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Biomedical subjects

S Takashima

Publications and source records attributed to S Takashima.

At least 91 records · Page 5Linked to original sources
PubMed2001

Relation of fibrillatory wave amplitude with hemostatic abnormality and left atrial appendage dysfunction in patients with chronic nonrheumatic atrial fibrillation.

Large left atrium (LA) and LA appendage (LAA) dysfunction are known to relate to cardiogenic thromboembolism, so the present study investigated the relation of the atrial fibrillatory wave (F wave) amplitude to hemostatic markers and LAA function. Transthoracic and transesophageal echocardiographic studies were performed in 82 consecutive patients with chronic, nonrheumatic atrial fibrillation (AF). Patients were divided into 2 groups according to F wave amplitude in lead V1 on the 12-lead ECG: coarse AF (the greatest amplitude of F wave > or =1 mm, n=44) and fine AF (<1 mm, n=38). Plasma levels of thrombin-antithrombin III complex, D-dimer, platelet factor 4 and beta-thromboglobulin were determined. Compared with patients with coarse AF, those with fine AF had lower LAA peak flow velocity (p<0.05) and higher prevalence of embolic cerebral infarction (50% vs 27%, p<0.05). Platelet activity did not differ between the 2 groups; however, plasma levels of thrombin-antithrombin III complex and D-dimer were significantly higher in patients with fine AF than in those with coarse AF (p<0.05). Multiple logistic regression analysis showed that fine AF was independently associated with cerebral embolism. Therefore, the presence of fine F wave in V1 would be a useful marker of LAA dysfunction and hypercoagulability, and indicate a risk for cerebral embolism in patients with chronic, nonrheumatic AF.

Aged↗
PubMed2001

Visibility of small peripheral lung cancers on chest radiographs: influence of densitometric parameters, CT values and tumour type.

The purpose of this study was to determine the effects of tumour density and tumour type on the visibility of small peripheral lung cancers on chest radiographs. We retrospectively evaluated the visibility of 63 small (< or = 20 mm) peripheral lung cancers on chest radiographs. 48 (76%) were detected in our low dose CT screening for lung cancer and 15 (24%) in routine clinical examination. Analysis was based on tumour optical contrast, gradient at the tumour margin, CT values and tumour type. There were 31 (49%) visible cancers and 32 (51%) invisible cancers on chest radiographs. Visible tumours had an optical density of 0.1-0.3 OD and a gradient of 0.03-0.11 OD mm-1. The mean size of visible tumour (14.3 mm) was larger than that of invisible tumour (11.1 mm; p < 0.001). The mean CT value (-140 HU) of visible tumour was higher than that of invisible tumour (-490 HU; p < 0.001). The detection rates of adenocarcinomas with lepidic growth (0% for type A, 29% for type B and 68% for type C) were less than those with hilic growth (100% for types D-F). All squamous and small cell carcinomas with hilic growth were visible on chest radiographs, but the numbers of each were small. In summary, tumour type influenced the contrast, gradient, CT values and margin of the tumour. Small adenocarcinomas with a lepidic tumour growth were less well seen on chest radiographs compared with small lung cancers with hilic tumour growth.

Adenocarcinoma↗
PubMed2001

A transesophageal echocardiographic study on risk factors for stroke in elderly patients with atrial fibrillation: a comparison with younger patients.

STUDY OBJECTIVES: Atrial fibrillation (AF) becomes an increasingly important cause of stroke as patients get older. The aim of the study was to determine whether risk factors of cerebral embolism among elderly patients with AF differed from those of younger patients by using transesophageal echocardiography (TEE). DESIGN AND SETTING: Cross-sectional study at a university hospital. METHODS: Cardiovascular lesions with the potential for thromboembolism in patients with AF were investigated using TEE. Left atrial spontaneous echocardiographic contrast (SEC), peak flow velocity in the left atrial appendage (LAA-flow), and aortic atherosclerosis of the thoracic aorta were assessed in 67 elderly (> or = 70 years old) and 135 younger (< 70 years old) patients. All patients underwent either brain CT (n = 54) or MRI (n = 148) to assess presence of cerebral infarction. RESULTS: Cerebral infarction due to embolism was noted in 113 patients with AF. There was a higher prevalence of cerebral embolism in elderly patients when compared with younger patients (78% vs 45%; p < 0.001). Cerebral embolism found in younger patients was associated with high grade of SEC and lower LAA-flow (p < 0.05). In addition to these TEE findings, aortic atherosclerosis was more severe in elderly patients with cerebral embolism than in those without cerebral embolism (p < 0.0001). By multivariate logistic analysis, LAA-flow was an independent predictor of cortical infarction in younger patients, but not in elderly patients, whereas aortic atherosclerosis was a useful marker in predicting embolic risk in elderly patients. CONCLUSIONS: TEE findings indicative of left atrial blood stasis were useful to identify the embolic risk of younger patients with AF, while atherosclerosis of the thoracic aorta appears to be an important marker for cerebral embolism in elderly patients.

