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1.
Osteoporosis and related bone fractures are an increasing global burden in our ageing society. Areal bone mineral density assessed through dual energy X-ray absorptiometry (DEXA), the clinically accepted and most used method, is not sufficient to assess fracture risk individually. Finite element (FE) modelling has shown improvements in prediction of fracture risk, better than aBMD from DEXA, but is not practical for widespread clinical use. The aim of this study was to develop an adaptive neural network (ANN)-based surrogate model to predict femoral neck strains and fracture loads obtained from a previously developed population-based FE model. The surrogate model performance was assessed in simulating two loading conditions: the stance phase of gait and a fall.The surrogate model successfully predicted strains estimated by FE (r2 = 0.90–0.98 for level gait load case, r2 = 0.92–0.96 for the fall load case). Moreover, an ANN model based on three measurements obtainable in clinics (femoral neck length (level gait) or maximum femoral neck diameter (fall), femoral neck bone mass, body weight) was able to give reasonable predictions (r2 = 0.84–0.94) for all of the strain metrics and the estimated femoral neck fracture load. Overall, the surrogate model has potential for clinical applications as they are based on simple measures of geometry and bone mass which can be derived from DEXA images, accurately predicting FE model outcomes, with advantages over FE models as they are quicker and easier to perform.  相似文献   

2.
目的:探讨全髋关节置换术(THA)与双极人工股骨头置换术(BHA)治疗老年股骨颈骨折的临床疗效。方法:选择2013 年7 月-2015 年3 月我院收治的老年股骨颈骨折患者90 例,根据手术方法不同将患者分为全髋关节置换组(THA 组)和双极人工股 骨头置换组(BHA 组),每组45 例。观察并比较两组患者的手术时间、术中出血量、住院时间、术后并发症的发生率及手术效果。结 果:两组患者的手术时间、术中出血量及住院时间比较,差异无统计学意义(P>0.05);THA 组并发症的发生率明显低于BHA 组, 差异具有统计学意义(P<0.05);术后1 年,两组手术优良率比较,差异无统计学意义(P>0.05);术后两年及三年,THA 组手术优良 率明显高于BHA 组,差异具有统计学意义(P<0.05)。结论:THA和BHA 治疗老年股骨颈骨折均具有良好的临床疗效,但THA具 有更好的远期疗效,而且术后并发症的发生率较低。  相似文献   

3.
目的:探讨老年股骨颈骨折患者行全髋关节置换术后麻醉恢复期发生躁动的影响因素。方法:回顾性分析我院老年股骨颈骨折行全麻全髋关节置换术患者46例,根据躁动情况分为躁动组和平静组,每组各23例。比较两组患者术前白蛋白、血红蛋白、白细胞、总胆红素、谷草转氨酶、丙氨酸转氨酶水平;术中失血量、尿量、麻醉时间、心率、舒张压、收缩压水平;躁动组患者各种不良刺激的比例。结果:术前,与平静组相比,躁动组白蛋白、血红蛋白水平较低(P0.05),白细胞计数、总胆红素水平较高(P0.05),谷草转氨酶、丙氨酸转氨酶差异无统计学意义(P0.05);术中,与平静组相比,躁动组尿量水平较低(P0.05),失血量、心率、麻醉时间、收缩压水平较高(P0.05),舒张压差异无统计学意义(P0.05);躁动组不良刺激影响中尿管刺激占比例最高,疼痛刺激其次。结论:老年股骨颈骨折患者行全髋关节置换术后麻醉恢复期躁动与术前白蛋白、血红蛋白、白细胞计数水平,术中失血量、尿量、麻醉时间、心率、收缩压水平,尿管刺激、疼痛刺激、气管导管刺激及体位不当刺激有关。  相似文献   

4.
目的:探讨全髋关节置换术与人工股骨头置换术治疗老年股骨颈骨折的疗效。方法:选择在我院的82例行手术置换治疗的老年股骨颈骨折患者,随机分为观察组和对照组,每组41例。观察组采用全髋关节置换术,而对照组实施人工股骨头置换术。观察并比较两组患者的手术时间、术中出血量、血压、术后引流及髋关节功能等。结果:观察组手术时间、术中出血量及收缩压均显著高于对照组,差异具有统计学意义(P<0.05);术后引流量及并发症的发生率,两组比较无显著性差异(P>0.05)。观察组患者术后Harris评分为(93.25±4.51),对照组患者Harris评分为(82.76±3.82),观察组显著优于对照组,差异具有统计学意义(P<0.05)。结论:与人工股骨头置换术相比,全髋关节置换术用于治疗老年股骨颈骨折具有创伤小,恢复快的临床效果,患者术后髋关节功能恢复情况良好,值得在临床推广应用。  相似文献   

5.
We retrospectively analyzed 1334 patients who were implanted standard gamma interlocking nails® (SGN) to stabilize trochanteric femoral fractures over the years 1992–1998. Reoperation to remove the nails was performed in 37 patients, in 9 of them purely because of pain. Three out of these 9 patients with removed SGN suffered femoral neck fractures in the early postoperative course after having been mobilized to full weight-bearing capacity. This complication was not observed with other implant systems and, considering the notoriously high complication rate of femoral neck fractures, severely reduces the value of the SGN concept per se. These findings in combination with other known shortcomings of SGNs prompted us to conduct an experimental study on the fracture force of excavated femurs addressing the hypothesis that the specific design of the SGN is responsible for the occurrence of fatigue fractures of the femoral neck. Eighteen matched pairs of fresh human cadaveric proximal femurs, which were treated by insertion and removal of (i) SGNs or (ii) dynamic hip screws® (DHS) or (iii) by excavation in the absence of an implant, were subjected to incremental loading cycles and compared to the untreated contralateral femurs. Overall, the fracture force was found to be significantly lower among the treated than among the untreated bones. However, the fracture force required after removal of the DHS system was still significantly higher than for SGN or excavation alone. In this way, our findings demonstrate that removing relatively big implants such as SGN can cause serious complications such as femoral neck fractures. We therefore recommend to leave this type of device in place even after fracture healing except in cases of deep and chronic infection.  相似文献   

6.
目的:探究人工髋关节置换术治疗高龄患者股骨粗隆间骨折的临床疗效。方法:选择40例高龄股骨粗隆间骨折患者并将其随机分为两组,观察组给予人工髋关节置换术治疗,对照组经股骨近端髓内钉内固定术治疗。观察比较两组L2-4椎体骨密度、疼痛程度、髋关节功能恢复情况及Harris评分。结果:治疗后,两组L2-4椎体骨密度均显著高于治疗前(P0.05),且观察组显著高于对照组(P0.05);观察组疼痛比例较治疗前明显降低(P0.05),且显著低于对照组(P0.05);观察组髋关节恢复优良率为95.0%,显著高于对照组(70.0%,P0.05);两组Harris评分均显著高于治疗前(P0.05),且观察组显著高于对照组(P0.05)。结论:采用人工髋关节置换术治疗高龄股骨粗隆间骨折的疗效明显优于经股骨近端髓内钉内固定术治疗,其可有效促进髋关节功能恢复,减轻患者疼痛。  相似文献   

7.
8.
摘要 目的:比较直接前方入路与后外侧入路全髋关节置换治疗股骨颈骨折的疗效及术后髋关节功能的影响因素分析。方法:选取2019年5月至2021年12月徐州医科大学附属医院收治并行全髋关节置换治疗股骨颈骨折患者96例,按照手术方法的不同分为直接前方入路组(n=48)和后外侧入路组(n=48)。观察两组围术期指标、并发症发生情况,比较两组治疗前后Harris评分、视觉模拟评分法(VAS)。并应用单因素、多因素Logistic回归分析患者术后髋关节功能的影响因素。结果:直接前方入路组下床时间、切口长度、住院时间显著短于后外侧入路组,术中失血量、术后引流量显著低于后外侧入路组,而手术时间显著长于后外侧入路组(P<0.05)。直接前方入路组术后1、3个月Harris评分显著高于后外侧入路组,VAS评分显著低于后外侧入路组(P<0.05)。两组术后并发症发生率比较,无统计学差异(P>0.05)。两组治疗6个月后髋关节功能优良率比较,差异无统计学意义(P>0.05)。多因素Logistic回归分析结果显示:体质量指数≥24 kg/m2、术后锻炼时间<3 h/d、合并骨质疏松是接受全髋关节置换治疗的股骨颈骨折患者术后髋关节功能不良的危险因素(P<0.05)。结论:直接前方入路全髋关节置换术较后外侧入路全髋关节置换术短期内优势明显,表现为对患者的创伤更小,术后疼痛程度较轻,有利于患者的髋关节功能恢复。体质量指数≥24 kg/m2、术后锻炼时间<3 h/d、合并骨质疏松是接受全髋关节置换治疗的股骨颈骨折患者术后髋关节功能不良的危险因素。  相似文献   

