Plasmon-Based Biofilm Inhibition on Surgical Implants.

The insertion of an implant in the body of a patient raises the risk of a posterior infection and formation of a biofilm, which can have critical consequences on the patient's health and be associated with a high sanitary cost. While antibacterial agents can be used to prevent the infection, such a strategy is time-limited and causes bacteria resistance. As an alternative to biochemical approaches, we propose here to use light-induced local hyperthermia with plasmonic nanoparticles. This strategy is implemented on surgical meshes, extensively used in the context of hernia repairing, one of the most common general surgeries. Surgical meshes were homogeneously coated with gold nanorods designed to efficiently convert near-infrared light into heat. The modified mesh was exposed to a biofilm of Staphylococcus aureus ( S. aureus) bacteria before being treated with a train of light pulses. We systematically study how the illumination parameters, namely fluence, peak intensity and pulse length, influence the elimination of attached bacteria. Additionally, fluorescence confocal microscopy provides us some insight on the mechanism involved in the degradation of the biofilm. This proof-of-principle study opens a new set of opportunities for the development of novel disinfection approaches combining light and nanotechnology.

The mechanism of adhesion and graft polymerization of a PNIPAAm thermoresponsive hydrogel to polypropylene meshes.

In this study, a commercial and fully flexible monofilament mesh has been used for the deposition of a thermosensitive hydrogel, generated by graft copolymerization of N-isopropylacrylamide (NIPAAm) and N,N'-methylene bis(acrylamide) (MBA) monomers. The mechanism of adhesion and graft copolymerization have been elucidated combining micro- and standard spectroscopy techniques such as Raman spectroscopy, FTIR spectroscopy and XPS, before and after the activation of the polypropylene (PP) fibre surface by using oxygen-plasma. The good covalent interactions among NIPAAm monomers and PP fibres, and the hydrogel chain growth in such flexible bidimensional structures, were demonstrated. Additionally, the thermoresponsive properties of PNIPAAm were obtained (VPTT behaviour). The bilayer system is stable below and above a low critical solution temperature (LCST) of 33.2 °C.

Evaluation of Community Programs for Early Childhood Development: Parental Perspectives and Recommendations.

Objectives Optimal early childhood development is crucial for promoting positive child health outcomes. Community programs supporting child development are available throughout the United States but general parental perceptions of such programs are not well understood. This study aimed to examine parental perceptions of community programs for early childhood development in a semi-urban city of the US. Methods Data were collected from focus groups (n = 4) composed of English-fluent parents from the local community with at least one child aged 0-5 years. After generation of verbatim transcripts, data were analyzed by two independent coders in order to identify themes. Results Parental perceptions were categorized into four areas: (1) Utilization of community services, (2) Helpful aspects of community services, (3) Negative aspects of community services and (4) Parental recommendations for improved resource utilization. Helpful aspects identified included social and economic support, provision of parental education, and developmental screening and medical support. Negative aspects included utilization of standardized assessment tools, awareness of agencies and resources, and access to services. In order to improve resource utilization, parents suggested improved communication with parents and the child's medical home, transparency, and translation of program information into other languages. Conclusions For Practice Overall, participants felt that community programs that support early childhood development and parenting were helpful. However, community agencies can improve on communication with parents and medical providers as well as translation of program information.

Parents' adverse childhood experiences and mental health screening using home visiting programs: A pilot study.

BACKGROUND: Adverse childhood experiences (ACEs) are associated with adult high-risk behaviors and diseases. There is value in screening parents for ACEs given the repercussions parental ACEs may have on parenting behaviors and child development. The primary aim of this study was to assess the feasibility of parental ACE screening in the home setting. A secondary aim was to evaluate whether or not maternal ACEs correlated with maternal mental health measures. METHODS: Two home visiting programs that support early childhood development and conduct parental mental health screening implemented ACE screening for parents of infants <1 year of age. Descriptive statistics were produced for population surveillance of ACEs as well as standard practice screens for depression, anxiety, substance use, and intimate partner violence. Logistic models were used to examine associations between ACE score and mental health measures. RESULTS: A total of 110 parents completed the ACE screen. All possible ACE score outcomes were represented (0-10). A trend toward association of positive prenatal maternal depression screen with ACE score was identified (p = .05). CONCLUSION: This novel prospective home-based screening program for parental ACEs was feasible and identified a trend toward increasing ACE score association with positive prenatal maternal depression screen.

