Performance, carcass and meat characteristics of two cattle categories finished on pasture during the dry season with supplementation in different forage allowance / Desempenho, características da carcaça e carne de duas categorias de bovinos de corte terminados em pastagem durante a estação seca com suplementação em diferentes ofertas de forragem

The objective this paper was to evaluate the effect of two categories of beef finished in pasture with supplementation with two herbage allowance on performance, carcass and meat characteristics. Thirty-six Guzera cattle were used, 18 steers and 18 heifers with an initial age of 20 months. There was significant difference in daily weight gain for animal category and the herbage allowance, which were higher in males and animals submitted to high herbage allowance. Steers showed higher final weight, carcass weight and forequarter yield compared with the heifers, although the hindquarter yield was higher in the heifers, however the herbage allowance did not influence these characteristics. There were not statistical differences for carcass yield, ribeye area, backfat thickness and marbling score for the animal categories and herbage allowance. The meat chemical composition of the steers did not differ of the heifers, however, the animals submitted to high herbage allowance was increase in ether extract and pH, decrease in protein percentage. It was concluded that the animal category and the herbage allowance changed the animal performance, improving performance in males and cattle submitted to high herbage allowance.(AU)

O objetivo do presente trabalho foi avaliar o efeito de duas categorias de bovinos terminados em pastagem com suplementação em duas ofertas de forragem no desempenho, na qualidade da carcaça e da carne. Foram utilizados 36 bovinos Guzerá, 18 novilhos e 18 novilhas, com idade inicial de 20 meses de idade. Observou-se diferença significativa no ganho de peso diário para categoria animal e ofertas de forragem, que foram superiores nos machos e nos animais submetidos à oferta alta de forragem. Os novilhos apresentaram maior peso final, peso de carcaça e rendimento de dianteiro em comparação com as novilhas, embora o rendimento do traseiro tenha sido maior para as novilhas, entretanto as ofertas de forragem não influenciaram essas características. Não houve diferenças estatísticas para rendimento de carcaça, área de olho de lombo, espessura de gordura subcutânea e marmorização para categorias de animais e ofertas de forragem. Quanto à composição química, a carne de novilhos não diferiu das novilhas. Os animais submetidos à alta oferta de forragem tiveram aumento no extrato etéreo e pH, redução na porcentagem de proteína. Conclui-se que a categoria animal e os níveis de forragem alteram o desempenho animal, melhorando, assim, o desempenho nos machos e nos bovinos submetidos à alta oferta de forragem.(AU)

Gene expression of thyroid-specific transcription factors may help diagnose thyroid lesions but are not determinants of tumor progression.

PURPOSE: The role of thyroid-specific transcription factors in thyroid malignancy is still poorly understood, so we investigate thyroid-specific transcription factors gene expression both in benign and in malignant thyroid nodules, aiming to study a possible clinical utility of these molecules. METHODS: We quantified TTF-1, FOXE1 and PAX8 mRNA levels, relating their expression to diagnostic and prognostic features of thyroid tumors. RNA was extracted from 4 normal thyroid tissues, 101 malignant [99 papillary thyroid carcinomas (PTC) and 2 anaplastic thyroid carcinomas] and 99 benign thyroid lesion tissues [49 goiter and 50 follicular adenomas (FA)]. RESULTS: Levels of mRNA of both FOXE1 (P < 0.0001) and PAX8 (P < 0.0001) genes, but not TTF-1 (P = 0.7056), were higher in benign than in malignant thyroid lesions. FOXE1 was able to identify malignant nodules with 75.8 % sensitivity, 76.1 % specificity, 75.8 % positive predictive value, 76.1 % negative predictive value and 75.9 % accuracy. PAX8 was able to identify malignancy with 60.6 % sensitivity, 81.1 % specificity, 76.9 % positive predictive value, 66.4 % negative predictive value and 70.6 % accuracy. Both FOXE1 and PAX8 gene expression patterns were also able to differentiate FA from the follicular variant of PTC-FVPTC. However, the investigated gene expression was neither associated with any clinical feature of tumor aggressiveness nor associated with recurrence or survival. CONCLUSIONS: We suggest that FOXE1 and PAX8 gene expression patterns may help to diagnose thyroid nodules, identifying malignancy and characterizing follicular-patterned thyroid lesions, but are not determinants of thyroid tumor progression.

