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Biomedical subjects

K Ohlsson

Publications and source records attributed to K Ohlsson.

At least 145 records · Page 8Linked to original sources

Isolation, properties, and complete amino acid sequence of human secretory leukocyte protease inhibitor, a potent inhibitor of leukocyte elastase.

A potent inhibitor of human leukocyte elastase (EC 3.4.21.37) and cathepsin G (EC 3.4.21.20) and of human trypsin (EC 3.4.21.4) has been purified from human parotid secretions. The complete amino acid sequence of this protein has been determined. The sequence suggests that the protein has two domains of about 54 amino acids, each of which contains four disulfide bonds. On the basis of a limited homology to other protease inhibitors, the antielastase and antitrypsin activities are thought to be properties of the C-terminal and N-terminal domains, respectively. The affinity of the inhibitor for leukocyte elastase is very high, suggesting a functional role for the protein in preventing elastase-mediated damage to oral and possibly other mucosal tissues.

Amino Acid Sequence↗

Levels of free granulocyte elastase in bronchial secretions from patients with cystic fibrosis: effect of antimicrobial treatment against Pseudomonas aeruginosa.

Large amounts of free granulocyte elastase (GE), an enzyme capable of mediating airway damage, have been found in bronchial secretions of patients with cystic fibrosis who are infected with Pseudomonas aeruginosa. This finding indicates an imbalance between GE and its antiproteases, alpha 1-proteinase inhibitor (alpha 1-PI) and bronchial mucosal inhibitor (BMI), in the airways of these individuals. The effect of intravenous antimicrobial treatment against P. aeruginosa on activity and concentration of GE, BMI, and alpha 1-PI was evaluated in 30 treatment courses of 20 patients with cystic fibrosis. Although sputum volume and level of immunoreactive GE decreased and concentrations of alpha 1-PI and BMI increased significantly (P less than .05), a high level of free GE persisted. No active alpha 1-PI and BMI were detectable after treatment. High levels of GE correlated with a poor pulmonary condition (rs = .98, P less than .001). In vitro, elastolytic activity of bronchial secretions from patients with cystic fibrosis was significantly inhibited by eglin C and an oxidation-resistant variant of alpha 1-PI, both compounds currently produced by recombinant DNA technology.

Anti-Bacterial Agents↗

Pancreatic endoproteases and pancreatic secretory trypsin inhibitor immunoreactivity in human Paneth cells.

Normal and metaplastic gastrointestinal mucosa obtained at surgical resection were studied by light microscopy, using the unlabelled antibody enzyme method for immunohistochemical staining of lysozyme, pancreatic endoproteases, and pancreatic secretory trypsin inhibitor (PSTI). Paneth cells in the mucosa of normal small intestine, gastric mucosa with intestinal metaplasia, and colonic metaplastic mucosa were found to contain anionic trypsin, cationic trypsin, lysozyme, and PSTI immunoreactivity, but not chymotrypsin and elastase immunoreactivity. Normal gastric and colonic mucosa and some goblet cells in the small intestine showed positive PSTI immunoreactivity but no endoprotease immunoreactivity. The presence of immunoreactive trypsin and immunoreactive PSTI in the Paneth cells, which are of secretory type, probably indicates an important extrapancreatic source of these proteins rather than a storage of endocytosed material.

Adenoma↗

Metabolism of 131I-labelled human pancreatic cationic trypsin after intraduodenal administration.

Human pancreatic cationic trypsin labelled with 131I was administered into the duodenum in 9 healthy individuals. Five had earlier been proctocolectomized and had ileostomies. Radioactivity was measured in plasma, urine, ileostomy content and feces for a period of 72 h. Radioactivity was present in plasma 15 min after administration. The total recovery of radioactivity was 78-98%, the largest amount being observed in urine during the first 24-hour period. About 20% of the administered radioactive dose was recovered in ileostomy content and 10% in feces. The recovered radioactivity in plasma, urine and extracts of ileostomy content and feces was characterized with dialysis and gel filtration. All radioactivity in plasma and urine corresponded to free 131I, whereas in the extracts radioactivity corresponding to intact enzyme and degradation products as well as a small amount of free 131I was observed. It is concluded that pancreatic trypsin is degraded during intestinal passage as with other proteins. Due to a deiodinating mechanism in the intestine, only free 131I is absorbed into the circulation. This deiodination does not take place in duodenal juice. The absence of high molecular weight radioactivity in plasma argues against an enteropancreatic circulation.

Adult↗

Elevated pancreatic secretory trypsin inhibitor levels during severe inflammatory disease, renal insufficiency, and after various surgical procedures.

Elevated levels of immunoreactive pancreatic secretory trypsin inhibitor (PSTI) were found in serum from patients with perforated duodenal ulcer, bacterial peritonitis, urosepticemia, pneumonia, acute renal failure, and also after different surgical procedures. The extent of the trauma seemed to determine the maximal level of PSTI. The increase found paralleled the changes seen in the acute-phase protein antichymotrypsin. There was, however, almost no increase in trypsinogen, thought to be produced together with PSTI in the acinar cells of the pancreas. In conclusion, there is evidence that PSTI is probably also produced somewhere outside the pancreas, in agreement with recent immunohistochemical data. This production may be part of a general acute-phase reaction. Thus, PSTI may have a more general inhibitory function against trypsin-like protease release in tissue injury, instead of being a purely local trypsin inhibitor in the pancreatic gland.

