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Biomedical subjects

A Le Duc

Publications and source records attributed to A Le Duc.

At least 55 records · Page 3Linked to original sources
PubMed1997

Microscopic study of the pig ureteral urothelium.

PURPOSE: To characterize the structure of normal pig ureteral urothelium. MATERIALS AND METHODS: Normal ureters of adult pigs [Large White] were studied by light microscopy. Cells were stained histochemically for glycogen and mucin with Periodic Acid Shiff and Alcian Blue. RESULTS: Pig urothelium has a comparable structure to that of man: transitional epithelium comprising 4 to 5 cell layers. However, several mucinous cells are seen between the urothelial cells. CONCLUSIONS: The pig ureter differs from human ureter due to the presence of mucinous cells in the ureteral urothelium under normal conditions. This feature must be taken into account in the interpretation of experimental results obtained with this model.

Animals↗
PubMed1997

Evaluation of optimal stent size after antegrade endopyelotomy: an experimental study in the porcine model.

OBJECTIVES: To investigate the influence of two sizes of internal ureteral stents, 7 F and 12 F, on ureteropelvic junction (UPJ) healing after antegrade endopyelotomy. METHODS: A right UPJ stricture was created in 10 pigs using an open surgical retroperitoneal approach. This model of obstruction consists of initially bridging the UPJ with a Terumo guide wire through an upper third ureterotomy and securing two 2.0 chronic gut ties around the UPJ over the guide wire and a 6 F ureteral catheter. The ureteral catheter is then withdrawn and the guide wire left in situ coiled up within the lumbar wall and fixed to the urogenital opening. Eight days later, each UPJ stricture was incised percutaneously using the invagination technique. Five pigs received a 7 F double-pigtail ureteral stent, while the remaining 5 pigs received a 12/7 F internal endopyelotomy stent. These stents were removed 1 week later. Retrograde ureteropyelography was performed at three months and the UPJ were examined grossly and harvested for histologic studies. RESULTS: One of the 5 pigs in each study group developed a recurrent stricture. The two groups were not statistically different in terms of histologic findings, although fibrosis of the muscle layer was more pronounced in the 12 F group. CONCLUSION: The use of a large caliber stent after experimental antegrade endopyelotomy does not provide any advantage over the use of a smaller easily positioned 7 F stent.

Animals↗
PubMed1996

Percentage of free serum prostate-specific antigen: a new tool in the early diagnosis of prostatic cancer.

Prostate-specific antigen (PSA) is a protease able to bind to serum antiproteases as alpha 1 antichymotrypsin (ACT). Free PSA (FPSA) corresponds to the fraction of total PSA (TPSA) which is unbound to ACT. Specific detection of the FPSA seems to be a valuable tool in the distinction between prostatic cancer (PCa) and benign prostatic hyperplasia (BPH). Our aim was to evaluate retrospectively the FPSA/TPSA ratio in comparison to TPSA or FPSA determination, using two new immunoradiometric assays (PSA-RIACT and FPSA-RIACT, CIS bio international, Gif Sur Yvette, France) in the early diagnosis of PCa. 256 men, with TPSA levels between 0.7 and 44.7 ng/ml (median age = 69 years), including 164 sera obtained from patients with BPH and 92 sera from patients with untreated PCa were assayed. All diagnoses were histologically confirmed and patients tested before any adjuvant treatment. The evaluation of the median FPSA/TPSA ratio in the two groups showed significantly different values (BPH group: 24.2%, PCa group: 12.1%, P < 0.0001). By R.O.C. (Receiver-Operating-Characteristics) analysis, we show that the FPSA/TPSA ratio is the method of choice for discriminating BPH and PCa, since the area under curve is the greatest for the FPSA/TPSA ratio curve, as compared to the TPSA or FPSA curves (P < 0.0001). The best accuracy (number of true positive + true negative/total = 82.4%) was obtained with a FPSA/TPSA ratio < or = 15% with high odds ratio (20.5; confidence interval (CI): 11.2; 37.7). Of interest, similar results were also confirmed even in the subpopulation with serum TPSA levels between 2.5 and 10 ng/ml (161 patients including 99 BPH and 62 PCa). We thus confirm that combined serum measurement of FPSA and TPSA is of particular interest in the early diagnosis of PCa for patients with non-suspicious digital rectal examination and a TPSA value between 2.5 and 10 ng/ml. In those patients, biopsy should be reserved to the cases with FPSA/TPSA below 15%, which allows significant odds ratio (12.8; CI: 5.2; 31.4). Otherwise, to avoid the risk of missing any PCa, usual follow-up with combined TPSA and FPSA determination would be required with the same criteria of biopsy (i.e. FPSA/TPSA ratio < or = 15% when TPSA value is between 2.5 and 10 ng/ml; or TPSA > 10 ng/ml).

