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Pascal Simon

Publications and source records attributed to Pascal Simon.

8 recordsLinked to original sources
PubMed2006

Development of a seeded scaffold in the great omentum: feasibility of an in vivo bioreactor for bladder tissue engineering.

OBJECTIVES: Tissue engineering is very promising in bladder reconstruction. However, one of the main problems is to limit the development of ischaemic fibrosis during tissue maturation. We describe a model using the omentum as an in vivo bioreactor for a previously seeded scaffold. METHODS: Bladder biopsies were taken from five female pigs, from which both urothelial and smooth muscle cells cultures were made. These cultured cells were used to seed a sphere-shaped small intestinal submucosa (SIS) matrix, which was transferred into the omentum after 3 wk of cell growth. The grafts were harvested 3 wk later and histologic, immunohistochemical, and functional studies were performed. RESULTS: We obtained a highly vascularized tissue-engineered construct that contracted in response to acetylcholine stimulation. The wall thickness was 4mm, on average. Histologic and immunostaining analysis of the construct confirmed the presence of a multilayer urothelium on the luminal aspect and deeper fascicles organised tissue composed of differentiated smooth muscle cells and mature fibroblasts without evidence of inflammation or necrosis. Large- and small-diameter vessels were clearly identified histologically in the tissue obtained. CONCLUSION: The omentum permitted in vivo maturation of seeded scaffolds with the development of a dense vascularisation that is anticipated to prevent fibrosis and loss of contractility. This in vivo maturation into the omentum could be the first step before in situ implantation of the construct.

Animals↗
PubMed2006

Quantum criticality in a double-quantum-dot system.

We discuss the realization of the quantum-critical non-Fermi-liquid state, originally discovered within the two-impurity Kondo model, in double-quantum-dot systems. Contrary to common belief, the corresponding fixed point is robust against particle-hole and various other asymmetries and is unstable only to charge transfer between the two dots. We propose an experimental setup where such charge transfer processes are suppressed, allowing a controlled approach to the quantum-critical state. We also discuss transport and scaling properties in the vicinity of the critical point.

Journal Article↗
PubMed2006

[How to anticipate specialization at the Examen National Classant (National Entrance Examination) to encourage interns to choose urology].

OBJECTIVES: To analyse the value of an introduction to urology session to recruit interns following the Examen National Classant (ENC) (National Entrance Examination). MATERIALS AND METHODS: Over a 2-year period, interns appointed to surgery in Paris participated in a one-day introduction to urology session before starting work as surgical interns. A questionnaire at the beginning of internship recorded: age, gender, teaching hospital, student attachment in urology and desired specialization as a function of the surgical training programmes proposed by the ENC. Items concerning the desired specialization were resubmitted to the interns at the end of the session. RESULTS: Population. 166 interns, 98 females (59%) and 68 males (41%) with a mean age of 24.8 +/- 5 years (range: 22-31) participated in this study. 110 interns had trained at a Parisian teaching hospital (66.2%) and 56 (33.8%) had trained at a provincial teaching hospital. 31 interns (18.7%) had completed at least one urology attachment during their medical training. Desired specialization: Orthopaedics was the discipline most frequently cited (n=48; 28.9%). Urology was selected by 19 interns (11.4%), 17 of whom had completed an urology attachment during their medical training. At the end of the introduction to urology session, another 15 interns initially oriented towards other specializations were interested in urology training. CONCLUSION: Specialization of certain surgical disciplines during internship could become inevitable in the medium term. In this case, the organization of national introduction to urology sessions in each ENC allocation region would be a solution to encourage motivated interns to immediately choose urology as their surgical speciality by preference rather than by default.

Adult↗
PubMed2005

Ruderman-Kittel-Kasuya-Yosida and magnetic-field interactions in coupled Kondo quantum dots.

