Biomedical subjects

Maja Peraica

Publications and source records attributed to Maja Peraica.

14 recordsLinked to original sources

PubMed2006

Standard and Fpg-modified comet assay in kidney cells of ochratoxin A- and fumonisin B(1)-treated rats.

The effect of ochratoxin A (OTA), fumonisin B(1) (FB(1)), and their combinations on DNA damage was studied using the standard alkaline comet assay and the Fpg-modified comet assay. Rats were orally receiving OTA (5 ng/kg b.w., 0.05 mg/kg b.w., and 0.5mg/kg b.w., respectively) for 15 days, FB(1) (200 ng/kg b.w., 0.05 mg/kg b.w., and 0.5mg/kg b.w., respectively) for 5 days, and the combinations of two lower OTA and FB(1) doses. The tail length, tail intensity, and Olive tail moment (OTM) obtained with the standard comet assay and Fpg-modified comet assay were significantly higher in treated animals than in controls, even at the lowest dose of OTA or FB(1) (p<0.01). The Fpg-modified comet assay showed significantly greater tail length, tail intensity, and OTM in all treated animal than did the standard comet assay (p<0.05), which suggests that oxidative stress is likely to be responsible for DNA damage. DNA damage detected by the standard comet assay at all OTA or FB(1) doses indicates that some other mechanism is also involved. Combined OTA+FB(1) treatment measured either by the standard comet or the Fpg-modified comet assay showed a synergistic increase in the tail intensity and OTM in kidney cells, even at doses that correspond to the daily human exposure in Europe.

Animals↗

PubMed2005

Recent data on endemic nephropathy and related urothelial tumors in Croatia.

Endemic nephropathy (EN) is a renal disease of unknown etiology. In Croatia it occurs in the rural population in 14 villages located in the western part of Brodsko-Posavska county. This region also has an unusually high incidence of otherwise rare upper urothelial cancers. Between 1991 and 2002 the average general mortality for both sexes in the endemic region was 10.3 per thousand and the specific mortality for patients with EN was 0.65 per thousand (M 0.58/10((3)), F 0.72/10(3)). The average age of death of patients with EN was 69.2 years (M 67.7, F 70.3), which is similar to the life expectancy for the rest of the population in the county (67.8, M 64.4, F 71.8). This life expectancy is significantly higher than in the period 1957-1960 when the average age of EN-related death was 45.1 years. Between 1995 and 2002, in contrast to both Croatia as a whole and the respective county, the specific mortality with tumors of the pyelon and ureter in the endemic region was much higher in women than in men (9.020 and 4.697 per 100,000, respectively). The specific mortality of all patients with urothelial tumors was 14 times higher in the endemic region than in Brodsko-Posavska county and 55 times higher than in Croatia overall. The much higher specific urothelial-tumor mortality in women than in men (in contrast to the rest of the country) and the higher specific EN mortality indicate that the causative agent of the two nosological entities is the same.

Adult↗

PubMed2005

Fumonisin B1, fumonisin B2, zearalenone and ochratoxin A contamination of maize in Croatia.

Mycotoxins are products of moulds that frequently contaminate maize. In this study the presence of mycotoxins fumonisin B1 (FB1), fumonisin B2 (FB2), zearalenone (ZEA) and ochratoxin A (OTA) was determined in 49 maize grain samples collected in autumn 2002. The most frequent finding was that of FB1(100%), followed by ZEA (84%) and OTA (39%), while FB2 was found only in three samples. The co-occurrence of two and three mycotoxins was found in 55 and 37% of samples, respectively. The concentrations (mean +/- SD) of FB1, ZEA and OTA in positive samples were 459.8 +/- 310.7, 3.84 +/- 6.68 and 1.47 +/- 0.38 microg kg(-1), respectively, and the concentrations of FB2 in three positive samples were 68.4, 109.2 and 3084.0 microg kg(-1). Although such low concentrations of mycotoxins are not a significant source of exposure in countries with a European diet, a few samples with extreme values indicate that thorough control is needed.

Carcinogens↗

PubMed2005

Ochratoxin A in wine.

