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2.
J Food Sci ; 74(6): C456-61, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19723182

RESUMO

Little is known about the effects of common cooking processes on cocoa flavanols. Antioxidant activity, total polyphenols (TP), flavanol monomers, and procyanidin oligomers were determined in chocolate frosting, a hot cocoa drink, chocolate cookies, and chocolate cake made with natural cocoa powder. Recoveries of antioxidant activity, TP, flavanol monomers, and procyanidins ranged from 86% to over 100% in the chocolate frosting, hot cocoa drink, and chocolate cookies. Losses were greatest in the chocolate cake with recoveries ranging from 5% for epicatechin to 54% for antioxidant activity. The causes of losses in baked chocolate cakes were investigated by exchanging baking soda with baking powder or combinations of the 2 leavening agents. Use of baking soda as a leavening agent was associated with increased pH and darkening color of cakes. Losses of antioxidant activity, TP, flavanol monomers, and procyanidins were associated with an increased extractable pH of the baked cakes. Chocolate cakes made with baking powder for leavening resulted in an average extractable pH of 6.2 with essentially complete retention of antioxidant activity and flavanol content, but with reduced cake heights and lighter cake color. Commercially available chocolate cake mixes had final pHs above 8.3 and contained no detectable monomeric flavanols after baking. These results suggest that baking soda causes an increase in pH and subsequent destruction of flavanol compounds and antioxidant activity. Use of an appropriate leavening agent to moderate the final cake pH to approximately 7.25 or less results in both good leavening and preservation of cocoa flavanols and procyanidins.


Assuntos
Antioxidantes/química , Cacau/química , Flavonoides/análise , Flavonóis/análise , Manipulação de Alimentos/métodos , Fenóis/análise , Proantocianidinas/análise , Algoritmos , Compostos de Alúmen/química , Sulfato de Cálcio/química , Livros de Culinária como Assunto , Frutas/química , Temperatura Alta , Concentração de Íons de Hidrogênio , Polifenóis , Espécies Reativas de Oxigênio/química , Bicarbonato de Sódio/química , Amido/química
3.
Tissue Antigens ; 63(6): 602-5, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15140043

RESUMO

We describe a new human leukocyte antigen (HLA)-Cw*07 allele that differs from Cw*0718 by a single-coding nucleotide. DNA-based genotyping identified a clinical sample from a Black African-American patient that differed from known Cw alleles. The allele was amplified independently with a haplo-specific primer and sequenced in its entirety.


Assuntos
Antígenos HLA-C/genética , Éxons , Humanos , Íntrons , Dados de Sequência Molecular , Análise de Sequência de DNA
4.
J Immunol ; 166(10): 5979-90, 2001 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-11342613

RESUMO

The interaction between human IgE and its high affinity receptor, FcepsilonRI, is a critical event in mediating the allergic response. Aggregation of the alpha-chain of FcepsilonRI (FcepsilonRIalpha) occurs via cross-linking of receptor-bound IgE by Ag, resulting in cell activation and the release of mediators of hypersensitivity. Recently, we mapped the epitopes of two anti-FcepsilonRIalpha mAbs, 15/1 and 5H5F8. In contrast to 15/1, mAb 5H5F8 does not inhibit IgE binding to FcepsilonRIalpha. Here we demonstrate both 5H5F8 binding to FcepsilonRI(+) cells as well as a high level of IgE binding to 5H5F8-saturated cells. At the same time 5H5F8 strongly inhibits hexosaminidase release and Ca(2+) flux after Ag triggering from human IgE-sensitized RBL-2H3 cells stably transfected with human FcepsilonRIalpha. Further, 5H5F8 and its Fab inhibit sulfidoleukotriene and histamine release from primary human peripheral blood leukocytes, including cells bearing endogenous IGE: Furthermore, we confirm that 5H5F8 maps to a linear peptide sequence in close proximity to the cell membrane. Two chemically synthesized peptides containing the 5H5F8 epitope sequence PREKY were selected for detailed analysis of 5H5F8 and 5H5F8 Fab binding and were found to produce K(d) values of similar magnitude to that observed for binding to recombinant FcepsilonRIalpha. These peptides may prove useful as targets for the identification of antagonists of FcepsilonRIalpha-mediated biological activity. Moreover, our data indicate that FcepsilonRIalpha-mediated activation may involve a novel alpha-chain epitope in an early step of the cell-triggering pathway leading to cellular activation.


