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Biomedical subjects

J G Fischer

Publications and source records attributed to J G Fischer.

10 recordsLinked to original sources
PubMed1999

High dietary iron enhances oxidative stress in liver but does not increase aberrant crypt foci development in rats with low vitamin E status.

The purpose of this study was to examine the effects of high-iron and low-vitamin E diets on lipid peroxidation and aberrant crypt foci (ACF) development in rats. In a 2 x 2 x 2 factorial design, male Sprague-Dawley rats were fed 45 or 450 mg Fe/kg diet (adequate and high iron, respectively) and 15 or 100 IU vitamin E/kg diet (low and adequate vitamin E, respectively) for three weeks, when they received saline or azoxymethane (15 mg/kg for 2 wk). Diets were continued for an additional six weeks. Serum alpha-tocopherol concentrations in rats fed low-vitamin E diets were decreased to 30% of concentrations observed in rats fed adequate-vitamin E diets (p < 0.0001). Also, serum alpha-tocopherol concentrations tended to be lower in rats supplemented with iron (p < 0.08). Lipid peroxidation in liver was significantly elevated by high-iron diets after 3 and 10 weeks of treatment, but lipid peroxidation in colonic mucosa was not altered by dietary iron or vitamin E. The total number of ACF and number of large ACF (> or = 4 aberrant crypts/focus) were not significantly altered by iron or vitamin E intakes. However, the size distribution of ACF was slightly altered, such that iron-supplemented rats had 12% more ACF with two crypts per focus (p < 0.02) than rats fed adequate-iron diets. Our data suggest that high-iron diets enhanced oxidative stress in liver, but not colon, of rats fed low-vitamin E diets. Furthermore, a high-iron diet does not increase the total number of ACF, even when vitamin E status is low.

Animals↗
PubMed1998

Iron supplementation does not affect cell proliferation or aberrant crypt foci development in the colon of sprague-dawley rats.

It has been suggested that high iron stores enhance colon carcinogenesis. The effect of high dietary iron (Fe) on indices of iron, copper (Cu) and manganese (Mn) status, lipid peroxidation using the thiobarbituric acid reactive substances assay, superoxide dismutase, glutathione peroxidase, glutathione transferase and ceruloplasmin activities, cell proliferation and development of preneoplastic lesions known as aberrant crypt foci (ACF) in rat colon was examined using a 3 x 2 factorial design. Male weanling Sprague-Dawley rats were fed adequate (AFe; 45 mg Fe/kg diet), moderately high (MHFe; 225 mg Fe/kg diet) and high (HFe; 450 mg Fe/kg diet) dietary Fe for 2.5 wk, then treated with azoxymethane (AOM; 2 injections, 1 wk apart; total dose 30 mg/kg body weight) or saline (n = 14-15 per group). Dietary treatment continued for another 6 wk after the second AOM dose. At the time of AOM injection, colon Fe concentrations were one- and threefold higher for MHFe and HFe rats, respectively, than for AFe rats. It was proposed that high dietary Fe would adversely affect Cu and Mn status, resulting in impaired antioxidant enzyme activity. However, neither indices of Cu and Mn status nor colonic mucosal antioxidant enzyme activities were affected by dietary Fe except for plasma ceruloplasmin activity, which was slightly lower in rats fed high iron diets than in rats fed adequate iron diets (P < 0.01). Dietary Fe had no significant effect on colonic mucosal lipid peroxidation, cell proliferation or ACF development. In conclusion, our findings suggest that dietary Fe concentrations that are approximately 5 and 10 times adequate do not enhance oxidative stress, cell proliferation and ACF development in the colon of rats.

Animals↗
PubMed1998

Milk consumption in older Americans.

OBJECTIVES: The purpose of this study was to identify individual characteristics associated with types and frequency of milk consumption in older American adults. METHODS: A national probability-based sample (response rate = 91%) completed a telephone survey. Generalized logit and cumulative logit analyses were used to identify predictors of and barriers to fluid milk consumption in 494 elderly people. RESULTS: The likelihood of drinking skim or 1% milk rather than whole milk increased with nutrition knowledge, income, trying to reduce cholesterol intake, and being female (P < .05). Frequency of milk consumption was higher with nutrition knowledge, frequency of milk consumption during adolescence, and following a diabetic diet but was lower with milk intolerance. CONCLUSIONS: The present results could be used to develop intervention strategies for improving milk consumption rates among older adults. These strategies might focus on increasing elderly people's awareness of milk intolerance and lactose-reduced milk products and their concern about cholesterol. The relationship between current and adolescent milk consumption suggests that intervention strategies should begin early in life.

Adolescent↗
PubMed1996

Analysis of pressurized resistance vessel diameter changes with a low cost digital image processing device.

A low cost digital image processing device (frame grabber) together with a program running under MS_WINDOWS for automatic on-line analysis of diameter changes of in vitro pressurized blood vessels with an inner diameter of 80-400 microns is presented. The frame grabber is designed to receive light microscopic images either from a video camera or from a VCR and to present the digitized image on the computer monitor. The special software allows to manipulate the image, e.g. filtering, calibrating, storing of vessel images, and detects the outer and inner border of the two vessel walls with a new, simple algorithm. The inner diameter and the vessel wall thickness are calculated and the diameter is presented in a diameter versus time diagram on the monitor screen. Further, these data are stored in an ASCII-file for later import into calculation and presentation programs like MS-EXCEL.

