Spermidine influence on the nitric oxide synthase and arginase activity relationship during experimentally induced seizures.

Nitric oxide (NO), a potential candidate for a modulator of convulsive activity, is a mediator in several pathological events in the central nervous system. The polyamines, spermidine (Spd) and spermine, are neuromodulators influencing the metabolism of L-arginine and NO production. Here we examined the effects of Spd on NO production and arginase activity during convulsions induced by pentylenetetrazol (PTZ). Male Wistar rats were allocated into four experimental groups of 8 animals each and received the following treatments: I (control)--saline, intraperitoneally (i.p.); II (PTZ)--seizures induced by pentylenetetrazol (100mg/kg bw i.p); III (Spd)--Spd (1 mg/kg bw i.p.) 50 min before PTZ application; IV (Mid)--antiepileptic Midazolam (100 mg/kg bw) 45 min before PTZ. In brain cortex, striatum, hippocampus, cerebellum, and brainstem homogenates, nitrite + nitrate levels and arginase activity were determined. Spermidine showed proepileptic effects. shortening seizure latency and inducing a more profound increase of NO production than PTZ in all brain structures. PTZ reduced arginase activity, whereas Spd pretreatment increased enzyme activity, with the most profound effects in cerebellum and brainstem. The results point out the importance of polyamine and arginine metabolism in the brain during seizures, suggesting a regulatory role for polyamines and arginase in NO production.

Meta-analysis: antioxidant supplements for liver diseases - the Cochrane Hepato-Biliary Group.

BACKGROUND: Several liver diseases have been associated with oxidative stress. Accordingly, antioxidants have been suggested as potential therapeutics for various liver diseases. The evidence supporting these suggestions is equivocal. AIM: To assess the benefits and harms of antioxidant supplements for patients with liver diseases. METHODS: We identified trials through electronic and manual searches until August 2009. We included randomized trials comparing antioxidant supplements (beta-carotene, vitamin A, C, E and selenium) vs. placebo or no intervention for autoimmune liver diseases, viral hepatitis, alcoholic liver disease and cirrhosis (any aetiology). Random-effects and fixed-effect meta-analyses were conducted. Results were presented as relative risks (RR), or mean difference (MD), both with 95% confidence intervals (CI). RESULTS: Twenty randomized trials with 1225 participants were included. The trials assessed beta-carotene (3 trials), vitamin A (2 trials), vitamin C (9 trials), vitamin E (15 trials) and selenium (8 trials). The majority of the trials had high risk of bias and showed heterogeneity. Overall, the assessed antioxidant supplements had no significant effect on all-cause mortality [relative risk (RR) 0.84, 95% confidence interval (CI) 0.60-1.19, I(2) = 0%] or liver-related mortality (RR 0.89, 95% CI 0.39-2.05, I(2) = 37%). Stratification according to the type of liver disease assessed did not affect the conclusions. Antioxidant supplements significantly increased the activity of gamma glutamyl transpeptidase (MD 24.21 IU/L, 95% CI 6.67-41.75, I(2) = 0%). CONCLUSIONS: We found no evidence to support or refute antioxidant supplements in patients with liver disease. Antioxidant supplements may increase liver enzymes.

Does polyamine oxidase activity influence the oxidative metabolism of children who suffer of diabetes mellitus?

