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1.
Nanotechnology ; 32(42)2021 Jul 26.
Article in English | MEDLINE | ID: mdl-34214992

ABSTRACT

This work presents a gas-phase approach for the synthesis of Cu2O/TiO2powder-based photocatalysts using atomic layer deposition (ALD). The process is carried out in a fluidized bed reactor working at atmospheric pressure using (trimethylvinylsilyl)-hexafluoroacetulacetonate copper(I) as the Cu-precursor and H2O vapor as the oxidizer. The saturating regime of the chemical reactions and the linear growth of ALD are achieved. In combination with the unsaturated regime, the ALD approach enables the deposition of ultrasmall Cu2O clusters with average diameters in the range of 1.3-2.0 nm, narrow particle size distributions and tunable Cu2O loadings on P25 TiO2nanoparticles. The photocatalytic performance of Cu2O/TiO2photocatalysts is investigated by the degradation of organic dyes, including Rhodamine B (RhB), methyl orange, and methylene blue; the results demonstrate that the surface modification of TiO2nanoparticles by Cu2O nanoclusters significantly enhances the photocatalytic activity of TiO2. This is attributed to the efficient charge transfer between Cu2O and TiO2that reduces the charge recombination. The photocatalytic reaction mechanism is further investigated for the degradation of RhB, revealing the dominating role of holes, which contribute to both direct hole oxidation and indirect oxidation (i.e. via the formation of hydroxyl radicals). Our approach provides a fast, scalable and efficient process to deposit ultrasmall Cu2O clusters in a controllable fashion for surface engineering and modification.

2.
J Cardiothorac Vasc Anesth ; 34(8): 2028-2035, 2020 Aug.
Article in English | MEDLINE | ID: mdl-32241678

ABSTRACT

This paper reviews the past 50 years of liver transplantation in children from the perspective of patient demographics, perioperative patient management, surgical techniques, immunosuppression and patient outcomes.


Subject(s)
Liver Transplantation , Child , Humans , Immunosuppression Therapy
3.
J Aging Health ; 32(7-8): 708-723, 2020.
Article in English | MEDLINE | ID: mdl-31130055

ABSTRACT

Objective: Hospital use increases in the last 3 months of life. We aimed to examine its association with where people live and its variation across a large health jurisdiction. Methods: We studied a number of emergency department presentations and days spent in hospital, and in-hospital deaths among decedents who were hospitalized within 30 days of death across 153 areas in New South Wales (NSW), Australia, during 2010-2015. Results: Decedents' demographics and health status were associated with hospital use. Primary care and aged care supply had no or minimal influence, as opposed to the varying effects of areal factors-socioeconomic status, remoteness, and distance to hospital last admitted. Overall, there was an approximate 20% difference in hospital use by decedents across areas. In all, 18% to 57% of areas had hospital use that differed from the average. Discussion: The observed disparity can inform targeted local efforts to strengthen the use of community care services and reduce the burden of end-of-life care on hospitals.


Subject(s)
Emergency Service, Hospital/statistics & numerical data , Patient Acceptance of Health Care/statistics & numerical data , Terminal Care , Aged , Aged, 80 and over , Female , Hospitalization/statistics & numerical data , Humans , Male , Medical Overuse/prevention & control , New South Wales/epidemiology , Retrospective Studies , Socioeconomic Factors , Terminal Care/methods , Terminal Care/statistics & numerical data
4.
BMJ Support Palliat Care ; 10(3): e27, 2020 Sep.
Article in English | MEDLINE | ID: mdl-30409775

ABSTRACT

OBJECTIVE: Use of palliative care in hospitals for people at end of life varies. We examined rate and time of in-hospital palliative care use and associated interhospital variations. METHODS: We used admissions from all hospitals in New South Wales, Australia, within a 12-month period, for a cohort of adults who died in 73 public acute care hospitals between July 2010 and June 2014. Receiving palliative care and its timing were based on recorded use. RESULTS: Among 90 696 adults who died, 27% received palliative care, and the care was initiated 7.6 days (mean; SD: 3.3 days) before death. Over the 5-year period, the palliative care rate rose by 58%, varying extent across chronic conditions. The duration of palliative care before death declined by 7%. Patient (demographics, morbidities and service use) and hospital factors (size, location and availability of palliative care unit) explained half of the interhospital variation in outcomes: adjusted IQR in rate and duration of palliative care among hospitals were 23%-39% and 5.2-8.7 days, respectively. Hospitals with higher rates often initiated palliative care earlier (correlation: 0.39; p<0.01). CONCLUSION: Despite an increase over time in the palliative care rate, its initiation was late and of brief duration. Palliative care use was associated with patient and hospital characteristics; however, half of the between hospital variation remained unexplained. The observed suboptimal practices and variability indicate the need for expanded and standardised use of palliative care supported by assessment tools, service enhancement and protocols.


