El extracto acuoso de Phyllanthus orbicularis K protege al ADN plasmídico del daño inducido por las radiaciones ultravioletas

AGRADECIMIENTOS Agradecemos a la Dr. Rosalina Berazain por la autenticación de las especies Phyllanthus orbicularis K colectadas.Objetivo: Evaluar el efecto protector del extracto acuoso de Phyllanthus orbicularis, K ante el daño inducido por las radiaciones UVB y UVC. Material y métodos: Se empleó el ensayo con ADN plasmídico (pBluescript SK II) libre de célula. Se evaluó la capacidad del extracto acuoso de P. orbicularis de inducir roturas de cadenas en el plásmido, a las concentraciones 0,0001-2,0 mg/ml. Se realizaron estudios de protección del extracto frente a las radiaciones UVB y UVC a las concentraciones de 0,1-2,0 mg/ml. Se cuantificó la transmitancia del extracto frente ambos tipos de radiaciones. Resultados: Ninguna de las concentraciones evaluadas resultó genotóxica en 30 min de exposición. Las concentraciones ≥ 1 mg/ml de P. orbicularis sí indujeron roturas de cadenas a tiempos mayores de evaluación. El extracto de P. orbicularis protegió al ADN frente a las radiaciones UVB y UVC a concentraciones ≥ 0,1 mg/ml y 0,5 mg/ml respectivamente. Conclusiones: En nuestras condiciones experimentales, el extracto acuoso de P.orbicularis protege al ADN frente al daño inducido por las radiaciones UV.Aim: The aim of this work was to evaluate the protective effect of aqueous extract of Phyllanthus orbicularis, K from the damage induced by UV radiation. Material and methods: The plasmid-based non cellular system was used. The extract capacity to induce DNA strand breaks was evaluated at 0.0001- 2.0 mg/ml concentrations. The protective effect of extract against UVB and UVC radiation was evaluated at 0.1- 2.0 mg/ml concentrations. The transmittance of extract was measured for both UV radiations. Results: The P. orbicularis aqueous extract was not genotoxic even after 30 min of exposure. Concentrations ≥ 1 mg/ml of extract induced strand breaks at major times of exposition. P.orbicularis extract protected DNA against UVB and UVC radiation at concentrations ≥ 0.1 mg/ml and 0.5 mg/ml respectively. Conclusions: In our experimental conditions, P.orbicularis aqueous extract protects DNA from damage induced by UV radiation.Este trabajo fue realizado por el proyecto de colaboración internacional CAPES (Brasil)- MES (Cuba).El financiamiento y soporte fue brindado por CAPES (São Paulo, Brazil), FAPESP (São Paulo, Brazil) y CNPq (Brasília, Brazil)

Effect of hot calendering on physical properties and water vapor transfer resistance of bacterial cellulose films

This work investigates the effect of hot calendering on bacterial cellulose (BC) films properties, aiming the achievement of good transparency and barrier property. A comparison was made using vegetal cellulose (VC) films on a similar basis weight of around 40 g.m-2. The optical-structural, mechanical and barrier property of BC films were studied and compared with those of highly beaten VC films. The Youngs moduli and tensile index of the BC films are much higher than those obtained for VC (14.5 16.2 GPa vs 10.8 8.7 GPa and 146.7 64.8 N.m.g-1 vs 82.8 40.5 N.m.g-1), respectively. Calendering increased significantly the transparency of BC films from 53.0 % to 73.0 %. The effect of BC ozonation was also studied. Oxidation with ozone somewhat enhanced the brightness and transparency of the BC films, but at the expenses of slightly lower mechanical properties. BC films exhibited a low water vapor transfer rate, when compared to VC films and this property decreased by around 70 % following calendering, for all films tested. These results show that calendering could be used as a process to obtain films suitable for food packaging applications, where transparency, good mechanical performance and barrier properties are important. The BC films obtained herein are valuable products that could be a good alternative to the highly used plastics in this industry.The authors thank FCT (Fundação para a Ciência e Tecnologia) and FEDER (Fundo Europeu de Desenvolvimento Regional) for the financial support of the project FCT PTDC/AGR-FOR/3090/2012— FCOMP-01-0124-FEDER-027948 and the awarding of a research grant for Vera Costa

T cells, more than antibodies, may prevent symptoms developing from respiratory syncytial virus infections in older adults.

