Comparative study of alpha‐ and beta‐pinene effect on PTZ‐induced convulsions in mice

Convulsions occur in response to a loss of balance between excitatory and inhibitory neurotransmitters, and the treatment for this condition consists in restore such lost balance. Many anticonvulsant drugs present side effects which may limit their use. This fact has stimulated the search for new sources of treatment from aromatic plants. Many monoterpenes commonly present in essential oils are known because of their anticonvulsant properties. The anticonvulsant effect of α‐ and β‐pinene, two structural isomers, is still little studied. Thus, the present work evaluated the anticonvulsant effect of α‐ and β‐pinene in pentylenetetrazole‐induced convulsions model. Initially, the oral LD₅₀ for α‐ and β‐pinene was estimated. Following the oral administration, a mild sedation was observed and no deaths were recorded; the LD₅₀ estimated for both monoterpenes was greater than 2 000 mg/kg, p.o. Further, animals were orally treated with α‐pinene (100, 200 and 400 mg/kg), β‐pinene (100, 200 and 400 mg/kg) and the equimolar mixture of α‐ and β‐pinene (400 mg/kg) and subjected to the pentylenetetrazole‐induced convulsions model. In this model, only the dose of 400 mg/kg of the compounds was able to significantly decrease the seizure intensity. The latency of first convulsion was significantly increased by the mixture of α‐ and β‐pinene (400 mg/kg). In addition, β‐pinene and the mixture of the two monoterpenes, both at a dose of 400 mg/kg, significantly increased the time of death of animals. The treatment with β‐pinene and the equimolar mixture of the two monoterpenes significantly reduced hippocampal nitrite level and striatal content of dopamine (DA) and norepinephrine (NE). Taken together, the results suggest that α‐pinene appears to be devoid of anticonvulsant action. This fact, however, seems to be dependent on the chemical structure of the compound, since pretreatment with the β‐pinene increased the time of death pf PTZ‐treated mice, which seems to depend on the ability of the compound to reduce nitrite concentration and NE and DA content, during the pentylenetetrazole‐induced seizure.     

Anti‐inflammatory effect of 4‐methylcyclopentadecanone in rats submitted to ischemic stroke

This study aimed to investigate the anti‐inflammatory effect of 4‐methylcyclopentadecanone (4‐MCPC) in rats suffering from a cerebral ischemia/reperfusion (I/R) injury. In this study, the focal cerebral ischemia in rats was induced by middle cerebral artery occlusion (MCAO) for 2 h, and the rats were treated with 4‐MCPC (8 mg/kg) just 0.5 h before reperfusion. The ischemic infarct volume was recorded 24 h after the MCAO. In addition, myeloperoxidase (MPO) activity and TNF‐α and IL‐1β levels in the ischemic cerebral cortex were determined by ELISA, while nuclear translocation of NF‐κB p65 subunit and expression of p‐IκBα were investigated by Western blotting. Our results showed that 4‐MCPC treatment decreased infarct volume significantly, compared with I/R group (16.8%±7.5% vs. 39.7%±10.9%); it reduced MPO activity (0.43 ± 0.10 vs. 1.00 ± 0.51 U/g) and expression levels of TNF‐α (18.90 ± 3.65 vs. 35.87 ± 4.87 ng/g) and IL‐1β (1.68 ± 0.23 vs. 2.67 ± 0.38 ng/g) in ischemic brain tissues of rats. Further study revealed that 4‐MCPC treatment markedly reduced nuclear translocation of NF‐κB p65 subunit and expression of p‐IκBα in ischemic cerebral cortex. Taken together, our results suggest that 4‐MCPC protects against cerebral I/R injury and displays anti‐inflammatory actions through inhibition of the NF‐κB signal pathway.     

