Hematopoietic stem cell transplantation for multiply transfused patients with sickle cell disease and thalassemia after low-dose total body irradiation, fludarabine, and rabbit anti-thymocyte globulin

Patients with sickle cell disease (N = 3) and thalassemia (N = 1) with high-risk features received hematopoietic stem cell transplantations (HCT) to induce stable (full or partial) donor engraftment. Patients were 9-30 years of age. Fludarabine, rabbit anti-thymocyte globulin (ATG), and 200 cGy total body irradiation were administered pre-transplant. Patients received bone marrow (N = 3) or peripheral blood stem cells (N = 1) from HLA-identical siblings, followed by mycophenolate mofetil and cyclosporine for post-grafting immunosuppression. Significant lymphopenia, but only moderate neutropenia and thrombocytopenia developed post transplant. No grade IV nonhematological toxicities or acute graft-versus-host disease (GVHD) were observed. At 3 months after transplantation, three of four patients had evidence of donor myeloid chimerism (range, 15-100%). However, after post transplant immunosuppression was discontinued, graft rejection occurred in all but one patient. This patient is now doing well 27 months post transplant with full donor engraftment. One patient died after a second transplant, and another patient experienced a stroke as her graft was being rejected. These results suggest that stable donor engraftment after nonmyeloablative HCT is difficult to achieve among immunocompetent patients with hemoglobinopathies and that new approaches will need to be developed before wider application of this transplantation method for hemoglobinopathies.

Survival after HLA-identical allogeneic peripheral blood stem cell and bone marrow transplantation for hematologic malignancies: meta-analysis of randomized controlled trials

The impact of peripheral blood stem cell transplantation (PBSCT) on survival relative to bone marrow transplantation (BMT) remains poorly defined. Several randomized controlled trials (RCTs) comparing HLA-matched related PBSC- and BMT for patients with hematologic malignancies have been published, yielding differing results. We conducted a meta-analysis of published RCTs to more precisely estimate the effect of PBSCT on survival. Seven trials that assessed survival were identified and included in our analysis. Using a fixed effects model, and combining the results of all seven trials, the summary odds ratio for mortality after PBSCT was 0.81 (95% CI, 0.62-1.05) when compared to BMT. Subgroup analysis revealed no association between the median PBSCT 34+ cell dose and relative risk for morality after PBSCT. However, there was an association between the proportion of patients enrolled with advanced-stage disease and the summary odds ratio for mortality. The pooled estimate was 0.64 for studies where patients with intermediate/advanced disease comprised at least 25% of enrollment, and was 1.07 for the studies enrolling a smaller proportion. This finding substantiates results from previously published studies that have demonstrated a survival advantage with PBSCT limited to patients with advanced disease.

Fibrin degradation products, fibrin monomer and soluble fibrin in disseminated intravascular coagulation

Disseminated intravascular coagulation (DIC) is characterized by activation of hemostasis and fibrinolysis resulting in the formation of thrombin and plasmin, and the characteristic effects of these enzymes on plasma fibrinogen can be useful in diagnosis. Thrombin cleaves fibrinopeptides from fibrinogen, forming fibrin monomer that rapidly polymerizes to form a clot. Small amounts can circulate in plasma as "soluble fibrin," which may have a complex composition and include fibrinogen and a variable amount of cross-linking. Plasmic degradation of cross-linked fibrin forms a heterogeneous group of degradation products reactive in assays for D-dimer, and their levels provide a measure of the amount of fibrin formation and lysis. Caution should be exercised in comparing quantitative results using different assays because of problems with standardization and variable reactivity with different molecular forms. Marked elevations of fibrin(ogen) degradation products are a constant finding in experimental animal models of DIC. In human models of DIC resulting from endotoxin infusion, D-dimer is elevated early and high levels persist, reflecting lysis of microvascular fibrin deposits. Elevated levels of D-dimer and soluble fibrin are very sensitive for the diagnosis of DIC, and a normal level has a high negative predictive value. Serial monitoring of soluble fibrin or D-dimer assays may be of value in evaluating the response to therapy and possibly in identifying at-risk patients.

