Biomedical subjects

C Balducci

Publications and source records attributed to C Balducci.

27 records · Page 2Linked to original sources

PubMed1998

Characterization of the effects of the partial dopamine agonist terguride on cocaine self-administration in the rat.

Dopamine neurotransmission is an important neuropharmacological component of cocaine self-administration in rodents. Terguride is a prototype drug belonging to a recently characterized class of compounds, dopamine partial agonists, which appear to possess a unique pharmacological profile in altering dopamine neurotransmission, where these drugs act as antagonists in conditions of high dopaminergic tone. The aim of the present study was therefore to test the effects of systemic administration of terguride in rats self-administering cocaine intravenously. The different aspects of cocaine self-administration examined after treatment with terguride were (a) the acute reinforcing properties of cocaine in rats exposed to limited-access self-administration of cocaine, (b) a full cocaine dose-effect function, (c) the reinforcing properties of cocaine as measured by a progressive ratio schedule and (d) the ability of terguride to maintain self-administration by itself. Terguride (0.025-0.4 mg/kg i.p.) significantly and dose-dependently reduced the acute reinforcing properties of cocaine as measured by an increase in responding for a single training dose of cocaine and a reduction of the inter-reinforcement interval. In addition, terguride (0.2-0.4 mg/kg) shifted the entire cocaine dose-effect function to the right, thus showing an antagonism of the reinforcing properties of cocaine independent of response rate. Moreover, in rats trained to self-administer cocaine on a progressive ratio schedule, terguride reduced the maximum fixed ratio ("breaking point") for cocaine reinforcement, also suggesting a decrease in the reinforcing properties of cocaine. Finally, in rats trained to self-administer cocaine terguride did not substitute for cocaine, thus indicating that terguride does not maintain intravenous self-administration by itself.

Animals↗

PubMed1997

Dextromethorphan reduces intravenous cocaine self-administration in the rat.

Dextromethorphan is a widely used antitussive agent with non-competitive antagonistic effects at the excitatory amino acid receptors of the NMDA type. Since excitatory amino acid neurotransmission has been implicated in cocaine dependence, the aim of the present study was to evaluate the effects of acute systemic administration of dextromethorphan in rats trained to self-administer cocaine intravenously. The experiments were designed to evaluate the effects of dextromethorphan on responding for cocaine and cocaine reward magnitude. The hypothesis was that dextromethorphan could attenuate specific aspects of cocaine-seeking behavior thus providing a preclinical rationale for its clinical use. The results reported reveal that acute pretreatment with dextromethorphan (10-50 mg/kg i.p.) significantly reduced cocaine self-administration in rats self-administering the drug intravenously in a simple continuous reinforcement schedule. In addition, acute pretreatment with an effective dose of dextromethorphan (25 mg/kg) decreased cocaine self-administration in rats tested at various doses of cocaine (0.12-0.5 mg/injection). Finally, dextromethorphan (25 mg/kg) also reduced the absolute reward magnitude of cocaine as measured by responding for cocaine in a progressive ratio schedule. These results encourage further experimental and clinical studies to evaluate the potential use of dextromethorphan during various phases of the natural history of cocaine dependence in humans.

Animals↗

PubMed1996

Dopamine partial receptor agonists reduce ethanol intake in the rat.

Dopamine neurotransmission is an important neuropharmacological component of ethanol reinforcement in rodents. A recently characterized class of compounds, dopamine partial receptor agonists, appears to possess a unique pharmacological profile on dopamine neurotransmission. The aim of the present study was to test the effects of systemic administration of terguride and SDZ 208-911 (N-[(8 alpha)-2,6-dimethylergoline-8-yl]-2,2-diethylpropanamide), two prototype dopamine partial receptor agonists, in free-feeding, non-deprived rats trained to drink ethanol (10% w/v) and water in 'free-choice' limited access conditions. Both acute and chronic administration of terguride and SDZ 208-911 significantly reduced ethanol intake while water intake was not significantly affected, thus ruling out possible non-specific effects of these drugs on fluid intake. These results suggest that dopamine partial receptor agonists reduce the reinforcing properties of ethanol in the rat, an effect similar to that previously observed with cocaine. Therefore, the pharmacological profile of dopamine partial receptor agonists and their effects in animal models of dependence provide preclinical support to the hypothesis that these compounds may represent a novel pharmacological strategy for intervention in various forms of drug addiction.

Alcohol Drinking↗

PubMed1996

Inhibition of nitric oxide synthesis reduces intravenous cocaine self-administration in the rat.

The effects of a blockade of nitric oxide synthesis were studied in rats trained to self-administer cocaine intravenously. Pretreatment with Ng-nitro-1-arginine methyl ester (l-NAME; 10-50 mg/kg, intraperitoneally, twice daily for 4 days), significantly and dose-dependently suppressed the maintenance of intravenous cocaine self-administration and the absolute reward magnitude of cocaine. These results suggest that nitric oxide may play a role in cocaine abuse and dependence.

Animals↗

PubMed1994

Trace element reference values in tissues from inhabitants of the European Union. VIII. Thallium in the Italian population.

