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1.
Rev. méd. Chile ; 148(7): 895-905, jul. 2020. tab, graf
Artigo em Espanhol | LILACS | ID: biblio-1139390

RESUMO

Background: Obstructive sleep apnea syndrome (OSAS) affects approximately 10%-20% of adults and is associated with obesity, hypertension and metabolic syndrome. Aim: To assess the prevalence and risk factors associated with OSAS in Chilean adults. Material and Methods: A standardized sleep questionnaire and respiratory polygraphy at home were conducted on adults aged 18 years or more, residing in the Metropolitan Region and enrolled in the 2016/17 National Health Survey. Results: Two-hundred and five people between 18 and 84 years old (46% men, mean age 50 years) underwent overnight respiratory polygraphy at home. The estimated obstructive sleep apnea prevalence was 49% (62% men, 31% women) considering an apnea-hypopnea index ≥ 5 respiratory events/hour, and 16% (21% men, 13% women) considering an apnea-hypopnea index ≥ 15 respiratory events/hour. The prevalence of obstructive sleep apnea continuously increased along with age for men and women, with a later onset for women. Age, gender, body mass index, cervical and waist circumference, snoring, reporting of apnea by proxies, self-reported cardiovascular and metabolic diseases such as hypertension, diabetes and dyslipidemia, were significantly associated with OSAS. No association was found with insomnia and daytime sleepiness. Conclusions: The prevalence and risk factors associated to obstructive sleep apnea syndrome were high among these adults.


Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Adulto Jovem , Apneia Obstrutiva do Sono/epidemiologia , Chile/epidemiologia , Prevalência , Fatores de Risco , Inquéritos Epidemiológicos
2.
Rev Med Chil ; 148(7): 895-905, 2020 Jul.
Artigo em Espanhol | MEDLINE | ID: mdl-33399673

RESUMO

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) affects approximately 10%-20% of adults and is associated with obesity, hypertension and metabolic syndrome. AIM: To assess the prevalence and risk factors associated with OSAS in Chilean adults. MATERIAL AND METHODS: A standardized sleep questionnaire and respiratory polygraphy at home were conducted on adults aged 18 years or more, residing in the Metropolitan Region and enrolled in the 2016/17 National Health Survey. RESULTS: Two-hundred and five people between 18 and 84 years old (46% men, mean age 50 years) underwent overnight respiratory polygraphy at home. The estimated obstructive sleep apnea prevalence was 49% (62% men, 31% women) considering an apnea-hypopnea index ≥ 5 respiratory events/hour, and 16% (21% men, 13% women) considering an apnea-hypopnea index ≥ 15 respiratory events/hour. The prevalence of obstructive sleep apnea continuously increased along with age for men and women, with a later onset for women. Age, gender, body mass index, cervical and waist circumference, snoring, reporting of apnea by proxies, self-reported cardiovascular and metabolic diseases such as hypertension, diabetes and dyslipidemia, were significantly associated with OSAS. No association was found with insomnia and daytime sleepiness. CONCLUSIONS: The prevalence and risk factors associated to obstructive sleep apnea syndrome were high among these adults.


Assuntos
Apneia Obstrutiva do Sono , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Chile/epidemiologia , Feminino , Inquéritos Epidemiológicos , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Fatores de Risco , Apneia Obstrutiva do Sono/epidemiologia , Adulto Jovem
3.
Rev. méd. Chile ; 147(12): 1543-1552, dic. 2019. tab
Artigo em Espanhol | LILACS | ID: biblio-1094188

RESUMO

Background The diagnosis of obstructive sleep apnea syndrome (OSAS) is based on nocturnal records: polysomnography or respiratory polygraphy. However, their high costs limit their use. Aim To examine the predictive value of three sleep questionnaires (STOP, STOP-Bang, Epworth Sleepiness Scale (ESS) in the screening of OSAS in Chilean adults. Material and Methods During the National Health Survey 2016/17, 205 adults aged 50.7 ± 15.0 years (46% males) living in the Metropolitan Region answered sleep questionnaires and underwent an ambulatory respiratory polygraphy. The sensitivity, specificity, positive and negative predictive values and receiver operating characteristic curves of sleep questionnaires were calculated. Results Fifty nine percent of participants had OSAS which was moderate to severe in 26%. The clinical variables associated with OSAS were age, male gender, hypertension, dyslipidemia, overweight, cervical and waist circumferences, history of regular snoring and witnessed apneas. Daytime somnolence, insomnia and unrefreshing sleep were not associated to OSAS risk. STOP, STOP-Bang and ESS questionnaires classified 64%, 71% and 12% of cases as high risk for OSAS, respectively. The STOP and STOP-Bang questionnaires had the highest sensitivity to predict OSAS (76% and 89%, respectively) while the ESS had the highest specificity (91%). Conclusions The sleep questionnaires allowed to identify the subjects at high risk for OSAS in this sample of adults from the Metropolitan Region.


