RESUMEN
BACKGROUND: Brainstem electric response audiometries (BERA) are in clinical use for a number of years. The aim of our study was to evaluate data regarding the long-term reliability of BERA-determined frequency specific thresholds in hearing disabled children. MATERIAL AND METHODS: In a group of 97 hearing disabled children we sought to compare Notched-Noise- (NN) BERA threshold as well as Click-BERA thresholds taken shortly after birth with behavioral audiometry thresholds determined after 3.2 years (mean). RESULTS: We found a significant correlation between both BERA methods and the behavioral tests. However, the correlation coefficients for NN-BERA were higher than for Click-BERA thresholds. CONCLUSION: Our results provide evidence for a high reliability of the NN-BERA for characterization of early onset hearing disabilities in children. Our data suggest that pathologic findings in the Click-BERA should always be followed by a frequency specific analysis with NN-BERA.
Asunto(s)
Umbral Auditivo/fisiología , Tronco Encefálico/fisiopatología , Potenciales Evocados Auditivos del Tronco Encefálico/fisiología , Pérdida Auditiva Conductiva/diagnóstico , Pérdida Auditiva Conductiva/fisiopatología , Perdida Auditiva Conductiva-Sensorineural Mixta/diagnóstico , Pérdida Auditiva Sensorineural/diagnóstico , Pérdida Auditiva Sensorineural/fisiopatología , Percepción de la Altura Tonal/fisiología , Estimulación Acústica/métodos , Audiometría/métodos , Preescolar , Femenino , Estudios de Seguimiento , Perdida Auditiva Conductiva-Sensorineural Mixta/fisiopatología , Humanos , Lactante , Recién Nacido , Masculino , Valor Predictivo de las Pruebas , Estudios RetrospectivosAsunto(s)
Enfermedades de las Encías/diagnóstico por imagen , Enfermedades Maxilares/diagnóstico por imagen , Melanoma/diagnóstico , Neoplasias de la Boca/diagnóstico , Trastornos de la Pigmentación/diagnóstico , Neoplasias Cutáneas/diagnóstico , Diagnóstico Diferencial , Enfermedades de las Encías/patología , Enfermedades de las Encías/terapia , Humanos , Masculino , Enfermedades Maxilares/patología , Enfermedades Maxilares/terapia , Melanoma/patología , Melanoma/terapia , Persona de Mediana Edad , Neoplasias de la Boca/patología , Neoplasias de la Boca/terapia , Trastornos de la Pigmentación/patología , Trastornos de la Pigmentación/terapia , Neoplasias Cutáneas/patología , Neoplasias Cutáneas/terapia , Resultado del TratamientoRESUMEN
Hodgkin lymphoma (HL) is the most frequent nodal lymphoma in Europe. The B-cell derived Hodgkin-Reed Sternberg (HRS) cells are nearly completely deficient for expression of B-cell markers. Epstein-Barr virus (EBV) can be detected in about 40% of HL cases. Presumably, EBV protects HRS cell precursors from apoptosis. Histologically only single HRS cells are dispersed in a broad reactive cellular background. Interactions between HRS cells and their surrounding cellular infiltrate, among them paracrine activation of several signalling pathways, is crucial in HL. HRS cells also show autocrine activation of several signalling pathways. Among these, the aberrant expression and activation of seven different receptor tyrosine kinases (RTK) is of special interest, as many different antibodies and low molecular substances which inhibit RTK activity are already in clinical use for anticancer therapy. Therefore, blocking of RTK activities in HL may be a novel therapeutic option.
