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51.
Nanees F El-Malkey Amira E Alsemeh Wesam MR Ashour Nancy H Hassan Husam M Edrees 《Experimental biology and medicine (Maywood, N.J.)》2021,246(11):1307
Intestinal tissue is highly susceptible to ischemia/reperfusion injury in many hazardous health conditions. The anti-inflammatory and antioxidant glycoprotein fetuin-A showed efficacy in cerebral ischemic injury; however, its protective role against intestinal ischemia/reperfusion remains elusive. Therefore, this study investigated the protective role of fetuin-A supplementation against intestinal structural changes and dysfunction in a rat model of intestinal ischemia/reperfusion. We equally divided 72 male rats into control, sham, ischemia/reperfusion, and fetuin-A-pretreated ischemia/reperfusion (100 mg/kg/day fetuin-A intraperitoneally for three days prior to surgery and a third dose 1 h prior to the experiment) groups. After 2 h of reperfusion, the jejunum was dissected and examined for spontaneous contractility. A jejunal homogenate was used to assess inflammatory and oxidative stress enzymes. Staining of histological sections was carried out with hematoxylin, eosin and Masson’s trichrome stain for evaluation. Immunohistochemistry was performed to detect autophagy proteins beclin-1, LC3, and p62. This study found that fetuin-A significantly improved ischemia/reperfusion-induced mucosal injury by reducing the percentage of areas of collagen deposition, increasing the amplitude of spontaneous contraction, decreasing inflammation and oxidative stress, and upregulating p62 expression, which was accompanied by beclin-1 and LC3 downregulation. Our findings suggest that fetuin-A treatment can prevent ischemia/reperfusion-induced jejunal structural and functional changes by increasing antioxidant activity and regulating autophagy disturbances observed in the ischemia/reperfusion rat model. Furthermore, fetuin-A may provide a protective influence against intestinal ischemia/reperfusion complications. 相似文献
52.
Interannual Invariability of Forest Evapotranspiration and Its Consequence to Water Flow Downstream 总被引:1,自引:0,他引:1
A. Christopher Oishi Ram Oren Kimberly A. Novick Sari Palmroth Gabriel G. Katul 《Ecosystems》2010,13(3):421-436
Although drought in temperate deciduous forests decreases transpiration rates of many species, stand-level transpiration and
total evapotranspiration is often reported to exhibit only minor interannual variability with precipitation. This apparent
contradiction was investigated using four years of transpiration estimates from sap flux, interception–evaporation estimates
from precipitation and throughfall gauges, modeled soil evaporation and drainage estimates, and eddy covariance data in a
mature oak-hickory forest in North Carolina, USA. The study period included one severe drought year and one year of well above-average
precipitation. Normalized for atmospheric conditions, transpiration rates of some species were lower in drought than in wet
periods whereas others did not respond to drought. However, atmospheric conditions during drought periods are unlike conditions
during typical growing season periods. The rainy days that are required to maintain drought-free periods are characterized
by low atmospheric vapor pressure deficit, leading to very low transpiration. In contrast, days with low air vapor pressure
deficit were practically absent during drought and moderate levels of transpiration were maintained throughout despite the
drying soil. Thus, integrated over the growing season, canopy transpiration was not reduced by drought. In addition, high
vapor pressure deficit during drought periods sustained appreciable soil evaporation rates. As a result, despite the large
interannual variation in precipitation (ranging from 934 to 1346 mm), annual evapotranspiration varied little (610–668 mm),
increasing only slightly with precipitation, due to increased canopy rainfall interception. Because forest evapotranspiration
shows only modest changes with annual precipitation, lower precipitation translates to decreased replenishment of groundwater
and outflow, and thus the supply of water to downstream ecosystems and water bodies. 相似文献
53.
Identifying the individuals within a population can generate information on life history parameters, generate input data for conservation models, and highlight behavioural traits that may affect management decisions and error or bias within census methods. Individual animals can be discriminated by features of their vocalisations. This vocal individuality can be utilised as an alternative marking technique in situations where the marks are difficult to detect or animals are sensitive to disturbance. Vocal individuality can also be used in cases were the capture and handling of an animal is either logistically or ethically problematic. Many studies have suggested that vocal individuality can be used to count and monitor populations over time; however, few have explicitly tested the method in this role. In this review we discuss methods for extracting individuality information from vocalisations and techniques for using this to count and monitor populations over time. We present case studies in birds where vocal individuality has been applied to conservation and we discuss its role in mammals. 相似文献
54.
55.
BD Pascal MJ Chalmers SA Busby CC Mader MR Southern NF Tsinoremas PR Griffin 《BMC bioinformatics》2007,8(1):156
Background
The combination of mass spectrometry and solution phase amide hydrogen/deuterium exchange (H/D exchange) experiments is an effective method for characterizing protein dynamics, and protein-protein or protein-ligand interactions. Despite methodological advancements and improvements in instrumentation and automation, data analysis and display remains a tedious process. The factors that contribute to this bottleneck are the large number of data points produced in a typical experiment, each requiring manual curation and validation, and then calculation of the level of backbone amide exchange. Tools have become available that address some of these issues, but lack sufficient integration, functionality, and accessibility required to address the needs of the H/D exchange community. To date there is no software for the analysis of H/D exchange data that comprehensively addresses these issues. 相似文献56.
