Effectiveness and safety of the radiofrequency ablation of single hyperfunctioning parathyroid lesions suggestive of adenomas in primary hyperparathyroidism.

INTRODUCTION: Radiofrequency ablation (RFA) has emerged as a minimally invasive approach to single parathyroid adenoma in primary hyperparathyroidism; however, there is limited evidence on its effectiveness. OBJECTIVE: To evaluate the effectiveness and safety of RFA to treat hyper-functioning parathyroid lesions suggestive of adenomas. MATERIAL AND METHODS: A prospective study was conducted in consecutive patients with primary hyperparathyroidism treated with RFA for single parathyroid lesions in our reference center between November 2017 and June 2021. Pre-treatment (baseline) and follow-up analytical data were gathered on total protein-adjusted calcium, parathyroid hormone [PTH], phosphorus, and 24-h urine calcium. Effectiveness was defined as complete response (normal calcium and PTH), partial response (reduced but not normalized PTH with normal serum calcium), or disease persistence (elevated calcium and PTH). SPSS 15.0 was used for statistical analysis. RESULTS: Four of thirty-three enrolled patients were lost to the follow-up. The final sample comprised 29 patients (22 females) with mean age of 60.93 ± 13.28 years followed up for a mean of 16.29 ± 7.23 months. Complete response was observed in 48.27%, partial response in 37.93%, and hyperparathyroidism persistence in 13.79%. Serum calcium and PTH levels were significantly lower at 1 and 2 years of post-treatment than at baseline. Adverse effects were mild, with two cases of dysphonia (self-limited in one patient) and no cases of hypocalcaemia or hypoparathyroidism. CONCLUSION: RFA may be a safe and effective technique to treat hyper-functioning parathyroid lesions in selected patients.

Differences in multi-echo chemical shift encoded MRI proton density fat fraction estimation based on multifrequency fat peaks selection in non-alcoholic fatty liver disease patients.

AIM: To compare the performance of multi-echo chemical-shift-encoded (MECSE) magnetic resonance imaging (MRI) proton density fat fraction (PDFF) estimation, considering three different fat frequency peak combinations, for the quantification of steatosis in patients with non-alcoholic fatty liver disease (NAFLD). MATERIALS AND METHODS: The present study was a prospective cross-sectional research of 121 patients with metabolic syndrome and evidence of hepatic steatosis on ultrasound, who underwent a 3 T MRI examination. All patients were studied with a multifrequency MECSE sequence. The PDFF was calculated using six peaks (MECSEp123456), three peaks (MECSEp456), and a single peak (MECSEp5) model. The two simpler fat peak models were compared to the six peaks model, which was considered the reference standard. Linearity was evaluated using linear regression while agreement was described using Bland-Altman analysis. RESULTS: The mean age was 47 (±9) years and BMI was 29.9 (±2.9) kg/m2. Steatosis distribution was 15%/31%/54% (S1/S2/S3, respectively). Compared to MECSEp123456, both models provided linear PDFF measurements (R2= 0.99 and 0.97, MECSEp456 and MECSEp5 respectively). Regression slope (0.92; p<0.001) and mean Bland-Altman bias (-1.5%; 95% limits of agreement: -3.19%, 0.22%) indicated minimal underestimation by using PDFF-MECSEp456. Nonetheless, mean differences in PDFF estimations varied from -1.5% (MECSEp456,p=0.006) to -2.2% (MECSEp5,p<0.001) when compared to full six fat frequencies model. CONCLUSION: Although simpler spectral fat MECSE analysis shows a linear relationship with the standard six peaks model, their variation in estimated PDFF values introduces a low but clinically significant bias in fat quantification and steatosis grading in NAFLD patients.

A tooth whitening and chemical abrasive protocol for the treatment of developmental enamel defects.

This clinical report describes a chemical abrasive protocol and whitening techniques to quantify modifications to the color and volume produced when eliminating white spots associated with developmental defects in enamel. Chemical (oxidative-erosive) abrasive treatment (whitening + 6.6% hydrochloric acid) resolves white spots up to a depth of 0.2 mm. At greater depths, infiltration with 16% hydrochloric acid followed by composite resin infiltration is recommended.

