bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes in histochemical distribution of cell surface heparan sulfate proteoglycan in mouse uterus during the estrous cycle and early pregnancy
Authors: Potter Sandra W. , Morris John E. 
Published: February 2005

AbstractWe have investigated the changes in immunolocalization of a cell surface heparan sulfate proteoglycan (HSPG) in the mouse uterus during the estrous cycle and at the time of implantation in early pregnancy. A monoclonal antibody prepared against syndecan, a cell surface HSPG from mouse mammary epithelium (gift of Dr. M. Bernfield), was reacted with unfixed and fixed frozen sections of uteri from normally cycling, 3.5 and 4.5 days pregnant, and estradiol‐treated immature and ovariectomized mature mice. A polyclonal antibody prepared against basal lamina HSPG from Engelbreth‐Holm‐Swarm (EHS) tumor cells (gift of Dr. John Hassell) was used as a positive control. The latter showed no variation during the estrous cycle or early pregnancy. Localization of syndecan in uterine epithelium changed from basolateral to predominantly basal as the cycle progressed from metestrus toward estrus. A similar pattern was seen in immature and ovariectomized mature females that had received estradiol injections. With the onset of pregnancy, the basolateral localization became progressively less intense from 3.5 days through 4.5 days of pregnancy. Thus, cell surface HSPG distribution is modulated by hormonally dependent changes in cycling and pregnant mice, supporting previous suggestions that early pregnancy in mice is accompanied by a turnover and rearrangement of uterine epithelial cell surface.© Willey‐Liss, Inc.
Scanning electron microscopy of developing primary endoderm during first 6 hours of incubation in the chick
Authors: Low Frank N. , McClugage Sam G. 
Published: February 2005

AbstractDevelopment of primary endoderm in the domestic fowl (Gallus domesticus) is described in scanning electron microscopy (SEM) supplemented by transmission electron microscopy (TEM). Although complicated by great variability, the ventral surface of the blastoderm reveals this process during the first 6 hours of incubation. Primary endoderm arises (1) from the hypoblast, (2) from the margin of the area pellucida, and (3) from intervening protions of the area pellucida. The early hypoblast becomes several cells thick while individual cells are still spherical. TEM reveals a variety of immature cell junctions. During subsequent flattening of these cells into primary endodermal epithelium, numerous filopodia arise from their surfaces. These are 0.20–0.25 μm in diameter. They become long and branched, attaching to each other and to other cell bodies. Similar filopodial processes are present less conspicuously among cells in the margin of the area pellucida. Here, there is pseudopodial evidence that cells or cell sheets creep along the ventral surface of the epiblast. The filopodia disappear as cell flattening proceeds. The ventral surface of the exposed epiblast delaminates cells that become free after their exploratory filopodia and lamellipodia are put forth. Lateral contacts among cell bodies from the above three sources increase until a continuous epithelium is formed. The primary endoderm of the embryo, a simple squamous epithelium that separates the connective tissue space above from the gastrocoele below, is generated by these developmental events. © Wiley‐Liss, Inc.
Vasocontractions of the in‐vitro toad aortas induced by endothelin‐1 and sarafotoxin‐S6b
Authors: Doi Yoshiaki , Fujimoto Sunao 
Published: February 2005

AbstractDose‐dependent tension curves were recorded from the in vitro toad aortas by administration of endothelin‐1 and sarafotoxin‐S6b. The maximal contractile tensions by both drugs were evoked at a 10−8 M concentration. By a single dose application (10−8 M) of endothelin‐1 and sarafotoxin‐S6b to both endothelium‐preserved and denuded vessels, the induction of the endothelium‐dependent vasocontraction occurs after 2 min of administration.Ultrastructural changes of Weibel‐Palade bodies such as decrease in electron density, swelling with a wide peripheral halo, and expulsion of their contents in a manner of exocytosis become evident within 2 min after administration of these drugs. These findings indicate that some vasocontractile substances in Weibel‐Palade bodies are extracellularly discharged by endothelin‐1 and sarafotoxin‐S6b. © 1993 Wiley‐Liss, Inc.
A study of the chick thymus microenvironment during development: Analysis by monoclonal antibodies against thymic epithelium
Authors: Paz P. , Sánchez A. , Melcóan C. , Fernández J. G. , Chamorro C. A. 
Published: February 2005

