Lipid catabolism of cultivated treponemes

Treponema require long-chain fatty acids for growth in vitro. Serum, added to culture media, provides a source of long-chain fatty acids. These fatty acids, however, are esterified to triglycerides, phospholipids, and cholesterol. In this study, the major pathways of complex lipid catabolism in T. phagedenis, T. denticola, T. refringens, T. minutum, and T. vincentii were investigated. Lipase activity was demonstrated in five Treponema species using four lipid substrates. Chromatographic data demonstrated that, during growth, treponemes completely utilized lysophosphatidylcholine, present in serum-supplemented culture media, while phosphatidylcholine and phosphatidylinositol were not utilized. Phospholipase B and glycerophosphorylcholine diesterase activities were demonstrated in the five species of Treponema studied. Treponema phagedenis and T. denticola had phosphatase activity, while T. refringens, T. minutum, and T. vincentii did not have an acid phosphatase activity. Phospholipase A, C, and D and alkaline phosphatase activities were not found in five species of Treponema. Based on the enzymes demonstrated in this study, two pathways of phospholipid catabolism are proposed.

Pancreatic enzyme replacement: the effect of antacids or cimetidine

The effect of the addition of sodium bicarbonate, aluminum hydroxide, magnesium hydroxide, calcium carbonate, or cimetidine to supplemental pancreatic enzyme therapy was investigated in patients with severe exocrine pancreatic insufficiency. Steatorrhea was reduced with the administration of three enzyme tablets with meals (73 vs 29 g/24 hr). The coadministration of enzyme tablets with either sodium bicarbonate (16.6 g/24 hr, P = 0.08), or aluminum hydroxide (18.4 g/24 hr, P = 0.029) yielded a greater reduction in steatorrhea than enzymes alone (29 g/24 hr). Neither magnesium-aluminum hydroxide (36.3 g/24 hr, P = 0.22), nor calcium carbonate (39.0 g/24 hr, P = 0.029), improved efficacy of enzyme therapy and, in fact, tended to enhance steatorrhea. With the administration of cimetidine there was no significant effect on steatorrhea compared to enzymes alone (32.1 vs 29 g/24 hr, P greater than 0.3). Intraduodenal lipase activity following test meals was found to be a poor predictor of the effectiveness of antacid therapy in improving the efficacy of supplemental enzymes.

Effect of dietary fiber on pancreatic enzyme activity in vitro

The importance of various factors for dietary fiber effects on pancreatic enzyme activities was studied in vitro. Pectin of high methylic esterification and guar gum, which reduced enzyme activities, particularly lipase activity, increased the viscosity of duodenal juice. Increasing duodenal juice viscosity by polyethlene glycol also caused a reduction particularly of lipase activity. Pectin of low methylic esterification, which reduced especially amylase and lipase activities, significantly lowered duodenal juice pH. Lowering duodenal juice pH by hydrochloric acid caused a reduction especially of amylase and lipase activities. Pretreating fiber at acid pH tended to increase its enzyme-inhibiting properties. Trypsin adsorption to wheat bran was partly reversible by buffer washings. Changing ionic strength and incubation time appeared relatively unimportant for the effects of the fiber on enzymes. It is assumed that the inhibitory effects of the fiber on enzymes are attributed inter alia to effects on viscosity, pH, and adsorption, and further that gastric acidification of fiber and conditions lowering intestinal pH may enhance these effects.

Does mixing pancreatic enzyme microspheres (Pancrease) with food damage the enteric coating?

Supplemental pancreatic enzymes are required for the treatment of malabsorption associated with cystic fibrosis. It is a general practice for enzymes to be sprinkled on, or administered in, food given to infants or children who require pancreatic enzyme replacement. We tested the effect of in vitro incubation of enteric-coated pancreatic enzyme microspheres with infant foods on total recoverable enzyme activity and on the enteric coating. Incubation of enzyme beads with foods with pH greater than 5 (i.e., chicken pH 6.5, veal pH 6.3, and green beans pH 5.6) was without significant effect on either parameter. There was a statistically significant, albeit minor, reduction in maximum enzyme activity recovered following incubation with applesauce (pH 3.5). In addition, the thickness of the enteric coating was significantly reduced. Whether changes in the enzyme beads results in improved or diminished efficiency of therapy remains to be determined. Lipase, unprotected by enteric coating, was rapidly inactivated in applesauce, emphasizing the need to instruct parents about which foods to avoid when administering pancreatic enzymes without enteric coating.