Prothrombotic changes in hemostatic parameters and C-reactive protein in the elderly with winter acute respiratory tract infections

Mortality rates attributable to cerebrovascular and ischemic heart disease increase among older adults during the winter. Prothrombotic changes in the hemostatic system related to seasonal factors, such as ambient temperature changes, and winter acute respiratory tract infections, may contribute to this excess seasonal mortality. A prospective nested case-control study was conducted to assess the impact of winter acute respiratory tract infections on fibrinogen, factor VII, factor VIIa, D-dimer, prothrombin fragment 1.2, PAI-1, soluble P-selectin and C-reactive protein (CRP) in older adults. The change in laboratory parameters from baseline (fall) to the time of infection in both middle-aged and elderly individuals was compared with matched non-infected controls. In older adult participants with winter acute respiratory tract infections, significant increases occurred in fibrinogen and C-reactive protein, but not in any other markers. The mean fibrinogen increased 1.52 g/L (38%) and the mean CRP increased 37 mg/L (370%) over baseline (both p <0.001). In a multivariate analysis, both infection and season were associated with the increase in fibrinogen, but only infection was associated with the CRP increase. Old age magnified the increase in CRP but not in fibrinogen. Winter acute respiratory tract infections induce an exaggerated inflammatory response in older adults. The associated increase in fibrinogen, an independent risk factor for ischemic heart disease, may be partly responsible for the excess winter vascular mortality.

Allogeneic bone marrow transplantation for children with acute leukemia: cytoreduction with fractionated total body irradiation, high-dose etoposide and cyclophosphamide

Marrow-ablative chemo-radiotherapy followed by hematopoietic stem cell rescue from an allogeneic source improves outcomes for children with high-risk acute leukemia. The first effective pre-transplant preparative regimens consisted of high-dose cyclophosphamide (CY) and total body irradiation (TBI). Subsequent attempts have been made to improve leukemia-free survival, by adding other chemotherapy agents to these agents. In previous clinical studies of total body irradiation, etoposide, cyclophosphamide (TBI-VP-16-Cy) in adult allogeneic bone marrow transplantation, there has been a high incidence of severe regimen-related toxicity. In this study, we investigated the safety and efficacy of this combination in 41 children who received TBI (12-14 Gy), VP-16 (30 mg/kg), and CY (60 mg/kg x 2) and then either matched sibling or alternative donor transplants for acute leukemia. There was only one case of fatal regimen-related toxicity. The estimated 3-year event-free survival for patients with early or intermediate stage disease was 68% (53-88%). The estimated event-free survival of patients with advanced disease was 17% (5-59%). TBI-VP16-CY is safe in pediatric transplantation, and it has good efficacy for transplant recipients with less advanced disease. Bone Marrow Transplantation (2000) 25, 489-494.

Automated latex agglutination and ELISA testing yield equivalent D-dimer results in patients with recent myocardial infarction. THROMBO Research Investigators

Our previous prospective study of post-infarction patients described a strong and significant association of increased plasma D-dimer concentrations in those who experienced a subsequent coronary death or non-fatal myocardial infarction. In the present study, we compare results on stored plasma obtained two months after the index myocardial infarction from 1,038 patients of this trial, using a simple automated latex agglutination (LA) assay in parallel with the standard ELISA test. Results show a somewhat higher mean value for the LA assay (702+/-1092 vs. 638+/-986 ng/ml, p = 0.0002), a strong linear correlation of the two assays (r = 0.86) and 88% agreement for values below 500 ng/ml by the ELISA test. D-dimer concentrations determined by each assay were highly correlated in patients with subsequent coronary artery events (p = 0.93) and quartile values for both the LA and ELISA were equally predictive of such events (p = 0.003 and p = 0.001, respectively). This is the first demonstration that a latex agglutination assay for D-dimer can be used to assess the prognostic risk of recurrent coronary thrombotic disease after myocardial infarction

Exposure to nicotine enhances acquisition of ethanol drinking by laboratory rats in a limited access paradigm

Observations in humans suggest that the initial use of tobacco occurs in close temporal proximity to experimentation with alcohol. There have been relatively few research reports, however, examining possible interactions between these two agents. The present experiments examined the effect of nicotine exposure on the acquisition of ethanol drinking behavior in a limited access procedure. In experiment 1, rats were presented with 1-h access to ethanol solutions of increasing concentration for a period of 20 days. Subcutaneous injections of nicotine (0.6 or 1.2 mg/kg salt) or vehicle were administered 30 min prior to each ethanol presentation. Experiment 2 used a similar method, but rats were presented with water along with ethanol during the 1-h test session. Mecamylamine, a nicotinic receptor antagonist, was administered 30 min prior to the nicotine treatment. Nicotine was seen to produce a dose-dependent increase in ethanol drinking behavior which commenced at the 5% ethanol concentration and continued at 8% and again at 10%. In the second experiment, mecamylamine was observed to block completely the nicotine-induced increase in ethanol drinking behavior. The findings suggest that exposure to nicotine can facilitate the acquisition of ethanol drinking behavior in naive rats and that this effect is mediated by nicotine's interaction at the nicotinic-cholinergic receptor.