No abstract

Hemolytic uremic syndrome (HUS) secondary to Streptococcus pneumoniae infections (pHUS) has been well reported in the literature and accounts for roughly 5% of all the cases of HUS. However, this condition is likely under-diagnosed and the incidence is believed to be increasing. Given this increase in incidence of pHUS, it is important to have an understanding of the optimal means to manage the disease. We report a case of a 2-year-old male with pneumonia, acute kidney injury (AKI), microangiopathic hemolytic anemia (MAHA), and thrombocytopenia, diagnosed with pHUS and successfully treated with antibiotics, washed red blood cell (RBC) transfusions, plasma exchange (PE) with 5% albumin replacement, steroids, and hemodialysis. The response seen in our patient adds to the current literature and further supports the use of PE with albumin in patients with pHUS.

Although osteosarcoma is the most common primary malignant bone tumor in children and adolescents, its cell of origin and the genetic alterations are unclear. Previous studies have shown that serially introducing hTERT, SV40 large TAg, and H-Ras transforms human mesenchymal stem cells into two distinct sarcomas cell populations, but they do not form osteoid. In this study, β-catenin was introduced into mesenchymal stem cells already containing hTERT and SV40 large TAg to analyze if this resulted in a model which more closely recapitulated osteosarcoma. Results. Regardless of the level of induced β-catenin expression in the stable transfectants, there were no marked differences induced in their phenotype or invasion and migration capacity. Perhaps more importantly, none of them formed tumors when injected into immunocompromised mice. Moreover, the resulting transformed cells could be induced to osteogenic and chondrogenic differentiation but not to adipogenic differentiation. Conclusions. β-catenin, although fostering osteogenic differentiation, does not induce the malignant features and tumorigenicity conveyed by oncogenic H-RAS when introduced into partly transformed mesenchymal stem cells. This may have implications for the role of β-catenin in osteosarcoma pathogenesis. It also may suggest that adipogenesis is an earlier branch point than osteogenesis and chondrogenesis in normal mesenchymal differentiation.