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1.
Plant Dis ; 2023 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-36627798

RESUMEN

Pyrethrum (Tanacetum cinerariifolium (Trevir.) Sch. Bip.) is grown to extract pyrethrins which are active ingredients for insecticides (Greenhill 2007). The Australian pyrethrum industry supplies over 50% of the world market. Surveys of Tasmanian crops in spring 2013, detected the presence of a fungus putatively identified as Itersonilia perplexans Derx. on foliage in 54 of 86 surveyed fields (Hay et al. 2015). This fungus was associated with necrotic leaf tips often spreading to encompass whole leaves. However, pathogenicity to pyrethrum was not confirmed. To isolate, tissue was excised from foliar lesions, surface sterilised using 0.4% NaClO, placed onto 2% water agar and incubated at 20°C for 5 days. Colonies were pure-cultured by hyphal-tip transfer onto potato-dextrose agar. Eleven isolates were cultured onto yeast mold agar (YMA) for 14 days at 15°C in the dark (Horita and Yasuoka 2002). Colonies were slow growing (1.9 to 2.3 mm/day) white to buff on both surfaces, with a darker center visible on lower surfaces. Mycelia were straight and hyaline with clamp connections at the septa. Squares transferred from the edge of YMA colonies onto microscope slides produced ballistoconidia that were aseptate, granular and lunate, kidney or lemon-shaped after 24 h. Ballistoconidia lengths and widths (n = 50/isolate) ranged from 14.6 to 20.4 µm and 10.0 to 13.6 µm. Chlamydospores were not observed. These observations were consistent with descriptions of I. perplexans (Koike and Tjosvold 2001; Liu et al. 2015). All 11 isolates were sequenced across the internal transcribed spacer (ITS) region of rDNA (ITS; primers V9G/ITS4; de Hoog and van den Ende 1998; White et al. 1990), and large (LSU; primers LROR/LR7; Rehner and Samuels 1995), and small (SSU; NS1/NS4; White et al. 1990) subunits of rDNA (Genbank accession nos. KU563626 to KU563658). The ITS (673 bp), SSU (1,047 bp) and LSU (1,318 bp) differed by 3, 1 and 0 bp, respectively, across isolates. Maximum parsimony and maximum likelihood analyses of a concatenated 3 loci alignment with Cystofilobasidiales representatives (Liu et al. 2015) placed all isolates and the I. perplexans ex-neotype strain CBS 363.85 within a single monophyletic clade with 100% bootstrap support. Two representative isolates are stored at the Plant Pathology Herbarium (accession nos. BRIP 57986 and 57987). Leaves of 46-day-old pyrethrum plants (n = 45), generated from surface sterilised seed, were inoculated with a 1.5 × 105 ballistoconidia/ml suspension (equal mix of eight isolates) and maintained between 10 and 22°C under a 12-h photoperiod for 14 days. Brown necrotic leaf tips, consistent with reported field symptoms were observed on 71% of plants and I. perplexans was recovered from 69% of symptomatic plants. For flower inoculations, pyrethrum plants were removed from fields as vegetative plants in spring and maintained in a greenhouse set at 20:14°C and 14:10 h day:night. Open flowers (10 per plant) were dipped into a 1.2 × 104 ballistoconidia/ml suspension mix of three isolates. Brown withered ray florets were observed on 10/12 plants 18 days post-inoculation, matching those described in petal blight of chrysanthemum (McRitchie et al. 1973). I. perplexans was re-isolated from 11/12 inoculated plants and 1 control plant (of 12) which exhibited the same symptoms. In both experiments, I. perplexans was identified based on its distinctive morphology. This confirms the pathogenicity of I. perplexans to both pyrethrum leaves and flowers.

2.
Palliat Med ; 36(10): 1469-1482, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36321587

RESUMEN

BACKGROUND: Falls are the third highest reported safety incident in Specialist Palliative Care in-patient settings and yet specific risk factors connected with falling and associated outcomes in this setting are poorly understood. AIM: To understand the key individualised risk factors leading to falls in specialist in-patient palliative care settings and understand the implications and outcomes for the patients who fall. DESIGN: A realist synthesis of the literature, reported following the Realist And Meta-narrative Evidence Syntheses: Evolving Standards (RAMESES) standards. DATA SOURCES: An iterative literature search was conducted across three recognised health collections as well as grey literature from policy, practice and other relevant areas. RESULTS: Falls taking place within in-patient specialist palliative care settings can cause significant harm to patients. The risk factors for these patients are multifaceted and often interlinked with underpinning complex realist mechanisms including a history of falls, the age of the person, impact of complex medications, improving functional status and the presence of delirium. CONCLUSION: In-patients in specialist palliative care settings are at risk of falling and this is multifactorial with complex reasoning mechanisms underpinning the identified risks. There is a significant impact of a fall in this cohort of patients with many sustaining serious harm, delayed discharge and both physical and psychological impacts.


