检索结果-南通市图书馆

Concentrated Extract of Green Tea Polyphenols Enhances the Toxicity of the Elderberry Lectin nigrin b to Mice

Food and nutrition Sciences 2014年第5期5卷 466-471页

作者： Pilar Jiménez Patricia Cabrero Jesús Tejero Manuel J. Gayoso Manuel Garrosa damián cordoba-diaz Manuel cordoba-diaz Tomás Girbés Biología Celular Histología y Farmacología Facul- tad de Medicina and INCYL (Instituto de Neurociencias de Castilla y León) Universidad de Valladolid Valladolid Spain Farmacia y Tecnología Farmacéutica Facultad de Farmacia and IUFI (Instituto Universitario de Farmacia Industrial) Universidad Complu- tense de Madrid Madrid Spain nutrición y Bromatología Facultad de Medicina and CINAD (Centro de Investigación en Nutrición Alimentación y Dietética Edi- ficio LUCIA-Parque Científico) Universidad de Valladolid Valladolid Spain nutrición y Bromatología Facultad de Medicina and CINAD (Centro de Investigación en Nutrición Alimentación y Dietética Edi- ficio LUCIA-Parque Científico) Universidad de Valladolid Valladolid Spain

The effect of the administration of large amounts of green tea polyphenols is a matter of controversy. We explored whether a polyphenol mixture from a concentrated green tea extract (Polyphenon 60) could alter the effects on mice of the type 2 (two chains) ribosome-inactivating protein nigrin b isolated from Sambucus nigra L. nigrin b triggers specific reversible toxic effects on the mouse intestines featured by apoptosis of mice Lieberkühn crypt cells upon parenteral administration of sub-lethal amounts. Independent administration to mice of 30 mg/kg body weight of Polyphenon 60 by oral gavage or 10 mg/kg body weight of nigrin b administered via the intraperitoneal route (i.p.) did not affect survival. In contrast, the simultaneous treatment greatly enhanced nigrin b toxicity leading to the death of some animals. The histological analysis revealed that the most serious injury was inflicted on the small intestine crypts, which disappeared, and on the liver, which evidenced hepatotoxicity showing haemorrhagic areas. These findings raise concerns about the abuse of high concentrations of green tea polyphenols especially when the intestinal mucosa is damaged, for instance by toxins or therapeutic drugs.

关键词： Green Tea Polyphenols nigrin b Model Ribosome-Inactivating Protein Lectin Small Intestine Liver Apoptosis

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Plasma Accumulations of Vitamin B6 from an Oral Dose in a new Reversible Model for Mouse Gut Injury and Regeneration

引用

Food and nutrition Sciences 2013年第9期4卷 908-917页

作者： Pilar Jiménez damián cordoba-diaz Patricia Cabrero Mónica Aracil Manuel J. Gayoso Manuel Garrosa Manuel cordoba-diaz Tomás Girbés Biología Celular Histología y Farmacología Facultad de Medicina and INCYL (Instituto de Neurociencias de Castilla y León) Universidad de Valladolid Valladolid Spain. Farmacia y Tecnología Farmacéutica Facultad de Farmacia and IUFI (Instituto Universitario de Farmacia Industrial) Universidad Complutense de Madrid Madrid Spain nutrición y Bromatología Facultad de Medicina and CINAD (Centro de Investigación en Nutrición Alimentación y Dietética- Edificio LUCIA-Parque Científico) Universidad de Valladolid Valladolid Spain

Chemically based rodent models are used to assess the positive effects promoted by foods and gut microbiota on gut health. Lectins with enzymatic activity, such as type 2 ribosome-inactivating proteins, might also prove useful for exploring these issues. Sub-lethal doses of the lectin nigrin from Sambucus nigra L. to mice promoted reversible derangement of gut epithelium by induction of apoptosis of transit amplifying cells of the small intestine crypts in a time-dependent course. The present work seeks to study vitamin B6 accumulation in plasma from an oral bolus in a mouse nigrin model. 24 h after sub-lethal nigrin b treatment, there was clear body weight reduction associated to a notable increase in Evan’s blue stain accumulation in excised small intestine, an increase in myeloperoxidase activity, and a near 50% reduction in plasma accumulation of vitamin B6. Histological analysis of small intestine sections of nigrin b-treated animals also revealed significant derangement of intestinal crypts. Seventy two hours after nigrin b treatment, stain uptake decreased and vitamin B6 accumulation was almost restored despite villi derangement. Large intestine crypts were scarcely or not at all affected. Eight days after nigrin b treatment, vitamin B6 uptake and intestinal crypt structure had fully recovered. The nigrin b mice model supports the view that, under these conditions, the carrier-mediated vitamin B6 uptake component of the small intestine crypts is probably the most active when the vitamin is administered orally as a bolus. The findings provide insights into the suitability of the present mice model for nutritional or drug absorption studies in conditions of partially altered or injured intestinal mucosa.

