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Topic Review
Elongational Stresses and Cells
Shear often attributed as being the main source of cell deformation/damage in devices like prosthetic heart valves and artificial organs. Less well understood and studied are extensional stresses which are often found in such devices, in bioreactors, and in normal blood circulation. Several microfluidic channels utilizing hyperbolic, abrupt, or tapered constrictions and cross-flow geometries, have been used to isolate the effects of extensional flow. Under such flow cell deformations, erythrocytes, leukocytes, and a variety of other cell types have been examined. Results suggest that extensional stresses cause larger deformation than shear stresses of the same magnitude. This has further implications in assessing cell injury from mechanical forces in artificial organs and bioreactors. The cells’ greater sensitivity to extensional stress has found utility in mechanophenotyping devices, which have been successfully used to identify pathologies that affect cell deformability. Further application outside of biology includes disrupting cells for increased food product stability and harvesting macromolecules for biofuel. 
  • 369
  • 08 Oct 2021
Topic Review
Calcium Signaling Regulates Autophagy
Calcium (Ca2+) functions as a second messenger that is critical in regulating fundamental physiological functions such as cell growth/development, cell survival, neuronal development and/or the maintenance of cellular functions. The coordination among various proteins/pumps/Ca2+ channels and Ca2+ storage in various organelles is critical in maintaining cytosolic Ca2+ levels that provide the spatial resolution needed for cellular homeostasis. An important regulatory aspect of Ca2+ homeostasis is a store-operated Ca2+ entry (SOCE) mechanism that is activated by the depletion of Ca2+ from internal ER stores and has gained much attention for influencing functions in both excitable and non-excitable cells.
  • 412
  • 08 Oct 2021
Topic Review
Cell Mechanics in Embryoid Bodies
Embryoid bodies (EBs) resemble self-organizing aggregates of pluripotent stem cells that recapitulate some aspects of early embryogenesis. Within few days, the cells undergo a transition from rather homogeneous epithelial-like pluripotent stem cell colonies into a three-dimensional organization of various cell types with multifaceted cell–cell interactions and lumen formation—a process associated with repetitive epithelial-mesenchymal transitions. In the last few years, culture methods have further evolved to better control EB size, growth, cellular composition, and organization—e.g., by the addition of morphogens or different extracellular matrix molecules. There is a growing perception that the mechanical properties, cell mechanics, and cell signaling during EB development are also influenced by physical cues to better guide lineage specification; substrate elasticity and topography are relevant, as well as shear stress and mechanical strain. Epithelial structures outside and inside EBs support the integrity of the cell aggregates and counteract mechanical stress. Furthermore, hydrogels can be used to better control the organization and lineage-specific differentiation of EBs. In this review, we summarize how EB formation is accompanied by a variety of biomechanical parameters that need to be considered for the directed and reproducible self-organization of early cell fate decisions.
  • 543
  • 08 Oct 2021
Topic Review
L-Lactate
l-Lactate plays a role as a metabolic and signaling molecule, accordingly, Vaccari-Cardoso and co-workers developed a viral vector to express a modified version of lactate oxidase (LOx) originating from the bacteria Aerococcus viridans. Their results in vitro show that LOx expression in astrocytes reduced their intracellular lactate levels and its release to the extracellular space.
  • 607
  • 07 Oct 2021
Topic Review
Free Radicals
Free radicals are atoms, molecules or ions with one or more unpaired electrons. The most reactive ones have high reduction potentials; i.e., they readily oxidize most molecules indiscriminately. There is a common misconception that all free radicals are highly reactive, but in fact the range of those able to cause biological damage is quite narrow: it is made up principally of hydroxyl, peroxyl, alkoxyl, thiyl, phenoxyl and semiquinone free radicals, and high valence transition ions.
  • 1.2K
  • 07 Oct 2021
Topic Review
Dictyostelium as a Drug Resource
The cellular slime mold Dictyostelium discoideum is an excellent model organism for the study of cell and developmental biology because of its simple life cycle and ease of use. Recent findings suggest that Dictyostelium and possibly other genera of cellular slime molds, are potential sources of novel lead compounds for pharmacological and medical research.
  • 560
  • 02 Oct 2021
Topic Review
MicroRNA Processing by Dicer
MicroRNAs (miRNAs) are small non-coding RNAs that are about 22 nucleotides in length. They regulate gene expression post-transcriptionally with the effector protein complex, containing Argonaute or trinucleotide repeat containing 6 (TNRC6) proteins, and target mRNAs in a sequence-dependent manner, causing the translational repression and destabilization of the target mRNAs. Both Drosha and Dicer, members of the RNase III family proteins, are essential components in the canonical miRNA biogenesis pathway. miRNA is transcribed into primary-miRNA (pri-miRNA) from genomic DNA. Drosha then cleaves the flanking regions of pri-miRNA into precursor-miRNA (pre-miRNA), while Dicer cleaves the loop region of the pre-miRNA to form a miRNA duplex. In this report, we summarized and discussed the current reports in which double-stranded RNA binding proteins (dsRBPs), such as TAR RNA binding protein (TRBP) or the adenosine deaminase acting on RNA (ADAR), modulate the processing of miRNA by Dicer in various manners. 
  • 1.4K
  • 01 Oct 2021
Topic Review
Mucociliary clearance
Mucociliary clearance constitutes an innate lung defense mechanism that is primarily driven by ciliated cells. Respiratory mucus traps pathogens entering the airways, and lung cilia propel them outward via their coordinated directional motion. Thus, damage to the component(s) of this apparatus is averted and physiological function is ensured. 
  • 874
  • 30 Sep 2021
Topic Review
Ginseng against Respiratory Tract Infections
Ginseng has been reported to inhibit bacterial pathways, thereby killing bacteria indirectly. It has also been shown to protect the host from bacterial invasion.
  • 1.0K
  • 30 Sep 2021
Topic Review
PTP1B
The tyrosine phosphatase 1B (PTP1B) acts as a key negative regulator of insulin receptor, and a plethora of studies confirmed that uncontrolled activity of this enzyme is one of the main causes that lead to IR (insulin resistance). According to this hypothesis, it has been demonstrated that the overexpression of PTP1B promotes IR in liver, muscle, adipose tissue, pancreas, and brain.
  • 378
  • 29 Sep 2021
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