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Biomedical subjects

V Carbone

Publications and source records attributed to V Carbone.

At least 19 recordsLinked to original sources
PubMed2006

Reusing ethyl acetate and aqueous exhausted fractions of dry olive mill residue by saprobe fungi.

Some saprobe fungi (Phlebia radiata, Trametes versicolor, Coriolopsis rigida, Pycnoporus cinnabarinus, Fomes sclerodermus or Pleurotus pulmonarius) were able to bioconvert the ethyl acetate fraction (DEAF) and the corresponding aqueous exhausted fraction (EAF) of dry olive mill residue (DOR), reducing their phytotoxicity on Lepidium sativum seeds. Large amount of hydroxytyrosol together with other eight monomeric phenols were found in the native DEAF fraction, which represents a good source of antioxidants. P. radiata, T. versicolor and F. sclerodermus caused an effective phytotoxicity reduction of EAF in the concentration range of 25-3 gl(-1). In particular, in the range between 12.5 and 3 gl(-1), the EAF samples inoculated with P. radiata and F. sclerodermus surprisingly stimulated the germinability of L. sativum, suggesting their use as a potential biofertilizer. This is the first report which showed the bioconversion of the above fractions in shorter time with respect to the previous findings concerning DOR. The possible implications of laccase in the decrease of DEAF and EAF phytotoxicity was also discussed.

Acetates↗
PubMed2006

Clustering of polarity reversals of the geomagnetic field.

Often in nature the temporal distribution of inhomogeneous stochastic point processes can be modeled as a realization of renewal Poisson processes with a variable rate. Here we investigate one of the classical examples, namely, the temporal distribution of polarity reversals of the geomagnetic field. In spite of the commonly used underlying hypothesis, we show that this process strongly departs from a Poisson statistics, the origin of this failure stemming from the presence of temporal clustering. We find that a Lévy statistics is able to reproduce paleomagnetic data, thus suggesting the presence of long-range correlations in the underlying dynamo process.

Journal Article↗
PubMed2006

Periodic and aperiodic traveling pulses in population dynamics: an example from the occurrence of epidemic infections.

The dynamics of the occurrence of the dengue hemorrhagic fever in the 72 provinces of Thailand is investigated by performing a proper orthogonal decomposition (POD) on spatiotemporal data. Using this technique, we are able to identify and select the contribution of different modes, selected according to the energy content, to the evolution of the epidemic during 14 years. We found that the phenomenon is characterized by periodic cycles of yearly occurrence characterized by spatial scales of about 420 km. Superimposed on this basic mode, POD analysis is able to reveal the presence of high-energetic aperiodic traveling pulses of the epidemic, which extend spatially for about 510 km from Bangkok.

Communicable Diseases↗
PubMed2005

Proper orthogonal decomposition of solar photospheric motions.

The spatiotemporal dynamics of the solar photosphere is studied by performing a proper orthogonal decomposition (POD) of line of sight velocity fields computed from high resolution data coming from the MDI/SOHO instrument. Using this technique, we are able to identify and characterize the different dynamical regimes acting in the system. Low-frequency oscillations, with frequencies in the range 20-130 microHz, dominate the most energetic POD modes (excluding solar rotation), and are characterized by spatial patterns with typical scales of about 3 Mm. Patterns with larger typical scales of approximately 10 Mm, are associated to p-modes oscillations at frequencies of about 3000 microHz.

Journal Article↗
PubMed2001

Aspartyl protease inhibitor pepstatin binds to the presenilins of Alzheimer's disease.

Mutations in the presenilin genes PS1 and PS2 cause early-onset Alzheimer's disease by altering gamma-secretase cleavage of the amyloid precursor protein, the last step in the generation of Abeta peptide. Ablation of presenilin (PS) genes, or mutation of two critical aspartates, abolishes gamma-secretase cleavage, suggesting that PS may be the gamma-secretases. Independently, inhibition experiments indicate that gamma-secretase is an aspartyl protease. To characterize the putative gamma-secretase activity associated with presenilins, lysates from human neuroblastoma SH-SY5Y and human brain homogenates were incubated with biotin derivatives of pepstatin, followed by immunoprecipitation of PS and associated proteins, and biotin detection by Western blotting. Precipitation with PS1 antibodies, directed to either N-terminal or loop regions, yielded the same 43 kDa band, of apparent molecular mass consistent with that of full-length PS1, although it may represent an aspartyl protease complexed with PS1. Incubation of cell lysates with pepstatin-biotin, followed by streptavidin precipitation and PS1 Western blotting, revealed PS1 fragments and full-length protein, indicating that pepstatin-biotin bound to both cleaved and uncleaved PS1. Binding could be competed by gamma-secretase inhibitor L-685,458 and could not be achieved with a PS1 mutant lacking the two transmembrane aspartates. Pepstatin-biotin was also shown to bind to PS2. PS1 was specifically absorbed to pepstatin-agarose, with an optimal pH of 6. Binding of pepstatin-biotin to PS1 from lymphocytes of a heterozygous carrier of pathologic exon 9 deletion was markedly decreased as compared to control lymphocytes, suggesting that this PS1 mutation altered the pepstatin binding site.

