Federico Soria - Academia.edu (original) (raw)

Papers by Federico Soria

Animals, Jan 31, 2022

The killer whale (Orcinus orca, Linnaeus, 1958) is an odontocete and is the largest member of the... more The killer whale (Orcinus orca, Linnaeus, 1958) is an odontocete and is the largest member of the family Delphinidae. Free-ranging animals are capable of considerable physical efforts, either as acute bursts or sustained speeds during foraging, diving or protracted long-distance migrations. In this article, the morphology of a plastinated heart of a killer whale and functional adaptations of the gross anatomy in the context of a variety of physiologic demands is evaluated. The four chambers, their content, respective openings and communicating passages are defined based on a specimen used for plastination and thus available for extended and detailed anatomic studies.

Polymers, Aug 16, 2022

The insertion of a ureteral stent provides acute care by restoring urine flow and alleviating uri... more The insertion of a ureteral stent provides acute care by restoring urine flow and alleviating urinary retention or dysfunction. The problems of encrustation, bacterial colonization and biofilm formation become increasingly important when ureteral stents are left in place for a longer period of time. One way to reduce encrustation and bacterial adherence is to modify the stent surface with a diamond-like carbon coating, in combination with copper doping. The biocompatibilities of the Elastollan ® base material and the a-C:H/Cu-mulitilayer coating were tested in synthetic urine. The copper content in bladder tissue was determined by atomic absorption spectroscopy and in blood and in urine by inductively coupled plasma mass spectrometry. Encrustations on the materials were analyzed by scanning electron microscopy, energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. A therapeutic window for copper ions of 0.5-1.0 mM was determined to kill bacteria without affecting human urothelial cells. In the rat animal model, it was found that copper release did not reach toxic concentrations in the affecting tissue of the urinary tract or in the blood. The encrustation behavior of the surfaces showed that the roughness of the amorphous carbon layer with the copper doping is probably the causal factor for the higher encrustation.

Scientific Reports, Jan 11, 2018

Miniaturization of ureteroscopy materials is intended to decrease tissue damage. However, tissue ... more Miniaturization of ureteroscopy materials is intended to decrease tissue damage. However, tissue hypoxia and the gross and microscopic effects on tissue have not been adequately assessed. We compared the gross and microscopic effects of micro-ureteroscopy (m-URS) and conventional ureteroscopy (URS) on the urinary tract. We employed 14 pigs of the Large White race. URS was performed in one of the ureters with an 8/9.8 F ureteroscope, while a 4.85 F m-URS sheath was used in the contralateral ureter. Gross assessment of ureteral wall damage and ureteral orifice damage was performed. For microscopic assessment hematoxylin-eosin staining and immunohistochemistry for detection of tissue hypoxia were conducted. Regarding the macroscopic assessment of ureteral damage, substantial and significant differences were recorded using URS (C = 0.8), but not with m-URS. Microscopic assessment after staining with hematoxylin-eosin revealed greater epithelial desquamation in the URS group (p < 0.05). Pimonidazole staining revealed greater hypoxia in the epithelial cells than in the remainder of the ureteral layers. We conclude that m-URS causes less damage to the ureteral orifice than URS. Histopathological findings show m-URS reduces ureteral epithelial damage compared with conventional ureteroscopy. Both URS and m-URS cause cellular hypoxia. As a result of technological advances in ureteroscopes, imaging systems and ancillary devices, ureteroscopy has become one of the fundamental techniques used in endourology 1 . The new ureteroscopes allow us to maintain good operating conditions, with good irrigation flow, good visibility and the capacity to introduce ancillary instruments, using instruments of increasingly smaller calibers. Miniaturization should preserve the efficacy of the technique while reducing the complications derived from tissue damage caused by the ureteroscope within the urinary tract. Damage to the ureteral wall has been associated with complications such as hematuria, postoperative edema or renoureteral colic. Vesicoureteral reflux, in turn, has been associated with loss of the valve mechanism of the orifice and intramural ureter. Furthermore, some authors have related the degree of ureteral damage to the need for postoperative ureteral stent placement and its duration 2 . On the other hand, ureteral stricture may also have an inflammatory and/or ischemic component 3 . To further reduce ureteroscope caliber, micro-ureteroscopy (m-URS) was first described in 2014 as a ureteroscope using a 4.85 F (French) sheath of the micropercutaneous surgery set for the treatment of distal ureteral lithiasis in women, with satisfactory results . Recently, Utanğaç et al. performed m-URS in a series of 11 children with a mean age of 55.1 months 6 . The authors reported that ureteral access in the pediatric patients could be carried out in all cases without preoperative ureteral stenting or dilatation of the ureteral orifice. No comparative studies reporting scientific evidence at the micro-or macroscopic level of the ureteral effects of ureteroscopes of different calibers have been published. Therefore, the purpose of this experimental study was to determine whether micro-ureteroscopy performed with the 4.85 F access sheath of the micro-Perc ® set

