Heterogeneity of high-density lipoprotein particles and insulin output during oral glucose tolerance test in men with coronary artery disease.

We compared the high-density lipoprotein (HDL) composition and particle heterogeneity in 60 nonobese (normal body mass index, BMI) men suffering from coronary artery disease (CAD) with normolipemia and normoinsulinemia with lower and higher insulin output during the oral glucose tolerance test (silent hyperinsulinemia). The apolipoprotein apoAI, apoAII, and apoE levels were higher in the high insulin response (HI) group than in low insulin response (LI) group. The ratio of apoAI versus total protein and the ratio of apoAI versus total cholesterol were increased in HI compared with LI. The lipid components in HDL were higher in LI than in HI, while for HDL2 they were higher in HI. The fractioning of HDL by gradient gel electrophoresis revealed a different pattern of HDL particles in both groups. The larger particles, HDL2b and HDL2a (mean particle diameters 10.6 and 9.2 nm, respectively), occur more frequently in HI patients (up to 60%) than in LI patients, whereas the smaller particles, HDL3a and HDL3b (mean particle diameters 8.6 and 7.8 nm, respectively), predominate in LI patients. Our results demonstrate that even in the normoglycemic, normocholesterolemic CAD patients, a high insulin output observed during the oral glucose tolerance test may be connected with a different HDL particle pattern, which suggests changes in the reverse cholesterol transport.

Influence of SIN-1 and sodium nitroprusside (NANP) on ox-LDL metabolism in macrophages.

Effects of NO-donors (3-morpholinosydnonimine-SIN-1 and sodium nitroprusside NaNP) on the accumulation and degradation of oxidized LDL (ox-LDL) by macrophages were studied. Ox-LDL, but not native-LDL (n-LDL) suppressed the LPS-stimulated biosynthesis of NO by macrophages. SIN-1 at low concentrations < 100 microM was without any effect while SIN-1 at high concentration (300 microM) and NaNP (30-300 microM) stimulated the accumulation and degradation of ox-LDL by macrophages. The pretreatment of macrophages with NG-monomethyl-L-arginine (L-NMMA, 3 microM) for 24 hours had the same stimulatory effect. The inhibition of endogenous formation of NO, by L-NMMA profoundly changed the pattern of action of NO-donors on ox-LDL catabolism by macrophages; the stimulatory action of SIN-1 was transformed to the inhibitory action on the accumulation and degradation of ox-LDL whereas NaNP lost its stimulatory action entirely. Our interpretation of this unexpected interactions between SIN-1, NaNP and L-NMMA is as follows. Endogenous NO in macrophages inhibits the accumulation of ox-LDL and therefore, the stimulatory effect of L-NMMA has been overcome by exogenous NO from SIN-1. However, NO at high concentrations promotes lipid accumulation in macrophages and thereby, in the absence of L-NMMA, SIN-1 at high concentrations and NaNP produced a paradoxical stimulatory effect in macrophages. NaNP is not a proper NO-donor and its mode of action differed from that of SIN-1. In conclusion, NO at low physiological concentrations keeps scavenger receptors of macrophages downregulated and hence endogenous NO may show anti-atherogenic properties.

Trypsinogen expression by two human pancreatic cell lines CFPAC-1 and CAPAN-1. Modulation during spontaneous and induced cell growth.

We previously demonstrated that two human pancreatic adenocarcinoma cell lines, CFPAC-1 (established from a patient with cystic fibrosis) and CAPAN-1, were able to secrete trypsinogens 1 and 2 specifically. In order to analyze the relation of trypsin secretion to differentiation and cell growth, we undertook a comparative study of immunoreactive trypsin 1 (IRT) secretion by the two cell lines during cell growth in the presence and in the absence of various differentiating agents: sodium butyrate (NaBut), dimethylsulfoxide (DMSO), and dexamethasone (DX). In the presence of NaBut, IRT levels in the supernatants of both cell lines were slightly increased, whereas the cellular growth of both cell lines decreased significantly. In the presence of DX, IRT levels in cell culture conditioned media immediately and dramatically decreased, but the cell growth of neither cell line was affected by DX. An important increase in IRT levels was observed when CFPAC-1 cells and CAPAN-1 cells were grown in the presence of DMSO, but for both cell lines the cellular growth decreased in the presence of DMSO. Our data show that neither the IRT secretion level nor the differentiation state of these cell lines correlates with cellular growth, and suggests that the expression of pancreatic proteases by these two tumor cell lines could be either related to a common stem cell with this potential or to a possible acinar origin of pancreatic cancer, as recently proposed by others.

