Ensayo del cometa como bioindicador de inestabilidad genómica en pacientes diabéticos hemodializados / Comet assay as a bioindicator of genomic instability in hemodialysis diabetic patients

Introducción: Procesos como la mutagénesis, la carcinogénesis y la teratogénesis son producto de la interacción de agentes de origen endógeno como exógeno que interactúan con la molécula de ADN en forma crónica produciendo rupturas en la doble hélice, y en cromosomas completos resultando en la inestabilidad genómica. El estrés oxidativo al que se encuentran sometidas las células al formarse las especies reactivas de oxígeno (ROS) y también las especies reactivas de nitrógeno (RNS), que pueden provenir de radicales producidos a consecuencia de la diabetes o en estados iniciales de la enfermedad renal crónica o como respuesta a procesos inflamatorios en estados avanzados de estas patologías, actúan como agentes genotóxicos endógenos.Objetivos: Esta investigación tuvo como objetivo determinar el daño basal en la molécula de ADN de pacientes diabéticos hemodializados, a través del ensayo del Cometa, como un bioindicador de inestabilidad genómica., durante seis meses de tratamiento. Materiales y métodos: Se planteó un estudio longitudinal prospectivo de cohorte para comparar los diferentes niveles de daño antes y durante los primeros seis del tratamiento de hemodiálisis. Se evaluó con el test del cometa o electroforesis de células individuales, el daño basal en muestras de sangre venosa de pacientes diagnosticados con Diabetes de tipo II como control negativo y en pacientes diabéticos con enfermedad renal crónica antes de iniciar el tratamiento de diálisis y luego durante el tratamiento. Se utilizó el test de t- Student para muestras independientes y emparejadas. Resultados: Se observó un aumento significativo de daño basal y oxidativo en el material genético de pacientes diabéticos con enfermedad renal crónica, comparados con los controles negativos (p< 0.005) y se observó, además, que el daño celular aumenta con el tratamiento de hemodiálisis (p<0.005). Conclusión: Los resultados obtenidos en esta investigación permiten concluir que el estrés oxidativo tiene un efecto genotóxico y que el nivel de daño genético es un buen bioindicador del avance de la enfermedad renal crónica y que la hemodiálisis induce a un aumento de daño a nivel del material genético, aumentando el riesgo de carcinogénesis.

Introduction: Processes such as mutagenesis, carcinogenesis and teratogenesis are the product of the interaction of agents of endogenous and exogenous origin that interact with the DNA molecule in a chronic way producing ruptures in the double helix, and in complete chromosomes resulting in genomic instability. The oxidative stress to which the cells are subjected when reactive oxygen species (ROS) and reactive nitrogen species (RNS) are formed, which may come from radicals produced as a result of diabetes or in initial stages of chronic kidney disease or in response to inflammatory processes in advanced stages of these pathologies, act as endogenous genotoxic agents. Objectives: This research aimed to determine the basal damage in the DNA molecule of hemodialyzed diabetic patients, through the Comet assay, as a bioindicator of genomic instability, during six months of treatment. Materials and methods: For this research, a prospective longitudinal cohort study was proposed to compare the different levels of genetic damage before and during the first six of hemodialysis treatment. Baseline damage was evaluated with the comet test or single cell electrophoresis, in venous blood samples from patients diagnosed with Type II Diabetes as a negative control and in diabetic patients with chronic kidney disease before starting dialysis treatment and then during treatment. Results: A significant increase in basal and oxidative damage was observed in the genetic material of diabetic patients with chronic kidney disease, compared to negative controls (p< 0.005) and it was also observed that cell damage increases with hemodialysis treatment (p<0.005). The t-Student test was used for independent and paired samples. Conclusion: The results obtained in this research allow us to conclude that oxidative stress has a genotoxic effect and that the level of genetic damage is a good bioindicator of the progression of chronic kidney disease and that hemodialysis induces an increase in damage at the level of the genetic material, increasing the risk of carcinogenesis.