Subject(s)
Facilities and Services Utilization/statistics & numerical data , Hospice and Palliative Care Nursing/statistics & numerical data , Inpatients/statistics & numerical data , Palliative Care/statistics & numerical data , Patient Acceptance of Health Care/statistics & numerical data , Adult , Aged , Aged, 80 and over , Australia , Chronic Disease/therapy , Female , Hospitalization , Hospitals , Humans , Male , Middle Aged , New South Wales , Retrospective Studies , Terminal Care , Time Factors
5.
Anesth Analg ; 129(4): 1087-1092, 2019 10.
Article in English | MEDLINE | ID: mdl-30286008

ABSTRACT

BACKGROUND: Liver transplantation in children is often associated with coagulopathy and significant blood loss. Available data are limited. In this observational retrospective study, we assessed transfusion practices in pediatric patients undergoing liver transplantation at a single institution over the course of 9 years. METHODS: Data were retrospectively collected from patient medical records at the Children's Hospital of Pittsburgh of University of Pittsburgh Medical Center. All patients who underwent liver transplantation from January 2008 to June 2017 were included. Primary and secondary outcomes were volume of red blood cells (RBCs) transfused and mortality, respectively. RESULTS: From January 2008 to June 2017, there were 278 liver transplants in 271 patients. The number of primary transplants were 259, second retransplants 15, and third retransplants 4. Average age at transplantation was 6.9 years. Biliary atresia, maple syrup urine disease, urea cycle defect, and liver tumor were the leading indications accounting for 66 (23.7%), 45 (16.2%), 24 (8.6%), and 23 (8.3%) of transplants, respectively. Seventy-six cases (27.3%) did not require RBC transfusions. Among those transfused, 181 (89.6%) of the cases required <1 blood volume (BV). The median BV transfused among all cases was 0.21 (range, 0-9; Q1, 0; Q3, 0.45). There is a trend toward higher volume transfusions among infants (median, 0.46 BV) compared to children >12 months of age (0.12 BV). By diagnosis, the group requiring the highest median volume transfusion was patients with total parenteral nutrition-related liver failure (3.41 BV) followed by patients undergoing repeat transplants (0.6 BV). Comparison of primary versus repeat transplants shows a trend toward higher volume transfusions in third transplants (median, 2.71 BV), compared to second transplants (0.43 BV) and primary transplants (0.18 BV). Four of 271 patients (1.5%) died during admission involving liver transplantation. Nine of 271 patients (3.3%) died subsequently. Total mortality was 4.8%. CONCLUSIONS: In contrast to historically reported trends, evaluation of current transfusion practices reveals that most patients undergoing liver transplantation receive <1 BV of packed RBCs. More than 1 in 4 transplantations require no transfusion at all. Risk factors for greater transfusion need include younger age, total parenteral nutrition-related liver failure, and repeat transplantation.


Subject(s)
Erythrocyte Transfusion/trends , Liver Transplantation/trends , Practice Patterns, Physicians'/trends , Adolescent , Age Factors , Child , Child, Preschool , Erythrocyte Transfusion/adverse effects , Erythrocyte Transfusion/mortality , Female , Hospital Mortality/trends , Hospitals, Pediatric/trends , Humans , Infant , Liver Transplantation/adverse effects , Liver Transplantation/mortality , Male , Reoperation/trends , Retrospective Studies , Risk Assessment , Risk Factors , Time Factors , Treatment Outcome
6.
Intern Med J ; 49(4): 467-474, 2019 04.
Article in English | MEDLINE | ID: mdl-30043405

ABSTRACT

BACKGROUND: Place of death is an important indicator in palliative care, as out-of-hospital death is often preferred by patients and is less costly for the healthcare system. AIM: To examine variation and contributing factors in out-of-hospital death after receiving palliative care in hospital to inform improvement in transition of care between hospitals and communities. METHODS: Using hospital linked data (July 2010, June 2015) we followed individuals aged 50 or older who received palliative care in hospital and within 3 months to death who were last admitted to a public acute-care hospital in New South Wales, Australia (73 hospitals). RESULTS: Among 25 359 palliative care inpatients, 3677 (14%) died out of hospital. The out-of-hospital death rate was lower for younger patients, males and those living in the most deprived areas; it was higher for cancer patients and those who received palliative care before their last admission. Hospital size, location and availability of hospice care unit were not influential. Across hospitals, the median crude rate of out-of-hospital death was 14% (interquartile range 10-19%). The contributing factors explained 19% of the variation, resulting in a rate difference of 44% between hospitals with high versus low rates; 25% of hospitals had a higher and 14% had a lower than average adjusted out-of-hospital death rate. CONCLUSION: The majority of patients who received palliative care in hospital stayed in hospital until death. The variation in out-of-hospital death across hospitals was considerable and mostly remained unexplained. This variability warrants investigation into transition of palliative care between hospitals and communities to inform interventions.


