Effects of sublethal dose of fipronil on neuron metabolic activity of africanized honeybees

Fipronil is a neurotoxic insecticide that inhibits the gamma-aminobutyric acid receptor and can affect gustative perception, olfactory learning, and motor activity of the honeybee Apis mellifera. This study determined the lethal dose (LD50) and the lethal concentration (LC50) for Africanized honeybee and evaluated the toxicity of a sublethal dose of fipronil on neuron metabolic activity by way of histochemical analysis using cytochrome oxidase detection in brains from worker bees of different ages. In addition, the present study investigated the recovery mechanism by discontinuing the oral exposure to fipronil. The results showed that mushroom bodies of aged Africanized honeybees are affected by fipronil, which causes changes in metabolism by increasing the respiratory activity of mitochondria. In antennal lobes, the sublethal dose of fipronil did not cause an increase in metabolic activity. The recovery experiments showed that discontinued exposure to a diet contaminated with fipronil did not lead to recovery of neural activity. Our results show that even at very low concentrations, fipronil is harmful to honeybees and can induce several types of injuries to honeybee physiology. © 2012 Springer Science+Business Media New York.

Immunomodulatory effects of low dose chemotherapy and perspectives of its combination with immunotherapy

Given that cancer is one of the main causes of death worldwide, many efforts have been directed toward discovering new treatments and approaches to cure or control this group of diseases. Chemotherapy is the main treatment for cancer; however, a conventional schedule based on maximum tolerated dose (MTD) shows several side effects and frequently allows the development of drug resistance. On the other side, low dose chemotherapy involves antiangiogenic and immunomodulatory processes that help host to fight against tumor cells, with lower grade of side effects. In this review, we present evidence that metronomic chemotherapy, based on the frequent administration of low or intermediate doses of chemotherapeutics, can be better than or as efficient as MTD. Finally, we present some data indicating that noncytotoxic concentrations of antineoplastic agents are able to both up-regulate the immune system and increase the susceptibility of tumor cells to cytotoxic T lymphocytes. Taken together, data from the literature provides us with sufficient evidence that low concentrations of selected chemotherapeutic agents, rather than conventional high doses, should be evaluated in combination with immunotherapy. Copyright © 2012 UICC.

Poly [1,1'-bis(ethynyl)-4,4'-biphenyl(bis-tributylphosphine)Pt(II)] solutions used as low dose ionizing radiation dosimeter

In this work, the effect of gamma radiation on the optical properties of polymetallayne poly[1,1'-bis(ethynyl)-4,4'-biphenyl(bis-tributylphosphine)Pt(II) ] (Pt-DEBP) in chloroform solution is studied. The samples were irradiated at room temperature with doses from 0.01 Gy to 1 Gy using a 60Co gamma ray source. A new band at 420 nm is observed in the emission spectra, in superposition to the emission maximum at 398 nm, linearly dependent on dose. We propose to use the ratio of the emission amplitude bands as the dosimetric parameter. This method proved to be robust, accurate, and can be used as a dosimeter in medical applications. © 2013 AIP Publishing LLC.

Dose-response of diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] in the urothelial mucosa of Wistar rats

Diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] is a herbicide that induced urothelial tumors in the urinary bladder of Wistar rats fed 2500. ppm during a long-term study. The currently suggested non-genotoxic mode of action (MOA) of diuron encompasses in succession urothelial necrosis induced by direct cytotoxicity, regenerative cell proliferation and sustained urothelial hyperplasia that increases the likelihood of neoplasia development. This study evaluated the dose-response profile of urothelial histological and ultrastructural lesions induced by diuron. Sixty male Wistar rats were fed ad libitum diuron mixed in the diet at 0, 60, 125, 500, 1250, or 2500. ppm for 20 weeks. The incidences of urothelial simple hyperplasia and the cell proliferation index were significantly increased in the diuron-fed 1250 and 2500. ppm groups. By scanning electron microscopy, the incidences and severity of lesions were significantly increased in the 500 and 1250. ppm groups. The incidences of urothelial hyperplasia in the kidney pelvis were significantly increased in the 500, 1250 and 2500. ppm groups. The present study documents the dose-response influence of diuron on the rat urothelium, with a no observed effect level (NOEL) at 125. ppm; 1250. ppm was as effective as 2500. ppm at inducing urothelial lesions. © 2013 Elsevier B.V.

Proposta de metodologia para o gerenciamento de fonte radioativa e estimativa de dose efeiva em pacientes submetidos à terapia com iodeto de sódio I-131

Pós-graduação em Pesquisa e Desenvolvimento (Biotecnologia Médica) - FMB

Estudo da segurança da dose terapêutica oral do firocoxib em equinos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Expressão de CD45+ na medula óssea e sangue periférico de cães com linfoma tratados com alta dose de ciclofosfamida suportada por transplante autólogo de medula óssea

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação comparativa das técnicas de ELISA indireto, antígeno acidificado tamponado, 2-mercaptoetanol com soroaglutinação lenta e fixação de complemento para o diagnóstico da brucelose em rebanho bovino não vacinado, rebanho vacinado com dose padrão e rebanho vacinado com dose reduzida da amostra 19 de Brucella abortus

Pós-graduação em Medicina Veterinária - FMVZ

Dose ótima econômica de nitrogênio em cana-de-açúcar aplicada via fertirrigação por gotejamento

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Desenvolvimento e produção de Costus productus Maas como planta de vaso em função de doses de nitrogênio

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Efeitos do treinamento físico prévio sobre a severidade do diabetes induzido por dose única de aloxana em ratos

Pós-graduação em Ciências da Motricidade - IBRC

Metodologia para determinar a relação dose-resposta de produtos fluoretados utilizando esmalte bovino e modelo de ciclagem de pH

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo dose-resposta do herbicida diuron[3-(3,4-diclorofenil)-1,1-dimetiluréia] no epitélio da bexiga de ratos Wistar machos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito do meio e da dose inseminação sobre a congelabilidade e fertilidade de espermatozóides recuperados da cauda do epidídimo de garanhões

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Resposta ovariana em éguas tratadas com baixa dose de extrato de pituitária equina

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)