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Biomedical subjects

E Picano

Publications and source records attributed to E Picano.

At least 199 records · Page 11Linked to original sources
PubMed1986

Transient myocardial dysfunction during pharmacologic vasodilation as an index of reduced coronary reserve: a coronary hemodynamic and echocardiographic study.

Regional coronary flow reserve and regional myocardial contractility were evaluated in 29 patients after maximal pharmacologic coronary vasodilation (intravenous dipyridamole, 0.56 mg/kg body weight, administered over 4 minutes). Nineteen patients had a severe (80 to 99%) proximal and isolated stenosis of the left anterior descending coronary artery and 10 patients had normal coronary arteries; all had normal ventricular function under rest conditions. Myocardial contractility was assessed by means of continuous two-dimensional echocardiographic monitoring; coronary reserve was evaluated by coronary sinus thermodilution. After dipyridamole infusion, 9 of the 19 patients with left anterior descending artery stenosis had transient myocardial asynergy involving the septum or apex, or both (Group IA), whereas 10 patients showed no asynergy (Group IB). No impairment of contractility was observed in the 10 patients with normal coronary arteries (Group II). Coronary blood flow was measured under basal conditions and up to 10 minutes after the end of dipyridamole infusion. In patients in Group II, dipyridamole induced an increase in great cardiac vein flow of 167 +/- 68% (mean +/- SD). The 10 patients in Group IB showed a response comparable with that of the control group (Group II) (136 +/- 45% increase in great cardiac vein flow; NS versus Group II), whereas the 9 patients in Group IA had an increase of 46 +/- 30% (p less than 0.01 versus both Group IB and Group II). No significant difference was found in the angiographic severity of the stenosis expressed in terms of minimal cross-sectional area (Group IA = 0.30 +/- 0.13 mm2, Group IB = 0.34 +/- 0.18 mm2; p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

High dose dipyridamole echocardiography test in effort angina pectoris.

The dipyridamole echocardiography test (intravenous dipyridamole with two-dimensional echocardiographic monitoring) was performed in 93 patients with effort chest pain and in 10 control subjects. The test was considered positive when regional asynergy appeared after dipyridamole administration. When negative at the low dose (0.56 mg/kg body weight in 4 minutes), the test was repeated on a different day with a higher dose (0.84 mg/kg in 10 minutes). All 93 patients underwent coronary arteriography; 72 of them had significant (greater than 70% luminal reduction) coronary artery disease. Thirty-eight of the 93 patients had a positive low dose dipyridamole echocardiography test; 15 other patients with a negative low dose test had a positive high dose test. All 53 patients with a positive test had significant coronary artery disease; 12 of them had a negative exercise stress test. In relation to the presence of coronary artery disease, the dipyridamole echocardiography test had an overall specificity higher than that of the exercise stress test (100 versus 71%) and a similar overall sensitivity (74 versus 69%). The dipyridamole echocardiography test is feasible in all patients with a good baseline echocardiogram. It detects the site of apparent ischemia more precisely than does an exercise stress test, and can unmask electrocardiographically silent ischemia. If performed in patients with a negative low dose dipyridamole echocardiography test, the high dose test adds sensitivity (probably by achieving maximal dilation in patients in whom the low dose is only partially effective), without any loss in specificity and with no apparent increase in risk.

Adult↗
PubMed1986

Early post-infarction angina: usefulness of dipyridamole-echocardiography test.

Thirty-nine patients with early post-infarction angina (all with significant, angiographically assessed coronary artery disease and a baseline asynergy on 2-D echo), performed a dipyridamole-echocardiography test (DET: 2-D echo monitoring with dipyridamole infusion, 0.14 mg kg-1 min-1 for 4 min). Twenty-nine patients had a positive DET (sensitivity = 74%). Two mechanical patterns of DET-positivity could be identified: a worsening of the asynergy in that same region showing a baseline asynergy (11 patients); a 'de novo' asynergy in a region remote from the one showing a baseline asynergy (18 patients); The prevalence of single-vessel disease was significantly higher in patients with type 1 positivity pattern (6 single-, three double- and two triple-vessel disease), while patients with type 2 positivity always showed a multivessel coronary involvement (8 double-, 10 triple-vessel disease). In 4 of the 10 patients with 3-vessel disease and type 2 asynergy, such asynergy developed in a territory different from the one supplied by the more stenotic non-infarct-related vessel. In conclusion, DET represents a safe and feasible tool effectively to localize ischaemia, relative to the infarcted region, and to evaluate the haemodynamic significance of coronary lesions in patients with post-infarction angina.

