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C Tagesson

Publications and source records attributed to C Tagesson.

At least 145 records · Page 8Linked to original sources
PubMed1980

Purification of an enzyme with lysophospholipase activity from rat intestinal mucosa by hydrophobic chromatography.

A method based on hydrophobic chromatography is described for the purification of a lysophospholipase from the mucosa of rat small intestine. Under the conditions used, one single chromatographic run on phenyl-Sepharose CL-4B yielded a 582-fold purification with a 79% overall recovery of enzyme activity. A subsodium dodecyl sulphate gel electrophoresis; its isoelectric point is 5.6.

Animals↗
PubMed1980

Passage of molecules through the wall of the gastrointestinal tract. II. Application of low-molecular weight polyethyleneglycol and a deterministic mathematical model for determining intestinal permeability in man.

The intestinal permeability to low molecular weight polyethyleneglycol (PEG) has been evaluated by means of a simple mathematical model and computer-aided curve-fitting procedures. Macrogolum 400, a mixture of 11 PEGs with molecular weights ranging from 194 to 634 daltons, was taken together with a liquid meal and a six-hour portion of urine collected. The different PEGs were then extracted from the urine, separated from each other by gas-liquid chromatography, and the relative peak area of each individual PEG determined. The distribution of different PEGs in the urine was then compared with the original PEG-distribution in three different ways: (1) by comparing the median values of the molecular weights, (2) by comparing the mean and standard deviation after curve fitting to the normal distribution, and (3) by curve fitting to mathematical filter functions demonstrating molecular exclusion due to size. It thus appeared that molecules were excluded both in the high and in the low molecular weight range, possibly by a combined effect of the intestinal permeability barrier and an escape to other compartments than the urine. However, relatively more of the larger PEGs passed from the intestine to the urine in a patient with Crohn's disease than in an apparently healthy individual.

Adult↗
PubMed1980

Subcellular fractionation of human intestinal mucosa by large-scale zonal centrifugation. I. Characterization of subcellular organelles in the distal part of the ileum.

The subcellular organelles in human ileal mucosa have been characterized by large-scale rate zonal and isopycnic density-gradient centrifugation. Mucosal scrapings were obtained from surgical specimens and the cells disrupted by extrusion under controlled pressure. The homogenized cells were then centrifuged to prepare a cell extract and the extract fractionated in a single-step procedure by zonal centrifugation on a continuous sucrose gradient. The subcellular organelles (brush borders, basal-lateral membranes, lysosomes, mitochondria, and endoplasmic reticulum) were located in the density gradient by assay of marker enzymes. Since a large number of analyses can be done on each fraction of interest, this fractionation technique may be used to study a variety of compounds and concepts involved in the subcellular physiology and pathology of human ileal mucosa.

Adult↗
PubMed1980

Altered gallbladder bile composition in gallstone disease. Relation to gallbladder wall permeability.

The possible role of conjugated bile salts in the induction and mediation of acute aseptic cholecystitis has been assessed. Using an experimental model, we determined the passive permeability to fluorescently labelled dextran in the gallbladder wall when exposed to different bile salts, alone or together with lecithin. Both taurocholate (20 mM) and, in particular, taurodeoxycholate (20 mM) markedly increased the transmural passage of dextran, but this effect was inhibited by lecithin (50 mM). Bile from patients with cholesterol gallstones contained relatively more deoxycholates (19.4% +/- 8.6%) and less lecithin (35 +/- 20 mmol/l) than did bile from patients with uncomplicated gastric disease (14.1 +/- 6.0% deoxycholates and 53 +/- 26 mmol lecithin/l). Since deoxycholates are more inflammation-promoting than cholates in several systems, and lecithin is considered necessary for protection against the devastating effects of bile salts, these findings should not be overlooked in current hypotheses on the pathogenesis of acute calculous cholecystitis.

Adult↗
PubMed1980

Subcellular fractionation of human intestinal mucosa by large-scale zonal centrifugation. Characteristics of lysosomes and brush border membranes in the distal ileum of a patient with Crohn's disease.

Lysosomes and brush border membranes from diseased ileal mucosa of a patient with Crohn's disease were separated by rate zonal density gradient centrifugation. The organelles were located and characterized in the density gradient of assay of marker enzymes, and their enzyme content compared to that of similar organelles from normal tissue. The activity and latency of lysosomal enzymes (N-acetyl-beta-glucosaminidase and acid phosphatase) was significantly increased, whereas the activity of brush border alkaline phosphatase was rather decreased. The possible relevance of these findings to the pathophysiology of Crohn's disease is discussed.

Acetylglucosaminidase↗
PubMed1980

Subcellular fractionation of human intestinal mucosa by large-scale zonal centrifugation. Separation of the organelles in diseased ileum of a patient with Crohn's disease.

The subcellular organelles in diseased ileal mucosa of a patient with Crohn's disease have been separated by rate zonal density gradient centrifugation. Mucosal scrapings were obtained from a surgical specimen of diseased intestine and the cells disrupted by extrusion under controlled pressure. The homogenized cells were then centrifuged to prepare a cell extract and the extract fractionated in a single-step procedure by zonal centrifugation on a continuous sucrose gradient. The subcellular organelles (brush borders, basal-lateral membranes, lysosomes, mitochondria and endoplasmic reticulum) were located in the density gradient by assay of marker enzymes and their overall distribution compared with the distribution of organelles from a normal tissue. The centrifugal properties of individual organelles in the diseased tissue were largely unaffected but the lysosomes were more fragile than in the normal tissue. Since the fractionation technique used is on a large scale, each fraction of interest can be further analyzed for a variety of compounds. Therefore, the subcellular pathology and pathophysiology in this and other cases of Crohn's disease may eventually be studied and discussed in other than morphological and descriptive terms.