Diabetes mellitus is a metabolic disease characterized by inadequate secretion of insulin. Polyamine oxidase (PAO), a FAD-containing enzyme is involved in the biodegradation of Sp and Spd, catalyzing the oxidative deamination of Sp and Spd, resulting in production of ammonia (NH(3)), corresponding amino aldehydes and H(2)O(2). Malondialdehyde (MDA) and acrolein (CH2=CHCHO), potentially toxic agents, which induce oxidative stress in mammalian cells, are then spontaneously formed from aminoaldehydes. The main signs of oxidative stress in diabetic children were the values of HbA1c and MDA levels. Polyamines have an insulin-like action. Antiglycation property of spermine and spermidine has been recently confirmed. There are no data in the literature about plasma polyamine oxidase (PAO) activities in children with type 1 diabetes. The idea of this study was to evaluate the polyamine metabolism through the estimation of polyamine oxidase activity. We have study children with newly diagnosed type 1 diabetes mellitus (n = 35, age group of 5-16 years, as well as age-matched healthy control subjects (n = 25). The biochemical investigations were done on diabetic children who have the pathological values of glucose (9.11-17.33 mmol/l) and glycosylated Hb (7.57-14.49% HbA(1c)). The children in the control group have referent values of glucose and glycated hemoglobin (4.11-5.84 mmol/L and HbA(1c) 4.22-6.81% of the total Hb. Glucose levels in blood plasma and glycosylated hemoglobin in erythrocythes hemolysates (HbA1c) were measured by using standard laboratory methods. PAO activity in venous blood plasma and the amount of malondialdehyde (MDA) were measured by the spectrophotometric methods. PAO activity, glycemia, HbA1c and MDA were significantly increased in diabetic children compared to the control subjects. PAO activity in children with type 1 diabetes mellitus was very high. The findings of higher blood HbA(1C) and MDA levels confirm the presence of oxidant stress in children with type 1 diabetes mellitus and demonstrate that PAO activity may participate in these circumstances.

Metabolic correlations of glucocorticoids and polyamines in inflammation and apoptosis.

Glucocorticoid hormones (GC) are essential in all aspects of human health and disease. Their anti-inflammatory and immunosuppressive properties are reasons for therapeutic application in several diseases. GC suppress immune activation and uncontrolled overproduction and release of cytokines. GC inhibit the release of pro-inflammatory cytokines and stimulate the production of anti-inflammatory cytokines. Investigation of GC's mechanism of action, suggested that polyamines (PA) may act as mediators or messengers of their effects. Beside glucocorticoids, spermine (Spm) is one of endogenous inhibitors of cytokine production. There are many similarities in the metabolic actions of GC and PA. The major mechanism of GC effects involves the regulation of gene expression. PA are essential for maintaining higher order organization of chromatin in vivo. Spermidine and Spm stabilize chromatin and nuclear enzymes, due to their ability to form complexes with negatively charged groups on DNA, RNA and proteins. Also, there is an increasing body of evidence that GC and PA change the chromatin structure especially through acetylation and deacetylation of histones. GC display potent immunomodulatory activities, including the ability to induce T and B lymphocyte apoptosis, mediated via production of reactive oxygen species (ROS) in the mitochondrial pathway. The by-products of PA catabolic pathways (hydrogen peroxide, amino aldehydes, acrolein) produce ROS, well-known cytotoxic agents involved in programmed cell death (PCD) or apoptosis. This review is an attempt in the better understanding of relation between GC and PA, naturally occurring compounds of all eukaryotic cells, anti-inflammatory and apoptotic agents in physiological and pathological conditions connected to oxidative stress or PCD.

Arginase activity and magnesium levels in blood of children with diabetes mellitus.

Under physiological conditions insulin controls the metabolism of carbohydrates, lipids and proteins. Diabetes mellitus is a metabolic disease characterized by a disturbance in the intermediary metabolism of glucose and glucose-induced insulin release. Arginase (L-arginine amidinohydrolase, EC 3.5.3.1) modulates nitric oxide synthase activity by regulating intracellular L-arginine availability. In diabetes mellitus, a decrease in nitric oxide bioavailability is a central mechanism for endothelial dysfunction. The aim of our study was to assess arginase activity in the blood of children with diabetes mellitus. Blood arginase activity, serum glucose (14.155 +/- 4.197 mmol/L; p < .001) and blood HbA1c (11.222 +/- 3.186 %; p < .001), were significantly higher in diabetic children than in healthy controls, whereas the magnesium (Mg2+) level, a cofactor of many enzymes, was significantly lower (0.681 +/- 0.104 micromol; p < .001). In diabetic children, arginase activity, hyperglycemia (r = 0.143), and the HbA1, level (r = 0.381) showed a positive correlation between but a negative correlation between Mg2+ and arginase activity (r= -0.206). The higher arginase activity and the lower Mg2+' levels in diabetic children could be a consequence of reduced insulin action and increased protein catabolic processes in these pathophysiological conditions. The inverse directions of arginase activity and serum Mg2+ levels are in agreement with this concept.

