Jan Stetkiewicz

DNA damage induced by nitrous oxide: study in medical personnel of operating rooms.

Occupational exposure to anaesthetics such as nitrous oxide (N(2)O) and halogenated hydrocarbons has been suggested to increase risk of genetic damage. However, the dose-dependency of genotoxic effects has not been unequivocally established and their relation to occupational exposure limit (OEL) remain obscure. In this study, the genotoxicity associated with occupational exposure to anaesthetics has been investigated in a group of 55 female nurses and 29 male anaesthesiologists active for at least 5 years in a working environment containing variable concentrations of N(2)O and halogenated hydrocarbons. 83 unexposed health care workers (52 female nurses and 31 male doctors) matched for age, gender, smoking habit and employment duration were included in the control group. Genotoxicity has been assessed using comet test. Concentrations of nitrous oxide, sevoflurane and isoflurane monitored by gas chromatography and mass spectrometry made possible to relate the extent of DNA damage to the level of exposure. Our results for the first time document a positive correlation between the DNA damage and the N(2)O levels in the ambient air. By contrast, no correlation has been observed between genotoxic effects and concentrations of sevoflurane and isoflurane. The extent of genetic injury was especially aggravated among nurses and anaesthesiologists exposed to N(2)O in concentrations exceeding OEL (180 mg/m(3)). We conclude that occupational exposure to N(2)O is associated with increased DNA damage and that the level of exposure plays a critical role in this regard.

Structural aspects of experimental carbon disulfide neuropathy: I. Development of neurohistological changes in chronically intoxicated rats

SummaryIn white rats exposed to CS2 vapors (at the average concentration of 1.5 mg per liter of air) over 1 to 15 months, the progressive development of structural lesions was studied in the selected areas of the central and peripheral nervous system. Gradual destruction of myelinated fibers within the white matter of spinal cord and in the peripheral nerves was observed. Morphological alterations of the body of the nerve cells were also encountered, but their pathologic nature and their relation to the exposure were disputable even at the stage of advanced CS2 induced myelo- and neuropathy.

The inflammatory response in lungs of rats exposed on the airborne particles collected during different seasons in four European cities

Epidemiological studies have reported associations of ambient particulate air pollution, especially particulate matter (PM) less than 10 μm with exacerbations of asthma and chronic obstructive pulmonary disease. In an in vivo model, we have tested the toxicity of urban airborne particles collected during spring, summer, and winter seasons in four cities (Amsterdam, Lodz, Oslo, and Rome) spread across Europe. The seasonal differences in inflammatory responses were striking, and almost all the study parameters were affected by PM. Coarse fractions of the urban particle samples were less potent per unit mass than the fine fractions in increasing cytokine [macrophage inflammatory protein (MIP)-2 and tumor necrosis factor (TNF)-α] levels and in reducing Clara-cell secretory protein (CC16) levels. This study shows that PM collected at 4 contrasting sites across Europe and during different seasons have differences in toxic potency. These differences were even more prominent between the fine and coarse fractions of the PM.

ASSESSMENT OF REPRODUCTIVE TOXICITY AND GONADOTOXIC POTENTIAL OF N-METHYL-2-PYRROLIDONE IN MALE RATS

OBJECTIVES N-methyl-2-pyrrolidone (NMP) is a solvent used in petrochemical, electric and electronic industries, and in the production of paint removers, pesticides and veterinary drugs. The substance exhibits slight acute toxicity, and moderate irritant, embryotoxic and teratogenic effects. The aim of the study was to assess NMP reproductive toxicity and gonadotoxicity in male rats. MATERIAL AND METHODS The animals were exposed per os to NMP at daily doses of 0, 100, 300 and 1000 mg/kg. After 10 weeks of exposure, each male was mated with nonexposed female, then all the males were autopsied, and epididymis and testis were fixed for pathomorphological examination. Viability and development of offspring was observed to 28 days postbirth. RESULTS NMP at 1000 mg/kg was found to produce male infertility and extensive damage to the seminiferous epithelium in the seminal tubules of the testis. When administered at 100 mg/kg or 300 mg/kg, it did not significantly affect fertility or spermatogenesis. NMP exposure at 100 mg/kg did not influence either the viability or the development of their offspring in the first month of life, while exposure at 300 mg/kg resulted in a significantly lower viability of the offspring in the first four days of life. CONCLUSION This study has demonstrated that sub-chronic exposure of male rats to NMP at 1000 mg/kg/day produces gonadotoxic effect and brings about infertility. Administration at lower doses of 100 and 300 mg/kg did not impair male fertility, but only the lowest dose of 100 mg/kg was found to have no influence on the prenatal development of the progeny.

