Distribution by Scientific Domains
Distribution within Medical Sciences

Kinds of Elevation

  • acute elevation
  • alt elevation
  • blood pressure elevation
  • ca2+ elevation
  • camp elevation
  • chronic elevation
  • co2 elevation
  • concomitant elevation
  • crp elevation
  • different elevation
  • enzyme elevation
  • flap elevation
  • floor elevation
  • fold elevation
  • high elevation
  • highest elevation
  • increasing elevation
  • intracellular ca2+ elevation
  • liver enzyme elevation
  • low elevation
  • lower elevation
  • m elevation
  • marked elevation
  • maximum elevation
  • mean elevation
  • membrane elevation
  • moderate elevation
  • persistent elevation
  • pressure elevation
  • relative elevation
  • segment elevation
  • significant elevation
  • sinus floor elevation
  • sinus membrane elevation
  • solar elevation
  • st elevation
  • st segment elevation
  • st-segment elevation
  • subsequent elevation
  • surface elevation
  • sustained elevation
  • table elevation
  • temperature elevation
  • transaminase elevation
  • transient elevation
  • troponin elevation
  • water elevation
  • water table elevation

  • Terms modified by Elevation

  • elevation acute coronary syndrome
  • elevation angle
  • elevation change
  • elevation data
  • elevation error
  • elevation gradient
  • elevation model
  • elevation models
  • elevation myocardial infarction
  • elevation procedure
  • elevation range
  • elevation surgery
  • elevation zone

  • Selected Abstracts


    Hiroko Negishi
    SUMMARY 1Prunes are recognized as a health food. They contain large amounts of phenolics and show high anti-oxidant activity. In this study, both hydroxyl radicals and superoxide anion were scavenged by prune extract in electron spin resonance (ESR) analysis. 2In angiotensin II challenged vascular smooth muscle cells (VSMCs) from stroke-prone spontaneously hypertensive rats (SHRSP), the reactive oxygen species (ROS) level was decreased in caffeic acid-treated cells compared with the control. 3After 5 weeks of prune extract treatment, the elevation of blood pressure in the prune extract-treated SHRSP was suppressed in comparison with the control group. 4Our findings suggest that prune extract may contribute to the primary prevention of cardiovascular diseases. [source]

    Elevation of gene expression for salmon gonadotropin-releasing hormone in discrete brain loci of prespawning chum salmon during upstream migration

    Takeshi Onuma
    Abstract Our previous studies suggested that salmon gonadotropin-releasing hormone (sGnRH) neurons regulate both final maturation and migratory behavior in homing salmonids. Activation of sGnRH neurons can occur during upstream migration. We therefore examined expression of genes encoding the precursors of sGnRH, sGnRH-I, and sGnRH-II, in discrete forebrain loci of prespawning chum salmon, Oncorhynchus keta. Fish were captured from 1997 through 1999 along their homing pathway: coastal areas, a midway of the river, 4 km downstream of the natal hatchery, and the hatchery. Amounts of sGnRH mRNAs in fresh frozen sections including the olfactory bulb (OB), terminal nerve (TN), ventral telencephalon (VT), nucleus preopticus parvocellularis anterioris (PPa), and nucleus preopticus magnocellularis (PM) were determined by quantitative real-time polymerase chain reactions. The amounts of sGnRH-II mRNA were higher than those of sGnRH-I mRNA, while they showed similar changes during upstream migration. In the OB and TN, the amounts of sGnRH mRNAs elevated from the coast to the natal hatchery. In the VT and PPa, they elevated along with the progress of final maturation. Such elevation was also observed in the rostroventral, middle, and dorsocaudal parts of the PM. The amounts of gonadotropin II, and somatolactin mRNAs in the pituitary also increased consistently with the elevation of gene expression for sGnRH. These results, in combination with lines of previous evidence, indicate that sGnRH neurons are activated in almost all the forebrain loci during the last phases of spawning migration, resulting in coordination of final gonadal maturation and migratory behavior to the spawning ground. © 2005 Wiley Periodicals, Inc. J Neurobiol, 2005 [source]

    Geostatistical analysis of ground-survey elevation data to elucidate spatial and temporal river channel change

    Adrian Chappell
    Abstract A digital elevation model (DEM) of a fluvial environment represented landform surface variability well and provided a medium for monitoring morphological change over time. Elevation was measured above an arbitrary datum using a ground-based three-dimensional tacheometric survey in two reaches of the River Nent, UK, in July 1998, October 1998 (after flood conditions) and June 1999. A detailed geostatistical analysis of the elevation data was used to model the spatial variation of elevation and to produce DEMs in each reach and for each survey period. Maps of the difference in elevation were produced and volumetric change was calculated for each reach and each survey period. The parameters of variogram models were used to describe the morphological character of each reach and to elucidate the linkages between process and the form of channel change operating at different spatial and temporal scales. The analysis of channel change on the River Nent shows the potential of geostatistics for investigating the magnitude and frequency of geomorphic work in other rivers. A flood modified the channel features, but low magnitude and high frequency flows rationalized the morphology. In spite of relatively small amounts of net flux the channel features changed as a consequence of the reworking of existing material. The blocking of chute entrances and redirection of the channel had a considerable effect on the behaviour of the channel. Such small changes suggested that the distributary system was sensitive to variation in sediment regime. Plots of the kriging variances against sampling intervals were used to quantify the temporal variation in sampling redundancy (ranging between ,11 per cent and +93 per cent). These curves illustrated the importance of bespoke sampling designs to reduce sampling effort by incorporating anisotropic variation in space and geomorphic information on flow regime. Variation in the nugget parameter of the variogram models was interpreted as sampling inaccuracy caused by variability in particle size and is believed to be important for future work on surface roughness. Copyright © 2003 John Wiley & Sons, Ltd. [source]

    Vigabatrin extracellular pharmacokinetics and concurrent ,-aminobutyric acid neurotransmitter effects in rat frontal cortex and hippocampus using microdialysis

