Document content mining for authors' identification task

Przedmiotem niniejszego artykułu jest problem identyfikacji autora na podstawie analizy treści dokumentów. Podejście to opiera się na wyborze odpowiednich cech związanych ze specyficznym użyciem struktur gramatycznych, interpunkcji oraz słownika, a następnie – użycie wybranego algorytmu klasyfikacji. W artykule przedstawiono najpierw różne charakterystyki tekstu, które mogą być użyte w omawianym zagadnieniu, a następnie załączono wyniki eksperymentów obliczeniowych obejmujących wybór cech i badanie skuteczności klasyfikacji w problemie identyfikacji autorów. Artykuł podsumowano wnioskami oraz propozycjami dalszych prac w rozważanej tematyce badawczej

Critical appraisal of clinical trials in oncology — part II

The article is the second part of papers presenting informations useful for an independent analysis of the value of published results of clinical trials in oncology. Based on selected examples of clinical trials, a few attempts of critical appraisal of clinical trial assumptions, construction, and interpretation of their results are given. Several non-inferiority trials are discussed. The paper provides examples of publications in which post hoc analyses, grouping of variables, and multiple comparisons were made. Examples of research with a controversial selection of patients and a comparator, as well as studies whose clinical significance of the obtained results is questionable are presented. The aim of our work is to draw the reader’s attention to selected essential elements of clinical trials and the way of presenting their results in order to facilitate practitioners in the independent evaluation of available publications and rational use of clinical trial results in everyday practice in the future. The article is the second part of papers presenting informations useful for an independent analysis of the value of published results of clinical trials in oncology. Based on selected examples of clinical trials, a few attempts of critical appraisal of clinical trial assumptions, construction, and interpretation of their results are given. Several non-inferiority trials are discussed. The paper provides examples of publications in which post hoc analyses, grouping of variables, and multiple comparisons were made. Examples of research with a controversial selection of patients and a comparator, as well as studies whose clinical significance of the obtained results is questionable are presented. The aim of our work is to draw the reader’s attention to selected essential elements of clinical trials and the way of presenting their results in order to facilitate practitioners in the independent evaluation of available publications and rational use of clinical trial results in everyday practice in the future

Evaluation of the radiopacity of the materials used for sealing root canals with a wide apical gap

Introduction. Optimal canal filling in the apical region poses a challenge for the dentist and determines therapeutic success. The choice of an appropriate material whose physico-chemical properties enable X-ray visualization of the quality of the filling is of great importance. The higher the density of the material, the better the contrast and thus the possibility of correct assessment of the filling. Aim. This study was undertaken to assess radiopacity of materials currently used in endodontics for sealing root canals with a wide apical gap. Material and methods. MTA+ (Cerkamed), Biodentine (Septodont), and gutta-percha with AH Plus paste were used for sealing 27 single-root human teeth. The canals were cleaned with K files to achieve ISO size 40. Next, Gates-Glidden drills size 2 were inserted up to their full working length to enlarge the apex. Each material was used to seal nine canals. X-ray images were taken with the X-Mind DC (Satelec) generator and were recorded, scanned, and analyzed with the Digora digital radiography system. Radiopacity of the image was evaluated on the basis of color change using the 256 levels grayscale. Radiographs of the same roots with a glass plate imitating cheek tissues with a bone fragment were obtained for comparison. Results. The lowest optical density was found for Biodentine. This material demonstrated the smallest X-ray contrast as compared with dentin. The best radiographic visibility was found for gutta-percha with AH Plus paste. In spite of the slightly greater optical density values of MTA+ in comparison with Biodentine, the contrast and radiographic visibility of both materials was poor. Optical density of the materials was reduced in the presence of the glass plate imitating cheek tissues with a bone fragment. Conclusions. MTA+ and Biodentine are characterized by lower optical densities than gutta-percha with AH Plus paste

