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1.
Environ Pollut ; 345: 123524, 2024 Mar 15.
Article in English | MEDLINE | ID: mdl-38355090

ABSTRACT

Plastic pollution is ubiquitous in aquatic environments worldwide. Rivers connect terrestrial and marine ecosystems, playing a key role in the transport of land-based plastic waste towards the sea. Emerging research suggests that in estuaries and tidal rivers, tidal dynamics play a significant role in plastic transport and retention dynamics. To date, observations in these systems have been limited, and plastic transport dynamics during single tidal cycles remain poorly understood. Here, we investigated plastic transport, trapping, and re-mobilization of macroplastics (> 0.5 cm) in the Saigon River, focusing on short-term dynamics of individual tidal cycles. We used GPS trackers, released at different stages of the tidal cycle (ebb, flood, neap, spring). Plastic items demonstrated dynamic and intermittent transport behavior. Items spent almost half of the time (49%) temporarily stopped, mainly due to their entrapment in vegetation, infrastructure, or deposition on riverbanks. Items were almost always re-mobilized within 10 h (85%), leading to successive phases of stopping and transport. Tidal dynamics also resulted in bidirectional transport of plastic items, with median daily total transport distance within the 40 km study reach (8.9 km day-1) over four times larger than the median daily net distance (2.0 km day-1). The median retention time of plastic items within the reach was 21 days (mean = 202 days). In total, 81% of the retrieved items were trapped within water hyacinths, emphasizing the important role of floating vegetation on river plastic transport dynamics. With this paper, we aim to provide data-driven insights into macroplastic transport and retention dynamics in a tropical tidal river. These are crucial in the design of effective intervention and monitoring strategies, and estimating net plastic emission from rivers into the sea.


Subject(s)
Ecosystem , Rivers , Rivers/chemistry , Plastics , Environmental Monitoring , Estuaries
2.
J Hosp Infect ; 127: 121-128, 2022 Sep.
Article in English | MEDLINE | ID: mdl-35714830

ABSTRACT

BACKGROUND: In 2016, the Vietnamese Ministry of Health promoted development of antimicrobial stewardship for hospitals. AIM: To evaluate the effectiveness and safety of the enhanced antibiotic stewardship programme (ASP) compared to the original ASP among paediatric patients at a tertiary hospital for infectious diseases in Vietnam. METHODS: An interrupted time-series analysis was conducted to examine antibiotic use in paediatric patients aged 0-17 years admitted to the Hospital for Tropical Diseases in Ho Chi Minh City from April 2016 to March 2020. Outcomes measured were defined daily doses (DDDs) per 1000 patient-days; antibiotic days of therapy (DOT) per 1000 patient-days; percentage of antibiotic use by the World Health Organization Access, Watch, and Reserve (AWaRe) system; Access-to-Watch ratio; and worse clinical outcomes at discharge. FINDINGS: Of 60,172 admissions during the study period, 28,019 received at least one antibiotic (46.6%) during hospital stay. The Watch antibiotics were the most frequently prescribed (78.1% of total antibiotic courses). The enhanced ASP did not improve antibiotic prescribing by DDDs per 1000 patient-days (risk ratio: 1.05; 95% confidence interval: 0.94-1.17) and DOT per 1000 patient-days (1.11; 0.99-1.25) compared to the original ASP. However, the percentage of Access antibiotics prescribed, and the Access-to-Watch ratio increased after the enhanced ASP (1.73; 1.38-2.17). There was no significant difference in worse clinical outcomes at discharge between the original and enhanced ASP (1.25; 0.78-2.00). CONCLUSION: The enhanced ASP had modest impact on antibiotic consumption in the paediatric population despite the improvement of Access antibiotic use and the Access-to-Watch ratio.


Subject(s)
Antimicrobial Stewardship , Cross Infection , Anti-Bacterial Agents/therapeutic use , Child , Cross Infection/drug therapy , Humans , Tertiary Care Centers , Vietnam
3.
Mar Pollut Bull ; 159: 111490, 2020 Oct.
Article in English | MEDLINE | ID: mdl-32738641

ABSTRACT

Laboratories from 14 countries (with different levels of expertise in radionuclide measurements and 210Pb dating) participated in an interlaboratory comparison exercise (ILC) related to the application of 210Pb sediment dating technique within the framework of the IAEA Coordinated Research Project. The laboratories were provided with samples from a composite sediment core and were required to provide massic activities of several radionuclides and an age versus depth model from the obtained results, using the most suitable 210Pb dating model. Massic concentrations of Zn and Cu were also determined to be used for chronology validation. The ILC results indicated good analytical performances while the dating results didn't demonstrate the same degree of competence in part due to the different experience in dating of the participant laboratories. The ILC exercise enabled evaluation of the difficulties faced by laboratories implementing 210Pb dating methods and identified some limitations in providing reliable chronologies.


