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1.
Cell Mol Life Sci ; 80(10): 287, 2023 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-37689602

RESUMO

Voltage-gated sodium (NaV) channels are transmembrane proteins that play a critical role in electrical signaling in the nervous system and other excitable tissues. µ-Conotoxins are peptide toxins from the venoms of marine cone snails (genus Conus) that block NaV channels with nanomolar potency. Most species of the subgenera Textilia and Afonsoconus are difficult to acquire; therefore, their venoms have yet to be comprehensively interrogated for µ-conotoxins. The goal of this study was to find new µ-conotoxins from species of the subgenera Textilia and Afonsoconus and investigate their selectivity at human NaV channels. Using RNA-seq of the venom gland of Conus (Textilia) bullatus, we identified 12 µ-conotoxin (or µ-conotoxin-like) sequences. Based on these sequences we designed primers which we used to identify additional µ-conotoxin sequences from DNA extracted from historical specimens of species from Textilia and Afonsoconus. We synthesized six of these µ-conotoxins and tested their activity on human NaV1.1-NaV1.8. Five of the six synthetic peptides were potent blockers of human NaV channels. Of these, two peptides (BuIIIB and BuIIIE) were potent blockers of hNaV1.3. Three of the peptides (BuIIIB, BuIIIE and AdIIIA) had submicromolar activity at hNaV1.7. This study serves as an example of the identification of new peptide toxins from historical DNA and provides new insights into structure-activity relationships of µ-conotoxins with activity at hNaV1.3 and hNaV1.7.


Assuntos
Conotoxinas , Caramujo Conus , Toxinas Biológicas , Humanos , Animais , Conotoxinas/farmacologia , Proteínas de Membrana , Canais de Sódio/genética
2.
J Perinat Med ; 46(8): 934-941, 2018 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-29451862

RESUMO

Background Following neonatal resuscitation program (NRP) training, decay in clinical skills can occur. Simulation-based deliberate practice (SBDP) has been shown to maintain NRP skills to a variable extent. Our study objectives were (a) to determine whether a single 30 min simulation-based intervention that incorporates SBDP and mastery learning (ML) can effectively restore skills and prevent skill decay and (b) to compare different timing options. Methods Following NRP certification, pediatric residents were randomly assigned to receive a video-recorded baseline assessment plus SBDP-ML refresher education at between 6 and 9 months (early) or between 9 and 12 months (late). One year following initial certification, participants had repeat skill retention videotaped evaluations. Participants were scored by blinded NRP instructors using validated criteria scoring tools and assigned a global performance rating score (GRS). Results Twenty-seven participants were included. Residents in both early and late groups showed significant skill decay 7 and 10 months after initial NRP. SBDP-ML booster sessions significantly improved participants' immediate NRP performance scores (p<0.001), which persisted for 2 months, but were again lower 4 months later. Conclusions NRP skills may be boosted to mastery levels after a short SBDP-ML intervention and do not appear to significantly decline after 2 months. Brief booster training could potentially serve as a useful supplement to traditional NRP training for pediatric residents.


Assuntos
Competência Clínica/estatística & dados numéricos , Pediatria/educação , Ressuscitação/educação , Treinamento por Simulação/métodos , Feminino , Humanos , Internato e Residência , Masculino
3.
J Biol Chem ; 291(13): 7205-20, 2016 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-26817840

RESUMO

Cone snail toxins are well known blockers of voltage-gated sodium channels, a property that is of broad interest in biology and therapeutically in treating neuropathic pain and neurological disorders. Although most conotoxin channel blockers function by direct binding to a channel and disrupting its normal ion movement, conotoxin µO§-GVIIJ channel blocking is unique, using both favorable binding interactions with the channel and a direct tether via an intermolecular disulfide bond. Disulfide exchange is possible because conotoxin µO§-GVIIJ contains anS-cysteinylated Cys-24 residue that is capable of exchanging with a free cysteine thiol on the channel surface. Here, we present the solution structure of an analog of µO§-GVIIJ (GVIIJ[C24S]) and the results of structure-activity studies with synthetic µO§-GVIIJ variants. GVIIJ[C24S] adopts an inhibitor cystine knot structure, with two antiparallel ß-strands stabilized by three disulfide bridges. The loop region linking the ß-strands (loop 4) presents residue 24 in a configuration where it could bind to the proposed free cysteine of the channel (Cys-910, rat NaV1.2 numbering; at site 8). The structure-activity study shows that three residues (Lys-12, Arg-14, and Tyr-16) located in loop 2 and spatially close to residue 24 were also important for functional activity. We propose that the interaction of µO§-GVIIJ with the channel depends on not only disulfide tethering via Cys-24 to a free cysteine at site 8 on the channel but also the participation of key residues of µO§-GVIIJ on a distinct surface of the peptide.