Asunto(s)
Antineoplásicos/uso terapéutico , Enfermedad de Hodgkin/genética , Enfermedad de Hodgkin/patología , Piperazinas/uso terapéutico , Pirimidinas/uso terapéutico , Proteínas Tirosina Quinasas Receptoras/antagonistas & inhibidores , Proteínas Tirosina Quinasas Receptoras/genética , Comunicación Autocrina/genética , Linfocitos B/patología , Benzamidas , Biopsia , Línea Celular Tumoral , Análisis Mutacional de ADN , Infecciones por Virus de Epstein-Barr/tratamiento farmacológico , Infecciones por Virus de Epstein-Barr/genética , Infecciones por Virus de Epstein-Barr/patología , Enfermedad de Hodgkin/tratamiento farmacológico , Humanos , Mesilato de Imatinib , Ganglios Linfáticos/patología , Comunicación Paracrina/genética , Células de Reed-Sternberg/patología , Transducción de Señal/genética , Linfocitos T/patología , Transcripción Genética/genéticaRESUMEN
Mediastinal large B-cell (MBL) and classical Hodgkin lymphoma (HL) have several pathogenic mechanisms in common. As we recently observed aberrant tyrosine kinase (TK) activities in HL, we now analysed also MBL for such activities. Indeed, MBL and HL were the only B-cell lymphomas where elevated cellular phospho-tyrosine contents were typical features. Three TKs, JAK2, RON and TIE1, not expressed in normal B cells, were each expressed in about 30% of MBL cases, and 75% of cases expressed at least one of the TKs. Among the intracellular pathways frequently triggered by TKs, the PI3K/AKT pathway was activated in about 40% of MBLs and essential for survival of MBL cell lines, whereas the RAF/mitogen-activated protein kinase pathway seemed to be inhibited. No activating mutations were detected in the three TKs in MBL cell lines and primary cases. RON and TIE1 were each also expressed in about 35% and JAK2 in about 53% of HL cases. JAK2 genomic gains are frequent in MBL and HL but we observed no strict correlation of JAK2 genomic status with JAK2 protein expression. In conclusion, aberrant TK activities are a further shared pathogenic mechanism of MBL and HL and may be interesting targets for therapeutic intervention.
Asunto(s)
Regulación Neoplásica de la Expresión Génica , Enfermedad de Hodgkin/genética , Linfoma de Células B/genética , Proteína Oncogénica v-akt/genética , Fosfatidilinositol 3-Quinasas/genética , Proteínas Tirosina Quinasas/genética , Activación Enzimática , Regulación Enzimológica de la Expresión Génica , Enfermedad de Hodgkin/clasificación , Enfermedad de Hodgkin/enzimología , Humanos , Linfoma de Células B/clasificación , Linfoma de Células B/enzimología , Linfoma de Células B Grandes Difuso/enzimología , Linfoma de Células B Grandes Difuso/genética , Proteína Oncogénica v-akt/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Tirosina Quinasas/metabolismoRESUMEN
Clonally related composite lymphomas of Hodgkin's lymphoma (HL) and Non-Hodgkin's lymphoma (NHL) represent models to study the multistep transformation process in tumorigenesis and the development of two distinct tumors from a shared precursor. We analyzed six such lymphomas for transforming events. The HLs were combined in two cases with follicular lymphoma (FL), and in one case each with B-cell chronic lymphocytic leukemia, splenic marginal zone lymphoma, mantle cell lymphoma (MCL) and diffuse large B-cell lymphoma (DLBCL). In the HL/FL and HL/MCL combinations, BCL2/IGH and CCND1/IGH translocations, respectively, were detected in both the HL and NHL. No mutations were found in the tumor suppressor genes FAS, NFKBIA and ATM. The HL/DLBCL case harbored clonal replacement mutations of the TP53 gene on both alleles exclusively in the DLBCL. In conclusion, we present the first examples of molecularly verified IgH-associated translocations in HL, which also show that BCL2/IGH or CCND1/IGH translocations can represent early steps in the pathogenesis of composite HL/FL or HL/MCL. The restriction of the TP53 mutations to the DLBCL in the HL/DLBCL case exemplifies a late transforming event that presumably happened in the germinal center and affected the fate of a common lymphoma precursor cell towards development of a DLBCL.
Asunto(s)
Transformación Celular Neoplásica/genética , Genes Supresores de Tumor , Cadenas Pesadas de Inmunoglobulina/genética , Linfoma/patología , Mutación , Translocación Genética , Transformación Celular Neoplásica/patología , Células Clonales , Ciclina D1/genética , Genes bcl-2 , Enfermedad de Hodgkin/patología , Humanos , Linfoma/etiología , Linfoma/genética , Linfoma no Hodgkin/patología , Proteína p53 Supresora de Tumor/genéticaRESUMEN
A novel triterpenoid saponin 3-O-ß-D-glucuronopyranosyl-(1' --> 3)-2α,19α-dihydroxyolean-12-en-28-oic acid [3-O-ß-D-glucuronopyranosyl-(1' --> 3)-arjunic acid, 1], ten known compounds [six triterpenoids: α-amyrin (2), ß-amyrin (3), germanicol (4), lupeol (5), friedelin (6), friedelanol (7); four steroids--campesterol (8), stigmasterol (9), sitosterol (10), cholesterol (11)], and a long chain alcohol n-eicosan-1-ol (12) were identified in the bark of Lecythis pisonis. The structures were established by 1D and 2D NMR spectroscopy (1H and 13C-NMR, DEPTQ, 1H-1H-COSY, NOESY, HSQC and HMBC), low (CG-MS) and high resolution mass spectrometry (HR-ESI-MS), and infrared (IR) spectral data involving comparison with the literature.
