Phyllis Johnson | University of North Dakota (original) (raw)

Papers by Phyllis Johnson

Research paper thumbnail of Determination of zinc availability in foods by the extrinsic label technique1'2

The absorption of intrinsic 65Zn and extrinsic 65Zn from corn and liver was measured in rats. No ... more The absorption of intrinsic 65Zn and extrinsic 65Zn from corn and liver was measured in rats. No significant difference between the absorption of intrinsic- and extrinsic-label was observed. These results indicate that endogenous zinc and exogenous 65Zn enter a common pool prior to being absorbed from the intestine. Since extrinsic 65Zn enters a common pool with intrinsic zinc, whole-body absorption of extrinsic 65Zn can be used to obtain an accurate estimate of the availability of zinc in food. The availability of zinc in human breast milk, in cow's milk, in infant formulas, and in reconstituted dry milk was analyzed by use of the extrinsic label. The zinc in human breast milk was most available (59%) while the zinc in the infant formulas was the least available (26 to 37%). Zinc from both raw and cooked corn was more available than zinc from either cooked or uncooked rat liver.

Research paper thumbnail of Evaluation of foliar application and stem injection as techniques for intrinsically labeling wheat with copper-65

Journal of Agricultural and Food Chemistry, 1986

Research paper thumbnail of Binding of zinc and copper to some gel filtration media

Journal of Chromatography A, 1980

Biding of zinc 2nd capper ti uIme gel fi W&on media Gel iSration chromatography is a widely used ... more Biding of zinc 2nd capper ti uIme gel fi W&on media Gel iSration chromatography is a widely used technique. Many of the substances purifkd by this method are metalloenzymes or other metalloproteins. In addition to its use as a method of puritkation, gei filtration has been used to determine the stability constants of various metal-ligand or met&protein complexesl".

Research paper thumbnail of Effects of Level and Saturation of Fat and Iron Level and Type in the Diet on IronAbsorption and Utilization by the Rat1

Two 2 X 2 X 2 factorial studies were done to examine the effects of dietary iron level (10 or 35 ... more Two 2 X 2 X 2 factorial studies were done to examine the effects of dietary iron level (10 or 35 ppm), percent dietary fat (5 or 30%) and type of fat (safflower or coconut oil) on heme or nonheme iron absorption and other indices of iron status in rats (liver Fe, Hb, delta Hb). Rats were made moderately anemic (Hb 7.8 +/- 0.7 g/dL) by feeding an iron-deficient diet and were then fed one of the 16 experimental diets. Test meals (100 micrograms Fe) labeled with 59Fe were fed after 5 d and 59Fe absorption determined by whole-body counting. Rats were killed after 5 wk and liver Fe, final Hb and delta Hb were determined. Nonheme iron was better absorbed than heme iron regardless of other dietary factors. Both heme iron absorption and nonheme iron absorption were higher when high (30%) rather than low (5%) dietary fat was fed. The type of fat had no effect. Rats fed both nonheme and heme iron had significantly higher Hb, delta Hb and liver iron when fed coconut oil, compared to safflower oil. Rats fed nonheme iron had higher liver Fe, but not Hb or delta Hb, when fed high rather than low dietary fat. Rats fed heme iron had higher Hb, delta Hb and liver Fe when fed high fat than low fat.

Research paper thumbnail of A Mass Spectrometric Method for Use of Stable Isotopes as Tracers in Studies of Iron, Zinc, and Copper Absorption in Human Subjects

Stable isotopes of iron, zinc, and copper can be used singly and in combination as tracers of min... more Stable isotopes of iron, zinc, and copper can be used singly and in combination as tracers of mineral metabolism in human subjects. A mass spectrometric method of analysis that uses chelation of these metals with tetraphenylporphyrin was developed. Absorption can be determined by measuring isotope appearance in feces after a single pulse dose. The method is satisfactory for MFe, 67Zn,and^Cu. Detection of 57Fe and 70Znin feces is not very reliable.

