IMMUNOHISTOCHEMICAL DETECTION OF L CELLS IN GASTROINTESTINAL TRACT MUCOSA OF PATIENTS AFTER SURGICAL TREATMENT FOR CONTROL OF TYPE 2 DIABETES MELLITUS.

OBJECTIVE: Type 2 diabetes mellitus (T2DM) is a disease of global impact that has led to an increase in comorbidities and mortality in several countries. Immunoexpression of the incretin hormones such as glucagon-like peptide-1 (GLP-1) and peptide YY (3-36) (PYY3-36) can be used as a scorer in the gastrointestinal tract to analyze L-cell activity in response to T2DM treatment. This study aimed to investigate the presence, location, and secretion of L cells in the small intestine of patients undergoing the form of bariatric surgery denominated adaptive gastroenteromentectomy with partial bipartition. METHODS: Immunohistochemical assays, quantitative real-time polymerase chain reaction (qPCR), and Western blot analysis were performed on samples of intestinal mucosa from patients with T2DM in both the preoperative and postoperative periods. RESULTS: All results were consistent and indicated basal expression and secretion of GLP-1 and PYY3-36 incretins by L cells. A greater density of cells was demonstrated in the most distal portions of the small intestine. No significant difference was found between GLP-1 and PYY3-36 expression levels in the preoperative and postoperative periods because of prolonged fasting during which the samples were collected. CONCLUSION: The greater number of L cells in activity implies better peptide signaling, response, and functioning of the neuroendocrine system.

Molecular data reveal a complex population genetic structure for Psalidodon scabripinnis (Teleostei: Characidae) in the Atlantic Rainforest, Brazil.

Recently renamed, Psalidodon scabripinnis populations of Serra da Mantiqueira, previously known as Astyanax scabripinnis have been deeply studied in the last years. These populations are small and isolated and occur very close to the watershed between Paraíba do Sul River basin and Upper Paraná River basin, in Serra da Mantiqueira region in the Atlantic Rainforest. These conditions arouse the interest in knowing theor genetic conservation status and how they responded to the separation between the two rivers basins. Therefore, we accessed the genetic diversity of five P. scabripinnis populations of this region with microsatellites and mitochondrial data. The results showed a complex structure pattern that doesn't match the simple basin separation and a reasonably conservation status when compared with other populations of the same family or with similar natural history.

Immunohistochemical detection of l cells in gastrointestinal tract mucosa of patients after surgical treatment for control of type 2 diabetes mellitus / Detecção imunohistoquímica de células l na mucosa do trato gastrointestinal de pacientes após tratamento cirúrgico para controle de diabetes mellitus tipo 2

ABSTRACT - BACKGROUND: Type 2 diabetes mellitus (T2DM) is a disease of global impact that has led to an increase in comorbidities and mortality in several countries. Immunoexpression of the incretin hormones such as glucagon-like peptide-1 (GLP-1) and peptide YY (3-36) (PYY3-36) can be used as a scorer in the gastrointestinal tract to analyze L-cell activity in response to T2DM treatment. OBJECTIVE: This study aimed to investigate the presence, location, and secretion of L cells in the small intestine of patients undergoing the form of bariatric surgery denominated adaptive gastroenteromentectomy with partial bipartition. METHODS: Immunohistochemical assays, quantitative real-time polymerase chain reaction (qPCR), and Western blot analysis were performed on samples of intestinal mucosa from patients with T2DM in both the preoperative and postoperative periods. RESULTS: All results were consistent and indicated basal expression and secretion of GLP-1 and PYY3-36 incretins by L cells. A greater density of cells was demonstrated in the most distal portions of the small intestine. No significant difference was found between GLP-1 and PYY3-36 expression levels in the preoperative and postoperative periods because of prolonged fasting during which the samples were collected. CONCLUSION: The greater number of L cells in activity implies better peptide signaling, response, and functioning of the neuroendocrine system.