Modulation of LDL catabolism by sodium nitroprusside and PGE2 in human peripheral blood lymphocytes.

The effect of nitric oxide donor--sodium nitroprusside (NaNP) and PGE2 on the LDL-receptor activity and LDL cellular accumulation by isolated human blood lymphocytes was investigated. Preincubation of lymphocytes with lipoprotein deficient medium (LPDS) resulted in the increase of the LDL-receptor activity and the LDL-cellular accumulation. NaNP (30-300 microM) dose-dependently prevented the increase of the LDL-receptor activity as well as the accumulation of LDL by lymphocytes. However, in "starwing" cells (cells with high LDL-receptor activity) the effect of NaNP on the receptor activity was biphasic. At concentration up to 100 microM NaNP inhibited, while at a concentration of 300 microM, it activated the LDL-receptor activity. PGE2 (3-30 microM) inhibited LDL catabolism, however, this effect was hardly concentration-dependent.

Acid and neutral lipase activity in lymphocytes of patients with increased serum cholesterol and triglyceride level.

Acid lipase activity (ALA) and neutral lipase activity (NLA) in lymphocytes of patients with primary hyperlipidemia (hypercholesterolemia or/and hypertriglyceridemia) were compared with that of an age-matched control group (blood donors). The specificity of lipase was confirmed by the use of cardiolipin the well known activator of acidic lipase. beta-D-glucuronidase activity was used as a marker of the lysosomal release reaction. ALA (by 33%) and beta-D-glucuronidase (by 55%) activity, but not NLA in lymphocytes of the group of hyperlipidemic patients, was significantly lower when compared to the control group. A negative correlation between the serum cholesterol level and ALA, NLA and beta-D-glucuronidase release from lymphocytes of hyperlipidemic subjects was observed. The serum HDL cholesterol level was positively correlated with ALA within this group. These results suggest that the high cholesterol level in serum can unspecifically supress ALA and (to the smaller degree) NLA activity in lymphocytes of hyperlipidemic subjects. The decrease of lipase activity may promote deposition of lipids in cells and the development of atherosclerosis. The parallel decrease of beta-D-glucuronidase activity in lymphocytes of hypercholesterolemic patients suggests the impairment of immune system in hypercholesterolemia.

Monoclonal antibodies to human pancreatic trypsin 1 inhibit the activation of human trypsinogens 1 and 2.

Two monoclonal antibodies (Mab) raised against human pancreatic trypsin 1, Mab G6 and A8, were previously isolated and characterized. The two Mab which recognize trypsinogen 1 are found to inhibit the activation of trypsinogen 1 by enterokinase. The inhibition of activation by the two Mab is concentration-dependent, rapid and virtually complete with Mab G6. Activation of trypsinogen 2 is totally inhibited by Mab G6, while Mab A8 has no effect on the activation of trypsinogen 2. The two monoclonal antibodies have opposite effects on the proteolytic activity of trypsin 1; Mab G6 increases proteolytic activity while Mab A8 inhibits trypsin activity by as much as 40%. This inhibition is concentration dependent but cannot account for the complete inhibition of activation of trypsinogen 1. Neither monoclonal antibody significantly inhibits the esterolytic activity of either form of human trypsin. Western-blot analysis of the reactivity of the two monoclonal antibodies with trypsinogens of various species shows that only Mab G6 cross-reacts with dog trypsinogen.

Characterization of trypsinogens 1 and 2 in two human pancreatic adenocarcinoma cell lines; CFPAC-1 and CAPAN-1.

Proteins with trypsin-like immunoreactivity (first detected by a specific immunoenzymatic assay) were isolated from CAPAN-1 and CFPAC-1 cell culture-conditioned media by chromatography on an immunoadsorbent prepared with a polyclonal antibody directed against trypsin 1. The adsorbed proteins were devoid of free trypsin activity but trypsin activity was present after enterokinase activation demonstrating that the immunoreactive trypsin present in cell supernatants corresponds to trypsinogens. When characterised by Western blotting using a monoclonal antibody directed against human trypsin 1 two protein bands corresponding to trypsinogen 1 (23 kDa) and trypsinogen 2 (25 kDa) gave a positive reaction. These results demonstrate the presence of trypsinogens 1 and 2 in CAPAN-1 and CFPAC-1 cells and in their culture-conditioned media.

A case of abetalipoproteinaemia in a Polish family.

