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1.
Int J Biol Macromol ; 259(Pt 1): 129172, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38176496

RESUMO

Varieties of plant species may affect the composition and structures of the polysaccharides, thus have an impact on their chemical properties and biological activities. Herein, the present study comparatively evaluated the differences in the chemical composition, morphological structures, antioxidant activity, and anti-inflammatory activity of the stem and peel polysaccharides from different varieties of pitaya. The FT-IR and NMR spectra indicated that the six polysaccharides had similar structural features, whereas the physicochemical characterization showed that they differed significantly in terms of the monosaccharide composition, molecular weight, and surface morphology. In addition, different varieties of pitaya polysaccharides exhibited different antioxidant activities and similar anti-inflammatory activities. These data suggested that varietal differences resulted in pitaya stem and peel polysaccharides with different monosaccharide compositions and molecular weights, thus led to different antioxidant activities and protection against oxidative damage, while similar structural features were closely related to their similar anti-inflammatory activities. Therefore, the study of the stem and peel polysaccharides from different varieties of pitaya can help us to better understand the relationship between their composition and structure and their biological activities. In addition, pitaya stem and peel polysaccharides have the potential to act as antioxidants or to treat inflammatory damage.


Assuntos
Antioxidantes , Cactaceae , Antioxidantes/farmacologia , Antioxidantes/química , Espectroscopia de Infravermelho com Transformada de Fourier , Polissacarídeos/farmacologia , Polissacarídeos/química , Monossacarídeos , Anti-Inflamatórios/farmacologia
2.
J Am Soc Mass Spectrom ; 34(11): 2585-2593, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37870912

RESUMO

Extracellular vesicles (EVs) have emerged as a promising source of disease biomarkers for noninvasive early stage diagnoses, but a bottleneck in EV sample processing restricts their immense potential in clinical applications. Existing methods are limited by a low EV yield and integrity, slow processing speeds, low sample capacity, and poor recovery efficiency. We aimed to address these issues with a high-throughput automated workflow for EV isolation, EV lysis, protein extraction, and protein denaturation. The automation can process clinical urine samples in parallel, resulting in protein-covered beads ready for various analytical methods, including immunoassays, protein quantitation assays, and mass spectrometry. Compared to the standard manual lysis method for contamination levels, efficiency, and consistency of EV isolation, the automated protocol shows reproducible and robust proteomic quantitation with less than a 10% median coefficient of variation. When we applied the method to clinical samples, we identified a total 3,793 unique proteins and 40,380 unique peptides, with 992 significantly upregulated proteins in kidney cancer patients versus healthy controls. These upregulated proteins were found to be involved in several important kidney cancer metabolic pathways also identified with a manual control. This hands-free workflow represents a practical EV extraction and profiling approach that can benefit both clinical and research applications, streamlining biomarker discovery, tumor monitoring, and early cancer diagnoses.


Assuntos
Vesículas Extracelulares , Neoplasias Renais , Humanos , Fluxo de Trabalho , Proteômica/métodos , Proteínas/análise , Vesículas Extracelulares/química , Vesículas Extracelulares/metabolismo
3.
Expert Opin Drug Discov ; 18(12): 1367-1377, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37676052

RESUMO

INTRODUCTION: Computer-aided drug design (CADD) is a computational approach used to discover, develop, and analyze drugs and active molecules with similar biochemical properties. Molecular simulation technology has significantly accelerated drug research and reduced manufacturing costs. It is an optimized drug discovery method that greatly improves the efficiency of novel drug development processes. AREASCOVERED: This review discusses the development of molecular simulations of effective cancer inhibitors and traces the main outcomes of in silico studies by introducing representative categories of six important anticancer targets. The authors provide views on this topic from the perspective of both medicinal chemistry and artificial intelligence, indicating the major challenges and predicting trends. EXPERT OPINION: The goal of introducing CADD into cancer treatment is to realize a highly efficient, accurate, and desired approach with a high success rate for identifying potent drug candidates. However, the major challenge is the lack of a sophisticated data-filtering mechanism to verify bottom data from mixed-quality references. Consequently, despite the continuous development of algorithms, computer power, and interface optimization, specific data filtering mechanisms will become an urgent and crucial issue in the future.


