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Topic review
Updated time: 06 May 2021
Submitted by: Hyun-Jae Shin
Definition: Quercetin is a well-known plant flavonol and antioxidant; however, there has been some debate regarding the efficacy and safety of native quercetin as a skin-whitening agent via tyrosinase inhibition. Several researchers have synthesized quercetin derivatives as low-toxicity antioxidants and whitening agents. However, no suitable quercetin derivatives have been reported to date. In this study, a novel quercetin derivative was synthesized by the SN2 reaction using quercetin and oleyl bromide. The relationship between the structures and activities of quercetin derivatives as anti-melanogenic agents was assessed using in vitro enzyme kinetics, molecular docking, and quenching studies; cell line experiments; and in vivo zebrafish model studies. Novel 3,7-dioleylquercetin (OQ) exhibited a low cytotoxic concentration level at >100 µg/mL (125 µM), which is five times less toxic than native quercetin.
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Topic review
Updated time: 24 Feb 2021
Submitted by: Georgia Pennarossa
Definition: Bi-dimensional culture systems have represented the most used method to study cell biology outside the body for over a century. Although they convey useful information, such systems may lose tissue-specific architecture, biomechanical effectors, and biochemical cues deriving from the native extracellular matrix, with significant alterations in several cellular functions and processes. Notably, the introduction of three-dimensional (3D) platforms that are able to re-create in vitro the structures of the native tissue, have overcome some of these issues, since they better mimic the in vivo milieu and reduce the gap between the cell culture ambient and the tissue environment. 3D culture systems are currently used in a broad range of studies, from cancer and stem cell biology, to drug testing and discovery.
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Topic review
Updated time: 27 Oct 2020
Submitted by: Van-An Duong
Definition: Three-dimensional liquid chromatography (3D-LC) is the consecutive combination of 3 independent LC techniques to decrease the complexity of proteome digest samples. 3D-LC systems can be performed in an online or offline manner. Ideally, each dimension in a 3D-LC system is completely orthogonal to the others.
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Topic review
Updated time: 14 Apr 2021
Submitted by: Federica Cherchi
Definition: Adenosine is a signalling molecule which, by activating specific membrane receptors, acts as an important player during brain insults such as ischemia. or demyelinating injuries. Here we review data in the literature describing A2B receptor-mediated effects in preclinical in vitro and in vivo models of cerebral ischemia and myelination that point to A2B receptor ligands as putative therapeutic targets for the still unmet treatment of stroke or demyelinating diseases.
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Topic review
Updated time: 11 May 2021
Submitted by: László Homolya
Definition: The ABCG2 (also named breast cancer resistance protein—BCRP, or mitoxantrone resistance protein—MXR) is an integral membrane protein belonging to the ABC (ATP-binding cassette) protein superfamily. ABCG2 is an active transporter utilizing the energy of ATP binding and hydrolysis to translocate various substrate molecules across the plasma membrane from the cells to the extracellular space. Its transported substrates include endobiotics (endogenous substances), such as uric acid, as well as xenobiotics, such as anti-cancer drugs. ABCG2 plays a pivotal role in uric acid clearance; thus, its malfunction may lead to hyperuricemia and gout. On the other hand, ABCG2 residing in various barrier tissues is involved in the innate defense mechanisms of the body, influencing the absorption, distribution, excretion of potentially toxic endo- and exogenous compounds.
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Topic review
Updated time: 26 Oct 2020
Submitted by: Hilary Weidner
Definition: The most common bone disease in humans is osteoporosis (OP). Current therapeutics targeting OP have several negative side effects. Bone morphogenetic protein 2 (BMP2) is a potent growth factor that is known to activate both osteoblasts and osteoclasts. It completes these actions through both SMAD-dependent and SMAD-independent signaling. A novel interaction between the BMP type Ia receptor (BMPRIa) and casein kinase II (CK2) was discovered, and several CK2 phosphorylation sites were identified. A corresponding blocking peptide (named CK2.3) was designed to further elucidate the phosphorylation site’s function. Previously, CK2.3 demonstrated an increased osteoblast activity and decreased osteoclast activity in a variety of animal models, cell lines, and isolated human osteoblasts. It is hypothesized that CK2.3 completes these actions through the BMP signaling pathway. Furthermore, it was recently discovered that BMP2 did not elicit an osteogenic response in osteoblasts from patients diagnosed with OP, while CK2.3 did.
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Topic review
Updated time: 18 Dec 2020
Submitted by: Amar U. Kishan
Definition: Prostate cancer (PCa) is the most common noncutaneous solid organ malignancy among men worldwide. Radiation therapy is a standard of care treatment option that has historically been delivered in the form of small daily doses of radiation over the span of multiple weeks. PCa appears to have a unique sensitivity to higher doses of radiation per fraction, rendering it susceptible to abbreviated forms of treatment. Stereotactic body radiation therapy (SBRT) and high-dose-rate brachytherapy (HDRBT) are both modern radiation modalities that allow the precise delivery of ablative doses of radiation to the prostate while maximally sparing sensitive surrounding normal structures. In this review, we highlight the evidence regarding the radiobiology, oncological outcomes, toxicity and dose/fractionation schemes of SBRT and HDRBT monotherapy in men with low-and intermediate-risk PCa.
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Topic review
Updated time: 23 Feb 2021
Submitted by: Yi Qu
Definition: Angiotensin-Converting Enzyme 2 (ACE2) is an essential enzyme in the renin-angiotensin system (RAS), effectively maintaining RAS equilibrium. Recently, scientists have also found that through the mediation of the S protein, SARS-CoV-2 can invade host cells using ACE2 as the target.
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Topic review
Updated time: 12 May 2021
Submitted by: Xiang-Ping Chu
Definition: Acid-sensing ion channels (ASICs) are mainly proton-gated cation channels, which can be activated by a drop in extracellular pH below 7.0 and triggered by nonproton ligands during physiological pH levels.
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Topic review
Updated time: 19 Mar 2021
Submitted by: Cátia Teixeira
Definition: Malaria is among the deadliest infectious diseases in the world caused by Plasmodium parasites.
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