Enhanced contrast efficiency in MRI by PEGylated magnetoliposomes loaded with PEGylated SPION: effect of SPION coating and micro-environment.

Magnetic core coatings modify the efficiency of nanoparticles used as contrast agents for MRI. In studies of these phenomena, care should be given to take into account possible effects of the specific micro-environment where coated nanoparticles are embedded. In the present work, the longitudinal and transverse relaxivities of superparamagnetic iron oxide nanoparticles stabilized with short-chain polyethylene glycol molecules (PEGylated SPIONs) were measured in a 7T magnetic field. PEGylated SPIONs with two different diameters (5 and 10nm) were studied. Two different PEGylated magnetoliposomes having liposome bilayer membranes composed of egg-phosphatidylcholine, cholesterol and 1,2-distearoyl-sn-glycerol-3-phosphoethanolamine-N-[methoxy PEG-2000] were also studied for their relaxivities, after being loaded with the PEGylated SPION of 5 or 10nm. This type of liposomes is known to have long residence time in bloodstream that leads to an attractive option for therapeutic applications. The influence of the magnetic core coating on the efficiency of the nanosystem as a negative contrast agent for MRI was then compared to the cumulative effect of the coating plus the specific micro-environment components. As a result, it was found that the PEGylated magnetoliposomes present a 4-fold higher efficiency as negative contrast agents for MRI than the PEGylated SPION.

The influence of the environment on the development of thyroid tumors: a new appraisal.

Most epidemiological studies concerning differentiated thyroid cancers (DTC) indicate an increasing incidence over the last two decades. This increase might be partially explained by the better access to health services worldwide, but clinicopathological analyses do not fully support this hypothesis, indicating that there are carcinogenetic factors behind this noticeable increasing incidence. Although we have undoubtedly understood the biology and molecular pathways underlying thyroid carcinogenesis in a better way, we have made very little progresses in identifying a risk profile for DTC, and our knowledge of risk factors is very similar to what we knew 30-40 years ago. In addition to ionizing radiation exposure, the most documented and established risk factor for DTC, we also investigated the role of other factors, including eating habits, tobacco smoking, living in a volcanic area, xenobiotics, and viruses, which could be involved in thyroid carcinogenesis, thus, contributing to the increase in DTC incidence rates observed.

Synthesis and characterization of magnetoliposomes for MRI contrast enhancement.

This work assesses the characteristics of magnetoliposomes of soybean phosphatidylcholine (SPC):cholesterol (Chol) loaded with superparamagnetic iron oxide nanoparticles (IONPs) stabilized with tetramethylammonium hydroxide (TMAOH) and their capacity to enhance magnetic resonance imaging (MRI) contrast. Magnetoliposomes of SPC were used for comparative studies. IONPs and magnetoliposomes were characterized using transmission electron microscopy, dynamic light scattering, SQUID magnetometry, FTIR and MRI. The saturation magnetization at 10K was ~0.06 Am(2)/kg for SPC:Chol magnetoliposomes with 7 g iron oxide/mol of lipid and ~0.05 Am(2)/kg for SPC magnetoliposomes with 21 g iron oxide/mol of lipid. As these values are associated with the number of incorporated magnetic IONPs, the saturation magnetization is 1.2 times higher for magnetoliposomes of SPC:Chol as compared with magnetoliposomes of SPC alone. The behavior of temperature dependence in both cases is typical of superparamagnetic particles. FTIR spectra evidence the increase of magnetoliposome membrane ordering with the presence of Chol. Principal component analysis (PCA) applied to FTIR spectra evidenced a clear distinction between scores for SPC:Chol, and SPC magnetoliposomes and for SPC empty liposomes. PCA applied to FTIR data differentiate magnetoliposomes from empty liposomes. MR images of aqueous phantoms obtained with and without magnetoliposomes, clearly evidence their effect on T2 image weighting.

