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.

Genetic diversity and population structure of pumas (Puma concolor) in southeastern Brazil: implications for conservation in a human-dominated landscape

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

Activity, movement and secretive behavior of a threatened arboreal folivore, the thin-spined porcupine, in the Atlantic forest of southern Bahia, Brazil

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

Aggressive behavior in the genus Gallus sp

The intensification of the production system in the poultry industry and the vertical integration of the poultry agribusiness have brought profound changes in the physical and social environment of domestic fowls in comparison to their ancestors and have modified the expression of aggression and submission. The present review has covered the studies focusing on the different aspects linked to aggressiveness in the genus Gallus. The evaluated studies have shown that aggressiveness and subordination are complex behavioral expressions that involve genetic differences between breeds, strains and individuals, and differences in the cerebral development during growth, in the hormonal metabolism, in the rearing conditions of individuals, including feed restriction, density, housing type (litter or cage), influence of the opposite sex during the growth period, existence of hostile stimuli (pain and frustration), ability to recognize individuals and social learning. The utilization of fighting birds as experimental material in the study of mechanisms that have influence on the manifestation of aggressiveness in the genus Gallus might comparatively help to elucidate important biological aspects of such behavior.

The effect of pH on horseradish peroxidase-catalyzed oxidation of melatonin: production of N-1-acetyl-N-2-formyl-5-methoxykynuramine versus radical-mediated degradation

There is a g-rowing body of evidence that melatonin and its oxidation product, N-1-acetyl-N-2-formyl-5-methoxykynuramine (AFMK), have anti-inflammatory properties. From a nutritional point of view, the discovery of melatonin in plant tissues emphasizes the importance of its relationship with plant peroxidases. Here we found that the pH of the reaction mixture has a profound influence in the reaction rate and products distribution when melatonin is oxidized by the plant enzyme horseradish peroxidase. At pH 5.5. 1 mm of melatonin was almost completely oxidized within 2 min, whereas only about 3% was consumed at pH 7.4. However, the relative yield of AFMK was higher in physiological pH. Radical-mediated oxidation products, including 2-hydroxymelatonin a dimer of, 2-hydroxymelatonin and O-demethylated dimer of melatonin account for the fast consumption of melatonin at pH 5.5. The higher production of AFMK at pH 7.4 was explained by the involvement of compound III of peroxidases as evidenced by spectral studies. on the other hand, the fast oxidative degradation at pH 5.5 was explained by the classic peroxidase cycle.

Pessoas com deficiência no mercado de trabalho: considerações sobre políticas públicas nos Estados Unidos, União Europeia e Brasil

Atualmente, discussões a respeito da construção de uma sociedade inclusiva, ou seja, responsiva às diferenças, têm ocorrido em diversos países. de acordo com os princípios da inclusão social, a participação das pessoas com deficiência na sociedade depende de profundas transformações, cabendo à sociedade prover os suportes necessários para que esses indivíduos tenham acesso a todos os recursos disponíveis no meio social e, além disso, ao convívio de maneira não-segregada. Uma questão importante, nesse sentido, é a elaboração de políticas públicas no âmbito do trabalho voltadas para pessoas com deficiência. Embora o acesso ao trabalho seja considerado um dos principais direitos civis dos indivíduos, as pessoas com deficiência ainda encontram diversas barreiras para ingressar no mercado profissional. Partindo dessas afirmações, este artigo teve como objetivo discutir alguns dos principais aspectos das políticas de emprego adotadas nos Estados Unidos, na União Europeia e no Brasil para favorecer a inserção desses indivíduos no mercado de trabalho. Para tanto, três documentos legais, sendo um Nacional, um procedente dos Estados Unidos e outro, da União Europeia, foram analisados quanto aos itens: a) ano de publicação do documento; b) objetivos; c) definição de deficiência; e d) estratégias de inserção da pessoa com deficiência no mercado de trabalho. A partir das considerações realizadas, pode-se dizer que existem avanços e divergências nas políticas de emprego e que estas estão relacionadas às particularidades de cada um dos contextos; no entanto, existe uma preocupação comum em garantir à pessoa com deficiência o ingresso na atividade profissional.

Carbon fiber microelectrodes for adsorptive stripping analysis of trace nucleic acids

Carbon fiber ultramicroelectrodes are shown to be suitable for adsorptive stripping potentiometric measurements of trace DNA and RNA. The origin of the carbon fiber has a profound effect upon its suitability for trace analysis of nucleic acids, with the 'Aesar' materials performing most favorably. The resulting ultramicroelectrodes offer effective adsorptive accumulation of DNA and RNA from unstirred microliter-volume solutions, and are shown to be useful in adsorptive stripping transfer experiments. The influence of the surface pretreatment and accumulation conditions is described, along with the analytical-performance characteristics. The detection limits are 6, 15 and 40 mu g/l tRNA, ssDNA and dsDNA, respectively (5 min accumulation). (C) 1998 Elsevier B.V. S.A.

