Search PubMed⌕ Search

Biomedical subjects

M Miyakawa

Publications and source records attributed to M Miyakawa.

At least 19 recordsLinked to original sources

Akt activation and localisation correlate with tumour invasion and oncogene expression in thyroid cancer.

INTRODUCTION: Akt activation is involved in the pathogenesis of inherited thyroid cancer in Cowden's syndrome and in sporadic thyroid cancers. In cell culture, Akt regulates thyroid cell growth and survival; but recent data suggest that Akt also regulates cell motility in non-thyroid cell lines. We therefore sought to evaluate the role of Akt in thyroid cancer progression. METHODS: We evaluated 46 thyroid cancer, 20 thyroid follicular adenoma, and adjacent normal tissues samples by immunohistochemistry for activated Akt (pAkt), Akt 1, 2, and 3, and p27 expression. Immunoblots were performed in 14 samples. RESULTS: Akt activation was identified in 10/10 follicular cancers, 26/26 papillary cancers, and 2/10 follicular variant of papillary cancers, but in only 4/66 normal tissue samples and 2/10 typical benign follicular adenomas. Immunoactive pAkt was greatest in regions of capsular invasion; and was localised to the nucleus in follicular cancers and the cytoplasm in papillary cancers, except for invasive regions of papillary cancers where it localised to both compartments. Immunoactive Akt 1, but not Akt 2 or Akt 3, correlated with pAkt localisation, and nuclear pAkt was associated with cytoplasmic expression of p27. In vitro studies using human thyroid cancer cells demonstrated that nuclear translocation of Akt 1 and pAkt were associated with cytoplasmic p27 and cell invasion and migration. Cell migration and the localisation of Akt 1, pAkt, and p27 were inhibited by PI3 kinase, but not MEK inhibition. DISCUSSION: These data suggest an important role for nuclear activation of Akt 1 in thyroid cancer progression.

Adenoma↗

Experimental validation of a linear model for data reduction in chirp-pulse microwave CT.

Chirp-pulse microwave computerized tomography (CP-MCT) is an imaging modality developed at the Department of Biocybernetics, University of Niigata (Niigata, Japan), which intends to reduce the microwave-tomography problem to an X-ray-like situation. We have recently shown that data acquisition in CP-MCT can be described in terms of a linear model derived from scattering theory. In this paper, we validate this model by showing that the theoretically computed response function is in good agreement with the one obtained from a regularized multiple deconvolution of three data sets measured with the prototype of CP-MCT. Furthermore, the reliability of the model as far as image restoration in concerned, is tested in the case of space-invariant conditions by considering the reconstruction of simple on-axis cylindrical phantoms.

Computer Simulation↗

Re-evaluation of the latent period of bladder cancer in dyestuff-plant workers in Japan.

BACKGROUND: The carcinogenesis of benzidine (BZ) and beta-naphthylamine (BNA) for bladder is well known. Although it was thought to be rare to develop occupational bladder cancer more than 20 years after the exposure to these chemicals, there are still new clinical cases even 30 years after exposure. The purpose of this study was to re-evaluate the latent carcinogenic period of BZ and BNA, in order to set the safety period after exposure for the health surveillance system. METHODS: The subjects were 236 dyestuff-plant workers in Tokyo, who had been exposed to these dyestuffs. The incidence of bladder cancer and its histopathology in this group was surveyed in the period from 1962 to 1996. RESULTS: Nineteen workers (8.1%) were found to have bladder cancers. The exposure period for these 19 patients was 82.0 +/- 50.2 months. The mean +/- SD latent period from the subjects' initial and final exposure until tumor development was 29.5 +/- 8.2 years and 20.1 +/- 10.6 years, respectively. Significantly, a negative correlation (Pearson) was observed between the exposure period and the latent period from the end of exposure to cancer onset (R = -0.544, P < 0.05). All tumors except one were transitional cell carcinoma. Flow cytometric analysis was performed in 11 patients and all of these patients had DNA aneuploidy. CONCLUSIONS: The latent periods of bladder cancer caused by BZ and BNA were longer than previously expected. It is necessary to survey the onset of bladder cancer in exposed workers more than 30 years after the initial exposure.

2-Naphthylamine↗

Severe thyrotoxicosis induced by thyroid metastasis of lung adenocarcinoma: a case report and review of the literature.

