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PURPOSE: The aim of this study was to determine the prevalence of distress and unmet supportive care needs in post-treatment colorectal cancer (CRC) survivors. Also, to explore the association between both variables and to identify potential associated sociodemographic and cancer-related risk factors. METHODS: A cross-sectional study of 200 CRC survivors who at least 1 month before had completed the primary treatment for CRC was conducted. The Brief Symptom Inventory-18 (BSI-18) and the Spanish version of Cancer Survivors' Unmet Needs (S-CaSUN) were used. RESULTS: One in five CRC survivors showed clinical distress and 86% expressed at least one unmet need. Distress was positively associated with the prevalence of needs in all domains. All comprehensive care and information needs were expressed by at least 20% of survivors and some by more than 50%. Other needs also mentioned by 20% of survivors were financial support, ongoing case manager, and concerns about cancer recurrence. The risk factors associated were lower socioeconomic status, younger age, and a primary treatment that includes more than surgery. CONCLUSIONS: The findings highlight the relevance of extending psychosocial care beyond the CRC primary medical treatment. A person-centered approach that addresses informational, emotional, social, and physical needs can increase satisfaction with care and also prevent psychological morbidity in CRC survivors.
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Neoplasias Colorrectales , Calidad de Vida , Neoplasias Colorrectales/epidemiología , Neoplasias Colorrectales/terapia , Estudios Transversales , Necesidades y Demandas de Servicios de Salud , Humanos , Prevalencia , Encuestas y CuestionariosRESUMEN
Significance Statement: The extracellular protein Reelin has an important role in neurological diseases, including epilepsy, Alzheimer's disease and psychiatric diseases, targeting hippocampal circuits. Here we address the role of Reelin in the development of synaptic contacts in adult-generated granule cells (GCs), a neuronal population that is crucial for learning and memory and implicated in neurological and psychiatric diseases. We found that the Reelin pathway controls the shapes, sizes, and types of dendritic spines, the complexity of multisynaptic innervations and the degree of the perisynaptic astroglial ensheathment that controls synaptic homeostasis. These findings show a pivotal role of Reelin in GC synaptogenesis and provide a foundation for structural circuit alterations caused by Reelin deregulation that may occur in neurological and psychiatric disorders.
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Encéfalo/citología , Moléculas de Adhesión Celular Neuronal/metabolismo , Espinas Dendríticas/metabolismo , Proteínas de la Matriz Extracelular/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Neurogénesis/fisiología , Neuroglía/fisiología , Neuronas/fisiología , Serina Endopeptidasas/metabolismo , Sinapsis/fisiología , Animales , Moléculas de Adhesión Celular Neuronal/genética , Diferenciación Celular , Espinas Dendríticas/ultraestructura , Homólogo 4 de la Proteína Discs Large/metabolismo , Proteínas de la Matriz Extracelular/genética , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Imagenología Tridimensional , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Microscopía Confocal , Mutación/genética , Proteínas del Tejido Nervioso/deficiencia , Proteínas del Tejido Nervioso/genética , Proteína Reelina , Serina Endopeptidasas/genética , Transducción de Señal/fisiología , Sinapsis/ultraestructura , Transducción GenéticaRESUMEN
Adult hippocampal neurogenesis is thought to be essential for learning and memory, and has been implicated in the pathogenesis of several disorders. Although recent studies have identified key factors regulating neuroprogenitor proliferation in the adult hippocampus, the mechanisms that control the migration and integration of adult-born neurons into circuits are largely unknown. Reelin is an extracellular matrix protein that is vital for neuronal development. Activation of the Reelin cascade leads to phosphorylation of Disabled-1, an adaptor protein required for Reelin signaling. Here we used transgenic mouse and retroviral reporters along with Reelin signaling gain-of-function and loss-of-function studies to show that the Reelin pathway regulates migration and dendritic development of adult-generated hippocampal neurons. Whereas overexpression of Reelin accelerated dendritic maturation, inactivation of the Reelin signaling pathway specifically in adult neuroprogenitor cells resulted in aberrant migration, decreased dendrite development, formation of ectopic dendrites in the hilus, and the establishment of aberrant circuits. Our findings support a cell-autonomous and critical role for the Reelin pathway in regulating dendritic development and the integration of adult-generated granule cells and point to this pathway as a key regulator of adult neurogenesis. Moreover, our data reveal a novel role of the Reelin cascade in adult brain function with potential implications for the pathogenesis of several neurological and psychiatric disorders.
