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Dive into the research topics where Ricardo Miyaoka is active.

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Featured researches published by Ricardo Miyaoka.


Clinics | 2011

An update on the clinical assessment of the infertile male

Sandro C. Esteves; Ricardo Miyaoka; Ashok Agarwal

Male infertility is directly or indirectly responsible for 60% of cases involving reproductive-age couples with fertility-related issues. Nevertheless, the evaluation of male infertility is often underestimated or postponed. A coordinated evaluation of the infertile male using standardized procedures improves both diagnostic precision and the results of subsequent management in terms of effectiveness, risk and costs. Recent advances in assisted reproductive techniques (ART) have made it possible to identify and overcome previously untreatable causes of male infertility. To properly utilize the available techniques and improve clinical results, it is of the utmost importance that patients are adequately diagnosed and evaluated. Ideally, this initial assessment should also be affordable and accessible. We describe the main aspects of male infertility evaluation in a practical manner to provide information on the judicious use of available diagnostic tools and to better determine the etiology of the most adequate treatment for the existing condition.


International Braz J Urol | 2011

Sperm retrieval techniques for assisted reproduction.

Sandro C. Esteves; Ricardo Miyaoka; Ashok Agarwal

Different surgical methods such as PESA, MESA, TESA, TESE and micro-TESE have been developed to retrieve spermatozoa from either the epididymis or the testis according to the type of azoospermia, i.e., obstructive or non-obstructive. Laboratory techniques are used to remove contaminants, cellular debris, and red blood cells following collection of the epididymal fluid or testicular tissue. Surgically-retrieved spermatozoa may be used for intracytoplasmic sperm injection (ICSI) and/or cryopreservation. In this article, we review the surgical procedures for retrieving spermatozoa from both the epididymis and the testicle and provide technical details of the commonly used methods. A critical analysis of the advantages and limitations of the current surgical methods to retrieve sperm from males with obstructive and non-obstructive azoospermia is presented along with an overview of the laboratory techniques routinely used to process surgically-retrieved sperm. Lastly, we summarize the results from the current literature of sperm retrieval, as well as the clinical outcome of ICSI in the clinical scenario of obstructive and nonobstructive azoospermia.


Advances in Urology | 2012

A critical appraisal on the role of varicocele in male infertility.

Ricardo Miyaoka; Sandro C. Esteves

Varicocele is a major cause of male infertility, as it may impair spermatogenesis through several distinct physiopathological mechanisms. With the recent advances in biomolecular techniques and the development of novel sperm functional tests, it has been possible to better understand the mechanisms involved in testicular damage provoked by varicocele and, therefore, propose optimized ways to prevent and/or reverse them. Up to now, there is still controversy involving the true benefit of varicocele repair in subfertile men as well as in certain specific situations such as concomitant contralateral subclinical varicocele or associated nonobstructive azoospermia. Also, with the continued development of assisted reproductive technology new issues and questions are emerging regarding the role of varicocelectomy in this context. This paper reviews the most recent data available on the pathogenesis, diagnosis, and management of varicocele with regard to male infertility.


Neurourology and Urodynamics | 2010

Pelvic Floor Muscle Training in the Treatment of Lower Urinary Tract Dysfunction in women with Multiple Sclerosis

Adélia Correia Lúcio; Renata Martins Campos; Maria Carolina Perissinotto; Ricardo Miyaoka; Benito Pereira Damasceno; Carlos Arturo Levi D'Ancona

Evaluate the role of Pelvic Floor Muscle Training (PFMT) on the treatment of Lower Urinary Tract Dysfunction (LUTD) in Multiple Sclerosis (MS) patients.


Asian Journal of Andrology | 2016

Outcome of varicocele repair in men with nonobstructive azoospermia: systematic review and meta-analysis.

