Xenopus as a model organism to study heterotrimeric G-protein pathway during collective cell migration of neural crest.

Collective cell migration is essential in many fundamental aspects of normal development, like morphogenesis, organ formation, wound healing, and immune responses, as well as in the etiology of severe pathologies, like cancer metastasis. In spite of the huge amount of data accumulated on cell migration, such a complex process involves many molecular actors, some of which still remain to be functionally characterized. One of these signals is the heterotrimeric G-protein pathway that has been studied mainly in gastrulation movements. Recently we have reported that Ric-8A, a GEF for Gα proteins, plays an important role in neural crest migration in Xenopus development. Xenopus neural crest cells, a highly migratory embryonic cell population induced at the border of the neural plate that migrates extensively in order to differentiate in other tissues during development, have become a good model to understand the dynamics that regulate cell migration. In this review, we aim to provide sufficient evidence supporting how useful Xenopus model with its different tools, such as explants and transplants, paired with improved in vivo imaging techniques, will allow us to tackle the multiple signaling mechanisms involved in neural crest cell migration.

Effect of Hydrofluoric Acid Etching Time on Titanium Topography, Chemistry, Wettability, and Cell Adhesion.

Titanium implant surface etching has proven an effective method to enhance cell attachment. Despite the frequent use of hydrofluoric (HF) acid, many questions remain unresolved, including the optimal etching time and its effect on surface and biological properties. The objective of this study was to investigate the effect of HF acid etching time on Ti topography, surface chemistry, wettability, and cell adhesion. These data are useful to design improved acid treatment and obtain an improved cell response. The surface topography, chemistry, dynamic wetting, and cell adhesiveness of polished Ti surfaces were evaluated after treatment with HF acid solution for 0, 2; 3, 5, 7, or 10 min, revealing a time-dependent effect of HF acid on their topography, chemistry, and wetting. Roughness and wetting increased with longer etching time except at 10 min, when roughness increased but wetness decreased. Skewness became negative after etching and kurtosis tended to 3 with longer etching time. Highest cell adhesion was achieved after 5-7 min of etching time. Wetting and cell adhesion were reduced on the highly rough surfaces obtained after 10-min etching time.

Topographic characterisation of dental implants for commercial use.

BACKGROUND: To characterize the surface topography of several dental implants for commercial use. MATERIAL AND METHODS: Dental implants analyzed were Certain (Biomet 3i), Tissue Level (Straumann), Interna (BTI), MG-InHex (MozoGrau), SPI (Alphabio) and Hikelt (Bioner). Surface topography was ascertained using a confocal microscope with white light. Roughness parameters obtained were: Ra, Rq, Rv, Rp, Rt, Rsk and Rku. The results were analysed using single-factor ANOVA and Student-Neuman-Keuls (p<0.05) tests. RESULTS: Certain and Hikelt obtained the highest Ra and Rq scores, followed by Tissue Level. Interna and SPI obtained lower scores, and MG-InHex obtained the lowest score. Rv scores followed the same trend. Certain obtained the highest Rp score, followed by SPI and Hikelt, then Interna and Tissue Level. MG-InHex obtained the lowest scores. Certain obtained the highest Rt score, followed by Interna and Hikelt, then SPI and Tissue Level. The lowest scores were for MG-InHex. Rsk was negative (punctured surface) in the MG-InHex, SPI and Tissue Level systems, and positive (pointed surface) in the other systems. Rku was higher than 3 (Leptokurtic) in Tissue Level, Interna, MG-InHex and SPI, and lower than 3 (Platykurtic) in Certain and Hikelt. CONCLUSIONS: The type of implant determines surface topography, and there are differences in the roughness parameters of the various makes of implants for clinical use.

Effect of root planing on surface topography: an in-vivo randomized experimental trial.