Krytyczna ocena badań klinicznych w onkologii — część II

Niniejsza praca stanowi drugą część cyklu przedstawiającego informacje pomocne w samodzielnej analizie wartości publikowanych wyników badań klinicznych w onkologii. W odniesieniu do wybranych badań klinicznych w onkologii podano w niej praktyczne przykłady krytycznej oceny ich założeń, konstrukcji, a także interpretacji wyników. Omówiono kilka badań typu non-inferiority. Zamieszczono przykłady publikacji, w których dokonywano analiz post hoc, grupowania zmiennych i wielokrotnych porównań. Przedstawiono także przykłady badań z kontrowersyjnym doborem chorych i komparatora, a także budzących wątpliwości co do tzw. istotności klinicznej uzyskanych wyników. Celem pracy było zwrócenie uwagi czytelnika na wybrane istotne elementy badań klinicznych i sposobu przedstawiania ich wyników, po to aby ułatwić w przyszłości lekarzom praktykom samodzielną ocenę dostępnych publikacji i przez to racjonalne wykorzystanie wyników badań klinicznych w codziennej praktyce.

Critical appraisal of clinical trials in oncology — part I

The main concept of evidence-based medicine is that all therapeutic decisions should be based on results from relevant, credible, and up-to-date clinical trials. Availability of a publication presenting a description of a clinical trial conducted with reliable methods and its high-quality results seems to be an ideal situation from the practitioner’s point of view. However, reading only the abstract or just the author’s conclusions may not always be sufficient to make the right clinical decision. For this purpose, several aspects of the clinical trial should be put under assessment, namely the methodology, its quality, internal and external credibility, clinical and statistical significance, as well as consistency of the results. The ability to perform the proper assessment of clinical trials may prove to be very helpful for practicing oncologists, especially in the case of new, emerging therapies, specific clinical situations, or when salvage treatment is necessary. It is also worth emphasising that the outcome assessment in oncology trials is specific, mainly due to the role of the survival analysis, which is relatively difficult to interpret. In this paper we tried to present in a clear and intelligible way the theoretical basis and subsequent steps in the critical appraisal of methods and results of clinical trials in oncology

Krytyczna ocena badań klinicznych w onkologii — część I

Zgodnie z zasadami medycyny opartej na dowodach (EBM, evidence based medicine) decyzje terapeutyczne powinny być podejmowane na podstawie analizy wyników wiarygodnych badań klinicznych. Dostępność publikacji prezentującej w poprawny sposób metodykę próby klinicznej i jej wyniki o wysokiej jakości wydaje się być sytuacją idealną z punktu widzenia praktykującego lekarza. Jednak czasami przeczytanie samego streszczenia, a zwłaszcza jedynie kilkuzdaniowych wniosków z badania klinicznego może okazać się niewystarczające. Ostatecznie, aby podjąć w pełni świadomą i racjonalną decyzję terapeutyczną, należy szczegółowo ocenić jakość i metodykę badania klinicznego, wiarygodność zewnętrzną i wewnętrzną, istotność statystyczną i kliniczną wyników oraz wewnętrzną i zewnętrzną spójność prezentowanych wniosków. Takie umiejętności oceny i interpretacji wyników badań klinicznych mogą być przydatne w onkologii, zwłaszcza w przypadku innowacyjnych leków lub leczenia pacjentów w szczególnym stanie klinicznym i konieczności rozważania dostępu do leczenia ratunkowego. Warto też podkreślić specyfikę oceny do leczenia punktów końcowych w badaniach onkologicznych, w których wyjątkową rolę odgrywa dość trudna w interpretacji analiza przeżycia. W artykule przedstawione zostały w sposób przystępny podstawy teoretyczne oraz kolejne kroki krytycznej oceny metodyki i wyników badań klinicznych prowadzonych w obszarze onkologii

Bevacizumab or standard chemotherapy in previously treated patients with metastatic colorectal cancer — a systematic review

