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1.
Curr Sports Med Rep ; 22(9): 307-312, 2023 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-37678349

RESUMEN

ABSTRACT: Frozen shoulder is a common condition that causes pain and restriction of movement of the shoulder unrelated to secondary causes. It has three classic phases (freezing, frozen, and thawing), and is resolved in most cases within 1 to 2 years. Diagnosis is clinical based on global motion restriction and pain. Imaging plays an ancillary role to narrow the differential diagnosis. Physical therapy, nonsteroidal anti-inflammatories, and injection therapies are standard treatments, although none have been shown to alter the long-term course of the condition. Ultrasound guidance is recommended for injection-based therapy, although not required. Further study should focus on long-term outcomes and treatments that significantly alter the natural course of the disease.


Asunto(s)
Bursitis , Humanos , Diagnóstico Diferencial , Bursitis/diagnóstico , Bursitis/terapia , Antiinflamatorios no Esteroideos/uso terapéutico , Movimiento , Dolor
2.
J Environ Manage ; 313: 115004, 2022 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-35405544

RESUMEN

Stormwater management problems are expanding as urbanization continues and precipitation patterns are increasingly extreme. Urban soils are often more disturbed and compacted than non-urban soils, therefore, rainfall run-off estimates based on models designed for non-urban soils may not be accurate due to altered soil infiltration rates. Our objective was to quantify soil infiltration rates across an urban watershed and compare them to estimates from rainfall-runoff models commonly used in stormwater management (Horton and Green-Ampt) as well as an alternate, random-forest model created using available geospatial data. We measured infiltration rates and collected data on soil properties (texture, bulk density) and context (land use, ground cover, time since development) at 89 points across the 102 ha Walnut Creek watershed in Raleigh, North Carolina (USA). Forest land covers and forest ground covers (leaf litter) had the highest infiltration capacities; however, all of our measurements indicate that urban soils in the Walnut Creek watershed are able to absorb most precipitation events and are likely capable of infiltrating additional urban stormwater runoff. Comparisons between observations and the rainfall-runoff model estimates reveal that both underestimated urban soil infiltration rates. Despite higher than expected urban soil infiltration capacity, stormwater management remains a challenge in this urban watershed. Therefore, to reduce stormwater runoff from impervious surfaces through soil infiltration, impervious surfaces should be disconnected, especially adjacent to new development, and urban forests should be conserved. Further, because our random forest model more accurately captured watershed infiltration rates than the rainfall-runoff models, we propose this type of machine learning approach as an alternative method for informing stormwater management and prioritizing areas for impervious disconnection.


Asunto(s)
Lluvia , Suelo , North Carolina , Urbanización , Movimientos del Agua
3.
Blood ; 128(15): 1969-1978, 2016 10 13.
Artículo en Inglés | MEDLINE | ID: mdl-27561317

RESUMEN

Coagulation transglutaminase factor XIII (FXIII) exists in circulation as heterotetrameric proenzyme FXIII-A2B2 Effectively all FXIII-A2B2 circulates bound to fibrinogen, and excess FXIII-B2 circulates in plasma. The motifs that mediate interaction of FXIII-A2B2 with fibrinogen have been elusive. We recently detected reduced binding of FXIII-A2B2 to murine fibrinogen that has γ-chain residues 390-396 mutated to alanines (Fibγ390-396A). Here, we evaluated binding features using human components, including recombinant fibrinogen variants, FXIII-A2B2, and isolated FXIII-A2 and -B2 homodimers. FXIII-A2B2 coprecipitated with wild-type (γA/γA), alternatively-spliced (γ'/γ'), and αC-truncated (Aα251) fibrinogens, whereas coprecipitation with human Fibγ390-396A was reduced by 75% (P <0001). Surface plasmon resonance showed γA/γA, γ'/γ', and Aα251 fibrinogens bound FXIII-A2B2 with high affinity (nanomolar); however, Fibγ390-396A did not bind FXIII-A2B2 These data indicate fibrinogen residues γ390-396 comprise the major binding motif for FXIII-A2B2 Compared with γA/γA clots, FXIII-A2B2 activation peptide release was 2.7-fold slower in Fibγ390-396A clots (P < .02). Conversely, activation of recombinant FXIII-A2 (lacking FXIII-B2) was similar in γA/γA and Fibγ390-396A clots, suggesting fibrinogen residues γ390-396 accelerate FXIII-A2B2 activation in a FXIII-B2-dependent mechanism. Recombinant FXIII-B2 bound γA/γA, γ'/γ', and Aα251 with similar affinities as FXIII-A2B2, but did not bind or coprecipitate with Fibγ390-396A FXIII-B2 also coprecipitated with fibrinogen from FXIII-A-deficient mouse and human plasmas. Collectively, these data indicate that FXIII-A2B2 binds fibrinogen residues γ390-396 via the B subunits, and that excess plasma FXIII-B2 is not free, but rather circulates bound to fibrinogen. These findings provide insight into assembly of the fibrinogen/FXIII-A2B2 complex in both physiologic and therapeutic situations.


