Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 27
Filtrar
Más filtros

País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Environ Sci Technol ; 47(12): 6564-72, 2013 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-23725041

RESUMEN

We present a dynamic model of global copper stocks and flows which allows a detailed analysis of recycling efficiencies, copper stocks in use, and dissipated and landfilled copper. The model is based on historical mining and refined copper production data (1910-2010) enhanced by a unique data set of recent global semifinished goods production and copper end-use sectors provided by the copper industry. To enable the consistency of the simulated copper life cycle in terms of a closed mass balance, particularly the matching of recycled metal flows to reported historical annual production data, a method was developed to estimate the yearly global collection rates of end-of-life (postconsumer) scrap. Based on this method, we provide estimates of 8 different recycling indicators over time. The main indicator for the efficiency of global copper recycling from end-of-life (EoL) scrap--the EoL recycling rate--was estimated to be 45% on average, ± 5% (one standard deviation) due to uncertainty and variability over time in the period 2000-2010. As uncertainties of specific input data--mainly concerning assumptions on end-use lifetimes and their distribution--are high, a sensitivity analysis with regard to the effect of uncertainties in the input data on the calculated recycling indicators was performed. The sensitivity analysis included a stochastic (Monte Carlo) uncertainty evaluation with 10(5) simulation runs.


Asunto(s)
Cobre , Modelos Teóricos , Método de Montecarlo , Reciclaje
2.
Prostate ; 70(11): 1211-21, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-20564423

RESUMEN

BACKGROUND: Phenoxodiol, a synthetic analog of Genistein, is being assessed in several clinical studies against a range of cancer types and was shown to have a good efficacy and safety profile. In this study we tested the effects of Phenoxodiol against prostate cancer cell lines. METHODS: Cell-cycle analysis, plasmatic membrane damage, clonogenic assay, comet assay, and Western blot methodologies were employed to assess the effects of Phenoxodiol on prostate cancer cell lines. An in vivo model confirmed the potential therapeutic efficacy of Phenoxodiol when administered orally to tumor bearing mice. RESULTS: Phenoxodiol treatment promoted a marked inhibition of proliferation and loss of colony formation in LNCaP cells in a dose- and time-dependent manner. Similar effects were also observed in the metastatic prostate cell lines PC3 and DU145. Activation of poly(ADP ribose) polymerase 1 (PARP-1) clearly indicates the induction of DNA damage by Phenoxodiol. Oral administration of Phenoxodiol induced a considerable growth inhibition of malignant tumors generated by inoculation of LNCaP cells into Balb/c nu/nu athymic mice. CONCLUSIONS: These data demonstrated that Phenoxodiol promotes apoptosis, as determined by PARP-1 degradation, via mitochondrial depolarization and G1/S cell-cycle arrest thereby confirming that it is active against androgen-dependent and independent prostate cancer cells. Although a precise target for Phenoxodiol has not been identified, these data contribute to our understanding of the mechanism by which this drug promotes cell death in prostate cancer cells, and warrants the continued clinical development of Phenoxodiol as a therapeutic for the treatment of metastatic prostate cancer.


Asunto(s)
Isoflavonas/farmacología , Neoplasias de la Próstata/tratamiento farmacológico , Neoplasias de la Próstata/patología , Animales , Apoptosis/efectos de los fármacos , Ciclo Celular/efectos de los fármacos , Procesos de Crecimiento Celular/efectos de los fármacos , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Ensayo Cometa , Daño del ADN , Humanos , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Neoplasias Hormono-Dependientes/tratamiento farmacológico , Neoplasias Hormono-Dependientes/genética , Neoplasias Hormono-Dependientes/metabolismo , Neoplasias Hormono-Dependientes/patología , Poli(ADP-Ribosa) Polimerasa-1 , Inhibidores de Poli(ADP-Ribosa) Polimerasas , Poli(ADP-Ribosa) Polimerasas/metabolismo , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/metabolismo , Ensayos Antitumor por Modelo de Xenoinjerto
3.
Clin Infect Dis ; 49(9): 1305-11, 2009 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-19807276

