Isothermal microcalorimetry accurately detects bacteria, tumorous microtissues, and parasitic worms in a label-free well-plate assay

Isothermal microcalorimetry is a label-free assay that allows monitoring of enzymatic and metabolic activities. The technique has strengths, but most instruments have a low throughput, which has limited their use for bioassays. Here, an isothermal microcalorimeter, equipped with a vessel holder similar to a 48-well plate, was used. The increased throughput of this microcalorimeter makes it valuable for biomedical and pharmaceutical applications. Our results show that the sensitivity of the instrument allows the detection of 3 × 10⁴ bacteria per vial. Growth of P. mirabilis in Luria Broth medium was detected between 2 and 9 h with decreasing inoculum. The culture released 2.1J with a maximum thermal power of 76 μW. The growth rate calculated using calorimetric and spectrophotometric data were 0.60 and 0.57 h^–1, respectively. Additional insight on protease activities of P. mirabilis matching the last peak in heat production could be gathered as well. Growth of tumor microtissues releasing a maximum thermal power of 2.1 μW was also monitored and corresponds to a diameter increase of the microtissues from ca. 100 to 428 μm. This opens new research avenues in cancer research, diagnostics, and development of new antitumor drugs. For parasitic worms, the technique allows assessment of parasite survival using motor and metabolic activities even with a single worm.

GreenLight laser vs diode laser vaporization of the prostate: 3-year results of a prospective nonrandomized study

BACKGROUND AND OBJECTIVE

Laser vaporization of the prostate is one of the alternatives to transurethral resection of the prostate. Short-term studies report a comparable outcome after laser vaporization with the 532 nm 120-W GreenLight high-performance system (HPS) laser and the 980 nm 200 W high-intensity diode (diode) laser. In this study, we analyzed the intermediate-term results of both techniques.

MATERIALS AND METHODS

From January 2007 to January 2008, 112 consecutive patients with symptomatic benign prostate enlargement were nonrandomly assigned to treatment with the GreenLight laser or the diode laser. Perioperative parameters, postoperative functional outcome, complications, and the reoperation rate at 3 years were analyzed.

RESULTS

Improvement of voiding symptoms (International Prostate Symptom Score, quality-of-life) and micturition parameters (maximum flow rate, postvoid residual volume) showed no significant difference between the HPS group and the diode group. A significantly higher reoperation rate was observed in the diode group in comparison to the HPS group (37.5% vs 8.9%, p=0.0003) due to obstructive necrotic tissue (16.1% vs 0%, p=0.0018), bladder neck stricture (16.1% vs 1.8%, p=0.008), and persisting or recurrent adenoma (5.4% vs 7.1%, p=0.70), respectively.

CONCLUSIONS

Both lasers lead to comparable improvement of voiding parameters and micturition symptoms. Treatment with the 200 W diode laser led to a significantly higher reoperation rate, which might be attributed to a higher degree of coagulation necrosis. Thus, a careful clinical application of this diode laser type is warranted.

Maximum tumor diameter adjusted to the risk profile predicts biochemical recurrence after radical prostatectomy

Currently, no consensus exists on the best method for tumor quantification in prostate cancer (PCA), and its prognostic value remains controversial. We evaluated how a newly defined maximum tumor diameter (MTD) might contribute to the prediction of biochemical recurrence (BCR) in a consecutive series of PCA patients treated with radical prostatectomy (RP). Patients with PCA who underwent RP without neoadjuvant therapy at a single center were included for analysis. MTD was defined as the largest diameter of all identified tumors in all three dimensions (i.e., length, width, or depth) of the prostate ("Basel technique"). Cox regression models addressed the association of MTD with BCR in three risk groups (low risk-prostate-specific antigen (PSA) < 10 ng/ml, pT2, and Gleason score (GS) ≤ 6; intermediate risk-PSA ≥ 10 and <20 ng/ml and/or pT2 and GS = 7; high risk-PSA > 20 ng/ml or pT3 or GS ≥ 8) and whole cohort. Within a median follow-up of 44 months (interquartile range (IQR) 23-66), 48 patients (9.4 %) in the intermediate-risk and high-risk groups experienced BCR. In multivariate Cox regression analysis, PSA, pathological stage (pT stage), GS, positive surgical margins (PSMs), and MTD > 19.5 mm were independent predictors for BCR (p < 0.05). In subgroup analysis, MTD as a nominal variable (<24.5 and >24.5 mm) was the only independent predictor of BCR in the intermediate-risk group (hazard ratio (HR) 9.933, 95 % confidence interval (CI) 2.070-47.665; p < 0.05). MTD is an independent risk factor of BCR in PC patients after RP. The combination of the MTD with other well-known prognostic factors after RP may improve decision-making concerning follow-up intensity or adjuvant treatment.