Assuntos
Conotoxinas/química , Dissulfetos/química , Proteínas Musculares/química , Canal de Sódio Disparado por Voltagem NAV1.2/química , Bloqueadores dos Canais de Sódio/química , Canais de Sódio/química , Sequência de Aminoácidos , Animais , Sítios de Ligação , Conotoxinas/síntese química , Cristalografia por Raios X , Expressão Gênica , Modelos Moleculares , Dados de Sequência Molecular , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Mutação , Canal de Sódio Disparado por Voltagem NAV1.2/genética , Canal de Sódio Disparado por Voltagem NAV1.2/metabolismo , Ligação Proteica , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Ratos , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Caramujos/química , Bloqueadores dos Canais de Sódio/síntese química , Canais de Sódio/genética , Canais de Sódio/metabolismo , Técnicas de Síntese em Fase Sólida , Relação Estrutura-Atividade
4.
Proc Natl Acad Sci U S A ; 111(7): 2758-63, 2014 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-24497506

RESUMO

A cone snail venom peptide, µO§-conotoxin GVIIJ from Conus geographus, has a unique posttranslational modification, S-cysteinylated cysteine, which makes possible formation of a covalent tether of peptide to its target Na channels at a distinct ligand-binding site. µO§-conotoxin GVIIJ is a 35-aa peptide, with 7 cysteine residues; six of the cysteines form 3 disulfide cross-links, and one (Cys24) is S-cysteinylated. Due to limited availability of native GVIIJ, we primarily used a synthetic analog whose Cys24 was S-glutathionylated (abbreviated GVIIJSSG). The peptide-channel complex is stabilized by a disulfide tether between Cys24 of the peptide and Cys910 of rat (r) NaV1.2. A mutant channel of rNaV1.2 lacking a cysteine near the pore loop of domain II (C910L), was >10(3)-fold less sensitive to GVIIJSSG than was wild-type rNaV1.2. In contrast, although rNaV1.5 was >10(4)-fold less sensitive to GVIIJSSG than NaV1.2, an rNaV1.5 mutant with a cysteine in the homologous location, rNaV1.5[L869C], was >10(3)-fold more sensitive than wild-type rNaV1.5. The susceptibility of rNaV1.2 to GVIIJSSG was significantly altered by treating the channels with thiol-oxidizing or disulfide-reducing agents. Furthermore, coexpression of rNaVß2 or rNaVß4, but not that of rNaVß1 or rNaVß3, protected rNaV1.1 to -1.7 (excluding NaV1.5) against block by GVIIJSSG. Thus, GVIIJ-related peptides may serve as probes for both the redox state of extracellular cysteines and for assessing which NaVß- and NaVα-subunits are present in native neurons.


Assuntos
Conotoxinas/toxicidade , Dissulfetos/metabolismo , Canal de Sódio Disparado por Voltagem NAV1.2/metabolismo , Neurônios/metabolismo , Bloqueadores do Canal de Sódio Disparado por Voltagem/toxicidade , Sequência de Aminoácidos , Animais , Sequência de Bases , Cromatografia Líquida de Alta Pressão , Conotoxinas/genética , Conotoxinas/metabolismo , Cisteína/metabolismo , Primers do DNA/genética , DNA Complementar/genética , Dados de Sequência Molecular , Oócitos/metabolismo , Técnicas de Patch-Clamp , Ratos , Análise de Sequência de DNA , Espectrometria de Massas em Tandem , Bloqueadores do Canal de Sódio Disparado por Voltagem/metabolismo
5.
J Biol Chem ; 287(24): 20727-36, 2012 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-22518838

RESUMO

Conantokins are short peptides derived from the venoms of marine cone snails that act as antagonists of the N-methyl-D-aspartate (NMDA) receptor family of excitatory glutamate receptors. These peptides contain γ-carboxyglutamic acid residues typically spaced at i,i+4 and/or i,i+7 intervals, which by chelating divalent cations induce and stabilize helical conformation of the peptide. Introduction of a dicarba bridge (or a staple) can covalently stabilize peptide helicity and improve its pharmacological properties. To test the hypothesis that stapling can effectively replace γ-carboxyglutamic acid residues in stabilizing the helical conformation of conantokins, we designed, synthesized, and characterized several stapled analogs of conantokin G (conG), with varying connectivities in terms of staple length and location along the face of the α-helix. NMR studies confirmed that the ring-closing metathesis reaction yielded a single product with the Z configuration of the olefinic bond. Based on circular dichroism and molecular modeling, the stapled analogs exhibited significantly enhanced helicity compared with the native peptide in a metal-free environment. Stapling i,i+4 was benign with respect to effects on in vitro and in vivo pharmacological properties. One analog, namely conG[11-15,S(i,i+4)S(8)], blocked NR2B-containing NMDA receptors with IC(50) = 0.7 µm and provided significant protection in the 6-Hz psychomotor model of pharmacoresistant epilepsy in mice. Remarkably, unlike native conG, conG[11-15,S(i,i+4)S(8)] produced no behavioral motor toxicity. Our results extend the applications of peptide stapling to helical peptides with extracellular targets and provide a means for engineering conantokins with improved pharmacological properties.


