RESUMEN
Millions of dollars have been spent on the design and dissemination of educational materials to improve handwashing to prevent infectious diseases. School-age children have been the focus of many of these efforts; yet little is known about the content of these materials. This study uses content analysis to examine the theoretical and motivational trends as well as the communication approach used in a sample of hand hygiene intervention materials targeting elementary-age children. Two trained coders analyzed 144 communication materials. Study results indicate that educational materials infrequently exhibit information consistent with theories of communication for behavior change, commonly use fear-based messaging, and rarely recommend using technology in the design of the interventions. Implications for future research and the design of more strategic, child-focused hand hygiene interventions are discussed.
Asunto(s)
Higiene de las Manos/métodos , Educación en Salud/métodos , Educación en Salud/estadística & datos numéricos , Niño , Preescolar , Comunicación , Miedo , Femenino , Desinfección de las Manos/métodos , Conocimientos, Actitudes y Práctica en Salud , Humanos , Masculino , Motivación , Estados UnidosRESUMEN
The International Society for Computational Biology, ISCB, organizes the largest event in the field of computational biology and bioinformatics, namely the annual international conference on Intelligent Systems for Molecular Biology, the ISMB. This year at ISMB 2012 in Long Beach, ISCB celebrated the 20th anniversary of its flagship meeting. ISCB is a young, lean and efficient society that aspires to make a significant impact with only limited resources. Many constraints make the choice of venues for ISMB a tough challenge. Here, we describe those challenges and invite the contribution of ideas for solutions.
Asunto(s)
Biología Computacional , Congresos como Asunto/organización & administración , Biología MolecularAsunto(s)
Carcinoma Basocelular/complicaciones , Carcinoma Basocelular/diagnóstico , Carcinoma de Células Escamosas/complicaciones , Carcinoma de Células Escamosas/diagnóstico , Hipotricosis/complicaciones , Hipotricosis/diagnóstico , Neoplasias Cutáneas/complicaciones , Neoplasias Cutáneas/diagnóstico , Anciano , Humanos , MasculinoRESUMEN
The p53 tumour suppressor is a transcription factor that can either activate or repress the expression of specific genes in response to cellular stresses such as exposure to ultraviolet light. The p53 protein can exert both pro- and anti-apoptotic effects depending on cellular context. In primary human fibroblasts, p53 protects cells from UV-induced apoptosis at moderate doses but this is greatly affected by the nucleotide excision repair (NER) capacity of the cells. The damage-specific DNA binding protein 2 (DDB2) is involved in NER and is associated with xeroderma pigmentosum subgroup E (XP-E). Importantly, DDB2 is also positively regulated by the p53 protein. To study the potential interplay between DDB2 and p53 in determining the apoptotic response of primary fibroblasts exposed to UV light, the expression of these proteins was manipulated in primary normal and XP-E fibroblast strains using human papillomavirus E6 protein (HPV-E6), RNA interference and recombinant adenoviruses expressing either p53 or DDB2. Normal and XP-E fibroblast strains were equally sensitive to UV-induced apoptosis over a broad range of doses and disruption of p53 in these strains using HPV-E6 or RNA interference led to a similar increase in apoptosis following exposure to UV light. In contrast, forced expression of p53 or DDB2 did not affect UV-induced apoptosis greatly in these normal or XP-E fibroblast strains. Collectively, these results indicate that p53 is primarily protective against UV-induced apoptosis in primary human fibroblasts and this activity of p53 does not require DDB2.