Asunto(s)
Accidentes por Caídas , Cuidados Paliativos , Humanos
3.
Adv Mater ; 34(44): e2205674, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-36073657

RESUMEN

Single-atom catalysts (SACs) exhibit unparalleled atomic utilization and catalytic efficiency, yet it is challenging to modulate SACs with highly dispersed single-atoms, mesopores, and well-regulated coordination environment simultaneously and ultimately maximize their catalytic efficiency. Here, a generalized strategy to construct highly active ferric-centered SACs (Fe-SACs) is developed successfully via a biomineralization strategy that enables the homogeneous encapsulation of metalloproteins within metal-organic frameworks (MOFs) followed by pyrolysis. The results demonstrate that the constructed metalloprotein-MOF-templated Fe-SACs achieve up to 23-fold and 47-fold higher activity compared to those using metal ions as the single-atom source and those with large mesopores induced by Zn evaporation, respectively, as well as up to a 25-fold and 1900-fold higher catalytic efficiency compared to natural enzymes and natural-enzyme-immobilized MOFs. Furthermore, this strategy can be generalized to a variety of metal-containing metalloproteins and enzymes. The enhanced catalytic activity of Fe-SACs benefits from the highly dispersed atoms, mesopores, as well as the regulated coordination environment of single-atom active sites induced by metalloproteins. Furthermore, the developed Fe-SACs act as an excellent and effective therapeutic platform for suppressing tumor cell growth. This work advances the development of highly efficient SACs using metalloproteins-MOFs as a template with diverse biotechnological applications.


Asunto(s)
Estructuras Metalorgánicas , Metaloproteínas , Estructuras Metalorgánicas/química , Biocatálisis , Catálisis , Hierro/química
4.
Photochem Photobiol Sci ; 21(12): 2115-2126, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-35933640

RESUMEN

Photoreforming has been shown to accelerate the H2 evolution rate compared to water splitting due to thermodynamically favorable organic oxidation. In addition, the potential to simultaneously produce solar fuel and value-added chemicals is a significant benefit of photoreforming. To achieve an efficient and economically viable photoreforming process, the selection and design of an appropriate photocatalyst is essential. Carbon nitride is promising as a metal-free photocatalyst with visible light activity, high stability, and low fabrication cost. However, it typically exhibits poor photogenerated charge carrier dynamics, thereby resulting in low photocatalytic performance. Herein, we demonstrate improved carrier dynamics in urea-functionalized carbon nitride with in situ photodeposited Ni cocatalyst (Ni/Urea-CN) for ethanol photoreforming. In the presence of 1 mM Ni2+ precursor, an H2 evolution rate of 760.5 µmol h-1 g-1 and an acetaldehyde production rate of 888.2 µmol h-1 g-1 were obtained for Ni/Urea-CN. The enhanced activity is ascribed to the significantly improved carrier dynamics in Urea-CN. The ability of oxygen moieties in the urea group to attract electrons and to increase the hole mobility via a positive shift in the valence band promotes an improvement in the overall carrier dynamics. In addition, high crystallinity and specific surface area of the Urea-CN contributed to accelerating charge separation and transfer. As a result, the electrons were efficiently transferred from Urea-CN to the Ni cocatalyst for H2 evolution while the holes were consumed during ethanol oxidation. The work demonstrates a means by which carrier dynamics can be tuned by engineering carbon nitride via edge functionalization.


Asunto(s)
Níquel , Urea , Etanol , Acetaldehído
5.
ACS Appl Mater Interfaces ; 13(42): 49916-49926, 2021 Oct 27.
Artículo en Inglés | MEDLINE | ID: mdl-34652901