Assuntos
Ácido 1-Carboxiglutâmico/química , Conotoxinas , Epilepsia/tratamento farmacológico , Antagonistas de Aminoácidos Excitatórios , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Ácido 1-Carboxiglutâmico/farmacologia , Animais , Conotoxinas/química , Conotoxinas/farmacologia , Epilepsia/metabolismo , Antagonistas de Aminoácidos Excitatórios/química , Antagonistas de Aminoácidos Excitatórios/farmacologia , Masculino , Camundongos , Ressonância Magnética Nuclear Biomolecular , Estrutura Secundária de Proteína , Receptores de N-Metil-D-Aspartato/metabolismo
6.
Bioorg Med Chem ; 21(1): 303-10, 2013 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-23176753

RESUMO

Hydrocarbon stapling is an effective strategy to stabilize the helical conformation of bioactive peptides. Here we describe application of stapling to anticonvulsant neuropeptides, galanin (GAL) and neuropeptide Y (NPY), that are implicated in modulating seizures in the brain. Dicarba bridges were rationally introduced into minimized analogs of GAL and NPY resulting in increased α-helical content, in vitro metabolic stability and n-octanol/water partitioning coefficient (logD). The stapled analogs retained agonist activities towards their respective receptors and suppressed seizures in a mouse model of epilepsy.


Assuntos
Anticonvulsivantes/química , Anticonvulsivantes/uso terapêutico , Epilepsia/tratamento farmacológico , Galanina/análogos & derivados , Galanina/uso terapêutico , Neuropeptídeo Y/análogos & derivados , Neuropeptídeo Y/uso terapêutico , Sequência de Aminoácidos , Animais , Anticonvulsivantes/metabolismo , Ciclização , Estabilidade de Medicamentos , Galanina/metabolismo , Masculino , Camundongos , Dados de Sequência Molecular , Neuropeptídeo Y/metabolismo , Estabilidade Proteica , Estrutura Secundária de Proteína , Ratos
7.
Biochemistry ; 51(49): 9826-35, 2012 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-23167564

RESUMO

In the preparation of synthetic conotoxins containing multiple disulfide bonds, oxidative folding can produce numerous permutations of disulfide bond connectivities. Establishing the native disulfide connectivities thus presents a significant challenge when the venom-derived peptide is not available, as is increasingly the case when conotoxins are identified from cDNA sequences. Here, we investigate the disulfide connectivity of µ-conotoxin KIIIA, which was predicted originally to have a [C1-C9,C2-C15,C4-C16] disulfide pattern based on homology with closely related µ-conotoxins. The two major isomers of synthetic µ-KIIIA formed during oxidative folding were purified and their disulfide connectivities mapped by direct mass spectrometric collision-induced dissociation fragmentation of the disulfide-bonded polypeptides. Our results show that the major oxidative folding product adopts a [C1-C15,C2-C9,C4-C16] disulfide connectivity, while the minor product adopts a [C1-C16,C2-C9,C4-C15] connectivity. Both of these peptides were potent blockers of Na(V)1.2 (K(d) values of 5 and 230 nM, respectively). The solution structure for µ-KIIIA based on nuclear magnetic resonance data was recalculated with the [C1-C15,C2-C9,C4-C16] disulfide pattern; its structure was very similar to the µ-KIIIA structure calculated with the incorrect [C1-C9,C2-C15,C4-C16] disulfide pattern, with an α-helix spanning residues 7-12. In addition, the major folding isomers of µ-KIIIB, an N-terminally extended isoform of µ-KIIIA identified from its cDNA sequence, were isolated. These folding products had the same disulfide connectivities as µ-KIIIA, and both blocked Na(V)1.2 (K(d) values of 470 and 26 nM, respectively). Our results establish that the preferred disulfide pattern of synthetic µ-KIIIA and µ-KIIIB folded in vitro is 1-5/2-4/3-6 but that other disulfide isomers are also potent sodium channel blockers. These findings raise questions about the disulfide pattern(s) of µ-KIIIA in the venom of Conus kinoshitai; indeed, the presence of multiple disulfide isomers in the venom could provide a means of further expanding the snail's repertoire of active peptides.