Alzheimer Disease↗
PubMed2001

Transport processes in reversed-field-pinch plasmas: inconsistency with the self-organized-criticality paradigm.

A statistical analysis of the anomalous particle flux in the edge region of the RFX experiment has revealed that laminar times between bursts, which account for more than 50% of the losses, have a power law distribution and that flux fluctuations are not self-similar. These properties are found in contrast with a wide class of self-organized-criticality models so that it is concluded that there is no experimental evidence of avalanchelike process occurrence in the plasma of RFX.

Journal Article↗
PubMed2001

Homoclinic gluing bifurcations during the light induced reorientation in nematic-liquid-crystal films.

An s-polarized laser beam that impinges at small incidence angle on a homeotropically aligned nematic liquid crystal produces very interesting nonlinear phenomena. In this paper, we show that, due to the symmetry of the system, a cascade of successive homoclinic gluing bifurcations is responsible for the transition towards a stochastic regime in the experiment. We compare the experimental results with a model describing a sequence of gluing bifurcations.

Journal Article↗
PubMed2001

Search of self-organized criticality processes in magnetically confined plasmas: hints from the reversed field pinch configuration.

In order to test the self-organized criticality (SOC) paradigm in transport processes, a novel technique has been applied for the first time to plasmas confined in reversed field pinch configuration. This technique consists of an analysis of the probability distribution function of the times between bursts in density fluctuations measured by microwave reflectometry and electrostatic probes. The same analysis has also been applied to intermittent events sorted out from the Gaussian background. In both cases, the experimental results disagree with the predictions for a SOC system.

Journal Article↗
PubMed2001

Studies on the constituents of Cyclanthera pedata fruits: isolation and structure elucidation of new flavonoid glycosides and their antioxidant activity.

The isolation of six flavon glycosides (1-6), among them four new natural compounds (1-4), from the CHCl(3)/MeOH extract of the fruits of Cyclanthera pedata is reported. All of the structures were elucidated by spectroscopic methods, including the concerted application of one-dimensional ((1)H, (1)H TOCSY, (13)C, and (13)C DEPT-NMR) and two-dimensional NMR techniques (DQF-COSY, HSQC, and HMBC). For all of the isolated compounds the antioxidant activity was determined by measuring the free radical scavenging activity, using the Trolox equivalent antioxidant capacity (TEAC) method, and the coupled oxidation of beta-carotene and linoleic acid.

Carbohydrate Conformation↗
PubMed2001

Scaling laws and forecasting in athletic world records.

In this study, we analysed running world records and found that the mean speed of the race, mu, as a function of the record time, tau, can be described asymptotically by two well-defined scaling laws of the form mu approximately tau(-beta). There is a break in the scaling laws (approximately 1000 m) between the shorter and the longer races at a characteristic time of around 150-170 s, after which a new scaling regime emerges. This is the first occasion that this characteristic time has been clearly found in physical terms; we interpreted it as the transition time between the anaerobic and the aerobic energy expenditure of athletes. This phenomenon is independent of the athletes' sex and is also found in swimming races with similar values of the characteristic time. We also investigated the forecasting of world records using historical data. Using an approach based on the identification of non-Poissonian events for a sequence of temporal point processes, we found that the sequence of improvements in all athletic records from 1900 to the present day cannot be considered as a sequence of completely random events.

Anaerobic Threshold↗
PubMed2001

Identification of Hb Villejuif [beta123(H1)Thr-->Ile] in Southern Italy.

Hb Villejuif [beta123(H1)Thr-->Ile] is a silent and asymptomatic variant described in 1989 in an 87-year-old woman of French origin suffering from coincidental polycythemia vera. This paper reports the second observation of Hb Villejuif in three related subjects from Montesarchio, Southern Italy. All routine techniques for hemoglobin analysis yielded normal results with the exception of a slight increase in the Hb A2 value. The occurrence of a variant beta-globin was rapidly assessed by liquid chromatography mass spectrometric analysis and the abnormal chain purified by high performance liquid chromatography. The amino acid replacement Thr-->Ile at beta123 was determined by tandem electrospray mass spectrometric analysis of the tryptic digest of the variant beta chain. The corresponding DNA mutation was established as C-->T at the second position of codon 123 (ACC-->ATC) by polymerase chain reaction amplification techniques.

Adult↗
PubMed2000

Scavenging of peroxynitrite by oxyhemoglobin and identification of modified globin residues.

