Osteogenic-angiogenic coupled response of cobalt-containing mesoporous bioactive glasses in vivo.

The incorporation of cobalt ions into the composition of bioactive glasses has emerged as a strategy of interest for bone regeneration purposes. In the present work, we have designed a set of bioactive mesoporous glasses SiO2-CaO-P2O5-CoO (Co-MBGs) with different amounts of cobalt. The physicochemical changes introduced by the Co2+ ion, the in vitro effects of Co-MBGs on preosteoblasts and endothelial cells and their in vivo behaviour using them as bone grafts in a sheep model were studied. The results show that Co2+ ions neither destroy mesoporous ordering nor inhibit in vitro bioactive behaviour, exerting a dual role as network former and modifier for CoO concentrations above 3 % mol. On the other hand, the activity of Co-MBGs on MC3T3-E1 preosteoblasts and HUVEC vascular endothelial cells is dependent on the concentration of CoO present in the glass. For low Co-MBGs concentrations (1mg/ml) cell viability is not affected, while the expression of osteogenic (ALP, RUNX2 and OC) and angiogenic (VEGF) genes is stimulated. For Co-MBGs concentration of 5 mg/ml, cell viability decreases as a function of the CoO content. In vivo studies show that the incorporation of Co2+ ions to the MBGs improves the bone regeneration activity of these materials, despite the deleterious effect that this ion has on bone-forming cells for any of the Co-MBG compositions studied. This contradictory effect is explained by the marked increase in angiogenesis that takes place inside the bone defect, leading to an angiogenesis-osteogenesis coupling that compensates for the partial decrease in osteoblast cells. STATEMENT OF SIGNIFICANCE: The development of new bone grafts implies to address the need for osteogenesis-angiogenesis coupling that allows bone regeneration with viable tissue in the long term. In this sense the incorporation of cobalt ions into the composition of bioactive glasses has emerged as a strategy of great interest in this field. Due to the potential cytotoxic effect of cobalt ions, there is an important controversy regarding the suitability of their incorporation in bone grafts. In this work, we address this controversy after the implantation of cobalt-doped mesoporous bioactive glasses in a sheep model. The incorporation of cobalt ions in bioactive glasses improves the bone regeneration ability of these bone grafts, due to enhancement of the angiogenesis-osteogenesis coupling.

Injectable mesoporous bioactive nanoparticles regenerate bone tissue under osteoporosis conditions.

The osteogenic capability of mesoporous bioactive nanoparticles (MBNPs) in the SiO2CaO system has been assessed in vivo using an osteoporotic rabbit model. MBNPs have been prepared using a double template method, resulting in spherical nanoparticles with a porous core-shell structure that has a high surface area and the ability to incorporate the anti-osteoporotic drug ipriflavone. In vitro expression of the pro-inflammatory genes NF-κB1, IL-6, TNF-α, P38 and NOS2 in RAW-264.7 macrophages, indicates that these nanoparticles do not show adverse inflammatory effects. An injectable system has been prepared by suspending MBNPs in a hyaluronic acid-based hydrogel, which has been injected intraosseously into cavitary bone defects in osteoporotic rabbits. The histological analyses evidenced that MBNPs promote bone regeneration with a moderate inflammatory response. The incorporation of ipriflavone into these nanoparticles resulted in a higher presence of osteoblasts and enhanced angiogenesis at the defect site, but without showing significant differences in terms of new bone formation. STATEMENT OF SIGNIFICANCE: Mesoporous bioactive glass nanoparticles have emerged as one of the most interesting materials in the field of bone regeneration therapies. For the first time, injectable mesoporous bioactive nanoparticles have been tested in vivo using an osteoporotic animal model. Our findings evidence that MBG nanoparticles can be loaded with an antiosteoporotic drug, ipriflavone, and incorporated in hyaluronic acid to make up an injectable hydrogel. The incorporation of MBG nanoparticles promotes bone regeneration even under osteoporotic conditions, whereas the presence of IP enhances angiogenesis as well as the presence of osteoblast cells lining in the newly formed bone. The injectable device presented in this work opens new possibilities for the intraosseous treatment of osteoporotic bone using minimally invasive surgery.

Development and assessment of an ex-vivo bench model aimed at laparoscopic ureteric reconstructive techniques.

