Quantitative analysis of myelinated axons of commissural fibers in the rat brain

In this study, the myelinated axons of the rostrum, genu, truncus and splenium parts of the corpus callosum and of the anterior, posterior and habenular commissures were counted in the rat brain by using a camera lucida. The numerical densities of these axons were compared with each other by means of quantitative analytical statistical methods. In parts of the corpus callosum, a statistically significant difference was found between the rostrum and genu, rostrum and truncus, rostrum and the splenium, genu and truncus, and the genu and splenium. However, no statistically significant difference was found between the truncus and splenium. When comparing the number of myelinated axons of the anterior, posterior and habenular commissures, statistically significant differences were found between the anterior and posterior commissures, and between the anterior and habenular commissures. No statistically significant difference was found between the posterior and habenular commissures. Small sized myelinated axons were present in all parts of the corpus callosum and in the anterior commissure. However, a heterogeneous distribution of myelinated axons was present in the posterior and habenular commissures.     

Morphometric Comparison between Controlateral Sciatic Nerves in the Male and Female Rabbit

Some morphometrical parameters of the axons making up the controlateral sciatic nerves, both in the male and female rabbits were calculated and compared by means of a Zeiss Vidas image analyser (Ober Kochen, Germany). The results show that the fibres constituting the left nerve have a greater mean diameter but a lower mean density than those constituting the right nerve. This suggests that the diameter of the myelinated fibres and the density of both the myelinated and unmyelinated fibres do not vary from male to female. On the other hand, the G ratio and the diameter of the unmyelinated axons do, since the nerves on the right side (in both sexes) have higher morphometric values, on average, than the controlateral ones.     

Effects of betamethasone treatment on central myelination in fetal sheep: an electron microscopical study

The long-term effect of betamethasone on the myelination of commissural and associational fibres was investigated in fetal sheep. We studied the corpus callosum and subcortical white matter by electron microscopy. Axons were subdivided into classes according to their axonal diameter: class I: < or =0.65 microm; class II: 0.66-0.84 microm; class III: > or =0.85 microm. Under control conditions, the different functions of the white matter tracts examined were reflected by three morphological criteria: (1) there was a diverse percentage of axonal classes in the investigated areas. In corpus callosum the axons of class II predominate (47.1%). In the subcortical white matter, class I axons with small diameter are in majority (40.8%). (2) In the subcortical white matter more axons are present, with especially large diameter and hence of axonal class III. (3) The axons of subcortical white matter have thicker myelin sheaths than those of the corpus callosum. Betamethasone administration caused a significant decrease of class II axons in the corpus callosum (36.9%). In corpus callosum, axons of all classes present thicker myelin sheaths. Betamethasone administration resulted in a change in the formation of the myelin sheath in the commissural fibres of the corpus callosum but not in the associational fibres of the subcortical white matter. This could be the morphological correlate to behavioral and cognitive changes known to occur in humans after prenatal glucocorticoid treatment.     

新疆塔里木盆地叶城沙蜥的两性异形

叶城沙蜥是一种主要分布于中国新疆南部地区的蜥蜴,通过测量和比较采自新疆塔里木盆地且末县叶城沙蜥的个体大小以及口宽等8个形态特征,研究了叶城沙蜥的两性异形。研究共采集叶城沙蜥62只,其中成年雌性个体27只,雄性个体35只。结果显示:(1)叶城沙蜥雌雄性成体的体长有显著差异,雄性大于雌性,表明叶城沙蜥具有雄性偏大的两性异形模式;(2)叶城沙蜥其他身体形态特征中尾长、腹长和头长3个特征有显著差异,其中雄性的尾长和头长大于雌性,而雌性的腹长大于雄性;(3)叶城沙蜥雌雄性个体间的口宽、眼间距等其他形态特征则没有显著差异。叶城沙蜥的两性异形表现为雄性大于雌性,并且雄性具有更大的头部和更长的尾部,雌性具有更长有腹部,这可能是雄性个体面临的性选择压力与雌性个体面临的繁殖压力共同作用的结果。     

The heritability and genetic correlations of sexual dimorphism for 10-week weight in poultry

The quantitative genetic parameters of sexual dimorphism for 10‐week body weight and its genetic correlation with egg weight and egg number was determined in an unselected population of White Leghorns. The genetic correlation between male and female weights was 0.586 indicating considerable genotype‐sex interaction. The heritability of the difference in weight between males and females was 0.267.

