Resistance of Aedes aegypti to temephos and adaptive disadvantages

OBJECTIVE To evaluate the resistance of Aedes aegypti to temephos Fersol 1G (temephos 1% w/w) associated with the adaptive disadvantage of insect populations in the absence of selection pressure. METHODS A diagnostic dose of 0.28 mg a.i./L and doses between 0.28 mg a.i./L and 1.40 mg a.i./L were used. Vector populations collected between 2007 and 2008 in the city of Campina Grande, state of Paraíba, were evaluated. To evaluate competition in the absence of selection pressure, insect populations with initial frequencies of 20.0%, 40.0%, 60.0%, and 80.0% resistant individuals were produced and subjected to the diagnostic dose for two months. Evaluation of the development of aquatic and adult stages allowed comparison of the life cycles in susceptible and resistant populations and construction of fertility life tables. RESULTS No mortality was observed in Ae. aegypti populations subjected to the diagnostic dose of 0.28 mg a.i./L. The decreased mortality observed in populations containing 20.0%, 40.0%, 60.0%, and 80.0% resistant insects indicates that temephos resistance is unstable in the absence of selection pressure. A comparison of the life cycles indicated differences in the duration and viability of the larval phase, but no differences were observed in embryo development, sex ratio, adult longevity, and number of eggs per female. CONCLUSIONS The fertility life table results indicated that some populations had reproductive disadvantages compared with the susceptible population in the absence of selection pressure, indicating the presence of a fitness cost in populations resistant to temephos.

Population biology of Eudendrium caraiuru (Cnidaria, Anthoathecata, Eudendriidae) from São Sebastião Channel, Southeastern Brazil

The ecology of Eudendrium spp. from the Brazilian coast is poorly known, although it already proved to be useful and important as a tool to solve some taxonomical problems of the genus. The seasonality and reproduction patterns of a population of Eudendrium caraiuru Marques & Oliveira, 2003 were studied. Data were sampled from test panels immersed in the water off Cabelo Gordo de Dentro beach, in São Sebastião Channel, Southeastern Brazil, from July 1999 to July 2000, every three months. Eudendrium caraiuru was active throughout the study period. Reproductive peaks of the species were regulated by cold and low-salinity water, although part of the population always bore mature gonophores. In addition to morphological differences, ecological differences between E. caraiuru and its similar species, E. glomeratum Picard, 1951, especially from well known populations of the Mediterranean Sea, corroborated that these species are diverse lineages of a unique ancestor.

Space-time variation of the relative abundance of Limnoperna fortunei in deep zones of São Gonçalo Channel, Rio Grande do Sul, Brazil

This work describes the spatial-temporal variation of the relative abundance and size of Limnoperna fortunei (Dunker, 1857) collected in São Gonçalo Channel through bottom trawl with a 0.5 cm mesh, at depths between 3 and 6 m. The estimative of mean relative abundance (CPUE) ranged from 2,425.3 individuals per drag (ind./drag) in the spring to 21,715.0 ind./drag in the fall, with an average of 9,515.3 ind./drag throughout the year. The estimated mean density of L. fortunei for the deep region of São Gonçalo Channel ranged from 1.2 to 10.3 ind./m², and it was recorded a maximum density of 84.9 ind./m² in the fall of 2008. The method of sampling using bottom trawl enabled the capture of L. fortunei under the soft muddy bottom of the channel, in different sizes ranging from 0.4 to 3.2 cm. This shows that the structure of the L. fortunei adult population under the bottom of the São Gonçalo Channel is composed mostly of small individuals (<1.4 cm), which represent up to 74% of the population collected.

Investigation into in vitro anti-leishmanial combinations of calcium channel blockers and current anti-leishmanial drugs

The need for drug combinations to treat visceral leishmaniasis (VL) arose because of resistance to antimonials, the toxicity of current treatments and the length of the course of therapy. Calcium channel blockers (CCBs) have shown anti-leishmanial activity; therefore their use in combination with standard drugs could provide new alternatives for the treatment of VL. In this work, in vitro isobolograms of Leishmania (Leishmania) chagasi using promastigotes or intracellular amastigotes were utilised to identify the interactions between five CCBs and the standard drugs pentamidine, amphotericin B and glucantime. The drug interactions were assessed with a fixed ratio isobologram method and the fractional inhibitory concentrations (FICs), sum of FICs (ΣFICs) and the overall mean ΣFIC were calculated for each combination. Graphical isobologram analysis showed that the combination of nimodipine and glucantime was the most promising in amastigotes with an overall mean ΣFIC value of 0.79. Interactions between CCBs and the anti-leishmanial drugs were classified as indifferent according to the overall mean ΣFIC and the isobologram graphic analysis.