    EPILEPSIA, Issue 2 2009
    Xin Tong
    Summary Purpose:, To investigate the pharmacokinetic interrelationship of vigabatrin in blood and the brain (frontal cortex vs. hippocampus) and to ascertain the relationship between brain extracellular vigabatrin concentrations and concurrent ,-aminobutyric acid (GABA) concentrations. Methods:, Sprague-Dawley rats were implanted with a jugular vein catheter for blood sampling, and microdialysis probes in the frontal cortex and hippocampus for extracellular fluid (ECF) sampling. Vigabatrin was administered intraperitoneally at two different doses (500 and 1,000 mg/kg), and blood and ECF were collected at timed intervals up to 8 h. Rats were freely moving and behaving. Vigabatrin (sera and ECF) and GABA (ECF) concentrations were measured with use of high performance liquid chromatography (HPLC). Results:, Vigabatrin concentrations in blood rose linearly and dose-dependently, and vigabatrin rapidly appeared in the brain as evidenced by the detection of vigabatrin in the ECF of both the frontal cortex and hippocampus at time of first sampling (15 min). However, frontal cortex concentrations were twofold greater than those of the hippocampus. Furthermore, GABA concentrations increased five-fold in the frontal cortex but were unaffected in the hippocampus. In addition, GABA concentrations began to increase approximately 3 h after vigabatrin administration at a time when vigabatrin concentrations were in exponential decline. Conclusions:, Vigabatrin distribution in the brain is region specific, with frontal cortex concentrations substantially greater than those seen in the hippocampus. Elevation of GABA concentrations did not reflect the concentration profile of vigabatrin but reflected its regional distribution. [source]

    Seizures Lead to Elevation of Intracranial Pressure in Children Undergoing Invasive EEG Monitoring

    EPILEPSIA, Issue 6 2007
    Aash K Shah
    Summary:,Purpose: To study the effects of intracranial subdural grid electrode placement and seizures on intracranial pressure (ICP) in children undergoing invasive EEG monitoring. Methods: Sixteen children with pharmacoresistant epilepsy who underwent two-stage epilepsy surgery with subdural grid placement were included in the study. The ICP was recorded at baseline and with each seizure prospectively. A variety of seizure parameters including type of seizure, length of seizure, extent of seizure spread, and number of subdural grid electrodes inserted were analyzed retrospectively and correlated with the change in ICP. Results: A total of 48 seizures in 16 children were studied. The mean baseline ICP correlated positively with age of the child. Generalized tonic,clonic seizures were associated with the highest rise in ICP. Similarly, ICP rise was associated with seizures involving more electrodes indicating a larger area of brain participating in the seizure. Conclusion: Seizures in general and generalized tonic,clonic seizures, in particular, increase ICP temporarily in patients who are undergoing invasive EEG monitoring with subdural grids. [source]

    Electrocardiographic ST-segment Elevation: Correct Identification of Acute Myocardial Infarction (AMI) and Non-AMI Syndromes by Emergency Physicians

    William J. Brady MD
    Abstract. Objective: To determine the emergency physician's (EP's) ability to identify the cause of ST-segment elevation (STE) in a hypothetical chest pain patient. Methods: Eleven electrocardiograms (ECGs) with STE were given to EPs; the patient in each instance was a 45-year-old male with a medical history of hypertension and diabetes mellitus with the chief complaint of chest pain. The EP was asked to determine the cause of the STE and, if due to acute myocardial infarction (AMI), to decide whether thrombolytic therapy (TT) would be administered (the patient had no contraindication to such treatment). Rates of TT administration were determined; appropriate TT administration was defined as that occurring in an AMI patient, while inappropriate TT administration was defined as that in the non-AMI patient. Results: Four hundred fifty-eight EPs completed the questionnaire; levels of medical experience included the following: postgraduate year 2-3, 193 (42%); and attending, 265 (58%). The overall rate of correct interpretation of the study ECGs was 94.9% (4,782 correct interpretations out of 5,038 instances). Acute myocardial infarction with typical STE, ventricular paced rhythm, and right bundle branch block were never misinterpreted. The remaining conditions were misinterpreted with rates ranging between 9% (left bundle branch block, LBBB) and 72% (left ventricular aneurysm, LVA). The overall rate of appropriate thrombolytic agent administration was 83% (1,525 correct administrations out of 1,832 indicated administrations). The leading diagnosis for which thrombolytic agent was given inappropriately was LVA (28%), followed by benign early repolarization (23%), pericarditis (21%), and LBBB without electrocardiographic AMI (5%). Thrombolytic agent was appropriately given in all cases of AMI except when associated with atypical STE, where it was inappropriately withheld 67% of the time. Conclusions: In this survey, EPs were asked whether they would give TT based on limited information (ECG). Certain syndromes with STE were frequently misdiagnosed. Emergency physician electrocardiographic education must focus on the proper identification of these syndromes so that TT may be appropriately utilized. [source]

    Antioxidant and anti-inflammatory activities of melanocortin peptides

    J. W. Haycock
    ,-Melanocyte-stimulating hormone (,-MSH) has previously been identified as a potent anti-inflammatory agent in various tissues including the skin. It operates by binding to the melanocortin-1 receptor (MC-1R) which results in the elevation of cyclic AMP. ,-MSH opposes the action of several proinflammatory cytokines including tumour necrosis factor-, (TNF-,). We have shown that ,-MSH can inhibit TNF-,-stimulated activation of nuclear factor-,B (NF-,B) in human cultured melanocytes, melanoma cells, keratinocytes, fibroblasts, Schwann cells and olfactory ensheathing cells. It also inhibits TNF-,-stimulated upregulation of intercellular adhesion molecule-1 (ICAM-1) in many of these cells and can inhibit peroxide-stimulated activation of glutathione peroxidase, suggesting an antioxidant role. ,-MSH is also able to stimulate intracellular calcium release in keratinocytes and fibroblasts (which do not readily show detectible cyclic AMP elevation) but only in the presence of PIA (an adenosine agonist). The carboxyl terminal tripeptides KPV/KP-D-V are reported to be the minimal sequences necessary to convey anti-inflammatory potential, but evidence on how they act is not fully known. Stable transfection of Chinese hamster ovary cells with MC-1R suggests that the KPV peptides operate by this receptor, at least by elevating intracellular calcium. Elevation of cyclic AMP by these tripeptides has not been detected in any cell type studied; however, calcium elevation can inhibit TNF-,-stimulated NF-,B activity (as for cyclic AMP). In conclusion, the MSH peptides convey anti-inflammatory and antioxidant activity in many cell types in skin and nerve, by counteracting proinflammatory cytokine signalling. The KPV peptides appear to act functionally via the MC-1R and can also elevate intracellular calcium. [source]