Subject(s)
Chronic Disease/mortality , Death , Hospitals, Public/statistics & numerical data , Inpatients/statistics & numerical data , Palliative Care/statistics & numerical data , Aged , Aged, 80 and over , Chronic Disease/therapy , Female , Hospital Mortality , Humans , Male , Middle Aged , Neoplasms/mortality , Neoplasms/therapy , New South Wales/epidemiology , Retrospective Studies
7.
Biomed Chromatogr ; 31(5)2017 May.
Article in English | MEDLINE | ID: mdl-27696449

ABSTRACT

This study was undertaken to quantify the residue levels and propose the dissipation kinetics of thiacloprid formulated as suspension concentrate in field-incurred Asian pears grown under two different open-field conditions. Samples were extracted with 20% distilled water in acetonitrile; partitioned with brine water and dichloromethane; and purified with a Florisil solid phase extraction cartridge. The analyte was identified with an LC ultraviolet detector, and field-incurred samples were confirmed using LC-MS/MS. The calibration curve was linear over the range 0.05-5.0 mg/L with a satisfactory coefficient of determination (R2 = 0.9994). The limits of detection and limits of quantification (LOQ) were 0.003 and 0.01 mg/kg, respectively. The recovery rate fortified to blank samples at LOQ, 10× LOQ, and the maximum residue limit (MRL) were between 73.7 and 86.2% with relative standard deviation ≤9.0%. The residual concentrations at both sites were considerably lower than the MRL (0.7 mg/kg) set by the Korean Ministry of Food Drug Safety, with biological half-lives of 5.0 and 7.4 days, for sites 1 and 2, respectively. From the pre-harvest residue limit curve, it was predicted that if the residues were <1.13 or 1.40 mg/kg 10 days before harvest, the residue level would be lower than the MRL during harvest. Risk assessment on day 0 showed an acceptable daily intake (%) of 13.0% and 11.0% for sites 1 and site 2, respectively, which indicates that the residual amounts are not hazardous to the Korean population.


Subject(s)
Chromatography, Liquid/methods , Pesticide Residues/analysis , Pyridines/analysis , Pyrus/chemistry , Tandem Mass Spectrometry/methods , Thiazines/analysis , Calibration , Food Analysis/methods , Food Contamination/analysis , Kinetics , Limit of Detection , Neonicotinoids , Risk Assessment , Sensitivity and Specificity
8.
Biomed Chromatogr ; 31(6)2017 Jun.
Article in English | MEDLINE | ID: mdl-27859496

ABSTRACT

Solvent-free solid injection was applied to differentiate between wild and cultivated South Korean medicinal foods, including dureup (Aralia elata), deodeok (Codonopsis lanceolata) and doraji (Platycodon grandiflorus). A number of compounds were identified in wild and cultivated dureup (53 and 46), deodeok (47 and 51) and doraji (43 and 38). Secondary metabolites, including butanal,2-methyl-, ß-caryophyllene, neoclovene, α-humulene, γ-curcumene, ß-bisabolene, and phytol, were identified in dureup with significantly (P < 0.05) different amounts between both types. In deodeok, squalene and other main components such as acetic acid, methyl ester, furan-methyl-furfural, 2-furan-methanol, and 5-methyl-furfural, were statistically different between the two types. Doraji has significantly different compounds such as furfural, 5-methyl-furfural, 2-methoxy-phenol, 2-methoxy-4-(1-propenyl)-phenol, and 1-(4-hydroxy-3-methoxyphenyl)-2-propanone. Although we failed to confirm the key compounds, a new compound, namely desaspidinol, was synthesized for the first time and its retention index determined under the experimental conditions. This solventless, easy technique can be used as a simple way to discriminate between wild and cultivated types of medicinal plants via identification of volatile markers or specific fingerprints.


Subject(s)
Gas Chromatography-Mass Spectrometry/methods , Plants, Medicinal , Solvents/chemistry , Republic of Korea
9.
Br J Pharmacol ; 173(18): 2752-65, 2016 09.
Article in English | MEDLINE | ID: mdl-27423137