Acute Kidney Injury↗

Protease inhibitors in plasma and faecal extracts from patients with active inflammatory bowel disease.

The level and functional activity of the major protease inhibitors in plasma and faecal extracts were analysed in 26 consecutive patients admitted during their first attack of acute severe colitis. The patients were retrospectively divided into two groups: one with total colitis and another with distal colitis. The patients with total colitis had a significantly lower alpha 2-macroglobulin level in plasma than normal individuals and patients with distal disease, whereas no difference in the levels of alpha 1-protease inhibitor, antichymotrypsin, antithrombin III, and alpha 2-antiplasmin was noted between the two groups. The protease-inhibiting capacity was saturated, and free proteolytic activity was present in the faecal extracts. In the extracts complex formation was demonstrated between leukocyte proteases and the antiproteases alpha 1-protease inhibitor and alpha 2-macroglobulin. It is concluded that the low plasma level of alpha 2-macroglobulin in patients with severe total colitis is mainly due to a consumption caused by complex formation with proteases, as earlier demonstrated in patients with acute pancreatitis and sepsis.

Adult↗

Leukocyte elastase alpha 1-proteinase inhibitor complexes may diagnose pancreatic abscesses early.

Complexes of alpha 1-proteinase inhibitor and leukocyte elastase could be demonstrated by crossed immunoelectrophoresis of the peritoneal fluid from four patients who developed a pancreatic abscess during an attack of pancreatitis. No such complexes were seen in 69 patients with acute pancreatitis without an abscess. The complexes were demonstrable 2-3 days before the abscess was clinically evident. They may thus be diagnostically and therapeutically important. The appearance of these complexes denotes the liberation of large amounts of leukocyte elastase. This may help explain the pathophysiology and high mortality of the pancreatic abscess, since leukocyte elastase is known to cause degradation of all components of connective tissue and also degradation and activation of many components within the different cascade systems.

Abscess↗

Protease-antiprotease imbalance, hemodynamic and regional blood flow changes in experimental pancreatitis.

Pathologic proteolysis in pancreatitis is an important clue to understand the pathophysiology in pancreatitis. Impairment of pancreatic circulation is also important in the development of severe pancreatitis. In an attempt to study some of the biochemical and circulatory events in experimental pancreatitis in the pig the following experiments were undertaken. Pancreatic and splanchnic blood flow were studied in severe and mild pancreatitis with the microsphere method, together with cardiac output and mean arterial pressure. Kininogen, alpha-2-macroglobulin and alpha-1-proteinase inhibitor were measured in plasma and in peritoneal fluid. In severe pancreatitis consumption of kininogen in the peritoneal cavity was demonstrated together with a final lowering of the plasma protease inhibitors. This was accompanied by a rapid reduction of cardiac output and finally mean arterial blood pressure. Pancreatic blood flow was profoundly diminished in this group. No such changes were found in mild pancreatitis. It is concluded that pancreatic ischemia in pancreatitis is associated with protease-antiprotease imbalance.

Animals↗

Influence of the human pancreatic secretory trypsin inhibitor on trypsin-induced C3 and kininogen cleavage: an in vitro study.

Cleavage of C3 and kininogen in human plasma following the addition of increasing amounts of human cationic trypsin was studied using an in vitro model. The cleavage was correlated to the degree of saturation of the plasma protease inhibitors alpha 2-macroglobulin and alpha 1-proteinase inhibitor, and also with varying amounts of human pancreatic secretory trypsin inhibitor. When alpha 2-macroglobulin reached about 70% saturation, there was a prompt cleavage of most of the C3 and kininogen in spite of the presence of 90% free alpha 1-proteinase inhibitor. The consumption of alpha 1-proteinase inhibitor decreased with increasing concentrations of the pancreatic secretory trypsin inhibitor. This inhibitor was needed in a concentration of about 10 mumol to block trypsin-induced C3 and kininogen cleavage completely. As trypsin is thought to be the key trigger enzyme of the pathophysiological changes in acute pancreatitis, it seems reasonable to propose that the pancreatic secretory trypsin inhibitor might be of therapeutic interest in severe acute pancreatitis provided large enough amounts can be made available.

Complement Activation↗

Characterization of radioactivity in plasma after intraduodenal administration of 131I-labelled human cationic trypsin.

Active human pancreatic cationic trypsin labelled with 131I was administered into the duodenum in nine healthy individuals pretreated with "cold", i.e. non-radioactive iodine. Radioactivity in plasma was measured during 72 hours and was present in plasma after 15 minutes with a maximum 1 hour after administration. The recovered radioactivity in plasma was characterized using dialysis and gel-filtration and the radioactive iodine was found to be in the form of free 131I. Our results are in agreement with recent experimental studies indicating the presence of de-iodinases in the intestine. Furthermore, it was found that pretreatment with "cold" iodine prevented isotope binding to circulating plasma proteins.

