The role of home smoking bans in limiting exposure to secondhand tobacco smoke in Hungary.

Our objective was to assess how exposure to secondhand tobacco smoke occurs in Hungarian homes, particularly among non-smokers, and to examine the effectiveness of home smoking bans in eliminating exposure to secondhand smoke at home. In 2009, 2286 non-smokers and smokers aged 16-70 years, who were selected randomly from a nationally representative sample of 48 Hungarian settlements, completed paper-and-pencil self-administered questionnaires addressing tobacco-related attitudes, opinions and behaviors. Chi-square tests, one-way analysis of variance and multivariate logistic regression models were used to assess the effect of demographics, socio-economic characteristics and home smoking policies on the risk of exposure to secondhand tobacco smoke at home. Significantly higher risk of exposure was found among younger, lower educated and poorer people and among those having no or partial home smoking restrictions. There was a significant interaction between education level and home smoking policies: the effect of a smoking ban on exposure to secondhand tobacco smoke was stronger for the lower educated group than the higher educated group. The results suggest that Hungarians are making good progress in implementing home smoking bans, and that in the majority of population these bans are working. More can be done to promote the uptake of home smoking bans among poorer and less educated subpopulations.

Behavioral effects of subchronic inorganic manganese exposure in rats.

BACKGROUND: Manganese, an essential micronutrient, is a potential neurotoxicant in prolonged overexposure. Parkinson-like syndrome, motor deficit, disturbed psychomotor development are typical signs of neuropathological alterations due to Mn in humans. METHODS: Young adult rats, in three groups of 16 each, received 15 and 59 mg/kg b.w. MnCl(2), (control: distilled water) via gavage for 10 weeks, and were kept for further 12 weeks. Correlation of MnCl(2) exposure to body and organ weights, neurobehavioral effects (spatial memory, exploratory activity, psychomotor performance, pre-pulse inhibition), and histopathological changes (gliosis) was sought. RESULTS: By the end of treatment, Mn accumulated in blood, cortex, hippocampus, and parenchymal tissues. Body and organ weights were reduced in high dose rats. All treated rats showed hypoactivity, decreased memory performance, and diminished sensorimotor reaction. In the dentate gyrus of these, GFAP immunoreactivity increased. During the post-treatment period, body weight of the high dose group remained decreased, locomotor activity returned to control, but the lasting effect of MnCl(2) could be revealed by amphetamine. CONCLUSION: Using complex methodology, new data were obtained regarding the relationship between the long-term effects of MnCl(2) at neuronal and behavioral level.

A study on immunotoxicological effects of subacute amitraz exposure in rats.

The effects of amitraz, a formamidine pesticide, were investigated in four-week old outbred male Wistar rats on certain classic toxicological and haematological parameters as well as on specific immune functions. The animals were treated, per os by gavage for 28 days, in a five-day treatment two days break system, with 26.5, 21.1, 10.6 and 5.29 mg/kg/day amitraz. On the 29th day, organ weights of the thymus, heart, lung, spleen, liver, kidneys, adrenals, testicles and popliteal lymph node; WBC and RBC counts, Ht, MCV, haemoglobin; and cell content of the femoral bone marrow were determined. In two separate groups, the effects of amitraz on the PFC content of the spleen, and on the maximum level and time course of DTH reaction, were investigated. Amitraz in 26.5 mg/kg dose increased relative adrenal weight, and decreased relative liver weight, MCV value, PFC content of the spleen, and the maximum level of DTH reaction. The 21.1 mg/kg dose decreased only MCV value, while 10.6 mg/kg elevated the liver-to-brain weight ratio. Based of these findings, a NOEL dose of 5.29 mg/kg was determined for amitraz in this experimental system; while the LOEL doses were 10.6 mg/kg for the general toxicological, 21.1 mg/kg for the haematological and 26.5 mg/kg for the immune function parameters. The results show that the exposure sensitivity of these immune functions to amitraz is lower than that of some other toxicological and haematological parameters.

Immunotoxicological investigation of subacute combined exposure with low doses of Pb, Hg and Cd in rats.