Assuntos
Anticorpos Monoclonais/farmacologia , Antígenos/imunologia , Basófilos/imunologia , Basófilos/metabolismo , Imunoglobulina E/metabolismo , Antagonistas de Leucotrienos , Fragmentos de Peptídeos/imunologia , Receptores de IgE/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/metabolismo , Basófilos/enzimologia , Sítios de Ligação de Anticorpos/genética , Ligação Competitiva/genética , Células CHO , Cálcio/metabolismo , Membrana Celular/imunologia , Membrana Celular/metabolismo , Cricetinae , Epitopos/química , Epitopos/imunologia , Epitopos/metabolismo , Antagonistas dos Receptores Histamínicos/metabolismo , Antagonistas dos Receptores Histamínicos/farmacologia , Liberação de Histamina/imunologia , Humanos , Imunoglobulina E/genética , Imunoglobulina E/fisiologia , Fragmentos Fab das Imunoglobulinas/metabolismo , Líquido Intracelular/metabolismo , Cinética , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Leucotrienos/metabolismo , Camundongos , Dados de Sequência Molecular , Nitrofenóis/imunologia , Fragmentos de Peptídeos/síntese química , Fragmentos de Peptídeos/metabolismo , Fragmentos de Peptídeos/fisiologia , Fenilacetatos , Ratos , Receptores de IgE/metabolismo , Receptores de IgE/fisiologia , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/metabolismo , Transfecção , Células Tumorais Cultivadas , beta-N-Acetil-Hexosaminidases/antagonistas & inibidores , beta-N-Acetil-Hexosaminidases/metabolismo
5.
Mol Biol Cell ; 11(10): 3661-73, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11029062

RESUMO

Characterization of defects in a variant subline of RBL mast cells has revealed a biochemical event proximal to IgE receptor (Fc epsilon RI)-stimulated tyrosine phosphorylation that is required for multiple functional responses. This cell line, designated B6A4C1, is deficient in both Fc epsilon RI-mediated degranulation and biosynthesis of several lipid raft components. Agents that bypass receptor-mediated Ca(2+) influx stimulate strong degranulation responses in these variant cells. Cross-linking of IgE-Fc epsilon RI on these cells stimulates robust tyrosine phosphorylation but fails to mobilize a sustained Ca(2+) response. Fc epsilon RI-mediated inositol phosphate production is not detectable in these cells, and failure of adenosine receptors to mobilize Ca(2+) suggests a general deficiency in stimulated phospholipase C activity. Antigen stimulation of phospholipases A(2) and D is also defective. Infection of B6A4C1 cells with vaccinia virus constructs expressing constitutively active Rho family members Cdc42 and Rac restores antigen-stimulated degranulation, and active Cdc42 (but not active Rac) restores ganglioside and GPI expression. The results support the hypothesis that activation of Cdc42 and/or Rac is critical for Fc epsilon RI-mediated signaling that leads to Ca(2+) mobilization and degranulation. Furthermore, they suggest that Cdc42 plays an important role in the biosynthesis and expression of certain components of lipid rafts.


Assuntos
Metabolismo dos Lipídeos , Mastócitos/fisiologia , Receptores de IgE/fisiologia , Proteínas rho de Ligação ao GTP/metabolismo , Actinas/metabolismo , Animais , Cálcio/metabolismo , Linhagem Celular , Grânulos Citoplasmáticos/genética , Grânulos Citoplasmáticos/ultraestrutura , Ativação Enzimática , Immunoblotting , Cinética , Leucemia Basofílica Aguda , Mastócitos/citologia , Fosforilação , Fosfotirosina/análise , Fosfotirosina/metabolismo , Ratos , Transdução de Sinais
6.
J Immunol ; 165(4): 2156-64, 2000 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-10925302

RESUMO

Galectin-3 is a beta-galactoside-binding protein implicated in diverse biological processes. We found that galectin-3 induced human monocyte migration in vitro in a dose-dependent manner, and it was chemotactic at high concentrations (1.0 microM) but chemokinetic at low concentrations (10-100 nM). Galectin-3-induced monocyte migration was inhibited by its specific mAb and was blocked by lactose and a C-terminal domain fragment of the protein, indicating that both the N-terminal and C-terminal domains of galectin-3 are involved in this activity. Pertussis toxin (PTX) almost completely blocked monocyte migration induced by high concentrations of galectin-3. Galectin-3 caused a Ca2+ influx in monocytes at high, but not low, concentrations, and both lactose and PTX inhibited this response. There was no cross-desensitization between galectin-3 and any of the monocyte-reactive chemokines examined, including monocyte chemotactic protein-1, macrophage inflammatory protein-1alpha, and stromal cell-derived factor-1alpha. Cultured human macrophages and alveolar macrophages also migrated toward galectin-3, but not monocyte chemotactic protein-1. Finally, galectin-3 was found to cause monocyte accumulation in vivo in mouse air pouches. These results indicate that galectin-3 is a novel chemoattractant for monocytes and macrophages and suggest that the effect is mediated at least in part through a PTX-sensitive (G protein-coupled) pathway.


