EXPERIMENTAL AND COMPUTATIONAL EVALUATION OF EFFECTIVE CENTRE FROM A LONG COUNTER AT NEUTRON METROLOGY LABORATORY IN BRAZIL.

A long counter detector was manufactured by the Institute of Advanced Studies (IEAV) and was characterised in the neutron low scattering room at Brazilian National Ionising Radiation Metrology Laboratory (LNMRI/IRD) to deploy a secondary Standard for neutron fluence. The effective centre was measured experimentally with 252Cf+D2O, 252Cf, 241AmBe and 238PuBe neutron sources, having average energies from 0.55 to 4.16 MeV. The experimental arrangement and detector construction were carefully reproduced in Monte Carlo simulations, and the computational results were found to be in good agreement with those from experiment.

IMPROVEMENTS IN THE THERMAL NEUTRON CALIBRATION UNIT, TNF2, AT LNMRI/IRD.

The standard thermal neutron flux unit, TNF2, in the Brazilian National Ionizing Radiation Metrology Laboratory was rebuilt. Fluence is still achieved by moderating of four 241Am-Be sources with 0.6 TBq each. The facility was again simulated and redesigned with graphite core and paraffin added graphite blocks surrounding it. Simulations using the MCNPX code on different geometric arrangements of moderator materials and neutron sources were performed. The resulting neutron fluence quality in terms of intensity, spectrum and cadmium ratio was evaluated. After this step, the system was assembled based on the results obtained from the simulations and measurements were performed with equipment existing in LNMRI/IRD and by simulated equipment. This work focuses on the characterization of a central chamber point and external points around the TNF2 in terms of neutron spectrum, fluence and ambient dose equivalent, H*(10). This system was validated with spectra measurements, fluence and H*(10) to ensure traceability.

Levantamento de plantas medicinais nativas da Fazenda Azulão em Dourados-MS / Inventory of native medicinal plants on a farm in Dourados-MS

O presente trabalho teve por objetivo identificar as espécies medicinais nativas em um fragmento de mata situada na Fazenda Azulão, em Dourados/MS, baseando-se no conhecimento popular de mateiros da região, com intuito de gerar subsídios para perpetuar a preservação, a diversidade e variabilidade das espécies, bem como, incentivar populações locais a valorizar e preservar esses recursos naturais, retardando o impacto sobre a biodiversidade. Partes das plantas indicadas como medicinais foram coletadas, as quais foram identificadas mediante literaturas especializadas e por comparações com plantas depositadas no Herbário da Cidade Universitária de Dourados. Foram identificadas 61 espécies distribuídas em 35 famílias e 53 gêneros. As famílias Asteraceae (9), Fabaceae (5) e Piperaceae (4) foram as que apresentaram o maior número de espécies. Dentre as formas de vida encontradas na vegetação nativa do local, as espécies medicinais de hábito arbustivo (39,34%) foram as que apresentaram os maiores valores, seguido pelas herbáceas (27,86%), arbóreas (24,6%), e lianas (8,2%). As partes das plantas mais utilizadas são as folhas, seguidas da raiz e casca. Com base nos resultados obtidos nesse estudo, as indicações da utilização das plantas medicinais podem fornecer subsídios para estudos bioquímicos e farmacológicos, diminuindo os custos e o tempo na extração de princípios ativos, bem como, permitir o fortalecimento do conhecimento cultural da comunidade local, incentivando a preservação ambiental de diversas espécies medicinais utilizadas na região. Novos estudos devem ser conduzidos no Estado do Mato Grosso do Sul, a fim de se garantir o registro de dados mais precisos sobre as espécies medicinais ocorrentes.

This study aimed to identify the native medicinal species in a forest fragment located at Azulão Farm in Dourados/ MS, based on the popular knowledge of the bushmen of the region, aiming to generate data to perpetuate the preservation, diversity and variability of the species, as well as to encourage local people to value and preserve these natural resources, slowing the impact on biodiversity. Samples of plants indicated as medicinal were collected, and then identified by the specialized literature and by comparison with plants deposited in the Herbarium of the University City of Dourados. We identified 61 species belonging to 35 families and 53 genera.The Asteraceae (9), Fabaceae (5) and Piperaceae (4) showed the largest number of species. Among the life forms found in the local native vegetation, the medicinal species of shrubby habit (39.34%) were the ones that presented the highest values, followed by the herbaceous (27.86%), trees (24.6%), and lianas (8.2%). The most frequently used plant parts are the leaves, followed by the roots and bark. Based on the results of this study, the indications of use of medicinal plants can provide subsidies for biochemical and pharmacological studies, reducing the costs and the time for the extraction of active ingredients, also contributing with the cultural knowledge of the local community, encouraging environmental preservation of many medicinal species used in the region. Further studies should be conducted in the State of Mato Grosso do Sul, in order to ensure the registration of more accurate data on the existing medicinal species.

