PET imaging of the impact of extracellular pH and MAP kinases on the p-glycoprotein (Pgp) activity.

The functional activity of p-glycoprotein (Pgp) can be increased in vitro by an extracellular acidosis via activation of MAP kinases (p38, ERK1/2). In order to study these effects in vivo a new (68)Ga-labeled PET tracer was developed which serves as a substrate of the Pgp and therefore indirectly mirrors the Pgp activity. For in vivo studies, experimental tumors were imaged under acidic conditions (inspiratory hypoxia, injection of lactic acid) and during inhibition of MAP kinases in a µ-PET system. In vitro, [(68)Ga]MFL6.MZ showed an accumulation within the cells of about 20% which was increased to 30% by Pgp inhibition. In solid tumors a marked tracer uptake was observed showing spatial heterogeneity. When the tumors were acidified, the PET tracer accumulation was reduced by 20-30%. Changing the inspiratory O(2)-fraction to 8% led dynamically to a decrease in pH and in parallel to a reduced tracer concentration. Inhibition of the p38 pathway reduced the Pgp transport rate. The new (68)Ga-labeled tracer is suitable for PET imaging of the tissue Pgp activity. In vivo imaging reveals that an acidosis activates the Pgp markedly, a mechanism in which the p38-MAPK pathway seems to play an important role.

Assessing p-glycoprotein (Pgp) activity in vivo utilizing 68Ga-Schiff base complexes.

PURPOSE: The p-glycoprotein (Pgp) is the most prominent member of active drug transporters leading to a multidrug-resistant phenotype. For identification of tumors functionally overexpressing Pgp in vivo, non-invasive imaging techniques are needed. PROCEDURES: Six Schiff base compounds were synthesized and labeled with (68)Ge/(68)Ga generator-derived (68)Ga. The compounds were studied in vitro in Pgp-positive tumor cells. The property of being a Pgp substrate was tested by comparison of the tracers uptake in R-3327 Dunning prostate carcinoma AT1 cells in presence and absence of the Pgp-inhibitor verapamil. In vivo investigations were performed with tumor-bearing rats imaged with micro-positron emission tomography. RESULTS: All ligands were labeled with (68)Ga in yields of >92% beside one (~55%). The tracers showed different accumulation within the cells in vitro (4-60%). In blocking experiments, the ratio (blocked to unblocked) varied from 1.8 to 1.0. For in vivo experiments, (68)Ga-ENBDMPI and (68)Ga-MFL6.MZ were selected. The tumors showed specific uptake of the tracer. Direct intratumoral injection of verapamil increased the tracer concentration by ~25% reflecting the functional Pgp activity. CONCLUSIONS: Two (68)Ga-labeled ligands appear to be valuable for imaging non-invasively the intratumoral Pgp activity. On a long term, patients with multidrug-resistant tumors pre-therapeutically may be identified prior to treatment.

Activation of P-glycoprotein (Pgp)-mediated drug efflux by extracellular acidosis: in vivo imaging with 68Ga-labelled PET tracer.

PURPOSE: In vitro it has been shown that the functional activity of P-glycoprotein (Pgp), an important drug transporter responsible for multidrug resistance, can be strongly increased by extracellular acidosis. Here mitogen-activated protein kinases (MAPK) (p38, ERK1/2) seem to play an important role for signal transduction. However, it is unclear whether these effects are also relevant in vivo. METHODS: With the newly developed PET tracer Schiff base-based (68)Ga-MFL6.MZ the functional Pgp activity was visualized under acidic conditions and during inhibition of MAPKs non-invasively by means of microPET in rat tumours. Tumours were acidified either by inspiratory hypoxia (8% O(2)) or by injection of lactic acid. Inhibitors of the MAPK were injected intratumourally. RESULTS: With increasing tumour volume the tumour pH changed from 7.0 to 6.7 and simultaneously the Pgp activity increased almost linearly. When the tumour was acidified by direct lactic acid injection the PET tracer uptake was reduced by 20% indicating a higher transport rate out of the cells. Changing the inspiratory O(2) fraction to 8% dynamically led to a reduction of extracellular pH and in parallel to a decrease of tracer concentration. While inhibition of the p38 pathway reduced the Pgp transport rate, inhibition of ERK1/2 had practically no impact. CONCLUSION: An acidic extracellular environment significantly stimulates the Pgp activity. The p38 MAPK pathway plays an important role for Pgp regulation in vivo, whereas ERK1/2 is of minor importance. From these results new strategies for overcoming multidrug resistance (e.g. reducing tumour acidosis, inhibition of p38) may be developed.

