Dong Sup Lee

BIOCOMPATIBILITY OF A PDMS-COATED MICRO-DEVICE： BLADDER VOLUME MONITORING SENSOR

We evaluated the biocompatibility of a dimethylpolysiloxane-coated micro-device which had been designed for monitoring real-time bladder volume in previous studies. The extract assay with dimethylpolysiloxane which had been used for coating the micro-device to measure the bladder volume was performed as an in vitro cytotoxicity test. For in vivo biocompatibility testing, the inflammatory responses around the implantation site of the micro-device in subcutaneous tissue of rat were assessed by light microscope with H&E stain and fluorescence microscope with ED1 stain and von Willebrand factor stain. The averages of cell viability in dimethylpolysiloxane group were 84.6% and 82.3% at 24 h and 72 h incubation, respectively. The qualitative evaluations with light and fluorescence microscope revealed that the inflammatory changes peaked during 2 weeks but almost disappeared at 4 weeks after implantation of devices. The quantitative evaluations for granulation layer formation and neovascularization showed that the thickness of the layer in dimethylpolysiloxane group peaked during 2 weeks but it came to be stabilized at 4 weeks as thin as at 2 weeks in control group, and the frequency of neovascularization was higher in dimethylpolysiloxane group than in control group but it was not increased with time. The dimethylpolysiloxane-coated micro-device is thought be a reliable bio-medical device.

Real-time bladder volume monitoring by the application of a new implantable bladder volume sensor for a small animal model

Although real‐time monitoring of bladder volume together with intravesical pressure can provide more information for understanding the functional changes of the urinary bladder, it still entails difficulties in the accurate prediction of real‐time bladder volume in urodynamic studies with small animal models. We studied a new implantable bladder volume monitoring device with eight rats. During cystometry, microelectrodes prepared by the microelectromechanical systems process were placed symmetrically on both lateral walls of the bladder, and the expanded bladder volume was calculated. Immunohistological study was done after 1 week and after 4 weeks to evaluate the biocompatibility of the microelectrode. From the point that infused saline volume into the bladder was higher than 0.6 mL, estimated bladder volume was statistically correlated with the volume of saline injected (p < 0.01). Additionally, the microelectromechanical system microelectrodes used in this study showed reliable biocompatibility. Therefore, the device can be used to evaluate changes in bladder volume in studies with small animals, and it may help to provide more information about functional changes in the bladder in laboratory studies. Furthermore, owing to its biocompatibility, the device could be chronically implanted in conscious ambulating animals, thus allowing a novel longitudinal study to be performed for a specific purpose.

Comparison of in vivo biocompatibilities between parylene-C and polydimethylsiloxane for implantable microelectronic devices

Implantable devices are often composed of or coated with different biologically compatible materials based on their requirements. Selecting a surface material for an implantable device is not an easy task, and it is necessary to compare the biocompatibilities of the available surface materials. In this study, we perform a comparison of the in vivo biocompatibilities of polydimethylsiloxane (PDMS) and para-xylyene polymer (parylene-C) as they are considered to be candidates for a coating material for implantable microelectronic devices. For in vivo biocompatibility testing, fifty four male Sprague-Dawley rats were used for testing, and they were divided into three groups (PDMS, parylene-C and a positive control). At one, four and twelve weeks after implantation of the test object, the density of inflammatory cells and the granulation layer thickness were recorded for each group and compared with other groups using visible light and fluorescence microscopy. The thickness of the granulation layer tended to decrease over time for all of the experimental groups, whereas the granulation layer thickness remained constant in the positive control group. The thinnest capsular layer was observed for the parylene-C group and fewest inflammatory cells were observed in this group during the entire experimental period. Macrophage infiltration was minimal, even at one week, and was not observed thereafter. The parylene-C group showed better biocompatibility than the PDMS groups, both for acute and chronic implantation. Thus, parylene-C is the best candidate of the tested materials for applications involving permanent implantable micro-devices.

Extending the indication for robot-assisted retroperitoneal partial nephrectomy to antero-lateral renal tumors.

Robot‐assisted retroperitoneal partial nephrectomy (RARPN) is typically employed for posterior renal tumors. This work aimed to extend the indication of RARPN to patients with selected antero‐lateral renal tumor.

