Disorders of the dynamics of postnatal development of monoamine oxidase activity in the brain as affected by the antenatal action of alcohol

The activity of different types of monoamine oxidase (MAO)-MAO, type A (substrate serotonin) and two types of mixed MAO forms using tyramine or dopamine as substrates, in different brain regions of the rat offspring exposed prenatally to ethanol was investigated on the 30th and 60th day postnatally. The present study has revealed differences in the development of brain MAO activity during ontogenesis. Disturbances in the activity of all MAO types investigated as well as the distortion of their postnatal development have been observed in the brain of the rat offspring exposed prenatally to ethanol. The possible teratogenic effect of ethanol on the developing fetal brain is discussed.     

Effects of methoxyfenozide-treated surfaces on the attractiveness and responsiveness of adult codling moth (Lepidoptera: Tortricidae)

The attractiveness and responsiveness of adult codling moth, Cydia pomonella (L.), exposed to surfaces treated with the ecdysteroid agonist methoxyfenozide was investigated in wind tunnel and orientation tube assays. When males were exposed to either water- or surfactant-treated surfaces for 48 h, and regardless of what treatment surfaces the females had been exposed to, the mean percent recaptures of such treated males in the wind tunnel assay were sometimes significantly greater than the recaptures of males that had been exposed to methoxyfenozide. Similarly, in the orientation tube assay, males exposed to methoxyfenozide-treated surfaces almost always had significantly lower mean levels of individuals exhibiting sexual excitability and the mean distances traveled upwind, regardless of female exposures. The two assays demonstrated that male codling moths exposed to methoxyfenozide-treated surfaces were not as responsive to calling females (treated and nontreated) as were the nontreated males. Conversely, females exposed to methoxyfenozide-treated surfaces were just as attractive to nontreated males as were nontreated females. It appears that a male's ability to respond to a calling female is more negatively affected by the ecdysone agonist than a female's ability to call and attract males.     

The distribution of radiation-induced breaks in the chromosomes of irradiated subjects

Distribution of radiation-induced breakpoints in chromosomes and its bands in persons recovered from acute radiation sickness and personnel from Chernobyl NPP were investigated using G-banding staining. The frequency of damaged bands and breakpoints in groups exposed to radiation was significantly higher as compared with the control group. It was shown that in exposed to radiation persons damage depends on its length. Most frequently damaged bands in the observed groups were determined. The G-negative bands and telomeres of chromosomes were more sensitive to radiation.     

Relative size of the foot of two species of Littorina on a rocky shore in Wales

Populations of the gastropods Littorina rudis and L. arcana on the rocky shore at Westdale, Pembroke, South Wales, have been investigated. Foot area has been related to shell length. It is shown that there are differences in the areas of the expanded foot of different groups of snails: those from more exposed sites have a relatively larger foot. Littorina arcana achieves the greatest foot area of all, and it extends on to the most exposed rocks investigated, where L. rudis is absent. It is suggested that this may be important in ecological separation of the two species. It is noted that there is still uncertainty over the taxonomic identity of what is referred to here as 'Littorina rudis' , and further work is in progress.     

Comparative Study of Liver Cancer Patients in Arsenic Exposed and Non-exposed Areas of Pakistan

The investigated data shows that arsenic (As) in drinking water is associated with increased mortality from different types of cancers including liver cancer. In this study, blood and scalp hair samples of male liver cancer patients and healthy referents belonging to As exposed areas of Sindh Pakistan were analyzed for As contents. The As levels in drinking water of understudy area showed that sections of this population was exposed to 3-15-folds higher concentrations of As than permissible limit. For comparative purposes, blood and scalp hair samples of matched cancerous patient as referent patients belonging to big city (Hyderabad) who have used municipal treated water with low As levels <10?μg/L were also collected. The results of this study showed that the average As concentration was higher in the blood and scalp hair of exposed and non-exposed referent cancer patients as compared to referents (p?相似文献   

Effect of extremely-low-frequency pulsed magnetic fields on the mitogenic response of peripheral blood mononuclear cells

The effect of extremely-low-frequency pulsed magnetic fields (PMF) on the response of human peripheral blood mononuclear cells to mitogenic stimulation is reported. We investigated 25 healthy control subjects. Mitogen-stimulated mononuclear cells were exposed to PMF for 72 h and an inhibition of 3H-thymidine uptake was observed in all but one subject. The degree of inhibition of 3H-thymidine uptake was as much as 60%. There was no significant difference between the blastogenic responses of mononuclear cells exposed to PMF for 12 h and control cultures. This study establishes an inhibitory effect of PMF on an in vitro measure of immune function.     