A 50-year-old woman who had undergone lung lobectomy because of lung adenocarcinoma presented with thyrotoxicosis, neck swelling, and cervical lymphadenopathy one month after the operation. The total serum triiodothyronine (T3) and thyroxine (T4) levels were markedly elevated to 514 ng/dL and 26.4 microg/dL, respectively, and serum thyrotropin (TSH) was suppressed to less than 0.005 microU/mL. Although the thyroid gland had been normal before surgery, chest computed tomography (CT) scan revealed a markedly enlarged thyroid gland only 1 month after surgery. 123I uptake for 24 hours was suppressed to 4% in the thyroid gland with no uptake elsewhere including the lung. Fine-needle aspiration cytology (FNAC) of the thyroid showed invasion of poorly differentiated adenocarcinoma cells, cytologically identical to the cells obtained from sputum and those infiltrating the resected sections of the lung adenocarcinoma. Immunohistochemical studies of resected lung tissues did not show positive staining for thyroglobulin, carcinoembryonic antigen (CEA), or surfactant protein A. Clinically, the thyrotoxicosis had spontaneously improved, followed by a hypothyroid state with shrinkage of the thyroid gland after chemotherapy. Despite repeated chemotherapy and the administration of thyroxine for hypothyroidism, the patient died of respiratory failure 9 months after the onset of thyrotoxicosis. From these findings and the clinical course, thyroid metastasis, developing subacutely from lung adenocarcinoma, was diagnosed. We speculate that aggressive invasion of tumor cells into the thyroid gland resulted in highly destructive thyrotoxicosis.

Adenocarcinoma↗

Seasonal variation in heart rate variability in asthmatic children.

Asthma is a "seasonal disease" with symptoms either aggravated by environmental changes during specific seasons or prevalent at certain times of the year for other reasons. We examined whether the heart rate variability (HRV) of asthmatic children changes by season. The HRV during a portion of one night (00:00-04:00) and day (12:00-16:00) and the entire 24h period (00:00-24:00) during each of the four seasons was analyzed. The data of 95 children with asthma and 106 healthy children, as controls, were assessed. In children with asthma during the 24h period, seasonal variation in the low-frequency (LF) band (0.04-0.15 Hz) and the high-frequency (HF) band (0.15-0.4 Hz) were detected (HF: F=6.81, p=.0003; LF: F=4.18, p= .008). The HF value in the summer was significantly higher than in autumn and spring (Scheffe test: autumn vs. summer, s = 4.46, p < .001: spring vs. summer, s = 2.86, p < .05), while the LF value in autumn was significantly lower than in summer (s = 3.42, p < .01). In the control group, no seasonal variation in HF, LF, or LF/HF was detected. The findings infer the HRV, a surrogate measure of autonomic nervous system function, of asthmatic children is more susceptible to seasonal changes brought about by either endogenous annual rhythms or environmental weather phenomena.

Adolescent↗

Image restoration in chirp-pulse microwave CT (CP-MCT).

Chirp-pulse microwave computed tomography (CP-MCT) is a technique for imaging the distribution of temperature variations inside biological tissues. Even if resolution and contrast are adequate to this purpose, a further improvement of image quality is desirable. In this paper, we discuss the blur of CP-MCT images and we propose a method for estimating the corresponding point spread function (PSF). To this purpose we use both a measured and a computed projection of a cylindrical phantom. We find a good agreement between the two cases. Finally the estimated PSF is used for deconvolving data corresponding to various kinds of cylindrical phantoms. We use an iterative nonlinear deconvolution method which assures nonnegative solutions and we demonstrate the improvement of image quality which can be obtained in such a way.

Algorithms↗

Volume-weighted mean nuclear volume. Is this new prognosticator comparable in different institutions?