We investigated the functional and structural responses of Scots pine to climate and estimated the importance of the genotype
on the traits studied. We analysed 13C isotope discrimination (Δ13C) of various provenances in a common garden experiment and gas exchange characteristics for provenances growing in their
natural environment. No clear climatic trend was found in the foliar Δ13C values of common garden trees. Similar results were obtained from estimation of λ (a largely VPD, temperature and light
independent measure of intrinsic water use efficiency) from the gas exchange data. The ratio of needle mass to unit stem area
and branch area to stem area increased towards south in both experiments and hence, seemed to be genetic. Trees from drier
and warmer conditions seemed not to have either lower needle mass or higher intrinsic water use efficiency compared to northern
latitudes.
Received: 6 November 1998 / Accepted: 1 July 1999 相似文献
57.
BACKGROUND: By 2016, the proportion of Canadians older than 65 years of age will increase to 16%, and there will be an increase in the absolute number of cases of cardiovascular disease in older Canadians. The Canadian Heart Health Surveys database provides information about this population upon which health policy related to cardiovascular disease can be based. This paper presents for the first time population-based data on the risk factors for cardiovascular disease in older Canadians. METHODS: Canadians from all 10 provinces participated in surveys of cardiovascular risk factors; health insurance registries were used as sampling frames. In each province, probability samples of 2200 adults 18 to 74 years old not living in institutions, on reserves or in military camps were asked to participate in interviews and to undergo testing at clinics for major risk factors for cardiovascular disease. RESULTS: A total of 2739 men (response rate 70%) and 2617 women (response rate 66%) aged 55 to 74 years participated in the survey and also provided follow-up clinical measurements at the clinic. Overall, 52% of participants were hypertensive, 26% had isolated systolic hypertension, and 30% had a total blood cholesterol level of 6.2 mmol/L or greater. Rates of current smoking were lower in women than men (17% v. 22%). Overall, 87% of men and 78% of women who were current smokers smoked at least 10 cigarettes per day. Only slightly more than half of participants exercised at least once a week for at least 15 minutes, and almost half had a body mass index of 27 or greater. In only 4% was no major risk factor for cardiovascular disease detected. INTERPRETATION: Significant numbers of older Canadians have one or more major risk factors for cardiovascular disease. Many of these risk factors are amenable to modification. 相似文献
58.
Immunohistochemistry (IHC) is used to detect antibody-specific antigens in tissues; the results depend on the ability of the primary antibodies to bind to their antigens. Therefore, results depend on the quality of preservation of the specimen. Many investigators have overcome the deleterious effects of over-fixation on the binding of primary antibodies to specimen antigens using IHC, but if the specimen is under-fixed or fixation is delayed, false negative results could be obtained despite certified laboratory practices. Microtubule-associated protein 2 (MAP2) is an abundant microtubule-associate protein that participates in the outgrowth of neuronal processes and synaptic plasticity; it is localized primarily in cell bodies and dendrites of neurons. MAP2 immunolabeling has been reported to be absent in areas of the entorhinal cortex and hippocampus of Alzheimer’s disease brains that were co-localized with the dense-core type of amyloid plaques. It was hypothesized that the lack of MAP2 immunolabeling in these structures was due to the degradation of the MAP2 antigen by the neuronal proteases that were released as the neurons lysed leading to the formation of these plaques. Because MAP2 is sensitive to proteolysis, we hypothesized that changes in MAP2 immunolabeling may be correlated with the degree of fixation of central nervous system (CNS) tissues. We detected normal MAP2 immunolabeling in fixed rat brain tissues, but MAP2 immunolabeling was decreased or lost in unfixed and delayed-fixed rat brain tissues. By contrast, two ubiquitous CNS-specific markers, myelin basic protein and glial fibrillary acidic protein, were unaffected by the degree of fixation in the same tissues. Our observations suggest that preservation of various CNS-specific antigens differs with the degree of fixation and that the lack of MAP2 immunolabeling in the rat brain may indicate inadequate tissue fixation. We recommend applying MAP2 IHC for all CNS tissues as a pre-screen to assess the quality of the tissue preservation and to avoid potentially false negative IHC results. 相似文献
59.
Drake JE Gallet-Budynek A Hofmockel KS Bernhardt ES Billings SA Jackson RB Johnsen KS Lichter J McCarthy HR McCormack ML Moore DJ Oren R Palmroth S Phillips RP Pippen JS Pritchard SG Treseder KK Schlesinger WH Delucia EH Finzi AC 《Ecology letters》2011,14(4):349-357
The earth's future climate state is highly dependent upon changes in terrestrial C storage in response to rising concentrations of atmospheric CO?. Here we show that consistently enhanced rates of net primary production (NPP) are sustained by a C-cascade through the root-microbe-soil system; increases in the flux of C belowground under elevated CO? stimulated microbial activity, accelerated the rate of soil organic matter decomposition and stimulated tree uptake of N bound to this SOM. This process set into motion a positive feedback maintaining greater C gain under elevated CO? as a result of increases in canopy N content and higher photosynthetic N-use efficiency. The ecosystem-level consequence of the enhanced requirement for N and the exchange of plant C for N belowground is the dominance of C storage in tree biomass but the preclusion of a large C sink in the soil. 相似文献
60.
Freya KR Swinnen Paul J Coucke Anne M De Paepe Sofie Symoens Fransiska Malfait Filomena V Gentile Luca Sangiorgi Patrizia D’Eufemia Mauro Celli Ton JTM Garretsen Cor WRJ Cremers Ingeborg JM Dhooge Els MR De Leenheer 《Orphanet journal of rare diseases》2011,6(1):1-8