British Journal of Surgery, 2021

INTRODUCTION To assess the release rate of Mitomycin C (MMC) after its adherence to a biodegradab... more INTRODUCTION To assess the release rate of Mitomycin C (MMC) after its adherence to a biodegradable ureteral stent (BraidStent™-MMC) by dip coating in order to evaluate its potential application as an adjuvant treatment for upper tract urothelial carcinoma. MATERIAL AND METHODS The dip coating technique is applied to a total of 10 fragments of the BraidStent™ catheter which has a polymeric matrix as a coating. Each 3 cm fragment is immersed 10 times in pure MMC crystallising in methanol and finally obtaining the formation of microlayers on its surface. After drying, each fraction of the stent is immersed in 5 ml of artificial urine to study its interaction with this medium. The samples remain in an orbital shaker at 36ºC and the medium is exchanged under sterile conditions after 12, 24, 48, 48, 72, 96 and 120h. At each replacement, the remaining urine is analysed by HPLC-DAD to quantify the presence of the cytotoxic agent. RESULTS During the first 12h, MMC is completely released ...

Springer eBooks, 2022

Considering the impact on the quality of life of patients caused by double-J stents (DJS), differ... more Considering the impact on the quality of life of patients caused by double-J stents (DJS), different stent designs have been developed focusing mainly on the decrease or suppression of vesicoureteral reflux (VUR) and the reduction of bladder trigone irritation, for the improvement of patient comfort [1-4]. Many of these designs are based on changes at the distal end, such as the attachment of antireflux membranes and valves, their replacement by less voluminous designs or the complete removal of this section to create intraureteral stents [5-10]. 2 Antireflux Membranes and Valves Antireflux membranes and valves are devices incorporated to the distal end of a standard DJS design, with the purpose of preventing intraluminal reflux through the internal channel of the stent. There are two variants, the antireflux-membrane valve and the polymeric flap valve [5, 6, 11]. The antireflux membrane valve consists of a transparent silicone membrane in the shape of a pouch, that is attached at the vesical end of a DJS, wrapped around the outlet of the internal channel and the lateral orifices [5, 11, 12] (Fig. 1). This design is currently available for clinical use and its antireflux mechanism works as a one-way valve, automatically collapses as the bladder pressure increases thus

Springer eBooks, 2022

Double J stents are used in a wide variety of scenarios, which we will divide into two groups of ... more Double J stents are used in a wide variety of scenarios, which we will divide into two groups of indications for didactic purposes: prophylactic and therapeutic. 1.1 Prophylactic Indications The insertion of a double J stent can prevent the advent of perioperative complications in specific procedures involving the upper urinary tract. These interventions are mainly focused on urinary stone management, followed by reconstructive procedures.

