A predictive model towards understanding the effect of reinforcement agglomeration on the stiffness of nanocomposites.

Nanocomposite technologies can be significantly enhanced through a careful exploration of the effects of agglomerates on mechanical properties. Existing models are either overly simplified (e.g., neglect agglomeration effects) or often require a significant amount of computational resources. In this study, a novel continuum-based model with a statistical approach was developed. The model is based on a modified three-phase Mori-Tanaka model, which accounts for the filler, agglomerate, and matrix regions. Fillers are randomly dispersed in a defined space to predict agglomeration tendency. The proposed model demonstrates good agreement with the experimentally measured elastic moduli of spin-coated cellulose nanocrystal reinforced polyamide-6 films. The techniques and methodologies presented in the study are sufficiently general in that they can be extended to the analyses of various types of polymeric nanocomposite systems.

The role of interface on the toughening and failure mechanisms of thermoplastic nanocomposites reinforced with nanofibrillated rubber.

The interface plays a crucial role in the physical and functional properties of polymer nanocomposites, yet its effects have not been fully recognized in the setting of classical continuum-based modeling. In the present study, we investigate the roles of interface and interfiber interactions on the toughening effects of rubber nanofibers embodied in thermoplastic-based materials. Emphasis is placed on establishing comprehensive theoretical and atomistic descriptions of the nanocomposite systems subjected to pull-out and uniaxial extension in the longitudinal and transverse directions. Using the framework of molecular dynamics, the annealed melt-drawn nanofibers were spontaneously formed via the proposed four-step methodology. The generated nanofibers were then crosslinked using the proposed robust topology-matching algorithm, through which the chemical reactions arising in the crosslinking were closely assimilated. The interfiber interactions were also examined with respect to separation distances and nanofiber radius via a nanofiber-pair atomistic scheme, and the obtained results were subsequently incorporated into the pull-out and uniaxial test simulations. The results indicate that the compatibilizer grafting results in enhanced interfacial shear strength by introducing extra chemical interactions at the interface. In particular, it was found that the compatibilizer restricts the formation and coalescence of nanovoids, resulting in enhanced toughening effects. Together, we have shown that the presence of a small amount of well-dispersed rubber nanofibrillar network whose surfaces are grafted with maleic anhydride compatibilizer can dramatically increase the toughness and alter the failure mechanisms of the nanocomposites without any deterioration in the stiffness, which is also consistent with the recent experimental observations in our lab. The interfacial failure mechanism was also investigated by monitoring the changes in the atomic concentration profiles, mean square displacement and fractional free volume. The results obtained may serve as a promising alternative for the continuum-based modeling and analysis of interfaces.

Effect of Surface and Interfacial Tension on the Resonance Frequency of Microfluidic Channel Cantilever.

The bending resonance of micro-sized resonators has been utilized to study adsorption of analyte molecules in complex fluids of picogram quantity. Traditionally, the analysis to characterize the resonance frequency has focused solely on the mass change, whereas the effect of interfacial tension of the fluid has been largely neglected. By observing forced vibrations of a microfluidic cantilever filled with a series of alkanes using a laser Doppler vibrometer (LDV), we studied the effect of surface and interfacial tension on the resonance frequency. Here, we incorporated the Young-Laplace equation into the Euler-Bernoulli beam theory to consider extra stress that surface and interface tension exerts on the vibration of the cantilever. Based on the hypothesis that the near-surface region of a continuum is subject to the extra stress, thin surface and interface layers are introduced to our model. The thin layer is subject to an axial force exerted by the extra stress, which in turn affects the transverse vibration of the cantilever. We tested the analytical model by varying the interfacial tension between the silicon nitride microchannel cantilever and the filled alkanes, whose interfacial tension varies with chain length. Compared with the conventional Euler-Bernoulli model, our enhanced model provides a better agreement to the experimental results, shedding light on precision measurements using micro-sized cantilever resonators.

Salt coatings functionalize inert membranes into high-performing filters against infectious respiratory diseases.