Adult↗
PubMed1996

Laparoscopic fibrin glue ureteral anastomosis: experimental study in the porcine model.

Laparoscopic suturing is still difficult and time-consuming. The aim of this study, using the porcine model, was to evaluate the feasibility, safety, and efficacy of laparoscopic fibrin glue ureteral anastomosis without stay sutures for approximating the ureteral ends. In five pigs, after bilateral cystoscopic insertion of a 7F ureteral catheter, each upper ureter was laparoscopically dissected free and transected with scissors. The ureteral ends were then approximated with two atraumatic grasping forceps, and the fibrin glue was applied over the anastomotic site using a specially designed catheter (Duplocath). After waiting 5 minutes for the sealant to adhere, the forceps were removed, and the anastomotic site was examined for any early disruption. The ureteral stents were then pulled back to the distal ureter, and retrograde ureteropyelography was accomplished bilaterally in order to assess the immediate patency of the anastomoses. The animals were sacrificed and the ureteral anastomoses surgically removed for histologic examination. The operative time after insertion of the trocars averaged 15 minutes for each anastomosis, and no early disruption was observed after withdrawal of the grasping forceps. Immediate ureteral fluoroscopic patency was achieved in all 10 ureteral anastomoses, without leakage in 8 and with minimal leakage in 2. Histologic examination revealed a mild inflammatory reaction in the serosa with no modifications of the mucosa or the muscularis. Subsequently, two pigs were subjected to the same procedure bilaterally and not sacrificed. These two animals died with enormous urinomas on postoperative days 6 and 8. In each case, the anastomotic site was completely disrupted on one side, while the other side remained grossly patent. However, histologic examination of these latter anastomoses revealed no real coaptation of the ureteral ends, while demonstrating complete eversion of the mucosa. In conclusion, fibrin glue ureteroureterostomies, although easy to accomplish, are not safe enough to be used without stay sutures in laparoscopic surgery.

Anastomosis, Surgical↗
PubMed1996

[Cooling shell in renal transplantation. Thermometric evaluation of a prototype].

We have developed a cooling system for renal transplants designed to eliminate the second period of warm ischaemia corresponding to the vascular anastomosis phase of renal transplantation. This is an autonomous and independent system which forms a shell around the transplant. Following application of the system, cooling is achieved by refrigeration of a Multitherm sponge contained in the wall of the shell. The thermometric characteristics of a prototype were evaluated in vitro and in vivo in pigs. This system allows the kidney to be preserved at a temperature of less than 10 degrees C for 1 hour without inducing any risk of lesions of the renal surface. Human applications should be developed in the near future.

Anastomosis, Surgical↗
PubMed1996

Argon laser induced autofluorescence may distinguish between normal and tumor human urothelial cells: a microspectrofluorimetric study.

PURPOSE: To assess the ability of argon laser-induced autofluorescence spectroscopy (LIAFS) to discriminate normal from tumor human urothelial cells. MATERIALS AND METHODS: Emission spectra of single living cells excited at 488 nm. have been studied with confocal microspectrofluorimeter. RESULTS: Cellular autofluorescence appeared as a broad band with a maximum in the same "green" spectral range, 550 to 560 nm., probably corresponding to oxidized flavoprotein emission. However, the maximum autofluorescence intensity of normal urothelial cells was much higher, 10 times (p<0.0001) that of any of the tumor cell types tested. CONCLUSIONS: These results, suggesting a significantly reduced oxidized flavoprotein concentration in tumor urothelial cells, should prompt us to evaluate argon LIAFS as a potential tool to detect occult urothelial severe dysplasia and carcinoma in situ.