Asunto(s)
Precursores Enzimáticos , Factor XIII , Fibronectinas , Secuencias de Aminoácidos , Animales , Precursores Enzimáticos/química , Precursores Enzimáticos/genética , Precursores Enzimáticos/metabolismo , Factor XIII/química , Factor XIII/genética , Factor XIII/metabolismo , Fibronectinas/química , Fibronectinas/genética , Fibronectinas/metabolismo , Humanos , Ratones , Ratones Noqueados , Unión Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Resonancia por Plasmón de Superficie
4.
Am J Obstet Gynecol ; 219(2): 174.e1-174.e8, 2018 08.
Artículo en Inglés | MEDLINE | ID: mdl-29792853

RESUMEN

BACKGROUND: Women with a gynecologic cancer tend to be older, obese, and postmenopausal, characteristics that are associated with an increased risk for obstructive sleep apnea. However, there is limited investigation regarding the condition's prevalence in this population or its impact on postoperative outcomes. In other surgical populations, patients with obstructive sleep apnea have been observed to be at increased risk for adverse postoperative events. OBJECTIVE: We sought to estimate the prevalence of obstructive sleep apnea among gynecologic oncology patients undergoing elective surgery and to investigate for a relationship between obstructive sleep apnea and postoperative outcomes. STUDY DESIGN: Patients referred to an academic gynecologic oncology practice were approached for enrollment in this prospective, observational study. Patients were considered eligible for study enrollment if they were scheduled for a nonemergent inpatient surgery and could provide informed consent. Enrolled patients were evaluated for a preexisting diagnosis of obstructive sleep apnea. Those without a prior diagnosis were screened using the validated, 4-item STOP questionnaire (ie, Snore loudly, daytime Tiredness, Observed apnea, elevated blood Pressure). All patients who screened positive for obstructive sleep apnea were referred for polysomnography. The primary outcome was the prevalence of women with obstructive sleep apnea or those who screened at high risk for the condition. Secondary outcomes examined the correlation between body mass index (kg/m2) with obstructive sleep apnea and assessed for a relationship between obstructive sleep apnea and postoperative outcomes. RESULTS: Over a 22-month accrual period, 383 eligible patients were consecutively approached to participate in the study. A cohort of 260 patients were enrolled. A total of 33/260 patients (13%) were identified as having a previous diagnosis of obstructive sleep apnea. An additional 66/260 (25%) screened at risk for the condition using the STOP questionnaire. Of the patients who screened positive, 8/66 (12%) completed polysomnography, all of whom (8/8 [100%]) were found to have obstructive sleep apnea. The prevalence of previously diagnosed obstructive sleep apnea or screening at risk for the condition increased as body mass index increased (P < .001). Women with untreated obstructive sleep apnea and those who screened at risk for the condition were found to have an increased risk for postoperative hypoxemia (odds ratio, 3.5; 95% confidence interval, 1.8-4.7; P = .011) and delayed return of bowel function (odds ratio, 2.1; 95% confidence interval, 1.3-4.5; P = .009). CONCLUSION: The prevalence of obstructive sleep apnea or screening at risk for the condition is high among women presenting for surgery with a gynecologic oncologist. Providers should consider evaluating a patient's risk for obstructive sleep apnea in the preoperative setting, especially when risk factors for the condition are present.


