摘要:

AbstractFollowing artificial ulceration of the guinea pig bladder epithelium, study by light microscopy showed that mitotic activity occurs within 24 hours in the basal layer of the remaining epithelium, which leads to thickening, disorganization and cell shedding. At the ulcer margin, the epithelium forms a rolled edge, from the extremity of which a two‐layered sheet of flat cells grows over the edematous ulcer bed, and the ulcer site is protected during dilation of the bladder by localized muscle spasm. Healing is effected within about one week, as the mitotic activity declines. Organization of the new epithelium commences at the periphery and the cells acquire glycogen and alkaline phosphatase. Study by SEM, which included normal bladders, confirmed that new epithelium spreads from a rolled epithelial edge, and also showed that cells undergoing rejection have globular profiles with surface microvilli. The immature epithelial cells are markedly distorted from mutual pressure during migration and their surfaces show only short microvilli. Ulcers heal after four to seven days, depending on size, and the new cells rapidly assume the pentagonal and hexagonal outlines and the reticular pattern of surface ridges, characteristic of mature surface cells. The ridges apparently develop by fusion of rows of microvilli. By the tenth day it is difficult to identify the original ulcer sit

ISSN:0002-9106    

DOI:10.1002/aja.1001500202

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

年代:1977

数据来源: WILEY

摘要:

AbstractUnder scanning electron microscopy (SEM) the surface cells of the guinea pig bladder have pentagonal or hexagonal outlines. Their borders are clearly defined since they are elevated. They possess a large reserve of surface membrane which is markedly folded and wrinkled when the bladder is empty. The folds disappear and the cells become flat during distension. The luminal surface is characterized by numerous reticular ridges which are a remarkably constant feature and persist even under acute artificial distension. A small proportion of the surface cells are small and have less than five sides. Since they show only sparse microvilli as a surface feature, they have a smooth appearance. These are believed to be young surface cells which have just emerged from the intermediate layer, and have not yet acquired the ridged pattern of mature cells.

ISSN:0002-9106    

DOI:10.1002/aja.1001500203

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

年代:1977

数据来源: WILEY

摘要:

AbstractThe existence of a discrete group of cells that are able to phagocytose spermatozoa is reported in the terminal vas deferens of the rat. In addition it is shown that phagocytosis of spermatozoa occurs in the gland of the vas deferens. The cytological mechanisms involved in the phagocytotic process are discussed, and the role that this activity may have on the removal of surplus spermatozoa is discussed.

ISSN:0002-9106    

DOI:10.1002/aja.1001500204

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

年代:1977

数据来源: WILEY

摘要:

AbstractThe reproductive biology ofNoctilio albiventriswas investigated histologically in 112 females collected at the start of their synchronized breeding season during two different sampling years in the Cauca Valley of Colombia. Both ovaries were functional, but the animals were generally observed to be monovular. Embryonic development in the oviduct was found to proceed to blastocyst formation and loss of the zona pellucida. In 22 animals the discarded zona had been left behind in the oviduct upon passage of the embryo into the uterus and was still undissolved at the time of amniogenesis, the latest stage examined. The zonae which had passed into the uterus with the embryos often exhibited signs of dissolution. Most of the early blastocysts were morphologically distinctive, lacking a typical inner cell mass and being instead largely bilaminar. Degenerating ova from previous ovulations were found in the oviducts of two pregnant bats, suggesting thatNoctiliomay be another species in which the embryo stimulates its own escape from the oviduct. During tubal passage of the embryo the secretory cells of the oviductal ampulla and isthmus exhibited a transient engorgement with glycogen, particularly on the side ipsilateral to the new corpus luteum.