Effects of ultraviolet radiation on an intertidal trematode parasite: an assessment of damage and protection

Trematode parasites are integral components of intertidal ecosystems which experience high levels of ultraviolet radiation. Although these parasites mostly live within hosts, their life cycle involves free-living larval transmission stages such as cercariae which are directly exposed to ambient conditions. UV has previously been shown to considerably reduce the survival of cercariae. Here, we investigated potential mechanisms of protection and damage related to UV in the intertidal trematode Maritrema novaezealandensis. Firstly, the presence of sunscreen compounds (i.e. mycosporine-like amino acids) was quantified in the parasite tissue producing cercariae within a snail host, as well as in the free-swimming cercariae themselves. Secondly, levels of oxidative stress in cercariae after exposure to UV were investigated (i.e.protein carbonyls, catalase and superoxide dismutase). Thirdly, the DNA damage (i.e. cyclobutane–pyrimidine dimers) was compared between cercariae exposed and not exposed to UV. Lastly, functional aspects(survival and infectivity) of cercariae were assessed, comparing cercariae under light conditions versus dark after exposure to UV. We confirmed the presence of my cosporine-like amino acids in cercariae-producing tissue from within snail hosts, but were unable to do so in cercariae directly. Results further suggested that exposure to UV induced high levels of oxidative stress in cercariae which was accompanied by a reduction in the levels of protective antioxidant enzymes present. We also identified higher levels of DNA damage in cercariae exposed to UV, compared with those not exposed. Moreover, no clear effect of light condition was found on survival and infectivity of cercariae after exposure to UV. We concluded that cercariae are highly susceptible to UV damage and that they have very little scope for protection against or repair of UV-induced damage.     

The effect of sucrose and trehalose on viability of one- and two-cell rabbit embryos

The effect of sucrose and trehalose on the viability of one- and two-cell rabbit embryos was investigated. A significant decrease in the viability of one- and two-cell embryos exposed for 30 min. at 20 degrees C was observed. At 38 degrees C none of the two-cell embryos in a sucrose solution survived after 30 min exposure, while approximately 50% of the embryos survived in a trehalose solution. The cleveage rate in culture of two-cell embryos exposed both to 2.0 M or 1.45 M trehalose was significantly lower in comparison with the control group. However the survival rate after transfer of two-cell embryos exposed to 1.45 M trehalose solution at 20 degrees C remained the same as that of the control group.     

Chromatophorenanordnungen in emersen Thalli vonFucus vesiculosus unter verschiedenen Lichtbedingungen

The effects of light and darkness on chromatophore arrangements inFucus vesiculosus thalli exposed to air with one side (half dry) or with both sides (dry) were investigated. Low-intensity arrangement, high-intensity arrangement and dark arrangement were induced in submerged thalli. Then the thalli were exposed to air while light conditions were either kept constant or were changed. Independently of the light conditions, in all thalli exposed to air the chromatophores arranged more or less in the inner area of the cells, in epidermal cells as well as in cortical cells. Thus the chromatophore arrangements observed in submerged thalli differ in some respect from those exposed to low-tide conditions. Based on these observations the physiological and ecological role of chromatophore displacements in seaweeds is discussed.     

Carbon disulfide exposure attenuates adrenergic inotropic response in rats

Catecholamine-induced myocardial necrosis is enhanced in carbon disulfide exposed rats. We investigated whether the reported morphological findings after carbon disulfide exposure are accompanied by functional disturbances of the adrenergic inotropic response as well as by biochemical alterations. The cardiac effects of epinephrine and norepinephrine were studied in urethane-anesthetized rats which had been subacutely exposed to carbon disulfide. Compared with not exposed control animals left ventricular inotropic response was diminished and the transient T-wave elevation of the ECG due to ischemic episodes was enhanced in carbon disulfide-exposed rats. Activity of LDH-isozymes in the myocardium was shifted toward LDH-M. Our results support the hypothesis that carbon disulfide causes disturbances of energy supply in the heart.     

Axial ligation and heme environment in cytochrome c-555 from Prosthecochloris aestuarii. Investigation by absorption and solvent perturbation difference spectroscopy.

The near-IR absorption spectrum indicated that methionine is the sixth axial heme iron ligand in Prosthecochloris aestuarii cytochrome c-555. The heme environment has been investigated by the technique of solvent perturbation difference spectroscopy. The heme octapeptide from cytochrome c plus added imidazole was used as a model compound for the fully exposed chromophore. The heme was found to be minimally exposed to solvent. A comparison was made with cytochrome c, as to the possible causes of the difference in redox potentials betweeen these two cytochromes.     

