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1.
J Mol Cell Cardiol ; 189: 52-65, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38346641

RESUMO

Adipocytes normally accumulate in the epicardial and pericardial layers around the human heart, but their infiltration into the myocardium can be proarrhythmic. METHODS AND RESULTS: Human adipose derived stem/stromal cells and human induced pluripotent stem cells (hiPSC) were differentiated, respectively into predominantly white fat-like adipocytes (hAdip) and ventricular cardiomyocytes (CMs). Adipocytes cultured in CM maintenance medium (CM medium) maintained their morphology, continued to express adipogenic markers, and retained clusters of intracellular lipid droplets. In contrast, hiPSC-CMs cultivated in adipogenic growth medium displayed abnormal cell morphologies and more clustering across the monolayer. Pre-plated hiPSC-CMs co-cultured in direct contact with hAdips in CM medium displayed prolonged action potential durations, increased triangulation, slowed conduction velocity, increased conduction velocity heterogeneity, and prolonged calcium transients. When hAdip-conditioned medium was added to monolayer cultures of hiPSC-CMs, results similar to those recorded with direct co-cultures were observed. Both co-culture and conditioned medium experiments resulted in increases in transcript abundance of SCN10A, CACNA1C, SLC8A1, and RYR2, with a decrease in KCNJ2. Human adipokine immunoblots revealed the presence of cytokines that were elevated in adipocyte-conditioned medium, including MCP-1, IL-6, IL-8 and CFD that could induce electrophysiological changes in cultured hiPSC-CMs. CONCLUSIONS: Co-culture of hiPSC-CMs with hAdips reveals a potentially pathogenic role of infiltrating human adipocytes on myocardial tissue. In the absence of structural changes, hAdip paracrine release alone is sufficient to cause CM electrophysiological dysfunction mirroring the co-culture conditions. These effects, mediated largely by paracrine mechanisms, could promote arrhythmias in the heart.


Assuntos
Células-Tronco Pluripotentes Induzidas , Miócitos Cardíacos , Humanos , Células Cultivadas , Meios de Cultivo Condicionados/farmacologia , Diferenciação Celular/fisiologia , Adipócitos , Potenciais de Ação
2.
Am J Gastroenterol ; 119(2): 331-341, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-37782524

RESUMO

INTRODUCTION: Gastric emptying testing (GET) assesses gastric motility, however, is nonspecific and insensitive for neuromuscular disorders. Gastric Alimetry (GA) is a new medical device combining noninvasive gastric electrophysiological mapping and validated symptom profiling. This study assessed patient-specific phenotyping using GA compared with GET. METHODS: Patients with chronic gastroduodenal symptoms underwent simultaneous GET and GA, comprising a 30-minute baseline, 99m TC-labelled egg meal, and 4-hour postprandial recording. Results were referenced to normative ranges. Symptoms were profiled in the validated GA App and phenotyped using rule-based criteria based on their relationships to the meal and gastric activity: (i) sensorimotor, (ii) continuous, and (iii) other. RESULTS: Seventy-five patients were assessed, 77% female. Motility abnormality detection rates were as follows: GET 22.7% (14 delayed, 3 rapid), GA spectral analysis 33.3% (14 low rhythm stability/low amplitude, 5 high amplitude, and 6 abnormal frequency), and combined yield 42.7%. In patients with normal spectral analysis, GA symptom phenotypes included sensorimotor 17% (where symptoms strongly paired with gastric amplitude, median r = 0.61), continuous 30%, and other 53%. GA phenotypes showed superior correlations with Gastroparesis Cardinal Symptom Index, Patient Assessment of Upper Gastrointestinal Symptom Severity Index, and anxiety scales, whereas Rome IV Criteria did not correlate with psychometric scores ( P > 0.05). Delayed emptying was not predictive of specific GA phenotypes. DISCUSSION: GA improves patient phenotyping in chronic gastroduodenal disorders in the presence and absence of motility abnormalities with increased correlation with symptoms and psychometrics compared with gastric emptying status and Rome IV criteria. These findings have implications for the diagnostic profiling and personalized management of gastroduodenal disorders.


