bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of age on nuclear bodies and nuclear volume in pituicytes of the rat neurohypophysis
Authors: Lafarga M. , Berciano M. T. , Pérez‐Fígares J. M. , Andrés M. A. , Maquiera E. 
Published: February 2005

AbstractThis study has analyzed age‐related changes in the nuclear organization of pituicytes of the rat. The cytological study of the cell nucleus and the quantitative analysis of nuclear bodies (NBs) were performed on ultrathin sections. Nuclear diameter, perimeter, and area were measured on semithin sections, and nuclear volume was estimated from these data. The nucleolus was mainly composed of a few large fibrillar centers with their associated dense fibrillar component, whereas the granular component tended to form large masses at the nucleolar periphery. The most frequent configuration of NBs was a globular inclusion composed of a fibrillar capsule with a core that contained a few electron‐dense granules. Intranuclear glycogen was detected on rare occasions and only in old rats. The proportion of nuclear sections containing NBs increased significantly from 1.5% in 3‐month‐old rats to 8.6% in 18‐month‐old rats. A significant increase in the nuclear volume was detected in older rats with respect to the younger ones (157±69 vs. 98±43 μm3, mean ±S.D.). Our results suggest an age‐related activation of nuclear metabolism in pituicytes resulting in a nuclear expansion and an increase in the frequency of appearance of NBs. This activation might be a reactive cellular event induced by the degenerative changes in neurosecretory nerve endings naturally occurring in older animals.
Adaptation of diaphyseal structure with aging and increased mechanical usage in the adult rat: A histomorphometrical and biomechanical study
Authors: Jee Webster S. S. , Li Xiao Jian , Schaffler Mitchell B. 
Published: February 2005

AbstractThe experimental increase in mechanical usage or overloading of the left hindlimb was produced by immobilization of the contralateral hindlimb. The right hindlimb was placed in a flexed position against the body and was immobilized using an elastic bandage. Some control animals were sacrificed initially at time zero and increased mechanical usage and age‐matched control animals were sacrificed after 2, 10, 18, and 26 weeks of treatment. All animals received double bone fluorochrome labeling prior to sacrifice. Cortical bone histomorphometry and cross‐sectional moments of inertia were determined. Marrow cavity enlargement and total cross‐sectional area expansion represented the age‐related cortical bone changes. Increased mechanical usage enhanced periosteal bone modeling in the formation mode and dampened endocortical bone remodeling and bone modeling in the resorption mode (resorption drift) to create a slight positive bone balance. These observations are in general agreement with Frost's postulate for mechanical effects on bone modeling and remodeling (Frost, H.M. 1987b. Bone “mass” and the “mechanostat.” A proposal. Anat. Rec. 219:1–9). The maximum moment of inertia did not change significantly in either control or overloaded tibial shafts. The minimum and polar moment of inertias in overloaded bones increases over those of controls at 18 and 26 weeks of the experiment.
The structural organization and adrenergic innervation of the carotid arterial system of the giraffe (Giraffa camelopardalis)
Authors: Kimani James Kirumbi , Opole Isaac O. 
Published: February 2005

AbstractThe sympathetic innervation of the giraffe (Giraffa camelopardalis) carotid arterial system is described in this study using the sucrose‐potassium phosphate‐glyoxylic acid (SPG) method. The brachiocephalic and bicarotid trunks showed a paucity of sympathetic innervation. Smooth muscle nests observed in the outer layers of the tunica media in these arteries revealed a rich network of sympathetic nerve fibres. The common carotid artery showed numerous sympathetic nerve fibres particularly in the outer muscular zone of the tunica media. The internal maxillary, ramus anastomoticus, and arteria anastomotica also revealed a rich sympathetic innervation and a deep penetration of the nerve fibres into the tunica media. It is suggested that the rich sympathetic innervation of the giraffe carotid arteries maintains a basal tonic state in the smooth muscle in the tunica media. This, in turn, may enable the animal to maintain a relatively high rate of blood flow in the carotid arteries in diastole despite the pressure run‐off. It is further suggested that the muscular structure and dense sympathetic innervation of the internal maxillary and its branches to the carotid rete mirabile provide the animal with an array of mechanisms to modulate its cranial circulation particularly when it bends its head to drink.
Ultrastructural study of the hyaline layer of the starfish embryo, Pisaster ochraceus
Authors: Campbell Stephen S. , Crawford Bruce J. 
Published: February 2005