Assuntos
Conotoxinas/farmacologia , Dissulfetos/química , Ativação do Canal Iônico , Isomerismo , Canais de Sódio/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Clonagem Molecular , Conotoxinas/química , Conotoxinas/genética , Espectrometria de Massas , Ressonância Magnética Nuclear Biomolecular , Oxirredução
8.
J Pept Sci ; 16(9): 486-95, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20645434

RESUMO

The neuropeptides galanin (GAL), neuropeptide Y (NPY) or neurotensin (NT) exhibit anticonvulsant activities mediated by their respective receptors in the brain. To transform these peptides into potential neurotherapeutics, their systemic bioavailability and metabolic stability must be improved. Our recent studies with GAL analogs suggested that an introduction of lipoamino acids in the context of oligo-Lys residues (lipidization-cationization motif) significantly increases their penetration into the brain, yielding potent antiepileptic compounds. Here, we describe an extension of this strategy to NPY and NT. Rationally designed analogs of NPY and NT containing the lipidization-cationization motif were chemically synthesized and their physicochemical and pharmacological properties were characterized. The analogs NPY-BBB2 and NT-BBB1 exhibited increased serum stability, possessed log D > 1.1, retained high affinities toward their native receptors and produced potent antiseizure activities in animal models of epilepsy following intraperitoneal administration. Our results suggest that the combination of lipidization and cationization may be an effective strategy for improving systemic bioavailability and metabolic stability of various neuroactive peptides.


Assuntos
Anticonvulsivantes/farmacologia , Neuropeptídeo Y/análogos & derivados , Neurotensina/análogos & derivados , Animais , Anticonvulsivantes/síntese química , Barreira Hematoencefálica/efeitos dos fármacos , Cátions/química , Epilepsia/tratamento farmacológico , Lipídeos/química , Neuropeptídeo Y/síntese química , Neuropeptídeo Y/farmacologia , Neurotensina/síntese química , Neurotensina/farmacologia , Ratos , Receptores de Neuropeptídeo Y/metabolismo , Receptores de Neurotensina/metabolismo
9.
Toxicon ; 53(1): 90-8, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18950653

RESUMO

Described herein is a general approach to identify novel compounds using the biodiversity of a megadiverse group of animals; specifically, the phylogenetic lineage of the venomous gastropods that belong to the genus Conus ("cone snails"). Cone snail biodiversity was exploited to identify three new mu-conotoxins, BuIIIA, BuIIIB and BuIIIC, encoded by the fish-hunting species Conus bullatus. BuIIIA, BuIIIB and BuIIIC are strikingly divergent in their amino acid composition compared to previous mu-conotoxins known to target the voltage-gated Na channel skeletal muscle subtype Na(v)1.4. Our preliminary results indicate that BuIIIB and BuIIIC are potent inhibitors of Na(v)1.4 (average block approximately 96%, at a 1muM concentration of peptide), displaying a very slow off-rate not seen in previously characterized mu-conotoxins that block Na(v)1.4. In addition, the three new C. bullatus mu-conopeptides help to define a new branch of the M-superfamily of conotoxins, namely M-5. The exogene strategy used to discover these Na channel-inhibiting peptides was based on both understanding the phylogeny of Conus, as well as the molecular genetics of venom mu-conotoxin peptides previously shown to generally target voltage-gated Na channels. The discovery of BuIIIA, BuIIIB and BuIIIC Na channel blockers expands the diversity of ligands useful in determining the structure-activity relationship of voltage-gated sodium channels.


Assuntos
Biodiversidade , Conotoxinas/química , Caramujo Conus/genética , Caramujo Conus/fisiologia , Bloqueadores dos Canais de Sódio/química , Aminoácido N-Acetiltransferase , Animais , Sequência de Bases , Clonagem Molecular , Conotoxinas/genética , Conotoxinas/metabolismo , DNA Complementar , Venenos de Moluscos/química , Oócitos , Filogenia , Bloqueadores dos Canais de Sódio/farmacologia , Canais de Sódio/metabolismo , Xenopus
10.
Chem Biol ; 14(4): 399-407, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17462575

RESUMO

Disulfide-rich neurotoxins from venomous animals continue to provide compounds with therapeutic potential. Minimizing neurotoxins often results in removal of disulfide bridges or critical amino acids. To address this drug-design challenge, we explored the concept of disulfide-rich scaffolds consisting of isostere polymers and peptidic pharmacophores. Flexible spacers, such as amino-3-oxapentanoic or 6-aminohexanoic acids, were used to replace conformationally constrained parts of a three-disulfide-bridged conotoxin, SIIIA. The peptide-polymer hybrids, polytides, were designed based on cladistic identification of nonconserved loci in related peptides. After oxidative folding, the polytides appeared to be better inhibitors of sodium currents in dorsal root ganglia and sciatic nerves in mice. Moreover, the polytides appeared to be significantly more potent and longer-lasting analgesics in the inflammatory pain model in mice, when compared to SIIIA. The resulting polytides provide a promising strategy for transforming disulfide-rich peptides into therapeutics.