Assuntos
Antígenos de Diferenciação/fisiologia , Fatores Quimiotáticos/fisiologia , Macrófagos/imunologia , Monócitos/imunologia , Animais , Antígenos de Diferenciação/administração & dosagem , Antígenos de Diferenciação/metabolismo , Cálcio/metabolismo , Inibição de Migração Celular , Movimento Celular/imunologia , Células Cultivadas , Quimiocina CCL2/fisiologia , Fatores Quimiotáticos/administração & dosagem , Fatores Quimiotáticos/metabolismo , Quimiotaxia de Leucócito/imunologia , Cultura em Câmaras de Difusão , Relação Dose-Resposta Imunológica , Galectina 3 , Humanos , Injeções Intradérmicas , Líquido Intracelular/metabolismo , Cinética , Macrófagos Alveolares/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Monócitos/metabolismo , Monócitos/patologia , Toxina Pertussis , Estrutura Terciária de Proteína , Receptores de Quimiocinas/fisiologia , Transdução de Sinais/imunologia , Pele/imunologia , Pele/patologia , Fatores de Virulência de Bordetella/farmacologia
7.
Biophys J ; 79(2): 1095-106, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10920039

RESUMO

One of the central functions of actin cytoskeleton is to provide the mechanical support required for the establishment and maintenance of cell morphology. The mechanical properties of actin filament assemblies are a consequence of both the available polymer concentration and the actin regulatory proteins that direct the formation of higher order structures. By monitoring the displacement of well-dispersed microspheres via fluorescence microscopy, we probe the degree of spatial heterogeneity of F-actin gels and networks in vitro. We compare the distribution of the time-dependent mean-square displacement (MSD) of polystyrene microspheres imbedded in low- and high-concentration F-actin solutions, in the presence and absence of the F-actin-bundling protein fascin. The MSD distribution of a 2. 6-microM F-actin solution is symmetric and its standard deviation is similar to that of a homogeneous solution of glycerol of similar zero-shear viscosity. However, increasing actin concentration renders the MSD distribution wide and asymmetric, an effect enhanced by fascin. Quantitative changes in the shape of the MSD distribution correlate qualitatively with the presence of large heterogeneities in F-actin solutions produced by increased filament concentration and the presence of actin bundles, as detected by confocal microscopy. Multiple-particle tracking offers a new, quantitative method to characterize the organization of biopolymers in solution.


Assuntos
Actinas/química , Actinas/ultraestrutura , Actinas/fisiologia , Animais , Galinhas , Citoesqueleto/fisiologia , Microscopia Confocal/métodos , Microscopia de Fluorescência/métodos , Microesferas , Modelos Moleculares , Músculo Esquelético/fisiologia , Conformação Proteica , Soluções
8.
J Immunol ; 164(5): 2667-73, 2000 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-10679107

RESUMO

IgE is present in airway secretions from human patients with allergic rhinitis and bronchial asthma. However, the contribution of IgE present locally to the overall airway inflammation is not well understood. We hypothesize that Ag-specific IgE can capture airborne Ags and form immune complexes. These immune complexes may function as potent inducers of immune responses in the lung, contributing to the perpetuation of airway inflammation. BALB/c mice were first sensitized with OVA in alum systemically and then challenged with nebulized OVA. Bronchoalveolar lavage (BAL) fluid from these mice contained significant amounts of IgE, of which >50% was Ag specific. The IgE levels in airway secretions remained elevated for more than 15 days after the termination of Ag exposure. Significant amounts of IgE-OVA immune complexes were detected in BAL fluid from the OVA-challenged mice. For comparison of IgE immune complexes vs Ag alone, we treated OVA-immunized mice with intranasal administration of trinitrophenyl-OVA or trinitrophenyl-OVA-anti-DNP IgE. Those treated with the immune complexes showed significantly higher levels of IL-4 and more pronounced eosinophilia in BAL fluid than did those receiving the Ag alone. The IgE immune complexes did not augment the inflammatory response in high affinity IgE receptor (FcepsilonRI)-deficient mice. We conclude that IgE present in the airways can capture the Ag and that the immune complexes thus formed may augment allergic airway response in an FcepsilonRI-dependent manner. Thus, IgE present in airway secretions may facilitate Ag-mediated allergic airway inflammation.


