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1.
BJU Int ; 2023 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-38093673

RESUMO

OBJECTIVES: To report oncological outcomes of active surveillance (AS) at a single non-academic institution adopting the standardised Prostate Cancer Research International Active Surveillance (PRIAS) protocol. PATIENTS AND METHODS: Competing risk analyses estimated the incidence of overall mortality, metastases, conversion to treatment, and grade reclassification. The incidence of reclassification and adverse pathological findings at radical prostatectomy were compared between patients fulfilling all PRIAS inclusion criteria vs those not fulfilling at least one. RESULTS: We analysed 341 men with Grade Group 1 prostate cancer (PCa) followed on AS between 2010 and 2022. There were no PCa deaths, two patients developed distant metastases and were alive at the end of the study period. The 10-year cumulative incidence of metastases was 1.9% (95% confidence interval [CI] 0.33-6.4%). A total of 111 men were reclassified, and 127 underwent definitive treatment. Men not fulfilling at least one PRIAS inclusion criteria (n = 43) had a higher incidence of reclassification (subdistribution hazards ratio 1.73, 95% CI 1.07-2.81; P = 0.03), but similar rates of adverse pathological findings at radical prostatectomy. CONCLUSION: Metastases in men on AS at a non-academic institution are as rare as those reported in established international cohorts. Men followed without stringent inclusion criteria should be counselled about the higher incidence of reclassification and reassured they can expect rates of adverse pathological findings comparable to those fulfilling all criteria. Therefore, AS should be proposed to all men with low-grade PCa regardless of whether they are followed at academic institutions or smaller community hospitals.

2.
World J Urol ; 40(4): 1005-1010, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34999905

RESUMO

PURPOSE: There is currently no consensus regarding the optimal treatment strategy for patients presenting with synchronous bilateral renal masses. The decision to perform bilateral procedures on the same intervention or in staged procedures is debated. The aim of this manuscript is to analyse the outcomes of simultaneous robot-assisted partial nephrectomy (RAPN) in a series of patients with bilateral renal masses treated at five Italian robotic institutions. METHODS: Data from a prospectively maintained multi-institutional database on patients subjected to simultaneous RAPN between November 2011 and July 2019 were reviewed. RAPNs were performed with da Vinci Si or Xi surgical system by expert robotic surgeons. Baseline demographics and clinical features, peri- and post-operative data were collected. RESULTS: Overall, 27 patients underwent simultaneous bilateral RAPN, and 54 RAPNs were performed without need of conversion; median operative time was 250 minutes, median estimated blood loss was 200 mL. Renal artery clamping was needed for 27 (50%) RAPNs with a median warm ischemia time of 15 minutes and no case of acute kidney injury. Complications were reported in 7 (25.9%) patients, mainly represented by Clavien 2 events (6 blood transfusions). Positive surgical margins were assessed in 2 (3.7%) of the renal cell carcinoma. At the median follow-up of 30 months, recurrence-free survival was 100%. CONCLUSION: Our data showed that, in selected patients and expert hands, simultaneous bilateral RAPNs could be a safe and feasible procedure with promising results for the treatment of bilateral synchronous renal masses.


Assuntos
Neoplasias Renais , Procedimentos Cirúrgicos Robóticos , Robótica , Humanos , Neoplasias Renais/patologia , Neoplasias Renais/cirurgia , Nefrectomia/métodos , Estudos Retrospectivos , Procedimentos Cirúrgicos Robóticos/métodos , Robótica/métodos , Resultado do Tratamento
3.
Neuroinformatics ; 20(4): 1121-1136, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35792992

