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Cobalt Toxicity and Human Health
Published in Debasis Bagchi, Manashi Bagchi, Metal Toxicology Handbook, 2020
Md. Hafiz Uddin, Marufa Rumman
Co3O4-NPs are usually used in industry and in biomedicine, and skin absorption of these NPs is a deep concern. The workers and users can be exposed to Co3O4-NPs via powders or solutions. Studies demonstrated that Co3O4-NPs cannot penetrate Franz diffusion intact skin cells but able to penetrate when a damaged skin protocol is used. A long-term exposure to Co3O4-NPs (1,000 mg/L) induces cell damage and necrosis in cultured keratinocytes. The findings showed that a long-term exposure (7 days) can induce a dose-dependent cell viability reduction (effective concentration-50 (EC50) values: 1.3 × 10−4 M; MTT essay; 3.7 × 105 M, AlamarBlue® assay) that seems to be associated to necrotic events (EC50 value: 1.3 × 104 M, PI assay). It is recommended that study workers, and atopic subjects should use personal protective equipment to avoid contamination of the skin with Co3O4-NPs [40].
In Vivo Assessment
Published in Karen J.L. Burg, Didier Dréau, Timothy Burg, Engineering 3D Tissue Test Systems, 2017
Maria Yanez, Scott Collins, Thomas Boland
There are different surgical procedures to remove the malignant cells such as lumpectomy, partial mastectomy (quadrantectomy mastectomy), simple mastectomy, modified radical mastectomy, and radical mastectomy. Currently, women undergo different procedures for breast reconstruction, including tissue flap procedures, graft for tissue support, and cell suspension injection after a liposuction (Miller et al. 2016; Riccio et al. 2015). These procedures have different problems associated with hernia, limited to high donor site morbidity, cell damage during liposuction, necrosis postinjection, and often implants are avoided while undergoing radiation treatments. Besides breast reconstruction, the majority of mastectomy cases also require nipple/areola reconstruction. Nipple sparing mastectomies in small-to-moderate size breast typically render the best cosmetic outcomes, though there are not always good results due to the nature of breast cancer. Results of available nipple areola complex (NAC) reconstruction techniques can be unpredictable. There are many different techniques, including nipple sharing, free-composite grafts, and local “pull-out” flaps, all of which are vulnerable to an unpredictable degree of loss (shape and volume), and in most cases require a second procedure.
Enzyme Kinetics and Drugs as Enzyme Inhibitors
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2019
Several diseases such as cancer, sepsis, AIDS, renal failure, diabetes are associated with an atrophy of skeletal muscle resulting from a depression of protein synthesis in skeletal muscle as well as from an increase in protein degradation due to an enhanced activity of the ubiquitin-proteasome proteolytic pathway (e.g., Tisdale, 2005; Mitchell, 2003). Proteasomes are large, barrel-like complexes located in the cell nucleus and the cytoplasm of eukaryotes and other organisms; they catalyze the hydrolysis of proteins to peptides after being tagged covalently with ubiquitin (abbr. Ub or Q). Protein molecules, remaining misfolded, are removed after being tagged covalently with ubiquitin from the endoplasmic reticulum (ER) across the membrane for proteasomal degradation, a pathway elucidated by Aaron Ciechanover and Avram Hershko, honored with the Nobel Price of Chemistry in 2004 (e.g., Herschko and Ciechanover, 1998). For details concerning quality control and ER-associated degradation see, e.g., Olivari and Molinari (2007) or Lederkremer (2007) and Grunwald (2016). The 26S-proteasome, is a multisubunit enzyme complex consisting of a catalytic 20S-subunit (opposite scheme) with 28 (14 α- and 14 β-) homolog subunits; the 20S core is caped at each terminus with a regulatory 19S particle that binds specifically to PUCs (polyubiquitinated chains) and contains six different ATPases (Rpt 1–6 ATP) belonging to the AAA-class (ATPases with various cellular activities). An accumulation of misfolded proteins leads to disturbance of the ER homeostasis accompanied by cell damage.
Silver-based nanomaterials: A critical review on factors affecting water disinfection performance and silver release
Published in Critical Reviews in Environmental Science and Technology, 2021
Ecem Bahcelioglu, Husnu Emrah Unalan, Tuba Hande Erguder
Silver (Ag) has been known as a robust antimicrobial agent (El-Aassar et al., 2013; Wong & Liu, 2010) since the ancient times and was used to prevent infections in water containers and putrefaction (Rai et al., 2009; Silvestry-Rodriques, Sicairos-Ruelas, Gerba, & Bright, 2007). Although microbial inactivation of Ag has been known for centuries, its mechanism in both macro and nanoscale has not been fully understood. It is known that structural and morphological changes occur in bacteria due to Ag ions released from the macro or nanosilver. It is also known that nanosilver releases more ions per unit mass due to its higher surface area to volume ratio compared to macrosilver (Stabryla et al., 2018). The most commonly accepted mechanisms of action are cell membrane damage, DNA damage and the generation of reactive oxygen species (ROS). All may result in cell damage and death. Figure 1-a schematically shows different antibacterial mechanisms of Ag ions released from nanosilver. The major mechanisms of Ag as reported in the literature to date are
Isolation, structure characterization and prediction of antioxidant activity of two new compounds from the leaves of Dodonaea viscosa native to the Sultanate of Oman
Published in Egyptian Journal of Basic and Applied Sciences, 2018
Asila Ahmed Salim Al Habsi, Mohammad Amzad Hossain
Plants are considered as essential source of medicines for humans. Plant parts like leaves, flowers, roots, stems, seeds, and fruit are used as food resources for human as well as safe medicine for the treatment of different diseases. Plant-derived herbal medicine is used as main sources for the treatment of diseases since the ancient time [1]. Antioxidants are the most important chemical components that may prevent or delay different types of cell damage. Foods, fruits, and vegetables are the main sources of natural antioxidants. The prevention or recovery of cell damage in the human body could be used foods, fruits, and vegetables as natural antioxidants. The main mechanism of antioxidants is to improve the immune system in the human body by producing the free radical. Some of natural antioxidants are also available as dietary supplements. Recently, vegetables and fruits are considered as rich sources of natural antioxidants. Several recent scientific evidences are available that eating lots of vegetables and fruits are very good sources for human health and to prevent the cell damage. Therefore, the risks of certain chronic or incurable diseases are lowered due to natural antioxidants [2].