Cranes are large elegant birds that occur on all continents of the world except for South America and Antarctica. Of the fifteen species of crane worldwide, three predominantly occur in southern Africa; the Wattled crane (Bugeranus carunculatus), the Blue crane (Anthropoides paradisea) and the Crowned crane (Balearica regulorum). Crane numbers throughout the world are diminishing, mostly because of the destruction of their habitat and illegal bird trading. Efforts are underway to prevent species extinction, legally and through the compilation of a studbook that contains descriptions of physical attributes, ownership, location and possible kinships of birds in captivity . This investigation, first of its kind, WdS undertaken to assess whether twelve published and unpublished microsatellite primers developed for the related Whooping crane and Red-Crowned crane could be used to fingerprint the southern African crane species using cost effective polyacrylamide gel electrophoresis. The results obtained were then used to determine the extent of genetic variation within species and distance between species. All primer sets amplified heterologous microsatellite loci in the three crane species, however, the unpublished primers produced poorly defined fingerprints even after extensive optimization. Of the twelve microsatellite loci investigated, the Blue crane and the Wattled crane revealed a high level of polymorphism. The Blue crane displayed 76% polymorphism and the Wattled crane 92%. In contrast, for the Crowned crane, that belongs to a different subfamily, Balearicinae, only 50% of the loci were polymorphic. The alleles displayed sizes similar to that of the species for which the primers were developed. Little variation in size, less than 10 bp, was noted for the different alleles of the polymorphic loci. The number of alleles, on the other hand, at each of the polymorphic loci was found to be low. The frequency of the most prevalent allele at most of the loci was generally reasonably high. These results therefore suggest that these primer sets are not suitable for individual identification and differentiation using polyacrylamide gel electrophoresis. Xll The observed heterozygosity of the three crane species was low; 12% in Blue crane; 7% in Crowned crane; and 13% in Wattled crane. Nei's identity further confirmed the high similarity between individuals; 66-100% for Blue crane; 55-100% for Crowned crane and 41-95% for Wattled crane. This low genetic variation is attributed to possible relatedness between birds supplied by aviculturists whom have a limited number of birds in captivity. A Hardy-Weinberg test for equilibrium revealed that most of the microsatellite loci displayed a deficiency of heterozygotes, while a few loci displayed an excess of heterozygotes. In general, the Hardy Weinberg test of equilibrium supported the notion that the individuals within each of the species might have been related. Differentiation between the three crane species ranged from 3-5%, with Blue and Wattled crane displaying a higher degree of genetic similarity when compared to the Crowned crane, known to be the oldest extant crane species. The limited allelic variation within the microsatellite loci tested, as well as the extensive genetic similarity between individuals suggests that a wide-ranging search for additional microsatellite loci that are more polymorphic and contain a larger number of alleles should be undertaken for the southern African crane species. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.

