Weber Kam On Lau

A transition metal carbonyl probe for use in a highly specific and sensitive SERS-based assay for glucose.

A triosmium carbonyl cluster-boronic acid conjugate is used as a secondary carbohydrate probe in a SERS-based assay. The assay does not require conjugation of the metal carbonyl probe to a SERS-active species, and it utilizes the CO stretching vibrations of the metal carbonyl, which lies in a silent region of the SERS spectrum (1800-2200 cm(-1)), for quantification. High selectivity for glucose over fructose and galactose is obtained, and a human urine sample doped with glucose is detected accurately.

Optimal excitation-emission wavelengths for autofluorescence diagnosis of bladder tumors

Tissue autofluorescence depends on endogenous fluorophores in the tissue, which undergo a change associated with malignant transformation. This change can be detected as an alteration in the spectral profile and intensity of autofluorescence. Our purpose was to determine the optimal excitation and emission wavelengths for autofluorescence diagnosis of bladder cancer. A total of 52 bladder tissue specimens were obtained from 25 patients undergoing mucosal biopsies or surgical resections of bladder tumors. Light‐induced autofluorescence measurements were performed to study the spectroscopic differences between normal and malignant bladder tissue. Fluorescence excitation wavelengths varying from 220 to 500 nm were used to induce tissue autofluorescence, and emission spectra were measured in the 280–700 nm range. These spectra were then combined to construct 2‐dimensional fluorescence excitation‐emission matrices (EEMs). Significant changes in fluorescence intensity of EEMs were observed between normal and tumor bladder tissues, the most marked differences being at the excitation wavelengths of 280 and 330 nm. The diagnostic algorithm based on the combination of the fluorescence peak intensity ratios of I350/I470 at 280 nm excitation and I390/I470 at 330 nm excitation yielded a sensitivity of 100% [95% confidence interval (CI) 0.95–1.0] and specificity of 100% (95% CI 0.90–1.0). The results of the present fluorescence EEM study demonstrate that autofluorescence spectroscopy can distinguish malignant from normal bladder tissue and that excitation wavelengths of 280 and 330 nm are the most significant for differentiation between normal and malignant bladder mucosae with a high degree of diagnostic accuracy.

Is photodynamic diagnosis using hypericin better than white-light cystoscopy for detecting superficial bladder carcinoma?

To review the initial clinical results of photodynamic diagnosis (PDD) using hypericin (a new photosensitizer for PDD that helps to label flat urothelial tumours to facilitate biopsy) for the early detection of superficial bladder carcinoma, as flat noninvasive tumours of the bladder may be missed during conventional white‐light cystoscopy (WLC) if there is bladder overdistension or ongoing cystitis.

Sensitive SERS glucose sensing in biological media using alkyne functionalized boronic acid on planar substrates

In this work, we propose a novel glucose binding mechanism on a highly sensitive SERS substrate, in order to overcome challenges in specific glucose detection in bio-fluids. We make use of phenylboronic acid as a receptor for saccharide capture onto the substrate and the ability of the captured glucose molecule to undergo secondary binding with an alkyne-functionalized boronic acid to form a glucose-alkyne-boronic acid complex. The formation of this complex shows high selectivity for glucose, over other saccharides. In addition, the alkyne group of the alkyne-functionalized boronic acid exhibits a distinct Raman peak at 1996 cm(-1) in a biological silent region (1800-2800 cm(-1)) where most endogenous molecules, including glucose, show no Raman scattering, thus offering a high sensitivity over other SERS glucose sensing. The substrate offers long-term stability, as well as high SERS enhancement to the glucose-alkyne boronic acid complex on substrate. In addition, the reversibility of SERS signals at various incubation stages also shows reusability capabilities, whereas positive results in clinical urine samples demonstrate clinical feasibility. All these strongly suggest that this newly developed SERS-based assay offers great potential in glucose sensing.

Team-based approach reduces learning curve in robot-assisted laparoscopic radical prostatectomy.

Aim:  We assessed the team approach in reducing the learning curve during our 2‐year experience transiting from open to robot‐assisted laparoscopic radical prostatectomy (rLRP).