Respiratory protection is key in infection prevention of airborne diseases, as highlighted by the COVID-19 pandemic for instance. Conventional technologies have several drawbacks (i.e., cross-infection risk, filtration efficiency improvements limited by difficulty in breathing, and no safe reusability), which have yet to be addressed in a single device. Here, we report the development of a filter overcoming the major technical challenges of respiratory protective devices. Large-pore membranes, offering high breathability but low bacteria capture, were functionalized to have a uniform salt layer on the fibers. The salt-functionalized membranes achieved high filtration efficiency as opposed to the bare membrane, with differences of up to 48%, while maintaining high breathability (> 60% increase compared to commercial surgical masks even for the thickest salt filters tested). The salt-functionalized filters quickly killed Gram-positive and Gram-negative bacteria aerosols in vitro, with CFU reductions observed as early as within 5 min, and in vivo by causing structural damage due to salt recrystallization. The salt coatings retained the pathogen inactivation capability at harsh environmental conditions (37 °C and a relative humidity of 70%, 80% and 90%). Combination of these properties in one filter will lead to the production of an effective device, comprehensibly mitigating infection transmission globally.

Deformation analysis of lipid membranes subjected to general forms of intra-membrane viscous flow and interactions with an elliptical-cross-section substrate.

We study the morphology of lipid membranes subjected to intra-membrane viscous flows and interactions with elliptical cylinder substrates. From the non-linear theory of elastic surfaces, a linearized shape equation and admissible boundary conditions are formulated in elliptical coordinates via the Monge representation of a surface. In particular, the intra-membrane viscosity terms are linearized and mapped into elliptic coordinates in order to accommodate more general forms of viscous flow. The assimilated viscous flow is characterized by potential functions which satisfies the continuity condition. A complete solution in terms of Mathieu function is then obtained within the prescription of incremental deformations superposed on large. The results describe smooth morphological transitions over the domain of interest and, more importantly, predicts wrinkle formations in the presence of intra-membrane viscous flow in the surface. Lastly, the obtained solution accommodates the results from the circular cases in the limit of vanishing eccentricity and intra-membrane viscous flow.

Mimicking "J-Shaped" and Anisotropic Stress-Strain Behavior of Human and Porcine Aorta by Fabric-Reinforced Elastomer Composites.

An ex vivo heart perfusion device preserves the donor heart in a warm beating state during transfer between extraction and implantation surgeries. One of the current challenges includes the use of rigid and noncompliant plastic tubes, which causes injuries to the heart at the junction between the tissue and the tube. The compliant and rapidly strain-stiffening mechanical property that generates a "J-shaped" stress-strain behavior is necessary for producing the Windkessel effect, which ensures continuous flow of blood through the aorta. In this study, we mimic the J-shaped and anisotropic stress-strain behavior of human aorta in synthetic elastomers to replace the problematic noncompliant plastic tube. First, we assess the mechanical properties of human (n = 1) and porcine aorta (n = 14) to quantify the nonlinear and anisotropic behavior under uniaxial tensile stress from five different regions of the aorta. Second, fabric-reinforced elastomer composites were prepared by reinforcing silicone elastomers with embedded fabrics in a trilayer geometry. The knitted structures of the fabric provide strain-stiffening as well as anisotropic mechanical properties of the resulting composite in a deterministic manner. By optimizing the combination between different elastomers and fabrics, the resulting composites matched the J-shaped and anisotropic stress-strain behavior of natural human and porcine aorta. Finally, improved analytical constitutive models based on Gent's and Mooney-Rivlin's constitutive model (to describe the elastomer matrix) combined with Holzapfel-Gasser-Ogden's model (to represent the stiffer fabrics) were developed to describe the J-shaped behavior of the natural aortas and the fabric-reinforced composites. We anticipate that the suggested fabric-reinforced silicone elastomer composite design concept can be used to develop complex soft biomaterials, as well as in emerging engineering fields such as soft robotics and microfluidics, where the Windkessel effect can be useful in regulating the flow of fluids.

The Effects of Intra-membrane Viscosity on Lipid Membrane Morphology: Complete Analytical Solution.

We present a linear theory of lipid membranes which accommodates the effects of intra-membrane viscosity into the model of deformations. Within the Monge parameterization, a linearized version of the shape equation describing membrane morphology is derived. Admissible boundary conditions are taken from the existing non-linear model but reformulated and adopted to the present framework. We obtain a complete analytical expression illustrating the deformations of lipid membrane subjected to the influences of intra-membrane viscosity. The result predicts wrinkle phenomena in the event of membrane-substrate interactions. Finally, we mention that the obtained solutions reduce to those from the classical shape equation when the viscosity effects are removed.