AbstractThe hyaline layer (HL) is a multilayered extracellular matrix (ECM) that coats the external surfaces of sea urchin and starfish embryos. It is thought to protect and lubricate the embryo, stabilize the blastomeres during morphogenesis, and regulate nutrient intake. Ultrastructural studies of chemically fixed embryos have shown the HL to consist of two to four sublayers. However, since chemical fixatives may cause collapse and alter the positions and antigenicity of the extracellular components, fixation methods that exclude chemicals may reveal a picture of the HL closer to what is present in vivo. Freeze substitution, a fixation method whereby tissues are rapidly frozen and dehydrated at low temperatures, has proved useful for fixing material rich in ECM. In this study, embryos of the starfish Pisaster ochraceus were fixed for microscopy using freeze substitution and three chemical methods in order to determine, as accurately as possible, the structure of the HL. Embryos appear to be best preserved by freeze substitution and demonstrate a HL consisting of at least six distinct sublayers. Based on staining with anionic dyes, most sublayers appear to contain glycosaminoglycans. Freeze substituted embryos, which were also stained with monoclonal antibodies raised against their ECM, revealed that some molecules are common to all six sublayers, whereas other molecules may be restricted to specific sublayers. This suggests that each sublayer could have a different function. Additional evidence suggests that microvillus associated bodies, present in other marine invertebrate embryos, may anchor the asteroid HL to the cell surface microvilli.
Alteration of the mammotroph Golgi complex by the dopamine agonist 2 BR‐α‐ergocryptine (CB‐154) in ovariectomized estrogen primed rats
Authors: Poole Max C. , Easley Charles S. , Hodson Charles A. 
Published: February 2005

AbstractThe present study examined the acute effects of 2 Br‐α‐ergocryptine (CB‐154, a dopamine agonist) on mammotroph organelles during prolactin (PRL) suppression. Ovariectomized estrogen‐primed rats received a single injection (sc) of 0.5 mg CB‐154 and the animals were killed at intervals following injection. The anterior pituitary glands were fixed for electron microscopy and immunocytochemistry was used to confirm mammotroph identification. Serum PRL levels were determined by RIA. Following CB‐154 administration, serum PRL was significantly (P ≤ 0.05) reduced within 15 minutes and was suppressed (P ≤ 0.01) to ovariectomized levels at 2 and 6 hours. A stereological analysis of mammotrophs in the central regions of the anterior pituitary showed that the Golgi complex volume was significantly (P ≤ 0.05) reduced at 2 hours after CB‐154 treatment. However, the Golgi complex volume had recovered by 6 hours post CB‐154 injection. In addition, the volumes of the mammotroph cells, the mature secretory granules, and the secondary lysosomes had significantly increased by 6 hours. There were no significant changes in any of the organelles following CB‐154 in the mammotrophs from the peripheral regions of the gland. These studies show that the Golgi complex is especially susceptible to acute morphological changes induced by bromocryptine and that the mammotrophs in the central regions are more responsive to CB‐154 than those in the peripheral regions.
Simultaneous localization of histamine and factor VIII‐related antigen in the endothelium of the human umbilical vein
Authors: Ueda Hiroshi , Doi Yoshiaki , Sakamoto Yoshitaka , Hamasaki Kunshige , Fujimoto Sunao 
Published: February 2005