关键词： Vitamin B6 nigrin b Ribosome-Inactivating Protein Sambucus Ricin Intestines Mice Model

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Comparative Analysis of the Antioxidant and Free-Radical Scavenging Activities of Different Water-Soluble Extracts of Green, Black and Oolong Tea Samples

引用

Food and nutrition Sciences 2014年第22期5卷 2157-2166页

作者： Jesús Tejero Sara Gayoso Irma Caro damián cordoba-diaz Javier Mateo José E. Basterrechea Tomás Girbés Pilar Jiménez nutrició n y Bromatologí a Facultad de Medicina and CINAD (Centro de Investigaci&oacute n en nutrició n Alimentaci&oacute n y Dietética Edificio Lucia-Parque Cientí fico) Universidad de Valladolid Valladolid Spain Farmacia y Tecnologí a Farmacéutica Facultad de Farmacia and IUFI (Instituto Universitario de Farmacia Industrial) Universidad Complutense de Madrid Madrid Spain Higiene de los Alimentos y Tecnologí a Facultad de Veterinaria Universidad de Le&oacute n Le&oacute n Spain

Extracts of 40 green, black or oolong high quality tea samples from China, Japan or India among others, have been prepared according to the manufacturer instructions and assayed for total polyphenols content using the Folin-Ciocalteu phenol reagent. In addition, the antioxidant activity was assessed by the CUPRAC method and the free-radical scavenging activity was determined using the antioxidant-promoting decay of the stable free-radical DPPH. Caffeine and the most important catechins were identified using RP-HPLC previously validated method. Results from this study suggest that teas, even though they content similar amounts of caffeine, differ considerably in polyphenolic content and therefore in antioxidant and free-radical scavenging activities, depending on the part of the plant used and the process applied to the material for the preparation of the final tea presentation. Correlations among Folin-Ciocalteau’s reactivity of tea samples, the neocuproine reactivity, the DPPH decolourization and the HPLC analysis suggest that the antioxidant activity is due essentially to polyphenolic compounds present in teas, mainly EGCG. The best extraction method of tea powder was the one indicated by dealers. In general, the richest samples belong to green teas and the poorest samples belong to the black teas.

关键词： Tea Polyphenols Antioxidants Free-Radical Scavenging

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Changes in Olsen P in Relation to P Balance in Contrasting Agricultural Soils

引用

Pedosphere 2016年第5期26卷 636-642页

作者： Isabel diaz Jose TORREnT Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos Escuela Tdcnica Superior de Ingeniería Agronómica(ETSIA)Universidad de SevillaCtra de Utrera km 141013 Sevilla(Spain) Departamento de Agronomia Universidad de CordobaEdificio C4Campus de Rabanales14071 Cordoba(Spain)

Maintaining soil phosphorus （P） at adequate levels for plant growth requires assessing how the long-term P balance （viz., the difference between P inputs and outputs） results in changes in soil test P. The hypothesis that routinely measured soil properties can help predict the conversion factor of P balance into Olsen P was tested at 39 sites in agricultural areas of the Mediterranean region in Spair~. A set of soil samples from each site was analyzed for Olsen P, inorganic P （P extracted using 0.5 mol L-1 H2SO4）, pseudototal P （P extracted using 0.5 mol L-1 H2SO4 following ignition at 550 ~C）, and organic P （the difference between pseudototal P and inorganic P）. Organic and Olsen P were uncorrelated in most of the 39 soil sets, which suggests that organic P content changed little with P inputs and outputs. The slopes of the regression lines of Olsen P against pseudototal and inorganic P, which were used as two different measures of the conversion factor, ranged widely （from 0.03 to 0.25 approximately）, with their average values （about 0.10） being similar to those found in long-term experiments conducted in temperate areas. neither conversion factor was significantly correlated with any routinely measured soil property; however, the conversion factor for inorganic P was significantly lower for calcareous soils than for noncalcareous soils. Our negative results suggest the need to isolate the influence of soil properties from that of management systems and environmental factors relating to P dynamics in future studies.

