6,878 research outputs found

    Chemokine fractalkine/CX3CL1 negatively modulates active glutamatergic synapses in rat hippocampal neurons

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    We examined the effects of the chemokine fractalkine (CX3CL1) on EPSCs evoked by electrical stimulation of Schaffer collaterals in patch-clamped CA1 pyramidal neurons from rat hippocampal slices. Acute application of CX3CL1 caused a sustained reduction of EPSC amplitude, with partial recovery after washout. CX3CL1-induced EPSC depression is postsynaptic in nature, because paired-pulse ratio was maintained, amplitude distribution of spontaneous excitatory postsynaptic currents shifted to lower values, and whole-cell current responses to AMPA were reversibly inhibited. EPSC depression by CX3CL1 is mediated by CX3CL1 receptor (CX3CR1), because CX3CL1 was unable to influence EPSC amplitude in CA1 pyramidal neurons from CX3CR1 knock-out mice. CX3CL1-induced depression of both EPSC and AMPA current was not observed in the absence of afferent fiber stimulation or AMPA receptor activation, respectively, indicating the requirement of sustained receptor activity for its development. Findings obtained from hippocampal slices, cultured hippocampal neurons, and transfected human embryonic kidney cells indicate that a Ca2+-, cAMP-, and phosphatase-dependent process is likely to modulate CX3CL1 effects because of the following: (1) CX3CL1-induced depression was antagonized by intracellular BAPTA, 8Br-cAMP, phosphatase inhibitors, and pertussis toxin (PTX); (2) CX3CL1 inhibited forskolin-induced cAMP formation sensitive to PTX; and (3) CX3CL1 inhibited forskolin-induced Ser845 GluR1 phosphorylation, which was sensitive to PTX and dependent on Ca2+ and phosphatase activity. Together, these findings indicate that CX3CL1 negatively modulates AMPA receptor function at active glutamatergic synapses through cell-signaling pathways by influencing the balance between kinase and phosphatase activity

    Cerebrospinal fluid Aβ42/40 corresponds better than Aβ42 to amyloid PET in Alzheimer’s disease

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    Background: Decreased concentrations of amyloid-β 1-42 (Aβ(42)) in cerebrospinal fluid (CSF) and increased retention of Aβ tracers in the brain on positron emission tomography (PET) are considered the earliest biomarkers of Alzheimer’s disease (AD). However, a proportion of cases show discrepancies between the results of the two biomarker modalities which may reflect inter-individual differences in Aβ metabolism. The CSF Aβ(42/40) ratio seems to be a more accurate biomarker of clinical AD than CSF Aβ(42) alone. Objective: We tested whether CSF Aβ(42) alone or the Aβ(42/40) ratio corresponds better with amyloid PET status and analyzed the distribution of cases with discordant CSF-PET results. Methods: CSF obtained from a mixed cohort (n = 200) of cognitively normal and abnormal research participants who had undergone amyloid PET within 12 months (n = 150 PET-negative, n = 50 PET-positive according to a previously published cut-off) was assayed for Aβ(42) and Aβ(40) using two recently developed immunoassays. Optimal CSF cut-offs for amyloid positivity were calculated, and concordance was tested by comparison of the areas under receiver operating characteristic (ROC) curves (AUC) and McNemar’s test for paired proportions. Results: CSF Aβ(42/40) corresponded better than Aβ(42) with PET results, with a larger proportion of concordant cases (89.4% versus 74.9%, respectively, p < 0.0001) and a larger AUC (0.936 versus 0.814, respectively, p < 0.0001) associated with the ratio. For both CSF biomarkers, the percentage of CSF-abnormal/PET-normal cases was larger than that of CSF-normal/PET-abnormal cases. Conclusion: The CSF Aβ(42/40) ratio is superior to Aβ(42) alone as a marker of amyloid-positivity by PET. We hypothesize that this increase in performance reflects the ratio compensating for general between-individual variations in CSF total Aβ

    Endoscopic ultrasound-guided fine-needle aspiration vs fine-needle biopsy for the diagnosis of pancreatic neuroendocrine tumors