Algorithms↗
PubMed1996

Developing an instrument to measure the influence of knowledge, behaviors, and attitudes on milk consumption patterns in older participants of a community wellness group: a pilot study.

An instrument was developed to assess the relationship between knowledge of dairy products and milk consumption in participants of a community wellness program (age = 50 to 89; n = 103). Multiple regression analyses indicated that consumption of lower fat milk was predicted by nutrition knowledge and trying to reduce fat intake (R2 = .19, p < or = .0001), whereas, frequency of milk intake was predicted by milk consumption during youth, following a weight loss diet, and attitudes related to spoilage, packaging and expense (R2 = .24, p < or = .0001). Thus, nutrition knowledge about dairy products is a better predictor of the type of milk consumed rather than the frequency of milk consumption.

Aged↗
PubMed1994

Iron nutriture in elderly individuals.

The purpose of this review is to examine current research on the iron status of the elderly and factors that influence the body burden of iron. Studies of noninstitutionalized elderly individuals report mean iron intakes that meet current Recommended Dietary Allowances for iron. Dietary practices that may decrease iron bioavailability, and hence iron stores in the body, include low intakes of ascorbic acid or high intakes of calcium, and decreased consumption of highly available iron from meat, fish, and poultry. Although not well documented, the effect of age on iron absorption and iron excretion appears to be small, and body stores of iron increase with age. It is difficult to estimate the prevalence of iron deficiency in elderly persons, because impaired iron status can be the result of iron deficiency or chronic disease. Further study is necessary to determine whether red blood cell ferritin and serum transferrin receptors may be useful biochemical markers to differentiate the anemia of chronic disease from iron deficiency anemia. Hereditary hemochromatosis is a genetic disease that greatly increases the body burden of iron and the risk of hepatic disease among homozygotes. Because iron deficiency or iron excess may impair health, the role of iron in diseases associated with aging such as depressed immune response, neurological dysfunction, cancer, and heart disease is discussed.

Absorption↗
PubMed1992

Copper and selenium deficiencies do not enhance the cardiotoxicity in rats due to chronic doxorubicin treatment.

This study tests the hypothesis that Cu and Se deficiencies enhance doxorubicin-induced cardiotoxicity and anemia. Male Sprague-Dawley rats (n = 48) were fed Cu and Se-adequate (+Cu+Se), Cu-deficient (-Cu), Se-deficient (-Se) or Cu and Se-deficient (-Cu-Se) diets for 5.5 wk. Doxorubicin (4 mg/kg body wt) or saline was administered once weekly for the last 4 wk of the study. Copper deficiency was confirmed by 79% lower liver Cu, 67% lower liver Cu,Zn superoxide dismutase (Cu,Zn SOD) activity and 76% lower erythrocyte Cu,Zn SOD activity. Selenium deficiency was confirmed by 90% lower liver glutathione peroxidase activity. Rats fed the -Cu diet had greater reductions in hematocrit than did those fed the +Cu diet after administration of doxorubicin. Doxorubicin, Cu deficiency and Se deficiency all produced electrocardiographic abnormalities and ultrastructural anatomical lesions. However, the dietary deficiencies did not enhance doxorubicin-induced cardiotoxicity. Doxorubicin, but not Cu or Se deficiency, raised lipid peroxidation 16% in liver (P < 0.01) and 18% in heart (not significant). These data suggest that the cardiomyopathies caused by doxorubicin and Cu and Se deficiencies have some similarities, but cardiac changes may be related to mechanisms other than lipid peroxidation.

Animals↗
PubMedDate not supplied

Copper deficient rat heart can compensate for doxorubicin-induced oxidant stress.

The hypothesis that copper (Cu) alters drug metabolizing enzymes and functions as an antioxidant nutrient in doxorubicin cardiotoxicity was tested. Male Sprague-Dawley rats were fed Cu adequate (+Cu; 5 mg Cu/kg of diet), marginally Cu deficient (MCu; 1.2 mg Cu/kg of diet), or severely Cu deficient (-Cu; 0.5 mg Cu/kg of diet) diets for 6 wk. Doxorubicin (1, 2, or 4 mg/kg body wt) or saline were administered intraperitoneally 1 time/wk for 4 wk. Compared to control hearts, Cu,Zn superoxide dismutase activity was decreased by 9% in MCu rats and by 21-40% in -Cu rats. Glutathione peroxidase activity was elevated 5-15% in -Cu rats. Doxorubicin administration increased heart Cu,Zn superoxide dismutase activity in +Cu and -Cu rats 18 h after the last of 4 injections, but not 18 h after 1 injection. There was no synergism between doxorubicin and Cu deficiency on lipid peroxidation, plasma creatine phosphokinase, cardiac hypertrophy, electrocardiographic abnormalities, or morphological changes. Heart glutathione S-transferase activity was decreased by Cu deficiency, and like Cu,Zn superoxide dismutase activity, returned to normal in -Cu rats given doxorubicin. Thus, the Cu deficient rat heart may be able to compensate for doxorubicin-induced oxidant stress by increasing the activity of Cu,Zn superoxide dismutase and glutathione S-transferase.

Animals↗