Comparison of leaf morphology and anatomy among Malva sylvestris ("gerânio-aromático"), Pelargonium graveolens ("falsa-malva") and Pelargonium odoratissimum ("gerânio-de-cheiro") / Comparação da Morfologia e da anatomia foliar entre as espécies Malva sylvestris (gerânio-aromático), Pelargonium graveolens (falsa-malva) e Pelargonium odoratissimum (gerânio-de-cheiro)

Malva sylvestris is generally confused with Pelargonium graveolens and Pelargonium odoratissimum due to similarities in their leaf morphology. The leaves of M. sylvestris have anthocyanins with scientifically proven cytotoxic, anti-inflammatory, antitumor and antioxidant properties. The leaves of P. odoratissimum have essential oil with antibacterial and spasmolytic properties, while the essential oil from P. graveolens has antimicrobial and antifungal activity. The aim of this study was to morpho-anatomically analyze the leaves of these species, indicating differences that can be used to clarify controversies about their use as medicinal plants. To anatomically compare the structure of each plant, samples were observed by Light Microscopy and Scanning Electron Microscopy (SEM). Leaf anatomy among species was quite different. Malva sylvestris showed capitate starry tector trichomes, as well as druses and mucilaginous cells. P. graveolens and P. odoratissimum differed as to trichomes. Both species had tector and glandular trichomes, and P. graveolens is distinguished for the greater height of tector trichomes and less quantity of the latter relative to P. odoratissimum. This study allowed the detection of anatomical differences, assisting in the taxonomy and classification of these species.

Malva sylvestris é comumente confundida com Pelargonium graveolens e Pelargonium odoratissimum devido às semelhanças na morfologia foliar. As folhas de M. sylvestris possuem antocianinas com propriedades citotóxicas, antiinflamatória, antitumoral e antioxidante já comprovadas cientificamente. As folhas de P. odoratissimum apresentam óleo essencial com propriedades antibacteriana e espasmolítica, e o óleo essencial da folha de P. graveolens possui atividade antimicrobiana e antifúngica. O objetivo deste estudo foi analisar morfo-anatomicamente as folhas destas espécies, apontando diferenças que possam ser utilizadas para esclarecer controvérsias na sua utilização como planta medicinal. Com a finalidade de se comparar anatomicamente a estrutura de cada planta, as amostras foram observadas por Microscopia de Luz e Microscopia Eletrônica de Varredura (MEV). A anatomia foliar entre as espécies foi bem distinta. Malva sylvestris apresentou tricomas do tipo capitado, estrelado e tector, além de drusas e células mucilaginosas. A distinção entre P. graveolens e P. odoratissimum foi observada em relação aos tricomas. Ambas as espécies apresentaram tricomas glandulares e tectores, sendo que P. graveolens se diferencia pela maior altura dos tricomas tectores e menor quantidade destes em relação ao P. odoratissimum. Este trabalho permitiu constatar diferenças anatômicas, auxiliando na taxonomia e classificação entre estas espécies.

Caracterização anatômica e fitoquímica de folhas e rizomas de Hedychium coronarium J. Kõnig (Zingiberaceae) / Anatomical and phytochemical characterization of leaves and rhizomes from Hedychium coronarium J. Kõnig (Zingiberaceae)