Relevancia del metabolismo del folato en el contexto de enfermedades neurodegenerativas / Relevance of folate metabolism in neurodegenerative disorders

Introducción: Varias enfermedades neurodegenerativas están asociadas a alteraciones en el metabolismo del folato, lo que tiene sustanciales implicaciones fisiopatológicas, clínicas y terapéuticas potenciales. Objetivo: Reflejar la relevancia del metabolismo del folato para enfermedades neurodegenerativas, destacando su significación fisiopatológica y clínica, y sus implicaciones terapéuticas. Material y métodos: Se consultaron las bases de datos especializadas en busca de artículos publicados hasta marzo de 2020. Se emplearon descriptores específicos y operadores booleanos. Se empleó la estrategia de búsqueda avanzada para la selección de los artículos, teniendo en cuenta la calidad metodológica o validez de los estudios. Desarrollo: Fueron identificadas evidencias de asociación entre alteraciones del metabolismo del folato y enfermedades neurodegenerativas. Se han identificado variantes en genes que codifican enzimas involucradas en el metabolismo del folato, y modificaciones en patrones de metilación de ADN, asociadas al riesgo o a la gravedad clínica de las enfermedades de Alzheimer, Parkinson, Huntington, Temblor Esencial y Ataxia Espinocerebelosa tipo 2. Fueron encontradas asociaciones entre enfermedades neurodegenerativas y alteraciones en los niveles de metabolitos del folato, y la frecuencia de micronúcleos. Se han realizado varios estudios observacionales o experimentales que indican que la suplementación con ácido fólico y vitaminas B6 y B12, tiene utilidad terapéutica potencial en el contexto de enfermedades neurodegenerativas. Conclusiones: El metabolismo del folato es de relevancia fisiopatológica, clínica y terapéutica para enfermedades neurodegenerativas. El uso de estrategias dirigidas a restaurar los niveles normales de folatos o de co-factores enzimáticos involucrados en el metabolismo del folato, o a reducir la acumulación de homocisteína, tiene potenciales aplicaciones terapéuticas en el contexto de estas enfermedades(AU)

Introduction: Several neurodegenerative disorders are associated with alterations in folate metabolism, having essential physiopathological, clinical and therapeutic implications. Objective: To assess the relevance of folate metabolism in neurodegenerative disorders, highlighting its physiopathological, clinical and therapeutic significance. Material and Methods: Specialized biomedical databases were searched for studies published up to March 2020. Descriptors and Boolean operators were used. Advanced search strategy was used for the selection of articles, taking into account the methodological quality and validity of the studies. Results: Strong evidence of the association between folate metabolism and neurodegenerative disorders were identified. Enzyme-coding genes involved in folate metabolism and epigenetic DNA modifications associated with increased risk or disease severity in Alzheimer´s, Parkinson´s, and Huntington´s diseases, Essential Tremor, and Spinocerebellar ataxia type 2 were also identified. Associations between neurodegenerative disorders and altered levels of folate metabolites and the frequency of micronuclei were found. A number of observational and experimental studies have demonstrated that the supplementation with folic acid and vitamin B6 and B12 has therapeutic potential in the context of neurodegenerative disorders. Conclusions: Folate metabolism is of physiopathological, clinical and therapeutic relevance for neurodegenerative disorders. The use of strategies to normalize folate levels or enzyme cofactors involved in folate metabolism or to reduce homocysteine levels has potential therapeutic applications for these disorders(AU)

Anemia no diabetes mellitus gestacional: implicações na instabilidade genômica / Anemia in gestational diabetes mellitus: implications for genomic instability

Introdução: Evidências têm mostrado uma associação entre anemia e Diabetes Mellitus. Contudo, a relação entre anemia e Diabetes Mellitus Gestacional (DMG) ainda não está bem estabelecida, bem como sua repercussão na instabilidade genômica. Portanto, objetivou-se verificar a associação entre anemia e instabilidade genômica em mulheres com DMG atendidas em um hospital universitário. Métodos: Estudo transversal com mulheres apresentando diagnóstico de DMG que realizaram pré-natal no Hospital Universitário de Santa Maria (RS). Informações referentes ao DMG, anemia e suplementação de ferro foram obtidas nos prontuários. A instabilidade genômica foi avaliada pelo ensaio de citoma em micronúcleos em células bucais (BMCyt). Resultados: Das 44 gestantes avaliadas, 28,6% apresentaram anemia e 79,5% foram suplementadas com ferro. Das gestantes que realizaram suplementação, 75,0% não apresentaram anemia gestacional. Níveis de hemoglobina não se associaram com a instabilidade genomica (p > 0,05), mas foi observada uma associação entre brotos nucleares e os níveis de glicemia (r = 0,977; p = 0,003). Conclusão: Não foi verificado associação entre anemia e instabilidade genômica em mulheres com DMG.(AU)