Successful HAART is associated with high B-chemokine levels in chronic HIV type 1-infected patients.

Chemokine receptors are used by HIV-1 for entry into CD4+ T cells. The beta-chemokines are capable of inhibiting HIV replication. This study measured beta-chemokine macrophage inflammatory protein (MIP)-1alpha and MIP-1beta levels and determined the CCR5 and CXCR4 expression on T cells in HIV-1-infected patients treated with HAART. The time of known HIV infection and time of HAART use were similar between failure and successful groups. The CD4+ T cell nadir was 163 vs. 251 cells/mm3, p = 0.07, for failure and successful groups, respectively. The successfully treated group, when compared with the failure group, had a higher median CD4+ T cells count (667 vs. 257 cells/mm3; p = 0.003) as well as higher spontaneous MIP-1alpha (median of 4390 vs. 802 pg/ml, p = 0.03) and MIP-1beta (median of 2416 vs. 1117 pg/ml, p = 0.001) levels. The untreated patients had a higher number and intensity of CCR5- and CXCR4-expressing T cells. Higher levels of chemokines were not related to nadir CD4+ T and current CD8+ T cell counts. Successfully treated patients were able to produce higher amounts of beta-chemokines and normalize the coreceptor overexpression on T cells. These findings may have clinical implications, such as a new strategy of using chemokines as adjuvants in anti-HIV therapy.

Increase of melanogenesis by retinoic acid: an ultrastructural and morphometric study.

Melanin is a dark pigment protecting the skin against UV radiation in some organisms. Studies on invasion and metastasis using retinoic acid as inhibitor agent are well known, but its role in melanin production (melanogenesis), especially at ultrastructural level and using morphometry were not well studied. In the present study, we analyzed the effects of retinoic acid on the melanosomes in B16F10 melanoma cells. These organelles were identified and quantified using routine electron microscopy and the specific HMB45 antibody. Other approaches such as immunofluorescence, and flow cytometry were also used. Our results indicated that retinoic acid increased the melanogenesis process in B16F10 melanoma cells. Furthermore, this work also provided evidence that this substance interferes at the subcellular level altering the numerical density of melanosomes, as well as the relative volume of the nucleus and nucleolus. In addition, the cells displayed altered morphology and an increase in the percentage of the relative volume of melanosomes, mainly the stages II-III and IV, leading to melanin formation. Furthermore, a decrease in the cells number after retinoic acid treatment was also observed.

Streptozotocin-induced diabetes: significant changes in the kinetic properties of the soluble form of rat bone alkaline phosphatase.

A soluble form of an alkaline phosphatase, obtained from the osseous plate of streptozotocin-induced diabetic rats, was purified 90-fold with a yield of 26%. The calculated Mr of the purified enzyme was 80,000 by denaturing polyacrylamide gel electrophoresis and 160,000 by gel filtration on Sephacryl S-300, suggesting a dimeric structure for its native form. In the absence of metal ions, the p-nitrophenylphosphatase activity of the purified enzyme was 4223.1 U/mg. Magnesium or calcium ion concentrations up to 2 mM increased the specific activity of the enzyme to 9896.5 and 10,796.2 U/mg, respectively. The enzyme was stimulated to a lesser extent by MnCl2 (5390.1 U/mg) and CoCl2 (5088.2 U/mg). The purified soluble alkaline phosphatase showed a broad substrate specificity, and among the less hydrolyzed substrates were pyrophosphate (1517.6 U/mg) and bis-p-nitrophenylphosphate (499.6 U/mg). The enzyme was relatively stable at 45 degrees for periods as long as 180 min, but was denatured rapidly above 50 degrees, following first order kinetics with T1/2 values ranging from 3.5 to 57.7 min. The results reported herein suggested that the soluble form of alkaline phosphatase from streptozotocin-induced diabetic rats had its kinetic properties altered, apparently as a consequence of changes in metal-binding properties.