The scope and sequence of growth factor delivery for vascularized bone tissue regeneration.

Bone regeneration is a complex process, that in vivo, requires the highly coordinated presentation of biochemical cues to promote the various stages of angiogenesis and osteogenesis. Taking inspiration from the natural healing process, a wide variety of growth factors are currently being released within next generation tissue engineered scaffolds (in a variety of ways) in order to heal non-union fractures and bone defects. This review will focus on the delivery of multiple growth factors to the bone regeneration niche, specifically 1) dual growth factor delivery signaling and crosstalk, 2) the importance of growth factor timing and temporal separation, and 3) the engineering of delivery systems that allow for temporal control over presentation of soluble growth factors. Alternative methods for growth factor presentation, including the use of gene therapy and platelet-rich plasma scaffolds, are also discussed.

Towards a minimally invasive sampling tool for high resolution tissue analytical mapping.

Multiple spatial mapping techniques of biological tissues have been proposed over the years, but all present limitations either in terms of resolution, analytical capacity or invasiveness. Ren et al (2015 Nanotechnology 26 284001) propose in their most recent work the use of a picosecond infrared laser (PIRL) under conditions of ultrafast desorption by impulsive vibrational excitation (DIVE) to extract small amounts of cellular and molecular components, conserving their viability, structure and activity. The PIRL DIVE technique would then work as a nanobiopsy with minimal damage to the surrounding tissues, which could potentially be applied for high resolution local structural characterization of tissues in health and disease with the spatial limit determined by the laser focus.

Poroelastic response of articular cartilage by nanoindentation creep tests at different characteristic lengths.

Nanoindentation is an experimental technique which is attracting increasing interests for the mechanical characterization of articular cartilage. In particular, time dependent mechanical responses due to fluid flow through the porous matrix can be quantitatively investigated by nanoindentation experiments at different penetration depths and/or by using different probe sizes. The aim of this paper is to provide a framework for the quantitative interpretation of the poroelastic response of articular cartilage subjected to creep nanoindentation tests. To this purpose, multiload creep tests using spherical indenters have been carried out on saturated samples of mature bovine articular cartilage achieving two main quantitative results. First, the dependence of indentation modulus in the drained state (at equilibrium) on the tip radius: a value of 500 kPa has been found using the large tip (400 µm radius) and of 1.7 MPa using the smaller one (25 µm). Secon, the permeability at microscopic scale was estimated at values ranging from 4.5×10(-16) m(4)/N s to 0.1×10(-16) m(4)/N s, from low to high equivalent deformation. Consistently with a poroelastic behavior, the size-dependent response of the indenter displacement disappears when characteristic size and permeability are accounted for. For comparison purposes, the same protocol was applied to intrinsically viscoelastic homogeneous samples of polydimethylsiloxane (PDMS): both indentation modulus and time response have been found size-independent.

Effect of dose and exposure to diatomaceous earth on different insects in stored corn / Efeito da dose e exposição à terra de diatomácea de diferentes insetos em milho armazenado

Sitophilus zeamais and Tribolium castaneum are important insect pests of stored grain and their damage corresponds to approximately 25% of post-harvest losses in Brazil. The methods used for the control of these pests notably include the use of post-harvest inert dusts. Therefore, the objective was to assess the mortality of adult S. zeamais and T. castaneum with the use of diatomaceous earth (DE) at different dosages and durations. The treatments with diatomaceous earth were 1,000 and 2,000 GT-1 and control (no application). Insects (10 each species) were placed in 300-ml plastic containers containing 100 g of corn kernels with different moisture contents (12, 14 and 16% wb). Infestations occurred 1 hour, 10 and 20 days after the application of TD. Mortality was evaluated at 30 and 60 days. There were five replicates per treatment. There was a higher mortality for the species S. zeamais than for T. castaneum, and this morality rate increased in direct relation to insect exposure time. It was concluded that T. castaneum has greater tolerance and that the more time the insects are in contact with treated grain the greater the mortality.