Assuntos
Complexo Antígeno-Anticorpo/administração & dosagem , Antígenos/administração & dosagem , Imunoglobulina E/fisiologia , Pulmão/imunologia , Pulmão/metabolismo , Aerossóis , Animais , Especificidade de Anticorpos , Complexo Antígeno-Anticorpo/metabolismo , Complexo Antígeno-Anticorpo/fisiologia , Antígenos/metabolismo , Antígenos/fisiologia , Líquido da Lavagem Broncoalveolar/imunologia , Modelos Animais de Doenças , Feminino , Humanos , Imunoglobulina E/administração & dosagem , Imunoglobulina E/metabolismo , Inflamação/genética , Inflamação/imunologia , Inflamação/metabolismo , Pulmão/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Camundongos Transgênicos , Nebulizadores e Vaporizadores , Ovalbumina/administração & dosagem , Ovalbumina/imunologia , Ovalbumina/metabolismo , Receptores de IgE/deficiência , Receptores de IgE/genética , Hipersensibilidade Respiratória/genética , Hipersensibilidade Respiratória/imunologia , Hipersensibilidade Respiratória/metabolismo
9.
J Biol Chem ; 274(28): 19752-61, 1999 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-10391917

RESUMO

A fraction of Bruton's tyrosine kinase (Btk) co-localizes with actin fibers upon stimulation of mast cells via the high affinity IgE receptor (FcepsilonRI). In this study, a molecular basis of the Btk co-localization with actin fibers is presented. Btk and other Tec family tyrosine kinases have a pleckstrin homology (PH) domain at their N termini. The PH domain is a short peptide module frequently found in signal-transducing proteins and cytoskeletal proteins. Filamentous actin (F-actin) is shown to be a novel ligand for a subset of PH domains, including that of Btk. The actin-binding site was mapped to a 10-residue region of the N-terminal region of Btk. Basic residues in this short stretch are demonstrated to be involved in actin binding. Isolated PH domains induced actin filament bundle formation. Consistent with these observations, Btk binds F-actin in vitro and in vivo. Wild-type Btk protein is in part translocated to the cytoskeleton upon FcepsilonRI cross-linking, whereas Btk containing a mutated PH domain is not. Phosphatidylinositol 3,4, 5-trisphosphate-mediated membrane translocation of Btk was enhanced in cytochalasin D-pretreated, FcepsilonRI-stimulated mast cells. These data indicate that PH domain-mediated F-actin binding plays a role in Btk co-localization with actin filaments.


Assuntos
Actinas/química , Proteínas Tirosina Quinases/química , Tirosina Quinase da Agamaglobulinemia , Sequência de Aminoácidos , Androstadienos/farmacologia , Animais , Sítios de Ligação , Ligação Competitiva , Citocalasina D/farmacologia , Imunoglobulina E/imunologia , Mastócitos/metabolismo , Dados de Sequência Molecular , Fosfatidilinositol 4,5-Difosfato/metabolismo , Fosfatos de Fosfatidilinositol/farmacologia , Proteína Quinase C/metabolismo , Ratos , Receptores de IgE/metabolismo , Wortmanina , Domínios de Homologia de src
10.
J Immunol ; 162(4): 2243-50, 1999 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-9973500

RESUMO

Cross-linking of FcepsilonRI on rat basophilic leukemia (RBL) cells initiates a signaling cascade leading to degranulation of the cells and the release of inflammatory mediators. Inhibitors that disrupt microfilaments, such as latrunculin and cytochalasin D, do not cause any degranulation on their own, but they do enhance FcepsilonRI-mediated degranulation. Dose-response studies show a good correlation between inhibition of actin polymerization and increased degranulation. In RBL cells, latrunculin causes a decrease in basal levels of filamentous actin (F-actin), while cytochalasin D does not. This is particularly evident in the Triton-insoluble pool of F-actin which is highly cross-linked and associated with the plasma membrane. A concentration of 500 nM latrunculin decreases the basal level of Triton-insoluble F-actin by 60-70% and total F-actin levels by 25%. Latrunculin increases both the rate and extent of Ag-induced degranulation while having no effect on pervanadate-induced degranulation. Pervanadate activates the signaling pathways directly and bypasses the cross-linking of the receptor. RBL cells, activated through FcepsilonRI in the presence of latrunculin, show increased phospholipase activity as well as increased tyrosine phosphorylation of Syk and increased tyrosine phosphorylation of the receptor itself by the tyrosine kinase Lyn. This indicates that the very earliest signaling events after receptor cross-linking are enhanced. These results suggest that actin microfilaments may interact, either directly or indirectly, with the receptor itself and that they may regulate the signaling process at the level of receptor phosphorylation. Microfilaments may possibly act by uncoupling Lyn from the cross-linked receptor.


