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Biomedical subjects

M Penco

Publications and source records attributed to M Penco.

80 records · Page 5Linked to original sources
PubMedDate not supplied

The relevance of malondialdehyde as a biochemical index of lipid peroxidation of postischemic tissues in the rat and human beings.

By using a recently developed ion-pairing high-performance liquid chromatographic method for the direct determination of malondialdehyde (MDA) and several other acid-soluble low-mol-wt compounds (ascorbate, oxypurines, nucleosides, nicotinic coenzymes, high-energy phosphates), the variations of tissue and plasma MDA as a function of ischemia and reperfusion were determined in the rat (isolated Langendorff-perfused hearts and short-term incomplete cerebral ischemia) and in human beings (patients suffering from acute myocardial infarction subjected to fibrinolysis). In the rat, the data obtained indicate that, contrary to what had been previously reported in literature, MDA is not present either in control heart or in control brain. Oxygen deprivation induces the production of a low, but detectable amount of MDA in both heart and brain, whereas reperfusion causes a marked increase of MDA in both tissues. In human beings, plasma MDA was deeply affected only in patients suffering from acute myocardial infarction with successful thrombolysis, thus indicating the occurrence of oxygen radical-mediated tissue injury also in humans. On the whole, these results suggest that MDA is a valid biochemical marker of lipid peroxidation of postischemic tissues, which however needs a reliable analytical technique for its determination.

Analysis of Variance↗
PubMedDate not supplied

Assessment of diastolic left ventricular filling by echocardiographic automated border detection and comparison with radionuclide ventriculography.

To determine whether indexes obtained from a newly developed echocardiographic automated border detection (ABD) technology provide a reliable estimate of left ventricular (LV) diastolic filling, ABD variables of LV filling were compared with volumetric measurements determined by radionuclide angiography. Forty-two patients with a variety of heart diseases (age range, 11 to 76 years) underwent ABD echocardiographic studies on the same day as the radionuclide examination. Technically adequate ABD data could be obtained in 31 patients (74%). Nineteen healthy subjects served as normal controls. Area-time and volume-time waveforms for echocardiographic measurements were obtained from LV short-axis views at the level of the papillary muscles and four-chamber apical views. Both the diastolic indexes derived from the waveform of area change (short-axis view) and volume change (four-chamber apical view) correlated with radionuclide variables. Values measured from the ABD area-time waveform showed the following correlations: peak filling rate (r = 0.86; standard error of the estimate [SEE] = 0.62), time to peak filling rate (r = 0.85; SEE = 23.11), rapid filling phase fractional change (r = 0.79; SEE = 5.51), and atrial filling phase fractional change (r = 0.71; SEE = 5.82). Correlations of indexes derived from the ABD volume-time waveform were as follows: peak filling rate (r = 0.87; SEE = 0.50), time to peak filling rate (r = 0.90; SEE = 22.03), rapid filling fractional change (r = 0.83; SEE = 5.33), and atrial filling fractional change (r = 0.77; SEE = 4.68). ABD LV filling parameters in patients with heart disease and normal control subjects were significantly different. Thus ABD data from short-axis and apical views have a strong linear relation with radionuclide ventriculographic measurements and may be used as a method to assess LV diastolic filling.

Adolescent↗
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PVF velocity pattern in patients with heart failure: transesophageal echocardiographic assessment.