Research paper thumbnail of Determination, stable isotope enrichment and kinetics of direct-reacting copper in blood plasma

Journal of Nutritional Biochemistry, 1996

Research paper thumbnail of Techniques for intrinsically labeling wheat with zinc-65

Journal of Agricultural and Food Chemistry, 1985

Research paper thumbnail of Absorption of zinc and iron by rats fed meals containing sorghum food products†

Journal of Cereal Science, 1987

Zinc and iron absorption from freeze-dried, traditionally prepared sorghum food products was stud... more Zinc and iron absorption from freeze-dried, traditionally prepared sorghum food products was studied in rats. Following a period of marginal zinc or iron depletion, groups of rats (n = 6 in each group) were fed nutrient-balanced test meals containing one of four sorghum food products (fermented aceda ; acidic tô, cooked with tamarind extract; neutral tô, cooked in water; alkaline tô, cooked with wood ash), cooked maize gruel or an egg-white control diet, each of which was extrinsically labeled with either 65Zn or 59Fe before being added to the diets. Absorption was determined by whole-body retention of the initial radioisotope dose over a period of 19 days. Iron was highly available from all products tested (75–83%) with no significant difference in absorption between groups. Zinc from fermented aceda (97%) was more available than that from the other sorghum products (69–78%) or maize gruel (76%) (P < 0·05). There was no significant difference in zinc absorption between groups fed acidic tô (78%), neutral tô (76%), alkaline tô (69%) or maize gruel (76%). The phytate content of the fermented aceda was 33% lower than that of the other sorghum foods.

Research paper thumbnail of Boron isotope ratios in commercial produce and boron-10 foliar and hydroponic enriched plants

Journal of Agricultural and Food Chemistry, 1992

... Blood boron levels might be transiently defined by a single meal or highly influenced by a sn... more ... Blood boron levels might be transiently defined by a single meal or highly influenced by a snack. For example, one medium banana (119 g) (Guthrie, 1983) with 5.8 pg of B/g of wet weight (Table 11) could contribute 690 pg of boron. ...

Research paper thumbnail of Bioavailability in humans of zinc from beef: intrinsicvs extrinsic IabeIs16

Research paper thumbnail of Copper65 absorption by men fed intrinsically and extrinsically labeled whole wheat bread

Journal of Agricultural and Food Chemistry, 1988

The user has requested enhancement of the downloaded file.

Research paper thumbnail of Effect of past and current dietary Zn intake on Zn absorption and endogenous excretion in the rat

Effects of previous dietary Zn (or body Zn stores) and current dietary Zn intake on absorption an... more Effects of previous dietary Zn (or body Zn stores) and current dietary Zn intake on absorption and endogenous excretion of Zn were studied by using radioisotope dilution. Rats were fed diets containing 1.5, 12.6 or 50.3 mg Zn/kg for 19 d (dietary period I). Total body Zn in the three groups was 1870 ±340, 3953 ±698 and 4126 ±844 (¿g Zn rat. Each group was divided into four subgroups fed 3.6, 12.6, 20.5 or 50.3 mg Zn/kg diet for 3 wk (dietary period II). Rats were injected intramus cularly with 65Zn after 7 d of dietary period II. True ab

Research paper thumbnail of Sex affects manganese absorption and retention by humans from a diet adequate in manganese14

Men (n = 20) and women (n = 20) consuming a diet adequate in manganese were fed 0.037 mBq MMn in ... more Men (n = 20) and women (n = 20) consuming a diet adequate in manganese were fed 0.037 mBq MMn in a test pend on the portion of the data used. Am J Clin Nutr l994;60:949-55.

Research paper thumbnail of Absorption and Organ Content of Cadmium from the Kernels of Confectionery Sunflowers (Helianthus annuus) Fed to Male Rats

Journal of Agricultural and Food Chemistry, 1994

The purpose of this study was to determine the availability of cadmium from the kernels of sunflo... more The purpose of this study was to determine the availability of cadmium from the kernels of sunflowers grown in soils containing a natural abundance of cadmium. Weanling male rats were used as the experimental model. Fresh sunflower kernels containing either 330 or 780 pg Cd/kg ...

