1,720,964 research outputs found
Brain microsurgery in glioblastoma mouse models for local administration of Temozolomide-loaded hydrogels
Get PDFGlioblastoma is the most common and aggressive malignant tumor of the central nervous system in adults. It can occur at any age, but 70% of patients are diagnosed between the ages of 45 and 70. These tumors show a high proliferation rate with diffuse infiltration of adjacent brain tissue and a rapidly progressive course (around 2-3 months).Tumors are usually located in the cerebral hemispheres, but can be found throughout the central nervous system. The first choice treatment is usually surgical, both to confirm the diagnosis through a biopsy, and to remove the tumor mass as extensively as possible. Unfortunately, a complete resection is very infrequent, as cancer cells usually infiltrate the surrounding brain. Therefore, the goal of surgery is only to obtain a histological diagnosis, decrease the symptoms due to the increase in intracranial pressure and prolong survival. Surgery is usually followed by radiation therapy and chemotherapy but there is a treatment gap of 2 to 3 weeks between tumor resection and subsequent therapies. The post-surgical therapeutic standard currently consists of a chemo-radiotherapy association with Temozolomide (TMZ) for the entire duration of radiotherapy, followed by adjuvant TMZ. However, tumor recurrences due to residual infiltrative cells at the resection margin are extremely common.
This study aims at developing a mouse model of glioblastoma recurrences by a surgical protocol of partial tumor removal in mouse brains, for subsequent on-site treatment with thermogel, a “smart” material loaded with TMZ. For this purpose, the U87MG human glioblastoma cell line was chosen for the development of a mouse orthotopic model in the striatum, a subcortical region of the brain. Once tumors of sufficient size were obtained, a microsurgery protocol with craniotomy was optimized for the partial removal of the tumor mass in order to study the phenomenon of recurrence. The cavity thus obtained was filled with thermogel containing TMZ. The effect due to this treatment was confirmed by two different types of analysis: histological and bioluminescent. The histological analysis allowed us to verify the correct inoculation region of the tumor cells and to verify their growth. Furthermore, by measuring the tumor present in the brain slices removed from treated and untreated mice, we were able to measure the area of each tumor with a specific software, verifying the effectiveness of the treatment. To confirm obtained data, we carried out another type of analysis, using the IVIS In Vivo Imaging System, usingU87MG cells stably expressing the firefly enzyme luciferase from Luciola Italica (Red-FLuc). By recording the bioluminescence emitted by the tumor cells inoculated inside the brain of the mice, following an adequate stimulus, we confirmed the effect of the treatment of the thermogel containing the chemotherapeutic
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
NCOA4 links iron bioavailability to DNA metabolism
No full textIron is essential for deoxyribonucleotides production and for enzymes containing an Fe-S cluster involved in DNA replication and repair. How iron bioavailability and DNA metabolism are coordinated remains poorly understood. NCOA4 protein mediates autophagic degradation of ferritin to maintain iron homeostasis and inhibits DNA replication origin activation via hindrance of the MCM2-7 DNA helicase. Here, we show that iron deficiency inhibits DNA replication, parallel to nuclear NCOA4 stabilization. In iron-depleted cells, NCOA4 knockdown leads to unscheduled DNA synthesis, with replication stress, genome instability, and cell death. In mice, NCOA4 genetic inactivation causes defective intestinal regeneration upon dextran sulfate sodium-mediated injury, with DNA damage, defective cell proliferation, and cell death; in intestinal organoids, this is fostered by iron depletion. In summary, we describe a NCOA4-dependent mechanism that coordinates iron bioavailability and DNA replication. This function prevents replication stress, maintains genome integrity, and sustains high rates of cell proliferation during tissue regeneration
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
SARS-CoV-2 epidemiological trend before vaccination era: a seroprevalence study in Apulia, Southern Italy, in 2020
Get PDFAIM: The present study aimed at assessing the prevalence of antibodies against SARS-CoV-2 in the general population in the province of Bari (Apulia region, Southern Italy) during the year 2020. SUBJECT AND METHODS: In this study, 1325 serum samples collected from January to December 2020 were tested for the presence of IgM and IgG antibodies against whole-virus SARS-CoV-2 antigen by commercial ELISA. Positive samples were further tested by in-house ELISA for the detection of anti-receptor binding domain (RBD) IgM and IgG antibodies and by micro-neutralization (MN) assay for the detection of neutralizing antibody. RESULTS: One hundred (7.55%) samples had the presence of at least one antibody class against SARS-CoV-2 by commercial ELISA, of which 88 (6.6%) showed IgG and 19 (1.4%) showed IgM antibodies. The proportion of samples with IgG antibodies increased from 1.9% in January–February to 9.6% in November–December, while no significant increase was observed for IgM. When tested by in-house ELISA and MN assay, 17.0% and 31.6% were found positive to RBD IgG and RBD IgM, respectively, while 12.0% showed neutralizing antibody. CONCLUSION: The proportion of samples with SARS-CoV-2 IgG antibodies increased during 2020, especially in the second half of the year, consistent with data reported by the routine epidemiological surveillance of SARS-CoV-2 cases. Despite the high number of reported cases, the seroprevalence values are relatively low, and only a small proportion of samples had neutralizing antibodies. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10389-023-01834-3
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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