Mechanical Properties of Smart Polypropylene Meshes: Effects of Mesh Architecture, Plasma Treatment, Thermosensitive Coating, and Sterilization Process.

Smart polypropylene (PP) hernia meshes were proposed to detect surgical infections and to regulate cell attachment-modulated properties. For this purpose, lightweight and midweight meshes were modified by applying a plasma treatment for subsequent grafting of a thermosensitive hydrogel, poly(N-isopropylacrylamide) (PNIPAAm). However, both the physical treatment with plasma and the chemical processes required for the covalent incorporation of PNIPAAm can modify the mechanical properties of the mesh and thus have an influence in hernia repair procedures. In this work, the mechanical performance of plasma-treated and hydrogel-grafted meshes preheated at 37 °C has been compared with standard meshes using bursting and the suture pull out tests. Furthermore, the influence of the mesh architecture, the amount of grafted hydrogel, and the sterilization process on such properties have been examined. Results reveal that although the plasma treatment reduces the bursting and suture pull out forces, the thermosensitive hydrogel improves the mechanical resistance of the meshes. Moreover, the mechanical performance of the meshes coated with the PNIPAAm hydrogel is not influenced by ethylene oxide gas sterilization. Micrographs of the broken meshes evidence the role of the hydrogel as reinforcing coating for the PP filaments. Overall, results confirm that the modification of PP medical textiles with a biocompatible thermosensitive hydrogel do not affect, and even improve, the mechanical requirements necessary for the implantation of these prostheses in vivo.

In vivo soft tissue reinforcement with bacterial nanocellulose.

The use of surgical meshes to reinforce damaged internal soft tissues has been instrumental for successful hernia surgery; a highly prevalent condition affecting yearly more than 20 million patients worldwide. Intraperitoneal adhesions between meshes and viscera are one of the most threatening complications, often implying reoperation or side effects such as chronic pain and bowel perforation. Despite recent advances in the optimization of mesh porous structure, incorporation of anti-adherent coatings or new approaches in the mesh fixation systems, clinicians and manufacturers are still pursuing an optimal material to improve the clinical outcomes at a cost-effective ratio. Here, bacterial nanocellulose (BNC), a bio-based polymer, is evaluated as a soft tissue reinforcement material regarding mechanical properties and in vivo anti-adhesive performance. A double-layer BNC laminate proved sufficient to meet the standards of mechanical resistance for abdominal hernia reinforcement meshes. BNC-polypropylene (BNC-PP) composites incorporating a commercial mesh have also been prepared. The in vivo study of implanted BNC patches in a rabbit model demonstrated excellent anti-adherent characteristics of this natural nanofibrous polymer 21-days after implantation and the animals were asymptomatic after the surgery. BNC emerges as a novel and versatile hernioplasty biomaterial with outstanding mechanical and anti-adherent characteristics.

A prospective, randomised, controlled, double-blind phase I-II clinical trial on the safety of A-Part Gel as adhesion prophylaxis after major abdominal surgery versus non-treated group.

BACKGROUND: Postoperative adhesions occur when fibrous strands of internal scar tissue bind anatomical structures to one another. The most common cause of intra-abdominal adhesions is previous intra-abdominal surgical intervention. Up to 74% of intestinal obstructions are caused by post surgical adhesions. Although a variety of methods and agents have been investigated to prevent post surgical adhesions, the problem of peritoneal adhesions remains largely unsolved. Materials serving as an adhesion barrier are much needed. METHODS/DESIGN: This is a prospective, randomised, controlled, patient blinded and observer blinded, single centre phase I-II trial, which evaluates the safety of A-Part Gel as an adhesion prophylaxis after major abdominal wall surgery, in comparison to an untreated control group. 60 patients undergoing an elective median laparotomy without prior abdominal surgery are randomly allocated into two groups of a 1:1- ratio. Safety parameter and primary endpoint of the study is the occurrence of wound healing impairment or peritonitis within 28 (+10) days after surgery. The frequency of anastomotic leakage within 28 days after operation, occurrence of adverse and serious adverse events during hospital stay up to 3 months and the rate of adhesions along the scar within 3 months are defined as secondary endpoints. After hospital discharge the investigator will examine the enrolled patients at 28 (+10) days and 3 months (+/-14 days) after surgery. DISCUSSION: This trial aims to assess, whether the intra-peritoneal application of A-Part Gel is safe and efficacious in the prevention of post-surgical adhesions after median laparotomy, in comparison to untreated controls.