Research paper thumbnail of Effects of dietary zinc depletion on seminal volume and zinc loss, serum testosterone concentrations, and sperm morphology in young men14

... morphology in young men14 Curtiss D Hunt, Phyllis E Johnson, JoLavne Herbel, and Loanne K Mul... more ... morphology in young men14 Curtiss D Hunt, Phyllis E Johnson, JoLavne Herbel, and Loanne K Mullen ABSTRACT Identification of the andrological variables ... d as three lg calcium gluconate tablets providing 90 mg ele-mental Ca each (Eli Lilly and Co. ...

Research paper thumbnail of Homeostatic control of zinc metabolism in men: zinc excretion and balance in men fed diets low in zinc13

Zinc metabolism was studied in I I men. The study began with 28-d equilibration when dietary zinc... more Zinc metabolism was studied in I I men. The study began with 28-d equilibration when dietary zinc was 159

Research paper thumbnail of Effects of age and sex on copper absorption, biological half-life, and status in human&3

Healthy, free-living men and women aged 20-83 y (n = 1 27) were studied to determine the effects ... more Healthy, free-living men and women aged 20-83 y (n = 1 27) were studied to determine the effects of age and sex on copper absorption, biological half-life (BH), and status. quirements may differ between men and women. Am J C/in Nutr 1992;56:9 17-25.

Research paper thumbnail of Relative zinc availability in human breast milk, infant formulas, and cow's milk1' 2

Page 1. 416 The American Journal of Clinical Nutrition 31: MARCH 1978, pp. 416-421. Printed in US... more Page 1. 416 The American Journal of Clinical Nutrition 31: MARCH 1978, pp. 416-421. Printed in USA Relative zinc availability in human breast milk, infant formulas, and cow&amp;amp;amp;amp;amp;#x27;s milk1&amp;amp;amp;amp;amp;#x27; 2 Phyllis E. Johnson,3 Ph.D. and Gary W. Evans,4 Ph.D. ...

Research paper thumbnail of Detection of labile zinc-binding ligands in biological fluids by modified gel filtration chromatography

Analytical Chemistry, 1979

Page 1. ANALYTICAL CHEMISTRY, VOL. 51, NO. 7, JUNE 1979 839 pacity commercially purchased anion-e... more Page 1. ANALYTICAL CHEMISTRY, VOL. 51, NO. 7, JUNE 1979 839 pacity commercially purchased anion-exchange column, and work. (10) Y. Takata and G. Muto, Anal. Chem., 45, 1864 (1973). (11) Y . Takata and K. Fujita, J. Chromatogr., 108, 225 (1975). ...

Research paper thumbnail of Characterization and Quantitation of a Zinc-Binding Ligand in Human Milk

Pediatric Research, 1980

A low-molecular-weight zinc-binding ligand from human milk has been isolated and characterized. T... more A low-molecular-weight zinc-binding ligand from human milk has been isolated and characterized. The ligand was isolated by chromatography on Dowex 50, Dowex 1, and Sephadex G-15 equilibrated with 0.153 mM Zn(NO3)2. Mass spectroscopy, thin-layer chromatography, and infrared spectroscopy proved that the zinc-binding ligand isolated by this method from human milk is pyridine-2-carboxylic acid, commonly known as picolinic acid. The concentration of picolinic acid in human milk was 308 microM, the concentration in one brand of processed cow&#39;s milk was 20 microM, but picolinic acid was undetectable in a second brand of cow&#39;s milk and in four different infant formulas. Weanling rats fed supplemental picolinic acid absorbed significantly more dietary zinc and gained significantly more weight than rats fed an unsupplemented diet. The results suggest that the high bioavailability of zinc in human milk results from the presence of picolinic acid, a bidentate chelating ligand which facilitates zinc absorption from the intestine.

