ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
A technique is described for the analysis by gradient-elution reverse-phase high-pressure liquid ... more A technique is described for the analysis by gradient-elution reverse-phase high-pressure liquid chromatography of vitamin A at 325 nm in small liver samples taken by needle biopsy. This assay, in contrast to previous procedures, allows rapid separation and quantitation of approximately 0.1 microgram retinol and retinyl esters, requires only 7 mg liver sample, and separates groups of retinyl esters. Vitamin A values determined in needle biopsy samples (7 to 70 mg) and in gross samples (1 to 6.3 g) of the same 24 autopsy specimens correlated well (R = 0.96) over the range 1 to 400 micrograms vitamin A per g liver. The ratio of total vitamin A values in micro- and macrosamples was 1.09 +/- 0.46 (SD). Total vitamin A values in macrosamples of liver determined by high-pressure liquid chromatography and by a differential spectrophotometric assay also correlated well (R = 0.91). Under suitable clinical conditions, the procedure should be useful in validating indirect techniques for assess...
(11,12-³H) all-trans Retinol and various detergents were added to homogenates of fresh bovine re... more (11,12-³H) all-trans Retinol and various detergents were added to homogenates of fresh bovine retinal pigment epithelium. After dark incubation for 40 minutes at 37°C, the retinoids were extracted and analyzed by a high resolution HPLC method. The detergents showed different effects on the retinyl ester synthetase (RES) and all-trans:11 cis retinoid isomerase (RI) activities. The detergent CHAPS (0.3%) almost totally destroyed RI activity without reducing RES activity. The same concentration of sodium dodecyl sulfate and Nonidet P-40 significantly reduced RES activity and totally destroyed RI activity. RES and RI activities were unaffected by 0.3% Mega 8, a nonionic detergent, but were inhibited by 1% Mega 8. Thus, because of these differential effects of detergents, RES and RI probably are different enzymes rather than a single multifunctional enzyme. Because isomerization was always inhibited more than esterification, our findings also accord with the esterification/isomerizatio...
Vitamin A deficiency is a major global public health problem. Among the variety of techniques tha... more Vitamin A deficiency is a major global public health problem. Among the variety of techniques that are available for assessing human vitamin A status, evaluating the provitamin A nutritional values of foodstuffs and estimating human vitamin A requirements, isotope dilution provides the most accurate estimates. Although the relative expense of isotope dilution restricts its applications, it has an important function as the standard of reference for other techniques. Mathematical modelling plays an indispensable role in the interpretation of isotope dilution data. This review summarises recent applications of stable isotope methodology to determine human vitamin A status, estimate human vitamin A requirements, and calculate the bioconversion and bioefficacy of food carotenoids.
... met Giovanna del Nero. Despite the misgivings of Professor Chain, who warned her that America... more ... met Giovanna del Nero. Despite the misgivings of Professor Chain, who warned her that Americans have terrible food, Giovanna agreed to tutor Olson in Italian. They subsequently married and had three children: Daniel (an attorney), Lisa (a biochemist), and Eric (a veterinarian ...
International journal for vitamin and nutrition research. Internationale Zeitschrift für Vitamin- und Ernährungsforschung. Journal international de vitaminologie et de nutrition, 1990
Surgical liver biopsy samples from seven diseased and five healthy human subjects, 3-33 years of ... more Surgical liver biopsy samples from seven diseased and five healthy human subjects, 3-33 years of age, were analyzed by reversed-phase high-pressure liquid chromatography for retinol (vitamin A alcohol), retinyl esters (vitamin A esters), and carotenoids. Total liver vitamin A values ranged from 7.8 to 2860 nmol/g liver (2.2 to 817 micrograms/g). As a percentage, liver retinol decreased with increasing liver reserves of vitamin A. Retinyl palmitate was the predominant vitamin A ester (57 to 83 mole%) in all samples, with retinyl stearate (5.5 to 11.4%), oleate (4.9 to 17.2%), and myristate plus palmitoleate (pair not resolved; 3.3 to 11.9%) next most common. Lesser amounts of retinyl linoleate, linolenate, and arachidonate were found. Normal livers had significant amounts of several carotenoids: lutein (0.2 to 16.2 nmol/g), lycopene (10.2 to 55.1 nmol/g), alpha-carotene (3.0 to 7.3 nmol/g), and beta carotene (5.8 to 25 nmol/g). Total carotenoid values ranged from 26.5 to 67 nmol/g in...
