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Biomedical subjects

S Lenzi

Publications and source records attributed to S Lenzi.

At least 19 recordsLinked to original sources
PubMed2006

Transition probabilities in 134Pr: a test for chirality in nuclear systems.

Exited states in 134Pr were populated in the fusion-evaporation reaction 119Sn(19F,4n)134Pr. Recoil distance Doppler-shift and Doppler-shift attenuation measurements using the Euroball spectrometer, in conjunction with the inner Bismuth Germanate ball and the Cologne plunger, were performed at beam energies of 87 MeV and 83 MeV, respectively. Reduced transition probabilities in 134Pr are compared to the predictions of the two quasiparticle + triaxial rotor and interacting boson fermion-fermion models. The experimental results do not support the presence of static chirality in 134Pr underlying the importance of shape fluctuations. Only within a dynamical context the presence of intrinsic chirality in 134Pr can be supported.

Journal Article↗
PubMed2000

Endogenous digitalislike factors in obstructive sleep apnea.

Recent studies have provided evidence that hypoxia may stimulate the release of endogenous digitalislike factors (EDLF). Obstructive sleep apnea (OSA) is characterized by intermittent hypoxia during sleep and may be associated with sympathetic activation and a high risk of developing hypertension. This study was designed to measure EDLF in the plasma of patients with OSA diagnosed by polysomnography, with patients being classified by the number of apneic-hypopneic episodes/h sleep (apnea-hypopnea index, AHI). Plasma was obtained in the morning from 8 male normotensive OSA patients (OSA-N) (AHI 70+/-6), 2 untreated hypertensive OSA patients (OSA-HT), and 11 age-matched healthy male controls (C). EDLFs of different hydrophobicities were separated from the same plasma sample by solid-state C18-cartridges with 25% acetonitrile (ACN) (EDLF-1) followed by 40% ACN (EDLF-2). This procedure recovered ouabain in the first fraction and digoxin and digoxigenin in the second. EDLF was quantified in pM ouabain-equivalents by a human placenta radioreceptor assay. EDLF-1 levels were similar for OSA-N and C (231+/-55 vs. 258+/-58), whereas EDLF-2 levels were increased in OSA-N (244+/-51 vs. 110+/-25 in C, p=0.02). Norepinephrine was increased in apneics. The two OSA-HT had EDLF and norepinephrine levels similar to OSA-N. These preliminary results suggest that OSA is associated with an increase in the more hydrophobic EDLF levels in both normotensive and hypertensive states. No significant increase was found for the less hydrophobic ouabain-like EDLF.

Adult↗
PubMed1998

[The role of LDL in the origin and progression of atherosclerosis: pathobiological concepts on the origin and development of atherosclerotic lesions and the role of the endothelium].

The existence of a causal relation between elevated cholesterol levels and atherosclerosis is now considered an established fact, while cellular and molecular mechanisms underlying this relationship begin only now to be unravelled. The first stage of atherosclerosis development is the fatty streak, a focal accumulation of blood-derived lipid-laden macrophages in the arterial intima. The endothelium, which plays a pivotal role in vascular homeostasis, undergoes major functional changes under the influence of "oxidized" and "minimally-modified"-LDL, able to promote "endothelial activation", with the expression of adhesion molecules and chemoattractants for monocytes. Endothelial activation seems to be the transducer of atherogenic signals in the first stages of development of atherosclerosis. LDL also play a further crucial role in the progression and the instabilization of the plaque, and in the pathogenesis of functional changes of vasomotor tone.

Adolescent↗
PubMed1998

[Prevention and therapy of vascular damage and endothelial dysfunction with hypocholesteremic agents].

Several recent pieces of clinical evidence have demonstrated that reduction of cholesterol levels positively affects outcomes in both primary and secondary prevention of atherosclerotic vascular disease. The mechanism for the beneficial effects of cholesterol-lowering interventions has been attributed to decreased progression or actual regression of plaques as a consequence of reduced circulating LDL concentrations. Other mechanisms can be hypothesized, including a "stabilizing" effect on plaques, which would decrease chances of rupture, and an improvement of endothelial dysfunction, which would slow-down the progression of the disease. This review is aimed at offering an update on such mechanisms. The hypothesis of a direct action of cholesterol-lowering agents, in particular of statins, on endothelial functions, independently of LDL-lowering effects, will be discussed.

Anticholesteremic Agents↗
PubMed1996

Increased mutagen-induced chromosome damage in patients with transformed laryngeal pre-cancerosis.

