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OBJECTIVE: The purpose of this study was to characterize the etching behavior of titanium in concentrated sulfuric acid and discuss its application on surface modification of titanium for biological use. METHODS: Commercially pure titanium (cpTi) plate was etched in 48% H2SO4 at RT -90 degrees C for 0.25-8 h. The weight loss was derived from the weight differences before and after etching. The surfaces after etching were characterized by surface roughness, X-ray diffractometry, and scannning electron spectroscopy. The apparent activation energy of the dissolution of cpTi into acid was derived from an Arrhenius plot of the rate of weight loss versus the acid temperature. RESULTS: The surface roughness of cpTi increased with the acid temperature and etching time. The surface roughness was strongly related to the weight loss. The weight loss increased drastically with the acid temperature after an initial period, which shortened with increasing acid temperature. The apparent activation energy for the dissolution of cpTi in H2SO4 was derived as 67.8 kJ/mol. SIGNIFICANCE: This study indicates that etching with concentrated sulfuric acid is an effective way to modify the surface of titanium for biological applications. 相似文献
3.
紫杉醇和维甲酸对前列腺癌PC-3细胞的作用 总被引:1,自引:0,他引:1
目的 观察紫杉醇 (PA)和维甲酸 (RA)协同对前列腺癌细胞系PC 3的体外作用 ,并探讨其可能的作用机制。方法 应用光镜形态学、噻唑蓝 (MTT)法、流式细胞仪和免疫细胞化学法观察了 10 -6、10 -7、10 -8mol/L浓度紫杉醇和 10 -5、10 -6、10 -7mol/L浓度维甲酸在体外单药或协同对前列腺癌细胞系PC 3的作用和对细胞DNA含量及CyclinD1表达的影响。 结果 10 -6mol/L以上浓度维甲酸作用 48h可增强 10 -7mol/L以上浓度紫杉醇对前列腺癌PC 3细胞系的生长抑制 [抑制率≥ (5 6.3± 5 .2 ) % ,P <0 .0 5 ] ,增强诱导凋亡作用 [凋亡率≥ (2 0 .5± 2 .3 ) % ,P <0 .0 5 ] ,下调CyclinD1的表达 [表达率≤ (9.2± 1.1) % ]。维甲酸使紫杉醇所致的G2 /M期细胞比例由 (70 .3± 9.3 ) %变为 (5 4.6± 6.7) % ,部分地逆转了其G2 /M期细胞周期阻滞 (P <0 .0 5 )。结论 紫杉醇和维甲酸可以协同增强对前列腺癌细胞系PC 3的生长抑制和诱导凋亡作用 ,显示了紫杉醇和维甲酸协同用于治疗激素非依赖性前列腺癌的可能性。 相似文献
4.
目的:观察高渗氯化钠高氧液对失血性休克家兔动脉血气和血乳酸值的影响,评价其对失血性休克的早期救治效果。方法:制备高渗氯化钠溶液(HS)、生理盐水高氧液(NSO)和高渗氯化钠高氧液(HSO)。30只雄性家兔制备失血性休克模型[于10min内使平均动脉压(MAP)降至40mmHg(1mmHg=0.133kPa),维持60min],随机分为NSO,HS,HSO组3个治疗组。分别按6mL/kg剂量5min内静脉输入NSO,HS和HSO。记录休克前后及给药后心率(HR)、呼吸(RR)、MAP及尿滴(UD),测定休克前、休克60min,给药后30,60,120min时血乳酸(BL)和动脉血气值。最后观察尸肺,测定肺系数。结果:HS和HSO组均显著地改善MAP,HR和UD,降低BL,改善代谢性酸中毒,肺系数明显低于NSO组。HSO与NSO及HS比较,能更显著地降低血BL,提高动脉血氧饱和度(SaO2)和动脉血氧分压(PaO2)。结论:HSO较HS和NSO能更显著地降低血BL,提高SaO2和PaO2,对失血性休克的早期救治具有较高的使用价值。 相似文献
5.
Cultured human proximal tubule cell monolayers maintained on permeable supports were treated simultaneously with the aminoglycoside antibiotic, gentamicin, and poly-
-aspartic acid (PAA), an inhibitor of aminoglycoside nephrotoxicity. Following 4 days of exposure, cell monolayers were placed into Ussing chambers to allow monitoring of transepithelial electrical properties. For each of the three cell isolatation examined, aminoglycoside-induced alterations in electrogenic transport, reflected by changes in short-circuit current (Isc), as well as alterations in paracellular properties, indicated by changes in transepithelial electrical resistance (RT), were diminished in the presence of PAA. Alterations resulting from selective basolateral exposure to gentamicin were unchanged in the case of apically applied PAA and attenuated only when PAA acid was added basolaterally. This is the first demonstration of PAA inhibition of aminoglycoside-induced cellular alterations involving human cells. 相似文献
6.
健脾降脂颗粒中绿原酸的含量测定 总被引:1,自引:0,他引:1
目的 研究健脾降脂颗粒中绿原酸的含量测定方法。方法 采用高效液相法。色谱柱YWGC18(2 5 0mm× 4 6mm ,10 μm) ,室温 ,10 %乙腈─冰醋酸 (5∶0 1)为流动相 ,流速为 1mL/min ,检测波长 32 9nm。结果 绿原酸在 0 0 2 0 8~ 0 10 4 μg范围内呈线性关系 (r =0 9994 ,n =5 ) ,平均加样回收率为 96 2 3% ,RSD为 0 798%。结论 本方法准确、可行 ,可用于健脾降脂颗粒的质量控制 相似文献
7.
Mirna SuČIĆ Dubravka Boban Mirjana MarkoviĆ-glamoČak Mladen PetroveČki Matko MaruŠIĆ Boris Labar 《Medical oncology (Northwood, London, England)》1992,9(1):41-45
Cytochemical analysis of leukemic blasts from 46 patients with acute myeloblastic M2 leukemia (according to the FAB classification)
was performed before and after cytostatic therapy, and compared with findings obtained in 20 age- and sex-matched control
subjects. Cytochemical findings for myeloperoxidase (MPO), Sudan black B, acid phosphatase and alpha-naphthyl-acetate esterase
(ANAE) were related to the achievement of the first complete remission (CR),i.e. data were compared after the patients had been divided into CR and non-CR groups. The analysis clearly showed that a high
proportion of myeloperoxidase- and, to a lesser extent, Sudan black B-positive blasts before treatment may have constituted
a significantly unfavourable prognostic factor. 相似文献
8.
Amanda M. Cockshutt Laurent Jonet Jean-Claude Jeanny Marc Vigny Dr. Daniel Raulais 《Developmental dynamics》1994,200(3):198-211
Retinoic acid induced heparin-binding protein (RIHB) is a highly basic, soluble polypeptide of the chick embryonic extracellular matrix. We have examined the expression and localization of RIHB during very early embryogenesis by in situ hybridization and immunohistochemistry. RIHB mRNA is very weakly detectable above background in the blastodiscs of unincubated eggs. The expression increases greatly over the first 24 hours of incubation, and is observed throughout the blastodisc in all three of the germ layers following gastrulation. As neurulation occurs, the expression becomes more restricted to certain areas, notably the ectoderm, the neural folds, and especially the notochord. After the neural tube has formed the expression in the tube itself decreases dramatically, whereas the expression in the head ectoderm and the notochord persists. After 72 hours of incubation expression remains relatively high throughout most of the embryo, with higher levels of expression in regions undergoing organogenesis and lower levels in organs which have already differentiated. RIHB protein is also weakly detectable in unincubated eggs as patches of immunoreactive material between the blastodisc and the vitelline. After 6 hours of incubation small regions of basement membrane are immunoreactive. RIHB is detected in this matrix, apparently before even fibronectin. The amount of RIHB protein increases dramatically over the first 24 hours of incubation. It is found in basement membrane separating the epiblast from the hypoblast, then later in that separating the ectoderm from the mesoderm. It is also detected surrounding individual cells, especially of the ectodermal layer. During neurulation RIHB is observed in the basement membrane surrounding the neural fold and the notochord, and in the lamina separating the ectodermal, mesodermal, and endodermal layers. Later in development, RIHB is detected in the basement membrane under the epidermis, throughout the developing limbs, and in the lamina of various developing organs, such as the eye, the pulmonary bud, the intestine, and the mesonephros. These results demonstrate that RIHB is highly expressed during the early embryonic period, by all three germ layers, and is an important and very early component of the embryonic extracellular matrix. Its very broad expression and localization argue for a more general role in development than its demonstrated weak neurotrophic activity. © 1994 Wiley-Liss, Inc. 相似文献
9.
Effect of surface conditioning methods on the bond strength of luting cement to ceramics 总被引:9,自引:0,他引:9
OBJECTIVES: This study evaluated the effect of three different surface conditioning methods on the bond strength of a Bis-GMA based luting cement to six commercial dental ceramics. METHODS: Six disc shaped ceramic specimens (glass ceramics, glass infiltrated alumina, glass infiltrated zirconium dioxide reinforced alumina) were used for each test group yielding a total number of 216 specimens. The specimens in each group were randomly assigned to one of the each following treatment conditions: (1) hydrofluoric acid etching, (2) airborne particle abrasion, (3) tribochemical silica coating. The resin composite luting cement was bonded to the conditioned and silanized ceramics using polyethylene molds. All specimens were tested at dry and thermocycled (6.000, 5-55 degrees C, 30 s) conditions. The shear bond strength of luting cement to ceramics was measured in a universal testing machine (1 mm/min). RESULTS: In dry conditions, acid etched glass ceramics exhibited significantly higher results (26.4-29.4 MPa) than those of glass infiltrated alumina ceramics (5.3-18.1 MPa) or zirconium dioxide (8.1 MPa) (ANOVA, P<0.001). Silica coating with silanization increased the bond strength significantly for high-alumina ceramics (8.5-21.8 MPa) and glass infiltrated zirconium dioxide ceramic (17.4 MPa) compared to that of airborne particle abrasion (ANOVA, P<0.001). Thermocycling decreased the bond strengths significantly after all of the conditioning methods tested. SIGNIFICANCE: Bond strengths of the luting cement tested on the dental ceramics following surface conditioning methods varied in accordance with the ceramic types. Hydrofluoric acid gel was effective mostly on the ceramics having glassy matrix in their structures. Roughening the ceramic surfaces with air particle abrasion provided higher bond strengths for high-alumina ceramics and the values increased more significantly after silica coating/silanization. 相似文献
10.
CYP2A6基因多态性对丙戊酸钠血药浓度的影响 总被引:5,自引:0,他引:5
目的探讨细胞色素P4502A6(CYP2A6)基因多态性对丙戊酸钠血药浓度的影响。方法选择单药服用丙戊酸钠的癫患者98例,应用巢式PCR(nested-primerpolymerasechainreaction)方法分析其CYP2A6基因型,分析等位基因CYP2A6*1及CYP2A6*4;同时应用荧光偏振免疫法(FPIA)测定患者丙戊酸钠的血药浓度。结果98例患者中CYP2A6基因型为*1/*1者73例(74·5%),*1/*4者24例(24·5%),*4/*4者1例(1·0%),根据基因型分为A组(CYP2A6*1/*1)和B组(CYP2A6*1/*4或CYP2A6*4/*4)。B组患者丙戊酸钠的标准血药浓度平均值(4·1393±0·2793)较A组(3·3486±0·3919)高,差异有统计学意义(P<0·05)。结论CYP2A6基因多态性影响丙戊酸钠的血药浓度,含有CYP2A6*4等位基因的患者应用丙戊酸钠应较常规降低用量。 相似文献