A study on the positive ellipticity in the circular dichroism of ribonuclease A

The small positive elliplicity near 239 nm in the CD spectrum of RNase has been investigated as a function of pH. Theoretical calculations using CD parameters representing buried or exposed tyrosine residues have been carried out. A comparison of the theoretical calculations with experimental data suggests that the changes in the band's intensity, as a function of pH, arise mainly from electronic transitions associated with the tyrosine residues. The buried tyrosine residues are the major contributors to the ellipticity in this region at neutral pH. At higher pH contributions from exposed residurs are also observed.     

Stability of microtubule protein over the pH range: 6.9--9.5.

The pH stability range of a microtubule protein preparation has been investigated between 6.9 and 9.5. Microtubule protein was exposed to various pH values in this range and then returned to pH 6.9. The appearance of microtubules as verified by electron microscopy and sedimentation analysis under polymerizing conditions was taken as an indication of a conformationally stable protein. Between pH 6.9 and pH 8.0 the loss in the ability to form microtubules was found to be reversible, at pH 8.2 it was partially reversible, above pH 8.2 it was irreversible. Tubulin and the microtubule-associated protein fraction were separately exposed to high pH. It was observed that tubulin exposed to high pH can still form microtubules in the presence of untreated microtubule-associated protein. On the other hand, microtubule-associated protein exposed to high pH could not initiate microtubule assembly with untreated tubulin. It was concluded from these observations that the loss in the ability of a microtubule protein preparation to assemble at high pH is due to a change in the microtubule-associated protein fraction and that tubulin is conformationally stable even after exposure to pH 9.5.     

Cytogenetic monitoring of a group of Italian floriculturists: no evidence of DNA damage related to pesticide exposure

The induction of sister chromatid exchanges (SCE), structural chromosome aberrations (CA) or micronuclei (MN) was investigated in peripheral lymphocytes of a group of Italian floriculturists exposed to a mixture of pesticides. No statistically significant difference in the frequencies of cytogenetic damage was detected between exposed and control subjects. Assessment of the effect of confounding factors indicated that smoking affected both SCE and CA frequencies. Multiple regression analysis showed that in heavy smokers (≥ 20 cigarettes/day), SCE and CA levels increased significantly by 17% and 54%, respectively, as compared to non-smokers.     

Enkephalin content in sections of the brain of rats undergoing intrauterine exposures to ethanol

Leu- and met-enkephalin concentration in the brain structures of rat offsprings prenatally exposed to ethanol (4-5 g/kg) was investigated by radioimmunoassay. Regional and sex differences in enkephalin levels of the investigated brain structures have been shown. In experimental animals that had been exposed to ethanol leu- and met-enkephalin concentration in the hemispheric cortex and hippocump was similar to that in the controls, while in the pituitary body it was significantly decreased. The mechanisms of ethanol effect on endogenous opioid system in the developing brain are discussed.     

Effects of extremely low frequency (50 Hz) magnetic field on morphological and biochemical properties of human keratinocytes

We investigated the effects on human keratinocytes (HaCaT) of exposure to a sinusoidal magnetic field of 2 mT (50 Hz). These cells are a good model for studying interaction of nonionising radiation, because they are not shielded from fields in vivo and also because they are resistant to both mechanical and thermal stimuli. We performed scanning microscopy which showed modification in shape and morphology in exposed cells. This modification is related to differential actin distribution as revealed by phalloidin fluorescence analysis. Moreover, the exposed cells show increased clonogenic capacity, as well as increased cellular growth as showed by clonogenicity assays and growth curves. Indirect immunofluorescence analysis using a fluorescent antibody against involucrin and beta4 integrin, which are respectively differentiation and adhesion markers, revealed an increase of involucrin expression and segregation of beta4 integrin in the cell membrane in cells exposed to 50 Hz; a higher percentage of the exposed cells shows a modified pattern of adhesion and differentiation markers. We also present evidence that exposure of HaCaT cells can interfere with protein kinase activity. Our observations confirm the hypothesis that electromagnetic fields at 50 Hz may modify cell membrane morphology and interfere with initiation of the signal cascade pathway and cellular adhesion.     