Adult↗

Early diagnosis of a pancreatic abscess in acute pancreatitis.

Complexes of alpha 1-proteinase inhibitor and leukocyte elastase could be demonstrated on crossed immunoelectrophoresis of the peritoneal fluid in 4 patients, who developed a pancreatic abscess during an attack of acute pancreatitis. No such complexes were seen in 69 patients with acute pancreatitis without an abscess. The complexes were demonstrable 2-3 days before the abscess was clinically evident. They may thus be diagnostically and therapeutically important.

Abscess↗

Disseminated intravascular coagulation and antiprotease activity in acute human pancreatitis.

The coagulation and fibrinolytic systems were analysed parallel to the clinical evaluation in 27 attacks of acute human pancreatitis of different severity. Consumptive coagulopathy was evident from decreased platelet counts, decreased prothrombin values and consumption of fibrinogen during the first days in severe attacks. Fibrinolysis was suggested by decreased plasminogen values and the presence of fibrinogen degradation products. All main protease inhibitors of the two systems showed protease-antiprotease complexation and lower functional than quantitative values. Functional levels of the protease inhibitors were almost zero in the peritoneal fluid in severe attacks. It is concluded that severe acute pancreatitis results in consumptive coagulopathy and fibrinolysis together with a local antiprotease deficiency. All the changes are closely correlated to the severity of the disease.

Acute Disease↗

Immunohistochemical demonstration of pancreatic secretory proteins in human paneth cells.

Gastro-intestinal mucosa obtained at surgical resection was studied by light microscopy using the unlabelled antibody enzyme method for immunohistochemical staining of lysozyme, anionic trypsin, cationic trypsin and pancreatic trypsin inhibitor (PSTI). Paneth cells, identified by their content of lysozyme, contained anionic trypsin, cationic trypsin and PSTI-like immunoreactivity. The demonstration of immunoreactive trypsin and immunoreactive PSTI is a further indication of the resemblance between Paneth cells and the pancreatic acinar cells.

Epithelial Cells↗

Correlation among complement activation, protease inhibitors, and clinical course in acute pancreatitis in man.

Changes in complement levels and protease inhibitors were measured in plasma/serum and peritoneal fluid during 15 attacks of acute pancreatitis. The abnormalities found in the complement system and the protease inhibitors were most pronounced in severe attacks, especially in the peritoneal fluid. Depressed levels of C1q, C3, properdin, and factor I were found in blood on admission in severe attacks. A decrease during the first days of illness was found for C1q, C3, C4, properdin, factor I, and factor H levels in blood. There was a discrepancy between the low C1q and the high C1r and C1s levels in blood. Complexes of C1r-C1s-C1 inactivator and factor B conversion products were found, especially in the peritoneal fluid, denoting an activation of the complement system. High levels of trypsin in complex with alpha 1-protease inhibitor were found, both in blood and in peritoneal fluid, denoting the liberation of active trypsin in acute pancreatitis. The levels of the functional alpha 2-macroglobulin were low, especially in the peritoneal fluid. It is concluded that both classical and alternative complement activation take place in acute pancreatitis, starting in the peritoneal cavity. The magnitude of activation depends on the severity of the disease. Trypsin-induced activation of complement components may explain some of these changes.

Acute Disease↗

Elimination of protease-inhibitor complexes from the arthritic joint.

In the rheumatic joint, destructive proteolytic enzymes are released and counteracted by complexation to the predominant inhibitors alpha 2-macroglobulin and alpha 1-antitrypsin. The articular elimination of these complexes is thought to be of decisive importance in the protease-inhibitor interplay influencing the inhibitory capacity of the synovial fluid. Protease-alpha 2-macroglobulin complexes showed an intraarticular half-life shorter than 2 hours in arthritis and were eliminated by various routes including phagocytosis in cells of the synovial membrane and in regional lymph nodes, in addition to haematogenous resorption and uptake in the liver. The phagocytosed complexes were degraded to low-molecular-weight metabolites excretable in the urine. The articular elimination of elastase-alpha 1-antitrypsin complexes seemed to be an equivalent process, but an additional intrasynovial dissociation of the complexes was also indicated. Thus the intraarticularly released elastase seemed to be bound and eliminated in complex with alpha 2-macroglobulin.

Animals↗

Antileukoprotease in patients with maxillary sinusitis.

Antileukoprotease, an inhibitor of leukocyte elastase, was studied in paired sera from 12 patients with maxillary sinusitis. The serum concentration of antileukoprotease was increased at the day of admission to hospital, compared with the serum concentration in convalescence sera. In purulent maxillary sinus secretions antileukoprotease was found in complex with leukocyte elastase, as shown by gel filtration. The findings suggest a local protective function of antileukoprotease in maxillary sinus.

Humans↗