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排序方式: 共有610条查询结果,搜索用时 15 毫秒
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M Sato A Kondo S Otsuka H Tanabe N Matsuura K Hasegawa M Chin M Saiki 《Canadian Metallurgical Quarterly》1993,21(12):1143-1147
The authors report a rare case of a large cystic cervical neurinoma. A 45-year-old female was admitted to our clinic because of motor weakness of the right upper extremity, numbness of the right fingers and right posterior cervical pain. Metrizamide CT myelography demonstrated the outline of a low density mass. MRI showed a mass revealing low signal intensity on T1-weighted image, high signal intensity on T2-weighted image and marginal enhancement on contrast image with Gd-DTPA. The mass which was diagnosed as cystic tumor, was located in the intradural extramedullary space between C4 to C5 segments. After C4 through C5 laminectomy, the tumor was found to originate from the C5 anterior motor root. The tumor consisted mostly of a cystic part with a very thin solid compartment beneath the capsule. Postoperative course of the patient was uneventful. Although spinal neurinoma is one of the most common spinal tumors, an almost completely degenerated large cystic spinal neurinoma is extremely rare. MRI with Gd-DTPA was useful for the diagnosis of the cystic neurinoma by clearly enhancing the margin of the tumor. 相似文献
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M Otsuka Y Ichiya Y Kuwabara M Sasaki T Yoshida T Fukumura K Masuda 《Canadian Metallurgical Quarterly》1995,16(12):1021-1025
The existence of the nigrofrontal dopaminergic pathway has been demonstrated in neuroanatomical studies. We evaluated the presynaptic nigrofrontal dopaminergic function using 18F-dopa (FD) positron emission tomography (PET). The multiple time PET data in the frontal cortex from 20 to 70 min post-injection for FD were evaluated by Patlak analysis using the cerebellar time-activity curve as an input function. The frontal FD uptake rate constants could not be determined in 5 of 12 normal volunteers because of large deviations in the plots. There were no significant differences between the subjects among whom the frontal FD uptake rate constants could or could not be determined regarding the amount of FD injected, the frontal 18F counts, or whether or not they were pretreated with carbidopa. The uptake constants were determined in 9 or 12 patients with parkinsonian syndrome. While the mean (+/- S.D.) uptake constants in patients with Parkinson's disease (2.89 +/- 0.06 x 10(-3), n = 4) and in patients with progressive supranuclear palsy (2.81 +/- 0.10 x 10(-3), n = 3) were not significantly different from those in the normal volunteers (2.93 +/- 0.14 x 10(-3)), those in two patients with corticobasal degeneration (2.42 and 2.46, respectively) decreased in comparison to the control values. Differences in the nigrofrontal presynaptic dopaminergic function as assessed by FD-PET may explain the different pathogenesis and also help to differentiate between corticobasal degeneration and other parkinsonian syndromes, such as Parkinson's disease and progressive supranuclear palsy. 相似文献
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Makoto Otsuka 《Drug development and industrial pharmacy》1993,19(17):2241-2269
The effects of temperature on the polymorphic transformation and the compression of chlorpropamlde forms A and C during tabletting were investigated by X-ray diffractometry. The X-ray diffraction profiles of the sample powders deagglomerated after compression were recorded to calculate the degree of polymorphic transformation. A single punch eccentric tabletting machine equipped with two load cells (upper and lower punches) and with a noncontact displacement transducer was used to measure the compression stress, energy and distance between punches. A heater and a liquid nitrogen pool were mounted on the die of the tabletting machine, and the die temperature was controlled with a thermocontroller. Two types of compression methods, multi-tabletting at room temperature and single tabletting at 0-45°C, were used in the present study. In the first method, the stable form A or metastable form C was loaded in to the die and the sample was compressed with a compression stress of 196 MPa. Compression was repeated from 1 to 30 times. The results for forms A and C suggested that both forms were mutually transformed, and that the content of forms A and C reached equilibrium above 100 J/g of compression energy after more than 10-times compression. After 30-times compression, the content of A, C, and the noncrystalline solid form were almost constant at about 45%, 25% and 30%, respectively. The compression energy was estimated to be 500-600 J/g. In the second method, single tabletting at 0° and 45°C, the amount of form C transformed from form A at 45°C was about two times larger than that at 0°C at the same compression energy. The amount of form A transformed from form C at 45°C was almost the same as that transformed at 0°C. This suggests that the mechanochemical stability of form A was affected by compression temperature, while that of form C was independent of temperature. The crushing strength (CS) of from A tablet was about two times higher than that of form C even at the same porosity. The relationships between log (CS) of form A tablets compressed at 0 or 45°C and porosity showed straight lines with the same slope, but the slope for form C tablets compressed at 45°C was smaller than that for those compression at 0°C. From these results it appears that the transformation mechanism of forms A and C during compression was as follows: Form A or C was converted to a noncrystalline solid by mechanical energy, and then the solid was transformed into form A or C. The transformation of every form was affected by the environmental temperature. 相似文献
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Toshihide Suzuki Teruo Miyazawa Kenshiro Fujimoto Miki Otsuka Masako Tsutsumi 《Lipids》1993,28(8):775-778
The levels of phosphatidylcholine hydroperoxide in serially cultured human fetal diploid fibroblasts at various population
doubling levels were determined by high-performance liquid chromatography combined with chemiluminescence detections. This
methodology utilizes a mixture of cytochromec and luminol as post-column hydroperoxide group specific luminescent reagents. The cellular hydroperoxide content increased
with age from 0.34 to 27.72 pmol/106 cells. At the end of the cells'in vitro lifespan (51st population doubling level), the hydroperoxide content per 106 cells reached about 80 times the level found in cells of the 20th population doubling level. Supplementation of exogenous
α-tocopherol to the culture medium prevented hydroperoxide accumulation, but did not extent the lifespanin vitro. The results indicate that substantial intracellular phospholipid hydroperoxide accumulation occurred in the course of aging
of human fetal liploid fibroblasts. 相似文献
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The stepwise insertion reaction of styrene (St) and p-tert-butoxystyrene (BOSt) into poly(alkoxyamine) macroinitiator was carried out to provide well-defined poly(St)-b-poly(BOSt) multiblock copolymers. Structural confirmation of the multiblock copolymers was accomplished by NMR and IR measurements. The model reaction also supported that the monomer insertion into the macroinitiator proceeded in accordance with a living fashion. 相似文献
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N,O,O′─三(对甲苯磺酰基)双(2─羟乙基)胺的合成 总被引:1,自引:0,他引:1
二乙醇胺和对甲苯磺酰氯在三乙胺存在下,反应生成N,0,O′-三(对甲苯磺酰基)双(2-羟乙基)胺,产率93%。从反应混合物中分离得副产物N,O-二(对甲苯磺酰基)双(2-羟乙基)胺。 相似文献