Subject(s)
Lead Radioisotopes/analysis , Lead , Environmental Monitoring , Geologic Sediments , Humans , Radiometry
4.
J Hosp Infect ; 104(4): 582-591, 2020 Apr.
Article in English | MEDLINE | ID: mdl-31927037

ABSTRACT

BACKGROUND: Heterogeneity of outcomes measured in trials to improve antimicrobial stewardship (AMS) in care homes has compromised quality of evidence. A core outcome set (COS) is needed to facilitate interpretation and synthesis of evidence in this area. AIM: To determine outcomes deemed important by relevant stakeholders for interventions aimed at improving AMS in care homes, and to produce a refined list of outcomes that could be considered for use in future research. METHODS: Semi-structured face-to-face or telephone interviews were conducted with key stakeholders. Outcomes reported in previous randomized controlled trials (RCTs) of AMS in care homes were included in a topic guide for interviews. Content analysis was undertaken to identify potential outcomes suggested by participants, followed by further review. FINDINGS: Twenty-seven outcomes reported in RCTs were refined into a list of 12 overarching outcomes. Interviews with participants (six researchers, 31 healthcare professionals, and four family members of care home residents) identified 40 additional outcomes that were important to them. From these 52 outcomes, the total number of antimicrobials, the appropriateness of antimicrobial prescribing and adherence to guidelines were highlighted by most participants. After reviewing all 52 outcomes, a refined list of 14 outcomes potentially feasible for use in AMS trials in care homes was generated. CONCLUSION: s: A number of potential outcomes for AMS in care homes, some of which had not been reported in previous studies, were identified. The refined list of 14 outcomes will be used in a future study to agree a COS for care home AMS trials.


Subject(s)
Anti-Bacterial Agents/therapeutic use , Health Knowledge, Attitudes, Practice , Health Personnel/psychology , Adult , Aged , Antimicrobial Stewardship , Drug Resistance, Microbial , Female , Homes for the Aged , Humans , Interviews as Topic , Male , Middle Aged , Northern Ireland , Nursing Homes , Practice Guidelines as Topic
5.
Adv Opt Mater ; 5(3)2017 Feb 02.
Article in English | MEDLINE | ID: mdl-28936383

ABSTRACT

Encoded microparticles have become a powerful tool for a wide array of applications, including high-throughput sample tracking and massively parallel biological multiplexing. Spectral encoding, where particles are encoded with distinct luminescence spectra, provides a particularly appealing encoding strategy because of the ease of reading codes and assay flexibility. To date, spectral encoding has been limited in the number of codes that can be accurately resolved. Here, we demonstrate an automated 5-dimensional spectral encoding scheme using lanthanide nanophosphors that is capable of producing isotropic spherical microparticles with up to 1,100 unique codes, which we term MRBLEs (Microspheres with Ratiometric Barcode Lanthanide Encoding). We further develop a quantitative framework for evaluating global ability to distinguish codes and demonstrate that for six different sets of MRBLEs ranging from 106 to 1,101 codes in size, > 98% of MRBLEs can be assigned to a code with 99.99% confidence. These > 1,000 code sets represent the largest spectral code libraries built to date. We expect that these MRBLEs will enable a wide variety of novel multiplexed assays.

6.
Sci Rep ; 6: 38166, 2016 11 30.
Article in English | MEDLINE | ID: mdl-27901081

ABSTRACT

Typically the disorder that alters the interference of particle waves to produce Anderson localization is potential scattering from randomly placed impurities. Here we show that disorder in the form of random gauge fields that act directly on particle phases can also drive localization. We present evidence of a superfluid bose glass to insulator transition at a critical level of this gauge field disorder in a nano-patterned array of amorphous Bi islands. This transition shows signs of metallic transport near the critical point characterized by a resistance , indicative of a quantum phase transition. The critical disorder depends on interisland coupling in agreement with recent Quantum Monte Carlo simulations. We discuss how this disorder tuned SIT differs from the common frustration tuned SIT that also occurs in magnetic fields. Its discovery enables new high fidelity comparisons between theoretical and experimental studies of disorder effects on quantum critical systems.

