Biomedical subjects

Marianne Hansen

Publications and source records attributed to Marianne Hansen.

9 recordsLinked to original sources

PubMed2006

Uptake and speciation of selenium in garlic cultivated in soil amended with symbiotic fungi (mycorrhiza) and selenate.

The scope of the work was to investigate the influence of selenate fertilisation and the addition of symbiotic fungi (mycorrhiza) to soil on selenium and selenium species concentrations in garlic. The selenium species were extracted from garlic cultivated in experimental plots by proteolytic enzymes, which ensured liberation of selenium species contained in peptides or proteins. Separate extractions using an aqueous solution of enzyme-deactivating hydroxylamine hydrochloride counteracted the possible degradation of labile selenium species by enzymes (such as alliinase) that occur naturally in garlic. The selenium content in garlic, which was analysed by ICP-MS, showed that addition of mycorrhiza to the natural soil increased the selenium uptake by garlic tenfold to 15 microg g(-1) (dry mass). Fertilisation with selenate and addition of mycorrhiza strongly increased the selenium content in garlic to around one part per thousand. The parallel analysis of the sample extracts by cation exchange and reversed-phase HPLC with ICP-MS detection showed that gamma-glutamyl-Se-methyl-selenocysteine amounted to 2/3, whereas methylselenocysteine, selenomethionine and selenate each amounted to a few percent of the total chromatographed selenium in all garlic samples. Se-allyl-selenocysteine and Se-propyl-selenocysteine, which are selenium analogues of biologically active sulfur-containing amino acids known to occur in garlic, were searched for but not detected in any of the extracts. The amendment of soil by mycorrhiza and/or by selenate increased the content of selenium but not the distribution of detected selenium species in garlic. Finally, the use of two-dimensional HPLC (size exclusion followed by reversed-phase) allowed the structural characterisation of gamma-glutamyl-Se-methyl-selenocysteine and gamma-glutamyl-Se-methyl-selenomethionine in isolated chromatographic fractions by quadrupole time-of-flight mass spectrometry.

Enzymes↗

PubMed2006

[Refractory anaemia successfully treated with thalidomide].

A 63-year-old male was admitted to our department in 2001 because of autoimmune haemolytic anaemia and splenomegaly. Bone marrow examination revealed an erythroid hyperplasia and a normal chromosome analysis. Splenectomy was performed in 2002, resulting in severe transfusion-dependent anaemia with a need for two blood transfusions each week. Treatment with prednisolone, erythropoietin and danocrine was without effect. A new bone marrow examination then showed myelodysplastic syndrome. Treatment with thalidomide, 50-150 mg/d, and prednisolone, 25 mg/d, resulted in an increase in haemoglobin to 8.9 mmol/l during the following months. The use of immunomodulatory and anti-angiogenetic agents in refractory anaemia needs more study.

Anemia, Refractory↗

PubMed2004

Determination of inorganic arsenic in white fish using microwave-assisted alkaline alcoholic sample dissolution and HPLC-ICP-MS.

An analytical method for the determination of inorganic arsenic in fish samples using HPLC-ICP-MS has been developed. The fresh homogenised sample was subjected to microwave-assisted dissolution by sodium hydroxide in ethanol, which dissolved the sample and quantitatively oxidised arsenite (As(III)) to arsenate (As(V)). This allowed for the determination of inorganic arsenic as a single species, i.e. As(V), by anion-exchange HPLC-ICP-MS. The completeness of the oxidation was verified by recovery of As(V) which was added to the samples as As(III) prior to the dissolution procedure. The full recovery of As(V) at 104 +/- 7% (n = 5) indicated good analytical accuracy. The uncertified inorganic arsenic content in the certified reference material TORT-2 was 0.186 +/- 0.014 ng g(-1) (n = 6). The method was employed for the determination of total arsenic and inorganic arsenic in 60 fish samples including salmon from fresh and saline waters and in plaice. The majority of the results for inorganic arsenic were lower than the LOD of 3 ng g(-1), which corresponded to less than one per thousand of the total arsenic content in the fish samples. For mackerel, however, the recovery of As(III) was incomplete and the method was not suited for this fat-rich fish.

Alcohols↗

PubMed2004

A decrease in iron status in young healthy women after long-term daily consumption of the recommended intake of fibre-rich wheat bread.

