Absence of DNA damage in multiple organs (blood, liver, kidney, thyroid gland and urinary bladder) after acute fluoride exposure in rats

Fluoride has been widely used in dentistry as a caries prophylactic agent. However, there has been some speculation that excess fluoride could cause an impact on genome integrity. In the current study, the potential DNA damage associated with exposure to fluoride was assessed in cells of blood, liver, kidney, thyroid gland and urinary bladder by the single cell gel (comet) assay. Male Wistar rats aging 75 days were distributed into seven groups: Groups 1 (control), 2, 3, 4, 5, 6 and 7 received 0 (deionized water), 10, 20, 40, 60, 80 and 100 mgF/Kg body weight from sodium fluoride (NaF), respectively, by gastrogavage. These groups were killed at 2 h after the administration of the fluoride doses. The level of DNA strand breaks did not increase in all organs evaluated and at all doses of NaF tested, as depicted by the mean tail moment. Taken together, our results suggest that oral exposure to NaF did not result in systemic genotoxic effect in multiple organs related to fluoride toxicity. Since DNA damage is an important step in events leading to carcinogenesis, this study represents a relevant contribution to the correct evaluation of the potential health risk associated with chemical exposure.

DNA damage in multiple organs after exposure to chlorhexidine in Wistar rats

Since chlorhexidine is effective against microorganisms, it is widely recommended in dentistry. However, studies have provided evidence that chlorhexidine is toxic for a variety of cell types. In order to identify potential genotoxins in different cell types, the purpose of this study was to investigate whether chlorhexidine digluconate is able to cause, in terms of DNA damage, alterations in leukocytes, liver, kidney and urinary bladder by the single cell gel (comet) assay. Ten male Wistar rats were divided into two groups: a negative control and the experimental group treated with 3 ml of 0.12% chlorhexidine digluconate by gavage once a day for 8 days. Statistically significant increases of DNA damage was observed in leukocytes and kidney cells of the chlorhexidine digluconate treated group as depicted by the mean tail moment. Taken together, the data indicate that leukocytes and kidney cells are potential targets for primary DNA damage following oral exposure to chlorhexidine digluconate as detected by single cell gel (comet) assay. (c) 2006 Elsevier GmbH. All rights reserved.

EFFECTS of DIURON on MALE RAT REPRODUCTIVE ORGANS: A DEVELOPMENTAL and POSTNATAL STUDY

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

Systemic evaluation on ischemia and reperfusion injury of splanchnic organs in rats

OBJETIVO: Avaliar as alterações hemodinâmicas e sistêmicas decorrentes de isquemia e reperfusão (I/R) esplâncnica em ratos. MÉTODOS: Vinte ratos foram divididos em dois grupos: grupo controle: os animais foram submetidos à cirurgia, mas não a I/R e foram tratados com solução fisiológica (5 ml/kg/h) por 150 minutos; grupo I/R: os animais foram submetidos à administração contínua de solução fisiológica e à oclusão do tronco celíaco, artéria mesentérica superior e artéria mesentérica inferior por 30 minutos, seguidos por 120 minutos de reperfusão. Avaliou-se a pressão arterial média, pressão venosa, fluxo sangüíneo na aorta e na artéria mesentérica superior, freqüência cardíaca, temperatura esofágica e hematócrito. RESULTADOS: Durante a reperfusão, no grupo I/R, houve uma diminuição progressiva da pressão arterial média, fluxo sangüíneo na aorta e artéria mesentérica superior, freqüência cardíaca e temperatura esofágica; pressão venosa e hematócrito não sofreram alteração. CONCLUSÃO: O modelo de isquemia provocado por oclusão da artéria mesentérica superior, artéria mesentérica inferior e tronco celíaco por 30 minutos seguidos por 120 minutos de reperfusão provoca alterações sistêmicas evidenciadas por hipotensão, diminuição do fluxo sangüíneo mesentérico, da freqüência cardíaca e da temperatura esofágica.

Adaptation and evaluation of polymerase chain reaction for Brucella ovis detection in semen, urine and organs of rams experimentally infected

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

Morphological changes of the intestinal mucosa of broilers and layers as affected by fasting before sample collection

The present study aimed at evaluating the histo-morphological changes resulting from different fasting periods before the collection of tissue samples in different segments of the small intestine (duodenum, jejunum and ileum) of 7-d-old male chicks of a broiler and a layer strain. A completely randomized experimental design in in a 2x7 factorial arrangement, being two strains with different growth rates (Ross 308 and HyLine® W36) and seven fasting periods (0, 2, 4, 6, 8, 10 and 12 hours ), with six replicates, totaling 84 birds. The comparison of the morphometrics of the duodenum, jejunum and ileum of broiler and layer chicks demonstrated faster digestive tract development in broilers relative to layers. The fasting period caused morphological changes in the liver and small and large intestines in both strains. Therefore, it must be highlighted that in studies involving organ weights and intestinal morphometrics, birds must not be submitted to fasting before tissue collection.

