Growth characteristics of circulating hematopoietic progenitor cells from patients with essential thrombocythemia

Peripheral blood mononuclear cells from five patients with essential thrombocythemia (ET) were cultured in vitro to evaluate restricted megakaryocytic (CFU-Meg), myeloid (CFU-GM), and erythroid (BFU-E) progenitor cell development. Varying concentrations of aplastic canine serum served as the source of megakaryocyte colony-stimulating activity, and cultured megakaryocyte ploidy distributions were determined by Feulgen staining and microfluorometry. Megakaryocyte colony growth was strikingly abnormal in all five patients evaluated. Four of the 5 had a marked expansion in the concentration of circulating CFU-Meg and 3 of 4 manifested abnormalities in cultured megakaryocyte colony size (2 unusually large and 1 small). Unstimulated megakaryocyte colony growth was substantially increased in three patients. However, the fraction of megakaryocyte progenitors in cell cycle was near or below normal in all instances. Endomitotic megakaryocyte development was disordered in each of the four ET patients in whom it was evaluable. In normal subjects, mean megakaryocyte ploidy values vary biphasically with aplastic canine serum concentration and peak at 13.2 N following 12 to 15 days of culture. In contrast, day 12 mean ploidy values in cultures from the ET patients remained low at all aplastic canine serum concentrations and reached a maximum averaging only 8.4 N. Three patients were evaluated serially at extended culture durations of up to 21 days. The cultured megakaryocyte ploidy was unchanged during this interval for two of the patients. For the third patient, ploidy increased steadily, reaching abnormally high ploidy values by day 21. Progenitor cell expansion was limited to the megakaryocyte line in three patients. However, two patients had substantial increases in CFU-GM, one of whom also had a marked increase in BFU-E. There was no significant unstimulated colony growth by either CFU-GM or BFU-E. These data indicate that ET is usually characterized by an expansion in the concentration of circulating CFU-Meg in vivo which manifest both disordered replication and endoreduplication in vitro.     

Intraparental Inconsistency: The Influence of Parenting Behaviors on Aggression and Depression in Children

The authors examined several different predictive and mediation models of longitudinal parental inconsistency over a 3‐year time span. They hypothesized that parental behavior (communication/affection, kindness, and positive control) mediated the relationship between parental inconsistency (mother or father) and two emotional problems in children: (a) aggression and (b) depression. Data were obtained from a 3‐wave study (2007, 2008, and 2009) of 523 Spanish families with children ranging from 9–15 years of age at the beginning of Wave 1 (41.3% boys). Structural equation models revealed that multiple dimensions of parenting (mother or father) fully or partially mediated the relationship between longitudinal parental inconsistency and the child's adjustment. Communication/affection and kindness are the main processes through which parental inconsistency affects a child's aggression and depression. These results represent an important contribution to the improvement of parenting models of relationships between parental inconsistency and child adjustment.     

Life expectancy analysis in patients with Chagas' disease: prognosis after one decade (1973-1983)

We studied the evolution of chronic Chagas' disease in 107 patients with a positive Guerreiro-Machado reaction and 22 non-chagasic, non-heart disease control subjects for a follow-up period of 3 to 10 years (mean follow-up of 4.9 years). After completion of invasive and non-invasive studies, chagasic patients were classified into four groups: IA (normal ECG, without heart disease; 18 patients); IB (normal ECG, early left ventricular segmental abnormalities; 13 patients); II (abnormal ECG, advanced myocardial damage, no signs of heart failure; 42 patients); and III (abnormal ECG, end-stage, congestive heart failure; 34 patients). One out of five group IA patients re-studied with invasive methods evolved to group IB (20%); 4 group IB patients evolved to group II (33%) and 6 group II patients evolved to group III (15%). The life expectancy of patients in groups IA and IB (normal ECG) was similar to that of our control group, whereas in groups II and III it was significantly decreased (P less than 0.001). Nine group II patients (23%) and 28 group III patients (82%) died during the follow-up period. Main terminal events were refractory congestive heart failure, sudden death and systemic thromboembolism. Our findings suggest that chronic Chagas' disease follows an evolutionary course from asymptomatic, normal ECG group I stage to arrhythmic (II) and congestive (III) stages. Subjects with a positive Guerreiro-Machado reaction showed a significantly lower life expectancy than our control group, but only when clinical and/or ECG abnormalities were identified.     

Targeting NF-kappaB in Waldenstrom macroglobulinemia

The nuclear factor-B (NF-B) path-way has been implicated in tumor B-cell survival, growth, and resistance to therapy. Because tumor cells overcome single-agent antitumor activity, we hypothesized that combination of agents that target differentially NF-B pathway will induce significant cytotoxicity. Therapeutic agents that target proteasome and Akt pathways should induce significant activity in B-cell malignancies as both pathways impact NF-B activity. We demonstrated that perifosine and bortezomib both targeted NF-B through its recruitment to the promoter of its target gene IB using chromatin immunoprecipitation assay. This combination led to synergistic cytotoxicity in Waldenstrom macroglobulinemia (WM) cells that was mediated through a combined reduction of the PI3K/Akt and ERK signaling pathways, found to be critical for survival of WM cells. Moreover, a combination of these drugs with the CD20 monoclonal antibody rituximab further increased their cytotoxic activity. Thus, effective WM therapy may require combination regimens targeting the NF-B pathway.      

