Pathological outcome for Chinese patients with low-risk prostate cancer eligible for active surveillance and undergoing radical prostatectomy: comparison of six different active surveillance protocols.

INTRODUCTION: Active surveillance is one of the therapeutic options for the management of patients with low-risk prostate cancer. This study compared the performance of six different active surveillance protocols for prostate cancer in the Chinese population. METHODS: Patients who underwent radical prostatectomy for prostate cancer from January 1998 to December 2012 at a university teaching hospital in Hong Kong were reviewed. Six active surveillance protocols were applied to the cohort. Statistical analyses were performed to compare the probabilities of missing unfavourable pathological outcome. The sensitivity and specificity of each protocol in identifying low-risk disease were compared. RESULTS: During the study period, 287 patients were included in the cohort. Depending on different active surveillance protocols used, extracapsular extension, seminal vesicle invasion, pathological T3 disease, and upgrading of Gleason score were present on final pathology in 3.3%-17.1%, 0%-3.3%, 3.3%-19.1%, and 20.6%-34.5% of the patients, respectively. The University of Toronto protocol had a higher rate of extracapsular extension at 17.1% and pathological T3 disease at 19.1% on final pathology than the more stringent protocols from John Hopkins (3.3% extracapsular extension, P=0.05 and 3.3% pathological T3 disease, P=0.03) and Prostate Cancer Research International: Active Surveillance (PRIAS; 8.0% pathological T3 disease, P=0.04). The Royal Marsden protocol had a higher rate of upgrading of Gleason score at 34.5% compared with the more stringent protocol of PRIAS at 20.6% (P=0.04). The specificities in identifying localised disease and low-risk histology among different active surveillance protocols were 59%-98% and 58%-94%, respectively. The John Hopkins active surveillance protocol had the highest specificity in both selecting localised disease (98%) and low-risk histology (94%). CONCLUSIONS: Active surveillance protocols based on prostate-specific antigen and Gleason score alone or including Gleason score of 3+4 may miss high-risk disease and should be used cautiously. The John Hopkins and PRIAS protocols are highly specific in identifying localised disease and low-risk histology.

Partial nephrectomy for T1 renal cancer can achieve an equivalent oncological outcome to radical nephrectomy with better renal preservation: the way to go.

INTRODUCTION: Patients who undergo partial nephrectomy have been shown to be at decreased risk of renal impairment compared with radical nephrectomy. We examined the oncological outcome of patients in our centre who underwent partial or radical nephrectomy for T1 renal cancer (7 cm or smaller), and compared the likelihood of developing chronic kidney disease. METHODS: This historical cohort study with internal comparison was conducted in a tertiary hospital in Hong Kong. A cohort of 86 patients with solitary T1 renal cancer and a normal contralateral kidney who underwent radical (38 patients) or partial (48 patients) nephrectomy between January 2005 and December 2010 was included. The overall and cancer-free survival, change in glomerular filtration rate, and new onset of chronic kidney disease were compared between the radical and partial nephrectomy groups. RESULTS: A total of 32 (84%) radical nephrectomy patients and 43 (90%) partial nephrectomy patients were alive by 31 December 2012. The mean follow-up was 43.5 (standard deviation, 22.4) months. There was no significant difference in overall survival (P=0.29) or cancer-free survival (P=0.29) between the two groups. Both groups enjoyed good oncological outcome with no recurrence in the partial nephrectomy group. Overall, 18 (21%) patients had pre-existing chronic kidney disease. The partial nephrectomy group had a significantly smaller median reduction in glomerular filtration rate (12.6% vs 35.4%; P<0.001), and radical nephrectomy carried a significantly higher risk of developing chronic kidney disease (hazard ratio=5.44; 95% confidence interval, 1.26-23.55; P=0.02). CONCLUSIONS: Compared with radical nephrectomy, partial nephrectomy can prevent chronic kidney disease and still achieve an excellent oncological outcome for T1 renal tumours, in particular T1a tumours and tumours with a low R.E.N.A.L. score.

Initial results of selective renal parenchymal clamping with an adjustable kidney clamp in nephron-sparing surgery: an easy way to minimise renal ischaemia.

