RESUMEN

BACKGROUND: Effects of beta-amyloid accumulation on neuronal function precede the clinical manifestation of Alzheimer's disease (AD) by years and affect distinct cognitive brain networks. As previous studies suggest a link between beta-amyloid and dysregulation of excitatory and inhibitory neurotransmitters, we aimed to investigate the impact of GABA and glutamate on beta-amyloid related functional connectivity. METHODS: 29 cognitively unimpaired old-aged adults (age = 70.03 ±â€¯5.77 years) were administered 11C-Pittsburgh Compound B (PiB) positron-emission tomography (PET), and MRI at 7 Tesla (7T) including blood oxygen level dependent (BOLD) functional MRI (fMRI) at rest for measuring static and dynamic functional connectivity. An advanced 7T MR spectroscopic imaging (MRSI) sequence based on the free induction decay acquisition localized by outer volume suppression' (FIDLOVS) technology was used for gray matter specific measures of GABA and glutamate in the posterior cingulate and precuneus (PCP) region. RESULTS: GABA and glutamate MR-spectra indicated significantly higher levels in gray matter than in white matter. A global effect of beta-amyloid on functional connectivity in the frontal, occipital and inferior temporal lobes was observable. Interactive effects of beta-amyloid with gray matter GABA displayed positive PCP connectivity to the frontomedial regions, and the interaction of beta-amyloid with gray matter glutamate indicated positive PCP connectivity to frontal and cerebellar regions. Furthermore, decreased whole-brain but increased fronto-occipital and temporo-parietal dynamic connectivity was found, when GABA interacted with regional beta-amyloid deposits in the amygdala, frontal lobe, hippocampus, insula and striatum. CONCLUSIONS: GABA, and less so glutamate, may moderate beta-amyloid related functional connectivity. Additional research is needed to better characterize their interaction and potential impact on AD.

Asunto(s)

Envejecimiento/fisiología , Péptidos beta-Amiloides/metabolismo , Cerebelo/fisiología , Corteza Cerebral/fisiología , Ácido Glutámico/metabolismo , Sustancia Gris/fisiología , Neuroimagen/métodos , Ácido gamma-Aminobutírico/metabolismo , Anciano , Envejecimiento/metabolismo , Compuestos de Anilina , Cerebelo/diagnóstico por imagen , Cerebelo/metabolismo , Corteza Cerebral/diagnóstico por imagen , Corteza Cerebral/metabolismo , Conectoma/métodos , Femenino , Sustancia Gris/diagnóstico por imagen , Sustancia Gris/metabolismo , Humanos , Imagen por Resonancia Magnética/métodos , Espectroscopía de Resonancia Magnética/métodos , Masculino , Tomografía de Emisión de Positrones/métodos , Tiazoles

RESUMEN

Quantification of myofibroblasts is a promising method for assessing tissue properties in the field of fascia research. This is commonly performed by immunohistochemistry for α-smooth muscle actin. However, usually larger tissue samples sizes are required for quantification. The aim of this investigation was to explore whether a microscopic quantification of myofibroblasts can be conducted with fascial tissue samples derived via percutaneous needle biopsy. Fascial tissues were derived via percutaneous needle biopsy from the fascia lata of 11 persons (aged 19-40 years). Following immunohistochemistry, selected fields for photomicroscopic analysis were chosen by a Monte Carlo method based randomization procedure. On these fields, a digital quantification for the relative density of α-smooth muscle actin was attempted. The newly developed quantification method could successfully be applied in all tissue samples. The median α-smooth muscle actin density in the selected tissue samples ranged between 0% and 1.7% (median 0%, IQR 0%-0.001%). The applied protocol proved to be workable for the purpose of an estimation of the α-smooth muscle actin density in fascial tissue samples derived via percutaneous needle biopsy. Since this type of biopsy is less invasive than the commonly performed open muscle biopsy, this offers a new and useful perspective for future histological investigations of fascial tissue properties in living patients. Clin. Anat. 31:368-372, 2018. © 2018 Wiley Periodicals, Inc.