ABSTRACT

BACKGROUND AND PURPOSE: Diverse proteases cleave protease-activated receptor-2 (PAR2) on primary sensory neurons and epithelial cells to evoke pain and inflammation. Trypsin and tryptase activate PAR2 by a canonical mechanism that entails cleavage within the extracellular N-terminus revealing a tethered ligand that activates the cleaved receptor. Cathepsin-S and elastase are biased agonists that cleave PAR2 at different sites to activate distinct signalling pathways. Although PAR2 is a therapeutic target for inflammatory and painful diseases, the divergent mechanisms of proteolytic activation complicate the development of therapeutically useful antagonists. EXPERIMENTAL APPROACH: We investigated whether the PAR2 antagonist GB88 inhibits protease-evoked activation of nociceptors and protease-stimulated oedema and hyperalgesia in rodents. KEY RESULTS: Intraplantar injection of trypsin, cathespsin-S or elastase stimulated mechanical and thermal hyperalgesia and oedema in mice. Oral GB88 or par2 deletion inhibited the algesic and proinflammatory actions of all three proteases, but did not affect basal responses. GB88 also prevented pronociceptive and proinflammatory effects of the PAR2-selective agonists 2-furoyl-LIGRLO-NH2 and AC264613. GB88 did not affect capsaicin-evoked hyperalgesia or inflammation. Trypsin, cathepsin-S and elastase increased [Ca(2+) ]i in rat nociceptors, which expressed PAR2. GB88 inhibited this activation of nociceptors by all three proteases, but did not affect capsaicin-evoked activation of nociceptors or inhibit the catalytic activity of the three proteases. CONCLUSIONS AND IMPLICATIONS: GB88 inhibits the capacity of canonical and biased protease agonists of PAR2 to cause nociception and inflammation.


Subject(s)
Inflammation/metabolism , Nociceptors/metabolism , Oligopeptides/pharmacology , Receptor, PAR-2/agonists , Administration, Oral , Animals , Dose-Response Relationship, Drug , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Oligopeptides/administration & dosage , Rats , Rats, Sprague-Dawley , Receptor, PAR-2/deficiency , Receptor, PAR-2/metabolism , Structure-Activity Relationship
10.
Biomed Chromatogr ; 30(11): 1835-1842, 2016 Nov.
Article in English | MEDLINE | ID: mdl-27187504

ABSTRACT

Lepimectin, as an emulsifiable concentrate, was sprayed on shallots at the recommended dose rate (10 mL/20 L) to determine its residue levels, dissipation pattern, pre-harvest residue limits (PHRLs), and health risk. Samples were randomly collected over 10 days, extracted with acetonitrile, purified using an amino solid-phase extraction (NH2 -SPE) cartridge and analyzed using a high-performance liquid chromatography-photodiode array detection method. Field-incurred samples were confirmed using ultra-performance liquid chromatography-tandem mass spectrometry. The linearity was excellent, with a determination coefficient (R2 ) of ≥0.9991. The recoveries at two spiking levels (0.2 and 1.0 mg/kg) ranged from 84.49 to 87.64% with relative standard deviations of ≤7.04%. The developed method was applied to field samples grown in separate greenhouses, one located in Naju and one in Muan, in the Republic of Korea. The dissipation pattern was described by first-order kinetics with half-lives of 1.9 (Naju) and 1.7 days (Muan). The PHRL curves indicated that, if the lepimectin residues are <0.18 (Naju) and <0.13 mg/kg (Muan) 5 days before harvest, the residue levels will be lower than the maximum residue limit (0.05 mg/kg) upon harvesting. The risk assessment data indicated that lepimectin is safe for use in the cultivation of shallots, with no risk of detrimental effects to the consumer.


Subject(s)
Chromatography, High Pressure Liquid/methods , Food Additives/analysis , Lactones/analysis , Macrocyclic Compounds/analysis , Pesticide Residues/analysis , Shallots/chemistry , Tandem Mass Spectrometry/methods , Food Analysis/methods , Limit of Detection
11.
Biomed Chromatogr ; 30(10): 1535-40, 2016 Oct.
Article in English | MEDLINE | ID: mdl-26991987

ABSTRACT

The present study was carried out to develop an analytical method for the detection and quantification of bistrifluron, a benzoylphenylurea compound, in pear using high-performance liquid chromatography with UV detection. Samples were extracted using conventional, AOAC and EN quick, easy, cheap, effective, rugged and safe 'QuEChERS' methods. As expected, conventional and EN-QuEChERS methods gave higher recoveries than AOAC. In addition, interference around the analyte retention time was observed in the conventional method. Thus, the EN-QuEChERS method was selected and validated by studying various parameters, including linearity, limit of detection, limit of quantification (LOQ), recovery and precision. Linearity was excellent, with a correlation coefficient of 0.9998. Recovery rates at three spiking levels (0.05, 0.2 and 1 mg/kg) ranged from 73.76 to 98.66%. Intra- and inter-day precisions, expressed as relative standard deviations, were <6%. The LOQ of 0.05 mg/kg was considerably lower than the maximum residue limit (1 mg/kg) set by the Korean Ministry of Food and Drug Safety. The developed method was successfully applied to open-field pear samples, in which the target analyte was slowly dissipated (55% decline) over 14 days with a half-life of 10.19 days. Notably, the residue levels throughout the period of sample collection (14 days) were lower than the maximum residue limit, indicating that the residue was not hazardous for consumers. Copyright © 2016 John Wiley & Sons, Ltd.