Updated clinical results of active surveillance of very-low-risk prostate cancer in Korean men: 8 years of follow-up.

PURPOSE: Update and reanalysis of our experience of active surveillance (AS) for prostate cancer (PCa) in Korea. MATERIALS AND METHODS: A prospective, single-arm, cohort study was initiated in January 2008. Patients were selected according to the following criteria: Gleason sum ≤6 with single positive core with ≤30% core involvement, clinical stage≤T1c, prostate-specific antigen (PSA)≤10 ng/mL, and negative magnetic resonance imaging (MRI) results. Follow-up was by PSA measurement every 6 months, prostate biopsies at 1 year and then every 2-3 years, and MRI every year. RESULTS: A total of 80 patients were treated with AS. Median follow-up was 52 months (range, 6-96 months). Of them, 39 patients (48.8%) discontinued AS for various reasons (17, disease progression; 9, patient preference; 10, watchful waiting due to old age; 3, follow-up loss; 2, death). The probability of progression was 14.0% and 42.9% at 1 and 3 years, respectively. Overall survival was 97.5%. PCa-specific survival was 100%. Progression occurred in 5 of 7 patients (71.4%) with a prostate volume less than 30 mL, 7 of 40 patients (17.5%) with a prostate volume of 30 to 50 mL, and 5 of 33 patients (15.2%) with a prostate volume of 50 mL or larger. There were 8 detectable positive lesions on follow-up MRI. Of them, 6 patients (75%) had actual progressed disease. CONCLUSIONS: Small prostate volume was associated with a tendency for cancer progression. MRI was helpful and promising for managing AS. Nevertheless, regular biopsies should be performed. AS is a safe and feasible treatment option for very-low-risk PCa in Korea. However, AS should continue to be used in carefully selected patients.

Pathological upgrading in prostate cancer patients eligible for active surveillance: Does prostate-specific antigen density matter?

PURPOSE: To evaluate prospectively the role of prostate-specific antigen (PSA) density in predicting Gleason score upgrading in prostate cancer patients eligible for active surveillance (T1/T2, biopsy Gleason score≤6, PSA≤10 ng/mL, and ≤2 positive biopsy cores). MATERIALS AND METHODS: Between January 2010 and November 2013, among patients who underwent greater than 10-core transrectal ultrasound-guided biopsy, 60 patients eligible for active surveillance underwent radical prostatectomy. By use of the modified Gleason criteria, the tumor grade of the surgical specimens was examined and compared with the biopsy results. RESULTS: Tumor upgrading occurred in 24 patients (40.0%). Extracapsular disease and positive surgical margins were found in 6 patients (10.0%) and 8 patients (17.30%), respectively. A statistically significant correlation between PSA density and postoperative upgrading was found (p=0.030); this was in contrast with the other studied parameters, which failed to reach significance, including PSA, prostate volume, number of biopsy cores, and number of positive cores. Tumor upgrading was also highly associated with extracapsular cancer extension (p=0.000). The estimated optimal cutoff value of PSA density was 0.13 ng/mL(2), obtained by receiver operating characteristic analysis (area under the curve=0.66; p=0.020; 95% confidence interval, 0.53-0.78). CONCLUSIONS: PSA density is a strong predictor of Gleason score upgrading after radical prostatectomy in patients eligible for active surveillance. Because tumor upgrading increases the potential for postoperative pathological adverse findings and prognosis, PSA density should be considered when treating and consulting patients eligible for active surveillance.

Relationships between the effect of sunitinib and immature blood vessels in metastatic renal cell cancer.

INTRODUCTION: This study was conducted to investigate the relationships between the effect of sunitinib and immature microvessels which are not covered by pericytes. MATERIALS AND METHODS: This study involved 29 patients with clear-cell renal cell carcinoma (RCC) who took sunitinib after radical nephrectomy or biopsy due to metastatic RCC. Associations among clinicopathological factors, responses to sunitinib, and patient survival were reviewed. CD31 was used to stain endothelial cells, and anti-α-smooth muscle actin was used to stain pericytes. Immature vessels were defined as vessels that were positive only for CD31 staining. A high pericyte coverage was defined as a rate of pericyte coverage above 40%. RESULTS: Partial responses, disease stabilization, and disease progression constituted 51.7, 10.4, and 37.9% of cases, respectively. Nine cases had a low pericyte coverage (31.0%). In the high-pericyte-coverage group, the number of metastatic sites was smaller (p=0.003). The overall response rate to sunitinib was greater in the high-pericyte-coverage group than in the low-pericyte-coverage group (p=0.027). The median overall survival and the median progression-free survival were not significantly different between the high- and low-pericyte-coverage groups. CONCLUSION: In the high-pericyte-coverage group, the overall response rates to sunitinib were higher, and the numbers of metastatic sites were smaller.

