Different anticancer effects of fluvastatin on primary hepatocellular tumors and metastases in rats

Rats (FLF1) were pretreated with 2 and 20 mg/kg/day fluvastatin (Flu), and after 6 weeks, hepatocellular tumor cells were inoculated under the left renal capsule. At different times, growth and pyruvate kinase (PK) activity of the primary tumors and lymph node metastases were determined. Flu had a dose-dependent inhibitory effect on primary and metastatic tumors, and the inhibitory effect on growth and PK activity in metastases were higher than in primary tumors. Finally, Flu had an earlier inhibitory effect on the early appeared PK activity in metastases than in primary tumors.

Atorvastatin effect on high-density lipoprotein-associated paraoxonase activity and oxidative DNA damage

OBJECTIVE

High-density lipoprotein (HDL)-associated antioxidant paraoxonase (PON) may reduce low-density lipoprotein (LDL) oxidation and prevent atherosclerosis. The aim of this present study was to investigate the effect of the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor atorvastatin on hydrogen-peroxide-induced DNA damage by comet assay and the correlation between oxidative DNA damage and antioxidant PON activity.

METHODS

Thirteen type-II/a hyperlipidemic patients were enrolled in the study. We examined the effect of 10 mg/day atorvastatin treatment on lipid levels and the degree of DNA damage in lymphocytes separated from hyperlipidemic patients, nitric oxide (NO), thiobarbituric acid-reactive substances (TBARS), PON levels and activity.

RESULTS

After 6 months, atorvastatin treatment significantly decreased serum cholesterol and LDL-cholesterol levels. The triglyceride level did not change, and there was no significant change in the HDL cholesterol level. The visual score characteristic to the degree of DNA damage in comet assay was significantly decreased, as well as the TBARS level, while the level of NO was non-significantly increased. PON activity and the PON/HDL ratio were significantly increased after atorvastatin treatment. There was a negative correlation between DNA damage and PON activity, as well as between DNA damage and the PON/HDL ratio before and after atorvastatin treatment.

CONCLUSION

These findings show that atorvastatin treatment favorably affected the lipid profile, increasing the activity of HDL-associated PON and decreasing the cytotoxic effect of oxidative stress.

Serum cholesterols have a more important role than triglycerides in determining intima-media thickness of the common carotid artery in subjects younger than 55 years of age

OBJECTIVE

The role of serum cholesterol and triglycerides in carotid artery atherosclerosis is controversial. We measured carotid artery intima-media thickness (IMT), a marker of atherosclerosis in subjects younger than 55 years of age with a 6-fold range of serum cholesterol levels (3.93-25.03 mmol/L) and a 200-fold range of triglyceride levels (0.36-75.97 mmol/L).

METHODS

Eighty-six patients with increased serum lipid values and 30 subjects with normal lipid values were included. Serum lipids were measured after an overnight fast. High-resolution sonographic investigations of the carotid arteries of all patients were videotaped. Intima-media thickness was measured offline at 1-mm increments in the distal 10-mm segments of both common carotid arteries by a reader blinded to patient characteristics. First, IMT was compared among groups defined by their cholesterol and triglyceride levels with the use of traditional cutoff values. Next, all subjects were pooled, and general regression analysis was performed to identify significant predictors of IMT with age, body mass index, lipid values, sex, diabetes, hypertension, and smoking status as independent variables.

RESULTS

Intima-media thickness was larger in patient groups with high cholesterol levels (ie, the hypercholesterolemic and combined hyperlipidemic groups) than in the control, borderline, and isolated hypertriglyceridemic groups (P < .01). In the general multiple regression model, IMT correlated positively with total cholesterol level (beta = 0.343; P = .002) and age (beta = 0.3; P = .006) but not with triglyceride level.

CONCLUSIONS

Both the group comparisons and the general regression analysis of the pooled data suggest that hypercholesterolemia has an important role in early onset IMT changes in the common carotid artery, whereas hypertriglyceridemia does not have an appreciable role.

Effect of short term treatment with simvastatin and atorvastatin on lipids and paraoxonase activity in patients with hyperlipoproteinaemia

OBJECTIVE

High-density lipoprotein (HDL)-associated paraoxonase (PON) activity may play an important role in the inhibition of low-density lipoprotein (LDL) oxidation. Previous studies have demonstrated that serum PON activity is decreased in patients with hyperlipoproteinaemia and coronary heart disease. The study presented here examined the effect of short-term treatment with simvastatin and atorvastatin on lipids and PON activity in patients with hyperlipoproteinaemia.

RESEARCH DESIGN AND METHODS

A prospective, non-blinded, single-group, cross-over, comparative trial was performed. Following an 8-week dietary run-in period, 49 patients (23 men and 26 women, mean age: 59.8 +/- 7.9 years) with Fredrickson type IIa. and IIb. hyperlipoproteinaemias were randomized to receive either simvastatin 20 mg/day or atorvastatin 10 mg/day for 3 months. Following an 8-week washout period, patients were crossed-over to receive the other drug for a further 3 months. Serum lipids were measured and serum PON activity was determined spectrophotometrically using paraoxon as a substrate.

