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G Verde

Publications and source records attributed to G Verde.

At least 19 recordsLinked to original sources
PubMed2006

Neutron and proton transverse emission ratio measurements and the density dependence of the asymmetry term of the nuclear equation of state.

Recent measurements of preequilibrium neutron and proton transverse emission from (112,124)Sn+(112,124)Sn reactions at 50 MeV/A have been completed at the National Superconducting Cyclotron Laboratory. Free nucleon transverse emission ratios are compared to those of A=3 mirror nuclei. Comparisons are made to Boltzmann-Uehling-Uhlenbeck (BUU) transport calculations and conclusions concerning the density dependence of the asymmetry term of the nuclear equation of state at subnuclear densities are made. Comparison to BUU model predictions indicate a density dependence of the asymmetry energy that is closer to a form in which the asymmetry energy increases as the square root of the density for the density region studied. A coalescent-invariant analysis is introduced as a means of reducing suggested difficulties with cluster emission in total nucleon emission.

Journal Article↗
PubMed2004

Isospin diffusion and the nuclear symmetry energy in heavy ion reactions.

Using symmetric 112Sn+112Sn, 124Sn+124Sn collisions as references, we probe isospin diffusion in peripheral asymmetric 112Sn+124Sn, 124Sn+112Sn systems at an incident energy of E/A=50 MeV. Isoscaling analyses imply that the quasiprojectile and quasitarget in these collisions do not achieve isospin equilibrium, permitting an assessment of isospin transport rates. We find that comparisons between isospin sensitive experimental and theoretical observables, using suitably chosen scaled ratios, permit investigation of the density dependence of the asymmetry term of the nuclear equation of state.

Journal Article↗
PubMed2001

Isotopic scaling in nuclear reactions.

A three parameter scaling relationship between isotopic distributions for elements with Z< or =8 has been observed. This allows a simple description of the dependence of such distributions on the overall isospin of the system. This scaling law (termed isoscaling) applies for a variety of reaction mechanisms that are dominated by phase space, including evaporation, multifragmentation, and deeply inelastic scattering. The origins of this scaling behavior for the various reaction mechanisms are explained. For multifragmentation processes, the systematics is influenced by the density dependence of the asymmetry term of the equation of state.

Journal Article↗
PubMed2001

In vitro susceptibility of 137 Candida sp. isolates from HIV positive patients to several antifungal drugs.

Oropharyngeal candidiasis caused by various species of Candida is one of the most common infections in HIV seropositive or AIDS patients. Drug resistance among these yeasts is an increasing problem. We studied the frequency of resistance profile to fluconazole, itraconazole, ketoconazole, amphotericin B and terbinafine of 137 isolates of Candida sp. From HIV positive or AIDS patients with oropharyngeal candidiasis at Instituto de Inmunología, U.C.V. and the Hospital "Jose Ignacio Baldó", Caracas Venezuela, using the well diffusion susceptibility test (Magaldi et al.). We found that nearly 10% of C. albicans isolates were primarily fluconazole resistant, 45% of C. albicans isolates from patients with previous treatment were resistant to fluconazole, of which 93% showed cross-resistance to itraconazole, and even about 30% of C. tropicalis (n = 13) were resistant to fluconazole and/or itraconazole. To this respect, several recent reports have been described antifungal cross-resistance among azoles. Therefore, we consider that C. tropicalis should be added to the growing list of yeast in which antifungal drug resistance is common. This report could be useful for therapeutic aspect in AIDS patients with oral candidiasis.

AIDS-Related Opportunistic Infections↗
PubMed2001

"In vitro" antifungal activity of protease inhibitors.

In the last five years, as HAART has become standard therapy in HIV seropositive or AIDS patients, changes have been noted in the numbers and types of opportunistic fungal infections in these cohorts of patients. Particularly, oropharyngeal candidiasis have become rare in HIV infected patients since the introduction of new anti-HIV drugs of the protease inhibitors type. At the Immunology Institute of the Universidad Central de Venezuela the most frequent protease inhibitors (PIs) used for the treatment of these patients have been: Nelfinavir (Viracept, Roche), Indinavir (Crixivan Merck), Ritonavir (Norvir, Abbott), Saquinavir (Fortovase, Roche). Recently, we observed that recurrent candidiasis was less frequent and no Candida could be isolated in our patients. A direct relation to the PIs was suspected. In order to assess the "in vitro" antifungal activity of the afore mentioned protease inhibitors on Candida sp., we used both the well diffusion test and the NCCLS broth microdilution test to assay 100 Candida sp. isolates from HIV seropositive or AIDS patients with syntomatic oropharyngeal Candida infection. In general, the data obtained with the well diffusion test were in agreement with those obtained by the broth microdilution test. All 100 isolates were susceptible to Saquinavir and 32 were susceptible to Indinavir using the NCCLS microdilution test, while 97 were susceptible to Saquinavir and 52 to Indinavir by the well diffusion test. From 17 C. albicans resistant to fluconazole, all were susceptible to Saquinavir by the NCCLS micromethod and 16 by the well diffusion test. Our results showed anticandidal activity "in vitro" of PIs, mainly Saquinavir.