Assuntos
Desenho Assistido por Computador , Neoplasias , Humanos , Inteligência Artificial , Desenho de Fármacos , Descoberta de Drogas/métodos , Neoplasias/tratamento farmacológico
4.
J Chromatogr A ; 1705: 464210, 2023 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-37451198

RESUMO

The residue of carbaryl in food is a threat to human health. In this study, activated soybean shell biochar (A-SBC) was used as a carrier, methacrylic acid (MAA) was used as a functional monomer, and carbaryl was used as a template molecule to synthesize the activated biochar surface molecularly imprinted polymer (A-SBC@MIP). The synthesized A-SBC@MIP was characterized by SEM, FT-IR, XRD and XPS techniques, and then applied as adsorbent for carbaryl removal. The adsorption capacity of A-SBC@MIP for carbaryl was 8.6 mg‧g-1 and the imprinting factor was 1.49 at the optimum ionic strength and pH. The kinetic and isothermal data indicated that it had fast mass transfer rate and high binding capacity(Qmax=47.9 mg‧g-1). A-SBC@MIP showed good regenerative properties and the adsorption of carbaryl was excellent in its structural analogues. A solid-phase extraction (SPE) column composed of A-SBC@MIP was developed for the detection of rice and corn under optimized conditions, with recoveries of 93-101% for the spiked carbaryl. The limit of detection (LOD) of the method was 3.6 µg‧kg-1 with good linearity (R2=0.994) in the range of 0.01-5.00 mg‧L-1. The results show that the developed MIPs-SPE can enrich carbaryl from food samples as a specific and cost-effective method.


Assuntos
Impressão Molecular , Oryza , Humanos , Carbaril , Polímeros Molecularmente Impressos , Impressão Molecular/métodos , Zea mays , Polímeros/química , Adsorção , Espectroscopia de Infravermelho com Transformada de Fourier , Extração em Fase Sólida/métodos
5.
Commun Med (Lond) ; 3(1): 64, 2023 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-37165152

RESUMO

BACKGROUND: Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene have been recognized as genetic risk factors for Parkinson's disease (PD). However, compared to cancer, fewer genetic mutations contribute to the cause of PD, propelling the search for protein biomarkers for early detection of the disease. METHODS: Utilizing 138 urine samples from four groups, healthy individuals (control), healthy individuals with G2019S mutation in the LRRK2 gene (non-manifesting carrier/NMC), PD individuals without G2019S mutation (idiopathic PD/iPD), and PD individuals with G2019S mutation (LRRK2 PD), we applied a proteomics strategy to determine potential diagnostic biomarkers for PD from urinary extracellular vesicles (EVs). RESULTS: After efficient isolation of urinary EVs through chemical affinity followed by mass spectrometric analyses of EV peptides and enriched phosphopeptides, we identify and quantify 4476 unique proteins and 2680 unique phosphoproteins. We detect multiple proteins and phosphoproteins elevated in PD EVs that are known to be involved in important PD pathways, in particular the autophagy pathway, as well as neuronal cell death, neuroinflammation, and formation of amyloid fibrils. We establish a panel of proteins and phosphoproteins as novel candidates for disease biomarkers and substantiate the biomarkers using machine learning, ROC, clinical correlation, and in-depth network analysis. Several putative disease biomarkers are further partially validated in patients with PD using parallel reaction monitoring (PRM) and immunoassay for targeted quantitation. CONCLUSIONS: These findings demonstrate a general strategy of utilizing biofluid EV proteome/phosphoproteome as an outstanding and non-invasive source for a wide range of disease exploration.


Parkinson's disease (PD) is a progressive neurological disorder that affects body movement because some brain cells stop producing the chemical dopamine. PD is often not diagnosed until it has advanced, making early detection crucial. To enable early detection, we investigated tiny packages called extracellular vesicles released from a variety of cells, including the brain cells, that can be found in urine as a potential source for diagnosing PD. These tiny packages contain different kinds of molecules from inside the cells. We analyzed urine samples from 138 individuals and found several proteins involved in PD development that could be biological indicators for early detection of the disease. We used various techniques to make sure that our findings were accurate. Our study suggests that looking at these proteins in urine could be a good way to detect PD in a non-invasive manner.