Assuntos
Citoesqueleto de Actina/fisiologia , Actinas/fisiologia , Degranulação Celular/imunologia , Regulação para Baixo/imunologia , Mastócitos/fisiologia , Citoesqueleto de Actina/efeitos dos fármacos , Actinas/antagonistas & inibidores , Animais , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Degranulação Celular/efeitos dos fármacos , Citocalasina D/farmacologia , Dinitrofenóis/imunologia , Relação Dose-Resposta Imunológica , Regulação para Baixo/efeitos dos fármacos , Haptenos/imunologia , Leucemia Basofílica Aguda , Toxinas Marinhas/farmacologia , Mastócitos/efeitos dos fármacos , Mastócitos/imunologia , Poríferos , Ratos , Receptores de IgE/fisiologia , Soroalbumina Bovina/imunologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/imunologia , Tiazóis/farmacologia , Tiazolidinas , Células Tumorais Cultivadas
11.
J Microsc ; 191(Pt 1): 20-7, 1998 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9723188

RESUMO

The fluorescence pattern induced by haematoxylin-eosin (HE) and Masson's trichrome (MT) staining methods on paraffin sections of rat embryos (from 13 to 18 days old) has been studied. Using optimal excitation (green light, 545 nm), HE- or MT-stained sections showed a selective red emission of the acidophilic tissue components, which was due to eosin Y in the case of HE and to acid fuchsin and/or xylidine ponceau in the case of MT. The fluorescence intensity induced by these anionic dyes was variable and related to the substrate nature and the embryo age. Whereas in young embryos only the immature red blood cells showed a noticeable fluorescence, in the oldest embryos there were also other tissue components that selectively fluoresced with these dyes, in particular fibre lens cells, elastic fibres, zymogen granules and muscle cells. Spectrofluorometric studies on free dyes and densitometric analysis of protein blots confirmed microscopical observations. Our results indicate that the standard HE and MT staining methods can be used in recognizing the appearance of specific protein structures in embryonic tissues by means of fluorescence microscopy.


Assuntos
Embrião de Mamíferos/citologia , Histocitoquímica/métodos , Microscopia de Fluorescência/métodos , Animais , Compostos Azo/metabolismo , Amarelo de Eosina-(YS)/metabolismo , Eritrócitos/citologia , Olho/citologia , Hematoxilina/metabolismo , Pulmão/citologia , Verde de Metila/metabolismo , Microtomia , Miocárdio/citologia , Proteínas/análise , Ratos , Ratos Wistar , Espectrometria de Fluorescência
12.
J Cell Sci ; 110 ( Pt 6): 771-80, 1997 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9099951

RESUMO

Rat basophilic leukemia cells will adhere to and spread out on fibronectin coated surfaces in an integrin dependent manner. Adhesion and spreading on fibronectin leads to increased degranulation, inositol phosphate production, phospholipase D activation, and increased production of prostaglandin D2 and leukotriene C4 when the cells are activated through the high affinity IgE receptor. Rat basophilic leukemia cells will also adhere to surfaces coated with anti-rat class I antibodies, poly-L-lysine, and a lectin purified from Tetragonolobus purpureas. In all cases, antigen activated cells, which were adherent, displayed increased signaling, degranulation and eicosanoid production as compared to cells which were non-adherent. Cells which adhere to either anti-rat class I antibodies or poly-L-lysine also spread even though this is not mediated through integrins. In contrast, adhesion to the lectin from Tetragonolobus did not cause any appreciable spreading unless the cells were also triggered through the IgE receptor. Cells were also able to bind to fibronectin immobilized on polystyrene beads which mimics adhesion but does not allow spreading. However, these cells exhibited no increased signaling, degranulation, or eicosanoid production. Furthermore, rat basophilic leukemia cells can be modified by incubating them in the presence of biotinylated-phosphatidylserine which becomes incorporated into the membrane. These modified cells will adhere to streptavidin coated plates while unmodified cells will not. However, these modified cells do not spread, even after activation with antigen, and they show no increased degranulation or production of eicosanoids. These results indicate that adhesion itself is not sufficient for upregulation of the cells in response to antigen and that spreading of the cells may be the critical component.


