Dynamometer for rat plantar flexor musclesin vivo

A dynamometer is designed and fabricated to measure the force output during static and dynamic muscle actions of the plantar flexor muscles of anaesthetised rats in vivo. The design is based on a computer-controlled DC servomotor capable of angular velocities in excess of 17.5 rad s⁻¹. The system controls the range of motion, angular velocity and electrical stimulation of the muscles, while monitoring the force output at the plantar surface of the foot. The force output is measured by a piezo-electric load cell that is rated at 5 kg capacity. Angular velocity and position are measured by a DC tachometer and potentiometer, respectively. All measurement devices are linear (r²=0.9998). The design minimises inertial loading during high-speed angular motions, with a variation in force output of less than 0.2%. The dynamometer proves to be an accurate and reliable system for quantifying static and dynamic forces of rat plantar flexor muscles in vivo.     

Relationship between passive properties of the calf muscles and plantarflexion concentric isokinetic torque characteristics

The purpose of this study was to use a model of aging to examine the relationships between passive properties of the calf muscles and plantarflexion concentric isokinetic torque characteristics. Eighty-one active women 20–84 years of age were tested using a Kin-Com isokinetic dynamometer interfaced with electromyography (EMG). The passive properties were tested by stretching the muscles from relaxed plantarflexion to a maximal dorsiflexion (DF) angle at a rate of 5°·s^–1 (0.087 rad·s^–1) with minimal raw EMG activity (<0.05 mV). The maximal concentric torque was tested from maximal passive DF into plantarflexion at four randomly ordered velocities of 30, 60, 120, and 180°·s^–1. Pearson correlation coefficients (Bonferroni adjusted) indicated a hierarchical order of high to moderate positive correlations between four passive properties and the peak and mean concentric torque for all test velocities. Correlation coefficients for the four passive properties ranged from 0.50 to 0.78 (P<0.001), and the coefficients of determination (r ²) from higher to lower were: (1) maximal DF passive resistive torque (r ²: 0.50–0.62), (2) length extensibility (r ²: 0.40–0.49), (3) maximal muscle length (r ²: 0.28–0.41), and (4) passive elastic stiffness in the last half of the full-stretch range of motion (r ²: 0.25–0.31). The maximal DF passive resistive torque and the length extensibility accounted for 50–62% and 40–49% of the variability in the concentric torque, respectively. The results indicate that the concentrically stronger calf muscles of active women were positively correlated with passively stronger, longer, and stiffer calf muscles, which are characteristics of the calf muscles of younger women. Further studies are needed to examine whether therapeutic interventions, such as stretching and strengthening, can promote adaptations in the calf muscles of older women to attain these more youthful characteristics. Electronic Publication     

Cytoarchitecture and musculotopic organization of the facial motor nucleus in Cebus apella monkey

The architecture and musculotopic organization of the facial motor nucleus in the Cebus apella monkey (a New World primate) were investigated using histological techniques and a multiple labelling strategy, in which horseradish peroxidase‐conjugated neuroanatomical tracers (CTB‐HRP and WGA‐HRP) and fluorescent tracers were injected into individual facial muscles. The facial motor nucleus was formed by multipolar motoneurons and had an ovoid shape, with its rostrocaudal axis measuring on average 1875 µm. We divided the nucleus into four different subnuclei: medial, intermediate, dorsal and lateral. Retrograde labelling patterns revealed that individual muscles were innervated by longitudinal functional columns of motoneurons. The columns of the orbicularis oculi, zygomaticus, orbicularis oris, auricularis superior, buccinator and platysma muscles were located in the dorsal, intermediate, lateral, medial, lateral and intermediate subnuclei, respectively. However, the motoneuron columns of the levator labii superioris alaeque nasi muscle and frontalis muscle could not be associated with a specific subnucleus. The present results confirm previous studies regarding the musculotopic organization of the facial motor nucleus. However, we observed some particularities in terms of the relative size of each column in C. apella, which might be related to the functional and behavioral importance of each muscle in the particular context of this primate.     

