Ethnicity and glutathione S-transferase (GSTM1/GSTT1) polymorphisms in a Brazilian population.

The distribution of polymorphisms related to glutathione S-transferases (GST) has been described in different populations, mainly for white individuals. We evaluated the distribution of GST mu (GSTM1) and theta (GSTT1) genotypes in 594 individuals, by multiplex PCR-based methods, using amplification of the exon 7 of CYP1A1 gene as an internal control. In São Paulo, 233 whites, 87 mulattos, and 137 blacks, all healthy blood-donor volunteers, were tested. In Bahia, where black and mulatto populations are more numerous, 137 subjects were evaluated. The frequency of the GSTM1 null genotype was significantly higher among whites (55.4%) than among mulattos (41.4%; P = 0.03) and blacks (32.8%; P < 0.0001) from São Paulo, or Bahian subjects in general (35.7%; P = 0.0003). There was no statistically different distribution among any non-white groups. The distribution of GSTT1 null genotype among groups did not differ significantly. The agreement between self-reported and interviewer classification of skin color in the Bahian group was low. The interviewer classification indicated a gradient of distribution of the GSTM1 null genotype from whites (55.6%) to light mulattos (40.4%), dark mulattos (32.0%) and blacks (28.6%). However, any information about race or ethnicity should be considered with caution regarding the bias introduced by different data collection techniques, specially in countries where racial admixture is intense, and ethnic definition boundaries are loose. Because homozygous deletions of GST gene might be associated with cancer risk, a better understanding of chemical metabolizing gene distribution can contribute to risk assessment of humans exposed to environmental carcinogens.

Ethnicity and glutathione S-transferase (GSTM1/GSTT1) polymorphisms in a Brazilian population

The distribution of polymorphisms related to glutathione S-transferases (GST) has been described in different populations, mainly for white individuals. We evaluated the distribution of GST mu (GSTM1) and theta (GSTT1) genotypes in 594 individuals, by multiplex PCR-based methods, using amplification of the exon 7 of CYP1A1 gene as an internal control. In São Paulo, 233 whites, 87 mulattos, and 137 blacks, all healthy blood-donor volunteers, were tested. In Bahia, where black and mulatto populations are more numerous, 137 subjects were evaluated. The frequency of the GSTM1 null genotype was significantly higher among whites (55.4 percent) than among mulattos (41.4 percent; P = 0.03) and blacks (32.8 percent; P < 0.0001) from São Paulo, or Bahian subjects in general (35.7 percent; P = 0.0003). There was no statistically different distribution among any non-white groups. The distribution of GSTT1 null genotype among groups did not differ significantly. The agreement between self-reported and interviewer classification of skin color in the Bahian group was low. The interviewer classification indicated a gradient of distribution of the GSTM1 null genotype from whites (55.6 percent) to light mulattos (40.4 percent), dark mulattos (32.0 percent) and blacks (28.6 percent). However, any information about race or ethnicity should be considered with caution regarding the bias introduced by different data collection techniques, specially in countries where racial admixture is intense, and ethnic definition boundaries are loose. Because homozygous deletions of GST gene might be associated with cancer risk, a better understanding of chemical metabolizing gene distribution can contribute to risk assessment of humans exposed to environmental carcinogens.

Analysis of DNA in minute volumes of blood from stains and crusts.

As the first step, the locus D1S80 was amplified by the polymerase chain reaction technique from genomic DNA extracted from artificial bloodstains and crusts with different amount of blood (32 microl, 16 microl, 8 microl, 4 microl, 2 microl, and 1 microl). In all samples of bloodstains and crusts, identification by DNA analysis was possible. As the second step, the locus HLA-DQA1 was amplified from genomic DNA extracted from diluted blood samples (640, 320, 160, 80, 40, 20, 10, and 5 leukocytes). DNA amplification was possible in diluted blood samples with at least 10 leukocytes. Considering the conditions in which the present study was carried out, it was possible to conclude that 1 microl of bloodstains or crusts was enough for identification. It was also concluded that five leukocytes are not enough material to render consistent DNA identification.