Introduction: There is evidence of an association between anemia and diabetes mellitus. However, the relationship between anemia and gestational diabetes mellitus (GDM) remains to be established, as well as its impact on genomic instability. Therefore, we aimed to examine the association between anemia and genomic instability in women with GDM treated at a university hospital. Methods: A cross-sectional study of women with a diagnosis of GDM who received prenatal care at the University Hospital of Santa Maria, southern Brazil. Data on GDM, anemia, and iron supplementation were obtained from medical records. Genomic instability was assessed by the buccal micronucleus cytome (BMCyt) assay. Results: Of 44 pregnant women evaluated, 28.6% had anemia and 79.5% received iron supplementation; of the latter, 75.0% did not have gestational anemia. Hemoglobin levels were not associated with genomic instability (p > 0.05), but an association was found between nuclear buds and blood glucose levels (r = 0.977; p = 0.003). Conclusion: There was no association between anemia and genomic instability in women with GDM.(AU)

Avaliação dos efeitos genotóxicos da exposição ocupacional em frentistas atuantes em postos de gasolina no município de Santarém, Pará / Genotoxic effects of occupational exposure among gas station attendants in Santarem, Para, Brazil

Introdução: Profissionais frentistas encontram-se em situação de risco tóxico pela exposição constante aos vapores dos combustíveis. O benzeno, presente na gasolina, é considerado cancerígeno e prejudicial à saúde desses trabalhadores Objetivo: Avaliar os efeitos genotóxicos decorrentes da exposição ocupacional em células esfoliativas da mucosa oral de frentistas do município de Santarém, Pará; e determinar a taxa de adesão ao uso de equipamentos de proteção individual por esses colaboradores. Métodos: Um total de 126 frentistas, distribuídos em 6 grupos contendo indivíduos expostos foram comparados ao grupo controle utilizando a técnica do ensaio de micronúcleos em células da mucosa oral coradas com as técnicas de Feulgen/Fast-green. Resultados: Os frentistas apresentaram maior frequência de micronúcleos em relação ao grupo não exposto ao benzeno (p<0,01). Frentistas com hábito etílico apresentaram aumento significativo de micronúcleos (p<0,01), quando comparados aos frentistas abstêmios. Verificou-se que 100% dos profissionais entrevistados não fazem uso dos equipamentos de proteção. Conclusão: Constatou-se um aumento na presença de micronúcleos em células esfoliativas de frentistas em comparação ao grupo controle. Esse aumento é ainda maior quando o frentista ingere frequentemente bebidas alcoólicas.

Background: Gas station attendants are at high risk of poisoning due to continuous exposure to fuel fumes. Benzene, present in gasoline, is considered a carcinogen and harmful to the health of gas station attendants. Objective: To investigate genotoxic effects on exfoliated oral mucosa cells in association with occupational exposure among gas station attendants in Santarem, Para, Brazil, and to establish the rate of adherence to personal protective equipment (PPE). Methods: The results of the micronucleus test performed with oral mucosa cells stained by means of the Feulgen and Fast Green methods were compared between 126 exposed gas station attendants distributed across six groups and controls. Results: The frequency of micronuclei was higher among gas station attendants compared to the group not exposed to benzene (p<0.01). The frequency of micronuclei was significantly higher (p<0.01) among the gas station attendants who reported to drink alcohol compared to non-drinkers. None of the participants (0%) used PPE. Conclusion: The frequency of micronuclei in exfoliated oral mucosa cells was higher among gas station attendants compared to controls; frequency was even higher for the gas station attendants who reported to consume alcohol often

Occupational hazards, DNA damage, and oxidative stress on exposure to waste anesthetic gases / Riscos ocupacionais, danos no material genético e estresse oxidativo frente à exposição aos resíduos de gases anestésicos

Abstract Background and objectives The waste anesthetic gases (WAGs) present in the ambient air of operating rooms (OR), are associated with various occupational hazards. This paper intends to discuss occupational exposure to WAGs and its impact on exposed professionals, with emphasis on genetic damage and oxidative stress. Content Despite the emergence of safer inhaled anesthetics, occupational exposure to WAGs remains a current concern. Factors related to anesthetic techniques and anesthesia workstations, in addition to the absence of a scavenging system in the OR, contribute to anesthetic pollution. In order to minimize the health risks of exposed professionals, several countries have recommended legislation with maximum exposure limits. However, developing countries still require measurement of WAGs and regulation for occupational exposure to WAGs. WAGs are capable of inducing damage to the genetic material, such as DNA damage assessed using the comet assay and increased frequency of micronucleus in professionals with long-term exposure. Oxidative stress is also associated with WAGs exposure, as it induces lipid peroxidation, oxidative damage in DNA, and impairment of the antioxidant defense system in exposed professionals. Conclusions The occupational hazards related to WAGs including genotoxicity, mutagenicity and oxidative stress, stand as a public health issue and must be acknowledged by exposed personnel and responsible authorities, especially in developing countries. Thus, it is urgent to stablish maximum safe limits of concentration of WAGs in ORs and educational practices and protocols for exposed professionals.

