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31.
P Ducheyne 《Biomaterials》1983,4(3):185-191
As a first part of a biocompatibility testing programme, in vitro corrosion tests were carried out on porous stainless steel AISI 316L and titanium compacts made of 100 microns thick fibres. The present porous metal structures are used as coatings on permanent orthopaedic implants; with osseous tissue invading the pores, the implant becomes securely anchored to the surrounding bone. The results show that no inadvertent reactions occur with porous titanium. It can probably be used with no greater risk of localized electrochemical attack than the parent bulk material. 相似文献
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33.
多种金属离子与单宁酸反应媒染微血管的对比研究 总被引:2,自引:0,他引:2
目的 镜下观察单宁酸与金属盐溶液中Ca2 + 、Au+ 、Ag+ 、Pb2 + 、Cu2 + 、Al3 + 、U6+ 、K+ 联用显示大脑微血管的效果。方法 用单宁酸媒染固定液灌流大鼠 ,取脑切片 ,入氯化钙、氯化金、硝酸银、硝酸铅、硫酸铜、硫酸铝钾、醋酸双氧铀、高锰酸钾和重铬酸钾等溶液中呈色。结果 单宁酸与Ca2 + 、Cu2 + 、Ag+ 、Al3 + 结合显示血管清晰 ,与Au+ 、U6+ 、Pb2 + 、K+ 联用媒染血管效果欠佳。结论 含Ca2 + 、Cu2 + 、Ag+ 、Al3 + 的金属盐类可替代氯化铁媒染微血管 ,氯化金、醋酸双氧铀、硝酸铅、重铬酸钾和高锰酸钾不宜与单宁酸联用来显示血管 相似文献
34.
Anterior pituitary cells of the GH line, which secrete prolactin spontaneously, showed spontaneous action potential activity. Thyrotrophin releasing factor, which increases secretion in these cells, caused a prompt increase of action potential frequency. Potassium, another secretagogue, depolarized the cells and sometimes initiated a burst of action potentials at the onset of this effect. The action potentials persisted in tetrodotoxin-containing and Na-free media, but were suppressed by the Ca-channel blocker, methoxyverapamil. Moreover, elevating the extracellular Ca2+ concentration increased the amplitude of the action potentials. These action potentials therefore have a prominent Ca component. This endows them with a particular interest since secretory activity of these cells is known to be dependent on extracellular Ca2+. Ba2+, which can substitute for Ca2+ in maintaining secretion, also substituted for Ca2+ in the maintenance of the action potentials. In addition, Ba2+ prolonged action potentials remarkably: tetraethylammonium was less effective in this regard.The several parallels between known secretory behaviour and electrical phenomena encourage the view that analysis of electrical activity in anterior pituitary cells may provide useful clues to events involved in stimulus-secretion coupling and in the secretory control exerted by the brain. 相似文献
35.
By use of scanning electron microscopy (SEM), together with energy dispersive chemical analysis, a study has been made of the comparison of an in vitro method of assessing interface reactions between bone and ceramic implants with the naturally occurring changes seen in the rat ear model. Interface reactions between bone and two ceramic materials were examined following 4 wk in culture and 4 wk implantation. In both cases a gradual chemical change occurred at the calcium silicate surface during the fibrous growth onto the ceramic material. Gradual mineralization of the connective fibres was found at the interface of the calcium silicate material, whereas, in the case of alumina ceramic a connective fibrous bond had formed with no associated chemical change at the ceramic surface. 相似文献
36.
Janice S. Lee Carol W. Bassim Harvey Kushner Ann G. Carr Pamela J. Gardner Laura A. Harney Kris Ann P. Schultz Douglas R. Stewart 《American journal of medical genetics. Part A》2019,179(9):1820-1825
Pathogenic germline variation in the microRNA processing gene DICER1 gives rise to an autosomal dominant, tumor‐predisposition disorder. Conditional deletion of Dicer1 in murine dental epithelium shows that it controls tooth patterning, size, number, and shape. The human dental phenotype of people with germline pathogenic variation in DICER1 is unknown. DICER1‐carriers (n = 57) and family controls (n = 55) were evaluated at the NIH Clinical Center dental clinic as part of a comprehensive medical evaluation. Digital panoramic radiographs, bite‐wing radiographs, and oral photographs were collected. A single observer, blind to DICER1 status, reviewed the dental records and determined the presence or absence of 11 dental characteristics as described in the clinic notes, radiographs, or oral photographs. Subjective phenotypes were reviewed on radiographs by two examiners (blind to DICER1 status) for the presence or absence of the dental characteristics to reduce inconsistencies. By simple association, bulbous crown, periodontitis, and taurodontism were all significant (p < .05). Logistic regression with chi‐square maximum likelihood estimates showed that bulbous crown and periodontitis remained significant. Recognition of these phenotypes may aid identification of individuals and families at risk for DICER1‐associated neoplasms. These findings may also guide dental care for individuals with germline DICER1 pathogenic variation. 相似文献
37.