Detectable interactions between NOEL (No Observed Effect Level) doses of Pb, Hg and Cd in general toxicological, hematological, and immune function parameters were investigated. The metals (Pb-acetate, 20 mg/kg; HgCl2, 0.40 mg/kg; CdCl2, 1.61 mg/kg) were combined. First, the rats received the combination Pb + Hg + Cd for 4 weeks per os. Significant difference vs. control was found only in the weight of lung and popliteal lymph node (PLN). The Pb + Hg and Pb + Cd combinations significantly decreased the PLN to 100 g body weight and PLN to brain weight ratio, and Pb+Hg also decreased the relative adrenal weight. After 12 weeks treatment with the same doses, effects on the thymus, kidney, and adrenal weights in the Pb + Hg, and thymus weight in the Pb + Cd, combination were seen. Pb + Cd also affected the white and red blood cell count and hematocrit. Combined with Hg or Cd, NOEL dose Pb showed toxicity, indicating that exposure limits may be inefficient in combined exposure situations.

Stimulus frequency dependence of the central and peripheral somatosensory evoked activity in rats treated with various pesticides.

Rats were treated with a combination of insecticide agents in different timing schemes. In acute administration, 1/5 LD50 of the three insecticides: dimethoate, propoxur and cypermethrin, or their combination, was given once by gavage. In the developmental model, female rats received oral doses of 1/25 LD50 of the above insecticides in combination in three timing schemes including pregnancy and lactation. Responses in the somatosensory cortex and in the tail nerve, evoked by peripheral electric stimulation, were recorded in acute preparation under urethane anesthesia. It was tested whether the parameters of the cortical and peripheral evoked response are dependent on the frequency and whether this dependence is different in control and treated animals. The latency increase of the cortical responses with increasing stimulation frequency was significantly stronger in rats treated acutely with cypermethrin and the combination, and in rats receiving the combination during both intra- and extrauterine development. On the duration, the effects were less clear. Frequency dependent increase of the tail nerve action potential latency was significantly intensified by cypermethrin, and the amplitude decrease, by cypermethrin and dimethoate. Fatigue of this response during a stimulation series was also altered by the insecticides. Frequency dependence and fatigue possibly reflect the actual state of the nervous system and may have the potency to be developed to functional biomarkers.

A study on behavioral, neurotoxicological, and immunotoxicological effects of subchronic arsenic treatment in rats.

Male Wistar rats were treated for 4, 8, and 12 wk with 3.33, 6.66, 13.3, or 26.6 mg/kg of inorganic arsenic (NaAsO(2)) per os by gavage. Changes in behavioral and electrophysiological parameters (spontaneous open-field exploration; electrocorticogram mean frequency and power spectrum; latency and duration of somatosensory, visual, and auditory evoked potentials; conduction velocity; and relative and absolute refractory period of a peripheral nerve) were determined. Treated rats exhibited hypoactivity of horizontal ambulation in the open field and showed depressed rates of grooming. The electrophysiological data, recorded from anesthetized rats, did not show any significant dose- and time-dependent changes. Changes in humoral immune response, tested after 4 wk of treatment, were not marked. The weight of organs responsible for immune response (thymus, spleen, adrenals), was significantly reduced, as were delayed-type hypersensitivity (DTH) reaction and mean cell volume (MCV) of red blood cells a hematological parameter. Plaque-forming cell (PFC) assay proved to be insensitive in this short-time exposure. These results suggest that subchronic low-level exposure to arsenic can affect immune responses and/or spontaneous behavior of rats.

A study on geno- and immunotoxicological effects of subacute propoxur and pirimicarb exposure in rats.

