role as antioxidant.

When cardiac muscle becomes hypoxic the cells become oedematous and the fine ultrastructure is altered. Developed tension declines and resting tension increases. The cellular stores of ATP and CP are depleted and the mitochondria exhibit an altered respiration, characterized by a reduced state III respiration and a lowered respiratory control index. Reoxygenation results in a further increase of the hypoxic damage. Using these changes in function as indices of the severity of the damage caused by hypoxia and reoxygenation, we have investigated whether the administration of alfa-tocopherol provides protection. Adult male New Zealand white rabbits were used. The hearts were isolated, Langendorff perfused and then made hypoxic. Alfa-tocopherol acetate was infused directly into the aorta inflow cannula, 20 minutes before the onset of hypoxia and was continued for the remainder of the perfusion. Hypoxia was established by substituting 95% N2 and 5% CO2 + CO2 in the gas mixture. The alfa-tocopherol-treated rabbits hearts were protected in that during hypoxia and particularly during reoxygenation had a lower rate or rise of resting tensions and of ATP and CP depletion. This treatment also maintained mitochondrial function after hypoxia and reoxygenation and it resulted in the preservation of the fine ultrastructure of the myocardium as electronmicroscopic examination of the hearts revealed a marked reduction in oedema, contracture-band formation and mitochondria alterations.

Aerobiosis↗
PubMed1981

Hemodynamic pattern following K-strophanthin in normal and coronary artery disease patients.

Hemodynamic effects of K-strophanthin (0.005 mg/kg i.v.) were evaluated in 7 normal and in 13 non-failing coronary artery disease patients (CAD). Volumetric parameters were obtained by single plane left ventricular angiography. The indexes of "pump" function, the end-systolic pressure-volume relationship and the ratio of peak pressure to systolic volume were also evaluated. Heart rate was maintained constant by atrial pacing. In normal subjects K-strophanthin exerted small effects without peripheral vasoconstriction. CAD patients showed different response to K-strophanthin in vascular tone: an increase (Group 1) or a decrease (Group 2) in total systemic resistance (TSR). No significant differences were found in basal values between the two CAD groups. In Group 2 the indexes of "pump" function increased after K-strophanthin and the end-systolic pressure-volume points shifted upward and to the left, while in Group 1 no improvement in cardiac function was observed and the end-systolic pressure-volume points shifted upward and to the right. Furthermore, we found a direct significant correlation between the percent changes of TSR and end-systolic volume index, and a negative significant correlation between the percent changes of TSR and stroke volume index. Our results show that K-strophanthin in CAD non-failing patients can have either a positive effect or a lack of improvement in ventricular performance. These effects correlate with changes in total systemic resistance.

Adult↗
PubMed1981

Tardokinesis in coronary artery disease: evidence with instantaneous analysis of left ventricular ejection.

Instantaneous measurements of ejection phase indices throughout the whole systole have been performed in 10 normal subjects (normal group), and in 8 coronary artery disease (CAD) patients (CAD group). All the patients of the CAD group were selected from 230 CAD patients because of their normal values in standard ejection phase indices (i.e. ejection fraction, EF; mean velocity of circumferential fiber shortening, VcfM; mean normalized systolic ejection rate, MNSER). An 'instantaneous' evaluation of the ventricular function, by means of a frame-by-frame analysis throughout the ejection period, allowed us to detect abnormalities of ventricular ejection in the early phase of systole in these CAD patients. In comparison with the control group, the CAD group presented similar peak values of dV/dt, dV/dt/EDV and Vcf, and a significantly longer time to peak values of these indices; EF curve analysis showed similar values at the end of systole in the two groups, but the mean curve of the CAD group was significantly lower in the first third of ejection when compared with that of control group. A segmental wall motion analysis in the early phase of systole showed a diffuse delayed ventricular wall motion (tardokinesis) related to abnormalities demonstrated by frame-by-frame analysis of ejection phase indices. Our results confirm that the CAD patients may have abnormalities of ventricular performance in the early phase of systole even when standard ejection phase indices are still within the normal range. In addition, the chronological appearance of these abnormalities during the whole systole has been clearly assessed; finally, these data confirm the importance of acceleration in blood ejection from the left ventricle as an index of ventricular function.