Sitophilus zeamais e Tribolium castaneum são importantes insetos-pragas de grãos armazenados e seus danos correspondem a aproximadamente 25% das perdas na pós-colheita do Brasil. Entre as formas de controle destaca-se o uso de pós-inertes. Sendo assim, o objetivo deste trabalho foi avaliar a mortalidade de adultos de S. zeamais e T. castaneum com uso de terra de diatomácea (TD) em diferentes dosagens e períodos de exposição. Os tratamentos com terra de diatomácea foram: 1.000 e 2.000 g.t-1 e controle (sem aplicação). Os insetos (10 de cada espécie) foram acondicionados em recipientes plásticos de 300 mL, contendo 100 g de grãos de milho com diferentes umidades (12, 14 e 16% b.u.). As infestações ocorreram 1 hora, 10 e 20 dias após a aplicação da TD. Avaliou-se a mortalidade aos 30 e 60 dias. Foram realizadas cinco repetições/tratamento. Obteve-se maior mortalidade para a espécie S. zeamais do que T. castaneum, sendo que ela aumenta conforme o tempo de exposição dos insetos. Conclui-se que a espécie T. castaneum apresenta maior tolerância e que quanto maior tempo os insetos estiverem em contato com grãos tratados maior será a mortalidade.

Gender-related differences in patients undergoing mechanical aortic valve replacement with the CarboMedics valve.

AIM: The aim of this paper was to evaluate gender-related differences in patients undergoing mechanical aortic valve replacement with the CarboMedics valve. METHODS: During a 20 year period, 629 patients (median age 60 years) underwent mechanical aortic valve replacement with the CarboMedics valve. Of these, 215 patients were female (34%). The median follow-up for the entire cohort was 10.2 ± 6.2 years. RESULTS: In-hospital mortality for the entire cohort was 9% (male 7.3% vs. female 11.0%, P=0.005). Cox regression analysis revealed redo-surgery (HR=2.35, CI 1.35-4.08), LVEF<30% (HR=2.31, CI 1.36-3.93), age (HR=1.60, CI 1.27-2.02), as well as female gender (HR=2.07, CI 1.28-3.35) as independent predictors of survival. For male gender LVEF<30% (HR=2.47, CI 1.23-4.93) and age (HR=1.75, CI 1.25-2.43) were independent predictors of survival. For female gender, additional CABG (HR=2.15, CI 1.08-4.28), redo surgery (HR=3.64, CI 1.78-7.46) as well as age (HR=1.48, CI 1.06-2.06) were independent predictors of survival. CONCLUSION: Gender per se is an independent risk factor of survival after mechanical aortic valve replacement. Severely impaired LVEF independently predicts survival in males whereas additional CABG and redo surgery do in females. Age affects survival in both sexes. These findings may serve as a basis for further improving gender related outcome.

Value and pitfalls of neurophysiological monitoring in thoracic and thoracoabdominal aortic replacement and endovascular repair.

BACKGROUND: The aim of our study was to analyze the neurophysiological monitoring method with regard to its potential problems during thoracic and thoracoabdominal aortic open or endovascular repair. Furthermore, preventive strategies to the main pitfalls with this method were developed. METHODS: Between 11/2000 and 05/2007 in 97 cases open surgery or endovascular stentgraft-implantation was performed on the thoracic or thoracoabdominal aorta. Intraoperatively, neurophysiologic motor- and somatosensory-evoked potentials were monitored. RESULTS: Our cases were divided into four groups: event-free patients with normal potentials (A, 63 cases), with correlation of modified evoked potentials and neurological outcome (B, 14 cases), false-positive or false-negative results (C, 4 cases), and medication interaction or technical issues (D, 16 cases). We observed a sensitivity of 93 % and a specificity of 96 % for the neurophysiological monitoring. CONCLUSIONS: Monitoring spinal cord function during surgical and endovascular interventions on the thoracic and thoracoabdominal aorta is necessary. It can be made more effective by precisely analyzing the interference factors of the neurophysiological monitoring method itself. Successful strategies of immediate troubleshooting could be identified.

Bail-out visceral bypass grafting for acute intestinal ischemia after endovascular stent-graft placement in a complicated type B dissection.

We report on the case of a 35-year-old male who underwent emergency stent-graft placement in March 2007 due to a complicated type B dissection. One week after this procedure the patient developed critical visceral malperfusion. Subsequently, autologous iliaco-mesenteric as well as iliaco-hepatic bypass grafting was performed. At 6-month follow-up, aortic remodelling has occurred and visceral perfusion is regular.