AbstractSimultaneous immunoelectron microscopic localization of histamine and factor VII‐related antigen was examined on the same ultrathin section of the endothelium of the human umbilical vein from full‐term deliveries by means of the double‐immunolabeling technique.Small gold particles demonstrating antibody reaction with histamine are preferentially located in the cytoplasmic matrix and organelles, especially in mitochondria and on the luminal membrane surface of the endothelial cells. The gold particles representing histamine immunoreactivity also located on some of Weibel Palade (WP) bodies. In contrast, large gold particles demonstrating factor VII‐related antigen are concentrated preferentially on most WP bodies. Single labeling of either histamine or factor VIII‐related antigen shows similar results to those of the double labeling.The present study indicates that some WP bodies are involved in storage of both factor VIII‐related antigen and histamine, but others store factor VIII‐related antigen only. This difference in contents of WP bodies may be induced during the development and maturation process of this inclusion. At any rate, it is reasonable to consider that WP bodies have important roles in both vascular tonus and hemostasis during the vascular obliteration.
Tropic effects of otic epithelium on cochleo‐vestibular ganglion fiber growth in vitro
Authors: Hemond Sharon G. , Morest D. Kent 
Published: February 2005

AbstractSensory nerve fibers of the cochleo‐vestibular ganglion (CVG) innervate the otic epithelium in the early chick embryo by directed growth. To see if the target tissue could exert a tropic influence, we co‐cultured CVGs from chick embryos (Hamburger‐Hamilton stages 16–30) in a 3D collagen matrix with their normal target epithelium or with other epithelial tissues taken from the same or different stages of development. The pattern of neurite outgrowth and the viability of the CVG after five days in vitro were assessed histologically with a silver method. On the basis of the patterns of neurite outgrowth directed toward the epithelium the cultures were classified as having slightly, mostly, exclusively, or no directed outgrowth. Of 49 cultures containing otic epithelium, 33 had mostly or exclusively directed growth patterns. This effect did not depend on any particular stage difference between co‐cultures or on their viability in vitro. Cultures of non‐sensory otic epithelium (endolymphatic duct) also presented directed growth patterns. Co‐cultures with ectoderm from forelimb or visceral arch had little, if any, directed growth. The directed growth could not be explained simply as a result of guidance by non‐neuronal cells or of the viability of the explants. The results are consistent with the hypothesis that the otic epithelium provides a tropic factor that attracts growing CVG fibers.
Morphological and northern blot analysis of juxtaglomerular cells in experimental hydronephrotic mice
Authors: Kon Yasuhiro , Takahashi Shigeru , Fukamizu Akiyoshi , Murakami Kazuo , Hashimoto Yoshiharu , Sugimura Makoto 
Published: February 2005

AbstractThe purpose of this study is to demonstrate the developmental changes of the experimental hydronephrotic kidney using immunohistochemical, histoplanimetrical, and Northern blot techniques. At 1 month after ligation of the ureter, a large number of renin‐positive cells were detected immunohistochemically even at a dilution of 1:10,000 in this hydronephrotic kidney; however, there were few renin‐positive cells in the non‐ligated side. At 6 months after ligation, no difference in reactivity for renin between ligated and non‐ligated kidneys was demonstrated. In the morphometrical analysis of the renin‐positive region, the numerical value of the ligated side was already increased at 2 weeks, reached the highest value at 1 month, and then decreased gradually to almost the same value as the control kidney by the end of the experiment. On the other hand, the value of the non‐ligated side decreased immediately after the unilateral ligation, increased later, and finally reached almost the same value as the control kidney. In the Northern blot analysis, the activity of renin mRNA in the ligated side at 1 month after ligation was markedly higher than that in the non‐ligated side. However, the difference between the ligated and the non‐ligated sides was not demonstrated at 6 months and the value came to be almost the same as in the nonoperated kidney.
Morphologic and functional characteristics of subpopulations of murine lung fibroblasts grown in vitro
Authors: Penney D. P. , Keng P. C. , Derdak S. , Phipps R. P. 
Published: February 2005

