The application of platelet rich fibrin in patients presenting with osteonecrosis of the jaw: A systematic literature review

The aim of this systematic literature review was to summarise the available evidence regarding the administration of platelet rich fibrin (PRF) in patients diagnosed with osteonecrosis of the jaw (ONJ). A PRISMA-conform sys- tematic literature review was conducted using a PICO-defined search strategy. MEDLINE was accessed and hits published before February 2020 were reviewed. All studies reporting on intraoperative administration of PRF into an osseous defect in patients presenting with ONJ were included. Eligibility of the studies was assessed by two independent reviewers according to prespecified criteria. Sixteen studies described the application of PRF for treatment of ONJ in 166 patients. Follow-up periods ranged from 30 to 1560 days. There was large heterogeneity regarding patient details and perioperative management. The only randomised controlled study (RCT) included suggested modest superiority in early recovery, infection rate and reported pain. No adverse events related to PRF were reported in any of the studies. The evidence regarding relative merits of PRF application versus standard of care in patients with ONJ is low. Current evidence is limited by small, non-consecutive patient samples and lack of a randomised control group. Because some observational reports and one RCT suggested improvements of early recovery, further studies are neede

Comparative release of growth factors from PRP, PRF, and advanced-PRF

OBJECTIVES The use of platelet concentrates has gained increasing awareness in recent years for regenerative procedures in modern dentistry. The aim of the present study was to compare growth factor release over time from platelet-rich plasma (PRP), platelet-rich fibrin (PRF), and a modernized protocol for PRF, advanced-PRF (A-PRF). MATERIALS AND METHODS Eighteen blood samples were collected from six donors (3 samples each for PRP, PRF, and A-PRF). Following preparation, samples were incubated in a plate shaker and assessed for growth factor release at 15 min, 60 min, 8 h, 1 day, 3 days, and 10 days. Thereafter, growth factor release of PDGF-AA, PDGF-AB, PDGF-BB, TGFB1, VEGF, EGF, and IGF was quantified using ELISA. RESULTS The highest reported growth factor released from platelet concentrates was PDGF-AA followed by PDGF-BB, TGFB1, VEGF, and PDGF-AB. In general, following 15-60 min incubation, PRP released significantly higher growth factors when compared to PRF and A-PRF. At later time points up to 10 days, it was routinely found that A-PRF released the highest total growth factors. Furthermore, A-PRF released significantly higher total protein accumulated over a 10-day period when compared to PRP or PRF. CONCLUSION The results from the present study indicate that the various platelet concentrates have quite different release kinetics. The advantage of PRP is the release of significantly higher proteins at earlier time points whereas PRF displayed a continual and steady release of growth factors over a 10-day period. Furthermore, in general, it was observed that the new formulation of PRF (A-PRF) released significantly higher total quantities of growth factors when compared to traditional PRF. CLINICAL RELEVANCE Based on these findings, PRP can be recommended for fast delivery of growth factors whereas A-PRF is better-suited for long-term release

Metabolite concentration changes during motor activation using functional Magnetic Resonance Spectroscopy (fMRS) at 7T

Functional MR spectroscopy (fMRS) allows to investigate the metabolic response of the brain to a physiological stimulation, by acquiring continuously MR spectra during a functional task, and provides direct insights into brain metabolism. For the studies of dynamic concentration changes using fMRS, a high time evolution is of advantage for the characterization of the very small transient changes (around 0.2μmol/g). Therefore, measurements with the highest sensitivity are desirable. Recent studies at high field (7 Tesla) reported small metabolite concentration changes (around 0.2µmol/g) and in particular a lactate concentration increase varying between 10-23% during visual stimulation. Additionally, it is interesting to investigate metabolite changes during other stimulation. Therefore, the aim of this study was to investigate the metabolite changes during motor activation in the human brain and to compare these changes with those of visual activation

In vitro effects of 0 to 120 Grays of irradiation on bone viability and release of growth factors.

