Central Obesity in Africans: Anthropometric Assessment of Abdominal Adiposity and its Predictors in Urban Nigerians

Objective

To assess the occurrence of central obesity and identify its predictors in urban Africans using anthropometric tools. Another objective was to evaluate the anthropometric indices and their interaction with various cardiovascular risk factors.

Three-dimensional reconstruction of joint surfaces using a microcomputer

A microcomputer was used to analyse the surface characteristics and geometry of articulating joints. Both hardware configuration and software organisation were described. Data used in this analysis were obtained by sequential resection of entire joints (elbows, metatarsophalangeal joints and knees) secured in an embedding medium. The exposed joint profile after each resection in a bone milling machine was recorded photographically. Each record of freshly cut profile was manually digitised and automatically processed with a desktop microcomputer. The complete structure of these articulating surfaces was reconstructed in three dimensions to be displayed in any desired orientation as a series of parallel, consecutive and uniformly spaced sections. These data have been used to derive information on cartilage thickness, underlying bone structure, orientation and anatomical shape of the joint surfaces. The stored surface geometry may be retrieved at any time for related studies of joint kinematics, joint sizing and prosthetic joint design.     

以踝关节解剖结构及生物力学特征分析慢性踝关节不稳

背景：长期慢性踝关节不稳可引起创伤性关节病及继发粘连关节囊炎,甚至成为永久性功能障碍。 目的：分析踝关节的生物力学,明确慢性踝关节不稳的形成原因,探讨慢性踝关节不稳的诊断方法及治疗方案。 方法：检索1990年1月至2014年12月PubMed数据库和万方医学网,选取与慢性踝关节不稳有关解剖、生物力学、诊治等相关方面的综述及基础实验研究的文章。检索词：“慢性踝关节不稳,踝关节解剖,生物力学,治疗方法,研究进展”和“Chronic ankle instability,Anatomy of ankle joint,Biomechanics,Therapy, Research”。经过筛选后纳入40篇文献,对踝关节解剖学结构、慢性踝关节外侧不稳机制及分级、诊断方法、治疗方法等内容的总结。 结果与结论：慢性踝关节不稳的诊断方法包括踝关节内翻应力试验、踝关节前抽屉试验、超声检测、现代影像学检测;慢性踝关节不稳的治疗方法分为保守治疗和手术治疗,手术可分为非解剖学重建和受损韧带解剖修复。慢性踝关节不稳患者应进行早期的诊断和有效的治疗,应综合踝关节解剖结构、生物力学特征、发病原因、诊断结果等因素决定治疗方案。 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;组织工程全文链接：     

Fibrous tissue on the tibia plateau of the kangaroo. A theory on the pressure absorption of joint surfaces

The central part of the articular surface on the tibia plateau of Macropus agilis consists of fibrous cartilage of soft consistency and the fiber arrangement is macroscopically visible. The peripheral portions of the plateau are covered by hyaline cartilage but do not communicate with the hyaline articular surfaces of the femur, as they are covered by the menisci. The fibrous cartilage covering of the tibia plateau is a compliant or readily deformed pad that could serve the function of deforming enough under high joint loads to allow surrounding regions of the articular cartilage to share in carrying those loads, thereby magnifying the articular contact surface and decreasing the magnitude of the peak unit loads in the region of the fibrous tissue pad. This pressure-absorbing mechanism represents the evolutionary response to the higher articular stress resulting from kangaroo locomotion. © 1994 Wiley-Liss, Inc.     

