Order reductions of Lorentz-Dirac-like equations

We discuss the phenomenon of preacceleration in the light of a method of successive approximations used to construct the physical order reduction of a large class of singular equations. A simple but illustrative physical example is analyzed to get more insight into the convergence properties of the method.Comment: 6 pages, LaTeX, IOP macros, no figure

Correlation between preoperative CT scan and lung metastases according to surgical approach in patients with colorectal cancer

Introduction: The number of lung metastases (M1) of colorectal carcinoma (CRC) in relation to the findings of computed tomography (CT) is the object of study. Methods: Prospective and multicenter study of the Spanish Group for Surgery of CRC lung metastases (GECMP-CCR). The role of CT in the detection of pulmonary M1 is evaluated in 522 patients who underwent a pulmonary metastasectomy for CRC. We define M1/CT as the ratio between metastatic nodules and those found on preoperative CT. Disease-specific survival (DSS), disease-free survival (DFS), and surgical approach were analyzed using the Kaplan–Meier method. Results: 93 patients were performed by video-assisted surgery (VATS) and 429 by thoracotomy. In 90%, the M1/CT ratio was =1, with no differences between VATS and thoracotomy (94.1% vs 89.7%, p = 0.874). In the remaining 10% there were more M1s than those predicted by CT (M1/CT > 1), with no differences between approaches (8.6% vs 10%, p = 0.874). 51 patients with M1/CT > 1, showed a lower median DSS (35.4 months vs 55.8; p = 0.002) and DFS (14.2 months vs 29.3; p = 0.025) compared to 470 with M1/CT = 1. No differences were observed in DSS and DFS according to VATS or thoracotomy. Conclusions: Our study shows equivalent oncological results in the resection of M1 of CRC using VATS or thoracotomy approach. The group of patients with an M1/CT ratio >1 have a worse DSS and DFS, which may mean a more advanced disease than predicted preoperatively. Introducción El número de metástasis pulmonares (M1) de carcinoma colorrectal (CCR) en relación con los hallazgos de la tomografía computarizada (TC), es objeto de estudio. Métodos Estudio prospectivo y multicéntrico del Grupo Español de Cirugía de las metástasis pulmonares del CCR (GCMP-CCR). Se evalúa el papel de la TC en la detección de M1 pulmonares en 522 pacientes intervenidos de una metastasectomía pulmonar por CCR. Definimos como M1/CT al cociente entre los nódulos metastásicos y los hallados en la TC preoperatoria. Se analizó la supervivencia específica de enfermedad (SEE), la supervivencia libre de enfermedad (SLE) y el abordaje quirúrgico mediante el método de Kaplan-Meier. Resultados En 93 pacientes se utilizó la cirugía videoasistida (VATS) y 429 toracotomías. En un 90% el cociente M1/TC fue =1, sin diferencias entre VATS y toracotomía (94,1 vs. 89,7%; p = 0,874). En el 10% restante existían más M1 que las predichas por la TC (M1/CT > 1), sin diferencias entre abordajes (8,6 vs. 10%; p = 0,874). Cincuenta y un pacientes con M1/CT > 1, mostraron una menor mediana de SEE (35,4 vs. 55,8 meses; p = 0,002) y SLE (14,2 vs. 29,3 meses; p = 0,025) en comparación con 470 con M1/CT = 1. No se observaron diferencias en la SEE y la SLE según VATS o toracotomía. Conclusiones Nuestro estudio muestra unos resultados oncológicos equivalentes en la resección de M1 de CCR mediante abordaje VATS o toracotomía. El grupo de pacientes con un cociente M1/CT > 1 presentan una peor SEE y SLE, pudiendo significar una enfermedad más avanzada de la predicha preoperatoriamente

TET2 overexpression in chronic lymphocytic leukemia is unrelated to the presence of TET2 variations

This is an open access article distributed under the Creative Commons Attribution License.TET2 is involved in a variety of hematopoietic malignancies, mainly in myeloid malignancies. Most mutations of TET2 have been identified in myeloid disorders, but some have also recently been described in mature lymphoid neoplasms. In contrast to the large amount of data about mutations of TET2, some data are available for gene expression. Moreover, the role of TET2 in chronic lymphocytic leukemia (CLL) is unknown. This study analyzes both TET2 expression and mutations in 48 CLL patients. TET2 expression was analyzed by exon arrays and quantitative real-time polymerase chain reaction (qRT-PCR). Next-generation sequencing (NGS) technology was applied to investigate the presence of TET2 variations. Overexpression of TET2 was observed in B-cell lymphocytes from CLL patients compared with healthy donors (P = 0.004). In addition, in CLL patients, an overexpression of TET2 was also observed in the clonal B cells compared with the nontumoral cells (P = 0.002). However, no novel mutations were observed. Therefore, overexpression of TET2 in CLL seems to be unrelated to the presence of genomic TET2 variations.This work was partially supported by Grants from the Spanish Fondo de Investigaciones Sanitarias FIS 09/01543, PI12/00281, Proyectos de Investigacion del SACYL 355/A/09, COST Action “EuGESMA” (BM0801), Fundación “Manuel Solorzano,” Obra Social Banca Cívica (Caja Burgos), Fundacion Española de Hematología y Hemoterapia (FEHH), and by a Grant (RD12/0036/0069) from Red Temática de Investigación Cooperativa en Cáncer (RTICC), Instituto de Salud Carlos III (ISCIII), Spanish Ministry of Economy and Competitiveness and European Regional Development Fund (ERDF) “Una manera de hacer Europa”, and NGS-PTL no. 306242. Maríıa Hernandez-Sánchez is fully suported by an “Ayuda predoctoral de la Junta de Castilla y Leon” by the “Fondo Social Europeo.”Peer Reviewe

Positive Influence Of A Dental Anaesthesia Simulation Model On The Perception Of Learning By Mexican Dental Students

Introduction: This study evaluated the influence of 3-repetition training with a dental anesthesia simulation model (DASM) on the perception of learning by dental students. Materials and methods: Dental students who had never used a dental anesthesia technique were randomly divided into 2 groups that were taught the anterior superior alveolar nerve infiltrative anesthesia technique. Group 1 (G1, N=10) followed a 3-stage learning method: 1st) theoretical lecture, 2nd) clinical demonstration, and 3rd) DASM training, including 3 repetitions of the anesthesia technique. Group 2 (G2, N=10) followed only the 1st and 2nd stages. The students in both groups then performed the anesthesia technique. The perception of the students was evaluated by 4 learning concepts. Each was evaluated with a 5-point Likert Scale questionnaire. The average score of each item of the questionnaire for G1 was compared with that of G2. Statistically significant differences were identified with the Mann-Whitney test. The average working time of each group was timed and compared by Student’s t-test to identify possible statistically significant differences. Results: Students in G1 showed higher average scores of perception in controlling the handling of the dental syringe and confidence in performing the injection (p\u3c0.05), and showed an average working time shorter than that of the students in G2 (p\u3c0.05). Conclusion: The DASM positively influenced the perception learning of the dental students; it increased their confidence and syringe handling ability, as well as skills to perform the injection of anesthesia more quickly

Tomographic findings and mortality in patients with severe and critical pneumonia with COVID-19 diagnosis

Introduction: A high percentage of patients with non-severe (17.9%) and severe (2.9%) atypical pneumonia do not display pulmonary tomographic findings upon hospital admission; furthermore, lesion associated with COVI-19 are peripherally distributed in a multifocal ground-glass pattern, as well as displaying an irregular consolidation pattern, with a posterior or lower lobe predilection. The main objective of this study was to identify the pulmonary radiological patterns in patients diagnosed with SARS-CoV-2 pneumonia, the factors associated with the need for mechanical ventilation, as well as their survival rates at 30 days. Methods: We report the pulmonary tomographic findings of 490 consecutive patients with severe and critical pneumonia due to SARS-CoV-2. The patients were classified according to the tomography and demographic findings, sepsis severity prognostic scales, Charlson comorbidity index (CCI), the Sequential Organ Failure Assessment (SOFA), and the Acute Physiology and Chronic Health Evaluation (APACHE IV). The Kaplan-Meier method was used to calculate survival distributions. Results: 89.80% of patients had ground-glass opacities, 81.63% radiologic consolidation sign, 42.45% vascular thickening pattern, 37.55% lymphadenopathies, 14.90% pleural effusion, and 2.65% pulmonary thrombosis; meanwhile, 91.02% had bilateral lesions, 85.51% had peripheral lesions, and 75.92% had basal lobe lesions. APACHE IV (HR, 1.191, 95% CI [1.126, 1.260]), SOFA (HR, 5.178, 95%CI [3.103, 8.641]), and CCI (HR, 0.673, 95%CI [0.510, 0.889]), as well as the pulmonary damage severity index (HR, 1.282, 95%CI [1.151, 1.428]), predict the need for invasive mechanical ventilation. Only moderate ARDS patients with mild and severe lung disease showed different 30-day mortality distributions (χ2 = 7.00, p = 0.008). Discussion: Although the survival distributions did not vary significantly, an overwhelming majority of patients (i.e., 84.35%) with a higher pulmonary damage severity index (i.e., 23>) died within 30 days of hospital admission, while only 25.91% with moderate lung damage and 2.42% with mild lung damage

