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57 result(s) for "Villela, Luis"
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autoRA: An Algorithm to Automatically Delineate Reference Areas—A Case Study to Map Soil Classes in Bahia, Brazil
The reference area (RA) approach has been frequently used in soil surveying and mapping projects, since it allows for reduced costs. However, a crucial point in using this approach is the choice or delineation of an RA, which can compromise the accuracy of prediction models. In this study, an innovative algorithm that delineates RA (autoRA—automatic reference areas) is presented, and its efficiency is evaluated in Sátiro Dias, Bahia, Brazil. autoRA integrates multiple environmental covariates (e.g., geomorphology, geology, digital elevation models, temperature, precipitation, etc.) using the Gower’s Dissimilarity Index to capture landscape variability more comprehensively. One hundred and two soil profiles were collected under a specialist’s manual delineation to establish baseline mapping soil taxonomy. We tested autoRA coverages ranging from 10% to 50%, comparing them to RA manual delineation and a conventional “Total Area” (TA) approach. Environmental heterogeneity was insufficiently sampled at lower coverages (autoRA at 10–20%), resulting in poor classification accuracy (0.11–0.14). In contrast, larger coverages significantly improved performance: 30% yielded an accuracy of 0.85, while 40% and 50% reached 0.96. Notably, 40% struck the best balance between high accuracy (kappa = 0.65) and minimal redundancy, outperforming RA manual delineation (accuracy = 0.75) and closely matching the best TA outcomes. These findings underscore the advantage of applying an automated, diversity-driven strategy like autoRA before field campaigns, ensuring the representative sampling of critical environmental gradients to improve DSM workflows.
Photodynamic therapy in root canals contaminated with Enterococcus faecalis using curcumin as photosensitizer
The aim of the study was to evaluate the photodynamic therapy (PDT) effect on root canals contaminated with Enterococcus faecalis using a light emitting diode (LED) light and a curcumin solution (CUR) as photosensitizer (PS). Eighty root canals from uniradicular human teeth were prepared with Protaper Universal rotary system and contaminated with E. faecalis for 21 days. They were divided as: GIa-PDT (CUR, pre-irradiation for 5 + 5 min of irradiation); GIb-PDT (CUR, pre-irradiation for 5 + 10 min of irradiation); GIIa-(CUR, pre-irradiation for 5 + 5 min without irradiation); GIIb-(CUR pre-irradiation for 5 + 10 min of irradiation); GIIIa-(physiological solution and irradiation for 5 min); and GIIIb-(physiological solution and irradiation for 10 min); positive and negative control groups. Collections from root canals were made at time intervals of 21 days after contamination, immediately after treatment, and 7 days after treatment, and submitted to colony forming units per milliter (CFU mL −1 ) counts. The data were submitted to ANOVA and Tukey multiple comparison tests, at a level of significance of 5 %. In the immediate post-treatment collection, group GIa showed greater bacterial reduction in comparison with GIIa, GIIb, GIIIa, GIIIb, and positive control ( P  < 0.05). At 7 days post-treatment, GIa showed significant bacterial reduction only in comparison with GIIIa ( P  < 0.05). Curcumin as sensitizer was effective by 5 min LED irradiation but not by 10 min irradiation PDT using LED light, and curcumin as PS was not effective in eliminating E. faecalis . No difference was observed for periods of irradiation.
Sphingolipids and Lymphomas: A Double-Edged Sword
Lymphomas are a highly heterogeneous group of hematological neoplasms. Given their ethiopathogenic complexity, their classification and management can become difficult tasks; therefore, new approaches are continuously being sought. Metabolic reprogramming at the lipid level is a hot topic in cancer research, and sphingolipidomics has gained particular focus in this area due to the bioactive nature of molecules such as sphingoid bases, sphingosine-1-phosphate, ceramides, sphingomyelin, cerebrosides, globosides, and gangliosides. Sphingolipid metabolism has become especially exciting because they are involved in virtually every cellular process through an extremely intricate metabolic web; in fact, no two sphingolipids share the same fate. Unsurprisingly, a disruption at this level is a recurrent mechanism in lymphomagenesis, dissemination, and chemoresistance, which means potential biomarkers and therapeutical targets might be hiding within these pathways. Many comprehensive reviews describing their role in cancer exist, but because most research has been conducted in solid malignancies, evidence in lymphomagenesis is somewhat limited. In this review, we summarize key aspects of sphingolipid biochemistry and discuss their known impact in cancer biology, with a particular focus on lymphomas and possible therapeutical strategies against them.