... However, you may be able to access this article under your organization's agreem... more ... However, you may be able to access this article under your organization's agreement with Elsevier. Harold C. Furr, Jason CH Shih, Earl H. Harrison, Hsien-Hsin Chang, Joseph T. Spence,Lemuel D. Wright and Donald B. McCormick. Available online 27 November 2003. Excerpt. ...
In this paper, we present a fast minimicroassay of serum vitamin A by capillary zone electrophore... more 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, espec...
The dependence of liver retinyl ester (vitamin A ester) composition on dietary fatty acid composi... more The dependence of liver retinyl ester (vitamin A ester) composition on dietary fatty acid composition was studied in rats. Weanling male Sprague-Dawley rats were fed purified test diets containing 8% of one of 10 test triglycerides (either tributyrin, tricaproin, tricaprylin, tricaprin, trilaurin, trimyristin, tripalmitin, tristearin, triolein, trilinolein) or corn oil (a mixed triglyceride) for 23 d after an initial 1-wk stabilization period. Essential fatty acids were provided by safflower oil (8 g/kg diet). Total liver fatty acid composition showed the expected responses to dietary fatty acid intake; short-chain and medium-chain fatty acids were readily elongated to palmitate and stearate, and palmitate and stearate were readily desaturated. Consumption of oleate or linoleate (as their triglycerides) markedly enriched their concentrations in liver lipids. The proportions of palmitate were generally greater in liver retinyl esters than in total liver fatty acids, and the proportio...
The vitamin A status in 11 generally healthy surgical patients was estimated by measuring the dil... more The vitamin A status in 11 generally healthy surgical patients was estimated by measuring the dilution of a 45-mg oral dose of tetradeuterated retinyl acetate (99% pure). After purification of retinol by high-performance liquid chromatography, the ratio of 2H4-retinol:1H-retinol in plasma was measured by gas chromatography-mass spectrometry. On the basis of the observed ratios of [2H4]retinol:[1H]retinol over 19-47 d, the total body reserves and liver concentrations of vitamin A were calculated. Liver biopsy samples taken at surgery were directly analyzed for vitamin A. The correlation coefficient between calculated and measured liver vitamin A concentrations for 10 of the subjects was 0.88, and the Spearman's rank correlation coefficient was 0.95 (p less than 0.002). Thus, total body reserves of vitamin A in humans can be estimated validly in the marginal and satisfactory ranges by a benign, relatively noninvasive procedure.
After an appropriate dose of 3,4-didehydroretinol (vitamin A2, DR) is given orally in corn oil to... more 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 ...
Comparative biochemistry and physiology. B, Comparative biochemistry, 1986
Acyl coenzyme A:retinol acyltransferase activity was identified in the microsomes from a polar be... more Acyl coenzyme A:retinol acyltransferase activity was identified in the microsomes from a polar bear liver. The highest rate of in vitro retinol esterification was 821 pmol/min/mg microsomal protein. The in vitro esterification rate displayed a small dependence upon the concentration of exogenous protein (bovine serum albumin) and even less on the concentration of sulfhydryl-reducing agent (dithiothreitol). Vitamin A was present in the liver at a concentration of 8050 micrograms/g tissue, with 98% of the vitamin in its ester form. Retinyl palmitate was 37.3% of the total liver retinyl esters, while retinyl oleate represented 20.9%, stearate 12.8%, and linoleate 7.7%.
