不同微型种植体稳定性比较的动物实验

目的评价自攻型和助攻型正畸微型种植体的稳定性，探讨两种种植体生物力学的差别。方法将自攻型组与助攻型组正畸微型种植体（每组各28枚）种植于两只狗的上下颌骨颊侧根间区，植入时测量最高植入转矩，即刻负载水平力约1．96N，持续9周后取出种植体，测量最高去除转矩。结果上、下颌自攻型组最高植入转矩[分别为（5．6±1．1）N·cm和（8．7±2．3）N·cm]均明显高于助攻型组[分别为（3．5±2．1）N·cm和（7．4±1．1）N·cm]，差异均有统计学意义（P〈0．05）。上、下颌自攻型组最高去除转矩[分别为（-6．5±2．2）N·cm和（-7．1±2．0）N·cm]均高于助攻型组[分别为（-5．7±2．3）N·cm和（-6．1±0．5）N·cm]，差异均无统计学意义（P〉0．05）。自攻型组成功率为92．9％，助攻型组成功率为86．7％。结论自攻型种植体有较高的初期稳定性，适于种植在上颌骨及下颌骨骨皮质较薄的部位。     

Torque teno virus DNA titre elevated in idiopathic pulmonary fibrosis with primary lung cancer

Background and objective:   IPF is an independent risk factor for lung cancer, but the mechanism of this association has not fully been elucidated. The role of Torque teno virus (TTV) in respiratory disease is poorly understood, although it has been shown that infection with TTV is associated with the activity and prognosis of IPF. This study aimed to investigate the prevalence and titre of TTV DNA among patients with IPF and lung cancer.
Methods:   The presence of TTV DNA was determined by PCR in the sera of patients with both lung cancer and IPF ( n  = 22), patients with IPF only ( n  = 35), and patients with lung cancer only ( n  = 142).
Results:   TTV DNA was detectable in all patients with both IPF and lung cancer, in 94.3% of the patients with IPF only and 97.2% of the patients with lung cancer only. The TTV DNA titre in the patients with IPF and lung cancer was significantly higher than that in the patients with IPF only or lung cancer only. The percentage of TTV-positive patients with a high TTV titre in the IPF and lung cancer group was significantly higher than that in the IPF only group.
Conclusions:   These findings are the first report on the association between TTV and the complication of lung cancer in IPF and suggest that TTV infection might be associated with the development of lung cancer in IPF.     

不同垂直骨面型错(牙合)矫治后牙(牙合)的补偿

目的:研究不同垂直骨面型错矫治后牙的补偿。方法:选择矫治后满意病例157例,对治疗后头颅定位侧位片进行计算机化的头影测量,以获得垂直骨面型的信息和相应牙各指标的数据,与从治疗后模型上测得的切牙转矩角数据综合后进行相关分析。结果:矫治后仅上中切牙转矩与MP-SN角呈负相关关系(P<0.05),但不同垂直骨面型间切牙转矩的差异无统计学意义。MP-SN角与1-SN、1-PP及1-MP极显著负相关(P<0.001),与OP-SN、OP-MP、OP-PP极显著正相关(P<0.001)。结论:不同的垂直骨面型矫治后上下切牙相对于上下颌基骨的倾斜度和平面的倾斜角度都有补偿性改变,但切牙的转矩未受明显影响。     

Position-dependent torque coupling and associated muscle activation in the hemiparetic upper extremity

Previous studies have demonstrated abnormal joint torque coupling and associated muscle coactivations of the upper extremity in individuals with unilateral stroke. We investigated the effect of upper limb configuration on the expression of the well-documented patterns of shoulder abduction/elbow flexion and shoulder adduction/elbow extension. Maximal isometric shoulder and elbow torques were measured in stroke subjects in four different arm configurations. Additionally, an isometric combined torque task was completed where subjects were required to maintain various levels of shoulder abduction/adduction torque while attempting to maximize elbow flexion or extension torque. The dominant abduction/elbow flexion pattern was insensitive to changes in limb configuration while the elbow extension component of the adduction/extension pattern changed to elbow flexion at smaller shoulder abduction angles. This effect was not present in control subjects without stroke. The reversal of the torque-coupling pattern could not be explained by mechanical factors such as muscle length changes or muscle strength imbalances across the elbow joint. Potential neural mechanisms underlying the sensitivity of the adduction/elbow extension pattern to different somatosensory input resultant from changes in limb configuration are discussed along with the implications for future research.     

