Biomedical subjects

Toshio Ohashi

Publications and source records attributed to Toshio Ohashi.

15 recordsLinked to original sources

PubMed2006

Predictive factors of acute urinary retention requiring catheterization following 125I prostate brachytherapy.

OBJECTIVE: To analyze predictive factors of acute urinary retention requiring catheterization after (125)I prostate brachytherapy. METHODS: A group of 227 consecutive patients with localized prostate cancer were treated with (125)I prostate brachytherapy between September 2003 and December 2004. The clinical, treatment-related and dosimetric factors were evaluated for the need for catheterization owing to urinary retention. RESULTS: Twelve patients (5.3%) required catheterization. The median time to onset was 2 days after implantation (range 1-7 days). Univariate analysis demonstrated that pre-implant ultrasound prostate volume, number of seeds, number of needles and neoadjuvant hormonal manipulation were predictive for catheterization. In multivariate analysis, the number of needles and neoadjuvant hormonal manipulation were significant independent predictive factors for catheterization (P = 0.002 and 0.025, respectively). The risk of catheterization in the cluster in which the number of needles was >24 was 4.07 times as high as that in the cluster in which the number of needles was < or =24 [11.3% versus 3.0%, P = 0.020; 95% confidence interval (CI) 1.24-13.36], and the risk in the hormonally manipulated patients was 7.05 times as high as that in the hormone-naïve patients (7.7% versus 1.2%, P = 0.034; 95% CI 0.89-55.64). CONCLUSION: Our data suggest that the number of needles and hormonal manipulation might be the strongest predictors for catheterization.

Aged↗

PubMed2006

Tamoxifen for recurrent desmoid tumor of the chest wall.

We report a case of a young woman with recurrent desmoid tumor. Computed tomography (CT) scans of the chest showed a large mass in the left chest wall. The tumor was unresectable because of the involvement of adjacent structures. Tamoxifen therapy led to marked tumor regression within 3 months. She had preserved her fertility, and thereafter she conceived a baby. In young women with recurrent desmoid tumor, tamoxifen should be considered as the first choice of treatment.

Adult↗

PubMed2006

Serial changes of international prostate symptom score following I-125 prostate brachytherapy.

BACKGROUND: This study was conducted to assess serial changes in the International Prostate Symptom Score (IPSS) within the first 12 months after iodine-125 (I-125) prostate brachytherapy. METHODS: Between September 2003 and June 2004, a group of 103 patients with localized prostate cancer was treated with I-125 prostate brachytherapy, either alone (monotherapy; 60 patients) or in combination with external-beam radiotherapy (combined therapy; 43 patients). The IPSS was obtained at preimplant, and at 1, 6, and 12 months after treatment. The minimum IPSS follow-up for this study was 12 months. Dosimetry was based on computed tomography (CT) scan 1 month postimplant. Clinical, treatment-related, and dosimetric factors were assessed for correlations with the maximum IPSS increase (the peak IPSS minus the preimplant IPSS). RESULTS: The median preimplant IPSS was 7.0, with a median peak of 16 at 1 month. The IPSS returned to baseline in 42 patients (40.8%) and it returned to within 3 points of the baseline in 64 (62.1%) at 1-year follow-up. On univariate and multivariate analyses, the maximum IPSS increase was best predicted by lower preimplant IPSS, in both the monotherapy and combined therapy groups. CONCLUSION: In our series, IPSS after prostate brachytherapy peaked at 1 month and gradually returned to approximately baseline at 12 months.

Aged↗

PubMed2006

[Influence of androgen deprivation therapy on prostate volume in patients with prostate cancer undergoing prostate brachytherapy with permanent seed implantation].

