Time course of the regeneration of the endplate zone after autologous muscle transplantation

Reinnervation of transplanted muscles occurs in 2 steps. During the first 5 months the motor axon terminals innervate primarily the border of the original endplate zone, re-establishing its previous outline. In the next 4 months, by further ramifying of the axons, new nerve-muscle contacts are formed exclusively within the boundaries of this zone.     

The evolution of a trading zone: a case study of the turtle excluder device

This paper explores the evolution of a trading zone by organizing the case study of turtle excluder devices within the model proposed by Collins et al. (2007). The case study offers evidence that trading zones do evolve and that the concepts of enforced and fractionated trading zones hold practical utility for describing and defining the complexities of actual exchanges. In this case a trading zone evolved from enforced to fractionated and ultimately diverged into two trading zones. For each step of the evolution I describe the forces that drove these transitions. Finally, I present an adapted trading zone model that is conceptually a better fit for the turtle excluder device case study.     

Autoradiographic study of a bacterial colony. Application to the effects of polymyxin on Pseudomonas aeruginosa colonies]

The autoradiograph of a colony of Ps. a. which has been transferred, during growth, on a medium added with polymyxin and tritiate leucin makes it possible to locate an upper zone with a high metabolic activity and a basal zone with no metabolic activity. The latter, which consists of lysed cells, acts probably as a selective filter against the drug.     

Involutive morphological modifications in the rat adrenal glomerular zone after a low-sodium diet

Summary We have studied glomerular zone involution in the rat's adrenal gland after a period of hyperfunction brought about by a low-sodium diet. The changes observed in this zone affect those organoids that are more directly involved in steroid genesis; mitochondria, smooth endoplasmic reticulum and liposomes. The Golgi complexes appear very developed, often, showing, a positive acid phosphatase activity. Lysosomes suffered a considerable increase in their number, and carried out their digestive function on liposomes. All those changes discussed here are seen as an accomodation of this zone to the new normofunctional situation.     

Coated vesicles in the rat adrenal glomerular zone after a low-sodium diet

Summary In rats subjected to a low-sodium diet, a great activity was observed of the coated vesicles at Golgi complex and cell surfaces of glomerular adrenal zone. These findings are related to the function of these organoids in the uptake and transport of necessary substances under stimulating conditions of the zone.     

Coated vesicles in the rat adrenal glomerular zone after a low-sodium diet.

In rats subjected to a low-sodium diet, a great activity was observed of the coated vesicles at Golgi complex and cell surfaces of glomerular adrenal zone. These findings are related to the function of these organoids in the uptake and transport of necessary substances under stimulating conditions of the zone.     

国际临界带研究发展回顾与美国临界带研究进展介绍

基于对临界带国际发展态势的分析,梳理了临界带的概念;回顾了国际临界带研究的发展历程;并重点对美国在临界带研究方面的进展及其已经部署的6个临界带观测站进行了详细的介绍。     

三峡库区消落带分区固土护岸模式

三峡库区消落带是库区陆域与水库之间生态过渡的缓冲带,在生态系统中发挥着极重要的作用,也是生态系统极度脆弱的地区之一。保护三峡水库,使三峡工程有效运转,是该地区生态环境保护的当务之急。本文以消落带为研究对象,依据消落带功能及生态环境特点,论述了植被恢复与重建对消落带固土护岸的重要性,总结了固土护岸的植被技术及其与小型工程措施相结合的治理方法,并因地制宜地提出了消落带分区固土护岸模式,以期促进该模式的推广和应用,从而为长江三峡库区消落带的生态恢复与重建提供经验及技术支撑。     

Effect of ultrasonic waves on the ribonuclease activity

Résumé L'irradiation ultrasonique de racines deLens culinaris provoque une baisse de l'activité RNasique dans la zone apicale (0–5 mm). L'ultrason étant non-cavitant, cette réduction d'activité doit être causée par l'action dénaturante liée aux effets thermiques de la perturbation ultrasonique. La relativement haute viscosité cytoplasmique de la zone apicale expliquerait pourquoi celleci est la seule à être affectée.     

Tracts of putative ultraviolet receptors in the retina of the two-year-old brown trout (Salmo trutta) and the Atlantic salmon (Salmo salar)

We previously showed that the brown trout possesses UV-sensitive cones in its retina that are lost in 2-year-old fish. However, present investigations reveal that in the narrow growth zone along the periphery and the ventral embryonic fissure, the formation of these cones continues in trout and salmon.     

Migratory patterns of clonally related cells in the developing central nervous system

Neurons and glioblasts that arise in the ventricular zone migrate to form discrete nuclei and laminae as the central nervous system develops. By stably labeling precursor cells in the ventricular zone, pathways taken by different cells within an individual clone can be described. We have used recombinant retroviruses to label precursor cells with a heritable marker, the E. coli lacZ gene; clones of lacZ-positive cells are later mapped histochemically. Here we review results from three regions of the chicken central nervous system--the optic tectum, spinal cord, and forebrain--and compare them with previous results from mammalian cortex and other regions of the vertebrate CNS. In particular, we consider the relationship between migratory patterns and functional organization, the existence of multiple cellular sources of migratory guidance, and the issue of whether a cell's choice of migratory pathway influences its ultimate phenotype.     