Research paper thumbnail of Determination of zinc availability in foods by the extrinsic label technique1'2

The absorption of intrinsic 65Zn and extrinsic 65Zn from corn and liver was measured in rats. No ... more The absorption of intrinsic 65Zn and extrinsic 65Zn from corn and liver was measured in rats. No significant difference between the absorption of intrinsic- and extrinsic-label was observed. These results indicate that endogenous zinc and exogenous 65Zn enter a common pool prior to being absorbed from the intestine. Since extrinsic 65Zn enters a common pool with intrinsic zinc, whole-body absorption of extrinsic 65Zn can be used to obtain an accurate estimate of the availability of zinc in food. The availability of zinc in human breast milk, in cow&#39;s milk, in infant formulas, and in reconstituted dry milk was analyzed by use of the extrinsic label. The zinc in human breast milk was most available (59%) while the zinc in the infant formulas was the least available (26 to 37%). Zinc from both raw and cooked corn was more available than zinc from either cooked or uncooked rat liver.

Research paper thumbnail of Evaluation of foliar application and stem injection as techniques for intrinsically labeling wheat with copper-65

Journal of Agricultural and Food Chemistry, 1986

Research paper thumbnail of Binding of zinc and copper to some gel filtration media

Journal of Chromatography A, 1980

Biding of zinc 2nd capper ti uIme gel fi W&on media Gel iSration chromatography is a widely used ... more Biding of zinc 2nd capper ti uIme gel fi W&on media Gel iSration chromatography is a widely used technique. Many of the substances purifkd by this method are metalloenzymes or other metalloproteins. In addition to its use as a method of puritkation, gei filtration has been used to determine the stability constants of various metal-ligand or met&protein complexesl".

Research paper thumbnail of Effects of Level and Saturation of Fat and Iron Level and Type in the Diet on IronAbsorption and Utilization by the Rat1

Two 2 X 2 X 2 factorial studies were done to examine the effects of dietary iron level (10 or 35 ... more Two 2 X 2 X 2 factorial studies were done to examine the effects of dietary iron level (10 or 35 ppm), percent dietary fat (5 or 30%) and type of fat (safflower or coconut oil) on heme or nonheme iron absorption and other indices of iron status in rats (liver Fe, Hb, delta Hb). Rats were made moderately anemic (Hb 7.8 +/- 0.7 g/dL) by feeding an iron-deficient diet and were then fed one of the 16 experimental diets. Test meals (100 micrograms Fe) labeled with 59Fe were fed after 5 d and 59Fe absorption determined by whole-body counting. Rats were killed after 5 wk and liver Fe, final Hb and delta Hb were determined. Nonheme iron was better absorbed than heme iron regardless of other dietary factors. Both heme iron absorption and nonheme iron absorption were higher when high (30%) rather than low (5%) dietary fat was fed. The type of fat had no effect. Rats fed both nonheme and heme iron had significantly higher Hb, delta Hb and liver iron when fed coconut oil, compared to safflower oil. Rats fed nonheme iron had higher liver Fe, but not Hb or delta Hb, when fed high rather than low dietary fat. Rats fed heme iron had higher Hb, delta Hb and liver Fe when fed high fat than low fat.

Research paper thumbnail of A Mass Spectrometric Method for Use of Stable Isotopes as Tracers in Studies of Iron, Zinc, and Copper Absorption in Human Subjects

Stable isotopes of iron, zinc, and copper can be used singly and in combination as tracers of min... more Stable isotopes of iron, zinc, and copper can be used singly and in combination as tracers of mineral metabolism in human subjects. A mass spectrometric method of analysis that uses chelation of these metals with tetraphenylporphyrin was developed. Absorption can be determined by measuring isotope appearance in feces after a single pulse dose. The method is satisfactory for MFe, 67Zn,and^Cu. Detection of 57Fe and 70Znin feces is not very reliable.

