16 resultados para Paraneoplastic syndromes

em Universidade Federal do Rio Grande do Norte(UFRN)


Relevância:

10.00% 10.00%

Publicador:

Resumo:

ARAUJO, Afranio Cesar de et al. Síndromes de polinização ocorrentes em uma área de Mata Atlântica, Paraíba, Brasil. Biotemas, Florianopolis, v. 4, n. 22, p.83-94, dez. 2009. Disponível em: . Acesso em: 04 out. 2010.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

studies using UV as a source of DNA damage. However, even though unrepaired UV-induced DNA damages are related to mutagenesis, cell death and tumorigenesis, they do not explain phenotypes such as neurodegeneration and internal tumors observed in patients with syndromes like Xeroderma Pigmentosum (XP) and Cockayne Syndrome (CS) that are associated with NER deficiency. Recent evidences point to a role of NER in the repair of 8-oxodG, a typical substrate of Base Excision Repair (BER). Since deficiencies in BER result in genomic instability, neurodegenerative diseases and cancer, it was investigated in this research the impact of XPC deficiency on BER functions in human cells. It was analyzed both the expression and the cellular localization of APE1, OGG1 e PARP-1, the mainly BER enzymes, in different NER-deficient human fibroblasts. The endogenous levels of these enzymes are reduced in XPC deficient cells. Surprisingly, XP-C fibroblasts were more resistant to oxidative agents than the other NER deficient fibroblasts, despite presenting the highest of 8-oxodG. Furthermore, subtle changes in the nuclear and mitochondrial localization of APE1 were detected in XP-C fibroblasts. To confirm the impact of XPC deficiency in the regulation of APE1 and OGG1 expression and activity, we constructed a XPC-complemented cell line. Although the XPC complementation was only partial, we found that XPC-complemented cells presented increased levels of OGG1 than XPC-deficient cells. The extracts from XPC-complemented cells also presented an elevated OGG1 enzimatic activity. However, it was not observed changes in APE1 expression and activity in the XPCcomplemented cells. In addition, we found that full-length APE1 (37 kDa) and OGG1- α are in the mitochondria of XPC-deficient fibroblasts and XPC-complemented fibroblasts before and after induction of oxidative stress. On the other hand, the expression of APE1 and PARP-1 are not altered in brain and liver of XPC knockout mice. However, XPC deficiency changed the APE1 localization in hypoccampus and hypothalamus. We also observed a physical interaction between XPC and APE1 proteins in human cells. In conclusion, the data suggest that XPC protein has a role in the regulation of OGG1 expression and activity in human cells and is involved mainly in the regulation of APE1 localization in mice. Aditionally, the response of NER deficient cells under oxidative stress may not be only associated to the NER deficiency per se, but it may include the new functions of NER enzymes in regulation of expression and cell localization of BER proteins

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Leptospirosis is a worldwide zoonosis of considerable medical and economical importance that affects humans in both urban and rural contexts, as well as domestic animals and wild fauna. Leptospira interrogans is the causative agent and is transmitted to humans by indirect contact with contaminated soil or water. The clinical syndromes include sub clinical infection, self-limited anicteric febrile illness, and severe and potentially fatal illness, known as Weil´s syndrome. In developed countries, leptospirosis is related to occupational or recreational activities while in developing countries, outbreaks occur during floods. In those regions, traditional strategies to prevent the transmission are difficulties to be implemented because of costs and lack of community acceptance. In addition, no efficient vaccine is available for human use. Several studies have suggested that chemoprophylaxis with doxycycline pre and post-exposure may be effective to prevent leptospirosis. Leptospirosis has been reported in rural areas of the State of Rio Grande do Norte, Brazil since 1985 in rice farmers who present the anicteric illness. The disease cause great social and economics impact. The study was conducted in São Miguel where an epidemic of leptospirosis in rice farmers was reported. The main objective was to determine the efficacy of doxycycline in preventing Leptospira exposure. A taxa de soroprevalência de leptospirose na população estudada antes e após a colheita foi de 14,2% (n=22) e de 16.6% (n=27) respectivamente. Anti-Leptospira serology was determined for 61 subjects in two instances, pre and post-exposure to potential contaminated water. There was an increased risk of 29.0 per cent in acquiring infection for individuals that did not use doxycycline. In addition, an increased risk of 30.0 % observed in farmers who did not use protection when exposed to Leptospira. The adhesion to preventive chemoprophylaxis was 55.7%. Therefore doxycycline, under specific circunstances appears to be an effective alternative to protect against leptosprirosis infection. A large sample composed of individuals to adhere to preventive therapy is needed to define time, dosage and length of use of doxycycline in this area

