Erythrocyte superoxide dismutase activities and erythrocyte and plasma glutathione peroxidase act... more Erythrocyte superoxide dismutase activities and erythrocyte and plasma glutathione peroxidase activities have been determined in Duchenne muscular dystrophy patients, genetic carriers, and normal controls. A 19% decrease in red cell superoxide dismutase activity was observed in patients with Duchenne muscular dystrophy. Genetic carriers showed a level between that of the dystrophy patients and the normal controls. No abnormality was seen in the red cell or plasma activities of glutathione peroxidase.
We describe a reversed-phase high-performance liquid chromatographic method for the determination... more We describe a reversed-phase high-performance liquid chromatographic method for the determination of vitamin A-transporting (holo) transthyretin-bound (TTR) retinol-binding protein (RBP) concentrations in serum or plasma. Holo-TTR-RBP and free retinol derived primarily from free RBP are consistently observed with this chromatographic method. Holo-TTR-RBP concentrations determined by this method are highly correlated to holo-TTR-RBP concentrations measured by chromatography. This method has the advantage of using less expensive columns and having peak areas which are more proportional to their true concentrations in plasma, as determined by comparison to purified protein spectrophotometry and radial immunodiffusion. The percentage of RBP circulating as holo-TTR-RBP decreased significantly as the total concentration of RBP or retinol increased. Because purified holo-TTR-RBP did not dissociate under these chromatographic conditions, this suggests that more vitamin A circulates as holo-...
California is a major producer of tangerines and oranges, which contain carotenoids that form vit... more California is a major producer of tangerines and oranges, which contain carotenoids that form vitamin A. Deficiencies of this vitamin are common in southern Asia and Africa, causing blindness and more than one-half million deaths each year. We evaluated the potential of ...
Boiled biofortified cassava containing β-carotene can increase retinyl palmitate in triacylglycer... more Boiled biofortified cassava containing β-carotene can increase retinyl palmitate in triacylglycerol-rich plasma. Thus, it might alleviate vitamin A deficiency. Cassava requires extensive preparation to decrease its level of cyanogenic glucosides, which can be fatal. Garification is a popular method of preparing cassava that removes cyanogen glucosides. Our objective was to compare the effectiveness of biofortified gari to gari prepared with red palm oil. The study was a randomized crossover trial in 8 American women. Three gari preparations separated by 2-week washout periods were consumed. Treatments (containing 200-225.9 g gari) were as follows: biofortified gari (containing 1 mg β-carotene), red palm oil-fortified gari (1 mg β-carotene), and unfortified gari with a 0.3-mg retinyl palmitate reference dose. Blood was collected 6 times from -0.5 to 9.5 hours after ingestion. Triacylglycerol-rich plasma was separated by ultracentrifugation and analyzed by high-performance liquid chro...
Beta-cryptoxanthin is a common carotenoid. It is generally the fourth most abundant in human bloo... more Beta-cryptoxanthin is a common carotenoid. It is generally the fourth most abundant in human blood but can achieve high concentrations especially in Japanese and Spanish populations. Its richest food sources include mandarin oranges, persimmons, oranges, papayas, pumpkin, and red sweet peppers. Beta-cryptoxanthin appears to be absorbed better from its major food sources than other carotenoids, and thus may be more important for human health than previously assumed. Beta-cryptoxanthin has multiple functions and actions that may be important for human health. First, beta-cryptoxanthin is a precursor of vitamin A. Vitamin A is an essential nutrient needed for eyesight, growth, development, and immune response. Second, like all carotenoids, beta-cryptoxanthin is an antioxidant. Thus, it may help protect against some cancers and other degenerative diseases. Finally, some interesting studies in cell lines and animals suggest that beta-cryptoxanthin may have an anabolic effect on bone, thu...
The search for a reliable, convenient indicator of Zn status was the focus of research for severa... more The search for a reliable, convenient indicator of Zn status was the focus of research for several decades. Plasma Zn concentration is still the most widely used clinical measurement, despite the known problems of interpretation. More recently, researchers suggested that isotopically determined kinetic parameters, such as the exchangeable Zn pool (EZP), may more accurately and reliably reflect body Zn status. The objective of this study was to examine the relationship between net body Zn loss and gain during acute changes in dietary Zn intake with biochemical and kinetic indices of Zn status. Five men participated in an 85-d Zn depletion/repletion study. Net body Zn loss and gain were determined from the difference between dietary plus intravenously administered Zn and Zn excretion. Biochemical indicators of Zn status included plasma Zn, plasma alkaline phosphatase activity, and plasma retinol binding protein concentration. Following intravenous administration of (70)Zn or (67)Zn, a...