Research paper thumbnail of Determination, stable isotope enrichment and kinetics of direct-reacting copper in blood plasma

Journal of Nutritional Biochemistry, 1996

Research paper thumbnail of Techniques for intrinsically labeling wheat with zinc-65

Journal of Agricultural and Food Chemistry, 1985

Research paper thumbnail of Absorption of zinc and iron by rats fed meals containing sorghum food products†

Journal of Cereal Science, 1987

Zinc and iron absorption from freeze-dried, traditionally prepared sorghum food products was stud... more Zinc and iron absorption from freeze-dried, traditionally prepared sorghum food products was studied in rats. Following a period of marginal zinc or iron depletion, groups of rats (n = 6 in each group) were fed nutrient-balanced test meals containing one of four sorghum food products (fermented aceda ; acidic tô, cooked with tamarind extract; neutral tô, cooked in water; alkaline tô, cooked with wood ash), cooked maize gruel or an egg-white control diet, each of which was extrinsically labeled with either 65Zn or 59Fe before being added to the diets. Absorption was determined by whole-body retention of the initial radioisotope dose over a period of 19 days. Iron was highly available from all products tested (75–83%) with no significant difference in absorption between groups. Zinc from fermented aceda (97%) was more available than that from the other sorghum products (69–78%) or maize gruel (76%) (P < 0·05). There was no significant difference in zinc absorption between groups fed acidic tô (78%), neutral tô (76%), alkaline tô (69%) or maize gruel (76%). The phytate content of the fermented aceda was 33% lower than that of the other sorghum foods.

Research paper thumbnail of Boron isotope ratios in commercial produce and boron-10 foliar and hydroponic enriched plants

Journal of Agricultural and Food Chemistry, 1992

... Blood boron levels might be transiently defined by a single meal or highly influenced by a sn... more ... Blood boron levels might be transiently defined by a single meal or highly influenced by a snack. For example, one medium banana (119 g) (Guthrie, 1983) with 5.8 pg of B/g of wet weight (Table 11) could contribute 690 pg of boron. ...

Research paper thumbnail of Bioavailability in humans of zinc from beef: intrinsicvs extrinsic IabeIs16

Research paper thumbnail of Copper65 absorption by men fed intrinsically and extrinsically labeled whole wheat bread

Journal of Agricultural and Food Chemistry, 1988

The user has requested enhancement of the downloaded file.

Research paper thumbnail of Effect of past and current dietary Zn intake on Zn absorption and endogenous excretion in the rat

Effects of previous dietary Zn (or body Zn stores) and current dietary Zn intake on absorption an... more Effects of previous dietary Zn (or body Zn stores) and current dietary Zn intake on absorption and endogenous excretion of Zn were studied by using radioisotope dilution. Rats were fed diets containing 1.5, 12.6 or 50.3 mg Zn/kg for 19 d (dietary period I). Total body Zn in the three groups was 1870 ±340, 3953 ±698 and 4126 ±844 (¿g Zn rat. Each group was divided into four subgroups fed 3.6, 12.6, 20.5 or 50.3 mg Zn/kg diet for 3 wk (dietary period II). Rats were injected intramus cularly with 65Zn after 7 d of dietary period II. True ab

Research paper thumbnail of Sex affects manganese absorption and retention by humans from a diet adequate in manganese14

Men (n = 20) and women (n = 20) consuming a diet adequate in manganese were fed 0.037 mBq MMn in ... more Men (n = 20) and women (n = 20) consuming a diet adequate in manganese were fed 0.037 mBq MMn in a test pend on the portion of the data used. Am J Clin Nutr l994;60:949-55.

Research paper thumbnail of Absorption and Organ Content of Cadmium from the Kernels of Confectionery Sunflowers (Helianthus annuus) Fed to Male Rats

Journal of Agricultural and Food Chemistry, 1994

The purpose of this study was to determine the availability of cadmium from the kernels of sunflo... more The purpose of this study was to determine the availability of cadmium from the kernels of sunflowers grown in soils containing a natural abundance of cadmium. Weanling male rats were used as the experimental model. Fresh sunflower kernels containing either 330 or 780 pg Cd/kg ...