Predictors of complications and mortality following left colectomy with primary stapled anastomosis for cancer: results of a multicentric study with 1111 patients.

AIM: Reports detailing the morbidity-mortality after left colectomy are sparse and do not allow definitive conclusions to be drawn. We aimed to identify risk factors for anastomotic leakage, perioperative mortality and complications following left colectomy for colonic malignancies. METHOD: We undertook a STROBE-compliant analysis of left colectomies included in a national prospective online database. Forty-two variables were analysed as potential independent risk factors for anastomotic leakage, postoperative morbidity and mortality. Variables were selected using the 'least absolute shrinkage and selection operator' (LASSO) method. RESULTS: We analysed 1111 patients. Eight per cent of patients had a leakage and in 80% of them reoperation or surgical drainage was needed. A quarter of patients (24.9%) experienced at least one minor complication. Perioperative mortality was 2%, leakage being responsible for 47.6% of deaths. Obesity (OR 2.8, 95% CI 1.00-7.05, P = 0.04) and total parenteral nutrition (TPN) (OR 3.7, 95% CI 1.58-8.51, P = 0.002) were associated with increased risk of leakage, whereas female patients had a lower risk (OR 0.36, 95% CI 0.18-0.67, P = 0.002). Corticosteroids (P = 0.03) and oral anticoagulants (P = 0.01) doubled the risk of complications, which was lower with hyperlipidaemia (OR 0.3, P = 0.02). Patients on TPN had more complications (OR 4.02, 95% CI 2.03-8.07, P = 0.04) and higher mortality (OR 8.7, 95% CI 1.8-40.9, P = 0.006). Liver disease and advanced age impaired survival, corticosteroids being the strongest predictor of mortality (OR 21.5, P = 0.001). CONCLUSION: Requirement for TPN was associated with more leaks, complications and mortality. Leakage was presumably responsible for almost half of deaths. Hyperlipidaemia and female gender were associated with lower rates of complications. These findings warrant a better understanding of metabolic status on perioperative outcome after left colectomy.

Effects of exposure to pyrethroid cyfluthrin on serotonin and dopamine levels in brain regions of male rats.

The effects of cyfluthrin oral exposure (1, 5, 10 and 20mg/kg bw, 6 days) on brain region monoamine levels of male rats were examined. Cyfluthrin-treated rats (1, 5 and 10mg/kg bw, orally 6 days), had no visible injury, i.e., no clinical signs of dysfunction were observed. However, rats treated with cyfluthrin at the highest dose (20mg/kg bw, orally 6 days) showed skeletal muscle contraction in the hind limbs, slight movement incoordination without any signs of dyskinesia and tremor after 1-2h of treatment. These signs were reversible at 6h after dose. After last dose of cyfluthrin, dopamine (DA) and serotonin (5-HT) and its metabolites levels were determined in brain regions hypothalamus, midbrain, hippocampus, striatum and prefrontal cortex by HPLC. Cyfluthrin (1mg/kg bw, orally 6 days) did not affect the DA, 5-HT and metabolites levels in the brain regions studied. Cyfluthrin (5, 10 and 20mg/kg bw, orally 6 days) caused a statistically significant decrease in DA and its metabolites DOPAC and HVA levels and in 5-HT and its metabolite 5-HIAA levels in a brain region- and dose-related manner. Moreover, cyfluthrin (20mg/kg bw, orally 6 days) evoked a statistically significant increase in 5-HT turnover in striatum and midbrain, and in DA turnover in striatum and prefrontal cortex. These findings indicate that serotoninergic and dopaminergic neurotransmission is affected by exposure to cyfluthrin and may contribute to the overall spectrum of neurotoxicity caused by this pyrethroid.

Interventional radiology neck procedures. / Intervencionismo en el cuello.