RESUMO - RACIONAL: O diabetes tipo 2 (DM2) é uma doença de impacto mundial que tem levado ao aumento de comorbidades e mortalidade em vários países. A imunoexpressão dos hormônios incretínicos glp-1 e pyy3-36, pode ser usada como marcador no trato gastrointestinal para analisar a atividade da célula L em resposta ao tratamento do DM2. OBJETIVO: O presente estudo teve como objetivo investigar a presença, localização e secreção de células L no intestino delgado de pacientes submetidos à forma de cirurgia bariátrica denominada gastroenteromentectomia adaptativa com bipartição parcial. MÉTODOS: Ensaios imunohistoquímicos, reação quantitativa em cadeia de polimerase em tempo real (qPCR) e análise de manchas ocidentais foram realizados em amostras de mucosa intestinal de pacientes com diabetes tipo 2 nos períodos pré- e pós-operatório. RESULTADOS: Todos os resultados foram consistentes e indicaram expressão basal e secreção de peptídeos glucagon-1 (GLP-1) e peptídeos YY (PYY3-36) incretinas por células L. Uma maior densidade de células foi demonstrada nas porções mais distais do intestino delgado. Não foi encontrada diferença significativa entre os níveis de expressão GLP-1 e PYY3-36 nos períodos pré-operatório e pós-operatório, provavelmente devido ao estado de jejum prolongado durante o qual as amostras foram coletadas CONCLUSÃO: O maior número de células L em atividade implica melhor sinalização de peptídeo, resposta e funcionamento do sistema neuroendócrino.

Silencing of Transposable Elements Mediated by 5-mC and Compensation of the Heterochromatin Content by Presence of B Chromosomes in Astyanax scabripinnis.

The way in which transcriptional activity overcomes the physical DNA structure and gene regulation mechanisms involves complex processes that are not yet fully understood. Modifications in the cytosine-guanine sequence of DNA by 5-mC are preferentially located in heterochromatic regions and are related to gene silencing. Herein, we investigate evidence of epigenetic regulation related to the B chromosome model and transposable elements in A. scabripinnis. Indirect immunofluorescence using anti-5-mC to mark methylated regions was employed along with quantitative ELISA to determine the total genomic DNA methylation level. 5-mC signals were dispersed in the chromosomes of both females and males, with preferential accumulation in the B chromosome. In addition to the heterochromatic methylated regions, our results suggest that methylation is associated with transposable elements (LINE and Tc1-Mariner). Heterochromatin content was measured based on the C-band length in relation to the size of chromosome 1. The B chromosome in A. scabripinnis comprises heterochromatin located in the pericentromeric region of both arms of this isochromosome. In this context, individuals with B chromosomes should have an increased heterochromatin content when compared to individuals that do not. Although, both heterochromatin content and genome methylation showed no significant differences between sexes or in relation to the occurrence of B chromosomes. Our evidence suggests that the B chromosome can have a compensation effect on the heterochromatin content and that methylation possibly operates to silence TEs in A. scabripinnis. This represents a sui generis compensation and gene activity buffering mechanism.

Dynamics of Replication and Nuclear Localization of the B Chromosome in Kidney Tissue Cells in Astyanax scabripinnis (Teleostei: Characidae).

B chromosomes are extra genomic compounds found in different taxonomic groups, including plants and animals. Obtaining patterns of resolutive chromosomal bands is necessary to understand the nuclear organization, variability and nature of B chromosome chromatin and possible transcriptional regions. In this study, we analyzed 35 Astyanax scabripinnis specimens sampled from Fazenda Lavrinha, a stream in the Paraíba do Sul river basin, Brazil. Through the incorporation of the thymidine analog 5'-bromo-2'-deoxyuridine (5-BrdU) in vivo, it was possible to recognize the replicating regions of the B chromosome at the beginning of the S phase, differentially characterized in relationship to the regions of late replication. In this perspective, it is possible to suggest that the B chromosome of this species possesses a territory and the chromatin accessible for transcription, especially in the light (i.e., early replicating) bands (p1.1; p1.3; and p2.1 and q1.1, q1.3, q2.1, and q2.2). The late-replicating regions are corresponding to the blocks of constitutive heterochromatin. They show a preferential accumulation of satellite DNA As51. By the use of the fluorochrome chromomycin A3 (CMA3), it was possible to identify GC-rich chromosomal regions, corresponding to late-replicating parts of genome, confirming the revealed data by the replication banding and C-banding. In addition, the analysis by confocal microscopy in kidney cells indicates the location of a peripheral anchorage of this chromosome in the nuclear lamina, reinforcing the idea of downregulation of the associated regions.

Differential Expression of Genes Related to Sexual Determination Can Modify the Reproductive Cycle of Astyanax scabripinnis (Characiformes: Characidae) in B Chromosome Carrier Individuals.