Laparoscopic radical prostatectomy in men older than 70 years of age with localized prostate cancer: comparison of morbidity, reconvalescence, and short-term clinical outcomes between younger and older men.

OBJECTIVES: To analyze the safety and efficacy of extraperitoneal laparoscopic radical prostatectomy (eL-RPE) in elderly versus younger men with localized prostate cancer. METHODS: Patients undergoing eL-RPE were retrospectively subdivided into group eL-RPE1 (72 men aged 71 yr and older) and group eL-RPE2 (132 men aged 59 yr and younger). Group eL-RPE1 was compared with a group of 70 contemporary, comparable patients aged 71 yr and older undergoing open retropubic radical prostatectomy (group OPEN-RPE). RESULTS: Compared with group eL-RPE2, patients of group eL-RPE1 had a higher pathologic stage (45% vs. 32% stage pT3 or greater, p<0.001) and higher Gleason score (median 7 vs. 6, p<0.001). Prostate-specific antigen recurrence was significantly worse compared with age-matched controls for younger patients with high-stage or high-grade lesions (p<0.001). Importantly operative time, analgesic requirements, hospital stay, convalescence, and complication rates were comparable. Urinary continence rate was significantly better in group eL-RPE2 at 6 mo (67% vs. 91%, respectively, p<0.001). Group eL-RPE1 and group OPEN-RPE patients had statistically similar pathologic stage and Gleason score (each p>0.05), similar operative time (p=0.12), but less blood loss (p<0.001), shorter hospital stay (p<0.001), and more rapid convalescence (p<0.001) occurred in eL-RPE1. CONCLUSIONS: eL-RPE is feasible and efficacious even in elderly patients with unfavorable, large-volume disease. eL-RPE offers the advantages of decreased blood loss, shorter hospital stay, and more rapid recovery over OPEN-RPE. However, the elderly patient must be informed preoperatively about the observed higher incontinence rate.

Vesicourethral anastomosis during endoscopic extraperitoneal radical prostatectomy: a prospective comparison between the single-knot running and interrupted technique.

OBJECTIVES: To determine the safety and efficacy of the single-knot running versus interrupted technique for urethrovesical anastomosis during endoscopic extraperitoneal radical prostatectomy. METHODS: A total of 250 consecutive patients who underwent endoscopic extraperitoneal radical prostatectomy were prospectively divided into two groups of 125 patients each who underwent urethrovesical anastomosis using the single-knot running technique (group 1) or the interrupted suture technique (group 2). Surgical data, operative time, difficulty scores, extravasation rate, catheterization time, occurrence of anastomotic strictures, and the early and late continence rates were analyzed statistically. RESULTS: Regarding the clinical and pathologic findings, extravasation rate, catheterization time, and occurrence of anastomotic strictures, no significant differences were found between the two groups (P >0.05). The strongest independent predictors for extravasation were the integrity of the dorsal wall of the anastomosis and the degree of bladder neck opening (P <0.001). Overall, the continence rate at 3 and 6 months was 76% and 91.5% for group 1 and 77.6% and 93% for group 2, respectively (all P >0.05). The anastomosis technique had no impact on extravasation or continence status (all P >0.05). The only significant differences (P <0.001) in favor of the single-knot technique were the mean operative time and difficulty score (16 versus 24 minutes and 1 versus 3, respectively). CONCLUSIONS: Both techniques provide satisfactory and similar functional results. However, because of its simplicity and shorter operative time, the single-knot running technique appears preferable.

Quality of life after laparoscopic and open retroperitoneal lymph node dissection in clinical Stage I nonseminomatous germ cell tumor: a comparison study.

OBJECTIVES: To compare the postoperative quality of life (QOL) and reconvalescence in patients with clinical Stage I nonseminomatous germ cell tumor (NSGCT) after laparoscopic retroperitoneal lymph node dissection (L-RPLND) and the open procedure (O-RPLND). METHODS: Twenty-one patients with NSGCT who underwent transperitoneal L-RPLND were matched and compared with 29 patients who underwent O-RPLND. The operative, QOL, and recovery data and complications and cure rates were analyzed for both groups. RESULTS: The mean follow-up time for the L-RPLND and O-RPLND groups was 14 months (range 6 to 20) and 26 months (range 8 to 38), respectively. No major complication requiring open surgical revision or prolongation of hospitalization was observed intraoperatively or postoperatively in either group. However, the early and late minor postoperative complications were significantly greater in the O-RPLND group than in the L-RPLND group (P <0.001). The L-RPLND patients had a significantly shorter hospitalization, greater QOL scores, and a faster return to normal activities than did the O-RPLND patients (all P <0.001). CONCLUSIONS: L-RPLND for patients with clinical Stage I NSGCT is a safe and efficacious procedure, with a faster reconvalescence and greater postoperative QOL than after O-RPLND.