茶多酚对正常大鼠及糖尿病大鼠右室乳头肌收缩功能的影响

目的：研究不同浓度的茶多酚（TP）对于正常大鼠及糖尿病大鼠成模后第6周、第8周右室乳头肌收缩功能的影响。 方法： 以四氧嘧啶复制糖尿病大鼠模型，将成模后第6周、第8周糖尿病大鼠右心室乳头肌游离，置于氧合台氏液中，电刺激状态下，记录乳头肌收缩功能，观察不同浓度的茶多酚的影响，并与对照组大鼠进行比较。 结果： 成模糖尿病大鼠第6周时舒张1/2间期延长（P<0.05），收缩速度:+dT/dtmax，-dT/dtmax均降低(P<0.01,P＜0.05)，至第8周张力增量，收缩速度:+dT/dtmax，-dT/dtmax降低（P<0.01）,舒张1/2间期延长（P<0.01）。正常SD大鼠和糖尿病大鼠右室乳头肌给予不同浓度的茶多酚，在15-120 mg/L的浓度范围内，茶多酚对于正常大鼠可以产生正性肌力作用;虽然糖尿病6周大鼠的右室乳头肌收缩功能有所降低,但对茶多酚产生与正常大鼠相似的反应，而糖尿病8周的大鼠对于茶多酚无明显反应。 结论： 茶多酚应用于早期的糖尿病性心肌病，可以产生正性肌力作用，但是对于有严重的心肌损害的糖尿病大鼠心肌，不能产生正性肌力作用。     

Distribution of house dust mite allergen: comparing house dust mite allergen levels in dust samples collected from different sites on living room floors with smooth coverings

BACKGROUND: The distribution of house dust mite allergen (Der p1) in living rooms with smooth floor coverings, as measured in the middle compared with the border of the floor was investigated. It was hypothesized that activity causes displacement of Der p1, from the middle towards the border. METHODS: Dust samples from the middle and border of 50 floors with smooth coverings were collected and analysed on Der p1 content in a standardized way. RESULTS: The Der p1 exposure expressed as per unit area (ng/m2) showed that border samples contained significantly more Der p1 compared with middle samples (median: 2.57 vs 0.27, respectively, P = 0.023). Presence of pets and presence of more than two inhabitants increased the difference. When expressed as per unit weight of dust (ng/g), significant differences were only detected when comparing Der p1 content of samples collected in households with three or more inhabitants [median: 2 (border) vs 53 (middle), respectively; P = 0.035]. CONCLUSIONS: The Der p1 is unequally distributed on living room floors with smooth coverings, most likely because of displacement of dust from the middle towards the border due to activity. Expression as ng/g of dust and ng/m2 could not obviously be interchangeable.     

Histological characterization of neurones innervating functionally different muscles of Locusta

The innervation of four functionally different muscles (subalar, remotor 1, remotor 2, pleuroalar), all served by the same nerve branch, was studied in both winged segments of the locust, Locusta migratoria. Several anatomical techniques were applied: With the cobalt backfill and silver intensification technique four cell types (motoneurone, dorsal unpaired median neurone, common inhibitory neurone, and small median neurone) were demonstrated. Serial sections enabled the morphology of the motoneurones to be described in more detail and in respect to a possible functional organization of the arborizations. A differential staining technique allowed us to stain various neurones in different colours in the same preparation. With this technique the anatomy of both the "rostral" and the "caudal" subalar motoneurones could be described in parallel, thus avoiding errors in comparison due to possible individual variations from preparation to preparation. Axon counts in the peripheral nerve branch enabled us to compile a list of the total innervation for each muscle. Results from other orthopterans are integrated and whether differences in the dendritic fields might be of functional significance is discussed.     

Evaluation of LY163443, 1-[2-hydroxy-3-propyl-4-{[4-(1H-tetrazol-5-ylmethyl)phenoxy]methyl}phenyl]ethanone,as a pharmacologic antagonist of leukotrienes D4 and E4