    ABSTRACT. The fifty-four Colorado Fourteeners,mountains more than 14,000 feet in elevation,were early symbols of westward expansion, mineral wealth, and wondrous scenery, and they are increasingly popular as environmental icons in place attachment at national, regional, state, and local scales. The symbolism of this contrived yet iconic collection of peaks is examined through the evolution of the Fourteener concept, the popularity of peakbagging, and the role of the Sawatch Range Fourteeners in creating a larger community identity. Elevation is the gatekeeper into the Fourteener club, in which a distinctive landscape iconography of shape, accessibility, and aesthetics reflects the role of idealized nature and mountains in place identity. [source]

    Domiciliary application of CryoCuff in severe haemophilia: qualitative questionnaire and clinical audit

    HAEMOPHILIA, Issue 4 2008
    A. I. D'YOUNG
    Abstract., The acute management of haemophilic bleeding episodesin the home setting is based on the concept of immediate factor replacement therapy and the PRICE regime , an acronym representing the concepts of Protection, Rest, Ice, Compression and Elevation [1,2]. Integral to this regime is the application of cold therapy, and yet little is known regarding the safe periods of application, or the relative safety of cryotherapy devices such as the CryoCuffÔ when used in the home setting by patients suffering from severe haemophilia and related bleeding disorders. This study examines the subjective patient response to the application of the CryoCuffÔ device in the home setting in terms of the effect on pain, joint swelling and the return to ,pre-bleed status' of the knee, ankle or elbow in patients with severe haemophilia A/B or type III von Willebrand's disease (VWD) immediately following haemarthrosis, and any potential adverse effects related to the device or recommended duration of application as stated in the PRICE guideline (Fig. 1). Twelve patients, either with severe haemophilia A/B or with VWD were recruited and asked to use the CryoCuffÔ device as part of the PRICE regime immediately following the onset of knee-, ankle- or elbow bleeds for the next one year. Each subject was then sent a qualitative questionnaire to determine subjective responses to the device. All patients reported that the application protocol was easy to follow, they were able to apply the device as per the PRICE regime and they were able to tolerate it for the recommended period. Whereas, all the patients felt that the device had a significant impact on alleviation of pain and return to pre-bleed status, 78% of the patients felt that the device led to a significant reduction in swelling around the affected joint. There was no conclusive evidence that the device resulted in any reduction in the amount of factor used to treat the acute bleeding episode, however, no patients reported any perceived delay in achieving haemostasis or required extra factor replacement therapy consequent to the usage of the device. No other adverse effects were reported by participants in this study. Figure 1. ,The qualitative participant questionnaire, given following 1 year of unsupervised use in the home setting immediately following the onset of the symptoms of haemarthroses. [source]

    Effect of tauroursodeoxycholic acid on endoplasmic reticulum stress,induced caspase-12 activation

    HEPATOLOGY, Issue 3 2002
    Qing Xie
    Activation of death receptors and mitochondrial damage are well-described common apoptotic pathways. Recently, a novel pathway via endoplasmic reticulum (ER) stress has been reported. We assessed the role of tauroursodeoxycholic acid (TUDCA) in inhibition of caspase-12 activation and its effect on calcium homeostasis in an ER stress-induced model of apoptosis. The human liver-derived cell line, Huh7, was treated with thapsigargin (TG) to induce ER stress. Typical morphologic changes of ER stress preceded development of apoptotic changes, including DNA fragmentation and cleavage of poly (adenosine diphosphate-ribose) polymerase (PARP), as well as activation of caspase-3 and -7. Elevation of intracellular calcium levels without loss of mitochondrial membrane potential (MMP) was shown using Fluo-3/Fura-red labeling and flow cytometry, and confirmed by induction of Bip/GRP78, a calcium-dependent chaperon of ER lumen. These changes were accompanied by procaspase-12 processing. TUDCA abolished TG-induced markers of ER stress; reduced calcium efflux, induction of Bip/GRP78, and caspase-12 activation; and subsequently inhibited activation of effector caspases and apoptosis. In conclusion, we propose that mitochondria play a secondary role in ER-mediated apoptosis and that TUDCA prevents apoptosis by blocking a calcium-mediated apoptotic pathway as well as caspase-12 activation. This novel mechanism of TUDCA action suggests new intervention methods for ER stress-induced liver disease. [source]

    Elevation of interleukin-18 in chronic hepatitis C: implications for hepatitis C virus pathogenesis

    IMMUNOLOGY, Issue 1pt2 2009
    Arpita Sharma
    Summary The outcome of hepatitis C virus (HCV) infection is determined by the interplay between the virus and the host immune response. Interleukin (IL)-18, an interferon-,-inducing factor, plays a critical role in the T helper type 1 (Th1) response required for host defence against viruses, and antibodies to IL-18 have been found to prevent liver damage in a murine model. The present study was conducted to investigate the possible role of IL-18 in the pathogenesis and persistence of HCV. IL-18 levels were measured in sera of 50 patients at various stages of HCV infection (resolved, chronic and cirrhosis) and compared with those of normal controls. IL-18 gene expression was studied in peripheral blood mononuclear cells (PBMC) from each group, and in liver biopsy tissue from patients with chronic hepatitis C. The mean levels of IL-18 in sera were markedly elevated in patients with chronic hepatitis and cirrhosis, and were reduced in patients with resolved HCV infection. The serum IL-18 concentrations were related to the Child,Pugh severity of liver disease in cirrhotic patients. There also existed a strong positive correlation of IL-18 levels with histological activity score and necrosis. IL-18 mRNA expression was significantly up-regulated in the PBMC of cirrhotic patients when compared with other groups, while in the liver, higher levels of IL-18 transcripts were expressed in patients with chronic hepatitis C. The results of our study indicate that IL-18 levels reflect the severity and activity of HCV infection, and may contribute to the pathogenesis and progression of liver disease associated with HCV. [source]

