160 research outputs found
Aberrant p15, p16, p53, and DAPK Gene Methylation in Myelomagenesis: Clinical and Prognostic Implications
BACKGROUND:
Aberrant DNA methylation is considered a crucial mechanism in the pathogenesis of monoclonal gammopathies. We aimed to investigate the contribution of hypermethylation of 4 tumor suppressor genes to the multistep process of myelomagenesis.
METHODS:
The methylation status of p15, p16, p53, and DAPK genes was evaluated in bone marrow samples from 94 patients at diagnosis: monoclonal gammopathy of uncertain significance (MGUS) (n = 48), smoldering multiple myeloma (SMM) (n = 8) and symptomatic multiple myeloma (MM) (n = 38), and from 8 healthy controls by methylation-specific polymerase chain reaction analysis.
RESULTS:
Overall, 63% of patients with MM and 39% of patients with MGUS presented at least 1 hypermethylated gene (P < .05). No aberrant methylation was detected in normal bone marrow. The frequency of methylation for individual genes in patients with MGUS, SMM, and MM was p15, 15%, 50%, 21%; p16, 15%, 13%, 32%; p53, 2%, 12,5%, 5%, and DAPK, 19%, 25%, 39%, respectively (P < .05). No correlation was found between aberrant methylation and immunophenotypic markers, cytogenetic features, progression-free survival, and overall survival in patients with MM.
CONCLUSIONS:
The current study supports a relevant role for p15, p16, and DAPK hypermethylation in the genesis of the plasma cell neoplasm. DAPK hypermethylation also might be an important step in the progression from MGUS to MM.info:eu-repo/semantics/publishedVersio
Use of construction and demolition recycled materials (C&Drm) in road pavements validated on experimental test sections
The construction activity usually generates large amounts of waste from different sources and processes. Due to the increasing shortage of space for landfill implementation and the costs associated with waste control regulations, derived from its ever increasing environmental protection requirements, the most desirable alternative is the reduction of construction and demolition waste volumes by means of their reuse and recycling. A research project, SUPREMA - Sustainable Application of Construction and Demolition Recycled Materials (C&DRM) in Road Infrastructures, is being developed by the National Laboratory for Civil Engineering (LNEC), and by the University of Lisbon (IST). This project seeks to contribute to the sustainable implementation of C&DRM in road pavements by improving the knowledge of the physical, mechanical and environmental behaviour of these materials when placed as aggregates in unbound pavement layers. Besides a general presentation of the research project and the construction procedures of a test pit structure where four different materials were applied, this paper presents some results related to the characteristics of the studied materials, supported by laboratory and by in situ tests performed with the FWD in the test pit structure. It was concluded that all materials demonstrate an acceptable structural performance
Vaccines against toxoplasma gondii : challenges and opportunities
Development of vaccines against Toxoplasma gondii infection in humans is of high priority, given the high burden of disease in some areas of the world like South America, and the lack of effective drugs with few adverse effects. Rodent models have been used in research on vaccines against T. gondii over the past decades. However, regardless of the vaccine construct, the vaccines have not been able to induce protective immunity when the organism is challenged with T. gondii, either directly or via a vector. Only a few live, attenuated T. gondii strains used for immunization have been able to confer protective immunity, which is measured by a lack of tissue cysts after challenge. Furthermore, challenge with low virulence strains, especially strains with genotype II, will probably be insufficient to provide protection against the more virulent T. gondii strains, such as those with genotypes I or II, or those genotypes from South America not belonging to genotype I, II or III. Future studies should use animal models besides rodents, and challenges should be performed with at least one genotype II T. gondii and one of the more virulent genotypes. Endpoints like maternal-foetal transmission and prevention of eye disease are important in addition to the traditional endpoint of survival or reduction in numbers of brain cysts after challenge
Expanding the knowledge about Leishmania species in wild mammals and dogs in the Brazilian savannah
Background: Wild, synanthropic and domestic mammals act as hosts and/or reservoirs of several Leishmania spp. Studies on possible reservoirs of Leishmania in different areas are fundamental to understand host-parasite interactions and develop strategies for the surveillance and control of leishmaniasis. In the present study, we evaluated the Leishmania spp. occurrence in mammals in two conservation units and their surroundings in BrasÃlia, Federal District (FD), Brazil. Methods: Small mammals were captured in BrasÃlia National Park (BNP) and Contagem Biological Reserve (CBR) and
