Hyun Jun Park

Pusan National University, Tsau-liang-hai, Busan, South Korea

Are you Hyun Jun Park?

Claim your profile

Publications (51)59.82 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: To investigate the reasons for prescription change of α1-blockers in patients with lower urinary tract symptoms suggestive of benign prostatic hyperplasia.
    Urology 06/2014; · 2.42 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Phosphodiesterase type 5 (PDE5) inhibitors are the most commonly used treatment for erectile dysfunction (ED). Since the launch of sildenafil, several drugs-including mirodenafil, sildenafil citrate (sildenafil), tadalafil, vardenafil HCL (vardenafil), udenafil, and avanafil-have become available. Mirodenafil is a newly developed pyrrolopyrimidinone compound, which is a potent, reversible, and selective oral PDE5 inhibitor. Mirodenafil was launched in Korea in 2007, and an orally disintegrating film of mirodenafil was developed in 2011 for benefitting patients having difficulty in swallowing tablets. This study aimed to review the pharmacokinetic characteristic profile of mirodenafil and report evidence on its efficacy in the case of ED. In addition, we reviewed randomized controlled studies of mirodenafil's daily administration and efficacy for lower urinary tract symptoms.
    The world journal of men's health. 04/2014; 32(1):18-27.
  • [Show abstract] [Hide abstract]
    ABSTRACT: This post hoc integrated analysis assessed the efficacy and safety of tadalafil 5 mg once daily in a large Korean population with lower urinary tract symptoms suggestive of benign prostatic hyperplasia (BPH-LUTS).
    The world journal of men's health. 04/2014; 32(1):28-35.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Infertile couples interested in nonspouse artificial insemination by donor (AID) not only require a thorough understanding of the medical procedure but also must scrutinize the effects it will have on family relationships, including those on the infant to be born. We conducted a series of surveys in couples with male infertility to collect information necessary for AID counseling. A total of 384 cases with noncurable male infertility were enrolled in this inquiry survey. The questionnaire consisted of 18 items that assessed demographic characteristics, background information concerning the choice to use AID, subjective experiences, long-term effects, and an overall evaluation. A total of 126 surveys were returned (32.8%). AID was first suggested by the husband in about half of the cases. The major reason for considering the procedure was to form a complete family. Two-thirds of the couples were anxious about the procedure, most often about possible congenital or acquired deformities in the infant. After the birth of the child, most couples were positive about their decision to have used AID. About half of the couples felt that the child was their own and expected not to tell the child about AID. Overall, about 50% of the couples were satisfied with the procedure. Those who underwent AID experienced various psychological effects, including anxiety about the child to be born. To overcome these problems, sufficient medical information and consultation about the process of selecting the donor and about AID procedures should be provided before the procedure is used.
    Korean journal of urology 02/2014; 55(2):134-9.
  • Kwang Baek Kim, Hyun Jun Park, Gwang Ha Kim
    [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we propose a new fully computerized image analysis method for measuring the thickness of muscles from ultrasound image obtained by muscle endurance test using morphological information of fascia and thoracic vertebra. Firstly, we divide the image into lumbar region and thoracolumbar region by the difference of density in image for measuring the thickness of muscles. In lumbar region, we notice that the intensity of fascia is relatively higher than other parts. Thus, we measure the thickness of muscles surrounding the fascia area. In the process, we apply median filter to candidate fascia areas for extracting candidate muscle layers between fascias. Then, the thickness of muscles we measure is that of the third layer. In thoracolumbar region, we apply region expansion method for classifying the region into subcutaneous fat part and part including thoracic vertebra. Then, we apply counting method and evolutionary computation search model to find the measuring location that is in between subcutaneous fat area and thoracic vertebra. In experiment, the proposed method is effective in measuring the thickness of muscles and avoids failures of previous studies. The performance of this approach is sufficiently comparable to that of medical experts.
