RESUMEN
Epithelioid glioblastoma (eGB), a very aggressive and rare brain tumour, is associated with a dismal median overall survival. Effective therapies for patients with eGB, particularly with leptomeningeal dissemination, are still lacking. Here, we describe a case of a 25-year-old male diagnosed with an intramedullary cervical tumour with subsequent leptomeningeal disease. Histopathology identified a highly necrotising, epithelioid-type tumour with high cell density, most compatible with the diagnosis of an eGB. DNA analysis revealed an unprecedented B-Raf protooncogene, serine/threonine kinase (BRAF) gene variant in exon 15 (ENST00000288602.6, c.1799_1810delinsATG, p.(V600_W604delinsDG)), triggering activation of the mitogen-activated protein kinase (MAPK) pathway. Consequently, we initiated MAPK inhibitor (MAPKi) therapy, utilizing a combination of BRAF and mitogen-activated protein kinase kinase (MEK) inhibitors. Liquid chromatography-tandem mass spectrometry analysis confirmed the drugs' presence in the patient's cerebrospinal fluid, indicating their capacity to cross the blood-brain barrier. Remarkably, the patient responded very well to therapy and transitioned from a near-comatose state to significantly improved health, sustained for over three months. This study highlights that MAPKi, particularly targeted towards novel BRAFV600 mutations, might offer promising advancements in eGB treatment strategies.
Asunto(s)
Neoplasias Encefálicas , Glioblastoma , Mutación , Inhibidores de Proteínas Quinasas , Proteínas Proto-Oncogénicas B-raf , Humanos , Proteínas Proto-Oncogénicas B-raf/genética , Masculino , Adulto , Glioblastoma/genética , Glioblastoma/tratamiento farmacológico , Glioblastoma/patología , Inhibidores de Proteínas Quinasas/uso terapéutico , Inhibidores de Proteínas Quinasas/farmacología , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/tratamiento farmacológico , Neoplasias Encefálicas/patología , Quinasas de Proteína Quinasa Activadas por Mitógenos/antagonistas & inhibidores , Quinasas de Proteína Quinasa Activadas por Mitógenos/metabolismo , Quinasas de Proteína Quinasa Activadas por Mitógenos/genéticaRESUMEN
BACKGROUND: Abdominal sarcomas are a heterogeneous group of rare soft tissue tumors and can be localized intraperitoneally or retroperitoneally. A pretherapeutic differentiated subtyping is essential for planning an individual, multimodal treatment concept in an interdisciplinary team of experts. OBJECTIVE: The central aspects of histology acquisition, imaging diagnostics and (molecular) pathological subtyping of abdominal soft tissue sarcomas are described in detail. MATERIAL AND METHODS: Imaging and pathological diagnostics are depicted based on the German S3 guidelines on adult soft tissue sarcomas, a current literature search and personal experiences at the Sarcoma Center at the National Center for Tumor Diseases in Dresden (NCT/UCC). RESULTS: Preoperative imaging and (molecular) pathological subtyping of abdominal soft tissue sarcomas place high demands on surgeons, radiologists and pathologists. Genome analyses of sarcomas have the potential to identify points of attack for individualized treatment options. The limitations of resectability can only be assessed by experienced sarcoma surgeons at specialized centers. CONCLUSION: The treatment of abdominal soft tissue sarcomas at an experienced center is associated with a better prognosis. Even at the first suspicion of an abdominal sarcoma, a referral to an experienced center should be made in order to guarantee optimal expertise in diagnostics and treatment.
