摘要:

AbstractThe postnatal development of the Sertoli cell barrier, tubular lumen, fluid flow, and cytoskeletal elements in Sertoli and myoid cells was investigated in the Sprague‐Dawley rat. With the aid of hypertonic fixatives, a barrier to the rapid entry of fluid was noted in the majority of tubules on the 15th and 16th postnatal (p.n.) days and was completely formed in all tubules prior to p.n. day 18. The actin forming the ecto‐plasmic specialization (ES), a cytoskeletal complex related to the occluding junctions composing the barrier, began its development during the period of initial barrier formation (16 p.n. day) and progressively attained its adult prominence. The ES developed its characteristic adult pattern and adult fluorescent intensity at about p.n. day 22. Some seminiferous tubules showed very small lu‐mina as early as p.n. day 10. All tubules were not open until p.n. day 30. The size (diameter) of the lumen increased slowly from p.n. day 10 until p.n. day 30 when it started to increase rapidly until about p.n. day 50. Fluid flow in seminiferous tubules was detected as early as p.n. day 20 and increased in amount thereafter. Myoid cell actin filament bundles, running in parallel, were present at p.n. day 10. Actin formed a meshwork pattern characteristic of the adult on, or slightly prior to, p.n. day 22. These data indicate that there is a temporal relationship between the development of the actin cytoskeleton within the Sertoli cell and initial formation of the Sertoli cell barrier. Similarly, there is a temporal relationship between the development of the actin cytoskeleton of myoid cells and tubular fluid flow. The rapid increase in tubular lumen diameter, however, does not correlate with the initial development of Sertoli and myoid cytoskeletal ele

ISSN:0002-9106    

DOI:10.1002/aja.1001840302

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

年代:1989

数据来源: WILEY

摘要:

AbstractCryostat‐and vibratome‐cut sections of rat kidneys were singly or doubly labeled to visualize immunoreactive tyrosine hydroxylase (THI), dopamine beta‐hydroxylase (DBHI), vasoactive intestinal peptide (VIPI), and neuropeptide Y (NPYI). Rats were perfusion fixed with 2‐4% paraformaldehyde with or without 0.15% picric acid and rinsed in buffer for 18‐48 hr. Single antigens were labeled with horseradish per‐oxidase in vibratome sections, whereas cryostat sections were used to label one antigen with perox‐idase and another with a fluorophore in the same tissue section. A dense plexus of DBHI noradren‐ergic nerves innervates the renal arterial tree, and such nerves innervate the interlobar veins and renal calyx as well. Immunoreactive NPY is colocal‐ized in most of these nerves, but some intrarenal noradrenergic nerves do not contain NPY but do contain VIP immunoreactivity. The distribution of NPYI nerves resembles that of DBHI nerves, whereas most perivascular noradrenergic nerves immunoreactive for VIP innervate selected arcuate and interlobular arteries. A small population of nonadrenergic, VIPI nerves innervate

ISSN:0002-9106    

DOI:10.1002/aja.1001840303

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

年代:1989

数据来源: WILEY

摘要:

AbstractThis study describes the hy‐pophyseal angioarchitecture found in 79 adult New Zealand white rabbits. The pituitary glands and attached hypothalami were removed and carefully processed following routine histological methods, and the vascular organization was studied by light microscopy. Whole mounts of the pituitary median eminence complex were prepared and studied with a binocular dissecting microscope employing transmitted and epi‐illumina‐tion.Arterial blood was found to be directed primarily to the neurohypophysis by the superior hy‐pophyseal artery (SHA) and the inferior hypophy‐seal artery (IHA). A direct arterial blood supply was found to the adenohypophysis, but was limited solely to the pars intermedia by branches of the anterior hypophyseal artery (AHA) and the IHA. Capillaries of the pars intermedia were subdivided into an intermediate and a superficial plexus. The superficial plexus was situated between the intermediate plexus and the capillaries of the infundibular process. Capillaries of the superficial plexus did not form anastomoses between themselves, but ramified into the intermediate plexus to form a dense network of anastomosing capillaries that were continuous with capillaries of the pars distalis. A direct arterial blood supply was found only to the superfici

ISSN:0002-9106    

DOI:10.1002/aja.1001840304

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

年代:1989

数据来源: WILEY

摘要:

