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1.
Lipids ; 36(5): 473-5, 2001 May.
Artículo en Inglés | MEDLINE | ID: mdl-11432459

RESUMEN

In this study the effect of luminal lipid on the absorption of canthaxanthin (CTX) was investigated using the lymph duct cannulated rat. Treatments were emulsions designed to deliver increasing amounts of olive oil (10, 30, 50, 70, or 90 mg/h) and CTX (12.5 nmol/h). Emulsions were continuously infused into the duodenum for 12 h, and lymph was collected during the final 6 h of infusion for analysis. As the amount of lipid in the emulsion increased, a linear increase in the absorption of CTX was observed. The recovery of CTX in the lymph when infused with 10 mg/h olive oil was 14.2 +/- 1.2% and with 90 mg/h was 26.9 +/- 5.7%. The efficiency of CTX absorption nearly doubled by increasing the amount of lipid infused with CTX. The correlation between lipid load and CTX absorbed was r= 0.85. We conclude that luminal lipid load affects CTX absorption.


Asunto(s)
Cantaxantina/metabolismo , Absorción Intestinal , Mucosa Intestinal/metabolismo , Metabolismo de los Lípidos , Animales , Cantaxantina/administración & dosificación , Cantaxantina/análisis , Cantaxantina/farmacocinética , Cromatografía de Gases , Cromatografía Líquida de Alta Presión , Absorción Intestinal/efectos de los fármacos , Intestinos/efectos de los fármacos , Linfa/química , Masculino , Aceite de Oliva , Aceites de Plantas/farmacología , Ratas
2.
Lipids ; 35(7): 803-6, 2000 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10941883

RESUMEN

The effect of different oils on the absorption of carotenoids was investigated in mesenteric lymph duct cannulated rats. Sixteen treatment emulsions containing increasing concentrations of either lycopene (LYC) or astaxanthin (AST) (5, 10, 15, 20 micromol/L) were prepared with olive oil or corn oil and continuously infused into the duodenum of the rat. Absorption of carotenoids into the mesenteric lymph duct was determined. Absorption of LYC and AST from both oils increased with the amount infused into the duodenum. The average recovery of AST in the lymph from the olive oil emulsion was 20% but was decreased to 13% from emulsions containing corn oil. Lycopene was not as well absorbed as AST. The average recovery of LYC was 6% from olive oil emulsions but only 2.5% when infused with corn oil. The LYC used in this study was isolated from tomato paste and was primarily in the all-trans form. We did not observe any significant isomerization of all-trans LYC to 9-cis LYC during absorption. We conclude that the type of oil with which a carotenoid is consumed can influence its absorption.


Asunto(s)
Carotenoides/farmacocinética , Aceite de Maíz , Grasas de la Dieta , Absorción Intestinal , Aceites de Plantas , beta Caroteno/análogos & derivados , Animales , Carotenoides/administración & dosificación , Aceite de Maíz/administración & dosificación , Duodeno , Emulsiones , Infusiones Parenterales , Licopeno , Linfa/fisiología , Masculino , Aceite de Oliva , Aceites de Plantas/administración & dosificación , Ratas , Ratas Sprague-Dawley , Xantófilas , beta Caroteno/farmacocinética
3.
Am J Clin Nutr ; 71(3): 789-94, 2000 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-10702174