Leptin, a 16 (kilo Dalton) kDa hormone secreted predominantly by white adipocytes, regulates reproduction, energy intake and expenditure, and is involved in immune system function. Previous studies have identified associations between polymorphism E2FB in the leptin gene (lep) of cattle and milk quality and quantity, feed intake, and fat deposition in dairy and beef cattle though further studies have shown inconclusive results. Furthermore, indigenous South African cattle have not been involved in lep investigations or the applicability of the marker in South African beef grading systems. An investigation was conducted into the association of an SNP of a cytosine (C) to thymine (T) SNP (single nucleotide polymorphism) mutation in exon 2 of the bovine lep (leptin) gene with weight gain, body condition, carcass fat content and quality in a population of indigenous Nguni cattle (n = 70) as well as a population of exotic British Hereford cattle (n = 54). The Hereford population had higher T-allele frequencies and a lower P-value (P = 0.172) for the E2FB genotypes than the Nguni population (P = 0.958). The resulting E2FB lep genotypes CC, CT and TT did not show an association with the pre- and post-slaughter traits initial live weight (ILW), body condition score (BCS), slaughter live weight (SLW), carcass fat content (FAT), carcass conformation (CFN) or warm carcass mass (WCM) for either population though t-tests revealed an association with the CT genotype with increased ILW than TT and a significantly higher WG in the TT genotypes than the CT (P<0.05). Subsequently, differences in pre- and post-slaughter traits in both populations were largely attributable to breed differences. The Hereford population exhibited significantly higher WG, CFN, SLW, WCM and CCM (P<0.05) than the Nguni population. The Nguni displayed significantly higher ILW and BCS values when graded in terms of the commercial South African AAA feedlot system. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

[Truncated abstract] The low density lipoprotein receptor-related protein (LRP), a member of the low-density lipoprotein (LDL) receptor gene family is involved in numerous biological processes including lipoprotein metabolism. This thesis concerns investigations into some aspects of LRP metabolism/regulation and possible roles in coronary artery disease (CAD). Specific aims were: to investigate the association between polymorphisms in the LRP gene and in its associated protein, the lipoprotein receptor-associated protein (RAP), with the risk of CAD; to extensively examine the influence of the LRP exon 22 C200T polymorphism on lipid metabolism; to develop and characterise assays for the mRNA expression of LRP and 2 other genes relevant to lipid metabolism, the LDL receptor (LDLR), and HMG CoA reductase (HMGCR); and finally, to apply the latter techniques to studies on the influence of genetic variation in LRP, and dietary and drug interventions, on LRP, LDLR and HMGCR mRNA expression in nucleated blood cells from healthy human subjects. Six hundred CAD subjects and 700 similarly aged controls were genotyped for 8 LRP gene polymorphisms as well as for the RAP V311M polymorphism. ... In the final phase of my studies, I examined the influence of 4 weeks therapy with a cholesterol lowering drug, an HMGCR inhibitor, atorvastatin (20mg daily), on the mRNA expression of LDLR, LRP and HMGCR in human nucleated blood cells. Twelve normal Caucasian male subjects aged 49 ? 5 (SD) years were studied. Plasma total cholesterol and LDL-C decreased by averages of 29 % and 41 % after the 4 week period. This was accompanied by an elevation in LDLR mRNA expression by approximately 30 35 %. In contrast, there was no significant effect on LRP and HMGCR mRNA expression. In conclusion, the original findings in this thesis included: demonstration of a strong influence of the LRP exon 22 C200T polymorphism on coronary artery disease and LDLR expression, but without a clear effect on fasting or postprandial lipid levels; data on the biological variation in LDLR and LRP gene expression in nucleated blood cells from normal subjects; the influence of an oral fat load on the expression viii of these genes, finding that LDLR was significantly depressed; and finally, the observation that statin therapy upregulated LDLR in nucleated blood cells.