Gastric lipase in the newborn rat

A substantial portion of rat milk triglycerides was hydrolyzed in the ligated stomach of suckling rats with excised lingual gland and pancreas, due to the action of gastric lipase. Free fatty acids were the main lipolytic products. There were some diglycerides and traces of monoglycerides. Medium chain length (C8-C12) fatty acids were predominantly recovered in the free fatty acid fraction, whereas the remaining tri- and diglycerides became richer in long chain (greater than or equal to C14) fatty acids suggesting a preferential lipolysis of medium chain fatty acid ester bonds. The lipase activity in extracts of stomach wall and sublingual gland tissue was more stable at acid pH and more resistant to the action of pepsin than the activity of pancreatic lipase. Trypsin strongly affected lingual lipase activity but only moderately reduced gastric and pancreatic lipase activity. Presence of sodium taurocholate made the lingual and gastric lipases less sensitive to proteolytic attack. It was also found that the activity of gastric lipase, related to the tissue protein content, decreased with the age of rats, whereas that of lingual lipase increased. The joint capacity of the stomach and lingual gland lipases amounted to about 50% of the total digestive lipolytic capacity 6 days after rat birth but decreased to about 20% at 60 days of life. This was due mainly to the considerable increase in the pancreatic gland size.

Porcine pancreatic lipase. Completion of the primary structure

The complete primary structure of a lipase (triacylglycerol hydrolase; EC 3.1.1.3) is presented for the first time. The porcine pancreatic enzyme which was investigated is composed of a single chain of 449 amino acids. Upon fragmentation by CNBr, five peptides were obtained. The sequence of four of them (CN I-CN IV) has already been published. The present report deals with the arrangement of the 142 amino acids of the C-terminal peptide CN V, thus completing the analysis of the whole molecule. Special problems resulting from incomplete cleavage of some peptide bonds in CN V and aggregation of large peptides were overcome using Sephadex filtration of succinylated derivatives in 50% acetic acid, automated sequence analysis of peptide mixtures and subdigestion of material which could not be directly resolved. No obvious homology was found when the sequence of porcine lipase was compared with other protein, including pancreatic phospholipase A2 and colipase from the same species. However, a few similarities which might be significant were detected between the environment and relative position of certain half cystines in lipase and colipase, as well as between two tyrosine-rich regions existing in both proteins.

Comparative studies on viscosity and concentration of protein and hexosamine in pure pancreatic juice

In order to investigate the cause of an increase in viscosity of pancreatic juice in patients with chronic pancreatitis, we performed comparative studies on voscosity and concentration of protein, hexosamine, three hydrolytic enzymes (amylase, chymotrypsinogen and lipase), calcium and gamma-Glutamyltranspeptidase in pure pancreatic juice. Pure pancreatic juice (PPJ) was obtained from seven control subjects, 10 patients with probable chronic pancreatitis and six patients with definite chronic pancreatitis by means of endoscopic retrograde catheterization of the papilla. Specimens were collected in ice-cooled tubes during the initial four-minute period and thereafter at two-minute intervals for 20 minutes after a rapid intravenous injection of secretin (Eisai Secrepan, 1 U/kg of body weight) and then at one-minute intervals for 10 minutes after a rapid intravenous injection of pancreozymin (Boots, 1 U/kg of body weight). It was demonstrated that the viscosity of PPJ was closely related to the concentration of hydrolytic enzyme protein, hexosamine and the presence of mucous substance and protein plugs.

