Nurses in a variety of settings frequently use behavior modification strategies to promote health behavior change. Shaming is one such behavior modification tool, but its use in nursing is poorly ...understood. A concept analysis using Walker and Avant's method was performed. After an extensive literature review, a conceptual definition of shaming is proposed and defining attributes, antecedents, and consequences are presented. Shaming is also differentiated from related concepts often used synonymously such as stigmatization and incivility. Shaming as a behavior modification strategy is incongruous with nursing values and its utilization in nursing warrants further investigation.
Nurses in a variety of settings frequently use behavior modification strategies to promote health behavior change. Shaming is one such behavior modification tool, but its use in nursing is poorly ...understood. A concept analysis using Walker and Avant's method was performed. After an extensive literature review, a conceptual definition of shaming is proposed and defining attributes, antecedents, and consequences are presented. Shaming is also differentiated from related concepts often used synonymously such as stigmatization and incivility. Shaming as a behavior modification strategy is incongruous with nursing values and its utilization in nursing warrants further investigation.
Twitching motility-mediated biofilm expansion is a complex, multicellular behavior that enables the active colonization of surfaces by many species of bacteria. In this study we have explored the ...emergence of intricate network patterns of interconnected trails that form in actively expanding biofilms of Pseudomonas aeruginosa . We have used high-resolution, phase-contrast time-lapse microscopy and developed sophisticated computer vision algorithms to track and analyze individual cell movements during expansion of P. aeruginosa biofilms. We have also used atomic force microscopy to examine the topography of the substrate underneath the expanding biofilm. Our analyses reveal that at the leading edge of the biofilm, highly coherent groups of bacteria migrate across the surface of the semisolid media and in doing so create furrows along which following cells preferentially migrate. This leads to the emergence of a network of trails that guide mass transit toward the leading edges of the biofilm. We have also determined that extracellular DNA (eDNA) facilitates efficient traffic flow throughout the furrow network by maintaining coherent cell alignments, thereby avoiding traffic jams and ensuring an efficient supply of cells to the migrating front. Our analyses reveal that eDNA also coordinates the movements of cells in the leading edge vanguard rafts and is required for the assembly of cells into the “bulldozer” aggregates that forge the interconnecting furrows. Our observations have revealed that large-scale self-organization of cells in actively expanding biofilms of P. aeruginosa occurs through construction of an intricate network of furrows that is facilitated by eDNA.
Cell-cell communication is an important mechanism for information exchange promoting cell survival for the control of features such as population density and differentiation. We determined that ...Plasmodium falciparum-infected red blood cells directly communicate between parasites within a population using exosome-like vesicles that are capable of delivering genes. Importantly, communication via exosome-like vesicles promotes differentiation to sexual forms at a rate that suggests that signaling is involved. Furthermore, we have identified a P. falciparum protein, PfPTP2, that plays a key role in efficient communication. This study reveals a previously unidentified pathway of P. falciparum biology critical for survival in the host and transmission to mosquitoes. This identifies a pathway for the development of agents to block parasite transmission from the human host to the mosquito.
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•Malaria-infected red blood cells communicate using exosome-like vesicles•Communication via exosome-like vesicles promotes differentiation to sexual forms•Pathway of P. falciparum biology for survival in host and mosquito transmission•Identification of a pathway for development of agents to block parasite transmission
The malaria-causing pathogen Plasmodium falciparum infects red blood cells and uses exosome-like vesicles to directly communicate within a population. These vesicles transmit information required for parasite survival, population density, and sexual differentiation within the host.
The baroreflex is a multi‐input, multi‐output physiological control system that regulates blood pressure by modulating nerve activity between the brainstem and the heart. Existing computational ...models of the baroreflex do not explicitly incorporate the intrinsic cardiac nervous system (ICN), which mediates central control of heart function. We developed a computational model of closed‐loop cardiovascular control by integrating a network representation of the ICN within central control reflex circuits. We examined central and local contributions to the control of heart rate, ventricular functions, and respiratory sinus arrhythmia (RSA). Our simulations match the experimentally observed relationship between RSA and lung tidal volume. Our simulations predicted the relative contributions of the sensory and the motor neuron pathways to the experimentally observed changes in the heart rate. Our closed‐loop cardiovascular control model is primed for evaluating bioelectronic interventions to treat heart failure and renormalize cardiovascular physiology.
Bacteria form biofilms to facilitate colonization of biotic and abiotic surfaces, and biofilm formation on indwelling medical devices is a common cause of hospital-acquired infection. Although it is ...well-recognized that the exopolysaccharide capsule is one of the key bacterial components for biofilm formation, the underlying biophysical mechanism is poorly understood. In the present study, nanomechanical measurements of wild type and specific mutants of the pathogen, Klebsiella pneumoniae, were performed in situ using atomic force microscopy (AFM). Theoretical modeling of the mechanical data and static microtiter plate biofilm assays show that the organization of the capsule can influence bacterial adhesion, and thereby biofilm formation. The capsular organization is affected by the presence of type 3 fimbriae. Understanding the biophysical mechanisms for the impact of the structural organization of the bacterial polysaccharide capsule on biofilm formation will aid the development of strategies to prevent biofilm formation.
