超声波检测骨密度技术研究

人体骨密度能够体现人体的很多信息,如骨质疏松、骨折、骨龄等。研究利用超声波在固体中产生波形转换的原理,采用一种特殊角度的双晶探头。利用定量超声技术检测出胫骨中超声横波的传播速度SOS（speedofsound）,从中得到的骨密度信息,能够从一种新的角度来对估量减少,骨质疏松进行诊断和预测。分别对不同年龄层的人进行实验。得到的结果验证了系统的正确性。     

Could vagus nerve stimulation influence bone remodeling?

Objectives:To investigate the effect of vagus nerve stimulation (VNS) on the bone mineral density (BMD) in epileptic patients.Methods:A prospective cohort study was conducted on individuals with refractory seizures who underwent VNS surgery between January 2012 and December 2018. BMD was measured preoperatively and between 6 months and one year after surgery.Results:Twenty-one patients (mean age (±SD)=23.6±12.3 years) were recruited for the implantation of a VNS device. The mean absolute increase in lumbar BMD in the 21 patients was 0.04±0.04 g/cm² resulting in an overall percent increase from baseline of 4.7±6.1%. BMD increased by an amount ≥ the least significant change (LSC) for the lumbar spine in 13 patients (61.9%). The lumbar Z score also increased in these patients from -1.22±1.15 to -0.88±1.22, P=0.006). Pre and Post VNA femoral BMD was measured in only 11 patients and, of those 3 showed a significant increase in BMD, 1 a significant decrease and 7 no change.Conclusion:The implantation of a VNS was associated with an increase in lumbar BMD. This study could lead to a new application for VNS in the treatment of osteoporosis.     

DEXA对骨髓炎骨缺损治疗中骨痂密度的评价

目的：探讨DEXA对骨髓炎骨缺损治疗中骨痂密度的评价及意义。方法：严格按照纳入排除标准,选取21例骨髓炎清创后伴大段皮质骨缺损一期植骨的病人。术后4,6,8,10个月后对骨折端骨痂行双能X线骨密度仪检测,并进行X摄片以及Enneking评分,从而明确植骨区愈合骨痂的密度变化趋势,骨愈合情况以及症状改善情况。结果：（1）X线摄片结果显示：4个月后：骨缺损区依然清晰可见,内有少量稀疏骨痂通过,少量外骨痂形成。6个月后：植骨区内骨痂含量明显增多,且外骨痂膨大。8个月：缺损区模糊,有较致密骨痂生成,且外骨痂逐渐减少。10个月：植骨区骨痂更加致密,且部份髓腔再通。（2）Enneking评分：患者术后第10个月功能恢复情况评估正常功能20例,20分以下的患者1例。（3）BMD测定：骨折端的骨密度及骨密度比率随时间延长而增加,植骨10个月后患侧的骨密度已可基本上达到正常对照侧的骨密度水平。结论：双能X线骨密度测量从一定程度上反映出骨痂的力学强度特性。在感染性骨缺损治疗中可以作为检测植骨区的恢复情况的参考。     

Use of biochemical markers to monitor changes in bone turnover in cynomolgus monkeys

The ovariectomized old cynomolgus monkey is a recognized model of human osteoporosis, and the same species can be used for the assessment of the efficacy and potential toxicity of agents intended to prevent or treat osteoporosis. Several assays have been developed that can measure the same biochemical markers of bone turnover as are used in human patients for the diagnosis and treatment follow-up of bone-related diseases, including osteoporosis. The aim of the present study was to describe the results obtained with these assays in normal control monkeys, their variations with age and sex, and their sensitivity in monitoring the bone turnover induced by ovariectomy in old skeletally mature cynomolgus monkeys. Seven old cynomolgus monkeys were bilaterally ovariectomized and 13 age-matched monkeys were sham-operated. Bone mineral density and biochemical markers were measured before and at regular intervals after surgery for up to 20 months. Total alkaline phosphatase (total ALP), bone-specific alkaline phosphatase isoenzyme (bone ALP) and osteocalcin (OC) were highly correlated to the decrease in bone mineral density (BMD) induced by ovariectomy. Deoxypyridinoline (DPD) measured by enzyme-linked immunoassay was insensitive to the bone resorption induced by ovariectomy, but cross-linked N-telopeptide (NTX-I) was higher in ovariectomized monkeys than in control monkeys. These results demonstrate that reliable biochemical parameters are available to adequately monitor and provide insight into osteoclastic bone resorption and osteoblastic bone formation, the two components of bone turnover in this animal model, and can thus be used to assess the efficacy and toxicity of potential therapeutic agents.     