Combination of quinine as a potential reversing agent with mitoxantrone and cytarabine for the treatment of acute leukemias: a randomized multicenter study

A phase III prospective randomized multicenter study was performed to determine whether quinine could improve the response rate of poor-risk acute leukemias (ALs) to standard chemotherapy including a multidrug resistance (MDR)-related cytotoxic agent. The rationale of the study was based on the negative prognostic value of MDR phenotype in ALs and the ability of quinine to reverse this phenotype both in vitro and ex vivo. Three hundred fifteen patients (median age, 49 years; range, 16 to 65) with relapsed (n = 108) or refractory (n = 32) acute myeloblastic leukemia (AML), relapsed (n = 27) or refractory (n = 9) acute lymphoblastic leukemia (ALL), secondary AL (n = 22) or blastic transformation of myelodysplastic syndrome ([MDS] n = 74) or myeloproliferative syndrome ([MPS] n = 43) were randomly assigned to receive mitoxantrone ([MXN] 12 mg/m2/d, days 2 to 5) and cytarabine ([Ara-C] 1 g/m2/12 h, days 1 to 5) alone or in combination with quinine (30 mg/kg/d, days 1 to 5; continuous intravenous infusion beginning 24 hours before MXN infusion). Side effects of quinine were observed in 56 of 161 quinine-treated patients and disappeared in all but four cases after one or two 20% dose decreases. Sera from quinine-treated patients showed increased MXN uptake in an MDR-positive cell line compared with matched sera obtained before quinine infusion. Quinine induced a significant increase in the incidence of nausea, vomiting, mucositis, and cardiac toxicity. A complete response (CR) was observed in 85 of 161 patients (52.8%) from the quinine-treated group versus 70 of 154 patients (45.5%) in the control group (P = .19). The most important differences between quinine and control group CR rates were observed in patients with refractory AMLs and blastic transformation of MDS and MPS. The CR rate was higher in P-glycoprotein-positive cases, although the difference was not significant. Failure of the regimen due to blastic persistence or blast number increase was higher in the control group (61 of 154 patients) than in the quinine group (45 of 161, P = .04). Early death was observed in eight cases (four in each arm) and death in aplasia in 27 cases (20 in quinine group v seven in control group, P = .01). The significant increase of toxicity in the quinine arm could have masked the clinical benefit of MDR reversion in poor- risk ALs.     

Acute Chagas' disease: immunohistochemical characteristics of T cell infiltrate and its relationship with T. cruzi parasitic antigens

OBJECTIVE: The present work analysed endomyocardial biopsies of patients with acute Chagas' disease in order to evaluate the frequency and intensity of T. cruzi antigens, CD4+ and CD8+ T cells to determine the characteristics of this recurrent disease in Venezuela. MATERIAL AND METHODS: Twelve endomyocardial biopsies of patients with Chagas' disease, 12 to 51 years old, (7M and 5F) were analysed. T. cruzi antigens and CD4+ (helper) and CD8+ (cytotoxic-suppressor) T cells were detected by the immunoperoxidase technique.The presence and intensity of lymphocytic myocarditis was evaluated according to the degree of myocardial fibre injury caused by inflammatory infiltrate. RESULTS: Myocarditis was present in 100% of the cases. The mean numbers of CD4+ T cell and CD8+ T cell were 11.00 (+/- 10.29); 14.69 (+/- 13.08) and the CD4/CD8 T cell ratio was 0.75. T. cruzi antigens were detected in 58%. There was a good correlation between the numbers of CD4 and CD8 T cells of each case and a lack of correlation with the amount of T. cruzi antigens. CONCLUSION: All patients with acute Chagas' disease show some degree of myocarditis that seems to be directly related to the presence of parasitic antigens. Both CD4 and CD8 T cells participate in this process.We are following these patients to see if patients with severe myocarditis and more parasite antigens in the acute phase will develop chronic heart failure.     

Liver-derived fetal hematopoietic stem cells selectively and preferentially home to the fetal bone marrow

In the course of ontogeny, the homing site for the hematopoietic stem cells (HSC) moves with certain predictability from the yolk sac to the liver/spleen and then to the marrow. The pattern of this migration has thus far been established mostly on a morphologic basis. To delineate further the course of this migration and to gain insight into its possible mechanism, we used in utero transplantation of allogeneic or xenogeneic HSC in preimmune sheep fetuses. Sex chromosome, type of hemoglobin, and species-specific surface markers were used to follow the path of transplanted cells in the fetus. Before the development of the bone marrow, transplanted HSC (liver- or marrow-derived) homed exclusively to the liver/spleen. With the development of marrow, around day 60 of gestation (term, 145 days), homing occurred also in the nascent marrow and by day 80 transplanted cells homed exclusively to the marrow. This suggests that there may be a hierarchy in homing sites, with those of the marrow having higher affinity than those of liver/spleen. Interestingly, despite a change in homing that was followed by the expansion of the marrow compartment of HSC (ie, HSC proliferation), these cells did not participate actively in blood cell formation during most of the prenatal period. Liver remained the major hematopoietic organ throughout the gestation. It was only during the perinatal period that this organ assumed the function of hematopoiesis from the liver. This lack of expression of HSC in fetal marrow can possibly be attributable to the immaturity of marrow stroma required for differentiation and maturation of progenitors and the orderly egress of mature cells into the blood stream. The availability of this model allows us to begin studies in the molecular mechanism of stem cell homing in vivo during ontogeny.