Asunto(s)
Apoptosis/efectos de la radiación , Proteínas de Unión al ADN/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Rayos Ultravioleta , Caspasa 3/metabolismo , Caspasa 9/metabolismo , Activación Enzimática/efectos de la radiación , Fibroblastos/enzimología , Fibroblastos/patología , Fibroblastos/efectos de la radiación , Humanos , Masculino , Interferencia de ARN/efectos de la radiación , Proteínas Virales/metabolismo , Xerodermia Pigmentosa/enzimología , Xerodermia Pigmentosa/patologíaRESUMEN
The only curative treatment option for relapsed patients with acute myeloid leukemia (AML) is allogeneic stem cell transplantation. Depletion of hematopoietic stem cells and leukemic blast cells is achieved through the systemic administration of DNA damaging agents, including total-body irradiation (TBI) prior to transplantation. Since other tissues are radiosensitive, the identification of biomarkers could facilitate the management of additional toxicities. Buccal keratinocytes are readily accessible and could provide a source of cells for RNA analysis. In this study, we obtained miRNAs and mRNAs from daily buccal swabs collected from patients undergoing allogeneic stem cell transplantation. Unexpectedly, there was no prominent p53-induced mRNA or miRNA response in these samples, despite the fact that the p53 pathway is a well-characterized radiation-inducible response. Instead, the expression of mRNAs encoding p53 and cytokeratin 14 (TP53 and KRT14, respectively) decreased precipitously within hours of the first radiation treatment. These patients went on to develop oral mucositis, however, it is unclear whether TP53 and/or KRT14 expression are predictive of this adverse event. Larger scale analysis of buccal epithelial samples from patients undergoing allogeneic stem cell transplantation appears to be warranted.
Asunto(s)
Regulación Neoplásica de la Expresión Génica/efectos de la radiación , Trasplante de Células Madre Hematopoyéticas , Queratina-14/genética , Mucosa Bucal/efectos de la radiación , Proteína p53 Supresora de Tumor/genética , Irradiación Corporal Total/efectos adversos , Femenino , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/radioterapia , Leucemia Mieloide Aguda/cirugía , Masculino , Persona de Mediana Edad , Mucosa Bucal/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Factores de Tiempo , Trasplante HomólogoRESUMEN
We have previously shown that the tumor suppressor p53 can play a protective role against UV-induced apoptosis in human fibroblasts. In the present study, we investigated whether the protective function of p53 expression is established before or after UV irradiation. Using a stable human cell line expressing a murine temperature-sensitive p53 in which p53 function could be tightly and reversibly regulated, we found that functional p53 stimulated the induction of apoptosis when expressed for as little as 4-12 h after UV irradiation and that this induction was not dependent on de novo protein synthesis. In contrast, expression of p53 for 12 h or more before UV irradiation reduced the extent of apoptosis even when functional p53 expression was maintained after irradiation. The protection conferred by p53 required ongoing protein synthesis and correlated with enhanced recovery of mRNA synthesis. Together, these results suggest that p53 induces distinct proapoptotic and antiapoptotic signals and that these opposing activities can be separated both temporally and by their requirement for de novo protein synthesis. These findings may have important implications for the refinement of gene therapy approaches combining p53 with pharmacological agents that target transcription or translation.
Asunto(s)
Apoptosis/efectos de la radiación , Proteína p53 Supresora de Tumor/fisiología , Apoptosis/efectos de los fármacos , Ciclo Celular , Cicloheximida/farmacología , Citometría de Flujo , Células HT29 , Humanos , Modelos Biológicos , Biosíntesis de Proteínas/efectos de los fármacos , Inhibidores de la Síntesis de la Proteína/farmacología , Temperatura , Factores de Tiempo , Transcripción Genética/efectos de la radiación , Proteína p53 Supresora de Tumor/metabolismo , Rayos UltravioletaRESUMEN
T-type calcium channel isoforms are expressed in a multitude of tissues and have a key role in a variety of physiological processes. To fully appreciate the physiological role of distinct channel isoforms it is essential to determine their kinetic properties under physiologically relevant conditions. We therefore characterized the gating behavior of expressed rat voltage-dependent calcium channels (Ca(v)) 3.1, Ca(v)3.2, and Ca(v)3.3, as well as human Ca(v)3.3 at 21 degrees C and 37 degrees C in saline that approximates physiological conditions. Exposure to 37 degrees C caused significant increases in the rates of activation, inactivation, and recovery from inactivation, increased the current amplitudes, and induced a hyperpolarizing shift of half-activation for Ca(v)3.1 and Ca(v)3.2. At 37 degrees C the half-inactivation showed a hyperpolarizing shift for Ca(v)3.1 and Ca(v)3.2 and human Ca(v)3.3, but not rat Ca(v)3.3. The observed changes in the kinetics were significant but not identical for the three isoforms, showing that the ability of T-type channels to conduct calcium varies with both channel isoform and temperature.
