HYbriD Resonant Acoustics (HYDRA).

The existence of what is termed here as a surface-reflected bulk wave is unraveled and elucidated, and it is shown, quite counterintuitively, that it is possible to obtain an order-of-magnitude improvement in microfluidic manipulation efficiency, and, in particular, nebulization, through a unique combination of surface and bulk waves without increasing complexity or cost.

Primary melioidotic prostatic abscess: presentation, diagnosis and management.

INTRODUCTION: In South-East Asia and Northern Australia, melioidosis (infection with Burkholderia pseudomallei) is a known cause of severe community-acquired sepsis. However, melioidosis presenting primarily as prostatic abscesses is very rare. METHODS: The presenting features, investigations and management outcome of five patients who developed melioidotic prostatic abscesses from 1997 to 2000 were reviewed in the present study. RESULTS: The mean age at presentation was 53 years (range: 29-69). Old age and diabetes mellitus were predisposing factors. All patients had a fever of at least 38.5 degrees C and presented with obstructive urinary symptoms culminating in urinary retention. Presence of prostatic abscess was demonstrated by transrectal ultrasound in all cases. The abscesses were drained with transurethral resection of the prostate. One patient required re-resection while another patient developed severe septic shock requiring intensive care and -inotropic support. There was no mortality in our series. CONCLUSIONS: Elderly diabetic men presenting with fever and urinary tract obstruction in endemic areas may harbour an unusual but potentially life threatening melioidotic prostatic abscess. Transrectal ultrasound and bacteriological confirmation are mandatory. Prompt surgical drainage coupled with appropriate antibiotics are keys to a favourable outcome.

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.

Giant mixed-type perinephric liposarcoma.

Retroperitoneal fatty tumours are uncommon occurrences in current urologic practice, the differentials being lipomas, liposarcomas and extra-renal angiomyolipomas (AML). We report an unusual case of a 48-year-old Chinese female who presented with a 6.2 kg giant mixed-type liposarcoma in the left perinephric space, invading into the renal cortex and parenchyma. Extirpative surgery with left radical nephrectomy was performed, and histology confirmed liposarcoma with both myxoid and well-differentiated elements. The patient remains well and disease-free at 6-month follow-up. We review the literature on the diagnosis and management of these perinephric lipomatous lesions. We also discuss the diagnostic dilemma in differentiating such malignancies from benign angiomyolipomas in the perinephric area on conventional radiological imaging, and its direct implications with respect to extent of surgery and renal preservation.

Loss of metal ions, disulfide reduction and mutations related to familial ALS promote formation of amyloid-like aggregates from superoxide dismutase.

Mutations in the gene encoding Cu-Zn superoxide dismutase (SOD1) are one of the causes of familial amyotrophic lateral sclerosis (FALS). Fibrillar inclusions containing SOD1 and SOD1 inclusions that bind the amyloid-specific dye thioflavin S have been found in neurons of transgenic mice expressing mutant SOD1. Therefore, the formation of amyloid fibrils from human SOD1 was investigated. When agitated at acidic pH in the presence of low concentrations of guanidine or acetonitrile, metalated SOD1 formed fibrillar material which bound both thioflavin T and Congo red and had circular dichroism and infrared spectra characteristic of amyloid. While metalated SOD1 did not form amyloid-like aggregates at neutral pH, either removing metals from SOD1 with its intramolecular disulfide bond intact or reducing the intramolecular disulfide bond of metalated SOD1 was sufficient to promote formation of these aggregates. SOD1 formed amyloid-like aggregates both with and without intermolecular disulfide bonds, depending on the incubation conditions, and a mutant SOD1 lacking free sulfhydryl groups (AS-SOD1) formed amyloid-like aggregates at neutral pH under reducing conditions. ALS mutations enhanced the ability of disulfide-reduced SOD1 to form amyloid-like aggregates, and apo-AS-SOD1 formed amyloid-like aggregates at pH 7 only when an ALS mutation was also present. These results indicate that some mutations related to ALS promote formation of amyloid-like aggregates by facilitating the loss of metals and/or by making the intramolecular disulfide bond more susceptible to reduction, thus allowing the conversion of SOD1 to a form that aggregates to form resembling amyloid. Furthermore, the occurrence of amyloid-like aggregates per se does not depend on forming intermolecular disulfide bonds, and multiple forms of such aggregates can be produced from SOD1.

