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1.
Mater Sci Eng C Mater Biol Appl ; 108: 110359, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31923938

RESUMO

The natural biodegradabilty of porous silicon (pSi) in physiological media limits its wider usage for implantable systems. We report the stabilization of porous silicon (pSi) membranes by chemical surface oxidation using RCA1 and RCA2 protocols, which was followed by a PEGylation process using a silane-PEG. These surface modifications stabilized the pSi to allow a long period of immersion in PBS, while leaving the pSi surface sufficiently hydrophilic for good filtration and diffusion of several biomolecules of different sizes without any blockage of the pSi structure. The pore sizes of the pSi membranes were between 5 and 20 nm, with the membrane thickness around 70 µm. The diffusion coefficient for fluorescein through the membrane was 2 × 10-10 cm2 s-1, and for glucose was 2.2 × 10-9 cm2 s-1. The pSi membrane maintained that level of glucose diffusion for one month of immersion in PBS. After 2 months immersion in PBS the pSi membrane continued to operate, but with a reduced glucose diffusion coefficient. The chemical stabilization of pSi membranes provided almost 1 week stable and functional biomolecule transport in blood plasma and opens the possibility for its short-term implantation as a diffusion membrane in biocompatible systems.

2.
Anesth Analg ; 129(5): e159-e162, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31613812

RESUMO

This study compared anesthesiology residency graduates' written certification examination performance before and after the American Board of Anesthesiology (ABA) introduced the staged examination system. After equating test scores using common test items, the first 2 cohorts (2013, 2014) in the staged system scored 7.1 points and 8.3 points higher than the 2011 baseline cohort in the former examination system. The 2013 and 2014 cohorts' pass rates (94.2% and 95.9%) were also higher than the 2011 and 2012 cohorts (91.9% and 92.6%) if a common standard had been applied. The staged examination system may be associated with improved knowledge of anesthesiology graduates.

3.
Chem Commun (Camb) ; 55(87): 13152-13155, 2019 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-31617527

RESUMO

We designed a supported lipid bilayer (SLB) biomimetic membrane system that comprised polyaniline (PANI) to support a lipid bilayer membrane that incorporated Na+/H+ transporter proteins (NhaA) to give the system the capability of controllable electrogenic ion transport. The high turnover rate of NhaA (∼105 per min) provides the basis for this PANI-SLB-NhaA system to be a high-speed rechargeable biocapacitor that functions as a low-energy-consuming fast switch for biological engineering applications.


Assuntos
Compostos de Anilina/metabolismo , Materiais Biomiméticos/metabolismo , Técnicas Biossensoriais , Proteínas de Escherichia coli/metabolismo , Bicamadas Lipídicas/metabolismo , Trocadores de Sódio-Hidrogênio/metabolismo , Compostos de Anilina/química , Materiais Biomiméticos/química , Espectroscopia Dielétrica , Eletrodos , Proteínas de Escherichia coli/química , Ouro/química , Ouro/metabolismo , Bicamadas Lipídicas/química , Trocadores de Sódio-Hidrogênio/química
4.
Am J Manag Care ; 25(10): e304-e309, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31622070

RESUMO

OBJECTIVES: To determine the patient's perception of the role of an anesthesiologist and the patient's expectations of their anesthesiologist and their anesthesia care. STUDY DESIGN: Questionnaire survey. METHODS: A total of 170 patients attending the preanesthesia clinic answered a survey prior to their clinic interview and another survey the day after their surgery. The questions pertained to their perception of the role of the anesthesia provider, their expectations, and their level of satisfaction. RESULTS: A majority (>75%) of the participants had high expectations of their anesthesia provider. The satisfaction scores were higher among those who felt that their expectations were met and among those who felt that the anesthesiologist explained to them how they would feel after anesthesia. CONCLUSIONS: Because satisfaction is a fulfillment of one's expectations, understanding what the patient expects from their anesthesiologist is the initial step to improve satisfaction scores. The onus is on the anesthesiologist to educate the patient about their role, to set realistic expectations of the postoperative course, and to involve the patient in decisions regarding their anesthesia care.

5.
Stud Health Technol Inform ; 264: 1169-1173, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31438109

RESUMO

A learning management system (LMS) used for the initial training of health professionals has been rejected by students. Our study aimed to explain the reason of this rejection. We performed this evaluation on a sample of health students in 2012 and 2017 (n = 144). We used scales from the literature (Technology Acceptance Model, General Self-Efficacy Scale, LMS-Self-Efficacy Scale), and studied the social representation of the LMS. The system seemed accessible and useful, but unfortunately with similarities to the system used in a traumatic student environment. Health students using the system did not have a lower self-efficacy. Although the LMS seemed relevant to students, its initial rejection might have been due to a confounding context that created confusion in the acceptability of the tool. To conclude, there is a need to create new dematerialized course formats but with strong tutorship to improve the usage of the technologies by students.


