RESUMEN

Altered expression of the eukaryotic translation initiation factor 3 (eIF3) subunit eIF3e/INT6 has been described in various types of human cancer, but the nature of its involvement in tumorigenesis is not yet clear. Using immunohistochemical analysis of 81 primary breast cancers, we found that high tumor grade correlated significantly with elevated cytoplasmic eIF3e level in epithelial tumor cells. Analysis of protein synthesis after siRNA-mediated knockdown in breast cancer cell lines indicated that eIF3e is not required for bulk translation. Microarray analysis of total and polysomal RNAs nonetheless identified distinct sets of mRNAs regulated either positively or negatively by eIF3e; functional classification of these revealed a marked enrichment of genes involved in cell proliferation, invasion and apoptosis. Validated mRNA targets regulated positively at the translational level by eIF3e included urokinase-type plasminogen activator and apoptotic regulator BCL-XL, whereas synthesis of proteins including the mitotic checkpoint component MAD2L1 was negatively regulated. Finally, eIF3e-depleted breast carcinoma cells showed reduced in vitro invasion and proliferation. Taken together, our study data suggest that eIF3e has a positive role in breast cancer progression. It regulates the translation, and in some cases abundance, of mRNAs involved in key aspects of cancer cell biology.

Asunto(s)

Neoplasias de la Mama/genética , Factor 3 de Iniciación Eucariótica/fisiología , Proteínas de Choque Térmico/fisiología , Oncogenes , Femenino , Humanos

RESUMEN

To gain insight into the molecular pathogenesis of the myelodysplastic syndromes (MDS), we performed global gene expression profiling and pathway analysis on the hematopoietic stem cells (HSC) of 183 MDS patients as compared with the HSC of 17 healthy controls. The most significantly deregulated pathways in MDS include interferon signaling, thrombopoietin signaling and the Wnt pathways. Among the most significantly deregulated gene pathways in early MDS are immunodeficiency, apoptosis and chemokine signaling, whereas advanced MDS is characterized by deregulation of DNA damage response and checkpoint pathways. We have identified distinct gene expression profiles and deregulated gene pathways in patients with del(5q), trisomy 8 or -7/del(7q). Patients with trisomy 8 are characterized by deregulation of pathways involved in the immune response, patients with -7/del(7q) by pathways involved in cell survival, whereas patients with del(5q) show deregulation of integrin signaling and cell cycle regulation pathways. This is the first study to determine deregulated gene pathways and ontology groups in the HSC of a large group of MDS patients. The deregulated pathways identified are likely to be critical to the MDS HSC phenotype and give new insights into the molecular pathogenesis of this disorder, thereby providing new targets for therapeutic intervention.

Asunto(s)

Biomarcadores de Tumor/genética , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Células Madre Hematopoyéticas/metabolismo , Síndromes Mielodisplásicos/genética , Transducción de Señal , Biomarcadores de Tumor/metabolismo , Estudios de Casos y Controles , Deleción Cromosómica , Cromosomas Humanos Par 5/genética , Cromosomas Humanos Par 7/genética , Cromosomas Humanos Par 8/genética , Células Madre Hematopoyéticas/patología , Humanos , Síndromes Mielodisplásicos/metabolismo , Análisis de Secuencia por Matrices de Oligonucleótidos , ARN Mensajero/genética , ARN Mensajero/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Trisomía

RESUMEN

Cisplatin is a chemotherapeutic agent that induces tumor necrosis factor-alpha (TNF-alpha) production in many cell types with unfortunate renal toxicity. We sought to determine the contributions of renal parenchymal cells and bone marrow-derived immune cells to the pathogenesis of cisplatin-induced renal injury in vivo. To do this we created chimeric mice in which the bone marrow was ablated and replaced with donor bone marrow cells from wild-type or from TNF-alpha knockout mice. Six weeks after reconstitution, the chimeric mice were treated with cisplatin and renal structural and functional parameters were measured. Chimeras with kidneys of wild-type animals all developed significant renal failure after 72 h of cisplatin treatment regardless of the immune cell source. Chimeras with kidneys of TNF-alpha knockout mice showed significantly less renal dysfunction (blood urea nitrogen, serum creatinine, and glomerular filtration rate), renal histologic injury, and serum TNF-alpha levels; again regardless of the immune cell source. Urinary excretion of several proinflammatory cytokines was lower in the wild-type bone marrow-knockout kidney chimera mouse than in wild-type background mice. Our results indicate that a substantial portion of circulating and urinary TNF-alpha is derived from nonimmune cells after cisplatin administration. We conclude that the production of TNF-alpha by renal parenchymal cells, rather than by bone marrow-derived infiltrating immune cells, is responsible for cisplatin-induced nephrotoxicity.