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Moléculas de Adhesión Celular Neuronal/antagonistas & inhibidores , Proteínas de la Matriz Extracelular/antagonistas & inhibidores , Hipocampo/citología , Hipocampo/metabolismo , Proteínas del Tejido Nervioso/antagonistas & inhibidores , Neurogénesis/genética , Transducción de Señal/genética , Factores de Edad , Envejecimiento/genética , Animales , Moléculas de Adhesión Celular Neuronal/fisiología , Línea Celular , Células Cultivadas , Proteínas de la Matriz Extracelular/fisiología , Silenciador del Gen/fisiología , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Proteínas del Tejido Nervioso/fisiología , Ratas , Ratas Sprague-Dawley , Proteína Reelina , Serina Endopeptidasas/fisiologíaRESUMEN
Patients with Alzheimer's disease (AD) display altered functioning of cortical networks, including altered patterns of synchronous activity and a serious deficit in cholinergic septohippocampal (SH) innervation. However, the mechanisms underlying these alterations and the implication of the GABAergic SH component in AD are largely unknown. In addition, the GABAergic septohippocampal pathway (SHP) is believed to regulate synchronous hippocampal activity by controlling the activity of interneurons. Here we show, using well-characterized pathway tracing experiments, that innervation of the GABAergic SHP decreases during normal aging. Furthermore, in an AD mouse model (hAPP(Sw,Ind); J20 mice), the GABAergic SHP shows a dramatic and early onset of this decrease in 8-mo-old mice. This decline is not caused by neuronal loss, but by the reduced number and complexity of GABAergic SH axon terminals. Finally, we demonstrate that hippocampal θ and γ rhythm power spectra are markedly diminished in 8-mo-old behaving mice expressing mutated hAPP. In addition to the well-known loss of cholinergic input to the hippocampus in AD, these data suggest that the altered patterns of synchronous activity seen in patients with AD could be caused by the loss of GABAergic SH axons, which modulate hippocampal network activities.
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Envejecimiento , Enfermedad de Alzheimer/metabolismo , Neuronas GABAérgicas/fisiología , Hipocampo/fisiología , Enfermedad de Alzheimer/fisiopatología , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Animales , Modelos Animales de Enfermedad , Hipocampo/fisiopatología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Mutantes Neurológicos , Ratones Transgénicos , Núcleos Septales/citología , Ritmo Teta/fisiologíaRESUMEN
Correlative multimodal imaging is a useful approach to investigate complex structural relations in life sciences across multiple scales. For these experiments, sample preparation workflows that are compatible with multiple imaging techniques must be established. In one such implementation, a fluorescently labeled region of interest in a biological soft tissue sample can be imaged with light microscopy before staining the specimen with heavy metals, enabling follow-up higher resolution structural imaging at the targeted location, bringing context where it is required. Alternatively, or in addition to fluorescence imaging, other microscopy methods, such as synchrotron x-ray computed tomography with propagation-based phase contrast or serial blockface scanning electron microscopy, might also be applied. When combining imaging techniques across scales, it is common that a volumetric region of interest (ROI) needs to be carved from the total sample volume before high resolution imaging with a subsequent technique can be performed. In these situations, the overall success of the correlative workflow depends on the precise targeting of the ROI and the trimming of the sample down to a suitable dimension and geometry for downstream imaging. Here, we showcase the utility of a femtosecond laser (fs laser) device to prepare microscopic samples (1) of an optimized geometry for synchrotron x-ray tomography as well as (2) for volume electron microscopy applications and compatible with correlative multimodal imaging workflows that link both imaging modalities.
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Integrating physiology with structural insights of the same neuronal circuit provides a unique approach to understanding how the mammalian brain computes information. However, combining the techniques that provide both streams of data represents an experimental challenge. When studying glomerular column circuits in the mouse olfactory bulb, this approach involves e.g., recording the neuronal activity with in vivo 2-photon (2P) calcium imaging, retrieving the circuit structure with synchrotron X-ray computed tomography with propagation-based phase contrast (SXRT) and/or serial block-face scanning electron microscopy (SBEM) and correlating these datasets. Sample preparation and dataset correlation are two key bottlenecks in this correlative workflow. Here, we first quantify the occurrence of different artefacts when staining tissue slices with heavy metals to generate X-ray or electron contrast. We report improvements in the staining procedure, ultimately achieving perfect staining in â¼67% of the 0.6 mm thick olfactory bulb slices that were previously imaged in vivo with 2P. Secondly, we characterise the accuracy of the spatial correlation between functional and structural datasets. We demonstrate that direct, single-cell precise correlation between in vivo 2P and SXRT tissue volumes is possible and as reliable as correlating between 2P and SBEM. Altogether, these results pave the way for experiments that require retrieving physiology, circuit structure and synaptic signatures in targeted regions. These correlative function-structure studies will bring a more complete understanding of mammalian olfactory processing across spatial scales and time.
