Checklist of aquatic Diptera (Insecta) of Plitvice Lakes National Park, Croatia, a UNESCO world heritage site.

Studies on aquatic Diptera in the Plitvice Lakes National Park (Croatia) conducted in the last 50 years have produced 157 species and 7 taxa of aquatic Diptera placed in 13 families. Samples were collected at 25 sampling sites representing the four main types of karst aquatic habitats: spring, stream, tufa barriers and lakes. All records of all the aquatic families of Diptera in Plitvice Lakes NP are summarized, including previously unpublished data.

Description of larva and puparium of Oplodontha rubrithorax (Diptera: Stratiomyidae) from the Oriental Region.

This is the first description of larva and puparium of Oplodontha rubrithorax (Macquart, 1838) from the Oriental Region. Larvae were found at a hot spring in North Thailand. The morphological features and cuticular structures of the larva are documented by drawings and SEM micrographs and the main characters are compared with the European O.

Primary rat hepatocytes in chemical testing and QSAR predictive applicability.

Primary rat hepatocytes were used to test acute toxicities of 16 neutral aliphatic alcohols, ketones and esters. Their effects on cell viability and metabolic function (ureogenesis, i.e.

Color discrimination impairment in workers exposed to mercury vapor.

Objective: To study color discrimination impairment in workers exposed to elemental mercury (Hg) vapor.

Subjects: Twenty-four male workers from a chloralkali plant exposed to Hg vapor, aged 42+/-9.8 years, duration of exposure 14.

EEG photic driving in workers exposed to mercury vapors.

Objective: To assess the potential of EEG photic driving (PD) as an indicator of an early neurotoxic effect of long-term, low-level exposure to mercury vapors.

Subjects And Methods: Twenty-four chloralkali workers exposed to mercury vapors; twenty-four age- and gender-matched control subjects. Level of exposure was determined by urinary mercury excreted both spontaneously and after administration of a chelating agent, sodium 2,3-dimercapto-1-propane sulfonate.

Mobilization of mercury by DMPS in occupationally exposed workers and in model experiments on rats: evaluation of body burden.

The aim of the study was to evaluate the efficacy of DMPS (sodium-2,3-dimercapto-1-propane sulfonate) (Dimaval) administration for mobilizing mercury from the body in occupationally exposed people and experimental animals. Two doses of DMPS were administered at a 24-h interval to: (a) groups of people occupationally exposed to merkury--workers of the chloralkali industry (n = 43), and dentists (n = 12), (b) non-exposed individuals (n = 20), and (c) rats chronically exposed to mercury vapour at the concentration of 0.8 mg/m3 Hg degree (6 h/day, 5 days/week) for 15 weeks.

Neurological and electrophysiological examinations on three groups of workers with different levels of exposure to mercury vapors.

The authors performed neurological, visual evoked potentials (VEP) and electroneurography (ENG) examinations on three groups of workers with occupational exposure to mercury vapors (Hg(0)), and on a control group. The exposure of dental professionals (n = 36) was mild, that of chloralkali plant workers (n = 36) was intermediate, and that of workers from mercury works (n = 77) was very high. Symptoms and signs of micromercurialism were observed only in the group with the highest exposure to Hg(0).

Biliary iron excretion in rats following treatment with analogs of pyridoxal isonicotinoyl hydrazone.

Iron overload is a major life-threatening complication of thalassemia major and other iron-loading anemias treated by regular blood transfusions. Although the clinical manifestations of iron overload may be prevented by desferrioxamine, the only iron-chelating drug in routine clinical use, this treatment requires subcutaneous infusion of desferrioxamine for 12 hours each day. New orally effective iron chelators are urgently needed, and pyridoxal isonicotinoyl hydrazone (PIH), which was first recognized as an effective iron chelator in vitro and subsequently in vivo, shows promise for the treatment of iron overload.

Biological monitoring of child lead exposure in the Czech Republic.

The area around the Pribram lead smelter has been recognized to be heavily contaminated by lead (Pb). In the early 1970s, several episodes of livestock lead intoxication were reported in this area; thereafter, several epidemiological and ecological studies focused on exposure of children. In contrast to earlier studies, the recent investigation (1992-1994) revealed significantly lower exposure to lead.

In vivo and in vitro efficacy of a new carbodithioate for the mobilization of cadmium.

Female Wistar rats with chronic cadmium intoxication (oral exposure to low dosages of CdCl2 in drinking water over a period of 90 d) were used to examine the in vivo ability of a newly developed chelator, sodium N-(4-methylbenzyl)-4-O-(beta-D-galactopyranosyl)-D-glucamine-N- carbodithioate (MeBLDTC), singly and in combination with sodium 4-carboxy-amidopiperidine-N-carbodithioate (INADTC) as agents to induce the biliary and urinary excretion of cadmium. The combined administration of the two dithiocarbamates, which differ greatly in molecular weight and structural features, led to a synergistic increase in the biliary excretion of cadmium and an enhanced reduction of renal cadmium levels. The use of such a coadministration produced an increase in the biliary excretion of cadmium that was more than double that expected if the compounds acted in an additive fashion.

Distribution and excretion of cadmium and nickel after simultaneous exposure and the effect of N-benzyl-D-glucamine dithiocarbamate on their biliary and urinary excretion.

A rat model for combined exposure to cadmium and nickel is presented that involves the administration of drinking water containing these elements over a period of 90 d. Coadministration of these two ions in drinking water leads to brain levels of both elements that are significantly higher than results from the administration of equal doses of the metals individually. The enhanced biliary excretion of cadmium in rats given sodium N-benzyl-D-glucamine dithiocarbamate (BGDTC) is almost twice as great in those animals given cadmium and nickel as in those animals given cadmium only.

