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181.
Psoriasis is a chronic, immune-mediated skin disease characterized by production of reactive oxygen species due to the activation of tumor necrosis factor alpha (TNF-??), which is thought to be an important factor in inducing and maintaining psoriatic lesions. As an external factor, ultraviolet B (UVB) radiation stimulates TNF-?? production and secretion by human keratinocytes in vitro and can also reach the upper dermis and suppress endothelial cells in vitro. The selenium level in psoriatic patients has been found to be lower than expected, but studies on its role in the pathogenesis of the disease are scarce. Selenium can influence immune response by changing the expression of cytokines and their receptors or by making immune cells more resistant to oxidative stress. It was reported that selenium supplementation had inhibitory effects on TNF-?? levels in patients with psoriasis, but the details are not completely elucidated. Selenium compounds are also known to prevent the in vitro release of UVB-induced proinflammatory cytokines by inhibition of mRNA in human keratinocytes. In the present review, the protective role of selenium in oxidative stress, lesions, and immune system regulation in patients with psoriasis is summarized.  相似文献   
182.
In this study, the detailed pollen morphological structures of some endemic Turkish species of Centaurea amaena Boiss., C. antalyense H. Duman & A. Duran, C. aphrodisea Boiss., C. hierapolitana Boiss., C. luschaniana Heimerl, C. lycia Boiss., C. tossiensis Freyn. Et Sint., and C. wagenitzii Hub.-Mor. (Asteraceae, section Phaloletis) were studied under light microscopy (LM) and scanning electron microscopy (SEM) for the first time. LM and SEM investigations showed that the pollen grains of eight taxa are more or less spheroidal-subprolate, the amb triangular and tricolporate. The exine sculpture is tectate, microechinate-scabrate in the pollen of Centaurea taxa. Spinules are less dense in Centaurea amaena, C. antalyense, C. hierapolitana, and C. lycia, but they are more dense in C. aphrodisea, C. luschaniana, C. tossiensis, and C. wagenitzii. Spinule dimensions are different from each other. The exine has one layer of columellae beneath the spines. We determined all taxa that have the Helianthoid type. Exine sctructure and sculpture as well as spine density and dimensions in Asteraceae are the most reliable characteristics for discriminating taxa.  相似文献   
183.
Two new taxa of Minuartia L. (Caryophyllaceae) from Turkey, Minuartia aksoyi M. Koç & Hamzao?lu sp. nov. and Minuartia buschiana Schischk. subsp. artvinica M. Koç & Hamzao?lu subsp. nov. are described and illustrated. Their taxonomic positions are discussed and they are compared with allied taxa. The distributions of the new and closely related taxa are given. Seed structures were examined by SEM.  相似文献   
184.
A common dietary contaminant, aflatoxin B1 (AFB1), has been shown to be a potent mutagen and carcinogen in humans and many animal species. Since the eradication of AFB1 contamination in agricultural products has been rare, the use of natural or synthetic free radical scavengers could be a potential chemopreventive strategy. Boron compounds like borax (BX) and boric acid are the major components of industry and their antioxidant role has recently been reported. In the present report, we evaluated the capability of BX to inhibit the rate of micronucleus (MN) and sister chromatid exchange (SCE) formations induced by AFB1. There were significant increases (P < 0.05) in both SCE and MN frequencies of cultures treated with AFB1 (3.12 ppm) as compared to controls. However, co-application of BX (1, 2 and 5 ppm) and AFB1 resulted in decreases of SCE and MN rates as compared to the group treated with AFB1 alone. Borax gave 30–50 % protection against AFB1 induced SCEs and MNs. In conclusion, the support of borax was especially useful in aflatoxin-toxicated blood tissue. Thus, the risk on target tissues of AFB1 could be reduced and ensured early recovery from its toxicity.  相似文献   
185.
From the roots of Aconitum vulparia Rchb., collected in Prüm (Germany), a new norditerpenoid alkaloid, named alexhumboldtine, has been isolated along with the known norditerpenoid alkaloids lappaconitine, anthranoyllycoctonine, lycoctonine, puberaconitine, ajacine, and septentriodine. The structure of alexhumboldtine was established on the basis of 1H, 13C, DEPT, homonuclear 1H COSY, NOESY, HSQC, and HMBC NMR studies. From the aerial parts of the plant another norditerpenoid alkaloid, aconorine, has been isolated.  相似文献   
186.