J Vet Med Educ, 2014

This article reports on the face, content, and construct validity of a new realistic composite si... more This article reports on the face, content, and construct validity of a new realistic composite simulator (Simuldog) used to provide training in canine gastrointestinal flexible endoscopy. The basic endoscopic procedures performed on the simulator were esophagogastroduodenoscopy (EGD), gastric biopsy (GB), and gastric foreign body removal (FBR). Construct validity was assessed by comparing the performance of novices (final-year veterinary students and recent graduates without endoscopic experience, n ¼ 30) versus experienced subjects (doctors in veterinary medicine who had performed more than 50 clinical upper gastrointestinal endoscopic procedures as a surgeon, n ¼ 15). Tasks were scored based on completion time, and specific rating scales were developed to assess performance. Internal consistency and inter-rater agreement were assessed. Face and content validity were determined using a 5-point Likert-type scale questionnaire. The novices needed considerably more time than the experts to perform EGD, GB, and FBR, and their performance scores were significantly lower (p < .010). Inter-rater agreement and the internal validity of the rating scales were good. Face validity was excellent, and both groups agreed that the endoscopy scenarios were very realistic. The experts highly valued the usefulness of Simuldog for veterinary training and as a tool for assessing endoscopic skills. Simuldog is the first validated model specifically developed to be used as a training tool for endoscopy techniques in small animals.

British Journal of Surgery

INTRODUCTION The aim of this study is to assess the effectiveness of heparin to inhibit the devel... more INTRODUCTION The aim of this study is to assess the effectiveness of heparin to inhibit the development of early bacteriuria as a coating for biodegradable ureteral stents. MATERIAL AND METHODS The BraidStent®-H biodegradable stent, whose heparin coating is incorporated by dip coating, was chosen for this study. Twenty-four swine were randomly divided into two groups: 12 animals underwent unilateral placement of the BraidStent®-H and 12 were fitted with a standard double-j stent (DJS). Bacteriuria is comparatively analyzed over time by consecutive urine sampling at 0, 1, 3, 6, 12, 24 and 48 hours. In addition, the concentration of heparin released in vitro in artificial urine at 0, 3, 6, 12, 24, 48, 72, 92 and 120 hours is determined via ELISA. RESULTS BraidStent®-H generates a significantly lower bacteriuria rate than a DJS at 6 and 12 hours. Heparin coating shows a significant delaying effect on the onset of bacteriuria, reaching 100% of the animals at 48 hours, compared to the DJ...

Polymers

Urothelial tumour of the upper urinary tract is a rare neoplasm, but unfortunately, it has a high... more Urothelial tumour of the upper urinary tract is a rare neoplasm, but unfortunately, it has a high recurrence rate. The reduction of these tumour recurrences could be achieved by the intracavitary instillation of adjuvant chemotherapy after nephron-sparing treatment in selected patients, but current instillation methods are ineffective. Therefore, the aim of this in vitro study is to evaluate the cytotoxic capacity of a new instillation technology through a biodegradable ureteral stent/scaffold coated with a silk fibroin matrix for the controlled release of mitomycin C as an anti-cancer drug. Through a comparative study, we assessed, in urothelial carcinoma cells in a human cancer T24 cell culture for 3 and 6 h, the cytotoxic capacity of mitomycin C by viability assay using the CCK-8 test (Cell counting Kit-8). Cell viability studies in the urothelial carcinoma cell line confirm that mitomycin C embedded in the polymeric matrix does not alter its cytotoxic properties and causes a sig...

Urinary Stents

The urinary tract is a highly complex, dynamic and variable environment that renders the developm... more The urinary tract is a highly complex, dynamic and variable environment that renders the development of urinary stents extremely challenging. It is mandatory that previous to clinical trials, innovations in urinary medical devices are tested in a preclinical context. The steps of translational research in this regard includein silico,in vitro,ex vivoandin vivoassessments. In this chapter, a critical review of the in vitro stent assessment models is performed, outlining briefly their strengths and weaknesses. Subsequently, a discussion concerning the available animal models for urinary stent evaluation is made with the aim of providing a critical guide for experimental preclinical evaluation of urological devices.