Factors that contribute to malignant transformation of laryngeal pre-neoplastic lesions remain largely unknown. Potential etiological factors may be related to a genetically controlled sensitivity to environmental carcinogens. In this study, we investigated bleomycin-induced chromosome damage in 15 patients who experienced a malignant transformation of preneoplastic laryngeal lesions during follow-up, as compared with chromosome fragility in 30 historical controls with no progression of keratoses during a 10-year follow-up, in a match-paired analysis. Chromosomal analysis demonstrated higher sensitivity to clastogens in patients with malignant progression of laryngeal pre-neoplastic lesions than that of control patients with no evolution of their original laryngeal keratoses (p = 0.003). Furthermore, among the study patients, chromosome sensitivity was most apparent in non-tobacco users with malignant transformation of laryngeal disease. Our data suggest that subjects with pre-neoplastic laryngeal lesion showing increased susceptibility to carcinogens could be at higher risk for development of laryngeal carcinoma.

Adult↗
PubMed1996

Omega-3 fatty acid supplementation and lipoprotein(a) concentrations in patients with chronic glomerular diseases.

Renal disease patients often exhibit alterations in the lipid profile which may become an important risk of accelerated atherosclerosis and contribute to disease progression. Among such alterations, increased levels of lipoprotein(a) [Lp(a)] are common and may be related, in part, to the degree of proteinuria. Omega-3 polyunsaturated fatty acids (omega-3 FA) have been reported to decrease Lp(a) concentrations in nonrenal subjects. In addition, they have recently been shown to reduce proteinuria in patients with chronic glomerular disease. We therefore tested the hypothesis that omega-3 FA treatment in patients with chronic glomerular disease may reduce Lp(a) concentrations. Eight patients (2 with membranous glomerulonephritis, 6 with focal glomerular sclerosis) were submitted to a total of 13 six-week courses of treatment with omega-3 FA, at a dose of 3 g/day with a triglyceride preparation (n = 4) and of 7.7 g/day with an ethyl-ester preparation (n = 9). Both treatments significantly increased the proportions of omega-3 to omega-6 FA in total serum lipids, documenting compliance to treatment. Both treatments were also effective in decreasing serum thromboxane (from mean 490 +/- (SEM) 70 to 325 +/- 49 ng/ml, p < 0.05, in the high-dose group) and prolonging the bleeding time (from 5.8 +/- 0.4 to 7.7 +/- 0.5 min, p < 0.05, in the high-dose group), thus documenting the biological efficacy of treatment. However, despite a significant reduction in serum triglyceride levels (from 137 +/- 20 to 104 +/- 19 mg/dl in the high-dose group), Lp(a) concentrations did not change (292 +/- 120 U/l before, 315 +/- 130 U/l after the high-dose therapy). Treatment-related changes in proteinuria (from 2.9 +/- 0.5 to 2.1 +/- 0.7 g/24 h) were not related at all to changes in Lp(a) levels. We conclude that omega-3 FA do not decrease Lp(a) concentrations in renal patients with chronic glomerular diseases and that Lp(a) levels are unlikely to be related to the degree of proteinuria within the short-term modifications induced by omega-3 FA.

Adult↗
PubMed1996

[Lipoprotein(a) as an athero-thrombotic risk factor: epidemiologic evidence and possible pathogenetic mechanisms].

Lipoprotein (a) [Lp(a)] has been known for more than 20 years as a peculiar "variant" of low-density lipoproteins (LDL), the recent interest for which mostly derives from its epidemiological and maybe pathogenetic link with coronary artery disease and atherosclerosis. The protein moiety of Lp(a)-apo(a)-is a glycoprotein produced by the liver, with evident structural analogies with plasminogen. A large variety of apo(a) isoforms have been described, with large variability in molecular weight, encoded by alleles located on chromosome 6. Plasma concentrations of Lp(a) are largely genetically determined, but variations on these levels are induced by changes in hepatic synthesis due to changes in control factors (for example in proteinuric syndromes). Many-but not univocal-epidemiological pieces of evidence indicate that high plasma concentrations of Lp(a) are associated with atherosclerosis and its cardiac, cerebral and peripheral manifestations, thereby potentially identifying a new cardiovascular risk factor, independent from plasma concentrations of LDL. This review will discuss such evidence and the mechanisms potentially linking Lp(a) and atherosclerosis. Proposed mechanisms include, among others, the susceptibility of Lp(a) to oxidation, the interference with mechanisms of fibrinolysis and the induction of endothelial activation.

Arteriosclerosis↗
PubMed1995

p53 oncoprotein overexpression correlates with mutagen-induced chromosome fragility in head and neck cancer patients with multiple malignancies.

