RESUMO
We present the results of a systematic study elucidating the role that dynamic surface tension has on the spreading and splashing dynamics of surfactant-laden droplets during the impact on hydrophobic substrates. Using four different surfactants at various concentrations, we generated a range of solutions whose dynamic surface tension were characterized to submillisecond timescales using maximum bubble-pressure tensiometry. Impact dynamics of these solutions were observed by high-speed imaging with subsequent quantitative image processing to determine the impact parameters (droplet size and speed) and dynamic wetting properties (dynamic contact angle). Droplets were slowly formed by dripping to allow the surfactants to achieve equilibrium at the free surface prior to impact. Our results indicate that while only the fastest surfactants appreciably affect the maximum spreading diameter, the droplet morphology during the initial stages of spreading is different to water for all surfactant solutions studied. Moreover, we show that surfactant-laden droplets splash more easily than pure liquid (water). Based on the association of the splashing ratio to our tensiometry measurements, we are able to predict the effective surface tension acting during splashing. These results suggest that droplet splashing characteristics are primarily defined by the stretching of the equilibrated droplet free surface.
RESUMO
The surface tension of liquid-like protein-rich biomolecular condensates is an emerging physical principle governing the mesoscopic interior organisation of biological cells. In this study, we present a method to evaluate the surface tension of model biomolecular condensates, through straighforward sessile drop measurements of capillary lengths and condensate densities. Our approach bypasses the need for characterizing condensate viscosities, which was required in previously reported techniques. We demonstrate this method using model condensates comprising two mutants of the intrinsically disordered protein Ddx4N. Notably, we uncover a detrimental impact of increased protein net charge on the surface tension of Ddx4N condensates. Furthermore, we explore the application of Scheutjens-Fleer theory, calculating condensate surface tensions through a self-consistent mean-field framework using Flory-Huggins interaction parameters. This relatively simple theory provides semi-quantitative accuracy in predicting Ddx4N condensate surface tensions and enables the evaluation of molecular organisation at condensate surfaces. Our findings shed light on the molecular details of fluid-fluid interfaces in biomolecular condensates.
Assuntos
Condensados Biomoleculares , Veias , Tensão Superficial , ViscosidadeRESUMO
BACKGROUND: Spinal cord stimulation (SCS) has been investigated as a potential therapeutic option for managing refractory symptoms in patients with Parkinson's disease (PD). OBJECTIVE: This systematic review and meta-analysis aimed to evaluate the safety and efficacy of SCS in PD. METHOD: A comprehensive literature search was conducted on PubMed and Web of Science to identify SCS studies reporting Unified Parkinson Disease Rating Scale-III (UPDRS-III) or Visual Analogue Scale (VAS) score changes in PD cohorts with at least 3 patients and a follow-up period of at least 1 month. Treatment effect was measured as the mean change in outcome scores and analyzed using an inverse variance random-effects model. The risk of bias was assessed using the Newcastle-Ottawa Scale and funnel plots. RESULTS: A total of 11 studies comprising 76 patients were included. Nine studies involving 72 patients reported an estimated decrease of 4.43 points (95% confidence interval [CI]: 2.11; 6.75, p < 0.01) in UPDRS-III score, equivalent to a 14% reduction. The axial subscores in 48 patients decreased by 2.35 points (95% CI: 1.26; 3.45, p < 0.01, 20% reduction). The pooled effect size of five studies on back and leg pain VAS scores was calculated as 4.38 (95% CI: 2.67; 6.09, p < 0.001), equivalent to a 59% reduction. CONCLUSIONS: Our analysis suggests that SCS may provide significant motor and pain benefits for patients with PD, although the results should be interpreted with caution due to several potential limitations including study heterogeneity, open-label designs, small sample sizes, and the possibility of publication bias. Further research using larger sample sizes and placebo-/sham-controlled designs is needed to confirm effectiveness.