Adult↗
PubMed1986

The use of frequency histograms of ultrasonic backscatter amplitudes for detection of atherosclerosis in vitro.

This study was designed to determine whether a quantitative analysis of integrated backscatter amplitude distribution is potentially useful in characterizing the atherosclerotic lesion. One hundred measurements (10 X 10 array) were made in fresh aortic regions (2 cm X 2 cm) of nine normal and 19 atherosclerotic arterial walls. A 10 MHz transducer was used. The integrated backscatter distinguished normal from atherosclerotic specimens (-56.7 +/- 4.3 vs -42.5 +/- 8.9 dB, p less than .01). The shape of the integrated backscatter amplitude distribution was analyzed by calculation of skewness and kurtosis of each arterial region. Both skewness values (0.134 +/- 0.325 vs -0.193 +/- 0.491 in normal and atherosclerotic segments, respectively, p = NS) and kurtosis values (0.055 +/- 0.765 vs -0.610 +/- 0.379, p less than .01) discriminated between the two groups. When only the six atherosclerotic specimens with mostly fatty and fibrofatty sites were considered, skewness and kurtosis still distinguished normal from atherosclerotic regions (0.134 +/- 0.325 vs -0.404 +/- 0.232, p less than .05 and 0.055 +/- 0.765 vs -0.558 +/- 0.337, p less than .05, respectively), while integrated backscatter values did not (-56.7 +/- 4.5 vs -52.3 +/- 6.1 dB, p = NS). In conclusion, atherosclerosis may be detected in vitro by the quantitative analysis of integrated backscatter distribution. This variable could also be of help in the identification of less obvious forms of atherosclerotic disease that are not distinguishable on the basis of integrated backscatter amplitude.

Aorta↗
PubMed1986

Echocardiography in the study of myocardial ischemia in man: the clinical model of Prinzmetal's angina.

Standard echocardiography was employed to study the clinical model of myocardial ischemia with ST-segment elevation, well known as Prinzmetal's angina. Ultrasonic monitoring was performed during the appearance of ST-segment elevation, from onset of pain, during an ergonovine maleate test, hemodynamic monitoring, radioisotopic studies and, occasionally, during routine examinations, when spontaneous episodes occurred. Reliability of findings was supported by two important conditions: each patient acted as his own control, since recording was carried out from basal state to basal state, throughout ischemia, or from ischemia to basal state; behaviour of ischemic walls was compared with that of non-ischemic ones. Echocardiographic findings in acute myocardial ischemia were similar both in spontaneous and in induced episodes and were mainly characterized by: decrease in contractility indices of the ischemic segment, such as wall motion and percent systolic thickening; increase in left ventricular end-systolic and end-diastolic diameter, with a decrease in percent fractional shortening; distorted shape of ventricular cavity, transiently deformed as in a "functional" aneurysm; a sharp demarcation between ischemic and non-ischemic adjacent segment, "step sign", was present only in severe cases. Taking ST-segment elevation as a reference the time sequence of events was studied, correlating mechanical, electric and clinical markers of ischemia. At least three different echocardiographic phases were identified in the evolution of ischemic attacks: Pre-electrocardiographic phase, when mechanical impairment is detected by ultrasounds in the absence of both ST-segment changes and pain; Electrocardiographic phase, when echocardiographic signs of ischemia co-exist with obvious electrocardiographic signs.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris, Variant↗
PubMed1986

Echocardiographic documentation of myocardial ischemia in presence of angina pectoris without ST-T changes.