Devido a grande potencialidade na utilização de Hedychium coronarium, na medicina popular e também como biorremediadora no tratamento de efluentes, objetivou-se uma diagnose dos órgãos, folha e rizoma, para elucidar resultados estruturais e fitoquímicos. A folha é anfiestomática, com predominância de estômatos na face abaxial. Em ambas as superfícies foliares há projeções de cera epicuticular sobre as paredes anticlinais das células epidérmicas. O mesofilo dorsiventral apresenta hipoderme multisseriada (3 camadas) em ambos os lados. O parênquima clorofiliano é diferenciado em paliçádico (1-2 camadas) e lacunoso (4-5 camadas) com muitos espaços intercelulares e ocorrência de idioblastos cristalíferos. Na nervura central, o aerênquima ocorre em único arco na região abaxial. Os feixes vasculares distribuem-se aleatoriamente e são de diferentes tamanhos, pequenos, médios e grandes, envolvidos por fibras. Os feixes menores localizam-se no lado abaxial da nervura. A triagem fitoquímica das folhas mostrou a presença de saponinas e ausência de taninos, antraquinonas, alcalóides e flavonóides. Por meio de Cromatografia em Camada Delgada foram identificadas as presenças de cariofileno e mirceno no óleo essencial bruto obtido a partir das folhas de H. coronarium.

Due to the great potentiality regarding the use of Hedychium coronarium in folk medicine and also as a bioremediator in effluent treatment, this study aimed to diagnose leaf and rhizome in order to elucidate structural and phytochemical results. Hedychium coronarium leaf is amphistomatal, with predominance of stomata on the abaxial surface. On both leaf surfaces, there are epicuticular wax projections over the anticlinal walls from epidermal cells. The dorsiventral mesophyll presents multiseriate (3 layers) hypoderm on both sides. The chlorophyllian parenchyma is differentiated into palisade (1-2 layers) and spongy (4-5 layers) with many intercellular spaces and some crystalliferous idioblasts. In the midrib, the aerenchyma occurs in a single arc on the abaxial surface. The vascular bundles are randomly distributed and present different sizes: small, medium and large, involved by fibers. The smallest bundles are found on the abaxial rib surface. The leaf phytochemical analysis showed the presence of saponins and lack of tannins, anthraquinones, alkaloids and flavonoids. Using thin-layer chromatography, the presence of caryophyllene and myrcene was detected in the crude essential oil obtained from H. coronarium leaves.

Quantifying the biodiversity value of tropical primary, secondary, and plantation forests.

Biodiversity loss from deforestation may be partly offset by the expansion of secondary forests and plantation forestry in the tropics. However, our current knowledge of the value of these habitats for biodiversity conservation is limited to very few taxa, and many studies are severely confounded by methodological shortcomings. We examined the conservation value of tropical primary, secondary, and plantation forests for 15 taxonomic groups using a robust and replicated sample design that minimized edge effects. Different taxa varied markedly in their response to patterns of land use in terms of species richness and the percentage of species restricted to primary forest (varying from 5% to 57%), yet almost all between-forest comparisons showed marked differences in community structure and composition. Cross-taxon congruence in response patterns was very weak when evaluated using abundance or species richness data, but much stronger when using metrics based upon community similarity. Our results show that, whereas the biodiversity indicator group concept may hold some validity for several taxa that are frequently sampled (such as birds and fruit-feeding butterflies), it fails for those exhibiting highly idiosyncratic responses to tropical land-use change (including highly vagile species groups such as bats and orchid bees), highlighting the problems associated with quantifying the biodiversity value of anthropogenic habitats. Finally, although we show that areas of native regeneration and exotic tree plantations can provide complementary conservation services, we also provide clear empirical evidence demonstrating the irreplaceable value of primary forests.

Occupational exposure in nuclear medicine in Portugal in the 1999-2003 period.

The annual doses received by the staff of nuclear medicine departments from public hospitals and private clinics and evaluated by the Individual Monitoring Service of the Radiological Protection and Nuclear Safety Department (DPRSN) of the Nuclear and Technological Institute (ITN) in Portugal, in the 5 y period from 1999 to 2003, are analysed and presented in this paper. In the 1999-2003 period, ITN-DPRSN monitored on an average 462 workers from nuclear medicine departments, which represents 6% of the 8000 workers of the medical field (approximately). The medical sector represents 80-85% of all the monitored population in Portugal. The professions of the monitored workers at nuclear medicine departments were identified by the respective departments as administrative, auxiliary, medical doctor, nuclear medicine technician, nurse, pharmacist and physicist. This information was collected at the onset of the monitoring and was updated over the last 3 y. The annual whole-body doses evaluated in the period 1999-2003 were used to derive the distribution of workers by dose intervals for every profession. The respective annual average doses and annual collective doses, as well as, the total average and total collective doses for the nuclear medicine sector were also determined and are presented. Internal radiation hasn't been monitored.

