Wen Horng Yang

Gas-Forming Infection of the Urinary Tract: An Investigation of Fermentation As a Mechanism

Most gas-forming infections occur in patients with diabetes. Carbon dioxide formation, resulting from fermentation of the high concentration of sugar in the urine and tissue by infecting organisms, was regarded as the key factor of gas formation in previous reports. Gas from an emphysematous infection of a polycystic kidney was analyzed to understand better the mechanisms involved in gas-forming infections of the urinary tract. The term emphysematous renal polycystic infection is proposed for this particular condition. Gas from the cysts contained 4.1% carbon dioxide, 10.5% oxygen, 67.3% nitrogen and 18.1% unknown gas. This finding is astonishingly similar to that of Wheeler in 1954 and cannot be fully explained by the sugar fermentation theory. Therefore, we propose a new hypothesis. Impaired transportation of gas produced by rapid catabolism leads to gas accumulation in the tissue, which will gradually expand and create chambers to form gas bubbles. Gas of adjacent tissues will attempt to come into equilibrium with the gas bubbles. Positive equilibrium will lead to continuous expansion of the lesion bubble. However, if the chamber is unable to withstand the increasing pressure then rupture or spontaneous drainage of the gas bubble may occur. During negative equilibrium gas in the bubble gradually simulates tissue gas with eventual shrinkage of the bubble. If the chamber is unable to sustain the pressure it collapses and the bubble disappears. However, if the chamber is capable of sustaining the pressure the bubble still may persist even when the gas content is equivalent to tissue gas. This hypothesis may lead to better understanding of emphysematous infections of the urinary tract and also may cast light on emphysematous infections of other organ systems.

Transitional Cell Carcinoma in Dialysis Patients

Objective: The aim of our study was to determine whether there is an increased incidence of urothelial cancer, especially transitional cell carcinoma (TCC), in uremic patients on dialysis.Methods: Retrospective chart analyses were completed for 1,910 uremic patients undergoing maintenance dialysis between January 1987 and December 1997. The incidence of urinary tract cancer was assessed. Only the patients with cancers diagnosed after start of dialysis were enrolled in the study.Results: Of the 1,910 patients, 70 had concomitant urinary tract cancers. Nineteen patients (0.99%), including 17 patients with TCC and 2 patients with renal cell carcinoma, were diagnosed after the initiation of dialysis. The average duration from dialysis to TCC diagnosis was 38.3 (range 2–144) months. Painless gross hematuria was the cardinal symptom in 16 of the 17 patients with TCC. In the 17 patients with TCC, no distant metastases were found at the time of diagnosis. Fourteen patients (82.3%) were stage 0 or A, and 1 patient was stage B1.Conclusions: The 0.89% incidence of TCC in our dialysis patients was high as compared with that of the general population. The risks of developing urinary TCC in dialysis patients were examined, and we suggest that immunosuppressive stage, dialysis procedure, and chronic bladder irritation (decreased urinary wash effect) may play a part in the development of urinary TCC in dialysis patients. Early detection of hematuria due to regular visits and decreased exposure of urinary tract epithelium to carcinogens from urine may explain why early–stage TCC was seen in most of our patients.

Screening of Antibiotic Susceptibility to β-Lactam-Induced Elongation of Gram-Negative Bacteria Based on Dielectrophoresis

We demonstrate a rapid antibiotic susceptibility test (AST) based on the changes in dielectrophoretic (DEP) behaviors related to the β-lactam-induced elongation of Gram-negative bacteria (GNB) on a quadruple electrode array (QEA). The minimum inhibitory concentration (MIC) can be determined within 2 h by observing the changes in the positive-DEP frequency (pdf) and cell length of GNB under the cefazolin (CEZ) treatment. Escherichia coli and Klebsiella pneumoniae and the CEZ are used as the sample bacteria and antibiotic respectively. The bacteria became filamentous due to the inhibition of cell wall synthesis and cell division and cell lysis occurred for the higher antibiotic dose. According to the results, the pdfs of wild type bacteria decrease to hundreds of kHz and the cell length is more than 10 μm when the bacterial growth is inhibited by the CEZ treatment. In addition, the growth of wild type bacteria and drug resistant bacteria differ significantly. There is an obvious decrease in the number of wild type bacteria but not in the number of drug resistant bacteria. Thus, the drug resistance of GNB to β-lactam antibiotics can be rapidly assessed. Furthermore, the MIC determined using dielectrophoresis-based AST (d-AST) was consistent with the results of the broth dilution method. Utilizing this approach could reduce the time needed for bacteria growth from days to hours, help physicians to administer appropriate antibiotic dosages, and reduce the possibility of the occurrence of multidrug resistant (MDR) bacteria.

