Multiple roles of reactive oxygen species (ROS) and their consequences for health and disease are emerging throughout biological sciences. This development has led researchers unfamiliar with the ...complexities of ROS and their reactions to employ commercial kits and probes to measure ROS and oxidative damage inappropriately, treating ROS (a generic abbreviation) as if it were a discrete molecular entity. Unfortunately, the application and interpretation of these measurements are fraught with challenges and limitations. This can lead to misleading claims entering the literature and impeding progress, despite a well-established body of knowledge on how best to assess individual ROS, their reactions, role as signalling molecules and the oxidative damage that they can cause. In this consensus statement we illuminate problems that can arise with many commonly used approaches for measurement of ROS and oxidative damage, and propose guidelines for best practice. We hope that these strategies will be useful to those who find their research requiring assessment of ROS, oxidative damage and redox signalling in cells and in vivo.
Increasing concentrations of organic micropollutants, like pharmaceuticals, in surface water may require additional treatment for drinking water production. The UV/H2O2 process is very effective for ...this purpose, but is known for its relatively high energy demand. This energy demand may be decreased by improving the water matrix composition and/or by optimizing UV reactor geometry. Thus, operational costs of the process may be decreased. This can be visualized by calculating the Electrical Energy per Order (EEO). By optimizing the water matrix, e.g. by pretreating the water by filtration over activated carbon or with O3/H2O2, the energy demand decreased up to 70%. This is affected by the concentration and type of the natural organic matter present. By optimizing reactor geometry an additional decrease in energy demand, up to 40%, could be obtained. How efficient the process may become strongly depends on the characteristics of the micropollutants involved.
Age‐associated loss of muscle mass and function (sarcopenia) has a profound effect on the quality of life in the elderly. Our previous studies show that CuZnSOD deletion in mice (Sod1−/− mice) ...recapitulates sarcopenia phenotypes, including elevated oxidative stress and accelerated muscle atrophy, weakness, and disruption of neuromuscular junctions (NMJs). To determine whether deletion of Sod1 initiated in neurons in adult mice is sufficient to induce muscle atrophy, we treated young (2‐ to 4‐month‐old) Sod1flox/SlickHCre mice with tamoxifen to generate i‐mn‐Sod1KO mice. CuZnSOD protein was 40‐50% lower in neuronal tissue in i‐mn‐Sod1KO mice. Motor neuron number in ventral spinal cord was reduced 28% at 10 months and more than 50% in 18‐ to 22‐month‐old i‐mn‐Sod1KO mice. By 24 months, 22% of NMJs in i‐mn‐Sod1KO mice displayed a complete lack of innervation and deficits in specific force that are partially reversed by direct muscle stimulation, supporting the loss of NMJ structure and function. Muscle mass was significantly reduced by 16 months of age and further decreased at 24 months of age. Overall, our findings show that neuronal‐specific deletion of CuZnSOD is sufficient to cause motor neuron loss in young mice, but that NMJ disruption, muscle atrophy, and weakness are not evident until past middle age. These results suggest that loss of innervation is critical but may not be sufficient until the muscle reaches a threshold beyond which it cannot compensate for neuronal loss or rescue additional fibers past the maximum size of the motor unit.
Using deletion of CuZnSOD in motor neurons to induce increased oxidative stress and mimic loss of motor neurons in spinal cord, we show that neuronal loss induces NMJ disruption that progresses over time to cause muscle atrophy and weakness in i‐mn‐Sod1KO mice. The delay between loss of motor neuron number and significant atrophy and weakness suggests there are compensatory mechanisms at play to mitigate the impact of reduced innervation (possibly including increased sprouting) that eventually fail over time.
Green space matters for mental health but is under constant pressure in an increasingly urbanising world. Often there is little space available in cities for green areas, so it is vital to optimise ...the design and usage of these available green spaces. To achieve this, experts in planning, design and nature conservation need to know which types and characteristics of green spaces are most beneficial for residents' mental health.