Microalbuminuria in children with vesicoureteral reflux.

Vesicoureteral reflux (VUR) is a common congenital anomaly of the urinary tract that may be inherited. Reflux of infected urine may cause scarring in susceptible kidneys with the potential to compromise renal function. The aim of the study was to evaluate the possible influence of different grades of VUR on glomerular damage using microalbuminuria as a parameter. Children with VUR detected by voiding cystourethrography (VCUG) were investigated. According to the grade of VUR, patients were separated into three groups. The first group included 12 children with VUR grade I-II. The second group consisted of 12 children with grade III of VUR. Patients with VUR grade IV-V (n = 11) were members of the third group. The control group consisted of 17 healthy children. Microalbuminuria was examined in samples of morning urine specimens using a microalbumin/creatinine reagent kit. Serum urea, creatinine levels and creatinine clearance (CCR) were measured as markers of renal function. The mean value of microalbumin excretion in the third group showed a statistically significant increase (p < 0.001) compared to all other groups. CCR in the third group was statistically significantly decreased (p < 0.05) in comparison to the group of healthy children. There were no statistically significant changes of microalbumin excretion and CCR in the first and second group compared to control values. We discussed the presence of microalbuminuria and decrease of CCR in children with high grade of VUR as a possible consequence of retrograde urine flow (intrarenal reflux), glomerulosclerosis, and consecutive hyperfiltration.

Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases.

BACKGROUND: Animal and physiological research as well as observational studies suggest that antioxidant supplements may improve survival. OBJECTIVES: To assess the effect of antioxidant supplements on mortality in primary or secondary prevention randomised clinical trials. SEARCH STRATEGY: We searched The Cochrane Library (Issue 3, 2005), MEDLINE (1966 to October 2005), EMBASE (1985 to October 2005), and the Science Citation Index Expanded (1945 to October 2005). We scanned bibliographies of relevant publications and wrote to pharmaceutical companies for additional trials. SELECTION CRITERIA: We included all primary and secondary prevention randomised clinical trials on antioxidant supplements (beta-carotene, vitamin A, vitamin C, vitamin E, and selenium) versus placebo or no intervention. Included participants were either healthy (primary prevention trials) or had any disease (secondary prevention trials). DATA COLLECTION AND ANALYSIS: Three authors extracted data. Trials with adequate randomisation, blinding, and follow-up were classified as having a low risk of bias. Random-effects and fixed-effect meta-analyses were performed. Random-effects meta-regression analyses were performed to assess sources of intertrial heterogeneity. MAIN RESULTS: Sixty-seven randomised trials with 232,550 participants were included. Forty-seven trials including 180,938 participants had low risk of bias. Twenty-one trials included 164,439 healthy participants. Forty-six trials included 68111 participants with various diseases (gastrointestinal, cardiovascular, neurological, ocular, dermatological, rheumatoid, renal, endocrinological, or unspecified). Overall, the antioxidant supplements had no significant effect on mortality in a random-effects meta-analysis (relative risk [RR] 1.02, 95% confidence interval [CI] 0.99 to 1.06), but significantly increased mortality in a fixed-effect model (RR 1.04, 95% CI 1.02 to 1.06). In meta-regression analysis, the risk of bias and type of antioxidant supplement were the only significant predictors of intertrial heterogeneity. In the trials with a low risk of bias, the antioxidant supplements significantly increased mortality (RR 1.05, 95% CI 1.02 to 1.08). When the different antioxidants were assessed separately, analyses including trials with a low risk of bias and excluding selenium trials found significantly increased mortality by vitamin A (RR 1.16, 95% CI 1.10 to 1.24), beta-carotene (RR 1.07, 95% CI 1.02 to 1.11), and vitamin E (RR 1.04, 95% CI 1.01 to 1.07), but no significant detrimental effect of vitamin C (RR 1.06, 95% CI 0.94 to 1.20). Low-bias risk trials on selenium found no significant effect on mortality (RR 0.91, 95% CI 0.76 to 1.09). AUTHORS' CONCLUSIONS: We found no evidence to support antioxidant supplements for primary or secondary prevention. Vitamin A, beta-carotene, and vitamin E may increase mortality. Future randomised trials could evaluate the potential effects of vitamin C and selenium for primary and secondary prevention. Such trials should be closely monitored for potential harmful effects. Antioxidant supplements need to be considered medicinal products and should undergo sufficient evaluation before marketing.

