Cathodic voltage-controlled electrical stimulation of titanium implants as treatment for methicillin-resistant Staphylococcus aureus periprosthetic infections.

Effective treatment options are often limited for implant-associated orthopedic infections. In this study we evaluated the antimicrobial effects of applying cathodic voltage-controlled electrical stimulation (CVCES) of -1.8 V (vs. Ag/AgCl) to commercially pure titanium (cpTi) substrates with preformed biofilm-like structures of methicillin-resistant Staphylococcus aureus (MRSA). The in vitro studies showed that as compared to the open circuit potential (OCP) conditions, CVCES of -1.8 V for 1 h significantly reduced the colony-forming units (CFU) of MRSA enumerated from the cpTi by 97% (1.89 × 106 vs 6.45 × 104 CFU/ml) and from the surrounding solution by 92% (6.63 × 105 vs. 5.15 × 104 CFU/ml). The in vivo studies, utilizing a rodent periprosthetic infection model, showed that as compared to the OCP conditions, CVCES at -1.8 V for 1 h significantly reduced MRSA CFUs in the bone tissue by 87% (1.15 × 105 vs. 1.48 × 104 CFU/ml) and reduced CFU on the cpTi implant by 98% (5.48 × 104 vs 1.16 × 103 CFU/ml). The stimulation was not associated with histological changes in the host tissue surrounding the implant. As compared to the OCP conditions, the -1.8 V stimulation significantly increased the interfacial capacitance (18.93 vs. 98.25 µF/cm(2)) and decreased polarization resistance (868,250 vs. 108 Ω-cm(2)) of the cpTi. The antimicrobial effects are thought to be associated with these voltage-dependent electrochemical surface properties of the cpTi.

Chorea and rapidly progressive subcortical dementia in antiphospholipid syndrome.

Antiphospholipid antibodies are associated with a variety of neurologic manifestations, both in patients with and without concomitant systemic lupus erythematosus. We report a patient in whom chorea and rapidly progressive subcortical dementia developed in the setting of persistently high titers of antiphospholipid antibodies. While some manifestations of antiphospholipid syndrome can be clearly linked to vascular thrombosis, it is not known whether this is also true for patients affected with chorea, dementia, or both. In our patient, serial magnetic resonance imaging showed the progressive development of deep white matter lesions but no cortical infarcts. The development of widespread pulmonary arterial thrombosis and acute cerebral ischemia, evidenced clinically and on diffusion-weighted magnetic resonance imaging of the brain, provided indirect evidence for a thrombotic pathogenesis for this patient's neurologic disease. Anticoagulation should be considered as an adjunct to the treatment of patients with antiphospholipid antibodies and chorea or subcortical dementia.