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1.
J Viral Hepat ; 23(4): 256-66, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26537061

RESUMEN

Membrane type 1 matrix metalloproteinase (MT1-MMP) binds to and regulates the function of tetraspanin-enriched microdomains. It also physically interacts with claudin-1 and acireductone dioxygenase 1 (ADI1), both associated with hepatitis C virus (HCV) cell entry. Here, we examined hepatic expression of MT1-MMP, ADI1 and claudin-1 as well as their physical interaction in relation to serum or intrahepatic HCV-RNA levels. A total of 104 liver biopsies obtained from chronic hepatitis C patients and 84 liver tissues obtained from noncancerous parts of surgically removed HCV-related hepatocellular carcinoma were analysed. Positive cytoplasmic ADI1 in liver biopsies was associated with higher serum HCV-RNA levels (P = 0.009). Positive MT1-MMP and ADI1 interaction assessed by co-immunoprecipitation was associated with lower tissue HCV-RNA levels (P = 0.009). Hepatic HCV-RNA levels were positively associated with ADI1 levels in the MT1-MMP and ADI1 co-immunoprecipitates (P = 0.030). Overexpression of MT1-MMP in Huh7.5 cells suppressed cell entry of HCV pseudoparticles as well as HCVcc infection. The suppression effect could be reversed by co-expression of ADI1 in a dose-dependent manner. In summary, clinical and cell-based experiments suggested that physical interaction between MT1-MMP and ADI1 led to suppression of HCV infection. This inhibitory effect could be reversed by ADI1 overexpression.


Asunto(s)
Dioxigenasas/análisis , Hepatitis C Crónica/patología , Hepatitis C Crónica/virología , Metaloproteinasa 14 de la Matriz/análisis , ARN Viral/análisis , Adulto , Anciano , Anciano de 80 o más Años , Biopsia , Línea Celular , Claudina-1/análisis , Femenino , Hepatocitos/enzimología , Hepatocitos/virología , Humanos , Hígado/patología , Hígado/virología , Masculino , Persona de Mediana Edad , Plasma/virología , Carga Viral
2.
J Viral Hepat ; 19(2): e154-62, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22239513

RESUMEN

Antiviral effect of interferon is mediated by the expression of interferon-stimulated genes (ISGs). However, because of the difficulty in obtaining paired liver biopsies before and after interferon treatment, the key ISGs expressed in human hepatocytes and responsible for interferon-based antiviral activities in chronic hepatitis C remain illusive. Prior to a standard course of peginterferon plus ribavirin therapy, 104 patients underwent a liver biopsy. A small piece of the liver biopsy sample from each patient was submitted for ex vivo tissue culture in the presence or absence of interferon. Hepatic expression of 8 ISGs was detected by RT-PCR. The ISG expression patterns and clinicopathological variables were correlated with subsequent treatment outcomes. Multivariate logistic regression analysis showed that hepatic MxA expression (P = 0.008) and leucocyte count (P = 0.040) independently predicted the end of therapeutic virological response, while hepatic OAS1 expression (P = 0.003), genotype 1 (P = 0.002), HCV-RNA level (P = 0.007), AST/ALT ratio (P = 0.004) and leucocyte count (P = 0.034) independently predicted the sustained virological response. Immunohistochemistry analysis showed that interferon-induced OAS1 expression localized to the hepatocytes. In conclusion, hepatic MxA and OAS1 expression predicted, respectively, the end of therapeutic and sustained virological responses in interferon-based treatment of chronic hepatitis C.


Asunto(s)
2',5'-Oligoadenilato Sintetasa/biosíntesis , Proteínas de Unión al GTP/biosíntesis , Expresión Génica , Hepatitis C Crónica/tratamiento farmacológico , Hepatitis C Crónica/patología , Interferones/administración & dosificación , Hígado/patología , Adulto , Antivirales/administración & dosificación , Biopsia , Células Cultivadas , Femenino , Humanos , Inmunohistoquímica , Factores Inmunológicos/administración & dosificación , Masculino , Persona de Mediana Edad , Proteínas de Resistencia a Mixovirus , Ribavirina/administración & dosificación , Resultado del Tratamiento
3.
Nanotechnology ; 21(13): 134008, 2010 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-20208118

RESUMEN

Pt contact on p-Si nanowires (NWs) using Ga-ion-induced deposition by a focused ion beam was formed with a specific contact resistance (rho(c)) of 1.54 x 10(-6) Omega cm(2). Ohmic behavior is caused by Ga-ion-induced amorphization of Si NWs underneath the Pt contact. A very low Schottky barrier height associated with interface states raised from Pt-amorphized Si junction and with an image force induced by the applied bias can be implemented to elucidate ultralow rho(c). The value of rho(c) lower than that of any known contact to Si NWs demonstrates a practical method for integrating NWs in devices and circuits.

