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Biomedical subjects

Y Yamada

Publications and source records attributed to Y Yamada.

At least 217 records · Page 12Linked to original sources
PubMed2001

An anterior urethral stitch improves urinary incontinence following radical prostatectomy.

OBJECTIVE: To determine the effects of an anterior urethral stitch, referred to as an endopelvic anterior urethral stitch (EAUS), in reducing recovery time for post-prostatectomy urinary incontinence. METHODS: The urinary continence recovery time for 24 patients, who received a retropubic radical prostatectomy with the EAUS procedure, was compared to that of a historical control series of 22 patients without EAUS. The EAUS is a simple 2-0 polyglactin stitch placed between the bunched dorsal vein complex and the anterior urethra. This procedure was performed at the time of urethro-vesical anastomosis. Continence recovery time was defined as the day after removal of the urethral catheter when the patient no longer required pads for incontinence. RESULTS: A significantly shorter time for continence recovery (median 8.5 days) was obtained in EAUS patients compared with that of the control series (median 72 days) (P < 0.0001). Early recovery of continence was observed in 12/24 patients (50%) within 1 week and 18/24 patients (75%) within 1 month in EAUS patients. No adverse effects or complications were observed in the EAUS patients. CONCLUSION: A surgical procedure, the EAUS, has been developed that reduces urinary incontinence in patients who have undergone a radical prostatectomy. This procedure is simple and quick and improves recovery of continence without any side-effects.

Aged↗
PubMed2001

Holmium:YAG laser endoureterotomy in the treatment of ureteroenteric stricture following Indiana urinary diversion.

A 57-year-old man who had received radical urethrocystectomy and Indiana urinary diversion 6 months earlier was treated for ureteroenteric anastomosis stricture (left side) using a Holmium:YAG laser via antegrade approach. The availability of small (6.9 Fr) flexible ureteroscope, as well as the use of the Holmium:YAG laser has facilitated the ability to precisely incise the stricture under direct endoscopic visualization. The technique is described for laser endoureterotomy in a patient with ureteroenteric stricture following Indiana urinary diversion.

Anastomosis, Surgical↗
PubMed2001

Endoscopic ureteral incision using the holmium:YAG laser.

BACKGROUND: We reviewed the results of endoscopic ureteral incision for benign ureteral stricture, ureteropelvic junction obstruction and ureteroenteroanastomotic stricture using the holmium laser. METHODS: We carried out endoscopic ureteral incision using the holmium laser through an 8-Fr semirigid or 6.9-Fr flexible ureteroscope on 17 ureters in 15 patients. Balloon dilatation was not necessary before insertion of the ureteroscope. The stricture was incised with the holmium laser using a 200-365 microm fiber through the working channel of the ureteroscope. After completion of the incision, a 12-Fr double-J catheter was left for 6 weeks. Thereafter patients were followed by renal scan and/or ultrasound and excretory urography at 3-6 month intervals. RESULTS: The mean operative time was 65 min (18-135 min). The stricture resolved completely in 86.7% of cases at an average follow up of 20.5 months (11-32 months). CONCLUSIONS: The holmium laser endoscopic ureteral incision was associated with a good outcome in our series. We recommend this procedure to be employed initially because it is less invasive and has a favorable outcome.

Adult↗
PubMed2001

Clinical study of transitional cell carcinoma of the prostate associated with bladder transitional cell carcinoma.

BACKGROUND: Transitional cell carcinoma of the prostate in patients with bladder cancer appears to influence the prognosis and affects the decision about therapeutic modality. Therefore, it is important to characterize transitional cell carcinoma associated with bladder cancer. METHODS: From April 1980 to December 1998, 81 male patients underwent total cystoprostatectomies for transitional cell carcinoma of the bladder. The 81 cystoprostatectomy specimens were examined to clarify the characteristics of prostatic involvement by transitional cell carcinoma. The extent, origin, mode of spread and risk factor of prostatic involvement as well as the prognosis were investigated. In 13 of 15 patients with prostatic involvement the prostate was examined by sequential step sections. RESULTS: Prostatic involvement was observed in 15 of 81 patients (18.5%). Prostatic urethral involvement, invasion to prostatic duct/acinus, prostatic stromal invasion and extraprostatic extension and/or seminal vesicle involvement were recognized in 12 (80%), 14 (93.3%), six (40%), and five (33.3%) of the 15 patients, respectively. Twelve of the 15 patients (80%) with prostatic involvement had papillary or non-papillary tumors (i.e. carcinoma in situ) both in the prostatic urethra and prostatic duct. In 10 of these 12 patients (88.3%), there was contiguity between prostatic urethral and ductal tumors. Seven of the 23 patients (30.4%) with carcinoma in situ of the bladder showed prostatic involvement, which increased to 50% in the presence of carcinoma in situ of the trigone or bladder neck. CONCLUSIONS: Eighty per cent of the patients with prostatic involvement showed papillary or non-papillary tumors both in the prostatic urethra and prostatic duct. There was a high level of contiguity between both tumors. Patients with carcinoma in situ of the trigone or bladder neck revealed significantly higher incidence of prostatic involvement.