A scoping review of studies that compare different green space types and characteristics on mental health was conducted. A total of 215 (experimental, observational and qualitative) papers were included in the scoping review.
This review highlights a high level of heterogeneity in study design, geographical locations, mental health outcomes and green space measures. Few of the included studies were specifically designed to enable direct comparisons between green space types and characteristics (e.g. between parks and forests). The included studies have predominantly experimental research designs looking at the effects of short‐term exposure to green space on short‐term mental health outcomes (e.g. affect and physiological stress). More studies enabled only indirect comparisons, either within the same study or between different studies.
Analysis of the direction of the mental health outcomes (positive, neutral, negative) from exposure to various types and characteristics of green space found positive (i.e. beneficial) effects across all green space types. However, green space characteristics did appear to render more diverse effects on mental health, which is especially the case for vegetation characteristics (e.g. higher vegetation density can be negative for mental health).
The scoping review reveals gaps in the present evidence base, with a specific need for more studies directly comparing green space types and characteristics within the same study. Proposed future research directions include the use of longitudinal research designs focusing on green space characteristics, considering actual exposure and systematically addressing heterogeneity in factors influencing the relation between green spaces and mental health (e.g. type of interaction, user experience).
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Summary
Oxidative modification of cellular components may contribute to tissue dysfunction during aging. In skeletal muscle, contractile activity increases the generation of reactive oxygen and ...nitrogen species (ROS). The question of whether contraction‐induced ROS generation is further increased in skeletal muscle of the elderly is important since this influences recommendations on their exercise participation. Three different approaches were used to examine whether aging influences contraction‐induced ROS generation. Hind limb muscles of adult and old mice underwent a 15‐min period of isometric contractions and we examined ROS generation by isolated skeletal muscle mitochondria, ROS release into the muscle extracellular fluid using microdialysis techniques, and the muscle glutathione and protein thiol contents. Resting skeletal muscle of old mice compared with adult mice showed increased ROS release from isolated mitochondria, but no changes in the extracellular levels of superoxide, nitric oxide, hydrogen peroxide, hydroxyl radical activity or muscle glutathione and protein thiol contents. Skeletal muscle mitochondria isolated from both adult and old mice after contractile activity showed significant increases in hydrogen peroxide release compared with pre‐contraction values. Contractions increased extracellular hydroxyl radical activity in adult and old mice, but had no significant effect on extracellular hydrogen peroxide or nitric oxide in either group. In adult mice only, contractile activity increased the skeletal muscle release of superoxide. A similar decrease in muscle glutathione and protein thiol contents was seen in adult and old mice following contractions. Thus, contractile activity increased skeletal muscle ROS generation in both adult and old mice with no evidence for an age‐related exacerbation of ROS generation.
It is often assumed that the way teachers approach their teaching is determined by the way they think about learning. This study explores how teachers of an undergraduate medical programme (UMP) ...think about learning, how they approach teaching and whether their conceptions of learning relate to their teaching approaches.
Quantitative data of academic teachers involved in the undergraduate programme in medicine were collected and analysed. We used a questionnaire designed to measure teachers' conceptions of their own learning (COL) and of student learning as well as teachers' approaches to teaching (AT).
Teachers of the medical undergraduate programme hold a variety of COL, of how students learn and their AT. No significant correlations were found between teachers' conceptions of learning and their AT.
Although UMP teachers' ideas on learning and teaching are very diverse, some of their conceptions are interrelated. Teachers' ideas on their own learning is sometimes - but not always - related to how they think about student learning. But most importantly, the way UMP teachers think about learning is not automatically converted into the way they approach teaching.
Summary
Reasons for performing study: Lateral heel wedges are used to treat horses and ponies with patella fixation or bone spavin. However, these therapies are purely empirically based and lack ...scientific evidence.
