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Biomedical subjects

B Wonke

Publications and source records attributed to B Wonke.

81 records · Page 5Linked to original sources
PubMed1985

A prospective trial of young red cells in 48 patients with transfusion-dependent thalassaemia.

Young red cells (YRBC) prepared on a cell washer were compared to whole blood in a randomized prospective trial in 48 transfusion dependent patients with thalassaemia major. A minor but statistically significant decrease in blood consumption was observed in the group receiving YRBC. However, no difference was seen in transfusion interval, mean haemoglobin and rate of haemoglobin fall between the two groups. Filtered blood was shown to be as effective as frozen blood in eliminating non-haemolytic febrile transfusion reactions in all the trial patients. We conclude that any reduction in the rate of iron loading brought about by the use of YRBC is clinically insignificant and does not justify the expense, time and work required to produce young red cells for use in a large transfusion dependent thalassaemic population.

Adolescent↗
PubMed1984

Ocular changes in patients undergoing long-term desferrioxamine treatment.

In a group of young patients with thalassaemia and iron overload treated by subcutaneous infusions of desferrioxamine we have found a number of minor alterations in retinal function. The incidence of such changes is not related to drug dosage or to ferritin level but to abnormality of the extended glucose tolerance test.

Adolescent↗
PubMed1984

The interpretation of platelet kinetic studies for the identification of sites of abnormal platelet destruction.

The kinetics of platelets labelled with 111In have been studied in a series of 175 subjects including 18 normal volunteers, and 12 patients with idiopathic thrombocytopenic purpura (ITP), but excluding patients in whom there was scintigraphic evidence of intravascular platelet consumption. From analysis of the kinetics, the following parameters were calculated: splenic blood flow (SBF), intrasplenic platelet transit time (t-), splenic platelet pool capacity (expressed as a percentage of the total circulating platelet population), the fraction of the dose of labelled platelets ultimately destroyed in the spleen and the mean platelet life span (MPLS). SBF increased with increasing spleen size up to values of 25% total blood volume (TBV) per min. Some patients with immune complex related diseases were identified with elevated SBF (up to 24% TBV min-1) but without significant splenomegaly. Patients with cardiac decompensation had reduced SBF relative to spleen size. t- showed no relationship with spleen size. It tended to fall in patients who had high SBF relative to spleen size and to rise in those with low SBF relative to spleen size; i.e. it was inversely related to splenic perfusion (flow per unit tissue volume). The splenic platelet pool capacity is dependent on platelet input (SBF) and splenic platelet clearance (reciprocal of t-), and showed a close relationship with spleen size. When all subjects except those with ITP were considered, splenic platelet destruction showed a good correlation (r = 0.70, n = 42, P less than 0.001) with the splenic platelet pooling capacity. The ratio of the fraction of platelets destroyed in the spleen to the fraction pooling there, the D/P ratio, was approximately unity and did not appear to vary with MPLS, spleen size or the patient's condition, except in ITP where it varied between about 0.5 and 2. This variation in ITP was thought to be the result of an immune mediated re-direction of reticulo-endothelial platelet destruction. It is suggested that the D/P ratio, rather than the absolute quantity of 111In labelled platelets destroyed in the spleen, may be a more useful predictor of response to splenectomy since it takes into account the observed, appropriate, tendency for the spleen to destroy platelets in proportion to its platelet pooling capacity.

Blood Flow Velocity↗
PubMed1983

Use of bone-marrow culture in prediction of acute leukaemic transformation in preleukaemia.

Bone-marrow granulocyte-macrophage progenitor cell proliferation and regulatory factor (colony-stimulating activity; CSA) production were assessed at presentation and, if possible, subsequently in twenty-one patients with dysmyelopoiesis and less than 5% bone-marrow blasts. Seven patients underwent acute leukaemic transformation 1-35 months after the first marrow culture. Assay of bone-marrow endogenous CSA proved the most useful prognostic test. The rate of transformation in the seven patients with raised CSA at presentation was significantly greater (five transformed and one died at or before 4 months) than that in the fourteen patients with normal, low, or undetectable CSA (two transformed at 27 and 35 months). In one of the latter an increase in bone-marrow CSA occurred 6 weeks before transformation (serial marrow samples were not available in the other case). No other marrow culture feature measured, including the presence or absence of granulocyte-macrophage colony-forming cells and total clone numbers (colonies and smaller clusters) was as useful.

Adult↗
PubMed1981

Terminal deoxynucleotidyl transferase expression in acute non-lymphoid leukaemia: an analysis by immunofluorescence.

Indirect immunofluorescence for terminal transferase enzyme (TdT) was used to study the blasts of 64 patients with acute non-lymphoid leukaemia (ANLL). In 32 patients no TdT positive cells were seen. In 19 cases a small subpopulation of cells expressing TdT was detected; these constituted up to 5% of total nucleated cells, and it was not clear whether these TdT positive cells were part of the leukaemic process or represented residual normal bone marrow lymphoid cells. The remaining 13 patients had TdT positive cells accounting for 7-90% of the total. In two of these cases TdT was expressed on blasts with myeloid features, representing an aberrant expression of TdT by myeloid cells; in contrast, in three cases mixed populations of TdT positive lymphoid blasts and TdT negative myeloid blasts were observed. In the remaining cases it was not possible to determine whether the TdT positive cells had definite lymphoid or myeloid features. Cytogenetic analysis showed no evidence of the Philadelphia chromosome. Response to treatment was assessed in 11 of the 13 patients. Only one patient remitted with the initial choice of therapy (DAT); four failed to respond to initial regimes of vincristine and prednisone (V & P) while the other five patients did not respond to myelotoxic combinations (DAT). Only one patient subsequently entered complete remission on second line therapy (V & P). This group of patients with TdT+ ANLL had a particularly bad prognosis, and appeared to differ from cases of TdT positive acute undifferentiated leukaemia, which often respond to V & P therapy.

Acute Disease↗
PubMed1980

Remission induction with adenosine-deaminase inhibitor 2'-deoxycoformycin in Thy-lymphoblastic leukaemia.

Two patients with relapsed acute lymphoblastic leukaemia of thymic phenotype (Thy-ALL) resistant to all conventional chemotherapy achieved complete remission when treated with 2'-deoxycoformycin, a selectively lymphocytotoxic compound that acts by inhibition of the enzyme adenosine deaminase. These observations show that malignant thymocytes are dependent on adenosine-deaminase activity and suggest that it may be possible to use deoxycoformycin in other patients with Thy-ALL to induce remission or to kill Thy-ALL blasts in bone marrow harvested before autologous bone-marrow transplantation, leaving normal haemopoietic stem cells intact.

Adenosine Deaminase↗