RESUMEN
While persistent infection with oncogenic types of human Papillomavirus (HPV) is required for cervical epithelial cell transformation and cervical carcinogenesis, HPV infection alone is not sufficient to induce tumorigenesis. Only a minor fraction of HPV infections produce high-grade lesions and cervical cancer, suggesting complex host-virus interactions. Based on its pronounced immunoinhibitory properties, human leukocyte antigen (HLA)-G has been proposed as a possible prognostic biomarker and therapeutic target relevant in a wide variety of cancers and viral infections, but to date remains underexplored in cervical cancer. Given the possible influence of HLA-G on the clinical course of HPV infection, cervical lesions and cancer progression, a better understanding of HLA-G involvement in cervical carcinogenesis might contribute to two aspects of fundamental importance: 1. Characterization of a novel diagnostic/prognostic biomarker to identify cervical cancer and to monitor disease stage, critical for patient screening; 2. Identification of HLA-G-driven immune mechanisms involved in lesion development and cancer progression, leading to the development of strategies for modulating HLA-G expression for treatment purposes. Thus, this systematic review explores the potential involvement of HLA-G protein expression and polymorphisms in cervical carcinogenesis.
Asunto(s)
Antígenos HLA-G/fisiología , Neoplasias del Cuello Uterino/inmunología , Femenino , Antígenos HLA-G/genética , Humanos , Polimorfismo Genético , Pronóstico , Neoplasias del Cuello Uterino/etiología , Neoplasias del Cuello Uterino/terapiaRESUMEN
Sexually transmitted diseases (STDs) are caused by several pathogens, including bacteria, viruses and protozoa, and can induce male infertility through multiple pathophysiological mechanisms. Additionally, horizontal transmission of STD pathogens to sexual partners or vertical transmission to fetuses and neonates is possible. Chlamydia trachomatis, Ureaplasma spp., human papillomavirus, hepatitis B and hepatitis C viruses, HIV-1 and human cytomegalovirus have all been detected in semen from symptomatic and asymptomatic men with testicular, accessory gland and urethral infections. These pathogens are associated with poor sperm quality and decreased sperm concentration and motility. However, the effects of these STD agents on semen quality are unclear, as are the effects of herpes simplex virus type 1 and type 2, Neisseria gonorrhoeae, Mycoplasma spp., Treponema pallidum and Trichomonas vaginalis, because few studies have evaluated the influence of these pathogens on male infertility. Chronic or inadequately treated infections seem to be more relevant to infertility than acute infections are, although in many cases the exact aetiological agents remain unknown.
Asunto(s)
Infertilidad Masculina , Semen/microbiología , Semen/parasitología , Enfermedades de Transmisión Sexual/complicaciones , Chlamydia trachomatis , Citomegalovirus , VIH , Hepacivirus , Virus de la Hepatitis B , Humanos , Infertilidad Masculina/microbiología , Infertilidad Masculina/parasitología , Masculino , Mycoplasma , Neisseria gonorrhoeae , Papillomaviridae , Semen/virología , Análisis de Semen , Enfermedades de Transmisión Sexual/microbiología , Enfermedades de Transmisión Sexual/parasitología , Enfermedades de Transmisión Sexual/transmisión , Simplexvirus , Treponema pallidum , Trichomonas vaginalis , UreaplasmaRESUMEN
Sexually transmitted diseases (STDs) may impair sperm parameters and functions thereby promoting male infertility. To date limited molecular studies were conducted to evaluate the frequency and type of such infections in semen Thus, we aimed at conceiving and validating a multiplex PCR (M-PCR) assay for the simultaneous detection of the following STD pathogens in semen: Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, Trichomonas vaginalis, Herpes virus simplex (HSV) -1 and -2, and Treponema pallidum; We also investigated the potential usefulness of this M-PCR assay in screening programs for semen pathogens. In addition, we aimed: to detect human Papillomavirus (HPV) and genotypes by single PCR (sPCR) in the same semen samples; to determine the prevalence of the seven STDs, HPV and co-infections; to assess the possibility that these infections affect semen parameters and thus fertility. The overall validation parameters of M-PCR were extremely high including agreement (99.2%), sensitivity (100.00%), specificity (99.70%), positive (96.40%) and negative predictive values (100.00%) and accuracy (99.80%). The prevalence of STDs was very high (55.3%). Furthermore, associations were observed between STDs and changes in semen parameters, highlighting the importance of STD detection in semen. Thus, this M-PCR assay has great potential for application in semen screening programs for pathogens in infertility and STD clinics and in sperm banks.