Polymers

A major limitation of the treatment of low-grade upper tract urothelial carcinoma is the difficul... more A major limitation of the treatment of low-grade upper tract urothelial carcinoma is the difficulty of intracavitary instillation of adjuvant therapy. Therefore, the aim of this in vitro study was to develop and to assess a new design of biodegradable ureteral stent coated with a silk fibroin matrix for the controlled release of mitomycin C as a chemotherapeutic drug. For this purpose, we assessed the coating of a biodegradable ureteral stent, BraidStent®, with silk fibroin and subsequently loaded the polymeric matrix with two formulations of mitomycin to evaluate its degradation rate, the concentration of mitomycin released, and changes in the pH and the weight of the stent. Our results confirm that the silk fibroin matrix is able to coat the biodegradable stent and release mitomycin for between 6 and 12 h in the urinary environment. There was a significant delay in the degradation rate of silk fibroin and mitomycin-coated stents compared to bare biodegradable stents, from 6–7 week...

Polymers

Background: When trying to modify urinary stents, certain pre-clinical steps have to be followed ... more Background: When trying to modify urinary stents, certain pre-clinical steps have to be followed before clinical evaluation in humans. Usually, the process starts as an in silico assessment. The urinary tract is a highly complex, dynamic and variable environment, which makes a computer simulation closely reflecting physiological conditions extremely challenging. Therefore, the pre-clinical evaluation needs to go through further steps of in vitro, ex vivo and in vivo assessments. Methods and materials: Within the European Network of Multidisciplinary Research to Improve Urinary Stents (ENIUS), the authors summarized and evaluated stent assessment models in silico, in vitro, ex vivo and in vivo. The topic and relevant sub-topics were researched in a systematic literature search in Embase, Scope, Web of Science and PubMed. Clinicaltrials.gov was consulted for ongoing trials. Articles were selected systematically according to guidelines with non-relevant, non-complete, and non-English o...

Expert Review of Medical Devices

Potential strategies to prevent encrustations on urinary stents and catheters-thinking outside th... more Potential strategies to prevent encrustations on urinary stents and catheters-thinking outside the box: A European Network of Multidisciplinary Research to Improve Urinary Stents (ENIUS) Initiative *

Actas de las XXXIX Jornadas de Automática, Badajoz, 5-7 de Septiembre de 2018, 2020

Journal of Endourology, 2021

Objective: The aim is to assess the effectiveness of a biodegradable antireflux ureteral stent wi... more Objective: The aim is to assess the effectiveness of a biodegradable antireflux ureteral stent with heparin coating in a comparative study (BraidStent Ò-H) in an animal model for the treatment of iatrogenic ureteral perforation. Materials and Methods: A total of 24 female pigs underwent initial endoscopic, nephrosonographic, and contrast fluoroscopy assessment of the urinary tract. Afterward, unilateral iatrogenic perforation in proximal ureter model was performed. Then the animals were randomly assigned to Group-I, in which a double-pigtail stent was placed for 6 weeks, or Group-II, in which a BraidStent-H a biodegradable heparin-coated stent was placed. Follow-up assessments were performed at 1 and 6 weeks and 5 months. Results: In terms of therapeutic effectiveness, complete resolution was observed in 95.8% of Group-I animals and 87.5% in Group-II. No animals in Group-II showed vesicoureteral reflux (VUR) during the study; statistical significance was observed at 1 and 6 weeks versus Group-I. All stents in Group-II degraded without producing obstructive fragments and allowed distal ureteral peristalsis. Heparin coating was not efficient to reduce asymptomatic bacteriuria between groups. Pathologic assessment did not show any significance in the global score, but did in the ''fibrosis in muscular layer'' parameter, at the ureteral perforation healing area; Group-II showed higher healing quality. Conclusions: The biodegradable intraureteral BraidStent Ò-H is highly effective for the minimally invasive treatment of ureteral perforation, since it displays controlled and predictable degradation, avoiding the development of VUR as well as irritation of the bladder trigone. Unfortunately, heparin coating was not effective in avoiding stent-associated bacteriuria.