Can intraoperative measurement of bone quality help in decision making for cementless unicompartmental knee arthroplasty?

Background

In uncemented total hip arthroplasty (THA), low bone mineral density (BMD) is associated with aseptic loosening. BMD is usually assessed via dual-energy X-ray absorptiometry (DXA) or quantitative computed tomography, which takes time and exposes patients to radiation. Due to its low risk profile, intraoperative measurement of the trabecular stability might be a useful alternative to DXA.

The supine hip extensor manual muscle test: a reliability and validity study

Perry J, Weiss WB, Burnfield JM, Gronley JK. The supine hip extensor manual muscle test: a reliability and validity study. Arch Phys Med Rehabil 2004;85:1345-50.

Objectives

To define the relative hip extensor muscle strengths values identified by the 4 grades obtained with a supine manual muscle test (MMT) and to compare these values with those indicated by the traditional prone test.

Design

Comparison of 4 manual supine strength grades with isometric hip extension joint torque; κ statistic-determined interrater reliability, and analyses of variance identified between grade differences in torque.

Setting

Pathokinesiology laboratory.

Participants

Adult volunteers recruited from local community and outpatient clinics. Reliability testing: 16 adults with postpolio (31 limbs). Validity testing (2 groups): 18 subjects without pathology (18 limbs), and 26 people with clinical signs of hip extensor weakness (51 limbs).

Interventions

Not applicable.

Main Outcome Measures

Supine hip extensor manual muscle grade and isometric hip extension torque.

Results

Reliability testing showed excellent agreement (82%). Subjects with pathology had significant differences in mean torque (P<.01) for the assigned grade 5 (176Nm), grade 4 (103Nm), grade 3 (67Nm), and grade 2 (19Nm). Healthy adults showed significant differences between grade 5 (212Nm) and grade 4 (120Nm) in mean torque (P<.05).

Conclusions

The supine MMT is a reliable and valid method with which to assess hip extension strength.     

对女子手球运动员膝关节屈伸肌群进行等速测试

目的对广东省女子手球队运动员膝关节进行等速向心测试,探讨手球项目运动员膝关节屈伸肌群等速测试特征,为手球项目运动员的力量训练和相关的体育科研提供参考。方法运用CON-TREX等速测试系统对14名广东省女子手球运动员的膝关节进行等速向心测试,选取相对峰力矩、屈伸肌峰力矩比值、平均功率、总功和疲劳指数5个指标来研究手球项目运动员膝关节屈伸肌群的等速测试特征。选取独立样本t检验比较屈肌和伸肌的测试结果。结果膝关节伸肌相对峰力矩值在慢速测试(60°/s)和快速测试(240°/s)时均明显大于屈肌(P<0.01);女手队员膝关节屈伸肌峰力矩比值在快速测试(240°/s)时为76%左右;膝关节屈伸肌平均功率和总功在慢速测试(60°/s)时表现为伸肌大于屈肌(P<0.01),在快速测试(240°/s)时表现为左膝关节伸肌大于屈肌(P<0.05);女手队员膝关节屈伸肌疲劳指数范围在0～0.49之间。结论女手队员膝关节伸肌的最大力量和快速力量大于屈肌;女手队员膝关节屈伸肌峰力矩比值在快速测试(240°/s)时略微偏低,说明女手队员膝关节屈肌快速力量偏低;女手队员膝关节伸肌的快速力量和肌肉工作能力均大于屈肌;女手队员膝关节屈伸肌疲劳指数偏低,说明女手队员膝关节屈伸肌的力量耐力水平比较低。     