Asunto(s)
Temperatura Corporal/fisiología , Canales de Calcio Tipo T/genética , Señalización del Calcio/genética , Membrana Celular/genética , Activación del Canal Iónico/genética , Animales , Línea Celular , Humanos , Cinética , Potenciales de la Membrana/genética , Proteínas de Transporte de Membrana/genética , Sistema Nervioso/metabolismo , Neuronas/metabolismo , Técnicas de Placa-Clamp , Isoformas de Proteínas/genética , RatasRESUMEN
Allele loss involving chromosome arm 3p is one of the most frequent and earliest known genetic events in lung cancer pathogenesis and may affect several potential tumor suppressor gene regions. To further study the role of chromosome 3p allele loss in the pathogenesis of lung cancer, we performed high resolution loss of heterozygosity (LOH) studies on 97 lung cancer and 54 preneoplastic/preinvasive microdissected respiratory epithelial samples using a panel of 28 3p markers. Allelic losses of 3p were detected in 96% of the lung cancers and in 78% of the preneoplastic/preinvasive lesions. The allele losses were often multiple and discontinuous, with areas of LOH interspersed with areas of retention of heterozygosity. Most small cell lung carcinomas (91%) and squamous cell carcinomas (95%) demonstrated larger 3p segments of allele loss, whereas most (71%) of the adenocarcinomas and preneoplastic/preinvasive lesions had smaller chromosome areas of 3p allele loss. There was a progressive increase in the frequency and size of 3p allele loss regions with increasing severity of histopathological preneoplastic/preinvasive changes. In analyses of the specific parental allele lost comparing 42 preneoplastic/preinvasive foci with those lost in the lung cancer in the same patient (n = 10), the same parental allele was lost in 88% of 244 comparisons for 28 3p markers (P = 1.2 x 10(-36) for this occurring by chance). This indicates the occurrence of allele-specific loss in these foci similar to that seen in the tumor by a currently unknown mechanism. Analysis of all of the data indicated multiple regions of localized 3p allele loss including telomere-D3S1597, D3S1111-D3S2432, D3S2432-D3S1537, D3S1537, D3S1537-D3S1612, D3S4604/Luca19.1-D3S4622/Luca4.1, D3S4624/Luca2.1, D3S4624/Luca2.1-D3S1582, D3S1766, D3S1234-D3S1300 (FHIT/FRA3B region centered on D3S1300), D3S1284-D3S1577 (U2020/DUTT1 region centered on D3S1274), and D3S1511-centromere. A panel of six markers in the 600-kb 3p21.3 deletion region showed loss in 77% of the lung cancers, 70% of normal or preneoplastic/preinvasive lesions associated with lung cancer, and 49% of 47 normal, mildly abnormal, or preneoplastic/preinvasive lesions found in smokers without lung cancer; however, loss was seen in 0% of 18 epithelial samples from seven never smokers. The 600-kb 3p21.3 region and the 3p14.2 (FHIT/FRA3B) and 3p12 (U2020/DUTT1) regions were common, independent sites of breakpoints (retention of heterozygosity by some markers and LOH by other markers in the immediate region). We conclude that 3p allele loss is nearly universal in lung cancer pathogenesis; involves multiple, discrete, 3p LOH sites that often show a "discontinuous LOH" pattern in individual tumors; occurs in preneoplastic/preinvasive lesions in smokers with and without lung cancer (multiple lesions often lose the same parental allele); frequently involves breakpoints in at least three very small defined genomic regions; and appears to have allele loss and breakpoints first occurring in the 600-kb 3p21.3 region. These findings are consistent with previously reported LOH studies in a variety of tumors showing allele loss occurring by mitotic recombination and induced by oxidative damage.
