Biomedical subjects

H K Biesalski

Publications and source records attributed to H K Biesalski.

At least 19 recordsLinked to original sources

PubMed2003

Carotenoids are decreased in biopsies from colorectal adenomas.

UNLABELLED: A lower intake of carotenoids is associated with an increased risk of colorectal cancer. In order to take advantage of the chemopreventive properties of carotenoids, it is necessary to determine carotenoid concentration at the target tissue. As early stages in the adenoma-carcinoma sequence of colorectal cancer might be susceptible to chemoprevention, we sought to determine carotenoid concentrations in biopsies from colorectal adenomas. METHODS: Biopsies from colorectal adenomas and non-involved mucosa were taken from seven patients. For controls, biopsies were obtained from the ascending and descending colon of patients without polyps (n = 5). Concentration of carotenoids (alpha-, beta-carotene, lutein, lycopene, zeaxanthin, beta-cryptoxanthin) were determined by optimizing gradient HPLC-analysis. Results are expressed as pmol/microg DNA. RESULTS: Except for alpha-carotene, all carotenoids could reliably be detected in all specimens. In control patients carotenoid concentrations were highest in the ascending colon, being followed by the descending colon and non-involved mucosa from polyp-carriers. In colorectal adenomas all carotenoids were significantly reduced as compared to-non-involved mucosa (beta-carotene: 0.37 vs 0.19, P<0.03; lycopene: 0.34 vs 0.21, P<0.06, beta-cryptoxanthin: 0.14 vs 0.09, P<0.03, zeaxanthin: 0.18 vs 0.09, P<0.02; lutein: 0.18 vs 0.13,P <0.02). CONCLUSION: All carotenoids investigated are reduced in colorectal adenomas, suggesting that mucosal carotenoids could serve as biomarkers for predisposition to colorectal cancer. Moreover, anti-tumor activity exerted by carotenoids is limited due to mucosal depletion. We speculate that supplementation of a larger array of carotenoids might be beneficial for patients with colorectal adenoma.

Adenoma↗

PubMed2003

Uptake of vitamin A in buccal mucosal cells after topical application of retinyl palmitate: a randomised, placebo-controlled and double-blind trial.

Retinoids have been reported to produce regressions in metaplastic changes of the mucosal epithelium. In order to define the role of these micronutrients in the prevention of squamous metaplasia of the oral cavity, it is necessary to measure their uptake in target tissues such as the buccal mucosal epithelium. We demonstrated in a trial that retinyl palmitate applied topically via a toothpaste is taken up by buccal mucosal cells in young healthy volunteers. In the randomised, parallel-designed, placebo-controlled and double-blind trial, forty volunteers divided in two groups cleaned their teeth either with a placebo toothpaste or a retinyl palmitate-containing toothpaste (1 mg/g) for 56 d. Buccal mucosal cells samples were taken from the healthy volunteers during the retinyl palmitate application and the following wash-out phase to determine the concentration of retinyl palmitate and retinol by HPLC. Supplementary blood samples were taken from the volunteers on days 0 and 56 to investigate changes in plasma retinyl palmitate and retinol concentrations. Results from only thirty participants (sixteen placebo and fourteen treated subjects) were used in the statistical evaluation as the remaining sample results were spoiled by a technical defect during the HPLC analysis. A significant (P<0.05) uptake of retinyl palmitate in buccal mucosal cells after 7 d and a significant (P<0.05) increase of plasma retinol after 17 d was demonstrated in our present study. The uptake of retinyl palmitate and the following hydrolysis to retinol led to an enrichment of vitamin A in buccal mucosal cells.

Absorption↗

PubMed2002

2-Methoxyestradiol enhances reactive oxygen species formation and increases the efficacy of oxygen radical generating tumor treatment.

In an investigation of the antitumor effects of 2-methoxyestradiol (2-ME) in combination with other reactive oxygen generating treatments, 2-ME (0.5 microM) was found to completely inhibit cell proliferation of rat DS-sarcoma cells in vitro, with 71% of cells dying after exposure to 5 microM 2-ME. Concentration-dependent increases in ROS-formation, lipid peroxidation and mitochondrial changes were also observed, and an elevation in caspase-3 activity resulted in DNA fragmentation and apoptosis. Combination of 2-ME with hypoxanthine and xanthine oxidase enhanced in vitro cytotoxicity. In vivo, 2-ME caused a slight inhibition of tumor growth, with no tumors cured. Combination of 2-ME treatment with localized 44 degrees C hyperthermia, respiratory hyperoxia and xanthine oxidase caused a tumor growth delay with 51% of tumors cured. These results suggest that amplifying the levels of reactive oxygen species within tumor tissue with substances such as 2-ME may prove to be a promising strategy for adjuvant treatment of solid tumors.