BACKGROUND High dose radiation therapy is commonly used in maxillofacial surgeries to treat a number of head and neck tumors. Despite its widespread use, little information is available regarding the effects of irradiation on bone cell viability and release of growth factors following dose-dependent irradiation. METHODS Bone samples were collected from porcine mandibular cortical bone and irradiated at doses of 0, 7.5, 15, 30, 60 and 120 Grays. Thereafter, cell viability was quantified, and the release of growth factors including TGFβ1, BMP2, VEGF, IL1β and RANKL were investigated over time. RESULTS It was observed that at only 7.5Gy of irradiation, over 85 % of cells were non-vital and by 60 Gy, all cells underwent apoptosis. Furthermore, over a 7-fold decrease in VEGF and a 2-fold decrease in TGFβ1 were observed following irradiation at all tested doses. Little change was observed for BMP2 and IL1β whereas RANKL was significantly increased for all irradiated samples. CONCLUSIONS These results demonstrate the pronounced effects of irradiation on bone-cell vitality and subsequent release of growth factors. Interestingly, the largest observed change in gene expression was the 7-fold decrease in VEGF protein following irradiation. Future research aimed at improving our understanding of bone following irradiation is necessary to further improve future clinical treatments

Crop-livestock interfaces established through adaptations of farmers' practices over the short and long term

Since the 1960s, there has been a global trend toward specializing and intensifying farming systems in order to produce more. However, several authors (Hendrickson et al., 2008; Griffon, 2009; Russelle et al., 2007; Wilkins, 2008) have denounced agricultural development based on these systems, citing such negative impacts as the excessive build-up of nutrients in soil and water, economic dependency on product prices and a decrease in biodiversity. Conversely, integrated crop-livestock farming systems (CLFS), which combine crop production with animal husbandry (Russelle et al., 2007, Hendrickson et al., 2008), are now being reconsidered as a means of improving farm and land sustainability (Herrero et al., 2010). CLFS systems improve nutrient cycles (via exchanges of manure and straw) and are a source of economies of scope (Vermersch, 2007). They have the potential to bring about diversification in cropping plans, crop rotations and crop and grassland locations (Bonny,2011). This double nature of diversity (of agricultural activities, of resources for production)can be seen from the adaptive capacity point of view (Milestad et al., 2012), i.e. as a source of the farming systems’ flexibility

Combining farmers' decision rules and landscape stochastic regularities for landscape modelling

International audienceLandscape spatial organization (LSO) strongly impacts many environmental issues. Modelling agricultural landscapes and describing meaningful landscape patterns are thus regarded as key-issues for designing sustainable landscapes. Agricultural landscapes are mostly designed by farmers. Their decisions dealing with crop choices and crop allocation to land can be generic and result in landscape regularities, which determine LSO. This paper comes within the emerging discipline called "landscape agronomy", aiming at studying the organization of farming practices at the landscape scale. We here aim at articulating the farm and the landscape scales for landscape modelling. To do so, we develop an original approach consisting in the combination of two methods used separately so far: the identification of explicit farmer decision rules through on-farm surveys methods and the identification of landscape stochastic regularities through data-mining. We applied this approach to the Niort plain landscape in France. Results show that generic farmer decision rules dealing with sunflower or maize area and location within landscapes are consistent with spatiotemporal regularities identified at the landscape scale. It results in a segmentation of the landscape, based on both its spatial and temporal organization and partly explained by generic farmer decision rules. This consistency between results points out that the two modelling methods aid one another for land-use modelling at landscape scale and for understanding the driving forces of its spatial organization. Despite some remaining challenges, our study in landscape agronomy accounts for both spatial and temporal dimensions of crop allocation: it allows the drawing of new spatial patterns coherent with land-use dynamics at the landscape scale, which improves the links to the scale of ecological processes and therefore contributes to landscape ecology.L'organisation du paysage influe sur les problèmes environnementaux. Modéliser les paysages pour les décrire à l'aide de formes significatives est une étage clé. Les paysages agricoles sont principalement construits par les agriculteurs dont les décision d'assolement peuvent être génériques et déterminer des régularités dans l'organisation du paysage. Cet article contribue à l'agronomie des paysage qui est une discipline émergente. Nous cherchons à articuler les échelles du paysage et de l'exploitation agricole en développant deux méthodes : l'une consiste à identifier les décisions des agriculteurs par le bais d'enquêtes, l'autre consiste à retrouver des régularités stochastiques dans le paysage par le bais de fouille de données. Nous avons appliqué cette approche au paysage de la plaine de Niort en France. Les résultats montrent que les décisions des agriculteurs en matière de tournesol et maïs sont génériques et ont des effets sur le paysages que des méthodes de fouille de données révèlent et quantifient