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B Sternby

Publications and source records attributed to B Sternby.

53 records · Page 3Linked to original sources
PubMed1989

Carboxyl ester lipase in human tissues and in acute pancreatitis.

Carboxyl ester lipase was purified from human pancreatic juice. Antisera were raised in rabbits and the monospecificity of the antibody was verified by immunoblotting. The enzyme was present in zymogen granules of acinar cells, in occasional duct cells, and in secretory material in normal pancreas in immunohistochemistry. Also, occasional cells in the epithelium of small intestinal villi but not the granules of Paneth cells, were stained. Decreased and evenly dispersed staining was observed in necrotic acinar cells in acute pancreatitis, whereas the reaction was intensive in plugs in acinar lumina. Interstitial staining was seen around necrotic pancreatic lobules and in areas of fat necrosis. This staining pattern is similar to that obtained with antisera against other lipolytic pancreatic proteins, but differed from that with antisera against trypsin and pancreatic secretory trypsin inhibitor. We conclude that carboxyl ester lipase behaves similarly to the other lipolytic enzymes during acute pancreatitis and that interstitial localization of secretory lipolytic enzymes is characteristic of the necrotizing inflammatory process in pancreas.

Acute Disease↗
PubMed1988

Concerted action of human carboxyl ester lipase and pancreatic lipase during lipid digestion in vitro: importance of the physicochemical state of the substrate.

The pancreatic enzyme carboxyl ester lipase (CEL) has been shown to hydrolyse a large number of different esters, including triacylglycerols, cholesteryl esters and retinyl esters with an absolute requirement for bile salts. Some of the lipids that are substrates for CEL can also be hydrolysed by pancreatic lipase. In order to investigate the relative roles of human CEL and pancreatic lipase, the two enzymes were incubated on a pH-stat with isotope-labelled lipid substrate mixtures in physicochemical forms resembling the state of the dietary lipids in human intestinal contents. In the first set of experiments, cholesteryl oleate (CO) and retinyl palmitate (RP) were solubilised in an emulsion of triolein (TO) stabilised by egg phosphatidylcholine and bile salts. Lipase (always added together with its cofactor, colipase) hydrolysed TO, with monoolein and oleic acid as end-products, whereas CEL alone could not hydrolyse TO in the presence of phosphatidylcholine (PC). Lipase alone did not hydrolyse CO or RP, but CEL did hydrolyse these esters if lipase was present. Release of [3H]glycerol from labelled TO increased only slightly if CEL was added compared to lipase alone, suggesting that monoolein hydrolysis was slow under these conditions. In the second set of experiments, CO and RP were dissolved in bile salt/monoolein/oleic acid dispersions with varying bile salt concentrations. CEL hydrolysed CO and RP more rapidly in a system with a high bile salt concentration containing mixed micelles than in a system with a low bile salt concentration, where the lipids were dispersed in the form of mixed micellar and non-micellar aggregates; both types of aggregate have been reported to exist in human intestinal contents. In conclusion, these data suggest that the main function of CEL under physiological conditions is to hydrolyse cholesteryl and retinyl esters, provided that the triacylglycerol oil phase is hydrolysed by pancreatic lipase, which probably causes a transfer of the substrate lipids of CEL from the oil emulsion phase to an aqueous bile salt/lipolytic product phase. Depending on the bile salt/lipolytic product ratio, the substrate will reside in either micellar or non-micellar lipid aggregates, of which the micellar state is preferred by CEL.

Bile Acids and Salts↗
PubMed1988

Pathogenesis of hypotension in septic shock: correlation of circulating phospholipase A2 levels with circulatory collapse.