Altered degradation of circulating nucleic acids and oligonucleotides in diabetic patients.

Foreign, infection-associated or endogenously generated circulating nucleotide motifs may represent the critical determinants for the activation of the Toll-like receptors (TLRs), leading to immune stimulation and cytokine secretion. The importance of circulating nucleases is to destroy nucleic acids and oligonucleotides in the blood stream and during cell entry. Patients with juvenile insulin-dependent diabetes, adult patients with insulin-dependent diabetes and adult patients with type 2 diabetes were allocated to the study, together with the age-matched control subjects. Plasma RNase and nuclease activity were examined, in relation to different substrates-TLRs response modifiers, and circulating RNA and oligonucleotides were isolated. The fall in enzyme activity in plasma was obtained for rRNA, poly(C), poly(U), poly(I:C), poly(A:U) and CpG, especially in juvenile diabetics. In order to test the non-enzymatic glycation, commercial RNase (E.C.3.1.27.5) and control plasma samples were incubated with increasing glucose concentrations (5, 10, 20 and 50 mmol/l). The fall of enzyme activity was expressed more significantly in control plasma samples than for the commercial enzyme. Total amount of purified plasma RNA and oligonucleotides was significantly higher in diabetic patients, especially in juvenile diabetics. The increase in the concentration of nucleotides corresponded to the peak absorbance at 270 nm, similar to polyC. The electrophoretic bands shared similar characteristics between controls and each type of diabetic patients, except that the bands were more expressed in diabetic patients. Decreased RNase activity and related increase of circulating oligonucleotides may favor the increase of nucleic acid "danger motifs", leading to TLRs activation.

Systematic review: primary and secondary prevention of gastrointestinal cancers with antioxidant supplements.

BACKGROUND: The evidence on whether antioxidant supplements prevent gastrointestinal cancers is contradictory. AIM: To assess the beneficial and harmful effects of antioxidant supplements in preventing gastrointestinal cancers. METHODS: Using the Cochrane Collaboration methodology, we reviewed the randomized trials comparing antioxidant supplements with placebo or no intervention on the occurrence of gastrointestinal cancers. We searched electronic databases and reference lists until October, 2007. Our outcome measures were gastrointestinal cancers, overall mortality and adverse events. Outcomes were reported as relative risks (RR) with 95% confidence intervals (CI) based on random-effects and fixed-effect models meta-analyses. RESULTS: We identified 20 randomized trials (211,818 participants) assessing beta-carotene, vitamin A, vitamin C, vitamin E, and selenium. The trial quality was generally high. The antioxidant supplements were without a significant effect on the occurrence of gastrointestinal cancers (RR 0.94, 95% CI 0.83-1.06, I(2) = 54.0%). The heterogeneity seemed to be explained by bias risk (low-bias risk trials RR 1.04, 95% CI 0.96-1.13 compared to high-bias risk trials RR 0.59, 95% CI 0.43-0.80, test of interaction P < 0.0005) and type of antioxidant supplement (beta-carotene potentially increasing and selenium potentially decreasing cancer risk). Antioxidant supplements had no significant effect on mortality in a random-effects model meta-analysis (RR 1.02, 95% CI 0.97-1.07, I(2) = 53.5%) but significantly increased mortality in a fixed-effect model meta-analysis (RR 1.04, 95% CI 1.02-1.07). CONCLUSIONS: We could not find evidence that the studied antioxidant supplements prevented gastrointestinal cancers. On the contrary, they seem to increase overall mortality.