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Hypertensive syndromes in pregnancy (HSP) are configured as one of the major complications in the pregnancy and postpartum period and can lead premature newborn and subsequent hospitalization of the newborn to the Neonatal Intensive Care Unit (NICU). This study aimed to analyze the perceptions, meanings and feelings of mothers on the hypertensive syndromes in pregnancy and premature obstetric labor. The research was qualitative and has a theoretical methodological the Social Representations Theory(SRT) in the approach to the Central Nucleus Theory. The study included 70 women, mean age 29 years, predominantly school to high school, most of them married or in consensual union, primiparous and prevalence of cesarean delivery occurred between 32 and 37 weeks of pregnancy.The data were collected from may to december 2008 in the Maternity School Januário Cicco in Natal , and obtained through the following instruments for data collection: questionnaire including questions about socio-demographic status; the Free Words Association Test (FWAT) and and verbalized mental image construction used three stimuli: such as pregnancy with high blood pressure, preterm birth and NICU, and interview with the following guiding question: what it meant for you to have a pregnancy with high blood pressure and consequently the birth of a premature baby? Data analysis was performed using multi-method obtained from the data processing by EVOC (Ensemble Programmes Permettant L 'Analyze des Évocations) and ALCESTE (Analyse Lexicale par Contexte d'un Ensemble de Segment de Texte) and thematic analysis in categories. The results will be presented in four thematic units under the following representative universes: HSP, prematurity as a result of HSP, NICU and the social representations of mothers on the hypertensive disorder of pregnancy sequenced premature birth and hospitalization of the child in the NICU. The results obtained by multimethod analyses showed similar constructions and point to death as the central nucleus and negative aspects, coping strategies, need of care, knowledge about the disease, fragility and meanings of the NICU as peripheral elements. It is considered that the perceptions, meanings and feelings of puerperal women in relation to HSPs and to premature delivery are a negative social representation, with representational elements that may have influenced the adverse effects on the disease and its consequences. We suggest action on the peripheral elements of this representation, with adequate orientation, early diagnosis, effective conduct, receptive attitude on the part of the team, health promotion measures and effective public policies, in order to improve the care provided to puerperal women, making them feel welcome and minimizing their suffering

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The general aim of the research was to comprehend the Social Representations constructed by the man in the face of his companion s risk pregnancy caused by hypertensive syndromes. The study is of exploratory and descriptive character in a qualitative approach developed at two public maternity hospitals, both located in Natal-RN, with 65 men whose wives had undergone high-risk pregnancy. The project was submitted to the Ethics on Research Committee of the Federal University of Rio Grande do Norte, Brazil (CEP-UFRN), with favorable report no. 81/07. For data collection, the following multimethods were employed: a word free association test; a projective test for registering mental images; and a semistructured interview schedule. The speech contents were analyzed in accordance with the Theory of Social Representations and complemented by the Central Nucleus Theory. The discussion of the results was grounded on literary findings of the companion s participation in pregnancy as well as in risk pregnancy associated with hypertensive syndromes. The data showed fear as representation s central nucleus, while recollections of that feeling referred to death of both companion and child in addition to fear of the unknown. The categories preoccupation and carefulness, other feelings, and clinical picture of the disease represented components of the peripheral nucleus. The results concerning mental images followed the same category criteria of the word free association test fear, other feelings, preoccupation, carefulness, and clinical picture of the disease. After being processed in accordance with the principles of content analysis, the statements originated three thematic unities: fear and insecurity in the presence of the companion s risk pregnancy; attitudes of carefulness to the risk pregnancy of the partner; and humanized assistance during the companion s risk pregnancy. Considering the results, the conclusion is that the partner s risk pregnancy caused by hypertensive syndromes represents, for the man, feelings of fear, preoccupation, insecurity, lack of acceptance and information, as well as attitudes of carefulness. The results reveal necessity of reorganizing the obstetric assistance with an eye to including the man as participant in the reproductive process. That demands extension of humanized carefulness to the companion with a view to make him an active coadjutor in the assistance of high-risk pregnant

