拇指腕掌关节韧带的解剖力学分析及临床意义

目的研究拇指腕掌关节背桡韧带及前斜韧带的解剖学及生物力学特点,测量其弹性模量及延伸率,为伤病时韧带修复提供参考。方法解剖成人男性尸体40例新鲜手标本,制做成大多角骨-韧带-第1掌骨标本,20例保留背桡韧带,20例保留前斜韧带,在生物力学机上测试,测量和计算背桡韧带及前斜韧带的长、宽、厚、最大载荷、弹性模量、延伸率。结果背桡韧带、前斜韧带的最大载荷分别为(213.5±72.4)、(168.7±35.2)N,弹性模量分别为(17.2±6.7)、(9.3±2.5)MPa,延伸率分别为(116.2±21.3)%、(92.7±22.4)%。背桡韧带的最大载荷、弹性模量及延伸率均大于前斜韧带。结论拇指腕掌关节囊内韧带中,背桡韧带刚度较大,韧性较强,对维持关节稳定性起重要作用。前斜韧带刚度较小,韧性较差,韧带退变时容易损伤。拇指腕掌关节炎应该首选重建前斜韧带,且应选用弹性模量及延伸率接近背桡韧带的材料为佳。     

前交叉韧带力学特性差异对膝关节有限元仿真结果的影响

目的研究不同前交叉韧带力学特性对膝关节有限元模拟结果产生的影响。方法基于医学图像数据重建包含主要解剖结构在内的膝关节三维有限元模型,并考虑韧带的横观各向同性特性;用同一种韧带本构方程对3种不同前交叉韧带应力应变力学实验曲线进行参数拟合,对比不同的前交叉韧带力学参数对膝关节运动学和生物力学性能的影响。结果不同的前交叉韧带力学特性会得到不同的膝关节位移结果,前交叉韧带内的应力及应变大小有很大变化,但分布的趋势基本相同。结论选取不同前交叉韧带力学特性曲线会影响膝关节有限元分析的仿真结果,今后在关节组织力学性能的设置、模型的构建及验证中要足够重视。     

拇指腕掌关节囊和韧带的形态特点及其临床意义

目的：为拇指腕掌关节损伤修复与功能重建提供形态学基础。方法：福尔马林固定的成人尸体上肢标本20例（40侧），解剖观察关节囊及其韧带的起止和附着部位，新鲜成人尸体手标本3例（6侧）制成生物塑化连续断面薄片，观察韧带纤维形态、方向。结果：关节囊背侧厚而紧张，掌侧薄而松驰，周围有后斜韧带、前斜韧带、背桡侧韧带、掌侧韧带和掌骨间韧带，背桡侧韧带粗壮。结论：修复和重建关节周围韧带对拇指腕掌关节的稳定有重要作用。     

拇指腕掌关节韧带的解剖学特点及其临床意义

目的　研究拇指腕掌关节韧带的解剖学特点及各韧带在拇指运动中的作用,为韧带重建提供形态学基础。 方法　放大镜下解剖成人男性尸体20例新鲜手标本,观察拇指腕掌关节韧带的起止点及附着部位,分别测量各韧带在中立位下的长、宽、厚及最大拉伸长度,测量关节的活动范围。 结果　拇指腕掌关节周围共5条韧带,其中桡背韧带、后斜韧带、前斜韧带为囊内韧带,第1骨间韧带、尺侧韧带为囊外韧带。在囊内韧带中,最厚的是桡背韧带（2.08±0.27） mm,最薄的是前斜韧带（1.14±0.17） mm。最宽的是前斜韧带（9.33±1.09） mm,最窄的是后斜韧带（7.23±0.88） mm。延伸率最大的是桡背韧带（57.33±9.21%）,最小的是前斜韧带（38.43±8.26%）。 结论　拇指腕掌关节存在三级稳定结构,在关节囊韧带中,桡背韧带厚韧而紧张,对维持关节稳定性起重要作用,前斜韧带薄而松弛,外伤或自发性劳损引起退行性变可能性较大,拇指腕掌关节炎应该首选重建前斜韧带。     

膝关节制动对髌韧带力学特性影响的实验研究

探讨膝关节制动对髌韧带力学特性和影响。我们将兔膝关节伸直位制动６周。然后对制动前后髌韧带的本构方程、极限强度、弹性模量、极限载荷等力学性进行研究．结果显示：正常组与制动组间髌韧带的应力－应变关系理论曲线有明显不同,其材料常数亦有显著差异;制动组髌韧带的极限强度张弹性模校正常组均有明显下降,其极限载荷下降不明显。上述结果表明膝关节制动使得髌韧带所受应力下降,为适应这种改变,组织将进行重塑,从而导致其     

