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DNA Integrity (dna + integrity)
Kinds of DNA Integrity Selected AbstractsImproved Comet assay for the assessment of UV genotoxicity in Mediterranean sea urchin eggsENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 5 2008Sarah Nahon Abstract Gametes and embryos of broadcast spawners are exposed to a wide range of chemical and physical stressors which may alone, or in conjunction, have serious consequences on reproductive outcomes. In this study, two Mediterranean echinoid species, Paracentrotus lividus and Sphaerechinus granularis, were chosen as models to study the genotoxicity of UV radiation (UVR) on the eggs of broadcast-spawning marine invertebrates. The single cell gel electrophoresis, or Comet assay, was successfully adapted to assess DNA strand breakage in sea urchin eggs. The results demonstrated that the genetic material of sea urchin eggs is susceptible to environmentally realistic UV exposure. The induction of DNA damage in the irradiated unfertilized eggs suggests that the previously described defense mechanisms in sea urchin eggs do not completely protect the egg's DNA against UV toxicity. Taken together, our results suggest that UV-impairment of the genetic integrity of the eggs might have a role in postfertilization failures and abnormal embryonic development. Although both species were vulnerable to UVR, embryonic development was less dramatically impaired in P.Lividus. This observation supports the postulation that species inhabiting shallower environments possess more efficient mechanisms to overcome UV-induced DNA alterations. The present demonstration of the utility and sensitivity of the Comet assay to evaluate DNA integrity in eggs from marine invertebrates opens new perspectives for monitoring the long-term effects of environmental exposure on populations and for the routine screening of substances for genotoxicity in marine systems. Environ. Mol. Mutagen., 2008. © 2008 Wiley-Liss, Inc. [source] Folate, colorectal carcinogenesis, and DNA methylation: Lessons from animal studiesENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 1 2004Young-In Kim Abstract Folate, a water-soluble B vitamin and cofactor in one-carbon transfer, is an important nutritional factor that may modulate the development of colorectal cancer (CRC). Epidemiologic and clinical studies indicate that dietary folate intake and blood folate levels are inversely associated with CRC risk. Collectively, these studies suggest an , 40% reduction in the risk of CRC in individuals with the highest dietary folate intake compared with those with the lowest intake. Animal studies using chemical and genetically predisposed rodent models have provided considerable support for a causal relationship between folate depletion and colorectal carcinogenesis as well as a dose-dependent protective effect of folate supplementation. However, animal studies also have shown that the dose and timing of folate intervention are critical in providing safe and effective chemoprevention; exceptionally high supplemental folate levels and folate intervention after microscopic neoplastic foci are established in the colorectal mucosa promote, rather than suppress, colorectal carcinogenesis. These animal studies, in conjunction with clinical observations, suggest that folate possesses dual modulatory effects on carcinogenesis depending on the timing and dose of folate intervention. Folate deficiency has an inhibitory effect, whereas folate supplementation has a promoting effect on the progression of established neoplasms. In contrast, folate deficiency in normal epithelial tissues appears to predispose them to neoplastic transformation, and modest levels of folate supplementation suppress the development of tumors in normal tissues. Notwithstanding the limitations associated with animal models, these studies suggest that the optimal timing and dose of folate intervention must be established for safe and effective chemoprevention in humans. Folate is an important factor in DNA synthesis, stability, and integrity, the repair aberrations of which have been implicated in colorectal carcinogenesis. Folate may also modulate DNA methylation, which is an important epigenetic determinant in gene expression (an inverse relationship), in the maintenance of DNA integrity and stability, in chromosomal modifications, and in the development of mutations. A mechanistic understanding of how folate status modulates colorectal carcinogenesis further strengthens the case for a causal relationship and provides insight into a possible chemopreventive role of folate. Environ. Mol. Mutagen. 