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Biomedical subjects

G Gigli

Publications and source records attributed to G Gigli.

At least 37 records · Page 2Linked to original sources
PubMed1996

[Balanced beta--alpha-blocker treatment with carvedilol in mild-moderate arterial hypertension].

The search for the ideal antihypertensive drug is ongoing. Carvedilol is a new beta-adrenoceptor antagonist which also causes peripheral vasodilation primarily via alpha 1-adrenergic blockade. Twenty patients with mild to moderate essential hypertension and previous intolerance and side effects to other antihypertensive drugs were studied. After initial baseline assessment, patients received 25 mg carvedilol orally q.d. The treatment lasted 60 days. In our study carvedilol was well tolerated and no important side effect was recorded. Blood pressure decreased significantly to normal values, without orthostatic blood pressure decreases. Heart rate decreased significantly too, but no significant bradycardia was induced. No negative effects on serum lipids and no clinical evidence of increase in peripheral resistance were observed. Ventricular arrhythmia on Holter monitoring were significantly reduced after treatment with carvedilol.

Adrenergic alpha-Antagonists↗
PubMed1995

The multicentre trial philosophy in stress echocardiography: lessons learned from the EPIC study. EPIC-EDIC Study Project. Echo Persantine International Cooperative Study. Echo-Dobutamine International Cooperative Study.

The scientific assessment of diagnostic tests should not be based upon a small series of results published by the best academic institutions, but ought to require large scale, multicentre validation founded on grass roots institutions with real doctors, real patients and real problems. To this purpose, an international network of stress echo laboratories has been organized, and within a few years has collected data from thousands of studies using pharmacological stress echocardiography, performed with either dipyridamole (EPIC: Echo Persantine International Cooperative Study) or dobutamine (EDIC: Echo Dobutamine International Cooperative Study) stresses. In a widely deregulated field, all network laboratories have agreed: to pass a quality control examination on stress echo reading before entering the study; to adopt an identical drug infusion protocol; to code similarly the LV segments; and to adopt a common scoring system for wall motion analysis. A minimum amount of historical, clinical, and-when available-stress electrocardiographic, angiographic and follow-up data have been collected on each patient, and disseminated in the various centres, facilitating the creation of an international stress echo language that will help, not only the production of high quality scientific data, but also the build up of a common stress echo lab, with a standardized way of making the studies, unifying the methods and terminology, and archiving data. To date, we have 50 echo laboratories from 15 nations across four continents (Europe, America, Asia and Africa) actively involved in this project. These data will ultimately fill the gap between the academic theory of journals and the pragmatic experience of daily life in a busy echocardiographic laboratory.

Echocardiography↗
PubMed1994

Regression of hypertensive myocardial hypertrophy does not affect ultrasonic myocardial reflectivity: a tissue characterization study.

OBJECTIVE: Ultrasonic backscatter from the myocardial walls is directly related to the morphometrically or biochemically evaluated collagen content in man, and shows a normal pattern of quantitatively assessed ultrasonic backscatter in hypertensive patients, even in the presence of left ventricular hypertrophy. Whether the pharmacologically induced regression of left ventricular hypertrophy in hypertensive patients is accompanied by a disproportionate increase in relative connective tissue content is not yet known. The objective of the present study was to assess the effects of regression of left ventricular hypertrophy on the quantitatively evaluated myocardial reflectivity in essential hypertensives. DESIGN: We evaluated 19 mild-to-moderate essential hypertensives with echocardiographically assessed left ventricular hypertrophy, before and after 8 months' effective antihypertensive therapy with 20-40 mg enalapril once a day, associated with diuretics or calcium antagonists, or both, in six patients to achieve optimal blood pressure control. Using a modified echo machine developed in the Institute of Clinical Physiology, Pisa, an on-line radio-frequency analysis was performed to obtain quantitative operator-independent measurements of the integrated backscatter signal of the ventricular septum and the posterior wall. The integrated values of the radio-frequency signal from the myocardial walls were normalized for those from the pericardial interface and were expressed as percentages (integrated backscatter index). RESULTS: In comparison with baseline, the treated hypertensives showed significant decreases in mean blood pressure, left ventricular mass index, and septal and posterior wall thickness. However, integrated backscatter index values were similar at baseline and after therapy for both the septum and the posterior wall. CONCLUSION: Antihypertensive therapy with enalapril does not increase myocardial reflectivity, although it does induce regression of left ventricular hypertrophy. This suggests that, in accord with experimental data, regression of hypertrophy is achieved by enalapril through a proportionate regression of the myocyte and connective tissue components of the myocardium.

Cardiomegaly↗
PubMed1993

Increased echodensity of transiently asynergic myocardium in humans: a novel echocardiographic sign of myocardial ischemia.

