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Biomedical subjects

F Lombardi

Publications and source records attributed to F Lombardi.

At least 163 records · Page 9Linked to original sources
PubMed1987

Antigenic and biochemical characterization of poliovirus type 2 isolated from two cases of paralytic disease.

Three isolates of poliovirus type 2 were obtained from rectal and pharyngeal swabs of two patients with paralytic poliomyelitis from Southern Italy (1981/1983). Neither one of the patients had received oral poliovirus vaccine, although a systematic vaccination campaign is conducted in the area. Neutralization tests with strain-specific antisera and analysis of the structural proteins by SDS-PAGE indicated that the three isolates were typical Sabin-like poliovirus type 2. Moreover, neutralization assays by means of a panel of well-characterized monoclonal antibodies indicated that the three isolates carried an antigenic mosaic where both wild-type and Sabin-specific epitopes were represented. The T1 fingerprints of the RNA of the three isolates diverged slightly from the standard Sabin reference map. A comparison of the oligonucleotide fingerprints of the viruses isolated from the pharynx and the feces of one patient indicated that mutations appeared as early as during replication in the intestinal tract.

Antibodies, Monoclonal↗
PubMed1987

[Non-invasive evaluation with continuous Doppler of the systolic pressure of the right ventricle in patients with tricuspid insufficiency].

Tricuspid regurgitation (TR) is detected by Doppler echocardiography in a high proportion of patients with right ventricle pressure or volume overload. Continuous wave Doppler (CW) provides a noninvasive estimation of the transtricuspid systolic pressure gradient, applying the modified Bernoulli formula to the maximum velocity of the TR jet. The purpose of this study was to test the accuracy of the CW prediction of systolic right ventricular pressure (RVPs), obtained adding a clinical estimate of the mean right atrial pressure (RAPm) to the Doppler derived pressure gradient. The study population consisted of 22 adult patients with Doppler proved TR, undergoing right heart catheterization (cath) for mitral valve disease (12 pts), atrial septal defect (8 pts), dilated cardiomyopathy (1 pt) or pulmonary hypertension (1 pt). Two studies were duplicated after nifedipine administration. TR was graded by pulsed Doppler flow mapping as mild in 7, moderate in 11, severe in 4 pts. RAPm was estimated clinically from the inspection of neck veins pulsatility (mmHg = pulsatility cm+5/1.3). At CATH RVPs ranged from 27 to 80 (46 +/- 17) mmHg, RAPm from 0 to 13 (6 +/- 3) mmHg. RVPs Doppler prediction showed a close correlation with CATH (r .97, SEE 4.2 mmHg), with a slight mean underestimation (-2 +/- 4 mmHg) (Fig. 3, Tab. I). The discrepancies between CW and CATH ranged from -9 to +10 mmHg, almost entirely due to inaccuracy of the RAPm clinical estimate (r .48, see 3.8 mmHg) (Fig. 4, Tab. I).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Daily reproducibility of electrophysiologic test results in malignant ventricular arrhythmia.

The reproducibility of electrophysiologic testing on successive days was assessed in the absence of antiarrhythmic drug treatment. Forty-two patients, 17 with compromising ventricular tachycardia and 25 with ventricular fibrillation unrelated to myocardial infarction, underwent 2 baseline studies. During the first electrophysiologic study, arrhythmia was induced in 32 of 42 patients (76%); however, during the second study a similar endpoint was reached in only 22 patients (52%) (chi 2 = 5.12, p less than 0.05). Only 18 of the 32 patients (56%) with induced arrhythmia during the first study had a reproducible result. Reproducibility was not related to presence of coronary artery disease, nature of presenting arrhythmia, or endpoint achieved (sustained or nonsustained ventricular tachycardia) during electrophysiologic study. Hence, reproducibility of endpoint during electrophysiologic investigation should be ascertained in each patient before initiating serial drug studies.

Adolescent↗
PubMed1986

Spectral and cross-spectral analysis of heart rate and arterial blood pressure variability signals.

A parametric method for autoregressive (AR) auto- and cross-spectral analysis is presented for the contemporaneous processing of heart rate and arterial blood pressure variability signals. In particular, the introduced bivariate spectral analysis (phase and coherence spectra) provides quantitative and objective means which are useful to measure the role played by the neural controlling systems (sympathetic and parasympathetic systems) on the cardiovascular signals under different pathophysiological conditions. Algorithmic aspects, connected to the way of processing discrete numerical series synchronized to single cardiac beats, are particularly stressed. Important applications are foreseen both in physiological studies and in clinical practice as an aid to the detection of various relevant cardiovascular pathologies such as hypertension and diabetes.

Blood Pressure↗
PubMed1986

Lack of association between prodromes nausea and vomiting, and specific electrocardiographic patterns of acute myocardial infarction.