4.
Clin Microbiol Infect ; 26(3): 366-372, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31229596

RESUMEN

OBJECTIVES: The prevalence and factors of hepatitis C virus (HCV) -associated mixed cryoglobulinaemia in Asia remain elusive, and we aimed to investigate these topics. METHODS: An 8-year prospective cohort study was conducted in 678 consecutive Taiwanese individuals with chronic HCV infection (438 completed an anti-HCV therapy course). RESULTS: Of 678 individuals, 437 (64.5%) had mixed cryoglobulinaemia and 20 (2.9%) had mixed cryoglobulinaemic syndrome. At baseline, IgM (cut-off >122 mg/dL), triglycerides and IgG levels, and HCV genotype 3 were independently associated with mixed cryoglobulinaemia. Rheumatoid factor (RF) levels were associated with mixed cryoglobulinaemic syndrome (cut-off >12.2 IU/mL). At 24 weeks post-therapy, the 362 individuals with a sustained virological response (SVR) had higher cured (106/362 (29.3%) versus 10/76 (13.2%), p = 0.003) and lower persistent (100/362 (27.6%) versus 33/76 (43.4%), p = 0.003) mixed cryoglobulinaemia rates than non-SVR patients. Among SVR patients, compared with baseline levels, RF, IgG and IgM levels decreased, except in individuals with new mixed cryoglobulinaemia. Pre-therapy IgM levels were associated with 24-week post-therapy new (95% CI of OR 1.002-1.023) and persistent (95% CI of OR 1.004-1.015) mixed cryoglobulinaemia in SVR patients. After up to 8 years, 24-week post-therapy IgM levels were associated with mixed cryoglobulinaemia in SVR patients (9/51; 17.64%; 95% CI of HR 1.004-1.011). Among 17 SVR patients with pre-therapy mixed cryoglobulinaemic syndrome, 5 (29.4%) had long-term mixed cryoglobulinaemia and 4 (23.5%) had mixed cryoglobulinaemic syndrome. CONCLUSIONS: Over 60% of chronic HCV-infected individuals had mixed cryoglobulinaemia, and 17.64% of SVR patients had mixed cryoglobulinaemia 8 years post-therapy. Pre-therapy RF and IgM levels marked HCV-associated mixed cryoglobulinaemic syndrome and mixed cryoglobulinaemia, respectively.


Asunto(s)
Crioglobulinemia/sangre , Crioglobulinemia/etiología , Hepatitis C/complicaciones , Inmunoglobulina M/sangre , Factor Reumatoide/sangre , Adulto , Anciano , Antivirales/uso terapéutico , Biomarcadores , Crioglobulinemia/diagnóstico , Crioglobulinemia/epidemiología , Femenino , Genotipo , Hepacivirus/clasificación , Hepacivirus/genética , Hepatitis C/tratamiento farmacológico , Hepatitis C/epidemiología , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Curva ROC , Respuesta Virológica Sostenida
5.
J Viral Hepat ; 16(5): 359-66, 2009 May.
Artículo en Inglés | MEDLINE | ID: mdl-19243501

RESUMEN

A liver slice culture-based, ex vivo drug suppression assay was developed as a pre-therapeutic predictor for the outcome of antiviral therapy. To investigate its clinical application, 106 consecutive patients with chronic hepatitis C virus (HCV) infection were evaluated. Ex vivo drug suppression assay was performed before administrating a standard course of peginterferon plus ribavirin combination therapy. Stepwise logistic regression model was used to estimate sustained virological response (SVR) on the presence of various clinicopathological parameters. Suppression of HCV replication in the ex vivo assay was present in 32 patients, 29 (90.6%) of whom achieved SVR. Stepwise logistic regression analysis indicated that the presence of interferon suppression effect in the ex vivo assay (odds ratio [OR], 5.552; 95% confidence interval [CI], 1.114-27.673; P = 0.036), genotype 1 (OR; 0.045, 95% CI, 0.008-0.259; P = 0.001), HCV-RNA level (OR, 0.739; 95% CI, 0.617-0.885; P = 0.001), the presence of fatty metamorphosis (OR, 0.205; 95% CI, 0.053-0.793; P = 0.022), and albumin (OR, 9.687; 95% CI, 2.237-41.940; P = 0.002) were independent determinants of SVR. Categorical analysis revealed that 17 of 17 (100%) patients with genotype non-1 and positive ex vivo suppression test achieved SVR, while 20 of 40 (50%) with genotype 1 and negative ex vivo suppression test achieved SVR. In conclusion, the ex vivo drug suppression assay may serve as an independent pre-therapeutic predictor for the SVR in interferon-based antiviral therapy.