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Chronic lymphocytic leukemia (B-CLL) is a clonal proliferation of mature B lymphocytes characterized by indolent clinical course. Biologically this clonallity is characterized by low expression of surface immunoglobulin (sIg) with restriction to a single immunoglobulin light chain associated with high expression of CD5 antigen and positivity to B cell antigens lymphocytes such as CD19, CD20 and CD23 and negativity to FMC7. The immunological profile and morphological analysis of lymphoid cells are the main means for the differential diagnosis of B-CLL from other chronic lymphoproliferative diseases. The aim of this study was to evaluate the expression pattern of a variety of membrane antigens in leukemic cells originating from patients with B-CLL. In this study, peripheral blood samples from 80 patients with B-CLL were analyzed by multiparametric flow cytometry in addition to routine hematologic exams, using a panel of monoclonal antibodies (MoAb): CD45/CD14, CD3/CD19/CD45, CD4/CD8 / CD3, CD20/CD5/CD3, CD3/CD16-56/CD45, CD2/CD7, FMC7/CD23, CD103/CD22/CD20, HLADR/CD38, CD10/CD19, CD1a, CD11b and also IgM/gD, kappa and lambda immunoglobulin light chains for the detection of surface immunoglobulin and clonal restriction for immunoglobulin light chain. The Hematological data were obtained from the hematological analyzer and cytomorphological analysis in blood film stained by Leishmann. The study samples consisted of 45 men and 35 women, ages ranging from 55 to 84 years (mean 65 years). Complete white blood count showed count ranging from 10.0 to 42.0 x 109/l. (mean 50.0 x 109/l) and lymphocytes count greater than 5.0 x 109/l in all cases. The neoplastic cells displayed B-CLL phenotype (CD5+/CD19+/CD20+/HLADR+/CD23+) in the vast majority of the cases, associated to failed to stain for T cell markers (CD1a, CD2, CD4, CD3, CD7, CD8), CD103, CD14 and FMC7. Leukemic cells of most patients also expressed low intensity of IgM and IgD with restricted kappa light chain, in most cases (59,7%). This observation highlights the importance of immunophenotyping for correct diagnosis of chronic lymphoproliferative syndromes and the panel of MoAb used was sufficient for diagnostic confirmation of B-CLL

Relevância:

10.00% 10.00%

Publicador:

Resumo:

To think about a school that is for everyone has been a challenge for many people connected to education worldwide demanding from researchers of each level of knowledge an association to such effort. The study presented on this paper unites itself to the voices, movements and researches of these scholars, seeking to contribute on building possibilities on which mathematics can be thought and worked on schools in order for every student to learn, whether they have some sort of deficiency, disorders, syndromes or not. This essay has the goal to investigate the possibilities of inclusive pedagogical practices mediated by math games with rules, developed and used throughout the Universal Design perspective; a qualitative research took place with a collaborative methodology that involved managers, teachers and students from a public school situated on the city of Natal/Brazil. On the investigation math games with rules were developed and made according to the Universal Design concept, starting from initial studies which articulated theoretical groundings to the reality of school and the teacher s conceptions. After that, classes using these tools were planned collectively which oriented inclusive pedagogical practices of classes from the 1st to the 4th year of elementary school. Throughout the process many instruments such as: tape recording, video footages, notes from the researcher; the teachers and the students were used for constant work evaluation and also to record the research data. In the end, the data indicated effective contributions of the mediated pedagogical practices by games with rules under the perspective of Universal Design for Inclusive Mathematics Education