Asunto(s)

Lesión Renal Aguda/inducido químicamente , Lesión Renal Aguda/patología , Antineoplásicos/efectos adversos , Cisplatino/efectos adversos , Nefronas/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Lesión Renal Aguda/metabolismo , Animales , Antineoplásicos/farmacología , Nitrógeno de la Urea Sanguínea , Células de la Médula Ósea/inmunología , Células de la Médula Ósea/metabolismo , Quimera/genética , Cisplatino/farmacología , Creatinina/sangre , Citocinas/orina , Modelos Animales de Enfermedad , Regulación de la Expresión Génica/efectos de los fármacos , Tasa de Filtración Glomerular/efectos de los fármacos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Nefronas/efectos de los fármacos , Nefronas/patología , Receptores del Factor de Necrosis Tumoral/genética , Receptores del Factor de Necrosis Tumoral/metabolismo , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Factor de Necrosis Tumoral alfa/genética

RESUMEN

Over the last 15 years genetic testing by DNA analysis has expanded enormously both in volume and range due to advances in scientific knowledge and analytical technology. This type of analysis has the potential to provide rapid, cost effective, and accurate diagnostic information but also has its limitations. Some of the changes detected may be of ambiguous consequence and as the knowledge base expands so too does the recognition that other factors can influence the clinical picture. In many cases outcomes may be predicted only on a statistical basis rather than individually. Careful attention should therefore be given to the clinical question that is being addressed before such testing is requested.

Asunto(s)

ADN/análisis , Técnicas de Diagnóstico Molecular/métodos , Análisis Mutacional de ADN/métodos , Pruebas Genéticas/métodos , Humanos , Consentimiento Informado

RESUMEN

Children with language impairments have limitations of phonological short-term memory (STM) and have distinctive problems with certain aspects of grammar. Both deficits have been proposed as phenotypic markers of heritable language impairment. We studied 173 twin pairs, selected to be over-representative of children with risk of developmental language impairment, using a battery of standardized language and intelligence tests, a test of nonword repetition to index phonological STM and two elicitation tasks to assess use of verb tense marking. As predicted, the phonological STM and the verb tense measures both discriminated children with risk of language impairment from low risk children, and DeFries-Fulker analysis showed that impairments on both tasks were significantly heritable. However, there was minimal phenotypic and etiological overlap between the two deficits, suggesting that different genes are implicated in causing these two kinds of language difficulty. From an evolutionary perspective, these data are consistent with the view that language is a complex function that depends on multiple underlying skills with distinct genetic origins.

Asunto(s)

Predisposición Genética a la Enfermedad/genética , Trastornos del Desarrollo del Lenguaje/genética , Desarrollo del Lenguaje , Trastornos de la Memoria/complicaciones , Trastornos de la Memoria/genética , Memoria a Corto Plazo/fisiología , Envejecimiento/fisiología , Evolución Biológica , Niño , Femenino , Humanos , Patrón de Herencia/genética , Trastornos del Desarrollo del Lenguaje/diagnóstico , Trastornos del Desarrollo del Lenguaje/psicología , Pruebas del Lenguaje , Masculino , Trastornos de la Memoria/psicología , Modelos Neurológicos , Pruebas Neuropsicológicas , Fenotipo , Factores de Riesgo , Conducta Verbal/fisiología