Circulating phospholipase A2 (PLA2) has been recognized as a mediator of circulatory collapse in experimental endotoxic shock. To assess the role of serum PLA2 in septic shock in man, we determined serum PLA2 profiles in a prospective study in 12 patients with septic shock. During the hypotensive phase of sepsis, serum PLA2 levels were consistently elevated as high as 33,428 U/ml (normal range 115 +/- 12 [SE]; n = 101). In all 12 patients, PLA2 levels correlated directly with the magnitude and duration of circulatory collapse (p less than .001), with a progressive fall of serum PLA2 levels during convalescence. In contrast, serum PLA2 levels in patients with cardiogenic shock secondary to myocardial infarction remained low. In pancreatitis, PLA2 levels paralleled fluctuations of serum amylase and lipase, whereas in septic shock without pancreatic involvement, PLA2 changes were discordant with changes in pancreatic enzymes. As well, septic shock serum PLA2 failed to crossreact by radioimmunoassay with antiserum against human pancreatic PLA2. These data are consistent with an extrapancreatic source of intravascular PLA2 release during sepsis. Since endogenous serum PLA2 levels correlate directly with the magnitude of hypotension in both experimental endotoxic shock and clinical septic shock, and since parenteral administration of purified exogenous PLA2 reproduces hypotension in experimental models, we conclude that high levels of intravascular PLA2 may contribute similarly to the circulatory collapse in septic shock in man.

Adult↗
PubMed1988

Serum phospholipase A2 correlates with disease activity in rheumatoid arthritis.

We previously demonstrated a marked elevation of the proinflammatory enzyme phospholipase A2 (PLA2) in all synovial fluids and some sera of patients with rheumatoid arthritis (RA). Since PLA2 was found to induce inflammatory changes in the skin and joints of experimental animals, we tested whether the serum level of PLA2 correlates with the clinical activity of RA. In the group of 51 patients with classical or definite RA, 13 (25%) had high serum levels of PLA2 (over 2 standard deviations above the normal mean). Comparison of clinical disease activity in patients with high levels of PLA2 with those with normal PLA2 levels showed that patients with high PLA2 levels had a significantly higher joint count, more swollen joints, much higher Landsbury index, lower functional class, lower hemoglobin, lymphopenia and higher erythrocyte sedimentation rate (ESR). To more accurately assess the relationship between the PLA2 level and disease activity in RA, we formulated 2 indices. Clinical index consisted of the Landsbury index, number of swollen joints and duration of morning stiffness. Laboratory index consisted of hemoglobin, absolute number of peripheral blood lymphocytes, platelet count and ESR. Our results showed that both indices correlated strongly with PLA2 activity (p less than 0.0001). The results support the hypothesis that PLA2 plays a pathogenetic role in RA and suggest that serum PLA2 levels may serve as an additional measure of disease activity.

Adult↗
PubMed1986

Purification of a soluble phospholipase A2 from synovial fluid in rheumatoid arthritis.

A soluble phospholipase A2 (PLA2) was purified 4,500-fold from human rheumatoid synovial fluid. Preparative sodium dodecyl sulfate polyacrylamide gel electrophoresis yielded two bands of PLA2 activity of molecular weights 15,000 and 17,000 and pl 4.2-5.0. Purified PLA2 had absolute 2-acyl specificity, and hydrolyzed phosphatidylcholine with optimal activity at pH 7.5-8.0 and phosphatidylethanolamine with optimal activity at pH 7.0. Human synovial fluid PLA2 did not cross-react with anti-human pancreatic PLA2, as tested by radioimmunoassay.

Arthritis, Rheumatoid↗
PubMed1986

Fat necrosis in human acute pancreatitis. An immunohistological study.

Localization of phospholipase A2, lipase and colipase immunoreactivity were studied in paraffin embedded tissue sections. The samples were taken from the pancreas of 12 patients suffering from acute haemorrhagic necrotizing pancreatitis, and from diseased adipose tissue of 7 patients suffering from traumatic mammary fat necrosis. Peroxidase-antiperoxidase immunohistology revealed consistent positive reaction against phospholipase A2, lipase and colipase at the border of fat necrosis in pancreatic interlobular adipose tissue and in peripancreatic, mesenterial and retroperitoneal fat. The fat necroses of the breast were devoid of reaction. The results support the idea that in addition to lipase colipase and phospholipase A2 participate in the development of fat necrosis in acute pancreatitis. Pancreatic lipolytic enzymes are not present in the adipose tissue in mammary fat necrosis.

Adipose Tissue↗
PubMed1985

The interaction between human pancreatic carboxylester hydrolase (bile-salt-stimulated lipase of human milk) and lactoferrin.