Subject(s)
Chromatography, High Pressure Liquid/methods , Hydrocarbons, Halogenated/isolation & purification , Pesticide Residues/isolation & purification , Phenylurea Compounds/isolation & purification , Pyrus/chemistry , Hydrocarbons, Halogenated/analysis , Limit of Detection , Pesticide Residues/analysis , Phenylurea Compounds/analysis , Reproducibility of Results
12.
Environ Monit Assess ; 188(3): 144, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26846294

ABSTRACT

The degradation behavior of flonicamid and its metabolites (4-trifluoromethylnicotinic acid (TFNA) and N-(4-trifluoromethylnicotinoyl) glycine (TFNG)) was evaluated in red bell pepper over a period of 90 days under glass house conditions, including high temperature, low and high humidity, and in a vinyl house covered with high density polyethylene light shade covering film (35 and 75%). Flonicamid (10% active ingredient) was applied (via foliar application) to all fruits, including those groups grown under normal conditions (glass house) or under no shade cover (vinyl house). Samples were extracted using a Quick, Easy, Cheap, Effective, Rugged, and Safe "QuEChERS" method and analyzed using liquid chromatography-tandem mass spectrometry (LC/MS/MS). The method performance, including linearity, recovery, limits of detection (LOD), and quantitation (LOQ), was satisfactory. Throughout the experimental period, the residual levels of flonicamid and TFNG were not uniform, whereas that of TFNA remained constant. The total sum of the residues (flonicamid and its metabolites) was higher in the vinyl house with shade cover than in the glass house, under various conditions. The total residues were significantly higher when the treatment was applied under high light shade (75%). The flonicamid half-life decreased from 47.2 days (under normal conditions) to 28.4 days (at high temperatures) in the glass house, while it increased from 47.9 days (no shade cover) to 66 days (75% light shading) in the vinyl house. High humidity leads to decreases in the total sum of flonicamid residues in red bell pepper grown in a glass house, because it leads to an increase in the rate of water loss, which in turn accelerates the volatilization of the pesticide. For safety reasons, it is advisable to grow red bell pepper under glass house conditions because of the effects of solar radiation, which increases the rate of flonicamid degradation into its metabolites.


Subject(s)
Capsicum/chemistry , Niacinamide/analogs & derivatives , Pesticides/analysis , Chromatography, Liquid , Climate , Environmental Monitoring , Fruit/chemistry , Half-Life , Limit of Detection , Niacinamide/analysis , Sunlight , Tandem Mass Spectrometry/methods
13.
Neurogastroenterol Motil ; 27(11): 1675-80, 2015 Nov.
Article in English | MEDLINE | ID: mdl-26303377

ABSTRACT

BACKGROUND: Proteases play a major role in inflammatory diseases of the gastrointestinal tract. Activatable probes are a major technological advance, enabling sensitive detection of active proteases in tissue samples. Our aim was to synthesize an activatable probe for cathepsin S and validate its use in a mouse model of colitis. METHODS: We designed and synthesized a new fluorescent activatable probe, NB200, for the detection of active cathepsin S. Colitis was induced in C57BL/6 mice by the administration of 3% dextran sulfate sodium (DSS). Homogenized mouse colons, with or without the addition of the specific cathepsin S inhibitor MV026031, were incubated with NB200 in a fluorescent plate reader. KEY RESULTS: NB200 selectively detected purified cathepsin S and not other common inflammatory proteases. Homogenates of colon from mice with DSS colitis induced a significant fluorescent increase when compared to control animals (control vs DSS: p < 0.05 at 200 min and p < 0.01 at 220-240 min), indicating cathepsin S activation. The cathepsin S inhibitor abolished this increase in fluorescence (DSS vs DSS + MV026031: p < 0.05 at 140 min, p < 0.01 at 180 min, p < 0.001 at 200-240 min), which confirms cathepsin S activation. Cathepsin S activity correlated with the disease activity index (Spearman r = 0.77, p = 0.017). CONCLUSIONS & INFERENCES: Our investigation has demonstrated the utility of activatable probes for detecting protease activity in intestinal inflammation. Panels of such probes may allow 'signature' protease profiles to be established for a range of inflammatory diseases and disorders.