RESUMEN

Photoreforming is a promising alternative to water splitting for H2 generation due to the favorable organic oxidation half-reaction and the potential to simultaneously produce solar fuel and value-added chemicals. Recently, carbon nitride has received significant attention as an inexpensive photocatalyst for the photoreforming process. However, the application of carbon nitride continues to be hampered by its poor photocatalytic performance. Herein, we report for the first time a synergistic modification of an in situ photodeposited Ni cocatalyst on carbon nitride via cyanamide functionalization and solid/liquid interfacial charge-induced activation using excess Ni2+ ions. Synergism between the cyanamide functionalization and charge-induced activation by the excess Ni2+ ions invokes enhanced activity, selectivity, and stability during ethanol photoreforming. A H2 evolution rate of 2.32 mmol h-1 g-1 in conjunction with an acetaldehyde production rate of 2.54 mmol h-1 g-1 was attained for the Ni/NCN-CN. The H2 evolution rate and elevated acetaldehyde selectivity (above 98%) remained consistent under prolonged light illumination. To understand the origin of the complementary promotional effects, the contributions of cyanamide groups and excess Ni2+ ions to selective ethanol photoreforming are decoupled and systematically investigated. The cyanamide functionality on carbon nitride was found to promote hole scavenging for the ethanol oxidation reaction, thereby enabling effective electron transfer to the Ni cocatalyst for H2 evolution. Concomitantly, excess Ni2+ ions remaining in solution created a positively charged environment on the photocatalyst surface, which improved charge carrier utilization and ethanol adsorption. The work highlights the importance of both carbon nitride functionality and charge on the photocatalyst surface in developing a selective photocatalytic reforming system.

6.
Health Policy Technol ; 9(4): 673-691, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32874853

RESUMEN

OBJECTIVES: To describe epidemiological data on cases of COVID-19 and the spread of Severe Acute Respiratory Syndrome Coronavirus 2 in the United Kingdom (UK), and the subsequent policy and technological response to the pandemic, including impact on healthcare, business and the economy. METHODS: Epidemiological, business and economic data were extracted from official government sources covering the period 31st January to 13th August 2020; healthcare system data up to end of June 2019. RESULTS: UK-wide COVID-19 cases and deaths were 313,798 and 46,706 respectively (472 cases and 70 deaths per 100,000 population) by 12th August. There were regional variations in England, with London and North West (756 and 666 cases per 100,000 population respectively) disproportionately affected compared with other regions. As of 11th August, 13,618,470 tests had been conducted in the UK. Increased risk of mortality was associated with age (≥60 years), gender (male) and BAME groups. Since onset of the pandemic, emergency department attendance, primary care utilisation and cancer referrals and inpatient/outpatient referrals have declined; emergency ambulance and NHS111 calls increased. Business sectors most impacted are the arts, entertainment and recreation, followed by accommodation and food services. Government interventions aimed at curtailing the business and economic impact have been implemented, but applications for state benefits have increased. CONCLUSIONS: The impact of COVID-19 on the UK population, health system and economy has been profound. More data are needed to implement the optimal policy and technological responses to preventing further spikes in COVID-19 cases, and to inform strategic planning to manage future pandemics.

7.
Chem Commun (Camb) ; 56(11): 1709-1712, 2020 Feb 06.
Artículo en Inglés | MEDLINE | ID: mdl-31938788

RESUMEN

A novel, simple and controllable approach to designing NiO/Ni heterostructures supported on carbon for the hydrogen evolution reaction (HER) was utilized. By selectively oxidizing the Ni deposits, to differing degrees, the benefits of the NiO/Ni heterostructures were elucidated with the extent of Ni oxidation being a key factor in dictating performance.

8.
BMJ Open ; 9(12): e032925, 2019 12 11.
Artículo en Inglés | MEDLINE | ID: mdl-31831546

RESUMEN

OBJECTIVE: Around one in five emergency hospital admissions are affected by acute kidney injury (AKI). To address poor quality of care in relation to AKI, electronic alerts (e-alerts) are mandated across primary and secondary care in England and Wales. Evidence of the benefit of AKI e-alerts remains conflicting, with at least some uncertainty explained by poor or unclear implementation. The objective of this study was to identify factors relating to implementation, using Normalisation Process Theory (NPT), which promote or inhibit use of AKI e-alerts in secondary care. DESIGN: Mixed methods combining qualitative (observations, semi-structured interviews) and quantitative (survey) methods. SETTING AND PARTICIPANTS: Three secondary care hospitals in North East England, representing two distinct AKI e-alerting systems. Observations (>44 hours) were conducted in Emergency Assessment Units (EAUs). Semi-structured interviews were conducted with clinicians (n=29) from EAUs, vascular or general surgery or care of the elderly. Qualitative data were supplemented by Normalization MeAsure Development (NoMAD) surveys (n=101). ANALYSIS: Qualitative data were analysed using the NPT framework, with quantitative data analysed descriptively and using χ2 and Wilcoxon signed-rank test for differences in current and future normalisation. RESULTS: Participants reported familiarity with the AKI e-alerts but that the e-alerts would become more normalised in the future (p<0.001). No single NPT mechanism led to current (un)successful implementation of the e-alerts, but analysis of the underlying subconstructs identified several mechanisms indicative of successful normalisation (internalisation, legitimation) or unsuccessful normalisation (initiation, differentiation, skill set workability, systematisation). CONCLUSIONS: Clinicians recognised the value and importance of AKI e-alerts in their practice, although this was not sufficient for the e-alerts to be routinely engaged with by clinicians. To further normalise the use of AKI e-alerts, there is a need for tailored training on use of the e-alerts and routine feedback to clinicians on the impact that e-alerts have on patient outcomes.