RESUMEN

BACKGROUND: The coexistence of multiple micronutrient deficiencies is a widespread public health problem in many regions of the world. Interactions between zinc deficiency and vitamin A metabolism have been reported but no longitudinal studies have evaluated the effect of iron deficiency on vitamin A. OBJECTIVE: The objective of this study was to investigate the effect of supplementation with iron, zinc, or both on vitamin A and its metabolically related proteins retinol binding protein (RBP) and transthyretin. DESIGN: The study was a longitudinal, double-blind, placebo-controlled trial in which 219 rural Mexican children aged 18-36 mo were randomly assigned to receive 20 mg Zn/d, 20 mg Fe/d, 20 mg Zn/d plus 20 mg Fe/d, or placebo. RESULTS: Six months after supplementation, plasma retinol increased in all supplemented groups. Compared with placebo, zinc supplementation was associated with significantly higher plasma retinol and transthyretin but the increase in RBP was not significant. Iron supplementation significantly increased plasma retinol, RBP, and transthyretin. Supplementation with zinc plus iron significantly increased plasma retinol but not RBP or transthyretin. Children deficient in zinc, iron, or vitamin A (as indicated by nutrient plasma concentration) at the beginning of the study had a significantly greater increase in retinol than did children with adequate nutrient status. CONCLUSIONS: Supplementation with zinc, iron, or both improved indicators of vitamin A status. The results of this study agree with previous observations of a metabolic interaction between zinc and vitamin A and suggest an interaction between iron and vitamin A metabolism.


Asunto(s)
Suplementos Dietéticos , Hierro de la Dieta/administración & dosificación , Estado Nutricional , Vitamina A/sangre , Zinc/administración & dosificación , Preescolar , Método Doble Ciego , Ferritinas/sangre , Hemoglobinas/análisis , Humanos , Lactante , Hierro/sangre , Deficiencias de Hierro , Estudios Longitudinales , México , Placebos , Prealbúmina/análisis , Zinc/sangre , Zinc/deficiencia
4.
Lipids ; 34(6): 627-31, 1999 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-10405977

RESUMEN

The recent attention given to the possible role of alpha-tocopherol (alpha-Toc) and carotenoids in the prevention and treatment of a variety of illnesses resulted in segments of the population increasing their consumption of these nutrient/antioxidants. Once consumed, alpha-Toc and carotenoids are thought to follow the same absorptive pathway and may influence each other's absorption, particularly when taken in large doses. The purpose of this study was to determine if alpha-Toc and the carotenoid, canthaxanthin (CTX), interact during absorption. Rats were intraduodenally infused with corn oil emulsions containing combinations of alpha-Toc (0 or 300 mumol/L) and CTX (5, 10, 15, 20 mumol/L) in a 2 x 4 factorial arrangement. Absorption was determined by measuring recovery of CTX and alpha-Toc in the mesenteric lymph. The amount of CTX in the lymph increased significantly with the amount infused into the duodenum. The overall efficiency of CTX absorption from emulsions without alpha-Toc averaged 12% with individual animals having a range of 8 to 18%. Efficiency of absorption was not related to concentration of CTX infused. When alpha-Toc (300 mumol/L) was added to the oil emulsion, the absorption of CTX was decreased by at least 50%. Recovery of alpha-Toc in the lymph averaged ca. 10% and was not affected by CTX. These results suggest that concurrent consumption of a large dose of alpha-Toc may influence carotenoid bioavailability.


Asunto(s)
Cantaxantina/metabolismo , Vitamina E/administración & dosificación , Animales , Cantaxantina/antagonistas & inhibidores , Linfa/metabolismo , Masculino , Ratas , Vitamina E/farmacología
5.
Mol Biotechnol ; 10(2): 167-82, 1998 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-9819815

RESUMEN

Retinoids are unstable compounds being readily oxidized and/or isomerized to altered compounds, especially in the presence of oxidants including air, light, and excessive heat. They are labile toward strong acids and solvents that have dissolved oxygen or peroxides. In this review, procedures for handling and storage of retinoids and biological samples containing them have been described. The physical and chemical properties of retinoids have been reported. Simplified procedures for derivatizations and purification, and methods for quantitation of retinoids have been presented.


