Physicochemical and biological characterization of magnetic nanoparticles for biomedical applications

The overall goal of this project was the biological characterization by in vivo and in vitro testing of magnetic nanoparticles that can be used for various applications. The aim of this work was to understand which of the synthesized magnetic nanoparticles could be more suitable to be used as a carrier or platform for various applications in different scientific fields. Two different kinds of magnetic nanoparticles were developed: naked iron-oxide nanoparticles and silica or silica-based coated nanoparticles (core shell-type nanoparticles). Magnetic nanoparticles were prepared using a coprecipitation method. The structure, phase composition, physicochemical and surface properties, magnetic susceptibility, and release in vitro of MNPs were characterized by transmission electron microscopy, x-ray diffraction, scanning electron microscopy-energy dispersive x-ray spectroscopy, and a vibrating sample magnetometer. In vivo toxicity, in vitro toxicity, ROS production and genotoxicity were investigated. Therapeutic effects were evaluated by cell viability assays and flow cytometry assays. The tools developed in this thesis spanned a range of physical-chemical, biological and magnetic aspects and incorporate innovations on a nanometric range of scales. MNP-based technologies appear to hold a significant potential for a myriad of biomedical applications and the toxic potential of MNPs cannot be overlooked. For this reason we carried out different physicochemical and biological characterization of MNPs to identify a safe dose and formulation of MNPs. Understanding the relationship between the physicochemical properties of MNP constructs and their behavior will induce full translational potential of these nanoparticles. The magnetic nanoparticles prepared in this study have good biocompatibility and are suitable for further application in tumor hyperthermia

Biophysical and biomechanical properties of cartilage

Cartilage is a connective tissue that covers the surfaces of bones in joints and provides a smooth gliding surface for movement. It is characterized by specific biophysical properties that allow it to withstand compressive loads, distribute mechanical forces, and maintain tissue integrity. The bi-ophysical properties of cartilage are primarily determined by its extracellular matrix, which is composed of collagen fibers, proteoglycans, and water. The collagen fibers provide tensile strength, the proteoglycans provide compressive resistance, and the water content provides lubrication and shock absorption. The potential for greater knowledge of cartilage function through refinement and engineering-level understanding could inform the design of interventions for cartilage dysfunction and pathology. The aim is to assist to present basic principles of cartilage modeling and discussing the underlying physics and assumptions with relatively simple settings, and also it presents the derivation of multiphase cartilage models that are consistent with the discussions. Furthermore, modern developments align the structure captured in the models with observed complexities. The interactions between these components and the surrounding tissues regulate cartilage biomechanics and contribute to its ability to resist damage and repair itself. Alterations in the biophysical prop-erties of cartilage can lead to degenerative joint diseases such as osteoarthritis, highlighting the importance of understanding cartilage structure and function for the development of effective therapeutic strategies

Evolving management of adolescent varicocele

OBJECTIVE: To review the evolution in indications for treatment and treatment modalities for adolescent varicocele at our centre, and evaluate the impact of varicocelectomy on final outcome. PATIENTS AND METHODS: Between 1995 and 2006, we treated 242 left varicoceles. Preoperative assessment included clinical evaluation, measurement of testicular volumes, and colour-Doppler ultrasound (CDUS). A subinguinal varicocelectomy was performed in 124 patients (group A), and a laparoscopic non-artery-sparing Palomo procedure in the remaining 118 (group B). In group B patients, CDUS was also used to investigate the functional anatomy of varicocele, and all the veins found to be refluxing were divided during surgery. The two groups were compared with regard to indications for surgery and outcome. RESULTS: Over time the proportion of patients operated on because of testicular growth retardation increased. Persistence/recurrence rate was comparable between the two groups. In 13% of group B patients, the deferential vein was found to be refluxing on preoperative CDUS and was divided at surgery. Hydrocele rate was higher in group A, unless the vaginalis was excised and everted during varicocelectomy. About 75% of patients with preoperative left testicular growth failure experienced postoperative catch-up growth, irrespective of treatment. CONCLUSION: Indications for treatment are still evolving. Varicocele can successfully be treated in the majority of cases by either a laparoscopic or subinguinal approach. Both techniques require care, and CDUS can aid in the decision making. Most patients with preoperative testicular growth failure experience postoperative catch-up growth

Transabdominal pre-peritoneal mesh in inguinal hernia repair in elderly: end point of our experience