Page 19. 1 Vitamin A and Carotenoids Arun B. Barua and James Allen Olson Iowa State University, A... more Page 19. 1 Vitamin A and Carotenoids Arun B. Barua and James Allen Olson Iowa State University, Ames. Iowa Harold C. Furr University of Connecticut. Storrs, Connecticut Richard B. van Breemen University of Illinois at Chicago ...
The sera of adult aquarium-held pinnipeds from four species (family Phocidae: harbor seals (Phoca... more The sera of adult aquarium-held pinnipeds from four species (family Phocidae: harbor seals (Phoca vitulina) and gray seals (Halichoerus grypus); family Otariidae: northern fur seals (Callorhinus ursinus) and California sea lions (Zalophus californianus)) were analyzed for vitamin A (retinol), vitamin E (atocopherol), total cholesterol, triglycerides, phospholipids, and fatty acids. Each subject animal was healthy at the time of blood collection, was fasted for at least 12 hr prior to sampling, and was maintained on a constant diet and supplement regime throughout the study. Retinol values for the four species ranged from 0.16 to 0.92 mg/mL, with the lowest concentrations seen in the harbor seals and the highest in the northern fur seals. Vitamin E values ranged from 10.55 to 43.58 mg/ mL, with northern fur seals showing the highest and gray seals the lowest levels. Vitamin E/lipid ratios (cholesterol, triglyceride, phospholipid, and total lipids) were also examined. A significant correlation was seen between vitamin E and total lipids (Po0.05) and phospholipid (Po0.01). Statistical analysis of the retinol, tocopherol, triglyceride, and phospholipid levels showed significant differences between phocid and otariid seals. Otariids had significantly lower tocopherol and phospholipid values (19.36 mg/mL, 4.29 mg/mL) and the phocids had significantly lower retinol and triglyceride levels (0.29 mg/mL, 124 mg/dL).
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
A technique is described for the analysis by gradient-elution reverse-phase high-pressure liquid ... more A technique is described for the analysis by gradient-elution reverse-phase high-pressure liquid chromatography of vitamin A at 325 nm in small liver samples taken by needle biopsy. This assay, in contrast to previous procedures, allows rapid separation and quantitation of approximately 0.1 microgram retinol and retinyl esters, requires only 7 mg liver sample, and separates groups of retinyl esters. Vitamin A values determined in needle biopsy samples (7 to 70 mg) and in gross samples (1 to 6.3 g) of the same 24 autopsy specimens correlated well (R = 0.96) over the range 1 to 400 micrograms vitamin A per g liver. The ratio of total vitamin A values in micro- and macrosamples was 1.09 +/- 0.46 (SD). Total vitamin A values in macrosamples of liver determined by high-pressure liquid chromatography and by a differential spectrophotometric assay also correlated well (R = 0.91). Under suitable clinical conditions, the procedure should be useful in validating indirect techniques for assess...
(11,12-³H) all-trans Retinol and various detergents were added to homogenates of fresh bovine re... more (11,12-³H) all-trans Retinol and various detergents were added to homogenates of fresh bovine retinal pigment epithelium. After dark incubation for 40 minutes at 37°C, the retinoids were extracted and analyzed by a high resolution HPLC method. The detergents showed different effects on the retinyl ester synthetase (RES) and all-trans:11 cis retinoid isomerase (RI) activities. The detergent CHAPS (0.3%) almost totally destroyed RI activity without reducing RES activity. The same concentration of sodium dodecyl sulfate and Nonidet P-40 significantly reduced RES activity and totally destroyed RI activity. RES and RI activities were unaffected by 0.3% Mega 8, a nonionic detergent, but were inhibited by 1% Mega 8. Thus, because of these differential effects of detergents, RES and RI probably are different enzymes rather than a single multifunctional enzyme. Because isomerization was always inhibited more than esterification, our findings also accord with the esterification/isomerizatio...