Asunto(s)
Neoplasias de los Genitales Femeninos/cirugía , Hipoxia/epidemiología , Complicaciones Posoperatorias/epidemiología , Apnea Obstructiva del Sueño/epidemiología , Adulto , Anciano , Anciano de 80 o más Años , Índice de Masa Corporal , Femenino , Neoplasias de los Genitales Femeninos/epidemiología , Procedimientos Quirúrgicos Ginecológicos , Humanos , Hipertensión , Estudios Longitudinales , Tamizaje Masivo , Persona de Mediana Edad , Oportunidad Relativa , Polisomnografía , Cuidados Preoperatorios/métodos , Prevalencia , Estudios Prospectivos , Apnea Obstructiva del Sueño/diagnóstico , Somnolencia , Ronquido , Adulto Joven
5.
Biomacromolecules ; 19(8): 3445-3455, 2018 08 13.
Artículo en Inglés | MEDLINE | ID: mdl-30001123

RESUMEN

Peptide-polymer hybrids combine the hierarchy of biological species with synthetic concepts to achieve control over molecular design and material properties. By further incorporating covalent cross-links, the enhancement of molecular complexity is achieved, allowing for both a physical and covalent network. In this work, the structure and function of poly(ethylene glycol) (PEG)-network hybrids are tuned by varying peptide block length and overall peptide content. Here the impact of poly(ε-carbobenzyloxy-l-lysine) (PZLY) units on block interactions and mechanics is explored by probing secondary structure, PEG crystallinity, and hierarchical organization. The incorporation of PZLY reveals a mixture of α-helices and ß-sheets at smaller repeat lengths ( n = 5) and selective α-helix formation at a higher peptide molecular weight ( n = 20). Secondary structure variations tailored the solid-state film hierarchy, whereby nanoscale fibers and microscale spherulites varied in size depending on the amount of α-helices and ß-sheets. This long-range ordering influenced mechanical properties, resulting in a decrease in elongation-at-break (from 400 to 20%) with increasing spherulite diameter. Furthermore, the reduction in soft segment crystallinity with the addition of PZLY resulted in a decrease in moduli. It was determined that, by controlling PZLY content, a balance of physical associations and self-assembly is obtained, leading to tunable PEG crystallinity, spherulite formation, and mechanics.


Asunto(s)
Polilisina/análogos & derivados , Polímeros/química , Cristalización , Fenómenos Mecánicos , Polietilenglicoles/química , Conformación Proteica en Hélice alfa , Conformación Proteica en Lámina beta
6.
Bioconjug Chem ; 28(5): 1325-1339, 2017 05 17.
Artículo en Inglés | MEDLINE | ID: mdl-28471638

RESUMEN

The repair and regeneration of the body's tissue using polymeric materials remains a main focus of biomaterials research. While hydrogels and elastomers have shown biocompatibility and high extensibility, they lack the required toughness to host proliferating cells. As the need for robust polymeric scaffolds grows, new technologies must emerge to meet the stringent physical and biological needs of proliferating cells. To this end, the utilization of self-assembling motifs allows for the construction of versatile networks in which cells can grow. In this review, we discuss emerging techniques that harness the assembling capabilities of synthetic supramolecular and natural peptide motifs to construct mechanically robust elastomers and hydrogel scaffolds. In particular, we focus on how the design and structure impact their mechanical properties and interaction with the cellular environment.