Effect of daily short-duration weight-bearing on disuse-induced deterioration of musculoskeletal system

Objectives:

To investigate deterioration of musculoskeletal system due to prolonged disuse and the potential of daily short-duration weight-bearing as countermeasures.

Methods:

Twenty-four adult male Sprague-Dawley rats were divided into Control Group (CG, no intervention), Tail-suspension Group (TG, tail-suspension without treatment), and Weight-Bearing Group (WBG, tail-suspension with 20 min/day, 5 days/week body weight loading). After four weeks of treatment, femur and tibia, soleus and extensor digitorum longus were evaluated for bone and muscle quality respectively. Tensile properties of bone-tendon insertion (BTI) were evaluated using patella-patellar tendon complex.

Results:

Disuse induced deterioration on bone, muscle, and BTI after four weeks. Compared with CG, TG and WBG showed significant decrease in bone mineral density (BMD) of trabecular bone in distal femur (4.3-15.2%), muscle mass (31.3-52.3%), muscle cross-sectional area (29.1-35%), and failure strength of BTI (23.9-29.4%). Tensile test showed that the failure mode was avulsion of bone at the BTI. No significant difference was detected between TG and WBG for all assessments on bone, muscle, and BTI.

Conclusions:

Disuse caused deterioration of bone, muscle, and BTI while daily short-duration of weight-bearing did not prevent this deterioration. Mechanical stimulation with higher intensity and longer duration may be necessary to prevent musculoskeletal deterioration resulted from prolonged disuse.     

The effects of whole body vibration on mobility and balance in children with cerebral palsy: a systematic review with meta-analysis

Objective:

We performed a meta-analysis to evaluate the effects of whole-body vibration on physiologic and functional measurements in children with cerebral palsy.

Design and methods:

We searched MEDLINE, Cochrane Controlled Trials Register, EMBASE, Scielo, CINAHL (from the earliest date available to November 2014) for randomized controlled trials, that aimed to investigate the effects of whole-body vibration versus exercise and/or versus control on physiologic and functional measurements in children with cerebral palsy. Two reviewers independently selected the studies. Weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated.

Results:

Six studies with 176 patients comparing whole-body vibration to exercise and/or control were included. Whole-body vibration resulted in improvement in: gait speed WMDs (0.13 95% CI:0.05 to 0.20); gross motor function dimension E WMDs (2.97 95% CI:0.07 to 5.86) and femur bone density (1.32 95% CI:0.28 to 2.36). The meta-analysis also showed a nonsignificant difference in muscle strength and gross motor function dimension D for participants in the whole-body vibration compared with control group. No serious adverse events were reported.

Conclusions:

Whole-body vibration may improve gait speed and standing function in children with cerebral palsy and could be considered for inclusion in rehabilitation programs.     

The association between major depressive disorder,use of antidepressants and bone mineral density (BMD) in men

Objective:

Both depression and use of antidepressants have been negatively associated with bone mineral density (BMD) but mainly in studies among postmenopausal women. Therefore, the aim of this study was to investigate these relationships in men.

Methods:

Between 2006 and 2011, 928 men (aged 24-98 years) from the Geelong Osteoporosis Study completed a comprehensive questionnaire, clinical measurements and had BMD assessments at the forearm, spine, total hip and total body. Major depressive disorder (MDD) was identified using a structured clinical interview (SCID-I/NP). The cross-sectional associations between BMD and both MDD and antidepressant use were analyzed using multivariable linear regression.

