Idraparinux and liver enzymes: observations from the PERSIST trial

A potential influence of idraparinux--a synthetic analogue of the pentasaccharide sequence in heparins--on plasma liver enzyme levels was analysed in 37 patients suffering from deep vein thrombosis and participating in the PERSIST trial. Plasma gamma-glutamyl-transferase, aspartate aminotransferase and alanine aminotransferase were determined prior to enoxaparin treatment (screening), prior to randomization (baseline) and once weekly during the 12-week treatment period. Patients were initially treated with weight-adjusted enoxaparin for 4-7 days and then randomized to either idraparinux (2.5, 5, 7.5 or 10 mg) or warfarin. Gamma-glutamyl-transferase was significantly increased after administration of enoxaparin at the baseline visit (P = 0.004) and in week 2 (P = 0.009) to return to screening levels in week 3 for the remaining study period (all P > 0.05). Aspartate aminotransferase (P = 0.001) and alanine aminotransferase (P < 0.001) were significantly increased at the baseline visit and returned to screening values at week 2 for the remaining study period (all P > 0.05). There was no significant difference between the mean values of plasma liver enzymes of the four idraparinux groups and the warfarin group in all 13 measurements. We concluded that idraparinux in contrast to enoxaparin does not increase plasma liver enzymes significantly.

[Evaluation of gamma-glutamyltransferase activity and reduced glutathione concentration in liver of rats with acute chlorfenvinphos poisoning ]

The aim of this paper was estimation the GGT activity and GSH concentration in the liver of rats intoxicated with chlorfenvinphos. The experiment was conducted on male Wistar rats divided into three groups: control--which received oil and examined--receiving oil solution of chlorfenvinphos in dose of 0.5 LD50 and 0.1 LD50. At the 1st, 24th and 48th hour after intoxication an activity of enzyme was determined. The GGT activity increased after 48th hour of intoxication with the lower dose of insecticide and after 1st, 24th and 48th with higher dose. The GSH concentration increased at the 1st, 24th and 48th hour of intoxication with chlorfenvinphos at dose 0.1 LD50 and at the 24th hour of intoxication with chlorfenvinphos at dose 0.5 LD50. We suppose that increase in the liver GGT activity can result from disturbance in hepatic function. This increase can influence on the reduced glutathione level.

Effect of mercuric chloride on membrane-bound enzymes in rat testis

AIM

To study the effect of mercuric chloride on the membrane-bound enzymes.

METHODS

The effect of mercuric chloride at two different doses, 1 mg/kg (low dose) and 2 mg/kg (high dose), orally for 30 days, was observed on the membrane-bound enzymes in the testis of adult albino rats.

RESULTS

Mercuric chloride significantly decreased the body weight and testis weight in the high dose group (P< 0.05), but not in the low dose group. The activities of 5'nucleotidase and adenosine triphosphatases were markedly decreased (P< 0.01) in the testis of both groups. Alkaline phosphatase and ggr-glutamyl transferase activities were significantly increased (P< 0.01) in both groups. However, the effect was more pronounced in the high than in the low dose groups.

CONCLUSION

The dose dependent effect of mercuric chloride on these enzymes may affect the membrane characteristics and thereby the fertility of the animal.

Tolterodine-associated acute mixed liver injury

OBJECTIVE

To report a patient with an acute mixed liver injury associated with tolterodine therapy.

CASE SUMMARY

An 81-year-old white woman with urge incontinence experienced malaise, fever, and gastrointestinal disturbances 18 days after starting tolterodine 2 mg twice daily. The patient's concurrent medications included flunitrazepam, diclofenac, and dorzolamide/timolol eye drops. Laboratory examination was consistent with the presentation of an acute mixed liver injury with increased transaminase enzymes, alkaline phosphatase, gamma-glutamyltransferase, and bilirubin. Additionally, she had mild leukocytosis with eosinophilia. After tolterodine was discontinued, the abnormal liver and hematologic parameters returned to normal within 4 weeks.

DISCUSSION

Tolterodine, a muscarinic receptor antagonist, has predominantly anticholinergic effects. To our knowledge, this is the first case published describing tolterodine-associated acute mixed liver injury. However, some of the patient's additional symptoms can also be considered part of a drug-induced hypersensitivity syndrome. This is usually defined by the triad of fever, cutaneous reaction, and involvement of internal organs, mainly affecting the liver. The close temporal relationship between the start of tolterodine therapy and the first symptoms and the reversibility after dechallenge led us to conclude that the adverse reaction was possibly related to tolterodine exposure.