Ultrasonography has become extremely useful in the evaluation of masses in the head and neck. It enables us to determine the anatomic location of the masses as well as the characteristics of the tissues that compose them, thus making it possible to orient the differential diagnosis toward inflammatory, neoplastic, congenital, traumatic, or vascular lesions, although it is necessary to use computed tomography or magnetic resonance imaging to determine the complete extension of certain lesions. The growing range of interventional procedures, mostly guided by ultrasonography, now includes biopsies, drainages, infiltrations, sclerosing treatments, and tumor ablation.

Bone mineral density and bone turnover in non-cirrhotic patients with chronic hepatitis C and sustained virological response to antiviral therapy with peginterferon-alfa and ribavirin.

UNLABELLED: Patients with chronic hepatitis C have low bone mineral density and increased bone resorption related to serum transaminase levels. Elevated serum soluble tumor necrosis factor (sTNFR-55) receptor levels may play a role in the bone mass loss in these patients. Bone mass is improved and bone turnover normalized in patients who respond to antiviral therapy with interferon and ribavirin. INTRODUCTION: Low bone mineral density (BMD) has been described in patients with chronic hepatitis C (HCV). The study objective was to evaluate the effect of antiviral therapy on BMD and bone metabolism in non-cirrhotic HCV patients with sustained virological response. METHODS: We conducted a prospective study in 36 consecutive outpatients from the general community with non-cirrhotic HCV and an early and sustained virological response to peginterferon-alfa and ribavirin therapy. Determinations of BMD (dual X-ray absorptiometry at lumbar spine and femoral neck) and biochemical measurements of bone metabolism and sTNFR-55 were made at baseline, after 24 and 48 weeks of antiviral therapy, and at 48 weeks after the end of treatment. RESULTS: Patients had a significantly reduced BMD, which significantly increased during the follow-up. Serum levels of sTNFR-55 and bone turnover markers were increased at baseline and significantly reduced at all subsequent time points. We found an inverse correlation between BMD and both serum aminotransferase levels and urine deoxypyridinoline (D-pyr) and a positive correlation between serum aminotransferases and both urine D-Pyr and serum sTNFR-55. CONCLUSIONS: Patients with chronic hepatitis C have low bone mass associated with increased bone resorption, and some relationship can be expected between serum aminotransferase levels and the degree of bone mass loss. Bone mass may be improved and bone turnover normalized in patients who respond to antiviral therapy. Elevated serum sTRFR-55 levels may play a role in the bone mass loss of these patients.

Social networks in radiology: Toward a new paradigm in medical education?

The universally accepted system for the transmission of scientific knowledge in the field of medicine has long been grounded in scientific publications. Social networks can be a useful alternative or complementary method of transmitting this knowledge. Social networks (e.g., Twitter, Instagram, Facebook, LinkedIn, YouTube, and TikTok) generate educational contents that enable quality training, despite their informality. Each of these networks has strengths and weaknesses that users should know about. These platforms are free and allow for real-time discussion. They make it easy to incorporate content and to contact experts or access sources of knowledge directly. Aware of their influence, publishers have incorporated metrics to measure the impact of their articles in social networks (Altmetrics). These networks should be incorporated into departmental training programs immediately. Nevertheless, navigating through social networks is complex, and the hashtag-based system of searching is inefficient, limiting their use in education. Despite the informality of the knowledge generated on social networks, the importance of these networks as a source of knowledge is growing. Radiology departments must design a strategy for using social networks for education rather than for propaganda, creating well-organized focal groups that search for contents through systematic, filtered review of information, digital repositories, and review sessions and for sharing this knowledge both inside and outside the department. Departments must also implement a strategy for communicating through these networks.

Highly Active W2C-Based Composites for the HER in Alkaline Solution: the Role of Surface Oxide Species.

