Clinical and laboratory haematology最新文献

A new high oxygen affinity haemoglobin with the beta chain mutation beta146 HIS --> TYR is described. This variant was detected in a fit 34-year-old man with true erythrocytosis. The abnormal haemoglobin was identified as an extra band on cellulose acetate electrophoresis at pH 6.3 and was later confirmed by beta globin gene sequencing and oxygen dissociation studies. Whole blood containing Haemoglobin Hallamshire has a P50 of 18 mmHg. This newly described haemoglobin variant was also responsible for erythrocytosis in the mother and maternal half cousin of the index case. The identification of Haemoglobin Hallamshire provides confirmatory evidence of the important role of the C-terminal end of the chain in haemoglobin function.

The Bayer H1 automated blood counter was used to assess the MCHC values of 40 nonanaemic patients with HbC trait, 21 with HbD trait, 23 with HbE trait and 69 with HbS trait. These were compared with values from controls with a normal Hb phenotype. Values were significantly higher in those with HbC, D and S traits and approached significance in those with HbE trait. In 45%, of subjects with HbC trait the MCHC value was > or = 35 g/dl. Such values may prove a useful marker for this abnormality. In a further 12 patients with HbC, D, E or S traits and coexisting iron deficiency anaemia, MCHC values were usually higher and the percentage of hypochromic cells (red cells with CHC <28 g/dl, directly measured by the H1) usually lower than values derived from controls with a normal Hb phenotype and iron deficiency anaemia of similar degree. In individuals with HbC, D, E or S traits, the MCHC and proportion of hypochromic cells are less sensitive indicators of iron lack than in subjects with a normal Hb phenotype.

Renal disease is characterized by failure of erythropoietin (Epo) production and low bone marrow sensitivity to Epo. The reticulocyte count is the best laboratory marker of erythropoiesis available, but reticulocytes have not been extensively studied in renal disease. Cluster analysis suggests that in non-haemodialysed renal patients the anaemia is associated with uraemia while the reticulocyte number and immature subclasses are correlated with the ineffective erythropoietic component of the anaemia. This emphasizes the importance of treating the renal disease in patients with the anaemia of end-stage renal failure. Human recombinant Epo therapy has been demonstrated to be effective in correcting anaemia in most cases of chronic renal insufficiency. In renal patients the reticulocyte count should only be monitored by automated methods to assure reliability at low counts.

The aim of this project was to study haematological recovery in patients following different types of bone marrow transplantation (BMT). Forty-three patients were analysed. The duration of haematopoietic suppression following conditioning regimens was much shorter in 12 peripheral blood stem cell transplantation patients than in 19 allogeneic BMT patients and in 12 autologous BMT patients. Among 12 different variables, the parameters with the highest specificity or predictive value for monitoring recovery in these patients were the absolute neutrophil count (ANC) at the classical cut-off point of 0.5 x 10(9)/l, an absolute reticulocyte count (RET) above 20 x 10(9)/l and a high fluorescent reticulocyte fraction (HFR) above 5%,. It is suggested that these parameters be used as the reference measurements for monitoring haematological recovery in similar studies. Among these variables, the HFR fraction was the earliest and most sensitive index of engraftment in 79.1% of patients, HFR recovery requiring a median time of 13 days after infusion, in comparison with a median period of 19 and 18 days, respectively, for RET and ANC (P<0.0001).

Abnormal platelet function plays an important role in atherosclerosis and thrombotic disorders. Simple in vitro testing of platelet function is preferable to other techniques, and adhesion measurement is especially important because it reflects an immediate platelet response. The time lapse after venipuncture and the anticoagulant may affect platelet function in an as yet unknown way. A method for determining platelet adhesion under controlled whole blood flow conditions and an aggregation study were used. Platelet adhesion and aggregation changed significantly with time elapsed since venipuncture, peaking after 60 min (P < 0.05): a plateau was reached only after more than 120 min. Platelet adhesion was directly suppressed by the use of sodium citrate as an anticoagulant, and surface density decreased from 14.2 to 8.8 (P < 0.001). To prevent the effect of time after venipuncture on platelet function, testing should be performed at the plateau phase.

We have applied dual angle laser scattering cytometry (DALC), which provides objective assessment of spherocytosis, to study the changes of hereditary spherocytosis (HS) red cell populations after splenectomy. Eighty unsplenectomized HS patients (32 mild, 37 moderate and 11 severe cases), 26 splenectomized HS patients (SHS, formerly 21 moderate and five severe cases) and 140 controls were studied. SHS were similar to unsplenectomized mild HS cases, with homogeneous red cell volume distribution and spherocytosis. Spherocytosis in SHS was significantly higher when compared with controls (P < 0.001) but less when compared with unsplenectomized HS patients (P < 0.01).

Blast cells from a majority of acute myelogenous leukaemia (AML) patients express c-kit mRNA. However, c-kit expression has not been observed in patients with acute lymphoblastic leukaemia (ALL) and lymphoproliferative disease. We report here the detection of an abnormal sized c-kit mRNA in two Hong Kong Chinese patients with pre-B ALL and common ALL.

We report the second case of an acquired heparin-like anticoagulant in a patient with disseminated breast carcinoma. All but one of the small numbers of other cases have also been associated with an underlying malignancy. We comment on the distinction between an immunoglobulin and proteoglycan causing the antithrombin effect and suggest points of interest for consideration in any future cases together with a review of treatment options.

A collaborative study was undertaken to investigate the effect of storage conditions on the measured reticulocyte count in venous blood samples. It was designed to cover variation in the three main determinants, namely time, temperature and anticoagulant. The aim was to determine the time for which samples could be stored for subsequent analysis for clinical purposes.