Summary LY163443,1-[2-hydroxy-3-propyl-4-{[4-(1H-tetrazol-5-ylmethyl)-phenoxy]methyl}phenyl]ethanone, antagonized LTD₄-induced contractions of guinea pig ileum, trachea, and lung parenchyma. Tracheal contractions to LTE₄ were also inhibited by LY163443. The compound had minimal effect against ileal responses to LTC₄ and parenchymal contractions to LTB₄. Furthermore, LY163443.had little to no effect against contractions of isolated smooth muscles to histamine, bradykinin, PGF₂, carbachol, serotonin or U46619. LY163443, given by oral administration to guinea pigs, blocked LTD₄-induced increases in total pulmonary impedance (TPI). Similar responses elicited by histamine or U46619 were unaffected. Increases in TPI in response to i.v. administration of LTC₄ were antagonized by LY163443 given by the same route. Ovalbumin challenge also increased TPI in guinea pigs previously sensitized against this antigen. In such animals, pretreated with pyrilamine, propranolol, and indomethacin, oral administration of LY163443 blocked the increase in TPI caused by ovalbumin. Additionally, LTD₄ given intradermally to guinea pigs caused a vascular leakage which was suppressed by prior oral administration of LY163443. Finally, LY163443 relaxed isolated guinea pig trachea previously contracted with LTD₄, histamine, or carbachol. Relaxation of tissues contracted by these latter two agonists suggested some inherent airway smooth muscle relaxant properties of the molecule. This was further demonstrated by showing some bronchodilator activity in an in vivo setting. Thus, this pharmacologic profile indicates that LY163443, or a member of the same chemical family, warrants consideration as a possible therapeutic agent in the treatment of asthma and in diseases characterized by an overproduction of LTD₄ and LTE₄.Presented in part at the meeting of The Federation of American Societies for Experimental Biology, April 1985, Anaheim, California.     

产后妇女盆底肌损伤发生情况调查研究

目的 探讨产后妇女盆底肌功能情况并分析造成妇女产后盆底肌损伤的相关因素,为预防妇女因生产造成盆底肌损伤提供科学依据。方法 以2019年1月至2020年11月在湖南省长沙市和株洲市各1家医院产科进行6~8周产后复查的产妇为研究对象进行资料收集及盆底肌力测定,采用描述流行病学分析方法进行盆底肌力异常情况分析,并采用单、多因素分析方法对产后妇女盆底肌异常影响因素进行分析。结果 本研究共对1 628名产妇进行调查,年龄22~38岁,平均（29.68±5.36）岁;孕次1~5次,平均孕次（2.43±1.16）次;产次1~5次,以1~2次为主,占72.4%。检出1 142例产后6~8周产妇为盆底肌力异常,异常率为70.2%。年龄30~38岁（OR=3.766）、产次≥3次（OR=2.633）、阴道分娩（OR=7.478）、孕期增重过多（OR=1.597 ）及胎儿出生体重≥4 kg（OR=5.078）的产后妇女盆底肌力异常的风险较高。结论 湖南省产后妇女盆底肌力异常率较高,年龄、产次、分娩方式、孕期增重及胎儿体质量是造成产妇产后发生盆底肌损伤的重要原因,应采取相应措施,降低产后妇女发生盆底肌损伤风险。     

旋后肩法处置肩难产对产妇分娩后盆底肌功能改善的临床研究

目的探讨旋后肩法用于肩难产产妇,对其产后盆底肌功能的改善作用。 方法选择2018年7月至2020年1月,在宁波市妇女儿童医院采用旋后肩法完成肩难产助产的28例产妇为研究对象,并纳入研究组。选取同期在本院分娩,采用耻骨联合上加压法完成肩难产助产的25例产妇纳入对照组。采用表面肌电图(sEMG),获取2组产妇分娩8周后盆底肌收缩运动肌电值。采用成组t检验,对2组产妇一般临床资料、盆底sEMG检测结果进行统计学分析。采用χ²检验,对2组产妇分娩巨大儿所占比例等进行统计学分析。本研究遵循的程序符合病例收集医院伦理委员会制定的伦理学标准,得到该委员会批准[审批文号：[2018]伦审字(28)号]。与所有受试者签署临床研究知情同意书。 结果①2组产妇身高、体重,分娩时人体质量指数(BMI)、孕龄、年龄等一般临床资料比较,差异均无统计学意义(P>0.05)。②2组产妇分娩新生儿的出生体重和巨大儿所占比例分别比较,差异亦均无统计学意义(P>0.05)。③研究组产妇前基线值、快肌收缩最大值、混合肌收缩最大值、混合肌收缩平均值、耐力肌收缩平均值、后基线值分别为(1.4±0.3) μV、(23.8±5.5) μV、(19.9±3.4) μV、(17.2±2.9) μV、(13.7±3.0) μV、(1.3±0.3) μV,均超过对照组的(1.3± 0.3) μV、(20.6±4.4) μV、(17.7±3.3) μV、(14.2±4.1) μV、(11.8±3.4) μV、(1.1±0.3) μV,并且差异均有统计学意义(P<0.05)。而2组产妇耐力肌收缩最大值比较,差异无统计学意义(P>0.05)。 结论旋后肩法用于肩难产产妇助产,较传统耻骨联合上加压法,可改善产妇产后短期内的盆底肌功能。