44:10,25, 2004. © 2004 Wiley-Liss, Inc. [source] Accumulation and DNA damage in fathead minnows (Pimephales promelas) exposed to 2 brominated flame-retardant mixtures, Firemaster® 550 and Firemaster® BZ-54ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2010Jonathan S. Bearr Abstract Firemaster® 550 and Firemaster® BZ-54 are two brominated formulations that are in use as replacements for polybrominated diphenyl ether (PBDE) flame retardants. Two major components of these mixtures are 2,3,4,5-tetrabromo-ethylhexylbenzoate (TBB) and 2,3,4,5-tetrabromo-bis(2-ethylhexyl) phthalate (TBPH). Both have been measured in environmental matrices; however, scant toxicological information exists. The present study aimed to determine if these brominated flame-retardant formulations are bioavailable and adversely affect DNA integrity in fish. Fathead minnows (Pimephales promelas) were orally exposed to either FM 550, FM BZ54, or the nonbrominated form of TBPH, di-(2-ethylhexyl) phthalate (DEHP) for 56 d and depurated (e.g., fed clean food) for 22 d. At several time points, liver and blood cells were collected and assessed for DNA damage. Homogenized fish tissues were extracted and analyzed on day 0 and day 56 to determine the residue of TBB and TBPH and the appearance of any metabolites using gas chromatography-electron-capture negative ion mass spectrometry (GC/ECNI-MS). Significant increases (p,<,0.05) in DNA strand breaks from liver cells (but not blood cells) were observed during the exposure period compared with controls, although during depuration these levels returned to control. Both parent compounds, TBB and TBPH, were detected in tissues at approximately 1% of daily dosage along with brominated metabolites. The present study provides evidence for accumulation, metabolism, and genotoxicity of these new formulation flame retardants in fish and highlights the potential adverse effects of TBB- and TBPH-formulated fire retardants to aquatic species. Environ. Toxicol. Chem. 2010;29:722,729. © 2009 SETAC [source] Azidothymidine causes functional and structural destruction of mitochondria, glutathione deficiency and HIV-1 promoter sensitizationFEBS JOURNAL, Issue 11 2002Tokio Yamaguchi Mitochondrial functional and structural impairment and generation of oxidative stress have been implicated in aging, various diseases and chemotherapies. This study analyzed azidothymidine (AZT)-caused failures in mitochondrial functions, in redox regulation and activation of the HIV-1 gene expression. We monitored intracellular concentrations of ATP and glutathione (GSH) as the indicators of energy production and redox conditions, respectively, during the time-course experiments with U937 and MOLT4 human lymphoid cells in the presence of AZT (0.05 mg·mL,1) or H2O2 (0.01 mm) for 15,25 days. Mitochondrial DNA integrity and NF-,B-driven HIV-1 promoter activity were also assessed. ATP concentration began to decrease within several days after exposure to AZT or H2O2, and the decrease continued to reach 30,40% of the normal level. However, decline of GSH was detectable after a retention period for at least 5,6 days, and progressed likewise. PCR analyses found that mitochondrial DNA destruction occurred when the ATP and GSH depletion had progressed, detecting a difference in the deletion pattern between AZT and H2O2 -treated cells. The GSH decrease coincided with HIV-1 promoter sensitization detected by enhanced DNA binding ability of NF-,B and induction of the gene expression upon H2O2 -rechallenge. Our results suggest that, in the process of AIDS myopathy development, AZT or oxidative agents directly impair the energy-producing system of mitochondria, causing dysfunction of cellular redox control, which eventually leads to loss of the mitochondrial DNA integrity. The mechanism of cellular redox condition-mediated NF-,B activation is discussed. [source] Altering DNA base excision repair: Use of nuclear and mitochondrial-targeted N -methylpurine DNA glycosylase to sensitize astroglia to chemotherapeutic agents,GLIA, Issue 14 2007Jason F. Harrison Abstract Primary astrocyte cultures were used to investigate the modulation of DNA repair as a tool for sensitizing astrocytes to genotoxic agents. Base excision repair (BER) is the principal mechanism by which mammalian cells repair alkylation damage to DNA and involves