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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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- Lee, Seung Joon, et al.
(författare)
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Microslit on a chip: A simplified filter to capture circulating tumor cells enlarged with microbeads
- 2019
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 14:10
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Tidskriftsartikel (refereegranskat)abstract
- Microchips are widely used to separate circulating tumor cells (CTCs) from whole blood by virtues of sophisticated manipulation for microparticles. Here, we present a chip with an 8 µm high and 27.9 mm wide slit to capture cancer cells bound to 3 µm beads. Apart from a higher purity and recovery rate, the slit design allows for simplified fabrication, easy cell imaging, less clogging, lower chamber pressure and, therefore, higher throughput. The beads were conjugated with anti-epithelial cell adhesion molecules (anti-EpCAM) to selectively bind to breast cancer cells (MCF-7) used to spike the whole blood. The diameter of the cell-bead construct was in average 23.1 µm, making them separable from other cells in the blood. As a result, the cancer cells were separated from 5 mL of whole blood with a purity of 52.0% and a recovery rate of 91.1%, and also we confirmed that the device can be applicable to clinical samples of human breast cancer patients. The simple design with microslit, by eliminating any high-aspect ratio features, is expected to reduce possible defects on the chip and, therefore, more suitable for mass production without false separation outputs.
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- Hyun, Sang-Min, et al.
(författare)
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Preparation, characterization, and evaluation of celecoxib eutectic mixtures with adipic acid/saccharin for improvement of wettability and dissolution rate
- 2019
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Ingår i: International Journal of Pharmaceutics. - : Elsevier. - 0378-5173 .- 1873-3476. ; 554, s. 61-71
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Tidskriftsartikel (refereegranskat)abstract
- Celecoxib (CEL) is a selective cyclooxygenase-2 (COX-2) inhibitor therapeutically indicated for the treatment of rheumatoid arthritis, osteoarthritis, acute pain, and inflammation. However, its poor solubility and dissolution rate significantly hinders its broader application. In this study, eutectic mixtures, as binary pharmaceutical compositions of CEL with adipic acid (ADI) and saccharin (SAC), were identified through a phase diagram and Tammann’s triangle intended to improve the wettability and dissolution rate of poorly water-soluble CEL. The contact angles at 0s in the liquid-solid interface were approximately θs (theta) 79.7° ± 0.50° and 86.65° ± 0.45° for CEL-ADI and CEL-SAC, respectively, which were much lower than the value obtained for CEL (92.05° ± 0.75° θ). Moreover, a comparison of the disk intrinsic dissolution rate and powder dissolution properties demonstrated that eutectic mixtures significantly increased the dissolution rate compared with CEL and physical mixtures. A general relationship was elucidated and indicated that the dissolution rate was increased as the contact angle decreased (correlation coefficient, r = 0.9966 ± 0.0031). Therefore, CEL-ADI and CEL-SAC eutectics may offer a novel formulation strategy to enhance the solubility and oral bioavailability of CEL.
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- Shin, Hyun Young, et al.
(författare)
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Cell Seeding Technology for Microarray-Based Quantitative Human Primary Skeletal Muscle Cell Analysis
- 2019
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Ingår i: Analytical Chemistry. - : AMER CHEMICAL SOC. - 0003-2700 .- 1520-6882. ; 91:22, s. 14214-14219
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Tidskriftsartikel (refereegranskat)abstract
- Pipetting techniques play a crucial role in obtaining reproducible and reliable results, especially when seeding cells on small target areas, such as on microarrays, biochips or microfabricated cell culture systems. For very rare cells, such as human primary skeletal muscle cells (skMCs), manual (freehand) cell seeding techniques invariably result in nonuniform cell spreading and heterogeneous cell densities, giving rise to undesirable variations in myogenesis and differentiation. To prevent such technique-dependent variation, we have designed and fabricated a simple, low-cost pipet guidance device (PGD), and holder that works with hand-held pipettes. This work validates the accuracy and reproducibility of the PGD platform and compares its effectiveness with manual and robotic seeding techniques. The PGD system ensures reproducibility of cell seeding, comparable to that of more expensive robotic dispensing systems, resulting in a high degree of cell uniformity and homogeneous cell densities, while also enabling cell community studies. As compared to freehand pipetting, PGD-assisted seeding of C2C12 mouse myoblasts showed 5.3 times more myotube formation and likewise myotubes derived from PGD-seeded human primary skMCs were 3.6 times thicker and 2.2 times longer. These results show that this novel, yet simple PGD-assisted pipetting technique provides precise cell seeding on small targets, ensuring reproducible and reliable high-throughput cell assays.
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