Human papillomavirus in oral squamous cells carcinoma in a population of 75 Brazilian patients

Purpose In the present study, we investigated the presence of human papillomavirus (HPV) DNA and viral types in 75 cases of oral squamous cells carcinoma from Brazil to obtain data that would contribute to a better understanding of the role of HPV in the pathogenesis of this tumor. Materials and methods DNA was extracted from paraffin-embedded tissue and amplified by polymerase chain reaction using a pair of primers designated PCO3+ and PCO4+ for the detection of a fragment of the human β-globin gene, followed by polymerase chain reaction for the detection of HPV DNA using a pair of generic primers, GP5+ and GP6+. Viral typing was performed by dot blot hybridization. Results Human papillomavirus DNA was detected in 18 (24%) of the 75 cases positive for the human β-globin gene. No significant association was observed between HPV and age, sex, or anatomical location of the tumor. The most prevalent viral type was HPV-18 (77,8%). Conclusion The low frequency of detection of HPV DNA in oral epidermoid carcinomas suggests a possible participation of the virus in the development and progression of only a subgroup of these tumors

Direct reprogramming of adult human somatic stem cells into functional neurons using Sox2, Ascl1, and Neurog2

Reprogramming of somatic cells into induced pluripotent stem cells (iPS) or directly into cells from a different lineage, including neurons, has revolutionized research in regenerative medicine in recent years. Mesenchymal stem cells are good candidates for lineage reprogramming and autologous transplantation, since they can be easily isolated from accessible sources in adult humans, such as bone marrow and dental tissues. Here, we demonstrate that expression of the transcription factors (TFs) SRY (sex determining region Y)-box 2 (Sox2), Mammalian achaete-scute homolog 1 (Ascl1), or Neurogenin 2 (Neurog2) is sufficient for reprogramming human umbilical cord mesenchymal stem cells (hUCMSC) into induced neurons (iNs). Furthermore, the combination of Sox2/Ascl1 or Sox2/Neurog2 is sufficient to reprogram up to 50% of transfected hUCMSCs into iNs showing electrical properties of mature neurons and establishing synaptic contacts with co-culture primary neurons. Finally, we show evidence supporting the notion that different combinations of TFs (Sox2/Ascl1 and Sox2/Neurog2) may induce multiple and overlapping neuronal phenotypes in lineage-reprogrammed iNs, suggesting that neuronal fate is determined by a combination of signals involving the TFs used for reprogramming but also the internal state of the converted cell. Altogether, the data presented here contribute to the advancement of techniques aiming at obtaining specific neuronal phenotypes from lineage-converted human somatic cells to treat neurological disorders

Cashew nut roasting: chemical characterization of particulate matter\ud and genotocixity analysis

Background: Particulate matter (PM) potentially harmful to health and related to genotoxic events, an increase in the number of hospitalizations and mortality from respiratory and cardiovascular diseases.\ud The present study conducted the first characterization of elemental composition and polycyclic aromatic hydrocarbon (PAH) analysis of PM, as well as the biomonitoring of genotoxic activity associated to artesanal cashew nut roasting, an importante economic and social activity worldwide.\ud Methods: The levels of PM2.5 and black carbon were also measured by gravimetric analysis and light reflectance. The elementa lcomposition was determined using X-ray fluorescence spectrometry and PAH analysis was carried out by gás chromatography–mass spectrometry. Genotoxic activity was measured by the Tradescantia pallida micronucleus bioassay (Trad-MCN).Other biomarkers of DNA damage, such as núcleoplasmic bridges and nuclear fragments, were also quantified. Results: The mean amount of PM2.5 accumulated in the filters (January 2124.2 mg/m3; May 1022.2 mg/m3;\ud September 1291.9 mg/m3), black carbon(January 363.6 mg/m3; May70 mg/m3; September 69.4 mg/m3) and concentrations of Al, Si, P, S, Cl, K, Ca ,Ti,Cr, Mn, Fe, Ni, Cu, Zn, Se, Br and Pb were significantly higher than the non-exposed area. Biomass burning tracers K,Cl, and S were the major inorganic compounds found. Benzo[k]fluoranthene, indene[1,2,3-c,d]pyrene, benzo[ghi]perylene, phenanthrene and benzo[b]fluor-\ud anthene were the most abundant PAHs. Mean benzo[a]pyrene-equivalent carcinogenic power values showed a significant câncer risk. The Trad-MCN bioassay revealed an increase in micronucleus frequency, 2–7 times higher than the negative control and significantly higher in all the months analyzed, possibly related to the mutagenic PAHs found.\ud Conclusions: This study demonstrated that artesanal cashew nut roasting is a serious occupational problem, with harmful effects on workers' health. Those involved in this activity are exposed to higher PM2.5 concentrations and to 12 PAHs considered potentially mutagenic and/or carcinogenic. The Trad-MCN with T. pallida was sensitive and efficient in evaluating the genotoxicity of the components and other nuclear alterations may be used as effective biomarkers of DNA damage.CNPq - 555223/2006-