The genetic correlations of the difference in weight between sexes with body weights of males and females were 0.690 and 0.06 respectively. There was evidence of a fairly high positive genetic correlation between egg weight and sexual dimorphism. Egg number to 44 weeks of age and sexual dimorphism were positively correlated but the magnitude of the correlation coefficient was small.     

étude Histomorphométrique des Variations Morphologiques du Follicule Thyroïdien chez le Rat en Fonction de l''âge et du Sexe

The thyroid glands of male and female rats (Sprague Dawley) 10 to 60 weeks of age were examined histomorphometrically. The results show a clear sex dimorphism. The thyroid follicles in the male animals show a greater functional activity than in the female animals. But while the morphology of the follicles in the females was constant throughout the period of observation, in the males the activity gradually diminished.     

促性腺激素抑制激素对SD大鼠性腺生殖功能与糖代谢的影响

【目的】 探究促性腺激素抑制激素（GnIH）对SD大鼠性腺生殖功能和糖代谢的影响,以及SD大鼠性腺生殖功能和糖代谢之间的相关性。【方法】 将36只SD大鼠随机均分为对照组（0.9％生理盐水）、1 μg/100 μL GnIH组（Ⅰ组）、10 μg/100 μL GnIH （Ⅱ组）,每组12只（雌雄各半）。每天07：00和19：00注射生理盐水或GnIH （200 μL/次）,连续注射14 d后测量大鼠体重,计算肥胖程度,麻醉处死后采集卵巢和睾丸,称重并计算卵体比和睾体比;运用阴道涂片法观察雌性大鼠发情周期的变化;显微镜下观察并计算雄性大鼠精子活力;HE染色观察卵巢和睾丸组织变化;用实时荧光定量PCR法检测卵巢和睾丸中糖代谢基因胰岛素受体（IR）、葡萄糖转运蛋白4（GLUT4）和炎症相关因子肿瘤坏死因子（TNF-α）、白介素1β（IL-1β）的表达水平,并用SPSS 22.0软件分析生殖功能和糖代谢之间的相关性。【结果】 与对照组相比,Ⅰ组雌性SD大鼠和Ⅱ组雄性SD大鼠肥胖程度均显著升高（P<0.05）;Ⅱ组卵巢大小/重量、卵体比显著升高,睾丸重量、睾体比显著下降（P<0.05）。HE染色结果显示,与对照组相比,Ⅱ组雌性大鼠卵泡呈囊性扩张,颗粒细胞层减少,卵泡腔变大;Ⅰ、Ⅱ组雄性大鼠的生精小管均出现空泡样改变,生精细胞排列紊乱、层次减少。与对照组相比,Ⅱ组大鼠发情前期的持续时间显著延长（P<0.05）、精子活力显著下降（P<0.05）。实时荧光定量PCR结果显示,与对照组相比,Ⅰ、Ⅱ组雌性大鼠GLUT4基因的表达量极显著下降（P<0.01）、Ⅱ组中IR基因的表达量显著降低（P<0.05）,Ⅰ、Ⅱ组雄性大鼠GLUT4基因的表达量均极显著降低（P<0.01）;Ⅰ组雌性大鼠TNF-α、IL-1β基因和雄性大鼠IL-1β基因的表达量均显著升高（P<0.05）,Ⅱ组雌、雄大鼠TNF-α基因的表达量均极显著升高（P<0.01）。相关性分析结果显示,腹腔注射GnIH后,雌性大鼠的卵体比与GLUT4基因表达水平呈极显著正相关（P<0.01）,与IR基因的表达水平呈显著正相关（P<0.05）;雌性大鼠的发情周期与GLUT4基因表达水平呈极显著负相关（P<0.01）;雄性大鼠睾体比与GLUT4基因表达水平均呈显著正相关（P<0.05）,而精子活力与GLUT4基因表达水平均呈极显著正相关（P<0.01）。【结论】 腹腔注射GnIH能够抑制大鼠的生殖功能和导致糖代谢功能紊乱,而且GnIH可能参与性腺能量代谢与生殖功能的交叉对话,是能量代谢与生殖功能的新型联络因子。     

