摘要:

AbstractElectron microscopy of the normal human thymus demonstrates a characteristic vascular‐parenchymal relationship. The vascular lumen is always separated from the thymic parenchyma by: the endothelial cell cytoplasm, a muscular coat in arterioles and veins, the vascular basal lamina, a perivascular space containing collagen fiber and cells, the epithelial‐reticular cell basal lamina and the epithelial‐reticular cell cytoplasm. The width of this perivascular space is proportional to the size of the vessel it surrounds; it is wide around the vessels in the septa and at the cortical‐medullary junction, but narrow around capillaries. While many cells are present in this space around the larger vessels, only collagen is observed around the capillaries. Lymphocytes are the predominant cell type in the space; however, plasma cells, eosinophils, histiocytes, polymorphonuclear leukocytes, mast cells and unidentified granulated cells are also seen.The vascular complex described above may function as a blood‐thymus barrier, as the initial site of exposure of the lymphocytes to circulating antigen and as the route of emigration of lymphocytes from t

ISSN:0003-276X    

DOI:10.1002/ar.1091830402

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe surface epithelium in fetal guinea‐pig ovaries was examined from the time of early sexual differentiation, about 34 days, until approximately ten days before birth.At day 34 the epithelium varied greatly in apperance as seen in the light microscope and possessed a superficial layer of flattened or cuboidal cells. By day 58 the epithelium had changed into one layer of regularly arranged columnar cells. During the same period the number of germinal cells decreased. Connections between the germinal cords and the surface epithelium were observed from day 34, being especially numerous and broad at days 34 and 42 and decreasing in number and size from day 46 onwards. The basement membrane beneath the epithelium gradually increased in thickness.In the electron microscope two types of somatic cells could be distinguished. One type formed a superficial single layer connected by junctional complexes and exhibited intracellular bundles of 60 Å microfilaments running straight through the apical part of the cell, attached to junctional complexes on either side. These bundles were found frequently between days 34 and 42, but were rarely seen after the forty‐sixth day. Microvillous projections into the coelomic cavity were especially numerous from day 34 to day 46.The other type of somatic cells lay in close proximity to the germinal cells: microfilaments or junctional complexes were not observed.The subepithelial basement lamina was continous with that surrounding the connections and the germinal c

ISSN:0003-276X    

DOI:10.1002/ar.1091830403

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

年代:1975

数据来源: WILEY

摘要:

AbstractThis study focuses on the confusion in existing literature concerning the presence of smooth muscle in the capsule and trabeculae of lymphnodes. Human and bovine nodes from several anatomical areas and several individuals of each species were examined by conventional light, electron and fluorescence microscopy. Smooth muscle cells, independent of blood vessels, were demonstrated in the trabeculae and capsules of lymph nodes of both species examined by all three techniques. The need for further study on the function of these cells is indicated.

ISSN:0003-276X    

DOI:10.1002/ar.1091830404

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

年代:1975

数据来源: WILEY

摘要:

AbstractRenewal of the cell populations of the incisor was studied in 100 gm male rats injected with a single dose of3H‐thymidine and sacrificed at various times from one hour to 32 days after injection. Radioautographs showed that a cohort of labeled cells within the enamel organ, odontoblast layer, and pulp was carried passively with the erupting incisor from the apical end toward the gingival margin where the life cycle of these cells was terminated. Labeled cells in the upper and lower incisor, although traversing different absolute lengths, were found in approximately the same functional stage of their life cycle at similar times after the injection. Thus, by one and one‐half days labeled ameloblasts began inner enamel secretion. By 32 days labeled ameloblasts had traversed the entire maturation zone and were located at the gingival margin. Labeled odontoblasts followed closely the movement of labeled ameloblast. The mean rate of ameloblast migration was 567 μm/day on the upper incisor and 651 μm/day on the lower. For the odontoblasts this rate was 500 μm/day (upper) and 631 μm/day (lower). Finally, it was found that as the rat aged, the duration of the life cycle for epithelial and pulp cell populations of the incisor increased because of growth within the longitudinal axis of the tooth. It was concluded that the apical end of the incisor literally “grows backward” in the bony socket, and hence, the duration of the life cycle becomes greater simply because it takes cells longer to physically reach the ging

