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Biomedical subjects

S Tanada

Publications and source records attributed to S Tanada.

At least 73 records · Page 4Linked to original sources
PubMed1997

Adsorption Mechanisms of Pentafluoropropanol (5FP) onto Activated Carbons Produced by Tetraethoxysilane Sol-Gel Method

2,2,3,3,3-Pentafluoro-1-propanol (5FP) has been considered a viable CFC replacement compound. However, 5FP must be recovered in order to decrease the environmental impact and save energy. Activated carbons have been used for the recovery and removal of organic solvents. From the point of view of "zero emission," 5FP and activated carbon must be completely recycled. The purpose of this study is to recycle the activated carbons and to increase the recovery efficiency of 5FP using the activated carbons (ST-ACs) which were coated with tetraethoxysilane by the sol-gel method. The amount of 5FP adsorbed onto the ST-ACs and the degree of 5FP decomposition by the ST-ACs were measured in order to estimate the relationship between the ST-AC surface and 5FP. The amount of 5FP adsorbed and the degree of 5FP decomposition indicated that the recovery of 5FP is suitable for the use with the ST-ACs. Copyright 1997 Academic Press. Copyright 1997Academic Press

Journal Article↗
PubMed1997

Adsorbability of 1,1,1,2-Tetrafluoromethane (HFC134a) onto Plasma-Treated Activated Carbon in CF4 and CCl4

The adsorbability of 1,1,1,2-tetrafluoroethane (HFC134a), which has been the CFC12 replacement, onto tetrafluoromethane and tetrachloromethane plasma-treated activated carbon (FT-ACs and CT-ACs) was investigated. It is proved that the fluorine and the chlorine, which were produced by plasma treatment, were introduced into the pores having radii greater 7.5 A and with less than 7.5 A by plasma treatment, respectively. The adsorption site of HFC134a onto activated carbon may change with the quantities of fluorine or chlorine on the surface of the activated carbon. The amount of HFC134a adsorbed per unit specific surface area of FT-ACs and CT-ACs slightly increased a little compared to the untreated activated carbon (U-AC). The amount of fluoride ion eluted before the adsorption of HFC134a from the FT-ACs increased with the increasing plasma treatment time. That after the adsorption of HFC134a from only the activated carbon with the shortest plasma treatment time decreased. The amount of chloride ion eluted before the adsorption of HFC134a from the CT-ACs increased after 15 min of plasma treatment, but decreased with 30 min of plasma treatment. The chloride ion amount from the CT-ACs decreased after the adsorption of HCF134a. These results could be explained by the Langmuir constants a and Ws, which represent the adsorption equilibrium constant and the saturated amount of HFC134a adsorbed, respectively. The ratio of fluorine and chlorine species, the adsorption type, the layer interstitial type, and the covalent type, is different based on the plasma treatment time. It is concluded that the amount of HFC134a adsorbed onto the FT-ACs and CT-ACs did not depend upon the change of pore structure by the fluorine and chlorine.

Journal Article↗
PubMed1997

Ozone Degradation by Fluoride onto Plasma-Treated Activated Carbon in CF4

The ozone degradation of fluorine was investigated using the tetrafluoromethane plasma-treated activated carbon (PT-AC). The ozone in the stratosphere has been degraded by the chloride and bromide radicals which are produced from chlorofluorocarbons and bromofluorocarbons, respectively. However, we believe that fluorine also was related to the ozone degradation. The fluoride was introduced onto the activated carbon surface by tetrafluoromethane plasma treatment. The breakthrough curve of ozone onto PT-AC was measured to elucidate the relationship between the ozone and the fluoride. The amount of ozone adsorbed/degraded onto the PT-AC was larger than the amount that was adsorbed/degraded onto the untreated activated carbon. The amount of fluoride ion eluted from the PT-AC before the adsorption/degradation of ozone was larger than that which eluted after the adsorption/degradation of ozone. These results indicated that the ozone was degraded by the fluoride on the PT-AC surface.

