BCR-ABL maintains resistance of chronic myelogenous leukemia cells to apoptotic cell death [published erratum appears in Blood 1994 Jun 15;83(12):3835]

Apoptosis is the major form of cell death associated with the action of chemotherapeutic agents on tumor cells, and therefore the expression of genes that interfere with apoptosis can have important consequences for the efficacy of therapeutic approaches. Here we show that K562, a chronic myelogenous leukemia (CML) cell line expressing the BCR-ABL fusion protein, are resistant to the induction of apoptosis by a number of agents and conditions. Antisense oligodeoxynucleotides corresponding to the translation start of bcr downregulate bcr-abl protein in these cells and render them susceptible to induction of apoptosis by chemotherapeutic agents or serum deprivation. Expression of a temperature sensitive v-Abl protein reverses the effects of the antisense oligonucleotides, such that the cells remain resistant to apoptosis at the permissive temperature. These data indicate that bcr- abl acts as an anti-apoptosis gene in CML cells and suggests that the effect is dependent on the abl kinase activity in this chimeric protein. Inhibition of bcr-abl to render CML cells susceptible to apoptosis can be combined with therapeutic drugs and/or treatment capable of inducing apoptosis to provide an effective strategy for elimination of these cells.     

A selective microRNA-based strategy inhibits restenosis while preserving endothelial function

Drugs currently approved to coat stents used in percutaneous coronary interventions donot discriminate between proliferating vascular smooth muscle cells (VSMCs) andendothelial cells (ECs). This lack of discrimination delays reendothelialization andvascular healing, increasing the risk of late thrombosis following angioplasty. Wedeveloped a microRNA-based (miRNA-based) approach to inhibit proliferative VSMCs, thuspreventing restenosis, while selectively promoting reendothelialization and preserving ECfunction. We used an adenoviral (Ad) vector that encodes cyclin-dependent kinase inhibitorp27^Kip1 (p27) with target sequences for EC-specific miR-126-3p at the3′ end (Ad-p27-126TS). Exogenous p27 overexpression was evaluated in vitro and in arat arterial balloon injury model following transduction with Ad-p27-126TS, Ad-p27(without miR-126 target sequences), or Ad-GFP (control). In vitro, Ad-p27-126TS protectedthe ability of ECs to proliferate, migrate, and form networks. At 2 and 4 weeks afterinjury, Ad-p27-126TS–treated animals exhibited reduced restenosis, completereendothelialization, reduced hypercoagulability, and restoration of the vasodilatoryresponse to acetylcholine to levels comparable to those in uninjured vessels. Byincorporating miR-126-3p target sequences to leverage endogenous EC-specific miR-126, weoverexpressed exogenous p27 in VSMCs, while selectively inhibiting p27 overexpression inECs. Our proof-of-principle study demonstrates the potential of using a miRNA-basedstrategy as a therapeutic approach to specifically inhibit vascular restenosis whilepreserving EC function.     

Reappraisal of optimal hemoglobin standards for female blood donors in Canada

BACKGROUND: A hemoglobin (Hb) standard of 115 g per L on the copper sulfate test has been in use by the Canadian Red Cross Society Blood Services for female blood donor predonation screening since 1989. STUDY DESIGN AND METHODS: To determine if this lowered Hb standard results in increased iron deficiency in repeat blood donors, a study was conducted to evaluate the performance of the copper sulfate test and predonation capillary and venous Hb assays in a population of female blood donors most at risk of developing iron deficiency. RESULTS: Of the 174 donors who were of childbearing age, who were not taking iron supplements, and who had made at least three blood donations per year, 45 (25.9%) were iron deficient, and 64 (36.8%) had reduced iron stores; only 65 (37.3%) had normal iron stores. This study showed that capillary blood is more likely to have a higher Hb concentration (3.2 +/− 7.8 g/L) than venous blood samples, which could affect the performance of predonation screening assays that are based on capillary blood samples at a given discriminating value. With an Hb standard of 115 g per L, both the copper sulfate and capillary Hb assays were not sensitive enough to screen for iron deficiency (sensitivity, 27% and 33%; specificity, 96% and 93%, respectively) and were comparable only to the performance of a venous Hb assay with a cutoff value of 110 g per L (sensitivity, 27%; specificity, 99%). In contrast, an Hb standard of 125 g per L in the copper sulfate test could achieve a more optimal sensitivity of 79 percent and specificity of 78 percent. CONCLUSION: This study supports the use of a higher Hb cutoff value of 125 g per L for female blood donors in the predonation fingerstick copper sulfate test.     

hs-CRP is a potential predictor of no-reflow in patients with AMI after emergency PCI