OBJECTIVES: This study was conducted to establish whether changes in myocardial texture can be observed in humans by transthoracic echocardiography during ischemic episodes of different severity and duration induced by various pathogenetic mechanisms. BACKGROUND: Increased echo-reflectivity of ischemic myocardium has been detected in experimental animals by epicardial echocardiography and by backscatter evaluation. METHODS: Transthoracic two-dimensional echocardiographic monitoring with a commercially available electronic sector scanner (2.25- or 3.5-MHz transducer) was performed during 35 episodes of transient myocardial ischemia induced by ergonovine in patients with vasospastic angina (n = 9), by dipyridamole in patients with angiographically assessed coronary artery disease (n = 11) and by balloon occlusion during coronary angioplasty (n = 15). Quantitative texture analysis of gray levels was performed off-line on digitized images during rest conditions, ischemia and the recovery phase in regions showing normal contraction at rest, obvious dyssynergy during ischemia and normal contraction in the recovery phase. In each condition, a control region with normal contraction throughout the study was also evaluated. RESULTS: Chest pain occurred in 23 of the 35 episodes; electrocardiographic (ECG) changes were present in 26 episodes, and consisted of ST segment elevation in 13, ST segment depression in 10 and pseudonormalization of a basally negative T wave in 3. The duration of ischemic episodes was 67 +/- 53 s by symptomatic criteria and 91 +/- 52 s by ECG criteria. The risk region showed an increased end-diastolic mean gray level amplitude in a.u. (arbitrary units) during ischemia (57 +/- 19) compared with rest (38 +/- 15) and recovery (38 +/- 18, p < 0.01). No significant changes were detected in the control region (rest 36 +/- 16 vs. ischemia 34 +/- 18 vs. recovery 31 +/- 13, p = NS). The percent increase in mean gray level was similar in the various types of stress employed (ergonovine, dipyridamole or angioplasty) and was not significantly correlated with either the duration of ST segment shift (r = 0.05, p = NS) or the severity of dyssynergy evaluated semiquantitatively by means of the wall motion score (r = 0.28, p = NS). In the 15 balloon occlusions performed in six patients during coronary angioplasty, the increased echoreflectivity of the risk zone was already evident during echocardiographic sampling performed after 10 +/- 4 s of occlusion (rest 35 +/- 9 vs. 53 +/- 10 a.u., p < 0.01) when no dyssynergy could be detected by quantitative wall motion analysis (percent area change by fixed center of mass reference system 31 +/- 10% at rest vs. 32 +/- 11% after 10 s of occlusion, p = NS). CONCLUSIONS: Transient short-lasting myocardial ischemia is associated with an abrupt increase in myocardial echodensity detectable by videodensitometric analysis applied to standard transthoracic echocardiographic images and is largely independent of the underlying pathogenetic mechanism (reduced blood supply or flow maldistribution with coronary stenosis). During controlled coronary occlusion, increased echodensity precedes the onset of regional dyssynergy.

Analysis of Variance↗
PubMed1993

Normal ultrasonic myocardial reflectivity in hypertensive patients. A tissue characterization study.

Ultrasonic backscatter of myocardial walls is directly related to the morphometrically evaluated collagen content in humans. The integrated backscatter is also increased in hypertrophic cardiomyopathy, whereas it gives normal values in the physiological hypertrophy of elite athletes. We assessed the quantitatively evaluated myocardial reflectivity in 46 mild to moderate, clinically uncomplicated essential hypertensive patients, with echocardiographically assessed normal regional and global left ventricular function, and 22 age- and sex-matched normotensive control subjects. With an echo prototype implemented in our institute, we performed an on-line radiofrequency analysis to obtain quantitative operator-independent measurements of the integrated backscatter signal of the ventricular septum and posterior wall. The integrated values of the radiofrequency signal of myocardial walls were normalized for those of the pericardial interface and expressed as a percent (integrated backscatter index). Hypertensive patients and control subjects differed in mean blood pressure (119 +/- 11 versus 95 +/- 5 mm Hg, p < 0.001) and left ventricular mass index (134 +/- 31 versus 105 +/- 21 g/m2, p < 0.001). However, integrated backscatter index overlapped for both the septum (28 +/- 17% versus 25 +/- 6%, p = NS) and the posterior wall (13 +/- 7% versus 13 +/- 4%, p = NS). In the hypertensive group, there was no detectable correlation between septal integrated backscatter index and either septal thickness (r = -0.26, p = NS) or mean arterial pressure (r = -0.14, p = NS). Hypertensive patients showed a normal pattern of quantitatively assessed ultrasonic backscatter, even in the presence of left ventricular hypertrophy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Identification of viable myocardium by dipyridamole-induced improvement in regional left ventricular function assessed by echocardiography in myocardial infarction and comparison with thallium scintigraphy at rest.