Assuntos
Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Idoso , Inquéritos e Questionários , Apneia Obstrutiva do Sono/diagnóstico , População Urbana , Estudos Transversais , Reprodutibilidade dos Testes , Fatores de Risco , Curva ROC , Sensibilidade e Especificidade , Polissonografia
4.
J Cell Biochem ; 120(10): 16733-16740, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31099049

RESUMO

Trypanosoma cruzi is under the attack of reactive species produced by its mammalian and insect hosts. To survive, it must repair its damaged DNA. We have shown that a base excision DNA repair (BER)-specific parasite TcAP1 endonuclease is involved in the resistance to H2 O2 . However, a putative TcAP1 negative dominant form impairing TcAP1 activity in vitro did not show any in vivo effect. Here, we show that a negative dominant form of the human APE1 apurinic/apyrimidinic (AP) endonuclease (hAPE1DN) induces a decrease in epimastigote and metacyclic trypomastigote viability when parasites were exposed to H2 O2 . Those results confirm that TcAP1 AP endonuclease activity plays an important role in epimastigote and in infective metacyclic trypomastigote oxidative DNA damage resistance leading to parasite persistence in the insect and mammalian hosts. All along its biological cycle and in its different cellular forms, T. cruzi, the etiological parasite agent of Chagas' disease, is under the attack of reactive species produced by its mammalian and insect hosts. To survive, T. cruzi must repair their oxidative damaged DNA. We have previously shown that a specific parasite TcAP1 AP endonuclease of the BER is involved in the T. cruzi resistance to oxidative DNA damage. We have also demonstrated that epimastigotes and cell-derived trypomastigotes parasite forms expressing a putative TcAP1 negative dominant form (that impairs the TcAP1 activity in vitro), did not show any in vivo effect in parasite viability when exposed to oxidative stress. In this work, we show the expression of a negative dominant form of the human APE1 AP endonuclease fused to a green fluorescent protein (GFP; hAPE1DN-GFP) in T. cruzi epimastigotes. The fusion protein is found both in the nucleus and cytoplasm of noninfective epimastigotes but only in the nucleus in metacyclic and cell-derived trypomastigote infective forms. Contrarily to the TcAP1 negative dominant form, the ectopic expression of hAPE1DN-GFP induces a decrease in epimastigote and metacyclic trypomastigote viability when parasites were exposed to increasing H2 O2 concentrations. No such effect was evident in expressing hAPE1DN-GFP cell-derived trypomastigotes. Although the viability of both wild-type infective trypomastigote forms diminishes when parasites are submitted to acute oxidative stress, the metacyclic forms are more resistant to H2 O2 exposure than cell-derived trypomastigotes.Those results confirm that the BER pathway and particularly the AP endonuclease activity play an important role in epimastigote and metacyclic trypomastigote oxidative DNA damage resistance leading to parasite survival and persistence inside the mammalian and insect host cells.


Assuntos
Dano ao DNA , Reparo do DNA , Estresse Oxidativo , Proteínas de Protozoários/metabolismo , Trypanosoma cruzi/enzimologia , DNA Liase (Sítios Apurínicos ou Apirimidínicos)/genética , Genes Dominantes , Humanos , Peróxido de Hidrogênio/farmacologia , Microrganismos Geneticamente Modificados , Proteínas de Protozoários/genética , Trypanosoma cruzi/genética
5.
Rev Med Chil ; 147(12): 1543-1552, 2019 Dec.
Artigo em Espanhol | MEDLINE | ID: mdl-32186618

RESUMO

Background The diagnosis of obstructive sleep apnea syndrome (OSAS) is based on nocturnal records: polysomnography or respiratory polygraphy. However, their high costs limit their use. Aim To examine the predictive value of three sleep questionnaires (STOP, STOP-Bang, Epworth Sleepiness Scale (ESS) in the screening of OSAS in Chilean adults. Material and Methods During the National Health Survey 2016/17, 205 adults aged 50.7 ± 15.0 years (46% males) living in the Metropolitan Region answered sleep questionnaires and underwent an ambulatory respiratory polygraphy. The sensitivity, specificity, positive and negative predictive values and receiver operating characteristic curves of sleep questionnaires were calculated. Results Fifty nine percent of participants had OSAS which was moderate to severe in 26%. The clinical variables associated with OSAS were age, male gender, hypertension, dyslipidemia, overweight, cervical and waist circumferences, history of regular snoring and witnessed apneas. Daytime somnolence, insomnia and unrefreshing sleep were not associated to OSAS risk. STOP, STOP-Bang and ESS questionnaires classified 64%, 71% and 12% of cases as high risk for OSAS, respectively. The STOP and STOP-Bang questionnaires had the highest sensitivity to predict OSAS (76% and 89%, respectively) while the ESS had the highest specificity (91%). Conclusions The sleep questionnaires allowed to identify the subjects at high risk for OSAS in this sample of adults from the Metropolitan Region.


