RESUMO
Tuberculosis, a potentially fatal infectious disease, affects millions of individuals annually worldwide. Human protective immunity that contains tuberculosis after infection has not been clearly defined. To gain insight into host genetic factors, nonparametric linkage analysis was performed using high-throughput microarray-based single nucleotide polymorphism (SNP) genotyping platform, a GeneChip array comprised 59 860 bi-allelic markers, in 93 Thai families with multiple siblings, 195 individuals affected with tuberculosis. Genotyping revealed a region on chromosome 5q showing suggestive evidence of linkage with tuberculosis (Z(lr) statistics=3.01, logarithm of odds (LOD) score=2.29, empirical P-value=0.0005), and two candidate regions on chromosomes 17p and 20p by an ordered subset analysis using minimum age at onset of tuberculosis as the covariate (maximum LOD score=2.57 and 3.33, permutation P-value=0.0187 and 0.0183, respectively). These results imply a new evidence of genetic risk factors for tuberculosis in the Asian population. The significance of these ordered subset results supports a clinicopathological concept that immunological impairment in the disease differs between young and old tuberculosis patients. The linkage information from a specific ethnicity may provide unique candidate regions for the identification of the susceptibility genes and further help elucidate the immunopathogenesis of tuberculosis.
Assuntos
Povo Asiático/genética , Ligação Genética , Genoma Humano , Polimorfismo de Nucleotídeo Único , Tuberculose/genética , Idade de Início , Alelos , Criança , Cromossomos Humanos Par 17 , Cromossomos Humanos Par 20 , Cromossomos Humanos Par 5 , Família , Marcadores Genéticos , Haplótipos , Humanos , Escore Lod , Probabilidade , Irmãos , Estatísticas não Paramétricas , Tailândia , Tuberculose/imunologia , Adulto JovemRESUMO
The prevalence of fragile X syndrome (FXS) is approximately 7% in Thai boys with developmental delay of unknown cause. To determine if FXS might have a specific haplotype association, we analyzed 125 unrelated control subjects and 25 unrelated FXS patients using 3 microsatellites, DXS548, FRAXAC1 and FRAXE, and two single nucleotide polymorphisms, ATL1 and IVS10. FRAXAC1 and DXS548 are located approximately 7 kb and approximately 150 kb proximal to the CGG-FMR1 whereas ATL1, IVS10 and FRAXE are located approximately 5.6 kb, approximately 24.5 kb and approximately 600 kb distal to the CGG-FMR1. We found 40 haplotypes in the control group and 14 haplotypes in the FXS group. Of 14 haplotypes in the FXS group, 6 haplotypes were not found in the control group suggesting possible new mutations or admixture of immigrant haplotypes. We observed that most diverse haplotypes came from different FRAXE alleles. For this reason, we analyzed haplotypes composed from the remaining markers alone (DXS548-FRAXAC1-ATL1-IVS10). We found 2 major haplotypes (20-18-G-T and 20-19-A-C) with no significant haplotype differences between the control group (67/125 of 20-18-G-T and 25/125 of 20-19-A-C) and FXS group (16/25 of 20-18-G-T and 6/25 of 20-19-A-C). The other haplotypes found were 33/125 in the control group and 3/25 in the FXS group. The two major haplotypes associated FXS in Thai subjects were the two most common haplotypes in the normal Thai subjects. We could not prove, therefore, that there were founder effects at the FRAXA locus in Thailand. We could not, however, exclude it completely. These findings apparently contrast with most other reports on FXS founder effects in various ethnic groups.
Assuntos
Síndrome do Cromossomo X Frágil/genética , Haplótipos , Proteínas do Tecido Nervoso/genética , Proteínas de Ligação a RNA , Alelos , Southern Blotting , DNA/genética , Proteína do X Frágil da Deficiência Intelectual , Frequência do Gene , Humanos , Repetições de Microssatélites , Polimorfismo de Nucleotídeo Único , Tailândia , Repetições de Trinucleotídeos/genéticaRESUMO
Melioidosis is a potentially lethal infection of humans and animals in Southeast Asia and northern Australia. Current methods for detection of the causative organism, Burkholderia pseudomallei, lack both speed and sensitivity. We report the development of a highly sensitive polymerase chain reaction-based method that can detect as few as 35 colony-forming units of B. pseudomallei/mL in saline suspensions. This polymerase chain reaction test also detected the presence of B. pseudomallei DNA in culture-negative splenic tissue obtained from mice infected with the organism, but without clinical evidence of disease. Specificity has been confirmed using a variety of pathogenic and nonpathogenic organisms, including B. mallei, B. cepacia, and Pseudomonas species. The clinical usefulness of this test should be assessed prospectively and compared with conventional diagnostic techniques.