RESUMEN

The Int-6 gene is a site of mouse mammary tumour virus (MMTV) integration in murine tumours and INT6 protein has been identified independently as a subunit (eIF3e) of the eukaryotic translation initiation factor eIF3. In addition, the protein can interact with two other multi-subunit complexes: the COP9 signalosome (CSN) and the proteasome. The role of INT6 in tumourigenesis is nonetheless currently unclear. Here, using immunofluorescence microscopy, we show that eIF3e/INT6 is localized in part to the nucleus, while other eIF3 components are cytoplasmic. Primary human fibroblasts, but not their transformed counterparts, showed reduced nuclear INT6 staining in some cells, and this reduction was maximal in early S phase. This variation in eIF3e/INT6 may indicate regulated shuttling between cellular compartments and would be consistent with the presence of a nuclear export signal as well as a nuclear localization signal in the protein sequence. Loss of regulation of eIF3e/INT6 redistribution may therefore be a significant feature of malignancy in human cells.

Asunto(s)

Compartimento Celular/genética , Ciclo Celular/genética , Núcleo Celular/metabolismo , Factor 3 de Iniciación Eucariótica/metabolismo , Fibroblastos/metabolismo , Fibrosarcoma/metabolismo , Transporte Activo de Núcleo Celular/genética , Núcleo Celular/genética , Células Cultivadas , Factor 3 de Iniciación Eucariótica/genética , Fibroblastos/ultraestructura , Fibrosarcoma/ultraestructura , Técnica del Anticuerpo Fluorescente , Humanos , Subunidades de Proteína/genética , Subunidades de Proteína/metabolismo , Transducción de Señal/genética

RESUMEN

Regulation of protein synthesis at the level of translation initiation is fundamentally important for the control of cell proliferation under normal physiological conditions. Conversely, misregulation of protein synthesis is emerging as a major contributory factor in cancer development. Most bulk protein synthesis is initiated via recognition of the mRNA 5' cap and subsequent recognition of the initiator AUG codon by a directional scanning mechanism. However, several key regulators of tumour development are translated by a cap-independent pathway. Here we review eukaryotic translation initiation, its regulation and the ways in which this regulation can break down during tumorigenesis.

Asunto(s)

Transformación Celular Neoplásica , Regulación Neoplásica de la Expresión Génica , Factores de Iniciación de Péptidos/farmacología , Biosíntesis de Proteínas , Animales , Células Eucariotas/fisiología , Humanos , Neoplasias/fisiopatología , ARN Mensajero

RESUMEN

The heterodimeric cyclin B/Cdc2 protein kinase governs entry into mitosis, and can be negatively regulated through p53-mediated transcriptional induction of the cyclin-dependent kinase inhibitor p21(WAF1/CIP1). Ectopic expression of p21(WAF1/CIP1) in cultured cells has been shown previously to influence the subcellular distribution of the cyclin-dependent kinases (CDKs) including Cdc2. In this study, we have examined the subcellular localisation of Cdc2, cyclin B and p21(WAF1/CIP1) by immunohistochemistry in a well characterised series of primary breast cancers. Surprisingly, p21(WAF1/CIP1) was predominantly cytoplasmic in many of the tumours, where it was associated with high p53 levels; cytoplasmic p21(WAF1/CIP1) and high cyclin B levels were also significant predictors of poor prognosis. We conclude that breast tumorigenesis may be characterised by abnormalities in pathways determining not only levels of expression of key regulatory molecules, but also their subcellular localisation. Investigation of the subcellular distribution of cell cycle regulatory proteins, particularly p21(WAF1/CIP1), could provide valuable prognostic markers in breast cancer.