AbstractFibrotic development is a common response of the lung to toxic or deleterious insult. For example, the lung is the dose‐limiting organ for irradiation of the thorax for primary or metastatic lesions, due in large part to latent fibrosis. The development of the fibrotic response reflects a cascade of cell‐cell and cellextracellular matrix interactions, the ultimate target of which is the fibroblast. There is increasing evidence of subpopulations of pulmonary fibroblasts, which may have differing roles in either the initiation or progression of fibrosis. Recently we described two fibroblast subpopulations from the murine lung, which differ in the presence or absence of the membrane antigen Thy‐1 (Phipps et al., 1989). These Thy‐1+ and Thy‐1− subpopulations are stable and differ in certain functions, such as the production of cytokines and the display of Class II MHC antigens. To determine the morphologic development of the two subpopulations and their growth characteristics in vitro, cultures of the two cell subtypes were prepared for transmission and scanning electron microscopy at varying stages of growth. Thy‐1+ fibroblasts are more spindle‐shaped, contain intracellular lipid, exhibit abundant cell‐cell contacts, and are capable of secreting large amounts of collagen and modest amounts of fibronectin. Thy‐1− fibroblasts are more rounded and spread, contain no intracellular lipid droplets, possess more intracellular microfilaments and microtubules, and synthesize less collagen and more fibronectin than do Thy‐1+ cells. There are no significant differences between the two subpopulations insofar as growth rates are concerned, but Thy‐1+ fibroblasts possess an additional DNA peak during periods of early growth.
Supra‐neuroectodermal cells and fibers on the primary nasal cavity and in the fourth ventricle of mouse and human embryos: Scanning and transmission electron microscopic studies
Authors: Otani Hiroki , Tanaka Osamu , Yoshioka Takafumi 
Published: February 2005

AbstractNeuroectoderm‐derived epithelia of the primary nasal cavity and the fourth ventricular floor and roof were observed by scanning (SEM) and transmission electron microscopy (TEM) and SEM‐TEM correlative views in mouse embryos of 9th to 13th days of gestation, and in 38 externally normal human embryos ranging at Carnegie stages from 13 to 18 (about 5 to 7 weeks of gestation). Smooth‐surfaced spindle‐shaped cells with one or more cytoplasmic processes and cord‐like cytoplasmic structures were observed by SEM on the wall of the primary nasal cavity of both species. They had morphological features similar to those of neuronal type 1 supraependymal (SE) cells and SE fibers on the floor and roof of the fourth ventricle in both species. Type 1 SE cells, SE fibers, and corresponding structures in the primary nasal cavity were localized in relation to the underlying developing nerve and vascular systems. Furthermore, their processes and fibers ran roughly parallel to these underlying structures and they penetrated the epithelial layer at the ends, suggesting a connection with underlying structures. From TEM and SEM‐TEM correlative observations, SE fibers in the fourth ventricle and cord‐like structures in the primary nasal cavity, both with a larger diameter, were deduced as single axon‐like processes or bundles of processes. Those fibers and cord‐like structures of smaller diameters were interpreted as elongated telophase bridges; both contained parallel packed microtubules and connected distant cells. Since these processes and fibers were generally longer and became fewer at later developmental stages, they appeared to be transient neuronal structures. They may play a development‐related role in such morphogenetic cell movements as in the developing nerve and vascular systems in the epithelial and/or subepithelial layers, but not as direct rudiments of adult nerve tissues. © 1992 Wiley‐Liss, Inc.
Nerve growth factor receptor (NGFR)‐like immunoreactivity in the perineurial cell in normal and sectioned peripheral nerves of rats
Authors: Yamamoto Miyuki , Kondo Hisatake , Iseki Shoichi 
Published: February 2005

AbstractThe occurrence of nerve growth factor receptor (NGFR)‐like immunoreactivity in the perineurial cells of sympathetic and sensory nerves was analyzed in normal controls and after surgical severance. In the normal nerve trunk, no cellular elements exhibited NGFR‐like immunoreactivity. Immunoreactivity was induced in the innermost perineurial cells and in all Schwann cells distal to a severed nerve. The acquisition of immunoreactivity in perineurial cells was also seen in deafferented sympathetic ganglia. On the other hand, the perineurial cells as well as axonal endings showed NGFR‐like immunoreactivity consistently in the terminal region of normal nerves, and this immunoreactivity was enhanced by nerve section. The present study clearly showed that different types of nerve terminals are ensheathed to different extents by perineurial cells which were first clearly identified by their NGFR‐like immunoreactivity: (1) nerve terminals were free of the perineurium far away from targets in the iris, (2) they were free of the perineurium at sites close to targets in the lingual epithelium, and (3) the perineurium ensheathed nerve terminals together with targets in Meissner's sensory corpuscle. The functional significance of the three different patterns of perineurial enclosure requires further examination. © 1992 Wiley‐Liss, Inc.
Detailed anatomy of the antebrachiocarpal joint in dogs
Authors: Mikić Ẑ. Dj. , Ercegan G. , Somer T. 
Published: February 2005