ACL和MCL拉伸力学性质实验研究

目的 研究了10具新鲜成人尸体膝关节前交叉韧带和内侧副韧带的拉伸力学性质,为临床提供生物力学参数.方法 取正常国人新鲜尸体前交叉韧带和内侧副韧带各20个试样进行单向拉伸实验,得出了破坏载荷、强度极限、最大应变、弹性模量.对实验数据以多项式进行拟合,得出了应力-应变曲线和应力-应变关系表达式.结果 前交叉韧带的拉伸强度极限最大应变弹性模量大于内侧副韧带.     

兔髌韧带的非线性本构关系

目的：探讨免髌韧带的非线性本构关系。方法：对髌骨－髌韧带－胫骨组合体标本进行拉伸试验，根据实验数据类型，导出髌韧带的本构方程。结果：兔髌韧带的应力－应变关系可用指数函数来描述，其二个材料常数的值分别为：X1（MPa）＝0．1916±0．055、X2（无量纲）＝114．1930±23．0550，根据其本构方程所作的应力－应变关系理论曲线与实验数据之间拟合良好。结论：结果表明此本构方程是有效的，并可为今后的进一步研究提供必要的实用参数。     

第1掌骨力特性及其意义

目的探讨成人第1掌骨的生物力学特性及其在拇指运动中的意义.方法对未固定成人尸体第1掌骨进行压缩和扭转试验.结果得到压缩负荷-位移关系曲线,应力-应变关系曲线,扭角-应变关系曲线,计算得出本构方程和弹性模量.压缩弹性模量(2517.5±576.7)mPa,扭转弹性模量(737.7±249.7)mPa.结论第1掌骨是各向异性材料,纵向加压时弹性较好,在生理限度内可用广义的Hook定律作为本构方程,横向剪切时表现出粘弹材料特性,第1掌骨对抗纵向变形的能力较强.     

前交叉韧带纤维束力学性质的本构方程

本文对前交叉韧带纤维束在膝关节前错运动中的受力进行了研究。依据韧带在４个不同屈曲角度下前错至５ｍｍ的实验数据，建立了前、中、后３个纤维束力学性质的本构方程，其中纤维束的平均应力为纤维束平均应变与纤维束在韧带中所处位置的函数，并经优化处理确定了方程中的常数。方程预测了纤维束对前错的抵抗力，并与实验值进行了比较     

拇指腕掌关节周围韧带的解剖学分析

目的　解剖拇指腕掌关节周围各条韧带及观察其组织形态学特征,探讨其在拇指腕掌关节稳定性中的作用。 方法　采用大体解剖学方法对10例新鲜冰冻手标本进行解剖,识别拇指腕掌关节周围韧带的连接部位与方向性,对韧带的宽度、长度、厚度进行形态学对比分析。并组织学观察拇指腕掌关节背侧和掌侧韧带细胞数。 结果　确定拇指腕掌关节周围存在7条主要韧带：即由3条背侧韧带（桡背侧韧带、背侧中央韧带、后斜韧带）组成的复合体,厚度分别为(1.24±0.12)、(1.91±0.15)、(1.61±0.12) mm。2条掌侧韧带（前斜韧带、尺侧副韧带）,厚度分别为(0.78±0.11) mm、 (1.03±0.11) mm。2条尺侧韧带（大多角骨-第1掌骨背侧韧带,第1、2掌骨间韧带）,厚度分别为(0.78±0.19) mm、(0.89±0.19) mm。背侧韧带明显厚于掌侧韧带（P<0.01）,桡背侧韧带、背侧中央韧带、后斜韧带的细胞数多于前斜韧带,后斜韧带的细胞数也多于尺侧副韧带,均有统计学差异（P<0.05）。 结论　3条背侧韧带组成粗厚坚韧的复合体,在拇指腕掌关节的稳定中,前斜韧带起着更大的作用。     

Development in in vitro toxicology

There are three principal pressures driving the development of in vitro toxicology: (1) the need for more efficient testing systems to cope with the large number of xenobiotics currently being developed; (2) public pressure to reduce animal experimentation; and (3) a need for a better understanding of the mechanisms of toxicity. Within this, in vitro toxicology is focused on local, systemic, and target-organ toxicity. It is becoming increasingly apparent that a step or decision-tree approach using input of a variety of experimental data (physicochemical properties, biokinetics, cytotoxicity) provides the most efficient system for predicting toxicity. Examples of the use of in vitro toxicity systems for prediction of systemic toxicity and target-organ (liver) toxicity are presented.Originally presented at ECCP 93.     