Structural alterations and content of nicotinamide-adenine nucleotides in skeletal muscle of rat in chronic experimental carbon disulfide intoxication

SummaryThe histological nature and extent of muscular lesions and the content of nicotinamide-adenine nucleotides in the skeletal muscles of white rats exposed to CS2 at a concentration of 1.5 mg/l for 1 to 14 months were studied.From the 5th month of exposure muscle atrophy of the denervation type was the constant histological finding. Five months later a significant fall in the nucleotide level was noted, parallel to apparent paresis of the hind limbs and gross muscular atrophy. No evidence of any inflammatory reaction or dystrophic myopathy was found. Reduction of the nucleotide content was attributed therefore to secondary alterations in the metabolism of skeletal muscle undergoing atrophy.

Assessment of neurobehavioral and biochemical effects in rats exposed to copper smelter dusts

Female Wistar rats were instilled per os by gavage with different copper dust samples: P-25 obtained by passing the test material through a 25 μmsieve, and P-0.1 containing soluble matter and ultra-fine, non-soluble<100 nm particulate matter (PM) fraction. The control group received sterile saline. The effects were studied at day 1, 7, and 30 post-exposure, focusing on bronchoalveolar lavage fluid (BALF) analysis (including biochemistry, cell morphology, cell viability, and Clara cell 16 protein concentration) and pathomorphology of lung. Results of biochemical tests showed a strong pro-inflammatory effect of both particulate fractions. The morphological studies after exposure to P-25 and P-0.1 fractions showed multi-focal infiltrations in the alveoli. Changes in behavioral (radial maze and passive avoidance tests) have shown that memory in groups exposed to dust was impaired. Our findings indicate that both samples of dust from Copper Smelter cause greater and lesser intensity (P-25 > P-0.1) of the symptoms of acute inflammatory reaction immediately 24 h after instillation to rats. Exposure results in dropping CC16 protein level in serum of rats. After one month, previous acute inflammation was resolved and transformed in persistent low-grade inflammation. The low-grade inflammation resulted in induction of neurobehavioral effects probably by changes in “cholinergic anti-inflammatory pathway” in which acetylcholine modulates neurotransmission.

Fertility and developmental toxicity studies of diethylene glycol monobutyl ether (DGBE) in rats

ObjectivesThe solvent, dimethylene glycol monobutyl ether (DGBE), is a component of latex paints, inks; it is used as a degreasing agent, industrial detergent. The aim of the study was evaluating the effects of DGBE administered by gavage on the estrous cycle and given with drinking water on fertility in rats and early development of their progeny.Materials and MethodsFemale rats were exposed to DGBE by gavage during 8 weeks at 250, 500 or 1000 mg/kg/day. Vaginal smears were collected during the exposure and 4 weeks after its cessation. Fertility studies were performed in male and female animals exposed to in drinking water. Males were exposed for 10 weeks and then mated with females exposed before mating, during pregnancy and lactation. Young animals were observed during 3 weeks after birth.ResultsDGBE does not cause disturbances of the menstrual cycle in females. Parameters used to assess the general toxicity indicate that males receiving DGBE in drinking water are more sensitive to this compound than females: significantly greater, dose-dependent relative spleen weight, significant decrease in hematological parameters from 8% to 15% depending on the dose, were observed. Clinical chemistry parameters (HDL-cholesterol, BUN) and some markers of oxidative stress differ between the exposed groups and the control one, but without adverse health effect. The microscopic examination of internal organs did not reveal morphological changes in male and female rats.ConclusionThe results of our study on the impact of exposure to DGBE on fertility in rats indicate that the substance administered for 9–10 weeks to females and males at a limit dose of 1000 mg/kg did not impair fertility or viability of their offspring during the first three weeks of life.

Anti-tumor potential of nitroxyl derivative Pirolin in the DMBA-induced rat mammary carcinoma model: A comparison with quercetin