Quantitative trait analysis and geographic variability of natural populations of Zaprionus indianus, a recent invader in Brazil.

Five natural samples of a recent South America invader, the drosophilid Zaprionus indianus, were investigated with the isofemale line technique. These samples were compared to five African mainland populations, investigated with the same method. The results were also compared to data obtained on mass cultures of other populations from Africa and India. Three quantitative traits were measured on both sexes, wing and thorax length and sternopleural bristle number. We did not find any latitudinal trend among the American samples, while a significant increase in body size with latitude was observed in the Indian and, to a lesser degree, in the African populations. American populations were also characterized by their bigger size. Genetic variability, estimated by the intraclass correlation among isofemale lines, was similar in American and African populations. The intraline, nongenetic variability was significantly less in the American samples, suggesting a better developmental stability, the origin of which is unclear. A positive relationship was evident between intraline variability of size traits and the wing-thorax length correlation. Altogether, our data suggest that the colonizing propagule introduced to Brazil had a fairly large size, preventing any bottleneck effect being detected. The big body size of American flies suggests that they came from a high-latitude African country. The lack of a latitudinal dine in America seems to be related to the short time elapsed since introduction. The very rapid spread of Z. indianus all over South America suggests that it might rapidly invade North America.

Permeabilisation and solubilisation of soybean phosphatidylcholine bilayer vesicles, as membrane models, by polysorbate, Tween 80.

To understand better the wide-spread pharmaceutical use of non-ionic surfactant Tween 80 (TW), the colloidal properties of the surfactant alone and in combinations with the common phospholipid, phosphatidylcholine (PC), were studied. Static and dynamic light scattering revealed that TW solubilises PC at TW/PC approximately 2.75/1 mol/mol and that TW micelle disintegration occurs on time-scale of 2.5 min, independent of amphipath concentration. This is up to nearly 300-times faster than the TW caused dissolution of PC containing unilamellar vesicles. The apparent dissolution time of TW/PC mixed aggregates, in contrast, decelerates from >700 min to <5 min upon increasing starting total amphipath concentration, with thermal activation energy > or =24 (< or =80) kJ mol(-1). The aggregate dissolution rate in highly concentrated TW/PC suspensions reflects the dissolved polysorbate-aggregate exchange rate (approximately 6.7 x 10(-3)s(-1)) rather than TW flip-flop rate across a bilayer (>0.2 min(-1)). PC solubilisation proceeds linearly with the square-root of time, and is kinetically governed by the speed of surfactant diffusion through the bulk (D approximately 2.8 x 10(-11)m2 s(-1)). Creation of small Tween-phosphatidylcholine mixed micelles is typically preceded by pre-solubilisation structures, first in the form of deformable, strongly fluctuating, bilayer vesicles and then of elongated, presumably thread-like, mixed micelles. TW/PC mixed micelles become smaller with growing surfactant/lipid molar ratio, whereas TW/PC mixed vesicles become more and more leaky with increasing surfactant concentration. Our results highlight the molecular and kinetic aspects of polysorbate-membrane interactions and provide a rationale for the popularity of Tween surfactants in pharmaceutical products: such surfactants can solubilise fatty molecules and bilayer membranes but need quite a long time for this, which is available in pharmaceutical preparations but normally not in vivo; this makes Tweens relatively efficient and safe. Furthermore, our data could help design better ultra-deformable mixed lipid-surfactant vesicles for the non-invasive transdermal drug delivery across the skin.

Developments in the rat adjuvant arthritis model and its use in therapeutic evaluation of novel non-invasive treatment by SOD in Transfersomes.