Animals, Jan 31, 2022

The killer whale (Orcinus orca, Linnaeus, 1958) is an odontocete and is the largest member of the... more The killer whale (Orcinus orca, Linnaeus, 1958) is an odontocete and is the largest member of the family Delphinidae. Free-ranging animals are capable of considerable physical efforts, either as acute bursts or sustained speeds during foraging, diving or protracted long-distance migrations. In this article, the morphology of a plastinated heart of a killer whale and functional adaptations of the gross anatomy in the context of a variety of physiologic demands is evaluated. The four chambers, their content, respective openings and communicating passages are defined based on a specimen used for plastination and thus available for extended and detailed anatomic studies.

Polymers, Aug 16, 2022

The insertion of a ureteral stent provides acute care by restoring urine flow and alleviating uri... more The insertion of a ureteral stent provides acute care by restoring urine flow and alleviating urinary retention or dysfunction. The problems of encrustation, bacterial colonization and biofilm formation become increasingly important when ureteral stents are left in place for a longer period of time. One way to reduce encrustation and bacterial adherence is to modify the stent surface with a diamond-like carbon coating, in combination with copper doping. The biocompatibilities of the Elastollan ® base material and the a-C:H/Cu-mulitilayer coating were tested in synthetic urine. The copper content in bladder tissue was determined by atomic absorption spectroscopy and in blood and in urine by inductively coupled plasma mass spectrometry. Encrustations on the materials were analyzed by scanning electron microscopy, energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. A therapeutic window for copper ions of 0.5-1.0 mM was determined to kill bacteria without affecting human urothelial cells. In the rat animal model, it was found that copper release did not reach toxic concentrations in the affecting tissue of the urinary tract or in the blood. The encrustation behavior of the surfaces showed that the roughness of the amorphous carbon layer with the copper doping is probably the causal factor for the higher encrustation.

Scientific Reports, Jan 11, 2018

Miniaturization of ureteroscopy materials is intended to decrease tissue damage. However, tissue ... more Miniaturization of ureteroscopy materials is intended to decrease tissue damage. However, tissue hypoxia and the gross and microscopic effects on tissue have not been adequately assessed. We compared the gross and microscopic effects of micro-ureteroscopy (m-URS) and conventional ureteroscopy (URS) on the urinary tract. We employed 14 pigs of the Large White race. URS was performed in one of the ureters with an 8/9.8 F ureteroscope, while a 4.85 F m-URS sheath was used in the contralateral ureter. Gross assessment of ureteral wall damage and ureteral orifice damage was performed. For microscopic assessment hematoxylin-eosin staining and immunohistochemistry for detection of tissue hypoxia were conducted. Regarding the macroscopic assessment of ureteral damage, substantial and significant differences were recorded using URS (C = 0.8), but not with m-URS. Microscopic assessment after staining with hematoxylin-eosin revealed greater epithelial desquamation in the URS group (p < 0.05). Pimonidazole staining revealed greater hypoxia in the epithelial cells than in the remainder of the ureteral layers. We conclude that m-URS causes less damage to the ureteral orifice than URS. Histopathological findings show m-URS reduces ureteral epithelial damage compared with conventional ureteroscopy. Both URS and m-URS cause cellular hypoxia. As a result of technological advances in ureteroscopes, imaging systems and ancillary devices, ureteroscopy has become one of the fundamental techniques used in endourology 1 . The new ureteroscopes allow us to maintain good operating conditions, with good irrigation flow, good visibility and the capacity to introduce ancillary instruments, using instruments of increasingly smaller calibers. Miniaturization should preserve the efficacy of the technique while reducing the complications derived from tissue damage caused by the ureteroscope within the urinary tract. Damage to the ureteral wall has been associated with complications such as hematuria, postoperative edema or renoureteral colic. Vesicoureteral reflux, in turn, has been associated with loss of the valve mechanism of the orifice and intramural ureter. Furthermore, some authors have related the degree of ureteral damage to the need for postoperative ureteral stent placement and its duration 2 . On the other hand, ureteral stricture may also have an inflammatory and/or ischemic component 3 . To further reduce ureteroscope caliber, micro-ureteroscopy (m-URS) was first described in 2014 as a ureteroscope using a 4.85 F (French) sheath of the micropercutaneous surgery set for the treatment of distal ureteral lithiasis in women, with satisfactory results . Recently, Utanğaç et al. performed m-URS in a series of 11 children with a mean age of 55.1 months 6 . The authors reported that ureteral access in the pediatric patients could be carried out in all cases without preoperative ureteral stenting or dilatation of the ureteral orifice. No comparative studies reporting scientific evidence at the micro-or macroscopic level of the ureteral effects of ureteroscopes of different calibers have been published. Therefore, the purpose of this experimental study was to determine whether micro-ureteroscopy performed with the 4.85 F access sheath of the micro-Perc ® set