7.
Sci Rep ; 5: 17398, 2015 Dec 01.
Article in English | MEDLINE | ID: mdl-26620423

ABSTRACT

The control of electronic and thermal transport through material interfaces is crucial for numerous micro and nanoelectronics applications and quantum devices. Here we report on the engineering of the electro-thermal properties of semiconductor-superconductor (Sm-S) electronic cooler junctions by a nanoscale insulating tunnel barrier introduced between the Sm and S electrodes. Unexpectedly, such an interface barrier does not increase the junction resistance but strongly reduces the detrimental sub-gap leakage current. These features are key to achieving high cooling power tunnel junction refrigerators, and we demonstrate unparalleled performance in silicon-based Sm-S electron cooler devices with orders of magnitudes improvement in the cooling power in comparison to previous works. By adapting the junctions in strain-engineered silicon coolers we also demonstrate efficient electron temperature reduction from 300 mK to below 100 mK. Investigations on junctions with different interface quality indicate that the previously unexplained sub-gap leakage current is strongly influenced by the Sm-S interface states. These states often dictate the junction electrical resistance through the well-known Fermi level pinning effect and, therefore, superconductivity could be generally used to probe and optimize metal-semiconductor contact behaviour.

8.
Dokl Biochem Biophys ; 464: 338-40, 2015.
Article in English | MEDLINE | ID: mdl-26518563

ABSTRACT

This work is devoted to the study and obtaining of new radioprotective agents based on natural flavonoid genistein and spherical amorphous nanoparticles (SANPs) produced from a mixture of birch bark triterpenoids. The physicochemical characteristics of the nanoparticles were studied by electron microscopy, dynamic light scattering, and UV-VIS spectroscopy. The radioprotective efficacy of the nanodrug in vivo and the possibility of its use as a radioprotective agent was shown.


Subject(s)
Betula , Genistein/pharmacology , Metal Nanoparticles , Phytotherapy , Plant Preparations/pharmacology , Radiation-Protective Agents/pharmacology , Animals , Animals, Outbred Strains , Betula/chemistry , Cholesterol Esters/chemistry , Drug Evaluation, Preclinical , Genistein/chemical synthesis , Genistein/chemistry , Genistein/toxicity , Male , Metal Nanoparticles/chemistry , Metal Nanoparticles/toxicity , Mice , Particle Size , Pentacyclic Triterpenes/chemistry , Plant Bark/chemistry , Plant Preparations/chemical synthesis , Plant Preparations/chemistry , Plant Preparations/toxicity , Radiation Injuries, Experimental/drug therapy , Radiation-Protective Agents/chemical synthesis , Radiation-Protective Agents/chemistry , Radiation-Protective Agents/toxicity , Random Allocation , Survival Analysis , Treatment Outcome , Triterpenes/chemistry
9.
Clin Microbiol Infect ; 21(12): 1084-92, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26348263

ABSTRACT

Multidrug-resistant tuberculosis is a major issue worldwide; however, accessibility to drug susceptibility testing (DST) is still limited in developing countries, owing to high costs and complexity. We developed a proportion method on 12-well microplates for DST. The assay reduced the time to results to <12 days and <10 days when bacterial growth was checked with the naked eye or a microscope, respectively. Comparison with the Canetti-Grosset method showed that the results of the two assays almost overlapped (kappa index 0.98 (95% CI 0.91-1.00) for isoniazid, rifampicin, streptomycin; and kappa index 0.92 (95% CI 0.85-0.99) for ethambutol). The sequencing of genes involved in drug resistance showed similar level of phenotype-genotype agreement between techniques. Finally, measurement of the MICs of rifampicin and ethambutol suggests that the currently used critical ethambutol concentration should be revised, and that the current molecular drug susceptibility tests for rifampicin need to be re-evaluated, as in vitro rifampicin-sensitive isolates could harbour drug resistance-associated mutation(s).


