bluuebunny/crossref_metadata_2025_split huggingface dataset:
Short‐term effects of androgen withdrawal on the structure of different epithelial cells in the rat epididymis
Authors: Moore H. D. M. , Bedford J. M. 
Published: February 2005

AbstractRat spermatozoa are highly dependent on the milieu of the normal epididymis for their maturation and survival, and die within a few days after androgenic support of the epididymal epithelium is withdrawn. The immediate changes in the ultrastructural organization of the epithelial cells of the rat epididymis, 2, 4, 6 and 14 days following castration have been monitored by morphometric analysis of localized regions of the caput and cauda epididymidis. While castration results in greater endocytosis by principal cells (Moore and Bedford, '79), many of their early structural changes following androgen withdrawal (disappearance of vesicles from the cell apex, reduction in rough endoplasmic reticulum, a drop in the volume of the Golgi cisternae and increase in lysosome content) seem indicative of inhibition of a secretory function. By contrast with the regressive response of the principal cell, the ultrastructure of clear cells in the cauda and of apical cells in the caput region appeared unchanged up to 14 days after castration. The implications of this evidence for specialized functions, and the suggestion of a differential androgen dependence among major cell types of the epididymal epithelium, are discussed briefly.
Fine structure of the oxynticopeptic cell in the gastric glands of an elasmobranch species (Halaelurus chilensis)
Authors: Rebolledo Ivan M. , Vial Juan D. 
Published: February 2005

AbstractGastric mucosa of an elasmobranch species was examined by electron microscope. The gastric glands contain one form of cell whose fine structure is similar to the cell that secretes both hydrochloric acid and pepsinogen of the amphibian gastric glands proper. These oxynticopeptic cells are characterized by: (a) a luminal surface with long projections of cytoplasm having dilatations in their thickness; (b) a tubulo‐vesicular system in the apical cytoplasm; (c) a great number of mitochondria, some of which are of great length; (d) a well developed granular endoplasmic reticulum and a conspicuous Golgi apparatus; and (e) a large nucleus with a conspicuous nucleolus. A fourth part of the cells are binucleated. Physiological implications of some of these ultrastructural features are discussed.
Morphologic variations and aging in the atrioventricular conduction system of large breed dogs
Authors: Sandusky George E. , Kerr Kirklyn M. , Capen Charles C. 
Published: February 2005

AbstractThe microscopic anatomy of the atrioventricular node, bundle of His, both bundle branches and surrounding fibrous cardiac skeleton was studied in 40 large breed dogs of various ages. In the AV conduction system of all dogs over five years of age there was an increase of fibrous connective tissue, an infiltration of adipose tissue, loss of conduction fibers and focal fibrosis extending from the central fibrous body.Fibrosis was seen in the summit of the interventricular septum posterior to the AV node in dogs of all ages. Chondroid metaplasia was consistently observed in the central fibrous body and the root of the aorta in large breed dogs, including ten Doberman Pinschers of all ages. This metaplasia varied from a few chondroblasts and chondrocytes to mature chondrocytes with mineralization. Bone formation was seen in eight dogs. These changes appeared in close approximation to the cardiac conduction system above the bundle of His. No degenerative changes were seen in the AV bundle. Approximately one‐half of the large breed dogs five years of age and older had thickened medial and intima proliferation in the small coronary arterioles supplying the AV node. The results of this study suggest that the presence of cartilage and bone in the central fibrous body is a normal occurrence in large breed dogs at all ages.
Failure of induced functional activity and cell deficit to restore preoperative cell number in paired accessory sex glands following unilateral ablation in castrated male mice
Authors: Alison Malcolm R. , McHanwell Stephen , Wright Nicholas A. 
Published: February 2005