9.
目的:分析全髋关节置换术用于股骨颈骨折患者的临床效果及对血清骨保护素(OPG)、骨钙素(BGP)、碱性磷酸酶(ALP)、C反应蛋白(CRP)、白细胞介素-6(IL-6)的影响。方法:选择我院2014年3月~2016年3月收治的102例股骨颈骨折患者,按抽签法分为对照组与研究组,每组各51例。对照组采用半髋关节置换术治疗,研究组采用全髋关节置换术治疗。比较两组的临床疗效,治疗前后Harris评分、血清OPG、BGP、ALP、CRP、IL-6水平的变化及术后并发症的发生情况。结果:治疗后,研究组的优良率显著高于对照组(P0.05);两组Harris评分、血清OPG、BGP、ALP、CRP、IL-6水平均较治疗前显著上升,且研究组Harris评分显著高于对照组(P0.05),而两组OPG、BGP、ALP、CRP、IL-6水平比较差异无统计学意义(P0.05)。结论:全髋关节置换术用于股骨颈骨折的临床效果肯定,虽可引起血清OPG、BGP、ALP、CRP、IL-6水平上升,但未增加手术风险。  相似文献   

10.
Roots of Ophiorrhiza prostrata D. Don serve as a rich source of camptothecin (CPT), an anticancer drug. Because of the large-scale collection of its roots, the plant has become a threatened species. The present study accomplishes the induction of adventitious roots as a means for the production of CPT as well as for the large-scale propagation of this anticancer drug plant using leaf and internode explants. The biomass yield and CPT content of adventitious roots induced from different explants were compared to roots developed on ex vitro rooted stem cuttings. Adventitious roots were produced on half-strength Murashige and Skoog (MS) medium supplemented with 10.74 μM α-naphthaleneacetic acid and 2.32 μM kinetin at mean fresh weights of 0.753, 0.739 and 0.748 g roots from leaf, internode and shoot, respectively. CPT yield from in vitro derived roots after 50, 80 and 120 days of incubation (0.028, 0.06 and 0.1% dry weight, respectively) was not significantly different from those harvested at the same age from ex vitro rooted (0.03, 0.06 and 0.13%, respectively) stem cuttings. CPT from subcultured roots derived from solid (0.08%) medium was lower than from suspension culture medium (0.12%). Subsequent cultures of the adventitious roots showed a stable production of CPT (0.16%). The yield of CPT from 360-day-old plant-derived roots was 0.19%. Elicitation using methyl jasmonate and acetyl salicylic acid exhibited no enhancement in CPT yield. In vitro propagation through direct shoot regeneration was achieved from the adventitious roots upon transfer to MS medium with 8.87 μM N 6-benzyladenine (BA) and 2.46 μM indole-3-butyric acid (IBA) with a mean of 21.2 shoots per culture in 50 days. The shoots upon subculture on medium having the same level of BA and IBA underwent rapid proliferation. The shoots transferred to field conditions after in vitro rooting exhibited 95% survival. Adventitious root induction, from leaf and internode explants, enables the feasible production of CPT as well as the large-scale rapid propagation of this species which can safeguard it from extinction.  相似文献   