BACKGROUND Considering the role of oxidative stress in carcinogenesis, we investigated the effect of synthetic antioxidant Pirolin (3-carbamoyl-2,2,5,5-tetramethylpyrroline-1-oxyl) on breast cancer progression. Since the anticancer drugs may cause cardiotoxicity due to oxidative stress in the heart muscle, we also evaluated Pirolin performance in heart tissue and compared its effect with that of the natural dietary flavonoid quercetin. METHODS Sprague-Dawley rats were administered with 7,12-dimethylbenz(a)anthracene (DMBA) and then treated ip with an antioxidant (each at a dose of 10mg/kg b.w.) for 14 days. The histopathology of tumors, their size and multiplicity were assesed. The effect of antioxidants on heart tissue was evaluated by the oxidative stress markers and poly (ADP-ribose) polymerase 1 (PARP 1) cleavage. RESULTS The median number of tumors and their volume, at the end of the study, were considerably smaller in both antioxidant-treated groups. We found a better antioxidative performance of quercetin in the heart, since a restoration of the GSH pool and decreased amount of hydroperoxides were observed. Antioxidants did not prevent cardiomyocytes from apoptosis. CONCLUSION The attenuation of tumor progression by Pirolin was comparable with the action of quercetin. No negative changes were observed in the heart of animals after Pirolin treatment. Thus, its use in targeting deregulated redox pathways should be further studied.

Comparison of neurobehavioral and biochemical effects in rats exposed to dusts from copper smelter plant at different locations

Mixed exposure to metals (including arsenic and lead) associated with the neurological and respiratory effects constitute one of the major health problems of copper smelting. Chemical composition of the dust, and the expected health effect of inhalation can be very diverse at different parts of the smelter plant. The aims of this study were to compare lung responses and behavioral effects in female Wistar rats after instillation of dust collected from different production processes at the same smelter department. Dusts collected at two different locations of furnace hall were sifted through 25-μm-mesh sieve. Obtained dust fractions, P-25(I) collected near stove, rich in heavy metals and arsenic, and P-25(II) collected near anode residue storage site, rich in aluminium, were instilled to rats. At 1, 7 and 30 days after dusts instillation, lung injury and inflammation were measured by analyzing sings of lung permeability in the bronchoalveolar lavage fluid (BALF), cell differentiation in BALF sediment and lung morphology. The behavioral studies were done 30 days after exposure. Results of biochemical tests showed a strong pro-inflammatory effect of P-25(I) fractions. Mostly characteristic effects after instillation of P-25(I) samples were 10× increased protein leakages in BALF. Both P-25(I) and P-25(II) fractions caused a reduction of Clara-cell 16 protein concentration (CC16) in BALF and activation of serum butyrylcholinesterase (BChE) at all time points. The morphological studies after exposure to P-25(I) fractions showed multi-focal infiltrations in the alveoli. The behavioral results, especially P-25(II) group rats (in open filed, passive avoidance and hot plate tests), indicated adverse effects in the nervous system, which may be related to changes in the dopaminergic and cholinergic pathway. The symptoms were noted in the form of persistent neurobehavioral changes which might be associated with the content of neurotoxic metals. e.g. Al, Mn and/or As. Decrease of CC16 concentration that occurred immediately after instillation of both dust samples, point out impaired anti-inflammatory potential, resulted in early harmful effect not only to the respiratory tract but also to the whole body, including the nervous system.

Toxic effect in the lungs of rats after inhalation exposure to benzalkonium chloride

BackgroundBenzalkonium chloride (BAC) is a quaternary ammonium compound (QAC) toxic to microorganisms. Inhalation is one of the major possible routes of human exposure to BAC.Materials and MethodsExperiments were performed on female Wistar rats. The rats were exposed to aerosol of BAC water solution at the target concentration of 0 (control group) and 35 mg/m3 for 5 days (6 h/day) and, after a 2-week interval, the animals were challenged (day 21) with BAC aerosol at the target concentration of 0 (control group) and 35 mg/m3 for 6 h.ResultsCompared to the controls, the animals exposed to BAC aerosol were characterized by lower food intake and their body weight was significantly smaller. As regards BAC-exposed group, a significant increase was noted in relative lung mass, total protein concentration, and MIP-2 in BALF both directly after the termination of the exposure and 18 h afterwards. Significantly higher IL-6 and IgE concentrations in BALF and a decrease in the CC16 concentration in BALF were found in the exposed group immediately after the exposure. The leukocyte count in BALF was significantly higher in the animals exposed to BAC aerosol compared to the controls. In the lungs of rats exposed to BAC the following effects were observed: minimal perivascular, interstitial edema, focal aggregates of alveolar macrophages, interstitial mononuclear cell infiltrations, thickened alveolar septa and marginal lipoproteinosis.ConclusionInhalation of BAC induced a strong inflammatory response and a damage to the blood-air barrier. Reduced concentrations of CC16, which is an immunosuppressive and anti-inflammatory protein, in combination with increased IgE concentrations in BALF may be indicative of the immuno-inflammatory response in the animals exposed to BAC aerosol by inhalation. Histopathological examinations of tissue samples from the BAC-exposed rats revealed a number of pathological changes found only in the lungs.