The seminiferous epithelium in the guinea fowl (Numida meleagris)

Summary Spermiogenesis and cellular associations in the seminiferous epithelium of the guinea fowl were studied and described in sexually active adult birds. PAS stain was found to be useful in the recognition of steps of spermatid differentiation only in the first early stages. Nuclear morphological changes were subsequently found to be more reliable in tracing steps of spermiogenesis. It was observed that haematoxylin-eosin stained tissue can be used in the study of spermiogenesis in the bird. Various stages of the seminiferous epithelium were observed in any cross-section of the seminiferous tubules. Distinct cellular associations were observed, but intermix of adjacent germ cells or heterogenous cellular associations were frequently encountered.     

Reproducibility of gastrocnemius medialis muscle architecture during treadmill running

The purpose of this study was to assess the reproducibility of fascicle length (FL) and pennation angle (PA) of gastrocnemius medialis (GM) muscle during running in vivo. Twelve male recreational long distance runners (mean ± SD; age: 24 ± 3 years, mass: 76 ± 7 kg) ran on a treadmill at a speed of 3.0 m/s, wearing their own running shoes, for two different 10 min sessions that were at least 2 days apart. For each test day 10 acceptable trials were recorded. Ankle and knee joint angle data were recorded by a Vicon 624 system with three cameras operating at 120 Hz. B-mode ultrasonography was used to examine fascicle length and pennation angle of gastrocnemius medialis muscle. The ultrasound probe was firmly secured on the muscle belly using a lightweight foam fixation. The results indicated that fascicle length and pennation angle demonstrated high reproducibility values during treadmill running both for within and between test days. The root mean square scores between the repeated waveforms of pennation angle and fascicle length were small (∼2° and ∼3.5 mm, respectively). However, ∼14 trials for pennation angle and ∼9 trials for fascicle length may be required in order to record accurate data from muscle architecture parameters. In conclusion, ultrasound measurements may be highly reproducible during dynamic movements such as treadmill running, provided that a proper fixation is used in order to assure the constant location and orientation of the ultrasound probe throughout the movement.     

Demonstration of extended field-of-view ultrasound’s potential to increase the pool of muscles for which in vivo fascicle length is measurable

Static, B-mode ultrasound is the most common method of measuring fascicle length in vivo. However, most forearm muscles have fascicles that are longer than the field-of-view of traditional ultrasound (T-US). As such, little work has been done to quantify in vivo forearm muscle architecture. The extended field-of-view ultrasound (EFOV-US) method, which fits together a sequence of B-mode images taken from a continuous ultrasound scan, facilitates direct measurements of longer, curved fascicles. Here, we test the validity and reliability of the EFOV-US method for obtaining fascicle lengths in the extensor carpi ulnaris (ECU). Fascicle lengths from images of the ECU captured in vivo with EFOV-US were compared to lengths from a well-established method, T-US. Images were collected in a joint posture that shortens the ECU such that entire fascicle lengths were captured within a single T-US image. Resulting measurements were not significantly different (p = 0.18); a Bland-Altman test demonstrated their agreement. A novice sonographer implemented EFOV-US in a phantom and in vivo on the ECU. The novice sonographer’s measurements from the ultrasound phantom indicate that the combined imaging and analysis method is valid (average error = 2.2 ± 1.3 mm) and the in vivo fascicle length measurements demonstrate excellent reliability (ICC = 0.97). To our knowledge, this is the first study to quantify in vivo fascicle lengths of the ECU using any method. The ability to define a muscle’s architecture in vivo using EFOV-US could lead to improvements in diagnosis, model development, surgery guidance, and rehabilitation techniques.     

贝氏隐孢子虫在珍珠鸡体内发育的扫描电镜观察

采用扫描电镜观察了贝氏隐孢子虫在珍珠鸡体内的发育。大量球形虫体镶嵌于气管和法氏囊微绒毛丛中。气管纤毛消失,微绒毛生发生融合。法氏囊粘膜表面可观察到宿主细胞突起,在突起的表面有数个虫体寄生。滋养体呈球状,平均大小为１．７μｍ。裂殖体拥有４个或８个香蕉状裂殖子。成熟大配子体大小为 ４.２ × ３．３μｍ,在其侧面可观察到锯齿状突起。偶尔能观察到卵囊,其表 面有一明显裂缝。虫体逸出后所留下的带虫空泡似弹坑状,根据其结构可将其分为两类,其中一类为裂殖子或小配子的形成场所,另一类为卵囊的形成场所。     

