1,721,038 research outputs found
Funzionalita' dell'asse ipotalamo-ipofisi-surrene in adolescenti eroinomani. Effetto dell'ACTH 1-17 sui livelli di prolattina.
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Analysis of polymorphism in genes involved in serotonergic and dopaminergic transmission in male heroin-dependent subjects: behavioural and personality correlates
No full textEndogenous cortisol effects on hyperprolactinemia induced by acute and chronic morphine administration.
No full textOriginal HPLC-F method for the simultaneous determination of cocaine and two metabolites in dried blood spots and plasma
No full textIntroduction: Cocaine (methyl (1R,2R,3S,5S)-3-(benzoyloxy)-8-methyl-8-azabicyclo[3.2.1]octane-2-carboxylate) is currently the second most widespread illicit drug in Western countries, after Cannabis. In Europe in particular, its use has been increasing in the past few years, following a pattern similar to that of the USA in the 1980s. This severe trend has attracted much attention from governments and health agencies and is creating much concern regarding its negative impact on people’s and in particular on adolescent’s health. It is evident the need for reliable and easily applied analytical methods for the determination of cocaine in abusers.
Methods: An original chromatographic method coupled to spectrofluorimetric detection (HPLC-F) is presented herein for the simultaneous determination in dried blood spots (DBS) and plasma of cocaine and two important metabolites, namely benzoylecgonine (its main metabolite) and cocaethylene (the active metabolite formed in the presence of ethanol).
Results: The analysis was carried out on a C8 column, using a mobile phase containing phosphate buffer and acetonitrile. Native analyte fluorescence was monitored at 315 nm, while exciting at 230 nm.
For DBS, sample pre-treatment was carried out by solvent extraction; for plasma, by solid phase extraction (SPE) with C8 cartridges. Extraction yields (> 91%) and precision values (RSD < 4.8%) were highly satisfactory on both matrices. The method was successfully applied to DBS and plasma samples collected from some cocaine users, both with and without concomitant ethanol intake.
Conclusions: The method has demonstrated to be suitable for the monitoring of cocaine/ethanol use by means of DBS and plasma testing. Moreover, it represents a significant improvement over existing ones, since it has the fundamental advantage of allowing the simultaneous quantification of cocaine, benzoylecgonine and cocaethylene, thus making it possible to detect the simultaneous intake of both cocaine and ethanol
Distribution of serotonin, 5-hydroxyindolacetic acid and homovanillic acid in biological fluids of psycotic patients treated with clozapine
No full text1. Introduction. The dopaminergic and serotoninergic systems are known to be related to several mental illnesses such as schizophrenia, depression and affective disorders. A change in levels of neurotransmitters including dopamine and serotonin (and/or their metabolites) may lead to pathological processes with specific clinical manifestations. The introduction of the atypical antipsychotics acting on multiple neurotransmitters has improved therapeutic results. In particular, clozapine, the parent drug of the atypical antipsychotics, is more effective for reducing symptoms of schizophrenia than the older typical antipsychotics because of its profile of binding to serotonergic as well as dopamine receptors.
2. Materials and Methods. A high-performance liquid chromatographic method has been developed for the simultaneous determination of serotonin, 5-hydroxyindolacetic and homovanillic acids in dried blood spots and in platelet poor and rich plasma samples. Analyses were carried out on a C18 reversed-phase column using a mobile phase composed of methanol and aqueous citrate buffer. Coulometric detection was used, operating at +0.400 V. For the clean-up of the biological samples a novel solid-phase extraction procedure, based on mixed-mode reversed-phase – strong anion exchange cartridges, was implemented.
3. Results. The analytical method was linear over the on-column concentration range of 0.1 - 22.5 ng/mL for serotonin and 5-hydroxyindolacetic acid and of 0.25 - 22.5 ng/mL for homovanillic acid. Extraction yields of the analytes from all these matrices were satisfactory, being always higher than 89.0 %. Results were satisfactory in terms of sensitivity, precision, selectivity and accuracy.
4. Conclusion. The analytical method was successfully applied to the analysis of serotonin, 5-hydroxyindolacetic and homovanillic acids in human platelet poor and rich plasma samples and to dried blood spots from volunteers and some psychotic patients treated with clozapine. Assays are currently in progress to apply this method to biological fluids from numerous psychiatric patients for studies regarding neuroendocrine responses
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Fast analysis of catecholamine metabolites MHPG and VMA in human plasma by HPLC with fluorescence detection and a novel SPE procedure
No full textA fast and sensitive high-performance liquid chromatographic method has been developed for the determination in human plasma of MHPG (3-methoxy-4-hydroxyphenylethylenglycol) and VMA (vanillyl mandelic acid), the main metabolites of epinephrine and norepinephrine. Analyses were carried out at 325 nm while exciting at 285 nm on a reversed-phase column (Atlantis C18, 150×4.6 mm I.D., 5 μm) using a mobile phase composed of 2% methanol and 98% aqueous citrate buffer at pH 3.0. A careful solid-phase extraction procedure, based on mixed-mode reversed phase - strong anion exchange Oasis cartridges (MAX, 30 mg, 1 mL), was developed for the pre-treatment of plasma samples. Extraction yields were satisfactory, always higher than 90%. Calibration curves were linear over the 0.2-40.0 ng/mL concentration range for MHPG and over the 0.5-40.0 ng/mL concentration range for VMA. The method was successfully applied to plasma samples of former drug users undergoing detoxification therapy and subjects “at risk” of developing drug addiction
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