Assuntos
Duodenopatias , Gastroparesia , Humanos , Feminino , Masculino , Esvaziamento Gástrico/fisiologia , Gastroparesia/diagnóstico por imagem , Cintilografia
3.
Colorectal Dis ; 26(6): 1101-1113, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38698504

RESUMO

AIM: Prolonged postoperative ileus (PPOI) is common and is associated with a significant healthcare burden. Previous studies have attempted to predict PPOI clinically using risk prediction algorithms. The aim of this work was to systematically review and compare risk prediction algorithms for PPOI following colorectal surgery. METHOD: A systematic literature search was conducted using MEDLINE, Embase, Web of Science and CINAHL Plus. Studies that developed and/or validated a risk prediction algorithm for PPOI in adults following colorectal surgery were included. Data were collected on study design, population and operative characteristics, the definition of PPOI used and risk prediction algorithm design and performance. Quality appraisal was assessed using the PROBAST tool. RESULTS: Eleven studies with 87 549 participants were included in our review. Most were retrospective, single-centre analyses (6/11, 55%) and rates of PPOI varied from 10% to 28%. The most commonly used variables were sex (8/11, 73%), age (6/11, 55%) and surgical approach (5/11, 45%). Area under the curve ranged from 0.68-0.78, and only three models were validated. However, there was significant variation in the definition of PPOI used. No study reported sensitivity, specificity or positive/negative predictive values. CONCLUSION: Currently available risk prediction algorithms for PPOI appear to discriminate moderately well, although there is a lack of validation data. Future studies should aim to use a standardized definition of PPOI, comprehensively report model performance and validate their findings using internal and external methodologies.


Assuntos
Algoritmos , Íleus , Complicações Pós-Operatórias , Humanos , Íleus/etiologia , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/diagnóstico , Medição de Risco/métodos , Feminino , Masculino , Pessoa de Meia-Idade , Adulto , Idoso , Fatores de Risco , Cirurgia Colorretal/efeitos adversos , Estudos Retrospectivos , Fatores de Tempo
4.
Dig Dis Sci ; 2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38689198

RESUMO

BACKGROUND: Chronic nausea and vomiting syndromes (CNVS), gastroparesis and functional dyspepsia (FD) are complex disorders. Body Surface Gastric Mapping (BSGM), a new test of gastric function, using Gastric Alimetry® (Alimetry, New Zealand) may be useful for de-escalating healthcare utilisation. This study aimed to define healthcare costs and estimate health economic impacts of implementing this test in patients with chronic gastroduodenal symptoms. METHODS: Consecutive patients at a tertiary referral centre evaluated with Gastric Alimetry were included. Frequency and cost data relating to medical investigations, hospital and outpatient presentations were evaluated. Costs of healthcare utilisation were calculated, and the potential cost savings of implementing Gastric Alimetry within a diagnostic decision-tree model were estimated. RESULTS: Overall, 31 consecutive patients (mean age 36.1 years; 83.9% female; predominant symptoms: nausea [83.9%], pain [61.3%], vomiting [67.7%] and bloating [35.5%]) completed Gastric Alimetry testing. Repeat gastroscopy and abdominal CT rates were 29% (8/28) and 85% (11/13), respectively. Gastric Alimetry testing identified spectral abnormalities in 45.2% of patients, and symptom profiling classified a further 29.1% of patients. Median annualised cost difference after test introduction was NZ$-12,032. Estimated reductions in investigation-related costs when incorporating Gastric Alimetry into the diagnostic workflow model were approximately NZ$1,300 per patient. CONCLUSIONS: Healthcare utilisation and confirmatory testing rates remain high in nausea and vomiting syndromes. This study presents real-world data, together with a decision-tree analysis, showing Gastric Alimetry can streamline clinical care pathways, resulting in reduced healthcare utilisation and cost.