Asunto(s)

Fascia Lata/patología , Miofibroblastos , Biopsia con Aguja , Recuento de Células , Humanos

RESUMEN

AIMS: We compared the clinical and radiological outcomes of using a polyetheretherketone cage with (TiPEEK) and without a titanium coating (PEEK) for instrumented transforaminal lumbar interbody fusion (TLIF). MATERIALS AND METHODS: We conducted a randomised clinical pilot trial of 40 patients who were scheduled to undergo a TLIF procedure at one or two levels between L2 and L5. The Oswestry disability index (ODI), EuroQoL-5D, and back and leg pain were determined pre-operatively, and at three, six, and 12 months post-operatively. Fusion rates were assessed by thin slice CT at three months and by functional radiography at 12 months. RESULTS: At final follow-up, one patient in each group had been lost to follow-up. Two patients in each of the PEEK and TiPEEK groups were revised for pseudarthrosis (p = 1.00). The rate of complete or partial fusion at three months was 91.7% in both groups. Overall, there were no significant differences in ODI or in radiological outcomes between the groups. CONCLUSION: Favourable results with identical clinical outcomes and a high rate of fusion was seen in both groups. The titanium coating appears to have no negative effects on outcome or safety in the short term. A future study to determine the effect of titanium coating is warranted. Cite this article: Bone Joint J 2017;99-B:1366-72.

Asunto(s)

Materiales Biocompatibles Revestidos , Cetonas , Dolor de la Región Lumbar/cirugía , Vértebras Lumbares/cirugía , Polietilenglicoles , Fusión Vertebral/instrumentación , Titanio , Anciano , Benzofenonas , Femenino , Estudios de Seguimiento , Humanos , Masculino , Proyectos Piloto , Polímeros , Diseño de Prótesis , Resultado del Tratamiento

RESUMEN

Quantitative Susceptibility Mapping (QSM) MRI at 7 Tesla and 11-Carbon Pittsburgh-Compound-B PET were used for investigating the relationship between brain iron and Amyloid beta (Aß) plaque-load in a context of increased risk for Alzheimer's disease (AD), as reflected by the Apolipoprotein E ε4 (APOE-e4) allele and mild cognitive impairment (MCI) in elderly subjects. Carriers of APOE-e4 with normal cognition had higher cortical Aß-plaque-load than non-carriers. In MCI an association between APOE-e4 and higher Aß-plaque-load was observable both for cortical and subcortical brain-regions. APOE-e4 and MCI was also associated with higher cortical iron. Moreover, cerebral iron significantly affected functional coupling, and was furthermore associated with increased Aß-plaque-load (R2-adjusted = 0.80, p < 0.001) and APOE-e4 carrier status (p < 0.001) in MCI. This study confirms earlier reports on an association between increased brain iron-burden and risk for neurocognitive dysfunction due to AD, and indicates that disease-progression is conferred by spatial colocalization of brain iron deposits with Aß-plaques.

Asunto(s)

Péptidos beta-Amiloides/metabolismo , Encéfalo/metabolismo , Disfunción Cognitiva/metabolismo , Hierro/metabolismo , Anciano , Anciano de 80 o más Años , Apolipoproteína E4/genética , Encéfalo/patología , Estudios de Casos y Controles , Disfunción Cognitiva/diagnóstico por imagen , Demografía , Femenino , Heterocigoto , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Tamaño de los Órganos , Tomografía de Emisión de Positrones , Corteza Prefrontal/metabolismo , Corteza Prefrontal/patología

RESUMEN

Human adenoviruses (HAdV) are used as a model system to investigate tumorigenic processes in mammalian cells where the viral oncoproteins E1A and E1B-55K are absolutely required for oncogenic transformation, because they simultaneously accelerate cell cycle progression and inhibit tumor suppressor proteins such as p53, although the underlying mechanism is still not understood in detail. In our present study, we provide evidence that E1B-55K binding to the PML-NB component Sp100A apparently has an essential role in regulating adenovirus-mediated transformation processes. Specifically, when this E1B-55K/Sp100A complex recruits p53, Sp100A-induced activation of p53 transcriptional activity is effectively abolished. Hence, Sp100A exhibits tumor-suppressive activity, not only by stabilizing p53 transactivation but also by depressing E1A/E1B-55K-mediated transformation. E1B-55K counteracts this suppressive activity, inducing Sp100A SUMOylation and sequestering the modified cellular factor into the insoluble matrix of the nucleus or into cytoplasmic inclusions. These observations provide novel insights into how E1B-55K modulates cellular determinants to maintain growth-promoting activity during oncogenic processes and lytic infection.