    Multimedia Tools and Applications 01/2014; · 1.01 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we propose a method to extract sternocleidomastoid and longus capitis/colli automatically and measure the thickness of those muscles from cervical vertebrae ultrasound images. Extracting sternocleidomastoid is relatively easy but for longus capitis/colli case, due to the brightness sensitivity, it requires much more computationally burdensome procedures. In the binarization process, instead of simple and cheap thresholding method, we apply fuzzy sigma binarization to mitigate the sensitivity. Since that binarization procedure is computationally expensive we keep thresholding method for sternocleidomastoid case. With considerate image processing processes such as 4-directional contour analysis and Cubic Spline interpolation, we can successfully analyze features like muscle thickness. In experiment, the efficacy of the proposed method is verified as having 73 ~ 87% of real world cervical vertebrae images successfully analyzed meaning that only a small magnitude of errors in measuring thickness from medical expert's own measurement (less than 0.1 cm for sternocleidomastoid and less than 0.3 cm for longus capitis/colli). We hope such result encourages the use of automatic ultrasound analysis system for cervical vertebrae in rehabilitation practices.
    Current Medical Imaging Reviews 01/2014; 10(2). · 0.43 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A nationwide survey was conducted of Korean urologists to illustrate physicians' perceptions and real practical patterns regarding Peyronie disease (PD). A specially designed questionnaire exploring practice characteristics and attitudes regarding PD, as well as patient satisfaction with each treatment modality, was e-mailed to 2,421 randomly selected urologists. Responses were received from 385 practicing urologists (15.9%) with a median time after certification as an urologist of 12 years. Regarding the natural course, 87% of respondents believed that PD is a progressive disease, and 82% replied that spontaneous healing in PD occurred in fewer than 20% of patients. Regarding diagnosis of PD, the methods used were, in order, history taking with physical examination (98%), International Index of Erectile Function questionnaires (40%), intracavernous injection and stimulation (35%), and duplex sonography (28%). Vitamin E was most preferred as an initial medical management (80.2%), followed by phosphodiesterase-5 inhibitors (27.4%) and Potaba (aminobenzoate potassium, 20.1%). For urologists who administered intralesional injection, the injected agent was, in order, corticosteroid (72.2%), verapamil (45.1%), and interferon (3.2%). The most frequently performed surgical procedure was plication (84.1%), followed by excision and graft (42.9%) and penile prosthesis implantation (14.2%). Among the most popular treatments in each modality, the urologists' perceptions regarding the suitability of treatment and patient satisfaction were significantly different, favoring plication surgery. The practice pattern of urologists depicted in this survey is in line with currently available Western guidelines, which indicates the need for development of further local guidelines based on solid clinical data.
    Korean journal of urology 01/2014; 55(1):57-63.
  • [Show abstract] [Hide abstract]
    ABSTRACT: According to previous studies, the prevalence of premature ejaculation (PE) in Korea ranges from 11.3% to 33%. However, the actual practice patterns in managing patients with PE is not well known. In this study, we have endeavored to determine how contemporary urologists in Korea manage patients with PE. The e-mailing list was obtained from the Korean Urological Association Registry of Physicians. A specifically designed questionnaire was e-mailed to the 2,421 urologists in Korea from May 2012 to August 2012. UROLOGISTS IN KOREA DIAGNOSED PE USING VARIOUS CRITERIA: the definition of the International Society for Sexual Medicine (63.4%), Diagnostic and Statistical Manual of Mental Disorders (43.8%), International Statistical Classification of Disease, 10th edition (61.7%), or perceptional self-diagnosis by the patient himself (23.5%). A brief self-administered questionnaire, the Premature Ejaculation Diagnostic Tool, was used by only 42.5% of the urologists. Selective-serotonin reuptake inhibitor (SSRI) therapy was the main treatment modality (91.5%) for PE patients. 40.2% of the urologists used phosphodiesterase type 5 inhibitors, 47.6% behavior therapy, and 53.7% local anesthetics. Further, 286 (54.3%) urologists managed PE patients with a surgical modality such as selective dorsal neurotomy (SDN). A majority of Korean urologists diagnose PE by a multidimensional approach using various diagnostic tools. Most urologists believe that medical treatment with an SSRI is effective in the management of PE. At the same time, surgical treatment such as SDN also investigated as one of major treatment modality despite the lack of scientific evidence.
