RESUMO

Synthetic type II pyrethroids induce anxiety, immunosuppression or, alternatively, immunostimulatory effects in laboratory animals. Macrophages and neutrophils are known to be key elements in cellular immune responses. The present study was designed to investigate the in vivo effects of cyhalothrin (1.0 and 3.0 mg/kg/once daily for 7 days) on macrophage and neutrophil activities, using a flow cytometry method. Results showed that cyhalothrin treatment decreased the percentage and intensity of phagocytosis performed by macrophages, but did not alter these parameters in neutrophils; and also decreased basal neutrophil oxidative burst and increased S. aureus-induced neutrophil oxidative burst, but did not alter these responses in macrophages. The present results are discussed in the light of a possible indirect action of cyhalothrin on macrophage and neutrophil activities via hypothalamic pituitary adrenal (HPA) axis activation. A possible direct effect of cyhalothrin on macrophage and neutrophil activities is also considered.

Assuntos

RESUMO

Synthetic type II pyrethroid insecticides, such as cyhalothrin at certain dosage levels, simultaneously induce stress-like symptoms and innate immunosuppressive effects in laboratory animals. The present study was designed to further analyze the stress-like effects induced by cyhalotrin and also investigate the role of Hypothalamus-Hypophysis-Adrenal (HHA) axis and Sympathetic Nervous Systems (SNS) and their effects on macrophage activity of rats. Results showed that cyhalothrin treatment (3.0mg/kg/day, for 7 days) increased corticosterone serum levels and c-fos immunoreactivity at the paraventricular nucleus of the hypothalamus (PVN) but induced no changes in c-fos expression at the basolateral amygdala (BLA). Both areas were related to HHA axis and SNS activations by stress. Further analysis showed that adrenalectomy partially abrogated the suppression effects of cyhalothrin on macrophage activity and that 6-OHDA-induced peripheral symphatectyomy had no effects on this innate immune cell activity. The present observed data support and reinforce the notion that cyhalotrin at this treatment schedule induces stress-like symptoms and suggest that other factors, beyond indirect neuroadaptative responses, are necessary for the suppression effects of insecticide on innate immune response.

RESUMO

This study evaluated the effects of systemic progesterone concentration on oocyte quality and in vitro embryo production. Oocytes were retrieved from 15 crossbred cows (Bos taurus x Bos indicus). These cows were randomly allocated into three groups to provide low; high, or very low (LP4, HP4 and VLP4, respectively) plasma progesterone concentrations and received either a previously used CIDR, two new CIDR devices, or no progesterone treatment (Day 0). The CIDR devices were replaced every 8 days along with 150 µg of D-cloprostenol injections. The ovum pick-up (OPU) procedure was performed every 4 days from Day 4 to 24. Simultaneous to OPU procedure, plasma was collected to measure progesterone and on Day 18, serial blood samples were collected to assess the pattern of LH release. Hormone concentrations were analyzed by ANOVA and the binomial variables were analyzed by Chi-square. Plasma progesterone concentration was higher in the HP4, intermediate in the LP4, and lower in the VLP4 group (3.6, 1.6, and 0.5 ng/ml; P < 0.05). Plasma LH was higher in the LP4, intermediary in the VLP4, and lower in the HP4 group (1.6, 1.0, and 0.8 ng/ml). A greater percentage of viable oocytes (grades I to III) was retrieved from LP4 (79.4%; 131/165) than from the HP4 (68.4%; 119/174) group (P = 0.07); the VLP4 group did not differ from the others (72.3%; 60/83). Furthermore, the blastocyst production and blastocyst rate was higher in LP4 (1.3 ± 0.4; 28.2%), than in HP4 (0.8 ± 0.4; 16.0%) or the VLP4 (0.4 ± 0.4; 15.0%) group (P = 0.06 and 0.03 for blastocyst production and rate, respectively). In conclusion, intermediate plasma P4 concentration that results in higher circulating LH in cows may improve in vitro embryo production.(AU)