Asunto(s)

Proteínas E1B de Adenovirus/fisiología , Antígenos Nucleares/metabolismo , Autoantígenos/metabolismo , Transformación Celular Viral/fisiología , Proteína p53 Supresora de Tumor/metabolismo , Proteínas E1B de Adenovirus/genética , Transformación Celular Viral/genética , Humanos , Factores de Transcripción/metabolismo , Activación Transcripcional , Transfección , Proteína p53 Supresora de Tumor/genética

RESUMEN

Although modulation of the cellular tumor-suppressor p53 is considered to have the major role in E1A/E1B-55K-mediated tumorigenesis, other promyelocytic leukemia nuclear body (PML-NB)/PML oncogenic domain (POD)-associated factors including SUMO, Mre11, Daxx, as well as the integrity of these nuclear bodies contribute to the transformation process. However, the biochemical consequences and oncogenic alterations of PML-associated E1B-55K by SUMO-dependent PML-IV and PML-V interaction have so far remained elusive. We performed mutational analysis to define a PML interaction motif within the E1B-55K polypeptide. Our results showed that E1B-55K/PML binding is not required for p53, Mre11 and Daxx interaction. We also observed that E1B-55K lacking subnuclear PML localization because of either PML-IV or PML-V-binding deficiency was no longer capable of mediating E1B-55K-dependent SUMOylation of p53, inhibition of p53-mediated transactivation or efficiently transforming primary rodent cells. These results together with the observation that E1B-55K-dependent SUMOylation of p53 is required for efficient cell transformation, provides evidence for the idea that the SUMO ligase activity of the E1B-55K viral oncoprotein is intimately linked to its growth-promoting oncogenic activities.

Asunto(s)

Adenoviridae/genética , Transformación Celular Viral/genética , Leucemia Promielocítica Aguda/genética , Leucemia Promielocítica Aguda/metabolismo , Proteínas Nucleares/metabolismo , Factores de Transcripción/metabolismo , Proteína p53 Supresora de Tumor/antagonistas & inhibidores , Proteínas Supresoras de Tumor/metabolismo , Proteínas E1B de Adenovirus/genética , Proteínas E1B de Adenovirus/metabolismo , Animales , Células HEK293 , Humanos , Mutación , Proteínas Nucleares/genética , Proteína de la Leucemia Promielocítica , Isoformas de Proteínas , Ratas , Factores de Transcripción/genética , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/metabolismo , Proteínas Supresoras de Tumor/genética

RESUMEN

Since the discovery of post-translational modification (PTM) by the small ubiquitin-related modifiers (SUMOs), a multitude of proteins have been described to be reversibly modified, resulting in the alteration of several cellular pathways. Interestingly, various pathogens gain access to this modification system, although the molecular mechanisms and functional consequences are barely understood. We show here that the adenoviral oncoprotein E1B-55K is a substrate of the SUMO conjugation system, which is directly linked to its C-terminal phosphorylation. This regulative connection is indispensable for modulation of the tumor suppressor p53/chromatin-remodeling factor Daxx by E1B-55K and, consequently, its oncogenic potential in primary mammalian cells. In virus infection, E1B-55K PTMs are necessary for localization to viral transcription/replication sites. Furthermore, we identify the E2 enzyme Ubc9 as an interaction partner of E1B-55K, providing a possible molecular explanation for SUMO-dependent modulation of cellular target proteins. In conclusion, these results for the first time provide evidence how E1B-55K PTMs are regulated and subsequently facilitate exploitation of the host cell SUMOylation machinery.