Assuntos
Apneia Obstrutiva do Sono/diagnóstico , Inquéritos e Questionários , Adulto , Idoso , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Polissonografia , Curva ROC , Reprodutibilidade dos Testes , Fatores de Risco , Sensibilidade e Especificidade , População Urbana
6.
Acta Trop ; 186: 35-40, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30018029

RESUMO

Congenital Chagas disease, caused by Trypanosoma cruzi (T. cruzi), has become epidemiologically relevant. The probability of congenital transmission depends on the maternal and developing fetal/newborn immune responses, placental factors and importantly, the virulence of the parasite. It has been proposed, that different genotypes of T. cruzi and their associated pathogenicity, virulence and tissue tropism may play an important role in congenital infection. Since there is no laboratory or animal model that recapitulates the complexities of vertical transmission in humans, here we studied parasite infectivity in human placental explants (HPE) as well as in the human trophoblast-derived cell line BeWo of the Y(DTU II) and the VD (TcVI) T. cruzi strains; the latter was isolated from a human case of congenital infection. Our results show that the VD strain is more infective and pathogenic than the Y strain, as demonstrated by qPCR and cell counting as well as by histopathological analysis. The present study constitutes the first approach to study the relationship between parasite two parasite strains from different genotypes and the infection efficiency in human placenta.


Assuntos
Doença de Chagas/transmissão , Interações Hospedeiro-Parasita/fisiologia , Placenta/parasitologia , Complicações Infecciosas na Gravidez/parasitologia , Trypanosoma cruzi/fisiologia , Animais , Linhagem Celular , Doença de Chagas/congênito , Feminino , Feto , Humanos , Transmissão Vertical de Doença Infecciosa , Placenta/imunologia , Gravidez , Complicações Infecciosas na Gravidez/imunologia , Trypanosoma cruzi/citologia
7.
PLoS One ; 13(5): e0197620, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29771992

RESUMO

Cystic echinococcosis (CE), a parasitic disease caused by the cestode Echinococcus granulosus sensu lato (s.l.), is a worldwide zoonotic infection. Although endemic in Chile, information on the molecular characteristics of CE in livestock remains scarce. Therefore we aimed to describe the status of infection with E. granulosus s.l. in cattle from central Chile and also to contribute to the study of the molecular epidemiology of this parasite. According to our results, the prevalence of CE is 18.84% in cattle, similar to previous reports from Chile, suggesting that the prevalence in Santiago Metropolitan area has not changed in the last 30 years. Most of the cysts were found only in lungs (51%), followed by concurrent infection in liver and lungs (30%), and only liver (19%). Molecular characterization of the genetic diversity and population structure of E. granulosus s.l. from cattle in central Chile was performed using a section of the cytochrome c oxidase subunit 1 (cox1) mitochondrial gene. E. granulosus sensu stricto (s.s.) (G1-G3 genotypes) was confirmed by RFLP-PCR to be the dominant species affecting cattle (284 samples/290 samples); we also report for the first time in Chile the presence of E. ortleppi (G5 genotype) (2 samples/61 samples). The Chilean E. granulosus s.s. parsimony network displayed 1 main haplotype. Additional studies using isolates from many locations across Chile and different intermediate hosts will provide more data on the molecular structure of E. granulosus s.s. within this region. Likewise, investigations of the importance of E. ortleppi in human infection in Chile deserve future attention.


Assuntos
Doenças dos Bovinos/parasitologia , Equinococose/veterinária , Echinococcus/isolamento & purificação , Animais , Bovinos , Doenças dos Bovinos/epidemiologia , Chile/epidemiologia , DNA de Helmintos/análise , Equinococose/epidemiologia , Equinococose/parasitologia , Echinococcus/classificação , Echinococcus/fisiologia , Feminino , Fertilidade , Genes de Helmintos , Genes Mitocondriais , Haplótipos , Masculino , Mutação , Especificidade de Órgãos , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Prevalência , Alinhamento de Sequência
8.
J Cell Biochem ; 119(7): 5985-5995, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29575156