Functional association of phosphoinositide‐3‐kinase with platelet glycoprotein Ibα, the major ligand‐binding subunit of the glycoprotein Ib–IX–V complex

Summary. Background: The adhesion receptor glycoprotein (GP)Ib–IX–V, which binds von Willebrand factor (VWF) and other ligands, initiates platelet activation and thrombus formation at arterial shear rates, and may control other vascular processes, such as coagulation, inflammation, and platelet‐mediated tumor metastasis. The cytoplasmic C‐terminal domain of the ligand‐binding GPIbα subunit contains binding sites for filamin (residues 561–572, critically Phe568/Trp570), 14‐3‐3ζ (involving phosphorylation sites Ser587/590 and Ser609), and the phosphoinositide‐3‐kinase (PI3‐kinase) regulatory subunit, p85. Objectives: We previously showed that, as compared with wild‐type receptor, deleting the contiguous sequence 580–590 or 591–610, but not upstream sequences, of GPIbα expressed as a GPIb–IX complex in Chinese hamster ovary cells inhibited VWF‐dependent Akt phosphorylation, which is used as a read‐out for PI3‐kinase activity. Pulldown experiments using glutathione‐S‐transferase (GST)–p85 or GST–14‐3‐3ζ constructs, and competitive inhibitors of 14‐3‐3ζ binding, suggested an independent association of 14‐3‐3ζ and PI3‐kinase with GPIbα. The objective of this study was to analyze a further panel of GPIbα deletion mutations within residues 580–610. Results: We identified a novel deletion mutant, Δ591–595, that uniquely disrupts 14‐3‐3ζ binding but retains the functional p85/PI3‐kinase association. Deletion of other sequences within the 580–610 region were less discriminatory, and either partially affected p85/PI3‐kinase and 14‐3‐3ζ binding (Δ580–585, Δ586–590, Δ596–600, Δ601–605), or strongly inhibited binding of both proteins (Δ606–610). Conclusions: Together, these findings have significant implications for interpreting the functional role of p85 and/or 14‐3‐3ζ in GPIb‐dependent signaling or platelet functional studies involving truncation of the C‐terminal residues in cell‐based assays and mouse models. The Δ591–595 mutation provides another strategy for determining the function of GPIbα‐associated 14‐3‐3ζ by selective disruption of 14‐3‐3ζ but not p85/PI3‐kinase binding.     

Antibacterial and β‐Lactamase Inhibitory Activity of Monocyclic β‐Lactams

Due to the widespread emergence of resistant bacterial strains, an urgent need for the development of new antibacterial agents with novel modes of action has emerged. The discovery of naturally occurring monocyclic β‐lactams in the late 1970s, mainly active against aerobic Gram‐negative bacteria, has introduced a new approach in the design and development of novel antibacterial β‐lactam agents. The main goal was the derivatization of the azetidin‐2‐one core in order to improve their antibacterial potency, broaden their spectrum of activity, and enhance their β‐lactamase stability. In that respect, our review covers the updates in the field of monocyclic β‐lactam antibiotics during the last three decades, taking into account an extensive collection of references. An overview of the relationships between the structural features of these monocyclic β‐lactams, classified according to their N‐substituent, and the associated antibacterial or β‐lactamase inhibitory activities is provided. The different paragraphs disclose a number of well‐established classes of compounds, such as monobactams, monosulfactams, monocarbams, monophosphams, nocardicins, as well as other known representative classes. Moreover, this review draws attention to some less common but, nevertheless, possibly important types of monocyclic β‐lactams and concludes by highlighting the recent developments on siderophore‐conjugated classes of monocyclic β‐lactams.     

Mobilization effects of G‐CSF,GM‐CSF,and darbepoetin‐α for allogeneic peripheral blood stem cell transplantation