6.
Mol Cell Proteomics ; 22(5): 100536, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36997065

RESUMO

Translating the research capability and knowledge in cancer signaling into clinical settings has been slow and ineffective. Recently, extracellular vesicles (EVs) have emerged as a promising source for developing disease phosphoprotein markers to monitor disease status. This study focuses on the development of a robust data-independent acquisition (DIA) using mass spectrometry to profile urinary EV phosphoproteomics for renal cell cancer (RCC) grades differentiation. We examined gas-phase fractionated library, direct DIA (library-free), forbidden zones, and several different windowing schemes. After the development of a DIA mass spectrometry method for EV phosphoproteomics, we applied the strategy to identify and quantify urinary EV phosphoproteomes from 57 individuals representing low-grade clear cell RCC, high-grade clear cell RCC, chronic kidney disease, and healthy control individuals. Urinary EVs were efficiently isolated by functional magnetic beads, and EV phosphopeptides were subsequently enriched by PolyMAC. We quantified 2584 unique phosphosites and observed that multiple prominent cancer-related pathways, such as ErbB signaling, renal cell carcinoma, and regulation of actin cytoskeleton, were only upregulated in high-grade clear cell RCC. These results show that EV phosphoproteome analysis utilizing our optimized procedure of EV isolation, phosphopeptide enrichment, and DIA method provides a powerful tool for future clinical applications.


Assuntos
Carcinoma de Células Renais , Vesículas Extracelulares , Neoplasias Renais , Humanos , Carcinoma de Células Renais/metabolismo , Cromatografia de Afinidade/métodos , Transdução de Sinais , Neoplasias Renais/metabolismo , Vesículas Extracelulares/metabolismo
7.
Drug Dev Res ; 84(1): 110-120, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36433708

RESUMO

In this work, a series of indole-containing pyrazole-carbohydrazide derivatives A1-A25 were synthesized, and their biological activity on tubulin polymerization inhibition and mitotic catastrophe was evaluated. For introducing indole group to CA-4 pattern, the carbohydrazide linker was used for the first time. As the top hit, A18 suggested notable antiproliferation efficacy and tubulin polymerization inhibitory activity. Inferring comparable antitubulin effect with the positive control Colchicine, A18 indicated obviously lower cyto-toxicity. The cell scratch test showed that A18 could block the cell migration, while the confocal imaging depicted that A18 could induce the mitotic catastrophe via a Colchicine-like approach. The docking simulation visualized the probable binding pattern of A18. With the information in this work, some new hints on modification might be involved in further tubulin-related investigations.


Assuntos
Antineoplásicos , Moduladores de Tubulina , Moduladores de Tubulina/farmacologia , Moduladores de Tubulina/metabolismo , Tubulina (Proteína)/metabolismo , Linhagem Celular Tumoral , Simulação de Acoplamento Molecular , Antineoplásicos/farmacologia , Antineoplásicos/metabolismo , Colchicina/farmacologia , Indóis/farmacologia , Pirazóis/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Proliferação de Células , Relação Estrutura-Atividade
8.
Opt Express ; 30(8): 13238-13251, 2022 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-35472941

RESUMO

Structured illumination microscopy (SIM), a super-resolution technology, has a wide range of applications in life sciences. In this study, we present an electro-optic high-speed phase-shift super-resolution microscopy imaging system including 2D SIM, total internal reflection fluorescence-SIM, and 3D SIM modes. This system uses galvanometers and an electro-optic modulator to flexibly and quickly control the phase and direction of structured illumination patterns. Moreover, its design consists of precise timing for improved acquisition speed and software architecture for real-time reconstruction. The highest acquisition rate achieved was 151 frames/s, while the highest real-time super-resolution reconstruction frame rate achieved was over 25 frames/s.

9.
Int J Biol Macromol ; 193(Pt A): 378-386, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34699897

RESUMO

The merits of hyaluronic acid (HA) as a representative biological carbohydrate polymers especially in bioactivity and tailorability makes it ideal building block for the engineering of tissue engineering scaffolds. HA-based bio-composites integrate the characteristics of multi-component materials, possessing versatility and further improving the therapeutic efficacy. Human like collagen (HLC), which is hydrophilic, biomimetic, and bio-safe, with human tissue-derived collagen biofunction, has attracted extensive attention worldwide. Herein, we developed a novel method for HA/HLC bio-composite membranes preparation, comprising one-step surface modification-assembly process by which the HLC self-assembles are simultaneously loaded on the oxidized-modified HA (oxi-HA) from the surface/interface micro-scale. Comprehensive material characterizations and in vitro/in vivo biostudies proved that the HLC/oxi-HA composite membranes exhibited significantly enhanced biological activity, hemostatic performances, and wound healing properties compared to that of the pristine HA. The results of this study highlight the great potential of the prepared biomimetic HLC/oxi-HA bio-composites as a new generation of multifunctional HA-based wound-healing materials.