Resumo Justificativa e objetivos Os Resíduos de Gases Anestésicos (RGA) presentes no ar ambiente das Salas de Operação (SO) são associados a riscos ocupacionais diversos. O presente artigo propõe-se a discorrer sobre exposição ocupacional aos RGA e seu impacto em profissionais expostos, com ênfase em danos genéticos e estresse oxidativo. Conteúdo Apesar do surgimento de anestésicos inalatórios mais seguros, a exposição ocupacional aos RGA ainda é preocupação atual. Fatores relacionados às técnicas anestésicas e estação de anestesia, além da ausência de sistema de exaustão de gases em SO, contribuem para poluição anestésica. Para minimizar os riscos à saúde em profissionais expostos, recomendam-se limites máximos de exposição. Entretanto, em países em desenvolvimento, ainda carece a mensuração de RGA e de regulamentação frente à exposição ocupacional aos RGA. Os RGA são capazes de induzir danos no material genético, como danos no DNA avaliados pelo teste do cometa e aumento na frequência de micronúcleos em profissionais com exposição prolongada. O estresse oxidativo também é associado à exposição aos RGA por induzir lipoperoxidação, danos oxidativos no DNA e comprometimento do sistema antioxidante em profissionais expostos. Conclusões Por tratar-se de questão de saúde pública, é imprescindível reconhecer os riscos ocupacionais relacionados aos RGA, inclusive genotoxicidade, mutagenicidade e estresse oxidativo. Urge a necessidade de mensuração dos RGA para conhecimento desses valores nas SO, especialmente em países em desenvolvimento, de normatização das concentrações máximas seguras de RGA nas SO, além de se adotarem práticas de educação com conscientização dos profissionais expostos.

Human papillomavirus and genome instability: from productive infection to cancer

Infection with high oncogenic risk human papillomavirus types is the etiological factor of cervical cancer and a major cause of other epithelial malignancies, including vulvar, vaginal, anal, penile and head and neck carcinomas. These agents affect epithelial homeostasis through the expression of specific proteins that deregulate important cellular signaling pathways to achieve efficient viral replication. Among the major targets of viral proteins are components of the DNA damage detection and repair machinery. The activation of many of these cellular factors is critical to process viral genome replication intermediates and, consequently, to sustain faithful viral progeny production. In addition to the important role of cellular DNA repair machinery in the infective human papillomavirus cycle, alterations in the expression and activity of many of its components are observed in human papillomavirus-related tumors. Several studies from different laboratories have reported the impact of the expression of human papillomavirus oncogenes, mainly E6 and E7, on proteins in almost all the main cellular DNA repair mechanisms. This has direct consequences on cellular transformation since it causes the accumulation of point mutations, insertions and deletions of short nucleotide stretches, as well as numerical and structural chromosomal alterations characteristic of tumor cells. On the other hand, it is clear that human papillomavirus-transformed cells depend on the preservation of a basal cellular DNA repair activity level to maintain tumor cell viability. In this review, we summarize the data concerning the effect of human papillomavirus infection on DNA repair mechanisms. In addition, we discuss the potential of exploiting human papillomavirus-transformed cell dependency on DNA repair pathways as effective antitumoral therapies.

The role and clinical significance of migration and invasion inhibitory protein in the de-velopment and progression of tumors / 中国肿瘤临床

Migration and invasion inhibitory protein(MIIP)inhibits cell proliferation,migration,and invasion,impeding tumorigenesis and tumor progression,by interacting with insulin-like growth factor binding protein 2(IGFBP2),histone deacetylase 6(HDAC6),p21 activated kinase 1(PAK1),epidermal growth factor receptor(EGFR),cell division cycle 20(CDC20),and topoisomerase.Recent studies revealed potential roles of MIIP in viral infection and cellular immunity.MIIP has become a research hotspot owing to its involvement in multiple signaling pathways and as a potential therapeutic target for tumors.This review summarizes the characteristics,functions, clinical significance,and possible pathogenic mechanisms of MIIP in multiple carcinomas.