Assuntos
Degranulação Celular , Leucemia Basofílica Aguda/fisiopatologia , Fosfolipase D/metabolismo , Fosfolipases A/metabolismo , Receptores de IgE/metabolismo , Fosfolipases Tipo C/metabolismo , Animais , Adesão Celular , Movimento Celular , Ativação Enzimática , Leucemia Basofílica Aguda/enzimologia , Leucemia Basofílica Aguda/patologia , Mastócitos/fisiologia , Fosfolipases A2 , Ratos , Células Tumorais Cultivadas
13.
Am J Clin Nutr ; 64(5): 726-30, 1996 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-8901792

RESUMO

Suggestions that carotenoid-containing foods are beneficial in maintaining health have led to several studies of circulating carotenoid concentrations of adults. Because few data are available for children, we report serum carotenoid concentrations of 493 children in Belize. Carotenoid concentrations were determined as part of a survey of vitamin A status of children, most between 65 and 89 mo of age. Reproducibility was tested by collecting a second blood sample 2 wk after the first collection from a subset of children (n = 23) who consumed their habitual diet with no treatment during the interim. Predominant serum carotenoids were lutein/zeaxanthin and beta-carotene, which accounted for 26% and 24% of median total carotenoids, respectively. The three provitamin A carotenoids, alpha- and beta-carotene and beta-cryptoxanthin, constituted 51% of median total carotenoid concentrations. Partial correlations of each carotenoid with fasting retinol concentration indicated that beta-carotene had the highest correlation. Concordance correlation coefficients (rc) for fasting carotenoid concentrations determined 2 wk apart were > or = 0.89 for lycopene, beta-cryptoxanthin, and alpha- and beta-carotene. The rc for lutein/zeaxanthin and total carotenoids was lower, 0.59 and 0.68, respectively, because of higher lutein/zeaxanthin concentrations at the second sampling than at the first. The reproducibility of the concentrations suggests both that individuals have characteristic profiles and that serum carotenoid concentrations can be measured randomly over > or = 2 wk without significant bias.


Assuntos
Carotenoides/sangue , Belize/epidemiologia , Criança , Pré-Escolar , Cromatografia Líquida de Alta Pressão , Criptoxantinas , Dieta/normas , Humanos , Luteína/sangue , Licopeno , Reprodutibilidade dos Testes , Vitamina A/sangue , Vitamina A/uso terapêutico , Deficiência de Vitamina A/sangue , Deficiência de Vitamina A/tratamento farmacológico , Deficiência de Vitamina A/epidemiologia , Xantofilas , beta Caroteno/análogos & derivados , beta Caroteno/sangue
14.
Am J Clin Nutr ; 64(5): 726-30, Nov. 1996.
Artigo em Inglês | MedCarib | ID: med-2489

RESUMO

Suggestions that carotenoid-containing foods are beneficial in maintaining health have led to several studies of circulating carotenoid concentrations of adults. Because few data are available for children, we report serum carotenoid concentrations of 493 children in Belize. Carotenoid concentrations were determined as part of a survey of vitamin A status of children, most between 65 and 89 mo of age. Reproducibility was tested by collecting a second blood samples 2 wk after the first collection from a subset of children (n = 23) who consumed their habiitual diet with no treatment during the interim. Predominant serum carotenoids were lutein/zeaxanthin and beta-carotene, which accounted for 26 percent and 24 percent of median total carotenoids, respectively. The three provitamin A carotenoids, alpha- and beta-carotene and beta-cryptoaxnthin, constituted 51 percent od median total carotenoid concentrations. Partial correlations of each carotenoid with fasting retinol concentrations indicated that beta-carotene had the highest correlation. Concordance correlation coefficients (rc) for fasting carotenoid concentrati9ons determined 2 wk apart were > or = 0.89 for lycopene, beta-cryptoxanthin, and alpha- and beta-catotene. The rc for lutein/zeaxanthin and total carotenoids was lower, 0.59 and 0.68, respectively, because of higher lutein/zeaxanthin concentrations at the second sampling than at the first. The reproducibility of the concentrations suggest both that individuals have characteristic profiles and that serum carotenoid concentrations can be measured randomly over > or =2 wk without significant bias. (au)


Assuntos
Criança , Pré-Escolar , Humanos , Carotenoides/sangue , Carotenoides/sangue , Carotenoides/sangue , Cromatografia Líquida de Alta Pressão , Dieta/normas , Vitamina A/sangue , Vitamina A/uso terapêutico , Deficiência de Vitamina A/sangue , Deficiência de Vitamina A/tratamento farmacológico , Deficiência de Vitamina A/epidemiologia , Luteína/sangue
15.
J Am Coll Nutr ; 15(5): 439-49, 1996 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8892169