Asunto(s)
Lesión Renal Aguda , Atención Primaria de Salud/métodos , Mejoramiento de la Calidad/organización & administración , Atención Secundaria de Salud , Lesión Renal Aguda/diagnóstico , Lesión Renal Aguda/epidemiología , Sistemas de Apoyo a Decisiones Clínicas , Inglaterra , Humanos , Nefrología/métodos , Nefrología/tendencias , Investigación Operativa , Sistemas de Atención de Punto , Investigación Cualitativa , Atención Secundaria de Salud/métodos , Atención Secundaria de Salud/organización & administración , Atención Secundaria de Salud/normas
9.
Bioresour Technol ; 279: 404-409, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-30712994

RESUMEN

The bio-oil obtained from a general pyrolysis process contains a higher concentration of oxygenated compounds and the resultant physical and chemical properties make it an unsuitable drop-in fuel. The oxygenated compounds in the bio-oil can be converted into hydrocarbons or less oxygenated compounds with the application of catalysts. This study demonstrated the bio-oil upgrading with the application of catalysts, comparing the catalytic effect of combined mono-metallic catalysts (Cu/zeolite and Ni/zeolite) and sole bi-metallic catalyst (CuNi/zeolite) on the composition of bio-oil and pyrolytic gases. The results demonstrated that in comparison to the combined mono-metallic catalysts, the sole bi-metallic catalyst showed better deoxygenation for all the oxygenated compounds and favoured the production of aliphatic hydrocarbons, whereas the combination of mono-metallic catalysts generated higher proportion of aromatic hydrocarbons in the bio-oil. In both cases, the catalysts equally favoured decarboxylation and decarbonylation reactions, as CO2/CO of approximately 1 was obtained during the pyrolysis process.


Asunto(s)
Biomasa , Cobre/farmacología , Níquel/farmacología , Zeolitas/farmacología , Biocombustibles , Catálisis , Calor , Hidrocarburos/metabolismo , Pirólisis/efectos de los fármacos
10.
Int J Mol Sci ; 20(2)2019 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-30669284

RESUMEN

Autophagy and the (PI3K-Akt/mTOR) signaling pathway play significant roles in glioblastoma multiforme (GBM) cell death and survival. Curcumin (Cur) has been reported to prevent several cancers, including GBM. However, the poor solubility and limited bioavailability of natural Cur limits its application in preventing GBM growth. Previously, we have shown the greater apoptotic and anti-carcinogenic effects of solid lipid Cur particles (SLCP) than natural Cur in cultured GBM cells. Here, we compared the autophagic responses on cultured U-87MG, GL261, F98, C6-glioma, and N2a cells after treatment with Cur or SLCP (25 µM for 24 h). Different autophagy, mitophagy, and chaperone-mediated autophagy (CMA) markers, along with the PI3K-AKkt/mTOR signaling pathway, and the number of autophagy vacuoles were investigated after treatment with Cur and or SLCP. We observed increased levels of autophagy and decreased levels of mitophagy markers, along with inhibition of the PI3K-Akt/mTOR pathway after treatments with Cur or SLCP. Cell survival markers were downregulated, and cell death markers were upregulated after these treatments. We found greater effects in the case of SCLP-treated cells in comparison to Cur. Given that fewer effects were observed on C-6 glioma and N2a cells. Our results suggest that SLCP could be a safe and effective means of therapeutically modulating autophagy in GBM cells.


Asunto(s)
Autofagia/efectos de los fármacos , Curcumina/química , Curcumina/farmacología , Lípidos/química , Nanopartículas/química , Animales , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Biomarcadores Ambientales , Glioblastoma/metabolismo , Glioblastoma/patología , Humanos , Ratones , Mitofagia/efectos de los fármacos , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Ratas , Transducción de Señal/efectos de los fármacos , Serina-Treonina Quinasas TOR/metabolismo
11.
PLoS One ; 12(10): e0186311, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-29059213