the processing of relatively nontoxic DNA adducts through a series of cytotoxic intermediates during the course of restoring normal DNA integrity. An adenoviral expression system was employed to target high levels of the BER pathway initiator, N -methylpurine glycosylase (MPG), to either the mitochondria or nucleus of primary astrocytes to test the hypothesis that an alteration in BER results in increased alkylation sensitivity. Increasing MPG activity significantly increased BER kinetics in both the mitochondria and nuclei. Although modulating MPG activity in mitochondria appeared to have little effect on alkylation sensitivity, increased nuclear MPG activity resulted in cell death in astrocyte cultures treated with methylnitrosourea (MNU). Caspase-3 cleavage was not detected, thus indicating that these alkylation sensitive astrocytes do not undergo a typical programmed cell death in response to MNU. Astrocytes were found to express relatively high levels of antiapoptotic Bcl-2 and Bcl-XL and very low levels of proapoptotic Bad and Bid suggesting that the mitochondrial pathway of apoptosis may be blocked making astrocytes less vulnerable to proapoptotic stimuli compared with other cell types. Consequently, this unique characteristic of astrocytes may be responsible, in part, for resistance of astrocytomas to chemotherapeutic agents. © 2007 Wiley-Liss, Inc. [source] Sperm DNA integrity in cancer patients: the effect of disease and treatmentINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 6 2009O. Ståhl Summary As oncological treatment might impair the patients' fertility, male cancer patients are offered to cryopreserve semen prior to treatment. Impaired sperm DNA quality is associated with reduced fertility, and in case of assisted reproduction, sperm DNA integrity may have an impact on choice of method. Therefore, we have assessed sperm DNA integrity in cancer patients, comparing pre- and post-treatment quality. Sperm DNA integrity was investigated in cryopreserved semen from 121 cancer patients, the predominating diagnoses were germ cell cancer (GCC) and Hodgkin's lymphoma (HL). Post-treatment samples, with a median follow-up of 3 years, were analysed for 58 of the men, allowing a pre- and post-treatment analysis on an individual basis. Sperm DNA integrity was assessed using the Sperm Chromatin Structure Assay and expressed here as the DNA Fragmentation Index (DFI%). One hundred and thirty-seven fertile men served as controls. Before treatment, GCC (n = 84) and HL (n = 18) patients had higher DFI% than controls (n = 143) with a mean difference of 7.7 (95% CI 3.2,8.8) and 7.0 (95% CI 2,12), respectively. The same trend was observed for other cancer diagnoses, but without reaching statistical significance (mean difference 3.6, 95% CI ,1.2 to 8.4). No increase was seen in DFI% comparing pre- and post-treatment semen, regardless of treatment modality. A moderate elevation of DFI% was observed in cryopreserved semen from cancer patients. Oncological treatment, generally, did not induce any increase in DFI. These findings should be considered when discussing the utilization of pre-treatment cryopreserved semen vs. post-treatment fresh sperm in cancer patients undergoing assisted reproduction. [source] Relationship between seminal ascorbic acid and sperm DNA integrity in infertile menINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 6 2006Gyun Jee Song Summary Ascorbic acid has recently been reported to protect sperm DNA from the damage induced by exogenous oxidative stress in vitro. But, there is no report on seminal ascorbic acid and sperm DNA fragmentation in infertile men. In this study, we asked whether sperm DNA damage correlates with seminal ascorbic acid levels. Sperm DNA fragmentation index (DFI) was analysed in 75 men by flow cytometry after acridine orange staining. We also measured the levels of seminal plasma ascorbic acid and total antioxidant capacity. Abnormal sperm DNA integrity (DFI , 30%) was observed in 12% of the patients with normal semen parameters and in 52% of the patients with abnormal semen parameters. There were significant correlations between the level of DFI and conventional semen parameters including sperm count, motility and morphology (r = ,0.29, ,0.55 and ,0.53 respectively; p < 0.05). Seminal ascorbic acid level was significantly lower in the patients with leucospermia than the patient with normal semen parameters. Interestingly, a significantly greater percentage of men with abnormal