Early experience with active surveillance in low-risk prostate cancer treated.

PURPOSE: This study was conducted to describe our early experience with active surveillance (AS). MATERIALS AND METHODS: Between January 2008 and December 2012, 35 patients were treated with AS. Selection criteria included the following: Gleason score ≤6 with single positive core, clinical stage ≤T1c, prostate-specific antigen (PSA) ≤10 ng/mL, and unremarkable imaging results. On patient follow-up, we regularly measured PSA (every 3-6 months) and performed prostate biopsies (after 1 and 3 years). RESULTS: In the first year of follow-up, prostate biopsies were performed in 25 patients (13 patients, negative for cancer; 7 patients, Gleason score of 6 without progression; 5 patients, progression, treated with radical prostatectomy [RP]). In the third year of follow-up, prostate biopsies were performed in five patients (two patients, negative for cancer; one patient, Gleason score of 6 without progression; two patients, progression, treated with RP). Seven patients discontinued AS because of increased anxiety, and three patients were lost to follow-up. Overall, seven patients (28%) who experienced progression had a mean PSA doubling time (DT) of 7.54 years. Six patients had a PSA DT of more than 3 years, whereas one had a PSA DT of less than 3 years. This study was limited by its small sample size and short follow-up period. CONCLUSIONS: PSA kinetics did not correlate with progression, which suggests that regular biopsies should still be performed. AS is an available treatment option for patients with a low risk of prostate cancer but should only be used in carefully selected patients.

Effect of overexpression of glucose-regulated protein 78 and bcl-2 on recurrence and survival in patients with ureter tumors.

PURPOSE: The utility of the expression of glucose-regulated protein 78 (GRP78) in the evaluation of prognosis depends on the type of tumor. Hence, we aimed to examine the impact of expression of GRP78 and Bcl-2, which are used in the existing prognostic evaluation of ureter tumors, in the evaluation of recurrence and survival rates of ureter tumors. MATERIALS AND METHODS: In 53 patients who had undergone radical nephroureterectomy for a ureter tumor from March 2002 to March 2012, age, sex, T stage, nuclear grade, bladder recurrence, and survival rate were analyzed at the time of the patient's surgery depending on the extent of immunohistochemical expression of GRP78 and Bcl-2. RESULTS: GRP78 was overexpressed in 25 patients (47.2%). When GRP78 was overexpressed, there was a high T stage (p=0.001) and nuclear grade (p=0.007) and a lot of bladder recurrence (40.0%, p=0.034). Bcl-2 was overexpressed in 16 patients (30.1%), and there were no significant associations with any risk factors (p>0.05, respectively). In the multivariate analysis regarding bladder recurrence, the recurrence rate was higher with higher pT stage (p=0.048) and when GRP78 (p=0.033) was overexpressed. In the Kaplan-Meier survival analysis, although the survival rate was significantly lower in the group in which GRP78 was overexpressed (p=0.03), there was no correlation between Bcl-2 overexpression and survival rate (p=0.07). CONCLUSIONS: Patients with ureter tumors who had overexpression of GRP78 had a high T stage and nuclear grade, a lot of bladder recurrence, and a low survival rate. Therefore, if GRP78 is overexpressed in ureter tumor patients, active postoperative follow-up should be carried out.

Relationship Between Spontaneous Passage Rates of Ureteral Stones Less Than 8 mm and Serum C-Reactive Protein Levels and Neutrophil Percentages.