Asunto(s)
Sarcoma , Neoplasias de los Tejidos Blandos , Adulto , Terapia Combinada , Humanos , Pronóstico , Derivación y Consulta , Sarcoma/cirugía , Neoplasias de los Tejidos Blandos/cirugíaRESUMEN
BACKGROUND: The influenza virus (IV)-associated mortality and morbidity remains high in Europe. OBJECTIVE: This article gives an overview of the pathogenesis, diagnostics and treatment optimization strategies according to the currently existing guidelines and clinical trials. MATERIAL AND METHODS: Literature search and analysis of national and international guidelines for the epidemiology, diagnostics, treatment and prevention of IV infections. RESULTS AND CONCLUSION: Although the incidence of IV infections remains underrecognized, it is the leading infectious disease-associated cause of mortality and morbidity in Europe. Viruses are mainly transmitted by aerosol inhalation and can cause a wide spectrum of symptoms, ranging from mild signs of a cold to severe respiratory failure requiring mechanical ventilation. The clinical diagnosis should be verified through a PCR-based test in patients with indications for treatment. Neuraminidase inhibitors are currently the treatment of choice for IV infections. Seasonal influenza vaccination is an efficient preventive method. It is therefore imperative to improve vaccination rates in Germany, which have been continuously declining since the pandemic of 2009/2010.
Asunto(s)
Antivirales/uso terapéutico , Vacunas contra la Influenza/administración & dosificación , Gripe Humana/tratamiento farmacológico , Gripe Humana/prevención & control , Neuraminidasa/uso terapéutico , Europa (Continente)/epidemiología , Humanos , Gripe Humana/diagnóstico , Gripe Humana/epidemiología , Morbilidad , Pandemias , Neumonía Viral/diagnóstico , Neumonía Viral/tratamiento farmacológico , Síndrome de Dificultad RespiratoriaAsunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Mutación/genética , Síndromes Mielodisplásicos/tratamiento farmacológico , Síndromes Mielodisplásicos/genética , Proteínas Nucleares/genética , Anciano , Antraciclinas/uso terapéutico , Citarabina/uso terapéutico , Femenino , Células Madre Hematopoyéticas/efectos de los fármacos , Humanos , Masculino , Persona de Mediana Edad , NucleofosminaAsunto(s)
Evolución Clonal , Trasplante de Células Madre Hematopoyéticas/efectos adversos , Leucemia Mieloide Aguda/genética , Preleucemia/genética , Adulto , Femenino , Humanos , Donadores Vivos , Masculino , Persona de Mediana Edad , Preleucemia/tratamiento farmacológico , Preleucemia/terapia , Acondicionamiento Pretrasplante , Secuenciación del ExomaRESUMEN
Neural stem cells in the subventricular zone (SVZ) of the lateral ventricles give rise to new interneurons of the olfactory bulb (OB) throughout life. SVZ/OB neurogenesis is influenced by olfactory network activity, which modulates the survival of new neurons during their integration into the OB network. Previous work suggested that such activity-dependent survival is regulated via the CREB signalling pathway. Curiously, CREB signalling is already active during the early developmental stages of adult SVZ/OB neurogenesis. To investigate the role of cell autonomous CREB signalling during early stages of adult SVZ/OB neurogenesis, we ablated CREB-pathway activity in the SVZ/OB neurogenic lineage using a retroviral strategy. Surprisingly, loss of CREB signalling resulted in increased cell death and loss of expression of the neurogenic transcription factor Pax 6, and of a subset of neuronal proteins in migrating neurons of the RMS. Moreover, post-migratory neurons in the OB displayed impaired dendritic development. These results demonstrate an essential role for CREB signalling in maturation of newborn neurons in the OB and uncover a novel role for CREB signalling in the survival and maintenance of neuronal gene expression during the early stages of SVZ/OB neurogenesis.
