Two aromatic diamidines, furamidine (DB75) and its phenyl-substituted analogue (DB569), which exhibit trypanocidal activity, were assayed against Trypanosoma cruzi and were found to induce ...apoptosis-like death characteristics such as nuclear DNA condensation and fragmentation, decreased mitochondrial membrane potential and phosphatidylserine exposure. DB569 displays superior trypanocidal activity compared to furamidine and also had higher ability to induce apoptosis-like death in treated parasites. The present results showing apoptosis-like death in T. cruzi after treatment with both DB75 and DB569 make important contributions to the understanding of the mechanisms of the aromatic diamidines, which represent promising trypanocidal compounds.
•New SPIF geometry with strain pairs in the shear fracture forming limit line (SFFL).•Reopen the discussion on plastic flow and failure in SPIF.
The aim of this paper is twofold: firstly, to identify ...a new failure mechanism by in-plane shear cracking in single point incremental forming (SPIF) and, secondly, to present a simple geometry to be produced by SPIF that is capable of providing fracture strain pairs to define the in-plane shear fracture forming line (SFFL) corresponding to crack opening by mode II of fracture mechanics. The methodology draws from the analysis of several pioneering studies in SPIF, where strain loading paths evolve in the tension–compression quadrant of the principal strain space, to setting up an experimental work plan aimed at identifying the forming conditions where crack opening by thinning under tension is replaced with crack opening by in-plane shear (distortion with limited thinning). The overall procedure makes use of circle-grid analysis and thickness measurements before and after fracture at several locations along the cracks in order to obtain the ‘gauge length’ strains. It is shown that a truncated four-lobe conical shape with varying drawing angle can be successfully employed to define the SFFL and to reopen the discussion around the physics behind plastic flow and fracture in SPIF.
The role of calcification in coronary artery disease is gaining importance, both in research studies and in clinical application. Calcified plaque has long been considered to be the most important ...atherosclerotic plaque within the arterial tree and frequently presents a challenge for percutaneous intervention. Current investigations have shown that plaque calcification has a dynamic course that is closely related to the magnitude of vascular inflammation. Numerous inflammatory factors synthesized during the early stages of atherosclerosis induce the expression and activation of osteoblast-like cells localized in the arterial wall that produce calcium. There is no doubt that the role of these factors in calcification associated with coronary artery disease could be a crucial strategic point in prevention and treatment. A number of diagnostic imaging methods have been developed in recent years, but their performance needs to be improved. In this context, we undertook an update on coronary calcification, focusing on physiopathology, clinical implications, and imaging techniques.
Dual antiplatelet therapy is recommended for patients with acute coronary syndromes (ACS). Approximately 10% to 15% of these patients will undergo coronary artery bypass graft (CABG) surgery for ...index events, and current guidelines recommend stopping clopidogrel at least 5 days before CABG. This waiting time has clinical and economic implications.
This study aimed to evaluate if a platelet reactivity-based strategy is noninferior to standard of care for 24-h post-CABG bleeding.
In this randomized, open label noninferiority trial, 190 patients admitted with ACS with indications for CABG and on aspirin and P2Y12 receptor inhibitors, were assigned to either control group, P2Y12 receptor inhibitor withdrawn 5 to 7 days before CABG, or intervention group, daily measurements of platelet reactivity by Multiplate analyzer (Roche Diagnostics GmbH, Vienna, Austria) with CABG planned the next working day after platelet reactivity normalization (pre-defined as ≥46 aggregation units).
Within the first 24 h of CABG, the median chest tube drainage was 350 ml (interquartile range IQR: 250 to 475 ml) and 350 ml (IQR: 255 to 500 ml) in the intervention and control groups, respectively (p for noninferiority <0.001). The median waiting period between the decision to undergo CABG and the procedure was 112 h (IQR: 66 to 142 h) and 136 h (IQR: 112 to 161 h) (p < 0.001), respectively. In the intention-to-treat analysis, a 6.4% decrease in the median in-hospital expenses was observed in the intervention group (p = 0.014), with 11.2% decrease in the analysis per protocol (p = 0.003).
A strategy based on platelet reactivity-guided is noninferior to the standard of care in patients with ACS awaiting CABG regarding peri-operative bleeding, significantly shortens the waiting time to CABG, and decreases hospital expenses. (Evaluation of Platelet Aggregability in the Release of CABG in Patients With ACS With DAPT; NCT02516267)
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Human alpha2-macroglobulin (α2M) is a 720kDa glycoprotein that presents two ultrastructural conformations: slow (S-α2M) and fast (F-α2M). α2M acts mainly as a proteinase scavenger, but an ...immunomodulatory role was also proposed. This work studies the effect of desialylation and deglycosylation on the structure patterns of α2M by ultrastructural analysis of lectin-induced aggregates, which represents a new approach that had never been previously used. Transmission electron microscopy (TEM) analysis showed the loss of S-α2M conformation after deglycosylation, indicating that glycosidic side-chains contribute to the molecular stability of S-α2M. TEM proved to be an important tool to analyze the effect of biochemical changes on α2M, yielding an objective qualitative control of its morphological state. Certain carbohydrate residues did not vary between the α2M conformations, since both bound similarly ConA and WGA lectins. However, the binding of PNA and BSI-B4 was slightly lower in F-α2M than in S-α2M. Among the neuraminidases used to desialylate both conformations of α2M that from Arthrobacter ureafaciens was the most effective. Incubation with the lectins ConA or SNA, respectively specific for mannosyl and sialyl residues, led to dose-dependent patterns of aggregation of α2M molecules, mediated by lectin binding and clearly visualized by TEM.