In order to establish reference values of thallium in tissues of the general population the element was determined in blood (TlB) and urine (TlU) of 123 healthy inhabitants living in the Marche region, Central Italy. The analysis was carried out by inductively coupled plasma-mass spectrometry (ICP-MS; detection limit in our experimental conditions, 0.001 micrograms Tl/I), which was validated by neutron activation analysis (NAA) and laser induced fluorecence (LIF) spectroscopy. The check of pre-analytical factors indicated a low risk of contamination and loss of Tl during sampling, handling and storage before the instrumental analysis (blank of the entire procedure less than the detection limit). Mean values of TlU and TlB were 0.066 micrograms Tl/l and 0.063 micrograms Tl/l, respectively (median in both cases 0.057 microgram Tl/l). No conclusive evidence concerning the distribution followed by our data set, normal or log-normal, were drawn, although Lilliefors test and Kolmogorov's D-test showed a tendency for TlB to follow both the normal and the log-normal while TlU followed a log-normal distribution. Overall correlations between TlU and TlB are rather weak. A significant, but not high, correlation (P < 0.0004, r = 0.44) was observed in females. Age, sex, smoking habits and alcohol consumption did not seem to play any role on TlU and TlB. Tentatively proposed reference intervals are 0.019-0.17 microgram Tl/l (urine) and 0.014-0.19 microgram Tl/l (blood).

Adult↗

PubMed1979

Genes and mRNAs coding for zein polypeptides in Zea mays.

Zein messenger RNAs from maize endosperm were purified by successive oligo(dT)-cellulose chromatography and sucrose gradient centrifugation. Polyacrylamide gel electrophoresis under denaturing conditions revealed the presence of two size classes of zein messenger RNAs of Mr 3.5 x 10(5) and 4.10 x 10(5). The mRNA was shown to synthesize the major zein polypeptides, to have a base composition characteristic of a poly(A)-containing RNA and to be transcribed by reverse transcriptase into complementary DNA. The r0t1/2 of the hybridization curve of cDNA hybridized to an excess of mRNA was shown to be 7 x 10(-2) M . s indicating that about 15 non-cross-hybridizing sequences are present in the zein mRNA preparations. The kinetics of cDNA annealing with an excess of maize DNA from 2 n cells suggest a ten-times reiteration of each mRNA sequence. This result is confirmed from saturation experiments, where in cDNA excess to DNA, the number of zein genes per haploid maize genome was estimated as about 120 copies. Similar experiments carried out on DNA from normal and mutant endosperms (3n cells) indicate the absence of large amplifications or deletions of zein genes in the tissue devoted to zein synthesis.

DNA↗

PubMed1978

Adaptation of the tRNA population of maize endosperm for zein synthesis.

Maize endosperm, 30 days after pollination is actively synthesizing zein, a storage protein containing high amounts of glutamine. leucine and alanine. Endosperm tRNAs have a higher accepting activity than embryo tRNAs for these three amino acids, but not for some other (control) amino acids. This increase in accepting activity is accompanied by a change in the distribution of the isoaccepting tRNA species corresponding to these three amino acids, but not of the isoacceptors corresponding to some other (control) amino acids. These results are in favor of the theory of functional adaptation of tRNA population.

Alanine↗

PubMedDate not supplied

Organic content of particulate matter in the atmosphere of Ouargla City, Algeria.

The particle-bound organic compounds comprising n-alkanes, n-alkanoic monocarboxylic acids, polynuclear aromatic hydrocarbons (PAH) and nitrated polynuclear aromatic hydrocarbons (NPAH) were investigated in ambient air of the Ouargla city area (Algeria) during a short campaign performed in November 1999. The distribution profile of n-alkanes was consistent with the petrogenic origin of aerosols, suggesting that they were related to torching processes of crude oil refuses in the petroleum extraction field located not far from Ouargla. Instead, the presence of n-alkanoic acids of low molecular weight was indicative of microbial activity experienced by the site. PAH levels were low when compared to other polluted areas. The presence of 2-nitrofluoranthene and 2-nitropyrene, which can result from in-situ nitration of fluoranthene and pyrene, was concurrent with the substantial depletion of the most reactive among PAH, suggesting that photochemical processes influence the composition of the Saharian atmosphere.

Air Pollutants↗

PubMedDate not supplied

[Reference values of urinary mercury in the Italian population].

This paper shows the results of a polycentric study performed to assess the reference values of urinary mercury (U-Hg) in Italian population. 374 subjects from four Italian cities (Bari, Brescia, Genova e Siena) have been examined. A questionnaire on life style, dietary habits, occupational or environmental exposure to Hg and clinical history has been administered to every participant and number and surface of dental amalgams have been verified for all subjects. The determination of U-Hg has been performed on urinary extemporary samples by hydride generation atomic absorption method (HG-AAS); urinary creatinine has been determinated to reduce the intraindividual variability. U-Hg reference values were: 0.21-3.20 micrograms/g creat (5 degrees and 95 degrees percentile) and 0.12-6.04 micrograms/g creat (range). Moreover study results have shown that number and surface of dental amalgams, dietary fish intake and body mass index (BMI) influenced significatively U-Hg excretion. U-Hg reference values from this polycentric study resulted comparable to those assessed in other European countries, whereas the mean U-Hg observed in the referent Italian population was lower.

Adolescent↗