An interaction between lactoferrin and human pancreatic carboxylester hydrolase (carboxylic-ester hydrolase, EC 3.1.1.1) (of bile-salt-stimulated lipase from human milk) has been demonstrated using partition in an aqueous two-phase system. This binding was strongly increased by the presence of sodium taurocholate, giving an apparent dissociation constant of around 10(-7) M. With this constant, significant binding is expected to occur in the intestine of the newborn being breast-fed between lactoferrin and either the pancreatic carboxylester hydrolase or the milk bile-salt-stimulated lipase. For carboxylester hydrolase, the interaction with lactoferrin meant a 1.4-fold increase in hydrolytic activity against p-nitrophenylacetate and cholesterololeate. For the function of lactoferrin we have not studied the importance of this interaction.

Bile Acids and Salts↗
PubMed1984

Purification and characterization of pancreatic colipase from the dogfish (Squalus acanthius).

Pure colipase from dogfish (Squalus acanthius) was obtained from an extract of pancreatic gland. It has a high isoelectric point (10.2) and the molecular weight was calculated to be 9108-9383. The N-terminal sequence was shown to be Gly-Leu-Phe-Leu-Asn-Leu-Ser-Ala-Gly-Glu-Leu-Cys-Val-Gly-Ser-Phe-Gln -Cys-Lys-Ser-Ser-Cys-Cys-Gln-Arg-Glu-Thr-Gly-Leu-Ser-Leu-Ala -Arg-Cys-Ala-. This sequence shows great homology with colipases from man, horse, pig and hen. There were indications of the existence of a proform of dogfish colipase. The propeptide was found to be Ala-Pro-Glu-Arg.

Amino Acid Sequence↗
PubMed1984

Immunoreactive pancreatic colipase, lipase and phospholipase A2 in human plasma and urine from healthy individuals.

A radioimmunoassay for each of the human pancreatic proteins (colipase, lipase and phospholipase A2) is described. Determinations of the mean concentration of each protein in plasma and urine from healthy individuals were carried out with the radioimmunoassays. The values obtained in plasma were 0.5 nM (5.3 micrograms/l), 0.6 nM (32 micrograms/l) and 0.3 nM (4.3 micrograms/l) for colipase, lipase and phospholipase A2, respectively. In urine, the corresponding values were found to be 0.2 nM (2.4 micrograms/l), 0.09 nM (4.4 micrograms/l) and less than 0.017 nM (0.2 micrograms/l). No physical interaction between any of the three proteins and the lipid particles of plasma was demonstrated by centrifugation experiments or gel filtration. Gel filtration of plasma depleted of fat by centrifugation showed the proteins only in their monomeric form. The corresponding porcine proteins displayed a binding to antibodies against the human proteins, but with a lower affinity than the homologous interactions. The binding was weak but could differentiate between the porcine proforms and activated ones, i.e., procolipase and colipase87.

Adolescent↗
PubMed1984

One-step purification of procolipase from human pancreatic juice by immobilized antibodies against human colipase86.

Purified antibodies to human colipase86 were coupled to CNBr-activated Sepharose 4B. The immunoadsorption column thus obtained was used to purify procolipase from human pancreatic juice in one step by immunoaffinity chromatography. A single form of procolipase was obtained, having similar biological properties as previously characterized procolipases from horse and pig. The sequence of the N-terminal propeptide was determined to be Ala-Pro-Gly-Pro-Arg. In bovine, equine and porcine procolipases the corresponding N-terminal sequence is Val-Pro-Asp-Pro-Arg.

Amino Acids↗
PubMed1984

The primary sequence of human pancreatic colipase.

The amino acid sequence of an activated colipase purified from human pancreas was determined. The protein consists of a single polypeptide chain of 86 amino acids (human colipase86) and has a molecular weight of 9289. The sequence was determined by automated Edman degradation of the reduced and S-carboxymethylated protein and of two CNBr peptides. Sequence determination of porcine procolipase II was also performed, which showed that in the original sequence determination apparently two residues were missed. These residues were determined to be a leucine at position 37 and a serine in position 50. For comparison with porcine and equine procolipases, the residues composing human colipase are numbered from 6 to 91. No human procolipase has been isolated so far. The colipases from man, pig, horse and chicken show a high degree of homology: human colipase differs from the other proteins by substitutions of 19 (porcine), 24 (equine A) and 21 (equine B) residues, respectively.

Amino Acid Sequence↗
PubMed1983

The complete primary structure of phospholipase A2 from human pancreas.

