Methylation analysis of the DAPK1 gene in imatinib-resistant chronic myeloid leukemia patients.

Death-associated protein kinase-1 (DAPK1) is a pro-apoptotic gene that induces cellular apoptosis in response to internal and external apoptotic stimulants. The silencing of DAPK1 can result in uncontrolled cell proliferation, indicating that it may have a role in tumor suppression. DAPK1 activity can be inhibited by the cytosine methylation that occurs in its promoter region. These methylation changes in the promoter region of DAPK1 have been reported in a range of solid and hematological malignancies. In the present study, DAPK1 methylation was investigated in chronic myeloid leukemia patients (n=43) using bisulfite conversion followed by methylation-specific polymerase chain reaction. The present study included a number of patients who were identified to be resistant to the common chemotherapeutic agent imatinib (STI571, Gleevec®, Glivec®), exhibiting at least one mutation in the breakpoint cluster region-Abelson murine leukemia (BCR-ABL) gene. Thus, the patients in the present study were divided into two groups according to their response to imatinib therapy: Non-resistant (n=26) and resistant (n=17) to imatinib. Resistant patients were characterized by the presence of single or multiple mutations of the BCR-ABL gene: i) T315I, ii) M351T, iii) E255K, iv) T315I and M351T or v) T315I, M351T and E255K. The present study identified that: i) The incidence of DAPK1 methylation was significantly higher in the resistant patients compared with the non-resistant patients; ii) the extent of resistance varied between mutation types; and iii) there was no DAPK1 methylation in any of the healthy controls. These findings indicate that DAPK1 methylation may be associated with a signaling pathway for imatinib resistance in chronic myeloid leukemia.

Impact of genetic variations of the CYP1A1, GSTT1, and GSTM1 genes on the risk of coronary artery disease.

Carcinogenic and toxic molecules produce DNA adducts that contribute to the development of atherosclerosis. Genetic polymorphisms of xenobiotic-detoxified enzymes, which control the level of DNA adducts, may affect both enzymatic activity and individual susceptibility to coronary artery disease (CAD). In this study we investigated the effects of genetic polymorphisms of the CYP1A1*2C, GSTT1, and GSTM1 enzymes on CAD risk in a Turkish population. Genotypes were determined for 132 CAD patients and 151 healthy controls by the polymerase chain reaction/restriction fragment length polymorphism method. There were no significant differences between patients and controls in terms of CYP1A1, GSTT1, and GSTM1 genotypes. Analysis of the possible interactions between the genotypes, after adjustment for the risk factors, demonstrated that individuals carrying CYP1A1 variant GSTT1 null genotypes had an 8.907-fold increased CAD risk compared to their wild status (p<0.05). We suggest that genetic polymorphisms of xenobiotic-metabolizing enzymes could play an important role in CAD. Therefore, CYP1A1 and GSTM1 polymorphisms should be considered as important parameters for the prediction of CAD.

Effects of antioxidants on post-thawed bovine sperm and oxidative stress parameters: antioxidants protect DNA integrity against cryodamage.

This study was conducted to determine the effects of methionine, inositol and carnitine on sperm (motility, abnormality, DNA integrity and in vivo fertility) and oxidative stress parameters (lipid peroxidation, total glutathione and antioxidant potential levels) of bovine semen after the freeze-thawing process. Nine ejaculates, collected with the aid of an artificial vagina twice a week from each Simmental bovine, were included in the study. Each ejaculate, splitted into seven equal groups and diluted in Tris-based extender containing methionine (2.5 and 7.5 mM), carnitine (2.5 and 7.5 mM), inositol (2.5 and 7.5 mM) and no additive (control), was cooled to 5 °C and then frozen in 0.25 ml straws. Frozen straws were then thawed individually at 37 °C for 20s in a water bath for the evaluation. The extender supplemented with 7.5 mM doses of carnitine and inositol led to higher subjective motility percentages (61.9±1.3% and 51.3±1.6%) compared to the other groups. The addition of methionine and carnitine at doses of 2.5 and 7.5 mM and inositol at doses of 7.5mM provided a greater protective effect in the percentages of total abnormality in comparison to the control and inositol 2.5 mM (P < 0.001). As regards CASA motility, 7.5 mM carnitine (41.6±2.9% and 54.2±4.9%) and inositol (34.9±2.0% and 47.3±2.2%) caused insignificant increases in CASA and total motility in comparison to the other groups. All of the antioxidants at 2.5 and 7.5 mM resulted in lower sperm with damaged DNA than that of control, thus reducing the DNA damage (P < 0.05). No significant differences were observed in CASA progressive motility and sperm motion characteristics among the groups. In fertility results based on 59-day non-returns, no significant differences were observed in non-return rates among groups. As regards biochemical parameters, supplementation with antioxidants did not significantly affect LPO and total GSH levels in comparison to the control group (P > 0.05). The maintenance of AOP level in methionine 2.5 mM was demonstrated to be higher (5.06±0.38 mM) than that of control (0.96±0.29 mM) following the freeze-thawing (P < 0.001). Supplementation with these antioxidants prior to the cryopreservation process protected the DNA integrity against the cryodamage. Furthermore, future research should focus on the molecular mechanisms of the antioxidative effects of the antioxidants methionine, carnitine and inositol during cryopreservation.

Association of CYP1A1 and glutathione S-transferase polymorphisms with male factor infertility.