5.
Am J Gastroenterol ; 118(6): 1047-1057, 2023 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-36534985

RESUMO

INTRODUCTION: Body surface gastric mapping (BSGM) is a new noninvasive test of gastric function. BSGM offers several novel and improved biomarkers of gastric function capable of differentiating patients with overlapping symptom profiles. The aim of this study was to define normative reference intervals for BSGM spectral metrics in a population of healthy controls. METHODS: BSGM was performed in healthy controls using Gastric Alimetry (Alimetry, New Zealand) comprising a stretchable high-resolution array (8 × 8 electrodes; 196 cm 2 ), wearable Reader, and validated symptom-logging App. The evaluation encompassed a fasting baseline (30 minutes), 482 kCal meal, and 4-hour postprandial recording. Normative reference intervals were calculated for BSGM metrics including the Principal Gastric Frequency, Gastric Alimetry Rhythm Index (a measure of the concentration of power in the gastric frequency band over time), body mass index (BMI)-adjusted amplitude (µV), and fed:fasted amplitude ratio. Data were reported as median and reference interval (5th and/or 95th percentiles). RESULTS: A total of 110 subjects (55% female, median age 32 years [interquartile range 24-50], median BMI 23.8 kg/m 2 [interquartile range 21.4-26.9]) were included. The median Principal Gastric Frequency was 3.04 cycles per minute; reference interval: 2.65-3.35 cycles per minute. The median Gastric Alimetry Rhythm Index was 0.50; reference interval: ≥0.25. The median BMI-adjusted amplitude was 37.6 µV; reference interval: 20-70 µV. The median fed:fasted amplitude ratio was 1.85; reference interval ≥1.08. A higher BMI was associated with a shorter meal-response duration ( P = 0.014). DISCUSSION: This study provides normative reference intervals for BSGM spectral data to inform diagnostic interpretations of abnormal gastric function.


Assuntos
Jejum , Estômago , Humanos , Feminino , Adulto , Masculino , Valores de Referência , Estômago/diagnóstico por imagem , Índice de Massa Corporal , Período Pós-Prandial
6.
Br J Surg ; 110(9): 1197-1205, 2023 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-37303206

RESUMO

BACKGROUND: Epidemiological studies on acute aortic syndrome (AAS) have relied largely on unverified administrative coding, leading to wide-ranging estimates of incidence. This study aimed to evaluate the incidence, management, and outcomes of AAS in Aotearoa New Zealand. METHODS: This was a national population-based retrospective study of patients presenting with an index admission of AAS from 2010 to 2020. Cases from the Ministry of Health National Minimum Dataset, National Mortality Collection, and the Australasian Vascular Audit were cross-verified with hospital notes. Poisson regression adjusted for sex and age was used to investigate trends over time. RESULTS: During the study interval, 1295 patients presented to hospital with confirmed AAS, including 790 with type A (61.0 per cent) and 505 with type B (39.0 per cent) AAS. A total of 290 patients died out of hospital between 2010 and 2018. The overall incidence of aortic dissection including out-of-hospital cases was 3.13 (95 per cent c.i. 2.96 to 3.30) per 100 000 person-years, and this increased by an average of 3 (95 per cent c.i. 1 to 6) per cent per year after adjustment for age and sex adjustment on Poisson regression, driven by increasing type A cases. Age-standardized rates of disease were higher in men, and in Maori and Pacific populations. The management strategies used, and 30-day mortality rates among patients with type A (31.9 per cent) and B (9.7 per cent) disease have remained constant over time. CONCLUSION: Mortality after AAS remains high despite advances over the past decade. The disease incidence and burden are likely to continue to increase with an ageing population. There is impetus now for further work on disease prevention and the reduction of ethnic disparities.