Polypropylene mesh for hernia repair with controllable cell adhesion/de-adhesion properties.

Herein, a versatile bilayer system, composed by a polypropylene (PP) mesh and a covalently bonded poly(N-isopropylacrylamide) (PNIPAAm) hydrogel, is reported. The cell adhesion mechanism was successfully modulated by controlling the architecture of the hydrogel in terms of duration of PNIPAAm grafting time, crosslinker content, and temperature of material exposure in PBS solutions (below and above the LCST of PNIPAAm). The best in vitro results with fibroblast (COS-1) and epithelial (MCF-7) cells was obtained with a mesh modified with a porous iPP-g-PNIPAAm bilayer system, prepared via PNIPAAm grafting for 2 h at the lowest N,N'-methylene bis(acrylamide) (MBA) concentration (1 mM). Under these conditions, the detachment of the fibroblast-like cells was 50% lower than that of the control, after 7 days of cell incubation, which represents a high de-adhesion of cells in a short period. Moreover, the whole system showed excellent stability in dry or wet media, proving that the thermosensitive hydrogel was well adhered to the polymer surface, after PP fibre activation by cold plasma. This study provides new insights on the development of anti-adherent meshes for abdominal hernia repair.

Polyvinyl alcohol gel prevents adhesion re-formation after adhesiolysis in a rabbit model.

BACKGROUND: Chronic pain, infertility, and bowel obstructions are possible consequences of abdominal adhesions, which can highly affect the patient's quality of life. Patients in whom adhesiolysis has been performed are at high risk for recurrence of adhesions. For that reason, the present study focused on the re-formation of adhesions after adhesiolysis and on the possibility of avoiding it by using the adhesion barrier polyvinyl alcohol (PVA)-gel. MATERIALS AND METHODS: A randomized controlled study was conducted to prove the effectiveness of PVA-gel in reducing postoperative adhesion re-formation after relaparotomy. Moreover, ultrasound was evaluated as a noninvasive technique to determine abdominal adhesion in a rabbit model. All animals underwent an initial laparotomy to cause adhesions and subsequent adhesiolysis in the relaparotomy. PVA-gel was placed onto a side wall defect in 12 animals. Another 12 rabbits served as a control group without PVA-gel being used. Ultrasound before final laparotomy was performed to predict the prevalence of adhesions. Macroscopic evaluation of adhesion formation and planimetry were used to determine the amount of adhesion. RESULTS: PVA-gel was found to reduce significantly the amount of adhesion formation after relaparotomy (P = 0.0001) in comparison with the control group. Here severe adhesion formation was found to develop. The positive-predictive value (100%) for adhesion evaluation using ultrasound is highly satisfying in the rabbit model. CONCLUSIONS: Adhesion re-formation after relaparotomy was found to decrease significantly through the use of PVA-gel. Ultrasound as a noninvasive technique of adhesion detection is a sufficient and reliable method for detecting adhesion formations.

A-part gel-an efficient adhesion prevention barrier.

Two different poly(vinyl alcohol)-based gels (A-Part Gel) were compared and evaluated as possible adhesion prophylaxis gels. The gels were implanted to act as a physical barrier-and thus to prevent adhesions-in a rabbit sidewall model. The absorption time of any adhesion barrier is a critical parameter, since the wounded tissue needs to be covered during the healing process. Crosslinking by freeze-thawing helped to prolong the absorption time of the gels. To better understand the in vivo absorption, the gels were investigated in various physical in vitro methods such as decay measurements and experiments performed in a Soxhlet extraction thimble. The in vivo applicability of the gels by surgeons was judged in squeezing force measurements. The ability to cover the wounded area securely was measured with simple spreading experiments. Both gels could be squeezed out of the syringes easily and showed a homogenous spreading behavior. Comparing the two gels, the results of the in vitro absorption experiments were contradictive. Further, in vivo tests with correlations to the proposed in vitro measurements will reveal the correct interpretation. Nevertheless, the results in a pilot rabbit sidewall model were excellent for both A-Part gels, but only one gel was chosen for extended studies, showing only 20% adhesions when compared with the control group showing 100% strong adhesion formations. These data will be evaluated in other studies, and the use of an A-Part PVA-CMC gel for adhesion prevention has to be supported in clinical studies.