Subject(s)
Antitubercular Agents/pharmacology , Microbial Sensitivity Tests/methods , Mycobacterium tuberculosis/drug effects , Tuberculosis, Multidrug-Resistant/microbiology , Agar , Disease Susceptibility , Drug Resistance, Multiple, Bacterial , Ethambutol/pharmacology , Genes, Bacterial , Humans , Mycobacterium tuberculosis/genetics , Rifampin/pharmacology
10.
Bioorg Khim ; 41(2): 185-94, 2015.
Article in Russian | MEDLINE | ID: mdl-26165125

ABSTRACT

This work is devoted to the study of nanoparticles based on amphiphilic meso-arylporphyrins and spherical amorphous nanoparticles (SANp), consisting of birch bark triterpenoids mixture. Nanoparticles were investigated by electron microscopy, dynamic light scattering, UV spectroscopy and fluorimetry. It was shown the efficiency of the inclusion of porphyrin sensitizer to the nanoparticles and the use of these nanoparticles as drug delivery system.


Subject(s)
Drug Carriers/chemistry , Nanoparticles/chemistry , Porphyrins/chemistry , Terpenes/chemistry , Particle Size
11.
Nanotechnology ; 25(48): 485205, 2014 Dec 05.
Article in English | MEDLINE | ID: mdl-25396303

ABSTRACT

Using a step-graded (SG) buffer structure via metal-organic chemical vapor deposition, we demonstrate a high suitability of In0.5Ga0.5As epitaxial layers on a GaAs substrate for electronic device application. Taking advantage of the technique's precise control, we were able to increase the number of SG layers to achieve a fairly low dislocation density (∼10(6) cm(-2)), while keeping each individual SG layer slightly exceeding the critical thickness (∼80 nm) for strain relaxation. This met the demanded but contradictory requirements, and even offered excellent scalability by lowering the whole buffer structure down to 2.3 µm. This scalability overwhelmingly excels the forefront studies. The effects of the SG misfit strain on the crystal quality and surface morphology of In0.5Ga0.5As epitaxial layers were carefully investigated, and were correlated to threading dislocation (TD) blocking mechanisms. From microstructural analyses, TDs can be blocked effectively through self-annihilation reactions, or hindered randomly by misfit dislocation mechanisms. Growth conditions for avoiding phase separation were also explored and identified. The buffer-improved, high-quality In0.5Ga0.5As epitaxial layers enabled a high-performance, metal-oxide-semiconductor capacitor on a GaAs substrate. The devices displayed remarkable capacitance-voltage responses with small frequency dispersion. A promising interface trap density of 3 × 10(12) eV(-1) cm(-2) in a conductance test was also obtained. These electrical performances are competitive to those using lattice-coherent but pricey InGaAs/InP systems.

12.
Comput Inform Nurs ; 29(2 Suppl): TC3-8, 2011 Feb.
Article in English | MEDLINE | ID: mdl-21372643

ABSTRACT

Traditional approaches to patient-reported outcomes diaries have been largely paper based. However, paper-based approaches have inherent inefficiencies such as an inability to communicate the entries in real time to the healthcare team, issues related to transport and mobility, and no tailored output related to what is entered. Traditional paper-based approaches also lack the ability to prompt users at regular intervals to record data. This lack of prompting may lead to delays in entering symptoms and exercises (diary hoarding). Electronic mobile devices have addressed some of these limitations. However, until recently these electronic devices have not been able to deliver the data in real time, thus limiting the ability of the care team to interact and respond. With the emergence of wireless mobile devices, which provide real-time linkages between the patient and the researchers, these limitations are largely eliminated. Yet, it is unclear (whether diary hoarding still occurs and) whether prompts are effective in reducing hoarding over the course of many months. The purpose of this analysis was to conduct a summative evaluation of 7474 automated prompts sent to participants with chronic obstructive pulmonary disease (n = 19). These participants were provided with mobile devices for logging exercise and symptom data over a 6-month period as part of a clinical trial. We found a marginal association between length in the study and delay in submission of exercise and symptom data in response to electronic prompts. Factors associated with delayed response to the prompts included older age, limited computer skills, and reports of no exercise. We recommend that future investigators who are using mobile devices in their research pay careful attention to usability issues as well as strategies that might keep patients engaged and motivated.