Asunto(s)
Bronquios/patología , Rotura Cromosómica , Cromosomas Humanos Par 3 , Neoplasias Pulmonares/genética , Lesiones Precancerosas/genética , Mucosa Respiratoria/patología , Adulto , Anciano , Anciano de 80 o más Años , Alelos , Carcinoma de Pulmón de Células no Pequeñas/genética , Carcinoma de Pulmón de Células no Pequeñas/patología , Carcinoma de Células Pequeñas/genética , Carcinoma de Células Pequeñas/patología , Deleción Cromosómica , Mapeo Cromosómico , Femenino , Marcadores Genéticos , Humanos , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana Edad , Invasividad Neoplásica , Lesiones Precancerosas/patología , Células Tumorales CultivadasRESUMEN
We previously reported that transcription-coupled repair (TCR)-deficient human fibroblasts are extremely sensitive to UV-induced apoptosis and this sensitivity correlated with the induction of the p53 tumour suppressor. However, we have also found that p53 can be protective against UV-induced apoptosis. Thus, prior to this study, it was not clear whether the induction of p53 in TCR-deficient fibroblasts contributed to their death. To address this issue, we have expressed human papillomavirus E6 (HPV-E6) in primary fibroblasts derived from patients affected with xeroderma pigmentosum (complementation groups A, B and C) and Cockayne syndrome (complementation group B). We found that TCR-deficient (XP-A, XP-B and CS-B) fibroblasts were more sensitive than TCR-proficient cells (XP-C and normal) to both UV light and cisplatin treatment and this increase in sensitivity was not p53 dependent. Importantly, HPV-E6 expression increased the sensitivity of TCR-proficient normal and XP-C fibroblasts to UV- and cisplatin-induced apoptosis. This increase in sensitivity correlated with a decrease in the capacity of HPV-E6 expressing cells to recover mRNA synthesis following UV-irradiation. Therefore, we propose that p53 protects against UV- and cisplatin-induced apoptosis in a TCR-dependent manner and that p53 does not contribute strongly to the induction of apoptosis in TCR-deficient fibroblasts.
Asunto(s)
Apoptosis , Cisplatino/farmacología , Reparación del ADN , Fibroblastos/metabolismo , Proteínas Represoras , Transcripción Genética , Proteína p53 Supresora de Tumor/metabolismo , Rayos Ultravioleta , Síndrome de Cockayne/metabolismo , Síndrome de Cockayne/patología , Relación Dosis-Respuesta a Droga , Relación Dosis-Respuesta en la Radiación , Humanos , Proteínas Oncogénicas Virales/metabolismo , ARN Mensajero/metabolismo , Fármacos Sensibilizantes a Radiaciones/farmacología , Xerodermia Pigmentosa/metabolismo , Xerodermia Pigmentosa/patologíaRESUMEN
Ultraviolet light (UV) induced DNA lesions efficiently block transcript elongation and induce the p53 response. Although p53 contributes to transcriptional activation of the p21waf1 and bax genes, accumulation of these proteins requires that these genes are free of UV induced pyrimidine dimers. We assessed the level of expression of p53 and the p53 regulated p21waf1 and bax gene products in normal diploid fibroblasts (NDF) and several nucleotide excision repair deficient fibroblasts following UV-irradiation. At low UV fluences, increased expression of p53, p21waf1 and bax was only observed in fibroblasts deficient in transcription coupled repair (TCR). Whereas p53 protein levels increased in all cell types at high UV fluences, p21waf1 levels initially decreased and then recovered in a manner dependent on TCR. At later times, expression of p21waf1 and bax was only elevated in TCR-proficient cells. The lack of TCR strongly correlated with an enhanced induction of apoptosis. Furthermore, we assessed the effect of modulation of the p53/p21waf1/pRb pathway on clonogenic survival following UV irradiation. Expression of E2F-1, E2F-4, and the large tumour antigens of SV40 and Polyomavirus conferred UV sensitivity to NDF whereas p21waf1 protected cells against UV treatment. We propose that the fluence dependent attenuation of protective functions of p53 by blockage of transcription favours apoptosis following UV exposure.
