Biomedical subjects

Ana Castillo

Publications and source records attributed to Ana Castillo.

3 recordsLinked to original sources

PubMed2006

Interference of antibiotics in the growth curves of oral streptococci.

The growth curve interference (GCI) induced by different antibiotics was studied using reference strains of oral streptococci. This parameter may prove to be useful in preventing subacute endocarditis of odontological origin in high-risk patients. The growth curves using different concentrations of antibiotics and with an initial optical density (OD) of 0.05 +/- 0.01 were observed until an OD of 0.9-1.0 was reached. The GCI was defined as the lowest concentration of antibiotic that modified the growth curve with respect to a control without antibiotic. The GCI values were then compared with the minimum inhibitory concentration (MIC) values. In all cases, interference in the growth curves was at least one concentration lower than the MIC in a time ranging from 4-6 h.

Anti-Bacterial Agents↗

PubMed2006

Gamma-hydroxybutyric acid affects the acquisition and reinstatement of cocaine-induced conditioned place preference in mice.

Cocaine addicts very often use different combinations of cocaine and other drugs of abuse such as gamma-hydroxybutyric acid. The objective of the present work was to evaluate the impact of gamma-hydroxybutyric acid administration on the rewarding actions of cocaine, using the conditioned place preference procedure. Cocaine-induced conditioned place preference (50 mg/kg) was studied after pairing this drug with different gamma-hydroxybutyric acid doses (6.25, 12.5, 25, 50 and 100 mg/kg) during either the acquisition or the expression phase of the procedure. After conditioned place preference had been established, and the preference was extinguished, a reinstatement was induced by a dose of cocaine half of that used to produce conditioning, or by gamma-hydroxybutyric acid alone or by both drugs together. The doses of 12.5 and 100 mg/kg of gamma-hydroxybutyric acid blocked the acquisition of cocaine-induced conditioned place preference, and no dose affected the expression of this conditioning. Reinstatement was abolished only with the dose of 25 mg/kg gamma-hydroxybutyric acid, which did not reinstate the preference by itself. This is the first study evaluating the effects of gamma-hydroxybutyric acid on the rewarding properties of cocaine using the conditioned place preference procedure. The principal conclusion of the study is that gamma-hydroxybutyric acid does not enhance the rewarding effect of cocaine, and within a narrow margin of effective doses, blocks the acquisition and reinstatement of cocaine-induced preference.

Anesthetics, Intravenous↗

PubMed1999

A new biotyping method for Streptococcus mutans with the API ZYM system.

OBJECTIVE: To test a new system for the biotyping of Streptococcus mutans, based on the measurement of enzyme activity, and to investigate the relationship between biotype and in vitro susceptibility to seven clinically useful antibiotics. METHODS: In total, 160 oral isolates of S. mutans were classified into different biotypes with the APIZYM test for enzyme activity, excluding results that were positive or negative in >80% of the strains. The susceptibility of all 160 strains to amoxycillin, cefazolin, erythromycin, clindamycin, vancomycin, teicoplanin and imipenem was tested by dilution in a solid medium. Statistical analysis of susceptibility (mean minimum inhibitory concentrations (MICs)) was based on chi-squared tests. RESULTS: Eight different biotypes (1-8) were identified on the basis of three kinds of enzyme activity: valine aryl amidase, acid phosphatase and alpha-galactosidase. Biotype 5 was found to be the most common. The mean MIC values showed strains belonging to biotype 4 to be the most susceptible to amoxycillin, cefazolin and erythromycin, whereas biotype 1 was the least susceptible to teicoplanin. CONCLUSIONS: The proposed biotyping method, which is relatively fast and simple to perform, provided reproducible results, and may contribute to clinically effective treatment of S. mutans infections.

Journal Article↗