Regulation of the functions of human leukocytes by oxametacine

Non steroidal anti-inflammatory drugs, such as oxametacine, are generally used in treatment of rheumatoid disease. In an 'in vitro' experimental model, the drug efficacy was tested on leukocyte functions. Locomotion, both random and directional, phagocytic activity and superoxide production of normal and rheumatoid PMNL were tested in the presence of varying concentrations of oxometacine. Locomotion was evaluated by using modified Boyden chambers; phagocytosis was tested by number of yeast particles injested and by NBT reduction; superoxide production was assayed by reduction of ferricytochrome C. In our conditions the drug exhibited a strong anti-inflammatory effect. In fact, chemotaxis and anion production were specifically depressed in a dose-dependent way.     

Preparation of soybean seed samples for FT-IR microspectroscopy

Typical preparation of seed samples for infrared (IR) microspectroscopy involves imbibition of the seed for varying time periods followed by cryosectioning. Imbibition, however, may initiate germination even at 4° C with associated changes in the chemistry of the sample. We have found that it is possible to section seeds that are sufficiently hard, such as soybeans, on a standard laboratory microtome without imbibition. The use of dry sectioning of unimbibed seeds is reported here, as well as a comparison of different mounting media and modes of analysis. Glycerol, Tissue-Tek, and ethanol were used as mounting media, and the quality of the resulting spectra was assessed. Ethanol was the preferred mountant, because it dried quickly with no residue and thus did not interfere with the spectrum of interest. Analysis in transmission mode using barium fluoride windows to hold the samples was compared with transmission-reflection analysis with sections mounted on special infrared-reflecting slides. The two modes of analysis performed well in different regions of the spectrum. The mode of analysis (transmission vs. transmission-reflection) should be based on the components of greatest interest in the sample.     

Anti-tumor therapy with macroencapsulated endostatin producer cells

Background  

Theracyte is a polytetrafluoroethylene membrane macroencapsulation system designed to induce neovascularization at the tissue interface, protecting the cells from host's immune rejection, thereby circumventing the problem of limited half-life and variation in circulating levels. Endostatin is a potent inhibitor of angiogenesis and tumor growth. Continuous delivery of endostatin improves the efficacy and potency of the antitumoral therapy. The purpose of this study was to determine whether recombinant fibroblasts expressing endostatin encapsulated in Theracyte immunoisolation devices can be used for delivery of this therapeutic protein for treatment of mice bearing B16F10 melanoma and Ehrlich tumors.     

Near–infrared photodynamic inactivation of S. pneumoniae and its interaction with RAW 264.7 macrophages

Pneumonia is the main cause of children mortality worldwide, and its major treatment obstacle stems from the microorganisms increasing development of resistance to several antibiotics. Photodynamic therapy has been presenting, for the last decades, promising results for some subtypes of cancer and infections. In this work we aimed to develop a safe and efficient in vitro protocol for photodynamic inactivation of Streptococcus pneumoniae, one of the most commonly found bacteria in pneumonia cases, using two near‐infrared light sources and indocyanine green, a FDA approved dye. Photodynamic inactivation experiments with bacteria alone allowed to determine the best parameters for microbial inactivation. Cytotoxicity assays with RAW 264.7 macrophages evaluated the safety of the PDI. To determine if the photodynamic inactivation had a positive or negative effect on the natural killing action of macrophages, we selected and tested fewer indocyanine green concentrations and 10 J/cm² on macrophage‐S. pneumoniae co‐cultures. We concluded that ICG has potential as a photosensitizer for near‐infrared photodynamic inactivation of S. pneumoniae, producing minimum negative impact on RAW 264.7 macrophages and having a positive interaction with the immune cell's microbicidal action.

