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91.
Torsion of noncircular beams results in warping of each cross section. When noncircular cross sections are constrained to remain plane, the resulting shear stress distribution is different from what Saint Venant torsion (with warping) would predict. This has practical implications to the stress analysis of plated long bones subjected to torsional loadings. Analyses in which warping is not allowed predict incorrect stress fields in the plate and bone and overpredict the amount of stress shielding associated with fracture plate fixation. 相似文献
92.
双头加压螺纹钉贴股骨距内固定治疗股骨颈骨折 总被引:8,自引:0,他引:8
在X光电视下采用双头加压螺纹钉贴股骨距内固定治疗新鲜股骨颈骨折42例,随访平均2.5年,其中16例随访3年以上,骨折愈合率95.2%,骨折不愈合并股骨头缺血性坏死率4.76%。认为加压螺纹钉贴股骨距内固定可使钉的受力由较大剪应力变为较大轴向力承受,减少骨折处的剪应力,并加压于骨折端能促进骨折愈合。具有操作简单、进钉准确、创伤小、固定牢靠、并发症少等优点。 相似文献
93.
Prevention of early postmenopausal bone loss using low doses of conjugated estrogens and the non-hormonal,bone-active drug ipriflavone 总被引:2,自引:0,他引:2
Hormone replacement therapy is the optimal therapeutic choice for postmenopausal syndrome. While low doses of estrogens (0.3 mg/day of conjugated estrogens) can counteract neurovegetative menopausal symptoms, higher doses (0.625 mg/day of conjugated estrogens) are required to prevent bone loss in postmenopausal women. Experimental and clinical studies have shown that ipriflavone, a non-hormonal isoflavone derivative, is effective in the prevention and treatment of postmenopausal osteoporosis. The aim of the present investigation was to evaluate the efficacy and toler-ability of ipriflavone and very low doses of equine conjugated estrogens on bone loss in early postmenopausal women. Eighty-three healthy postmenopausal women (50.3±0.7 years) were enrolled for this 1-year multicenter study. All subjects were randomly allocated to receive: double placebo (n=24; group A), placebo plus conjugated equine estrogens 0.30 mg/day (n=31; group B) or conjugated equine estrogens 0.30 mg/day plus oral ipriflavone 200 mg tris in die at meals (n=28; group C), according to a double-masked design. Among women who completed the treatment period (valid completers), those of group A showed a progressive decrease in forearm bone density (FBD; measured by dual photon absorptiometry) that reached 1.7% after 12 months. The women in group B maintained their FBD in the first 6 months of treatment but, at the end of the study, showed a bone loss of 1.4% compared with basal values. By contrast, women in group C showed a significant increase in FBD after 1 year of treatment (+5.6%;p<0.01). Bothvalid completers andintention to treat analyses revealed a significant difference (p<0.05) between group A and group C over the study period. None of the treatments produced significant changes of biochemical markers of bone turnover, while hot flushes and other climacteric symptoms were significantly reduced after the sixth month of treatment in women receiving estrogens. Adverse events were generally mild, and did not differ among the groups. The results of this study suggest that low doses of estrogens combined with ipriflavone could represent a new therapeutic approach to the treatment of the postmenopausal syndrome. 相似文献
94.
牛骨形成蛋白在骨不连中的临床应用 总被引:2,自引:0,他引:2
应用牛骨形成蛋白(bovineBoneMorphogeneticProtein简称b-BMP)成功的治愈13例骨不连病人。经过13个月~29个月随访观察,效果较好。本组病人术前平均已做过1.5次手术。13例病人中,有12例被1次治愈。1例病人再次行内固定加用牛骨形成蛋白的植入也被治愈。骨形成蛋白的应用方式,采用同锻石膏复合后植入骨不连处。平均每个病人植入100mgBMP,13例病人平均治愈时间为4.7个月。术后没有任何并发症。 相似文献
95.