Results:

Of the study population, 84 (9.1%) men had a single MDD episode, 50 (5.4%) had recurrent episodes and 65 (7.0%) were using antidepressants at the time of assessment. Following adjustments, recurrent MDD was associated with lower BMD at the forearm and total body (-6.5%, P=0.033 and -2.5%, P=0.033, respectively compared to men with no history of MDD), while single MDD episodes were associated with higher BMD at the total hip (+3.4%, P=0.030). Antidepressant use was associated with lower BMD only in lower-weight men (<75-110 kg depending on bone site).

Conclusions:

Both depression and use of antidepressants should be taken into account as possible risk factors for osteoporosis in men.     

Examination of spinal column vibrations: a non-invasive approach

Accelerations of vertebrae during whole-body vibration (WBV) are used in occupational biomechanics for the prediction of internal stress. To avoid invasive techniques, a method for the calculation of bone accelerations was developed using measurements on the skin. The soft tissue between spinous processes L3 and T5 and miniature accelerometers stuck to the skin over them was modelled by a simple Kelvin element, whose parameters i.e. angular natural frequency omega n and critical damping zeta, describe an approximate transfer function between the bone (input) and the skin surface (output). The parameters were determined from free damped oscillations of the accelerometer-skin complex in the Z-axis, and depended significantly on the factors "subject" and "point of measurement". In one subject, the time courses of bone accelerations during sinusoidal WBV (4.5 and 8 Hz; 1.5 m.s-2 RMS) were calculated using separate transfer functions for each of 11 different spinal levels. Since the output signals on the skin were non-sinusoidal, the skin accelerations had to be treated with an inverse transfer function in the frequency domain. A comparison of accelerations measured on the skin and predicted for the bone mainly indicates that absolute peak values of bone accelerations are smaller and occur earlier. Both kinds of acceleration hint at differences in WBV-induced internal stress within the spine.     

Acute bone response to whole body vibration in healthy pre-pubertal boys

The skeleton responds to mechanical stimulation. We wished to ascertain the magnitude and speed of the growing skeleton’s response to a standardised form of mechanical stimulation, vibration. 36 prepubertal boys stood for 10 minutes in total on one of two vibrating platforms (high (>2 g) or low (<1 g) magnitude vibration) on either 1, 3 or 5 successive days (n=12 for each duration); 15 control subjects stood on an inactive platform. Blood samples were taken at intervals before and after vibration to measure bone formation (P1NP, osteocalcin) and resorption (CTx) markers as well as osteoprotegerin and sclerostin. There were no significant differences between platform and control groups in bone turnover markers immediately after vibration on days 1, 3 and 5. Combining platform groups, at day 8 P1NP increased by 25.1% (CI 12.3 to 38.0; paired t-test p=0.005) and bone resorption increased by 10.9% (CI 3.6 to 18.2; paired t-test p=0.009) compared to baseline. Osteocalcin, osteoprotogerin and sclerostin did not change significantly. The growing skeleton can respond quickly to vibration of either high or low magnitude. Further work is needed to determine the utility of such “stimulation-testing” in clinical practice.     

Effects of whole-body vibration on acute bone turnover marker responses to resistance exercise in young men

Objective:

We investigated acute bone turnover marker (BTM) responses to high-intensity resistance exercise with and without whole-body vibration (WBV) in young men (n=10).

Methods:

In this randomized crossover study, subjects performed 2 protocols separated by 2-week wash out periods: 1) resistance exercise only (RE) (3 sets 10 repetitions 80% 1RM for 9 exercises); and 2) WBV + RE (side-alternating vibration platform 5 intermittent, 1-minute bouts 20 Hz, 3.38 mm peak-to-peak displacement followed by RE). Fasting morning blood draws were taken before RE or WBV (PRE), immediately post RE (IP), and 30 minutes post RE (30P). WBV + RE also had a blood draw after the WBV exposure (POST WBV). Blood samples were analyzed for lactate, hematocrit, bone-specific alkaline phosphatase (Bone ALP, U/L), C-terminal telopeptide of type I collagen (CTX-I, ng/mL) and tartrate-resistant acid phosphatase 5b (TRAP5b, U/L).