Age Factors↗
PubMed2001

Serotonin transporter gene variation is a risk factor for sudden infant death syndrome in the Japanese population.

OBJECTIVE: Serotonin (5-HT) in the nervous system is a major factor in facilitation of the brain center for respiration. Variations in the promoter region of the 5-HT transporter (5-HTT) gene have been shown to potentially regulate 5-HT activity in the brain. Therefore, we aimed to identify the possibility that specific allele variants of the 5-HTT gene can be found as a genetic background for sudden infant death syndrome (SIDS). METHODS: Polymorphisms in the 5' regulatory region of the 5-HTT gene were determined in genomic DNA obtained from 27 SIDS victims and 115 age-matched health control participants. RESULTS: There were significant differences in genotype distribution and allele frequency of the 5-HTT promoter gene between SIDS victims and age-matched control participants. The L and XL alleles were more frequently found in SIDS victims than in age-matched control participants. CONCLUSION: Efficiency in the transportation of 5-HTT with the L allele is known to be higher than that with the S allele. The excitatory function by 5-HT is considered to be lower in the respiratory center of individuals with the L allele compared with those with S allele. The XL allele variant has shown another novel biological risk factor for SIDS.

Carrier Proteins↗
PubMed2001

High-resolution CT analysis of small peripheral lung adenocarcinomas revealed on screening helical CT.

OBJECTIVE: The purpose of this study was to determine the correlation between high-resolution CT morphologic features of small peripheral lung adenocarcinomas and tumor growth patterns. MATERIALS AND METHODS: We examined high-resolution CT morphologic features of 59 small, surgically resected peripheral lung adenocarcinomas (diameter, 6-20 mm) that were detected on screening for lung cancer using low-dose helical CT. Among these adenocarcinomas, 14 (24%) were visible and 45 (76%) were invisible on conventional chest radiography. The correlation between high-resolution CT morphologic features and tumor growth patterns was analyzed. RESULTS: Sixteen (94%) of 17 type A (Noguchi's classification) adenocarcinomas appeared as nodules of pure ground-glass attenuation (high-resolution CT type I). Ten (71%) of 14 type B tumors appeared as heterogeneous, low-attenuation nodules (type II). Seven (29%) of 24 type C tumors appeared as nodules with ground-glass attenuation in the periphery and a high-density central zone (type III), and 12 (50%) of 24 type C tumors appeared as homogeneous nodules with soft-tissue density (type IV). Among tumors with a replacement growth pattern, the size and CT values of type C tumors were larger than those of type A or type B tumors (p < 0.05), whereas the percentage of ground-glass attenuation and retained air space in type C tumors was smaller than those in type A or type B tumors (p < 0.01). All (100%) four type D tumors appeared to be homogeneous nodules with soft-tissue density (type IV). CONCLUSION: Small peripheral lung adenocarcinomas shown on CT exhibit four high-resolution CT patterns that corresponded to the histopathologic findings of different tumor growth patterns.

Adenocarcinoma↗
PubMed2001

Parotid masses: prediction of malignancy using magnetization transfer and MR imaging findings.