Optimizing resources: low-dose nivolumab combinations in the management of relapsed/refractory Hodgkin lymphoma
Up to one-third of patients with classical Hodgkin lymphoma (cHL) are not responsive to first-line therapy or eventually relapse. Immune checkpoint inhibitors (ICIs) have been successfully employed to treat relapsed/refractory cHL (r/r cHL) but place patients at risk of financial toxicity. Early-phase trials and observational data suggest that low doses of ICIs may achieve similar results to those obtained with high doses. In this study, we report a single-center experience using low-dose nivolumab (LD-Nivo) in different combinations for r/r cHL, including monotherapy, LD-Nivo plus brentuximab vedotin (BV), and LD-Nivo plus chemotherapy. The primary outcome was to assess the efficacy of LD-nivo in patients with r/r cHL. We included 23 consecutive patients (median age 27 years; 57% female). LD-Nivo was prescribed in 40, 100, and 140 mg fixed doses Q2W. Survival analysis was performed employing the Kaplan–Meier method. 73% of patients achieved an overall response, 43% complete response, and 30% partial response. One-year overall survival was 94.4% (95% CI, 0.84–1), and the 1-year progression-free survival was 89.4% (95% CI, 0.77–1). OS and PFS were similar accross combinations. The median dose of nivolumab was 0.78 mg/kg (range, 0.62–1.11), and the median number of cycles until a response was documented was 6 (range, 2–9). During follow-up, 18 patients received transplantation (11 autologous, 6 allogeneic). No statistically significant differences in survival or response were detected between nivolumab combinations or doses. Adverse events were observed in 61% of the patients, with none grade 3–4. LD-Nivo demonstrated promising results in relapsed/refractory HL, highlighting its potential as a cost-effective treatment option. Further research is needed to validate these findings and guide clinical practice.
Prevalence and survival outcomes of adult T-cell leukemia/lymphoma in Latin America: A multicenter cohort study and recommendations to improve diagnosis and outcomes
Although adult T-cell leukemia/lymphoma (ATL) has a higher burden in Latin America compared to North American or European countries, few studies have described the outcomes of this disease. We estimated the hospital-based prevalence and overall survival (OS) of ATL. We conducted a cohort study among patients aged ≥ 18 years with pathologically diagnosed mature T-cell lymphoma across 11 Latin American countries from 2000 to 2023 by pooling data from 3 hospital-based registries. We used the Kaplan-Meier method to estimate survival outcomes. Among 1963 patients with mature T-cell lymphoma, the pooled prevalence of ATL was 17 % (n = 329; 95 % confidence interval [CI]=15–18 %), with the highest observed in Peru (n = 158; 38 %, 95 % CI=33–43 %) and Colombia (n = 17; 29 %, 95 % CI=18–41 %). Over time, ATL cases only increased significantly in Peru, from 14 % in 2000–2004 to 58 % in 2019–2023 (Ptrend<0.001). With a median follow-up of 37 months (95 % CI=30–54 months), the 3-year OS of ATL was 25 % (95 % CI=20–32 %), and the median OS was 9 months (95 % CI=8–12 months). OS did not differ across countries (range 19–47 %, P = 0.210). Patients with lymphomatous ATL had worse outcomes than those with PTCL-NOS only in Peru (Pheterogeneity=0.029). Our findings indicate a higher ATL prevalence in Latin America than previously reported in North America or Europe, likely due to differences in HTLV-1 endemicity and diagnostic practices. The similar and poor survival rates across countries underscore the need for targeted interventions to improve patient outcomes. We propose expert-based research priorities and suggest further epidemiological validation studies. •ATL prevalence in Latin America is likely higher than in other regions.•Survival rates for ATL patients remain poor across countries.•Lack of HTLV screening may lead to misdiagnosis of ATL as PTCL-NOS.•Population- based validation studies and expert-based research priorities and are needed to improve outcomes•Collaborative capacity-building will accelerate discovery and enhance ATL-related health outcomes globally
Acute Myeloid Leukaemia
The current treatment of patients with acute myeloid leukaemia yields poor results, with expected cure rates in the order of 30-40% depending on the biological characteristics of the leukaemic clone. Therefore, new agents and schemas are intensively studied in order to improve patients' outcomes. This review summarizes some of these new paradigms, including new questions such as which anthracycline is most effective and at what dose. High doses of daunorubicin have shown better responses in young patients and are well tolerated in elderly patients. Monoclonal antibodies are promising agents in good risk patients. Drugs blocking signalling pathways could be used in combination with chemotherapy or in maintenance with promising results. Epigenetic therapies, particularly after stem cell transplantation, are also discussed. New drugs such as clofarabine and flavopiridol are reviewed and the results of their use discussed. It is clear that many new approaches are under study and hopefully will be able to improve on the outcomes of the commonly used '7+3' regimen of an anthracycline plus cytarabine with daunorubicin, which is clearly an ineffective therapy in the majority of patients. [PUBLICATION ABSTRACT]