Role of age and sex in determining antibiotic resistance in febrile urinary tract infections

OBJECTIVES To identify the age- and sex-specific antimicrobial susceptibility patterns of Gram-negative bacteria (GNB) in outpatient febrile urinary tract infections (UTIs) in Korea. METHODS A total 2262 consecutive samples collected from patients aged 1-101 years with febrile UTIs, during the period January 2012 to December 2014, were analyzed in this multicentre, retrospective cohort study. RESULTS The sensitivities to cefotaxime and cefoxitin were over 85% for females but under 75% for males. Sex played an important role in the susceptibility of GNB to cefotaxime (p<0.001) and cefoxitin (p<0.001). The sensitivity to ciprofloxacin (age >20 years) was under 75% in both sexes, and was not influenced by sex (p=0.204). Age distributions of the incidences of resistance to cefotaxime, cefoxitin, and ciprofloxacin (age >20 years) were similar to the age distribution of the incidence of GNB, which indicates that the resistance patterns to these drugs were not affected by age (Kolmogorov-Smirnov test, female/male: p=0.927/p=0.509, p=0.193/p=0.911, and p=0.077/p=0.999, respectively). CONCLUSIONS Age is not a considerable factor in determining the antibiotic resistance in febrile UTIs. Ciprofloxacin should be withheld from both sexes until culture results indicate its use. Second- or third-generation cephalosporins such as cefoxitin and cefotaxime can be used empirically only in females.

Functional and Molecular Changes of the Bladder in Rats with Crushing Injury of Nerve Bundles from Major Pelvic Ganglion to the Bladder: Role of RhoA/Rho Kinase Pathway

Voiding dysfunction is a common complication after radical pelvic surgery. To reduce this complication, nerve-sparing radical pelvic surgery was introduced. However, several patients experienced voiding difficulty despite nerve-sparing radical pelvic surgery. Thus, we investigated the functional and molecular changes of the bladder in rats, which demonstrated voiding dysfunction induced by nerve damage during nerve-sparing radical pelvic surgery. Male rats were used and assigned to normal, sham-operated, and bilateral crushing nerve bundles from major pelvic ganglion (MPG) to bladder group. After one, two, and four-week crushing injury, significantly decreased contractile response and increased connective tissue of the detrusor were observed and these results were reliable findings with voiding difficulty following nerve-sparing radical pelvic surgery. After crushing injury, significantly increased M2 muscarinic receptor expression was observed and this might be regarded as the compensatory response. However, M3 muscarinic receptor expression was not significantly changed. The expression of RhoA, ROCK-α, and ROCK-β was significantly increased after one, two, and four-week crushing injury. From these results, the down-regulation of RhoA/Rho kinase pathway might lead to the decreased bladder contractility after crushing injury of nerve bundles from MPG to the bladder despite of the compensated up-regulation of M2 muscarinic receptor.

Impact of the change in urinary and sexual function on health-related quality of life after once daily low-dose mirodenafil treatment in patients with organic erectile dysfunction.

Objective: We aimed to evaluate whether changes in urinary and sexual function can influence health-related quality of life. Patients and Methods: Out of 54 recruited patients, 36 were enrolled, and data for 30 participants with erectile dysfunction were available. At baseline and after 1 and 2 months, each participant completed the International Index of Erectile Function (IIEF-15), the International Prostate Symptom Score (IPSS) and the Medical Outcomes Study Short-Form 36-Item Health Survey (SF-36). Uroflowmetry, post-voiding residual volume and the nocturnal penile tumescence (NPT) test were performed at baseline and at the studys conclusion. Results: Compared with baseline, the IPSS, IIEF-15, peak urinary flow rate, NPT parameters and mental component of the SF-36 exhibited significant improvement at the studys conclusion. Among the symptomatic parameters, the changes in the storage and erectile function parameters contributed significantly to the change in the mental component score on the SF-36 (p = 0.007, R2 = 0.502). Conclusions: The daily administration of low-dose mirodenafil (50 mg) produced improvements in urinary and erectile function with or without sexual stimulation. Furthermore, this therapy enhanced the mental component of health-related quality of life by improving storage and erectile symptoms.