Asunto(s)

Neoplasias de la Mama/química , Proteína Quinasa CDC2/análisis , Carcinoma Ductal de Mama/química , Ciclina B/análisis , Ciclinas/análisis , Proteínas de Neoplasias/análisis , Adulto , Anciano , Anciano de 80 o más Años , Inhibidor p21 de las Quinasas Dependientes de la Ciclina , Supervivencia sin Enfermedad , Humanos , Inmunohistoquímica , Metástasis Linfática , Persona de Mediana Edad , Análisis Multivariante , Recurrencia Local de Neoplasia/química , Valor Predictivo de las Pruebas , Proteína p53 Supresora de Tumor/análisis

RESUMEN

In the budding yeast Saccharomyces cerevisiae the Srs2/RadH DNA helicase promotes survival after ultraviolet (UV) irradiation, and has been implicated in DNA repair, recombination and checkpoint signalling following DNA damage. A second helicase, Sgs1, is the S.cerevisiae homologue of the human BLM and WRN proteins, which are defective in cancer predisposition and/or premature ageing syndromes. Saccharomyces cerevisiae cells lacking both Srs2 and Sgs1 exhibit a severe growth defect. We have identified an Srs2 orthologue in the fission yeast Schizosaccharomyces pombe, and have investigated its role in responses to UV irradiation and inhibition of DNA replication. Deletion of fission yeast srs2 caused spontaneous hyper-recombination and UV sensitivity, and simultaneous deletion of the SGS1 homologue rqh1 caused a severe growth defect reminiscent of that seen in the equivalent S.cerevisiae mutant. However, unlike in budding yeast, inactivation of the homologous recombination pathway did not suppress this growth defect. Indeed, the homologous recombination pathway was required for maintenance of normal fission yeast viability in the absence of Srs2, and loss of homologous recombination and loss of Srs2 contributed additively to UV sensitivity. We conclude that Srs2 plays related, but not identical, roles in the two yeast species.

Asunto(s)

Daño del ADN , ADN Helicasas/metabolismo , Proteínas de Unión al ADN , Proteínas de Saccharomyces cerevisiae , Proteínas de Schizosaccharomyces pombe , Schizosaccharomyces/genética , Secuencia de Aminoácidos , División Celular/efectos de los fármacos , División Celular/genética , División Celular/efectos de la radiación , ADN Helicasas/genética , Reparación del ADN , ADN-Topoisomerasas de Tipo I/genética , Proteínas Fúngicas/genética , Eliminación de Gen , Regulación Enzimológica de la Expresión Génica , Regulación Fúngica de la Expresión Génica , Genes Letales , Hidroxiurea/farmacología , Datos de Secuencia Molecular , Fenotipo , Recombinasa Rad51 , Recombinación Genética , Schizosaccharomyces/enzimología , Homología de Secuencia de Aminoácido , Rayos Ultravioleta

RESUMEN

CD8(+) CTLs play a pivotal role in immune responses against many viruses and tumors. Two models have been proposed. The "three-cell" model focuses on the role of CD4(+) T cells, proposing that help is only provided to CTLs by CD4(+) T cells that recognize Ag on the same APC. The sequential "two-cell" model proposes that CD4(+) T cells can first interact with APCs, which in turn activate naive CTLs. Although these models provide a general framework for the role of CD4(+) T cells in mediating help for CTLs, a number of issues are unresolved. We have investigated the induction of CTL responses using dendritic cells (DCs) to immunize mice against defined peptide Ags. We find that help is required for activation of naive CTLs when DCs are used as APCs, regardless of the origin or MHC class I restriction of the peptides we studied in this system. However, CD8(+) T cells can provide self-help if they are present at a sufficiently high precursor frequency. The important variable is the total number of T cells responding, because class II-knockout DCs pulsed with two noncompeting peptides are effective in priming.

Asunto(s)

Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Activación de Linfocitos , Transducción de Señal/inmunología , Animales , Células Presentadoras de Antígenos/inmunología , Antígenos Virales/inmunología , Linfocitos T CD8-positivos/citología , Linfocitos T CD8-positivos/virología , Comunicación Celular/genética , Comunicación Celular/inmunología , Células Cultivadas , Citotoxicidad Inmunológica/genética , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Epítopos de Linfocito T/inmunología , Glicoproteínas/inmunología , Antígenos de Histocompatibilidad Clase II/biosíntesis , Interfase/genética , Interfase/inmunología , Activación de Linfocitos/genética , Virus de la Coriomeningitis Linfocítica/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Fragmentos de Péptidos/inmunología , Transducción de Señal/genética , Bazo/citología , Bazo/inmunología , Proteínas Virales/inmunología