CONCLUSIONS

Our case illustrates that tolterodine may rarely be associated with liver injury. This may have been an organ manifestation of tolterodine-induced hypersensitivity syndrome.

Effects of epomediol on ethinyloestradiol-induced changes in glutathione homeostasis in the rat

Epomediol is a synthetic terpenoid compound that has been reported to reduce ethinyloestradiol-induced cholestasis. The choleretic action of epomediol is related to an increase in both the bile acid-dependent and independent fractions of bile flow, but the role of glutathione metabolism and transport is still unknown. This study was aimed to evaluate if changes in glutathione homeostasis could contribute to the beneficial effects of epomediol in rats with ethinyloestradiol-induced cholestasis. When compared to control animals, ethinyloestradiol treatment resulted in a significant decrease in the liver concentration of reduced (GSH) and oxidized glutathione. Both GSH and oxidized glutathione concentrations returned to normal in animals receiving ethinyloestradiol plus epomediol. Ethinyloestradiol administration induced a significant decrease in plasma and renal GSH and the tripeptide was almost absent from bile. Combined treatment with epomediol plus ethinyloestradiol normalised renal GSH and both biliary and liver cysteine were significantly increased. Liver and kidney gamma-glutamyltranspeptidase activities were higher in rats receiving ethinyloestradiol and still remained elevated in animals with the combined treatment. Liver gamma-glutamylcysteine synthetase activity rose significantly by administration of ethinyloestradiol plus epomediol but the corresponding mRNA levels were not modified. Changes in glutathione homeostasis and higher biliary levels of GSH amino acid constituents could contribute to the beneficial effects of epomediol in rats with ethinyloestradiol-induced cholestasis.

Acute and chronic toxicity of Nigella sativa fixed oil

We investigated the toxicity of the fixed oil of Nigella sativa L seeds in mice and rats through determination of LD50 values and examination of possible biochemical, hematological and histopathological changes. The acute toxicity of Nigella sativa fixed oil was investigated in mice. LD50 values, obtained by single doses, orally and intraperitoneally administered in mice, were 28.8 ml/kg body wt. p.o. [26.2-31.6] and 2.06 ml/kg body wt. i.p. [1.86-2.26], respectively. Chronic toxicity was studied in rats treated daily with an oral dose of 2 ml/kg body wt. for 12 weeks. Changes in key hepatic enzymes levels, including aspartate-aminotransferase, alanine-aminotranferase, and gamma-glutamyltransferase and histopathological modifications (heart, liver, kidneys and pancreas) were not observed in rats treated with Nigella sativa after 12 weeks of treatment. The serum cholesterol, triglyceride and glucose levels and the count of leukocytes and platelets decreased significantly, compared to control values, while hematocrit and hemoglobin levels increased significantly. A slowing of body weight gain was also observed in Nigella sativa treated rats, as compared to control animals. The low toxicity of Nigella sativa fixed oil, evidenced by high LD50 values, key hepatic enzyme stability and organ integrity, suggests a wide margin of safety for therapeutic doses of Nigella sativa fixed oil, but the changes in hemoglobin metabolism and the fall in leukocyte and platelet count must be taken into consideration.

Attenuation of oxalate-induced nephrotoxicity by eicosapentaenoate-lipoate (EPA-LA) derivative in experimental rat model

Hyperoxaluria is one of the major risk factors for the formation of urinary calcium oxalate stones. Calcium oxalate crystals and their deposition have been implicated in inducing renal tubular damage. Lipoic acid (LA) and eicosapentaenoic acid (EPA) have been shown to ameliorate the changes associated with hyperoxaluria. This prompted us to investigate the nephroprotectant role of EPA-LA, a new derivative, in vivo in hyperoxaluric rats. Elevation in the levels of calcium, oxalate and phosphorus, the stone-forming constituents, were observed in calculogenic rats as a manifestation of crystal deposition. Tubular damage to the renal tissue was assessed byassaying the excretion of marker enzymes in the urine. Damage to the tubules was indicated by increased excretion of alkaline phosphatase (ALP), lactate dehydrogenase (LDH), gamma-glutamyl transferase (gamma-GT), beta-Glucuronidase (beta-GLU) and N-Acetyl beta-D glucosaminidase (NAG). Fibrinolytic activity was found to be reduced. Administration of EPA, LA and EPA-LA reduced the tubular damage and decreased the markers of crystal deposition markedly, which was substantiated by the reduction in weight of bladder stone formed. Our results highlight that EPA-LA is the most effective drug in inhibiting stone formation and mitigating renal damage caused by oxalate toxicity, thus confirming it as a nephroprotectant. Further work in this direction is warranted to establish the therapeutic effectiveness of this new derivative.