In patients with coronary artery disease and left ventricular impairment, the distinction between ventricular dysfunction due to myocardial fibrosis and postischemic, viable, although dys-synergic, myocardium has important clinical implications. Experimental studies have shown that dipyridamole can increase myocardial function in stunned segments, outlining a potential role of dipyridamole-induced functional recovery as an ultrasonic marker of myocardial viability. The aim of this study was to assess whether the increase of regional left ventricular function early during dipyridamole infusion in basally asynergic segments could identify viable myocardium recognized by rest injected, delayed (greater than 14 hours from tracer injection) thallium and (in a subset of patients) late functional recovery evaluated by a follow-up echocardiogram at rest. Twenty-two patients with angiographically documented coronary artery disease and regional dysfunction in resting conditions (average left ventricular ejection fraction 43 +/- 8%) were studied by echocardiography. All patients underwent a dipyridamole-echocardiographic test (up to 0.84 mg/kg over 10 minutes) and a delayed planar thallium study. A 13-segment model was used for both techniques. A score index ranging from 1 (normokinesia) to 4 (dyskinesia) was used for echocardiography. Thallium-201 activity was expressed in each segment as the percentage of maximal activity in the corresponding view. After dipyridamole, the wall motion score was assigned to each segment in resting conditions and at peak hyperkinesia before possible mechanical signs of ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Angiography↗
PubMed1992

[Spectrum analysis of the r-r interval using a PC].

Spectral analysis of r-r variability has been recently proposed as a clinical tool to assess the autonomic nervous system function. In this article we present the results obtained using an equipment and an analysis software (based on Maximum Entropy Method) developed in our laboratory. Analyzing the tachograms derived from prolonged ECG registrations of 12 young healthy subjects, 24 to 36 years old (mean 31 +/- 4), we observed the two classic components of the signal: a low frequency component (0.7 +/- 0.2 Hz) and a high frequency component (0.21 +/- 16.6 Hz). As expected, standing, a simple manoeuvre augmenting sympathetic activity, caused a stronger predominance of the low frequency component. We conclude that our method is reliable to evaluate, by means of spectral analysis, rhythmical oscillations of r-r variability.

Adult↗
PubMed1991

Dipyridamole-echocardiography in coronary artery disease.

Regional wall motion impairment incurred by means of dipyridamole-induced ischemia, is regarded with higher sensitivity and specificity than the conventional findings in the ECG. Based on the latter considerations, a new test, the dipyridamole echocardiogram has been introduced in which the development of regional wall motion impairment is designated as the positive diagnostic criterion. Dipyridamole is a vasodilator of coronary arterioles. During the course of the examination, three consecutively occurring mechanisms are considered responsible for the appearance of dipyridamole-induced ischemia in the presence of coronary stenosis. The ischemia is initially attributed to a steal-effect, then to reflex-induced rise in rate-pressure product and, lastly, to a vasospastic component. In 680 patients with thoracic pain, on use of 0.84 mg/kg over ten minutes, there was a sensitivity of 74% in detection of angiographically-documented coronary artery disease, defined as greater than 70% stenosis in at least one major coronary artery, and a specificity of 95%. The onset of regional wall motion impairment after dipyridamole infusion was correlated with the severity of the disease, the localization of the wall motion impairment enabled delineation of the localization of the stenosis in the coronary vascular system. By means of the dipyridamole echocardiogram, the effectiveness of therapeutic measures such as PTCA, ACVB, medical antianginal treatment and thrombolysis can be assessed. Lastly, the dipyridamole echocardiogram provides important information with regard to prognosis.

Coronary Disease↗
PubMed1991

[Evaluation of the characteristics and performance of an automatic sphygmomanometer (Omega 1400)].

24 hour pressure monitoring is a newly developing technique potentially yielding important informations in hypertensive patients. Numerous automated devices are available whose performance characteristics are poorly documented. To evaluate an automated sphygmomanometer commonly used in our Division (Omega 1400, Invivo Research Laboratories), we performed a series of measurements, simultaneously recording blood pressure in the opposite arm with a common sphygmomanometer. Each measure was then repeated reversing the position of the two devices (manual and automated), thus abolishing possible differences between the two arms. We observed a mean underestimation of 1.90 mmHg of systolic pressure and of 4.82 mmHg of diastolic blood pressure by the automated device. We conclude that the device by us evaluated is not advisable in the basal blood pressure evaluation, but useful in monitoring inpatients.

Automation↗
PubMed1991

[Blood pressure monitoring during hospital convalescence].