AbstractThe proliferative response to testosterone propionate in the accessory sex glands of castrated male Balb/c mice has been studied when the glands were intact, and when the glands were unilaterally ablated. The response was analysed by serial measurements of DNA and weight, and by 3H‐thymidine labelling techniques. When stimulation is started at three days after castration, most seminal vesicle cells of intact glands carry out DNA synthesis to restore preoperative cell number, whilst the smaller reduction in coagulating gland DNA prior to stimulation results in only about 30% of cells carrying out DNA synthesis to restore former levels. In the unilaterally ablated glands of the 3‐day castrates, the cell kinetics of stimulated DNA synthesis and the net accumulation of DNA were similar to the intact glands. A much larger deficit in DNA was apparent in all glands of unstimulated 14‐day castrates, resulting in a much larger net accumulation of DNA following testosterone stimulation. No difference between intact and unilaterally ablated glands was detected, and despite prolonged stimulation DNA levels did not exceed preoperative values. Unlike gland DNA levels, gland weights exceeded those of non‐castrated mice following prolonged stimulation. However, unilateral ablation did not result in further weight increases in the remaining contralateral glands. It is concluded that the absence of the contralateral sex gland is not detected by the remaining partner during the response to the combined stimuli of a reduction in cell number (resulting from androgen deprivation), and testosterone propionate administration.
Morphologic effects of pressure changes on canine carotid artery endothelium as observed by scanning electron microscopy
Authors: Lee Mary M. L. , Chien Shu 
Published: February 2005

AbstractBy using scanning electron microscopy (SEM) we were able to follow the sequence of ultrastructural alterations of the luminal surface which occurred when specimens of canine carotid artery were subjected to controlled transmural pressures. Specimens of carotid artery were removed from dogs following fixation at experimental pressures ranging from 0 mm Hg to 100 mm Hg. The endothelium of specimens fixed at 0 mm Hg has parallel longitudinal ridges formed by the contraction of the underlying internal elastic lamina. With increasing transmural pressure, the luminal surface undergoes a gradual flattening of the endothelial ridges so that at 100 mm Hg, these ridges have completely disappeared. The observed morphologic changes of the arterial endo‐thelium indicate that SEM can provide good ultrastructural information on blood vessels subjected to controlled transmural pressure and that the pressure‐dependent alterations must be considered in studies on vascular structure and function.
The morphology of extrachoroidal ependyma overlying gray and white matter in the rabbit lateral ventricle
Authors: Page Robert B. , Rosenstein Jeffrey M. , Leure‐Dupree Alphonse E. 
Published: February 2005

AbstractA morphologic investigation of ependyma over gray matter (caudate nucleus) and over periventricular white matter (tapetum) of the rabbit lateral ventricle was undertaken prior to evaluation of morphological changes which occur with experimental hydrocephalus. Ependymal cells over the caudate nucleus are cuboidal and heavily ciliated. Numerous microvilli cover the cell surface. The lateral margins are straight and interdigitations between adjacent ependymal cells are absent. Ependymal cells over white matter are squamous. Nonciliated as well as ciliated cells contribute to the epithelial lining. Microvilli are present at the cell surface but tend to aggregate near the cellular borders. The lateral margins are convoluted and complex interdigitations are present between adjacent cells. Morphologic differences between ependymal cells over the caudate nucleus and those over periventricular white matter may help to explain the differential response to hydrocephalus observed in these two regions of the lateral ventricle.
Alterations in hepatocytes of mice fed a gallstone‐inducing diet: Occurrence of nuclear and cytoplasmic lipids
Authors: Saland L. C. , Napolitano L. M. 
Published: February 2005

AbstractMice fed a high cholesterol‐cholic acid (lithogenic) diet for one year develop fatty livers in addition to gallstones. Light and electron micrographs demonstrate large amounts of lipids in liver parenchymal cells, often to the exclusion of most other cytoplasmic organelles. In addition, some hepatocytes exhibit nuclear lipid pseudo‐ and true inclusions. Other prominent features of hepatocytes after lithogenic diet include segregation of nucleolar granular and fibrillar material. Accumulation of considerable collagen in extracellular spaces is also noted. Observations suggest changes induced by the cholesterol diet are comparable to cytologic alterations seen in spontaneous and drug induced hepatic tumors, as well as to more general “fatty metamorphosis” of the liver.
Mandibular growth retardation in corticosteroid‐treated juvenile mice
Authors: Silbermann Michael , Maor Gila 
Published: February 2005

