Bone architecture and disc degeneration in the lumbar spine of mice lacking GDF-8 (myostatin).

GDF-8, also known as myostatin, is a member of the transforming growth factor-beta superfamily of secreted growth and differentiation factors that is expressed in vertebrate skeletal muscle. Myostatin functions as a negative regulator of skeletal muscle growth and myostatin null mice show a doubling of muscle mass compared to normal mice. We describe here morphology of the lumbar spine in myostatin knockout (Mstn(-/-)) mice using histological and densitometric techniques. The Mstn(-/-) mice examined in this study weigh approximately 10% more than controls (p<0.001) but the iliopsoas muscle is over 50% larger in the knockout mice than in wild-type mice (p<0.001). Peripheral quantitative computed tomography (pQCT) data from the fifth lumbar vertebra show that mice lacking myostatin have approximately 50% greater trabecular bone mineral density (p=0.001) and significantly greater cortical bone mineral content than normal mice. Toluidine blue staining of the intervertebral disc between L4-L5 reveals loss of proteoglycan staining in the hyaline end plates and inner annulus fibrosus of the knockout mice. Loss of cartilage staining in the caudal end plate of L4 is due to ossification of the end plate in the myostatin-deficient animals. Results from this study suggest that increased muscle mass in mice lacking myostatin is associated with increased bone mass as well as degenerative changes in the intervertebral disc.     

Kinematic analysis of a posterior cruciate retaining mobile-bearing total knee arthroplasty

Using video fluoroscopy, 10 subjects having a mobile-bearing posterior cruciate-retaining total knee arthroplasty were analyzed to determine their in vivo kinematic patterns. Under weight-bearing conditions, while in extension, the average contact position was posterior to the mid-tibia sagittal plane with posterior translation of both condyles to 60 degrees of flexion, followed by anterior translation to 120 degrees of flexion. Under non-weight-bearing conditions, the average condylar contact positions were significantly more anterior from full extension to 90 degrees of knee flexion (P=.01). The average range of motion was 129 degrees under non-weight-bearing conditions and 119 degrees during weight-bearing. Although subjects in this study exhibited variable motion patterns, they are accommodated by the unconstrained optimized articulation of this highly conforming mobile-bearing implant.     

15-year follow-up study of total knee arthroplasty in patients with rheumatoid arthritis

In 25 patients with rheumatoid arthritis, 36 cases of cemented Kinematic total knee arthroplasty were reviewed clinically and radiographically at 13 to 19 years after surgery. The mean age at the time of surgery was 51.6 +/- 8.9 years. According to the follow-up results evaluated with the Hospital for Special Surgery knee scoring system, 28 knees (77.7%) were classified as good or excellent. The mean flexion angle at follow-up evaluation was 99 degrees +/- 24 degrees (10 degrees -140 degrees ). At the tibial or femoral bone-cement interfaces, a radiolucent line was seen in 10 of 36 knees (27.8%) at follow-up evaluation. The survival rate of prostheses with revision as the endpoint was estimated to be 93.7% at 15 years. Kinematic total knee arthroplasty in rheumatoid arthritis patients provided a good long-term outcome.     

Tranexamic acid decreases external blood loss but not hidden blood loss in total knee replacement

Background. Total knee arthroplasty (TKA) is often carried outusing a tourniquet and shed blood is collected in drains. Tranexamicacid decreases the external blood loss. Some blood loss maybe concealed, and the overall effect of tranexamic acid on thehaemoglobin (Hb) balance is not known. Methods. Patients with osteoarthrosis had unilateral cementedTKA using spinal anaesthesia. In a double-blind fashion, theyreceived either placebo (n=24) or tranexamic acid 10 mg kg^–1(n=27) i.v. just before tourniquet release and 3 h later. Thedecrease in circulating Hb on the fifth day after surgery, aftercorrection for Hb transfused, was used to calculate the lossof Hb in grams. This value was then expressed as ml of bloodloss. Results. The groups had similar characteristics. The medianvolume of drainage fluid after placebo was 845 (interquartilerange 523–990) ml and after tranexamic acid was 385 (331–586)ml (P<0.001). Placebo patients received 2 (0–2) unitsand tranexamic acid patients 0 (0–0) units of packed redcells (P<0.001). The estimated blood loss was 1426 (1135–1977)ml and 1045 (792–1292) ml, respectively (P<0.001).The hidden loss of blood (calculated as loss minus drainagevolume) was 618 (330–1347) ml and 524 (330–9620)ml, respectively (P=0.41). Two patients in each group developeddeep vein thrombosis. Conclusions. Tranexamic acid decreased total blood loss by nearly30%, drainage volume by     

Relationship of knee joint proprioception to pain and disability in individuals with knee osteoarthritis.

Proprioception plays an integral role in neuromotor control of the knee joint and deficits in knee joint proprioception are well documented in individuals with knee osteoarthritis (OA). However, the functional relevance of these deficits is not clear. This cross-sectional study evaluated the relationship between knee joint proprioception and pain and disability in a large cohort of individuals with knee OA. Two hundred and twenty participants (145 F, 75 M) with symptomatic knee OA were recruited from the community. Five non-weight bearing active tests with ipsilateral limb matching responses were performed at 20 degrees and 40 degrees flexion to measure knee joint position sense. Pain and disability were assessed by self-reported questionnaires and objective measures of balance and gait. Results showed little association between knee joint position sense variables and measures of pain and disability (r values <0.24, most p>0.05). When comparing participants with the worst and best joint position sense, no significant differences in pain and disability could be found (p>0.05). While our study design does not allow causality to be established, these results suggest that deficits in joint position sense may be due to factors other than pain and that deficits are not large enough to impact upon disability.     

