In vitro basal cytotoxicity assay applied to estimate acute oral systemic toxicity of grandisin and its major metabolite

Preclinical investigations can start with preliminary in vitro studies before using animal models. Following this approach, the number of animals used in preclinical acute toxicity testing can be reduced. In this study, we employed an in-house validated in vitro cytotoxicity test based on the Spielmann approach for toxicity evaluation of the lignan grandisin, a candidate anticancer agent, and its major metabolite. the 4-O-demethylgrandisin, by neutral red uptake (NRU) assay, on mouse fibroblasts Balb/c 3T3 cell line. Using different concentrations of grandisin and its major metabolite (2.31; 1.16; 0.58; 0.29; 0.14; 0.07; 0.04; 0.002 mu M) in Balb/c 3T3-A31 NRU cytotoxicity assay, after incubation for 48 h, we obtained IC(50) values for grandisin and its metabolite of 0.078 and 0.043 mu M, respectively. The computed LD(50) of grandisin and 4-O-demethylgrandisin were 617.72 and 429.95 mg/kg, respectively. Both were classified under the Globally Harmonized System as category 4. Since pharmacological and toxicological data are crucial in the developmental stages of drug discovery, using an in vitro assay we demonstrated that grandisin and its metabolite exhibit distinct toxicity profiles. Furthermore, results presented in this work can contribute to reduce the number of animals required in subsequent pharmacological/toxicological studies. (C) 2010 Elsevier GmbH. All rights reserved.

Lateralização cerebral de funções e sua implicação para a cognição humana: do paradigma do duplo sistema funcional de processamento a um enfoque de sistema complexo

Este trabalho examina a lateralização cerebral de funções e sua implicação para a cognição humana ao nível da intersecção entre a neuropsicologia clinica e a psicologia cognitiva de base informacional. A primeira parte do trabalho e dedicada a descrição e análise critica da conformação contemporânea desta área de investigação neuropsicológica, com a ênfase posta na metateoria e teorias predominantes, a par do sistema conceitual utilizado nas atividades de pesquisa desenvolvidas na área. Inicialmente, a abordagem neuropsicológica do problema da lateralização cerebral examinada no que concerne às suas articulações com os métodos e técnicas que se mostraram mais importantes para a configuração atual desta área de investigação, sob um enfoque histórico. Em continuidade, a análise dirigida às questões mais fundamentais nas quais se tem desdobrado o problema da assimetria funcional inter-hemisférica, representadas pelas especializações funcionais dos hemisférios cerebrais, pela atividade conjunta dos hemisférios e pelas relações entre diferenças individuais na lateralização cerebral e desempenho cognitivo. Neste contexto são sublinhadas as dificuldades e inconsistências relacionadas à restritividade do enfoque prevalente, avaliado como expressão de uma concepção neuropsicológica excessivamente simplificadora do problema compreendido pelas relações entre o cérebro e a cognição humanos. O trabalho apresenta, em sua segunda parte, uma tentativa de desenvolvimento de um enfoque sistêmico, na direção da complexidade, para o problema da lateralização cerebral de funções. Trata-se de um desenvolvimento que parte de uma descentração da dimensão lateral do sistema nervoso e resulta em uma subsunção deste problema à uma perspectiva mais global concernente à organização cerebral de funções e aos fundamentos para a construção teórica na neuropsicologia. Segue-se um exame das implicações deste enfoque para a questão das relações entre variações inter-individuais na lateralização cerebral de funções e habilidades cognitivas que se direciona para uma minimização do significado que tem sido atribuído a lateralizarão para o funcionamento cerebral e a cognição humanos. O trabalho apresenta, finalmente, um estudo empírico referente às relações entre variações inter-individuais normais de lateralizarão cerebral ,preferência manipulatória e sua história familiar e desempenho cognitivo, onde são comparados os desempenhos de destros com história familiar de sinistralidade negativa e de canhotos com esta história positiva no Teste WAIS. Os resultados obtidos mostram uma inequívoca semelhança nos desempenhos dos dois grupos em todas as escalas do WAIS. Estes resultados são discutidos principalmente no que tange à existência ou não de correspondências diretas entre variações normais nas representações das funções ao longo da dimensão lateral do sistema nervoso, preferência manipulatória e habilidades cognitivas. A conclusão final conforma-se como um sumário integrativo dos principais aspectos das conclusões atingidas no curso do trabalho.