The action of synthetic secretin, cholecystokinin-octapeptide and combinations of these hormones on the secretion of the isolated perfused rat pancreas

Determinations of dose-response curves for synthetic secretin and for the octapeptide of cholecystokinin (CCK-8) in the isolated perfused rat pancreas reveal that both secretin and CCK stimulate the pancreatic secretory flow and enzyme secretion. The maximal secretory flow evoked by CCK-8 (1.75 +/- 0.24 microliter/min) equals that evoked by secretin, while the protein output (57.1 +/- 6.3 microgram/min) is approximately twice as high. Stimulation by secretin combined with CCK-8 results in summation of the hydrokinetic action and potentiation of the ecbolic action of these hormones. Since the secretory parameters decrease by supramaximal stimulation, the dose-response curves are biphasic. The secretion of pancreatic enzymes correlates significantly (p less than 0.0005) with the protein output. However, the ratio of amylase, lipase and chymotrypsinogen to protein depends on the degree of pancreatic stimulation in so far as amylase secretion increases significantly (p less than 0.01) more markedly than that of both other enzymes.

Histochemical studies on protein plugs obtained by endoscopic retrograde catheterization of the papilla

In order to elucidate mechanisms of protein plug formation, histochemical studies were performed on aggregates and protein plugs present in pancreatic juice. Pancreatic juice was obtained from three control subjects and five patients with chronic pancreatitis through endoscopic retrograde catheterization of the papilla. Specimens for staining were prepared in two ways: (1) fixed with 10 per cent formaldehyde, embedded in paraffin and sectioned, and (2) placed on slide glass and fixed with isopropylalcohol. Staining included hematoxylin-eosin, periodic-acid Schiff, von Kossa, alcian blue, toluidine blue and double staining with PAS and AB. The process of protein plug formation can be as follows: (1) a prerequisite for aggregate formation, consisting of clusters of desquamated epithelial cells, highly concentrated sulfated acidic mucopolysaccharide and neutral mucopolysaccharide, (2) formation of aggregates in which epithelial cells and amorphous substance are interlaced with developing fine reticular substance, (3) enlargement of aggregates by fusion with adjacent aggregates through bridging action of the reticular substance sprouting, like prickles, from their surface, and (4) "maturity" of aggregates, taking a three-dimensional form which result in a spherical, spheroidal or cylindrical protein plug.

Regional effects of sulfur dioxide exposure on the guinea pig brain lipids, lipid peroxidation and lipase activity

Experiments to evaluate the neurochemical action of gaseous pollutants were performed in a specifically designed inhalation chamber. Exposure of guinea pigs to 10 ppm of SO2 for one hour daily for 21 days produced a significant depletion of total lipids and free fatty acids in all brain regions. Phospholipid and cholesterol content of the cerebellum and brain stem were also decreased, but were increased in cerebral hemisphere. Esterified fatty acids were depleted in the cerebral hemisphere and brain stem, but exhibited increment in the cerebellum. The rate of lipid peroxidation and the activity of lipase were increased significantly in all the regions of the brain. The results clearly indicate that SO2-exposure induces degradation of brain lipids. Interestingly, the lipid contents are affected differentially in the various parts of the brain.

[Lipolytic complex of Penicillium sp]

By gel filtration on Sephadex G-75 it has been demonstrated that the lipolytic complex of Penicillium sp. contains two active components--a high molecular weight (lipase-1) and low molecular weight component (lipase-2). Both components have been isolated by Sephadex gel-filtration and DEAE-cellulose chromatography. It has been shown by discelectrophoresis and isoelectric focusing that lipase-2 is a highly purified protein with the molecular weight of 30,000 (gel-filtration) or 29,000 (electrophoresis) and isoelectric point at pH 4.8 Lipase-1 has been found to contain large quantities of lipids. The conditions of deaggregation of a high molecular weight component have been identified to yield a new active component corresponding to lipase-2 in its gel-filtration and disc-electrophoresis properties. It has been shown that pH 7.5-8.0 and temperature 37-40 degrees are optimal for both lipase-1 and lipase-2. Activities of the two components are inhibited by Na deoxycholate and remain unchanged in the presence of Na cholate and dehydrocholate. On the basis of these findings it is concluded that lipase-1 and lipase-2 are two forms of the same enzyme.

