UV-Induced Structural Changes of Model DNA Helices Probed by Optical Spectroscopy

International audienceChemical alterations of DNA, if not repaired, may lead to carcinogenic mutations. Structural modifications of the helix around the lesion enable its recognition by repair enzymes. We have used absorption spectroscopy and mass spectrometry to detect structural changes provoked by cyclobutane thymine dimers, the major lesion induced by UV radiation. We found that formation of a cyclobutane dimer in the model duplex (dA)20 · (dT)20 destroys base stacking on the adenine strand. The physical background of this novel approach is the existence of charge-transfer states among neighboring bases, whose contribution to the hypochromism of the helix disappears following destacking

Effect of treatment with hcl/alcoholic in the modification of corn starch.

Corn is the cereal most produced in the world. Corn starches were modified by HCl 0.1 mol L-1 in alcoholic and aqueous solutions. Three mass losses can be observed in the degradation process using TG-DTG curve. The native and treated starches samples don't show differences in the stability region. With DSC curves were observed lower values of the ΔH of gelatinization of the modified starch by HCl in the alcoholic solutions. The modifications using alcoholic solutions demonstrated a good alternative to obtain modifies starches.Edição dos Anais do 7º Simpósio de Análise Térmica, 2015, Bauru

Singlet excited state dynamics of uracil and thymine derivatives: A femtosecond fluorescence upconversion study in acetonitrile

The excited state properties of uracil, thymine and four analogous uracil compounds have been studied in acetonitrile by steady-state and time-resolved spectroscopy. The excited state lifetimes were measured using femtosecond UV fluorescence upconversion. The excited state lifetimes of uracil and its 1- and 3-methyl substituted derivatives are well described by one ultrafast (6100 fs) component. Five substituted compounds show a more complex behavior, exhibiting longer excited state lifetimes and bi-exponential fluorescence decays. These longer decays are substantially faster in acetonitrile than in aqueous solution showing that the excited state deactivation mechanism is in part governed by the solvent

Thermal analysis of byproducts from fast-pyrolysis of Eucalyptus flour.

Fast pyrolysis is the thermal decomposition of biomass in the absence of oxygen. This study aims to evaluate thermal analysis of byproducts from fast-pyrolysis of Eucalyptus wood fines. The pyrolysis was conducted in a pilot-scale at 500°C and 100 mm H2O. Charcoal from this process showed high ash content (over than 20%) and incomplete carbonization. Aqueous extract and bio-oil showed similar thermal decomposition events. However, mass percentage decomposed at each temperature was different between these samples.Edição dos Anais do 7º Simpósio de Análise Térmica, 2015, Bauru

JAK-2 inhibitors and allogeneic transplant in myelofibrosis

7The activation of the JAK1/JAK2 pathway plays a crucial role in the pathogenesis of myelofibrosis. Treatment with the JAK2 inhibitor ruxolitinib demonstrated to reduce splenomegaly and symptoms in patients affected by myelofibrosis, leading to a significant improvement of overall survival in comparison with the supportive therapies. Taking in account this recent therapeutic progress, it is necessary to redefine the role of the allogeneic hematopoietic stem cell transplantation, which has been considered the only curative option for fit myelofibrosis patients up to now. In the era of JAK2 inhibitors, allogeneic transplant is still indicated in patients with intermediate-2 and high-risk myelofibrosis or red blood cell transfusion dependent patients or patients with unfavourable karyotype. There is no direct evidence to recommend which conditioning regimen should be preferentially adopted. Graft failure, relapse and transplant related mortality are still current issues of the allogeneic stem cell transplantation, particularly from unrelated donors. Ruxolitinib can be efficaciously included in the platform of allogeneic transplant. In fact, ruxolitinib treatment for 3-4 months before transplant has demonstrated to reduce spleen and improve performance status in about 30-50% of patients, without impairing the outcome of the subsequent transplant. Ruxolitinib has to stopped the day before conditioning to avoid rebound phenomenon. There are no sufficient data to recommend ruxolitinib administration after transplant with the aim of eradicating minimal residual disease and preventing relapse.openopenPatriarca, F; Sperotto, A; De Marchi, R; Perali, G; Cigana, C; Lazzarotto, D; Fanin, RPatriarca, Francesca; Sperotto, A; De Marchi, R; Perali, G; Cigana, C; Lazzarotto, D; Fanin, Renat

Caracterização térmica e comparação da composição de óleos essenciais provenientes de folhas secas e frescas de eucalipto.