Glucocorticoids and oxidative stress.

Glucocorticoids (GC) are used widely for the treatment of patients with various disorders, including autoimmune diseases, allergies, and lymphoproliferative disorders. Glucocorticoid therapy is often limited by several adverse reactions associated with GC excess. Excess GC can elicit a variety of symptoms and signs, including growth retardation in children; immunosuppression; cardiovascular disorders like hypertension and atherosclerosis; osteoporosis; myopathy; and diabetes mellitus. Currently, attention is focused on oxidative stress as one of the major determinants of endothelial dysfunction and cardiovascular senescence. The main reason for all unwanted effects of GC is that dexamethasone induces the overproduction of reactive oxygen species, causing dysregulation of physiological processes. Humans and animals with GC-induced hypertension exhibit reduced nitric oxide levels; patients with excess GC levels also suffer from depression as a consequence of low levels of serotonin and melatonin. The common cofactor for the production of these vasoactive molecules is tetrahydrobiopterin (BH4), which is required for nitric oxide synthesis.

The role of L-arginine in toxic liver failure: interrelation of arginase, polyamine catabolic enzymes and nitric oxide synthase.

The existing interrelation in metabolic pathways of L-arginine to polyamines, nitric oxide (NO) and urea synthesis could be affected in sepsis, inflammation, intoxication and other conditions. The role of polyamines and NO in the toxic effect of mercury chloride on rat liver function was studied. Administration of mercury chloride for 24 h led to significantly elevated plasma activities of Alanine transaminase (ALT) and Aspartate transaminase (AST). Malondyaldehyde (MDA) levels were unaffected (p > 0.05) and arginase activity was significantly decreased (p < 0.05) while nitrate/nitrite production was significantly elevated (p < 0.001) in liver tissue. Polyamine oxidase (PAO) and diamine oxidase (DAO) activities, enzymes involved in catabolism of polyamines, were decreased. L-arginine supplementation to intoxicated rats potentiated the effect of mercury chloride on NO production and it was ineffective on arginase activity. Results obtained in this study show that mercury chloride-induced toxicity leads to abnormally high levels of ALT and AST that may indicate liver damage with the involvement of polyamine catabolic enzymes and NO.

Selenomethionine induces polyamine biosynthesis in regenerating rat liver tissue.

Our study was undertaken to elucidate the effects of selenomethionine (SeMet) on polyamine metabolism in regenerating rat liver tissue, as useful model of rapidly growing normal tissue. We have examined the levels of spermine, spermidine and putrescine in liver tissue. At the same time we have evaluated the activities of polyamine oxidase (PAO) and diamine oxidase (DAO), the catabolic enzymes of polyamine metabolism. The obtained results suggest that polyamine levels in regenerating liver tissue, at 7(th) day after two-thirds partial hepatectomy, were higher in comparison with control group. The administration of selenomethionine to hepatectomized animals during seven days, in a single daily dose of 2.5 microg/100 g body weight, increases the amount of spermine and spermidine; the level of putrescine does not change under the influence of SeMet in regenerating rat liver tissue.PAO activity is lower in regenerating hepatic tissue than in control group. Supplementation of hepatectomized animals with SeMet significantly decreases the activity of this enzyme. DAO activity was significantly higher in hepatectomized and in operated animals treated with SeMet compared to the sham-operated and control ones. The differential sensitivity observed in our model of highly proliferating normal tissue to SeMet, compared with the reported anticancer activity of this molecule is discussed.

Meta-analysis: antioxidant supplements for primary and secondary prevention of colorectal adenoma.