AbstractAn immunohistochemical and ultrastructural study of human melanoma colonies grown in soft agar for up to 50 days was performed. Three morphological variants of developing tumor colonies are reported: (1) large light colonies, (2) small dark colonies, and (3) smooth‐edged colonies. The large light colony variant is the most frequently observed in the soft agar assay (≈︁70%), followed by the dark colony variant (≈︁27%), and the smooth‐edged colony variant (≈︁3%). Major morphological characteristics are associated with each variant, as shown with light microscopy (LM) and transmission electron microscopy (TEM). Both LM and TEM analyses demonstrated that the large light colony variant was hypomelanotic and contained a microfibrillar extracellular matrix (ECM). The small dark colony variant was found to be hypermelanotic and contained a less demonstrable ECM. The smooth‐edged variant has an encapsulated periphery, no demonstrable ECM, and tightly packed cells with desmosome‐like junctions. In order to characterize further the ECM in the most commonly observed variant, the large light colony, specific antibodies to fibronectin (FN) and collagen types IV and V (COLs IV and V) were applied and observed with immunofluorescence microscopy and immu‐noperoxidase. In paraffin sections of melanoma colonies, FN was observed associated with both the cell surface and the ECM. However, no specific staining was seen for COLs IV and V. In addition, ruthenium red was used to preserve and selectively bind to glycosaminoglycans (GAGs) and proteoglycans (PGs). TEM studies reveal GAG‐like granules stained with ruthenium red in the fibrillar ECM and a dotted, punctate staining of the cell surface. Understanding the biological and architectural composition of developing melanoma tumor colonies in soft agar could contribute to the development of more efficient chemo

ISSN:0002-9106    

DOI:10.1002/aja.1001840305

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

年代:1989

数据来源: WILEY

摘要:

AbstractElectron micrograph composites of tangential sections of the fovea centralis of three cynomolgus monkeys (Macaco, irus) and one baboon (Papio anubis) were used to determine the spatial density of the principal retinal cells. In the center of the foveola, the density of cones ranged from 113,000 to 230,000/mm2, and pigment epithelial cells from 4,900 to 7,000/mm2. At a distance of 500μm from the foveolar center the density of the cone cell pedicles ranged from 29,000 to 36,300/mm2, and the density of horizontal cells ranged from 19,000 to 25,100/mm2. Densities of bipolar, Muller, and amacrine cells were determined in only two monkeys and in the baboon.The fact that the cone cell pedicles have a larger diameter than the foveolar cones explains the geometry of the fovea. The morphology of the junction between foveolar cone outer segments and the pigment epithelium reflects the complex metabolism of this functional unit. The comparison with the peripheral primate retina suggests that the densities of horizontal and bipolar cells, but not of amacrine and Muller cells, are correlated with the density of cone cell pedicles

ISSN:0002-9106    

DOI:10.1002/aja.1001840306

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe endodermal layer of the human yolk sac was examined three‐dimensionally with light microscopy on serial sections using scanning electron microscopy and transmission electron microscopy to find the origin of hemo poiesis in the yolk sac. Cell‐labelling techniques were also employed using the monoclonal anti‐transferrin receptor antibody. Orifices of the endodermal and intracellular tubules facing the yolk‐sac cavity were demonstrated on the endodermal surface. Various‐sized blood cells in various stages of differentiation and maturation were distributed in the yolk‐sac cavity and tubules and were observed also at the orifices of the tubules. The morphological and the immunological findings suggest that blood cells with large nuclei in the endodermal layer are the most immature. The present results suggest that blood cells originate from the endodermal layer and are carried to the embryo through the yolk sac cavity and the vitel‐line duct. It is probable that the endodermal and intracellular systems of tubules have an important role in the transport of blood cells, includi

ISSN:0002-9106    

DOI:10.1002/aja.1001840307

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

年代:1989

数据来源: WILEY

摘要:

AbstractMitochondrial structure has been examined in three dimensions using high‐resolution scanning electron microscopy in cells from rat liver, retina (photoreceptors and retinal pigment epithelium), and kidney (proximal convoluted tubular cells and podocytes). Tissues were prepared by aldehyde‐osmium fixation and freeze cleavage using a cryoprotectant, followed by removal of the cytosol by immersion in a dilute osmium tetroxide solution. The microscope used (Hitachi S‐570) was equipped with a secondary electron detector located in the column above the specimen, situated within the objective lens. Mitochondria in all tissues examined were found to have only tubular cristae, which in some instances could be seen to span the entire diameter of the organelle. The walls of the tubular cristae, when unfractured, were in contact with the inner mito‐chondrial membrane; and their lumens were open to the intermembranous space. We hypothesize that in cells of many, perhaps most tissues, mito‐chondrial cristae are not shelf‐like but are, in fact, tubes which span the mitochondrial matrix and are continuous with the inner mitochondrial membrane a

ISSN:0002-9106    

DOI:10.1002/aja.1001840308

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

年代:1989

数据来源: WILEY

ISSN:0002-9106    

DOI:10.1002/aja.1001840301

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

年代:1989

数据来源: WILEY