Dengue viruses and promising envelope protein domain III-based vaccines

Abstract Dengue viruses are emerging mosquito-borne pathogens belonging to Flaviviridae family which are transmitted to humans via the bites of infected mosquitoes Aedes aegypti and Aedes albopictus. Because of the wide distribution of these mosquito vectors, more than 2.5 billion people are approximately at risk of dengue infection. Dengue viruses cause dengue fever and severe life-threatening illnesses as well as dengue hemorrhagic fever and dengue shock syndrome. All four serotypes of dengue virus can cause dengue diseases, but the manifestations are nearly different depending on type of the virus in consequent infections. Infection by any serotype creates life-long immunity against the corresponding serotype and temporary immunity to the others. This transient immunity declines after a while (6 months to 2 years) and is not protective against other serotypes, even may enhance the severity of a secondary heterotypic infection with a different serotype through a phenomenon known as antibody-depended enhancement (ADE). Although, it can be one of the possible explanations for more severe dengue diseases in individuals infected with a different serotype after primary infection. The envelope protein (E protein) of dengue virus is responsible for a wide range of biological activities, including binding to host cell receptors and fusion to and entry into host cells. The E protein, and especially its domain III (EDIII), stimulates host immunity responses by inducing protective and neutralizing antibodies. Therefore, the dengue E protein is an important antigen for vaccine development and diagnostic purposes. Here, we have provided a comprehensive review of dengue disease, vaccine design challenges, and various approaches in dengue vaccine development with emphasizing on newly developed envelope domain III-based dengue vaccine candidates. Keywords: Dengue virus Envelope protein Chimeric vaccine Disease Immunogenicit

Nanoparticle-induced neuronal toxicity across placental barriers is mediated by autophagy and dependent on astrocytes

The potential for maternal nanoparticle (NP) exposures to cause developmental toxicity in the fetus without the direct passage of NPs has previously been shown, but the mechanism remained elusive. We now demonstrate that exposure of cobalt and chromium NPs to BeWo cell barriers, an in vitro model of the human placenta, triggers impairment of the autophagic flux and release of interleukin-6. This contributes to the altered differentiation of human neural progenitor cells and DNA damage in the derived neurons and astrocytes. Crucially, neuronal DNA damage is mediated by astrocytes. Inhibiting the autophagic degradation in the BeWo barrier by overexpression of the dominant-negative human ATG4BC74A significantly reduces the levels of DNA damage in astrocytes. In vivo, indirect NP toxicity in mice results in neurodevelopmental abnormalities with reactive astrogliosis and increased DNA damage in the fetal hippocampus. Our results demonstrate the potential importance of autophagy to elicit NP toxicity and the risk of indirect developmental neurotoxicity after maternal NP exposure

An explanatory study on the concept of nursing presence from the perspective of patients admitted to hospitals

Aims and objectives: To clarify the concept of nursing presence through patients� perception. Background: The holistic caring process at the bedside must incorporate the concept of nursing presence. Most of the research about nursing presence is based on nurses� experiences, and research into patients� experiences is minimal. According to goals of patient centredness, the association between the patient satisfaction and nursing presence, and patients� ability to understand this concept, it is important to explore this concept from the patients� perspective. Design: A qualitative approach. Methods: Based on purposive sampling technique, 12 patients were recruited. After participant observation, 15 interviews were carried out with participants. Data were transcribed verbatim and analysed using conventional qualitative content analysis. Results: Five main categories were drawn from the data including informed concentration, task-centred/patient-centred relationship, clarification of meanings, comprehensive participation and accountable encounter. Data analysis alongside the authors� reflections resulted in the emergence of one overarching theme, �coconstructed interaction�, which shows the notion that effective nurse�patient interaction enhances cooperation, coordination and collaboration in caring and improves nursing outcomes. Conclusions: Accordingly, the nursing presence would be ideal for patient-centred caring. Relevance to clinical practice: Knowing the perspectives of patients is important as the evaluation of nursing care quality should rely on outcome indicators that are sensitive to patients. For instance, client satisfaction and health status acceptance, especially as it relates to coping, comfort level, hope, and participation in decision-making, are included in the nursing outcomes� classification system. Thus, the findings of this study may facilitate improvement in the quality of care by continuous improvement in knowledge, attitudes and abilities of nurses. It is therefore recommended that managers and clinical nurses, by relying on these findings, design the caring activities so that nurses� presence can act as a facilitating factor for improving quality assurance. © 2017 John Wiley & Sons Lt