    Serum S100B in elderly patients with and without delirium

    Barbara C. van Munster
    Abstract Objective Elevation of S100B has been shown after various neurologic diseases with cognitive dysfunction. The aim of this study was to compare the serum level of S100B of patients with and without delirium and investigate the possible associations with different subtypes of delirium. Methods Acutely admitted medical patients aged 65 years or more were included from 2005 through 2008. Delirium was diagnosed by Confusion Assessment Method, delirium subtype by Delirium Symptom Interview and preexistent global cognitive function by the ,Informant Questionnaire on Cognitive Decline-short form'. S100B levels were determined in serum by electrochemiluminescence immunoassay. Results Samples of 412 patients were included, 91 during delirium, 35 after delirium and 286 of patients without delirium. Patients with delirium (31%) were significantly older, 81.5 versus 76.6 years (p,<,0.001) and experienced significantly more often preexistent cognitive and functional impairment (p,<,0.001). S100B level differed significantly (p,=,0.004) between the three groups: median 0.07,,g/L (inter-quartile ranges: 0.05,0.14,,g/L) during delirium, 0.12,,g/L (0.05,0.29,,g/L) after delirium and 0.06,,g/L (0.03,0.10,,g/L) in patients without delirium. Combining the impact of cognitive impairment, infection and age on S100B, highest S100B was observed in the oldest patients after delirium with preexistent cognitive impaired and infection. Delirium subtype and S100B level were not significantly correlated. Conclusion Higher S100B levels were found in patients with delirium than in patients without delirium, with highest levels of S100B in samples taken after delirium. Future studies are needed to elucidate the mechanism responsible for the increase of S100B and the possible association with long term cognitive impairment. Copyright © 2009 John Wiley & Sons, Ltd. [source]

    Predictors of Interleukin-6 Elevation in Older Adults

    Shuhan Zhu BS
    OBJECTIVES: To investigate the characteristics of older adults who develop high interleukin-6 (IL-6) levels at 3-year follow-up. DESIGN: Population-based study of adults living in Tuscany, Italy. SETTING: Community. PARTICIPANTS: Adults aged 65 and older and were selected for this study. Of 1,155 baseline participants aged 65 and older, 741 had IL-6 measurements at baseline and 3-year follow-up. MEASUREMENTS: The uppermost quartile of IL-6 was used as the threshold for defining high IL-6 (,4.18 pg/mL). Serum IL-6 levels were assessed using enzyme immunoassay. RESULTS: Of the 581 participants with IL-6 levels less than 4.18 pg/mL at baseline, 106 (18.2%) had developed high IL-6 at follow-up. Although women had lower IL-6 levels at baseline than men, the risk of developing high IL-6 did not differ according to sex. High adiposity, defined as a body mass index of 30.0 kg/m2 or higher (odds ratio (OR)=2.63, 95% confidence interval (CI)=1.40,4.96), and large waist circumference, defined as 102 cm or greater for men and 88 cm or greater for women (OR=2.05, 95% CI=1.24,3.40), were significant predictors of developing high IL-6 at follow-up. Other significant predictors were presence of three or more chronic diseases (OR=3.66, 95% CI=1.54,8.70), higher baseline IL-6 (OR=1.82, 95% CI=1.39,2.38) and higher white blood cell count (OR=1.24, 95% CI=1.06,1.45). Faster walking speed associated with decreased risk of progressing to elevated IL-6 (OR=0.83, 95% CI=0.74,0.92). CONCLUSION: Older age, greater adiposity, slower walking speed, higher disease burden, and higher white blood cell count were associated with greater risk of IL-6 elevation over a 3-year period. Future research should target older adults with these characteristics to prevent progression to a proinflammatory state. [source]

    Elevation and forest clearing effects on foraging differ between surface , and subterranean , foraging army ants (Formicidae: Ecitoninae)

    Anjali Kumar
    Summary 1Forest fragmentation often results in a matrix of open areas mixed with patches of forest. Both biotic and abiotic factors can affect consumer species' ability to utilize the altered habitat, especially for species that range over large areas searching for prey. 2Army ants (Formicidae: Ecitoninae) are highly mobile top predators in terrestrial Neotropical ecosystems. Army ant foraging behaviour is influenced by forest clearing at lowland sites, and clearing can reduce army ant population persistence. 3Because high temperatures are implicated in hindering above-ground army ant foraging, we predicted that forest clearing effects on army ant foraging would be reduced at higher (cooler) elevations in montane forest. We also predicted that subterranean foraging, employed by some army ant species, would buffer them from the negative effects of forest clearing. 4We quantified the foraging rates of above-ground and underground foraging army ants at eight sites along an elevational gradient from 1090 to 1540 m a.s.l. We asked whether these two foraging strategies cause a difference in the ability of army ants to forage in open matrix areas relative to elevationally matched forested habitats, and whether elevation predicts open area vs. forest foraging rate differences. 5As predicted, army ants that forage above-ground had lower foraging rates in open areas, but the open area vs. forest difference declined with elevation. In contrast, underground foragers were not affected by habitat type, and underground foraging rates increased with elevation. Ground surface temperatures were higher in open areas than forested areas. Temperatures declined with elevation, and temperature differences between open and forested areas decreased with elevation. 6We conclude that army ants that forage above-ground may be restricted to forested areas due to a thermal tolerance threshold, but that they are released from this limitation at higher elevations. We further suggest that underground foraging permits some army ants to persist within modified landscapes. Our findings have implications for the effects of habitat modification and climate change on these top predators. [source]

    The effect of environmental diversification on species diversification in New Caledonian caddisflies (Insecta: Trichoptera: Hydropsychidae)

    Marianne Espeland
    Abstract Aim, To test whether environmental diversification played a role in the diversification of the New Caledonian Hydropsychinae caddisflies. Location, New Caledonia, south-west Pacific. Methods, The phylogeny of the New Caledonian Hydropsychinae caddisflies was hypothesized using parsimony and Bayesian methods on molecular characters. The Bayesian analysis was the basis for a comparative analysis of the correlation between phylogeny and three environmental factors: geological substrate (ultrabasic, non-ultrabasic), elevation and precipitation. Phylogenetic divergence times were estimated using a relaxed clock method, and environmental factors were mapped onto a lineage-through-time plot to investigate the timing of environmental diversification in relation to species radiation. The correlation between rainfall and elevation was tested using independent contrasts, and the gamma statistic was calculated to infer the diversification pattern of the group. Results, The diversification of extant Orthopsyche,Caledopsyche species began in the Middle,Late Oligocene, when much of the island of New Caledonia was covered by ultrabasic substrate and mountain forming was prevalent. Most lineages originated in the Middle,Late Miocene, a period associated with long-term climate oscillation. Optimization of environmental factors on the phylogeny demonstrated that the New Caledonian Hydropsychinae group adapted to ultrabasic substrate early in its evolutionary history. The clade living mostly on ultrabasic substrate was far more species-rich than the clade living mostly on non-ultrabasic substrate. Elevation and rainfall were significantly correlated with each other. The lineage-through-time plot revealed that the main environmental diversification preceded species diversification. A constant speciation through time was rejected, and the negative gamma indicates that most of the diversification occurred early in the history of the clade. According to the inferred phylogeny, the genus Orthopsyche McFarlane is a synonym under Caledopsyche Kimmins, and Abacaria caledona Oláh & Barnard should also be included in Caledopsyche. Main conclusions, The age of the radiation does not support a vicariance origin of New Caledonian Hydropsychinae caddisflies. Environmental diversification pre-dates lineage diversification, and thus environmental heterogeneity potentially played a role in the diversification of the group, by providing a variety of fragmented habitats to disperse into, promoting speciation. The negative gamma indicates that the speciation rate slowed as niches started to fill. [source]