Assuntos
Materiais Biocompatíveis/química , Biomimética/métodos , Colágeno/química , Ácido Hialurônico/química , Engenharia Tecidual/métodos , Alicerces Teciduais/química , Humanos
10.
Medicine (Baltimore) ; 99(32): e21462, 2020 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-32769876

RESUMO

BACKGROUND: Physician burnout has been a global problem that affects severely the mental status among doctors, especially in emergency medicine (EM). However, few studies have focused on emergency medicine physicians, and the published data are inconsistent. Thus, this meta-analysis is performed to systematically evaluate the prevalence of burnout among emergency medicine physicians. METHODS: We systematically searched databases including PubMed, Embase, PsychINFO and the Cochrane Library from inception to September, 2019 for English-language articles. We selected all the original articles those used Maslach Burnout Inventory to assess the prevalence of burnout and its 3 dimensions emotional exhaustion (EE), depersonalization, and personal accomplishment (PA) in emergency medicine physicians. After literature screening, quality evaluation was performed for eligible studies by using the Joanna Briggs Institute (JBI) critical appraisal checklist for studies reporting prevalence data; then, Begg test and Egger test was used to assess publication bias. Pooled prevalence rates were assessed by conducting a meta-analysis using random effects models. Then sensitivity analysis followed to test the stability of the result and detected the source of heterogeneity. RESULTS: A total of 1943 EM physicians provided burnout data. The pooled prevalence rates of high levels of emotional exhaustion, high levels of depersonalization and low levels of PA were 40% (95% CI: 26%-55%; I = 97.4%), 41% (95% CI: 30%-52%; I = 94.5%) and 35% (95% CI: 19%-52%; I = 99.0%), respectively. The mean burnout scores were 23.95 (SD = 11.88) for emotional exhaustion, 11.63 (SD = 6.85) for depersonalization, and 34.69 (SD = 7.71) for PA. CONCLUSIONS: This meta-analysis demonstrate a high level of burnout prevalent in EM physicians that approximately 40% experience high levels of EE and depersonalization. Our findings also suggest that EM physicians are more susceptible to burnout compared with physicians in other departments and other medical staffs in EM. More attention should be payed to mental status of EM physicians and further investigation concerning how to reduce burnout would be beneficial for EM physicians.Registration: INPLASY202060060 in inplasy.com (doi.org/10.37766/inplasy2020.6.0060).


Assuntos
Esgotamento Profissional/epidemiologia , Medicina de Emergência , Médicos/psicologia , Humanos , Médicos/estatística & dados numéricos , Prevalência
11.
J Mater Chem B ; 7(46): 7338-7350, 2019 12 14.
Artigo em Inglês | MEDLINE | ID: mdl-31693046

RESUMO

Hemostatic materials based on collagen and chitin are commonly assessed with regard to their topical absorbability and bioactivity. However, their clinical application faces challenges such as relatively long hemostatic and wound healing times, single function, as well as wound bleeding in patients with blood diseases. Herein, a novel bio-inspired "cotton-like" collagen aggregate/chitin based biomaterial for rapid hemostatic and tissue repair (V-3D-Ag-col) was fabricated by a specific gradient-removal solvent approach. Significantly, for the first time, an advanced collagen aggregate (Ag-col) composed of typical D-periodic cross-striated collagen fibrils and thick collagen fiber bundles was used instead of traditional collagen molecules (Col) to construct a hemostatic material. The target material showed a biomimetic 3D microstructure and "cotton-like" appearance, as expected, which were conducive to platelet adhesion and aggregation. The fabricated V-3D-Ag-col exhibited superior thermo-stability, hemostatic activity and biodegradability. More importantly, V-3D-Ag-col could significantly promote cell growth and proliferation. Further, V-3D-Ag-col could accelerate the wound healing process better than the same material based on conventional collagen (V-3D-Col). In consequence, V-3D-Ag-col has the potential to become a new generation of collagen-absorbable functional hemostatic materials. Furthermore, Ag-col can replace the currently available conventional collagen materials as raw materials for the new generation of collagen-based biomedical materials.