PURPOSE: A ureter obstruction caused by a ureteral stone results in inflammatory changes in the proximal submucosal layer and prevents the spontaneous passage of the ureteral stone. Accordingly, we analyzed the relationship between the spontaneous passage rates of ureteral stones less than 8 mm in size and serum C-reactive protein (CRP) levels and neutrophil percentages. MATERIALS AND METHODS: A total of 187 patients who were diagnosed with ureteral stones less than 8 mm in size and were managed consecutively at Keimyung University Dongsan Medical Center from January 2001 to January 2011 were retrospectively analyzed. Ureteral stone removal was defined as no ureteral stone shown in an imaging test without any treatment for 8 weeks after diagnosis. The patients were divided into three groups according to the levels of serum CRP and into two groups according to neutrophil percentage. The associations between these factors and ureteral stone passage rates were then examined. RESULTS: The ureteral stone passage rates of the low serum CRP level group, the medium serum CRP level group, and the high serum CRP level group were 94.1% (159/169), 70% (7/10), and 50.0% (4/8), respectively. The passage rates of ureteral stones in the group with a normal neutrophil percentage and in the group with a higher neutrophil percentage were 94.5% (121/128) and 83.1% (49/59), respectively (p=0.011). CONCLUSIONS: Measuring serum CRP levels and neutrophil percentages in patients with small ureteral stones of less than 8 mm is useful in predicting whether the stone will be spontaneously passed. When the serum CRP level and neutrophil percentage of a patient are high, aggressive treatment such as extracorporeal shock wave lithotripsy should be considered.

Survey on benign prostatic hyperplasia distribution and treatment patterns for men with lower urinary tract symptoms visiting urologists at general hospitals in Korea: a prospective, noncontrolled, observational cohort study.

OBJECTIVE: To survey cases of benign prostatic hyperplasia (BPH) among patients visiting urologists with lower urinary tract symptoms (LUTS) at general hospitals in Korea and to investigate treatment outcomes in current clinical practice. METHODS: This was a multicenter, prospective study conducted in 18 urology centers in Korea. The symptoms of BPH were observed via the International Prostate Symptoms Score (IPSS), transrectal ultrasonography, uroflometry, prostate, specific, antigen, PSA) and postvoid residual volume at the baseline, 1 week, 4 weeks, 12 weeks, 24 weeks, and 52 weeks after initial evaluation. The patients were divided into three groups according to age (group I: 50-59; group II: 60-69; group III: 70 years or older). RESULTS: Of the 1054 screened men, 966 were enrolled and 917 were diagnosed with BPH. Total IPSS and storage subscores were significantly higher in group III than in group II or I. By month 12, significant improvements on total IPSS and voiding subscores were demonstrated in group I over groups II and III (P = .02. 03, respectively). The incidence of dual combination therapy was significantly higher in the patients whose prostate volume was ≥30 mL and whose PSA was ≥1.5. CONCLUSION: At the initial visit, patients with LUTS/BPH, especially those who were relatively young, visited urologic centers because of to voiding symptoms rather than storage symptoms. In contrast, elderly men who visited the urologic centers complained not only of voiding symptoms but also storage symptoms. However, at 12 months' follow up, all of the age groups showed improvement in both storage and voiding symptoms.

α-blocker monotherapy and α-blocker plus 5-alpha-reductase inhibitor combination treatment in benign prostatic hyperplasia; 10 years' long-term results.

PURPOSE: We compared the effects of alpha-adrenergic receptor blocker (α-blocker) monotherapy with those of combination therapy with α-blocker and 5-alpha-reductase inhibitor (5-ARI) on benign prostatic hyperplasia (BPH) progression for over 10 years. MATERIALS AND METHODS: A total of 620 patients with BPH who received α-blocker monotherapy (α-blocker group, n=368) or combination therapy (combination group, n=252) as their initial treatment were enrolled from January 1989 to June 2000. The incidences of acute urinary retention (AUR) and BPH-related surgery were compared between the two groups. Incidences stratified by follow-up period, prostate-specific antigen (PSA), and prostate volume (PV) were compared between the two groups. RESULTS: The incidence of AUR was 13.6% (50/368) in the α-blocker group and 2.8% (7/252) in the combination group (p<0.001). A total of 8.4% (31/368) and 3.2% (8/252) of patients underwent BPH-related surgery in the α-blocker and combination groups, respectively (p=0.008). According to the follow-up period, the incidence of AUR was significantly decreased in combination group. However, the incidence of BPH-related surgery was significantly reduced after 7 years of combination therapy. Cutoff levels of PSA and PV for reducing the incidences of AUR and BPH-related surgery were 2.0 ng/ml and 35 g, respectively (p<0.001). CONCLUSIONS: Long-term combination therapy with α-blocker and 5-ARI can suppress the progression of BPH more efficiently than α-blocker monotherapy. For patients with BPH with PSA >2.0 ng/ml or PV >35 ml, combination therapy promises a better effect for reducing the risk of BPH progression.

