Effect of cocaine on periadolescent rats with or without early maternal separation

Cocaine-induced behavioral sensitization and weight loss were investigated in periadolescent Wistar rats kept with their mothers or subjected to repeated maternal separation. Litters allocated to the separation procedure were placed in a temperature-controlled (33ºC) chamber for 3 h per day from postnatal day 6 (P6) to P20. Non-handled rats were left undisturbed until weaning. Treatments were started on P30-31 and the test was performed on P36-37. Animals received injections of saline or cocaine (10 mg/kg, sc) twice daily for 5 days. on day 6 all animals received saline. on day 7 animals were challenged with 10 mg/kg cocaine and their locomotion was evaluated in activity cages. A third group received saline throughout the 7-day period. Body weights were recorded on P30-31 and P36-37. Two-way ANOVA on body weights showed a main effect of treatment group (F(1,35) = 10.446, P = 0.003; N = 10-12). Non-handled rats treated with cocaine for 5 days gained significantly less weight, while no significant effect was observed in maternally separated rats. Two-way ANOVA revealed a main effect of drug treatment on locomotor activity (F(2,32) = 15.209, P<0.001; N = 6-8), but not on rearing condition (F(1,32)<0.001, P = 0.998). Animals pretreated with cocaine showed a clear behavioral sensitization relative to the saline group. No difference in the magnitude of sensitization was found between separated and non-handled animals. Only the effect of cocaine on weight gain was significantly affected by repeated episodes of early maternal separation during the pre-weaning period.

Chromosome polymorphism of heterochromatin and nucleolar regions in two populations of the fish Astyanax bockmanni (Teleostei: Characiformes)

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

Best practices for the implantation of ISO 14001 norms: a study of change management in two industrial companies in the Midwest region of the state of São Paulo - Brazil

Among the difficulties found in the implementation of ISO 14001 systems, resistance to change can always be found. It is mainly a consequence of the hurry to change, loss of focus, concentration of decision making at the level of top management, arbitrary imposition of objectives and results, faulty communication, and the absence of motivational and financial incentive for change.Therefore, the main objective of this paper is to present best practices with respect to the management of organizational change due to the implementation of ISO 14001 norms in two industrial companies in the Midwest region of the State of São Paulo - Brazil. (C) 2008 Elsevier Ltd. All rights reserved.

Structural aspects of the fermion-boson mapping in two-dimensional gauge and anomalous gauge theories with massive fermions

Using a synthesis of the functional integral and operator approaches we discuss the fermion-buson mapping and the role played by the Bose field algebra in the Hilbert space of two-dimensional gauge and anomalous gauge field theories with massive fermions. In QED, with quartic self-interaction among massive fermions, the use of an auxiliary vector field introduces a redundant Bose field algebra that should not be considered as an element of the intrinsic algebraic structure defining the model. In anomalous chiral QED, with massive fermions the effect of the chiral anomaly leads to the appearance in the mass operator of a spurious Bose field combination. This phase factor carries no fermion selection rule and the expected absence of Theta-vacuum in the anomalous model is displayed from the operator solution. Even in the anomalous model with massive Fermi fields, the introduction of the Wess-Zumino field replicates the theory, changing neither its algebraic content nor its physical content. (C) 2002 Elsevier B.V. (USA).

Bounded solutions of fermions in the background of mixed vector-scalar inversely linear potentials

The problem of a fermion subject to a general mixing of vector and scalar potentials in a two-dimensional world is mapped into a Sturm-Liouville problem. Isolated bounded solutions are also searched. For the specific case of an inversely linear potential, which gives rise to an effective Kratzer potential in the Sturm-Liouville problem, exact bounded solutions are found in closed form. The case of a pure scalar potential with their isolated zero-energy solutions, already analyzed in a previous work, is obtained as a particular case. The behavior of the upper and lower components of the Dirac spinor is discussed in detail and some unusual results are revealed. The nonrelativistic limit of our results adds a new support to the conclusion that even-parity solutions to the nonrelativistic one-dimensional hydrogen atom do not exist. (c) 2004 Elsevier B.V. All rights reserved.

Bounded solutions of fermions in the background of mixed vector-scalar Poeschl-Teller-like potentials

The problem of a fermion subject to a convenient mixing of vector and scalar potentials in a two-dimensional space-time is mapped into a Sturm-Liouville problem. For a specific case which gives rise to an exactly solvable effective modified Poschl-Teller potential in the Sturm-Liouville problem, bound-state solutions are found. The behaviour of the upper and lower components of the Dirac spinor is discussed in detail and some unusual results are revealed. The Dirac delta potential as a limit of the modified Poschl-Teller potential is also discussed. The problem is also shown to be mapped into that of massless fermions subject to classical topological scalar and pseudoscalar potentials. Copyright (C) EPLA, 2007.