Assuntos
Burkholderia pseudomallei/genética , Burkholderia pseudomallei/isolamento & purificação , Reação em Cadeia da Polimerase/métodos , Animais , Sequência de Bases , Contagem de Colônia Microbiana , Primers do DNA/genética , DNA Bacteriano/análise , DNA Bacteriano/genética , Modelos Animais de Doenças , Estudos de Avaliação como Assunto , Humanos , Melioidose/diagnóstico , Melioidose/microbiologia , Camundongos , Reação em Cadeia da Polimerase/estatística & dados numéricos , Sensibilidade e Especificidade , Especificidade da Espécie , Baço/microbiologia , Fatores de TempoRESUMO
Fever almost invariably accompanies uncomplicated falciparum malaria. In a randomized, double-'blind' study, we compared a single dose of ibuprofen (10 mg/kg, n = 8) with paracetamol (15 mg/kg, n = 8) for the treatment of fever > 38.5 degrees C due to uncomplicated falciparum malaria. Ibuprofen was significantly more effective than paracetamol in lowering temperatures throughout the first 4.5 h after dosing (P = 0.016) and should be considered as an antipyretic agent in the management of uncomplicated falciparum infections, providing there is no contraindication to its use.
Assuntos
Acetaminofen/uso terapêutico , Analgésicos não Narcóticos/uso terapêutico , Febre/tratamento farmacológico , Ibuprofeno/uso terapêutico , Malária Falciparum/complicações , Temperatura Corporal/efeitos dos fármacos , Contraindicações , Método Duplo-Cego , Feminino , Febre/etiologia , Humanos , Masculino , Fatores de TempoRESUMO
PURPOSE: To study the clinical features of Leber's hereditary optic neuropathy (LHON) in Thai patients as compared with patients in the United States, Europe, and other Asian countries. METHODS: The blood mitochondrial DNA of patients from 19 Thai pedigree families was studied for LHON mutation by restriction enzyme analysis. RESULTS: Mitochondrial mutation at nucleotide position 11778 was detected in 37 affected patients and 21 unaffected maternal relatives. Ten of the 19 families were sporadic in transmission. The male preponderance in affected patients was 76%. The onset of visual loss ranged from 6 to 53 years of age (mean = 21.5 years). Of the 31 patients whose eyes were affected bilaterally, 48.4% developed visual loss simultaneously. Unilateral visual loss was found in 2 patients but 1 already had a blind eye resulting from trauma. Onset interval between eyes was up to 12 months (mean = 2.3 months). No associated heart disease or neurological disorder was detected in our pedigrees. Hyperemic disc, retinal telangiectasia, and tortuosity of vessels appeared on ophthalmoscopy in 29% of the patients. Final visual outcome was 0.1, or worse in 82.3%, with a mean follow-up period of 19.5 months. CONCLUSION: The clinical features of LHON in Thai patients are similar to those found in patients harboring the 11778 mutation in the United States, Europe, and Japan. However, although there is a male predominance in all populations studied, this is not so marked in the European and Thai populations.