Assuntos

RESUMO

This study evaluated the effects of systemic progesterone concentration on oocyte quality and in vitro embryo production. Oocytes were retrieved from 15 crossbred cows (Bos taurus x Bos indicus). These cows were randomly allocated into three groups to provide low; high, or very low (LP4, HP4 and VLP4, respectively) plasma progesterone concentrations and received either a previously used CIDR, two new CIDR devices, or no progesterone treatment (Day 0). The CIDR devices were replaced every 8 days along with 150 µg of D-cloprostenol injections. The ovum pick-up (OPU) procedure was performed every 4 days from Day 4 to 24. Simultaneous to OPU procedure, plasma was collected to measure progesterone and on Day 18, serial blood samples were collected to assess the pattern of LH release. Hormone concentrations were analyzed by ANOVA and the binomial variables were analyzed by Chi-square. Plasma progesterone concentration was higher in the HP4, intermediate in the LP4, and lower in the VLP4 group (3.6, 1.6, and 0.5 ng/ml; P < 0.05). Plasma LH was higher in the LP4, intermediary in the VLP4, and lower in the HP4 group (1.6, 1.0, and 0.8 ng/ml). A greater percentage of viable oocytes (grades I to III) was retrieved from LP4 (79.4%; 131/165) than from the HP4 (68.4%; 119/174) group (P = 0.07); the VLP4 group did not differ from the others (72.3%; 60/83). Furthermore, the blastocyst production and blastocyst rate was higher in LP4 (1.3 ± 0.4; 28.2%), than in HP4 (0.8 ± 0.4; 16.0%) or the VLP4 (0.4 ± 0.4; 15.0%) group (P = 0.06 and 0.03 for blastocyst production and rate, respectively). In conclusion, intermediate plasma P4 concentration that results in higher circulating LH in cows may improve in vitro embryo production.

Assuntos

RESUMO

Avaliou-se a cromatografia em camada delgada (CCD) como método de diagnóstico toxicológico para os casos de intoxicação por aldicarb em cães e gatos, utilizando-se 50 amostras de conteúdo gástrico obtidas durante a necropsia e 50 amostras de alimentos utilizados como iscas para intoxicar criminalmente os animais. Todas as amostras resultaram positivas para o aldicarb, mostrando ser a CCD uma técnica qualitativa eficiente, rápida e de baixo custo, com uso potencial na toxicologia veterinária forense(AU)

The present study concerns about the identification of aldicarb residues using thin-layer chromatography (TLC) in 50 samples of gastric content obtained from the necropsy of dogs and cats and 50 samples of foods suspected of being used as baits. All samples resulted positive for aldicarb showing that the TLC is an efficient, fast and not expensive qualitative method for the detection of aldicarb, being useful for this purpose in the forensic veterinary toxicology(AU)

Assuntos

RESUMO

Avaliou-se a cromatografia em camada delgada (CCD) como método de diagnóstico toxicológico para os casos de intoxicação por aldicarb em cães e gatos, utilizando-se 50 amostras de conteúdo gástrico obtidas durante a necropsia e 50 amostras de alimentos utilizados como iscas para intoxicar criminalmente os animais. Todas as amostras resultaram positivas para o aldicarb, mostrando ser a CCD uma técnica qualitativa eficiente, rápida e de baixo custo, com uso potencial na toxicologia veterinária forense

The present study concerns about the identification of aldicarb residues using thin-layer chromatography (TLC) in 50 samples of gastric content obtained from the necropsy of dogs and cats and 50 samples of foods suspected of being used as baits. All samples resulted positive for aldicarb showing that the TLC is an efficient, fast and not expensive qualitative method for the detection of aldicarb, being useful for this purpose in the forensic veterinary toxicology

Assuntos

RESUMO

The present study concerns about the identification of aldicarb residues using thin-layer chromatography (TLC) in 50 samples of gastric content obtained from the necropsy of dogs and cats and 50 samples of foods suspected of being used as baits. All samples resulted positive for aldicarb showing that the TLC is an efficient, fast and not expensive qualitative method for the detection of aldicarb, being useful for this purpose in the forensic veterinary toxicology.

Avaliou-se a cromatografia em camada delgada (CCD) como método de diagnóstico toxicológico para os casos de intoxicação por aldicarb em cães e gatos, utilizando-se 50 amostras de conteúdo gástrico obtidas durante a necropsia e 50 amostras de alimentos utilizados como iscas para intoxicar criminalmente os animais. Todas as amostras resultaram positivas para o aldicarb, mostrando ser a CCD uma técnica qualitativa eficiente, rápida e de baixo custo, com uso potencial na toxicologia veterinária forense.