Kupffer cells inhibition prevents hepatic lipid peroxidation and damage induced by carbon tetrachloride

The aim of this work was to determine if the action mechanism of gadolinium on CCl(4)-induced liver damage is by preventing lipid peroxidation (that may be induced by Kupffer cells) and its effects on liver carbohydrate metabolism. Four groups of rats were treated with CCl(4), CCl(4)+GdCl(3), GdCl(3), and vehicles. CCl(4) was given orally (0.4 g 100 g(-1) body wt.) and GdCl(3) (0.20 g 100 g(-1) body wt.) was administered i.p. All the animals were killed 24 h after treatment with CCl(4) or vehicle. Glycogen and lipid peroxidation were measured in liver. Alkaline phosphatase, gamma-glutamyl transpeptidase, alanine amino transferase activities and bilirubins were measured in rat serum. A liver histological analysis was performed. CCl(4) induced significant elevations on enzyme activities and bilirubins; GdCl(3) completely prevented this effect. Liver lipid peroxidation increased 2.5-fold by CCl(4) treatment; this effect was also prevented by GdCl(3). Glycogen stores were depleted by acute intoxication with CCl(4). However, GdCl(3) did not prevent this effect. The present study shows that Kupffer cells may be responsible for liver damage induced by carbon tetrachloride and that lipid peroxidation is produced or stimulated by Kupffer cells, since their inhibition with GdCl(3) prevented both lipid peroxidation and CCl(4)-induced liver injury.

Relevance of liver enzyme elevations with four different neuroleptics: a retrospective review of 7,263 treatment courses

Data on liver enzyme elevations were collected in a retrospective study of 7,263 treatment courses with haloperidol, clozapine, perphenazine, and perazine. Charts of 233 patients hospitalized between 1980 and 1992 at Tübingen University Psychiatric Clinic were selected because clinically relevant increases of liver enzymes had been detected during monotherapy with one of the four examined neuroleptics. At least one hepatic enzyme (mostly alanine aminotransferase [ALAT]) exceeded the established reference range of 3-fold elevations of ALAT, aspartate aminotransferase, gamma-glutamyl transpeptidase, and glutamate dehydrogenase and 2-fold elevations of alkaline phosphatase (AP) during monotherapy with clozapine in 15%, perazine in 7.6%, perphenazine in 4%, and haloperidol in 2.4% of the cases. If all liver enzyme abnormalities with any elevation greater than the conventional upper limits are considered, incidences were as follows: clozapine, 78%; perphenazine, 62%; perazine, 59%; and haloperidol, 50%. Testing for overall differences within the four neuroleptics resulted in significantly different incidences of liver enzyme elevations (chi2 test,p < 0.0001). Threefold increases of AP (>540 U/L) were seen in three patients receiving haloperidol (0.3%) only. Twofold increases of AP (>360 U/L) were distributed as follows: clozapine, 1%; haloperidol, 0.8%; perazine, 0.3%; and perphenazine, 0.1%. Only in the group with 1-fold elevations of AP (>180 U/L) were the differences within the drug regimens significant (clozapine, 40.3%; haloperidol, 33.2%; perphenazine, 23.4%; and perazine, 23.1%; chi2 test, p < 0.0001). In the period under study, no instance of icterus occurred.

Methylmercury inhibits the in vitro uptake of the glutathione precursor, cystine, in astrocytes, but not in neurons

Maintenance of adequate intracellular glutathione (GSH) levels is vital for intracellular defense against oxidative damage. The toxic effects of methylmercury (MeHg) are attributable, at least in part, to elevated levels of reactive oxygen species, and thus decreases in GSH synthesis may increase methylmercury toxicity. Astrocytes have recently been proposed to play an essential role in providing GSH precursors to neurons. Therefore, cystine transport, a prerequisite to GSH production, was characterized in cultured astrocytes and neurons, and the effects of methylmercury on this transport were assessed. Astrocytes and neurons both possessed temperature dependent transport systems for cystine. Astrocytes accumulated cystine by Na+-independent (X(C)-) and -dependent (X(AG)-) systems while neurons used exclusively Na+-independent systems. Inhibition of the X(AG)- transport system decreased cystine transport in astrocytes to levels equivalent to those in sodium-depleted conditions, suggesting that cystine is carried by a glutamate/aspartate transporter in astrocytes. Inhibition of the multifunction ectoenzyme/amino acid transporter gamma-glutamyltranspeptidase (GGT) decreased cystine transport in both neurons and astrocytes. Inhibition of System X(C)- with quisqualate also decreased cystine uptake in both astrocytes and neurons. These data demonstrate that cultured astrocytes accumulate cystine via three independent mechanisms, System X(AG)-, System X(C)-, and GGT, while cultured hippocampal neurons use System X(C)- and GGT exclusively. Inhibition of cystine uptake in astrocytes by methylmercury appears to be due to actions on the System X(AG)- transporter.

