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Biomedical subjects

E Björn-Rasmussen

Publications and source records attributed to E Björn-Rasmussen.

At least 19 recordsLinked to original sources
PubMed1989

Biliary excretion of iron and ferritin in idiopathic hemochromatosis.

The role of biliary excretion of iron and ferritin in iron overload was studied and evaluated. Ten patients with idiopathic hemochromatosis and two groups of controls (14 gallstone patients and 16 healthy subjects) were included. Liver tissue (obtained by percutaneous or operative biopsy) was investigated with light microscopy and transmission electron microscopy in combination with x-ray microanalysis. Fasting bile samples were obtained through duodenal aspiration or at cholecystectomy. Iron was determined in liver tissue and bile using atomic absorption spectroscopy, and ferritin was determined in serum and bile with a radioimmunoassay technique. All patients with hemochromatosis had iron-positive staining as seen in light microscopy. Electron microscopy showed iron-containing proteins in the lysosomes and cytosol of liver parenchymal cells, and this observation was supported by x-ray microanalysis. Hepatic iron concentration was increased about eightfold in the patients with hemochromatosis (p less than 0.001). Biliary iron concentration, expressed per millimole of bile acid, was increased about twofold (p less than 0.05) and biliary ferritin concentration about fivefold (p less than 0.001) in hemochromatosis. Four of the patients with hemochromatosis were reexamined after completed treatment with venesection; this resulted in normalized biliary concentrations of iron and ferritin. We conclude that biliary secretion of ferritin occurs in humans and that both iron and ferritin excretion are enhanced in hepatic iron overload. The apparently limited capacity of biliary iron excretion may be of importance for the hepatic iron accumulation in hemochromatosis.

Adult↗
PubMed1989

Prevalence of hereditary haemochromatosis in two Swedish urban areas.

The prevalence of hereditary haemochromatosis (HH) was studied in Stockholm and Göteborg, the two largest cities in Sweden, using screening with transferrin saturation in combination with serum ferritin and further clinical and laboratory examinations. In Göteborg, none of 1660 men aged 50 and 51 years, randomly selected from the census register, was found to have HH. In Stockholm, nine out of 11,920 male hospital inpatients were diagnosed as having HH. The calculated mean and 95% confidence ranges were consistent with earlier findings in two studies on men in Malmö, the third largest urban area in Sweden. Pooling results from these three main urban areas, the mean prevalence was 0.073% (17/23, 355), which is considerably lower than figures reported from one area in northern Sweden and from pedigree analyses in several other areas in the world. Screening of the US population in the N-HANES II study also showed much lower figures. The reasons for these discrepancies are discussed and it is suggested that the average prevalence of HH in Caucasian populations is probably around 0.1%.

Hemochromatosis↗
PubMed1986

Monocyte chemotactic properties in hereditary hemochromatosis.

Several observations indicate that the innate metabolic defect in hereditary hemochromatosis (HH) leads to a defective function of the monocyte-macrophage system. The present study was performed to investigate the possibility that a defect in migration of cells of the monocyte-macrophage system can explain the abnormal location of the submucosal macrophages in HH. Monocytes isolated from 14 patients with HH were investigated with regard to chemotactic responsiveness (MCR). Two different methods were used at two different laboratories. Casein and zymosan-activated serum were used as attractants. No difference in MCR was found between the control group and the group of HH patients. The conclusion can therefore be drawn that the abnormal location of the macrophages of the gut wall in HH cannot be explained by an inborn abnormality of the function of receptors responsible for the chemotactic activity of the monocyte-macrophage system. It is, however, still possible that local factors responsible for the macrophage migration (gut hormones?) may have defective activity in HH patients.

Adult↗
PubMed1985

Transferrin receptors on circulating monocytes in hereditary haemochromatosis.

In patients with hereditary haemochromatosis (HH) abnormal functional properties of the macrophage system have been observed. The present study is a preliminary report of increased transferrin receptor expression on monocytes from 12 patients with HH. There was no correlation between the degree of iron overload and the transferrin receptor expression on the monocytes. The results obtained thus indicate that the observed increase in transferrin receptors is not a secondary phenomenon due to systemic iron overload but could be an expression of a primary inborn error of iron metabolism in HH. The functional aspects of the receptors were not evaluated as they were analyzed by means of monoclonal antibody technique.

Adult↗
PubMed1983

Iron absorption from some Asian meals containing contamination iron.

Iron absorption was measured from 12 Asian meals using the extrinsic tag method. Up to 50% of the nonheme iron in the meals did not exchange with the added inorganic radioiron tracer. The extent of isotopic exchange, the native iron and the "contamination" iron was measured using a recently developed in vitro method. The results imply that in measurements of iron absorption from meals, especially in developing countries, it is essential to consider the presence of contamination iron and its limited bioavailability.

Absorption↗
PubMed1981

Measurement of iron absorption from meals contaminated with iron.

A method is described to measure in vitro the extent of isotopic exchange between the native nonheme food iron and added inorganic reduction to radioiron tracer. The food is digested with pepsin and trypsin in the presence of radioiron. The exchangeability of food iron is calculated from the specific activity in the food and in an extract of bathophenantroline in isoamyl alcohol obtained after digesting this food. The precision and accuracy of the method is illustrated by two kinds of studies, those in which different amounts of contamination iron are added to a meal and those evaluating contamination iron in natural meals. The present method will make it possible to measure validly iron absorption from meals contaminated with unknown amounts of iron of unknown exchangeability with the extrinsic radioiron tracer.

Absorption↗
PubMed1980

Zinc absorption from composite meals. I. The significance of whest extraction rate, zinc, calcium, and protein content in meals based on bread.

The absorption of zinc in man from composite meals based on bread was measured with a radionuclide technique using 65Zn and whole-body counting. Bread was made up from wheat flour of 100 and 72% extraction rate. A lower absolute amount of zinc was absorbed from the white bread compared to the absorption from the same amount of wholemeal bread. When the two types of bread were enriched with zinc chloride the absorption was higher from the white bread than from the wholemeal bread. Addition of calcium in the form of milk products improved the absorption of zinc from a meal with wholemeal bread. A significant positive correlation was found between zinc absorption and the protein content in meals containing milk, cheese, beef, and egg in various combinations with the wholemeal bread.

Absorption↗
PubMed1980

Losses of ingested iron temporarily retained in the gastrointestinal tract. A possible auxiliary mechanism for regulation of iron absorption.

Excretion of radioiron 1 month after oral intake was studied in 6 healthy men by means of whole-body-counting. In one of the subjects as much as 17.6% of the 59Fe retained 2 weeks after oral intake was subsequently excreted. The radioiron losses were not due to bleeding. There was a fairly close positive correlation between iron status of the subjects and the amount of radioiron lost. It is thus probable that the observed losses of radioiron reflect a physiological mechanism which regulates iron absorption.

Digestive System↗