AbstractThe process of T‐lymphocyte differentiation within the thymus involves a series of molecular interactions. In this work we have carried out an analysis of the chick thymus microenvironment in order to evaluate its heterogeneity during development. We have produced 11 monoclonal antibodies whose staining patterns detected by the immunoperoxidase technique allowed us to divide them into five groups. A first group (E19‐E2, P0‐E5, and P15‐T1) binds to thymic medullary stroma showing a reticular pattern on medullary epithelial cells and whose significance would be related to thymic stromal secretion. The second group of monoclonal antibodies (P15‐T3) stains thymic corpuscles of 10‐ and 15‐day chicks. The third group of antibodies includes P0‐E1, P0‐E3, P5‐A6, and P15‐T2 whose staining pattern is both medullary and cortical. The fourth group (P10‐HB1 and P10‐HB2) binds to thymic stromal and cortical thymocytes, and the fifth group (P5‐A1) is characterized by the staining of medullary vessels of 5‐day chicks. These five groups of monoclonal antibodies corroborate the existence of an antigenic diversity of the chick thymus microenvironment. Their possible relationships with T‐cell differentiation and stromal‐thymocyte interactions are discussed. © 1993 Wiley‐Liss, Inc.
An electron microscopic study of the harderian gland of the Syrian hamster with particular reference to the processes of formation and discharge of the secretory vacuoles
Authors: Lóapez J. M. , Tolivia J. , Alvarez‐Uría M. , Payne A. P. , McGadey J. , Moore M. R. 
Published: February 2005

AbstractThe lipid‐secreting cells of the Harderian gland of the Syrian hamster were studied using light, transmission, and scanning electron microscopy. Three morphologically different secretory cell types are identified in the gland: type I and II cells of the male gland and, distinct from either, the female gland cell. In all secretory cell types, lipid droplets in the cytoplasm were surrounded by unit membranes. Ultrastructural evidence of the involvement of the Golgi apparatus in the formation of the secretory vacuoles was obtained. The process of secretion involved the fusion of the boundary unit membrane of the vacuole with the plasma membrane and the release of the vacuolar content alone into the lumen. No evidence of holocrine processes was observed in this study. In addition to lipids, vacuoles contained materials whose solubility properties clearly differed from those of lipids. There appear to be variations in the ultrastructural characteristics of the vacuole content of the different types of secretory cell. © 1993 Wiley‐Liss, Inc.
Distribution of dystrophin and neurofilament protein in muscle spindles of normal and mdx‐dystrophic mice: An immunocytochemical study
Authors: Nahirney Patrick C. , Ovalle William K. 
Published: February 2005

AbstractDystrophin is a high molecular weight protein localized under the sarcolemma of normal extrafusal muscle fibers but absent in skeletal muscle of Duchenne muscular dystrophy patients and mdx mice. Muscle spindles in the soleus of 32‐week‐old normal and age‐matched mdx mice were examined by immunocytochemical methods to determine the localization of dystrophin in polar and equatorial regions of the intrafusal fibers. Spindles were serially sectioned in transverse and longitudinal planes, and were double‐labelled with an antibody to dystrophin and with an antibody to a 200 kD neurofilament protein, which revealed their sensory innervation. By fluorescence microscopy, intrafusal fibers in the soleus of mdx mice were deficient in dystrophin throughout their lengths, whereas their sensory nerve terminals stained intensely with the nerve‐specific antibody and appeared unaltered in dystrophy. In the normal soleus, intrafusal fibers displayed a regional variability in the distribution of dystrophin. Polar regions of bag and chain fibers exhibited a peripheral rim of sarcolemmal staining equivalent to that seen in the neighboring extrafusal fibers. Dystrophin labelling in equatorial regions of normal intrafusal fibers, however, showed dystrophin‐deficient segments alternating in a spiral fashion with positive‐staining domains along the sarcolemma. Double‐labelling for dystrophin and neurofilament protein showed that these dystrophin‐deficient sites were subjacent to the annulospiral sensory nerve wrappings terminating on the intrafusal fibers. These findings suggest that dystrophin is not an integral part of the subsynaptic sensory membrane in equatorial regions of normal intrafusal fibers and thus is not directly related to sensory signal transduction. The complete absence of this protein in mdx intrafusal fibers indicates that these fibers exhibit the same primary defect in muscular dystrophy as seen in the extrafusal fibers. However, because of their small diameters, capsular investment, and relatively low tension outputs, dystrophic intrafusal fibers may be less prone to the sarcolemmal membrane disruption that is characteristic of extrafusal fibers in this disorder. © 1993 Wiley‐Liss, Inc.
Morphometric analysis of intact sperm heads and of sperm nuclei in the mouse
Authors: Pogany Gilbert C. , Linder Kathleen A. 
Published: February 2005