We conducted an observational study on 164 patients consecutively admitted to our coronary care unit in order to evaluate the predictive role of cardiac prodromes nausea and vomiting, in distinguishing a particular electrocardiographic pattern (Q wave versus non-Q wave and localisation) of an acute myocardial infarction. Patients with the prodromes made up 47.0% of all Q wave myocardial infarction and 59.4% in those without Q wave myocardial infarction. Furthermore, patients had nausea and vomiting in 25.0% of all Q wave myocardial infarction and in 31.2% of all non-Q wave infarction. No significant differences were found in the patients who experienced nausea and vomiting in the localisation (anterior versus inferior) of myocardial infarction. Our findings indicate that the cardiac prodromes of nausea and vomiting do not play any particular role in predicting a specific electrocardiographic pattern of acute myocardial infarction.

Electrocardiography↗
PubMed1986

Continuous recording of direct high fidelity arterial pressure and electrocardiogram in ambulant patients.

A system providing high quality direct arterial blood pressure recordings and electrocardiograms in ambulatory patients was devised using a modified commercially available Holter type magnetic tape recorder together with a microminiature Millar (3F) tip transducer. This system did not require a perfusion line and solved the major drawbacks of other available systems. Pressure and electrocardiographic data were fed directly from the playback unit into a minicomputer for automatic beat to beat waveform analysis. Thus the blood pressure and RR interval variability signals could be simultaneously analysed with autoregressive modelling techniques to provide a quantitative estimate of sympathovagal balance in ambulant patients. The system was reliable, simple, and safe to use.

Ambulatory Care↗
PubMed1986

Effects of propranolol on the impulse activity of cardiovascular sympathetic afferent fibers.

The influence of beta-adrenergic receptor blockade on the impulse activity of 21 cardiovascular sympathetic afferent nerve fibers (11 from the thoracic aorta, 10 from the pulmonary veins), isolated from the left sympathetic rami communicantes T-3 and T-4 was studied in anesthetized, vagotomized cats. Aortic pressure, heart rate, and neural discharge were recorded during control conditions and during brief aortic occlusions of comparable amplitude and duration. Administration of dl-propranolol (0.2-0-4 mg/kg) did not modify aortic pressure or neural discharge of the fibers during control conditions, although, as expected, heart rate was diminished. dl-Propranolol administration did change the response of cardiovascular sympathetic afferents to similar aortic pressure increases. Before drug administration, aortic occlusion caused a significant increase in neural discharge of both aortic and pulmonary vein sympathetic afferent fibers, from 0.52 +/- 0.12 to 1.64 +/- 0.31 and from 0.67 +/- 0.10 to 2.08 +/- 0.25 impulses/sec, respectively (p less than 0.05). After dl-propranolol administration, comparable increases in aortic pressure resulted in slight but not significant increases in neural discharge of aortic and pulmonary vein fibers. Administration of d-propranolol (0.4-0.6 mg/kg), which possesses only membrane-stabilizing properties, did not modify the firing rate of four pulmonary sympathetic afferents, which subsequently decreased their response to pressure rises after administration of dl-propranolol. These results indicate that beta-adrenergic receptor blockade reduces the responsiveness to hemodynamic stimuli of sympathetic cardiovascular afferent fibers that are capable of mediating excitatory pressor reflexes.

Animals↗
PubMed1986

Power spectral analysis of heart rate and arterial pressure variabilities as a marker of sympatho-vagal interaction in man and conscious dog.

In 57 normal subjects (age 20-60 years), we analyzed the spontaneous beat-to-beat oscillation in R-R interval during control recumbent position, 90 degrees upright tilt, controlled respiration (n = 16) and acute (n = 10) and chronic (n = 12) beta-adrenergic receptor blockade. Automatic computer analysis provided the autoregressive power spectral density, as well as the number and relative power of the individual components. The power spectral density of R-R interval variability contained two major components in power, a high frequency at approximately 0.25 Hz and a low frequency at approximately 0.1 Hz, with a normalized low frequency:high frequency ratio of 3.6 +/- 0.7. With tilt, the low-frequency component became largely predominant (90 +/- 1%) with a low frequency:high frequency ratio of 21 +/- 4. Acute beta-adrenergic receptor blockade (0.2 mg/kg IV propranolol) increased variance at rest and markedly blunted the increase in low frequency and low frequency:high frequency ratio induced by tilt. Chronic beta-adrenergic receptor blockade (0.6 mg/kg p.o. propranolol, t.i.d.), in addition, reduced low frequency and increased high frequency at rest, while limiting the low frequency:high frequency ratio increase produced by tilt. Controlled respiration produced at rest a marked increase in the high-frequency component, with a reduction of the low-frequency component and of the low frequency:high frequency ratio (0.7 +/- 0.1); during tilt, the increase in the low frequency:high frequency ratio (8.3 +/- 1.6) was significantly smaller. In seven additional subjects in whom direct high-fidelity arterial pressure was recorded, simultaneous R-R interval and arterial pressure variabilities were examined at rest and during tilt. Also, the power spectral density of arterial pressure variability contained two major components, with a relative low frequency:high frequency ratio at rest of 2.8 +/- 0.7, which became 17 +/- 5 with tilt. These power spectral density components were numerically similar to those observed in R-R variability. Thus, invasive and noninvasive studies provided similar results. More direct information on the role of cardiac sympathetic nerves on R-R and arterial pressure variabilities was derived from a group of experiments in conscious dogs before and after bilateral stellectomy. Under control conditions, high frequency was predominant and low frequency was very small or absent, owing to a predominant vagal tone. During a 9% decrease in arterial pressure obtained with IV nitroglycerin, there was a marked increase in low frequency, as a result of reflex sympathetic activation.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenergic beta-Antagonists↗
PubMed1986