A high-performance liquid chromatography (HPLC) method for determination of ochratoxin A (OTA) in wine was developed and checked on 14 samples of wine produced in the Republic of Croatia. OTA detection in red and white wine was validated checking the linearity of the method (r2=0.997 and 0.999, respectively), recovery (88 and 95 %, respectively), and precision (RSD=3.1 and 1.4 %, respectively). The detection limit of OTA in both red and white wine was 10 ng L(-1). The OTA concentration in all red wines was above the detection limit (mean 22+/-11 ng L(-1)), while only 4 of 7 white wines contained OTA (mean 10+/-9 ng L(-1)). Three OTA-free white wines were from the north of Croatia (inland), while all wines produced in the south (Adriatic coast) were OTA-positive. However, the concentrations were too low to present a risk for a moderate wine consumer.

Carcinogens↗

PubMed2005

Butyrylcholinesterase activity and plasma lipids in dexamethasone treated rats.

The paper describes the effect of glucocorticoid dexamethasone (DM) given intraperitoneally on the catalytic activity of butyrylcholinesterase (BuChE) measured in plasma, liver and white adipose tissue of rats of both sexes. Effects of DM on the concentration of plasma lipids and lipoproteins were also tested. Rats were given multiple (2 and 4) pharmacological doses (0.4 and 3.0 mg kg(-1) body mass) of DM. All animals were sacrificed 48 hours after the last dose. Administration of DM significantly decreased the catalytic activity of BuChE in plasma and liver of all treated groups regardless of sex. BuChE catalytic activity in white adipose tissue differed depending on the dose and frequency of administration. In contrast to liver where both doses caused significant BuChE inhibition, the lower DM dose did not inhibit BuChE activity in adipose tissue, and the inhibition achieved by the higher dose was not as strong as in liver. This result corroborates an earlier hypothesis that BuChE is also synthesized in the adipose tissue. DM significantly increased plasma concentrations of triglycerides, total cholesterol and high-density lipoprotein (HDL) cholesterol and decreased the low-density lipoprotein (LDL) cholesterol concentration. Neither positive correlation between BuChE and triglycerides nor negative correlation between BuChE and HDL was found. Changes in lipid profile during DM treatment were not sex- and time-dependent.

Adipose Tissue↗

PubMed2005

The effect of ochratoxin A on the concentration of protein carbonyls in rats.

The mechanism of ochratoxin A (OTA) toxicity has been found to involve the production of free radicals and consequent oxidative stress. Until now, the only studied pathway of OTA-caused oxidative damage was peroxidation of lipids. The aim of this study was to check whether OTA induced the production of protein carbonyls, markers of protein oxidation. Exposed rats (5 per group) were given daily OTA (0.5 mg kg(-1) b. w., i. p.) for 7 days, 14 days, or 21 days, and control rats solvent only (TRIS). All animals were killed 24 hours after the last treatment. The levels of OTA in plasma, kidney and liver homogenates increased gradually during the whole length of the experiment. The levels of protein carbonyls in kidney homogenates of OTA-treated rats was significantly higher after days 14 and 21 than in controls (P < 0.05). The levels of protein carbonyls in the liver was significantly higher in OTA-treated animals only after day 21 (P < 0.05). These results confirm that oxidative stress is involved in the mechanism of OTA toxicity, and that it causes the oxidation of proteins.

Animals↗

PubMed2005

Mould contamination and co-occurrence of mycotoxins in maize grain in Croatia.

Maize grain samples (n=15) collected during the autumn of 2002 were analyzed for the presence of moulds and mycotoxins fumonisin B1 (FB1), fumonisin B2 (FB2), zearalenone (ZEA), and ochratoxin A (OTA). Mycological analysis showed that all samples were contaminated with Fusarium spp. and Penicillium spp., while Aspergillus spp. were found in 5 samples. F. proliferatum and F. verticilloides, the producers of fumonisins, were found in 14 and 8 samples, respectively, while F. graminearum, the producer of ZEA, was present in all samples. The most frequent mycotoxins were FB1 (15/15) and ZEA (12/15), followed by OTA (7/15), while FB2 was found in only two samples. Seven samples were contaminated with two mycotoxins, seven with three, and one sample with only one mycotoxin. The concentrations (mean+/-SD) of FB1, ZEA, and OTA in positive samples were 459.5+/-314.6, 1.70+/-0.80, and 1.40+/-0.55 microg kg-1, respectively, and the concentrations of FB2 in two samples were 68.4 and 3084.0 microg kg-1. In general, such low mycotoxin concentrations are not a significant source of exposure to humans, but they may contribute to exposure from other commodities. A few samples with extreme values indicate that strict control is needed.