A Beam Search Method to Solve the Problem of Assignment Cells to Switches in a Cellular Mobile Network

Assigning cells to switches in a cellular mobile network is known as an NP-hard optimization problem. This means that the alternative for the solution of this type of problem is the use of heuristic methods, because they allow the discovery of a good solution in a very satisfactory computational time. This paper proposes a Beam Search method to solve the problem of assignment cell in cellular mobile networks. Some modifications in this algorithm are also presented, which allows its parallel application. Computational results obtained from several tests confirm the effectiveness of this approach and provide good solutions for large scale problems.

Analysis of the Coupled Stretching-Bending Problem of Stiffened Plates by a BEM Formulation Based on Reissner's Hypothesis

In this work, the plate bending formulation of the boundary element method - BEM, based on the Reissner's hypothesis, is extended to the analysis of plates reinforced by beams taking into account the membrane effects. The formulation is derived by assuming a zoned body where each sub-region defines a beam or a slab and all of them are represented by a chosen reference surface. Equilibrium and compatibility conditions are automatically imposed by the integral equations, which treat this composed structure as a single body. In order to reduce the number of degrees of freedom, the problem values defined on the interfaces are written in terms of their values on the beam axis. Initially are derived separated equations for the bending and stretching problems, but in the final system of equations the two problems are coupled and can not be treated separately. Finally are presented some numerical examples whose analytical results are known to show the accuracy of the proposed model.

A BEM formulation for analysing the coupled stretching-bending problem of plates reinforced by rectangular beams with columns defined in the domain

In this work, a boundary element formulation to analyse plates reinforced by rectangular beams, with columns defined in the domain is proposed. The model is based on Kirchhoff hypothesis and the beams are not required to be displayed over the plate surface, therefore eccentricity effects are taken into account. The presented boundary element method formulation is derived by applying the reciprocity theorem to zoned plates, where beams are treated as thin sub-regions with larger rigidities. The integral representations derived for this complex structural element consider the bending and stretching effects of both structural elements working together. The standard equilibrium and compatibility conditions along interface are naturally imposed, being the bending tractions eliminated along interfaces. The in-plane tractions and the bending and in-plane displacements are approximated along the beam width, reducing the number of degrees of freedom. The columns are introduced into the formulation by considering domain points where tractions can be prescribed. Some examples are then shown to illustrate the accuracy of the formulation, comparing the obtained results with other numerical solutions.

Beta-carotene supplementation attenuates cardiac remodeling induced by one-month tobacco-smoke exposure in rats

Objective: the objectives were to analyze the cardiac effects of exposure to tobacco smoke (ETS), for a period of 30 days, alone and in combination with beta-carotene supplementation (BC). Research methods and procedures: Rats were allocated into: Air (control, n = 13); Air + BC (n = 11); ETS (n = 11); and BC + ETS (n = 9). In Air + BC and BC + ETS, 500 mg of BC were added to the diet. After three months of randomization, cardiac structure and function were assessed by echocardiogram. After that, animals were euthanized and morphological data were analyzed post-morten. One-way and two-way ANOVA were used to assess the effects of ETS, BC and the interaction between ETS and BC on the variables. Results: ETS presented smaller cardiac output (0.087 +/- 0.001 vs. 0.105 +/- 0.004 l/min; p = 0.007), higher left ventricular diastolic diameter (19.6 +/- 0.5 vs. 18.0 +/- 0.5 mm/kg; p = 0.024), higher left ventricular (2.02 +/- 0.05 vs. 1.70 +/- 0.03 g/kg; p < 0.001) and atrium (0.24 +/- 0.01 vs. 0.19 +/- 0.01 g/kg; p = 0.003) weight, adjusted to body weight of animals, and higher values of hepatic lipid hydroperoxide (5.32 +/- 0.1 vs. 4.84 +/- 0.1 nmol/g tissue; p = 0.031) than Air. However, considering those variables, there were no differences between Air and BC + ETS (0.099 +/- 0.004 l/min; 19.0 +/- 0.5 mm/kg; 1.83 +/- 0.04 g/kg; 0.19 +/- 0.01 g/kg; 4.88 +/- 0.1 nmol/g tissue, respectively; p > 0.05). Ultrastructural alterations were found in ETS: disorganization or loss of myofilaments, plasmatic membrane infolding, sarcoplasm reticulum dilatation, polymorphic mitochondria with swelling and decreased cristae. In BC + ETS, most fibers showed normal morphological aspects. Conclusion: One-month tobacco-smoke exposure induces functional and morphological cardiac alterations and BC supplementation attenuates this ventricular remodeling process.