RESUMO

OBJECTIVE: A study of children (2-8 years; n = 613) in Belize, Central America, was conducted to determine what proportion of the children might be at risk of vitamin A (vit A) deficiency. The data provide an opportunity to compare results of three methods of assessing vit A status in a population which was not severely malnourished. Serum retinyl ester concentrations were also determined; their relevance to one of the tests, the relative dose response (RDR) test, is discussed. METHODS: The three methods of assessing vit A status were: RDR test, fasting serum retinol concentration, and conjunctival impression cytology (CIC). Retinol-binding protein (RBP), serum retinyl esters and serum zinc concentrations were also determined. RESULTS: Inadequate vit A status was indicated for 17% of subjects by the RDR test (14% cutoff), for 24% by fasting serum retinol concentration (< 0.87 mumol/L), and for 49% by "abnormal" CIC score. Retinyl esters constituted 24% of serum retinoids at the time (5 hours after a retinyl palmitate dose) at which the second blood sample is taken for the RDR test. Regression tree analyses (CART) indicated ethnicity was a predictor of RDR score; ethnicity, stunting and age were predictors of fasting serum retinol concentration; ethnicity and stunting were predictors of 0-hour retinyl ester concentration. CONCLUSION: The three indices of vit A status did not identify the same individuals nor indicate the same percentage of the population to be at risk for vit A deficiency. Increased concentrations of retinyl esters at 5 hours compared to those at 0 hours suggest that insufficient retinol may have been taken up by the liver at 5 hours to release all accumulated retinol-binding protein (RBP) in deficient individuals; prevalence of vit A deficiency might therefore be underestimated by the RDR test. The selection of ethnicity as a predictor of RDR score and of 0-hour retinol and retinyl ester concentrations suggests that factors other than vit A status affect vit A metabolism and may affect the RDR test.


Assuntos
Estado Nutricional , Vitamina A/sangue , Belize , Criança , Pré-Escolar , Cromatografia Líquida de Alta Pressão , Etnicidade , Feminino , Humanos , Masculino , Fatores de Risco , Zinco/sangue
16.
J Am Coll Nutr ; 15(5): 450-7, 1996 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8892170

RESUMO

OBJECTIVE: Reproducibility of the relative dose response test (RDR), a test designed to measure vitamin A status, was tested in 23 Belizean children, 5-8 years after 2-week interval during which no treatment was given. METHODS: As required for the RDR test, serum retinol concentrations were determined before and 5 hours after an oral dose of vitamin A. An RDR score > 14% was used as the criterion of inadequate vitamin A status. The HPLC method used to measure serum retinol concentrations also determined the concentrations of four retinyl esters. RESULTS: The RDR test was reproducible for 17 of 23 subjects: 3 scored > 14% on both tests; 14, < 14% on both. Six subjects scored > 14% on only one test. The concordance correlation coefficient (rc) for the percent change in the two tests was 0.24; for fasting serum retinol concentration, rc = 0.81. For retinyl palmitate and stearate, the esters present in highest concentrations at 5 hours, concordance correlation coefficients were 0.75 and 0.59, respectively. CONCLUSION: The failure of the RDR test to classify 26% of the subjects reproducibly reduces the usefulness of the test. In addition, the reproducibility of the retinyl ester concentrations in serum 5 hours after the retinyl palmitate dose and the relatively high concentrations in some subjects suggests that some individuals may not metabolize sufficient retinol in 5 hours to cause a maximal increase in serum retinol, resulting in an underestimation of deficiency in a population in which the RDR test is used.


Assuntos
Anticarcinógenos/sangue , Vitamina A/análogos & derivados , Vitamina A/sangue , Criança , Pré-Escolar , Cromatografia Líquida de Alta Pressão , Diterpenos , Relação Dose-Resposta a Droga , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes , Ésteres de Retinil , Vitamina A/administração & dosagem
17.
J Am Coll Nutr ; 15(5): 439-49, Oct. 1996.
Artigo em Inglês | MedCarib | ID: med-2095

RESUMO

A study of children (2 - 8 years; n = 613) in Belize, Central America, was conducted to determine what proportion of the children might be at risk of vitamin A (vit A) deficiency. The data provide an opportunity to compare results of three methods of assessing vit A status in a population which was not severely malnourished. Serum retinyl ester concentrations were also determined; their relevance to one of the tests, the relative dose response (RDR) test, is discussed. METHODS: The three methods of assessing vit A status were: RDR test, fasting serum rintol concentration, and conjunctival impression cytology (CIC). Retinol-binding protein (RBP), serum retinyl esters and serum zinc concentrations were also determined. RESULTS: Inadequate vit A status was indicated for 17 percent of subjects by the RDR test (14 percent cutoff), for 24 percent by fasting serum retinol concentration (< 0.87 mumol/L), and for 49 prcent by abnormal. CIC score. Retinyl esters constituted 24 percent of serum retinoids at the time (5 hours after a retinyl palmitate dose) at which the second blood sample is taken for the RDR test. Regresssion trees analyses (CART) indicated ethnicity was a predictor of RDR score; ethnicity, stunting and age were predictors of fasting serum retinol concentration; ethnicity and stunting were predictors of O-hour retinyl ester concentration. CONCLUSION: The three indices of vit A status did not identify the same individuals nor indicate the same percentage of the population to be at risk for hours compared to those at O hours suggest that insufficient retinol may have been taken up by the liver at 5 hours to release all accumulated retinol-binding protein (RBP) in deficient individuals; prevalence of vit A deficiency might therefore be underestimated by the RDR test. The selection of ethnicity as a predictor of RDR score and of O-hour retinol and retinyl ester concentrations suggests that factors other than vit A status affect vit A metabolism and may affect the RDR test.(AU)