INTRODUCTION: A renal parenchymal clamp has been used at our centre since March 2012. It is used in position over the kidney to achieve optimal vascular control of a tumour while minimising parenchymal ischaemia. This study aimed to report the feasibility, surgical outcome, and oncological control of a kidney clamp in partial nephrectomy. METHODS: This study was conducted at a teaching hospital in Hong Kong. Partial nephrectomies performed from January 2009 to March 2015 were reviewed. The tumour characteristics and surgical outcomes of kidney clamp were studied and compared with traditional hilar clamping. RESULTS: A total of 92 patients were identified during the study period. Kidney clamps were used in 20 patients and hilar clamping in 72, with a mean follow-up of 27 and 37 months, respectively. For patients in whom a kidney clamp was applied, all tumours were exophytic to a different extent and the majority (90%) were located at the polar region. The PADUA (preoperative aspects and dimensions used for an anatomical) classification nephrometry score was also lower than those in whom hilar clamping was used (7.07 vs 8.34; P=0.002). The clamp was used in open, laparoscopic, and robot-assisted surgery. Operating time was shorter (207 ± 72 mins vs 306 ± 80 mins; P<0.001) and estimated blood loss was lower (205 ± 191 mL vs 331 ± 275 mL; P=0.045) with kidney clamp. No acute kidney injury occurred. Postoperative renal function was comparable between the two groups. CONCLUSIONS: Partial nephrectomy using parenchymal clamping is safe and feasible in selected cases. The postoperative renal function and oncological control were satisfactory.

Impact of skeletal-related events on survival in patients with metastatic prostate cancer prescribed androgen deprivation therapy.

OBJECTIVE: To investigate the impact of skeletal-related events on survival in patients with metastatic prostate cancer prescribed long-term androgen deprivation therapy. METHODS: This historical cohort study was conducted in two hospitals in Hong Kong. Patients who were diagnosed with metastatic prostate cancer and prescribed androgen deprivation therapy between January 2006 and December 2011 were included. Details of skeletal-related events and mortality were examined. RESULTS: The median follow-up was 28 (range, 1-97) months. Of 119 patients, 52 (43.7%) developed skeletal-related events throughout the study, and the majority received bone irradiation for pain control. The median actuarial overall survival and cancer-specific survival for patients with skeletal-related events were significantly shorter than those without skeletal-related events (23 vs 48 months, P=0.003 and 26 vs 97 months, P<0.001, respectively). Multivariate analysis revealed that the adjusted hazard ratio of presence of skeletal-related events on overall and cancer-specific survival was 2.73 (95% confidence interval, 1.46-5.10; P=0.002) and 3.92 (95% confidence interval, 1.87-8.23; P<0.001), respectively. A prostate-specific antigen nadir of >4 ng/mL was an independent poor prognostic factor for overall and cancer-specific survival after development of skeletal-related events (hazard ratio=10.42; 95% confidence interval, 2.10-51.66 and hazard ratio=10.54; 95% confidence interval, 1.94-57.28, respectively). CONCLUSIONS: Skeletal-related events were common in men with metastatic prostate cancer. This is the first reported study to show that a skeletal-related event is an independent prognostic factor in overall and cancer-specific survival in patients with metastatic prostate cancer prescribed androgen deprivation therapy. A prostate-specific antigen nadir of >4 ng/mL is an independent poor prognostic factor for overall and cancer-specific survival following development of skeletal-related events.

Peritoneal implantation of ureter in cadaveric renal transplant.

We report here a case of complication of peritoneal implantation of ureter in cadaveric renal transplant. The patient presented with anuria and delayed graft function. The diagnosis was suspected upon physical examination and radiological investigation. The complication was managed with reimplantation of the ureter into the bladder and the patient recovered with good graft function. We discuss this case, review the literature on this rare complication, and share our suggestions on how it can be prevented.

The Chinese version of the pelvic pain and urgency/frequency symptom scale: a useful assessment tool for street-ketamine abusers with lower urinary tract symptoms.