RESUMEN

BACKGROUND: Human immunodeficiency virus (HIV)-associated tuberculosis is difficult to treat, given the propensity for drug interactions between the rifamycins and the antiretroviral drugs. We examined the pharmacokinetics of rifabutin before and after the addition of lopinavir-ritonavir. METHODS: We analyzed 10 patients with HIV infection and active tuberculosis in a state tuberculosis hospital. Plasma was collected for measurement of rifabutin, the microbiologically active 25-desacetyl-rifabutin, and lopinavir by validated high-performance liquid chromatography assays. Samples were collected 2-4 weeks after starting rifabutin at 300 mg thrice weekly without lopinavir-ritonavir, 2 weeks after the addition of lopinavir-ritonavir at 400 and 100 mg, respectively, twice daily to rifabutin at 150 mg thrice weekly, and (if rifabutin plasma concentrations were below the normal range) 2 weeks after an increase in rifabutin to 300 mg thrice weekly with lopinavir-ritonavir. Noncompartmental and population pharmacokinetic analyses (2-compartment open model) were performed. RESULTS: Rifabutin at 300 mg without lopinavir-ritonavir produced a low maximum plasma concentration (C(max)) in 5 of 10 patients. After the addition of lopinavir-ritonavir to rifabutin at 150 mg, 9 of 10 had low C(max) values. Eight patients had dose increases to 300 mg of rifabutin with lopinavir-ritonavir. Most free rifabutin (unbound to plasma protein) C(max) values were below the tuberculosis minimal inhibitory concentration. For most patients, values for the area under the plasma concentration-time curve were as low or lower than those associated with treatment failure or relapse and with acquired rifamycin resistance in Tuberculosis Trials Consortium/US Public Health Service Study 23. One of the 10 patients experienced relapse with acquired rifamycin resistance. CONCLUSION: The recommended rifabutin doses for use with lopinavir-ritonavir may be inadequate in many patients. Monitoring of plasma concentrations is recommended.


Asunto(s)
Antibióticos Antituberculosos/farmacocinética , Antivirales/farmacocinética , Infecciones por VIH/complicaciones , Infecciones por VIH/tratamiento farmacológico , Pirimidinonas/farmacocinética , Rifabutina/farmacocinética , Ritonavir/farmacocinética , Tuberculosis/complicaciones , Tuberculosis/tratamiento farmacológico , Adulto , Antibióticos Antituberculosos/sangre , Antibióticos Antituberculosos/uso terapéutico , Antivirales/sangre , Antivirales/uso terapéutico , Interacciones Farmacológicas , Femenino , Humanos , Lopinavir , Masculino , Persona de Mediana Edad , Pirimidinonas/sangre , Pirimidinonas/uso terapéutico , Rifabutina/sangre , Rifabutina/uso terapéutico , Ritonavir/sangre , Ritonavir/uso terapéutico
4.
An. Fac. Med. (Perú) ; 85(1): 92-96, ene.-mar. 2024. tab
Artículo en Español | LILACS-Express | LILACS | ID: biblio-1556808

RESUMEN

RESUMEN Presentamos la experiencia del Policlínico de la Peruvian American Medical Society (PAMS) en Chincha, en la ejecución de misiones médico-educativas en la región Chincha. El Policlínico PAMS presta atención médica general y especializada a la población de la zona, seis días a la semana. Además, recibe misiones médicas que vienen generalmente de los EE. UU. Desde 2011, se han recibido 43 misiones médicas. La composición y la naturaleza de las misiones han cambiado con el tiempo. Los primeros años se atraía a especialistas con el énfasis de traer equipos e insumos para mejorar la infraestructura del Policlínico. Ahora estamos limitados por la renuencia de voluntarios de venir al Perú en parte debido a que el gobierno americano considera que viajes al Perú son de alto riesgo. Esta limitación nos ha brindado la oportunidad de hacer misiones médicas juntamente con dos excelentes universidades peruanas. La experiencia ha sido positiva.


ABSTRACT We present the experience of the Polyclinic of the Peruvian American Medical Society (PAMS) in Chincha, in the execution of medical educational missions in the Chincha region. The PAMS Polyclinic provides general and specialized medical care to the population of the area, six days a week. In addition, the Polyclinic receives medical missions generally coming from the EE.UU. Since 2011, we have received 43 medical missions. The composition and nature of the missions have changed over time. The first years attracted specialists with the emphasis on bringing equipment and supplies to improve the infrastructure of the Polyclinic. We are now limited by the reluctance of volunteers to come to Peru in part because the U.S. government considers travel to Peru to be high-risk. This limitation has given us the opportunity to do medical missions together with two excellent Peruvian universities. This experience has been positive.