The hydrogen evolution reaction (HER) is a crucial electrochemical process for the proposed hydrogen economy since it has the potential to provide pure hydrogen for fuel cells. Nowadays, hydrogen electroproduction is considerably expensive, so promoting the development of new non-noble catalysts for the cathode of alkaline electrolyzers appears as a suitable way to reduce the costs of this technology. In this sense, a series of tungsten-based carbide materials have been synthesized by the urea-glass route as candidates to improve the HER in alkaline media. Moreover, two different pyridinium-based ionic liquids were employed to modify the surface of the carbide grains and control the amount and nature of their surface species. The main results indicate that the catalyst surface composition is modified in the hybrid materials, which are then distinguished by the appearance of tungsten suboxide structures. This implies the action of ionic liquids as reducing agents. Consequently, differential electrochemical mass spectrometry (DEMS) is used to precisely determine the onset potentials and rate-determining steps (RDS) for the HER in alkaline media. Remarkably, the modified surfaces show high catalytic performance (overpotentials between 45 and 60 mV) and RDS changes from Heyrovsky-Volmer to Heyrovsky as the surface oxide structures get reduced. H2O molecule reduction is then faster at tungsten suboxide, which allows the formation of the adsorbed hydrogen at the surface, boosting the catalytic activity and the kinetics of the alkaline HER.

Percutaneous ablation of renal tumors: Long-term outcomes.

OBJECTIVE: To evaluate the long-term outcomes of renal tumor ablation, analyzing efficacy, long-term survival, and factors associated with complications and therapeutic success. MATERIAL AND METHODS: We retrospectively reviewed 305 ablations (generally done with expandable electrodes) of 273 renal tumors between May 2005 and April 2019. We analyzed survival, primary and secondary efficacy, and complications according to various patient factors and tumor characteristics. RESULTS: Mean blood creatinine was 1.14 mg/dL before treatment and 1.30 mg/dL after treatment (p < 0.0001). Complications were observed in 13.25% of the ablations, including major complications in in 4.97%. Complications were associated with age (p = 0.013) and tumor diameter (p < 0.0001). Primary efficacy was 96.28%. Incomplete ablation was more common in lesions measuring > 4 cm in diameter (p = 0.002). Secondary efficacy was 95.28%. The only factor associated with the risk of recurrence was the size of the tumor (p = 0.02). Overall survival was 95.26% at 1 year, 77.01% at 5 years, and 51.78% at 10 years, with no differences between patients with malignant and benign lesions. Mortality was higher in patients with creatinine >1 (p = 0.05) or ASA > 2 (p = 0.0001). CONCLUSIONS: Percutaneous ablation is extremely efficacious for renal tumors; it improves the prognosis of renal carcinoma to the point where it does not differ from that of benign lesions. Complications are rare. Like survival, complications are associated with age and overall health status.

Teleradiology: good practice guide.

Teleradiology is the electronic transmission of radiological images from one location to another with the main purpose of interpreting or consulting a diagnosis and must be subject to codes of conduct agreed upon by professional societies. The content of fourteen teleradiology best practice guidelines is analyzed. Their guiding principles are: the best interest and benefit of the patient, quality and safety standards homologous to the local radiology service, and use as a complement and support of the same. As legal obligations: guaranteeing rights by applying the principle of the patient's country of origin, establishing requirements in international teleradiology and civil liability insurance. Regarding the radiological process: integration with the local service process, guaranteeing the quality of images and reports, access to previous studies and reports and complying with the principles of radioprotection. Regarding professional requirements: compliance with the required registrations, licenses and qualifications, training and qualification of the radiologist and technician, prevention of fraudulent practices, respect for labor standards and remuneration of the radiologist. Subcontracting must be justified, managing the risk of commoditization. Compliance with the system's technical standards.

Salmonella Paratyphi B var Java infections associated with exposure to turtles in Bizkaia, Spain, September 2010 to October 2011.