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Understanding the function of biological tissues requires a coordinated study of physiology and structure, exploring volumes that contain complete functional units at a detail that resolves the relevant features. Here, we introduce an approach to address this challenge: Mouse brain tissue sections containing a region where function was recorded using in vivo 2-photon calcium imaging were stained, dehydrated, resin-embedded and imaged with synchrotron X-ray computed tomography with propagation-based phase contrast (SXRT). SXRT provided context at subcellular detail, and could be followed by targeted acquisition of multiple volumes using serial block-face electron microscopy (SBEM). In the olfactory bulb, combining SXRT and SBEM enabled disambiguation of in vivo-assigned regions of interest. In the hippocampus, we found that superficial pyramidal neurons in CA1a displayed a larger density of spine apparati than deeper ones. Altogether, this approach can enable a functional and structural investigation of subcellular features in the context of cells and tissues.
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Imagenología Tridimensional , Sincrotrones , Animales , Encéfalo/diagnóstico por imagen , Encéfalo/ultraestructura , Imagen de Difusión por Resonancia Magnética , Ratones , Microscopía Electrónica , Microscopía Electrónica de Rastreo , Microtomografía por Rayos X/métodosRESUMEN
Reelin, an extracellular protein essential for neural migration and lamination, is also expressed in the adult brain. To unravel the function of this protein in the adult forebrain, we generated transgenic mice that overexpress Reelin under the control of the CaMKIIalpha promoter. Overexpression of Reelin increased adult neurogenesis and impaired the migration and positioning of adult-generated neurons. In the hippocampus, the overexpression of Reelin resulted in an increase in synaptic contacts and hypertrophy of dendritic spines. Induction of long-term potentiation (LTP) in alert-behaving mice showed that Reelin overexpression evokes a dramatic increase in LTP responses. Hippocampal field EPSP during a classical conditioning paradigm was also increased in these mice. Our results indicate that Reelin levels in the adult brain regulate neurogenesis and migration, as well as the structural and functional properties of synapses. These observations suggest that Reelin controls developmental processes that remain active in the adult brain.
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Moléculas de Adhesión Celular Neuronal/fisiología , Espinas Dendríticas/ultraestructura , Proteínas de la Matriz Extracelular/fisiología , Potenciación a Largo Plazo , Proteínas del Tejido Nervioso/fisiología , Prosencéfalo/metabolismo , Serina Endopeptidasas/fisiología , Animales , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/genética , Moléculas de Adhesión Celular Neuronal/genética , Movimiento Celular , Condicionamiento Clásico , Proteínas de la Matriz Extracelular/genética , Hipocampo/crecimiento & desarrollo , Hipocampo/metabolismo , Hipocampo/ultraestructura , Ratones , Ratones Transgénicos , Proteínas del Tejido Nervioso/genética , Neurogénesis , Neuronas/fisiología , Neuronas/ultraestructura , Regiones Promotoras Genéticas , Prosencéfalo/crecimiento & desarrollo , Prosencéfalo/ultraestructura , Proteína Reelina , Serina Endopeptidasas/genética , Sinapsis/fisiología , Sinapsis/ultraestructuraRESUMEN
OBJECTIVE: Due to their exceptional temperature sensitivity, the mechanical properties of Nickel-titanium and Copper Nickel-titanium wires may be influenced by their storage temperature. This in turn may have clinical implications and may also affect the outcomes. This study analyzed the influence of storage temperatures on the mechanical properties of orthodontic wires in a laboratory setting. MATERIALS AND METHODS: Stainless steel (SS), Nickel-Titanium (NiTi), and three variants of Copper-NiTi (Cu-NiTi 27°C, 35°C and 40°C), 0.017×0.025 inches in size were analysed using a three-point bending test in a pre-heated chamber at 36°C. The orthodontic wires were stored for twenty-four hours before the mechanical testing at four different temperatures (5°, 22°, 36° and 60°C). RESULTS: The obtained results showed that the mechanical forces exerted by 27°C Copper-NiTi exhibit the most stable behaviour after having been stored at different temperatures, whereas 35°C Copper-NiTi showed the highest variability. As to be expected, Stainless steel shows no changes in its bending mechanical properties. CONCLUSION: Furthermore, the results of this investigation reflect the importance of controlling the storage temperature of orthodontic NiTi and Copper-NiTi wires tested in a research environment in order to avoid unexpected bias.
