Effect of cigarette smoking on clinical outcomes of hospitalized Chinese male smokers with acute myocardial infarction.

BACKGROUND: Smoking is known to be a strong risk factor for premature atherosclerosis, acute myocardial infarction (AMI) and sudden cardiac death. According to a cross-sectional survey conducted in 2000 - 2001 in China, the prevalence of smoking among the Chinese men was 60.2%, the highest prevalence in the world. Up to date, the relationship between smoking and AMI in Chinese male smokers is still unclear. This study analyzed the baseline characteristics for male smokers hospitalized with AMI and investigated the effect of cigarette smoking on their clinical outcomes. METHODS: A total of 890 men aged 18 years or over with AMI were prospectively recruited from 1 January 2007 to 31 December 2009 from Shanxi Provincial People's Hospital. Patients were grouped into smokers and nonsmokers. The relationships between baseline characteristics and clinical outcomes were tested using either the chi-square test for trend for discrete variables or analysis of variance for continuous variables. RESULTS: Smokers accounted for 66.7% (594), more than twice of nonsmokers (296 (33.3%)), and were averaged 7 years younger ((56.61 ± 11.44) vs. (63.61 ± 11.62) years, P < 0.001). Smokers had the higher rate of TIMI flow grade 2 or 3 after thrombolytic therapy (42.4% vs. 24.5%, P = 0.002), 1 vessel disease (25.5% vs. 14.5%, P = 0.003) than nonsmokers. Smokers had better in-hospital outcome with lower in-hospital mortality rate than nonsmokers (6.2% vs. 10.8%, P = 0.023). CONCLUSIONS: Male smokers suffered from AMI in this study presented an average of 7 years earlier than nonsmokers and were more than twice as likely to have AMI as nonsmokers in China. Smoking appeared to result in earlier infarction, especially ST elevated myocardial infarction in otherwise healthier patients who are likely to survive.

[The C46359T polymorphism of DNMT3B promoter gene and pathogenesis of acute leukemia].

OBJECTIVE: To explore the relationship between the polymorphism of C46359T in DNMT3B promoter and the pathogenesis of acute leukemia (AL). METHODS: PCR-RFLP and DNA sequencing were used to analyze the genotypic polymorphism C46359T of promoter in genomic DNA of bone marrow cells/blood lymphocytes from 160 patients with AL and 240 normal controls. RESULTS: In people of the Hans in China, genotypic frequencies of 2.5% (CT), 97.5% (TT) and 0 (CC) were statistically significant (P < 0.001) comparing with the genotype frequencies of 41.8% (CT), 23.2% (TT) and 35.0% (CC) in Caucasian in USA. The genotypic frequency of CT heterozygote in 160 AL patients was 10.6%, significantly higher than that in the control subjects (2.5%, P < 0.001), indicating that the CT heterozygote might be a more frequent phenomenon in AL. Compared with TT homozygote, CT heterozygote had a 4.669-fold increased risk of acute leukemia (OR = 4.669; 95% confidence interval 1.700-14.747). It was suggested that CT heterozygote was relative to the pathogenesis of AL. CONCLUSIONS: Different distribution of genotypes in different races, the CT heterozygote was relative to the pathogenesis of AL.

[Methylation status of multidrug resistance (mdr1) gene and its correlation with expression of mdr1 gene in patients with hematologic malignancies].

To investigate the correlation between methylation and expression of multidrug resistance (mdr1) gene, restriction endonuclease HpaII combined with competitive PCR technique was used to quantitatively detect the methylation status of two CCGG sites located at -110 and -50 bp (region I and II) up to the transcription start site in mdr1 promoter in 54 AL and 9 MM patients. Semi-quantitative RT-PCR was used to detect the expression level of mdr1 gene. The results showed that inverse correlation between methylation rate of either region or total methylation rate and expression of mdr1 gene was observed. The correlation in the region I (r = -0.64) was closer than that in the region II (r = -0.4). High expression rate of mdr1 ascended significantly in low methylation group (n = 36) (P < 0.001). In comparison with chemotherapy sensitive group (n = 8), the methylation rate in refractory AL patients (n = 16) was lower (P = 0.05) in the region I, P < 0.05 in the region II and total regions. Comparing with the untreated patients (n = 36), the methylation rate in the region I and total methylation rate were lower in the patients with chemotherapy (n = 14) (P < 0.05). The methylation rate in the region II was also decreased after chemotherapy, however, no statistical significance was shown (P > 0.05). Increased mdr1 expression level accompanying with decreased methylation rate after chemotherapy was found, although no significant difference was shown (P = 0.06). It is concluded that the expression level of mdr1 gene was associated with the methylation status of CCGG in -110 and -50 bp upstream to the transcription start site, especially the -110 site. In both the patients treated with chemotherapy and the refractory patients, the methylation level of mdr1 gene decreased relatively. The rising expression of mdr1 gene after chemotherapy was associated with the decrease of methylation level.

[The expression of DNA methyltransferase DNMT1, 3A and 3B in acute leukemia and myelodysplastic syndrome].

OBJECTIVE: To explore the relationship between methyltransferases and the pathogenesis of acute leukemia (AL) and the leukemic transformation of myelodysplastic syndromes (MDS). METHODS: Semi-quantitative RT-PCR method was used to detect the mRNA expression level of DNMT1, 3A and 3B in bone marrow cells from 75 patients with AL or MDS. RESULTS: There was no significant difference in mRNA expression level of DNMTs between a low-risk MDS group (n = 21) and a normal group. However, increased expression level of DNMT1, 3A and 3B was found in 47.6%, 47.6% and 42.9% of the patients in the low-risk group, respectively, if the upper limit of 80% of the normal controls was considered as the critical level. In high-risk MDS (n = 13), a more proportion of the cases with increased expression level of DNMTs were found, that was 53.8%, 76.9% and 92.3% respectively, and only expression level of DNMT3B was significantly higher than that in the low-risk MDS group (P < 0.01). In the AL group (n = 41) expression level of all the three subtypes was coordinately higher than that in the MDS group (P < 0.01), companying with a more frequency of 92.7%, 97.6% and 100%. Comparing with the AML group, a significantly increased expression level of DNMT1 (P < 0.01) with the same level of DNMT 3A and 3B was interestingly observed in the ALL group. CONCLUSIONS: It is possible that up-regulated DNMTs contribute to the pathogenesis of AL and the leukemic transformation of MDS, and DNMT3B might be the most important enzyme among the three subtypes.