British Journal of Surgery, 2021

INTRODUCTION To assess the release rate of Mitomycin C (MMC) after its adherence to a biodegradab... more INTRODUCTION To assess the release rate of Mitomycin C (MMC) after its adherence to a biodegradable ureteral stent (BraidStent™-MMC) by dip coating in order to evaluate its potential application as an adjuvant treatment for upper tract urothelial carcinoma. MATERIAL AND METHODS The dip coating technique is applied to a total of 10 fragments of the BraidStent™ catheter which has a polymeric matrix as a coating. Each 3 cm fragment is immersed 10 times in pure MMC crystallising in methanol and finally obtaining the formation of microlayers on its surface. After drying, each fraction of the stent is immersed in 5 ml of artificial urine to study its interaction with this medium. The samples remain in an orbital shaker at 36ºC and the medium is exchanged under sterile conditions after 12, 24, 48, 48, 72, 96 and 120h. At each replacement, the remaining urine is analysed by HPLC-DAD to quantify the presence of the cytotoxic agent. RESULTS During the first 12h, MMC is completely released ...

Springer eBooks, 2022

Considering the impact on the quality of life of patients caused by double-J stents (DJS), differ... more Considering the impact on the quality of life of patients caused by double-J stents (DJS), different stent designs have been developed focusing mainly on the decrease or suppression of vesicoureteral reflux (VUR) and the reduction of bladder trigone irritation, for the improvement of patient comfort [1-4]. Many of these designs are based on changes at the distal end, such as the attachment of antireflux membranes and valves, their replacement by less voluminous designs or the complete removal of this section to create intraureteral stents [5-10]. 2 Antireflux Membranes and Valves Antireflux membranes and valves are devices incorporated to the distal end of a standard DJS design, with the purpose of preventing intraluminal reflux through the internal channel of the stent. There are two variants, the antireflux-membrane valve and the polymeric flap valve [5, 6, 11]. The antireflux membrane valve consists of a transparent silicone membrane in the shape of a pouch, that is attached at the vesical end of a DJS, wrapped around the outlet of the internal channel and the lateral orifices [5, 11, 12] (Fig. 1). This design is currently available for clinical use and its antireflux mechanism works as a one-way valve, automatically collapses as the bladder pressure increases thus

Springer eBooks, 2022

Double J stents are used in a wide variety of scenarios, which we will divide into two groups of ... more Double J stents are used in a wide variety of scenarios, which we will divide into two groups of indications for didactic purposes: prophylactic and therapeutic. 1.1 Prophylactic Indications The insertion of a double J stent can prevent the advent of perioperative complications in specific procedures involving the upper urinary tract. These interventions are mainly focused on urinary stone management, followed by reconstructive procedures.

