Human NK Cells induce neutrophil apoptosis via an NKp46- and Fas-dependent mechanism

Polymorphonuclear neutrophils (PMN) are potent inflammatory effector cells essential to host defense, but at the same time they may cause significant tissue damage. Thus, timely induction of neutrophil apoptosis is crucial to avoid tissue damage and induce resolution of inflammation. NK cells have been reported to influence innate and adaptive immune responses by multiple mechanisms including cytotoxicity against other immune cells. In this study, we analyzed the effect of the interaction between NK cells and neutrophils. Coculture experiments revealed that human NK cells could trigger caspase-dependent neutrophil apoptosis in vitro. This event was dependent on cell-cell contact, and experiments using blocking Abs indicated that the effect was mediated by the activating NK cell receptor NKp46 and the Fas pathway. CD56-depleted lymphocytes had minimal effects on neutrophil survival, suggesting that the ability to induce neutrophil apoptosis is specific to NK cells. Our findings provide evidence that NK cells may accelerate neutrophil apoptosis, and that this interaction may be involved in the resolution of acute inflammation.     

Recreationist behaviour in forests and the disturbance of wildlife

Forests are popular locations for outdoor recreation and there is considerable evidence highlighting the positive social impacts of these activities. There is also a body of research outlining the range of potentially negative impacts of recreation on wildlife and habitats. This paper provides a summary of current social and natural scientific knowledge on disturbance caused by walking, cycling, mountain biking, horse riding, off-road vehicles use, camping, and some other recreational activities in forests. We identify more than 40 ecological studies of recreational impacts on forests. Greatest attention has been directed towards walking as an activity and the impacts upon birds, soils and flora although long-term ecological studies of wildlife or habitat disturbance are scarce. Impacts include trampling by foot, hoof and tyre, animal behaviour change and the spread of pests and pathogens. Considerably less work has been carried out on the social dimensions of recreational disturbance. In this article the authors draw on behaviour theory in an attempt to identify the key factors influencing human behaviour in the context of recreational disturbance. Cognitive theories highlight the importance of attitudes and behavioural control, whilst social practice theories emphasise the impact of behavioural routines and contexts. Management actions may be better targeted at promoting alternative behaviours rather than trying to prevent current ‘problem’ behaviours. We advocate greater engagement with these theories to better integrate social science with ecological studies, and improve understanding and management of interactions between recreation needs and conservation.     

Will Mobile Diabetes Education Teams (MDETs) in primary care improve patient care processes and health outcomes? Study protocol for a randomized controlled trial

ABSTRACT: BACKGROUND: There is evidence to suggest that delivery of diabetes self-management support by diabetes educators in primary care may improve patient care processes and patient clinical outcomes; however, the evaluation of such a model in primary care is nonexistent in Canada. This article describes the design for the evaluation of the implementation of Mobile Diabetes Education Teams (MDETs) in primary care settings in Canada. METHODS: This study will have a non-blinded, cluster-randomized controlled trial stepped wedge design. A cluster, randomized controlled trial will be used to evaluate the Mobile Diabetes Education Teams' intervention in improving patient clinical and care process outcomes. A total of 1,200 patient charts at participating primary care sites will be reviewed for data extraction. Eligible patients will be those aged >=18, who have type 2 diabetes and a hemoglobin A1c (HbA1c) of >=8 %. Clusters (that is, primary care sites) will be randomized to the intervention and control group using a block randomization procedure within practice size as the blocking factor. A stepped wedge design will be used to sequentially roll out the intervention so that all clusters eventually receive the intervention. The time at which each cluster begins the intervention is randomized to one of the four roll out periods (0, 6, 12, and 18 months). Clusters that are randomized into the intervention later will act as the control for those receiving the intervention earlier. The primary outcome measure will be the difference in the proportion of patients who achieve the recommended HbA1c target of <=7 % between intervention and control groups. Qualitative work (in-depth interviews with primary care physicians, MDET educators and patients; and MDET educators' field notes and debriefing sessions) will be undertaken to assess the implementation process and effectiveness of the MDET intervention.Trial registrationClinicalTrials.gov NCT01553266.     

Chemosensory protein from the moth Mamestra brassicae. Expression and secondary structure from 1H and 15N NMR.

A group of ubiquitous small proteins (average 13 kDa) has been isolated from several sensory organs of a wide range of insect species. They are believed to be involved in chemical communication and perception (olfaction or taste) and have therefore been called chemo-sensory proteins (CSPs). Several CSPs have been identified in the antennae and proboscis of the moth Mamestra brassicae. We have expressed one of the antennal proteins (CSPMbraA6) in large quantities as a soluble recombinant protein in Escherichia coli periplasm. This 112-residue protein is a highly soluble monomer of 13 072 Da with a pI of 5.5. NMR data (1H and 15N) indicate that CSPMbraA6 is well folded and contains seven alpha helices (59 amino acids) and two short extended structures (12 amino acids) from positions 5 to 10 and from 107 to 112. Thirty-seven amino acids are involved in beta turns and coiled segments and four amino acids are not assigned in the NMR spectra (the N-terminus and the residue 52 in the loop 48-53), probably due to their mobility. This is the first report on the expression and structural characterization of a recombinant CSP.     