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Cobre/química , Níquel/química , Aparatos Ortodóncicos , Alambres para Ortodoncia , Acero Inoxidable/química , Temperatura , Titanio/química , Aleaciones Dentales , Calor , Humanos , Ensayo de Materiales , Fenómenos Mecánicos , Estrés MecánicoRESUMEN
Currently, molecular, electrophysiological and structural studies delineate several neural subtypes in the hippocampus. However, the precise developmental mechanisms that lead to this diversity are still unknown. Here we show that alterations in a concrete hippocampal neuronal subpopulation during development specifically affect hippocampal-dependent spatial memory. We observed that the genetic deletion of the transcription factor Helios in mice, which is specifically expressed in developing hippocampal calbindin-positive CA1 pyramidal neurons (CB-CA1-PNs), induces adult alterations affecting spatial memory. In the same mice, CA3-CA1 synaptic plasticity and spine density and morphology in adult CB-CA1-PNs were severely compromised. RNAseq experiments in developing hippocampus identified an aberrant increase on the Visinin-like protein 1 (VSNL1) expression in the hippocampi devoid of Helios. This aberrant increase on VSNL1 levels was localized in the CB-CA1-PNs. Normalization of VSNL1 levels in CB-CA1-PNs devoid of Helios rescued their spine loss in vitro. Our study identifies a novel and specific developmental molecular pathway involved in the maturation and function of a CA1 pyramidal neuronal subtype.
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Proteínas de Unión al ADN/metabolismo , Neurocalcina/metabolismo , Neurogénesis/fisiología , Células Piramidales/fisiología , Memoria Espacial/fisiología , Factores de Transcripción/metabolismo , Animales , Región CA1 Hipocampal/crecimiento & desarrollo , Región CA1 Hipocampal/fisiología , Espinas Dendríticas/metabolismo , Femenino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Plasticidad Neuronal/fisiología , Células Piramidales/citologíaRESUMEN
Weathering effects are ubiquitous phenomena in cities. Buildings age and deteriorate over time as they interact with the environment. Pollution accumulating on facades is a particularly visible consequence of this. Even though relevant work has been done to produce impressive images of virtual urban environments including weathering effects, so far, no technique using a global approach has been proposed to deal with weathering effects. Here, we propose a technique based on a fast physically-inspired approach, that focuses on modeling the changes in appearance due to pollution soiling on an urban scale. We consider pollution effects to depend on three main factors: wind, rain and sun exposure, and we take into account three intervening steps: deposition, reaction and washing. Using a low-cost pre-computation, we evaluate the pollution distribution throughout the city. Based on this and the use of screen-space operators, our method results in an efficient approach able to generate realistic images of urban scenes by combining the intervening factors at interactive rates. In addition, the pre-computation demands a reduced amount of memory to store the resulting pollution map and, as it is independent from scene complexity, it can suit large and complex models by adapting the map resolution.
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BACKGROUND: Non-nutritive sucking habits may adversely affect the orofacial complex. This systematic literature review aimed to find scientific evidence on the effect of pacifier sucking on orofacial structures. METHODS: A search on MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Web of Science databases was conducted to find all pertinent articles published from inception until February 2018, based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The quality of the studies was evaluated using the risk of bias judgements in non-randomized studies of interventions (ROBINS-I). RESULTS: Among the 2288 articles found, 17 articles met the selection criteria: seven prospective cohort studies, nine cross-sectional studies, and one randomized clinical trial. Using ROBINS-I, 12 studies were evaluated to have a serious overall risk of bias and five, a moderate one. These studies claimed a strong association between a pacifier sucking habit and the presence of an anterior open bite and posterior crossbite. Functional/orthodontic pacifiers were shown to cause significantly less open bites than the conventional ones. CONCLUSIONS: High level of evidence of the effect of sucking habits on orofacial structures is missing. The available studies show severe or moderate risk of bias; hence, the findings in the literature need to be very carefully evaluated. There is moderate evidence that the use of pacifier is associated with anterior open bite and posterior crossbite, thus affecting the harmonious development of orofacial structures. Functional/orthodontic pacifiers reduce the prevalence of open bite when compared to the conventional ones, but evidence is needed concerning the effects on posterior crossbite. Well-designed randomized controlled trials are needed to further analyze the effects of functional/orthodontic and conventional pacifiers on orofacial structures.
