Publications by authors named "Bertrand Lacroix"

14 Publications

  • Page 1 of 1

Biodegradable double cross-linked chitosan hydrogels for drug delivery: Impact of chemistry on rheological and pharmacological performance.

Int J Biol Macromol 2020 Dec 12;165(Pt B):2205-2218. Epub 2020 Oct 12.

Departamento de Química Orgánica y Farmacéutica, Facultad de Farmacia, Universidad de Sevilla, 41012 Sevilla, Spain. Electronic address:

This study investigates the impact of dual ionic and covalent cross-links (ion-XrL and cov-XrL) on the properties of chitosan-based (CTS) hydrogels as eco-friendly drug delivery systems (DDS) for the model drug diclofenac sodium (DCNa). Citric acid and a diiodo-trehalose derivative (ITrh) were the chosen ionic and covalent cross-linker, respectively. The novel hydrogels completely disintegrated within 96 h by means of a hydrolysis process mediated by the enzyme trehalase. As far as the authors are aware, this is the first time that a trehalose derivative has been used as a covalent cross-linker in the formation of biodegradable hydrogels. The impact of CTS concentration and degree of cov-XrL on rheological parameters were examined by means of an experimental model design and marked differences were found between the materials. Hydrogels with maximum elastic properties were achieved at high CTS concentrations and high degrees of cov-XrL. DCNa-loaded formulations displayed well-controlled drug-release profiles strongly dependent on formulation composition (from 17% to 40% in 72 h). Surprisingly, higher degrees of covalent cross-linking led to a boost in drug release. The formulations presented herein provides a simple and straightforward pathway to design fully biodegradable, tailor-made controlled drug delivery systems with improved rheological properties.
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http://dx.doi.org/10.1016/j.ijbiomac.2020.10.006DOI Listing
December 2020

Platinum nanoparticles stabilized by N-heterocyclic thiones. Synthesis and catalytic activity in mono- and di-hydroboration of alkynes.

Nanoscale 2020 Mar 17;12(12):6821-6831. Epub 2020 Mar 17.

Instituto de Investigaciones Químicas (IIQ), CSIC - Universidad de Sevilla, C/Américo Vespucio 49, 41092, Seville, Spain.

N-Heterocyclic Thiones (NHT) proved to be efficient ligands for the stabilization of small platinum nanoparticles (1.3-1.7 nm), synthesized by decomposition of [Pt(dba)], under a H atmosphere, in the presence of variable sub-stoichiometric amounts of the NHT. Full characterization by means of TEM, HR-TEM, NMR, ICP, TGA and XPS have been carried out, providing information about the nature of the metal nanoparticles and the interaction of the NHT ligands to the metal surface. Importantly, DFT calculations indicate that some NHT ligands interact with the metal through the C[double bond, length as m-dash]C double bond of the imidazole fragment in addition to the sulfur atom, thus providing additional stabilization to the nanoparticles. According to XPS, TGA and ICP techniques, the surface coverage by the ligand increases by decreasing the size of the substituents on the nitrogen atom. The platinum nanoparticles have been used as catalyst in the hydroboration of alkynes. The most active system is that with a less covered surface area lacking an interaction of the ligand by means of the C[double bond, length as m-dash]C double bond. This catalyst hydroborates alkynes with excellent selectivities towards the monoborylated anti-Markovnikov product (vinyl-boronate) when one equiv. of borane is used. Very interestingly, aliphatic alkynes undergo a second hydroborylation process leading to the corresponding 1,1- and 1,2-diboroylated species with good selectivities towards the former.
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http://dx.doi.org/10.1039/d0nr00251hDOI Listing
March 2020

Current management of stage I testicular germ cell tumors in a French cancer institute. A practice analysis over the 10 past years.

Bull Cancer 2019 Dec 30;106(12):1086-1093. Epub 2019 Sep 30.

Institut de cancérologie Lucien-Newirth, Department of Medical Oncology, Saint-Priest-en-Jarez, France.

