摘要:

AbstractThis study reports an electron microscopic investigation to the spinal meninges of the rat as they exist between the dorsal and ventral nerve roots in upper thoracic and cervical levels of the vertebral column. Between these roots, at a point where they penetrate the spinal dura, the leptomeninges are characterized by a histological pattern comparable to that elsewhere comprising the subarachnoid angle. However, this region is modified and possesses a number of heretofore unknown histological features. The most noteworthy is alateral recessof the subarachnoid space.The meninges located between the nerve roots do not form a definite lateral boundary for the subarachnoid space. Here the subarachnoid space opens into a lateral recess which extends peripherally between the dorsal and ventral nerve roots. Conspicuous amounts of cellular debris are collected within the lateral recess. Numerous free macrophages congregate here. The lateral recess may be a communicating pathway between the central and peripheral nervous systems by way of the endoneurium of the nerve trunk.

ISSN:0003-276X    

DOI:10.1002/ar.1091710102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

摘要:

AbstractMouse oocytes obtained at various times after administration of HCG or after culture were studied with the electron microscope. Gradual changes were observed in the perivitelline space, plasma membrane and cortical cytoplasm. Disappearance of the regular microvilli, the formation of lamellae‐like processes and vesicular bodies were observed. A progressive increase in the number of cortical granules and multivesicular complexes was observed simultaneously with the disappearance of the rough endoplasmic reticulum. In general, eggs which were matured eitherin vivoorin vitroshowed similar patterns of morphological differentiation. Degenerative changes were seen in most eggs cultured for 17 hours, but not for nine hours or less. In aged tubal eggs recovered at 26 and 36 hours after injection of HCG, the number of cortical granules was decreased relative to previous stages and their extrusion from the egg was apparent. The fertilizability of the eggs maturedin vitroand the role of the cortical granules are discussed in terms of the reaction of the zona pellucid

ISSN:0003-276X    

DOI:10.1002/ar.1091710103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

摘要:

AbstractExplants of the embryonic rat palate have been treated by adding sodium fluoride and sodium pyruvate to the culture medium. Fluoride, at specific concentrations, causes retardation of palatal shelf growth so that fusion does not occur during the culture period. Partial or complete fusion does occur if fluoride levels are reduced.Sodium pyruvate added to the medium advances the time of fusion of explants over that found in controls. When combined with fluoride in the medium, pyruvate can reverse the effects of fluoride on shelf growth and permit complete fusion to take place in a laige percentage of explants.The mode of action of flucride or pyruvate under these experimental conditions has not been determined. However, the known effects of fluoride as an enzyme inhibitor must be considered.

ISSN:0003-276X    

DOI:10.1002/ar.1091710104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

摘要:

AbstractTissue cultures of fetal rat adrenals were used to study effects of cycloheximide on the ACTH‐induced synthesis of mitochondrial inner membranes in the cortical cells. Cycloheximide alone added to the culture medium in concentrations of 100‐0.25 μg/ml killed the cortical cells during six days of treatment. At the dosage level of 0.15 μg/ml/6 days, it induced a decrease in the size of mitochondria and an increase in the pleomorphism of mitochondria. Cycloheximide at a concentration of 0.015 μg/ml/6 days induced no change in the ultrastructure of cortical cells. When cycloheximide in concentrations of 0.15 μg/ml/6 days was added to the culture medium together with 100 mU/ml/6 days of ACTH, the ACTH‐induced changes of mitochondrial inner membranes (formation of 600 Å vesicles) was completely inhibited. It also suppressed the ACTH‐induced development of smooth surfaced endoplasmic reticulum, hypertrophy of Golgi apparatus, development of microvilli and accumulation of lipids. However, it had no effects on the ACTH‐induced increase in the number of polysomes 01 the increase of heterochromatin in the nucleus. Cycloheximide (0.08 μg/ml/6 days) given together with 100 mU/ml/6 days of ACTH had incomplete inhibitory effects on the ACTH‐induced differentiation of the cortical cells. Cycloheximide (0.015 μg/ml/6 days) given together with ACTH resulted in only slight inhibition of ACTH‐induced ultrastructural differentiation of adrenal cortical cellsin vitro.The present observations suggest that (1) the stimulatory effect of ACTH on mitochondrial protein synthesis is dependent upon nuclear control of protein synthesis; (2) a specific cytoplasmic mitochondrial protein synthesis stimulating factor in the cytoplasm of cortical cells is dependent on ribosomal protein synthesis and is a mediator of ACTH action on the mitochondrion; (3) despite their apparent autonomy, the mitochondria in cortical cells are kept under nuclear control; (4) the only direct locus for the trophic effect of AC

ISSN:0003-276X    

DOI:10.1002/ar.1091710105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

摘要:

AbstractThe typical thyroid epithelium of the cream variant of the Syrian hamster differs from that of other common mammalian species. One obvious difference noted by light microscopy is that the cells contain numerous PAS‐positive granules apical to the nucleus. By electron microscopy these granules are dense granules resembling lysosomes. The cells have exceptionally long microvill and numerous junctions and interdigitations of lateral plasma membranes with those of their neighbors. Many organelles in the cells are stratified rather than arranged at random. In addition to the dense granules and centrioles, the Golgi apparatus is usually located at the level of the apical end of the nucleus. The granular reticulum is primarily in the basal half of the cell, although some is apical. Microtubules are especially abundant and are located ainly close to the lateral surfaces and around the nucleus, although some are near apical or basal plasma membranes. The microtubules frequently appear to be in contact with mitochondria and dense granules, but their role in the positioning or stratification of organelles is uncertai

ISSN:0003-276X    

DOI:10.1002/ar.1091710106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

摘要:

AbstractThe intracranial epiphysis of the adult frog,Rana pipiens, has been examined by electron microscopic cytochemistry and radioautography. Acid phosphatase is localized within vacuoles of macrophages free in the lumen, in subspherical vesicles of the ellipsoid portions of photoreceptive cell inner segments, and in occasional heterogeneous cytoplasmic inclusions of the supportive cells.The distribution of radioactivity in the epiphysis at intervals of 1, 3, 5, 9, 14, 25, and 60 days following injection of tritiated leucine, as determined by quantitative radioautography, is consistent with an hypothesized process of continual renewal of photoreceptive cell outer segments. The pattern of radioautographic labeling of the pineal photoreceptors, which resembles more closely that of retinal cones than rods, is correlated with previous morphologic and electrophysiological studies of these cells.The radioautographic and cytochemical data suggest that macrophages within the epiphyseal lumen are involved in phagocytosis and, ultimately, in digestion of degenerate outer segments. They may perform a function similar to that of pigment epithelial cells of the lateral eye retina.

ISSN:0003-276X    

DOI:10.1002/ar.1091710107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

ISSN:0003-276X    

DOI:10.1002/ar.1091710108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

ISSN:0003-276X    

DOI:10.1002/ar.1091710109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

ISSN:0003-276X    

DOI:10.1002/ar.1091710101

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY