RESUMEN

Background: Recurrent genetic alterations contributing to leukemogenesis have been identified in pediatric B-cell Acute Lymphoblastic Leukemia (B-ALL), and some are useful for refining classification, prognosis, and treatment selection. IKZF1plus is a complex biomarker associated with a poor prognosis. It is characterized by IKZF1 deletion coexisting with PAX5, CDKN2A/2B, or PAR1 region deletions. The mutational spectrum and clinical impact of these alterations have scarcely been explored in Mexican pediatric patients with B-ALL. Here, we report the frequency of the IKZF1plus profile and the mutational spectrum of IKZF1, PAX5, CDKN2A/2B, and ERG genes and evaluate their impact on overall survival (OS) in a group of patients with B-ALL. Methods: A total of 206 pediatric patients with de novo B-ALL were included. DNA was obtained from bone marrow samples at diagnosis before treatment initiation. A custom-designed next-generation sequencing panel was used for mutational analysis. Kaplan-Meier analysis was used for OS estimation. Results: We identified the IKZF1plus profile in 21.8% of patients, which was higher than that previously reported in other studies. A significantly older age (p=0.04), a trend toward high-risk stratification (p=0.06), and a decrease in 5-year Overall Survival (OS) (p=0.009) were observed, although heterogeneous treatment protocols in our cohort would have impacted OS. A mutation frequency higher than that reported was found for IKZF1 (35.9%) and CDKN2A/2B (35.9%) but lower for PAX5 (26.6%). IKZF1MUT group was older at diagnosis (p=0.0002), and most of them were classified as high-risk (73.8%, p=0.02), while patients with CDKN2A/2BMUT had a higher leukocyte count (p=0.01) and a tendency toward a higher percentage of blasts (98.6%, >50% blasts, p=0.05) than the non-mutated patients. A decrease in OS was found in IKZF1MUT and CDKN2A/2BMUT patients, but the significance was lost after IKZF1plus was removed. Discussion: Our findings demonstrated that Mexican patients with B-ALL have a higher prevalence of genetic markers associated with poor outcomes. Incorporating genomic methodologies into the diagnostic process, a significant unmet need in low- and mid-income countries, will allow a comprehensive identification of relevant alterations, improving disease classification, treatment selection, and the general outcome.

RESUMEN

As a part of the mission to create materials that are more environmentally friendly, we present the following proposal, in which a study of the mechanical properties of composite materials comprising a polyester resin with sisal fiber and bentonite particles was conducted. Sisal fiber was added to a matrix in percentages ranging from 5% to 45% in relation to the polyester resin weight, while bentonite remained fixed at 7% in relation to the polyester resin weight. The specimens were manufactured by compression molding. The mechanical properties were analyzed by tensile, bending, impact, stepped creep, and relaxation tests. In addition, energy-dispersive X-ray spectroscopy and scanning electron microscopy analyses were carried out to analyze the composition and heterogeneity of the structure of the composite material. The results obtained showed that 7% of bentonite added to the matrix affects the tensile strength. Flexural strength increased by up to 21% in the specimens with a 20% addition of sisal fiber, while the elastic modulus increased by up to 43% in the case of a 20% addition of sisal fiber. The viscoelastic behavior was improved, while the relaxation stress was affected.

RESUMEN

OBJECTIVE: To identify the type of infections and risk factors for infection-related mortality (IRM) after allogeneic hematopoietic stem cell transplantation (HSCT). METHODS: Retrospective cohort study of patients <16 years of age treated in 2010-2019 was conducted. Unadjusted hazard ratios (HR) and adjusted hazard ratios (aHR) with 95% confidence intervals (95% CIs) were estimated using Cox regression. Cumulative incidence was calculated. RESULTS: Data for 99 pediatric patients were analyzed. The myeloablative conditioning was the most used regimen (78.8%) and the hematopoietic stem cell source was predominantly peripheral blood (80.8%). Primary graft failure occurred in 19.2% of patients. Frequency of acute graft-versus-host disease was 46.5%. Total of 136 infectious events was recorded, the most common of which were bacterial (76.4%) followed by viral infection (15.5%) and then fungal infection (8.1%). The best predictors for infection subtypes where the following: a) for bacterial infection (the age groups of 10.1-15 years: aHR = 3.33; 95% CI: 1.62-6.85 and. >15 years: aHR = 3.34; 95% CI: 1.18-9.45); b) for viral infection (graft versus host disease: aHR = 5.36; 95% CI: 1.62-17.68), however, for fungal infection statistically significant predictors were not identified. Related mortality was 30% (n = 12). Increased risk for infection-related mortality was observed in patients with unrelated donor and umbilical cord stem cells recipients (HR = 3.12; 95% CI: 1.00-9.85). CONCLUSIONS: Frequencies of infections and infection-related mortality appear to be similar to those reported. Unrelated donors and stem cells from umbilical cord recipients were associated with a high risk of mortality.

Asunto(s)

RESUMEN

The influence of the addition of bentonite nanoparticles on the tensile and flexural strength of a thermosetting polymer matrix composite material reinforced with hemp fibers was de-terminated. All composites were manufactured with 5% of bentonite in the polymer mass-weight ratios and 10 to 45 wt% of fibers with a step of 5%. For mechanical characterization, tensile and flexural tests were performed: scanning electron microscopy and energy-dispersive X-ray spectroscopy analyses were carried out. The tensile strength of the samples containing bentonite compared to the polymer samples with the fiber addition was affected for all fiber addition percentages, except for 35% while the flexural resistance improved with the addition of bentonite in the percentages of 20, 30, 35, and 45% of fiber addition. With the addition of bentonite, the maximum values of tensile and flexural strength were both obtained for the 35% addition of fibers, with values of 34.28 MPa and 98.04 MPa, respectively. The presence of bentonite favored the rigidity of the material to traction and bending, which was reflected through an increase in the elastic modulus compared to the composite that only had fiber. The maximum values obtained were 9065 MPa in tension and 8453 MPa in flexion for the 40% and 35% of addition of fiber, respectively. Microscopy showed a good distribution of fibers in the matrix, the absence of internal porosities, and a good interaction between matrix and reinforcement.

RESUMEN

In the present work, parameters for adapting the behavior of the uniaxial three-element viscoelastic constitutive model with integer and fractional index derivatives to the mechanical evolution of an epoxy-composite material reinforced with long random henequen fibers, were determined. Cyclic loading-unloading with 0.1%, 0.2%, 0.3%, …, 1.0% controlled strain and staggered fluency experiments at 5 MPa, 10 MPa, and 15 MPa constant tension were performed in stages, and the obtained data were used to determine and validate the model's parameter values. The Inverse Method of Identification was used to calculate the parameters, and the Particle Swarm Optimization (PSO) method was employed to achieve minimization of the error function. A comparison between the simulated uniaxial results and the experimental data is demonstrated graphically. There exists a strong dependence between properties of the composite and the fiber content (0 wt%, 9 wt%, 14 wt%, 22 wt%, and 28 wt% weight percentage fiber/matrix), and therefore also of the model parameter values. Both uniaxial models follow the viscoelastic behavior of the material and the fractional index version presents the best accuracy. The latter method was noted to be adequate for determination of the aforementioned constants using non-large experimental data and procedures that are easy to implement.

RESUMEN

RESUMEN La tuberculosis cutánea es una presentación rara de la infección por Mycobacterium tuberculosis. Se presenta el caso de una mujer sin antecedentes médicos de importancia, con un tiempo de enfermedad de año y medio, caracterizado por lesiones tipo esporotricoide, con diseminación linfocutánea en miembro superior derecho, de evolución lentamente progresiva. Se realizó un estudio histopatológico encontrándose células gigantes tipo Langhans y escasa necrosis. El paciente recibió terapia de esquema sensible antituberculoso, con evolución favorable.

ABSTRACT Cutaneous tuberculosis is a rare presentation of Mycobacterium tuberculosis infection. We present the case of a woman without important medical history, with a disease period of one year and a half, characterized by sporotrichoid-like lesions, with lymphocutaneous dissemination in the right upper limb, and with slowly progressive evolution. The histopathological tests revealed Langhans type giant cells and scarce necrosis. The patient received therapy with a sensitive antituberculous scheme, and evolved favorably.

Asunto(s)

RESUMEN

BACKGROUND AND OBJECTIVES: Past history of stroke has been associated with an increased risk of a new ischemic stroke. Several studies have indicated increased prevalence of strokes among coronavirus patients. However, the role of past history of stroke in COVID19 patients is still unclear. The purpose of this systematic review is to evaluate and summarize the level of evidence on past history of stroke in COVID19 patients. METHODS: A systematic review was performed according to the PRISMA guidelines was performed in PubMed, Embase, EBSCO Host, Scopus, Science Direct, Medline, and LILACS. Eligibility criteria: We evaluated studies including patients with diagnosis of COVID 19 and a past history of stroke. Risk of bias: was evaluated with the Newcastle- Ottawa Scale (NOS) and experimental studies were evaluated using the ROBINS-I scale. RESULTS: Seven articles out of the total 213 articles were evaluated and included, involving 3244 patients with SARS VOC 2 Disease (COVID19) of which 198 had a history of cerebrovascular disease. Meta-analysis of the data was performed, observing an increase in mortality in patients with a history of cerebrovascular disease compared to those with different comorbidities or those without underlying pathology (OR 2.78 95 % CI [1.42-5.46] p = 0.007; I2 = 49 %) showing adequate heterogeneity. The presence of publication bias was evaluated using the Egger test in a funnel plot, showing adequate. Asymmetry, indicating that there is no publication bias; however, due to the low number of included studies, we could not rule out or confirm the presence of bias. CONCLUSIONS: The history of cerebrovascular disease was associated with a 2.78-fold increased risk of mortality compared to patients with other comorbidities or without underlying pathologies.