兔膝关节解剖学特点及在动物模型的意义

目的　研究兔膝关节血管分布及关节囊附着,为兔膝关节动物模型建立提供解剖学基础。  方法     将20只新西兰大白兔麻醉后,4%多聚甲醛灌注固定。解剖分离兔膝关节的动脉来源及分支、暴露兔膝关节囊的附着点。测量各动脉起始处及其在水平方向上和关节囊附着点距髌骨下极的距离。  结果    分布兔膝关节的各动脉距髌骨下极的距离上、下和左、右约为20 mm和5 mm,关节囊的上、下端和左、右侧的附着点距髌骨下极约为10 mm和4.5 mm。  结论　在制备兔膝关节模型时,髌骨下极可设为参考的基准点,并通过距其距离判断手术安全范围。     

Microbiological characteristics of clinical isolates of Cryptococcus neoformans in Taiwan: serotypes,mating types,molecular types,virulence factors,and antifungal susceptibility

This study investigated the microbiological characteristics of 100 clinical isolates of Cryptococcus neoformans species complex, including serotypes, mating types, molecular types, antifungal susceptibility and virulence. The isolates were collected at National Taiwan University Hospital from 1999 to 2004. Eight isolates of C. neoformans from pigeon droppings were also evaluated. Among these isolates, 99 were C. neoformans var. grubii serotype A and one was C. neoformans var. gattii serotype B. All of these isolates were α mating types. PCR fingerprinting, generated by primers M13 and (GACA)₄, and URA5 gene restriction fragment length polymorphism analysis revealed that C. neoformans var. grubii isolates belonged to the VNI (98 isolates) and the VNII (one isolate) types, and the single C. neoformans var. gattii was VGI type. The similar profiles of clinical and environmental isolates suggest that patients might acquire these yeasts from the environment. The MIC₉₀ for fluconazole, itraconazole, 5-flucytosine, voriconazole and amphotericin B against all C. neoformans isolates were 8, 0.5, 4, 0.125 and 0.5 mg/L, respectively. All clinical isolates produced urease, phospholipase, capsule and melanin, but these activities varied with individual isolates. Analysis of six clinical and two environmental isolates with various levels of phospholipase activity indicated a correlation between phospholipase activity and the ability to adhere to the lung epithelial cell line, A549. The extent of cell damage, as indicated by lactate dehydrogenase release, also paralleled the phospholipase activity of these isolates. In addition, production of melanin contributed significant protection against amphotericin B killing of the isolates tested.     

骶髂关节正位放射学分型及其临床意义

目的　探讨骨盆正位X线片上骶髂关节的放射学分型,以指导临床对骶髂关节的认知。 方法　对950例（男475,女475）正常骶髂关节的骨盆正位X线片进行观测。根据骶髂关节间隙的数量及间隙的走行特点,对骶髂关节进行放射学分型。 结果　正常骶髂关节的放射学分型大致可分为3种类型：① I型为双侧单间隙型,男女分别为8.8%（42例)和25.7%（122例);②Ⅱ型为双侧双间隙型,男女分别为79.2%（376例)和46.7%（222例);③Ⅲ型为一侧单间隙,一侧双间隙型,男女分别为12%（57例)和27.6%（131例)。II型又分为四个亚型：①“2”型双间隙,男女分别为0.8%（3例）和6.6%（15例）;②“12”型双间隙,男女分别为56.4%（212例）和69.8%（155例）;③“21”型双间隙,男女分别为2.1%（8例）和1.8%（4例）;④“121”型双间隙,男女分别为41.8%（157例）和19.8%（44例）;III型也分为两个亚型：①左侧单间隙,右侧双间隙型的男女分别为26.3%（15例)和49.6% (65例);②左侧双间隙,右侧单间隙型的男女分别为73.7% (42例)和50.4% (66例)。 结论　正常人骶髂关节的放射学分型以双侧双间隙型最常见,其中又以“12”型双间隙所占构成比最大,但各型构成上有性别差异。     

Detection of Merkel cell polyomavirus on environmental surfaces

The Merkel cell polyomavirus (MCPyV) is a human virus identified recently which is associated with the Merkel cell carcinoma. This virus is also detected frequently in the skin of healthy individuals. The presence of MCPyV has been investigated on environmental surfaces in contact with human skin. Various surfaces in four laboratories, public places, and individual homes were swabbed. Human DNA and MCPyV DNA were detected in swabs by real-time PCR. MCPyV DNA levels were measured before and after DNase treatment in a set of 12 MCPyV DNA-positive samples. A total of 60 environmental surface samples were collected. Fifty-one (85.0%) were positive for human DNA detection and 45 (75.0%) were positive for MCPyV DNA detection. All samples positive for MCPyV DNA were positive for human DNA detection. After DNase treatment, a 1.3 log decrease in MCPyV DNA level was observed indicating that about 5% of viral DNA is protected from DNase degradation and might be associated with infectious virus. These results indicate that MCPyV DNA may be detected on environmental surfaces in contact with human skin. Detection of viral DNA might reflect the presence of infectious viral particles and transmission from environmental source to humans cannot be ruled out.     