Assuntos
Síndrome Aórtica Aguda , Humanos , Masculino , Síndrome Aórtica Aguda/epidemiologia , Incidência , Povo Maori , Morbidade , Estudos Retrospectivos , Nova Zelândia/epidemiologia , População das Ilhas do Pacífico
7.
Colorectal Dis ; 25(5): 861-871, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36587285

RESUMO

BACKGROUND: Readmissions after colorectal cancer surgery are common, despite advancements in surgical care, and have a significant impact on both individual patients and overall healthcare costs. The aim of this study was to determine the 30-and 90 days readmission rate after colorectal cancer surgery, and to investigate the risk factors and clinical reasons for unplanned readmissions. METHOD: A multicenter, population-based study including all patients discharged after index colorectal cancer resection from 2010 to 2020 in Aotearoa New Zealand (AoNZ) was completed. The Ministry of Health National Minimum Dataset was used. Rates of readmission at 30 days and 90 days were calculated. Mixed-effect logistic regression models were built to investigate factors associated with unplanned readmission. Reasons for readmission were described. RESULTS: Data were obtained on 16,885 patients. Unplanned 30-day and 90-day hospital readmission rates were 15.1% and 23.7% respectively. The main readmission risk factors were comorbidities, advanced disease, and postoperative complications. Hospital level variation was not present. Despite risk adjustment, R2 value of models was low (30 days: 4.3%, 90 days: 5.2%). The most common reasons for readmission were gastrointestinal causes (32.1%) and wound complications (14.4%). Rates of readmission did not improve over the 11 years study period (p = 0.876). CONCLUSION: Readmissions following colorectal resections in AoNZ are higher than other comparable healthcare systems and rates have remained constant over time. While patient comorbidities and postoperative complications are associated with readmission, the explanatory value of these variables is poor. To reduce unplanned readmissions, efforts should be focused on prevention and early detection of post-discharge complications.


Assuntos
Neoplasias Colorretais , Readmissão do Paciente , Humanos , Assistência ao Convalescente , Estudos Retrospectivos , Alta do Paciente , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/diagnóstico , Fatores de Risco , Neoplasias Colorretais/cirurgia , Neoplasias Colorretais/complicações
8.
J Vasc Surg ; 75(2): 455-463.e2, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34506891

RESUMO

BACKGROUND: Disparities in cardiovascular disease according to socioeconomic factors and ethnicity are a global issue. The indigenous Maori population of New Zealand is not exempt. The aims of the present study were to assess whether ethnic disparities exist in the presentation and outcomes of acute aortic syndrome (AAS), including aortic dissection, intramural hematoma, and penetrating aortic ulcer, in New Zealand. METHODS: A retrospective observational cohort study of consecutive AAS patients presenting to a tertiary referral center covering the Midland region of New Zealand (population, 816,900; 23.3% Maori) during a 10-year period was completed (2010-2020). Data were assessed by ethnicity (Maori vs non-Maori) and Stanford classification of AAS. The incidence of disease, 30-day mortality, and long-term all-cause and aortic-related mortality were recorded and assessed using logistic regression and Cox proportional hazards models. RESULTS: A total of 250 patients had presented with AAS (Maori, 92 [36.8%]; type A, 144 [57.6%]). The age-standardized rates of AAS were higher in Maori than in non-Maori patients (6.9/100,000 person-years vs 2.0/100,000 person-years; risk ratio, 3.56; 95% confidence interval, 1.50-8.53; P = .002). Maori patients had presented at a younger age for both type A (age, 54.4 ± 12 years vs 66.0 ± 13.2 years; P < .001) and type B (age, 61.3 ± 10.2 years vs 68.8 ± 13.7 years; P = .005) AAS. Mortality at 30 days was higher for those with type A than for those with type B AAS (33.3% vs 13.2%; P < .001) but did not differ by ethnicity in our cohort. On multivariate analysis, no differences were found in 30-day or long-term survival when stratified by ethnicity. CONCLUSIONS: The results from the present study have demonstrated that ethnic disparities in AAS exist in New Zealand, with Maori presenting at a younger age and with a greater incidence compared with other ethnicities. Whether this disparity is related to socioeconomic factors, access to preventive care, or other factors remains to be elucidated. Despite these differences in disease presentation, the survival outcomes when stratified by ethnicity were comparable in the present cohort.