Asunto(s)
Reacción en Cadena de la Polimerasa Multiplex/métodos , Semen/microbiología , Enfermedades de Transmisión Sexual/diagnóstico , Adulto , Alphapapillomavirus/aislamiento & purificación , Chlamydia trachomatis/aislamiento & purificación , Humanos , Masculino , Persona de Mediana Edad , Mycoplasma genitalium/aislamiento & purificación , Neisseria gonorrhoeae/aislamiento & purificación , Semen/virología , Sensibilidad y Especificidad , Enfermedades de Transmisión Sexual/microbiología , Enfermedades de Transmisión Sexual/virología , Simplexvirus/aislamiento & purificación , Treponema/aislamiento & purificaciónRESUMEN
We determined the prevalence of seven clinically important pathogens that cause sexually transmitted infections (STIs) (Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, Trichomonas vaginalis, herpes simplex virus 1 [HSV-1], HSV-2, and Treponema pallidum), by using a multiplex polymerase chain reaction (M-PCR) in samples from Brazilian woman infected with human immunodeficiency virus 1 (HIV-1) and uninfected Brazilian women (controls). The M-PCR assay identified all STIs tested for and surprisingly, occurred association between the control and STIs. This association was probably caused by excellent HIV infection control and regular monitoring in these women established by public health strategies in Brazil to combat HIV/acquired immunodeficiency syndrome. Studies using this M-PCR in different populations may help to better elucidate the roles of STIs in several conditions.
Asunto(s)
Infecciones por VIH/epidemiología , Reacción en Cadena de la Polimerasa Multiplex/métodos , Enfermedades de Transmisión Sexual/diagnóstico , Adulto , Brasil/epidemiología , Chlamydia trachomatis/genética , Chlamydia trachomatis/aislamiento & purificación , Cartilla de ADN/genética , Femenino , Infecciones por VIH/complicaciones , Herpesvirus Humano 1/genética , Herpesvirus Humano 1/aislamiento & purificación , Herpesvirus Humano 2/genética , Herpesvirus Humano 2/aislamiento & purificación , Humanos , Persona de Mediana Edad , Mycoplasma genitalium/genética , Mycoplasma genitalium/aislamiento & purificación , Neisseria gonorrhoeae/genética , Neisseria gonorrhoeae/aislamiento & purificación , Prevalencia , Enfermedades de Transmisión Sexual/epidemiología , Treponema pallidum/genética , Treponema pallidum/aislamiento & purificación , Trichomonas vaginalis/genética , Trichomonas vaginalis/aislamiento & purificaciónRESUMEN
BACKGROUND: Human Papillomavirus (HPV) infection is a serious problem for human immunodeficiency virus (HIV)-infected women, increases their risk of cervical lesions and cancer. In cervical carcinogenesis, mutations in the p53 gene occur most frequently within exons 5-8. To our knowledge, no previous studies have analyzed mutations in exons 5-8 of the p53 gene in HIV- and HPV-infected women. In our study, we verified these mutations in women with and without cervical abnormalities. FINDINGS: The study included 160 women, divided into three groups: (1) 83 HPV- and HIV-infected women (HIV group); (2) 37 HPV-infected/HIV-uninfected (control group); and (3) 40 normal cytology/DNA-HPV negative/HIV-uninfected women (negative control p53 reactions). HPV-DNA was detected using polymerase chain reaction (PCR) and genotyping by PCR-restriction fragment length polymorphism analysis. Using primers for exons 5-8, the mutation of the p53 gene was verified by PCR-single strand conformational polymorphism. The total mutation of the p53 gene in exons 5-8 was not significantly associated with the HIV and control groups. The mutations in exon 7 were the highest in the HIV group (43.8%) and in exon 6 in the control group (57.2%) (p = 0.0793) suggesting a tendency toward differential mutation in exon 7 in the HIV group. CONCLUSIONS: Our study provides preliminary evidence that the mutation in exon 7 might be an important differentiating factor for cervical carcinogenesis in HIV-infected women. This aspect deserves an additional cross-sectional and longitudinal study using a larger sample size with a higher number of High-grade squamous intraephitelial lesion (HSIL) to observe the evolution of cervical lesions.
RESUMEN
Nitric oxide-derived oxidants such as nitrogen dioxide and peroxynitrite have been receiving increasing attention as mediators of nitric oxide toxicity. Indeed, nitrated and nitrosated compounds have been detected in biological fluids and tissues of healthy subjects and in higher yields in patients under inflammatory or infectious conditions as a consequence of nitric oxide overproduction. Among them, nitrated lipids have been detected in vivo. Here, we confirmed and extended previous studies by demonstrating that nitrolinoleate, chlolesteryl nitrolinoleate, and nitrohydroxylinoleate induce vasorelaxation in a concentration-dependent manner while releasing nitric oxide that was characterized by chemiluminescence-and EPR-based methodologies. As we first show here, diffusible nitric oxide production is likely to occur by isomerization of the nitrated lipids to the corresponding nitrite derivatives that decay through homolysis and/or metal ion/ascorbate-assisted reduction. The homolytic mechanism was supported by EPR spin-trapping studies with 3,5-dibromo-4-nitrosobenzenesulfonic acid that trapped a lipid-derived radical during nitrolinoleate decomposition. In addition to provide a mechanism to explain nitric oxide production from nitrated lipids, the results support their role as endogenous sources of nitric oxide that may play a role in endothelium-independent vasorelaxation.