Peroxynitrite is a strong oxidant involved in cell injury. In tissues, most of peroxynitrite reacts preferentially with CO(2) or hemoproteins, and these reactions affect its fate and toxicity. CO(2) promotes tyrosine nitration but reduces the lifetime of peroxynitrite, preventing, at least in part, membrane crossing. The role of hemoproteins is not easily predictable, because the heme intercepts peroxynitrite, but its oxidation to ferryl species and tyrosyl radical(s) may catalyze tyrosine nitration. The modifications induced by peroxynitrite/CO(2) on oxyhemoglobin were determined by mass spectrometry, and we found that alphaTyr42, betaTyr130, and, to a lesser extent, alphaTyr24 were nitrated. The suggested nitration mechanism is tyrosyl radical formation by long-range electron transfer to ferrylhemoglobin followed by a reaction with (*)NO(2). Dityrosine (alpha24-alpha42) and disulfides (beta93-beta93 and alpha104-alpha104) were also detected, but these cross-linkings were largely due to modifications occurring under the denaturing conditions employed for mass spectrometry. Moreover, immunoelectrophoretic techniques showed that the 3-nitrotyrosine content of oxyhemoglobin sharply increased only in molar excess of peroxynitrite, thus suggesting that this hemoprotein is not a catalyst of nitration. The noncatalytic role may be due to the formation of the nitrating species (*)NO(2) mainly in molar excess of peroxynitrite. In agreement with this hypothesis, oxyhemoglobin strongly inhibited tyrosine nitration of a target dipeptide (Ala-Tyr) and of membrane proteins from ghosts resealed with oxyhemoglobin. Erythrocytes were poor inhibitors of Ala-Tyr nitration on account of the membrane barrier. However, at the physiologic hematocrit, Ala-Tyr nitration was reduced by 65%. This "sink" function was facilitated by the huge amount of band 3 anion exchanger on the cell membrane. We conclude that in blood oxyhemoglobin is a peroxynitrite scavenger of physiologic relevance.

Ascorbic Acid↗
PubMed2000

Treatment outcome among child psychiatric outpatients in a community mental health center.

The study evaluated the effectiveness of mental health center treatments for children aged 5-12 years. The Child Behavior Checklist (CBCL) was administered before and after treatment to the parents of the treatment group (N = 71). The results were analyzed and compared to the results of the pretest and posttest CBCL administered to the parents of a matched group of comparison subjects (N = 33). The results showed that the treatment subjects significantly improved on both the externalizing and internalizing scales of the CBCL. The controls showed no significant change between pretest and posttest scores. As a result, it appears that clinic treatments can help clients with measurable problems decrease problematic behaviors. More data is needed to determine whether clinic treatments such as the ones described in this study can substantially help the most seriously disturbed school-age children.

Ambulatory Care↗
PubMed2000

Nonlinear dynamics optically induced in nematic liquid crystals

We report the analysis of the dynamical regimes induced in a homeotropically aligned nematic liquid-crystal layer when an s-polarized laser beam impinges at a small incident angle. These regimes are studied by analyzing the time series of the variation of the polarization state of a light probe beam, recorded at different light intensities. A detailed description of the dynamical regimes, based on the analysis of the wavelet transforms performed on the observed time series, is presented. We recognize a first Hopf bifurcation followed by a gluing bifurcation, and a further transition toward an irregular regime. Similarities between our experimental results and a scenario of transition to chaos via a sequence of gluing bifurcations have been discussed.

Journal Article↗
PubMed2000

Intermittency and turbulence in a magnetically confined fusion plasma

We investigate the intermittency of magnetic turbulence as measured in reversed field pinch plasmas. We show that the probability distribution functions of magnetic field differences are not scale invariant; that is, the wings of these functions are more important at the smallest scales, a classical signature of intermittency. We show that scaling laws appear also in a region very close to the external wall of the confinement device, and we present evidences that the observed intermittency increases moving towards the wall.

Journal Article↗
PubMed2000

Low-dose monitored mitotane treatment achieves the therapeutic range with manageable side effects in patients with adrenocortical cancer.

Eight patients with adrenocortical cancer were treated with low doses of mitotane (2-3 g daily) while monitoring drug plasma levels. When the mitotane concentrations reached the therapeutic range (defined as mitotane plasma levels between 14-20 microg/mL), a dose reduction was performed to avoid toxicity. Thereafter, the mitotane dose was tailored according to plasma levels. A progressive increase in plasma mitotane concentrations was observed during treatment, and a highly significant linear correlation was found between plasma drug levels and the total mitotane dose. The therapeutic threshold was reached in all patients after 3-5 months and a total mitotane dose of 283-387 g/days (median, 363). The duration of treatment was 8-40 months (median, 9). Toxicity was manageable in all but one patient, who discontinued treatment. It is therefore possible to design a standard low dose schedule, e.g. 3 g/daily for about 3-4 months with following dose adjustments guided by the monitoring of plasma mitotane levels. This approach is able to provide therapeutic mitotane concentrations and limit the unwanted effects. The present data provide a rationale to change the approach to mitotane treatment in patients with adrenocortical carcinoma from high dose to low dose regimens.

Adrenal Cortex Neoplasms↗