Microclimate structures communities, predation and herbivory in the High Arctic

1. In a warming world, changes in climate may result in species-level responses as well as changes in community structure through knock-on effects on ecological interactions such as predation and herbivory. Yet, the links between these responses at different levels are still inadequately understood. Assessing how microclimatic conditions affect each of them at local scales provides information essential for understanding the consequences of macroclimatic changes projected in the future.2. Focusing on the rapidly changing High Arctic, we examine how a community based on a common resource species (avens, Dryas spp.), a specialist insect herbivore (Sympistis zetterstedtii) and natural enemies of lepidopteran herbivores (parasitoids) varies along a multidimensional microclimatic gradient. We ask (a) how parasitoid community composition varies with local abiotic conditions, (b) how the community-level response of parasitoids is linked to species-specific traits (koino- or idiobiont life cycle strategy and phenology) and (c) whether the effects of varying abiotic conditions extend to interaction outcomes (parasitism rates on the focal herbivore and realized herbivory rates).3. We recorded the local communities of parasitoids, herbivory rates on Dryas flowers and parasitism rates in Sympistis larvae at 20 sites along a mountain slope. For linking community-level responses to microclimatic conditions with parasitoid traits, we used joint species distribution modelling. We then assessed whether the same abiotic variables also affect parasitism and herbivory rates, by applying generalized linear and additive mixed models.4. We find that parasitism strategy and phenology explain local variation in parasitoid community structure. Parasitoids with a koinobiont strategy preferred high-elevation sites with higher summer temperatures or sites with earlier snowmelt and lower humidity. Species of earlier phenology occurred with higher incidence at sites with cooler summer temperatures or later snowmelt. Microclimatic effects also extend to parasitism and herbivory, with an increase in the parasitism rates of the main herbivore S. zetterstedtii with higher temperature and lower humidity, and a matching increase in herbivory rates.5. Our results show that microclimatic variation is a strong driver of local community structure, species interactions and interaction outcomes in Arctic ecosystems. In view of ongoing climate change, these results predict that macroclimatic changes will profoundly affect arctic communities

Salivary IgA to MAA-LDL and Oral Pathogens Are Linked to Coronary Disease

A large body of literature has established the link between periodontal disease and cardiovascular disease. Oxidized low-density lipoproteins (OxLDLs) have a crucial role in atherosclerosis progression through initiation of immunological response. Monoclonal IgM antibodies to malondialdehyde-modified low-density lipoprotein (MDA-LDL) and to malondialdehyde acetaldehyde-modified low-density lipoprotein (MAA-LDL) have been shown to cross-react with the key virulence factors of periodontal pathogens Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. We have previously shown that salivary IgA antibodies to MAA-LDL cross-react with P. gingivalis in healthy humans. In this study, we aim to assess whether oral mucosal immune response represented by salivary IgA to MAA-LDL and oral pathogens is associated with coronary artery disease (CAD). Also, the molecular mimicry through antibody cross-reaction between salivary IgA to MAA-LDL and oral pathogens was evaluated. The study subjects consisted of 451 patients who underwent a coronary angiography with no CAD (n = 133), stable CAD (n = 169), and acute coronary syndrome (ACS, n = 149). Elevated salivary IgA antibody levels to MAA-LDL, Rgp44 (gingipain A hemagglutinin domain of P. gingivalis), and Aa-HSP60 (heat shock protein 60 of A. actinomycetemcomitans) were discovered in stable-CAD and ACS patients when compared to no-CAD patients. In a multinomial regression model adjusted for known cardiovascular risk factors, stable CAD and ACS were associated with IgA to MAA-LDL (P = 0.016, P = 0.043), Rgp44 (P = 0.012, P = 0.004), Aa-HSP60 (P = 0.032, P = 0.030), Tannerella forsythia (P = 0.002, P = 0.004), Porphyromonas endodontalis (P = 0.016, P = 0.020), Prevotella intermedia (P = 0.038, P = 0.005), and with total IgA antibody concentration (P = 0.002, P = 0.016). Salivary IgA to MAA-LDL showed cross-reactivity with the oral pathogens tested in the study patients. The study highlights an association between salivary IgA to MAA-LDL and atherosclerosis. However, whether salivary IgA to MAA-LDL and the related oral humoral responses play a causal role in the development in the CAD should be elucidated in the future.Peer reviewe