Asunto(s)

RESUMEN

BACKGROUND: Musculoskeletal disorders (MSD) are important health problems in working populations. The study aimed to determine the prevalence of MSD among school teachers from urban and rural areas in Chuquisaca, Bolivia. METHODS: A cross-sectional study was conducted in 60 randomly selected schools. In total, 1062 teachers were invited to participate (response 58%). The Spanish version of the Standardized Nordic questionnaire was used assessing the 12-months and 7-days prevalence of MSD as well as the 12-months prevalence of work limiting pain. Prevalence were calculated for the different parts of the body; as summary measures, MSD in any part of the body and in ≥3 parts of the body were assessed. Crude and adjusted odds ratios with 95% confidence intervals were calculated using logistic regression models adjusting for age, sex, teaching level and school type. RESULTS: Prevalence of MSD in any part of the body was 86% during the last 12 months, 63% during the last 7 days and 15% for work limiting pain. MSD was most common in the neck (12-months prevalence 47%) and least common in the wrist/hands (26%). In the adjusted model, teachers working in rural areas presented significantly higher odds than teachers from urban schools for work-limiting pain during the last 12-months considering any part of the body (aOR 2.2; 95% CI 1.1-4.1), and for ≥3 parts of the body (aOR 3.7; 95% CI 1.3-10.6). CONCLUSION: The prevalence of MSD is high in School teachers, even more in teachers working in rural areas. It is needed to identify risk factors for MSD in teachers in order to propose appropriate strategies to control and reduce it.

Asunto(s)

RESUMEN

BACKGROUND: Regeneration of neurons and fibers in the mammalian spinal cord has not been plausible, even though extensive studies have been made to understand the restrictive factors involved. New experimental models and strategies are necessary to determine how new nerve cells are generated and how fibers regrow and connect with their targets in adult animals. Non-vertebrate deuterostomes might provide some answers to these questions. Echinoderms, with their amazing regenerative capacities could serve as model systems; however, very few studies have been done to study the regeneration of their nervous system. RESULTS: We have studied nerve cord regeneration in the echinoderm Holothuria glaberrima. These are sea cucumbers or holothurians members of the class Holothuroidea. One radial nerve cord, part of the echinoderm CNS, was completely transected using a scalpel blade. Animals were allowed to heal for up to four weeks (2, 6, 12, 20, and 28 days post-injury) before sacrificed. Tissues were sectioned in a cryostat and changes in the radial nerve cord were analyzed using classical dyes and immunohistochemistry. In addition, the temporal and spatial distribution of cell proliferation and apoptosis was assayed using BrdU incorporation and the TUNEL assay, respectively.We found that H. glaberrima can regenerate its radial nerve cord within a month following transection. The regenerated cord looks amazingly similar in overall morphology and cellular composition to the uninjured cord. The cellular events associated to radial cord regeneration include: (1) outgrowth of nerve fibers from the injured radial cord stumps, (2) intense cellular division in the cord stumps and in the regenerating radial nerve cords, (3) high levels of apoptosis in the RNC adjacent to the injury and within the regenerating cord and (4) an increase in the number of spherule-containing cells. These events are similar to those that occur in other body wall tissues during wound healing and during regeneration of the intestine. CONCLUSION: Our data indicate that holothurians are capable of rapid and complete regeneration of the main component of their CNS. Regeneration involves both the outgrowth of nerve fibers and the formation of neurons. Moreover, the cellular events employed during regeneration are similar to those involved in other regenerative processes, namely wound healing and intestinal regeneration. Thus, holothurians should be viewed as an alternative model where many of the questions regarding nervous system regeneration in deuterostomes could be answered.

Asunto(s)

RESUMEN

Semiologia neurologica, desarrollo y examen de las funciones cognoscitivas, examen de las funciones sensoriales, semiologia de la motricidad, semiologia de los pares craneales, semiologia de los nervios espinales, sindromes neurologicos, sindromes cognitivos, sindromes topograficos hemisfericos, sindromes sensitivos, sindromes motores, sindromes extrapiramidales, sindromes motores con compromiso cognitivo, sindromes de los pares craneanos, sindrome de los nervios perifericos, sindrome convulsivo epilepsia, sindrome de hipertension intra craneana HIC, sindrome meningeo, examenes complementarios en neurologia

Asunto(s)