In this study, we analysed immunocytochemically p53 expression in first primary and second primary cancers from 25 head and neck cancer patients (HNCPs) with multiple malignancies in comparison with oncoprotein expression in tumour tissues from 25 historical HNCP controls with single cancer in a match-paired analysis. Moreover, we investigated bleomycin-induced chromosome fragility in both groups of HNCPs and in 21 additional healthy controls. Thirty-nine out of 75 tumour specimens analysed (52%) showed positive p53 immunostaining. Eleven out of 25 (44%) from single cancer patients and 28 out of 50 (56%) tumours from HNCPs with multiple malignancies were p53 positive. In the group of multiple primary cancers, nine patients (36%) showed positive staining of both first and second primaries, whereas six (24%) had positive labelling of first primary cancer but not of the subsequent second primary, four (16%) patient showed p53 expression only in the second primary cancer and six (24%) patients showed no p53 immunoreactivity in both tumours. Chromosomal analysis demonstrated a higher sensitivity to clastogens of HNCPs with multiple tumours than of HNCPs with a single cancer (P < 0.01), and a significant correlation between chromosome fragility and p53 overexpression (P < 0.01) only in HNCPs with multiple malignancies more than in those with single head and neck cancer (P = 0.11). Moreover, we found that patients with p53-positive staining of both first and second primaries showed a statistically significant higher mutagen sensitivity than those with a single p53 immunoreactive tumour or those in whom both cancers were p53 negative (P < 0.01). Our data suggest that subjects with increased susceptibility to carcingogens after exposure to tobacco or alcohol are at higher risk for multiple cancers in which one of the most common genetic events is aberrant p53 expression.

Aged↗
PubMed1990

[Atrial natriuretic factor in physiological conditions and pathological states].

Having outlined the principal physiological and pathological aspects of the atrial natriuretic factor (ANF) on the basis of data found in the literature, the authors report the results of their research on variations of ANF plasma level during hyperkinetic atrial arrhythmia, acute myocardial infarction with and without complications as well as hypotensive and renal effects of synthetic ANF in congestive heart failure. Regardless of the cause of hyperkinetic atrial arrhythmia, high ANF levels were normalized or significantly reduced after the return to sinus rhythm whereas with the sole reduction of ventricular rate ANF remained raised. In uncomplicated myocardial infarction ANF level was raised to an extent inversely proportional to the ejection fraction. In cardiogenic shock, ANF values were high and correlated to the high central venous pressure and heart rate. On the contrary, in the hypotensive bradycardia syndrome ANF values were normal even when the syndrome had occurred in the acute stage of infarction. In congestive heart failure, ANF administration had contradictory effects in that diuresis was induced by lower doses, and hypotension by higher ones.

Animals↗
PubMed1989

Cancer mortality among workers in the Tuscan tanning industry.

The mortality of 2926 male workers at the tanneries in the "leather area" of Tuscany was examined from 1950 to 1983 comparing it with the national mortality. Cancer mortality was of particular concern because of the many chemicals known to be definite or suspected carcinogens used in the tanning cycle, in particular chromate pigments, benzidine based dyes, formaldehyde, and organic solvents. There was no excess of deaths for cancers of all sites but slight increases in deaths from cancer of the lung (SMR = 131, CI 95% = 88-182), bladder (SMR = 150, CI 95% = 48-349), kidney (SMR = 323, CI 95% = 86-827), pancreas (SMR = 146, CI 95% = 39-373), and leukaemias (SMR = 164, CI 95% = 53-382) occurred. Two cases of soft tissue sarcomas were observed versus 0.09 expected (SMR = 2178, CI 95% = 250-8023).

Adult↗
PubMed1989

[Abnormal coronary response to vasomotor stimuli: analogies between variant angina and X syndrome].

The aim of this study was to evaluate the effects of hyperventilation (HV) and of ic nitroglycerin (NTG) on coronary diameters and hemodynamics in 32 patients with angina pectoris. Of these, 10 patients had stable angina and critical coronary artery disease (CAD, Group I), 12 patients with variant angina (VA) and no or minor coronary atherosclerosis (Group II), and 10 patients with angina and normal coronary arteries (syndrome X (SX), Group III). All patients underwent coronary angiography as well as right heart catheterization; measurements of left anterior descending coronary diameters (mid segment), great cardiac vein blood flow, aortic pressure and coronary resistance were performed on baseline, after HV and following NTG. HV caused coronary spasm in 4 patients with VA and significantly (p less than 0.001) reduced coronary diameters and regional blood flow both in Groups II and III, but not in Group I. NTG resulted in increased coronary diameters in all patients, however variations were greater in VA and SX (44 and 39%, respectively) than in Group I (18%; p less than 0.025). NTG induced an increase of coronary blood flow only in patients with CAD. We conclude that patients with VA and SX present a similar coronary response to vasomotor stimuli, either after HV or following NTG. Response is abnormal if compared to that of patients of group I, and it involves both epicardial and intramural coronary vessels. Thus, we suggest that SX and VA belong to a single pathogenetic entity with a spectrum of clinical manifestations.