Assuntos
Doença de Parkinson , Estimulação da Medula Espinal , Humanos , Doença de Parkinson/terapia , Doença de Parkinson/tratamento farmacológico , Estimulação da Medula Espinal/métodos , Dor/etiologiaRESUMO
BACKGROUND: Subthalamic nucleus deep brain stimulation (STN DBS) is an established therapy for Parkinson's disease (PD) patients suffering from motor response fluctuations despite optimal medical treatment, or severe dopaminergic side effects. Despite careful clinical selection and surgical procedures, some patients do not benefit from STN DBS. Preoperative prediction models are suggested to better predict individual motor response after STN DBS. We validate a preregistered model, DBS-PREDICT, in an external multicenter validation cohort. METHODS: DBS-PREDICT considered eleven, solely preoperative, clinical characteristics and applied a logistic regression to differentiate between weak and strong motor responders. Weak motor response was defined as no clinically relevant improvement on the Unified Parkinson's Disease Rating Scale (UPDRS) II, III, or IV, 1 year after surgery, defined as, respectively, 3, 5, and 3 points or more. Lower UPDRS III and IV scores and higher age at disease onset contributed most to weak response predictions. Individual predictions were compared with actual clinical outcomes. RESULTS: 322 PD patients treated with STN DBS from 6 different centers were included. DBS-PREDICT differentiated between weak and strong motor responders with an area under the receiver operator curve of 0.76 and an accuracy up to 77%. CONCLUSION: Proving generalizability and feasibility of preoperative STN DBS outcome prediction in an external multicenter cohort is an important step in creating clinical impact in DBS with data-driven tools. Future prospective studies are required to overcome several inherent practical and statistical limitations of including clinical decision support systems in DBS care.
Assuntos
Estimulação Encefálica Profunda , Doença de Parkinson , Núcleo Subtalâmico , Estimulação Encefálica Profunda/métodos , Humanos , Doença de Parkinson/cirurgia , Prognóstico , Núcleo Subtalâmico/cirurgia , Resultado do TratamentoRESUMO
The wrinkling of thin elastic objects provides a means of generating regular patterning at small scales in applications ranging from photovoltaics to microfluidic devices. Static wrinkle patterns are known to be governed by an energetic balance between the object's bending stiffness and an effective substrate stiffness, which may originate from a true substrate stiffness or from tension and curvature along the wrinkles. Here, we investigate dynamic wrinkling induced by the impact of a solid sphere onto an ultrathin polymer sheet floating on water. The vertical deflection of the sheet's center induced by impact draws material radially inward, resulting in an azimuthal compression that is relieved by the wrinkling of the entire sheet. We show that this wrinkling is truly dynamic, exhibiting features that are qualitatively different to those seen in quasistatic wrinkling experiments. Moreover, we show that the wrinkles coarsen dynamically because of the inhibiting effect of the fluid inertia. This dynamic coarsening can be understood heuristically as the result of a dynamic stiffness, which dominates the static stiffnesses reported thus far, and allows control of wrinkle wavelength.
RESUMO
Untargeted metabolomics approaches are emerging as powerful tools for the quality evaluation and authenticity of food and beverages and have been applied to wine science. However, most fail to report the method validation, quality assurance and/or quality control applied, as well as the assessment through the metabolomics-methodology pipeline. Knowledge of Mexican viticulture, enology and wine science remains scarce, thus untargeted metabolomics approaches arise as a suitable tool. The aim of this study is to validate an untargeted HS-SPME-GC-qTOF/MS method, with attention to data processing to characterize Cabernet Sauvignon wines from two vineyards and two vintages. Validation parameters for targeted methods are applied in conjunction with the development of a recursive analysis of data. The combination of some parameters for targeted studies (repeatability and reproducibility < 20% RSD; linearity > 0.99; retention-time reproducibility < 0.5% RSD; match-identification factor < 2.0% RSD) with recursive analysis of data (101 entities detected) warrants that both chromatographic and spectrometry-processing data were under control and provided high-quality results, which in turn differentiate wine samples according to site and vintage. It also shows potential biomarkers that can be identified. This is a step forward in the pursuit of Mexican wine characterization that could be used as an authentication tool.
Assuntos
VinhoRESUMO
Abnormalities in the origin of vertebral arteries are relatively uncommon, but extremely rare when this abnormality happens on both sides. We present an anatomic variation in which both vertebral arteries came from the proximal descending thoracic aorta beyond the left subclavian artery with no other supra-aortic vessels accompanying the abnormality. The right vertebral artery took a retro-oesophageal course (lusoria artery), while the right and the left vertebral arteries enter the transverse foramina at the 7th cervical vertebra. From an embryological point of view, and overall controversial, this anomaly can be explained by the bilateral persistence of the 8th intersegmental artery as the origin of vertebral artery, instead of the dorsal segment of the 7th intersegmental artery being the origin, which is normally the case. The adequate identification of vertebral artery anomalies in complementary explorations is very important to avoid misdiagnosed vertebral occlusions or unexpected vertebral artery injuries during supra-aortic trunks, thyroid, and oesophagus open surgeries, among others, or even over the course of endovascular procedures.