Atomic force microscopy (AFM) friction measurements on hard and soft materials remain a challenge due to the difficulties associated with accurately calibrating the cantilever for lateral force ...measurement. One of the most widely accepted lateral force calibration methods is the wedge method. This method is often used in a simplified format but in so doing sacrifices accuracy. In the present work, we have further developed the wedge method to provide a lateral force calibration method for integrated AFM probes that is easy to use without compromising accuracy and reliability. Raw friction calibration data are collected from a single scan image by continuous ramping of the set point as the facets of a standard grating are scanned. These data are analysed to yield an accurate lateral force conversion/calibration factor that is not influenced by adhesion forces or load deviation. By demonstrating this new calibration method, we illustrate its reliability, speed and ease of execution. This method makes accessible reliable boundary lubrication studies on adhesive and heterogeneous surfaces that require spatial resolution of frictional forces.
•We develop a simple and accurate method for lateral force calibration in AFM friction measurements.•We detail the basis of the method and illustrate how to use it and its reliability with example data.•Our method is easy, accurate and accounts for the affects of adhesion on friction measurements.•The method is applicable to integrated probes, as opposed to colloidal probes.•This allows accurate AFM friction measurements on spatially heterogeneous and adhesive surfaces.
Increasing rates of antimicrobial-resistant medically important bacteria require the development of new, effective therapeutics, of which antimicrobial peptides (AMPs) are among the promising ...candidates. Many AMPs are membrane-active, but their mode of action in killing bacteria or in inhibiting their growth remains elusive. This study used atomic force microscopy (AFM) to probe the mechanobiology of a model AMP (a derivative of melittin) on living Klebsiella pneumoniae bacterial cells. We performed in situ biophysical measurements to understand how the melittin peptide modulates various biophysical behaviors of individual bacteria, including the turgor pressure, cell wall elasticity, and bacterial capsule thickness and organization. Exposure of K. pneumoniae to the peptide had a significant effect on the turgor pressure and Young’s modulus of the cell wall. The turgor pressure increased upon peptide addition followed by a later decrease, suggesting that cell lysis occurred and pressure was lost through destruction of the cell envelope. The Young’s modulus also increased, indicating that interaction with the peptide increased the rigidity of the cell wall. The bacterial capsule did not prevent cell lysis by the peptide, and surprisingly, the capsule appeared unaffected by exposure to the peptide, as capsule thickness and inferred organization were within the control limits, determined by mechanical measurements. These data show that AFM measurements may provide valuable insights into the physical events that precede bacterial lysis by AMPs.
Summary
Objective
To evaluate safety, tolerability, seizure frequency, and regional variations in treatment responses with the AMPA antagonist, perampanel, in a large extension study during up to ...3 years of treatment.
Methods
Patients ≥12 years old with partial‐onset seizures despite treatment with 1–3 antiepileptic drugs at baseline completed a perampanel phase III trial and entered extension study 307 (NCT00735397). Patients were titrated to 12 mg/day (or their individual maximum tolerated dose) during the blinded conversion period, followed by open‐label maintenance. Exposure, safety (adverse events AEs, vital signs, weight, electrocardiography ECG, laboratory values) and seizure outcomes were analyzed; key measures were assessed by geographic regions.
Results
Among 1,216 patients, median exposure was 1.5 years (range 1 week to 3.3 years), with >300 patients treated for >2 years. Treatment retention was 58.5% at cutoff. AEs reported in ≥10% of patients were dizziness, somnolence, headache, fatigue, irritability, and weight increase. Only dizziness and irritability caused discontinuation in >1% of patients (3.9% and 1.3%, respectively). The only serious AEs reported in >1% of patients were epilepsy‐related (convulsion, 3.0%; status epilepticus, 1.1%). No clinically relevant changes in vital signs, ECG or laboratory parameters were seen. After titration/conversion, responder rate and median percentage change from baseline in seizure frequency were stable: 46% for both measures at 9 months (in 980 patients with ≥9 months' exposure) and 58% and 60%, respectively, at 2 years (in the 337 patients with 2 years' exposure). Median percentage reduction in frequency of secondarily generalized (SG) seizures ranged from 77% at 9 months (N = 422) to 90% at 2 years (N = 141). Among the 694 patients with maintenance data ≥1 year, 5.3% were seizure‐free for the entire year.
Significance
No new safety signals emerged during up to 3 years of perampanel exposure in 39 countries. Seizure responses remained stable, with marked reductions, particularly in SG seizures.
A PowerPoint slide summarizing this article is available for download in the Supporting Information section here.
The surface polymers of bacteria determine the ability of bacteria to adhere to a substrate for colonization, which is an essential step for a variety of microbial processes, such as biofilm ...formation and biofouling. Capsular polysaccharides and fimbriae are two major components on a bacterial surface, which are critical for mediating cell–surface interactions. Adhesion and viscoelasticity of bacteria are two major physical properties related to bacteria–surface interactions. In this study, we employed atomic force microscopy (AFM) to interrogate how the adhesion work and the viscoelasticity of a bacterial pathogen, Klebsiella pneumoniae, influence biofilm formation. To do this, the wild-type, type 3 fimbriae-deficient, and type 3 fimbriae-overexpressed K. pneumoniae strains have been investigated in an aqueous environment. The results show that the measured adhesion work is positively correlated to biofilm formation; however, the viscoelasticity is not correlated to biofilm formation. This study indicates that AFM-based adhesion measurements of bacteria can be used to evaluate the function of bacterial surface polymers in biofilm formation and to predict the ability of bacterial biofilm formation.
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