The species complex Astyanax scabripinnis is one of the most studied with respect to origin, distribution, and frequency of B chromosomes, and is considered a model organism for evolutionary studies. Research using population inferences about the occurrence and frequency of the B chromosome shows seasonal variation between sexes, which is associated with the presence of this supernumerary element. We hypothesized that the B chromosome could influence the sex ratio of these animals. Based on this assumption, the present work aimed to investigate if differences exist among levels of gene expression with qRT-PCR of the amh (associated with testicular differentiation) and foxl2a (associated with ovarian differentiation) genes between B-carrier and non-B-carrier individuals. The results showed that for the amh gene, the difference in expression between animals with B chromosomes was not accentuated compared to that in animals without this chromosome. Expression of foxl2a in B-carrier females, however, was reduced by 73.56% compared to females that lacked the B chromosome. Males had no difference in expression of the amh and foxl2a genes between carriers and non-carriers of the B chromosome. Results indicate that the presence of B chromosomes is correlated with the differential expression of sex-associated genes. An analysis of these results integrated with data from other studies on the reproductive cycle in the same species reveals that this difference in expression may be expanding the reproductive cycle of the species.

Genetic variability in a population of Astyanax scabripinnis: recent bottleneck and the possible influence of individuals with B chromosomes

Access the genetic variability of endangered and isolated populations has become an important conservation tool. Astyanax scabripinnis is a well-known fish model for genetic studies, forming very isolated populations in headwaters. Besides that, this species frequently presents supernumerary chromosomes, which elevates the interest on genetic studies. Genetic diversity of an Astyanax scabripinnispopulation from the Atlantic Forest (Serra da Mantiqueira region, Brazil) was assessed with microsatellite markers for the first time. Since microsatellite markers are not described for this species, we tested markers described for a related species for transferability to A. scabripinnis. Six polymorphic loci were sufficiently reliable for population genetic analysis. We found that this population passed through a recent bottleneck because of the presence of an excess of heterozygotes, low allelic diversity, heterozygosity excess, and small effective population size. Individuals with and without B chromosomes were previously identified in this population and our study found private alleles in the individuals without B chromosomes. Furthermore, when individuals without B chromosomes were removed from the analysis, the population did not present heterozygosity excess, suggesting that the bottleneck event was driven by individuals with B chromosomes. Our results provide an insight into the value of microsatellite markers as molecular tools and is the first genetic study using molecular data of A. scabripinnis from this area.

Differential Expression of dmrt1 in Astyanax scabripinnis (Teleostei, Characidade) Is Correlated with B Chromosome Occurrence.

Astyanax is an abundant fish genus in South America. Some species of this group are characterized by the presence of B chromosomes and absence of morphologically differentiated sex chromosomes. In this study, we used quantitative real-time polymerase chain reaction to characterize mRNA expression of dmrt1 in Astyanax scabripinnis gonads. Maturing gonads of males with the B chromosome overexpressed dmrt1. Our findings suggest that B chromosomes may have an adaptive role in A. scabripinnis sex determination and maintenance.

Variability and evolutionary implications of repetitive DNA dynamics in genome of Astyanax scabripinnis (Teleostei, Characidae).

DNA sequences of multiple copies help in understanding evolutionary mechanisms, genomic structures and karyotype differentiation. The current study investigates the organization and distribution of different repetitive DNA in the standard complement and B chromosomes in Astyanax scabripinnis (Jenyns, 1842) chromosomes from three allopatric populations in Campos do Jordão region, São Paulo State, Brazil. The location of microsatellite sequences showed different chromosome distribution between Lavrinha Farm Stream (LFS) and Lake of Pedalinho (LP) populations. However, the karyotype of these populations basically followed the pattern of dispersed distribution in the A complement, conspicuous in telomeric/interstitial regions and preferential accumulation in the B chromosome. The B chromosome showed heterogeneous location of microsatellite probes CA, CAC and GA. The H3 and H4 histone genes were isolated from the total genome of the species and then the chromosomal mapping was performed by fluorescence in situ hybridization (FISH). The FISH signals showed high similarity for the probes H3 and H4 mapping in genomes of the populations analyzed. The sequences (GATA) n revealed a sex-specific trend between the chromosomal location in males and females at (LFS) and (LP) populations. Although species that comprise the Astyanax scabripinnis complex do not have morphologically differentiated sex chromosomes, the preferential GATA location - sex-associated - may represent a sex chromosome in differentiation.