J Vet Med Educ, 2014

This article reports on the face, content, and construct validity of a new realistic composite si... more This article reports on the face, content, and construct validity of a new realistic composite simulator (Simuldog) used to provide training in canine gastrointestinal flexible endoscopy. The basic endoscopic procedures performed on the simulator were esophagogastroduodenoscopy (EGD), gastric biopsy (GB), and gastric foreign body removal (FBR). Construct validity was assessed by comparing the performance of novices (final-year veterinary students and recent graduates without endoscopic experience, n ¼ 30) versus experienced subjects (doctors in veterinary medicine who had performed more than 50 clinical upper gastrointestinal endoscopic procedures as a surgeon, n ¼ 15). Tasks were scored based on completion time, and specific rating scales were developed to assess performance. Internal consistency and inter-rater agreement were assessed. Face and content validity were determined using a 5-point Likert-type scale questionnaire. The novices needed considerably more time than the experts to perform EGD, GB, and FBR, and their performance scores were significantly lower (p < .010). Inter-rater agreement and the internal validity of the rating scales were good. Face validity was excellent, and both groups agreed that the endoscopy scenarios were very realistic. The experts highly valued the usefulness of Simuldog for veterinary training and as a tool for assessing endoscopic skills. Simuldog is the first validated model specifically developed to be used as a training tool for endoscopy techniques in small animals.

British Journal of Surgery

INTRODUCTION The aim of this study is to assess the effectiveness of heparin to inhibit the devel... more INTRODUCTION The aim of this study is to assess the effectiveness of heparin to inhibit the development of early bacteriuria as a coating for biodegradable ureteral stents. MATERIAL AND METHODS The BraidStent®-H biodegradable stent, whose heparin coating is incorporated by dip coating, was chosen for this study. Twenty-four swine were randomly divided into two groups: 12 animals underwent unilateral placement of the BraidStent®-H and 12 were fitted with a standard double-j stent (DJS). Bacteriuria is comparatively analyzed over time by consecutive urine sampling at 0, 1, 3, 6, 12, 24 and 48 hours. In addition, the concentration of heparin released in vitro in artificial urine at 0, 3, 6, 12, 24, 48, 72, 92 and 120 hours is determined via ELISA. RESULTS BraidStent®-H generates a significantly lower bacteriuria rate than a DJS at 6 and 12 hours. Heparin coating shows a significant delaying effect on the onset of bacteriuria, reaching 100% of the animals at 48 hours, compared to the DJ...

Polymers

Urothelial tumour of the upper urinary tract is a rare neoplasm, but unfortunately, it has a high... more Urothelial tumour of the upper urinary tract is a rare neoplasm, but unfortunately, it has a high recurrence rate. The reduction of these tumour recurrences could be achieved by the intracavitary instillation of adjuvant chemotherapy after nephron-sparing treatment in selected patients, but current instillation methods are ineffective. Therefore, the aim of this in vitro study is to evaluate the cytotoxic capacity of a new instillation technology through a biodegradable ureteral stent/scaffold coated with a silk fibroin matrix for the controlled release of mitomycin C as an anti-cancer drug. Through a comparative study, we assessed, in urothelial carcinoma cells in a human cancer T24 cell culture for 3 and 6 h, the cytotoxic capacity of mitomycin C by viability assay using the CCK-8 test (Cell counting Kit-8). Cell viability studies in the urothelial carcinoma cell line confirm that mitomycin C embedded in the polymeric matrix does not alter its cytotoxic properties and causes a sig...

Urinary Stents

The urinary tract is a highly complex, dynamic and variable environment that renders the developm... more The urinary tract is a highly complex, dynamic and variable environment that renders the development of urinary stents extremely challenging. It is mandatory that previous to clinical trials, innovations in urinary medical devices are tested in a preclinical context. The steps of translational research in this regard includein silico,in vitro,ex vivoandin vivoassessments. In this chapter, a critical review of the in vitro stent assessment models is performed, outlining briefly their strengths and weaknesses. Subsequently, a discussion concerning the available animal models for urinary stent evaluation is made with the aim of providing a critical guide for experimental preclinical evaluation of urological devices.