RESUMEN

The multifunctional Ca2+/calmodulin-dependent protein kinase II (CaMKII) is a serine/threonine kinase important in transducing intracellular Ca2+ signals. While in vitro data regarding the role of CaMKII in the regulation of endothelial nitric oxide synthase (eNOS) are contradictory, its role in endothelial function in vivo remains unknown. Using two novel transgenic models to express CaMKII inhibitor peptides selectively in endothelium, we examined the effect of CaMKII on eNOS activation, NO production, vasomotor tone and blood pressure. Under baseline conditions, CaMKII activation was low in the aortic wall. Consistently, systolic and diastolic blood pressure, heart rate and plasma NO levels were unaltered by endothelial CaMKII inhibition. Moreover, endothelial CaMKII inhibition had no significant effect on NO-dependent vasodilation. These results were confirmed in studies of aortic rings transduced with adenovirus expressing a CaMKII inhibitor peptide. In cultured endothelial cells, bradykinin treatment produced the anticipated rapid influx of Ca2+ and transient CaMKII and eNOS activation, whereas CaMKII inhibition blocked eNOS phosphorylation on Ser-1179 and dephosphorylation at Thr-497. Ca2+/CaM binding to eNOS and resultant NO production in vitro were decreased under CaMKII inhibition. Our results demonstrate that CaMKII plays an important role in transient bradykinin-driven eNOS activation in vitro, but does not regulate NO production, vasorelaxation or blood pressure in vivo under baseline conditions.


Asunto(s)
Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/metabolismo , Óxido Nítrico Sintasa de Tipo III/metabolismo , Óxido Nítrico/metabolismo , Animales , Línea Celular , Humanos , Fosforilación
12.
Arterioscler Thromb Vasc Biol ; 35(12): 2594-604, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26449752

RESUMEN

OBJECTIVE: Emerging evidence suggests that methionine oxidation can directly affect protein function and may be linked to cardiovascular disease. The objective of this study was to define the role of the methionine sulfoxide reductase A (MsrA) in models of vascular disease and identify its signaling pathways. APPROACH AND RESULTS: MsrA was readily identified in all layers of the vascular wall in human and murine arteries. Deletion of the MsrA gene did not affect atherosclerotic lesion area in apolipoprotein E-deficient mice and had no significant effect on susceptibility to experimental thrombosis after photochemical injury. In contrast, the neointimal area after vascular injury caused by complete ligation of the common carotid artery was significantly greater in MsrA-deficient than in control mice. In aortic vascular smooth muscle cells lacking MsrA, cell proliferation was significantly increased because of accelerated G1/S transition. In parallel, cyclin D1 protein and cdk4/cyclin D1 complex formation and activity were increased in MsrA-deficient vascular smooth muscle cell, leading to enhanced retinoblastoma protein phosphorylation and transcription of E2F. Finally, MsrA-deficient vascular smooth muscle cell exhibited greater activation of extracellular signal-regulated kinase 1/2 that was caused by increased activity of the Ras/Raf/mitogen-activated protein kinase signaling pathway. CONCLUSIONS: Our findings implicate MsrA as a negative regulator of vascular smooth muscle cell proliferation and neointimal hyperplasia after vascular injury through control of the Ras/Raf/mitogen-activated protein kinase kinase/extracellular signal-regulated kinase 1/2 signaling pathway.


Asunto(s)
Enfermedades de la Aorta/enzimología , Aterosclerosis/enzimología , Traumatismos de las Arterias Carótidas/enzimología , Eliminación de Gen , Metionina Sulfóxido Reductasas/deficiencia , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Neointima , Transducción de Señal , Trombosis/enzimología , Animales , Aorta/enzimología , Aorta/patología , Enfermedades de la Aorta/genética , Enfermedades de la Aorta/patología , Apolipoproteínas E/deficiencia , Apolipoproteínas E/genética , Aterosclerosis/genética , Aterosclerosis/patología , Arterias Carótidas/enzimología , Arterias Carótidas/patología , Traumatismos de las Arterias Carótidas/genética , Traumatismos de las Arterias Carótidas/patología , Ciclo Celular , Proteínas de Ciclo Celular/metabolismo , Movimiento Celular , Proliferación Celular , Células Cultivadas , Modelos Animales de Enfermedad , Femenino , Humanos , Hiperplasia , Masculino , Metionina Sulfóxido Reductasas/genética , Ratones Endogámicos C57BL , Ratones Noqueados , Miocitos del Músculo Liso/enzimología , Miocitos del Músculo Liso/patología , Trombosis/sangre , Trombosis/genética , Factores de Tiempo , Quinasas raf/metabolismo , Proteínas ras/metabolismo
13.
PLoS One ; 9(4): e94641, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24743729