BACKGROUND: Colorectal cancer may be prevented by reducing the development of adenomatous polyps. AIM: To assess the benefits and harms of antioxidant supplements in preventing colorectal adenoma. METHODS: Using the Cochrane Collaboration methodology we reviewed all randomized clinical trials comparing antioxidant supplements with placebo or no intervention. We searched electronic databases and the reference lists until October 2005. Outcome measures were development of colorectal adenoma adverse events. We analysed dichotomous outcomes with fixed- and random-effects model meta-analyses and calculated the relative risk with 95% confidence interval. RESULTS: We identified eight randomized trials (17 620 participants). Neither fixed-effect (relative risk: 0.93, 95% CI: 0.81-1.1) nor random-effect model meta-analyses (0.82, 0.60-1.1) showed statistically significant effects of supplementation with beta-carotene, vitamins A, C, E and selenium alone or in combination. Antioxidant supplements seemed to increase the development of colorectal adenoma in three low-bias risk trials (1.2, 0.99-1.4) and significantly decrease its development in five high-bias risk trials (0.59, 0.47-0.74). The estimates difference is significant (P < 0.0001). There was no significant difference between the intervention groups regarding adverse events, including mortality (0.82, 0.47-1.4). CONCLUSION: We found no convincing evidence that antioxidant supplements have significant beneficial effect on primary or secondary prevention of colorectal adenoma.

Effects of glucocorticoids on polyamine metabolism in liver and spleen of guinea pig during sensitization.

Glucocorticoids are potent anti-inflammatory and immunosuppressive agents. As endogenous inhibitors of cytokine synthesis, glucocorticoids suppress immune activation and uncontrolled overproduction of cytokines, preventing tissue injury. Also, polyamine spermine is endogenous inhibitor of cytokine production (inhibiting IL-1, IL-6 and TNF synthesis). The idea of our work was to examine dexamethasone effects on the metabolism of polyamines, spermine, spermidine and putrescine and polyamine oxidase activity in liver and spleen during sensitization of guinea pigs. Sensitization was done by application of bovine serum albumin with addition of complete Freund's adjuvant. Our results indicate that polyamine amounts and polyamine oxidase activity increase during immunogenesis in liver and spleen. Dexamethasone application to sensitized and unsensitized guinea pigs causes depletion of polyamines in liver and spleen. Dexamethasone decreases polyamine oxidase activity in liver and spleen of sensitized guinea pigs, increasing at the same time PAO activity in tissues of unsensitized animals.

Antioxidant supplements for preventing gastrointestinal cancers.

BACKGROUND: Oxidative stress may cause gastrointestinal cancers. The evidence on whether antioxidant supplements are effective in preventing gastrointestinal cancers is contradictory. OBJECTIVES: To assess the beneficial and harmful effects of antioxidant supplements in preventing gastrointestinal cancers. SEARCH STRATEGY: We identified trials through the trials registers of the four Cochrane Review Groups on gastrointestinal diseases, The Cochrane Central Register of Controlled Trials on The Cochrane Library (Issue 1, 2003), MEDLINE, EMBASE, LILACS, and SCI-EXPANDED from inception to February 2003, and The Chinese Biomedical Database (March 2003). We scanned reference lists and contacted pharmaceutical companies. SELECTION CRITERIA: Randomised trials comparing antioxidant supplements to placebo/no intervention examining the incidence of gastrointestinal cancers. DATA COLLECTION AND ANALYSIS: Two reviewers independently selected trials for inclusion and extracted data. The outcome measures were incidence of gastrointestinal cancers, overall mortality, and adverse events. Outcomes were reported as relative risks (RR) with 95% confidence interval (CI) based on fixed and random effects meta-analyses. MAIN RESULTS: We identified 14 randomised trials (170,525 participants), assessing beta-carotene (9 trials), vitamin A (4 trials), vitamin C (4 trials), vitamin E (5 trials), and selenium (6 trials). Trial quality was generally high. Heterogeneity was low to moderate. Neither the fixed effect (RR 0.96, 95% CI 0.88 to 1.04) nor random effects meta-analyses (RR 0.90, 95% CI 0.77 to 1.05) showed significant effects of supplementation with antioxidants on the incidences of gastrointestinal cancers. Among the seven high-quality trials reporting on mortality (131,727 participants), the fixed effect (RR 1.06, 95% CI 1.02 to 1.10) unlike the random effects meta-analysis (RR 1.06, 95% CI 0.98 to 1.15) showed that antioxidant supplements significantly increased mortality. Two low-quality trials (32,302 participants) found no significant effect of antioxidant supplementation on mortality. The difference between the mortality estimates in high- and low-quality trials was significant by test of interaction (z = 2.10, P = 0.04). Beta-carotene and vitamin A (RR 1.29, 95% CI 1.14 to 1.45) and beta-carotene and vitamin E (RR 1.10, 95% CI 1.01 to 1.20) significantly increased mortality, while beta-carotene alone only tended to do so (RR 1.05, 95% CI 0.99 to 1.11). Increased yellowing of the skin and belching were non-serious adverse effects of beta-carotene. In four trials (three with unclear/inadequate methodology), selenium showed significant beneficial effect on gastrointestinal cancer incidences. REVIEWERS' CONCLUSIONS: We could not find evidence that antioxidant supplements prevent gastrointestinal cancers. On the contrary, they seem to increase overall mortality. The potential cancer preventive effect of selenium should be studied in adequately conducted randomised trials.

