Effect of somatotropin on survival and diameter of bovine preantral follicles / Efeito da somatotropina na sobrevivência e no diâmetro de folículos pré-antrais de bovinos

The aim of this study was to evaluate the effect of Recombinant bovine somatotropin (rbST) on survival and diameter of bovine preantral ovarian follicles (PAOF) cultured in vitro. Ovaries were collected from adult cows and fragments of ovarian cortex were immediately fixed (non-cultured control) or cultured in vitro in α-MEM+ alone or containing 10, 50, 100 or 1,000ng/mL rbST. The fragments were processed for Classical Histology and Transmission Electron Microscopy. After one and seven days of culture, the percentage of normal follicles in the non-cultured control was superior (P< 0.05) to the follicles cultured in α-MEM+ alone or with different rbST concentrations. The oocyte and follicular mean diameter did not increase during the culture for one and seven days, both in media containing rbST and in the medium without this hormone. The only medium in which there was no reduction in follicular diameter with the time of culture was the medium without rbST. Ultrastructural damage in PAOF cultured in vitro was found. It is concluded that the use of rbST at different concentrations in in situ culture of bovine preantral follicles has no beneficial effects on survival and growth of bovine PAOF.(AU)

O objetivo deste trabalho foi avaliar o efeito da somatotropina recombinante bovina (rbST) sobre a sobrevivência e o diâmetro de folículos ovarianos pré-antrais (FOPA) bovinos cultivados in vitro. Ovários foram coletados de vacas adultas e fragmentos do córtex ovariano foram imediatamente fixados (controle não cultivado) ou cultivados in vitro em α-MEM + sozinho ou contendo 10, 50, 100 ou 1.000ng/mL de rbST. Os fragmentos foram processados para histologia clássica e microscopia eletrônica de transmissão. Após um e sete dias de cultivo, o percentual de folículos normais no controle não cultivado foi superior (P<0,05) aos cultivados em α-MEM + sozinho ou acrescido de diferentes concentrações de rbST. Os diâmetros médios oocitário e folicular não aumentaram durante o cultivo por um e sete dias, tanto nos meios contendo rbST, como no meio sem esse hormônio (α-MEM + ). O único meio em que não houve redução no diâmetro folicular com o tempo de cultivo foi o sem rbST. Verificaram-se ainda danos ultraestruturais em FOPA cultivados in vitro. Conclui-se que o uso de rbST em diferentes concentrações no cultivo in situ de folículos pré-antrais bovinos não tem efeitos benéficos na sobrevivência e no crescimento de FOPA bovinos.(AU)

Biomarker Evaluation in Fish After Prolonged Exposure to Nano-TiO2: Influence of Illumination Conditions and Crystal Phase.

In this study, we evaluated the effects of prolonged exposure to two different nano-TiO2 crystal phases under different illumination conditions. Fish (Piaractus mesopotamicus) were exposed for 21 days to 100 mg/L of nano-TiO2 anatase and a mixture of anatase:rutile (80%:20%) under visible light and UV light (UVA and B, 22.47 J/cm2/h). The following oxidative stress biomarkers were mon- itored: concentrations of lipid hydroperoxide (LPO), carbonylated proteins (PCO), and specific activ- ities of superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST). Other biomarkers as well as specific activities of acid phosphatase (AP), Na+, K(+)-ATPase and metalloth- ionein levels (MT) were also evaluated. Moreover, micronucleus and comet assays were performed to assess genotoxicity. Our results showed low toxicity of nano-TiO2 to fish and lack of titanium accumulation in muscle tissue. However, it was observed the occurrence of sublethal effects that were influenced by nano-TiO2 crystal phase and illumination condition. Pure anatase caused more oxidative damage without co-exposure to UV, while the mixture anatase:rutile caused more sub- lethal effects when exposure occurred under UV. These findings show that the specific activity of CAT, GST, PCO levels and comet assay are useful as biomarkers of prolonged exposure to nano- TiO2. Overall, our study substantiates the development and implementation of nanoecotoxicological protocols.

Toxicity assessment of TiO2 nanoparticles in zebrafish embryos under different exposure conditions.