Two novel variants of the ABCG5 gene cause xanthelasmas and macrothrombocytopenia: a brief review of hematologic abnormalities of sitosterolemia

[EN] Background: Sitosterolemia (STSL) is a recessive inherited disorder caused by pathogenic variants in the ABCG5 and ABCG8 genes. Increased levels of plasma plant sterols (PSs) usually result in xanthomas and premature coronary atherosclerosis, although hematologic abnormalities may occasionally be present. This clinical picture is unfamiliar to many physicians, and patients may be at high risk of misdiagnosis. Objectives: To report two novel ABCG5 variants causing STSL in a Spanish patient, and review the clinical and mutational landscape of STSL. Patient/Methods: A 46-year-old female was referred to us with lifelong macrothrombocytopenia. She showed familial hypercholesterolemia-related xanthomas. Molecular analysis was performed with high-throughput sequencing. Plasma PS levels were evaluated with gas–liquid chromatography. The STSL landscape was reviewed with respect to specific online databases and all reports published since 1974. Results: A blood smear revealed giant platelets and stomatocytes. Novel compound heterozygous variants were detected in exons 7 (c.914C>G) and 13 (c.1890delT) of ABCG5. The patient showed an increased plasma level of sitosterol. These findings support the diagnosis of STSL. In our review, we identified only 25 unrelated STLS patients who presented with hematologic abnormalities including macrothrombocytopenia

Genome-wide profiling of methylation identifies novel targets with aberrant hyper-methylation and reduced expression in low-risk myelodysplastic syndromes

Gene expression profiling signatures may be used to classify the subtypes of Myelodysplastic syndrome (MDS) patients. However, there are few reports on the global methylation status in MDS. The integration of genome-wide epigenetic regulatory marks with gene expression levels would provide additional information regarding the biological differences between MDS and healthy controls. Gene expression and methylation status were measured using high-density microarrays. A total of 552 differentially methylated CpG loci were identified as being present in low-risk MDS; hypermethylated genes were more frequent than hypomethylated genes. In addition, mRNA expression profiling identified 1005 genes that significantly differed between low-risk MDS and the control group. Integrative analysis of the epigenetic and expression profiles revealed that 66.7% of the hypermethylated genes were underexpressed in low-risk MDS cases. Gene network analysis revealed molecular mechanisms associated with the low-risk MDS group, including altered apoptosis pathways. The two key apoptotic genes BCL2 and ETS1 were identified as silenced genes. In addition, the immune response and micro RNA biogenesis were affected by the hypermethylation and underexpression of IL27RA and DICER1. Our integrative analysis revealed that aberrant epigenetic regulation is a hallmark of low-risk MDS patients and could have a central role in these diseases. © 2013 Macmillan Publishers Limited All rights reserved

An oleuropein β-glucosidase from olive fruit is involved in determining the phenolic composition of virgin olive oil

Phenolic composition of virgin olive oil is determined by the enzymatic and/or chemical reactions that take place during olive fruit processing. Of these enzymes, β-glucosidase activity plays a relevant role in the transformation of the phenolic glycosides present in the olive fruit, generating different secoiridoid derivatives. The main goal of the present study was to characterize olive fruit β-glucosidase genes and enzymes responsible for the phenolic composition of virgin olive oil. To achieve that, we have isolated an olive β-glucosidase gene from cultivar Picual (OepGLU), expressed in Nicotiana benthamiana leaves and purified its corresponding recombinant enzyme. Western blot analysis showed that recombinant OepGLU protein is detected by an antibody raised against the purified native olive mesocarp β-glucosidase enzyme, and exhibits a deduced molecular mass of 65.0 kDa. The recombinant OepGLU enzyme showed activity on the major olive phenolic glycosides, with the highest levels with respect to oleuropein, followed by ligstroside and demethyloleuropein. In addition, expression analysis showed that olive GLU transcript level in olive fruit is spatially and temporally regulated in a cultivar-dependent manner. Furthermore, temperature, light and water regime regulate olive GLU gene expression in olive fruit mesocarp. All these data are consistent with the involvement of OepGLU enzyme in the formation of the major phenolic compounds present in virgin olive oil