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Biomedical subjects

D Chopin

Publications and source records attributed to D Chopin.

At least 19 recordsLinked to original sources

Laparoscopic radical nephrectomy for T1 renal cancer: the gold standard? A comparison of laparoscopic vs open nephrectomy.

OBJECTIVE: To evaluate the complication rate and clinical follow-up of patients treated for T1 renal cancer by open or laparoscopic nephrectomy at the same institution, as this approach appears to be attractive for treating small renal cancers. PATIENTS AND METHODS: Between 1995 and 2002, 39 patients underwent retroperitoneal laparoscopic and 26 transperitoneal open radical nephrectomy for T1 renal cancer (TNM 1997). Variables before during and after surgery, e.g. cancer recurrence, were compared between the groups. RESULTS: There were no differences between the laparoscopic and open groups in age, sex ratio, weight, height, fitness score, operative duration (134 vs 133 min), minor or major complications, tumour diameter, Fuhrman grade or length of follow-up. Patients who underwent laparoscopic surgery had less blood loss (133 vs 357 mL, P < 0.001), less need for transfusion (none vs 150 mL, P = 0.04), a lower consumption of analgesia drugs, and shorter hospitalization (5.5 vs 8.8 days, P < 0.001). With a mean follow-up of 20.4 months there was no recurrence or tumour progression. CONCLUSION: Laparoscopic radical nephrectomy for patients with T1 renal cancer is a safe, reliable procedure that decreases hospitalization time and bleeding, and ensures the same cancer control as open nephrectomy.

Adult↗

Cell cycle checkpoint status in human malignant mesothelioma cell lines: response to gamma radiation.

Knowledge of the function of the cell cycle checkpoints in tumour cells may be important to develop treatment strategies for human cancers. The protein p53 is an important factor that regulates cell cycle progression and apoptosis in response to drugs. In human malignant mesothelioma, p53 is generally not mutated, but may be inactivated by SV40 early region T antigen (SV40 Tag). However, the function of p53 has not been investigated in mesothelioma cells. Here, we investigated the function of the cell cycle checkpoints in six human mesothelioma cell lines (HMCLs) by studying the cell distribution in the different phases of the cell cycle by flow cytometry, and expression of cell cycle proteins, p53, p21(WAF1/CIP1) and p27(KIP1). In addition, we studied p53 gene mutations and expression of SV40 Tag. After exposure to gamma-radiation, HMCLs were arrested either in one or both phases of the cell cycle, demonstrating a heterogeneity in cell cycle control. G1 arrest was p21(WAF1/CIP1)- and p53-dependent. Lack of arrest in G1 was not related to p53 mutation or binding to SV40 Tag, except in one HMCL presenting a missense mutation at codon 248. These results may help us to understand mesothelioma and develop new treatments.

Cell Cycle↗

Outcome and complications of radical prostatectomy in patients with PSA <10 ng/ml: comparison between the retropubic, perineal and laparoscopic approach.

The objective of this work was to evaluate the oncological outcomes and complications of prostate cancer patients with prostate specific antigen (PSA)<10 ng/ml after radical prostatectomy by retropubic, perineal and laparoscopic approach. From 1988 to 2001, 306 patients with PSA<10 ng/ml underwent radical prostatectomy by the retropubic, perineal or laparoscopic approach. Mean operative time, complication rates, length of hospital stay, catheterization time and pathological results were reviewed. Kaplan-Meier analysis was used to evaluate the likelihood of biochemical PSA recurrence. There were no statistical differences between the three groups in terms of preoperative characteristics except for PSA levels (5.5, 6.5 and 6.6 ng/ml for the retropubic, perineal, and laparoscopic approach, respectively, P<0.05) and for the T1c stage prevalence (50%, 43.1% and 68.4%, P<0.05). Operating time was significatively longer in the laparoscopic approach (266 min), whereas transfusion rate (22.1%), bladder catetherization (12.1 days), and length of hospital stay (12.1 days) were higher in the retropubic group (P<0.05). The percentage of medical and surgical complications were 6.9%, 3.1% and 3.4% (P<0.05) and 18.6%, 16.9% and 11.6% (P<0.05) for the retropubic, perineal, and laparoscopic approach, respectively. Pathological staging revealed pT2 in 76.7%, 78.4% and 81.3% for retropubic, perineal and laparoscopic approach, respectively (P<0.05). Positive surgical positive margins were noted in 20.9%, 18.4% and 20.6% (P>0.05). The actuarial 3-year recurrence-free survival rate was 89.3%, 89.2% and 86.2% (P>0.05) for retropubic, perineal and laparoscopic approach, respectively. It can be concluded that in patients with preoperative PSA<10 ng/ml, clinical outcome and complication rates were similar, regardless of the choice of surgical approach.

