Biomedical subjects

Yoshihiro Okumura

Publications and source records attributed to Yoshihiro Okumura.

13 recordsLinked to original sources

PubMed2006

Customizable neuroinformatics database system: XooNIps and its application to the pupil platform.

The developing field of neuroinformatics includes technologies for the collection and sharing of neuro-related digital resources. These resources will be of increasing value for understanding the brain. Developing a database system to integrate these disparate resources is necessary to make full use of these resources. This study proposes a base database system termed XooNIps that utilizes the content management system called XOOPS. XooNIps is designed for developing databases in different research fields through customization of the option menu. In a XooNIps-based database, digital resources are stored according to their respective categories, e.g., research articles, experimental data, mathematical models, stimulations, each associated with their related metadata. Several types of user authorization are supported for secure operations. In addition to the directory and keyword searches within a certain database, XooNIps searches simultaneously across other XooNIps-based databases on the Internet. Reviewing systems for user registration and for data submission are incorporated to impose quality control. Furthermore, XOOPS modules containing news, forums schedules, blogs and other information can be combined to enhance XooNIps functionality. These features provide better scalability, extensibility, and customizability to the general neuroinformatics community. The application of this system to data, models, and other information related to human pupils is described here.

Computational Biology↗

PubMed2006

Reduced cardiac uptake and enhanced washout of 123I-MIBG in pure autonomic failure occurs conjointly with Parkinson's disease and dementia with Lewy bodies.

UNLABELLED: The purpose of this study was to investigate myocardial uptake of 123I-metaiodobenzylguanidine (MIBG) in patients with pure autonomic failure (PAF), which has pathologic features in common with idiopathic Parkinson's disease (IPD) and dementia with Lewy bodies (DLB). METHODS: Six patients with PAF, 130 with IPD, 21 with DLB, 9 with corticobasal degeneration (CBD), 11 with progressive supranuclear palsy (PSP), and 11 with multiple-system atrophy (MSA) underwent myocardial 123I-MIBG scintigraphy, as did 16 control patients. RESULTS: Resulting heart-to-mediastinum (H/M) ratios were significantly lower in patients with PAF, IPD, or DLB than in patients with CBD, PSP, or MSA and in the controls. H/M ratios were lower for delayed images than for early ones in patients with PAF, IPD, or DLB, whereas the ratios were higher for delayed images in patients with CBD and in the controls. CONCLUSION: Cardiac sympathetic denervation and enhanced washout of 123I-MIBG from sympathetic nerve terminals may develop in parallel in patients with PAF, IPD, or DLB.

3-Iodobenzylguanidine↗

PubMed2005

Diagnostic capabilities of I-131, TI-201, and Tc-99m-MIBI scintigraphy for metastatic differentiated thyroid carcinoma after total thyroidectomy.

We investigated the diagnostic capabilities of I-131, Tl-201, and Tc-99m-MIBI (hexakis-2-methoxyisobutyl- isonitrile) scintigraphy for thyroid cancer metastases after total thyroidectomy over the entire body and for every locus before and after thyroid bed ablation. After total thyroidectomy of thyroid cancer, 36 cases were subjected to I-131 treatment 64 times. They consisted of 17 men and 19 women with 31 papillary carcinomas and 5 follicular carcinomas. Their ages were 22--75(an average of 60.5+/-12.3) years. I-131 scintigraphy(I-131), Tl-201 scintigraphy(Tl-201), and Tc-99m- MIBI scintigraphy (Tc-99m-MIBI) were performed. We defined the metastases as those cases in which serum thyroglobulin (Tg)increased significantly or in which we were able to prove the lesions on CT (computed tomography), MRI (magnetic resonance imaging) or bone scintigram. Three radiology medical specialists visually evaluated each scintigram and calculated the sensitivity, specificity, and likelihood ratio. For whole-body sensitivity, both Tl-201 and Tc-99m-MIBI were high before ablation and I-131 was high after ablation. Before ablation, the negative likelihood ratio was less than 0.1 for Tl-201 and Tc-99m-MIBI, while the positive likelihood ratio was more than 10 for Tl-201. After ablation, the positive likelihood ratio for I-131, Tl-201, and Tc-99m-MIBI was more than 10. The sensitivity of the mediastinum was appropriate, except for I-131 before ablation, and the sensitivity of the lung before and after ablation was inferior for either tracer. The specificity of the cervix for I-131 before ablation was markedly deteriorated, but it increased after ablation.