    Patterns of species richness on very small islands: the plants of the Aegean archipelago

    Maria Panitsa
    Abstract Aim, To investigate the species,area relationship (SAR) of plants on very small islands, to examine the effect of other factors on species richness, and to check for a possible Small Island Effect (SIE). Location, The study used data on the floral composition of 86 very small islands (all < 0.050 km2) of the Aegean archipelago (Greece). Methods, We used standard techniques for linear and nonlinear regression in order to check several models of the SAR, and stepwise multiple regression to check for the effects of factors other than area on species richness (,habitat diversity', elevation, and distance from nearest large island), as well as the performance of the Choros model. We also checked for the SAR of certain taxonomic and ecological plant groups that are of special importance in eastern Mediterranean islands, such as halophytes, therophytes, Leguminosae and Gramineae. We used one-way anova to check for differences in richness between grazed and non-grazed islands, and we explored possible effects of nesting seabirds on the islands' flora. Results, Area explained a small percentage of total species richness variance in all cases. The linearized power model of the SAR provided the best fit for the total species list and several subgroups of species, while the semi-log model provided better fits for grazed islands, grasses and therophytes. None of the nonlinear models explained more variance. The slope of the SAR was very high, mainly due to the contribution of non-grazed islands. No significant SIE could be detected. The Choros model explained more variance than all SARs, although a large amount of variance of species richness still remained unexplained. Elevation was found to be the only important factor, other than area, to influence species richness. Habitat diversity did not seem important, although there were serious methodological problems in properly defining it, especially for plants. Grazing was an important factor influencing the flora of small islands. Grazed islands were richer than non-grazed, but the response of their species richness to area was particularly low, indicating decreased floral heterogeneity among islands. We did not detect any important effects of the presence of nesting seabird colonies. Main conclusions, Species richness on small islands may behave idiosyncratically, but this does not always lead to a typical SIE. Plants of Aegean islets conform to the classical Arrhenius model of the SAR, a result mainly due to the contribution of non-grazed islands. At the same time, the factors examined explain a small portion of total variance in species richness, indicating the possible contribution of other, non-standard factors, or even of stochastic effects. The proper definition of habitat diversity as pertaining to the taxon examined in each case is a recurrent problem in such studies. Nevertheless, the combined effect of area and a proxy for environmental heterogeneity is once again superior to area alone in explaining species richness. [source]

    Brugada Syndrome with ST-Segment Elevation in the Lateral Leads

    No abstract is available for this article. [source]

    Comparative Pharmacology of Guinea Pig Cardiac Myocyte and Cloned hERG (IKr) Channel

    Introduction: This study used whole-cell, patch clamp techniques on isolated guinea pig ventricular myocytes and HEK293 cells expressing cloned human ether-a-go-go-related gene (hERG) to examine the action of drugs causing QT interval prolongation and torsades de pointes (TdP) in man. Similarities and important differences in drug actions on cardiac myocytes and cloned hERG IKr channels were established. Qualitative actions of the drugs on cardiac myocytes corresponded with results obtained from Purkinje fibers and measurement of QT interval prolongation in animal and human telemetry studies. Methods and Results: Adult guinea pig ventricular myocytes were isolated by enzymatic digestion. Cells were continuously perfused with Tyrode's solution at 33,35°C. Recordings were made using the whole-cell, patch clamp technique. Action potentials (APs) were elicited under current clamp. Voltage clamp was used to study the effect of drugs on IKr (rapidly activating delayed rectifier potassium current), INa (sodium current), and ICa (L-type calcium current). Dofetilide increased the myocyte action potential duration (APD) in a concentration-dependent manner, with a pIC50 of 7.3. Dofetilide 1 ,M elicited early afterdepolarizations (EADs) but had little affect on ICa or INa. E-4031 increased APD in a concentration-dependent manner, with a pIC50 of 7.2. In contrast, 10 ,M loratadine, desloratadine, and cetirizine had little effect on APD or IKr. Interestingly, cisapride displayed a biphasic effect on myocyte APD and inhibited ICa at 1 ,M. Even at this high concentration, cisapride did not elicit EADs. A number of AstraZeneca compounds were tested on cardiac myocytes, revealing a mixture of drug actions that were not observed in hERG currents in HEK293 cells. One compound, particularly AR-C0X, was a potent blocker of myocyte AP (pIC50 of 8.4). AR-C0X also elicited EADs in cardiac myocytes. The potencies of the same set of drugs on the cloned hERG channel also were assessed. The pIC50 values for dofetilide, E-4031, terfenadine, loratadine, desloratadine, and cetirizine were 6.8, 7.1, 7.3, 5.1, 5.2, and <4, respectively. Elevation of temperature from 22 to 35°C significantly enhanced the current kinetics and amplitudes of hERG currents and resulted in approximately fivefold increase in E-4031 potency. Conclusion: Our study demonstrates the advantages of cardiac myocytes over heterologously expressed hERG channels in predicting QT interval prolongation and TdP in man. The potencies of some drugs in cardiac myocytes were similar to hERG, but only myocytes were able to detect important changes in APD characteristics and display EADs predictive of arrhythmia development. We observed similar qualitative drug profiles in cardiac myocytes, dog Purkinje fibers, and animal and human telemetry studies. Therefore, isolated native cardiac myocytes are a better predictor of drug-induced QT prolongation and TdP than heterologously expressed hERG channels. Isolated cardiac myocytes, when used with high-throughput patch clamp instruments, may have an important role in screening potential cardiotoxic compounds in the early phase of drug discovery. This would significantly reduce the attrition rate of drugs entering preclinical and/or clinical development. The current kinetics and amplitudes of the cloned hERG channel were profoundly affected by temperature, significantly altering the potency of one drug (E-4031). This finding cautions against routine drug testing at room temperature compared to physiologic temperature when using the cloned hERG channel. [source]

    Effect of Gender on Atrial Electrophysiologic Changes Induced by Rapid Atrial Pacing and Elevation of Atrial Pressure