RESUMO

Neuronal networks are regulated by three-dimensional spatial and structural properties. Despite robust evidence of functional implications in the modulation of cognition, little is known about the three-dimensional internal organization of cholinergic networks in the forebrain. Cholinergic networks in the forebrain primarily occur in subcortical nuclei, specifically the septum, nucleus basalis, globus pallidus, nucleus accumbens, and the caudate-putamen. Therefore, the present investigation analyzed the three-dimensional spatial organization of 14,000 cholinergic neurons that expressed choline acetyltransferase (ChAT) in these subcortical nuclei of the mouse forebrain. Point process theory and graph signal processing techniques identified three topological principles of organization. First, cholinergic interneuronal distance is not uniform across brain regions. Specifically, in the septum, globus pallidus, nucleus accumbens, and the caudate-putamen, the cholinergic neurons were clustered compared with a uniform random distribution. In contrast, in the nucleus basalis, the cholinergic neurons had a spatial distribution of greater regularity than a uniform random distribution. Second, a quarter of the caudate-putamen is composed of axonal bundles, yet the spatial distribution of cholinergic neurons remained clustered when axonal bundles were accounted for. However, comparison with an inhomogeneous Poisson distribution showed that the nucleus basalis and caudate-putamen findings could be explained by density gradients in those structures. Third, the number of cholinergic neurons varies as a function of the volume of a specific brain region but cell body volume is constant across regions. The results of the present investigation provide topographic descriptions of cholinergic somata distribution and axonal conduits, and demonstrate spatial differences in cognitive control networks. The study provides a comprehensive digital database of the total population of ChAT-positive neurons in the reported structures, with the x,y,z coordinates of each neuron at micrometer resolution. This information is important for future digital cellular atlases and computational models of the forebrain cholinergic system enabling models based on actual spatial geometry.


Assuntos
Colina O-Acetiltransferase , Globo Pálido , Animais , Camundongos , Colina O-Acetiltransferase/análise , Colina O-Acetiltransferase/metabolismo , Globo Pálido/química , Globo Pálido/metabolismo , Núcleo Accumbens/química , Núcleo Accumbens/metabolismo , Putamen/química , Putamen/metabolismo , Prosencéfalo/química , Prosencéfalo/metabolismo , Neurônios Colinérgicos/química , Neurônios Colinérgicos/metabolismo , Colinérgicos/análise , Análise Espacial
4.
Methods Mol Biol ; 2431: 271-288, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35412282

RESUMO

Transport of cargoes along axons is crucial for ensuring effective neuronal function and survival. Lysosomes, which are membrane-bound organelles responsible for the degradation of macromolecules, are among the many cargoes being transported. Compartmentalized systems that allow for the separation of the somatic compartment from the axonal network, are widely used in the field of neurobiology and in the study of axonal transport in particular. Among the various solutions available, microfluidics chambers that take advantage of fluidic separation between different compartments, have seen widespread adoption. Said chambers are made of polydimethylsiloxane (PDMS), a transparent, gas permeable compound, which is compatible with fluorescence microscopy, and have significantly positively impacted cellular neuroscience, drastically increasing our understanding of axonal peripheral signaling. Here we describe a two-layered microfluidics chamber, engineered to allow for the culture of adult sensory neurons. This device was designed to promote the proper placement of adult sensory neurons in the somatic chamber in proximity of the microgrooves. We detail the production of the master mold, how to fabricate and assemble the device and how to disaggregate and load the cells in it. In addition, we provide details on how to conduct and analyze an axonal transport experiment using a custom made script in MATLAB designed by our laboratory.


Assuntos
Transporte Axonal , Microfluídica , Transporte Axonal/fisiologia , Axônios/metabolismo , Microfluídica/métodos , Organelas/metabolismo , Células Receptoras Sensoriais
5.
Macromol Biosci ; 22(12): e2200315, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36114714

RESUMO

Due to the severity of peripheral nerve injuries (PNI) and spinal cord injuries (SCI), treatment options for patients are limited. In this context, biomaterials designed to promote regeneration and reinstate the lost function are being explored. Such biomaterials should be able to mimic the biological, chemical, and physical cues of the extracellular matrix for maximum effectiveness as therapeutic agents. Development of biomaterials with desirable physical, chemical, and electrical properties, however, has proven challenging. Here a novel biomaterial formulation achieved by blending the pigment melanin and the natural polymer Poly-3-hydroxybutyrate (PHB) is proposed. Physio-chemical measurements of electrospun fibers reveal a feature rich surface nano-topography, a semiconducting-nature, and brain-tissue-like poroviscoelastic properties. Resulting fibers improve cell adhesion and growth of mouse sensory and motor neurons, without any observable toxicity. Further, the presence of polar functional groups positively affect the kinetics of fibers degradation at a pH (≈7.4) comparable to that of body fluids. Thus, melanin-PHB blended scaffolds are found to be physio-chemically, electrically, and biologically compatible with neural tissues and could be used as a regenerative modality for neural tissue injuries. A biomaterial for scaffolds intended to promote regeneration of nerve tissue after injury is developed. This biomaterial, obtained by mixing the pigment melanin and the natural polymer PHB, is biodegradable, electrically conductive, and beneficial to the growth of motor and sensory neurons. Thus, it is believed that this biomaterial can be used in the context of healthcare applications.