Results:

Lactate, hematocrit, and Bone ALP significantly increased (p<0.05) IP for both protocols. Bone resorption markers did not change during RE only. CTX-I significantly decreased POST WBV. TRAP5b increased POST WBV, then significantly decreased at 30P.

Conclusions:

Generally, BTM changes to RE only were not significant when adjusted for hemoconcentration. The WBV stimulus altered bone resorption marker but not bone formation marker responses.     

熊果酸对酒精性骨质疏松大鼠骨形成、骨矿化的影响

目的：探讨熊果酸对酒精所致骨质疏松大鼠骨形成、骨矿化的影响。方法：雄性Wistar大鼠60只,按体重随机分为空白对照组、熊果酸对照组、模型组、熊果酸低、中、高剂量组,同时分别给予生理盐水、150 mg/kg 熊果酸、50%酒精,50 mg/kg 熊果酸,100mg/kg 熊果酸,150 mg/kg 熊果酸灌胃。熊果酸对照组生理盐水剂量同空白组,熊果酸低、中、高剂量组酒精剂量同模型组。灌胃共持续8 周。磷钼酸法检测血清磷(P)含量,比色法检测血清钙(Ca)含量,酶联免疫吸附（ELISA）法检测血清骨钙素(BGP)、骨形成蛋白-2(BMP-2)浓度;HE 染色法观察股骨结构的病理学变化。结果：与空白对照组相比较,模型组血清BGP、BMP-2 和Ca、P 均明显降低,且有统计学差异(P < 0.05),但熊果酸对照与空白对照组各项指标结果相近。熊果酸中、高剂量组大鼠血清BGP、Ca 和P 水平均较模型组有显著升高,差异具有统计学意义(P < 0.05),但仅熊果酸高剂量组血清BMP-2 显著升高(P < 0.05)。股骨组织HE染色结果显示,空白对照组骨小梁致密、规则且较粗,粗细均匀;模型组骨小梁稀松、不规则、粗细不均匀,甚至可见骨小梁断裂;熊果酸中、高剂量组骨小梁致密、规则、较厚、粗细均匀,未见骨小梁断裂。结论：熊果酸能够促进酒精性骨质疏松大鼠的骨形成,抑制骨矿物质的流失,在改善酒精致骨质疏松方面有一定的保护作用。     

Effect of Homocysteine on Bone Mineral Density of Rats

The relationship between plasma levels of homocysteine (Hcy) and femur bone mineral density (BMD) was studied in Wistar rats. After 8 weeks of treatment with 0.5 and 1.0 g kg⁻¹ day⁻¹ l-methionine the mean plasma levels of Hcy were 7.67 ± 1.25 and 61.2 ± 11.4 μmol/l, respectively. Only rats treated with the higher dose had Hcy levels significantly higher than those of controls, 6.38 ± 0.90 μmol/l (p < 0.001). Dual Energy X-ray Absorptiometry was used to measure the BMD, which was significantly lower only in the animals with the highest plasma levels of Hcy (p < 0.001). This led us to conclude that increased levels of Hcy are associated with risk of decreased BMD.     

Determination of mineral content and organic matrix in bone samples using dual photon absorptiometry

An application of dual photon absorptiometry for measuring Bone Mineral Content (BMC) and the amount of organic matrix in bones in vitro is described. Dual photon absorptiometry was performed using a¹⁵³Gd source and a Gammatec GT 50 scanner. Although the method is well known in clinical research of osteoporosis and has previously been described, the fundamental principles of the method are demonstrated graphically as this paper is directed to a new audience. Measurements on 9 sections of autopsy and 11 sections of archaeological femoral bones showed that the sum of measured mineral and measured organic matrix was consistent with the weight of the sections with an accuracy of 1.1. and 3.3. per cent respectively. As a further control of the reliability of the method, nine sections were ashed by heating to 800°C for 14 hours. A high correlation could be demonstrated between BMC and ash-weight as well as between the organic matrix and the loss of weight during heating.