Antibiotic susceptibility test based on the dielectrophoretic behavior of elongated Escherichia coli with cephalexin treatment.

This study reports the use of dielectrophoresis (DEP), which determined the crossover frequency (cof) of antibiotic-induced elongation of Escherichia coli (E. coli) with regard to the rapid antibiotic susceptibility test (AST). Different dielectric properties and elongation rates of E. coli are caused by various concentrations of cephalexin treatment. According to the authors results, significant changes in the cof of bacteria treated with 32 μg∕ml antibiotic for 60 min can be found by using a quadruple electrode array, and the results of DEP-based AST correspond with that of agar dilution method. Utilizing this approach could greatly reduce the period of bacteria growth, and obtain the minimum inhibition concentration of E. coli to cephalexin.

Transurethral microwave thermotherapy for symptomatic benign prostatic hyperplasia: Long-term durability with Prostcare

Objective: To evaluate the long–term durability of transurethral microwave thermotherapy (TUMT) with Prostcare for symptomatic benign prostatic hyperplasia (BPH). Patients and Methods: From August 1993 to July 1994, a total of 65 patients with symptomatic BPH who underwent TUMT using the Prostcare apparatus (Bruker Spectospin, Wissembourg, France) with low–energy protocol (maximal power 52 W) were enrolled into a short–term evaluation. Subsequent follow–up information was collected in July 1999. If patients had had any further therapy for BPH, the date of retreatment was considered as an endpoint of TUMT efficacy. If no further therapy for BPH had been needed, they were re–assessed for overall satisfaction. Results: The median follow–up period was 49 months. Twenty patients were excluded for various reasons, including 17 with loss of follow–up and 3 with new diseases that could affect the voiding status. Thirty–eight (84.4%) of 45 valuable patients had received further therapy for BPH, including medication (n = 21, 46.7%), and endoscopic surgery (n = 17, 37.7%). The times to pharmacologic or endoscopic retreatment after TUMT were 8.9±11.1 and 23.0±14.4 months, respectively (p = 0.0003, log rank test). Only 7 (15.5%) patients had no further treatment, with 3 having satisfactory improvements, but 4 feel dissatisfied yet not needing any further therapy. In addition, 2 patients complained of erectile dysfunction after TUMT and 1 was diagnosed with prostate cancer 50 months after TUMT. In addition, there was no significant difference for all baseline values among three groups with no retreatment or retreatment with medication or endoscopic surgery. Conclusion: At the 5–year follow–up, the long–term durability of low–energy TUMT with Prostcare is only exhibited in a few patients and the overall retreatment rate was 84.4%. Thus, patient should be informed of the high probability of supplementary treatment after TUMT.

Prognostic Values of p53 and HER-2/neu Coexpression in Invasive Bladder Cancer in Taiwan

Objectives: To explore the clinical significance of p53 and HER-2/neu coexpression by immunohistochemistry in patients with invasive bladder cancer in Taiwan. Methods: Paraffin-embedded tumor blocks were obtained from 67 patients with invasive bladder cancer subjected to radical cystectomy, bilateral lymph node dissection, and urinary diversion with or without systemic chemotherapy. Two observers (N.H.C. and T.S.T.), blinded to clinical outcome, reviewed the immunohistochemical staining for p53 (PAb1801) and HER-2/neu (Ab-17). The results were analyzed for progression-free survival and patient survival. Results: Positive staining for p53 and HER-2/neu was found in 30 (44.8%) and 39 (58.2%) patients. In contrast to HER-2/neu, p53 expression was significantly associated with tumor grade and pathologic stage (p = 0.040 and 0.004, respectively), and tended to be related to the nodal status (p = 0.080). Most importantly, coexpression of p53 and HER-2/neu significantly correlated with nodal metastases (p = 0.020). Univariate and multivariate analysis revealed p53 and nodal status as two independent prognostic factors. Additionally, patients with p53 and HER-2/neu coexpression had the shortest time to relapse and overall survival, irrespective of whether adjuvant chemotherapy was given or not (p = 0.005 and 0.030). Conclusions: In invasive bladder cancer, p53 was an important prognostic factor since its expression correlated with tumor grade and stage, even nodal status, whereas HER-2/neu did not show prognostic significance. Tumors with p53 and HER-2/neu coexpression were associated with nodal metastases, probably resulting in decreased progression-free survival. Although some basic studies provide some important supports, studies including larger patient cohorts would still be required to prove the hypothesis that p53 and HER-2/neu-coexpressing tumors have a worse prognosis and are more resistant to a cisplatin-based multidrug regimen.

Acute urinary retention increases the risk of complications after transurethral resection of the prostate: a population-based study.