Asunto(s)
Lecythidaceae/química , Extractos Vegetales/química , Saponinas/química , Espectroscopía de Resonancia Magnética , Estructura MolecularRESUMEN
Signal transduction in response to interleukin-6 (IL-6) results from homodimerization of gp130. This dimerization occurs after binding of IL-6 to its surface receptor (IL-6R) and can also be triggered by the complex of soluble IL-6R and IL-6. We fused IL-6 to the constant region of a human IgG1 heavy chain (Fc). IL-6Fc was expressed in COS-7 cells and purified via Protein A Sepharose. Using three different assays we found that the biological activity of this dimeric IL-6 protein is comparable with monomeric IL-6. Recently, we described the designer cytokine Hyper-IL-6 (H-IL-6) in which soluble IL-6R and IL-6 are connected via a flexible peptide linker. This molecule turned out to be 100-1000 times more effective than unlinked IL-6 and soluble IL-6R. Hyper-IL-6 acts on cells only expressing gp130 and is a potent stimulator of in vitro expansion of early hematopoietic precursors. Here we show that a Fc fusion protein of H-IL-6 (H-IL-6Fc) has the same biological activity on BAF/gp130 cells as H-IL-6. Furthermore, both H-IL-6 forms have a similar ability to induce the synthesis of acute phase proteins in human hepatoma cells HepG2 and in mice in vivo. The introduction of a thrombin cleavage site between H-IL-6 and the Fc portion of H-IL-6Fc made it possible to specifically recover biologically active monomeric H-IL-6 by limited proteolysis of the fusion protein. A more general use of cleavable immunoadhesins expressed in mammalian cells is discussed.
Asunto(s)
Interleucina-6/biosíntesis , Receptores de Interleucina-6/biosíntesis , Proteínas Recombinantes de Fusión/biosíntesis , Animales , Células COS , Carcinoma Hepatocelular , Dimerización , Humanos , Hidrólisis , Fragmentos Fc de Inmunoglobulinas/biosíntesis , Fragmentos Fc de Inmunoglobulinas/genética , Fragmentos Fc de Inmunoglobulinas/aislamiento & purificación , Inmunoglobulina G , Cadenas Pesadas de Inmunoglobulina/biosíntesis , Cadenas Pesadas de Inmunoglobulina/genética , Interleucina-6/genética , Interleucina-6/aislamiento & purificación , Ratones , Ingeniería de Proteínas , Receptores de Interleucina-6/genética , Receptores de Interleucina-6/aislamiento & purificación , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/aislamiento & purificación , Trombina/metabolismo , Células Tumorales CultivadasRESUMEN
In Experiment I, four children with asthma were taught to use the intermittent positive-pressure breathing (IPPB) apparatus, a device that delivers bronchodilator medication to the lungs under positive pressure. Because these youngsters had not learned to use the device with repeated instructions, script with back-up reinforcement was introduced to train sequentially three responses - eye fixation, facial posturing, and diaphragmatic breathing - according to a multiple-baseline design. The procedures were effective in teaching appropriate use of the IPPB apparatus. Further, the children's use of the apparatus after training resulted in significantly more effective relief of asthma symptoms. In a second experiment, nurses were instructed in the application of the operant techniques used in the first study, and then served as experimenters in a partial replication of Experiment I. The data once again reflected a strong impact of the intervention program on IPPB responses.
Asunto(s)
Asma/terapia , Terapia Conductista , Respiración con Presión Positiva Intermitente , Respiración con Presión Positiva , Ejercicios Respiratorios , Preescolar , Condicionamiento Operante , Diafragma/fisiología , Femenino , Fijación Ocular , Generalización Psicológica , Humanos , Masculino , Enfermeras y Enfermeros/estadística & datos numéricos , Postura , RecompensaRESUMEN
Haematuria is the most common clinical symptom of bladder cancer. Besides antibiotic treatment of a probably existing urinary tract infection, ultrasonography of the urinary organs, diagnostic cystoscopy (with biopsy if needed), and radiologic evaluation of the upper urinary tract (intravenous urography, computed tomography or magnetic resonance urography, retrograde pyelography) should be done for further evaluation. Atypical manifestations of systemic diseases with bladder infiltration could feign the clinical appearance of chronic cystitis and hinder determination of the correct diagnosis. The case of a 40-year-old man with recurrent gross haematuria due to extremely rare bladder infiltration through an IgM plasmacytoma is presented.