RESULTS

Simvastatin treatment significantly reduced serum cholesterol, LDL-cholesterol (LDL-C) and apolipoprotein (apo) B levels (p < 0.001). Atorvastatin had a more pronounced cholesterol, LDL-C- and apo B-lowering effect (p < 0.001) compared with simvastatin. Both statins also significantly reduced serum triglyceride levels (p < 0.01). Simvastatin and atorvastatin caused no significant change in the levels of HDL-cholesterol (HDL-C) and apo A1. HDL-associated PON activity did not change significantly after simvastatin therapy, but significantly increased after atorvastatin treatment (p < 0.05).

CONCLUSIONS

Short-term administration of simvastatin did not increase PON activity. Atorvastatin treatment had a favourable effect on lipid profile and increased the activity of HDL-associated PON.

The effect of micronised fenofibrate on paraoxonase activity in patients with coronary heart disease

OBJECTIVE

To evaluate the effect of micronised fenofibrate on serum paraoxonase (PON) and lipoprotein levels in coronary heart disease patients with type IIb hyperlipidemia.

PATIENTS AND METHODS

Fifty-two patients were investigated for the three-month effect of 200 mg per day micronised fenofibrate on the serum enzyme activity and concentration of PON and their relationship with serum lipids, high-density lipoprotein (HDL-C) parameters.

RESULTS

Serum paraoxonase activity was lower in CHD patients with type IIb hyperlipoproteinemia. During the three-month study it was observed that following treatment with micronised fenofibrate, serum triglyceride and cholesterol levels decreased, while HDL-C increased significantly (p<0.001). Low-density lipoprotein (p<0.05) and apolipoprotein B-100 (p<0.01) decreased, while HDL constituent apolipoprotein A-I (p<0.05) increased after micronised fenofibrate treatment. The HDL-associated paraoxonase specific activity increased significantly (p<0.05). To assess whether the increased PON activity was due to elevated HDL and apoA-I level, we standardized PON activity for HDL and apoA-I concentrations. The standardized values for HDL (PON/HDL) increased (p<0.05) while the PON/apoA-I ratio did not change significantly.

CONCLUSION

Three months of treatment with micronised fenofibrate is thought to normalize lipid profile and improve antioxidant status by increasing serum paraoxonase activity in these patients.

Serum paraoxonase activity changes in patients with Alzheimer's disease and vascular dementia

The prevalence of Alzheimer's disease (AD) and vascular dementia (VAD) increases with aging of the population. The role of lipoproteins in the pathogenesis of AD is unclear: apoE(2) offers protection and apoE(3) is neutral, while apoE(4) promotes the development of the disease. Recently, several studies have confirmed the role of oxidative stress in the pathogenesis of AD and VAD. HDL-associated paraoxonase is one of the antioxidative enzymes that may reduce LDL oxidation. In our study, we investigated the lipid parameters of the sera and the serum paraoxonase activity in patients with AD and VAD. Lipid parameters were determined by an autoanalyzer in 30 AD patients, 40 VAD patients and 40 healthy, age-matched control (C) subjects. Paraoxonase activity was measured spectrophotometrically using paraoxon as the substrate. The phenotypic distribution of paraoxonase was determined by the dual substrate method, using paraoxon and phenylacetate as substrates. In our results, we found that most of the patients with AD had the apoE(4) isoform, consistent with other studies. In the VAD and AD patients we found significantly higher total-cholesterol compared to the control group (C: 4.71 +/- 0.89, VAD: 6.3 +/- 0.8, AD: 6.52 +/- 0.7 mmol/l; p < 0.01) and LDL-cholesterol levels (C: 2.6 +/- 0.6, VAD: 3.96 +/- 0.8, AD: 3.84 +/- 0.6 mmol/l; p < 0.001). The HDL-associated antioxidant, paraoxonase activity did not differ significantly in the patient groups, but compared to the healthy control subjects, paraoxonase activity was significantly lower in both of the patient groups (C: 188 +/- 55 U/l; AD: 131 +/- 37, VAD: 151 +/- 50 l; p < 0.05). Our results suggest that the defect in HDL-associated antioxidant capacity plays a role in the pathogenesis of Alzheimer's disease and vascular dementia.

[The elastin-laminin receptor]

Elastin is a major component of the extracellular matrix. Elastin peptides derived from its degradation are present in human sera. Elastin peptides induce on fibroblasts, phagocytic cells, lymphocytes, smooth muscle cells and endothelial cells, a variety of biological effects mediated by the elastin-laminin receptor which has been demonstrated to be present on the membrane of these cells. The transduction pathway of the ELR receptor involves the activation of phospholipase C (PLC) by a pertussis toxin sensitive G-protein. PLC induces the production of inositol trisphosphate (IP3) leading to the increase of the intracellular free calcium on one hand, and of diacylglycerol (DAG) which stimulates the translocation to the membrane of PKC leading to the phosphorylation of members of the MAPK family, such as p42/p44 MAPK. Considering the multiple biological effects of ELR the elucidation of the complexity of the signaling pathways will help to better modulate it, mainly in pathological situations such as atherosclerosis.