Spontaneous chromatid break as clonal evolution in myelodysplastic syndrome patients / Quebra espontânea de cromátides como evolução clonal em pacientes com síndrome mielodisplásica

ABSTRACT Myelodysplastic syndrome (MDS) is a clonal hematopoietic stem cell disorder characterized by peripheral cytopenias due to ineffective erythropoiesis and an increased risk for evolving into acute myeloid leukemia (AML). Chromosomal abnormalities represent the most important marker of risk stratification for AML transformation. Chromatid break (chtb) is a discontinuity of a single chromatid. We report the case of a patient with MDS whose cytogenetic analysis showed spontaneous chromatid breakage (chrb): 46,XY,add(13)(q34),chtb(15)(q24) [3]/47,XY,chtb(2)(q22),del(5)(q35),del(7)(q32),+8,del(11q)(q23),del(q22)[cp17]. He was considered a high-risk patient due to the complex karyotype and the presence of chtb. We suggest that this chromosomal abnormality may be considered as a marker of genomic instability in MDS.

RESUMO A síndrome mielodisplásica (SMD) é uma desordem clonal das células-tronco hematopoiéticas caracterizada por citopenias periféricas devido à hematopoiese ineficaz e pelo aumento do risco de evolução para a leucemia mieloide aguda (LMA). As alterações cromossômicas representam o marcador mais importante da estratificação de risco para a transformação de LMA. Quebra das cromátides (chtb) é uma descontinuidade de uma única cromátide. Relatamos o caso de um paciente com SMD, cuja análise citogenética mostrou chtb espontâneo: 46,XY,add(13)(q34),chtb(15)(q24)[3]/47,XY,chtb(2)(q22),del(5) (q35),del(7)(q32),+8,del(11q)(q23),del(q22)[cp17]. O paciente foi considerado de alto risco devido ao cariótipo complexo e à presença de chtb. Sugerimos que essa anormalidade cromossômica possa ser considerada como marcador de instabilidade.

Non-homologous End Joining Inhibitor SCR-7 to Exacerbate Low-dose Doxorubicin Cytotoxicity in HeLa Cells

Among the genotoxic drug regimens, doxorubicin (DOX) is known for its high-dose side effects in several carcinomas, including cervical cancer. This study reports on testing the combined use of a DOX genotoxic drug and SCR-7 non-homologous end joining (NHEJ) inhibitor for HeLa cells. An in vitro DNA damaging assay of DOX was performed on plasmid and genomic DNA substrate. In vitro cytotoxicity was investigated using trypan blue dye exclusion, DNA metabolizing, and propidium iodide-based flow cytometric assays. DOX (between 20–100 μM) displayed clear DNA binding and interaction, such as the shearing and smearing of plasmid and genomic DNA. DNA metabolizing assay data indicate that HeLa lysate with DOX and SCR-7 treatment exhibited better in vitro plasmid DNA stability compared with DOX treatment alone. SCR-7 augmented the effects of low-dose DOX by demonstrating enhanced cell death from 15% to 50%. The flow cytometric data also supported that the combination of SCR-7 with DOX lead to a 23% increase in propidium iodide-based HeLa staining, thus indicating enhanced death. In summary, the inhibition of NHEJ DNA repair pathway can potentiate low-dose DOX to produce appreciable cytotoxicity in HeLa cells.

Base excision repair and targeted therapy strategies / 国际肿瘤学杂志

Base excision repair (BER) is an important pathway for DNA oxidative damage repair,and mutations in this pathway cause gene instability and increase cancer risk.A large number of studies have shown that abnormal expression of key proteins in the BER pathway in a variety of tumors,such as DNA glycosylase,apurinic/apyrimidinic endonuclease 1,DNA polymerase and so on.Single nucleotide polymorphisms of these proteins affect the repair activity of tumor cells,and are expected to be important indicators for the diagnosis,treatment and evaluation of prognosis.

Genomic instability and its detection technologies for clinical application in cancer patients / 中华检验医学杂志

Carcinogenesis is a multistep process that a couple of genes involve in the initiation of this disease.As a pivotal hallmark of cancer, the genomic instability ensues in which genetic alterations when this process was initialized and developed. With the increasing number of studies on genomic instability, the scientists pay more attentions on its biological function at post-genomic era. Genomic instability in various carcinomas is associated with broken telomere, gene modification, and contributes to the dysfunction of DNA damage and repair pathways.This review focus on the factors involved in genomic instability, as well the current detection methods of genomic instability and their clinical application.