Stents and stone disease

The use of stents in renal stone disease is relatively new. The main advantage is reduced pressure in the renal collecting system during times of infected obstructed collecting systems, surgery or obstructing stones. As much pain relieve theses stents offer when indicated, equally much morbidity is caused when stent materials interface with the human urothelium in terms of symptoms, perforations and the "forgotten stent". This review aim to summarize some of the most important considerations when stents are used in stone disease.

The effect of increased maximum power output on perioperative and early postoperative outcome in photoselective vaporization of the prostate

BACKGROUND AND OBJECTIVE

Preclinical studies suggest an increased vaporization rate and speed of the 532 nm 180-W XPS GreenLight laser (180-W) compared with the 120-W HPS GreenLight laser (120-W) and the 80-W PV GreenLight laser (80-W). To test the clinical relevance of this observation we analyzed intraoperative data and early postoperative results after photoselective vaporization of the prostate (PVP) with the 180-W, 120-W, and 80-W laser.

STUDY DESIGN/MATERIALS AND METHODS

A retrospective pair-to-pair comparison was performed including 80 consecutive patients who underwent PVP for the treatment of benign prostate enlargement with the 180-W, 120-W, and 80-W laser. The groups matched concerning age, prostate volume, PSA-value, and preoperative catheterization. Primary study outcome measurement was PSA-value reduction at 3 months; intraoperative data, perioperative complications, and early postoperative functional course were secondary study outcome measurements.

RESULTS

Energy application per case (kJ), preoperative prostate volume (kJ/ml) operating time (kJ/minute), and lasing time (kJ/minute) was significantly higher with the 180-W laser. Prevalence of impaired visibility due to bleeding was comparable between the 180-W and the 120-W laser but significantly lower with 80-W. Duration of hospitalization was shorter with the 180-W laser compared to the former laser systems. During the postoperative course of 3 months voiding parameters and micturition symptoms significantly improved in all groups, the incidence of postoperative dysuria was comparable. Postoperative PSA-value reduction was significantly higher after treatment with the 180-W laser.

CONCLUSIONS

With the 180-W laser, higher energy application and higher speed of tissue vaporization leads to increased tissue vaporization compared to the former 120-W and 80-W laser systems. Clinical efficacy and perioperative safety are maintained with the higher powered laser.

Comparison of the roll-plate and sonication techniques in the diagnosis of microbial ureteral stent colonisation: results of the first prospective randomised study

BACKGROUND

Microbial ureteral stent colonisation (MUSC) is one leading risk factor for complications associated with ureteral stent placement. As MUSC remains frequently undetected by standard urine cultures, its definitive diagnosis depends on microbiological investigation of the stent. However, a standard reference laboratory technique for studying MUSC is still lacking.

MATERIALS AND METHODS

A total of 271 ureteral stents removed from 199 consecutive patients were investigated. Urine samples were obtained prior to device removal. Stents were divided into four parts. Each part was separately processed by the microbiology laboratory within 6 h. Ureteral stents were randomly allocated to roll-plate or sonication, respectively, and analysed using standard microbiological techniques. Demographic and clinical data were prospectively collected using a standard case-report form.

RESULTS

Overall, roll-plate showed a higher detection rate of MUSC compared with sonication (35 vs. 28 %, p < 0.05) and urine culture (35 vs. 8 %, p < 0.05). No inferiority of Maki's technique was observed even when stents were stratified according to indwelling time below or above 30 days. Compared with roll-plate, sonication commonly failed to detect Enterococcus spp., coagulase-negative staphylococci (CoNS) and Enterobacteriaceae. In addition, sonication required more hands-on time, more equipment and higher training than roll-plate in the laboratory.

