Effect of root canal filling material and level of surgical injury on periodontal healing in dogs

Some divergencies in the literature about periodontal healing after surgical injury stimulated the development of this experiment. The root canals of dogs' teeth were negotiated and filled by the lateral condensation technique with two kinds of sealers: Sealapex and zinc oxide-eugenol cement. In the second session, the bone tissue was exposed and one cavity was made at the apical third of the root and another at the border between the coronal and middle thirds, both penetrating into the root canal. Six months later the animals were sacrificed and the specimens prepared for histopathologic analysis. The results showed that the kind of filling material and the level of the periodontal wound exposing the root canal can influence the healing process (P<0.01).

Investigations on the new free radical scavenger polynitroxyl-albumin to prevent ischemia and reperfusion injury after orthotopic heart transplantation in the pig model

Objective: Nitroxides have strong antioxidant capacity but their effectiveness is limited by their rapid intracellular inactivation. Poly nitroxyl-Albumin (PNA) is capable of regenerating inactivated nitroxide. We tested the effect of PNA against reperfusion injury in heart transplantation. Methods: Pig hearts were transplanted orthotopically. In the control group (n = 9) reperfusion was performed without reperfusion modifications. In the experimental group (n = 10) 1 ml/kg PNA was given before cross-clamp release. Results: Hemodynamic performance was impaired after transplantation in both groups without significant intergroup differences. Plasma malonedialdehyde levels were significantly diminished in the PNA group as compared to the controls. CK-MB levels in both groups were increased within the first 2 h of reperfusion without significant intergroup differences. In contrast, there were found significant higher values of myocardial specific lactate dehydrogenase (LD1) in the controls versus PNA group. Conclusions: PNA was able to reduce lipid peroxidation and attenuate free radical activity. Contractile dysfunction could no be improved, indicating that (a) the radical scavenging effect was to weak or (b) other mechanisms than free oxygen radicals are responsible for myocardial damage in this experimental model. (C) 2001 Elsevier B.V. B.V. All rights reserved.

Occurrence of severe and moderate traumatic brain injury in patients attended in a Brazilian teaching hospital - Epidemiology and dosage of alcoholemy

This study aimed at observing aspects of epidemiology in order to investigate the use of alcohol in patients older than 18 with severe and moderate traumatic brain injury, which were attended in the Clinics Hospital of the University of Uberlandia. Positive alcoholemy was found in 39.3% of the patients. of the 33 positive exams alcoholemy was found higher than 60 mg/dL in 28 (84.6%). There was not significant relation between alcoholemy levels and trauma severity. The major prevalence occurred on Saturdays nights. The most frequent types of external causes were transportation accidents (64.74) followed by accidental falls (17.27%) and physical aggression (16.55%). 93.9% of the patients with positive alcoholemy were men aged 20-29. 24.2% of the ones with positive alcoholemy died yet no significant difference was found in the study of the ones with negative alcoholemy (n=51) (p=0.93); RR= 0.9; IC95%=0.40-2.08.

Origin of nuclear and chromosomal alterations derived from the action of an aneugenic agent-Trifluralin herbicide

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Chlorophyll fluorescence as a marker for herbicide mechanisms of action

Photosynthesis is the single most important source of 02 and organic chemical energy necessary to support all non-autotrophic life forms. Plants compartmentalize this elaborate biochemical process within chloroplasts in order to safely harness the power of solar energy and convert it into usable chemical units. Stresses (biotic or abiotic) that challenge the integrity of the plant cell are likely to affect photosynthesis and alter chlorophyll fluorescence. A simple three-step assay was developed to test selected herbicides representative of the known herbicide mechanisms of action and a number of natural phytotoxins to determine their effect on photosynthesis as measured by chlorophyll fluorescence. The most active compounds were those interacting directly with photosynthesis (inhibitors of photosystem I and II), those inhibiting carotenoid synthesis, and those with mechanisms of action generating reactive oxygen species and lipid peroxidation (uncouplers and inhibitors of protoporphyrinogen oxidase). Other active compounds targeted lipids (very-long-chain fatty acid synthase and removal of cuticular waxes). Therefore, induced chlorophyll fluorescence is a good biomarker to help identify certain herbicide modes of action and their dependence on light for bioactivity. Published by Elsevier B.V.