RESUMO

Trypanosoma cruzi, the causative agent of Chagas' disease survives to DNA damage generated by ROS/RNS inside to their different hosts. In recent eukaryotes, oxidative DNA damage is repaired mainly by the Base Excision Repair (BER) pathway, being essential the apurinic/apyrimidinic endonuclease activity. Using a pTREX-gfp vector, the nucleotide sequence that encodes T. cruzi AP endonuclease TcAP1 (orthologue of human APE1) and a putative TcAP1 dominant negative (TcAP1DN), were transfectedand expressed in T. cruzi epimastigotes. TcAP1-GFP and TcAP1DN-GFP were expressed in those modified epimastigotes and found in the parasite nucleus. The endonucleases were purified under native conditions and the AP endonuclease activity was evaluated. While TcAP1 presents the expected AP endonuclease activity TcAP1DN does not. Moreover, TcAP1DN partially inhibits in vitro TcAP1 enzymatic activity. Transfected epimastigotes expressing TcAP1-GFP and TcAP1DN-GFP were differentiated to infective trypomastigotes. The infective parasites maintained both proteins (TcAP1-GFP and TcAP1DN-GFP) in the nucleus. The overexpression of TcAP1-GFP in epimastigotes and trypomastigotes increases the viability of both parasite forms when exposed to oxidative stress while the expression of TcAP1DN-GFP did not show any in vivo inhibitory effect, suggesting that endogenous TcAP1 constitutive expression overcomes the TcAP1DN inhibitory activity. Our results show that TcAP1 is important for trypomastigote survival under oxidative conditions similar to those found in infected mammalian cells, then increasing its permanence in the infected cells and the possibility of development of Chagas disease.


Assuntos
Doença de Chagas/patologia , Dano ao DNA , DNA Liase (Sítios Apurínicos ou Apirimidínicos)/metabolismo , Estresse Oxidativo , Proteínas de Protozoários/metabolismo , Trypanosoma cruzi/crescimento & desenvolvimento , Trypanosoma cruzi/metabolismo , Sequência de Aminoácidos , Doença de Chagas/genética , Doença de Chagas/parasitologia , Reparo do DNA , DNA Liase (Sítios Apurínicos ou Apirimidínicos)/genética , Humanos , Estágios do Ciclo de Vida , Mutação , Oxirredução , Proteínas de Protozoários/genética , Homologia de Sequência , Trypanosoma cruzi/genética
9.
Infect Genet Evol ; 55: 332-342, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28970112

RESUMO

Trypanosoma cruzi is a protozoan parasite and the causative agent of Chagas disease. Like most living organisms, it is susceptible to oxidative stress, and must adapt to distinct environments. Hence, DNA repair is essential for its survival and the persistence of infection. Therefore, we studied whether T. cruzi has a homolog counterpart of the MutY enzyme (TcMYH), important in the DNA Base Excision Repair (BER) mechanism. Analysis of T. cruzi genome database showed that this parasite has a putative MutY DNA glycosylase sequence. We performed heterologous complementation assays using this genomic sequence. TcMYH complemented the Escherichia coli MutY- strain, reducing the mutation rate to a level similar to wild type. In in vitro assays, TcMYH was able to remove an adenine that was opposite to 8-oxoguanine. We have also constructed a T. cruzi lineage that overexpresses MYH. Although in standard conditions this lineage has similar growth to control cells, the overexpressor is more sensitive to hydrogen peroxide and glucose oxidase than the control, probably due to accumulation of AP sites in its DNA. Localization experiments with GFP-fused TcMYH showed this enzyme is present in both nucleus and mitochondrion. QPCR and MtOX results reinforce the presence and function of TcMYH in these two organelles. Our data suggest T. cruzi has a functional MYH DNA glycosylase, which participates in nuclear and mitochondrial DNA Base Excision Repair.


Assuntos
DNA Glicosilases/genética , DNA Glicosilases/metabolismo , Estresse Oxidativo , Trypanosoma cruzi/genética , Trypanosoma cruzi/metabolismo , Sequência de Aminoácidos , Dano ao DNA , DNA Glicosilases/química , Reparo do DNA , DNA Mitocondrial , Ativação Enzimática , Glucose Oxidase/metabolismo , Peróxido de Hidrogênio/metabolismo , Mutação , Transporte Proteico , Análise de Sequência de DNA
11.
Eur J Pharmacol ; 799: 41-47, 2017 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-28132911