BACKGROUND: Aim of this study is to present our standardized laparoscopic transabdominal preperitoneal hernia repair (TAPP) technique, and to study our experience in the elderly as far as concerns preoperative and postoperative variables. METHODS: We described our standardized TAPP technique according with Stuttgart technique [1], and we evalutated our team's experience in TAPP inguinal hernia repair in elderly (> 65 yrs) and in young patients (< 65 yrs). RESULTS: We retrospectively reviewed our Surgery Division's experience about TAPP; we included in our study 185 patients. The sample was subdivided in two groups: TAPP Group (< 65 years patients) and TAPPe Group (> 65 years patients). TAPP Group was composed by 154 patients and TAPPe Group of 31 patients. According with literature, in this subgroup recurrence rate (3,2%), early and delayed complications and mean operative time (86 min). There were no major vascular or intestinal complications. At the moment follow-up is 31 months. There were no incisional hernias on umbilical trocar. Mean satisfaction rate was excellent also in elderly patients. CONCLUSIONS: According with literature, in our experience TAPP technique is a safe and feasible procedure, even in elderly patients

Evaluation of esophageal motility using multichannel intraluminal impedance in healthy children and children with gastroesophageal reflux: comments

Abstract OBJECTIVE: : Multichannel intraluminal impedance (MII) directly evaluates esophageal bolus transport. There is a good correlation between MII and manometry in healthy adults, but there are no reports concerning children.The aim of the present study was to determine normal values of esophageal motility using only impedance measurements in healthy children and in a pediatric population with gastroesophageal reflux (GER). PATIENTS AND METHODS: : We described in the present study 60 children submitted to pH-MII for 24 hours for suspected GER. Patients were divided into 2 different groups on the basis of their pH-MII report. Group 1 patients showed acid GER, whereas group 2 patients had negative pH-MII analysis for GER despite symptoms. We described impedance reflux and motility parameters on 10 standardized swallows: number of reflux, mean acid clearing time, median bolus clearing time, bolus presence time, total bolus transit time, segmental transit time, and total propagation velocity. RESULTS: : In group 1, the median mean acid clearing time was 151 seconds, whereas the median mean bolus clearing time was 25 seconds. In group 2 patients, all of the reflux parameters were normal. In group 1 the median bolus presence time at each measuring site, the median total bolus transit time, and the median segmental transit time were significantly greater and total propagation velocity lower than values reported in group 2 (P < 0.001), if compared with those described for adult patients. CONCLUSIONS: : The pH-MII is an ideal test in children because it studies GER with its characteristics and motility pattern. Our report summarizes for the first time impedance motility parameters in healthy children

A simple technique of oblique anastomosis can prevent stricture formation in primary repair of esophageal atresia

Background: Anastomotic stricture is an important problem after esophageal atresia (EA) repair. This study evaluates a technique of oblique esophageal anastomosis without use of a flap in order to prevent stricture formation. Methods: Medical records of 16 patients (14 with EA type III and 2 with EA type IV Ladd-Gross classification) who underwent primary repair of EA at birth without anastomotic tension were reviewed, evaluating long-term follow-up results. All patients were studied with esophageal contrast study, pH-multichannel intraluminal impedance, and endoscopy. The incidence of complications and their management were analysed. Results: Contrast esophagogram and esophagoscopy always showed regular patency of the suture line. Conclusions: Our technique of oblique anastomosis is simple, safe, and effective in preventing stricture formation even in the long-term follow-up

Laparoscopic Surgery of Deferential Reflux in Pediatric and Adolescent Varicocele

BACKGROUND: This study aimed to assess whether deferential reflux in pediatric and adolescent varicocele can be successfully treated laparoscopically. MATERIALS AND METHODS: Since 2001 at our institution, 148 boys were evaluated for a left varicocele. Preoperatively,all the patients underwent ultrasound scan assessment of testicular volume and color-Doppler US (CDUS)to rule out reflux into the internal spermatic vein (ISV), deferential vein, or cremasteric vein. Boys with ISV reflux were treated by laparoscopic transperitoneal Palomo; boys with isolated deferential reflux or associated to ISV reflux were laparoscopically managed adding to the former procedure, coagulation or clipping of refluxing deferential veins. RESULTS: Reflux in both the ISV and the deferential vein was observed in 21 (14.1%) out 148 boys with varicocele.Only one case (0.6%) of varicocele was caused by an isolated deferential reflux. No reflux in the cremasteric vein was observed. After a median follow up period of 2 years (range, 6 months-5 years), none of our patients with deferential reflux experienced varicocele recurrence either clinically or according to CDUS scanning.No testicular atrophy was observed. CONCLUSION: Our diagnostic approach is a rigorous standard for identifying all the venous systems concurring with the varicocele. Our proposed technique with laparoscopic interruption or coagulation of deferential veins when proved by CDUS to be refluxing may allow successful treatment for most varicoceles. This method allows reduction in recurrence of varicocele due to a missed deferential reflux