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排序方式: 共有597条查询结果,搜索用时 15 毫秒
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Hysterosalpingography was performed in 31 patients by means of a low-dose scanning-beam digital radiographic system. The technique permits adequate evaluation of gynecologic abnormalities while allowing significant reduction in radiation: 2.4-mR (6.1 X 10(-7) C/kg) exposure to the skin and 0.7-mrad (7 X 10(-6) Gy) mean dose to the ovaries per image obtained. Sixteen patients demonstrated readily recognizable and documented abnormalities, corroborated by laparoscopy, laparotomy, or other supportive evidence. 相似文献
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The broad background of scattered light observed in spectra of cell suspensions is reduced by factors of up to 20 by immersion refractometry allowing for improved spectroscopic determination of the absorption properties of cells in the 325-820 nm range. Refractive-index matched spectra of E. coli C1a exhibit a set of resonant features near 422, 561, and 582 nm. Exposure wavelengths are chosen based on this spectrum and cell viability is investigated in E. coli suspensions exposed to 350, 400, 422, 440, and 700 nm radiation delivered in nanosecond pulses with total doses from 500 millijoules to 60 Joules. We observe a loss in cell viability for doses greater than 1 Joule at 422 nm and for all doses at other wavelengths; exposures of less than 1 Joule at 422 nm enhance growth. Excluding exposures at wavelengths within the resonant feature, longer wavelengths are less effective at reducing the viability of E. coli C1a. This indicates the occurrence of at least two absorption processes. 相似文献
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M Korff S W Bent M T Havig M K Schwaber R H Ossoff D L Zealear 《Otolaryngology--head and neck surgery》1992,106(4):345-350
Suture repair of a severed peripheral nerve is cumbersome, presents a focus for infection and neuroma formation, and does not always produce adequate stump alignment. An alternative form of repair is laser nerve welding, which is attractive because it does not introduce foreign material into the anastomotic site, it forms a circumferential seal, and it can be performed in difficult-to-reach areas. Laser repair has not been widely accepted both because the effect of laser irradiation on intact nerves is not well documented, and the anastomotic strength of the weld has been inferior to suture repair. In the first part of the present study, rat sciatic nerves were exposed and irradiated with increasing intensities from a Sharplan CO2 and KTP laser to document nerve damage as recorded by decreases in the peak compound action potential. A new technique of laser repair (S-Q weld) was then developed that involved harvesting subcutaneous tissue from the adjacent dermis, wrapping it around the two opposed nerve stumps, and lasering it to the epineurium to effect a weld. The strength of the S-Q weld (6.1 grams) was considerably greater than that produced by laser welding alone. The third phase of the study compared regeneration at 2 months in severed rat sciatic nerves repaired by either microsuture or S-Q weld. Analysis of the compound action potential values indicated that the number of regenerating fibers after laser repair was greater than that after suture repair, although a significant difference could not be demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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Noninvasive metabolic magnetic resonance (MR) imaging reflecting glucose metabolism in the aldose-reductase-sorbitol (ARS) pathway was performed in the rabbit head; after administration of the fluorinated glucose analogue 3-fluoro-3-deoxy-D-glucose (3FD-glucose), fluorine-19 images were generated. Images of 3FD-glucose showed significant 3FD-glucose uptake by adipose tissue, indicating its buffering effects in case of excess loads of glucose. Images of 3-fluoro-3-deoxy-D-sorbitol (3FD-sorbitol) demonstrated the spatial distribution of aldose reductase activities and significant sorbitol accumulation in the lens. Images of 3-fluoro-3-deoxy-D-fructose (3FD-fructose) showed preferential uptake of fructose by muscle tissue. The extremely low toxicity of 3FD-glucose indicates promise for its clinical application in metabolic imaging. 相似文献
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目的:血小板衍生生长因子在平滑肌细胞的表型转化过程中起重要作用。观察大鼠移植心脏组织中血小板衍生生长因子AmRNA表达的变化及雷帕霉素的干预效应。方法:实验于2005-10/2006-01在中南大学湘雅二医院胸心外科实验室完成。将60只SD大鼠、24只Wistar大鼠按随机数字表法分为3组:①同系移植组:供、受体各12只,均为SD大鼠。②异系移植组:供体为Wistar大鼠(n=24),受体为SD大鼠(n=24),受体大鼠随机分为雷帕霉素组(n=12)和环孢霉素组(n=12),术后分别给予雷帕霉素1.25mg/(kg·d)灌胃及环孢霉素A10mg/(kg·d)皮下注射,给药60d,给药结束后留取移植心脏待检。③另12只SD大鼠直接取心脏组织作为正常对照组。指标检测:①对移植心脏组织行VanGieson染色后采用Miassystem4.1医学图像分析管理系统分析血管狭窄程度。②应用反转录-聚合酶链反应检测血小板衍生生长因子AmRNA在移植心脏组织中的表达情况。结果:36只受体SD大鼠及12只正常SD大鼠全部进入结果分析,无脱失。①同系移植组、环孢霉素组及雷帕霉素组大鼠的冠状动脉狭窄指数均显著高于正常对照组[(13.12±0.72)%,(62.45±8.12)%,(28.91±3.24)%,(0.09±0.02)%(P<0.01)],环孢霉素组及雷帕霉素组高于同系移植组(P<0.05),环孢霉素组高于雷帕霉素组(P<0.01)。②正常对照组、同系移植组、环孢霉素组及雷帕霉素组大鼠的血小板衍生生长因子AmRNA相对含量分别为0.19±0.06,0.21±0.08,1.12±0.22及0.47±0.11,环孢霉素组、雷帕霉素组显著高于同系移植组(P<0.01),环孢霉素组高于雷帕霉素组(P<0.05)。结论:血小板衍生生长因子AmRNA的高表达与移植心脏的血管硬化有关;雷帕霉素具有预防大鼠心脏移植物血管病变的作用,其作用可能与抑制心脏组织中血小板衍生生长因子AmRNA的表达有关。 相似文献
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