INTRODUCTION/BACKGROUND: Reconstructive and ablative urologic techniques require special technical mastery, especially the intracorporeal suturing. OBJECTIVE: To report the subjective evaluation of a versatile ex-vivo model aimed to practice laparoscopic ureteric reconstructive techniques (LURT) on box-trainer. STUDY DESIGN: The model is a continuous portion of porcine urinary bladder ("dilated pelvis"), the vesico-ureteral joint ("stenosis") and healthy ureter. All 127 participants (n = 119 urologists and n = 8 paediatric surgeons) performed on the model laparoscopic Anderson-Hynes dismembered pyeloplasty, and then, in the animal model, different LURT procedures (ureteroneocystostomy, ureteric reimplantation and/or dismembered pyeloplasty). The model was subjectively evaluated (face and content validity), through a 12 items questionnaire, based on a Likert scale (1-5 points) and a global question (1-10 points). RESULTS: The total mean rating for 11/12 items was very high (>4points). Only one was rated under 3 points. The overall total mean rating from 1 to 10 points was very high (9.19 ± 0.82 points). In 10/12 items, expert's feedback (content validity) prevailed over non-experts (face validity). DISCUSSION/CONCLUSION: The model was highly accepted for the practice of LURT techniques. Additionally, it is cost-effective, easy to assemble, ethically considerate, and realistic.

Silicon substituted hydroxyapatite/VEGF scaffolds stimulate bone regeneration in osteoporotic sheep.

Silicon-substituted hydroxyapatite (SiHA) macroporous scaffolds have been prepared by robocasting. In order to optimize their bone regeneration properties, we have manufactured these scaffolds presenting different microstructures: nanocrystalline and crystalline. Moreover, their surfaces have been decorated with vascular endothelial growth factor (VEGF) to evaluate the potential coupling between vascularization and bone regeneration. In vitro cell culture tests evidence that nanocrystalline SiHA hinders pre-osteblast proliferation, whereas the presence of VEGF enhances the biological functions of both endothelial cells and pre-osteoblasts. The bone regeneration capability has been evaluated using an osteoporotic sheep model. In vivo observations strongly correlate with in vitro cell culture tests. Those scaffolds made of nanocrystalline SiHA were colonized by fibrous tissue, promoted inflammatory response and fostered osteoclast recruitment. These observations discard nanocystalline SiHA as a suitable material for bone regeneration purposes. On the contrary, those scaffolds made of crystalline SiHA and decorated with VEGF exhibited bone regeneration properties, with high ossification degree, thicker trabeculae and higher presence of osteoblasts and blood vessels. Considering these results, macroporous scaffolds made of SiHA and decorated with VEGF are suitable bone grafts for regeneration purposes, even in adverse pathological scenarios such as osteoporosis. STATEMENT OF SIGNIFICANCE: For the first time, the in vivo behavior of scaffolds made of silicon substituted hydroxyapatites (SiHA) has been evaluated under osteoporosis conditions. In order to optimize the bone regeneration properties of these bioceramics, 3D macroporous scaffolds have been manufactured by robocasting and implanted in osteoporotic sheep. Our experimental design shed light on the important issue of the biological response of nano-sized bioceramics vs highly crystalline bioceramics, as well as on the importance of coupling vascularization and bone growth processes by decorating SiHA scaffolds with vascular endothelial growth factor.

Mesoporous bioactive glass/ɛ-polycaprolactone scaffolds promote bone regeneration in osteoporotic sheep.

Macroporous scaffolds made of a SiO2-CaO-P2O5 mesoporous bioactive glass (MBG) and ɛ-polycaprolactone (PCL) have been prepared by robocasting. These scaffolds showed an excellent in vitro biocompatibility in contact with osteoblast like cells (Saos 2) and osteoclasts derived from RAW 264.7 macrophages. In vivo studies were carried out by implantation into cavitary defects drilled in osteoporotic sheep. The scaffolds evidenced excellent bone regeneration properties, promoting new bone formation at both the peripheral and the inner parts of the scaffolds, thick trabeculae, high vascularization and high presence of osteoblasts and osteoclasts. In order to evaluate the effects of the local release of an antiosteoporotic drug, 1% (%wt) of zoledronic acid was incorporated to the scaffolds. The scaffolds loaded with zoledronic acid induced apoptosis in Saos 2 cells, impeded osteoclast differentiation in a time dependent manner and inhibited bone healing, promoting an intense inflammatory response in osteoporotic sheep. STATEMENT OF SIGNIFICANCE: In addition to an increase in bone fragility and susceptibility to fracture, osteoporosis also hinders the clinical success of endosseous implants and grafting materials for the treatment of bone defects. For the first time, macroporous scaffolds made of mesoporous bioactive glass and ε-caprolactone have been evaluated in a sheep model that mimics the osteoporosis conditions in humans. These implants fostered bone regeneration, promoting new bone formation at both the peripheral and the inner parts of the scaffolds, showing thick trabeculae and a high vascularization degree. Our results indicate that macroporous structures containing highly bioactive mesoporous glasses could be excellent candidates for the regenerative treatment of bone defects in osteoporotic patients.