The influence of sex and gonadectomy on hepatic and brain fatty acid composition,lipogenesis and β‐oxidation

The aim of this study was to investigate the influence of sex and castration of rats on liver and brain fatty acid profile and liver mRNA expression of genes involved in lipogenesis and β‐oxidation. Castration significantly increased body weight and liver index and decreased serum triglyceride content in the female rats. The fatty acid composition of the liver tissue was influenced by sex and castration. Male rats had higher content of C16:0, C18:1n7, C18:2n6 and C22:5n3, while female rats had higher content of C18:0, C20:4n6 and C22:6n3. Castration of male rats decreased differences caused by sex for C18:2n6, C20:4n6 and C22:6n3. Values for C16:1n7 were higher in the castrated male rats in comparison with all other groups. Liver phospholipids showed a distribution of fatty acids similar to the total lipids. Brain total lipids and phospholipids were not influenced by sex or castration. Castration increased ?6D gene expression in both the sexes, while ?5D and ?9D increased in females and males respectively. Gonadectomy increased expression of the FASN gene in the females and decreased CPT1 and ACOX1 gene expression in the liver tissue of male rats. The observed results of lipid peroxidation, measured by TBARS, were the lowest in the intact females in comparison with all other groups. In conclusion, sex strongly influences both SFA and PUFA in liver tissue, and castration decreases these differences only for PUFA. Castration also influences the expression of the genes involved in lipid metabolism differently in male and female rats, with an increase in lipogenic genes in female rats and a decrease in key genes for mitochondrial and peroxisomal β‐oxidation in male rats.     

Genetic analysis of growth curve parameters for male and female chickens resulting from selection on shape of growth curve

The objectives of this research were to evaluate gender differences and selection on body weight as they affect growth curves of chickens. Marginal posterior densities of growth curve parameters were studied by Gibbs sampling on 10,671 male and female chickens originating from five lines. Line X-+ was selected on low body weight at 8 wk (BW8) and high body weight at 36 wk (BW36), line X+- on high BW8 and low BW36, X++ on high BW8 and BW36, X-- on low BW8, and BW36, and X00 was an unselected control line. Growth was modeled by a Gompertz function. Heritabilities and genetic correlations among parameters of the Gompertz curve were estimated. Marginal posterior densities were drawn for parameters of the growth curve and for sexual dimorphism at ages ranging from hatching to 1 yr. Lines selected for a higher BW8 had higher initial specific growth rates (L), higher maturation rates (K), and lower ages at inflection (T(I)). Lines selected for a higher BW36 had higher asymptotic body weights (A). Estimates of A, L, and T(I) were higher in males and K was higher in females. Difference between sexes for A was greater in the line selected for a lower BW8 and a higher BW36. Dimorphism for L and K was the lowest in lines X++ and X--, respectively. The greatest difference in T(I) was observed in the line selected for lower BW8 and BW36. Sexual dimorphism of body weight was lower at most ages in the lightest line. Before 15 wk, sexual dimorphism in X++ line was lower than in the line selected for higher BW8 and lower BW36. The increase in sexual dimorphism with body weight could be reduced by selecting animals on body weight at two ages instead of one, as is usually done in commercial lines.     