OBJECTIVE: Enlarged prostate often causes pubic arch interference during needle insertion on transperineal interstitial permanent prostate brachytherapy. Pre-treatment hormonal therapy is necessary for downsizing the prostate gland in such cases. The degree of prostate downsizing with anti-androgen treatment before iodine 125 permanent seed implant brachytherapy and its relation to clinical as well as pathological parameters were assessed. METHODS: From September 2003 to March 2005, 110 patients underwent permanent seed implantation and 86 patients of all received antiandrogen depriviation prior to the treatment at our institute. Prostate volume was measured using transrectal ultrasound at the time of cancer diagnosis and before the seed implant. Correlations between prostate downsizing and clinical as well as pathological parameters were evaluated. RESULTS: Mean percent volume of the prostate after the size reduction with average of 6.0 months antiandrogen monotherapy, 7.7 months LHRH agoniost and 8.2 months maximum androgen blockage (MAB) was 83%, 63%, and 60%, respectively. Mann-Whitney U test revealed that the degree of prostate downsizing is significantly correlated with the prostate volume in patients with prostate cancer utilizing LHRH agonists. CONCLUSIONS: Antiandrogen monotherapy can be an alternative for prostate downsizing before interstitial brachytherapy. Utilizing LHRH agonists or MAB is recommended for cases with larger gland volume.

Aged↗

PubMed2006

[Brachytherapy for prostate cancer].

This review article aims to overview modern prostate brachytherapy in Japan. Permanent transperineal prostate brachytherapy with I-125 started in September, 2003 in Japan. Brachytherapy has several advantages: the dose is adapted precisely to the tumor shape and size, and the long-lived isotope gives a higher tumor dose with less damage to normal tissue; less-time consuming for patients and staff: long-term results comparable to surgery or external beam series in the USA; and quality of life after brachytherapy also appealing. These advantages have brought about increasing use in Japan as well. Patients with a high probability of organ-confined disease and a low-risk group are appropriately treated with brachytherapy. Brachytherapy candidates with a significant risk of extraprostatic extension should be treated with supplemental external beam radiation therapy. High-dose-rate (HDR) brachytherapy with Ir-192 has preceded seed implants in Japan. HDR has some theoretical advantages. Long-term results of brachytherapy in the USA are comparable with surgery or external beam irradiation so far. We should develop more sophisticated brachytherapy techniques in Japan.

Brachytherapy↗

PubMed2005

Small lung tumors: long-scan-time CT for planning of hypofractionated stereotactic radiation therapy--initial findings.

PURPOSE: To prospectively use long-scan-time computed tomography (CT) to visualize the trajectory of tumor movements or the internal target volume. MATERIALS AND METHODS: The study was approved by the institutional review board. Written informed consent was obtained from participants after the study and the role of procedures were explained fully. During the planning of stereotactic radiation therapy for 10 patients (nine men, one woman; mean age, 77 years; range, 69-89 years) with small lung tumors (mean volume, 9.0 cm3; range, 3.6-24.9 cm3), fluoroscopic imaging, long-scan-time CT, and thin-section CT were performed. The tumor and the partial-volume-averaging effects that resulted from tumor movement were delineated on each section at long-scan-time CT performed during the patient's steady breathing with scan time of 8 seconds per image. Visualized internal target volume was defined by integrating the sections. A simple model was examined for estimating internal target volume on the basis of respiratory motion and gross target volume delineated on thin-section CT images. Visualized internal target volume and estimated internal target volume were compared quantitatively and graphically. The Mann-Whitney test was used to analyze the relation between gross target volume delineated on thin-section CT images and the ratio of visualized internal target volume to the defined gross target volume. RESULTS: The correlation coefficient between visualized internal target volume and estimated internal target volume was r = 0.98 (P < .001). The mean relative error +/- standard deviation was 1.9% +/- 19.0 (range, -11.0% to 56.4%). Excluding one case with an irregularly shaped tumor (56.4%), the mean relative error was -4.1% +/- 4.1. In patients with small tumors (defined gross target volume, < or = 10 cm3), the ratio of the visualized internal target volume to the defined gross tumor volume was significantly larger than that in patients with larger tumors (1.2-2.0 vs 1.0-1.2; P < .05). In some cases in which marginal spiculation depicted on thin-section CT images was blurred on long-scan-time CT images, the blurred area was erroneously excluded from the target volume. CONCLUSION: In most cases, values for visualized internal target volume and estimated internal target volume were similar and long-scan-time CT depicted virtually the entire tumor trajectory.