INTRODUCTION: The immune mechanisms supporting partial protection from reinfection and disease by the respiratory syncytial virus (RSV) have not been fully characterized. In older adults, symptoms are typically mild but can be serious in patients with comorbidities when the infection extends to the lower respiratory tract. METHODS: This study formed part of the RESCEU older-adults prospective-cohort study in Northern Europe (2017-2019; NCT03621930) in which a thousand participants were followed over an RSV season. Peripheral-blood samples (taken pre-season, post-season, during illness and convalescence) were analyzed from participants who (i) had a symptomatic acute respiratory tract infection by RSV (RSV-ARTI; N=35) or (ii) asymptomatic RSV infection (RSV-Asymptomatic; N=16). These analyses included evaluations of antibody (Fc-mediated-) functional features and cell-mediated immunity, in which univariate and machine-learning (ML) models were used to explore differences between groups. RESULTS: Pre-RSV-season peripheral-blood biomarkers were predictive of symptomatic RSV infection. T-cell data were more predictive than functional antibody data (area under receiver operating characteristic curve [AUROC] for the models were 99% and 76%, respectively). The pre-RSV season T-cell phenotypes which were selected by the ML modelling and which were more frequent in RSV-Asymptomatic group than in the RSV-ARTI group, coincided with prominent phenotypes identified during convalescence from RSV-ARTI (e.g., IFN-γ+, TNF-α+ and CD40L+ for CD4+, and IFN-γ+ and 4-1BB+ for CD8+). CONCLUSION: The evaluation and statistical modelling of numerous immunological parameters over the RSV season suggests a primary role of cellular immunity in preventing symptomatic RSV infections in older adults

Electroporation-Induced Electrosensitization

BACKGROUND: Electroporation is a method of disrupting the integrity of cell membrane by electric pulses (EPs). Electrical modeling is widely employed to explain and study electroporation, but even most advanced models show limited predictive power. No studies have accounted for the biological consequences of electroporation as a factor that alters the cell's susceptibility to forthcoming EPs. METHODOLOGY/PRINCIPAL FINDINGS: We focused first on the role of EP rate for membrane permeabilization and lethal effects in mammalian cells. The rate was varied from 0.001 to 2,000 Hz while keeping other parameters constant (2 to 3,750 pulses of 60-ns to 9-µs duration, 1.8 to 13.3 kV/cm). The efficiency of all EP treatments was minimal at high rates and started to increase gradually when the rate decreased below a certain value. Although this value ranged widely (0.1-500 Hz), it always corresponded to the overall treatment duration near 10 s. We further found that longer exposures were more efficient irrespective of the EP rate, and that splitting a high-rate EP train in two fractions with 1-5 min delay enhanced the effects severalfold. CONCLUSIONS/SIGNIFICANCE: For varied experimental conditions, EPs triggered a delayed and gradual sensitization to EPs. When a portion of a multi-pulse exposure was delivered to already sensitized cells, the overall effect markedly increased. Because of the sensitization, the lethality in EP-treated cells could be increased from 0 to 90% simply by increasing the exposure duration, or the exposure dose could be reduced twofold without reducing the effect. Many applications of electroporation can benefit from accounting for sensitization, by organizing the exposure either to maximize sensitization (e.g., for sterilization) or, for other applications, to completely or partially avoid it. In particular, harmful side effects of electroporation-based therapies (electrochemotherapy, gene therapies, tumor ablation) include convulsions, pain, heart fibrillation, and thermal damage. Sensitization can potentially be employed to reduce these side effects while preserving or increasing therapeutic efficiency

Burden of respiratory syncytial virus infection in community-dwelling older adults in Europe (RESCEU): An international prospective cohort study

Background: Respiratory syncytial virus (RSV) infection in older adults is recognised as an important health issue. We aimed to assess the community burden of RSV in Europe in older adults aged >60 years. Methods: This international, prospective, observational cohort study is part of work by the REspiratory Syncytial virus Consortium in EUrope (RESCEU). Participants were recruited through general practitioners’ (GPs) offices before two independent RSV seasons. Participants reported weekly about symptoms of acute respiratory tract infection (ARTI) during one RSV season. ARTI patients were tested for RSV during home visits and completed a daily symptom diary. RSV illness included PCR-confirmed ARTI and those showing seroconversion over the season. RSV ARTI was based on PCR alone (ClinicalTrials.gov, NCT03621930). Results: We recruited 1040 participants (527 in season 2017–2018 and 513 in season 2018–2019) with a median age of 75 years (range 60–100 years). Of these, 1023 (99%) lived independently at home at baseline. RSV illness incidence was 22 out of 527 (4.2%) and 37 out of 513 (7.2%) in the respective seasons. RSV illness did not affect frailty or cardiopulmonary status during the course of the study. No patients were hospitalised or died from RSV illness. In the 36 patients with PCR confirmed RSV ARTI, symptom duration averaged 19 days, while a doctor’s visit took place in 11 out of 36 cases (31%). RSV ARTI could not be differentiated clinically from all other ARTIs based on symptoms. Conclusion: This European study showed that RSV is prevalent in community-dwelling older adults and rarely causes severe disease. This suggests that watchful waiting, using a continuity of care approach to identify those who do need more intensive care, is often justified when RSV is suspected in family practice