Early Experience with Robot-assisted Laparoscopic Radical Prostatectomy

INTRODUCTION We assessed the feasibility of a robot-assisted laparoscopic radical prostatectomy (rLRP) programme through a review of our early experience. PATIENTS AND METHODS Seventeen patients underwent rLRP between 1 February 2003 and 31 December 2003 at Singapore General Hospital. All patients had histologically confirmed adenocarcinoma on prostate biopsy and a negative bone scan. The Da Vinci robot was employed. The Montsouris technique was used for our first eight patients, and the Vattikuti Institute Prostatectomy technique was used for all subsequent patients. We studied perioperative parameters and early surgical outcome prospectively. RESULTS The mean age at diagnosis was 63.9 +/- 5.6 years. The median Gleason sum was 6 (range, 5-9), and mean pretreatment prostate-specific antigen level was 10.5 +/- 5.4 ng/mL. The mean set-up time was 34 +/- 18 minutes, and mean dissection time was 247 +/- 43 minutes. Perioperative blood loss averaged 494 +/- 330 mL, and three patients required blood transfusion. Normal diet was resumed after 1.7 +/- 0.6 days. The mean duration of bladder catheterization was 9.8 +/- 6.1 days, and mean hospital stay was 2.7 +/- 1.3 days. There was no perioperative mortality or major complications, and no conversion to open radical prostatectomy. From Case 9 onwards, there was significant reduction in operating time (284 vs 215 minutes), blood loss (650 vs 400 mL) and hospital stay (3.8 vs 1.8 days). CONCLUSIONS rLRP is feasible in a practice with a low volume of radical prostatectomies. Significant improvement in perioperative parameters occurs after the first eight cases. This technique confers the benefits of enhanced precision and dexterity for complex laparoscopic work in the pelvic cavity.

The Karakiewicz nomogram is the most useful clinical predictor for survival outcomes in patients with localized renal cell carcinoma

Outcomes after surgical removal of localized renal cell carcinoma (RCC) are variable. There have been multiple prognostic nomograms and risk groups developed for estimation of survival outcomes, with different models in use for evaluating patient eligibility in ongoing trials of adjuvant therapy. The authors aimed to establish the most useful prognostic model for patients with localized RCC to guide trial design, biomarker research, and clinical counseling.

Robotic ultrasound-guided prostate intervention device: system description and results from phantom studies.

We introduce the first robotic ultrasound‐guided prostate intervention device and evaluate its safety, accuracy and repeatability.

The potential application of chlorin e6–polyvinylpyrrolidone formulation in photodynamic therapy

Much research has been focused on developing effective drug delivery systems for the preparation of chlorins as potential photosensitizers for PDT. This report describes the evaluation of a new water-soluble formulation of chlorin e6 consisting of a complex of trisodium salt chlorin e6 and polyvinylpyrrolidone (Ce6-PVP) for application in photodynamic therapy (PDT) with 2 specific aims: (i) to investigate its fluorescence kinetics in skin, normal and tumor tissue after intravenous administration, and (ii) to investigate its PDT efficacy. Our results demonstrate that this new formulation possesses photosensitizing properties with rapid accumulation in tumor tissue observed within 1 h after intravenous administration. Although high selectivity in tumor tissue was found between the period of 3 and 6 h, the efficacy of Ce6-PVP mediated PDT was best at 1 h drug-light interval. It is suggested that, the extent of tumor necrosis post PDT is dependent on the plasma concentration of Ce6-PVP, implying a vascular mediated cell death mechanism. A faster clearance rate of Ce6-PVP from the skin of nude mice was observed compared to Ce6. The new formulation of Ce6-PVP seems to show promise as an effective therapeutic agent.

New Frontier in Hypericin-Mediated Diagnosis of Cancer with Current Optical Technologies

Photosensitizers (PSs) have shown great potentials as molecular contrast agents in photodynamic diagnosis (PDD) of cancer. While the diagnostic values of PSs have been proven previously, little efforts have been put into developing optical imaging and diagnostic algorithms. In this article, we review the recent development of optical probes that have been used in conjunction with a potent PS, hypericin (HY). Various fluorescence techniques such as laser confocal microscopy, fluorescence urine cytology, endoscopy and endomicroscopy are covered. We will also discuss about image processing and classification approaches employed for accurate PDD. We anticipate that continual efforts in these developments could lead to an objective PDD and complete surgical clearance of tumors. Recent advancements in nanotechnology have also opened new horizons for PSs. The use of biocompatible gold nanoparticles as carrier for enhanced targeted delivery of HY has been attained. In addition, plasmonic properties of nanoparticles were harnessed to induce localized hyperthermia and to manage the release of PS molecules, enabling a better therapeutic outcome of a combined photodynamic and photothermal therapy. Finally, we discuss how nanoparticles can be used as contrast agents for other optical techniques such as optical coherence tomography and surface-enhanced Raman scattering imaging.