Asunto(s)

Transformación Celular Neoplásica/metabolismo , Proteínas Quinasas/fisiología , Sumoilación/fisiología , Proteínas Virales/metabolismo , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Proteínas Adaptadoras Transductoras de Señales/fisiología , Adenoviridae/genética , Adenoviridae/metabolismo , Secuencia de Aminoácidos , Animales , Animales Recién Nacidos , Transformación Celular Neoplásica/genética , Células Cultivadas , Proteínas Co-Represoras , Células HEK293 , Humanos , Modelos Biológicos , Chaperonas Moleculares , Datos de Secuencia Molecular , Proteínas Nucleares/metabolismo , Proteínas Nucleares/fisiología , Fosforilación/genética , Fosforilación/fisiología , Filogenia , Proteínas Quinasas/metabolismo , Procesamiento Proteico-Postraduccional/genética , Procesamiento Proteico-Postraduccional/fisiología , Ratas , Receptor Cross-Talk/fisiología , Homología de Secuencia de Aminoácido , Sumoilación/genética , Proteína p53 Supresora de Tumor/metabolismo , Proteína p53 Supresora de Tumor/fisiología , Proteínas Virales/química , Proteínas Virales/genética , Proteínas Virales/fisiología

RESUMEN

Despite the compelling clinical needs in enhancing bone regeneration and the potential offered by the field of tissue engineering, the adoption of cell-based bone graft substitutes in clinical practice is limited to date. In fact, no study has yet convincingly demonstrated reproducible clinical performance of tissue-engineered implants and at least equivalent cost-effectiveness compared to the current treatment standards. Here, we propose and discuss how tissue engineering strategies could be evolved towards more efficient solutions, depicting three different experimental paradigms: (i) bioreactor-based production; (ii) intraoperative manufacturing, and (iii) developmental engineering. The described approaches reflect the need to streamline graft manufacturing processes while maintaining the potency of osteoprogenitors and recapitulating the sequence of biological steps occurring during bone development, including vascularization. The need to combine the assessment of efficacy of the different strategies with the understanding of their mechanisms of action in the target regenerative processes is highlighted. This will be crucial to identify the necessary and sufficient set of signals that need to be delivered at the injury or defect site and should thus form the basis to define release criteria for reproducibly effective engineered bone graft substitutes.

Asunto(s)

Trasplante Óseo/métodos , Ingeniería de Tejidos/métodos , Animales , Reactores Biológicos , Regeneración Ósea , Humanos

RESUMEN

Congenital dislocation of the knee (CDK) is a rare deformity presenting itself either as an isolated idiopathic entity or in the context of syndromes like arthrogryposis, myelodysplasia or Larsen syndrome. Patients can be diagnosed clinically after childbirth based on hyperextension of the knee. Confirmation of the diagnosis is done by X-ray or sonography. Many theories concerning the pathogenesis have been proposed since CDK was described; according to recent literature fibrosis and contracture of the m. quadriceps is the most likely reason. Therapy should start as soon as possible after birth, conservatively using redressing casts or operatively in syndromal conditions aiming for reduction. The prognosis concerning re-dislocation is benign; a good outcome was shown for idiopathic CDK.

Asunto(s)

Moldes Quirúrgicos , Diagnóstico por Imagen/métodos , Luxación de la Rodilla/congénito , Luxación de la Rodilla/diagnóstico , Adolescente , Niño , Preescolar , Humanos , Lactante , Recién Nacido , Luxación de la Rodilla/terapia