Asunto(s)
Antivirales/farmacología , Hepacivirus/efectos de los fármacos , Hepatitis C Crónica/tratamiento farmacológico , Hígado/virología , Adulto , Albúminas/análisis , Femenino , Genotipo , Hepacivirus/clasificación , Humanos , Hígado/química , Masculino , Persona de Mediana Edad , Técnicas de Cultivo de Órganos/métodos , Valor Predictivo de las Pruebas , Estudios Prospectivos , ARN Viral/análisis
6.
J Viral Hepat ; 15(11): 839-48, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-18647234

RESUMEN

The aim of this case control study was to investigate the clinical significance of hepatitis B virus nuclear core antigen (HBcAg) in young cirrhotic patients. Fifteen cirrhotic patients with nuclear HBcAg in the liver biopsies were included. Their clinicopathological parameters as well as the core gene sequences were compared with those of a sex- and age-matched (1 to 2) control group. The mean follow-up periods were 124 +/- 80 and 102 +/- 43 months, respectively. Expression of nuclear HBcAg in cirrhotic liver was significantly associated with higher aspartate aminotransferase levels (P = 0.001), alanine aminotransferase levels (P < 0.001), and alpha-fetoprotein levels (P = 0.002), as well as a shorter duration to develop hepatocellular carcinoma or liver decompensation (Kaplan-Meier method, P = 0.044). Sequence analysis revealed mutations on the nuclear localization signal (NLS) of core protein in five cirrhotic patients with nuclear HBcAg (Q171K in four and Q179K in one patients). Site-directed mutagenesis experiments demonstrated that both the Q171K and Q179K mutation enhanced nuclear localization of the core protein. In conclusion, expression of nuclear HBcAg in young cirrhotic patients was associated with more severe hepatitis activities as well as an unfavourable long-term outcome. Mutations on the NLS of core protein were selected in some patients with nuclear HBcAg.


Asunto(s)
Antígenos Nucleares/biosíntesis , Antígenos del Núcleo de la Hepatitis B/biosíntesis , Hepatitis B Crónica/diagnóstico , Cirrosis Hepática/virología , Adulto , Alanina Transaminasa/sangre , Sustitución de Aminoácidos/genética , Antígenos Nucleares/genética , Biopsia , Carcinoma Hepatocelular , Estudios de Casos y Controles , Femenino , Estudios de Seguimiento , Insuficiencia Hepática , Antígenos del Núcleo de la Hepatitis B/genética , Hepatitis B Crónica/mortalidad , Hepatitis B Crónica/patología , Humanos , Cirrosis Hepática/mortalidad , Cirrosis Hepática/patología , Masculino , Persona de Mediana Edad , Mutación Missense , Señales de Localización Nuclear/genética , Pronóstico , Factores de Tiempo , alfa-Fetoproteínas/análisis
7.
AIDS ; 19(13): w1-6, 2005 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-16103763

RESUMEN

Research teams from five countries, Brazil, China, Kenya, Peru and Thailand, have initiated a policy-maker survey on vaccine delivery, cost studies for future HIV vaccination programmes, and associated simulation modeling exercises analysing the relative cost-effectiveness of potential HIV vaccination strategies. The survey assesses challenges and opportunities for future country-level HIV vaccination strategies, providing data on the vaccine characteristics (e.g. vaccine efficacies for susceptibility, infectiousness and disease progression) and vaccination programme strategies to be considered in the cost-effectiveness modeling analyses. The study will provide decision-makers with modeling data on vaccination policy considerations that will assist in developing country-level capacities for future HIV vaccine policy adoption and effective delivery systems, and will help delineate the long-term financial requirements for sustainable HIV vaccination programmes. The WHO-UNAIDS HIV Vaccine Initiative and the collaborating researchers welcome comments or questions from policy makers, health professionals and other stakeholders in the public and private sectors about this effort to help advance policy and capacity related to future potential HIV vaccines.


Asunto(s)
Vacunas contra el SIDA/economía , Infecciones por VIH/prevención & control , Programas de Inmunización/economía , Vacunas contra el SIDA/provisión & distribución , Simulación por Computador , Análisis Costo-Beneficio , Atención a la Salud , Infecciones por VIH/economía , Encuestas de Atención de la Salud , Política de Salud , Accesibilidad a los Servicios de Salud , Humanos , Cooperación Internacional , Modelos Econométricos , Formulación de Políticas
8.
Biochim Biophys Acta ; 420(1): 69-80, 1976 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-1247582

RESUMEN

The molecular makeup of soluble fibrin complexes was studied by gel exclusion chromatography using radio-labelling to characterize individual components in protein mixtures. Products of limited plasmin degradation of fibrinogen and mixtures of fibrinogen and "early" fibrinogen digests formed high molecular weight soluble fibrin complexes upon incubation with thrombin. Purified, nonclottable fragment Y did not incorporate into soluble fibrin complexes, nor could we demonstrate incorporation of fragments D and E as previously described from our laboratory. Thus, under the conditions of these experiments, soluble fibrin complexes have two identifiable components, fibrin monomer and clottable fragment X monomer, although incorporation of native fibrinogen or fragment X unreacted by thrombin into soluble fibrin complexes cannot be excluded. Individual fractions of thrombin-treated early fibrinogen digests isolated by agarose gel chromatography were treated with protamine sulfate at 37 degrees C resulting in precipitation-gelation of greater than 90 per cent of high molecular weight soluble fibrin complexes; whereas, less than 10 per cent of lower molecular weight fibrinogen degradation products precipitated by protamine sulfate. These findings do not support the widely held concept that soluble fibrin complexes incorporate nonclottable degradation products of fibrinogen proteolysis, nor do they support the notion that the so-called paracoagulation reaction induced by protamine sulfate results from the splitting of complexes between fibrin monomer and nonclottable fibrinogen degradation products.