A population study of nocturia in Singapore.

OBJECTIVE: To estimate the prevalence of nocturia in the multiracial Asian population of Singapore, using the new International Continence Society standardized definition of one or more voids per night, and to assess its associations, bothersomeness and impact on sleep. SUBJECTS AND METHODS: A door-to-door interview questionnaire survey was conducted amongst a randomly selected sample of 3000 individuals (response rate 78.2%). Nocturia and its associated problems were evaluated using questions from the International Prostate Symptom Score (IPSS), and concurrently, sociodemographic and health variables were recorded. RESULTS: Data from 1134 women (aged 20-95 years) and 1139 men (aged 20-92 years) were analysed; the overall prevalence of nocturia (one or more voids/night) was 55.5%, with an increasing proportion in older groups (P < 0.01). Women had nocturia significantly (P = 0.015) more often than men (58% vs 53%), and it was positively associated with poor health, with the highest odds ratios (95% confidence interval) for diabetes mellitus of 2.0 (1.3-3.1), for renal disease of 6.4 (2.3-18.2), and for strokes of 3.1 (1.1-9.2). In both men and women, the median IPSS in patients with nocturia was significantly higher than that in patients without nocturia (P < 0.001). For individuals waking once a night, only 9.5% considered nocturia a problem and 13.5% complained of sleep disturbances; these values increased to 36% and 40% for individuals waking up twice or more /night. CONCLUSION: Nocturia is a common condition amongst Singaporean adults, especially in the elderly; it has strong associations with poor health and other lower urinary tract symptoms. The degree of nocturia determines whether patients are likely to be bothered by it or have sleep disturbance, which will influence their help-seeking behaviour.

Laparoscopic drainage of nocardial adrenal abscess in an HIV positive patient.

We report a rare case of a nocardial adrenal abscess in an HIV patient that underwent the first drainage of adrenal abscess by laparoscopy. Adrenal abscesses are exceedingly rare in adults and prove to be a diagnostic challenge. Laparoscopic adrenal exploration is both a diagnostic and therapeutic modality with low perioperative morbidity that should be considered in the management of indeterminate adrenal masses and abscesses.

Predicting urinary stone composition using X-ray coherent scatter: a novel technique with potential clinical applications.

PURPOSE: Coherent scatter properties depend on the molecular structure of the scattering medium and measured scatter patterns are often characteristic of a chemical species. We explored the usefulness of coherent scatter analysis as a basis for identifying urinary calculus composition. MATERIALS AND METHODS: A laboratory system for collecting coherent scatter signals from biological specimens was developed. This technique uses a diagnostic x-ray tube and image intensifier, and measures coherent scatter from intact renal stones. The coherent scatter signatures of 6 common stone components (calcium oxalate monohydrate, calcium phosphate, calcium phosphate dihydrate, cystine, magnesium ammonium phosphate and uric acid) were acquired from pure chemical samples and stones identified by infrared spectroscopy as having a uniform composition. In addition, a sample of calculus identified as containing only calcium oxalate dihydrate was examined. The same fragmented stone samples analyzed by infrared spectroscopy were scanned using coherent scatter. RESULTS: In each case the scatter patterns from powdered chemicals and fragmented stones showed circular symmetry and consisted of a series of broad rings of various intensities. Each pure chemical sample produced a distinct coherent scatter pattern. The signatures of the stone specimens closely agreed with those of the chemical samples. CONCLUSIONS: These initial results indicate that coherent scatter analysis using diagnostic x-rays has potential as a tool for urinary calculous composition identification. Further developments in this technique may have the potential for determining the composition of a calculus in vivo before therapy, thus, aiding in therapy planning.