Análise dos polimorfismos GSTM1 e GSTT1 em pacientes que desenvolveram leucemias agudas

Leukemia is a neoplasic disease that affects bone-marrow cells. In case of Acute Leukemia (AL)the proliferating cells are immature or blasts. The causes of AL are likely to involve an interaction between genetic susceptibility and environment. Polymorphisms in genes coding metabolizing/detoxification enzymes are responsible for this susceptibility. The aim of this study was to analyze polymorphisms of GSTM1 and GSTT1 genes in order to verify if they have a role in genetic susceptibility to AL. Genomic DNA from 87 patients (24 myeloblastic, 35 lymphoblastic, 28 with no specific classification) was analyzed by a multiplex PCR methodology. Patient age variation was between 6 months and 80 years old, being 35 females and 52 males. Significant increase in the prevalence of GSTT1 null genotype was detected in the patient group comparing to controls (41,37% X 23%) (P=0.005). No difference was found in the prevalence of GSTM1 null genotype between AL patients and controls (49,42% X 50%). Our results suggest that the GSTT1 genotype may be involved in genetic susceptibility to LA.A leucemia é uma neoplasia que acomete a medula óssea. No caso das Leucemias Agudas (LA), as células em proliferação são imaturas ou blastos. A etiologia das LA pode ser explicada pela combinação de fatores genéticos e ambientais. Como exemplo das influências genéticas pode-se citar polimorfismos de genes de metabolização/detoxificação. Este trabalho tem por objetivo analisar os polimorfismos dos genes GSTM1 e GSTT1 em relação à suscetibilidade de desenvolvimento de LA. O DNA genômico de 87 pacientes (24 mielóides, 35 linfóides e 28 sem classificação determinada) foi analisado pela técnica de PCR multiplex. A idade dos pacientes variou entre seis meses e 80 anos, sendo 35 femininos e 52 masculinos. Foi detectado aumento sig-nificativo da freqüência do genótipo GSTT1 nulo quando comparado com uma população controle (41,37% X 23%) (P=0.005). A freqüência do genótipo nulo para GSTM1 nos pacientes não apresentou diferença significativa com relação aos controles (49,42% X 50%). Com isso, sugerimos que o gene GSTT1 parece estar envolvido na suscetibilidade para o desenvolvimento de LA

Peptide Structure Modifications: Effect of Radical Species Generated by Controlled Gamma Ray Irradiation Approach

The present work aimed at evaluating the radiolysis effect upon a set of peptides, most of them involved in physiological functions. To generate reactive radical species, a Co-60 source (up to 15 kGy) was used for controlled gamma irradiation of some peptide solutions including derivatives attaching the stable free radical Toac (2,2,6,6-tetramethypiperidine-1-oxyl-4-amino-4-carboxylic acid). Regardless of the peptide sequence, a nonlinear and progressive degradation of a total of nine peptides was detected. The results were interpreted in the light of the half-life dose (D-1/2) parameter which represents the dose necessary for 50% peptide structure degradation. The vasoactive angiotensin II (AngII)'s analogue Ang-(1-7) showed greater stability towards gamma ray radiation than bradykinin (BK), Toac(0)-BK, Pro(4)-BK (D-1/2 around 4 and 2 kGy, respectively) which decreased to about 0.5-1.0 kGy in the case of acetyl-alpha-melanocyte-stimulating hormone (Aca-MSH) and substance P (SP). In terms of peptide structural modifications, the data acquired from different analytical methods suggested a Phe to Tyr (or its ortho and/or meta isomers) transformation as a consequence of the hydroxyl moiety insertion. Noteworthy, this effect seemed to be position-dependent as only Phe located at or near the C-terminal portion seemed to display this transformation. In contrast, Met is comparatively more easily oxidized, thus allowing to conclude that gamma irradiation may induce a complex position and/or sequence-dependent effect on peptides. As previously applied for BK, some irradiated peptides were submitted to their by-products purification, indeed a complementary target of the present approach for development of uncommon analogues for further structure-function investigation.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Univ Fed Sao Paulo, Paulista Med Sch, Dept Biophys, BR-04044020 Sao Paulo, BrazilUniv Sao Paulo, Nucl & Energy Res Inst IPEN, BR-05508000 Sao Paulo, BrazilUniv Sao Paulo, Prot Chem Ctr, BR-14049900 Ribeirao Preto, BrazilUniv Sao Paulo, Dept Mol & Cell Biol, Ribeirao Preto Med Sch, BR-14049900 Ribeirao Preto, BrazilUniv Fed Sao Paulo, Paulista Med Sch, Dept Biophys, BR-04044020 Sao Paulo, BrazilWeb of Scienc