Determination of DNA damage induced by oxidative stress in hyperlipidemic patients

In the present paper, we report data on the genotoxic properties of hydrogen peroxide in polymorphonuclear neutrophils (PMNLs) separated from normolipidemic and type II/a hyperlipidemic patients. In all, 15 hyperlipidemic patients (11 female, 4 male, mean age 54.6+/-10.25 years) were involved in the study, and 7 normolipidemic patients (5 female, 2 male, mean age 53.4+/-8.07 years) served as controls. Using the comet assay, there was a significant difference in the degree of DNA damage between the two groups. The visual score characteristic of the degree of DNA damage was 350.97+/-31.31 in the hyperlipidemic group, while it was 289.5+/-29.49 in the control group (P<0.001). In the hyperlipidemic patients, a positive correlation was found between the degree of DNA damage and the basic oxidation of PMNLs (r=0.517), and the superoxide anion production of the cells stimulated with phorbolmiristate acetate (PMA) (r=0.326) and formyl-Met-Leu-Phe (FMLP) (r=0.525) as well. There was a negative correlation between DNA damage and HDL-associated antioxidant paraoxonase (PON) activity (r=-0.469), and the PON/HDL ratio (r=-0.631). No correlation was found between the degree of DNA damage and the plasma concentration of nitric oxide (NO) (r=0.098) and thiobarbituric acid-reactive substances (TBARS) (r=0.061) in hyperlipidemic patients. Our results show that in hyperlipidemic patients there is an increase in lymphocyte DNA damage caused by oxidative stress when compared to normolipidemic individuals as demonstrated by comet assay. Decreased antioxidant capacity in hyperlipidemic patients may play a significant role in this process.

[Changes in lipid profile and paraoxonase activity in obese patients as a result of orlistat treatment]

257 patients from 33 centres were involved in a six-month study, the aim of which was to assess the effect of orlistat together with a diet. The authors examined how the treatment effected the anthropometrical and lipid parameters, extending the study to the aspect of paraoxonase activity in case of 25 patients. 44 patients dropped out during the study period due to the lack of sufficient diet compliance, whereas 3 patients had to stop the therapy because of the adverse event of flatus with discharge. On the average, the body mass of the patients decreased from 100.8 +/- 18.9 to 91.3 +/- 18.6 kg, i.e. by 9.5 kgs, while their BMI was reduced from 36.1 +/- 5.6 to 32.5 +/- 5.2 kg/m2 and the circumference of the waist changing from 119.1 +/- 20 to 108.3 +/- 15.1 cm, i.e. by 10.8 cms. The blood sugar level significantly decreased from 5.7 to 5.4, while the cholesterol concentration significantly dropped from 5.9 to 5.5, the triglyceride level being reduced from 2.4 to 2.1 mmol/l and blood pressure falling significantly from 136.6/86.9 to 129.9/81.6. All the above changes showed a significant decrease. However, the HDL-cholesterol level did not change. The serum paraoxonase activity significantly increased (143 +/- 49 vs 166 +/- 43 UL) along with the standardised values for HDL (PON/HDL), even compared to the control diet group. From the above results it may be concluded that orlistat tends to have an antioxidant effect.

Gemfibrozil increases paraoxonase activity in type 2 diabetic patients. A new hypothesis of the beneficial action of fibrates?

OBJECTIVE

The constellation of elevated triglycerides and decreased high-density lipoprotein is recognised as a risk factor for CAD and constitutes the major dyslipidemia in type 2 diabetes. The high-density lipoprotein associated paraoxonase activity can inhibit low-density lipoprotein oxidation and has an antiatherogenic effect. To determine the effect of gemfibrozil on the dyslipidemia and serum paraoxonase activity in patients with type 2 diabetes.

MATERIAL AND METHODS

Fifty-six type 2 diabetic patients with associated hypertriglyceridemia were involved. They were investigated for the effect of twice daily 600 mg of gemfibrozil on serum cholesterol, triglycerides, apolipoproteins, fibrinogen level, body mass index and glycated hemoglobin. Serum paraoxonase activity was measured spectrophotometrically.

RESULTS

After three months, it was observed that under the effect of gemfibrozil, serum triglyceride level was significantly decreased (from median: 3.46 mmol/l quartiles: q1=2.92 q3=5.28 to median 2.20 mmol/l quartiles: q1=1.79 q3=3.65; p<0.001) while protective high-density lipoprotein (from 1.02 +/- 0.22 mmol/l to 1.13 +/- 0.28 mmol/l; p=0.05) and apolipoprotein A(1) (from 1.56 +/- 0.33 g/l to 1.72 +/- 0.29; p<0.01) levels were significantly increased. Serum paraoxonase activity was found to be significantly increased (from median: 100.2 U/l quartiles: q1=60.1 q3=152.7 to median 118.7 U/l quartiles: q1=80.1 q3=171.0; p<0.001) after gemfibrozil treatment. The total cholesterol, low-density lipoprotein, apolipoprotein B, lipoprotein (a), glycated hemoglobin and fibrinogen levels were not significantly changed during the three-month treatment period. The standardized paraoxonase activity for HDL and apo A(1) were not significantly changed. Paraoxonase activity did not correlate with the concentration of glycohemoglobin and the duration of diabetes.

CONCLUSION

Twice daily administration of 600 mg of gemfibrozil is effective in type 2 diabetic patients with associated hypertriglyceridemia. It favorably lowers lipid levels, and improves antioxidant status by increasing serum paraoxonase activity.

Which parameters affect cytosolic free calcium in polymorphonuclear leukocytes of haemodialysis patients?