Salivary IgA to MAA-LDL and Oral Pathogens Are Linked to Coronary Disease

A large body of literature has established the link between periodontal disease and cardiovascular disease. Oxidized low-density lipoproteins (OxLDLs) have a crucial role in atherosclerosis progression through initiation of immunological response. Monoclonal IgM antibodies to malondialdehyde-modified low-density lipoprotein (MDA-LDL) and to malondialdehyde acetaldehyde-modified low-density lipoprotein (MAA-LDL) have been shown to cross-react with the key virulence factors of periodontal pathogens Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. We have previously shown that salivary IgA antibodies to MAA-LDL cross-react with P. gingivalis in healthy humans. In this study, we aim to assess whether oral mucosal immune response represented by salivary IgA to MAA-LDL and oral pathogens is associated with coronary artery disease (CAD). Also, the molecular mimicry through antibody cross-reaction between salivary IgA to MAA-LDL and oral pathogens was evaluated. The study subjects consisted of 451 patients who underwent a coronary angiography with no CAD (n = 133), stable CAD (n = 169), and acute coronary syndrome (ACS, n = 149). Elevated salivary IgA antibody levels to MAA-LDL, Rgp44 (gingipain A hemagglutinin domain of P. gingivalis), and Aa-HSP60 (heat shock protein 60 of A. actinomycetemcomitans) were discovered in stable-CAD and ACS patients when compared to no-CAD patients. In a multinomial regression model adjusted for known cardiovascular risk factors, stable CAD and ACS were associated with IgA to MAA-LDL (P = 0.016, P = 0.043), Rgp44 (P = 0.012, P = 0.004), Aa-HSP60 (P = 0.032, P = 0.030), Tannerella forsythia (P = 0.002, P = 0.004), Porphyromonas endodontalis (P = 0.016, P = 0.020), Prevotella intermedia (P = 0.038, P = 0.005), and with total IgA antibody concentration (P = 0.002, P = 0.016). Salivary IgA to MAA-LDL showed cross-reactivity with the oral pathogens tested in the study patients. The study highlights an association between salivary IgA to MAA-LDL and atherosclerosis. However, whether salivary IgA to MAA-LDL and the related oral humoral responses play a causal role in the development in the CAD should be elucidated in the future.Peer reviewe

Consistent imprints of elevation, soil temperature and moisture on plant and arthropod communities across two subarctic landscapes

1. Factors shaping arthropod and plant community structure at fine spatial scales are poorly understood. This includes microclimate, which likely plays a large role in shaping local community patterns, especially in heterogeneous landscapes characterised by high microclimatic variability in space and in time.2. We explored differences in local microclimatic conditions and regional species pools in two subarctic regions: Kilpisj & auml;rvi in north-west Finland and Varanger in north-east Norway. We then investigated the relationship between fine-scale climatic variation and local community characteristics (species richness and abundance) among plants and arthropods, differentiating the latter into two groups: flying and ground-dwelling arthropods collected by Malaise and pitfall traps, respectively. Arthropod taxa were identified through DNA metabarcoding. Finally, we examined if plant richness can be used to predict patterns in arthropod communities.3. Variation in soil temperature, moisture and snow depth proved similar between regions, despite differences in absolute elevation. For each group of organisms, we found that about half of the species were shared between Kilpisj & auml;rvi and Varanger, with a quarter unique to each region.4. Plants and arthropods responded largely to the same drivers. The richness and abun-dance of both groups decreased as elevation increased and were positively correlated with higher soil moisture and temperature values. Plant species richness was a poor predictor of local arthropod richness, in particular for ground-dwelling arthropods.5. Our results reveal how microclimatic variation within each region carves pro-nounced, yet consistent patterns in local community richness and abundance out of a joint species pool