Synergistic effect of Si-hydroxyapatite coating and VEGF adsorption on Ti6Al4V-ELI scaffolds for bone regeneration in an osteoporotic bone environment.

The osteogenic and angiogenic responses to metal macroporous scaffolds coated with silicon substituted hydroxyapatite (SiHA) and decorated with vascular endothelial growth factor (VEGF) have been evaluated in vitro and in vivo. Ti6Al4V-ELI scaffolds were prepared by electron beam melting and subsequently coated with Ca10(PO4)5.6(SiO4)0.4(OH)1.6 following a dip coating method. In vitro studies demonstrated that SiHA stimulates the proliferation of MC3T3-E1 pre-osteoblastic cells, whereas the adsorption of VEGF stimulates the proliferation of EC2 mature endothelial cells. In vivo studies were carried out in an osteoporotic sheep model, evidencing that only the simultaneous presence of both components led to a significant increase of new tissue formation in osteoporotic bone. STATEMENT OF SIGNIFICANCE: Reconstruction of bones after severe trauma or tumors extirpation is one of the most challenging tasks in the field of orthopedic surgery. This scenario is even more complicated in the case of osteoporotic patients, since their bone regeneration capability is decreased. In this work we present a porous implant that promotes bone regeneration even in osteoporotic bone. By coating the implant with osteogenic bioceramics such as silicon substituted hydroxyapatite and subsequent adsorption of vascular endothelial growth factor, these implants stimulate the bone ingrowth when they are implanted in osteoporotic sheep.

Validación inicial de un programa de formación enfocado a la nefrectomía radical laparoscópica / Initial validation of a training program focused on laparoscopic radical nephrectomy

Objetivo: Evaluar un modelo de formación enfocado a la nefrectomía laparoscópica. Material y métodos: Participaron en el estudio 16 residentes, quienes realizaron un programa formativo con una sesión teórica (1 h) y práctica en simulador (7 h) y modelo animal (13 h). La primera y última nefrectomía experimental fue evaluada mediante el tiempo y la escala global Objective and Structured Assessment of Technical Skills(OSATS). Antes y después del curso realizaron 3 ejercicios en el simulador de realidad virtual LAPMentor: 1) coordinación ojo-mano; 2) coordinación mano-mano; y 3) transferencia de objetos, registrando las métricas de tiempo y movimiento. Todos los participantes rellenaron un cuestionario sobre los componentes formativos en una escala del 1 al 5. Resultados: Los participantes realizaron la última nefrectomía más rápido (p < 0,001) y con mayor puntuación OSATS (p < 0,001). Después del curso realizaron los ejercicios en LAPMentor más rápido (p < 0,05). El número de movimientos disminuyó en todos los ejercicios: 1) p < 0,001; 2) p < 0,05; y 3) p < 0,05, y la distancia recorrida en los ejercicios 1 (p < 0,05) y 2 (p < 0,05). La velocidad de movimientos aumentó en los ejercicios 2 (p < 0,001) y 3 (p < 0,001). En el cuestionario las preguntas con la mayor puntuación fueron la utilidad del entrenamiento en animal y la necesidad del mismo antes de la práctica de laparoscopia clínica (4,92 ± 0,28). Conclusiones: La combinación de simulación física y entrenamiento en animal constituye un modelo de formación efectivo para la mejora de habilidades básicas y avanzadas para la nefrectomía laparoscópica. El componente preferido por los residentes fue el modelo animal

Objective: To assess a training model focused on laparoscopic nephrectomy. Material and methods: 16 residents participated in the study, who attended a training program with a theoretical session (1 hour) and a dry (7 hours) and a wet lab (13 hours). During animal training, the first and last nephrectomies were assessed through the completion time and the global rating scale "Objective and Structured Assessment of Technical Skills" (OSATS). Before and after the course, they performed 3 tasks on the virtual reality simulator LAPMentor (1) eye-hand coordination; 2) hand-hand coordination; and 3) transference of objects), registering time and movement metrics. All participants completed a questionnaire related to the training components on a 5-point rating scale. Results: The participants performed the last nephrectomy faster (P < .001) and with higher OSATS scores (P < .001). After the course, they completed the LAPMentor tasks faster (P < .05). The number of movements decreased in all tasks (1) P < .001, 2) P < .05, and 3) P < .05), and the path length in tasks 1 (P < .05) and 2 (P < .05). The movement speeds increased in tasks 2 (P < .001) and 3 (P < .001). With regards to the questionnaire, the usefulness of the animal training and the necessity of training on them prior to their laparoscopic clinical practice were the questions with the highest score (4.92 ± .28). Conclusions: The combination of physical simulation and animal training constitute an effective training model for improving basic and advanced skills for laparoscopic nephrectomy. The component preferred by the urology residents was the animal training

Post-Renal Transplantation Bone Health in Children Evaluated by Means of Quantitative Ultrasound and Densitometry.