BACKGROUND

Cytosolic free calcium ([Ca(2+)](i)) is an important second messenger during stimulation in a wide variety of cells, including polymorphonuclear leukocytes (PMNs). Its mobilization in PMNs is altered in various diseases such as atherosclerosis and ageing. In chronic haemodialysis (HD) patients, both atherosclerosis and accelerated ageing are well known. Therefore [Ca(2+)](i) in resting PMNs of HD patients was determined along with certain parameters which might affect it, such as recombinant human erythropoietin (rHuEpo) treatment, calcium-phosphate balance, and biocompatibility of dialysis membranes.

METHODS

PMNs were separated by density centrifugation and [Ca(2+)](i) was determined by spectrofluorimetry using Quin 2/AM fluorescent dye. Laboratory parameters were determined by standard methods in clinical chemistry.

RESULTS

It was found that [Ca(2+)](i) in resting PMNs of HD patients not undergoing rHuEpo therapy was higher than that of controls. After 12-weeks of rHuEpo therapy, [Ca(2+)](i) decreased to near normal level. The role of erythropoiesis in normalization of [Ca(2+)](i) in resting PMNs was supported by PMN [Ca(2+)](i) which was elevated in patients who had low haemoglobin (<100 g/l) or haematocrit (<0.30) values. In some patients, including those receiving rHuEpo treatment, [Ca(2+)](i) remained high, suggesting a role for other parameters in increasing [Ca(2+)](i). One possible parameter might be the disturbed calcium-phosphate metabolism of chronic renal failure, because we found a strong correlation between [Ca(2+)](i) and plasma iPTH levels in HD patients (r=0.743, P<0.001). [Ca(2+)](i) was also elevated in PMNs of those patients who had either low plasma calcium or high plasma phosphate levels. PMN [Ca(2+)](i) of HD patients correlated positively with the duration of HD (r=0.671, P<0.001). However, there was no correlation between [Ca(2+)](i) and patient age. The dialysis procedure itself also transiently increased PMN [Ca(2+)](i) HD patients, independently of the type of dialysis membrane.

CONCLUSION

PMN [Ca(2+)](i) is modulated by various parameters in HD patients, including the degree of anaemia, disturbances of calcium metabolism, and duration of dialysis treatment. The elevated [Ca(2+)](i) of resting PMNs might contribute to altered functions in these cells.

Serum paraoxonase activity changes in uremic and kidney-transplanted patients

Serum paraoxonase (PON) is a high-density lipoprotein (HDL)-associated hydrolase, which inhibits low-density lipoprotein oxidation. Uremic and kidney-transplanted patients have an increased risk of atherosclerosis, to which an increased lipoprotein oxidation may contribute. The aim of our study was to determine whether the PON activity or phenotype is altered in uremic and kidney-transplanted patients, and to compare the values with those of healthy controls. 117 uremic patients on long-term hemodialysis treatment, 115 renal-transplanted patients, and 110 healthy controls were involved in the study. The PON activity was significantly reduced in the uremic patients compared to controls (PON 101.36+/-30. 12 vs. control 188.05+/-58.96 U/ml; p < 0.001), while in kidney-transplanted patients the values were almost identical to those of controls (PON 161.5+/-35.39 U/ml). The different immunosuppressive drug combinations did not influence PON activity. To assess whether the altered PON activity was due to a decrease HDL level, we standardized the enzyme activity for the HDL concentration (PON/HDL ratio). We found that the standardized enzyme activity was lower in the uremic (102.7+/-54.8) and kidney-transplanted patients (144.5+/-32.7) when compared to controls (194.5+/-94.5; p < 0.001). The phenotypic distribution of PON in uremic, renal transplant and control patients are as follows: AA 66.67, 56.48 and 66.67%; AB 31. 62, 33.3 and 26.67%; BB 1.71, 10.19 and 6.67%. We conclude that the decreased PON/HDL and PON/apoA-1 ratios may lead to a reduction in the antioxidant capacity of HDL, which might contribute to the accelerated development of atherosclerosis in uremic and kidney-transplanted patients.

Altered signal pathway in granulocytes from patients with hypercholesterolemia

In the present study the signal transduction of the formyl-Met-Leu-Phe receptor was studied in granulocytes obtained from control subjects and patients with elevated low density lipoprotein levels. According to our results, 10 nm formyl-Met-Leu-Phe in control cells activates phospholipase C inducing a pronounced inositol phosphate production followed by a Ca(2+) signal from intracellular pools. The pertussis toxin-sensitive O(2)(-) generation and leukotriene synthesis were moderate. In contrast, in granulocytes from hypercholesterolemic patients, formyl-Met-Leu-Phe triggered an intensive pertussis toxin-insensitive oxidative burst and leukotriene synthesis. The inositol trisphosphate and Ca(2+) signals were decreased significantly in granulocytes of hypercholesterolemic patients and seem to be dependent on the extracellular Ca(2+) content. Furthermore, in the resting granulocytes of hypercholesterolemic patients the [Ca(2+)]i and the membrane-bound protein kinase C activity were higher than in controls, the time of normalization after the low Ca(2+) signal was delayed, while the membrane fluidity was decreased. Our results suggest that in these ex vivo experiments, the high level of circulating low density lipoprotein in patients can affect the membrane composition of granulocytes leading to altered signal transduction by the formyl-Met-Leu-Phe receptor, to altered Ca(2+) pump-activity, and protein kinase C translocation.