约氏乳杆菌对大鼠生长性能、血液指标及脏器指数的影响

本试验旨在研究约氏乳杆菌对大鼠生长性能、血液指标及脏器指数的影响。试验选取SD大鼠80只,雌雄各半。大鼠按照体重相近的原则随机分为4个剂量组,即阴性对照组、试验Ⅰ(5 000 mg/kg体重)、试验Ⅱ(1 000 mg/kg体重)和试验Ⅲ组(200 mg/kg体重)。试验期为30 d。结果表明:试验剂量为200~1 000 mg/kg体重时,约氏乳杆菌对大鼠体增重、总采食量、饲料转化率、血液学指标和病理学指标的影响无显著性差异(P>0.05);试验剂量为5 000 mg/kg体重时,谷草转氨酶、血糖、总胆固醇差异不显著(P>0.05);与其他剂量组相比,大鼠的体增重和总采食量显著降低(P<0.05),但饲料转化率无显著差异(P>0.05);谷丙转氨酶水平显著降低(P<0.05),白蛋白和总蛋白显著增高(P<0.05);雌性大鼠尿素氮和雄性大鼠肌酐显著增高(P<0.05)。综合分析,约氏乳杆菌剂量低于1 000 mg/kg体重时,对大鼠平均日增重、血液指标及脏器指数无影响;约氏乳杆菌剂量高于5 000 mg/kg体重时,对大鼠脏器指数有影响。     

Cranial features of the spotted seal, Phoca largha, in the Nemuro Strait, considering age effects

Cranial features (development, individual variation, and sexual dimorphism) were examined from the 23 metrical characters and 2 nonmetrical characters (the degree of closure of the 9 cranial sutures and the presence of sagittal crest) in the two spotted seal specimen groups at the Nemuro Strait, Hokkaido. One specimen group was incidentally taken in the salmon trap nets between 1982 and 1983 (n = 70), and the other was randomly sampled by damage control kill between 1997 and 1998 (n = 82). The development of morphometrical characters of skulls ceased at 5.6, 10.7, 7.9, and 11.9 yr. old, for 1982-83 male, 1982-83 female, 1997-98 male and 1997-98 female, respectively. The sutures were half ankylosed till approximately 10 yr. old in both sexes. The sagittal crest began from about 5 yr. old in male. Individual variation of skull was large in the feeding, breathing, and facial-expression apparatus. On the other hand, the variation of braincase, and skull concerning to the movement of head/neck tended to be small. Only 1997-98 specimens exhibited a sexual dimorphism in skull characters except for the braincase, whereas the dimorphism was not found in 1982-83 specimens. We could not detect the significant difference between two specimen groups, although there were a few differences in characters related to the rostrum and mandible.     

Agenesis of corpus callosum in calves

Agenesis of the corpus callosum is a rare brain defect in cattle, and was described in two calves. It was characterized by the total absence of the corpus callosum, septum pellucidum and hippocampal commissure. Fornices were present but separated. Both calves also had moderate internal hydrocephalus, micrencephaly and a CSF-filled cyst in the longitudinal fissure dorsal to the thalamus. Clinical signs were not specific. Etiology and pathogenesis are unknown. No evidence of inflammation or inheritance was found as cause of the defect.     

A sensory neuropathy affecting Long-haired Dachshund dogs

A sensory neuropathy affecting three Long-haired Dachshunds is described. The clinical signs were similar and include disturbances of proprioception, pain sensation and urinary function. Sensory nerve conduction was absent in one dog. Nerve biopsy showed a severe depletion of myelinated fibres in sensory nerves and widespread unmyelinated fibre pathology. Clinical and pathological evidence suggests that this axonal neuropathy, which is possibly of inherited origin, affects both myelinated and unmyelinated fibres in sensory and autonomic nerve trunks.     