Assuntos
Aneurisma da Aorta Abdominal/etnologia , Etnicidade , Medição de Risco/métodos , Doença Aguda , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Seguimentos , Humanos , Incidência , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Nova Zelândia/epidemiologia , Estudos Retrospectivos , Fatores Socioeconômicos , Taxa de Sobrevida/tendências , Síndrome , Adulto Jovem
9.
Br J Surg ; 109(2): 182-190, 2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-34907419

RESUMO

BACKGROUND: This review evaluated the utility of single quantitative faecal immunochemical test (FIT) as a triaging tool for patients with symptoms of possible colorectal cancer, the effect of symptoms on FIT accuracy, and the impact of triaging incorporating FIT on service provision. METHODS: Five databases were searched. Meta-analyses of the extracted FIT sensitivities and specificities for detection of colorectal cancer at reported f-Hb thresholds were performed. Secondary outcomes included sensitivity and specificity of FIT for advanced colorectal neoplasia and serious bowel disease. Subgroup analysis by FIT brand and symptoms was undertaken. RESULTS: Fifteen prospective cohort studies, including 28 832 symptomatic patients were included. At the most commonly reported f-Hb positivity threshold of ≥ 10 µg Hb/g faeces (n=13), the summary sensitivity was 88.7% (95% c.i. 85.2 to 91.4) and the specificity was 80.5% (95% c.i. 75.3 to 84.8) for colorectal cancer. At lower limits of detection of ≥ 2 µg Hb/g faeces, the summary sensitivity was 96.8% (95% c.i. 91.0 to 98.9) and the specificity was 65.6% (95% c.i. 59.0 to 71.6). At the upper f-Hb positivity thresholds of ≥ 100 µg Hb/g faeces and ≥ 150 µg Hb/g faeces, summary sensitivities were 68.1% (95% c.i. 59.2 to 75.9) and 66.3% (95% c.i. 52.2 to 78.0), with specificities of 93.4% (95% c.i. 91.3 to 95.1) and 95.1% (95% c.i. 93.6 to 96.3) respectively. FIT sensitivity was comparable between different assay brands. FIT sensitivity may be higher in patients reporting rectal bleeding. CONCLUSION: Single quantitative FIT at lower f-Hb positivity thresholds can adequately exclude colorectal cancer in symptomatic patients and provides a data-based approach to prioritization of colonoscopy resources.


Assuntos
Neoplasias Colorretais/diagnóstico , Detecção Precoce de Câncer/métodos , Imunoquímica , Sangue Oculto , Triagem/métodos , Fezes/química , Hemoglobinas/análise , Humanos
10.
Neuromodulation ; 23(8): 1144-1150, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33006195