Assuntos
Atrofia Óptica Hereditária de Leber/epidemiologia , Adolescente , Adulto , Idade de Início , Criança , Análise Mutacional de DNA , DNA Mitocondrial/genética , Europa (Continente)/epidemiologia , Feminino , Humanos , Japão/epidemiologia , Masculino , Pessoa de Meia-Idade , Mutação , Atrofia Óptica Hereditária de Leber/genética , Linhagem , Tailândia/epidemiologia , Estados Unidos/epidemiologiaRESUMO
Fragile X syndrome (FXS) is the most common form of inherited mental retardation. We screened for FXS in 237 Thai males (age < or = 15 years) with developmental delay of unknown cause. We found 16 (6.8%) to have FXS using standard molecular analysis. Wc then studied the extended families of these 16 FXS subjects and 4 other independently ascertained FXS cases. We found that there were at least 35 affected males and 8 affected females. In addition we found that there were at least 31 premutation carrier females and 4 premutation males. The CGG repeats numbers in these premutation individuals ranged from 60 to 125. By comparison, the normal CGG repeats were 19-50 with a heterozygosity of 67.2% in 337 randomly selected males. This study providcs insight into the high incidence of FXS in developmentally delayed Thai males and points the way toward the means of prevention of mental retardation by genetic counseling and prenatal diagnosis.
Assuntos
Síndrome do Cromossomo X Frágil/diagnóstico , Testes Genéticos , Adolescente , Criança , Pré-Escolar , Feminino , Síndrome do Cromossomo X Frágil/epidemiologia , Síndrome do Cromossomo X Frágil/genética , Triagem de Portadores Genéticos , Humanos , Lactente , Masculino , Mutação , Reação em Cadeia da Polimerase , Polimorfismo Genético , Tailândia/epidemiologia , Repetições de TrinucleotídeosRESUMO
Circulating HGV-RNA was determined in 117 patients with HCV-related chronic liver disease and in 200 healthy blood donors. The patients, aged 50.8+/-13.8 years, were classified as chronic hepatitis (CH; n = 82), liver cirrhosis (n = 25) and hepatocellular carcinoma (HCC; n = 10). HGV-RNA was detected in 5 (4.3%) patients, all with CH and in 10 (5%) of blood donors. The majority of all groups (52% to 70%) were infected with HCV genotype II/1b, including 4/5 patients with HGV co-infection. Of 5 patients with HGV co-infection, 4 were positive for anti-HBs and anti-HBc and none exhibited jaundice. A 24-week course of interferon treatment with 12-month follow-up was achieved in 27 patients with chronic active hepatitis, including 3 with HGV co-infection. Of these, 55.6% responded to the therapy, but only 6/27 (22.2%) patients were sustained responders. The majority of sustained responders were HCV genotype III/2a (4/6) while genotype II/1b was found in the majority of patients with relapse (7/9) and non-responders (9/12). At the 48- month follow up, 2/6 sustained responders (one with HGV co-infection) became HCV RNA positive. These results show that the prevalence of HGV infection in HCV-related chronic liver disease is low, as in the general population, and is found in younger patients with chronic hepatitis. HGV coinfection does not interfere with clinical severity, disease progression or response to interferon in patients with HCV-related chronic liver disease. The favorable factors ofinterferon treatment for HCV infection are young age, low HCV-RNA levels and HCV genotype III/2a.
Assuntos
Antivirais/uso terapêutico , Carcinoma Hepatocelular/virologia , Flaviviridae/genética , Hepatite Viral Humana/terapia , Interferon-alfa/uso terapêutico , Cirrose Hepática/virologia , Neoplasias Hepáticas/virologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Flaviviridae/isolamento & purificação , Genótipo , Hepacivirus/genética , Hepacivirus/isolamento & purificação , Hepatite C Crônica/complicações , Hepatite C Crônica/genética , Hepatite C Crônica/terapia , Hepatite Viral Humana/complicações , Hepatite Viral Humana/epidemiologia , Humanos , Testes de Função Hepática , Masculino , Pessoa de Meia-Idade , RNA Viral/análiseRESUMO
Although fine needle aspiration cytology (FNAC) is an effective mean for the diagnosis of cervical tuberculous lymphadenitis (CTL), it still poses a certain degree of false negative and false positive. The objective of this study was to determine the efficiency of polymerase chain reaction (PCR) in combination with fine needle aspiration cytology in the diagnosis of CTL. Thirty three patients who presented with enlarged cervical lymph nodes, and were clinically suggestive of CTL were included in the study. Fine needle aspiration or surgical biopsy of lymph nodes was performed, the specimens were studied for cytology, acid fast bacilli stain, culture for mycobacteria and PCR technique. The sensitivity and specificity of FNAC was 48 per cent and 87.5 per cent respectively, while that of PCR was 84 per cent and 75 per cent respectively. When FNAC and PCR were combined, the sensitivity and specificity increased to 84 per cent and 100 per cent respectively. We concluded that FNAC in combination with the PCR technique is a fast and effective clinical diagnostic approach for CTL.