The role of nitric oxide in bradycardia of rats with obstructive cholestasis

Nitric oxide (NO) has an important role in controlling heart rate and contributes to the cholinergic antagonism of the positive chronotropic response to adrenergic stimulation. Based on evidence of NO overproduction in cholestasis and also on the existence of bradycardia in cholestatic subjects, this study aimed to evaluate the chronotropic effect of epinephrine in isolated atria of cholestatic rats and determine whether alterations in epinephrine-induced chronotropic responses of cholestatic rats are corrected after systemic inhibition of NO synthase (NOS) with N(G)-nitro-L-arginine (L-NNA). Male Sprague-Dawley rats were used. Cholestasis was induced by surgical ligation of the bile duct under general anesthesia and sham-operated animals were considered as control. The animals were divided into three groups, which received either L-arginine (200 mg/kg/day), L-NNA (10 mg/kg/day) or saline. One week after the operation, a lead II ECG was recorded from the animals, then spontaneously beating atria were isolated and chronotropic responses to epinephrine were evaluated in a standard oxygenated organ bath. The results showed that plasma gamma-glutamyl transpeptidase and alanine aminotransferase activity was increased by bile-duct ligation, and that L-aginine treatment partially, but significantly, prevented the elevation of these markers of liver damage. The results showed that heart rate of cholestatic animals was significantly less than that of sham-operated control rats in vivo and this bradycardia was corrected with daily administration of L-NNA. The basal spontaneous beating rate of atria in cholestatic animals was not significantly different from that of sham-operated rats in vitro. Meanwhile, cholestasis induced a significant decrease in chronotropic effect of epinephrine. These effects were corrected by daily administration of L-NNA. Surprisingly L-arginine was as effective as L-NNA and increased the chronotropic effect of epinephrine in cholestatic rats but not in sham-operated animals. Systemic NOS inhibition corrected the decreased chronotropic response to adrenergic stimulation in cholestatic rats, and suggests an important role for NO in the pathophysiology of heart rate complications in cholestatic subjects. The opposite effect of chronic L-arginine administration in cholestasis and in control rats could be explained theoretically by an amelioration of cholestasis-induced liver damage by chronic L-arginine administration in bile duct-ligated rats.

