Effects of methylprednisolone on femoral bone marrow: age-dependent susceptibility.

PURPOSE: We aimed to test our primary hypothesis that the effects of methylprednisolone on bone marrow in chickens are age-sensitive and increase with prolonged treatment and our secondary hypothesis that the effects of methylprednisolone on bone marrow can have individual effects. METHODS: Sixteen control (group A) and 29 methylprednisolone-treated (group B) chickens were categorised by age: pubertal chicks (subgroups A1, B1), young hens (A2, B2), and adult hens (A3, B3). Histologic evaluation 12 to 50 weeks after the start of methylprednisolone treatment included fat cell proliferation, trabecular bone loss, necrosis of bone and marrow, and new bone formation in the femoral head, neck, and intertrochanteric area. RESULTS: There were significant differences between groups A1 and B1 in new bone formation in the femoral neck (P = 0.048) and fat cell proliferation in the femoral head (P = 0.008) and neck (P = 0.048). New bone formation in the femoral head was also significantly different (P = 0.023) between groups A2 and B2. No differences were noted between groups A3 and B3 (all P>0.05). Necrosis of bone and marrow was observed in four control and three methylprednisolone-treated chickens (P>0.05). Significant new bone formation and fat cell proliferation in pubertal and young chickens occurred 12 to 19 weeks after administration of high-dose methylprednisolone. CONCLUSIONS: Younger animals may be more susceptible to methylprednisolone, and responses to methylprednisolone in femoral marrow may vary among individuals.

The use of nanoscale visible light-responsive photocatalyst TiO2-Pt for the elimination of soil-borne pathogens.

Exposure to the soil-borne pathogens Burkholderia pseudomallei and Burkholderia cenocepacia can lead to severe infections and even mortality. These pathogens exhibit a high resistance to antibiotic treatments. In addition, no licensed vaccine is currently available. A nanoscale platinum-containing titania photocatalyst (TiO(2)-Pt) has been shown to have a superior visible light-responsive photocatalytic ability to degrade chemical contaminants like nitrogen oxides. The antibacterial activity of the catalyst and its potential use in soil pathogen control were evaluated. Using the plating method, we found that TiO(2)-Pt exerts superior antibacterial performance against Escherichia coli compared to other commercially available and laboratory prepared ultraviolet/visible light-responsive titania photocatalysts. TiO(2)-Pt-mediated photocatalysis also affectively eliminates the soil-borne bacteria B. pseudomallei and B. cenocepacia. An air pouch infection mouse model further revealed that TiO(2)-Pt-mediated photocatalysis could reduce the pathogenicity of both strains of bacteria. Unexpectedly, water containing up to 10% w/v dissolved soil particles did not reduce the antibacterial potency of TiO(2)-Pt, suggesting that the TiO(2)-Pt photocatalyst is suitable for use in soil-contaminated environments. The TiO(2)-Pt photocatalyst exerted superior antibacterial activity against a broad spectrum of human pathogens, including B. pseudomallei and B. cenocepacia. Soil particles (<10% w/v) did not significantly reduce the antibacterial activity of TiO(2)-Pt in water. These findings suggest that the TiO(2)-Pt photocatalyst may have potential applications in the development of bactericides for soil-borne pathogens.