OBJECTIVE: To determine whether volume-weighted mean nuclear volume (MNV) obtained at one institution is comparable to that from other institutions. STUDY DESIGN: MNV calculated from histologic slides obtained at three hospitals--Shizuoka Prefectural Hospital (SPH), Shimada Municipal Hospital (SMH) and Shizuoka City Hospital (SCH)--were compared. Between December 1994 and June 1996, transurethral resection of bladder tumor or transurethral resection of the prostate was performed on 37 patients at SPH and 50 patients at SMH; histologic specimens from 40 cases of bladder tumors, 63 cases of normal bladder mucosa, 28 cases of benign prostatic hyperplasia and 1 case of prostate cancer were obtained. A portion of each specimen obtained at SPH or SMH was carried to SCH, and histologic slides were made at SCH using it. Using the remaining position of each specimen, histologic slides were then prepared at each hospital. Estimates of MNV were made from all histologic slides from each hospital, and the differences in MNV between the hospitals were analyzed. In addition, intraobserver and interobserver reproducibility were analyzed using 50 specimens obtained between December 1994 and August 1995. RESULTS: On linear regression analysis, comparison of MNVs calculated from the histologic slides from SPH and SCH and those calculated from SMH and SCH revealed high correlation coefficients (R = .966 and .966, respectively), and the slope of the regression line did not differ significantly from unity. The paired t test also disclosed no significant difference between MNVs calculated at the two hospitals. Furthermore, the correlation coefficients for intraobserver and interobserver reproducibility of MNV estimates were also high (R = .918 and .949, respectively). CONCLUSION: The results of this study indicate that estimates of MNV are comparable in multiple institutions, and we recommend that they be used to support subjective histologic grading.

Cell Nucleus↗

[Usefulness of washout rate analysis in adenosine triphosphate-stress thallium-201 myocardial scintigraphy in patients with vasospastic angina].

OBJECTIVES: This study evaluated the usefulness of washout rate analysis in adenosine triphosphate(ATP) stress thallium-201 scintigraphy for the diagnosis of vasospastic angina. METHODS: This study included 76 patients with vasospastic angina and 18 normal controls undergoing coronary arteriography. If significant coronary artery stenosis (> or = 50%) was pointed out, the subject was excluded from this study. 111 MBq of thallium-201 was intravenously injected 3 min after ATP loading (0.16 mg/kg/min) was started. Single photon emission computed tomography (SPECT) was performed 10 min and 4 hr after intravenous injection of ATP. The mean washout rate (%) was calculated based on a bull's eye map and was divided into 3 regions, the antero-septal/lateral/inferior regions. The washout rate in each region was calculated. Regional uptake was visually estimated based on the 17 segments of SPECT images. RESULTS: The washout rate in the normal control group was 48.9 +/- 4.1 (mean +/- SD)%. In patients with vasospastic angina, the washout rate in areas with coronary vasospasm was 33.4 +/- 5.5%. This value was significantly lower than in the areas without coronary vasospasm (42.8 +/- 3.6%). The usefulness of washout rate analysis in the diagnosis of vasospastic angina with a cut-off value of less than -2SD from normal washout rate in the 3 regions was examined. A significantly higher diagnostic value was found by washout rate analysis (sensitivity 72.3%, specificity 79.7%, and accuracy 74.6%) compared with visual evaluation of early images (sensitivity 50.3%, specificity 73.9%, and accuracy 57.5%). CONCLUSIONS: The diagnostic value of washout rate analysis was significantly higher (73.1%) compared with visual evaluation of early images (50.3%) in patients with multivessel vasospastic angina.

Adenosine Triphosphate↗

Influence factors on the development of obesity in 3-year-old children based on the Toyama study.

BACKGROUND: Obesity in childhood increases the risk of obesity in adulthood. Obesity in adulthood is a risk factor for chronic diseases such as hypertension and atherosclerosis. Therefore, it is important to eliminate factors influencing the development of obesity in children from the viewpoint of preventive medicine. The purpose of this study is to elucidate the relationship between obesity and lifestyle in 3-year-old children in a case-control study. METHODS: Subjects were selected from the Toyama study at health checkups for 3-year-old children which are done routinely by local governments in Japan on all children of that age. A special questionnaire consisting of items on lifestyle and environmental factors of the children and past histories of parents was distributed to the Toyama study participants beforehand and was collected at the checkup. Matched-pair comparisons were performed between obese children whose body mass index was 18 or more (N = 427) and control children (N = 854) matched by sex and birth month. Multivariate stepwise conditional logistic regression analysis was also applied to assess the influence of confounding factors. RESULTS: The following six factors significantly influenced the development of obese 3-year-old children using the Mantel-Haenszel method: the mother's job, limited playtime outdoors (1 hour or less), snacking irregularity, an overweight father (body mass index >/= 24), an overweight mother (body mass index >/= 24), and overweight at birth (birth weight >/= 3,500 g). An overweight mother or father, limited playtime outdoors, overweight at birth, and snacking irregularity were significantly related to obesity in 3-year-old children after adjusting for confounding factors by multivariate stepwise conditional logistic regression analysis. CONCLUSIONS: We have suggested several factors influencing the development of obesity in 3-year-old Japanese children: parental overweight and overweight at birth as host factors, physical inactivity and snacking irregularity as behavioral factors, the mother's job as an environmental factor.