We investigate theoretically the transport properties of two independent artificial Kondo impurities. They are coupled together via a tunable Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction. For strong enough antiferromagnetic RKKY interaction, the impurity density of states increases with the applied in-plane magnetic-field. This effect can be used to distinguish between antiferromagnetic and ferromagnetic RKKY interactions. These results may be relevant to explain some features of recent experiments by Craig et al. [Science 304, 565 (2004)].

Journal Article↗
PubMed2005

[Results of the AMS 800 artificial urinary sphincter in men, based on a series of 47 patients].

INTRODUCTION: Male urinary incontinence due to sphincter incompetence is usually secondary to prostate surgery. After failure of other treatments, severe sphincter incompetence requires placement of an artificial urinary sphincter The authors present the results of the AMS 800 artificial urinary sphincter based on a series of 47 consecutively operated patients. PATIENTS AND METHODS: From 1990 to 2003, 47 AMS 800 were inserted by the same operator and according to the same technique. The aetiologies of urinary incontinence were: radical prostatectomy (45% of cases), transurethral resection of the prostate (36%), open prostatectomy (10.5%), and others (8.5%). RESULTS: The mean age of the patients was 65 years. The mean follow-up was 36 months. The mean time to insertion was 3 years and 10 months (range: 5 months-15 years). 23.4% of patients presented one or several complications (mechanical failure: 19%; infection; 10.6%; erosion: 4%; bladder stones: 2%), 21% of patients required one or several surgical revisions after a mean interval of 25.5 months (range: 2-80 months). The actuarial 5-year revision rate was 25.5%. With a mean follow-up of 36 months, 98% of patients had a functioning artificial urinary sphincter and 83% still had their original artificial urinary sphincter Social continence and patient satisfaction rates were 87% and 95.7%, respectively. CONCLUSION: These results are comparable to those of similar published series. The AMS 800 is associated with high continence and patient satisfaction rates and currently remains the reference treatment for refractory sphincter incompetence in men.

Adult↗
PubMed2005

[Improvement of the recruitment of surgery interns derived from the Epreuves Nationales Classantes (National-Ranking Exam): practical solution applied to urology].

OBJECTIVES: To analyse the value of an urology initiation session proposed to young interns to improve recruitment of the discipline since the introduction of the new National-Ranking Exam (NRE). MATERIALS AND METHODS: In October 2004, the 77 interns appointed to surgery in Paris on the basis of the ENC participated in a one-day urology initiation session organized by the AFUF, at the AP-HP School of Surgery. All interns were given a questionnaire at the beginning of the session to record the following data: age, gender, teaching hospital, a student attachment in urology and desired specialization as a function of the surgical training programmes proposed by the ENC. Items concerning the desired specialization were resubmitted to the interns at the end of the session. RESULTS: Population. 77 interns, 48 females (62.3%) and 29 males (37.7%) with a mean age of 25.2 +/- 5 years (range: 23-31). 55 interns had trained at a Parisian teaching hospital (67%) and 22 (28.6%) had trained at a provincial teaching hospital. 16 interns (20.8%) had completed at least one urology attachment during their medical training. Desired specialization. Orthopaedics was the discipline most frequently cited (n = 20; 26%). Urology was chosen by 8 interns (10.40%), who had all completed an urology attachment during their medical training. At the end of the urology initiation session, another 8 interns expressed the desire to specialize in urology. Of the 16 potential urology interns, 9 (56.2%) confirmed that their decision was final. CONCLUSION: Urology occupies a special place and remains a popular surgical speciality among students. Organization of practical sessions constitutes a solution to inform, create an emulation and motivate surgery interns to choose urology.

Adult↗
PubMed2002

Finite-size effects in conductance measurements on quantum dots.

The observation of the Kondo effect in quantum dots has provided new opportunities to finally observe the controversial Kondo screening cloud. Here we study the conductance of a quantum dot embedded in a finite length quantum wire, predicting a change in behavior when the length of the wire is comparable to the size of the screening cloud.

Journal Article↗