Morphometric and biochemical characteristics of short-term effects of ethanol on rat cardiac muscle.

Alcoholism is a very important cause of congestive cardiomyopathy in man. The aim of this study was to examine a short-term effect of ethanol in rat cardiac muscle, using histologic, morphometric and biochemical methods. Experiments were carried out in Wistar male albino rats, divided into two groups: the control group consisting of eight animals receiving tap water, and the experimental group comprising eight animals received ethyl alcohol for ten days, in a single daily dose of 3 g ethanol/kg body weight, per os, using esophageal intubation. The mean volume weighted nuclear volume of cardiac myocytes was estimated by point sampled intercept method, by objective x 100. The mean cubed nuclear intercept length was multiplied by pi and divided by 3. For biochemical analysis, a 10% water tissue homogenate from the left ventricle was made. In the experimental group, the mean volume-weighted nuclear volume (15.08 +/- 5.20 microm3) was significantly lower than in the control group (51.32 +/- 7.83 microm3) (p < 0.001). The treatment of experimental animals with ethanol caused significant increase of aldolase (p < 0.0001) and aspartate transaminase (p < 0.05) activity in the rat cardiac tissue; at the same time, the enzyme activity of creatine phosphokinase, alanine transaminase and alkaline phosphatase were not changed in the experimental group compared to the control values. The amount of the glucose in the cardiac muscle was greater in the experimental group compared to the control animals. Our results suggest that there is depression of cardiomyocyte nuclei in experimental animals treated with ethanol. Alcohol intake results in the loss of Krebs cycle enzymes and as a consequence there is greater utilization of fatty acids for energy production.

[Arginase activity in plasma and erythrocytes in children with hematologic diseases]. / Aktivnost arginaze u plazmi i eritrocitima kod dece s hematoloskim oboljenjem.