OBJECTIVE: To investigate the use of a translated Chinese version of the pelvic pain and urgency/frequency symptom scale as an assessment and prognostic tool to evaluate the severity of street-ketamine-associated lower urinary tract symptoms and their reversibility after abstinence. DESIGN: Cross-sectional study. SETTING: A special designated out-patient clinic in a regional hospital in Hong Kong. PARTICIPANTS: There were 50 patients with street-ketamine-associated lower urinary tract symptoms and 20 healthy individuals. MAIN OUTCOME MEASURES: Reliability and validity of the questionnaire; frequency of individual lower urinary tract symptoms, cystoscopic, urodynamic and radiological abnormalities, and their correlation with pelvic pain and the urgency/frequency score. RESULTS: The test-retest reliability coefficient was 0.755 (P<0.001). Cronbach's alpha was 0.974. Mann-Whitney U test proved the discriminatory ability of the questionnaire (P<0.001). Patients with specific lower urinary tract symptoms had a higher mean pelvic pain and urgency/frequency total score compared to those without them: frequency (23.8 vs 17.3), nocturia (22.4 vs 14.0), urgency (22.5 vs 15.1), dysuria (22.7 vs 13.3), and haematuria (24.8 vs 16.2). The number of daytime voids and nocturia episodes correlated well with pelvic pain and urgency/frequency scores. With an increasing score, the likelihood of having cystitis changes, urodynamic abnormalities and hydronephrosis increased, while the cystometrically determined bladder capacity decreased. None of the patients with a score of 16 or below had urodynamic abnormality or hydronephrosis. The mean score change in the abstinence group was -4.33, versus +3.33 in their counterparts. CONCLUSIONS: The Chinese version of the pelvic pain and urgency/frequency questionnaire is reliable and valid for assessment in patients with street-ketamine-associated lower urinary tract symptoms. The pelvic pain and urgency/frequency score correlates well with symptom severity as well as endoscopic, urodynamic and radiological abnormalities in patients with street-ketamine-associated lower urinary tract symptoms. A cut-off total pelvic pain and urgency/frequency score of 17 may suggest more serious urological sequelae from ketamine abuse. Abstinence from ketamine reduced lower urinary tract symptoms, but the extent of reversibility of urinary tract damage is yet to be evaluated.

A new direct compression mechanism of structural transition in Poria cocos extract composite particles.

The structural transition to generate amorphous translucent grains in Poria cocos dry extract (PCE) composite particles was found and studied as a new direct compression mechanism. The pressure and displacement sensing techniques were used to obtained stress-strain profiles during compression. The Exponential function, Kawakita model, Shapiro model and Heckel model were used to analysis mechanical properties of powders. 12 parameters derived from compression models and powder physical properties were applied to partial least squares method (PLS) for analyzing powder compression mechanism. It was found that only the oven-dried PCE composite particles undergoes the structural transition and generate translucent grains scattered and embedded in tablet, and these tablets have excellent mechanical stability. The structural transition in plant dry extract as the PCE composite particles could be exploited to improve powder compression and tabletability.

Soil formate regulates the fungal nitrous oxide emission pathway.

Fungal activity is a major driver in the global nitrogen cycle, and mounting evidence suggests that fungal denitrification activity contributes significantly to soil emissions of the greenhouse gas nitrous oxide (N(2)O). The metabolic pathway and oxygen requirement for fungal denitrification are different from those for bacterial denitrification. We hypothesized that the soil N(2)O emission from fungi is formate and O(2) dependent and that land use and landforms could influence the proportion of N(2)O coming from fungi. Using substrate-induced respiration inhibition under anaerobic and aerobic conditions in combination with (15)N gas analysis, we found that formate and hypoxia (versus anaerobiosis) were essential for the fungal reduction of (15)N-labeled nitrate to (15)N(2)O. As much as 65% of soil-emitted N(2)O was attributable to fungi; however, this was found only in soils from water-accumulating landforms. From these results, we hypothesize that plant root exudates could affect N(2)O production from fungi via the proposed formate-dependent pathway.

Bryan artificial cervical disc arthroplasty in a patient with Klippel-Feil syndrome.

Technological advances have made more options available for surgical intervention in spinal disorders. From spinal fusion to artificial disc implantation, these advancements have brought great benefits, allowing preservation of spinal motion and flexibility after intervertebral discectomy. Yet the use of artificial discs as a treatment for congenital spinal disorders has been documented in only a handful of publications. We report a case where a Bryan artificial cervical disc arthroplasty was used to maintain and preserve the mobility and function of the cervical motion segments adjacent to fused vertebral lesions in a 33-year-old woman with Klippel-Feil syndrome who presented with chronic neck pain and signs of early myelopathy. The rationales for using the Bryan disc prosthesis system in patients with Klippel-Feil syndrome and its advantages over conventional surgical interventions are discussed.