Asunto(s)
Retinoides/análisis , Retinoides/química , Cromatografía , Solubilidad , Espectrofotometría
6.
J Nutr ; 128(10): 1703-9, 1998 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-9772139

RESUMEN

The effect of the fatty acid composition of reduced-fat diets on the in vitro oxidation of LDL was examined in 14 moderately hypercholesterolemic [low density lipoprotein (LDL) > 3.36 mmol/L] postmenopausal female and male subjects (age 44-78 y). Each subject consumed each of five reduced-fat diets [30 energy percent (E%) fat, 17 E% protein and 53 E% carbohydrate] enriched in beef tallow, canola oil, corn oil, olive oil or rice bran oil (20 E%) for 32-d periods. In vitro oxidation of LDL was assessed by incubating LDL with hemin and hydrogen peroxide, and measuring the time required for the reaction to reach maximum velocity (lag time). LDL lag times were 93.2 +/- 25.8, 95.9 +/- 26.4, 104.2 +/- 32.7, 108.0 +/- 26.6 and 113.1 +/- 24.0 min for corn oil, beef tallow, rice bran oil, canola oil and olive oil periods, respectively. When the data from all dietary phases were pooled, LDL alpha-tocopherol level (r = 0.30, P = 0.01) and plasma 18:1/18:2 ratio (r = 0.22, P = 0.08) were positively related to resistance of LDL to oxidation. Differences induced by the dietary perturbations in LDL content of beta-cryptoxanthin, lutein/zeaxanthin, lycopene, alpha-carotene or beta-carotene, and LDL particle size were not related to resistance of LDL to oxidation. In conclusion, in middle-aged and elderly moderately hypercholesterolemic subjects, the consumption of reduced-fat diets enriched in animal fat or vegetable oils with a relatively wide range of fatty acid profiles did not alter the in vitro susceptibility of LDL to oxidation. The advantages of reducing the saturated fat content of the diet were reflected in lower total and LDL cholesterol levels.


Asunto(s)
LDL-Colesterol/metabolismo , Dieta con Restricción de Grasas , Grasas de la Dieta/farmacología , Hipercolesterolemia/metabolismo , Adulto , Anciano , LDL-Colesterol/sangre , Grasas de la Dieta/administración & dosificación , Femenino , Humanos , Masculino , Persona de Mediana Edad , Oxidación-Reducción , Tamaño de la Partícula
8.
Lipids ; 33(2): 159-63, 1998 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-9507237

RESUMEN

The purpose of this study was to validate the use of the mesenteric lymph duct cannulated rat to study the absorption of carotenoids which do not have provitamin A activity. The absorption of two carotenoids, a hydrocarbon carotenoid (lycopene) and a xanthophyll carotenoid (canthaxanthin), were investigated. In the first experiment, lipid emulsions containing lycopene (LYC) or canthaxanthin (CTX) were continuously infused into the duodenum, and lymph was collected for analysis at 2-h intervals. The time course for absorption of carotenoids and triacylglycerol (TAG) was similar. Carotenoids and TAG reached steady-state concentrations in the lymph by 6 h. There was no evidence for a delayed release of either carotenoid from the intestine relative to TAG. During a second experiment, emulsions containing increasing concentrations of LYC or CTX (5, 10, 15, 20 mumol/L) were infused. The LYC and CTX in the lymph increased in a dose-dependent manner. The average efficiency of CTX absorption was 16% while the efficiency of LYC absorption averaged only 6%. Efficiency of carotenoid absorption was not related to concentration infused. Finally, to test whether LYC and CTX interact during absorption both were added to a lipid emulsion at equal concentrations (20 mumol/L) and infused. The carotenoids did not significantly affect each other's absorption. These results demonstrate the usefulness of the rat as an animal model to study the absorption of non-provitamin A carotenoids.


Asunto(s)
Cantaxantina/metabolismo , Carotenoides/metabolismo , Absorción Intestinal , Animales , Transporte Biológico , Interacciones Farmacológicas , Licopeno , Linfa/química , Masculino , Ratas , Triglicéridos/metabolismo
10.
Biometrics ; 51(1): 12-20, 1995 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-7766769

RESUMEN

A kernel-smoothing method with locally varying bandwidths for the nonparametric estimation of derivatives of a function is proposed for highly nonequidistant data as they occur in pharmacokinetic response curves. We construct estimates having the particular property that the derivative estimates correspond exactly to the corresponding derivatives of the curve estimate even under locally varying bandwidth choice. The effects on the estimation of peak location (characteristic points) are investigated. In an example, characteristic points are estimated for a recently developed in vivo isotope dilution assay for vitamin A (retinol) nutritional status. The in vivo kinetics of appearance and disappearance of isotopically labeled retinol can be described with the proposed method.