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Millon describes the normal personality by means of adaptation styles that are effective in normal environments and personality disorders such as unadapted operating styles. To operacionalize his theoretical model, Millon has built several instruments, including the Millon Clinical Multiaxial Inventory III (MCMI-III), wich consists of a self report inventory composed by 175 true or false response items, containing four verification scales, and others scales wich evaluates 14 personality patterns and 10 clinical syndromes. The Substance Dependence scale (T) is placed along with Clinical Syndromes scales. This research is justified by the lack of a Brazilian instrument to assess personality psychopathological aspects, and aims to translate and semantically adapt the MCMI-III to the Brazilian context, checking validity elements of the Substance Dependence scale, and developing a computer application for assisting the evaluation of assessment results. To this intent, 2.588 individuals data was collected, male and female, aged between 18 and 85 years, characterized as belonging to a clinical or non-clinical group, who took part in the survey via the internet or in person. Respondents completed the MCMI-III, a socio-demographic questionnaire and a subgroup also answered to the Goldberg General Health Questionnaire (GHQ). Besides descriptive statistics, we performed the analysis using the Student t test, principal components analysis and internal consistency. Despite difficulties related to translating very specific English terms, the assessment by judges, experts on Millon´s theory, and the back translation, attested the adequacy of the Brazilian version. Factorial analysis indicated the grouping of translated T scale items into three factors (social activities prejudice, lack of impulse control, and oppositional behavior), by presenting a single item on a fourth factor (apparently related to seeking pleasurable stimuli). The Cronbach alpha for this set of items was 0,82, indicating an acceptable scale reliability. The data analysis resulted in distinction of scores between clinical and non-clinical groups and between men and women; the relationship between high scores on the scale T and the other scales; scores of drug users according to the declared used substance; and the relationship between high scores on T and the verification of disorder or risk on GHQ mental health factor, indicating the instrument´s adequate sensistivity in identifying psychopathologies and the relationship between the different disorders or psychopathological personality patterns. Although further studies are necessary to develop the scores transformation factors, the computerized correction tool was adequate.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This study has as main objectives to translate and to adapt the MCMI-III to brazilian Portuguese, as well as investigate and analyze the involved modifications in the Alcohol Dependence Scale concerning to the results obtained on the validity and on the process of adaptation to Brazil. The inventory was translated and, posteriorly, applied on people with different reading levels to certify that the items are understandable to public in general, from diverse places of the country, divided into clinical and non-clinical groups. Were evaluated 2855 subjects between the ages of 18 and 85 years old, male and female, resident and dwellers of Brazilian cities. The application methods were face-to-face and computerized. Results showed that the clinical group presented significant differences between the means in comparison to the non-clinical group. Through the application of the General Health Questionnaire were developed studies related to the achievement of convergent validity and its results pointed to the relation between the instrument scores and the MCMI-III. The Alcohol Dependence Scale analysis indicated that people who reported abusive use of alcohol had highest scores, indicating adequacy of the instrument on identifying manifestation of disorders and syndromes. Nevertheless, further studies are necessary to the establishment of normative patterns to the Brazilian sample