'Street ketamine'-associated bladder dysfunction: a report of ten cases.

Ten young ketamine abusers presented with lower urinary tract symptoms to two regional hospitals in Hong Kong. Investigations demonstrated contracted bladders and other urinary tract abnormalities. These types of findings have never been reported before in ketamine abusers. The possible aetiology is also discussed.

Anterior perineal hernia after anterior exenteration.

Perineal hernia is a rare complication of anterior exenteration. We reported this complication after an anterior exenteration for bladder cancer with bleeding complication requiring packing and second-look laparotomy. Perineal approach is a simple and effective method for repair of perineal hernia.

What is the minimum amount of simulated breast movement required for visual detection of blurring? An exploratory investigation.

OBJECTIVE: Image blurring in mammography can cause significant image degradation and interpretational problems. A potential source is due to paddle movement during image formation. Paddle movement has been shown to be as much as 1.5 mm. No study has yet been performed to determine how much motion would be noticeable visually. The aim of this study is to determine the minimum amount of simulated breast movement at which blurring can be detected visually. METHODS: 25 artefact-free mammogram images were selected. Mathematical simulation software was created to mimic the effect of blurring produced by breast movement during exposure. Motion simulation was imposed to 15 levels, from 0.1 to 1.5 mm stepping through 0.1 mm increments. 15 degraded images and 1 without blurring were de-identified, randomized and assessed on a blinded basis by two clinical experts to determine the presence or absence of blurring. Statistical testing was carried out to determine the consistency between the two observers. RESULTS: The probability of simulated blurred image detection is the highest for the gaussian method and the lowest for soft-edged mask estimation. CONCLUSION: The amount of simulated breast movement at which blurring can be detected visually for gaussian blur, hard-edge mask estimation and soft-edge mask estimation is 0.4, 0.8 and 0.7 mm, respectively. Cohen's kappa for all the levels of simulated blurring is 0.689 (p < 0.05). ADVANCES IN KNOWLEDGE: This research establishes the concept of using probability to represent visual detection of blurring rather than defining a hard cut-off level.

Combination of ofloxacin and amikacin in the treatment of sternotomy wound infection.

Mycobacterium fortuitum infection of soft tissue and wound (postoperative or otherwise) has been well reported in medical literature. In 1987, ten patients in our hospital with various cardiac diagnoses requiring open-heart surgery developed M fortuitum infection at the sternotomy site. As successful chemotherapy, in addition to surgical debridement, relies on in vitro susceptibility testing, ofloxacin and amikacin were thus assessed and found to have very satisfactory MIC. For the former: 1.25 mg/L for eight isolates, 2.5 mg/L for one isolate, and greater than 20 mg/L for one isolate were found. For the latter: 1 mg/L for six isolates, 2 mg/L for two isolates, and 4 mg/L and 8 mg/L for the remaining two isolates were found, respectively. These patients were given ofloxacin (300 mg once daily to 1,200 mg daily in divided doses) for three to six months and 500 mg amikacin daily (in two divided doses intravenously or intramuscularly) for three to eight weeks. The clinical outcome was favorable except for one patient who died of bacteremia due to M fortuitum coupled with many medical complications. Encouraged by these preliminary results, a future prospective study with ofloxacin as single agent for soft tissue, particularly postoperative sepsis due to M fortuitum, will be planned.

Single daily-dose ofloxacin monotherapy for Mycobacterium fortuitum sternotomy infection.

Infection of sternotomy wounds due to Mycobacterium fortuitum-chelonei complex postoperatively was noted in ten patients in 1987 and six patients in 1988 in our hospital. The first ten patients were treated with a combination of ofloxacin and amikacin, successfully in nine. In the six later patients, five had M fortuitum infection and one had M chelonei infection. In those five we used single daily-dose ofloxacin, 600 mg, in three with rapid clinical response and bacteriologic cure. The MIC of ofloxacin for these three isolates ranged from 0.32 mg/L to 1.25 mg/L, and peak serum level of ofloxacin assessed by high-performance liquid chromatography ranged from 4.1 mg/L to 8.0 mg/L. Monotherapy with ofloxacin is recommended for M fortuitum infection of wound and soft tissue, with in vitro susceptibility studies as a guide, pending further reinforcing clinical evidence.

Antimicrobial activity of ofloxacin and other agents against mycobacterial isolates from postoperative sternotomy wounds.

