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StomachGastric Secretions, Motility, Digestion and Vomiting
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
The contents of the stomach, at a pH<2 and with proteolytic enzymes, can damage its mucosal lining. Mucus, a sticky and viscous mixture of mucoproteins and mucopolysaccharides, provides a major part of protection against auto-digestion. It adheres to the luminal cells, forming a layer up to 200 μm thick, and protects the stomach wall against mechanical and chemical damage. The mucin molecule has abundant basic side chains which can react with H+ ions which diffuse into it. Further protection is provided by HCO3− secreted by the surface epithelial cells of the stomach. As H+ ions diffuse into the mucus they react with HCO3− to produce CO2, and so the mucus pH does not fall and is maintained close to 7.0. The surface cells and the mucus are therefore protected against pepsins which only work at a pH <5.0. Mucus and HCO3− secretion by the surface epithelial cells are continuously renewed. Prostaglandins which increase production of mucus and HCO3− are produced locally to promote healing and provide added protection.
Methods in Experimental Pathology of the Pleura
Published in Joan Gil, Models of Lung Disease, 2020
No specific fixatives have been favored for the mesothelial cell study. For most light microscopic (LM) studies, 4% formaldehyde in phosphate or other appropriately buffered solutions at neutral pH are adequate. For transmission and scanning electron microscopy (TEM, SEM), 3% glutaraldehyde in 0.1 N sodium cacodylate or similar fixatives appears to be satisfactory. To preserve mucoproteins containing hyaluronic acid, fixative in 100% alcohol or other nonaquous solvents are used. Depending on the investigator’s other aims, such as immuno-histochemistry, fixatives specifically designed to preserve the desired antigens or quick freezing followed by freeze-substitution or freeze-drying can be used.
The Urinary System and Its Disorders
Published in Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss, Understanding Medical Terms, 2020
Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss
The most frequently performed laboratory test related to the urinary system is a urinalysis (UA). Urinalysis usually includes qualitative evaluation for the presence of protein, glucose, ketones, and blood and determination of urinary pH and osmolarity. Further, microscopic examination of the urinary sediment is an essential component of a UA and allows detection of crystals, cells, and a variety of casts (mucoprotein masses that may entrap cellular components or fat droplets). Casts are identified by their components and may aid diagnosis. For example, RBC casts contain red blood cells indicating glomerulonephritis, WBC casts include white blood cells suggestive of pyelonephritis or several other disorders, and bacterial casts are diagnostic of bacterial pyelonephritis. Urinary infections may be diagnosed by culture and sensitivity (C&S), which is often performed in relation to a UA.
Neutrophil Extracellular Trapping Network Promotes the Pathogenesis of Neutrophil-associated Asthma through Macrophages
Published in Immunological Investigations, 2021
Xi Chen, Yuanyuan Li, Ling Qin, Ruoxi He, Chengping Hu
Currently, DNase I degradation of NETs and inhibition of the formation of NETs are widely used in studies on the effects and mechanism of NETs. Clinically, DNase I has also been used in the treatment of cystic fibrosis (Khan et al. 2019). Besides, DNase I has shown some relief effects in both severe and ordinary asthma (Boogaard et al. 2008; Silverman et al. 2012). Herein, inhaled DNase I by NA mice (NA/DNase I group) also improved NA symptoms, as manifested as reduced inflammatory cells infiltration around the bronchi, reduced airway resistance, and rescued lung dynamic compliance. Considering that DNase I significantly reduced the formation of NETs and free dsDNA abundance, we speculate that DNase I improve NA symptoms through degrading NETs and extracellular DNA. Besides, hypersecretion of mucus is another important pathophysiological feature of NA. Excessive mucus is likely to lead to airway resistance and impaired lung function in NA patients (Gao et al. 2017). As evidenced by PAS staining, airway goblet cell metaplasia, mucous secretion, and the formation of mucus plugs were observed in the lung sections of NA mice. Moreover, two mucoproteins, MUC5ac and MUC5b, were significantly increased in NA mice lung and decreased by DNase I treatment. MUC5ac and MUC5b are major mucin components, and MUC5ac is recognized as a specific marker of airway goblet cells (Bonser and Erle 2017). Thus, these findings indicate that NETs could promote the hypersecretion of mucus during NA, while DNase I could reduce the secretion of mucus by inhibiting the generation of NETs.
Bioadhesive polymer/lipid hybrid nanoparticles as oral delivery system of raloxifene with enhancive intestinal retention and bioavailability
Published in Drug Delivery, 2021
Xinhui Du, Na Gao, Xiaoyong Song
In the formulation, glyceryl distearate (Precirol ATO 5) serves as a lipid matrix, Carbopol 940 functions as a bioadhesive material, and TGPS plays the role of apportion-promoting enhancer. These three materials were adopted on purpose to construct bioadhesive nanocarrier based on their respective functions. ATO 5 is a solid lipid above the body temperature that can guarantee high drug entrapment and sustained drug release (Xing et al., 2018). Carbomers with a brand name Carbopol, are synthetic macromolecular polymers based on acrylic acid that are crosslinked with either allyl sucrose or allyl ethers of pentaerythritol. Upon contact with liquid, carbomers become hydrated and swelling, and can interact with mucoproteins in the mucus and adhere to the mucosa (Chawla & Saraf, 2012), thus providing bioadhesion. TPGS is a versatile biomaterial that can be used as emulsifier, drug solubilizer, absorption enhancer, and as a modifier for lipid-based drug delivery systems (Yang et al., 2018). In this study, we integrated these functional materials into the formulation of nanoparticles in an attempt to collaboratively enhance the oral delivery efficacy.
Adventitial cystic disease of the popliteal artery
Published in Baylor University Medical Center Proceedings, 2019
Rachel Rendon, Kristyn Mannoia, William Shutze
Adventitial cystic disease (ACD) is a rare vascular disorder characterized by fluid accumulation in the adventitial layer of a vessel, which may cause luminal narrowing or even complete occlusion.1,2 The cystic fluid has been described as gelatinous or mucoid in consistency, with a high content of hyaluronic acid and different combinations of mucopolysaccharides and mucoproteins.1,3 Symptoms of ACD depend on the location of the cyst, with the popliteal artery being the most common vessel affected.3 When the popliteal artery is affected, the most common presenting symptom is intermittent claudication that is usually acute in onset and of longer duration than claudication associated with atherosclerosis.1–3 We present two cases of cystic adventitial disease of the popliteal artery.