Laszewicz W

Serum profiles of E-selectin, interleukin-10, and interleukin-6 and oxidative stress parameters in patients with acute pancreatitis and nonpancreatic acute abdominal pain.

Introduction Excessive inflammatory response is one of the major causes of early mortality in acute pancreatitis (AP). Aim To evaluate the serum profiles of E-selectin, interleukin (IL)–6, and IL-10 along with their correlation to the markers of oxidative stress and neutrophil activation in patients with AP and patients with nonpancreatic acute abdominal pain (NPAAP). Methodology This prospective clinical study included 56 patients with AP (28 with mild AP and 28 with severe AP) as well as 15 patients with NPAAP. Results Serum concentrations of E-selectin, IL-10, and IL-6 and plasma concentrations of polymorphonuclear leukocyte elastase (determined on days 1–3, 5, and 10 after admission) were the highest in severe AP during the first 3 days and then declined. At day 10, the E-selectin level in severe AP was still higher than that in mild AP, and the IL-10 concentration increased again. There was no elevation in the E-selectin concentration in NPAAP patients, and IL-10 levels remained unchanged in mild AP. Oxidative stress, measured by serum malondialdehyde and 4-hydroxyalkenals levels, was the most pronounced in severe AP. Conclusions The serum E-selectin concentration is markedly elevated in severe AP and is less in mild AP but not in NPAAP. It may result from stimulation with different inflammatory mediators or indicate vascular endothelium injury mediated by oxidative stress, especially in the severe form of AP.

Activity of class I, II, III, and IV alcohol dehydrogenase isoenzymes in human gastric mucosa.

The gastric alcohol dehydrogenase (ADH) plays an important role in the “first pass” metabolism of ethanol. Human ADH exists in multiple forms, grouped into six classes and located in different tissues. In present study we investigated the activity of four classes (I, II, III, and IV) of alcohol dehydrogenase isoenzymes in the different parts of stomach (corpus and antrum) in patients with suspected gastric ulcer. The aim of the study was assess the particular role of different classes of ADH in the gastric dehydrogenase activity. For the measurement of the activity of class I and class II isoenzymes, we employed new fluorometric methods with specific substrates. The activity of class III alcohol dehydrogenase was measured by the photometric method with n-octanol and class IV with m-nitrobenzaldehyde as a substrate, respectively. All biopsy specimens were taken from less changed areas of the antrum and body of the stomach of 68 patients suspected of having gastric ulcer. It was found that ADH IV (gastric) activity was the highest (14.76 ± 0.68 in the corpus of the stomach in men; and 7.61 ± 0.68 in women, respectively). The activity of the ADH III isoenzyme was lower than that of ADH IV. The activities of class I and II ADH isoenzymes were barely detectable. All tested classes of ADH had higher activity in the corpus than in the antrum and in males than in females. In conclusion, the most important form of gastric ADH is isoenzyme of class IV, less important is the isoenzyme of class III. ADH classes I and II seem to have no role in the stomach.

Effect of sucralfate on the viscosity of gastric mucus and the permeability to hydrogen ion.

The effect of sucralfate on the viscosity of pig gastric mucus and on its ability to retard the diffusion of hydrogen ion was investigated. Using a cone/plate viscometer at shear rates between 1.15 and 230 s-1, it was found that preincubation of mucus with increasing concentrations of sucralfate led to a gradual enhancement of the mucus viscosity. This enhancement in viscosity was proportional to the sucralfate concentration up to 1.0 X 10(-4) M and increased about 18% for each 10-fold increment in its concentration. The permeability measurements, conducted in a specially designed two compartment chamber, revealed that addition of sucralfate to gastric mucus had a profound beneficiary effect on its ability to retard the diffusion of hydrogen ion. In the presence of 1.0 X 10(-6) M sucralfate the permeability of mucus to hydrogen ion decreased by 35%, while the 1.0 X 10(-3) M sucralfate reduced the mucus permeability by 68%. The results show that sucralfate increases the viscosity of gastric mucus and improves its ability to impede the hydrogen ion penetration.

