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Biomedical subjects

L Basile

Publications and source records attributed to L Basile.

17 recordsLinked to original sources
PubMed2004

Breakup of quasiparticles in thin-film quantum wells.

Quantum well states in thin films are commonly described in terms of a quasiparticle confined in a quantum box, but this single-particle picture can fail dramatically near a substrate band edge, as shown by this angle-resolved photoemission study. Atomically uniform Ag films are prepared on Ge(111) to facilitate accurate line shape and dispersion relation measurements. A quantum well peak is observed to split into two peaks near the Ge valence band edge. The unusual line shapes are shown to be due to many-body interactions and are quantitatively explained by a Green's function calculation.

Journal Article↗
PubMed2004

Quantum beating patterns observed in the energetics of Pb film nanostructures.

We have studied the nanoscale structural evolution of Pb films grown at 110 K on a Si(111) substrate as they are annealed to increasingly higher temperatures. Surface x-ray diffraction from a synchrotron source is used to observe the morphology evolve from an initial smooth film through various metastable states before reaching a state of local equilibrium, at which point the coverage of different height Pb structures is analyzed and related to the thickness-dependent surface energy. Rich patterns are seen in the resulting energy landscape similar to the beating patterns heard from the interference of two musical notes of similar pitch. The explanation is, however, very simple, as demonstrated by a model calculation based on the confinement of free electrons to a quantum well.

Journal Article↗
PubMed2003

Quantum oscillations in the layer structure of thin metal films.

Understanding the underlying physical principles that determine the internal structure of objects at the atomic scale is critical for the advancement of nanoscale science. We have performed synchrotron x-ray diffraction studies to determine the structural properties of smooth Pb films with varying thicknesses of 6 to 18 monolayers deposited on a Si(111) substrate at 110 K. We observe quasibilayer variations in the atomic interlayer spacings of the films consistent with charge density oscillations due to quantum confinement of conduction electrons and surface-interface interference effects. Quantum oscillations in atomic step height are also deduced.

Journal Article↗
PubMed2003

Alternating layer and island growth of Pb on Si by spontaneous quantum phase separation.

Real-time in situ x-ray studies of continuous Pb deposition on Si(111)-(7x7) at 180 K reveal an unusual growth behavior. A wetting layer forms first to cover the entire surface. Then islands of a fairly uniform height of about five monolayers form on top of the wetting layer and grow to fill the surface. The growth then switches to a layer-by-layer mode upon further deposition. This behavior of alternating layer and island growth can be attributed to spontaneous quantum phase separation based on a first-principles calculation of the system energy.

Journal Article↗
PubMed2002

The protective role of epithelium-derived nitric oxide in isolated bovine trachea.

Airway epithelial cells from bovine airways can release relaxant factors such as nitric oxide (NO) and prostaglandin E(2) and the removal of airway epithelium results in an increased responsiveness of smooth muscle to spasmogen stimuli. In this study, we assessed whether or not epithelial NO modulates the contractile response of bovine trachea in vitro.Cumulative concentration-response curves to acetylcholine (ACh), histamine (Hist) and 5-hydroxytryptamine (5-HT) were obtained in both intact and epithelium denuded tracheal strips in the presence of indomethacin (10 microM).In intact, but not in epithelium denuded strips, preincubation with the NO synthase inhibitor L-N((G))-Nitro-arginine methyl ester (L-NAME), but not with D-NAME, shifted to the left the concentration-response curve to ACh (pD(2) values in the absence and in the presence of L-NAME were 3.47+/-0.1 and 4.60+/-0.1, respectively; P<0.05) and to Hist (pD(2) in the absence and in the presence of L-NAME: 3.89+/-0.1 and 4.54+/-0.1, respectively; P<0.05). This effect was reversed by L-arginine (1mM), but not by D-arginine. The contractile response to 5-HT was not affected by L-NAME in either intact or epithelium denuded strips. These data suggest that NO is an epithelial relaxant factor modulating airway cholinergic and histaminergic contraction of bovine trachea and that the activation of the epithelial NO synthase is a mediator-specific process.

Acetylcholine↗
PubMed2000

[Magnetic resonance cholangiopancreatography: comparative study with direct cholangiography].

Magnetic Resonance Cholangiopancreatography (MRCP) is an emergent non invasive diagnostic technique for the study of pancreaticobiliary system. Following the contraindications of traditional Magnetic Resonance, the MRCP is safe for the patient. Images can be obtained without administration of any contrast and not using Rx. The objective of this study is to evaluate the sensitivity and the specificity of MRCP respect direct cholangiography ([endoscopic retrograde cholangiography (ERCP) and percutaneous transhepatic cholangiography (PTC)]. Forty one patients older than 60 years old were included, 19 male and 22 female, 73.5 median age. All of them have clinical diagnosis of obstructive jaundice. The patients were tested with MRCP first, and blinded of this results a direct cholangiography (DC) were done (ERCP 34 and PTC 8), less than 48 hs after MRCP. For the present study, the sensitivity was 100% and specificity was 90% of MRCP in the diagnosis of normal biliary tract. For the dilated biliary tract the sensitivity was 93% and the specificity was 92%. In bile duct obstruction the sensitivity was 88% without false positive. MRCP diagnosed the presence of choledocholithiasis with a sensitivity of 74% and specificity of 95%, lower than reported in other studies. 73% of our patients required some kind of therapeutic intervention. MRCP has high sensibility and specificity in the initial evaluation of patients with clinical obstructive jaundice and could replace the DC when is used for diagnostic purpose.