Asunto(s)
Anticarcinógenos/farmacocinética , Biometría/métodos , Modelos Estadísticos , Farmacocinética , Vitamina A/farmacocinética , Humanos , Matemática
11.
J Chromatogr ; 616(1): 31-7, 1993 Jun 23.
Artículo en Inglés | MEDLINE | ID: mdl-8376490

RESUMEN

In this paper, we present a fast minimicroassay of serum vitamin A by capillary zone electrophoresis with laser-excited fluorescence detection. A 60 cm x 50 microns I.D. fused-silica capillary was used for the separation, and the polymer coating was burned off 20 cm from the cathodic end to form a detection window. The buffer system consisted of 50 mM sodium phosphate plus 10 mM sodium chloride at pH 7.8. A helium-cadmium laser set at 325 nm was used for excitation, and the fluorescence of the vitamin A-retinol-binding protein complex was monitored at 465 nm using a photodiode. The stray and scattered radiation were removed by two special filters. Using this system, about 8 nl of serum sample were injected for direct analysis without any sample preparation. The analysis time for each sample was less than 6 min, and subfemtomole levels of vitamin A in human or animal blood could be easily detected. Therefore, the method is potentially useful for finger-prick vitamin A analysis, especially for babies and young children.


Asunto(s)
Vitamina A/sangre , Tampones (Química) , Electroforesis , Humanos , Concentración de Iones de Hidrógeno , Indicadores y Reactivos , Rayos Láser , Espectrometría de Fluorescencia
13.
Biochem Cell Biol ; 70(9): 809-13, 1992 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-1482558

RESUMEN

The fatty-acid composition of retinyl esters in the livers of two species of phocid seal, the harp seal (Phoca groenlandica, n = 20) and the hooded seal (Cystophora cristata, n = 15), and one species of otariid seal, the California sea lion (Zalophus californianus, n = 6), was determined. Vitamin A ranged in concentration from 4 to 1024 nmol retinol/g liver for the phocids and from 381 to 979 nmol/g liver for the otariids. In most of the livers, retinyl palmitate was not the principal ester, and the palmitate + stearate + oleate trio of retinyl esters represented less than 50% of the total. In all samples, the retinyl esters contained 20:1, 20:4, 20:5, and 22:6 in unusually large amounts. Retinyl esters tended to be richer than whole-liver lipids in 20:5 + 22:6, whereas whole-liver lipids were richer in 18:0 and 18:2. Therefore, the pool of acyl donors used for the esterification of retinol may be distinct from that used for other lipids. Birth-to-weaning changes were seen only in the harp seals. In the pups, the hepatic vitamin-A concentration increased 454%, while the proportion of 18:0 and 20:1 in the retinyl esters rose and that of 14:0 + 16:1 and 20:4 fell. Concomitantly, in their mothers, the proportion of 20:4 increased but that of 16:0 and 18:0 decreased.


Asunto(s)
Ácidos Grasos/análisis , Hígado/química , Leones Marinos/metabolismo , Vitamina A/química , Animales , Ésteres , Especificidad de la Especie
14.
Am J Clin Nutr ; 56(2): 433-9, 1992 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-1636622