Between September 2010 and October 2011, the Unit of Epidemiology in the Department of Public Health in Bizkaia, Spain identified eight cases of Salmonella Paratyphi B var Java infection and three cases of infection with its possible monophasic variant 4,5,12:b:- dT+. Six cases reported contact with turtles and S. Java was isolated from three of these turtles' habitats. The isolates from the patients and their respective turtles were indistinguishable by pulsed-field gel electrophoresis (PFGE). Although other reptiles can also carry Salmonella, turtles pose a special risk, as they are commonly kept as pets for children. This emphasizes the need to give recommendations regarding ownership and handling of aquatic turtles and other reptiles. As parents are often not aware of the risk of infection associated with the presence of turtles in the household, it would be appropriate to inform potential buyers at points of sale about the risk of infection and measures they can take to minimise this risk.

Detection of 16SrIV-A phytoplasma DNA in Colpoptera sp. (Hemiptera: Nogodinidae) insects in Yucatan Peninsula, Mexico.

Lethal yellowing (LY) is a disease that affects coconut and other palm species. It is associated to phytoplasmas of the group 16SrIV and the only reported insect vector for this pathogen so far is Haplaxius crudus. H. crudus is present in Mexico and has been associated to 16SrIV phytoplasmas, however, it was not detectable during a LY outbreak in the coast of Yucatan, Mexico, suggesting the existence of other vector species. To test this hypothesis a survey of insects was carried out and a total of 3074 insects were captured during a year of monthly sampling. Ten taxonomic orders were identified in this sample, Hemiptera being the most abundant (N=2094), and these were classified into nine families. The leafhopper Colpoptera sp. from to the Nogodinidae family was de most abundant representing 56% of the total number of insects sampled and 23% of these samples resulted positive for LY phytoplasma by PCR detection. The BLAST comparison, virtual RFLP and phylogenetic analyses of the sequenced amplicons relate the detected phytoplasma to the subgroup 16SrIV-A. The findings presented herein suggest that Colpoptera sp. could be considered as a new putative vector of the LY-causing phytoplasmas in Mexico and a candidate for further research.

Ordered transcriptional factor recruitment and epigenetic regulation of tnf-alpha in necrotizing acute pancreatitis.

Tauhe expression of the critical initiator cytokine TNF-alpha was strongly upregulated in vivo in acute necrotic pancreatitis (AP) in rodents and in vitro in TNF-alpha activated acinar AR42J cells. Upregulation of tnf-alpha, inos, icam-1 and il-6 occurred both in TNF-alpha receptor 1 and 2 knock-out mice, but not in TNF-alpha knock-out mice, in cerulein-induced acute pancreatitis. Chromatin immunoprecipitation analysis showed that transcriptional factors (ELK-1, SP1, NF-kappaB and EGR-1) and chromatin modification complexes (HDAC1, HDAC2, GCN5, PCAF and CBP) were recruited and/or released from the promoter in a strictly ordered mechanism. Activation of tnf-alpha gene was also accompanied by an ordered increased level of histone H3K9, H3K14 and H3K18-acetylation and H3K4 methylation, as well as H4K5 acetylation. A better knowledge of the molecular mechanisms that control tnf-alpha gene regulation will provide deeper understanding of the initiation and development of the inflammatory processes occurring in acute pancreatitis triggered by TNF-alpha cytokine.

[The role of tutors in training residents: future outlook]. / El papel de los tutores en la formación de los residentes. Perspectivas de futuro.

Introduced late in the Spanish system of training residents, the figure of the tutor has been detailed in the new legislation governing the training of medical specialists. The law also details the functions of tutors, some of which have been relegated to the regional governments. The functions of tutors are outlined in six sections: planning training activity, receiving new residents, proposing individual training plans, acting as a reference for residents, promoting residents' participation in educational activities and research, and participating in the evaluation of residents. The recognition of tutors' work has hardly gone beyond the recognition of their managerial functions and of their need for special training. The future publication of new regulations by the regional governments might increase this recognition. On the other hand, the development of the new core curriculum with different training trunks will probably pose new challenges and increase tutors' workload.

[Evaluating resident training in radiology]. / Evaluación de la formación MIR en radiología.