13.
Comput Inform Nurs ; 29(2): 75-80, 2011 Feb.
Article in English | MEDLINE | ID: mdl-21048498

ABSTRACT

Traditional approaches to patient-reported outcomes diaries have been largely paper based. However, paper-based approaches have inherent inefficiencies such as an inability to communicate the entries in real time to the healthcare team, issues related to transport and mobility, and no tailored output related to what is entered. Traditional paper-based approaches also lack the ability to prompt users at regular intervals to record data. This lack of prompting may lead to delays in entering symptoms and exercises (diary hoarding). Electronic mobile devices have addressed some of these limitations. However, until recently these electronic devices have not been able to deliver the data in real time, thus limiting the ability of the care team to interact and respond. With the emergence of wireless mobile devices, which provide real-time linkages between the patient and the researchers, these limitations are largely eliminated. Yet, it is unclear (whether diary hoarding still occurs and) whether prompts are effective in reducing hoarding over the course of many months. The purpose of this analysis was to conduct a summative evaluation of 7474 automated prompts sent to participants with chronic obstructive pulmonary disease (n = 19). These participants were provided with mobile devices for logging exercise and symptom data over a 6-month period as part of a clinical trial. We found a marginal association between length in the study and delay in submission of exercise and symptom data in response to electronic prompts. Factors associated with delayed response to the prompts included older age, limited computer skills, and reports of no exercise. We recommend that future investigators who are using mobile devices in their research pay careful attention to usability issues as well as strategies that might keep patients engaged and motivated.


Subject(s)
Automation , Exercise , Microcomputers , Pulmonary Disease, Chronic Obstructive/physiopathology , Humans , Self Care
14.
Phys Rev Lett ; 103(15): 157001, 2009 Oct 09.
Article in English | MEDLINE | ID: mdl-19905659

ABSTRACT

Ultrathin amorphous Bi films, patterned with a nanohoneycomb array of holes, can exhibit an insulating phase with transport dominated by the incoherent motion of Cooper pairs (CP) of electrons between localized states. Here, we show that the magnetoresistance (MR) of this Cooper pair insulator (CPI) phase is positive and grows exponentially with decreasing temperature T, for T well below the pair formation temperature. It peaks at a field estimated to be sufficient to break the pairs and then decreases monotonically into a regime in which the film resistance assumes the T dependence appropriate for weakly localized single electron transport. We discuss how these results support proposals that the large MR peaks in other unpatterned, ultrathin film systems disclose a CPI phase and provide new insight into the CP localization.

15.
Biomaterials ; 25(5): 865-76, 2004 Feb.
Article in English | MEDLINE | ID: mdl-14609675

ABSTRACT

Ti-6Al-4V implants formed with a sintered porous surface for implant fixation by bone ingrowth were prepared with or without the addition of a thin surface layer of calcium phosphate (Ca-P) formed using a sol-gel coating technique over the porous surface. The implants were placed transversely across the tibiae of 17 rabbits. Implanted sites were allowed to heal for 2 weeks, after which specimens were retrieved for morphometric assessment using backscattered scanning electron microscopy and quantitative image analysis. Bone formation along the porous-structured implant surface, was measured in relation to the medial and lateral cortices as an indication of implant surface osteoconductivity. The Absolute Contact Length measurements of endosteal bone growth along the porous-surfaced zone were greater with the Ca-P-coated implants compared to the non-Ca-P-coated implants. The Ca-P-coated implants also displayed a trend towards a significant increase in the area of bone ingrowth (Bone Ingrowth Fraction). Finally, there was significantly greater bone-to-implant contact within the sinter neck regions of the Ca-P-coated implants.


Subject(s)
Bone Substitutes/chemistry , Calcium Phosphates/chemistry , Crystallization/methods , Osseointegration/physiology , Prostheses and Implants , Tibia/surgery , Tibia/ultrastructure , Titanium/chemistry , Alloys , Animals , Coated Materials, Biocompatible , Freeze Fracturing , Image Interpretation, Computer-Assisted/methods , Male , Materials Testing/methods , Microscopy, Electron, Scanning , Osteogenesis/physiology , Phase Transition , Porosity , Rabbits , Surface Properties , Tibia/physiology
16.
J Psychopharmacol ; 16(2): 145-52, 2002 Jun.
Article in English | MEDLINE | ID: mdl-12095073