Thesis (MSc (Genetics))—University of Stellenbosch, 2007. / No obvious explanations exist for the development of abnormal involuntary movements (AIM), but several hypotheses have been proposed for tardive dyskinesia (TD) development. Since TD seems to have a genetic basis, several genetic variants have been investigated in TD development in various populations. Few studies have focused on African populations. This study focused on genetic variants (previously investigated in other populations) and the development and severity of AIM and TD in a Xhosa schizophrenia population. Genotype and allele frequencies determined were compared to those described in the literature for other populations. Following a report of an association between Ala-9Val and schizophrenia in a Turkish population, this study subsequently investigated this association in the Xhosa population. MnSOD Ala-9Val was genotyped using HEX-SSCP analysis and the DRD3 Ser9Gly variant was genotyped using restriction enzyme digestion by MscI. Genotyping was followed by statistical comparisons of the various groups, as well as association analyses between the variant and schizophrenia (only for MnSOD), AIM, or TD development and severity. The groups included a Xhosa schizophrenia group, a subgroup of the Xhosa schizophrenia group that had AIM (AIM+) and did not have AIM (AIM-), a subgroup of the AIM+ group that had TD (TD+), and a healthy Xhosa control group. A possible interaction between Ala-9Val and Ser9Gly in the development of AIM and TD was also investigated. Lastly, it was attempted to genotype CYP2D6*4, CYP2D6*10 and CYP2D6*17 using various PCR methods followed by restriction enzyme analysis. MnSOD Ala-9Val genotype and allele frequencies were similar to those of the Turkish population, but differed to those of the Asian populations. No association between Ala-9Val and the development and severity of schizophrenia was found. However, a relationship between genotype and AIM or TD development was observed, as well as an association between TD severity and Ala- 9Val genotype. DRD3 Ser9Gly genotype and allele frequencies were similar to those of the African American population, but differed from other populations. No significant association between Ser9Gly and the development and severity of AIM or TD was detected, nor was an interactive effect between Ala-9Val and Ser9Gly in AIM or TD development observed. The genotyping of CYP2D6 proved difficult and these variants could therefore not be analysed. The CYP2D6*4 genotype and allele frequencies that could be determined from some samples, were similar to the frequencies described previously for African populations. While we did not find an association between Ser9Gly in TD or AIM development and severity, nor an interaction between Ala-9Val and Ser9Gly, we did observe a relationship between Ala-9Val and AIM or TD development and TD severity. The effect of this variant is probably small and other variants, specifically those in genes involved in free radical removal should be investigated in combination with Ala-9Val. With regard to CYP2D6 it is suggested that high-throughput genotyping methods (e.g. microarray technology) should be used in the future. This will enable simultaneous genotyping of several variants and can be used in various populations. This study is the first of its kind by focusing on the unique South African Xhosa population and TD or AIM development.

The presented dissertation consists of both a quantitative part and a qualitative part. The quantitative part deals with the relationship between 5-HTTLPR S/L, MAOA H/L, and COMT Val158Met polymorphisms, the stress reaction of new-born infants after a heel stick blood draw (measured by determining salivary cortisol at three time points) and temperament assessed at age three months by Rothbarth's Infant Behavior Questionnaire-Revised in a sample of 84 infants. Observed polymorphisms were related both to the course of the stress reaction and to temperament. The short allele of serotonin transporter polymorphism was connected to higher scores in the secondary scale of Negative Affect and lower scores in the secondary scale of Attention/Regulation. Homozygotes for the more active allele of MAOA polymorphism (HH) had the lowest scores in Negative Affect compared to both of the remaining groups, they also had higher scores in the secondary scale of Extraversion and Attention/Regulation and a greater decrease of cortisol in comparison to HL heterozygotes. The presence of low-active L allele predisposed their carriers to higher scores in Negative Affect and lower scores in Attention/Regulation. LL homozygotes had the highest increase of cortisol after a heel stick blood draw. The Met allele of COMT Val158Met polymorphism was connected to higher Extraversion and Attention/Regulation and a greater cortisol decrease. It was possible to predict all three secondary scales of IBQ-R from the stress reaction after the heel stick blood draw. Negative Affect was predicted by a higher increase and a lower decrease of cortisol. Extraversion and Attention/Regulation were predicted by a greater cortisol decrease. The magnitude of cortisol decrease partially mediated the influence of COMT Val158Met polymorphism on Extraversion. The qualitative part of the dissertation is a multi-casuistic study of six couples parenting infants with difficult temperaments. It is based on semi-structured interviews that were analysed in accordance with qualitative procedures. The most difficult infant displays to manage were unsoothable crying in the first six months and early sleeplessness and a later escalation of sleeping problems. Mothers were esentially not able to gain control over the amount of crying, but some of them managed to influence their experience to achieve a greater acceptance of it. To do this, it was necessary for them to eliminate their feelings of failure in the parental role. The parents' biggest dilemma concerning their infants' sleeping problems was whether to use the "cry it out" strategy or not to manage them. For some parents parenting a difficult infant was an opportunity to re-evaluate their approach to parenting and the parental role, significantly broadening the concept of both. Caring for a difficult infant significantly strained the marital relationship; four couples experienced marital crisis during the care of their child. The father's involvement in infant care seemed very important in this respect. Insufficient involvement led to dissatisfaction in the mother, the way the mother communicated her demands further influenced the marital relationship. Particular behaviour that the mother understood as the father's involvement in infant care emerged.

