927 resultados para Physiological indexes
Resumo:
PURPOSE OF REVIEW Neutrophil extravasation from the blood into tissues is initiated by tethering and rolling of neutrophils on endothelial cells, followed by neutrophil integrin activation and shear resistant arrest, crawling, diapedesis and breaching the endothelial basement membrane harbouring pericytes. Endothelial intercellular cell adhesion molecule (ICAM)-1 and ICAM-2, in conjunction with ICAM-1 on pericytes, critically contribute to each step. In addition, epithelial ICAM-1 is involved in neutrophil migration to peri-epithelial sites. The most recent findings on the role of ICAM-1 and ICAM-2 for neutrophil migration into tissues will be reviewed here. RECENT FINDINGS Signalling via endothelial ICAM-1 and ICAM-2 contributes to stiffness of the endothelial cells at sites of chronic inflammation and junctional maturation, respectively. Endothelial ICAM-2 contributes to neutrophil crawling and initiation of paracellular diapedesis, which then proceeds independent of ICAM-2. Substantial transcellular neutrophil diapedesis across the blood-brain barrier is strictly dependent on endothelial ICAM-1 and ICAM-2. Endothelial ICAM-1 or ICAM-2 is involved in neutrophil-mediated plasma leakage. ICAM-1 on pericytes assists the final step of neutrophil extravasation. Epithelial ICAM-1 rather indirectly promotes neutrophil migration to peri-epithelial sites. SUMMARY ICAM-1 and ICAM-2 are involved in each step of neutrophil extravasation, and have redundant but also distinct functions. Analysis of the role of endothelial ICAM-1 requires simultaneous consideration of ICAM-2.
Resumo:
The relationships among animal form, function and performance are complex, and vary across environments. Therefore, it can be difficult to identify morphological and/or physiological traits responsible for enhancing performance in a given habitat. In fishes, differences in swimming performance across water flow gradients are related to morphological variation among and within species. However, physiological traits related to performance have been less well studied. We experimentally reared juvenile damselfish, Acanthochromis polyacanthus, under different water flow regimes to test 1) whether aspects of swimming physiology and morphology show plastic responses to water flow, 2) whether trait divergence correlates with swimming performance and 3) whether flow environment relates to performance differences observed in wild fish. We found that maximum metabolic rate, aerobic scope and blood haematocrit were higher in wave-reared fish compared to fish reared in low water flow. However, pectoral fin shape, which tends to correlate with sustained swimming performance, did not differ between rearing treatments or collection sites. Maximum metabolic rate was the best overall predictor of individual swimming performance; fin shape and fish total length were 3.3 and 3.7 times less likely than maximum metabolic rate to explain differences in critical swimming speed. Performance differences induced in fish reared in different flow environments were less pronounced than in wild fish but similar in direction. Our results suggest that exposure to water motion induces plastic physiological changes which enhance swimming performance in A. polyacanthus. Thus, functional relationships between fish morphology and performance across flow habitats should also consider differences in physiology.
Resumo:
Alien plants provide a unique opportunity to study evolution in novel environments, but relatively little is known about the extent to which they become locally adapted to different environments across their new range. Here, we compare northern and southern populations of the introduced species Senecio squalidus in Britain; S. squalidus has been in southern Britain for approximately 200 years and reached Scotland only about 50 years ago. We conducted common garden experiments at sites in the north and south of the species’ range in Britain. We also conducted glasshouse and growth chamber experiments to test the hypothesis that southern genotypes flower later, are more drought-tolerant, germinate and establish better at warmer temperatures, and are less sensitive to cold stress than their more northern counterparts. Results from the common garden experiments are largely consistent with the hypothesis of rapid adaptive divergence of populations of the species within the introduced range, with genotypes typically showing a home-site advantage. Results from the glasshouse and growth chamber experiments demonstrate adaptive divergence in ability to tolerate drought stress and high temperatures, as well as in phenology. In particular, southern genotypes were more tolerant of dry conditions and high temperatures and they flowered later than northern genotypes. Our results show that rapid local adaptation can occur in alien species, and they have implications for our understanding of the ecological genetics of range expansion of introduced weeds.