OBJECTIVE: We determined the most accurate criteria for predicting malignancy of masses in the parotid gland using magnetization transfer ratios. SUBJECTS AND METHODS: Lesion-to-muscle magnetization transfer ratios obtained with a spoiled gradient-recalled acquisition in a steady state sequence with a 1-kHz off-resonance pulse were measured in 72 parotid masses (52 benign lesions, 20 malignant tumors). Various MR imaging findings and lesion-to-muscle magnetization transfer ratios were simultaneously assessed using a logistic model to determine the useful factors for predicting malignancy. We also studied the clinical usage of magnetization transfer ratios. RESULTS: Of the MR imaging findings, poorly defined margins showed the highest accuracy, 81%, with 60% sensitivity and 88% specificity. Of the lesion-to-muscle magnetization transfer ratios, a ratio of greater than 0.71 was most accurate (85%), with 90% sensitivity and 83% specificity. All four recurrent tumors and 10 (91%) of 11 secondary tumors were correctly diagnosed using the magnetization transfer ratio analysis. The logistic model revealed that the margin characteristics (p = 0.084) and lesion-to-muscle magnetization transfer ratios (p < 0.001) were statistically significant predictors for malignancy. A combined criteria of poorly defined margins and a lesion-to-muscle magnetization transfer ratio of greater than 0.71 raised the accuracy to 86% and specificity to 96%, but the sensitivity decreased to 60%. CONCLUSION: A combination of MR imaging findings and lesion-to-muscle magnetization transfer ratios was the most accurate predictor of malignancy.

Female↗
PubMed2001

Tracheal invasion by thyroid carcinoma: prediction using MR imaging.

OBJECTIVE: The purpose of this study was to evaluate the accuracy of MR imaging in predicting tracheal invasion by thyroid carcinomas and to determine MR imaging criteria for diagnosing tracheal invasion. MATERIALS AND METHODS: MR imaging was performed on the normal trachea of one cadaver and 30 healthy subjects as a standard of reference. Then, MR imaging findings in 67 patients with thyroid carcinoma were reviewed and correlated with surgical and pathologic findings. A logistic regression model was used to determine which MR imaging features were significant for predicting tracheal invasion. RESULTS: Twenty-three (34%) of the 67 patients had tracheal invasion. Logistic regression model analysis revealed that significant MR characteristics for determining tracheal invasion included soft-tissue signal in the tracheal cartilage (p < 0.001), intraluminal mass (p < 0.001), and degree of tumor circumference around the trachea (p = 0.001). The highest accuracy (90%) for determining tracheal invasion was achieved using a combination of findings. A case was considered positive for tracheal invasion if there was soft-tissue signal in the cartilage, an intraluminal mass, or a tumor that abutted a circumference of the trachea of 180 degrees or greater. Using these factors resulted in seven false-positive diagnoses because soft-tissue signal in the cartilage was sometimes seen in healthy trachea. Although intraluminal mass invariably reflected deep tracheal invasion, soft-tissue signal in the cartilage rarely indicated actual cartilage invasion but rather indicated tumor extension between the cartilaginous rings. CONCLUSION: Tracheal invasion by thyroid carcinomas can be accurately diagnosed with MR imaging, and using a combination of criteria is the most accurate method of predicting this phenomenon.

Adult↗
PubMed2001

Chemoprevention of azoxymethane-induced rat colon carcinogenesis by dietary capsaicin and rotenone.

The modifying effects of dietary administration of capsaicin, which is the principal pungent capsicum fruit, and rotenone, which is a naturally occurring pesticide derived from Derris and Lonchorcarpus species, on azoxymethane (AOM)-induced colon tumorigenesis were investigated in male F344 rats. Gavage with capsaicin and rotenone significantly elevated phase II enzymes, glutathione S-transferase (GST) and quinone reductase (QR), in the liver and colon. In an aberrant crypt foci (ACF) bioassay, feeding of capsaicin and rotenone at a dose of 500 ppm for 4 weeks significantly inhibited ACF formation induced by AOM (20 mg/kg body weight, once a week for 2 weeks). In a subsequent long-term study designed to confirm the protective effects of both compounds on ACF development, one group was treated with AOM alone and four other groups received the carcinogen treatment plus diets containing 500 ppm test compounds for 4 weeks (initiation phase) and for 34 weeks (post-initiation phase). Two groups were treated with capsaicin or rotenone alone (500 ppm in diet) and one group was maintained on the basal diet. At the termination of the study, dietary exposure of capsaicin during the initiation phase was found to significantly reduce the incidence of colonic adenocarcinoma (60% vs. 24%, 60% reduction, P=0.0407). Rotenone feeding during the post-initiation phase also reduced the frequency of colonic adenocarcinoma (60% vs. 19%, 68% reduction, P=0.0226). Our results suggest that two natural compounds, capsaicin and rotenone, might be useful for the prevention of human colon cancers.

