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BACKGROUND: The methodological quality of open access studies has long been questioned due to increasing popularity and accessibility. The objective of this study is to compare the methodological quality of open access versus traditional journal publications in the plastic surgery literature. METHODS: Four traditional plastic surgery journals with their sister open access journals were chosen. For each of the eight journals, 10 articles were randomly selected for inclusion. Methodological quality was examined using validated instruments. Publication descriptors were compared to methodological quality values using ANOVA. Logistic regression was used to compare quality scores between open access and traditional journals. RESULTS: There was a wide distribution of levels of evidence, with a quarter being level one. Regression of non-randomized studies indicated a significantly higher proportion of traditional journal articles were of high methodological quality (89.6%) when compared to open access journals (55.6%; p < 0.05). This difference persisted in three quarter of the sister journal groups. No publication descriptions were associated with methodological quality. CONCLUSIONS: Methodological quality scores were higher among traditional access journals. Higher degrees of peer review may be necessary to ensure appropriate methodological quality in open access plastic surgery publications. LEVEL OF EVIDENCE V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .
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Procedimientos de Cirugía Plástica , Cirugía Plástica , Humanos , Acceso a la InformaciónRESUMEN
Field sterility for K-wire insertion outside the main operating room is much cheaper and greener (ie, there is less waste). It permits increased access to more affordable surgery because unnecessary sedation and full sterility are eliminated. Early pain-guided protected movement of K-wired finger fractures at 3 to 5 days leads to less stiffness. It will not result in loss of reduction or infection around K-wires if patients avoid "pain" (ie, do not perform movements that hurt). Early protected movement and early removal of K-wires at 2 to 4 weeks contribute to less stiffness after operative hand/finger fracture reduction and stabilization.
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Traumatismos de los Dedos , Fracturas Óseas , Infertilidad , Hilos Ortopédicos , Traumatismos de los Dedos/cirugía , Fijación Interna de Fracturas , Fracturas Óseas/cirugía , Humanos , Resultado del TratamientoRESUMEN
Primary esophageal melanoma remains a rare entity with less than 350 case reports noted in the current literature. This diagnosis is associated with a poor prognosis and early detection and management remains fundamental. In this report, we examine the case of an 80-year-old female who presented with a 1-year course of progressive dysphagia and weight loss. Investigations revealed a primary esophageal melanoma with no evidence of metastases. Pathology did not identify any targetable markers for systematic therapy and thus the patient successfully underwent a minimally invasive esophagectomy. Her postoperative course involved endoscopic esophageal dilatations due to an anastomotic stricture, as well as primary lung adenocarcinoma treated with radiotherapy but has otherwise remained without evidence of melanoma recurrence after 25 months from her surgery.
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BACKGROUND: Despite its increasing use in craniofacial surgery, the evidence for piezosurgery over conventional bone-cutting techniques has not been critically appraised. The purpose of this systematic review and meta-analysis was to identify and assess the evidence that exists for the use of piezosurgery in craniofacial surgery. METHODS: A systematic review was undertaken using a computerized search. Publication descriptors, methodologic details, and outcomes were extracted. Articles were assessed using the methodologic index for nonrandomized studies and Cochrane instruments. Random effects meta-analysis was completed. RESULTS: Thirty-nine studies were included. Most studies were published within the past 5 years (51.3 percent) and were randomized controlled trials (56.4 percent). The mean age of patients was 27 years (range, 0.2 to 57 years), and the mean sample size was 44 (range, 12 to 180). Meta-analysis revealed that compared to conventional instruments, piezosurgery had a lower postoperative incidence of sensory disturbance, principally in mandibular procedures (OR, 0.29; 95 percent CI, 0.11 to 0.77; p = 0.01) and pain at postoperative day 3 (mean difference, -0.86; 95 percent CI, -1.20 to -0.53; p < 0.01). There was no statistically significant difference in operating room time (mean difference, 8.60; 95 percent CI, -1.27 to 18.47; p = 0.80) or osteotomy time (mean difference, 0.35; 95 percent CI, -2.99 to 3.68; p = 0.84). Most studies were clinically homogenous (92 percent) and of high quality based on the methodologic index for nonrandomized studies instrument (84 percent). Few studies had domains at high risk of bias based on the Cochrane instrument (28.6 percent). CONCLUSIONS: Piezosurgery has considerable benefits when compared to conventional instruments. Future studies should investigate its cost-effectiveness and benefits in terms of blood loss, edema/ecchymosis, and patient satisfaction.