Carcinoma in Situ↗
PubMed2001

Will accident reports filed in hospitals in Japan be used in the future as evidence in malpractice lawsuits?

A major drawback of submission of so-called incident reports for medical institutions is that such reports may be able to be obtained on request by patients and to be used as evidence in malpractice lawsuits. In Japan, there are no established rules concerning the use of accident reports in medical lawsuits. More debate is needed for voluntary report systems to become established in medical institutions throughout Japan.

Disclosure↗
PubMed2001

Mechanism of retarded liver regeneration in plasminogen activator-deficient mice: impaired activation of hepatocyte growth factor after Fas-mediated massive hepatic apoptosis.

Urokinase-type plasminogen activator (uPA) is implicated in the regulation of hepatic regeneration by activating hepatocyte growth factor (HGF). Here, we investigated its role in the hepatic regeneration after Fas-mediated massive hepatocyte death employing mice deficient in either uPA or its inhibitor, plasminogen activator inhibitor-1 (PAI-1). We measured kinetics of hepatic levels of proliferating cell nuclear antigen (PCNA)-labeling index, plasmin activity, mature HGF, and its phosphorylated receptor, c-Met. In the genetically targeted and wild-type mice, hepatocytes fell into the same extent of apoptosis 6 to 12 hours after an intraperitoneal injection with anti-Fas antibody, as judged from histologic analysis and a histon-DNA enzyme-linked immunosorbent assay (ELISA). In the wild-type mice, mature HGF emerged in the liver 6 hours following anti-Fas injection, and hepatic PCNA-labeling index started to increase following 24 hours and peaked at 48 hours. In the uPA(-/-) mice, emergence of mature HGF was delayed 12 hours and hepatic regeneration peaked at 96 hours. Supplementation with the uPA gene to the uPA(-/-) mice by in vivo lipofection restored hepatic plasmin levels, and improved a delay in the expression of both mature HGF and phosphorylated c-Met, accompanying a normal rate of liver regeneration. In contrast, PAI-1(-/-) mice showed accelerated liver regeneration; mature HGF emerged as early as 3 hours, and PCNA-labeling index increased at 24 hours. This accelerated regeneration was abolished by administration with anti-HGF antibody. These results strongly suggest a physiologic role of uPA in the proteolytic maturation of HGF, and thereby in hepatic regeneration after Fas-mediated massive hepatocyte death.

Animals↗
PubMed2001

Relationship between osteoprotegerin/osteoclastogenesis inhibitory factor concentration in synovial fluid and disease severity in individuals with osteoarthritis of the knee.

We studied the relationship between osteoprotegerin (OPG)/osteoclastogenesis inhibitory factor (OCIF) concentration in synovial fluid from individuals with osteoarthritis (OA) of the knee and the severity of this condition. The study population included 111 Japanese women with knee OA (153 knees) and 23 normal controls. Osteoarthritic changes were graded according to the system of Kellgren and Lawrence. The concentration of OPG/OCIF in synovial fluid increased with severity of knee OA and was significantly higher in individuals with OA of grade IV than in those with OA of grade 0 or grade 1. It has been shown in a previous study that administration of OPG/OCIF prevents cartilage destruction in adjuvant-induced arthritis in rats. The increase in the concentration OPG/OCIF in synovial fluid of individuals with knee OA might thus reflect a compensatory response to degeneration of articular cartilage and serve to protect cartilage rather than be a cause of OA.

Aged↗
PubMed2001

Cytokines in pleural liquid for diagnosis of tuberculous pleurisy.

An elevated level of adenosine deaminase (ADA) in pleural liquid has been considered as a supplemental diagnostic marker for tuberculous pleurisy. However, this is complicated by false-positives and -negatives. Recently, it has been revealed that various cytokines are intimately involved in the pathognomonic physiology of tuberculosis. In this study, interleukin-8 (IL-8), tumour necrosis factor alpha (TNFalpha) and interferon gamma (IFNgamma) were compared with ADA in pleural liquid of patients with inflammatory (21 cases), malignant (28 cases) and tuberculous (21 cases) disease. The pleural ADA, IL-8, TNFalpha and IFNgamma levels in the tuberculous group were higher than in the other three groups. Analysis of receiver operating characteristic (ROC) curves, to evaluate the utility of the various parameters, demonstrates values for the area under the curve (AUC) of 0.770, 0.875, 0.892 and 0.987, respectively for IL-8, TNFalpha, ADA and IFNgamma. No false-positives were encountered with IFNgamma and only one case with a small volume of pleural liquid was a false-negative. This indicates that IFNgamma is a very reliable marker of tuberculous pleurisy.

Adenosine Deaminase↗
PubMed2001

Genetic variation in the hepatocyte nuclear factor (HNF)-3alpha gene does not contribute to maturity-onset diabetes of the young in Japanese.