用MDCK细胞为种子细胞体外构建组织工程化肾小管片层的实验研究

目的以MDCK细胞为种子细胞、胶原凝胶复合Matrigel为支架材料,采用组织工程技术体外构建组织工程化肾小管片层,观察不同浓度Matrigel以及静态拉伸作用对MDCK细胞在三维支架中极性重建并形成小管样结构的影响。方法将培养的MDCK细胞与添加不同浓度Matrigel的液态Ⅰ型胶原混合,在12孔板内铸模形成MDCK细胞-胶原片层。通过相差显微镜、HE染色、免疫荧光染色等方法对细胞的生长情况及形成的三维肾小管结构进行比较和鉴定。在此实验的基础上,对片层施加静态拉伸力,观察静态拉伸作用对细胞生长、小管样结构形成的影响。结果随培养时间的延长,各实验组片层内的MDCK细胞逐渐增殖、黏附、聚集。单纯以胶原为支架材料的片层内MDCK形成囊腔状结构;添加Matrigel的胶原片层内MDCK细胞可形成管腔样结构,且低浓度Matrigel的胶原片层内细胞存活率高。静态拉伸作用能够刺激细胞的生长、管腔样结构的形成。结论本研究应用组织工程技术,以MDCK细胞为种子细胞、添加Matrigel的液态Ⅰ型胶原为支架材料,培养过程中施加静态拉伸力,体外成功构建出组织工程化肾小管胶原组织片层,肾脏小管上皮细胞可在该支架材料中完成极性重建的自组装过程。     

5％碳酸氢钠用于单肺通气的临床研究

目的研究5％碳酸氢钠（NaCO3）注射液对OLV患者血液酸碱平衡和肺内分流（Qs／Qt）的影响。方法择期ASAⅠ或Ⅱ级20～60岁行开胸手术60例，随机等分3组。实验l组：空白对照；实验Ⅱ组：5％NanC03注射液30ml；实验Ⅲ组：5％NanC03注射液60ml。三组均采用静吸复合麻醉，诱导：静脉注射芬太尼3to／ks、丙t自酚1．5～2mg／ks、琥珀胆碱1．5mg／kg，维持：吸入1～2％异氟烷、连续输注瑞芬太尼0．1～0．25旭／（ks·min）、间断应用维库溴铵0．02～0．03ms／ks。连续监测BP、HR、S002和PETC02。在麻醉前基础值（T0）、麻醉诱导后双肺通气时（T1）、单肺通气30min时（T2）、手术完毕前双肺通气时（T3）采外周动脉血1ml进行血气分析并计算Qs／Qt。结果三组患者的BP、HR、SpO2、PETC02和PaC02等组间比较差异无统计学意义（P〉0．05）。oH值、PaO2、BE值、Qs／Qt实验组与对照组组间比较差异有统计学意义（P〈0．01和P〈0．05）。结论5％NaHCO3注射液能使OLV下开胸手术患者血液pH值下降减小，使氧离曲线右移减少。手术中患者pH值接近中性或手术前状态，有利于肺血管发挥正常的生理功能、促进HPV（缺氧性肺血管收缩）反应、降低Qs／Qt，而不会影响CO2排除的程度。     

Ability of diffusion-weighted imaging for the differential diagnosis between chronic expanding hematomas and malignant soft tissue tumors

Purpose

To evaluate the potential of diffusion‐weighted imaging (DWI) in distinguishing chronic expanding hematomas (CEHs) from malignant soft tissue tumors.

Materials and Methods

We performed conventional MRI and DWI of six CEHs and 31 malignant soft tissue tumors from 37 patients seen between May 2000 and November 2006. DWI was obtained with a single‐shot echo‐planar imaging (EPI) sequence using a 1.5T MR imager. The mean apparent diffusion coefficient (ADC) value was also calculated. We evaluated MRI findings of CEHs and compared ADC value of CEHs with malignant soft tissue tumors.

Results

On conventional MRI, two of six CEHs were difficult to differentiate from malignant soft tissue tumors based on imaging findings. The mean ADC value of CEHs and malignant soft tissue tumors was 1.55 ± 0.121 × 10^?3 mm²/sec and 0.92 ± 0.139 × 10^?3 mm²/sec (mean ± SD), respectively. The mean ADC value of CEHs was significantly higher than that of malignant soft tissue tumors (P < 0.01). There was no overlap in the minimum ADC values among CEHs and malignant soft tissue tumors.

Conclusion

DWI is useful for differentiating between CEHs and malignant soft tissue tumors. J. Magn. Reson. Imaging 2008;28:1195–1200. © 2008 Wiley‐Liss, Inc.

     

冷冻干燥同种骨临床应用的初步报告

目的：建立现代骨组织库，观察系列冷冻干燥同种骨移植的临床效果。方法：采用深度冷冻、真空冷冻干燥和辐照灭菌等现代技术处理人类骨组织，临床应用系列冻干骨94例，包括骨缺损填充、骨不连植骨、脊柱和关节融合、人工关节翻修、髋臼造盖等，观察近期临床结果。结果：冻干同种骨的理化性能、无菌检测和生物性能完全符合体内植入物的相关国家标准，常温下可保存2年。94例中的90例无明显的免疫排斥反应，优良率为95．76％，成功率为97．87％。结论：冷冻干燥同种骨使用安全，保存和运输方便，可替代临床自体骨移植。