RESUMEN

Vertebrates express three cytokine-inducible proteasome subunits that are incorporated in the place of their constitutively synthesized counterparts. There is increasing evidence that the set of peptides generated by proteasomes containing these subunits (immunoproteasomes) differs from that produced by standard proteasomes. In this study, we use mice lacking one of the immunoproteasome subunits (LMP2) to show that immunoproteasomes play an important role in establishing the immunodominance hierarchy of CD8(+) T cells (T(CD8+)) responding to seven defined determinants in influenza virus. In LMP2(-/)- mice, responses to the two most dominant determinants drop precipitously, whereas responses to two subdominant determinants are greatly enhanced. Adoptive transfer experiments with naive normal and transgenic T(CD8+) reveal that the reduced immunogenicity of one determinant (PA(224-233)) can be attributed to decreased generation by antigen presenting cells (APCs), whereas the other determinant (NP(366-374)) is less immunogenic due to alterations in the T(CD8+) repertoire, and not, as reported previously, to the decreased capacity of LMP2(-/)- APCs to generate the determinant. The enhanced response to one of the subdominant determinants (PB1F2(62-70)) correlates with increased generation by LMP2(-)(/)- virus-infected cells. These findings indicate that in addition to their effects on the presentation of foreign antigens, immunoproteasomes influence T(CD8+) responses by modifying the repertoire of responding T(CD8+).

Asunto(s)

Presentación de Antígeno , Antígenos Virales/metabolismo , Linfocitos T CD8-positivos/inmunología , Cisteína Endopeptidasas/fisiología , Complejos Multienzimáticos/fisiología , Infecciones por Orthomyxoviridae/inmunología , Orthomyxoviridae/inmunología , Proteínas/fisiología , Animales , Ratones , Ratones Endogámicos C57BL , Complejo de la Endopetidasa Proteasomal , Células Tumorales Cultivadas

RESUMEN

Regions of hypoxia are a common feature of solid tumours. When tumour cells are exposed to hypoxic stress, transcription of a battery of genes is initiated. The angiogenic factor adrenomedullin (ADM) is a hypoxia regulated gene. ADM is thought to act through the G protein-coupled receptor calcitonin receptor-like receptor (CRLR), with specificity being conferred by the receptor associated modifying protein 2 (RAMP2). Here we report for the first time that ADM treated or stably transfected Ishikawa cells overexpressing ADM show increased resistance to hypoxia induced apoptosis. These cells also show an upregulation of the oncoprotein Bcl-2, which is protective against hypoxic cell death when transiently transfected into Ishikawa cells. Since Ishikawa cells express the putative ADM-receptor CRLR-RAMP2 the production and secretion of ADM with the consecutive upregulation of Bcl-2 could establish an autocrine/paracrine mechanism rescuing malignant cells from hypoxic cell death. These results, taken together with our previous findings that ADM is an angiogenic factor which is upregulated by the nonsteroidal antiestrogen tamoxifen (TAM) in endometrial cells, implicate this peptide as a promoter of tumour growth and a possible target for anticancer strategies.

Asunto(s)

Neoplasias Endometriales/metabolismo , Neoplasias Endometriales/patología , Péptidos/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/genética , Adrenomedulina , Proteína Similar al Receptor de Calcitonina , División Celular/efectos de los fármacos , División Celular/fisiología , Hipoxia de la Célula/efectos de los fármacos , Hipoxia de la Célula/fisiología , Supervivencia Celular/efectos de los fármacos , Neoplasias Endometriales/genética , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Péptidos y Proteínas de Señalización Intracelular , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Péptidos/genética , Péptidos/farmacología , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Proteína 2 Modificadora de la Actividad de Receptores , Proteínas Modificadoras de la Actividad de Receptores , Receptores de Calcitonina/genética , Receptores de Calcitonina/metabolismo , Transfección , Células Tumorales Cultivadas , Regulación hacia Arriba

Asunto(s)

Factores de Iniciación de Péptidos/química , Terminología como Asunto , Animales , Caenorhabditis elegans/química , Drosophila melanogaster/química , Factor 3 de Iniciación Eucariótica , Humanos , Proteínas de Plantas/química , Saccharomyces cerevisiae/química