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Maloclusión/etiología , Desarrollo Maxilofacial , Mordida Abierta/etiología , Chupetes/efectos adversos , Conducta en la Lactancia , Humanos , Lactante , Recién NacidoRESUMEN
PURPOSE: To compare the mechanical strength of surgically created and healed rat calvarial defects having been filled with three different osteopromotive substances: hydroxyapatite, intramembraneous demineralised bone matrix (DBM), and autogenous bone chips. MATERIAL: Sixty adult male Wistar rats were divided into three groups of 20 animals, each group representing healing times of one, three, or six months. METHODS: Identical 5mm bilateral critical size defects were trephined into the parietal bones and hydroxyapatite, DBM, or autogenous bone chips were implanted into the defects, or left as unfilled controls. The repaired defects were evaluated biomechanically using a modified punch out test 1, 3, or 6 months postoperatively. RESULTS: The maximum load carried in the DBM group was significantly higher than in the bone chips, hydroxyapatite, and control groups after one month of healing. The mean bone strength did not increase significantly after the first month of healing in any of the groups. The DBM group showed a significantly higher load to failure than the other groups at all three observation periods. The mean maximum load to failure of the bone chips and hydroxyapatite groups was slightly higher than in the control group; however the difference was not statistically significant. None of the control experimental bone defects demonstrated any bone formation. CONCLUSION: Defects filled with hydroxyapatite and bone chips were not significantly stronger than unfilled controls, whereas defects filled with DBM were significantly stronger than all other defects after 1, 3, and 6 months of healing.
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Materiales Biocompatibles/uso terapéutico , Enfermedades Óseas/cirugía , Trasplante Óseo/métodos , Cráneo/cirugía , Animales , Fenómenos Biomecánicos , Enfermedades Óseas/patología , Matriz Ósea/patología , Matriz Ósea/trasplante , Durapatita/uso terapéutico , Masculino , Osteogénesis/fisiología , Ratas , Ratas Wistar , Cráneo/patología , Fracturas Craneales/fisiopatología , Estrés Mecánico , Factores de Tiempo , Soporte de Peso/fisiología , Cicatrización de Heridas/fisiologíaRESUMEN
Reelin regulates neuronal positioning and synaptogenesis in the developing brain, and adult brain plasticity. Here we used transgenic mice overexpressing Reelin (Reelin-OE mice) to perform a comprehensive dissection of the effects of this protein on the structural and biochemical features of dendritic spines and axon terminals in the adult hippocampus. Electron microscopy (EM) revealed both higher density of synapses and structural complexity of both pre- and postsynaptic elements in transgenic mice than in WT mice. Dendritic spines had larger spine apparatuses, which correlated with a redistribution of Synaptopodin. Most of the changes observed in Reelin-OE mice were reversible after blockade of transgene expression, thus supporting the specificity of the observed phenotypes. Western blot and transcriptional analyses did not show major changes in the expression of pre- or postsynaptic proteins, including SNARE proteins, glutamate receptors, and scaffolding and signaling proteins. However, EM immunogold assays revealed that the NMDA receptor subunits NR2a and NR2b, and p-Cofilin showed a redistribution from synaptic to extrasynaptic pools. Taken together with previous studies, the present results suggest that Reelin regulates the structural and biochemical properties of adult hippocampal synapses by increasing their density and morphological complexity and by modifying the distribution and trafficking of major glutamatergic components.
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[This corrects the article on p. 60 in vol. 9, PMID: 26052271.].