Acute Myeloid Leukaemia
The current treatment of patients with acute myeloid leukaemia yields poor results, with expected cure rates in the order of 30–40% depending on the biological characteristics of the leukaemic clone. Therefore, new agents and schemas are intensively studied in order to improve patients’ outcomes. This review summarizes some of these new paradigms, including new questions such as which anthracycline is most effective and at what dose. High doses of daunorubicin have shown better responses in young patients and are well tolerated in elderly patients. Monoclonal antibodies are promising agents in good risk patients. Drugs blocking signalling pathways could be used in combination with chemotherapy or in maintenance with promising results. Epigenetic therapies, particularly after stem cell transplantation, are also discussed. New drugs such as clofarabine and flavopiridol are reviewed and the results of their use discussed. It is clear that many new approaches are under study and hopefully will be able to improve on the outcomes of the commonly used ‘7+3’ regimen of an anthracycline plus cytarabine with daunorubicin, which is clearly an ineffective therapy in the majority of patients.
Discriminant analysis and machine learning approach for evaluating and improving the performance of immunohistochemical algorithms for COO classification of DLBCL
Background Diffuse large B-cell lymphoma (DLBCL) is classified into germinal center-like (GCB) and non-germinal center-like (non-GCB) cell-of-origin groups, entities driven by different oncogenic pathways with different clinical outcomes. DLBCL classification by immunohistochemistry (IHC)-based decision tree algorithms is a simpler reported technique than gene expression profiling (GEP). There is a significant discrepancy between IHC-decision tree algorithms when they are compared to GEP. Methods To address these inconsistencies, we applied the machine learning approach considering the same combinations of antibodies as in IHC-decision tree algorithms. Immunohistochemistry data from a public DLBCL database was used to perform comparisons among IHC-decision tree algorithms, and the machine learning structures based on Bayesian, Bayesian simple, Naïve Bayesian, artificial neural networks, and support vector machine to show the best diagnostic model. We implemented the linear discriminant analysis over the complete database, detecting a higher influence of BCL6 antibody for GCB classification and MUM1 for non-GCB classification. Results The classifier with the highest metrics was the four antibody-based Perfecto–Villela (PV) algorithm with 0.94 accuracy, 0.93 specificity, and 0.95 sensitivity, with a perfect agreement with GEP (κ = 0.88, P  < 0.001). After training, a sample of 49 Mexican-mestizo DLBCL patient data was classified by COO for the first time in a testing trial. Conclusions Harnessing all the available immunohistochemical data without reliance on the order of examination or cut-off value, we conclude that our PV machine learning algorithm outperforms Hans and other IHC-decision tree algorithms currently in use and represents an affordable and time-saving alternative for DLBCL cell-of-origin identification.
Características de actividad física, tiempo sedentario, composición corporal y rehabilitación cardiaca en adultos con enfermedad coronaria en Puerto Rico
Este estudio incluyó 36 adultos (8 mujeres, 28 hombres; edad = 72.6 (DE = 5.5) años) con enfermedad coronaria en Puerto Rico. La actividad física (AF) moderada a vigorosa promedio fue 50.3 (DE = 109.9) minutos/semana y ocuparon 11.3 (DE = 2.3) horas/día en tiempo sedentario (TS). El índice de masa corporal promedio fue 29.4 (DE = 4.0) kg/m2 y el porcentaje de grasa corporal fue 35.4 (DE = 5.6) %. La mayoría (75%) no pudo definir qué es un programa de rehabilitación cardiaca, 88.9% nunca ha participado en uno y 50% reportó que su AF y tiempo de ejercicio se redujo durante la pandemia por COVID-19. Estas características sugieren un alto riesgo de mayores complicaciones cardiovasculares y mortalidad prematura. Programas que eduquen y promuevan la sustitución de TS por AF de cualquier intensidad podrían ayudar a mejorar la composición corporal y salud general en esta población.