Vitamin A deficiency is a major global public health problem. Among the variety of techniques tha... more Vitamin A deficiency is a major global public health problem. Among the variety of techniques that are available for assessing human vitamin A status, evaluating the provitamin A nutritional values of foodstuffs and estimating human vitamin A requirements, isotope dilution provides the most accurate estimates. Although the relative expense of isotope dilution restricts its applications, it has an important function as the standard of reference for other techniques. Mathematical modelling plays an indispensable role in the interpretation of isotope dilution data. This review summarises recent applications of stable isotope methodology to determine human vitamin A status, estimate human vitamin A requirements, and calculate the bioconversion and bioefficacy of food carotenoids.
... met Giovanna del Nero. Despite the misgivings of Professor Chain, who warned her that America... more ... met Giovanna del Nero. Despite the misgivings of Professor Chain, who warned her that Americans have terrible food, Giovanna agreed to tutor Olson in Italian. They subsequently married and had three children: Daniel (an attorney), Lisa (a biochemist), and Eric (a veterinarian ...
International journal for vitamin and nutrition research. Internationale Zeitschrift für Vitamin- und Ernährungsforschung. Journal international de vitaminologie et de nutrition, 1990
Surgical liver biopsy samples from seven diseased and five healthy human subjects, 3-33 years of ... more Surgical liver biopsy samples from seven diseased and five healthy human subjects, 3-33 years of age, were analyzed by reversed-phase high-pressure liquid chromatography for retinol (vitamin A alcohol), retinyl esters (vitamin A esters), and carotenoids. Total liver vitamin A values ranged from 7.8 to 2860 nmol/g liver (2.2 to 817 micrograms/g). As a percentage, liver retinol decreased with increasing liver reserves of vitamin A. Retinyl palmitate was the predominant vitamin A ester (57 to 83 mole%) in all samples, with retinyl stearate (5.5 to 11.4%), oleate (4.9 to 17.2%), and myristate plus palmitoleate (pair not resolved; 3.3 to 11.9%) next most common. Lesser amounts of retinyl linoleate, linolenate, and arachidonate were found. Normal livers had significant amounts of several carotenoids: lutein (0.2 to 16.2 nmol/g), lycopene (10.2 to 55.1 nmol/g), alpha-carotene (3.0 to 7.3 nmol/g), and beta carotene (5.8 to 25 nmol/g). Total carotenoid values ranged from 26.5 to 67 nmol/g in...
... However, you may be able to access this article under your organization's agreem... more ... However, you may be able to access this article under your organization's agreement with Elsevier. Harold C. Furr, Jason CH Shih, Earl H. Harrison, Hsien-Hsin Chang, Joseph T. Spence,Lemuel D. Wright and Donald B. McCormick. Available online 27 November 2003. Excerpt. ...
In this paper, we present a fast minimicroassay of serum vitamin A by capillary zone electrophore... more 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, espec...
The dependence of liver retinyl ester (vitamin A ester) composition on dietary fatty acid composi... more The dependence of liver retinyl ester (vitamin A ester) composition on dietary fatty acid composition was studied in rats. Weanling male Sprague-Dawley rats were fed purified test diets containing 8% of one of 10 test triglycerides (either tributyrin, tricaproin, tricaprylin, tricaprin, trilaurin, trimyristin, tripalmitin, tristearin, triolein, trilinolein) or corn oil (a mixed triglyceride) for 23 d after an initial 1-wk stabilization period. Essential fatty acids were provided by safflower oil (8 g/kg diet). Total liver fatty acid composition showed the expected responses to dietary fatty acid intake; short-chain and medium-chain fatty acids were readily elongated to palmitate and stearate, and palmitate and stearate were readily desaturated. Consumption of oleate or linoleate (as their triglycerides) markedly enriched their concentrations in liver lipids. The proportions of palmitate were generally greater in liver retinyl esters than in total liver fatty acids, and the proportio...
