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Arsenals of Pharmacotherapeutically Active Proteins and Peptides: Old Wine in a New Bottle
Published in Debarshi Kar Mahapatra, Swati Gokul Talele, Tatiana G. Volova, A. K. Haghi, Biologically Active Natural Products, 2020
Diabetes mellitus (DM) results because of increased concentration of glucose in blood [145]. DM is characterized by hyperglycemia, glycosuria, ketonemia, ketonuria, polyuria, nocturia, polydipsia, polyphagia, and asthenia. There are two types of DM: Type I DM (insulin-dependent DM) resulting due to destruction of β cells of islets of Langerhans. Thus very little or no insulin is produced by the body.Type II DM (Noninsulin dependent DM) resulting due to failure of recognition of insulin by the insulin receptors arising because of insulin resistance [1].
Yeast as Source for Therapeutic and Diagnostic Proteins
Published in Yoshikatsu Murooka, Tadayuki Imanaka, Recombinant Microbes for Industrial and Agricultural Applications, 2020
Annie De Baetselier-Van Broekhoven
The biosynthesis of insulin is carried out in the β-cells of the islets of Langerhans located in the pancreas. Human insulin is initially produced as a preproprotein with the following configuration: signal peptide-B-Arg-Arg-C-Lys-Arg-A, where C is a peptide of 32 amino acids and A and B are the A and B chain of human proinsulin, respectively [30]. Preproinsulin is converted to proinsulin by subsequent cleavage of the signal peptide and formation of three disulfide bridges. These disulfide bridges connect amino acid residue 7 in the A chains to amino acid residue 7 in the B chain, A-20 to B-19, and A-6 to A-ll. Proinsulin is further processed by enzymatic cleavage at the two dibasic sequences, thereby removing the C chain [31,32]. The resulting molecule, mature insulin, contains the B and A chains linked together by two disulfide bridges.
Microencapsulation of Living Cells and Tissues — Theory and Practice
Published in Franklin Lim, Biomedical Applications of Microencapsulation, 2019
A new and unique microencapsulation process for enclosing viable cells, tissues, and other labile biological substances within a semipermeable membrane was successfully developed by Lim in 1978.1 Preliminary in vitro studies of several types of microencapsulated cells and tissues such as red blood cells (RBC), sperm cells, hepatoma cells, hepatocytes, pancreatic endocrine tissues, and islets were described by Lim and Moss2 in 1979. The first in vivo application of this novel technique to diabetes research wherein the implantation of microencapsulated islets of Langerhans resulted in the sustained normalization of diabetic conditions in experimental animals was reported by Lim and Sun in 1980.3 New in vitro applications and both in vivo and in vitro follow-up studies of microencapsulated cells have been reported recently.4-6
Dietary ingestion of 2-aminoanthracene (2AA) and the risk for type-1 diabetes (T1D)
Published in Journal of Environmental Science and Health, Part A, 2020
Isaiah Seise, Zachary A. Pilz, Moses Yeboah Kusi, Bethany Bogan, Brittany Jean McHale, Worlanyo E. Gato
Another index of diabetes is hyperglycemia. Hyperglycemia can be used to assess the malfunction or destruction of insulin-producing β-cell.[10] A chemical substance can be identified as a toxin to pancreatic β-cell by hyperglycemia.[13] At week 6, blood glucose levels did not show a regular trend in all three groups. However, at week 12, the treated groups seem to show high glucose concentration in the blood. The lack of regular variation in blood glucose levels at week 6 may indicate that the full effects of 2AA have not been set forth. Also, T1D develops in stages, so the glucose concentrations can fluctuate during the progress of the disease.[10] The high levels of blood glucose in the treated groups at week 12 is suggestive of low production of insulin in the pancreas due to destruction or malfunction of the β-cells resulting from the ingestion of 2AA contaminated diets. On the other hand, a larger size of islets of Langerhans was observed in the pancreas of rats in the high dose treatment group. A previous study on the toxic effects of 2-aminoanthracene ingestion in pregnant Sprague Dawley dams in our laboratory showed increased sizes of the pancreatic islets with increasing dose of 2AA. The islets of Langerhans are the main sites for β-cells which produce insulin to regulate glucose levels in the blood stream.[14] It is worth stating that an increase in the number of insulin-producing β-cells could possibly lead to an enlargement in the sizes of islets.[15] The increase in size of islet cells in the pancreas of rats in the high dose group without a corresponding efficiency in the processing of blood glucose, which is demonstrated by elevated glucose concentration could be an indication of β-cell malfunction. An increase in the number of β-cells and for that matter the size of islet cells should have eventually reflected in uptake of glucose into cells for metabolic processes. A study by Kilimnik et al in 2012 reported changes in endocrine cell mass in large islets of patients of Type 2 diabetes.[16]