The effects of GM‐/G‐CSF and darbepoetin‐α on stem cell mobilization were investigated. From February 2005 to March 2007, 30 allogeneic sibling donors were randomly assigned to a G‐CSF group (5 μg/kg/day for 5–7 days) or triple group (GM‐CSF 10 μg/kg/day on 1st and 2nd day, G‐CSF 5 μg/kg/day for 5–7 days, and darbepoetin‐α 40 mg on 1st day). The MNCs and CD34⁺ cells were not different between the two groups, although the doses (×10⁸/kg of recipient body weight) of CD3⁺ cells (3.64 ± 1.75 vs. 2.63 ± 1.36, P = 0.089) and CD8⁺ cells (1.07 ± 0.53 vs. 0.60 ± 0.30, P = 0.006) were lower in the triple group. The engraftments, frequency of RBC transfusions, and hemoglobin recovery were not different between the two groups. The cumulative incidence of overall and Grades II–IV aGVHD was 64.3% vs. 61.1% and 25.9% vs. 27.1% in the G‐CSF and triple regimen group, respectively, whereas the cumulative incidence of cGVHD was 20.8 ± 1.3% and 24.4 ± 1.7%, respectively. In conclusion, the triple regimen did not seem to be superior to G‐CSF alone in terms of the CD34+ cell dose, hemoglobin recovery, and GVHD. However, the CD8+ cell count was significantly lower in the triple regimen group. The role of a lower CD8+ cell count in the graft may need to be elucidated in the future. J. Clin. Apheresis, 2009. © 2009 Wiley‐Liss, Inc.     

Synthesis and characterization of poly(glycerol‐co‐sebacate‐co‐ε‐caprolactone) elastomers

In this study, poly(glycerol‐co‐sebacate‐co‐ε‐caprolactone) (PGSCL) elastomers were synthesized for the first time from the respective monomers. The structural analysis of PGSCL elastomers by nuclear magnetic resonance (¹H‐NMR) and Fourier transform infrared spectroscopy (FTIR) revealed that the elastomers have a high number of hydrogen bonds and crosslinks. X‐ray diffraction (XRD) and thermal analysis indicated an amorphous state. Differential scanning calorimetry (DSC) analysis showed that the elastomers has a glass transition temperature (T_g) of –36.96°C. The Young's modulus and compression strength values were calculated as 46.08 MPa and 3.192 MPa, respectively. Calculations based on acid number and end groups analysis revealed a number average molecular weight of 148.15 kDa. Even though the foaming studies conducted by using supercritical CO₂ resulted in a porous structure; the obtained morphology tended to disappear after 48 h, leaving small cracks on the surface. This phenomenon was interpreted as an indication of self‐healing due to the high number of hydrogen bonds. The PGSCL elastomers synthesized in this study are flexible, robust to compression forces and have self‐healing capacity. Thanks to good biocompatibility and poor cell‐adhesion properties, the elastomers may find diverse applications where a postoperative adhesion barrier is required. Copyright © 2013 John Wiley & Sons, Ltd.     

Comparison of behavioral,neuroprotective, and proinflammatory cytokine modulating effects exercised by (+)‐cis‐EC and (−)‐cis‐EC stereoisomers in a PTZ‐induced kindling test in mice

Epoxy‐carvone (EC) has chiral centers that allow generation of stereoisomers, including (+)‐cis‐EC and (?)‐cis‐EC, whose effects in the kindling tests have never been studied. Accordingly, this study aims to comparatively investigate the effect of stereoisomers (+)‐cis‐epoxy‐carvone and (?)‐cis‐epoxy‐carvone on behavioral changes measured in scores, in the levels of cytokines (IL‐1β, IL‐6, and TNFα) and neuronal protection in the face of continuous treatment with pentylenetetrazol. Swiss mice were divided into five groups (n = 10), receiving vehicle, (+) – cis‐EC, (?) – cis‐EC (both at the dose of 30 mg/kg), and diazepam (4 mg/kg). Thirty minutes after the respective treatment was administered to the animals one subconvulsive dose of PTZ (35 mg/kg). Seven subconvulsives treatments were made on alternate days, in which each treatment several parameters were recorded. In the eighth treatment, the animals receiving the highest dose of PTZ (75 mg/kg) and were sacrificed for quantification of cytokines and histopathologic analysis. All drugs were administered by intraperitoneal route. In the kindling test, (+)‐cis‐EC and (?)‐cis‐EC reduced the average scores. The stereoisomer (+)‐cis‐EC decreased levels of proinflammatory cytokines IL‐1β, IL‐6, and TNFα, whereas comparatively (?)‐cis‐EC did not reduce IL‐1β levels. Histopathological analysis of the mice hippocampi undergoing this methodology showed neural protection for treated with (+)‐cis‐EC. The results suggest that the anticonvulsant effect of (+)‐cis‐EC possibly takes place due to reduction of proinflammatory cytokines involved in the epileptogenic process, besides neuronal protection, yet further investigation of the mechanisms involved is required.     