Asunto(s)
Hidrogeles/química , Fragmentos de Péptidos/química , Polímeros/química , Ingeniería de Tejidos , Andamios del Tejido , Animales , Humanos
7.
J Physiol ; 594(4): 883-94, 2016 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-26553530

RESUMEN

KEY POINTS: Using whole-cell clamp methods, we characterized the temporal coding in each type of OFF bipolar cell. We found that type 2 and 3a cells are transient, type 1 and 4 cells are sustained, and type 3b cells are intermediate. The light-evoked excitatory postsynaptic potentials in some types were rectified, suggesting that they provide inputs to the non-linear ganglion cells. Visual signalling from the photoreceptors was mediated exclusively through the kainate receptors in the transient OFF bipolar cells, whereas both kainate and AMPA receptors contributed in the other cells. This study demonstrates, for the first time, that parallel visual encoding starts at the OFF bipolar cells in a type-specific manner. ABSTRACT: The retina is the entrance to the visual system, which receives various kinds of image signals and forms multiple encoding pathways. The second-order retinal neurons, the bipolar cells, are thought to initiate multiple neural streams by encoding various visual signals in different types of cells. However, the functions of each bipolar cell type have not been fully understood. We investigated whether OFF bipolar cells encode visual signals in a type-dependent manner. We recorded the changes in the bipolar cell voltage in response to two input functions: step and sinusoidal light stimuli. Type 1 and 4 OFF bipolar cells were sustained cells and responded to sinusoidal stimuli over a broad range of frequencies. Type 2 and 3a cells were transient and exhibited band-pass filtering. Type 3b cells were in the middle of these two groups. The distinct temporal responses might be attributed to different types of glutamate receptors. We examined the AMPA and kainate glutamate receptor composition in each bipolar cell type. The light responses in the transient OFF bipolar cells were exclusively mediated by kainate receptors. Although the kainate receptors mediated the light responses in the sustained cells, the AMPA receptors also mediated a portion of the responses in sustained cells. Furthermore, we found that some types of cells were rectified more than other types. Taken together, we found that the OFF bipolar cells encode diverse temporal image signals in a type-dependent manner, confirming that each type of OFF bipolar cell initiates diverse temporal visual processing in parallel.


Asunto(s)
Receptores AMPA/metabolismo , Receptores de Ácido Kaínico/metabolismo , Células Bipolares de la Retina/metabolismo , Animales , Ratones , Ratones Endogámicos C57BL , Estimulación Luminosa , Receptores AMPA/genética , Receptores de Ácido Kaínico/genética , Células Bipolares de la Retina/fisiología , Potenciales Sinápticos
8.
Exp Appl Acarol ; 68(4): 509-15, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26704261

RESUMEN

Varroa destructor Anderson & Trueman (Varroa) is a damaging pest of the Western honey bee, Apis mellifera, in North America, Europe, and Asia. However, Varroa infestations have not produced equivalent colony losses of African subspecies of honey bee throughout Africa and parts of the Americas. We surveyed the Varroa infestation rates (number of Varroa per 100 adult honey bees) in colonies of A. m. scutellata, A. m. capensis, and hybrids of the two subspecies throughout the Republic of South Africa in the fall of 2014. We found that A. m. scutellata colonies had significantly higher Varroa infestations than did A. m. capensis colonies. Furthermore, hybridized colonies of the two subspecies had Varroa infestations intermediate to those of A. m. scutellata and A. m. capensis. This is the first documentation of a clear difference in Varroa infestation rates of A. m. scutellata, A. m. capensis, and hybridized colonies in South Africa. Furthermore, our data confirm that Varroa populations in A. m. scutellata colonies are within the range of populations that are damaging to European honey bees.


Asunto(s)
Abejas/parasitología , Varroidae/fisiología , Animales , Apicultura , Estaciones del Año , Sudáfrica , Especificidad de la Especie
9.
J Vis Exp ; (210)2024 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-39248531

RESUMEN

Improving understanding of the basic biology and ecology of many insect pollinators, particularly specialist or rare taxa, is a priority for many researchers. As such, there is often a need to temporarily confine field-collected organisms in a non-injurious manner in order to gain information or support additional studies. This protocol represents a thoroughly tested, quick, and inexpensive field method for safely handling bees of conservation concern that can easily be tailored toward specific project needs, including organism identification, pollen removal, marking, and/or collection of non-lethal tissue samples for genetic analysis. This methodology can serve as an additional option in the researcher's toolbox to use when certain scenarios arise. It is anticipated that this methodology can be adapted for use with other insect species as well as used by individuals of varying experience and skill levels. It can be of great value to researchers studying specialist bees or conducting host-specific studies. The data collection made possible by this protocol will be invaluable to help researchers address critical data gaps for many pollinator species, plant-pollinator network structures, and pollinator conservation and management initiatives.