The popularity of TiO2 nanoparticles (nano-TiO2) lies in their wide range of nanotechnological applications, together with low toxicity. Meanwhile, recent studies have shown that the photocatalytic properties of this material can result in alterations in their behavior in the environment, causing effects that have not yet been fully elucidated. The objective of this study was to evaluate the toxicity of two formulations of nano-TiO2 under different illumination conditions, using an experimental model coherent with the principle of the three Rs of alternative animal experimentation (reduction, refinement, and replacement). Embryos of the fish Danio rerio were exposed for 96h to different concentrations of nano-TiO2 in the form of anatase (TA) or an anatase/rutile mixture (TM), under either visible light or a combination of visible and ultraviolet light (UV). The acute toxicity and sublethal parameters evaluated included survival rates, malformation, hatching, equilibrium, and overall length of the larvae, together with biochemical biomarkers (specific activities of catalase (CAT), glutathione S-transferase (GST), and acid phosphatase (AP)). Both TA and TM caused accelerated hatching of the larvae. Under UV irradiation, there was greater mortality of the larvae of the groups exposed to TM, compared to those exposed to TA. Exposure to TM under UV irradiation altered the equilibrium of the larvae. Alterations in the activities of CAT and GST were indicative of oxidative stress, although no clear dose-response relationship was observed. The effects of nano-TiO2 appeared to depend on both the type of formulation and the illumination condition. The findings contribute to elucidation of the factors involved in the toxicity of these nanoparticles, as well as to the establishment of protocols for risk assessments of nanotechnology.

Fish exposure to nano-TiO2 under different experimental conditions: methodological aspects for nanoecotoxicology investigations.

The ecotoxicology of nano-TiO2 has been extensively studied in recent years; however, few toxicological investigations have considered the photocatalytic properties of the substance, which can increase its toxicity to aquatic biota. The aim of this work was to evaluate the effects on fish exposed to different nano-TiO2 concentrations and illumination conditions. The interaction of these variables was investigated by observing the survival of the organisms, together with biomarkers of biochemical and genetic alterations. Fish (Piaractus mesopotamicus) were exposed for 96 h to 0, 1, 10, and 100 mg/L of nano-TiO2, under visible light, and visible light with ultraviolet (UV) light (22.47 J/cm(2)/h). The following biomarkers of oxidative stress were monitored in the liver: concentrations of lipid hydroperoxide and carbonylated protein, and specific activities of superoxide dismutase, catalase, and glutathione S-transferase. Other biomarkers of physiological function were also studied: the specific activities of acid phosphatase and Na,K-ATPase were analyzed in the liver and brain, respectively, and the concentration of metallothionein was measured in the gills. In addition, micronucleus and comet assays were performed with blood as genotoxic biomarkers. Nano-TiO2 caused no mortality under any of the conditions tested, but induced sublethal effects that were influenced by illumination condition. Under both illumination conditions tested, exposure to 100 mg/L showed an inhibition of acid phosphatase activity. Under visible light, there was an increase in metallothionein level in fish exposed to 1 mg/L of nano-TiO2. Under UV light, protein carbonylation was reduced in groups exposed to 1 and 10 mg/L, while nucleus alterations in erythrocytes were higher in fish exposed to 10 mg/L. As well as improving the understanding of nano-TiO2 toxicity, the findings demonstrated the importance of considering the experimental conditions in nanoecotoxicological tests. This work provides information for the development of protocols to study substances whose toxicity is affected by illumination conditions.

Evaluation of the genotoxicity induced by the fungicide fenarimol in mammalian and plant cells by use of the single-cell gel electrophoresis assay.