Assuntos
Materiais Biocompatíveis/química , Biomimética , Quitina/química , Colágeno/química , Hemostáticos/química , Animais , Coagulação Sanguínea , Orelha/irrigação sanguínea , Hemostasia , Células Endoteliais da Veia Umbilical Humana , Humanos , Fígado/metabolismo , Teste de Materiais , Camundongos , Músculo Esquelético/metabolismo , Adesividade Plaquetária , Agregação Plaquetária , Coelhos , Ratos , Ratos Sprague-Dawley , Trombose , Engenharia Tecidual , Alicerces Teciduais/química , Cicatrização
12.
Mater Sci Eng C Mater Biol Appl ; 99: 1509-1522, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30889687

RESUMO

Collagen is the most abundant structural protein of connective tissues including skin, tendon, bone and cartilage in mammals. The complicated biosynthesis of nature collagen in vivo, involving numerous intracellular and extracellular steps, causes it to have a multi-hierarchical fibrous architecture. The bioactivity of collagen is mostly depended on its tertiary structure or above. In the past decades, collagen biomaterials have received many attentions in biological applications due to its excellent properties, such as low immunogenicity, biodegradable, biocompatibility, hydrophilicity, easy processing, etc. However, collagen is also suffering from the poor physical and chemical properties (mechanical strength, thermostability, resistance to enzyme and so on). Therefore, the modification of collagen in preparation process is necessary. This review will shed light on the crosslinking methods and the recent advances of collagen-based materials in biomedical applications including skin substitute, bone repair, tendon repair, cartilage repair, neural repair and delivery system.


Assuntos
Materiais Biocompatíveis/química , Tecnologia Biomédica/métodos , Colágeno/química , Animais , Sistemas de Liberação de Medicamentos , Humanos , Modelos Moleculares
13.
IEEE Trans Med Imaging ; 38(2): 617-628, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30183623

RESUMO

One of the methods for stratifying different molecular classes of breast cancer is the Nottingham prognostic index plus, which uses breast cancer relevant biomarkers to stain tumor tissues prepared on tissue microarray (TMA). To determine the molecular class of the tumor, pathologists will have to manually mark the nuclei activity biomarkers through a microscope and use a semi-quantitative assessment method to assign a histochemical score (H-Score) to each TMA core. Manually marking positively stained nuclei is a time-consuming, imprecise, and subjective process, which will lead to inter-observer and intra-observer discrepancies. In this paper, we present an end-to-end deep learning system, which directly predicts the H-Score automatically. Our system imitates the pathologists' decision process and uses one fully convolutional network (FCN) to extract all nuclei region (tumor and non-tumor), a second FCN to extract tumor nuclei region, and a multi-column convolutional neural network, which takes the outputs of the first two FCNs and the stain intensity description image as an input and acts as the high-level decision making mechanism to directly output the H-Score of the input TMA image. To the best of our knowledge, this is the first end-to-end system that takes a TMA image as the input and directly outputs a clinical score. We will present experimental results, which demonstrate that the H-Scores predicted by our model have very high and statistically significant correlation with experienced pathologists' scores and that the H-Score discrepancy between our algorithm and the pathologists is on par with the inter-subject discrepancy between the pathologists.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Aprendizado Profundo , Interpretação de Imagem Assistida por Computador/métodos , Análise Serial de Tecidos/métodos , Algoritmos , Bases de Dados Factuais , Feminino , Humanos , Imuno-Histoquímica
14.
J Hosp Med ; 11(4): 251-6, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26777721