Asunto(s)
Polinización , Abejas/fisiología , Animales , Entomología/métodos
10.
Chem Commun (Camb) ; 60(32): 4346-4349, 2024 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-38545873

RESUMEN

We present soft-template encapsulation of salt hydrate phase change materials (PCMs) using modified silica particles to both stabilize emulsions and serve as initiators for organocatalyzed photoredox ATRP. The resulting core-shell structures have high core loading and are robust to thermal cycling. Critically, this strategy eliminates the need for a reagent in the core phase, thus preserving purity, and offers the ability to tailor shell composition for desired applications.

11.
Neuropharmacology ; 252: 109949, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38636726

RESUMEN

Psychedelic compounds have potentially rapid, long-lasting anxiolytic, antidepressive and anti-inflammatory effects. We investigated whether the psychedelic compound (R)-2,5-dimethoxy-4-iodoamphetamine [(R)-DOI], a selective 5-HT2A receptor partial agonist, decreases stress-related behavior in male mice exposed to repeated social aggression. Additionally, we explored the likelihood that these behavioral changes are related to anti-inflammatory properties of [(R)-DOI]. Animals were subjected to the Stress Alternatives Model (SAM), an escapable social stress paradigm in which animals develop reactive coping strategies - remaining in the SAM arena (Stay) with a social aggressor, or dynamically initiated stress coping strategies that involve utilizing the escape holes (Escape) to avoid aggression. Mice expressing these behavioral phenotypes display behaviors like those in other social aggression models that separate animals into stress-vulnerable (as for Stay) or stress-resilient (as for Escape) groups, which have been shown to have distinct inflammatory responses to social stress. These results show that Stay animals have heightened cytokine gene expression, and both Stay and Escape mice exhibit plasma and neural concentrations of the inflammatory cytokine tumor necrosis factor-α (TNFα) compared to unstressed control mice. Additionally, these results suggest that a single administration of (R)-DOI to Stay animals in low doses, can increase stress coping strategies such as increasing attention to the escape route, promoting escape behavior, and reducing freezing during socially aggressive interaction in the SAM. Lower single doses of (R)-DOI, in addition to shifting behavior to suggest anxiolytic effects, also concomitantly reduce plasma and limbic brain levels of the inflammatory cytokine TNFα.


Asunto(s)
Adaptación Psicológica , Agresión , Anfetaminas , Alucinógenos , Estrés Psicológico , Animales , Masculino , Estrés Psicológico/tratamiento farmacológico , Estrés Psicológico/metabolismo , Alucinógenos/administración & dosificación , Alucinógenos/farmacología , Adaptación Psicológica/efectos de los fármacos , Adaptación Psicológica/fisiología , Ratones , Agresión/efectos de los fármacos , Agresión/fisiología , Anfetaminas/farmacología , Anfetaminas/administración & dosificación , Ratones Endogámicos C57BL , Factor de Necrosis Tumoral alfa/metabolismo , Agonistas del Receptor de Serotonina 5-HT2/farmacología , Agonistas del Receptor de Serotonina 5-HT2/administración & dosificación , Reacción de Fuga/efectos de los fármacos , Habilidades de Afrontamiento
12.
PLoS One ; 19(8): e0308263, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39167624

RESUMEN

Electrical transmission rights-of-way are ubiquitous and critical infrastructure across the landscape. Active vegetation management of these rights-of-way, a necessity to deliver electricity more safely, maintains these landscape features as stages of early successional habitat, a rarity in many regions, making these areas viable movement corridors for many taxa. The goals of this study were to (i) evaluate the effects of different electrical transmission landscape management practices on flowering plant and flower-visiting insect diversity parameters and (ii) generate conservation management inferences for these landscapes. In this study we tested the impact of three vegetation management levels across 18 electrical transmission sites. We evaluated the effects of treatment on bloom abundance and species richness as well as flower-visiting insect abundance and family richness. We identified 76541 flowers/inflorescences across 456 transects, including 188 species in 56 plant families. Additionally, we obtained data on 11361 flower-visitoring insects representing 33 families from 2376 pan trap sets. High vegetation management favored the reduction of coarse woody debris in the sites and harbored the highest level of abundance and richness of both floral resources and flower-visiting insects. We discuss that we can align social and ecological values of rights-of-way, ensuring their sustainability by applying regular and targeted integrated vegetation management. Thus, we can use rights-of-way landscapes not only as an effective management strategy for the delivery of essential human services, but also to provide conservation benefits for wild pollinators.


