423 research outputs found
Qualitative and quantitative phytochemical analysis of different extracts from Thymus algeriensis aerial parts
This study was performed to evaluate the metabolite recovery from different extraction
methods applied to Thymus algeriensis aerial parts. A high-performance liquid chromatographic
method using photodiode array detector with gradient elution has been developed and validated
for the simultaneous estimation of different phenolic compounds in the extracts and in their
corresponding purified fractions. The experimental results show that microwave-assisted aqueous
extraction for 15 min at 100 C gave the most phenolics-enriched extract, reducing extraction
time without degradation effects on bioactives. Sixteen compounds were identified in this extract,
11 phenolic compounds and five flavonoids, all known for their biological activities. Color analysis
and determination of chlorophylls and carotenoids implemented the knowledge of the chemical
profile of this plant
Weekend mortality in an Italian hospital: immediate versus delayed bedside critical care treatment
Background: a number of studies highlighted increased mortality associated with hospital admissions during weekends and holidays, the so-call "weekend effect". In this retrospective study of mortality in an acute care public hospital in Italy between 2009 and 2015, we compared inpatient mortality before and after a major organizational change in 2012. The new model (Model 2) implied that the intensivist was available on call from outside the hospital during nighttime, weekends, and holidays. The previous model (Model 1) ensured the presence of the intensivist coordinating a Medical Emergency Team (MET) inside the hospital 24 h a day, 7 days a week. Methods: life status at discharge after 9298 and 8223 hospital admissions that occurred during two consecutive periods of 1185 days each (organizational Model 1 and 2), respectively, were classified into "discharged alive", "deceased during nighttime-weekends-holidays" and "deceased during daytime-weekdays". We estimated Relative Risk Ratios (RRR) for the associations between the organizational model and life status at discharge using multinomial logistic regression models adjusted for demographic and case-mix indicators, and timing of admission (nighttime-weekends-holidays vs. daytime-weekdays). Results: there were 802 and 840 deaths under Models 1 and 2, respectively. Total mortality was higher for hospital admissions under Model 2 compared to Model 1. Model 2 was associated with a significantly higher risk of death during nighttime-weekends-holidays (IRR: 1.38, 95% CI 1.20-1.59) compared to daytime-weekdays (RRR: 1.12, 95% CI 0.97-1.31) (p = 0.04). Respiratory diagnoses, in particular, acute and chronic respiratory failure (ICD 9 codes 510-519) were the leading causes of the mortality excess under Model 2. Conclusions: our data suggest that the immediate availability of an intensivist coordinating a MET 24 h, 7 days a week can result in a better prognosis of in-hospital emergencies compared to delayed consultation
Atriplex mollis desf. Aerial parts: extraction procedures, secondary metabolites and color analysis
A method using high-performance liquid chromatography coupled with a photodiode array detector was proposed for the rapid characterization of different phenolic constituents from the extracts of Atriplex mollis aerial parts. Atriplex species are known for their multiple biological activities, but no information is available in the literature about A. mollis. With the aim to firstly characterize the main secondary metabolites of this plant, so as to orient better the biological evaluation, we applied three different extraction procedures and compared the chromatographic results. Microwave-assisted extraction gave the best yield and recovery of important compounds such as gallic acid, catechin, chlorogenic acid, p-OH benzoic acid, rutin, sinapinic acid, t-ferulic acid, naringenin and benzoic acid. These constituents belong to three important chemical classes: phenolic acids, flavonoids and monoterpenes. Color evaluation and analysis of chlorophylls (a and b) and carotenoids complete the preliminary profile of this plant. From these analyses, Atriplex mollis is a source of bioactive compounds (especially rutin, t-ferulic acid and gallic acid) and could be recommended as a plant of phyto-pharmaceutical relevance, opening new perspectives on this salt-tolerant plant
A polyphenol rich extract from Solanum melongena L. DR2 peel exhibits antioxidant properties and anti-herpes simplex virus type 1 activity in vitro
DR2B and DR2C extracts, obtained by ethanolic maceration of peel from commercially
and physiologically ripe aubergine berries, were studied for the antioxidative cytoprotective
properties and anti-HSV-1 activity, in line with the evidence that several antioxidants can impair
viral replication by maintaining reducing conditions in host cells. The antioxidative cytoprotective
effects against tBOOH-induced damage were assessed in Caco2 cells, while antiviral activity was
studied in Vero cells; polyphenolic fingerprints were characterized by integrated phytochemical
methods. Results highlighted different compositions of the extracts, with chlorogenic acid and
delphinidin-3-rutinoside as the major constituents; other peculiar phytochemicals were also identified.
Both samples reduced reactive oxygen species (ROS) production and exhibited scavenging and
chelating properties. DR2C partly counteracted the tBOOH-induced cytotoxicity, with a remarkable
lowering of lactate metabolism under both normoxia and hypoxia; interestingly, it increased
intracellular GSH levels. Furthermore, DR2C inhibited the HSV-1 replication when added for
24 h after viral adsorption, as also confirmed by the reduction of many viral proteins’ expression.