Asunto(s)
Fibrina , Sitios de Unión , Cromatografía en Agarosa , Cromatografía en Gel , Humanos , Sustancias Macromoleculares , Peso Molecular , Protaminas , Unión Proteica , Conformación Proteica , Solubilidad , Trombina
9.
Neuroscience ; 133(2): 423-36, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-15878805

RESUMEN

Between one-third and one-half of all cases of sepsis are known to be caused by gram-positive microorganisms through the cell wall component, e.g. lipoteichoic acid (LTA). Gram-positive bacteria are also known to induce encephalomyelitis and meningeal inflammation, and enhance the production of nitric oxide (NO) via expression of inducible nitric oxide synthase (iNOS) in murine tissue macrophages. It remains to be explored if LTA could activate microglia considered to be resident brain macrophages. We report here that LTA derived from gram-positive bacteria (Staphylococcus aureus) significantly induces NO release and iNOS expression in primary microglia. LTA-induced NO accumulation was detected at 2 h in microglial culture and was significantly attenuated by pretreatment with anti-CD14, complement receptor type 3 (CR3) or scavenger receptor (SR) antibodies. LTA activated mitogen-activated protein kinases (MAPKs) such as extracellular signal-regulated kinase, p38 MAPK or c-Jun N-terminal kinase in cultured microglia. LTA-elicited microglial NO production was also drastically suppressed by SB203580 (p38 MAPK inhibitor) or pyrrolidine dithiocarbamate (an inhibitor of nuclear factor kappaB), indicating that p38 MAPK and nuclear factor kappaB were involved in microglial NO release after LTA challenge. These results suggest that gram-positive bacterial product such as LTA can activate microglia to release NO via the signal transduction pathway involving multiple LTA receptors (e.g. CD14, CR3 or SR), p38 MAPK and nuclear factor kappaB. The in vivo study further confirmed that administered intracerebrally LTA induced considerable noticeable iNOS, phospho-IkappaB and phospho-p38 MAPK expression in microglia/macrophages.


Asunto(s)
Lipopolisacáridos/farmacología , Microglía/efectos de los fármacos , Óxido Nítrico/metabolismo , Transducción de Señal/efectos de los fármacos , Ácidos Teicoicos/farmacología , Animales , Anticuerpos/farmacología , Western Blotting/métodos , Carbidopa/inmunología , Células Cultivadas , Relación Dosis-Respuesta a Droga , Combinación de Medicamentos , Proteínas del Ojo/inmunología , Técnica del Anticuerpo Fluorescente/métodos , Regulación de la Expresión Génica/efectos de los fármacos , Proteínas I-kappa B/metabolismo , Indoles , Lectinas/metabolismo , Levodopa/inmunología , Receptores de Lipopolisacáridos/inmunología , Microglía/enzimología , Proteínas del Tejido Nervioso/inmunología , Óxido Nítrico Sintasa/metabolismo , Óxido Nítrico Sintasa de Tipo II , Nitritos/metabolismo , Ratas , Ratas Wistar , Factores de Tiempo , gamma-Sinucleína , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo
10.
Aliment Pharmacol Ther ; 42(3): 243-57, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26151841

RESUMEN

BACKGROUND: It has been debated whether finite nucleos(t)ide analogue therapy is feasible in HBeAg-negative chronic hepatitis B. AIM: To review this issue systematically. METHODS: Using text terms HBsAg and various nucleos(t)ide analogues, PubMed was searched between 1995 and 2014 to find studies on therapy >6 months in adult HBeAg-negative chronic hepatitis B patients with off-therapy follow-up >6 months. RESULTS: Twenty-two studies with a total of 1732 patients were identified and included. The median duration of therapy, consolidation therapy and off-therapy follow-up ranged from 6 months to 8 years, 4 to 96 weeks and 6 to 80 months respectively. Patients were monitored with serum ALT and HBV DNA monthly in the first 1-3 months and every 3-6 months afterwards in most studies. The 1-year off-therapy 'virological relapse' (HBV DNA >2000 IU/mL) and 'clinical relapse' (HBV DNA > 2000 IU/mL + ALT elevation) occurred in <70% and <50% of the patients, respectively, and <40% of the patients received re-treatment. These rates were higher in patients with shorter treatment, shorter consolidation therapy and those treated with less potent nucleos(t)ide analogues. Off-therapy severe flares were rare and hepatic decompensation was reported in only one patient with cirrhosis. Biochemical relapse reflecting enhanced immune-mediated hepatocyte killing may lead to a higher chance for off-therapy HBsAg seroclearance and be possibly desirable. CONCLUSION: With an appropriate stopping rule and a proper off-therapy monitoring plan, cessation of long-term nucleos(t)ide analogue therapy prior to HBsAg seroclearance in HBeAg-negative chronic hepatitis B is a feasible alternative to indefinite treatment.