Asunto(s)
Supervivencia Celular , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Ventrículos Laterales/anatomía & histología , Células-Madre Neurales/fisiología , Neurogénesis/fisiología , Neuronas/fisiología , Transducción de Señal/fisiología , Animales , Encéfalo/citología , Encéfalo/fisiología , Diferenciación Celular/fisiología , Linaje de la Célula , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/genética , Proteínas del Ojo/genética , Proteínas del Ojo/metabolismo , Femenino , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Ventrículos Laterales/fisiología , Ratones , Ratones Endogámicos C57BL , Células-Madre Neurales/citología , Neuronas/citología , Bulbo Olfatorio/citología , Bulbo Olfatorio/fisiología , Factor de Transcripción PAX6 , Factores de Transcripción Paired Box/genética , Factores de Transcripción Paired Box/metabolismo , Proteínas Represoras/genética , Proteínas Represoras/metabolismoRESUMEN
Meckel-Gruber syndrome (MKS) is an autosomal recessive disorder causing severe defects in the developing central nervous system and other organs. Recently, mutations in the MKS1 gene have been identified as disease causing in individuals of Finnish MKS families. The primary aim of the present study was to assess the frequency of the 'Finnish founder mutation' (29 bp IVS15-7_35) in the MKS1 gene in 20 aborted fetuses with a diagnosis of MKS. The secondary aim was to screen for novel mutations in the coding sequence of the MKS1 gene of MKS fetuses and to obtain genotype-phenotype correlations where possible. Furthermore, we evaluated the carrier rate of a deletion of 29 bp in intron 15 of the MKS1 gene in a German population. To identify and characterize mutations in the MKS1 gene, sequence analyses and quantitative real time polymerase chain reaction studies were performed. We could identify the same type of mutation, a deletion of 29 bp in intron 15 of the MKS1 gene, in 8 out of the 20 cases studied. Six out of the eight cases with such a mutation displayed the campomelic variant of MKS. The carrier frequency among 519 healthy German individuals was 1:260. This deletion in the MKS1 gene is highly associated with a distinct subtype of the MKS, namely the campomelic variant. In individuals of European origin suffering from the campomelic MKS variant, the described deletion is highly likely to be causative. Regarding the results of our study, the incidence of MKS in Germany can be estimated as 1:135,000. In families with a known mutation in the MKS1 gene, it is now possible to offer an early prenatal testing, for example with chorionic villus sampling and mutation analysis.
Asunto(s)
Anomalías Múltiples/genética , Sistema Nervioso Central/anomalías , Intrones , Polidactilia/genética , Proteínas/genética , Eliminación de Secuencia , Feto Abortado/diagnóstico por imagen , Secuencia de Bases , Análisis Mutacional de ADN , Femenino , Frecuencia de los Genes , Pruebas Genéticas , Humanos , Masculino , Datos de Secuencia Molecular , Radiografía , SíndromeRESUMEN
BACKGROUND: The aim of our pilot study was to evaluate effects of an interdisciplinary training program for adult psoriasis patients after six months follow-up. SUBJECTS AND METHODS: Eleven patients with psoriasis participated in an interdisciplinary training program over a weekend taught by dermatologists, psychologists/psychiatrists, and dieticians. Six months follow-up was performed with a questionnaire. RESULTS: The knowledge acquired improved the cooperation with the treating dermatologist (7 of 11), the patients' ability to cope with their disease (11 of 11), and their ability to improving their health status (8 of 11). Their general well-being was increased (9 of 11) and they could better care for their skin disease because they better understood the need for care (9 of 11), and could better judge the best approach for various levels of disease activity (8 of 11). CONCLUSION: These data show early benefits and suggest such a longer lasting effect of this type of psoriasis training and prevention program. Further studies with larger samples and control parameters will have to examine if these results can be confirmed.
Asunto(s)
Grupo de Atención al Paciente/organización & administración , Educación del Paciente como Asunto/métodos , Psoriasis/psicología , Psoriasis/terapia , Adaptación Psicológica , Adulto , Femenino , Estudios de Seguimiento , Alemania/epidemiología , Humanos , Masculino , Proyectos Piloto , Psoriasis/epidemiología , Resultado del TratamientoRESUMEN
OBJECTIVE: To describe the prenatal phenotype of the 11q deletion syndrome (Jacobsen syndrome) and present the molecular characterization of the deletion in the case presented. CASE: Ultrasound at 18 and 20 weeks of gestation, on a 34-year-old woman who presented for amniocentesis, revealed slow movements, oligohydramnios and dilatation of the cerebral ventricles in the fetus. Maternal and paternal ages were 34 and 38 years, respectively. RESULTS: Prenatal karyotyping of cultured amniotic fluid cells revealed an 11q terminal deletion, 46,XX,del(11)(q23) (Jacobsen syndrome). Real-time quantitative PCR analysis was used to identify and map the breakpoint physically to a 45-kb region located 14.5 Mb from the 11q telomere. Polymorphic DNA marker analysis showed that DNA sequences on the paternally derived chromosome are deleted. At autopsy, facial dysmorphism without major malformations was recorded. Examination of the internal organs disclosed the following abnormalities: a Meckels' diverticulum of 4-mm length, adhesion between the gall bladder and the transverse colon, and bilaterally bilobed lungs without further situs anomalies. CONCLUSION: Our case demonstrates significant phenotypic variability of Jacobsen syndrome at midtrimester pregnancy; the syndrome may be manifested at this stage only by mild to moderate ventriculomegaly of the brain.
