123 research outputs found
The effect of deworming on growth in one-year-old children living in a soil-transmitted helminth-endemic area of Peru: a randomized controlled trial
BACKGROUND:Appropriate health and nutrition interventions to prevent long-term adverse effects in children are necessary before two years of age. One such intervention may include population-based deworming, recommended as of 12 months of age by the World Health Organization in soil-transmitted helminth (STH)-endemic areas; however, the benefit of deworming has been understudied in early preschool-age children. METHODOLOGY/PRINCIPAL FINDINGS:A randomized, double-blind, placebo-controlled trial was conducted to determine the effect of deworming (500 mg single-dose crushed mebendazole tablet) on growth in one-year-old children in Iquitos, Peru. Children were enrolled during their routine 12-month growth and development clinic visit and followed up at their 18 and 24-month visits. Children were randomly allocated to: Group 1: deworming at 12 months and placebo at 18 months; Group 2: placebo at 12 months and deworming at 18 months; Group 3: deworming at both 12 and 18 months; or Group 4: placebo at both 12 and 18 months (i.e. control group). The primary outcome was weight gain at the 24-month visit. An intention-to-treat approach was used. A total of 1760 children were enrolled between September 2011 and June 2012. Follow-up of 1563 children (88.8%) was completed by July 2013. STH infection was of low prevalence and predominantly light intensity in the study population. All groups gained between 1.93 and 2.05 kg on average over 12 months; the average difference in weight gain (kg) compared to placebo was: 0.05 (95% CI: -0.05, 0.17) in Group 1; -0.07 (95%CI: -0.17, 0.04) in Group 2; and 0.04 (95%CI: -0.06, 0.14) in Group 3. There was no statistically significant difference in weight gain in any of the deworming intervention groups compared to the control group. CONCLUSIONS:Overall, with one year of follow-up, no effect of deworming on growth could be detected in this population of preschool-age children. Low baseline STH prevalence and intensity and/or access to deworming drugs outside of the trial may have diluted the potential effect of the intervention. Additional research is required to overcome these challenges and to contribute to strengthening the evidence base on deworming. TRIAL REGISTRATION:ClinicalTrials.gov (NCT01314937)
Studying nanotoxic effects of CdTe quantum dots in Trypanosoma cruzi
Semiconductor nanoparticles, such as quantum dots (QDs), were used to carry out experiments in vivo and ex vivo with Trypanosoma cruzi. However, questions have been raised regarding the nanotoxicity of QDs in living cells, microorganisms, tissues and whole animals. The objective of this paper was to conduct a QD nanotoxicity study on living T. cruzi protozoa using analytical methods. This was accomplished using in vitro experiments to test the interference of the QDs on parasite development, morphology and viability. Our results show that after 72 h, a 200 μM cadmium telluride (CdTe) QD solution induced important morphological alterations in T. cruzi, such as DNA damage, plasma membrane blebbing and mitochondrial swelling. Flow cytometry assays showed no damage to the plasma membrane when incubated with 200 μM CdTe QDs for up to 72 h (propidium iodide cells), giving no evidence of classical necrosis. Parasites incubated with 2 μM CdTe QDs still proliferated after seven days. In summary, a low concentration of CdTe QDs (2 μM) is optimal for bioimaging, whereas a high concentration (200 μM CdTe) could be toxic to cells. Taken together, our data indicate that 2 μM QD can be used for the successful long-term study of the parasite-vector interaction in real time
Lysine-based surfactants in nanovesicle formulations: the role of cationic charge position and hydrophobicity in in vitro cytotoxicity and intracellular delivery
Understanding nanomaterial interactions within cells is of increasing importance for assessing their toxicity and cellular transport. Here, we developed nanovesicles containing bioactive cationic lysine-based amphiphiles, and assessed whether these cationic compounds increase the likelihood of intracellular delivery and modulate toxicity. We found different cytotoxic responses among the formulations, depending on surfactant, cell line and endpoint assayed. The induction of mitochondrial dysfunction, oxidative stress and apoptosis were the general mechanisms underlying cytotoxicity. Fluorescence microscopy analysis demonstrated that nanovesicles were internalized by HeLa cells, and evidenced that their ability to release endocytosed materials into cell cytoplasm depends on the structural parameters of amphiphiles. The cationic charge position and hydrophobicity of surfactants determine the nanovesicle interactions within the cell and, thus, the resulting toxicity and intracellular behavior after cell uptake of the nanomaterial. The insights into some toxicity mechanisms of these new nanomaterials contribute to reducing the uncertainty surrounding their potential health hazards