A 28-day oral exposure with 8.51, 3.40, and 0.851 mg/kg propoxur (PR) and 4.67, 1.87, and 0.467 mg/kg pirimicarb (PI) was performed in male Wistar rats, and the occurrence of numerical and structural chromosome aberrations and the changes in certain immune function parameters (plaque-forming cell (PFC) assay, delayed-type hypersensitivity reaction) and in some basic toxicological (body weight gain and weights of brain, thymus, lung, heart, liver, spleen, kidneys, adrenals, and popliteal lymph node) and hematological (white blood cells, red blood cells, hematocrit (Ht), mean cell volume of red blood cells (MCV) cell content of the femoral bone marrow) parameters were investigated. The high dose of PR increased the relative liver weight and the cell content of femoral bone marrow, and all three doses increased Ht and MCV. The applied doses of PI decreased the relative adrenal weight in a dose-dependent manner, and its highest dose increased the relative liver weight. Among the immune function parameters tested, PFC content of the spleen was decreased by high-dose PR and elevated by high-dose PI, whereas the maximum and the time course of the delayed-type hypersensitivity reaction showed no changes in this dose range. In the genotoxicological investigations only the high PR dose increased the number of numerical, but not the structural, chromosome aberrations. In addition to the changes in relative adrenal weight following PI treatment, the PFC assay showed the highest sensitivity for detection of the 4-week exposure with these carbamates. On the basis of our results, the immunotoxicological approach seems to have the same (PR) or higher (PI) sensitivity in early detection of the repeated low-dose exposure by these carbamates compared to the genotoxicological approach.

Small subchronic doses of the pesticide dimethoate and/or cadmium and lead treatment causes disturbances in the chromosomes of young rats.

Small doses of Dimethoate (DM) and cadmium (Cd) which in themselves proved to be harmless in causing chromosome aberrations, potentiate each other's toxic effect concerning both numerical and structural aberrations caused in rat bone marrow cells. The toxic effect of lead (Pb) was not enhanced by DM.

Behavioural effects of subchronic lead treatment in combination with ethanol in rats.

The effect of lead acetate administration during perinatal (1. prenatal, 2. prenatal and suckling period, 3. prenatal + suckling period + 4 weeks after weaning) development in combination with ethanol was investigated in Wistar rats at the age of 12 weeks on open-field behaviour and auditory startle response. Lead intoxication has on the investigated behavioural parameters the most pronouncing effect when applied during the days 5-15 of pregnancy.

Immunotoxicological effects of repeated combined exposure by cypermethrin and the heavy metals lead and cadmium in rats.

The immunotoxic effect of a 28 days oral exposure by 55.4, 22.2, and 11.1 mg/kg cypermethrin (CY) was investigated in 4 weeks old male Wistar rats. The applied test system involved the determination of general toxicological parameters (body weight gain, organ weight of thymus, heart, lung, liver, spleen, kidneys, adrenals and the popliteal lymph node), haematological parameters (white blood cell count, red blood cell count, haematocrit, mean cell volume of red blood cells, cellularity of the femoral bone marrow), as well as immune function assays (splenic plaque forming cell assay, delayed type hypersensitivity reaction). The highest dose resulted in a significant increase of the relative liver weight, and all three doses resulted in (although inconsistent) changes in the haematocrit and MCV values. The maximum of DTH reaction decreased at all three doses. On combination of the highest CY dose with non-effective doses of lead or cadmium the immunotoxic effects of the former were modified. When immunotoxic doses of Cd or Pb were combined with the lowest CY dose, further interactions were observed on the examined parameters. The alterations of the immunotoxic effects of CY by simultaneous exposure with Cd or Pb, as described here, can lead to unexpected health consequences and/or can lead to false positive or negative results in human epidemiological studies.

Electrophysiological biomarkers of an organophosphorous pesticide, dichlorvos.

The correlations between the relatively low level, chronic dichlorvos (DDVP) treatment and the early electrophysiological changes were investigated in three series of experiments. In the first series, male Wistar rats were orally given daily by gavage 0.98, 1.96 and 3.92 mg/kg of DDVP for 4, 8, or 12 weeks, and recordings were made at the end of each period. In the second one, the male and female rats of three consecutive generations were treated with the same doses, the investigated parameters were recorded at the age of 12 weeks of the male animals. In the third experiment, the doses were administered in different stages of development: during pregnancy, pregnancy + lactation, pregnancy + lactation + postweaning, and the electrophysiological markers were recorded also at the age of 12 weeks of male offspring. The analyzed elecrophysiological parameters were: electrocorticogram, sensoric cortical evoked potentials, conduction velocity and refractory periods of peripheral nerve. The data showed that the relatively low level dichlorvos exposure caused dose-, duration-, generation-, developmental stage-dependent and partly significant alterations in all the investigated electrophysiological parameters. The analyzed functional parameters proved to be sensitive biomarkers of the exposure as they were changed by the lower doses, while the brain cholinesterase activity was considerably inhibited only in the groups given the highest dose.