5.
Cell Signal ; 19(4): 867-79, 2007 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-17196367

RESUMEN

Protein kinase D localizes in the Golgi and regulates protein transport from the Golgi to the plasma membrane. In the present study, we found that PKD3, a novel member of the PKD family, and its fluorescent protein fusions localized in the Golgi and in the vesicular structures that are in part marked by endosome markers. Fluorescent recovery after photobleaching (FRAP) showed that the PKD3-associated vesicular structures were constantly forming and dissolving, reflecting active subcellular structures. FRAP on plasma membrane-located PKD3 indicated a slower recovery of PKD3 fluorescent signal compared to those of PKC isoforms, implying a different targeting mechanism at the plasma membrane. VAMP2, the vesicle-localized v-SNARE, was later identified as a novel binding partner of PKD3 through yeast two-hybrid screening. PKD3 directly interacted with VAMP2 in vitro and in vivo, and colocalized in part with VAMP2 vesicles in cells. PKD3 did not phosphorylate VAMP-GFP and the purified GST-VAMP2 protein in in vitro phosphorylation assays. Rather, PKD3 was found to promote the recruitment of VAMP2 vesicles to the plasma membrane in response to PMA, while the kinase dead PKD3 abolished this effect. Thus, the kinase activity of PKD3 was required for PMA-induced plasma membrane trafficking of VAMP2. In summary, our findings suggest that PKD3 localizes to vesicular structures that are part of the endocytic compartment. The vesicular distribution may be attributed in part to the direct interaction between PKD3 and vesicle-associated membrane protein VAMP2, through which PKD3 may regulate VAMP2 vesicle trafficking by facilitating its recruitment to the target membrane.


Asunto(s)
Vesículas Citoplasmáticas/enzimología , Proteína Quinasa C/metabolismo , Proteína 2 de Membrana Asociada a Vesículas/metabolismo , Animales , Células CHO , Membrana Celular/enzimología , Cricetinae , Cricetulus , Citosol/enzimología , Endosomas/enzimología , Aparato de Golgi/enzimología , Humanos , Fosforilación , Unión Proteica , Transporte de Proteínas , Proteínas Recombinantes de Fusión/metabolismo
6.
Water Res ; 42(6-7): 1778-84, 2008 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-18036632

RESUMEN

We report the irradiation of TiO(2) suspensions containing Br(-) and dissolved organic carbon (DOC). In the absence of DOC, we found no evidence for the formation of BrO(3)(-) upon irradiation of 1gL(-1) P25 suspensions with UV light for initial Br(-) concentrations up to 10mgL(-1). In the presence of DOC (Lake Hohloh, Germany and salicylic acid), we found no evidence for the formation of either BrO(3)(-) or trihalomethanes (THMs). However, small amounts of adsorbable organic halogen (AOX) were formed at high bromide concentrations (3mgL(-1)). When irradiating P25 suspensions containing bromide and 2,4-dihydroxybenzoic acid (DHBA, high bromoform formation potential), we observed the formation of significant amounts of bromoform (up to 10microgL(-1)). Bromoform appeared only after the DHBA had been degraded.


Asunto(s)
Bromo/química , Carbono/química , Titanio/química , Cromatografía Liquida , Solubilidad
7.
J Clin Exp Dent ; 10(2): e134-e138, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29670730

RESUMEN

BACKGROUND: Dental caries is a multifactorial disease that affects the general population. After reviewing the scientific literature, no studies were found on the index of decayed, missing and filled teeth (DMFT) in the Peruvian police population. The objective was to evaluate the DMFT index and severity level of the disease in police personnel of the Ancash region, Peru. MATERIAL AND METHODS: Cross-sectional prevalence study. The medical records of the police personnel in activity were reviewed and each subject was examined from May 2012 to May 2013. The study was authorized by the Director of the PNP-Huaraz Ancash Polyclinic as part of the activities of the civil SERUMS personnel in the area of odontology. The sample was census with 925 subjects. The data was systematized following the methodology recommended by the World Health Organization (WHO). The statistics were analyzed by Chi square test with significance p<0.05, Pearson test and ANOVA. RESULTS: The prevalence of caries in the police population was 73.4%. The DMFT index was 10.63 ± 4.96 (p<0.01). The severity of the disease in relation to age was 0.77 ± 0.41 with a high risk in this population. The DMFT index in females 128/925 and males 797/925 was 10.43 and 10.67 respectively. There is an inversely proportional relationship in the number of teeth filled with dental amalgam in policemen older than 35 years versus the number of teeth sealed with material other than dental amalgam in policemen under 35 years. Only 0.8% 7/925 had dental prostheses and 58.6% (542/925) of the subjects needed oral rehabilitation. CONCLUSIONS: The severity of dental caries is high, strategies are required to improve intervention in this sector, developing effective programs in oral health in the short, medium and long term. Key words:Dental caries severity, oral health, dental caries prevalence, peruvian police.