关键词： calcareous soils conversion factor inorganic P noncalcareous soils organic P pseudototal P soil property soil test P

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Loop-Shaping Based Control for Switch Mode DC-DC Power Converters

引用

Journal of Power and Energy Engineering 2020年第10期8卷 66-83页

作者： Ma Guadalupe Ortiz-Lopez Luis Humberto diaz-Saldierna Diego Langarica-cordoba Jesus Leyva-Ramos Universidad Politecnica de San Luis Potosí San Luis Potosí Mexico Instituto Potosino de Investigación Cientifica y Tecnologica San Luis Potosí Mexico Universidad Autonoma de San Luis Potosi San Luis Potosí Mexico

Renewable energy sources require switching regulators as an interface to a load with high efficiency, small size, proper output regulation, and fast transient response. Moreover, due to the nonlinear behavior and switching nature of DC-DC power electronic converters, there is a need for high-performance control strategies. This work summarized the dynamic behavior for the three basic switch-mode DC-DC power converters operating in continuous conduction mode, n>i.e. buck, boost, and buck-boost. A controller was designed using loop-shaping based on current-mode control that consists of two feedback loops. A high-gain compensator with wide bandwidth was used in the inner current loop for fast transient response. A proportional-integral controller was used in the outer voltage loop for regulation purposes. A procedure was proposed for the parameters of the controller that ensures closed-loopn style="font-family:Verdana;"> stability and output voltage regulation. The design-oriented analysis was applied to the three basic switch-mode DC-DC power converters. Experimental results were obtained for a switching regulator with a boost converter of 150 W, which exhibits non-minimum phase behavior. The performance of the controller was tested for voltage regulation by applying large load changes.

关键词： Renewable Energy Sources Loop-Shaping Control Power Electronic Converters Current-Mode Control

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Precipitating factors leading to decompensation of chronic heart failure in the elderly patient in South-American community hospital

引用

Journal of Geriatric Cardiology 2011年第1期8卷 12-14页

作者： Alejandro diaz Cleto Ciocchini Mariano Esperatti Alberto Becerra Sabrina Mainardi Alejandro Farah Department of Cardiology Hospital Privado de Comunidad Cordoba 4545 Mar del Plata 7600 Argentina Department of Internal Medicine Hospital Privado de Comunidad Cordoba 4545 Mar del Plata 7600 Argentina

Background Exacerbations of heart failure appear frequently associated with precipitating factors not directly related to the evolution of cardiac disease. There still a paucity of data on the proportional distribution of precipitating factors specifically in elderly patients. The aim of this study was to examine prospectively the precipitating factors leading to hospitalization in elderly patients with heart failure in our community hospital. Methods We evaluate elderly patients who need admissions for decompensate heart failure. All patients were reviewed daily by the study investigators at the first 24 h and closely followed-up. Decompensation was defined as the worsening in clinical nYHA class associated with the need for an increase in medical treatment （at minimum intravenously diuretics）. Results We included 102 patients （mean age 79 ± 12 years）. Precipitating factors were identified in 88.5%. The decompensation was sudden in 35% of the cases. noncompliance with diet was identified in 52% of the patients, lack of adherence to the prescribed medications amounted to 30%. Others precipitating factors were infections （29%）, arrhythmias （25%）, acute coronary ischemia （22%）, and uncontrolled hypertension （15%）, miscellaneous causes were detected in 18% of the cases （progression of renal disease 60%, anemia 30% and iatrogenic factors 10%）. Concomitant cause was not recognizable in 11.5%. Conclusions Large proportion heart failure hospitalizations are associated with preventable precipitating factors. Knowledge of potential precipitating factors may help to optimize treatment and provide guidance for patients with heart failure. The presence of potential precipitating factors should be routinely evaluated in patients presenting chronic heart failure.

关键词： heart failure exacerbation elderly patient

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：