BACKGROUND: Fibrerich bread and cereals are included in the recommendations of a healthy diet. OBJECTIVE: To measure the effects of long-term consumption of the recommended intake of fibre-rich wheat bread on the iron status of young healthy women with adequate iron stores. DESIGN: Four-months intervention study including healthy female subjects assigned into two groups provided daily with 300 g of fibre-rich wheat bread, prepared with or without phytase as a supplement to their habitual diet. SUBJECTS: Forty-one women aged 24.8 +/- 3.8 years (mean +/- SD) and an average BMI of 22.0 +/- 2.9 kg/m2 participated. Baseline values for serum ferritin were 45 microg/L, 22-83 (geometric mean, range) and for haemoglobin 132 g/L, 119-148 (arithmetic mean, range), respectively. RESULTS: Distribution of energy intake from protein, fat and carbohydrate, and daily intake of dietary fibre and iron were similar in the two groups and within the recommended levels. There was no effect of the phytase added to the wheat bread on the iron status of the subjects, but an effect of the intervention period. Serum ferritin and haemoglobin levels were significantly reduced by 12 +/- 1.1 microg/L (27%) (P < 0.001) and 2 +/- 0.8 g/l (1.5%) (mean +/- SE) (P < 0.05) respectively, after four months of intervention. CONCLUSIONS: The present long-term study indicates that consumption of the recommended daily intake of fibre-rich wheat bread results in an impairment of iron status in women with initially sufficient iron stores. Reduction of the phytic acid concentration in the bread was not sufficient to maintain iron status.

Adult↗

PubMed2004

Calcium from milk or calcium-fortified foods does not inhibit nonheme-iron absorption from a whole diet consumed over a 4-d period.

BACKGROUND: Single-meal studies have indicated that calcium inhibits iron absorption in humans. However, numerous dietary factors influence iron absorption, and the effect of calcium may not be as pronounced when calcium is served as part of a whole diet. OBJECTIVE: We investigated the effect of 3 sources of calcium served with the 3 main meals on nonheme-iron absorption from a 4-d diet. DESIGN: (59)Fe absorption was estimated from whole-body retention measurements in 14 women aged 21-34 y, each of whom consumed four 4-d diets in a randomized crossover design. The diets differed in the source of calcium as follows: a basic diet (BD) with a low content of calcium (224 mg Ca/d), a BD with a glass of milk served at each meal (826 mg Ca/d), a BD with calcium lactate (802 mg Ca/d), and a BD with a milk mineral isolate containing calcium (801 mg Ca/d). The 2 latter calcium sources were added to selected foods of the BD (rye bread, white bread, chocolate cake, and orange juice), and these foods were consumed with the 3 meals. All diets provided 13.2 mg Fe/d. RESULTS: No significant differences in nonheme-iron absorption were found between the BD and the BD supplemented with milk, calcium lactate, or the milk mineral isolate [7.4% (95% CI: 5.3%, 10.5%), 5.2% (3.5%, 7.9%), 6.7% (5.0%, 8.9%), and 5.1% (3.2%, 7.9%), respectively; P = 0.34]. CONCLUSION: Consumption of a glass of milk with the 3 main meals or of an equivalent amount of calcium from fortified foods does not decrease nonheme-iron absorption from a 4-d diet.

Adult↗

PubMed2003

Nonheme-iron absorption from a phytate-rich meal is increased by the addition of small amounts of pork meat.

BACKGROUND: Muscle tissue from various sources is known to promote nonheme-iron absorption. However, systematic studies of the dose dependency of this effect of meat on iron absorption from an inhibitory meal with low amounts of meat are lacking. OBJECTIVE: We investigated the dose-response effect of small amounts of meat on nonheme-iron absorption from a meal presumed to have low iron bioavailability. DESIGN: Forty-five healthy women with a mean (+/-SD) age of 24 +/- 3 y were randomly assigned to 1 of 3 groups, each of which was served (A) a basic meal (rice, tomato sauce, pea purée, and a wheat roll) and (B) the basic meal with either 25, 50, or 75 g pork (longissimus muscle). Meal A contained 2.3 mg nonheme iron, 7.4 mg vitamin C, and 220 mg (358 micro mol) phytate. Each meal was served twice, and the order of the meals was ABBA or BAAB. The meals were extrinsically labeled with (55)Fe or (59)Fe. Iron absorption was determined from measurements of (59)Fe whole-body retention and the activity of (55)Fe and (59)Fe in blood samples. RESULTS: Twenty-five grams meat did not increase nonheme-iron absorption significantly (P = 0.13), whereas absorption increased 44% (P < 0.001) and 57% (P < 0.001), respectively, when 50 and 75 g meat were added to the basic meal. In absolute values, this corresponds to an absorption that was 2.6% and 3.4% higher, respectively, than that with the basic meal after adjustment of the data to a level of 40% absorption from a reference dose. CONCLUSION: Small amounts of meat (>or=50 g) significantly increase nonheme-iron absorption from a phytate-rich meal low in vitamin C.

Adult↗

PubMed2003

A novel dual radio- and stable-isotope method for measuring calcium absorption in humans: comparison with the whole-body radioisotope retention method.