生理载荷下健康成人寰枢椎三维瞬时运动的特点

BACKGROUND: The cervical spine of the human body is an important structure carrying the head and connecting the spine. Its volume is small, but its flexibility was great. Activity frequency was highest. Simultaneously, cervical spine is the most complicated bony structure of geometric and kinematic characteristics of human body, bears the physiological load of the head, has functions of flexion and extension, lateral bending and rotation. Therefore, the cervical spine has become one of the most vulnerable structures with degenerative diseases of the spine. Analysis of upper cervical spine biomechanics, recognition and understanding of its normal function and mechanical mechanism will provide a theoretical basis for better treatment of upper cervical spine disorders.     

Physiological incongruity of the humero-ulnar joint: a functional principle of optimized stress distribution acting upon articulating surfaces?

Investigations into the distribution of subchondral bone density in the human elbow have suggested that the geometry of the trochlear notch deviates from a perfect fit with the trochlea, and that the load is transmitted ventrally and dorsally rather than through the centre of the humero-ulnar joint. We therefore decided to make a quantitative assessment of the degree of incongruity between the two components in 15 human specimens (age distribution 60 to 93 years) with different types of joint surface. Polyether casts of the joint cavity were prepared under loads of 10,40,160 and 640 N. The thickness of the casts was then measured at 50 predetermined points, and an area distribution of the width of the joint space represented in a two-dimensional template of the trochlear notch. The reproducibility of this procedure was tested by image analysis. At a load of 10 N, only a narrow space was present ventrally and dorsally in the joint, but in the depths of the trochlear notch a width of 0.5 to 1 mm was recorded in the centre, and up to 3 mm at its medial and lateral edges. Specimens with continuous articular cartilage showed a lower degree of incongruity than those with a divided articular surface. As the load was increased to 640 N, however, the original incongruity between the articular surfaces disappeared almost completely. The joint surfaces became more congruous, probably because of the viscoelastic properties of the articular cartilage and the subchondral bone, and the contact areas merged in the centre of the joint. It is suggested that this physiological incongruity brings about an optimal distribution of stress over the articular surface during the transmission of the load, and it may lead to better nourishment of the articular cartilage by providing intermittent mechanical stimulation and circulation of the synovial fluid.     

Stability of the human upright stance depending on the frequency of external disturbances

During an upright stance of humans, it is usually assumed that a stiffer ankle joint contributes to stabilize the stance. To show that under certain conditions a stiffer ankle joint can reduce the stability, the frequency responses of the moment and the angle of the ankle joint against external disturbances caused by random horizontal translations of the support surface were evaluated in ten healthy adult subjects by varying the difficulty of the task at four levels. When it was difficult to keep the upright stance, the subject tended to make the ankle joint stiffer. The transfer function relating the external disturbance moment to the ankle joint moment showed a larger gain in the high frequency range (>0.3 Hz) compared with the gains obtained under easier conditions. A simulation analysis based on a simple inverted pendulum model also reproduced this tendency. These results indicate that the stiffer ankle joint and the resulting higher ankle moment for high frequency external disturbances enhance the possibility that the center of pressure exceeds the limit arising from the size of the feet and can make the upright stance unstable.     