RESUMO

Leukotriene A4 hydrolase is a soluble enzyme with epoxide hydrolase and aminopeptidase activities catalysing the conversion of leukotriene A4 to leukotriene B4 and the hydrolysis of the peptide proline-glycine-proline. Imbalances in leukotriene B4 synthesis are related to several pathologic conditions. Currently there are no available drugs capable to modulate the synthesis of leukotriene B4 or to block its receptors. Here we show the inhibitory profile of alpha lipoic acid on the activity of leukotriene A4 Hydrolase. Alpha lipoic acid inhibited both activities of the enzyme at concentrations lower than 10µM. The 5-lipoxygenase inhibitor zileuton, or the 5-lipoxygenase activating protein inhibitor MK-886, were unable to inhibit the activity of the enzyme. Acute promyelocytic leukaemia HL-60 cells were differentiated to leukotriene A4 hydrolase expressing neutrophil-like cells. Alpha lipoic acid inhibited the aminopeptidase activity of the cytosolic fraction from neutrophil-like cells but had no effect on the cytosolic fraction from undifferentiated cells. Docking and molecular dynamic approximations revealed that alpha lipoic acid participates in electrostatic interactions with K-565 and R-563, which are key residues for the carboxylate group recognition of endogenous substrates by the enzyme. Alpha lipoic acid is a compound widely used in clinical practice, most of its therapeutic effects are associated with its antioxidants properties, however, antioxidant effect alone is unable to explain all clinical effects observed with alpha lipoic acid. Our results invite to evaluate the significance of the inhibitory effect of alpha lipoic acid on the catalytic activity of leukotriene A4 hydrolase using in vivo models.


Assuntos
Inibidores Enzimáticos/farmacologia , Epóxido Hidrolases/metabolismo , Ácido Tióctico/farmacologia , Citosol/enzimologia , Relação Dose-Resposta a Droga , Epóxido Hidrolases/antagonistas & inibidores , Humanos , Neutrófilos/citologia
12.
J Cell Biochem ; 118(7): 1722-1732, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-27935092

RESUMO

FLAP endonucleases (FEN) are involved both in DNA replication and repair by processing DNA intermediaries presenting a nucleotide flap using its phosphodiesterase activity. In spite of these important functions in DNA metabolism, this enzyme was not yet studied in Trypanosomatids. Trypanosoma cruzi, the ethiological agent of Chagas disease, presents two dividing cellular forms (epimastigote and amastigote) and one non-proliferative, infective form (trypomastigote). The parasite survives DNA damage produced by reactive species generated in its hosts. The activity of a T. cruzi FLAP endonuclease (TcFEN1) was determined in the three cellular forms of the parasite using a DNA substrate generated by annealing three different oligonucleotides to form a double-stranded DNA with a 5' flap in the middle. This activity showed optimal pH and temperature similar to other known FENs. The substrate cut by the flap endonuclease activity could be ligated by the parasite generating a repaired DNA product. A DNA flap endonuclease coding sequence found in the T. cruzi genome (TcFEN1) was cloned, inserted in parasite expression vectors and transfected to epimastigotes. The purified native recombinant protein showed DNA flap endonuclease activity. This endonuclease was found located in the parasite nucleus of transfected epimastigotes and its over-expression increased both parasite proliferation and survival to H2 O2 . The presence of a flap endonuclease activity in T. cruzi and its nuclear location are indicative of the participation of this enzyme in DNA processing of flap fragments during DNA replication and repair in this parasite of ancient evolutive origin. J. Cell. Biochem. 118: 1722-1732, 2017. © 2016 Wiley Periodicals, Inc.


Assuntos
Endonucleases Flap/metabolismo , Proteínas de Protozoários/metabolismo , Trypanosoma cruzi/enzimologia , Trypanosoma cruzi/metabolismo , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Biologia Computacional , Reparo do DNA/efeitos dos fármacos , Reparo do DNA/genética , Endonucleases Flap/genética , Peróxido de Hidrogênio/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Proteínas de Protozoários/genética , Trypanosoma cruzi/efeitos dos fármacos , Trypanosoma cruzi/genética
13.
J Infect Chemother ; 22(8): 526-31, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27262751

RESUMO

OBJECTIVE: To determine the prevalence of nontuberculous mycobacteria (NTM) colonization and disease in cystic fibrosis (CF) patients. PATIENTS AND METHODS: All the CF patients followed-up from 2002 to 2012 with three acid-fast bacilli (AFB) cultures were included. The American Thoracic Society (ATS) criteria for NTM lung disease were applied. RESULTS: Forty-four of the 53 patients being followed-up were included. The mean time of follow-up was 7.0 years. A total of 18 patients (40.9%) were NTM positive. The NTN mean annual prevalence was 14.1%. The risk of Mycobacterium abscessus complex was higher in the group of 10-14 years-old (p < 0.001). Ten patients (22.7% of the entire cohort) met the ATS microbiological criteria. The mean annual prevalence of NTM disease was 10.4%. Seven patients (four with Mycobacterium simiae and three with M. abscessus complex) with multiple positive cultures, positive AFB smears and clinical worsening were treated. Three patients with M. simiae and none of those with M. abscessus were cured. CONCLUSIONS: Overall NTM prevalence of colonization and disease were high in our CF patients. Patients <15 years old had a higher risk of M. abscessus complex colonization. Multiple positive cultures or positive AFB smears were associated with disease.