DFI were observed in the patients with low levels of seminal ascorbic acid compared with those with normal or high levels of ascorbic acid (59% vs. 33%, p < 0.05). Men with insufficient seminal ascorbic acid frequently have sperm DNA damage. [source] Dietary zinc, copper and selenium, and risk of lung cancerINTERNATIONAL JOURNAL OF CANCER, Issue 5 2007Somdat Mahabir Abstract Zinc, copper and selenium are important cofactors for several enzymes that play a role in maintaining DNA integrity. However, limited epidemiologic research on these dietary trace metals and lung cancer risk is available. In an ongoing study of 1,676 incident lung cancer cases and 1,676 matched healthy controls, we studied the associations between dietary zinc, copper and selenium and lung cancer risk. Using multiple logistic regression analysis, the odds ratios (OR) and 95% confidence intervals (CI) of lung cancer for all subjects by increasing quartiles of dietary zinc intake were 1.0, 0.80 (0.65,0.99), 0.64 (0.51,0.81), 0.57 (0.42,0.75), respectively (p trend = 0.0004); similar results were found for men. For dietary copper, the ORs and 95% CI for all subjects were 1.0, 0.59 (0.49,0.73), 0.51 (0.41,0.64), 0.34 (0.26,0.45), respectively (p trend < 0.0001); similar reductions in risk and trend were observed by gender. Dietary selenium intake was not associated with risk, except for a significant inverse trend (p = 0.04) in men. Protective trends (p < 0.05) against lung cancer with increased dietary zinc intake were also found for all ages, BMI > 25, current smokers, pack-years ,30, light drinkers and participants without emphysema. Increased dietary copper intake was associated with protective trends (p < 0.05) across all ages, BMI, smoking and vitamin/mineral supplement categories, pack-years ,30 and 30.1,51.75 and participants without emphysema. Our results suggest that dietary zinc and copper intakes are associated with reduced risk of lung cancer. Given the known limitations of case,control studies, these findings must be interpreted with caution and warrant further investigation. © 2006 Wiley-Liss, Inc. [source] Inhibitory effect of apigenin on benzo(a)pyrene-mediated genotoxicity in Swiss albino miceJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 12 2006Tajdar Husain Khan Apigenin, a bioflavonoid, is abundantly present in fruits and vegetables and possesses potential chemopreventive properties against a wide variety of chronic diseases. In this study we investigated the anti-genotoxic effects of apigenin against a known genotoxicant, benzo(a)pyrene (B(a)P) (125 mg kg,1 orally) toxicity in Swiss albino mice. B(a)P administration led to induction of cytochrome P-450 (CYP), aryl hydrocarbon hydroxylase (AHH) and DNA strand breaks (P < 0.001), which was suppressed by apigenin (2.5 and 5 mg kg,1 orally) dose dependently (P < 0.001). B(a)P-induced depletion in the level of reduced glutathione (GSH), quinone reductase (QR) and glutathione-S-transferase (GST) was also shown to be restored by apigenin pre-treatment (P < 0.001). A simultaneous significant and dose-dependent reduction was noted in DNA strand breaks and in-vivo DNA damage (P < 0.001), which gives some insight into restoration of DNA integrity in modulator groups. These results strongly support the protective nature of apigenin against B(a)P-induced toxicity. [source] A host species-informative internal control for molecular assessment of African swine fever virus infection rates in the African sylvatic cycle Ornithodoros vectorMEDICAL AND VETERINARY ENTOMOLOGY, Issue 4 2009A. D. S. BASTOS Abstract African swine fever virus (ASFV) infection in adult Ornithodoros porcinus (Murry 1877, sensuWalton 1979) ticks collected from warthog burrows in southern and East Africa was assessed using a duplex genomic amplification approach that is informative with respect to the invertebrate host species and infecting sylvatic cycle virus. DNA extracted from individual ticks was used as template for the simultaneous amplification of a C-terminal 478-bp ASFV p72 gene region and a ,313-bp fragment of the tick mitochondrial 16S rRNA gene, under optimized reaction conditions. Within-warthog burrow infection rates ranged from 0% to 43% using this approach, and phylogenetic analysis of 16S gene sequences revealed the presence of three geographically discrete O. porcinus lineages, but no support for subspecies recognition. False negatives are precluded by the inclusion of host species-informative primers that ensure