BACKGROUND: Patients with end-stage renal disease develop bone mineral disease, which is not always resolved after a successful renal transplantation; moreover, some of the immunosuppressants used to prevent graft rejection may affect bone health. The aim of this study was to evaluate bone health in post-renal transplantation children with the use of quantitative ultrasound (QUS) and dual-energy X-ray absorptiometry (DXA). METHODS: A descriptive study was performed in children >3 months after renal transplantation and with stable function of graft. Radial QUS and DXA (lumbar spine and total body less head (TBLH) were performed on the same day. RESULTS: A total of 35 patients were included. Mean age was 13.9 ± 3.9 years. Ten subjects had total bone density score <2 (28.5%), 4 a lumbar spine (L1-L4) Z-score of <2 (11.4%) as well as TBLH <2, and 6 subjects had a radial QUS Z-score of <2 (17.1%), and only 2 of them had concomitant Z-score <2 with the use of DXA. There was a positive non-significant correlation between TBLH and radial QUS Z-scores (Pearson r = 0.317; P = .016) and a positive significant correlation of DXA lumbar spine and radial QUS Z-scores (Pearson r = 0.452; P = .014). CONCLUSIONS: Despite a good correlation between TBLH and QUS Z-scores, there are subjects that can be considered normal by QUS and have osteopenia by TBLH DXA and vice versa; this could be due to the different bone areas evaluated.

Initial validation of a training program focused on laparoscopic radical nephrectomy. / Validación inicial de un programa de formación enfocado a la nefrectomía radical laparoscópica.

OBJECTIVE: To assess a training model focused on laparoscopic nephrectomy. MATERIAL AND METHODS: 16 residents participated in the study, who attended a training program with a theoretical session (1hour) and a dry (7hours) and a wet lab (13hours). During animal training, the first and last nephrectomies were assessed through the completion time and the global rating scale "Objective and Structured Assessment of Technical Skills" (OSATS). Before and after the course, they performed 3 tasks on the virtual reality simulator LAPMentor (1) eye-hand coordination; 2) hand-hand coordination; and 3) transference of objects), registering time and movement metrics. All participants completed a questionnaire related to the training components on a 5-point rating scale. RESULTS: The participants performed the last nephrectomy faster (P<.001) and with higher OSATS scores (P<.001). After the course, they completed the LAPMentor tasks faster (P<.05). The number of movements decreased in all tasks (1) P<.001, 2) P<.05, and 3) P<.05), and the path length in tasks 1 (P<.05) and 2 (P<.05). The movement speeds increased in tasks 2 (P<.001) and 3 (P<.001). With regards to the questionnaire, the usefulness of the animal training and the necessity of training on them prior to their laparoscopic clinical practice were the questions with the highest score (4.92±.28). CONCLUSIONS: The combination of physical simulation and animal training constitute an effective training model for improving basic and advanced skills for laparoscopic nephrectomy. The component preferred by the urology residents was the animal training.

Learning curves of basic laparoscopic psychomotor skills in SINERGIA VR simulator.

PURPOSE: Surgical simulators are currently essential within any laparoscopic training program because they provide a low-stakes, reproducible and reliable environment to acquire basic skills. The purpose of this study is to determine the training learning curve based on different metrics corresponding to five tasks included in SINERGIA laparoscopic virtual reality simulator. METHODS: Thirty medical students without surgical experience participated in the study. Five tasks of SINERGIA were included: Coordination, Navigation, Navigation and touch, Accurate grasping and Coordinated pulling. Each participant was trained in SINERGIA. This training consisted of eight sessions (R1-R8) of the five mentioned tasks and was carried out in two consecutive days with four sessions per day. A statistical analysis was made, and the results of R1, R4 and R8 were pair-wise compared with Wilcoxon signed-rank test. Significance is considered at P value <0.005. RESULTS: In total, 84.38% of the metrics provided by SINERGIA and included in this study show significant differences when comparing R1 and R8. Metrics are mostly improved in the first session of training (75.00% when R1 and R4 are compared vs. 37.50% when R4 and R8 are compared). In tasks Coordination and Navigation and touch, all metrics are improved. On the other hand, Navigation just improves 60% of the analyzed metrics. Most learning curves show an improvement with better results in the fulfillment of the different tasks. CONCLUSIONS: Learning curves of metrics that assess the basic psychomotor laparoscopic skills acquired in SINERGIA virtual reality simulator show a faster learning rate during the first part of the training. Nevertheless, eight repetitions of the tasks are not enough to acquire all psychomotor skills that can be trained in SINERGIA. Therefore, and based on these results together with previous works, SINERGIA could be used as training tool with a properly designed training program.