Adenocarcinoma↗
PubMed2001

[A case of Miller Fisher syndrome with pharyngeal palsy as an initial symptom].

We report herein a rare case of Miller Fisher syndrome with pharyngeal palsy as an initial symptom. A 68-year-old man admitted to our hospital with pharyngeal palsy two weeks after a respiratory infection. He subsequently developed ataxic gait, paresthesia in the upper limbs and ophthalmoplegia. Double-filtrated-plasmapheresis had been performed four times and all the symptoms subsided within two months. In the acute phase of the disease, the titers of anti-GQ1b and GT1a antibodies were elevated. The titer of anti-GT1a antibody was higher than that of anti-GQ1b antibody. Recently, the activity of serum anti-GT1a antibody has been supposed to be associated with pharyngeal palsy. In the present case, higher titer of anti-GT1a antibody compared with that of anti-GQ1b antibody could possibly cause pharyngeal palsy as an initial symptom of Miller Fisher syndrome.

Aged↗
PubMed2001

[Multimodal treatment including intraoperative irradiation for advanced pancreatic cancer with extended metastasis].

From January 1987 to December 1999, we treated 11 advanced pancreatic cancer patients with extended metastasis with multimodal treatment. Two patients received external radiation therapy (ERT) and systemic chemotherapy, 1 received intraoperative radiation therapy (IORT) and ERT and arterial infusion chemotherapy (AIC), 2 received IORT and AIC, 4 received only IORT, 2 received only AIC, and 15 did not receive any of these treatments. There was a significant difference in the survival rate between treatment and no treatment cases (median survival of 177 days and 109 days, respectively) (p = 0.04). A significant difference in the survival rate was also observed between IORT cases and no treatment cases (median survival of 212 days and 109 days, respectively) (p = 0.02). However, there was no significant difference in the survival rate between AIC cases and no treatment cases (median survival of 177 days and 109 days, respectively) (p = 0.10). Therefore, our experience suggests that multimodal treatment including intraoperative irradiation is effective for advanced pancreatic cancer patients with extended metastasis.

Adult↗
PubMed2001

[A case of craniopharyngioma with chemical meningitis as an initial symptom].

We reported a rare case of craniopharyngioma with chemical meningitis due to spontaneous rupture of the tumor. A 50-year-old woman was admitted with high fever, headache, and nausea. On physical examination, she had nuchal rigidity. The examination of her cerebral spinal fluid(CSF) revealed pleocytosis(mononuclear cell dominant), low value of glucose level and high content of protein. The feature of her CSF findings suggested tuberculosis or fungal meningitis, but bacteriologic culture of the CSF was negative. The CT scan showed an isodensity mass in the suprasellar region and a spotty calcification in the third ventricle. The MRI with gadolinium enhancement suggested that the tumor must be craniopharyngioma and that meningitis was a type of chemical meningitis due to spontaneous rupture of craniopharyngioma. The corticosteroid therapy was rather effective to the symptoms of fever and headache. Then the operation was performed by neurosurgeons, and the diagnosis of craniopharyngioma was pathologically confirmed. Spontaneous rupture of craniopharyngioma rarely occurred and was followed by chemical meningitis. This case was an extremely rare condition that presented with chemical meningitis as an initial symptom.

Craniopharyngioma↗
PubMed2001

Clinical studies on the visualization of gastric lesions using virtual CT endoscopy.