RESUMEN

The E1B-55K product from human adenovirus is a substrate of the small ubiquitin-related modifier (SUMO)-conjugation system. SUMOylation of E1B-55K is required to transform primary mammalian cells in cooperation with adenovirus E1A and to repress p53 tumour suppressor functions. The biochemical consequences of SUMO1 conjugation of 55K have so far remained elusive. Here, we report that E1B-55K physically interacts with different isoforms of the tumour suppressor protein promyelocytic leukaemia (PML). We show that E1B-55K binds to PML isoforms IV and V in a SUMO1-dependent and -independent manner. Interaction with PML-IV promotes the localization of 55K to PML-containing subnuclear structures (PML-NBs). In virus-infected cells, this process is negatively regulated by other viral proteins, indicating that binding to PML is controlled through reversible SUMOylation in a timely coordinated manner. These results together with earlier work are consistent with the idea that SUMOylation regulates targeting of E1B-55K to PML-NBs, known to control transcriptional regulation, tumour suppression, DNA repair and apoptosis. Furthermore, they suggest that SUMO1-dependent modulation of p53-dependent growth suppression through E1B-55K PML-IV interaction has a key role in adenovirus-mediated cell transformation.

Asunto(s)

Proteínas E1B de Adenovirus/metabolismo , Transformación Celular Viral/fisiología , Proteínas Nucleares/metabolismo , Proteínas Oncogénicas/metabolismo , Proteína SUMO-1/metabolismo , Factores de Transcripción/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Animales , Línea Celular , Técnica del Anticuerpo Fluorescente Indirecta , Expresión Génica , Regulación Neoplásica de la Expresión Génica/fisiología , Humanos , Immunoblotting , Inmunoprecipitación , Proteína de la Leucemia Promielocítica , Unión Proteica , Isoformas de Proteínas/metabolismo , Ratas , Transfección

RESUMEN

BACKGROUND: Adequate uterine contractility and peristalsis are involved in the transport of semen and gametes and in successful embryo implantation. Estrogen and progesterone fluctuate characteristically during the menstrual cycle. It has been suggested that both hormones influence uterine peristalsis in characteristic ways. METHODS: An extracorporeal perfusion model of the swine uterus was used that keeps the uterus in a functional condition and is suitable for the study of physiological questions. The effects of estrogen and progesterone on oxytocin-induced uterine peristalsis were assessed using an intrauterine double-chip microcatheter. RESULTS: Estrogen perfusion was associated with an increase in intrauterine pressure (IUP) in a dose-dependent manner. There was a significant difference between the IUP increase measured in the isthmus uteri and that in the corpus uteri, resulting in a cervico-fundal pressure gradient. Estrogen perfusion resulted in a significantly higher rate of peristaltic waves starting in the isthmus uteri and directed towards the corpus uteri. Progesterone was able to antagonize the estrogen effect in general. CONCLUSIONS: This study demonstrates that estrogen and progesterone have differential effects in the regulation of uterine peristalsis. The present observation shows that estrogen stimulates uterine peristalsis and is able to generate a cervico-fundal direction of peristalsis, whereas progesterone inhibits directed uterine peristalsis.

Asunto(s)

Estradiol/fisiología , Progesterona/fisiología , Contracción Uterina/fisiología , Animales , Femenino , Técnicas In Vitro , Oxitocina/farmacología , Perfusión , Porcinos , Contracción Uterina/efectos de los fármacos , Útero/efectos de los fármacos

RESUMEN

Triglycerides are a promising class of material for the parenteral delivery of drugs and have become the focus of tremendous research efforts in recent years. The aim of this study was to investigate the biocompatibility of glyceroltripalmitate as well as the influence of cholesterol and distearoyl-phosphatidyl-choline (DSPC) on the erosion behavior of the lipid. For these investigations, two in vivo studies were carried out, in which cylindrical matrices of 2 mm diameter were manufactured and subcutaneously implanted in immunocompetent NMRI-mice. After excision of the implants, tissue reactions of the animals as well as changes in the weight, shape and microstructure of the implants were investigated. The triglyceride and cholesterol showed good biocompatibility, as indicated by their minimal encapsulation in connective tissue and the absence of inflammatory reactions. Increasing the levels of phospholipid in the implants, however, led to an increased inflammatory reaction. In contrast to cholesterol, which did not affect erosion, the incorporation of DSPC into the triglyceride matrices led to clearly visible signs of degradation.