Fast clearing RGD‐based near‐infrared fluorescent probes for in vivo tumor diagnosis

A fast clearing hydrophilic near‐infrared (NIR) dye ICG‐Der‐02 was used to constitute tumor targeting contrast agents. Cell adhesion molecule integrin α_vβ₃ served as the target receptor because of its unique expression on almost all sprouting tumor vasculatures. The purpose of this study was to synthesize and compare the properties of integrin α_vβ₃‐targeted, fast clearing NIR probes both in vitro and in vivo for tumor diagnosis. ICG‐Der‐02 was covalently conjugated to three kinds of RGD peptide including linear, monoeric cyclic and dimeric RGD to form three RGD‐based NIR probes. The integrin receptor specificities of these probes were evaluated in vitro by confocal microscopy. The dynamic bio‐distribution and elimination ratse were in vivo real‐time monitored by a near‐infrared imaging system in normal mice. Further, the in vivo tumor targeting abilities of the RGD‐based NIR probes were compared in α_vβ₃‐positive MDA‐MB‐231, U87MG and α_vβ₃‐negtive MCF‐7 xenograft mice models. Three RGD‐based NIR probes were successfully synthesized with good optical properties. In vitro cellular experiments indicated that the probes have a clear binding affinity to α_υβ₃‐positive tumor cells, with a cyclic dimeric RGD probe owing the highest integrin affinity. Dynamic bio‐distributions of these probes showed a rapid clearing rate through the renal pathway. In vivo tumor targeting ability of the RGD‐based porbes was demonstrated on MDA‐MB‐231 and U87MG tumor models. As expected, the c(RGDyK)₂‐ICG‐Der‐02 probe displayed the highest tumor‐to‐normal tissue contrast. The in vitro and in vivo block experiments confirmed the receptor binding specificity of the probes. The hydrophilic dye‐labeled NIR probes exhibited a fast clearing rate and deep tissue penetration capability. Further, the α_υβ₃ receptor affinity of the three RGD‐based NIR probes followed the order of dimer cyclic > monomer cyclic > linear. The results demonstrate potent fast clearing probes for in vivo early tumor diagnosis. Copyright © 2012 John Wiley & Sons, Ltd.     

New definitions of extended‐spectrum β‐lactamase conferring worldwide emerging antibiotic resistance

Although there is no consensus of the precise definition of ESBL, three kinds of ESBL definitions have been proposed. First, the classical definition includes variants derived from TEM‐1, TEM‐2, or SHV‐1; K1 (KOXY) of Klebsiella oxytoca. Second, the broadened definition has stretched the classical definition of ESBL to include: (1) β‐lactamases (CTX‐M‐ESBLs, GES‐ESBLs, and VEB‐ESBLs), with spectra similar to those of TEM and SHV variants (designated as TEM‐ and SHV‐ESBLs, respectively) but derived from other sources; (2) TEM and SHV variants with borderline ESBL activity; e.g., TEM‐12; and (3) various β‐lactamases conferring wider resistance than their parent types but not meeting the definition for group 2be; e.g., OXA‐types (OXA‐ESBLs) and mutant AmpC‐types (AmpC‐ESBLs), with increased activity against oxyimino‐cephalosporins and with resistance to clavulanic acid. Third, the all‐inclusive definition includes: (1) ESBL_A (named for class A ESBLs); (2) ESBL_M (miscellaneous ESBLs), which has been subdivided into ESBL_M‐C (class C; plasmid‐mediated AmpC) and ESBL_M‐D (class D); and (3) ESBL_CARBA (ESBLs with hydrolytic activity against carbapenems), which has been subdivided into ESBL_CARBA‐A (class A carbapenemases), ESBL_CARBA‐B (class B carbapenemases), and ESBL_CARBA‐D (class D carbapenemases). The consensus view about the ESBL definition is that the classical ESBL definition must be expanded to class A non‐TEM‐ and non‐SHV‐ESBLs (CTX‐M‐, GES‐, VEB‐ESBLs, etc.). However, these three definitions evoke rational debate on the question “Which would be included in the category of ESBLs among AmpC‐ESBLs, OXA‐ESBLs, and/or carbapenemases?” Therefore, there is a great need for consensus in the precise definition of ESBL. © 2010 Wiley Periodicals, Inc. Med Res Rev 32:216‐232, 2012     