Asunto(s)
Apoptosis , Ciclinas/biosíntesis , Daño del ADN/efectos de la radiación , Reparación del ADN , Proteínas Proto-Oncogénicas c-bcl-2/biosíntesis , Proteínas Proto-Oncogénicas/biosíntesis , Rayos Ultravioleta , Línea Celular , Línea Celular Transformada , Inhibidor p21 de las Quinasas Dependientes de la Ciclina , Diploidia , Fibroblastos/citología , Fibroblastos/metabolismo , Regulación de la Expresión Génica , Humanos , Proteína de Retinoblastoma/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Proteína X Asociada a bcl-2RESUMEN
The mechanisms by which the p53 response is triggered following exposure to DNA-damaging agents have not yet been clearly elucidated. We and others have previously suggested that blockage of RNA polymerase II may be the trigger for induction of the p53 response following exposure to ultraviolet light. Here we report on the correlation between inhibition of mRNA synthesis and the induction of p53, p21WAF1 and apoptosis in diploid human fibroblasts treated with either UV light, cisplatin or the RNA synthesis inhibitors actinomycin D, DRB, H7 and alpha-amanitin. Exposure to ionizing radiation or the proteasome inhibitor LLnL, however, induced p53 and p21WAF1 without affecting mRNA synthesis. Importantly, induction of p53 by the RNA synthesis or proteasome inhibitors did not correlate with the induction of DNA strand breaks. Furthermore, cisplatin-induced accumulation of active p53 in repair-deficient XP-A cells occurred despite the lack of DNA strand break induction. Our results suggest that the induction of the p53 response by certain toxic agents is not triggered by DNA strand breaks but rather, may be linked to inhibition of mRNA synthesis either directly by the poisoning of RNA polymerase II or indirectly by the induction of elongation-blocking DNA lesions.
Asunto(s)
ARN Polimerasa II/antagonistas & inhibidores , Proteína p53 Supresora de Tumor/metabolismo , Apoptosis , Cisplatino/farmacología , Cisteína Endopeptidasas , Daño del ADN , Humanos , Complejos Multienzimáticos , Inhibidores de la Síntesis del Ácido Nucleico/farmacología , Complejo de la Endopetidasa Proteasomal , ARN/biosíntesis , ARN Mensajero/biosíntesis , Fármacos Sensibilizantes a Radiaciones/farmacología , Rayos UltravioletaRESUMEN
We have previously suggested that the inhibition of RNA polymerase II-mediated transcription after exposure to UV light promotes the accumulation of p53 and the induction of apoptosis (Oncogene 13, 823-831). However, it was not clear whether p53 induction was contributing to apoptosis. Here we report that apoptosis is triggered at lower UV doses in p53-deficient Li-Fraumeni syndrome (LFS) and human papillomavirus (HPV) E6 expressing fibroblasts than in normal cells, suggesting that p53 can be protective against UV-induced apoptosis. There is no significant difference in the effect of UV-irradiation on the cell cycle distribution of normal and primary LFS fibroblasts. Importantly, the recovery of nascent mRNA synthesis in all p53-deficient fibroblasts is significantly impaired compared with control cells after exposure to relevant doses of UV light. Taken together, our results suggest that wild-type p53 can protect cells against UV-induced apoptosis by facilitating the recovery of transcription. Furthermore, we suggest that the capacity of cells to recover transcription after genotoxic damage is an important determinant of sensitivity to apoptosis.
Asunto(s)
Apoptosis/efectos de la radiación , Transcripción Genética , Proteína p53 Supresora de Tumor/fisiología , Células Cultivadas , Reparación del ADN , Fibroblastos/efectos de la radiación , Fase G1 , Humanos , ARN Mensajero/biosíntesis , Neoplasias Cutáneas/etiología , Rayos UltravioletaRESUMEN
The density of Na/K adenosine triphosphatase (ATPase) pumps in retinal pigment epithelial (RPE) cells in different retinal regions was quantified by measuring the binding of 3H-ouabain to RPE in cow and human eyecups. In bovine eyes, pump density was estimated in RPE samples isolated from three retinal regions outlined with a 7-mm trephine: one from the posterior pole in the area centralis and two from the superior, equatorial retina representing unpigmented (in the tapetum) and pigmented zones. In human eyes, RPE samples were isolated from a posterior region centered around the macula and one superior region. Ouabain binding to RPE of the posterior pole of both species was approximately 40-60% lower than binding to RPE of more peripheral regions in the same eyes. For bovine eyes, ouabain binding did not differ between pigmented and unpigmented cells of the superior retina, suggesting that reduced binding in the relatively amelanotic posterior cells was not related to levels of pigmentation. For human RPE, binding to posterior cells was lower in eyes from donors of all ages (range, 17-90 yr). The data suggest that Na/K ATPase pump site density is lower in posterior RPE cells of both bovine and human eyes, perhaps due to a regional difference in requirements for ionic regulation.