Reptile-like physiology in Early Jurassic stem-mammals

Despite considerable advances in knowledge of the anatomy, ecology and evolution of early mammals, far less is known about their physiology. Evidence is contradictory concerning the timing and fossil groups in which mammalian endothermy arose. To determine the state of metabolic evolution in two of the earliest stem-mammals, the Early Jurassic Morganucodon and Kuehneotherium, we use separate proxies for basal and maximum metabolic rate. Here we report, using synchrotron X-ray tomographic imaging of incremental tooth cementum, that they had maximum lifespans considerably longer than comparably sized living mammals, but similar to those of reptiles, and so they likely had reptilian-level basal metabolic rates. Measurements of femoral nutrient foramina show Morganucodon had blood flow rates intermediate between living mammals and reptiles, suggesting maximum metabolic rates increased evolutionarily before basal metabolic rates. Stem mammals lacked the elevated endothermic metabolism of living mammals, highlighting the mosaic nature of mammalian physiological evolution. Modern mammals are endothermic, but it has not been clear when this type of metabolism evolved. Here, Newham et al. analyse tooth and bone structure in Early Jurassic stem-mammal fossils to estimate lifespan and blood flow rates, which inform about basal and maximum metabolic rates, respectively, and show these stem-mammals had metabolic rates closer to modern ectothermic reptiles than to endothermic mammals.Peer reviewe

The effect of continuous ultrasound on chronic low back pain: protocol of a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Chronic non-specific low-back pain (LBP) is one of the most common and expensive musculoskeletal disorders in industrialized countries. Similar to other countries in the world, LBP is a common health and socioeconomic problem in Iran. One of the most widely used modalities in the field of physiotherapy for treating LBP is therapeutic ultrasound. Despite its common use, there is still inconclusive evidence to support its effectiveness in this group of patients. This randomised trial will evaluate the effectiveness of continuous ultrasound in addition to exercise therapy in patients with chronic LBP.</p> <p>Methods and design</p> <p>A total of 46 patients, between the ages 18 and 65 years old who have had LBP for more than three months will be recruited from university hospitals. Participants will be randomized to receive continuous ultrasound plus exercise therapy or placebo ultrasound plus exercise therapy. These groups will be treated for 10 sessions during a period of 4 weeks. Primary outcome measures will be functional disability and pain intensity. Lumbar flexion and extension range of motion, as well as changes in electromyography muscle fatigue indices, will be measured as secondary outcomes. All outcome measures will be measured at baseline, after completion of the treatment sessions, and after one month.</p> <p>Discussion</p> <p>The results of this trial will help to provide some evidence regarding the use of continuous ultrasound in chronic LBP patients. This should lead to a more evidence-based approach to clinical decision making regarding the use of ultrasound for LBP.</p> <p>Trial registration</p> <p>Netherlands Trial Register (NTR): <a href="http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=2251">NTR2251</a></p

The effect of massage on localized lumbar muscle fatigue

BACKGROUND: There is not enough evidence to support the efficacy of massage for muscle fatigue despite wide utilization of the modality in various clinical settings. This study investigated the influence of massage application on localized back muscle fatigue. METHODS: Twenty-nine healthy subjects participated in two experimental sessions (massage and rest conditions). On each test day, subjects were asked to lie in the prone position on a treatment table and perform sustained back extension for 90 seconds. Subjects then either received massage on the lumbar region or rested for a 5 minute duration, then repeated the back extension movement. The median frequency (MDF), mean power frequency (MNF), and root mean square (RMS) amplitude of electromyographic signals during the 90 second sustained lumbar muscle contraction were analyzed. The subjective feeling of fatigue was then evaluated using the Visual Analogue Scale (VAS). RESULTS: MDF and MNF significantly declined with time under all conditions. There was no significant difference in MDF, MNF or RMS value change between before and after massage, or between rest and massage conditions. There was a significant increase in fatigue VAS at the end of the 2(nd) back extension with rest condition. There was a significant difference in fatigue VAS change between massage and rest condition. CONCLUSIONS: A significant difference was observed between massage and rest condition on VAS for muscle fatigue. On EMG analysis, there were no significant differences to conclude that massage stimulation influenced the myoelectrical muscle fatigue, which is associated with metabolic and electrical changes

Rationale and design of a multicenter randomized controlled trial on a 'minimal intervention' in Dutch army personnel with nonspecific low back pain [ISRCTN19334317]