Assuntos
Analgésicos não Narcóticos/síntese química , Conotoxinas/síntese química , Desenho de Fármacos , Peptídeos/síntese química , Sequência de Aminoácidos , Analgésicos não Narcóticos/química , Analgésicos não Narcóticos/farmacologia , Animais , Conotoxinas/química , Conotoxinas/farmacologia , Gânglios Espinais/efeitos dos fármacos , Gânglios Espinais/metabolismo , Camundongos , Camundongos Endogâmicos , Dados de Sequência Molecular , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Dor/tratamento farmacológico , Medição da Dor , Peptídeos/química , Peptídeos/farmacologia , Nervo Isquiático/efeitos dos fármacos , Nervo Isquiático/metabolismo , Bloqueadores dos Canais de Sódio/síntese química , Bloqueadores dos Canais de Sódio/química , Bloqueadores dos Canais de Sódio/farmacologia
11.
Prehosp Disaster Med ; 23(1): 63-7; discussion 68-9, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18491664

RESUMO

OBJECTIVES: The objectives of the study were to develop and evaluate an "all-hazards" hospital disaster preparedness training course that utilizes a combination of classroom lectures, skills sessions, tabletop sessions, and disaster exercises to teach the principles of hospital disaster preparedness to hospital-based employees. METHODS: Participants attended a two-day, 16-hour course, entitled Hospital Disaster Life Support (HDLS). The course was designed to address seven core competencies of disaster training for healthcare workers. Specific disaster situations addressed during HDLS included: (1) biological; (2) conventional; (3) radiological; and (4) chemical mass-casualty incidents. The primary goal of HDLS was not only to teach patient care for a disaster, but more importantly, to teach hospital personnel how to manage the disaster itself. Knowledge gained from the HDLS course was assessed by pre- and post-test evaluations. Additionally, participants completed a course evaluation survey at the conclusion of HDLS to assess their attitudes about the course. RESULTS: Participants included 11 physicians, 40 nurses, 23 administrators/directors, and 10 other personnel (n = 84). The average score on the pre-test was 69.1 +/- 12.8 for all positions, and the post-test score was 89.5 +/- 6.7, an improvement of 20.4 points (p < 0.0001, 17.2-23.5). Participants felt HDLS was educational (4.2/5), relevant (4.3/5) and organized (4.3/5). CONCLUSIONS: Identifying an effective means of teaching hospital disaster preparedness to hospital-based employees is an important task. However, the optimal strategy for implementing such education still is under debate. The HDLS course was designed to utilize multiple teaching modalities to train hospital-based employees on the principles of disaster preparedness. Participants of HDLS showed an increase in knowledge gained and reported high satisfaction from their experiences at HDLS. These results suggest that HDLS is an effective way to train hospital-based employees in the area of disaster preparedness.


Assuntos
Planejamento em Desastres/organização & administração , Serviço Hospitalar de Emergência/organização & administração , Planejamento Hospitalar , Incidentes com Feridos em Massa , Recursos Humanos em Hospital/educação , Socorro em Desastres/organização & administração , Ensino , Coleta de Dados , District of Columbia , Escolaridade , Humanos , Cuidados para Prolongar a Vida , Modelos Educacionais , Simulação de Paciente , Desenvolvimento de Programas , Avaliação de Programas e Projetos de Saúde , Estados Unidos
12.
Simul Healthc ; 12(6): 385-392, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29076970

RESUMO

INTRODUCTION: "Transitions to residency" programs are designed to maximize quality and safety of patient care, as medical students become residents. However, best instructional or readiness assessment practices are not yet established. We sought to study the impact of a screen-based interactive curriculum designed to prepare interns to address common clinical coverage issues (WISE OnCall) on the clinical skills demonstrated in simulation and hypothesize that performance would improve after completing the module. METHODS: Senior medical students were recruited to participate in this single group prestudy/poststudy. Students responded to a call from a standardized nurse (SN) and assessed a standardized patient (SP) with low urine output, interacted with a 45-minute WISE OnCall module on the assessment and management of oliguria, and then evaluated a different SP with low urine output of a different underlying cause. Standardized patients assessed clinical skills with a 37-item, behaviorally anchored checklist measuring clinical skills (intraclass correlation coefficient [ICC], 0.55-0.81). Standardized nurses rated care quality and safety and collaboration and interprofessional communication using a 33-item literature-based, anchored checklist (ICC, 0.47-0.52). Standardized patient and SN ratings of the same student performance were correlated (r, 0.37-0.62; P < 0.01). Physicians assessed clinical reasoning quality based on the students' patient encounter note (ICC, 0.55-0.68), ratings that did not correlate with SP and SN ratings. We compared pre-post clinical skills performance and clinical reasoning. Fifty-two medical students (31%) completed this institutional review board -approved study. RESULTS: Performance as measured by the SPs, SNs, and the postencounter note all showed improvement with mostly moderate to large effect sizes (range of Cohen's d, 0.30-1.88; P < 0.05) after completion of the online module. Unexpectedly, professionalism as rated by the SP was poorer after the module (Cohen's d, -0.93; P = 0.000). DISCUSSION: A brief computer-based educational intervention significantly improved graduating medical students' clinical skills needed to be ready for residency.