AbstractA morphometric analysis of mouse sperm and of their nuclei was undertaken to investigate their respective post‐testicular maturation. Sperm were collected from the testis, caput and cauda epididymidis, and their corresponding nuclei were isolated. Results indicate that the post‐testicular maturation of sperm is distinct from that of nuclei. The size of intact sperm heads increases in the caput followed by a subsequent decrease in the cauda. In contrast, sperm nuclei decrease progressively in size. In general, a greater magnitude and number of alterations in intact heads and nuclei occur while in transit from the testis to the caput than during passage to the cauda epididymis. These results suggest that the period immediately following their release from the testis is crucial to the complete morphological maturation of sperm heads and nuclei. © 1993 Wiley‐Liss, Inc.
Neuropeptide distributions in the colon, cecum, and jejunum of the horse
Authors: Burns Gilbert A. , Cummings John F. 
Published: February 2005

AbstractThe pelvic flexure portion of the equine large colon is the proposed location of a pacemaker mechanism. This study was conducted to ascertain whether the distribution of certain putative neurotransmitters differs at the pelvic flexure compared to other sampling sites. Tissue samples were collected from the intestinal tracts of six horses. Serial sections from these samples were reacted with primary antisera specific for substance P, vasoactive intestinal polypeptide (VIP), methionine‐Enkephalin, and calcitonin gene‐related peptide (CGRP).The regional distribution of immunoreactive neuronal elements was uniform for each of the neuropeptides except VIP. Although neurons exhibiting VIP‐like immunoreactivity were abundant throughout the colon, they were somewhat more plentiful near the apex of the pelvic flexure and the left dorsal colon. These neurons may participate in the initiation and propagation of the propulsive/retropulsive contraction waves, which emanate from this location and are believed to lend a sphincter‐like capacity to the pelvic flexure. The submucosal plexus was replete with neurons with intense substance P and VIP‐like reactivity. Reactive fibers left submucosal ganglia to project to the intestinal mucosa, reflecting a possible secretogogic role for these neurons. This role may be especially important for the horse as a hindgut fermenter. There were abundant methionine‐Enkephalin and substance P‐like reactive varicosities throughout the myenteric plexus, many of which established a pericellular plexus of varicose fibers. The abundance of these varicosities, which may correlate with a high degree of neuronal integration, did not vary regionally. These data may enhance our understanding of both normal colonic peristalsis and motility disorders caused by a depletion of these neuropeptides. © 1993 Wiley‐Liss, Inc.
Changes of lectin staining pattern of the Golgi stack during differentiation of the ameloblast in developing rat molar tooth germs
Authors: Matsuo Saburou , Ichikawa Hiroyuki , Kurisu Kojiro , Wakisaka Satoshi , Kiyomiya Ken‐Ichi , Kurebe Masaru 
Published: February 2005