Adenocarcinoma, Follicular↗

PubMed2004

Differentiation of thyroid nodules using Tl-201 scintigraphy quantitative analysis and fine-needle aspiration biopsy.

We studied the differentiation of thyroid nodules using fine-needle aspiration biopsy (FNA) and Tl-201 scintigraphy quantitative analysis. One-hundred and thirty-one thyroid nodules were examined: 83 follicular lesions (58 benign and 25 malignant lesions) and 48 non-follicular lesions (8 benign and 40 malignant lesions). During Tl-201 scintigraphy examinations, an early and a delayed image were acquired 10 and 120 min after an intravenous injection, respectively. The T/N ratio (counts of nodular lesion/counts of contralateral normal thyroid tissue) of each image was calculated quantitatively. We assessed the ability of the Tl-201 scintigraphy and of the FNA analysis to differentiate benign and malignant lesions and determined the cut-off levels for the assays. For the follicular lesions, the area under the ROC (Receiver Operating Characteristic) curve (Az) for the Tl-201 scintigraphy data was greater than that for the FNA data. For the non-follicular lesions, the Az for the FNA data was greater than that for the Tl-201 scintigraphy data. We set cut-off levels at 1.370 for follicular lesions, and 1.070 for non-follicular lesions. The sensitivity and specificity were 76% and 82.7% for follicular lesions, and 90% and 87.5% for non-follicular lesions, respectively. The overall accuracy of the analysis was 84.0%.

Adenoma↗

PubMed2004

Functional evaluation of lung by Xe-133 lung ventilation scintigraphy before and after lung volume reduction surgery (LVRS) in patients with pulmonary emphysema.

We evaluated the respiratory functions of patients with pulmonary emphysema who underwent lung volume reduction surgery (LVRS) by the mean transit time (MTT) with Xe-133 lung ventilation scintigraphy, forced expiration volume in 1 sec (FEV1.0), residual volume (RV), distance walked in 6 min (6-min walk), and the Hugh-Jones classification (H-J classification) before and after LVRS. In 69 patients with pulmonary emphysema (62 men, 7 women; age range, 47-75 years; mean age, 65.4 years +/- 6.1, preoperative H-J classification, III (two were II)-V) who underwent LVRS, all preoperative and postoperative parameters (MTT 3 weeks after LVRS and the others 3 months after LVRS) were judged statistically by the Wilcoxon signed-ranks test and Odds ratio. Every postoperative parameter was improved with a significant difference (P < 0.05) compared to preoperative parameters. MTT at 3 weeks after LVRS was not associated with %FEV1.0 and the H-J classification at 3 months after LVRS, but was associated with RV and a 6-min walk at 3 months after LVRS. MTT was useful for the clinical evalution of aerobic capability after LVRS.

Aged↗

PubMed2004

pEYFP-Nuc vector is a useful tool for three-dimensional and time-lapse observation of nuclear morphology of Jurkat cells during apoptosis.

Using a pEYFP-Nuc vector, which contains nucleic acid sequences of a nuclear localization signal, we established a Jurkat-YN cell line that expressed enhanced yellow fluorescent protein (EYFP) in the nucleus. We observed three-dimensional and time-lapse changes in nuclear morphology of Jurkat-YN cells during Fas-induced apoptosis using a confocal laser scanning microscope. The nuclear forms visualized by EYFP were almost equal in quality to those visualized by SYTO59, a nucleic acid stain for living cells. Three-dimensional deformities in the nuclear form were observed during apoptosis before chromatin condensation became apparent, indicating these deformities are characteristic morphological changes of the early stage of apoptosis. In conclusion, the pEYFP-Nuc vector is a useful tool in the time-lapse observation of nuclear morphology of living cells during apoptosis.

Antibodies, Monoclonal↗

PubMed2004

Cepharanthine enhances in vitro and in vivo thermosensitivity of a mouse fibrosarcoma, FSa-II, based on increased apoptosis.