Gene expression and immunohistochemical localization of megalin in the anterior pituitary gland of helmeted guinea fowl (<Emphasis Type="Italic">Numida meleagris</Emphasis>)

Megalin/the low density lipoprotein receptor-related protein-2 (LRP-2) is expressed in a variety of epithelia and mediates endocytosis of numerous substances. Megalin is also shown to bind clusterin with high affinity. In the pituitary gland, clusterin is localized in endocrine cells, folliculostellate (FS) cells and colloids. The present study examines the expression pattern of megalin within the gland and assesses its cellular localization to that of clusterin so as to deduce their functional implications in colloidal accumulation as relevant in vivo. Quantity of megalin mRNA expression in pituitary and other endocrine tissues was quantified by real-time PCR using SYBR-green I detective system. High levels were detected in kidneys and pituitary. In situ hybridization showed megalin mRNA in FS cells. Megalin protein detected by immunohistochemistry was also observed in FS cells. Immunoelectron microscopy clearly showed the localization of megalin in peripheral region of colloid-containing follicles and on vesicular structures in FS cells. Immunolabeling was also found to be associated with membranes of vacuoles in apoptotic endocrine cells and cell remnants engulfed by FS cells. Double immunofluorescence labeling was performed to determine whether megalin and clusterin in the anterior pituitary were present within the same cell. Simultaneous localization was detected in almost all FS cells surrounding colloids and in several foci of FS cells surrounding endocrine cells. These findings suggest that megalin may drive ingestion of clusterin complexes with products of digested apoptotic endocrine cells in FS cells, and thereby providing a potential mechanism for a receptor mediated uptake of degenerating endocrine cells and secretion of colloid.     

Inevitable joint angular rotation affects muscle architecture during isometric contraction

The purpose of this study was to quantify the influence of inevitable ankle joint motion during an isometric contraction on the measured change of the gastrocnemius medialis muscle (GM) architecture in vivo during the loading and the unloading phase. Sitting on a dynamometer subjects performed isometric maximal voluntary contractions as well as contractions induced by electrostimulation. Synchronous joint angular motion, plantarflexion moment, foot’s centre of pressure and real-time ultrasonography of muscle architecture changes of the GM were obtained. During the contraction the ankle joint position altered and significantly affected the change in muscle architecture. At maximal tendon force (1094 ± 323 N), the measured fascicle length overestimated the change in fascicle length due to the tendon force by 1.53 cm, while the measured pennation angle overestimated the change in pennation angle due to the tendon force by 5.5°. At the same tendon force the measured fascicle length and pennation angle were significantly different between loading and unloading conditions. After correcting the values for the change in ankle joint angle no differences between the loading and the unloading phase at the same tendon force were found. Concerning the estimation of GM fascicle length–force and pennation angle–force curves during the loading and unloading phase of an isometric contraction, these findings indicate that not accounting for ankle joint motion will produce unreliable results.     

FMMU白化豚鼠线粒体DNA RFLP分析研究

目的研究FMMU白化豚鼠的mtDNA,并与花色豚鼠mtDNA进行多态性分析比较,以确定其独特的生物学特性是否与mtDNA相关。方法用碱变性法提取FMMU白化豚鼠以及花色豚鼠的mtDNA,并用AvaⅠ、BalⅠ等12种限制性内切酶进行酶切和限制性片段长度多态性分析。结果与结论FMMU白化豚鼠mtDNA和花色豚鼠mtDNA的相对分子质量相同,约为16.7×103;FMMU白化豚鼠与花色豚鼠两品系的mtDNA经AvaⅠ、BalⅠ等内切酶酶切后有3-8个酶切位点,酶切图谱完全相同,经RFLP分析FMMU白化豚鼠与花色豚鼠的mtDNA之间缺乏多态性。本实验没有发现FMMU白化豚鼠的独特的生物学特性与mtDNA相关。     

中国家鸡的起源探讨

测定了6个家鸡品种30个个体的线粒体D0环区539bp的碱基序列,并与GenBank中的红原鸡、灰原鸡、绿原鸡、黑尾原鸡及鹌鹑的相应序列作比较分析,构建了分析系统树。结果表明,原鸡属4个种间差异较大,其中家鸡与泰国及邻近地区红原鸡关系最近,与印尼红原鸡、黑尾原鸡、灰原鸡、绿原鸡及鹌鹑的关系依次变远。提示中国家鸡可能起源于泰国及邻近地区的红原鸡。结果还显示,该原鸡的两个亚种（G.g.gallus和G.g.spadiceus)间的遗传分化程度显著低于家鸡亚种内的分化程度,这两个亚种似乎可以归为同一亚种。