We're Chained: an analysis of systemic risk in finance

This dissertation presents two papers on how to deal with simple systemic risk measures to assess portfolio risk characteristics. The first paper deals with the Granger-causation of systemic risk indicators based in correlation matrices in stock returns. Special focus is devoted to the Eigenvalue Entropy as some previous literature indicated strong re- sults, but not considering different macroeconomic scenarios; the Index Cohesion Force and the Absorption Ratio are also considered. Considering the S&P500, there is not ev- idence of Granger-causation from Eigenvalue Entropies and the Index Cohesion Force. The Absorption Ratio Granger-caused both the S&P500 and the VIX index, being the only simple measure that passed this test. The second paper develops this measure to capture the regimes underlying the American stock market. New indicators are built using filtering and random matrix theory. The returns of the S&P500 is modelled as a mixture of normal distributions. The activation of each normal distribution is governed by a Markov chain with the transition probabilities being a function of the indicators. The model shows that using a Herfindahl-Hirschman Index of the normalized eigenval- ues exhibits best fit to the returns from 1998-2013.

Thiamethoxam on the histological characteristics of sugarcane young roots

Thiamethoxam is a systemic insecticide from the neonicotinoid group, nitroguanidin family which affects the nicotinic receptor acetyl choline in the insect membrane, wounding the nervous system and causing the death of the insect. It was used with success in the control of initial pests of several crops. It was considered that thiamethoxam has a bioactivator effect, because in the absence of insects promoted increase in vigor, development and productivity of crops. This work was carried out to verify if thiamethoxam causes histological changes in sugarcane roots. In this work, it was used optical microscopy, images arrest, tissue biometrics and statistical analysis, in young roots of sugarcane RB 83 5486 after the treatments with different thiamethoxam concentrations. It was determined changes in histological structure of tissues 7, 14, 21 and 28 days after the treatments, establishing its effects on root plant anatomy. It was verified that thiamethoxam increased root cortex width, increasing the vascular cylinder and the metaxylem vessel elements number in the vascular tissue until 21 days after application.

Generalized systemic cryptococcosis in a dog after immunosuppressive corticotherapy

Um cão da raça Boxer, macho, com 2 anos e 11 meses de idade foi encaminhado ao hospital veterinário com histórico de distúrbio gastroentérico de dois meses de duração, apatia, hiporexia, emagrecimento progressivo e deficiência visual. Ataxia e vocalização foram observadas posteriormente. O animal estava sendo tratado em outra clínica veterinária com antibióticos e doses imunossupressoras de corticóides, direcionados ao controle de provável enterite alimentar. A morte ocorreu após cinco dias. As observações macro e microscópica revelaram tratar-se de criptococose sistêmica, atingindo trato digestório, olhos, SNC, rins, pâncreas e linfonodos. O presente relato enfatiza a infecção fúngica criptocócica quanto aos seus aspectos grastrointestinais iniciais a serem considerados no diagnóstico clínico, ressaltando a imunossupressão induzida pela corticoterapia.

Systemic inflammatory response indicators in rabbits (Oryctolagus cuniculus) experimentally infected with sporulated oocysts of Eimeria stiedai (Apicomplexa: Eimeriidae)

Hemograms and acute-phase proteins in adult male New Zealand White rabbits that had been experimentally infected orally with sporulated oocysts of Eimeria stiedai were evaluated over a 28-day period. Fifty animals were used, divided into two groups: group A infected with 1 x 10(4) sporulated oocysts of E. stiedai and group B inoculated with distilled water. on the seventh day after infection, the infected animals presented anemia and leukocytosis with neutrophilia and monocytosis. Protein fractionation by means of electrophoresis identified 19 acute-phase proteins with molecular weights ranging from 24 to 238 kD. Ceruloplasmin, transferrin and haptoglobin showed high levels on the seventh day after infection, with gradual increases in their concentrations until the end of the experimental period. Thus, from the data of the present study, E. stiedai is considered to be a pyogenic etiological agent for which the infection level can be monitored through the leukocyte count and serum concentrations of ceruloplasmin, transferrin and haptoglobin, and these can be recommended as complementary tests.