RESUMO

OBJECTIVES: Transcutaneous electrical nerve stimulation (TENS) is a noninvasive analgesic neurostimulation modality. Difficulties in clinical trial blinding and therapy administration have limited conclusions of previous trials. The aims of this study were to first investigate the feasibility and acceptability of patient-administered TENS after surgery, and second, the feasibility of using sub-sensory TENS as a proxy sham group for patient-blinding. MATERIALS AND METHODS: Over a four-month period, patients undergoing laparoscopic cholecystectomy at a single center were randomized to receive maximally tolerable high-intensity (HI) TENS or sub-sensory low-intensity (LI) TENS. Patients and outcome assessors were blinded. Primary outcomes were the feasibility, tolerability, and acceptability of patient self-administered TENS, measured by patient-reported outcomes, and the strength of patient-blinding, measured using the James Blinding Index (JBI). Secondary outcomes explored clinical recovery and analgesic efficacy. RESULTS: Nineteen patients were screened for inclusion; ten patients were randomized and completed the feasibility study. TENS therapy was variably utilized (median duration of TENS 5.3 hours/day [IQR: 4.1-6.9]). The JBI was 0.7, indicating a strong strength of blinding. Majority of patients found the TENS unit easy to use (90%) and were confident with self-administration (100%). No patients experienced adverse effects of TENS use. CONCLUSIONS: Patient-administered TENS is safe and acceptable. Future studies may use sub-sensory TENS as a proxy sham control to more reliably blind patients. A larger, double-blinded RCT employing these techniques is now needed to determine the analgesic efficacy of TENS in an enhanced recovery setting, and its potential to reduce opiate usage.


Assuntos
Colecistectomia Laparoscópica , Dor Pós-Operatória , Estimulação Elétrica Nervosa Transcutânea , Analgésicos Opioides , Colecistectomia Laparoscópica/efeitos adversos , Estudos de Viabilidade , Humanos , Dor Pós-Operatória/etiologia , Dor Pós-Operatória/terapia , Autocuidado , Resultado do Tratamento
13.
Nanotechnology ; 28(11): 115709, 2017 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-28211360

RESUMO

In order to help reduce the agglomeration of TiO2 nanoparticles in polyurethane coatings while enhancing their photoactivity and mechanical/physical properties, this work examined encapsulating TiO2 nanoparticles in a thin layer of SiO2, prior to their nanocomposite polymerization. By applying a Stöber process, varying thicknesses of SiO2 were successfully coated onto the surface of anatase and rutile TiO2 nanoparticles. The methylene blue results showed that different loadings of SiO2 onto the TiO2 surface significantly influenced their photocatalytic activity. When the loading weight of SiO2 was lower than 3.25 wt%, the photocatalytic activity was enhanced, while with higher loadings, it gave lower photocatalytic activity. When the rutile phase TiO2 surface was fully covered with SiO2, an enhanced photocatalytic activity was observed. When these silica coated nanoparticles were applied in polyurethane coatings, increasing the amount of SiO2 on the titania surface increased the coatings contact angle from 75° to 87° for anatase phase and 70°-78° for rutile phase. The Young's modulus was also increased from 1.06 GPa to 2.77 GMPa for anatase phase and 1.06-2.17 GPa for rutile phase, attributed to the silica layer giving better integration. The thermal conductivity of the polyurethane coatings was also successfully decreased by encapsulating SiO2 on the titania surface for next generation high performance coatings.

16.
Transfusion ; 55(9): 2197-206, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25968419

RESUMO

BACKGROUND: Biochemical changes induced in red blood cells (RBCs) during storage may impair their function upon transfusion. Transfusion-associated stresses may further amplify storage lesion effects including increased phosphatidylserine (PS) exposure at the RBC membrane, microparticle (MP) release, and adhesion to endothelial cells (ECs). RBC stress susceptibility in vitro was investigated in relation to storage time and additive solution. STUDY DESIGN AND METHODS: Leukoreduced whole blood donations (n = 18) were paired, mixed, and resplit before separating the RBCs for storage in saline-adenine-glucose-mannitol (SAGM) or AS-1. Samples were taken after 3, 21, or 35 days. For oxidative stress treatment, RBCs were exposed to 0.5 mmol/L tert-butylhydroperoxide. Transfusion-associated stress was simulated by overnight culture at 37 °C with plasma containing inflammatory mediators. PS exposure and MPs were measured by flow cytometry and adhesion to ECs was tested under flow conditions. PS specificity of adhesion was tested by blocking with PS-containing lipid vesicles. RESULTS: Oxidative stress induced significantly higher PS exposure and adhesion to ECs in RBCs stored for 35 days compared to 3 days (p < 0.04). PS-containing vesicles blocked RBC-EC adhesion. After overnight culture with or without plasma, PS exposure and EC adhesion were significantly increased (p < 0.05). MP numbers increased with longer RBC storage and after RBC culture with plasma. Culture conditions influenced MP numbers from Day 35 RBCs. RBCs stored in SAGM had significantly higher PS exposure after stress treatment than AS-1 RBCs (p < 0.02). CONCLUSION: Storage for 35 days significantly increased RBC susceptibility to oxidative and in vitro transfusion-associated stresses and was higher for RBCs stored in SAGM compared to AS-1.