Resumo:
BACKGROUND Panic disorder is characterised by the presence of recurrent unexpected panic attacks, discrete periods of fear or anxiety that have a rapid onset and include symptoms such as racing heart, chest pain, sweating and shaking. Panic disorder is common in the general population, with a lifetime prevalence of 1% to 4%. A previous Cochrane meta-analysis suggested that psychological therapy (either alone or combined with pharmacotherapy) can be chosen as a first-line treatment for panic disorder with or without agoraphobia. However, it is not yet clear whether certain psychological therapies can be considered superior to others. In order to answer this question, in this review we performed a network meta-analysis (NMA), in which we compared eight different forms of psychological therapy and three forms of a control condition. OBJECTIVES To assess the comparative efficacy and acceptability of different psychological therapies and different control conditions for panic disorder, with or without agoraphobia, in adults. SEARCH METHODS We conducted the main searches in the CCDANCTR electronic databases (studies and references registers), all years to 16 March 2015. We conducted complementary searches in PubMed and trials registries. Supplementary searches included reference lists of included studies, citation indexes, personal communication to the authors of all included studies and grey literature searches in OpenSIGLE. We applied no restrictions on date, language or publication status. SELECTION CRITERIA We included all relevant randomised controlled trials (RCTs) focusing on adults with a formal diagnosis of panic disorder with or without agoraphobia. We considered the following psychological therapies: psychoeducation (PE), supportive psychotherapy (SP), physiological therapies (PT), behaviour therapy (BT), cognitive therapy (CT), cognitive behaviour therapy (CBT), third-wave CBT (3W) and psychodynamic therapies (PD). We included both individual and group formats. Therapies had to be administered face-to-face. The comparator interventions considered for this review were: no treatment (NT), wait list (WL) and attention/psychological placebo (APP). For this review we considered four short-term (ST) outcomes (ST-remission, ST-response, ST-dropouts, ST-improvement on a continuous scale) and one long-term (LT) outcome (LT-remission/response). DATA COLLECTION AND ANALYSIS As a first step, we conducted a systematic search of all relevant papers according to the inclusion criteria. For each outcome, we then constructed a treatment network in order to clarify the extent to which each type of therapy and each comparison had been investigated in the available literature. Then, for each available comparison, we conducted a random-effects meta-analysis. Subsequently, we performed a network meta-analysis in order to synthesise the available direct evidence with indirect evidence, and to obtain an overall effect size estimate for each possible pair of therapies in the network. Finally, we calculated a probabilistic ranking of the different psychological therapies and control conditions for each outcome. MAIN RESULTS We identified 1432 references; after screening, we included 60 studies in the final qualitative analyses. Among these, 54 (including 3021 patients) were also included in the quantitative analyses. With respect to the analyses for the first of our primary outcomes, (short-term remission), the most studied of the included psychological therapies was CBT (32 studies), followed by BT (12 studies), PT (10 studies), CT (three studies), SP (three studies) and PD (two studies).The quality of the evidence for the entire network was found to be low for all outcomes. The quality of the evidence for CBT vs NT, CBT vs SP and CBT vs PD was low to very low, depending on the outcome. The majority of the included studies were at unclear risk of bias with regard to the randomisation process. We found almost half of the included studies to be at high risk of attrition bias and detection bias. We also found selective outcome reporting bias to be present and we strongly suspected publication bias. Finally, we found almost half of the included studies to be at high risk of researcher allegiance bias.Overall the networks appeared to be well connected, but were generally underpowered to detect any important disagreement between direct and indirect evidence. The results showed the superiority of psychological therapies over the WL condition, although this finding was amplified by evident small study effects (SSE). The NMAs for ST-remission, ST-response and ST-improvement on a continuous scale showed well-replicated evidence in favour of CBT, as well as some sparse but relevant evidence in favour of PD and SP, over other therapies. In terms of ST-dropouts, PD and 3W showed better tolerability over other psychological therapies in the short term. In the long term, CBT and PD showed the highest level of remission/response, suggesting that the effects of these two treatments may be more stable with respect to other psychological therapies. However, all the mentioned differences among active treatments must be interpreted while taking into account that in most cases the effect sizes were small and/or results were imprecise. AUTHORS' CONCLUSIONS There is no high-quality, unequivocal evidence to support one psychological therapy over the others for the treatment of panic disorder with or without agoraphobia in adults. However, the results show that CBT - the most extensively studied among the included psychological therapies - was often superior to other therapies, although the effect size was small and the level of precision was often insufficient or clinically irrelevant. In the only two studies available that explored PD, this treatment showed promising results, although further research is needed in order to better explore the relative efficacy of PD with respect to CBT. Furthermore, PD appeared to be the best tolerated (in terms of ST-dropouts) among psychological treatments. Unexpectedly, we found some evidence in support of the possible viability of non-specific supportive psychotherapy for the treatment of panic disorder; however, the results concerning SP should be interpreted cautiously because of the sparsity of evidence regarding this treatment and, as in the case of PD, further research is needed to explore this issue. Behaviour therapy did not appear to be a valid alternative to CBT as a first-line treatment for patients with panic disorder with or without agoraphobia.