Since DR2C was able to reduce NOX4 expression during HSV-1 infection, its antiviral activity may be
correlated to its antioxidant properties. Although further studies are needed to better characterize
DR2C activity, the results suggest this extract as a promising new anti-HSV-1 agent
Antiviral and antioxidant activity of a hydroalcoholic extract from Humulus lupulus L.
A hydroalcoholic extract from female inflorescences of Humulus lupulus L. (HOP extract) was evaluated for its anti-influenza activity. The ability of the extract to interfere with different phases of viral replication was assessed, as well as its effect on the intracellular redox state, being unbalanced versus the oxidative state in infected cells. The radical scavenging power, inhibition of lipoperoxidation, and ferric reducing activity were assayed as antioxidant mechanisms. A phytochemical characterization of the extract was also performed. We found that HOP extract significantly inhibited replication of various viral strains, at different time from infection. Viral replication was partly inhibited when virus was incubated with extract before infection, suggesting a direct effect on the virions. Since HOP extract was able to restore the reducing conditions of infected cells, by increasing glutathione content, its antiviral activity might be also due to an interference with redox-sensitive pathways required for viral replication. Accordingly, the extract exerted radical scavenging and reducing effects and inhibited lipoperoxidation and the tBOOH-induced cytotoxicity. At phytochemical analysis, different phenolics were identified, which altogether might contribute to HOP antiviral effect. In conclusion, our results highlighted anti-influenza and antioxidant properties of HOP extract, which encourage further in vivo studies to evaluate its possible application
Allogeneic mesenchymal stromal cells overexpressing mutant human Hypoxia-inducible factor 1-α (HIF1-α) in an ovine model of acute myocardial infarction
Background-Bone marrow mesenchymal stromal cells (BMMSCs) are cardioprotective in acute myocardial infarction (AMI) because of release of paracrine angiogenic and prosurvival factors. Hypoxia-inducible factor 1-α (HIF1-α), rapidly degraded during normoxia, is stabilized during ischemia and upregulates various cardioprotective genes. We hypothesized that BMMSCs engineered to overexpress mutant, oxygen-resistant HIF1-α would confer greater cardioprotection than nontransfected BMMSCs in sheep with AMI. Methods and Results-Allogeneic BMMSCs transfected with a minicircle vector encoding mutant HIF1-α (BMMSC-HIF) were injected in the peri-infarct of sheep (n=6) undergoing coronary occlusion. Over 2 months, infarct volume measured by cardiac magnetic resonance (CMR) imaging decreased by 71.7±1.3% (P < 0.001), and left ventricular (LV) percent ejection fraction (%EF) increased near 2-fold (P < 0.001) in the presence of markedly decreased end-systolic volume. Sheep receiving nontransfected BMMSCs (BMMSC; n=6) displayed less infarct size limitation and percent LVEF improvement, whereas in placebo-treated animals (n=6), neither parameters changed over time. HIF1-α-transfected BMMSCs (BMMSC-HIF) induced angio-/arteriogenesis and decreased apoptosis by HIF1-mediated overexpression of erythropoietin, inducible nitrous oxide synthase, vascular endothelial growth factor, and angiopoietin-1. Cell tracking using paramagnetic iron nanoparticles in 12 additional sheep revealed enhanced long-term retention of BMMSC-HIF. Conclusions-Intramyocardial delivery of BMMSC-HIF reduced infarct size and improved LV systolic performance compared to BMMSC, attributed to increased neovascularization and cardioprotective effects induced by HIF1-mediated overexpression of paracrine factors and enhanced retention of injected cells. Given the safety of the minicircle vector and the feasibility of BMMSCs for allogeneic application, this treatment may be potentially useful in the clinic.Fil: Hnatiuk, Anna. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Medicina Traslacional, Trasplante y Bioingeniería. Fundación Favaloro. Instituto de Medicina Traslacional, Trasplante y Bioingeniería; ArgentinaFil: Ong, Sang-Ging. Stanford University School of Medicine; Estados UnidosFil: Olea, Fernanda Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Medicina Traslacional, Trasplante y Bioingeniería. Fundación Favaloro. Instituto de Medicina Traslacional, Trasplante y Bioingeniería; ArgentinaFil: Locatelli, Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Medicina Traslacional, Trasplante y Bioingeniería. Fundación Favaloro. Instituto de Medicina Traslacional, Trasplante y Bioingeniería; ArgentinaFil: Riegler, Johannes. Stanford University School of Medicine; Estados UnidosFil: Lee, Won Hee. Stanford University School of Medicine; Estados UnidosFil: Jen, Cheng Hao. University of London; Reino UnidoFil: De Lorenzi, Andrea. Fundación Favaloro; ArgentinaFil: Giménez, Carlos Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Medicina Traslacional, Trasplante y Bioingeniería. Fundación Favaloro. Instituto de Medicina Traslacional, Trasplante y Bioingeniería; ArgentinaFil: Laguens, Rubén. Universidad Favaloro; ArgentinaFil: Wu, Joseph C.. Stanford University School of Medicine; Estados UnidosFil: Crottogini, Alberto José. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Medicina Traslacional, Trasplante y Bioingeniería. Fundación Favaloro. Instituto de Medicina Traslacional, Trasplante y Bioingeniería; Argentin