Tracking the urinary excretion of high molar mass poly(vinyl alcohol).

The fate of poly(vinyl alcohol) (PVA) of weight average molar mass of 125,000 g/mol after administration into the peritoneum of rabbits has bean studied by various methods. PVA was spin-labeled with a nitroxide radical and then detected in urine using electron spin resonance (ESR) spectroscopy. Furthermore, unlabeled polymer was also administered to rabbits, then the urine was collected, dialyzed, precipitated, and the excretion of PVA was confirmed by size exclusion chromatography (SEC), FTIR spectroscopy, and (1)H NMR spectroscopy. ESR and SEC results show that, despite its relatively high molar mass, PVA is excreted through the kidneys without significant molar mass changes. Nevertheless, NMR and FTIR spectra show slight differences between the excreted and neat PVA. Possible causes of these discrepancies are discussed.

Fixation of Light Weight Polypropylene Mesh with n-Butyl-2-cyanocrylate in Pelvic Floor Surgery: Experimental Design Approach in Sheep for Effectiveness Evaluation.

OBJECTIVE: The aim of this study was to find a proper experimental design and to evaluate n-butyl-2-cyanoacrylate (Histoacryl) as a fixation method for a light-weight and large pore PP mesh (Synthetic PP Mesh-1) using the sheep as an animal model. METHODS: Posterior vaginal implantation by means of episiotomy was used to implant 8 ewes which were evaluated macroscopically and histologically at 3 months (n = 4) and 6 months (n = 4) post-surgery. In previous pilot studies anterior vaginal implantation was evaluated, as well as different synthetic mesh materials, sizes and fixation methods (n = 1 to 3) during three weeks. In all cases a clinical evaluation of the animal was performed. RESULTS: A reduction in the mesh size (Synthetic PP Mesh-1) together with precise application of the surgical glue Histoacryl to fix the mesh yielded significantly better histocompatibility results (P < 0.01) compared to larger size or other fixation methods. CONCLUSION: The combination of Synthetic PP Mesh-1 with Histoacryl offered a high degree of graft integration without vaginal ulceration and a minimal foreign body reaction, being the sheep a proper animal model to test these types of medical devices.

Poly(vinyl alcohol) membranes for adhesion prevention.

The abnormal joining of anatomic structures after abdominal and pelvic surgery can lead to such major complications as bowel obstruction or infertility. Poly(vinyl alcohol) (PVA) membranes and hydrogels were placed over the injured tissue to act as a physical barrier and prevent such adhesions from occurring in a rabbit sidewall model. The membranes were sutured into place to prevent their slipping or curling on the moist tissue. Various in vitro experiments (including testing for swelling and mechanical strength) were conducted in order to better understand the behavior of these membranes in the wound. The results showed that both the PVA membranes and PVA hydrogels significantly reduced the number and severity of adhesions in the rabbit sidewall model, and even indicated a distinct improvement over SEPRAFILM as antiadhesion barriers. Contact-angle measurements were taken in order to evaluate the surface properties of the membranes and hydrogels. Three approaches were taken to render the membranes more bioadhesive, and forego the need for future additional suturing: imprinting a texture onto the membrane, coating the membrane with carboxy methyl cellulose (CMC), and producing bi-layered, porous PVA membranes through a process of lyophilization. Though the surface of the PVA hydrogels is more hydrophilic than the surface of the PVA membranes, neither would adhere untreated to moist tissue. However, all three approaches aimed at improving their bioadhesion yielded excellent results and demonstrated that PVA could indeed be considered a viable method of adhesion prevention.

A hydrogel for adhesion prevention: characterization and efficacy study in a rabbit uterus model.

OBJECTIVE: Postoperative peritoneal adhesions following gynaecological surgery remain a clinically relevant problem. One approach to prevent adhesion formation is to apply physical barriers such as hydrogels. STUDY DESIGN: A physically crosslinked polyvinyl alcohol and carboxymethylcellulose (PVA/CMC) hydrogel (A-Part) was characterized in vitro. Three different traumatization methods were evaluated in a rabbit uterine study. To determine its anti-adhesion efficacy, the hydrogel was first tested in an in vivo pilot study and then in a larger trial to compare it with icodextrin 4% solution (Adept) and controls. RESULTS: Rheological measurements showed an increased elasticity of the hydrogel after freezing. In vivo experiments revealed a clear reduction in incidence, extent and severity of adhesions compared to the icodextrin 4% solution and the untreated control group. CONCLUSIONS: These results warrant further investigation of the PVA/CMC A-Part hydrogel in clinical trials focused on gynaecological procedures.

