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The patient with acute gastrointestinal problems
Published in Peate Ian, Dutton Helen, Acute Nursing Care, 2020
Rebecca Maindonald, Adrian Jugdoyal
The pancreas is a retroperitoneal gland approximately 12–15cm long and 2.5cm thick. It is connected by the pancreatic duct to the common bile duct, which in turn empties into the duodenum. Structurally, the pancreas is composed of clustered epithelial cells, about 99% of which constitute the exocrine portion of the organ. They secrete approximately 1200–1500mL daily of pancreatic juice, consisting of water, salts, sodium bicarbonate and enzymes. Bicarbonate pancreatic juice mixes with acidic chyme in the duodenum to neutralise the substance. Pancreatic juices consist of several enzymes that aid in the digestion of carbohydrates, proteins and fats. The protein digesting enzymes are secreted initially within the pancreas in an inactive form (trypsinogen), as the active form would damage the pancreas itself. Trypsinogen is only activated when it reaches the duodenum and mixes with other enzymes. It is the premature activation of trypsinogen, when it is still in the pancreas, which causes serious problems (pancreatitis). The remaining 1% of the cells are organised into pancreatic islets (islets of Langerhans), which have an endocrine function. These cells secrete hormones such as glucagon, insulin, somatostatin and pancreatic polypeptide (see section on diabetic emergencies in Chapter 11).
Chronic Pancreatitis: Small Duct Disease with Uncontrolled Pain
Published in Savio George Barreto, Shailesh V. Shrikhande, Dilemmas in Abdominal Surgery, 2020
Michael F. Nentwich, Jakob R. Izbicki
Serum trypsinogen: Widely available. Serum trypsinogen levels correlate with pancreatic acinar mass and has a high sensitivity in advanced pancreatic insufficiency. In earlier stages of pancreatic insufficiency, the test is not as sensitive and serum trypsinogen levels rise in abdominal pain of non-pancreatic origin as well as in acute pancreatitis.
Hereditary Pancreatitis
Published in Dongyou Liu, Handbook of Tumor Syndromes, 2020
The PRSS1 gene on chromosome 7q34 spans 12.8 kb and encodes a 247 aa, 26.5 kDa cationic trypsinogen (or trypsinogen-1, an inactive form of trypsin), which is a member of the trypsin family of serine proteases. Secreted by the pancreas, trypsinogen is cleaved of an eight-amino-acid trypsinogen activation peptide (TAP) by enterokinase to form active trypsin in the small intestine. TAP may be also cleaved by trypsin in the presence of calcium and association with a binding site formed in the activation region. The resultant active (mature) trypsin is an endopeptidase that cleaves peptide chains following a lysine or arginine, and converts inactive zymogens produced by the pancreas into active digestive enzymes in the duodenum upon food exposure. A second calcium-binding site in trypsinogen as well as trypsin may be occupied by calcium, which prevents trypsin degradation by trypsin on the autolysis site (Arg-122), and by chymotrypsin C (CTRC) at Leu-81 within the calcium binding site [9].
Recent advances in proteolytic stability for peptide, protein, and antibody drug discovery
Published in Expert Opinion on Drug Discovery, 2021
Xianyin Lai, Jason Tang, Mohamed E.H. ElSayed
The pancreas produces trypsinogen, an inactive precursor of trypsin. Trypsinogen is then secreted into the duodenum through the pancreatic duct. Once in the small intestine, the trypsinogen is activated by the enzyme enteropeptidase via proteolytic cleavage [54,55]. Trypsin is an endopeptidase and breaks peptide bonds down via a serine catalysis mechanism at an optimal pH of 7.5–8.5 [56]. The salmon calcitonin is a small peptide of 32 amino acids with a molecular weight of 3,432 Da and is a more potent analog of human calcitonin [57]. The salmon calcitonin was incubated with 0.5 μM trypsin in a sodium acetate (50 mM) buffer and it was completely degraded in 15 min [58]. The human granulocyte colony stimulating factor (G-CSF) is a major cytokine regulator of neutrophilic granulocytes and is able to stimulate the growth of neutrophil colonies from human bone marrow progenitor cells with a molecular weight of about 30,000 Da [59]. The incubation of 100 ug/ml of G-CSF with 1 ug/ml of trypsin revealed that G-CSF was susceptible to trypsin digestion and had about 30% intact protein at 4 h incubation [60].
Trypsinogen and chymotrypsinogen: potent anti-tumor agents
Published in Expert Opinion on Biological Therapy, 2021
Aitor González-Titos, Pablo Hernández-Camarero, Shivan Barungi, Juan Antonio Marchal, Julian Kenyon, Macarena Perán
The pancreas plays a very important role in the digestive function through the secretion of several enzymes necessary for the degradation of nutrients. These enzymes are secreted by acinar cells as zymogens (inactive forms also known as (pro)enzymes) [3]. Once secreted, they are transferred to the small intestine where they are activated. The most studied zymogens are Trypsinogen and Chymotrypsinogen. In the case of Trypsinogen, it is activated to Trypsin in the small intestine by enterokinase. Once activated, it is capable of activating the rest of the pancreatic zymogens, including Chymotrypsinogen into Chymotrypsin [4]. A failure in the production of these proteins can cause poor absorption of nutrients, the most common diseases that lead to exocrine pancreatic insufficiency are chronic pancreatitis and cystic fibrosis [5].
Dramatic increase in serum trypsinogens, SPINK1 and hCGβ in aortic surgery patients after hypothermic circulatory arrest
Published in Scandinavian Journal of Clinical and Laboratory Investigation, 2020
Juhani A. Stewart, Riitta Koistinen, Anna Lempiäinen, Kristina Hotakainen, Ulla-Stina Salminen, Anne Vakkuri, Johanna Wennervirta, Ulf-Håkan Stenman, Hannu Koistinen
Significantly increased concentrations of trypsinogen-1, -2 and -3, trypsin-2–API, SPINK1 and hCGβ were observed in patients after HCA (Figure 1, Table 1). In all patients, the SPINK1 concentrations increased rapidly after the first day, reaching concentrations exceeding the upper reference limit 17-fold on average and in two patients (12%) over 50-fold. The concentrations remained increased until the end of follow-up at 8−10 d. Trypsinogen-1 and -3 concentrations peaked 1 d after HCA, after which they normalized within one day and started again to rise in 13 (76%) and 10 (59%) cases, respectively, exceeding the levels observed on day one. The concentrations of trypsinogen-2 and trypsin-2–API complex showed a similar pattern, although the peak on day one was less pronounced, if found at all. The hCGβ levels also increased, but mostly only after day three, when the hCG levels tend to decrease. These changes were accompanied by increased concentrations of S100β and NSE one day after HCA. Often the S100β and NSE levels normalized within a week after HCA. In all but one patient amylase levels also increased. However, in 11 (65%) patients this happened only 2 d after the operation or later. Serum CRP levels before and 3 d after the operation were available from ten patients (59%) and indicate a dramatic increase from 7.5 (3.0–60) to 226 (140–303) mg/l (p = .005).