Polymers

A major limitation of the treatment of low-grade upper tract urothelial carcinoma is the difficul... more A major limitation of the treatment of low-grade upper tract urothelial carcinoma is the difficulty of intracavitary instillation of adjuvant therapy. Therefore, the aim of this in vitro study was to develop and to assess a new design of biodegradable ureteral stent coated with a silk fibroin matrix for the controlled release of mitomycin C as a chemotherapeutic drug. For this purpose, we assessed the coating of a biodegradable ureteral stent, BraidStent®, with silk fibroin and subsequently loaded the polymeric matrix with two formulations of mitomycin to evaluate its degradation rate, the concentration of mitomycin released, and changes in the pH and the weight of the stent. Our results confirm that the silk fibroin matrix is able to coat the biodegradable stent and release mitomycin for between 6 and 12 h in the urinary environment. There was a significant delay in the degradation rate of silk fibroin and mitomycin-coated stents compared to bare biodegradable stents, from 6–7 week...

Polymers

Background: When trying to modify urinary stents, certain pre-clinical steps have to be followed ... more Background: When trying to modify urinary stents, certain pre-clinical steps have to be followed before clinical evaluation in humans. Usually, the process starts as an in silico assessment. The urinary tract is a highly complex, dynamic and variable environment, which makes a computer simulation closely reflecting physiological conditions extremely challenging. Therefore, the pre-clinical evaluation needs to go through further steps of in vitro, ex vivo and in vivo assessments. Methods and materials: Within the European Network of Multidisciplinary Research to Improve Urinary Stents (ENIUS), the authors summarized and evaluated stent assessment models in silico, in vitro, ex vivo and in vivo. The topic and relevant sub-topics were researched in a systematic literature search in Embase, Scope, Web of Science and PubMed. Clinicaltrials.gov was consulted for ongoing trials. Articles were selected systematically according to guidelines with non-relevant, non-complete, and non-English o...

Expert Review of Medical Devices

Potential strategies to prevent encrustations on urinary stents and catheters-thinking outside th... more Potential strategies to prevent encrustations on urinary stents and catheters-thinking outside the box: A European Network of Multidisciplinary Research to Improve Urinary Stents (ENIUS) Initiative *

Actas de las XXXIX Jornadas de Automática, Badajoz, 5-7 de Septiembre de 2018, 2020

Journal of Endourology, 2021

Objective: The aim is to assess the effectiveness of a biodegradable antireflux ureteral stent wi... more Objective: The aim is to assess the effectiveness of a biodegradable antireflux ureteral stent with heparin coating in a comparative study (BraidStent Ò-H) in an animal model for the treatment of iatrogenic ureteral perforation. Materials and Methods: A total of 24 female pigs underwent initial endoscopic, nephrosonographic, and contrast fluoroscopy assessment of the urinary tract. Afterward, unilateral iatrogenic perforation in proximal ureter model was performed. Then the animals were randomly assigned to Group-I, in which a double-pigtail stent was placed for 6 weeks, or Group-II, in which a BraidStent-H a biodegradable heparin-coated stent was placed. Follow-up assessments were performed at 1 and 6 weeks and 5 months. Results: In terms of therapeutic effectiveness, complete resolution was observed in 95.8% of Group-I animals and 87.5% in Group-II. No animals in Group-II showed vesicoureteral reflux (VUR) during the study; statistical significance was observed at 1 and 6 weeks versus Group-I. All stents in Group-II degraded without producing obstructive fragments and allowed distal ureteral peristalsis. Heparin coating was not efficient to reduce asymptomatic bacteriuria between groups. Pathologic assessment did not show any significance in the global score, but did in the ''fibrosis in muscular layer'' parameter, at the ureteral perforation healing area; Group-II showed higher healing quality. Conclusions: The biodegradable intraureteral BraidStent Ò-H is highly effective for the minimally invasive treatment of ureteral perforation, since it displays controlled and predictable degradation, avoiding the development of VUR as well as irritation of the bladder trigone. Unfortunately, heparin coating was not effective in avoiding stent-associated bacteriuria.