Fragile sites, dysfunctional telomere and chromosome fusions: What is 5S rDNA role?

Repetitive DNA regions are known as fragile chromosomal sites which present a high flexibility and low stability. Our focus was characterize fragile sites in 5S rDNA regions. The Ancistrus sp. species shows a diploid number of 50 and an indicative Robertsonian fusion at chromosomal pair 1. Two sequences of 5S rDNA were identified: 5S.1 rDNA and 5S.2 rDNA. The first sequence gathers the necessary structures to gene expression and shows a functional secondary structure prediction. Otherwise, the 5S.2 rDNA sequence does not contain the upstream sequences that are required to expression, furthermore its structure prediction reveals a nonfunctional ribosomal RNA. The chromosomal mapping revealed several 5S.1 and 5S.2 rDNA clusters. In addition, the 5S.2 rDNA clusters were found in acrocentric and metacentric chromosomes proximal regions. The pair 1 5S.2 rDNA cluster is co-located with interstitial telomeric sites (ITS). Our results indicate that its clusters are hotspots to chromosomal breaks. During the meiotic prophase bouquet arrangement, double strand breaks (DSBs) at proximal 5S.2 rDNA of acrocentric chromosomes could lead to homologous and non-homologous repair mechanisms as Robertsonian fusions. Still, ITS sites provides chromosomal instability, resulting in telomeric recombination via TRF2 shelterin protein and a series of breakage-fusion-bridge cycles. Our proposal is that 5S rDNA derived sequences, act as chromosomal fragile sites in association with some chromosomal rearrangements of Loricariidae.

Swim training and the genetic expression of adipokines in monosodium glutamate-treated obese rats.

OBJECTIVE: The aim of this study was to evaluate the genetic expression of adipokines in the adipocytes of monosodium glutamate (MSG)-treated obese rats submitted to physical activity. MATERIALS AND METHODS: Obesity was induced by neonatal MSG administration. Exercised rats (MSG and control) were subjected to swim training for 30 min for 10 weeks, whereas their respective controls remained sedentary. Total RNA was obtained from sections of the mesenteric adipose tissue of the rats. mRNA levels of adiponectin (Adipoq), tumor necrosis factor alpha (Tnf), peroxisome proliferator-activated receptor alpha (Ppara), and peroxisome proliferator-activated receptor gamma (Pparg) adipokines were quantified by quantitative Real-Time Polymerase Chain Reaction (qRT-PCR). RESULTS: In the exercise-trained control group, the expression of Adipoq increased compared to the sedentary control, which was not observed in the MSG-obese rats. Increased levels of Tnf in MSG-obese rats were not reversed by the swim training. The expression of Ppara was higher in sedentary MSG-obese rats compared to the sedentary control. Swimming increased this adipokine expression in the exercise-trained control rats compared to the sedentary ones. mRNA levels of Pparg were higher in the sedentary MSG-rats compared to the sedentary control; however, the exercise did not influenced its expression in the groups analyzed. CONCLUSIONS: In conclusion, regular physical activity was not capable to correct the expression of proinflammatory adipokines in MSG-obese rat adipocytes.

Swim training and the genetic expression of adipokines in monosodium glutamate-treated obese rats

Objective The aim of this study was to evaluate the genetic expression of adipokines in the adipocytes of monosodium glutamate (MSG)-treated obese rats submitted to physical activity.Materials and methods Obesity was induced by neonatal MSG administration. Exercised rats (MSG and control) were subjected to swim training for 30 min for 10 weeks, whereas their respective controls remained sedentary. Total RNA was obtained from sections of the mesenteric adipose tissue of the rats. mRNA levels of adiponectin (Adipoq), tumor necrosis factor alpha (Tnf), peroxisome proliferator-activated receptor alpha (Ppara), and peroxisome proliferator-activated receptor gamma (Pparg) adipokines were quantified by quantitative Real-Time Polymerase Chain Reaction (qRT-PCR).Results In the exercise-trained control group, the expression of Adipoq increased compared to the sedentary control, which was not observed in the MSG-obese rats. Increased levels of Tnf in MSG-obese rats were not reversed by the swim training. The expression of Ppara was higher in sedentary MSG-obese rats compared to the sedentary control. Swimming increased this adipokine expression in the exercise-trained control rats compared to the sedentary ones. mRNA levels of Pparg were higher in the sedentary MSG-rats compared to the sedentary control; however, the exercise did not influenced its expression in the groups analyzed.Conclusions In conclusion, regular physical activity was not capable to correct the expression of proinflammatory adipokines in MSG-obese rat adipocytes.