Cepharanthine (Ce) is a biscoclaurine alkaloid extracted from Stephania cepharantha Hayata. In our previous study, Ce significantly enhanced thermosensitivity and thereby reduced thermotolerance in vitro, and intra-peritoneal injection of Ce slightly enhanced thermosensitivity in vivo. In the present study, we investigated Ce's effect in vitro on the pattern of cell death after heating and the effect of intra-tumoral injection of Ce on in vivo thermosensitivity using a mouse fibrosarcoma, FSa-II, and C3H/He mice. Ce significantly enhanced the in vitro thermosensitivity of FSa-II cells with heating at 44 degrees C, with increased Ce concentration. Time-lapse microscopic observation of individual cells confirmed that Ce treatment hastened both apoptosis (specifically, apoptotic budding) and necrosis (as indicated by staining with propidium iodide). Staining with annexin V-enhanced green fluorescent protein indicated that Ce used concomitantly with heating significantly increased the proportion of cells in the early stage of apoptosis. Ce combined with heating also significantly increased the proportion of cells with high intracellular caspase-3 activity, as detected by a substrate of caspase-3, PhiPhiLux-G1D2. The intra-tumoral injection of Ce, followed by heating at 44 degrees C, significantly delayed in vivo tumor growth, and this delay increased in a Ce concentration-dependent manner. Ce injected 30 min before heating delayed tumor growth more than Ce injected immediately before heating. These findings suggest the potential of Ce as a thermosensitizer to increase apoptosis of tumor cells.

Alkaloids↗

PubMed2003

Hepatectomy simulation discrepancy between radionuclide receptor imaging and CT volumetry: influence of decreased unilateral portal venous flow.

BACKGROUND: Regional dysfunction demonstrated by Tc-99m-diethylenetriamine-penta-acetic acid-galactosyl human serum albumin (GSA) scintigraphy due to regional decrease in the portal venous flow has previously been reported. In this study, we call attention to the significance of unilateral portal venous flow decrease for preoperative hepatectomy simulation, and evaluate the hepatectomy simulation discrepancy between Tc-99m-GSA single-photon emission computed tomography (SPECT) and CT volumetry. METHODS: Twenty-four hepatectomy candidates underwent preoperative hepatectomy simulation by both Tc-99m-GSA SPECT and CT volumetry. Both anatomical and functional resection ratios were calculated by means of CT volumetry and Tc-99m-GSA SPECT, respectively. The differences and ratios between anatomical and functional resection ratios were calculated in all patients, and compared in patients with and without unilateral portal venous flow decrease. RESULTS: Anatomical resection ratios were 28.0 +/- 11.7 (mean +/- standard deviation) in patients with unilateral portal venous flow decrease, and 42.1 +/- 15.7 in patients without unilateral portal venous flow decrease (p = 0.0127). Functional resection ratios were 14.7 +/- 12.8 in patients with unilateral portal venous flow decrease and 40.5 +/- 14.6 in patients without (p = 0.0004). The differences between anatomical and functional resection ratios were 13.0 +/- 7.9 in patients with unilateral portal venous flow decrease and 5.6 +/- 3.1 in patients without (p = 0.0099). The ratios between anatomical and functional resection ratios were 0.48 +/- 0.29 in patients with unilateral portal venous flow decrease and 0.86 +/- 0.10 in patients without (p = 0.0018). In 12 of the 13 patients with unilateral portal venous flow decrease, anatomical resection ratios were found to be larger than functional resection ratios, whereas this happened in only 6 of 11 patients without unilateral portal venous flow decrease (p = 0.0063). CONCLUSION: Unilateral portal venous flow decrease is suspected to be a major factor in the discrepancy between hepatectomy simulations with radionuclide receptor imaging and CT volumetry.

Adult↗

PubMed2003

Quantitative evaluation by Tl-201 scintigraphy in the diagnosis of thyroid follicular nodules.