Journal Article↗
PubMed1997

Inclusion of Volatile Organic Compounds into Natural Cyclodextrins and Their Branched Cyclodextrins in the Gaseous Phase

The adsorption isotherms of water, the differential heat of adsorption, and the entropy of adsorbed water were investigated to elucidate the structure of stability of cyclodextrins (CyD) and branched CyD's. The amount adsorbed on branched CyD's increased with increasing relative humidity. The steep rise in the amount adsorbed at higher relative humidities indicated that the structure of branched CyD's was affected by the water molecules at these higher relative humidities. The bonding force between alpha-CyD's and water molecules was stronger than that between their branched CyD's and water, while that between beta-CyD's and water was weaker than that between their branched CyD's and water. We have used activated carbons for the recovery of organic solvents. There are polar groups on the activated carbon surface. Therefore, the recovered organic solvents were degraded by these groups. However, such polar groups are not expected for the hydroxyl groups of the CyD's. The amounts of 1,1,1-trichloroethane, benzene, and toluene included in natural CyD's and their branched CyD's were measured. The amounts of organic solvents included in the CyD's depended upon the cavity radii and the glucosyl and maltosyl functional groups of the CyD's and the radii of the organic solvent molecules.

Journal Article↗
PubMed1997

Quantitative analysis of myocardial ischemia by technetium-99m sestamibi exercise scintigraphy: a new method for change rate mapping.

In order to quantitatively assess the extent and severity of myocardial ischemia by Tc-99m sestamibi exercise myocardial scintigraphy, we developed a new method of change rate (CR) mapping and examined its efficiency. CR was calculated to divide the counts per pixel in the stress polar map by that in the rest polar map at each corresponding pixel. The CR map showed the CR values at each pixel. To correct the differences between the stress and rest images for the dose of Tc-99m sestamibi administered, the mean counts per pixel in the stress polar map and the rest map were adjusted to the same level. Regarding the regions in which the CR value was less than 1 as ischemia, we compared the abilities of the CR map and the polar map to detect coronary artery stenosis in 5 patients with angina pectoris. The sensitivity for coronary artery stenosis was 80% in the CR map, and 40% in the polar map. The specificity for both was 75%. We concluded that the CR map was effective in assessing the extent and severity of myocardial ischemia in Tc-99m sestamibi exercise myocardial scintigraphy.

Adult↗
PubMed1997

Spectral analysis applied to hepatobiliary dynamic scintigraphy with 99Tcm-N-pyridoxyl-5-methyltryptophan.

This study was performed to evaluate the application of spectral analysis (SA) to hepatobiliary dynamic scintigraphy with 99Tcm-N-pyridoxyl-5-methyltryptophan (99Tcm-PMT) in 82 patients with a wide range of liver function, and to compare it with compartment analysis (CA) and deconvolution analysis (DA). The rate of uptake of PMT by the liver from the blood (k1) obtained by SA (y, min-1) agreed well with the k1 value obtained using CA (x, min-1) (y = 1.079x + 0.000, r = 0.993, standard error of the estimate (S.E.E.) = 0.042 min-1). The mean residence time (MRT) of PMT in the liver obtained by SA (y, min) also agreed well with the MRT value obtained by DA (x, min) (y = 1.036x - 0.759, r = 0.967, S.E.E.-1.014 min) and that obtained by CA (x, min) (y = 0.859x + 1.006, r = 0.931, S.E.E. = 1.428 min). The fraction of the measured blood activity superimposed on the true liver activity (f) obtained by SA (y) correlated well with the f value obtained by CA (x) (y = 1.168x - 0.004, r = 0.924, S.E.E. = 0.043). We conclude that the application of SA to hepatobiliary dynamic scintigraphy with PMT appears to be useful in evaluating the functional status of the liver, since it facilitates the interpretation of the kinetic behaviour of PMT in the liver and allows us to extract quantitative parameters corresponding to those obtained by CA or DA.

Biliary Tract↗
PubMed1997

Diffuse cystic change of a term placenta with a normal newborn.

We recently encountered a case of term placenta with a diffuse cystic lesion of the villi. A 19-year-old primipara at 36 weeks of gestation underwent cesarean section due to breech presentation with premature rupture of the membranes; she delivered a mature male baby of 2,502 g with an Apgar score of 9/9. The placenta was 940 g in weight and 29 x 20 x 3 cm in size, and macroscopically had multiple cystic lesions (3-8 mm in diameter) that resembled hydatidiform moles. However, histopathological examination revealed that the severe hydropic change was localized in the stem villi but not remarkable in the terminal chorionic villi. Moreover, abnormal proliferation of the trophoblast was not observed. However, the hypertrophic change was observed in the vascular wall of stem villi, in which hyperplasia of smooth muscle-like cells was present. The urinary hCG levels at 1 month and 2 months after delivery were less than 50 IU/l. These findings indicate that the multiple cystic lesions of the placenta in this case are essentially different from those of a trophoblastic disease, and that the diffuse cystic lesion of the villi might have been secondary to changes in the local circulation.

