Galectina-3 Associada a Formas Graves e Mortalidade em Longo Prazo em Pacientes com Doença de Chagas

Background The histopathological characteristics of Chagas disease (ChD) are: presence of myocarditis, destruction of heart fibers, and myocardial fibrosis. Galectin-3 (Gal-3) is a biomarker involved in the mechanism of fibrosis and inflammation that may be useful for risk stratification of individuals with ChD.Objectives We sought to evaluate whether high Gal-3 levels are associated with severe forms of Chagas cardiomyopathy (CC) and whether they are predictive of mortality.Methods We studied anti-T. cruzi positive blood donors (BD): Non-CC-BD (187 BD without CC with normal electrocardiogram [ECG] and left ventricular ejection fraction [LVEF]); CC-Non-Dys-BD (46 BD with CC with abnormal ECG but normal LVEF); and 153 matched serum-negative controls. This cohort was composed of 97 patients with severe CC (CC-Dys). We used Kruskall-Wallis and Spearman’s correlation to test hypothesis of associations, assuming a two-tailed p<0.05 as significant.Results The Gal-3 level was 12.3 ng/mL for Non-CC-BD, 12.0 ng/mL for CC-Non-Dys-BD, 13.8 ng/mL for controls, and 15.4 ng/mL for CC-Dys. LVEF<50 was associated with higher Gal-3 levels (p=0.0001). In our linear regression adjusted model, we found association between Gal-3 levels and echocardiogram parameters in T. cruzi-seropositive subjects. In CC-Dys patients, we found a significant association of higher Gal-3 levels (≥15.3 ng/mL) and subsequent death or heart transplantation in a 5-year follow-up (Hazard ratio – HR 3.11; 95%CI 1.21–8.04; p=0.019).Conclusions In ChD patients, higher Gal-3 levels were significantly associated with severe forms of the disease and more long-term mortality, which means it may be a useful means to identify high-risk patients. (Arq Bras Cardiol. 2021; 116(2):248-256)     

Enhancement of chemotactic factor-stimulated neutrophil oxidative metabolism by leukotriene B4

Leukotriene B4 (LTB4) is a potent primary stimulator of neutrophil chemotaxis, aggregation, and degranulation and induces superoxide production at higher concentrations. In order to determine whether LTB4 modulates neutrophil responses to oxidative stimuli, human neutrophils (PMNs) were incubated with LTB4 prior to stimulation with f-Met-Leu-Phe (fMLP, 10(-7) mol/L), opsonized zymosan (OZ, 250 micrograms/mL), or phorbol myristate acetate (PMA, 32 nmol/L). Superoxide (O2-) production by stimulated PMNs was assessed by the superoxide dismutase-inhibitable reduction of cytochrome c. LTB4 alone did not stimulate O2- production in concentrations below 10(-7) mol/L and had no effect on the O2- assay. In the concentration range of 10(-12) to 10(-8) mol/L, LTB4 did not alter O2- release induced by OZ or PMA. In contrast, LTB4-treated cells demonstrated enhanced O2- production following exposure to fMLP, and in the presence of 10 nmol/LLTB4, generated 180% +/- 41% of O-2 quantities produced by control cells (n = 23). Enhancement was LTB4 dose-dependent, was maximal in the range of 1 to 10 nmol/L LTB4, was not reversed by removal of the lipid from the medium prior to fMLP stimulation, and was not dependent on the presence of Ca++ or Mg++ in the suspending medium. Chemiluminescence of fMLP-stimulated neutrophils was increased to 323% of controls in neutrophils preincubated with 10 nmol/L LTB4. Unlike augmentation of oxidative responses to fMLP seen with other degranulating stimuli, enhancement by LTB4 was not correlated with an increase in 3H-fMLP receptor binding. These results indicate that, in addition to its primary effects on neutrophil function, LTB4 modulates PMN oxidative responses to the chemotactic peptide and, thus, may amplify the release of oxygen metabolites at inflammatory foci.     

Long-term outcome after intensive therapy with etoposide, melphalan, total body irradiation and autotransplant for acute myeloid leukemia

Intensive therapy and autologous blood and marrow transplantation (ABMT) is an established post-remission treatment for acute myeloid leukemia (AML), although its exact role remains controversial and few data are available regarding longer-term outcomes. We examined the long-term outcome of patients with AML transplanted at a single center using uniform intensive therapy consisting of etoposide, melphalan and TBI. In all, 145 patients with AML underwent ABMT: 117 in first remission, 21 in second remission and seven beyond second remission. EFS and OS were significantly predicted by remission status (P<0.0001). For transplantation in first remission, 8 year EFS and OS were 55% (95% CI, 44-64%) and 62% (95% CI, 50-72%), respectively. By multivariate analysis, only age (P=0.04) and cytogenetic risk group (P=0.006) influenced OS. For patients transplanted in second remission, 8 year EFS and OS were 30% (95% CI, 9-55%) and 36% (95% CI, 13-60%), respectively. No pre-transplant variables significantly predicted outcome. None of the seven patients who underwent ABMT beyond second remission or in early relapse were long-term survivors. ABMT can provide long-term antileukemic control for patients with AML in first remission. For patients in second remission approximately 30% can achieve cure with ABMT, and this option may be preferable to alternate donor allogeneic stem cell transplantation.     