Assuntos
Adenina/farmacologia , Preservação de Sangue , Membrana Eritrocítica/metabolismo , Transfusão de Eritrócitos , Glucose/farmacologia , Manitol/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Cloreto de Sódio/farmacologia , Adesão Celular/efeitos dos fármacos , Técnicas de Cocultura , Células Endoteliais/metabolismo , Feminino , Humanos , Masculino , Soluções Farmacêuticas/farmacologia , Fosfatidilserinas/metabolismo , Fatores de Tempo
17.
Nanotechnology ; 26(31): 315702, 2015 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-26177824

RESUMO

The dispersion of light-absorbing inorganic nanomaterials in transparent plastics such as poly(ethylene-co-vinyl acetate) (PEVA) is of enormous current interest in emerging solar materials, including photovoltaic (PV) modules and commercial greenhouse films. Nanocrystalline semiconductor or quantum dots (QDs) have the potential to absorb UV light and selectively emit visible light, which can control plant growth in greenhouses or enhance PV panel efficiencies. This work provides a new and simple approach for loading mesoporous silica-encapsulated QDs into PEVA. Highly luminescent CdS and CdS-ZnS core-shell QDs with 5 nm size were synthesized using a modified facile approach based on pyrolysis of the single-molecule precursors and capping the CdS QDs with a thin layer of ZnS. To make both the bare and core-shell structure QDs more resistant against photochemical reactions, a mesoporous silica layer was grown on the QDs through a reverse microemulsion technique based on hydrophobic interactions. By careful experimental tuning, this encapsulation technique enhanced the quantum yield (∼65%) and photostability compared to the bare QDs. Both the encapsulated bare and core-shell QDs were then melt-mixed with EVA pellets using a mini twin-screw extruder and pressed into thin films with controlled thickness. The results demonstrated for the first time that mesoporous silica not only enhanced the quantum yield and photostability of the QDs but also improved the compatibility and dispersibility of QDs throughout the PEVA films. The novel light selective films show high visible light transmission (∼90%) and decreased UV transmission (∼75%).

18.
Planta Med ; 80(6): 509-16, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24687741

RESUMO

Extraction of medicinally active components from natural health products has become an emerging source for drug discovery. Of particular interest for this work was the finding and testing of a new ginsenoside from North American ginseng (Panax quinquefolius). In the present study, a large amount of 6″-O-acetylginsenoside Rb1, compound 7, was found using ultrasonic extraction of North American ginseng with DMSO aqueous solution. This new ginsenoside was well identified with MS, FTIR, and 1D (1H and 13C) and 2D (gCOSY, gHSQC, and gHMBC) NMR. Subsequent bioassay experiments confirmed that compound 7 demonstrated an additional immunosuppressive activity towards inhibiting the production of nitric oxide and tumor necrosis factor alpha in lipopolysaccharide-induced macrophage cells in a dose-dependent manner using murine macrophages. This new ginsenoside is encouraging for the further exploration and development of novel drugs.


