68 results for “HPLC”

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Research ArticleOpen accessIn the abstractBioconversion of Carotenoids in Five Fruits and Vegetables to Vitamin A Measured by Retinol Accumulation in Rat LiversArmando Carrillo-Lopez, Elhadi M. Yahia, Gabriela K. Ramirez-PadillaProblem statement: Vitamin A deficiency is one of the most prevalent and major nutritional problems in developing countries, especially in young children. In many countries, a substantial proportion of dietary vitamin A is commonly derived from pro-vitamin A carotenoids obtained from colored fruits and orange or green vegetables. However, the bioavailability of retinol derived from carotenoids from these plant sources … …American Journal of Agricultural and Biological Sciences, Vol. 5, Issue 2 · 30 Jun 2010 · 8,926 accessesView PDF Cite

Research ArticleOpen accessIn the abstractProfiling of Phenolic Compounds of Somatic and Reproductive Tissues of Agave Durangensis Gentry (Agavaceae)Norma Almaraz-Abarca, Elí Amanda Delgado-Alvarado, Vicente Hernández-Vargas et al.Problem statement: In Durango, Mexico, mescal is elaborated from wild plants of Agave durangensis. This species shows a high morphological variability within and among populations, what makes its taxonomic delimitation a hard task. Approach: In this study the pollen and foliar phenolic compositions of Agave durangensis were analyzed by HPLC/DAD with the aim of determining the significance of phenol profiles … …American Journal of Applied Sciences, Vol. 6, Issue 6 · 30 Jun 2009 · 7,740 accessesView PDF Cite

Research ArticleOpen accessIn the abstractProtective Effects of Covalent Cross-Linking on Proteolysis of Human Coproporphyrinogen Oxidase and Implications for PorphyriaAhmed W. Jafri, Jason R. Stephenson, Justin B. Morgenthaler et al.The effects of covalent cross-linkers on the enzyme, coproporphyrinogen oxidase, had been previously studied but their role in protecting the enzyme from protease cleavage has not been evaluated. Therefore, we examined how the cross-linker bis (sulfosuccinimidyl) suberate (BS3) affects the ability of trypsin to digest purified, wild type recombinant human coproporphyrinogen oxidase and selected mutants. Following incubation, the apparent molecular … …American Journal of Biochemistry and Biotechnology, Vol. 4, Issue 4 · 31 Dec 2008 · 6,687 accessesView PDF Cite

Research ArticleOpen accessIn the abstractPollen Flavonoid/Phenolic Acid Composition of Four Species of Cactaceae and its Taxonomic SignificanceNorma Almaraz-Abarca, MarÍa G. Campos, Elí A. Delgado-Alvarado et al.The pollen flavonoid/phenolic acid composition of 14 individual of Stenocactus multicostatus subsp. zacatecasensis (Britton et Rose) U. Guzmán et Vázquez-Benitez, comb. et stat. nov., 11 of Echinocereus enneacanthus Engelmann, 8 of Echinocereus pectinatus (Scheidweiler) Engelmann and 12 of Mammillaria heyderi sensu lato (all belonging to Cactaceae) was analyzed by HPLC/DAD with the aim of determining the role of pollen profiles … …American Journal of Agricultural and Biological Sciences, Vol. 3, Issue 3 · 30 Sep 2008 · 8,450 accessesView PDF Cite

Research ArticleOpen accessIn the abstractComparative Permeation Studies between Scale Region of Shed Snake Skin and Human Skin In vitroAroonsri Priprem, Chidchanok Khamlert, Thaned Pongjanyakul et al.Scales of shed king cobra (Ophiophagus hannah) skin from the dorsal portions, (SSS) and human breast epidermis (HE) were used as barrier membranes for comparison in an in vitro drug permeation study of nine active compounds (MW range 150-300 g mol-1, pKa 3-10). Each compound, saturated in a donor solution at pH 4.0 or 5.6, permeated through the barrier membrane, … …American Journal of Agricultural and Biological Sciences, Vol. 3, Issue 1 · 31 Mar 2008 · 8,413 accessesView PDF Cite

Research ArticleOpen accessIn the abstractHIV-1 Infection and Central Monoamine NeurotransmittersAdarsh M. Kumar, J. B. Fernandez, Irina Borodowsky et al.Human immunodeficiency virus type 1 (HIV-1) enters the central nervous system (CNS) shortly after infection and gets localized in different brain regions, leading to various types of neuropathological problems. It has been hypothesized that HIV-1 infection mediated neuropathogenesis may also adversely affect the activity of the central monoamine neurotransmitters systems, such as dopamine (DA), and 5-hydroxytryptamine (5-HT, serotonin), resulting in … …American Journal of Infectious Diseases, Vol. 3, Issue 4 · 31 Dec 2007 · 7,491 accessesView PDF Cite

Research ArticleOpen accessIn the abstractShed Skin of Ophiophagus hannah: Structural Topography and In Vitro Permeation of Nicotine and PhenolA. Priprem, T. Pongjanyakul, C. Khamlert et al.Scales of the dorsal portions of shed skin of king cobras (Ophiophagus hannah) was used as the barrier membrane for in vitro permeation of nicotine and phenol at toxic or irritable concentration levels. The scales were placed between solutions of nicotine or phenol in a donor solution at pH 5.6 and a receptor solution at pH 7.4. Cumulative amounts of … …American Journal of Animal and Veterinary Sciences, Vol. 2, Issue 4 · 31 Dec 2007 · 6,735 accessesView PDF Cite

Research ArticleOpen accessIn the abstractUse of Cross-linking to Assess Subunit Interaction of Recombinant Human Coproporphyrinogen OxidaseJason R. Stephenson, Nancy E. Thomas, Jon A. Friesen, Marjorie A. JonesTo provide further evidence for a dimeric form of coproporphyrinogen oxidase reported using the conventional hydrodynamic methods, bifunctional cross-linkers were incubated with purified, recombinant human coproporphyrinogen oxidase to determine subunit interaction in solution. The use of cross-linkers provides an effective way to demonstrate subunit association and allows for assessment of activity upon covalent cross-linking. Following incubation with selected cross-linkers, enzyme … …American Journal of Biochemistry and Biotechnology, Vol. 1, Issue 2 · 30 Jun 2005 · 6,594 accessesView PDF Cite