Aged↗
PubMed1979

The prerequisites for local lysolecithin formation in the human gallbladder. III. Demonstration of two different phospholipase A activities.

The positional specificity of the phospholipase A (EC 3.1.1.4) in human gallbladder epithelium has been studied using 14C-phosphatidylethanolamine radiolabeled either in the 1-acyl or in the 2-acyl position. After heating of homogenized epithelial cells at 70 degrees C for 2 min, their lysophospholipase activity was lost. In contrast, the ability to hydrolyze 14C-phosphatidylethanolamine in biosynthetically radiolabeled Escherichia coli was largely retained. The amounts of radioactivity found in the products of hydrolysis under different conditions suggest that there are two different phospholipase A activities in the gallbladder epithelium: one, with optimal activity at pH 7, that requires Ca2+ and is specific for the 2-acyl position, and another, with optimal activity at pH 4, that does not require Ca2+ and that, apart from the 2-acyl position, attacks the 1-acyl position as well. It is possible, therefore, that a complete deacylation of diacylphosphoglycerides in the gallbladder wall is brought about in two different ways: at neutral pH through a combined action of phospholipase A2 and lysophospholipase, the latter being able to hydrolyze the 1-acyl-lysophosphoglyceride, and, at acid pH, through the action of phospholipase A1 and A2 activity, presuming 1-acyl- and 2-acyl-lysophosphoglycerides are also attacked. Both these processes have to be considered in order to explain a turnover of diacylphosphoglycerides that physiologically would prevent the accumulation of lytic lysophosphoglycerides. The possible relevance of these findings to the pathogenesis of aseptic cholecystitis is inferred.

Calcium↗
PubMed1978

The biochemical prerequisites for preventing pathogenic lysolecithin activity in the human gallbladder. II. Studies on the subcellular localization of lysophospholipase.

The subcellular localization of lysophospholipase activity in the human gallbladder epithelium was studied by differential and density gradient centrifugation. The highest relative specific activity was found in the microsomal fraction, although the enzyme appeared in mitochondria and lysosomes as well. The cytosol did not contain any significant lysophospholipase activity, but large amounts of enzyme were solubilized during centrifugation in sucrose gradients. These findings are discussed in relation to the distribution and properties of lysophospholipase in other cells and tissues and with regard to physiological implications. The possible relevance to the pathogenesis of aseptic cholecystitis is inferred.

Centrifugation, Density Gradient↗
PubMed1978

Passage of molecules through the wall of the gastrointestinal tract. I. A simple experimental model.

We describe here a simple experimental model for studying how the structural integrity of the intestinal wall is related to the transmural passage of molecules into the circulation. The model is based on the deposition of fluorescently labeled dextran in the intestine and its eventual recovery in the portal blood and mesenteric lymph. The fluorescent compound can be determined with sensitivity and ease by using fluorescence spectrometry. As judged from chromatography on Sephadex G-100, the compound was not degraded or otherwise chemically altered on its route of passage. The rate of passage was inversely proportional to the molecular size. The model may prove useful for studying factors that influence the transmission of macromolecules across the intestinal wall. Such a transmission probably underlies the pathogenesis of a variety of diseases.

Animals↗
PubMed1978

The prerequisites for local lysolecithin formation in the human gallbladder. II. Studies on the positional specificity of the phospholipase A activity.

The positional specificity of the phospholipase A in human gallbladder epithelium was studied by using biosynthetically radioabeled diacylphosphoglycerides as substrates. Diacylphosphoglyceride in 14C-palmitic acid-labeled, autoclaved E.coli was hydrolyzed under the formation of monoacylphosphoglyceride and fatty acid that were both radiolabled. In contrast, diacylphosphoglyceride in 14C-oleate-labeled bacteria was hydrolyzed so as to give radiolabel in the fatty acid only. Since 14C-palmitate occupies predominantly the 1-acyl position and 14C oleate the 2-acyl position of the major E. coli diacylphosphoglycerides, these findings suggest that: 1) the phospholipase attacks and 2-position of diacylphosphoglycerides, and 2) a complete deacylation of diacylphosphoglycerides in the gallbladder wall is brought about by the combined action of phospholipase A2 and lysophospholipase, the latter being able to hydrolyze the 1-acyllysophosphoglyceride. It appears, therefore, that the biochemical preequisites for a local formation and degreadation of lysolecithin in the gallbladder itself are met by the positional specificity of theenzymes present. This finding further substantiates the hypothesis that lysolecithin is an adjustable mediator of aseptic cholecystitis.

Cholecystitis↗
PubMed1977

The tendency of smooth and rough Salmonella typhimurium bacteria and lipopolysaccharide to hydrophobic and ionic interaction, as studied in aqueous polymer two-phase systems.

In aqueous two-phase system, the partition of bacteria and lipopolysaccharide from a rough (R) strain (Rd-mutant) of Salmonella typhimurium is influenced by polymers with covalently linked hydrophobic groups indicating hydrophobic structures accessible at the cell surface. Furthermore, the partition of the R bacteria is influenced by a number of inorganic positive and negative ions, presumably as a consequence of interaction with negatively charged surface structures. In contrast, smooth (S) bacteria and lipopolysaccharide from the parent strain do not seem to participate in either hydrophobic or charge interaction indicating extensive hydrophilicity without charge. Thus, the S-specific polysaccharide side chain of S. typhimurium might serve the purpose of blindfolding aspecific host defence mechanisms dependent on hydrophobicity and charge. On the contrary, the R bacteria and R lipopolysaccharide have physico-chemical properties which predispose to interaction with several types of cells, organelles and molecules.

Dextrans↗