Subject(s)
Cathepsins/analysis , Colitis/enzymology , Fluorescent Dyes/chemical synthesis , Fluorescent Dyes/pharmacology , Animals , Colitis/chemically induced , Dextran Sulfate/toxicity , Disease Models, Animal , Mice , Mice, Inbred C57BL
14.
Genet Mol Res ; 14(3): 7727-39, 2015 Jul 13.
Article in English | MEDLINE | ID: mdl-26214454

ABSTRACT

Pinus krempfii Lecomte (Pinaceae) is an endemic tree to Vietnam with restricted habitats at higher altitudes in the highlands. In this study, genetic variation of four populations of P. krempfii was assessed using 17 microsatellite markers (single sequence repeats). Of these 17 markers, eight were polymorphic, and among the 42 putative alleles amplified, 32 were polymorphic (accounting for 76.19%). The Cong Troi population was found to be the most genetically diverse (Shannon's information index, I = 0.415, and percentage of polymorphic bands, PPB = 52.95%), whereas the Hon Giao population was found to have the lowest diversity (I = 0.330 and PPB = 47.06%). The genetic diversity at species level was also estimated (I = 0.414, PPB = 76.19%). Molecular variance was found to be low among populations (11.94%) and high among individuals within the populations (88.06%). Private alleles were not detected in the Hon Giao population. The Yang Ly population had a positive FIS (inbreeding coefficient) value of 0.071, while the three remaining populations had negative values (-0.116 for Cong Troi, -0.316 for Chu Yang Sin, and -0.350 for Hon Giao). The results obtained show an excess of homozygosity in the Yang Ly population, and also suggest a deficiency of heterozygosity for this population. Several approaches and measures of conservation for P. krempfii are discussed and proposed.


Subject(s)
Genetic Variation , Microsatellite Repeats/genetics , Pinus/genetics , Plant Leaves/genetics , Alleles , Genetic Loci , Geography , Haplotypes/genetics , Phylogeny , Polymorphism, Genetic , Vietnam
15.
Br J Pharmacol ; 171(16): 3881-94, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24779362

ABSTRACT

BACKGROUND AND PURPOSE: Protease-activated receptor 2 (PAR2) is expressed on nociceptive neurons, and can sensitize transient receptor potential (TRP) ion channels to amplify neurogenic inflammation and pain. The mechanisms by which this occurs are not fully understood. PAR2 causes receptor-operated activation of TRPV4 channels and TRPV4 null mice have attenuated PAR2-stimulated neurogenic inflammation and mechanical hyperalgesia. Here we investigate the intracellular signalling mechanisms underlying PAR2-induced TRPV4 channel activation and pain. EXPERIMENTAL APPROACH: Responses of non-transfected and TRPV4-transfected HEK293 cells to agonists of PAR2 (trypsin and SLIGRL) and TRPV4 channels (GSK1016790A) were determined using calcium imaging. Inhibitors of TRPV4 channels (HC067047), sarcoendoplasmic reticulum calcium transport ATPase (thapsigargin), Gαq (UBO-QIC), tyrosine kinases (bafetinib and dasatinib) or PI3 kinases (wortmannin and LY294002) were used to investigate signalling mechanisms. In vivo effects of tyrosine kinase inhibitors on PAR2 -induced mechanical hyperalgesia were assessed in mice. KEY RESULTS: In non-transfected HEK293 cells, PAR2 activation transiently increased intracellular calcium ([Ca(2+) ]i ). Functional expression of TRPV4 channels caused a sustained increase of [Ca(2+) ]i , inhibited by HC067047, bafetinib and wortmannin; but not by thapsigargin, UBO-QIC, dasatinib or LY294002. Bafetinib but not dasatinib inhibited PAR2-induced mechanical hyperalgesia in vivo. CONCLUSIONS AND IMPLICATIONS: This study supports a role for tyrosine kinases in PAR2-mediated receptor-operated gating of TRPV4 channels, independent of Gαq stimulation. The ability of a tyrosine kinase inhibitor to diminish PAR2-induced activation of TRPV4 channels and consequent mechanical hyperalgesia identifies bafetinib (which is in development in oncology) as a potential novel analgesic therapy.


Subject(s)
Hyperalgesia/metabolism , Pain/metabolism , Protein Kinase Inhibitors/pharmacology , Pyrimidines/pharmacology , Receptor, PAR-2/antagonists & inhibitors , TRPV Cation Channels/antagonists & inhibitors , Animals , HEK293 Cells , Humans , Leucine/analogs & derivatives , Leucine/pharmacology , Male , Mice, Inbred C57BL , Morpholines/pharmacology , Oligopeptides/pharmacology , Pyrroles/pharmacology , Receptor, PAR-2/agonists , Receptor, PAR-2/metabolism , Sulfonamides/pharmacology , TRPV Cation Channels/agonists , TRPV Cation Channels/genetics , TRPV Cation Channels/metabolism , Trypsin/pharmacology
16.
Br J Pharmacol ; 171(5): 1156-66, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24111923