RESUMEN

Methane emitted by coal mine ventilation air (MVA) is a significant greenhouse gas. A mitigation strategy is the oxidation of methane to carbon dioxide, which is approximately twenty-one times less effective at global warming than methane on a mass-basis. The low non-combustible methane concentrations at high MVA flow rates call for a catalytic strategy of oxidation. A laboratory-scale coal-packed biofilter was designed and partially removed methane from humidified air at flow rates between 0.2 and 2.4 L min-1 at 30°C with nutrient solution added every three days. Methane oxidation was catalysed by a complex community of naturally-occurring microorganisms, with the most abundant member being identified by 16S rRNA gene sequence as belonging to the methanotrophic genus Methylocystis. Additional inoculation with a laboratory-grown culture of Methylosinus sporium, as investigated in a parallel run, only enhanced methane consumption during the initial 12 weeks. The greatest level of methane removal of 27.2±0.66 g methane m-3 empty bed h-1 was attained for the non-inoculated system, which was equivalent to removing 19.7±2.9% methane from an inlet concentration of 1% v/v at an inlet gas flow rate of 1.6 L min-1 (2.4 min empty bed residence time). These results show that low-cost coal packing holds promising potential as a suitable growth surface and contains methanotrophic microorganisms for the catalytic oxidative removal of methane.


Asunto(s)
Carbón Mineral , Filtración/métodos , Efecto Invernadero , Metano/aislamiento & purificación , Metano/metabolismo , Methylosinus/metabolismo , Ventilación , Contaminantes Atmosféricos/aislamiento & purificación , Contaminantes Atmosféricos/metabolismo , Biodegradación Ambiental , Dióxido de Carbono/metabolismo , Oxidación-Reducción
14.
Biomater Sci ; 2(1): 121-130, 2014 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-32481814

RESUMEN

A silica-based mesoporous nanosphere (MSN) controlled-release drug delivery system has been synthesized and characterized. The system uses l-cysteine derivatized gold nanoparticles (AuNPs), bound to the MSNs using Cu2+ as a bridging ion. The AuNPs serve as removable caps that hinder the release of drug molecules inside the amino functionalized MSN mesoporous framework. The modified MSNs themselves exhibit negligible cytotoxicity to living cells, as revealed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The drug delivery system requires one of two biological stimuli to trigger drug release. These stimuli are either: low pH (pH < 5); or elevated levels of adenosine triphosphate (ATP) (concentration > 4 mM). The feasibility of biologically controlled release was demonstrated through the stimuli-induced removal of the AuNP caps over the MSN releasing the anticancer drug doxorubicin. We envisage that this MSN system could play a significant role in developing new generations of controlled-release delivery vehicles.

15.
PLoS One ; 8(8): e71550, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23951185

RESUMEN

OBJECTIVE: Sustained hemodynamic stress mediated by high blood flow promotes arteriogenesis, the outward remodeling of existing arteries. Here, we examined whether Ca²âº/calmodulin-dependent kinase II (CaMKII) regulates arteriogenesis. METHODS AND RESULTS: Ligation of the left common carotid led to an increase in vessel diameter and perimeter of internal and external elastic lamina in the contralateral, right common carotid. Deletion of CaMKIIδ (CaMKIIδ-/-) abolished this outward remodeling. Carotid ligation increased CaMKII expression and was associated with oxidative activation of CaMKII in the adventitia and endothelium. Remodeling was abrogated in a knock-in model in which oxidative activation of CaMKII is abolished. Early after ligation, matrix metalloproteinase 9 (MMP9) was robustly expressed in the adventitia of right carotid arteries of WT but not CaMKIIδ-/- mice. MMP9 mainly colocalized with adventitial macrophages. In contrast, we did not observe an effect of CaMKIIδ deficiency on other proposed mediators of arteriogenesis such as expression of adhesion molecules or smooth muscle proliferation. Transplantation of WT bone marrow into CaMKIIδ-/- mice normalized flow-mediated remodeling. CONCLUSION: CaMKIIδ is activated by oxidation under high blood flow conditions and is required for flow-mediated remodeling through a mechanism that includes increased MMP9 expression in bone marrow-derived cells invading the arterial wall.


Asunto(s)
Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/metabolismo , Arteria Carótida Común/fisiología , Neovascularización Fisiológica , Animales , Trasplante de Médula Ósea , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/genética , Traumatismos de las Arterias Carótidas/diagnóstico por imagen , Traumatismos de las Arterias Carótidas/enzimología , Arteria Carótida Común/diagnóstico por imagen , Arteria Carótida Común/ultraestructura , Células Cultivadas , Activación Enzimática , Eliminación de Gen , Metaloproteinasa 9 de la Matriz/genética , Metaloproteinasa 9 de la Matriz/metabolismo , Ratones , Ratones Endogámicos C57BL , Oxidación-Reducción , Ultrasonografía , Regulación hacia Arriba
16.
Am J Physiol Heart Circ Physiol ; 302(10): H1953-64, 2012 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-22427508