Assuntos
Competência Clínica , Instrução por Computador/métodos , Educação de Graduação em Medicina/métodos , Tomada de Decisão Clínica , Comunicação , Comportamento Cooperativo , Currículo , Humanos , Relações Interprofissionais , Oligúria/diagnóstico , Oligúria/terapia , Relações Médico-Paciente , Qualidade da Assistência à Saúde
13.
West J Emerg Med ; 18(1): 35-42, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28116006

RESUMO

INTRODUCTION: Medical schools in the United States are encouraged to prepare and certify the entrustment of medical students to perform 13 core entrustable professional activities (EPAs) prior to graduation. Entrustment is defined as the informed belief that the learner is qualified to autonomously perform specific patient-care activities. Core EPA-10 is the entrustment of a graduate to care for the emergent patient. The purpose of this project was to design a realistic performance assessment method for evaluating fourth-year medical students on EPA-10. METHODS: First, we wrote five emergent patient case-scenarios that a medical trainee would likely confront in an acute care setting. Furthermore, we developed high-fidelity simulations to realistically portray these patient case scenarios. Finally, we designed a performance assessment instrument to evaluate the medical student's performance on executing critical actions related to EPA-10 competencies. Critical actions included the following: triage skills, mustering the medical team, identifying causes of patient decompensation, and initiating care. Up to four students were involved with each case scenario; however, only the team leader was evaluated using the assessment instruments developed for each case. RESULTS: A total of 114 students participated in the EPA-10 assessment during their final year of medical school. Most students demonstrated competence in recognizing unstable vital signs (97%), engaging the team (93%), and making appropriate dispositions (92%). Almost 87% of the students were rated as having reached entrustment to manage the care of an emergent patient (99 of 114). Inter-rater reliability varied by case scenario, ranging from moderate to near-perfect agreement. Three of five case-scenario assessment instruments contained items that were internally consistent at measuring student performance. Additionally, the individual item scores for these case scenarios were highly correlated with the global entrustment decision. CONCLUSION: High-fidelity simulation showed good potential for effective assessment of medical student entrustment of caring for the emergent patient. Preliminary evidence from this pilot project suggests content validity of most cases and associated checklist items. The assessments also demonstrated moderately strong faculty inter-rater reliability.


Assuntos
Competência Clínica/normas , Educação Baseada em Competências/métodos , Avaliação Educacional/métodos , Avaliação de Programas e Projetos de Saúde/normas , Educação de Graduação em Medicina , Humanos , Projetos Piloto , Estudantes de Medicina , Estados Unidos
14.
Protein Pept Lett ; 13(1): 67-70, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16454672

RESUMO

We tested two alternative oxidation strategies to produce conotoxins alpha-GI and micro-PIIIA. The peptides were either reversibly immobilized on a solid support and then oxidized, or the immobilized disulfide reagent (CLEAR-OX(trade mark)) was used to oxidize the peptides. Both strategies appeared more efficient at higher peptide concentrations, consistent with pseudo-dilution effects.


Assuntos
Conotoxinas/química , Dobramento de Proteína , Sequência de Aminoácidos , Dissulfetos/química , Dados de Sequência Molecular , Oxirredução
15.
FEBS J ; 272(7): 1727-38, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15794759

RESUMO

Conotoxins are short, disulfide-rich peptide neurotoxins produced in the venom of predatory marine cone snails. It is generally accepted that an estimated 100,000 unique conotoxins fall into only a handful of structural groups, based on their disulfide bridging frameworks. This unique molecular diversity poses a protein folding problem of relationships between hypervariability of amino acid sequences and mechanism(s) of oxidative folding. In this study, we present a comparative analysis of the folding properties of four conotoxins sharing an identical pattern of cysteine residues forming three disulfide bridges, but otherwise differing significantly in their primary amino acid sequence. Oxidative folding properties of M-superfamily conotoxins GIIIA, PIIIA, SmIIIA and RIIIK varied with respect to kinetics and thermodynamics. Based on rates for establishing the steady-state distribution of the folding species, two distinct folding mechanisms could be distinguished: first, rapid-collapse folding characterized by very fast, but low-yield accumulation of the correctly folded form; and second, slow-rearrangement folding resulting in higher accumulation of the properly folded form via the reshuffling of disulfide bonds within folding intermediates. Effects of changing the folding conditions indicated that the rapid-collapse and the slow-rearrangement mechanisms were mainly determined by either repulsive electrostatic or productive noncovalent interactions, respectively. The differences in folding kinetics for these two mechanisms were minimized in the presence of protein disulfide isomerase. Taken together, folding properties of conotoxins from the M-superfamily presented in this work and from the O-superfamily published previously suggest that conotoxin sequence diversity is also reflected in their folding properties, and that sequence information rather than a cysteine pattern determines the in vitro folding mechanisms of conotoxins.


