Metabolic responses to glucoprivation induced by 2-deoxy-D-glucose in Brycon cephalus (Teleostei, Characidae)

The effects of functional cytoglucopenia provoked by 2-deoxy-D-glucose (2-DG) were studied in adult Brycon cephalus, an omnivorous fish from the Amazon Basin in Brazil. Glycogen content in liver and muscle as well as plasmatic glucose, free fatty acids (FFA), insulin, and glucagon were measured. After 48 h fasting, an intraperitoneal saline injection (NaCl 0.6 g/100 ml) was administered to control fish, whereas the experimental group received 2-DG, dissolved in saline, in the dosage of 80 mg/kg (0.487 mmol/kg) or 150 mg/kg (0.914 mmol/kg) body weight; injection volume was 5 ml in all treatments. Blood and tissue samples were taken immediately before, and 2, 8, 10, and 24 h after administration of the drug or saline. Fish injected with both doses of 2-DG showed a marked increase in glycemia levels. Liver and muscle glycogen decreased after 2-DG administration and reached their lowest values 10-24 h after injection, while in control animals no significant changes were observed. Elevation in plasma glucagon was observed only in response to the maximum dosage of 2-DG administered, especially 10 h and 24 h post-injection. Plasma insulin levels were lower in animals treated with the glucose analogue but only statistically significant 24 h after drug administration. In conclusion, the administration of the non-metabolizable glucose analogue 2-DG in B. cephalus is a stimulus to generate responses towards an increase in the glucose available to tissues, which is a characteristic of a fasting situation. All the above data support the interest of 2-DG administration as a model to study carbohydrate metabolism adjustment mechanisms in fish.

Estimativa do grau de infestação numa pastagem de Panicum maximum Jacq

Um piquete de capim-colonião (Panicum maximum Jacq) submetido a pastoreio contínuo e a roçadas periódicas revelou, seis anos após o plantio, elevado grau de infestação por outras plantas, destacando-se entre elas a grama-batatais (Paspalum notatum Flügge) que apresentou 85% de frequência e 20,9% de biomassa epígea seca relativa. As dicotiledóneas, em conjunto, apresentaram frequência de 95% e biomassa relativa de 38,7% mas a sua contribuição específica foi muito reduzida. O capim-colonião, por sua vez, apesar da frequência de 95%, apresentou apenas 32,2% de biomassa relativa (diminuição de 67,8%). Estas profundas alterações da flora e da vegetação podem ser atribuidas, em grande parte, a dois fatores: a) ação seletiva da roçadeira; b) preferências alimentares e disseminação endozoócora da gramabatatais pelos bovinos.

Effects of prolonged running performed at the intensity corresponding to the onset of blood lactate accumulation, on maximum isokinetic strength in active non-athletic individuals

OBJETIVO: O objetivo deste estudo foi analisar os efeitos da corrida contínua prolongada realizada na intensidade correspondente ao início do acúmulo do lactato no sangue (OBLA) sobre o torque máximo dos extensores do joelho analisado em diferentes tipos de contração e velocidade de movimento em indivíduos ativos. MÉTODO: Oito indivíduos do gênero masculino (23,4 ± 2,1 anos; 75,8 ± 8,7 kg; 171,1 ± 4,5 cm) participaram deste estudo. Primeiramente, os sujeitos realizaram um teste incremental até a exaustão voluntária para determinar a velocidade correspondente ao OBLA. Posteriormente, os sujeitos retornaram ao laboratório em duas ocasiões, separadas por pelo menos sete dias, para realizar 5 contrações isocinéticas máximas para os extensores do joelho em duas velocidades angulares (60 e 180º.s-1) sob as condições excêntrica (PTE) e concêntrica (PTC). Uma sessão foi realizada após um período de aquecimento padronizado (5 min a 50%VO2max). A outra sessão foi realizada após uma corrida contínua no OBLA até a exaustão voluntária. Essas sessões foram executadas em ordem randômica. RESULTADOS: Houve redução significante do PTC somente a 60º.s-1 (259,0 ± 46,4 e 244,0 ± 41,4 N.m). Entretanto, a redução do PTE foi significante a 60º.s-1 (337,3 ± 43,2 e 321,7 ± 60,0 N.m) e 180º.s-1 (346,1 ± 38,0 e 319,7 ± 43,6 N.m). As reduções relativas da força após o exercício de corrida foram significantemente diferentes entre os tipos de contração somente a 180º.s-1. CONCLUSÃO: Podemos concluir que, em indivíduos ativos, a redução no torque máximo após uma corrida contínua prolongada no OBLA pode ser dependente do tipo de contração e da velocidade angular.

Thermogenic capacity of three species of fruit-eating phyllostomid bats

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

Maximum entropy, fractal dimension and lacunarity in quantification of cellular rejection in myocardial biopsy of patients submitted to heart transplantation

This paper presents a method for the quantification of cellular rejection in endomyocardial biopsies of patients submitted to heart transplant. The model is based on automatic multilevel thresholding, which employs histogram quantification techniques, histogram slope percentage analysis and the calculation of maximum entropy. The structures were quantified with the aid of the multi-scale fractal dimension and lacunarity for the identification of behavior patterns in myocardial cellular rejection in order to determine the most adequate treatment for each case.

A Weak Maximum Principle for Optimal Control Problems with Nonsmooth Mixed Constraints

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Charge injection in an LED with a hybrid composite as the emissive layer

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

Flow-injection spectrophotometric determination of azithromycin in pharmaceutical formulations using p-chloranil in the presence of hydrogen peroxide

A flow-injection (FI) spectrophotometric procedure exploiting merging zones is proposed for the determination of azithromycin in pharmaceutical formulations. The method is based on the reaction of azithromycin with tetrachloro-phenzoquinone (p-chloranil) accelerated by hydrogen peroxide and conducted in a methanol medium, producing a purple-red color compound (lambda(max) = 540 nm). The FI system and the experimental conditions were optimized using a multivariate method. Beer's law is obeyed in a concentration range of 50 - 1600 mu g mL(-1) with an excellent correlation coefficient (r = 0.9998). The detection limit and the quantification limit were 6.6 and 22.1 mu g mL(-1), respectively. No interference was observed from the common excipients, and the recoveries were within 98.6 to 100.4%. The procedure was applied to the determination of azithromycin in pharmaceuticals with a high sampling rate (65 samples h(-1)). The results obtained by the proposed method were in good agreement with those obtained by the comparative method at 95% confidence level.

Simultaneous determination of Cu and Pb in fuel ethanol by graphite furnace AAS using tungsten permanent modifier with co-injection of Ir

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Flow injection analysis of paracetamol using a biomimetic sensor as a sensitive and selective amperometric detector

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

Direct determination of calcium in milk by atomic absorption spectrometry using flow-injection analysis

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

Sequential injection analysis system with spectrophotometric detection for determination of norfloxacin and ciprofloxacin in pharmaceutical formulations

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

Flow-injection spectrophotometric determination of tetracycline and doxycycline in pharmaceutical formulations using chloramine-T as oxidizing agent

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