Oxidative stress, metabolism of ethanol and alcohol-related diseases

Alcohol-induced oxidative stress is linked to the metabolism of ethanol. Three metabolic pathways of ethanol have been described in the human body so far. They involve the following enzymes: alcohol dehydrogenase, microsomal ethanol oxidation system (MEOS) and catalase. Each of these pathways could produce free radicals which affect the antioxidant system. Ethanol per se, hyperlactacidemia and elevated NADH increase xanthine oxidase activity, which results in the production of superoxide. Lipid peroxidation and superoxide production correlate with the amount of cytochrome P450 2E1. MEOS aggravates the oxidative stress directly as well as indirectly by impairing the defense systems. Hydroxyethyl radicals are probably involved in the alkylation of hepatic proteins. Nitric oxide (NO) is one of the key factors contributing to the vessel wall homeostasis, an important mediator of the vascular tone and neuronal transduction, and has cytotoxic effects. Stable metabolites--nitrites and nitrates--were increased in alcoholics (34.3 +/- 2.6 vs. 22.7 +/- 1.2 micromol/l, p < 0.001). High NO concentration could be discussed for its excitotoxicity and may be linked to cytotoxicity in neurons, glia and myelin. Formation of NO has been linked to an increased preference for and tolerance to alcohol in recent studies. Increased NO biosynthesis also via inducible NO synthase (NOS, chronic stimulation) may contribute to platelet and endothelial dysfunctions. Comparison of chronically ethanol-fed rats and controls demonstrates that exposure to ethanol causes a decrease in NADPH diaphorase activity (neuronal NOS) in neurons and fibers of the cerebellar cortex and superior colliculus (stratum griseum superficiale and intermedium) in rats. These changes in the highly organized structure contribute to the motor disturbances, which are associated with alcohol abuse. Antiphospholipid antibodies (APA) in alcoholic patients seem to reflect membrane lesions, impairment of immunological reactivity, liver disease progression, and they correlate significantly with the disease severity. The low-density lipoprotein (LDL) oxidation is supposed to be one of the most important pathogenic mechanisms of atherogenesis, and antibodies against oxidized LDL (oxLDL) are some kind of epiphenomenon of this process. We studied IgG oxLDL and four APA (anticardiolipin, antiphosphatidylserine, antiphosphatidylethanolamine and antiphosphatidylcholine antibodies). The IgG oxLDL (406.4 +/- 52.5 vs. 499.9 +/- 52.5 mU/ml) was not affected in alcoholic patients, but oxLDL was higher (71.6 +/- 4.1 vs. 44.2 +/- 2.7 micromol/l, p < 0.001). The prevalence of studied APA in alcoholics with mildly affected liver function was higher than in controls, but not significantly. On the contrary, changes of autoantibodies to IgG oxLDL revealed a wide range of IgG oxLDL titers in a healthy population. These parameters do not appear to be very promising for the evaluation of the risk of atherosclerosis. Free radicals increase the oxidative modification of LDL. This is one of the most important mechanisms, which increases cardiovascular risk in chronic alcoholic patients. Important enzymatic antioxidant systems - superoxide dismutase and glutathione peroxidase - are decreased in alcoholics. We did not find any changes of serum retinol and tocopherol concentrations in alcoholics, and blood and plasma selenium and copper levels were unchanged as well. Only the zinc concentration was decreased in plasma. It could be related to the impairment of the immune system in alcoholics. Measurement of these parameters in blood compartments does not seem to indicate a possible organ, e.g. liver deficiency.

Anti-tumor promoting activity of Asteracantha longifolia against experimental hepatocarcinogenesis in rats

Vegetables, natural products of plant origin and numerous non-nutritive dietary constituents have been shown to play a salutary role in cancer chemoprevention. The present study aims to evaluate the chemopreventive efficacy of the methanol fraction of Asteracantha longifolia seed extract against development of 2-acetylaminofluorene (2-AAF)-selected gamma-glutamyl transpeptidase (gamma-GT)-positive foci following diethylnitrosamine (DEN) initiation. Treatment of rats with doses 200 and 400 mg/kg body weight of methanol extract of A. longifolia seeds on alternate days, subsequent to carcinogen treatment, for 6 weeks significantly reduced the incidence and size distribution of gamma-GT-positive foci and tumor formation. Administration of A. longifolia seeds significantly (P<0.001) ameliorated the activities of antioxidant enzymes, glutathione peroxidase (GPx) and catalase (CAT), in a dose-dependent manner. Prophylactic administration of seed extract simultaneous to 2-AAF in the diet, at same doses, significantly suppressed 2-AAF and partial hepatectomy (PH)-induced ornithine decarboxylase (ODC) activity and [(3)H]thymidine incorporation into hepatic DNA, in a dose-dependent manner. Assimilation of the quantitative foci data together with the findings of the modulation of tumor promoting markers give ample evidence to the anti-tumor promoting potential of A. longifolia seeds against chemically-induced hepatocarcinogenesis in Wistar rats.

Fetoprotectivity of the flavanolignan compound siliphos against ethanol-induced toxicity

Of the three flavanolignans that are found in silymarin (Silybum marianum [L.] Gaertn.), silybin is thought to be the primary therapeutic constituent. To test the capacity of silybin to protect the rat fetus from toxic effects of maternally ingested EtOH we did the following: Adult female rats were assigned to one of four groups; EtOH, EtOH/silybin, pair-fed control, and chow fed control. Silybin was orally administered as Siliphos(R), which is one part silybin to two parts phosphatidylcholine. All groups except the chow-fed control were maintained on a liquid diet throughout pregnancy. On day 21 of pregnancy the rats were killed and the fetuses removed. Gamma glutamyl transpeptidase (GGTP) activity and glutathione (GSH) levels were determined for liver and brain tissue for both the fetuses and the dams. Maternal and fetal GGTP activity in the EtOH rats was significantly higher than that of pair-fed controls, whereas the GGTP activity observed in the Siliphos(R)/EtOH rats was not elevated. Fetal mortality rates in the EtOH rats significantly exceeded those of all three other groups.