dogs were sampled in residential areas in their vicinity. Skin and blood samples were evaluated by PCR using different molecular markers (D7 24Sα rRNA and rDNA ITS1). Leishmania species were identified by sequencing of PCR products. Dog blood samples were subjected to the rapid immunochromatographic test (DPP) for detection of anti-Leishmania infantum antibodies. Results: 179 wild mammals were studied and 20.1% had Leishmania DNA successfully detected in at least one sample. Six mammal species were considered infected: Clyomys laticeps, Necromys lasiurus, Nectomys rattus, Rhipidomys macrurus, Didelphis albiventris and Gracilinanus agilis. No significant difference, comparing the proportion of individuals with Leishmania spp., was observed between the sampled areas and wild mammal species. Most of the positive samples were collected from the rodent N. lasiurus, infected by L. amazonensis or L. braziliensis. Moreover, infections by Trypanosoma spp. were detected in N. lasiurus and G. agilis. All 19 dog samples were positive by DPP; however, only three (15.8%) were confirmed by PCR assays. DNA sequences of ITS1 dog amplicons showed 100% identity with L. infantum sequence. Conclusions: The results suggest the participation of six species of wild mammals in the enzootic transmission of Leishmania spp. in FD. This is the first report of L. amazonensis in N. lasiurus
Primary versus secondary source of data in observational studies and heterogeneity in meta-analyses of drug effects: a survey of major medical journals
The data from individual observational studies included in meta-analyses of drug effects are collected either from ad hoc methods (i.e. "primary data") or databases that were established for non-research purposes (i.e. "secondary data"). The use of secondary sources may be prone to measurement bias and confounding due to over-the-counter and out-of-pocket drug consumption, or non-adherence to treatment. In fact, it has been noted that failing to consider the origin of the data as a potential cause of heterogeneity may change the conclusions of a meta-analysis. We aimed to assess to what extent the origin of data is explored as a source of heterogeneity in meta-analyses of observational studies.publishe
Linking Hydrothermal Geochemistry to Organismal Physiology: Physiological Versatility in Riftia pachyptila from Sedimented and Basalt-hosted Vents
Much of what is known regarding Riftia pachyptila physiology is based on the wealth of studies of tubeworms living at diffuse flows along the fast-spreading, basalt-hosted East Pacific Rise (EPR). These studies have collectively suggested that Riftia pachyptila and its chemoautotrophic symbionts are physiologically specialized, highly productive associations relying on hydrogen sulfide and oxygen to generate energy for carbon fixation, and the symbiont's nitrate reduction to ammonia for energy and biosynthesis. However, Riftia also flourish in sediment-hosted vents, which are markedly different in geochemistry than basalt-hosted systems. Here we present data from shipboard physiological studies and global quantitative proteomic analyses of Riftia pachyptila trophosome tissue recovered from tubeworms residing in the EPR and the Guaymas basin, a sedimented, hydrothermal vent field. We observed marked differences in symbiont nitrogen metabolism in both the respirometric and proteomic data. The proteomic data further suggest that Riftia associations in Guaymas may utilize different sulfur compounds for energy generation, may have an increased capacity for energy storage, and may play a role in degrading exogenous organic carbon. Together these data reveal that Riftia symbionts are far more physiologically plastic than previously considered, and that -contrary to previous assertions- Riftia do assimilate reduced nitrogen in some habitats. These observations raise new hypotheses regarding adaptations to the geochemical diversity of habitats occupied by Riftia, and the degree to which the environment influences symbiont physiology and evolution
Inhibition of IL-10 Production by Maternal Antibodies against Group B Streptococcus GAPDH Confers Immunity to Offspring by Favoring Neutrophil Recruitment
Group B Streptococcus (GBS) is the leading cause of neonatal pneumonia, septicemia, and meningitis. We have previously shown that in adult mice GBS glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is an extracellular virulence factor that induces production of the immunosuppressive cytokine interleukin-10 (IL-10) by the host early upon bacterial infection. Here, we investigate whether immunity to neonatal GBS infection could be achieved through maternal vaccination against bacterial GAPDH. Female BALB/c mice were immunized with rGAPDH and the progeny was infected with a lethal inoculum of GBS strains. Neonatal mice born from mothers immunized with rGAPDH were protected against infection with GBS strains, including the ST-17 highly virulent clone. A similar protective effect was observed in newborns passively immunized with anti-rGAPDH IgG antibodies, or F(ab')2 fragments, indicating that protection achieved with rGAPDH vaccination is independent of opsonophagocytic killing of bacteria. Protection against lethal GBS infection through rGAPDH maternal vaccination was due to neutralization of IL-10 production soon after infection. Consequently, IL-10 deficient (IL-10−/−) mice pups were as resistant to GBS infection as pups born from vaccinated mothers. We observed that protection was correlated with increased neutrophil trafficking to infected organs. Thus, anti-rGAPDH or anti-IL-10R treatment of mice pups before GBS infection resulted in increased neutrophil numbers and lower bacterial load in infected organs, as compared to newborn mice treated with the respective control antibodies. We showed that mothers immunized with rGAPDH produce neutralizing antibodies that are sufficient to decrease IL-10 production and induce neutrophil recruitment into infected tissues in newborn mice. These results uncover a novel mechanism for GBS virulence in a neonatal host that could be neutralized by vaccination or immunotherapy. As GBS GAPDH is a structurally conserved enzyme that is metabolically essential for bacterial growth in media containing glucose as the sole carbon source (i.e., the blood), this protein constitutes a powerful candidate for the development of a human vaccine against this pathogen
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