    The world journal of men's health. 12/2013; 31(3):226-31.
  • Source
    Jung Woo Lee, Hyun Jun Park, Nam Cheol Park
    [Show abstract] [Hide abstract]
    ABSTRACT: We studied the relative importance of high-sensitivity C-reactive protein (hs-CRP) concentrations in patients with erectile dysfunction (ED) and diabetes and determined whether the hs-CRP level predicts the response to treatment with 5 mg tadalafil once daily. We enrolled 102 men (aged 40-60 years) with diabetes and ED. All patients completed the International Index of Erectile Function (IIEF) questionnaire and were given 5 mg tadalafil daily. The IIEF and serum hs-CRP levels in patients and healthy controls and in patient responders and nonresponders to 5 mg tadalafil once daily were compared. Median age was 53.2 years (range, 45 to 62 years) in patients and 55.6 years (range, 47 to 64 years) in healthy controls (p=0.158). The median duration of diabetes was 54.3 months (range, 34 to 70 months). The median IIEF and hs-CRP level were 12.1 (range, 5 to 20) and 0.21 mg/dL (range, 0.05 to 0.6 mg/dL) in patients and 28.2 (range, 13 to 31) and 0.09 mg/dL (range, 0.04 to 0.2 mg/dL) in the controls, respectively (pIIEF=0.000, pCRP=0.031). After tadalafil treatment, 71 patients (69.6%) achieved an erection sufficient for sexual intercourse, whereas 31 (30.4%) did not. The median age of the tadalafil nonresponders was 56.2 years (range, 45 to 64 years) and that of the responders was 51.3 years (range, 42 to 62 years; p=0.065). Median hs-CRP levels were 0.31 mg/dL (range, 0.18 to 0.62 mg/dL) in nonresponders and 0.14 mg/dL (range, 0.09 to 0.4 mg/dL) in responders, respectively (p=0.028). Serum hs-CRP was significantly higher in patients with ED and diabetes mellitus than in patients without ED. A significant correlation was observed between serum hs-CRP levels, the degree of ED, and responsiveness to tadalafil.
    Korean journal of urology 12/2013; 54(12):858-64.
  • [Show abstract] [Hide abstract]
    ABSTRACT: This review assesses lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH) with or without erectile dysfunction (ED) and related therapies focusing on tadalafil. A literature search was obtained and reviewed for the epidemiology, treatment therapies, pathophysiology, and efficacy and safety of phosphodiesterase type 5 inhibitor (PDE5i) tadalafil in patients with LUTS/BPH. Approximately 42% of men aged 51 to 60 years have BPH. Approximately 90% of men aged 45 to 80 years have LUTS. Occurrence of LUTS increases with age for almost all racial/ethnic groups (range, 32% to 56%) with prevalence of LUTS highest among Hispanic men, then Blacks, Caucasians, and Asians. There is an independent relationship with LUTS/BPH and ED, with approximately 70% of men with LUTS/BPH having ED with severity of one disease often correlating with the other. The European Urological Association guidelines include the use of the PDE5i tadalafil. Tadalafil is the only therapy recommended for treatment of co-existing BPH and ED, while other therapies have unwanted ED side effects. The mode of action of tadalafil may involve different areas of the lower urinary tract such as smooth muscle cell relaxation in the bladder neck, prostate, and urethra, but there may also be resulting modulation of the afferent nerve activity. Tadalafil (5 mg) in Asian men with LUTS/BPH, similar to global studies, is efficacious and safe. Tadalafil (5 mg) improves co-existing LUTS/BPH and ED, independently. Men with LUTS/BPH likely also have ED. Asian men with LUTS/BPH have similar incidence rates, co-existing ED, comorbid diseases, and risks as non-Asian men. Tadalafil can improve co-existing LUTS/BPH and ED.
    The world journal of men's health. 12/2013; 31(3):193-207.
