1,720,978 research outputs found
HPLC analysis of the antidepressant trazodone and its main metabolite m-CPP in human plasma
No full textThe present paper deals with the development of a rapid and feasible high-performance liquid chromatographic method for the determination of trazodone and its main active metabolite 3-(1-clorophenyl)piperazine (m-CPP) in human plasma. Trazodone is a second-generation antidepressant with serotonin antagonist activity. The metabolite seems to be involved in the onset of some side effects of trazodone therapy, thus its determination is very important during therapeutic drug monitoring. Separation was achieved using a C8 reversed-phase column and a mobile phase composed of aqueous phosphate buffer (70%), containing triethylamine, at pH 3.5 and acetonitrile (30%). The UV detector was set at 255 nm and loxapine was used as the internal standard. An original pre-treatment procedure of plasma samples was developed, based on solid-phase extraction with C8 reversed phase cartridges (50mg, 1 mL). The obtained extraction yields values were higher than 90% and precision, expressed as R.S.D., was lower than 5.6%. The method was successfully applied to plasma samples from depressed patients undergoing therapy with trazodone; accuracy results were satisfactory (recovery >91%). Thus, the method seems to be suitable for the therapeutic drug monitoring of trazodone and its main active metabolite in depressed patients' plasma
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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Emotional, Behavioral, and Physical Health Consequences in Caregivers of Children with Cancer: A Network Analysis Differentiation in Mothers’ and Fathers’ Reactivity
Full text linkBackground: Pediatric cancer presents mental and physical challenges for patients and their caregivers. However, parental distress has been understudied despite its negative impact on quality of life, disability, and somatic disorders. Parents of oncopediatric patients experience high levels of suffering with their resilience tested throughout their children’s illness. Identifying at-risk parents and offering specific treatments is crucial and urgent to prevent or alleviate negative outcomes. Methods: This study used statistical and network analyses to examine symptom patterns assessed by the Kellner Symptom Questionnaire in 16 fathers and 23 mothers at different time points: diagnosis, treatment, and discharge. Results: The results indicated significantly higher distress levels in parents of oncopediatric children compared to the control reference population. Gender-specific differences in symptom profiles were observed at each time point, and symptoms showed a gradual but non-significant decrease over time. Conclusions: The network analysis yielded valuable insights that, when applied in clinical practice, can guide the implementation of timely treatments to prevent and manage parental distress, thus addressing long-term, stress-related issues in primary caregivers of children diagnosed and treated for cancer
Redefining operant conditioning of escape behaviour in lymnaea stagnalis
Full text linkThe escape behaviour is one of the many behavioural responses that can be operantly conditioned in a stimulus-dependent manner in both vertebrates and invertebrates. By exposing the pond snail Lymnaea stagnalis repeatedly to a negative reinforcement its natural tendency to explore its surroundings can be operantly conditioned in both adult and aged snails. When adult snails were trained with 100 mM of KCl their number of escapes was significantly decreased and the latency to first escape was significantly increased. Our behavioural protocol allowed us to investigate memory acquisition, consolidation, and retrieval in pre-and post-training sessions over different days. From the 3rd day of training the learned response was strengthened: the number of the escapes in the post-test session remained significantly reduced even when animals were presented with distilled water. Moreover, adult snails exposed to the negative reinforcement for at least 4 days started to escape significantly less than the control group also in the pre-test session. This effect became more pronounced in the following days and was accompanied by a significant increase in the latency to first escape at the beginning of the pre-test on day 6 and 7. Aged snails, instead, showed selective deficiencies when operantly conditioned: memory retention appeared only after 7 days, while memory retrieval could not be induced. This redefined paradigm can help unravelling a variety of sophisticated cognitive phenomena in L. stagnalis and could be employed also to study the basis of memory impairment occurring during neuro-aging
Digital Phenotyping and Dynamic Monitoring of Adolescents Treated for Cancer to Guide Intervention: Embracing a New Era
Full text linkElectronic nose and chiral-capillary electrophoresis in evaluation of the quality changes in commercial green tea leaves during a long-term storage.
No full textElectronic nose and capillary electrophoresis were applied in quality control of green tea samples subjected to long-term storage. Twelve representative green teas were considered, available as an "aged" (tea leaves stored during a long-term period of two years) and/or "not aged" (fresh products) samples. Their infusions were analyzed by an electronic nose, equipped with an array of six metal oxide semiconductor (MOS) sensors to obtain olfactive fingerprints of the volatile compounds in the infusions headspace. Upon training and chemometric analysis of acquired data (linear discriminant analysis), the electronic nose was found to be able in correctly classifying unknown samples as "aged" or "not aged". Concomitantly, the infusion samples were analyzed by Cyclodextrin-modified Micellar Electrokinetic Chromatography (CD-MEKC) for determination of catechins. The analysis of seven most represented catechins and the methylxanthines theobromine and caffeine revealed a general loss of the polyphenols in each of the considered aged samples (up to 45%, w/w). In addition, the applied enantioselective method based on (2-hydroxypropyl)-beta-cyclodextrin (HP-beta CD) as chiral selector, was exploited for the estimation of (+)-Gallocatechin in the presence of (-)-Gallocatechin; the latter, as the non-native enantiomer, can be associated to the epimerisation of (-)-Epigallocatechin and was assumed as a marker occurring in case of uncorrected storage conditions of tea leaves. Interestingly, it was observed that epimerization did not significantly occur during aging. The application of CD-MEKC and electronic nose allowed for a fast characterization of green teas taking into account that the aroma is a decisive parameter for the acceptance of the product, whereas the catechins content is associated to the biological value
Vortioxetine Prevents Lipopolysaccharide-Induced Memory Impairment Without Inhibiting the Initial Inflammatory Cascade
Full text linkVortioxetine is a novel multimodal antidepressant that modulates a wide range of neurotransmitters throughout the brain. Preclinical and clinical studies have shown that vortioxetine exerts positive effects on different cognitive domains and neuroprotective effects. Considering the key role of microglial cells in brain plasticity and cognition, we aimed at investigating the effects of pretreatment with vortioxetine in modulating behavioral and molecular effects induced by an immune challenge: peripheral injection of lipopolysaccharide (LPS). To this purpose, C57BL/6J male mice were first exposed to a 28-day standard diet or vortioxetine-enriched diet, which was followed by an acute immune challenge with LPS. Sickness symptoms and depressive-like behaviors (anhedonia and memory impairment) were tested 6 and 24 h after exposure to LPS, respectively. Moreover, the expressions of markers of immune activation and M1/M2 markers of microglia polarization were measured in the dorsal and ventral parts of the hippocampus. The pretreatment with vortioxetine did not affect both LPS-induced sickness behavior and anhedonia but prevented the deficit in the recognition memory induced by the immune challenge. At the transcriptional level, chronic exposure to vortioxetine did not prevent LPS-induced upregulation of proinflammatory cytokines 6 h after the immune challenge but rather seemed to potentiate the immune response to the challenge also by affecting the levels of expression of markers of microglia M1 phenotype, like cluster of differentiation (CD)14 and CD86, in an area-dependent manner. However, at the same time point, LPS injection significantly increased the expression of the M2 polarization inducer, interleukin 4, only in the hippocampus of animals chronically exposed to vortioxetine. These results demonstrate that a chronic administration of vortioxetine specifically prevents LPS-induced memory impairment, without affecting acute sickness behavior and anhedonia, and suggest that hippocampal microglia may represent a cellular target of this novel antidepressant medication. Moreover, we provide a useful model to further explore the molecular mechanisms specifically underlying cognitive impairments following an immune challenge
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