摘要:

AbstractThis sequence of electron micrographs shows the progressive changes undergone by the dispersed chromosomal fibrils of the interphase nucleus as they begin to condense, in early prophase, into clumps centered on three types of small nuclear structures. These bodies do not seem to have been described previously in detail in connection with mitosis, although they were mentioned as a group in a preliminary note by Bloom (1963). In the present report they are divided into three groups indicated as F1, F2and F3and are labelled 1, 2 or 3 in the accompanying electron micrographs.The clumps enlarge by continued accretion of more and more fibrils concentrated about these three types of bodies until the chromosomes of metaphase are formed. The inference that the bodies depicted here form focal points for the condensation of dispersed chromosomal filaments rests solely on the repeated finding of the progressive aggregation of the fibrils about them. Further studies are in progress on factors mediating these changes and on the nature of the F bodies.

ISSN:0003-276X    

DOI:10.1002/ar.1091670302

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

年代:1970

数据来源: WILEY

摘要:

AbstractThe alveolar macrophage of the cat shares some features with the alveolar macrophages of ordinary laboratory mammals and man, mainly a voluminous Golgi zone exhibiting evidence of secretory activity. The very numerous typical lysosomes appear to be a secretory end product. They increase in size by a fusion process. At some stage of this process dense periodic structures, crystal‐like, become visible in intermediate size lysosomes, which later form heterogeneous crystal‐like granules characteristic of the cat's alveolar macrophage.The crystal‐like granules are bounded by a unit‐membrane pattern and contain a dense periodic parallel lamellar material (crystal‐like) mixed with fluffy amorphous substance and surrounded by a clear homogeneous material. Based on its structure as observed at a high magnification, and its behavior during phagocytosis, this crystal‐like material appears to be composed of lipid.Intra‐pulmonary injection of red blood cells was carried out in order to observe the fate of the crystal‐like granules during phagocytosis as compared to that of typical lysosomes. Like typical lysosomes the crystal‐like granules become reduced in number and undergo incorporation to the phagocytic vacuoles, demonstrating their

ISSN:0003-276X    

DOI:10.1002/ar.1091670303

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

年代:1970

数据来源: WILEY

摘要:

AbstractA relatively well developed prostrate is the only accessory sex gland present in the spotted skunk (Spilogale putorius). The distal end of the vas deferens is quite glandular, but there is no distinct ampullary swelling. The gross morphology of this species is compared with that of several other members of the family Mustelidae.

ISSN:0003-276X    

DOI:10.1002/ar.1091670304

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

年代:1970

数据来源: WILEY

摘要:

AbstractMicrotubules have been described to occur frequently within the subpial fibrous astrocytes of the adult spinal cord of three species. This finding is related directly to perfusion fixation by glutaraldehyde. Immersion fixation produced no or fewer tubules in this area. It is suggested that the presence of microtubules in these cells might reflect a specific skeletal function. Astrocytes from other locations within the central nervous system displayed fewer microtubules within their cytoplasm.

ISSN:0003-276X    

DOI:10.1002/ar.1091670305

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

年代:1970

数据来源: WILEY

摘要:

AbstractLight and electron microscopy of the carotid body of the Weddell seal shows two types of cells, the main and the sustentacular cells.The main cells contain dense osmiophilic granules in variable amount. Their cytoplasma shows either a high or a low electron density. On this basis light and dark main cells were distinguished.The differences in cytoplasm electron density and the great variability in the number of granules were interpreted as expressions of different stages in a process of secretory nature.A very rich innervation with outstanding nerve endings was observed in the carotid body of the Weddell seal. This picture is similar to that observed in stimulated carotid bodies. The carotid body of the Weddell seal a marine mammal that stays underwater for a long stretch of time, may be considered as subjected to frequent stimulations.

ISSN:0003-276X    

DOI:10.1002/ar.1091670306

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

年代:1970

数据来源: WILEY

摘要:

AbstractThe fine structure of the smallest branches of the hepatic arterial system of the rat was studied with the light and electron microscope by means of alternate thick and thin serial sections.The terminal arborizations of the hepatic artery closely follow the pattern of the portal vein and give rise to a dense network of capillaries in the periportal connective tissue which closely surrounds the bile ducts. These periductal capillaries end by joining (a) interlobular veins, (b) terminal distributing veins, (c) sinusoids directly or, (d) sinusoids in common with branches of the portal vein. The capillaries arising from larger arterioles have well developed precapillary sphincters at their origins, while those arising from terminal arterioles have less prominent smooth muscle cuffs. There are no smooth muscle sphincters at the terminal ends of the capillaries where they join branches of the portal vein or sinusoids. Large endothelial cells usually guard these junctions and frequently their nuclei bulge into the lumens of the vessels and may close them off. Occasionally unmyelinated nerves with vesicles about 500 Å in diameter, some of which are granulated, are in close proximity to the endothelial cells of the capillaries. Endothelial cells also guard the beginnings of sinusoids originating from the portal vein. The sinusoids arising from periductal capillaries are identical in structure to those directly off from the portal vein. Initially the sinusoids from both types of vessels are like capillaries, with a continuous basement membrane around them and an unfenestrated endothelium. A short distance into the parenchyma they lose their basement membrane, become fenestrated and are typical sinusoids

ISSN:0003-276X    

DOI:10.1002/ar.1091670307

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

年代:1970

数据来源: WILEY

摘要:

AbstractA light and electron microscopy study of the structure of the pronephros of the carp,Cyprinus carpio, revealed lymphocytopoiesis, plasmacytopoiesis and erythrocytopoiesis. In addition to the lymphocytes of various sizes, there were transitional cells which had characteristics of both lymphocytes and plasma cells. Some of the plasmacytoid cells had a configuration of cytoplasmic granules suggestive of the Russell body formation described in higher mammalian forms. When India ink particles were injected into the fish intraperitoneally, macrophages containing this marker could be found in the pronephros. The highly vascular structure of this organ emphasized the close association of the cellular elements with the circulating blood. In view of the cell population of the pronephros and its role as a major source of cells producing antibody, it may well represent a primitive prototype of the more advanced mammalian lymph node.

ISSN:0003-276X    

DOI:10.1002/ar.1091670308

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

年代:1970

数据来源: WILEY

摘要:

AbstractPreviously it has been shown that wounds made on the backs of female C57BL/6J mice result in the stimulation of growth of resting hair follicles surrounding the wound. Since aging is known to affect regenerative processes, the question arises if aging affects the stimulation of hair growth in wound healing.Surgical wounds 5mm in length were made on the backs of female C57BL/6J mice between 367–544 days of age. Mice were examined daily for the stimulation of hair growth around the wound, as well as the amount of hair growth stimulation.Damage results in the stimulation of growth of the resting hair follicles surrounding the wound. Hair growth stimulation is first grossly evident 20 days after wounding. This is not significantly different from the time hair growth stimulation appears in young female mice.Aging results, however, in a significant decrease in the amount of hair growth stimulation surrounding the wounds in female mic

ISSN:0003-276X    

DOI:10.1002/ar.1091670309

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

年代:1970

数据来源: WILEY

ISSN:0003-276X    

DOI:10.1002/ar.1091670301

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

年代:1970

数据来源: WILEY