Erythropoietin-specific cell cycle progression in erythroid subclones of the interleukin-3-dependent cell line 32D [published erratum appears in Blood 1993 Jun 1;81(11):3168]

Recently, a variety of growth factor-dependent subclones of the murine interleukin-3 (IL-3)-dependent cell line 32D have been isolated. These subclones include those dependent for growth on erythropoietin (Epo) (32D Epo), granulocyte-macrophage colony-stimulating factor (GM-CSF) (32D GM), or granulocyte colony-stimulating factor (G-CSF) (32D G). 32D Epo1.1 is a revertant of 32D Epo and is capable of growing in IL-3. These cell lines express the differentiation program appropriate to the specific growth factor and depend on the growth factors not only for proliferation but also for survival. To determine how the signal for proliferation is triggered by various growth factors, we examined the DNA histograms and the expression of cell cycle-specific genes in the different cell lines. The cell cycle-specific genes analyzed were myc (early G1), myb (late G1), and the structural genes for the calcium- binding protein 2A9 (middle G1) and histone H3 (G1-S boundary). The DNA histogram analysis of cells in the logarithmic phase of growth showed that approximately 40% of 32D, 32D GM, 32D G, and 32D Epo1.1 (growing in IL-3) were cells with a 2N DNA content (and therefore in G0/G1), and another 40% have a DNA content intermediate between 2N and 4N (in S phase). In contrast, 32D Epo and 32D Epo1.1 (growing in Epo) had fewer cells in the G0/G1 phase of the cell cycle compared with the number of cells that were in the S phase (19% to 31% v 69% to 78%, respectively). Because all the cell lines have comparable doubling times (15 to 18 hours), the cell distribution among the phases of the cell cycle is proportional to the length of the phase. Therefore, cells growing in IL- 3 (32D and 32D Epo1.1), GM-CSF (32D GM), or G-CSF (32D G) progress along the cycle in a manner typical of previously reported nontransformed cell lines. In contrast, cells growing in Epo (32D Epo or 32D Epo1.1) spend relatively less time in G0/G1 and correspondingly more time in S. These data were confirmed by the analysis of the tritiated thymidine (3H-TdR) suicide rate and of the expression of cell cycle-specific genes. The 32D and 32D Epo1.1 cells growing in IL-3 had a suicide rate of congruent to 50%, whereas the suicide rate of 32D Epo and 32D Epo1.1 growing in Epo was higher than 75%.(ABSTRACT TRUNCATED AT 400 WORDS)     

Prospective randomized trial of antibiotic prophylaxis in acute leukemia

Patients undergoing initial remission induction chemotherapy for acute leukemia in a protected environment unit were randomly assigned to parenteral antibiotic prophylaxis or oral and parenteral antibiotic prophylaxis. Complete remissions were obtained in 82 percent of the 45 patients receiving oral and parenteral antibiotic prophylaxis and 76 percent of the 41 patients receiving parenteral antibiotic prophylaxis. Approximately 20 percent of the patients in both groups have had a continuous complete remission for more than five years. The episodes of fever of unknown origin and major infection were significantly more common in patients receiving parenteral antibiotic prophylaxis, although the episodes of local infection were similar in both groups. The duration of remission and survival was similar in both groups. Hence, the oral and parenteral antibiotic regimen was more effective for infection prophylaxis, but had no effect on response to antileukemic chemotherapy.     

The effectiveness of rubidazone in hairy cell leukemia (leukemic reticuloendotheliosis).

Two patients with hairy cell leukemia treated with the anthracycline antibiotic rubidazone are presented. One achieved a complete remission and the other a good partial hematologic and bone marrow remission. Neither has relapsed (at 20 and 13 mo, respectively), and neither has been retreated. Intensive supportive measures were required during the prolonged myelosuppression that followed treatment. The relative youth of the patients (ages 24 and 39 yr) may have contributed to their ability to survive until normal marrow recovered. Chemotherapy should not be employed in the initial management of hairy cell leukemia. However, if life-threatening granulocytopenia and thrombocytopenia occur secondary to bone marrow replacement by leukemic cells, and improvement does not occur using alternative methods of therapy, consideration could be given to chemotherapy with rubidazone. Facilities for intensive supportive care should be available.     