the DNA integrity of cytoplasmically located genome extracts. In addition, infection rate estimates are further improved as false positives arising from carry-over contamination when performing a two-step nested polymerase chain reaction are negated by the one-step approach. Phylogenetic comparison of full-length virus gene sequences with the partial C-terminal p72 gene target confirmed the epidemiological utility of the latter in a sylvatic setting. The method is therefore of particular value in studies assessing the prevalence and diversity of ASFV in relation to the African sylvatic tick vector and holds potential for investigating the role of alternative tick species in virus maintenance and transmission. [source] Xenobiotic activity in serum and sperm chromatin integrity in European and inuit populationsMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 4 2008Tanja Krüger Abstract Lipophilic persistent organic pollutants (POPs) are ubiquitous in the environment and suspected to interfere with hormone activities and reproduction. In previous studies we demonstrated that POP exposure can affect sperm DNA integrity and differences between Inuits and Europeans in sperm DNA integrity and xenobiotic activity were observed. The aim of this study was to investigate possible relations between human sperm chromatin integrity and the xenobiotic serum activity of lipophilic POPs assessed as effects on the estrogen (ER), androgen (AR), and/or aryl hydrocarbon (AhR) receptors. Human sperm chromatin integrity was assessed as DNA fragmentation index (%DFI) and high DNA stainability (%HDS) using the flow cytometric sperm chromatin structure assay (SCSA). Xenobiotic receptor activities were determined using chemically activated luciferase gene expression (CALUX) assay. The study included 53 Greenlandic Inuits and 247 Europeans (Sweden, Warsaw (Poland) and Kharkiv (Ukraine)). A heterogeneous pattern of correlations was found. For Inuits, ER and AhR activities and %DFI were inversely correlated, whereas a positive correlation between AR activity and %DFI was found for Europeans. In contrast, no correlation between receptor activities and %HDS was observed for Inuits but for Europeans positive and negative correlations were observed between ER and AR activities and %HDS, respectively. We suggest that the different patterns of xenobiotic serum activities, in combination with diet associated factors and/or genetics, might be connected to the observed differences in sperm chromatin integrity between the Inuits and Europeans. Mol. Reprod. Dev. 75: 669,680, 2008. © 2007 Wiley-Liss, Inc. [source] Evaluation of zeta and HA-binding methods for selection of spermatozoa with normal morphology, protamine content and DNA integrityANDROLOGIA, Issue 1 2010S. H. Razavi Summary Sperm selection parameters based on morphology and motility for ICSI might not be relevant to chromatin integrity. Thus sperm selection based on sperm characteristics has been suggested. Therefore, the aim of this study was to evaluate the efficiency of the zeta and hyaluronic acid (HA) sperm selection procedures with neat semen, for recovering spermatozoa with normal morphology, protamine content and DNA integrity in infertile men. Semen samples from 77 infertile couples were assessed during this study. Semen analysis was carried out according to World Health Organization criteria. Protamine content, DNA integrity and sperm morphology were assessed by chromomycin A3, sperm chromatin dispersion and Papanicolaou staining respectively. The results show that both HA and zeta methods were efficient to recover spermatozoa with normal morphology and protamine content. In terms of the latter parameters, there was no superiority between the two procedures. However, in terms of DNA integrity, the zeta method was more efficient compared with the control and HA procedure and no significant difference was observed between HA and the controls. Therefore, the zeta method appears to be a suitable procedure to recover spermatozoa with normal DNA integrity. [source] Assessment of sperm quality, DNA integrity and cryopreservation protocols in men diagnosed with testicular and systemic malignanciesANDROLOGIA, Issue 6 2009T. M. Said Summary Men diagnosed with malignancy are often referred for semen banking to preserve their fertility prior to cancer treatment. The chances of cancer patients for achieving future fecundity will be determined by the sperm quality including the integrity of the genomic