RESUMEN

The multifunctional CaMKII has been implicated in vascular smooth muscle cell (VSMC) migration, but little is known regarding its downstream targets that mediate migration. Here, we examined whether CaMKII regulates migration through modulation of matrix metalloproteinase 9 (MMP9). Using CaMKIIδ(-/-) mice as a model system, we evaluated migration and MMP9 regulation in vitro and in vivo. After ligation of the common carotid artery, CaMKII was activated in the neointima as determined by oxidation and autophosphorylation. We found that MMP9 was robustly expressed in the neointima and adventitia of carotid-ligated wild-type (WT) mice but was barely detectable in CaMKIIδ(-/-) mice. The perimeter of the external elastic lamina, a correlate of migration-related outward remodeling, was increased in WT but not in CaMKIIδ(-/-) mice. Migration induced by serum, platelet-derived growth factor, and tumor necrosis factor-α (TNF-α) was significantly decreased in CaMKIIδ(-/-) as compared with WT VSMCs, but migration was rescued with adenoviral overexpression of MMP9 in CaMKIIδ(-/-) VSMCs. Likewise, overexpression of CaMKIIδ in CaMKIIδ(-/-) VSMCs increased migration, whereas an oxidation-resistant mutant of CaMKIIδ did not. TNF-α strongly induced CaMKII oxidation and autophosphorylation as well as MMP9 activity, mRNA, and protein levels in WT, but not in CaMKIIδ(-/-) VSMC. Surprisingly, TNF-α strongly induced MMP9 promoter activity in WT and CaMKIIδ(-/-) VSMC. However, the MMP9 mRNA stability was significantly decreased in CaMKIIδ(-/-) VSMC. Our data demonstrate that CaMKII promotes VSMC migration through posttranscriptional regulation of MMP9 and suggest that CaMKII effects on MMP9 expression may be a therapeutic pathway in vascular injury.


Asunto(s)
Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/fisiología , Movimiento Celular/fisiología , Metaloproteinasa 9 de la Matriz/fisiología , Músculo Liso Vascular/fisiología , Animales , Aorta/citología , Aorta/fisiología , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/deficiencia , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/genética , Movimiento Celular/efectos de los fármacos , Células Cultivadas , Femenino , Técnicas In Vitro , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Modelos Animales , Músculo Liso Vascular/citología , Factor de Crecimiento Derivado de Plaquetas/farmacología , ARN Mensajero/metabolismo , Factor de Necrosis Tumoral alfa/farmacología
17.
Radiol Manage ; 32(3): 28-33; quiz 34-5, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-22276376

RESUMEN

There are two components of cardiac CT discussed in this article: coronary artery calcium scoring (CACS) and coronary computed tomography angiography (CCTA).The distinctive advantages of each CT examination are outlined. In order to ensure a successful cardiac CT program, it is imperative that imaging facilities market their cardiac CT practices effectively in order to gain a competitive advantage in this valuable market share. If patients receive quality care by competent individuals, they are more likely to recommend the facility's cardiac CT program. Satisfied patients will also be more willing to come back for any further testing.


Asunto(s)
Calcinosis/diagnóstico por imagen , Enfermedades Cardiovasculares/diagnóstico por imagen , Angiografía Coronaria , Comercialización de los Servicios de Salud , Tomografía Computarizada por Rayos X , Humanos , Indiana , Estudios de Casos Organizacionales
18.
J Hazard Mater ; 161(2-3): 657-62, 2009 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-18486329

RESUMEN

The function of iron (ferric (Fe(III)) and ferrous (Fe(II))) in the hexavalent chromium (Cr(VI)) reduction mechanism by bacteria in municipal landfill leachate (MLL) was assessed. Evidence of an "electron shuttle" mechanism was observed, whereby the Cr(VI) was reduced to trivalent chromium (Cr(III)) by Fe(II) with the resulting Fe(III) bacterially re-reduced to Fe(II). Typically, investigations on this electron shuttle mechanism have been performed in an artificial medium. As MLL comprises an elaborate mixture of bacteria, humic materials and organic and inorganic species, additional complexities were evident within the cycle in this study. Bioavailability of the Fe(III) for bacterial reduction, availability of bacterially produced Fe(II) for chemical Cr(VI) reduction and hydrolysis of Fe(II) and Fe(III) become prevalent during each phase of the shuttle cycle when MLL is present. Each of these factors contributes to the overall rate of bacterial Cr(VI) reduction in this media. This work highlights the need to consider local environmental conditions when assessing the bacterial reduction of Cr(VI).