Isotope tracer studies, particularly radiocarbon measurements, play a key role in biological, nut... more Isotope tracer studies, particularly radiocarbon measurements, play a key role in biological, nutritional, and environmental research. Accelerator mass spectrometry (AMS) is now the most sensitive detection method for 14C, but AMS is not widely used in kinetic studies of humans. Part of the reason is the expense, but costs would decrease if AMS were used more widely. One component in
Erythrocyte superoxide dismutase activities and erythrocyte and plasma glutathione peroxidase act... more Erythrocyte superoxide dismutase activities and erythrocyte and plasma glutathione peroxidase activities have been determined in Duchenne muscular dystrophy patients, genetic carriers, and normal controls. A 19% decrease in red cell superoxide dismutase activity was observed in patients with Duchenne muscular dystrophy. Genetic carriers showed a level between that of the dystrophy patients and the normal controls. No abnormality was seen in the red cell or plasma activities of glutathione peroxidase.
We describe a reversed-phase high-performance liquid chromatographic method for the determination... more We describe a reversed-phase high-performance liquid chromatographic method for the determination of vitamin A-transporting (holo) transthyretin-bound (TTR) retinol-binding protein (RBP) concentrations in serum or plasma. Holo-TTR-RBP and free retinol derived primarily from free RBP are consistently observed with this chromatographic method. Holo-TTR-RBP concentrations determined by this method are highly correlated to holo-TTR-RBP concentrations measured by chromatography. This method has the advantage of using less expensive columns and having peak areas which are more proportional to their true concentrations in plasma, as determined by comparison to purified protein spectrophotometry and radial immunodiffusion. The percentage of RBP circulating as holo-TTR-RBP decreased significantly as the total concentration of RBP or retinol increased. Because purified holo-TTR-RBP did not dissociate under these chromatographic conditions, this suggests that more vitamin A circulates as holo-...
California is a major producer of tangerines and oranges, which contain carotenoids that form vit... more California is a major producer of tangerines and oranges, which contain carotenoids that form vitamin A. Deficiencies of this vitamin are common in southern Asia and Africa, causing blindness and more than one-half million deaths each year. We evaluated the potential of ...
Boiled biofortified cassava containing β-carotene can increase retinyl palmitate in triacylglycer... more Boiled biofortified cassava containing β-carotene can increase retinyl palmitate in triacylglycerol-rich plasma. Thus, it might alleviate vitamin A deficiency. Cassava requires extensive preparation to decrease its level of cyanogenic glucosides, which can be fatal. Garification is a popular method of preparing cassava that removes cyanogen glucosides. Our objective was to compare the effectiveness of biofortified gari to gari prepared with red palm oil. The study was a randomized crossover trial in 8 American women. Three gari preparations separated by 2-week washout periods were consumed. Treatments (containing 200-225.9 g gari) were as follows: biofortified gari (containing 1 mg β-carotene), red palm oil-fortified gari (1 mg β-carotene), and unfortified gari with a 0.3-mg retinyl palmitate reference dose. Blood was collected 6 times from -0.5 to 9.5 hours after ingestion. Triacylglycerol-rich plasma was separated by ultracentrifugation and analyzed by high-performance liquid chro...
Beta-cryptoxanthin is a common carotenoid. It is generally the fourth most abundant in human bloo... more Beta-cryptoxanthin is a common carotenoid. It is generally the fourth most abundant in human blood but can achieve high concentrations especially in Japanese and Spanish populations. Its richest food sources include mandarin oranges, persimmons, oranges, papayas, pumpkin, and red sweet peppers. Beta-cryptoxanthin appears to be absorbed better from its major food sources than other carotenoids, and thus may be more important for human health than previously assumed. Beta-cryptoxanthin has multiple functions and actions that may be important for human health. First, beta-cryptoxanthin is a precursor of vitamin A. Vitamin A is an essential nutrient needed for eyesight, growth, development, and immune response. Second, like all carotenoids, beta-cryptoxanthin is an antioxidant. Thus, it may help protect against some cancers and other degenerative diseases. Finally, some interesting studies in cell lines and animals suggest that beta-cryptoxanthin may have an anabolic effect on bone, thu...
The search for a reliable, convenient indicator of Zn status was the focus of research for severa... more The search for a reliable, convenient indicator of Zn status was the focus of research for several decades. Plasma Zn concentration is still the most widely used clinical measurement, despite the known problems of interpretation. More recently, researchers suggested that isotopically determined kinetic parameters, such as the exchangeable Zn pool (EZP), may more accurately and reliably reflect body Zn status. The objective of this study was to examine the relationship between net body Zn loss and gain during acute changes in dietary Zn intake with biochemical and kinetic indices of Zn status. Five men participated in an 85-d Zn depletion/repletion study. Net body Zn loss and gain were determined from the difference between dietary plus intravenously administered Zn and Zn excretion. Biochemical indicators of Zn status included plasma Zn, plasma alkaline phosphatase activity, and plasma retinol binding protein concentration. Following intravenous administration of (70)Zn or (67)Zn, a...
Isotope tracer studies, particularly radiocarbon measurements, play a key role in biological, nut... more Isotope tracer studies, particularly radiocarbon measurements, play a key role in biological, nutritional, and environmental research. Accelerator mass spectrometry (AMS) is now the most sensitive detection method for 14C, but AMS is not widely used in kinetic studies of humans. Part of the reason is the expense, but costs would decrease if AMS were used more widely. One component in
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Papers by Betty Burri