BACKGROUND AND OBJECTIVE: The root surface topography exerts a major influence on clinical attachment and bacterial recolonization after root planing. In-vitro topographic studies have yielded variable results, and clinical studies are necessary to compare root surface topography after planing with current ultrasonic devices and with traditional manual instrumentation. The aim of this study was to compare the topography of untreated single-rooted teeth planed in vivo with a curette, a piezoelectric ultrasonic (PU) scraper or a vertically oscillating ultrasonic (VOU) scraper. MATERIAL AND METHODS: In a randomized experimental trial of 19 patients, 44 single-rooted teeth were randomly assigned to one of four groups for: no treatment; manual root planing with a curette; root planing with a PU scraper; or root planing with a VOU scraper. Post-treatment, the teeth were extracted and their topography was analyzed in 124 observations with white-light confocal microscopy, measuring the roughness parameters arithmetic average height, root-mean-square roughness, maximum height of peaks, maximum depth of valleys, absolute height, skewness and kurtosis. RESULTS: The roughness values arithmetic average height and root-mean-square roughness were similar after each treatment and lower than after no treatment ( p < 0.05). Absolute height was lower in the VOU group than in the untreated ( p = 0.0026) and PU (p = 0.045) groups. Surface morphology was similar after the three treatments and was less irregular than in the untreated group. Values for the remaining roughness parameters were similar among all treatment groups ( p > 0.05). CONCLUSION: Both ultrasonic devices reduce the roughness, producing a similar topography to that observed after manual instrumentation with a curette, to which they appear to represent a valid alternative.

Guía de seguimiento no invasivo del tratamiento endovascular del aneurisma de aorta abdominal / Guidelines for the non-invasive follow-up of abdominal aortic aneurysm treatment

El tratamiento endovascular del aneurisma de aorta abdominal (EVAR) representa uno de los grandes avances de la cirugía vascular en los últimos 50 años. A diferencia del tratamiento abierto, el EVAR precisa un seguimiento postoperatorio estricto. Durante el seguimiento, la imagen del dispositivo y del aneurisma son de extrema importancia para identificar pacientes en riesgo que precisan una intervención secundaria. Ello ha conducido a protocolos de seguimiento rigurosos basados en estudios con angio-TC. El empleo de estos protocolos de seguimiento tan intensivos son criticados actualmente tanto por la alta radiación administrada al paciente como por el empleo de medios de contraste nefrotóxicos. Los programas de seguimiento postoperatorios menos intensivos y basados en ultrasonidos parecen ser seguros en la mayoría de los pacientes. Proponemos un régimen de seguimiento postoperatorio del EVAR que varía la intensidad y frecuencia de los estudios de imagen postoperatorios en función de los hallazgos(AU)

Endovascular aneurysm repair (EVAR) is one of the greatest advances in vascular surgery over the past 50 years. In contrast to conventional aneurysm repair, EVAR requires stringent posoperative surveillance. Imaging of the graft and aneurysm is of utmost importance during follow-up to identify patients in need of secondary intervention. This has led to rigorous follow-up protocols based on regular CT examinations. The use of these intense follow-up protocols has recently been questioned due to the high radiation doses and the frequent use of nephrotoxic contrast agents. Less intensive follow-up based on ultrasound examination appears to be safe in the vast majority of patients. We suggest an EVAR surveillance regimen that regulates the frequency and intensity of postoperative imaging based on the outcomes(AU)

A prospective evaluation of cerebral infarction following transcervical carotid stenting with carotid flow reversal.

OBJECTIVE: Cerebral embolisation constitutes the main source of complications during transfemoral carotid artery stenting (CAS) and is associated with a high incidence of silent brain infarction. The goal of this study is to evaluate the incidence of new ischaemic cerebral lesions following transcervical CAS with carotid flow reversal for neuroprotection. MATERIALS AND METHODS: Thirty-one consecutive patients underwent transcervical CAS with carotid flow reversal. A stroke scale and diffusion-weighted magnetic resonance imaging (DW-MRI) were performed within 24 h before and after the procedure. DW-MRI studies were compared blindly by two independent neuroradiologists. New hyper-intense DW signals were interpreted as ischaemic infarcts. The progress of all patients was followed for at least 30 days following intervention. RESULTS: All procedures were technically successful. Nineteen (61%) patients were symptomatic Mean carotid flow reversal time was 22 min. There were no major adverse events at 30 days. All patients remained neurologically intact without increase in the stroke scale. Thirty subjects had paired DW-MRI studies. Post-procedural DW-MRI ischaemic infarcts were found in four (12.5%) patients, all ipsilateral to the treated hemisphere and asymptomatic. During follow-up, all stents remained patent and all patients remained stroke-free. CONCLUSIONS: These data suggest that transcervical carotid stenting with carotid flow reversal carries a low incidence of new ischaemic infarcts, significantly lower than that reported with transfemoral CAS. The transcervical approach with carotid flow reversal may improve the safety of CAS and has the potential to produce results comparable to those of carotid endarterectomy.