Assuntos
Linfonodos/patologia , Linfadenite/diagnóstico , Mycobacterium tuberculosis/isolamento & purificação , Reação em Cadeia da Polimerase/normas , Tuberculose dos Linfonodos/diagnóstico , Adolescente , Adulto , Biópsia por Agulha/normas , Diagnóstico Diferencial , Feminino , Humanos , Linfadenite/microbiologia , Masculino , Pessoa de Meia-Idade , Pescoço , Valor Preditivo dos Testes , Tuberculose dos Linfonodos/microbiologiaRESUMO
The aim of this study was to determine a cost-effective clinical checklist for fragile X syndrome (FXS) screening in a Thai male pediatric population with developmental delay of unknown cause. We studied 179 non-FXS male patients and 27 FXS patients from 18 families (age < or = 15 years). A six-item clinical checklist was used including family history (FH), long and narrow face (F), prominent and large ears (E), attention deficit/hyperactivity (AH), autistic-like behavior (AT) and testicular volume (T). These were scored as 0 if absent, 1 if borderline, and 2 if present. All patients were tested by using PCR and/or southern blot for the FMR1 gene. We used a logistic regression model from a computer program to analyze the data (Stata, version 5.0). We used logistic regression with cluster in the same family (average score) to eliminate bias from the related FXS cases. We found that a five-item checklist, 2FH + F + 0.5E + 2AH + T = total score, was the best model. When we used this clinical checklist with a threshold of total score of 4, 78.7 per cent of the screened cases with total scores < or = 4 could be eliminated as negative cases. In addition, all positive FXS cases had total scores > 4. We propose this five-item model for FXS screening in clinical pediatric practice, particularly from Asian population settings.
Assuntos
Deficiências do Desenvolvimento/diagnóstico , Deficiências do Desenvolvimento/genética , Síndrome do Cromossomo X Frágil/diagnóstico , Síndrome do Cromossomo X Frágil/genética , Testes Genéticos/métodos , Proteínas do Tecido Nervoso/genética , Proteínas de Ligação a RNA , Adolescente , Southern Blotting , Criança , Proteína do X Frágil da Deficiência Intelectual , Humanos , Incidência , Lactente , Modelos Logísticos , Masculino , Proteínas do Tecido Nervoso/análise , Reação em Cadeia da Polimerase , Medição de Risco , Tailândia/epidemiologiaRESUMO
Fragile X syndrome, the most common cause of inherited mental retardation, is an X-linked genetic disorder caused by an expanded CGG repeat in the fragile X mental retardation 1 gene. It is characterized by mental retardation, behavioral features, and physical features, such as a long face with large protruding ears and macro-orchidism. A screening for the syndrome was conducted in a representative sample of pediatric patients, who had developmental delay or mental retardation with unknown cause, at the Child Development Clinic, Ramathibodi Hospital. The DNA test was performed on all patients using PCR and southern blot techniques. Five positive cases were detected from 114 screened subjects, and more four cases confirmed among other family members. Two of five positive families initially denied a family history of mental retardation. Among 9 cases of fragile X syndrome, four had hyperactivity and two had autistic like behavior. More than half had rather a long face or prominent ears. Three boys had macro-orchidism.