The serum paraoxonase activity in patients with chronic renal failure and hyperlipidemia

Human serum paraoxonase is physically associated with an apolipoprotein (Apo-A1) and clusterin-containing high-density lipoprotein (HDL) and prevents low-density lipoprotein from lipid peroxidation. The aim of our study was to determine whether paraoxonase activity or phenotype is altered in patients with chronic renal failure and in hyperlipidemic subjects without renal insufficiency and to compare the values with those of healthy controls. We investigated the serum paraoxonase activity and polymorphism in 119 hemodialyzed uremic patients, 107 patients with primary hyperlipoproteinemia, and in 110 healthy control subjects. The serum paraoxonase activity was significantly decreased both in hyperlipidemic (p < 0.01) and uremic patients (p < 0.001) as compared with controls. On comparison, the serum paraoxonase activity was significantly lower (p < 0.001) in uremic than in hyperlipoproteinemic patients. The HDL and Apo-A1 levels were as follows: uremic < hyperlipidemic < control. To assess whether the observed reduction in paraoxonase activity was due to HDL and Apo-A1 level decreases, we standardized the enzyme activity for HDL and Apo-A1 concentrations. We found that the standardized paraoxonase activity (paraoxonase/HDL ratio) was also lower in the uremic patients (103.3 +/- 69.5) as compared with hyperlipidemic patients (137.64 +/- 81.0) and controls (194.45 +/- 94.45). The standardized values for Apo-A1 showed a similar tendency: paraoxonase/Apo-A1 ratio in uremic patients 89.64 +/- 47.8, in hyperlipidemic patients 128.12 +/- 69.83, and in controls 161.40 +/- 47.35. The phenotypic distribution of paraoxonase (AA, AB, BB) did not change significantly in the patient groups. These results suggest that HDL concentration and phenotypic distribution of paraoxonase may not be the only determining factors, but that other as yet undetermined factors could be involved in the enzyme activity changes.

[Granulocyte function and lipid peroxidation in untreated patients with hyperlipoproteinemia]

The fatty acid composition in free fatty acid and phospholipid fraction of plasma in untreated mildly hyperlipidemic patients were determined. The general trend was an increase in saturation in both free and phospholipid fractions of plasma in patients compared with that of healthy controls. Furthermore, arachidonic acid, precursor of formation of prostaglandins and leukotrienes was detected in significantly lower amount in plasma of mildly and untreated hyperlipidemic patients. These fatty acid abnormalities were connected with the increased lipidperoxidation in plasma lipids and in both resting and stimulated granulocytes.

[In vitro study of endothelium-dependent relaxation and contraction of human atherosclerotic femoral artery]

According to present knowledge, altered arterial reactivity associated with hypertension, atherosclerosis and hypercholesterolemia is related to impaired release of endothelial derived relaxing factor (EDRF). Impaired relaxation followed by enhanced vasoconstriction leads to a well known clinical entities such as unstable angina, acut myocardial infarction. Impairment of EDRF may also account for smooth muscle cell proliferation and migration. Aim of present study was to examine the endothelial dependent response during in vitro conditions in human femoral arteries taken from bypass operation and leg amputation. Examining the contractility, the effect was modulated with nifedipin, EDTA and pertussis toxin, respectively. Endothelium dependent relaxation to acethylcholin and histamine were markedly diminished, while those to calcium ionophore were maintained throughout the study. These results suggest that at least two or more receptor-coupled system may be involved in generation of EDRF. However, direct relaxation of femoral artery to nitrovasodilatators (nitroglycerine) were comparable between control and atherosclerotic artery. Another striking change in atherosclerotic artery was the increased sensitivity to the vasoconstrictions. To eluciadate to exact biochemical mechanism underlying the endothelial dysfunction may help to develop a new vasodilatator drug.

Neutrophils obtained from obliterative atherosclerotic patients exhibit enhanced resting respiratory burst and increased degranulation in response to various stimuli

Tissue destruction in atherosclerosis is partly due to uncontrolled protease and oxygen radical release. In this study we investigated the release of elastase and myeloperoxidase, as well as the production of reactive oxygen species by polymorphonuclear leukocytes (PMNLs) obtained from patients with obliterative atherosclerotic of the lower legs. In addition we measured the plasma concentration of xanthine oxidase. PMNLs of atherosclerotic patients have a greater ability to increase elastase and myeloperoxidase release after their stimulation with formyl-methionin-leucyl-phenylalanin (fMLP) and calcium ionophore, A23187, independently of their age, than PMNLs of healthy middle-aged subjects. Similarly to healthy elderly subjects there was an increased superoxide anion (O2-) production under basal condition in both atherosclerotic patient age-groups. The activation of PMNLs with fMLP and A23187 enhanced O2- formation both in healthy subjects and in patients with atherosclerotic disease of the lower legs, however the increase was significantly less in the latter group. No biochemical parameters showed significant correlation with patient's risk factors, however myeloperoxidase production was significantly higher in less severe stage of the disease (P < 0.05). We found that patients with atherosclerotic disease of the lower legs have higher plasma xanthine oxidase level than control subjects. This study indicates an other piece of evidence suggesting the activation and involvement of neutrophils in the pathogenesis of atherosclerosis of the lower legs. The similar tendencies in the reactivity of neutrophils during aging and in atherosclerosis suggest that atherosclerosis may be an early aging process.