Asunto(s)
Anomalías Múltiples/genética , Deleción Cromosómica , Cromosomas Humanos Par 11/genética , Anomalías Craneofaciales/genética , Enfermedades Fetales/genética , Ultrasonografía Prenatal , Anomalías Múltiples/diagnóstico por imagen , Adulto , Anomalías Craneofaciales/diagnóstico por imagen , Femenino , Enfermedades Fetales/diagnóstico por imagen , Humanos , Fenotipo , EmbarazoRESUMEN
Adverse effects on the pulmonary circulation in obstructive sleep disordered breathing (SDB) may place children with heart lesions affecting the right ventricle at increased risk for morbidity and mortality. We examined the distribution and effects of SDB in pediatric patients with tetralogy of Fallot (TOF). Families of 37 pediatric patients with TOF completed a survey of cardiac symptoms and school performance as well as a Pediatric Sleep Questionnaire (PSQ), a validated questionnaire for the screening of SDB in children 2-18 years of age. Medical records were reviewed for growth parameters, medical history, and most recent electrocardiogram (ECG) findings. Data from patients with SDB (PSQ score > or = 8, n = 14) were compared to data from patients without SDB (PSQ score < 8; n = 23). The prevalence of SDB in this population (38%) was significantly higher than the published prevalence of 5% in a healthy general pediatric population (p < 0.001). No significant difference was found in age, gender, or age and sex standardized body mass index between patients with or without SDB. No difference was seen in medication use or timing of surgical repair, whether primary or palliative. Patients with SDB had a significantly higher cardiac symptom score (p = 0.01) and increasing PSQ scores correlated with worsening cardiac symptom scores (p = 0.006). Increasing PSQ scores also correlated with worsening school performance (p = 0.001). No differences were seen in ECG data. The screened prevalence of SDB in the pediatric population with TOF is higher than in the general population; patients with TOF and SDB are more likely to have worse cardiac symptoms and poor school performance.
Asunto(s)
Apnea Obstructiva del Sueño/epidemiología , Tetralogía de Fallot/complicaciones , Adolescente , Niño , Preescolar , Estudios de Cohortes , Escolaridad , Electrocardiografía , Tolerancia al Ejercicio , Femenino , Humanos , Masculino , Prevalencia , Factores de Riesgo , Tetralogía de Fallot/fisiopatología , Estados Unidos/epidemiologíaRESUMEN
Plasmid-encoded resistance to broad-spectrum cephalosporins and aztreonam is becoming a widespread phenomenon in clinical medicine. These antibiotics are inactivated by an array of different extended-spectrum beta-lactamases (ESBLs) which have evolved by point mutations of parental TEM or SHV beta-lactamases. In a previous study conducted during 1994-1995, SHV-2, SHV-2a and SHV-5 beta-lactamases were found among Klebsiella pneumoniae isolates in Dubrava University Hospital. High prevalence of ESBLs among K. pneumoniae strains in this hospital (20%) required further investigation. In this investigation, beta-lactamases from 42 K. pneumoniae strains collected in 1997 and 15 in 2004 from Dubrava University Hospital, were characterized in order to study the evolution of plasmid-encoded resistance to extended-spectrum cephalosporins and aztreonam in that hospital over a prolonged study period. Susceptibility to antibiotics was determined by disk-diffusion and broth microdilution method. beta-lactamases were characterized by isoelectric focusing, determination of hydrolysis of beta-lactam substrates, polymerase chain reaction and sequencing of bla(SHV) genes. All K. pneumoniae strains and their Escherichia coli transconjugants produced beta-lactamase with an isoelectric point of 8.2. Based on sequencing of bla(SHV) genes enzymes of all transconjugants were identified as SHV-5 beta-lactamase which conferred on the producing isolates high level of ceftazidime and aztreonam resistance. In this study, an outbreak of nosocomial infections caused by SHV-5 producing K. pneumoniae was described in 1997 which evolved to endemic spread of SHV-5 producing K. pneumoniae due to multiple plasmid transfer in the Dubrava University Hospital. The strains from 1997 and 2004 were not clonally related. Hospital hygiene measures should be applied in order to control the spread of epidemic strains through the hospital wards and the consumption of the broad-spectrum cephalosporins needs to be restricted to reduce the selection pressure which enables the proliferation of ESBL producers in hospital.
