Fabrication of nanofiber coated with l-arginine via electrospinning technique: a novel nanomatrix to counter oxidative stress under crosstalk of co-cultured fibroblasts and satellite cells

The objective of this study was to synthesize and characterize novel polyurethane (PU)-nanofiber coated with l-arginine by electrospinning technique. This study determined whether l-arginine conjugated with PU-nanofiber could stimulate cell proliferation and prevent H₂O₂-induced cell death in satellite cells co-cultured with fibroblasts isolated from Hanwoo (Korean native cattle). Our results showed that l-arginine conjugated with PU nanofiber could reduce cytotoxicity of co-cultured satellite cells. Protein expression levels of bcl-2 were significantly upregulated whereas those of caspase-3 and caspase-7 were significantly downregulated in co-culture of satellite cells compared to those of monoculture cells after treatment with PU-nanofiber coated with l-arginine and which confirmed by Confocal microscope. These results suggest that co-culture of satellite cells with fibroblasts might be able to counter oxidative stress through translocation/penetration of antioxidant, collagen, and molecules secreted to satellite cells. Therefore, this nanofiber might be useful as a wound dressing in animals to counter oxidative stresses.     

Lipin 2 Binds Phosphatidic Acid by the Electrostatic Hydrogen Bond Switch Mechanism Independent of Phosphorylation

Lipin 2 is a phosphatidic acid phosphatase (PAP) responsible for the penultimate step of triglyceride synthesis and dephosphorylation of phosphatidic acid (PA) to generate diacylglycerol. The lipin family of PA phosphatases is composed of lipins 1–3, which are members of the conserved haloacid dehalogenase superfamily. Although genetic alteration of LPIN2 in humans is known to cause Majeed syndrome, little is known about the biochemical regulation of its PAP activity. Here, in an attempt to gain a better general understanding of the biochemical nature of lipin 2, we have performed kinetic and phosphorylation analyses. We provide evidence that lipin 2, like lipin 1, binds PA via the electrostatic hydrogen bond switch mechanism but has a lower rate of catalysis. Like lipin 1, lipin 2 is highly phosphorylated, and we identified 15 phosphosites. However, unlike lipin 1, the phosphorylation of lipin 2 is not induced by insulin signaling nor is it sensitive to inhibition of the mammalian target of rapamycin. Importantly, phosphorylation of lipin 2 does not negatively regulate either membrane binding or PAP activity. This suggests that lipin 2 functions as a constitutively active PA phosphatase in stark contrast to the high degree of phosphorylation-mediated regulation of lipin 1. This knowledge of lipin 2 regulation is important for a deeper understanding of how the lipin family functions with respect to lipid synthesis and, more generally, as an example of how the membrane environment around PA can influence its effector proteins.     

New derivatives of xanthenone-4-acetic acid: synthesis, pharmacological profile and effect on TNF-alpha and NO production by human immune cells

New derivatives of xanthenone-4-acetic acid, bearing an alkoxy chain of variable length and a basic moiety, were synthesised in order to test the influence of this additional function on antitumour activity. The introduction of bulky substituents carrying a basic nitrogen seems to be somewhat tolerated, since for some of the compounds the enhancement of lytic potential of human monocytes was comparable to that of the reference molecule DMXAA. The induction of the release of TNF-alpha and nitric oxide by human monocytes, as well as the hypothesis of a potentiation of the activity of lipopolysaccharide in the induction of those cytotoxic factors, was also evaluated. In this respect, the most interesting compound (6a) exhibited the same spectrum of biological activity shown by DMXAA and seems therefore to be endowed with the same mechanism of action of the reference compound.     

Cardiovascular hybrid drugs: new benzazepinone derivatives as bradycardic agents endowed with selective beta1-non-competitive antagonism

The synthesis and pharmacological profile of some hybrid compounds bearing both the benzazepinone moiety present in Zatebradine and typical beta-blocker aryloxypropanolamine groups are described. The new compounds proved to be endowed with negative chronotropic and inotropic activity and are weak vasorelaxant agents. The cardiodepressant action is probably due to selective beta(1)-noncompetitive reversible antagonism. Both enantiomers of the most active compound 5c were synthesized and they showed a different cardiovascular profile, that is (+)-(R)-enantiomer displays affinity for cardiac beta(1)-adrenoceptors, while (-)-(S)-enantiomer shows specificity for vessel smooth muscle.     