Aged↗

PubMed2005

Differences in pulmonary function before vs. 1 year after hypofractionated stereotactic radiotherapy for small peripheral lung tumors.

PURPOSE: To evaluate long-term pulmonary toxicity of stereotactic radiotherapy (SRT) by pulmonary function tests (PFTs) performed before and after SRT for small peripheral lung tumors. METHODS AND MATERIALS: A total of 17 lesions in 15 patients with small peripheral lung tumors, who underwent SRT between February 2000 and April 2003, were included in this study. Twelve patients had primary lung cancer, and 3 patients had metastatic lung cancer. Primary lung cancer was T1-2N0M0 in all cases. Smoking history was assessed by the Brinkman index (number of cigarettes smoked per day multiplied by number of years of smoking). Prescribed radiation doses at the 80% isodose line were 40-60 Gy in 5-8 fractions. PFTs were performed immediately before SRT and 1 year after SRT. Test parameters included total lung capacity (TLC), vital capacity (VC), forced expiratory volume in 1 s (FEV1.0), and diffusing capacity of lung for carbon monoxide (DLCO). PFT changes were evaluated in relation to patient- and treatment-related factors, including age, the Brinkman index, internal target volume, the percentages of lung volume irradiated with >15, 20, 25, and 30 Gy (V15, V20, V25, and V30, respectively), and mean lung dose. RESULTS: There were no significant changes in TLC, VC, or FEV1.0 before vs. after SRT. The mean percent change from baseline in DLCO was significantly increased by 128.2%. Univariate and multivariate analyses revealed a correlation between DLCO and the Brinkman index. CONCLUSIONS: One year after SRT as compared with before SRT, there were no declines in TLC, VC, and FEV1.0. DLCO improved in patients who had been heavy smokers before SRT, suggesting a correlation between DLCO and smoking cessation. SRT seems to be tolerable in view of long-term lung function.

Aged↗

PubMed2005

The value of drip infusion cholangiography using multidetector-row helical CT in patients with choledocholithiasis.

The purposes of this study were to investigate the feasibility of drip infusion cholangiography computed tomography (CTCh) for choledocholithiasis and to compare the detection of the stone on CTCh with that of MR cholangiopancreatography (MRCP). CTCh examinations were performed after infusion of intravenous biliary contrast material (iotroxic acid meglumine, 100 ml) for patients with suspected biliary diseases and were reconstructed to maximum intensity projection (MIP) and multiplanar reformation (MPR). Of 432 patients who underwent CTCh, we identified 15 who underwent surgery or cholangioscopic removal for choledocholithiasis and 32 patients who underwent cholecystectomy due to cholecystolithiasis. Their MRCP images were compared with the CTCh images. The sensitivity and specificity of CTCh for detecting choledochal stones were 87% and 96% whereas those of MRCP were 80% and 88%. The sensitivity and specificity of CTCh for detecting gallstones were 78% and 100% whereas those of MRCP were 94% and 88%. CTCh allowed high sensitivity and specificity for detecting choledochal stones but diminished the detection for cholecystolithiasis compared with MRCP.

Adult↗

PubMed2005

Acute urinary morbidity following I-125 prostate brachytherapy.