Background: Testicular Germ Cell Tumors (TGCTs) represent the most frequent malignant tumour among young male adults. Orchiectomy alone cure 80% of stage I. Standard options after orchiectomy include radiotherapy (RT), chemotherapy (CT) by 1 cycle of carboplatin AUC 7 or active surveillance (SV) for seminomatous GCTs (SGCT) and retroperitoneal lymphadenectomy (RPLND), CT by 1 or 2 cycles of Bleomycine Etoposide Cisplatine (BEP) or active surveillance for nonseminomatous GCTs (NSGCT). Adjuvant treatments decrease the relapse rate after orchiectomy with substantial toxicities without any benefit on overall survival. Recent guidelines accorded utmost importance on SV rather than adjuvants strategies. The main objective of this study was to describe our current practice over the 10 past years in regard of these recommendations.

Methods: Data of 50 patients with stage I GCT treated in our institute were collected between 2006 and 2016. Demographic and anatomopathologic data were reported. Clinical practice in our center was analyzed during two periods [2006-2011] and [2012-2016] according to the European Association of Urology Guidelines in 2011.

Results: Patient's median age was 35.3 years. The analysis of clinical practice during the last 10 years showed that in SGCT, main treatment was RT than SV and CT. This option declined over the years (89% between 2006-2010 versus 53% between 2011-2016) whereas SV was more often employed (27% between 2011-2016 versus none between 2006-2010). Surveillance was used for 64% of NSGCT.

Conclusions: In our center, RT was less used over the years for the benefit of SV which is recommended by guidelines.
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http://dx.doi.org/10.1016/j.bulcan.2019.08.012DOI Listing
December 2019

Stabilisation of gold nanoparticles by N-heterocyclic thiones.

Dalton Trans 2017 Jul;46(26):8367-8371

Instituto de Investigaciones Químicas (IIQ), CSIC and Universidad de Sevilla, Avda. Américo Vespucio 49, 41092 Sevilla, Spain.

Gold nanoparticles (Au-NPs) have been prepared using N-heterocyclic thiones (NHTs) as ligand stabilisers. These Au-NPs have been shown to be very stable, even in air, and have been characterized by a combination of several techniques (TEM, HR-TEM, STEM-HAADF, EDX, DLS, elemental analysis and H NMR). These nanoparticles are active in the catalytic reduction of nitroarenes to anilines.
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http://dx.doi.org/10.1039/c7dt01856hDOI Listing
July 2017

Manganese Dioxide Supported on Porous Biomorphic Carbons as Hybrid Materials for Energy Storage Devices.

ACS Appl Mater Interfaces 2016 Nov 7;8(45):30890-30898. Epub 2016 Nov 7.

Departamento Física de la Materia Condensada, ICMS (Universidad de Sevilla-CSIC) , Avenida Reina Mercedes S/N, 41012 Seville, Spain.

A facile and low-cost method has been employed to fabricate MnO/C hybrid materials for use as binder-free electrodes for supercapacitor applications. Biocarbon monoliths were obtained through pyrolysis of beech wood, replicating the microstructure of the cellulosic precursor, and serve as 3D porous and conductive scaffolds for the direct growth of MnO nanosheets by a solution method. Evaluation of the experimental results indicates that a homogeneous and uniform composite material made of a carbon matrix exhibiting ordered hierarchical porosity and MnO nanosheets with a layered nanocrystalline structure is obtained. The tuning of the MnO content and crystallite size via the concentration of KMnO used as impregnation solution allows to obtain composites that exhibit enhanced electrochemical behavior, achieving a capacitance of 592 F g in electrodes containing 3 wt % MnO with an excellent cyclic stability. The electrode materials were characterized before and after electrochemical testing.
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http://dx.doi.org/10.1021/acsami.6b09361DOI Listing
November 2016

Fabrication of Optical Multilayer Devices from Porous Silicon Coatings with Closed Porosity by Magnetron Sputtering.

ACS Appl Mater Interfaces 2015 Jul 16;7(25):13889-97. Epub 2015 Jun 16.

†Laboratory for Nanostructured Materials and Microstructure, Instituto de Ciencia de Materiales de Sevilla CSIC-Univ. Sevilla, Av. Américo Vespucio 49, 41092 Sevilla, Spain.

