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1.
Kocaçalişkan I Talan I Terzi I 《Zeitschrift für Naturforschung. C, Journal of biosciences》2006,61(9-10):639-642
Catechol and pyrogallol are allelochemicals which belong to phenolic compounds synthesized in plants. Their antimicrobial activities were investigated on three bacteria (Pseudomonas putida, Pseudomonas pyocyanea, Corynebacterium xerosis) and two fungi (Fusarium oxysporum, Penicillium italicum) phytopathogenic species as test organisms using the disc diffusion method. Both catechol and pyrogallol were found to have antibacterial effects on all the bacteria used in the study at 5 and 10 mM concentrations. Catechol has also been found to have an antifungal effect on the fungi used in the study, whereas no antifungal effects of pyrogallol were observed. The most sensitive species among the bacteria was P. putida which was inhibited by the allelochemicals even at 1 mM concentration. 相似文献
2.
Background
To test a hypothesis that in negative clinical trials of erythropoietin in patients with acute myocardial infarction (MI) the erythropoietin (rhEPO) could be administered outside narrow therapeutic window. Despite overwhelming evidence of cardioprotective properties of rhEPO in animal studies, the outcomes of recently concluded phase II clinical trials have failed to demonstrate the efficacy of rhEPO in patients with acute MI. However, the time between symptoms onset and rhEPO administration in negative clinical trials was much longer that in successful animal experiments.Methodology/Principal Findings
MI was induced in rats either by a permanent ligation of a descending coronary artery or by a 2-hr occlusion followed by a reperfusion. rhEPO, 3000 IU/kg, was administered intraperitoneally at the time of reperfusion, 4 hrs after beginning of reperfusion, or 6 hrs after permanent occlusion. MI size was measured histologically 24 hrs after coronary occlusion. The area of myocardium at risk was similar among groups. The MI size in untreated rats averaged ∼42% of area at risk, or ∼24% of left ventricle, and was reduced by more than 50% (p<0.001) in rats treated with rhEPO at the time of reperfusion. The MI size was not affected by treatment administered 4 hrs after reperfusion or 6 hrs after permanent coronary occlusion. Therefore, our study in a rat experimental model of MI demonstrates that rhEPO administered within 2 hrs of a coronary occlusion effectively reduces MI size, but when rhEPO was administered following a delay similar to that encountered in clinical trials, it had no effect on MI size.Conclusions/Significance
The clinical trials that failed to demonstrate rhEPO efficacy in patients with MI may have missed a narrow therapeutic window defined in animal experiments. 相似文献3.
Ashrafian H Czibik G Bellahcene M Aksentijević D Smith AC Mitchell SJ Dodd MS Kirwan J Byrne JJ Ludwig C Isackson H Yavari A Støttrup NB Contractor H Cahill TJ Sahgal N Ball DR Birkler RI Hargreaves I Tennant DA Land J Lygate CA Johannsen M Kharbanda RK Neubauer S Redwood C de Cabo R Ahmet I Talan M Günther UL Robinson AJ Viant MR Pollard PJ Tyler DJ Watkins H 《Cell metabolism》2012,15(3):361-371
4.
Ismayil Ahmet Edward Spangler Barbara Shukitt-Hale Magdalena Juhaszova Steven J. Sollott James A. Joseph Donald K. Ingram Mark Talan 《PloS one》2009,4(6)
Objectives
to assess the cardioprotective properties of a blueberry enriched diet (BD).Background
Reactive oxygen species (ROS) play a major role in ischemia-related myocardial injury. The attempts to use synthetic antioxidants to block the detrimental effects of ROS have produced mixed or negative results precipitating the interest in natural products. Blueberries are readily available product with the highest antioxidant capacity among fruits and vegetables.Methods and Results
Following 3-mo of BD or a regular control diet (CD), the threshold for mitochondrial permeability transition (tMPT) was measured in isolated cardiomyocytes obtained from young male Fischer-344 rats. Compared to CD, BD resulted in a 24% increase (p<0.001) of ROS indexed tMPT. The remaining animals were subjected to a permanent ligation of the left descending coronary artery. 24 hrs later resulting myocardial infarction (MI) in rats on BD was 22% less than in CD rats (p<0.01). Significantly less TUNEL(+) cardiomyocytes (2% vs 9%) and 40% less inflammation cells were observed in the myocardial area at risk of BD compared to CD rats (p<0.01). In the subgroup of rats, after coronary ligation the original diet was either continued or switched to the opposite one, and cardiac remodeling and MI expansion were followed by serial echocardiography for 10 weeks. Measurements suggested that continuation of BD or its withdrawal after MI attenuated or accelerated rates of post MI cardiac remodeling and MI expansion.Conclusion
A blueberry-enriched diet protected the myocardium from induced ischemic damage and demonstrated the potential to attenuate the development of post MI chronic heart failure. 相似文献5.