Argon↗
PubMed1996

Plasma neuroendocrine markers in patients with benign prostatic hyperplasia and prostatic carcinoma.

PURPOSE: Approximately 50% of all malignant prostatic tumors contain neuroendocrine cells, which cannot be attributed to small cell prostatic carcinoma or carcinoid-like tumors, and which represent only 1 to 2% of all prostatic malignancies. Only limited data are available concerning the plasma levels of neuroendocrine markers in patients with prostatic tumors. Therefore, we determine the incidence of high plasma levels of neuroendocrine markers in patients with benign and malignant prostatic disease. MATERIALS AND METHODS: The presence of elevated plasma neuropeptide levels was investigated in 135 patients with prostatic carcinoma and 28 with benign prostatic hyperplasia. Plasma chromogranin A, neurone-specific enolase, substance P, calcitonin, somatostatin, neurotensin and bombesin levels were analyzed by immunoassays, and were compared to clinical and pathological stages of disease. Plasma prostatic acid phosphatase and prostate specific antigen levels were also determined. All patients were followed for at least 2 years after inclusion in the study. RESULTS: Significantly elevated levels of chromogranin A were detected in 15% of patients with prostatic carcinoma before any treatment. During hormone resistant prostate cancer progression plasma chromogranin A and neuron-specific enolase levels were elevated in 55% and 30% of the patients, respectively. In patients with stage D3 disease survival curves were generated by the Kaplan-Meier method, and log rank analysis revealed a statistically significant difference between groups positive and negative for chromogranin A. Substance P and bombesin were also occasionally elevated in prostatic tumors. Determination of neuroendocrine differentiation by neuron-specific enolase or chromogranin A immunoassays was not helpful in the prediction of progressive localized prostatic carcinoma. CONCLUSIONS: Future studies of plasma neuropeptide levels should confirm whether these parameters can be used as prognostic markers during late progression of prostatic carcinoma or for the selection of patients suitable for evaluation of new antineoplastic drugs to be active against neuroendocrine tumors.

Acid Phosphatase↗
PubMed1996

[Sexually transmitted diseases in men].

Sexually transmitted diseases (STD) constitute a frequent presenting complaint. The epidemiology of human immunodeficiency virus (HIV) infection is identical to that of STD and must therefore be systematically investigated in the presence of any STD. Chlamydia trachomatis (CT) is involved in the majority of cases of urethritis and epididymitis in young subjects and is present in the urethra of 10% of subjects with a genital ulcer. Genital ulcers are due to either Treponema Pallidum, Haemophilus ducreyi, or Herpes simplex virus: there is little clinicobacteriological correlation and it is therefore essential to perform laboratory examinations in order to establish the diagnosis. The prevalence of venereal vegetations due to HPV viruses has increased markedly over recent years and require effective treatment and surveillance because of the risk of carcinoma induced by viral oncogenesis. Other viral diseases such as hepatitis B are also classified as STD. The main diagnostic techniques used at the present time for each STD are reviewed and the consensually accepted therapeutic protocols are also proposed.

Epididymitis↗
PubMed1996

[The PROGENE study, the French project of genetic analysis of familial prostatic cancer: recruitment and analysis].

OBJECTIVES: To initiate a genetic linkage study in order to localize one or several predisposition gene(s) for hereditary prostatic cancer (PC), as various epidemiological studies have demonstrated a possible family aggregation in about 25% of cases. A family segregation study [14] has also shown that a genetic predisposition, with autosomal dominant transmission and high penetrance (88% at 85 years) could be responsible for 9% of all PC. METHODS: A national collection of families with at least 2 cases of PC allowed: 1) identification of families with hereditary forms of PC, 2) creation of a constitutional DNA bank after collecting blood samples from subjects belonging to these families, and 3) a simulation study of genetic linkage analysis prior to microsatellite genotyping. RESULTS: From July 1994 to September 1995, we included 67 families (180 cases of PC). Another 45 families are currently being included. 24 of these 67 families (89 PC, 54 survivors) satisfied at least one of the criteria defined in the study by CARTER et al. for hereditary forms of familial PC. Two families were also included as the 3 patients with PC were second degree relatives. A total of 26 families therefore presented a hereditary form, 18 of which (73 PC, 46 survivors) were considered to be informative for a genetic linkage study (lod score = 4 for theta = 0.001 with an 8 allele marker). The constitutional DNA of 271 individuals of these informative families was extracted from circulating cells obtained from blood samples, immortalized lymphocytes, and the genotyping was initiated for 216 microsatellite markers distributed throughout the genome, an average of every 20 cM. CONCLUSION: Although the recruitment allowed us to identify many informative families for an inherited risk of PC, the predictive study suggested a high probability for localization of a predisposition gene by genetic linkage analysis. It would therefore be possible to identify, within the families concerned, the subjects carrying the genetic anomaly and consequently at high-risk of PC. Finally, the demonstration of the locus would allow cloning and identification of the gene (s) involved.