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Mandíbula/cirugía , Osteotomía/métodos , Satisfacción del Paciente , Piezocirugía/métodos , Rinoplastia/métodos , HumanosRESUMEN
BACKGROUND: Hand rejuvenation is an increasingly popular cosmetic procedure for hand atrophy and aging. The objective of this study is to systematically evaluate the techniques, outcomes, and complications of surgical hand rejuvenation. METHODS: A systematic review was undertaken using a computerized search. Publication descriptors, methodological details, techniques, outcomes, and complications were extracted. Articles were assessed using the MINORS and Cochrane instruments. RESULTS: Thirty-one studies were included. Most studies were published in the last five years (51.6 percent) and were prospective case series (35.5 percent). The mean age of patients was 56 (range 21-82), while the mean sample size was 47 (range 10-220). The most commonly examined interventions were Radiesse (32.2 percent) and fat grafting (32.2 percent). Major complications were not observed in any study, while minor complications such as edema and pain were temporary. Injection techniques varied, however, the proximal to distal fanning technique and using a cannula was associated with a lower risk of complications. Both Radiesse and fat grafting had robust long-term esthetic outcomes. CONCLUSIONS: Hand rejuvenation is a safe and efficacious surgical intervention to reduce dorsal hand atrophy. Further studies are needed to compare the long-term outcomes of common interventions. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .
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Rejuvenecimiento , Envejecimiento de la Piel , Edema , Estética , Humanos , Satisfacción del PacienteRESUMEN
Ulnar nerve (UN) entrapment is a common peripheral neuropathy and can lead to dysfunction of both sensory and motor function of the hand. Surgical release is the mainstay of treatment, but post-operative rehabilitation of UN innervated intrinsic muscles is lacking evidence. This cohort study utilized surface electromyography (EMG) and assessed the activation of UN innervated intrinsic and extrinsic hand muscles during four exercises in healthy participants. Exercises included rotating baoding balls, squeezing a stress ball or grip device every second, and repetitive finger abduction against a rubber band. Normalized percent activation of each muscle was calculated for each exercise. It was demonstrated that rubber band resistance (RBR) finger abduction showed significantly increased activation in both intrinsic muscles tested, while minimizing activation of the one tested UN innervated extrinsic muscle. Thus, to best target the intrinsic hand muscles without fatiguing extrinsic muscles, the inexpensive and practical RBR exercise is beneficial in post-UN release rehabilitation.
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Síndromes de Compresión del Nervio Cubital , Nervio Cubital , Estudios de Cohortes , Descompresión , Electromiografía , Mano , Humanos , Músculo Esquelético/inervaciónRESUMEN
BACKGROUND: Latissimus dorsi (LD) flap is a workhorse flap in breast reconstruction. Despite many advantages, the primary criticism of this flap is the requirement of a second surgery to exchange expansion devices for permanent implants. This study reports a single-stage reconstruction and outcomes wherein Spectrum devices (Mentor, Irving, TX), which serve as expanders and permanent implants, are used, and expansion ports are removed under local anesthetic. METHODS: A retrospective chart review of all patients undergoing LD flap reconstruction with Spectrum device by a single surgeon at a single center during a 10-year period was performed. All patients, unilateral/bilateral, immediate/delayed were included. Details of implants, surgical procedure(s), and follow-up visits were assessed for patient outcomes. RESULTS: In total, 41 patients and 56 breasts were included. Of the total patients, 58.5% retained the Spectrum device and had the expansion port removed under local anesthetic. An estimated 6 major complications occurred (14.6%), requiring return to the operating room: 3 patients required a capsulectomy, 1 a capsulotomy/implant repositioning, one had loss of implant (infection), and 1 had venous congestion of the flap. Eleven minor complications occurred (26.8%): 5 seromas (3 at the breast site, 2 at the donor site), 3 delayed wound healings (2 at donor site, 1 at breast site), 1 mastectomy flap necrosis, 2 infections (1 at each breast site, 1 at donor site). CONCLUSIONS: This study provides details of a single-stage LD flap with Spectrum device breast reconstruction that can be considered when performing an LD reconstruction. This technique is efficient and safe with comparable complication profile.