Aspergillus↗

PubMed2004

Ochratoxin A-induced apoptosis in rat kidney tissue.

The aim of our study was to find whether ochratoxin A (OTA) induces the apoptosis and/or necrosis of kidney tissue in rats. In the first experiment, the highest number of apoptotic cells was found in rats sacrificed one day after OTA administration (1.00 mg/kg b.w., i.p.). The number of apoptotic cells reduced gradually and they were not seen nine days after OTA administration. A possible dose-dependence of histological changes was checked in kidney tissue of rats given 0.25, 0.50 or 1.00 mg of OTA/kg b.w., i.p. three times a week for four weeks. The number of apoptotic cells showed a clear dose-dependence, but necrosis was absent even at the highest doses. The time-dependent appearance of lesions related to OTA administration was checked by administering 0.50 mg OTA/kg body weight to rats, and sacrificing them one day after 1, 3, 6, and 9 doses/administrations, or 6 and 21 day after 12 doses/administrations. Long-term administration is associated with continued and increased apoptosis without necrosis, suggestive of OTA's role in the pathogenesis of progressive renal atrophy.

Animals↗

PubMed2003

Two different clean-up procedures for liquid chromatographic determination of ochratoxin A in urine.

This paper describes two different procedures for extraction of ochratoxin A (OTA) from urine samples: one using acidic chloroform-methanol mixture, followed by solid-phase extraction (SPE) clean-up and the other using commercial Chem Elut columns and a chloroform-formic acid mixture. The recovery of OTA using the procedure with silica gel columns was 82% with a R.S.D. < 8.4% and the detection and quantitation limits were 0.5 and 1.5 ng OTA/ml, respectively. The recovery of OTA in the second procedure with urine samples purified only on commercial Chem Elut columns was 95% with R.S.D. < 4.0%, and detection and quantitation limits 0.3 and 0.9 ng/ml, respectively. Both procedures of OTA extraction effectively eliminate interfering substances and give reliable and repeatable results. However, the procedure with Chem Elut columns gave higher recovery and lower detection and quantitation limits. It was successfully applied in determining OTA in human urine samples.

Chromatography, High Pressure Liquid↗

PubMed2002

Adamantyl tenocyclidines--adjuvant therapy in poisoning with organophosphorus compounds and carbamates.

The objective of this study was to evaluate the efficacy of thienyl phencyclidine (tenocyclidine, TCP) and its newly synthesized adamantyl derivatives containing piperidine (TAPIP), pyrolidine (TAPIR) and morpholine (TAMORF) groups, which were tested with or without standard therapy in mice poisoned with organophosphates (OPs) and carbamates. These compounds with potential activity at the N-methyl- D-aspartate and muscarinic receptors showed low acute toxicity, having LD50 values varying from 106.00 mg/kg (TCP) to >504.00 mg/kg body weight (TAMORF). TCP and its adamantyl derivatives were administered intraperitoneally (2.5 mg/kg body weight) together with atropine (10.0 mg/kg body weight) and with or without 1/4 LD50 of the oxime HI-6. Each compound administered with atropine had a therapeutic effect against poisoning with carbamates propoxur, aldicarb and Ro 02-0683 (protective ratio of tenocyclidines was from 3.99 LD50 of aldicarb to >16.00 LD50 for propoxur). However, the efficacy of those compounds in combination with atropine was lower against poisoning with the OP insecticide dichlorvos (DDVP) and chemical warfare agents soman and tabun. In soman-poisoned mice, the best therapeutic effects were obtained with the combination of HI-6 plus atropine and test compounds, with protective ratios being from 5.40 to 7.12 LD50 of soman. The results suggest that TCP and adamantyl tenocyclidines could be used in combination with atropine as antidotes in carbamate poisoning and as adjuvant therapy to HI-6 and atropine in soman poisoning.