Female↗
PubMed1996

Laser induced autofluorescence diagnosis of bladder tumors: dependence on the excitation wavelength.

PURPOSE: We assessed the ability of laser induced autofluorescence spectroscopy to distinguish neoplastic urothelial bladder lesions from normal or nonspecific inflammatory mucosa. MATERIALS AND METHODS: Three different pulsed laser excitation wavelengths were used successively: 308 nm. (xenium chloride excimer laser), 337 nm. (nitrogen laser) and 480 nm. (coumarin dye laser). The excitation light was delivered by a specially devised multifiber catheter connected to a 1 mm. core diameter silica monofiber introduced through the working channel of a standard cystoscope with saline irrigation. The captured fluorescence light was focused onto an optical multichannel analyzer detection system. Device performance was evaluated in 25 patients after obtaining consent and immediately before transurethral resection of a bladder tumor. Spectroscopic results were compared with histological findings. RESULTS: At 337 and 480 nm. excitation wavelengths the overall fluorescence intensity of bladder tumors was clearly decreased compared to normal urothelial mucosa regardless of tumor stage and grade. At the 308 nm. excitation wavelength the shape of the tumor spectra, including carcinoma in situ, was markedly different from that of normal or nonspecific inflammatory mucosa. No absolute intensity determinations were required in this situation, since a definite diagnosis could be established based on the fluorescence intensity ratio at 360 and 440 nm. CONCLUSIONS: This spectroscopic study could be particularly useful to design a simplified autofluorescence imaging device for detection of occult urothelial neoplasms.

Carcinoma in Situ↗
PubMed1996

[Genetic aspects in cancers of the prostate].

The incidence of clinical prostate cancer varies across countries and ethnic groups. Genetic and epigenetic factors have been suggested as possible explanations to these variations, although no mesological factors with clearly significant effects have been identified. About 20% of patients with prostate cancer have a family history for this disease. Several studies have reported links between prostate cancer and breast cancer, suggesting that the same loci may predispose to both diseases. Identification of one or more inherited genes associated with an increased risk of prostate cancer in some families may be useful for identifying high-risk individuals. The value of this approach has been demonstrated in other familial cancers, such as colon and breast cancer. Current goals of research in this field are to localize the gene(s) that predispose to familial prostate cancer and to identify the molecular alterations related to tumor progression in sporadic and familial prostate cancer.

Humans↗
PubMed1995

Recurrent cytogenetic alterations of prostate carcinoma and amplification of c-myc or epidermal growth factor receptor in subclones of immortalized PNT1 human prostate epithelial cell line.

To develop an experimental prostate cancer model, we immortalized normal human prostate adult epithelial cells with SV40 large-T antigen. Two sublines were derived in culture, namely PNT1A and PNT1B. They retained the characteristics of prostate epithelial cells, but did not clone in soft agarose. PNT1A occasionally formed undifferentiated adenocarcinoma tumors in nude mice, but only in the presence of matrigel. PNT1A and PNT1B displayed common cytogenetic alterations: a 10q arm deletion, which is a recurrent alteration in prostate carcinoma, chromosome losses and a translocation involving chromosome 5. An extensive study of oncogenic alterations occurring in these cells showed that PNT1A displayed c-myc gene amplification, forming an hsr on chromosome 4, as well as gene amplification, forming an hsr on chromosome 4, as well as c-myc mRNA overexpression, with a faster doubling time (25 hr); moreover, it seemed less sensitive to EGF than PNT1B. PNT1B had a doubling time identical to that of normal cells (48 hr) but displayed EGF receptor gene amplification accompanied by an increased number of EGF binding sites and sensitivity to EGF. Because both cell lines displayed cytogenetic and oncogenic alterations found in prostate cancer, as well as differing malignant potentials, they represent an interesting model for studying the progression of prostate tumors.