Influence of self-etching primer on the resin adhesion to enamel and dentin.

PURPOSE: To evaluate the shear bond strength of resin-based composite to dentin and enamel using three adhesive systems, two of them containing self-etchant primers. Wettability (contact angle measurements) of the primers of these three adhesive systems was also evaluated on superficial and deep dentin. MATERIAL AND METHODS: Contact angle measurements were performed on 30 caries-free extracted human third molars; specimens were sectioned parallel to the occlusal surface to expose superficial and deep dentin. Dentin was ground flat (600-grit SiC) under water to provide uniform surfaces. Contact angle measurements were performed to assess wettability using the Axisymmetric Drop Shape Analysis technique. In order to test the enamel bond strength, 30 extracted bovine incisors were embedded in acrylic resin and ground flat to 800-grit. The adhesives and composite resins were applied following the manufacturers' instructions. All the specimens were stored in water for 24 hrs at 37 degrees C and thermocycled (500x). Shear bond strengths were determined using a universal testing machine and the Watanabe device. For dentin bond strength testing, superficial and deep dentin was exposed in 60 third molars, by sectioning the occlusal surface immediately under the enamel-dentin junction or close to the pulp chamber. After grinding (500 grit SiC), the dentin surfaces were assigned to three groups: (1) Clearfil SE Bond (CSEB)/Clearfil AP-X resin composite. (2) Etch & Prime (E&P)/Degufill mineral resin composite. (3) Scotchbond Multi-Purpose Plus (SBMP)/Z100 resin composite. RESULTS: One-way ANOVA and Student-Newman-Keuls multiple comparisons tests showed that no differences were found between contact angles on superficial and deep dentin. CSEB and E&P, without significant differences between them, had greater mean contact angle than SBMP. On enamel, Etch & Prime resulted in the lowest bond strength, but no significant differences existed with Scotchbond Multi-Purpose were found. On dentin, Clearfil SE Bond resulted in the significantly highest bond strength; no significant differences exist between Etch & Prime and Scotchbond Multi-Purpose.

Dentin wetting by four adhesive systems.

OBJECTIVES: To evaluate the dentin wetting by four adhesive systems and to relate the wetting properties with the adhesive efficiency. METHODS: Scotch Bond Multipurpose Plus (3M), Syntac Single-Component (Vivadent), One-Step (Bisco) and Heliobond (Vivadent) were used. The substrate was superficial and deep human dentin. Roughness and water contact angle were measured before and after acid etching. Dentin wetting by resins was studied by contact angle measurements as a function of time to evaluate the spreading time. The shear bond strength was evaluated following a single plane method, and the microleakage was evaluated in Class V cavities. RESULTS: Acid etching increased dentin roughness and wettability and no differences were found between acids tested. Dentin wetting and roughness was higher on deep dentin. Dentin wetting and shear bond strength of resins was similar except for Heliobond that displayed the lowest value. Microleakage was higher on the gingival wall, and the leaking was lowest for Scotch Bond Multipurpose Plus, and maximum for Heliobond. The spreading time exceeded 30s with water-based and hydrophobic adhesives, and was lower with an acetone-based adhesive. Dentin depth had some influence on contact angle and shear bond strength: contact angles obtained with SBMP and One-Step were higher on superficial dentin, and shear bond strength for One-Step was higher on superficial dentin. Dentin wetting by resins could be correlated to shear bond strength and microleakage. SIGNIFICANCE: Dentin acid etching with different conditioners promotes similar roughness and wetting changes. On a similar substrate, the adhesion depends on the chemical and wetting characteristics of resins.