Effects of CDT1 gene over-expression on cell apoptosis and cell cycle in irradiation-induced genomic instable liver cells / 中华放射医学与防护杂志

Objective To investigate the effect of CDT1 gene over-expression on the apoptosis and cell cycle distribution in liver cells with a characteristic of genomic instability induced by radiation(GIR).Methods Lentivirus particles were transferred into liver cells of GIR to up-regulate the expression of CDT1 gene.The apoptosis and the cell cycle were detected by flow cytometry (FCM).The expression changes of p53,ATM,ATR,Bcl-2,and Caspase-3 genes were analyzed by real-time fluorescence quantitative PCR.Results CDT1 gene was efficiently increased by the gene transfection(t =15.56,P ＜ 0.05).In the CDT1 over-expressed cells,while the apoptosis ratio was increased (t =4.19,P ＜ 0.05),the expressions of p53 and Bcl-2 gene were decreased (t =-4.21,-2.06,P ＜ 0.05),but the expression of ATM,ATR and Caspase-3 changed with no significant difference compared with control.Conclusions Over-expression of CDT1 could regulate genomic instability through apoptosis pathway and checkpoint independent of p53.

Genome Architecture and Its Roles in Human Copy Number Variation

Besides single-nucleotide variants in the human genome, large-scale genomic variants, such as copy number variations (CNVs), are being increasingly discovered as a genetic source of human diversity and the pathogenic factors of diseases. Recent experimental findings have shed light on the links between different genome architectures and CNV mutagenesis. In this review, we summarize various genomic features and discuss their contributions to CNV formation. Genomic repeats, including both low-copy and high-copy repeats, play important roles in CNV instability, which was initially known as DNA recombination events. Furthermore, it has been found that human genomic repeats can also induce DNA replication errors and consequently result in CNV mutations. Some recent studies showed that DNA replication timing, which reflects the high-order information of genomic organization, is involved in human CNV mutations. Our review highlights that genome architecture, from DNA sequence to high-order genomic organization, is an important molecular factor in CNV mutagenesis and human genomic instability.

Effects of HAVCR2 gene silence on apoptosis and cell cycle in the radiation-caused genomic instable liver cells / 中华放射医学与防护杂志

Objective To explore the effects of HAVCR2 siRNA on apoptosis and cell cycle in the radiation-caused genomic instable liver cells.Methods RNAi was used to inhibit HAVCR2 gene transcription.Cellular apoptosis and cell cycle distribution were detected by flow cytometry (FCM).Expression of p53 gene was assayed by real time fluorescence quantitative PCR.Results HAVCR2 gene was effectively inhibited by RNAi (t =19.21,P ＜ 0.05).After siRNA transferring,cell apoptosis (t =3.65,P ＜ 0.05) and p53 gene expression (t =4.82,P ＜ 0.05) were decreased,and G2-phase arrest was induced(t =-3.41,P ＜ 0.05).Conclusion HAVCR2 siRNA can decrease the generation of apoptosis in the genomic instable liver cells and blocks the cells at G2 phase.

Association of microsatellite instability and chronic obstructive pulmonary disorder in isocyanate-exposed population of Bhopal.

Context: Survivors of the Bhopal gas disaster still suffer from various respiratory ailments. We examined the effects of exposures among a cross-section of current residents suffering from COPD by ISSR-PCR. Aims: Molecular screening of the gas-affected population of Bhopal with COPD for microsatellite instability due to exposure of MIC. Settings and Design: The isocyanate-exposed population of Bhopal city suffering from chronic obstructive pulmonary disorder. Materials and Methods: Inter-(SSR) analysis was used to characterize microsatellite instability in 52 MIC victims of Bhopal, suffering from COPD using (CA) 8 RG and (CA) 8 R[Y-Q] primer. Statistical Analysis Used: Association analyses were performed using regression analysis. Results: The study on the MIC-affected population in Bhopal showed weak association between microsatellite instability and age (r = + 0.37); exposure distance from site (r = −0.44); and smoking status(r = + 0.12); while regression analysis of the above parameters displayed supporting evidence. Conclusions: The high prevalence of smoking coupled with aging and poor living habits threatens, to further increase COPD incidences among this population, highlighting the need for enhanced screening efforts.

The regional genomic instability induced by 60Co γ-rays in B16 cells transfected by GFP / 中华放射医学与防护杂志