Identification and chromosome mapping of repetitive elements in the Astyanax scabripinnis (Teleostei: Characidae) species complex.

Most part of the eukaryotic genome is composed of repeated sequences or multiple copies of DNA, which were considered as "junk DNA", and may be associated to the heterochromatin. In this study, three populations of Astyanax aff. scabripinnis from Brazilian rivers of Guaratinguetá and Pindamonhangaba (São Paulo) and a population from Maringá (Paraná) were analyzed concerning the localization of the nucleolar organizer regions (Ag-NORs), the As51 satellite DNA, the 18S ribosomal DNA (rDNA), and the 5S rDNA. Repeated sequences were also isolated and identified by the Cot - 1 method, which indicated similarity (90%) with the LINE UnaL2 retrotransposon. The fluorescence in situ hybridization (FISH) showed the retrotransposon dispersed and more concentrated markers in centromeric and telomeric chromosomal regions. These sequences were co-localized and interspaced with 18S and 5S rDNA and As51, confirmed by fiber-FISH essay. The B chromosome found in these populations pointed to a conspicuous hybridization with LINE probe, which is also co-located in As51 sequences. The NORs were active at unique sites of a homologous pair in the three populations. There were no evidences that transposable elements and repetitive DNA had influence in the transcriptional regulation of ribosomal genes in our analyses.

Construction and characterization of a repetitive DNA library in Parodontidae (Atinopterygii:Characiformes): a genomic and evolutionary approach to the degeneration of the w sex cromosome.

Repetitive DNA sequences, including tandem and dispersed repeats, comprise a large portion of eukaryotic genomes and are important for gene regulation, sex chromosome differentiation, and karyotype evolution. In Parodontidae, only the repetitive DNAs WAp and pPh2004 and rDNAs were previously studied using fluorescence in situ hybridization. This study aimed to build a library of repetitive DNA in Parodontidae. We isolated 40 clones using Cot-1; 17 of these clones exhibited similarity to repetitive DNA sequences, including satellites, minisatellites, microsatellites, and class I and class II transposable elements (TEs), from Danio rerio and other organisms. The physical mapping of the clones to chromosomes revealed the presence of a satellite DNA, a Helitron element, and degenerate short interspersed element (SINE), long interspersed element (LINE), and tc1-mariner elements on the sex chromosomes. Some clones exhibited dispersed signals; other sequences were not detected. The 5S rDNA was detected on an autosomal pair. These elements likely function in the molecular degeneration of the W chromosome in Parodontidae. Thus, the location of these elements on the chromosomes is important for understanding the function of these repetitive DNAs and for integrative studies with genome sequencing. The presented data demonstrate that an intensive invasion of TEs occurred during W sex chromosome differentiation in the Parodontidae.

Hipertensão arterial de difícil controle e o polimorfismo A1166C do gene AT1 / Difficult-to-treat hypertension and AT1 A1166C gene polymorphism

Fundamentos: Polimorfismos presentes em genes que codificam proteínas do sistema renina-angiotensina aldosterona (SRAA) estão associados com o quadro de hipertensão arterial sistêmica (HAS) em algumas populações. Estudos demonstram a relação entre o polimorfismo A1166C no gene do receptor tipo 1 da angiotensina II (AT1) com a HAS, mas os dados ainda são controversos. Objetivo: Analisar a presença deste polimorfismo em pacientes portadores de HAS resistente da região dos Campos Gerais (PR), Brasil. Materiais e Métodos: Grupos de pacientes com hipertensão de fácil (G1) (n = 34) e difícil controle medicamentoso (G2) (n = 39) foram analisados quanto ao polimorfismo mencionado, utilizando-se a técnica de Polymerase Chain Reaction­ Restriction Fragment Lenght Polymorphism (PCR-RFLP). Os pacientes foram categorizados em três genótipos: AA, AC e CC. As frequências alélicas e genotípicas foram calculadas para cada grupo e os dados confrontados com as características metabólicas e antropométricas dos indivíduos. Resultados: não houve diferença entre os grupos quanto a sexo e idade. O índice de massa corporal (IMC), pressão arterial sistólica (PAS), diastólica (PAD) e número de anti-hipertensivos utilizados foram maiores no G2. Asfrequências alélicas e genotípicas mostraram-se semelhantes entre os grupos (p > 0,05). Conclusão: Nesta população, este polimorfismo não está associado ao fácil ou difícil controle da pressão arterial (PA). Possivelmente, outros fatores devem estar influenciando a HAS nestes pacientes