Assuntos
Conotoxinas/metabolismo , Cistina/metabolismo , Moluscos/metabolismo , Animais , Conotoxinas/genética , Cistina/genética , Moluscos/genética , Oxirredução , Dobramento de Proteína
16.
Future Med Chem ; 6(15): 1677-98, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25406007

RESUMO

µ-Conotoxins block voltage-gated sodium channels (VGSCs) and compete with tetrodotoxin for binding to the sodium conductance pore. Early efforts identified µ-conotoxins that preferentially blocked the skeletal muscle subtype (NaV1.4). However, the last decade witnessed a significant increase in the number of µ-conotoxins and the range of VGSC subtypes inhibited (NaV1.2, NaV1.3 or NaV1.7). Twenty µ-conotoxin sequences have been identified to date and structure-activity relationship studies of several of these identified key residues responsible for interactions with VGSC subtypes. Efforts to engineer-in subtype specificity are driven by in vivo analgesic and neuromuscular blocking activities. This review summarizes structural and pharmacological studies of µ-conotoxins, which show promise for development of selective blockers of NaV1.2, and perhaps also NaV1.1,1.3 or 1.7.


Assuntos
Analgésicos/química , Conotoxinas/química , Bloqueadores dos Canais de Sódio/química , Canais de Sódio Disparados por Voltagem/química , Analgésicos/metabolismo , Analgésicos/uso terapêutico , Animais , Conotoxinas/metabolismo , Conotoxinas/uso terapêutico , Caramujo Conus/metabolismo , Dor/tratamento farmacológico , Dor/patologia , Isoformas de Proteínas/antagonistas & inibidores , Isoformas de Proteínas/metabolismo , Estrutura Terciária de Proteína , Bloqueadores dos Canais de Sódio/metabolismo , Bloqueadores dos Canais de Sódio/uso terapêutico , Relação Estrutura-Atividade , Canais de Sódio Disparados por Voltagem/metabolismo
17.
FEBS J ; 281(13): 2885-98, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24814369

RESUMO

Inhibitors of the α-subunit of the voltage-gated sodium channel subtype 1.3 (NaV 1.3) are of interest as pharmacological tools for the study of neuropathic pain associated with spinal cord injury and have potential therapeutic applications. The recently described µ-conotoxin BuIIIB (µ-BuIIIB) from Conus bullatus was shown to block NaV 1.3 with submicromolar potency (Kd = 0.2 µm), making it one of the most potent peptidic inhibitors of this subtype described to date. However, oxidative folding of µ-BuIIIB results in numerous folding isoforms, making it difficult to obtain sufficient quantities of the active form of the peptide for detailed structure-activity studies. In the present study, we report the synthesis and characterization of µ-BuIIIB analogs incorporating a disulfide-deficient, diselenide-containing scaffold designed to simplify synthesis and facilitate structure-activity studies directed at identifying amino acid residues involved in NaV 1.3 blockade. Our results indicate that, similar to other µ-conotoxins, the C-terminal residues (Trp16, Arg18 and His20) are most crucial for NaV 1 blockade. At the N-terminus, replacement of Glu3 by Ala resulted in an analog with an increased potency for NaV 1.3 (Kd = 0.07 µm), implicating this position as a potential site for modification for increased potency and/or selectivity. Further examination of this position showed that increased negative charge, through γ-carboxyglutamate replacement, decreased potency (Kd = 0.33 µm), whereas replacement with positively-charged 2,4-diamonobutyric acid increased potency (Kd = 0.036 µm). These results provide a foundation for the design and synthesis of µ-BuIIIB-based analogs with increased potency against NaV 1.3.


Assuntos
Analgésicos/síntese química , Conotoxinas/síntese química , Canal de Sódio Disparado por Voltagem NAV1.3/metabolismo , Selenocisteína/química , Bloqueadores do Canal de Sódio Disparado por Voltagem/síntese química , Sequência de Aminoácidos , Substituição de Aminoácidos , Analgésicos/química , Analgésicos/farmacologia , Animais , Células Cultivadas , Conotoxinas/química , Conotoxinas/farmacologia , Cistina/química , Espectroscopia de Ressonância Magnética , Potenciais da Membrana , Dados de Sequência Molecular , Estrutura Secundária de Proteína , Relação Estrutura-Atividade , Bloqueadores do Canal de Sódio Disparado por Voltagem/química , Bloqueadores do Canal de Sódio Disparado por Voltagem/farmacologia , Xenopus laevis
18.
Emerg Med Pract ; 13(7): 1-17; quiz 18, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22164398