CONCLUSIONS

This prospective randomised study demonstrates the superiority of Maki's roll-plate technique over sonication in the diagnosis of MUSC and that urine culture is less sensitive than both methods. The higher detection rate, simplicity and cost-effectiveness render roll-plate the methodology of choice for routine clinical investigation as well as basic laboratory research.

Complications of laser prostatectomy: a review of recent data

INTRODUCTION

Laser techniques for the treatment of bladder outlet obstruction (BOO) due to benign prostate enlargement (BPE) have emerged as an alternative to transurethral resection of the prostate (TURP) and open prostatectomy (OP).

MATERIALS AND METHODS

A Medline search over the past 4 years was performed to assess the safety, intra- and postoperative morbidity of various laser techniques.

RESULTS

Data on holmium laser enucleation of the prostate (HoLEP) show the highest grade of evidence with two meta-analyses available and prove the low intra- and postoperative morbidity with reproducible long-term results. Photoselective vaporization of the prostate (PVP) with the Greenlightlaser (potassium titanyl phosphate, KTP or lithium borate, LBO) is characterized by excellent haemostatic properties in patients with or without oral anticoagulation. Long-term results show a reoperation rate comparable with TURP; however, there is a lack of randomized trials. Various types of diode lasers with different wavelengths are available for laser vaporization; despite their favourable haemostatic properties, a higher invasion depth seems to result in necrosis of the tissue leading to a higher rate of reoperation. Thulium-laser resection of the prostate shows promising intra- and postoperative morbidity, but data are limited and initial results need to be confirmed in large-scale trials.

CONCLUSION

In summary, HoLEP- and KTP-, or LBO-laser vaporization of the prostate are the most mature techniques of laser prostatectomy and treatment alternatives to TURP and OP, whereas the clinical value and durability of procedures with diode laser systems and the thulium laser need to be confirmed in high-quality prospective RCTs.

Prospective single-centre comparison of 120-W diode-pumped solid-state high-intensity system laser vaporization of the prostate and 200-W high-intensive diode-laser ablation of the prostate for treating benign prostatic hyperplasia

OBJECTIVE

To evaluate the safety, efficacy and short-term outcome of a new 980 nm high-intensity diode (HiDi) laser (Limmer Laser, Berlin, Germany) system in comparison to the diode-pumped solid-state laser high-performance system (HPS; GreenLight(TM), AMS, Minnetonka, MI, USA) for treating benign prostatic hyperplasia (BPH) in a prospective non-randomized single-centre study.

PATIENTS AND METHODS

From February to September 2007, 117 consecutive patients with lower urinary tract symptoms secondary to BPH were included; 62 patients were treated with 120-W HPS laser vaporization and 55 with 980-nm HiDi laser ablation of the prostate. We evaluated perioperative variables, and complications during and after surgery. Patients presenting for follow-up completed the International Prostate Symptom Score, and had their maximum urinary flow rate and postvoid residual urine volume measured.

RESULTS

The mean (sd) age of the patients was 72.3 (8.8) years (HiDi) and 73.1 (10.8) years (HPS), with a mean preoperative prostate volume of 64.7 (29.7) and 67.4 (46.9) mL, respectively. The mean operative duration was comparable, at 56.4 (20.2) and 62.7 (36.3) min, respectively, whereas the mean energy delivery was significantly higher with the diode laser, at 313 (132) vs 187 (129) kJ (P < 0.001). For patients treated with the HPS the rate of visual impairment from bleeding was higher (0% vs 12.9%, P < 0.01), as was prostate capsule perforation (0% vs 4.8%, P > 0.05). Soon after surgery the rate of dysuria (23.6% vs 17.7%, P > 0.05) and transient urge incontinence (7.3% vs 0%; P < 0.05) was higher for the HiDi laser. During the follow-up there were higher rates of bladder neck stricture (14.5% vs 1.6%, P < 0.01), re-treatment (18.2% vs 1.6%, P < 0.01) and stress urinary incontinence (9.1% vs 0%; P < 0.05) for the HiDi laser group.