  • [Show abstract] [Hide abstract]
    ABSTRACT: To investigate the intraocular pharmacokinetics of triamcinolone acetonide (TA) injected into the posterior subtenon of vitrectomized rabbit eyes. Vitrectomy was performed on the right eyes of 35 rabbits. Triamcinolone acetonide (40 mg/mL) was injected into the posterior subtenon space of both eyes. Five rabbits each were killed at days 1, 3, 7, 14, 28, 56, and 84. Both eyes were enucleated. The vitreous was isolated, and TA concentration was measured. In vitrectomized eyes, the intravitreal concentrations of TA were 1763, 822.9, 321.5, 113.3, 35.5, 14.4, and 6.7 ng/mL, respectively, at the time points indicated above; the concentrations in nonvitrectomized eyes were 397.8, 360.4, 154.4, 48.5, 30.7, 15.2, and 8.0 ng/mL, respectively. Triamcinolone acetonide concentrations were significantly higher in the vitrectomized eyes at days 1, 3, 7, and 14. The terminal half-life of intravitreal TA was 23.3 days in the vitrectomized eyes and 28.9 days in the nonvitrectomized eyes. Intravitreal absorption and excretion of TA in the posterior subtenon space are increased after vitrectomy. Although the terminal half-life of TA was shorter, higher early concentration and similar effective duration were achieved in the vitrectomized eyes.
    Retina (Philadelphia, Pa.) 09/2013; · 2.93 Impact Factor
  • Source
    Sungmin Kang, Hyun Jun Park, Nam Cheol Park
    [Show abstract] [Hide abstract]
    ABSTRACT: Late-onset hypogonadism (LOH) in aging males is a clinical and biochemical syndrome characterized by a decline in serum testosterone levels. LOH results in various physical and mental disabilities. We evaluated the relationship between serum testosterone levels and symptoms of LOH. During an andropause screening program, we examined responses to the Saint Louis university androgen deficiency in aging males (ADAM) questionnaire and results on the International Index of Erectile Function (IIEF-5) in terms of clinical symptoms and evaluated serum total testosterone levels for a biochemical diagnosis of LOH in healthy community-living volunteers aged over 40 years. The mean age of the 534 men was 59.1 years (range, 40 to 79 years), and their mean serum testosterone level was 464.1±171.9 ng/dL. The serum testosterone level decreased significantly with age. There was a 92.5% positive response rate to the ADAM questionnaire. The percentage of patients whose serum testosterone level was <350 ng/dL among those with a positive response to the ADAM questionnaire was 25.6% (137 patients). The mean serum testosterone level among patients with a positive or negative ADAM questionnaire was 472.4±198.5 ng/dL and 487.3±165.7 ng/dL, respectively (p>0.05). There was no significant correlation between IIEF-5 scores and serum testosterone levels. Among men over 40 years of age, 25.6% met the clinical and biochemical diagnostic criteria for LOH. There was no relationship between serum testosterone levels and symptoms of LOH.
    Korean journal of urology 09/2013; 54(9):619-23.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We analyzed factors associated with early recovery of continence after laparoscopic radical prostatectomy. Among 467 patients treated with laparoscopic radical prostatectomy for localized prostate cancer between 2007 and 2012, 249 patients who underwent a preoperative urodynamic study were enrolled. The patients' age, prostate volume, preoperative serum prostate-specific antigen (PSA), Gleason score, pathologic stage, and preoperative urodynamic parameters were recorded. The preoperative membranous and prostatic urethral length on magnetic resonance image, nerve sparing technique, and type of surgical procedure (extrafascial and intrafascial) were analyzed. Patients were considered to have early recovery of continence when they needed no pad in 3 months or less after surgery. Ninety-two patients were in the early recovery group and 157 were in the late recovery group. The membranous urethral lengths were 12.06±2.56 and 11.81±2.87 mm, and prostatic urethral lengths were 36.39±6.15 and 37.45±7.55 mm in each group, respectively. The membranous-posterior urethral length ratios were 0.25±0.06 and 0.24±0.06, and prostatic-posterior urethral length ratios were 0.75±0.06 and 0.76±0.06, respectively. In and of themselves, the membranous and prostatic urethral lengths were not associated with recovery duration however, the membranous-total and prostatic-total urethral length ratios were related (p=0.024 and 0.024, respectively). None of the urodynamic parameters correlated with continence recovery time. In the multivariate analysis, the type of surgical procedure (odds ratio [OR], 7.032; 95% confidence interval [CI], 2.660 to 18.590; p<0.001) and membranous urethral length (OR, 0.845; 95% CI, 0.766 to 0.931; p=0.001) were significantly related to early recovery of continence. The current intrafascial surgical procedure is the most important factor affecting early recovery of continence after laparoscopic radical prostatectomy.