Asunto(s)
Biodiversidad , Conservación de los Recursos Naturales , Flores , Insectos , Animales , Insectos/fisiología , Conservación de los Recursos Naturales/métodos , Polinización , Ecosistema
13.
Artículo en Inglés | MEDLINE | ID: mdl-38444728

RESUMEN

The retina is comprised of diverse neural networks, signaling from photoreceptors to ganglion cells to encode images. The synaptic connections between these retinal neurons are crucial points for information transfer; however, the input-output relations of many synapses are understudied. Starburst amacrine cells in the retina are known to contribute to retinal motion detection circuits, providing a unique window for understanding neural computations. We examined the dual transmitter release of GABA and acetylcholine from starburst amacrine cells by optogenetic activation of these cells, and conducted patch clamp recordings from postsynaptic ganglion cells to record excitatory and inhibitory postsynaptic currents (EPSCs and IPSCs). As starburst amacrine cells exhibit distinct kinetics in response to objects moving in a preferred or null direction, we mimicked their depolarization kinetics using optogenetic stimuli by varying slopes of the rising phase. The amplitudes of EPSCs and IPSCs in postsynaptic ganglion cells were reduced as the stimulus rising speed was prolonged. However, the sensitivity of postsynaptic currents to the stimulus slope differed. EPSC amplitudes were consistently reduced as the steepness of the rising phase fell. By contrast, IPSCs were less sensitive to the slope of the stimulus rise phase and maintained their amplitudes until the slope became shallow. These results indicate that distinct synaptic release mechanisms contribute to acetylcholine and GABA release from starburst amacrine cells, which could contribute to the ganglion cells' direction selectivity.

14.
eNeuro ; 10(4)2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-37011954

RESUMEN

A rapidly approaching dark object evokes an evolutionarily conserved fear response in both vertebrates and invertebrates, young to old. A looming visual stimulus mimics an approaching object and triggers a similarly robust fear response in mice, resulting in freeze and flight. However, the retinal neural pathway responsible for this innate response has not been fully understood. We first explored a variety of visual stimuli that reliably induced these innate responses, and found that a looming stimulus with 2-d acclimation consistently evoked fear responses. Because the fear responses were triggered by the looming stimulus with moving edges, but not by a screen flipping from light to dark, we targeted the starburst amacrine cells (SACs), crucial neurons for retinal motion detection. We used intraocular injection of diphtheria toxin (DT) in mutant mice expressing diphtheria toxin receptors (DTR) in SACs. The looming-evoked fear responses disappeared in half of the DT-injected mice, and the other mice still exhibited the fear responses. The optomotor responses (OMRs) were reduced or eliminated, which occurred independent of the disappearance of the fear responses. A histologic examination revealed that ON SACs were reduced in both mouse groups preserved or absent fear responses. In contrast, the number of OFF SACs was different among two groups. The OFF SACs were relatively preserved in mice exhibiting continued fear responses, whereas they were ablated in mice lacking fear response to looming stimulation. These results indicate that OFF SACs and the direction-selective pathway in the retina play a role in looming-induced fear behaviors.


