Change in the molecular properties of CH1641 prions after transmission to wild-type mice: Evidence for a single strain.

AIM: CH1641 was discovered in 1970 as a scrapie isolate that was unlike all other classical strains of scrapie isolated so far. We performed bio-assays of CH1641 in mice in order to further characterise this specific isolate. METHODS: We inoculated the original CH1641 isolate into ovine and bovine prion protein (PrP) transgenic mice as well as wild-type mice. In addition, we performed cross- and back passages between the various mouse lines to examine if one identical prion strain was isolated in all mouse lines or whether multiple prion strains exist in CH1641. RESULTS: We report the first successful transmission of CH1641 to wild-type RIII mice and via RIII mice to wild-type VM mice. Unexpectedly, analysis of the protease-resistant prion protein (PrPres ) in wild-type mice showed a classical scrapie banding pattern differing from the banding pattern of the original CH1641 isolate. Cross- and back passages of CH1641 between the various mouse lines confirmed that the same prion strain had been isolated in all mouse lines. CONCLUSIONS: The CH1641 isolate consists of a single prion strain but its molecular banding pattern of PrPres differs between wild-type mice and PrP transgenic mice. Consequently, molecular banding patterns of PrPres should be used with caution in strain typing since they do not solely depend on the properties of the prion strain but also on the host prion protein.

Effects of plasma rich in growth factors on wound healing in patients with venous ulcers.

Introduction: Significant evidence suggests that plasma-rich in growth factors (PRGF) favor the repair of chronic wounds, enabling a rapid return to functionality. However, components of PRGF and their effects on persistent ulcers and epithelial tissues are not well characterized. The goals of this research were to analyze the biological properties of platelet-derived factors, to examine their effectiveness on healing of venous ulcers, and to establish a correlation with clinical and sociodemographic data. Methods: For the preparation of PRGF, the centrifugation technique was used, obtaining a 100 % autologous and biocompatible blood sample that was treated with sodium citrate and calcium chloride. The patients were attended weekly at the outpatient clinic for nursing consultation and wound dressing changes, with PRGF application every 15 days. The treatment protocols are described, and follow-up results are reported. Results: Initially, the patients' ulcers ranged in sizes from 4 to 84 cm2. After 12 weeks of treatment, there was a significant mean reduction of 46.2 % in ulcer area. At baseline, epithelial tissue was absent in all venous ulcers, but its presence grew significantly by the treatment period. However, the reduction of the area of the ulcers did not show significant correlation with the concentrations of the patient's growth factors. Conclusions: Using the established protocol for PRGF isolating, it was possible to obtain a product with the presence of the six growth factors related to tissue regeneration and observed a positive response on wound healing following treatment of venous ulcers, with capacity to accelerate re-epithelialization and restore the skin functional integrity.