The aim of this study was firstly to refine a rat model of arthritis, the adjuvant arthritis (AA) model, by studying the time course of the disease, introducing new evaluation methods such as haematological and biochemical parameters in order to identify the main stages of the disease. An optimisation of treatment schedule and evaluation criteria was developed. This refinement provided novel non-invasive anti-inflammatory treatment of the AA with SOD by using mixed lipid vesicles specially developed for transdermal delivery, Transfersomes (Tfs), this being the second major aim. The time course of AA includes a first stage: 1 day after the disease induction, the induced paw volume more than doubled and the paw circumference increased by approx. 50%. Two weeks later, another stage occurred where the disease shifted from the local arthritis form towards polyarthritis: an additional increase of volume and circumference of the induced and non-induced paws, occurred. The animals also started to loose weight around day 14 after the disease induction. Radiographic observable lesions increased correspondingly. Treatment of animals, started at day 1 after induction, by epicutaneous application of SOD-Tfs showed that 1 mg SOD/kg body weight is more efficient than 0.66 mg SOD /kg body weight. As a positive control, SOD liposomes intravenously injected were used for comparison and confirmed the biological efficiency of epicutaneously applied SOD in Tfs. SOD solution and empty Tfs epicutaneously applied exerted no effect. In addition, epicutaneous application of SOD-Tfs used prophylactically was able to suppress the induced rat paw oedema. Radiographic images showed less joint lesions in SOD-Tfs treated animals in comparison with control and placebo treated rats. It was shown for the first time that SOD incorporated into Tfs and applied onto a skin area not necessarily close to the inflamed tissue is able to promote non-invasive treatment of induced arthritis.

Databases in use at the individual monitoring service of ITN-DPRSN.

In this work, the databases developed for routine use at the Individual Monitoring for External Radiation Service (IMS) of the Radiological Protection and Nuclear Safety Department (DPRSN) at the Nuclear and Technological Institute (ITN) in Portugal are presented. At the IMS there are two dosimetry systems running simultaneously, one based on film and the other one on thermoluminescent detectors (TLD). Two databases were initially and independently home-developed in order to meet each service's needs. A few modifications were introduced and while each service's requirements were maintained where needed, the databases were adapted in order to store the same type of information relative to the facilities and monitored workers, as well as to produce similar shaped reports and technical information. The necessary administrative features of the services were considered in the database development, made user-friendly and welcomed by the ordinary users. The improvements allowed a more direct analysis of the annual doses and an easy identification of professions and practices associated with higher dose values.

The effect of cholate on solubilisation and permeability of simple and protein-loaded phosphatidylcholine/sodium cholate mixed aggregates designed to mediate transdermal delivery of macromolecules.

Carriers for non-invasive administration of biologically important antioxidant enzymes Cu,Zn-superoxide dismutase (SOD) and catalase (CAT) were developed. Solubilisation and permeabilities of various soybean phosphatidylcholine/sodium cholate (SPC/NaChol) mixtures, mainly in the form of lipid bilayers, focussing on system properties relevant for non-invasive enzyme delivery were investigated in this work. Static and dynamic light scattering measurements gave information on the behaviour of the systems containing up to 40 mM NaChol and 30.6-1.2 mM SPC in the final suspension. The average size of such mixed aggregates was in the 100-200 nm range. Suspension turbidity decreased by 50% upon increasing nominal molar detergent/lipid ratio to NaChol/SPC = 7 and 1.25, in case of SPC = 1.2 and 19.6 mM, respectively. The effective NaChol/SPC molar ratio in bilayers saturated with the detergent was found to be: R(e)(sat) = 0.70 +/- 0.01; bilayer solubilisation point corresponded to R(e)(sol) = 0.97 +/- 0.02, independently of enzyme loading. Vesicles became very permeable to SOD when membrane bound NaChol concentration exceeded 13.7 mM, in case of total starting lipid concentration of 138 mM diluted to SPC = 19.6 mM. Specifically, we measured a 50% loss of SOD from the vesicles with an aggregate-associated molar detergent ratio NaChol/SPC approximately 0.7, which is near the saturation but well below the solubilisation limit. Calcein efflux from such vesicles was compared with SPC/NaChol/SOD mixed aggregates. Our results should contribute to the future design of vesicle mediated transdermal delivery of antioxidant enzymes.

