Histopathological analysis of the reproductive system of male dogs experimentally infected with Toxoplasma gondii

O presente trabalho teve como objetivo descrever eventuais alterações histopatológicas no sistema reprodutor (testículo e epidídimo) de cães machos experimentalmente infectados com Toxoplasma gondii. Para tal, 10 animais sorologicamente negativos para T. gondii foram selecionados e distribuídos em três grupos experimentais: GI - três cães inoculados com 2,0 x 10(5) oocistos da cepa P, GII - três cães infectados com 1,0 x 10(6) taquizoítos da cepa RH e GIII - quatro cães mantidos como controle. Pesquisa de anticorpos (IFI) contra T. gondii foi realizada. A infecção por T. gondii confirmou-se pela soroconversão de todos os machos infectados a partir do 7° e do 14° dia pós-inoculação (DPI) para cães que receberam taquizoítos e oocistos respectivamente. Decorridos 70DPI, realizou-se, em todos os cães, orquiectomia, e amostras (testículo e epidídimo) foram coletadas e processadas histologicamente para leitura em microscópio óptico. As seguintes alterações foram diagnosticadas: infiltrado inflamatório mononuclear leve e moderado em epidídimo, edema celular moderado, degeneração hidrópica e fibrose intersticial moderada em túbulos seminíferos. Os resultados histopatológicos do presente trabalho, aliados ao isolamento do T. gondii em fragmentos de testículo e epidídimo pela imunoistoquímica, juntamente com os resultados encontrados na literatura por outros autores em diferentes tecidos, permitem inferir que as alterações encontradas nos cães infectados com o respectivo protozoário são sugestivas de infecção toxoplásmica.

Erythrocyte ghost cell-alkaline phosphatase: construction and characterization of a vesicular system for use in biomineralization studies

Alkaline phosphatase is required for the mineralization of bone and cartilage. This enzyme is localized in the matrix vesicle, which plays a role key in calcifying cartilage. In this paper we standardize a method to construction a resealed ghost cell-alkaline phosphatase system to mimic matrix vesicles and examine the kinetic behavior of the incorporated enzyme. Polidocanol-solubilized alkaline phosphatase, free of detergent, was incorporated into resealed ghost cells. This process was time-dependent and practically 50% of the enzyme was incorporated into the vesicles in 40 h of incubation, at 25 degreesC. Alkaline phosphatase-ghost cell systems were relatively homogeneous with diameters of about 300 nm and were more stable when stored at -20 degreesC.Alkaline phosphatase was completely released from the resealed ghost cell-system using only phospholipase C. These experiments confirm that the interaction between alkaline phosphatase and the lipid bilayer of resealed ghost cell is exclusively via glycosylphosphatidylinositol (GPI) anchor of the enzyme.An important point shown is that an enzyme bound to resealed ghost cell does not lose the ability to hydrolyze ATP, pyrophosphate and p-nitrophenyl phosphate (PNPP), but the presence of a ghost membrane, as a support of the enzyme, affects its kinetic properties. Moreover, calcium ions stimulate and phosphate ions inhibit the PNPPase activity of alkaline phosphatase present in resealed ghost cells. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Cardiovascular changes under normoxic and hypoxic conditions in the air-breathing teleost Synbranchus marmoratus: importance of the venous system

Synbranchus marmoratus is a facultative air-breathing fish, which uses its buccal cavity as well as its gills for air-breathing. S. marmoratus shows a very pronounced tachycardia when it surfaces to air-breathe. An elevation of heart rate decreases cardiac filling time and therefore may cause a decline in stroke volume (VS), but this can be compensated for by an increase in venous tone to maintain stroke volume. Thus, the study on S. marmoratus was undertaken to investigate how stroke volume and venous function are affected during air-breathing. To this end we measured cardiac output (Q), heart rate (fH), central venous blood pressure (PCV), mean circulatory filling pressure (MCFP), and dorsal aortic blood pressures (PDA) in S. marmoratus. Measurements were performed in aerated water (P-O2 > 130 mmHg), when the fish alternated between gill ventilation and prolonged periods of apnoeas, as well as during hypoxia (P-O2 <= 50 mmHg), when the fish changed from gill ventilation to air-breathing. Q increased significantly during gill ventilation compared to apnoea in aerated water through a significant increase in both fH and VS. PCV and MCFP also increased significantly. During hypoxia, when the animals surface to ventilate air, we found a marked rise in fH, PCV, MCFP, Q and VS, whereas PDA decreased significantly. Simultaneous increases in PCV and MCFP in aerated, as well as in hypoxic water, suggests that the venous system plays an important regulatory role for cardiac filling and VS in this species. In addition, we investigated adrenergic regulation of the venous system through bolus infusions of adrenergic agonists (adrenaline, phenylephrine and isoproterenol; 2 mu g kg(-1)). Adrenaline and phenylephrine caused a marked rise in PCV and MCFP, whereas isoproterenol led to a marked decrease in PCV, and tended to decrease MCFP. Thus, it is evident that stimulation of both alpha- and beta-adrenoreceptors affects venous tone in S. marmoratus.