ABSTRACT

Bile acids (BAs) are digestive secretions that are necessary for the emulsification and absorption of dietary fats. Given the episodic nature of BA secretion and intestinal re-absorption, the circulating and tissue levels of BAs, like those of the gut hormones, fluctuate in fasting and fed states, and BA levels and forms are markedly affected by disease. BAs exert widespread hormonal-like effects by activating receptors in the nucleus and at the plasma membrane. The nuclear steroid receptors mediate the genomic actions of BAs on BA, glucose and lipid homeostasis. GPBA (TGR5) is a G-protein coupled plasma membrane receptor for BAs that mediates many of the rapid, non-genomic actions of BAs. GPBA has been implicated in the control of glucose homeostasis, inflammation and liver functions. Recent observations have revealed an unexpected role for GPBA in the nervous system. GPBA is expressed by enteric neurons and enterochromaffin cells that control peristalsis, and GPBA mediates the prokinetic actions of BAs in the colon that have been known for millennia. GPBA is also present on primary spinal afferent and spinal neurons that are necessary for sensory transduction. BA-induced activation of GPBA in the sensory nervous system promotes scratching behaviours and analgesia, which may contribute to the pruritus and painless jaundice that are observed in some patients with chronic cholestatic disease, where circulating BA concentrations are markedly increased. Thus, GPBA has emerged as an intriguing target for diverse metabolic, inflammatory, digestive and sensory disorders, where agonists and antagonists may be of value.


Subject(s)
Bile Acids and Salts/metabolism , Receptors, G-Protein-Coupled/metabolism , Animals , Gastrointestinal Diseases/metabolism , Glucose/metabolism , Humans , Liver Diseases/metabolism , Neurotransmitter Agents/metabolism , Receptors, G-Protein-Coupled/agonists , Sensation Disorders/metabolism
17.
Proc Natl Acad Sci U S A ; 109(43): E2939-48, 2012 Oct 23.
Article in English | MEDLINE | ID: mdl-23019585

ABSTRACT

Chemoresistance to platinum therapy is a major obstacle that needs to be overcome in the treatment of ovarian cancer patients. The high rates and patterns of therapeutic failure seen in patients are consistent with a steady accumulation of drug-resistant cancer stem cells (CSCs). This study demonstrates that the Notch signaling pathway and Notch3 in particular are critical for the regulation of CSCs and tumor resistance to platinum. We show that Notch3 overexpression in tumor cells results in expansion of CSCs and increased platinum chemoresistance. In contrast, γ-secretase inhibitor (GSI), a Notch pathway inhibitor, depletes CSCs and increases tumor sensitivity to platinum. Similarly, a Notch3 siRNA knockdown increases the response to platinum therapy, further demonstrating that modulation of tumor chemosensitivity by GSI is Notch specific. Most importantly, the cisplatin/GSI combination is the only treatment that effectively eliminates both CSCs and the bulk of tumor cells, indicating that a dual combination targeting both populations is needed for tumor eradication. In addition, we found that the cisplatin/GSI combination therapy has a synergistic cytotoxic effect in Notch-dependent tumor cells by enhancing the DNA-damage response, G(2)/M cell-cycle arrest, and apoptosis. Based on these results, we conclude that targeting the Notch pathway could significantly increase tumor sensitivity to platinum therapy. Our study suggests important clinical applications for targeting Notch as part of novel treatment strategies upon diagnosis of ovarian cancer and at recurrence. Both platinum-resistant and platinum-sensitive relapses may benefit from such an approach as clinical data suggest that all relapses after platinum therapy are increasingly platinum resistant.


Subject(s)
Antineoplastic Agents/therapeutic use , Cisplatin/therapeutic use , Neoplastic Stem Cells/pathology , Ovarian Neoplasms/pathology , Receptors, Notch/metabolism , Animals , Cell Cycle , Cell Death , DNA Damage , Drug Resistance, Neoplasm , Female , Humans , Mice , Ovarian Neoplasms/drug therapy , Receptor, Notch3 , Xenograft Model Antitumor Assays
18.
Oncogene ; 31(24): 2953-67, 2012 Jun 14.
Article in English | MEDLINE | ID: mdl-21986942

ABSTRACT

The epidermal growth factor receptor (EGFR) is essential to multiple physiological and neoplastic processes via signaling by its tyrosine kinase domain and subsequent activation of transcription factors. EGFR overexpression and alteration, including point mutations and structural variants, contribute to oncogenesis in many tumor types. In this study, we identified an in-frame splice variant of the EGFR called mini-LEEK (mLEEK) that is more broadly expressed than the EGFR and is overexpressed in several cancers. Unlike previously characterized EGFR variants, mLEEK lacks the extracytoplasmic, transmembrane and tyrosine kinase domains. mLEEK localizes in the nucleus and functions as a transcription factor to regulate target genes involved in the cellular response to endoplasmic reticulum (ER) stress, including the master regulator of the unfolded protein response (UPR) pathways, molecular chaperone GRP78/Bip. We demonstrated that mLEEK regulates GRP78 transcription through direct interaction with a cis-regulatory element within the gene promoter. Several UPR pathways were interrogated and mLEEK expression was found to attenuate the induction of all pathways upon ER stress. Conversely, knockdown of mLEEK resulted in caspase-mediated cell death and sensitization to ER stress. These findings indicate that mLEEK levels determine cellular responses to unfavorable conditions that cause ER stress. This information, along with the overexpression of mLEEK in tumors, suggests unique strategies for therapeutic intervention. Furthermore, the identification of mLEEK expands the known mechanisms by which the EGFR gene contributes to oncogenesis and represents the first link between two previously disparate areas in cancer cell biology: EGFR signaling and the UPR.