Assuntos
Instrução por Computador , Autoeficácia , Pessoal de Saúde , Humanos , Aprendizagem , Estudantes
6.
Anesth Analg ; 2019 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-31166233

RESUMO

This study compared anesthesiology residency graduates' written certification examination performance before and after the American Board of Anesthesiology (ABA) introduced the staged examination system. After equating test scores using common test items, the first 2 cohorts (2013, 2014) in the staged system scored 7.1 points and 8.3 points higher than the 2011 baseline cohort in the former examination system. The 2013 and 2014 cohorts' pass rates (94.2% and 95.9%) were also higher than the 2011 and 2012 cohorts (91.9% and 92.6%) if a common standard had been applied. The staged examination system may be associated with improved knowledge of anesthesiology graduates.

8.
Biotechnol J ; 13(12): e1800463, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30457706

RESUMO

A major problem for the detection of cancer biomarkers in plasma or serum is that common clinical practice does not require the patient to be in a fasting state. Considering that lipoproteins are the main population affected by food intake, the authors hypothesized that biomarkers could be embedded in lipid particles and thereby opens a new avenue for detection. Using the recently published biomarker, soluble VE-cadherin (sVE), the authors tested our hypothesis using techniques of biophysics, biochemistry and the tools of nanobiotechnology on serum samples from kidney cancer patients (n = 106). Optical density as well as contact angle measurements of serum revealed heterogeneity in the particle content of the serum samples. Isolation of the lipidic moieties by ultracentrifugation showed that sVE was detected in this compartment. Further, isolation of lipoprotein subclasses by precipitation with sodium phosphotungstate and MgCl2 , showed that HDL carried the majority of sVE. Immunoprecipitation of sVE confirmed that it was associated with Apolipoprotein A1, a major compound of HDL. Using a biomimetic lipid bilayer membrane coupled with impedance spectroscopy the authors quantified, in real-time, that the sVE adsorbed to the lipid bilayer membrane without altering its structure. Taken together, these results show for the first time a direct interaction of a cancer biomarker with lipids. The authors anticipate these results to prompt fasting for future blood tests for large-scale studies in the biomarkers research field.


Assuntos
Biomarcadores Tumorais/sangue , Materiais Biomiméticos , Colesterol/sangue , Antígenos CD/sangue , Apolipoproteína A-I/sangue , Biotecnologia , Caderinas/sangue , Células HEK293 , Humanos , Imunoprecipitação , Neoplasias Renais/sangue , Lipoproteínas/sangue , Modelos Teóricos , Nanotecnologia
9.
Biotechnol J ; 13(12): e1800102, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30367543

RESUMO

This review takes an approach to implanted medical devices that considers whether the intention of the implanted device is to have any communication of energy or materials with the body. The first part describes some specific examples of three different classes of implants, analyzed with regards to the type of signal sent to cells. Through several examples, the authors describe that a one way signaling to the body leads to encapsulation or degradation. In most cases, those phenomena do not lead to major problems. However, encapsulation or degradation are critical for new kinds of medical devices capable of duplex communication, which are defined in this review as symbiotic devices. The concept the authors propose is that implanted medical devices that need to be symbiotic with the body also need to be designed with an intended duplex communication of energy and materials with the body. This extends the definition of a biocompatible system to one that requires stable exchange of materials between the implanted device and the body. Having this novel concept in mind will guide research in a new field between medical implant and regenerative medicine to create actual symbiotic devices.


Assuntos
Biotecnologia , Equipamentos e Provisões , Nanotecnologia , Próteses e Implantes , Materiais Biocompatíveis , Humanos , Medicina Regenerativa
10.
Bioelectrochemistry ; 124: 57-72, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30007207

RESUMO

There is a growing interest in the design and engineering of operational biofuel cells that can be implanted. This review highlights the recent progress in the electrochemistry of biofuel cell technologies, but with a particular emphasis on the medical and physiological aspects that impact the biocompatibility of biofuel cells operating inside a living body. We discuss the challenge of supplying power to implantable medical devices, with regard to the limitations of lithium battery technology and why implantable biofuel cells can be a promising alternative to provide the levels of power required for medical devices. In addition to the challenge of designing a biofuel cell that provides a stable level of sufficient power, the review highlights the biocompatibility and biofouling problems of implanting a biofuel cell that have a major impact on the availability of the substrates inside body that provide fuel for the biofuel cell. These physiological challenges and associated ethical considerations are essential to consider for biofuel cells that are designed to be implanted for long-term operation inside a living animal and eventually to human clinical applications.