Micronucleus frequency in children exposed to biomass burning in the Brazilian Legal Amazon region: a control case study

<p>Abstract</p> <p>Background</p> <p>The Amazon represents an area of 61% of Brazilian territory and is undergoing major changes resulting from disorderly economic development, especially the advance of agribusiness. Composition of the atmosphere is controlled by several natural and anthropogenic processes, and emission from biomass burning is one with the major impact on human health. The aim of this study was to evaluate genotoxic potential of air pollutants generated by biomass burning through micronucleus assay in exfoliated buccal cells of schoolchildren in the Brazilian Amazon region.</p> <p>Methods</p> <p>The study was conducted during the dry seasons in two regions of the Brazilian Amazon. The assay was carried out on buccal epithelial cells of 574 schoolchildren between 6-16 years old.</p> <p>Results</p> <p>The results show a significant difference between micronucleus frequencies in children exposed to biomass burning compared to those in a control area.</p> <p>Conclusions</p> <p>The present study demonstrated that in situ biomonitoring using a sensitive and low cost assay (buccal micronucleus assay) may be an important tool for monitoring air quality in remote regions. It is difficult to attribute the increase in micronuclei frequency observed in our study to any specific toxic element integrated in the particulate matters. However, the contribution of the present study lies in the evidence that increased exposure to fine particulate matter generates an increased micronuclei frequency in oral epithelial cells of schoolchildren.</p

Genotoxic potential generated by biomass burning in the Brazilian Legal Amazon by Tradescantia micronucleus bioassay: a toxicity assessment study

<p>Abstract</p> <p>Background</p> <p>The Brazilian Amazon has suffered impacts from non-sustainable economic development, especially owing to the expansion of agricultural commodities into forest areas. The Tangará da Serra region, located in the southern of the Legal Amazon, is characterized by non-mechanized sugar cane production. In addition, it lies on the dispersion path of the pollution plume generated by biomass burning. The aim of this study was to assess the genotoxic potential of the atmosphere in the Tangará da Serra region, using <it>Tradescantia pallida </it>as <it>in situ </it>bioindicator.</p> <p>Methods</p> <p>The study was conducted during the dry and rainy seasons, where the plants were exposed to two types of exposure, active and passive.</p> <p>Results</p> <p>The results showed that in all the sampling seasons, irrespective of exposure type, there was an increase in micronucleus frequency, compared to control and that it was statistically significant in the dry season. A strong and significant relationship was also observed between the increase in micronucleus incidence and the rise in fine particulate matter, and hospital morbidity from respiratory diseases in children.</p> <p>Conclusions</p> <p>Based on the results, we demonstrated that pollutants generated by biomass burning in the Brazilian Amazon can induce genetic damage in test plants that was more prominent during dry season, and correlated with the level of particulates and elevated respiratory morbidity.</p

The complete genome sequence of Chromobacterium violaceum reveals remarkable and exploitable bacterial adaptability

Chromobacterium violaceum is one of millions of species of free-living microorganisms that populate the soil and water in the extant areas of tropical biodiversity around the world. Its complete genome sequence reveals (i) extensive alternative pathways for energy generation, (ii) ≈500 ORFs for transport-related proteins, (iii) complex and extensive systems for stress adaptation and motility, and (iv) wide-spread utilization of quorum sensing for control of inducible systems, all of which underpin the versatility and adaptability of the organism. The genome also contains extensive but incomplete arrays of ORFs coding for proteins associated with mammalian pathogenicity, possibly involved in the occasional but often fatal cases of human C. violaceum infection. There is, in addition, a series of previously unknown but important enzymes and secondary metabolites including paraquat-inducible proteins, drug and heavy-metal-resistance proteins, multiple chitinases, and proteins for the detoxification of xenobiotics that may have biotechnological applications