     

Single-nucleotide polymorphism,linkage disequilibrium and geographic structure in the malaria parasite <Emphasis Type="Italic">Plasmodium vivax</Emphasis>: prospects for genome-wide association studies

Background

The ideal malaria parasite populations for initial mapping of genomic regions contributing to phenotypes such as drug resistance and virulence, through genome-wide association studies, are those with high genetic diversity, allowing for numerous informative markers, and rare meiotic recombination, allowing for strong linkage disequilibrium (LD) between markers and phenotype-determining loci. However, levels of genetic diversity and LD in field populations of the major human malaria parasite P. vivax remain little characterized.

Results

We examined single-nucleotide polymorphisms (SNPs) and LD patterns across a 100-kb chromosome segment of P. vivax in 238 field isolates from areas of low to moderate malaria endemicity in South America and Asia, where LD tends to be more extensive than in holoendemic populations, and in two monkey-adapted strains (Salvador-I, from El Salvador, and Belem, from Brazil). We found varying levels of SNP diversity and LD across populations, with the highest diversity and strongest LD in the area of lowest malaria transmission. We found several clusters of contiguous markers with rare meiotic recombination and characterized a relatively conserved haplotype structure among populations, suggesting the existence of recombination hotspots in the genome region analyzed. Both silent and nonsynonymous SNPs revealed substantial between-population differentiation, which accounted for ~40% of the overall genetic diversity observed. Although parasites clustered according to their continental origin, we found evidence for substructure within the Brazilian population of P. vivax. We also explored between-population differentiation patterns revealed by loci putatively affected by natural selection and found marked geographic variation in frequencies of nucleotide substitutions at the pvmdr-1 locus, putatively associated with drug resistance.

Conclusion

These findings support the feasibility of genome-wide association studies in carefully selected populations of P. vivax, using relatively low densities of markers, but underscore the risk of false positives caused by population structure at both local and regional levels.See commentary: http://www.biomedcentral.com/1741-7007/8/90

     

Age determination in human adults by dental histology

Dentine root transparency (RDT) has been measured on 70 histological sections of teeth from 46 individuals of known sex and age. In order to obtain the estimates of individual chronological age, Bang & Ramm (1970) equations have been applied to the value obtained by the measurements. Using the percentage ratio hx100/H (after Lemendin & Cambray 1981)--were h is the extension of the root transparency zone (in mm) and H is the total root length (in mm), some regression functions have been elaborated. The error of the age estimates obtained following Bang & Ramm was quite high in percentage, being comprised between +/- 5 years only in 21.13% of the cases.     

A xyloglucan-specific endo-beta-1,4-glucanase from Aspergillus aculeatus: expression cloning in yeast, purification and characterization of the recombinant enzyme

A full-length c-DNA encoding a xyloglucan-specific endo -beta-1, 4- glucanase (XEG) has been isolated from the filamentous fungus Aspergillus aculeatus by expression cloning in yeast. The colonies expressing functional XEG were identified on agar plates containing azurine-dyed cross-linked xyloglucan. The cDNA encoding XEG was isolated, sequenced, cloned into an Aspergillus expression vector, and transformed into Aspergillus oryzae for heterologous expression. The recombinant enzyme was purified to apparent homogeneity by anion- exchange and gel permeation chromatography. The recombinant XEG has a molecular mass of 23,600, an isoelectric point of 3.4, and is optimally stable at a pH of 3.4 and temperature below 30 degreesC. The enzyme hydrolyzes structurally diverse xyloglucans from various sources, but hydrolyzes no other cell wall component and can therefore be considered a xyloglucan-specific endo -beta-1, 4-glucanohydrolase. XEG hydrolyzes its substrates with retention of the anomeric configuration. The Kmof the recombinant enzyme is 3.6 mg/ml, and its specific activity is 260 micromol/min per mg protein. The enzyme was tested for its ability to solubilize xyloglucan oligosaccharides from plant cell walls. It was shown that treatment of plant cell walls with XEG yields only xyloglucan oligosaccharides, indicating that this enzyme can be a powerful tool in the structural elucidation of xyloglucans.