Duck Ki Yoon

Renal cell carcinoma does not express argininosuccinate synthetase and is highly sensitive to arginine deprivation via arginine deiminase.

Recently, pegylated arginine deiminase (ADI; EC 3.5.3.6) has been used to treat the patients with hepatocellular carcinoma or melanoma, in which the level of argininosuccinate synthetase (ASS) activity is low or undetectable. The efficacy of its antitumor activity largely depends on the level of intracellular ASS, which enables tumor cells to recycle citrulline to arginine. Thus, we examined the expression levels of ASS in various cancer cells and found that it is low in renal cell carcinoma (RCC) cells, rendering the cells highly sensitive to arginine deprivation by ADI treatment. Immunohistochemical analysis revealed that in biopsy specimens from RCC patients (n = 98), the expression of ASS is highly demonstrated in the epithelium of normal proximal tubule but not seen in tumor cells. Furthermore, RCC cells treated with ADI showed remarkable growth retardation in a dose dependent manner. ADI also exerted in vivo antiproliferative effect on the allografted renal cell carcinoma (RENCA) tumor cells and prolonged the survival of tumor‐bearing mice. Histological examination of the tumors revealed that tumor angiogenesis and vascular endothelial growth factor (VEGF) expression were significantly diminished by ADI administration. Therefore, these findings suggest that arginine deprivation by ADI could provide a beneficial strategy for the treatment of RCC in ways of inhibitions of arginine availability and neovascularization.

Chewing gum has a stimulatory effect on bowel motility in patients after open or robotic radical cystectomy for bladder cancer: a prospective randomized comparative study.

OBJECTIVES To determine whether chewing gum during the postoperative period facilitates the recovery of bowel function and has different efficacy according to operative method used in patients with radical cystectomy. METHODS From July 2007 to September 2009, we randomized open radical cystectomy (ORC) patients into Group AI (ORC without gum chewing) and Group AII (ORC with gum chewing). Robot-assisted radical cystectomy (RARC) patients were randomized into Group BI (RARC without gum chewing) and Group BII (RARC with gum chewing). RESULTS A total of 32 ORC (17 Group AI and 15 Group AII) and 28 RARC (13 Group BI and 15 Group BII) patients were completed. The patients perioperative data between the control (AI + BI) and chewing gum (AII + BII) group showed no differences. The median time to flatus and to bowel movement were significantly reduced in chewing gum group compared with the control patients: 57.1 vs. 69.5 hours 76.7 vs. 93.3 hours. In the ORC patients, decrease in time to flatus and bowel movement were observed in gum chewing (AII) group than control (AI) group: 64.3 vs. 80.3 hours 83.8 vs. 104.2 hours. In RARC patients, decrease in time to flatus and bowel movement were found in gum chewing (BII) group than control (BI) group: 48.8 vs. 60.3 hours 69.1 vs. 84.6 hours. No adverse effects were observed with chewing gum. CONCLUSIONS Chewing gum had stimulatory effects on bowel motility after cystectomy and urinary diversion. Chewing gum was safe and could be used for postoperative ileus regardless of the operative method (ORC or RARC).

Can the prostate risk calculator based on western population be applied to asian population

We developed a Korean Prostate Cancer Risk Calculator (KPCRC) for predicting the probability of a positive initial prostate biopsy using clinical and laboratory data from a Korean male population (http://pcrc.korea.ac.kr). We compared its performance to prostate‐specific antigen (PSA) testing and the Prostate Risk Calculator 3 (PRC 3) based on data from the Dutch part of European Randomized Study of Screening for Prostate Cancer (ERSPC), which predicts biopsy results for previously unscreened men.

The prevalence and risk factors associated with isolated untreated systolic hypertension in Korea: the Korean National Health and Nutrition Survey 2001.

Although isolated systolic hypertension (ISH) increases the risk of coronary heart disease and stroke, more than any other hypertension subtype, the prevalence and risk factors associated with ISH in the Korean population are not known. The 2001 Korean National Health and Nutrition Survey was a cross-sectional and nationally representative survey conducted in 2001. The prevalence of ISH by age and body mass index (BMI) was examined in 6601 Korean adults over 20 years of age. After adjusting for age, 4.32±0.32% of Korean adults had ISH, 5.28±0.37% had isolated diastolic hypertension and 5.82±0.36% had systolic/diastolic hypertension. The overall prevalence of ISH was found to increase directly with advancing age and increasing BMI. Although the ISH was found to be more common in men overall (4.81±0.50% in men, 4.12±0.37% in women), it was more common in women over 70 years of age. Independent variables associated with risk for ISH included advanced age, BMI, triglyceride (TG) levels, monthly income and alcohol intake. However, gender, fasting blood glucose, total cholesterol and high-density lipoprotein cholesterol levels, residential area, education level and smoking were found not to be significantly associated with ISH risk. The findings of the present study demonstrate that the prevalence of untreated ISH in Korea was lower than in Western countries. Age, BMI, TG levels, monthly income and alcohol intake were associated with ISH.

