Serum erythropoietin changes in autologous and allogeneic bone marrow transplant patients

Sequential changes in serum erythropoietin (sEPO) levels were measured by radioimmunoassay in six patients receiving autologous rescue (AR) and 11 patients receiving an allogeneic bone marrow transplant (BMT) for malignant disease. Longitudinal studies showed an inverse relationship between sEPO and haemoglobin levels in the autologous rescue and allogeneic transplant patients throughout the 130 d post-transplant study period. Early post-conditioning EPO responses were normal for the haemoglobin level in both groups, but after day 14 post-transplant, erythropoietin production in response to anaemia became impaired in one autologous rescue patient and eight of the 11 allogeneic transplant patients. There was no clear association between late impairment of sEPO production and conditioning therapy, infection, graft-versus-host disease, immunosuppressive therapy or serum creatinine. Blood transfusion requirements were similar for both groups in the first month after transplantation, but from days 31 to 90 post-transplant, BMT patients required an average of 5.5 units per patient compared with 1 unit per patient for the autologous group. Marrow transplant procedures do not affect early EPO responses but may diminish late responses. The potential value of exogenous rHuEPO in hastening engraftment and decreasing transfusion requirements, particularly for those patients who appear to have impaired EPO responses, remains to be shown by clinical trials.     

Immunogenic nature of a Pol gene product of HTLV-III/LAV

The present studies were initiated to define the coding region of a 34 kilodalton (kd) protein (p34) frequently observed with antibodies from HTLV-III/LAV-infected people by immunoblotting and radioimmunoprecipitation (RIP) techniques. We have directly mapped this viral protein to the pol gene of HTLV-III/LAV by radiolabeled amino acid sequence analysis. This region at the 3' end of the pol gene is predicted to encode the endonuclease/integrase of the virus. The seroprevalence rate of antibodies to the pol gene products p64 and p53 and to the endonuclease p34 were evaluated. Of 161 HTLV-III/LAV seropositive people tested by immunoblotting procedures, greater than 98% had antibodies which reacted to p64/p53 and 92.6% reacted to p34 indicating that these viral proteins are highly immunogenic in nature. We have also analyzed the serum of nine healthy people living in West Africa who were infected with HTLV-IV, a closely related retrovirus. Nine of nine seropositive people had antibodies that cross-reacted to p34 of HTLV-III/LAV, whereas only seven of nine reacted to p64/p53. These studies and our earlier observations indicate that current diagnostic procedures for screening for HTLV-III/LAV infection may also detect HTLV-IV seropositive individuals, pointing to a need for more specific assay systems.     

Plasmapheresis in the treatment of thrombotic thrombocytopenic purpura

Two patients with thrombotic thrombocytopenic purpura (TTP) have recovered completely after intensive plasmapheresis. The mechanisms responsible for the improvement in these instances are most likely related to the removal of an inciting or damaging agent. The possibility that this agent may be an immune complex is discussed. Plasmapheresis appears to be useful therapy for some patients with this syndrome.     

Tranexamic acid and upper gastrointestinal haemorrhage--a double-blind trial.

The efficacy of antifibrinolytic therapy in the management of acute upper gastrointestinal haemorrhage has been investigated in a double-blind clinical trial. Two-hundred patients were studied using tranexamic acid, a potent antifibrinolytic agent. Of these, 103 were in the treatment group and 97 in the control group. Patients were analysed to determine severity of initial blood loss, transfusion requirements, together with the incidence of recurrent bleeding, surgical intervention, and death. Final diagnosis as to the site of bleeding was arrived at using endoscopy, barium studies, and the findings at operation and necropsy. The groups were well matched as regards severity of initial haemorrhage, age, sex, aetiological diagnosis, and precipitating factors. A significant difference was observed in the requirement for surgical intervention to control continuing or recurrent haemorrhage. Twenty-three of 97 in the control group and seven of 103 in the treatment group required surgery.There appeared to be a reduction in the transfusion rate after the first three days of hospitalization in the treatment group. There were no significant differences in mortality or in side-effects between the two groups.     