Aged↗
PubMed1998

Subtemporal suboccipital transpetrosal transsigmoidal approach to aneurysm of the basilar artery fenestration.

The aneurysm arising from the lower third of a basilar artery fenestration is a rare event. The traditional suboccipital or subtentorial transtentorial or transoral approach to this vascular malformation can be problematic. We report the case of a 52-year-old woman who suffered a Grade 4 subarachnoid hemorrhage from an aneurysm located at a fenestration of the proximal third of the basilar artery. This aneurysm was successfully clipped through a left subtemporal suboccipital translabyrinthine transsigmoidal approach. In the aneurysms of the proximal third of the basilar artery the transpetrosal approach with its variants (translabyrinthine and transsigmoidal) related to patient's clinical condition can be useful with undoubted advantages.

Basilar Artery↗
PubMed1998

Management of "critical" aneurysms of the anterior circulation: technical suggestions.

This paper first goal is to establish what "critical" aneurysm means. We decided to consider as "critical" aneurysms those whose correct clipping-treatment would be particularly difficult; this particular difficulty could concern the malformation intrinsic characteristics as well as extrinsic factors (the patient's clinical conditions as well as insufficient organizational or technical facilities). We thus reviewed 277 aneurysms operated in the Neurosurgical Department of Varese from 1988 to 1994. We excluded 18 vertebro-basilar system aneurysms; the clinical and surgical charts of the 259 remaining aneurysms were reviewed and informations regarding their last clinical conditions were gathered. In this way it was possible for us to distinguish different categories of critical aneurysms: critical for their anatomical position, morphology, size and for their number; unpredictably critic aneurysms and aneurysms associated with the patient's critical conditions were also considered. After describing our technical solutions and those suggested by the current literature we concluded that what is required to treat these critical aneurysms is not an extraordinary surgical skill, but a good organizational and technical facility at the surgical-team's disposal.

Cerebral Angiography↗
PubMed1994

Idiopathic middle cerebral artery occlusion in children: report on three cases.

Three cases of middle cerebral artery occlusion in children are reported. The origin of M1 was the site of occlusion in two cases, while occlusion 1 cm after the origin of M1 was found in the third. The possible etiological diagnosis was infectious arteritis in the first two cases, cranial trauma in the third. In no case were serious contralateral motor deficits detected in follow-up examinations. Follow-up digital subtraction angiography showed complete regression of arterial lesions in the second case. The authors conclude that middle cerebral artery occlusion may have a benign clinical course in children; surgical revascularization is indicated only in highly selected cases.

Arteritis↗
PubMed1993

Cerebellar hemorrhage in xanthomatous neoplastiform lesion of vermis cerebelli. Case report.

A xanthomatous lesion of vermis cerebelli was removed successfully from the posterior fossa of a 19 years old girl with insulin-dependent diabetes and hypercholesterolemia, admitted for cerebellar hemorrhage. A review of literature shows that this is the first case of xanthomatous lesion presented with cerebellar hemorrhage. The pathogenesis of this lesion is reviewed as it relates to the presentation of this case.

Adult↗
PubMedDate not supplied

Demographic evolution and production structure in Naples according to the information of the latest censuses.

Changes in the industrial structure of Naples, Italy, between 1971 and 1981 are examined using census data. The first part analyzes demographic shifts in the city's population. "In the closing years of that period a decline in population growth was observed and, over its last decade, there was also a change in its structure in that there was an increase in the labour force due to the huge number of young people who entered the labour market."

Age Distribution↗
PubMedDate not supplied

[The effects of bromazepam on contingent negative variation and reaction time in a visuomotor task].

INTRODUCTION: Bromazepam is the second most commonly used benzodiazepine in Brazil. Psychophysiological research on this substance is still in its early stages. AIM: To determine the neurotoxicity of bromazepam by examining reaction times (RT) and contingent negative variations (CNV). SUBJECTS AND METHODS: Using a videogame produced in our laboratory for psychophysiological research purposes (Car Acquisition), 14 healthy volunteers (9 males) aged between 23 and 42 drove a vehicle along a road full of curves (i.e. distractors) while they had to respond to imperative stimuli (i.e. orders to press the button on the joystick) that were preceded by warnings (S1-S2-RM paradigm with distractor). We compared RT, amplitudes and latencies of the CNV at each of the three electrodes on the median line (Fz, Cz and Pz) one hour after random, double-blind and crossed administration of placebo (P), 3 mg of bromazepam (B3) or 6 mg of bromazepam (B6) on different days. STATISTICS: one-way ANOVA and Post Hoc Scheffé. RESULTS: No significant differences were observed in the RT. At Pz, the CNV amplitudes displayed significant differences for P, B3 and B6 (p = 0.006), and also for B3 and B6 (p = 0.018), with B6 > B3 = P. At Fz, a non-significant tendency (p = 0.074) suggested a difference between the latencies, shorter in B6 than in B3 (p = 0.098), both equivalent to placebo. The mean amplitudes ranged between 2.4 and 5.9 microV. CONCLUSIONS: Behavioural and neurophysiological neurotoxicity was insignificant one hour after administration of a single 3 or 6 mg dose of bromazepam in healthy young adults. Low mean amplitudes were compatible with the interference from distractors and did not result in floor effect.

Adult↗