Fenarimol, a systemic pyrimidine carbinol fungicide, is considered to be not genotoxic or weakly genotoxic, although the available toxicological data are controversial and incomplete. Our results obtained in vitro with leukocytes of two different rodent species (rat and mouse) show that fenarimol affects DNA, as detected by the single-cell gel electrophoresis (SCGE, Comet) assay. This fungicide is able to induce DNA damage in a dose-related manner, with significant effectiveness at 36 nM, but without significant interspecies differences. Simultaneous exposure of rat leukocytes to fenarimol (36-290 nM) and a model genotoxic compound (50 microg/ml bleomycin) produced a supra-additive cytotoxic and genotoxic effect. This supports previous findings suggesting possible co-toxic, co-mutagenic, cancer-promoting and co-carcinogenic potential of fenarimol, and modification of the effects of other xenobiotics found to be influenced by this agrotoxic chemical, with consequent different toxicological events. The potential for DNA strand breaks to act as a biomarker of genetic toxicity in plants in vivo was also considered, in view of the fact that higher plants represent reliable sensors in an ecosystem. Significant DNA breakage was observed in the nuclei of Impatiens balsamina leaves after in vivo treatment with fenarimol (145 nM, 1h). More than 50% of the cells showed such DNA damage.

Biological monitoring of embrio-fetal exposure to methamidophos or chlorothalonil on rat development.

Maternal exposure to pesticides during the pre-implantation and very early post-implantation periods of pregnancy is correlated with numerous adverse effects on the offspring and in reproductive parameters like an increase in resorption, a decrease in fetal survival and weight, and teratogenic effects. Although the epidemiological evidence is inconclusive as regards the risk of the adverse outcome of pregnancy and developmental toxicity events, the use of biomarkers in exposure assessment may contribute to recognizing a potential health impairment. The present study evaluated the influence of prenatal oral exposure to an insecticide (1.0 mg methamidophos/kg) or a fungicide (200.0 mg chlorothalonil/kg) during gestation days 1 to 6 on maturational and behavioral aspects of offspring development of rats. The pesticides did not affect the body weight gain of dams and offspring, nor did the exposure affect the weight of gravid uterus, fetus, placenta and ovary. There were no observed alterations in the swimming behavior tested at postnatal days 7, 14 and 21, but the pesticides interfered with physical and maturational development landmarks of offspring according to age, showing subtle effects on behavioral and physical development. These findings show the importance of categorizing developmental effects, establishing the relationship between age and important performances, to recognize potential impacts on human populations.

Relevance of developmental testing of exposure to methamidophos during gestation to its toxicology evaluation.

The organophosphate insecticide (OP) are known to be able to promote cholinergic toxicity related to neurobehavioral findings. The measures of cholinesterase activity are the most common index of its action. The influence was evaluated, of the OP methamidophos (1.0 mg/kg), by oral exposure during gestational organogenesis of rats, on maturational and behavioral aspects of offspring development. This dose did not promote evidence of maternal toxicity. The pesticide did not affect body weight gain of the dams and offspring, but interfered with the offspring's physical and maturational development landmarks according to age. The behavioral performance of the offspring with or without a pharmacological challenge was tested at different postnatal days (pnd 14, 21 and 40) in an open-field apparatus. The results showed a large standard deviation that prejudiced the conclusions. There were no observed alterations in the swimming behavior tested also at pnd 7, 14 and 21. As long as the obtained results showed some subtle effects on rat development, the data, as possible additional effect biomarkers for risk analysis, will aid further studies of the embryo-feto-toxic potential of OP exposure.

Twelve years' experience with non-heart-beating cadaveric donors.

From 1983 to August 1995, the University of Miami Organ Procurement Organization evaluated 41 candidates for non-heart-beating cadaveric donation and determined that 34 patients met the criteria. All patients had irreversible brain injury incompatible with survival. All families gave permission for withdrawal of life support and for tissue and organ donation after cardiac arrest. Thirteen donors died in the operating room, and 9 died in the ICU or emergency department. Four of the 9 patients who died in the ICU had undergone femoral cannulation. The remaining 12 donors were brain-dead but had an unpredicted cardiac arrest before laparotomy. All kidneys were preserved by using machine pulsatile perfusion, and 21 kidneys were transported to other centers. Of the 35 transplanted kidneys, 26 (74%) had immediate function, 6 (17%) had delayed graft function, and 3 (9%) were not used for other reasons. Five of the six transplanted livers had immediate function.

Evaluation of prenatal aldrin intoxication in rats.

