This continuing series gathers and presents original research results on the leading edge of medicine and biology. Each article has been carefully selected in an attempt to present substantial topical data across a broad spectrum. Topics discussed in this compilation include a review on the optimisation of the formulations of metronidazole through a different administration route; the use of metronidazole in cancer gene therapy and targeted cell ablation; protective roles of glutathione peroxidases in diabetes; stem cell disorders and bone marrow transplantation; catalase gene mutant mice; what animal models of inflammatory arthritis teach us about bone damage; methylprednisolone use in autoimmune diseases; the clinical use of methylprednisolone in oncology; how pretreatment with methylprednisolone reduces adverse clinical effects of inflammatory response induced by heart surgery and cardiopulmonary bypass; and the potential side effects of methylprednisolone.