RESUMO

The acute treatment of kidney stones (urolithiasis) addresses pain management and focuses on the effects of the morbidity associated with an obstructed renal system. Minimal fluid intake, resulting in decreased urine production and a high concentration of stone-forming salts, is a leading factor in renal calculi development. Radio-opaque calcareous stones account for 70% to 75% of renal calculi. Microscopic hematuria in the presence of acute flank pain is suggestive of renal colic, but the absence of red blood cells does not exclude urolithiasis. Furthermore, many inflammatory and infectious conditions cause hematuria, demonstrating the low specificity of urinalysis testing. The diagnostic modality of choice is a noncontrast computed tomography (CT); ultrasonography s preferred in pregnant patients and children. Combining opioids with non-steroidal anti-inflammatory drugs (NSAIDs) is the optimal evidence-based regimen to treat severe symptoms. Rapid intravenous (IV) hydration has not shown a benefit. Potentially life-threatening diagnoses including abdominal aortic aneurysm, ovarian torsion, and appendicitis may mimic renal colic and must be ruled out.


Assuntos
Serviço Hospitalar de Emergência/organização & administração , Tratamento de Emergência , Cálculos Renais/diagnóstico , Cálculos Renais/tratamento farmacológico , Algoritmos , Anti-Inflamatórios não Esteroides/uso terapêutico , Diagnóstico Diferencial , Diagnóstico por Imagem , Feminino , Humanos , Masculino , Manejo da Dor , Gravidez , Complicações na Gravidez/diagnóstico , Complicações na Gravidez/tratamento farmacológico , Fatores de Risco , Gestão de Riscos
19.
ACS Chem Neurosci ; 2(1): 51-6, 2011 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-22826747

RESUMO

Anticonvulsant neuropeptides play an important role in controlling neuronal excitability that leads to pain or seizures. Based on overlapping inhibitory mechanisms, many anticonvulsant compounds have been found to exhibit both analgesic and antiepileptic activities. An analgesic neuropeptide W (NPW) targets recently deorphanized G-protein coupled receptors. Here, we tested the hypothesis that the analgesic activity of NPW may lead to the discovery of its antiepileptic properties. Indeed, direct administration of NPW into the brain potently reduced seizures in mice. To confirm this discovery, we rationally designed, synthesized, and characterized NPW analogues that exhibited anticonvulsant activities following systemic administration. Our results suggest that the combination of neuropeptide repositioning and engineering NPW analogues that penetrate the blood-brain barrier could provide new drug leads, not only for the treatment of epilepsy and pain but also for studying effects of this peptide on regulating feeding and energy metabolism coupled to leptin levels in the brain.


Assuntos
Analgésicos/uso terapêutico , Encéfalo/efeitos dos fármacos , Neuropeptídeos/uso terapêutico , Engenharia de Proteínas/métodos , Convulsões/tratamento farmacológico , Sequência de Aminoácidos , Analgésicos/química , Animais , Anticonvulsivantes/química , Anticonvulsivantes/farmacologia , Anticonvulsivantes/uso terapêutico , Encéfalo/fisiologia , Humanos , Dados de Sequência Molecular , Neuropeptídeos/farmacologia , Convulsões/fisiopatologia
20.
Cyberpsychol Behav Soc Netw ; 13(2): 217-24, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20528282

RESUMO

Simulation- and video game-based role-playing techniques have been proven effective in changing behavior and enhancing positive decision making in a variety of professional settings, including education, the military, and health care. Although the need for developing assessment frameworks for learning outcomes has been clearly defined, there is a significant gap between the variety of existing multimedia-based instruction and technology-mediated learning systems and the number of reliable assessment algorithms. This study, based on a mixed methodology research design, aims to develop an embedded assessment algorithm, a Knowledge Assessment Module (NOTE), to capture both user interaction with the educational tool and knowledge gained from the training. The study is regarded as the first step in developing an assessment framework for a multimedia educational tool for health care professionals, Anatomy of Care (AOC), that utilizes Virtual Experience Immersive Learning Simulation (VEILS) technology. Ninety health care personnel of various backgrounds took part in online AOC training, choosing from five possible scenarios presenting difficult situations of everyday care. The results suggest that although the simulation-based training tool demonstrated partial effectiveness in improving learners' decision-making capacity, a differential learner-oriented approach might be more effective and capable of synchronizing educational efforts with identifiable relevant individual factors such as sociobehavioral profile and professional background.


Assuntos
Educação Continuada/métodos , Pessoal de Saúde/educação , Desempenho de Papéis , Adulto , Idoso , Simulação por Computador , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
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