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The prevention of histamine-induced gastric and duodenal ulceration in the guinea-pig has been examined using a series of undegraded and degraded carrageenans. Undegraded carrageenans were active at lower doses than degraded carrageenans. The high viscosity of the undegraded carrageenans in solution prevented their use in larger doses. Degradation of carrageenan without serious loss of sulphate, gives a product which allows the dose to be increased to an extent that its effect more than offsets the slight loss in activity caused by the degradation. No single feature of carrageenan structure can be related to anti-ulcer activity although degradation, and hence reduction of molecular size, generally reduces activity. Sulphate contents over 30% have little apparent effect on activity; κ-carrageenans were not consistently different in anti-ulcer activity from Λ-carrageenans. This contrasts with the antipeptic activity of carrageenans where κ-carrageenans are less active than their Λ-counter-parts. As with antipeptic activity, the degree of anti-ulcer activity is probably determined by a combination of structural features which includes molecular size and polyanionic properties.  相似文献   

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Larks and owls and health, wealth, and wisdom   总被引:1,自引:0,他引:1  
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Depression and anxiety frequently coexist in patients with substance use disorders. This clinically-oriented article examiens the relationship between these conditions and emphasizes data showing that substances of abuse can cause signs and symptoms of both depression and anxiety. These substance-related syndromes appear to have a different course and prognosis than uncomplicated, independent anxiety and major depressive disorders, and clinicians should consider the role of alcohol and other drugs in all patients presenting with these complaints. The authors will also outline an approach for diagnosing and managing patients with the combination of a substance use and depressive or anxiety disorder.  相似文献   

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No abstract available for this article.  相似文献   

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The synthesis of gaultherin (1) and its analogs was carried out to provide 11 glycosides under phase-transfer catalytic conditions. The activities of all synthesized compounds were evaluated by nitric oxide production inhibitory assay in vitro. Methyl 2-O-(4-O-β-d-galactopyranosyl)-β-d-glucopyranosylbenzoate (5f) showed significantly anti-nociceptive and anti-inflammatory effects by the evaluation in vivo. Structure–activity relationships within these compounds were discussed.  相似文献   

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The American Chemical Society Symposium "Glucosidase and fucosidase inhibitors" took place on 1 April 1998 and was organized by Professors Zbigniew J Witczak (UConn, School of Pharmacy, CT, USA), Kuniaki Tatsuta (Waseda University, Tokyo, Japan) and Waldemar Priebe, MD (Anderson Cancer Center, University of Texas, USA). Professor Witczak provided introductory remarks including the status of existing glucosidase inhibitors, and chaired the morning session, which consisted of six lectures. The symposium was well received, and was particularly attractive for those interested in networking, as attendance was about sixty. In addition, some participants and attendees presented posters on the subject during the regular poster session organized by the Division of Carbohydrate Chemistry.  相似文献   

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The synthesis of gaultherin (1) and its analogs was carried out to provide 11 glycosides under phase-transfer catalytic conditions. The activities of all synthesized compounds were evaluated by nitric oxide production inhibitory assay in vitro. Methyl 2-O-(4-O-β-d-galactopyranosyl)-β-d-glucopyranosylbenzoate (5f) showed significantly anti-nociceptive and anti-inflammatory effects by the evaluation in vivo. Structure-activity relationships within these compounds were discussed.  相似文献   

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Dietary vitamin E and selenium and toxicity of nitrite and nitrate   总被引:4,自引:0,他引:4  
Chow CK  Hong CB 《Toxicology》2002,180(2):195-207
Nitrites and nitrates are important antimicrobial and flavoring/coloring agents in meat and fish products. However, nitrites and nitrates may cause methemoglobinemia and other illness, and may react with certain amines to form carcinogenic nitrosamines. The nutritional status of vitamin E and selenium has long been associated with nitrite and nitrate toxicity, although the mechanism involved is not yet clear. Information available recently shows that nitrites and nitrates are both oxidation products and ready sources of nitric oxide (NO*), that NO* reacts rapidly with superoxide to form highly reactive peroxynitrite (ONOO-), and that vitamin E may mediate the generation and availability of superoxide and NO*. Increased formation of ONOO- resulting from nitrite treatment and low intake of vitamin E and selenium may thus be the critical event leading to tissue damage and animal mortality observed previously. The protection against the adverse effects of nitrites/nitrates by vitamin E is attributed to its ability to reduce ONOO- formation, while selenium exerts its protective effects via seleno-enzymes/compounds, which reduce ONOO- formed.  相似文献   

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A new approach to the activation of components of the condensation of aromatic aldehydes with cyclohexanone, functioning as a receptor for the CH-acid component, is demonstrated. The condensation was performed in the presence of excess phosphorus oxychloride with heating and formed the corresponding 2,6-dibenzylidenecyclohexanone derivatives at high yield. The antiradical and antioxidant activities of the resulting compounds were assessed and cycvalon was found to have the greatest activity. The reference compound (dibunol) did not quench free radicals and had less antioxidant activity than cycvalon. __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 41, No. 8, pp. 7–10, August, 2007.  相似文献   

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益生菌广泛存在于自然界中,通过维持宿主体内菌群平衡、影响肠屏障功能和调节免疫应答等作用,提高宿主健康水平,被公认为"肠道健康卫士".一些益生菌可以增强机体的免疫功能,抑制致癌物质,影响肿瘤细胞的基因表达,对肿瘤具有拮抗作用.大量研究表明,益生菌在未来的肿瘤防治中有很好的应用和发展前景.  相似文献   

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骨质疏松是一种全身性骨骼疾病,导致骨折风险增加。成人的骨量通过破骨细胞的骨吸收和成骨细胞的骨形成作用来维持动态平衡,治疗骨质疏松症的理想策略是抑制破骨细胞的骨吸收和/或增强成骨细胞的骨形成功能。目前针对保护成骨细胞及增强其功能的骨质疏松疗法相对较少。因此,本文针对成骨细胞相关功能蛋白、各种细胞损伤机制(内质网应激、氧化应激、机械过载、微小RNA和长链非编码RNA的影响等)及骨质疏松的治疗与预防作一综述,以期为针对增强成骨细胞功能的骨质疏松治疗策略提供新思路。  相似文献   

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