AbstractChanges of lectin staining patterns in the Golgi stack during cell differentiation were examined in the ameloblasts of developing rat molar tooth germs, using HRP‐labeled lectins: Canavalia ensiformis (Con A), Griffonia simplicifolia I (GS‐I), Glycine max (SBA), Ulex europeus I (UEA‐I), Triticum vulgaris (WGA), and Arachis hypogaea (PNA). The Golgi stacks of the inner enamel epithelial cells and the presecretory ameloblasts were stained with the lectins, although the staining strength and pattern varied among the stacks with each lectin. In some cases, the reaction products for the lectins were observed in most or all saccules of the Golgi stack. In the secretory ameloblasts, however, discrete staining patterns of the Golgi stack were found for each lectin. The reaction products deposited in definite saccules of the Golgi stack of the secretory ameloblast, especially for UEA‐I and PNA which stained only the trans Golgi saccules of the stack. The reaction‐positive saccules distributed more extensively in the Golgi stack of the inner enamel epithelial cell and the presecretory ameloblast than in the secretory ameloblast. These findings suggest that the Golgi stack is not fully compartmentalized in the inner enamel epithelial cell and the presecretory ameloblast. It is proposed that, in the differentiating ameloblast, various glycosyltransferases may coexist in most saccules of the Golgi stack. © 1993 Wiley‐Liss, Inc.
Bone formation is not coupled to bone resorption in site‐specific manner in adult rats
Authors: Chow Jade W. M. , Badve Sunil , Chambers Timothy J. 
Published: February 2005

AbstractThe trabecular bone of the secondary spongiosa of mature rats shows a coupling of bone formation to resorption. It has been clearly shown that in adult man the coupling of formation and resorption involves a site‐specific sequence of events, in which bone resorption is normally followed, at the same site, by bone formation. Whether the coupled processes of bone resorption and formation also occur at the same site in the rat is controversial. To elucidate the spatial relationship between bone formation and resorption in the rat, we compared the percentage of crenated and non‐crenated cement lines with the percentage of crenated and non‐crenated bone surfaces in the proximal tibia of adult rats aged 16 weeks to 2 years. A similar comparison was also made using bone from adult human iliac crest.We found that the trabecular bones of 16‐week‐old and 7‐month‐old rats exhibited a low percentage (7–11%) of crenated cement lines, which is opposite to the proportion (88%) we observed in human trabecular bone. In contrast, the surfaces of rat bone trabeculae showed a similar low proportion of crenated surface to human bone (rat 1.1–1.4% vs. 5% in humans). In older (2 years) rats, in which bones have ceased to grow in length, the percentage of cement lines that were crenated increased to 45%. These results imply that the major proportion of bone formation in the trabecular bone of growing rats occurs on non‐resorbed surfaces. Thus, although there is substantial evidence that bone formation is coupled to resorption in the rat, such that increased resorption is associated with increased formation, and suppression of resorption suppresses bone formation, bone formation does not necessarily occur on a previously resorbed site. This suggests that in the rat, the processes are not coupled by local release of cytokines or local cell interactions but by some other signal, such as mechanical stimulation. Since site‐specificity appears not to be crucial to the coupling of formation to resorption, the greater site‐specificity of coupling in man, and in older rats, may be attributable to a more static skeleton, which engenders a closer spatial correlation between bone formation and the resorption that induced it. © 1993 Wiley‐Liss, Inc.
Stereological study of mouse uterine and in vitro grown blastocysts: Cell numbers and volumes
Authors: Hurst Peter R. , Leeuwenberg Brenda R. , Ellis Leslie M. 
Published: February 2005

AbstractMouse blastocysts were studied to determine if there were differences in cell number and volumes between those that were (1) derived from the uterus prior to implantation on the afternoon of day 4 of pregnancy and (2) those that were cultured for 72 hr from two‐cell‐stage embryos. Blastocysts were fixed, embedded in resin, and serially sectioned at 1.5 or 2 μm. Photographic prints of alternate sections were used to count the numbers of inner cell mass (ICM) and trophectoderm cells. Cavalieri's direct estimator was applied to the same prints to estimate the volume of the whole blastocyst. Point counting was used to determine the volumes of the ICM, trophectoderm, and zona pellucida. The number of cells and size of the ICM were similar between the two groups of blastocysts, although it was found that the ICM of uterine embryos that did not have a zona pellucida were smaller than the ICM of those that did. There were twice as many trophectoderm cells in the blastocysts that were cultured from two‐cell embryos, and these cells were also found to be larger. Furthermore, the volume of the zona pellucida was less in the uterine blastocysts. This study indicates that, while trophectoderm proliferation is enhanced in vitro, the ICM is more constant and thus may be self‐regulating and independent of the growth conditions of the blastocyst as a whole. This study also suggests partial zona lysis occurs in utero and occurs either at a reduced rate or not at all in vitro. © 1993 Wiley‐Liss, Inc.
Structural and functional properties of trophoblast cells of mouse egg‐cylinders in vitro
Authors: Olovsson Matts , Nilsson B. Ove 
Published: February 2005