INTRODUCTION: Arginase (EC 3.5.3.1) is one of the essential enzymes in the terminal stages of the urea cycle in the liver which participates in the elimination of ammonia from the human body [1, 7]. Except in liver tissue arginase is also present in many human tissues and in the circulating blood cells, especially in erythrocytes and leukocytes. Arginase splits arginase to urea and ornithine that serve for biosynthesis of amino acid proline, glutamic acid and biosynthesis of polyamines-spermine, spermidine and putrescine. Arginase activity is high during the mitotic cycle, with the function in phase S of the cell cycle. The aim of our study was to assess the arginase activity in the blood of children with some haematologic diseases. METHODS: We examined the arginase activity in blood plasma and erythrocytes of children who suffer from some haematological disorders (27 patients) and in healthy children (control group-15 subjects). The enzyme activity was measured with spectrophotometric method on the basis of the determination of the amount of liberated ornithine from substrate-arginine [3]. RESULTS: The obtained results suggest that arginase activity was much higher in the blood of ill children (Table 1 and Figure 1). In the control group of children (total 15) plasma arginase activity was in the range of 0 to 20 U/L x = 0.86 U/L), and enzyme activity in erythrocytes was 1.62-3.98 U/g Hb (x = 2.81 U/g Hb). Erythrocytes enzyme activity and plasma enzyme activity were in ranges of 4.03-5.26 U/L with the mean value of x = 4.56 U/L, and arginase activity in erythrocytes was in ranges of 9.38-14.16 U/g Hb, with mean value x = 11.34 U/g Hb, respectively. Arginase activity in erythrocytes was also significantly higher in children with non-spherocytic haemolytic anaemia (9 children) and was in ranges of 5.33-9.58 U/g Hb (x = 7.29 U/g Hb), with the relatively low values in plasma, 0-4.14 U/L (x = 1.75 U/L). In children with sideropenic anaemia (total number-11) arginase activity in erythrocytes was also very significantly increased with the range between 2.86 and 14.16 U/g Hb (x = 5.54 U/g Hb) while the plasma enzyme activity was relatively low, with the values in range of 0-4.98 U/L (x = 1.41 U/L); in myelodysplastic syndrome (4 pts) arginase activity in plasma was very low (0-0.71 U/L; x = 0.26 U/L) with higher values of arginase activity in erythrocytes (4.22-5.89 U/g Hb; x = 4.94 U/g Hb). DISCUSSION: We have concluded that the enzyme activity was the highest in erythrocyte haemolysates of patients with spherocytosis, non-sherocytic haemolytic anaemia; it was also high, but in a smaller degree, in erythrocytes of children with sideropenic anaemia and myelodysplastic syndrome; arginase activity in plasma of these children was higher in comparison with enzyme activity in plasma and erythrocytes of healthy children. Our results are in agreement with data from literature where it is stated that the younger erythrocytes have the highest arginase activity than the mature erythrocytes [4]. CONCLUSION: The measurement of arginase activity in plasma and erythrocytes is a good diagnostic indicator for the presence of young erythrocytes and reticulocytes in the circulating blood as is the good sign for the detection of haemolytic processes.

Effects of growth factors on the enzymes of purine metabolism in culture of regenerating rat liver cells.

Hepatocytes are affected by many cytokines and growth factors during liver regeneration. In regenerating rat liver cells cultures, liver cell growth factor (LCGF), hepatic stimulator substance (HSS), interleukin-1 beta (IL-1 beta), as well as their combination, were tested for their ability to activate the enzymes involved in purine metabolism. The enzymes tested were 5' nucleotidase, AMP deaminase, adenosine deaminase and xanthine oxidase. The cytokines alone or in combination, activated 5' nucleotidase and adenosine deaminase. Activity of AMP deaminase was stimulated by IL-1 beta associated with LCGF, HSS and IL-1 beta. Xanthine oxidase was stimulated by IL-1 beta but not with HSS and LCGF. Associated with IL-1 beta these two substances decreased its activity. A novel approach to the understanding of the mechanisms involved in the regulation of purine metabolism during liver regeneration, is proposed.

Blood coagulation factors changes during liver regeneration in rats.

Effects of partial hepatectomy on blood coagulation factors were investigated in rats. Analysis were performed 24, 48 and 72 hours after surgery. Howell's time was significantly higher after 24 and 48 h compared to the control value. Prothrombin time was significantly prolonged after 24 h. Partial thromboplastin time did not differ significantly in any time. FII values were significantly reduced after 24 and 48 h, but FV values only after 24 h. FVII showed significant decrease after 24 h, but significant increase at 48 h. FVIII and ATIII average values were significantly lower after 24, 48 and 72 h. Plasma fibrinogen increased. Significant differences were observed 48 and 72 h after surgery. Differences in normalization time of these coagulation factors are most probably the consequence of their synthesis in various cell types, regenerated at different periods after partial hepatectomy.