Altersbezogener Geschlechtsdimorphismus des Nucleus praeopticus medialis hypothalami beim Schwein

The medial preoptic nucleus of the porcine hypothalamus is characterized by an age-dependent sexual dimorphism in the postnatal period of the development. It manifests itself as sexual differences in the density and volume of the perikarya. A transient concentration of perikarya in the centre of the medial preoptic nucleus, especially distinctive in male piglets, is somewhat similar to the ‘sexually dimorphic nucleus of the preoptic area’ of Gorski, as characterized in rats.     

Effects of Hypo‐ and Hyperthyroidism on Proliferation,Angiogenesis, Apoptosis and Expression of COX‐2 in the Corpus Luteum of Female Rats

Although thyroid dysfunction occurs frequently in humans and some animal species, the mechanisms by which hypo‐ and hyperthyroidism affect the corpus luteum have not been thoroughly elucidated. This study evaluated the levels of proliferative activity, angiogenesis, apoptosis and expression of cyclooxygenase‐2 in the corpus luteum of female rats with thyroid dysfunction. These processes may be important in understanding the reproductive changes caused by thyroid dysfunction. A total of 18 adult female rats were divided into three groups (control, hypothyroid and hyperthyroid) with six animals per group. Three months after treatment to induce thyroid dysfunction, the rats were euthanized in the dioestrus phase. The ovaries were collected and immunohistochemically analysed for expression of the cell proliferation marker CDC‐47, vascular endothelial growth factor (VEGF), VEGF receptor Flk‐1 and cyclooxygenase‐2 (COX‐2). Apoptosis was evaluated using the TUNEL assay. Hypothyroidism reduced the intensity and area of COX‐2 expression in the corpus luteum (p < 0.05), while hyperthyroidism did not alter COX‐2 expression in the dioestrus phase. Hypothyroidism significantly reduced the expression of CDC‐47 in endothelial cells and pericytes in the corpus luteum, whereas hyperthyroidism did not induce a detectable change in CDC‐47 expression (p > 0.05). Hypothyroidism reduced the level of apoptosis in luteal cells (p < 0.05) and increased VEGF expression in the corpus luteum. In contrast, hyperthyroidism increased the level of apoptosis in the corpus luteum (p < 0.05). In conclusion, thyroid dysfunction differentially affects the levels of proliferative activity, angiogenesis and apoptosis and COX‐2 expression in the corpus luteum of female rats.     

Structure of the Carotid Sinus of the Dromedary Camel (Camelus dromedarius)

The morphology of the terminal segment of the common carotid artery of the camel was studied. It was found that this artery terminated by giving off a patent internal carotid artery and continuing as the external carotid artery. A presumptive carotid sinus was present at the region of origin of the internal carotid. Similar to that of other mammals, the carotid sinus of the camel was characterized by a comparatively thin vascular wall rich in elastic fibres. With the electron microscope, free (non-encapsulated) afferent endings, efferent endings, encapsulated axons and bundles of unmyelinated and myelinated nerve fibres were found in the wall of the presumptive carotid sinus. The free afferent endings closely resembled baroreceptor endings of the carotid sinus of other mammalian species in their mitochondrial content and the presence of abnormal organelles such as lamellar bodies, vesicular mitochondria and dense bodies. They were regarded as slowly adapting baroreceptors. The presumptive efferent endings were considered adrenergic whereas the encapsulated axons were thought to be the proximal parts of encapsulated sensory nerve endings.     

Sustained hypomyelination and high serum thyroid hormone in aged black tremor hamster

Oligodendrocytes and myelin in the corpus callosum of black tremor and normal hamsters aged over 1.5 years were ultrastructurally examined to determine the myelination index (ratio of myelin thickness/diameter of axon), percentage of naked axons, and proportions of oligodendroglial subtypes (light, medium and dark). The mutant hamsters were remarkably hypomyelinated, with a low myelination index and a high proportion of naked axons, and high proportions of the dark subtypes. Serum concentrations of thyroid hormones (T3 and T4) in 6-week-old mutant hamsters were 2-fold (T3) to 3-fold (T4) higher than those of age-matched normal animals. However, in the aged animals (over 1.5 years old) only T4 levels of the mutant hamsters were higher in the mutant than normal hamsters. The black tremor hamsters were hypomyelinated throughout their life and high serum level of thyroid hormones might have played a role in the hypomyelination.     