Implementation of evidence‐based practice by nurses working in community settings and their strategies to mentor student nurses to develop evidence‐based practice: A qualitative study

The aim of the study was to explore how community nurses apply the best available evidence to their practice, and how they mentor student nurses to conceptualize and implement evidence‐based practice in community settings. In the UK, the expansion of health‐care provision in the community has supported the development of highly skilled community nurses. However, there is limited literature regarding the strategies used by community nurses to implement evidence‐based practice and mentor student nurses to conceptualize evidence‐based practice in community placements. An exploratory qualitative approach applying inductive reasoning to focus group data was used. As a result, nurses working for a community NHS Foundation Trust in South England with a mentor qualification were invited to participate in one of the seven focus groups, 33 nurses participated. Data were analyzed with thematic analysis. The themes discussed in this paper are: ‘our practice is evidence‐based’ as guidelines and policies provided structure, but occasionally stifled autonomous clinical decision‐making, and ‘time’ as a barrier and facilitator to mentoring student nurses in community settings. In conclusion, nurses need to develop the ability to incorporate patients' needs and wishes within evidence‐based care. Time was a facilitator for some community mentors, but protected time is required to complete the necessary practice documentation of student nurses.     

Effects of variation in the human α2A‐ and α2C‐adrenoceptor genes on cognitive tasks and pain perception

Background: The mechanisms underlying interindividual variability in pain perception and cognitive responses are undefined but highly heritable. α_2C‐ and α_2A‐adrenergic receptors regulate noradrenergic activity and are important mediators of pain perception and analgesia. We hypothesized that common genetic variants in these genes, particularly the ADRA2C 322–325 deletion variant, affect pain perception or cognitive responses. Methods: We studied 73 healthy subjects (37 Caucasians and 36 African–Americans) aged 25.4 ± 4.6 years. Pain response to a cold pressor test was measured using a 10 cm visual analog scale and again on the next day, after three infusions of the selective α₂‐agonist dexmedetomidine. Standardized cognitive tests were administered at baseline and after each infusion. The contribution of ADRA2C deletion genotype, dexmedetomidine concentration, and other covariates to pain perception and cognitive responses was determined using multiple linear regression models. Secondary analysis examined the effects of ADRA2A and other ADRA2C variants on pain perception. Results: ADRA2C Del homozygotes had higher pain scores in response to cold at baseline (6.3 ± 1.8 cm) and after dexmedetomidine (5.6 ± 2.2 cm) than insertion allele carriers (4.6 ± 2.1 cm [baseline] and 3.8 ± 1.9 cm [after dexmedetomidine]; adjusted P‐values = 0.019 and 0.004, respectively). Cognitive responses were unrelated to ADRA2C Ins/Del genotype. None of the other ADRA2A and ADRA2C variants was significantly related to cold pain sensitivity before dexmedetomidine; after dexmedetomidine, ADRA2A rs1800038 was marginally associated (P = 0.03). Conclusion: The common ADRA2C del322–325 variant affected pain perception before and after dexmedetomidine but did not affect other cognitive responses, suggesting that it contributes to interindividual variability in pain perception.