Objectives: Lateral heel wedges would change joint motion in the sagittal, but mainly in the transversal planes, in healthy horses. This effect would be increased by restricted feeding and decreased by extra training.
Methods: Agroup of 24 Shetland ponies age 3 years was used, as foals had been assigned to restricted and ad libitum (ad lib) feeding, and low and high level training groups of 6 animals each. An experienced judge evaluated passive patella luxation in the square standing pony, using a score of 0 (normal) to 4 (stationary patella luxation). The motion of the markers, glued to the skin covering skeletal landmarks on the left fore‐ and hindlimbs, was recorded 3 dimensionally at a frequency of 300 Hz using a modified CODA‐3 apparatus while trotting on a treadmill at a speed of 3.0 m/sec, before and directly after 5o lateral heel wedges had been applied to the hindlimbs. After data analysis, the kinematic variables in the sagittal and transversal plane, under these 3 conditions (wedge, feeding, training), were compared statistically using a multivariate repeated measures analysis, general linear model (P < 0.05).
Results: In the sagittal plane, an acute change in hind hoof conformation resulted in a less animated trot with a less protracted forelimb and less hindlimb flexion. This is similar, although less pronounced, to the decrease in limb flexion reported previously as a result of restricted feeding. More specifically, lateral heel wedges resulted in significant changes in the transversal plane angles of all joints in the hindlimb. The stifle joint became maximally 1.8o more adducted just before the end of the stance phase, while the tarsal joint was 2.9o and fetlock joint 4.7o more abducted (P < 0.05). In the restricted feeding group, stifle joint adduction was 8.5o and tarsal joint abduction 5.6o larger than in the ad libitum feeding group (P < 0.05). The patella luxation score was also significant ly higher in this group (1.8) compared to ponies fed ad libitum (0.9).
Conclusions: The acute effects of lateral heel wedges on the equine locomotor system in the transversal plane movement relieve tension from the medial patellar ligament and decrease pressure on the medial side of the tarsal joint. However, the fetlock joint experiences considerably more out of plane stress. Poor body condition resulted in a 2x worse patella luxation score, while the effect on stifle and tarsal joint movement in the transversal plane was almost 5x and 2x larger, respectively, than a lateral wedge.
Potential relevance: The clinical importance of general body condition for maintaining lateral stability in the equine hindlimbs is established, but future research may prove that wedges are beneficial to treat patella fixation and bone spavin in the long term.
Glutathione peroxidase 4 (Gpx4) is uniquely involved in the detoxification of oxidative damage to membrane lipids. Our previous studies showed that Gpx4 is essential for mouse survival and that Gpx4 ...deficiency makes cells vulnerable to oxidative injury. In the present study, we generated two lines of transgenic mice overexpressing Gpx4 (Tg(GPX4) mice) using a genomic clone containing the human GPX4 gene. Both lines of Tg-(GPX4) mice, Tg5 and Tg6, had elevated levels of Gpx4 (mRNA and protein) in all tissues investigated, and overexpression of Gpx4 did not cause alterations in activities of glutathione peroxidase 1, catalase, Cu/Zn superoxide dismutase, and manganese superoxide dismutase. The human GPX4 transgene rescued the lethal phenotype of null mutation of the mouse Gpx4 gene, indicating that the transgene can replace the essential role of mouse Gpx4 in mouse development. Cell death induced by t-butylhydroperoxide and diquat was significantly less in murine embryonic fibroblasts from Tg(GPX4) mice compared with wild type mice. Liver damage and lipid peroxidation induced by diquat were reduced significantly in Tg(GPX4) mice. In addition, diquat-induced apoptosis was decreased in Tg(GPX4) mice, as evidenced by attenuated caspase-3 activation and reduced cytochrome c release from mitochondria. These data demonstrate that Gpx4 plays a role in vivo in the mechanism of apoptosis induced by oxidative stress that most likely occurs through oxidative damage to mitochondrial phospholipids such as cardiolipin.
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