The paper aims to determine whether the inflammation,a powerful risk factor that has been demonstrated for the development of coronary artery disease,plays a role in no-reflow phenomenon in patients with acute myocardial infarction (AMI) after percutaneous coronary intervention (PCI).Methods We prospectively analyzed 656 patients with AMI after primary PCI.Based on post-PCI angiography data,patients were divided into two groups:the no-reflow group (TIMI=2,n =60) and the reflow group (TIMI=3,n =596).Results Our results showed that the inflammatory factors including leukocyte count (×109/L) (10.90±4.04 vs.9.12±2.98 P =0.002),hs-CRP (5.04±0.71 vs.4.70±0.75 P =0.001) and other factor platelet count (×109/L) (210.96±33.42 vs.196.41±46.06 P =0.033) in no-reflow group are significantly higher than those in reflow group,major adverse cardiac events happened in the patients with no-reflow are higher than in reflow patients no matter in hospital or at the end of follow-up.We also found the left ventricular ejection fraction (LVEF) dramatically decreased (58.65±9.34 vs.51.29±11.38,P＜0.001) and left ventricular end-diastolic dimension (LVEDD) significantly increased (49.94±6.75 mm vs.54.66±6.68mm,P＜0.001) in no-reflow patients at the end of follow-up.Conclusions Our results suggest that inflammation factors function in no-reflow phenomenon,and no-reflow is a serious complication after primary PCI which predicts poor left ventricular systolic functional recovery and mortality in patients with AMI.(J Geriatr Cardiol 2008;5:217-222)     

Alterations in the intrinsic properties of the GPIbalpha-VWF tether bond define the kinetics of the platelet-type von Willebrand disease mutation,Gly233Val

Platelet-type von Willebrand disease (PTVWD) is a bleeding disorder in which an increase of function mutation in glycoprotein Ibalpha (GPIbalpha), with respect to binding of von Willebrand factor (VWF), results in a loss of circulating high molecular weight VWF multimers together with a mild-moderate thrombocytopenia. To better ascertain the specific perturbations in adhesion associated with this disease state, we performed a detailed analysis of the kinetic and mechanical properties of tether bonds formed between PT-VWD platelets and the A1-domain of VWF. Results indicate that the GPIbalpha mutation, Gly233Val, promotes and stabilizes platelet adhesion to VWF at shear rates that do not support binding between the native receptor-ligand pair due to enhanced formation and increased longevity of the mutant tether bond (k0 off values for mutant versus native complex of 0.67 +/- 0.11 s-1 and 3.45 +/- 0.37 s-1, respectively). By contrast, the sensitivity of this interaction to an applied force, a measure of bond strength, was similar to the wild-type (WT) receptor. Although the observed alterations in the intrinsic properties of the GPIbalpha-VWF tether bond are comparable to those reported for the type 2B VWD, distinct molecular mechanisms may be responsible for these function-enhancing bleeding disorders, as interactions between the mutant receptor and mutant ligand resulted in a greater stability in platelet adhesion. We speculate that the enhanced cellular on-rate together with the prolongation in the lifetime of the mutant receptor-ligand bond contributes to platelet aggregation in circulating blood by permitting the formation of multiple GPIbalpha-VWF-A1 interactions.     

Histone H4 acetylation by immunohistochemistry and prognosis in relapsed acute lymphocytic leukaemia (ALL)

Histone H4 acetylation was examined by immunohistochemistry in patients with acute lymphocytic leukaemia (ALL) in first relapse. Univariate and multivariate models identified correlates of complete remission (CR) and overall survival (OS). No variables were associated with achievement of CR. In multivariate analysis, weak histone H4 acetylation [Hazard Ratio (HR) 2·20, 95% confidence interval (CI) 0·93–5·23, P = 0·07], shorter interval from diagnosis to relapse (<9 vs. 9–24 vs. >24 months) (HR 1·82, 95% CI 1·20–2·75, P = 0·005), and central nervous system involvement (HR 3·43, 95% CI 1·31–8·99, P = 0·01) were independent poor prognostic factors for OS. These data provide a rationale for the use of histone deacetylase inhibitors in the treatment of relapsed ALL.     

Family demography in a remote rural community in Zambia

A community survey was conducted in a remote rural area of Zambia by The Kasanka Trust whose aims in running a National Park are to include aid to the community living around its borders. Selected results have been extracted from a general report by the Kasanka Trust, including awareness of HIV infection and tuberculosis. The remarkable population dynamics found in this apparently impoverished, poorly served community is highlighted.     

Haemorrhagic shock encephalopathy syndrome presenting with myoglobinuria

An infant with haemorrhagic shock encephalopathy syndrome (HSES) who in addition presented with hyperpyrexia and myoglobinuria is reported. As rhabdomyolysis is a feature of heat stroke and malignant hyperthermia, the association of HSES with myoglobinuria supports the hypothesis that HSES may be a form of hypermetabolic state triggered by hyperthermia.