Adenocarcinoma↗

Biomechanical simulation of Colorado instrumentation of the scoliotic spine: a preliminary study.

Few biomechanical models of the scoliotic spine were developed to simulate the Cotrel-Dubousset instrumentation, although none was dedicated to the Colorado system. The objective of this study is to adapt and assess an existing biomechanical model to simulate the effect of the Colorado instrumentation of the scoliotic spine as a function of pre-operative geometry and surgical planning. Fifteen scoliotic patients operated with a Colorado system were analysed using a knowledge extraction technique to simplify surgical procedure and to establish the biomechanical model (boundary conditions, simulation procedures,...). Preliminary results on one patient show that the Colorado surgical technique can be adequately modelled using the preoperative geometric data and limited simulation strategy parameters.

Biomechanical Phenomena↗

Spinal surgery procedure discretization.

In the last decades, scientists developed analytic models of spinal surgery to assess surgical choices and instrumentation parameters. They noted the difficulty to represent the boundary conditions on their deterministic models and recognize the lack of knowledge in surgical procedures. This paper presents a formalization technique applied to spinal surgery to improve the formulation of biomechanical models. This technique consisted into two steps: knowledge extraction and knowledge representation. The protocol was established with an expert surgeon using Colorado2 instrumentation. Surgeon's knowledge acquisition has permitted to define eleven detailed independent data cards for the different steps of surgery like hook or screw insertion, rod installation, etc... The behaviour of the concerned elements on its neighbouring entity were specified using three matrices. The link between surgery and modelling becomes easier and permits to better define the boundary conditions on each entity during the simulation.

Artificial Intelligence↗

Anatomical basis of lumboscopy.

Lumboscopy provides an approach to the retroperitoneum for the majority of upper urinary tract operations. The technique involves a knowledge of specific anatomical landmarks that differ from those in classical open surgery, because of the inferior approach to the renal pedicle with the kidney initially mobilized in a ventral and cranial position. An anatomical study was conducted on five cadavers, using images from surgical operations, in order to describe the vascular elements of the retroperitoneal spaces as they are approached during lumboscopy, as well as to define specific anatomical landmarks. Identification of psoas major is crucial as it is then possible to locate the renal pedicle opposite and the area of the great vessels medially. During dissection of the renal pedicle the renal vein and its branches are the first elements to be approached. On the left side the distal portion of the renal vein can be confused with a reno-hemi-azygo-lumbar trunk, due to the initial ventral mobilization of the kidney stretching it. Because of the inferior view of the renal pedicle the reno-hemi-azygo-lumbar trunk can obscure part of the renal artery and may be confused with the renal vein. On the right side initial identification of the inferior vena cava on the medial aspect of psoas major facilitates identification of the gonadal, renal and suprarenal veins all located in the same plane.

Cadaver↗

Correlation between sagittal plane changes and adjacent segment degeneration following lumbar spine fusion.

Adjacent segment degeneration following lumbar spine fusion remains a widely acknowledged problem, but there is insufficient knowledge regarding the factors that contribute to its occurrence. The aim of this study is to analyse the relationship between abnormal sagittal plane configuration of the lumbar spine and the development of adjacent segment degeneration. Eighty-three consecutive patients who underwent lumbar fusion for degenerative disc disease were reviewed retrospectively. Patients with spondylolytic spondylolisthesis and degenerative scoliosis were not included in this study. Mean follow-up period was 5 years. Results were analysed to determine the association between abnormal sagittal configuration and post operative adjacent segment degeneration. Thirty-one out of 83 patients (36.1%) showed radiographic evidence of adjacent segment degeneration. Patients with normal C7 plumb line and normal sacral inclination in the immediate post operative radiographs had the lowest incidence of adjacent level change compared with patients who had abnormality in one or both of these parameters. The difference was statistically significant (P<0.02). There was no statistically significant difference in the incidence of adjacent level degeneration between male and female patients; between posterior fusion alone and combined posterolateral and posterior interbody fusions; and between fusions extending down to the sacrum and fusions stopping short of the sacrum. It was concluded was that normality of sacral inclination is an important parameter for minimizing the incidence of adjacent level degeneration. Retrolisthesis was the most common type of adjacent segment change. Patients with post operative sagittal plane abnormalities should preferably be followed-up for at least 5 years to detect adjacent level changes.