Evaluation plays a key role in both the educational process and in its results. The evaluation established in the regulations for the Spanish residency system (MIR) is a two-step process that aims to teach. These steps are: a) continuous evaluation by the tutor and specialists at the training unit and b) an annual review by the evaluating committee. The resident's handbook and evaluation sheets from the rotations are the tools used for this task. Other techniques for evaluation, such as 360-degree feedback, examinations (conventional, case-based, and/or Objective Structured Clinical Examination [OSCE]), checklists, reviewing reports, or public presentation, can also complement or enhance the official evaluation. This article aims to provide information about the evaluation process and to open new possibilities to make evaluation more objective.

Pseudomonas aeruginosa and lung function decline in patients with bronchiectasis.

OBJECTIVES: The objective of this study was to analyse lung function decline over time in bronchiectasis, along with the factors associated with it. METHODS: Spirometry was measured every year in this observational, prospective study in 849 patients from the Spanish Bronchiectasis Registry (RIBRON). The main outcome was the decline in the rate of forced expiratory volume during the first second (FEV1). To be included in this study, patients needed a baseline assessment and at least one subsequent assessment. FEV1 decline was analysed using a mixed-effects linear regression model adjusted for clinically significant variables. RESULTS: We recruited 849 bronchiectasis patients with at least two annual lung function measurements (follow-up range 1-4 years). A total of 2262 lung function tests were performed (mean 2.66 per patient, range 2-5). Mean baseline FEV1 was 1.78 L (standard deviation (SD) 0.76; 71.3% predicted). Mean age was 69.1 (SD 15.4) years; 543 (64% women. The adjusted rates of FEV1 decline were -0.98% predicted/year (95% confidence interval (CI) -2.41 to -0.69) and -31.6 (95% CI -44.4 to -18.8) mL. The annual FEV1 decline was faster in those patients with chronic bronchial infection by Pseudomonas aeruginosa (-1.37% (52.1 mL) vs -0.37% (-24.6 mL); p < 0.001), greater age, increased number of severe exacerbations in the previous year and higher baseline FEV1 value. DISCUSSION: In patients with bronchiectasis, the annual rate of FEV1 decline was -31.6 mL/year and it was faster in older patients and those with chronic bronchial infection by P. aeruginosa, increased number of previous severe exacerbations and higher baseline FEV1 value.

Endourological treatment for lumbar ureteral stones. What are the benefits of flexible ureterorenoscopy?

INTRODUCTION AND OBJECTIVES: Currently, there are no established criteria regarding treatment for lumbar ureteral stones. The objective of this work is to present our results in the endourological treatment of this pathology, analyzing the variables associated with the use of the flexible ureterorenoscope. MATERIAL AND METHODS: Retrospective review of 103 patients who underwent retrograde URS with semi-rigid or flexible ureterorenoscope. Proximal location: L2-L3. Medial location: L4-L5. Semirigid URS was the initial treatment, with conversion to flexible URS when it was required to complete the procedure. Success was defined as absence of residual fragments (6 weeks). Demographic, surgical, immediate postoperative variables, and those related to the stone, were analyzed. Their correlation with the use of the flexible ureterorenoscope was evaluated. RESULTS: Mean age: 57.2 years (SD 15.6); there were 73 men (70.9%). Stone size: 8 mm (range 4-30; IQR 4.5). Proximal location: 58 (56.3%). Previous JJ: 44.7%. Previous nephrostomy: 10.7%. Semirigid URS with conversion to flexible URS: 51 (49.5%). Impacted stones: 28.2%. Intraoperative complications: 2 (1.9%). Postoperative JJ: 84.5%. Immediate postoperative complications: 23 (22.3%) (Clavien-Dindo I-II: 91.3%). Postoperative ureteral stricture: 5.8%. Success: 88.4%. Residual fragments: 12 (11.7%). Spontaneous passage: 6 (50%). Greater performance of flexible URS in proximal ureteral stones (p = 0.001) of more than 11 mm (p = 0.02) in univariate analysis, and in proximal stones [OR 3.5; 1.5-8.1; p = 0.004] in multivariate analysis. CONCLUSIONS: Endourological treatment obtained a high success rate in our sample. Size greater than 11 mm and proximal ureteral location in univariate and multivariate analysis, respectively, behaved as predictors of flexible URS.