Parentage testing on blood crusts from firearms projectiles by DNA typing settles and insurance fraud case.

We describe a case of a fraudulent insurance claim. The family of an adult white male (DLF) notified the police of their son's disappearance. After a few weeks, a corpse that presented characteristics similar to those of the DLF was found in advanced stages of decay and was identified by the family as being DLF. The family then filed a claim for the life insurance that DLF had taken out just before he disappeared. Suspicions were raised about the identification of the corpse, because it had been done only visually, and because the insurance policy had been taken out just prior to DLF's disappearance. The insurance company requested a postmortem examination for identification. As the corpse had been cremated immediately after identification by the family, the biological material that was encrusted on the two projectiles removed from the body was used for analysis. The blood crusts provided enough genomic DNA for us to carry out PCR base typing of HLA-DQA1, D1S80, HUMCSF1PO, HUMTPOX, HUMTH01, D3S1744, D12S1090, D18S849, and amelogenin. Results from all loci typing from the corpse presumed to be that of DLF were then compared with that of his alleged biological parents, revealing genetic incompatibility.

Allele and genotype frequencies for D1S80 locus in a Brazilian population sample.

Gene and genotype frequencies in relation to the D1S80 locus were determined in a sample of 197 unrelated individuals (144 Caucasians and 53 Mulattoes), living in the city of São Paulo, Brazil. The Mulatto group was composed by mixed individuals who presented at least one negroid physical characteristic or declared themselves to be of mixed (Black-White) ancestry. Nineteen different alleles were detected in the Caucasian sample and 15 among Mulattoes. Alleles 18 and 24 were found to be the most common ones in the Caucasian population with frequencies of 0.173 and 0.357 respectively; the sample heterozygote frequency was estimated in 0.824. Alleles 18, 24, and 28 were found to be the most common alleles among Mulattoes with respective frequencies of 0.150, 0.349, and 0.113; the sample heterozygote frequency was 0.759. Fifty-five different genotypes were detected among Brazilian Caucasians whereas the respective figure among Mulattoes was 31. No significant deviations from Hardy-Weinberg equilibrium were found in both population samples.

Post-mortem forensic identity testing: application of PCR to the identification of fire victim.

CONTEXT: DNA analysis has been used with success in the identification of carbonized corpses and victims of large accidents. The analysis requires relatives of crash victims to donate blood for analysis. The relatives are generally willing contribute to the identification by giving a blood sample. OBJECTIVE: To describe the use of the polymerase chain reaction (PCR) for genetic characterization of one victim extensively burned by fire. DESIGN: Case report. CASE REPORT: DNA was extracted from blood of the cardiac chamber, and 15 different loci (D1S80, ApoB, D17S30, D3S1744, D18S849, D12S1090, FGA, D7S820, D1S533, D9S304, HUMCSF1PO, HUMTPOX, HUMTHO1, amelogenin and HLA-DQA1) were analyzed using the PCR technique. Results from all loci typing of the corpse were then compared to that of his alleged biological parents, revealing a genetic compatibility.

Cytochrome P450-2E1 and glutathione S-transferase mu polymorphisms among Caucasians and mulattoes from Brazil.

The variable interindividual ability to metabolize environmental toxicants, also known as metabolic polymorphism, may be of substantial importance in the modulation of cancer risk. The ethnic distribution of these polymorphisms could be interesting in order to establish an association with cancer risk or even to establish selective advantage of some genotypes. Cytochrome P450 2E1 (CYP2E1) is a secondary enzyme that can metabolize ethanol, and glutathione S-transferase (GSTM1) is thought to be involved in the detoxification of epoxides and polycyclic aromatic hydrocarbons. Mutation in these genes was investigated in a random sample of healthy subjects from São Paulo, Brazil, which included 206 Caucasians and 86 mulattoes. Pst I restriction fragment length polymorphism (RFLP) in the 5'-flanking region of the CYP2E1 gene has been identified in 10.2% of Caucasian individuals and in 11.6% of mulattoes. For GSTM1 the frequency of the null genotype was significantly higher in Caucasian individuals (60.2%) than in mulattoes (41.9%). Allele frequencies were (1) CYP2E1 locus: P = 0.949, q = 0.051, se(p) = se(q) = 0.011 among Caucasians; and p = 0.942; q = 0.058; se(P) = se'(q) = 0.018 among mulattoes; and (2) GSTM1 locus: p = 0.224, q = 0.776, se(p) = se(q) = 0.022 among Caucasians; and p = 0.353; q = 0.647; se(p) = se(q) = 0.041 among mulattoes.