Asunto(s)
Aorta Torácica/efectos de los fármacos , Ésteres del Colesterol/farmacología , Radicales Libres/química , Ácidos Linoleicos/farmacología , Óxido Nítrico/química , Nitrocompuestos/farmacología , Vasodilatación/efectos de los fármacos , Animales , Ácido Ascórbico/farmacología , Espectroscopía de Resonancia por Spin del Electrón , Peroxidación de Lípido , Mediciones Luminiscentes , Masculino , Ratas , Ratas WistarRESUMEN
Xanthine oxidase is generally recognized as a key enzyme in purine catabolism, but its structural complexity, low substrate specificity, and specialized tissue distribution suggest other functions that remain to be fully identified. The potential of xanthine oxidase to generate superoxide radical anion, hydrogen peroxide, and peroxynitrite has been extensively explored in pathophysiological contexts. Here we demonstrate that xanthine oxidase turnover at physiological pH produces a strong one-electron oxidant, the carbonate radical anion. The radical was shown to be produced from acetaldehyde oxidation by xanthine oxidase in the presence of catalase and bicarbonate on the basis of several lines of evidence such as oxidation of both dihydrorhodamine 123 and 5,5-dimethyl-1-pyrroline-N-oxide and chemiluminescence and isotope labeling/mass spectrometry studies. In the case of xanthine oxidase acting upon xanthine and hypoxanthine as substrates, carbonate radical anion production was also evidenced by the oxidation of 5,5-dimethyl-1-pyrroline-N-oxide and of dihydrorhodamine 123 in the presence of uricase. The results indicated that Fenton chemistry occurring in the bulk solution is not necessary for carbonate radical anion production. Under the conditions employed, the radical was likely to be produced at the enzyme active site by reduction of a peroxymonocarbonate intermediate whose formation and reduction is facilitated by the many xanthine oxidase redox centers. In addition to indicating that the carbonate radical anion may be an important mediator of the pathophysiological effects of xanthine oxidase, the results emphasize the potential of the bicarbonate-carbon dioxide pair as a source of biological oxidants.
Asunto(s)
Bicarbonatos/metabolismo , Xantina Oxidasa/metabolismo , Animales , Carbonatos/metabolismo , Dominio Catalítico , Bovinos , Óxidos N-Cíclicos , Espectroscopía de Resonancia por Spin del Electrón , Radicales Libres/metabolismo , Concentración de Iones de Hidrógeno , Técnicas In Vitro , Modelos Biológicos , Oxidación-Reducción , Rodaminas , Marcadores de Spin , Especificidad por Sustrato , Xantina Oxidasa/químicaRESUMEN
Despite the importance of protein radicals in cell homeostasis and cell injury, their formation, localization, and propagation reactions remain obscure, mainly because of the difficulties in detecting and characterizing radicals, in general, and protein radicals, in particular. New approaches based on spin trapping coupled with other methodologies are under development/testing but so far they have been applied mainly to the study of protein-tyrosyl and protein-tryptophanyl radicals. Here, our aim is to emphasize the importance of developing new methodologies for the detection of glutathyil and protein-cysteinyl radicals under physiological conditions. To this end, we summarize current EPR evidence supporting the view that glutathione and protein-cysteines are among the preferential targets of nitric oxide-derived oxidants and that they are oxidized to the glutathiyl and protein-cysteinyl radicals, respectively. The possible intermediacy of these species in the biological formation of mediators of protein-cysteine redox signaling, such as S-nitrosothiols and sulfenic acids, is also discussed.