Asunto(s)
Hematuria/etiología , Inmunoglobulina M/análisis , Cadenas kappa de Inmunoglobulina/análisis , Plasmacitoma/diagnóstico , Neoplasias de la Vejiga Urinaria/diagnóstico , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Biopsia , Médula Ósea/patología , Quimioterapia Adyuvante , Cistoscopía , Diagnóstico Diferencial , Hematuria/patología , Hematuria/cirugía , Humanos , Masculino , Estadificación de Neoplasias , Células Plasmáticas/patología , Plasmacitoma/tratamiento farmacológico , Plasmacitoma/patología , Plasmacitoma/cirugía , Vejiga Urinaria/patología , Vejiga Urinaria/cirugía , Neoplasias de la Vejiga Urinaria/tratamiento farmacológico , Neoplasias de la Vejiga Urinaria/patología , Neoplasias de la Vejiga Urinaria/cirugía , Trastornos Urinarios/etiología , Trastornos Urinarios/patología , Trastornos Urinarios/cirugíaRESUMEN
Myosin V is a double-headed molecular motor involved in organelle transport. Two distinctive features of this motor, processivity and the ability to take extended linear steps of approximately 36 nm along the actin helical track, depend on its unusually long light chain-binding domain (LCBD). The LCBD of myosin V consists of six tandem IQ motifs, which constitute the binding sites for calmodulin (CaM) and CaM-like light chains. Here, we report the 2-A resolution crystal structure of myosin light chain 1 (Mlc1p) bound to the IQ2-IQ3 fragment of Myo2p, a myosin V from Saccharomyces cerevisiae. This structure, combined with FRET distance measurements between probes in various CaM-IQ complexes, comparative sequence analysis, and the previously determined structures of Mlc1p-IQ2 and Mlc1p-IQ4, allowed building a model of the LCBD of myosin V. The IQs of myosin V are distributed into three pairs. There appear to be specific cooperative interactions between light chains within each IQ pair, but little or no interaction between pairs, providing flexibility at their junctions. The second and third IQ pairs each present a light chain, whether CaM or a CaM-related molecule, bound in a noncanonical extended conformation in which the N-lobe does not interact with the IQ motif. The resulting free N-lobes may engage in protein-protein interactions. The extended conformation is characteristic of the single IQ of myosin VI and is common throughout the myosin superfamily. The model points to a prominent role of the LCBD in the function, regulation, and molecular interactions of myosin V.
Asunto(s)
Cadenas Pesadas de Miosina/química , Cadenas Pesadas de Miosina/metabolismo , Cadenas Ligeras de Miosina/química , Cadenas Ligeras de Miosina/metabolismo , Miosina Tipo V/química , Miosina Tipo V/metabolismo , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/química , Secuencia de Aminoácidos , Animales , Sitios de Unión , Calmodulina/química , Calmodulina/metabolismo , Cristalografía por Rayos X , Transferencia Resonante de Energía de Fluorescencia , Humanos , Modelos Moleculares , Datos de Secuencia Molecular , Unión Proteica , Estructura Terciaria de Proteína , Alineación de SecuenciaRESUMEN
The interleukin-6-type family of cytokines bind to receptor complexes that share gp130 as a common signal-transducing subunit. So far, receptor antagonists for interleukin-6-type cytokines have been constructed that still bind to the specific ligand binding subunit of the receptor complex, but have lost the ability to stimulate gp130. Such receptor antagonists compete for a specific receptor of a member of the cytokine family. Interleukin-6 only binds to gp130 when complexed with the interleukin-6 receptor that exists as a membrane bound and soluble molecule. Here we have constructed fusion proteins that consist of the soluble form of the human interleukin-6 receptor covalently linked to interleukin-6 receptor antagonists. These fusion proteins directly bind to gp130. Moreover, at concentrations of 10-50 nM they completely neutralize not only the biological activity of interleukin-6 but also of other cytokines of the interleukin-6-type family that act via gp130 homodimers or gp130/LIF-R heterodimers. Therefore, these gp130 targeting cytokine antagonists might be useful therapeutic tools in disease states that are related to cytokines of the interleukin-6 family.
