Biomedical subjects
B Borch-Iohnsen
Publications and source records attributed to B Borch-Iohnsen.
The effect of daily low-dose iron supplements in female blood donors with depleted iron stores: comparison with female non-donors.
Female blood donors with serum ferritin < or = 20 micrograms l-1 and haemoglobin > 120 g l-1 participated in an iron supplement study with two different low-dose supplements in a period without donations. Comparable non-donors served as controls. Serum ferritin, haemoglobin and transferrin were determined. Increases in serum ferritin and in haemoglobin, and decrease in transferrin were highly significant (p < 0.01) in both donor groups. In one of the non-donor groups the increase in serum ferritin and decrease in transferrin were highly significant (p < 0.01), while in the other only transferrin changed significantly (p < 0.03). The increases in serum ferritin and haemoglobin over a 5-month period were significantly higher among donors (p < 0.001) than among non-donors. We interpret the results to mean that the donors have a more efficient iron absorption.
Seasonal siderosis in female eider nesting in Svalbard.
Specimens of female and male eider (Somateria mollissima) were collected in Svalbard. Atomic absorption analyses revealed mean hepatic iron concentrations of 280 micrograms per g wet weight 2 to 3 weeks before egg laying, 2620 micrograms per g after 2 to 3 weeks brooding and 800 micrograms per g 2 weeks after hatching. At the highest concentration, there was massive siderosis with the iron located in both parenchymal and non-parenchymal cells. No signs of liver injury were seen. The female eider fasts completely from the start of egg laying to the end of hatching. The non-parenchymal iron deposits are probably the result of catabolism of blood and lean tissue, i.e., translocation of body iron. The parenchymal siderosis can hardly be explained by liver weight loss alone. An increased iron absorption preceding the egg laying is suggested.
[Iron status in blood donors evaluated by serum ferritin].
In the present study we have examined serum ferritin in experienced male and female blood donors and in women who had never donated blood before, but had registered at the Blood Centre as future donors. There was no coincidence between low haemoglobin and low s-ferritin when haemoglobin was within normal range. Iron stores (s-ferritin less than 20 micrograms/l) were reduced in 40% of the female blood donors and in 21% the iron stores (s-ferritin less than 10 micrograms/l were completely empty. 10% of the male donors had iron stores, while in 3% the iron stores were empty. Among the females who had not donated blood, 30% had s-ferritin values below 20 micrograms/l and 6% had values below 10 micrograms/l. We conclude that measuring s-ferritin is a better method of identifying individuals at risk for iron depletion than measuring hemoglobins. A combination of longer intervals between donations and iron therapy may prevent depletion of iron stores in blood donors.
[Iron and sports].
We review normal iron metabolism and iron deficiency in athletes with and without anemia, and possible causal relationships. Hard physical training, such as medium and long distance running, appears to promote negative iron balance, with and without fall in hemoglobin concentration. A normally varied diet is suggested as adequate to meet the iron requirements in male athletes. Iron supplementation is not recommended unless blood/serum concentration of hemoglobin, ferritin, iron and transferrin are measured and the results indicate a state of iron deficiency. However, female athletes should consider iron supplementation, since loss of iron is higher in women than in men.
Chemical and morphological studies of liver from eider (Somateria mollissima) in Svalbard with special reference to the distribution of copper.
Specimens of male and brooding female eider (Somateria mollissima) were collected in Svalbard. Chemical analyses revealed hepatic copper concentrations ranging from 20 to 1050 micrograms per g wet weight. This is in agreement with previous results. The selenium, zinc and cadmium values were equal to or slightly higher than previously recorded. It is suggested that the wide variation in copper concentration is a result of differences in intake of copper-containing food among the birds. High selenium intake may enhance copper accumulation. Starvation influences the concentration of zinc and also copper. Zinc concentrations were significantly higher in females. This may be secondary to starvation. The percentage of copper recovered among the soluble proteins was inversely related to the copper content. The distribution of the soluble proteins reflects a normal copper metabolism. Microscopic studies showed prominent dark granules, positive with the rubeanic acid test for copper, confined to hepatocytes. By electron microscopy, the granules appeared as large irregular, electron-dense bodies that, by X-ray microanalysis, were found to contain copper. There were no signs of liver injuries such as necrosis and fibrosis. Apparently, the eider has evolved a high capacity for copper storage.
Hypoxia and deposition of iron in liver and spleen of mice given iron supplement.
Iron-related changes in peripheral blood and variations in liver and spleen iron concentrations during alternating periods of hypoxia and normoxia have been investigated in iron-supplemented mice by chemical and histological methods. During hypoxia, packed cell volume increased from 40 to 70%. The iron content of the liver increased during the first hypoxic and the following normoxic period, while an increase in spleen iron started after the first hypoxic period. Transferrin saturation fell from about 60 to about 20% during hypoxia and normalized during normoxia. Hypoxia together with iron supplementation led to increased erythropoiesis and parenchymal iron deposition in liver. The reduction in transferrin saturation may be attributed to the effective uptake of iron by hepatocytes simultaneously with the erythropoiesis. The spleen seemed to participate in the production of red cells during hypoxia. The increase in spleen iron during normoxia can be explained by the role of the spleen in the catabolism of excess erythrocytes.
Iron status in a group of Norwegian menstruating women.