Systemic and local antibodies induced by an experimental inactivated vaccine against bovine herpesvirus type 1

Uma vacina experimental inativada contra o herpesvírus bovino tipo 1 (BoHV-1) foi produzida com o objetivo de se avaliar a resposta imune humoral local e sistêmica contra o BoHV-1, em 12 novilhas soronegativas, após a vacinação e a revacinação. Os soros foram submetidos à prova de vírus-neutralização para quantificação do título de anticorpos neutralizantes e a um ELISA para detecção de IgG1 e IgG2. Os swabs nasais também foram submetidos ao ELISA para detecção de IgG1 e IgG2 na secreção nasal. Os resultados demonstraram que títulos de anticorpos neutralizantes foram induzidos após a revacinação, em níveis moderados a altos, permanecendo em níveis significativos no soro sanguíneo e na secreção nasal até o dia 114 pós-vacinação. O IgG2 foi o isótipo predominante na maior parte do período pós-vacinação, tanto na secreção nasal, como no compartimento sistêmico. A vacina experimental inativada contra o BoHV-1 estimulou níveis de anticorpos potencialmente protetores dos isótipos IgG1 e IgG2, tanto no compartimento sistêmico, como nas mucosas.

The autonomic control and functional significance of the changes in heart rate associated with air breathing in the jeju, Hoplerythrinus unitaeniatus

The jeju is a teleost fish with bimodal respiration that utilizes a modified swim bladder as an air-breathing organ (ABO). Like all air-breathing fish studied to date, jeju exhibit pronounced changes in heart rate (f(H)) during air-breathing events, and it is believed that these may facilitate oxygen uptake (M-O2) from the ABO. The current study employed power spectral analysis (PSA) of f(H) patterns, coupled with instantaneous respirometry, to investigate the autonomic control of these phenomena and their functional significance for the efficacy of air breathing. The jeju obtained less than 5% of total M-O2 (M-tO2) from air breathing in normoxia at 26 degrees C, and PSA of beat-to-beat variability in fH revealed a pattern similar to that of unimodal water-breathing fish. In deep aquatic hypoxia (water P-O2=1 kPa) the jeju increased the frequency of air breathing (f(AB)) tenfold and maintained M-tO2 unchanged from normoxia. This was associated with a significant increase in heart rate variability (HRV), each air breath (AB) being preceded by a brief bradycardia and then followed by a brief tachycardia. These f(H) changes are qualitatively similar to those associated with breathing in unimodal air-breathing vertebrates. Within 20 heartbeats after the AB, however, a beat-to-beat variability in f(H) typical of water-breathing fish was re-established. Pharmacological blockade revealed that both adrenergic and cholinergic tone increased simultaneously prior to each AB, and then decreased after it. However, modulation of inhibitory cholinergic tone was responsible for the major proportion of HRV, including the precise beat-to-beat modulation of f(H) around each AB. Pharmacological blockade of all variations in f(H) associated with air breathing in deep hypoxia did not, however, have a significant effect upon f(AB) or the regulation of M-tO2. Thus, the functional significance of the profound HRV during air breathing remains a mystery.

The role of nitric oxide in the regulation of the systemic and pulmonary vasculature of the rattlesnake, Crotalus durissus terrificus

The functional role of nitric oxide (NO) was investigated in the systemic and pulmonary circulations of the South American rattlesnake, Crotalus durissus terrificus. Bolus, intra-arterial injections of the NO donor, sodium nitroprusside (SNP) caused a significant systemic vasodilatation resulting in a reduction in systemic resistance (Rsys). This response was accompanied by a significant decrease in systemic pressure and a rise in systemic blood flow. Pulmonary resistance (Rpul) remained constant while pulmonary pressure (Ppul) and pulmonary blood flow (Qpul) decreased. Injection of L-Arginine (L-Arg) produced a similar response to SNP in the systemic circulation, inducing an immediate systemic vasodilatation, while Rpul was unaffected. Blockade of NO synthesis via the nitric oxide synthase inhibitor, L-NAME, did not affect haemodynamic variables in the systemic circulation, indicating a small contribution of NO to the basal regulation of systemic vascular resistance. Similarly, Rpul and Qpul remained unchanged, although there was a significant rise in Ppul. Via injection of SNP, this study clearly demonstrates that NO causes a systemic vasodilatation in the rattlesnake, indicating that NO may contribute in the regulation of systemic vascular resistance. In contrast, the pulmonary vasculature seems far less responsive to NO.