Mating decisions usually involve conflict of interests between sexes. Accordingly, males benefit from increased number of matings, whereas costs of mating favour a lower mating rate for females. The resulting sexual conflict underlies the coevolution of male traits that affect male mating success ('persistence') and female traits that affect female mating patterns ('resistance'). Theoretical studies on the coevolutionary dynamics of male persistence and female resistance assumed that costs of mating and, consequently, the optimal female mating rate are evolutionarily constant. Costs of mating, however, are often caused by male 'persistence' traits that determine mating success. Here, we present a model where the magnitude of costs of mating depend on, and evolve with, male persistence. We find that allowing costs of mating to depend on male persistence results in qualitatively different coevolutionary dynamics. Specifically, we find that male traits such as penis spikes that harm females are not predicted to exhibit runaway selection with female resistance, in contrast to previous theory that predicts indefinite escalation. We argue that it is essential to determine when and to what extent costs of mating are caused by male persistence in order to understand and accurately predict coevolutionary dynamics of traits involved in mating decisions.  相似文献   
187.
Carbonic anhydrases (CA) catalyze activated ester hydrolysis in addition to the hydration of CO(2) to bicarbonate. They also show phosphatase activity with 4-nitrophenyl phosphate as substrate but not sulfatase with the corresponding sulfate. Here we prove that the enzyme is catalyzing the synthesis of cyclic diols from sulfate esters. 5-, 6- and 8-membered ring cyclic sulfates incorporating a neighboring secondary alcohol moiety were treated with CA II and yielded the corresponding cyclic diols. Inhibitory properties of obtained cyclic and original sulfate esters were then investigated on human carbonic anhydrase I (hCA I), hCA II, hCA IV and hCA VI (h?=?human isoform). K(I)-s of these compounds ranged between 32.7-423 μM against hCA I, 2.13-32.4 μM against hCA II, 13.7-234 μM against hCA IV and 76-278 μM against CA VI, respectively. The sulfatase activity of CA with such esters is amazing considering the fact that 4-nitrophenyl-sulfate is not a substrate of these enzymes.  相似文献   
188.
Vascular endothelial growth factor (VEGF) is the important angiogenic factor associated with tumor growth and metastasis in a wide variety of solid tumors. The aim of this study is to investigate the tumor suppressive effect of chitosan/small interfering RNA (siRNA)-VEGF nanoplexes in the rat breast cancer model. Chitosan/siRNA nanoplexes (siVEGF-A, siVEGFR-1, siVEGFR-2) and NRP-1 were prepared in a 15 to1 ratio and injected (intratumorally) into the breast-tumor-bearing Sprague-Dawley rats. Tumor volumes were measured during 21 days. To investigate the effect of chitosan/siRNA nanoplexes on VEGF expression in tumors, VEGF was analyzed with immunohistochemistry and western blotting. The mRNA levels of VEGF in tumor samples were determined with real-time PCR (RT-PCR). After siRNA treatment, a marked reduction in tumor volumes was measured in complex-injected rats (97%). Free siRNA injection showed lower tumor inhibition. Reduction of VEGF protein was also shown with western blotting and immunohistochemistry. Similar results were obtained with RT-PCR also. These results indicate that the chitosan/siRNA targeting to VEGF nanoplexes have a remarkably suppressive effect on VEGF expression and tumor volume in breast cancer model of rats.  相似文献   
189.
Therapeutic effect of interferon-β (IFN-β) treatment has been associated with modulation of the balance between Th1, Th17, Th2 and regulatory T (Treg) cells, whereas the impact of disease modifying drugs on Th9-immunity in multiple sclerosis (MS) has not been studied. To investigate the short-term effects of IFN-β treatment on cytokines in MS, we determined serum levels of IL-17, IL-23, IL-10, IL-4, IFN-γ, IL-9 and TGF-β in relapsing remitting MS patients before and 2 months after IFN-β treatment by ELISA. MS patients showed increased IL-17, IL-23 and IL-4 levels and decreased IL-9 levels as compared to healthy controls. IFN-β treatment only reduced IL-17 and IL-23 levels, whereas the levels of other cytokines remained unchanged. IFN-β treatment appears to exert its earliest therapeutic effect on Th17-immunity. The influence of IL-9 on MS pathogenesis needs to be further studied.  相似文献   
190.
The objective of the study was to determine the effects of repeated bouts of supramaximal exercise on plasma adiponectin, interleukin (IL)-6 and tumor necrosis factor (TNF)-α levels in sedentary men. Fourteen healthy, nonsmoking, and sedentary men aged between 18.4 and 21.4 years participated in the study. All the subjects performed 5 Wingate tests (WTs) with 75 g per kilogram body weight load with 2-minute intervals between the tests. Blood samples were collected at preexercise, immediately after, 15 and 60 minutes after the fifth WT. Serum and plasma samples were stored at -80°C until the time of analysis for myoglobin, adiponectin, IL-6, and TNF-α. Plasma adiponectin levels decreased, whereas IL-6 levels increased postexercise compared with that preexercise. The TNF-α levels were not changed with supramaximal exercise. In conclusion, repeated bouts of supramaximal exercise cause an inflammatory response in exercised muscle and increase in plasma IL-6 levels and decrease in adiponectin concentrations.  相似文献   
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