8.
An. Fac. Med. (Perú) ; 84(1)mar. 2023.
Artículo en Español | LILACS-Express | LILACS | ID: biblio-1439167

RESUMEN

La pandemia del COVID-19 tuvo un impacto significativo en el cuidado y la educación médicos en el Perú. En respuesta, la Sociedad Médica Peruano Americana (PAMS), una organización médica benéfica con sede en los EE.UU., adoptó sus misiones médicas y educativas en Perú usando estrategias virtuales. Desarrollamos colaboración con varias facultades de medicina y la Asociación Peruana de Facultades de Medicina (ASPEFAM) y ofrecimos un panel de veinte y cuatro miembros para brindar conferencias y seminarios multidisciplinarios en español. Hicimos 19 seminarios, incluyendo temas relacionados y no relacionados al COVID-19, que en los últimos dos años atrajo a 14 489 participantes de 23 países. Ellas fueron la base de 20 publicaciones en revistas médicas peruanas. Nuestro concurso de investigaciones clínicas y nuestro proyecto piloto de mentoría de investigación fueron recibidos positivamente. La pandemia del COVID-19 tuvo un efecto positivo en la misión educativa de PAMS en Perú.


The COVID-19 pandemic had a significant impact on medical care and medical education in Peru. In response, the Peruvian American Medical Society (PAMS), a charitable medical organization based in the USA, pursued its medical and educational missions in Peru by adopting virtual learning technology. We developed closer collaborative relationships with several medical schools and the Peruvian Association of Medical Schools (ASPEFAM) while offering a faculty panel of twenty-four members to provide lectures and multidisciplinary webinars in Spanish. We conducted 19 webinars including COVID -19 and non-COVID-19 related topics that over the last two years attracted 14,489 participants from 23 countries. They were the foundation for twenty publications in Peruvian medical journals. Our clinical investigations competition was positively received as was our pilot project on research mentorship. The COVID -19 pandemic had a positive effect on the educational mission of PAMS in Peru.

9.
Free Radic Biol Med ; 42(9): 1430-40, 2007 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-17395016

RESUMEN

Environmental pollutants inducing oxidative stress stimulate chronic inflammatory responses in the lung leading to pulmonary tissue dysfunction. In response to oxidative stress, alveolar macrophages produce both reactive oxygen species and reactive nitrogen species, which induce the expression of a wide variety of immune-response genes. We found that a prolonged exposure of alveolar macrophages to a nonlethal dose (8 microg/ml) of JP-8, the kerosene-based hydrocarbon jet fuel, induced the persistent expression of IL-1, iNOS, and COX-2, as well as cell adhesion molecules (ICAM-1 and VCAM-1). Because poly(ADP-ribose) polymerase (PARP-1), a coactivator of NF-kappaB, regulates inflammatory responses and associated disorders in the airways, we determined whether JP-8 induces the poly(ADP-ribosyl)ation automodification of PARP-1 in alveolar macrophages. We observed that PARP-1 is activated in a time-dependent manner, which was temporally coincident with the prolonged activation of NF-kappaB and with the augmented expression of the proinflammatory factors described above. The 4 microg/ml dilution of JP-8 also increased the activity of PARP-1 as well as the expression of iNOS and COX-2, indicating that lower doses of JP-8 also affect the regulation of proinflammatory factors in pulmonary macrophages. Together, these results demonstrate that an extensive induction of PARP-1 might coordinate the persistent expression of proinflammatory mediators in alveolar macrophages activated by aromatic hydrocarbons that can result in lung injury from occupational exposure.


Asunto(s)
Citocinas/genética , Contaminantes Ambientales , Hidrocarburos/toxicidad , Macrófagos Alveolares/fisiología , Poli(ADP-Ribosa) Polimerasas/metabolismo , Animales , Línea Celular , Medios de Cultivo , Combustibles Fósiles/toxicidad , Glutatión/metabolismo , Modelos Animales , Exposición Profesional , Ácido Peroxinitroso/metabolismo , Poli(ADP-Ribosa) Polimerasas/genética , Ratas , Especies Reactivas de Oxígeno/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
10.
Water Res ; 41(19): 4479-87, 2007 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-17659318

RESUMEN

The photoinitiated degradation of bisphenol A (BPA, 520 micromol/L) was investigated using a solar simulator in the absence/presence of NO(3)(-), Fe(III), and HCO(3)(-). The concentrations of NO(3)(-), Fe(III), and HCO(3)(-) were 0-160, 0-10, and 0-820 micromol/L, respectively, and were chosen to simulate a natural aquatic environment. The experimental region was explored using a Box-Behnken design for three factors, extended to experimentally include all eight possible combinations of presence/absence of the factors studied. The results show that, after 7h of irradiation, photolysis occurs only to a minimal degree (2%) in the absence of NO(3)(-) and HCO(3)(-). Increasing the concentration of NO(3)(-) and HCO(3)(-) gives rise to up to 24% degradation after 7h of irradiation. The concentration of Fe(III) was found to play no active role under the conditions studied. A simple linear model is given that very well describes the results obtained.


Asunto(s)
Bicarbonatos/química , Compuestos Férricos/química , Nitratos/química , Fenoles/química , Compuestos de Bencidrilo , Cromatografía Líquida de Alta Presión , Rayos Ultravioleta
11.
AIDS Read ; 17(8): 402-4, 2007 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-17717884

RESUMEN

Acute mastoiditis, an infectious inflammatory process in the temporal bone, is an uncommon complication of otitis media. Here we describe a fatal case of mastoiditis complicated by thrombosis of the sigmoid sinus and intracerebral abscess caused by an unusual pathogen (Nocardia asteroides) in a person with HIV infection. Sulfonamides have remained the first-line agents for the management of Nocardia infections, but mortality remains high in patients with intracerebral infection.


Asunto(s)
Infecciones Oportunistas Relacionadas con el SIDA/microbiología , Absceso Encefálico/microbiología , Infecciones por VIH/complicaciones , Mastoiditis/complicaciones , Infecciones Oportunistas Relacionadas con el SIDA/tratamiento farmacológico , Infecciones Oportunistas Relacionadas con el SIDA/patología , Adulto , Senos Craneales/patología , Resultado Fatal , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/microbiología , Infecciones por VIH/patología , Cabeza/diagnóstico por imagen , Humanos , Masculino , Mastoiditis/microbiología , Mastoiditis/patología , Nocardia asteroides/aislamiento & purificación , Radiografía , Trombosis de los Senos Intracraneales
12.
Oncogene ; 22(52): 8460-71, 2003 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-14627987

RESUMEN

The transcription factor E2F-1 is implicated in the activation of S-phase genes as well as induction of apoptosis, and is regulated by interactions with Rb and by cell cycle-dependent alterations in E2F-1 abundance. We earlier demonstrated a pivotal role for poly(ADP-ribose) polymerase-1 (PARP-1) in the regulation of E2F-1 expression and promoter activity during S-phase re-entry when quiescent cells re-enter the cell cycle. We now investigate the putative mechanism(s) by which PARP-1 may upregulate E2F-1 promoter activity during S-phase re-entry. DNase-1 footprint assays with purified PARP-1 showed that PARP-1 did not directly bind the E2F-1 promoter in a sequence-specific manner. In contrast to p53, a positive acceptor in poly(ADP-ribosyl)ation reactions, E2F-1 was not poly(ADP-ribosyl)ated by wild-type PARP-1 in vitro, indicating that PARP-1 does not exert a dual effect on E2F-1 transcriptional activation. Protein-binding reactions and coimmunoprecipitation experiments with purified PARP-1 and E2F-1, however, revealed that PARP-1 binds to E2F-1 in vitro. More significantly, physical association of PARP-1 and E2F-1 in vivo also occurred in wild-type fibroblasts 5 h after re-entry into S phase, coincident with the increase in E2F-1 promoter activity and expression of E2F-1-responsive S-phase genes cyclin A and c-Myc. Mapping of the interaction domains revealed that full-length PARP-1 as well as PARP-1 mutants lacking either the catalytic active site or the DNA-binding domain equally bind E2F-1, whereas a PARP-1 mutant lacking the automodification domain does not, suggesting that the protein interaction site is located in this central domain. Finally, gel shift analysis with end-blocked E2F-1 promoter sequence probes verified that the binding of PARP-1 to E2F-1 enhances binding to the E2F-1 promoter, indicating that PARP-1 acts as a positive cofactor of E2F-1-mediated transcription.