    Atrial Electrical Remodeling.Introduction: The incidence of atrial fibrillation is greater in men than in women, but the reasons for this gender difference are unclear. The purpose of this study was to evaluate the effects of gender on the atrial electrophysiologic effects of rapid atrial pacing and an increase in atrial pressure. Methods and Results: Right atrial pressure and effective refractory period (ERP) were measured during sinus rhythm and during atrial and simultaneous AV pacing at a cycle length of 300 msec in 10 premenopausal women, 11 postmenopausal women, and 24 men. The postmenopausal women were significantly older than the premenopausal women (61 ± 8 years vs 34 ± 10 years; P < 0.01). During sinus rhythm, mean atrial ERP in premenopausal women was shorter (211 ± 19 msec) than in postmenopausal women and age-matched men (242 ± 18 msec and 246 ± 34 msec, respectively; P < 0.05). Atrial ERPs in all patients shortened significantly during atrial and simultaneous AV pacing. However, the degree of shortening during atrial pacing (43 ± 8 msec vs 70 ± 20 msec and 74 ± 21 msec; P < 0.05) and during simultaneous AV pacing (48 ± 16 msec vs 91 ± 27 msec and 84 ± 26 msec; P < 0.05) was significantly less in premenopausal women than in postmenopausal women or age-matched men. Conclusion: The results of this study demonstrate a significant gender difference in atrial electrophysiologic changes in response to rapid atrial pacing and an increase in atrial pressure. The effect of menopause on the observed changes suggests that the gender differences may be mediated by the effects of estrogen on atrial electrophysiologic properties. [source]

    Transient ST Segment Elevation in Right Precordial Leads Induced by Psychotropic Drugs: Relationship to the Brugada Syndrome

    Psychotropic Drugs and ST Segment Elevation. Transient ST segment elevation in right precordial leads with use of psychotropic drugs is reported in two cases of overdose and one case of therapeutic administration. Flecainide did not reproduce ST segment elevation. The relationship of these abnormalities to the Brugada syndrome and the electrophysiologic hypothesis are discussed. [source]

    Clinical Characteristics of Patients With Spontaneous or Inducible Ventricular Fibrillation Without Apparent Heart Disease Presenting with J Wave and ST Segment Elevation in Inferior Leads

    Ventricular Fibrillation with J Wave in Inferior Leads. Introduction: The clinical characteristics of three patients with spontaneous or inducible ventricular fibrillation (VF) without apparent heart disease, who presented with J wave and ST segment elevation in inferior leads, are described. Methods and Results: All patients were male and experienced syncope. Their symptoms occurred at night or early in the morning. Holter ECG revealed infrequent premature ventricular complexes. Injection with disopyramide 2 mg/kg augmented ST segment elevation. Conclusion: These characteristics were very similar to those of patients with Brugada syndrome. These three patients with these specific features might have a variant of Brugada syndrome. [source]

    Sharing natural resources: mountain gorillas and people in the Parc National des Volcans, Rwanda

    Hein Van Gils
    Abstract The compatibility of natural resource use by people and mountain gorillas (Gorilla beringei beringei) within the Parc National des Volcans was studied. The distribution of gorillas was modelled using a Maximum Entropy algorithm. Biophysical predictor variables were trained with daily GPS locations of gorillas during 2006. Elevation, as a climate surrogate, was the best predictor (58%) of the occurrence of gorillas. The mid-altitudes (2500,3500 m a.s.l.) contained the bulk of the gorilla groups. Incoming solar radiation, as proxy for comfortable nesting sites, was the second best predictor (17%). Vegetation types, as foliage provider, (13%) and slope steepness for providing security (12%) were contributing predictors. The modelled and actual gorilla distributions were together overlaid with people's resource use in the park. Both people and gorillas were congregated in the areas identified as most suitable for gorillas. However, within these areas spatial segregation was found between human natural resource-users and gorillas. Therefore, the number of gorillas is likely to be limited by the human natural resource use within the park. A perimeter fence, the introduction of community-based natural resource management, and a buffer zone are discussed as short-, medium- and long-term mitigation measures. Résumé Nous avons étudié la compatibilité entre l'utilisation des ressources naturelles par les hommes et la présence des gorilles de montagnes (Gorilla beringei beringei) dans le Parc National des Volcans. La distribution des gorilles fut modélisée en utilisant un algorithme d'entropie maximum. En 2006, on a testé des variables de prédicteurs biophysiques, avec localisation quotidienne des gorilles par GPS. L'altitude, substitut du climat, était le meilleur prédicteur (58%) de la présence de gorilles. La plupart des groupes de gorilles se trouvaient à des altitudes moyennes (2 500,3 000 m). Le rayonnement solaire, condition de sites de nidification confortables, étaient le deuxième prédicteur (17%). Les types de végétation, fournisseurs de feuilles (13%) et l'importance des pentes, gage de sécurité (12%) étaient des prédicteurs contributeurs. Les distributions modélisées et réelles des gorilles furent superposées à l'utilisation des ressources du parc par les gens. Les hommes et les gorilles étaient rassemblés dans les zones identifiées comme les plus favorables pour les gorilles. Cependant, dans ces zones, on a trouvé une ségrégation spatiale entre les utilisateurs humains des ressources naturelles et les gorilles. Le nombre de gorilles risque donc d'être limité par l'utilisation humaine des ressources naturelles dans le parc. L'on discute de la pose d'une clôture en périphérie, de l'introduction d'une gestion communautaire des ressources naturelles et de la définition d'une zone tampon comme mesures de mitigation à court, moyen et long terme. [source]

    Elephant distribution around a volcanic shield dominated by a mosaic of forest and savanna (Marsabit, Kenya)

