The efficacy of silver-embedded polypropylene-grafted polyethylene glycol-coated ventricular catheters on prevention of shunt catheter infection in rats.

PURPOSE: Catheter-related infection is a major complication of ventriculoperitoneal shunt in children. The aim of this study is to determine inflammatory response and the efficacy of polypropylene-grafted polyethylene glycol (PP-g-PEG) copolymer and silver nanoparticle-embedded PP-g-PEG (Ag-PP-g-PEG) polymer-coated ventricular catheters on the prevention of catheter-related infections on a new experimental model of ventriculoperitoneal shunt in rats. METHODS: Thirty six Wistar albino rats were divided into six groups: group 1, unprocessed sterile silicone catheter-embedded group; group 2, sterile PP-g-PEG-coated catheter group; group 3, sterile Ag-PP-g-PEG-coated catheter group; group 4, infected unprocessed catheter group; group 5, infected PP-g-PEG-coated catheter group; and group 6, infected Ag-PP-g-PEG-coated catheter group, respectively. In all groups, 1-cm piece of designated catheters were placed into the cisterna magna. In groups 4, 5, and 6, all rats were infected with 0.2 mL of 10 × 10(6) colony forming units (CFU)/mL Staphylococcus epidermidis colonies before the catheters were placed. Thirty days after implantation, bacterial colonization in cerebrospinal fluid and on catheter pieces with inflammatory reaction in the brain parenchyma was analyzed quantitatively. RESULTS: Sterile and infected Ag-PP-g-PEG-covered groups revealed significantly lower bacteria colony count on the catheter surface (ANOVA, 0 ± 0, p < 0.001; 1.08 ± 0.18, p < 0.05, respectively). There was moderate inflammatory response in the parenchyma in group 4, but in groups 5 and 6, it was similar to that of the sterile group (ANOVA, 16.33 ± 3.02, p < 0.001; 4.00 ± 0.68, p < 0.001, respectively). CONCLUSIONS: The PP-g-PEG, especially Ag-PP-g-PEG polymer-coated ventricular catheters are more effective in preventing the catheter-related infection and created the least inflammatory reaction in the periventricular parenchyma.

Soft tissue response to the presence of polypropylene-G-poly(ethylene glycol) comb-type graft copolymers containing gold nanoparticles.

The aim of this study is to evaluate the soft tissue response of the pure and Au-embedded PPg-PEG. PP-g-PEG2000, PP-g-PEG4000, Au-PP-g-PEG2000, and AuPP-g-PEG4000 were obtained via chlorination of polypropylene and polyethylene glycol in the presence of a base with a "grafting onto" technique. Solvent cast films of these four copolymers with PP as a control group were embedded into five different rats. After 30 days of implantation, microscopic evaluation of inflammation and SEM analysis were done. PP had the most intense inflammatory reaction among the other polymers. PP-PEG block copolymers with high molecular weight and gold-nanoparticles-embedded ones revealed mild inflammatory reaction independently. SEM assessment revealed punched hole-like defects on the surface of all polymer samples except for PP. Graft copolymers with PEG, especially Au-attached ones, have favorable soft tissue response, and inflammatory reaction becomes milder as the number of PEG side chains increases.

Antimicrobial Effect of Polymer-Based Silver Nanoparticle Coated Pedicle Screws: Experimental Research on Biofilm Inhibition in Rabbits.

STUDY DESIGN: Antimicrobial effect of a novel silver-impregnated pedicle screw in rabbits. OBJECTIVE: A novel spine implant model was designed to study the antimicrobial effect of a modified Titanium (Ti) pedicle screws with methicillin-resistant Staphylococcus aureus (MRSA) in multiple surgical sites in the lumbar spine of a rabbit. SUMMARY OF BACKGROUND DATA: Infection in spinal implant is of great concern. Anti-infection strategies must be tested in relevant animal models that will lead to appropriate clinical studies. METHODS: Fourteen New Zealand white rabbits were divided into 2 groups: group 1: infected unmodified Ti screw group (n =  6), and group 2: infected polyethylene glycol grafted, polypropylene-based silver nanoparticle (PP-g-PEG-Ag) covered Ti screw group (n = 6), and 2 rabbits as sterile (sham-operated and control) group. In all groups, left L4-right L6 vertebra levels were exposed and screws were drilled to transverse processes after contamination of burr holes and surrounding tissue with 0.1 mL of 10 colony forming units (CFU) MRSA solutions in groups 1 and 2. After 21 days, samples were collected and infection was analyzed via light and scanning electron microscopy and culturing. Silver nanoparticles (Ag-NP) on the screws and tissues were assayed pre and postoperatively. RESULTS: The bacterial colony count for modified-Ti screw group was lower than for unmodified Ti screw (17.2 versus 200 x 10(3) CFU/mL, P = 0.029) with less biofilm formation. There was no difference in duration of surgery among groups and within the surgical sites. Ag-NPs were detected on the screw surface postoperatively. CONCLUSION: This novel experimental design of implantation in rabbits is easy to apply and resembles human stabilization technique. Modified Ti screws were shown to have antimicrobial effect especially inhibiting the biofilm formation. This anchored Ag NPs that remained after 21st day of implantation shows that it is resistant to tapping forces of the screw.

