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Capsules from pathogenic and non-pathogenic cryptococcus spp. manifest significant differences in structure and ability to protect against phagocytic cells
No full text11 p. : il.Capsule production is common among bacterial species, but relatively rare in eukaryotic microorganisms. Members of the fungal Cryptococcus genus are known to produce capsules, which are major determinants of virulence in the highly pathogenic species Cryptococcus neoformans and Cryptococcus gattii. Although the lack of virulence of many species of the Cryptococcus genus can be explained solely by the lack of mammalian thermotolerance, it is uncertain whether the capsules from these organisms are comparable to those of the pathogenic cryptococci. In this study, we compared the characteristic
of the capsule from the non-pathogenic environmental yeast Cryptococcus liquefaciens with that of C. neoformans.
Microscopic observations revealed that C. liquefaciens has a capsule visible in India ink preparations that was also efficiently
labeled by three antibodies generated to specific C. neoformans capsular antigens. Capsular polysaccharides of C. liquefaciens were incorporated onto the cell surface of acapsular C. neoformans mutant cells. Polysaccharide composition determinations in combination with confocal microscopy revealed that C. liquefaciens capsule consisted of mannose, xylose, glucose, glucuronic acid, galactose and N-acetylglucosamine. Physical chemical analysis of the C. liquefaciens
polysaccharides in comparison with C. neoformans samples revealed significant differences in viscosity, elastic properties
and macromolecular structure parameters of polysaccharide solutions such as rigidity, effective diameter, zeta potential and
molecular mass, which nevertheless appeared to be characteristics of linear polysaccharides that also comprise capsular
polysaccharide of C. neoformans. The environmental yeast, however, showed enhanced susceptibility to the antimicrobial
activity of the environmental phagocytes, suggesting that the C. liquefaciens capsular components are insufficient in protecting yeast cells against killing by amoeba. These results suggest that capsular structures in pathogenic Cryptococcus species and environmental species share similar features, but also manifest significant difference that could influence their
potential to virulence
Ambiente seguro e inteligente : grupo de trabalho define as primeiras ações da gestão integrada
No full text8 f.: il. - Ano 27, n. 436 (mai/jun/2012)O Jornal Na Medida é uma publicação interna do Inmetro e Rede Brasileira de Metrologia Legal e Qualidade. Você pode participar enviando notícias para [email protected] partir dessa edição, você já conta com a opção de "folhear" o Na Medida na versão on line através do endereço - http://www.inmetro.gov.br/imprensa/naMedida.asp
Efficacy of miltefosine treatment in Leishmania amazonensis-infected BALB/c mice
No full text6 p. : il., tab.Leishmaniasis is one of the most serious worldwide diseases caused by protozoan parasites of the Leishmania genus, affecting millions of people around the world. All currently available treatments present
severe toxic side effects, require long-term compliance, cause serious side effects and are uncomfortable for patients. Leishmania amazonensis, a species endemic to Brazil, causes severe localised or diffuse skin lesions in humans. Owing to the unsatisfactory nature of the currently available chemotherapies, new approaches have been assessed for improved therapeutic intervention strategies against leishmaniasis.
Miltefosine is an alkylphospholipid analogue that exhibits potent activity against the different clinical manifestations of leishmaniasis. Thus, the aim of this study was to investigate the long-term efficacy of miltefosine in BALB/c mice infected with L. amazonensis owing to the lack of a profound
study demonstrating its dose-dependent and long-term effects. It was observed that animals treated with 20–50 mg/kg/day of miltefosine exhibited a significant dose-dependent reduction in lesion size;
furthermore, in mice receiving higher doses, lesions disappeared after the end of treatment. To confirm a possible parasitological cure, mice up to 250 days after the end of treatment were analysed. No lesions or presence of parasite DNA were found in mice treated with 30, 40 and 50 mg/kg/day of miltefosine. In summary, these results show that miltefosine may be used to treat cutaneous leishmaniasis caused by L.