Fumaric acid esters suppress peripheral CD4- and CD8-positive lymphocytes in psoriasis

BACKGROUND

For severe forms of psoriasis vulgaris, the antipsoriatic fumaric acid esters (FAE) therapy has recently gained increasing acceptance and importance. Until today, there is little knowledge about the mode of action of FAE. However, some evidence exists indicating immunosuppressive effects.

OBJECTIVE

The aim of this study was to examine the systemic, particularly the immunological changes in patients suffering from psoriasis treated with FAE over a long period of time, since we expect to see pharmacological effects of FAE at this point.

METHODS

This study is based on continuously recorded clinical data and laboratory parameters of 10 patients, who were treated over a period of 12 months with FAE. A quantitative analysis of lymphocytes and their subtypes was carried out by means of flowcytometric methods.

RESULTS

3 months after starting treatment with FAE, a clinical effect with a remission index > 95% was achieved in all 10 patients examined. This remained constant until the end of this study. Focusing on leukopenia, and particularly on lymphopenia as important parameters, these effects were found in all patients. The lymphocyte subpopulations data demonstrated extensive proportionate reductions. Within the T cell fraction a stronger suppression of CD8+ lymphocytes was observed.

CONCLUSION

Our investigations of systemic effects of fumaric acid esters demonstrate the suppressive character of this medication. Effects of cell count reduction in leukocyte and lymphocyte numbers over the entire period of 12 months could be observed. The lymphocytic cell count number is obviously linked to the clinical effect.

In vitro effects of folic acid on gamma-glutamyltransferase and glutathione reductase activities in malignant lung and thymus tumors

In vitro effects of folic acid (10(-5), 10(-4), and 10(-3)M) on activities of gamma-glutamyltransferase and glutathione reductase, the enzymes involved in glutathione metabolism, were studied in tissue samples obtained after surgical treatment of the lungs and thymus. Folic acid did not change gamma-glutamyltransferase activity in lung cancer tissue, but in thymoma tissue this substance in a concentration of 10(-3)M inhibited it by 16%. Folic acid had no effects on glutathione reductase activity in benign tumors and normal lung and thymus tissues, but increased this activity in thymoma and lung cancer tissues. Activation of glutathione reductase was probably related to binding of folic acid in the allosteric center of the enzyme, which probably induced conformational changes in the catalytic center, acceleration of electron transport from NADPH(2) to oxidized glutathione via flavin adenine nucleotide, and intense production of reduced glutathione.

A useful model to study the effect of high sugar concentrations upon growth and enzymic activities of toad embryos and larvae

The aim of this study was to develop an oviparous model suitable for studying the differential effects and mechanisms by which a high concentration of extracellular glucose and other sugars produce diabetes complications, particularly body growth retardation during development. Hence, we studied the experimental conditions necessary to obtain measurable effects of high sugar concentrations (5-mM glucose, mannitol, fructose and galactose) upon body growth and development of Bufo arenarum embryos and larvae, and upon the activity of aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT), and alkaline phosphatase (APP). Unfed animals kept in glucose showed lower body weight than controls at all stages, a condition only observed at stage 26 for animals kept in galactose and fructose. All animals reached the same stage of development regardless of the solution in which they were kept. Glucose and fructose significantly decreased the activity of all enzymes tested, while galactose only affected GGT activity. The model provides the first experimental evidence for the deleterious effect exerted in vivo by different sugars upon developing embryos and larvaes of Bufo arenarum. The results prove that this model might help to elucidate the effects and the pathogenic mechanisms of hyperglycemia upon growth and development of embryos exposed to environments with high sugar concentrations. It might also become a useful tool for testing the effectiveness of drugs designed to prevent the deleterious effect of such exposure.