Sandro C. Esteves; Ricardo Miyaoka; Matheus Roque; Ashok Agarwal

The objective of this systemic review was to evaluate the benefit of repairing clinical varicocele in infertile men with nonobstructive azoospermia (NOA). The surgically obtained sperm retrieval rate (SRR) and pregnancy rates following assisted reproductive technology (ART) with the use of retrieved testicular sperm were the primary outcomes. The secondary outcomes included the presence of viable sperm in postoperative ejaculate to avoid the testicular sperm retrieval and pregnancy rates (both assisted and unassisted) using postoperative ejaculated sperm. An electronic search to collect the data was performed using the MEDLINE and EMBASE databases until April 2015. Eighteen studies were included in this systematic review and accounted for 468 patients who were diagnosed with NOA and varicocele. These patients were subjected to either surgical varicocele repair or percutaneous embolization. Three controlled studies evaluating sperm retrieval outcomes indicated that in patients who underwent varicocelectomy, SRR increased compared to those without varicocele repair (OR: 2.65; 95% CI: 1.69-4.14; P< 0.001). Although pregnancy rates with the use of testicular sperm favored the varicocelectomy group, results were not statistically significant (clinical pregnancy rate OR: 2.07; 95% CI: 0.92-4.65; P= 0.08; live birth rate OR: 2.19; 95% CI: 0.99-4.83; P= 0.05). The remaining fifteen studies reported postoperative semen analysis results. In 43.9% of the patients (range: 20.8%-55.0%), sperm were found in postoperative ejaculates. Pregnancy rates for unassisted and assisted (after IVF/ICSI) were 13.6% and 18.9% in the group of men with sperm in postoperative ejaculates, respectively. Our findings indicate that varicocelectomy in patients with NOA and clinical varicocele is associated with improved SRR. In addition, approximately 44% of the treated men will have enough sperm in the ejaculate to avoid sperm retrieval. Limited data on pregnancy outcomes with both postoperative ejaculated sperm and harvested testicular sperm preclude any firm conclusion with regard to the possible increased fertility potential in treated individuals. In conclusion, the results of our study indicate that infertile men with NOA and clinical varicocele benefit from varicocelectomy.  Given the low/moderate quality of evidence available, it is advisable that doctors discuss with their patients with NOA the risks and benefits of varicocele repair.


International Braz J Urol | 2004

RESINIFERATOXIN FOR DETRUSOR INSTABILITY REFRACTORY TO ANTICHOLINERGICS

Paulo Palma; Marcelo Thiel; Cassio Riccetto; M. Dambros; Ricardo Miyaoka; N. Rodrigues Netto

PURPOSE We have evaluated the clinical and urodynamic effects of intravesical instillation of resiniferatoxin in patients with idiopathic detrusor instability refractory to anticholinergics. MATERIALS AND METHODS There were 30 women, median age 56 years old with detrusor instability for over 6 months and a history of anticholinergic use with no response or intolerable collateral effects. A 50 nM solution of resiniferatoxin was prepared for intravesical instillation. All patients were evaluated for urinary symptoms, as well as for urodynamic assessments before and 30 days after instillation. Tolerability was analyzed during the instillation. RESULTS A clinical improvement was observed in 30% of the patients with urinary urgency and in 33% of the patients with urge-incontinence. The mean maximum cystometric capacity before application was 303.9 +/- 78.9 and after application 341 +/- 84.6. No significant difference was observed (p = 0.585). The mean maximum amplitude of the contractions diminished from 47.86 +/- 29.64 to 38.72 +/- 30.77 (p = 0.002). CONCLUSIONS Resiniferatoxin, in this concentration, proved to be useful in a small percentage of patients regarding clinical detrusor instability. Maximum amplitude of the involuntary contractions was significantly reduced and in 33% patients the involuntary contractions disappeared. Further studies with different concentrations are recommended.


Journal of Endourology | 2012

Correlation between stress and kidney stone disease.

Ricardo Miyaoka; Omar Ortiz-Alvarado; Carly Kriedberg; Shaheen Alanee; Ekkarin Chotikawanich; Manoj Monga

BACKGROUND AND PURPOSE Prevalence of kidney stone disease is increasing worldwide, and several factors may be involved. We aimed to establish a correlation between stress and kidney stones. PATIENTS AND METHODS We prospectively evaluated 200 patients with a diagnosis of kidney stone disease having them self-respond to a validated questionnaire to measure stress (Perceived Stress Scale-10 [PSS-10]). Stone-related characteristics and potential stressing factors were assessed. Variables that were significant on the univariate analysis were used to construct a model that was able to explain the variability in PSS-10 score in our patients. RESULTS Mean PSS-10 score was 15.3 ± 1.1. Female sex (P=0.014), occurrence of death or serious illness of a family member or close friend within the last 6 months of the interview (P=0.044), occurrence of other psychological trauma (P<0.0001) all proved to be significant factors. Stone-related aspects associated with stress were presence of symptoms at the time of the interview (P=0.012) and passage of two or more stones per year (P=0.022). We were able to construct a model that explains 34% of the variability of the PSS-10 between subjects. Employment status was the only significant variable, but sex, age, and presence of symptoms at the time of questionnaire administration had to be kept in to achieve a model that explains the largest variability. CONCLUSIONS Passage of two or more stones per year and presence of symptoms proved to be factors related to elevated stress in patients with a diagnosis of kidney stone disease. Female sex, age, and unemployment may also contribute to a stressed state in this population.