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BACKGROUND: Our objective is to evaluate the evidence on the aesthetic effect and complications of skin-OOM strip resection compared to skin only upper blepharoplasty. METHODS: A systematic search of EMBASE, PubMed, Cochrane and Google Scholar databases was performed using our search strategy through to 31 December 2019. Only comparative studies of the two upper blepharoplasty techniques were included. Three reviewers performed study selection process, data extraction, and quality assessment. RESULTS: A total of six articles were eligible for final inclusion. The included studies consist of two controlled retrospective cohorts and four small randomized controlled studies (RCT). Three of which, were double blinded. Those RCTs were assigned level 2 evidence due to small size and methodological limitations. The sample size of included was studies 407 in the two retrospective studies and 57 in the four RCTs. The outcomes showed that resection of OOM along with skin in upper blepharoplasty showed no difference in long-term aesthetic outcome when skin only procedure is performed. Muscle strip resection was associated with initially higher ophthalmological morbidity (edema, bruising, pain, dry eye, sluggish eye closure and lagopthalmos). Those resolved a few weeks later with conservative treatment. CONCLUSION: The resection of OOM along with skin in upper blepharoplasty showed no difference in long-term aesthetic outcome and was associated with initially higher ophthalmological morbidity compared to skin only procedure. While we are not suggesting that OOM resection is never required, the evidence strongly support its preservation during standard upper blepharoplasty. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to Table of Contents or the online Instructions to Authors www.springer.com/00266 .
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Blefaroplastia , Enfermedades de los Párpados , Estética , Párpados/cirugía , Músculos Faciales/cirugía , Humanos , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
BACKGROUND: Abdominal adhesions (AAs) are post-traumatic fibrous bands that connect visceral and/or peritoneal surfaces, leading to possible long-term complications. The effect of a novel antifibrotic selective angiotensin II type 2 receptor agonist, compound 21 (C21) on AA formation was assessed in a murine model. METHODS: Female BALB/c mice were laparotomized and the cecum and overlying parietal peritoneum abraded. C21 (10 µg/kg) or saline (vehicle) were administered orally or intraperitoneally daily. Mice were sacrificed 8 days after surgery, adhesions graded, and peritoneal fluid collected for transforming growth factor (TGF)-ß levels. Laparotomy incisions were excised for immunohistochemistry. In vitro, scratch assays were performed using primary parietal peritoneal fibroblasts and visceral mesothelial cells treated with C21 (10 µM), angiotensin II (1 µM), or both. Western blot analysis of primary cell lysates was performed for total and phosphorylated SMAD 2/3. RESULTS: Oral and intraperitoneal C21 reduced AA formation and TGF-ß levels in peritoneal fluid. Surgical incisions demonstrated decreased α-smooth muscle actin expression in C21-treated animals, but no difference in vascularity, macrophage infiltration, collagen I/III distribution and density, and dermal thickness. Migration and expression of phosphorylated SMAD 2/3 was reduced in parietal peritoneal fibroblasts and visceral mesothelial cells treated with C21. CONCLUSIONS: Local and systemic C21 administration reduced or completely prevented AA formation. These findings may be attributed to decreased intraperitoneal TGF-ß in vivo and decreased migration of peritoneal fibroblasts and visceral mesothelial cells. Importantly, C21 did not have histologically quantifiable effects on laparotomy wounds, suggesting C21 could reduce AA formation without compromising laparotomy healing.