    Shadrack M. Ngene
    Abstract We investigated the factors that influenced the distribution of the African elephant around a volcanic shield dominated by a mosaic of forest and savanna in northern Kenya. Data on elephant distribution were acquired from four female and five bull elephants, collared with satellite-linked geographical positioning system collars. Based on the eigenvalues (variances) of the correlation matrix, the six factors that contributed significantly to high total variances were distance from drinking water (24%), elevation (15%), shrubland (10%), forest (9%), distance from settlements (8%) and distance from minor roads (7%), contributing to 73% in the observed variation of the elephant distribution. The elephants were found at high forested elevations during the dry season but they moved to the lowlands characterized by shrubland during the wet season. Elevation acts as a proxy for the vegetation structure. The presence of elephants near permanent water points (13%) and seasonal rivers (11%) during the dry and wet seasons, respectively, demonstrates that water is the most important determinant of their distribution throughout the year. We conclude that the distribution of elephants in Marsabit Protected Area and its adjacent areas is influenced mainly by drinking water and vegetation structure. Résumé Nous avons étudié les facteurs qui influencent la distribution de l'éléphant africain autour d'un bouclier volcanique dominé par une mosaïque de forêt et de savane dans le nord du Kenya. Les données sur la distribution des éléphants furent acquises grâce à quatre femelles et cinq mâles équipés de colliers radio avec GPS par satellite. En se basant sur les valeurs propres (variances) de la matrice de corrélation, les six facteurs qui ont contribué significativement à de fortes variances totales étaient la distance par rapport à l'eau (24%), l'élévation (15%), la savane arbustive (10%), la forêt (9%), la distance par rapport à des installations (8%) et celle par rapport à des routes peu importantes (7%), qui contribuent donc ensemble à 73% de la variation observée dans la distribution de l'éléphant. Des éléphants se trouvaient sur de hautes élévations forestières pendant la saison sèche, mais ils se déplaçaient vers les terrains de basse altitude caractérisés par des broussailles pendant la saison des pluies. L'élévation sert de proxy à la structure de la végétation. La présence d'éléphants près des points d'eau permanents (13%) et des rivières saisonnières (11%) pendant la saison sèche et la saison des pluies respectivement montre que l'eau est le déterminant le plus important de leur distribution tout au long de l'année. Nous concluons que la distribution des éléphants dans la Marsabit Protected Area et dans les zones adjacentes est influencée principalement par la disponibilité de l'eau et la structure de la végétation. [source]

    A panel of multiple markers associated with chronic systemic inflammation and the risk of atherogenesis is detectable in asthma and chronic obstructive pulmonary disease

    Tsu-Lan Wu
    Abstract Asthma and chronic obstructive pulmonary disease (COPD) are both lung diseases involving chronic inflammation of the airway. The injury is reversible in asthma whereas it is mostly irreversible in COPD. Both patients of asthma and COPD are known at risk for cardiovascular disease (CVD) and type 2 diabetes (T2DM), nephropathy, and cancer. We measured multiple risk markers for atherogenesis in 55 patients with asthma and 62 patients with COPD. We wanted to know whether risk markers for atherogenesis corresponding to sequence of events of chronic inflammation were also detectable in the airway inflammatory diseases. Elevation of almost all markers involving inflammation of the endothelial cells in the coronary artery were detectable in asthma and COPD involving the inflammation of the epithelial cell lining of the airway. Both the level and % elevation of all markers were found mostly higher in COPD, the more severe form of the lung disease. We believe that these markers are useful for predicting risk of developing clinical complications such as CVD. J. Clin. Lab. Anal. 21:367,371, 2007. © 2007 Wiley-Liss, Inc. [source]

    Mexican Jay social group size varies with habitat in northeastern Mexico

    Nirmal K. Bhagabati
    ABSTRACT We evaluated the hypothesis that social group size in Mexican Jays (Aphelocoma ultramarina) varies with habitat structure. We counted the social group size of Mexican Jays over a range of elevations and forest types in a single mountain range in northern Mexico (Sierra El Carmen, Coahuila). Group size increased significantly with elevation, in contrast to a population of Mexican Jays in Arizona that showed no such trend in another study. Among the vegetation variables measured, those relating to size of pines and oaks were especially important in explaining variation in group size. Because acorns and pine nuts are a major part of the diet of Mexican Jays, sites with larger oaks and pines may produce larger nut crops and support larger groups of jays. Elevation did not significantly explain variance in group size after taking vegetation into account. We compared group size and habitat variation across different parts of the geographic range of Mexican Jays. Our analysis indicates that variation of social group size in Mexican Jays is influenced by habitat quality at both local and geographic scales. Detailed studies on habitat structure and demographics of this population are needed to further clarify aspects of habitat quality important to these jays, and the mechanisms by which variation in social structure is maintained. SINOPSIS Evaluamos la hipótesis en donde se indica que el tamaño de los grupos en el Azulejón Mexicano (Aphelocoma ultramarina) varía con la estructura del hábitat. Determinamos el tamaño del grupo social a través de elevaciones variadas y tipos de bosques a lo largo de una cordillera en la Sierra El Carmen, Coahuila, del norte de México. El tamaño del grupo incremento significativamente con la elevación, en contraste con una población de azulejones estudiada en Arizona. Entre las variables medidas en la vegetación, encontramos unas relacionadas al tamaño de los pinos y los robles que fueron especialmente importante en la explicación del tamaño de los grupos. Dado el caso de que las semillas y nueces son un componente principal en la dieta de las aves, los lugares con árboles de mayor tamaño pudieran producir más alimento y a su vez sostener grupos mayores de azulejones. La elevación no explicó significativamente la variación en el tamaño de los grupos, una vez incluido en el análisis la vegetación. Comparamos tamaño de grupos y la variación en hábitat a través de diferentes partes de la distribución geográfica del ave. Nuestro análisis indica que la variación de tamaño de los grupos esta influenciada por la calidad del hábitat tanto al nivel local como geográfico. Estudios detallados en la estructura del hábitat y estudios demográficos son necesarios para determinar el mecanismo a través del cual se mantiene la variación en grupos. [source]

    Supplementation of Energy-restricted Diets with Coconut Oil Improves Nitrogen Balance Without Elevation of Blood Cholesterol Levels

    M.Z.A. Nomani
    ABSTRACT: Thirty-six growing male rats were fed 1 of 6 diets for 4 wk: (1) semipurified basal diet (B) with 10% corn oil, 21.6% fat calories (FC), 14 g B diet/day; (2) B + 1 g of coconut oil (32% FC); (3) B + 1 g olive oil; (4) B + 1 g corn oil; (5) B + 2.25 g starch (18.7% FC); and (6) B + 2 g coconut oil (40% FC). Weight gain and nitrogen balance were higher (p < 0.;05) for supplemented diet groups. Serum cholesterol and triglyceride levels were not different (p > 0.05). It may be suggested that under restricted energy intake conditions (67% to 75% of the requirements) a high-fat diet (32% to 40% fat calories), including a diet rich in highly saturated coconut oil, can serve as a source of energy and contribute to improved nitrogen balance, without elevating blood cholesterol levels. [source]

    Application of a Cardiac Arrest Score in Patients with Sudden Death and ST Segment Elevation for Triage to Angiography and Intervention