Assuntos
Síndrome do Cromossomo X Frágil/epidemiologia , Deficiência Intelectual/epidemiologia , Adolescente , Distribuição por Idade , Instituições de Assistência Ambulatorial , Criança , Pré-Escolar , Feminino , Síndrome do Cromossomo X Frágil/complicações , Síndrome do Cromossomo X Frágil/diagnóstico , Aconselhamento Genético , Hospitais Urbanos , Humanos , Deficiência Intelectual/diagnóstico , Deficiência Intelectual/etiologia , Masculino , Programas de Rastreamento , Prevalência , Estudos de Amostragem , Distribuição por Sexo , Tailândia/epidemiologiaAssuntos
Degenerações Espinocerebelares/etiologia , Trigêmeos , Fatores Etários , Família , Feminino , Humanos , Pessoa de Meia-IdadeAssuntos
Rejeição de Enxerto/prevenção & controle , Imunossupressores/uso terapêutico , Transplante de Rim/imunologia , Transplante de Pele/imunologia , Doadores de Tecidos , Gêmeos Monozigóticos , Adulto , Azatioprina/uso terapêutico , Southern Blotting/métodos , Ciclosporina/uso terapêutico , DNA/análise , Feminino , Guias como Assunto , Humanos , Masculino , Prednisolona/uso terapêuticoRESUMO
Chemokines and their receptors are key factors in the onset and progression of AIDS. Among them, accumulating evidence strongly indicates the involvement of IL-8 and its receptors, CXCR1 and CXCR2, in AIDS-related conditions. Through extensive investigation of genetic variations of the human CXCR1-CXCR2 locus, we identified a haplotype of the CXCR1 gene (CXCR1-Ha) carrying two nonsynonymous single nucleotide polymorphisms, CXCR1_300 (Met to Arg) in the N terminus extracellular domain and CXCR1_142 (Arg to Cys) in the C terminus intracellular domain. Transfection experiments with CXCR1 cDNAs corresponding to the CXCR1-Ha and the alternative CXCR1-HA haplotype showed reduced expression of CD4 and CXCR4 in CXCR1-Ha cells in human osteosarcoma cells as well as in Jurkat and CEM human T lymphocytes. Furthermore, the efficiency of X4-tropic HIV-1(NL4-3) infection was significantly lower in CXCR1-Ha cells than in CXCR1-HA cells. The results were further confirmed by a series of experiments using six HIV-1 clinical isolates from AIDS patients. A genetic association study was performed by using an HIV-1(+) patient cohort consisting of two subpopulations of AIDS with extreme phenotypes of rapid and slow progression of the disease. The frequency of the CXCR1-Ha allele is markedly less frequent in patients with rapid disease onset than those with slow progression (P = 0.0003). These results provide strong evidence of a protective role of the CXCR1-Ha allele on disease progression in AIDS, probably acting through modulation of CD4 and CXCR4 expression.
Assuntos
Síndrome da Imunodeficiência Adquirida/genética , Regulação da Expressão Gênica/genética , Variação Genética , HIV-1 , Haplótipos/genética , Receptores de Interleucina-8A/genética , Western Blotting , Antígenos CD4/metabolismo , Linhagem Celular Tumoral , Progressão da Doença , Citometria de Fluxo , Componentes do Gene , Frequência do Gene , Humanos , Imuno-Histoquímica , Polimorfismo de Nucleotídeo Único/genética , Receptores CXCR4/metabolismoRESUMO
Base pair formation between O-silyl derivatives of 8-oxoguanosine (8-OxoG) and 8-oxo-2'-deoxyguanosine (8-OxodG) with 2'-deoxyadenosine (dA), 2'-deoxycytosine (dC), 2'-deoxyguanosine (dG), and thymidine (dTHd) have been examined by NMR methods in chloroform. 8-OxoG and 8-OxodG form base pairs with all four nucleosides, suggesting that they can mimic the base pairing properties of any DNA base. In 8-OxodG.dA or 8-OxoG.dA base pairs both bases assume Hoogsteen geometry with respect to both bases. Hoogsteen and Watson-Crick base pairs are formed between 8-OxodG or 8-OxoG and either dThd or dG. Only Watson-Crick geometry is seen for 8-OxodG.dC and 8-OxoG.dC base pairs. In all base pairs the glycosidic bond of 8-OxodG or 8-OxoG is syn and anti for the base pair partner. Additional base pairing studies with the modified nucleosides 1-methyl-8-oxoguanosine (1-Me-8-oxoG), 7-methyl-8-oxoguanosine (7-Me-8-oxoG), and 8-methoxyguanosine (8-OMeG), modified nucleosides structurally related to 8-OxoG and 8-OxodG, support the proposed base pair structures and aided in the determination of base pair geometry. Association constants were determined for 8-OxoG.dN and 8-OxodG.dN (N = A, C, G, Thd) base pairs as well as the normal dTHd-A and dG.dC base pairs. The magnitude of the association constants allows the relative stabilities of the base pairs to be determined: 8-OxodGWC.dC (8-OxoGWC.dC) approximately dGWC.dC > 8-OxodGH.dG (8-OxoGH.dG) > 8-OxodGH.dA (8-OxoGH.dA) > 8-OxodGH.dThd (8-oxoGH.dThd) approximately dThd.dA. The formation of these base pairs is consistent with the known mutagenic nature of 8-oxo-2'-deoxyguanosine and with NMR studies of oligonucleotides containing the 8-oxoG modification.