OBJECTIVE: We evaluated the clinical usefulness of virtual CT gastroendoscopy (VCTGE). METHODS: The subjects were 124 patients with endoscopically identified gastric lesions. VCTGE images were obtained using a GE-Navigator. We evaluated VCTGE in the visualization of gastric lesions for their presence and morphology. RESULTS: The detection rate of all gastric lesions by VCTGE was 76% (94 of 124 patients). The smallest detectable early gastric cancer was II c measuring 10 x 8 mm. The detection rates of each gastric lesion by VCTGE were 73% in early gastric cancer, and 90% in advanced gastric cancer. VCTGE imaging in the advanced gastric cancer was good in 12 (30%), fair in 25 (60%) and poor in 4 (10%). VCTGE imaging in early gastric cancer was good in 20 (46%), fair in 12 (27%) and poor in 12 (27%). The significance P level was 0.005 between the evaluation of the imaging of advanced and early gastric cancer. CONCLUSIONS: VCTGE visualized the characteristics of diverse gastric lesions and was considered useful for the detection and the diagnosis of these lesions.

Adult↗
PubMed2000

Neuronal expression of the fukutin gene.

Fukuyama-type congenital muscular dystrophy (FCMD), a relatively common autosomal recessive disorder in Japan, is characterized by severe congenital muscular dystrophy in combination with cortical dysgenesis (polymicrogyria). The gene responsible for FCMD encodes a novel protein, fukutin, which is likely to be an extracellular protein. Pathological study of brain tissue from FCMD fetuses revealed frequent breaks in the glia limitans and basement membrane complex. Disruption of the basal lamina in FCMD muscle was also seen. Thus, structural alteration of the basal lamina appears to play a key role in the pathophysiology of FCMD. To investigate the role of fukutin in brain anomalies, we examined fukutin mRNA expression in the human brain. Northern blot and RT-PCR analysis revealed that the fukutin gene is expressed at similar levels in fetal and adult brain, whereas its expression is much reduced in FCMD brains. Tissue in situ hybridization analysis revealed fukutin mRNA expression in the migrating neurons, including Cajar-Retzius cells and adult cortical neurons, as well as in hippocampal pyramidal cells and cerebellar Purkinje cells. However, we observed no expression in the glia limitans, the subpial astrocytes (which contribute to basement membrane formation) or other glial cells. In the FCMD brain, neurons in regions with no dysplasia showed fair expression, whereas transcripts were nearly undetectable in the overmigrated dysplastic region. These observations suggest that fukutin function may influence neuronal migration itself rather than formation of the basement membrane. Furthermore, differences in mRNA levels among neurons in early developmental stages may partially differentiate normal and abnormal regions.

Adult↗
PubMed2000

Expression of DNA-dependent protein kinase catalytic subunit and Ku80 in developing human brains: implication of DNA-repair in neurogenesis.

We investigated expression of DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and Ku80 in developing human brain, both of which have been suggested to be involved in the repair of DNA double-strand break (DSB). Their expressions were well correlated, and the highest immunoreactivity was observed in post-mitotic immature neurons in the cerebral cortex as well as in progenitors in the periventricular germinal layer. The reactivity gradually decreased during development. Our results support the notion that DSB is generated during the ontogeny of the human central nervous system.

Adolescent↗
PubMed2000

Bronchiolitis obliterans organizing pneumonia syndrome in breast-conserving therapy for early breast cancer: radiation-induced lung toxicity.

PURPOSE: Breast-conserving surgery and postoperative radiotherapy have played important roles in the treatment of early breast cancer. Bronchiolitis obliterans organizing pneumonia (BOOP) syndrome has recently been reported to be one of the complications of adjuvant radiotherapy. The purpose of this study was to determine the incidence of and risk factors for BOOP syndrome in breast cancer patients. METHODS AND MATERIALS: Between January 1996 and December 1998, 157 patients with breast cancer underwent radiotherapy after breast-conserving surgery. The criteria used for the diagnosis of BOOP syndrome were as follows: 1) radiation therapy to the breast within 12 months, 2) general and/or respiratory symptoms lasting for at least 2 weeks, 3) radiographic lung infiltrates outside the radiation port, and 4) no evidence of a specific cause. RESULTS: BOOP syndrome developed in 4 (2.5%) patients, who had fever and nonproductive cough, with patchy infiltrative shadows on chest roentgenograms which emerged between 5 and 6 months after radiotherapy. The symptoms and pulmonary infiltrates were rapidly improved by treatment with prednisone (40 mg/day), which was tapered over 2- to 5-month periods. However, BOOP syndrome relapsed in all cases during the tapering period or after withdrawal of prednisone. The eosinophil and neutrophil counts were increased and the ratios of CD4+ to CD8+ lymphocytes were elevated in bronchoalveolar lavage fluid in all four cases. There were no differences in proportions of patients by age, irradiated breast site, use of tamoxifen and/or chemotherapy, or radiation dose between those with and without BOOP syndrome. CONCLUSIONS: BOOP syndrome is considered an intractable form of lung toxicity after radiotherapy to the breast. An immunologic reaction mediated by eosinophils, neutrophils, and lymphocytes may be responsible for the development of this syndrome. Methods of prevention of BOOP syndrome should be established.