Female↗

Frequent FGFR3 mutations in papillary non-invasive bladder (pTa) tumors.

We recently identified activating mutations of fibroblast growth factor receptor 3 (FGFR3) in bladder carcinoma. In this study we assessed the incidence of FGFR3 mutations in a series of 132 bladder carcinomas: 20 carcinoma in situ (CIS), 50 pTa, 19 pT1, and 43 pT2-4. All 48 mutations identified were identical to the germinal activating mutations that cause thanatophoric dysplasia, a lethal form of dwarfism. The S249C mutation, found in 33 of the 48 mutated tumors, was the most common. The frequency of mutations was higher in pTa tumors (37 of 50, 74%) than in CIS (0 of 20, 0%; P < 0.0001), pT1 (4 of 19, 21%; P < 0.0001) and pT2-4 tumors (7 of 43, 16%; P < 0.0001). FGFR3 mutations were detected in 27 of 32 (84%) G1, 16 of 29 (55%) G2, and 5 of 71 (7%) G3 tumors. This association between FGFR3 mutations and low grade was highly significant (P < 0.0001). FGFR3 is the first gene found to be mutated at a high frequency in pTa tumors. The absence of FGFR3 mutations in CIS and the low frequency of FGFR3 mutations in pT1 and pT2-4 tumors are consistent with the model of bladder tumor progression in which the most common precursor of pT1 and pT2-4 tumors is CIS.

Carcinoma in Situ↗

Prospective patient-reported continence after laparoscopic radical prostatectomy.

OBJECTIVES: To perform a prospective study using confidential patient-completed questionnaires about their urinary habits before and after laparoscopic radical prostatectomy. Published reports on urinary continence after radical prostatectomy vary depending on the definitions of urinary continence and methods of data collection. METHODS: From May 1998 to February 2000, 228 men underwent laparoscopic radical prostatectomy for clinically localized prostate cancer. The patients were given questionnaires before surgery and at 1, 3, 6, and 12 months postoperatively. RESULTS: Before surgery, no patient reported incontinence. At 1, 3, 6, and 12 months postoperatively, perfect diurnal urinary control (no pads, no leakage at all) was reported in 9.9%, 28.6%, 57.4%, and 56.8% of patients, respectively. No pads were used in 18.8%, 58.4%, 68.9%, and 78.4% at 1, 3, 6, and 12 months, respectively. No patient reported use of more than 1 pad daily at 6 months of follow-up. CONCLUSIONS: Continence after laparoscopic radical prostatectomy is comparable to the results after traditional radical retropubic prostatectomy. Ongoing use of the laparoscopic route for treating clinically localized prostate cancer is warranted.

Aged↗

Phase II study of vinorelbine in patients with androgen-independent prostate cancer.

PURPOSE: To evaluate the efficacy and toxicity of vinorelbine in a phase II study in patients with progressive metastatic androgen-independent prostate cancer. PATIENTS AND METHODS: Forty-seven men with progressive metastatic prostate cancer refractory to first-line or second-line hormonal therapy were treated with vinorelbine, a semisynthetic vinca-alkaloid. Vinorelbine was given, on an outpatient schedule, at 25 mg/m2 weekly for at least eight weeks or until progression or excessive toxicity. RESULTS: Forty-seven patients were included in the study, 33 being evaluable for tumour response, 36 for response to PSA, 21 for clinical benefit and 45 for toxicity. Median actual weekly dose was 19 mg/m2 (range 12.0-26.2 mg/m2). Six of thirty-six patients (17%) demonstrated a biologic response with a 50% or more decline in serum PSA on two consecutive measurements taken at least two weeks apart. The median duration of biologic response was 2.7 months. Two of three patients with measurable disease obtained an objective response but remained unconfirmed. No change disease was reported in 23 patients (49%). On entry into the study, 30 patients had symptomatic bone pain and required narcotic or non-narcotic analgesics. Clinical benefit from vinorelbine was achieved in 15 patients out of 21 (32% of the intent to treat analysis population and 71% of the assessable patients). Due to the low number of questionnaires (QLQ-C30) filled in, it was insufficient to allow any statistical analysis. The median survival was 10.2 months. Toxicity was mainly haematologic with 51% of patients experiencing grade 3 or 4 granulocytopenia. Three patients developed deep vein thrombosis. Non-haematologic toxicity, mainly nausea and neurotoxicity, was mild. CONCLUSION: The administration of weekly vinorelbine appears to be a safe treatment for those patients with androgen-independent prostate cancer and poor prognosis features who require chemotherapy. These results provide data for future investigation of vinorelbine in combination regimens.