Assuntos
Citosina/análogos & derivados , Desoxiadenosinas/química , Desoxiguanosina/análogos & derivados , Desoxiguanosina/química , Guanosina/análogos & derivados , Timidina/química , 8-Hidroxi-2'-Desoxiguanosina , Citosina/química , Guanosina/química , Espectroscopia de Ressonância Magnética , Metilação , Conformação de Ácido Nucleico , PrótonsRESUMO
We investigated the prevalence of a genetic variation in the factor V gene (G1691A Leiden mutation) and the prothrombin gene (G20210A) using polymerase chain reaction techniques in samples from 500 normal Thai population and among 50 unselected Thai patients with an objectively confirmed history of deep venous thrombosis. The prevalence of factor V Leiden and the prothrombin G20210A gene mutation in a group of 500 healthy controls was 0.2% in both groups (allele frequency of 0.1%). Of the 50 adult patients studied, none was a carrier of factor V Leiden or the prothrombin G20210A gene mutation. Our findings confirm that the prevalence of factor V Leiden and prothrombin G20210A gene mutation is lower among Asians than Caucasians and that the distribution of factor V Leiden is similar to that of the prothrombin G20210A variant. The low prevalence of these two mutations can, at least in part, account for the lower frequency of deep venous thrombosis reported in the Thai population. Screening for factor V Leiden and prothrombin gene mutation is of limited benefit and may not be cost-effective in Thai patients with the first episode of deep venous thrombosis.
Assuntos
Fator V/genética , Mutação Puntual , Protrombina/genética , Adolescente , Adulto , Idoso , Etnicidade/genética , Feminino , Frequência do Gene , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Prevalência , Tailândia/epidemiologia , Trombose Venosa/genética , Trombose Venosa/patologiaRESUMO
We investigated the prevalence of a genetic variation in the 5, 10-methylenetetrahydrofolate reductase (MTHFR) gene (C677T) using polymerase chain reaction techniques in a sample of 500 general Thai population and among 40 unselected Thai patients with an objectively confirmed history of deep vein thrombosis (DVT). The prevalence of the mutated homozygous and heterozygous C677T MTHFR genotype in the group of 500 healthy Thai population was 1.4 and 25.6%, respectively (allele frequency of 14.2%). Of the 40 patients studied, none were homozygotes and 15% were heterozygotes for the C677T MTHFR gene mutation (allele frequency of 7.5%). There was no significant difference in genotype frequency between patients and control groups (p = 0.09). Odds ratios for the probability of the C677T MTHFR gene mutation in the patient versus control group were 0.49 (95% CI 0. 21-1.12). These data indicated that the C677T MTHF gene mutation was not associated with DVT in the Thai population. The lower frequency of the C677T MTHFR gene mutation in our Thai population compared with reports from other studies suggests a wide heterogeneity in the 677T MTHFR genotype frequencies of the different ethnic populations even among Asians.