The adrenergic regulation of the cardiovascular system in the South American rattlesnake, Crotalus durissus

The present study investigates adrenergic regulation of the systemic and pulmonary circulations of the anaesthetised South American rattlesnake, Crotalus durissus. Haemodynamic measurements were made following bolus injections of adrenaline and adrenergic antagonists administered through a systemic arterial catheter. Adrenaline caused a marked systemic vasoconstriction that was abolished by phentolamine, indicating this response was mediated through alpha-adrenergic receptors. Injection of phentolamine gave rise to a pronounced vasodilatation (systemic conductance (G(sys)) more than doubled), while injection of propranolol caused a systemic vasoconstriction, pointing to a potent alpha-adrenergic, and a weaker beta-adrenergic tone in the systemic vasculature of Crotalus. Overall, the pulmonary vasculature was far less responsive to adrenergic stimulation than the systemic circulation. Adrenaline caused a small but non-significant pulmonary vasodilatation and there was tendency of reducing this dilatation after either phentolamine or propranolol. Injection of phentolamine increased pulmonary conductance (G(pul)), while injection of propranolol produced a small pulmonary constriction, indicating that alpha-adrenergic and beta-adrenergic receptors contribute to a basal regulation of the pulmonary vasculature. Our results suggest adrenergic regulation of the systemic vasculature, rather than the pultrionary, may be an important factor in the development of intracardiac shunts. (c) 2007 Elsevier B.V. All rights reserved.

Global dynamics of the Rikitake system

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

GLOBAL DYNAMICS of THE LORENZ SYSTEM WITH INVARIANT ALGEBRAIC SURFACES

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

On the global dynamics of the Rabinovich system

In this paper by using the Poincare compactification in R(3) make a global analysis of the Rabinovich system(x) over dot = hy - v(1)x + yz, (y) over dot = hx - v(2)y - xz, (z) over dot = -v(3)z + xy,with (x, y, z) is an element of R(3) and ( h, v(1), v(2), v(3)) is an element of R(4). We give the complete description of its dynamics on the sphere at infinity. For ten sets of the parameter values the system has either first integrals or invariants. For these ten sets we provide the global phase portrait of the Rabinovich system in the Poincare ball (i.e. in the compactification of R(3) with the sphere S(2) of the infinity). We prove that for convenient values of the parameters the system has two families of singularly degenerate heteroclinic cycles. Then changing slightly the parameters we numerically found a four wings butterfly shaped strange attractor.

Physicochemical Characterization and Development of a Microemulsion System for Transdermal Use

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ecological efficiency and thermoeconomic analysis of a cogeneration system at a hospital

This work aims with an approach for cogeneration plants evaluation based on thermoeconomic functional diagram analysis. The second law of thermodynamics is used to develop a methodology to analyse cogeneration systems, based on exergoeconomics evaluation. The thermoeconomic optimisation method developed is applied to allow a better configuration of the cogeneration plant associated to a university hospital. Also ecological efficiency is evaluated. The method was efficient and contributes for thermoeconomics modelling and analysis and can be applied to any sort of thermal system, especially those with combined heat and power in thermal parity. (C) 2012 Elsevier Ltd. All rights reserved.