Body Mass Index↗

Economic evaluation of alternative indicators for screening for diabetes mellitus.

BACKGROUND: the optimal indicator for screening for diabetes mellitus without relying on fasting conditions was clarified. METHODS: the subjects were 891 men ages 26 through 80 years (48.5 +/- 8.5). The objectives of this study were (1) to elucidate the efficacy of 1,5-anhydroglucitol (1,5-AG), glycosylated hemoglobin, and fructosamine (FRA) as screening tests for non-insulin-dependent diabetes mellitus (NIDDM) or for impaired glucose tolerance (IGT) and (2) to perform an economic evaluation for each indicator. The efficacy of each indicator was evaluated by drawing the receiver operating characteristic curves and calculating the areas under these curves (AUCs). An original model was developed for the pur pose of cost-effectiveness analysis. RESULTS: each indicator was evaluated as a screening test for NIDDM alone and for both IGT and NIDDM. The AUCs of 1,5-AG and fasting plasma glucose were the largest in the case of the detection of NIDDM alone and the detection of both IGT and NIDDM, respectively. FRA was, however, the most cost-effective in Japan. CONCLUSION: using equations, we indicated the equi librium points at which the cost-effectiveness ratios of each indicator intersected in order to generalize the results. By calculating the appropriate-actual ratios of costs for each indicator, we could ascertain the optimal indicator for each country.

Adult↗

Temporal course of the development of obesity in Japanese school children: a cohort study based on the Keio Study.

OBJECTIVE: To demonstrate the temporal course of obesity development in Japanese school children by conducting a school-site cohort study over 12 years. METHODS: From 1981 to 1984, height and weight of 479 subjects (343 boys and 136 girls) were measured every year from entrance into primary school until graduation from high school in Tokyo. Obese children were defined as those with a body mass index (BMI) at or above the age-sex-specific standard value, derived from Japanese nationwide data. RESULTS: Approximately 50% of the children who were obese in the primary school period were obese at age 17. Likewise, 40% who were obese in the junior high school period and 70% who were obese in the high school period were obese at age 17. Among 44 children who were obese at age 17, 14 showed tracking of obesity from the preschool period, 14 showed tracking from ages 7 to 11 years, 10 showed tracking from the junior high school period, and 6 showed tracking from the high school period. CONCLUSIONS: Among children who were obese at age 17, most tracked from the primary school age or earlier. The earlier the tracking commenced, the greater the BMI at age 17. This indicates the importance of conducting health education for school children at an early age.

Adolescent↗

Granulomatous nephritis as a complication of intrarenal bacille Calmette-Guérin therapy.

A case of granulomatous nephritis after intrarenal bacille Calmette-Guérin (BCG) therapy is reported. High fever greater than 38.5 degrees C lasted for 1 month, without response to conservative therapy. Standard nephroureterectomy was subsequently carried out. Histopathologic findings from the surgical specimen were compatible with BCG-induced granulomatous nephritis. The use of a syringe pump for retrograde instillation of BCG was thought to be the major cause of this severe complication.

Aged↗

Orthotopic ileal neobladder in male patients: functional outcomes of 66 cases.