Assuntos
Materiais Biocompatíveis , Fontes de Energia Bioelétrica , Técnicas Eletroquímicas/instrumentação , Animais , Eletrodos
12.
J Clin Anesth ; 46: 101-111, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29505959

RESUMO

STUDY OBJECTIVE: Wrong-site nerve blocks (WSBs) are a significant, though rare, source of perioperative morbidity. WSBs constitute the most common type of perioperative wrong-site procedure reported to the Pennsylvania Patient Safety Authority. This systematic literature review aggregates information about the incidence, patient consequences, and conditions that contribute to WSBs, as well as evidence-based methods to prevent them. DESIGN: A systematic search of English-language publications was performed, using the PRISMA process. MAIN RESULTS: Seventy English-language publications were identified. Analysis of four publications reporting on at least 10,000 blocks provides a rate of 0.52 to 5.07 WSB per 10,000 blocks, unilateral blocks, or "at risk" procedures. The most commonly mentioned potential consequence was local anesthetic toxicity. The most commonly mentioned contributory factors were time pressure, personnel factors, and lack of site-mark visibility (including no site mark placed). Components of the block process that were addressed include preoperative nerve-block verification, nerve-block site marking, time-outs, and the healthcare facility's structure and culture of safety. DISCUSSION: A lack of uniform reporting criteria and divergence in the data and theories presented may reflect the variety of circumstances affecting when and how nerve blocks are performed, as well as the infrequency of a WSB. However, multiple authors suggest three procedural steps that may help to prevent WSBs: (1) verify the nerve-block procedure using multiple sources of information, including the patient; (2) identify the nerve-block site with a visible mark; and (3) perform time-outs immediately prior to injection or instillation of the anesthetic. Hospitals, ambulatory surgical centers, and anesthesiology practices should consider creating site-verification processes with clinician input and support to develop sustainable WSB-prevention practices.


Assuntos
Anestésicos Locais/efeitos adversos , Erros Médicos/prevenção & controle , Bloqueio Nervoso/efeitos adversos , Segurança do Paciente , Anestésicos Locais/administração & dosagem , Humanos , Erros Médicos/estatística & dados numéricos , Bloqueio Nervoso/métodos , Fatores de Tempo
13.
Trends Biotechnol ; 35(11): 1035-1048, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28927991

RESUMO

We highlight the disposition of various cell types to self-organize into complex organ-like structures without necessarily the support of any stromal cells, provided they are placed into permissive 3D culture conditions. The goal of generating organoids reproducibly and efficiently has been hampered by poor understanding of the exact nature of the intrinsic cell properties at the origin of organoid generation, and of the signaling pathways governing their differentiation. Using microtechnologies like microfluidics to engineer organoids would create opportunities for single-cell genomics and high-throughput functional genomics to exhaustively characterize cell intrinsic properties. A more complete understanding of the development of organoids would enhance their relevance as models to study organ morphology, function, and disease and would open new avenues in drug development and regenerative medicine.


Assuntos
Técnicas de Cultura de Células , Genômica , Técnicas Analíticas Microfluídicas , Organoides , Medicina Regenerativa , Animais , Técnicas de Cultura de Células/instrumentação , Técnicas de Cultura de Células/métodos , Genômica/instrumentação , Genômica/métodos , Humanos , Técnicas Analíticas Microfluídicas/instrumentação , Técnicas Analíticas Microfluídicas/métodos , Organoides/citologia , Organoides/crescimento & desenvolvimento , Medicina Regenerativa/instrumentação , Medicina Regenerativa/métodos
14.
Langmuir ; 33(38): 9988-9996, 2017 09 26.
Artigo em Inglês | MEDLINE | ID: mdl-28845995

RESUMO

OprF has a central role in Pseudomonas aeruginosa virulence and thus provides a putative target for either vaccines or antibiotic cofactors that could overcome the bacterium's natural resistance to antibiotics. Here we describe a procedure to optimize the production of highly pure and functional OprF porins that are then incorporated into a tethered lipid bilayer. This is a stable biomimetic system that provides the capability to investigate structural aspects and function of OprF using and neutron reflectometry and electrical impedance spectroscopy. The recombinant OprF produced using the optimized cell-free procedure yielded a quantity of between 0.5 to 1.0 mg/mL with a purity ranging from 85 to 91% in the proteoliposomes. The recombinant OprF is capable of binding IFN-γ and is correctly folded in the proteoliposomes. Because OprF proteins form pores the biomimetic system allowed the measurement of OprF conductance using impedance spectroscopy. The neutron reflectometry measurements showed that the OprF protein is incorporated into the lipid bilayer but with parts of the protein in both the regions above and below the lipid bilayer. Those structural aspects are coherent with the current assumed structure of a transmembrane N-terminal domain composed by eight stranded beta-barrels and a globular C-terminal domain located in the periplasm. Currently there are no crystal structures available for OprF. The experimental model system that we describe provides a basis for further fundamental studies of OprF and particularly for the ongoing biotechnological development of OprF as a target for antibacterial drugs.


