Biomedical subjects

N Miyanaga

Publications and source records attributed to N Miyanaga.

At least 19 recordsLinked to original sources

PubMed2004

Electron bunch trapping and compression by an intense focused pulse laser.

A focused short-pulse laser of TEM (1,0)+TEM (0,1) mode has two intensity peaks in the radial direction, so that the transverse ponderomotive force may trap electrons between the two peaks. At the same time the longitudinal ponderomotive force may accelerate electrons at the head of the laser pulse, when the laser is focused. When the electrons move to the laser tail, the laser may diverge and the electron deceleration becomes relatively weak. Our numerical analyses demonstrate that electrons are trapped well by the laser potential well, and that at the same time the acceleration by the longitudinal ponderomotive force induces the electron bunch compression. This trapping and compression mechanism is unique: the electron bunch can be compressed to the scale of the laser pulse length.

Journal Article↗

PubMed2002

Spectroscopic determination of dynamic plasma gradients in implosion cores.

The time-dependent gradient structure of a laser-compressed, high-energy-density plasma has been determined using a method based on the simultaneous analysis of time-resolved x-ray monochromatic images and x-ray line spectra from Ar-doped D2 implosion cores. The analysis self-consistently determines the temperature and density gradients that yield the best fits to the spatial-emissivity profiles and spectral line shapes. This measurement is important for understanding the spectra formation and plasma dynamics associated with the implosion process. In addition, since the results are independent of hydrodynamic simulations, they are also important for comparison with fluid-dynamic models.

Journal Article↗

PubMed2001

Fast heating of ultrahigh-density plasma as a step towards laser fusion ignition.

Modern high-power lasers can generate extreme states of matter that are relevant to astrophysics, equation-of-state studies and fusion energy research. Laser-driven implosions of spherical polymer shells have, for example, achieved an increase in density of 1,000 times relative to the solid state. These densities are large enough to enable controlled fusion, but to achieve energy gain a small volume of compressed fuel (known as the 'spark') must be heated to temperatures of about 108 K (corresponding to thermal energies in excess of 10 keV). In the conventional approach to controlled fusion, the spark is both produced and heated by accurately timed shock waves, but this process requires both precise implosion symmetry and a very large drive energy. In principle, these requirements can be significantly relaxed by performing the compression and fast heating separately; however, this 'fast ignitor' approach also suffers drawbacks, such as propagation losses and deflection of the ultra-intense laser pulse by the plasma surrounding the compressed fuel. Here we employ a new compression geometry that eliminates these problems; we combine production of compressed matter in a laser-driven implosion with picosecond-fast heating by a laser pulse timed to coincide with the peak compression. Our approach therefore permits efficient compression and heating to be carried out simultaneously, providing a route to efficient fusion energy production.

Journal Article↗

PubMed2001

[Verify the optimum administration of anticancer agent--cisplatin].

Cisplatin shows effectiveness for various solid cancers and often plays a role as the key drug in combination chemotherapy. The most common method of cisplatin administration is bolus intra-venous injection. However, other administration methods are tried in order to reinforce the effect, and also to reduce the side effects. Generally, renal damage is more prominent with bolus injection. In contrast, bone marrow suppression is more severe with intermittent administration. Although there is no clear evidence about the anti-tumor effects, a dramatic local effect is sometimes observed by intra-arterial chemotherapy. By intraperitoneal chemotherapy, while a systemic effect is observed in addition to local effects, due consideration of the systemic side effects is also needed. These protocols are used in many institutes, but the efficacy is not yet proven by comparison trials. In future, randomized prospective studies should be performed to test the usefulness of the regimens.

Antineoplastic Agents↗

PubMed2001

[Bladder cancer].

Explore the source record for details and available documents.

Age Factors↗

PubMed2000

A bladder preservation regimen using intra-arterial chemotherapy and radiotherapy for invasive bladder cancer: a prospective study.