BACKGROUND: Orthotopic urinary diversion has become the preferred form of bladder reconstruction after cystectomy. We report on our experience with 66 male patients undergoing this procedure from November 1990 to February 1998. METHODS: A neobladder was constructed using an ileal segment with a Hautmann type bladder. Complications were assessed and subdivided into early and late types. Voiding function was evaluated in terms of voiding pattern and continence. Median follow up was 19.5 (range 3.5-87.7) months. RESULTS: There was one (1.5%) perioperative death. The most frequent pouch-related and unrelated early complications were persistent urine leak (7.6%) and prolonged ileus (16.7%), respectively, the majority of cases of which were managed conservatively. Analysis of late complications revealed 6.2% ureteroileal stenosis and 1.5% urethrointestinal stenosis rates, but no case of bladder stone formation. Of the 61 patients in whom voiding function was evaluable, 95.1% achieved excellent daytime continence, while only 67.2% had night-time continence. With regard to posture at voiding, 23 (37.7%) voided in a sitting position. Three of the patients (4.9%) were unable to void and required regular intermittent catheterization. CONCLUSIONS: An orthotopic neobladder can be constructed with acceptable morbidity and excellent functional results. We believe that orthotopic urinary diversion offers an attractive alternative to a bladder substitute when cystectomy is required.

Adult↗

Prognostic significance of flow cytometric deoxyribonucleic acid analysis for patients with superficial bladder cancers: a long-term follow-up study.

Flow cytometric DNA ploidy analysis for human bladder cancers may provide significant diagnostic and prognostic potential. We have previously reported that combined use of histologic and flow cytometric parameters may offer additional information regarding the clinical outcome for bladder cancer patients. However, the evaluation included both superficial and muscle-invasive tumors. In the present manuscript, we present our study on whether flow cytometric determination yields significant prognosticators beyond the classical histologic evaluation only in the patient with superficial bladder cancer. A total of 217 patients with untreated bladder cancer were evaluated, using fresh bladder tumor specimens. Tumor grading (grade 1, 2, and 3) and stage (pTa + pT1a and pT1b) served as the histologic prognostic parameters. Multiple flow cytometric parameters assessed included DNA index, percentage S-phase cells, percentage G2/M-phase cells, and hypertetraploid cell presence. Multivariate survival analysis was performed using the SAS proportional hazard regression procedure to study statistical individual prognostic values of both the histologic and the flow cytometric parameters. Clinical follow-up of more than 60 months was required, with the mean follow-up being 116.3 +/- 18.6 months. Hypertetraploid cell presence was the single most important prognostic factor (p < 0.01; risk ratio: 14.3), with the second being tumor grade (p < 0.05; risk ratio: 4.6). No other parameters, including tumor stage, the DNA index, and cell phase fractions, contributed to the model. These results indicate that hypertetraploid cell presence found by flow cytometric determination may provide additional information regarding the clinical outcome for superficial bladder cancer patients, and can be used as an indicator for decision making in treatment of superficial bladder cancer patients.

Aged↗

New approach in the evaluation of a fitness program at a worksite.

The most common methods for the economic evaluation of a fitness program at a worksite are cost-effectiveness, cost-benefit, and cost-utility analyses. In this study, we applied a basic microeconomic theory, "neoclassical firm's problems," as the new approach for it. The optimal number of physical-exercise classes that constitute the core of the fitness program are determined using the cubic health production function. The optimal number is defined as the number that maximizes the profit of the program. The optimal number corresponding to any willingness-to-pay amount of the participants for the effectiveness of the program is presented using a graph. For example, if the willingness-to-pay is $800, the optimal number of classes is 23. Our method can be applied to the evaluation of any health care program if the health production function can be estimated.

Cost-Benefit Analysis↗

The role of volume-weighted mean nuclear volume in predicting disease outcome in patients with prostate cancer treated with radical prostatectomy.

BACKGROUND: Estimates of volume-weighted mean nuclear volume (MNV) are the only means by which unbiased estimates of three-dimensional parameters can be obtained from single two-dimensional sections without any assumptions. We have reported that for prostate cancer estimates of MNV are prognostically equal or superior to morphological grading of malignancy, such as Gleason score (GS), and in particular, that MNV proved to be a meaningful predictor of prognosis for patients with clinically localized tumors. However, all previous studies were conducted on patients treated conservatively, and no authors have tested whether estimates of MNV can predict the prognosis of patients treated with radical prostatectomy. MATERIALS AND METHODS: A retrospective prognostic study of 52 patients with clinically localized prostate cancer diagnosed at three Hospitals in Shizuoka Prefecture, Japan (Shizuoka City Hospital, Shizuoka Prefectural Hospital and Shimada Municipal Hospital) and treated by radical prostatectomy was performed. Twenty of these patients were treated with hormone therapy before radical prostatectomy. Unbiased estimates of MNV were compared with clinical stage, histological grading according to GS and neo-adjuvant hormone therapy with regard to the prognostic value. RESULTS: MNV was significantly correlated with pathological T stage, but was not significantly correlated with the presence or absence of lymph node metastasis. Univariate analysis revealed that MNV correlated significantly with progression-free survival (p = 0.0116). Multivariate analysis revealed that MNV (p = 0.0115) and GS (p = 0.0275) were two significant independent predictors of progression-free survival. CONCLUSIONS: The results of the present study suggest that MNV and GS are powerful independent predictors of prognosis for prostate cancer treated with radical prostatectomy. We recommend estimates of MNV as a supportive method to the histological grading for patients with prostate cancer.