Blood pressure ambulatory monitoring has provided numerous and interesting informations on the clinical as well as investigational setting of arterial hypertension. The vast majority of data have been obtained registering blood pressure during the normal daily activities of the patients and surprisingly few studies have been undertaken to evaluate blood pressure behaviour in inpatients. We observed the 24 hours pattern of blood pressure in hypertensive and normotensive inpatients, using an automated sphygmomanometer (Omega 1400), whose performance was previously evaluated by us. The results demonstrate that blood pressure monitoring in inpatients could be a useful tool in managing hypertensive patients.

Adult↗
PubMed1991

[Evaluation of a new immunoturbidimetry technique for measuring microalbuminuria].

Subclinical elevation of urinary albumin excretion is a good predictor of later clinical proteinuria. A simple, sensitive and rapid immunoturbidimetric method was developed to quantify urinary albumin excretion (URIN-PAK ImmunoMICRO LAB, Miles Italia Spa). In the presence of polyethylene glycol 6000, immunocomplex between human albumin and its specific antibody are rapidly formed (5-50 min, at room temperature). Absorbance reading are mode U 340 nm (Automatic Analyzer RA 1000, Technicon). The test is specific for albumin failing to cross react with other plasma proteins present in urine, as well as with glibenclamide, chlorpropamide, phenformin, hemoglobin, glucose, urea and thymol. The present method correlates with SCLAVO H-ALBUMIN RIA Kit (r = 0.9917). The test is suitable for clinical use.

Albuminuria↗
PubMed1985

[Cardioinhibitory reflex provoked by stimulation of carotid sinus in normal subjects and those with cardiovascular disease].

The normal range and the reproducibility of the cardioinhibitory carotid sinus reflex were studied in 288 apparently healthy subjects of different ages (aged from 17 to 84 yrs., 156 males, 132 females). In each subject we chose the longest RR interval as an activation index of the reflex obtained by carotid sinus massage; its mean value increased slightly with advancing age. In the were 1, 5, 2, 5, 3, 3 sec. respectively, with a 99% confidence limit. No sex difference was found. We studied also a group of 105 patients (aged from 39 to 82 yrs., 67 males, 38 females) with various types of cardiovascular disorders, without a previous history of spontaneous syncope. Abnormal maximum RR values were found in 18 of them (17%). This percentage was significantly higher than in normals (2%). In 11 patients (10%) the carotid sinus stimulation evoked a syncopal attack. It seems therefore that a statistically abnormal carotid sinus hypersensitivity can occur in a substantial number of cardiovascular patients without necessarily leading to spontaneous syncopal attacks. Finally the reproducibility of the cardioinhibitory reflex was tested in 42 patients with maximum RR interval values ranging from normal to extremely abnormal. In each subject a significant correlation (r = 0.79) was found between the maximum RR interval values tested in two occasions at intervals ranging from 1 hour to 3 months; besides a concordance in normal or abnormal result was present in 93% of the cases.

Adolescent↗
PubMed1979

Blood colony-forming cells (CFU-C) and leucocyte colony-stimulating activity (CSA) in patients with neutrophilic leucocytosis.

The incidence of circulating colony-forming cells (CFU-C) and the ability of peripheral leucocytes to stimulate the colony formation (CSA) have been studied through a double layer agar culture system in 26 patients with neutrophilic leucocytosis and compared to the values obtained in 26 normal subjects. Both mean CFU-C incidence and mean leucocyte CSA of the whole group of patients were found significantly higher than normal, but considerable variation was observed among singular patients. The different patterns of blood CFU-C and leucocyte CSA are discussed. The combined evaluation of blood CFU-C and leucocyte CSA is found a useful tool to investigate the pathogenetic mechanisms of neutrophilic leucocytosis.

Adult↗
PubMed1979

Normal range of blood colony-forming cells (CFU-C) in humans: influence of experimental conditions, age, sex, and diurnal variations.

Blood colony-forming cells (CFU-C) and colony-stimulating activity obtained from feeder layers of peripheral blood leucocytes (leucocyte CSA) have been studies in 69 normal subjects by means of semisolid agar culture system. Groups of normal volunteers were selected according to sex and age (20 to 45 and older than 60 years) and the results compared. The mean number of circulating CFU-C was significantly lower in young women (20-45 years old) than in males over 60 years of age, but no differences were found among the other age and sex groups. Leucocyte CSA did not significantly differ among these groups. In 5 young males the blood CFU-C did not show significant variations at 8 AM and at 4 PM of the same day. When the study was repeated in 18 subjects at longer time intervals, the number of colonies showed a maximum fivefold variation. The amount of plasma and polymorphonuclear granulocytes present in our culture system did not inhibit the colony growth. In most cases, double layer cultures grow a higher number of colonies than single layer, but feeder layers of some normal subject seem to inhibit the colony growth.

Adult↗