2-Methoxyestradiol↗

PubMed2002

Determination of vitamin A palmitate in buccal mucosal cells: a pilot study.

We report in our present pilot study on the uptake of retinyl palmitate and its formation to retinol in buccal mucosal cells. Retinoids are able to change metaplastic lesions in several tissues. Prior to any clinical evaluation it is necessary to measure its uptake in target tissues such as the buccal mucosal epithelium. In this pilot study 12 volunteers creamed the inside of their cheeks lightly with a 0.1% retinyl palmitate containing toothpaste for 10 days followed by a wash out phase. On day 0, 3, 7, 10, 17 and 21, buccal mucosal cell samples were taken from volunteers and the uptake of retinol and retinyl palmitate was determined by HPLC analysis. An uptake of vitamin A was demonstrated in all volunteers. Comparing day 0 to day 3 a significant uptake of retinyl palmitate (p<0.05) was detected and comparing day 3 to 17 and 21 a significant decrease (p<0.05) during growth and differentiation of the mucosal epithelium could be seen. The subsequently formed retinol showed an increase but no statistical significance was determined. - The uptake of retinyl palmitate and the formation to retinol led to an enrichment of vitamin A in buccal mucosal cells. In this way metaplastic alterations of the buccal mucosal epithelium might be prevented or reversed by the application of topical retinyl palmitate.

Adult↗

PubMed2002

Inhalation of aerosolized vitamin a: reversibility of metaplasia and dysplasia of human respiratory epithelia -- a prospective pilot study.

The objective of this preliminary uncontrolled study was twofold: First, to assess the feasibility of retinyl palmitate inhalation and second, to analyze the changes of metaplastic lesions of the respiratory epithelium (metaplasia or dysplasia) following retinyl palmitate inhalation. The response to a daily dose of 18.000 I.U. retinyl palmitate by inhalation over a period of 3 month was assessed in 11 subjects (9 smokers, 2 ex-smokers). Using white-light bronchoscopy combined with autofluorescence bronchoscopy, bronchial biopsies were taken before and after a 3 month-period. The biopsy samples were evaluated blind by a referee lung pathologist. The overall response rate (remission or partial remission) was 56% (95% CI 0.30 0.79; p<0.05). These data suggest that inhalation of retinyl esters could be a promising therapeutical approach for chemoprevention of lung cancer. Vitamin A; chemoprevention; lung cancer; squamous metaplasia; dysplasia; retinoids

Administration, Inhalation↗

PubMed2002

Hohenheim consensus workshop: copper.

Copper (Cu) is an essential trace element with many physiological functions. Homeostatic mechanisms exist to allow Cu to act as a cofactor in enzymatic processes and to prevent accumulation of Cu to toxic levels. The aim of this commentary is to better understand the role of dietary Cu supply in deficiency and under physiological and pathological conditions. The essentiality of Cu can be attributed to its role as a cofactor in a number of enzymes that are involved in the defence against oxidative stress. Cu, however, has a second face, that of a toxic compound as it is observed with accumulating evidence in hepatic, neurodegenerative and cardiovascular diseases. The destructive potential of Cu can be attributed to inherent physico-chemical properties. The main property is its ability to take part in Fenton-like reactions in which the highly reactive and extremely deleterious hydroxyl radical is formed. Diseases caused by dietary Cu overload could be based on a genetic predisposition. Thus, an assessment of risk-groups, such as infants with impaired mechanisms of Cu homeostasis regarding detoxification, is of special interest, as their Cu intake with resuspended formula milk may be very high. This implies the need for reliable diagnostic markers to determine the Cu status. These topics were introduced at the workshop by the participants followed by extensive group discussion. The consensus statements were agreed on by all members. One of the conclusions is that a re-assessment of published data is necessary and future research is required.

Cardiovascular Diseases↗

PubMed2002

Meat and cancer: meat as a component of a healthy diet.

Based on epidemiological studies it is assumed that meat, especially red meat, enhances risk for cancer, particularly of the colon, breast and prostate. Meat and meat products are important sources of protein, some micronutrients and fat. High fat intake has been blamed for correlation with different diseases, including cancer. Meat protein is reported to contribute to cancer formation. However, meat, including liver, is not only composed of fat and protein, it contains essential nutrients which appear exclusively in meat (vitamin A, vitamin B12) and micronutrients for which meat is the major source because of either high concentrations or better bioavailability (folate, selenium, zinc). In particular, vitamin A, folate and selenium are reported to be cancer-preventive, with respect to colon, breast and prostate cancer. Taken together, meat consists of a few, not clearly defined cancer-promoting and a lot of cancer-protecting factors. The latter can be optimized by a diet containing fruit and vegetables, which contain hundreds of more or less proven bioactive constituents, many of them showing antioxidative and anticarcinogenic effects in vitro.