A frequent clinical problem is to document the elusive entity of electrocardiographically silent myocardial ischemia. Since echocardiography offers a practical tool to detect reversible mechanical changes due to ischemia, 32 patients with angina on effort, and coronary artery disease, and 15 patients with angina at rest were studied. In all 47 patients electrocardiographic changes during effort or rest pain were inconclusive. Combined 12 lead electrocardiographic and 2-Dimensional echocardiographic monitoring were performed: during ergonovine testing in the 15 patients with angina at rest; during dipyridamole testing in the 32 patients with effort angina and a non diagnostic stress test. Interpretable echocardiograms were obtained in all the patients studied. Positivity of both the Ergonovine-Echocardiographic test and the Dipyridamole-Echocardiographic test was based upon the detection of regional transient asynergy. Of the 15 patients who had chest pain at rest in the absence of diagnostic electrocardiographic changes, Ergonovine-Echocardiographic test was positive in 6 (40%). Of the 32 patients who had chest pain in absence of diagnostic electrocardiographic changes during exercise stress testing, the Dipyridamole-Echocardiographic test was positive in 18 (56%). Echocardiographic monitoring in combination with provocative testing (ergonovine and dipyridamole) may be a practical, non invasive, inexpensive tool which is feasible in all patients with good basal echocardiograms and is able to unmask electrocardiographically silent myocardial ischemia by providing objective mechanical evidence of the ischemic event.

Adult↗
PubMed1985

Dipyridamole-echocardiography test in effort angina pectoris.

This study assesses the clinical feasibility and usefulness of dipyridamole infusion for the detection of coronary artery disease (CAD) by using 2-dimensional echocardiography (2-D echo) and 12-lead electrocardiographic monitoring. Dipyridamole infusion (0.14 mg/kg/min for 4 minutes) was performed in 66 consecutive patients with effort chest pain and in 9 control subjects. Among the 28 patients with positive dipyridamole-echocardiography test responses, 18 had diagnostic electrocardiographic changes (ST-segment depression on anterolateral leads), but these changes were unrelated to the site of asynergy. The dipyridamole-echocardiography test had an overall sensitivity of 56% and specificity of 100% for the presence of CAD. Exercise stress testing (EST) had an overall sensitivity of 62% and a specificity of 80%. Thus, the dipyridamole-echocardiography test, which is feasible in essentially all patients with good basal echocardiograms, has a lower overall sensitivity in detecting CAD than EST but a higher specificity, detects the site of apparent ischemia as identified by regional asynergy more precisely than EST, and can unmask electrocardiographically silent effort ischemia.

Adult↗
PubMed1985

Echocardiographic versus hemodynamic monitoring during attacks of variant angina pectoris.

Six attacks of variant angina (2 spontaneous, 4 induced by ergonovine) were studied in 6 patients by combined echocardiographic and hemodynamic monitoring. A decrease of percent systolic thickening of the ischemic wall, which occurred as early as the decrease in peak dP/dt of contraction, was detected before the onset of ST-segment elevation ("pre-electrocardiographic phase"). At this stage, no significant change in left ventricular (LV) end-diastolic pressure or end-diastolic diameter was observed. Subsequently, in the presence of clear-cut ST-segment elevation ("electrocardiographic phase"), percent systolic thickening (an index of regional function) reached its nadir, while dP/dt of contraction (an index of global function) was almost back to preischemic values. In this phase, a significant increase in LV end-diastolic diameter and end-diastolic pressure could be also detected. In the recovery phase, when the ST segment had returned to the isoelectric line ("post-electrocardiographic phase"), percent systolic thickening and dP/dt of contraction showed supernormal values, while LV end-diastolic pressure and end-diastolic diameter decreased below basal values. Thus, echocardiographic signs of impairment in LV mechanics are as early and sensitive as hemodynamic indexes during attacks of variant angina. Furthermore, information on morphologic characteristics and regional LV function, not available with hemodynamic monitoring, can be obtained by echocardiography.

Adult↗
PubMed1985

Transient myocardial ischemia with minimal electrocardiographic changes: an echocardiographic study in patients with Prinzmetal's angina.