Gamma Ray Irradiation of the Vasoactive Peptide Bradykinin Reveals a Residue- and Position-Dependent Structural Modification

In this work the effect of radical species generated by gamma ray irradiation of aqueous solution upon structure of vasoactive peptide bradykinin (BK, RPPGFSPFR) was investigated. Increasing doses of 1-15 kGy Co-60 gamma radiation were applied to BK solutions and a progressive degradation of its structure in a non-linear mode was observed. Two main peptide derivatives generated by these treatments were isolated and characterized through a combined amino acid analysis and daughter ion scanning mass spectrometry approach. Notably, it was observed that only the Phe residue located at position 8 and not 5 of BK was oxidized by reactive hydroxyl radical species given rise to Tyr(8)-BK and m-Tyr(8)-BK analogues. Comparative circular dichroism (CD) experiments of these peptides revealed that BK presents greater conformational similarity to Tyr(8)-BK than to m-Tyr(8)-BK. These results are in agreement with the biological potencies of these compounds measured in rat uterus and guinea pig ileum muscle contractile experiments. in summary, gamma irradiation of BK solutions revealed a residue- and surprisingly, position-structural modification effect of reactive radicals even in small peptides. Also of value for peptide chemistry field, the approach of applying controlled strong electromagnetic radiation in solution seems to be an alternative and unique strategy for generating, in some cases, peptides derivatives with uncommon structures and valuable for their further therapeutic potential evaluations.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Universidade Federal de São Paulo, Dept Biofis, BR-04044020 São Paulo, BrazilUniv São Paulo, Ctr Quim Proteinas, Dept Biol Celular & Mol, Fac Med, BR-14049900 Ribeirao Preto, SP, BrazilUniv São Paulo, IPEN CNEN SP, BR-05508000 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biofis, BR-04044020 São Paulo, BrazilWeb of Scienc

Characterization of Trypanosoma cruzi Strains Isolated from Chronic Chagasic Patients, Triatomines and Opossums Naturally Infected from the State of Rio Grande do Sul, Brazil

Thirty-five Trypanosoma cruzi strains were isolated from chronic chagasic patients, triatomines and opossums from different municipalities of the State of Rio Grande do Sul. Parasites were characterized by means of mice infectivity, enzyme electrophoresis and randomly amplified polymorphic DNA (RAPD) analysis. Twenty-nine strains were isolated from chagasic patients, 4 from triatomines (2 from Triatoma infestans and 2 from Panstrongylus megistus) and 2 from opossums Didelphis albiventris. Thirty-three T. cruzi strains were of low and 2 strains of high virulence in mice. Both virulent strains were isolated from P. megistus. Isoenzyme analysis of the strains showed 3 different zymodemes. Eleven strains isolated from chagasic patients and 2 from D. albiventris were Z2. Eighteen strains from patients and 2 from T. infestans were ZB and 2 T. cruzi strains isolated from P. megistus were Z1. RAPD profiles obtained with 4 random primers showed a high genetic heterogeneity of the T. cruzi strains. Zymodeme 2 and ZB strains were the more polymorphic. A band sharing analysis of the RAPD profiles of Z2 and ZB strains using 3 primers, showed a very low percentage of shared bands, 20% among 13 ZB strains and 14% among 13 Z2 strains. According to the isoenzyme results, 3 T. cruzi populations were present in State of Rio Grande do Sul. Zymodeme 2 and ZB strains were found infecting man (domiciliar transmission cycle) whereas Z1 strains were found infecting the sylvatic vector P. megistu