The fabrication of single-material photonic-multilayer devices is explored using a new methodology to produce porous silicon layers by magnetron sputtering. Our bottom-up methodology produces highly stable amorphous porous silicon films with a controlled refractive index using magnetron sputtering and incorporating a large amount of deposition gas inside the closed pores. The influence of the substrate bias on the formation of the closed porosity was explored here for the first time when He was used as the deposition gas. We successfully simulated, designed, and characterized Bragg reflectors and an optical microcavity that integrates these porous layers. The sharp interfaces between the dense and porous layers combined with the adequate control of the refractive index and thickness allowed for excellent agreement between the simulation and the experiments. The versatility of the magnetron sputtering technique allowed for the preparation of these structures for a wide range of substrates such as polymers while also taking advantage of the oblique angle deposition to prepare Bragg reflectors with a controlled lateral gradient in the stop band wavelengths.
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http://dx.doi.org/10.1021/acsami.5b02356DOI Listing
July 2015

STEM-EELS analysis reveals stable high-density He in nanopores of amorphous silicon coatings deposited by magnetron sputtering.

Nanotechnology 2015 Feb 28;26(7):075703. Epub 2015 Jan 28.

Instituto de Ciencia de Materiales de Sevilla, CSIC-Univ. Sevilla, Avda. Américo Vespucio 49, E-41092 Sevilla, Spain. Institut für Energie- und Klimaforschung, Grundlagen der Elektrochemie (IEK9), Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany.

A broad interest has been showed recently on the study of nanostructuring of thin films and surfaces obtained by low-energy He plasma treatments and He incorporation via magnetron sputtering. In this paper spatially resolved electron energy-loss spectroscopy in a scanning transmission electron microscope is used to locate and characterize the He state in nanoporous amorphous silicon coatings deposited by magnetron sputtering. A dedicated MATLAB program was developed to quantify the helium density inside individual pores based on the energy position shift or peak intensity of the He K-edge. A good agreement was observed between the high density (∼35-60 at nm(-3)) and pressure (0.3-1.0 GPa) values obtained in nanoscale analysis and the values derived from macroscopic measurements (the composition obtained by proton backscattering spectroscopy coupled to the macroscopic porosity estimated from ellipsometry). This work provides new insights into these novel porous coatings, providing evidence of high-density He located inside the pores and validating the methodology applied here to characterize the formation of pores filled with the helium process gas during deposition. A similar stabilization of condensed He bubbles has been previously demonstrated by high-energy He ion implantation in metals and is newly demonstrated here using a widely employed methodology, magnetron sputtering, for achieving coatings with a high density of homogeneously distributed pores and He storage capacities as high as 21 at%.
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http://dx.doi.org/10.1088/0957-4484/26/7/075703DOI Listing
February 2015

Predictive factors for ipsilateral recurrence after nephron-sparing surgery in renal cell carcinoma.

Eur Urol 2010 Jun 19;57(6):1080-6. Epub 2010 Feb 19.

Department of Urology, University Hospital, Bordeaux, France.

Background: Ipsilateral recurrence after nephron-sparing surgery (NSS) is rare, and little is known about its specific determinants.

Objective: To determine clinical or pathologic features associated with ipsilateral recurrence after NSS performed for renal cell carcinoma (RCC).

Design, Setting, And Participants: We analysed 809 NSS procedures performed at eight academic institutions for sporadic RCCs retrospectively.

Measurements: Age, gender, indication, tumour bilaterality, tumour size, tumour location, TNM stage, Fuhrman grade, histologic subtype, and presence of positive surgical margins (PSMs) were assessed as predictors for recurrence in univariate and multivariate analysis by using a Cox proportional hazards regression model.

Results And Limitations: Among 809 NSS procedures with a median follow-up of 27 (1-252) mo, 26 ipsilateral recurrences (3.2%) occurred at a median time of 27 (14.5-38.2) mo. In univariate analysis, the following variables were significantly associated with recurrence: pT3a stage (p=0.0489), imperative indication (p<0.01), tumour bilaterality (p<0.01), tumour size >4cm (p<0.01), Fuhrman grade III or IV (p=0.0185), and PSM (p<0.01). In multivariate analysis, tumour bilaterality, tumour size >4cm, and presence of PSM remained independent predictive factors for RCC ipsilateral recurrence. Hazard ratios (HR) were 6.31, 4.57, and 11.5 for tumour bilaterality, tumour size >4cm, and PSM status, respectively. The main limitations of this study included its retrospective nature and a short follow-up.