Green Brazilian propolis action on macrophages and lymphoid organs of chronically stressed mice

Stress is a generic term that summarizes how psychosocial and environmental factors influence physical and mental well-being. The interaction between stress and immunity has been widely investigated, involving the neuroendocrine system and several organs. Assays using natural products in stress models deserve further investigation. Propolis immunomodulatory action has been mentioned and it has been the subject of scientific investigation in our laboratory. The aim of this study was to evaluate if and how propolis activated macrophages in BALB/c mice submitted to immobilization stress, as well as the histopathological analysis of the thymus, bone marrow, spleen and adrenal glands. Stressed mice showed a higher hydrogen peroxide (H2O2) generation by peritoneal macrophages, and propolis treatment potentiated H2O2 generation and inhibited nitric oxide (NO) production by these cells. Histopathological analysis showed no alterations in the thymus, bone marrow and adrenal glands, but increased germinal centers in the spleen. Propolis treatment counteracted the alterations found in the spleen of stressed mice. New research is being carried out in order to elucidate propolis immunomodulatory action during stress.

Exercise preconditioning modulates genotoxicity induced by doxorubicin in multiple organs of rats

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ultramorphology of digestive tract of Anticarsia gemmatalis (Hubner, 1818) (Lepidoptera : Noctuidae) at final larval development

The digestive tract of insects is an important natural, physical, and chemical defense barrier against pathogen invasion. Certain. lepidopteran caterpillars are serious pests of agricultural crops and their biology has received much attention, but little is known about the larval noctuid gut. The morphological analysis of the digestive tract in Anticarsia gemmatalis under scanning electron microscopy (SEM) is a good model for studies about its defense mechanism. The material was fixed (2,5% glutaraldehyde solution; 0.1 M-phosphate buffer, pH 7.3), post-fixed (1% osmium tetroxide in the same buffer), dried at critical point, gold coated and analyzed in a SEM 515-Philips. A. gemmatalis digestive tract consists of a straight duct of varying length and diameter, subdivided in three main regions: the foregut formed by the oral cavity, pharynx, esophagus, and crop; the midgut that is the largest portion of the digestive tract without noticeable morphological differentiation along its length; and the hindgut that is morphologically differentiated in pylorus, ileum, colon, and rectum. Although the general morphology of the A. gemmatalis digestive tract is quite similar to the other Lepidoptera species, the anatomical array of the crop muscular layers is quite different comparing with the description for other larval insect.

Ultramorphology of the Digestive Tract of Paratrechina longicornis (Hymenoptera, Formicidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Helminths From an Introduced Species (Tupinambis merianae), and Two Endemic Species (Trachylepis atlantica and Amphisbaena ridleyi) From Fernando de Noronha Archipelago, Brazil

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

Ontogenetic shifts in the digestive tube and diet of Bryconamericus stramineus Eigenmann, 1908 (Osteichthyes, Characidae)

Aim: Studies on feeding of early life stages are very important to the understanding of the biology and trophic ecology of fish species. Therefore, the aim of this work is to describe the development of the digestive tube, and to characterize the diet of larvae and juveniles of Bryconamericus stramineus Eigenmann, 1908 of the upper Parana River floodplain; Methods: Larvae were obtained from, monthly samples during nychthemeral cycles with four-hour interval between samplings from February/91 to February/92, utilizing a conical-cylindrical plankton net; Results: At the preflexion stage, larvae at approximately 4.00 mm SL, showed a morphologically undifferentiated straight tube, with the anterior region more dilated. At the flexion stage a differentiation in the anterior region of the digestive tube occurs, with the intestine wall getting thicker (8.30 mm SL). The formation of pyloric caeca occurs at 9.00 mm SL. At the postflexion stage the first loop is formed at 9.25 mm SL and the second loop at about 10.00 mm SL. Bryconamericus stramineus consumed mainly cladocerans, also ingesting copepods, rotifers, nematodes, algae, insects and inorganic particles. Along the development, there was an increase in the number of food items and a diversification in the number of consumed taxa; Conclusions: Changes in the diet of B. stramineus larvae were not observed, being them zooplanktivores during all the initial development. However, an increase of large preys, such as insects larvae, was observed at the end of the larval period and in juveniles, suggesting a tendency towards invertivory. Larvae and juveniles preferentially fed during the night.

Comparative anatomy of the male reproductive internal organs of 51 species of bees

A anatomia dos órgãos internos do aparelho reprodutor de machos (ARM) adultos e pupas foi comparada em 51 espécies de abelhas, incluindo representantes de seis famílias. Foram obtidos quatro tipos diferentes de ARM. O tipo I está presente em machos das famílias mais basais (Colletidae, Andrenidae e Halictidae) e é caracterizado por três túbulos seminíferos por testículo, o qual é quase totalmente envolvido pela membrana escrotal. O tipo II é um tipo intermediário entre os tipos I e III e está presente em Mellitidae e Megachilidae, como também em alguns Apidae estudados, sendo caracterizado por possuir dutos deferentes pós-vesiculares fora da membrana escrotal e possuir três ou quatro túbulos seminíferos por testículo, exceto Apis mellifera L., a qual possui secundariamente um número aumentado de túbulos. O tipo III foi achado somente nos Apidae estudados e é caracterizado por apresentar os testículos e dutos genitais (exceto o duto deferente pós-vesicular) encapsulados separadamente, as glândulas acessórias são bem desenvolvidas e o duto ejaculador é calibroso, apresentando fissuras em sua parede externa, as quais podem ocorrer também no tipo II. O tipo IV está presente exclusivamente na tribo Meliponini e é caracterizado pela ausência de glândulas acessórias.

First report of endocytobionts in the digestive tract of ponerine ants

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