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Macronutrients
Published in Chuong Pham-Huy, Bruno Pham Huy, Food and Lifestyle in Health and Disease, 2022
Chuong Pham-Huy, Bruno Pham Huy
Proteins are polymers of different amino acids linked together by peptide bonds in the form of long filaments (polypeptide chains). They wrap themselves in a virtually infinite number of spherical or helical forms, which explains the wide variety of functions performed by proteins (36–38, 47). Proteins differ widely in amino acid content. Some amino acids which are in abundance in one protein may be in meagre amounts in others, and may even be lacking in the rest. Tryptophan, for instance, lacks in certain proteins. However, most of the proteins in animal and plant foods contain all the 20 amino acids (36, 38, 47). The proportion of these amino acids varies as a characteristic of a given protein, but all food proteins contain some of each. Collagen, a fibrillar protein that acts like glue between cells, consists of more than one thousand amino acids. Titin or connectin is a giant protein, greater than one µm in length, the largest known protein. It accounts for the passive elasticity of muscles, and consists of more than 25,000 amino acids (1). Titin is known as the largest sarcomeric protein that resides within the heart muscle. Mutations in the titin gene can cause cardiomyopathies, in particular, dilated cardiomyopathy (48). This cardiac disease is characterized by systolic dysfunction and dilation of the left ventricle (48).
Neuroblastoma
Published in Mark Davenport, James D. Geiger, Nigel J. Hall, Steven S. Rothenberg, Operative Pediatric Surgery, 2020
Patients with neuroblastoma usually present with signs and symptoms that reflect the primary site and extent of disease, although localized disease can be asymptomatic. As 75% of neuroblastoma occurs in the abdominal cavity, an abdominal mass detected on physical examination is a common clinical feature, as is the complaint of abdominal pain. Other primary sites of neuroblastoma include the posterior mediastinum (20%), the cervical region (1%), and the pelvis (4%) (organ of Zuckerkandel) (Figure 60.1). Respiratory distress or dysphagia may reflect a thoracic tumor. Altered defecation or urination may be caused by mechanical compression from a pelvic tumor or by spinal cord compression from a paraspinal tumor. Spinal cord compression may also present as an altered gait. A tumor in the neck or upper thorax can produce Horner syndrome (ptosis, miosis, and anhydrosis), enophthalmos, and heterochromia of the iris. Acute cerebellar ataxia has also been observed, characterized by the dancing-eye syndrome, which includes opsoclonus, myoclonus, and chaotic nystagmus. Two-thirds of these cases occur in infants with mediastinal primary tumors. Additional signs and symptoms that reflect excessive catecholamine or vasoactive intestinal polypeptide (VIP) secretion include hypertension, diarrhea and weight loss.
Finding a Target
Published in Nathan Keighley, Miraculous Medicines and the Chemistry of Drug Design, 2020
Amino acids are di-functional, containing a basic amine group and acidic carboxyl group. Each of the 20 amino acids is an alpha-amino acid, in other words, the amine substituent is attached to the alpha carbon next to the carbonyl group. Also note that 19 of those amino acids are primary amino acids and only differ in the side chain substituent. Having both acidic and basic groups, amino acids are able to undergo internal acid-base reactions to produce dipolar ions, called zwitterions at a particular pH, known as the isoelectric point, and are amphoteric, acting as both an acid and a base, which is crucial for their involvement in biological catalysis. A polypeptide is synthesised from amino acids by the condensation reaction between the carboxylic acid group of one amino acid with the amino group of the next to form an amide linkage, or peptide bond, via an enzyme-controlled pathway.
Regenerative responses of rabbit corneal endothelial cells to stimulation by fibroblast growth factor 1 (FGF1) derivatives, TTHX1001 and TTHX1114
Published in Growth Factors, 2021
Jessica Weant, David D. Eveleth, Amuthakannan Subramaniam, Jennifer Jenkins-Eveleth, Michael Blaber, Ling Li, David M. Ornitz, Asaf Alimardanov, Trevor Broadt, Hui Dong, Vinay Vyas, Xiaoyi Yang, Ralph A. Bradshaw
Tissue growth in higher organisms is produced by increases in cell size (hypertrophy) and cell number (hyperplasticity). The stimuli that control and produce these responses are basically external to the cell and include interactions with extracellular matrix, other cells, and soluble factors. Importantly, the ability of cells to respond to these external signals, and the nature of these responses, is dependent on a variety of conditions, e.g. cell cycle status, differentiative state, etc. such that the activation of a pathway in one cell type might lead to proliferation while in another, produce apoptotic cell death. One major element in the regulation of growth events is the polypeptide growth factors which are, for the most part, soluble ligands that are exported from their cells of origin and then interact with target cells through cell surface receptors (Bradshaw and Dennis 2011; Heldin et al. 2014). There are several types of growth factor families based on the kind of receptor they utilise. One of these, the fibroblast growth factor receptor (FGFR) family, is composed of seven members coded by four unique genes (Ornitz et al. 1996; Zhang et al. 2006; Ornitz and Marie 2015) and the associated ligand family of fibroblast growth factors (FGFs) contains 22 members that are subdivided into seven groups.
Elastin-Like Polypeptide Delivers a Notch Inhibitory Peptide to Inhibit Tumor Growth in Combination with Paclitaxel
Published in Journal of Chemotherapy, 2019
Jung Su Ryu, Leslie Robinson, Drazen Raucher
SynB1-ELP1-dnMAML was labeled with Rhodamine (Rho) and administered intravenously to determine the pharmacokinetics. Since a previously published study from our lab has shown that hyperthermia does not induce any significant changes in the elimination rate of Bac-ELP conjugated to the c-myc inhibitory peptide,19 the experiments in this study were performed without heating. The clearance behavior of the polypeptides was well described by a two-compartment pharmacokinetic model. As shown in Figure 2, the polypeptides displayed an initially rapid clearance from the blood, followed by a slower clearance. Importantly, the AUC of SynB1-ELP1-dnMAMAL was 45,562 ± 2,891 µg min mL–1 for 480 min, and its distributional half-life is 24 min, while its terminal half-life is 37.14 min. The other pharmacokinetic parameters are also shown in Table 1.
Rhodotorula glutinis as a living cell liposome to deliver polypeptide drugs in vivo
Published in Drug Delivery, 2019
Zhengbin Fei, Shiyu Li, Jiajia Wang, Yuzhe Wang, Zhenyou Jiang, Wenhua Huang, Hanxiao Sun
At present, polypeptides are known for their low molecular weight and being directly absorbed by humans, which has recently been paid more and more attention. Oral bioactive bacteria capsules containing peptide drugs also highlight its significance in many respects. Protein and peptide drugs are widely distributed in nature and play an important role in the prevention and treatment of diseases. Clinically, many peptide drugs have excellent efficacy, such as erythropoietin (EPO) (Bertolini et al., 2009), granulocyte-macrophage colony stimulating factor (GM-CSF), and interleukin-2 (IL-2), which are mainly used to stimulate hematopoiesis, antitumor effect and other aspects (Moghaddam et al., 2018). For example, insulin can be hydrolyzed and inactivated by proteolytic enzymes in the stomach and duodenum. Our study showed better oral bioavailability for R. glutinis bioactive cell capsules introduced with insulin. Thus, we report that R. glutinis bioactive bacteria ‘capsule’ system may become a new theoretical and application breakthrough for the drug liposomes.