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Urinary incontinence (UI) is a geriatric syndrome that is especially prevalent in institutionalized individuals, and that causes economic and social impacts derived from treatment costs and overload of caregiver. UI also entails physical consequences to the health of the elderly, such as urinary tract infections or pressure ulcers, among other health problems. However, the existing national research on this condition is still scarce and comprises serious methodological biases. Therefore, the objective of this study is to determine the prevalence of urinary incontinence and associated factors in institutionalized elderly. A cross-sectional study is presented herein, conducted between October and December, 2013 and carried out in 10 nursing homes in the city of Natal (Northeast Brazil). UI was verified through the program Minimum Data Set version 3.0, which was also used to assess fecal incontinence, urinary devices and UI control programs. Data collection included sociodemographic information, UI characterization, as well as variables related to the institution itself and to health conditions (comorbidities, medication, pelvic floor surgery, Barthel Index for functional capacity and Pfeiffer test for cognitive status). Bivariate analysis was performed using the Chi-Square Test (or Fisher‟s Exact Test) and the Linear Chi-Square Test, calculating the prevalence ratio with 95% confidence interval. Variables with p value under 0.20 were included in the multivariate analysis, which was performed using the Stepwise Forward logistic regression. The inclusion of variables in the final model depended on the likelihood ratio test, absence of multicollinearity and on the Hosmer-Lemeshow test. A statistical significance level of 0.05 was considered. Six (1.8%) hospitalized elderly, one individual in palliative care (0.3%) and one (0.3%) individual under the age of 60 were excluded from the study. The final sample consisted of 321 elderly, mostly females, with a mean age of 81.5 years. The prevalence of UI was 59.43% and the final model revealed statistically a significant association between UI and white race, physical inactivity, stroke, mobility constraints and cognitive decline. The most frequent UI type was functional UI due to physical or cognitive disability, and incontinence control measures were applied only to a minority of residents (approximately 8%). It is concluded that UI is a health issue that affects more than half of the institutionalized elderly, and is associated with white race, physical inactivity, stroke and other geriatric syndromes such as immobility and cognitive disability. Most of these associated factors are modifiable and therefore the findings of this study highlight the importance of UI prevention and treatment in nursing homes, which include general measures, such as physical and psychosocial activities, and specific measures, such as prompted voiding