amazonensis, alone or as combination therapy
Na Medida: jornal interno do Inmetro e da Rede Brasileira de Metrologia Legal e Qualidade
No full text8 f.: il. - Ano 27, n. 435 (abr.2012)O Jornal Na Medida é uma publicação interna do Inmetro e Rede Brasileira de Metrologia Legal e Qualidade. Você pode participar enviando notícias para [email protected] partir dessa edição, você já conta com a opção de "folhear" o Na Medida na versão on line através do endereço - http://www.inmetro.gov.br/imprensa/naMedida.asp
Gut bacterial communities in the giant land snail achatina fulica and their modification by sugarcane-based diet
No full text6 p. : il.The invasive land snail Achatina fulica is one of the most damaging agricultural pests worldwide representing a potentially
serious threat to natural ecosystems and human health. This species is known to carry parasites and harbors a dense and
metabolically active microbial community; however, little is known about its diversity and composition. Here, we assessed
for the first time the complexity of bacterial communities occurring in the digestive tracts of field-collected snails (FC) by
using culture-independent molecular analysis. Crop and intestinal bacteria in FC were then compared to those from groups
of snails that were reared in the laboratory (RL) on a sugarcane-based diet. Most of the sequences recovered were novel and
related to those reported for herbivorous gut. Changes in the relative abundance of Bacteroidetes and Firmicutes were
observed when the snails were fed a high-sugar diet, suggesting that the snail gut microbiota can influence the energy
balance equation. Furthermore, this study represents a first step in gaining a better understanding of land snail gut
microbiota and shows that this is a complex holobiont system containing diverse, abundant and active microbial
communities
Cytocompatibility and structural arrangement of the collagen fibers: an in vitro and in vivo evaluation of 5% zinc containing hydroxyapatite granules
No full text6 p. : il., tab.Hydroxyapatite (HA) is one of the most employed materials for bone therapy due to its structural similarity with bone, its biocompatibility and physicochemical properties. Additionally, HA performance may be improved by ionic substitution of calcium with divalent bioactive metallic cations such as zinc. In this context, zinc incorporation into HA have been well studied, in spite of conflicting results regarding its biocompatibility: while previous reports on in vitro cytocompatibility have described 5% zinc containing HA (ZnHA) as slightly cytotoxic, this material presented an excellent response on in vivo studies. In order to bring more information on ZnHA biocompatibility, we performed a multiparametric assay evaluating sequentially on the same cells three different viability parameters: mitochondrial activity (XTT), membrane integrity (Neutral Red) and cell density (Crystal Violet Dye Exclusion test). Additionally, we intended to complement the existing data on ZnHA in vivo performance, by assessing its ability to affect the
arrangement of collagen fibers on the grafted area, an important indicative of bone maturation.
MC3T3-E1 cells were exposed to 24-hours extracts of ZnHA or stoichiometric HA on culture medium (DMEM) and cell viability was assayed. ZnHA was very cytocompatible, since the levels of viable cells on all 3 tests were similar to the HA and polystyrene (negative control) extracts, but significantly higher than cells treated with 4% phenol (positive control). For the in vivo studies, critical size defects in rats calvaria were filled with HA or ZnHA granules. The histological evaluation after 30 and 180 days revealed an increase along time. Event tough ZnHA is cytocompatible the presence of Zn was unable to alter the interaction between collagen fibers and
the mineral bone phase, as compared to stoichiometric HA
Genetic variation in MMP20 contributes to higher caries experience
No full text6 p. : il.Matrix metalloproteinases play an important role during the initial process of enamel
development and therefore may play a role in caries.
Objectives: To evaluate the association between MMP20 and caries experience in Brazilian children.
Methods: Eligible unrelated children with or without caries were evaluated using a cohort
design. Demographic data and oral health habits were obtained though a questionnaire.
Caries data was collected by clinical examination. Genotyping of the selected polymorphism was carried out by real-time PCR from genomic DNA. Allele and genotype frequencies were compared between groups with distinct caries experience and oral health habits.