Asunto(s)
Antibacterianos/farmacología , Infección Hospitalaria/epidemiología , Infecciones por Klebsiella/epidemiología , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/enzimología , beta-Lactamasas/metabolismo , Técnicas de Tipificación Bacteriana , Croacia/epidemiología , Infección Hospitalaria/microbiología , ADN Bacteriano , Farmacorresistencia Bacteriana Múltiple , Electroforesis en Gel de Campo Pulsado , Enfermedades Endémicas , Femenino , Hospitales Universitarios , Humanos , Infecciones por Klebsiella/diagnóstico , Klebsiella pneumoniae/clasificación , Masculino , Pruebas de Sensibilidad Microbiana , Reacción en Cadena de la Polimerasa , Prevalencia , Estudios Retrospectivos , Factores de RiesgoRESUMEN
Nitrogen monoxide (nitric oxide) generated endogenously has a variety of different properties. Among others it regulates blood pressure and transmission of nerve impulses, and has been shown to exert specific toxic effects, but also, paradoxically, to protect against various toxic substances. Recent studies suggest that NO* can serve as an antioxidant of the highly oxidizing ferryl myoglobin (MbFe(IV)=O), which has been proposed to be at least in part responsible for the oxidative damage caused by the reperfusion of ischemic tissues. In the present work we have determined the rate constant for the reaction between MbFe(IV)=O and NO* [(17.9+/-0.5)x10(6)M(-1)s(-1) at pH 7.5 and 20 degrees C] and we have shown that this reaction proceeds via the intermediate nitrito-metmyoglobin complex MbFe(III)ONO. Our results imply that this reaction is very likely to take place in vivo and might indeed represent a detoxifying pathway for both MbFe(IV)=O as well as NO*. Moreover, we have found that the rate of reaction of MbFe(IV)=O with nitrite is significantly lower (16+/-1 M(-1) s(-1) at pH 7.5 and 20 degrees C). Thus, this reaction probably plays a role only when NO* has been consumed completely and large concentrations of nitrite are still present. In contrast to the protecting role of NO*, the reaction with nitrite generates nitrogen dioxide which can contribute to tyrosine nitration. Indeed, we have demonstrated that nitrite can nitrate added tyrosine in the presence of iron(III) myoglobin and hydrogen peroxide.
Asunto(s)
Metamioglobina/química , Óxido Nítrico/química , Nitritos/química , Tirosina/análogos & derivados , Cinética , Mecánica , Metamioglobina/metabolismo , Oxidación-Reducción , Espectrofotometría Ultravioleta , Tirosina/análisis , Tirosina/química , Tirosina/metabolismoAsunto(s)
Mioglobina/química , Nitratos/química , Animales , Isomerismo , Mutación , Mioglobina/genética , Espectrofotometría Ultravioleta , BallenasRESUMEN
The second-order rate constants for the reactions between nitrogen monoxide and oxymyoglobin or oxyhemoglobin, determined by stopped-flow spectroscopy, increase with increasing pH. At pH 7.0 the rates are (43.6 +/- 0.5) x 10(6) M(-1) x s(-1) for oxymyoglobin and (89 +/- 3) x 10(6) M(-1) x s(-1) for oxyhemoglobin (per heme), whereas at pH 9.5 they are (97 +/- 3) x 10(6) M(-1) x s(-1) and (144 +/- 3) x 10(6) M(-1) x s(-1), respectively. The rate constants for the reaction between oxyhemoglobin and NO* depend neither on the association grade of the protein (dimer/tetramer) nor on the concentration of the phosphate buffer (100-1 mM). The nitrogen monoxide-mediated oxidations of oxymyoglobin and oxyhemoglobin proceed via intermediate peroxynitrito complexes which were characterized by rapid scan UV/vis spectroscopy. The two complexes MbFe(III)OONO and HbFe(III)OONO display very similar spectra with absorption maxima around 500 and 635 nm. These species can be observed at alkaline pH but rapidly decay to the met-form of the proteins under neutral or acidic conditions. The rate of decay of MbFe(III)OONO increases with decreasing pH and is significantly larger than those of the analogous complexes of the two subunits of hemoglobin. No free peroxynitrite is formed during these reactions, and nitrate is formed quantitatively, at both pH 7.0 and 9.0. This result indicates that, as confirmed from protein analysis after reacting the proteins with NO* for 10 times, when peroxynitrite is coordinated to the heme of myoglobin or hemoglobin it rapidly isomerizes to nitrate without nitrating the globins in physiologically significant amounts.