Resumo:
In equatorial regions, where tree rings are less distinct or even absent, the response of forests to high-frequency climate variability is poorly understood. We measured stable carbon and oxygen isotopes in anatomically distinct, annual growth rings of four Pericopsis elata trees from a plantation in the Congo Basin, to assess their sensitivity to recorded changes in precipitation over the last 50 y. Our results suggest that oxygen isotopes have high common signal strength (EPS = 0.74), and respond to multi-annual precipitation variability at the regional scale, with low δ18O values (28–29‰) during wetter conditions (1960–1970). Conversely, δ13C are mostly related to growth variation, which in a light-demanding species are driven by competition for light. Differences in δ13C values between fast- and slow-growing trees (c. 2‰), result in low common signal strength (EPS = 0.37) and are driven by micro-site conditions rather than by climate. This study highlights the potential for understanding the causes of growth variation in P. elata as well as past hydroclimatic changes, in a climatically complex region characterized by a bimodal distribution in precipitation.
Resumo:
Glycogen is a major substrate in energy metabolism and particularly important to prevent hypoglycemia in pathologies of glucose homeostasis such as type 1 diabetes mellitus (T1DM). (13) C-MRS is increasingly used to determine glycogen in skeletal muscle and liver non-invasively; however, the low signal-to-noise ratio leads to long acquisition times, particularly when glycogen levels are determined before and after interventions. In order to ease the requirements for the subjects and to avoid systematic effects of the lengthy examination, we evaluated if a standardized preparation period would allow us to shift the baseline (pre-intervention) experiments to a preceding day. Based on natural abundance (13) C-MRS on a clinical 3 T MR system the present study investigated the test-retest reliability of glycogen measurements in patients with T1DM and matched controls (n = 10 each group) in quadriceps muscle and liver. Prior to the MR examination, participants followed a standardized diet and avoided strenuous exercise for two days. The average coefficient of variation (CV) of myocellular glycogen levels was 9.7% in patients with T1DM compared with 6.6% in controls after a 2 week period, while hepatic glycogen variability was 13.3% in patients with T1DM and 14.6% in controls. For comparison, a single-session test-retest variability in four healthy volunteers resulted in 9.5% for skeletal muscle and 14.3% for liver. Glycogen levels in muscle and liver were not statistically different between test and retest, except for hepatic glycogen, which decreased in T1DM patients in the retest examination, but without an increase of the group distribution. Since the CVs of glycogen levels determined in a "single session" versus "within weeks" are comparable, we conclude that the major source of uncertainty is the methodological error and that physiological variations can be minimized by a pre-study standardization. For hepatic glycogen examinations, familiarization sessions (MR and potentially strenuous interventions) are recommended. Copyright © 2016 John Wiley & Sons, Ltd.
Resumo:
Morphological variation within and among many species of algae show correlated life history traits. The trade-offs of Life history traits among different morphs are presumed to be determined by morphology. Form-function hypotheses also predict that algae of different morphological groups exhibit different tolerances to physiological stress, whereas algae within a morphological group respond similarly to stress. We tested this hypothesis by comparing photosynthetic and respiratory responses to variation in season, light, temperature, desiccation and freezing among the morphologically similar fronds of Chondrus crispus and Mastocarpus stellatus and the alternate stage crust of M. stellatus. Physiological differences between fronds of the 2 species and crusts and fronds were consistent with their patterns of distribution and abundance in the intertidal zone. However, there was no clear relationship between algal morphology and physiological response to environmental variation. These results suggest that among macroalgae the correlation between Life history traits and morphology is not always causal. Rather, the link between life history traits and morphology is constrained by the extent to which physiological characteristics codetermine these features.
Resumo:
We develop coincident and leading employment indexes for the Connecticut economy. Four employment-related variables enter the coincident index while five employment-related variables enter the leading index. The peaks and troughs in the leading index lead the peaks and troughs in the coincident index by an average of 3 and 9 months. Finally, we use the leading index in vector-autoregressive (VAR) and Bayesian vector-autoregressive (BVAR) models to forecast the coincident index, nonfarm employment, and the unemployment rate.