Differences between flexion and extension synergy-driven coupling at the elbow,wrist, and fingers of individuals with chronic hemiparetic stroke

ObjectiveThe flexion and extension synergies were quantified at the paretic elbow, forearm, wrist, and finger joints within the same group of participants for the first time. Differences in synergy expression at each of the four joints were examined, as were the ways these differences varied across the joints.MethodsTwelve post-stroke individuals with chronic moderate-to-severe hemiparesis and six age-matched controls participated. Participants generated isometric shoulder abduction (SABD) and shoulder adduction (SADD) at four submaximal levels to progressively elicit the flexion and extension synergies, respectively. Isometric joint torques and EMG were recorded from shoulder, elbow, forearm (radio-ulnar), wrist, and finger joints and muscles.ResultsSABD elicited strong wrist and finger flexion torque that increased with shoulder torque level. SADD produced primarily wrist and finger flexion torque, but magnitudes at the wrist were less than during SABD. Findings contrasted with those at the elbow and forearm, where torques and EMG generated due to SABD and SADD were opposite in direction.ConclusionsFlexion and extension synergy expression are more similar at the hand than at the shoulder and elbow. Specific bulbospinal pathways that may underlie flexion and extension synergy expression are discussed.SignificanceWhole-limb behavior must be considered when examining paretic hand function in moderately-to-severely impaired individuals.     

DamonQ自锁系统中运用双丝技术的转矩力学性能有限元分析

BACKGROUND: In the orthodontic treatment, double wire technique is commonly used to correct the torque of anterior teeth; however, the underlying mechanical mechanisms remain unclear. OBJECTIVE: To study the torque capabilities of DamonQ system through the three-dimensional finite element method. METHODS: Three-dimensional finite element models of Damon Q brackets with different dimension arch wires were established and were grouped according to arch wire with different dimensions. The torque capabilities of Damon Q system with different dimensions and materials arch wire were analyzed. RESULTS AND CONCLUSION: The Damon Q brackets with single or double wires had the same variation of torque, torque angle curve changes under the condition of different size and material arch wires. Torque moment increased gradually with increasing torque angle. Rectangular-round double wires produced larger torque moment compared with single rectangular wire, whereas double round wires produced smaller torque moment compared with single rectangular wire. The torque moment produced by rectangular-round double wires or by single rectangular wire was approximately 2-8 times or 1-5 times more than that by double round wires. The torque moment that rectangular-round double wires produced was larger than that single wire produced in the DamonQ system. In the early clinical practice, we can use double round wires to control root movement. In the middle-term of the treatment, we can use rectangular-round double wires to control root movement as the mild forces produced by them reduce root absorption. This study lays a foundation for the application of Damon Q bracket with double wire technology in the clinic. 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

Bilateral deficit expressions and myoelectric signal activity during submaximal and maximal isometric knee extensions in young,athletic males

The bilateral limb deficit (BLD) describes the difference in maximal or near maximal force generating capacity of muscles when they are contracted alone or in combination with the contralateral muscles. A deficit occurs when the summed unilateral force is greater than the bilateral force. This study examined the presence of the BLD during submaximal (25, 50, 75% of MVC) and maximal (100% MVC) isometric knee extensions in a group of young, athletic males (n = 6, mean age of 22 ± 3 years, mean height = 177.7 ± 6.4 cm, mean weight = 72.4 ± 5.2 kg). Torque and myoelectric signal (MES) data were collected from three superficial muscles of the quadriceps (vastus lateralis, vastus medialis and rectus femoris) during submaximal and maximal isometric knee extensions and it was found that a similar BLD exists using either torque or MES data. MES data showed that there were differences between bilateral and the total unilateral isometric knee extension regardless of percent contraction. This suggests that the BLD may be due to neural mechanisms and that future studies should examine the relationship between torque and the corresponding MES activity.