BACKGROUND: Dietary calcium absorption can be determined only with the use of isotope techniques. Currently used isotope techniques require exclusive equipment or are not true tracer approaches. OBJECTIVE: The objective was to compare a dual-isotope method combining radioisotopes and stable isotopes with a whole-body radioisotope retention method for measuring calcium absorption. DESIGN: Seven healthy adults aged 21-27 y consumed a test meal containing 63 +/- 14 (macro x +/- SD) mg Ca together with a water solution of (47)Ca (0.11 MBq). One hour after ingestion, 18 mg (44)Ca was administered intravenously. All feces and urine were collected for 5 and 6 d, respectively. Calcium absorption was estimated from whole-body retention of the radioisotope 12 times over 3 wk after ingestion and from the excretion of (47)Ca and (44)Ca in a 24-h urine sample collected on day 2. (44)Ca in urine was determined by inductively coupled plasma mass spectrometry. RESULTS: Mean (+/- SD) calcium absorption was 75 +/- 9% with the dual-isotope method and was 74 +/- 8% with the whole-body radioisotope retention method. There was a high degree of agreement between the methods. CONCLUSION: The dual-isotope method is a valid approach for measuring calcium absorption from a single meal.

Administration, Oral↗

PubMed2003

Increasing the cooking temperature of meat does not affect nonheme iron absorption from a phytate-rich meal in women.

The effect of increasing cooking temperatures of meat on nonheme iron absorption from a composite meal was investigated. Cysteine-containing peptides may have a role in the iron absorption enhancing effect of muscle proteins. Heat treatment can change the content of sulfhydryl groups produced from cysteine and thereby affect iron absorption. Twenty-one women (25 +/- 3 y) were served a basic meal without meat and two other meals consisting of the basic meal plus 75 g of pork meat cooked at 70, 95 or 120 degrees C. The meals were extrinsically labeled with (55)Fe or (59)Fe. Iron absorption was determined from measurements of whole-body (59)Fe retention and the activity of (55)Fe and (59)Fe in blood samples. Nonheme iron absorptions were 0.9 (0.5-4.0)% (P = 0.06), 0.7 (0.4-3.9)% (P = 0.1) and 2.0 (1.3-3.1)% (P < 0.001) greater when meat cooked at 70, 95 or 120 degrees C, respectively, was added to the basic meal. Increasing the cooking temperature of meat did not impair nonheme iron absorption compared with cooking at 70 degrees C. Because the cysteine content of meat decreased with increasing cooking temperature, this argues against a specific contribution of sulfhydryl groups from cysteine residues in the promotion of nonheme iron absorption by meat proteins.

Adult↗

PubMedDate not supplied

Speciation and bioavailability of selenium in yeast-based intervention agents used in cancer chemoprevention studies.

This study investigated the speciation and bioavailability of selenium in yeast-based intervention agents from multiple manufacturers from several time points. Sources of selenized yeast included Nutrition 21 (San Diego, CA), which supplied the Nutritional Prevention of Cancer (NPC) Trial from 1981-1996; Cypress Systems (Fresno, CA; 1997-1999); and Pharma Nord (Vejle, Denmark; 1999-2000), which supplied the Prevention of Cancer by Intervention by Selenium (PRECISE) Trial pilot studies. The low-molecular-selenium species were liberated from the samples by proteolytic hydrolysis followed by separation by ion exchange liquid chromatography and detection by inductively coupled plasma-mass spectrometry. The results for the NPC tablets showed that selenomethionine, together with 3 unidentified selenium compounds, were predominant in the sample hydrolysates. The relative amounts of the 4 selenium species varied (p < 0.05) among several of the 7 tablet batches used during the course of the NPC Trial. In comparison, 5 batches of more recently produced selenized yeasts, which were used as a source of selenium in the PRECISE and other trials, contained less of the unknown compounds and more selenomethionine at 54-60% of the total selenium in the yeasts. One batch of yeast, however (from 1985), which originated from the same producer as the yeast used in the NPC tablets, contained only 27% of selenium in the sample as selenomethionine. Human subjects receiving 200 microg selenium/day in the UK PRECISE Pilot Trial showed a higher concentration (p < 0.01) and higher increase from baseline in plasma selenium than did the same dosage used in the NPC Trial. Differences in intake, speciation, or bioavailability of selenium from the yeast-based supplements in the population groups studied may explain this. Furthermore, the selenium concentration in whole blood from the Danish PRECISE Pilot Trial was higher (p < 0.001) than that obtained with synthetic L-selenomethionine in a comparable group of Danes, both groups having been treated with 300 microg selenium/day.

Anticarcinogenic Agents↗