Outcomes of Acute Chest Syndrome in Adult Patients with Sickle Cell Disease: Predictors of Mortality

Adults with sickle cell disease(SCD) are a growing population. Recent national estimates of outcomes in acute chest syndrome(ACS) among adults with SCD are lacking. We describe the incidence, outcomes and predictors of mortality in ACS in adults. We hypothesize that any need for mechanical ventilation is an independent predictor of mortality.

Methods

We performed a retrospective analysis of the Nationwide Inpatient Sample(2004–2010),the largest all payer inpatient database in United States, to estimate the incidence and outcomes of ACS needing mechanical ventilation(MV) and exchange transfusion(ET) in patients >21 years. The effects of MV and ET on outcomes including length of stay(LOS) and in-hospital mortality(IHM) were examined using multivariable linear and logistic regression models respectively. The effects of age, sex, race, type of sickle cell crisis, race, co-morbid burden, insurance status, type of admission, and hospital characteristics were adjusted in the regression models.

Results

Of the 24,699 hospitalizations, 4.6% needed MV(2.7% for <96 hours, 1.9% for ≥96 hours), 6% had ET, with a mean length of stay(LOS) of 7.8 days and an in-hospital mortality rate(IHM) of 1.6%. There was a gradual yearly increase in ACS hospitalizations that needed MV(2.6% in 2004 to 5.8% in 2010). Hb-SS disease was the phenotype in 84.3% of all hospitalizations. After adjusting for a multitude of patient and hospital related factors, patients who had MV for <96 hours(OR = 67.53,p<0.01) or those who had MV for ≥96 hours(OR = 8.73,p<0.01) were associated with a significantly higher odds for IHM when compared to their counterparts. Patients who had MV for ≥96 hours and those who had ET had a significantly longer LOS in-hospitals(p<0.001).

Conclusion

In this large cohort of hospitalized adults with SCD patients with ACS, the need for mechanical ventilation predicted higher mortality rates and increased hospital resource utilization. Identification of risk factors may enable optimization of outcomes.     

Infection Related Never Events in Pediatric Patients Undergoing Spinal Fusion Procedures in United States: Prevalence and Predictors

Objective

To examine the prevalence and predictors of infection related never events (NE) associated with spinal fusion procedures (SFP) in children (age < = 18 years) in the United States.

Methods

We performed a retrospective analysis of the Nationwide Inpatient Sample for the years 2004 to 2008. All pediatric hospitalizations that underwent SFP were selected for analysis. The main outcomes measures include occurrence of certain NE’s. The association between the occurrence of a NE and factors (patient & hospital related) were examined using multivariable logistic regression analysis.

Results

Of 56,465 hospitalizations, 61.7% occurred among females. The average age was 13.7 y and two-thirds were whites. The major insurance payer was private insurance (67.4%). About 82% of all hospitalizations occurred on an elective basis. Teaching hospitals accounted for a majority of hospitalizations (87.9%). Two-thirds were posterior fusion techniques, 52.3% had underlying musculoskeletal deformities, and the most frequently present co-morbid conditions (CMC) included paralysis (10.9%), chronic pulmonary disease (9.7%), and fluid/electrolyte disorders (7.6%). Overall rate of occurrence of a NE was 4.8%. Post-operative pneumonia was the most frequently occurring NE (2.9%). Female gender (OR = 0.78) and elective admissions (OR = 0.66) were associated with lower risk of NE occurrence. Medicaid coverage (OR = 1.46), primary diagnosis of other acquired deformities (OR = 1.82), spinal cord injury (OR = 6.94), other nervous system disorders (OR = 2.84) were associated with higher risk of NE occurrence. Among CMC, those with chronic blood loss anemia (OR = 2.57), coagulopathy (OR = 1.97), depression (OR = 2), drug abuse (OR = 3.71), fluid/electrolyte disorders (OR = 2.62), neurological disorders (OR = 1.72), paralysis (OR = 1.75), renal failure (OR = 5.45), and weight loss (OR = 4.61) were risk factors for higher odds of a NE occurrence. Hospital teaching status, region, hospital size, and patient race did not influence the occurrence of NE.