AbstractJuvenile mice were treated for up to eight weeks with weekly doses of a synthetic analogue of cortisol:triamcinolone hexacetonide. The mandibular condylar cartilage was studied histologically and histochemically at regular intervals. Morphometric measurements were performed along the mandibular posterior vertical dimension (condylar process and ramus). By the second injection significant morphological changes were noted in the condylar cartilage, followed by retardation of bone growth. The most distinctive feature in the cartilage of triamcinolone‐treated mice was a marked increase in the dimension of its mineralized zone concomitant with a significant increase in the number of hypertrophic chondrocytes. The role of condylar cartilage in mandibular growth is discussed.
Intraspinal non‐neuronal cellular responses to peripheral nerve injury
Authors: Gilmore Shirley Ann , Skinner Robert D. 
Published: February 2005

AbstractThe accumulation of non‐vascular, non‐neuronal cells (designated herein as reactive cells) in association with perikarya of axotomized motor neurons has been described by many investigators. Recently Gilmore ('75) found that sciatic axotomy in immature rats resulted in the occurrence of reactive cells not only in the spinal ventral gray matter but also in the dorsal gray matter. To determine if the presence of these cells in the dorsal gray matter, a finding not reported by others, was related to the immaturity of the animal, sciatic axotomy was performed in rats ranging in age from 17 days to 16 months in the present study. Light microscopic evaluation of the spinal cords three or seven days post‐operatively showed that the reactive cells occurred consistently in both dorsal and ventral gray matter irrespective of age. Transection of tibial nerve or the nerve to the medial head of the gastrocnemius muscle elicited a cellular response in both dorsal and ventral gray matter, although transection of the latter nerve resulted in a much less obvious response. Crushing of the sciatic nerve was followed by a response of reactive cells not qualitatively different from that noted following transection. Transection of the sural nerve, primarily a sensory nerve, resulted in the presence of reactive cells in dorsal gray matter but not in the environs of motor neurons in the ventral gray matter. These findings suggest that the reactive cells in the dorsal gray matter of the spinal cord are associated with altered central processes of dorsal root ganglion cells.
Early cytodifferentiation of human prostatic urethra and Leydig cells
Authors: Kellokumpu‐Lehtinen P. , Santti R. , Pelliniemi L. J. 
Published: February 2005

AbstractThe ultrastructure of the urethral epithelium and mesenchyme of the 6‐ to 9‐week‐old human embryos was studied in order to reveal early morphological signs of prostatic development. The morphological changes of the urethral wall were correlated with the cytodifferentiation of the Leydig cells of the same embryos. Throughout the study the urethral epithelium had two or more layers of cuboidal cells. The ultrastructure of the cells was primitive and they did not achieve characteristics of the secretory prostatic cell. The surface cells had well developed apical junctions and slender cytoplasmic processes projecting into widened intercellular spaces appeared during the developmental period. The urethral mesenchyme showed the most salient changes. The mesenchymal cells adjacent to the urethral epithelium differentiated in the ninth week into fibroblast‐like cells with an elongated shape and cytoplasmic processes. Granular endoplasmic reticulum appeared in the cytoplasm and collagen fibers were seen in the intercellular space. Mesenchymal cell processes contacting the continuous basal lamina under the epithelium were present. No direct epithelio‐mesenchymal cellular contacts could be seen. The differentiation of the mesenchyme before the epithelial outgrowths suggests that the mesenchyme has an essential role in the glandular development.Electron microscopic study of the Leydig cells showed that the amount of agranular endoplasmic reticulum increased considerably in the ninth week. This agrees with earlier biochemical findings on the capability of Leydig cells to produce androgens by this time. The temporal relationship between the cytodifferentiation of Leydig cells and the urethral wall is consistent with the idea that in the human, fetal androgens induce prostatic development.
The topography of rat submandibular gland parenchyma as observed with S.E.M.
Authors: Brocco Steven L. , Tamarin Arnold 
Published: February 2005