OBJECTIVE: To examine whether a relationship exists between genetic polymorphisms of glutathione S-transferase (GST) M1 and T1, CYP1A1(*)2C, and male factor infertility. DESIGN: Genetic polymorphism analysis, case-control study. SETTING: University research laboratory and andrology clinic. PATIENT(S): One hundred ten men with infertility and 105 healthy fertile men were recruited for the study. INTERVENTION(S): Physical examination of the genitalia of patients, scrotal colored Doppler ultrasound examination, and blood sampling were performed for DNA extraction and genotyping. MAIN OUTCOME MEASURE(S): CYP1A1(*)2C, GSTM1, and GSTT1 polymorphism genotypes were determined by polymerase chain reaction and restriction fragment length polymorphism methods. Seminal parameters were analyzed. RESULT(S): There were significant differences between infertility and GSTM1, CYP1A1(*)2C genotypes by univariate analyses. A subject carrying CYP1A1 Val/Val or CYP1A1 Ile/Val in association with GSTM null genotype has 6.90 times more risk to be infertile than a subject carrying CYP1A1 Ile/Ile in association with GSTM1 wild-type genotype (odds ratio: 6.90, 95% confidence interval: 2.29-19.3). No correlation was found between the seminal parameters and the genetic variability. CONCLUSION: Our results suggest that genetic polymorphisms of xenobiotic-metabolizing enzymes could play an important role in infertility.

CYP1A1, GST gene polymorphisms and risk of chronic myeloid leukemia.

PRINCIPLES: Associations between polymorphisms for genes encoding enzymes involved in biotransformation of xenobiotics and susceptibility to several cancers have been shown in several studies. The aim of the present study is to investigate the influence of cytochromes P450 (CYP450) 1A1*2C and Glutathione S-transferases (GSTs) (T1 and M1) gene polymorphisms in susceptibility to chronic myeloid leukaemia (CML). METHODS: The frequency of CYP1A1 Ile/Val alleles and of GSTT1 and GSTM1 homozygous deletions was examined in 107 patients with CML and 132 healthy controls by PCR and/or PCRRFLP methods using blood samples. RESULTS: The frequency of CYP1A1 Val allele was found to be 19.2% in CML patients and 4.4% for controls, indicating that persons carrying this allele had an increased risk of CML (OR = 5.10, 95% CI: 2.60-9.97). The frequency of individuals carrying the GSTT1 null genotype was higher among CML patients (40.2%) compared to controls (19.2%) (OR = 2.82, 95% CI: 1.58-5.05; p <0.001). Therefore, GSTT1 present genotype may be a protective factor for CML. Although GSTM1 null genotype frequency was slightly higher in the patient group (44.9%) than in the controls (42.3%), this difference was not statistically significant (OR = 1.11, 95% CI: 0.66-1.86; p = 0.693). Individuals with GSTM1 null genotypes without the T allele have a 5.981 higher risk for CML than those who have the T allele. CONCLUSIONS: This data suggests that polymorphic CYP1A1 and GSTT1 genes appear to affect susceptibility to CML.

Does telomere length affect blood pressure?

Telomeres--tandem repeats at the ends of mammalian chromosomes--serve as clocks that pace cellular aging in vitro and in vivo and they may be a major determinant of human aging, not only at the cellular level but also at the organ and perhaps systemic levels. In industrialized nations, pulse pressure rises with age, and this might serve as a phenotype of biologic aging of the vasculature. In this study, investigators explored the relationship between telomere length in white blood cells and systolic/diastolic and pulse pressures. Telomere lengths of 37 female volunteers who were 50 years of age were measured with the fiber fluorescence in situ hybridization technique. With the use of Spearman's correlation coefficient, no relationship was found between pulse pressure, systolic blood pressure, diastolic blood pressure, body mass index, and telomere length. The results suggest that telomere length is not an indicator of blood pressure dynamics.

Infertility in a man with oligoasthenoteratozoospermia associated with nonrobertsonian translocation t(9;15)(p10;q10).

OBJECTIVE: To analyze an unusual nonrobertsonian translocation t(9;15)(p10;q10) found in an infertile man with oligoasthenoteratozoospermia who had a normal phenotype. DESIGN: Case report with a review of scientific literature. SETTING: Academic research environment. PATIENT(S): Infertile man with oligoasthenoteratozoospermia but otherwise apparently healthy. INTERVENTION(S): Peripheral blood lymphocytes were obtained for karyotyping, and metaphases were studied by the GBG fluorescence in situ hybridization (FISH) procedure. MAIN OUTCOME MEASURE(S): Physical examination, semen analysis, GBG banding, and FISH procedure. RESULT(S): The semen analysis revealed oligoasthenoteratozoospermia. The lymphocytic karyotype detected a translocation t(9;15)(p10;q10), and FISH procedure showed that the derived chromosome had a chromosome 15 centromere. CONCLUSION(S): The association of unusual translocation with male factor infertility was described. To our knowledge no such association has been described previously in men whose clinical manifestation is only infertility.

Is telomere length one of the determinants of reproductive life span?

The mechanism of final cessation of the reproductive life span has not been solved yet. It is generally assumed that the most important factor is ovarian follicular reserve. In ovaries at intrauterine period, a major factor that determines the number of the primordial follicle is the mitotic ability as well as the number of primordial germ cells, which migrate to gonadal ridge. The telomere length is one factor that determines the number of mitosis of the cell. The differences between the telomere lengths of same aged healthy women reflect the difference of the telomeres of the primordial germ cells at the intrauterine period. Women with long telomeres supposedly have had their primordial germ cells at the beginning of life with long telomeres. So, these cells should have had more mitotic division and more follicle numbers in the ovaries than the short ones. The aim of this study was to analyse the relation of the reproductive life span and telomere length. The telomere lengths of 37 women volunteers aged 50 years were measured by fiber FISH technique. A positive correlation was found between reproductive life span and the telomere length.