Black string corrections in variable tension braneworld scenarios

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Produtividade do milho safrinha e modificações químicas de um latossolo em sistema plantio direto em função de espécies de cobertura após calagem superficial

Modern agriculture is undergoing profound changes, with demands for more efficient management practices in the production systems used in each area. The objectives of this study were: to evaluate the effect of different covering species on a no-tillage system; to find the results of lime application on soil surface after sowing those forage species; measure the effects on soil chemical properties and subsequent effect on corn yield; and to determine the dry matter produced by each species used. The experiment was conducted on November, 2002, in the town of Palotina, Parana State, Brazil. A randomized block design was used, with 4 repetitions, in a 2x6 factorial scheme -two depths of soil sampling (0-10 and 10-20 cm) and six types of forage covering on the soil (Mucuna deeringiana, Crotalaria juncea, Setaria incana, Pennisetum glancum and Eleusine gracilis, as well as a mix of all these species). 3 t ha(-1) of dolomitic limestone were applied in total surface area, without amending. The covering species associated with the surface limestone application showed improvement in soil fertility, mainly in the layer of 10-20 cm, with prominence to Elensine gracilis, Crotalaria juncea and Setaria incana. Eleusine gracilis and Crotalaria juncea featured the largest dry matter production; however, the great amount of straw of Eleusine gracilis damaged the productivity of corn. Grain and corn straw productivity was higher when previously cultivated along with Setaria incana and the mix of forage species covering.

Prevenção de conflitos médico-legais no exercício da medicina

Os conflitos médico-legais que ocorrem no exercício da Cirurgia e da Medicina são motivos de preocupação não só no meio médico, mas também na sociedade como um todo, pois se de um lado geram um maior desgaste emocional ao médico, por outro, os pacientes estão sendo rejeitados. As causas desses conflitos são muitas, envolvendo fatores não assistenciais, como o sistema de saúde distorcido e desorganizado, a falta de participação da sociedade e do médico na melhoria desse sistema, o aparelho formador que lança no mercado grande número de jovens médicos despreparados para o exercício dessa nobre profissão, além da falta do ensino continuado. A solução para esses conflitos não poderá ser por meio de simples criação de leis, e nem pela negativa da existência do erro médico, que ocorre numa freqüência até maior do que os próprios conflitos. Todavia, pode-se afirmar que é muito importante melhorar a relação médico-paciente. É necessário, ainda, que o médico conheça a fundo seus deveres de conduta e que, principalmente, se abstenha de praticar abusos do poder. A sociedade deve também entender que a saúde não é uma questão exclusiva dos médicos e que deve lutar pela melhoria das condições dos níveis de vida.

Effect of soluble fiber on hypertriglyceridemia and immune profile in HIV-positive individuals undergoing highly active antiretroviral therapy