Abetalipoproteinaemia (ABLP) was diagnosed in a brother and sister, 9 and 13 years old, presenting with symptoms of malabsorption during the neonatal period. Both children showed most of the main clinical features of ABLP, including neurological, and ophthalmic symptoms, and mental retardation. Acanthocytosis of erythrocytes was almost complete in the affected children, while in most of the remaining 11 members of their three-generation family, it was found in less than 50% of red blood cells. Absence of apoprotein B and low concentrations of apo A-I and lipids were found only in ABLP-affected children. Among five siblings only the two affected children had ABLP-characteristic lipid storage in enterocytes. The latter features correlated better with clinical symptoms than did the acanthocytosis of erythrocytes.

[Plasma lipid and lipoprotein levels among rural and urban populations in Poland in relation to risk factors of coronary disease]. / Stezenie lipidów i lipoprotein osocza w populacji rolniczej i przemyslowej Polski zaleznie od czynników ryzyka choroby niedokrwiennej serca.

There are significant differences in plasma total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides and blood pressure, prevalence of cigarette smoking, obesity, education level and alcohol consumption found between the rural and industrial populations in Poland. It was found that the differences in plasma lipids and lipoproteins concentration are related to the differences in age, sex, education level, alcohol consumption, obesity, cigarette smoking and blood pressure. Increase of education level was related to increase in plasma concentration of total cholesterol. LDL-cholesterol and triglycerides but it was related to decrease of HDL-cholesterol. After the adjustment to all above factors the differences in total cholesterol and LDL-cholesterol between the studied populations appeared insignificant. The differences in HDL-cholesterol and triglycerides remained significant.

Possible lysosomal activation of pancreatic zymogens. Activation of both human trypsinogens by cathepsin B and spontaneous acid. Activation of human trypsinogen 1.

Human trypsinogens 1 and 2 were activated at the same rate by pure human cathepsin B at pH 3.8. Human trypsinogen 1 was also spontaneously activated during incubation at acidic pH, activation being most rapid at pH 5.0. In contrast, trypsinogen 2 showed little or no activation under these conditions. The presence of calcium salts (20mM) delayed the onset of activation under all conditions tested. These findings support the proposal that premature activation of the pancreatic zymogens may result from their entry into the lysosomal system in pancreatitis.

Serum trypsin inhibitory activity and alpha-1-antitrypsin level in liver diseases.

Alpha-1-antitrypsin level and serum trypsin inhibitory activity were measured in patients with viral hepatitis, chronic hepatitis and liver cirrhosis. The most pronounced discrepancy between these two parameters were observed in patients with liver cirrhosis: the increase of alpha-1-At level was not accompanied by adequate increase of trypsin inhibitory activity. Some mechanisms potentially responsible for this discrepancy are discussed.

Alpha 1-proteinase inhibitor in pure human pancreatic juice. Characterization of a complexed form in patients with chronic calcifying pancreatitis and its significance.

Two forms of alpha 1-proteinase inhibitor (alpha 1-PI) were characterized in the pancreatic juice of patients with chronic pancreatitis, one free form and one form complexed with a proteinase. This complex is probably present in minute amounts in normal pancreatic juice which contains mainly free alpha 1-PI. The proteinase bound to alpha 1-PI has been identified as chymotrypsin A and the inhibitory activity of the free form of alpha 1-PI has been demonstrated. These data underline the rapid conversion of human proteolytic zymogens into active enzymes and demonstrate the increase of this activation phenomenon in the juice of patients with chronic pancreatitis.

Alpha 1-proteinase inhibitor in pure human pancreatic juice.

The presence of alpha 1-proteinase inhibitor (alpha 1-PI) in pure human pancreatic juice was demonstrated. Its concentration was measured using the radial immunodiffusion technique and compared to transferrin and albumin concentrations. In normal pancreatic juice the mean alpha 1-PI level (expressed in percent of total protein) was 0.21 +/- 0.02, whereas the mean levels of the two other serum proteins were 0.14 +/- 0.01 for transferrin and 0.90 +/- 0.07 for albumin. These levels increased significantly in the juice of patients with chronic calcifying pancreatitis. The serum origin of alpha 1-PI present in pancreatic juice was demonstrated by the good correlation existing between alpha 1-PI and albumin as well as between transferrin and albumin. In addition, in each case the alpha 1-PI level was found to be higher in secretin-stimulated juice than in cholecystokinin-stimulated juice. A similar pattern was also found for albumin.

Effect of ranitidine, a new H2-antagonist, on gastric and pancreatic secretion in duodenal ulcer patients.

The effects of a new H2-receptor blocker, ranitidine, given intravenously (for comparison with cimetidine) or orally an gastric and pancreatic secretion have been studied in duodenal ulcer patients. Ranitidine appears to be several times more potent and a longer-acting inhibitor of gastric secretion than cimetidine. This H2 blocker does not affect pancreatic bicarbonate and enzyme secretion.