Made available in DSpace on 2016-12-23T13:56:07Z (GMT). No. of bitstreams: 1 Dissertacao de Adriana Tonani de Mattos.pdf: 2693529 bytes, checksum: 00310e354cac5ba29311696cfd985068 (MD5) Previous issue date: 2010-12-15 / Human papillomaviruses (HPV) are epitheliotropic viruses that infect skin tissue or mucous membranes, closely related to development of lesions in the genital tract, ranging from warts to invasive cervical cancer. These injuries are caused by different types of HPV that are classified into low and high risk types according to the association with cervical cancer. HIV seropositive women are mostly affected by HPV and are more prone to develop cervical cancer. The aim of this study was to evaluate the frequency of HPV types in seropositive and seronegative women for HIV. Therefore, cervical samples, part of the human bank samples of the Virology Laboratory, were analised from women known to be positive for HPV (n=87) attending the Reference Center STD / Aids Clinic in Vitória-ES, during March to December 2006. DNA was extracted by commercial kit QIAamp... / Os papilomavírus humanos (HPV) são vírus epiteliotrópicos que infectam tecido cutâneo ou mucoso e estão relacionados com desenvolvimento de lesões que, no trato genital, variam de verrugas ao câncer cervical invasivo. Estas lesões são causadas por diferentes tipos de HPV, que são classificados em baixo e alto risco conforme sua associação com câncer cervical. Sabe-se que mulheres soropositivas para HIV são mais acometidas por infecções por HPV e estão mais propensas ao desenvolvimento de câncer cervical. O objetivo desse estudo foi avaliar a frequência de tipos de HPV em mulheres soropositivas e soronegativas para HIV. Para isso foram analisadas amostras de escovado cervical, que faziam parte do banco de amostras do Laboratório de Virologia, de mulheres conhecidamente positivas para HPV (n=87) atendidas no Centro de Referência DST/AIDS, em Vitória-ES, no período de março a dezembro de 2006. O DNA das amostras foi extraído utilizando kit comercial QIAamp® DNA Mini Kit ou através do método de isotiocinanato de guanidina e sílica. DNA do HPV foi amplificado por PCR utilizando os iniciadores degenerados MY09/MY11 ou PGMY09/PGM11 biotinilados e a genotipagem foi realizada por Restriction Fragment Length Polymorphism (RFLP) ou por Reverse Line Blot (RLB), respectivamente. Do total de amostras, 97,7% foram genotipadas e 31 tipos distintos detectados: 6, 11, 13, 16, 18, 26, 31, 31b, 32, 33, 34, 35, 42, 44, 51, 52, 53, 55, 56, 58, 59, 61, 62, 64, 66, 68, 71, 81, 82, 83 e 84. O tipo mais prevalente foi o HPV16, tanto nas mulheres soropositivas quanto nas soronegativas para HIV, seguido pelos tipos 6, 53 e 11. O tipo 13, incomum em amostras cervicais, foi observado nesse estudo, porém a quantidade de amostras não foi suficiente para a realização de seqüenciamento para a confirmação deste tipo viral. Os tipos oncogênicos foram mais comuns nas amostras de mulheres soropositivas para HIV, porém com número semelhante e o número de infecções múltiplas foi maior entre as mulheres HIV positivas. Este estudo revelou uma grande diversidade de tipos de HPV na região

L’objectif général de cette thèse était d’étudier le rôle de la protéine soluble HLA-G (sHLA- G) dans la variabilité des réponses à l’infection par P. falciparum chez la femme enceinte et son nouveau-né pendant ses deux premières années de vie. Précisément, nous avons étudié, chez les mères pendant la grossesse et leurs nourrissons de la naissance à 2 ans, les relations entre les niveaux de sHLA-G et l’infection palustre au niveau périphérique et placentaire. Nous avons également étudié les polymorphismes génétiques situés dans la région 3’UTR du gène HLA- G chez les mères et leurs nourrissons par la détermination des fréquences alléliques, génotypiques et haplotypiques afin évaluer l’impact