Epidemiological investigations and experimental model studies on exposure of pesticides.

Authors carried on epidemiological examinations on plant protection workers to find early symptoms (biomarkers) of moderate contamination by pesticides. Measurement of changes in cholinesterase and gamma glutamyltransferase enzyme activity did not reveal that people were affected. Determination of chromosome abnormalities from peripheral lymphocytes disclosed numerical aberrations at an early stage and lasted after cessation of work for several months. There were differences in the results among different groups of plant protection workers, as well as among those working in open field or in glasshouses. Women, who carried out horticultural work in glasshouses after spraying showed some chromosome abnormalities too. Experimental rats treated chronically with organophosphates exhibited changes in spontaneous and evoked brain electrical activity (ECoG). Concerning the peripheral nervous activity, conduction velocity became slower, absolute and relative refractory periods became longer. These proved sensitive biomarkers too, which could be used in early detection of contamination.

Experimental model studies of pesticide exposure.

The neurotoxic effects of Dimethoate (Dim), Dichlorvos (DDVP) and Methyl-Parathion (MP) respectively were investigated on the central nervous system (CNS) and peripheral nervous system (PNS) of rats after different treatment schedules at the macro and single unit cell level. At the macro investigations 1/25, 1/50 and 1/100 of the respective LD50 values of each pesticide were administered to different groups by gavage daily in the following programs: Pregnancy variation (P) to females from 5th to 15th days of pregnancy; Pregnancy and lactation variation (P+L): to females as above and during lactation for 4 weeks; Pregnancy+lactation+post weaning variation (P+L+P) as above plus to the young male rats (F1 generation) up to 8 weeks. Neurotoxicological investigations were conducted on the F1 rats at the age of 12 weeks. Spontaneous electrocorticograms (ECoG) were recorded on the anesthetized rats from the somatosensory, visual and auditory cortex. Cortical evoked potentials (EP) were recorded from the same areas subsequently. Conduction velocity and refractory periods of the tail nerve was investigated. Treatment by Dim, DDVP and MP during P and P+L of the mothers did not influence the bioelectric activity of the offsprings significantly. The same treatment by the P+L+P programme, resulted in significant changes. Frequency of the spontaneous ECoG waves grew significantly in all dose groups of P+L+P group. Latency time become shorter after somatosensory. light or acoustic stimuli respectively on one hand and the beginning of the of answer of these by the evoked potential (EP) waves on the other hand. Conduction velocity of the tail nerve diminished, refractory periods grew dose dependently and significantly at the P+L+P programs with all the three pesticides. Cortical single unit activity was studied after the i.p administration of 1/5 LD50 of the three organophosphates (OP). The decrease of the firing frequencies was observed. The amplitude of the hippocampal population spikes increased. The changes observed in these studies point toward a higher excitation state of the CNS and a disturbed conduction of the nervous impulses of the peripheral nerves. These results could be taken into consideration when deciding on human contaminations by OP-s.

Developmental neurotoxicological effects of lead and dimethoate in animal experiments.

Neurophysiological changes caused by parallel treatment with inorganic lead and dimethoate (a combination of possible health risk at population level) were investigated in different phases of the ontogenesis. Wistar rats were treated by gavage with lead (80.0 or 320.0 mg/kg); with dimethoate (7.0 or 28.0 mg/kg), or with their combination on days 5-15 of pregnancy, days 5-15 of pregnancy + days 2-28 of lactation (females of P generation), or days 5-15 of pregnancy + days 2-28 of lactation (females of P generation) + 8 weeks after weaning (males of F1 generation). Electrophysiological parameters (electrocorticogram, cortical evoked potentials) of the F1 male rats in the above groups were investigated at the age of 12 weeks. Both spontaneous and evoked electrophysiological phenomena showed dose-, treatment- and combination-dependent changes (e.g. significantly decreased mean amplitude and increased frequency of the electrocorticogram, lengthened latency and duration of the somatosensory, visual and auditory evoked potentials) which seemed to be more pronounced in the groups treated with the combination of lead and dimethoate than in the groups given lead or dimethoate alone. The results indicate that a simultaneous, pre- and postnatal exposure to the neurotoxicants, lead and dimethoate, considerably altered the functioning of the central nervous system.