ISSN:0003-276X    

DOI:10.1002/ar.1091830405

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe study was designed to determine whether or not the rat uterine luminal epithelium exhibits a mitotic circadian rhythm and to ascertain the effect of estrogen treatment at different time periods on the uterine epithelial mitotic response. Immature rats were injected with either sesame oil (controls) or 60 ng of estradiol‐17 β at eight time periods and were necropsied 24 hours after treatment. Colchicine was administered IP two hours before autopsy. Peak mitotic activity was observed during the nocturnal phase (0300) for both the control and estrogen‐treated rats. The nadirs were recorded during the diurnal phase (1800 and 1200 for the control and estrogen groups, respectively). The differences between low and high values were 1100% for the control rhythm and 101% for the estrogen animals. The data demonstrate the existence of overt circadian rhythms in the uterine epithelium for both control and estrogentreated

ISSN:0003-276X    

DOI:10.1002/ar.1091830406

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe trophospongial layer of the near‐term kangaroo rat placenta was examined in the electron microscope. Two ultrastructurally different cellular zones were distinguishable – an inner zone adjacent to the labyrinth and a basal zone located mesometrial to the inner zone. Inner zone cells contained a well developed granular ER and Golgi apparatus as well as polymorphous membrane‐limited granules. The cells also contained modest amounts of glycogen and lipid droplets. Basal zone cells were also rich in ER; some cells had dilated ER cisternae containing a highly structured material which appears as a sheet of hexagons when vieweden face. Basal zone cells may, among other things, function as glycogen storage cells, since they had large cytoplasmic accumulations of glycogen. Unlike the situation in some other rodents, maternal blood draining from the trophospongial layer was always contained in channels lined by a layer of squamous cells which, in turn, was separated from the trophospongial cells by a basal lamina. The trophospongial zones are compared with the trophosngial regions of other rodent placentas and possible functions are consi

ISSN:0003-276X    

DOI:10.1002/ar.1091830407

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

年代:1975

数据来源: WILEY

摘要:

AbstractLumbar and sacral afferent axons in the submucosa of the urinary bladder were recognized by degeneration in seven cats subjected to spinal ganglionectomies. Of 2,935 observed terminating axon profiles, 145 were found degenerating. Lumbar afferent axons were 3.7 times more numerous than sacral afferent axons in the submucosa, a reversal of the ratio reported for the muscle coat of the bladder. Sacral afferent axons were evenly distributed to different regions of the bladder, but lumbar afferents were concentrated in the bladder neck. Apparent endings in the submucosa of the urinary bladder were principally free nerve endings. Synaptic vesicles were found in 57% of observed terminating axon profiles. The bladder neck had more terminating axon profiles of all kinds than other regions of the urinary bladder.

ISSN:0003-276X    

DOI:10.1002/ar.1091830408

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe venous channels responsible for the intracranial drainage were dissected in a series of 25 male and female adult tufted or brown capuchin monkeys (Cebus apella).It was found thatCebushave a venous arrangements fundamentally the same as in man, differing only in that: 1. the monkey has no inferior sagittal sinus, sphenoparietal sinus, and emissary parietal and condylar veins; 2. the occipital sinus is not in connection with other sinuses; 3. there are a sphenopetrosal sinus, a petrosquamous sinus, and an unpaired inferior cerebellar vein; 4. besides the internal jugular vein, there is additional intracranial drainage through the petrosquamous sinus and the postglenoid vein; 5. the superficial middle cerebral vein opens into the petrosquamous sinus; 6. the lingual and facial veins are not tributaries of the internal jugular vein; 7. there is a bilateral uniform division of the superior sagittal sinus at the confluence of the sinuses to drain equally into both transverse sinuses; 8. the vascular pattern appears to be quite stable; anatomical variations appear to be few and unimportant.

ISSN:0003-276X    

DOI:10.1002/ar.1091830409

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe arteries and veins of the fox testis were studied using an angiographic technique. The postnatal development of the testis involved only minor modification of the vasculature. In the non‐breeding season both the arteries and veins of the adult fox testis undergo extensive spiralization which completaly disappears during the breeding season. When the sequence of morphological changes in blood vessels are related to available data on changes in testicular size, blood flow and connective tissue content, it is obvious that the vascular spiralization is passive and related to shrinkage of the organ and does not primarily influence the testicular blood flo

ISSN:0003-276X    

DOI:10.1002/ar.1091830410

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

年代:1975

数据来源: WILEY

ISSN:0003-276X    

DOI:10.1002/ar.1091830401

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

年代:1975

数据来源: WILEY