    The world journal of men's health. 08/2013; 31(2):163-9.
  • Source
    Nam Cheol Park, Tae Nam Kim, Hyun Jun Park
    [Show abstract] [Hide abstract]
    ABSTRACT: Currently, phosphodiesterase type 5 (PDE5) inhibitors are the initial treatment option for erectile dysfunction. The reported efficacy of PDE5 inhibitors is about 70%, although it is significantly lower in difficult-to-treat subpopulations. Treatment failures might be due to the severity of the underlying pathophysiology, improper use of medication, unrealistic patient expectations, difficult relationship dynamics, severe performance anxiety, and other psychological problems. Physicians must address these issues to identify true treatment failures attributable to the drugs. This article discusses factors that might affect the response to PDE5 inhibitors and develops a strategy to maximize the overall efficacy of PDE5 inhibitors in initial non-responders to PDE5 inhibitors.
    The world journal of men's health. 04/2013; 31(1):31-5.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Intratesticular cysts, once thought to be a rarity, are now being reported with an increasing prevalence as a result of the wider use of scrotal ultrasound scanning. Despite greater understanding of intratesticular cysts, their management remains unclear. Treatment has included enucleation and even radical orchiectomy over fear of the possibility of an associated malignancy. A more conservative approach with serial ultrasound scanning has been advocated if a clear distinction can be made between neoplastic and non-neoplastic testicular cysts. However, in view of the benign nature of such cysts, even repeated ultrasound scanning may not be necessary and may be considered over-treatment. In this study we present clinical and morphological characteristics of multiple cysts in the right testicle in a 62-year-old patient, where a slightly nodular lesion in the right testicle was detected.
    The world journal of men's health. 04/2013; 31(1):79-82.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this study was to report a case of acute retinal necrosis (ARN) after intraocular foreign body removal. A 32-year-old male presented with visual loss in the left eye. He was hit by an iron fragment while he was hammering. An intraocular foreign body was found with corneal laceration and traumatic cataract. On the day he was injured, primary closure of the laceration, lensectomy, and vitrectomy were performed, and the foreign body was removed. The day after the operation, there was no sign of retinal detachment or retinitis. Two days after the operation, retinal necrosis and accompanying vitreous inflammation were noted in the far periphery. On day 3, the necrosis spread circumferentially and inflammation became more distinct. ARN was presumed and intravenous acyclovir was administered. The necrotic areas were reduced 2 days later, and were resolved in 1 month. The final visual acuity in his left eye was 20/20 after implantation of an intraocular lens. This case is the first report of ARN after penetrating injury and an intraocular foreign body. ARN may develop after open-globe injury.
    Clinical ophthalmology (Auckland, N.Z.) 01/2013; 7:545-8.
  • [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND: The probability of a prostate cancer-positive biopsy result varies with PSA concentration. Thus, we applied information theory on classification and regression tree (CART) analysis for decision making predicting the probability of a biopsy result at various PSA concentrations. METHODS: From 2007 to 2009, prostate biopsies were performed in 664 referred patients in a tertiary hospital. We created 2 CART models based on the information theory: one for moderate uncertainty (PSA concentration: 2.5-10ng/ml) and the other for high uncertainty (PSA concentration: 10-25ng/ml). RESULTS: The CART model for moderate uncertainty (n=321) had 3 splits based on PSA density (PSAD), hypoechoic nodules, and age and the other CART for high uncertainty (n=160) had 2 splits based on prostate volume and free PSA. In this validation set, the patients (14.3% and 14.0% for moderate and high uncertainty groups, respectively) could avoid unnecessary biopsies without false-negative results. CONCLUSIONS: Using these CART models based on uncertainty information of PSA, the overall reduction in unnecessary prostate biopsies was 14.0-14.3% and CART models were simplified. Using uncertainty of laboratory results from information theoretic approach can provide additional information for decision analysis such as CART.