Assuntos
Artéria Subclávia , Artéria Vertebral , Aorta , Aorta Torácica/anormalidades , Aorta Torácica/diagnóstico por imagem , Tronco Braquiocefálico , Vértebras Cervicais/irrigação sanguínea , Humanos , Artéria Subclávia/anormalidades , Artéria Subclávia/diagnóstico por imagem , Artéria Vertebral/anormalidades , Artéria Vertebral/diagnóstico por imagemRESUMO
Many proofs of concept have demonstrated the potential of microfluidics in cell biology. However, the technology remains inaccessible to many biologists, as it often requires complex manufacturing facilities (such as soft lithography) and uses materials foreign to cell biology (such as polydimethylsiloxane). Here, we present a method for creating microfluidic environments by simply reshaping fluids on a substrate. For applications in cell biology, we use cell media on a virgin Petri dish overlaid with an immiscible fluorocarbon. A hydrophobic/fluorophilic stylus then reshapes the media into any pattern by creating liquid walls of fluorocarbon. Microfluidic arrangements suitable for cell culture are made in minutes using materials familiar to biologists. The versatility of the method is demonstrated by creating analogs of a common platform in cell biology, the microtiter plate. Using this vehicle, we demonstrate many manipulations required for cell culture and downstream analysis, including feeding, replating, cloning, cryopreservation, lysis plus RT-PCR, transfection plus genome editing, and fixation plus immunolabeling (when fluid walls are reconfigured during use). We also show that mammalian cells grow and respond to stimuli normally, and worm eggs develop into adults. This simple approach provides biologists with an entrée into microfluidics.
Assuntos
Dispositivos Lab-On-A-Chip , Técnicas Analíticas Microfluídicas/instrumentação , Técnicas Analíticas Microfluídicas/métodos , Biologia Celular/instrumentação , Técnicas Citológicas/instrumentação , Técnicas Citológicas/métodosRESUMO
We investigate the effects of surface stiffness on the air cushioning at the bottom of a liquid drop impacting onto a soft solid and the resulting entrapment of a central bubble. This was achieved using ultra-high-speed interferometry at 5 million frames per second and spatial resolution of 1.05 µm per pixel. The soft solid delays the effects of gas compressibility resulting in much larger air discs than corresponding impacts onto rigid surfaces. Using an effective impact velocity equal to half of the actual impact velocity brings the soft solid scaling behavior better in line with rigid substrate scaling. We also observe extended gliding of the drop as it initially avoids contact with the surface spreading over a thin layer of air and investigate the threshold velocity for the transition from gliding to ring contact. Such extended gliding layers have previously been seen for high-viscosity drop impacts, but not for low-viscosity liquids at the impact velocities used herein.
RESUMO
BACKGROUND: Strong agreement exists concerning the standards of pathologic reporting for total mesorectal excision and complete mesocolic excision. It represents a quality standard that correlates with survival. However, no agreed standards of reporting are available to define D3 lymphadenectomy for right colectomy. OBJECTIVE: The purpose of this study was to define anatomopathological standards of specimen quality obtained from the surgical specimen when an oncologic right hemicolectomy with D3 lymphadenectomy has been correctly performed. DESIGN: This study was conducted in 2 different phases. The first part consisted of a cadaver-based study of right colon anatomy, and the second part consisted of a prospective assessment of a series of surgical specimens obtained after right hemicolectomy for cancer. SETTINGS: The anatomic phase of the study was performed in collaboration with the University of Valencia Department of Anatomy and Embryology. The second part was performed at a colorectal unit of a tertiary hospital. PATIENTS: Seventeen cadavers were used for the first phase, and 65 surgical specimens were examined for the second part of the study. MAIN OUTCOME MEASURES: In each specimen, the pathologists looked for anatomic structures defined as markers of quality standards of the D3 lymphadenectomy during the first phase. Specimens were classified as complete, partial, and incomplete D3 lymphadenectomy. RESULTS: Twenty percent of specimens were classified as incomplete D3 lymphadenectomy, 31% as partial, and 49% as complete. A median number of 14 (6-64), 22 (11-47), and 29 (14-55) lymph nodes were isolated (p = 0.01). Similarly, the median numbers of lymph nodes isolated