Caracterização biométrica e química da folha de Mentha pulegium x spicata (Lamiaceae) / Biometric and chemical characterization of Mentha pulegium x spicata (lamiaceae) leaves

O híbrido Mentha pulegium x spicata, também conhecido como poejo de praia, é uma planta perene, rasteira, ramosa, com caule arroxeado, folhas opostas, lanceoladas e serreadas no bordo, apresentando odor característico. O objetivo do presente trabalho foi realizar um estudo da anatomia foliar, incluindo um estudo de biometria tecidual e análise quantitativa de tricomas secretores/mm2 e de estômatos/mm2 em ambas as faces da folha, além de uma análise química do óleo essencial. Foram efetuadas lâminas permanentes para análise anatômica do limbo foliar e também lâminas da impressão foliar para a contagem do número de tricomas e estômatos. A análise química foi efetuada através da extração do óleo essencial por arraste à vapor d'água e analisado por CG-EM. Os tricomas capitados e peltados estão presentes em ambas as faces da folha, porém predominam na superfície abaxial. A análise de variância mostrou que há diferenças significativas para o número de tricomas capitados e tectores entre as superfícies adaxial e abaxial, mas não são significativas para o tricoma peltado. O óleo essencial analisado, mostra a presença do componente majoritário, trans-epóxido de piperitona, responsável por mais de 80% da composição relativa no óleo bruto

Design and characterization of enzymosomes with surface-exposed superoxide dismutase.

Superoxide dismutase (SOD) was chemically modified by covalent linkage of fatty acid chains to the accessible epsilon-amino groups of the enzyme. This acylation method gave rise to a different enzyme entity (Ac-SOD) as evidenced by different physicochemical properties such as octanol/water partition coefficient and isoelectric point (pI) as compared to SOD. Ac-SOD was incorporated in conventional and long-circulating liposomes (LCL) and characterized in terms of incorporation efficiency, protein to lipid ratio (Prot/Lip), enzymatic activity retention and zeta potential. The observation that Ac-SOD liposomes present enzymatic activity on their external surface indicates that these formulations can act independent of rate and extent of enzyme release as required in case of SOD liposomes. The decrease of superficial charge of liposomal formulations containing Ac-SOD, as compared to SOD liposomes, may be related to the negatively charged enzyme molecules localized on the liposome surface. The comparative characterization of Ac-SOD and SOD liposomal formulations evidenced that the two enzyme forms differ substantially regarding their intraliposomal location: SOD tends to be localized in the internal aqueous spaces, whereas Ac-SOD is expected to be localized in the lipid bilayers of the liposomes, partially buried into the outer surface and exposed to the external medium. These liposomal structures with surface-exposed SOD were designated as Ac-SOD enzymosomes. The properties of these enzymosomes may influence the therapeutic effect, as the release of the enzyme from extravasated vesicles is no longer a necessary requirement for achieving dismutating activity within the inflamed target site.

Occupational exposure in Portugal in 1999.

This study reports the occupational radiation doses for external exposure received in 1999 by the radiation workers monitored by the Radiological Protection and Nuclear Safety Department (DPRSN) in Portugal. Occupational exposures arise from conventional industry, research laboratories, the health or medical sector, and mining. There are no nuclear power plants in the country. There are two dosimetry systems running simultaneously at DPRSN, one based on film dosimetry and the other on thermoluminescence dosimetry (TLD). In 1999, 8400 persons were monitored, 3100 with film and 5300 with TLD and the data presented in this report were obtained by using both technologies. The annual mean effective doses received from external radiation in the different fields of activity and the distribution of the annual effective dose by dose intervals are presented. The collective annual dose by field of activity is estimated and the contribution to the total annual collective dose is determined.

An analytical methodology to quantify the incorporation of enzymes in polyalkylcyanoacrylate nanoparticles based on size exclusion chromatography.