Electricity, hot water and cold water production from biomass. Energetic and economical analysis of the compact system of cogeneration run with woodgas from a small downdraft gasifier

Wood gasification technologies to convert the biomass into fuel gas stand out. on the other hand, producing electrical energy from stationary engine is widely spread, and its application in rural communities where the electrical network doesn't exist is very required. The recovery of exhaust gases (engine) is a possibility that makes the system attractive when compared with the same components used to obtain individual heat such as electric power. This paper presents an energetic alternative to adapt a fixed bed gasifier with a compact cogeneration system in order to cover electrical and thermal demands in a rural area and showing an energy solution for small social communities using renewable fuels. Therefore, an energetic and economical analysis from a cogeneration system producing electric energy, hot and cold water, using wooden gas as fuel from a small-sized gasifier was calculated. The energy balance that includes the energy efficiency (electric generation as well as hot and cold water system; performance coefficient and the heat exchanger, among other items), was calculated. Considering the annual interest rates and the amortization periods, the costs of production of electrical energy, hot and cold water were calculated, taking into account the investment, the operation and the maintenance cost of the equipments. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved.

Design of a control system using linear matrix inequalities for the active vibration control of a plate

The study of algorithms for active vibration control in smart structures is an area of interest, mainly due to the demand for better performance of mechanical systems, such as aircraft and aerospace structures. Smart structures, formed using actuators and sensors, can improve the dynamic performance with the application of several kinds of controllers. This article describes the application of a technique based on linear matrix inequalities (LMI) to design an active control system. The positioning of the actuators, the design of a robust state feedback controller and the design of an observer are all achieved using LMI. The following are considered in the controller design: limited actuator input, bounded output (energy) and robustness to parametric uncertainties. Active vibration control of a flat plate is chosen as an application example. The model is identified using experimental data by an eigensystem realization algorithm (ERA) and the placement of the two piezoelectric actuators and single sensor is determined using a finite element model (FEM) and an optimization procedure. A robust controller for active damping is designed using an LMI framework, and a reduced model with observation and control spillover effects is implemented using a computer. The simulation results demonstrate the efficacy of the approach, and show that the control system increases the damping in some of the modes.

Superconductors of the BPSCCO system obtained from rapid cooling process

Bi-based (BPSCCO) superconductors have been extensively studied due to their interesting superconducting properties, especially those that present high transition temperature (T-c). In this work, superconductors of the BPSCCO system were prepared from rapid cooling process and studied under its structural and magnetic properties. Sample as-prepared shows an amorphous behavior, which is converted progressively into 2223 phase. This process permits the control of Pb or Bi loss and the crystallization of the desired phase using several heat annealing processes. The 2201 and 2212 phases were also observed as intermediate phases, before the crystallization of the 2223 phase. The superconductor obtained in this work presented a T-c around 77-K. (C) 2005 Springer Science + Business Media, Inc.

Thermal treatment of superconductor thin film of the BSCCO system using domestic microwave oven

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

Scintigraphy of the hepatobiliar system in patients with pulmonary tuberculosis

The objective of this paper was to evaluate the hepatobiliary function of patients with pulmonary tuberculosis under triple treatment, using the technetium-99m-DISIDA (99mTc-DISIDA) hepatobiliary scintigraphy. Ten men and three women with pulmonary tuberculosis were subjected to hepatobiliary scintigraphy at the beginning of triple treatment (M1) and two months after it (M2). Patients were from the urban area, of low socioeconomic level, malnourished, and chronic alcohol and/or tobacco users. Ten normal individuals were evaluated as controls. Radiotracer images were acquired on a computerized gamma camera (Orbiter-Siemens) and T1/2 uptake and excretion values were calculated. Nutritional status and serum hepatic enzyme levels for each patient were evaluated at M1 and M2. None presented clinical or laboratory antecedent of hepatobiliary disease. At M1, there were no hepatic serum or kinetic alterations of the 99mTc-DISIDA. At M2, patients presented better nutritional conditions than at M1; there was increased serum aspartate aminotransferase (AST) and reduced excretion time for 99mTc-DISIDA, which was interpreted as a more adaptive than toxic phenomenon, yet not all alterations were significant and none manifested clinically. Apparently, triple treatment acted on the liver inducing the P450 cytochrome enzymatic system, accelerating radiotracer excretion, which follows the same path as the bilirubins.