To evaluate the platelet function in sickle cell syndromes we measured the beta-thromboglobulin (beta-TG) and platelet factor 4 (PF-4) plasma values of 45 patients suffering from homozygous sickle cell anaemia (10) and sickle cell beta-thalassaemia (35) in steady state. The results were compared to those of 32 normal controls. Both the beta-TG and PF-4 levels were found to be significantly higher in patients than in controls but the beta-TG:PF-4 ratio was significantly lower in the patients group. This finding and the absence of any statistical correlation between platelet number and beta-TG or PF-4 indicate that platelets seem to be somehow activated in sickle cell syndromes, both in homozygotes and sickle cell/beta-thalassaemia heterozygotes. This platelet activation seems to exist even in steady state sickle cell disease patients, regardless of the functional status of the spleen.

The plasma clearance rate of heat denatured human serum albumin (DHAI-125, 5 mg/kg body weight) was studied in 20 children with homozygous-beta-thalassemia before and 7--10 days after blood transfusion. A significant increase of the DHAI-125 clearance rate (P less than 0.02) was found 7--10 days after blood transfusion while the spleen presented its minimum size. This finding may be relevant to the improved intrasplenic blood circulation after blood transfusion due to the release of the blood trapped within the spleen.

The kinetics of heat‐damaged homologous red blood cells (HDE) was studied prior to and 7–10 d following blood transfusion in 14 patients with homozygous ß‐thalassemia. On the basis of our results, ß‐thalassemic patients were classified into two distinct groups. In the first group the pretransfusion HDE extraction efficiency of the spleen was significantly lower than that of the second group and it increased dramatically following blood transfusion. On the contrary, the relatively higher pretransfusion HDE extraction efficiency of the patients of the second group showed a significant decrease after blood transfusion. These differences between the two groups of ß‐thalassemics might be attributed to the different qualitative as well as quantitative alterations of the splenic vascular bed occurring in these patients during the course of their disease. Furthermore, there was convincing evidence that part of the HDE mixture was extracted by RES sites outside the spleen, a function which is also affected by blood transfusion.

Patient doses for barium meal and barium enema examinations, performed at two Greek hospitals, were measured using a dose-area product meter. The results were analysed to obtain the contributions of fluoroscopy and radiography to the dose as well as a number of other dose related parameters for each examination. The doses observed are within the range of values reported by other authors and comply with the dose reference levels (DRLs), proposed from relevant surveys in the UK and The Netherlands. However, comparison between the two hospitals revealed significant differences in the contributions to dose from the various parts of the examinations. To determine the reasons for these differences, measurements of dose related parameters were made using a Plexiglas phantom and standard clinical X-ray machine settings. Factors contributing to increased dose delivery were determined and recommendations have been made concerning ways in which doses might be reduced in each hospital, without degradation of the diagnostic quality of these examinations.

The parameters of 51Cr labelled red cell survival curves were calculated in 33 patients with homozygous beta-thalassaemia, 8 with sickle-cell anaemia and 3 with s -- beta-thalassaemia, using a non-linear weighted least squares analysis computer program. In thalassaemic children the calculated parameters denote that the shortening of the mean cell life is due to early senescence alone, while there is some evidence that in thalassemic adults additional extracellular destruction mechanisms participate as well. Red cell survival curves from patients with sickle-cell anaemia and s -- beta-thalassaemia resemble each other, while their parameters indicate an initial rapid loss of radioactivity, early senescence and the presence of extracellular red cell destruction factors.