Assuntos
Pseudomonas aeruginosa , Fenômenos Biofísicos , Bicamadas Lipídicas , Porinas , Conformação Proteica
15.
Sci Rep ; 7(1): 3399, 2017 06 13.
Artigo em Inglês | MEDLINE | ID: mdl-28611396

RESUMO

The structure of the p7 viroporin, an oligomeric membrane protein ion channel involved in the assembly and release of the hepatitis C virus, was determined from proteins expressed and inserted directly into supported model lipid membranes using cell-free protein expression. Cell-free protein expression allowed (i ) high protein concentration in the membrane, (ii ) control of the protein's isotopic constitution, and (iii ) control over the lipid environment available to the protein. Here, we used cell-free protein synthesis to directly incorporate the hepatitis C virus (HCV) p7 protein into supported lipid bilayers formed from physiologically relevant lipids (POPC or asolectin) for both direct structural measurements using neutron reflectivity (NR) and conductance measurements using electrical impedance spectroscopy (EIS). We report that HCV p7 from genotype 1a strain H77 adopts a conical shape within lipid bilayers and forms a viroporin upon oligomerization, confirmed by EIS conductance measurements. This combination of techniques represents a novel approach to the study of membrane proteins and, through the use of selective deuteration of particular amino acids to enhance neutron scattering contrast, has the promise to become a powerful tool for characterizing the protein conformation in physiologically relevant environments and for the development of biosensor applications.


Assuntos
Membrana Celular/química , Bicamadas Lipídicas/química , Lipídeos de Membrana/química , Nêutrons , Biossíntese de Proteínas , Proteínas Virais/química , Membrana Celular/metabolismo , Bicamadas Lipídicas/metabolismo , Lipídeos de Membrana/metabolismo , Modelos Moleculares , Conformação Proteica , Proteínas Virais/metabolismo
16.
Eur Phys J E Soft Matter ; 39(12): 123, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27966072

RESUMO

Tethered lipid bilayer membranes (tBLM) are planar membranes composed of free lipids and molecules tethered to a solid planar substrate providing a useful model of biological membranes for a wide range of biophysical studies and biotechnological applications. The properties of the tBLM depend on the free lipids and on the chemistry of the tethering molecules. We present a nanoscale characterization of a tBLM composed of deuterated 1,2-dimyristoyl-sn-glycero-3-phosphocholine (d-DMPC) free lipids, benzyl disulfide undecaethylene glycol phytanol (DLP) tethering molecules, and benzyl disulfiide tetraethylene glycol polar spacer molecules (PSM) used to control the areal density of tethering molecules through coadsorption. The use of selected isotopic substitution provides a way to distinguish the conformation and location of the tethered lipids from the free lipids and to elucidate how the two components influence the structure of the tBLM. These findings provide useful information to optimise the insertion of transmembrane proteins into the tethered bilayer system.


Assuntos
Ouro/química , Bicamadas Lipídicas/química , Nanoestruturas/química , Materiais Biomiméticos/química , Membrana Celular/química , Dimiristoilfosfatidilcolina/química , Conformação Molecular
17.
Med Sci (Paris) ; 32(8-9): 771-3, 2016.
Artigo em Francês | MEDLINE | ID: mdl-27615187

RESUMO

An implanted biofuel cell (IBFC) is a novel device that provides the means to create electricity from glucose and oxygen, using an original architecture for the IBFC that provides efficient work inside a living organism. In the future these IBFCs will be required to power implanted devices to assist failing physiological functions in humans. The active ingredients of such IBFCs are glucose oxidase at the anode and laccase at the cathode. These enzymes are entrapped in a 3D network of conductive and insulated materials. This publication solves the issue of the sterilization of such a complex device, using gamma irradiation. A 12kGy dose was sufficient to show absence of implant infection in all the implantations performed. We also prove in vitro functioning of both bioelectrodes with a high dose of 42kGy.


