Study on polyethylene glycol cross-linker in peptide-conjugated antibody on efficiency of cell capture and release

Cell separation is important in cell therapy and disease diagnosis. Therefore, various cell separation methods have been studied, but cellular damage and the need for pretreatment remain substantial problems. Recently, in the diagnostic field, the detachment and recovery of antibody-captured cells was actively studied to obtain more detailed information on cancer cells. Previously, we have developed a highly efficient cell separation method using microfibers. In the present study, the efficiency of cell capture and release was examined by controlling the molecular mobility of an immobilized antibody to efficiently detect cells with low expression of a marker molecule. We found that improvement in molecular mobility of antibodies enhances cell capture efficiency but decreases the detachment effectiveness of the captured cells. Therefore, the molecular mobility of antibodies can be utilized to control cell capture and release according to the level of expression of the marker molecule.

Experience With Prophylactic Gentamicin During Penile Prosthesis Surgery: A Retrospective Comparison of Two Different Doses

BACKGROUND

Gentamicin has been determined to be active against a wide range of bacterial infections and has been commonly used as a preoperative antibiotic for inflatable penile prosthesis (IPP) implantation. However, the best dosing regimen to produce the safest optimal prophylactic effect remains to be determined.

AIM

To compare low- and high-dose gentamicin as prophylaxis during IPP implantation.

METHODS

We retrospectively analyzed two groups of patients who underwent IPP placement from April 14, 2012 through April 13, 2016. Group 1 was composed of 490 patients who underwent IPP placement from April 14, 2012 through April 13, 2014 and received a low dose of preoperative gentamicin at 80 mg every 8 hours for 1 day. Group 2 was composed of 407 patients who underwent IPP placement from April 14, 2014 through April 13, 2016 and received a single high dose of preoperative gentamicin at 5 mg/kg. We compared the infection rates of IPP and any gentamicin-related toxicities. The same surgeon performed all procedures. All patients received additional vancomycin 1 g before incision and at 12 hours postoperatively.

OUTCOME

Demographic data and IPP infection rate were compared and potential toxicities from the higher dose of gentamicin were closely monitored.

RESULTS

There were no significant differences in mean age, mean body mass index, and mean interval for IPP placement and IPP infection between the two groups. No toxicity was seen with the higher gentamicin dose. Six cases in group 1 (five de novo cases and one redo case, infection rate = 1.22%) and three cases in group 2 (two de novo cases and one redo case, infection rate = 0.74%) were found to have IPP infection. The infection rate in group 2 appeared to be lower than that in group 1, although a significant statistical difference was not achieved (P = .057).

CLINICAL IMPLICATIONS

These findings would help guide urologists in choosing an optimal preoperative gentamicin dose for IPP surgery.

STRENGTHS AND LIMITATIONS

This is the first study to report on the usage of high-dose preoperative gentamicin for IPP surgery but with limitations as a retrospective study.

CONCLUSIONS

Although not achieving a statistical difference, there was a trend for patients receiving a higher dose of preoperative gentamicin to have a lower IPP infection rate. No toxicity was encountered from the 5-mg/kg gentamicin dose. We recommend following prophylactic high-dose gentamicin guidelines. Xie D, Gheiler V, Lopez I, et al. Experience With Prophylactic Gentamicin During Penile Prosthesis Surgery: A Retrospective Comparison of Two Different Doses. J Sex Med 2017;14:1160-1164.

Antibiotic patterns with inflatable penile prosthesis insertion

INTRODUCTION

A clear set of guidelines has not been defined in the use of antibiotics in penile prosthesis implantation. Aim.  We surveyed urologists throughout the United States to determine current practice patterns regarding antibiotic use in primary and revision penile prosthesis surgery.

METHODS

Fifty-two Sexual Medicine Society of North America (SMS) member urologist and 164 non-SMS member urologist responses were obtained.

MAIN OUTCOME MEASURES

The survey contained 10 questions regarding antibiotic selection for primary and revision inflatable penile prosthesis (IPP) implantation.

RESULTS

One hundred percent of responders in both groups utilize intraoperative antibiotics, most commonly vancomycin and gentamicin in both groups. Of SMS members, 94% prescribed postoperative home oral antibiotics in contrast to 88% of non-SMS members (P = 0.3). Among SMS members, the most common antibiotic prescribed postoperatively was levofloxacin 500 mg daily while among non-SMS members, the most common antibiotic postoperatively was cephalexin 500 mg 2-4 times daily. Of SMS members, antibiotic irrigation intraoperatively occurred with 100% and with 92% of non-SMS members (P = 0.04). Thirty-seven percent SMS physicians and 15% non-SMS physicians made modifications of intraoperative and postoperative antibiotics for high-risk patients (P = 0.001). In the circumstance of revision of a clinically noninfected IPP, 23% SMS and 16% non-SMS member physicians utilized additional antibiotics/treatment (P = 0.3). Sixteen of those surveyed admitted that they had been approached by their institution about their antibiotic use and asked to change. In the past 5 years, 29% surveyed have changed their practice patterns in antibiotic use.

CONCLUSIONS

There is significant difference between practice patterns of SMS and non-SMS urologists in terms of antibiotic irrigation usage, modifications for high-risk patients, and consensus about the importance of antibiotic use with Coloplast Titan implant (Coloplast, Minneapolis, MN, USA). A significant lack of uniformity exists among urologists performing prosthetic surgery with regard to antibiotic protocols. A standard set of guidelines may prove useful to implanters.

Antimicrobial peptides on calcium phosphate-coated titanium for the prevention of implant-associated infections

Prevention of implant-associated infections has been one of the main challenges in orthopaedic surgery. This challenge is further complicated by the concern over the development of antibiotic resistance as a result of using traditional antibiotics for infection prophylaxis. The objective of this study was to develop a technique that enables the loading and local delivery of a unique group of cationic antimicrobial peptides (AMP) through implant surfaces. A thin layer of micro-porous calcium phosphate (CaP) coating was processed by electrolytic deposition onto the surface of titanium as the drug carrier. The broad spectrum AMP Tet213 (KRWWKWWRRC) was selected and loaded onto the CaP coating. SEM, XRD and FTIR analyses confirmed the CaP coating to be micro-porous octacalcium phosphate. By using a luminescence spectrometer technique, it was demonstrated that a 7 μm thick porous CaP coating could load up to 9 μg of AMP/cm² using a simple soaking technique. The drug-loaded CaP coating (CaP-Tet213) was not cytotoxic for MG-63 osteoblast-like cells. The CaP-Tet213 implants had antimicrobial activity against both Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa) bacteria with 10⁶-fold reductions of both bacterial strains within 30 min as assessed by measuring colony-forming units (CFU). Repeated CFU assays on the same CaP-Tet213 specimen demonstrated retention of antimicrobial activity by the CaP-Tet213 surfaces through four test cycles. The susceptibility of bacteria to the CaP-Tet213 surfaces was also evaluated by assessing the inhibition of luminescence of P. aeruginosa containing a luxCDABE cassette at 4 h and 24 h with ∼92% and ∼77% inhibition of luminescence, respectively. It was demonstrated that CaP-Tet213 was a more efficient antimicrobial coating than CaP-MX226, CaP-hLF1-11 or CaP-tobramycin following incubation of CaP implants with equimolar concentrations of Tet213, the commercially developed antimicrobial peptide MX-226, hLF1-11 or tobramycin. A device coated with CaP-Tet213 could be a potential solution for the prevention of the peri-implant infection in orthopaedics.