Use of Biopolymeric Membranes for Adsorption of Paraquat Herbicide from Water

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

Poly(hydroxybutyrate-co-hydroxyvalerate) microspheres loaded with atrazine herbicide: screening of conditions for preparation, physico-chemical characterization, and in vitro release studies

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

Acute exposure of a glyphosate-based herbicide affects the gills and liver of the Neotropical fish, Piaractus mesopotamicus

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

Mutagenic and genotoxic effects of the Atrazine herbicide in Oreochromis niloticus (Perciformes, Cichlidae) detected by the micronuclei test and the comet assay

Atrazine is the triazinic herbicide most found in the rural aquatic environments due to its extensive use and its stability in such places. The mutagenicity and the genotoxicity of different concentrations of the Atrazine herbicide were determinated by the micronucleus test and the comet assay, using Oreochromis niloticus as test-system. The tested concentrations of Atrazine herbicide were 6.25, 12.5 and 25 mu g/L, both for the micronuclei test and for the comet assay. The results showed a significant rate of micronuclei and nuclear abnormalities for all the tested concentrations of Atrazine herbicide. For the comet assay, we also observed results significantly different from the control in 6.25, 12.5 and 25 mu g/L concentrations. Due to these results, we could infer that such herbicide may be dangerous to the lives of those organisms exposed to it. (c) 2007 Elsevier B.V. All rights reserved.

Acute, subchronic and chronic 2,4-dichlorophenoxyacetic acid (2,4-D) intoxication in rats

The acute, subchronic and chronic toxicities of 2,4- dichlorophenoxyacetic acid (2,4-D) were studied in rats. Animals were exposed acutely (600 mg/kg), subchronically (200 ppm for 30 d) and chronically (200 ppm for 180 d) to 2,4-D by the oral route. Clinical, laboratory and histopathological methods were used as indicators of toxicity. After acute exposure, the herbicide decreased locomotor activity and induced ataxia, sedation, muscular weakness (mainly of the hind quarters) and gasping for breath; increased aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), alkaline phosphatase (AP), amylase activities and creatinine levels; decreased total protein (TP) and glucose levels; and increased hematocrit values. Subchronic and chronic 2,4-D exposures did not induce overt clinical signs or symptoms of intoxication. However, subchronic herbicide exposure increased AST activity and albumin and hematocrit values, and chronic exposure increased AST, AP and LDH activities, decreased amylase and glucose levels, but did not change hematocrit values. Chromatographic analysis of the serum of chronically exposed rats showed the presence of the herbicide; the amount found (3.76 ± 1.16 mg/ml) suggested the absence of 2,4-D accumulation within the body. Although macroscopic or histopathological lesions were not observed in acutely, subchronically or chronically 2,4-D exposed rats, the laboratory data obtained suggest tissue injuries after dosing, since the results are considered early indicators of primarily hepatic and muscle tissue damage.

Effect of α-tocopherol, taurine and selenium on the attenuation of ischemia/reperfusion injury of splanchnic organs

Background: Splanchnic artery occlusion shock is caused by increased capillary permeability and cellular injury precipitated by oxygen derived free radicals following ischemia and reperfusion of splanchnic organs. The purpose of this study was to assess the role of several well-known oxygen- derived free radical scavengers in ameliorating or preventing this syndrome. Study design: Anesthetized rats were subjected to periods of occlusion of the visceral arteries and reperfusion. Tocopherol, taurine, selenium or a 'cocktail' of these three agents was injected subcutaneously for 4 consecutive days prior to operation. Mean arterial blood pressure was measured throughout the experimental period. Fluorometry and technetium-99m pyrophosphate counting of the visceral organs were performed as well as a histologic grading system for intestinal viability. Results: Final mean arterial blood pressure associated with the 'cocktail' and selenium groups was 79.1 ± 27.4 mmHg and 83.6 ± 17.8 mmHg, respectively. These values were significantly higher than the control group, 40.8 ± 11.4 mmHg (P < 0.05). Similar patterns of the benefit of selenium in contrast with the other groups were obtained with fluorescein perfusion, radioisotopic activity and histologic analysis. Conclusion: Pretreatment with selenium of splanchnic ischemia and reperfusion in the rat improves mean arterial blood pressure and microcirculatory visceral perfusion. Further analysis of the precise protective mechanism of selenium for reperfusion injury will enable visceral organs to withstand the consequences of increased capillary leakage and oxidant injury.