Health-related quality of life after vertebral or hip fracture: a seven-year follow-up study
<p>Abstract</p> <p>Background</p> <p>The negative impact of vertebral and hip low-energy fractures on health-related quality-of-life (HRQOL) has been demonstrated previously, but few prospective long-term follow-up studies have been conducted. This study aims to (i) investigate the changes and long-term impact of vertebral or hip fracture and between fracture groups on HRQOL in postmenopausal women prospectively between two and seven years after the inclusion fracture, (ii) compare HRQOL results between fracture and reference groups and (iii) study the relationship between HRQOL and physical performance, spinal deformity index and bone mineral density at seven-year follow-up.</p> <p>Methods</p> <p>Ninety-one women examined two years after a low-energy vertebral or hip fracture were invited to a new examination seven years after the diagnosis. HRQOL was examined using the SF-36 questionnaire and was compared with an age and sex-matched reference group. Physical function was assessed using tests and questionnaires. Bone mineral density was measured. Radiographs of the spine were evaluated using the visual semiquantitative technique. A longitudinal and cross-sectional design was used in this study. Statistical analyses included descriptive statistics, Student's <it>t</it>-tests, ANCOVA, and partial correlation.</p> <p>Results</p> <p>Sixty-seven women participated. In the 42 women (mean age 75.8, SD 4.7) with vertebral fracture as inclusion fracture, bodily pain had deteriorated between two and seven years and might be explained by new fracture. Remaining pronounced reduction of HRQOL was seen in all domains except general health and mental health at seven-year follow-up in women with vertebral fractures compared to the reference group (p < 0.05). All 25 women (mean age 75.0, SD 4.7) with hip fracture as inclusion fracture had no significant changes in HRQOL between two and seven years and did not differ from the reference group regarding HRQOL after seven years. The vertebral group had significantly lower values for bodily pain, vitality, role-emotional function and mental health compared to the hip group. HRQOL showed a positive relationship between physical activity, static balance and handgrip strength.</p> <p>Conclusion</p> <p>The long-term reduction of HRQOL in women with vertebral fracture emerged clearly in this study. The relationships between HRQOL and physical performance in women with vertebral and hip fracture raise questions for more research.</p
Toward visualization of nanomachines in their native cellular environment
The cellular nanocosm is made up of numerous types of macromolecular complexes or biological nanomachines. These form functional modules that are organized into complex subcellular networks. Information on the ultra-structure of these nanomachines has mainly been obtained by analyzing isolated structures, using imaging techniques such as X-ray crystallography, NMR, or single particle electron microscopy (EM). Yet there is a strong need to image biological complexes in a native state and within a cellular environment, in order to gain a better understanding of their functions. Emerging methods in EM are now making this goal reachable. Cryo-electron tomography bypasses the need for conventional fixatives, dehydration and stains, so that a close-to-native environment is retained. As this technique is approaching macromolecular resolution, it is possible to create maps of individual macromolecular complexes. X-ray and NMR data can be ‘docked’ or fitted into the lower resolution particle density maps to create a macromolecular atlas of the cell under normal and pathological conditions. The majority of cells, however, are too thick to be imaged in an intact state and therefore methods such as ‘high pressure freezing’ with ‘freeze-substitution followed by room temperature plastic sectioning’ or ‘cryo-sectioning of unperturbed vitreous fully hydrated samples’ have been introduced for electron tomography. Here, we review methodological considerations for visualizing nanomachines in a close-to-physiological, cellular context. EM is in a renaissance, and further innovations and training in this field should be fully supported
Toxicity and cellular uptake of gold nanoparticles: what we have learned so far?