The vitamin A status in 11 generally healthy surgical patients was estimated by measuring the dil... more The vitamin A status in 11 generally healthy surgical patients was estimated by measuring the dilution of a 45-mg oral dose of tetradeuterated retinyl acetate (99% pure). After purification of retinol by high-performance liquid chromatography, the ratio of 2H4-retinol:1H-retinol in plasma was measured by gas chromatography-mass spectrometry. On the basis of the observed ratios of [2H4]retinol:[1H]retinol over 19-47 d, the total body reserves and liver concentrations of vitamin A were calculated. Liver biopsy samples taken at surgery were directly analyzed for vitamin A. The correlation coefficient between calculated and measured liver vitamin A concentrations for 10 of the subjects was 0.88, and the Spearman's rank correlation coefficient was 0.95 (p less than 0.002). Thus, total body reserves of vitamin A in humans can be estimated validly in the marginal and satisfactory ranges by a benign, relatively noninvasive procedure.
After an appropriate dose of 3,4-didehydroretinol (vitamin A2, DR) is given orally in corn oil to... more 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 ...
Comparative biochemistry and physiology. B, Comparative biochemistry, 1986
Acyl coenzyme A:retinol acyltransferase activity was identified in the microsomes from a polar be... more Acyl coenzyme A:retinol acyltransferase activity was identified in the microsomes from a polar bear liver. The highest rate of in vitro retinol esterification was 821 pmol/min/mg microsomal protein. The in vitro esterification rate displayed a small dependence upon the concentration of exogenous protein (bovine serum albumin) and even less on the concentration of sulfhydryl-reducing agent (dithiothreitol). Vitamin A was present in the liver at a concentration of 8050 micrograms/g tissue, with 98% of the vitamin in its ester form. Retinyl palmitate was 37.3% of the total liver retinyl esters, while retinyl oleate represented 20.9%, stearate 12.8%, and linoleate 7.7%.
Page 19. 1 Vitamin A and Carotenoids Arun B. Barua and James Allen Olson Iowa State University, A... more Page 19. 1 Vitamin A and Carotenoids Arun B. Barua and James Allen Olson Iowa State University, Ames. Iowa Harold C. Furr University of Connecticut. Storrs, Connecticut Richard B. van Breemen University of Illinois at Chicago ...
The sera of adult aquarium-held pinnipeds from four species (family Phocidae: harbor seals (Phoca... more The sera of adult aquarium-held pinnipeds from four species (family Phocidae: harbor seals (Phoca vitulina) and gray seals (Halichoerus grypus); family Otariidae: northern fur seals (Callorhinus ursinus) and California sea lions (Zalophus californianus)) were analyzed for vitamin A (retinol), vitamin E (atocopherol), total cholesterol, triglycerides, phospholipids, and fatty acids. Each subject animal was healthy at the time of blood collection, was fasted for at least 12 hr prior to sampling, and was maintained on a constant diet and supplement regime throughout the study. Retinol values for the four species ranged from 0.16 to 0.92 mg/mL, with the lowest concentrations seen in the harbor seals and the highest in the northern fur seals. Vitamin E values ranged from 10.55 to 43.58 mg/ mL, with northern fur seals showing the highest and gray seals the lowest levels. Vitamin E/lipid ratios (cholesterol, triglyceride, phospholipid, and total lipids) were also examined. A significant correlation was seen between vitamin E and total lipids (Po0.05) and phospholipid (Po0.01). Statistical analysis of the retinol, tocopherol, triglyceride, and phospholipid levels showed significant differences between phocid and otariid seals. Otariids had significantly lower tocopherol and phospholipid values (19.36 mg/mL, 4.29 mg/mL) and the phocids had significantly lower retinol and triglyceride levels (0.29 mg/mL, 124 mg/dL).
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