Overexpression of MCM2 in myelodysplastic syndromes: association with bone marrow cell apoptosis and peripheral cytopenia

Myelodysplastic syndromes (MDS) are characterized by proliferation and apoptosis of bone marrow cells. Minichromosome maintenance protein (MCM) 2, which is known to be essential for regulating DNA replication, has proven to have a pro-apoptotic effect in our recent study. Thus, to determine the role of MCM2 in MDS, real-time PCR, immunohistochemistry and in vitro analysis were performed. Our results showed higher MCM2 expression in MDS than in control and AML. Notably, there was no correlation between MCM2 and Ki67-labeling indices (LIs) in MDS, while MCM2 LIs were significantly correlated with cleaved caspase 3 LIs in MDS. In vitro analysis revealed that MCM2 overexpression induced apoptosis in HL60 cells. Furthermore, MDS bone marrow exhibited higher ratio of MCM2 and cleaved caspase 3 double-positive cells and the ratio was correlated with the degree of leukocytopenia. These results suggest that the up-regulated expression of MCM2 is associated with frequent apoptosis in MDS and may have an important role in the pathogenesis of MDS.     

Efficacy of rebamipide for low-dose aspirin-related gastrointestinal symptoms

Gastrointestinal symptoms are a problematic issue for patients who take low-dose aspirin for long time. We conducted a pilot study to investigate the efficacy of combination therapy with proton pump inhibitor and rebamipide. This was a prospective, randomized, double-blind, placebo-controlled cross-over study. All the subjects received aspirin 100 mg and omeprazole 20 mg. The subjects were divided into two groups and received either rebamipide 300 mg or placebo, which was prescribed for 4 weeks. The subjects were instructed to record their gastrointestinal symptom rating scale before the study and 1 and 4 weeks after beginning the protocol. These scores of the groups were compared before and after the treatment to evaluate the severity of their symptoms and the number of symptom items present in each group. For the subjects receiving rebamipide, the total prevalence of lower gastrointestinal symptoms was significantly different from the placebo group (p=0.0093) at week 4. No troublesome symptoms were observed in the rebamipide group. Inconclusion, the administration of rebamipide prevented the occurrence of troublesome symptoms, especially lower gastrointestinal symptoms, in patients taking aspirin and omeprazole. Rebamipide is a candidate drug for combination therapy with proton pump inhibitors to prevent low-dose aspirin-induced gastrointestinal symptoms.     

A Pilot Study of the Water Quality of the Yarra River, Victoria, Australia, Using In Vitro Techniques

A pilot study was initiated to provide the first information on the recombinant receptor-reporter gene bioassay (hormonal) activity of freshwaters in Victoria. The project involved the collection of water samples from six stations on the main stem of the Yarra River in and upstream of the city of Melbourne, Australia in April 2008 and April 2009. Samples were prepared for measurement of sample toxicity using a modified photobacterium test, genotoxicity using a high-throughput luminescent umu test method, and human and medaka estrogen receptor (hERα and medERα), retinoic acid receptor (RAR), aryl hydrocarbon receptor (AhR) and thyroid receptor (TR) assay activity using the relevant yeast-based bioassays. Most samples were only weakly or moderately toxic, with no relationship observed to location along the river. The data for 2008 suggests that at that time the Yarra River samples contained few compounds that were, in and of themselves, genotoxic. No estrogenic or thyroid, and <1?ng/L retinoic acid receptor activity was observed. AhR activity increased with progressed downstream. AhR activity was higher in April 2009 than at the same time in 2008, perhaps as a result of extensive bush fires in the catchment in the months immediately prior to sampling. About 24% of the total AhR activity observed was associated with suspended solids.     

Irradiation effect on osteoclastogenesis stimulated by breast cancer cells

To examine the effects of carbon ion and gamma ray irradiation on cancer-induced osteoclastogenesis, mouse calvaria MC3T3-E1 cells were cultured with conditioned medium from irradiated and non-irradiated MCF7 human breast cancer cells. The authors examined RANKL and OPG mRNA expression in osteoblastic MC3T3-E1 cells following treatment with conditioned MCF7 medium. Co-cultured MC3T3-E1 and bone marrow cells treated with conditioned medium from irradiated MCF7 cells showed decreased numbers of osteoclasts, assessed using TRAP staining. Conditioned medium from control MCF7 cells elevated the RANKL/OPG mRNA ratio in MC3T3-E1 cells; this effect was suppressed by carbon ion irradiation of the MCF7 cells. These data demonstrate that indirect interactions between breast cancer cells and MC3T3-E1 cells induce osteoclastogenesis in vitro through modulation of RANKL expression and that this process is suppressed by carbon ion irradiation.     