    Clinica chimica acta; international journal of clinical chemistry 10/2012; · 2.54 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND AND OBJECTIVE:To investigate the findings of a tissue layer image of the photoreceptor layer, or photoreceptor layer map (PLM), using spectral-domain optical coherence tomography (SD-OCT) in central serous chorioretinopathy (CSC). PATIENTS AND METHODS:Data scanned using SD-OCT in CSC were processed to obtain PLMs, which were analyzed and compared with fluorescein angiography and OCT. RESULTS:Among 72 eyes of 69 patients, PLMs depicted subretinal fluid as distinct hyporeflective areas in 71 eyes (98.6% sensitivity). Attenuated signals at the junction of the inner and outer segments of the photo-receptors in OCT were depicted as relative hyporeflective areas corresponding to the areas of previous subretinal fluid and its recent reduction. After resolution of subretinal fluid, foveal reflectivity was correlated with visual acuity (P = .040; r = 0.41). CONCLUSION:PLM is a useful adjuvant image for managing CSC because it shows the photoreceptor layer and subretinal fluid as a fundus image.
    Ophthalmic Surgery Lasers and Imaging 09/2012; · 1.46 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Torsion of a hernia sac is an extremely rare condition that presents as acute scrotum in children. We report a case of a 6-year-old boy who presented with an acute scrotum and was found during surgical exploration to have torsion of an indirect hernia sac associated with hydrocele. Upon scrotal exploration, deterioration of the scrotum due to inflammatory changes was found. A necrotic cyst was recognized within a communicating hydrocele of the scrotum and was twisted at an angle of about 360°. All urologists should be aware of this special condition in the differential diagnosis of acute scrotum.
    The world journal of men's health. 08/2012; 30(2):150-2.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To investigate the effect of prostaglandin F2α (PGF2α), latanoprost, travoprost, bimatoprost, and tafluprost on human orbital preadipocyte differentiation and intracellular lipid storage, and to reveal the potential mechanisms by which topical prostaglandin analogs induce orbital fat volume reduction and cause deep superior sulcus syndrome. Human orbital adipose precursors were treated in vitro for 24 h (day 1) with PGF2α, latanoprost, travoprost, bimatoprost, and tafluprost in their commercial formulations (1:100 dilution). Expressions of adipogenic transcription factor, peroxisome proliferator-activated receptor-gamma (PPARγ), and CCAAT-enhancer-binding protein α (C/EBPα) were determined by real-time reverse transcription-polymerase chain reaction (RT-PCR) at day 7. At 14 days, cells were stained with oil red O, intracellular lipid accumulation was evaluated by lipid absorbance, and adipocyte expression marker [Lipoprotein lipase (LPL)] was determined by real-time RT-PCR. Our results showed that PGF2α and topical prostaglandin analogs down-regulated the expression of PPARγ and C/EBPα, and inhibited accumulation of intra-cytoplasmic lipid droplets and expression of LPL compared with the untreated control. Comparison between the 4 drugs showed that latanoprost had the weakest antiadipogenic effect, and bimatoprost induced the most significant reduction of adipogenesis. Latanoprost, travoprost, bimatoprost, and tafluprost inhibited human preadipocyte differentiation and intracellular lipid accumulation. Morphologic and metabolic changes in orbital adipocytes caused by PGF2α analogs are a possible pathophysiologic explanation of superior eyelid deepening in patients with glaucoma.
    Journal of ocular pharmacology and therapeutics: the official journal of the Association for Ocular Pharmacology and Therapeutics 11/2011; 28(2):146-52. · 1.46 Impact Factor