RESUMEN

CD8 T cells (T(CD8+)) play a crucial role in immunity to viruses. Current understanding of activation of naive T cells entails Ag presentation by professional APCs (pAPCs). What happens, however, when viruses evolve to avoid infecting pAPCs? We have studied the consequences of this strategy by generating recombinant adenoviruses that express influenza A virus nucleoprotein under the control of tissue-specific promoters. We show that the immunogenicity of such viruses requires their delivery to organs capable of expressing nucleoprotein. This indicates that infection of pAPCs is not required for adenoviruses to elicit a T(CD8+) response, probably due to a cross-priming via pAPCs. While this bodes well for recombinant adenoviruses as vaccines, it dims their prospects as gene therapy vectors.

Asunto(s)

Adenoviridae/genética , Adenoviridae/inmunología , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/virología , Nucleoproteínas/genética , Nucleoproteínas/inmunología , Proteínas de Unión al ARN , Proteínas del Núcleo Viral/genética , Proteínas del Núcleo Viral/inmunología , Animales , Citomegalovirus/genética , Citomegalovirus/inmunología , Citotoxicidad Inmunológica/genética , Células Epiteliales/inmunología , Células Epiteliales/virología , Femenino , Vectores Genéticos/administración & dosificación , Vectores Genéticos/inmunología , Antígenos de Histocompatibilidad Clase II/genética , Virus de la Influenza A/genética , Virus de la Influenza A/inmunología , Queratinocitos/inmunología , Queratinocitos/virología , Activación de Linfocitos/genética , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones SCID , Proteínas de la Nucleocápside , Nucleoproteínas/biosíntesis , Especificidad de Órganos/genética , Especificidad de Órganos/inmunología , Regiones Promotoras Genéticas/inmunología , Alveolos Pulmonares/citología , Alveolos Pulmonares/inmunología , Alveolos Pulmonares/virología , Timo/citología , Timo/inmunología , Timo/virología , Proteínas del Núcleo Viral/biosíntesis

RESUMEN

We have previously shown that genes involved in a novel pathway of multidrug resistance (MDR) in the fission yeast Schizosaccharomyces pombe are functionally conserved in human cells (V. Spataro et al. (1997) J Biol Chem 272: 30470-30475). The human homologue of one of these genes, hCRM1, has recently been identified and found to function in nucleocytoplasmic export, a process which controls the subcellular localization and hence activity of a number of key cell cycle regulators and transcription factors. Several mutant alleles of crm1 confer a phenotype of MDR in S. pombe, through the nuclear accumulation of the AP-1 transcription factor Pap1. We therefore sequenced mutations of crm1 in fission yeast in order to guide the search for analogous hCRM1 mutations which could play a role in tumour-drug resistance. Fifteen yeast crm1 mutants were assessed by PCR and DNA sequencing. Four mis-sense mutations were identified in the open reading frame, three of which (G to A transitions at nucleotide positions 385, 895 and 1,288) were capable of conferring the MDR phenotype alone. For three of the four mutations found, the corresponding amino acid changes affect residues which are conserved in the human homologue hCRM1 and lie in highly conserved regions of the CRM1 protein. We analysed the corresponding hCRM1 coding regions by RT-PCR and sequencing in a panel of ten tumour cell lines, including three ovarian lines resistant either to cisplatin or paclitaxel, or to both and one MDR breast cancer cell line with nuclear accumulation of the transcription factor YB-1. No hCRM1 mutations were found in the three cDNA fragments examined in this panel of tumour cell lines. However, the identification of amino acid residues within the CRM1 protein that are critical for the export of the MDR-associated transcription factor Pap1 in fission yeast can guide further analysis of hCRM1 mutations in tumours with a MDR phenotype.