Asunto(s)
Antígenos CD/metabolismo , Citocinas/antagonistas & inhibidores , Glicoproteínas de Membrana/metabolismo , Receptores de Interleucina-6/antagonistas & inhibidores , Receptores de Interleucina-6/metabolismo , Factor Neurotrófico Ciliar , Receptor gp130 de Citocinas , Relación Dosis-Respuesta a Droga , Inhibidores de Crecimiento/farmacología , Humanos , Interleucina-6/genética , Factor Inhibidor de Leucemia , Linfocinas/farmacología , Proteínas del Tejido Nervioso/farmacología , Oncostatina M , Péptidos/farmacología , Mutación Puntual , Unión Proteica , Proteínas Recombinantes de Fusión/farmacologíaRESUMEN
Interleukin-6 (IL-6) and ciliary neurotrophic factor (CNTF) are "4-helical bundle" cytokines of the IL-6 type family of neuropoietic and hematopoietic cytokines. IL-6 signals by induction of a gp130 homodimer (e.g. IL-6), whereas CNTF and leukemia inhibitory factor (LIF) signal via a heterodimer of gp130 and LIF receptor (LIFR). Despite binding to the same receptor component (gp130) and a similar protein structure, IL-6 and CNTF share only 6% sequence identity. Using molecular modeling we defined a putative LIFR binding epitope on CNTF that consists of three distinct regions (C-terminal A-helix/N-terminal AB loop, BC loop, C-terminal CD-loop/N-terminal D-helix). A corresponding gp130-binding site on IL-6 was exchanged with this epitope. The resulting IL-6/CNTF chimera lost the capacity to signal via gp130 on cells without LIFR, but acquired the ability to signal via the gp130/LIFR heterodimer and STAT3 on responsive cells. Besides identifying a specific LIFR binding epitope on CNTF, our results suggest that receptor recognition sites of cytokines are organized as modules that are exchangeable even between cytokines with limited sequence homology.
Asunto(s)
Inhibidores de Crecimiento , Interleucina-6/metabolismo , Linfocinas/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Receptores de Citocinas/metabolismo , Animales , Sitios de Unión , Células COS , Factor Neurotrófico Ciliar , Epítopos/química , Epítopos/metabolismo , Humanos , Interleucina-6/química , Factor Inhibidor de Leucemia , Subunidad alfa del Receptor del Factor Inhibidor de Leucemia , Modelos Moleculares , Proteínas del Tejido Nervioso/química , Fosforilación , Conformación Proteica , Receptores OSM-LIF , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/metabolismo , Células Tumorales CultivadasRESUMEN
IQ motifs are widespread in nature. Mlc1p is a calmodulin-like myosin light chain that binds to IQ motifs of a class V myosin, Myo2p, and an IQGAP-related protein, Iqg1p, playing a role in polarized growth and cytokinesis in Saccharomyces cerevisiae. The crystal structures of Mlc1p bound to IQ2 and IQ4 of Myo2p differ dramatically. When bound to IQ2, Mlc1p adopts a compact conformation in which both the N- and C-lobes interact with the IQ motif. However, in the complex with IQ4, the N-lobe no longer interacts with the IQ motif, resulting in an extended conformation of Mlc1p. The two light chain structures relate to two distinct subfamilies of IQ motifs, one of which does not interact with the N-lobes of calmodulin-like light chains. The correlation between light chain structure and IQ sequence is demonstrated further by sedimentation velocity analysis of complexes of Mlc1p with IQ motifs from Myo2p and Iqg1p. The resulting 'free' N-lobes of myosin light chains in the extended conformation could mediate the formation of ternary complexes during protein localization and/or partner recruitment.
Asunto(s)
Cadenas Ligeras de Miosina/química , Conformación Proteica , Proteínas de Saccharomyces cerevisiae/química , Secuencias de Aminoácidos , Secuencia de Aminoácidos , Animales , Sitios de Unión , Cristalografía por Rayos X , Modelos Moleculares , Datos de Secuencia Molecular , Cadenas Pesadas de Miosina/química , Cadenas Pesadas de Miosina/metabolismo , Cadenas Ligeras de Miosina/metabolismo , Miosina Tipo V/química , Miosina Tipo V/metabolismo , Unión Proteica , Proteínas de Saccharomyces cerevisiae/metabolismo , Alineación de SecuenciaRESUMEN
Mlc1p is a calmodulin-like protein from the budding yeast Saccharomyces cerevisiae, where it has been identified as a subunit of a class V myosin, Myo2p, and a binding partner of an IQGAP-like protein, Iqg1p. Through its interactions with these two proteins, Mlc1p plays a role in polarized growth and cytokinesis. Mlc1p has been crystallized in complexes with four different IQ target motifs from the neck region of Myo2p: IQ2, IQ3, IQ4 and IQ2-IQ3 (referred to as IQ2,3). Electron-density maps for two of the complexes (Mlc1p-IQ4 and Mlc1p-IQ2,3) were obtained from multiple anomalous dispersion (MAD) experiments based on selenomethionine derivatives. The other two structures (Mlc1p-IQ2 and Mlc1p-IQ3) were determined by molecular replacement using the partially refined structure of Mlc1p-IQ2,3 as a search model.