Assuntos
Tecido Nervoso , Engenharia Tecidual , Camundongos , Animais , Engenharia Tecidual/métodos , Alicerces Teciduais/química , Melaninas/farmacologia , Ácido 3-Hidroxibutírico/farmacologia , Materiais Biocompatíveis/farmacologia , Materiais Biocompatíveis/química , Poliésteres/farmacologia , Poliésteres/química , Hidroxibutiratos/farmacologia , Polímeros/química
6.
Asian J Urol ; 9(3): 272-281, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36035338

RESUMO

Objective: To report the outcomes of surgery for a contemporary series of patients with locally advanced non-metastatic renal cell carcinoma (RCC) treated at a referral academic centre, focusing on technical nuances and on the value of a multidisciplinary team. Methods: We queried our prospective institutional database to identify patients undergoing surgical treatment for locally advanced (cT3-T4 N0-1 M0) renal masses suspected of RCC at our centre between January 2017 and December 2020. Results: Overall, 32 patients were included in the analytic cohort. Of these, 12 (37.5%) tumours were staged as cT3a, 8 (25.0%) as cT3b, 5 (15.6%) as cT3c, and 7 (21.9%) as cT4; 6 (18.8%) patients had preoperative evidence of lymph node involvement. Nine (28.1%) patients underwent nephron-sparing surgery while 23 (71.9%) received radical nephrectomy. A template-based lymphadenectomy was performed in 12 cases, with evidence of disease in 3 (25.0%) at definitive histopathological analysis. Four cases of RCC with level IV inferior vena cava thrombosis were successfully treated using liver transplant techniques without the need for extracorporeal circulation. While intraoperative complications were recorded in 3 (9.4%) patients, no postoperative major complications (Clavien-Dindo ≥3) were observed. At histopathological analysis, 2 (6.2%) patients who underwent partial nephrectomy harboured oncocytoma, while the most common malignant histotype was clear cell RCC (62.5%), with a median Leibovich score of 6 (interquartile range 5-7). Conclusion: Locally advanced RCC is a complex and heterogenous disease posing several challenges to surgical teams. Our experience confirms that provided careful patient selection, surgery in experienced hands can achieve favourable perioperative, oncological, and functional outcomes.

7.
Front Surg ; 8: 665328, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34136528

RESUMO

Objective: To report a case of robot-assisted partial nephrectomy (RAPN) for two highly complex renal tumors in a patient with a Horseshoe kidney (HSK), focusing on the utility of hyperaccuracy three-dimensional (HA3D) virtual models for accurate preoperative and intraoperative planning of the procedure. Methods: A 74-year-old Caucasian male patient was referred to our Unit for incidental detection of two complex renal masses in the left portion of a HSK. The 50 × 55 mm, larger, predominantly exophytic renal mass was located at the middle-lower pole of the left-sided kidney (PADUA score 9). The 16 × 17 mm, smaller, hilar renal mass was located at the middle-higher pole of the left-sided kidney (PADUA score 9). Contrast-enhanced CT scan images in DICOM format were processed using a dedicated software to achieve a HA3D virtual reconstructions. RAPN was performed by a highly experienced surgeon using the da Vinci Si robotic platform with a three-arm configuration. A selective delayed clamping strategy was adopted for resection of the larger renal mass while a clampless strategy was adopted for the smaller renal mass. An enucleative resection strategy was pursued for both tumors. Results: The overall operative time was 150 min, with a warm ischemia time of 21 min. No intraoperative or postoperative complications were recorded. Final resection technique according to the SIB score was pure enucleation for both masses. At histopathological analysis, both renal masses were clear cell renal cell carcinoma (ccRCC) (stage pT1bNxMx and pT3aNxMx for the larger and smaller mass, respectively). At a follow-up of 7 months, there was no evidence of local or systemic recurrence. Conclusions: Surgical management of complex renal masses in patients with HSKs is challenging and decision-making is highly nuanced. To optimize postoperative outcomes, proper surgical experience and careful preoperative planning are key. In this regard, 3D models can play a crucial role to refine patient counseling, surgical decision-making, and pre- and intraoperative planning during RAPN, tailoring surgical strategies and techniques according to the single patient's anatomy.