Gene and genotype frequencies for HLA-DQA1 in Caucasians and Mulattoes in Brazil.

Gene and genotype frequencies of the HLA-DQA1 locus were determined in a sample of 197 unrelated individuals (144 Caucasians and 53 Mulattoes), living in the city of São Paulo, Brazil. The Mulatto group consisted of mixed individuals who presented at least one negroid physical characteristic or declared themselves to be of mixed ancestry. A total of six different alleles were identified with frequencies ranging from 0.087 to 0.316 in the Caucasian population and from 0.066 to 0.330 in the Mulatto population. We observed an increased frequency of allele 1.2 among Mulattoes in relation to Caucasians. The sample heterozygote frequency was 0.722 among Caucasians and 0.736 among Mullatoes. No significant deviations from Hardy-Weinberg equilibrium were found either in the Caucasian or in the Brazilian Mullato population samples.

A critical appraisal of the value of vaginal acid phosphatase determination for the estimation of post-coital time.

A careful literature review of the use of vaginal fluid acid phosphatase levels as a means to estimate post-coital time disclosed several inconsistencies. In this study, acid phosphatase levels were determined in vaginal fluid samples obtained from 200 women whose post-coital time was known. No statistical significance (at 5% probability levels) was found when vaginal acid phosphatase levels were correlated with post-coital time.

Utilization of cytogenetic technics in paternity investigation.

The joint analysis of several genetic markers in cases of paternity investigation renders possible a cumulative probability of 99.7% of chance of exclusion of a falsely accused father. The role of heteromorphisms of the Y chromosome size was appraised in this work, with more than one genetic marker, in 20 expertise examinations in paternity investigation, where the children were male. The results found with this method, in association with the research on erythrocytic and leucocytic antigens showed the exclusion of two falsely accused men. Cytogenetics analysis with Giemsa stain in combination with leukocyte (HLA system) and erythrocyte antigens investigation demonstrated the exclusion of two men falsely accused.

[Sex determination in blood stains through identification of Y-chromatin: medico-legal application]. / Diagnóstico do sexo em crostas de sangue através da identificação da cromatina Y: aplicação médico-legal.

The Y-chromatin is visualized in human interphase nuclei, corresponding to the distal portion of the Y-chromosome, which shows marked fluorescence after staining with quinacrine. This report describes the results of sex determination on blood smears fixed in methanol and blood stains left at room temperature for 13 weeks (1st report), and for 10 months (2nd report). Blind trials showed that a reliable sex determination of blood stains on glass left for at least six months is possible. The application of this method in forensic practice is discussed.

Papel das alteraçöes cromossômicas na etiologia da esterilidade masculina / Role of chromosome changes in the etiology of male sterility

Anomalias cromossômicas no homem podem levar à esterilidade. O estudo citogenético de 40 pacientes com histórico de azoospermia ou oligospermia severa foi realizado visando estimar a freqüência de anomalias cromossômicas na etiologia da esterilidade primária e avaliar se esse exame deve ser recomendado como subsídio para o diagnóstico em nosso meio. A constituiçäo cromossômica normal 46,XY estava presente em 31 pacientes; quatro eram portadores de anomalias cromossômicas: cariótipo 47,XXY; 47,XYY; 45,XY,t (13q14q); homem XX; três apresentavam instabilidade cromossômica e dois a variante cromossômica Gp+. A etiologia da esterilidade primária foi determinada em 10% dos pacientes. Discutiu-se o papel das instabilidades cromossômicas e das variantes cromossômicas. O estudo citogenéticos revelou-se relevante como subsídio ao diagnóstico