In-vivo studies on intraperitoneally administrated poly(vinyl alcohol).

The fate of poly(vinyl alcohol) (PVA, 195,000 g/mol) was studied in rabbits and nude mice after intraperitoneal (i.p.) administration. In-vivo fluorescence imaging using nude mice allowed for studies of tetramethylrhodamine labeled PVA distribution in the body and tracking the urinary excretion. The excreted PVA was studied in detail after collecting the urine of rabbits over a time period of 28 days. The PVA was separated from the urine by dialysis and analyzed by FTIR spectroscopy, (1)H-NMR spectroscopy, and size exclusion chromatography (SEC). Even after extensive dialysis, it was found that the excreted PVA showed a characteristic brownish color. The spectroscopic techniques revealed that this color was caused by the urine pigment (a metabolite of bilirubin) that could not be separated completely from the PVA. SEC showed unambiguously that the PVA with the very high molar mass had a glomerular permeability in the kidneys. Simultaneously, histological studies of the kidneys and the liver demonstrated that the tissues did not show any obvious damage.

The new adhesion prophylaxis membrane A-part--from in vitro testing to first in vivo results.

INTRODUCTION: Formation of postoperative intra-abdominal adhesions is a severe problem in surgery. Apart from standard surgical procedures, a variety of different substances is available to prevent adhesions, but no universal method has been developed so far. A membrane consisting of polyvinyl alcohol (PVA) and carboxymethylcellulose (CMC) has been demonstrated to be antiadhesive. Here, the in vitro testing and first in vivo results in a rabbit sidewall model are reported. MATERIALS AND METHODS: A-part membrane contains a PVA/CMC mixture in a thickness of 40 microm. The composition, dissolution, tensile strength, and elasticity were examined to characterize the membrane in vitro. Experiments in vivo were carried out using a 'rabbit sidewall model' in which a standardized peritoneal trauma was covered with a 5 x 6 cm A-part membrane. Adhesion formation in A-part-treated animals was compared with that in Adept (15 mL/kg body weight) and untreated controls. RESULTS: An 80/20 PVA/CMC mixture forms a stable, elastic, transparent membrane, which can easily be placed intraoperatively. The dissolution shows a half-life of about 2 weeks [day 15: (45.1 +/- 4.9)% SD], which affords good adhesion protection during the initial critical phase of adhesion formation. In wet conditions, the membrane follows abdominal movements without tearing (tensile strength 5.0 +/- 4.2 N/cm SD; elasticity 29.5%). In a rabbit sidewall model, A-part membrane significantly reduced adhesion development by (83.1 +/- 31.5)% SD compared with the control and the Adept group (p < 0.001). CONCLUSION: The properties of the A-part membrane suggest that it may be useful as an antiadhesive in surgery. A-part is effective in in vivo testing as determined in a rabbit sidewall model.

Polyvinyl alcohol gel prevents abdominal adhesion formation in a rabbit model.

OBJECTIVE: To evaluate the function and biocompatibility of the new adhesion barrier PVA gel (polyvinyl alcohol + carboxymethylated cellulose) in the prevention of postsurgical peritoneal adhesions in a rabbit sidewall model. To evaluate and compare the routinely used 4% icodextrin. DESIGN: A prospective randomized controlled study was designed to evaluate the effectiveness of PVA gel in reducing postoperative adhesion formation. SETTING: Clinical laboratory in Germany. ANIMAL(S): Eighty female albino rabbits (HM Small Russian; 2.4-3.6 kg). INTERVENTION(S): All animals underwent trauma of the abdominal sidewall at the clinical laboratory. The PVA gel was placed at the sidewall defect in 50 cases. In two further groups, 18 animals had no treatment (control group), and 12 animals were treated with 4% icodextrin. MAIN OUTCOME MEASURE(S): Biocompatibility, mechanical properties of PVA gel, adhesion development, and device handling were observed. RESULT(S): The PVA gel showed good biocompatibility, no side effects, and excellent adhesion prevention. Although 100% of the untreated control group as well as the animals treated with 4% icodextrin developed adhesion formation, only around 25% of those rabbits that were treated with PVA gel showed adhesions. CONCLUSION(S): These data show that PVA gel functions as an excellent adhesion barrier.