Ferrocene-terminated alkanethiol self-assembled monolayers: An electrochemical and in situ surface-enhanced infra-red absorption spectroscopy study

The effect of anions on the redox behavior and structure of 11-ferrocenyl-1-undecanethiol (FcC11) monolayers (SAM) on Au(1 1 1) single crystal and Au(1 1 1-25 nm) thin film electrodes was investigated in 0.1 M solutions of HPF6, HClO4, HBF4, HNO3, and H2SO4 by cyclic voltammetry (CV) and in situ surface-enhanced infrared reflection-absorption spectroscopy (SEIRAS). We demonstrate that the FcC11 redox peaks shift toward positive potentials and broaden with increasing hydrophilicity of the anions. In situ surface-enhanced IR-spectroscopy (SEIRAS) provided direct access for the incorporation of anions into the oxidized adlayer. The coadsorption of anions is accompanied by the penetration of water molecules. The latter effect is particularly pronounced in aqueous HNO3 and H2SO4 electrolytes. The adlayer permeability increases with increasing hydrophilicity of the anions. We also found that even the neutral (reduced) FcC11 SAM is permeable for water molecules. Based on the property of interfacial water to reorient upon charge inversion, we propose a spectroscopic approach for estimating the potential of zero total charge of the FcC11-modified Au(1 1 1) electrodes in aqueous electrolytes.

The role of postoperative antibiotics in facial fractures: Comparing the efficacy of a 1-day versus a prolonged regimen

BACKGROUND The goal of this study was to evaluate the influence of the duration of postoperative antibiotics (1 day vs. ≥ 5 days) on wound infections following surgical treatment of facial fractures. METHODS Three hundred thirty-nine patient case histories with a total of 498 fractures were reviewed retrospectively with regard to infections occurring within a 6-month period following surgical management. Patients were divided into two groups based on the duration of postoperative antibiotics administered. Group A consisted of 125 patients who had 1 day of postoperative antibiotics, whereas Group B consisted of 214 patients who had five or more days of postoperative antibiotics. Statistical analysis was conducted to assess for possible differences in the rate of postoperative infections. RESULTS Five patients in Group A (4%) and seven patients in Group B (3.27%) developed infections within the follow-up period. Of these 12 patients, seven had sustained multiple facial bone fractures. Eleven infections occurred in patients with mandibular fractures and one in a midfacial fracture. Statistical analysis using Fisher's exact test showed no significant difference (p = 0.77) in the incidence of infection between Groups A and B. CONCLUSION In this retrospective study, the use of prolonged postoperative antibiotics in uncomplicated mandibular and midfacial fractures had no significant benefit in reducing the incidence of infections. LEVEL OF EVIDENCE Therapeutic study, level IV.

Cattle immunized against the pathogenic L-α-glycerol-3-phosphate oxidase of Mycoplasma mycoides subs. mycoides fail to generate neutralizing antibodies and succumb to disease on challenge

The membrane-associated enzyme L-α-glycerol-3-phosphate oxidase (GlpO) of Mycoplasma mycoides subs. mycoides (Mmm), the causal agent of contagious bovine pleuropneumonia (CBPP) has been identified as a virulence factor responsible for the release of toxic by-products such as H2O2 that mediate host cell injury. Since CBPP pathogenesis is based on host inflammatory reactions, we have determined the capacity of recombinant GlpO to generate in vivo protective responses against challenge in immunized cattle. We also investigated whether sera raised against recombinant GlpO in cattle and mice inhibit production of H2O2 by Mmm. Immunization of cattle with recombinant GlpO did not protect against challenge with a virulent strain of Mmm. Further, although both murine and bovine antisera raised against recombinant GlpO detected recombinant and native forms of GlpO in immunoblot assays with similar titres, only murine antibodies could neutralize GlpO enzymatic function. The data raise the possibility that Mmm has adapted to evade potential detrimental antibody responses in its definitive host.