Assuntos
Fibrose Cística/microbiologia , Infecções por Mycobacterium não Tuberculosas/epidemiologia , Infecções por Mycobacterium não Tuberculosas/microbiologia , Micobactérias não Tuberculosas/isolamento & purificação , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Pulmão/microbiologia , Masculino , Pessoa de Meia-Idade , Prevalência , Adulto Jovem
14.
PLoS One ; 11(6): e0157270, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27284968

RESUMO

Trypanosoma cruzi, the etiological agent of Chagas' disease, presents three cellular forms (trypomastigotes, epimastigotes and amastigotes), all of which are submitted to oxidative species in its hosts. However, T. cruzi is able to resist oxidative stress suggesting a high efficiency of its DNA repair machinery.The Base Excision Repair (BER) pathway is one of the main DNA repair mechanisms in other eukaryotes and in T. cruzi as well. DNA glycosylases are enzymes involved in the recognition of oxidative DNA damage and in the removal of oxidized bases, constituting the first step of the BER pathway. Here, we describe the presence and activity of TcNTH1, a nuclear T. cruzi DNA glycosylase. Surprisingly, purified recombinant TcNTH1 does not remove the thymine glycol base, but catalyzes the cleavage of a probe showing an AP site. The same activity was found in epimastigote and trypomastigote homogenates suggesting that the BER pathway is not involved in thymine glycol DNA repair. TcNTH1 DNA-binding properties assayed in silico are in agreement with the absence of a thymine glycol removing function of that parasite enzyme. Over expression of TcNTH1 decrease parasite viability when transfected epimastigotes are submitted to a sustained production of H2O2.Therefore, TcNTH1 is the only known NTH1 orthologous unable to eliminate thymine glycol derivatives but that recognizes and cuts an AP site, most probably by a beta-elimination mechanism. We cannot discard that TcNTH1 presents DNA glycosylase activity on other DNA base lesions. Accordingly, a different DNA repair mechanism should be expected leading to eliminate thymine glycol from oxidized parasite DNA. Furthermore, TcNTH1 may play a role in the AP site recognition and processing.


Assuntos
Doença de Chagas/parasitologia , DNA Glicosilases/metabolismo , Trypanosoma cruzi/enzimologia , Trypanosoma cruzi/fisiologia , Sequência de Aminoácidos , Animais , Linhagem Celular , Dano ao DNA , DNA Glicosilases/química , DNA Glicosilases/genética , Reparo do DNA , Regulação da Expressão Gênica , Humanos , Modelos Moleculares , Estresse Oxidativo , Conformação Proteica , Ratos , Alinhamento de Sequência , Timina/análogos & derivados , Timina/metabolismo , Trypanosoma cruzi/química , Trypanosoma cruzi/genética
15.
Bol. Hosp. Viña del Mar ; 71(2): 61-66, abr.2015. tab, graf
Artigo em Espanhol | LILACS | ID: lil-779164

RESUMO

El artículo presenta una caracterización del consumo de tabaco en Chile, utilizando para ello el modelo ecológico de enfermedades transmisibles, analizándolo como enfermedad crónica de carácter epidémica. Se comentan características del hospedero, agente etiológico, reservorio, ambiente y vector, en relación al tabaco. El consumo de cigarrillo evoluciona rápidamente en sociedades desarrolladas hacia bajas prevalencias en actuales. Globalmente la situación es heterogénea, persistiendo países como Chile, con consumo elevado y de difícil control. La prevalencia de fumadores actuales es de 40,6 por ciento, estimándose que un tercio de ellos podrían ser dependientes a la nicotina. En base al modelo de progresión de la epidemia de tabaquismo (López et al), se postula que Chile se encuentra en la Etapa III de la epidemia, caracterizada por alto consumo de tabaco en varones, prevalencia aun en aumento en mujeres e incipiente manifestación de carga de enfermedad atribuible al tabaco. Chile ha modificado recientemente su legislación sobre tabaco (venta y publicidad, preservación de aire libre de humo de tabaco, restricción al consumo y aumento de impuestos), lo que augura mejores perspectivas de control. El modelo de progresión epidémica muestra buena capacidad predictiva, sugiriendo para Chile para las próximas décadas, aumento en enfermedades atribuibles al tabaco (cardiovasculares, respiratorias crónicas y tumores malignos), superado el umbral de tiempo de exposición a prevalencias elevadas. A través de este análisis se identifican oportunidades de intervención tanto a nivel clínico como de salud pública, y se sugieren medidas específicas para optimizar el control y tratamiento del tabaquismo en nuestro país...