RESUMEN

Single oral doses (100 mumol) in peanut oil of 4,4'-dimethoxy-beta-carotene, ethyl beta-apo-8'-carotenoate, and beta-apo-8'-carotenal were administered to healthy adult male subjects (n = 4-6). Blood samples were taken frequently thereafter, and serum carotenoids and retinoids were analyzed by HPLC. The metabolism of the three analogs was very different; 4,4'-dimethoxy-beta-carotene was oxidized at the 4 and 4' positions but apparently not cleaved, whereas ethyl beta-apo-8'-carotenoate was not detectably metabolized, and beta-apo-8'-carotenal was extensively converted to its corresponding acid, alcohol, and fatty acyl ester and detectably converted to retinyl ester and possibly to two shorter beta-apocarotenals. Serum concentrations of endogenous retinoids and carotenoids, except as noted above, were not affected in any case. Kinetically, the maximum serum concentrations, areas under the curve, and mean sojourn times for the three analogs differed by 50-, 270-, and 5-fold, respectively. For any given analog, however, the fractional standard deviations for these parameters were only 0.2-0.5.


Asunto(s)
Carotenoides/farmacocinética , Administración Oral , Adulto , Transporte Biológico , Carotenoides/administración & dosificación , Carotenoides/química , Humanos , Absorción Intestinal , Masculino
17.
Brain Res Bull ; 26(2): 235-9, 1991 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-2012983

RESUMEN

The retinoids and carotenoids in bovine pineal gland were analyzed by high-performance liquid chromatographic methods. The major retinoid observed was all-trans retinol, with an average level of 579 pmol/g wet tissue. In agreement with a previous report, retinal was not detected; however, we could not detect any retinyl ester in bovine pineal gland. Methods similar to those used in studying metabolism of vitamin A in the bovine eye were used to study the esterification and isomerization reactions of retinoids in the pineal gland. Neither esterification nor isomerization reactions occurred. These results suggest that the key retinoids and enzymes involved in visual function are absent in the bovine pineal gland. The major carotenoid, which has not previously been reported in pineal gland, was beta-carotene at an average level of 1830 pmol/g wet tissue.


Asunto(s)
Carotenoides/análisis , Glándula Pineal/química , Retinoides/análisis , Animales , Bovinos , Cromatografía Líquida de Alta Presión , Isomerismo
19.
Eur J Clin Nutr ; 44(3): 219-24, 1990 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-2369888

RESUMEN

After an appropriate dose of 3,4-didehydroretinol (vitamin A2, DR) is given orally in corn oil to retinol (R)-depleted rats, the ratio of plasma DR/R values at 3.5 h is inversely related to the liver concentration of vitamin A (Tanumihardjo & Olson, 1988). In the present study, a similar procedure, termed the modified relative dose response (MRDR) assay, was employed with rats containing a much broader range of liver reserves; ie, less than 2 to 107 nmol of vitamin A per g wet weight of liver (less than 1 to 30 micrograms/g). The DR/R ratio for 15 of 16 rats with liver reserves less than 17 nmol/g (less than 5 micrograms/g) was greater than 0.15, whereas the ratio was less than 0.15 for 7 of 8 rats with liver reserves greater than 17 nmol/g. This distribution provides sensitivity, specificity and positive predictive values of 94, 88 and 94 per cent, respectively. The DR/R ratios reached a maximal plateau in two other groups of rats between 3.5 and 8 h. At all times up to 24 h, mean DR/R ratios for vitamin A-depleted rats (45 +/- 6 nmoles of vitamin A/g liver) were approximately twice those for vitamin A-sufficient rats (230 +/- 40 nmoles of vitamin A/g liver). In three well-nourished adults, presumably with liver reserves of greater than 300 nmol/g wet weight liver (greater than 80 micrograms retinol equivalents/g), and in two young (1- and 3-years old) well-nourished children, maximal DR/R ratios were less than 0.023. In these cases, peak DR/R ratios were observed, with one possible exception, between 8 and 12 h.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Hígado/análisis , Deficiencia de Vitamina A/diagnóstico , Vitamina A/sangre , Administración Oral , Animales , Cromatografía Líquida de Alta Presión , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Masculino , Ratas , Ratas Endogámicas , Vitamina A/administración & dosificación , Deficiencia de Vitamina A/sangre
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