BACKGROUND: Researchers from the Royal Netherlands Army are studying the potential of isolated lumbar extensor training in low back pain in their working population. Currently, a randomized controlled trial is carried out in five military health centers in The Netherlands and Germany, in which a 10-week program of not more than 2 training sessions (10–15 minutes) per week is studied in soldiers with nonspecific low back pain for more than 4 weeks. The purpose of the study is to investigate the efficacy of this 'minimal intervention program', compared to usual care. Moreover, attempts are made to identify subgroups of different responders to the intervention. METHODS: Besides a baseline measurement, follow-up data are gathered at two short-term intervals (5 and 10 weeks after randomization) and two long-term intervals (6 months and one year after the end of the intervention), respectively. At every test moment, participants fill out a compound questionnaire on a stand-alone PC, and they undergo an isometric back strength measurement on a lower back machine. Primary outcome measures in this study are: self-assessed degree of complaints and degree of handicap in daily activities due to back pain. In addition, our secondary measurements focus on: fear of movement/(re-) injury, mental and social health perception, individual back extension strength, and satisfaction of the patient with the treatment perceived. Finally, we assess a number of potential prognostic factors: demographic and job characteristics, overall health, the degree of physical activity, and the attitudes and beliefs of the physiotherapist towards chronic low back pain. DISCUSSION: Although a substantial number of trials have been conducted that included lumbar extension training in low back pain patients, hardly any study has emphasized a minimal intervention approach comparable to ours. For reasons of time efficiency and patient preferences, this minimal sports medicine approach of low back pain management is interesting for the population under study, and possibly for comparable working populations with physical demanding job activities

Non-Water-Suppressed 1H MR Spectroscopy with Orientational Prior Knowledge Shows Potential for Separating Intra- and Extramyocellular Lipid Signals in Human Myocardium

Conditions such as type II diabetes are linked with elevated lipid levels in the heart, and significantly increased risk of heart failure; however, metabolic processes underlying the development of cardiac disease in type II diabetes are not fully understood. Here we present a non-invasive method for in vivo investigation of cardiac lipid metabolism: namely, IVS-McPRESS. This technique uses metabolite-cycled, non-water suppressed 1H cardiac magnetic resonance spectroscopy with prospective and retrospective motion correction. High-quality IVS-McPRESS data acquired from healthy volunteers allowed us to investigate the frequency shift of extramyocellular lipid signals, which depends on the myocardial fibre orientation. Assuming consistent voxel positioning relative to myofibres, the myofibre angle with the magnetic field was derived from the voxel orientation. For separation and individual analysis of intra- and extramyocellular lipid signals, the angle myocardial fibres in the spectroscopy voxel take with the magnetic field should be within ±24.5°. Metabolite and lipid concentrations were analysed with respect to BMI. Significant correlations between BMI and unsaturated fatty acids in intramyocellular lipids, and methylene groups in extramyocellular lipids were found. The proposed IVS-McPRESS technique enables non-invasive investigation of cardiac lipid metabolism and may thus be a useful tool to study healthy and pathological conditions

Iron-Responsive Olfactory Uptake of Manganese Improves Motor Function Deficits Associated with Iron Deficiency

Iron-responsive manganese uptake is increased in iron-deficient rats, suggesting that toxicity related to manganese exposure could be modified by iron status. To explore possible interactions, the distribution of intranasally-instilled manganese in control and iron-deficient rat brain was characterized by quantitative image analysis using T1-weighted magnetic resonance imaging (MRI). Manganese accumulation in the brain of iron-deficient rats was doubled after intranasal administration of MnCl2 for 1- or 3-week. Enhanced manganese level was observed in specific brain regions of iron-deficient rats, including the striatum, hippocampus, and prefrontal cortex. Iron-deficient rats spent reduced time on a standard accelerating rotarod bar before falling and with lower peak speed compared to controls; unexpectedly, these measures of motor function significantly improved in iron-deficient rats intranasally-instilled with MnCl2. Although tissue dopamine concentrations were similar in the striatum, dopamine transporter (DAT) and dopamine receptor D1 (D1R) levels were reduced and dopamine receptor D2 (D2R) levels were increased in manganese-instilled rats, suggesting that manganese-induced changes in post-synaptic dopaminergic signaling contribute to the compensatory effect. Enhanced olfactory manganese uptake during iron deficiency appears to be a programmed “rescue response” with beneficial influence on motor impairment due to low iron status