Subdural empyema and unilateral pansinusitis due to a tooth infection.

Paranasal sinus infections are very common. Dental infections, tumours and anatomical malformations can cause unilateral sinusitis. Most cases can be treated without complications. However, rare life-threatening intracranial complications can occur. Generally, an intracranial complication progresses rapidly and can cause meningismus, focal neurological disorders, loss of consciousness and seizures. In such cases, an emergency craniotomy and concurrent sinus surgery are required. This article presents a 16-year-old patient with pansinusitis and subdural empyema that developed after a dental abscess.

Comparison of the Toxicities of Ethylene Vinyl Alcohol Copolymer (EVOH) Preparations, Dimethyl Sulphoxide and N-Butyl 2-Cyanoacrylate on Cerebral Parenchyma in an Experimental Rabbit Model.

AIM: Ethylene vinyl alcohol copolymer (EVOH), its organic solvent dimethyl sulfoxide (DMSO), and N-Butyl 2-Cyanoacrylate (NBCA) are widely used in neurovascular embolization procedures and yet with potential risk of cytotoxicity. The aim of this study was to evaluate the toxic effect of EVOH-DMSO, its solvent DMSO and NBCA on cerebral parenchyma in a rabbit model. MATERIAL AND METHODS: Forty-eight albino male rabbits were divided into 6 groups based on the substance injected into the parenchyma; normal saline, DMSO, NBCA, 6% EVOH-DMSO and 20% EVOH-DMSO and control group. At 72 hours the subjects were sacrificed and brain samples were harvested for histopathological examination and lipid peroxidase measurements. RESULTS: Neuronal degeneration and inflammatory reaction in the brain parenchyma was prominent especially in DMSO group and EVOHDMSO groups. Furthermore, the extent of degeneration and inflammatory reaction was related to the concentration of the embolic agent in the EVOH group. Lipid peroxidase activity was significantly increased in the NBCA group as compared to all but to 20 % EVOH-DMSO group. CONCLUSION: EVOH and its solvent DMSO cause degeneration and inflammatory reaction in brain parenchyma and for EVOH this reaction was appeared to be dose dependent.

Synthesis of microbial elastomers based on soybean oily acids. Biocompatibility studies.

Biocompatibility studies of the autoxidized and unoxidized unsaturated medium-long chain length (m-lcl) co-poly-3-hydroxyalkanoates (m-lclPHAs) derived from soya oily acids have been reported. Pseudomonas oleovorans was grown on a series of mixtures of octanoic acid (OA) and soya oily acids (Sy) with weight ratios of 20:80, 28:72 and 50:50 in order to obtain unsaturated m-lcl copolyesters coded PHO-Sy-2080, PHO-Sy-2872 and PHO-Sy-5050, respectively. The PHA films were obtained by solvent cast from CHCl(3). They were all originally sticky and waxy except PHO-Sy-5050. Autoxidation of the unsaturated copolyester films was carried out on exposure to air at room temperature in order to obtain crosslinked polymers. They became a highly flexible elastomer after being autoxidized (about 40 days of autoxidation). The in vivo tissue reactions of the autoxidized PHAs were evaluated by subcutaneous implantation in rats. The rats appeared to be healthy throughout the implantation period. No symptom such as necrosis, abscess or tumorigenesis was observed in the vicinity of the implants. Retrieved materials varied in their physical appearance after 6 weeks of implantation. In vivo biocompatibility studies of the medical applications indicated that the microbial copolyesters obtained were all biocompatible and especially the PHOSy series of copolyesters had the highest biocompatibility among them.