Kn patients with Prinzmetal's angina, episodes of transient T wave abnormalities (T abn) are often documented in addition to the typical episodes of ST segment elevation (ST). As the interpretation of these minor ECG changes is still uncertain, we investigated if transient T abn are associated with reversible ventricular asynergies, similar to episodes with ST. For this purpose an ECG lead and a two-dimensional echocardiographic projection, which showed clear-cut changes during previous episodes of ST, were simultaneously monitored in five patients with Prinzmetal's angina for a total of 13 hours and 20 minutes. In all patients, the 30 episodes of ST recorded were all accompanied by reversible ventricular asynergies. Furthermore, in four of these patients, 14 episodes of T abn (peaking, flattening, or the appearance of a diphasic T wave) were recorded. All T abn were associated with reversible asynergies, as detected by three independent observers. The mechanical impairment occurred in the same ventricular wall both during ST and during T abn. During T abn the degree of mechanical impairment appeared less severe (hypokinesia in 12 and akinesia in two episodes) than during ST (hypokinesia in one, akinesia in 25, and dyskinesia in four episodes) (p less than 0.001). The duration of asynergies was less during T abn (107 +/- 76 seconds) than during ST (169 +/- 83 seconds) (p less than 0.05). Chest pain was reported in 5 of 14 episodes of T abn (36%) and in 20 of 30 (66%) episodes of ST (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Ultrasonic energy-based technique for characterizing atherosclerosis.

For the characterization of atherosclerotic disease in human aortic specimens two indices of ultrasonic signal loss have been developed. They are based on an energy evaluation of broadband pulsed ultrasound and have been introduced in order to minimize phase cancellation artifacts caused by phase sensitive transducers. Both indices are derived from the transfer function H(f) of the specimen, they are: the slope of ln H(f) for the evaluation of signal loss due to absorption and scattering inside the specimen thickness, and s ln H(f) df, which reflects changes in both the internal and the intimal surface properties of the aorta. The results indicate that methods based on the evaluation of signal loss inside the aortic thickness are insensitive to surface irregularities and to the angle of the incident ultrasound. The complete progression of atherosclerosis may be followed by indices reflecting changes in both the thickness and the surface acoustic properties of the specimen.

Aorta↗
PubMed1985

Angle dependence of ultrasonic backscatter in arterial tissues: a study in vitro.

The object of this study was to obtain quantitative data on the angle dependence of reflected ultrasound signals in freshly excised normal human arterial walls and those with different degrees of atherosclerotic involvement (fatty, fibrofatty, fibrous, or calcified). Fifteen specimens were evaluated in each pathologic subset. The backscatter coefficient (BS, expressed as cm-1 X steradians -1), measured at the single frequency of 10 MHz, was evaluated at a normal angle of incidence of the interrogating beam to the tissue sample and over an angular span of 60 degrees (+/- 30 degrees around normal incidence, 2 degree steps). BS measured at normal incidence separated normal (10(-2) X 0.155 +/- 0.018; mean +/- SE) from fibrofatty (10(-1) X 0.0103 +/- 0.008), fibrous (10(-1) X 0.182 +/- 0.016), and calcified (0.202 +/- 0.016) specimens; normal and fatty (10(-3) X 0.759 +/- 0.142) and fibrofatty and fibrous samples could not be distinguished from each other in a statistically significant way. Angular scattering measurements identified two patterns: A "directive" pattern, characterized by a strongly angle-dependent BS that falls abruptly when the beam is moved slightly away from normal incidence. This pattern was typical of calcified, fibrous, and less markedly, fibrofatty and normal samples. A "nondirective" pattern, characterized by a BS that is not significantly angle dependent and fluctuates throughout the entire angular range. This was typical of fatty samples.

Aorta↗
PubMed1985

Fibrosis, lipids, and calcium in human atherosclerotic plaque. In vitro differentiation from normal aortic walls by ultrasonic attenuation.