Gold nanoparticles have attracted enormous scientific and technological interest due to their ease of synthesis, chemical stability, and unique optical properties. Proof-of-concept studies demonstrate their biomedical applications in chemical sensing, biological imaging, drug delivery, and cancer treatment. Knowledge about their potential toxicity and health impact is essential before these nanomaterials can be used in real clinical settings. Furthermore, the underlying interactions of these nanomaterials with physiological fluids is a key feature of understanding their biological impact, and these interactions can perhaps be exploited to mitigate unwanted toxic effects. In this Perspective we discuss recent results that address the toxicity of gold nanoparticles both in vitro and in vivo, and we provide some experimental recommendations for future research at the interface of nanotechnology and biological systems
Transcriptional and Linkage Analyses Identify Loci that Mediate the Differential Macrophage Response to Inflammatory Stimuli and Infection
Macrophages display flexible activation states that range between pro-inflammatory (classical activation) and anti-inflammatory (alternative activation). These macrophage polarization states contribute to a variety of organismal phenotypes such as tissue remodeling and susceptibility to infectious and inflammatory diseases. Several macrophage- or immune-related genes have been shown to modulate infectious and inflammatory disease pathogenesis. However, the potential role that differences in macrophage activation phenotypes play in modulating differences in susceptibility to infectious and inflammatory disease is just emerging. We integrated transcriptional profiling and linkage analyses to determine the genetic basis for the differential murine macrophage response to inflammatory stimuli and to infection with the obligate intracellular parasite Toxoplasma gondii. We show that specific transcriptional programs, defined by distinct genomic loci, modulate macrophage activation phenotypes. In addition, we show that the difference between AJ and C57BL/6J macrophages in controlling Toxoplasma growth after stimulation with interferon gamma and tumor necrosis factor alpha mapped to chromosome 3, proximal to the Guanylate binding protein (Gbp) locus that is known to modulate the murine macrophage response to Toxoplasma. Using an shRNA-knockdown strategy, we show that the transcript levels of an RNA helicase, Ddx1, regulates strain differences in the amount of nitric oxide produced by macrophage after stimulation with interferon gamma and tumor necrosis factor. Our results provide a template for discovering candidate genes that modulate macrophage-mediated complex traits
Towards the Development of an Empirical Model for Islamic Corporate Social Responsibility: Evidence from the Middle East
Academic research suggests that variances in contextual dynamics, and more specifically religion, may lead to disparate perceptions and practices of corporate social responsibility (CSR). Driven by the increased geopolitical and economic importance of the Middle East and identified gaps in knowledge, the study aims to examine if indeed there is a divergent form of CSR exercised in the region. The study identifies unique CSR dimensions and constructs presented through an empirical framework in order to outline the practice and perception of CSR in a context with strong Islamic beliefs. The framework goes beyond the platform of mere Islamic philanthropy and is based on CSR-stakeholder management practices. Following an exploratory research design and collecting interview data from representatives of 63 organisations from Saudi Arabia, the United Arab Emirates and Oman, the study offers a snapshot of the CSR reality from the perspective of those living the phenomenon. The results suggest that the practice and perception of CSR in the examined context are largely grounded in the areas of social and altruistic actions but they cannot be examined in isolation from the religious context of CSR operation. This focus is mainly attributed to the dominant role of Islam in the examined sample, which leads to forms of non-structured or semi-structured approaches to CSR. Apart from the theoretical advancements offered to the CSR literature, the study also provides contributions for practitioners and policy makers.</p
Drug Resistance in Eukaryotic Microorganisms
Eukaryotic microbial pathogens are major contributors to illness and death globally. Although much of their impact can be controlled by drug therapy as with prokaryotic microorganisms, the emergence of drug resistance has threatened these treatment efforts. Here, we discuss the challenges posed by eukaryotic microbial pathogens and how these are similar to, or differ from, the challenges of prokaryotic antibiotic resistance. The therapies used for several major eukaryotic microorganisms are then detailed, and the mechanisms that they have evolved to overcome these therapies are described. The rapid emergence of resistance and the restricted pipeline of new drug therapies pose considerable risks to global health and are particularly acute in the developing world. Nonetheless, we detail how the integration of new technology, biological understanding, epidemiology and evolutionary analysis can help sustain existing therapies, anticipate the emergence of resistance or optimize the deployment of new therapies
Treatments for people who use anabolic androgenic steroids: a scoping review.
BACKGROUND: A growing body of evidence suggests that anabolic androgenic steroids (AAS) are used globally by a diverse population with varying motivations. Evidence has increased greatly in recent years to support understanding of this form of substance use and the associated health harms, but there remains little evidence regarding interventions to support cessation and treat the consequences of use. In this scoping review, we identify and describe what is known about interventions that aim to support and achieve cessation of AAS, and treat and prevent associated health problems. METHODS: A comprehensive search strategy was developed in four bibliographic databases, supported by an iterative citation searching process to identify eligible studies. Studies of any psychological or medical treatment interventions delivered in response to non-prescribed use of AAS or an associated harm in any setting were eligible. RESULTS: In total, 109 eligible studies were identified, which included case reports representing a diverse range of disciplines and sources. Studies predominantly focussed on treatments for harms associated with AAS use, with scant evidence on interventions to support cessation of AAS use or responding to dependence. The types of conditions requiring treatment included psychiatric, neuroendocrine, hepatic, kidney, cardiovascular, musculoskeletal and infectious. There was limited evidence of engagement with users or delivery of psychosocial interventions as part of treatment for any condition, and of harm reduction interventions initiated alongside, or following, treatment. Findings were limited throughout by the case report study designs and limited information was provided. CONCLUSION: This scoping review indicates that while a range of case reports describe treatments provided to AAS users, there is scarce evidence on treating dependence, managing withdrawal, or initiating behaviour change in users in any settings. Evidence is urgently required to support the development of effective services for users and of evidence-based guidance and interventions to respond to users in a range of healthcare settings. More consistent reporting in articles of whether engagement or assessment relating to AAS was initiated, and publication within broader health- or drug-related journals, will support development of the evidence base
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