AbstractEmbryos at the egg‐cylinder stage were obtained by culturing blastocysts in vitro on an agarose surface for 4 days. The adhesiveness and outgrowth activity of the trophoblast of the egg‐cylinder were compared with those properties of the flushed adhesive blastocyst. Trophoblast cells of egg‐cylinders were found to be more adhesive and their outgrowth activity greater than in the case of trophoblast cells of adhesive blastocysts. The cultured egg‐cylinders presented two subpopulations of giant trophoblast cells. They represent probably two stages of differentiation of the same trophoblast population. The most distinctive morphological differences of these subpopulations were that the surface of one was covered with small blebs and the cytoplasm had relatively few ribosomes, while the surface of the other subpopulation was covered with large blebs and microvilli and the cytoplasm was rich in ribosomes and large, dense granules. The two types of giant trophoblast cells of the day 7 implantation site consist of one subpopulation whose cytoplasm has few organelles, and the other subpopulation, whose cytoplasm is rich in ribosomes, lysosome‐like bodies, and heterophagosomes. Hence, we conclude that the in vitro grown trophoblast cells have counterparts in the in vivo implanting embryos. The lectin binding pattern of the agarose cultured egg‐cylinder trophoblast cells was similar to that of the adhesive and/or invasive trophoblast cells grown in vivo.Thus, the in vitro grown egg‐cylinders are appropriate material for the analysis of trophoblast cells at the invasive stage of implantation. © 1993 Wiley‐Liss, Inc.
Occurrence of a third type of secretory cell in the acinus of the rat submandibular gland
Authors: Nagato Toshikazu , Nagaki Masami 
Published: February 2005

AbstractA new, third type of secretory cell was found in the acini of the submandibular gland in rat. In paraffin sections stained with hematoxylin‐eosin or reacted with periodic acid‐Schiff, acini containing the third type of secretory cells were found as a mass of darkly stained secretory endpieces at the periphery of the lobule. In semi‐thin sections stained with toluidine blue, these cells showed numerous dense secretory granules in their cytoplasm. Some acini consisted entirely of these cells, whereas other acini consisted of an admixture of such cells and typical seromucous cells. Acini containing the third type of secretory cell tended to form clusters. Electron microscopically, the cells had well‐developed rough endoplasmic reticulum and Golgi apparatus. The secretory granules showed a wide range of variation in substructure, even within the same cell. Well‐developed intercellular interdigitation and intercellular canaliculi also were observed between adjacent third type of secretory cells. Although little is known about the biological significance of these cells and the properties of their secretory granules, the present study shows that the rat submandibular gland possesses three types of secretory cells in their secretory endpieces. © 1993 Wiley‐Liss, Inc.
Ultrastructural characteristics of primordial germ cells in the quail embryo
Authors: Yoshinaga Kazuya , Nakamura Masao , Ukeshima Atsumi 
Published: February 2005

AbstractAn avian species, the quail has become a desirable animal model in experimental embryology and reproductive biology. To understand the ultrastructural characteristics of primordial germ cells (PGC) of this species, we studied PGC in the Japanese quail (Coturnix coturnix japonica) embryo at various developmental stages from their appearance in the germinal crescent through migration to settlement in the gonadal ridges by means of electron microscopy. The results were compared with those of another well‐known avian species, the chick. Several ultrastructural characteristics of quail PGC not described previously in chick PGC were observed as follows: (1) No glycogen particles were detected in the cytoplasm at any stage examined. (2) Electron‐dense and membrane‐bounded granules were found in the PGC cytoplasm during the sexually indifferent gonadal stages. (3) Quail PGC were characterized by a prominent nucleolus associated with condensed chromatin (heterochromatin), and the developmental changes of the nucleus, were noted; the nucleolus initially appeared as a compact mass at the germinal crescent stage and became dispersed at later stages during the colonization of the gonadal ridges. These findings suggest several physiological and functional differences in the cell cycle between these two avian species. This is the first report describing detailed ultrastructural characteristics of PGC in the quail embryo. © 1993 Wiley‐Liss, Inc.