This study was designed to determine whether attenuation of ultrasound by the aortic wall is potentially useful in characterizing the atherosclerotic lesion. Measurements were made on fresh specimens taken from a human aorta at autopsy. Four hundred different sites, 4 mm in diameter each, corresponding to the dimension of the ultrasonic beam at the focal zone, were ultrasonically analyzed and histologically studied. Attenuation of ultrasound in each site was assessed by Fourier analysis of the echo produced by a specular reflector placed behind the specimen. Two parameters were measured over the range 7-11 MHz: the integrated attenuation index (per cm), and slope (per cm per MHz) of the best fit straight line relating attenuation and frequency. Histological examination--performed for each of the 400 sites where attenuation had been measured--identified four subsets (100 samples each): normal aortic walls, fibrous plaques, fibrofatty plaques, and calcified plaques. Results obtained from ultrasonic and histological analyses showed that the integrated attenuation index was lowest in normal walls (24 +/- 2.1, mean +/- SE) and progressively increased in fibrous (32 +/- 3.1), fibrofatty (82 +/- 6.5), and calcific (185 +/- 8.7) subsets (all intergroup differences were significant, except for the normal vs. fibrous comparison). The slope value was significantly lower in the fibrous than in the normal subsets: (10(-3)) 31.9 +/- 4.5 vs. (10(-3)) 99.5 +/- 9.1, respectively. Values of fibrofatty and calcific plaques overlapped: (10(-3)) 383 +/- 21 vs. (10(-3)) 320 +/- 23, respectively. Both were significantly different from normal and fibrous groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta↗
PubMed1984

Transient changes in left ventricular mechanics during attacks of Prinzmetal's angina: an M-mode echocardiographic study.

M-mode echocardiograms were recorded in 12 patients with Prinzmetal's angina during 29 episodes of transient myocardial ischemia at rest (18 spontaneous and 11 ergonovine-induced). At peak ST segment elevation a regional mechanical impairment was observed in the interventricular septum during 23 episodes of angina and in the posterior wall during six episodes. In the 18 spontaneous episodes the left ventricular ischemic wall, when compared to the basal state, was found to have a significant reduction in motion (-76.3 +/- 9.1%) (mean +/- SEM), in diastolic thickness (-11.7 +/- 2.5%), and in percent systolic thickening (-88.0 +/- 5.6%). Increase in left ventricular end-diastolic diameter (+13.1 +/- 2.1%) and decrease in percent fractional shortening (-38.1 +/- 3.7%) were also observed. When ST segment was back to the isoelectric line, a transient overshoot in regional left ventricular function was observed. In induced episodes statistically significant changes could be detected by M-mode echocardiography even before appearance of ST segment elevation and anginal pain. No significant difference was found in type or degree of mechanical impairment between induced and spontaneous episodes. Therefore, in patients with Prinzmetal's angina: (1) M-mode echocardiography allows detection of mechanical changes due to transient myocardial ischemia; and (2) mechanical impairment occurs earlier than clinical (pain) and electrocardiographic (ST segment elevation) signs of transmural ischemia.

Adult↗
PubMed1984

Transient changes in left ventricular mechanics during attacks of Prinzmetal angina: a two-dimensional echocardiographic study.

Fifty-five ischemic attacks at rest with ST segment elevation were recorded by two-dimensional echocardiography (2DE) in 20 patients with Prinzmetal angina. Eighteen ischemic attacks were recorded starting from intravenous injection of ergonovine maleate while 37 spontaneous ischemic attacks were recorded from onset of either anginal pain or ECG changes or from the basal state. In each ischemic attack at least one of the following transient alterations was observed by 2DE during ST elevation: (1) Regional hypokinesia, akinesia, or dyskinesia; (2) "step sign," that is, a sharp demarcation between an akinetic or dyskinetic area and an adjacent normal or hypercontracting region; and (3) geometric changes in left ventricular shape, that is, globular appearance in diastole and hourglass silhouette in systole. Regional myocardial asynergy was detected earlier than onset of pain (which was not present in 21 [38%] ischemic episodes) or ST segment elevation on ECG, as documented in 40 ischemic episodes (16 induced and 24 spontaneous) in which echocardiographic monitoring was performed from basal state and carried on up to the appearance of ischemia. All described mechanical changes were fully reversible after pain subsided and ST segment was back to isoelectric, either spontaneously or with nitrates; furthermore, a contractile "rebound phenomenon" of the previously ischemic wall was observed in some episodes. In conclusion, these results outline a role for 2DE in detecting cardiac mechanical impairment due to transient myocardial ischemia with ST segment elevation in humans.