Asunto(s)
Antivirales/uso terapéutico , Antígenos e de la Hepatitis B/sangre , Hepatitis B Crónica/tratamiento farmacológico , Adulto , Antígenos de Superficie de la Hepatitis B/sangre , Humanos , Cirrosis Hepática/virología , Recurrencia , Resultado del Tratamiento
11.
AIDS ; 17(15): W1-10, 2003 Oct 17.
Artículo en Inglés | MEDLINE | ID: mdl-14523295

RESUMEN

SUMMARY: To accelerate the development and future availability of safe, effective and affordable HIV vaccines it is essential to address not only the associated biomedical obstacles, but also the logistic aspects that would guide the introduction and use of those vaccines. It is likely that initial vaccines may only be partially effective, and their public health use will have to be carefully considered. This report summarizes the discussions from a consultation held in Geneva (20-21 November 2002) organized by the World Health Organization (WHO), the joint United Nations Programme on HIV/AIDS (UNAIDS) and the US Centers for Disease Control and Prevention (CDC). The group identified a number of logistic issues that need to be addressed to accelerate the development and future availability of HIV vaccines, and made broad recommendations in four different areas: (a) Vaccine manufacturing and licensing; (b) vaccination acceptability and social marketing; (c) immunisation strategies and delivery; and (d) access and economic issues. The implementation of these recommendations will require the participation of multiple stakeholders in the public and private sector, in industrialized and developing countries. These actions will be essential to ensure widespread and rapid access to HIV vaccines globally, soon after their efficacy is demonstrated in clinical trials.


Asunto(s)
Vacunas contra el SIDA/uso terapéutico , Infecciones por VIH/prevención & control , Salud Pública , Vacunas contra el SIDA/economía , Vacunas contra el SIDA/provisión & distribución , Síndrome de Inmunodeficiencia Adquirida/prevención & control , Ensayos Clínicos como Asunto , Industria Farmacéutica , Organización de la Financiación/métodos , Política de Salud , Accesibilidad a los Servicios de Salud , Humanos , Inmunización/métodos , Concesión de Licencias , Comercialización de los Servicios de Salud
12.
Curr Med Chem ; 8(7): 809-14, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11375751

RESUMEN

Parkinson's disease occurs in 1% of people over the age of 65 when about 60% of the dopaminergic neurons in the substantia nigra of the midbrain are lost. Dopaminergic neurons appear to die by a process of apoptosis that is induced by oxidative stress. Oxygen radicals abstract hydrogen from DNA forming DNA radicals that lead to DNA fragmentation, activation of DNA protective mechanisms, NAD depletion and apoptosis. Oxygen radicals can be formed in dopaminergic neurons by redox cycling of MPP+, the active metabolite of MPTP. This redox cycling mechanism involves the reduction of MPP+ by a number of enzymes, especially flavin containing enzymes, some of which are found in mitochondria. Tyrosine hydroxylase is present in all dopaminergic neurons and is responsible for the synthesis of dopamine. However, tyrosine hydroxylase can form oxygen radicals in a redox mechanism involving its cofactor, tetrahydrobiopterin. Dopamine may be oxidized by monoamine oxidase to form oxygen radicals and 3,4-dihydroxyphenylacetaldehyde. This aldehyde may be oxidized by aldehyde dehydrogenase with the formation of oxygen radicals and 3,4-dihydroxyphenylacetic acid. The redox mechanisms of oxygen radical formation by MPTP, tyrosine hydroxylase, monoamine oxidase and aldehyde dehydrogenase will be discussed. Possible clinical applications of these mechanisms will be briefly presented.