Objective To detect the regional genomic instability of B16 cells treated with 60Co γ-rays by a green fluorescence protein (GFP)-based genomic instability reporting system.Methods Three groups were employed as non-transfection group,vector control group and transfection group.The GFP-marked reporter construct pCMV-EGFP2XhoI for regional genomic instability was successfully transfected into B16 cells using liposome.B16 cells were selected by screening of G418 with a series of concentrations and limiting dilution cultures to yield a single colony.B16 cells with the genomic instability report system were then irradiated by 60Co γ-rays at doses of 0,2 and 4 Gy.The regional genomic instability of B16 cellswas quantified by counting the number of cells with GFP expression.Results B-16 cell strain steadilyexpressing the GFP-based genomic instability reporting system was established successfully.GFP-positiveB16 cells were observed at 1 d after irradiation with 60Co γ-rays at doses of 2 and 4 Gy.Positive correlations between fluorescence intensity and dose and fluorescence intensity and time were also observed.The positive expression rate of GFP followed the increased of dose (F =36.55,36.76,P ＜ 0.05) and time (t =-3.27,-3.16,-4.26,-6.11,-7.17,P ＜ 0.05),and differences between groups were significant.The positive expression rate of GFP increased significantly at 3 d,and maximum expression was observed at 5 d(2.46 ± 0.24 and 3.82 ± 0.35).The level was tending towards stability.Spontaneous GFP expression at a ratio of 1/600 000 was observed in 0 Gy group after 2 weeks of culture.Conclusions The regional genomic instability of B16 cells induced by 60Co γ-rays can be detected using a GFP-labelled genomic instability reporter system.

Genomic instability in patients with type 2 diabetes mellitus on hemodialysis

OBJECTIVE: A previous study by our research group evaluated the levels of DNA damage using the comet assay in hemodialysis patients with type 2 diabetes mellitus. The same blood samples were also evaluated using the cytochalasin B micronucleus assay. A comparison of the results of the two assays is presented here. METHODS: Whole blood samples were collected from 22 type 2 diabetes mellitus patients on hemodialysis and from 22 control subjects. Samples were collected from patients early in the morning on Mondays, before the first weekly hemodialysis session. The cytokinesis-block micronucleus assay (CBMN) was used to evaluate genomic instability. RESULTS: The frequencies of micronuclei and nuclear buds were higher in patients than in controls (p-value = 0.001 and p-value < 0.001, respectively). There was a correlation between the frequency of micronuclei and DNA damage with the results of the comet assay (p-value < 0.001). The difference in the frequency of micronuclei and nuclear buds between patients and controls was more pronounced in the group with higher median comet values than in the group with lower comet values. CONCLUSIONS: Our results suggest that the increased rates of DNA damage as measured by the comet assay and influenced by the weekly routine therapy of these patients has a mutagenic effect, thereby increasing the risk of cancer in this group.

Genomic imbalances detected through array CGH in fetuses with holoprosencephaly / Instabilidades genômicas detectadas através de array CGH em fetos com holoprosencefalia

OBJECTIVE: Holoprosencephaly (HPE) is heterogeneous in pathogenesis, integrating genetic susceptibility with the influence of environmental factors. Submicroscopic aberrations may contribute to the etiology of HPE. Our aim was to report the molecular analysis of 4 fetuses with HPE and normal metaphase karyotype. METHOD: A whole genome BAC-array based Comparative Genomic Hybridization (array CGH) was carried out in fetal blood samples. All potential cytogenetic alterations detected on the arrays were matched against the known copy number variations databases. RESULTS: The array CGH analysis showed copy number gains and losses in all cases. We found a recurrent deletion in 15q14 (clone RP11-23J11) and in 15q22 (clone RP11-537k8) in 2 out 4 cases analyzed. We also observed submicroscopic gain in 6p21 in 3 out of 4 fetuses in nearby clones. All these regions were tested in known databases and no copy number variations have been described for them. CONCLUSION: This is the first report of molecular characterization through a whole genome microarray CGH of fetuses with HPE. Our results may contribute to verify the effectiveness and applicability of the molecular technique of array CGH for prenatal diagnosis purposes, and contributing to the knowledge of the submicroscopic genomic instability characterization of HPE fetuses.

OBJETIVO: Holoprosencefalia (HPE) é uma malformação heterogênea na patogênese, integrando a suscetibilidade genética com a influência de fatores ambientais. Aberrações submicroscópicas podem contribuir para a etiologia da HPE. Nosso objetivo foi relatar a análise molecular de 4 fetos com HPE e cariótipo normal. MÉTODO: Foi realizado um estudo descritivo prospectivo dos achados da técnica de hibridação genômica comparativa baseada em microarranjos utilizando BAC clones de ampla cobertura genômica (BAC-array CGH) em amostras sanguíneas de fetos portadores de holoprosencefalia e com cromossomos numericamente normais ao bandamento G. Todas as potenciais alterações citogenéticas detectadas foram comparadas com bancos de dados com variações do número de cópias conhecidas. RESULTADOS: A análise de array CGH evidenciou ganhos e perdas do número de cópias em todos os 4 casos. Foram encontradas deleções recorrentes em 15q14 (clone RP11-23J11) e em 15q22 (clone RP11-537k8) em 2 dos 4 casos analisados. Observou-se em 3 fetos ganho genômico na região 6p21 em clones próximos. Todas estas regiões não apresentaram variações do número de cópias descritas em bancos de dados conhecidos. CONCLUSÃO: Este é o primeiro relato de caracterização molecular através de um microarray CGH de fetos com HPE. Nossos resultados podem contribuir para verificar a eficácia e aplicabilidade da técnica molecular de array CGH para fins de diagnóstico pré-natal, contribuindo para o conhecimento da caracterização de instabilidades genômicas submicroscópicas de fetos com HPE.