Central neural correlates of learned heart rate control during exercise: central command demystified
Chefer Svetlana I.; Talan Mark I.; Engel Bernard T. 《Journal of applied physiology》1997,83(5):1448-1453
Chefer, Svetlana I., Mark I. Talan, and Bernard T. Engel.Central neural correlates of learned heart rate control during exercise: central command demystified. J. Appl.Physiol. 83(5): 1448-1453, 1997.To identify thebrain areas involved in central command, four monkeys were trained toattenuate the tachycardia of exercise while different brain sitesaffecting heart rate (HR) were simultaneously stimulated electrically.Among 24 brain sites located mostly in the limbic structures, we haveidentified four types of control systems that mediate cardiovascularand motor behavior during exercise. One system increases HRequivalently during both exercise and operantly controlled HR, whereasanother increases HR during both tasks and abolishes operant HRcontrol. In the third system, the effect of brain stimulation on HR is attenuated during exercise and during exercise with operantly controlled HR. The fourth system increases HR in both tasks, but itseffect is significantly attenuated during operant HR control. Webelieve that this last system, which includes the mediodorsal nucleus,nucleus ventralis anterior, and cingulate cortex, plays a significantrole in central command. 相似文献
6.
Ahmet I Tae HJ Juhaszova M Riordon DR Boheler KR Sollott SJ Brines M Cerami A Lakatta EG Talan MI 《Molecular medicine (Cambridge, Mass.)》2011,17(3-4):194-200
Strong cardioprotective properties of erythropoietin (EPO) reported over the last 10 years have been difficult to translate to clinical applications for ischemic cardioprotection owing to undesirable parallel activation of erythropoiesis and thrombogenesis. A pyroglutamate helix B surface peptide (pHBP), recently engineered to include only a part of the EPO molecule that does not bind to EPO receptor and thus, is not erythropoietic, retains tissue protective properties of EPO. Here we compared the ability of pHBP and EPO to protect cardiac myocytes from oxidative stress in vitro and cardiac tissue from ischemic damage in vivo. HBP, similar to EPO, increased the reactive oxygen species (ROS) threshold for induction of the mitochondrial permeability transition by 40%. In an experimental model of myocardial infarction induced by permanent ligation of a coronary artery in rats, a single bolus injection of 60 μg/kg of pHBP immediately after coronary ligation, similar to EPO, reduced apoptosis in the myocardial area at risk, examined 24 h later, by 80% and inflammation by 34%. Myocardial infarction (MI) measured 24 h after coronary ligation was similarly reduced by 50% in both pHBP- and EPO-treated rats. Two wks after surgery, left ventricular remodeling (ventricular dilation) and functional decline (fall in ejection fraction) assessed by echocardiography were significantly and similarly attenuated in pHBP- and EPO-treated rats, and MI size was reduced by 25%. The effect was retained during the 6-wk follow-up. A single bolus injection of pHBP immediately after coronary ligation was effective in reduction of MI size in a dose as low as 1 μg/kg, but was ineffective at a 60 μg/kg dose if administered 24 h after MI induction. We conclude that pHBP is equally cardioprotective with EPO and deserves further consideration as a safer alternative to rhEPO in the search for therapeutic options to reduce myocardial damage following blockade of the coronary circulation. 相似文献
7.