Effects of 5-aminoisoquinolinone, a water-soluble, potent inhibitor of the activity of poly (ADP-ribose) polymerase on the organ injury and dysfunction caused by haemorrhagic shock

Poly (ADP-ribose) synthetase (PARP) is a nuclear enzyme activated by strand breaks in DNA, which are caused inter alia by reactive oxygen species (ROS). Here we report on (i) a new synthesis of a water-soluble and potent PARP inhibitor, 5-aminoisoquinolinone (5-AIQ) and (ii) investigate the effects of 5-AIQ on the circulatory failure and the organ injury/dysfunction caused by haemorrhage and resuscitation in the anaesthetized rat. Exposure of human cardiac myoblasts (Girardi cells) to hydrogen peroxide (H(2)O(2), 3 mM for 1 h, n=9) caused a substantial increase in PARP activity. Pre-treatment of these cells with 5-AIQ (1 microM - 1 mM, 10 min prior to H(2)O(2)) caused a concentration-dependent inhibition of PARP activity (IC(50): approximately 0.01 mM, n=6). Haemorrhage and resuscitation resulted (within 4 h after resuscitation) in a delayed fall in blood pressure (circulatory failure) as well as in rises in the serum levels of (i) urea and creatinine (renal dysfunction), (ii) aspartate aminotransferase (AST), alanine aminotransferase (ALT), and gamma-glutamyl-transferase (gamma-GT) (liver injury and dysfunction), (iii) lipase (pancreatic injury) and (iv) creatine kinase (CK) (neuromuscular injury) (n=10). Administration (5 min prior to resuscitation of 5-AIQ) (0.03 mg kg(-1) i.v., n=8, or 0.3 mg kg(-1) i.v., n=10) reduced (in a dose-related fashion) the multiple organ injury and dysfunction, but did not affect the circulatory failure, associated with haemorrhagic shock. Thus, 5-AIQ abolishes the multiple organ injury caused by severe haemorrhage and resuscitation.

Effect of tenoxicam on biochemical serum parameters of rats

Tenoxicam is a nonsteroidal analgesic of the oxicam group, which possesses both antipyretic and anti-inflammatory characteristics. The use of tenoxicam has recently increased and it is reported in the literature that treatments lasting between a few weeks to three months caused increases in serum alanine transferase (ALT), aspartate transferase (AST), gamma glutamyl transferase (GGT) and bilirubin in humans. Toxic dose treatments to rats caused alterations in renal parameters. To verify these observations, various biochemical parameters were examined following administration of nontoxic doses of tenoxicam to rats. Rats were divided into three groups. One group received tenoxicam 0.6 mg/kg/day; the second group received 1.2 mg/kg/day i.p. The control group received normal saline i.p. At the end of 15 days, blood samples from the animals' hearts were taken for routine biochemical tests. No statistically significant changes were observed in serum urea, uric acid, creatinine, electrolytes, ALT, AST, total protein, bilirubin or glucose levels between the treatment groups and control groups. Increases in GGT levels were found to be statistically significant in both of the treatment groups compared with the control group.

Protective effect of oral L-arginine administration on gentamicin-induced renal failure in rats

We investigated the effects of orally supplemented L-arginine, the substrate of nitric oxide (NO) and N(omega)-nitro-L-arginine methyl ester (L-NAME), a nitric oxide-synthase inhibitor in gentamicin-induced renal failure. Rats were given gentamicin (100 mg/kg/day s.c.), gentamicin and L-arginine (2 g/l, drinking water), gentamicin and L-NAME (100 mg/l, drinking water) or gentamicin plus L-arginine and L-NAME. After 8 days, the gentamicin group developed marked renal failure, characterized by a significantly decreased creatinine clearance and increased blood creatinine, fractional excretion of sodium, fractional excretion of lithium, urine gamma glutamyl transferase, systolic blood pressure and daily urine volume when compared to controls. Renal histological analysis confirmed tubular necrosis. L-arginine administration caused normalization of these parameters, whereas L-NAME led to aggravation of the failure. Concomitant administration of L-NAME and L-arginine to gentamicin-treated rats caused no significant changes when compared to the rats receiving gentamicin alone. We conclude that L-arginine supplementation has beneficial effects in gentamicin-induced renal failure in rats and that these effects are reversed by the NO-synthase inhibitor, L-NAME.

Jeune syndrome and liver disease: report of three cases treated with ursodeoxycholic acid

Three children with Jeune syndrome (asphyxiating thoracic dystrophy) had clinical and laboratory evidence of liver disease. In two patients the disease evolved to biliary cirrhosis, whereas in the third it was recognized when extensive fibrosis was developing. In the three patients, treatment with ursodeoxycholic acid appeared to control the progression of the hepatic dysfunction.