Adult↗
PubMed1981

[The effects of digoxin administration on normal and pathological sinus node function. An electrophysiological study (author's transl)].

In 12 normal subjects (group I), in 12 subjects with asymptomatic sinus bradycardia (group II) and in 18 patients with symptomatic sick sinus syndrome (group III), sinus node cycle length (SNCL), sinus node recovery time (SNRT), corrected sinus node recovery time (CSNRT), sino-atrial conduction time (SACT), have been evaluated before and after an acute digoxin administration. Mean value of SNCL lengthened significantly in all groups. Mean value of SNRT increased moderately in the first group, remarkably in the third group, whereas it showed a mild but statistically insignificant increase in the second group. Mean value of CSNRT was significantly lengthened only in the third group. Mean value of SACT showed a mild but statistically insignificant lengthening in all groups. In order to investigate the importance of the parasympathetic action induced by digitalis, in 4 normal subjects, in 4 patients with asymptomatic sinus bradycardia, and in 10 patients with symptomatic sick sinus syndrome, SNCL, CSNRT and SACT has been evaluated after an intravenously, administration of atropine, following digoxin. In the paper the intricate mechanisms by which digitalis affects the parameters of sinus nodal function especially in patients with symptomatic sick sinus syndrome, are discussed. In disagreement with the mot papers reported in the literature we think that an acute digoxin administration is able to worsen the electrophysiological parameters of sinus nodal function especially in patients with symptomatic sick sinus syndrome.

Adult↗
PubMed1980

[Arterial blood pressure in a population of Italian clerical workers. Correlation with other coronary risk factors].

Distribution of arterial blood pressure and prevalence of hypertension have been reported in 172 subjects (568 males and 144 females), derived from screening of a bank clerks population. 99 subjects were found to be hypertensive: 46 (46.4 p. 100) were aware of being hypertensive, 24 (24.3 p. 100) resulted to be under treatment and only in 5 subjects blood pressure values were effectively controlled. The relationships between arterial blood pressure and some recognized or suspected coronary risk factors were also determined by multiple regression analysis. Age, heart rate, body mass index, glycemia after loading, turned out the variables most correlated with blood pressure. The multiple regression analysis showed that overall evaluation of coronary risk factors explained up to 21 p. 100 of the systolic blood pressure variation and to 17 p. 100 of diastolic pressure in male subjects, while for women the obtained values were 34 p. 100 and 24 p. 100 respectively. After a critical evaluation of different parameters able to affect arterial blood pressure, the difficult approach to hypertension preventive and therapeutic problems was emphasized.

Adult↗
PubMed1980

[Effect and action mechanism of hypothermia to preserve the ischaemic myocardium (author's transl)].

The ability of hypothermia (34 degrees, 28 degrees) to preserve cardiac metabolism and performance during ischemia, was evaluated in the isolated Langendorff perfused rabbit heart. The hearts, isolated and perfused aerobically for 20', were made ischemic for 90' and their wall temperature maintained either at 37 degrees, 34 degrees and 28 degrees. The hearts were consequently reperfused at 37 degrees for 30'. Some of the hearts were frozen and assayed for ATP and CP. Others were homogenized and their mitochondria harvest, using either an EDTA free or an EDTA-containing extraction medium. The oxidative phosphorylating and ATP generating capacity of these mitochondria were established and their Ca++ content determined. The mechanical performance of the hearts, which were paced, was monitored by means of an intra-ventricular balloon filled with water and connected with a pressure transducer. The hearts that were made ischemic and maintained at 37 degrees were severely depleted in ATP and CP content, their mitochondria accumulated Ca++ and their oxidative phosphorylating activity was impaired. During reperfusion mitochondrial Ca++ was substantially increased, the capacity of the mitochondria to use O2 for state III respiration was further impaired and their ATP generating capacity reduced. Diastolic pressure increased and there was no recovery of the ability of the hearts to develop sistolic pressure. The hearts made ischemic and maintained at 28 degrees were protected. There was a less marked rise in mitochondrial Ca++ concentration after ischemia and during reperfusion; the mitochondria recovered the capacity of utilizing O2 and of generating ATP. That was coincident with and almost complete recovery of mechanical performance. Hypothermia at 34 degrees during ischemia provoked only a partial protection. These results are discussed in accordance with the hypothesis that hypothermia protects heart muscle against the deleterious effects of ischemia not only by reducing the metabolic requirement but also by maintaining intracellular homeostasis with respect to Ca++.