Preliminary evaluation of an ELISA kit for the detection of Aldosterone concentration in dog’s urine
Aldosterone is a corticosteroid hormone that plays a pivotal role in homeostatic regulation of water and salt reabsorption, blood volume and pressure. Aldosterone levels tent to rise in humans in hypertension, chronic and acute congestive heart failure (CHF); detrimental effects are opposed by drugs like ACE inhibitors and anti-mineralocorticoid. Aldosterone has a pulsatile secretion, so measurement in serum is less indicative than in urine, where concentration can be indexed to creatinine ratio for estimation of the 24-h aldosterone excretion.Few studies have evaluated aldosterone in canine urine patients, and none by ELISA. Aim of the study was to evaluate a commercial ELISA kit for measuring aldosterone in dog’s urine.Urine was collectedby free catchfrom four dogs. Two were healthy, one was affected by CHF and prescribed anti-mineralocorticoiddaily, one was affected by chronic kidney disease (CKD). Urine was centrifuged (1250g/5 min) and supernatant frozen (-20°C). Aldosterone was measured by a competitive ELISA previously validated for dogs. Twenty-four hours acid hydrolysis was performed on urinary samples before assay.The ELISA standard curve in a semi-log plot was linear between 2.5 and 3.9 ng/mL. Spike-and-recovery, linearity-of-dilution and parallelism experiments showed accuracy inmeasuring aldosterone in dog urine samples. The intra-assay coefficient of variation showed good reproducibility of the assay.Urinary samples are easy to collect, and the ELISA used in this preliminary study seems promising in determining aldosterone in dog urine. Its levels can be of great diagnostic and prognostic value for dogs affected by acute and chronic CHF, in order to assess the best therapeutic strategy. This preliminary analysis will be followed by further studies in patients affected by acute and chronic CHF
Activation of an endothelial Notch1-Jagged1 circuit induces VCAM1 expression, an effect amplified by interleukin-1β
The Notch1 and Notch4 signaling pathways regulate endothelial cell homeostasis. Inflammatory cytokines induce the expression of endothelial adhesion molecules, including VCAM1, partly by downregulating Notch4 signaling. We investigated the role of endothelial Notch1 in this IL-1β-mediated process. Brief treatment with IL-1β upregulated endothelial VCAM1 and Notch ligand Jagged1. IL-1β decreased Notch1 mRNA levels, but levels of the active Notch1ICD protein remained constant. IL-1β-mediated VCAM1 induction was downregulated in endothelial cells subjected to pretreatment with a pharmacological inhibitor of the γ-secretase, which activates Notch receptors, producing NotchICD. It was also downregulated in cells in which Notch1 and/or Jagged1 were silenced.Conversely, the forced expression of Notch1ICD in naïve endothelial cells upregulated VCAM1 per se and amplified IL-1β-mediated VCAM1 induction. Jagged1 levels increased and Notch4 signaling was downregulated in parallel. Finally, Notch1ICD and Jagged1 expression was upregulated in the endothelium of the liver in a model of chronic liver inflammation.In conclusion, we describe here a cell-autonomous, pro-inflammatory endothelial Notch1-Jagged1 circuit (i) triggering the expression of VCAM1 even in the absence of inflammatory cytokines and (ii) enhancing the effects of IL-1β. Thus, IL-1β regulates Notch1 and Notch4 activity in opposite directions, consistent with a selective targeting of Notch1 in inflamed endothelium
Uma análise do raciocínio utilizado pelos alunos ao resolverem os problemas propostos nas atividades de conhecimento físico
A partir de reflexões, surgiu o interesse de verificarmos se nas aulas de ciências nas quais foram aplicadas as atividades de conhecimento físico, os alunos do ensino fundamental, encontram condições para desenvolverem, através da metodologia de ensino por investigação, argumentos que concordem com o padrão “se, e, então, e/mas, portanto”, proposto por Lawson (2002, 2004), muito presente em importantes descobertas científicas. Para realizarmos nossa análise com maior precisão, também fizemos uso do “layout dos argumentos”, sugerido por Toulmin (2001). Isso possibilitou que verificássemos, nas aulas, durante as etapas metodológicas caracterizadas como experimentais, das perguntas do “como?” e do “por quê?” , indícios de como as explicações dos alunos evoluíram, passando da coleta dos dados e da formulação e teste de hipóteses à verificação das relações entre as variáveis e, segundo Piaget (1976), ao estabelecimento de sistemas de compensações
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