摘要:

AbstractCushion veins of the human nasal lining were studied in eight patients of both sexes ranging in age from 11 to 59 years. It was found that the subendothelial cushions were part of the tunica media and consisted of smooth muscle cells, collagen and elastic fibers and occasional fibrocytes. The muscle fibers of the cushion nearest to the endothelium were circular. They extended processes towards the endothelium through gaps in the endothelial basement membrane and formed appositional junctions with the endothelial cells. The rest of the cushion consisted of longitudinal muscle fibers. The sarcoplasm of the muscle cells was characterized by large areas filled with vesicles of various sizes. In addition, these cells possessed cytoplasmic processes which were devoid of a basement membrane and which did not show the regular structure of sarcoplasm. The subendothelial cushion possessed a rich, intrinsic nerve supply of adrenergic and cholinergic axons. It is suggested that the cushion veins regulate the drainage of the cavernous tissue and are under nervous and humoral control. The increase in girth of the subendothelial cushion is effected by contraction of the longitudinal muscle cells and probably by uptake of extracellular fluid by means of the specialized cytoplasmic processes. The single layer of circular muscle cells situated between the endothelial lining and the longitudinal musculature, may provide protection to the endothelium against distension when the cushion expands.

ISSN:0003-276X    

DOI:10.1002/ar.1091810102

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe morphology and development of junctional complexes between blastomeres of the preimplantation rabbit embryo were investigated using several approaches. Electron microscopic examination of embryos staineden blocwith uranyl acetate, and the study of junction permeability using horseradish peroxidase and lanthanum nitrate provided information on structure, intermembrane spacing and permeability of the junctional complexes. In addition, the freeze fracture technique was used with day 5 and day 6 blastocysts, since the large size of these embryos facilitated use of this method. These experiments showed that although rudimentary junctions were present between blastomeres of the early cleavage stages, effective tight junctions were not present until the blastocyst stage. Electron microscopic examination of thin sections revealed apical foci of membrane approximation or “fusion” between trophoblast cells by day 4. Freeze fracturing revealed a lattice of interconnecting ridges (on the A face) and grooves (on the B face) in the apical region between trophoblast cells of the day 5 blastocyst. This lattice formed a continuous band along the apical margin of each cell, and therefore constituted a zonula occludens. The zonula occludens of the day 5 blastocyst averaged 2–3 ridges per lattice, while day 6 blastocysts had lattices that averaged 5–6 ridges. Also seen in the freeze fracture replicas from the day 5 and day 6 blastocysts were local accumulations of intramembranous particles on the A face. These particles were often observed in aggregates similar to those of previously described gap junctions. It could not be determined whether these small regions of particles were true gap junctions or a possible primitive form of gap junction because the complementary pitted surfaces (B face pits) were not demon

ISSN:0003-276X    

DOI:10.1002/ar.1091810103

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

年代:1975

数据来源: WILEY

摘要:

AbstractFetal preputial glands from 14‐ to 17‐day old mouse embryos undergo comparable growth, branching, and display similar degrees of cytodifferentiation when cultured in vitro on medium lacking hormones, on this medium in the presence of either of the fetal gonads, and on medium supplemented with testosterone dipropionate. Conversely, morphogenesis of these anlagen is markedly suppressed by estrogen and an anti‐androgen, Cyproterone acetate. These observations demonstrate that acquisition of androgen‐sensitivity is a late event in the morphogenesis of the preputial gland and correlate with the developmental properties of preputial mesenchyme as demonstrated in earlier studies on the epithelio‐mesenchymal in

ISSN:0003-276X    

DOI:10.1002/ar.1091810104

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

年代:1975

数据来源: WILEY

摘要:

AbstractRepair of a fractured membrane bone, the quadratojugal (QJ), has been studied in the newly hatched chick. Complete open fractures never united by bony fusion, even in birds maintained for six months post‐fracture. Extraperiosteal connective tissue invaded the fracture gap and formed thick fibrous bundles which stabilised the fracture. Cartilage of two types formed on these bones. One was derived from periosteal cells and the other from osteoblasts or osteocytes. Considerably more cartilage formed in bones partially fractured than in those completely fractured. The “periosteal” cartilage did not form if the periosteum was removed at the time the bone was fractured. This was because, although the fibrous layer of the periosteum regenerated, the cambial layer did not. Metaplastic cartilage did form in the absence of the periosteum.Isolating fractured bones within polyethylene or glass tubes prevented accumulation of a blastema between the bony fragments. Cartilage did not form in side the tubes but did form where the ends of the tubes abutted onto the bones.Large defects in the bones (4 mm gaps, 4 mm of bone in the place of the QJ) healed via fibrous union with minimal osteogenesis and no chondrogenesis.Severing M. depressor mandibulae at the time the bone was fractured inhibited chondrogenesis, favoured osteogenesis and resulted in development of a pseudarthrosis.The potential for differentiation of the cells of the QJ and the role of adjacent tissues as they related to repair of the fracture was discussed, and the ability of cells from membrane bones to become chondrogenic empha

ISSN:0003-276X    

DOI:10.1002/ar.1091810105

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

年代:1975

数据来源: WILEY

摘要:

AbstractUltrastructural investigation of liver from ten radiothyridectomized adult male albino rats, made hyperthyroid by administration of desiccated thyroid for eight to ten weeks, revealed changes in hepatic organelles, but no differences between centrilobular, midzonal and periportal hepatocytes of a single lobule. The mitochondria were enlarged with an increase in matrix density, but no increase in number of mitochondria or alterations in membranes or criste was observed. The smooth endoplasmic reticulum appeared slightly increased and dilated in treated rats, while stacked cisternae of the rough endoplasmic reticulum were seldom seen. Large vacuoles, which often contained follicular material and frequently opened into the spaces of Disse, were observed at the periphery of hepatocytes. The vacuoles may arise from invaginations of the cell membrane along these spaces to increase the surface area and to act as channels for liver metabolites. Moreover, in hyperthyroid rats hepatic glycogen was uniformly depleted. Whether these changes were a primary effect of thyroid hormone or secondary to metabolic alterations is unclear.

ISSN:0003-276X    

DOI:10.1002/ar.1091810106

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

年代:1975

数据来源: WILEY

摘要:

AbstractVerhoeff's iron hematoxylin (VIH) followed by lead citrate (LC) applied to epoxy thin sections stained the dense component of elastic fibers heavily and the peripheral microfibrillar component lightly in guinea pig trachea and mouse testis fixed with a glutaraldehyde‐osmium tetroxide sequence. This method stained large fimbriated fibers beneath tracheal epithelium, small fibers and stacked aggregates thereof in the deep lamina propria, cartilage and adventitia of the trachea and large stacked fibers in the fibroelastic band of the trachea. Fibers of the fetus differed from those of the adult, especially in the subepithelial elastic lamina of the trachea. Elastic fibers were intimately associated with fibroblasts and particularly slender fibroblast processes in tracheal stroma and with chondrocytes in tracheal cartilage. Fibroblasts associated with elastic fibers in the tracheal subepithelial lamina propria were often closely bordered by eosinophils, mast cells, or monocytes. Occasional mast cells extended slender processes around elastic fibers in the subepithelial lamina propria. In mouse testis and in many regions of the trachea, small elastic fibers were identified which were below the limits of resolution for the light microscope and were not apparent at the ultrastructural level in routinely stained thin section

ISSN:0003-276X    

DOI:10.1002/ar.1091810107

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

年代:1975

数据来源: WILEY

摘要:

AbstractFertilized and unfertilized rabbit ova were exposed to ruthenium red with the zona intact or after machanical removal, for the demonstration of mucopolysaccharides on the surface coat. Ova were also exposed to Concanavalin A. Ruthenium red bound strongly to elements of the zona and increased the opacity of the plasmalemma. There was no notable change in staining of the vitellus following fertilization. Although there were ruthenium red stained bodies resembling cortical granules in crypts in the plasmalemma, there was no evidence for cortical granule extrusion of mucopolysaccharides. The Concanavalin reaction was seen over both unfertilized and fertilized ova, demonstrating receptors for terminal α‐D‐mannopyranosyl, α‐D‐glycopyranosyl, β‐D‐fructofuranyosyl residues. The deposit on the fertilized egg surface was enormously enhanced indicating a change in the distribution of

ISSN:0003-276X    

DOI:10.1002/ar.1091810108

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe effect of 24 and 48 hours' cold stress on the hamsters' adrenomedullary follicles and on the medullary ATPase activity was studied by light and electron microscopy. Only norepinephrine cells were depleted after this stress, and exocytosis seemed to be the mechanism involved in the release of catecholamine. Follicles containing these cells expanded and their lumina became narrow. A few other cellular and follicular changes also occurred and are described.ATPase activity was apparent in control organs along the endothelial linings, in neural elements and macrophages, and in approximately 40% of the linings of follicular lumina. Cold stress did not alter this pattern.These results have been compared with previous findings and the possible functions of the follicular lumina are discussed. It is concluded that they are unlikely sites for catecholamine storage or release.

ISSN:0003-276X    

DOI:10.1002/ar.1091810109

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

年代:1975

数据来源: WILEY

摘要:

AbstractRat anterior pituitaries were cytologically studied following cultivation in organ culture, with and without the addition of hypothalamic and cortical extracts. Although five distinct cell types could be identified with classical stains in the uncultivated glands, the peroxidase‐labeled antibody technique (using antibodies against STH, LTH, FSH, LH and TSH) showed that not all of the immune‐specific cell types were being identified with the classical stains. This discrepancy was magnified following culture as chromophilic cells seen with classic stains decreased in number with an increase in culture time. The peroxidase technique, however, revealed that all cells remained constant in type and number regardless of time in culture. While the addition of either hypothalamic or cortical extract to the culture medium produced cytological alterations demonstrated by the classical dyes, the antibody technique showed no such alterations. Such a comparison of staining techniques emphasizes the hazards of relying solely on histological procedures to reveal the hormonal activity of the pituitary gl

ISSN:0003-276X    

DOI:10.1002/ar.1091810110

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.1091810101

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

年代:1975

数据来源: WILEY