Asunto(s)
Aldehído Deshidrogenasa/metabolismo , Dopamina/metabolismo , Monoaminooxidasa/metabolismo , Enfermedad de Parkinson/metabolismo , Tirosina 3-Monooxigenasa/metabolismo , 1-Metil-4-fenil-1,2,3,6-Tetrahidropiridina/química , 1-Metil-4-fenil-1,2,3,6-Tetrahidropiridina/metabolismo , Animales , Humanos , Ratones , Oxidación-Reducción , Enfermedad de Parkinson/etiología
13.
Curr Med Chem ; 10(24): 2669-78, 2003 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-14529457

RESUMEN

Numerous pathophysiological disorders involve some element of oxidative stress and bioenergetic deficit. Poly(ADP-ribose) polymerase-1 (PARP-1) inhibitors have been used recently as a promising new therapeutic strategy aimed at halting the bioenergetic decline associated with oxidative brain insults and other conditions. PARP-1 uses NAD+ as a substrate and is activated during stressful circumstances, mainly in the nucleus. PARP-1 inhibitors are well known for blocking the excessive consumption of NAD+, thereby preserving energy metabolism. But what is the role of mitochondria in this process? Recent investigations have begun to focus on whether mitochondrial function can also be preserved by PARP-1 inhibitors. This review will present some of the latest mechanistic evidence documenting the potential involvement of PARP-1 inhibitors in protecting mitochondrial function and preventing necrosis, apoptosis and mitochondrial calcium cycling.


Asunto(s)
Apoptosis/efectos de los fármacos , Inhibidores Enzimáticos/uso terapéutico , Mitocondrias/metabolismo , NAD/metabolismo , Inhibidores de Poli(ADP-Ribosa) Polimerasas , Animales , Señalización del Calcio , Núcleo Celular/metabolismo , Humanos , Necrosis , Estrés Oxidativo , Poli(ADP-Ribosa) Polimerasas/metabolismo
14.
Curr Top Med Chem ; 1(6): 473-82, 2001 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11895124

RESUMEN

Oxidative stress occurs in the brain due to stroke, Parkinson's disease, Alzheimer's disease, amyotrophic lateral sclerosis, trauma, aging and other conditions. Analysis of the effects of oxidative stress can involve quantitation of brain GSH, GSSG, NADPH and NADP. Reliable and rapid assays have been developed for these compounds and will be presented in detail. The assays have been used to analyze the effects of brain oxidative stress. Thermodynamic calculations can be performed to find the observed electrochemical potentials of the GSSG/GSH and the NADP/NADPH couples during oxidative stress. The biochemical consequences of these thermodynamic changes in the cell will be discussed as well as the defense mechanisms available to the cell to recover from oxidative stress.


Asunto(s)
Encéfalo/metabolismo , Estrés Oxidativo , Animales , Encéfalo/anatomía & histología , Química Encefálica , Técnicas de Química Analítica , Glutatión/análisis , Glutatión/metabolismo , Humanos , NADP/análisis , NADP/metabolismo , Oxidación-Reducción , Termodinámica
15.
Ann N Y Acad Sci ; 786: 135-51, 1996 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-8687015

RESUMEN

DNA is a primary site of damage during oxidative stress in the brain. DNA fragmentation occurs within minutes of induction of oxidative stress. This DNA fragmentation probably results from the attack of free radicals on DNA and from the activation of endonucleases. Oxidative stress was induced by intracerebroventricular injection of t-butylhydroperoxide. This results in a very rapid flux of t-butylhydroperoxide, which is cleared from the brain within minutes. This flux of t-butylhydroperoxide results in the formation of hydroxyl radical in the brain and probably in the nuclei of brain cells. Necrosis results from extensive DNA fragmentation caused by massive oxidative stress. Cresyl violet stained brain sections demonstrated necrosis in many brain regions. In addition, previous electron microscopy studies showed degradation of cellular nuclei caused by tBuOOH toxicity. Low doses of t-butylhydroperoxide can induce apoptosis, which is a delayed form of cell death. Apoptosis was found in brains stained to visualize apoptotic DNA fragments. Experiments performed in mice aged 2, 8 or 24 months will be discussed. We have also found that apoptosis and DNA fragmentation can be prevented by pretreating mice with the vitamin micotinamide. Nicotinamide is a precursor for NAD. DNA repair requires high levels of NAD in the nucleus for the activity of poly(ADP-ribose) polymerase. Oxidative stress in the brain produces both necrosis and apoptosis, probably as the result of DNA fragmentation. Senescence is associated with an increase in the production of DNA fragments during brain oxidative stress, which probably leads to more necrosis and apoptosis than in younger mice.


Asunto(s)
Envejecimiento/metabolismo , Apoptosis , Encéfalo/metabolismo , Estrés Oxidativo , Animales , Corteza Cerebral/metabolismo , ADN/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Tálamo/metabolismo
16.
J Appl Physiol (1985) ; 78(1): 225-31, 1995 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-7713816