Protective effects of vitamin e and probucol against gentamicin-induced nephrotoxicity in rats

Gentamicin (GM) is widely used as a bactericidal agent for the treatment of severe gram negative infections, however, its clinical use is partially limited due to its nephrotoxicity. Recent evidence suggests a role of reactive oxygen metabolites in GM nephrotoxicity. The present study was designed to investigate a possible potential protective role of vitamin E and/or probucol against GM nephrotoxicity. GM was administered to rats in a single dose of (150 mg kg(-1)i.p.), while vitamin E (250 mg kg(-1)i.m.) and/or probucol (60 mg kg(-1)i.m.) were given once daily for 3 consecutive days prior to GM administration. GM-induced nephrotoxicity was evidenced by marked elevations in serum urea and creatinine levels, urinary activity of N-acetyl-beta- d -glucosaminidase (NAG) and gamma-glutamyl-transferase (gamma-GT). Also, GM caused significant increases in kidney content of malondialdehyde (MDA), and significant decreases in kidney content of reduced non-protein sulphydryls (NPSH) and superoxide dismutase (SOD) activity. Vitamin E pretreatment significantly lowered the elevated serum urea and creatinine levels, and urinary activity of NAG and gamma-GT. In addition, vitamin E ameliorated the rise in renal content of MDA and enhanced the renal NPSH content as well as SOD activity. Similarly, probucol significantly inhibited the elevations in urea and creatinine levels and enhanced renal NPSH content and SOD activity. Simultaneous use of vitamin E and probucol was more effective in mitigating disturbances in the assessed parameters. The present work indicates that, due to their antioxidant activity, vitamin E and probucol have potential protective effects against GM nephrotoxicity.

Ratio of serum gamma-GT/ALT rather than ISDR variability is predictive for initial virological response to IFN-alpha in chronic HCV infection

Chronic hepatitis C virus (HCV) infection in humans is treated at present with interferon (IFN)-alpha. Because the proportion of patients responding to therapy with sustained or even just with transient elimination of viral RNA is low, several potential prognostic parameters have been evaluated to predict the outcome of the therapy. The present study aimed to prove the validity of a predictive parameter described previously for initial virological response, namely the ratio of serum gamma-glutamyltransferase/alanine transaminase (gamma-GT/ALT) activity in connection with virus genotypes 1a, 1b, and 3a, prospectively and to compare the predictive value of these combined parameters with amino acid variability within the interferon sensitivity determining region (ISDR). The prospective analysis confirmed previous data on the predictive value of the serum gamma-GT/ALT ratio. Concerning ISDR variability, the majority of ISDR sequences obtained from the mostly nonresponding type 1b-infected individuals (23/28) resembled nonmutant types (27/ 28). Isolates from type 3a-infected patients responding to therapy in the majority of cases (13/ 20) exclusively resembled nonmutant types when compared with databank type 3a sequences, but were mutant when compared with the prototype sequence HCV-J. However, the initial virological responsiveness among both type 1b- and type 3a-infected patients did not correlate to ISDR variability. In contrast, virological responsiveness was closely related to serum gamma-GT/ALT ratio. The data are not necessarily contrary to the concept that the number of amino acid exchanges within the ISDR compared with the prototype HCV-J sequence is related to some extent to IFN-alpha sensitivity. The ratio of serum gamma-GT/ALT in combination with HCV genotype, however, was found to be a more reliable and stringent predictive parameter.

Inhibition of carcinogen-induced activity of gamma-glutamyl transpeptidase by certain dietary constituents in mouse skin

Cancer chemoprevention, a desirable and important facet of biomedical research, provides a practical approach to identify potentially useful inhibitors of cancer development, and offers an opportunity to study the mechanism of carcinogenesis. During the recent past a number of compounds have been tested for their anticarcinogenic potential specially constituents of human diet. The enzyme gamma-glutamyl transpeptidase (GGT), which catalyses the transfer of glutamyl groups of peptides to other peptides and amino acids, has been proposed as a marker of cell proliferation and neoplasia. It also serves as a tool to evaluate the carcinogenic and cocarcinogenic potential of environmental toxicants. In the present investigations, GGT activity induced by carcinogenic polycyclic aromatic hydrocarbons, viz. 7,12-dimethyl-benz(a)anthracene (DMBA) and benzo(a)pyrene (BaP) was significantly inhibited by diallylsulfide (DAS) and indole-3-carbinol (I3C) in mouse skin. DAS and I3C are constituents of garlic. A significant inhibition in GGT levels was also observed in a strong mitogen (12-o-tetradecanoyl phorbol-13-acetate) induced activity by pretreatment of DAS/I3C in mouse skin. Therefore these dietary constituents seem to be strong modifiers of chemically induced carcinogenesis.