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- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 2. |
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| 3. |
- Yung, Marcus, et al.
(författare)
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Is there a u-shaped relationship between load levels and fatigue and recovery? : An examination of possible mechanisms
- 2023
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Ingår i: Ergonomics. - : Informa UK Limited. - 0014-0139 .- 1366-5847. ; , s. 1-16
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Tidskriftsartikel (refereegranskat)abstract
- In a previous study, an unexpected u-shaped relationship was observed between load level andfatigue/recovery responses. Moderate load levels resulted in lower perceived discomfort, pain,and fatigue, and shorter recovery times compared to either low or high load levels. Thisphenomenon has been reported in other studies, but no article has examined the possiblemechanisms that might explain this u-shaped relationship. In this paper, we re-examined thepreviously published data and found that the phenomenon does not appear to be due to theexperimental artefact; the u-shape may be due to unexpectedly lower fatigue effects at moderateloads, and higher fatigue effects at lower loads. We then conducted a literature review andidentified several possible physiological, perceptual, and biomechanical explanatory mechanisms.No single mechanism explains the entirety of the phenomenon. Further research is needed onthe relationship between work exposures, fatigue, and recovery, and the mechanisms related tothe u-shaped relationship.Practitioner summary: We examine a previously observed u-shaped relationship between loadlevel and fatigue/recovery, where moderate force resulted in lower perceived fatigue andshorter recovery times. A u-shaped fatigue response suggests that simply minimising load levelsmight not be an optimal approach to reduce the risk of workplace injuries.
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| 4. |
- Yung, Marcus, et al.
(författare)
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Variation of Force Amplitude and its Effects on Local Fatigue
- 2012
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Ingår i: European Journal of Applied Physiology. - : Springer Science and Business Media LLC. - 1439-6319 .- 1439-6327. ; 112:11, s. 3865-3879
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Tidskriftsartikel (refereegranskat)abstract
- Trends in industry are leaning towards stereotyped jobs with low workloads. Physical variation is an intervention to reduce fatigue and potentially musculoskeletal disorders in such jobs. Controlled laboratory studies have provided insight into the effectiveness of physical variation but very few have been devoted to intermittent activity without muscular rest as a component. This study was undertaken to determine whether the inclusion of muscular rest would result in physiological responses beyond those composed of varying non-zero forces. Five isometric contraction patterns with the same mean amplitude (15% maximum voluntary contraction, MVC), cycle time (6 seconds), and duty cycle (50%) were compared using multiple biophysical approaches. In exercise, sustained (15%Sust) and intermittent contractions including zero force (0%-30%Int) differed significantly in 19 of 27 response variables. Contractions varying by half the mean force (7.5%-22.5%Int) led to 8 and 7 measured responses that were significantly different from 0%-30%Int and 15%Sus, respectively. A sinusoidal condition (0%-30%Sine) resulted in 2 variables that were significantly different from 0%-30%Int and 16 different from 15%Sus. Finally, 10 response variables suggested that varying forces with 1% as the lower contraction level was significantly less fatiguing than 15%Sus while no responses were significantly different from 0%-30%Int. Sustained contractions led to decreased twitch force 24 hours post-exercise whereas intermittent contractions recovered within 60 minutes. This suggests that time varying force may be a useful intervention to reduce local fatigue in workers performing low-load tasks and that rest per se did not seem to cause any extraordinary effects.
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