AbstractA comparative study of the anatomy of the antebrachiocarpal (AC) articulation was carried out in 30 adult dogs with 60 joints. Although a considerable degree of similarity was found between the AC joint in dogs and the corresponding wrist joint in humans, a number of differences between these two homologous joints were also noted. The distal end of the ulna in dogs directly articulates with the ulnar carpal and accessory carpal bones forming a specialized antebrachiocarpal arrangement more adapted to running. The accessory carpal bone in dogs is a massive, long bone and is strikingly different from its homologue in humans, the pisiform bone. The joint between the accessory and ulnar carpal bones, which corresponds to the piso‐triquetral joint in humans, is always connected with the AC joint, whereas in humans this communication could be found occasionally. The large radial carpal bone in dogs, characteristic for carnivores, corresponds to the fused scaphoid and lunate bones in humans, in whom this type of fusion is very rarely found. The palmar ulnocarpal and radiocarpal ligaments in dogs are distinctly intra‐articular, whereas in humans these ligaments are intracapsular. One of the controversies of the AC joint in dogs is a structure located between the distalmost parts of the radius and ulna forming a strong bond between these two bones and a part of the antebrachial articular surface. It is cartilage‐like and is composed of typical fibrocartilagineous tissue. Considering its location, form, and function, this structure in dogs should be regarded as the articular disc and so‐named; it is also concluded that it is a homologue to the articular disc of the distal radioulnar joint in humans. © 1992 Wiley‐Liss, Inc.
SEM of capillary pericytes prepared by ultrasonic microdissection: Evidence for the existence of a pericapillary syncytium
Authors: Wagner Roger C. , Hossler Fred E. 
Published: February 2005

AbstractRetia mirabile of the eel swimbladder were exsanguinated, perfusion‐fixed and subjected to prolonged osmication. They were then microdissected by ultrasonication which delaminated the capillary bed along planes which revealed the surfaces of arterial and venous capillaries. This procedure resulted in cleaned capillary surfaces largely free of connective tissue elements and basement membrane material. The arterial capillary segments were heavily invested with pericytes characterized by plump cell bodies containing nuclei and an extensive system of processes encircling the capillary wall. These processes exhibited a hierarchical organization consisting of primary, secondary, and tertiary elements arising roughly at right angles to each other. Primary and secondary processes exhibited frequent anastomoses and resulted in cytoplasmic continuity between adjacent cell bodies. Processes were also observed to form connections between pericytes on adjacent capillaries. These observations are evidence for the existence of a pericapillary syncytium in which cell bodies may be connected in series and in parallel throughout the arterial capillary bed. This syncytial organization would provide for a coordinated and global contractile response of pericytes to vasoactive hormones and other effectors. It may also provide for synchrony of nuclear division during developmental spread of pericytes along capillary surfaces.© Willey‐Liss, Inc.
Evidence for the glyoxyiate cycle in human liver
Authors: Davis Walter L. , Goodman David B. P. 
Published: February 2005

AbstractThe enzymatic activities unique to the glyoxylate cycle of higher plants and certain lower invertebrates, isocitrate lyase and malate synthase, have been demonstrated in homogenates prepared from human liver. Human liver can also carry out cyanide‐insensitive fatty acid oxidation from palmitate. Utilizing light microscopic immunocytochemistry with an antibody produced against Euglena malate synthase, this enzyme localizes in numerous ovoid granules in human hepatocytes. Also, immunocytochemistry using antibodies produced against rat fatty acyl‐CoA oxidase showed that this enzyme was localized in similar structures. With routine cytochemistry, catalase was seen in identical granular bodies. Both catalase and fatty acyl‐CoA oxidase are peroxisomal enzymes. The presence of malate synthase in liver homogenates was further confirmed by Western blot analysis. These data suggest that the human liver may be capable of utilizing the carbon backbone of fatty acids for carbohydrate synthesis since the glyoxylate cycle in lower organisms subserves this anabolic function.© Willey‐Liss, Inc.