material in the frozen samples. The objectives of this study were to compare the sperm quality and DNA integrity in men diagnosed with testicular and systemic malignancies before receiving treatment and to identify the optimum cryopreservation protocol for their samples including a remote semen collection option. In comparison with fertile donors, patients with testicular malignancies had significantly lower sperm concentration, while both testicular and systemic malignancy patients had significantly lower sperm motility and cryosurvival rates. In addition, the SCSA defined DNA fragmentation index was significantly higher in patients with testicular and systemic malignancies compared with fertile donors. It was noted that the extent of deterioration in sperm quality and DNA integrity seen in cancer patients did not reach the previously defined statistical threshold for impaired fertility. Freezing spermatozoa with the seminal plasma offers the highest protection against cryo-injury. Nevertheless, remote semen collection can still be used as it yields adequate results. [source] Human sperm DNA integrity in normal and abnormal semen samples and its correlation with sperm characteristicsANDROLOGIA, Issue 4 2009A. C. Varghese Summary Reports indicate an increase in the incidence of DNA fragmentation in male factor infertility and its role in the outcome of assisted reproductive techniques (ART). However, reports are conflicting between the relationships of sperm DNA integrity with conventional semen parameters. We examined the relationship between conventional sperm parameters and DNA integrity using acridine orange (AO) test. The study included 373 patients and 28 fertile volunteers. DNA normality was compared with semen parameters between the patient and donor populations. Significant correlations were noted between DNA normality and sperm concentration (r = 0.18, P = 0.000), motility (r = 0.21, P = 0.0001), rapid motility (0.19, P = 0.000), normal morphology by World Health Organization (r = 0.15, P = 0.019) and head defects (r = ,0.15, P = 0.023). A significant difference was noted in AO levels between donors and patients with asthenozoospermia (P = 0.002) and oligoasthenozoospermia (P = 0.001). A significant difference in DNA integrity was noted in samples having <30% and >30% normal morphology. A wide range of % DNA normality was observed in the patient group. Sperm assessment for DNA status using AO is reliable and shows good correlation with sperm count, motility and morphology. Assessment of sperm DNA status with AO staining may be helpful prior to ART. [source] EFFICACY OF SARGASSUM POLYCYSTUM (PHAEOPHYCEAE) SULPHATED POLYSACCHARIDE AGAINST PARACETAMOL-INDUCED DNA FRAGMENTATION AND MODULATION OF MEMBRANE-BOUND PHOSPHATASES DURING TOXIC HEPATITISCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 3 2007HB Raghavendran SUMMARY 1The aim of the present study was to assess the protective effect of Sargassum polycystum (sulphated polysaccharide) extract against paracetamol-induced DNA strand breaks and modulation of membrane-bound phosphatases, protein thiols and inorganic cations during toxic hepatitis. 2Seaweed extract (200 mg/kg per day for 21 days) was administered to male Wistar rats against paracetamol challenge. Serum and liver tissues were used to assess levels of ATPase, protein thiols and inorganic cations using atomic absorption spectroscopy. The fragmentation of DNA was assessed by agarose gel electrophoresis. 3Paracetamol induced intracellular stress, accompanied by changes in the structural and functional characteristics of liver cell membranes, which affected DNA integrity, membrane-bound ATPase and inorganic cations homeostasis. Rats intoxicated with paracetamol (800 mg/kg, i.p.) showed significant impairment in activities of total ATPase, Mg2+ -ATPase, Ca+ -ATPase and Na+/K+ -ATPase, with concomitant changes in the levels of tissue protein thiols and inorganic cations, such as Na+, K+ and Ca2+. These changes were prevented in animals pretreated with S. polycystum extract, which indicates that S. polycystum supplementation could exert some protective effect against paracetamol-induced toxic hepatitis in rats. 4The protective effect of the seaweed extract may be due to the presence of sulphated compounds that have free radical-scavenging activity. [source] A super sensor for DNA integrity: bigger is betterCLINICAL GENETICS, Issue 1 2001Susan E Andrew No abstract is available for this article. [source] | |||||||||||||