Conclusion

The never events examined in the current study occurred in 4.8% of children hospitalized with SFP. Certain predictors of NE are identified in this study.     

Synthesis and biological activity of some rigid analogues of flavone-8-acetic acid

Some rigid analogues of flavone-8-acetic acid are described. Direct in vitro toxicity of the synthesised compounds was evaluated towards four tumoral cell lines and the ability of these compounds to stimulate mouse peritoneal macrophages in culture to become tumoricidal (indirect toxicity) was also studied. All compounds were able to induce direct cytotoxicity only at very high concentrations but showed a remarkable indirect activity. In particular compound 4d was able to significantly increase macrophage lytic properties and has been selected for further investigations.     

Acetylcholinesterase inhibitors for potential use in Alzheimer's disease: molecular modeling, synthesis and kinetic evaluation of 11H-indeno-[1,2-b]-quinolin-10-ylamine derivatives

Continuing our work on tetracyclic tacrine analogues, we synthesized a series of acetylcholinesterase (AChE) inhibitors of 11H-indeno-[1,2-b]-quinolin-10-ylaminic structure. Selected substituents were placed in synthetically accessible positions of the tetracyclic nucleus, in order to explore the structure-activity relationships (SAR) and the mode of action of this class of anticholinesterases. A molecular modeling investigation of the binding interaction of the lead compound (1a) with the AChE active site was performed, from which it resulted that, despite the rather wide and rigid structure of 1a, there may still be the possibility to introduce some small substituent in some positions of the tetracycle. However, from the examination of the experimental IC50 values, it derived that the indenoquinoline nucleus probably represents the maximum allowable molecular size for rigid compounds binding to AChE. In fact, only a fluorine atom in position 2 maintains the AChE inhibitory potency of the parent compound, and, actually, increases the AChE-selectivity with respect to the butyrylcholinesterase inhibition. By studying the kinetics of AChE inhibition for two representative compounds of the series, it resulted that the lead compound (1a) shows an inhibition of mixed type, binding to both the active and the peripheral sites, while the more sterically hindered analogue 2n seems to interact only at the external binding site of the enzyme. This finding seems particularly important in the context of Alzheimer's disease research in the light of recent observations showing that peripheral AChE inhibitors might decrease the aggregating effects of the enzyme on the beta-amyloid peptide (betaA).     

Multi-target-directed coumarin derivatives: hAChE and BACE1 inhibitors as potential anti-Alzheimer compounds

The complex etiology of Alzheimer's disease (AD) prompts scientists to develop multifunctional compounds to combat causes and symptoms of such neurodegeneration. To this aim we designed, synthesized, and tested a series of compounds by introducing halophenylalkylamidic functions on the scaffold of AP2238, which is a dual binding site acetylcholinesterase inhibitor. The inhibitory activity was successfully extended to the beta-site amyloid precursor protein cleavage enzyme, leading to the discovery of a potent inhibitor of this enzyme (3) and affording multifunctional compounds (2, 6, 8) for the treatment of AD.     

Multidrug resistance reverting activity and antitumor profile of new phenothiazine derivatives

A series of easily affordable phenothiazine derivatives bearing a rigid but-2-ynyl amino side chain were synthesized and tested to evaluate the MDR reverting activity and full antitumor profile. Some compounds endowed with remarkable MDR reverting effect were identified, and the most active one (6c) was shown to increase doxorubicin retention in multidrug resistant cells, suggesting a direct interaction with P-glycoprotein. Furthermore, a broad range of cellular activities were observed for different compounds. In particular, the ability of some derivatives to induce antiproliferative effects on resistant cell lines and to interfere with the G(1) phase of the cell cycle, a phase usually not affected by classical antitumor agents, was noted. Moreover, the most cytotoxic compounds of the series were able to induce apoptosis in resistant cell lines, via an atypical pathway of caspase cascade activation, and a synergistic effect in combination with doxorubicin was also found.