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The use of behavioural indicators of suffering and welfare in captive animals has produced ambiguous results. In comparisons between groups, those in worse condition tend to exhibit increased overall rate of Behaviours Potentially Indicative of Stress (BPIS), but when comparing within groups, individuals differ in their stress coping strategies. This dissertation presents analyses to unravel the Behavioural Profile of a sample of 26 captive capuchin monkeys, of three different species (Sapajus libidinosus, S. flavius and S. xanthosternos), kept in different enclosure types. In total, 147,17 hours of data were collected. We explored four type of analysis: Activity Budgets, Diversity indexes, Markov chains and Sequence analyses, and Social Network Analyses, resulting in nine indexes of behavioural occurrence and organization. In chapter One we explore group differences. Results support predictions of minor sex and species differences and major differences in behavioural profile due to enclosure type: i. individuals in less enriched enclosures exhibited a more diverse BPIS repertoire and a decreased probability of a sequence with six Genus Normative Behaviour; ii. number of most probable behavioural transitions including at least one BPIS was higher in less enriched enclosures; iii. proeminence indexes indicate that BPIS function as dead ends of behavioural sequences, and proeminence of three BPIS (pacing, self-direct, active I) were higher in less enriched enclosures. Overall, these data are not supportive of BPIS as a repetitive pattern, with a mantra-like calming effect. Rather, the picture that emerges is more supportive of BPIS as activities that disrupt organization of behaviours, introducing “noise” that compromises optimal activity budget. In chapter Two we explored individual differences in stress coping strategies. We classified individuals along six axes of exploratory behaviour. These were only weakly correlated indicating low correlation among behavioural indicators of syndromes. Nevertheless, the results are suggestive of two broad stress coping strategies, similar to the bold/proactive and shy/reactive pattern: more exploratory capuchin monkeys exhibited increased values of proeminence in Pacing, aberrant sexual display and Active 1 BPIS, while less active animals exhibited increased probability in significant sequences involving at least one BPIS, and increased prominence in own stereotypy. Capuchin monkeys are known for their cognitive capacities and behavioural flexibility, therefore, the search for a consistent set of behavioural indictors of welfare and individual differences requires further studies and larger data sets. With this work we aim contributing to design scientifically grounded and statistically correct protocols for collection of behavioural data that permits comparability of results and meta-analyses, from whatever theoretical perspective interpretation it may receive.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Systemic Lupus Erythematosus (SLE) is a chronic autoimmune disease, rare, multisystem, with a very heterogeneous clinical and serological manifestations standard. The patient, in addition to suffering injuries on his physical and physiological functioning, may also face a number of psychosocial problems. Research indicates that SLE can cause significant damage to the psychological realm, especially with the presence of anxiety and depression. In 1999, the American College of Rheumatology (ACR), proposed the establishment of 19 neuropsychiatric clinical syndromes attributed to SLE. Depression lies between mood disorders and is one of the most common psychiatric manifestations in this group, being found more frequently in these patients than in the general population. Studies also suggest that social support plays an important role in the development of coping strategies, in SLE management and depression. This study has as main objective verify the association between depressive symptoms and perceived social support in patients with SLE. The specific objectives turned to: investigte the prevalence of depressive symptoms; investigate the perceived social support and verify if there is an association between depression, social support and sociodemographic variables. We used a sociodemographic questionnaire, the Beck Depression Scale, and the Perceived Social Support Scale. The analysis was performed through descriptive and inferential statistics. The final sample could count with 79 SLE women, with an average age of 35.7 years. 44 (55.7%) of the participants were married. Only 6 (7.59%) had completed higher education and 32 (40.51%) have not finished high school. Seventy-one (89.87%) had an income below three minimum salaries and 71 (89.87) practiced a religion, and the Catholic (67.71%) was the most mentioned by them. Of the total sample, 37 (46.74%) had been diagnosed SLE more than 7 years before, and 25 (31.65%) had the disease for more than 10 years. Only 19 (24.05%) had some work activity. Forty-two of them (53.17%) had depressive symptoms levels from mild to severe, and 51 (64.46%) reported pain levels of 5, or above. The study found a significant association between depressive symptoms and pain (p = 0.013) and depressive symptoms and work activity (p = 0.02). When we examined the perception of social support, the results showed high levels among participants. Using the Spearman correlation test we found a strong correlation between depressive symptoms and social support (p= 0,000037). It means that the higher the frequency of support, the lower the score of depression. These findings are relevant because depressive symptoms in patients with SLE have a multicausal and multifactorial character and may remain unnoticed, since many of them are confused with the manifestations of the disease. This fact requires a careful assessment from professionals, not only in the clinical setting, but also considering other psychosocial reasons, that may be influencing the emergence or worsening of symptoms. These results also corroborate other studies, which not only confirm the predictive role of social support in the physical wellbeing, but also in the psychological.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Systemic Lupus Erythematosus (SLE) is a chronic autoimmune disease, rare, multisystem, with a very heterogeneous clinical and serological manifestations standard. The patient, in addition to suffering injuries on his physical and physiological functioning, may also face a number of psychosocial problems. Research indicates that SLE can cause significant damage to the psychological realm, especially with the presence of anxiety and depression. In 1999, the American College of Rheumatology (ACR), proposed the establishment of 19 neuropsychiatric clinical syndromes attributed to SLE. Depression lies between mood disorders and is one of the most common psychiatric manifestations in this group, being found more frequently in these patients than in the general population. Studies also suggest that social support plays an important role in the development of coping strategies, in SLE management and depression. This study has as main objective verify the association between depressive symptoms and perceived social support in patients with SLE. The specific objectives turned to: investigte the prevalence of depressive symptoms; investigate the perceived social support and verify if there is an association between depression, social support and sociodemographic variables. We used a sociodemographic questionnaire, the Beck Depression Scale, and the Perceived Social Support Scale. The analysis was performed through descriptive and inferential statistics. The final sample could count with 79 SLE women, with an average age of 35.7 years. 44 (55.7%) of the participants were married. Only 6 (7.59%) had completed higher education and 32 (40.51%) have not finished high school. Seventy-one (89.87%) had an income below three minimum salaries and 71 (89.87) practiced a religion, and the Catholic (67.71%) was the most mentioned by them. Of the total sample, 37 (46.74%) had been diagnosed SLE more than 7 years before, and 25 (31.65%) had the disease for more than 10 years. Only 19 (24.05%) had some work activity. Forty-two of them (53.17%) had depressive symptoms levels from mild to severe, and 51 (64.46%) reported pain levels of 5, or above. The study found a significant association between depressive symptoms and pain (p = 0.013) and depressive symptoms and work activity (p = 0.02). When we examined the perception of social support, the results showed high levels among participants. Using the Spearman correlation test we found a strong correlation between depressive symptoms and social support (p= 0,000037). It means that the higher the frequency of support, the lower the score of depression. These findings are relevant because depressive symptoms in patients with SLE have a multicausal and multifactorial character and may remain unnoticed, since many of them are confused with the manifestations of the disease. This fact requires a careful assessment from professionals, not only in the clinical setting, but also considering other psychosocial reasons, that may be influencing the emergence or worsening of symptoms. These results also corroborate other studies, which not only confirm the predictive role of social support in the physical wellbeing, but also in the psychological.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

