Characterisation and evaluation of the regenerative capacity of Stro-4+ enriched bone marrow mesenchymal stromal cells using bovine extracellular matrix hydrogel and a novel biocompatible melt electro-written medical-grade polycaprolactone scaffold

Many skeletal tissue regenerative strategies centre around the multifunctional properties of bone marrow derived stromal cells (BMSC) or mesenchymal stem/stromal cells (MSC)/bone marrow derived skeletal stem cells (SSC). Specific identification of these particular stem cells has been inconclusive. However, enriching these heterogeneous bone marrow cell populations with characterised skeletal progenitor markers has been a contributing factor in successful skeletal bone regeneration and repair strategies. In the current studies we have isolated, characterised and enriched ovine bone marrow mesenchymal stromal cells (oBMSCs) using a specific antibody, Stro-4, examined their multipotential differentiation capacity and, in translational studies combined Stro-4+ oBMSCs with a bovine extracellular matrix (bECM) hydrogel and a biocompatible melt electro-written medical-grade polycaprolactone scaffold, and tested their bone regenerative capacity in a small in vivo, highly vascularised, chick chorioallantoic membrane (CAM) model and a preclinical, critical-sized ovine segmental tibial defect model.Proliferation rates and CFU-F formation were similar between unselected and Stro-4+ oBMSCs. Col1A1, Col2A1, mSOX-9, PPARG gene expression were upregulated in respective osteogenic, chondrogenic and adipogenic culture conditions compared to basal conditions with no significant difference between Stro-4+ and unselected oBMSCs. In contrast, proteoglycan expression, alkaline phosphatase activity and adipogenesis were significantly upregulated in the Stro-4+ cells. Furthermore, with extended cultures, the oBMSCs had a predisposition to maintain a strong chondrogenic phenotype. In the CAM model Stro-4+ oBMSCs/bECM hydrogel was able to induce bone formation at a femur fracture site compared to bECM hydrogel and control blank defect alone. Translational studies in a critical-sized ovine tibial defect showed autograft samples contained significantly more bone, (4250.63 mm3, SD = 1485.57) than blank (1045.29 mm3, SD = 219.68) ECM-hydrogel (1152.58 mm3, SD = 191.95) and Stro-4+/ECM-hydrogel (1127.95 mm3, SD = 166.44) groups.Stro-4+ oBMSCs demonstrated a potential to aid bone repair in vitro and in a small in vivo bone defect model using select scaffolds. However, critically, translation to a large related preclinical model demonstrated the complexities of bringing small scale reported stem-cell material therapies to a clinically relevant model and thus facilitate progression to the clinic

Farmers\u2019 exposure to herbicides in North Italy: assessment under real-life conditions in small-size rice and corn farms

Although rice and corn are two main cash crops in Lombardy (North Italy) and their cultivation involves several thousands of farmers, risk assessment of pesticide exposure is rarely done, especially in small and medium sized enterprises. With the use of pads for environmental monitoring (OECD protocol), of pre- and post-exposure 24-hour urine collection for biological monitoring and of hand wash for hands\u2019 exposure, we measured the exposure of 28 agricultural workers to propanil and terbuthylazine in real-life working conditions. In propanil applicators, median daily exposure on the clothes was 73.5 mcmol per worker, while the exposure on the skin was 22.4 mcmol. For terbuthylazine, these exposures were 37.2 mcmol and 0.86 mcmol per worker, respectively. Median excretion of the propanil metabolite (3,4-dichloroaniline) after exposure was 84 nmol in 24-hour urine, and 13 nmol for the metabolite of terbuthylazine. Risk assessment performed by comparing to the AOELs of the applied active ingredients with an estimated internal dose, obtained based on the measured levels of skin and hand exposure and the percentage of dermal absorption of the active ingredients considered showed that 4 propanil workers, and no terbuthylazine workers, were overexposed. Our study helps define and confirm relationships between different exposure determinants, which can be used in the development of tools for risk assessment of exposure to pesticides in small and medium sized enterprises

Validation and performance assessment of a preclinical SiPM-based SPECT/MRI insert

A preclinical insert for small animal simultaneous SPECT and MR imaging, in particular for imaging mouse brains, is presented. It consists of ten static magnetic resonance imaging (MRI)-compatible gamma cameras based on tiles of silicon photomultipliers readout by a multichannel ASIC and coupled to 5 cm × 5 cm CsI(Tl) scintillators and to an MRI-compatible multipinhole collimator. Calibration and image reconstruction algorithm are illustrated. Mutual compatibility is demonstrated along with imaging performance that is comparable with other non-MR micro-SPECT systems: 0.9 mm tomographic spatial resolution across a transverse field of view of 15.6 mm, 12% energy resolution (at 140 keV), and 1105 cps/MBq sensitivity. Experimental results with phantoms (glass capillaries of 290 μm diameter and a mini Derenzo) are presented