Adult↗
PubMed1995

Experimental study of Wallstent self-expandable metal stent in ureteral implantation.

In regard to the risk of stent obstruction, there are persistent controversies concerning the use of the Wallstent self-expandable metal stents in the ureter. Only a few clinical trials have been published to date, and, from a technical point of view, no success predictors have been identified. In an experimental study using a pig model, we have shown that neither the length of the stent (5 or 10 cm) nor an initial 1-month intubation had any influence on the outcome of the stents. Among the eight implantations studied (four 5-cm and four 10-cm stents), only one 5-cm stent was perfectly patent at 35 days. In all the remaining stents, after 35 or 90 days, constant failure was related to distal narrowing at the edge of the stent, with no difference between the 5- and 10-cm stents or between the intubated and the nonintubated stents. This distal narrowing, probably attributable to a functional discrepancy between an adynamic stented ureter and a normal underlying ureter, demands extreme caution in human applications when the ureter is normally peristaltic.

Animals↗
PubMed1995

Subcutaneous urinary diversions for palliative treatment of pelvic malignancies.

PURPOSE: We developed 2 subcutaneous urinary diversion techniques, pyelovesical bypass and anterior cutaneous nephrostomy, to improve the quality of life of patients undergoing permanent palliative percutaneous nephrostomy. MATERIALS AND METHODS: A total of 21 patients underwent either pyelovesical bypass (19) or anterior cutaneous nephrostomy (13). Technically, the percutaneous nephrostomy tube is replaced by a self-retaining expanded polytetrafluoroethylene-silicone tube tunneled underneath the skin. The distal extremity can be either introduced into the bladder, creating a pyelovesical bypass, or brought out directly through a cutaneous orifice, creating an anterior cutaneous nephrostomy. RESULTS: No tube was dislodged and none became obstructed due to incrustation or angulation. Standard percutaneous nephrostomy was necessary in 1 patient in each group. Improvement in the quality of life was stressed by all patients. Pyelovesical bypass eliminates external drainage and anterior cutaneous nephrostomy performed when the bladder is no longer functional allows for the creation of a single, easily dressed anterior stoma. CONCLUSIONS: Pyelovesical bypass and anterior cutaneous nephrostomy constitute valuable alternatives to standard permanent palliative percutaneous nephrostomy.

Aged↗
PubMed1995

Transrectal and transurethral hyperthermia versus sham treatment in benign prostatic hyperplasia: a double-blind randomized multicentre clinical trial. The French BPH Hyperthermia.

OBJECTIVE: To compare the safety and efficacy of hyperthermia for the treatment of benign prostatic hyperplasia (BPH), by either the transrectal or transurethral approach, relative to sham treatment. PATIENTS AND METHODS: Two hundred patients from seven urological departments were randomized and treated in a single centre. Principal inclusion criteria were a peak flow rate (PFR) < 15 mL/s and residual urine < 300 mL/s. Comparisons were made between transurethral hyperthermia (TUH) and transurethral sham (TUS) and between transrectal hyperthermia (TRH) and transrectal sham (TRS) 12 months after treatment. Outcome was assessed by improvements in the Madsen score and PFR, and the incidence of side-effects. RESULTS: After 12 months, 145 patients were evaluated; 12 patients withdrew during treatment, 43 withdrew during follow-up and two were lost to follow-up. Withdrawals were mainly due to side-effects during treatment (17% in the TRH and 1.5% in the TUH group) and to a lack of improvement during follow-up (14% in the TUH group, 19% in the TUS, 15% in the TRH and 10.5% in the TRS group received other treatments for BPH). Complications during treatment consisted mainly of local pain, urethral bleeding, urethral pain and acute retention, and were five times more frequent in the TRH than the TUH group (34% versus 6%). There was no improvement in PFR after TUH and TRH (response < 20%). Only TUH improved the Madsen score (TUH, +50% and TUS, +17%). CONCLUSION: Hyperthermia was not an effective treatment for BPH.

Aged↗