Intrasplenic blood cell kinetics in man before and after brief maximal exercise.

1. After a 4 min period of maximal exercise in 10 normal subjects (14 studies), there was a consistent decrease in total blood volume and a consistent increase in erythrocyte indices, which were maximal immediately after exercise. Peripheral platelet and leucocyte counts increased, but did not reach maximal values until 5-10 min after the end of exercise.

Detection and functional assessment of accessory splenic tissue (splenunculi) with radiolabelled heat damaged autologous erythrocytes.

Eight patients (six with idiopathic thrombocytopenic purpura, one with immune pancytopenia, and one with autoimmune haemolytic anaemia), who had previously been splenectomized, were found to have splenunculi using radioactively labelled heat damaged autologous erythrocytes. In all patients the splenunculi were found to have significant 'splenic function'. However, there was a poor correlation between the size and the function of the splenunculi.

Development of polycythaemia vera in a patient with myelofibrosis.

In March 1981, a 53-year-old man presented with itching and was diagnosed as having myelofibrosis. There was gradual enlargement of the spleen over the following 5 yr. His spleen had to be removed in February 1986 because of physical discomfort.

Radioisotope studies in monitoring of Gaucher's disease and its treatment.

Radioisotope studies (blood volume, spleen function, and ferrokinetics) were performed in seven patients with chronic (type 1) Gaucher's disease. Interestingly, the 52Fe scans and spleen histology demonstrated extramedullary haemopoiesis in the liver and spleen. Radioisotope measurements (red cell volume, plasma volume, red cell pool, damaged cell clearance, spleen blood flow, 59Fe clearance, red cell utilization and 52Fe scans) provide methods for accurate measurement of the bone marrow and spleen function, thereby enabling prediction of the most suitable time for splenectomy, in the treatment of patients with Gaucher's disease.

Erythrocyte radiolabelling: in vitro comparison of chromium, technetium, and indium in undamaged and heat damaged cells.

The stability of the commonly used red cell radio labels chromium-51, indium-(111 or 113m), and technetium-99m, within intact red cells and stroma and their distribution within the cell were compared in undamaged and heat damaged red cells in relation to the clinical use of heat damaged cells in the assessment of splenic function. Chromium-51 labelled haemoglobin both in undamaged and heat damaged cells; indium predominantly labelled haemoglobin in undamaged cells but labelled stroma in heat damaged cells, even when the cells were labelled before heating; technetium-99m predominantly labelled haemoglobin in undamaged cells but only labelled stroma in heat damaged cells if these were heated before labelling. Indium was more firmly bound by stroma prepared from heat damaged cells, and technetium-99m showed a high rate of elution both from cells and stroma, although this rate was lower for heat damaged cells.

Measurement of red cell volume and splenic red cell pool using 113m indium.

Using the lipophilic chelating agent, acetylacetone, red cells have been radiolabelled with the short-lived, generator-produced isotope, 113mIn. Following re-injection of these labelled cells, red cell volume has been measured and compared with corresponding values using 99mTc labelled red cells in 18 patients, and with 51Cr labelled red cells in five patients. 99mTc slightly overestimated red cell volume in relation to 113mIn, but 51Cr values were identical to 113mIn values.