Influence of hysteresis on joint position sense in the human knee joint

During muscle lengthening in a movement cycle the firing rate of muscle spindles is higher than during shortening. This phenomenon, known as hysteresis, has implications for movement control. Therefore, it should have an impact on joint position sense (JPS), the subject's awareness of the static position of a joint. JPS has been tested on the human knee joint by means of an angle reproduction test. This task included the following sequences. The leg was moved passively, by means of a motor drive, from two different start positions (15 degrees and 75 degrees) to a certain target angle and, after a time of 8 s, it was returned to the start position; subjects had to reproduce the former target angle. Several target angles, mild flexion (30 degrees), intermediate flexion (45 degrees), and strong flexion (60 degrees), were used. Depending on the start position, the movements matching these targets were flexions or extensions. At least for the intermediate position different threshold values should be expected for flexions and extensions, if hysteresis has an impact. Moreover, the JPS measure should show a dependence on movement velocity and independence on distance. Of the variables tested, only movement direction but not movement velocity or distance had a statistically significant impact on the dependent constant angle error (difference between reproduction and target angle). The target angle of 30 degrees was exactly reproduced (-0.14 degrees), independently of the start position. The 45 degrees target angle was significantly underestimated (-4.39 degrees) when matching that position by flexions (starting at 15 degrees) compared to an overestimation (2.27 degrees) when matching that position by extensions (starting at 75 degrees). The target angle of 60 degrees has been constantly underestimated (-3.80 degrees), independently of the start position. Therefore, hysteresis, the dependency of the movement's direction, neglected in the past, should be considered in future tests of JPS or studies considering the role of movement parameters for motor control.     

踝关节胫骨远端关节面缺损生物力学特征的三维有限元分析

BACKGROUND: Studies found that three-dimensional finite element analysis can be used in the study of ankle biomechanics, but research on distal tibial articular surface defect was few.     

Effect of nano- and micro-roughness on adhesion of bioinspired micropatterned surfaces

In this work, the adhesion of biomimetic polydimethylsiloxane (PDMS) pillar arrays with mushroom-shaped tips was studied on nano- and micro-rough surfaces and compared to unpatterned controls. The adhesion strength on nano-rough surfaces invariably decreased with increasing roughness, but pillar arrays retained higher adhesion strengths than unpatterned controls in all cases. The results were analyzed with a model that focuses on the effect on adhesion of depressions in a rough surface. The model fits the data very well, suggesting that the pull-off strength for patterned PDMS is controlled by the deepest dimple-like feature on the rough surface. The lower pull-off strength for unpatterned PDMS may be explained by the initiation of the pull-off process at the edge of the probe, where significant stress concentrates. With micro-rough surfaces, pillar arrays showed maximum adhesion with a certain intermediate roughness, while unpatterned controls did not show any measurable adhesion. This effect can be explained by the inability of micropatterned surfaces to conform to very fine and very large surface asperities.     

关节制动对大鼠膝关节软骨缺损修复的影响

BACKGROUND: Joint immobilization is one of the methods used to treat joint pain and joint injury in the department of orthopedics. Compared with other treatment methods, immobilization can reduce the pain of the damaged synovial joints and avoid the contact stress and friction between the joints. However, immobilization can cause some serious complications such as joint contracture, osteoporosis and cartilage degeneration. OBJECTIVE:To observe the effects of joint immobilization on the repair of cartilage injury of knee joint in rats. METHODS: Osteochondral full-thickness defects (2.5 mm in diameter; 2 mm in depth) were created in the left femoral condyle fossa with a corneal trephine. 36 animals were randomly assigned into immobilization group and control group (n=18 per group). In the control group, animal models were established, without any treatment. In the immobilization group, after model establishment, rats were immobilized by a designed and modified simplified miniature Ilizarov fixator.  RESULTS AND CONCLUSION: (1) Repair rate of cartilage defect: No significant difference in repair rate was detected between immobilization group and control group. (2) Histological staining: Regeneration tissue was mainly fiber cells in both groups. At 8 weeks after surgery, Wakitani score and Mankin score were higher in the immobilization group than in the control group (P < 0.05). (3) Cartilage metabolic marker detection: Compared with the control group, at 8 weeks, C-telopeptide of type II collagen levels in the urine were significantly higher in the immobilization group than in the control group (P < 0.05). (4) Results indicated that persistent immobilization could result in cartilage degeneration, and it was detrimental for cartilage repair. 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     