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Imidazoles/farmacología , Peritoneo/patología , Complicaciones Posoperatorias/prevención & control , Receptor de Angiotensina Tipo 2/agonistas , Sulfonamidas/farmacología , Tiofenos/farmacología , Adherencias Tisulares/prevención & control , Administración Oral , Animales , Movimiento Celular/efectos de los fármacos , Células Cultivadas , Modelos Animales de Enfermedad , Femenino , Fibroblastos/efectos de los fármacos , Fibroblastos/patología , Fibrosis , Humanos , Imidazoles/uso terapéutico , Inyecciones Intraperitoneales , Ratones , Peritoneo/efectos de los fármacos , Peritoneo/cirugía , Cuidados Posoperatorios/métodos , Complicaciones Posoperatorias/patología , Cultivo Primario de Células , Sulfonamidas/uso terapéutico , Tiofenos/uso terapéutico , Adherencias Tisulares/etiología , Adherencias Tisulares/patología , Factor de Crecimiento Transformador beta/metabolismo , Cicatrización de Heridas/efectos de los fármacosRESUMEN
BACKGROUND: Autogenous costal cartilage grafts (ACCG) are frequently used in secondary rhinoplasty; however, these grafts tend to warp. The objective of this study is to systematically evaluate current interventions to prevent warping of ACCGs and to assess long-term outcomes with their use. METHODS: A systematic review was undertaken using a computerized search. Eligible articles assessed adult patients undergoing secondary rhinoplasty with ACCGs. Interventions to reduce warping were examined. Publication descriptors were extracted, heterogeneity was examined, and methodological quality of articles was assessed. RESULTS: Eighteen studies were included. Most studies were published after 2010 (83.3%), assessed a single intervention (83.3%), and were of levels of evidence III and IV. Mean patient age was 30 (range 5-95 years) and studies included a mean of 64 cases (range 9-357). Nine of the 15 non-comparative studies were considered of high methodological quality, while all 3 comparative studies were considered high quality. Secondary rhinoplasties which did not describe a method to address warping showed increased rates of warping compared to counter balancing techniques, chimeric grafts, titanium microplating, Kirschner wire and suture usage, irradiation, and various carving techniques. Rates of warping remained low with no major complications with the use of a variety of approaches. CONCLUSIONS: ACCG warping during secondary rhinoplasty can be alleviated with a variety of techniques with no clear difference in outcomes between approaches. Plastic surgeons may consider adopting one of the various techniques described in order to reduce warping, maximize aesthetic outcomes and patient satisfaction.
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Cartílago Costal/cirugía , Rinoplastia , Animales , Recolección de Datos , Humanos , Rinoplastia/métodos , Suturas , Trasplante AutólogoRESUMEN
Cell migration is an important biological phenomenon involved in many homeostatic and aberrant physiological processes. Phosphorylation of the focal adhesion adaptor protein, paxillin, on serine 273 (S273) has been implicated as a key regulator of cell migration. Here, it is shown that phosphorylation on paxillin S273 leads to highly migratory cells with small dynamic adhesions. Adhesions at protrusive edges of the cell were more dynamic than adhesions at retracting edges. Temporal image correlation microscopy revealed that these dynamic adhesions undergo rapid binding of paxillin, PAK1 and ßPIX. We identified membrane proximal adhesion subdomains in protrusive regions of the cell that show rapid protein binding that is dependent on paxillin S273 phosphorylation, PAK1 kinase activity and phosphatases. These dynamic adhesion subdomains corresponded to regions of the adhesion that also show co-binding of paxillin/PAK1 and paxillin/ßPIX complexes. It is likely that parts of individual adhesions are more dynamic while others are less dynamic due to their association with the actin cytoskeleton. Variable adhesion and binding dynamics are regulated via differential paxillin S273 phosphorylation across the cell and within adhesions and are required for regulated cell migration. Dysregulation through phosphomutants, PAK1-KD or ßPIX mutants resulted in large stable adhesions, long protein binding times and slow cell migration. Dysregulation through phosphomimics or PAK1-CA led to small dynamic adhesions and rapid cell migration reminiscent of highly migratory cancer cells. Thus, phosphorylation of paxillin S273 is a key regulator of cell migration through recruitment of ßPIX and PAK1 to sites of adhesion.
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Adhesión Celular , Movimiento Celular , Paxillin/metabolismo , Factores de Intercambio de Guanina Nucleótido Rho/metabolismo , Quinasas p21 Activadas/metabolismo , Animales , Células CHO , Cricetulus , Microscopía Intravital , Microscopía Fluorescente , Mutación , Paxillin/genética , Fosforilación/genética , Unión Proteica/genética , Dominios Proteicos/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Factores de Intercambio de Guanina Nucleótido Rho/genética , Serina/genética , Serina/metabolismo , Quinasas p21 Activadas/genéticaRESUMEN
BACKGROUND: Angiotensin II engagement of angiotensin II type 1 receptor (AT1R) is implicated in fibrogenesis, with AT1R blockers used clinically to attenuate cardiac and renal fibrosis. The authors tested the hypothesis that the AT1R blocker losartan could reduce postsurgical cutaneous scarring in rats. METHODS: Human dermal fibroblasts were treated with losartan and assessed for viability, contractile activity, migration, and profibrotic gene transcription by means of calcein, collagen gel, scratch, and quantitative reverse transcriptase polymerase chain reaction assays, respectively. Monocyte migration and adhesion to losartan-treated and control fibroblasts were examined. Losartan effects in vivo were assessed using a mechanical distraction hypertrophic scar model. Three days after incisions were made and closed on their backs, rats were assigned randomly to receive drinking water with or without losartan (1 mg/kg per day; n = 6 per group). Distraction devices were applied and activated up to day 14. On day 28, scars underwent cross-sectional area and elevation index analyses, and α-SMA (alpha-smooth muscle actin) and CD68 (monocyte/macrophage marker) immunostaining. RESULTS: Losartan-treated human dermal fibroblasts displayed decreased contractile activity, migration, and gene expression of transforming growth factor-ß1, collagen I, and monocyte chemoattractant protein-1 relative to controls (p < 0.05). Monocyte migration and adhesion to losartan-treated fibroblasts were reduced (p < 0.01). Compared to controls, scars from losartan-treated rats demonstrated decreased cross-sectional area (19.4 ± 3.1 mm versus 45.0 ± 5.2 mm; p = 0.002), elevation index (1.5 ± 0.1 versus 2.6 ± 0.3; p = 0.003), and α-SMA and CD68 immunostaining (p < 0.001). CONCLUSIONS: Losartan decreases myofibroblast activity and reduces monocyte trafficking to cutaneous scar. These findings support losartan as a potential novel therapy for the prevention of hypertrophic scars.