RESUMO

BACKGROUND: Real-time feedback about patients' perceptions of the quality of the care they are receiving could provide physicians the opportunity to address concerns and improve these perceptions as they occur, but physicians rarely if ever receive feedback from patients in real time. OBJECTIVE: To evaluate if real-time patient feedback to physicians improves patient experience. DESIGN: Prospective, randomized, quality-improvement initiative. SETTING: University-affiliated, public safety net hospital. PARTICIPANTS: Patients and hospitalist physicians on general internal medicine units. INTERVENTION: Real-time daily patient feedback to providers along with provider coaching and revisits of patients not reporting optimal satisfaction with their care. MEASUREMENTS: Patient experience scores on 3 provider-specific questions from daily surveys on all patients and Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) scores and percentiles on randomly selected patients. RESULTS: Changes in HCAHPS percentile ranks were substantial (communication from doctors: 60th percentile versus 39th, courtesy and respect of doctors: 88th percentile versus 23rd, doctors listening carefully to patients: 95th percentile versus 57th, and overall hospital rating: 87th percentile versus 6th (P = 0.02 for overall differences in percentiles), but we found no statistically significant difference in the top box proportions for the daily surveys or the HCAHPS survey. The median [interquartile range] top box score for the overall hospital rating question on the HCAHPS survey was higher in the intervention group than in the control group (10 [9, 10] vs 9 [8, 10], P = 0.04). CONCLUSIONS: Real-time feedback, followed by coaching and patient revisits, seem to improve patient experience.


Assuntos
Pesquisas sobre Atenção à Saúde/métodos , Médicos Hospitalares , Hospitalização , Medicina Interna/métodos , Satisfação do Paciente , Qualidade da Assistência à Saúde , Adulto , Idoso , Feminino , Médicos Hospitalares/normas , Humanos , Medicina Interna/normas , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Qualidade da Assistência à Saúde/normas , Fatores de Tempo
15.
Can J Aging ; 35(1): 55-69, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26757886

RESUMO

Equitable access to and utilization of health services is a primary goal for many health care systems, particularly in countries with universal publicly funded systems. Despite concerns regarding potentially adverse implications of the 1990s' health care policy and other reforms, whether and how income inequalities in service utilization changed remains unclear. This study addressed the impact of income on physician and hospital utilization from 1992-2002 among adults aged 50 and older in British Columbia. Those with lower incomes were found less likely to access general practitioner and specialist services but more likely to access hospital services. Income-related disparities in physician care increased over time; hospital care declined. Volume of GP and hospital care was inversely associated with income; these differences increased regarding GP services only. Findings of declines in hospital-care access, accompanied by increasing income-related disparities in physician-services access, show that inequities are increasing within Canada's health care system.


Assuntos
Acessibilidade aos Serviços de Saúde , Disparidades em Assistência à Saúde , Idoso , Idoso de 80 Anos ou mais , Colúmbia Britânica , Estudos de Coortes , Medicina Geral/estatística & dados numéricos , Serviços de Saúde/estatística & dados numéricos , Nível de Saúde , Hospitalização/estatística & dados numéricos , Humanos , Pessoa de Meia-Idade , Programas Nacionais de Saúde/estatística & dados numéricos , Estudos Retrospectivos , Fatores Socioeconômicos
16.
J Mater Chem B ; 2(8): 971-980, 2014 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-32261615

RESUMO

By means of purposeful material design and melt manipulation, we present a highly feasible approach to simultaneously improve the mechanical properties, fatigue and wear resistance of an ultrahigh molecular weight polyethylene (UHMWPE)-based self-reinforced polyethylene (PE) blend for artificial joint replacement. The fluidity of the PE blend was achieved by blending low molecular weight polyethylene (LMWPE) with radiation cross-linked UHMWPE. The use of the cross-linked UHMWPE restrained the molecular diffusion between the LMWPE and UHMWPE phases, and hence increased the content of UHMWPE up to 50 wt% under the premise of desirable fluidity for injection molding. The combination of the shear flow field and pre-additive precursors successfully induced numerous interlocking shish-kebab structures in the LMWPE phase. Mechanical reinforcement was thus attained, where the ultimate tensile strength was significantly improved from 27.6 MPa for the compression-molded UHMWPE to 81.2 MPa for the PE blend, and the impact strength was increased from 29.6 to 35.2 kJ m-2. The fatigue and wear resistance were far superior to those of the compression-molded UHMWPE. Compared to the results reported in our previous study (40 wt% UHMWPE), the increased UHMWPE content caused the LMWPE phase melt to flow faster, thus amplifying the shear rate in the interfacial region between the two phases and depressing the relaxation of oriented molecular chains. The crystalline orientation was preserved, especially in the inner layer, leading to further enhancement of the mechanical properties. These results suggest that such a self-reinforced PE blend is of benefit to lowering the risk of failure and prolonging the life span of the implant under adverse conditions.