Alteration of lymphocyte membrane phospholipids and intracellular free calcium concentrations in hyperlipidemic subjects

Hypercholesterolemia has been proposed to influence cell functions via changes in membrane composition. The aim of the present study was to determine whether the membrane phospholipid composition of human lymphocytes is modified in hypercholesterolemia and whether these changes are accompanied by functional modifications. The phospholipid fatty acid contents and intracellular free calcium concentrations were determined in peripheral blood lymphocytes from 13 subjects with serum total cholesterol levels ranging from 4.6 to 8.8 mmol/l. The spontaneous basal rate of thymidine incorporation in lymphocyte of hypercholesterolemic individuals increased, while its relative stimulation by ConA was less effective. Important changes in membrane lipid composition, consisting mainly of decrease of the mass of phospholipids, and of associated polyunsaturated fatty acids were observed in hypercholesterolemia. In contrast, the cell cholesterol content was significantly increased. The intracellular free calcium concentration was enhanced and strongly associated with circulating cholesterol levels, cell cholesterol content and phospholipid fatty acids. These results indicate that hypercholesterolemia is accompanied by profound changes in lymphocyte membrane lipid composition and Ca(2+) handling.

[Serum elastin peptide concentration and human leukocyte elastase/antiproteinase balance in peripheral obstructive atherosclerosis]

In some pathological states such as therosclerosis tissue destruction may be accelerated due to uncontrolled protease release of polymorphonuclear leukocytes and other events such as decreased concentration and/or the inactivation of main protease inhibitor molecules in the serum. In this study, the authors measured the elastase release of polymorphonuclear leukocytes which increased in atherosclerosis independently of the patients aged compared to healthy young subjects. These findings were similar to the response of polymorphonuclear leukocytes separated from healthy elderly subjects. Simultaneously, the main plasma proteinase inhibitors such as alpha-1-antitrypsin and alpha-2-macroglobulin in healthy and atherosclerotic subjects were determined. alpha-1-antitrypsin did not decrease significantly, whereas alpha-2-macroglobulin did in sera of atherosclerotic patients compared to age matched subjects (p < 0.05). In contrast, the activity of porcine pancreatic elastase was more effectively neutralized by the plasma obtained from healthy subjects suggesting diminished antiprotease activity of sera obtained from patients. The authors concluded that increased elastase release and decreased antiproteinase activity should be considered in atherosclerotic arterial wall damage. The similarity of the results in aged and therosclerotic subjects suggests that arteriosclerosis is an earlier aging process.

Effects of synthesized elastin peptides on human leukocytes

It is well demonstrated that various peptides derived from elastin are biologically active. The hexapeptide (Val-Gly-Val-Ala-Pro-Gly; VI) as well as elastin peptides were demonstrated to be chemotactic for fibroblasts, while kappa-elastin had marked biological effects on human PMNLs. The aim of our present work was to synthesize various elastin peptides and compare their action to that of kappa-elastin and this hexapeptide. The results indicate that the hexapeptide (Val-Gly-Val-Ala-Pro-Gly) and the two other synthesized hexapeptides (Pro-Gly-Val-Gly-Val-Ala; III and Val-Gly-Val-Gly-Val-Ala; IV) had very similar and specific effects on intracellular free calcium metabolism, on superoxide anion production and elastase release. The other peptides had no effects on these parameters, except a tripeptide (Val-Gly-Val; V) on superoxide anion production. Moreover, the effect of the hexapeptides (III and VI) could be abolished by Pertussis toxin preincubation. All peptides had very similar stimulating effects on H2O2 production and myeloperoxidase release. We conclude that most probably the peptide size and conformation, as well as peptide composition play a role in the biological effects of these peptides, through specific receptors on PMNLs surface.

Age-related changes in signal transduction. Implications for neuronal transmission and potential for drug intervention

Problems associated with aging will become one of the leading health dilemmas of the next century. Age-associated diseases, including those affecting the neuronal system, are increasing in frequency. Age-related deficiencies in the brain result in impaired motor functions, sleep, behaviour and cognitive functions. Good functioning of the brain is based on the communication between neurons, by means of signal sending and processing. Neuronal transmission is a very complex phenomenon which involves neuromediator receptors, ion channels and various signal transduction systems. Aging is associated with modification of many brain neurotransmitter and second messenger systems directly involved in signal transduction. Thus, signal transduction events that are deficient in the aged include calcium mobilisation, phosphatidylinositol breakdown, cyclic nucleotides formation, accumulation of proto-oncogene transcripts and synthesis of new proteins, such as certain neurotransmitters. Other events in signal transduction, such as protein tyrosine kinase activity, G-protein structure and function and receptor-G-protein coupling, have not been studied in great detail as yet. Alterations in these various intracellular signalling events may fundamentally influence the functional activity of neurons, and, in consequence, play an important role in the age-dependent alterations of brain functions. Future studies are needed to better understand the molecular basis and the importance of signal transduction changes with aging. Such knowledge will certainly lead to design of better drugs for the prevention or treatment of age-related deficiencies or diseases, such as Parkinson's disease or Alzheimer's disease.