ARAUJO, Afranio Cesar de et al. Síndromes de polinização ocorrentes em uma área de Mata Atlântica, Paraíba, Brasil. Biotemas, Florianopolis, v. 4, n. 22, p.83-94, dez. 2009. Disponível em: . Acesso em: 04 out. 2010.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

studies using UV as a source of DNA damage. However, even though unrepaired UV-induced DNA damages are related to mutagenesis, cell death and tumorigenesis, they do not explain phenotypes such as neurodegeneration and internal tumors observed in patients with syndromes like Xeroderma Pigmentosum (XP) and Cockayne Syndrome (CS) that are associated with NER deficiency. Recent evidences point to a role of NER in the repair of 8-oxodG, a typical substrate of Base Excision Repair (BER). Since deficiencies in BER result in genomic instability, neurodegenerative diseases and cancer, it was investigated in this research the impact of XPC deficiency on BER functions in human cells. It was analyzed both the expression and the cellular localization of APE1, OGG1 e PARP-1, the mainly BER enzymes, in different NER-deficient human fibroblasts. The endogenous levels of these enzymes are reduced in XPC deficient cells. Surprisingly, XP-C fibroblasts were more resistant to oxidative agents than the other NER deficient fibroblasts, despite presenting the highest of 8-oxodG. Furthermore, subtle changes in the nuclear and mitochondrial localization of APE1 were detected in XP-C fibroblasts. To confirm the impact of XPC deficiency in the regulation of APE1 and OGG1 expression and activity, we constructed a XPC-complemented cell line. Although the XPC complementation was only partial, we found that XPC-complemented cells presented increased levels of OGG1 than XPC-deficient cells. The extracts from XPC-complemented cells also presented an elevated OGG1 enzimatic activity. However, it was not observed changes in APE1 expression and activity in the XPCcomplemented cells. In addition, we found that full-length APE1 (37 kDa) and OGG1- α are in the mitochondria of XPC-deficient fibroblasts and XPC-complemented fibroblasts before and after induction of oxidative stress. On the other hand, the expression of APE1 and PARP-1 are not altered in brain and liver of XPC knockout mice. However, XPC deficiency changed the APE1 localization in hypoccampus and hypothalamus. We also observed a physical interaction between XPC and APE1 proteins in human cells. In conclusion, the data suggest that XPC protein has a role in the regulation of OGG1 expression and activity in human cells and is involved mainly in the regulation of APE1 localization in mice. Aditionally, the response of NER deficient cells under oxidative stress may not be only associated to the NER deficiency per se, but it may include the new functions of NER enzymes in regulation of expression and cell localization of BER proteins