豁眼鹅GH基因外显子2多态性与体重和体尺性状的关联分析

实验旨在探究对豁眼鹅体重和体尺性状进行选育的有效分子标记,根据GenBank鹅GH基因的cDNA序列以及前人的研究设计引物,以饲养于辽宁省和江苏省同批出雏的豁眼鹅,共计552只为实验材料,利用PCR-SSCP方法对GH基因外显子2进行SNPs检测,并将纯合基因型进行克隆测序。结果表明:豁眼鹅GH基因外显子2共有2个SNPs突变位点,得到10种基因型AA、BB、CC、DD、AB、AC、AD、BC、BD和CD,等位基因D的频率较高;经χ2检验,公、母鹅群体以及整个群体均处于Hardy-Weinberg平衡状态;将氨基酸序列突变和未突变的基因型分别合并后得到的3种基因型与10周龄体重和体尺性状进行关联分析发现,基因型对体重和部分体尺性状均有极显著(P<0.01)或显著(P<0.05)影响;在公鹅和母鹅群体中,合并后的AB型与BB型分别为高生产性能基因型,可以作为对豁眼鹅体重和体尺性状进行选育的分子标记。     

Age-Dependent Immunolocalization of Fibronectin and Histological Changes in the Thymus of Rats

Age-dependent variations in the immunolocalization of fibronectin (FN) in the thymus were investigated in 1-, 6-, 12- and 20-month-old male and female Swiss albino rats (Rattus rattus) at the light-microscopic level and the changes with ageing in the histological structure of the thymus were also studied. There were no significant differences in the age-dependent variations in the immunolocalization of fibronectin or in the histological structure of the thymus between male and female rats of the same age but there were increases with ageing in the fibronectin content of the thymic capsule, the connective tissue between the lobules, around blood vessels, and in the medulla and cortex of thymus. The connective-tissue content between lobules, fat cells, Hassall's corpuscles, the thickness of capsule and the ratio of the medulla to the cortex of the lobules showed age-dependent increases in the thymus of rats of both sexes. Decreases in the organ weight/body weight ratio were also observed with ageing.     

Effects of mononuclear cell leukemia on altered hepatocellular foci in Fischer 344 rats

Quantitative stereologic analyses were conducted on hematoxylin and eosin-stained liver sections to investigate the potential effects of the presence of mononuclear cell leukemia in Fischer 344 rats on the occurrence of altered hepatocellular foci (AHF). The study consisted of 132 male and 144 female rats taken from control groups at the termination of seven, 2-year National Toxicology Program (NTP) carcinogenicity studies. A minimum of 10 male and 10 female rats were killed at 6, 9, 12, 15, and 18 months into the seven NTP studies to assess progressive development of AHF. At the end of the studies, 43 males and 35 females had histologic evidence of mononuclear cell leukemia in the liver. There were no differences in the morphologic features of AHF between leukemic and non-leukemic rats; however, there was a decreased incidence of clear AHF in both sexes and in basophilic, vacuolated, and mixed-cell AHF in males. Stereologic analysis revealed that there was also a 40 to 73% reduction in the density of basophilic, clear, vacuolated, and mixed-cell AHF in male rats with leukemia and a 31 and 70% reduction in basophilic and clear AHF, respectively, in females with leukemia. The number of eosinophilic AHF was statistically unchanged in both sexes. The eosinophilic AHF, however, were 2.3 times larger and occupied a 4.3-fold greater volume fraction of the liver in leukemic male rats. Changes in the incidence and density of AHF were directly associated with the severity of the leukemia.(ABSTRACT TRUNCATED AT 250 WORDS)