de ces polymorphismes sur la cinétique d’expression de sHLA-G dans un contexte d’infection palustre. Nos résultats ont montré une association entre le niveau élevé de sHLA-G chez les nourrissons et l’augmentation du risque d’infection palustre au cours du trimestre suivant. Ces niveaux élevés de sHLA-G dans le sang de cordon ont été également associés au faible poids de naissance du nouveau-né. De même, nous avons trouvé une forte corrélation entre les niveaux de sHLA-G maternels dans le sang périphérique à l’accouchement et ceux de l’enfant dans le sang du cordon à la naissance. Nous avons aussi montré l’existence de trois profils d’expression de sHLA-G chez les individus inclus dans l'étude. Certains individus expriment la protéine à chaque prélèvement (HLA-G ++) alors que d’autres l’expriment par intermittence (HLA-G +-) ou ne l’expriment pas (HLA-G --). Le risque de développer un accès palustre chez les mères était respectivement trois fois plus élevé (p=0,001, OR=3,47;p=0,008, OR=3,14) chez celles appartenant au groupe HLA-G (++) et HLA-G (+-) que le groupe HLA-G (--). L’analyse génétique de la région 3’UTR du gène nous a permis de mettre en évidence huit sites polymorphes dans cette région et de construire six haplotypes correspondant (UTR 1, 2, 3, 4, 5, 6). Nous avons aussi montré chez les mères une association entre l’allèle T en position +3001 (C/T) et une expression plus fréquente de sHLA-G tandis que l’allèle C en position +3003 (T/C) et l’haplotype UTR-4 ont été associés à une expression moins fréquente de la protéine. Ces associations n’ont pas été mises en évidence chez les enfants. L’ensemble de ces résultats suggère l'implication de sHLA-G dans la sensibilité à l'infection palustre. Cette sensibilité serait, en partie, corrélée à l’inhibition des réponses anticorps spécifiquement dirigées contre P. falciparum. sHLA-G pourrait donc à terme devenir un bio-marqueur de susceptibilité au paludisme chez la femme enceinte et chez le nouveau-né au cours des premières années de vie. / The general objective of this thesis was to study the role of soluble HLA-G protein (sHLA-G) in the variability of individual response to malaria during pregnancy and during the first 2 years of infant life. Actually, we assessed the relationships between sHLA-G and malaria infection in peripheral and placental blood. We also investigated the effect of polymorphisms in the 3’UTR region of HLA-G gene in 400 mothers and their infants on the kinetic of sHLA-G expression three times during pregnancy and at 6, 9, 12, 18, 24 months of life in a context of malaria infection. Our results showed that high levels of sHLA-G increased the risk of malaria at the subsequent trimester in infants and were associated with low birth weight. We also showed a strong correlation between the plasmatic sHLA-G level of the mothers at delivery and those of newborns in cord blood. We found that the risk of developing malaria in mothers was respectively three fold higher in the HLA-G (++) (OR=3.47; p=0.001) and HLA-G(+-)(OR=3.14, p=0.008) groups compared to HLA-G (--) group. Besides, we described eight polymorphic sites in the 3’UTR corresponding to six haplotypes (UTR 1, 2, 3, 4, 5, 6) and showed in mothers, an association between the allele T at position +3001 (C/T) and a higher frequency of sHLA-G expression. However, the allele C at position +3003 (T/C) and UTR-4 were associated to a lower frequency of sHLA-G expression. In infants, no association was observed between alleles or haplotypes and expression of the soluble protein. Overall, these results suggest that sHLA-G is implicated in malaria susceptibility. This could be partly, related to the inhibition of P. falciparum-specific antibody responses. Therefore, sHLA-G might be useful as a bio- marker of malaria susceptibility during pregnancy and during the first years of infancy.