The complete amino acid sequence of phospholipase A2 (phosphatide 2-acylhydrolase, EC 3.1.1.4) from human pancreas was determined. The protein consists of a single polypeptide chain of 125 amino acids and has a molecular weight of 14003. The chain is cross-linked by seven disulfide bridges. The main fragmentation of the polypeptide chain was accomplished by digestion of the reduced and thialaminated derivative of the protein with clostripain, yielding three fragments. The largest fragment (residues 7-100) was further degraded both with staphylococcal proteinase and chymotrypsin. The sequence was determined by automated Edman degradation of the intact protein and of several large peptide fragments. Phospholipase A2 from human pancreas contains the same number of amino acids (125) as the enzyme from horse, while the enzymes from pig and ox contain 124 and 123 residues, respectively. The enzymes show a high degree of homology; human phospholipase differs from the other enzymes by substitutions of 26 (porcine), 28 (bovine) and 32 (equine) residues, respectively.

Amino Acid Sequence↗
PubMed1983

Evolutionary studies on pancreatic colipase.

In this evolutionary study the following criteria have been used to prove the existence of colipase: 1. It restores the activity of human and porcine pancreatic lipase inhibited by bile salt. 2. It cross-reacts with antisera to human and porcine colipases. 3. Its restoration of lipase activity, inhibited by bile salt, in the tributyrin assay system, is prevented by antiserum to colipase. 4. It is a heat-stable, low-molecular-weight protein (molecular weight about 10 000 by gel-filtration). The occurrence of colipase has been verified in the exocrine pancreatic cells from hagfish (Myxine glutinosa), ratfish (Chimaera monstrosa), rayfish (Raja radiata). Greenland shark (Somnius microcephalus) and dogfish (Squalus acanthius). No colipase activity could be found in the gastric juice of crayfish (Pacifastacus leniusculus). These results indicate that colipase envolved in the vertebrates before the organized exocrine pancreatic gland and occurred simultaneously with the bile salts/bile alcohols.

Animals↗
PubMed1982

Measurement of the binding of human colipase to human lipase and lipase substrates.

Equilibrium partition in an aqueous two-phase system was the method used for quantitative determinations of the binding between human colipase and human lipase and three triacylglycerol substrates: Intralipid tributyrin and triolein. The measurements were performed in a dextran/polyethyleneglycol system at pH 7.0 in the presence of 2 mM sodium taurodeoxycholate and 150 mM NaCL. The binding of colipase to lipase had a dissociation constant Kd = 4.8 . 10(-8) M. The dissociation constants for the binding of colipase to Intralipid, tributyrin and triolein were found to be 2.10(-7) M, 4.8 . 10(-8) M and 6.2 . 10(-8) M, respectively.

Colipases↗
PubMed1979

Purification and characterization of human pancreatic colipase.

Two colipases, named colipase I and colipase II, have been isolated from extracts of human pancreatic gland. The two proteins can be separated by ion-exchange chromatography, isoelectric focusing and slab technique gel electrophoresis. The result of this study indicates that the two colipases, both of which are glycoproteins, have identical amino acid compositions. The pI values were found to be 6.1 for colipase I and 5.8 for colipase II. The different colipases have also been found in human pancreatic juice. The N-terminal amino acid was glycine for both colipase I (gland) and colipase II (juice). Only minor differences were found between the colipases isolated from gland and juice, and colipase I from gland alone was examined in detail.

Amino Acid Sequence↗
PubMedDate not supplied

Secretin and gastric lipase secretion.

BACKGROUND: Gastric lipase secretion is stimulated by gastrin in plasma, but its regulation by secretin is unknown. METHODS: In 7 normal persons we investigated the effect of exogenous secretin on the output of gastric lipase stimulated by intravenous gastrin-17. The gastric content was measured using a nasogastric tube for aspiration. The quantitative lipase secretion was measured by an enzyme-linked immunosorbant assay (ELISA) and the lipolytic activity by a kinetic assay. Plasma concentrations of secretin and gastrin were measured by radioimmunoassay. RESULTS: Gastric lipase secretion (the quantity as well as the lipolytic activity) was significantly stimulated by gastrin. In response to secretin infusion, the lipolytic activity increased as acid secretion decreased. CONCLUSION: Secretin in postprandial concentrations does not influence the quantitative gastric lipase secretion stimulated by gastrin, but it increases lipolytic activity due to inhibition of acid secretion.

Adult↗