The polyphenol compound Kaempferol, a relevant member of the class of flavonoids, is a good example where coordination to Zn(II) ion was found to improve the anticancer effects compared to the free ...ligand. Determination of the metal‐complex molecular structure (and binding sites on Kaempferol) in the liquid phase is fundamental for an understanding of biological activities. Experimental UV‐Vis and EPR data only provide indirect evidence or limited structural information. Therefore, theoretical study of structural and spectroscopic properties of the metal‐polyphenol complex, using computational quantum chemistry methods, is certainly relevant as starting point for the investigation of mechanism of action at a molecular level. In this article, we used the density functional theory (DFT) methodology to predict the molecular structure of Zn(Kaempferol)(H2O)n+ and Zn(Kaempferol)2(H2O)n complexes (n = 0, 2, or 4) and B‐ring nonplanar conformation of flavonoid using as strategy the best match between theoretical and experimental 1H NMR, IR, and UV‐Vis spectroscopic data in solution. These are valuable information for further studies involving structure‐activity relationship.
Kaempferol, a flavonoid extracted from the Camellia sinensis, has several biological activities. According to the literature, Zn(II)‐kaempferol complexes exhibit higher antitumor activity than free flavonoid. Therefore, the elucidation of the complex structure in solution constitutes one of the main properties to study its mechanism of interaction with DNA. This article shows unpublished results obtained through a DFT study of the structures and their 1H NMR spectra in solution of different geometries for this complex.
Calcium channels control the inflow of calcium ions into cells and are involved in diverse cellular functions. The CACNA1C gene polymorphism rs1006737 A allele has been strongly associated with ...increased risk for bipolar disorder (BD) and with modulation of brain morphology. The medial prefrontal cortex (mPFC) has been widely associated with mood regulation in BD, but the role of this CACNA1C polymorphism in mPFC morphology and brain aging has yet to be elucidated. One hundred seventeen euthymic BD type I subjects were genotyped for CACNA1C rs1006737 and underwent 3 T three-dimensional structural magnetic resonance imaging scans to determine cortical thickness of mPFC components (superior frontal cortex (sFC), medial orbitofrontal cortex (mOFC), caudal anterior cingulate cortex (cACC) and rostral anterior cingulate cortex (rACC)). Carriers of the CACNA1C allele A exhibited greater left mOFC thickness compared to non-carriers. Moreover, CACNA1C A carriers showed age-related cortical thinning of the left cACC, whereas among A non-carriers there was not an effect of age on left cACC cortical thinning. In the sFC, mOFC and rACC (left or right), a negative correlation was observed between age and cortical thickness, regardless of CACNA1C rs1006737 A status. Further studies investigating the direct link between cortical thickness, calcium channel function, apoptosis mechanism and their underlying relationship with aging-associated cognitive decline in BD are warranted.
The diagnosis and treatment of bipolar depression (BDep) poses complex clinical challenges for psychiatry. Proton magnetic resonance spectroscopy (1H-MRS) is a useful imaging tool for investigating ...in vivo levels of brain neuro-metabolites, critical to understanding the process of mood dysregulation in Bipolar Disorder. Few studies have evaluated longitudinal clinical outcomes in BDep associated with 1H-MRS metabolic changes. This study aimed to longitudinally assess brain 1H-MRS metabolites in the anterior cingulate cortex (ACC) correlated with improvement in depression (from BDep to euthymia) after lithium treatment in BDep patients versus matched healthy controls (HC). Twenty-eight medication-free BDep patients and 28 HC, matched for age and gender, were included in this study. All subjects were submitted to a 3-Tesla brain 1H-MRS scan in the ACC using a single-voxel (8cm3) PRESS sequence at baseline. At follow-up (6 weeks), 14 BDep patients repeated the exam in euthymia. Patients with current BDep had higher baseline Myo-inositol/Cr (mI/Cr) and Choline/Cr (Cho/Cr) compared to HC. After six weeks, mI/Cr or Cho/Cr levels in subjects that achieved euthymia no longer differed to levels in HC, while high Cho/Cr levels persisted in non-responders . Elevated ACC mI/Cr and Cho/Cr in BDep might indicate increased abnormal membrane phospholipid metabolism and phosphatidylinositol (PI) cycle activity. Return of mI/Cr and Cho/Cr to normal levels after lithium-induced euthymia suggests a critical regulatory effect of lithium targeting the PI cycle involved in mood regulation.
Malaria is nowadays a worldwide and serious problem with a significant social, economic, and human cost, mainly in developing countries. In addition, the emergence and spread of resistance to ...existing antimalarial therapies deteriorate the global malaria situation, and lead thus to an urgent need toward the design and discovery of new antimalarial drugs. In this work, a QSAR predictive model based on GETAWAY descriptors was developed which is able to explain with, only three variables, more than 77% of the variance in antimalarial potency and displays a good internal predictive ability (of 73.3% and 72.9% from leave-one-out cross-validation and bootstrapping analyses, respectively). The performance of the proposed model was judged against other five methodologies providing evidence of the superiority of GETAWAY descriptors in predicting the antimalarial potency of the bisbenzamidine family. Moreover, a desirability analysis based on the final QSAR model showed that to be a useful way of selecting the predictive variable level necessary to obtain potent bisbenzamidines. From the proposed model it is also possible to infer that elevated high atomic masses/polarizabilities/van der Waals volumes could play a negative/positive/positive role in the molecular interactions responsible for the desired drug conformation, which is required for the optimal binding to the macromolecular target. The results obtained point out that our final QSAR model is statistically significant and robust as well as possessing a high predictive effectiveness. Thus, the model provides a feasible and practical tool for looking for new and potent antimalarial bisbenzamidines.
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