An advanced analysis of the mechanical properties of bone should include information about the microarchitecture of cancellous bone in addition to its density. It has recently been shown that high-resolution quantitative computed tomography and magnetic resonance imaging have the potential to assess such information in a noninvasive way in patients. Both techniques, however, lack sufficient spatial resolution to image the individual trabeculae with true precision. In this work, a new parameter, Ridge number density (RND), is introduced. RND is a measure for the trabecular number, which can be extracted directly from high-resolution three-dimensional (3D) images of patients. We applied the RND technique to a test group of nine healthy, postmenopausal women measured repetitively with a high-resolution 3D peripheral quantitative computed tomography (3D-pQCT) system with 165 × 165 × 165 μm3 voxel size. Simultaneously with the RND determination, the trabecular bone density (TBD) was also assessed in the same volume of interest. The examination site was the distal radius. The intersubject variability of the measured test group was 10.5% for RND and 26.3% for TBD. The root mean square error between first and second examinations (midterm reproducibility) was 1.6% and 1.1%, respectively. RND is determined independently from TBD and pertains to the structure of the cancellous bone. As such, it might add crucial information in cases where bone mass or bone density measurements alone give ambigous results. 相似文献
96.
97.
近3年来,用制备的胎骨充填良性骨肿瘤及病样病变术后骨缺损,经观察10例效果良好。胎骨因其自身组织学和生理学特点,具有抗原性小、诱导成骨活性高,利于“爬行各代”等优点。而且来源丰富、采制简单、储存容易、费用低度,是一种良好的植骨材料,特别适于儿童及年老体弱患者自身取骨困难的骨缺损植骨需要。但其为异体骨,有一定免疫原性,抗支撑强度略差,应注意严格无菌操作、消除免疫原性、配合使用内、外固定等措施。 相似文献
98.
I. V. Avdeev V. I. Seledtsov I. V. Prokopenko G. V. Seledtsova V. A. Kozlov 《Bulletin of experimental biology and medicine》1995,120(2):826-828
After separation of normal murine bone marrow cells in a Percoll density gradient cellular fractions with densities of 1.076
and 1.060 g/ml are capable of suppressing thein vitro growth of leukemia cells. The cytostatic activity of these fractions, however, does not surpass the level of antitumor antiproliferative
activity intrinsic to intact bone marrow cells. These cells were found to be capable of joining the splenocytes, thymocytes,
and lymph node cells in effector cytostatic cooperation and thus enhance the final antitumor effect.
Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N
o
8, pp. 181–183, August, 1995 相似文献
99.
18例慢性肾衰继发性甲旁亢病人发现有锁骨骨吸收。发病部位包括锁骨内端、外端、外1/3下缘及内段下缘4个部位。其中锁骨内、外端骨吸收属软骨下骨吸收,内、外段下缘骨吸收属韧带下骨吸收。作者对锁骨骨吸收的X线表现及发病机制作了讨论。认为锁骨骨吸收是继发性甲旁亢的重要X线征象,对诊断肾性骨病具有重要的意义。 相似文献
100.
Alpha2-HS glycoprotein phenotypes and quantitative hormone and bone measures in postmenopausal women
June E. Eichner Christopher A. Friedrich Jane A. Cauley Mohammad I. Kamboh James P. Gutai Lewis H. Kuller Robert E. Ferrell 《Calcified tissue international》1990,47(6):345-349
Summary It has been suggested that inherited traits play a role in the development of osteoporosis by providing a background for the
modulation of gene expression. In this study, we examine the influence of the different alleles of alpha2-HS glycoprotein (AHSG), a protein of the bone matrix, on quantitative estrogens, estrone and estradiol, and bone measures,
bone area and density. Estrogens provide a protective effect against fractures in older women and were thus included in the
analyses. Isoelectric focusing of AHSG from sera followed by immunoblotting was used to type 163 white post-menopausal women
participating in a clinical trial of the effects of walking on bone loss. Plasma hormones were measured by a combination of
extraction, column chromatography, and radioimmunoassay; bone measures on the dominant radius were determined with computerized
tomography. Analysis of variance was done on estrogen and bone measures after controlling for the effects of age and body
mass index. The two major alleles of AHSG result in three phenotypes, designated AHSG 1-1, AHSG 2-1, and AHSG 2-2. The AHSG
1-1 homozygote showed a decreased concentration of estradiol, the AHSG 2-2 homozygote showed an increased concentration, and
the AHSG 2-1 heterozygote was intermediate (P=0.001). Estrone demonstrated a similar pattern in residual analysis although it did not reach statistical significance. 相似文献