Molecular mapping of the viral determinants of systemic wilting induced by a Lettuce mosaic virus (LMV) isolate in some lettuce cultivars

The isolate AF199 of Lettuce mosaic virus (LMV, genus Potyvirus) causes local lesions followed by systemic wilting and plant death in the lettuce cultivars Ithaca and Vanguard 75. Analysis of the phenotype of virus chimeras revealed that a region within the PI protein coding region (nucleotides 112-386 in the viral genome) and/or another one within the CI protein coding region (nucleoticles 5496-5855) are sufficient together to cause the lethal wilting in Ithaca, but not in Vanguard 75. This indicates that the determinants of this particular symptom are different in these two lettuce cultivars. The wilting phenotype was not directly correlated with differences in the deduced amino acid sequence of these two regions. Furthermore, transient expression of the LMV-AF 199 proteins, separately or in combination, did not induce local necrosis or any other visible reaction in the plants. Together, these results Suggest that the systemic wilting reaction might be Clue to RNA rather than protein sequences. (c) 2004 Elsevier B.V. All rights reserved.

Fractal correlation of heart rate variability in obese children

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

Anxiety-induced antinociception in mice: effects of systemic and intra-amygdala administration of 8-OH-DPAT and midazolam

Rationale: Mice exhibit antinociception after a single experience in the elevated plus maze (EPM), an animal model of anxiety. Objective: This study investigated the mechanisms involved in this form of anxiety-induced antinociception. Methods: Nociception was evaluated by means of the writhing test in mice confined either to the open or enclosed arms of the EPM. The effects of systemic (naloxone, midazolam and 8-OH-DPAT) or intra-amygdala (8-OH-DPAT. NAN-190 and midazolam) drug infusions were investigated in mice previously treated i.p. with 0.6% acetic acid, an algic stimulus that induces abdominal contortions. The effects of these drugs on conventional measures of anxiety (% entries and % time in open arms) in a standard EPM test were also independently investigated. Results: Open-arm confinement resulted in a high-magnitude antinociception (minimum 85%, maximum 450%) compared with enclosed arm confinement. The opiate antagonist naloxone (1 mg/kg and 10 mg/kg) neither blocked this open arm-induced antinociception (OAIA) nor modified indices of anxiety in EPM. Administration of midazolam (0.5-2 mg/kg, s.c.) increased OAIA and produced antinociception in enclosed confined animals, as well as attenuating anxiety in the EPM. The 5-HT(1A) receptor agonist 8-OH-DPAT (0.05-1 mg/kg, s.c.) had biphasic effects on OAIA, antagonising the response at the lowest dose and intensifying it at the highest dose. In addition, low doses of this agent reduced anxiety in the EPM. Although bilateral injections of 8-OH-DPAT (5.6 nmol/0.4 mu l) or NAN-190 (5.6 nmol and 10 nmol/0.4 mu l) into the amygdala did not alter OAIA, increased anxiety was observed in the EPM. In contrast, intra-amygdala administration of midazolam (10 nmol and 30 nmol/0.4 mu l) blocked both OAIA and anxiety. Conclusions: These results with systemic and intracerebral drug infusion suggest that 5-HT(1A) receptors localised in the amygdala are not involved in the pain inhibitory processes that are recruited during aversive situations. However, activation of these receptors does phasically increase anxiety. Although the intrinsic antinociceptive properties of systemically administered midazolam confounded interpretation of its effects on OAIA, intra-amygdala injections of this compound suggest that benzodiazepine receptors in this brain region modulate both the antinociceptive and behavioural (anxiety) responses to the EPM.

Influence of Th1/Th2 cytokines and nitric oxide in murine systemic infection induced by Sporothrix schenckii

In an attempt to elucidate the effects of Sporothrix schenckii infection on the immune response, our laboratory has developed a murine model of disseminated sporotrichosis. Helper T cells can be further subdivided into Th1 and Th2 phenotypes. The differentiation of two subsets of T lymphocytes is driven by IL-12 and IL-4 cytokines, respectively. Th1 cells produce IFN-gamma that activate macrophages and promote cell-mediated immunity. In addition, we found low levels of iNOS and NO production in the initial (1st and 2nd weeks) and final (9th and 10th weeks) periods of the infection, in contrast with the period of week 4 to 7 of elevated values. The determination of IFN-gamma and IL-12 are in agreement with NO/iNOS detection, showing the presence of cellular immune response throughout the infectious process. However, the production of IL-4 shows an increase in levels after the 5th and 6th weeks suggesting a participation of Th2 response in this period as well. Regarding these results, the study demonstrated that in experimental sporotrichosis infection the cellular immune response participated throughout the period analyzed as a nitric oxide dependent mechanism. In contrast, the presence of Th2 response began in the 5th week, suggesting the participation of humoral immune response in advanced stages of sporotrichosis.