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    Background and study aims Endoscopic ultrasoundguided fine-needle aspiration (EUS-FNA) as a method of obtaining preoperative diagnosis of pancreatic neuroendocrine tumors (PanNETs) has been reported in several series. Fine-needle biopsies (FNB) are increasingly employed to obtain core specimens during EUS. However, the differences in efficacy between these sampling methods in the diagnosis of PanNETs still needs to be defined. Patients and methods Over a 13-year period, all patients who underwent EUS-guided tissue sampling of suspicious pancreatic lesions with clinical, endoscopic and pathologic details were entered into an electronic database. Lesions underwent EUS-FNA or FNB sampling, or a combination of the two. The accuracy and safety of different EUS-guided sampling methods for confirmed PanNETs were investigated. Results A total of 91 patients (M/F: 42/49, median age: 57 years), who underwent 102 EUS procedures had a final diagnosis of PanNET. Both EUS-guided sampling modalities were used in 28 procedures, EUS-FNA alone was used in 61 cases, while EUS-FNB alone in 13 cases. Diagnostic yield of EUS-FNA and EUS-FNB alone, including the inadequate specimens, was 77.5 % (95 %CI: 68.9 – 86.2%) and 85.4 % (95 % CI: 74.6 – 96.2 %), respectively. The combination of both sampling modalities established the diagnosis in 96.4 % of cases (27/28) (95 %CI: 89.6 – 100%), significantly superior to EUS-FNA alone (P = 0.023). Diagnostic sensitivity among the adequate samples for EUS-FNA, EUS-FNB and for the combination of the two methods was 88.4 % (95 %CI: 80.9 – 96.0 %), 94.3% (95 %CI: 86.6 – 100%) and 100% (95% CI: 100 – 100 %). There was one reported complication, a post-FNA bleeding, treated conservatively. Conclusions EUS-FNB improves diagnostic sensitivity and confers additional information to cytological assessment of PanNETs

    El taller de arqueología definido por sus integrantes

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    El taller de Arqueología del Museo "Alte Brown", de Bernal, fué creado en abril de 1987 y depende de la Municipalidad de Quilmes. A principios de 1988 ingresa un nuevo grupo, estableciéndose dos niveles los que se fusionarán en único nivel, para 1989. Objetivos del taller: Una permanente consideración de las metas y objetivos personales de cada miembro del grupo del Taller, ha permitido resumir estos objetivos en dos grupos; a) Objetivos iniciales: De las encuestas realizadas al iniciarse las reuniones surgieron las siguientes inquietudes: - Asistir a clases y conferencias sobre historia y arqueología. - Efectuar o colaborar en tareas afines o propias del arqueólogo. - Búsqueda de información histórica (sobre Egipto particularmente). - Conocer sobre métodos de análisis e interpretación. b) Objetivos actuales: Hoy los objetivos pueden resumirse en: - Adquirir nociones sobre métodos y técnicas en Arqueología. - Ampliar nuestro panorama de la Arqueología Argentina. - Concientizar (nos) de la importancia del Rescate y Protección del patrimonio arqueológico.Facultad de Ciencias Naturales y Muse

    Calcitonin free oat-cell carcinoma of the thyroid gland

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    Two cases of primary oat-cell carcinoma of thyroid, in a 63-year-old woman and a 73-year-old man, are described. Case 1 was a compound tumour with the oat-cell component merging with a papillary component. Both tumours, in addition to histological features consistent with oat-cell carcinoma, showed immunohistochemical positivity with anti-chromagranin A and anti-synaptophysin antisera. Negative results were obtained when anti-calcitonin and anti-thyroglobulin antisera were employed. Using in situ hybridization, chromogranin A and B messenger RNAs were localized with biotinylated oligonucleotide probes. In contrast, with in situ hybridization, no localization for calcitonin messenger RNA was seen using radioactive and biotinylated probes. It is concluded that these calcitonin-free, small-cell carcinomas should be considered separately from medullary thyroid carcinomas and be regarded as a distinct entity, probably the thyroid equivalent of oat-cell carcinomas of the lung.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47516/1/428_2005_Article_BF01600144.pd