Adenocarcinoma↗

Hormone-refractory prostate cancer: a multi-step and multi-event process.

Since the pioneering studies of Huggins in 1941, it has been known that prostate cancer cells, like certain normal epithelial cells, can chronically depend on a critical level of androgenic stimulation for their continuous growth and survival. The entire issue of the development of resistance to androgen ablation therapy for metastatic prostate cancer is based on the fact that a portion of cells can survive without androgen stimulation. The cell mechanism of androgen independent status is unclear. For some authors, a portion of the cells present within a patient with a prostate cancer before therapy is naturally androgen independent (selection hypothesis). However, this hypothesis does not consider gene alteration during prostate cancer natural history and probably hormone-refractory prostate cancer (HRPC) is due to a multi-step and multi-event process. In this literature review, different cell pathways that lead to HRPC are described.Prostate Cancer and Prostatic Diseases (2001) 4, 204-212.

Journal Article↗

Experience with retroperitoneal laparoscopic adrenalectomy for pheochromocytoma.

PURPOSE: Although laparoscopic adrenalectomy has become the preferred surgical treatment of benign adrenal masses, for pheochromocytoma it is limited by concerns over hypertensive events related to early access to the adrenal vein. We report our experience with retroperitoneal laparoscopic adrenalectomy for pheochromocytoma. MATERIALS AND METHODS: From January 1995 to December 1999, 21 retroperitoneal laparoscopic adrenalectomies (left 12 and right 9) were performed for symptomatic pheochromocytoma in 11 men and 9 women 17 to 68 years old (mean age 46). To our knowledge pheochromocytoma was always diagnosed by increased urinary catecholamine, computerized tomography, magnetic resonance imaging and 131iodine iobenguane scintigraphy. RESULTS: There were no conversions to open surgery. The operating time ranged from 100 to 150 minutes (mean 116). Mean blood loss was 140 ml. (minimum 550), and none of the patients required transfusion. Hemorrhage due to adrenal vein injury occurred in 1 patient and was controlled intraoperatively. Average postoperative hospital stay was 3.4 days (range 1 to 12). The mean diameter of the excised masses was 38 mm. (range 15 to 70). Postoperative complications occurred in 4 cases, including hematoma in 1, trocar wound infections in 2 and eventration in 1 after 1 year. With a mean followup of 21.6 months (range 6 to 46), all patients had normal urinary catecholamine levels and 18 had normal blood pressure without treatment. CONCLUSIONS: Retroperitoneal laparoscopic adrenalectomy can be safely performed for small (less than 5 cm. diameter) pheochromocytoma. Retroperitoneal laparoscopy is a direct approach that allows the surgeon to control the adrenal vein first, thereby avoiding hypertensive events.

Adolescent↗

Laparoscopic radical prostatectomy with a remote controlled robot.

PURPOSE: Robotics in surgery is a recent innovation. This technology offers a number of attractive features in laparoscopy. It overcomes the difficulties with fixed port sites by restoring all 6 degrees of freedom at the instrument tips, provides new possibilities for miniaturization of surgical tasks and allows remote controlled surgery. We investigated the applicability of remote controlled robotic surgery to laparoscopic radical prostatectomy. MATERIALS AND METHODS: Our previous experience with laparoscopic prostatectomy served as a basis for adapting robotic surgery to this procedure. A surgeon at a different location who activated the tele-manipulators of the da Vinci* robotic system performed all steps of the intervention. A scrub nurse and second surgeon who stood at patient side had limited roles to port and instrument placement, exposure of the operative field, assistance in hemostasis and removal of the operative specimen. Our patient was a 63-year-old man presenting with a T1c tumor discovered on 1 positive sextant biopsy with a 3+3 Gleason score and 7 ng./ml. preoperative serum prostate specific antigen. RESULTS: The robot provided an ergonomic surgical environment and remarkable dexterity enhancement. Operating time was 420 minutes, and the hospital stay lasted 4 days. The bladder catheter was removed 3 days postoperatively, and 1 week later the patient was fully continent. Pathological examination showed a pT3a tumor with negative margins. CONCLUSIONS: Robotically assisted laparoscopic radical prostatectomy is feasible. This new technology enhances surgical dexterity. Further developments in this field may have new applications in laparoscopic tele-surgery.