Usefulness of preoperative serum testosterone as a predictor of extraprostatic extension and biochemical recurrence.

PURPOSE: A great variety of studies on preoperative serum testosterone as a predictor of progression of prostate cancer have been reported recently. The purpose of this study was to investigate the relationship of preoperative serum testosterone levels in patients who underwent radical prostatectomy with prognostic factors. MATERIALS AND METHODS: Clinical data were collected from 60 patients who underwent radical prostatectomy. The 60 cases were divided into 2 groups according to their preoperative serum testosterone levels: group 1 (n=21), <3 ng/ml; group 2 (n=39), ≥3 ng/ml. The groups were compared according to prog-ression factors. Multivariate logistic regression analysis was performed to determine the correlation between biochemical recurrence and each variable. RESULTS: The incidence of extraprostatic invasions was significantly higher in group 1 with 13 cases in group 1 (61.9%) and 11 cases in group 2 (28.2%) (p=0.011). The incidence of biochemical recurrence was also significantly higher in group 1 with 5 cases in group 1 (23.8%) and 2 cases in group 2 (5.1%) (p=0.032). A low serum testosterone level (≤3 ng/ml) was associated with an increased risk of biochemical recurrence (odds ratio [OR], 13.64; 95% confidence interval [CI], 1.66 to 2.43; p=0.015) and an increased risk of extraprostatic invasions (OR, 4.96; 95% CI, 1.41 to 17.38; p=0.012). CONCLUSIONS: The incidence rates of extraprostatic invasions and biochemical recurrence were significantly higher in the group with preoperative average serum testosterone of less than 3 ng/ml. Therefore, these results suggest that preoperative average serum testosterone will be useful in predicting postoperative prostate cancer progression.

Correlation between Chemokine Receptor CXCR4 Expression and Prognostic Factors in Patients with Prostate Cancer.

PURPOSE: We evaluated the correlation between the expression of CXCR4 and prognostic factors in patients with prostate cancer. MATERIALS AND METHODS: A total of 57 patients who had undergone surgery for prostate cancer were enrolled. Specimens were obtained before any treatment and were stained with antihuman CXCR4 antibody. The intensity of staining was graded as low or high. The age, pretreatment prostate-specific antigen (PSA) level, Gleason score, T stage, biochemical recurrence, local recurrence, and distant metastasis were compared according to the expression of CXCR4 in patients with prostate cancer. RESULTS: Local recurrence was higher in the group with high expression, in 11 of 36 cases (30.6%), than in the group with low expression, in 1 of 21 cases (4.8%), with statistical significance (p=0.040). Distant metastasis was also associated with expression, occurring in 10 of 36 cases (27.8%) in the group with high expression and in 1 of 21 cases (4.8%) in the group with low expression (p=0.041). In the logistic regression test, CXCR4 expression was the only factor in determining local recurrence (p=0.016) and distant metastasis (0.022). Furthermore, the group with high CXCR4 expression showed significantly longer cancer-specific survival than did the low expression group (p=0.041). CXCR4 showed no association with age (p=0.881), pretreatment PSA level (p=0.584), Gleason score (p=0.640), T stage (p=0.967), or biochemical recurrence (p=0.081). CONCLUSIONS: The high expression of CXCR4 was associated with local recurrence and distant metastasis. CXCR4 expression was shown to be a useful prognostic factor for patients with prostate cancer.

Efficacy and Tolerability of Tamsulosin 0.4 mg in Patients with Symptomatic Benign Prostatic Hyperplasia.