Research paper thumbnail of Effects of dietary zinc depletion on seminal volume and zinc loss, serum testosterone concentrations, and sperm morphology in young men14

... morphology in young men14 Curtiss D Hunt, Phyllis E Johnson, JoLavne Herbel, and Loanne K Mul... more ... morphology in young men14 Curtiss D Hunt, Phyllis E Johnson, JoLavne Herbel, and Loanne K Mullen ABSTRACT Identification of the andrological variables ... d as three lg calcium gluconate tablets providing 90 mg ele-mental Ca each (Eli Lilly and Co. ...

Research paper thumbnail of Homeostatic control of zinc metabolism in men: zinc excretion and balance in men fed diets low in zinc13

Zinc metabolism was studied in I I men. The study began with 28-d equilibration when dietary zinc... more Zinc metabolism was studied in I I men. The study began with 28-d equilibration when dietary zinc was 159

Research paper thumbnail of Effects of age and sex on copper absorption, biological half-life, and status in human&3

Healthy, free-living men and women aged 20-83 y (n = 1 27) were studied to determine the effects ... more Healthy, free-living men and women aged 20-83 y (n = 1 27) were studied to determine the effects of age and sex on copper absorption, biological half-life (BH), and status. quirements may differ between men and women. Am J C/in Nutr 1992;56:9 17-25.

Research paper thumbnail of Relative zinc availability in human breast milk, infant formulas, and cow's milk1' 2

Page 1. 416 The American Journal of Clinical Nutrition 31: MARCH 1978, pp. 416-421. Printed in US... more Page 1. 416 The American Journal of Clinical Nutrition 31: MARCH 1978, pp. 416-421. Printed in USA Relative zinc availability in human breast milk, infant formulas, and cow&amp;amp;amp;amp;amp;#x27;s milk1&amp;amp;amp;amp;amp;#x27; 2 Phyllis E. Johnson,3 Ph.D. and Gary W. Evans,4 Ph.D. ...

Research paper thumbnail of Detection of labile zinc-binding ligands in biological fluids by modified gel filtration chromatography

Analytical Chemistry, 1979

Page 1. ANALYTICAL CHEMISTRY, VOL. 51, NO. 7, JUNE 1979 839 pacity commercially purchased anion-e... more Page 1. ANALYTICAL CHEMISTRY, VOL. 51, NO. 7, JUNE 1979 839 pacity commercially purchased anion-exchange column, and work. (10) Y. Takata and G. Muto, Anal. Chem., 45, 1864 (1973). (11) Y . Takata and K. Fujita, J. Chromatogr., 108, 225 (1975). ...

Research paper thumbnail of Characterization and Quantitation of a Zinc-Binding Ligand in Human Milk

Pediatric Research, 1980

A low-molecular-weight zinc-binding ligand from human milk has been isolated and characterized. T... more A low-molecular-weight zinc-binding ligand from human milk has been isolated and characterized. The ligand was isolated by chromatography on Dowex 50, Dowex 1, and Sephadex G-15 equilibrated with 0.153 mM Zn(NO3)2. Mass spectroscopy, thin-layer chromatography, and infrared spectroscopy proved that the zinc-binding ligand isolated by this method from human milk is pyridine-2-carboxylic acid, commonly known as picolinic acid. The concentration of picolinic acid in human milk was 308 microM, the concentration in one brand of processed cow&#39;s milk was 20 microM, but picolinic acid was undetectable in a second brand of cow&#39;s milk and in four different infant formulas. Weanling rats fed supplemental picolinic acid absorbed significantly more dietary zinc and gained significantly more weight than rats fed an unsupplemented diet. The results suggest that the high bioavailability of zinc in human milk results from the presence of picolinic acid, a bidentate chelating ligand which facilitates zinc absorption from the intestine.