Effect of probucol on cholesterol synthesis, plasma lipoproteins and the activities of lipoprotein and hepatic lipase in the rat

The postheparin plasma lipoprotein lipase (LPL) activity and plasma HDL and LDL cholesterol concentrations, decreases significantly during probucol treatment of the rat. The reduction of the LPL activity obviously took place in adipose tissue. The activity of hepatic lipase and the in vitro synthesis of cholesterol in the liver or isolated jejunal villous cells were unaffected by the probucol treatment. Plasma triglyceride and VLDL cholesterol concentrations remained similar in the control and probucol groups despite the difference in the LPL activity, whereas the esterified VLDL cholesterol level was significantly reduced in the probucol group. The results suggest that the HDL lowering action of probucol is contributed by the reduced LPL activity probably via impaired VLDL metabolism.

[Digestion of fat and protein and its relation to the activity of faecal enzymes in mucoviscidosis infants under substitution therapy with pancreatic enzymes (author's transl)]

The article reports on a study to determine the influence of different dosage schedules of a pancreas enzyme preparation on the digestion of fat and protein and on the lipolytic, tryptic and chymotryptic activity of the faeces in children suffering from mucoviscidose. After administration of the pancreatin preparation at the low dose level, the quantity of faeces, the excretion of fatty acids and of nitrogen are reduced and the absorption coefficient is improved. The faecal tryptic and chymotryptic activity increases, whereas the lipase activity in the faeces merely shows a tendency to rise. Increasing the pancreatin dose up to a still tolerable value by doubling the dosage does not result in further reduction of the excretion of fat and nitrogen although it enhances the proteolytic activity of the faeces while the lipase activity remains unaffected. Determination of the lipolytic, tryptic or chymotryptic activity is, therefore, unsuitable for assessing the fat and protein digestion and for estimating the required dose of pancreatic enzyme. No increase in uric acid excretion was seen in the urine collected for 24 hours after administration of both enzyme doses.

[Determination of amylase and lipase in peritoneal fluid: diagnostic value in ovarian cysts (author's transl)]

Two female patients aged 18 and 25 were admitted because of progressive abdominal distention, both had vague digestive complaints of several months onset, which was interpreted as ascitis. Needle aspiration yielded a clear fluid with an elevated amylase content. Lipase was within normal limits which suggested an extra-pancreatic process as the cause of amylase elevation. The sex of the patients, the non-progression of symptomatology together with good tolerance suggested the possibility of a giant ovarian cyst, which was confirmed by laparotomy. The value of lipase determination in fluid obtained by needle aspiration and high in amylase content, in ruling out pancreatic processes is discussed.

Physiological studies of exocrine pancreatic secretion in conscious rats. 3. Communication. Separation and determination of enzymes by gel-electrophoresis

1. A method is described for the electrophoretic separation and following quantitative determination of the different protein fractions of pancreatic juice. 2. A polyacrylamide (PAA) gel-electrophoresis is performed in two systems: one anionic at pH = 9.0 with 7.5% PAA and a cationic one at pH = 5.0 with 10% PAA. 3. After about two hours of separation using a current of 3 and 4 mA respectively, the gels are stained with Amido-black 10B after fixation of the proteins with acetic acid. 4. The colour in excess is removed with acetic acid. 5. The coloured bands are isolated by cutting. 6. Evaluation of the colour by NaOH and determination of the colour intensity by photometry. 7. Evaluation of the colour extinction as relative percentages of the different protein and enzyme fractions. (Extinction of total dye = 100%) 8. There are at least 13 bands in the cationic system and about 7 additional ones in the anionic system distinctly separated, 12 of them could be identified using enzymatic methods. 9. Evidence is given that the colour intensity has a linear relationship to enzyme activity. 10. The validity of the presented method is discussed and compared with other electrophoretic methods.