Serum ferritin was determined in 170 healthy Norwegian women (18-48 years; median age 36 years) including 23 blood donors. In women with serum ferritin less than or equal to 20 micrograms/l haemoglobin, serum iron and total iron binding capacity were determined. Women using oral contraceptives were excluded. Information was collected on use of contraceptive techniques, habits of iron prophylaxis, and duration of menses. About 40 per cent of the participants used the intra-uterine device. Geometric mean serum ferritin was 26.9 micrograms/l with a prevalence of 21.8 per cent with exhausted iron stores (serum ferritin less than 17 micrograms/l) among the non-donors. In the group with low to empty iron stores (serum ferritin less than or equal to 20 micrograms/l) 13 per cent had anaemia (Hb less than 120 g/l). This may correspond to 4.1 per cent among all the non-donors. The blood donors had a geometric mean serum ferritin of 20.4 micrograms/l and 30 per cent with empty stores. Our study shows that in the group of non-donors there was a tendency to higher prevalence of low or empty iron stores among IUD-users and premenopausal women. In addition to these groups the blood donors are at risk of iron deficiency.
Bioavailability of daily low dose iron supplements in menstruating women with low iron stores.
Women (n = 45; 18-48 years) with serum ferritin less than or equal to 20 micrograms/l and haemoglobin greater than 120 g/l participated in an iron supplement bioavailability study. They were randomized to one of three groups and given one of three different low-dose supplements (18-20 mg iron/d) for 6 months. One of the supplements contained haem iron and non-haem iron, the others contained non-haem iron only. Serum ferritin, haemoglobin, serum iron and total iron binding capacity (TIBC) were determined at start and after 1, 3 and 6 months. Dietary intakes were recorded during 4 and 3 consecutive days after 1 and 3 months, respectively, by the aid of household measures and a set of food models. The increase in mean serum ferritin was significant (P less than 0.01) for two of the supplements, the one containing haem iron giving the best result. All the supplements resulted in a significant (P less than 0.011) mean decrease in TIBC. No significant differences between the groups were found in daily intakes of food factors known to influence iron absorption. The improvement in iron status was therefore attributed to the supplements. None of the supplements caused iron intolerance. Thus low-dose iron supplements given to iron depleted non-anaemic women may be an alternative to high-dose therapy.
[Women and iron deficiency--a problem? Iron levels in a group of fertile Norwegian women and the bioavailability of 3 low-dose iron supplements in women with low iron stores].
Serum ferritin levels were determined in 170 healthy Norwegian women (18-48 y, median age 36 y) including 23 blood donors. Exhausted iron stores, defined by serum ferritin levels less than 17 micrograms/l, were found in 21.8% of the non-donors, and in 30.4% of the donors. Women with serum ferritin levels less than or equal to 20 micrograms/l participated in a bioavailability study. They were randomized to one of three groups and given one of three different low dose iron supplements (18-20 mg iron per day) for six months. One of the supplements contained heme iron and non-heme iron, the other two contained non-heme iron only. Mean serum ferritin increase was significant for two of the supplements, the one containing heme iron giving the best result. All the supplements resulted in a significant decrease in TIBC.
Oxidative capacity of tissues contributing to thermogenesis in eider (Somateria mollissima) ducklings: changes associated with hatching.
1. The development of liver and skeletal muscle oxidative capacities during hatching of the common eider (Somateria mollissima) in the Arctic has been investigated by monitoring tissue cytochrome c oxidase activity. 2. The specific activity of the liver enzyme did not change as the embryo underwent hatching, nor during subsequent growth of the duckling into adulthood. 3. Thigh muscle enzyme specific activity increased by a factor of 3.4 during the 24 h prehatching period, remained elevated for at least 48 h after hatching, and then returned to the embryonic (-24 h) level in adults. 4. Histochemically visualized NADH-tetrazolium reductase of a typical red thigh muscle, M. vastus lateralis, showed a distinct increase in activity as the hatching process progressed to completion. 5. Electron microscopy of sectioned M. vastus lateralis revealed a dramatic increase in the density of the myofibrillar structure (number of mitochondrial profiles per unit area), and in the surface area of mitochondrial crista membranes in the course of the 48 h interval from 1 day prehatching to 1 day after hatching. 6. The significance of these changes for the scaling of thermoregulatory heat generation in the newly hatched eider duckling is discussed.
Seasonal variation in the form of iron in the liver of Spitsbergen reindeer: a Mössbauer spectroscopic study.
Mössbauer spectra have been obtained from samples of the liver of Spitsbergen reindeer at different times of the year. Most of the iron is in a very similar form to that of the iron storage materials ferritin and haemosiderin. The data reflect the large differences in the amount of iron found in the liver at different times of the year and also indicate that there are only relatively small differences in the chemical and physical form of the iron found in the liver at different times of the year.
Seasonal iron overload in Svalbard reindeer liver.
Changes in liver iron concentration in relation to seasonal body weight variations and food iron intake have been investigated in 77 Svalbard reindeer by chemical and histological methods. During the winter season the body weight decreased about 43% in females and 39% in males. Liver weight was reduced about 65% in both sexes. The liver iron concentration showed little or no difference between the sexes and was 29 +/- 13 mg iron/100 g wet weight in the autumn. The concentration increased in late winter to 291 +/- 52 mg iron/100 g in animals eating iron-rich forage plants, and to 165 +/- 92 mg iron/100 g in animals eating forage plants with a normal iron content. Starving animals with a very high iron concentration of the rumen content usually had massive siderosis in both parenchymal and nonparenchymal cells of the liver. In contrast, siderosis was restricted to nonparenchymal cells in starving animals with normal rumen iron concentration. Transferrin saturation was significantly higher in animals eating iron-rich forage plants than in those eating forage plants with a normal content. Therefore it is proposed that seasonal liver siderosis is a result of a) translocation of iron from catabolized blood and lean tissue that is recovered in nonparenchymal cells and b) high uptake of food iron with deposition in the parenchymal cells.