8.
Front Surg ; 8: 769527, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35004836

RESUMO

Introduction: Laparoscopic surgery for Upper Urinary Tract Urothelial Cell Carcinoma (UTUC) is still debated for its possible seeding risk and thus consequent oncological recurrences, especially for atypical ones. The aim of the study is to compare recurrence and survival after Laparoscopic vs. Open Radical Nephroureterectomy (RNU) for Upper Urinary Tract Urothelial Cancer (UTUC). Method: A retrospective evaluation of UTUC consecutive surgeries from 2008 to 2019 was conducted, including pT ≥ 2, High Grade UTUC who underwent RNU with bladder cuff excision without concomitant lymphadenectomy in three urological tertiary centers. Statistical analyses compared recurrence and cancer specific survival, based on surgical approach, while logistic multivariate analyses and Kaplan Meyer survival curve analyzed possible risk factors for recurrence and survival. Results: One hundred seven cases of RNU, 47 (43.9%) laparoscopic and 60 (56.1%) open, were included in this report. Preoperative characteristics were comparable between groups. However, tumor stage was higher in the Open arm [T3-T4 in 44 (73.3%) vs. 20 (43.4%) in Laparoscopic]. Mean follow-up was 91.6 months in laparoscopy RNU vs. 93.5 months in open RNU. Recurrence rate (RR) was comparable between groups (p = 0.594), and so was the site, although 3 (6.3%) peritoneal recurrences were found only in laparoscopic group (p = 0.057). At multivariate logistic regression, tumor stage and surgical approach were independent predictors of recurrence (p < 0.05), while only tumor stage was predictor of cancer specific death (p = 0.029). Conclusion: Surgical approach has no impact on recurrence site, overall survival, and RR. Still, according to our data peritoneal carcinomatosis was present only in laparoscopic arm, despite how it didn't reach statistical significance.

9.
Med Oncol ; 37(9): 81, 2020 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-32767163

RESUMO

First-line treatment for metastatic clear-cell renal cell carcinoma patients with intermediate and poor-risk features consists of a combination of immune checkpoint inhibitors (e.g., nivolumab + ipilimumab) or immunotherapy with an anti-vascular endothelial growth factor receptor (VEGFR) drug (e.g., axitinib). The subsequent line of therapy should be determined on the basis of previous treatments and approved drugs available, based on the results of randomized clinical trials. Unfortunately, no phase 3 trial has compared the safety and efficacy of drugs after immunotherapy; thus, drug choice is more empirical than evidence-based. As the tumor may still be anti-VEGFR drug-naïve, a tyrosine kinase inhibitor approved for first line treatment (e.g., sunitinib or pazopanib) may be beneficial. Because this is a second-line treatment, patients could also receive axitinib, cabozantinib, or a combination of lenvatinib and everolimus. The treating physician should choose an appropriate treatment according to the patient's age, comorbidities, and tolerability of previous checkpoint inhibitors, among other considerations. Cases of patients with renal cell carcinoma refractory to checkpoint inhibitor treatment are growing, warranting a review of the activity and safety of target therapies after immunotherapy.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Biomarcadores Tumorais/genética , Carcinoma de Células Renais/terapia , Imunoterapia/métodos , Neoplasias Renais/terapia , Terapia de Alvo Molecular/métodos , Anilidas/administração & dosagem , Axitinibe/administração & dosagem , Biomarcadores Tumorais/metabolismo , Carcinoma de Células Renais/imunologia , Carcinoma de Células Renais/patologia , Ensaios Clínicos como Assunto , Humanos , Indazóis , Neoplasias Renais/imunologia , Neoplasias Renais/patologia , Metástase Neoplásica , Nivolumabe/administração & dosagem , Seleção de Pacientes , Compostos de Fenilureia/administração & dosagem , Piridinas/administração & dosagem , Pirimidinas/administração & dosagem , Quinolinas/administração & dosagem , Sulfonamidas/administração & dosagem , Sunitinibe/administração & dosagem
10.
J Comp Neurol ; 528(5): 787-804, 2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-31625606

RESUMO

Recent developments in genetic engineering have established murine models that permit the selective control of cholinergic neurons via optical stimulation. Despite copious benefits granted by these experimental advances, the sensory physiognomy of these organisms has remained poorly understood. Therefore, the present study evaluates sensory and neuronal response properties of animal models developed for the study of optically induced acetylcholine release regulation. Auditory brainstem responses, fluorescence imaging, and patch clamp recording techniques were used to assess the impact of viral infection, sex, age, and anesthetic agents across the ascending auditory pathway of ChAT-Cre and ChAT-ChR2(Ai32) mice. Data analyses revealed that neither genetic configuration nor adeno-associated viral infection alters the early stages of auditory processing or the cellular response properties of cholinergic neurons. However, anesthetic agent and dosage amount profoundly modulate the response properties of brainstem neurons. Last, analyses of age-related hearing loss in virally infected ChAT-Cre mice did not differ from those reported in wild type animals. This investigation demonstrates that ChAT-Cre and ChAT-ChR2(Ai32) mice are viable models for the study of cholinergic modulation in auditory processing, and it emphasizes the need for prudence in the selection of anesthetic procedures.