Antineoplastic Agents↗

The role of volume-weighted mean nuclear volume in predicting disease outcome in patients with stage M1 prostate cancer.

BACKGROUND: Various factors have been reported to be of value in predicting the prognosis of prostate cancer. Gleason score (GS) and prostate-specific antigen (PSA) are the two most powerful prognosticators among them. We previously reported that estimation of volume-weighted mean nuclear volume (MNV) was a more useful prognosticator for prostate cancer than subjective histologic grading. In this study, we compared estimates of MNV with PSA and GS for predicting the prognosis of stage M1 prostate cancer. EXPERIMENTAL DESIGN: A retrospective prognostic study of 66 patients with stage M1 prostate cancer diagnosed between January 1989 and December 1996 at Shizuoka City Hospital and Shizuoka Prefectural Hospital was performed. The prognostic value of unbiased estimates of MNV were compared with PSA and histologic grading according to GS. RESULTS: Univariate analysis revealed that estimates of MNV (p=0.0136) and post-treatment nadir PSA level (p<0.0001) correlated significantly with the prognosis of stage M1 prostate cancer, whilst GS (p=0.9377), pre-treatment PSA level (p=0.7377) and rate of decrease in PSA level within 1 month after the beginning of therapy (p=0.8999) had no prognostic value. Multivariate analysis revealed that post-treatment PSA level and estimates of MNV were the two most powerful prognosticators. CONCLUSIONS: This study indicates that estimation of MNV is an important prognosticator, in conjunction with post-treatment nadir PSA level, in stage M1 prostate cancer.

Aged↗

Clinical characteristics of amiodarone-induced thyrotoxicosis and hypothyroidism in Japan.

Since amiodarone was introduced in Japan in 1992, the incidence of the drug-induced thyroid dysfunction has been increasing. We studied the thyroid function of 13 patients with amiodarone-induced thyrotoxicosis (AIT) and 11 patients with amiodarone-associated hypothyroidism (AAH) who had been referred to our Institute in the last 6 years. AIT and AAH developed after 39+/-21 and 20+/-16 months of amiodarone treatment, respectively. One patient developed AAH followed by AIT. The AIT ranged from subclinical to overt thyrotoxicosis. Four patients with moderate to marked AIT were treated with methimazole. Their thyrotoxicosis persisted for 3 to 9 months, despite administration of antithyroid agents. One patient with mild thyrotoxicosis was treated with prednisolone, resulting in a euthyroid state in a few months. Eight patients with asymptomatic to moderate thyrotoxicosis resolved spontaneously without any treatment. In four asymptomatic patients with AIT, serum levels of T3 and T4 were in the upper normal range or slightly high (< 12 microg/dl), accompanied by suppressed TSH (<0.1 microU/ml) and high thyroglobulin levels, suggesting destruction-induced thyrotoxicosis. Such a subclinical thyrotoxicosis developed repeatedly in one patient. Ultrasonographic studies revealed no nodular lesion in the thyroid, and color flow Doppler sonography demonstrated no hypervascularity in the thyroid gland in any AIT patient. Although it is postulated in Europe that there are two types of AIT, namely type I, which develops in patients with latent Graves' disease or toxic multinodular goiter, and type II, which develops in an apparently normal thyroid as destructive thyroiditis, all AIT patients we have seen so far had developed destructive type AIT. Sufficient intake of iodide and a very low incidence of toxic multinodular goiter may account for the rare incidence of type I AIT in our country. Mild to moderate AIT resolved spontaneously without discontinuing amiodarone, but it was discontinued in two of 13 AIT patients because of extrathyroidal adverse reactions.

Adult↗