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Bloqueadores del Receptor Tipo 1 de Angiotensina II/farmacología , Cicatriz Hipertrófica/prevención & control , Fibroblastos/efectos de los fármacos , Losartán/farmacología , Miofibroblastos/efectos de los fármacos , Receptor de Angiotensina Tipo 1/efectos de los fármacos , Animales , Movimiento Celular/efectos de los fármacos , Células Cultivadas , Modelos Animales de Enfermedad , Fibroblastos/fisiología , Humanos , Miofibroblastos/citología , Distribución Aleatoria , Ratas , Receptor de Angiotensina Tipo 1/metabolismo , Valores de Referencia , Sensibilidad y EspecificidadRESUMEN
BACKGROUND: As understanding of poor physician mental health and burnout strengthens, it is becoming important to identify factors that detract from wellbeing. Shame-based learning (SBL) is detrimental to psychological health and can contribute to burnout, substance abuse and suicide. This study endeavoured to quantify the unknown prevalence and effects of SBL in Canadian plastic surgery programs. METHODS: An electronic survey was sent to all attending surgeons and trainee (residents and fellows) members of the Canadian Society of Plastic Surgeons. SBL was assessed using a validated questionnaire. Data was analyzed using descriptive statistics and thematic analysis. RESULTS: 98 responses (14.7%) comprising of 63 attending surgeons and 36 trainees were received. The majority of attending surgeons (78 percent) and trainees (67%) have been shamed. Fourteen percent of trainees and 9% of attending surgeons felt that SBL is necessary. The most common event provoking shaming for trainees was wrong answers (56%) and for attending surgeons was disagreement in clinical care (21%). For both groups, shamers were in positions of authority. The most common effect of SBL in trainees was a loss of self-confidence (53%), compared to no negative effect in attending surgeons (49 percent). Thirty-nine percent of trainees dealt with shaming events with support from fellow trainees (39 percent), while attending surgeons kept it to themselves (40 percent). CONCLUSION: SBL is present in Canadian plastic surgery residency programs and has numerous detrimental effects. To foster better mental health, residency programs should identify ongoing SBL and make efforts to transition to healthier feedback strategies.
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Focal adhesions are protein complexes that anchor cells to the extracellular matrix. During migration, the growth and disassembly of these structures are spatiotemporally regulated, with new adhesions forming at the leading edge of the cell and mature adhesions disassembling at the rear. Signalling proteins and structural cytoskeletal components tightly regulate adhesion dynamics. Paxillin, an adaptor protein within adhesions, is one of these proteins. Its phosphorylation at serine 273 (S273) is crucial for maintaining fast adhesion assembly and disassembly. Paxillin is known to bind to a GIT1-ßPIX-PAK1 complex, which increases the local activation of the small GTPase Rac. To understand quantitatively the behaviour of this system and how it relates to adhesion assembly/disassembly, we developed a mathematical model describing the dynamics of the small GTPases Rac and Rho as determined by paxillin S273 phosphorylation. Our model revealed that the system possesses bistability, where switching between uninduced (active Rho) and induced (active Rac) states can occur through a change in rate of paxillin phosphorylation or PAK1 activation. The bistable switch is characterized by the presence of memory, minimal change in the levels of active Rac and Rho within the induced and uninduced states, respectively, and the limited regime of monostability associated with the uninduced state. These results were validated experimentally by showing the presence of bimodality in adhesion assembly and disassembly rates, and demonstrating that Rac activity increases after treating Chinese Hamster Ovary cells with okadaic acid (a paxillin phosphatase inhibitor), followed by a modest recovery after 20 min washout. Spatial gradients of phosphorylated paxillin in a reaction-diffusion model gave rise to distinct regions of Rac and Rho activities, resembling polarization of a cell into front and rear. Perturbing several parameters of the model also revealed important insights into how signalling components upstream and downstream of paxillin phosphorylation affect dynamics.