ISSN:0002-9106    

DOI:10.1002/aja.1001500205

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

年代:1977

数据来源: WILEY

摘要:

AbstractIn the mouse seminiferous epithelium four sites of formed microtubules (MTS) are axonemes and manchettes of spermatids, Sertoli‐cell cytoplasm, and spindles of dividing cells. Various experimental treatments indicate that the manchette MTS are different from other formed MTS. Fixation in 1% osmium tetroxide yields good preservation of axonemal MTS, varying degrees of preservation of manchette MTS, but no preservation of spindle or Sertoli‐cell MTS. Cell‐suspension, and intact‐tubule cultures subjected to 0–4°C or 50°C exhibit a breakdown of spindle and Sertoli‐cell MTS while manchette and axonemal MTS remain intact. Cell suspensions exposed to Colcemid or colchicine show no MTS in Sertoli and dividing cells; axonemal MTS are unaffected while in the manchette there is an increase in cross‐bridging between MTS. Cell suspensions treated for 120 minutes with vinblastine sulfate do not show MTS in the Sertoli cells, but crystals presumed to be microtubule protein are present after 15 minutes of exposure. Spindle MTS are dismantled but vinblastine‐induced crystals are not present even after 120 minutes of exposure. The manchette MTS are dismantled by vinblastine in a proximal direction from their distal limits. This is accompanied by the formation of crystals of microtubule protein in the spermatid cytoplasm, while axonemal MTS are unaffected. Vinblastine and Colcemid used in combination cause the disruption of Sertoli‐cell MTS after 15 minutes, spindle MTS after 30 minutes and formation of crystals after 60 minutes of exposure. The manchette MTS are disassembled, the pattern is disrupted and increased numbers of cross‐bridges are seen. These findings indicate that the manchette MTS might be intermediate‐type microtubules since they exhibit the reactions of both cytoplasmic

ISSN:0002-9106    

DOI:10.1002/aja.1001500206

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

年代:1977

数据来源: WILEY

摘要:

AbstractThe histogenesis and mechanism of joint clefting of the developing chick embryo up to the fifteenth day of incubation have been studied morphologally, ultrastructurally, and by histochemical methods. Cell degenration was consistently noted 24 hours after differentiation of the joint tissue, and it is postulated that this early cell necrosis might account for the loosening of the medial part of articular mesenchyme (interzone) leading to differentiation of a three‐layered embryonic joint. At the time of joint clefting degenerative cells were also seen in the peripheral parts of the developing articular cavity. In somes cases clefting was immediately preceded and/or accompanied by the appearance of elongated, basophilic and electron‐opaque cells closely arranged along the zone of tissue cleavage. These cells were thought to be implicated in some way in the clefting process and later to constitute a surface cell layer of articular cartilage. In addition to these observations clear morphological and histo‐autoradiographic evidence was found for the presence of an organic component, presumably mucopolysaccharide, in the primitive synovial fluid. Fluid secretion might also account for tissue cleavage at the sites of its accumulation.The data reported here suggest that joint cavity formation results from a combination of both intrinsic, genetically expressed and extrinsic mechanical factors acting synchron

ISSN:0002-9106    

DOI:10.1002/aja.1001500207

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

年代:1977

数据来源: WILEY

摘要:

AbstractThe structure and distribution of elastic tissue were studied in the limiting membrane of the seminiferous tubule from normal human testis. The elastic and elastic‐related fibers (oxytalan and elaunin) were recognized by their tinctorial and ultrastructural characteristics. The connective structures of the limiting membrane, including the fibrotubules and the amorphous material of the elastic system, were studied after tannic acid‐glutaraldehyde fixation. Fibrotubules (oxytalan fibers) were observed in almost all intercellular spaces of the limiting membrane, closely related to the contractile cells; the elaunin fibers (patches of amorphous material surrounded by bundles of fibrotubules) were evident in the outermost layers. The function of this system of elastic tissue and myoid cells is discussed, considering the permeability of the limiting membrane and the role of the myoid cells in the elastogenesis and contractility of the seminiferous tub

ISSN:0002-9106    

DOI:10.1002/aja.1001500208

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

年代:1977

数据来源: WILEY

摘要:

AbstractThe myofibrillar adenosine triphosphatase reaction with acid preincubation allowed the identification of three types of intrafusal fibers in pigeon flexor carpi ulnaris muscle spindles. Measurements of cross‐sectional areas at the polar region showed much overlap in fiber size among populations of each typ

ISSN:0002-9106    

DOI:10.1002/aja.1001500209

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

年代:1977

数据来源: WILEY

ISSN:0002-9106    

DOI:10.1002/aja.1001500201

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

年代:1977

数据来源: WILEY