Asunto(s)
Cromo/química , Hierro/química , Eliminación de Residuos/métodos , Contaminantes Químicos del Agua/análisis , Disponibilidad Biológica , Cromo/análisis , Concentración de Iones de Hidrógeno , Residuos Industriales , Modelos Químicos , Compuestos Orgánicos , Contaminantes del Suelo , Sulfatos/química , Eliminación de Residuos Líquidos , Purificación del Agua/métodos
19.
Environ Toxicol Chem ; 28(3): 595-602, 2009 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-18939894

RESUMEN

Diesel is a complex mixture containing polycyclic aromatic hydrocarbons, which persist after a spill, pass readily from water into tissues, and are toxic to early life stages of fish. The bioavailability and chronic toxicity of hydrocarbons dissolved into water from floating diesel (water-accommodated fraction) and chemically dispersed diesel (chemically enhanced water-accommodated fraction) were measured by the extent of ethoxyresorufin-O-deethylase (EROD) induction in juvenile rainbow trout (Oncorhynchus mykiss) and by the severity of blue sac disease in embryos. The water-accommodated fraction of floating diesel was virtually nontoxic to embryos at nominal concentrations up to 1,000 mg/L, causing only small weight changes. Liver EROD induction in juvenile trout was only observed at the highest nominal water-accommodated fraction concentration (10,000 mg/L). Chemical dispersion increased the bioavailability and toxicity of diesel to trout by 100-fold. Diesel chemically enhanced water-accommodated fraction induced EROD activity, caused blue sac disease, and impaired development and growth of embryonic trout at nominal concentrations as low as 10 mg/L; 88% mortality occurred at 100 mg/L. However, when total hydrocarbon concentrations were measured, differences between dispersed and undispersed diesel disappeared, with a median lethal concentration of 8 mg/L of total hydrocarbons and sublethal median effective concentrations ranging from 1.3 to 6.1 mg/L. Dispersion of diesel by high-energy mechanical mixing was recently reported to cause acute lethality to juvenile trout between 40 and 200 mg/L. Therefore, dispersion of oil by any means increases the bioavailability and apparent toxicity of diesel to fish embryos without changing the toxicity of its components. Nevertheless, in an actual spill, dispersion of diesel increases the effects of oil on fish populations.


Asunto(s)
Restauración y Remediación Ambiental/métodos , Gasolina/análisis , Gasolina/toxicidad , Oncorhynchus mykiss/metabolismo , Animales , Disponibilidad Biológica
20.
Am J Physiol Gastrointest Liver Physiol ; 291(2): G318-30, 2006 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16574993

RESUMEN

We investigated the effects of PKC-stimulating 12-deoxyphorbol 13-phenylacetate 20-acetate (DOPPA) and phorbol 12-myristate 13-acetate (PMA) phorbol esters on cAMP-dependent, forskolin (FSK)-stimulated, short-circuit Cl- current (ISC-cAMP) generation by colonocyte monolayers. These agonists elicited different actions depending on their dose and incubation time; PMA effects at the onset (<5 min) were independent of cAMP agonist and were characterized by transient anion-dependent transcellular and apical membrane ISC generation. DOPPA failed to elicit similar responses. Whereas chronic (24 h) exposure to both agents inhibited FSK-stimulated transcellular and apical membrane ISC-cAMP, the effects of DOPPA were more complex: this conventional PKC-beta-specific agonist also stimulated Ba2+-sensitive basolateral membrane-dependent facilitation of transcellular ISC-cAMP. PMA did not elicit a similar phenomenon. Prolonged exposure to high-dose PMA but not DOPPA led to apical membrane ISC-cAMP recovery. Changes in PKC alpha-, beta1-, gamma-, and epsilon-isoform membrane partitioning and expression correlated with these findings. PMA-induced transcellular ISC correlated with PKC-alpha membrane association, whereas low doses of both agents inhibited transcellular and apical membrane ISC-cAMP, increased PKC-beta1, decreased PKC-beta2 membrane association, and caused reciprocal changes in isoform mass. During the apical membrane ISC-cAMP recovery after prolonged high-dose PMA exposure, an almost-complete depletion of cellular PKC-beta1 and a significant reduction in PKC-epsilon mass occurred. Thus activated PKC-beta1 and/or PKC-epsilon prevented, whereas activated PKC-alpha facilitated, apical membrane ISC-cAMP. PKC-beta-dependent augmentation of transcellular ISC-cAMP at the level of the basolateral membrane demonstrated that transport events with geographically distinct subcellular membranes can be independently regulated by the PKC beta-isoform.


Asunto(s)
Colon/fisiología , AMP Cíclico/metabolismo , Potenciales de la Membrana/fisiología , Proteína Quinasa C/metabolismo , Activación Enzimática , Células HT29 , Humanos , Activación del Canal Iónico/fisiología , Proteína Quinasa C beta
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