Adult↗
PubMed1987

Increased permeability of hamster microcirculation to glycosylated albumin.

The permeability of the microcirculation to native and glycosylated albumin was tested in 25 non-diabetic Syrian hamsters. The microvasculature of the cheek pouch was studied by a fluorescent video-microscopy technique after the animals had been injected with fluorescent native or glycosylated albumin or with both. Native albumin remained in the cheek pouch microvasculature, whereas glycosylated albumin leaked out of the microvascular bed along the postcapillary and collecting venules. The extravascular leakage of glycosylated albumin, probably due to its electrical or conformational change, may represent the initial event in the development of diabetic microangiopathy.

Animals↗
PubMed1987

Mechanism of isoproterenol-induced angina pectoris in patients with obstructive hypertrophic cardiomyopathy and normal coronary arteries.

In 14 patients with obstructive hypertrophic cardiomyopathy and angiographically normal coronary arteries, 8 with angina (group B) and 6 without (group A), the effects of intravenous isoproterenol, 2 to 4 micrograms/min, followed by intravenous propranolol, 0.2 mg/kg, were studied. An intraventricular systolic gradient less than 50 mm Hg, high-quality echocardiograms and cineangiograms and high-fidelity pressure tracings were selection criteria. Hemodynamic and metabolic variables were assessed during basal conditions, after 5 minutes of isoproterenol infusion or at angina and ST-segment depression, and 5 and 10 minutes after intravenous propranolol infusion. Isoproterenol increased the intraventricular systolic gradient more significantly in group B than in group A (102.4 +/- 8.3 vs 52.2 +/- 8.2, p less than 0.0001). Group B also had higher left ventricular end-diastolic pressure (32.5 +/- 3.9 vs 20.2 +/- 5.7), lower mean arterial pressure (69.7 +/- 3.5 vs 84.7 +/- 4.8) and a smaller increase in coronary sinus flow (176.1 +/- 9.2 vs 261.5 +/- 33.9, all p less than 0.0001), concomitant with lactate release and ST-segment depression. Propranolol promptly reversed hemodynamic and metabolic changes caused by isoproterenol, except for a further coronary sinus flow increase (from 176.1 +/- 9.2 to 219 +/- 14.2 ml/min, p less than 0.001), and heart rate decrease below basal values (57.8 +/- 7.5 vs 79.9 +/- 9.8 beats/min, p less than 0.001) in group B.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1987

Effect of oral levodopa and carbidopa on coronary spasm in variant angina pectoris.

The effect of oral administration of 500 mg of levodopa with 50 mg of carbidopa, a peripheral dopadecarboxylase inhibitor, on coronary vasomotion during vasoconstrictor stimuli was examined in 15 patients with variant angina presenting with hyperventilation-induced myocardial ischemia. Patients were studied during 3 noninvasive sessions and 1 angiographic session. In all sessions the basic protocol consisted of provocation of coronary spasm by hyperventilation before and 2 hours after levodopa and carbidopa administration. During angiography, great cardiac vein blood flow, right atrial and aortic pressures were measured, and coronary angiograms were recorded at baseline and 1 to 4 minutes after each hyperventilation. Samples for dopamine plasma levels were drawn before and throughout the studies. In 3 selected patients, levodopa and carbidopa were associated with 30 mg of domperidone, an antagonist of dopamine peripheral receptors. Levodopa and carbidopa consistently prevented the occurrence of ischemia after hyperventilation in 6 of the 15 patients. This was due to inhibition of local coronary spasm in 2 patients and reduced coronary constriction in 4. Ischemia due to hyperventilation was still prevented despite addition of domperidone with levodopa and carbidopa. Plasma dopamine levels were 23 +/- 15 before and 739 +/- 284 pg/ml 2 hours after administration of levodopa and carbidopa. These findings are consistent with either a decreased central dopaminergic activity and associated disregulation of vasomotor tone, or a peripheral vasodilatory effect of increasing dopamine.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1987

Malignant mesothelioma in non-asbestos textile workers in Florence.

By means of a review of histological diagnosis in the Pathology Department of the University of Florence, suspected cases of malignant mesothelioma, diagnosed in the period 1979-1984, were identified. Study of histological specimens permitted the selection of 13 cases of malignant mesothelioma resident in the Province of Florence. To these cases, referents were matched for age, sex, and year of hospital admission, with residence weighted for the general population of the Province. Both cases and referents (or their next of kin) completed an occupational questionnaire detailing possible occupational exposures. Out of the 13 cases of mesothelioma, 6 were textile workers and 5 of these were "rag-sorters". There were only 5 textile workers among the 52 controls. No asbestos cloth production plants have been in operation in the area from which the cases and referents are derived. Possible sources of exposure to asbestos in the textile industry of this area are discussed.

Aged↗