Myeloablative conditioning regimens for AML allografts: 30 years later

During the last three decades, several myeloablative conditioning regimens have been used for AML allografts. In this review, we systematically examine the data from studies reporting on myeloablative conditioning regimens for AML allografts. High-dose busulfan combined with cyclophosphamide (BuCy) and cyclophosphamide in combination with total body irradiation (CyTBI) are the two most commonly used conditioning regimens for AML allografts. From the available data, there are no significant differences in survival with these two regimens. A small benefit of decreased relapse rate with CyTBI is counterbalanced by a nonsignificant increase in treatment-related mortality. The incidence of veno-occlusive disease is significantly higher in patients treated with BuCy. Therapeutic monitoring of busulfan was not reported in any of the studies comparing the regimens. Either of the regimens can be used for AML allografts, and the choice may ultimately depend on local availability and expertise. Further improvements may be possible from modifications of the standard regimens. Data from these latter studies seem to be encouraging, but are not based on comparative randomized trials.     

p16INK4A and p15INK4B gene deletions in primary leukemias

The 9p21 locus has been deleted at a high frequency in a wide variety of tumors. Recently, two genes, p16INK4A and p15INK4B (also called MTS1 and MTS2), have been localized in close proximity at the 9p21 locus, encoding cyclin-dependent kinases 4/6 inhibitors of relative molecular mass 16 kD and 15 kD, respectively and also found to be deleted at a high frequency in tumor cell lines. We analyzed p16INK4A and p15INK4B genes in 178 cases of primary leukemias including 81 cases of chronic lymphocytic leukemia (CLL), seven of hairy cell leukemia (HCL), seven of chronic myelogenous leukemia (CML), 43 of acute myelogenous leukemia (AML), 27 of acute lymphoblastic leukemia (ALL), and 13 of myelodysplastic syndrome (MDS) by Southern blot analyses. The ALL cases showed a relatively high frequency of homozygous deletions (22%, 6 of 27) at the p16INK4A gene locus. Interestingly, of the six cases with p16INK4A homozygous deletions, only three showed homozygous deletions at the p15INK4B gene. In 81 CLL patients, we detected one homozygous and five heterozygous deletions at both the p16INK4A and p15INK4B genes and two heterozygous deletions at the p16INK4A gene alone. Deletion of these two genes in AML cases is relatively low (9%). We did not detect deletions in any of the MDS, HCL, and CML cases examined. Sequence analyses of p16INK4A gene of six CLL cases with heterozygous deletion at this locus showed a 27-bp deletion at the splice acceptor site of intron 1 in one case and changes in the coding sequence in three other cases. The data presented in this report showed that (1) p16INK4A and p15INK4B genes are preferentially deleted homozygously in ALL and heterozygously in CLL cases with frequent mutation in the second allele, and (2) p16INK4A gene appears to be more frequently deleted than p15INK4B gene.     

Allogeneic or autologous bone marrow transplantation (BMT) for non-Hodgkin's lymphoma (NHL): results of a provincial strategy. Ontario BMT Network, Canada

In 1986, the bone marrow transplant centers in Ontario agreed to a strategy for the treatment of patients with NHL. Suitable patients would undergo autotransplant but be referred for allotransplant if they had persistent marrow involvement or an inadequate marrow/stem cell harvest. Data of all patients were recorded in a database. We reviewed this database to compare these transplant modalities with respect to overall survival, rate of relapse and treatment-related mortality. Between January 1986 and August 1997, 429 patients underwent BMT for NHL - 385 autotransplants and 44 allotransplants. Sixty-eight percent of patients received their transplant for aggressive NHL, while the others had indolent lymphoma. Three-year actuarial survival did not differ between allogeneic and autologous BMT: 71% vs 62%, respectively (P = 0.5330 by log-rank testing). Three-year actuarial rate of relapse was lower after allotransplant than autotransplant: 6% vs 41%, respectively (P = 0.0006 by log-rank testing). Treatment-related mortality was higher after allotransplant than autotransplant: 23% vs 6%, respectively (P = 0.001 by chi2 analysis). For further comparison, autotransplant patients were randomly matched 2:1 with the allotransplant patients for age +/- 5 years, disease status at BMT, disease histology, and year of BMT. In the matched comparison, survival did not differ (relative risk of death after allotransplant: 0.711 (95% CI: 0.309-1.637)). Relapse rate was significantly lower in the allotransplant group (relative risk of relapse for allotransplant: 0.190 (95% CI: 0.043-0.834)) and treatment-related mortality was not significantly different (relative risk for allotransplant: 1.425 (95% CI: 0.527-3.851)). In conclusion, a review of a provincial strategy for treatment of NHL, shows that survival is not different after allogeneic or autologous BMT, but the rate of relapse is lower after allotransplant. These data support continuing the current provincial strategy.