Asunto(s)

Materiales Biocompatibles/efectos adversos , Colesterol/efectos adversos , Implantes de Medicamentos , Reacción a Cuerpo Extraño/inducido químicamente , Fosfatidilcolinas/efectos adversos , Triglicéridos/efectos adversos , Animales , Materiales Biocompatibles/química , Materiales Biocompatibles/metabolismo , Biodegradación Ambiental , Colesterol/química , Colesterol/metabolismo , Femenino , Ensayo de Materiales , Ratones , Fosfatidilcolinas/química , Fosfatidilcolinas/metabolismo , Solubilidad , Propiedades de Superficie , Tecnología Farmacéutica , Triglicéridos/química , Triglicéridos/metabolismo

RESUMEN

Chromosomal translocations that fuse the mixed lineage leukemia gene (MLL) to a variety of unrelated partner genes are frequent in pediatric leukemias. The novel combination of genetic material leads to the production of active oncoproteins that depend on the contributions of both constituents. In a search for a common function amongst the diverse group of MLL fusion partners we constructed artificial fusions joining MLL with generic transactivator and repressor domains (acidic blob, GAL4 transactivator domain, Herpes simplex VP16 activation domain, KRAB repressor domain). Of all constructs tested, only MLL-VP16 was able to transform primary bone marrow cells and to induce a block of early myeloid differentiation like an authentic MLL fusion. Interestingly, the transformation capability of the artificial MLL fusions was correlated with the transcriptional potential of the resulting chimeric protein but it was not related to the strength of the isolated transactivation domain that was joined to MLL. These results prove for the first time that a general biological function - transactivation - might be the common denominator of many MLL fusion partners.

Asunto(s)

Proteínas de Unión al ADN/genética , Proto-Oncogenes , Activación Transcripcional/genética , Animales , Línea Celular , Cromosomas Humanos Par 11 , N-Metiltransferasa de Histona-Lisina , Humanos , Ratones , Proteína de la Leucemia Mieloide-Linfoide , ARN Mensajero/genética , Proteínas Recombinantes de Fusión/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Proteínas de Saccharomyces cerevisiae/genética , Factores de Transcripción/genética , Transcripción Genética , Transfección , Translocación Genética

RESUMEN

The application of x-ray diagnostics for intraoperative navigation and for registration of hard tissue structures is restrained due to high radiation loads and the not given real time ability. Previous approaches with conventional ultrasonic imaging are only interactively applicable due to the high information content of soft tissue optimised B-mode-images. A pure image processing does not allow an automatic identification of individual structures, so that this must be done by the physician. To decrease the high expense of time, this report presents a concept for an adapted chain of rf-signal processing as well as an ultrasonic system for the contrast-enhanced representation of tissue borders. The system permits an exact measurement of the body geometry, which is demonstrated by determining the position of the pelvis entry plane.

Asunto(s)

Artroplastia de Reemplazo de Cadera/instrumentación , Procesamiento Automatizado de Datos/métodos , Interpretación de Imagen Asistida por Computador/instrumentación , Procedimientos Ortopédicos/instrumentación , Cirugía Asistida por Computador/instrumentación , Ultrasonografía/instrumentación , Heridas y Lesiones/cirugía , Algoritmos , Análisis de Fourier , Humanos

RESUMEN

As alternatives to surgical resection and/or supportive to radio- or chemo-therapy of tumors and metastases minimal invasive interstitial thermal treatment procedures by which the tissue is heated up locally to temperatures up to 100 degrees C are used. However beside nuclear magnetic resonance tomography there is no economical, by routine applicable procedure for non invasive therapy control at present disposal. In this work the possibility of non invasive control of thermal therapies by means of temporal and spectral analysis of radio frequency ultrasound signals are evaluated. Two different ultrasonic procedures, the first beeing based on the analysis of local modifications in the time of flight of the ultrasound signal for determination of the temperature distribution in the tissue, the second beeing based on the physical attenuation characteristics of biological tissue and their dependence on the tissue structure are proposed and evaluated for therapy control. With in vitro experiments the possibilities and limitations of both procedures and preliminary results of a prototype control system are demonstrated.