Adult↗
PubMed2000

Telomerase activity as a marker of breast carcinoma in fine-needle aspirated samples.

BACKGROUND: Telomerase activity in breast fine-needle aspiration (FNA) samples may have diagnostic utility. The purpose of this study was to compare in FNA samples of breast tumor the diagnostic accuracy as correlated with histologic final diagnosis. METHODS: Fine-needle aspiration samples were obtained from 617 patients with palpable breast tumors. Slide preparation and cytology were performed according to a uniform approach. Extracts derived from 10(3) cells from the residual cells in the syringe were used for the telomeric repeat amplification protocol (TRAP) assay. Of the original 617 patients, 220 underwent open biopsy or surgery, and 93 cancers and 127 patients' benign diseases were diagnosed by histologic examination. RESULTS: All 62 tumors that were diagnosed as "malignant" or "probably malignant" by FNA cytology were cancerous, and 50 cases (81%) showed detectable telomerase activity. Among 17 "atypical" or "indeterminate" cases, all 10 tumors with detectable telomerase activity subsequently were diagnosed as breast carcinoma whereas 6 of 7 tumors without telomerase activity were diagnosed as benign. Among the 141 "benign" or "unsatisfactory" samples, 12 of 21 cases with detectable telomerase activity subsequently were diagnosed as cancer. CONCLUSIONS: The diagnostic accuracy of telomerase activity in FNA samples is considered to be equivalent or slightly higher to that of cytology (86% vs. 70%). Detection of telomerase activity should be considered an alert for false-negative results of FNA cytology and may be useful as a diagnostic marker for breast malignancy, especially in samples cytologically undetermined to be malignant. Cancer (Cancer Cytopathol)

Adult↗
PubMed2000

Protein tyrosine kinase is not involved in the infarct size-limiting effect of ischemic preconditioning in canine hearts.

Protein kinase C (PKC) plays an important role in ischemic preconditioning (IP). Because (1) tyrosine kinase is located at the downstream of PKC for IP in the rabbit hearts and (2) we have reported that ecto-5'-nucleotidase is the substrate for PKC and plays a crucial role for the infarct size-limiting effect, we tested whether tyrosine kinase activation contributes to either activation of ecto-5'-nucleotidase or the infarct size-limiting effect of the early phase of IP in the canine heart. In dogs, the IP procedure (4 cycles of 5-minute occlusion of coronary artery) and exposure to 12, 13-phorbol myristate acetate (PMA) each activated myocardial ecto-5'-nucleotidase and Lck tyrosine kinase. Genistein (10, 30, and 100 microg. kg(-)(1). min(-)(1) IC), an inhibitor of tyrosine kinase, attenuated the activation of Lck tyrosine kinase but did not attenuate the activation of ecto-5'-nucleotidase due to either IP or PMA. In the other canine hearts, IP attenuated infarct size (49+/-5 versus 11+/-3 or 16+/-3%, P<0.01) due to 90 minutes of coronary occlusion followed by 6 hours of reperfusion, which was not blunted by 3 or 2 (30 and 100 microg. kg(-)(1). min(-)(1)) doses of genistein (infarct sizes, 15+/-4, 13+/-4, and 13+/-3%, respectively, and 17+/-3 and 15+/-4%, respectively) or lavendustin A. Tyrosine kinase does not activate ecto-5'-nucleotidase or trigger the infarct size-limiting effect of the early phase of IP in canine hearts.

5'-Nucleotidase↗