Asunto(s)
Epitelio Pigmentado Ocular/enzimología , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Animales , Bovinos , Fóvea Central/enzimología , Humanos , Mácula Lútea/enzimología , Persona de Mediana Edad , Ouabaína/metabolismo , Epitelio Pigmentado Ocular/anatomía & histología , Distribución AleatoriaRESUMEN
PURPOSE: To characterize the response of cultured human retinal pigment epithelial (RPE) cells to lowered environmental oxygen. METHODS: The response of cultured RPE cells to lowered oxygen environments was compared to that of cell types of presumed high (Madin-Darby canine kidney [MDCK] cells, an epithelial cell line) and low (CSF, corneal stromal fibroblasts) aerobic requirements. Cultures in a range of densities were exposed for 7 days to 3%, 8%, or 20% O2 with measurements of adenosine triphosphate (ATP), cell number, and cytochrome oxidase (CO) activity (an enzyme marker of aerobic metabolism). RESULTS: RPE cells had levels of CO activity and total cellular ATP intermediate between those of CSF (low) and MDCK (high) in all oxygen environments. Hypoxia led to modestly lowered ATP pools and CO activity for RPE cells over a wide range of culture densities. Hypoxia induced a greater cell loss in MDCK cells than in RPE cells, and the effects of hypoxia were greater in dense cultures of both epithelial cell types. Hypoxia had little effect on cell number for CSF. CONCLUSIONS: The data suggest that cultured RPE cells, though aerobically active, are not as dependent upon oxidative phosphorylation and are more resistant to hypoxia than MDCK cells, a cell type derived from another well-perfused tissue. The authors conclude that RPE cells are unlikely to suffer from hypoxic injury in situ because of a moderate aerobic demand and an abundant oxygen supply.
Asunto(s)
Hipoxia de la Célula/fisiología , Epitelio Pigmentado Ocular/metabolismo , Adenosina Trifosfato/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Recuento de Células , Línea Celular , Células Cultivadas , Preescolar , Sustancia Propia/citología , Sustancia Propia/metabolismo , Complejo IV de Transporte de Electrones/metabolismo , Epitelio/metabolismo , Fibroblastos/metabolismo , Humanos , Riñón/citología , Riñón/metabolismo , Persona de Mediana Edad , Oxígeno/metabolismo , Epitelio Pigmentado Ocular/citologíaRESUMEN
The clearance of tissue plasminogen activator (t-PA) injected into the midvitreous cavity was studied in the phakic, vitrectomized rabbit eye with and without intravitreal fibrin clots. The quantity and activity of t-PA in the vitreous, serum, and aqueous were determined at ten minutes and at 3, 6, 15, 24, and 48 hours after initial injection by an enzyme-linked immunosorbent assay (ELISA) and a spectrophotometric solid-phase fibrin assay (SOFIA). In eyes without an intravitreal fibrin clot, the estimated half-life for t-PA was 4.3 hours by SOFIA and 5.8 hours by ELISA. In eyes containing a vitreal fibrin clot, the half-life increased to 9.8 hours by SOFIA and 11.9 hours by ELISA. Both of these half-lives were significantly greater than the half-life for eyes without fibrin. Regardless of the presence of fibrin, intravitreal t-PA activity was significantly less than t-PA quantity, suggesting the presence of a t-PA inhibitor. A peak in aqueous t-PA occurred before six hours, indicating that t-PA was cleared in part through the anterior chamber. There was no measurable serum t-PA at any of the sampling times.