BACKGROUND: In Japan, iodine-125 (I-125) prostate brachytherapy has been legally approved since July 2003, and this method is becoming more popular. The purpose of the present study was to assess acute urinary morbidity within the first 6 months after I-125 prostate brachytherapy. METHODS: A group of 130 consecutive patients with localized prostate cancer was treated with I-125 prostate brachytherapy between September 2003 and June 2004,either alone (monotherapy; 66 patients) or in combination with external-beam radiotherapy (combined therapy; 64 patients). Urinary morbidity was evaluated using the National Cancer Institute - Common Terminology Criteria for Adverse Events, version 3.0. RESULTS: During the follow-up, 111 patients (85.4%) developed some degree of urinary symptoms such as frequency, retention, dysuria, incontinence, or hematuria. Urinary frequency (73.1%) and retention (66.9%) were the most common, and showed no significant differences between the monotherapy group and combined therapy group (P = 0.352 and P = 0.630, respectively). Six patients (4.6%) required catheterization for urinary obstruction; the median time to onset was 1.5 days (range, 1-192 days). Five of these 6 patients received monotherapy and the other received combined therapy. CONCLUSION: Manifestations of acute urinary morbidity, especially frequency and retention, are relatively common but acceptable events after I-125 prostate brachytherapy.

Aged↗

PubMed2005

[Pulmonary embolization of permanently implanted radioactive iodine-125 seeds for carcinoma of the prostate].

One year has passed since we started brachytherapy with radioactive iodine-125 seeds for carcinoma of the prostate. During the follow-up of patients, we have relatively frequently found migrated seeds in the lungs. Migrated seeds are reported to reach mainly the pulmonary artery and cause embolization without clinical symptoms. We counted the embolized seeds and determined the proportion of migrating seeds on chest X-ray exam. We found 47 cases of pulmonary embolization in our initial 100 cases. Less than half of the embolization were found in the chest X-ray exam performed on the next day after the implantation. We found more migrated seeds in the lower lung fields than in the upper and middle lung fields. Pulmonary embolization of implanted iodine-125 seeds is not unusual, and cases of prostate brachytherapy are likely to increase in Japan. We will have increased opportunities to observe chest X-ray films with migrated seeds in the future.

Aged↗

PubMed2005

[Seed loss through the urinary tract and retrieval after prostate seed implant].

This study describes our experience with seed loss and retrieval through the urinary tract following seed implants for prostate cancer, and offers Japanese guidelines for safety and management. Two hundred consecutive patients were analyzed. All patients were preplanned with a modified peripheral loading technique and implanted with a Mick applicator under ultrasound guidance. All patients were instructed to return excreted seeds, if any, to our center. Seed loss occurred in 6% of patients and 0.13% of seeds. Seed loss tended to occur in the early period through either urine or ejaculation.

Brachytherapy↗

PubMed2005

[Experience of brachytherapy using I-125 seed permanent implants for localized prostate cancer].

PURPOSE: We report here our experience of brachytherapy using I-125 seeds for localized prostate cancer in 100 patients. MATERIALS AND METHODS: We carried out brachytherapy with I-125 seed permanent implants in 100 patients with localized prostate cancer between September 2003 and October 2004. Preplanning dosimetry was done using transrectal ultrasonic images obtained three or four weeks prior to treatment. Using transrectal ultrasound, we inserted I-125 seeds in the prostate through needles according to the preplanning diagram. We then examined the results on prostate CT performed one month later. RESULTS: It was necessary to describe transrectal ultrasonic image such as preplanning. There were several cases in which the source arrangement of the schedule was corrected immediately before the operation. In the examination after one month, the numerical value at the start of treatment initially was not satisfactory, but we eventually obtained a result that could to be evaluated. CONCLUSION: We carried out permanent implant brachytherapy for localized prostate cancer using I-125 seeds and reported our experience.

Aged↗

PubMed2004

Radiation injury after hypofractionated stereotactic radiotherapy for peripheral small lung tumors: serial changes on CT.