RESUMEN

Mepacrine, a cell membrane stabilizer and inhibitor of phospholipase A2 (PLA2), exerts a protective effect on ischemia-reperfusion injury in heart; however, its effect in lungs has not been examined. This study aimed to determine whether mepacrine pretreatment attenuates ischemia-reperfusion lung injury simulated by hypoxia reoxygenation and to identify possible mechanisms for such protection. Acute lung injury was induced in Sprague-Dawley rats by ventilation with 5% CO2-95% N2 and 5% CO2-95% air. Pretreatment with 0.06 mM mepacrine significantly attenuated the acute lung injury. Capillary filtration coefficient, lung weight gain, and protein concentration of lung lavage fluid were significantly lower in mepacrine-treated rats than in rats exposed to hypoxia reoxygenation alone. Steroid dexamethasone, another potential PLA2 inhibitor, had almost no protective effect. Mepacrine but not dexamethasone caused dose-dependent attenuation of the increase in leukocyte chemiluminescence produced by exposure to phorbol myristate acetate. Mepacrine also dose-dependently inhibited production of tumor necrosis factor-alpha (TNF-alpha) by human monocytes; dexamethasone was much less effective in decreasing TNF-alpha production. We conclude that mepacrine but not dexamethasone can significantly attenuate a hypoxia-reoxygenation-induced injury of the lung. This protective effect of mepacrine may not be the result of its inhibition of PLA2 but rather of its downregulation of oxygen radical production by circulating or resident leukocytes or its attenuation of TNF-alpha production by macrophages.


Asunto(s)
Hipoxia/fisiopatología , Enfermedades Pulmonares/prevención & control , Circulación Pulmonar/fisiología , Quinacrina/uso terapéutico , Daño por Reperfusión/prevención & control , Animales , Permeabilidad Capilar/efectos de los fármacos , Permeabilidad Capilar/fisiología , Dexametasona/farmacología , Granulocitos/efectos de los fármacos , Granulocitos/metabolismo , Granulocitos/fisiología , Técnicas In Vitro , Recuento de Leucocitos , Enfermedades Pulmonares/fisiopatología , Tamaño de los Órganos/efectos de los fármacos , Tamaño de los Órganos/fisiología , Perfusión , Fosfolipasas A/antagonistas & inhibidores , Fosfolipasas A2 , Presión Esfenoidal Pulmonar/efectos de los fármacos , Presión Esfenoidal Pulmonar/fisiología , Ratas , Ratas Sprague-Dawley , Daño por Reperfusión/fisiopatología , Factor de Necrosis Tumoral alfa/biosíntesis , Resistencia Vascular/efectos de los fármacos , Resistencia Vascular/fisiología
17.
Eur J Pharmacol ; 367(2-3): 389-98, 1999 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-10079015

RESUMEN

Tetrandrine, a purified traditional Chinese medicinal herb that acts as an immunosuppressant and a Ca2+ channel blocker, has been clinically used to treat patients with arthritis, silicosis and hypertension. Since T cells play a critical role as autoreactive and pathogenic population in autoimmune diseases, in this study, we examined the immunosuppressive effect of tetrandrine on human peripheral blood T cells. We showed that tetrandrine inhibited phorbol 12-myristate 13-acetate (PMA) + ionomycin-induced T cell proliferation, interleukin-2 secretion and the expression of the T cell activation antigen, CD71. Further investigation of the molecular mechanism demonstrated that tetrandrine inhibited the expression of the protein kinase C-dependent interleukin-2 receptor alpha chain and CD69 but not the expression of the Ca2+-dependent CD40 ligand and CD69. Interestingly, when tetrandrine and cyclosporin A were added together, significant synergism in the suppression of T cell activation was observed. Moreover, of the several tetrandrine analogues studied, hernandezine was the most potent inhibitor of protein kinase C signaling events. These results also suggest that the protein kinase C-inhibitory capacity of tetrandrine and its analogues may not be associated with their function as Ca2+ channel blockers. Lastly, we showed that, within therapeutic concentrations, tetrandrine and its analogues could induce cellular apoptosis, which is defective in autoimmune diseases. In conclusion, our findings provide novel information about the molecular mechanism of the immunosuppressive effect of tetrandrine and its analogues in human peripheral blood T cells.


Asunto(s)
Alcaloides/farmacología , Bencilisoquinolinas , Regulación hacia Abajo , Proteína Quinasa C/fisiología , Transducción de Señal/efectos de los fármacos , Linfocitos T/efectos de los fármacos , Antígenos/efectos de los fármacos , Antineoplásicos Fitogénicos , Bloqueadores de los Canales de Calcio/farmacología , División Celular , Ciclosporina/farmacología , Fragmentación del ADN , Sinergismo Farmacológico , Ensayo de Inmunoadsorción Enzimática , Humanos , Inmunosupresores/farmacología , Técnicas In Vitro , Interleucina-2/metabolismo , Ionomicina/farmacología , Receptores de Interleucina-2/efectos de los fármacos , Acetato de Tetradecanoilforbol/farmacología
18.
J Dent Res ; 80(12): 2055-9, 2001 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11808761

RESUMEN

Many cytokines have been thought to play important roles in the pathogenesis of oral submucous fibrosis (OSF), an areca nut chewing-specific pre-cancerous condition characterized by the deposition of collagen in oral submucosa. Tumor necrosis factor-alpha (TNF-alpha), situated in the class III region of human leukocyte antigen (HLA), is a mediator with multiple functions, including the regulation of inflammatory reaction and transcriptions of collagen and collagenase. In total, 809 male subjects were recruited for assessment of the association of OSF with a bi-allelic promoter-region (-308) polymorphism on the TNFA gene. The high production allele, TNF2, was significantly lower among OSF subjects (n = 166) than in areca-chewing controls (n = 284). This association was independent of oral cancer status. The multivariate-adjusted odds ratio for the TNFA 11 genotype was 2.6 (95% confidence interval = 1.4-4.9; p = 0.004). The finding may imply a multifunctional etiological factor of TNF-alpha in OSF pathogenesis.