Differences in Tumor Characteristics and Prognosis in Newly Diagnosed Ta, T1 Urothelial Carcinoma of Bladder According to Patient Age

OBJECTIVES To evaluate the differences in tumor characteristics and prognosis according to age at presentation in patients with newly diagnosed Stage Ta, T1 urothelial carcinoma of the bladder. METHODS From 1998 to 2002, 1587 patients with newly diagnosed nonmuscle-invasive bladder cancer treated with transurethral resection were enrolled in this study. The median age was 63 years (range 21-98), and the median follow-up duration was 44 months (range 12-97). The study cohort was subdivided into 3 age groups: age < 60 years (group 1, n = 614), age > or = 60 but < 70 years (group 2, n = 566), and age > or = 70 years (group 3, n = 398). RESULTS Comparing the clinical and pathologic characteristics, the tumor size (chi(2)(trend) = 4.01, P = .045), multiplicity (chi(2)(trend) = 14.50, P < .001), T category (chi(2)(trend) = 17.11, P < .001), and tumor grade (chi(2)(trend) = 31.36, P < .001) tended to increase in the older age groups. The presence of carcinoma in situ and squamous differentiation, however, did not differ among the age groups (P > .05). The 5-year recurrence-free probability was 63.6%, 52.1%, and 43.9% for groups 1, 2, and 3, respectively (P < .001). The 5-year progression-free probability was 95.7%, 91.1%, and 84.2% for groups 1, 2, and 3, respectively (P < .001). CONCLUSIONS Stage Ta, T1 bladder urothelial carcinoma in the younger patients tended to be smaller, have fewer lesions, be less invasive, and have a more favorable tumor grade at the initial presentation. Furthermore, younger patients appeared to have a more favorable prognosis than older patients.

Prostate-specific antigen adjusted for the transition zone volume as a second screening test: a prospective study of 248 cases.

Aim:  This study was conducted to verify the effectiveness of prostate‐specific antigen adjusted for the transition zone volume (PSATZ), and its availability as a second screening test for prostate cancer detection.

Magnetic Resonance Urethrography to Assess Obliterative Posterior Urethral Stricture: Comparison to Conventional Retrograde Urethrography With Voiding Cystourethrography

PURPOSE We prospectively evaluated magnetic resonance urethrography for depicting obliterative posterior urethral stricture. MATERIALS AND METHODS A total of 25 men with a mean age of 48.7 years (range 21 to 72) with complete posterior urethral stricture were studied preoperatively with axial and sagittal turbo spin-echo T2, sagittal T1 and contrast enhanced sagittal T1-weighted images. Of the 25 patients 22 underwent conventional retrograde urethrography with voiding cystourethrography. For magnetic resonance urethrography aseptic lubricant was infused through the external urethral meatus to dilate the distal urethra up to the stricture. Each imaging result was compared with a surgical specimen or a description of the surgical findings. Measurement errors were analyzed using the Wilcoxon signed rank test. The relationship between true and measured stricture length was evaluated by linear regression analysis. RESULTS Based on magnetic resonance urethrography findings 2 patients with a less than 1 cm stricture were treated with internal urethrotomy, 21 with a more than 1 cm stricture underwent open urethroplasty and 2 with prostatic displacement and a 4 cm stricture needed the combined perineal and transpubic approach. The mean +/- SD measurement error on magnetic resonance urethrography imaging was significantly lower than that on conventional retrograde urethrography combined with voiding cystourethrography (0.4 +/- 0.4 vs 1.4 +/- 1.1 cm, p <0.001). Linear regression analysis showed a stronger linear relationship between magnetic resonance urethrography and surgical measurement (r(2) = 0.62, p <0.01). CONCLUSIONS Magnetic resonance urethrography is more effective for evaluating obliterative posterior urethral stricture than retrograde urethrography combined with voiding cystourethrography.