The performances of different methods of quantification of protein (methods based on direct spectrophotometric and spectrofluorimetric analysis, chemical reactions and liquid chromatography) to quantify the amount of enzyme incorporated into polyalkylcyanoacrylate nanoparticles, were compared. A methodology based on size exclusion chromatography was selected. The performances of the analytical method to quantify the enzymes L-asparaginase and superoxide dismutase in different polymerization media of poly-isobutilcyanoacrylate, were evaluated. The quantification of superoxide dismutase in the presence of esterase, enzyme used to solubilize nanoparticles, was attempted. An adequate separation between enzyme and the other components of polymerization media was achieved, so the selectivity of the method is adequate to the quantification of an enzyme in polymerization medium, either before or after polymerization. Although lack of selectivity of the column to separate enzymes was observed. The retention time of L-asparaginase and superoxide dismutase in polymerization medium are, respectively, 7.4 and 7.5. Linear correlation between peak area and enzyme concentration were observed for both enzymes in the concentration range from 10 to 80 micrograms ml-1, either before or after polymerization and in different polymerization media. This SE-HPLC analytical methodology is adequate to determine the degree of incorporation of enzymes in polyalkylcyanoacrylate nanoparticles as evidenced by the linear responses of the chromatographic method, the reproductibility of repeated sample injections and the precision of the quantification of enzyme concentration.

Biochemical characterization of an L-asparaginase bioconjugate.

In this work is characterized a bioconjugate of L-asparaginase, obtained by linkage of palmitic acid chains to the native enzyme in the presence of substrate as a protein protective molecule. Comparisons between isoelectric points, hydrophobicity, pH, and temperature profiles for the bioconjugate and the native enzyme were performed. A shift of pI from 5.03 to 4.58 was observed after conjugation. The modified enzyme evidences a 10-fold increase of the hydrophobicity. A small shift from 7.5 to 7 of the pH for maximal catalytic activity and a 5 degree C increase of temperature for maximal activity were observed with conjugation. Stability studies in human serum and on storage evidence similar behaviors for both bioconjugate and native enzyme. The retention of catalytic activity of the bioconjugate is dependent on the presence of micelles. The bioconjugate evidenced 65% retention of activity when catalytic activity was assayed without a surfactant and 98-100% retention of activity when catalytic activity was assayed in the presence of surfactant micelles. The kinetic characteristics of the bioconjugate and of the native enzyme, in micelles of different hydrophobicities, were compared. The Michaelis constant of native enzyme is 0.030 mM, independent of the surfactant, and the Michaelis constant of the bioconjugate varies with the surfactant, from 0.036 to 0.046 mM.

Yeast succession in the Amazon fruit Parahancornia amapa as resource partitioning among Drosophila spp.

The succession of yeasts colonizing the fallen ripe amapa fruit, from Parahancornia amapa, was examined. The occupation of the substrate depended on both the competitive interactions of yeast species, such as the production of killer toxins, and the selective dispersion by the drosophilid guild of the amapa fruit. The yeast community associated with this Amazon fruit differed from those isolated from other fruits in the same forest. The physiological profile of these yeasts was mostly restricted to the assimilation of a few simple carbon sources, mainly L-sorbose, D-glycerol, DL-lactate, cellobiose, and salicin. Common fruit-associated yeasts of the genera Kloeckera and Hanseniaspora, Candida guilliermondii, and Candida krusei colonized fruits during the first three days after the fruit fell. These yeasts were dispersed and served as food for the invader Drosophila malerkotliana. The resident flies of the Drosophila willistoni group fed selectively on patches of yeasts colonizing fruits 3 to 10 days after the fruit fell. The killer toxin-producing yeasts Pichia kluyveri var. kluyveri and Candida fructus were probably involved in the exclusion of some species during the intermediate stages of fruit deterioration. An increase in pH, inhibiting toxin activity and the depletion of simple sugars, may have promoted an increase in yeast diversity in the later stages of decomposition. The yeast succession provided a patchy environment for the drosophilids sharing this ephemeral substrate.