AIDS-Related Opportunistic Infections↗
PubMed2000

Isospin fractionation in nuclear multifragmentation

Isotopic distributions for light particles and intermediate mass fragments have been measured for 112Sn+112Sn, 112Sn+124Sn, 124Sn+112Sn, and 124Sn+124Sn collisions at E/A = 50 MeV. Isotope, isotone, and isobar yield ratios are utilized to estimate the isotopic composition of the gas phase at freeze-out. Analyses within the equilibrium limit imply that the gas phase is enriched in neutrons relative to the liquid phase represented by bound nuclei. These observations suggest that neutron diffusion is commensurate with or more rapid than fragment production.

Journal Article↗
PubMed1997

Using views for retrieving data from extremely heterogeneous databanks.

Information in molecular biology or biology in general is contained in a multitude of different databanks each specializing in a certain area. This specialization is useful since it improves the maintainability of the data and the flexibility of the overall structure which until now manages to exist without almost any standards. However, information gathering from these extremely heterogeneous sources is difficult since the desired data may be scattered over many databanks. This paper presents the concept of views implemented in the retrieval system SRS that uses links between databanks and a sophisticated parsing engine for information extraction to provide a flexible way of searching and obtaining data across databank boundaries. The implementation provides homogeneous access to all databanks using two types of views: the list-view which displays selected data-fields in their original format and the table-view available for HTML and plain ASCII text which tries to represent the data in a format independent from that of the source databank.

Amino Acid Sequence↗
PubMed1995

Percutaneous ethanol injection (PEI): what is its role in the treatment of benign thyroid nodules?

Ultrasound-guided percutaneous ethanol injection (PEI) was first proposed by Livraghi in 1990 as a possible therapy for autonomously functioning thyroid nodules (AFTN). The procedure is performed on out-patients; is rapid; there is no need of anesthesia, nor of bed rest or patient observation after treatment. Under direct sonographic control a limited amount of 95% sterile ethanol (1-5 ml) is slowly injected into the nodule. In predominantly cystic nodules complete fluid removal is preliminarily performed, and thereafter ethanol is injected on the basis of the aspirated fluid volume without removing the needle. PEI-induced thyroid damage is characterized by coagulative necrosis and haemorrhagic infarction due to vascular thrombosis, and is well defined from the surrounding thyroid parenchyma. Several papers have confirmed the effectiveness of PEI. Normalization of serum TSH and thyroid hormones, marked decrease of nodule volume, and effacement of the previously hyperfunctioning area at thyroid scintiscan are reported in 64-85% of toxic AFTN. Nontoxic AFTN are successfully treated in 80-100% of the cases. PEI significantly superior to aspiration alone in inducing volume reduction of benign cystic thyroid nodules, and the recurrence rate is only 2.5-5%. Complications requiring hospitalization were not reported, but the importance of experienced operators must be stressed to avoid transient dysphonia due to recurrent laryngeal nerve damage. Prior to PEI malignancy must be ruled out by fine needle aspiration in all patients. Radioiodine and surgery remain the treatments of choice of large toxic thyroid nodules, but PEI can be effectively used in selected cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Ethanol↗
PubMed1994

Ultrasound guided percutaneous ethanol injection in the treatment of cystic thyroid nodules.