An epidemiological description about tobacco consumption in Chile is introduced in this article, based on the ecological model about transmission derived from communicable diseases. The logic of epidemic diseases and epidemiologic triad is translated and applied to the case of tobacco consumption looking for main characteristics of etiological agent (tobacco products), host, environment, main vector and their reservoir. Global trends on smoking behavior has been rapidly changed from high rates to unexpected low rates in developed world, reached due to successful strategies on prevention and control. Chile shows a complex profile, with high rates of smoking in general population, among adolescents and young adults and women. The tobacco epidemic progression model (Lopez et al 1994) is analyzed in order to understand its timing, changes in smoking prevalence and the burden of tobacco attributable burden of diseases. Chile is probably placed in an early stage of phase III of the proposed epidemic model on tobacco consumption, facing the next decades, raising trends in mortality rates due to chronic cardiovascular and respiratory diseases and malignant tumors, after the threshold of minimal time exposure time has been surpassed. Crucial support coming from health and teaching professional is expecting for better Chilean policies on prevention, control and treatment of smoking...


Assuntos
Humanos , Fumar/efeitos adversos , Fumar/epidemiologia , Chile/epidemiologia , Fumar/prevenção & controle
16.
Parasitology ; 141(5): 682-96, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24476762

RESUMO

Chagas disease, endemic in 21 countries across Latin America, kills more people in the region each year than any other parasite-borne disease. Therapeutic options have problems ranging from toxicity, poor efficacy, drug resistance and high cost. Thus, cheaper and less toxic treatments are necessary. From our in-house chemical library of agents against Trypanosoma cruzi the most relevant N-oxide-containing heterocycles were selected for mode of action and type of death studies. Also included in these studies were two active nitrofuranes. Epimastigotes of T. cruzi were used as the biological model in this study. The metabolic profile was studied by 1H NMR in association with the MTT assay. Excreted catabolites data, using 1H NMR spectroscopy, showed that most of the studied N-oxides were capable of decreasing both the release of succinate and acetate shedding, the compounds therefore possibly acting on mitochondria. Only quinoxalines and the nitrofurane Nf1 showed significant mitochondrial dehydrogenase inhibitions, but with different dose-time profiles. In the particular case of quinoxaline Qx2 the glucose uptake study revealed that the integrity of some pathways into the glycosome could be affected. Optic, fluorescence (TUNEL and propidium iodide) and transmission electron microscopy (TEM) were employed for type of death studies. These studies were complemented with 1H NMR to visualize mobile lipids. At low concentrations none of the selected compounds showed a positive TUNEL assay. However, both quinoxalines, one furoxan and one benzofuroxan showed a necrotic effect at high concentrations. Curiously, one furoxan, Fx1, one benzofuroxan, Bfx1, and one nitrofurane, Nf1, caused a particular phenotype, with a big cytoplasmatic vacuole being observed while the parasite was still alive. Studies of TEM and employing a protease inhibitor (3-methyladenine) suggested an autophagic phenotype for Bfx1 and Nf1 and a 'BigEye' phenotype for Fx1.


Assuntos
Doença de Chagas/parasitologia , Óxidos N-Cíclicos/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Óxidos N-Cíclicos/química , Humanos , Microscopia Eletrônica de Transmissão , Necrose , Fenótipo , Tripanossomicidas/química , Trypanosoma cruzi/fisiologia , Trypanosoma cruzi/ultraestrutura
17.
Exp Parasitol ; 133(1): 12-7, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23116598

RESUMO

Chagas' disease is caused by the haemophlagelated protozoan Trypanosoma cruzi (T. cruzi). During congenital transmission the parasite breaks down the placental barrier, however studies about the physiopathology of this process are scarce. Different signal transduction pathways are involved during cell invasion of the parasite. However, the possible role of those processes during tissue infection has not been studied. In the present study we analyzed the modulation of two signal transduction pathways, PLC-γ and ERK1/2 MAPK, during ex vivo infection of human placental chorionic villi explants. Chorionic villi from healthy woman placentas were incubated in the presence or absence of 10(5) or 10(6)T. cruzi trypomastigotes (DM28c strain) with or without specific inhibitors for each pathway. Effective infection was tested determining parasite DNA by PCR. The activation of PLC-γ and ERK1/2 MAPK signaling pathways was determined by western blotting and immunofluorescence. The low concentration of T. cruzi trypomastigotes activates both signaling pathways; however, the high concentration of parasite induces a modest activation of the PLC-γ pathway and impairs the ERK1/2 MAPK pathway activation. Interestingly, inhibition of any of those signaling pathways did not prevent parasite infection, as it was previously shown in cell cultures. We conclude that both signal transduction pathways are modulated during ex vivo T. cruzi infection of human placental chorionic villi explants.