Adenosine Triphosphate↗
PubMed1980

[The atrial vectorcardiogram at rest and during exercise. Comparison, by computerized analysis, of normal subjects and patients with mitral stenosis].

This study on rest and exercise atrial vectorcardiogram (Frank method) was carried out on a group of 27 healthy volunteers (Group A) and on a group of 24 patients with mitral stenosis (Group B). All 51 subjects were women. Our original program was performed using a Hewlett Packard 2100 computer. The pattern recognition of every wave was carried out by analysing a particular function obtained by translating the X, Y, Z leads on the line joining the T-P, P-Q, ST segments. In the group B on rest a significant correlation between atrial vectorcardiogram parameters and pulmonary capillary wedge pressure was not present. Between both group A and B the vectorcardiographic data were greatly superposables. It is difficult, because of the great interindividual variability of results obtained, to have very discriminant vectorcardiographic parameters between group A and group B on rest and during exercise, performed in the supine position with a bicycle ergometer. In the both groups A and B the exercise induces a significant increase of spatial magnitude of maximal P xyz vector (max P xyz) and maximal P amplitude on frontal and sagittal planes, with P loop shifting towards a vertical position. The following significant results were observed only in group B of mitral patients: 1) an increase of P wave duration; 2) an increase of the interval between the two peaks of P wave (measurable only in group B); 3) an increase in the amplitude and backward rotation of max P xyz azimuth and of the maximal vector backward directed on horizontal (H) plane; 4) an increase of P loop linear, tangential and areolar velocities. The P loop anterior and posterior area on H plane and of the spatial P xyz vectors changes during exercise were directionally similar in the normal group and in the patients with mitral stenosis. These results suggest a little diagnostic power of the P wave area changes during exercise. In both groups maximal atrial T vector increases with exertion, but only in group B migrates backward on H plane, suggesting an atrial gradient directed towards the left atrium.

Adult↗
PubMed1980

Non-invasive evaluation of left ventricular function through systolic time intervals following oral administration of SB 7505 in man.

An investigation on the effect of diisobutyric ester of N-methyl-dopamine (SB 7505) on systolic time intervals (STI), heart rate (HR), systolic arterial pressure (SAP), diastolic arterial pressure(DAP), saluretic activity was carried out on 8 male volunteer in-patients who had normal renal, gastrointestinal, cardiac and hepatic functions and were free from other serious illness. SB 7505 was administered orally at three doses of 50, 100 and 150 mg. HR, SAP and DAP either showed no variations or marginal insignificant shifts. STI decreased evidencing a dose-related positive inotropic effect like digitalis, but shorter than digitalis. SB 7505 also showed diuretic action with all three doses investigated. The positive inotropic effect and diuretic activity point to the possible usefulness of SB 7505 in treating some heart and kidney diseases.

Administration, Oral↗
PubMed1980

Myocardial lactic acid balance after left ventriculography.

In order to study the effects of contrast media on myocardial metabolism the percentage of lactic acid extraction during left ventricular angiography has been determined in 16 normal patients (Group I), and in 29 patients with coronary artery disease (Group II). In addition, the lactic acid uptake was evaluated after atrial pacing (in 10 patients of Group I and in 13 patients of Group II) and after aortography (in 6 patients of Group I and in 9 patients of Group II). Normal patients usually did not show a myocardial lactic acid production after left ventriculography while the patients with coronary artery disease showed a net lactic acid production in the coronary sinus, which was similar to that obtained after atrial pacing stimulation and after aortography. These results indicate that ventriculography can be a useful technique to assess the kinetics of lactic acid uptake or release into the coronary sinus in patients with coronary artery disease and, in this respect could be useful for studying myocardial metabolism in aortic valve disease and to assess the toxicity of different contrast media.

Adult↗