Antischistosomal activity of a calcium channel antagonist on schistosomula and adult Schistosoma mansoni worms

Current schistosomiasis control strategies are largely based on chemotherapeutic agents and a limited number of drugs are available today. Praziquantel (PZQ) is the only drug currently used in schistosomiasis control programs. Unfortunately, this drug shows poor efficacy in patients during the earliest infection phases. The effects of PZQ appear to operate on the voltage-operated Ca2+channels, which are located on the external Schistosoma mansoni membrane. Because some Ca2+channels have dihydropyridine drug class (a class that includes nifedipine) sensitivity, an in vitro analysis using a calcium channel antagonist (clinically used for cardiovascular hypertension) was performed to determine the antischistosomal effects of nifedipine on schistosomula and adult worm cultures. Nifedipine demonstrated antischistosomal activity against schistosomula and significantly reduced viability at all of the concentrations used alone or in combination with PZQ. In contrast, PZQ did not show significant efficacy when used alone. Adult worms were also affected by nifedipine after a 24 h incubation and exhibited impaired motility, several lesions on the tegument and intense contractility. These data support the idea of Ca2+channels subunits as drug targets and favour alternative therapeutic schemes when drug resistance has been reported. In this paper, strong arguments encouraging drug research are presented, with a focus on exploring schistosomal Ca2+channels.

Whole-body MRI: comprehensive evaluation on a 48-channel 3T MRI system in less than 40 minutes. Preliminary results

OBJECTIVE: To evaluate a comprehensive MRI protocol that investigates for cancer, vascular disease, and degenerative/inflammatory disease from the head to the pelvis in less than 40 minutes on a new generation 48-channel 3T system. MATERIALS AND METHODS: All MR studies were performed on a 48-channel 3T MR scanner. A 20-channel head/neck coil, two 18-channel body arrays, and a 32-channel spine array were employed. A total of 4 healthy individuals were studied. The designed protocol included a combination of single-shot T2-weighted sequences, T1-weighted 3D gradient-echo pre- and post-gadolinium. All images were retrospectively evaluated by two radiologists independently for overall image quality. RESULTS: The image quality for cancer was rated as excellent in the liver, pancreas, kidneys, lungs, pelvic organs, and brain, and rated as fair in the colon and breast. For vascular diseases ratings were excellent in the aorta, major branch vessel origins, inferior vena cava, portal and hepatic veins, rated as good in pulmonary arteries, and as poor in the coronary arteries. For degenerative/inflammatory diseases ratings were excellent in the brain, liver and pancreas. The inter-observer agreement was excellent. CONCLUSION: A comprehensive and time efficient screening for important categories of disease processes may be achieved with high quality imaging in a new generation 48-channel 3T system.

Análise interactômica da VDAC (voltage-dependent anion selective channel) nos cérebros aviar, bovino e murino

A VDAC é a proteína mais abundante na membrana mitocondrial externa. Exerce o controle da atividade desta organela através da regulação da troca de metabólitos e tem função crucial no mecanismo de apoptose. Em nosso caso, os estudos dos complexos protéicos, das interações entre a VDAC e outras proteínas presentes no interior do neurônio que auxiliam na manutenção das funções das organelas e da célula, fazem parte da chamada interactômica. O presente estudo determinou o interactoma do complexo protéico Hexoquinase-VDAC-ANT presente em cérebros murino, bovino e aviar. Nosso objetivo foi identificar se as expressões diferenciadas da VDAC1 e VDAC2 verificadas nos cérebros murino, aviar e bovino, estão associadas a diferenças nos interactomas dessas proteínas. Este estudo revelou que as espécies aviar e bovina apresentaram o maior número de complexos protéicos contendo VDACs (5) quando comparadas com os neurônios de rato (1), o que é indicativo de uma cinética diferencial de montagem ou desmontagem do complexo. Além disso, a VDAC mitocondrial neuronal aviar também interage com mais proteínas em relação à VDAC mitocondrial neuronal bovina, o que é resultado de uma composição de subunidades diferenciada. Tais resultados indicam diferenças significativas quanto ao metabolismo energético e apoptótico no cérebro aviar, bovino e murino, existindo interações diferenciais da VDAC no cérebro aviar.

An Hp-Adaptive Hierarchical Formulation for the Boundary Element Method Applied to Elasticity in Two Dimensions

This paper presents an HP-Adaptive Procedure with Hierarchical formulation for the Boundary Element Method in 2-D Elasticity problems. Firstly, H, P and HP formulations are defined. Then, the hierarchical concept, which allows a substantial reduction in the dimension of equation system, is introduced. The error estimator used is based on the residual computation over each node inside an element. Finally, the HP strategy is defined and applied to two examples.