O óleo essencial de eucalipto possui amplo espectro de utilização no mercado atual. O inseto psilídeo (Glycaspis brimblecombei) tem sido alvo de muitos estudos recentes, uma vez que o dano causado ao plantio de eucalipto pode inviabilizar o uso. Em estudo anterior realizado por nosso grupo de pesquisa, relacionamos a resistência dos eucaliptos com as características térmicas de seus óleos essenciais extraídos das folhas secas. O presente trabalho tem como objetivo comparar a composição de óleos essenciais de eucaliptos provenientes de folhas frescas e secas, tendo em vista que o psilídeo ataca as folhas frescas de eucaliptos. Para isso foram extraídos óleos essenciais de folhas frescas e secas de três espécies de eucaliptos e realizada análise de TG-DTA. Para ambas espécies foi comum a perda de massa em temperatura menor para os óleos essencias de folhas secas, e curvas DTA com diferentes perfis, o que demostra uma composição química diferente para os óleos essenciais das folhas frescas e secas. Estudos adicionais são necessários para caracterização e identificação dos compostos presentes nestes óleos essenciais

Avaliação termoanalítica de óleos essenciais de Eucalyptus spp suscetíveis e resistentes ao psilideo-de-concha.

O Glycaspis brimblecombei é uma praga florestal que ataca diversas espécies de eucalipto. Os terpenos e monoterpenos são os principais constituintes dos óleos essenciais do eucalipto. Amostras de óleos essenciais foram extraídas de folhas trituradas de eucaliptos resistentes e suscetíveis a este inseto. Os óleos foram analisados pelas técnicas termoanalíticas e observados comportamentos diferentes para os extraídos de eucaliptos resistentes e suscetíveis. Mais estudos são necessários para determinar as composições.Edição dos Anais do 7º Simpósio de Análise Térmica, 2015, Bauru

Population pharmacokinetics and pharmacodynamic target attainment of isavuconazole against aspergillus fumigatus and aspergillus flavus in adult patients with invasive fungal diseases: Should therapeutic drug monitoring for isavuconazole be considered as mandatory as for the other mold-active azoles?

Isavuconazole is a newer broad-spectrum triazole approved for the treatment of invasive fungal disease. The objective of this study was to conduct a population pharmacokinetic and pharma-codynamic analysis of isavuconazole in a retrospective cohort of hospitalized patients. A nonlinear mixed-effect approach with Monte Carlo simulations was conducted to assess the probability of target attainment (PTA) of an area under the concentration–time curve (AUC24 h )/minimum inhibitory concentration (MIC) ratio of 33.4 (defined as efficacy threshold against A. fumigatus and A. flavus) associated with a maintenance dose (MD) of 100, 200 and 300 mg daily after loading. The cumulative fraction of response (CFR) against the EUCAST MIC distributions of A. fumigatus and A. flavus was calculated as well. The proportion of trough concentrations (Ctrough ) exceeding a defined threshold of toxicity (>5.13 mg/L) was estimated. A total of 50 patients, with a median age of 61.5 years, pro-vided 199 plasma isavuconazole concentrations. Invasive pulmonary aspergillosis was the prevalent type of infection and accounted for 80% (40/50) of cases. No clinical covariates were retained by the model. With the standard MD of 200 mg daily, CFRs were always ≥90% during the first two months of treatment. The risk of Ctrough < 1.0 mg/L was around 1%, and that of Ctrough > 5.13 mg/L was 27.7 and 39.2% at 28 and 60 days, respectively, due to isavuconazole accumulation over time. Our findings suggest that TDM for isavuconazole should not be considered as mandatory as for the other mold-active azoles voriconazole and posaconazole