Search

The use of normal immersion oil, developed for 23°C, at 37°C greatly compromises both axial resolution and signal intensity. We developed and characterized an immersion oil for optimal performance in live-cell imaging at 37°C. We quantify the improvements in resolution and intensity obtained when using the new oil instead of its standard 23°C counterparts. [ABSTRACT FROM AUTHOR]

Frequent blood donors become iron deficient. HFE mutations are present in over 30% of donors. A 24-month study of 888 first time/reactivated donors and 1537 frequent donors measured haemoglobin and iron status to assess how HFE mutations impact the development of iron deficiency erythropoiesis. Donors with two HFE mutations had increased baseline haemoglobin and iron stores as did those with one mutation, albeit to a lesser extent. Over multiple donations haemoglobin and iron status of donors with HFE mutations paralleled those lacking mutations. The prevalence of HFE mutations was not increased in higher intensity donors. Thus, in general, HFE mutations do not temper donation-induced changes in haemoglobin and iron status. However, in Black donors there was an increase of H63D carriers at baseline, from 3·7% in first time/reactivated donors to 15·8% in frequent donors, suggesting that the relative effects of HFE mutations on iron absorption may vary between racial/ethnic groups. In secondary analyses, venous haemoglobin decreased more slowly in donors with ferritin ≥12μg/l; and haemoglobin recovery time was shorter in donors with reticulocyte haemoglobin (CHr) ≥32·6pg, indicating that these biochemical measures are better indicators of a donor's response to phlebotomy than their HFE mutation status., (© 2011 Blackwell Publishing Ltd.)

Large lymphocytes with basophilic cytoplasm and cleaved/cerebriform nuclei called flower cells have been described in human T-lymphotrophic virus type I (HTLV-I) seropositive individuals and may be precursors of adult T-cell leukaemia (ATL). A cohort of 546 HTLV-seropositive former blood donors, 32 HTLV-positive sexual partners of these donors and 799 HTLV-seronegative controls has been followed as part of the Retrovirus Epidemiology Donor Study. A novel methodology was developed to systematically review peripheral blood slides from these subjects for HTLV-related lymphocyte abnormalities, using an algorithm based on morphologic features to objectively identify flower cells. The algorithm included: absence of azurophil granules; nuclear chromatin condensation; cell size >1.5 small lymphocytes; nuclear to cytoplasmic ratio >80%; and presence of nuclear folding/lobulation. Peripheral slides from subjects were screened by a medical technologist blinded to HTLV status. 6.8% of HTLV-I subjects (P = 0.0001 versus seronegatives), 0.9% of HTLV-II subjects and 1.1% of seronegatives were confirmed to have cells classified as flower cells by two haematologists using objective criteria, and blinded to serostatus. Despite the higher prevalence of flower cells in HTLV-I positives, no clinical correlations were found. Longitudinal follow-up may yield higher rates of cellular abnormalities as the sequelae of HTLV infection develop.

Recombinant human erythropoietin (EPO) therapy has been shown to increase red blood cell (RBC) production and facilitate autologous blood donation before elective surgery. However, recent reports have suggested that surgery and/or EPO therapy may suppress endogenous erythropoietin secretion in response to anaemia. We therefore analysed the haemoglobin/erythropoietin relationship preoperatively and postoperatively in 71 autologous blood donors subjected to aggressive phlebotomy and six treatments with either EPO (150 U/kg, n = 16, 300 U/kg, n = 18, or 600 U/kg, n = 19) or placebo (n = 18). Using data from the three preoperative study visits, the linear relationship between log erythropoietin and haemoglobin was determined for each of the 18 placebo patients. We found no significant differences in the slopes of the relationships in this group during aggressive phlebotomy. Furthermore, there was no evidence of a significant difference in the erythropoietin level recorded postoperatively for each patient to that predicted from the patient's postoperative haemoglobin level, based on the haemoglobin/log erythropoietin relationship preoperatively. Similarly, for each of the EPO-treated groups, there was no evidence of a significant difference when comparing the recorded erythropoietin level to that predicted from each patient's postoperative haemoglobin level, based on the haemoglobin/log erythropoietin relationship preoperatively. We conclude that preoperative recombinant human erythropoietin therapy and/or surgery do not adversely affect the postoperative erythropoietin response to anaemia.

A woman with metastatic breast carcinoma developed acute haemolytic anaemia on two occasions following treatment with methotrexate (MTX) and 5-fluorouracil (5-FU). The direct antiglobulin test was positive. Compatible control cells were pretreated with either MTX or 5-FU and subsequently incubated with patient and control sera. Agglutination in the indirect antiglobulin test was observed only in the presence of patient serum and MTX, and did not occur following pretreatment with 5-FU, folic acid, folinic acid or triamterene. There was no evidence of complement binding to the red cell surface. A macrophage assay showed increased phagocytic uptake of MTX-treated cells in the presence of patient serum. This phagocytosis was not enhanced by the addition of complement. The antibody subclass was predominantly IgG-3. The 51Cr red cell survival of autologous MTX cells was markedly shortened, indicating rapid in vivo destruction. These studies demonstrate the occurrence of acute haemolytic anaemia due to an IgG-3 antibody that reacts with erythrocytes in the presence of methotrexate. This antibody does not fix complement, but sensitizes red blood cells to phagocytosis by macrophages.

Mechanisms of thrombus formation in myeloproliferative disease were studied using a technique which visualized platelet-vessel wall interactions under physiological conditions of blood flow. Whole blood from four patients with chronic myelogenous leukaemia and three with thrombocythaemia were pumped through perfusion chambers containing de-endothelialized artery segments. Platelet reactivity with vessel walls (thrombus formation) was measured in sections of vessels by light microscopy and quantitative morphometric analysis. Five patients produced platelet reactivity values of 130--258% of controls while two gave decreased values. The two highest platelet reactivity values occurred in samples with elevated platelet counts and normal haematocrits. In contrast, when anti-platelet drugs were administered to three patients with high platelet counts, reactivity values decreased to 11--34% of controls. Clinical correlations revealed that patients with highest platelet reactivity values (165--258%) were those subjects who also exhibited thrombotic or haemorrhagic complications. Thus absolute platelet count and haematocrit may be major determinants in predicting these complications. Qualitative evaluations of thrombus formations by light and electron microscopy provide further evidence that platelets in myeloproliferative disease also possess qualitative abnormalities.