The aim of the present study was to evaluate the impact of prenatal exposure to low doses of aldrin on physical and behavioral developments of rats (1-21 days old). To detect the possible persistent adversities produced by this exposure, the animals were also tested when adults (90 days old). Plasma determinations of both aldrin and its metabolite dieldrin and histopathological evaluations of brain slices were also performed in adult animals. Pregnant female rats were subcutaneously (s.c.) treated with aldrin (1.0 mg/kg) or with its vehicle (0.9% NaCl solution plus Tween-80) from day 1 of pregnancy until delivery. Results show that prenatal aldrin administration was able to decrease the median effective time (TE50) for incisor teeth eruption and to increase the TE50 for testes descent; other parameters indicative of physical development were not modified. Aldrin and dieldrin were not found in plasma of the adult rats; no differences were observed between control and experimental rats in the cellular and structural organization of the cerebral cortex neurones. Prenatal aldrin administration produced no impairment of adult animal's behavior in an avoidance learning test; nevertheless, the locomotor frequency of the experimental rats was higher than that of controls at 21 and 90 days old. When adults, these experimental rats had their performance in a hole-board apparatus (total number and duration of head-dips) also higher than that of the control ones. It was concluded that prenatal aldrin exposure induced not only developmental changes in the rat pups but also persistent behavioral alterations in adulthood, when the pesticide was not present in these animals.

Effects of long-term aldrin administration on seizure susceptibility of rats.

The effects of long-term administration of sub-convulsive doses of aldrin, an organochlorinated pesticide, on seizure susceptibility of rats were studied. Results show that treatment with the pesticide made the rats more susceptible to sound-induced seizures; an increment in post-seizure depression time after maximal electroshock administration was also observed in aldrin-treated animals. Aldrin administration displaced the control dose-response curves constructed for amphetamine and pentylenetetrazol to the left and right, respectively; no differences were detected between control and aldrin-treated rats for strychnine, picrotoxin or 3-mercaptopropionic acid. The results, discussed in the light of the effects of aldrin on biogenic amines or on the electrophysiology of neurones suggested an involvement of both noradrenergic and alteration excitability of the CNS with the observed increments on seizure susceptibility.

Effect of a specific stress (aldrin) on rat progeny behavior.

The effect of dam exposure to aldrin, an organochlorinated compound (1.0 mg/kg, sc, daily), during pregnancy or lactation was studied in young rat pups (11, 15, 18 and 22 days of age) and in adult animals (90 days of age). Locomotor activity was significantly greater in both young and adult animals when compared to controls. Male rats that received aldrin during lactation also showed reduced plasma corticosterone levels. Maternal behavior was not affected by treatment during either period. The results suggest that aldrin may act as a perinatal stress factor.

Effect of a specific stress (aldrin) on rat progeny behavior

The effect of dam exposure to aldrin, an organochlorinated compound (1.0 mg/Kg, sc, daily), during pregnancy or lactation was studied in young tat pups (11, 15, 18 and 22 days of age) and in adult animals (90 days of age). Locomotor activity was significantly greater in both young and adult animals when compared to contols. Male rats that received aldrin during lactation also showed reduced plasma corticosterone levels. Maternal behavior was not affected bu treatment during either period. The results sugest that aldrin may act as a perinatal stress factpr

Alterations in the behavior of young and adult rats exposed to aldrin during lactation.

The effects of the administration of aldrin, an organochlorinated pesticide, during the period of lactation were studied on behavior of the litters. The general activity of the young and adult animals was tested in an open-field. In both situations, activity was higher in experimental than in control rats. Experimental animals also showed a higher performance in a hole-board apparatus and in the shuttle-box of two-way active avoidance learning. The results suggest that the insecticide is involved in alterations occurring in the nervous/endocrine systems of the newborn.

Bowen's disease of shaft of penis. Successful treatment with 5-fluorouracil.

Bowen's disease is a precancerous lesion of the superficial layers of the skin. The topical application of 5-fluorouracil has been successfully used in the treatment of such lesions. An ususual case of Bowen's disease of the skin of the penile shaft treated successfully with topical 5-fluorouracil is presented along with a review of different modes of treatment.