Asunto(s)

Hipertermia Inducida/instrumentación , Procesamiento de Imagen Asistido por Computador/instrumentación , Terapia Asistida por Computador/instrumentación , Ultrasonografía/instrumentación , Animales , Sistemas de Computación , Procesamiento Automatizado de Datos , Análisis de Fourier , Humanos , Hígado/diagnóstico por imagen , Hígado/patología , Necrosis , Porcinos , Temperatura

RESUMEN

Acridone synthase (ACS) and chalcone synthase (CHS) catalyse the pivotal reactions in the formation of acridone alkaloids or flavonoids. While acridone alkaloids are confined almost exclusively to the Rutaceae, flavonoids occur abundantly in all seed-bearing plants. ACSs and CHSs had been cloned from Ruta graveolens and shown to be closely related polyketide synthases which use N-methylanthraniloyl-CoA and 4-coumaroyl-CoA, respectively, as the starter substrate to produce the acridone or naringenin chalcone. As proposed for the related 2-pyrone synthase from Gerbera, the differential substrate specificities of ACS and CHS might be attributed to the relative volume of the active site cavities. The primary sequences as well as the immunological cross reactivities and molecular modeling studies suggested an almost identical spatial structure for ACS and CHS. Based on the Ruta ACS2 model the residues Ser132, Ala133 and Val265 were assumed to play a critical role in substrate specificity. Exchange of a single amino acid (Val265Phe) reduced the catalytic activity by about 75% but grossly shifted the specificity towards CHS activity, and site-directed mutagenesis replacing all three residues by the corresponding amino acids present in CHS (Ser132Thr, Ala133Ser and Val265Phe) fully transformed the enzyme to a functional CHS with comparatively marginal ACS activity. The results suggested that ACS divergently has evolved from CHS by very few amino acid exchanges, and it remains to be established why this route of functional diversity has developed in the Rutaceae only.

Asunto(s)

Aciltransferasas/genética , Aciltransferasas/metabolismo , Evolución Molecular Dirigida , Rutaceae/enzimología , Aciltransferasas/química , Secuencia de Aminoácidos , Sustitución de Aminoácidos , Sitios de Unión , Catálisis , Clonación Molecular , Evolución Molecular , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Conformación Proteica , Pliegue de Proteína , Especificidad por Sustrato

RESUMEN

The translocation t(11;19) is a recurrent feature of a subgroup of acute leukemias occurring in infants. This event fuses the genes MLL and ENL and creates the leukemogenic oncoprotein MLL-ENL. We studied the effect of retroviral MLL-ENL expression in primary mouse hematopoietic cells and show here that MLL-ENL requires the oncoprotein Myc to establish a reversible differentiation arrest of a myelomonocytic precursor population. MLL-ENL-transduced cells proliferated as immature myeloid cells in the presence of interleukin 3. The addition of granulocyte colony-stimulating factor reversed the maturation block set by MLL-ENL and induced the development of mature granulocytes and macrophages accompanied by growth arrest. Gene expression analysis indicated a down-regulation of the proto-oncogene c-myc and of several c-myc target genes during granulocyte colony-stimulating factor-mediated differentiation. The role of c-myc in the MLL-ENL transformation pathway was tested by modulating the effective Myc protein concentrations in MLL-ENL transduced cells. Cotransduction of dominant-negative Myc neutralized the MLL-ENL effect and precluded transformation. In contrast, constitutive expression of Myc cooperated with MLL-ENL and caused the transformation of a cell population with an irreversible maturation arrest.

Asunto(s)

Transformación Celular Neoplásica/genética , Genes myc/fisiología , Células Madre Hematopoyéticas/citología , Proteínas de Fusión Oncogénica/fisiología , Animales , Apoptosis/efectos de los fármacos , Apoptosis/fisiología , Diferenciación Celular/efectos de los fármacos , Diferenciación Celular/genética , Diferenciación Celular/fisiología , Transformación Celular Neoplásica/patología , Regulación de la Expresión Génica , Factor Estimulante de Colonias de Granulocitos/farmacología , Interleucina-3/farmacología , Leucemia/genética , Leucemia/patología , Ratones , Ratones Endogámicos BALB C , Proteína de la Leucemia Mieloide-Linfoide , Proteínas de Fusión Oncogénica/biosíntesis , Proteínas de Fusión Oncogénica/genética , Proto-Oncogenes Mas , Proteínas Proto-Oncogénicas c-myc/biosíntesis , Proteínas Proto-Oncogénicas c-myc/fisiología , Retroviridae/genética , Transducción Genética