We examined the diagnostic capability of a quantitative evaluation by determining the optimum area for comparisons with nodule and optimum imaging time by Tl-201 scintigraphy in thyroid follicular nodules, retrospectively. Ninety-one thyroid follicular nodules, for which the pathological diagnosis had been established, were examined (60 benign, 31 malignant). After 74 MBq of Tl-201 chloride was injected intravenously, Tl-201 scintigrams were obtained at 10, 20, 30, and 120 min. For the quantitative evaluation, the area with the greatest accumulation in the nodule and a comparative region in the contralateral thyroid and the soft tissues in the cervical region were manually selected as the region of interest (ROI) referring to Tc-99m pertechnetate scintigrams and ultrasonographic findings as a guide by two radiologists, and the T/N ratio (tumor/normal tissue ratio) and T/S ratio (tumor/soft tissue ratio) were calculated. The pixel counts were determined for all ROI. A summary index of overall test performance can be calculated as the area under the receiver operating characteristic (ROC) curve (Area (Az)), and the likelihood ratios were also calculated. We estimated the cut-off on a fitted binormal ROC curve. Multiple regression analyses were used to investigate the relationships between the optimum quantitative evaluation and 5 independent variables. A p value below 5% was considered to be significant. The T/N ratio and T/S ratio were significantly higher in the malignant group at 10 min (0.844 and 0.702), 20 min (0.844 and 0.704), 30 min (0.841 and 0.670), and 120 min (0.887 and 0.733), respectively (p < 0.01). The Az for the T/N ratio was greatest at 120 min. The multiple regression analysis showed that only 'benign or malignant' was a significant variable in the T/N ratio at 120 min. It correlated significantly in interobserver (r = 0.80) and intraobserver (r = 0.80) studied (p < 0.001). An assessment of the cut-off value of the T/N ratio at 120 min, at the cut-off of 1.255, the likelihood ratio for positive test result was greatest at 8.56, while at the cut-off of 1.010, the likelihood ratio for negative test result was lowest at 0.165. The T/N ratio at 120 min was more useful than the other condition to distinguish between benign and malignant thyroid follicular nodules.

Adenocarcinoma, Follicular↗

PubMed2003

Comparison of Tc-99m-GSA scintigraphy with hepatic fibrosis and regeneration in patients with hepatectomy.

OBJECTIVE: Liver regeneration after hepatectomy is correlated with liver fibrosis. Retrospectively, we compared three quantitative indices (HH15, LHL15 and LU15) of Technetium-99m-diethylenetriaminepentaacetic acid-galactosyl-human serum albumin (Tc-99m-GSA) liver scintigraphy with liver fibrosis; in particular, we compared the HH15 index and the rate of remnant liver regeneration. METHODS: Fifty-three patients who had undergone hepatectomy were enrolled in this study. The non-neoplastic parts of their resected specimens were divided into 5 groups (F0-F4) according to the degree of liver fibrosis, as determined using the New Inuyama classification system: F0, no fibrosis (n = 12); F1, portal fibrosis widening (n = 12); F2, portal fibrosis widening with bridging fibrosis (n = 14); F3, bridging fibrosis plus lobular distortion (n = 7); F4, liver cirrhosis (n = 8). RESULTS: When the cases were divided into a no or mild fibrosis group (F0 and F1) and a moderate or severe fibrosis or cirrhosis group (F2, F3 and F4), all of the indices were significantly different between the two groups. In this analysis, the areas (Az) under the receiver operating characteristic (ROC) curves for the HH15 and LHL15 indices were very similar, while the Az for the LU15 index was smaller. An HH15 index equal to 0.52 was the most accurate, producing a 79.3% sensitivity and a 75.0% specificity rating. When 18 patients that had received a CT scan one month after hepatectomy were divided into 2 groups according to their HH15 value (group A, HH15 < or = 0.52; group B, HH15 > 0.52), group A exhibited a better regeneration rate. CONCLUSION: Tc-99m-GSA scintigraphy is well correlated with liver fibrosis and may be useful for non-invasive, preoperative evaluations of liver fibrosis. The HH15 index, in particular, may be useful for predicting the rate of liver regeneration after hepatectomy.

Adult↗

PubMed2002

The usefulness of serum thyroglobulin levels and Tl-201 scintigraphy in differentiating between benign and malignant thyroid follicular lesions.