In Vitro Inhibition of Peptic Degradation of Porcine Gastric Mucus Glycoprotein by Sucralfate

The effect of sucralfate on the proteolytic activity of pepsin towards gastric mucus glycoprotein was investigated. Mucus glycoprotein isolated from pig stomach was incubated with pepsin with and without sucralfate, and the released alpha-amino residues were quantitated. In the absence of sulcralfate the rate of proteolysis was proportional to mucus glycoprotein concentration up to 450 micrograms and remained constant with time of incubation for up to 1 h. The apparent Km value of pepsin towards mucus glycoprotein was 8.7 X 10(-7) M. Introduction of sucralfate to the reaction mixtures resulted in reduction of the rate of glycoprotein proteolysis. The rate of inhibition was proportional to the sucralfate concentration up to 1 microM and was of the competitive type, with an apparent Ki value of 2.0 X 10(-6)M. The results suggest that among the beneficial effects of sucralfate on ulcer healing, one may be attributed to its ability to interfere with peptic digestion of gastric mucus glycoprotein.

Mucolytic effects of Helicobacter pylori.

The mechanisms associated with colonization of human gastroduodenal mucosa by Helicobacter pylori remain unclear. To colonize gastric-type epithelium H. pylori must enter the gastric lumen, resist damage by all bactericidal factors operating within the acidic gastric milieu, penetrate the mucus gel despite highly viscous and hydrophobic properties of the mucus layer, and, finally, secure optimal conditions for its further multiplication. Since the H. pylori microorganism has been seen freely spread throughout the entire mucus layer thickness as well as in intimate contact with surface epithelium, the interrelationship between this spiral microorganism and the mucus seems to be of paramount importance. H. pylori has been shown to affect adversely the chemical and physical properties of the mucus layer. Therefore, the mucus layer compromised by the presence of this microorganism may become an easy target for acid and peptic damage, which ultimately leads to mucosal pathology, inflammation and/or peptic ulcer disease.

Effect of Ethanol on the Peptic Degradation of Gastric Mucus Glycoprotein

The effect of ethanol on the proteolytic activity of pepsin towards gastric mucus glycoprotein was investigated. Undegraded mucus glycoprotein isolated from pig stomach was incubated with pepsin in the presence and absence of ethanol, and the released alpha-amino residues were quantitated by the trinitrophenylation procedure. In the absence of ethanol the rate of proteolysis was proportional to mucus glycoprotein concentration up to 450 micrograms and remained constant with time of incubation for at least 30 min. The apparent Km value of pepsin for pig gastric mucus glycoprotein was 8.7 X 10(-7)M. The proteolytic activity of pepsin towards mucus glycoprotein was inhibited by ethanol. The rate of inhibition was proportional to the ethanol concentration up to 0.8 M and was of competitive type. The apparent K1 value calculated from the double-reciprocal plots for ethanol was 2.2 X 10(-6)M. The inhibitory effect of ethanol on the proteolysis of gastric mucus glycoprotein may be of physiological significance.

Effect of sucralfate on the viscosity and retardation of hydrogen ion diffusion by gastric mucus glycoprotein.

The effect of an antiulcer drug (sucralfate) on the viscosity and the ability of pig gastric mucus glycoprotein to retard the diffusion of hydrogen ions was investigated. Preincubation with sucralfate produced a marked enhancement in the glycoprotein viscosity. This enhancement was concentration-dependent and at 1.0 X 10(-3) M sucralfate a 60% increase in viscosity was attained. Permeability measurements revealed that sucralfate caused a substantial improvement in the ability of the glycoprotein to retard the diffusion of hydrogen ions. At 1.0 X 10(-3) M sucralfate, permeability decreased by 25% and a 43% reduction was obtained with 1.0 X 10(-3) M sucralfate. It is suggested that sucralfate, by increasing the viscosity of the glycoprotein and by improving its ability to retard the diffusion of hydrogen ions, strengthens the integrity of gastric mucus.