Laparoscopic radical prostatectomy: impact of modified apical and posterolateral dissection in reduction of positive surgical margins in patients with clinical stage T2 prostate cancer and high risk of extracapsular extension.

PURPOSE: To determine whether modifications of extraperitoneal endoscopic radical prostatectomy (EERP) reduce the rate of a positive surgical margin (PSM) in men with clinical stage T(2) prostate cancer and a high risk of extracapsular extension. PATIENTS AND METHODS: A consecutive series of 182 men with stage cT(2) tumors and a high risk of extracapsular extension underwent EERP by a single surgeon (VP). The patients were divided into two groups: 71 patients who underwent a standard EERP (group 1) and 111 patients who underwent EERP with the modified technique (group 2). The basic principles of the modified technique are more thorough and wider resection of the posterolateral prostatic pedicles and extensive excision of periprostatic soft tissue at the apex, which results in better mobilization and exposure of the apex before the urethral transection. Differences in PSM rates were analyzed statistically. RESULTS: No significant differences were found between the two groups regarding the clinical and pathologic findings (P > 0.05). The rate of PSM was 28% in group 1 and 10% in group 2 (P < 0.001). Group 2 was less than one third as likely to have PSM as group 2 (odds ratio 2.9; 95% confidence interval 1.6, 3.9). The strongest (P < 0.0001) independent predictors of PSM were the surgical technique, the presence of extracapsular disease, and the volume of the cancer. Preservation of the neurovascular bundles had no impact on margin status (P = 0.93). Functional outcomes and complication rates were not adversely affected by these modifications. CONCLUSION: The modified dissection in EERP significantly reduces the rate of PSM in patients with stage cT(2) prostate cancer and a high risk of extracapsular extension.

Extracorporeal shockwave therapy for Peyronie's disease: an alternative treatment?

AIM: To determine retrospectively the safety and efficacy of extracorporeal shock wave therapy (ESWT) in patients with Peyronie's disease. METHODS: Fifty-three patients with stable Peyronie's disease underwent ESWT (group 1). Fifteen patients matched with the baseline characteristic of the patients in group 1, who received no treatment, were used as the control (group 2). The patients' erectile function (International Index of Erectile Function [IIEF-5] score), pain severity (visual analog scale), plaque size and degree of penile angulation were assessed before and after the treatment in group 1 and during the follow-up in group 2. RESULTS: The mean follow-up time was 32 months (range: 6-64 months) in group 1 and 35 months (range: 9-48 months) in group 2. All the patients were available for the follow-up. Considering erectile function and plaque size, no significant changes (P > 0.05) were observed in group 1 before or after the ESWT. A total of 39 patients (74%) reported a significant effect in pain relief in group 1 after ESWT. However, regarding improvement in pain, IIEF-5 score and plaque size, no significant differences were observed between the two groups. In 21 patients (40%) of group 1, the deviation angle was decreased more than 10 degrees with a mean reduction in all patients of 11 degrees (range: 6-20 degrees). No serious complications were noted considering ESWT procedure. CONCLUSION: ESWT is a minimally invasive and safe alternative procedure for the treatment of Peyronie's disease. However, the effect of ESWT on penile pain, sexual function and plaque size remains questionable.

Intensive laparoscopic training: the impact of a simplified pelvic-trainer model for the urethrovesical anastomosis on the learning curve.

We prospectively evaluated the learning curve (LC) for laparoscopic urethrovesical anastomosis (L-UVA) in an operator-training model and program using an innovative simplified pelvic-trainer model. Over a period of 12 months, 30 LRP were performed by one urologist skilled in open surgery but inexperienced in laparoscopy. During the first 15 procedures no systematic training was done. Consequentially, a systematic simplified daily program was performed on the pelvic trainer with a videolaparoscopic unit. The training lesson consisted of intracorporal knotting and suturing, linear and circular interrupted suture anastomosis. At the end of each lesson, time and performance error scores were recorded and progression curve was plotted for each task. The performances of each training tasks were plotted against the performance of L-UVA during the LRP. The significance of progression was evaluated using logarithmic regression analysis. A steady improvement in time and accuracy of performance skill was shown during the first 20 lessons (p<0.001). These improved skill acquisitions were proportionally correlated with the time and the accuracy (water-tight) of L-UVA performance during the last 15 L-RPE. Compared to the first 15 L-RPE, where no systematic training was performed, time and accuracy of L-UVA performance in the last 15 L-RPE were improved from a mean 51 (median 48, range: 38-75) to 26 (median 24, range 18-33) min (p<0.001) and from 10 to 15 watertight anastomoses (p<0.001), respectively. Using a continuing, systematic, simplified training model the LC of L-UVA can be improved significantly in a short time.