Changes in Urinary and Sexual Function 6 Months after Cystocele Repair with a Polypropylene Mesh

Introduction: We used quantitative parameters obtained during the voiding phase, urinary symptoms and sexual functioning to investigate the symptomatic and functional changes after cystocele repair with a polypropylene mesh. Patients and Methods: The maximum urinary flow rate (Qmax), residual urine (RU) volume and two symptom questionnaires, the Urinary Distress Inventory (UDI-6) and the Female Sexual Function Index (FSFI), were used to retrospectively evaluate 39 consecutive cystocele patients before and 6 months after surgery. Results: Qmax, RU and FSFI were not significantly different (p = 0.366, 0.286 and 0.100, respectively) pre- and postoperatively, but the UDI-6 score had significantly improved (p < 0.001) 6 months after the cystocele repair. A concomitant sling procedure was significantly correlated with changes in the UDI-6 score (p < 0.001); the patients without stress urinary incontinence (SUI) who underwent cystocele repair only showed no symptomatic improvements in the UDI-6 score (p = 0.560). Conclusions: Correction of SUI resulted in urinary symptom improvement in cystocele patients. Cystocele repair with or without sling placement did not change Qmax, RU or sexual functioning at the 6-month follow-up.

Prevalence and Antimicrobial Susceptibility of Ureaplasma spp. and Mycoplasma hominis in Asymptomatic Individuals in Korea

This study investigated the prevalence and antibiotic resistance of Ureaplasma spp. and Mycoplasma hominis isolated from asymptomatic individuals in Korea. Endocervical swabs from women and urine from men, from a total of 5,781 asymptomatic individuals, were analyzed using a Mycoplasma IST2 Kit. Of the 4,825 specimens tested from females, 486 (10.1%) were positive culture. In these positive specimens, 437 (9.1%) were positive only for Ureaplasma spp., 17 (0.4%) were positive only for M. hominis, and 32 (0.7%) were positive for both Ureaplasma spp. and M. hominis. In males, of the 956 tested specimens, only 4 (0.42%) were positive for Ureaplasma spp. and no M. hominis colonization was identified. In antimicrobial susceptibility tests, more than 93.2% of both M. hominis and Ureaplasma spp. was susceptible to tetracycline, doxycycline, josamycin, and pristinamycin. However, M. hominis isolates were found to be highly resistant to erythromycin, azithromycin, and clarithromycin (82.4%, 70.6%, and 76.5%, respectively). Ofloxacin and ciprofloxacin, which have recently exhibited increasing resistance rates, showed rates of 17.7% and 35.3%, respectively, in M. hominis, and 50.6% and 27.4%, respectively, in Ureaplasma spp. In conclusion, accurate antimicrobial susceptibility tests of the genital mycoplasmas should be conducted for each case to select the appropriate antibiotics. Fluoroquinolone-based drugs should be avoided in the initial treatment of urogenital mycoplasmas because of the increasing rate of resistance to quinolones, although the susceptibility to tetracycline remains high in Korea.

Co-infection Of Ureaplasma urealyticum And Human Papilloma Virus In Asymptomatic Sexually Active Individuals

This study aimed to determine the role of asymptomatic bacterial sexually transmitted infections (STIs), such as Chlamydia trachomatis (Ct), Mycoplasma genitalium (Mg), Mycoplasma hominis (Mh), and Ureaplasma urealyticum (Uu) in human papillomavirus (HPV) infection. In total, 264 asymptomatic outpatients aged between 21 and 80 years were prospectively enrolled in this study during routine gynecological screening tests. Specimens collected with a Cervex Brush were routinely analyzed with the Hybrid Capture 2 assay for HPV. Simultaneously, a specimen obtained with an endocervical swab was used to detect Ct and Mg with a monoplex real-time polymerase chain reaction (PCR) and to confirm Mh and Uu with a Mycoplasma IST 2 kit. The detection rates (%) of HPV, Ct, Mg, Mh, and Uu were 82/264 (31.1), 6/264 (2.3), 5/264 (1.9), 16/264 (6.1), and 95/264 (36.0), respectively. Of 95 Uu, 32 (33.7%) showed high density colonization (HDC, ≥104 color-changing units/mL). HDC-Uu was significantly associated with HPV infection (p=0.014, chi-square test). Mg infection and Mh infection were not associated with HPV infection (p=0.981 and p=0.931, chi-square test). Age was not associated with HPV infection or bacterial infection. Our data suggested that asymptomatic HDC-Uu was closely associated with HPV infection. Therefore, simultaneous evaluation for Uu and HPV should be performed during gynecological screening, even in asymptomatic individuals.