Adaptive value of ryegrass biotypes with low-level resistance and susceptible to the herbicide fluazifop and competitive ability with the wheat culture

Ryegrass is the main weed in wheat crop, causing yield loss due to competition by environmental resources. The objectives of this study were to estimate the fitness cost of ryegrass biotypes with low-level resistance and susceptible to fluazifop and to investigate the relative competitive ability of these biotypes between themselves and against the crop. Thus, fitness cost and competitive ability experiments were conducted under greenhouse conditions. For the fitness cost experiments, the low-level resistant ryegrass biotypes and those susceptible to fluazifop were used. For competitive ability, the treatments were arranged in a replacement series, with five proportions of the wheat cultivar FUNDACEP Horizonte and the low-level resistant and susceptible ryegrass biotypes 100:0, 75:25, 50:50, 25:75 and 0:100. Competitive analysis was carried out through diagrams applied to the replacement experiments and use of relative competitiveness indices. Variables evaluated were plant height, in the fitness cost experiment, and leaf area and shoot dry biomass in both experiments. The ryegrass biotypes show overall similar fitness cost and competitive ability. The wheat cultivar FUNDACEP Horizonte is superior in competitive ability to the ryegrass biotype with low-level resistance and equivalent to the susceptible biotype.

Tropical inselbergs: habitat types, adaptive strategies and diversity patterns

Inselbergs are isolated rock outcrops that rise abruptly above the surrounding plains. Granitic and gneissic inselbergs are geologically and geomorphologically old and occur throughout a broad spectrum of climatic zones. They form microclimatically and edaphically dry growth sites that support a highly specialized vegetation. Based on physiognomic criteria a number of habitat types can be distinguished that are widespread on inselbergs (e.g. ephemeral flush vegetation, monocotyledonous mats, rock pools). Three hot spots of global inselberg plant diversity can be identified which are both rich in species and endemics: a) southeastern Brazil, b) Madagascar and c) southwestern Australia.

Vasorelaxant effects of the potassium channel opener SR 47063 on the isolated human saphenous vein and rat aorta

The vasorelaxant effects of SR 47063 (4-(2-cyanimino-1,2-dihydropyrid-1-yl)-2,2-dimethyl-6-nitrochromene), a new K+-channel opener structurally related to levcromakalim, were examined in isolated human saphenous vein (HSV) and rat aorta (RA). HSV or RA rings were precontracted with either KCl or noradrenaline and cumulative relaxant concentration-response curves were obtained for SR 47063 (0.1 nM to 1 µM) in the presence or absence of 3 µM glibenclamide. SR 47063 potently relaxed HSV and RA precontracted with 20 mM (but not 60 mM) KCl or 10 µM noradrenaline in a concentration-dependent manner, showing slightly greater activity in the aorta. The potency of the effect of SR 47063 on HSV and RA was 12- and 58-fold greater, respectively, than that reported for the structurally related K+-channel opener levcromakalim. The vasorelaxant action of SR 47063 in both blood vessels was strongly inhibited by 3 µM glibenclamide, consistent with a mechanism of action involving ATP-dependent K+-channels.

ClC-5 chloride channel and kidney stones: what is the link?

Nephrolithiasis is one of the most common diseases in the Western world. The disease manifests itself with intensive pain, sporadic infections, and, sometimes, renal failure. The symptoms are due to the appearance of urinary stones (calculi) which are formed mainly by calcium salts. These calcium salts precipitate in the renal papillae and/or within the collecting ducts. Inherited forms of nephrolithiasis related to chromosome X (X-linked hypercalciuric nephrolithiasis or XLN) have been recently described. Hypercalciuria, nephrocalcinosis, and male predominance are the major characteristics of these diseases. The gene responsible for the XLN forms of kidney stones was cloned and characterized as a chloride channel called ClC-5. The ClC-5 chloride channel belongs to a superfamily of voltage-gated chloride channels, whose physiological roles are not completely understood. The objective of the present review is to identify recent advances in the molecular pathology of nephrolithiasis, with emphasis on XLN. We also try to establish a link between a chloride channel like ClC-5, hypercalciuria, failure in urine acidification and protein endocytosis, which could explain the symptoms exhibited by XLN patients.

An acid-sensing ion channel that detects ischemic pain

Ischemic pain occurs when there is insufficient blood flow for the metabolic needs of an organ. The pain of a heart attack is the prototypical example. Multiple compounds released from ischemic muscle likely contribute to this pain by acting on sensory neurons that innervate muscle. One such compound is lactic acid. Here, we show that ASIC3 (acid-sensing ion channel #3) has the appropriate expression pattern and physical properties to be the detector of this lactic acid. In rats, it is expressed only in sensory neurons and then only on a minority (~40%) of these. Nevertheless, it is expressed at extremely high levels on virtually all dorsal root ganglion sensory neurons that innervate the heart. It is extraordinarily sensitive to protons (Hill slope 4, half-activating pH 6.7), allowing it to readily respond to the small changes in extracellular pH (from 7.4 to 7.0) that occur during muscle ischemia. Moreover, both extracellular lactate and extracellular ATP increase the sensitivity of ASIC3 to protons. This final property makes ASIC3 a "coincidence detector" of three molecules that appear during ischemia, thereby allowing it to better detect acidosis caused by ischemia than other forms of systemic acidosis such as hypercapnia.