    The aim of this study was to test a previously validated, prognostic, cardiac arrest score in patients with ST segment elevation acute myocardial infarction (AMI) who suffereda witnessed cardiac arrest and survived to emergency department admission. A consecutive series constructed retrospectively from a sudden death database (n= 22) of patients with ST segment elevation AMI resuscitated from cardiac arrest underwent angiography and angioplasty of the culprit vessel within 24 hours of presentation. A cardiac arrest score was assigned to each case by explicit criteria present on evaluation. Primary outcomes were survival to hospital discharge and the degree of neurological recovery during the hospitalization. All patients underwent successful coronary angioplasty and 77% received adjunctive intraaortic balloon counterpulsation. The overall rate of survival to discharge was 41%. For cardiac arrest scores of 0, 1, 2, and 3, respectively, the rates of neurologic recovery were 0 (0%) of 4 (95% CI 0,53%), 3 (50%) of 6 (95% CI 15,85%), 2 (67%) of 3 (95% CI 13,98%), and 9 (100%) of 9 (95% CI 72,100%), and the rates of survival to discharge were 0(0%) of 4, (95% CI 0,53%), 2 (33%) of 6 (95% CI 6,74%), 2 (67%) of 3 (95% CI 13,98%), and 9 (100%) of 9 (95% CI 72,100%), P<0.01 for both outcomes over ascending scores. These results suggest appropriate patients for primary angioplasty after cardiac arrest are those with ST segment elevation AMI and an emergency department cardiac arrest score of ,2, thus predicting a11 (92%) of 12 (95% CI 65,100%) chance of survival to discharge. [source]

    Elevation of cyclin D1 following trimethyltin induced hippocampal neurodegeneration

    R. N. Wine
    Previous work has suggested that a major contributor to neuronal cell death is the aberrant induction of the cell cycle process, as indicated by an up-regulation of cyclin D. In order to examine the temporal and spatial relationship of cyclin D in a model of acute neurodegeneration, the hippocampal toxicant, trimethyltin (TMT; 2.0 mg/kg), was administered to 21-day old CD,1 male mice and the level and cellular localization of cyclin D1 examined. Within 24 h following TMT, dentate granule cells of the hippocampus showed evidence of neuronal necrosis resulting in severe cell loss over a 3-day period. The pyramidal cell layer was spared with only sparse punctate neuronal necrosis. Microglia response was seen at 72 h with ameboid microglia present in the dentate and ramified microglia present in the pyramidal cell layer, contributing to the elevation seen in TNF-alpha mRNA levels. A transient elevation was seen in mRNA levels for cyclin D1 over 48,72 h post-TMT. Immunohistochemistry demonstrated a transient increase in staining for cyclin D1 in CA1 pyramidal neurons as early as 24 h. Punctate staining occurred in neurons throughout the dentate at 48 h. BrdU positive cells were present along the inner blades of the dentate in control animals. Following TMT exposure, an increase was seen in both the number of neurons stained and a diffusion of the staining pattern into the full dentate region. Thus, in TMT-induced neurodegeneration, cyclin D1 is not expressed in the vulnerable neurons but rather in neurons spared from degeneration. This expression pattern appears to not be linked to an increase in the cellular processes for proliferation as the majority of BrdU positive cells were present in the region of neuronal damage. [source]

    Iso-S -petasin, a hypotensive sesquiterpene from Petasites formosanus, depresses cardiac contraction and intracellular Ca2+ transients in adult rat ventricular myocytes

    Lucy B. Esberg
    ABSTRACT Petasites formosanus is an indigenous species of the medicinal plant Petasites which has been used to treat hypertension. Both S -petasin and its isoform iso-S -petasin have been shown to be the effective ingredients in P. formosanus. However, their effect on heart function has not been revealed. This study was to examine the effect of iso-S -petasin on cardiac contractile function at the myocyte level. Ventricular myocytes were isolated from adult rat hearts and were stimulated to contract at 0.5 Hz under 1.0 mm extracellular Ca2+. Contractile properties were evaluated using an lonOptix MyoCam system including peak shortening (PS), time to PS (TPS), time to 90% re-lengthening (TR90) and maximal velocity of shortening/re-lengthening (±dL/dt). Intracellular Ca2+ properties were assessed by fura-2 and presented as Ca2+ -induced Ca2+ release (CICR) and intracellular Ca2+ decay. Acute application of iso-S -petasin (10,7 to 10,4 M) elicited a concentration-dependent inhibition in PS and CICR, with maximal inhibitions of 51.0% and 31.0%, respectively. iso-S -petasin also induced a concentration-dependent inhibition of ± dL/dt without affecting TPS, TR90, baseline intracellular Ca2+ level or intracellular Ca2+ decay. Elevation of extracellular Ca2+ from 1.0 mm to 2.7 mm significantly antagonized the iso-S -petasin-induced depression in PS and CICR. These results demonstrated a direct depressant action of iso-S -petasin on ventricular contraction, which may work in concert with its antihypertensive action to reduce the cardiac load. The iso-S -petasin-induced decrease in CICR may play a role in its cardiac depressant effect. [source]

    The influence of multi-scale environmental variables on the distribution of terricolous lichens in a fog desert

    Jennifer S. Lalley
    Abstract Question: How do environmental variables in a hyper-arid fog desert influence the distribution patterns of terricolous lichens on both macro- and micro-scales? Location: Namib Desert, Namibia. Methods: Sites with varying lichen species cover were sampled for environmental variables on a macro-scale (elevation, slope degree, aspect, proximity to river channels, and fog deposition) and on a micro-scale (soil structure and chemistry). Macro-scale and micro-scale variables were analysed separately for associations with lichen species cover using constrained ordination (DCCA) and unconstrained ordination (DCA). Explanatory variables that dominated the first two axes of the constrained ordinations were tested against a lichen cover gradient. Results: Elevation and proximity to river channels were the most significant drivers of lichen species cover in the macro-scale DCCA, but results of the DCA suggest that a considerable percentage of variation in lichen species cover is unexplained by these variables. On a micro-scale, sediment particle size explained a majority of lichen community variations, followed by soil pH. When both macro and micro-scale variables were tested along a lichen cover gradient, soil pH was the only variable to show a significant relationship to lichen cover. Conclusion: The findings suggest that landscape variables contribute to variations in lichen species cover, but that stronger links occur between lichen growth and small-scale variations in soil characteristics, supporting the need for multi-scale approaches in the management of threatened biological soil crust communities and related ecosystem functions. [source]