AbstractThe parenchymal components of rat submandibular gland were examined by scanning electron microscopy after removal of the stromal connective tissue by acid hydrolysis and/or enzymatic digestion. Secretory acini have polymorphous topographies but usually consist of three to five truncated lobes emanating from a common hilus. They have a mean volume of about 33,000 μm3. Myoepithelial cells are associated with the deeper acini of the gland where they cover ⋍ 54% of the surface area of their allied acini. Each flattened myoepithelial cell has a central perikaryon that gives rise to four or five broad primary processes that bifurcate two or three times to produce a total complement of 20 to 40 terminal processes per cell, each 0.5 μm to 1.7 μm wide. The terminal processes of adjacent myoepithelial cells tend to slightly overlap and to attach to each other by desmosomes forming a network over adjacent acini. The components of the duct system are examined and each characterized by salient features as observed with the SEM.
The occurrence of ciliated and mucous cells in the peripapillary trench of the rat tongue
Authors: Toyoshima Kuniaki , Shimamura Akitatsu 
Published: February 2005

AbstractCiliated cells surrounded by mucous cells were found near the base of the peripapillary trench of the rat circumvallate papilla. The ciliated cells occurred singly or in small groups. Each cilium showed the nine plus two filament pattern characteristic of motile cilia.We consider that these cells function in wetting the taste pores, circulating saliva containingtastants and removal of debris from the papillary trench.
Synthesis of secretory and plasma membrane glycoproteins by striated duct cellsof rat salivary glands as visualized by radioautography after 3H‐fucose injection
Authors: Hand Arthur R. 
Published: February 2005

AbstractThe ability of the striated ducts of rat salivary glands to incorporate 3H‐fucose into glycoprotein was studied by light and electron microscope radioautography. At 3.5 to 20 minutes after intravenous injection, the majority of the radioautographic grains in the ducts of the parotid gland were localized to the Golgi apparatus. By 40 minutes, the percentage of grains over the Golgi apparatus had decreased; a corresponding increase in grains occurred over small (0.1‐0.4 μm) apical granules and the highly infolded basal and lateral plasma membranes. By two hours, less than 10% of the label was associated with the Golgi apparatus, while 26% and 28% were attributed to the apical granules and plasma membrane, respectively. By 8 to 12 hours after injection, the number of grains over the apical cytoplasm had decreased, suggesting luminal discharge of the apical granules. In contrast, the basal and lateral plasma membranes remained labeled up to 30 hours after injection as judged by the distribution of grains in light microscope radioautographs. Mitochondria appeared capable of independent incorporation of fucose, accounting for about 20% of the grains from ten minutes to two hours after injection. Comparable results were obtained in the striated ducts of the submandibular and sublingual glands.These results indicate that the striated duct cells readily incorporate 3H‐fucose into newly‐synthesized glycoproteins. A portion of these are secretory glycoproteins which are packaged and stored in the apical granules, and a portion are membrane glycoproteins which are incorporated into the extensive plasma membrane of these cells.
Selective labeling of mesenteric lymph nodes: Cell production and emigration ofnewly formed lymphocytes to other organs
Authors: Pabst R. , Trepel F. 
Published: February 2005

AbstractLymphocyte production by mesenteric lymph nodes of normal young pigs was studied by intranodal injections of either tritiated thymidine or tritiated deoxycytidine as DNA precursors. One or two days after selective labeling of the mesenteric lymph nodes the relative and absolute number of lymphocytes derived from mesenteric lymph nodes were determined autoradiographically in the following organs: mesenteric, cervical and inguinal lymph nodes, spleen, thymus, bone marrow, peyer'spatches, tonsil, different regions of the gut, lung and liver. The overall cell production of mesenteric lymph nodes, as derived from the sum of all labeled cells one day after labeling, was estimated to be about 7 × 109 lymphocytes. Up to 40% of all newly formed lymphocytes had already left the lymph nodes within one day and were found in all organs studied. There was a preferential homing to the mucosa of the small intestine, but a considerable number migratedto the spleen and even to the thymus and bone marrow. In lymphoid organs all labeled cells were small and medium‐sized lymphocytes one and two days after labeling. In cervical lymph nodes, spleen, tonsil and peyer's patches the relative distribution to T and B cell areas was determined. There was an obvious preference of newly formed lymph node cells to home to T cell areas. The differences of labeling between thymidine or deoxycytidine were surprisingly low.
Development of villus absorptive cells in the human fetal small intestine: A morphological and morphometric study
Authors: Moxey Pamela Colony , Trier Jerry S. 
Published: February 2005