Animals↗

PubMed2002

Long-term sequelae of HFE deletion in C57BL/6 x 129/O1a mice, an animal model for hereditary haemochromatosis.

BACKGROUND: HFE knockout mice (C57BL/6 x 129/Ola strain) mimic the functional aberrations of human hereditary haemochromatosis (HH) in short-term experiments. The present study investigates functional and morphological long-term changes. METHODS: HFE(o/o), HFE(+/o) and HFE(+/+) mice were maintained on iron-rich and control diets for 2 weeks, 3, 12 and 18 months. Light microscopic tissue iron distribution, pathomorphological alterations, tissue iron content and oxidative stress were analysed in liver, pancreas, spleen, gastrointestinal tract, kidneys and myocardium. Additionally, duodenal 59Fe absorption and 59Fe whole body loss were measured. RESULTS: Iron distribution between organs and microscopic iron deposition in the tissues resembled the patterns described in HH. After 3 months of iron-rich feeding duodenal 59Fe absorption decreased to approximately 15% of iron-adequate controls but remained about twice as high in HFE(o/o) as in HFE(+/+) mice. Hepatic iron concentrations reached only half the values known to induce hepatic fibrosis in rats and humans, while whole body 59Fe loss was about twice as high. Consequently no hepatic fibrosis developed, although massive hepatocellular iron deposition and indication for oxidative stress were observed. CONCLUSION: C57BL/6 x 129/O1a HFE(o/o) mice mimic HH iron distribution and the regulation of intestinal iron absorption after long-term feeding. However, characteristic morphological late changes in untreated HH are not modelled.

Animals↗

PubMed2002

Effects of RRR-alpha-tocopherol on leukocyte expression of HSP72 in response to exhaustive treadmill exercise.

Previous research revealed an increased expression of HSP72 in leukocytes after vigorous endurance exercise. We questioned whether more intensive but shorter exercise also induces leukocyte HSP72 synthesis. To delineate the role of reactive oxygen species (ROS) in exercise-related HSP72 induction, we additionally examined the effect of RRR-alpha-tocopherol (alpha-toc) on HSP72 expression using a double-blind placebo (P) controlled cross-over design. After supplementation with alpha-toc (500 I.U. daily) or P for 8 days, 9 male subjects performed a combined exhaustive treadmill protocol (total duration 29.4 +/- 2.0 min). HSP72 was assessed on mRNA (RT-PCR) and protein levels (flow cytometry). HSP72 mRNA rose 3 h after exercise only in the P group, but individual differences (alpha-toc - P) did not reveal significant treatment effects. A moderate but significant rise of HSP72 protein occurred in granulocytes up to 48 h after exercise. Three hours post-exercise, granulocyte HSP72 protein was lower when subjects received alpha-toc, but this effect vanished 24 and 48 h post-exercise. Exhaustive treadmill exercise augments HSP72 mRNA in leukocytes and induced a moderate but prolonged response of granulocyte HSP72 protein. These exercise effects are lower when compared to earlier findings obtained after vigorous endurance exercise. ROS seem to be involved, but do not play the major role in the induction of granulocyte HSP72 synthesis after exhaustive exercise.

Adult↗

PubMed2002

Nutrition and aging: a consensus statement.

OBJECTIVE: To consider the relationship between nutrition and aging. To summarize existing knowledge and identify areas of ignorance. DESIGN: Experts from a range of relevant disciplines received and considered a series of questions related to aspects of the topic. SETTING: University of Hohenheim, Stuttgart, Germany. INTERVENTION: The experts met and discussed the questions and arrived at a consensus. CONCLUSION: Many specific conclusions were drawn that support the general view that as we age an inadequate nutrition contributes to the loss of function and the development and progression of disease. Nutritional status is influenced by a range of medical, physiological, psychological, social and situational variables. Adequate nutrition and physical activity are aspects of a health-promoting lifestyle. The encouraging of better nutrition and the taking of exercise is a cost-effective way of decreasing the incidence and progression of age-related disease. The earlier such interventions are introduced the better.