Asunto(s)

Resistencia a Múltiples Medicamentos/genética , Carioferinas/fisiología , Receptores Citoplasmáticos y Nucleares , Schizosaccharomyces/genética , Secuencia de Aminoácidos , Secuencia de Bases , Sitios de Unión , Proteínas Portadoras/metabolismo , Ciclo Celular , Farmacorresistencia Microbiana/genética , Humanos , Carioferinas/genética , Datos de Secuencia Molecular , Mutación , Proteínas Nucleares/genética , Proteínas Nucleares/fisiología , Proteínas Asociadas a Pancreatitis , Schizosaccharomyces/efectos de los fármacos , Factores de Transcripción/metabolismo , Transcripción Genética , Células Tumorales Cultivadas , Proteína Exportina 1

RESUMEN

Phonological skills, language ability, and literacy scores were compared for four groups: 19 children with mild-to-moderate sensorineural hearing loss (SNH), 20 children with specific language impairment (SLI), 20 controls matched on chronological age to the SNH group (CA), and 15 controls matched on receptive vocabulary level to a subset of the SLI group (CB). In common with the SLI group, mean scores of children with mild-to-moderate hearing loss were significantly poorer on tests of phonological short-term memory, phonological discrimination, and phonological awareness than CA controls. No differences between group means were observed in SNH and CA control groups on vocabulary, digit and sentence recall, sentence comprehension, and literacy scores. However, there was considerable individual variation within the SNH group. Nearly 50% of the SNH group showed phonological impairment associated with poorer expressive and receptive vocabulary and higher hearing thresholds than remaining children without phonological impairment. Nonword repetition deficits were observed in SNH subgroups with and without phonological impairment and were of a similar magnitude to those observed in children with SLI. Indeed, poorer repetition in children with SLI could only be differentiated from children with SNH on phonologically complex nonwords. Overall, findings suggested major problems in nonword repetition and phonological impairment occurred without clinically significant deficits in wider language and literacy abilities in children with mild-to-moderate sensorineural hearing loss. Implications for theories of SLI are discussed.

Asunto(s)

Lenguaje Infantil , Escolaridad , Pérdida Auditiva Sensorineural/diagnóstico , Trastornos del Lenguaje/diagnóstico , Percepción del Habla/fisiología , Umbral Auditivo/fisiología , Niño , Preescolar , Humanos , Comunicación no Verbal , Fonética , Solución de Problemas , Índice de Severidad de la Enfermedad , Pruebas de Discriminación del Habla , Conducta Verbal , Vocabulario

RESUMEN

Cells are constantly under threat from the cytotoxic and mutagenic effects of DNA damaging agents. These agents can either be exogenous or formed within cells. Environmental DNA-damaging agents include UV light and ionizing radiation, as well as a variety of chemicals encountered in foodstuffs, or as air- and water-borne agents. Endogenous damaging agents include methylating species and the reactive oxygen species that arise during respiration. Although diverse responses are elicited in cells following DNA damage, this review focuses on three aspects: DNA repair mechanisms, cell cycle checkpoints, and apoptosis. Because the areas of nucleotide excision repair and mismatch repair have been covered extensively in recent reviews, we restrict our coverage of the DNA repair field to base excision repair and DNA double-strand break repair.

Asunto(s)

Ciclo Celular/fisiología , Daño del ADN/fisiología , Animales , Ciclo Celular/efectos de los fármacos , Muerte Celular/efectos de los fármacos , Muerte Celular/fisiología , ADN/química , ADN/efectos de los fármacos , Reparación del ADN/efectos de los fármacos , Humanos

RESUMEN

Current knowledge of the processing of viral Ags into MHC class I-associated ligands is based almost completely on in vitro studies using nonprofessional APCs (pAPCs). This is two steps removed from real immune responses to pathogens and vaccines, in which pAPCs activate naive CD8(+) T cells in vivo. Rational vaccine design requires answers to numerous questions surrounding the function of pAPCs in vivo, including their abilities to process and present peptides derived from endogenous and exogenous viral Ags. In the present study, we characterize the in vivo dependence of Ag presentation on the expression of TAP by testing the immunogenicity of model Ags synthesized by recombinant vaccinia viruses in TAP1(-/-) mice. We show that the efficiency of TAP-independent presentation in vitro correlates with TAP-independent activation of naive T cells in vivo and provide the first in vivo evidence for proteolytic processing of antigenic peptides in the secretory pathway. There was, however, a clear exception to this correlation; although the presentation of the minimal SIINFEKL determinant from chicken egg OVA in vitro was strictly TAP dependent, it was presented in a TAP-independent manner in vivo. In vivo presentation of the same peptide from a fusion protein retained its TAP dependence. These results show that determinant-specific processing pathways exist in vivo for the generation of antiviral T cell responses. We present additional findings that point to cross-priming as the likely mechanism for these protein-specific differences.