17.
Surg Endosc ; 25(1): 249-54, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20585963

RESUMO

BACKGROUND: Five-year graft survival in the pediatric lung transplant (LTxp) population is less than 50%, with obliterative bronchiolitis (OB) the leading cause of death at 1, 3, and 5 years post-transplant. Bronchiolitis obliterans syndrome (BOS), defined using spirometry values, is the clinical surrogate for the histological diagnosis of obliterative bronchiolitis. Surgical correction of documented gastroesophageal reflux disease (GERD) has been proposed as a means to potentially delay the onset of BOS and prolong allograft survival in adults before or after lung transplantation but only one such study exists in children. We have examined the safety and possible benefits of laparoscopic antireflux surgery in pediatric patients following lung (LTxp) and heart-lung transplantation (HLTxp). METHODS: An Institutional Review Board (IRB)-approved retrospective chart review was performed to evaluate the outcomes and complications of laparoscopic antireflux surgery in pediatric lung and heart-lung transplant patients. Spirometry data were collected for BOS staging using BOS criteria for children. RESULTS: Twenty-five lung and heart-lung transplants were performed between January 2003 and July 2009. Eleven transplant recipients, including six double-lung and five heart-lung (HLTxp), with a median age of 11.7 years (range 5.1-18.4 years), underwent a total of 12 laparoscopic Nissen fundoplications at a median of 427 days after transplant (range 51-2310 days). GERD was determined based upon clinical impression, pH probe study, gastric emptying study, and/or esophagram in all patients. Three patients already had a gastrostomy tube in place and two had one placed at the time of fundoplication. There were no conversions to open surgery, 30-day readmissions, or 30-day mortalities. Complications included one exploratory laparoscopy for free air 6 days after laparoscopic Nissen fundoplication for a gastric perforation that had spontaneously sealed. Another patient required a revision laparoscopic Nissen 822 days following the initial fundoplication for a paraesophageal hernia and recurrent GERD. The average length of hospital stay was 4.4 ± 1.7 days. Nine of the 12 fundoplications were performed in patients with baseline spirometry values prior to fundoplication and who could also complete spirometry reliably. One of these nine operations was associated with improvement in BOS stage 6 months after fundoplication; seven were associated with no change in BOS stage; and one was associated with a decline in BOS stage. CONCLUSION: It is feasible to perform laparoscopic Nissen fundoplication in pediatric lung and heart-lung transplant recipients without mortality or significant morbidity for the treatment of GERD. The real effect on pulmonary function cannot be assessed due to our small sample size and lack of reproducible spirometry in our younger patients. Additional studies are needed to elucidate the relationship between antireflux surgery and the potential for improving pulmonary allograft function and survival in children which has been previously observed in adult patients.


Assuntos
Bronquiolite Obliterante/prevenção & controle , Fundoplicatura , Refluxo Gastroesofágico/cirurgia , Transplante de Coração-Pulmão , Laparoscopia/métodos , Transplante de Pulmão , Complicações Pós-Operatórias/prevenção & controle , Adolescente , Bronquiolite Obliterante/etiologia , Bronquiolite Obliterante/mortalidade , Bronquiolite Obliterante/fisiopatologia , Criança , Pré-Escolar , Estudos de Viabilidade , Feminino , Volume Expiratório Forçado , Refluxo Gastroesofágico/complicações , Humanos , Masculino , Fluxo Máximo Médio Expiratório , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/mortalidade , Complicações Pós-Operatórias/fisiopatologia , Estudos Retrospectivos , Resultado do Tratamento
18.
J Altern Complement Med ; 16(9): 995-1001, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20809808

RESUMO

OBJECTIVES: This article examines trends in and predictors of publicly subsidized chiropractic use from 1991 to 2000, a decade characterized by health care system reforms throughout North America. SAMPLE: The sample included adults age 50+ who visited a publicly subsidized chiropractor in the Canadian province of British Columbia during the study period. DESIGN: Administrative claims data for chiropractic service use were drawn from the Medical Services Plan (MSP) Master file in the British Columbia Linked Health Data resource. The MSP Master file contains claims reported for every provincially insured medical service and supplementary health benefit including chiropractic visits. RESULTS: Joinpoint regression analyses demonstrate that while annual rates of chiropractic users did not change over the decade, visit rates decreased during this period. Predictors of a greater number of chiropractic visits include increasing age, female gender, urban residence, low to moderate income, and use of chiropractic services earlier in the decade. CONCLUSIONS: The trend toward decreasing visit rates over the 1990s both conflicts with and is consistent with findings from other North American chiropractic studies using similar time periods. Results indicating that low and moderate income and advancing age predict more frequent chiropractic service are novel. However, given that lower income and older individuals were exempted from chiropractic service limits during this period, these results suggest support for the responsive nature of chiropractic use to financial barriers.