ABSTRACT

Clinical augmentation strategies have shown that some improvement in antidepressant efficacy can be achieved by combining the beta-adrenergic/serotonin (5-HT)1A/1B receptor antagonist (+/-)pindolol with a selective serotonin reuptake inhibitor (SSRI). This has lead to the hypothesis that a combination of a 5-HT1A receptor antagonist with an SSRI will lead to a faster onset of antidepressant action. Although there is a significant accumulation of acute preclinical data supporting this rationale, until recently, there have been no investigations examining the chronic effects of combining an SSRI with a 5-HT1A receptor antagonist. Here, we determined the chronic effects of fluoxetine (10 mg/kg o.d.), administered in combination with the selective 5-HT1A receptor antagonist WAY-100635 (1 mg/kg b.i.d.), on serotonergic neurotransmission in the frontal cortex using in-vivo microdialysis. Following chronic administration of fluoxetine +/- WAY-100635, functional changes in serotonergic neurotransmission, as well as 5-HT1A autoreceptors, were assessed by administering fluoxetine or (+/-) 8-hydroxy-2-(di-n-propylamino)tetralin [(+/-) 8-OH-DPAT] 24 h after the last chronic dose. Chronic administration of WAY-100635 alone produced no detectable change in the functional status of the 5-HT1A receptor. However, fluoxetine alone produced a time-dependent adaptation in serotonergic transmission such that fluoxetine (acutely administered on day 15) was able to produce a two-fold increase in extracellular 5-HT levels but the decrease in response to 8-OH-DPAT was completely attenuated. These data indicate that the fluoxetine-induced adaptation was mediated by desensitization of the 5-HT1A receptor. WAY-100635 given chronically in combination with fluoxetine blocked the SSRI-induced desensitization of the 5-HT1A receptor. Furthermore, chronic treatment with this combination produced no tolerance in terms of its ability to acutely increase forebrain 5-HT levels. These data suggest that augmentation of an SSRI by combined pharmacotherapy with a 5-HT1A antagonist would be effective upon prolonged exposure.


Subject(s)
Antidepressive Agents, Second-Generation/pharmacology , Fluoxetine/pharmacology , Piperazines/pharmacology , Prefrontal Cortex/physiology , Pyridines/pharmacology , Serotonin Antagonists/pharmacology , Serotonin/physiology , Synaptic Transmission/drug effects , 8-Hydroxy-2-(di-n-propylamino)tetralin/pharmacology , Animals , Extracellular Space/drug effects , Extracellular Space/metabolism , Male , Microdialysis , Prefrontal Cortex/drug effects , Rats , Rats, Sprague-Dawley , Receptors, Serotonin/drug effects , Receptors, Serotonin, 5-HT1 , Serotonin Receptor Agonists/pharmacology
17.
Neuropsychopharmacology ; 25(5): 662-8, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11682249

ABSTRACT

Preclinical evidence has suggested a possible role for the 5-HT(6) receptor in the treatment of cognitive dysfunction. However, currently there is little neurochemical evidence suggesting the mechanism(s) which may be involved. Using the selective 5-HT(6) antagonist SB-271046 and in vivo microdialysis, we have evaluated the effects of this compound on the modulation of basal neurotransmitter release within multiple brain regions of the freely moving rat. SB-271046 produced no change in basal levels of dopamine (DA), norepinephrine (NE) or 5-HT in the striatum, frontal cortex, dorsal hippocampus or nucleus accumbens. Similarly, this compound had no effect on excitatory neurotransmission in the striatum or nucleus accumbens. Conversely, SB-271046 produced 3- and 2-fold increases in extracellular glutamate levels in both frontal cortex and dorsal hippocampus, respectively. These effects were completely attenuated by infusion of tetrodotoxin but unaffected by the muscarinic antagonist, atropine. Here we demonstrate for the first time the selective enhancement of excitatory neurotransmission by SB-271046 in those brain regions implicated in cognitive and memory function, and provide mechanistic evidence in support of a possible therapeutic role for 5-HT(6) receptor antagonists in the treatment of cognitive and memory dysfunction.