Study Type – Prognosis (cohort)

In Vitro Study of Ultrasound Based Real-Time Tracking for Renal Stones in Shock Wave Lithotripsy: Part II—A Simulated Animal Experiment

PURPOSEnWe have previously developed and reported an ultrasound based real-time tracking system for renal stones. In the current study we continued to verify the reliability of this tracking system by a simulated animal test.nnnMATERIALS AND METHODSnWe used 13 prerecorded ultrasound stone trajectories to test the system. The real-time tracking system was implemented on the Litemed 9200 electrohydraulic lithotriptor (LiteMed Co., Taipei, Taiwan). An artificial stone and tap water were sealed in a balloon. The balloon was inserted into the pelvis of a pig kidney. While the kidney was affixed to and moved by a simulator, it was immersed in a specifically designed simulated animal model tank containing tap water. The stone was localized by ultrasound. The kidney was moved by the simulator according to a prerecorded stone trajectory. A total of 3,000 shock waves were delivered to the stone. For each recorded stone trajectory experiments were done under nontracking and tracking conditions. We performed tests of the fragment-to-weight ratio, which denotes the performance of a shock wave lithotriptor when fragmenting a stone.nnnRESULTSnThe mean fragment-to-weight ratio was 55.3% +/- 25.9% in the nontracking and 100% +/- 0% in the tracking group. The difference in these 2 groups was statistically significant (paired t test p <0.01).nnnCONCLUSIONSnThe ultrasound based real-time tracking system proved to improve the performance of a shock wave lithotriptor significantly when fragmenting stones in a simulated animal test. We believe that the tracking system would greatly reduce the number of shocks and time needed for treating renal stones.

Clinical Characteristics and Reproductive Outcomes in Infertile Men With Testicular Early and Late Maturation Arrest

OBJECTIVEnTo compare the clinical characteristics and reproductive outcomes of nonobstructive azoospermic men with uniform early and late maturation arrest.nnnMETHODSnPatients with biopsy-documented uniform maturation arrest undergoing testicular sperm retrieval and complete medical records were enrolled in the present study. Their medical history, physical examination findings, testicular volume, serum hormone parameters, genetic anomalies, sperm retrieval, and reproductive outcomes were retrospectively analyzed.nnnRESULTSnIn a cohort of 223 nonobstructive azoospermic men, 34 men with uniform maturation arrest (21 early maturation arrest and 13 late maturation arrest) were identified. No significant differences were seen in the age distribution, testicular volume, or hormone parameters between patients with early and late maturation arrest. Only 13 patients (38.2%) had a normal serum follicle-stimulating hormone level and normal testicular volume. Patients with early maturation arrest had a greater frequency of overall genetic anomalies, and patients with late maturation arrest had a greater frequency of previous testicular insults. The sperm retrieval and impregnation rate were nonsignificantly greater in patients with late maturation arrest.nnnCONCLUSIONnMaturation arrest has a variety of causes and presents with diverse phenotypes. Not all patients with uniform maturation arrest have a normal follicle-stimulating hormone level or testicular volume. Patients with early maturation arrest have a greater incidence of genetic anomalies and are more likely to have worse reproductive outcomes than are patients with late maturation arrest.

Hand Assisted Retroperitoneoscopic Nephroureterectomy With the Patient Spread-Eagled: An Approach Through a Completely Supine Position

PURPOSEnWe evaluated the feasibility of hand assisted retroperitoneoscopic nephroureterectomy for transitional cell carcinoma of the upper urinary tract with the patient completely supine (spread-eagled).nnnMATERIALS AND METHODSnFrom October 2006 to January 2008 hand assisted retroperitoneoscopic nephroureterectomy with open bladder cuff excision was performed in 32 patients with upper tract transitional cell carcinoma. The patient was placed supine with the legs extended and abducted at 45 to 60 degrees, and the arms stretched out to the sides in the spread-eagle position. The patient was secured to the operation table with 3-inch tapes to permit lateral table tilt. The operation was completed via a 7 or 8 cm Gibson incision plus 2 laparoscopic ports.nnnRESULTSnAll procedures were successful. The mean time needed for hand assisted retroperitoneoscopic nephroureterectomy and bladder cuff resection was 137.6 minutes. Mean estimated blood loss was 200 ml. Simultaneous transurethral endoscopic procedures were performed in 8 patients. Time to oral intake was 2.1 days and time to ambulation was 2.0 days. No specific complication was related to the position. All patients recovered to normal daily activity uneventfully.nnnCONCLUSIONSnHand assisted retroperitoneoscopic nephroureterectomy with the patient completely supine is feasible and safe. The completely supine position has several advantages, including ease of patient positioning and the ability to perform simultaneous endoscopic procedures. It not only decreases the time and cost of changing position, but also avoids potential risks associated with the lateral decubitus position. Bowel interference with the visual field and mechanical bowel injury are not a concern using this approach.