BACKGROUND: A prospective study was performed to investigate combined treatment with intra-arterial chemotherapy and radiation therapy for bladder preservation in locally invasive bladder cancer. METHODS: Patients with invasive bladder cancer, stage T2-3N0M0, were included in the study. Intra-arterial chemotherapy was performed with three injections of methotrexate and cisplatin at 3-week intervals. Simultaneously, the patients underwent X-ray irradiation (40 Gy) of the small pelvic space. Where a post-treatment transurethral resection (TUR) biopsy showed no residual tumor, the tumor site was irradiated by a 30 Gy proton beam and the bladder was preserved. Where tumors remained, radical cystectomy was performed. RESULTS: Between 1990 and 1996, 42 patients were treated according to this protocol. Post-treatment TUR biopsy and urine cytology showed no residual tumors in 39 of 42 cases (93%). The bladder was preserved in accordance with the study protocol in 36 cases. A median follow-up of 38 months showed 3-year non-recurrence in 72% of bladder-preserved patients and the rate of bladder preservation was 84%. The nine recurrences included eight cases of superficial bladder recurrence. One cancer death occurred among the bladder-preservation patients, giving 3-year survival and cause-specific survival rates of 84% and 100%, respectively. Although bladder function decreased slightly in compliance, bladder capacity was retained in almost all cases. CONCLUSIONS: This regimen is useful for bladder preservation in T2-3 locally invasive bladder cancer. Information from more cases and the results of more long-term observations are needed, as is an evaluation of appropriate subject selection and factors associated with quality of life issues, particularly regarding bladder function.

Aged↗

PubMed2000

High-dose chemotherapy with peripheral blood stem cell transplantation for advanced testicular cancer.

BACKGROUND: The present study was performed in order to investigate the efficacy and safety of high-dose chemotherapy for the treatment of patients with advanced testicular cancer. METHODS: Seven patients were treated with high-dose carboplatin, etoposide and cyclophosphamide followed by peripheral blood stem cell transplantation. Five patients received one cycle and two patients received two cycles of the high-dose chemotherapy. RESULTS: Of the seven patients, one achieved a complete response and four achieved partial responses with markers negative. As a result of subsequent surgery for residual tumors, three of the four partial responders showed no residual cancer cells. One patient who did not undergo surgery received radiotherapy after the high-dose chemotherapy and the residual tumors disappeared. All five patients who had either a complete or partial response are still alive and without evidence of disease at 12, 27, 30, 37 and 40 months. One patient is alive with disease at 7 months and one died of progressive disease at 6 months. The hematologic recovery after high-dose chemotherapy was rapid and non-hematologic toxicities were usually mild and manageable. CONCLUSIONS: High-dose chemotherapy followed by peripheral blood stem cell transplantation is safe and effective for use in patients with far-advanced testicular cancer, particularly when the high-dose chemotherapy is conducted as the initial treatment. Further larger and long-term follow-up studies are needed to define the role of high-dose chemotherapy on testicular cancer.

Adult↗

PubMed2000

[Intrascrotal tumors: a clinicopathologic study of 15 cases].

PURPOSE: We reviewed cases of intrascrotal tumors treated at our institution except for germ cell testicular tumors. PATIENTS AND METHODS: From 1977 to 1998 (22 years), 120 cases of intrascrotal tumors treated at the University of Tsukuba. Of these, 15 cases (12.5%) were not germ cell testicular tumors. The patients' ages varied between 2 and 77 years with a mean of 49.6. RESULTS: The most common complaint regarding symptoms was painless testicular enlargement. Tumor weight ranged from 2 to 200 g, with an average of 104.6 g. The histological diagnoses of 15 patients were 8 malignant lymphomas, 2 paratesticular rhabdomyosarcomas, 2 metastatic tumors (origin; stomach and prostate), 1 epidermoid cyst, 1 cyst of tunica testis, and 1 adenomatoid tumor. As for the cases with malignant lymphoma, all of them were non-Hodgkin's lymphoma whose clinical stages were stage I in 2 cases and stage IV in 6 cases. Five 8 patients died in spite of systemic chemotherapy after an orchiectomy, whereas 2 cases with metastatic tumors died of primary cancer, and two cases with paratesticular rhabdomyosarcoma are still alive and have had no evidence of disease. CONCLUSIONS: Intrascrotal tumors except for germ cell testicular tumors are not common, and consist of various diseases. In particular, some kinds of malignant lymphoma mimic anaplastic seminoma histopathologically. Therefore, accurate diagnosis and precise treatment is important in the patient with intrascrotal tumors.

Adolescent↗

PubMed2000

[Evidence-based medicine for urological cancer chemotherapy].