Heterozygous mutations in the genes encoding transcription factors in the hepatocyte nuclear factor (HNF) cascade are associated with maturity-onset diabetes of the young (MODY), a monogenic form of diabetes mellitus. However, these genes are responsible for only approximately 20% of the cases of MODY in Japanese patients. Searching for a novel MODY gene in this population, we investigated a candidate for encoding the forkhead transcription factor HNF-3alpha, which also belongs to the HNF-transcription cascade. The human HNF-3alpha gene, which was assigned to the segment near microsatellites D14S75 and AFM200ZH4 on chromosome 14 by radiation hybrid mapping, spans approximately 5 kb and consists of two exons. Ninety-five Japanese subjects with MODY/early-onset non-ketotic diabetes were screened for mutations in this gene. Direct sequencing of the exons and flanking regions identified one missense mutation (Ala-83-Thr) in exon 2 and three nucleotide alterations in the non-coding regions. However, their frequencies were not significantly different between MODY and control subjects, indicating that mutations in the HNF-3alpha gene are not a major cause of MODY in Japanese patients.

DNA-Binding Proteins↗
PubMed2001

Melanin and blood concentration in human skin studied by multiple regression analysis: experiments.

Knowledge of the mechanism of human skin colour and measurement of melanin and blood concentration in human skin are needed in the medical and cosmetic fields. The absorbance spectrum from reflectance at the visible wavelength of human skin increases under several conditions such as a sunburn or scalding. The change of the absorbance spectrum from reflectance including the scattering effect does not correspond to the molar absorption spectrum of melanin and blood. The modified Beer-Lambert law is applied to the change in the absorbance spectrum from reflectance of human skin as the change in melanin and blood is assumed to be small. The concentration of melanin and blood was estimated from the absorbance spectrum reflectance of human skin using multiple regression analysis. Estimated concentrations were compared with the measured one in a phantom experiment and this method was applied to in vivo skin.

Biophysical Phenomena↗
PubMed2001

Melanin and blood concentration in a human skin model studied by multiple regression analysis: assessment by Monte Carlo simulation.

Measurement of melanin and blood concentration in human skin is needed in the medical and the cosmetic fields because human skin colour is mainly determined by the colours of melanin and blood. It is difficult to measure these concentrations in human skin because skin has a multi-layered structure and scatters light strongly throughout the visible spectrum. The Monte Carlo simulation currently used for the analysis of skin colour requires long calculation times and knowledge of the specific optical properties of each skin layer. A regression analysis based on the modified Beer-Lambert law is presented as a method of measuring melanin and blood concentration in human skin in a shorter period of time and with fewer calculations. The accuracy of this method is assessed using Monte Carlo simulations.

Biophysical Phenomena↗
PubMed2001

Treatment of lymphangioma with Nd:YAG laser irradiation: a case report.

OBJECTIVE: In this case report, the treatment of a buccal lymphangioma in a 9-year-old female was done using the Nd:YAG laser and the clinical outcome was evaluated. BACKGROUND DATA: The treatment of lymphangioma with the laser surgery using Nd:YAG and CO2 laser has become favorable due of a lack of postoperative pain and hemorrhage. METHODS: The lesion was treated with a pulsed Nd:YAG laser (d-lase 300, American Dental Laser, Detroit, MI). An exposure of 10 min each was performed at an interval of 10 days by the noncontact method with the energy density of 1 W, 10 Hz. RESULTS: It was observed that there was a great reduction of the lesion and a considerable reduction of the external facial volume. As the excision of the lesion was avoided in our present study, there was no pain and hemorrhage. A remarkable reduction of the tumor size could be observed visually within the five laser exposures. CONCLUSIONS: It can be concluded that if Nd:YAG laser therapy is used for reducing the tumor size as a primary treatment, the operation becomes easy and the recurrence may be less than with the conventional treatment, and an option of a surgical or laser excision could be reserved.

Child↗
PubMed2001

Comparison between the removal effect of mechanical, Nd:YAG, and Er:YAG laser systems in carious dentin.

OBJECTIVE: The purpose of this study was to compare the effectiveness of carious dentin removal by using an Er:YAG laser irradiation and Nd:YAG laser under a continuous water spray with that of the conventional mechanical treatment in vitro. BACKGROUND DATA: Lasers are being considered as a potential replacement of conventional mechanical systems to remove diseased and healthy dental hard tissues. METHODS: First, one half of the 10 carious lesions were treated with the round steel bur and then removed. The other half were treated with the Er:YAG laser at 200-mJ pulse energy at 2 Hz. After that, one half of another set of 10 teeth was subjected to the round steel bur in which the other half was removed using the Nd:YAG laser at 6-W output power, 20 pps, and under a continuous water spray (120 mL/min). Thermal change during each treatment and the time required for carious dentin removal was determined, and the surface characteristic was observed using the scanning electron microscopic (SEM). RESULTS: The Er:YAG or Nd:YAG laser irradiation time was almost two or three times longer than the bur treatment, respectively. From the SEM study, it was found that the lased cavity surface revealed various patterns of microirregularity, and there was also no smear layer. CONCLUSIONS: It can be suggested that under adequate water spray and with a careful irradiation technique, cavities without sign of thermal damage to the surrounding tissues as well as dental pulp could be produced with the Er:YAG and Nd:YAG laser.

Dental Caries↗