The contribution of blast cell properties to outcome variation in acute myeloblastic leukemia (AML)

The blast cell population in AML includes progenitors capable of colony formation in culture. Certain properties of these progenitors have been determined, including their capacity for self-renewal and their sensitivities to the chemotherapeutic drugs cytosine arabinoside (Ara- C) and adriamycin (Adria). Wide patient to patient variation was found in these properties, although they were stable during the course of the disease in each patient. We tested the properties, together with clinical risk factors, as attributes contributing to the variation in remission induction and survival. As univariate parameters, self- renewal and Ara-C sensitivity contributed to remission induction, but only self-renewal was related to survival. In multivariate analysis, self-renewal, age and percentage blasts in the marrow contributed to outcome variation; drug sensitivities were not significant. We conclude that self-renewal, a biological property of malignant AML clones, although measured in culture, plays a significant role in determining response to treatment and survival in AML.     

The Role of Platelets in Intrinsic Factor-Xa Formation

Although the essential role of phospholipid in the interaction of factors VII and IX has been demonstrated (Lundblad & Davie, 1964), detailed studies of platelet activity in intrinsic coagulation have not previously been reported. A basic test system has been developed for studying the interaction of factors XIa, VIII, IX, and X in the formation of factor Xa. Using platelets from normal and coagulation-factor-deficient donors, washed by albumin density gradient separation (ADGS), a comparative study of platelets and phospholipid in intrinsic factor-Xa formation has been done under various test conditions.
Both platelets and phospholipid (Folch) are shown here to play a part in intrinsic factor-Xa formation, whereas neither enhances extrinsic factor-Xa formation. Collagen promotes a platelet coagulant activity which increases the rate of factor-Xa formation in the test system employed. The effect of collagen depends entirely on the presence on the platelet surface of factor XI, but not of factor XII. In contrast to collagen, adenosine diphosphate has no effect on this intrinsic platelet coagulant activity. In experiments carried out in the presence of naturally-occurring inhibitors to active clotting factors (anti-factors Ila, Xa, and XIa) it is shown here that contact product is adsorbed to the platelet surface where it is protected from destruction by antifactor XIa. Factor Xa is formed subsequently by the interaction of intrinsic clotting factors, which is presumed to occur on the platelet surface since factor Xa is found in association with the platelets, not the surrounding plasma.     

Fate of the DNA in plasmid-containing Escherichia coli minicells ingested by human neutrophils

Escherichia coli minicells containing the plasmid pSC101 (approximately 10 kb) or pBR322 (approximately 4 kb) were opsonized and incubated with human neutrophils. The neutrophils responded to the minicells as they would to native E coli: they ingested the minicells, discharged their granule contents into the minicell-containing phagosomes, and expressed a respiratory burst. After one hour of incubation, the fate of the ingested plasmid DNA was examined. No DNA degradation was detected by trichloroacetic acid precipitation or agarose gel electrophoresis. Moreover, when pBR322 recovered from ingested minicells was transformed into E coli, no mutations in either of the antibiotic resistance genes carried by the plasmid were detected out of many thousand transformants screened. These findings confirm the surprisingly limited effect of neutrophils on ingested DNA.     

Bladder irrigation does not prevent haemorrhagic cystitis in bone marrow transplant recipients

Thirty-four patients receiving allogeneic bone marrow transplants as treatment for haematological malignancy were prospectively randomized to receive or not to receive bladder irrigation by indwelling urinary catheter during preparation for transplant. Twenty-two patients received busulphan and cyclophosphamide, four received busulphan, cyclophosphamide and irradiation, and eight received cyclophosphamide and total body irradiation. The actuarial incidence of haemorrhagic cystitis in those randomized to receive bladder irrigation was 48% for the whole group and 52% in those receiving busulphan and cyclophosphamide only. In those randomized not to receive bladder irrigation the incidence of haemorrhagic cystitis was 29% for the overall group and 38% in those receiving busulphan and cyclophosphamide. There was no statistically significant difference between the two groups. We conclude that bladder irrigation does not minimize the risk of haemorrhagic cystitis in this patient population.