Asunto(s)
Mioglobina/química , Óxido Nítrico/química , Oxihemoglobinas/química , Animales , Cromatografía Líquida de Alta Presión , Caballos , Humanos , Concentración de Iones de Hidrógeno , Cinética , Ligandos , Metamioglobina/química , Nitratos/química , Dióxido de Nitrógeno/química , Oxidación-Reducción , Espectrofotometría Ultravioleta , Análisis EspectralRESUMEN
The evaluation of monocytes recruited into the alveolar space under both physiological and inflammatory conditions is hampered by difficulties in discriminating these cells from resident alveolar macrophages (rAMs). Using the intravenous injected fluorescent dye PKH26, which accumulated in rAMs without labeling blood leukocytes, we developed a technique that permits the identification, isolation, and functional analysis of monocytes recruited into lung alveoli of mice. Alveolar deposition of murine JE, the homologue of human monocyte chemoattractant protein (MCP)-1 (JE/MCP-1), in mice provoked an alveolar influx of monocytes that were recovered by bronchoalveolar lavage and separated from PKH26-stained rAMs by flow cytometry. Alveolar recruited monocytes showed a blood monocytic phenotype as assessed by cell surface expression of F4/80, CD11a, CD11b, CD18, CD49d, and CD62L. In contrast, CD14 was markedly upregulated on alveolar recruited monocytes together with increased tumor necrosis factor-alpha message, discriminating this monocyte population from peripheral blood monocytes and rAMs. Thus monocytes recruited into the alveolar air space of mice in response to JE/MCP-1 keep phenotypic features of blood monocytes but upregulate CD14 and are "primed" for enhanced responsiveness to endotoxin with increased cytokine expression.
Asunto(s)
Receptores de Lipopolisacáridos/metabolismo , Monocitos/inmunología , Monocitos/metabolismo , Compuestos Orgánicos , Alveolos Pulmonares/inmunología , Animales , Movimiento Celular/efectos de los fármacos , Movimiento Celular/inmunología , Separación Celular , Quimiocina CCL2/farmacología , Femenino , Citometría de Flujo , Colorantes Fluorescentes , Expresión Génica/inmunología , Inmunofenotipificación , Receptores de Lipopolisacáridos/inmunología , Macrófagos Alveolares/citología , Macrófagos Alveolares/inmunología , Ratones , Ratones Endogámicos BALB C , Monocitos/citología , Alveolos Pulmonares/citología , ARN Mensajero/análisis , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/inmunología , Factor de Necrosis Tumoral alfa/metabolismo , Regulación hacia Arriba/inmunologíaRESUMEN
Peroxynitrite (PN) is likely to be generated in vivo from nitric oxide and superoxide. We have previously shown that prostacyclin synthase, a heme-thiolate enzyme essential for regulation of vascular tone, is nitrated and inactivated by submicromolar concentrations of PN [Zou, M.-H. & Ullrich, V. (1996) FEBS Lett. 382, 101-104] and we have studied the effect of heme proteins on the PN-mediated nitration of phenolic compounds in model systems [Mehl, M., Daiber, A. & Ullrich, V. (1999) Nitric Oxide: Biol. Chem. 2, 259-269]. In the present work we show that bolus additions of PN or PN-generating systems, such as SIN-1, can induce the nitration of P450BM-3 (wild-type and F87Y variant), for which we suggest an autocatalytic mechanism. HPLC and MS-analysis revealed that the wild-type protein is selectively nitrated at Y334, which was found at the entrance of a water channel