[Xenobiotic and biochemical parameters of isolated rat hepatocytes].

The authors investigated the effects of the inductors (griseofulvin and fenitoin) and the inhibitors of the cytochrome P-450 (metronidazole, chloramphenicol and phenylbutazone), the effects of the drugs with the purine structure (aminophylline, xanthinol-nicotinate, pentoxiphylline, azathioprine, thioguanine, 6-mercaptopurine), and the effects of several pesticides (lindane, binapicrile, parathion) on some biochemical parameters of the rat liver. The following parameters were determined: viability of hepatocytes, the content of glutathione and cytochrome P-450, and the activity of xanthinoxidase and lipoperoxidase. The experiments were performed in vivo and in vitro.

Mobilization of aged cadmium from isolated rat hepatocytes by sulfhydryl chelators.

Isolated hepatocytes appear to be a suitable in vitro model for the testing of the efficacy of chelating agents. In this study hepatocytes were isolated from rats exposed to CdCl2 (50 mg Cd2+/l) in drinking water for 3 months. The cells were incubated in a Krebs-Henseleit buffer for 2 hrs and the cytotoxicity was assessed using 5 types of parameters.

The study of exposure to cadmium in the general population. I. Autopsy studies.

From 1982 to 1986 samples of materials (liver tissue, kidney cortex) were collected from 438 autopsies in Prague. The age of persons was over 50 years and residence time in the area was at least 10 years Concentrations of Cd and Zn were determined in the kidney cortex and the liver tissue using the AAS method. On the basis of the Questionnaire for Relatives, data on smoking habits, and occupational history of the investigated persons were obtained.

[Pesticides and liver biochemistry].

The effects of various pesticides (lindane, binapacrile and parathion) on the content of cytochrome P450 and glutathione, and on the activity of lipoperoxidase, xanthine oxidase and transaminases (SGOT and SPGT) were examined. Other parameters, such as the relative liver mass and hepatocyte viability were also estimated. All the studied parameters in the liver homogenate and in hepatocytes were changed by binapacrile, whereas in blood only the glutathione level was altered.

Consequences of acrylonitrile metabolism in rat hepatocytes: effects on lipid peroxidation and viability of the cells.

Acrylonitrile caused thiobarbituric acid-positive reactants time- and concentration-dependently in isolated hepatocytes. This effect was markedly enhanced by gassing of the medium with 95% oxygen-5% CO2 gas mixture. Glycidonitrile, an acrylonitrile metabolite, proved more potent in this respect than the parent acrylonitrile or its end metabolite, cyanide anion.

Acrylonitrile potentiation of oxygen toxicity in rats.

Single intraperitoneal injection of acrylonitrile, administered prior to the start, at the onset, or during oxygen exposure, respectively, in all cases significantly impaired the survival rate of rats exposed to 98% oxygen. Short periods of lung glutathione depletion by acrylonitrile accelerated the manifestation of O2 toxicity regardless of their timing with respect to the start of oxygen exposure, but in dependence on their intensity and duration. However, the effect of acrylonitrile was probably not solely glutathione-depletion-mediated, since O2 toxicity was enhanced even by acrylonitrile injection, given sufficiently in advance to allow the lung glutathione level to recover before the oxygen exposure started.

Acrylonitrile inhalation in rats: II. Excretion of thioethers and thiocyanate in urine.

In male Wistar rats, the inhalation exposure to acrylonitrile (AN), 271 mg X m-3, 8 hours a day, 5 days a week, did not affect protein sulfhydryl concentration in liver and blood and decreased glutathione concentration in the liver, but not in the brain at the end of the fifth exposure. The urinary excretion of the main AN metabolites, thioethers (AN-mercapturic acids) and thiocyanate was proportional to the inhaled AN concentration (57, 125, 271 mg X m-3, respectively) in a single exposure for 12 hours, and their mutual ratio was greatly different from that after injection of AN. The results revealed that the urinary excretion of thioethers is a very sensitive and dose-related indicator of exposure to AN and extrapolation of the results indicates that the exposure to AN concentration below 10 mg X m-3 could thus be demonstrated.

Acrylonitrile inhalation in rats: I. Effect on intermediary metabolism.

In male Wistar rats the inhalation exposure to acrylonitrile (AN), 280 mg X m-3, 8 hours a day for five days significantly decreased the serum concentration of cholesterol and triglycerides, but the liver concentrations of phospholipids, and esterified fatty acids were unchanged. The liver microsomal protein and cytochrome P-450 content decreased significantly. On the other hand the levels of glucose, lactate and pyruvate in the blood and brain significantly increased up to 250% of controls.

Two routes of acrylonitrile metabolism.

Acrylonitrile (AN) is metabolized in two different routes. The minor route of AN metabolism is its conversion to cyanide. In vitro experiments confirmed that this biotransformation proceeds via glycidonitrile (catalyzed by hepatic monooxygenases) and glycolaldehyde cyanohydrin (catalyzed by epoxide hydrase).

Acrylonitrile metabolism in the rat.

Acrylonitrile (AN) is metabolized by an oxidative pathway via glycidonitrile and glycolaldehyde cyanohydrin to cyanide (CN-), which is transformed to thiocyanate. The major route of AN metabolism (more than 2/3), however, proceeds via cyanoethylation of glutathione, to N-acetyl-S-(2-cyanoethyl)cysteine (AN-mercapturic acid) as a final product.

Acrylonitrile biotransformation in rats, mice, and chinese hamsters as influenced by the route of administration and by phenobarbital, SKF 525-A, cysteine, dimercaprol, or thiosulfate.

Female wistar rats, conventional albino mice, and Chinese hamsters were given a single dose of acrylonitrile, 0.5 or 0.75 mM/kg body weight.