435 research outputs found
Effects of Amphetamine on Striatal Dopamine Release, Open-Field Activity, and Play in Fischer 344 and SpragueâDawley Rats
Previous work from our laboratories has shown that juvenile Fischer 344 (F344) rats are less playful than other strains and also appear to be compromised in dopamine (DA) functioning. To determine whether the dysfunctional play in this strain is associated with deficits in the handling and delivery of vesicular DA, the following experiments assessed the extent to which F344 rats are differentially sensitive to the effects of amphetamine. When exposed to amphetamine, striatal slices obtained from F344 rats showed a small increase in unstimulated DA release when compared with slices from SpragueâDawley rats; they also showed a more rapid high K+-mediated release of DA. These data provide tentative support for the hypothesis that F344 rats have a higher concentration of cytoplasmic DA than SpragueâDawley rats. When rats were tested for activity in an open field, F344 rats presented a pattern of results that was consistent with either an enhanced response to amphetamine (3âmg/kg) or a more rapid release of DA (10âmg/kg). Although there was some indication that amphetamine had a dose-dependent differential effect on play in the two strains, play in F344 rats was not enhanced to any degree by amphetamine. Although these results are not consistent with our working hypothesis that F344 rats are less playful because of a deficit in vesicular release of DA, they still suggest that this strain may be a useful model for better understanding the role of DA in social behavior during the juvenile period
Acute Dacryocystitis with Empyema of the Lacrimal Sac: Is Immediate Endoscopic Dacryocystorhinostomy Justified?
Objectives. To evaluate the efficacy of endoscopic dacryocystorhinostomy (Endo-DCR) in the treatment of acute dacryocystitis with lacrimal sac empyema (ADLSE). Design. Case series with chart review. Setting. Academic tertiary center. Patients. The study included 26 consecutive patients who underwent Endo-DCR for ADLSE between August 2005 and December 2013. Main Outcome Measures. The success of the procedure was defined as complete complaint relief and DCR patency. Data on the time from referral to surgery, postoperative complications, and revision surgery are also reported. Results. The present patient series included 4 males (15.4%) and 22 females (84.6%) (mean age, 66 years). The mean time between referral and surgery was 0.88 days and the mean follow-up time was 29 months. All patients showed immediate relief from symptoms, with no ADLSE recurrences. Complete success was achieved in 25 (96.2%) cases; the only failure was in a patient who had previously undergone radioiodine treatment. In this case, revision Endo-DCR was not successful. The only perioperative complication (3.8%) was epistaxis in a patient who required revision surgery under general anesthesia. The definitive success rate was 96.2% after primary and revision surgery. Conclusions. Endo-DCR enables rapid resolution of ADLSE with a very high success rate. Immediate surgery may reduce the risk of skin fistulization and/or orbital complications. DCR shrinkage and lacrimal obstruction are unlikely with Endo-DCR since the procedure is performed on an enlarged sac. The main advantage of Endo-DCR, compared with external DCR, is the absence of a skin incision in an inflamed and infected field
AmineâFunctionalized Mesoporous Silica Adsorbent for CO2 Capture in ConfinedâFluidized Bed: Study of the Breakthrough Adsorption Curves as a Function of Several Operating Variables
Carbon capture, utilization, and storage (CCUS) is one of the key promising technologies that can reduce GHG emissions from those industries that generate CO2 as part of their production processes. Compared to other effective CO2 capture methods, the adsorption technique offers the possibility of reducing the costs of the process by setting solid sorbent with a high capacity of adsorption and easy regeneration and, also, controlling the performance of gasâsolid contactor. In this work, an amineâfunctionalized mesoporous sorbent was used to capture CO2 emissions in a confinedâfluidized bed. The adoption of a confined environment allows the establishment of a homogeneous expansion regime for the sorbent and allows to improve the exchange of matter and heat between gas and solid phase. The results illustrate how the different concentration of the solution adopted during the functionalization affects the adsorption capacity. That, measured as mg of CO2 per g of sorbent, was determined by breakthrough curves from continuous adsorption tests using different concentrations of CO2 in air. Mesoporous silica functionalized with a concentration of 20% of APTES proves to be the best viable option in terms of cost and ease of preparation, low temperature of regeneration, and effective use for CO2 capture
A dynamic link between H/ACA snoRNP components and cytoplasmic stress granules
Many cell stressors block protein translation, inducing formation of cytoplasmic aggregates. These aggregates, named stress granules (SGs), are composed by translationally stalled ribonucleoproteins and their assembly strongly contributes to cell survival. Composition and dynamics of SGs are thus important starting points for identifying critical factors of the stress response. In the present study we link components of the H/ACA snoRNP complexes, highly concentrated in the nucleoli and the Cajal bodies, to SG composition. H/ACA snoRNPs are composed by a core of four highly conserved proteins -dyskerin, Nhp2, Nop10 and Gar1- and are involved in several fundamental processes, including ribosome biogenesis, RNA pseudouridylation, stabilization of small nucleolar RNAs and telomere maintenance. By taking advantage of cells overexpressing a dyskerin splice variant undergoing a dynamic intracellular trafficking, we were able to show that H/ACA snoRNP components can participate in SG formation, this way contributing to the stress response and perhaps transducing signals from the nucleus to the cytoplasm. Collectively, our results show for the first time that H/ACA snoRNP proteins can have additional non-nuclear functions, either independently or interacting with each other, thus further strengthening the close relationship linking nucleolus to SG composition
The anti-apoptotic effect of ASC-exosomes in an in vitro ALS model and their proteomic analysis
Stem cell therapy represents a promising approach in the treatment of several neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS). The beneficial effect of stem cells is exerted by paracrine mediators, as exosomes, suggesting a possible potential use of these extracellular vesicles as non-cell based therapy. We demonstrated that exosomes isolated from adipose stem cells (ASC) display a neuroprotective role in an in vitro model of ALS. Moreover, the internalization of ASC-exosomes by the cells was shown and the molecules and the mechanisms by which exosomes could exert their beneficial effect were addressed. We performed for the first time a comprehensive proteomic analysis of exosomes derived from murine ASC. We identified a total of 189 proteins and the shotgun proteomics analysis revealed that the exosomal proteins are mainly involved in cell adhesion and negative regulation of the apoptotic process. We correlated the protein content to the anti-apoptotic effect of exosomes observing a downregulation of pro-apoptotic proteins Bax and cleaved caspase-3 and upregulation of anti-apoptotic protein Bcl-2 \u3b1, in an in vitro model of ALS after cell treatment with exosomes. Overall, this study shows the neuroprotective effect of ASC-exosomes after their internalization and their global protein profile, that could be useful to understand how exosomes act, demonstrating that they can be employed as therapy in neurodegenerative diseases
Diauxie and co-utilization of carbon sources can coexist during bacterial growth in nutritionally complex environments
It is commonly thought that when multiple carbon sources are available, bacteria metabolize them either sequentially (diauxic growth) or simultaneously (co-utilization). However, this view is mainly based on analyses in relatively simple laboratory settings. Here we show that a heterotrophic marine bacterium, Pseudoalteromonas haloplanktis, can use both strategies simultaneously when multiple possible nutrients are provided in the same growth experiment. The order of nutrient uptake is partially determined by the biomass yield that can be achieved when the same compounds are provided as single carbon sources. Using transcriptomics and time-resolved intracellular 1H-13C NMR, we reveal specific pathways for utilization of various amino acids. Finally, theoretical modelling indicates that this metabolic phenotype, combining diauxie and co-utilization of substrates, is compatible with a tight regulation that allows the modulation of assimilatory pathways
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