Peripheral blood lymphocytes display reduced K+ channel activity in aged humans

Steady-state parameters of whole-cell K+ current have been determined in human peripheral blood lymphocytes of young (20-50 y.) and elderly (> 90 y.) volunteers by patch-clamp. The magnitude and voltage dependence of the K+ conductance were similar in both lymphocyte populations. The midpoint of steady-state inactivation was -53.3 +/- 2.3 mV for lymphocyte population of young individuals and -65.0 +/- 3.0 mV for that of elderly, showing a significant shift to hyperpolarized potentials. The peak of the steady-state open probability of the K+ channels was decreased and shifted to depolarized potentials by approx. 12.5 mV for lymphocytes of elderly donors. It is suggested that the observed differences in the K+ current parameters may be at least partly responsible for the impaired responsiveness of elderly lymphocytes to proliferative stimuli.

Age-dependent alterations of human recombinant GM-CSF effects on human granulocytes

The granulocyte-macrophage colony stimulating factor (GM-CSF) is an important in vivo regulator of granulopoiesis and neutrophil functions. It is well-known that the immune response and the transmembrane signalling in immune cells change with aging. We wished to elucidate the effects of GM-CSF in itself and in priming the activities of other inflammatory agents on neutrophils of elderly persons. Neutrophils of 20 healthy elderly (aged 60-90 years) and 20 healthy young (aged 20-25 years) subjects were studied for superoxide anion production, intracellular free calcium mobilization, antibody dependent cellular cytotoxicity (ADCC) and intracellular killing activities. It was found that GM-CSF is unable to prime neutrophils of elderly subjects to the action of FMLP, metenkephalin or opsonized zymosan. By the use of Pertussis toxin and H7 it was demonstrated that a different signal transduction pathway in neutrophils of elderly subjects is activated by GM-CSF or FMLP if compared to that of young subjects. These results suggest that the lack of priming could contribute to the greater susceptibility of the elderly to infections and that the change of the signal transduction mechanism in neutrophils of elderly subjects might partly explain this phenomenon.

Age-dependent changes in transmembrane signalling: identification of G proteins in human lymphocytes and polymorphonuclear leukocytes

In human neutrophils (PMNLs) we found that in the elderly IP3 formation was significantly decreased compared to that of young subjects. For FMLP receptor binding affinity and number no measurable differences occurred upon ageing, studying both the low or the high affinity receptors. The amount of ADP-ribosylated G proteins, catalysed by pertussis toxin (PT) or cholera toxin (CT), was significantly increased in PMNLs of the elderly. In lymphocytes, the PT-catalysed ADP ribosylation of G proteins was also increased with ageing, while the CT-catalysed ribosylation was decreased. The autoradiogram of [32P]ADP-ribosylated proteins by CT in lymphocytes of young individuals showed a major polypeptide of 40,000 M(r). In contrast, in lymphocytes of the elderly, the major polypeptide was 45,000 M(r). In PMNLs, CT labelled quite strongly the 45,000 M(r) band, mainly in the elderly. When PT was used, no age-related pattern changes could be demonstrated, while differences could be observed between the two types of cells. The use of antiserum P680 (G alpha common) showed no age-related pattern changes, while the intensity of the labelled proteins varies with age and cell type. The antiserum U46 (Go alpha) could identify in lymphocytes of young subjects two polypeptides 68,000 and 41,000 M(r). The prominent polypeptide in lymphocytes of the elderly was the 70,000 M(r) and no other polypeptides could be recognized. In PMNLs of young subjects the U46 and serum identified a range of species. In PMNLs of the elderly all these bands were weakly labelled. The present data indicate changes in the pattern and the quantity of G proteins in lymphocytes and PMNLs of elderly subjects.

Transmembrane signaling changes with aging

Altered immune response and transmembrane signaling with aging has previously been demonstrated. The aim of the present study was to characterize PMNLs and lymphocyte G proteins and to determine whether their relative amounts are altered with aging. First we studied the effects of FMLP on PMNLs IP3 formation. It was found that in any group of elderly the PMNLs IP3 formation was significantly decreased compared to that of young subjects. In FMLP receptor binding affinity no measurable difference exists in either low- or high-affinity FMLP receptors. The autoradiogram of 32P-ADP-ribosylated proteins by CT in lymphocytes of young individuals showed a major polypeptide of 40 kDa, and two much less prevalent components of 52 and 45 kDa. In contrast, in lymphocytes of elderly subjects the major polypeptide was 45 kDa, and the two others were very weakly labeled. In PMNLs, CT labeled the 45-kDa band quite strongly, mainly in the elderly, and the 52- and 40-kDa bands were very weakly labeled, mainly in young subjects. When PT was used, no age-related pattern changes could be demonstrated, while differences could be observed between the two types of cells.

[The accidents and complications of laparoscopy. A review of 8,915 cases]

Complications occurring in 8,915 laparoscopies done during 1957-1991 are analyzed. Complications were classified as major or minor, according to the need of surgical intervention for their management, and also in relation to pneumoperitoneum, introduction of the laparoscope, during the examination or after laparoscopy. The total number of major accidents was 54 (0.60%). Half of them as a consequence of the instrumentation or of liver biopsy. There were 442 minor complications (4.96%). Mortality included 10 patients (0.11%) as a sequel of uncontrolled haemorrhage, 5 of them after liver biopsy. The complications of laparoscopy cannot be ignored; as all invasive techniques it may have a risk, even in the most expert hands. Half of the major accidents and of the mortality were due to complications from liver biopsy.