The available drug therapy for post-ischemic neurodegeneration of the brain is symptomatic. This review provides an evaluation of possible dietary therapy for post-ischemic neurodegeneration with myricetin. The purpose of this review was to provide a comprehensive overview of what scientists have done regarding the benefits of myricetin in post-ischemic neurodegeneration. The data in this article contribute to a better understanding of the potential benefits of myricetin in the treatment of post-ischemic brain neurodegeneration, and inform physicians, scientists and patients, as well as their caregivers, about treatment options. Due to the pleiotropic properties of myricetin, including anti-amyloid, anti-phosphorylation of tau protein, anti-inflammatory, anti-oxidant and autophagous, as well as increasing acetylcholine, myricetin is a promising candidate for treatment after ischemia brain neurodegeneration with full-blown dementia. In this way, it may gain interest as a potential substance for the prophylaxis of the development of post-ischemic brain neurodegeneration. It is a safe substance, commercially available, inexpensive and registered as a pro-health product in the US and Europe. Taken together, the evidence available in the review on the therapeutic potential of myricetin provides helpful insight into the potential clinical utility of myricetin in treating neurodegenerative disorders with full-blown dementia. Therefore, myricetin may be a promising complementary agent in the future against the development of post-ischemic brain neurodegeneration. Indeed, there is a scientific rationale for the use of myricetin in the prevention and treatment of brain neurodegeneration caused by ischemia. 相似文献
38.
39.
Zeina Salloum Eric A. Lehoux Mary‐Ellen Harper Isabelle Catelas 《Journal of orthopaedic research》2021,39(1):112-120
Implant wear and corrosion have been associated with adverse tissue reactions that can lead to implant failure. Wear and corrosion products are therefore of great clinical concern. For example, Co2+ and Cr3+ originating from CoCrMo‐based implants have been shown to induce a proinflammatory response in macrophages in vitro. Previous studies have also shown that the polarization of macrophages by some proinflammatory stimuli is associated with a hypoxia‐inducible factor‐1α (HIF‐1α)‐dependent metabolic shift from oxidative phosphorylation (OXPHOS) towards glycolysis. However, the potential of Co2+ and Cr3+ to induce this metabolic shift, which plays a determining role in the proinflammatory response of macrophages, remains largely unexplored. We recently demonstrated that Co2+, but not Cr3+, increased oxidative stress and decreased OXPHOS in RAW 264.7 murine macrophages. In the present study, we analyzed the effects of Co2+ and Cr3+ on glycolytic flux and HIF‐1α stabilization in the same experimental model. Cells were exposed to 6 to 24 ppm Co2+ or 50 to 250 ppm Cr3+. Glycolytic flux was determined by analyzing extracellular flux and lactate production, while HIF‐1α stabilization was analyzed by immunoblotting. Results showed that Co2+, and to a lesser extent Cr3+, increased glycolytic flux; however, only Co2+ acted through HIF‐1α stabilization. Overall, these results, together with our previous results showing that Co2+ increases oxidative stress and decreases OXPHOS, suggest that Co2+ (but not Cr3+) can induce a HIF‐1α‐dependent metabolic shift from OXPHOS towards glycolysis in macrophages. This metabolic shift may play an early and pivotal role in the inflammatory response induced by Co2+ in the periprosthetic environment. 相似文献
40.
Cody C. Wyles Joshua M. Kolz Douglas W. Van Citters Daniel J. Berry Robert T. Trousdale 《The Journal of arthroplasty》2021,36(3):1133-1137
BackgroundThe purpose of this study was to evaluate a series of retrieved sleeved ceramic femoral heads used in total hip arthroplasty (THA) and determine qualitative and quantitative damage and corrosion patterns.MethodsAn IRB-approved implant retrieval database was utilized to identify all sleeved ceramic femoral heads collected from 1995 to 2004. There were 16 implants with an average duration of in situ of 70 months (range, 13-241 months). The femoral stem was known in 14 cases and was titanium alloy in each of those cases. None were revised for metal-related complications. Ten implants (63%) were from primary THAs, and 6 (38%) were from revision THAs. Damage and corrosion were qualitatively graded using a modified Goldberg method. A quantitative assessment was performed with a coordinate measurement machine (CMM).ResultsAmong the 16 retrieved implants, 1 (6%) demonstrated severe Grade 4 corrosion, 5 (31%) had moderate Grade 3 corrosion, 5 (31%) had mild Grade 2 corrosion, and 5 (31%) had no visible corrosion at the inner sleeve that interfaces with the stem trunnion. The only case of grade 4 corrosion occurred in the only head-sleeve in the study that was not factory assembled and was mated with a titanium molybdenum zirconium ferrous (TMZF) alloy stem. The mean maximum linear corrosion depth at the taper interface, as measured by the CMM, was 7.7 microns (range, 0.9-32.9 microns).ConclusionThis study is the first to quantify corrosion at the titanium interface of sleeved ceramic femoral heads. Potentially clinically significant damage and corrosion patterns were observed in a few failed retrievals; however, the majority of cases demonstrated minimal or no damage. 相似文献