Adamantane↗

PubMed2002

The effect of cycloheximide on butyrylcholinesterase activity in vivo.

The paper describes the catalytic activity of butyrylcholinesterase (BuChE) measured in plasma, liver, white adipose tissue, heart, and brain of rats intraperitoneally administered a single non-lethal dose of cycloheximide (2.0 mg/kg body weight; CHM). The BuChE assay was performed on rats of both sexes either administered CHM or saline (controls), and killed 2, 3, 4, 5, 10 days later. A significant decrease of BuChE catalytic activity was observed in all tested tissues except plasma. In animals of both sexes, the lowest BuChE catalytic activity was found in the liver (2-6%), while it was higher in white adipose tissue, heart, and brain. However, the respective values remained significantly different from controls (33-67%, 49-62%, and 14-71% in males, and 24-82%, 72-86%, and 33-67% in females). Since there was no effect of CHM on BuChE catalytic activity in plasma, the data suggest that CHM inhibits the synthesis of BuChE rather than its active site.

Animals↗

PubMed2002

Prevention of exposure to mycotoxins from food and feed.

Mycotoxins are metabolites of moulds that may be found in food and feed of plant and animal origin. This paper gives a short review of the agronomical methods and food and feed storage recommendations for the prevention of mould contamination. It describes the practical methods of feed decontamination and the use of feed additives where mycotoxin contamination prevention has failed. However, these methods should be avoided as much as possible because they may increase the cost of production, reduce the nutritional value of feed, and leave residues of mycotoxins or their toxic metabolites. Since there is no universal and reliable method of feed decontamination for all mycotoxins, the paper stresses the importance of preventive measures.

Animal Feed↗

PubMed2002

The effect of dichlorvos treatment on butyrylcholinesterase activity and lipid metabolism in rats.

This paper describes the effects of dichlorvos (DDVP) on butyrylcholinesterase (BuChE) activity with possible consequences for lipid and lipoprotein metabolism in rats. The rats of both sexes were given a single and multiple doses of DDVP (8.0 mg/kg body weight) with two-day intervals between administrations, ensuring the continuous inhibition of BuChE activity without lethal outcome. BuChE activity was measured in plasma, liver, and white and brown adipose tissue. The recovery of BuChE activity was observed only in white adipose tissue of female rats 10 days after treatment. Our results show that DDVP significantly decreases BuChE activity in female and male rat plasma (40-60%; P < 0.05), and significantly increases triglycerides (60-600%; P < 0.05) and total cholesterol (35-75%; P < 0.05). In contrast to the increased HDL-cholesterol (20-30%; P < 0.05), LDL-cholesterol decreased (30-40%; P < 0.05). The decrease of BuChE activity and the changes in concentrations of lipids and lipoproteins were observed throughout the experiment. Our results contribute to the hypothesis that BuChE may play a role in lipid and lipoprotein metabolism.

Animals↗

PubMedDate not supplied

Spontaneous mycotoxic nephropathy in Bulgarian chickens with unclarified mycotoxin aetiology.

Histopathological, biochemical and toxicological investigations of tissues and blood of normally slaughtered chickens exhibiting different frequencies (1-2%, 40-50% and above 80%) of nephropathy changes (congested or pale and enlarged kidneys) at the slaughtering meat inspection were carried out to elucidate the aetiology of nephropathies of chickens encountered in Bulgaria. A close relationship was observed between the frequency of this nephropathy and the rate of nephrotoxic mycotoxin ochratoxin A in muscles, kidneys and livers of chickens, but the levels of ochratoxin A in corresponding feed samples (0.1-0.3 ppm) were significantly lower than the levels (2-4 ppm) required to reproduce such nephropathy. Clinicomorphological changes such as nervous symptoms, vascular and oedematous changes in various internal organs and the brain, and subcutaneous or liver and kidney haemorrhages in addition to known degenerative changes in the kidneys, liver and lymphoid organs differed from the classical description of the nephropathy made in Scandinavia. The conclusion is that the Bulgarian chicken nephropathy may have a multitoxic aetiology because it cannot be explained by the concentration of ochratoxin A alone.

Animals↗