Asunto(s)
Proteínas de Ciclo Celular , Proteínas de Unión al ADN , Poli(ADP-Ribosa) Polimerasas/metabolismo , Fase S/fisiología , Factores de Transcripción/metabolismo , Transcripción Genética , Animales , Sitios de Unión , Ciclina A/metabolismo , Factores de Transcripción E2F , Factor de Transcripción E2F1 , Genes myc/fisiología , Humanos , Pruebas de Precipitina
13.
J AIDS Clin Res ; 6(7)2015.
Artículo en Inglés | MEDLINE | ID: mdl-30627475

RESUMEN

INTRODUCTION: Hispanic adolescents domiciling in Florida rank second in the U.S. with respect to HIV/AIDS incidence and prevalence. Extending studies showing that risky sexual behavior is associated with limited access to information, this project surveyed knowledge about HIV etiology, prevention and treatment. METHODS: The sample consisted of 400 Hispanic youth between 11-18 years of age living in Miami, Florida. The sample is enrolled in an ongoing project Role of Brain Derived Neurotrophic Factor in Decision Making (ROBIM). The HIV Knowledge Questionnaire (HIV-KQ-18), an 18 item self-administered questionnaire was used to measure HIV knowledge, particularly transmission and prevention. RESULTS: Less than 10% of the sample had comprehensive knowledge about HIV/AIDS. Approximately 25% incorrectly answered all of the questions. Questions pertaining to transmission were incorrectly answered by more than half of the sample. The most frequent topics reflecting absence of knowledge are related to high-risk sexual behaviors (sex during the menses) and infection prevention methods (e.g. condoms). A majority of youth believed incorrectly that HIV could be cured (61%), an effective vaccine is available (61%), and antibiotics protect against HIV infection (76%). School (28%) and parents (26%) were the most frequent sources of knowledge about HIV/AIDS. However, youth receiving information from parents had significantly higher knowledge scores than peers receiving education in school (7.4 ± 4.15 vs. 6.1 ± 4.5 scores, p = 0.037). Yet, 68% of the sample had never discussed condom use with their parents. CONCLUSIONS: These findings indicate Hispanic youths, although at very high risk, are poorly informed about prevention of HIV/AIDS. Moreover, the most frequent source of information, namely schools, inculcates less knowledge than parents. Lastly, youths who discuss sex with parents do not typically dialog about condoms, the most readily available protection from HIV/AIDS. These findings identify gaps that need to be addressed for lowering the high rate of HIV infection in Hispanic youths.

14.
Br J Pharmacol ; 141(5): 795-802, 2004 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-14769780

RESUMEN

1. The mechanism of toxicity of sulphur mustard was investigated by examining the biochemical effects of the analog 2-chloroethylethyl sulphide (CEES) in both human Jurkat cells as well as normal human lymphocytes. 2. Exposure of both types of cells to CEES resulted in a marked decrease in the intracellular concentration of the reduced form of glutathione (GSH), and CEES-induced cell death was potentiated by l-buthionine sulphoximine, an inhibitor of GSH synthesis. 3. CEES increased the endogenous production of reactive oxygen species (ROS) in Jurkat cells, and CEES-induced cell death was potentiated by hydrogen peroxide. 4. CEES induced various hallmarks of apoptosis, including collapse of the mitochondrial membrane potential, proteolytic processing and activation of procaspase-3, and cleavage of poly (ADP-ribose) polymerase. 5. The effects of CEES on the accumulation of ROS, the intracellular concentration of GSH, the mitochondrial membrane potential, and caspase-3 activity were all inhibited by pretreatment of cells with the GSH precursor N-acetyl cysteine or with GSH-ethyl ester. Furthermore, CEES-induced cell death was also prevented by these antioxidants. 6. CEES toxicity appears to be mediated, at least in part, by the generation of ROS and consequent depletion of GSH. Given that sulphur mustard is still a potential biohazard, the protective effects of antioxidants against CEES toxicity demonstrated in Jurkat cells and normal human lymphocytes may provide the basis for the development of a therapeutic strategy to counteract exposure to this chemical weapon.


Asunto(s)
Antioxidantes/farmacología , Apoptosis/efectos de los fármacos , Linfocitos/efectos de los fármacos , Gas Mostaza/análogos & derivados , Gas Mostaza/toxicidad , Apoptosis/fisiología , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/fisiología , Humanos , Células Jurkat , Linfocitos/metabolismo , Especies Reactivas de Oxígeno/metabolismo
15.
Cancer Lett ; 212(1): 33-41, 2004 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-15246559

RESUMEN

We determined whether alterations in the expression of p53, p16(INK4) and p21(WAF1/CIP1) influence the invasiveness of a subset of gastric adenocarcinomas co-expressing TGFalpha and EGFR. Immunopositivity for TGFalpha-EGFR (26%) was observed in both early and advanced adenocarcinomas, and 88% of these showed immunoreactivity for p53. SSCP analysis revealed that in 81% of these tumors the p53 gene was mutated in exons 5-8. The intensity of p53 immunoreactivity was significantly higher (P < 0.013) in deeply invasive tumors. p16(INK4) and p21(WAF1/CIP1) immunoreactivity was detected in 93 and 76% of the samples co-expressing TGFalpha-EGFR but the levels were not correlated with those of p53 and other clinico-pathological parameters. We conclude that gastric adenocarcinomas potentially dependent upon the TGFalpha-EGFR autocrine loop for growing exhibit increased aggressiveness in the presence of aberrant p53.