OBJECTIVE: We studied the serial changes and CT manifestations of pulmonary radiation injury after hypofractionated stereotactic radiation therapy for peripheral small lung tumors. SUBJECTS AND METHODS. Hypofractionated stereotactic radiation therapy was applied to 20 patients with proven primary (n = 11) or metastatic (n = 9) lung cancer, for a total of 22 lesions of 3 cm or less in diameter located within 3 cm from the parietal pleural surface. Follow-up CT was scheduled at 1 and 3 months, and every 3 months thereafter. RESULTS: Ground-glass opacities were observed around four (18%) of 22 lesions at 3-6 months. The opacities nearly corresponded to the planned target volume, but half of them were unevenly distributed. Ground-glass opacities gradually disappeared or evolved into dense consolidation while shrinking. Dense consolidations developed in 16 (73%) of 22 lesions, including seven in the center of the planned target volume and nine in the periphery of the planned target volume. Dense consolidations moved in six of these 16 lesions and gradually shrank, becoming fixed as solid or linear opacities approximately 12 months later. CONCLUSION: The pulmonary opacities observed after hypofractionated stereotactic radiation therapy for peripheral small lung tumors may not precisely correspond to the planned target volume (unlike those with conventional radiation therapy) and may change in shape and location dynamically during the first year. Knowledge of these findings is necessary to avoid misunderstandings concerning tumor regrowth or new tumors.

Aged↗

PubMed2001

Fermentable-sugar-level-dependent regulation of leukotoxin synthesis in a variably toxic strain of Actinobacillus actinomycetemcomitans.

Actinobacillus actinomycetemcomitans, a Gram-negative periodontopathic bacterium, produces a leukotoxin belonging to the RTX family. The production of leukotoxin varies greatly among different strains of this species and under different culture conditions. A toxin-production-variable strain, 301-b, stably produces significant amounts of leukotoxin in anaerobic fructose-limited chemostat cultures, but does not do so in the presence of excess fructose. This communication describes the cloning and sequencing of the leukotoxin promoter region from 301-b, showing that this strain has a promoter region similar to that from strain 652, a moderately toxic strain. Northern blot analysis using a leukotoxin gene probe demonstrated that change in toxin production in response to the level of external fructose was due to alteration in the transcriptional level of the leukotoxin gene. Pulsing of fructose into the fructose-limited chemostat culture remarkably reduced the intracellular cAMP level from 40 pmol (mg dry wt cells)(-1) to 3.1 pmol (mg dry wt cells)(-1), which was restored when the culture was returned to fructose-limited conditions. Further, it was found that addition of external cAMP to the culture with excess fructose resulted in an apparent recovery of leukotoxin production. Taken together, these findings indicate that a cAMP-dependent mechanism, possibly a catabolite-repression-like system, may be involved in the regulation of leukotoxin production in this bacterium.

Aggregatibacter actinomycetemcomitans↗

PubMedDate not supplied

Successful pregnancy and normal delivery after whole craniospinal irradiation in two patients.

BACKGROUND: Two cases of normal pregnancies and deliveries after whole craniospinal irradiation (WCSI) are described, and whether the ovaries can be left out of the WCSI field by identifying ovarian position using magnetic resonance imaging (MRI) is determined. MATERIALS AND METHODS: The distance between the upper edge of the pubic symphysis and the central part of the ovary was measured on MRI in 17 women. RESULTS: The right ovary was located 20.3-68.4 mm to the right of and 33.7-113.5 mm above the upper edge of the pubic symphysis; the left ovary was located 26.2-72.5 mm to the left and 25.8-106.6 mm above this edge. The lower border of the spinal field in WCSI should be the caudal border of the thecal sac, i.e., S2-S4. The line of this location, which nearly approximates normal ovarian position, should be employed in radiotherapy planning to avoid irradiating at least one ovary with its thecal sac. Omitting this area from the WCSI field in women of childbearing age with a good long-term prognosis, preserves potential fertility. CONCLUSION: It appears that the ovaries might be excluded from the WCSI field, using appropriate techniques, so as to preserve female fertility.

Adolescent↗