Validation of SINERGIA as training tool: a randomized study to test the transfer of acquired basic psychomotor skills to LapMentor.

PURPOSE: Laparoscopic surgery is commonly used in many surgical procedures but requires a learning process to develop the necessary skills. Virtual reality simulators play an essential role within the training curricula. This paper aims to determine whether training in SINERGIA VR simulator allows novice surgeons to improve their basic psychomotor laparoscopic skills. METHODS: Forty-two people participated in this study, including 28 unexperience medical students and 14 expert surgeons who developed previously more than 100 laparoscopic procedures. Medical students made a pre-training test in LapMentor II; then, they trained in SINERGIA and they finally accomplished a post-training test in LapMentor II. Experts just made one trial in LapMentor II. A statistical analysis was carried out and results of pre- and post-training tests of novices were compared with Wilcoxon signed-rank test. Pre- and post-training tests of novices were also compared with results of experts with Mann-Whitney U test. RESULTS: Most metrics provided by LapMentor II and included in this study show significant differences when comparing pre- and post-training tests of novices. Analysis of pre-training test of novices and experts results show significant differences in all analyzed metrics for all studied tasks. On the other hand, LapMentor was not able to distinguish between experts and novices after training in SINERGIA for any metric in the camera manipulation task and for some metrics of the other tasks. CONCLUSIONS: Training in SINERGIA VR simulator allows improvement of basic psychomotor laparoscpic skills and transferring them to another virtual simulator. Therefore, it could be used in laparoscopic surgery training programs.

Cloning and expression of a sorghum gene with homology to maize vp1. Its potential involvement in pre-harvest sprouting resistance.

Pre-harvest sprouting (PHS) in sorghum is related to the lack of a normal dormancy level during seed development and maturation. Based on previous evidence that seed dormancy in maize is controlled by the vp1 gene, we used a PCR-based approach to isolate two Sorghum bicolor genomic and cDNA clones from two genotypes exhibiting different PHS behaviour and sensitivity to abscisic acid (ABA). The two 699 amino acid predicted protein sequences differ in two residues at positions 341 (Gly or Cys within the repression domain) and 448 (Pro or Ser) and show over 80, 70 and 60% homology to maize, rice and oat VP1 proteins respectively. Expression analysis of the sorghum vp1 gene in the two lines shows a slightly higher level of vp1 mRNA in the embryos susceptible to PHS than in those resistant to PHS during embryogenesis. However, timing of expression was different between these genotypes during this developmental process. Whereas for the former the main peak of expression was observed at 20 days after pollination (DAP), the peak in the latter was found at later developmental stages when seed maturation was almost complete. Under favourable germination conditions and in the presence of fluridone (an inhibitor of ABA biosynthesis), sorghum vp1 mRNA showed to be consistently correlated with sensitivity to ABA but not with ABA content and dormancy.

Chromosome diversity of the genus Aotus from Colombia.

Description of six Colombian karyomorphs is completed through an extensive cytogenetic characterization of 35 Aotus (owl monkeys) specimens. The description of a new karyomorph for Colombian Aotus by chromosome on Q, G, R, and C, sequential banding is included. Pairs of karyomorphs 2 and 3 and 6 and 9 with 2n of 54, and 50, respectively, as well as karyomorphs 7 and 8 with 46 and 58 chromosomes were strongly suspected to represent different species on the grounds of large karyotypic differences. A proposal for a chromosome nomenclature of Aotus karyomorphs that aims to clarify Aotus taxonomy is presented which achieves a precise correspondence of different banding patterns, based on Q, G, R, and C sequential banding and chromosome measurements. Although our contribution is not a universal nomenclature system, unique criteria for chromosome denomination within Aotus karyomorphs are established. Previous systems of chromosome nomenclature have not successfully addressed the nomenclature of chromosomes of the same karyotype.