Circulatory markers of nervous activation during myocardial ischemia.

In man, electrocardiographic changes typical of transient myocardial ischemic episodes can be accompanied by increases in arterial pressure and heart rate or, at the opposite side of the spectrum, by decreases in arterial pressure and heart rate. It has been clearly proved that all of these changes can occur independently of the perception of pain. Transient ischemic episodes associated with hypotension and bradycardia or hypotension without the tachycardia that could be expected from a baroreceptive mechanism, are likely to reflect a depressor reflex mediated by cardiac vagal afferent fibers. It is a clinical and experimental working hypothesis that these depressor reflexes would characterise more severe episodes of ischemia: in clinics, those accompanied by signs of acute ventricular failure; in the laboratory, those induced by "global" ischemia. On the other hand, ischemic episodes associated with hypertension and tachycardia, usually thought to depend on a pain mechanism, are likely to reflect a pressor reflex mediated by cardiac sympathetic afferent fibers. It is our hypothesis that these pressor reflexes from the heart are the most frequent companions of less severe ischemic episodes, whether or not signalled by anginal pain. In the laboratory, a pressor reflex can be constantly obtained with a limited "regional" ischemia. These neural mechanisms, that should be analyzed independently of any teleologic reasoning, may be of paramount importance not only in determining the hemodynamic profile accompanying ischemic episodes, but in inducing those local changes in visceral neural activity that an increasing evidence indicates as crucial factors in arrhythmias and coronary death.

Angina Pectoris↗
PubMed1985

Combination of mitomycin C + etoposide in advanced gastric carcinoma.

In June 1981 the authors activated a trial to evaluate the therapeutic effectiveness of the combination mitomycin C (MMC) + etoposide (VP 16) in previously untreated gastric carcinoma with measurable neoplastic lesions. Drugs were administered according to the following schedule: MMC, 12 mg/m2 i.v. day 1, + VP 16, 150-200 mg/m2 orally days 2, 3, 4, 22, 23, 24 every 6 weeks. The response rate (CR+PR) was 16.7%, which is not higher than that obtained when MMC and VP 16 are used as single agents. Overall median survival (8 months) was similar to that reported in the recent literature with combination chemotherapy.

Adult↗
PubMed1985

Aggravation of arrhythmia induced with antiarrhythmic drugs during electrophysiologic testing.

There is evidence that antiarrhythmic drugs can worsen ventricular arrhythmias in patients. In a previous study ventricular arrhythmias worsened 11% when noninvasive monitoring and exercise tests were performed to evaluate drug effect. How frequently this complication occurs when patients undergo electrophysiologic studies is not known. Electrophysiologic (EP) tests were carried out in 63 patients who had a history of malignant, sustained ventricular tachyarrhythmias. Monitoring and exercise tests showed low-frequency or nonreproducible ventricular arrhythmia. Criteria for definite drug-induced aggravation of arrhythmia included conversion of nonsustained ventricular tachycardia to a sustained ventricular arrhythmia and provocation of the end point with one extrastimulus when three were required during control. Aggravation was deemed possible when, as compared to a control group, the end point resulted with the use of one less extrastimulus and sustained tachycardia with a more rapid rate was provoked. A total of 216 single drug studies were performed (3.4/patient). In general, definite or possible aggravation occurred in 35 tests (16%). In 28 cases (12.9%) aggravation was categorized as definite, while in 7 cases (3.2%) the induced arrhythmia was deemed as possibly related to the use of the antiarrhythmic drugs. Drug tests with multiple agents caused aggravation of arrhythmia in 19 patients (30%). Therefore, exacerbation of arrhythmia by antiarrhythmic drugs also occurs during electrophysiologic study. The incidence approximates that reported when monitoring and exercise tests are used for evaluating drug efficacy.

Anti-Arrhythmia Agents↗