Background: Polymorphisms in genes encoding proteins of the renin-angiotensin-aldosterone system (RAAS) are associated with systemic arterial hypertension (SAH) in some populations. Some reports demonstrated the relationship between the angiotensin II type 1 receptor (AT1) A1166C gene polymorphism with SAH, but the data are still controversial. Objective: To analyze the presence of this polymorphism in patients porting difficult-to-treat SAH from Campos Gerais region (PR), Brazil. Materials and Methods: Groups of patients porting hypertension easy (G1) (n = 34) and difficult-to-treat using drugs (G2) (n = 39) were analyzed according to the polymorphism mentioned, using the Polymerase Chain Reaction­ Restriction Fragment Lenght Polymorphism (PCR-RFLP) technique. The patients were categorized into three genotypes: AA, AC and CC. The allele and genotype frequencies were calculated and the results were compared with metabolic and anthropometric characteristics of the patients. Results: There was no difference between groups regarding gender and age. The body mass index (BMI), systolic and diastolic blood pressures and the number of antihypertensive drugs were higher in G2. The allele and genotype frequencies were similar between the groups (p > 0.05). Conclusions: In this population, the polymorphism analyzed is not associated with easy or difficult-to-treat SAH. Possibly, other factors are influencing the hypertension in these patients

Relação do polimorfismo C825T do gene GNB3 e hipertensão arterial sistêmica de difícil controle / Relationship between C825T polymorphism of the GNB3 gene and dificult-to-treat hypertension

Fundamentos: O polimorfismo C825T do gene GNB3 está associado à hipertensão arterial sistêmica (HAS) em algumas populações já analisadas, porém alguns estudos se mostram controversos no que se refere a esta relação. Objetivo: Avaliar a relação do polimorfismo C825T do gene GNB3 com a HAS de difícil controle medicamentoso em hipertensos de Campos Gerais, PR - Brasil. Métodos: Em relação ao polimorfismo C825T de GNB3, foram determinados os genótipos de 60 hipertensos, os quais foram estratificados em dois grupos (fácil e difícil controle medicamentoso), por meio da técnica de PCR-RFLP (Polymerase Chain Reaction - Restriction Fragment Lenght Polymorphism). Foram avaliadas as frequências alélicas e genotípicas, utilizando-se o teste do qui-quadrado de Pearson, com correção de Yates e odds ratio (OR). Resultados: Não houve diferenças entre os grupos, quando comparadas as frequências alélicas e genotípicas, indicando que a população está em equilíbrio. A probabilidade de o paciente possuir o polimorfismo e a HAS de difícil controle foi 53,5 % (OR=1,15; IC95 % = 0,41-3,26), analisando-se os genótipos. Já a análise dos alelos, separadamente, mostrou uma associação de 55,4 % (OR=1,24; IC95 % = 0,59-2,57). Conclusão: Nesta população não foi encontrada relação entre o polimorfismo C825T do gene GNB3 e a HAS de difícil controle, indicando que outros fatores estão influenciando a manifestação dessa doença nestes pacientes.

Background: C825T polymorphism of the GNB3 gene is associated with systemic arterial hypertension (SAH) in some studied populations, although certain studies are controversial in terms of this relationship. Objective: To evaluate the relationship between C825T polymorphism of the GNB3 gene and difficult-to-treat SAH among hypertensive patients in Campos Gerais, Paraná State, Brazil. Methods: With regard to C825T polymorphism of the GNB3 gene, the genotypes were defined for sixty hypertensive patients divided in 2 groups (easy and difficult-to-treat with drugs), using the Polymerase Chain Reaction - Restriction Fragment Length Polymorphism (PCR-RFLP) technique. The allele and genotype frequencies were assessed through the Pearson chi-square test, with Yates correction and odds ratio (OR). Results: There were no differences between the groups when comparing the allele and genotype frequencies, indicating that the population is in equilibrium. The probability that a patient has polymorphism with difficult-to-treat SAH reached 53.5% (OR=1.15, 95%CI = 0.41-3.26), analyzing the genotypes. A separate allele analysis showed an association of 55.4% (OR=1.24, 95%CI = 0.59-2.57). Conclusion: No relationship was found in this population between C825T polymorphism of the GNB3 gene and difficult-to-treat SAH, indicating that other factors are influencing the appearance of this disease among these patients.