Asunto(s)

Presentación de Antígeno , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Epítopos de Linfocito T/inmunología , Activación de Linfocitos , Transportador de Casetes de Unión a ATP, Subfamilia B, Miembro 2 , Transportadoras de Casetes de Unión a ATP/administración & dosificación , Transportadoras de Casetes de Unión a ATP/biosíntesis , Transportadoras de Casetes de Unión a ATP/genética , Transportadoras de Casetes de Unión a ATP/fisiología , Traslado Adoptivo , Animales , Antígenos Virales/administración & dosificación , Antígenos Virales/genética , Antígenos Virales/inmunología , Antígenos Virales/metabolismo , Linfocitos T CD8-positivos/trasplante , Células Cultivadas , Citotoxicidad Inmunológica/genética , Citotoxicidad Inmunológica/inmunología , Proteínas del Huevo/administración & dosificación , Proteínas del Huevo/genética , Proteínas del Huevo/inmunología , Femenino , Humanos , Inyecciones Intravenosas , Interfase/inmunología , Transfusión de Linfocitos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Ovalbúmina/administración & dosificación , Ovalbúmina/genética , Ovalbúmina/inmunología , Fragmentos de Péptidos/administración & dosificación , Fragmentos de Péptidos/genética , Fragmentos de Péptidos/inmunología , Receptores de Antígenos de Linfocitos T/genética , Receptores de Antígenos de Linfocitos T/inmunología , Proteínas Recombinantes/administración & dosificación , Proteínas Recombinantes/inmunología , Proteínas Recombinantes/metabolismo , Recombinación Genética/inmunología , Virus Vaccinia/genética , Virus Vaccinia/inmunología , Proteínas del Núcleo Viral/administración & dosificación , Proteínas del Núcleo Viral/genética , Proteínas del Núcleo Viral/inmunología

RESUMEN

The performance on production of finite verb morphology of 19 children (ages 5;9-10;7) with mild-moderate sensorineural hearing impairment (SNH) was compared with that of 14 children with specific language impairment (SLI) (ages 7;2-10;9) and age-matched and language-matched control groups. On average, the SNH group outperformed the SLI group and was comparable to controls. However, a subset of the SNH group (n = 6) was impaired on one or both of these tasks. Degree of hearing loss or age of receiving hearing aids was not directly related to performance, but other language measures were. The subset was also significantly younger than the rest of the SNH group, suggesting that acquisition of finite verb morphology may be delayed in children with hearing impairments. Verb regularity had no effect on performance of any group, but word frequency and phonological complexity did exert an influence. The findings are discussed in relation to causative theories of SLI.

Asunto(s)

Lenguaje Infantil , Pérdida Auditiva Sensorineural/diagnóstico , Umbral Auditivo/fisiología , Niño , Humanos , Fonética , Índice de Severidad de la Enfermedad , Aprendizaje Verbal/fisiología

Asunto(s)

Presentación de Antígeno , Células Presentadoras de Antígenos/inmunología , Antígenos/metabolismo , Antígenos de Histocompatibilidad Clase I/inmunología , Amilorida/farmacología , Animales , Células Presentadoras de Antígenos/citología , Cloroquina/farmacología , Citocalasinas/farmacología , Endocitosis/efectos de los fármacos , Endocitosis/fisiología , Fluoresceína-5-Isotiocianato , Células Asesinas Naturales/inmunología , Fagocitosis/efectos de los fármacos , Fagocitosis/fisiología , Sensibilidad y Especificidad , Espectrometría de Fluorescencia/métodos , Linfocitos T/inmunología , Microglobulina beta-2/metabolismo