Superoxide anion production and intracellular free calcium levels in resting and stimulated polymorphonuclear leukocytes obtained from healthy and arteriosclerotic subjects of various ages

It has been established that phagocytic cells are integral components of advanced arteriosclerotic plaques but their role in plaque formation remains unclear. Therefore, toxic agents, such as superoxide anion produced by polymorphonuclear leukocytes (PMNLs) were studied in a clinically defined group of arteriosclerotic patients suffering from obliterative arteriosclerosis of the lower legs. Owing to a close correlation between O2- generation and calcium, the intracellular free calcium concentrations of PMNLs were measured in a resting state and after stimulation with various agents, for example, opsonized zymosan (OZ), the chemotactic peptide f-met-leu-phe (FMLP), and the calcium ionophore A23187. Healthy aged-matched controls were employed. The patients were divided into two age groups: 30-59 years and 60-80 years. We found that in the younger group of arteriosclerotic patients, superoxide anion production and intracellular free calcium concentrations were increased even in the resting state, and only a slight increase was observed after stimulation compared with healthy controls. Granulocyte responses seemed to be similar, independent of the patient's age, to those found in healthy elderly subjects. Arteriosclerosis appears to be associated with an early aging process expressing marked alterations that are greater than those associated with normal aging.

Low C3 in cirrhotic ascites predisposes to spontaneous bacterial peritonitis

The risk of developing spontaneous bacterial peritonitis (SBP) in relation to the concentration of C3 in ascitic fluid (AF) has been studied prospectively in 33 patients with cirrhosis of the liver, seven of whom had one or more episodes of SBP during hospitalization. C3 concentrations in the AF of patients who developed infection (9.0 +/- 2.67 mg/dl) were significantly lower than in those who did not (18.26 +/- 8.11 mg/dl) (P less than 0.01). C4 concentrations were similar in both groups. A direct correlation was found between AF C3 and total protein concentrations (P less than 0.001). We conclude that a low C3 concentration in AF may predispose to SBP.

Effect of sulindac on prostaglandin excretion and renal function in cirrhotic patients with ascites

The effect of sulindac, a nonsteroidal anti-inflammatory drug, on renal prostaglandin synthesis and renal function variables was investigated in six cirrhotic patients with tense ascites and marked sodium retention. We studied serum thromboxane (TXB2) production, urinary prostaglandin excretion (6-keto-prostaglandin F1 alpha and TXB2) and renal function before and after administration of a therapeutic dose of sulindac (400 mg). After treatment, no significant changes were observed in urinary prostaglandin excretion, serum creatinine concentration, urine volume, or urinary sodium and creatinine clearance, whereas the serum TXB2 concentration was reduced in 89%. In five patients systemic prostaglandins were inhibited, but renal excretion remained unchallenged. However, one patient showed marked reduction of urinary prostaglandins associated with a depression of renal function. The study suggests that sulindac could be a safe substitute for other nonsteroidal anti-inflammatory drugs in cirrhotic patients with ascites. Further pharmacological trials seem to be warranted.

A double-quenching method for studying protein dynamics: separation of the fluorescence quenching parameters characteristic of solvent-exposed and solvent-masked fluorophors

A novel experimental method, suitable for separate analysis of the quenching parameters characteristic of solvent-exposed and solvent-masked fluorophors of macromolecules, is described. The method is based on the modified Stern-Volmer analysis and requires simultaneous application of two kinds of quencher: one that can selectively quench the emission of exposed fluorophors (e.g., ionic quenchers) and another that is nonselective (e.g., oxygen or, in many cases, acrylamide), capable of quenching the fluorescence of both exposed and masked groups. In order to examine the accuracy of the model, a computer simulation was performed. The results showed that the errors are comparable to those arising from the conventional quenching experiments. The method is applicable to phosphorescence quenching as well and is extendable to time-resolved measurements (by replacing fluorescence intensities with lifetimes). The method was applied to resolve the quenching parameters of lysozyme fluorescence by the use of iodide as selective and acrylamide as nonselective quenchers. The determination of the acrylamide quenching constant associated with the internal fluorophor, Trp-108 (Kq = 3.5 M-1), permits specific studies on the dynamics of internal regions of the protein. The quenching constant determined for the more exposed residue Trp-62 (Kq = 1.6 M-1) provides local information about the surface independent of the electrostatic effects observed when an ionic quencher is used.

Dynamic interaction between functional groups in the active site of glycogen phosphorylase b

The quenching of coenzyme fluorescence in glycogen phosphorylase b is reinvestigated. Data with anionic quenchers show deviations from the original Stern-Volmer kinetics. A kinetic analysis based on measured lifetime data indicates a collisional quenching process, which is, however, not diffusion-controlled. It is proposed, that the quenching takes place primarily by enzyme-bound quencher species. The observed inhibition of the enzyme reaction by I- and IO-3 is consistent with this hypothesis. The inhibition pattern and spectral investigation refer to a true competition with the substrate, glucose-1-phosphate. So, this dynamic quenching can be regarded as an indicator of rapid conformational fluctuations which bring the two important active-site groups in contact. Effect of ligand binding on the quenching of coenzyme fluorescence should also be revaluated according to these results.