Subject(s)
Excitatory Amino Acids/physiology , Hippocampus/physiology , Prefrontal Cortex/physiology , Receptors, Serotonin/drug effects , Serotonin Antagonists/pharmacology , Sulfonamides/pharmacology , Synaptic Transmission/drug effects , Thiophenes/pharmacology , Animals , Atropine/pharmacology , Dopamine/metabolism , Extracellular Space/drug effects , Extracellular Space/metabolism , Glutamic Acid/metabolism , Hippocampus/drug effects , Male , Microdialysis , Muscarinic Antagonists/pharmacology , Norepinephrine/metabolism , Prefrontal Cortex/drug effects , Rats , Rats, Sprague-Dawley , Serotonin/metabolism , Tetrodotoxin/pharmacology
18.
Blood ; 98(8): 2489-97, 2001 Oct 15.
Article in English | MEDLINE | ID: mdl-11588047

ABSTRACT

Mature dendritic cells (DCs), in addition to providing costimulation, can define the Th1, in contrast to the Th2, nature of a T-cell response through the production of cytokines and chemokines. Because calcium signaling alone causes rapid DC maturation of both normal and transformed myeloid cells, it was evaluated whether calcium-mobilized DCs polarize T cells toward a Th1 or a Th2 phenotype. After human monocytes were cultured for 24 hours in serum-free medium and granulocyte-macrophage colony-stimulating factor to produce immature DCs, additional overnight culture with either calcium ionophore (CI) or interferon gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), and soluble CD40L resulted in phenotypically mature DCs that produced interleukin-8 (IL-8) and displayed marked expression of CD80, CD86, CD40, CD54, CD83, DC-LAMP, and RelB. DCs matured by IFN-gamma, TNF-alpha, and soluble CD40L were additionally distinguished by undetectable CD4 expression, marked secretion of IL-12, IL-6, and MIP-1beta, and preferential ability to promote Th1/Tc1 characteristics during T-cell sensitization. In contrast, DCs matured by CI treatment were distinguished by CD4 expression, modest or absent levels of IL-12, IL-6, and MIP-1beta, and preferential ability to promote Th2/Tc2 characteristics. Calcium signaling selectively antagonized IL-12 production by mature DCs activated with IFN-gamma, TNF-alpha, and soluble CD40L. Although the activation of DCs by calcium signals is largely mediated through calcineurin phosphatase, the inhibition of IL-12 production by calcium signaling was independent of this enzyme. Naturally occurring calcium fluxes in immature DCs, therefore, negatively regulate Dc1 differentiation while promoting Dc2 characteristics and Th2/Tc2 polarization. Calcium-mobilized DCs may have clinical usefulness in treating disease states with excessive Th1/Tc1 activity, such as graft-versus-host disease or autoimmunity.


Subject(s)
Calcium Signaling/physiology , Dendritic Cells/immunology , Immunoglobulins/immunology , Interleukin-12/antagonists & inhibitors , Membrane Glycoproteins/immunology , T-Lymphocyte Subsets/immunology , T-Lymphocytes/immunology , Th2 Cells/immunology , Antigens, CD/immunology , CD8-Positive T-Lymphocytes/immunology , Cells, Cultured , Coculture Techniques , Cytokines/analysis , Enzyme-Linked Immunosorbent Assay , Flow Cytometry , Humans , Leukapheresis , Monocytes/immunology , NF-kappa B/antagonists & inhibitors , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins/metabolism , Transcription Factor RelB , Transcription Factors/genetics , Transcription Factors/metabolism , CD83 Antigen
19.
Br J Pharmacol ; 130(4): 797-804, 2000 Jun.
Article in English | MEDLINE | ID: mdl-10864885