Assuntos
Sistema de Sinalização das MAP Quinases/fisiologia , Fosfolipase C gama/metabolismo , Placenta/enzimologia , Placenta/parasitologia , Animais , Chlorocebus aethiops , Vilosidades Coriônicas/enzimologia , Vilosidades Coriônicas/parasitologia , Feminino , Humanos , Gravidez , Transdução de Sinais/fisiologia , Células Vero
18.
Mol Immunol ; 52(3-4): 133-40, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22673211

RESUMO

In Latin America, there are about 10-12 million people infected with Trypanosoma cruzi, the agent of Chagas' disease, one of the most important neglected tropical parasitism. Identification of molecular targets, specific for the aggressor or host cells or both, may be useful in the development of pharmacological and/or immunological therapeutic tools. Classic efforts in Chagas' disease explore those strategies. Although the immune system frequently controls parasite aggressions, sterile immunity is seldom achieved and chronic interactions are thus established. However, laboratory-modified immunologic probes aimed at selected parasite targets, may be more effective than their unmodified counterparts. Calreticulin (CRT) from vertebrates is a calcium binding protein, present mainly in the endoplasmic reticulum (ER), where it directs the conformation of proteins and controls calcium levels. We have isolated, gene-cloned, expressed and characterized T. cruzi calreticulin (TcCRT). Upon infection, the parasite can translocate this molecule from the ER to the surface, where it inhibits both the classical and lectin complement pathways. Moreover, by virtue of its capacity to bind and inactivate first complement component C1, it promotes parasite infectivity. These two related properties reside in the central domain of this molecule. A different domain, amino terminal, binds to endothelial cells, thus inhibiting their angiogenic capacity. Since tumor growth depends, to a large extent on angiogenesis, their growth is also inhibited.


Assuntos
Calreticulina/metabolismo , Doença de Chagas/imunologia , Doença de Chagas/parasitologia , Interações Hospedeiro-Parasita , Neoplasias/patologia , Trypanosoma cruzi/fisiologia , Inibidores da Angiogênese , Animais , Proliferação de Células , Doença de Chagas/patologia , Humanos , Neoplasias/metabolismo , Trypanosoma cruzi/imunologia , Trypanosoma cruzi/patogenicidade
19.
Parasitology ; 139(4): 506-15, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22216891

RESUMO

Cell death mechanisms in Trypanosoma cruzi have not been disclosed in detail though different conventional techniques have been used in the classification of parasite-cell death type. Nuclear magnetic resonance (NMR) has successfully been used as a tool to evaluate the onset of apoptosis in a number of higher eukaryote-cell models analysing the ratio of CH(2)/CH(3) integration from the visible mobile lipids (VML). Surprisingly, this versatile non-invasive spectroscopy technique has never been employed with this purpose in T. cruzi. In the present study it is shown that under different parasite death-conditions the ratio CH(2)/CH(3) varied drastically. Thus, T. cruzi epimastigotes in apoptotic conditions increase significantly this ratio while in necrotic as well as in autophagic situations the parasites maintain the VML, CH(2)/CH(3) ratio, in normal values. Additionally, other VML markers commonly used in these studies, such as the change in the region of methyl-choline moiety, -N(+)(CH(3))(3), exhibited different particular patterns according to the type of cell death. Our results suggest that the (1)H NMR-VML technique is an adequate tool to discriminate different T. cruzi death pathways.


Assuntos
Morte Celular , Lipídeos/análise , Espectroscopia de Ressonância Magnética/métodos , Trypanosoma cruzi/crescimento & desenvolvimento , Animais , Apoptose/fisiologia , Autofagia , Colina/análise , Colina/metabolismo , Peróxido de Hidrogênio/farmacologia , Necrose , Nifurtimox/farmacologia , Trypanosoma cruzi/efeitos dos fármacos
20.
J Trop Med ; 2012: 758357, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22007243

RESUMO

Chagas disease, produced by the protozoan Trypanosoma cruzi (T. cruzi), is one of the most frequent endemic diseases in Latin America. In spite the fact that in the past few years T. cruzi congenital transmission has become of epidemiological importance, studies about this mechanism of infection are scarce. In order to explore some morphological aspects of this infection in the placenta, we analyzed placentas from T. cruzi-infected mothers by immunohistochemical and histochemical methods. Infection in mothers, newborns, and placentas was confirmed by PCR and by immunofluorescence in the placenta. T. cruzi-infected placentas present destruction of the syncytiotrophoblast and villous stroma, selective disorganization of the basal lamina, and disorganization of collagen I in villous stroma. Our results suggest that the parasite induces reorganization of this tissue component and in this way may regulate both inflammatory and immune responses in the host. Changes in the ECM of placental tissues, together with the immunological status of mother and fetus, and parasite load may determine the probability of congenital transmission of T. cruzi.

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