Aged↗

PubMed2001

The effect of beta-carotene on the expression of interleukin-6 and heme oxygenase-1 in UV-irradiated human skin fibroblasts in vitro.

beta-Carotene is discussed as an anti-oxidant micronutrient and singlet oxygen quencher in human skin, protecting against UV light-induced damage. However, we recently demonstrated that beta-carotene has a pro-oxidant potential in cultured human skin fibroblasts because it enhances the UVA induction of heme oxygenase-1 (HO-1). Herein, we further show that beta-carotene also strongly promotes the UVA induction of pro-inflammatory interleukin-6 (IL-6) in skin fibroblasts in vitro. Singlet oxygen quencher sodium azide abrogated up-regulation of IL-6, and likewise also of HO-1. In UVB-irradiated cells, beta-carotene did not modulate levels of IL-6 and HO-1. The observed effects might be relevant for UV-induced inflammatory processes.

Child, Preschool↗

PubMed2001

Topical application of vitamin A reverses metaplasia of rat vaginal epithelium: a rapid and efficient approach to improve mucosal barrier function.

Retinyl palmitate and its metabolites retinol and retinoic acid control growth and epithelial differentiation. Systemic or local vitamin A deficiency induced by malnutrition, continuous chemical irritation or locally induced by inflammation causes squamous metaplastic changes in the epithelium of mucous membranes. We demonstrate that in an animal model topically applied retinyl palmitate can be taken up by the mucosal cells independently from the systemic supply. Under in vivo conditions metabolic changes in vaginal epithelium of rats were shown to be reversed by treatment with topical retinyl palmitate. - After only two days treatment squamous metaplastic vaginal epithelium in rats shows a reversal of the epithelium into a normal phenotype which continues after cessation of the treatment for 7 to 11 days. Higher concentrations and longer retention times lead to a statistically significant (p = 0.025) increase in the protection time. These data demonstrate that squamous changes induced by vitamin A deficiency can be totally reversed with topically applied retinyl palmitate.

Administration, Topical↗

PubMed2001

A modified system to evaluate the potency of anti-oxidative compounds in different cell types in vitro.

Common assays for evaluation of antioxidative capacity of different compounds are usually performed in cell-free systems. By this approach, cell-specific regulatory mechanisms upon distinct stimuli are not taken into account. Therefore, there is a need to measure anti-oxidative capacity in a cellular setting. - We now developed a valid method that provides monitoring of anti-oxidative capacities of compounds in different cell types. Oxidative stress, induced by 100 microM H subset2O subset2 in human microvascular endothelial cells (HMEC-1), was quantified by the generation of oxidized, fluorescent C-DCF from C-H subset2DCF-DA/AM. As DCF-production could be almost completely blocked by diethyldithiocarbamate (DEDTC), which inhibits intracellular Cu/Zn superoxide dismutase (SOD), mainly intracellular production of C-DCF was assumed. Preincubation with alpha-tocopherol resulted in a dose-dependent reduction of both spontaneous and H subset2O subset2-induced C-DCF-production (maximal inhibition by 41.6% at 75 microM). A synergistic effect was observed with co-incubation with vitamin C (maximal inhibition 46.8% at 10 microM vitamin C and 50 microM alpha-tocopherol). In this way compounds with different modes of action and subcellular localization can be evaluated concomitantly in respect of their anti-oxidative capacities. As this method was established on 24- and 48-well plates in other cell lines (Caco-2, HFP-1), too, screening of a large array of antioxidative compounds in different cell lines can be performed.

Antioxidants↗

PubMed2001

UV light, beta-carotene and human skin--beneficial and potentially harmful effects.

Solar radiation is one of the most important environmental stress agents for human skin, causing sunburn, premature skin aging, and skin cancer. Beta-carotene is discussed to protect against photooxidative stress and thus prevent skin damage. Though beta-carotene has been successfully used against photosensitivity in patients with erythropoietic protoporphyria, its beneficial potential in normal skin is still uncertain. A number of experimental studies indicate protective effects of beta-carotene against acute and chronic manifestations of skin photodamage. However, most clinical studies have failed to convincingly demonstrate its beneficial effects so far. Nevertheless, intake of oral beta-carotene supplements before sun exposure has been recommended on a population-wide basis. Recent studies on skin cells in culture have revealed that beta-carotene acts not only as an antioxidant but also has unexpected prooxidant properties. At present, there is an ongoing debate on the protective or potentially harmful role of beta-carotene in human skin.

Fibroblasts↗

PubMed2001

[Vitamin A metabolism and retinal degeneration].

