A broad tuneable birdcage coil for mouse 1H/19F MR applications.

In this paper, we present the design and implementation of a 1H/19F volume coil for mouse body magnetic resonance (MR) imaging and spectroscopy using a high magnetic field (4.7 T). By changing the geometry of the coil rungs to include both nuclei for MR experiments, this innovative coil can be tuned over an extremely wide range of frequency. The coil, 45 mm in diameter and 55 mm in length, consists of a 12-rung birdcage-like structure. Using two types of tuning, the coil can generate a sufficiently homogeneous B1+ electromagnetic field within a working volume optimized for laboratory mouse. The first tuning involves changing the resonance frequency over a large frequency range. The electrical capacitance between the wires can be adjusted to reflect changes in the length of the coil. The second tuning comprises a habitual tuning transformer for precise detection in a narrow band. In contrast to widely used multinuclear coils, the coil presented here features only one resonance peak and can be manipulated according to the Larmor frequencies given for 1H and 19F. The coil was successfully tested using full-wave simulations of magnetic and electric field distributions under in vivo MR conditions.

Polymer nitric oxide donors potentiate the treatment of experimental solid tumours by increasing drug accumulation in the tumour tissue.

The delivery of nitric oxide (NO) specifically to solid tumours was explored in this study as a strategy to augment the passive accumulation of nanomedicines in tumours induced by the Enhanced Permeability and Retention (EPR) effect. An increase in accumulation was achieved by the binding of the chemical precursor of NO, based on an organic nitrate, to a water-soluble synthetic polymer drug carrier. Four structurally different N-(2-hydroxypropyl)methacrylamide (HPMA)-based polymer NO donors were synthesized. Depending on their chemical structure, two of these donors were hydrolytically stable, while two rapidly released the parent nitrate under acidic conditions, mimicking the intracellular environment. The polymer NO donors were shown to overcome the drawbacks related to low-molecular-weight NO releasing compounds, namely systemic toxicity, lack of site specificity, and fast blood clearance. The NO donors showed intracellular NO release upon incubation with tumour cells. In vivo, they potentiated the EPR effect, resulting in an increased accumulation of polymer-bound cytotoxic drug doxorubicin (Dox) in EL4 T-cell lymphoma inoculated in mice. This led to a better therapeutic outcome in the treatment of lymphoma with the high-molecular-weight polymer conjugates carrying Dox but not in the treatment with the free Dox. The localized augmentation of the EPR effect via the tumour-specific NO delivery system can be viewed as a promising strategy to potentiate polymer-based tumour therapy without increasing systemic toxicity.

Distribution, colour polymorphism and habitat use of the African killifish Nothobranchius furzeri, the vertebrate with the shortest life span.

Intensive collection in southern Mozambique across and outside the potential range of Nothobranchius furzeri, the species with the shortest recorded life span among vertebrates used as a model in ageing research, revealed that, contrary to previous data, it is a widespread species. It occurs in small freshwater pools south of the Save River and north of the Incomati River, including basins of the Limpopo, Changane, Chefu, Mazimechopes and Vaneteze Rivers. During collection in February 2008 (the second part of the rainy season), populations were strongly female biased (mean, 28% of males across 19 populations), and there was a spatial pattern in female bias among metapopulations. Populations varied in the proportion of male colour morphs. Fourteen populations were composed exclusively of the red male phenotype, three populations of the yellow male phenotype and 12 populations were mixed. Overall, the red phenotype was more common, but there was strong geographical variation in morph proportion, with yellow males more abundant at the periphery and red male dominance in the centre of the range of N. furzeri in the Limpopo basin. Nothobranchius furzeri was sympatric with Nothobranchius orthonotus (35% of investigated pools) and Nothobranchius rachovii (27% of sites). Analysis of habitat use of N. furzeri is presented; N. furzeri was associated with pools containing a soft muddy substratum and turbid water.

[Incidence of inhibitory substance-residues in meat and organs of slaughter calves fed with milk feed mixtures]. / Výskyt reziduí inhibicních látek v mase a orgánech jatecných telat krmených mlécnou krmnou smesí

From 1st January 1974 till 30th April 1975 the frequency of the occurrence of growth inhibiting substances in meat and organs of slaughter calves on milk feeding was studied. Meat and organs of 11 226 calves on milk feeding (the meat and organs were judged, after the veterinary inspection, as fit for concumption), of 189 emergency-slaughtered calves on milk feeding and of 751 forced--slaughtered calves were examined by means of a diffusion plate method with the tester stran B. subtilis (ATCC 6633); the method had been, on trial, introduced into State Veterinary Institutes. The positive findings in all groups studied considerably fluctuated and showed average values as follows: 6.3% --14.28% --22.5%. At the same time, 71 clinically healthy calves were examined; they were slaughtered in the slaughter -- houses of M. meat processing plant after having been reared in a traditional way. In this group, all results concerning the examination of the presence of growth inhibiting substances were negative.

[Arsenic contamination in imported sea fish and fish products made from them]. / Kontaminace arzénem u dovázených morskáych ryb a výrobku z nich

The rate of arsenic contamination in sea-fish is, in comparison with freshwater fish, relatively high. An investigation of five kinds of sea-fishes--of mackerel, herring, cod, tunny, and plaice--that are most frequently put on the market showed that a permitted value up to 1 mg As per 1 kg of fish meat was found only in 24.0% of mackerel, 9.5% of herring, 33.4% of cod, 57.0% of plaice and 0.0% of tunny. Further investigation of dressed fish--of fillets--revealed that 15.8% of herring fillets and 0.0% of cod fillets met the permitted value. The values of a majority of studied sea-fish samples ranged from 1 to 2 mg As per 1 kg: 52% of mackerel, 63.5% of herring, 66.6% of cod, 43% of tunny, 28% of plaice. It is necessary to revalue the permitted values of arsenic content in sea-fish and in products made from their meat and to defend the upper limits of the permitted arsenic value, which will require the purposeful organization of effective laboratory tests the results of which will directly influence an estimation of fish raw material and will provide the corresponding hygienic quality of fish and fish products.