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PURPOSE: To assess tolerance and efficacy of preoperative treatment with uracil/tegafur and radiotherapy (RT) followed by surgery and postoperative flurouracil (FU)/leucovorin (LV) in patients with rectal cancer. PATIENTS AND METHODS: Patients (n = 94) with potentially resectable tumors, ultrasound at stages T2N+ (n = 4), T3 (n = 77), T4 (n = 13) were treated with UFT (400 mg/m2/d, 5 days a week for 5 weeks) and concomitant RT to the pelvis (45 Gy; 1.8 Gy/d over 5 weeks). Patients underwent surgery 5 to 6 weeks later followed by four cycles of FU/LV. Primary end points included downstaging, pathologic responses, and sphincter-preserving surgery. Secondary end points were recurrence-free survival and overall survival. RESULTS: All patients received the full RT dose. Fifteen patients (16%) needed UFT dose reduction. Preoperative G3+ toxicities included diarrhea (14%), leukopenia (1%), thrombocytopenia (1%), and nausea (4%). The downstaging rate was 54%, pathologic complete response (pCR) was 9% and, in an additional 23%, there were only residual microscopic foci. When cellular viability criteria were taken into account, the pCR was 15%. From 43 patients with abdominoperineal resection indication, 11 (25%) had sphincter-preserving surgery performed. Postoperative scheduled chemotherapy dose was not administered to 24% of patients because of G3+ toxicity (diarrhea, 8%; mucositis, 9%; and leukopenia, 7%). Patients with downstaging had significantly higher survival and recurrence-free survival rates than those without. At 3 years, actuarial patterns of failure were pelvic, 5% and distant, 11%. OS was 75%. CONCLUSION: UFT combined with RT is safe and effective. In resectable rectal cancer, if preoperative treatment is considered, this approach can be an option.
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Adenocarcinoma/terapia , Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Neoplasias del Recto/terapia , Tegafur/administración & dosificación , Uracilo/administración & dosificación , Adenocarcinoma/mortalidad , Adulto , Anciano , Anciano de 80 o más Años , Terapia Combinada , Supervivencia sin Enfermedad , Femenino , Estudios de Seguimiento , Humanos , Leucovorina/administración & dosificación , Masculino , Persona de Mediana Edad , Periodo Posoperatorio , Cuidados Preoperatorios , Neoplasias del Recto/mortalidad , Neoplasias del Recto/radioterapia , Neoplasias del Recto/cirugíaRESUMEN
The fine analysis of synaptic contacts is usually performed using transmission electron microscopy (TEM) and its combination with neuronal labeling techniques. However, the complex 3D architecture of neuronal samples calls for their reconstruction from serial sections. Here we show that focused ion beam/scanning electron microscopy (FIB/SEM) allows efficient, complete, and automatic 3D reconstruction of identified dendrites, including their spines and synapses, from GFP/DAB-labeled neurons, with a resolution comparable to that of TEM. We applied this technology to analyze the synaptogenesis of labeled adult-generated granule cells (GCs) in mice. 3D reconstruction of dendritic spines in GCs aged 3-4 and 8-9 weeks revealed two different stages of dendritic spine development and unexpected features of synapse formation, including vacant and branched dendritic spines and presynaptic terminals establishing synapses with up to 10 dendritic spines. Given the reliability, efficiency, and high resolution of FIB/SEM technology and the wide use of DAB in conventional EM, we consider FIB/SEM fundamental for the detailed characterization of identified synaptic contacts in neurons in a high-throughput manner.
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Psychiatric disorders have been hypothesized to originate during development, with genetic and environmental factors interacting in the etiology of disease. Therefore, developmentally regulated genes have received attention as risk modulators in psychiatric diseases. Reelin is an extracellular protein essential for neuronal migration and maturation during development, and its expression levels are reduced in psychiatric disorders. Interestingly, several perinatal insults that increase the risk of behavioral deficits alter Reelin signaling. However, it is not known whether a dysfunction in Reelin signaling during perinatal stages increases the risk of psychiatric disorders. Here we used a floxed dab1 allele to study whether a transient decrease in Dab1, a key component of the Reelin pathway, is sufficient to induce behavioral deficits related to psychiatric disorders. We found that transient Dab1 downregulation during perinatal stages leads to permanent abnormalities of structural layering in the neocortex and hippocampus. In contrast, conditional inactivation of the dab1 gene in the adult brain does not result in additional layering abnormalities. Furthermore, perinatal Dab1 downregulation causes behavior impairments in adult mice, such as deficits in memory, maternal care, pre-pulse inhibition, and response to cocaine. Some of these deficits were also found to be present in adolescence. We also show that D-cycloserine rescues the cognitive deficits observed in floxed dab1 mice with layering alterations in the hippocampus and neocortex. Our results indicate a causal relation between the downregulation of Dab1 protein levels during development and the structural and behavioral deficits associated with psychiatric diseases in the adult.