Tension-free vaginal tape (TVT) in morbidly obese patients with severe urodynamic stress incontinence as last option treatment.

OBJECTIVES: To determine the safety and efficacy of tension-free vaginal tape (TVT) in morbidly obese women with severe urodynamic stress incontinence (USI) as last option treatment. METHODS: Thirty-one patients with body mass index (BMI) >40 kg/m2, who had undergone the TVT procedure for urodynamically-confirmed USI were matched with 52 patients with BMI <30 kg/m2 who underwent the same procedure. BMI was calculated at the time of the surgery. Patients' characteristics and surgical data, complications and cure rates were analyzed for both groups. RESULTS: After a mean follow-up of 18.5 (range: 12-24) months the continence rates were 87% and 92% for morbidly obese women and control group, respectively (p = 0.103). No serious intraoperative complications were noted in both groups. However, the early postoperative complications were significantly higher (p < 0.05) in morbidly obese patients. In 4 patients from both group long term postoperative catheterization was necessary for 4 weeks. In one patient (2%) from the control group dilatation of urethra took place. No defect in healing or rejection of the tape occurred. CONCLUSIONS: TVT is a minimal invasive and safe procedure for morbidly obese patients suffering from severe USI with good outcome. Preoperative morbid obesity does not seem to be a risk factor for failure of this procedure.

Laparoscopic radical prostatectomy using an extraperitoneal approach: Nordwest hospital technique and initial experience in 255 cases.

PURPOSE: We report on our modifications in technique and initial experience with 255 extraperitoneal laparoscopic radical prostatectomy (eLRP). PATIENTS AND METHODS: Using significant surgical modifications, our laparoscopic method replicates the steps of the retropubic descending RP. We evaluated 255 consecutive patients who underwent an eLRP with pelvic lymph-node dissection. RESULTS: The mean operative time was 136 minutes (range 84-266 minutes). Because of technical difficulty, the first three patients were converted to open surgery. One major complication, myocardial infarction, and one surgical reintervention in a case of secondary rectourethral fistula after open surgical repair of a laparoscopic rectal injury were observed. The blood transfusion rate was 1.2%. The pathologic stage was pT2a in 56 patients (22%), pT2b in 50 (20%), pT2c in 74 (29%), pT3a in 42 (16%), pT3b in 29 (11%), and pT4 in 3 (2%). Positive margins were found in 7% of patients (13/180) with pT2 tumors and 27% of patients (19/71) with pT3 tumors. The mean catheterization time was 7 days. The continence rates (no pads at all) at 3, 6, and 12 months were 73.7% (146/198), 89.6% (112/125), and 92.7% (38/41), respectively. After a nerve-sparing procedure, the total potency rates at 3 and 6 months were 37.5% (21/56) and 48.8% (21/43), respectively. CONCLUSION: The eLRP seems to be safe with short-term oncologic and functional results at least as favorable as those of open radical prostatectomy and classical transperitoneal LRP. The operative times are shorter, and the complication rate appears to be lower.

Retroperitoneoscopic versus open surgical radical nephrectomy for large renal cell carcinoma in clinical stage cT2 or cT3a: quality of life, pain and reconvalescence.

OBJECTIVES: To determine whether retroperitoneoscopic radical nephrectomy for large renal cell carcinoma in stage cT2 or cT3a is a feasible, safe and effective therapy option and if it shows any advantage regarding quality of life in comparison to open procedure. METHODS: 23 patients who underwent RPNx for tumor size greater than 7 cm (group 1) were matched and compared with 25 patients, who underwent ONx (group 2) for tumor with similar size characteristics. Patient and surgical data, QoL variables and complications were statistically analyzed. RESULTS: The median followup was 12 (range: 6-18) months for both groups. Group 1 had significantly (p < 0.001) less blood loss, shorter hospital stay, and shorter postoperative analgesic requirements. No conversion to open surgery was necessary, and no major complications requiring an invasive intervention occurred. Retroperitoneoscopic patients had significantly better QoL and pain scores postoperatively to 6 months (p < 0.001) and they return to baseline QoL status faster (p < 0.001). CONCLUSIONS: RPNx for large RCC in stage cT2 or cT3a is a safe and efficacious procedure with good short-term outcome results and significantly shorter recovery of QoL variables.