RESUMEN

The translocation t(11;19) is frequently found in acute leukemia in infants. This event truncates the proto-oncogene MLL and fuses the 5' end of MLL in frame with the ENL gene. ENL contributes a crucial protein-protein interaction domain to the resulting oncoprotein MLL-ENL. Here we show by yeast two-hybrid assays, GST-pull-down experiments and in a far western blot analysis that this domain is necessary and sufficient to recruit a novel member of the human Polycomb protein family (hPc3). hPc3 RNA was detected throughout the human hematopoietic system. Similar to other Polycomb proteins hPc3 acts as a transcriptional repressor. The ENL-hPc3 interaction was verified by mutual co-precipitation of the proteins from cell extracts. ENL and hPc3 tagged with fluorescent proteins co-localized in living cells in a nuclear dot pattern. An internal region of hPc3 was responsible for binding to ENL. Finally, hPc3 binds to the C-terminus of AF9, another common MLL fusion partner. The recruitment of a repressive function by ENL opens up a new insight into a possible mechanism of leukemogenesis by the fusion protein MLL-ENL.

Asunto(s)

Proteínas de Unión al ADN/metabolismo , Leucemia/etiología , Proteínas de Neoplasias , Proteínas Nucleares/metabolismo , Proteínas de Fusión Oncogénica/metabolismo , Proto-Oncogenes , Proteínas Represoras/metabolismo , Factores de Transcripción , Secuencia de Aminoácidos , Sitios de Unión , Western Blotting , Compartimento Celular , Proteínas de Unión al ADN/genética , N-Metiltransferasa de Histona-Lisina , Humanos , Lactante , Datos de Secuencia Molecular , Proteína de la Leucemia Mieloide-Linfoide , Proteínas Nucleares/genética , Proteínas del Grupo Polycomb , Pruebas de Precipitina , Unión Proteica , Estructura Terciaria de Proteína , Proto-Oncogenes Mas , Homología de Secuencia de Aminoácido , Translocación Genética , Técnicas del Sistema de Dos Híbridos

RESUMEN

A 62-year-old woman presented with episodic sweating and shivering with reduced core temperature. Brain MRI demonstrated a basal forebrain malformation. Physiologic testing included EEG, SPECT, heat challenge, and autonomic testing. Glycopyrrolate aborted spells and raised core temperature. Hypothalamic dysregulation is likely the primary pathophysiology in the setting of other forebrain anomalies. These findings expand the structural abnormalities and treatment options within the temperature dysregulating conditions of Shapiro's syndrome and "diencephalic epilepsy."

Asunto(s)

Hiperhidrosis/patología , Hipotermia/patología , Prosencéfalo/anomalías , Prosencéfalo/patología , Femenino , Humanos , Persona de Mediana Edad , Síndrome

RESUMEN

We performed visual comparison of 200 head magnetic resonance (MR) and 200 head computed tomography (CT) images compressed at two levels using standard Joint Photographic Experts Group (JPEG) irreversible compression and a preliminary version of the JPEG 2000 irreversible algorithm. Blinded evaluations by neuroradiologists compared original versus either JPEG or JPEG 2000. We found that this version of JPEG 2000 did not perform as well as the current JPEG for head CTs, but for MR images, JPEG 2000 performed as well or better. Around 7:1 compression ratio seemed to be a conservative point where there was no perceptible difference.

Asunto(s)

Algoritmos , Imagen por Resonancia Magnética/instrumentación , Neurorradiografía/instrumentación , Sistemas de Información Radiológica/instrumentación , Tomografía Computarizada por Rayos X/instrumentación , Humanos , Control de Calidad