Ascorbic acid supplementation has a cytoprotective effect on secondary biliary cirrhosis: experimental study in young rats

Objective: To test whether ascorbic acid supplementation has any cytoprotective effect on a model of secondary biliary cirrhosis in young rats.Methods: We studied 40 Wistar rats weaned at the 21st postnatal day. Each group of 10 was subjected to one of the following four treatments, until 49th postnatal day, when they suffered euthanasia: 1) LC-double ligature and resection of the common bile duct and daily administration of ascorbic acid [100 mg/g of body weight (bw)]; 2) LA-double ligature and resection of the common bile duct and daily administration of aqueous vehicle (1 mL/g bw); 3) SC-sham operation and daily administration of ascorbic acid (100 mg/g bw); 4) SA-double ligature and resection of the common bile duct and daily administration of aqueous vehicle (1 mL/g bw). The rats were weighed daily. on the 27th day after the operation they received an intra-peritoneal injection of 1.5 mg/g bw of sodium pentobarbital, and the pentobarbital sleeping time was measured. Blood was collected for serum alanine aminotransferase and aspartate aminotransferase activity measurements, serum albumin and globulin concentrations, and the liver was assessed for liver water and fat content. Data were submitted to two-way ANOVA and paired comparisons between groups were tested using the SNK method. Significance level was set at 0.05.Results: Ascorbic acid supplementation attenuated the effects of cholestasis: decreased the pentobarbital sleeping time, serum globulin, and the liver fat content.Conclusions: Our results corroborate the hypothesis that ascorbic acid supplementation has a cytoprotective effect in secondary biliary cirrhosis.

Magnetic resonance imaging in the diagnosis of type 1 dermoid sinus in two Rhodesian ridgeback dogs

Two cases of type 1 dermoid sinus in Rhodesian ridgebacks are described, with emphasis on the use of magnetic resonance imaging (MRI) in the diagnosis and delineation of the lesions. Magnetic resonance imaging was useful in identifying fluid-filled structures, fibrous capsules, and sinus tracts, but was not able to identify the termination of the tracts.

Prevalence of dementia in Latin America: a collaborative study of population-based cohorts

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

Hepatoprotective effect of water soluble extract of Coleus barbatus on cholestasis on young rats

OBJETIVO: Testar os efeitos do extrato aquoso de Coleus barbatus (EAB) na cirrose biliar secundária por obstrução das vias biliares extra-hepáticas em ratos jovens. MÉTODOS: Quarenta ratos Wistar machos com 21 dias de vida (P21), foram distribuídos em quatro grupos de 10 animais, submetidos a operação simulada ou dupla ligadura e ressecção do ducto biliar (S ou L) combinados EAB e a Água (B ou A). No P48, foi medido o tempo de sono com o pentobarbital (TS). No P49, foram submetidos a eutanásia para a determinação das atividades séricas do aspartato aminotransferase (AST) e da alanina aminotransferases (ALT); após a eutanásia foram avaliados o peso fresco do fígado (PFF) e, em cortes histológicos do fígado, a freqüência de mitoses (FM), o número de áreas de necrose (NN), a intensidade da fibrose (IF) e da proliferação ductal (IPD). Os efeitos da colestase, os do EAB e suas interações foram testados pela ANOVA com dois fatores, e as comparações múltiplas pareadas foram realizadas pelo teste de S.N.K ou teste de Wilcoxon. Também foi determinada a correlação linear de Pearson entre as variáveis histológicas duas a duas separadamente para os grupos LA e LD. O nível de significância estatística para os vários testes foi de p do erro alfa <0,05. RESULTADOS: A colestase aumentou significativamente o TS, a ALT, a AST, o PFF, a MI, o NN, a IF e a IPD. O EAB diminuiu o TS e a IM nos animais sem colestase (operação simulada). O EAB diminuiu o TS, a ALT, a AST, o PFF, a MI, o NN e IF na colestase. No grupo LA houve correlação positiva entre a IPD e a IF, correlação negativa entre a IPD e a FM e correlação negativa entre a IF a FM. No grupo LD houve correlação negativa entre o NN e a IPD. CONCLUSÕES: Na ausência de colestase o EAB encurta o tempo de sono e diminui a freqüência de mitoses. O EAB apresenta efeito hepatoprotetor no modelo de cirrose biliar secundária a obstrução biliar extra-hepática.