in the area of D3 lymphadenectomy were 0 in incomplete, 1 (0-5) in Partial, and 3 (0-8) in Complete D3 lymphadenectomy specimens (p = 0.0001). LIMITATIONS: A large multicenter study with adequate power is needed. CONCLUSIONS: We propose the right mesocolic sail and trunk of superior right colic vein as new and reproducible anatomopathologic standards of D3 lymphadenectomy in oncologic right hemicolectomy. See Video Abstract at http://links.lww.com/DCR/B149. PROPUESTA PARA NUEVOS ESTÁNDARES HISTOPATOLÓGICOS EN LA LINFADENECTOMÍA D3 EN EL CÁNCER DE COLON DERECHO: LA VELA MESOCÓLICA Y LA VENA CÓLICA DERECHA SUPERIOR: Existe un claro acuerdo sobre los estándares de calidad patológicos para la escisión total del mesorrecto y la escisión completa del mesocolon. Son considerados "estándar de calidad" que se correlaciona con la supervivencia. Sin embargo, no se dispone de estándares de calidad para definir la linfadenectomía D3, en la colectomía derecha.Definir los estándares anatomopatológicos de calidad obtenidos de una muestra quirúrgica, cuando se ha realizado correctamente una hemicolectomía derecha oncológica, con linfadenectomía D3.Dos fases diferentes. La primera parte consistió en un estudio basado en la anatomía del colon derecho, realizado en cadáveres, y la segunda parte consistió en una evaluación prospectiva de una serie de muestras quirúrgicas obtenidas después de la hemicolectomía derecha para cáncer.La fase anatómica del estudio se realizó en colaboración con el Departamento de Anatomía y Embriología de la Universidad de Valencia. La segunda parte se realizó en la Unidad Colorrectal de un hospital terciario.Se utilizaron diecisiete cadáveres para la primera fase y se examinaron 65 muestras quirúrgicas para la segunda parte del estudio.En cada muestra, los patólogos buscaron estructuras anatómicas definidas, como marcadores de los estándares de calidad de la linfadenectomía D3, durante la primera fase. Las muestras se clasificaron como linfadenectomía D3 completa, parcial e incompleta.El veinte por ciento de las muestras se clasificaron como "Linfadenectomía D3 Incompleta", el 31% como "Parcial" y el 49% como "Completa." Se aisló una media de 14 (6-64), 22 (11-47) y 29 (14-55) ganglios linfáticos respectivamente (p = 0,01). Del mismo modo, el número medio de ganglios linfáticos aislados en el área de la linfadenectomía D3 fue 0 en "Incompleta", 1 (0-5) en "Parcial" y 3 (0-8) en muestras de "Linfadenectomía D3 Completa" (p = 0,0001).Se necesita un estudio multicéntrico con potencia adecuada.Proponemos la vela mesocólica derecha y el tronco de la vena cólica derecha superior, como estándares anatomopatológicos nuevos y reproducibles de linfadenectomía D3, en hemicolectomía derecha oncológica. Consulte Video Resumen en http://links.lww.com/DCR/B149.
Assuntos
Pontos de Referência Anatômicos , Colectomia/métodos , Neoplasias do Colo/cirurgia , Laparoscopia/métodos , Excisão de Linfonodo/métodos , Linfonodos/patologia , Veias Mesentéricas/cirurgia , Estadiamento de Neoplasias , Idoso , Idoso de 80 Anos ou mais , Cadáver , Neoplasias do Colo/diagnóstico , Neoplasias do Colo/secundário , Feminino , Seguimentos , Humanos , Linfonodos/cirurgia , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Estudos ProspectivosRESUMO
AIM: The aim of this study was to describe all the possible approaches for laparoscopic splenic flexure mobilization (SFM), each suitable for specific situations, and create an illustrated system to show SFM approaches in an easy and practical way to make it easy to learn and teach. METHODS: Two different phases. First part: Cadaver-based study of the colonic splenic flexure anatomy. In order to demonstrate the different approaches, a balloon was placed through the colonic hepatic flexure in the lesser sac without sectioning any of the fixing ligaments of the splenic flexure. Second part: A real case series of laparoscopic SFM. RESULTS: First part: 11 cadavers were dissected. Five potential approaches to SFM were found: anterior, trans-omentum, lateral, medial infra-mesocolic, and medial trans-mesocolic. The illustrative system developed was named: Splenic Flexure "Box"(SFBox). Second part: One of the types of SFM described in first part was used in five patients with colorectal cancer. Each laparoscopic approach to the splenic flexure was illustrated in a video accompanied by illustration aids delineating the access. CONCLUSION: With the cadaver dissection and subsequent demonstration in real-life laparoscopic surgery, we have shown five types of laparoscopic splenic flexure mobilization. The Splenic Flexure "Box" is a useful way to learn and teach this surgical maneuver.