Assuntos
Ginsenosídeos/uso terapêutico , Imunossupressores/uso terapêutico , Inflamação/tratamento farmacológico , Macrófagos/efeitos dos fármacos , Panax/química , Fitoterapia , Extratos Vegetais/uso terapêutico , Animais , Anti-Inflamatórios/isolamento & purificação , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Relação Dose-Resposta a Droga , Ginsenosídeos/química , Ginsenosídeos/isolamento & purificação , Ginsenosídeos/farmacologia , Imunossupressores/química , Imunossupressores/isolamento & purificação , Imunossupressores/farmacologia , Inflamação/induzido quimicamente , Inflamação/metabolismo , Lipopolissacarídeos , Macrófagos/metabolismo , Camundongos , Ácido Nítrico/metabolismo , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Fator de Necrose Tumoral alfa/metabolismo
19.
ANZ J Surg ; 94(5): 819-825, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38131414

RESUMO

BACKGROUND: Current guidelines for AAA management are based on landmark trials comparing EVAR and open aneurysm repair (OAR) conducted more than 20 years ago. Important advancements have been made in peri-operative care but the impact of EVAR and OAR on long-term patient survival has not been well reported using contemporary data. The objective of this study was to compare the short and long-term outcomes of OAR and EVAR in the recent era. METHODS: This retrospective observational study included all patients undergoing intact AAA repair in NZ from 1st of January 2011 until 31st of December 2019. Data was collected from national administrative and clinical vascular databases and matched using unique identifiers. Time-to-event survival analyses was conducted using cox proportional hazard models to adjust for confounders and propensity score matching were used. RESULTS: Two thousand two hundred and ninety-seven patients had an intact AAA repair with a median (IQR) age of 75 (69-80) years; 494 (21.2%) patients were females and 1206 (53%) underwent EVAR. The 30-day mortality for OAR and EVAR was 4.8% and 1.2%. The median (IQR) follow up was 5.2 (2.3-9.2) years. After propensity matching for co-variates, the study cohort consisted of 835 patients in each matched group. Patients undergoing EVAR had a higher overall mortality (HR 1.48 (95% CI: 1.26-1.74) after adjusting for confounders compared to OAR. CONCLUSION: Analysis of survival following EVAR and OAR in the current era demonstrates that patients that underwent EVAR had a lower 30-day mortality. However, in the long-term after adjusting for confounders OAR had a better overall survival.


Assuntos
Aneurisma da Aorta Abdominal , Correção Endovascular de Aneurisma , Pontuação de Propensão , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Aneurisma da Aorta Abdominal/cirurgia , Aneurisma da Aorta Abdominal/mortalidade , Nova Zelândia/epidemiologia , Estudos Retrospectivos , Taxa de Sobrevida , Fatores de Tempo , Resultado do Tratamento
20.
ANZ J Surg ; 2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38888264

RESUMO

BACKGROUND: Non-operative management of splenic injuries has significantly increased in the last decade with an increased emphasis on splenic preservation. This shift was assisted by increased availability of angioembolization, however, potential geographical variability in access exists in Aotearoa New Zealand (AoNZ). The aim of this study was to assess the management of splenic injury across AoNZ. METHOD: Five-year retrospective study of all patients admitted to AoNZ hospitals with blunt major trauma and a splenic injury. Patients were identified using the National Trauma Registry and cross-referenced with the National Minimum Data Set to determine their management. The primary outcome was the non-operative rate. RESULTS: Seven hundred seventy-three patients were included. Four hundred sixty-nine presented to a tertiary major trauma hospital and 304 to a secondary major trauma hospital. A difference was found in the rate of non-operative management between tertiary and secondary hospitals (P = 0.019). The rate of non-operative management was similar in mild (P = 0.814) and moderate (P = 0.825) injuries, however, significantly higher in severe injuries in tertiary hospitals (P = 0.009). No difference in mortality rate was found. CONCLUSION: This study found a difference in the management of splenic injuries between tertiary and secondary major trauma hospitals; predominantly due to a higher rate of operative management in patients with severe injuries at secondary hospitals. Despite this, no difference in mortality rate was found between tertiary and secondary hospitals.

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