Vitamin A plays an important role in the pathogenesis and during the course of retinal degenerations. Following a brief overview of the metabolic pathway of Vitamin A from the entrance into the body to the arrival in retinal target structures, the most important retinal degenerations that are related to the Vitamin A-metabolism are presented. Ways of prevention or therapy of such diseases are discussed in the light of the still incomplete knowledge about basic mechanisms of retinol transport and metabolism.

Humans↗

PubMed2001

Dietary intake and nutritional status of women and pre-school children in the Republic of the Maldives.

OBJECTIVE: Malnutrition and poor nutritional status among children are common problems in the Republic of Maldives, a small island nation in the Indian Ocean. The aim of this study was to determine possible macro- and micronutrient deficiencies in the traditional Maldivian diet. DESIGN: In five atolls, 333 women with children aged between 1 and 4 years who were no longer breast-fed were interviewed, using a 24-hour recall. Additionally, the weights and heights of both the women and children were measured, and blood samples from 15 women were collected for measurements of vitamins A and E, beta-carotene, homocysteine, cholesterol and haemoglobin. RESULTS: Of the women, 22% had a body mass index (BMI) below 18.5. Of the children, 41% were stunted, 14% were wasted and 51% were underweight. The women's and children's diets were sufficient in protein (14%) and carbohydrates (67%) but deficient in fat, which contributed only 19% to the total energy intake. Consumption of dietary substances that depend on vegetable and fruit intake (e.g. beta-carotene, vitamin C, dietary fibre and folic acid) was low. The low intake of beta-carotene was underlined by low plasma concentration. The estimated iron intake was low, although blood haemoglobin levels were normal. CONCLUSIONS: Marginal nutritional status and marginal malnutrition are due to low fat intake and selected micronutrient deficiency. Higher intakes of locally available vegetables and fruits and fat (especially for children) on a regular basis might reverse the deficits documented on the atolls.

Adult↗

PubMed2001

Protective effects of vitamins C and E on the number of micronuclei in lymphocytes in smokers and their role in ascorbate free radical formation in plasma.

Cigarette smoke is widely believed to increase free radical concentrations causing subsequent oxidative processes that lead to DNA damage and hence, to several diseases including lung cancer and atherosclerosis. Vitamin C is a reducing agent that can terminate free-radical-driven oxidation by being converted to a resonance-stabilized free radical. To investigate whether short-term supplementation with the antioxidants vitamin C and E decreases free-radical-driven oxidation and thus decreases DNA damage in smokers, we determined the frequency of micronuclei in lymphocytes in 24 subjects and monitored the electron paramagnetic resonance signal of ascorbate free radical formation in plasma. Further parameters comprised sister-chromatid exchanges and thiobarbituric acid-reactive substances. Twelve smokers and twelve non-smokers took 1000 mg ascorbic acid daily for 7 days and then 1000 mg ascorbic acid and 335.5 mg RRR-alpha-tocopherol daily for the next 7 days. Baseline concentrations of both vitamins C and E were lower and baseline numbers of micronuclei were higher (p < 0.0001) in smokers than in non-smokers. After 7 days of vitamins C and E, DNA damage as monitored by the number of micronulei was decreased in both, smokers and non-smokers, but it was more decreased in smokers as indicated by fewer micronuclei in peripheral lymphocytes (p < 0.05). Concomitantly, the plasma concentrations of vitamin C (p < 0.001) as well as the ascorbate free radical (p < 0.05) were increased. The corresponding values in non-smokers, however, did not change. Our findings show that increased ascorbate free radical formation in plasma after short-term supplementation with vitamins C and E can decrease the number of micronuclei in blood lymphocytes and thus DNA damage in smokers.

Adult↗

PubMed2001

Measurement of ferritin levels: comparison of a commercial IRMA to an in-house ELISA method.

The purpose of this study was a comparison of a commercial IRMA to an in-house ELISA method. Because IRMA methods are considered to be very sensitive and results of these assays are widely accepted, the ferritin levels of 378 school children were determined in parallel with a commercial IRMA kit (Becton Dickinson Co., Orangeburg, NY) and the ELISA. For organizing reasons plasma was used for the ELISA, whereas serum was used for the IRMA. Regression analysis of the pairs of values, taking the IRMA reading as the independent variable, yielded a coefficient of variation r=0,90 (Spearman, two-tailed, p=0,01) and the straight line y=0,99x+3,13. Using this ELISA technique described by DAKO, ferritin levels in plasma were, on average, 13,2% higher than in serum taken at the same time. The ELISA technique described was found to have good accuracy and the speed and ease with which it may be carried out makes it suitable for a large number of samples.

Child↗