Laparoscopic radical prostatectomy: the value of intraoperative frozen sections.

OBJECTIVE: To examine the clinical and pathological value of intraoperative frozen section (IFS) in patients undergoing laparoscopic radical prostatectomy (L-RPE) for clinically localized prostate cancer. METHODS: The study includes 198 consecutive cases of L-RPE. After removal of the prostate, a 2-3mm circumferential specimen was obtained from the apical and bladder neck soft-tissue margin and submitted for IFS examination. In cases suspicious for capsular incision (n=57), IFS were taken from the neurovascular bundle/lateral pedicle. RESULTS: The IFS diagnosis from the apical, bladder neck, and neurovascular bundle/lateral pedicle soft-tissue margins was adenocarcinoma in 12 (6%), 1 (0.5%), and 2 (1%) cases, respectively. Patient age, clinical stage, and mean specimen weight were not associated with cancer at the apical IFS. The accuracy, sensitivity, specificity, positive and negative predictive value of the apical IFS to predict cancer in the permanent section of the apical soft-tissue margin was 96%, 70%, 97%, 58%, and 98%, respectively. All the patients (n=15) with cancer at IFS had wide resections of additional tissue in the area of positive soft-tissue margin and all had no cancer in the additional resected tissue. Especially at the apex, IFS decreases the overall PSM status on surgical specimen by 5.1% (apical PSM from 8.6% to 3.5%). CONCLUSION: Because of the low predictive value of IFS of bladder neck and neurovascular bundle/lateral pedicle their use is not recommended. IFS of the apex should be performed to reduce the PSM rate.

Laparoscopic radical prostatectomy: prospective evaluation of the learning curve.

OBJECTIVE: We prospectively evaluated the learning curve (LC) of laparoscopic radical prostatectomy (L-RPE) regarding the improvements in operative times (OT) and technical difficulty in one-operator-practice as it compares with open RPE. METHODS: Over 18 months, 50 L-RPE were performed by an inexperienced surgeon in laparoscopy but skilled in open surgery. Difficulty scores were obtained at the completion of each L-RPE comparing L-RPE to open RPE. OT, estimated blood loss (EBL), length of stay, and catheterization time were also obtained. RESULTS: In the ablative part of L-RPE the median difficulty score was significantly higher (p<0.001) for the first 10 cases, decreased dramatically by case 11 becoming equivalent (p=0.3) to open RPE and by case 31 the L-RPE becomes significantly easier than open RPE (p=0.002). The difficulty scores for the urethrovesical anastomosis performance is always uniformly higher for the whole patient series (p<0.001). Median OT decreased significantly from 293 minutes in the first 10 cases to 114 minutes in the last 10 cases (p<0.001). Catheterization time and length of hospitalization, decreased significantly with the progression of the LC. EBL remained stable throughout the patient cases. Obesity, prior surgery, and extension of the procedure (lymphadenectomy, nerve-sparing) significantly increased the OT. CONCLUSION: Although the ablative part of L-RPE has a relatively short LC for a skilled open surgeon reflected by the rapid decrease in difficulty scores and OT by case 21, the performance of anastomosis shows a longer LC. Intensive training on anastomosis may be necessary to master this skill.

Synthesis and preliminary evaluation of (R,R)(S,S) 5-(2-(2-[4-(2-[(18)F]fluoroethoxy)phenyl]-1-methylethylamino)-1-hydroxyethyl)-benzene-1,3-diol ([(18)F]FEFE) for the in vivo visualisation and quantification of the beta2-adrenergic receptor status in lung.

The (18)F-labeled beta2-adrenergic receptor ligand (R,R)(S,S) 5-(2-(2-[4-(2-[(18)F]fluoroethoxy)phenyl]-1-methylethylamino)-1-hydroxyethyl)-benzene-1,3-diol, a derivative of the original highly selective racemic fenoterol, was synthesized in an overall radiochemical yield of 20% after 65 min with a radiochemical purity higher than 98%. The specific activity was in the range of 50-60 GBq/micromol. In vitro testing of the non-radioactive fluorinated fenoterol derivative with isolated guinea pig trachea was conducted to obtain an IC(50) value of 60 nM. Preliminary ex vivo organ distribution and in vivo experiments with positron emission tomography (PET) on guinea pigs were performed to study the biodistribution as well as the displacement of the radiotracer to prove specific binding to the beta2-receptor.