Conclusions: RCC ipsilateral recurrence risk after NSS is significantly associated with tumour size >4cm, tumour bilaterality (synchronous or asynchronous), and PSM. Careful follow-up should be advised in patients presenting with such characteristics.
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http://dx.doi.org/10.1016/j.eururo.2010.02.019DOI Listing
June 2010

[Comparison of open and laparoscopic partial nephrectomy: a French multicentre experience].

Prog Urol 2007 Feb;17(1):45-9

Service d'Urologie, Hôpital Pontchaillou, CHU Rennes France.

Objectives: To compare open (OPN) and laparoscopic (LPN) partial nephrectomy (PN) techniques in the light of a French multicentre series.

Material And Methods: Data corresponding to 741 PN (91 laparoscopic and 650 open procedures) were compared in terms of the indications, tumour diameter, operative data, complication rates and length of hospital stay.

Results: Tumours were smaller in the LPN group (2.7 vs 3.4 cm, p = 0.001). There were fewer malignant tumours (71.1% vs 80% p = 0.05) and fewer NP by necessity (20.9% vs 31.4%. p = 0.04) in the LPN group than in the OPN group. There were fewer hilar tumours in the LPN group than in the OPN group (LPN: 4% vs OPN: 14.8%, p = 0.03). Pedicle clamping was performed less frequently in the LPN group (33% vs 50.2%, p = 0.002) but for a significantly longer mean duration (35 minutes vs 19 minutes, p = 0.0001). The mean operating time was longer in the LPN group (163 vs 150 minutes, p = 0.02). The surgical complication rate (17.6% vs 14.3%), transfusion rate (6.6% vs 10.5%) and mean blood loss (363 vs 434 ml) were not significantly different between the 2 groups. There were significantly more urinary fistulas (12.1% vs 2.5%, p < 0.001) and medical complications (24.2% vs 14%, p = 0.01) in the laparoscopy group, but, in the longer-term, urinarvfistula rates were comparable in the 2 groups. The length of hospital stay was shorter for LPN (9.1 vs 11.2 days, p = 0.009).

Conclusion: This comparative series, reflecting initial experience, shows that laparoscopic partial nephrectomy achieves similar operative and perioperative results to those of open partial nephrectomy. However, the indications for laparoscopic partial nephrectomy remain selective, as the pedicle clamping time and medical complication rates are higher with laparoscopic surgery. Experience and technical progress in laparoscopic partial nephrectomy should make the operative technique comparable to that of open surgery.
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http://dx.doi.org/10.1016/s1166-7087(07)92224-1DOI Listing
February 2007

Morbidity and clinical outcome of nephron-sparing surgery in relation to tumour size and indication.

Eur Urol 2007 Jul 16;52(1):148-54. Epub 2007 Jan 16.

Department of Urology, Rennes University Hospital, Rennes, France.

Objective: To analyse through a large multicentre series, morbidity of nephron-sparing surgery (NSS) in relation to tumour size and surgical indication.

Methods: The study included patients from eight international academic centres. Age, sex, TNM stage, tumour size, Fuhrman grade, Eastern Cooperative Oncology Group performance status (ECOG-PS), surgical margins, local and distant recurrences, and overall and cancer-specific survival rates were collected and analysed. Indication for elective or mandatory NSS, medical and surgical complication rates, mean blood loss, blood transfusion, and length of hospital stay were specifically recorded for the purpose of this study. Groups were compared for qualitative and quantitative variables by using chi(2) (Fischer exact test) and Student t tests, respectively.

Results: A total of 1048 NSS procedures were included in this study. Mean tumour size was 3.4+/-2.1cm. In 730 elective procedures mean operative time (p=0.002), mean blood loss (p=0.01), the need for blood transfusion (p=0.001), and urinary fistula rate (p=0.01) were significantly increased for tumours >4 cm. However, these differences did not result in significantly increased medical (p=0.4), surgical complication rates (p=0.6), or length of hospital stay (p=0.9). Finally, in elective procedures for malignant tumours, positive surgical margins, local or distant recurrence rates, and cancer-specific survival were not significantly different in tumours < or =4 cm and >4 cm.

Conclusion: Excellent cancer control and outcomes can be achieved with NSS in carefully selected patients with tumours >4 cm. Expanding the size indication of elective NSS results in an increased but acceptable morbidity.
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http://dx.doi.org/10.1016/j.eururo.2007.01.039DOI Listing
July 2007

[Laparoscopic treatment of an isolated ureteropelvic junction disruption following blunt abdominal trauma].