Asunto(s)
Células Amacrinas , Retina , Ratones , Animales , Células Amacrinas/metabolismo , Retina/metabolismo , Vías Nerviosas
15.
STAR Protoc ; 3(3): 101482, 2022 09 16.
Artículo en Inglés | MEDLINE | ID: mdl-35769922

RESUMEN

Bipolar cells are the second-order neurons in the retina that are less accessible for investigating their synaptic responses. Here, we present a protocol to conduct patch clamp recordings from bipolar cells in the wholemount retina from Ai32 mutant mice. We detail whole-cell patch-clamp recording from bipolar cells to examine their light-evoked responses to optogenetic stimulation, followed by imaging terminals of recorded cells to determine bipolar cell type. We describe light stimulus information to activate channelrhodopsin-2 (ChR2). For complete details on the use and execution of this protocol, please refer to Hellmer et al. (2021).


Asunto(s)
Neuronas , Retina , Animales , Ratones , Optogenética , Técnicas de Placa-Clamp , Retina/fisiología
16.
Med Sci Educ ; 32(1): 91-102, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-35154895

RESUMEN

PROBLEM: At present, formal training in adult learning principles, educational theories, and educational methods is not a core objective of most medical school curricula. As academic medical centers aim to develop the next generation of medical educators, students must be provided an opportunity to learn educational principles, engage in supervised teaching activities, and develop experiences in academic medicine to foster interest early in their development as educators. INTERVENTION: We developed a longitudinal medical education elective for fourth-year medical students, which was comprised of attending five seminars, leading 15 teaching sessions, formulating a medical education project, and writing a reflective essay. The seminars covered the history of medical education in the USA, adult learning theory and teaching principles, use of various teaching strategies and formats, construction and organization of curricula, effective models of evaluation and feedback provision, and principles of educational research. CONTEXT: This exploratory quasi-experiment incorporated a concurrent mixed methods data collection approach via pre- and post-seminar surveys and narrative reflection essay document analyses. IMPACT: Learners revealed favorable changes in their self-efficacy and self-perceived knowledge and attitudes towards medical education. A qualitative analysis of the reflective essays revealed five thematic categories (learning impacts, medical educator growth, leadership growth, medical school reflections, and future professional plans) and thirteen sub-categories. Students found many opportunities to implement high-quality educational projects, expressed commitment to pursuing teaching careers, and felt better equipped to assume a leadership role as change agents in academic medicine. LESSONS LEARNED: Findings are likely relevant to critical stakeholders who advocate for the inclusion of formal educational skills training into medical education curricula.

18.
Mol Syst Des Eng ; 6(12): 1003-1015, 2021 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-35096418

RESUMEN

Inspired by Nature's tunability driven by the modulation of structural organization, we utilize peptide motifs as an approach to tailor not only hierarchical structure, but also thermo-responsive shape memory properties of conventional polymeric materials. Specifically, poly(ß-benzyl-L-aspartate)-b-poly(dimethylsiloxane)-b-poly(ß-benzyl-L-aspartate) was incorporated as the soft segment in peptide-polyurea hybrids to manipulate hierarchical ordering through peptide secondary structure and a balance of inter- and intra-molecular hydrogen bonding. Employing these bioinspired peptidic polyureas, we investigated the influence of secondary structure on microphase-separated morphology, and shape fixity and recovery via attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), small-angle X-ray scattering (SAXS) and dynamic mechanical analysis (DMA). The ß-sheet motifs promoted phase mixing through extensive inter-molecular hydrogen bonding between the hard block and peptide segments and provided an increased chain elasticity, resulting in decreased shape fixity compared to a non-peptidic control. In contrast, intra-molecular hydrogen bonding driven by the α-helical arrangements yielded a microphase-separated and hierarchically ordered morphology, leading to an increase in the shape fixing ratio. These results indicate that peptide secondary structure provides a convenient handle for tuning shape memory properties by regulating hydrogen bonding with the surrounding polyurea hard segment, wherein extent of hydrogen bonding and phase mixing between the peptidic block and hard segment dictate the resulting shape memory behaviour. Furthermore, the ability to shift secondary structure as a function of temperature was also demonstrated as a pathway to influence shape memory response. This research highlights that peptide secondary conformation influences the hierarchical ordering and modulates the shape memory response of peptide-polymer hybrids. We anticipate that these findings will enable the design of smart bio-inspired materials with responsive and tailored function via a balance of hydrogen bonding character, structural organization, and mechanics.

