Selenium status of very low birth weight infants.

The selenium (Se) intake and status of 82 very low birth weight infants (birth weight 1110 +/- 286 g, gestational age 29.2 +/- 3 wk, mean +/- SD) was assessed at 36.3 +/- 3 postconceptional wk, at 40.

Copper status of very low birth weight infants during the first 12 months of infancy.

The Cu intake and status of 106 very low birth weight (VLBW) infants (birth weight 1152 +/- 251 g, gestational age 29 +/- 3 wk, mean +/- SD) were determined approximately 1 mo before hospital discharge, at discharge (time 0), and at 3, 6, 9, and 12 mo +/- 3 wk corrected for gestational age. Infants were fed either formula plus supplemental Zn/Cu (SUPPL, n = 29); formula plus placebo (PLAC, n = 26); or a low birth weight formula (LBWF, n = 26) or were breast-fed (BRMLK, n = 25). Plasma Cu levels in the formula-fed infants increased significantly at each time period with no significant differences between feeding groups.

Glutathione peroxidase activity in a healthy Canadian population. Effects of age, smoking and drinking habits, exercise and oral contraceptive use.

The activity of the enzyme glutathione peroxidase (SeGSHPx) has been suggested as an indicator of selenium status. The purpose of this study was to measure the activity of this enzyme in a large sample of healthy, free-living Canadians to determine normal distributions and the effects of age, smoking, and drinking habits, exercise, and the use of oral contraceptives (OCs) or estrogen replacement therapy. The population consisted of 386 self-selected subjects between the ages of 24 and 75.

Dietary (n-3) fatty acids affect rat heart, liver and aorta protective enzyme activities and lipid peroxidation.

In a 16-wk study, weanling Wistar rats (32 males and 32 females) were fed a modified AIN-76 diet containing 20% fat with various (n-3) fatty acids. All dietary fats provided the same amount of saturates, monounsaturates, and total essential fatty acids [(n-6) + (n-3)]. The control diet contained lard/corn oil (L/CO).

Changes in selenium and antioxidant status during DMBA-induced mammary carcinogenesis in rats.

Female weanling Sprague-Dawley rats were used to examine the changes that occurred in selenium and antioxidant status during the development of 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary tumors. Animals were fed an AIN-76 diet, modified to contain 20% fat (3:1 wt/wt, lard:corn oil) and 0.1, 0.

Effects of dietary selenium on DMBA-induced carcinogenesis in rats fed a diet high in mixed fats.

The effects of selenium intake on 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary carcinogenesis were examined in rats fed a diet high in mixed fats and representative of that consumed in North America. Six groups of 20 rats were fed an AIN-76 diet modified to contain 20% fat from lard:corn oil (3:1 wt/wt) and various amounts of selenium (0.1, 0.

Effect of dietary selenium and tumor status on the retention of 75Se by tissues and mammary tumors of DMBA-treated rats.

The effects of the presence of mammary tumors on 75Se retention was examined in DMBA-treated rats. Tumor bearing rats fed varying amounts of Se exhibited an inverse linear dose response between dietary Se intake and tissue retention of 75Se in whole body, heart, lungs, ovaries, adrenals, spleen, and muscle. Tumor 75Se retention, however, was independent of the dietary intake of Se.

Colorimetric determination of total iodine in foods by iodide-catalyzed reduction of Ce+4.

An earlier acid digestion determination of iodine in foods was modified to provide an improved detection limit and to allow for the analysis of a greater variety and larger amounts of foods. The organic material in the sample was oxidized overnight by concentrated nitric acid, followed by digestion in a mixture of concentrated sulfuric and 70% perchloric acid. The iodine was determined by an automated colorimetric method based on the iodide-catalyzed reduction of Ce+4 by As+3.

An automated method for the determination of Cu,Zn-superoxide dismutase in plasma and erythrocytes using an ABA-200 discrete analyzer.

An automated enzymatic method is described for the determination of Cu,Zn-superoxide dismutase (SOD) in plasma or erythrocytes using the xanthine-xanthine oxidase and cytochrome C coupled assay. This method was adapted to an Abbott ABA-200 discrete analyzer. Coefficients of variation for within-run and day-to-day analyses were less than 5%.

Effect of zinc supplementation on copper status in adult man.

The effects of zinc supplementation on the copper status of healthy adult men, as assessed by the activities of the copper-metalloenzymes, plasma ferroxidase (ceruloplasmin), and erythrocyte Cu,Zn-superoxide dismutase, were determined. The subjects were given either two daily doses of 25 mg zinc or placebo for 6 wk. No significant differences in the plasma copper levels or the ferroxidase activities between the supplemented and control groups could be detected at 2, 4, or 6 wk.

The effects of dietary zinc on the activity of copper-requiring metalloenzymes in the rat.

It has long been known that zinc interferes with copper absorption and metabolism. In the present study, the effects of feeding rats 15, 30, 60, 120 or 240 mg Zn/kg diet on their copper status, as assessed by the activities of cupro -zinc superoxide dismutase (SOD) and cytochrome c oxidase (CCO) in heart and liver, and ceruloplasmin (Cp) in serum were determined. Although Cp activity was not related to zinc intake in a linear fashion, the number of animals with extremely low Cp activity increased with increasing zinc.

The effects of high dietary zinc and copper deficiency on the activity of copper-requiring metalloenzymes in the growing rat.

The effects of feeding rats high levels of dietary zinc (240 mg Zn/kg diet) on the activities of the copper-requiring metalloenzymes: ceruloplasmin (Cp), cupro -zinc superoxide dismutase (SOD) and cytochrome c oxidase (CCO) were determined. These were compared with those seen during copper deficiency (induced by feeding 0.6 mg Cu/kg diet).

Effects of zinc on mucosal copper binding and on the kinetics of copper absorption.

The kinetics of serosal copper transfer and the distribution of copper between metallothionein (MT) and a high-molecular-weight protein fraction (HMWPF) within the mucosal cells were examined, using isolated duodenal segments from rats fed different amounts of zinc. No difference in the Vmax or Km for serosal transfer could be detected between the different zinc groups, suggesting that zinc did not affect this aspect of copper absorption. When intestinal segments from rats fed the low zinc diet were incubated in high copper media, the majority of the copper was associated with the HMWPF, while those from rats fed the high zinc diet had the largest proportion bound to MT.

The effect of dietary zinc on intestinal copper absorption.

Everted duodenal segments, tied into sacs, taken from animals fed different amounts of zinc were used to investigate the antagonistic effect of dietary zinc on copper absorption. The intestinal segments taken from animals fed low amounts of zinc transferred more copper from a nutrient medium across the mucosal cells than did intestines from rats fed high levels of zinc. The mucosal cells from animals fed low amounts of zinc retained less copper than the cells from animals fed high amounts of the element.

Acid digestion determination of iodine in foods.

A method for determining iodine in food is described. The samples were digested using a mixture of sulfuric, nitric, and perchloric acids. The iodine was determined by an automated colorimetric method based on the iodide-catalyzed reduction of Ce+4 by As+3.

High pressure liquid chromatographic determination of vitamin D in fortified milk.

Vitamin D was determined in fortified milk by high pressure liquid chromatography (HPLC) after preliminary purification involving saponification at room temperature and low pressure chromatography on hydroxyalkoxyprophyl Sephadex (HAPS). The saponified milk (50 ml) was extracted with ether, the extract was chromatographed in hexane on a 60 X 1 cm column of HAPS, and the absorption of the eluate at 254 nm was recorded. The fraction containing vitamin D was collected by using the position of characteristic peaks in the chromatogram as a guide.