China
Africa
Explore chapters and articles related to this topic
Nanomedicines for the Treatment of Respiratory Diseases
Published in Sarwar Beg, Mahfoozur Rahman, Md. Abul Barkat, Farhan J. Ahmad, Nanomedicine for the Treatment of Disease, 2019
Brahmeshwar Mishra, Sundeep Chaurasia
The major component of airway mucus is made up of large, oligomeric, gel-forming mucin glycoproteins with molar masses ranging between 10 and 40 million Da (Davies et al., 1996; Gupta and Jentoft, 1992; Thornton et al., 1990, 1991). A number of different mucin proteins which are products of different genes have been identified in the respiratory tract so far. The mucins are produced primarily by two different airway cell types: goblet cells and glandular cells. While MUC2 and MUC5AC expression has been localized to cells of the surface epithelium (Groneberg et al., 2002; Davies et al., 1996; Chung et al., 2004; Li et al., 1997; Wickstrom et al., 1998), MUC5B and MUC7 mucins are expressed primarily in glandular cells (Wickstrom et al., 1998; Groneberg et al., 2003; Sharma et al., 1998), but can also be induced in epithelial cells under states of inflammation (Groneberg et al., 2002). Out of the different respiratory mucins, MUC5AC and MUC5B have been identified as major gel-forming mucins whereas MUC2 contributes only to a lesser extent to the matrix (Davies et al., 1996).
Wood Adhesives Containing Proteins and Carbohydrates
Published in Zhongqi He, Bio-based Wood Adhesives, 2017
In nature, cell surface glycoproteins exhibit adhesive properties (Von der Mark and Sorokin, 2002; Xu and Mosher, 2011). For example, the integrins can mediate adhesion to extracellular matrix and cell-cell interactions. The cadherins are glycoproteins present in tissues that are involved in cell adhesion together with Ca++ ions. The selectins are a family of cell adhesion molecules that bind to mucins. The immunoglobulins are involved in the recognition, binding, or adhesion processes of cells through antibodies. Mucins (commonly found in mucous membranes or saliva) contain glycoproteins that can cause the formation of a gel-like material that helps bioadhesion (Smart, 2005). The glue on spider web contains glycoproteins (Stellwagen et al., 2015). Likewise the glue in silk contains glycoproteins (Dutta et al., 2012). The structure and function of adhesive gels produced from invertebrates were reviewed by Smith (2002).
Hydrophobe Modified Cationic Polysaccharides for Topical Microbicide Delivery
Published in Raphael M. Ottenbrite, Sung Wan Kim, Polymeric Drugs & Drug Delivery Systems, 2019
George L. Brode, Gustavo F. Doncel, John E. Kemnitzer
The chemistry of the substrate, mucosa, was a primary consideration in the design of the delivery system. Mucins, whether gastrointestinal, respiratory, ophthamological, cervical, or vaginal, are glycoproteins whose major function is to protect the epithelial surface [28]. These extremely hydrophilic substances are composed of a polypeptide backbone covalently linked to oligosaccharide and polysaccharide units carrying a negative charge, with sialic acid being present in all mucins and mainly responsible for their anionic nature (pH 4.5) [29]. It is also interesting to note that it has been observed that no significant differences in mucin composition are found in women belonging to different blood groups [30].
Influence of o,p′-DDT on MUC5AC expression via regulation of NF-κB/AP-1 activation in human lung epithelial cells
Published in Journal of Toxicology and Environmental Health, Part A, 2021
Gi Ho Lee, Sun Woo Jin, Jae Ho Choi, Eun Hee Han, Yong Pil Hwang, Chul Yung Choi, Hye Gwang Jeong
Airway mucus is a complex hydrophilic gel composed of mucins, proteins, salts, lipids, and water. Mucins are high-molecular-weight glycoproteins composed of repeating structures with varying numbers of specific amino acids including serine, threonine, and proline (Kim 2012). At least 16 mucin genes are expressed in the human lung (MUC1, 2, 4, 5AC, 5B, 7, 8, 11, 13, 15, 16, 18, 19, 20, 21, and 22) (Davies et al. 2007; Rose and Voynow 2006). Mucin 5AC (MUC5AC) is a major gel-forming mucin present in secretions from goblet cells, and its expression is inducible during airway inflammation (Choi et al. 2011). Inflammatory mediators including phorbol myristate acetate (PMA) and tumor necrosis factor-α (TNF-α) induce airway MUC5AC formation through the activity of transcription factors, including nuclear factor kappa-b (NF-κB), activator protein 1 (AP-1), and specificity protein-1(SP-1) (Choi et al. 2011; Hewson, Edbrooke, and Johnston 2004; Lim et al. 2009). Further, oxidants generated from irritant chemicals, such as cigarette smoke and fine particulate matter, produce lung inflammation via reactive oxygen species, Akt, and the mitogen-activated protein kinase (MAPK) signaling pathway in lung epithelial cells (Arooj et al. 2020; Kovacic and Somanathan 2009; Lee et al. 2019; Liu et al. 2018; Mossman, Lounsbury, and Reddy 2006).