Assuntos
Fontes de Energia Bioelétrica , Eletrodos Implantados , Enzimas Imobilizadas , Glucose/metabolismo , Oxigênio/metabolismo , Animais , Técnicas Biossensoriais , Enzimas Imobilizadas/metabolismo , Glucose Oxidase/metabolismo , Humanos , Lacase/metabolismo
18.
Trends Biotechnol ; 34(9): 757-769, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27497676

RESUMO

We discuss the current challenges and future prospects of flow-based organoid models and 3D self-assembling scaffolds. The existing paradigm of 3D culture suffers from a lack of control over organoid size and shape; can be an obstacle for cell harvesting and extended cellular and molecular analysis; and does not provide access to the function of exocrine glands. Moreover, existing organ-on-chip models are mostly composed of 2D extracellular matrix (ECM)-coated elastomeric membranes that do not mimic real organ architectures. A new comprehensive 3D toolbox for cell biology has emerged to address some of these issues. Advances in microfabrication and cell-culturing approaches enable the engineering of sophisticated models that mimic organ 3D architectures and physiological conditions, while supporting flow-based drug screening and secretomics-based diagnosis.


Assuntos
Técnicas de Cultura de Células , Modelos Biológicos , Organoides , Engenharia Tecidual , Tecidos Suporte , Células Cultivadas , Matriz Extracelular , Humanos , Técnicas Analíticas Microfluídicas , Análise Serial de Tecidos
19.
Ann Pharmacother ; 50(3): 161-71, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26706861

RESUMO

BACKGROUND: Gallstone disease is a leading cause of morbidity in Western countries and carries a high economic burden. Statin medications decrease hepatic cholesterol biosynthesis and may, therefore, lower the risk of cholesterol cholelithiasis by reducing the cholesterol concentration in the bile. Population-based evidence, however, is sparse. OBJECTIVE: To assess the risk of gallbladder diseases among statin users compared with nonusers in an American patient cohort. METHODS: We performed a retrospective cohort study of patients enrolled in the San Antonio Tricare health system using data between October 2003 and March 2012. We defined 2 groups: statin users (use for 90 days or greater) and nonusers (no prior statin). A propensity score based on 82 variables was generated to match statin users and nonusers 1:1. Outcomes included incidence of cholelithiasis, biliary tract diseases, and gallbladder procedures. RESULTS: A total of 43 438 patients were identified; 13 626 (31.4%) were statin users, and 29 812 (68.6%) were nonusers. We matched 6342 pairs of statin users and nonusers based on propensity score. The odds ratios (ORs) in statin users in comparison to nonusers were similar for cholelithiasis (OR = 0.86; 95% CI = 0.73, 1.02), biliary tract disease (OR = 0.85; 95% CI = 0.67-1.08), and gall bladder procedures (OR = 0.85; 95% CI = 0.69, 1.04). CONCLUSIONS: Statin use was not significantly associated with either an increased or decreased risk of cholelithiasis or gallbladder disease.


Assuntos
Doenças Biliares/induzido quimicamente , Inibidores de Hidroximetilglutaril-CoA Redutases/efeitos adversos , Adulto , Idoso , Doenças Biliares/epidemiologia , Colelitíase/induzido quimicamente , Colelitíase/epidemiologia , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Razão de Chances , Pontuação de Propensão , Estudos Retrospectivos , Risco
20.
Prep Biochem Biotechnol ; 46(6): 546-51, 2016 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-26443900

RESUMO

The mitochondrial voltage-dependent anion channel (VDAC) is a pivotal protein since it provides the major transport pathway between the cytosol and the mitochondrial intermembrane space and it is implicated in cell apoptosis by functioning as a gatekeeper for the trafficking of mitochondrial death molecules. VDAC is a beta-barrel channel with a large conductance, and we use it as a model transport protein for the design of biomimetic systems. To overcome the limitations of classical overexpression methods for producing and purifying membrane proteins (MPs) we describe here the use of an optimized cell-free system. In a one-step reaction VDAC is obtained directly integrated into liposomes and purified by ultracentrifugation. We then combine proteoliposomes with different bilayers models in order to validate VDAC insertion and functionality. This VDAC biomimetic model is the first example validating the use of a cell-free expression system for production of MPs into liposomes and tethered bilayers as a toolbox to build a wide range of biomimetic devices.


Assuntos
Biomimética , Lipossomos , Membranas Artificiais , Canais de Ânion Dependentes de Voltagem/metabolismo , Western Blotting , Sistema Livre de Células , Dicroísmo Circular , Clonagem Molecular , Microscopia Imunoeletrônica , Canais de Ânion Dependentes de Voltagem/genética
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