70 research outputs found

    Blood management in intensive care medicine: CRIT and ABC – what can we learn?

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    In 284 US intensive care units the CRIT study (Anemia and blood transfusion in the critically ill – Current clinical practice in the United States) assessed allogeneic red blood cell (RBC) transfusion and outcome in 4892 patients. As in the former European ABC study (Anemia and blood transfusion in the critically ill), the mean pretransfusion hemoglobin was approximately 8.5 g/dl and RBC transfusions were independently associated with an increased mortality. These studies were purely observational and, therefore, despite the finest statistical models indicating that RBC transfusions were independently associated with a higher mortality, it remains possible that this adverse outcome is not due to a harmful effect of RBC transfusion in itself, but merely reflects the fact that transfused patients were sicker to start with. The definitive call is still out, but one mechanism by which RBC transfusion might be harmful now appears less likely; namely, storage lesion. In the CRIT study, mortality was not increased in patients receiving 'old' RBCs (>14 days stored) versus 'fresh' RBCs. The effect of leukoreduction could not be assessed since mainly nonleukoreduced RBCs were transfused. The evidence is mounting, however, that RBC transfusions are efficacious only when oxygen delivery is compromised. What can be done to diminish the use of RBC transfusions, its costs and side effects in intensive care medicine? There are two important options available today: decreasing blood loss for diagnostic purposes using pediatric sampling tubes, and establishing restrictive multidisciplinary transfusion guidelines and implementing them in daily clinical practice

    Allogeneic blood transfusions: benefit, risks and clinical indications in countries with a low or high human development index

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    The risks associated with allogeneic red blood cell (RBC) transfusions differ significantly between countries with low and high human development indexes (HDIs). In countries with a low HDI, the risk of infection (HIV, HBV, HCV and malaria) is elevated. In contrast, in countries with a high HDI, immunological reactions (haemolytic transfusion reactions, alloimmunization and immunosuppression) are predominant. Therefore the overall risk associated with RBC transfusions in low HDI countries is much more significant than that in high HDI countries. In view of these risks, the limited efficacy of RBC transfusion and its high costs, this procedure should be used sparingly and rationally. Therefore RBC transfusion protocols adapted to the local situation are essential. Such protocols should distinguish between physiological and haemoglobin-based transfusion triggers. In countries with a high HDI, relative tachycardia and hypotension, despite normovolaemia, ST-segment changes suggestive of myocardial ischaemia and an Hb level 80 years and those with coronary artery or cerebrovascular disease. In countries with a low HDI, clinical signs of circulatory failure or myocardial ischaemia and an Hb level <5 g/dl can serve as transfusion guideline

    Prym varieties of double coverings of elliptic curves

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    We prove the generic injectivity of the Prym map P:R1,rAr2δ\mathscr{P}: \mathcal{R}_{1, r} \rightarrow \mathcal{A}_{\frac{r}{2}}^\delta sending a double covering of an elliptic curve ramified at r6r \geq 6 points to its polarized Prym variety. For r=6r=6 the map is birational and both R1,6\mathcal{R}_{1,6} and A3δ\mathcal{A}_3^\delta are unirational

    Isogenies of Jacobians

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    By studying the infinitesimal variations of the Hodge structure and a generalization of the classical Babbage-Enriques-Petri theorem, we prove that the Jacobian variety of a generic element of a codimension k subvariety of Mg is not isogenous to different Jacobian if g > 3k + 4. We extend this result to k = 1, g > 5 by using degeneration methods

    Antiproliferative effects of Tubi-bee propolis in glioblastoma cell lines

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    Propolis is a resin formed by a complex chemical composition of substances that bees collect from plants. Since ancient times, propolis has been used in folk medicine, due to its biological properties, that include antimicrobial, anti-inflammatory, antitumoral and immunomodulatory activities. Glioblastoma is the most common human brain tumor. Despite the improvements in GBM standard treatment, patients’ prognosis is still very poor. The aim of this work was to evaluate in vitro the Tubi-bee propolis effects on human glioblastoma (U251 and U343) and fibroblast (MRC-5) cell lines. Proliferation, clonogenic capacity and apoptosis were analyzed after treatment with 1 mg/mL and 2 mg/mL propolis concentrations for different time periods. Additionally, glioblastoma cell lines were submitted to treatment with propolis combined with temozolomide (TMZ). Data showed an antiproliferative effect of tubi-bee propolis against glioblastoma and fibroblast cell lines. Combination of propolis with TMZ had a synergic anti-proliferative effect. Moreover, propolis caused decrease in colony formation in glioblastoma cell lines. Propolis treatment had no effects on apoptosis, demonstrating a cytostatic action. Further investigations are needed to elucidate the molecular mechanism of the antitumor effect of propolis, and the study of its individual components may reveal specific molecules with antiproliferative capacity

    Effect of propolis gel on the in vitro reduction of dentin permeability

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    OBJECTIVE: The aim of this study was to evaluate the capacity of potassium oxalate, fluoride gel and two kinds of propolis gel to reduce the hydraulic conductance of dentin, in vitro. MATERIAL AND METHODS: The methodology used for the measurement of hydraulic conductance of dentin in the present study was based on a model proposed in literature. Thirty-six 1-mm-thick dentin discs, obtained from extracted human third molars were divided into 4 groups (n=9). The groups corresponded to the following experimental materials: GI-10% propolis gel, pH 4.1; GII-30% propolis gel; GIII-3% potassium oxalate gel, pH 4,1; and GIV-1.23% fluoride gel, pH 4.1, applied to the dentin under the following surface conditions: after 37% phosphoric acid and before 6% citric acid application. The occluding capacity of the dentin tubules was evaluated using scanning electron microscopy (SEM) at ×500, ×1,000 and ×2,000 magnifications. Data were analyzed statistically by two-way ANOVA and Tukey's test at 5% significance level. RESULTS: Groups I, II, III, IV did not differ significantly from the others in any conditions by reducing in hydraulic conductance. The active agents reduced dentin permeability; however they produced the smallest reduction in hydraulic conductance when compared to the presence of smear layer (P<0.05). The effectiveness in reducing dentin permeability did not differ significantly from 10% or 30% propolis gels. SEM micrographs revealed that dentin tubules were partially occluded after treatment with propolis. CONCLUSIONS: Under the conditions of this study, the application of 10% and 30% propolis gels did not seem to reduce the hydraulic conductance of dentin in vitro, but it showed capacity of partially obliterating the dentin tubules. Propolis is used in the treatment of different oral problems without causing significant great collateral effects, and can be a good option in the treatment of patients with dentin sensitivity
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