Introduction. The BRAF V600E mutation (BRAFmt) occurring in the metastatic colorectal cancer (mCRC) patients is associated with poorer prognosis, in comparison to the wild-type variant of the BRAF gene (BRAFwt). Aim of this work was to assess the clinical efficacy of bevacizumab (BEVA) or standard chemotherapy (ChT) in the 2nd or further lines of treatment in mCRC BRAFmt population.  Material and methods. MEDLINE/PubMed, Embase and Cochrane CENTRAL databases were systematically searched. The reference lists of relevant studies were also checked.  Results. 6 eligible trials were identified: MOMA (BEVA ± ChT), allowing for limited overall survival (OS) assessment, WJOG 6210G (BEVA + FOLFIRI), RAISE and 20050181 (FOLFIRI), PICCOLO and Spindler 2013 (irinotecan monotherapy). None of those trials were designed for the treatment evaluation in BRAFmt population. Available evidence was restricted to limited analyses in small subgroups (from a few to several dozens of patients), occasionally comprising RAS gene mutation (RASmt) as well. Based on the identified studies, the comparison of BEVA ± ChT vs. ChT or among different ChTs in BRAFmt population was not feasible. In case of BEVA (MOMA), OS hazard ratio (HR) for BRAFmt vs. BRAFwt was 1.52 (95% CI: 0.79–2.89) with difference in medians equal to 12.1 months (19.2 vs. 31.3 months, respectivelly), and BRAFmt or RASmt patients had median OS lower by 7.9 months and median progression free survival (PFS) by 3.0 months in WJOG 6210G trial. In case of ChT, median PFS was lower in BRAFmt by 12–67% (HRs range: 1.01–5.3), and median OS by 34–73% (HRs range: 1.05–5.00).  Conclusions. Due to limited clinical evidence, assessment of further lines of treatment in BRAFmt mCRC patients is uncertain, however existing data consistently suggest lower effectiveness of BEVA ± ChT or ChT in BRAFmt, than in BRAFwt subgroup. Hopefully, combining anti-EGFR therapies with BRAF/MEK inhibitor is expected to improve prognosis of those patients.Introduction. The BRAF V600E mutation (BRAFmt) occurring in the metastatic colorectal cancer (mCRC) patients is associated with poorer prognosis, in comparison to the wild-type variant of the BRAF gene (BRAFwt). Aim of this work was to assess the clinical efficacy of bevacizumab (BEVA) or standard chemotherapy (ChT) in the 2nd or further lines of treatment in mCRC BRAFmt population.Material and methods. MEDLINE/PubMed, Embase and Cochrane CENTRAL databases were systematically searched. The reference lists of relevant studies were also checked.Results. 6 eligible trials were identified: MOMA (BEVA ± ChT), allowing for limited overall survival (OS) assessment, WJOG 6210G (BEVA + FOLFIRI), RAISE and 20050181 (FOLFIRI), PICCOLO and Spindler 2013 (irinotecan monotherapy). None of those trials were designed for the treatment evaluation in BRAFmt population. Available evidence was restricted to limited analyses in small subgroups (from a few to several dozens of patients), occasionally comprising RAS gene mutation (RASmt) as well. Based on the identified studies, the comparison of BEVA ± ChT vs. ChT or among different ChTs in BRAFmt population was not feasible. In case of BEVA (MOMA), OS hazard ratio (HR) for BRAFmt vs. BRAFwt was 1.52 (95% CI: 0.79–2.89) with difference in medians equal to 12.1 months (19.2 vs. 31.3 months, respectivelly), and BRAFmt or RASmt patients had median OS lower by 7.9 months and median progression free survival (PFS) by 3.0 months in WJOG 6210G trial. In case of ChT, median PFS was lower in BRAFmt by 12–67% (HRs range: 1.01–5.3), and median OS by 34–73% (HRs range: 1.05–5.00).Conclusions. Due to limited clinical evidence, assessment of further lines of treatment in BRAFmt mCRC patients is uncertain, however existing data consistently suggest lower effectiveness of BEVA ± ChT or ChT in BRAFmt, than in BRAFwt subgroup. Hopefully, combining anti-EGFR therapies with BRAF/MEK inhibitor is expected to improve prognosis of those patients