OBJECTIVE: To compare the diagnostic capabilities of various serum thyroglobulin levels (Tg) and Tl-201 scintigraphy with regard to thyroid follicular lesions. METHODS: We examined 80 thyroid follicular lesions (benign: 55, malignant: 25) in patients with nodular goiter for whom a pathological diagnosis was made based on surgical findings. Tg was measured by an I-125 (radioimmunoassay) method. In Tl-201 scintigraphy, 74 MBq of Tl-201 chloride was intravenously injected and imaged after 10 minutes (early image) and after 120 minutes (delayed image), and the scintigrams were evaluated both visually and quantitatively, with special attention paid to the part of the nodule with the highest accumulation of Tl-201 chloride. The cutoff levels of Tg for categorizing the lesions as malignant were set at 40, 100, 300, 500, 1,000 and 2,500 microg/l. In Tl-201 scintigraphy, method I involved high uptake on both early and delayed images, method 2 involved high uptake on only the early image, and method 3 involved high uptake on only the early image or the same accumulation in comparison with the normal region on the early image, with no washout being quantitatively judged as indicative of malignancy. A summary index of overall test performance can be calculated as the area under the receiver operating characteristic (ROC) curve (Area (Az)). Likelihood ratios for several cutoff levels were also calculated. RESULTS: In the diagnosis, Az of Tl-201 (0.95),was larger than that of Tg (0.65). The sensitivity and accuracy of Tg at each cutoff level (sensitivity: 4.0% to 76.0%, accuracy: 50.0% to 72.5%) were lower than with Tl-201 scintigraphy (methods 1-3, sensitivity: 76.0-100%, accuracy: 77.5-88.8%). The likelihood ratio for the positive results of method 1for Tl-201 scintigraphy, were greatest in the present study (13.9), and the likelihood ratio for the negative results of method 3 for Tl-201 scintigraphy, (0) was smallest in the present study. CONCLUSION: Diagnosis based on Tl-201 washout patterns in which quantitative evaluation is combined with visual evaluation appears to be more useful for the differentiation of malignant thyroid follicular lesions than diagnosis by Tg.

Adolescent↗

PubMed2002

Transcatheter embolization of an aortobronchial fistula with N-butyl cyanoacrylate.

Aortobronchial fistula is a fatal complication after thoracic aortic surgery. So far, treatment options for aortobronchial fistula have included surgical and endovascular stent-graft methods. Herein, a case of an aortobronchial fistula with life-threatening hemoptysis managed with transcatheter embolization of the fistula with N-butyl cyanoacrylate is reported. For the patient with an aortobronchial fistula who cannot be treated by surgical or endovascular stent-graft methods, transcatheter embolization of the fistula may be the only available life-saving method.

Aged↗

PubMed2002

Regional radioactivity discrepancy between Tc-99m GSA and Tc-99m phytate liver scans in a patient with massive hepatic necrosis.

A 22-year-old woman with severe acute hepatitis underwent a Tc-99m galactosyl human serum albumin (GSA) scan. Intense accumulation was observed in the cephalic region of the right hepatic lobe, whereas the accumulation was reduced in the left lobe and the caudal region of the right lobe. A computed tomographic (CT) scan showed that the left lobe and the caudal region of the right posterior segment had atrophied and become hypodense, which were thought to represent postnecrotic scarring after massive hepatic necrosis. The relatively hyperdense region in the right lobe was slightly swollen and was thought to represent regenerating liver tissue or a "potato liver." Compared with the CT, the regions of elevated Tc-99m GSA accumulation correlated well with the areas of regenerating liver tissue, and the regions with reduced accumulation corresponded closely with the areas of postnecrotic scarring. On a Tc-99m phytate scan, unlike the Tc-99m GSA scan, the radiocolloid accumulation was intense in the left lobe and caudal region of the right lobe and reduced in the cephalic region of the right lobe. Together, the Tc-99m GSA scan and the Tc-99m phytate scan formed a set of exact "nega-posi" images. Biopsy specimens obtained during laparoscopy showed a few hepatocyte columns in the postnecrotic scarred left lobe. Severe disruption of the hepatocytes, prominent inflammatory cell infiltration, and obvious Kupffer cell hypertrophy and clustering were also observed.

Acute Disease↗