We reviewed the treatment results of urological cancer chemotherapy from the standpoint of evidence based medicine. In the treatment of advanced transitional cell carcinoma of the urothelium, M-VAC (MTX + VBL + ADM + CDDP) is regarded as the standard regimen; however, durable event-free survival is rare. There is no level 1 evidence to date showing that the use of neoadjuvant or adjuvant cisplatin-based regimens will improve survival in cases of locally advanced bladder cancer. Immunotherapy with interferon or interleukin-2 produces a small survival advantage in patients with metastatic renal cell carcinoma. There is no evidence that adjuvant interferon-alpha administration will improve the survival in those with non-metastatic renal cell carcinoma. Systematized cisplatin-based treatment protocols have been established in patients with advanced testicular germ cell tumor by means of many randomized controlled trials. Several clinical trials are under way to prove the efficacy of high dose chemotherapy (with autologous stem-cell support) in patients with poor risk germ cell tumors. We do not yet have sufficient data to conclude whether maximal androgen blockade will prolong the survival in patients with metastatic prostate cancer, nor to conclude whether neoadjuvant androgen depletion treatment improve disease free survival of the patients after radical prostatectomy.

Carcinoma, Transitional Cell↗

PubMed1999

Urinary nuclear matrix protein 22 as a new marker for the screening of urothelial cancer in patients with microscopic hematuria.

PURPOSE: The aim of the present study was to determine the clinical usefulness of nuclear matrix protein 22 (NMP22) as a new urinary marker for the screening of urothelial cancer in patients with microscopic hematuria, especially in comparison with that of voided urine cytology. METHODS: Patients with microscopic hematuria detected at a health examination, who were advised by a consulted urologist to have a cystoscopical examination, were asked to enter this study. Urine samples were collected before cystoscopy and divided into two portions for NMP22 test and voided urine cytology. RESULTS: Of the 309 patients with microscopic hematuria, 22 cases (7.1%) of urothelial cancer and one case of prostate cancer were detected. For the other cases, 128 (41.4%) were of benign diseases and 158 (51.1%) were designated as having no evidence of disease (NED). The median NMP22 values for urothelial cancer, other diseases and NED were 35.5, 6.7 and 6.0 U/mL, respectively, with 95% confidence intervals of 19.9-228.2, 5.1-9.3 and 5.4-7.2, respectively. The sensitivity of the NMP22 test for urothelial cancer was 90.9% (20/22), whereas the sensitivity of voided urine cytology was only 54.5% (12/22). CONCLUSIONS: The present study indicates that urinary NMP22 is a useful tool for the screening of urothelial cancer in patients with microscopic hematuria.

Adult↗

PubMed1999

Lower urinary tract function after intra-arterial chemotherapy with concurrent pelvic radiotherapy for invasive bladder cancer.

BACKGROUND: Intra-arterial chemotherapy with concurrent pelvic radiotherapy as a bladder-sparing regimen for invasive bladder cancer is highly promising for selected patients. However, lower urinary tract function after this treatment has not been fully investigated. METHODS: The urodynamic effects of intra-arterial chemotherapy with concurrent pelvic radiotherapy were retrospectively evaluated in 14 patients with organ-confined invasive bladder cancer. The post-treatment urodynamic findings were compared with the pretreatment ones (n = 7), and a comparison was made between the serial urodynamic findings after the treatment in another seven patients who were able to undergo the pretreatment urodynamic study (UDS). RESULTS: The median follow-up period up to the latest UDS was 34 months. Of the 14 patients, the latest UDS revealed some storage dysfunctions in 11 (79%) and some emptying dysfunctions in three (23%). Uninhibited detrusor contraction and decreased bladder compliance were recorded in 29 and 43% at the pretreatment UDS and approximately 50-60 and 20-60% in the serial follow-up studies, respectively (n = 7). Impaired detrusor contractility lasted in one patient. In the seven patients without the pretreatment UDS, decreased maximum cystometric capacity and decreased compliance were recorded in approximately 50-60 and 20-60% at the serial UDS, respectively. Detrusor contractility was aggravated in one patient and completely lost in one with time. CONCLUSIONS: The urodynamic findings indicate that the bladder-sparing regimen might result in perpetuating the lower urinary tract dysfunctions due to invasive bladder cancer itself and/or transurethral surgery and might injure the infrasacral autonomic nerves and the bladder itself.

Aged↗

PubMed1999

[Assessment of QOL and survival for patients undergoing radical cystectomy or bladder preservation for invasive bladder cancer].