Assuntos
Quiroprática/tendências , Programas Nacionais de Saúde , Fatores Etários , Idoso , Colúmbia Britânica , Quiroprática/economia , Quiroprática/estatística & dados numéricos , Feminino , Humanos , Renda , Masculino , Pessoa de Meia-Idade , Visita a Consultório Médico/economia , Visita a Consultório Médico/estatística & dados numéricos , Visita a Consultório Médico/tendências , Análise de Regressão , Fatores Sexuais , População Urbana
19.
BMC Health Serv Res ; 6: 104, 2006 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-16914056

RESUMO

BACKGROUND: Researchers and policy makers have focussed on the development of indicators to help monitor the success of regionalization, primary care reform and other health sector restructuring initiatives. Certain indicators are useful in examining issues of equity in service provision, especially among older populations, regardless of where they live. AHRs are used as an indicator of primary care system efficiency and thus reveal information about access to general practitioners. The purpose of this paper is to examine trends in avoidable hospitalization rates (AHRs) during a period of time characterized by several waves of health sector restructuring and regionalization in British Columbia. AHRs are examined in relation to non-avoidable and total hospitalization rates as well as by urban and rural geography across the province. METHODS: Analyses draw on linked administrative health data from the province of British Columbia for 1990 through 2000 for the population aged 50 and over. Joinpoint regression analyses and t-tests are used to detect and describe trends in the data. RESULTS: Generally speaking, non-avoidable hospitalizations constitute the vast majority of hospitalizations in a given year (i.e. around 95%) with AHRs constituting the remaining 5% of hospitalizations. Comparing rural areas and urban areas reveals that standardized rates of avoidable, non-avoidable and total hospitalizations are consistently higher in rural areas. Joinpoint regression results show significantly decreasing trends overall; lines are parallel in the case of avoidable hospitalizations, and lines are diverging for non-avoidable and total hospitalizations, with the gap between rural and urban areas being wider at the end of the time interval than at the beginning. CONCLUSION: These data suggest that access to effective primary care in rural communities remains problematic in BC given that rural areas did not make any gains in AHRs relative to urban areas under recent health sector restructuring initiatives. It remains important to continue to monitor the discrepancy between them as a reflection of inequity in service provision. In addition, it is important to consider alternative explanations for the observed trends paying particular attention to the needs of rural and urban populations and the factors influencing local service provision.


Assuntos
Acessibilidade aos Serviços de Saúde/estatística & dados numéricos , Mau Uso de Serviços de Saúde/tendências , Hospitalização/tendências , Regionalização da Saúde/normas , Serviços de Saúde Rural/provisão & distribuição , Serviços Urbanos de Saúde/provisão & distribuição , Distribuição por Idade , Colúmbia Britânica/epidemiologia , Geografia , Pesquisas sobre Atenção à Saúde , Mau Uso de Serviços de Saúde/estatística & dados numéricos , Hospitalização/estatística & dados numéricos , Humanos , Atenção Primária à Saúde/organização & administração , Análise de Regressão , Fatores Socioeconômicos
20.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-232929

RESUMO

In the process of acid hydrolysis of medical absorbent cotton, we have discovered that some of the domestic manufactured medical absorbent cotton is mixed with wasted non-cotton chemical fiber. If the cotton is used in medical treatments, the chemical fiber will cause irritation, allergy and inflammation, so it's very harmful. But the non-cotton fiber content is not stipulated in the standard of YY0330-2002, and no testing method for it is available. In this paper we discuss the existent quality problems, the control and the test method for non-cotton chemical fiber in medical absorbent cotton.


Assuntos
Bandagens , Padrões de Referência , Fibra de Algodão , Controle de Qualidade
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