Adaptations of the antioxidant system in erythrocytes of trained adult rats: impact of intermittent hypobaric-hypoxia at two altitudes

We have investigated the effects of daily exposure to intermittent hypobaric-hypoxia to two simulated altitudes (5700 m and 6300 m) in adult male rats that had been regularly swim trained in normoxia at sea level prior to exposures. Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) along with the oxidative stress (OS) indices, malondialdehyde (MDA) and protein carbonyl content were measured in erythrocytes and their membranes. Hemoglobin increased in the trained animals exposed to 5700 m and in untrained rats exposed to 6300 m. Osmotic fragility in terms of hemolysis increased in altitude exposed animals. SOD increased in those exposed to 6300 m, while CAT increased in trained rats exposed to 5700 m and to 6300 m unlike in untrained rats where CAT increased only at 6300 m. GSH-Px showed varying degrees of elevation in all animals exposed to both altitudes. Erythrocyte membranes showed significant elevations in malondialdehyde (MDA) at 6300 m, while elevated protein carbonyls were noticeable at both altitudes in whole cells and membranes. These results suggest a positively associated elevation in protein oxidation with altitude in trained rats. At 5700 m, animals were less stressed, unlike at 6300 m, as seen from the magnitude of elevations in the OS indices and from the responses of the antioxidant enzymes.     

Effects of environmentally relevant concentrations of nonylphenol on growth and 20-hydroxyecdysone levels in mysid crustacean, Americamysis bahia

We investigated the effects of environmentally relevant concentrations of nonylphenol (NP) on survival, growth, sexual development and molting of the mysid Americamysis bahia (Crustacea: Mysidacea), including assay of 20-hydroxyecdysone (20E) levels. Seven-day-old mysids were exposed to NP concentrations of 0.3, 1, 3, 10 and 30 microg/L for 14 days. Among growth-related traits we assayed, an effect on body length was the most prominent, with the effects observed at concentrations as low as 1 microg/L NP. In addition, the total number of molting exposed to NP for 14 days was significantly decreased in the treatment groups at 10 or 30 microg/L relative to the controls. These results clearly indicate that subchronic exposure to environmentally relevant concentrations of NP affects growth of mysids. Furthermore, we investigated the effect of NP on production of 20E in female mysids during the molting period. Production of 20E in pre-molting mysids exposed to 30 microg/L of NP was lower than those in control groups, and exposure of female mysids to NP disrupted molting cycles. Taken together, the results suggest that environmentally relevant concentrations of NP can disrupt growth of A. bahia via inhibition of 20E levels and an associated delay in molting.     

Occupational exposure of workers to pesticides: Toxicogenetics and susceptibility gene polymorphisms

Farm workers are often exposed to pesticides, which are products belonging to a specific chemical group that affects the health of agricultural workers and is mostly recognized as genotoxic and carcinogenic. The exposure of workers from Piauí, Brazil, to these hazardous chemicals was assessed and cytogenetic alterations were evaluated using the buccal micronucleus assay, hematological and lipid parameters, butyrylcholinesterase (BChE) activity and genetic polymorphisms of enzymes involved in the metabolism of pesticides, such as PON1, as well as of the DNA repair system (OGG1, XRCC1 and XRCC4). Two groups of farm workers exposed to different types of pesticides were evaluated and compared to matched non-exposed control groups. A significant increase was observed in the frequencies of micronuclei, kariorrhexis, karyolysis and binucleated cells in the exposed groups (n = 100) compared to controls (n = 100). No differences were detected regarding the hematological parameters, lipid profile and BChE activity. No significant difference was observed either regarding DNA damage or nuclear fragmentation when specific metabolizing and DNA repair genotypes were investigated in the exposed groups.     

Effects of methoxyfenozide-treated surfaces on the attractiveness and responsiveness of adult leafrollers

Abstract The attractiveness and responsiveness of the adult redbanded leafroller, Argyrotaenia velutinana (Walker), and obliquebanded leafroller, Choristoneura rosaceana (Harris), exposed to surfaces treated with the ecdysteroid agonist methoxyfenozide were investigated in wind tunnel and orientation tube assays. For both species, when males were exposed to water‐treated surfaces for 48 h, and regardless of what treatment surfaces the females had been exposed to, the mean percentage recaptures of such treated males in the wind tunnel assays were always significantly greater than the recaptures of males that had been exposed to methoxyfenozide. However, exposure to surfaces treated with surfactant (Latron B‐1956) also negatively affected the responsiveness (or attractiveness) of both moth species. In the orientation tube assays, males exposed to methoxyfenozide‐treated surfaces always had significantly lower mean levels of individuals exhibiting sexual excitability, and the mean distances traveled upwind, regardless of females’ exposure. In addition, exposure to surfactant‐treated surfaces did not affect mean levels of sexual excitibility and distances traveled upwind. The two bioassays demonstrated that male A. velutinana and C. rosaceana exposed to methoxyfenozide‐treated surfaces were not as responsive to calling females (treated and non‐treated) as were the non‐treated males. Conversely, females exposed to methoxyfenozide‐treated surfaces were just as attractive to non‐treated males as water‐treated females. It appears that a male's ability to respond to a calling female is more negatively affected by the ecdysone agonist than a female's ability to call and attract males.