Asunto(s)
Neoplasias de la Boca/genética , Fibrosis de la Submucosa Bucal/genética , Lesiones Precancerosas/genética , Factor de Necrosis Tumoral alfa/genética , Adulto , Factores de Edad , Areca/efectos adversos , Estudios de Casos y Controles , Etnicidad , Genotipo , Humanos , Modelos Logísticos , Masculino , Persona de Mediana Edad , Oportunidad Relativa , Fibrosis de la Submucosa Bucal/etiología , Polimorfismo de Longitud del Fragmento de Restricción , Factores de Riesgo , Encuestas y Cuestionarios , Taiwán
19.
Clin Rheumatol ; 18(2): 158-62, 1999.
Artículo en Inglés | MEDLINE | ID: mdl-10357123

RESUMEN

The aims of this study were to describe hormonal profiles, cytokine production and Fc-gamma receptor (Fcgamma-R) distribution in male lupus patients in Taiwan, and to look for any differences between our patients and normal individuals. Sixteen newly diagnosed and untreated male lupus patients were studied. Hormonal profiles were determined by radioimmunoassay. Interleukin-1 (IL-1) and IL-1 receptor antagonist (IL-1ra) production from both monocytes and neutrophils was determined by ELISA and murine thymocyte proliferation assay. The FcgammaR distribution on both monocytes and neutrophils was detected by flow cytometer. There were no significant differences in FSH, LH, testosterone, oestradiol, and beta-HCG blood levels in male lupus patients compared with normal individuals; however, the prolactin level in lupus patients was significantly higher than in normal individuals. Furthermore, there was no difference in IL-1 and IL-1ra production from both monocytes and neutrophils among male and female lupus patients, and normal individuals. Male lupus patients have a significantly lower FcgammaRII distribution on both monocytes and neutrophils when compared with female lupus patients and normal individuals. It was concluded that the high prolactin level and low FcgammaR distribution may play a role in the pathogenesis and prognosis of male lupus.


Asunto(s)
Hormonas Esteroides Gonadales/sangre , Interleucina-1/biosíntesis , Lupus Eritematoso Sistémico/inmunología , Receptores de IgG/metabolismo , Sialoglicoproteínas/biosíntesis , Adulto , China/etnología , Ensayo de Inmunoadsorción Enzimática , Femenino , Citometría de Flujo , Humanos , Proteína Antagonista del Receptor de Interleucina 1 , Lupus Eritematoso Sistémico/etnología , Activación de Linfocitos , Masculino , Persona de Mediana Edad , Monocitos/metabolismo , Neutrófilos/metabolismo , Radioinmunoensayo , Caracteres Sexuales , Taiwán/epidemiología
20.
J Formos Med Assoc ; 89(4): 326-30, 1990 Apr.
Artículo en Zh | MEDLINE | ID: mdl-1976752

RESUMEN

Antibodies to type II collagen (Col II) in sera and synovial fluid (SF) were measured with an enzyme linked immunosorbent assay (ELISA) using a solid phase sandwich method. The subjects included: 42 patients with rheumatoid arthritis (RA); 31 cases of osteoarthritis (OA); 10 cases of gouty arthritis; 4 cases of ankylosing spondylitis (AS); 5 cases of systemic lupus erythematosus (SLE); and 44 normal controls. The antigens used to detect antibodies against Col II were in native and heat-treated denatured forms, both of which were purified from chicken sternal cartilage by limited enzyme digestion and differential precipitation with salt. The reactivity to native type II collagen was generally higher than the reaction to the denatured collagen. In sera, significant higher levels of Col II were detected in the different arthritis groups when compared with the normal control group, with the exception of AS. In SF, the Col II was significantly higher in RA than it was in OA (p less than 0.001), while no difference was present between gout and OA (p less than 0.05). When native Col II was simultaneously measured in sera and SF among arthritics, positive rates were both higher among RA (65% and 58%, respectively). Positive rates were only higher in sera among OA (59% in sera and 3% in SF) and were both lower among gouty arthritis. The above findings show that the measurement of Col II is more important in SF than in sera.


Asunto(s)
Artritis Reumatoide/inmunología , Autoanticuerpos/sangre , Colágeno/inmunología , Líquido Sinovial/inmunología , China , Humanos
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