Assuntos
Anestésicos/farmacologia , Neurônios Colinérgicos , Potenciais Evocados Auditivos do Tronco Encefálico/efeitos dos fármacos , Modelos Animais , Opsinas/metabolismo , Animais , Neurônios Colinérgicos/efeitos dos fármacos , Neurônios Colinérgicos/metabolismo , Corpo Estriado/efeitos dos fármacos , Corpo Estriado/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos
11.
Minerva Urol Nefrol ; 72(4): 490-497, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31833727

RESUMO

BACKGROUND: The aim of this study was to assess the early and mid-term functional outcomes of Endoscopic Robot Assisted Simple Enucleation (ERASE) verified through a standardized tumor-resection reporting system (Surface Intermediate Base [SIB] score) and to investigate for predictors of renal function (RF) loss in patients with T1 renal tumors treated in a tertiary referral institution. METHODS: Data of 553 patients treated with ERASE were analyzed. Only patients with SIB score of 0-1 and negative oncological follow-up were included. A ≥25% drop from baseline of estimated glomerular filtration rate (eGFR) was considered as a clinically meaningful functional loss. Multivariable regression models tested the relation between clinical features and RF loss at postoperative day (POD) 3 and at last follow-up. RESULTS: Overall, 347 patients with SIB 0-1 entered the study. A RF drop ≥25% was observed in 178 (37%) patients in POD 3 and in 91 (18.9%) patients at a median follow-up of 36 months, respectively. At multivariable analysis, age at surgery and PADUA score were significant predictive factors of clinically significant RF loss at POD 3, while age at surgery, female gender, higher BMI, Charlson Comorbidity Index (CCI) and preoperative eGFR were significant predictors of RF loss at last follow-up. CONCLUSIONS: Age at surgery and higher PADUA score are significant predictors of early postoperative RF loss after ERASE for T1 renal tumors, while age at surgery, female gender, higher BMI, CCI and baseline RF significantly affect mid-term RF. Larger studies and a longer follow-up are needed to confirm these results.


Assuntos
Endoscopia/métodos , Neoplasias Renais/cirurgia , Complicações Pós-Operatórias/diagnóstico , Procedimentos Cirúrgicos Robóticos/métodos , Procedimentos Cirúrgicos Urológicos/métodos , Fatores Etários , Idoso , Índice de Massa Corporal , Comorbidade , Feminino , Seguimentos , Taxa de Filtração Glomerular , Humanos , Testes de Função Renal , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Retrospectivos , Fatores Sexuais , Centros de Atenção Terciária , Resultado do Tratamento
12.
Front Surg ; 7: 588215, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33521044

RESUMO

Objective: To provide a step-by-step overview of the University of Florence technique for robotic living donor nephrectomy (LDN), focusing on its technical nuances and perioperative outcomes. Methods: A dedicated robotic LDN program at our Institution was codified in 2012. Data from patients undergoing robotic LDN from 2012 to 2019 were prospectively collected. All robotic LDNs were performed by a highly experienced surgeon, using the da Vinci Si robotic platform in a three-arm configuration. In this report we provide a detailed overview of our surgical technique for robotic LDN. The main objective of the study was to evaluate the technical feasibility and safety of the technique, including perioperative surgical complications rate and mid-term functional outcomes. Results: Overall, 36 patients undergoing robotic LDNs were included in the study. Of these, 28 (78%) were left LDNs. Median (IQR) donor pre-operative eGFR was 88 (75.6-90) ml/min/1.73 m2. In all cases, robotic LDN was completed without need of conversion. The median (IQR) overall operative time was 230 (195-258) min, while the median console time was 133 (IQR 117-166) min. The median (IQR) warm ischemia time was 175 (140-255) s. No intraoperative adverse events or 90-d major surgical complications were recorded. At a median (IQR) follow-up of 24 months (IQR 11-46), median (IQR) eGFR patients undergoing in living donor nephrectomy was 57.4 (47.9; 63.9) ml/min/1.73 m2. Conclusions: In our experience, robotic LDN is technically feasible and safe. The use of robotic surgery for LDN may provide distinct advantages for surgeons while ensuring optimal donors' perioperative and functional outcomes.