Seasonal variations in acute toxoplasmosis in pregnant women in Slovenia

Between December 1999 and December 2004, 40 081 pregnant women were examined for toxoplasmosis with Toxo-IgG, Toxo-IgM enzyme immunoassay. Women with positive results were then retested with the Toxo-IgG avidity assay for recent toxoplasmosis. Recent acute toxoplasmosis in pregnant women was found to be significantly more frequent (p < 0.01) during winter than summer. The incidence of acute toxoplasmosis during winter-spring was also significantly more frequent (p < 0.025) than summer-autumn. This phenomenon should be taken into account when formulating preventive measures for toxoplasmosis, especially for pregnant women.     

Age-related changes in polyamines in memory-associated brain structures in rats

Polyamines putrescine, spermidine and spermine are positively charged aliphatic amines and have important roles in maintaining normal cellular function, regulating neurotransmitter receptors and modulating learning and memory. Recent evidence suggests a role of putrescine in hippocampal neurogenesis, that is significantly impaired during aging. The present study measured the polyamine levels in memory-related brain structures in 24- (aged), 12- (middle-aged) and 4- (young) month-old rats using liquid chromatography/mass spectrometry and high performance liquid chromatography. In the hippocampus, the putrescine levels were significantly decreased in the CA1 and dentate gyrus, and increased in the CA2/3 with age. Significant age-related increases in the spermidine levels were found in the CA1 and CA2/3. There was no difference between groups in spermine in any sub-regions examined. In the parahippocampal region, increased putrescine level with age was observed in the entorhinal cortex, and age did not alter the spermidine levels. The spermine level was significantly decreased in the perirhinal cortex and increased in the postrhinal cortex with age. In the prefrontal cortex, there was age-related decrease in putrescine, and the spermidine and spermine levels were significantly increased with age. This study, for the first time, demonstrates age-related region-specific changes in polyamines in memory-associated structures, suggesting that polyamine system dysfunction may potentially contribute to aged-related impairments in hippocampal neurogenesis and learning and memory.     

休克过程中肾上腺髓质素变化的研究进展

Adrenomedullin (AM) is a new peptidergic regulator of vascular function. AM serves as a hormone, which has many biological properties, plays an important role in the many pathophysiological processes, especially shock. This review will highlight the structure, biological properties of AM and the relationship between AM and shock.     

Secular change in menarche in women in Madrid

The age at menarche was estimated by recollection in 1617 women between the ages of 18 and 60 in Madrid and a nearby suburb, Pinto. The population of Pinto is working-class and the Madrid group, taken from residential neighbourhoods , belongs to the upper middle class. In both groups we found a diminution in average age at menarche, from 14.04 to 13.02 years in Madrid and from 14.55 to 13.16 years from about 1935 to about 1965 in Pinto. These changes have been more intense in the group which is less well-off economically, where living conditions have varied much more drastically.     

Pitfalls in TRAP assay in routine detection of malignancy in effusions

Telomerase has been found to be reactivated in a majority of cancers but is inactive in most somatic cells. Our principal goal was to determine the potential use of the telomeric repeat amplification protocol (TRAP) assay as marker for malignancy in cytological effusions. The simple selection criterion was the cytological diagnosis, and routine samples were classified into malignant (58 samples) and nonmalignant (233 samples). Of the malignant samples, 44/58 (76%) were positive by TRAP assay. Of the 14 telomerase-negative cytology-positive samples, RNA integrity was poor in 9, indicating suboptimal sample conservation for molecular analysis. In 3 of the remaining 5 samples with a negative TRAP assay, a high number of malignant cells was observed, and these cells might have been telomerase-negative. Thus, the sensitivity of TRAP assay for the presence of malignant cells was about 76%. In the cytologically nonmalignant effusions, the presence of telomerase activity was observed in 24% (55/233). Of these, 6% were highly suspicious for malignancy, 9% were doubtful, and 9% were cytologically nonmalignant effusions confirmed by a follow-up of 12 mo or more. According to these data, the specificity of the TRAP assay to detect tumor cells in effusions ranged only between 82-91%. Our results indicate that, although the TRAP assay is positive in 6-15% of putative malignant effusions, the relatively high number of TRAP false-negative and false-positive cases renders this test unsuitable for routine diagnostic purposes.