PURPOSE: In this study, we have retrospectively compared patient backgrounds, prognosis and QOL (quality of life) in patients with invasive bladder cancer treated by radical cystectomy or by bladder preservation. PATIENTS AND METHODS: This study enrolled recent 30 cases from each institutions, totally 120 cases from four institutions. All patients were diagnosed with invasive bladder cancer in stage T 2 or T 3, N 0, M 0. The patients planned for preserving the bladder were treated with a combination of intra-arterial chemotherapy and radiation as an induction therapy. The questionnaire used to assess QOL was the EORTC QLQ-C 30 (Japanese-language edition). RESULTS: Radical cystectomy was selected as the initial treatment in 60 cases (the planned radical cystectomy group). Bladder preservation was planned but the presence of residual tumors after induction therapy underwent radical cystectomy in 18 cases (the preservation-radical cystectomy group). Bladder preservation was achieved in 42 cases (the preservation group). In a comparison of background factors, histologically grade 3 tumor and cases with histology other than transitional cell carcinoma, were significantly common in the planned radical cystectomy group. Because this study is not an randomized test, it is difficult to compare the outcomes between the patients treated by radical cystectomy or by bladder preservation. However, it is indicated that the candidates for bladder preservation therapy exist among the patients with T 2 or T 3, N 0, M 0 bladder cancer. Quality of life, as evaluated from global QL and from physical, cognitive, and emotional function, tended to be better in the patients with their bladder, although no difference was noted among the groups with regard to life role or social function. Symptoms such as sleep disturbance and diarrhea were common in the radical cystectomy groups, and financial impact, constipation, appetite loss, and dyspnea also tended to more frequently affect patients in these groups. CONCLUSION: Our results indicate that bladder preservation treatment using an induction therapy is one of option of the treatment for clinically T 2 or T 3, N 0, M 0 bladder cancer. We need a prospective randomized study with a long-term follow-up to elucidate true candidates for this treatment.

Aged↗

PubMed1999

Transurethral resection of benign prostatic hyperplasia using a vaporizing resecting loop, UROloop.

New electrosurgical instruments for the treatment of benign prostatic hyperplasia (BPH) have been developed during the past few years. We determined the efficacy and safety of transurethral prostatectomy (TUR-P) using a new electrosurgical device (UROloop) for the treatment of BPH. Twenty-four patients, with a mean age of 67.7 years, with BPH underwent TUR-P using the UROloop between April 1996 and March 1997. We evaluated the pre- and postoperative symptom scores and urodynamic parameters of the patients. The International Prostate Symptom Score (IPSS) was used for symptom scoring. The urodynamic parameters included peakflow rates (PFR) and postvoid residual urine (PVR). The average preoperative IPSS score for all patients was 15.4 +/- 1.4. The IPSS score was significantly improved to 4.3 +/- 0.24 at 12 weeks after the TUR-P (p = 0.0002). The average PFR was increased by 117% at 12 weeks postoperatively. The average preoperative PVR of 65.4 ml was reduced to 15.2 ml postoperatively. The changes in the urodynamic parameters were statistically significant. No severe complications were observed in the present study. The changes in the serum sodium and hemoglobin levels were small. This study revealed significantly sustained clinical improvement with minimal morbidity. The results of the present study also confirmed the usefulness of the new endoscopic treatment for BPH.

Aged↗

PubMed1999

[Development of Japanese version of QOL questionnaire for bladder and prostate cancer patients using FACT-Bl and P: pilot study].

BACKGROUND: Quality of life (QOL) has been known to be a prognostic factor as well as the endpoint of treatment efficacy in many clinical fields. We have begun a US-Japan collaborative project introducing a QOL questionnaire, the FACT (Functional Assessment of Cancer Therapy), into Japan. We report on the translation process, results of the pilot study, and future plans for translating the Japanese version of the FACT subscales, FACT-Bl (for bladder cancer) and FACT-P (for prostate cancer). METHODS: The FACT translation procedure, which is quite rigorous, follows a four-step methodology. After completing the translations, we tested the translated FACT-G (general questionnaire) and subscales for bladder and prostate cancer patients. The questionnaires were tested on 30 outpatients at Tsukuba University Hospital (15 bladder, 15 prostate). The only eligibility requirement to participate in the study was a confirmed diagnosis of cancer of the bladder or prostate. RESULTS AND DISCUSSION: There was satisfactorily high internal consistency of FACT-G of both bladder and prostate cancer patients. FACT-Bl study included patients having undergone radical cystectomy as well as those who had not. Because not all items were answered by all patients, the Cronbach's alpha coefficient for the FACT-Bl subscale could not be computed. Further evaluation of the FACT-Bl concerning the surgical procedures affecting QOL is needed. We are currently planning to make the further refinement of the questionnaire in order to make it more suitable for bladder cancer patients. FACT-P subscale had an alpha coefficient of 0.82 and was determined to be useful in its present form.

Aged↗

PubMed1999

[A case of synchronous multifocal urothelial tumors in a patient with phenacetin abuse].