In 1987 and 1988, 16 patients in a cardiothoracic hospital developed median sternotomy wound infections from Mycobacterium fortuitum or Mycobacterium chelonei (M fortuitum, 14 patients; M chelonei, two patients). For M fortuitum isolates, the minimum inhibitory concentration (MIC) (by agar dilution) of ofloxacin was 0.32 to 1.25 mg/L; of amikacin, 0.5 to 1 mg/L; of sulfadiazine, 16 to 256 mg/L; of imipenem, less than or equal to 2 to 4 mg/L; of cefoxitin, 4 to 16 mg/L; of ampicillin, 64 to greater than 256 mg/L; of cephapirin, 64 to 128 mg/L; of cefoperazone, greater than 256 mg/L; and of ceftazidime, greater than 256 mg/L. Addition of sulbactam to ampicillin and cefoperazone resulted in at least a four- to eight-fold reduction of their respective MICs. For M chelonei isolates, the MIC of ofloxacin was greater than 20 mg/L; of amikacin, 8 mg/L; of sulfadiazine, 64 mg/L; of imipenem, 8 mg/L; of cefoxitin, 16 mg/L; of ampicillin, 128 mg/L; of cephapirin, 128 mg/L; of cefoperazone, greater than 256 mg/L; and of ceftazidime, greater than 256 mg/L. Addition of sulbactam resulted in much smaller reductions of the MICs of ampicillin and cefoperazone. Synergism was noticed between ofloxacin and amikacin against M chelonei but not against M fortuitum. The results indicate that ofloxacin alone is as effective as the combination of ofloxacin and amikacin in treating M fortuitum, but not M chelonei, infection.

Estimation of distortion product otoacoustic emissions.

Distortion product otoacoustic emissions (DPOAE's) are acoustic signals generated from the cochlea when stimulated by dual tone stimulus. The measurement of the DPOAE's is useful in objectively assessing the hearing functionality of humans. The parameter estimation of the DPOAE's has been based on the fast Fourier transform (FFT) technique, which may not guarantee optimum performance in general. In this paper, we investigate the optimal maximum-likelihood estimator (MLE) for the DPOAE's. Experiments showed that the performance of the MLE is superior to those of the conventional FFT estimators. Furthermore, it is proven that the unwindowed FFT estimator is essentially the MLE when the stimulus tones are constrained to exhibit complete cycle within the data frame.

A fast recursive-least-squares adaptive notch filter and its applications to biomedical signals.

A fast recursive-least-squares (FRLS) adaptive notch filter (ANF) for cancellation of sinusoidal interference from recorded biomedical signals is investigated. The FRLS ANF is derived by making an approximation to the conventional recursive-least-squares (RLS) ANF for computation economy. It outperforms the commonly adopted least-mean-squares (LMS) ANF, demonstrating a rapid and bandwidth-insensitive initial convergence. A novel application of the FRLS ANF is for the elimination of the tonal artefact in distortion product otoacoustic emission (DPOAE) signals.

Extra patient movement during mammographic imaging: an experimental study.

OBJECTIVE: To determine if movement external to the patient occurring during mammography may be a source of image blur. METHODS: Four mammography machines with eight flexible and eight fixed paddles were evaluated. In the first stage, movement at the paddle was measured mechanically using two calibrated linear potentiometers. A deformable breast phantom was used to mimic a female breast. For each paddle, the movement in millimetres and change in compression force in Newton was recorded at 0.5- and 1-s intervals, respectively, for 40 s with the phantom in an initially compressed state under a load of 80 N. In the second stage, clinical audit on 28 females was conducted on one mammography machine with the 18 × 24- and 24 × 29-cm flexible paddles. RESULTS: Movement at the paddle followed an exponential decay with a settling period of approximately 40 s. The compression force readings for both fixed and flexible paddles decreased exponentially with time, while fixed paddles had a larger drop in compression force than did flexible paddles. There is a linear relationship between movement at the paddle and change in compression force. CONCLUSION: Movement measured at the paddle during an exposure can be represented by a second order system. The amount of extra patient movement during the actual exposure can be estimated using the linear relationship between movement at the paddle and the change in compression force. ADVANCES IN KNOWLEDGE: This research provides a possible explanation to mammography image blurring caused by extra patient movement and proposes a theoretical model to analyse the movement.