Preparation, characterization, and in vitro drug release behavior of thiolated alginate nanoparticles loaded budesonide as a potential drug delivery system toward inflammatory bowel diseases
Published in Journal of Biomaterials Science, Polymer Edition, 2020
Muhammad Arif, Zhe Chi, Yong-Jun Liu, Chen-Guang Liu
Mucins formed by goblet cells in the intestinal epithelium are a highly glycosylated polymer that is the primary component of mucus. Assessing the mucoadhesion of Alg-Cys nanoparticles using the mucin adsorption assay showed that Alg-Cys exhibited increased mucin adsorption compared to Alg particles (Figure 8), suggesting that thiolation improved intestinal mucoadhesion [29]. Figure 8 shows that the adsorption rate of mucin on nanoparticles with the same degree of substitution at pH = 7.4 is significantly higher than that at pH = 2, which is related to the tendency of sulfhydryl groups at different pH values. It has been pointed out that in solutions with pH less than 4, sulfhydryl groups tend to exist in the form of reductions, i.e. free sulfhydryl groups, while at pH greater than 4, they tend to exist in the form of oxidation. In the same way, when pH = 2, it is difficult to form disulfide bond between mucin and Alg-Cys nanoparticles, so the adsorption rate of mucin decreases, while at pH = 7.4 it is the opposite [34].
Determination of the distribution of infectious viruses in aerosol particles using water-based condensational growth technology and a bacteriophage MS2 model
Published in Aerosol Science and Technology, 2019
Maohua Pan, Leah Carol, John A. Lednicky, Arantzazu Eiguren-Fernandez, Susanne Hering, Z. Hugh Fan, Chang-Yu Wu
The current experimental set-up does not identify where these viruses get deactivated within the system. All processes, including nebulization, transport, classification, and sampling, could lead to the deactivation of the viruses. However, the survivability of MS2 with AS as the suspension media varied with particle size, and the survivability value was relatively larger than the DI water and BES (p < 0.0001); the difference suggests that the protective effect of the AS, mucin in particular, is better than that of BES and DI water (no protection for viruses; p = 1 for DI and BES). One possible reason is the shielding offered by the solid parts of the AS that protects MS2 from deactivation but yet unspecified means or breakage of the virions into subcomponents. For the deactivation of bacteriophage MS2, the most plausible explanation is the loss of viability after exposure to the air-water interface (AWI), where irreversible rearrangement and folding of the viruses’ protein take place (Thompson and Yates 1999; Trouwborst and De Jong 1973; Trouwborst et al. 1974; Zuo et al. 2014). Since MS2 is relatively hydrophobic, it tends to be attracted to the AWI, and that leads to deactivation. The addition of peptone and other components may reduce surface tension, and thus reduce the quantity of MS2 that partition into the AWI (Adams 1948; Trouwborst and De Jong 1972). Different types of mucins exist in saliva, and their functions include protection of oral tissues against dehydration and chemically induced injuries, and they can form aggregates or form complexes with other biomolecules (Bansil and Turner 2006; Veerman et al. 1996). Hence, in the presence of mucin, AS may aggregate, trap, and hydrate more MS2 particles inside the particles, and subsequently reduce exposure to the AWI compared with DI water and BES used as nebulizing media. The low survivability of infectious MS2 at 60 nm might be due to absence of mucin in small particles, as mucin is composed of large glycoprotein molecules that are less likely to exist at small particle sizes.