Prog Urol 2006 Nov;16(5):620-2

Service d'Urologie, Hôpital Nord, Saint-Etienne, France.

Isolated disruption of the ureteropelvic junction following blunt abdominal trauma is rare, although not exceptional. The diagnosis may be delayed. CT-scan with excretory phase imaging is the usual mode of diagnosis. The urinary tract can be repaired by an ureteropyelic anastomosis over a stent. The authors report the first case of an isolated disruption of the ureteropelvic junction following blunt abdominal trauma repaired by retroperitoneal laparoscopy.
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November 2006

[Retroperitoneal laparoscopic pyeloplasty: retrospective study of 45 consecutive adult cases].

Prog Urol 2006 Sep;16(4):439-44

Service d'Urologie-Andrologie, CHU de Saint-Etienne, France.

Objective: To evaluate the results of retroperitoneal laparoscopic surgical repair of ureteropelvic junction (UPJ) syndrome.

Material And Methods: Retrospective study of 45 consecutive Küss-Anderson-Hynes laparoscopic pyeloplasties performed over a 4-year period (December 1998-November 2002) in adults (26 women, 19 men) with a mean age of 44.8 years (range: 16-83 years).

Results: The mean operating time was 138 minutes (range: 75-250 minutes). Open conversion was necessary in 3 cases: necrotic pyelitis, ectopic renal artery, posterior pelvic tear. The mean hospital stay was 6.1 days. With a mean follow-up of 19 months (range: 3-58 months), the clinical success rate was 97.6% and the success rate on IVU or scintigraphy was 83.3%.

Conclusion: This series confirms that laparoscopic pyeloplasty is a minimally invasive technique that gives better results than those of the various endopyelotomy techniques and equivalent results to those of open pyeloplasty with decreased morbidity.
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September 2006

[One-stage laparoscopic bilateral upper pole nephrectomy for ectopic insertion of complete ureteral duplication].

Prog Urol 2003 Apr;13(2):342-5

Service d'Urologie-Andrologie, Hôpital Nord, 42055 Saint Etienne.

Ectopic ureteric insertion of the superior renal unit in the context of complete ureteric duplication is frequently accompanied by destruction of the corresponding parenchymal territory. Surgical treatment must comprise upper pole nephrectomy with partial ureterectomy. The authors report a case of one-stage retroperitoneal laparoscopic bilateral treatment which could become the treatment of choice of this disease.
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April 2003

[Prognostic factors of invasive bladder cancer with lymph node invasion].

Prog Urol 2002 Sep;12(4):615-20

Service d'Urologie-Andrologie, Hôpital Nord, CHU, Saint-Etienne.

Objective: To identify the prognostic factors influencing survival and to assess the value of extensive lymphadenectomy in invasive bladder cancer with lymph node invasion.

Material And Methods: The medical records of 62 patients treated by cystectomy with curative lymphadenectomy for invasive bladder cancer with lymph node invasion were reviewed. Thirty four patients had lymph node dissection ascending at least as far as the common iliac vessels, 26 had pelvic lymph node dissection and 2 had simple lymph node biopsies.

Results: The 2-, 3- and 5-year actuarial survival rates were 37%, 26.6% and 23.6%, respectively, with a median survival of 18.4 months. This study appears to show the independent prognostic value of the following factors: tumour strictly confined to the bladder (< or = pT3a) (p = 0.002), < or = 2 invaded lymph nodes (p = 0.001), N1 lymph node stage (p = 0.009). Extensive lymphadenectomy would not provide any benefit in terms of survival compared to simple pelvic lymph node dissection (p = 0.8). Common iliac node invasion appears to be a factor of poor prognosis when the tumour extends beyond the bladder (> pT3a) (p = 0.018).

Conclusion: In these patients with invasive bladder cancer and lymph node invasion, a number of invaded lymph nodes < or = 2 and local stage < or = pT3a appear to be favourable prognostic factors resulting in a 23.6% remission rate (56.8% when both factors were present simultaneously) after cystectomy plus lymphadenectomy. Extensive lymphadenectomy including the common iliac vessels would not improve survival compared to pelvic lymph node dissection, but nevertheless appears us to be justified, as the presence of common iliac lymph node invasion constitutes a significant and powerful prognostic factor to recommend adjuvant therapy.
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September 2002