Resumo:
J. Leveen
Resumo:
Cytochromes P450 4Fs (CYP4F) are a subfamily of enzymes involved in arachidonic acid metabolism with highest catalytic activity towards leukotriene B 4 (LTB4), a potent chemoattractant involved in prompting inflammation. CYP4F-mediated metabolism of LTB4 leads to inactive ω-hydroxy products incapable of initiating chemotaxis and the inflammatory stimuli that result in the influx of inflammatory cells. Our hypothesis is based on the catalytic ability of CYP4Fs to inactivate pro-inflammatory LTB4 which assures these enzymes a pivotal role in the process of inflammation resolution. ^ To test this hypothesis and evaluate the changes in CYP4F expression under complex inflammatory conditions, we designed two mouse models, one challenged with lipopolysaccharide (LPS) as a sterile model of sepsis and the other challenged with a systemic live bacterial infection of Citrobacter rodentium, an equivalent of the human enterobacterium E. coli pathogen invasion. Based on the evidence that Peroxisome Proliferator Activated Receptors (PPARs) play an active role in inflammation regulation, we also examined PPARs as a regulation mechanism in CYP4F expression during inflammation using PPARα knockout mice under LPS challenge. Using the Citrobacter rodentium model of inflammation, we studied CYP4F levels to compare them to those in LPS challenged animals. LPS-triggered inflammation signal is mediated by Toll-like 4 (TLR4) receptors which specifically respond to LPS in association with several other proteins. Using TLR4 knockout mice challenged with Citrobacter rodentium we addressed possible mediation of CYP4F expression regulation via these receptors. ^ Our results show isoform- and tissue-specific CYP4F expression in all the tissues examined. The Citrobacter rodentium inflammation model revealed significant reduction in liver expression of CYP4F14 and CYP4F15 and an up-regulation of gene expression of CYP4F16 and CYP4F18. TLR4 knockout studies showed that the decrease in hepatic CYP4F15 expression is TLR4-dependent. CYP4F expression in kidney shows down-regulation of CYP4F14 and CYP4F15 and up-regulation of CYP4F18 expression. In the LPS inflammation model, we showed similar patterns of CYP4F changes as in Citrobacter rodentium -infected mice. The renal profile of CYP4Fs in PPARα knockout mice with LPS challenge showed CYP4F15 down-regulation to be PPARα dependent. Our study confirmed tissue- and isoform-specific regulation of CYP4F isoforms in the course of inflammation. ^
Resumo:
This study focused on the possible relationship between certain physiological and psychological variables and the cessation of smoking. The population studied was employees enrolled in a multimodality smoking cessation program at the local offices of a major American corporation. In order to be eligible to participate, each individual must have become a non-smoker by the end of the smoking cessation program.^ Three physiological measures were taken on each individual while performing a relaxation exercise; (1) Electromyogram (EMG), (2) Galvanic Skin Response (GSR), and (3) Skin Temperature. The psychological measure consisted of the variable "anxiety" in the Cattell 16-PF personality inventory. Individual's self report of their smoking status was verified through a test for expired carbon monoxide levels.^ For the total population (N-31) no significant relationships were found between the physiological and psychological variable measured and cessation; however, with the removal of two cases discovered during the post-test interview to be influenced by external factors of high caffeine level and a severe family crisis, the measure of EMG, attained significance in discriminating between the successful and unsuccessful in Smoking Cessation. ^
Resumo:
The occurrence of group G streptococci in cats and evaluation of the recovered organisms as potential human pathogens was investigated. Throat swabs were obtained from 89 cats (47 males and 42 females) and vaginal swabs from 39 female cats. Eighty-three of the examined cats were housed in individual cages at a University Animal Care Facility. Six cats, 2 mature males, 2 mature females and 2 young females were family pets in a rural area. Beta-hemolytic streptococci were recovered from 33 (37%) of the 89 cat throats cultured, and 27 (30.3%) were identified as group G. More males (34%) than females (24%) had throat cultures positive for group G. From the 39 vaginal cultures examined, 24 (61.5%) contained beta-hemolytic streptococci and 23 (58.9%) were identified as group G streptococci. Streptococci were not recovered from the vaginal cultures of the 5 females under 6 months of age.^ Thirty one group G streptococci isolated from cats were compared with 37 isolates of group G obtained from humans (health status or site of origin unknown). More group G cat isolates (81%) produced deoxyribonuclease (DNase) than did the human isolates (36%). The proportion of cat throat and vaginal isolates producing DNase was the same. Production of nicotinamide adenine dinucleotide glycohydrolase (NADase) by group G isolates of human origin was 70%, cat throat isolates 53% and cat vaginal isolates 37%. The Serum Opacity Factor was present in 73% of the cat throat isolates of group G, 43.7% of the cat vaginal isolates and 58.6% of the human isolates. Possession of an anti-phagocytic factor (M protein like substance) demonstrated by the ability to multiply in fresh human blood was greater in the group G from cat throats (46.7%) than from cat vagina (37.5%) or from the human isolates (13.5%). Many of the biochemical characteristics of the group G streptococci of cat origin were more similar to the biochemical characteristics of group A streptococci, than to the characteristics of group G of human origin. The group G streptococci, found in a large number of cats, could be potential human pathogens, as their physiological and biological characteristics are very similar to those of group A, a known human pathogen. ^