The advent of highly active antiretroviral therapy (HAART), since 1996, represented a profound impact on the natural history of HIV-infection by promoting important and sustainable viral replication suppression and increasing survival and quality of life among seropositive patients. Nonetheless, antiretroviral therapy has been observed to be accompanied by metabolic alterations such as dyslipidemia, especially hypertriglyceridemia, insulin resistance, hyperglycemia and lipodystrophy (body fat redistribution). Epidemiological studies have demonstrated a correlation between high triglyceride (TG) levels and higher incidence of coronary artery disease (CAD). Some investigators suggest dietary intervention as part of hyperlipidemia treatment, including an increase in soluble fiber intake (10-25g/day). Whereas some studies have demonstrated that both cholesterol and serum triglyceride levels decrease with the use of food fiber, others have shown just a serum triglyceride decrease, and others failed to observe any alteration in lipid metabolism. The purpose of this study was to assess the effect of soluble fiber (R) (partially hydrolyzed guar gum) supplementation on hypertriglyceridemia and immune profile in HIVpositive individuals on HAART. Nineteen HIV-positive individuals with hypertriglyceridemia (serum levels >= 150 to < 500mg/dl) were studied. of these individuals, 63.16% were males and 36.84% females, with mean age of 43.52 +/- 9.22 years. These individuals had been on the same HAART regimen for at least six months, had no change in therapy during the study and received 20g/day of soluble fiber for four months at pre-established times. Clinical-nutritional, biochemical (total proteins, albumin, globulin, total cholesterol, LDL-c, HDL-c, TG, TG/HDL-c and LDLc/HDL-c), hematimetric (hemoglobin, hematocrit and total lymphocytes), and immunologic (lymphocytes T CD4(+), T CD8(+); T CD4(+)/CD8(+) ratio, viral load, TNF-alpha and IL-6) parameters were assessed in all patients at three time points (M0: pretreatment, M1: 30 days, and M2: four months after intervention). Significance level was set at 5% for all data statistically analyzed. Serum TG and TG/HDL-c ratio reduction was observed at all time points, but statistical significance was found just at M0 and M2. The remaining biochemical, hematimetric and immunologic parameters (lymphocytes T CD4(+), T CD8(+); T CD4(+)/ CD8(+) ratio, and viral load) showed no significant difference at all times. Regarding serum cytokines, TNF-alpha and IL-6 significantly decreased between M0 and M2, and only IL-6 reduced between M1 and M2. The data collected show that dietary and anthropometric parameters remained unchanged excluding potential confounding factors related with the effect of fiber supplementation on serum TG, TNF-alpha and IL-6. Thus, soluble fiber (R) contributed to an important reduction in hypertriglyceridemia and in the serum levels of the proinflammatory cytokines TNF-alpha and IL-6 in HIV-seropositive individuals on HAART. In addition, soluble fiber (R) might have minimized the process of atherosclerosis in these individuals, given that elevated serum levels of TG, TNF-alpha and IL-6 have been associated with the development of these lesions.

Food-dependent, exercise-induced gastrointestinal distress

Among athletes strenuous exercise, dehydration and gastric emptying (GE) delay are the main causes of gastrointestinal (GI) complaints, whereas gut ischemia is the main cause of their nausea, vomiting, abdominal pain and (blood) diarrhea. Additionally any factor that limits sweat evaporation, such as a hot and humid environment and/or body dehydration, has profound effects on muscle glycogen depletion and risk for heat illness. A serious underperfusion of the gut often leads to mucosal damage and enhanced permeability so as to hide blood loss, microbiota invasion (or endotoxemia) and food-born allergen absorption (with anaphylaxis). The goal of exercise rehydration is to intake more fluid orally than what is being lost in sweat. Sports drinks provide the addition of sodium and carbohydrates to assist with intestinal absorption of water and muscle-glycogen replenishment, respectively. However GE is proportionally slowed by carbohydrate-rich (hyperosmolar) solutions. on the other hand, in order to prevent hyponatremia, avoiding overhydration is recommended. Caregiver's responsibility would be to inform athletes about potential dangers of drinking too much water and also advise them to refrain from using hypertonic fluid replacements.

Hypertrophy and neuron loss: structural changes in sheep SCG induced by unilateral sympathectomy

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

Crystal structure of human purine nucleoside phosphorylase complexed with acyclovir

In human, purine nucleoside phosphorylase (HsPNP) is responsible for degradation of deoxyguanosine and genetic deficiency of this enzyme leads to profound T-cell mediated immunosuppression. PNP is therefore a target for inhibitor development aiming at T-cell immune response modulation and has been submitted to extensive structure-based drug design. This work reports the first crystallographic Study of human PNP complexed with acyclovir (HsPNP:Acy). Acyclovir is a potent clinically useful inhibitor of replicant herpes simplex virus that also inhibits human PNP but with a relatively lower inhibitory activity (K-i=90muM). Analysis of the structural differences among the HsPNP:Acy complex, PNP apoenzyme, and HsPNP:Immucillin-H provides explanation for inhibitor binding, refines the purine-binding site, and can be used for future inhibitor design. (C) 2003 Published by Elsevier B.V.

Crystal structure of human purine nucleoside phosphorylase at 2.3 angstrom resolution

Purine nucleoside phosphorylase (PNP) catalyzes the phosphorolysis of the N-ribosidic bonds of purine nucleosides and deoxynucleosides. In human, PNP is the only route for degradation of deoxyguanosine and genetic deficiency of this enzyme leads to profound T-cell mediated immunosuppression. PNP is therefore a target for inhibitor development aiming at T-cell immune response modulation and its low resolution structure has been used for drug design. Here we report the structure of human PNP solved to 2.3 Angstrom resolution using synchrotron radiation and cryocrystallographic techniques. This structure allowed a more precise analysis of the active site, generating a more reliable model for substrate binding. The higher resolution data allowed the identification of water molecules in the active site, which suggests binding partners for potential ligands. Furthermore, the present structure may be used in the new structure-based design of PNP inhibitors. (C) 2003 Published by Elsevier B.V.