PURPOSE: To evaluate the efficacy and tolerability of tamsulosin 0.4 mg once daily in Korean patients with symptomatic benign prostatic hyperplasia (BPH) and investigate whether tamsulosin 0.4 mg can improve symptoms in patients with refractory lower urinary tract symptoms (LUTS) who were previously receiving tamsulosin 0.2 mg once daily. MATERIALS AND METHODS: A total of 116 patients from 3 urology centers participated. All study subjects entered a nonblind phase consisting of 8 weeks of tamsulosin 0.2 mg monotherapy followed by an additional 8 weeks of tamsulosin 0.2 mg (0.2 mg group) or 8 weeks of tamsulosin 0.4 mg (0.4 mg group). At week 8, we chose the 0.4 mg group on the basis of International Prostate Symptom Score (IPSS), quality of life (QoL), maximal urinary flow rate (Qmax), and adverse effects. At week 16, we compared the efficacy and tolerability of tamsulosin between the 0.2 and 0.4 mg groups. RESULTS: A total of 26 patients (22.4%) were escalated to tamsulosin 0.4 mg at week 8. There were significant differences in IPSS, QoL, and Qmax at week 8 in both groups. There were significant differences in improvement in IPSS, QoL, Qmax, and postvoid residual urine volume from baseline to week 16 in both groups. There were no significant differences in efficacy or tolerability between the groups at week 16. CONCLUSIONS: Our trial demonstrated that tamsulosin 0.4 mg has favorable efficacy and tolerability in Korean patients with symptomatic BPH refractory to tamsulosin 0.2 mg. No patients experienced any serious adverse effects when we escalated the dose of tamsulosin to 0.4 mg.

Current status of transurethral prostatectomy: a korean multicenter study.

PURPOSE: We aimed to verify the current status of transurethral resection of the prostate (TURP) in Korea. MATERIALS AND METHODS: The medical records of 1,341 men who underwent TURP in 9 Korean medical centers between 2004 and 2008 were reviewed. The patients were divided into two groups according to time periods: 2004-2005 (group 1) and 2006-2008 (group 2). To verify differences in the two patient groups, age, prostate volume, indications for TURP, preoperative International Prostate Symptom Score (IPSS), and resected tissue weight were evaluated. RESULTS: The mean age of the patients was 71.2 years and the mean IPSS was 22.7. The patients' characteristics were not significantly different between the two groups. The annual cases of TURP increased over the study period. The proportion of lower urinary tract symptoms (LUTS) as an indication for TURP increased up to 58.3% in group 2 compared with 51.6% in group 1 (p=0.019). However, the proportion of patients who presented with acute urinary retention decreased from 35.5% to 30.3% with marginal statistical significance (p=0.051). Other indications such as hematuria, bladder stone, recurrent urinary tract infection, and hydronephrosis were not significantly different between the groups. The mean resected weights of the prostate were similar (17.5 g in group 1 and 18.3 g in group 2, respectively; p>0.05). CONCLUSIONS: TURP has been steadily performed in patients with benign prostatic hyperplasia and it is expected to remain constant. LUTS was the most common indication for TURP in recent years.

Expression of claudin-1 and -7 in clear cell renal cell carcinoma and its clinical significance.

PURPOSE: We investigated the correlations between the expression of claudin-1 and claudin-7 in clear cell renal cell carcinoma (clear cell RCC) and clinical parameters. MATERIALS AND METHODS: The subjects of this study were 119 patients with confirmed clear cell RCC between January 2000 and December 2007. Their RCC tissues were immunohistochemically stained for claudin-1 and claudin-7. The correlations between the expression of claudin and parameters such as sex, age, body mass index (BMI), tumor size, TNM stage, Furhman nuclear grade, postoperative distant metastasis, and cancer-specific survival were analyzed. RESULTS: Among the total 119 subjects, claudin-1 was expressed in 18 (15.1%) and claudin- 7 in 31 (26.1%). Claudin-1 was expressed in patients who were older (p=0.007), who had a greater tumor size (p=0.001), who had a higher pathologic T stage (p=0.009), who had preoperative distant metastasis (p=0.035), and who had a higher Furhman nuclear grade (p=0.004). Claudin-7 was expressed only in patients who had a higher Furhman nuclear grade (p=0.031). The risk of postoperative distant metastasis was associated with the expression of claudin-1 (p<0.001) but not with the expression of claudin-7 (p=0.668). The expression of claudin-1 and -7 was not associated with cancer-specific survival (p>0.05). CONCLUSIONS: In clear cell RCC, claudin-1 was expressed in patients who were older and who had a greater tumor size, who had higher T or M stages, and who had a higher Furhman nuclear grade. The expression of claudin-1 was associated with a higher risk of postoperative distant metastasis.