Assuntos
Oxirredutases atuantes sobre Doadores de Grupo CH-NH/genética , Trombose Venosa/genética , Adolescente , Adulto , Idoso , Alelos , Substituição de Aminoácidos , Feminino , Frequência do Gene , Predisposição Genética para Doença , Testes Genéticos , Variação Genética , Heterozigoto , Homozigoto , Humanos , Masculino , Metilenotetra-Hidrofolato Redutase (NADPH2) , Pessoa de Meia-Idade , Mutação , Reação em Cadeia da Polimerase , Prevalência , Fatores de Risco , Tailândia/epidemiologiaRESUMO
The biologic functions attributed to the nucleophosphoprotein p53 have been increasing in recent years. Some studies suggested that wild type p53 is responsible for cell cycle arrest brought about as a response to exposure of mammalian cells to DNA-damaging agents. This cell cycle arrest occurs in order for cells to repair the damaged macromolecules. Extensively damaged cells are also thought to undergo apoptosis via the p53-dependent or -independent signal transduction pathways. In this study, we investigated the ability of diaziridinylbenzoquinones to increase p53 levels in the human breast cancer cell line MCF-7. Diaziquone (AZQ), an anticancer agent, and its derivatives, diaziridinequinone (DZQ) and methyldiaziridinequinone (MeDZQ), induced p53 in a dose- and time-dependent manner as measured by the electrophoretic mobility shift assay. Wild type p53 induction by AZQ was suppressed when DT-diaphorase activity was inhibited by pretreating the cells with dicumarol. Aside from their potent alkylating activity, these agents also undergo redox cycling as evidenced by oxygen consumption and the production of reactive oxygen species (ROS). Inhibition of ROS production by the antioxidant enzyme catalase reduced AZQ- and DZQ-mediated p53 induction by about 45%. Thiotepa, a non-quinone aziridine-containing agent, and 1,4-benzoquinone (p-BQ), a redox cycling quinone, increased p53 levels. The nonalkylator oxygen-radical-generating agent menadione (MD) caused p53 induction only when MCF-7 cells were allowed to recover in drug-free media. On the basis of these data, we propose that the bioreductive activation of AZQ is a prerequisite for p53 induction. Moreover, the induction of p53 by AZQ requires both the quinone and the aziridine moieties of the AZQ molecule. Although AZQ and its analogues increased p53 levels in MCF-7 cells, p53 induction in these cells may not be responsible for the apoptosis seen upon treatment of MCF-7 cells with these agents. The uncoupling of p53 induction and apoptosis is evidenced by the generation of nucleosomal DNA laddering in aziridinequinone-treated T47D cells, a breast cancer cell line bearing a p53 mutation.
Assuntos
Antineoplásicos/farmacologia , Aziridinas/farmacologia , Benzoquinonas/farmacologia , Proteína Supressora de Tumor p53/biossíntese , Adenocarcinoma , Neoplasias da Mama , Humanos , Células Tumorais Cultivadas/efeitos dos fármacosRESUMO
Cystic fibrosis (CF) is the most common fatal autosomal recessive multisystem disorder, which occurs mainly in European-derived populations. The incidence of CF varies between 1 in 2000 to 3000 live-births in various ethnic groups. The disease is rare in East Asians. Here we report a 9 year old Thai male patient, who was diagnosed to have CF based on recurrent pneumonia, a slow weight gain, pancreatic insufficiency and repeatedly elevated sweat chloride levels by two different methods. A comprehensive genetic analysis showed the splicing mutation, 1898+ 1G-->T, which was apparently of maternal origin. Literature search found 39 documented cases of CF patients in East Asians. CFTR (MIM# 602421) genotyping was performed in 14 patients including our patient and in 9 of them a CF allele was identified. The findings seem to indicate that the splicing mutations, 1898+ 1G-->T and 1898+ 5G-->T are more common in East Asian CF patients.
Assuntos
Processamento Alternativo/genética , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Fibrose Cística/genética , Mutação , Sudeste Asiático , Criança , Humanos , MasculinoRESUMO
We have defined the molecular basis of normal HbA2 beta-thalassaemia associated with Hb Knossos. DNA sequence analysis of the delta globin gene in cis with beta Knossos showed deletion of a single A in codon 59 leading to a premature termination at codon 60. This delta 0/beta Knossos allele has been observed in three unrelated Egyptian families and associated with a single beta haplotype (+----++). One individual who was homozygous for the delta 0/beta Knossos allele as well as heterozygous for a non-deletional alpha thalassaemia, was completely clinically asymptomatic, while others have coinherited the delta 0/beta Knossos allele with different beta and alpha thalassaemia determinants. A study of the different genetic interactions giving rise to a spectrum of clinical phenotypes is reported.