The pro-angiogenic cytokine pleiotrophin potentiates cardiomyocyte apoptosis through inhibition of endogenous AKT/PKB activity 总被引:1,自引:0,他引:1
Li J Wei H Chesley A Moon C Krawczyk M Volkova M Ziman B Margulies KB Talan M Crow MT Boheler KR 《The Journal of biological chemistry》2007,282(48):34984-34993
Pleiotrophin is a development-regulated cytokine and growth factor that can promote angiogenesis, cell proliferation, or differentiation, and it has been reported to have neovasculogenic effects in damaged heart. Developmentally, it is prominently expressed in fetal and neonatal hearts, but it is minimally expressed in normal adult heart. Conversely, we show in a rat model of myocardial infarction and in human dilated cardiomyopathy that pleiotrophin is markedly up-regulated. To elucidate the effects of pleiotrophin on cardiac contractile cells, we employed primary cultures of rat neonatal and adult cardiomyocytes. We show that pleiotrophin is released from cardiomyocytes in vitro in response to hypoxia and that the addition of recombinant pleiotrophin promotes caspase-mediated genomic DNA fragmentation in a dose- and time-dependent manner. Functionally, it potentiates the apoptotic response of neonatal cardiomyocytes to hypoxic stress and to ultraviolet irradiation and of adult cardiomyocytes to hypoxia-reoxygenation. Moreover, UV-induced apoptosis in neonatal cardiomyocytes can be partially inhibited by small interfering RNA-mediated knockdown of endogenous pleiotrophin. Mechanistically, pleiotrophin antagonizes IGF-1 associated Ser-473 phosphorylation of AKT/PKB, and it concomitantly decreases both BAD and GSK3beta phosphorylation. Adenoviral expression of constitutively active AKT and lithium chloride-mediated inhibition of GSK3beta reduce the potentiated programmed cell death elicited by pleiotrophin. These latter data indicate that pleiotrophin potentiates cardiomyocyte cell death, at least partially, through inhibition of AKT signaling. In conclusion, we have uncovered a novel function for pleiotrophin on heart cells following injury. It fosters cardiomyocyte programmed cell death in response to pro-apoptotic stress, which may be critical to myocardial injury repair. 相似文献
8.
Cytogenetic characteristics of the radiation-induced chromosomal instability and its persistence in human peripheral blood lymphocytes due to the bystander effect from exposure to ionizing radiation in vitro and in vivo at low and high doses has been established using a coculturing of irradiated and nonirradiated human peripheral blood lymphocytes from persons of different sexes and G-banding metaphase chromosomes staining. 相似文献
9.
Ruiqian Wan Ismayil Ahmet Martin Brown Aiwu Cheng Naomi Kamimura Mark Talan Mark P. Mattson 《The Journal of nutritional biochemistry》2010,21(5):413-417
It has been reported that dietary energy restriction, including intermittent fasting (IF), can protect heart and brain cells against injury and improve functional outcome in animal models of myocardial infarction (MI) and stroke. Here we report that IF improves glycemic control and protects the myocardium against ischemia-induced cell damage and inflammation in rats. Echocardiographic analysis of heart structural and functional variables revealed that IF attenuates the growth-related increase in posterior ventricular wall thickness, end systolic and diastolic volumes, and reduces the ejection fraction. The size of the ischemic infarct 24 h following permanent ligation of a coronary artery was significantly smaller, and markers of inflammation (infiltration of leukocytes in the area at risk and plasma IL-6 levels) were less, in IF rats compared to rats on the control diet. IF resulted in increased levels of circulating adiponectin prior to and after MI. Because recent studies have shown that adiponectin can protect the heart against ischemic injury, our findings suggest a potential role for adiponectin as a mediator of the cardioprotective effect of IF. 相似文献
10.
Ahn D Cheng L Moon C Spurgeon H Lakatta EG Talan MI 《American journal of physiology. Heart and circulatory physiology》2004,286(3):H1201-H1207
The ability to create experimental myocardial infarctions of reproducible size and location is tantamount to progress in multiple facets of ischemic heart disease research. Branches of the mouse left main descending coronary artery penetrate the myocardium close to their origin and require "blind" ligation. Our objective was to develop a technique for ligation of nonvisible coronary artery branches to permit the reliable creation of infarcts of uniformly small size and location. From latex castings of the left coronary artery of C57BL/6J mice (n = 53), we calculated the highest probability for the location of branch points of two of three left ventricular (LV) branches distal to the origin of the left main descending artery. On the basis of these anatomic probabilities, we blindly ligated two areas that were likely to be locations of these nonvisible LV branches. We were successful in producing two types of small transmural myocardial infarctions (16.04 +/- 3.64 and 4.68 +/- 1.47% of the LV) in 57% of attempts. Thus our branch pattern probability-assisted method permits routine creation of small infarcts of uniform size in the mouse. 相似文献