Humans↗

Laparoscopic radical prostatectomy. The Créteil experience.

OBJECTIVES: In an effort to reduce the morbidity associated to radical prostatectomy, we implemented laparoscopic surgery to this advanced ablative and reconstructive procedure. In our study, we describe our operative technique and assess our results in terms of oncologic cure, continence and potency. METHODS: 200 patients with clinically localized prostate cancer underwent laparoscopic radical prostatectomy. 66 of these patients were either referred, or operated during surgical demonstrations. Thus, complete evaluation is based on a homogeneous personal series of 134 patients and was performed by an independent clinical analyst. There were 91 T1 and 43 T2. We did not perform pelvic lymph node excision in 78 patients whose PSA was less than 10 ng/ml and the Gleason score of endorectal biopsies was below 7. The surgical procedure recapitulated the steps of traditional retropubic prostatectomy with one basic difference however: the first step of the technique consisted in a rectoprostatic cleavage, which was done transperitoneally. Except for the first 10 patients, the vesicourethral reconstruction was performed either with two hemi-circumferential or a single circumferential running suture. RESULTS: All interventions were performed as planned, no conversions were necessary, and only 4 patients required blood transfusion. Operating time decreased with growing experience; after the first 20 patients the usual operating time was 3.5 h without and 4 h with lymphadenectomy. The surgical complication rate was 22.5% in the first 40 patients, and 3.2% in the remaining 94 patients. Except for the first 10 patients, the mean hospital stay was 6.1 days and bladder catheterization 4.8 days. Median catheterization time was 4 days. Histological study of the specimen showed pT2 disease in 101 patients and pT3 in 33 patients, the rate of positive margins was 16.8 and 48.8%, respectively. At 1 year, overall erection rate (with or without sexual intercourse) was 56%, the rate of patients without pad was 86.2% during the day and 100% during the night. CONCLUSIONS: Laparoscopic environment seems to comply with the oncologic goals of radical prostatectomy. Improved intraoperative visualization and magnification may provide benefits for the preservation of continence and potency by allowing a more precise dissection and vesicourethral reconstruction. Despite longer operative times and the steep learning curve this new technique is currently proliferating due to expectations of decreased postoperative morbidity and better quality of life.

Aged↗

Retroperitoneal laparoscopic living-donor nephrectomy. Preliminary results.

PURPOSE: Living-donor nephrectomy is performed via a standard flank approach during open surgery in contrast to laparoscopy where kidneys are procured transperitoneally. Being more familiar with retroperitoneal laparoscopy for the surgery of the upper urinary tract, we investigated the feasibility of live donor nephrectomy by this approach. MATERIAL AND METHODS: We performed laparoscopic retroperitoneal left-sided nephrectomy in 3 living donors. The patients were placed in lumbotomy position. The retroperitoneal space was developed with blunt finger dissection, through a 2-cm mini-lumbotomy under the 12th rib in the posterior axillary line. 5 trocars were inserted. After primary access to the renal artery and vein, these were dissected to their junctions with the aorta and inferior vena cava, respectively, before freeing the kidney of its perinephric attachments. The kidney was delivered manually, through the slightly enlarged initial subcostal incision. RESULTS: The average duration of surgery was 83 min; warm ischemia time less than 5 min. Average blood loss was 120 cm(3). Donors did not present any postoperative morbidity and were discharged after an average of 2.3 days. Mean analgesic requirement was 5 mg morphine sulphate equivalent (0-15). Average convalescence was 13.3 days (10-18). All 3 kidneys harvested laparoscopically had immediate function with urine production after graft revascularization; serum creatinine levels returned to normal within 1 week. The first patient presented ureteral stenosis 2 months after surgery. He underwent ureteropyeloplasty using his native ureter. CONCLUSIONS: Laparoscopic living-related-donor nephrectomy become a new standard for organ harvesting. Our data suggest that retroperitoneal laparoscopic donor nephrectomy may represent a reasonable option in centers in which more extensive experience has been accumulated with retroperitoneal than with transperitoneal laparoscopy for the surgery of the upper urinary tract.

Female↗