Assuntos
Estudo Comparativo , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Estado Nutricional , Vitamina A/sangue , Belize , Cromatografia Líquida de Alta Pressão , Etnicidade , Fatores de Risco , Zinco/sangue
19.
Mol Biol Cell ; 6(1): 97-108, 1995 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-7749199

RESUMO

Cross-linking of the immunoglobulin E receptor on rat basophilic leukemia (RBL)1 cells by multivalent antigen activates phosphatidylinositol (PI) kinase and phosphatidylinositol 4-phosphate (PIP) kinase leading to the increased production of PIP and phosphatidylinositol 4,5-bisphosphate (PIP2). Activators of protein kinase C (PKC), such as phorbol myristate acetate (PMA) and the synthetic diacylglycerol, 1,2-dioctanoyl-sn-glycerol (diC8), were found to have the same effect even though PMA and diC8 do not cause the activation of phospholipase C. Although the kinetics are different depending on the stimulant, activation of PKC using multivalent antigen, PMA or diC8 also causes the polymerization of actin and an increase in the F-actin content of the cells. In all cases, a good correlation was observed between F-actin levels, activation of PI and PIP kinases, and the increased production of PIP and PIP2. However, in the case of antigen, there is no correlation between actin polymerization and the total amount of PIP and PIP2. Staurosporine, an inhibitor of protein kinases, blocks the F-actin response and the increased synthesis of PIP and PIP2 with similar dose dependencies. Furthermore, depletion of PKC activity through long-term exposure to PMA, inhibited both the F-actin response and the increased synthesis of PIP and PIP2 induced by either DNP-BSA or diC8. These results suggest that activation of PKC precedes the activation of PI and PIP kinases and that under certain circumstances activation of the kinases and the increased synthesis of PIP and PIP2 may be involved in the polymerization of actin in RBL cells, possibly through the interaction of the polyphosphoinositides with actin-binding proteins such as gelsolin and profilin.


Assuntos
Actinas/metabolismo , Leucemia Basofílica Aguda/enzimologia , Proteínas de Neoplasias/fisiologia , Fosfatos de Fosfatidilinositol/metabolismo , Proteína Quinase C/fisiologia , Receptores de IgE/metabolismo , Transdução de Sinais , Alcaloides/farmacologia , Animais , Biopolímeros , Diglicerídeos/farmacologia , Dinitrofenóis/imunologia , Ativação Enzimática , Capeamento Imunológico , Fosfatidilinositol 4,5-Difosfato , Proteína Quinase C/antagonistas & inibidores , Ratos , Soroalbumina Bovina/imunologia , Estaurosporina , Acetato de Tetradecanoilforbol/farmacologia , Células Tumorais Cultivadas
20.
Am J Clin Nutr ; 60(6 Suppl): 1060S-1064S, 1994 12.
Artigo em Inglês | MEDLINE | ID: mdl-7977152

RESUMO

Although consumed in some form since at least 460 AD, cacao (Theobroma cacao) was not used in confectionery until the 19th century when the cocoa press was invented. Per capita consumption of chocolate confectionery in the United States is moderate (approximately 4.6-4.8 kg/y) compared with that of many northern European countries (approximately 7-10 kg/y). Eleven percent of the US population reported consuming chocolate candy on > or = 1 of the 3 d of recorded food intake in the US Department of Agriculture Nationwide Food Consumption Survey 1987-1988; < 1.0% consumed chocolate every day. The Western region of the United States contained the highest proportion of chocolate consumers. More whites than other racial groups were consumers. Chocolate was consumed by more people in the winter than in other seasons and more was consumed at snacks than at meals. The mean amount of chocolate consumed was approximately 30-90 g/d, depending on sex and age group. Chocolate candy was only a minor contributor (0.7-3.4%) to the overall dietary intake of total energy, fat, saturated fatty acids, and stearic acid.


Assuntos
Cacau , Doces , Gorduras na Dieta/administração & dosagem , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Estados Unidos
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