Assuntos
Colectomia/métodos , Colo Transverso/anatomia & histologia , Colo Transverso/cirurgia , Neoplasias Colorretais/cirurgia , Laparoscopia/métodos , Cadáver , Colectomia/educação , Dissecação , Feminino , Humanos , Laparoscopia/educação , Masculino , Mesocolo/cirurgiaRESUMO
We present the clinical case of a 60-year-old woman complained of dyspnea on exertion. Echocardiogram showed a giant mass in the right ventricle (RV) with obstruction to the outflow tract. Thorax computed tomography confirmed a mass of greater than 60 mm infiltrating RV and causing severe stenosis in the pulmonary artery, with severe pericardial effusion. Cardiac surgery was performed for tumor resection and pulmonary root replacement with a biological valved conduit. Histological analysis diagnosed a poorly differentiated large-cell neuroendocrine carcinoma. The patient had no immediate postoperative complications and has completed radiotherapy at a 9-month follow-up.
Assuntos
Carcinoma Neuroendócrino/diagnóstico por imagem , Carcinoma Neuroendócrino/cirurgia , Procedimentos Cirúrgicos Cardíacos/métodos , Ecocardiografia , Neoplasias Cardíacas/diagnóstico por imagem , Neoplasias Cardíacas/cirurgia , Ventrículos do Coração/diagnóstico por imagem , Ventrículos do Coração/cirurgia , Artéria Pulmonar/diagnóstico por imagem , Artéria Pulmonar/cirurgia , Tomografia Computadorizada por Raios X , Implante de Prótese Vascular/métodos , Carcinoma Neuroendócrino/complicações , Carcinoma Neuroendócrino/patologia , Constrição Patológica/diagnóstico por imagem , Constrição Patológica/etiologia , Constrição Patológica/cirurgia , Feminino , Neoplasias Cardíacas/complicações , Neoplasias Cardíacas/patologia , Ventrículos do Coração/patologia , Humanos , Pessoa de Meia-Idade , Derrame Pericárdico/diagnóstico por imagem , Derrame Pericárdico/etiologia , Artéria Pulmonar/patologia , Índice de Gravidade de Doença , Resultado do TratamentoRESUMO
In the present study we evaluated the putative cases of sympatric speciation in the genus Herichthys by studying the variation in head shape using principal component analysis, phylomorphospace and reconstructions of the ancestral states of feeding preferences. Herichthys includes both allopatric and sympatric sister species, as well as sympatric unrelated species and thus offers great potential for evolutionary studies of putatively sympatric speciation. Herichthys is the northernmost group of cichlids in America and one of the most ecologically disparate genera within Middle American cichlids. Fifteen anatomical points were recorded on the heads of 293 specimens of the 11 species recognized within the genus. The results show that in spite of having wide variation in consumed diets, most species of Herichthys are close in morphospace. However, morphological variation was great among the two pairs of sympatric sister species in agreement with the suggested sympatric model of speciation.
Assuntos
Biodiversidade , Ciclídeos/anatomia & histologia , Ciclídeos/classificação , Comportamento Alimentar , Cabeça , Simpatria , Animais , Evolução Biológica , Especiação Genética , Cabeça/anatomia & histologia , FilogeniaRESUMO
In the pathophysiology and progression of pelvic organ prolapse (POP), it has been demonstrated that there is a reorganisation of the muscularis propria of the anterior vaginal wall due to a phenotypic smooth muscle cell to myofibroblast switch. An abnormal deposition of collagen type III seems to be influenced by the involvement of advanced glycation end-products. The aim of the present study was to evaluate the hypothesis that this connective tissue remodelling could also be associated with neurovascular alterations of the muscularis in women with POP compared with control patients. We examined 30 women with POP and 10 control patients treated for uterine fibromatosis. Immunohistochemical analysis, using glial fibrillary acidic protein, S-100 protein, receptor tyrosine kinase, neurofilament and α-smooth muscle actin antibodies, was performed. S-100, receptor tyrosine kinase and neurofilament were also evaluated using Western blot analysis. We observed a decrease in all neurovascular-tested markers in nerve bundles, ganglia and interstitial cells of Cajal from POP samples as compared with controls. Even if the processes responsible for these morphological alterations are still not known, it is conceivable that collagen III deposition in the anterior vaginal wall affects not only the architecture of the muscle layer but could also modify the intramuscular neurovascularisation and account for an alteration of the neuromuscular plasticity of the layer.