11.
Contiguous high resolution computed tomography images were obtained at a 1.5 mm slice thickness perpendicular to the neck axis from the base of the femoral head to the trochanteric line in a sample of 10 specimens each of Homo sapiens, Pan troglodytes, and Gorilla gorilla, plus five specimens of Pan paniscus. Superior, inferior, anterior, and posterior cortical thicknesses were automatically measured directly from these digital images. Throughout the femoral neck H. sapiens displays thin superior cortical bone and inferior cortical bone that thickens distally. In marked contrast, cortical bone in the femoral neck of African apes is more uniformly thick in all directions, with even greater thickening of the superior cortical bone distally. Because the femoral neck acts as a cantilevered beam, its anchorage at the neck-shaft junction is subjected to the highest bending stresses and is the most biomechanically relevant region to inspect for response to strain. As evinced by A.L. 128-1, A.L. 211-1 and MAK-VP-1/1, Australopithecus afarensis is indistinguishable from H. sapiens, but markedly different from African apes in cortical bone distribution at the femoral neck-shaft junction. Cortical distribution in the African ape indicates much greater variation in loading conditions consistent with their more varied locomotor repertoire. Cortical distribution in hominids is a response to the more stereotypic loading pattern imposed by habitual bipedality, and thin superior cortex in A. afarensis confirms the absence of a significant arboreal component in its locomotor repertoire. Am J Phys Anthropol 104:117–131, 1997. © 1997 Wiley-Liss, Inc.  相似文献   

12.
The mechanical coupling behaviour of the thoracic spine is still not fully understood. For the validation of numerical models of the thoracic spine, however, the coupled motions within the single spinal segments are of importance to achieve high model accuracy. In the present study, eight fresh frozen human thoracic spinal specimens (C7-L1, mean age 54 ± 6 years) including the intact rib cage were loaded with pure bending moments of 5 Nm in flexion/extension (FE), lateral bending (LB), and axial rotation (AR) with and without a follower load of 400 N. During loading, the relative motions of each vertebra were monitored. Follower load decreased the overall ROM (T1-T12) significantly (p < 0.01) in all primary motion directions (extension: −46%, left LB: −72%, right LB: −72%, left AR: −26%, right AR: −26%) except flexion (−36%). Substantial coupled motion was found in lateral bending with ipsilateral axial rotation, which increased after a follower load was applied, leading to a dominant axial rotation during primary lateral bending, while all other coupled motions in the different motion directions were reduced under follower load. On the monosegmental level, the follower load especially reduced the ROM of the upper thoracic spine from T1-T2 to T4-T5 in all motion directions and the ROM of the lower thoracic spine from T9-T10 to T11-T12 in primary lateral bending. The facet joints, intervertebral disc morphologies, and the sagittal curvature presumably affect the thoracic spinal coupled motions depending on axial compressive preloading. Using these results, the validation of numerical models can be performed more accurately.  相似文献   

13.
The objective of the present study was to test the application of an in vitro assay simulating the digestive hydrolysis of leaf litter by the freshwater snail M. praemorsa, as well as to determine the possible influence of different factors in the efficiency of such process to release biologically available C and N under the forms of reducing sugars and amino acids from two different substrates. A novel approach to construct a model explaining the effect of three main factors (temperature, total reaction time and enzyme:substrate ratio) in the digestive hydrolysis of cellulose and protein present in leaf litter of different nutritive value is used. The methodology combines a factorial design based in the response surface methodology (RSM) and in vitro digestibility assays adapted to the physiology of both plant substrates used (alder and poplar leaves). The model revealed a different influence of the factors in the hydrolysis of two plant substrates, poplar and alder leaves and the main effect was produced by the time available for hydrolysis. A compensation response based in a longer gut retention time for the lower quality substrate was observed in the feeding assays. The use of in vitro assays and RSM provides a useful insight on the effect of factors and mechanisms underlying the observed differences in nutritional value of leaf litter for an aquatic invertebrate, being such differences linked to the whole bioavailability of carbon and nitrogen in headwater streams.  相似文献   