Lysolecithin Affects the Viscosity, Permeability, and Peptic Susceptibility of Gastric Mucin

The effect of lysolecithin and lecithin on gastric mucin viscosity, permeability to hydrogen ion, and degradation by pepsin was investigated. Preincubation with lysolecithin produced a marked decrease in the glycoprotein viscosity. This decrease was concentration-dependent and at 10 mM lysolecithin reached a value of 74%. A 25% increase in mucin viscosity was obtained with 10 mM lecithin. Permeability measurements showed that 10 mM lecithin increased the retardation ability of the glycoprotein to hydrogen ion by 11%, whereas a 12% decrease in the retardation capacity of the glycoprotein was obtained with 10 mM lysolecithin. The results of peptic activity assay indicated that whereas lecithin had no effect on the rate of mucin proteolysis, the lysolecithin exerted significant (75%) stimulatory effect. The results suggest that lysolecithin in the stomach weakens the integrity of the protective mucus layer by promoting peptic degradation, reducing the ability to resist acid penetration, and decreasing viscosity of its mucin component.

Lipids of developing dental plaque in caries-resistant and caries-susceptible adult people

Dental plaque maturation in both caries-resistant (CR) and caries-susceptible (CS) subjects was accompanied by a decrease in total lipid content but was more pronounced with CR subjects; their plaque after 72 h contained 44.6 per cent less lipids than that of CS. At each stage of maturation, differences were also found in the proportion of lipid classes. In 24 h-plaque, the lipids of CR-group, although containing amounts of glycolipids and phospholipids similar to those of CS, contained 1.6 times less neutral lipids. The 48 h-plaque of CS subjects showed 2.5 times more neutral lipids, 1.2 times more phospholipids and 1.4 times less glycolipids. The 72 h-CR plaque contained 1.9 times less neutral lipids, 1.6 times more glycolipids and 1.3 times more phospholipids than CS-plaque. Among the neutral lipids in both groups, the changes with maturation were associated with decrease in free fatty acids and increase in triglycerides, cholesterol and cholesteryl esters. Phospholipids of CR-plaque contained less phosphatidylcholine and more phosphatidylethanolamine than CS-plaque. With plaque maturation both groups showed decreases in the glycolipids characteristic of saliva and an increase in the content of bacterial type of glycolipids. Plaque maturation is evidently accompanied by dynamic changes in lipids reflecting a shift from salivary to bacterial contribution.

Alcohol dehydrogenase (ADH) isoenzymes and aldehyde dehydrogenase (ALDH) activity in the sera of patients with acute and chronic pancreatitis

OBJECTIVE Acute and chronic pancreatitis is a major complication of alcohol abuse. The pancreas can metabolize ethanol via oxidative pathway involving the enzymes - alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) as well as the nonoxidative pathway. Human pancreas tissue contains various ADH isoenzymes and possesses also ALDH activity. In this paper we have measured the activity of alcohol dehydrogenase isoenzymes, and aldehyde dehydrogenase in the sera of patients with acute and chronic pancreatitis. METHODS Serum samples were taken for routine biochemical investigation from 46 patients suffering from acute pancreatitis and 32 patients with chronic pancreatitis. Total ADH activity was measured by photometric method with p-nitrosodimethylaniline (NDMA) as a substrate and ALDH activity by the fluorometric method with 6-methoxy-2-naphtaldehyde as a substrate. For the measurement of the activity of class I isoenzymes we employed the fluorometric methods, with class-specific fluorogenic substrates. The activity of class III alcohol dehydrogenase was measured by the photometric method with n-octanol and class IV with m-nitrobenzaldehyde as a substrate. RESULTS A statistically significant increase of class III alcohol dehydrogenase isoenzymes was found in the sera of patients with acute and chronic pancreatitis. The median activity of this class isoenzyme in the patients group increased about 35% in the comparison to the control level. The total alcohol dehydrogenase activity was also significantly higher (23.5%) among patients with pancreatitis than healthy ones. The activities of other tested ADH isoenzymes and total ALDH were unchanged. The activity of the class I ADH isoenzyme was significantly higher in the sera of heavy drinkers with pancreatitis. CONCLUSION We can state that the increase of the activity of class III alcohol dehydrogenase isoenzyme in the sera of pancreatitis patients seems to be caused by the release of this isoenzyme from damaged pancreatic cells.