connected to the active site iron center. In the F87Y variant, Y87, which is directly located at the active site, was nitrated in addition to Y334. According to Western blots stained with a nitrotyrosine antibody, this nitration started at 0.5 microM of PN and was half-maximal between 100 and 150 microM of PN. Furthermore, PN caused inactivation of the P450BM-3 monooxygenase as well as the reductase activity with an IC50 value of 2-3 microM. As two thiol residues/protein molecule were oxidized by PN and the inactivation was prevented by GSH or dithiothreitol, but not by uric acid (a powerful inhibitor of the nitration), our data strongly indicate that the inactivation is due to thiol oxidation at the reductase domain rather then to nitration of Y residues. Stopped-flow data presented here support our previous hypothesis that ferryl-species are involved as intermediates during the reactions of P450 enzymes with PN.
Asunto(s)
Proteínas Bacterianas , Sistema Enzimático del Citocromo P-450/química , Sistema Enzimático del Citocromo P-450/metabolismo , Hierro/metabolismo , Oxigenasas de Función Mixta/química , Oxigenasas de Función Mixta/metabolismo , Nitratos/farmacología , Nitrógeno/metabolismo , Tirosina/análogos & derivados , Animales , Bacillus/enzimología , Sitios de Unión , Western Blotting , Bovinos , Cromatografía Líquida de Alta Presión , Ditiotreitol/farmacología , Relación Dosis-Respuesta a Droga , Eritrocitos/enzimología , Glutatión/metabolismo , Concentración 50 Inhibidora , Hierro/química , Espectrometría de Masas , Modelos Químicos , Modelos Moleculares , Molsidomina/análogos & derivados , Molsidomina/farmacología , NADPH-Ferrihemoproteína Reductasa , Donantes de Óxido Nítrico/farmacología , Nitrógeno/química , Oxígeno/metabolismo , Superóxido Dismutasa/metabolismo , Temperatura , Factores de Tiempo , Tirosina/metabolismo , Ácido Úrico/farmacologíaRESUMEN
According to Khan et al. [Khan, A. U., Kovacic, D., Kolbanovskiy, A., Desai, M., Frenkel, K. & Geacintov, N. E. (2000) Proc. Natl. Acad. Sci. USA 97, 2984-2989], peroxynitrite (ONOO(-)) decomposes after protonation to singlet oxygen ((1)Delta(g)O(2)) and singlet oxonitrate (nitroxyl, (1)NO(-)) in high yield. They claimed to have observed nitrosyl hemoglobin from the reaction of NO(-) with methemoglobin; however, contamination with hydrogen peroxide gave rise to ferryl hemoglobin, the spectrum of which was mistakenly assigned to nitrosyl hemoglobin. We have carried out UV-visible and EPR experiments with methemoglobin and hydrogen peroxide-free peroxynitrite and find that no NO(-) is formed. With this peroxynitrite preparation, no light emission from singlet oxygen at 1270 nm is observed, nor is singlet oxygen chemically trapped; however, singlet oxygen was trapped when hydrogen peroxide was also present, as previously described [Di Mascio, P., Bechara, E. J. H., Medeiros, M. H. G., Briviba, K. & Sies, H. (1994) FEBS Lett. 355, 287-289]. Quantum mechanical and thermodynamic calculations show that formation of the postulated intermediate, a cyclic form of peroxynitrous acid (trioxazetidine), and the products (1)NO(-) and (1)Delta(g)O(2) requires Gibbs energies of ca. +415 kJ .mol(-1) and ca. +180 kJ.mol(-1), respectively. Our results show that the results of Khan et al. are best explained by interference from contaminating hydrogen peroxide left from the synthesis of peroxynitrite.