Adult↗
PubMed1983

Different degrees of atherosclerosis detected by backscattered ultrasound: an in vitro study on fixed human aortic walls.

The aim of the study was to establish whether ultrasonic backscattered signals may characterize the atherosclerotic process, providing a quantitative assessment of severity. Measurements on aortic specimens were made in vitro by a transducer acting as transmitter and receiver. Two different indices were measured, one based on peak amplitude value (Vmax) and the other on fast Fourier transform (FFT) analysis of ultrasonic reflected signal (IBI). Two hundred fixed aortic wall specimens (50 normal, 50 fatty streaks, 50 fibrofatty, and 50 calcific) were first characterized ultrasonically and then pathologically, both macroscopically (before ultrasonic study) and histologically (after it). Differentiation of normal, fibrofatty and calcific specimens was achieved using Vmax. Values obtained in fatty streaks overlapped with normal wall but significantly differed from values of fibrofatty and calcific subsets. The results with IBI were similar except that the difference between normal and fibrofatty specimens was not statistically significant. Such changes in acoustic behavior of atherosclerotic walls could be due to increased deposition of highly echogenic biological materials, such as collagen, cholesterol crystals (in fibrofatty specimens), and calcium salts (in calcific ones). Therefore, backscattered signals appear to provide in vitro simple parameters indicative of changes in the arterial wall structure due to the atherosclerotic process.

Aorta↗
PubMed1980

On the role of germ cells in planarian regeneration. II. Cytophotometric analysis of the nuclear Feulgen-DNA content in cells of regenerated somatic tissues.

Previous findings by our group have shown how primordial male germ cells take part in regenerative blastema formation in planarians by migrating to the wound. The role of these cells in rebuilding transected tissues has been investigated in a population of Dugesia lugubris s.l. which is particularly suited for our purpose. In fact, these planarians provide a clear karyological marker to distinguish diploid male germ cells (2n = 8) from tryploid embryonic or somatic cells (3n = 12). In this study we employed the cytophotometric analysis of the nuclear Feulgen-DNA content in order to distinguish non-replicating male germ cells from reserve and somatic cells. The Feulgen-DNA content in cells from the gonad-free caudal area was measured after complete regeneration. Most non-replicating cells (94-95%) were found to have a DNA amount typical of cells previously estimated as triploid. Some (5-6%) nuclei containing a DNA amount typical of cells previously estimated as diploid male gonia were also found. These findings seem to support the view that primordial male germ cells also participate in rebuilding somatic tissues according to the field influence they encounter during regeneration. The possibility that metaplasia (or cell transdifferentiation) may occur in planarians is finally discussed.

Animals↗
PubMedDate not supplied

In vivo radiofrequency ultrasound analysis of normal human heart structures.

Twenty young subjects were studied with a microprocessor system for quantitative analysis of backscattered radiofrequency (RF) signals from normal heart structures. This system allows an "on line" quantitative evaluation of the amplitude of the RF "native" signal, before the chain of processing and display, with the acquisition gate displayed on a conventional M-mode machine. Septum, posterior wall, and anterior mitral leaflet were analyzed. The gate length was kept at 3 microseconds (2.35 mm) for the ventricular walls (excluding endo- and epicardial reflections), and at 1 microsecond (0.8 mm) for the mitral valve. Integrated backscatter index (IBI) was calculated as the time integral of [u(t)[, where u(t) = i(t) X s(t); is the time sequence of backscattered echoes and s(t) is the time gate delimiting the thickness of the insonated tissue. The IBI was expressed in percent, normalized for the pericardial interface (the strongest reflection was assumed to be 100%). The percent IBI for the septum was found to be 22 +/- 4%; for the posterior wall it was 17 +/- 3%; for the anterior mitral leaflet it was 5 +/- 2%. A second reading of the same structures was performed by the previous observer and by a new one. Good intraobserver (r = 0.92) and interobserver (r = 0.88) correlations were obtained. In conclusion, a regional variation in echo amplitude from different heart structures can be observed in man. This set of values can be used as normal values for future studies in pathologic conditions.

Adult↗