Assuntos
Tecido Conjuntivo/patologia , Músculos/patologia , Prolapso de Órgão Pélvico/etiologia , Vagina/patologia , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Humanos , Pessoa de Meia-Idade , Músculos/irrigação sanguínea , Músculos/inervação , Prolapso de Órgão Pélvico/patologia , Vagina/irrigação sanguínea , Vagina/inervaçãoRESUMO
Spinal cord stimulation (SCS) applied between T8 and T11 segments has been shown to be effective for the treatment of chronic pain of the lower back and limbs. However, the mechanism of the analgesic effect at these medullary levels remains unclear. Numerous studies relate glial cells with development and maintenance of chronic neuropathic pain. Glial cells are electrically excitable, which makes them a potential therapeutic target using SCS. The aim of this study is to report glia to neuron ratio in thoracic segments relevant to SCS, as well as to characterize the glia cell population at these levels. Dissections from gray and white matter of posterior spinal cord segments (T8, T9, intersection T9/T10, T10 and T11) were obtained from 11 human cadavers for histological analyses. Neuronal bodies and glial cells (microglia, astrocytes and oligodendrocytes) were immunostained, microphotographed and counted using image analysis software. Statistical analyses were carried out to establish significant differences of neuronal and glial populations among the selected segments, between the glial cells in a segment, and glial cells in white and gray matter. Results show that glia to neuron ratio in the posterior gray matter of the human spinal cord within the T8-T11 vertebral region is in the range 11 : 1 to 13 : 1, although not significantly different among vertebral segments. Glia cells are more abundant in gray matter than in white matter, whereas astrocytes and oligodendrocytes are more abundant than microglia (40 : 40 : 20). Interestingly, the population of oligodendrocytes in the T9/T10 intersection is significantly larger than in any other segment. In conclusion, glial cells are the predominant bodies in the posterior gray and white matter of the T8-T11 segments of the human spinal cord. Given the crucial role of glial cells in the development and maintenance of neuropathic pain, and their electrophysiological characteristics, anatomical determination of the ratio of different cell populations in spinal segments commonly exposed to SCS is fundamental to understand fully the biological effects observed with this therapy.
Assuntos
Neuroglia/citologia , Neurônios/citologia , Estimulação da Medula Espinal , Medula Espinal/citologia , Idoso , Idoso de 80 Anos ou mais , Contagem de Células , Feminino , Substância Cinzenta/citologia , Humanos , Masculino , Pessoa de Meia-Idade , Vértebras Torácicas , Substância Branca/citologiaRESUMO
In this Letter, we study the splashing behavior of droplets upon impact onto a variety of substrates with different wetting properties, ranging from hydrophilic to superhydrophobic surfaces. In particular, we study the effects of the dynamic contact angle on splashing. The experimental approach uses high-speed imaging and image analysis to recover the apparent contact angle as a function of the spreading speed. Our results show that neither the Capillary number nor the so-called splashing parameter are appropriate to characterize the splashing behavior under these circumstances. However, we show that the maximum dynamic advancing contact angle and the splashing ratio ß adequately characterize the splashing behavior.
RESUMO
We study the dynamics of droplets driven by a gradient of curvature, as may be achieved by placing a drop on the surface of a cone. The curvature gradient induces a pressure gradient within the drop, which in turn leads to spontaneous propulsion of the droplet. To investigate the resulting driving force we perform a series of experiments in which we track a droplet's displacement, s, from the apex of a cone whose surface is treated to exhibit near-zero pinning effects. We find an s â¼ t1/4 scaling at sufficiently late times t. To shed light upon these dynamics, we perform an asymptotic calculation of the equilibrium shape of a droplet on a weakly curved cylinder, deriving the curvature-induced force responsible for its propulsion. By balancing this driving force with viscous dissipation, we recover a differential equation for the droplet displacement, whose predictions are found to be in good agreement with our experimental results.