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Adhesiones Focales/metabolismo , Modelos Biológicos , Paxillin/metabolismo , Serina/metabolismo , Proteínas de Unión al GTP rac/metabolismo , Proteínas de Unión al GTP rho/metabolismo , Animales , Células CHO , Movimiento Celular , Polaridad Celular , Cricetulus , Proteínas del Citoesqueleto/metabolismo , Activación Enzimática , Inhibidores Enzimáticos/farmacología , Ácido Ocadaico/farmacología , Paxillin/química , Fosforilación , Transducción de Señal/fisiología , Quinasas p21 Activadas/metabolismoRESUMEN
Here we present a high-throughput, parallelized cytoindentor for local compression of live cells. The cytoindentor uses convex lens-induced confinement (CLiC) to indent micrometer-sized areas in single cells and/or populations of cells with submicron precision. This is accomplished using micropatterned poly(dimethylsiloxane) (PDMS) films that are adhered to a convex lens to create arrays of extrusions referred to here as "posts." These posts caused local deformation of subcellular regions without any evidence of cell lysis upon CLiC indentation. Our micropost arrays were also functionalized with glycoproteins, such as fibronectin, to both pull and compress cells under customized confinement geometries. Measurements of Chinese hamster ovary (CHO-K1) cell migration trajectories and oxidative stress showed that the CLiC device did not damage or significantly stress the cells. Our novel tool opens a new area of investigation for visualizing mechanobiology and mechanochemistry within living cells, and the high-throughput nature of the technique will streamline investigations as current tools for mechanically probing material properties and molecular dynamics within cells, such as traditional cytoindentors and atomic force microscopy (AFM), are typically restricted to single-cell manipulation.
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Técnicas Citológicas/instrumentación , Técnicas Citológicas/métodos , Microscopía Confocal/métodos , Animales , Fenómenos Biomecánicos/fisiología , Células CHO , Fenómenos Fisiológicos Celulares/fisiología , Cricetinae , Cricetulus , Dimetilpolisiloxanos/química , Diseño de Equipo , Ensayos Analíticos de Alto Rendimiento/instrumentación , Microtecnología/instrumentación , Propiedades de SuperficieRESUMEN
It is important to determine the most effective method of delivering light onto a specimen for minimal light induced damage. Assays are presented to measure photo-bleaching of fluorophores and photo-toxicity to living cells under different illumination conditions. Turning the light off during part of the experimental time reduced photo-bleaching in a manner proportional to the time of light exposure. The rate of photo-bleaching of EGFP was reduced by 9-fold with light pulsing on the micro-second scale. Similarly, in living cells, rapid line scanning resulted in reduced cell stress as measured by mitochondrial potential, rapid cell protrusion and reduced cell retraction. This was achieved on a commercial confocal laser scanning microscope, without any compromise in image quality, by using rapid laser scan settings and line averaging. Therefore this technique can be implemented broadly without any software or hardware upgrades. Researchers can use the rapid line scanning option to immediately improve image quality on fixed samples, reduce photo-bleaching for large high resolution 3D datasets and improve cell health in live cell experiments. The assays developed here can be applied to other microscopy platforms to measure and optimize light delivery for minimal sample damage and photo-toxicity.
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Luz/efectos adversos , Microscopía Confocal/métodos , Microscopía Fluorescente/métodos , Fotoblanqueo/efectos de la radiación , Animales , Células CHO , Cricetulus , Dosis de RadiaciónRESUMEN
Enantioselective nucleophilic acylation catalysis provides a simple method of determining absolute configuration for unsaturated alcohols. Extension of this technique to natural products and synthetic compounds, as well as current limitations of this approach, are also described.