13.
Front Surg ; 7: 583798, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33262999

RESUMO

Objective: To report the University of Florence technique for robot-assisted kidney transplantation (RAKT) from living donor (LD) and deceased donor (DD), highlighting the evolution of surgical indications and technical nuances in light of a single surgeon's learning curve. Materials and Methods: A dedicated program for RAKT from LDs was developed at our Institution in 2017 and implemented later with a specific framework for DDs. All RAKTs were performed by a single highly experienced surgeon. Data from patients undergoing RAKT between January 2017 and December 2019 were prospectively collected in a dedicated web-based data platform. In this report we provide a comprehensive step-by-step overview of our technique for RAKT, focusing on the potential differences in peri-operative and mid-term functional outcomes between LDs vs. DDs. Results: Overall, 160 KTs were performed in our center during the study period. Of these, 39 (24%) were performed with a robot-assisted laparoscopic technique, both from LDs (n = 18/39 [46%]) and from DDs (n = 21/39 [54%]). Eleven (11/39 [18%]), 13(13/39 [26%]), and 15 (15/39 [30%]) RAKTs were performed in 2017, 2018, and 2019, respectively, highlighting an increasing adoption of robotics for KT over time at our Institution. Median time for arterial (19 min for LD and 18 min for DD groups), venous (21 min for LD, 20 min for DD) and uretero-vesical (18 min for LD and 15 for DD) anastomosis were comparable between the two groups (all p > 0.05), as the median rewarming time (59 min vs. 56 min, p = 0.4). The rate of postoperative surgical complications according to Clavien-Dindo classification did not differ between the two study groups, except for Clavien-Dindo grade II complications (higher among patients undergoing RAKT from DDs, 76 vs. 44%, p = 0.042). Overall, 7/39 (18%) patients (all recipients from DDs) experienced DGF; two of them were on dialysis at last FU. Conclusions: Our experience confirms the feasibility, safety, and favorable mid-term outcomes of RAKT from both LDs and DDs in appropriately selected recipients, highlighting the opportunity to tailor the technique to specific recipient- and/or graft-characteristics. Further research is needed to refine the technique for RAKT and to evaluate the benefits and harms of robotics for kidney transplantation from DDs.

14.
Phys Chem Chem Phys ; 11(41): 9351-63, 2009 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-19830317

RESUMO

Radicals and radical anions such as OH, NO(3) and SO(4)(-) can act as important oxidants in aqueous solutions, e.g. as a part of the tropospheric multiphase system. In the present study the aqueous phase kinetics of OH, NO(3) and SO(4)(-) radical reactions with the following ten aliphatic poly-alcohols 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2,3-propanetriol, 1,2-butanediol, 1,4-butanediol, 1,5-pentanediol, (2R,3S)-butane-1,2,3,4-tetraol (meso-erythritol), (2R,4R)-pentane-1,2,3,4,5-pentol (arabitol) and (2R,3R,4R,5R)-hexane-1,2,3,4,5,6-hexol (mannitol) were investigated. These alcohols are both of anthropogenic and of biogenic origin and all are highly water soluble. All rate constants throughout this study were determined as a function of the temperature between 278 < or = T [K] < or = 328. OH radical reactions with poly-alcohols (k(2nd) = 1.6-4.7 x 10(9) L mol(-1) s(-1)) are the fastest among the three investigated radicals. The corresponding NO(3) radical (k(2nd) = 0.66-1.5 x 10(7) L mol(-1) s(-1)) and SO(4)(-) radical (k(2nd) = 2.7-5.3 x 10(7) L mol(-1) s(-1)) reactions are on average two orders of magnitude slower. All three radicals react by an H-abstraction mechanism preferably at the alpha-carbon atom of the investigated alcohols. Kinetic measurements were performed using laser flash photolysis-long path absorption (LFP-LPA). Rate constants were measured either directly following the NO(3) and SO(4)(-) concentration-time profile or by a competition kinetics method using a well characterized reference reaction (SCN(-)) for OH radicals. Furthermore, obtained kinetic data are used to extend existing reactivity correlations for H-abstraction reactions with bond dissociation energies in aqueous solution and to calculate the tropospheric lifetimes of the alcohols.

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