14.
New chemicals are being added each year to the existing burden of toxic substances in the environment. This has led to increased pollution of ecosystems as well as deterioration of the air, water, and soil quality. Excessive agricultural and industrial activities adversely affect biodiversity, threatening the survival of species in a particular habitat as well as posing disease risks to humans. Some of the chemicals, e.g., pesticides and heavy metals, may be genotoxic to the sentinel species and/or to non-target species, causing deleterious effects in somatic or germ cells. Test systems which help in hazard prediction and risk assessment are important to assess the genotoxic potential of chemicals before their release into the environment or commercial use as well as DNA damage in flora and fauna affected by contaminated/polluted habitats. The Comet assay has been widely accepted as a simple, sensitive, and rapid tool for assessing DNA damage and repair in individual eukaryotic as well as some prokaryotic cells, and has increasingly found application in diverse fields ranging from genetic toxicology to human epidemiology. This review is an attempt to comprehensively encase the use of Comet assay in different models from bacteria to man, employing diverse cell types to assess the DNA-damaging potential of chemicals and/or environmental conditions. Sentinel species are the first to be affected by adverse changes in their environment. Determination of DNA damage using the Comet assay in these indicator organisms would thus provide information about the genotoxic potential of their habitat at an early stage. This would allow for intervention strategies to be implemented for prevention or reduction of deleterious health effects in the sentinel species as well as in humans. IITR Communication No. 2656  相似文献   

15.
In an orthotopic murine model of head and neck cancer, combined subcutaneous and intratumoral vaccination with recombinant vaccinia virus expressing interleukin-2 (rvv-IL-2) induced significant tumor regression early on therapy. However, its efficacy was restricted by recurrent tumor growth and loco-regional metastases. In this study, we explored the mechanism of tumor metastasis. We compared the levels of expression of a number of molecules involved in tumor metastasis, which included transforming growth factor-beta1 (TGF-beta1), E-cadherin, matrix metalloproteinases (MMPs): MT1-MMP, MMP-2, MMP-9, their tissue inhibitors (TIMPs): TIMP-1/TIMP-2, and pro-angiogenic factors CD31, VEGF-R2, and iNOS between primary and metastatic tumors by real-time RT-PCR and immunohistochemistry. We detected spontaneous lymph node and tongue metastasis. Metastasis was delayed in rvv-IL-2 treated mice. Cultured tumor cells expressed negligible amount of TGF-beta1. Untreated or metastatic tumors, on the other hand, expressed high levels of TGF-beta1 and secreted TGF-beta1 in the sera of tumor-bearing mice. Levels of TGF-beta1 in the sera suddenly jumped at the time when tumor metastasis started. In the metastatic tumors, levels of MT1-MMP, MMP-2, and MMP-9 were significantly elevated (P < 0.001), while levels of TIMP-1/TIMP-2 and E-cadherin were decreased (P < 0.001) compared to control or primary tumors. Levels of CD31, VEGF-R2, and iNOS were also significantly elevated in the metastatic lesions (P < 0.001). The concurrence of high levels of TGF-beta1 in the sera, expression of proteins involved in metastasis and initiation of metastasis suggested possible role of TGF-beta1 in on setting the metastatic cascade in this model.  相似文献   

16.
Cultures of primary hepatocytes from various species, including human, are used in several applications during pre-clinical drug development. Their use is however limited by cell survival and conservation of liver-specific functions in vitro. The differentiation status of hepatocytes in culture strongly depends on medium formulation and the extracellular matrix environment. We incubated primary rat hepatocytes for 10 days on collagen monolayer and in collagen sandwich cultures with or without serum. Restoration of polygonal cell shape and formation of functional bile canaliculi-like structures was stable only in serum-free sandwich cultures. Variations in general cell viability, as judged by the cellular ATP content, LDH release or apoptosis, were less pronounced between alternative cultures. The intracellular glutathione content was preserved close to in vivo levels especially in serum-free sandwich cultures. Basal activities of cytochrome P450 enzymes (P450) varied strongly between cultures. There was a minor effect on CYP1A but CYP2B activity was only detectable in the serum-free sandwich culture after 3 days and beyond. CYP2C activity was slightly elevated in both sandwich cultures, whereas CYP3A showed increased levels in both serum-free cultures. Inducibility of these P450s was fully maintained over time in serum-free collagen sandwich only. Gene expression was largely constant over time in serum-free sandwich cultures that was closest to liver. This liver-like property was supported by protein profiling results. Taken together, the serum-free collagen sandwich culture of primary rat hepatocytes maintained liver-like features over 10 days and is therefore a suitable model for long-term toxicity and drug-drug interaction studies.  相似文献   