Orientador: Luiz Carlos de Mattos / Banca: Antonio Carlos Pires / Banca: Haroldo Wilson Moreira / Resumo: O diabetes melito (DM) é um grupo heterogêneo de alterações metabólicas, caracterizado por hiperglicemia crônica, com alterações do metabolismo de carboidratos, ácidos graxos e proteínas. O diabetes melito tipo 2 (DMT2) é a forma mais comum dessa doença, acomentendo aproximadamente 90% dos indivíduos que apresentam DM. Caracteriza-se principalmente por modificações da ação e secreção de insulina, embora sua etiologia, genética e fisiopatologia específicas ainda não estejam completamente determinadas. Os pacientes com DMT2 apresentam maior risco de desenvolvimento de complicações macro e microvasculares. Estudos revelaram que a enzima conversora de angiotensina (ECA) e a adenosina deaminase (ADA) podem estar relacionadas ao desenvolvimento de DMT2 ou de suas complicações. Com base nesses dados, foram estudados os polimorfismos I/D do gene ECA e TaqI do gene ADA em 162 indivíduos com DMT2, e 160 indivíduos saudáveis. Segundo a Associação Americana de Diabetes, os indivíduos diabéticos que apresentam HDLc abaixo de 40mg/dl ou LDLc acima de 100 mg/dl ou triglicerídeos acima de 150 mg/dl apresentam maior risco de desenvolvimento de doenças cardiovasculares. Por isso, foram selecionados 81 indivíduos com essas características para compor o grupo de estudo de pacientes diabéticos com "risco de doença cardiovascular". Os polimorfismos foram avaliados por PCR e PCR-RFLP para os genes da ECA e ADA respectivamente. As frequências obtidas para o polimorfismo do gene ECA foram: pacientes diabéticos: I/I (19,1%); I/D (52,5%); D/D (28,4%); grupo controle I/I (12,5%); I/D (55,6%); D/D (31,9%) e grupo de diabéticos com riscos de doença cardiovascular I/I (16%); I/D (59,3%); D/D (24,7%). E para o gene ADA: em pacientes diabéticos ADA*1/*1 (89,31%); ADA*1/*2 (10,06%); ADA*2/*2 (0,63%); grupo controle ADA*1/*1 (91,25%); ADA*1/*2 (7,50%); ADA*2/*2 (1,25%); pacientes... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Diabetes mellitus (DM) is a heterogeneous group of metabolic disorders characterized by chronic hyperglycemia, with changes in the carbohydrates, fatty acids and proteins metabolism. Diabetes mellitus type 2 (DMT2) is the most common form of this disease, that affect approximately 90% of people who have DM. It is characterized mainly by changes in the action and insulin secretion, although the etiology, genetics and specific pathophysiology of the disease is not yet completely determined. DMT2 patients have a higher risk of developing macro and microvascular complications. Studies have shown that angiotensin-converting enzyme (ACE) and adenosine deaminase (ADA) may be related to the development of DMT2 or its complications. Based on these data, we studied the polymorphisms I / D of the ACE gene and the polymorphism TaqI in the ADA gene, in 162 patients with DMT2, and 160 blood donors. According to the American Diabetes Association, people with diabetes who have HDL-C below 40 mg / dL or LDL-C above 100 mg / dl or triglycerides above 150 mg / dl are at increased risk of developing cardiovascular disease. Therefore, we selected 81 individuals with these characteristics to compose the study group of diabetic patients named "risk of cardiovascular disease ". The polymorphisms are evaluated by PCR for ACE gene and PCR-RFLP for the ADA Gene. The frequencies obtained for the ACE gene polymorphism were: diabetic patients: I / I (19.1%), I / D (52.5%) and D / D (28.4%), control group: I / I ( 12.5%) I / D (55.6%) and D / D (31.9%) and group of patients with cardiovascular disease risk: I / I (16%) I / D (59.3% ), D / D (24.7%). And for the ADA gene polymorphism: in diabetic patients: ADA * 1 / * 1 (89.31%); ADA * 1 / * 2 (10.06%), ADA * 2 / * 2 (0.63%); control group: ADA * 1 / * 1 (91.25%); ADA * 1 / * 2 (7.50%); ADA * 2 / * 2 (1.25%), and patients with cardiovascular risk:... (Complete abstract click electronic access below) / Mestre