Immunohistochemical demonstration of corticotrophic cells concentrated in the rostral zone of the pars intermedia of the mouse hypophysis

Résumé La nature corticotrope des cellules constituant la partie rostrale de la pars intermedia de l'hypophyse de souris est établie par la microscopie électronique et la cytoimmunofluorescence. Cette zone réagit positivement avec les anticorps anti-ACTH et négativement avec les anticorps anti-MSH.     

Migratory patterns of clonally related cells in the developing central nervous system

Summary Neurons and glioblasts that arise in the ventricular zone migrate to form discrete nuclei and laminae as the central nervous system develops. By stably labeling precursor cells in the ventricular zone, pathways taken by different cells within an individual clone can be described. We have used recombinant retroviruses to label precursor cells with a heritable marker, theE. coli lacZ gene; clones of lacZ-positive cells are later mapped histochemically. Here we review results from three regions of the chicken central nervous system — the optic tectum, spinal cord, and forebrain - and compare them with previous results from mammalian cortex and other regions of the vertebrate CNS. In particular, we consider the relationship between migratory patterns and functional organization, the existence of multiple cellular sources of migratory guidance, and the issue of whether a cell's choice of migratory pathway influences its ultimate phenotype.     

Galactose intoxication pathologic study in the chick

Résumé Des poussins nourris avec une ration contenant plus de 10% de galactose développent des tremblements, des convulsions et meurent. Une dégénération des neurons et de l'oedéma péri-cellulaire se présente dans la zone des ganglions basals, dans la zone médullaire et dans les lobes optiques.

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Supported by grant B 2951 (C1) from the National Institute of Neurological Diseases and Blindness, National Institutes of Health, United States Public Health Service.     

The relationship of the vertical distribution of Japanese conifers to the maltol contents in their leaves

Summary Of 35 species of coniferous trees in Japan, only 4 species, found at subalpine zone, contain maltol in their leaves. Their leaves are also characteristic for their high content of sugar which protects the plants against freezing. It is interesting from the viewpoint of plant ecology that only the above 4 species contain high amounts of sugars and maltol in their leaves because maltol is biosynthesized from sugars.     

Migration intercinétique dans la placode olfactive chez l'embryon de poulet interkinetic nuclear migration in nasal placode

Summary Cells of nasal placode of chick embryos were studied with thymidine H³ and autoradiography. Our results shown, that the nuclei in the nasal placode synthesize DNA in the outer zone, then migrate toward the inner zone to undergo division and subsequently return to the outer zone.     

Simple technic for culture of locus coeruleus nucleus in the newborn mouse]

The dissecting procedure and tissue culture technique on collagen coated coverslips in Leighton tubes, of newborn Mouse nucleus locus coeruleus and the regular histofluorescence demonstration of catecholaminergic fibers in the outgrowth zone are described. This simple method allows 10 day--long experiments .     

Injury-induced neurogenesis in the mammalian forebrain

It has been accepted that new neurons are added to the olfactory bulb and the hippocampal dentate gyrus throughout life in the healthy adult mammalian brain. Recent studies have clarified that brain insult raises the proliferation of neural stem cells/neural progenitor cells existing in the subventricular zone and the subgranular zone, which become sources of new neurons for the olfactory bulb and the dentate gyrus, respectively. Interestingly, convincing data has shown that brain insult invokes neurogenesis in various brain regions, such as the hippocampal cornu ammonis region, striatum, and cortex. These reports suggest that neural stem cells/neural progenitor cells, which can be activated by brain injury, might be broadly located in the adult brain or that new neurons may migrate widely from the neurogenic regions. This review focuses on brain insult-induced neurogenesis in the mammalian forebrain, especially in the neocortex.     

Impulse propagation from the SA-node to the ventricles

Summary Normally the pacemaker of the mammalian heart is located in the sinus node. In the rabbit the sinus node can be subdivided into two regions, the center of the node where the impulse originates and the border zone through which the impulse is conducted towards the atrium. Conduction properties of both regions were investigated. It appeared that conduction velocity increases and refractoriness decreases when one goes from the nodal center towards the atrium. The tissue mass of the atrium is large in comparison to the sinus node and normally the resting membrane potential of atrial fibers is more negative than that of nodal fibers; consequently, a potential difference exists causing a current flow between both areas. Evidently this hyperpolarizing current flow depresses impulse formation in the border zone fibers which have better intrinsic pacemaker properties than fibers in the nodal center. If the impulse has reached the atrium it is conducted with a relatively high safety factor and will reach the AV node in principle without difficulty. The AV node, if deprived of sinus nodal dominance, develops spontaneous activity originating from the lower nodal fibers. Also in this structure, electrotonic depression by surrounding tissue causes deceleration of the pacemaker.     

Thixotropic effect and electro-osmosis as possible factors of membrane electrical excitability]

Cation motion under the electrical field might break the membrane structure. In the temporary wake of each cation conductivity would be increased. Thus a zone of negative resistance would occur in the intensity-voltage relation. Membrane dehydration, due to electro-osmosis, might induce repeated flip-flops of current at the limits of the negative resistance zone.