Asunto(s)
Adenocarcinoma/genética , Adenocarcinoma/patología , Receptores ErbB/biosíntesis , Genes p53 , Invasividad Neoplásica , Neoplasias Gástricas/genética , Neoplasias Gástricas/patología , Factor de Crecimiento Transformador alfa/biosíntesis , Inhibidor p16 de la Quinasa Dependiente de Ciclina/biosíntesis , Inhibidor p16 de la Quinasa Dependiente de Ciclina/farmacología , Inhibidor p21 de las Quinasas Dependientes de la Ciclina , Ciclinas/biosíntesis , Ciclinas/farmacología , Análisis Mutacional de ADN , Inhibidores Enzimáticos/farmacología , Humanos , Inmunohistoquímica , Transducción de Señal
16.
Toxicology ; 189(3): 181-90, 2003 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-12832151

RESUMEN

The jet fuel JP-8 is widely used and a large number of military and civilian personnel is, therefore, exposed to it. Treatment of several cell lines, including human Jurkat cells, with JP-8 induces cell death that exhibits various biochemical and morphological characteristics of apoptosis. The molecular mechanism of JP-8 cytotoxicity, however, has remained unclear. The effects of exposure of Jurkat cells to JP-8 (1/10,000 dilution) for 4 h on gene expression have now been examined by cDNA macroarray analysis. We had previously shown in these cells that under the above conditions, JP-8 causes significant apoptosis, based upon the observation that caspase-3 activation occurs at approximately 4 h and consequently most of the other classical apoptotic biochemical and morphological alterations progress until apoptotic cell death at 24 h. Of the 439 apoptosis- or stress response-related genes examined, the expression of 16 genes was up-regulated and that of ten genes was down-regulated by a factor of > or =2. The changes in the expression of 11 of these 26 genes were confirmed by reverse transcription and polymerase chain reaction analysis. These results provide insight into the mechanism of JP-8 toxicity and the associated induction of apoptosis.


Asunto(s)
Regulación de la Expresión Génica/efectos de los fármacos , Hidrocarburos/toxicidad , Apoptosis/efectos de los fármacos , Caspasa 3 , Caspasas/metabolismo , Humanos , Células Jurkat/efectos de los fármacos , Células Jurkat/fisiología , Análisis de Secuencia por Matrices de Oligonucleótidos , ARN/química , ARN/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
17.
Clin Cancer Res ; 20(21): 5446-55, 2014 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-25208882

RESUMEN

PURPOSE: High levels of BCL-2 family members in colorectal carcinoma cause resistance to treatment. Inhibition of NANOG or its paralog NANOGP8 reduces the proliferation, stemness, and tumorigenicity of colorectal carcinoma cells. Our hypothesis was that inhibition of NANOG/NANOGP8 enhances the cytotoxic effect of BH3 mimetics targeting BCL-2 family members in colorectal carcinoma cells through reducing expression of MCL-1, a prosurvival BCL-2 protein. EXPERIMENTAL DESIGN: Lentiviral vector (LV) shRNA to NANOG (shNG-1) or NANOGP8 (shNp8-1) transduced colorectal carcinoma cells that were also exposed to the BH3 mimetics ABT-737 or ABT-199 in vivo in colorectal carcinoma xenografts and in vitro where proliferation, protein and gene expression, and apoptosis were measured. RESULTS: Clone A and CX-1 were sensitive to ABT-737 and ABT-199 at IC50s of 2 to 9 µmol/L but LS174T was resistant with IC50s of 18 to 30 µmol/L. Resistance was associated with high MCL-1 expression in LS174T. LVshNG-1 or LVshNp8-1 decreased MCL-1 expression, increased apoptosis, and decreased replating efficiency in colorectal carcinoma cells treated with either ABT-737 or ABT-199 compared with the effects of either BH3 mimetic alone. Inhibition or overexpression of MCL-1 alone replicated the effects of LVshNG-1 or LVshNp8-1 in increasing or decreasing the apoptosis caused with the BH3 mimetic. The combination therapy inhibited the growth of LS174T xenografts in vivo compared with untreated controls or treatment with only LV shRNA or ABT-737. CONCLUSIONS: Inhibition of NANOGP8 or NANOG enhances the cytotoxicity of BH3 mimetics that target BCL-2 family members. Gene therapy targeting the NANOGs may increase the efficacy of BH3 mimetics in colorectal carcinoma.