Há décadas a exposição ao mercúrio é alvo de estudos toxicológicos devido ao alto potencial de danos a saúde humana. Na região amazônica os primeiros estudos reportavam a exposição ocupacional pelo uso nos garimpos de ouro, entretanto recentemente destacam-se os estudos relacionados a exposição ambiental que ocorre na região decorrente do consumo de peixes contaminados com mercúrio. Muitos estudos se concentram em populações ribeirinhas residentes na região do rio Tapajós, onde o consumo de peixes é frequente e o metil-mercúrio (MeHg) contido nos peixes é o responsável pela exposição dessas pessoas ao metal. O MeHg apresenta efeitos tóxicos relevantes sobre o sistema cardiovascular, e muitos grupos de pesquisa buscam elucidar os mecanismos que expliquem tais efeitos. Alguns estudos apontam uma diminuição significativa na disponibilidade do óxido nítrico (NO) após exposição ao organometal, o que poderia contribuir para uma alteração da fisiologia cardiovascular uma vez que o NO é um modulados desse sistema. O NO é sintetizado pela óxido nítrico sintase endotelial (eNOS) e sua atividade pode ser alterada por vários fatores, dentre eles, os polimorfismos nos genes que codificam essa proteína, são eles: T-786C na região promotora, 27-pb VNTR no intron 4 e Glu298Asp no exon 7. Neste sentido, o presente estudo teve por objetivo avaliar os efeitos dos polimorfismos da eNOS sobre a síntese de NO entre os indivíduos expostos a metilmercúrio. Foram analisadas amostras de sangue de 214 voluntários com idade entre 15 e 84 anos, dos quais 103 homens e 111 mulheres. A concentração de mercúrio no sangue (Hg sangue) total variou de 1,7 a 179,3 µg/L e a concentração plasmática de nitrito variou entre 85,7 e 695,8 M. Foram determinados os valores de pressão arterial sistólica (PAS), pressão arterial diastólica (PAD), índice de massa corporal (IMC) e freqüência cardíaca (FC) de todos os voluntários. A PAS média foi de 119,8 mmHg e a média da PAD foi 71,8 mmHg. O IMC médio foi de 24,5 Kg/m2 e a FC média foi 70,4 batimentos por minuto (bpm). Não foram observadas diferenças entre os grupos, segundo genótipos dos três polimorfismos, quanto às características dos voluntários: idade, PAS, PAD, IMC, FC, Hg sangue e as concentrações plasmáticas de nitrito. Quando os polimorfismos foram estudados isoladamente foi observado que o alelo C na região promotora, o alelo 4b no intron 4 e o alelo Glu no exon 7 apresentaram-se associados a concentrações reduzidas e nitrito plasmático. Quando a população foi estratificada com base na concentração de Hg essa associação desapareceu, provavelmente mascarada pelas altas concentrações do metal. Entretanto quando foram estudados os haplótipos pode ser observada novamente a associação desses mesmos alelos com a diminuição da concentração do nitrito, confirmando os achados iniciais. O haplótipo mais frequente na população combina os alelos selvagens para todos os polimorfismos (T, 4b e G) e o haplótipo menos freqüente combina os alelos variantes. O haplótipo associado à menor concentração plasmática de nitrito combina os alelos selvagens (C, 4b e G), confirmando os primeiros resultados. Essa abordagem haplotípica é muito útil na observação de efeitos mais discretos uma vez que é possível observar os efeitos dos três polimorfismos agindo simultaneamente sobre uma variável, nesse caso o óxido nítrico. O presente estudo sugere que os fatores genéticos exercem grande influência sobre a produção e biodisponibilidade de NO e que esses fatores combinados com a exposição ambiental ao Hg podem agir de