Endourological treatment for lumbar ureteral stones. What are the benefits of flexible ureterorenoscopy? / Tratamiento endourológico de la litiasis ureteral lumbar. ¿Qué aporta la ureterorrenoscopia flexible?

INTRODUCTION AND OBJECTIVES: Currently, there are no established criteria regarding treatment for lumbar ureteral stones. The objective of this work is to present our results in the endourological treatment of this pathology, analyzing the variables associated with the use of the flexible ureterorenoscope. MATERIAL AND METHODS: Retrospective review of 103 patients who underwent retrograde URS with semi-rigid or flexible ureterorenoscope. Proximal location: L2-L3. Medial location: L4-L5. Semirigid URS was the initial treatment, with conversion to flexible URS when it was required to complete the procedure. Success was defined as absence of residual fragments (6 weeks). Demographic, surgical, immediate postoperative variables, and those related to the stone, were analyzed. Their correlation with the use of the flexible ureterorenoscope was evaluated. RESULTS: Mean age: 57.2 years (SD 15.6); there were 73 men (70.9%). Stone size: 8mm (range 4-30; IQR 4.5). Proximal location: 58 (56.3%). Previous JJ: 44.7%. Previous nephrostomy: 10.7%. Semirigid URS with conversion to flexible URS: 51 (49.5%). Impacted stones: 28.2%. Intraoperative complications: 2 (1.9%). Postoperative JJ: 84.5%. Immediate postoperative complications: 23 (22.3%) (Clavien-Dindo I-II: 91.3%). Postoperative ureteral stricture: 5.8%. Success: 88.4%. Residual fragments: 12 (11.7%). Spontaneous passage: 6 (50%). Greater performance of flexible URS in proximal ureteral stones (P=0.001) of more than 11mm (P=0.02) in univariate analysis, and in proximal stones [OR 3.5; 1.5-8.1; P=0.004] in multivariate analysis. CONCLUSIONS: Endourological treatment obtained a high success rate in our sample. Size greater than 11mm and proximal ureteral location in univariate and multivariate analysis, respectively, behaved as predictors of flexible URS.

Spectroscopic evidence for intermediate species formed during aniline polymerization and polyaniline degradation.

Spectroscopic methods are used to investigate the formation of low molecular mass intermediates during aniline (ANI) oxidation and polyaniline (PANI) degradation. Studying ANI anodic oxidation by in situ Fourier transform infrared spectroscopy (FTIRS) it is possible to obtain, for the first time, spectroscopic evidence for ANI dimers produced by head-to-tail (4-aminodiphenylamine, 4ADA) and tail-to-tail (benzidine, BZ) coupling of ANI cation radicals. The 4ADA dimer is adsorbed on the electrode surface during polymerization, as proved by cyclic voltammetry of thin PANI films and its infrared spectrum. This method also allows, with the help of computational simulations, to assign characteristic vibration frequencies for the different oxidation states of PANI. The presence of 4ADA retained inside thin polymer layers is established too. On the other hand, FTIRS demonstrates that the electrochemically promoted degradation of PANI renders p-benzoquinone as its main product. This compound, retained inside the film, is apparent in the cyclic voltammogram in the same potential region previously observed for 4ADA dimer. Therefore, applying in situ FTIRS is possible to distinguish between different chemical species (4ADA or p-benzoquinone) which give rise to voltammetric peaks in the same potential region. Indophenol and CO(2) are also detected by FTIRS during ANI oxidation and polymer degradation. The formation of CO(2) during degradation is confirmed by differential electrochemical mass spectroscopy. To the best of our knowledge, this is the first evidence of the oxidation of a conducting polymer to CO(2) by electrochemical means. The relevance of the production of different intermediate species towards PANI fabrication and applications is discussed.