Behavioural and neurotoxicological changes caused by cadmium treatment of rats during development.

Behavioural and electrophysiological changes caused by inorganic cadmium were investigated in the offspring of female Wistar rats. Dams were given 3.5, 7.0 or 14.0 mg kg(-1) cadmium (cadmium chloride dissolved in distilled water) in three different treatment regimes: days 5-15 of pregnancy; days 5-15 of pregnancy + 4 weeks of lactation; days 5-15 of pregnancy + 4 weeks of lactation followed by the same oral treatment of male rats of the F1 generation for 8 weeks. The behavioural (open-field exploration) and electrophysiological (electrocorticogram, cortical evoked potentials, conduction velocity and refractory periods of a peripheral nerve) parameters of F1 male rats exposed by various treatments were investigated at the age of 12 weeks. It was found that cadmium dose and treatment time dependently altered the spontaneous and evoked electrophysiological functions (e.g. increased the frequency of the electrocorticogram, lengthened the latency and duration of evoked potentials, etc.). Interestingly, only the combination of treatment during prenatal development and the 4-week suckling period resulted in a significant dose-dependent decrease of horizontal and vertical exploratory activity and a significantly lower exploration frequency of the open-field centre. The results showed that low-level pre- and postnatal inorganic cadmium exposure affects the bioelectrical and higher order functions of the nervous system. In the case of human populations, a similar prolonged exposure might be just as harmful.

Behavioural and functional neurotoxicological changes caused by cadmium in a three-generational study in rats.

1. Three consecutive generations of Wistar rats were orally treated by gavage with 3.5, 7.0 or 14.0 mg/kg cadmium (in form of cadmium chloride diluted in distilled water) over the period of pregnancy, lactation and 8 weeks after weaning. 2. Behavioural (open field behaviour) and electrophysiological (spontaneous and evoked cortical activity, etc.) parameters of male rats from each generation were investigated at the age of 12 weeks. 3. The main behavioural outcomes were change in vertical exploration activity (rearing) and increased exploration of an open field centre. The spontaneous and evoked electrophysiological variables showed dose- and generation-dependent changes (increased frequencies in the electrocorticogram, lengthened latency and duration of evoked potentials, etc.) signalling a change in neural functions. 4. The data show that low-level, multigeneration exposure to inorganic cadmium can affect functions of the nervous system. This suggests that cadmium exposed human populations may be at risk of developing nervous system disorders.

Electrocorticogram changes caused by subchronic lead treatment of rats.

Male Wistar rats were treated per os through gavage for 4, 8 and 12 weeks by 80.0, 160.0 and 320.0 mg/kg lead in form of lead acetate. The changes of certain parameters (mean frequency, mean amplitude, ECoG index-the ratio of the slow and fast bands, power spectrum of the frequency bands) of the electrocorticogram (ECoG) recorded from the primary somatosensory, visual and auditory centres of anaesthetized rats were analysed. The data show that all investigated parameters had dose- and time-dependent changes: increased mean frequencies accompanied by decreased mean amplitudes and ECoG-indices. These changes were significant only at the highest, or at the two higher dose groups by the end of the experiment. The data suggest that subchronic, low-level exposure of lead can affect the integrated electrophysiological function of the brain.

Effect of subchronic mercury exposure on electrocorticogram of rats.

Mercury is a neurotoxic compound causing irreversible disorders of the central and peripheral nervous system. In some of the previous human and experimental studies mercury also affected some functional neurological parameters such as EEG, and cortical evoked potentials. In the present study, the effect of subchronic (4, 8, and 12 weeks) relatively low-level (0.4, 0.8, and 1.6 mg/kg mercury in form of HgCl2, per os by gavage) treatment on the basic cortical activity was investigated. Certain parameters of electrocorticogram (ECoG) recorded simultaneously from the primary somatosensory, visual and auditory centres were analyzed. The results showed that mercury had a dose- and time-dependent effect on the examined ECoG parameters, and the changes became significant by the end of the experiment of week 12.