CONCLUSION

Both systems investigated provide good tissue ablative properties. The HiDi laser at 980 nm is more favourable in terms of haemostasis. The penetration depths, resulting in coagulation necrosis and leading to increased re-treatment, bladder neck stricture and incontinence rates, were higher with the HiDi laser.

[Diagnosis and therapy of acute ureteral colic]

Acute ureteral colic presents with a complex of acute and characteristic flank pain that usually indicates the presence of a stone in the urinary tract. Diagnosis and management of renal colic have undergone considerable evolution and advancement in recent years. The application of noncontrast helical computed tomography (CT) in patients with suspected ureteral colic is one major advance in the primary diagnostic process. The superior sensitivity and specificity of helical CT allow ureterolithiasis to be diagnosed without the potential side effects of contrast media. Initial management is based on three key concepts: (A) rational and fast diagnostic process (B) effective pain control (C) and understanding of the impact of stone location and size on the natural course of the disease and definitive urologic management. These concepts are discussed in this review with reference to contemporary literature.

Comparison of potassium-titanyl-phosphate laser vaporization of the prostate and transurethral resection of the prostate: update of a prospective non-randomized two-centre study

OBJECTIVES

To evaluate the intermediate-term clinical efficacy and the rate of complications in 80 W photoselective vaporization of the prostate (PVP) with the potassium-titanyl-phosphate laser (Greenlight, (AMS, Minnetonka, MN, USA) compared with transurethral resection of the prostate (TURP) in a prospective non-randomised two-centre study.

PATIENTS AND METHODS

From December 2003 to August 2006, 396 patients (PVP 269, TURP 127) with lower urinary tract symptoms secondary to benign prostatic hyperplasia were included in the study. There was a significant difference in mean age (72 years for PVP vs 68 for TURP, P = 0.001). Patients were therefore stratified in age categories (<70, 70-80, >80 years) and compared for perioperative variables, functional outcome and complications, with a follow-up of up to 24 months.

RESULTS

The mean prostate size was greater (overall, 62 vs 48 mL, P < 0.001) and mean operative duration longer (overall 72 vs 53 min; P = 0.001) for PVP in all age categories. The rate of intraoperative bleeding (3% vs 11%), blood transfusions (0% vs 5.5%) and capsule perforations (0.4% vs 6.3%), and early postoperative clot retention (0.4% vs 3.9%) was significantly lower for PVP. Hospitalization time was significantly shorter in the PVP group for patients aged <70 years (3.0 vs 4.7 days) and 70-80 years (4.0 vs 5.0 days; P = 0.001). The improvement of peak urinary flow rate was higher after TURP for any age category. The International Prostate Symptom Score and postvoid residual volume during the follow-up showed no significant difference. After 12 months the overall prostate size reduction was 63% (-30 mL) after TURP and 44% (-27 mL) after PVP. The rate of repeat TURP/PVP was higher in the PVP group (6.7% vs 3.9%, not significant) within the follow-up of up to 2 years. The incidence of urethral and bladder neck strictures was comparable.

CONCLUSIONS

PVP was more favourable in terms of perioperative safety. Although patients assigned for PVP were older and had larger prostates, PVP resulted in a similar functional outcome. Further follow-up is needed to draw final conclusions about the long-term efficacy of PVP.

[Benign space-occupying cysts in the testis. An overview]

Testicular cysts are increasingly diagnosed in the course of scrotal ultrasound examination. Among other things this is due to the general availability of modern high-resolution ultrasound devices. Benign and malignant diseases with testicular cyst formation need to be differentiated by differential diagnosis and by their aetiology. Benign diseases with cystic space-occupying lesions of the testicle are tubular ectasia of the rete testis, cystic dysplasia, epidermoid cysts, simple intraparenchymatous testicular cysts and cysts of the tunica albuginea. Testicular dermoid cyst was long misleadingly regarded as potentially malignant, but is now classified as benign. On diagnosis of a benign lesion of the testis an organ-conserving surgical therapy or an observational watch-and-wait strategy can be recommended in most cases.