Actins↗
PubMed1997

Adsorption of inhalational anesthetics and hydrochlorofluorocarbons on activated carbons as a biological model.

Chlorofluorocarbon (CFC) replacements have recently been used for their lower stability and because they have carbon-hydrogen bonds, which means that their atmospheric lifetime is expected to be much shorter than those of CFCs. The adsorption properties of 1,1,2-trichloro-1,2,2-trifluoroethane (CFC113) and its replacement compounds, 1,1-dichloro-2,2,2-trifluoroethane (HCFC123), 1,1-dichloro-1-fluoroethane (HCFC141b), and 1,1-dichloro-1,2,2,3,3-pentafluoropropane (HCFC255ca) on four kinds of activated carbons were investigated. The amount of CFC and HCFCs adsorbed on the activated carbon was concluded to depend upon the number of chloride and carbon atoms in their molecules. The adsorption isotherms of inhalational anesthetics (halothane, chloroform, enflurane, isoflurane, and methoxyflurane) on the activated carbon were measured to evaluate the action mechanism of inhalational anesthesia. The adsorption isotherms of CFC, HCFC, and the inhalational anesthetics were fitted to the Freundlich equation. The Freundlich constant N was well correlated with the minimum alveolar concentration (MAC) of the inhalational anesthetic: 1 MAC means that 50% of the patients will not move during a surgical operation. The adsorption mechanism of inhalational anesthetics on the surface of the activated carbon is concluded to be similar to the adsorption mechanism on a nerve cell. The anesthesia of CFC replacements can be estimated by the Freundlich constant N of the adsorption isotherms.

Adsorption↗
PubMed1997

[Study on the relationship between lifestyles and maximal oxygen uptake in healthy adults].

In this study, to determine the influence of different lifestyles on maximal oxygen uptake, we carried out a survey on the effects of age, smoking, physical exercise, clinical examination values and dietary habits of 899 male factory workers on their maximal oxygen uptake. The results of the study were as follows: Maximal oxygen uptake significantly decreased with age. In the male factory workers, there were significant correlations between maximal oxygen uptake and frequency of physical exercise, a greasy diet and seasoning of the diet. Multiple regression analysis showed that the variables which correlated best with the maximal oxygen uptake were serum total cholesterol and HDL cholesterol. These results indicated that good nutrition and physical activity are important for maintaining physical fitness.

Adult↗
PubMed1997

Relation between smoking and periodontal disease by oral hygiene status in Japanese factory workers.

The relation between smoking and periodontal disease as classified by the Community Periodontal Index of Treatment Needs (CPITN) code was investigated in 1,611 Japanese male factory workers in Osaka, 20-59 years of age. The Simplified Debris Index (DI-S) according to the Simplified Oral Hygiene Index was employed as an index for the quantity of dental plaque. For the items related to smoking, a self-reporting form on smoking, the number of years of smoking, and the number of cigarettes smoked was distributed prior to the oral examination. Our results indicated the following: in the group with a poor state of oral hygiene, the negative effects of smoking were evident, resulting in unhealthy periodontal tissue. We believe that this result further confirms the contention that the removal of dental plaque is most important as a prophylaxis for periodontal diseases, and public education about this negative consequence of smoking will further strengthen prophylactic measures.

Adult↗
PubMed1997

[Compton-scatter correction using the triple energy window (TEW) method in conventional single photon emission computed tomography without TEW acquisition hardware].

We devised a method which allowed the triple energy window (TEW) method to be applied for Compton-scatter correction in conventional single photon emission computed tomography (SPECT) systems without any hardware for TEW acquisition. In this method, the data within two subwindows located at both sides of the main window were acquired together. The effectiveness of this method was investigated by phantom experiments. The integral and differential uniformities measured using a flood phantom filled with 123I were minimized when the energy width of subwindows was 5 keV (5.8% and 4.2%, respectively). When this method was applied to a brain phantom filled with 123I in which the relative activities in white and gray matter were assigned as 1: 4.3, the ratio of SPECT values between them was more accurate (1:4.26) than that obtained without this method (1:208). This method appears to be useful for Compton-scatter correction in SPECT, because it can be applied to conventional SPECT systems without any hardware for TEW acquisition and is available for routine clinical use for its simplicity.

Brain↗
PubMed1996

Metastasizing uterine leiomyoma. A case with cardiac and pulmonary metastasis.

A case of histologically benign cardiac and pulmonary metastases from a uterine leiomyoma in a 45-year-old woman is reported. The solitary cardiac tumor consisted of five lobules with a stalk attached to the anterior papillary muscle of the right ventricle, which occupied the right ventricular cavity and almost completely obstructed the pulmonary main trunk in the systolic cycle. Multiple small nodules were found throughout both lungs. The cardiac tumor was resected at open heart surgery and open lung biopsy of the pulmonary lesion was simultaneously performed. Both of them were histologically identical to the apparently histologically benign uterine leiomyoma which had been resected five years previously. Based on the clinical and laboratory findings, it is postulated that antegrade metastases via the venous system resulted in the cardiac metastasis from the uterine leiomyoma and the secondary pulmonary metastasis from the cardiac tumor. In contrast to the light microscopic findings, ultrastructural examination suggested the possibility of malignancy associated with the presence of immature smooth muscle cells. This is the first reported case of a so-called benign metastasizing leiomyoma occurring in the heart.

Female↗
PubMed1996

A multicenter validation of regional cerebral blood flow quantitation using [123I]iodoamphetamine and single photon emission computed tomography.

Recently, two methods have been proposed for regional cerebral blood flow (rCBF) quantitation using [123I]iodoamphetamine (IMP) and single-photon emission computed tomography (SPECT). The table look-up (TLU) method has been shown to provide both rCBF and volume of distribution, Vd, images from two SPECT scans, while a single-scan autoradiographic (ARG) technique provided rCBF using a fixed and assumed Vd. In both methods, a single blood sample was referred to calibrate the previously determined standard input function. The present multicenter project was designed to evaluate the accuracy of both methods for use as clinical investigative tools. Ten independent institutions performed [123I]IMP-SPECT studies according to both methods in 76 subjects (10 normal volunteers, 32 patients with cerebrovascular disease, and 34 patients with other diseases). Calculated rCBF values were compared with those obtained by the following reference methods available in the participating institutions; [15O] H2O positron emission tomography (PET) (five institutions), [133Xe]SPECT (four institutions), and the [123I]IMP microsphere method (three institutions). Both ARG and TLU methods provided rCBF values that were significantly correlated with those measured by the [15O] H2O PET technique (p < 0.001 for all subjects; overall regression equation, y = 15.14 + 0.54x) and those measured by the [123I]IMP-microsphere method (p < 0.001 for all subjects: y = 2.0 + 0.80x). Significant correlation (p < 0.05) was observed in 18 of 24 subjects studied with the [133Xe] SPECT reference technique (overall regression equation, y = 15.0 + 0.55x). Mean cortical gray matter rCBF in a group of normal subject was 43.9 +/- 3.3 and 43.4 +/- 2.0 ml/min/100 g for the ARG and TLU methods, respectively. Regional Vd of [123I]IMP estimated by the TLU method was 45 ml/ml +/- 20% in the normal cortical region. Close agreement between ARG and TLU rCBF values was observed (y = -3.21 + 1.07x, r = 0.97), confirming the validity of assuming a fixed Vd in the ARG method. Results of this study demonstrate that both the ARG and TLU methods accurately and reliably estimate rCBF in a variety of clinical settings.

Adolescent↗
PubMed1996

Changes in cortical CBF and vascular response after vascular reconstruction in patients with adult onset moyamoya disease.

Using 133Xe single photon emission tomography, we evaluated the cortical region cerebral blood flow (rCBF) and vascular response to acetazolamide loading before and after vascular reconstructive surgery in 9 hemispheres in 6 patients with adult-onset moyamoya disease. Before the operation, the resting rCBF was not markedly impaired except that several low rCBF regions were present in the frontal and temporal lobes, and after the operation, the number of regions showing normal rCBF was significantly increased. Regional vascular response was more diffusely impaired in the regions with both normal and low rCBF before the operation, the excessively high response observed in the parietal and occipital lobes was well normalized after the operation, while the low response to acetazolamide challenge in the frontal and temporal lobes was not adequately improved.

Acetazolamide↗
PubMed1995

Thallium-201 myocardial tomography with intravenous infusion of adenosine triphosphate in diagnosis of coronary artery disease.

OBJECTIVES: The purpose of this study was to evaluate the feasibility, safety and diagnostic accuracy of thallium-201 myocardial tomography with intravenous adenosine triphosphate (ATP) infusion in patients with suspected coronary artery disease. BACKGROUND: Both ATP and adenosine are potent coronary vasodilators with a very short half-life. Several studies have confirmed that the diagnostic accuracy of adenosine thallium-201 scintigraphy is comparable to that with exercise. However, a high incidence of side effects, including atrioventricular (AV) block, has also been reported. Because the appropriate infusion rate for ATP has not yet been determined, this agent has not been tested in combination with myocardial scintigraphy. METHODS: The study group included 253 consecutive patients who underwent thallium-201 myocardial tomography with ATP infusion (0.16 mg/kg body weight per min for 5 min). The occurrence of adverse effects was carefully monitored. Of the 120 patients with coronary angiography, 76 had significant coronary artery disease. Tomographic images were assessed visually and by computer-quantified polar maps, and they were compared with the results of coronary angiography. RESULTS: Although 56% of the patients had some adverse effects, they were transient and mild. In all patients, the ATP infusion protocol could be completed, and no patient required aminophylline; AV block occurred in only 2% of the patients. The sensitivity and specificity were 88% and 80%, respectively, by visual analysis and 91% and 86%, respectively, by computer quantification. CONCLUSIONS: Thallium tomography with ATP is feasible and has a diagnostic value similar to that with adenosine for detecting coronary artery disease. In addition, it may have fewer side effects than adenosine myocardial tomography.

Adenosine Triphosphate↗
PubMed1995

[Experimental study on effects of a high-sugar diet and physical exercise on serum phospholipids in young adults].

The life style of young adults has been receiving attention with a view to its improvement to prevent coronary heart diseases (CHD) later in life. In this study, to determining the influence of different life styles on the serum phospholipids level, we carried out experimental studies on the effects a high sugar diet and physical exercise on serum phospholipid levels. Considering the trend for young people to consume large quantities of carbonated drinks, in which most of the sugar is sucrose, we tested the effect of a high carbohydrate diet on one group of six healthy male subjects and did not find that it caused a significant increase in the serum phospholipids level. In another group of 108 healthy young female subjects, a mild exercise regimen results in a slight, but significant decrease in the serum phospholipid level (p < 0.01). The serum total cholesterol level of the group did not exhibit a significant change.

Adult↗
PubMed1995

Evaluation of the effects of various factors on the serum alpha hydroxybutyrate dehydrogenase activity in young females.

In this study, for determining the influence of different life style on the serum alpha hydroxybutyrate dehydrogenase activity (alpha HBD), we carried out surveys and laboratory studies on the relationships of the nutritional intake, physical activity, cigarette smoking and alcohol consumption of young females with their serum alpha HBD activity. There are significant positive correlation between alpha HBD and GOT, GPT, LDH, CPK, phospholipids, total cholesterol, and HDL-cholesterol, and significant negative correlation between alpha HBD/LDH and GOT, GPT, and gamma GTP. There are significant positive or negative correlation between alpha HBD and systolic pressure, diastolic pressure, cardiac index, stoke volume and total periperal resistance, and significant negative correlation between alpha HBD/LDH and vital capacity in young females. The serum alpha HBD activity levels of nonsmokers was significant higher than those of smokers (p < 0.05). There are significant positive correlations between serum alpha HBD activity and beverage consumption, and between alpha HBD/LDH and protein, calcium, vitamin A, B1, B2, C, pulses, vegetables and milk in young females. The finding shows that the group of serum alpha HBD activity level of 240 or more units exhibited higher level of rate of those who exercised sometimes+usually than the other group in young females. However, the serum alpha HBD activity level did not show significant correlation with energy expenditures per day. Exercise at 50 and 70% VO2 max may produce a significant increase in their serum alpha HBD activity. There is a possibility that serum alpha HBD activity may serve as an indicator for ones health condition. It is undeniable that observation of variation of serum alpha HBD activity is highly significant in health maintenance.

Activities of Daily Living↗