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Biomedical subjects

L S Valberg

Publications and source records attributed to L S Valberg.

At least 73 records · Page 4Linked to original sources
PubMed1975

Serum ferritin, cobalt excretion and body iron status.

Serum ferritin concentration was measured by immunoradiometric assay in 64 subjects. It was closely related to the size of body iron stores measured by hemosiderin content of bone marrow in all subjects and by the deferoxamine test in 10 patients with iron overload. Urinary cobalt excretion, an indirect measure of iron absorption, was inversely related to hemosiderin content of bone marrow in 34 patients aged 18 to 72 with or without liver disease, but this relation did not hold in a group of 20 student volunteers aged 17 to 30, indicating that the test is unreliable in young people. A strong inverse correlation was demonstrated between values for cobalt excretion and serum ferritin in the 34 patients and between those for iron absorption and serum ferritin in the 20 students. Serum ferritin concentration appears to reflect accurately the iron status of the healthy individual but high values in liver disease must be interpreted with caution.

Adolescent↗
PubMed1975

A new type of facility in medical education: the Clinical Learning Center.

The two independent forces leading to the development of a new type of facility for medical education were the desire to utilize modern educational concepts (some of which are difficult to employ in traditional hospital settings) and the need to expand students' contact with clinical patients. This special facility, known as the Clinical Learning Center, resembles the ultimate setting of medical practice, that is, the physician's office, and it depends upon volunteer patients who come there primarily to contribute to the educational program while deriving no medical care. Students and instructors have appreciated the opportunity for feedback; the quiet educational environment; the graduated learning experiences; and the use of various resources, especially videotape recording and playback of the clinical encounter. The recruitment of volunteer patients has been highly successful, and the center is proving to be a valuable adjunct to the learning of clinical skills.

Attitude↗
PubMed1975

Integrity of the iron transport process in mice with X-linked anaemia.

The defect in iron (Fe) absorption in X linked anaemia (sla) remains an enigma; absorption of a tracer dose of Fe is impaired in mice raised on an iron-containing cube diet but not in those raised on an iron-deficient diet. Because cobalt (Co) shares a similar intestinal transport pathway with Fe, a study was made of the effect of iron deficient diet on Co absorption. The duodenum of sla and genetically normal mice was perfused for 30 min with labelled solutions containing Co or Fe. Co uptake and transfer were similar in sla and normals fed cubes whereas Fe uptake and transfer were less in sla than in normals. The iron deficient diet caused an increase in the uptake and transfer of Co and Fe in sla and normals. When Co and Fe were perfused together in sla fed deficient diet, the uptake and transfer of each metal was less than when performed alone. The distribution of Fe and Co in subcellular mucosal fractions was determined by a differential centrifugation technique. Deficient diet resulted in a directionally similar change in the subcellular distribution of Co and Fe in sla and normals. The increase in Co as well as Fe absorption in the sla on an iron deficient diet to the same high level found in genetically normal animals, and the inhibitory effect of each metal on the absorption of the other suggests that the absorption defect in sla is unlikely to be due to a primary defect in the function of the transport carrier.

Anemia, Hypochromic↗
PubMed1975

Distribution of storage iron as body stores expand in patients with hemochromatosis.

The relative distribution of storage iron between bone marrow and liver has not been adequately studied in patients with iron-loading disorders. To help clarify this we assessed iron metabolism in patients with iron overload and in control subjects with cirrhosis but no excess body iron. In 4 patients with advanced iron overload studied late in the course of their illness, excess hemosiderin was present in both bone marrow and liver, as expected. In contrast, 2 patients with idiopathic hemochromatosis whose excess iron had been depleted by phlebotomy subsequently developed progressive hepatic parenchymal and reticuloendothelial (RE) deposition of iron, yet marrow hemosiderin remained sparse. Moreover, surface radioactivity over the liver after an oral dose of 59Fe. These results suggest that during the initial stages of hemochromatosis there is a dissociation in the rate of iron accumulation between the bone marrow and liver. Excess hemosiderin appears to be deposited predominantly and preferentially in hepatic storage sites until the later stages of the disease.

Aged↗
PubMed1971

Cobalt excretion test for the assessment of body iron stores.

Iron absorption is under delicate control and the level of absorption is adjusted to comply with the body's need for iron. To measure the intestinal setting for iron absorption, and thereby indirectly assess body iron requirements, cobaltous chloride labelled with (57)Co or (60)Co was given by mouth and the percentage of the test dose excreted in the urine in 24 hours was measured in a gamma counter. Seventeen control subjects with normal iron stores excreted 18% (9-23%) of the dose. Increased excretion, 31% (23-42%), was found in 10 patients with iron deficiency anemia and in 15 patients with depleted iron stores in the absence of anemia. In contrast, 12 patients with anemia due to causes other than iron deficiency excreted amounts of radiocobalt within the normal control range. In patients with iron deficiency, replenishment of iron stores by either oral or parenteral iron caused the previously high results to return to normal.Excretion of the test dose was normal in portal cirrhosis with normal iron stores but it was markedly increased in patients with cirrhosis complicated by either iron deficiency or endogenous iron overload. It was also raised in primary hemochromatosis. Excretion of the dose was reduced in gluten-sensitive enteropathy. Gastrointestinal surgery and inflammatory disease of the lower small intestine had no effect on the results except that some patients with steatorrhea had diminished excretion.The cobalt excretion test provides the clinician with a tool for the assessment of iron absorption, the detection of a reduction in body iron stores below the level that is normal for the subject in question, the differentiation of iron deficiency anemia from anemia due to other causes, and the investigation of patients with iron-loading disorders.

Acute Kidney Injury↗