Replacement therapy for iron deficiency improves exercise capacity and quality of life in patients with cyanotic congenital heart disease and/or the Eisenmenger syndrome

Introduction

Iron deficiency is common in cyanotic congenital heart disease (CHD) and results in reduced exercise tolerance. Currently, iron replacement is advocated with limited evidence in cyanotic CHD. We investigated the safety and efficacy of iron replacement therapy in this population.

Methods

Twenty-five iron-deficient cyanotic CHD patients were prospectively studied between August 2008 and January 2009. Oral ferrous fumarate was titrated to a maximum dose of 200 mg thrice-daily. The CAMPHOR QoL questionnaire, 6 minute walk test (6MWT) and cardiopulmonary exercise testing were conducted at baseline and after 3 months of treatment.

Results

Mean age was 39.9 ± 10.9 years, 80% females. Fourteen had Eisenmenger syndrome, 6 complex cyanotic disease and 5 Fontan circulation. There were no adverse effects necessitating termination of treatment. After 3 months of treatment, hemoglobin (19.0 ± 2.9 g/dL to 20.4 ± 2.7 g/dL, p < 0.001), ferritin (13.3 ± 4.7 μg/L to 54.1 ± 24.2 μg/L, p < 0.001) and transferrin saturation (17.8 ± 9.6% to 34.8 ± 23.4%, p < 0.001) significantly increased. Significant improvements were also detected in the total CAMPHOR score (20.7 ± 10.9 to 16.2 ± 10.4, p = 0.001) and 6MWT distance (371.7 ± 84.7 m to 402.8.0 ± 74.9 m, p = 0.001). Peak VO₂ remained unchanged (40.7 ± 9.2% to 43.8 ± 12.4% of predicted, p = 0.15).

Conclusion

Three months of iron replacement therapy in iron-deficient cyanotic CHD patients was safe and resulted in significant improvement in exercise tolerance and quality of life. Identification of iron deficiency and appropriate replacement should be advocated in these patients.     

Vulnerable plaque features on coronary CT angiography as markers of inducible regional myocardial hypoperfusion from severe coronary artery stenoses

Objective

We explored whether the presence of 3 known features of plaque vulnerability on coronary CT angiography (CCTA) – low attenuation plaque content (LAP), positive remodeling (PR), and spotty calcification (SC) – identifies plaques associated with greater inducible myocardial hypoperfusion measured by myocardial perfusion imaging (MPI).

Methods

We analyzed 49 patients free of cardiac disease who underwent CCTA and MPI within a 6-month period and were found on CCTA to have focal 70–99% stenosis from predominantly non-calcified plaque in the proximal or mid segment of 1 major coronary artery. Presence of LAP (≤30 Hounsfield Units), PR (outer wall diameter exceeds proximal reference by ≥5%), and SC (≤3 mm long and occupies ≤90° of cross-sectional artery circumference) was determined. On MPI, reversible hypoperfusion in the myocardial territory corresponding to the diseased artery was quantified both as percentage of total myocardium (RevTPD_ART) by an automatic algorithm and as summed difference score (SDS_ART) by two experienced readers. RevTPD_ART ≥ 3% and SDS_ART ≥ 3 defined significant inducible hypoperfusion in the territory of the diseased artery.

Results

Plaques in patients with RevTPD_ART ≥ 3% more frequently exhibited LAP (70% vs. 14%, p < 0.001) and PR (70% vs. 24%, p = 0.001) but not SC (55% vs. 34%, p = 0.154). RevTPD_ART increased from 1.3 ± 1.2% in arteries with LAP−/PR− plaques to 3.2 ± 4.3% with LAP+/PR− or LAP−/PR+ plaques to 8.3 ± 2.4% with LAP+/PR+ plaques (p < 0.001); SDS_ART showed a similar increase: 0.3 ± 0.7 to 2.3 ± 2.8 to 6.0 ± 3.8 (p < 0.001). Using the same LAP/PR categorization, there was a marked increase in the frequency of significant hypoperfusion as determined by both RevTPD_ART ≥ 3% (1/19 to 10/21 to 9/9, p < 0.001) and SDS_ART ≥ 3 (1/19 to 8/21 to 8/9, p < 0.001). LAP and PR, but not SC, were strong predictors of RevTPD_ART and SDS_ART in regression models adjusting for potential confounders.

Conclusions

Presence of low attenuation plaque and positive remodeling in severely stenotic plaques on CCTA is strongly predictive of myocardial hypoperfusion and may be useful in assessing the hemodynamic significance of such lesions.