Asunto(s)
Glutatión/análisis , Óxido Nítrico/química , Proteínas/análisis , Detección de Spin , Animales , Óxidos N-Cíclicos , Espectroscopía de Resonancia por Spin del Electrón , Radicales Libres/química , Radicales Libres/metabolismo , Humanos , Oxidantes/metabolismo , Marcadores de Spin , Tirosina/químicaRESUMEN
The peroxidase activity of Cu,Zn-superoxide dismutase (Cu,Zn-SOD) has been extensively studied in recent years due to its potential relationship to familial amyotrophic lateral sclerosis. The mechanism by which Cu,Zn-SOD/hydrogen peroxide/bicarbonate is able to oxidize substrates has been proposed to be dependent on an oxidant whose nature, diffusible carbonate radical anion or enzyme-bound peroxycarbonate, remains debatable. One possibility to distinguish these species is to examine whether protein targets are oxidized to protein radicals. Here, we used EPR methodologies to study bovine serum albumin (BSA) oxidation by Cu,Zn-SOD/hydrogen peroxide in the absence and presence of bicarbonate or nitrite. The results showed that BSA oxidation in the presence of bicarbonate or nitrite at pH 7.4 produced mainly solvent-exposed and -unexposed BSA-tyrosyl radicals, respectively. Production of the latter was shown to be preceded by BSA-cysteinyl radical formation. The results also showed that hydrogen peroxide/bicarbonate extensively oxidized BSA-cysteine to the corresponding sulfenic acid even in the absence of Cu,Zn-SOD. Thus, our studies support the idea that peroxycarbonate acts as a two-electron oxidant and may be an important biological mediator. Overall, the results prove the diffusible and radical nature of the oxidants produced during the peroxidase activity of Cu,Zn-SOD in the presence of bicarbonate or nitrite.
Asunto(s)
Bicarbonatos/química , Cisteína/química , Radicales Libres/química , Nitritos/química , Peroxidasa/química , Albúmina Sérica Bovina/química , Solventes/química , Superóxido Dismutasa/química , Tirosina/química , Antioxidantes/química , Difusión , Espectroscopía de Resonancia por Spin del Electrón , Transporte de Electrón , Cinética , Oxidantes/química , Oxidación-Reducción , Detección de Spin , Compuestos de Sulfhidrilo/químicaRESUMEN
Tempol is a stable nitroxide radical that has been shown to protect laboratory animals from the injury associated with conditions of oxidative and nitrosoactive stress. Tempol's protective mechanisms against reactive oxygen species have been extensively studied, but its interactions with reactive nitrogen species remain little explored. Recently, it has been shown that tempol is a potent inhibitor of peroxynitrite-mediated phenol nitration while it increases phenol nitrosation by a complex mechanism [Carrol et al. (2000) Chem. Res. Toxicol. 13, 294]. To obtain further mechanistic insights, we reexamined the interaction of peroxynitrite with tempol in the absence and presence of carbon dioxide. Stopped-flow kinetic studies confirmed that tempol does not react directly with peroxynitrite but levels off the amount of oxygen (monitored with an oxygen electrode) and nitrite (monitored by chemiluminescence) produced from peroxynitrite in the presence and absence of carbon dioxide to about 30% and 70% of the initial oxidant concentration at pH 5.4, 6.4, and 7.4. Tempol inhibited phenol nitration while increasing the amounts of 4-nitrosophenol, that attained yields close to 30% of the peroxynitrite in the presence of carbon dioxide at pH 7.4. Fast-flow EPR experiments showed detectable changes in the instantaneous tempol concentration (maximum of 15%) only in the presence of carbon dioxide. Under these conditions, the instantaneous concentration of the carbonate radical anion was reduced by tempol in a concentration-dependent manner. The results indicate that tempol is oxidized by peroxynitrite-derived radicals (*OH and CO(3)(*-), in the absence and presence of carbon dioxide, respectively) to the oxoammonium cation which, in turn, is reduced back to tempol while oxidizing peroxynitrite to oxygen and nitric oxide. The latter reacts rapidly with peroxynitrite-derived nitrogen dioxide to produce the nitrosating species, dinitrogen trioxide. Overall, the results support a role for peroxynitrite and its derived radicals in the tissue pathology associated with inflammatory conditions.
Asunto(s)
Antioxidantes/química , Óxidos N-Cíclicos/química , Nitratos/química , Nitrocompuestos/química , Compuestos Nitrosos/química , Dióxido de Carbono/química , Espectroscopía de Resonancia por Spin del Electrón , Oxidación-Reducción , Marcadores de SpinRESUMEN
Nitrogen dioxide and carbonate radical anion have received sporadic attention thus far from biological investigators. However, accumulating data on the biochemical reactions of nitric oxide and its derived oxidants suggest that these radicals may play a role in various pathophysiological processes. These potential roles are also indicated by recent studies on the high efficiency of urate and nitroxides in protecting cells and whole animals against the injury associated with conditions of excessive nitric oxide production. The high protective effects of these antioxidants are incompletely defined at the mechanistic level but some of them can be explained by their efficiency in scavenging peroxynitrite-derived radicals, particularly nitrogen dioxide and carbonate radical anion. In this review, we provide a framework for this hypothesis and discuss the potential sources and properties of these radicals that are likely to become increasingly recognized as important mediators of biological processes.