    Operational experience, improvements, and performance of the CDF Run II silicon vertex detector

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    The Collider Detector at Fermilab (CDF) pursues a broad physics program at Fermilab's Tevatron collider. Between Run II commissioning in early 2001 and the end of operations in September 2011, the Tevatron delivered 12 fb-1 of integrated luminosity of p-pbar collisions at sqrt(s)=1.96 TeV. Many physics analyses undertaken by CDF require heavy flavor tagging with large charged particle tracking acceptance. To realize these goals, in 2001 CDF installed eight layers of silicon microstrip detectors around its interaction region. These detectors were designed for 2--5 years of operation, radiation doses up to 2 Mrad (0.02 Gy), and were expected to be replaced in 2004. The sensors were not replaced, and the Tevatron run was extended for several years beyond its design, exposing the sensors and electronics to much higher radiation doses than anticipated. In this paper we describe the operational challenges encountered over the past 10 years of running the CDF silicon detectors, the preventive measures undertaken, and the improvements made along the way to ensure their optimal performance for collecting high quality physics data. In addition, we describe the quantities and methods used to monitor radiation damage in the sensors for optimal performance and summarize the detector performance quantities important to CDF's physics program, including vertex resolution, heavy flavor tagging, and silicon vertex trigger performance.Comment: Preprint accepted for publication in Nuclear Instruments and Methods A (07/31/2013

    Extracellular vesicles and pancreatic cancer: Insights on the roles of mirna, lncrna, and protein cargos in cancer progression

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    Pancreatic cancer (PC) is among the most devastating digestive tract cancers worldwide. This cancer is characterized by poor diagnostic detection, lack of therapy, and difficulty in predicting tumorigenesis progression. Although mutations of key oncogenes and oncosuppressor involved in tumor growth and in immunosurveillance escape are known, the underlying mechanisms that orchestrate PC initiation and progression are poorly understood or still under debate. In recent years, the attention of many researchers has been concentrated on the role of extracellular vesicles and of a particular subset of extracellular vesicles, known as exosomes. Literature data report that these nanovesicles are able to deliver their cargos to recipient cells playing key roles in the pathogenesis and progression of many pancreatic precancerous conditions. In this review, we have summarized and discussed principal cargos of extracellular vesicles characterized in PC, such as miRNAs, lncRNAs, and several proteins, to offer a systematic overview of their function in PC progression. The study of extracellular vesicles is allowing to understand that investigation of their secretion and analysis of their content might represent a new and potential diagnostic and prognostic tools for PC

    Hybrid membrane distillation reverse electrodialysis configuration for water and energy recovery from human urine: an opportunity for off-grid decentralised sanitation

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    The integration of membrane distillation with reverse electrodialysis has been investigated as a sustainable sanitation solution to provide clean water and electrical power from urine and waste heat. Reverse electrodialysis was integrated to provide the partial remixing of the concentrate (urine) and diluate (permeate) produced from the membrane distillation of urine. Broadly comparable power densities to those of a model salt solution (sodium chloride) were determined during evaluation of the individual and combined contribution of the various monovalent and multivalent inorganic and organic salt constituents in urine. Power densities were improved through raising feed-side temperature and increasing concentration in the concentrate, without observation of limiting behaviour imposed by non-ideal salt and water transport. A further unique contribution of this application is the limited volume of salt concentrate available, which demanded brine recycling to maximise energy recovery analogous to a battery, operating in a ‘state of charge’. During recycle, around 47% of the Gibbs free energy was recoverable with up to 80% of the energy extractable before the concentration difference between the two solutions was halfway towards equilibrium which implies that energy recovery can be optimised with limited effect on permeate quality. This study has provided the first successful demonstration of an integrated MD-RED system for energy recovery from a limited resource, and evidences that the recovered power is sufficient to operate a range of low current fluid pumping technologies that could help deliver off-grid sanitation and clean water recovery at single household scale
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