Influence of anthropometric characteristics on changes in maximal exercise ventilation and breathing pattern during growth in boys

Summary The aim of this study was to investigate the effect of growth on ventilation and breathing pattern during maximal exercise oxygen consumption (VO_2max and their relationships with anthropometric characteristics. Seventy six untrained schoolboys, aged 10.5–15.5 years, participated in this study. Anthropometric measurements made included body mass, height, armspan, lean body mass, and body surface area. During an incremental exercise test, maximal ventilation (V_Emax), tidal volume (V _Tmax), breathing frequency (f _max), inspiratory and expiratory times (t _Imax and t _Emax), total duration of respiratory cycle (t _TOTmax), mean inspiratory flow (V _T/t _Imax), and inspiration fraction (t _I/t _TOTmax) were measured at VO_2max. A power function was calculated between anthropometric characteristics and ventilatory variables to determine the allometric constants. The results showed firstly, that V_Emax, V _Tmax, t _Imax, t _Emax, t _TOTmax, and V _T/t _Imax increased with age and anthropometric characteristics (P<0.001), f _max decreased (P<0.001), and t _I/t _TOTmax remained constant during growth; secondly that lean body mass explained the greatest percentage of variance of V_Emax (62.1%), V _Tmax (76.8%), and V _T/t _Imax (70.6%), while anthropometric characteristics explained a slight percentage of variance of f _max and timing; and thirdly that V_Emax, V _Tmax, and V _T/t _Imax normalized by lean body mass did not change significantly with age. We concluded that at VO_2max there were marked changes in ventilation and breathing pattern with growth. The changes in V_Emax, V _Tmax, and V _T/t _Imax were strongly related to the changes in lean body mass.     

Protein adsorption on polymer surfaces: calculation of adsorption energies

In an attempt to understand the mechanisms of protein adsorption at the solid-liquid interface, we have calculated the interaction potential energy between the protein and the polymer surface by a computer simulation approach. The adsorption of four proteins-lysozyme, trypsin, immunoglobulin F_ab, and hemoglobin-on five polymer surfaces was examined. The model polymers used for the calculation were polystyrene, polyethylene, polypropylene, poly(hydroxyethyl methacrylate), and poly(vinyl alcohol). All possible orientations of the protein on the polymer surfaces were simulated and the corresponding interaction energies for the initial contact stage of protein adsorption were calculated. In the calculation of interaction energies, the hydrophobic interaction was not treated explicitly owing to the difficulty in the theoretical treatment. The results showed that the interaction energy was dependent on the orientation of the protein on the polymer surfaces. The energy varied from - 850 to + 600 kJ/mol with an average of about - 155 kJ/mol. The interaction energy was also dependent on the type of polymer. The average interaction energies of the four proteins with poly(vinyl alcohol) were always lower than those with the other polymers. The interaction energy was not dependent on the protein size. It was found that the dispersion attraction played the major role in protein adsorption on neutral polymer surfaces.     

The effect of lysine acetylsalicylate on joint capsule mechanoreceptors in rats with polyarthritis

Summary Joint capsule mechanoreceptors in arthritic rats are more sensitive to pressure than similar receptors in normal animals. This greater sensitivity was reversed by the intravenous or topical administration of lysine acetylsalicylate in anaesthetised rats in doses of 15 to 50 mgm ASA-equivalent/kg. The reduction in sensitivity began within 5–10 min and reached a minimum mean value of 35% of the control after 35 to 40 min. During this period there was a negative linear or exponential relation between the amplitude of response to a controlled mechanical stimulus and time after administration of lysine acetylsalicylate. Control values of sensitivity were reached about 65–70 min following treatment with lysine acetylsalicylate. The results are interpreted as indicating that the high sensitivity of the arthritic joint capsule receptors is due to locally produced prostaglandins, such as prostacyclin.