Results: Of 388 subjects, 161 were caries free children. There were no differences between caries levels and genotype distribution in the total cohort. When ethnic background was considered, differences in genotype distribution were observed in caries free children vs. children with caries in Caucasians (p = 0.03). Differences could also be seen when poor oral hygiene was used to stratify the analysis ( p = 0.02). Regression analysis, adjusted for genotype and ethnicity, confirmed that ingestion of sweets between meals increases the risk of presenting carious lesions ( p = 0.00001; OR = 2.33; 95%CI 1.53–3.54).
Conclusion: Variation in MMP20 may be associated with caries experience mainly in Caucasian subjects with poor oral health habits
Biocompatibility of carbonated hydroxyapatite nanoparticles with different crystallinities
No full text6 p. : il., tab.Carbonated apatite (CHA) is commonly considered a promising synthetic material for
biomedical applications in orthopedic and dental surgery due to its biocompatibility, bioresorption and bioactivity. CHA5, CHA37 and CHA90 powders were synthesized from wet method and the DRX patterns showed that the crystallinity and particle size of CHA samples increased proportionally with the synthesis temperature. Powder extracts medium were obtained from each sample to interact with MC3T3-E1 osteoblastics cells. It was evaluated morphology, citotoxicity,
pH and Ca2+ concentration. Citotoxicity assays showed high metabolic activity on all samples when compared to control. The polygonal shaped and the confluent monolayer observed in control cells progressively changed according to the crystallinity increase of samples. Cells under mitosis and
spindle-like shaped where the main alterations observed. In addition the cell viability could be sensitive to the acid reactivity and crystallinity of carbonated apatite samples
Periosteal derived cells for bone bioengineering: a promising candidate
No full text5 p. : il., tab.Purpose: Over the last years so many efforts have been made in order to indentify natural sources of osteogenic cells for the success of bone bioengineering. Among them, periosteum tissue has emerged as an interesting candidate. Thus, we decided to evaluate the osteogenic potential of periosteal-derived cells by describing a sequence of biological events since initial morphological changes to mineralization of extracellular matrix (ECM).
Methods: Periosteal-derived cells were obtained from calvarial of adult rats. After the primary culture and expansion, the adherent cells were cultured at 7, 14, 21 and 28 days under a classical osteogenic culture medium in order to evaluate the differentiation of those cells in mature
osteoblast. It was monitored by evaluating a time-line of alkaline phosphatase (ALP) activity (biomarker of osteoblast differentiation) and afterwards nodules of mineralization (measured by von Kossa staining and calcium content).
Results: Analysis from phase-contrast microscopy revealed mainly morphological changes ranging since fibroblast-shaped (7 days, semi-confluent culture at exponential growth) to polyhedralshaped cells (14–28 days, confluent culture during differentiation process). ALP activity was linearly increased since 14–28 days while amount of protein remained unchanged. Interesting, our data from von Kossa staining reveled a highest incidence of mineralization nodules at 28 days.
Conclusion: Taken our results together, we can suggest that periosteal-derived cells present an interesting potential to differentiate in mature osteoblast able to promote mineralization in vitro by incorporating to ECM circulating calcium from extracellular compartment. From our point of view, this source of osteogenic cells can be explored by bioengineers in order to advance therapeutic protocols able to solve bone degenerative lesions
Temperature
No full text1 pôster : il.O pôster TEMPERATURA destaca a importância das medições exatas da grandeza para a maioria dos setores da vida humana e do Inmetro como guardião dos padrões nacionais. A partir da história da termometria, explica as diferenças entre os tipos de termômetros (líquidos, de mercúrio ou álcool, termopares, pirômetros) e entre as escalas de temperatura. A definição do kelvin (K), a unidade de base, é relacionada à Escala Internacional de Temperatura de 1990. Há uma lista com a temperatura, em graus Celsius de algumas substâncias e processos: fusão termonuclear, superfície e centro do Sol, fusão do vidro e aço, ponto de fusão do ouro, fusão e ebulição da água, ponto mais frio na superfície da Terra, armazenamento criogênico de nitrogênio líquido e radiação cósmica de fundo