RESUMO
BACKGROUND: The fusion fascia of Toldt is a well-known landmark used by colorectal surgeons. On the contrary, the fusion fascia of Fredet (the plane between the ascending mesocolon and the visceral duodenal-pancreatic peritoneum) still remains a neglected embryological structure. Aim of this study was to provide an anatomic description of this fascia and its application to minimally invasive D3-lymphadenectomy (D3-L) and complete mesocolic excision (CME) for right colon cancer. METHODS: First phase: Cadaveric dissection and anatomic description of the fascia of Fredet. Second phase: prospective evaluation of its surgical application in a consecutive series of laparoscopic right hemicolectomies with CME and D3-L at a tertiary hospital. RESULTS: The fascia of Fredet was identified and dissected in one fresh and two formalin-fixed cadavers. The trunk of Henle and the medial border of the superior mesenteric vein defined the medial limit of this embryologic plane. Seventeen patients were operated on. Laparoscopic dissection of the fascia of Fredet was possible in every patient. Median operative time was 210 (120-380) min. There were no major postoperative complications. All cases were adenocarcinomas, except one adenomatous polyp. T stage was Tis in three, T2 in two, T3 in seven, and T4 in five patients. Median number of harvested lymph nodes was 24 (9-39). Lymphatic invasion was found in six patients. All resections were classified as satisfactory mesocolic excision and R0. Median postoperative length of stay was 6 (4-20) days. Median follow-up time was 28 (16-41) months. Local and distal recurrence rate was 0. CONCLUSION: The fusion fascia of Fredet is useful to achieve CME and D3-L in right colon cancers with reduced risk of intraoperative complications. This structure is particularly suitable for minimally invasive surgery; therefore, we encourage awareness of the fascia of Fredet by colorectal surgeons.
Assuntos
Adenocarcinoma , Colectomia/métodos , Neoplasias do Colo , Fáscia , Laparoscopia/métodos , Excisão de Linfonodo/métodos , Mesocolo , Adenocarcinoma/patologia , Adenocarcinoma/cirurgia , Neoplasias do Colo/patologia , Neoplasias do Colo/cirurgia , Dissecação/métodos , Fáscia/anatomia & histologia , Fáscia/transplante , Feminino , Humanos , Masculino , Mesocolo/patologia , Mesocolo/cirurgia , Pessoa de Meia-Idade , Avaliação de Processos e Resultados em Cuidados de Saúde , Peritônio/cirurgia , Estudos ProspectivosRESUMO
Nexobrid is a new resource for debridement that has emerged in recent years and is gaining relevance in the treatment of all kinds of thermal injuries. This product is an ointment (formed with a mixture of pineapple-derived enzymes enriched with bromelain) that is directly applied over the burn. With a single application, it performs a burned tissue-specific debridement in less than 4 hr, leaving a vital and completely debrided wound bed. In this article, we describe our experience with this product, and through a representative case, we explain the management of these patients in our Burns unit in consonance with national and international consensus.
Assuntos
Bromelaínas/administração & dosagem , Queimaduras/tratamento farmacológico , Desbridamento/métodos , Adulto , Bromelaínas/farmacologia , Queimaduras/classificação , Queimaduras/enzimologia , Traumatismos do Pé/tratamento farmacológico , Humanos , Traumatismos da Perna/tratamento farmacológico , MasculinoRESUMO
Given their high rate of complications, radical surgical procedures of anorectal and gynecological tumors require a reliable and individualized reconstruction. The latter is influenced by the frequent indication of adjuvant chemo/radiotherapy that they present. We describe the case of a patient with medical history of vulvar carcinoma that required radical surgery and bilateral inguinal lymphadenectomy. Because of the stage of the tumor, the application of postoperative radiotherapy was clinically indicated; however, after surgery, the patient developed bilateral inguinal ulcers that made postoperative radiotherapy application impossible. Using a radical surgical approach in combination with postoperative radiotherapy increases survival in patients with these types of tumors. Therefore, delaying its use because of wound complications or inadequate reconstruction cannot be justified. The pedicled abdominal rectus flap is an excellent option for this purpose in patients with moderate- to large-sized defects.