19.
Cell Rep ; 37(11): 110106, 2021 12 14.
Artículo en Inglés | MEDLINE | ID: mdl-34910920

RESUMEN

Retinal bipolar cells are second-order neurons that transmit basic features of the visual scene to postsynaptic partners. However, their contribution to motion detection has not been fully appreciated. Here, we demonstrate that cholinergic feedback from starburst amacrine cells (SACs) to certain presynaptic bipolar cells via alpha-7 nicotinic acetylcholine receptors (α7-nAChRs) promotes direction-selective signaling. Patch clamp recordings reveal that distinct bipolar cell types making synapses at proximal SAC dendrites also express α7-nAChRs, producing directionally skewed excitatory inputs. Asymmetric SAC excitation contributes to motion detection in On-Off direction-selective ganglion cells (On-Off DSGCs), predicted by computational modeling of SAC dendrites and supported by patch clamp recordings from On-Off DSGCs when bipolar cell α7-nAChRs is eliminated pharmacologically or by conditional knockout. Altogether, these results show that cholinergic feedback to bipolar cells enhances direction-selective signaling in postsynaptic SACs and DSGCs, illustrating how bipolar cells provide a scaffold for postsynaptic microcircuits to cooperatively enhance retinal motion detection.


Asunto(s)
Potenciales de Acción , Movimiento Celular , Colinérgicos/metabolismo , Células Bipolares de la Retina/fisiología , Sinapsis/fisiología , Transmisión Sináptica , Receptor Nicotínico de Acetilcolina alfa 7/fisiología , Animales , Femenino , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Células Ganglionares de la Retina/fisiología , Vías Visuales
20.
Orthop Traumatol Surg Res ; 106(1): 61-66, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-31883868

RESUMEN

INTRODUCTION: Sleep dysfunction in patients with rotator cuff tears has been previously evaluated only using subjective measures. Objective parameters of sleep quality amongst rotator cuff tear patients are scarce in the literature. The aim of this study is to compare objective sleep data to historical controls and to subjective patient-reported sleep quality in patients with rotator cuff tears. HYPOTHESIS: We hypothesized that patients with rotator cuff tears would demonstrate objectively poor sleep quality based on actigraphy when compared to a historical control group. Secondarily, we hypothesize that objective sleep quality measures will correlate poorly with traditionally used questionnaires and other subjective assessments. MATERIALS AND METHODS: Twenty patients with full-thickness rotator cuff tears wore a highly validated activity monitor for 2 consecutive weeks for objective assessment and completed a sleep diary during the same period. Patients completed multiple questionnaires pertaining to their shoulder function and subjective assessment of sleep quality. Objective sleep assessments were compared to patients' sleep diary data and to subjective sleep data from a historical cohort of 969 healthy adults aged 57-97 years. RESULTS: Mean total sleep time, sleep onset latency, wake after sleep onset (WASO), and sleep efficiency were all significantly worse in the study cohort compared to the historical cohort (p=0.0338, p=0.0040, p<0.0001, and p=0.0474, respectively). Pittsburgh Sleep Quality Index (PSQI) scores did not correlate with sleep efficiency (r=0.3143, p=0.2040) or WASO (r=-0.3068, p=0.2153). Visual analog scale scores correlated with PSQI scores (r=0.5260, p=0.0249) and Epworth Sleepiness Scale scores (r=0.4863, p=0.0407). Patients tended to overreport their time spent asleep via a sleep diary compared to objective time asleep (p=0.0050). DISCUSSION: This study of objective sleep measures demonstrated poor sleep quality in patients with rotator cuff tears with shorter sleep duration, frequent awakenings, and decreased efficiency. Subjective assessments of sleep did not correlate with objective findings. LEVEL OF EVIDENCE: Level II, prospective cohort study.


Asunto(s)
Lesiones del Manguito de los Rotadores , Sueño , Anciano , Anciano de 80 o más Años , Estudios de Casos y Controles , Humanos , Persona de Mediana Edad , Dimensión del Dolor , Estudios Prospectivos , Manguito de los Rotadores , Lesiones del Manguito de los Rotadores/complicaciones , Resultado del Tratamiento
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