Asunto(s)
Proteína Proapoptótica que Interacciona Mediante Dominios BH3/genética , Neoplasias Colorrectales/genética , Regulación hacia Abajo/genética , Proteínas de Homeodominio/antagonistas & inhibidores , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/genética , Animales , Apoptosis/efectos de los fármacos , Apoptosis/genética , Compuestos de Bifenilo/farmacología , Compuestos Bicíclicos Heterocíclicos con Puentes/farmacología , Línea Celular , Línea Celular Tumoral , Neoplasias Colorrectales/tratamiento farmacológico , Regulación hacia Abajo/efectos de los fármacos , Células HEK293 , Células HT29 , Humanos , Masculino , Ratones , Ratones Endogámicos NOD , Ratones SCID , Proteína Homeótica Nanog , Nitrofenoles/farmacología , Piperazinas/farmacología , ARN Interferente Pequeño/genética , Sulfonamidas/farmacología , Ensayos Antitumor por Modelo de Xenoinjerto
18.
Water Res ; 45(3): 1039-48, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21093013

RESUMEN

Herein we report the photocatalytic degradation of natural organic matter from a bog lake (Lake Hohloh, Black Forest, Germany) in the presence of 0, 5, and 10 µmol L(-1) of added Cu(2+), Mn(2+), Zn(2+) and Fe(3+). The reactions were followed by size exclusion chromatography with organic carbon detection (SEC-DOC) and by measurements of low molecular weight organic acids. Addition of Cu(2+) had the largest effect of all four studied metals, leading to a retardation in the molecular size changes in NOM: degradation of the larger molecular weight fraction was inhibited leading to reduced production of smaller molecular weight metabolites. Similarly, addition of Cu(2+) reduced the production of formic and oxalic acids, and reduced the bioavailability of the partially degraded NOM.


Asunto(s)
Ácidos/química , Metales/química , Compuestos Orgánicos/química , Fotoquímica , Cromatografía en Gel , Cromatografía por Intercambio Iónico , Cobre/química , Iones/química , Manganeso/química , Peso Molecular , Aguas del Alcantarillado/microbiología , Zinc/química
19.
Water Res ; 43(16): 3902-9, 2009 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-19524280

RESUMEN

The degradation of natural organic matter (NOM) in homogeneous and heterogeneous advanced oxidation processes (AOP) was simulated using a simple underlying physical model. By treating the NOM molecules as linear chains and allowing them to be cleaved at any point selected at random, it is possible to reproduce well the results for homogeneous AOP experiments. To simulate a heterogeneous process, a bias was introduced (in the form of different weights for different chain lengths) according to literature data on the adsorption of NOM onto TiO(2) nanoparticle agglomerates. After introduction of the (adsorption) bias, the simulation closely followed the degradation sequence observed in heterogeneous photocatalysis with TiO(2) suspensions. Thus, the experimental results for homogeneous AOP may well be explained by a random breakdown of the NOM molecules; that is, we find no evidence for a selective degradation of the large molecular size material. However, a selectivity is present in the heterogeneous system due to the differential adsorption of NOM onto the reactive surface.


Asunto(s)
Modelos Químicos , Eliminación de Residuos/métodos , Carbono/análisis , Peróxido de Hidrógeno , Cinética , Oxidación-Reducción , Fotólisis , Titanio , Rayos Ultravioleta
20.
Water Res ; 43(17): 4143-8, 2009 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-19628249

RESUMEN

We report the formation of bromoform in TiO(2) suspensions (P25) under simulated solar UV irradiation at different concentrations of photocatalyst (0.5-1.5 g L(-1)) as well as initial concentrations of bromide ions (1-3mg L(-1)) and 2,4-dihydroxybenzoic acid (2-10mg L(-1)). The extent of bromoform formation (3-17microg L(-1)) was most strongly affected by the amount of photocatalyst present and by the initial bromide concentration, increasing either of which leads to increased bromoform formation. Important interaction effects were observed when simultaneously increasing the concentrations of TiO(2) and bromide as well as of bromide and DHBA. The time it takes for bromoform to appear in measurable concentrations in the irradiated TiO(2) suspensions was between 10 and 90 min and most strongly depended on the initial concentration of dissolved organic carbon present in the suspensions, along with the amount of photocatalyst, also in interaction with the initial bromide concentration.


Asunto(s)
Bromuros/análisis , Carbono/análisis , Fotoquímica , Titanio/química , Catálisis , Hidroxibenzoatos/química , Solubilidad , Trihalometanos/síntesis química
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA