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排序方式: 共有1510条查询结果,搜索用时 15 毫秒
1.
目的 观察奥美定注入小香猪体内后的生殖毒性。方法 注入奥美定后观察小香猪母代及子代的生长、健康情况 ,抽出奥美定检测丙烯酰胺单体含量以及抽血查染色体及微核试验观察。结果 6只母代小香猪健康 ,2只与公猪交配 ,4个月及 5个月后生出 9只及 4只子代小猪 ,健康情况亦良好。在半年及 1年后分别抽出奥美定检测丙烯酰胺单体没有增加 ,共检测 9只小香猪的染色体包括母代及子代 ,均未发现数目畸变及结构畸变 ,微核试验有细微的变化 ,并初步反映出与用药量大小呈正相关 ,但超量注射的一只动物 (18.5ml/kg)变化的千分值仍在正常范围内。结论 从目前几项观察与检测指标看 ,实验量奥美定注入小香猪体内尚不具生殖遗传毒性 相似文献
2.
A controlled, double-masked, randomized study was conducted on ten subjects to determine the effect of fenestration size on the initial comfort of hydrogel contact lenses. Four fenestrated lenses were tested, each lens containing four mid-peripheral fenestrations of the same size. The diameter of the fenestrations used in the four lenses ranged from 0.39 to 0.96 mm. An unfenestrated lens was also tested. All lenses were made of HEMA and were ordered with the following specifications: -3.00 D, 14.0 mm diameter, 8.4 mm back central optic radius and 0.06 mm centre thickness. There was a significant negative correlation between comfort and fenestration size, indicating that larger fenestrations are less comfortable. Even the lens with the smallest fenestrations (0.39 mm) was significantly less comfortable than the unfenestrated lens. The implication of this finding is that fenestrations may not be clinically efficacious in view of the poor comfort (and presumably increased mechanical effect of the fenestration edges on the tarsal conjunctiva) of fenestrated lenses. 相似文献
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4.
E. Waris M. Pakkanen K. Lassila P. Törmälä Y. T. Konttinen R. Suuronen N. Ashammakhi 《European journal of plastic surgery》2003,26(7):350-355
A wide variety of biological and alloplastic injectable biomaterials are available for soft tissue augmentation, but the ideal material has not yet been discovered. Biological materials such as collagen and hyaluronan yield temporary results, while injectable alloplasts are apt to cause varying degrees of foreign body reactions that may result in lumps and chronic inflammation.We present two cases (one is the first filed case in the world) of migratory subcutaneous inflammatory masses secondary to injection of acrylic hydrogel (DermaLive), which is an alloplastic biomaterial recently introduced into the market in Europe. Histology revealed foreign body reaction to acrylic hydrogel with granuloma formation containing multinucleated giant cells. Following this, further reports on complications have been reported elsewhere in Europe. The use and development of injectable materials, as well as alternative methods and future directions are reviewed. 相似文献
5.
Millicent Ford Rauch Sara Royce Hynes James Bertram y Redmond Rebecca Robinson Cicely Williams Hao Xu Joseph A. Madri Erin B. Lavik 《The European journal of neuroscience》2009,29(1):132-145
Angiogenesis precedes recovery following spinal cord injury and its extent correlates with neural regeneration, suggesting that angiogenesis may play a role in repair. An important precondition for studying the role of angiogenesis is the ability to induce it in a controlled manner. Previously, we showed that a coculture of endothelial cells (ECs) and neural progenitor cells (NPCs) promoted the formation of stable tubes in vitro and stable, functional vascular networks in vivo in a subcutaneous model. We sought to test whether a similar coculture would lead to the formation of stable functional vessels in the spinal cord following injury. We created microvascular networks in a biodegradable two-component implant system and tested the ability of the coculture or controls (lesion control, implant alone, implant + ECs or implant + NPCs) to promote angiogenesis in a rat hemisection model of spinal cord injury. The coculture implant led to a fourfold increase in functional vessels compared with the lesion control, implant alone or implant + NPCs groups and a twofold increase in functional vessels over the implant + ECs group. Furthermore, half of the vessels in the coculture implant exhibited positive staining for the endothelial barrier antigen, a marker for the formation of the blood–spinal cord barrier. No other groups have shown positive staining for the blood–spinal cord barrier in the injury epicenter. This work provides a novel method to induce angiogenesis following spinal cord injury and a foundation for studying its role in repair. 相似文献
6.
Won-Gun Koh Alexander Revzin Aleksandr Simonian Tony Reeves Michael Pishko 《Biomedical microdevices》2003,5(1):11-19
A simple method for controlling the spatial positioning of mammalian cells and bacteria on substrates using patterned poly(ethylene glycol) (PEG) hydrogel microstructures is described. These microstructures were fabricated using photolithography on silicon, glass or poly (dimethylsiloxane) (PDMS) surfaces modified with a 3-(trichlorosilyl) propyl methacrylate (TPM) monolayer. During the photogelation reaction, the resulting hydrogel microstructures were covalently bound to the substrate via the TPM monolayer and did not detached from the substrate upon hydration. For mammalian cell patterning, microwell arrays of different dimensions were fabricated. These microwells were composed of hydrophilic PEG hydrogel walls surrounding hydrophobic TPM floors inside the microwells. Murine 3T3 fibroblasts and transformed hepatocytes were shown to selectively adhere to the TPM monolayer inside the microwells, maintaining their viability, while adherent cells were not present on the hydrogel walls. The number of cells inside one microwell could be controled by changing the lateral dimension of the microwells, thus allowing only a single cell per microwell if desired. In the case of 30×30 m microwells, as many as 400 microwells were fabricated in 1 mm2. In addition, PEG hydrogel microstructures were also shown to effectively resist the adhesion of bacteria such as Escherichia coli. 相似文献
7.
Novel pH-sensitive hydrogels were developed as suitable candidates for carriers in bioMEMS devices as well as for oral delivery of therapeutic peptides and proteins due to their ability to respond to environmental pH change. Macromonomers containing various PEG molecular weights were synthesized and used to prepare P(MAA-g-EG) hydrogels were by photopolymerization. P(MAA-g-EG) hydrogels showed a drastic change of the equilibrium swelling ratio between pH 2.2 and 7.0. At pH 7.0, hydrogels with PEGMA2000 exhibited higher swelling ratio than hydrogels with PEGMA1000. For both hydrogels with PEGMA1000 and PEGMA2000, the swelling mechanism became more relaxation-controled as the environmental pH changed from 2.2 to 7.0 due to the ionization of the functional groups in polymer networks at high pH. In vitro release studies of insulin were conducted. P(MAA-g-EG) hydrogels exhibited drastic increase of insulin release as the pH of the medium was changed from acidic to basic. Insulin release from P(MAA-g-EG) hydrogels with PEGMA2000 was slower than from hydrogels with PEGMA1000 at both low and high pH. These results were used to design and improve protein release behavior from these carriers. 相似文献
8.
Daniel Hork Franti eksvec Jaroslav Klal Arnold A. Adamyan Yurii D. Volynskii Olga S. Voronkova Leonid S. Kokov Klara Z. Gumargalieva 《Biomaterials》1986,7(6):467-470
In this study we report the results of clinical experiments, obtained with spherical particles made from poly(2-hydroxyethyl methacrylate) used in the embolization of arteriovenous anastomoses, in the suppression of pulmonary haemorrhage and haemoptysis and in the occlusion of some other arteries. So far we have used these particles in the treatment of 187 patients. It must be stressed that the advantage of spherical particles consists in the simplicity of their introduction into the blood vessel through a catheter, while in the blood vessel itself the particle swells in blood still more, when compared with the particle size in saline. This results in an immediate and permanent haemostatic effect. No revascularization occurs. 相似文献
9.
Masayuki Ishihara PhD Kiyohaya Obara MD Singo Nakamura PhD Masanori Fujita MD PhD Kazunori Masuoka MD Yasuhiro Kanatani MD PhD Bonpei Takase MD PhD Hidemi Hattori PhD Yuji Morimoto MD PhD Miya Ishihara PhD Tadaaki Maehara MD PhD Makoto Kikuchi PhD 《Journal of artificial organs》2006,9(1):8-16
An aqueous solution of photocrosslinkable chitosan containing azide groups and lactose moieties (Az-CH-LA) incorporating paclitaxel
formed an insoluble hydrogel within 30 s of ultraviolet light (UV) irradiation. The chitosan hydrogel showed strong potential
for use as a new tissue adhesive in surgical applications and wound dressing. The fibroblast growth factor (FGF)-2 molecules
retained in the chitosan hydrogel and in an injectable chitosan/IO4-heparin hydrogel remain biologically active, and were gradually released from the hydrogels as they biodegraded in vivo.
The controlled release of biologically active FGF-2 molecules from the hydrogels caused induction of angiogenesis and collateral
circulation occurred in healing-impaired diabetic (db/db) mice and in the ischemic limbs of rats. Paclitaxel, which is an antitumor reagent, was also retained in the chitosan hydrogel
and remained biologically active as it was released on degradation of the hydrogel in vivo. The chitosan hydrogels incorporating
paclitaxel effectively inhibited tumor growth and angiogenesis in mice. The purpose of this review is to describe the effectiveness
of chitosan hydrogel as a local drug delivery carrier for agents (e.g., FGF-2 and paclitaxel) to control angiogenesis. It
is thus proposed that chitosan hydrogel may be a promising new local carrier for drugs such as FGF-2 and paclitaxel to control
vascularization. 相似文献
10.
目的评估人工髓核材料聚乙烯醇水凝胶/聚乙烯纤维复合物的生物相容性。方法根据ISO10993-1标准,采用细胞毒性试验(琼脂扩散法)、皮内刺激试验、Ame's致突变试验、微核试验和体内植入(360天)试验对聚乙烯醇水凝胶/聚乙烯纤维复合物的生物相容性进行评估。结果聚乙烯醇水凝胶/聚乙烯纤维复合物的细胞毒性评分小于Ⅰ级,细胞生长无明显抑制现象,对皮内无刺激作用,Ames致突变试验为阴性,微核出现率为3.48‰,无致突变反应。体内植入符合植入材料生物学评价要求。结论聚乙烯醇水凝胶/聚乙烯纤维复合物具有良好的生物安全性,是一种无毒、对皮肤及肌肉、椎间隙无刺激作用的生物医用材料,在动物体内不引起排异反应,可应用于临床。 相似文献