Differential expression profile in the progeny of normal human liver cells irradiated by 60Co γ-rays / 中华放射医学与防护杂志

Objective To investigate the differential expression profile in the progeny of human liver cells surviving from ionizing radiation.Methods Complemental DNA gene chip was used to measure the transcriptional profile in progeny of HL-7702 cells exposed to 0, 2, 4, and 6 Gy of 60Co γ-rays, and the differentially expressed genes HAVCR2 and RAN were further identified by real-time PCR.Results The transcription level of 262 genes, 2746 genes and 3406 genes changed in the progeny of survival cells at 2, 4 and 6 Gy, respectively.A total of 71 common differentially expressed genes were screened, most of which were associated with transduction, cell cycle regulation, cellular immunity, cytoskeleton and movement, cell replication and repair mechanism.Conclusions Ionizing radiation could induce the expression changes of many genes, which might reveal the molecular mechanisms of gene expression in radiation induced genomic instability.

As vitaminas e minerais relacionados à estabilidade genômica e à proteção ao câncer / The vitamins and minerals related to genomic stability and cancer protection

Certain vitamins and minerals work in maintaining genomic stability, therefore showing a potential action in cancer prevention. The objective of this work is a literature review to ascertain the current status of knowledge on protective mechanisms against cancer, the evidence obtained from epidemiological studies and recommendations for dietary intake of micronutrients related to genomic stability: vitamins C, D, E, B6, B12, folate and calcium. A deficiency of folate, B6, B12 seems to cause chromosome breaks and micronucleus formation. Vitamins C and E have antioxidant action. Vitamin C has the ability to neutralize carcinogens and vitamin E protects the cell oxidizable substrates. Calcium and vitamin D are involved in regulation of cell proliferation and differentiation, induction of apoptosis and inhibition of angiogenesis. Epidemiological studies have shown increased risk for cancer at various sites associated with low intake of these vitamins and calcium.

Ciertas vitaminas y minerales actúan en la mantención de la estabilidad genómica, por lotanto, con potencial de acción en la prevención del cáncer. El objetivo de este trabajo es una revisión bibliográfica para conocer el estado actual del conocimiento sobre los mecanismos de protección contra el cáncer, las evidencias obtenidas en los estudios epidemiológicos y recomendaciones para la ingestión de micronutrientes relacionados con la estabilidad genómica: vitaminas C, D, E, B6, B12, ácido fólico y calcio. Las deficiencias de folato, B6, B12 aparentemente provocan rupturas cromosómicas y formación de micro-núcleos. Las vitaminas C y E pose en acción antioxidante. La vitamina C tiene capacidad de neutralizar los agentes carcinógenos y vitamina E protege los substratos oxidables de las células. Calcio y vitamina D están implicados en la regulación de la proliferación y diferenciación celular, la inducción de la apoptosis y la inhibición de la angiogénesis. Los estudios epidemiológicos han demostrado un mayor riesgo de cáncer endiferentes regiones asociadas a un bajo consumode estas vitaminas y calcio.

Determinadas vitaminas e minerais atuam na manutenção da estabilidade genômica, portanto, com potencial ação na prevenção do câncer. O objetivo deste trabalho é realizar uma revisão bibliográfica para verificar o estágio atual dos conhecimentos sobre os mecanismos de proteção ao câncer, as evidências obtidas nos estudos epidemiológicos e as recomendações para a ingestão dietética de micronutrientes relacionados à estabilidade genômica: vitaminas C, D, E, B6, B12, folato e cálcio. A deficiência de folato, B6 e B12 parece causar quebra no cromossomo e formação de micronúcleos. As vitaminas C e E tem ação antioxidante.A vitamina C tem habilidade em neutralizar substâncias carcinogênicas e a E protege os substratos oxidáveis das células. O cálcio e a vitamina D estão envolvidos na regulação da proliferação e diferenciação celular, indução da apoptose e inibição da angiongênese. Estudos epidemiológicos têm evidenciado maior risco para câncer em diversos sítios associado à baixa ingestão destas vitaminas e do cálcio.