International Braz J Urol | 2012

Laparoscopic treatment of lymphoceles after renal transplantation

Marcelo Lopes de Lima; Cristiano Augusto Calderaro Cotrim; Juliano Cesar Moro; Ricardo Miyaoka; Carlos Arturo Levi D'Ancona

OBJECTIVE Lymphocele formation following renal transplantation is a frequent complication and may affect as many as 49% of patients. Operative treatment of symptomatic post transplant lymphocele (PTL) consists of wide drainage of the fluid collection into the abdominal cavity by excising its wall, connecting the lymphocele cavity to the intraperitoneal space. Laparoscopic fenestration seems to be the best treatment as it combines satisfying success rates with a minimally invasive approach. The aim of the study was to review a single center experience on the laparoscopic treatment of symptomatic PTL and detail relevant aspects of the surgical technique. MATERIALS AND METHODS The data of 25 patients who underwent laparoscopic surgical treatment for a symptomatic lymphocele following kidney transplantation were retrospectively reviewed. Demographic data and surgical results were assessed. Detailed surgical technique is provided. RESULTS Between 1996 and 2008, 991 patients received a kidney transplant at our institution. Twenty-five patients (2.52%) developed a symptomatic lymphocele and laparoscopic drainage was performed. The indications for surgical drainage were graft dysfunction (84%), local symptoms (16%) or both (32%). The mean time until surgical therapy was 14.2 ± 6 weeks. Mean hospital stay was 1.5 ± 0.2 days. Postoperative complications occurred in only 2 patients (8%) (one ureteral injury and one incisional hernia) and required reoperation. After a mean followup of 36.2 ± 4 months, only 1 patient had a symptomatic recurrence. CONCLUSIONS Laparoscopic fenestration is an effective surgical technique to treat symptomatic lymphocele following kidney transplantation with low recurrence rate and long standing results.


Clinics | 2013

Predictive factors for sperm retrieval and sperm injection outcomes in obstructive azoospermia: do etiology, retrieval techniques and gamete source play a role?

Ricardo Miyaoka; Sandro C. Esteves

Obstructive azoospermia is a relatively common male infertility condition. The main etiologies of obstructive azoospermia include congenital, surgical-derived, traumatic and post-infectious cases. Although seminal tract reconstruction is a cost-effective treatment in most cases, this approach may not be feasible or desired in some cases. In such cases, assisted reproduction techniques offer a method for achieving pregnancy, notably via sperm retrieval and intracytoplasmic sperm injection. This process requires several considerations and decisions to be made, including the cause and duration of obstruction, which sperm retrieval technique to use, and whether to use fresh or frozen-thawed sperm. We present a review of obstructive azoospermia and assisted reproduction techniques, highlighting the most relevant aspects of the decision-making process for use in clinical practice.


Biofouling | 2013

Understanding urinary conditioning film components on ureteral stents: profiling protein components and evaluating their role in bacterial colonization

Chelsea N. Elwood; Joey Lo; Emily Chou; Adam M. Crowe; Olga Arsovska; Hans Adomat; Ricardo Miyaoka; Emma Tomlinson-Guns; Manoj Monga; Ben H. Chew; Dirk Lange

Ureteral stents are fraught with problems. A conditioning film attaches to the stent surface within hours of implantation; however, differences between stent types and their role in promoting encrustation and bacterial adhesion and colonization remain to be elucidated. The present work shows that the most common components do not differ between stent types or patients with the same indwelling stent, and contain components that may drive stent encrustation. Furthermore, unlike what was previously thought, the presence of a conditioning film does not increase bacterial adhesion and colonization of stents by uropathogens. Genitourinary cytokeratins are implicated in playing a significant role in conditioning film formation. Overall, stent biomaterial design to date has been unsuccessful in discovering an ideal coating to prevent encrustation and bacterial adhesion. This current study elucidates a more global understanding of urinary conditioning film components. It also supports specific focus on the importance of physical characteristics of the stent and how they can prevent encrustation and bacterial adhesion.

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Cassio Riccetto

State University of Campinas

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Paulo Palma

State University of Campinas

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Sandro C. Esteves

State University of Campinas

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R. Fraga

State University of Campinas

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C. Riccetto

State University of Campinas

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P. Palma

State University of Campinas

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