Protease inhibitors: synthesis of bacterial collagenase and matrix metalloproteinase inhibitors incorporating succinyl hydroxamate and iminodiacetic acid hydroxamate moieties

A series of succinyl hydroxamates/bishydroxamates as well as a new structural type of matrix metalloproteinase (MMP)/bacterial protease (BP) inhibitors, incorporating iminodiacetic (IDA) hydroxamate/bishydroxamate moieties, has been synthesized and tested for interaction with four vertebrate proteases, MMP-1, MMP-2, MMP-8 and MMP-9, and a BP, the collagenase isolated from Clostridium histolyticum (ChC). The new derivatives generally showed inhibition constants in the range of 8-62 nM against the five proteases mentioned above.     

High level of genetic differentiation in the marine isopod Sphaeroma terebrans (Crustacea Isopoda Sphaeromatidae) as inferred by mitochondrial DNA analysis

Sphaeroma terebrans Bate 1866 is a marine isopod belonging to the large family Sphaeromatidae, which normally colonises the aerial roots of the mangrove genus Rhizophora in tropical and subtropical areas. S. terebrans is part of a group of species whose complete life cycle occurs within the same mangrove wood. In this paper, we provide clear evidence of significant genetic differentiation among geographic populations of the taxon S. terebrans. The consistently low internal variation and the large interpopulation distances indicate that almost all the mitochondrial variation (cytochrome oxidase I) in S. terebrans is apportioned among populations rather than within them. The mean haplotype diversity (h) is 0.71%, and the mean nucleotide diversity (π) is 0.34%. The Minimum Spanning Tree (MST) reveals a complex pattern: three principal haplotype groups corresponding to the geographic locations investigated are distributed in a network. This suggests an ancient evolutionary history and very restricted gene flow between populations. The large genetic distances between the populations of S. terebrans could suggest that this taxon is not a single species but a species complex whose taxonomic status must be revaluated.     

Oxidative stress in diabetes-induced endothelial dysfunction involvement of nitric oxide and protein kinase C

Reactive oxygen species (ROS) formation plays a major role in diabetes-induced endothelial dysfunction, though the molecular mechanism(s) involved and the contribution of nitric oxide (NO) are still unclear. This study using bovine retinal endothelial cells was aimed at assessing (i) the role of oxygen-dependent vs. NO-dependent oxidative stress in the endothelial cell permeability alterations induced by the diabetic milieu and (ii) whether protein kinase C (PKC) activation ultimately mediates these changes. Superoxide, lipid peroxide, and PKC activity were higher under high glucose (HG) vs. normal glucose throughout the 30 d period. Nitrite/nitrate and endothelial NO synthase levels increased at 1 d and decreased thereafter. Changes in monolayer permeability to 125I-BSA induced by 1 or 30 d incubation in HG or exposure to advanced glycosylation endproduct were reduced by treatment with antioxidants or PKC inhibitors, whereas NO blockade prevented only the effect of 1 d HG. HG-induced changes were mimicked by a PKC activator, a superoxide generating system, an NO and superoxide donor, or peroxynitrite (attenuated by PKC inhibition), but not a NO donor. The short-term effect of HG depends on a combined oxidative and nitrosative stress with peroxynitrite formation, whereas the long-term effect is related to ROS generation; in both cases, PKC ultimately mediates permeability changes.     

An immunohistochemical and morphometric study on astrocytes and microvas culature in the human cerebral cortex

In this study, astrocytes and microvessels of the human cerebral cortex were analysed morphometrically with the aim of acquiring quantitative information on the glio-vascular relationships, considered to be of great importance in the formation and functioning of the blood--brain barrier. Immunohistochemistry for the astrocytic marker, glial fibrillary acidic protein, was used with a computerized image analysis system. The brain tissue was embedded using the progressive lowering of temperature method, and the image analyser was applied to semithin sections subjected to immunogold--silver staining and viewed by epipolarization microscopy. The results show that, in the human cerebral cortex, astrocytes cover 11.4% of the cortex area and that their perivascular processes are nearly as extensive as the vascular bed (0.8% versus 1.72% of the cortex area). These processes form a virtually continuous sheath around the vascular walls, only 11% of the vessel perimeter lacking this astrocytic glia covering. The present results, compared with previous unpublished data obtained by conventional immunocytochemical procedures on wax sections, indicate that low-temperature methods combined with gold--silver immunolabelling on semithin sections significantly improve the detection of immunoreactivity and the performance of the image analyser. This revised version was published online in November 2006 with corrections to the Cover Date.