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Nitratos/química , Óxidos de Nitrógeno/química , Oxígeno , Cromatografía Líquida de Alta Presión , Espectrometría de Masas , Oxígeno SingleteRESUMEN
Endothelial synthesis of the C-C chemokine monocyte chemotactic protein-1 (MCP-1) has been implicated in the regulation of monocyte recruitment for extravascular pools under both physiologic and inflammatory conditions. We designed and characterized five antisense phosphorothioate oligodeoxynucleotides (PS-ODN) targeting MCP-1 secretion by human pulmonary artery endothelial cells (HPAEC) and pulmonary microvascular endothelial cells (HMVEC-L). The most effective PS-ODN (MCP-1 AS 2) dose-dependently suppressed the secretion of MCP-1 but not the secretion of the C-X-C chemokine interleukin-8 (IL-8) in both HPAEC and HMVEC-L in the nanomolar concentration range. Mismatch controls bearing 2 or 4 bp substitutions showed markedly reduced inhibitory capacity. MCP-1 mRNA levels were not affected even at the highest PS-ODN doses employed (ribonuclease protection assay), suggesting a translational arrest of MCP-1 production. Accordingly, PS-ODN exhibited no nonspecific side effects on immediate-early gene regulation of the transcription factor nuclear factor-kappaB (NF-kappaB), as analyzed by gel shift assays. Antisense pretreatment of HPAEC reduced the monocyte chemotactic bioactivity liberated from tumor necrosis factor-alpha (TNF-alpha)-activated endothelial cells (EC) and reduced the TNF-alpha-induced transendothelial monocyte migration. We conclude that nanomolar concentrations of specific antisense oligodeoxynucleotides effectively inhibit human endothelial MCP-1 synthesis and may thus provide a rational approach to modulate monocyte recruitment under inflammatory conditions.
Asunto(s)
Quimiocina CCL2/antagonistas & inhibidores , Quimiocina CCL2/biosíntesis , Endotelio Vascular/efectos de los fármacos , Endotelio Vascular/metabolismo , Pulmón/irrigación sanguínea , Oligodesoxirribonucleótidos Antisentido/farmacología , Inhibidores de la Síntesis de la Proteína/farmacología , Línea Celular , Movimiento Celular/efectos de los fármacos , Quimiocina CCL2/genética , Medios de Cultivo Condicionados/metabolismo , Endotelio Vascular/citología , Humanos , Interleucina-8/biosíntesis , Pulmón/citología , Pulmón/efectos de los fármacos , Pulmón/metabolismo , FN-kappa B/metabolismo , Oligodesoxirribonucleótidos Antisentido/metabolismo , Inhibidores de la Síntesis de la Proteína/metabolismo , Arteria Pulmonar , Venas Pulmonares , ARN Mensajero/efectos de los fármacos , ARN Mensajero/metabolismoRESUMEN
Kinetic studies of the peroxynitrite-mediated oxidations of oxymyoglobin (MbFeO(2)) and oxyhemoglobin (HbFeO(2)) showed that the mechanisms of these reactions are more complex than what had previously been reported; both reactions proceed in two steps. For myoglobin, we found that the small amount of deoxymyoglobin (MbFe(II)) which is in equilibrium with MbFeO(2) is first oxidized by peroxynitrous acid to ferryl myoglobin (MbFe(IV)=O). Then, in the second step, MbFe(IV)=O is reduced by peroxynitrous acid to metmyoglobin (metMb). The second-order rate constant values obtained at pH 7.3 and 20 degrees C for the two steps are (5.4 +/- 0.2) x 10(4) and (2.2 +/- 0.1) x 10(4) M(-)(1) s(-)(1), respectively. Analogous studies with hemoglobin suggest that its reaction with peroxynitrite follows the same mechanism. In this case, the second-order rate constant values measured at pH 7.0 and 20 degrees C for the two steps are (8.8 +/- 0.4) x 10(4) and (9.4 +/- 0.7) x 10(4) M(-)(1) s(-)(1), respectively. A possible mechanism in the absence as well as in the presence of CO(2) and the relevance of these reactions in vivo are discussed.