Initial Biopsy Outcome Prediction in Korean Patients-Comparison of a Noble Web-based Korean Prostate Cancer Risk Calculator versus Prostate-specific Antigen Testing

We developed and validated a novel Korean prostate cancer risk calculator (KPCRC) for predicting the probability of a positive initial prostate biopsy in a Korean population. Data were collected from 602 Koreans who underwent initial prostate biopsies due to an increased level of prostate-specific antigen (PSA), a palpable nodule upon digital rectal examination (DRE), or a hypoechoic lesion upon transrectal ultrasound (TRUS). The clinical and laboratory variables were analyzed by simple and multiple logistic regression analysis. The area under the receiver operating characteristic curve (AUC) was computed to compare its performance to PSA testing alone. Prostate cancer was detected in 172 (28.6%) men. Independent predictors included age, DRE findings, PSA level, and prostate transitional zone volume. We developed the KPCRC using these variables. The AUC for the selected model was 0.91, and that of PSA testing alone was 0.83 (P < 0.001). The AUC for the selected model with an additional dataset was 0.79, and that of PSA testing alone was 0.73 (P = 0.004). The calculator is available on the website: http://pcrc.korea.ac.kr. The KPCRC improved the performance of PSA testing alone in predicting the risk of prostate cancer in a Korean population. This calculator would be a practical tool for physicians and patients.

A Matched-cohort Comparison of Laparoscopic Renal Cryoablation using Ultra-thin Cryoprobes with Open Partial Nephrectomy for the Treatment of Small Renal Cell Carcinoma

PURPOSE To evaluate the feasibility and efficacy of performing laparoscopic renal cryoablation (LRC) for the treatment of RCC, as compared with open partial nephrectomy (OPN), which is the established NSS. MATERIALS AND METHODS From April 2004, among the patients who underwent LRC with a 1.47 mm cryoprobe, we enrolled 20 patients who were pathologically confirmed as having RCC with a tumor size smaller than 4 cm. These patients were matched with a group of 20 patients, who were selected based on the pre-operative characteristics of the tumor and those of the patients, from a pre-existing database of the patients who underwent OPN during the same period. RESULTS The mean age and tumor size were 56.3+/-11.5 years and 2.4+/-1.7 cm in the LRC group, and 57.6+/-10.9 years and 2.2+/-1.1 cm in the OPN group. The two groups were similar for their age, gender, BMI, ASA, the tumor characteristics and the indications for operation. While the pathologic results and the operation time showed similarity, the EBL (98+/-87 ml vs 351+/-147 ml, respectively, p=0.001), the transfusion rate (10% vs 40%, respectively, p=0.03) and the hospital stay (4.2+/-1.5 days vs 8.2+/-2.4 days, respectively, p=0.005) were significantly less in the LRC group. Major complications did not occur in the LRC group, but in the OPN group, one patient experienced urine leakage and one patient had a perirenal hematoma. During the mean follow up of 27.3+/-10.8 months and 28.7+/-14.9 months for each group, respectively, all the patients remained disease-free with no evidence of local recurrence or metastases. CONCLUSIONS LRC using ultra-thin cryoprobes for the treatment of small RCC showed similar effective oncologic results with the merits of minimal invasiveness, as compared with OPN, during the intermediate term follow up.

Acute effects of serotonin on rat bladder contractility

Introduction: The purpose of this study is to investigate in vitro the effects of serotonin on the rat detrusor. In particular, it examines which drugs inhibit the serotonin-induced detrusor contractions. Materials and Methods: Isometric tension changes of isolated rat bladder muscle strips were recorded in an organ bath using a force transducer. Acute effects of serotonin (0.0001–0.01 mM) on resting tension were assessed. Electrical field stimulation (EFS); bethanechol (0.0001–0.01 mM); ATP (1–3 mM)- or KCl (63.5–254 mM)-induced contractions using an application in an organ bath were compared with serotonin-induced contractions. In order to examine the action mechanism of serotonin-induced stimulation, EFS-, bethanechol-, ATP- or KCl-induced contraction on serotonin treatment (0.001 mM) was assessed and serotonin (0.001–0.1 mM) was cumulatively added to the organ bath following preincubation with propranolol, ketanserin, tropisetron, propiverine, sodium nitroprusside or doxazosin. Results: The serotonin-induced response has two phases: an initial transient contraction and a prolonged tonic phase. Serotonin produced a reversible and dose-dependent contraction of the detrusor strips. Responses to bethanechol significantly increased with a concentration of 0.001 mM serotonin (p < 0.05). There was no effect on the responses to ATP, KCl, or EFS on 0.001 mM serotonin. The 5-HT2 receptor is mainly responsible for serotonin-induced contractions of the detrusor (p < 0.05), while the 5-HT1 receptor is partially responsible. Doxazosin and propiverine each significantly suppressed the response to serotonin, while sodium nitroprusside and tropisetron each had no effect (p < 0.05). Conclusions: Because the 5-HT2 antagonist blocked the effect of serotonin-induced bladder contractions and the stimulation of the adrenoreceptors, the 5-HT2 antagonist seems to improve lower urinary tract symptoms.