OBJECTIVE: The management of cystic lesions in the thyroid remains controversial. We examined the efficacy and safety of ultrasound guided percutaneous ethanol injection for the treatment of benign cystic thyroid nodules in euthyroid patients. STUDY DESIGN: (A) Preliminary randomized trial: 20 patients with predominantly cystic thyroid nodules were randomized in two groups and followed up for 1 month. Group 1 underwent fine needle aspiration of the fluid component of the nodules; Group 2 underwent percutaneous ethanol injection at the end of fine needle aspiration of the cyst fluid. (B) Prospective study: 32 patients with the same clinical characteristics (Group 3) were treated by fine needle aspiration and percutaneous ethanol injection, and followed up for 12 months. METHODS: Groups 1 and 2: clinical evaluation, thyroid ultrasonography, thyroid scintiscan and serum thyroid hormone profile were performed before treatment and one month later. Group 3: clinical evaluation, thyroid ultrasonography and serum thyroid hormone profile were performed in basal conditions and 1, 3, 6, 9, 12 months after treatment. Thyroid scintiscan was performed before treatment and 3-6 months later. RESULTS: (A) Randomized study: one month after treatment, nodule volume decrease in Group 2 was significantly higher than in Group 1 (Group 2: median 14.75 range 6-29.9 ml; Group 1: median 3.65 range 0.2-18.5 ml; P < 0.01). Nodule volume reduction was greater than 50% versus baseline in 8 (80%) patients in Group 2 and in 3 (30%) patients in Group 1 (P < 0.01). (B) Prospective study (Group 3): a significant nodule volume reduction (P < 0.01 vs pretreatment) was observed 1 and 12 months after percutaneous ethanol injection (pretreatment: median 14.5, range 1.5-65.8 ml; 1 month: median 3.5, range 0.4-38.9 ml; 12 months: median 2.5, range 0.4-34.5 ml). Nodule volume reduction greater than 50% was recorded in 24 (80%) patients. Groups 1-3: recurrence of cyst fluid was demonstrated by ultrasonography in 8 patients of Group 1, in 3 patients of Group 2 and in 1 patient of Group 3. No relevant adverse effects or significant biochemical changes were observed. CONCLUSIONS: Ultrasound guided percutaneous ethanol injection of cystic thyroid nodules is a safe, low-cost and effective therapeutic procedure in patients with benign thyroid cystic nodules. Indeed, nodule volume reduction was significantly greater and more frequent in patients treated by percutaneous ethanol injection than in those patients who underwent fluid aspiration alone. These results were confirmed in a long-term prospective trial and only one fluid recurrence was observed during 12 months of follow-up.

Adolescent↗
PubMed1992

Distal nephron function in Bartter's syndrome: abnormal conductance to chloride in the cortical collecting tubule?

Five patients with the clinical patterns of Bartter's syndrome underwent a series of clearance studies in order to characterize the underlying tubule defect. Free water generation during maximal water diuresis (CH2O), expressed as percentage of the distal delivery (CH2O + CCl), was lower in the patients (72.5 +/- 3.2%) than in controls (84.4 +/- 5.5, p < 0.0001). During maximal water diuresis and furosemide administration (40 mg i.v. as bolus), NaCl reabsorption along the diluting nephron segments could be separated into 2 components, that occurring in the loop of Henle (DRNaHL) and that occurring in tubule segments beyond the macula densa (DRNaDT): DRNaHL was normal, while DRNaDT was reduced (3.1 +/- 0.8 vs. 6.2 +/- 2.5 ml/min in controls, p < 0.015). Thus, according to this furosemide protocol, our patients had normal solute reabsorption in the loop of Henle but reduced NaCl reabsorption in tubule segments beyond the macula densa. During 0.9% saline infusion (2 liters in 2 h, after stimulation of distal Na reabsorption with fludrocortisone) fractional excretion (FE) of K showed a linear rise with the increase of FECl-FEK, however, was much higher in the patients than in controls for every FECl level. In contrast, the infusion of Na2SO4, after fludrocortisone administration, induced similar FEK increases in patients and in controls. Thus, in these patients Na reabsorption in the distal nephron (possibly the cortical collecting tubule) was associated with the generation of a higher than normal electric potential gradient in the presence of Cl but not of another poorly reabsorbable anion, such as SO4(2-). These observations indicate that, in our patients, Henle's loop function is normal, while the collecting tubule function is abnormal. We suggest that NaCl wasting and enhanced tubular secretion of H+ and K in our patients might result from an abnormally low conductance to Cl in distal nephron site(s) where Na reabsorption is electrogenic, possibly the cortical collecting tubule. A larger than normal transtubular electric gradient would be generated by Na reabsorption, causing: (1) a direct stimulation of tubular secretion of K and H+ (leading to hypokalemia and alkalosis) and (2) inhibition of the reabsorption of Na ('trapped' into the tubular lumen by electric forces), with consequent extracellular volume contraction, hyperreninemia and hyperaldosteronism.

Adolescent↗
PubMed1991

Doxorubicin for acromegaly: a case report.

We report the case of an acromegalic woman, aged 35 years, with a huge GH-secreting tumor, repeatedly treated with neurosurgery and radiotherapy, not responsive to bromocriptine (Br) and octreotide (SMS), whose clinical picture evolved to coma due to endocranic hypertension. Since remnant size was too large to be further treated by surgery, chemotherapy with doxorubicin (DOX) (100 mg i.v. every three weeks up to 0.5 mg/m2 over 7 months) was started. Treatment was followed by a rapid improvement of clinical picture with resumption out of coma, progressive decline of GH levels (from 800 ng/ml to 15 ng/ml) and a slight shrinkage of tumor. No side effects were observed during DOX administration. We suggest that in those few acromegalic patients resistant both to SMS and Br, and with poor prognosis, DOX may be effectively used.

Acromegaly↗