ABSTRACT

Using in vivo microdialysis in the frontal cortex of the freely moving rat we evaluated the effects of chronic treatment with the serotonin specific reuptake inhibitor (SSRI) fluoxetine in the presence and absence of the 5-HT(1A)/beta-adrenergic antagonist (+/-)pindolol. Chronic vehicle treated animals produced no significant response to a challenge with fluoxetine (10 mg kg(-1)) on day 8 and 15. Alternatively, a significant (P<0.05) decrease in extracellular 5-HT was observed in control animals upon challenge with the 5-HT(1A) agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT; 0.03 and 0.1 mg kg(-1)). Conversely, animals treated with fluoxetine (10 mg kg(-1) o.d.) for 7 and 14 days produced a significant (P<0.05) 2 fold increase in extracellular 5-HT when challenged with fluoxetine (10 mg kg(-1)) on day 8 and 15. Moreover, no significant decrease in extracellular 5-HT was observed upon challenge with either dose of 8-OH-DPAT. Animals chronically treated with (+/-)pindolol (10 or 20 mg kg(-1) b.i.d.) produced a significant dose-related increase in extracellular 5-HT upon challenge with fluoxetine on day 15 only. Furthermore, both doses produced a significantly blunted response to the low dose challenge of 8-OH-DPAT (0.03 mg kg(-1)). In addition, 20 mg kg(-1) (+/-)pindolol treated animals also had no response to the higher 0.1 mg kg(-1) dose of 8-OH-DPAT. Animals treated for 14 days with a combination of (+/-)pindolol (10 or 20 mg kg(-1)) and fluoxetine were not significantly different from vehicle treated animals when challenged with fluoxetine or 8-OH-DPAT. Taken together it would therefore appear that although (+/-)pindolol alone has sufficient intrinsic activity to produce a desensitization of the 5-HT(1A) receptor, when given in combination with fluoxetine it is able to prevent the desensitization induced by not only fluoxetine but also itself. This may suggest that the clinical augmentation of antidepressant action by pindolol, when co-administered with a SSRI, is via antagonism of the 5-HT(1A) receptor.


Subject(s)
Fluoxetine/pharmacology , Pindolol/pharmacology , Selective Serotonin Reuptake Inhibitors/pharmacology , Serotonin Antagonists/pharmacology , 8-Hydroxy-2-(di-n-propylamino)tetralin/pharmacology , Animals , Dose-Response Relationship, Drug , Frontal Lobe/drug effects , Frontal Lobe/metabolism , Male , Microdialysis , Rats , Rats, Sprague-Dawley , Serotonin/metabolism , Serotonin Receptor Agonists/pharmacology , Time Factors
20.
J Immunother ; 23(3): 311-20, 2000.
Article in English | MEDLINE | ID: mdl-10838660

ABSTRACT

The authors previously showed that monocytes treated with calcium ionophore (CI) acquire characteristics of mature dendritic cells (DC) in part through a calcineurin-dependent pathway. In this study, the authors evaluated the ability of granulocyte-macrophage colony stimulating factor (GM-CSF), interleukin-2 (IL-2), and interleukin-12 (IL-12) alone or in combination with CI to induce DC characteristics in peripheral blood monocytes. Monocytes obtained by leukapheresis and countercurrent centrifugal elutriation were cultured with calcium, cytokines, or both, profiled by flow cytometry, and assessed for antigen uptake and sensitization of autologous CD8+ T cells to antigen. Monocytes treated with the combination of GM-CSF, IL-2, and IL-12 resulted in immunophenotypic and antigen uptake profiles typical of immature DC, including loss of surface CD14 expression, de novo low-level expression of B7.1, negligible CD83 expression, marked enhancement of CD40 and ICAM-1, and high major histocompatibility complex class I and II levels. A high level of antigen uptake by macro-pinocytosis was observed. In contrast, CI treatment significantly up-regulates B7.1, B7.2, CD40, CD54, and CD83 and substantially down-regulates CD14 and macro-pinocytosis, a profile consistent with mature DC. Many CI-induced modulations, but none resulting from cytokine treatment alone, were inhibited by the calcineurin phosphatase inhibitor cyclosporin A. Compared with monocytes treated with CI alone, combined treatment of monocytes with GM-CSF, IL-2, IL-12, and CI augmented B7.1 and CD83 expression and enhanced sensitization of autologous CD8+ T cells to melanoma-antigen-derived peptides. These results suggest that several independent pathways of DC activation can cooperatively enhance the function of monocyte-derived DC.


Subject(s)
Dendritic Cells/immunology , Granulocyte-Macrophage Colony-Stimulating Factor/pharmacology , Interleukin-12/pharmacology , Interleukin-2/pharmacology , Ionophores/pharmacology , Antigens, CD/immunology , B7-1 Antigen/immunology , B7-2 Antigen , Bone Marrow Cells/cytology , CD8-Positive T-Lymphocytes/immunology , Calcium , Cells, Cultured , Cyclosporine/pharmacology , Dendritic Cells/drug effects , Flow Cytometry , Humans , Immunoglobulins/immunology , Lipopolysaccharide Receptors/immunology , Membrane Glycoproteins/immunology , Monocytes/drug effects , Monocytes/immunology , Pinocytosis/drug effects , CD83 Antigen
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