In order to assess the role of the pulmonary venous flow (PVF) velocity pattern in the evaluation of patients with congestive heart failure (CHF), we studied 41 CHF patients by means of transthoracic echocardiography (TTE) and multiplane transesophageal echocardiography (TEE). The etiology of CHF was idiopathic or ischemic dilated cardiomyopathy in 19 patients and hypertensive heart disease in 22. Sixteen subjects without cardiovascular disease were selected as normal controls. PVF peak systolic and peak early diastolic (D) velocities were recorded by TEE and TTE and the systolic fraction (SF) was measured (i.e., the systolic velocity-time integral-VTI-expressed as a fraction of the sum of systolic and early diastolic (VTI). TEE tracings were obtained in all patients and had more laminar-appearing spectral signals, thus were used for analysis. By TEE the mitral flow velocity patterns were also evaluated: peak early diastolic velocity (E), peak velocity at atrial contraction, E velocity normalized for VTI (E/VTI), deceleration time (DT), and left ventricular isovolumic relaxation time (LVIRT). The left ventricular ejection fraction (LVEF) was calculated by two-dimensional echocardiographic images using the modified Simpson method. The SF was lower in CHF patients as compared with normal controls (p < 0.0001). The E/VTI ratio was higher, and DT and LVIRT were shorter (p < 0.0001) in CHF patients. A significant correlation was observed between SF and LVEF in CHF patients (r = 0.76, p < 0.001). Two different PVF velocity patterns (type A:SF << 50%, D > 50 cm/s; type B:SF approximately 50%, D > 50 cm/s) were recognized in patients with a low LVEF (type A) and a nearly normal or normal LVEF (type B). Patients with LVEF < 40% showed mean SF values significantly lower than patients with LVEF > 40% (33.26 +/- 10.84 vs. 51.00 +/- 4.00%, p < 0.0001). Mean DT and LVIRT values were not significantly different in patients with LVEF < 40% and > 40%. Thus in CHF patients TEE PVF velocity patterns help in distinguishing patients with systolic dysfunction (low LVEF and SF) from patients with predominant diastolic impairment (normal or nearly normal LVEF, high D velocities).

Adult↗
PubMedDate not supplied

Chlamydia pneumoniae infection in patients with acute coronary syndrome: a clinical and serological 1-year follow-up.

The role of Chlamydia pneumoniae infection in pathogenesis and prognostic stratification of patients with acute coronary syndromes is still unclear. However, a limitation of many studies is the evaluation of the long-term prognostic role of a sample obtained during the acute phase, whereas the assessment of the temporal trend of antibody titers could be more useful. One-hundred and fourteen consecutive patients with acute coronary syndromes (71 with acute myocardial infarction and 43 with unstable angina) were studied. Blood samples were obtained immediately after hospital admission and 1, 3, 6 and 12 months after the acute event. The microimmunofluorescence test was used to detect C. pneumoniae specific antibodies. The incidence of new coronary events (death, myocardial infarction, recurrent angina) was recorded during the 1-year follow-up period. No significant difference was found between patients with (n = 35) or without (n = 79) new coronary events (N.C.E.) regarding baseline and serial values of C. pneumoniae antibodies. The rate of high titers at any time of follow-up was also similar in the two groups: IgG > or =1:512 were present in 52%, 64%, 55% and 32% of N.C.E.+ patients, and in 48%, 54%, 52% and 36% of N.C.E.- patients at 1, 3, 6 and 12 months respectively; IgA > or =1:256 were present in 26%, 23%, 30% and 23% of N.C.E.+ patients and in 20%, 30%, 25% and 19% of N.C.E.- patients at 1, 3, 6 and 12 months respectively. Our data indicate that elevated titers of C. pneumoniae antibodies, even with a serial 1-year evaluation, are not a predictor of future coronary events in patients with acute myocardial infarction or unstable angina.

Angina, Unstable↗
PubMedDate not supplied

[Diagnostic and therapeutic strategies in post-infarct].

It is of primary importance for the clinical cardiologist to keep in mind the parameters allowing an adequate prognostic stratification in post-infarct patients in view of making the best diagnostic and therapeutic choices. A diagnostic strategy, based on a pathophysiologic approach, should evaluate four aspects: spontaneous and stress-induced ischemia, myocardial viability, and ventricular arrhythmias. Spontaneous ischemia has an undefined prognostic value, especially in the thrombolytic era; therefore it seems reasonable to perform invasive procedures in patients who are not stabilized by an adequate medical therapy or with large jeopardized areas. In asymptomatic patients, a provocative stress test allows a more articulated decisional iter. It is preferably to perform the test by the most physiological exercise EKG, together with the echocardiographic imaging, after the acute phase. It has a high negative predictive value, but a low positive predictive value. The detection of myocardial viability is frequently performed, mainly in patients with large post-ischemic myocardial dysfunction. Among all the proposed methods, the echo-dobutamine test mainly allows to estimate patients in whom revascularization may result in more benefit. The role of ventricular arrhythmias as an independent prognostic factor is debated and has to be always considered in relationship to other parameters, particularly left ventricular function. Regarding the therapeutic strategy, the indications from recent trials, related to antithrombotic drugs, beta-blockers, ACE-inhibitors, nitrates, Ca-blockers and antiarrhythmic drugs, are emphasized.

Adrenergic beta-Antagonists↗