Cytogenetic analysis in the neotropical fish Astyanax goyacensis Eigenmann, 1908 (Characidae, incertae sedis): karyotype description and occurrence of B microchromosomes.

BACKGROUND: B chromosomes, also known as supernumerary or accessory chromosomes, are additional chromosomes over the standard complement found in various groups of plants and animals. We investigated the presence of, and characterized, supernumerary microchromosomes in Astyanax goyacensis using classical and molecular cytogenetic methods. FINDINGS: Three specimens possessed 2n = 50 chromosomes (8m + 26sm + 8st + 8a), and two specimens contained 1 to 9 additional B microchromosomes varying intra- and inter-individually. Chromosome painting with a B chromosome-specific probe yielded signals for several B microchromosomes, with one exhibiting no markings. Acrocentric chromosomes of the standard complement were also painted. Fluorescence in situ hybridization (FISH) using ribosomal probes located two chromosome pairs carrying 18S rDNA marked on the short arm, and one pair carrying 5S rDNA with pericentromeric markings. One chromosome was observed in synteny with 18S cistrons. CONCLUSION: These data contribute to knowledge of the karyotype evolution, the origin of B chromosomes, and to an understanding of the functionality of rDNA.

Repetitive sequences associated with differentiation of W chromosome in Semaprochilodus taeniurus.

The possible origins and differentiation of a ZZ/ZW sex chromosome system in Semaprochilodus taeniurus, the only species of the family Prochilodontidae known to possess heteromorphic sex chromosomes, were examined by conventional (C-banding) and molecular (cross-species hybridization of W-specific WCP, Fluorescence in situ hybridization (FISH) with telomere (TTAGGG)n, and Rex1 probes) cytogenetic protocols. Several segments obtained by W-specific probe were cloned, and the sequences localized on the W chromosome were identified by DNA sequencing and search of nucleotide collections of the NCBI and GIRI using BLAST and CENSOR, respectively. Blocks of constitutive heterochromatin in chromosomes of S. taeniurus were observed in the centromere of all autosomal chromosomes and in the terminal, interstitial, and pericentromeric regions of the W chromosome, which did not demonstrate interstitial telomeric sites with FISH of the telomere probe. The Rex1 probe displayed a compartmentalized distribution pattern in some chromosomes and showed signs of invasion of the pericentromeric region in the W chromosome. Chromosomal painting with the W-specific WCP of S. taeniurus onto its own chromosomes showed complete staining of the W chromosome, centromeric sites, and the ends of the Z chromosome, as well as other autosomes. However, cross-species painting using this WCP on chromosomes of S. insignis, Prochilodus lineatus, and P. nigricans did not reveal a proto-W element, but instead demonstrated scattered positive signals of repetitive DNAs. Identification of the W-specific repetitive sequences showed high similarity to microsatellites and transposable elements. Classes of repetitive DNA identified in the W chromosome suggested that the genetic degeneration of this chromosome in S. taeniurus occurred through accumulation of these repetitive DNAs.

New insights on the origin of B chromosomes in Astyanax scabripinnis obtained by chromosome painting and FISH.

Chromosome painting (CP) with a probe of B chromosome obtained by microdissection and fluorescence in situ hybridization (FISH) with probes of As51 satellite DNA, C( o )t-1 DNA, and 18S and 5S rDNA confirmed sharing of some repetitive DNA but not rDNA between A and B chromosomes in the fish Astyanax scabripinnis. Meiotic analysis revealed a pachytene B chromosome bivalent nearly half the size of its mitotic configuration, suggesting a self-pairing of B chromosome arms. Such an isochromosome nature of somatic B chromosome was further evidenced by CP and FISH. All the findings obtained suggest (i) intraspecific origin of B chromosome, and (ii) evolutionary enrichment of repetitive DNA classes, especially those contained in the C( o )t-1 and the As51 probes, in B chromosome. However, the precise origin of B chromosome in the present species remains to be elucidated by further molecular cytogenetic analysis because of painting of some A chromosome regions with the B chromosome-derived probe.