AbstractWe describe the sequential ultrastructural changes in villus absorptive cells of human fetal small intestine between 9 and 22 weeks of gestation. In concert with villus formation at 9 to 10 weeks, a complex membranous system designated the apical tubular system appeared in the apical cytoplasm of absorptive cells. The apical tubular system consisted of deep invaginations of plasma membrane and membrane‐bounded vesicles and tubules. Some elements of this system were characterized by linear arrays of particles on the inner (luminal) membrane leaflet. After villus formation, many lysosomal elements designated “meconium corpuscles” also appeared in the apical cytoplasm. Modified morphometric studies suggested that both the apical tubular system and the lysosomal elements were more extensively developed in the distal than in the proximal intestine, were most abundant at 15 to 17 weeks, and decreased by 18 to 22 weeks. Morphometry also showed an inverse relationship between the relative surface density of the apical tubular system and microvillus membrane, suggesting the possible derivation of elements of the former from the apical plasma membrane. Exposure of intestine to ferritin for 8 to 40 minutes in vitro revealed ferritin in elements of the apical tubular system of 12– to 20‐week fetuses. There was no evidence of transport of ferritin across absorptive cells. Distinctive membranous bodies composed of convoluted membrane‐bound cisternae separated by narrow channels of cytoplasmic matrix were seen in the Golgi region and apical cytoplasm of fetal absorptive cells between 14 and 22 weeks. In a single 22‐week fetus, there was marked proliferation of smooth endoplasmic reticulum, a decrease in cytoplasmic glycogen and loss of most lysosomal and apical tubular elements in the proximal but not the distal intestine. Thus, by the end of the second trimester, the structure of absorptive cells in proximal intestine was remarkably similar to absorptive cells in adult intestine.
Localization of tritiated norepinephrine in the renal arteriolar nerves
Authors: Barajas Luciano , Wang Patricia 
Published: February 2005

AbstractThe innervation of the glomerular arterioles was investigated by light and electron microscopy autoradiography for localization of exogenous tritiated norepinephrine. By light microscopy accumulations of grains were seen associated with afferent arterioles and in lesser numbers with efferent arterioles and neighboring tubules. Accumulations of grains were noted to be in contact with juxtaglomerular granular cells. Electron microscopy autoradiography revealed that nearly two‐thirds of the silver grains were on axons. Most of the label was on varicosities packed with small, clear and dense‐cored, vesicles. Most varicosities, including those in contact with smooth muscle, juxtaglomerular granular or tubular cells, were labeled. Some varicosities which appeared unlabeled in a given section were labeled in subsequent sections. These findings are consistent with the notion that the glomerular arterioles are innervated mainly by adrenergic nerves. This view is supported by the previously reported observations of the concomitant virtual disappearance of fluorescent and acetylcholinesterase‐positive nerves from the region of the glomerular arterioles after two injections of six‐hydroxydopamine (a drug which selectively destroys adrenergic nerves) and the presence of small dense‐cored vesicles in all axons of the juxtaglomerular region when examined by serial section electron microscopy.
Unipolarity of fibroblasts in rodent periodontal ligament
Authors: Beertsen Wouter , Everts Vincent , Brekelmans Margot 
Published: February 2005

AbstractIn order to investigate whether fibroblasts in rodent periodontal ligament have a structural polarity, the position of the Golgi apparatus or the centriolar region in the cells was studied using light and electron microscopy. It appeared that, in the periodontal ligament of continuously erupting mouse and rat incisors, centrioles in fibroblasts on the tooth side of the ligament are preferably located in the anterior (occlusally directed) part of the cytoplasm. Polarity of fibroblasts in a single direction was less pronounced or absent on the bone side of the tissue. In the mouse, fibroblasts in the connective tissue adjacent to the incisor also contained an extensive system of cytoplasmic microtubules, whereas in the fibroblasts on the bone side of the ligament microtubules were less frequent.Unipolarity of fibroblasts was also observed in the periodontal ligament of the rat maxillary first molar, which is characterized by a limited eruption. Here, the Golgi region was usually situated in that pole of the cells that was directed towards the alveolar wall and the occlusal plane.It is suggested that structural polarity of fibroblasts in the periodontal ligament of rodent teeth is associated with orientation of functional activities of the cells, such as unidirectional movement or unidirectional deposition or phagocytosis of collagen.