Subject(s)
ErbB Receptors/biosynthesis , Gene Expression Regulation, Neoplastic , Neoplasms/genetics , Transcription, Genetic , Transcriptional Activation , Adenocarcinoma/metabolism , Cell Line, Tumor , Cell Nucleus/metabolism , Endoplasmic Reticulum Chaperone BiP , Endoplasmic Reticulum Stress , ErbB Receptors/genetics , Female , Heat-Shock Proteins/biosynthesis , Heat-Shock Proteins/genetics , Humans , Lung/metabolism , Lung Neoplasms/genetics , Lung Neoplasms/metabolism , Melanoma/genetics , Melanoma/metabolism , Ovarian Neoplasms/metabolism , Ovary/metabolism , Promoter Regions, Genetic , Protein Isoforms/biosynthesis , Protein Isoforms/genetics , Protein Structure, Tertiary , Skin/metabolism , Skin Neoplasms/genetics , Skin Neoplasms/metabolism , Unfolded Protein Response
19.
Aust N Z J Obstet Gynaecol ; 52(1): 62-6, 2012 Feb.
Article in English | MEDLINE | ID: mdl-21923842

ABSTRACT

BACKGROUND: Over 2.6 million babies are stillborn every year mostly in low- and middle-income countries, where cause of death remains often unexplained. AIM: To determine the applicability and utility of the Perinatal Society of Australia and New Zealand (PSANZ) Clinical Practice Guideline (CPG) for Perinatal Mortality in reducing the proportion of unexplained stillbirths in a hospital setting in Vietnam. METHODS: An analytic cross-sectional study of stillborn babies born at a major maternity facility in Vietnam. Maternal history, external physical examination of the baby and placental macroscopic examination were performed. Two experienced classifiers independently assigned PSANZ perinatal death classification (PDC). This was compared to cause of death documented in the hospital records. RESULTS: 107 stillborn babies were born to 105 mothers. The proportion of stillborn babies classified as unexplained was reduced from 52.3 to 24.3% (P < 0.01) using the PSANZ-PDC system. Causes of death were congenital abnormalities (35.6%), hypertension (8.4%), fetal growth restriction (8.4%), specific perinatal conditions (8.4%), spontaneous preterm (6.5%), maternal conditions (5.6%) and antepartum haemorrhage (3.7%). CONCLUSIONS: Application of the PSANZ-CPG and stillbirth classification system is effective and feasible in a low-income country facility setting and resulted in a reduction in the number of babies classified as unexplained stillbirth in Vietnam.


Subject(s)
Cause of Death , Fetal Death/classification , Practice Guidelines as Topic , Pregnancy Complications/epidemiology , Stillbirth/epidemiology , Adult , Cross-Sectional Studies , Developing Countries , Female , Humans , Middle Aged , Pregnancy , Urban Population , Vietnam/epidemiology , Young Adult
20.
Int J Gynaecol Obstet ; 116(1): 22-5, 2012 Jan.
Article in English | MEDLINE | ID: mdl-22088409

ABSTRACT

OBJECTIVE: To assess the use of fetal foot length for predicting gestational age in stillborn fetuses in Vietnam and the ability of this measurement to differentiate early from late fetal deaths. METHODS: In a prospective case series, gestational age was determined from either certain first day of last menstrual period or early ultrasound scan. Foot length was measured, with a non-elastic tape measure, from the heel to the tip of the longest toe. Agreement of observed and predicted foot length for gestational age was tested, as well as the influence of fetal characteristics. RESULTS: Accurate gestational age and foot length were available for 52 of 107 participants. Strong agreement was demonstrated between observed and predicted values of foot length across gestations (95% confidence interval, -4.7 to 4.3 weeks). Accuracy of fetal foot length in predicting gestational age was affected by growth restriction but not fetal gender, maceration, or congenital anomalies. Fetal foot length of 55 mm or greater demonstrated a sensitivity and specificity of 88% in identifying late fetal deaths. CONCLUSION: Foot length is a good differentiator of early and late fetal death, which is important for the global recording of the number of stillbirths.


Subject(s)
Foot/pathology , Gestational Age , Stillbirth , Adult , Cross-Sectional Studies , Female , Humans , Predictive Value of Tests , Pregnancy , Prospective Studies , Sensitivity and Specificity , Vietnam
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