17.
The present paper addresses the following question can a simple regulatory bone remodeling model predict effects of viscosity on the trabecular morphology? For that, we propose an extension of a previous bone remodeling model by taking into account the viscosity properties of the tissue. Zener’s law is used to describe the mechanical behavior of the bone and a specific law of the apparent bone density rate is proposed. Based on stability analysis, numerical simulations are then performed to investigate the viscosity role on simulations of the bone remodeling process. We show that the viscous contribution affects the evolution of the apparent bone density, by slowing down the adaptation process, which seems to be confirmed by simulations with real data obtained from rat tibia.  相似文献   

18.
Summary A technique for cultivating isolated flowers of Brassica napus has been developed. Flowers were harvested at anthesis, the surface of their peduncles was then sterilized and they were cultivated in a hormonefree medium. We used an MS medium supplemented with 3% sucrose as a source of organic carbon. From our experiments, it was concluded that no exogenous growth regulator is required to ensure normal growth and development in vitro. The flowers, and thereafter the pods, can be kept in culture until seed maturity. After 30 days, seed development resulted in three types of seeds: (1) normal, (2) milky and (3) aborted. The results show that the number of seeds per pod was not dependent on the order of flowers on the raceme (except the first 10 flowers and flowers above row 50). Our study supports the validity of this model as an easy tool for studying pollination and early seed development.  相似文献   

19.
The effects of acutely administered streptozotocin in the male guinea pig were studied for a period of 18 days following treatment. A single intracardiac injection of streptozotocin (150 mg/kg) was administered on Day 0. On Day 2, plasma glucose concentrations were not significantly different from control levels. On Day 7 and 18, an oral glucose tolerance test was performed with streptozotocin-treated animals receiving an acute injection of either insulin (18 U/kg, i.m.) or saline 90 minutes prior to glucose loading. On Day 7, streptozotocin-treated animals receiving saline had significantly elevated plasma and urine glucose concentrations at 3 hours after glucose loading when compared to controls. Streptozotocin-treated animals receiving insulin however, had significantly lower plasma glucose concentrations at 3 hours while urinary glucose was equal to control values. The second glucose tolerance test performed on Day 18 yielded similar results. Necropsies were performed on animals that died after Day 6. Lesions found in the streptozotocin-treated animals included: small and irregular pancreatic islets, pyknotic nuclei and degranulation of beta cells, renal proximal tubule swelling and vacuolization, adrenal cortical hyperplasia, hepatocyte vacuolization, and visceral fat atrophy. Animals surviving until Day 18 were sacrificed and found to have significantly elevated kidney and adrenal weights compared to controls. These changes illustrate the effectiveness of streptozotocin in the acute chemical induction of diabetes in an animal model (guinea pig) which, like humans, requires a dietary source of ascorbic acid.  相似文献   

20.
摘要 目的:观察通元针法对体外受精-胚胎移植(IVF-ET)反复种植失败(RIF)患者妊娠结局、性激素和焦虑抑郁影响。方法:前瞻性选取广州中医药大学第一附属医院2019年5月到2021年4月期间收治的IVF-ET RIF患者122例,采用随机数字表法将其分为对照组(61例,常规治疗)和研究组(61例,对照组的基础上接受通元针法治疗)。观察两组临床妊娠率、胚胎种植率,记录治疗期间不良反应发生情况,观察治疗前后子宫内膜厚度和子宫内膜血流参数、性激素和焦虑抑郁的变化情况。结果:研究组的临床妊娠率、胚胎种植率高于对照组(P<0.05)。治疗后,研究组孕酮、雌二醇水平高于对照组(P<0.05)。治疗后,研究组的子宫内膜血流搏动指数(PI)、子宫内膜血流阻力指数(RI)、子宫内膜血流收缩期最高血流速度/舒张末期血流速度(S/D)较治疗前降低,且低于对照组,子宫内膜厚度较对照组更厚(P<0.05)。治疗后,研究组Zung焦虑自评量表(SAS)、Zung抑郁自评量表(SDS)评分低于对照组(P<0.05)。两组不良反应发生率组间对比,无统计学差异(P>0.05)。结论:通元针法用于IVF-ET RIF患者,可有效调节人体性激素,缓解焦虑抑郁心情,改善妊娠结局,安全可靠。  相似文献   

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