maneira sinérgica, aumentando a suscetibilidade aos efeitos cardiotóxicos do metal através da modulação da atividade da eNOS. / The mercury (Hg) exposure has been target of toxicological studies due the high potential of damage to human health. In the Amazon region the first studies reported the occupational exposure due the use in gold mining, however, recently become relevant the studies about the environment exposure due the fish intake in the riparian population. Several studies have been concentrated in the riparian community in the Tapajós river region, where the fish consumption is frequent and the methylmercury content in fish is responsible to exposure of this people. The MeHg presents toxic effects in the cardiovascular system and many researches groups try to elucidate the mechanisms that explain this effects. Some studies report a significant reducing in nitric oxide (NO) production after the Hg exposure, which could contribute to an altered physiology of the cardiovascular system, once the NO is a modulating factor of this system. The NO is produced by the endothelial nitric oxide synthase (eNOS) and its activity can be altered by many factors like polymorphisms in gene that codify this protein, among this: : T-786C in the promoter region, 27-pb VNTR in intron 4 and Glu298Asp in exon 7. In this regard, the present study mean to evaluate the effects of the eNOS polymorphisms over the NO synthesis among the Hg exposed subjects. In this work, the whole blood samples of 214 volunteers were analyzed for determination of Hg concentration, nitrite plasma concentration and genotyping. The age of the volunteers varied between 15 and 84 years old, including 103 men and 111 women. The blood mercury concentration varied between 1.7 and 179.3 µg/L and the nitrite plasma concentration varied between 85.7 and 695.8 M. Was determinate the systolic arterial pressure (SAP), diastolic arterial pressure (DAP), body mass index (BMI) and heart rate (HR). The SAP mean was 119.8 mmHg and the DAP mean was 71.8 mmHg. The BMI mean was 24.5 Kg/m2 and the HR mean was 70.4 beats per minute. There was no difference among the groups of the three polymorphisms according the volunteers characteristics: age, DAP, SAP, BMI, HR, blood Hg concentration and nitrite plasma concentration. When the polymorphisms were observed separately the reduced nitrite plasma concentration was associated with the presence of the alleles: C in promoter region, 4b in intron 4 and G in exon 7, however there is lack of association when the volunteers were grouped according the blood Hg concentration, probably due a mask effect of the high Hg concentration. When these three polymorphisms were observed simultaneously, in analysis of the haplotypes, the association between the same alleles and the nitrite plasma concentration was observed again, confirming the initial findings. The commonest haplotype in the volunteers combine the alleles of the three polymorphisms (T, 4b and G) and the less frequent haplotype combine the three variants alleles. There was an association between the haplotype C, 4b and G and reduced nitrite plasma concentration, according the result of the polymorphisms separately. The haplotype analysis is too interesting to observe discrete effects, once is possible to analyze the effects of the three polymorphisms acting simultaneously above one variable, in this case, nitric oxide production. The present study suggest that genetic factors could exert a relevant influence above the NO production and bioavailability and that this factors combined with environmental Hg exposure can acting synergic, increasing the susceptibility to Hg cardiovascular effects, through the modulation of the eNOS activity.

MSc (Microbiology) / Department of Microbiology