A 79-year-old male with phenacetin abuse was admitted to our University Hospital for treatment of asymptomatic gross hematuria. Intravenous urograpdy and computed tomography revealed synchronous right renal pelvic carcinoma and bladder carcinoma. Right nephroureterectomy and transurethral resection of bladder tumor (TUR-Bt) were performed. Histologically, right renal pelvic tumor and bladder tumor were both transitional cell carcinomas of grade 2, pT1, and grade 1 = 2, Ta, respectively. Additionally, pathological examination revealed two distal ureteral tumors, which were transitional cell carcinomas of grade 2, pTa. He also had a history of heavy tobacco-smoking (20 cigarettes per day for 50 years). We discuss the relationship between transitional cell carcinoma and phenacetin abuse as well as the influence of tobacco-smoking, and review the literature.

Aged↗

PubMed1999

[Cases of refractory testicular cancer treated with all trans-retinoic acid].

We reported two cases of chemotherapy-refractory testicular cancer treated with all trans-retinoic acid (ATRA). Case 1. A 21-year-old male patient underwent salvage surgery for lung metastasis which had developed after treatment with three different cisplatin-based chemotherapy regimens for malignant teratoma. After recovery from surgery, he was treated with oral ATRA at daily dose 80 mg/m2 for four weeks. Case 2. A-45-year-old patient suffered from lung metastasis after orchiectomy for teratocarcinoma. The patient failed to achieve a complete response despite two different cisplatin-based chemotherapy and high dose chemotherapy regimens with bone marrow rescue. He was treated with oral ATRA for five weeks. Both patients showed disease progression with increase in tumor size and elevation of tumor marker during ATRA therapy. Side effects were acceptable except the headache in Case 2, who needed a dose reduction of ATRA. In conclusion, oral ATRA with this dose failed to show clinical antitumor activity in patients with refractory testicular cancer.

Adult↗

PubMed1998

Neutropenic colitis as a complication of high-dose chemotherapy for refractory testicular cancer.

A 44-year-old man received high-dose chemotherapy with carboplatin, etoposide and cyclophosphamide followed by autologous peripheral-blood stem-cell transplantation for treatment of refractory nonseminomatous testicular cancer (seminoma plus choriocarcinoma). The patient developed fever, watery diarrhea and abdominal pain at 10 days after the initiation of high-dose chemotherapy. Radiological examinations revealed adynamic ileus with thickened colon and small bowel wall and increasing ascites over the next 3 days. The patient subsequently suffered from disseminated intravascular coagulation, renal failure and hyperbilirubinemia despite systemic antibiotic therapy. Intensive medical care could barely avoid the fatal outcome. Neutropenic colitis has been recognized as a complication of acute leukemia or aplastic anemia. The present case indicates that this serious gastrointestinal complication can occur under profound neutropenic conditions induced by intensive chemotherapy for solid cancer.

Adult↗

PubMed1998

[Effect of UFT on treatment of urological cancer--effect of UFT on treatment of invasive bladder cancer and advanced prostate cancer. Ibaraki Urological Cancer Chemotherapy Study Group].

A prospective randomized joint study was conducted to evaluate the usefulness of UFT 1) as a postoperative adjuvant therapy in patients with invasive bladder cancer who had undergone curative combination therapy with operation and/or chemotherapy and/or radiation therapy, 2) as an endocrine chemotherapy in patients with newly diagnosed stage C/D prostate cancer, for a period of 3 years from January, 1992. For bladder cancer, of 36 patients with invasive bladder cancer, clinically cured by combination therapy, 20 patients were treated with UFT as an adjuvant chemotherapy over 12 months, and they were compared to 16 patients with no adjuvant therapy. After excluding 10 inappropriate patients, 12 patients in the UFT treatment group and 14 patients with no adjuvant treatment group were observed. For prostate cancer, of 29 patients with clinically stage C/D prostate cancer, 13 were treated with endocrine therapy in combination with UFT, and 16 patients were treated with endocrine therapy alone. After excluding 7 inappropriate patients, 10 patients with endocrine chemotherapy and 12 patients with hormonal therapy were observed. The non-recurrence rate, survival rate and side effects of UFT were evaluated. In the study of bladder cancer, neither a significant difference of non-recurrent rate nor of survival rate was seen between the two groups. In the study of prostate cancer, neither a significant difference of non-recurrent rate nor of survival rate was seen between the two groups. These findings suggest UFT is less useful as an adjuvant therapy for the invasive bladder cancer and as an endocrine chemotherapy for newly diagnosed advanced prostate cancer.

Administration, Oral↗